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Are these claims of "revolutionising" understanding of human vision and hearing valid?
I've started a hobby machine vision project (and posted some questions to this end on other SE sites) and on a side track, also been looking at relevant research in human vision (and partly, hearing).
I came across the work of one "James T Fulton" through an excerpt of a book which claims to have "revolutionised" our understanding of human vision and hearing.
Here are the respective links:

http://neuronresearch.net/vision/

http://www.neuronresearch.net/hearing/
I tried cross-verifying these claims via Google, but nothing turned up on searching either for the author or the book (apart from some Amazon links and very obscure references).
Considering the controversial natural of the claims made here, I would have imagined some level of debate, but the silence I found on the Internet is puzzling. Puzzling, because the sheer level of DETAIL in these books, prevents me from dismissing the claims altogether as well.
Can someone validate some of the content from these books so I can get an idea of the overall legitimacy of the work (and decide if I should continue reading, or not). Below might be a good link to start from:
http://neuronresearch.net/vision/pdf/11Biophenom.pdf
Adding a few examples:

The simplest one - is that the Principle of Univariance is not entirely correct. This is examined on pages 15 through 17 at this link (where I read it):
http://neuronresearch.net/vision/pdf/11Biophenom.pdf
There is this claim quoted verbatim from the site:
"The theory shows that the ARCHITECTURE OF ALL VISION IS TETRACHROMATIC. Although traditionally called trichromats, it is shown that HUMANS ARE BLOCKED TETRACHROMATS"
Caps in original. I just pasted it here to give an idea of the tone of some of the text.
This specific claim is "proven" here (in short):
http://neuronresearch.net/vision/files/tetracomparison.htm

And a longer form of the text is linked in the same page
There is also a theory proposed on why cochlea are coiled:
http://neuronresearch.net/hearing/pdf/coiledcochlea.pdf

Thanks!

Do you have specific questions? Rather than ask people to evaluate all the claims, it would be better to be specific about what you have questions about. Otherwise, I think this is too broad a question. Generally, if it's not in a peer-reviewed journal, I don't give it a second thought. And even if it is, I still give it a careful scouring.

I do agree. I've posted some examples - but the text is perhaps a bit too detailed. The hyperbole screams BS to me, but I'd rather have some factual debunking of one or two of these theories than just go by the tone of the text. I'm open to further opinion on if the question can be pruned down further or if anything else can be done to make it neater.

Skeptics SE would be a better place for this question because it doesn't directly relate to a biological question. For e.g you said that certain article says that human have trichromatic vision with a suppressed vision. A valid question to ask here would be- how does this work ?
But in your post you are asking us to say whether James Fulton is right or not. It is like asking if HG Wells right about his theories.

I agree. Where I am coming from is - he has stated how it works, and I'm asking if that's a valid explanation (I have updated the question a short while back to this end). If Skeptics is a better place for it, I'd be happy to see it moved. Only thing is I'm not sure the expertise for this question will be available at that forum. Maybe CognitiveSciences? Also, I'm not asking if HG Wells was right - that was science fiction. This is something claiming to be science - I just need to know if it really is. Thanks.

a lot of us frequent Skeptics as well, and as the site is fundamentally about applying reasoning and the scientific method to analyze notable claims, there are a lot of people there that shouldn't have any issue with this. Do you want the question migrated, or would you rather frame it afresh there?

And really if it stay's here, perhaps you could break it down into several questions. For Example: "Why are Tetrapods Cochlea Coiled" tagged with Anatomy, Neurology, and Evolution (maybe more).

Thanks, I think moving the question to Skeptics makes sense if it can be better answered there. Once it is moved, I'll see if the question can be pruned further, or broken down into multiple questions as suggested. Honestly though, even one of these theories getting debunked rationally would be enough, since I'm merely trying to understand if there is any scientific merit  to the arguments this person presents or if most of it is hokum. I just don't have the expertise to judge - hence the range of samples (to pick any one and invalidate - or validate! - it)

To move it to Skeptics, the question should be restricted to a single claim, and preferably that claim should be quoted directly. "Revolutionise the understanding of human vision and hearing" is too vague of a claim for Skeptics. But as the question is answered now, and this would invalidate it, I think it is better to not move the question at all.

I agree the question is high-level but the vagueness was due to the scope of the text and the claims being too broad and the difficulty of mapping the (many, many) claims made to the expertise available here. Pruning might still have been possible if I had further subject matter expertise, to narrow the claims down to exactly where my doubts were. But anyway now that the question is answered, it is moot. Thanks for keeping it here, and it is nice to see the decent secondary responses (votes) etc the question and answer have got. Cheers!

This is a great discussion. I, James T. Fulton, am all in favor of such discusssions However, I note a distinctive lack of citations defending the status quo. The site demands that statements of opinion be avoided; that they be backed up with references or personal experience. I have provided thousands of citations to the relevant laboratory investigations, as well as the relevant mathematical formulations. Please look at the appropriate subset of these applicable to your area of interest and then draw your own conclusions. But please provide citations that you rely upon, not just your gut fee

OK, I'll field this one. I'll ignore any of the tell-tale signs of hokum such as writing in ALL CAPS.
Nevertheless, it's a lot of hokum. It's true that he goes into a lot of detail and I'm sure his math looks nice but the fact is that it's not grounded in reality. I would consider myself to be something of an expert (in training) in the field of phototransduction, so I'll focus on claims related to it. However, if he's as sloppy with the rest of the visual process as he is with phototransduction, then his claims are entirely bogus.  I'll just be working from the Synopsis section.
Where to start...How about the first sentence of the "Background" section:

This work originated in the 1960's with the realization that rhodopsin, as then defined, did not meet the requirements for being a chromophore.  It was particularly deficient in the structural characteristics required of a good chromophore.

FALSE. Rhodopsin is not a chromophore and, to my knowledge no one has ever claimed it to be a chromophore. Rhodopsin is a protein. It is coupled with a chromophore, retinal, a form of vitamin A. OK, so if this is the foundation of his research, he is off to a bad start.

The basic assumption had been that the residues of a destructive process could be easily returned to their original state and that state was a simple chemical bond involving only two components in a single molecule...It was assumed that one of the residues was the alcohol or aldehyde of Vitamin A. The other residue was assumed to be a protein and was given the name opsin. Valiant, but unsuccessful, efforts were made to define the nature of the molecule and achieve the formation of rhodopsin in the laboratory.

It absolutely is possible to reconstitute rhodopsin with the chromophore in the lab. This has been going on since at least 1983. Also, the crystal structure of rhodopsin, including the chromophore, was resolved in 2000.

A new class of retinoids was defined by the author at that time, the Rhodonines. This class met the requirements of physical chemistry and photochemistry for a high performance chromophore. However, it was difficult to obtain acceptance of the Rhodonines as a replacement for Rhodopsin within the vision research community.

I have never heard of Rhodonines and web searches only result in his page. Due to his confusion of terminology, I don't know if he is proposing them to be proteins ("replacement for Rhodopsin") or simple chemical molecules ("a high performance chromophore"). If it were the former, one would wonder why Rhodonines were not identified in a comprehensive proteomics assay of the rod outer segment. One would also wonder why rhodopsin is so highly expressed in the outer segment (on the order of 1e8 molecules in mammals and 1e9 molecules in amphibians, more than any other protein in that compartment). If it were the former, one would wonder why there is an entire biochemical cycle dedicated to recycling retinal that takes place just outside the outer segment.
I'll ignore whatever physical state these Rhodonines are supposedly in since they don't exist. I'll also ignore this "Activa" thing. He owns a patent on it, which doesn't bode well for its existence in nature.

The visual system is a very sophisticated system. It uses many of the most sophisticated methodologies known to man at the start of the 21st Century. Failure to recognize these mechanisms and methodologies leads to an inadequate understanding of the overall process.

I'll agree there, with the exception of the use of the word "methodologies"! This isn't engineering, this is biology.

The visual system employs a number of time related processes that have not previously been addressed in the literature. To understand these processes, it is necessary to employ "complex algebra" in the differential equations arena. Employing these techniques provides the complete solution to the overall photoexcitation/de-excitation process within the Outer Segment of the photoreceptor

Phototransduction has a rich history of mathematical modeling. And yes, they involve "complex algebra in the differential equations arena." An excellent review of the first few decades of it can be found in the bible: Phototransduction in vertebrate rods and cones: molecular mechanisms of amplification, recovery and light adaptation. Since that publication, there have been two very nice lineages of models: one comprehensive one that focuses on the proteins (1, 2, 3) and one that focuses on spatial accuracy and stochastic interactions and gives more attention to second messengers (1, 2, 3).

It has also been compounded by the historically poor preparation of the researchers in the field of mathematics.

I challenge him to read one of DiBenedetto's modeling papers and not glow in admiration of his mathematical prowess.

The goal has been to present an overall view of the visual system in a defendable mathematical context and a global scientific framework. This goal has required the introduction of techniques and mechanisms not normally found in the literature of vision. This has been particularly true in two areas, the definition and detailing of the initial photodetection process and a similar detailing of the mechanisms of neural signal transmission. In both cases, the dominance of chemically based concepts is shown to have impeded progress. The description of the visual system, including the neural system, as an entirely electronic, more precisely electrolytic, based system leads to much greater insight into the operation of the visual system than any chemically based theory can offer.

I had to quote in full here. This is entirely bogus. The "initial photodetection process" (phototransduction) is entirely chemical in nature. All of the main players in the process are known and their interactions are largely well understood. Viewing the system as entirely "electronic" ignores the mountains of evidence of all of the proteins participating in it.

Probably the most venerable is that of a dichotomy between types of photoreceptors, the rods and cones. The theory demonstrates in excruciating detail that there is only one functional type of photoreceptor cell and that it is associated with one of four types of chromophore. These chromophores are sensitive in the ultraviolet, the short, the medium and the long wavelength portions of the visual spectrum of light.

The problem with this is that if you look at a retina, you can see rods and cones. You can generate knock-out animals that have only one or the other. Those with only rods cannot handle bright visual stimulii, those with only cones cannot see in the dark. More damning is that you have two distinct phototransduction cascades, separated by evolution dating back to the origins of vertebrates. They share only a few proteins in common and otherwise have unique paralogs performing similar duties. You can isolate individual rod cells and, if you're clever and you have the right species, individual cone cells (they're much smaller and harder to harvest in animals like mice or cows). You can measure their electrophysiological characteristics and find that they are extremely different: cone responses are fast while rods can respond to a single photon of light. Their morphologies are completely different: the rod outer segment is filled with lipid bilayer disks, while that of the cone has a series of in-folds.
As for the whole tetrachromat thing, well, again I have to assume that he's referring to opsins when he talks about chromophores. Thanks to genomics, we can be confident that there are only three cone opsin varieties in old world apes (and one rod opsin). The rest of mammals only have two. If you get into other vertebrates, you'll find more...if you get into invertebrates, you'll find ridiculous numbers. There's not much to say here. A fourth cone opsin protein simply does not exist in the human genome.
So, that's just a quick overview. Do not worry about this guy's research. It is unsubstantiated and exists in a vacuum outside of the rest of the vision research world. I do wish that there were a way for him to work with others. I do wish there were a way for him to integrate current knowledge into his work. But the problem is that his work as it stands simply seems to ignore the wealth of data generated on the visual system and instead treats it as some theoretical circuit.

Thank you. Thanks a lot! This is EXACTLY what I was looking for. Wasted a few valuable hours reading this before hitting some logic walls (I was reading the "11BioPhenom.pdf" I have linked to for some time before hitting the website - which is when the BS alarm went all the way.) The tone and claims were suspect but my lack of actual knowledge prevented me from reading anything more than "harmless grand posturing" into the material. Not much harm done anyway since I was just scouring for some interesting tidbits to explore formally later. Got one - "tremors", for what it's worth.

One thing about the tetrachromat claim: he'll claim that the opsins aren't the proteins of interest anyway, so it doesn't matter how many are in the genome. Of course, as I already showed, we can be confident that yes, the opsins are the light recepting proteins in phototransduction.

My pleasure. I was just glad to see a question pop up in one of my specialties. It was actually interesting for me to read his claims.

Also, +1 for this :) - "I'll also ignore this "Activa" thing. He owns a patent on it, which doesn't bode well for its existence in nature."

One more comment: if we only had one type of photoreceptor cell that contained four different light-sensitive molecules, we wouldn't be able to discern different colors. All of the light-sensitive molecules would be activating the same pathway! It would be like four light switches attached to the same light. When the light is on, if you don't look at the switches, you won't know which one even turned it on.

I guess it would theoretically be possible if the cells were eventually connected in the right excitatory/inhibitory configurations, and only one of these molecules was "activated" per such cell. But I guess there is enough evidence the other way (there being multiple types of photoreceptors) for one to not worry about this specific argument?

That would require four separate signaling pathways within the cell, working with four different second messengers. The way it really works is that the hydrolysis of cGMP causes some ion channels to close, which causes a drop in Ca2+ concentrations (it's being constantly extruded). This results in a membrane potential. If all four hypothetical receptors worked the same way, they'd close the same channels and the cell would hyperpolarize in the same way for all four, looking no different to the bipolar cells...

Didn't know the details of the operation. Guess it's time for me to shut up and leave the comments for any further productive inputs. :) Thanks again.


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What does "fit" mean in "survival of the fittest"?
What does "fit" mean in "survival of the fittest"?

This is a very vague question. What aspect of fitness do you not understand?

'Survival of the fittest' has never really made sense, because it confuses the scientific (evo. biological) and colloquial definitions of the word - which some of the previous posters have also done.
Biological fitness simply refers to an individuals genetic contribution to the following generation. That is, a 'fitter' individual, in an evolutionary sense, is one whose genetic material is proportionally overrepresented in the next generation.
The mechanism by which an individual achieves this may include out-surviving competitors, but it's certainly not the only way to increase fitness. Two individuals may live for the same length of time, but one may successfully court more females, or out-compete the other for food resources, for example. So when we refer to a 'fitter' individual (or individuals), we're saying nothing about why they are so. It's not a comment on their 'fitness' in the human sense of the word (bigger, stronger, longer-living), it simply refers to how well they pass on their genetic material.
So you can see why the phrase is nonsense. If we're being precise, then 'survival of the fittest' translates to 'survival of the individual who is better able to pass on their genetic material to the next generation' - which is meaningless because it tangles up these different concepts.

+1 for paragraphs 2 and 3. However, I wonder, does being recursive/tautological still make it "nonsense"? Hesperus is Phosphorus

"Survival of the fittest" is a misnomer.  It's "Reproduction of the fittest".  Nobody survives in the end :)

I would have liked to write an answer, but the question is closed already. Anyway: "fittest" is the one that "fits most". It has nothing to do with strength or endurance, but (popular example) it can be a fly without wings on a stormy island.

Simply put, "fit" refers to being adept at finding and utilizing resources, evading predation and producing offspring.

It might sound tautological, but fitness is pretty much defined as 'being more likely to survive - and reproduce'; fitness is surviving and survival goes to the fittest.
This is a trite way of citing Richard Dawkins' theory of the replicator to describe fitness.
Fitness is a property of being able to carry one's genes to a later generation.  Fitness is result of the individual properties and how well the individual can get along in the environment that it finds itself, in comparison to other individuals who might be competing for resources in that environment.
There is no concrete definition of fitness.  Fitness can mean size and strength, or lightness and resilience, short or long life.  There is no a priori way of looking at two individuals you know nothing about and deciding which is going to be more successful at reproducing.
not sure this is better, but there's definitely more of it...

Survival of the one, who is more likely to survive. That's recursive. Can you elaborate?

@Zurechtweiser: I think there is a bit of confusion on the fact that it is not the survival of a specific individual per se which is important, but rather the survival of its genes in the population. There is no recursion there, the individual(s) who are more likely to transmit their genes (i.e. to make them "survive" to next generations) are the fittest.

you're right that this is a bit trite - i had only a minute or two to tap something out.  I've added a bit more.

I still think you're off the mark, particularly in paragraph  4. There is a fairly simple definition of biological fitness, namely, an individuals relative success in passing on their genetic material (as I've outlined in my answer). And no, biological fitness can not '...mean size and strength, or lightness and resilience...'. Those are factors which may influence fitness but they are not integral to the definition of 'evolutionary fitness', which is what we are discussing. Measuring fitness can be very difficult, which you rightly touch on at the end, but defining it is simple enough.

It's worth reading the Wikipedia page on this.

Also recommend "The Extended Phenotype". @ThomasWhite I think this is what I said.  I did change one word tho.

Rather than "fitter", I'd say "better". Better at hunting, gathering food, surviving predators, surviving weather conditions or other kinds of population pressures. The better a population gets at the above things, the more (and fitter/better) offspring it is likely to have and the pyramid goes on.
In some cases, mutations might simply confer a "new" advantage that there was no prior pressure in the system for. For example, I can easily imagine a bird population where one of them evolves a plumage/pigment mutation that gives it a selection advantage and it quickly becomes the norm. This mutation could have - theoretically, and in my view - evolved even in the ABSENCE of a sexual selection pressure.
It's just that natural selection (in my simplistic interpretation) "favors" any improvements in organisms in a really simple, statistical way.

Often it is re-phrased "Survival of the Most Adapted."  Fittest might make you think of the strongest or the fastest, but suppose in extreme famine, those who had better regulation of muscle growth could have more surviving generations.  In an over abundance of resources the reverse could be true.
Ultimately in natural selection, it's all about getting your genetic information to as many surviving copies or permutations as you can. Many organisms use DNA to hold the information, but there are other options (RNA viruses for example).
Getting back to the phrase: It's saying that the fittest is the one who continually replicates well in the current environment/surroundings.  Ecosystems are often changing, thus who has the best fitness will change as the ecosystems changes.  When an ecosystem is stable for a long period of time, you will find highly adapted organisms to that ecosystem.  This is because the selection towards "fittest" has been applied to many, many generations.

Whoops I just saw the previous two answers come up while I was writing.  I won't be insulted if people think this should be delete as too similar.

While, as others point out, "survival of the fittest" is a pithy description of the theory rather than an actual serious statement I think it can be converted to a useful definition relatively easily.
There is substantial debate about how, exactly, fitness should be defined. I'm not enough of an expert to want to try and lay out the complications here but I will give my preferred definition:

The fitness of an organism is defined as the number of its
  grandchildren that make it to adulthood (or that number divided by two
  for sexual organisms).

This has the advantage of being amenable to experimental investigation and intuitively simple while complex enough to avoid simple problems arising from the differences in offspring number and the question of infertile offspring.

Where is that definition coming from?

A book on the philosophy of evolution I read a while back. I don't have it to hand to give you a reference.

Such definitions will always be lacking, in my opinion. For example, what if an organism has tons of grandchildren but they are all sterile?

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Identification of this humpbacked, brown, clawed insect climbing up my wall?
I noticed several of these guys outside, all in a vertical position clinging to a wall. I didn't come to them too closely, but my immediate reaction was that they are scorpions.

I thought that maybe it's a curled-up scorpion, or maybe there's some kind of particular scorpion that is this circular in shape? These are probably silly conclusions, but I'm not an expert in this field. I would really appreciate the insight of a professional!
thanks very much.

Could you add some additional information like where you are located and the size of the organism in question?

That's the exoskeleton (shed outer shell) of a young cicada, left behind when it emerged as an adult and (we can imagine) flew off somewhere to sing, and find a mate.
This article on EarthSky has a nice description of the big cicada hatch this summer (2013), and also a great picture of an adult cicada emerging from the exoskeleton. However, this article and other recent news about cicadas mostly deals with the Eastern US genus Magicicada, and it's likely that in Arizona you're seeing a different genus (that is, a different type of cicada).
You'd probably have to find an adult in order to identify exactly what genus and species of cicada you've got. Alternatively, you could listen for their songs – this site has examples of calls from many Western US species, including the Apache Cicada Diceroprocta apache, which seems to be a common cicada in your area.

I wanted to add a more thorough answer to this post (with some pictures) since they are bound to get a lot of press (and questions) this summer (2021) -- more on that later....
Short answer
This is the abandoned exoskeleton (called an "exuviae") of a molted cicada nymph.

 Credit: Valeriy Kirsanov/Fotolia, Britannica.com
Here is a time-lapse of one molting:

 Credit: T. Nathan Mundhenk (July 2007 in Centerville, Ohio USA)
Long answer
Cicadas are a superfamily of insects of the true bug (Hemiptera) order; most species are in the family  Cicadidae.

Cicada Mania provides a nice list of North American species with photos, audio, characteristics, and ranges. (It's really an excellent resource for cicadas!)

They list Cacama valvata (common cactus dodger), Diceroprocta apache (Citrus cicada), Okanagana bella (mountain cicada), and Pacarina puella as common Arizona species. However, Sanborn & Phillips (2013)1 makes clear there are more than 50 species found in Arizona, so I will not try IDing the OP's specimen to species.

Life cycle
Cicadas actually live most of their lives underground as immature nymphs. They feed by sucking out xylem from plant roots. Their enlarged claw-like forelimbs are used for digging in the soil in which they live and for excavating chambers near food sources [source]. After 2-17 years (see below) underground, the nymphs emerge, crawl up a vertical structure, and molt for the 5th time into their final adult stage. Their exuviae are often left clinging to the plant (or wall) after molting due to the relatively sharp tarsal claws they use for anchoring and climbing. Adults often live for multiple weeks: sucking on xylem from aboveground plant structures, mating, and depositing eggs in branches. After eggs hatch, nymphs drop to the soil below, and begin their multi-year subterranean life.

 Life cycle of periodic cicada; Credit: Roy Troutman and Elias Bonaros, cicadamania

 Nymph crawling up tree; Source: Peggy Notebart Nature Museum
Annual vs 13- and 17-Year Cicadas:
In North America, there is a need to distinguish between "annual" and "periodic" species of cicadas. Annual cicada species can be found essentially every single summer (although their life cycle is 2-5 years, there are enough overlapping broods that one can see them annually).
Periodic cicadas (genus Magicada), on the other hand, spend most of their lives living underground and synchronously arise only every 13 or 17 years depending on species and brood (13-year species more common in SE US and 17-year species more common in NE and midwestern US). They survive by sucking on xylem from deciduous tree roots.2. These periodic cicadas are unique to the Eastern US, and such long life cycles aren't found in insects anywhere else in the world.
These two subgroups of cicadas are easy to tell apart as a number of species of annual cicadas tend to be larger and green-hued whereas the periodic species are smaller, black-bodied, and have very conspicuous red eyes and tinted wings. Even the few darker annual species (e.g., Diceroprocta apache and various Okanagana species) lack the bright red eyes and red/orange-tinted wings seen in the periodic species.

 Image sources: (L): Purdue Extension; (R): Carol Toman on whatsthatbug.com
The swarm is coming back!!
Periodic cicadas have the longest life-cycles of any insect, and their almost magical synchronous emergence every 13 or 17 years always captures the attention of many media sources and social circles/media. However, some of you may wonder: "wait, has it really been 17 years since we last saw these insects?..."
Well, the answer could be yes if you live in the right place, haven't moved, and haven't turned on your TV/computer lately. However, in certain areas, it's possible to see these insects more frequently! You see, there are actually multiple broods of these insects -- essentially separate populations -- that arise at different times.

The brood that is making all the media hype for emerging in 2021 is Brood X:

[The various species of North American cicadas] form mixed-species cohorts called broods whose members arise like clockwork on the same schedule. The broods are identified by Roman numerals. Brood X is the largest of the 12 broods of 17-year cicadas, which emerge in different years. Scientific American

 Brood map for periodic cicadas. Source: Liebhold et al (2013)3 US Forest Service
As you can see, Brood X can be found in 10-11 states ranging from New Jersey to Illinois.
You can read more about periodic cicada broods on Wikipedia, and you can see range maps of both 13- and 17-year species here (from here).

Citations:
 1. Sanborn, A.F. and Phillips, P.K., 2013. Biogeography of the cicadas (Hemiptera: Cicadidae) of North America, north of Mexico. Diversity, 5(2), pp.166-239.
 2. Lloyd, M. and Dybas, H.S., 1966. The periodical cicada problem. I. Population ecology. Evolution, 20(2), pp.133-149.
 3. Liebhold, A. M., Bohne, M. J., and R. L. Lilja. 2013. Active Periodical Cicada Broods of the United States. USDA Forest Service
Northern Research Station, Northeastern Area State and Private Forestry.

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Preparation of normal DNA polymerase
i don't need Taq polymerase. Just need normal DNA polymerase. So the main idea is preparation polymerase directly from Lactobacillus without using cloned vector. My idea is electrophoresis using agarose gel and calculating the isoelectric point of Polymerase based on protein sequence to know where they will migrate after electrophoresis. Is it possible for this idea ?

I think it would be easier to use heterologuous expression of a tagged protein, e.g., a His-tag. You could then easily extract that protein from the lysates using a Ni-column. There are many more tags available, but the His-tag is the most common one.

I guess this is still related to your DIY project, you should specify it, otherwise people will assume you are in a standard lab with full access to state of the art equipment. 'Normal' DNA polymerase is not thermostable. It will be inactivated at the first cycle of PCR, that's why most polymerase we currently use comes from organisms that live in very hot environments.

@GianpaoloR I'm running another experiment so taq polymerase for PCR is not necessary now. In this experiment i need to using normal DNA polymerase because normal DNA polymerase can synthesis in room temperature but taq polymerase not. No matter if other method could help me to learning more about biology even it's impossible for me.

This is a very ambitious project for a DIY-er. To explain why, I'm going to use the example of DNA polymerase I from E. coli.
DNA polymerase I is the most abundant DNA polymerase in the E. coli cell, but nevertheless is still only present at around 300 copies per cell

Ishihama Y et al. (2008) Protein abundance profiling of the Escherichia coli cytosol. BMC Genomics. 9:102.

This was the first DNA polymerase that was ever purified, in the laboratory of Arthur Kornberg

(Enzymatic Synthesis of Deoxyribonucleic Acid : I. PREPARATION OF SUBSTRATES AND PARTIAL PURIFICATION OF AN ENZYME FROM ESCHERICHIA COLI Lehman, MJ et al. (1958) J. Biol. Chem. 33:163-170.).

In this paper a method of purification is described that starts with 60 litres of culture. There is also this statement:

"One kilo of E. coli yields less than 10 mg of the purified enzyme."

I'm guessing that you have no experience of protein purification, so I'll just tell you that this is very discouraging: these days, with overexpression, people expect to get mg quantities of their protein from just a few grams of bacterial cells.
This is a clear illustration of why it is pretty much unthinkable for you to set out to purify an enzyme like this using small-scale methods, and explains why techniques of overexpression and the use of affinity tags have revolutionised protein purification.
And it gets worse: even if you did manage to purify some DNA polymerase I from a bacterial source you would find that it is actually not very good at making DNA. This is because as well as extending primers in a 5'>3' direction, it is is very good at degrading DNA in the same direction. In other words as the enzyme moves along a template molecule, copying it, it will degrade any existing DNA that it meets "ahead" of its direction of travel. This is why the most commonly-used form of this enzyme in research is the "Klenow fragment", a fragment of the polymerase that lacks the 5'>3' exonuclease activity. This fragment was originally made by treating DNA polymerase I with the protease subtilisin, but it is now expressed from an engineered polA gene. Klenow fragment polymerase was used in the original PCR experiments (it had to be added afresh at every cycle).
I don't know how much money you have to spend on your projects, but in fact these enzymes can now be bought relatively cheaply.  I don't think that you can expect to make them for yourself, without this becoming the actual project.
Finally, if you can get hold of a strain of E. coli with an expression plasmid for Taq polymerase then you really could make your own very easily - I've done this myself (but I no longer have the strain) and the heat stability of the enzyme makes the purification trivial. It would be much easier to use your own Taq with a heated water bath than to try to make DNA polymerase I. But obviously it depends upon what you are trying to do: Taq polymerase may be unsuitable for other reasons.

Incidentally - I perhaps haven't made it clear that although you don't need mg of enzyme for typical molecular biological applications, it is impractical to purify very small amounts of a protein.

Thank Alan Boyd so much, you always give me a quality answer for my question and give me a direction what i need to do next. I'm planning to create a DNA sequencer, the main idea for my project is heat the tube to 95 oC -> 60 oC for primer can bind. And then cool down to 37 oC for normal polymerase can work. I need temperature room because i think one of my sensor chip can not work in high temperature. I never work with plasmid before and it's seem that i need to get used to it.

I'm an IT engineer and all of my worked money is being spent for research biology. A lot of money was spent and i want to save money as possible for my future research. Enzymes are very expensive for me as the price i see in this table at http://www.enzymatics.com/products.htm . However it cannot make me downhearted.

@ĐứcUltraSoft: if you want to do some research then the best option would be to work as an intern in some lab where you may also implement your ideas. Biological research especially molecular biology is a costly affair and you may end up losing more money.
I think that you can write to George Whitesides who is in Harvard. His lab is into bio-entrepreneurship.

@AlanBoyd do you how many molecule of taq polymerase is needed for a PCR reaction ?


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How to learn biomathematics?
I'm currently an undergraduate math student and researching on the internet I discover that exists an area called "biomathematics". Looks so interesting. They use the graph theory and topology to describe the cells and DNA structure. Was love at first sight, because I really love maths and biology.
I'm reading the book "Clinically Oriented Anatomy" of Keith L. Moore and "Essential Cells Biology" of Bruce Alberts, but I don't know if I'm doing right. If anyone know how to start to learn this science I would really appreciate it.

Moore is a human anatomy text and is unlikely to be helpful for Mathematical Biology (but a great book for human anatomy).

@kmm I don't know if is necessary to have some anatomy knowledge, because I think that is important to know where are located the parts of human body...

This is highly relevant: http://biology.stackexchange.com/questions/9102/suitable-introductory-book-on-bioinformatics-for-a-computer-scientist

MathsBio is quite a large field. It is an interdisciplinary branch having utility in a lot of branches in biology like biophysics, biomedical, genetics and molecular biology. Applied  Mathematics is generally used in modelling and understanding biological phenomena where we have to deal with large amount of data, for example the use of graph theory for analysing biochemical networks. Systems biology is an emerging field which uses a lot of mathematics.
You should pick a book depending on the field in which you want to use mathematics, though having knowledge of elementary biology is necessary. I am suggesting some books which cover wide application of mathematics in biology.
Mathematical Biology: I. An Introduction by JD Murray
For systems biology:
Mathematical Modelling in Systems Biology: An Introduction by Brian Ingalls

I have taken Brian Ingalls class.  It is largely mass action kinetics with some dynamical systems considerations as far as the mathematics goes.
In other words, it's largely systems of differential equations.

I took the General Chemistry class, because I want to have Biochemistry (have pre-requisites, Organic Chemistry I and II).

I second the suggestion of Murray's Mathematical biology - great introduction with large coverage.

I really like "A Biologist's Guide to Mathematical Modeling in Ecology and Evolution" by
Sarah P. Otto & Troy Day, although it's more specific to Biology and Evolution - which may have been the first field in biology to use mathematics.


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What exactly is the neural receptive field?
Neural receptive fields map the spatial or temporal distribution of the data to individual neuron excitation, if I understand correctly, but I do not understand if receptive fields (especially in the higher cognitive areas such as the various layers of the visual cortex, etc.) are:

Actual structural distributions of neurons that help map specific spatial or temporal properties of stimuli (such as concentric arrangement for contrast detection, rectangular arrangement for orientation detection, or movement detection, etc.), or,
Merely a mapping of the structure of the stimuli that can excite specific neurons.

If it's the latter, isn't it basically as simple as a pattern/feature/vector that individual neurons are sensitive to?

No, it is not 1. the structural distribution of the neurons themselves.  If by mapping you mean a kind of function that maps real space to cognitive space (or such) then it is not that either (at least, not explicitly/directly).
The receptive field is the region of 3D space in which sensory neurons can make their relevant detection.  It's not a pattern/feature/vector, just the coordinates defining some spatial region itself.
For example, take the neurons making up your audio sensory system.  If an object is making noise and you can hear it, then that object is within the receptive field of the hair cells responsible for the audible frequencies.  That is, the object's physical location is within the spatial coordinates that define your audio system's perceptive field.
Fun fact: for two sounds of the same amplitude, lower frequency detecting hair cells tend to have a larger receptive field since lower frequency signals travel farther.  In other words, the receptive field is somewhat dependent on the quality of the source of perception, not just the sensory neurons.
It's strange terminology coming from physics, because we generally define "fields" by sources, not by receivers.  An audio source has an unambiguous "field" of acoustic radiation.  A receiver does not generate a field but is sensitive to a certain threshold of field quantity.  So to define the field as something coming from the receivers (the sensory neurons) is an unintuitive idea.

I think I'm understanding this, but just to make sure I grasp the implications. There are studies that map specific shapes and orientation of receptive fields to excitation/inhibition of specific neurons. Does this mean there's a running thery that specific neuronal clusters are "programmed" (or have evolved) to detect stimuli from specific receptive fields within the field of view (in case of vision) of an organism? For example, upper, lower hemisphere. Rectangle oriented at 30 degrees, etc. Reference: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1987328/#!po=14.0000

I think that's kind of a philosophical question. "Evolved to" and "programmed" have a really goal-directed connotation to them.  Maybe you mean "selected for".  I don't know the evolutionary evidence for selective pressures on receptive fields.  Intuitively, you'd think that the strategies animals adopt using their available hardware is somehow selected for, but in some cases it could just be consequence of another adaptation that happens to be useful, couldn't it?  I think this is a new question you should submit formally and allow evolutionary scientists to answer.

I think is closer to 2. It is the subset of sensory space that elicits a reaction in a given neural population.
So you should:

Pick your neural population. Usually it is a single neuron (but can be easily extrapolated to bigger populations). It may be a sensory neuron, or a neuron in a higher processing region.
Determine your sensory space. That is, you should decide the kind of stimuli you'll be dealing with. For example, not only "visual stimuli", but you should identify the parameters, or independent variables, you will vary in your experiment.
Define a criterion to discriminate between reaction and non-reaction. This implies to choose what is the dependent variable in your study (for example neuron firing rate). Then you could define what features in the relation $\frac{dependent\:variables}{independent\:variables}$ you will search for. That is the tuning curve (which well may be a high dimensional curve).
Perform your experiment and analyze your curve. The region of parameters (independent variables) whose reaction goes above threshold according to your criterion is the receptive field. Sometimes is not trivial to define such a criterion (see: http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.0040092)

A good general reference is the article in Scholarpedia: http://www.scholarpedia.org/article/Receptive_field
This type of analysis is very useful for position coding, that is, when you expect that the activation of a specific region in the brain correlates to stimuli in a region of sensory space. But sometimes things are more complicated (e.g Olfactory coding http://www.jneurosci.org/content/30/27/9017.full).

Stick a probe in your neuron-of-interest. Now stimulate the organisms in some way.
All the stimuli that make your neuron fire are the neuron's receptive field.
Example 1:
You probe a neuron in the primary sensory cortex of a human subject. Next, you stimulate the patient with light touch to their skin. Let's say you find that the neuron only fires when you stimulate the right thumb. Thus, light touch to the right thumb is that neuron's receptive field. The neuron doesn't fire to light touch to any other part of the body.
Example 2:
You probe a neuron in the primary auditory ganglion. Next you stimulate the patient with different sound frequencies. The neuron only fires at only a narrow band of sound frequencies. The receptive field of that neuron is that specific band of sound frequencies.


text:
How can we distinguish blended flavors?
As far as I know, humans can distinguish between 5 basic tastes based on various molecules in food and their interactions. There's a level to all 5 so there can be an endless variety of tastes, and we can recognize them with some precision. What surprises me is that we can often distinguish the original flavors in a mix - for example in a salad or even more so in a blended juice. Shouldn't we perceive an entirely new flavor having the average of each basic taste?
Not entirely sure this belongs on a biology forum, but I hope someone can explain :)

We can distinguish these five tastes, but smell many more. The nose takes a big part in the tasting process, this is why lemon tastes like lemon, and not just sour.

You're talking about the difference between "taste" and "flavor." In common speech we use these words synonymously, but they actually mean different things.
Taste refers to the five sensations your tongue can detect -- sweet, sour, salty, bitter and umami. There's growing evidence for a sixth taste, "fat."
Flavor refers to the combination of several factors:
1) taste, as just described,
2) the aromas of esters, flavinoids, ketones, and other compounds in your food, detected by the nose. This happens a) before you take a bite, and b) as you chew and swallow, releasing different compounds and higher concentrations into your nose through your retronasal passage,
3) physical sensations such as texture, heat and cold, visual appearance and even sound (for example, the crunch of celery or potato chips)
4) chemesthetic effects, like the astringency of tannins or the "artificial" heat of chili peppers. (The compound responsible for chili heat actually down-regulates physical heat receptors so they're more sensitive. Menthol up-regulates them to create a cooling sensation.)
5) Emotional and social factors, like the memory of your grandmother's homebaked bread, or many people's aversion to raw fish.
All of this put together is why blackberries and strawberries are both sweet and tart, yet blackberries taste like blackberries and strawberries taste like strawberries.
Hope that helps!
References:
-- The collected works of Karen Page & Andrew Dornenburg
-- "Tastebuds And Molecules," Francois Chartier
-- LOTS of personal empirical evidence (I'm a chef)


text:
Do toxin producing strains of E. coli constantly produce toxin or only under certain conditions?
Background
E. coli is prevalent everywhere but only some strains produce toxins harmful to humans, such as E. coli O157:H7.
Questions
1) Would anyone know if these strains are always producing this toxin or is it only under certain conditions?
2) Is it the toxin itself that makes people sick and not the presence of the bacteria?

1) That depends on the fact, if the protein in the bacterium is regulated somehow or it is constantly expressed. That could be different for different toxins and even for the same toxins in different strains, so there is no  plain answer for all strains and toxins.
2) That, I guess, also depends on the toxin. There are some that are basically toxins, but do not make people sick. Sometimes, the toxin is produced by the bacterium, but never secreted. Sometimes it is secreted, but has no influence on the host. Sometimes the host does react to a toxin. But the human immune system can also react to the bacteria before they start producing toxin (if it is somehow regulated) or before the toxin concentration secreted by the bacteria starts to be harmful.
In the case of E. coli O157:H7, this paper states it produces two different Shigatoxins (that were supposedly causing its pathogeny), but also some other toxins/toxin-like proteins.
I have studied some E.coli genomes previously, some non-pathogenic had several toxin-related genes, some pathogenic had actually none at all (at least none that could be annotated).

Thanks. I'm looking over that paper. In your research did you ever come across some info as to what E.coli uses it's toxin for? I might actually just post that as a separate question..

I was not quite interested in the Shigatoxines, as they did not occur in the specific strain I was mainly interested in. I guess, secreting toxines is basically a fitness factor, as it could kill off competitors for nutrients.


text:
Diabetes-diabetes comorbidity
Is it possible to have both type-1 (insulin-dependent) and type-2 (non-insulin-dependent) diabetes mellitus? That is, to have both insulin resistance and zero (or negligible) insulin production? If not, why not? And if so, then how common is this (among humans with each type of diabetes)? Any information on why the comorbidity may be high or low is also most welcome.

I've been thinking about the "how common" part of your question, and it's tricky to awnser world wide as we see significant cultural variation.  Perhaps you would settle for prevalence in a group of countries you are interested in?

@AtlLED, any answer that answers that part of the question about any region would be most welcome.

Yes you could think of an individual as having both(1).  A good place to start looking at "newer" diabetes other than the classic 1 and 2 is latent autoimmune diabetes (LADA).  Though, I don't know if one would say you had no insulin production.  It would seem as though patients exhibit some characteristics of both types(2), and indeed there maybe a continuum possible(3) between ether "pure" type on each extreme.
(1) The type 2 diabetes-associated variant in TCF7L2 is associated with latent autoimmune diabetes in adult Europeans and the gene effect is modified by obesity: a meta-analysis and an individual study. Diabetologia. 2012 Mar;55(3):689-93. doi: 10.1007/s00125-011-2378-z. Epub 2011 Nov 23.
(2) Latent autoimmune diabetes (LADA) is perched between type 1 and type 2: evidence from adults in one region of Spain. Diabetes/Metabolism Research and Reviews 2013; 1520-7560.
(3) Latent autoimmune diabetes in adults: evidences for diabetes spectrum?.Chin Med J 2013;126:783-788

Latent autoimmune diabetes is interesting and even answers my question, but I was thinking more of, and looking for, cases of independently contracted types 1 and 2 diabetes.


text:
Information and image of Genus Acesina
I am searching for image and information, like distribution etc of the genus Acesina. The Taxonomic tree is:
Kingdom:        Animalia
Phylum:         Arthropoda
Class:          Insecta
Order:          Lepidoptera
Superfamily:    Papilionoidea
Family:         Lycaenidae
Genus:          Acesina

According to Catalogue of Life this genus has the 4 species. I haven't found any information by searching web, even the species are extinct or not! Any pointer would be appreciated.

@kmm thank you for the information. Can you post your comment as the answer, so that I can accept it.

Also described at  http://en.wikipedia.org/wiki/Acesina

The genus Acesina has been revised and is now part of the genus Arhopala. The wikipedia page for Arhopala has some additional information on this genus.


text:
Problem on finding sequence of Taq polymerase
As i know, Taq Polymerase can be found in Thermus aquaticus, so i do a search for protein list of Thermus aquaticus and have this : http://www.ncbi.nlm.nih.gov/genome/proteins/1724?project_id=55053 . After filter for 'polymerase' i found a lot of protein named polymerase :

DNA polymerase beta domain protein region
DNA polymerase I
DNA polymerase III, alpha subunit
DNA polymerase III, beta subunit
DNA polymerase III, delta subunit
DNA-directed DNA polymerase
-.....

I don't know what they mean and which is the protein i'm looking for ?

After click on one of them i have the sequence not in A-T-G-X format :
ORIGIN
        1 msgvdallll gvelsraiit aysvyaivli lggflarlpt rweervealg gsfylagvil
       61 wryyaggday dldlflrasg mallvlprlv rvvlreyggg r
What does it mean and how to working with it ?

According to the paper here "Taq polymerase" is the DNA polymerase I from Thermus aquaticus. (Incidentally the paper has the complete sequence of the gene in question.)
You can find a protein sequence entry at NCBI here. This shows the sequence of amino acids in the protein, not the DNA sequence of the gene. Several lines from the top you will see:

DBSOURCE    locus TTHDNAP accession D32013.1

with the last word highlighted as a link. Follow that link to the DNA sequence. That entry includes the line:

CDS             1..2499

which tells you that the initiator ATG of the gene is right at the start of the sequence shown, but that the 3026 bp sequence includes a lot of downstream DNA. If you click on CDS on that line it will highlight the coding sequence in the DNA.
A very cursory comparison of this sequence with the one in the paper that I linked to suggests that this is the same gene.

Thank Alan Boyd so much, below is the answer for these protein code mean:
    A  alanine               P  proline
    B  aspartate/asparagine  Q  glutamine
    C  cystine               R  arginine
    D  aspartate             S  serine
    E  glutamate             T  threonine
    F  phenylalanine         U  selenocysteine
    G  glycine               V  valine
    H  histidine             W  tryptophan
    I  isoleucine            Y  tyrosine
    K  lysine                Z  glutamate/glutamine
    L  leucine               X  any
    M  methionine            *  translation stop
    N  asparagine            -  gap of indeterminate length

Source from NCBI : http://www.ncbi.nlm.nih.gov/BLAST/blastcgihelp.shtml


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Why do cell membranes have a lipid bilayer instead of a monolayer?
Many cells have a cell membrane composed of two layers of lipids. Why is it that they have two layers and not just one?
What purpose do this arrangement serve?

Why use membranes?
Compartmentalising the cell has lots of advantages and purposes. In Koshland's 2002 essay, compartmentalisation was described as one of the seven fundamental pillars of life. Broadly speaking, membranes create different sets of conditions (chemical and biological) inside the cells. This allows more efficient functioning and advanced catabolic and metabolic processing. More complex and adaptable systems were thusly achieved by the evolutionary process.
Why a bi-layer?
There have been several molecular dynamic simulations such as this one carried out to investigate the biophysicochemistry of spontaneous bilayer assembly. There, lipids start in random orientations. The ordered bilayers we know and love spontaneously assemble in under 100ns. What's actually happening at a molecular dynamics level is the self-association of the hydrophobic lipid tail groups driven entropically by water. In other words the polar (hydrophilic) head-groups "prefer" interacting with the water (called the interfacial region) and the the hydrophobic tail groups "prefer" not interacting with the water. With those two preferences in play, the lipid bilayer forms.

On a smaller scale, micelles also form spontaneously, but this doesn't offer the compartmentalization required for biological functions.

It would appear that the conditions for an ordered bilayer are so favorable that they take precedence over any other orientation or combination. One apparent exception is the archael monolayer. Do see @WYSIWYG's answer that refers to the exceptional extremophiles that use a monolayer. Their comment summarises the monolayer succinctly:

They are technically monolayer but resemble bilayer. Like bilayer connected via a covalent bond. These membrane lipids have two hydrophilic heads and a hydrophobic "torso".

Image sources

Image 1: http://www.perkepi.com/cell-membrane/
Image 2: https://en.wikipedia.org/wiki/Lipid_bilayer

Why Bilayer and not a Monolayer
Lipid monolayer vesicles are possible as you mentioned (for example micelles). However, you have to understand that the cellular interior i.e. the cytoplasm, is aqueous and therefore a monolayer vesicle like micelles would not work. In micelles, the two compartments - interior and exterior, have to be of opposite nature for the stability of the micelle. In other words, you cannot have an aqueous environment inside a regular micelle. Conversely, you cannot have a non-polar environment inside an inverse-micelle.
Since both the exterior and the interior of a cell are aqueous, both the membrane surfaces have to be hydrophilic. This is possible only in case of a bilayer of usual amphipathic lipids with a hydrophilic head and a hydrophobic tail. However, monolayers are possible in lipids which have two hydrophilic "heads" at both ends and a connecting hydrophobic "torso". Such lipids are found in certain archaea such as Thermoplasma and Ferroplasma, like Miguel mentioned (see this article for more details). As you can notice, these monolayer membranes would be more rigid than bilayers which may be the reason why they evolved in extremophilic archaea.

 Albers, Sonja-Verena, and Benjamin H. Meyer. "The archaeal cell envelope." Nature Reviews Microbiology 9.6 (2011): 414-426.

Actually there are monolayers in some extremophilic archeon, wich have both layers of the regular membranes attached by covalent bonds.
However, the main reason is that membranes are formed by virtue of hydrophobic interactions. Phospholipids are amphipathic mollecules wich have a polar "head" (given by the negative charge of the phosphate group) and an hydrophobic "tail" (usually two alliphatic chains).
The mollecule tries to avoid the state of minimal entropy, wich in this case would be to "swim" freely in the water. In this hypothetical state, water mollecules would need to orientate themselves in order to minimize the contact with the hydrophobic tail (wich are very big mollecular gropus who doesn't atract the polar water mollecules) and to maximize the contact with the polar head. If this mollecule finds more mollecules of their kind they will stick together by their hydrophobic tails, because that will reduce the urge to organize water mollecules, and by so, raising the entropy of the system. There are some posible conformation wich allow to do this, and one or other will produce depending of the composition of the lipid mix.
Lastly, membranes serve mainly as selective barriers wich separate the internal cell, whose conditions are regulated, and the outside. Membranes can have embeded enzymatical systems, such as photosystems, respiratory chains or some key metabolic paths. Also, they usually contain sensitive proteins who respond to the external condictions and regulate the behaviour of the cell. Other functions can be found, but those are the most important.

Could you add a citation for the extremophilic archeon that use monolayers? It sounds impossible (as much of the extremophilic stuff does)!

@GoodGravy is correct, it sound impossible to get 'living' organism inside single lipid layer. References will be good.

@James and Dexter. They are technically monolayer but resemble bilayer. Like bilayer connected via a covalent bond. These membrane lipids have two hydrophilic heads and a hydrophobic "torso".

@WYSIWYG Thanks for the clarification. A quick Google scholar search provides some interesting papers on this also.


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Why do kefir grains stop growing in soy milk?
Kefir is a fermented milk drink made with kefir grains. It usually is prepared by inoculating cow, goat or sheep milk with kefir grains.
I would like to prepare the drink with soy milk, which worked fine for some months. Then the kefir grain stagnated in its growth. I use bottled soy milk from the supermarket. I do not produce the soy milk by myself.
In "real" milk the kefir grains never stop growing (and dividing), but in soy milk they apparently do.
Why do the kefir grains stop growing in soy milk? Are they lacking a specific nutrient that is only contained in milk from animals?

Animal Milk. The ideal environment for Kefir Grains is animal milk. Varieties include cow, goat, sheep, and other similar species. Kefir Grains thrive in animal milk due to the chemical makeup of the liquid. The lactose in animal milk provides the most efficient food source for the Kefir Grains and therefore the most efficient and effective culturing process.
Alternative Milks. While animal-based milks are the healthiest for the Kefir Grains, alternative types of “milk” (coconut, soy, rice, nut, etc.) can also be used under certain conditions. Generally speaking, Coconut Milk, Soy Milk, and Rice Milk can be cultured using Kefir Grains as long as a revitalization period is observed (see below). While some people report success culturing Kefir Grains in seed and nut milks (e.g. hemp milk, almond milk, etc.), these varieties tend to yield more inconsistent results.
Revitalization Period. When using a non-animal variety of milk, it is important to occasionally allow the Kefir Grains to revitalize in animal milk for 24 hours.
We recommend allowing the Kefir Grains a revitalization period at least once every few weeks and ideally more often. To revitalize the Kefir Grains, simply place the Kefir Grains in 1-2 cups of animal milk for 24 hours. Once the process is complete, the Kefir Grains can be returned to use with an alternative variety of milk.
This may be technically why...
''Kefiran produced by L. kefiranofaciens is a branched, water-soluble polysaccharide, containing equal amounts of D-glucose and D-galactose. The production of this polysaccharide is stimulated when L. kefiranofaciens grows in co-culture with S. cerevisiae (Cheirsilp et al., 2003).''
Without galactose, one of the monosaccharides present in lactose (a disaccharide glucose-galactose), the structural protein that forms the grains can not be done. When taking apart from the grain, the microorganism complex don't behave the same way and are not able to ferment the substrate properly.
I'm just starting and I will try with honey, which have a 10% galactose. Although not vegan, could work and try with other sources of galactose like beets... (Only they have little content but may be enough for a persistent growth and avoiding decay). Unless the lactose itself is needed in the process, it should work...
Source:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3833126/

While this answer does not explain in detail, which part of the chemical makeup of animal milk is missing in alternative milks, I tend to accept this answer because it simply confirms, that an entirely vegan Kefir is not possible (in the long run). But I am still curious why Kefir is more 'picky' than yeast – which grows well on different kinds of substrates.

@juantopo I'd say it's just the result of how Kefir was "husbanded" over time. Unlike simple yeast cultures, Kefir is a complex mix of many different lactic bacteria and yeast. Different parts of the culture thrive in different source fluids - it's probably quite enough for the Kefir as a whole to "die" when the cultures are no longer properly balanced. For example, lactic bacteria mostly thrive on lactose and in salty environments, while yeasts are more about simpler sugars like sucrose. Since soy milk has no lactose, I expect the yeasts outgrow the bacteria, and you lose the culture.

Yes, they are behaving differently because of the lack of nutrients, including lactose, and possibly because of the presence of other chemicals in soy milk that aren't in dairy.
Kefir grains are a complex community of different types of lactic acid bacteria and yeasts which metabolize (eat) various nutrients/chemicals in their environment. Because soy milk is a chemically different environment than dairy milk, these communities function in different ways. Over repeated propagations in soy milk, you probably have cultivated a very different community in regards to species diversity and the chemical products.
As Liu and Lin describe here
, the kefir community members in dairy milk are eating mainly lactose, whereas in soymilk they are eating sucrose, raffinose and stachyose. As a result, the reproduction of the bacteria and the yeasts differs, as did the alcohol and lactic-acid contents of the end-product.
Because your question is a practical one, you might be interested to know that in that paper, the authors found that adding 1% sucrose (table sugar) or 1% glucose to the soymilk produced an end-product that more closely mimicked that of dairy milk. You could give that a try and see if it improves your kefir growth.

 Liu JR, Lin CW. 2000. Production of kefir from soymilk with or without added glucose, lactose, or sucrose. Journal of Food Science 65: 716–719.

Thank you for your response and the link! I already tried sucrose (assuming that the kefir grains need a substitute for the energy providing lactose) but in the long term it does not seem to work: the growth stops. That is why I rather suppose the kefir grains are lacking some kind of trace element of the dairy milk than the need of a different type of carbohydrate. But I will give the glucose a try …

As you say, the added nutrients may just be a short term solution: when Liu and Lin added sucrose or glucose (or even lactose!) to the soy milk, they got alcohol and acid contents that were much closer to dairy milk kefir, but the community balance was still different: in soy kefir the bacteria:yeast ratio was much higher than in milk. I imagine that this community balance is what's affecting your long-term growth.


text:
High Current (Speed) Transfer Buffer Recipe
Does anyone know an effective buffer mix to use for high current Western transfers?  We are successfully using the vendor's premixed buffer to transfer a wide range of protein sizes to PVDF membranes at 1A/25V for 10 min.  We get great results with the vendor's expensive buffer.
I haven't been able to find a non-proprietary recipe that works.  The best ones we have hold the 25V, but then have a decrease in conductivity (increase in resistance) where they will start at 1A, but drop to 0.4A by the end of the 10 min.  The vendor's buffer seems to hold the high current and results in better transfers.
I don't know if it will be helpful to list all the variations I've tried in detail, but they have revolved around modifying a traditional Towbin buffer plus SDS, more glycine/Tris, or MgCl2.  These were all various suggestions from people around the department, but I haven't found much published evidence for a buffer under these conditions.
I realize 1A (and no I don't mean 1mA) is a lot of current, but the vendor's system works really well.  Any pointers on what I might try/add would be appreciated even if you don't have a worked out protocol.
Edit: Info from the MSDS indicates it has 3 reagents:
Listing of dangerous and non-hazardous components:
Proprietary Reagent K
10-20%
Proprietary Reagent EB II
5-10%
Proprietary Reagent S
1.0-2.5%
7732-18-5 water
50-100%
·
.....
Solvent content:
Organic solvents:
0.0 %
Water:
74.8 %
Solids content:
25.2 %

[I'm not sure if this MSDS info should be put here, just because I'm looking for someone who has already used a high current buffer they know the formulation for, not a guess to what I have.]

I can't help you with respect to wet transfer buffers. If you don't mind using proprietary systems, I highly recommend the iBlot system (Invitrogen). It's a dry transfer, available in nitrocellulose or PVDF membranes, and takes ~7 minutes for a complete transfer. It may seem expensive, but I bet it will save you money in the long run.

@leonardo I believe that even though Life Technologies (gotta keep up with the mergers) would call iBlot a "dry transfer," that it really seems like a semi-dry transfer with very nice pre-packaged cell set up.  I have used them, and the gels certainly seemed wetter than dry.  I feel like Licor as more of a 3-rd party non-player had an interesting analysis.

Yes, Life Tech is now the parent company. ;) The analysis is interesting, but I would conclude from the report that iBlot has similar performance to wet and simi-dry transfer methods. The biggest improvement I've found was the greater resolution and sharpness of bands over manually poured SDS-acrylamide gels.

@leonardo although you get the same resolution/sharpness using precast gels and the standard Towbin's wet transfer method...

@MattDMo  I certainly have plenty of love for a classic Towbin transfer, but I'm in a high western throughput kind of place right now.  I'm doing about 4 gels and 16 blots a day through high-speed solutions (and getting good data), I was just hoping to find a way to bring costs down.

@AtlLED - I understand where you're coming from, I was just trying to clarify leonardo's comment about clarity. FWIW, I used to run at least that many westerns a day: I used Invitrogen precast gels, and did a wet transfer at 100V (constant) for 1hr@4C. One of the issues we found with the iBlot was its transfer efficiency of very small/large proteins - you can get one, or the other, but generally not both.

I would look both into the MSDS sheet and, if any, the patent. They should help you to identify the components but not the recipe.

Already did.  Obscured in propiatry.  Even gave huge ranges in what ever the mistory compounds were.

did anybody see this article ? http://www.sciencedirect.com/science/article/pii/S0003269713003230 I tried it and it works !

So after a lot of work in optimization, I thought I would post what worked best for me.  This buffer recipe was able to successfully transfer EGFR and insulin from the same lysate, and a clear band for both (large and small protein respectively). 10% SDS-PAGE gels were transferred at 1A for 10 min.
High Current Transfer Buffer

48 mM Tris
15 mM HEPPS
1.0 mM EDTA
1.3 mM NaHSO3
1.3 mM N,N-dimethylformamide
25 Mm gLY-GLY
20% Methanol (v/v)

I do hope this can help someone else, and want to site Garic et al as wonderful starting point.  Their publication was made after I asked the question, as @user4148 pointed out.

The SB buffer has been around for quite a while, and I definitely have used it successfully before for both agarose and PAGE gel buffers for some time. The only thing is that you have to run the gel in a cold room (high voltage equals high temperature) and that you have to optimize the timing and conditions so that your samples don't run off the gel.

I've used SB.  First, isn't it a running buffer, not a transfer buffer (or at least I've never heard of it being used in transfer), second I believe the formulation is still some what broad no?

If you look at the running buffer recipe it contains SDS, whereas the transfer buffer contains methanol. Using the same base buffer but adding the different reagent, I have used it before. However, you might have to try it with your specific recipe and running conditions to optimize it.

A recipe with SB buffer for western https://www.mcdb.ucla.edu/Research/Banerjee/protocols/Western-Blotting.pdf

My point wasn't that I couldn't find SB recipes, my point was I could find several.  I will give the linked one a try and see how it stands to optimization.  I still can't find examples of SB in high current low voltage situations (especially for protein transfer).  The one you linked notes 25V o/n, which is the opposite of what I'm trying for.

I am just pointing out that it can be used for transfer buffers as well. But interesting enough people seem to have mixed experiences with it. I think in general you probably don't want to run fast transfers if you are looking for very precise or accurate results because it is generally a trade-off that you need to consider.

Ah but there's the rub, I'm getting both precise and accurate results with the vendor's buffer.  I've compared it directly to an overnight slow tank transfer.

Probably because they have spent lots of time and money optimizing the product. Many of the proprietary recipes and protocols are not more or less complicated, just better optimized I guess...

Yeah I don't think a SB buffer is going to work.  I tried several formulations, and they all fared far worse.  Some even boiled.


text:
Are there animals which can see movements better than shapes or colors?
I remember that in Michael Crichton's novel Jurassic Park, Tyrannosaurus Rex was supposed to have movement based vision. (Of course, that is a novel and not a scientific text.)
I have also noticed while feeding chickens, that they behave differently when they see me adding the food for them into the container as opposed to leaving it there for them when they cannot see me. (But this can be explained easily by different reasons, for example they are used to human as a source of their food, so they naturally go close to them.)
So my question is:
Are there some kinds of animals who have primarily movement based vision? If yes, which animals are examples for this?

The Michael Crichton's novel has been widely discussed online, I found for example this and several answers at Yahoo Answers. Frogs and reptiles are mentioned there.

This is my first post at this site and I am a newbie here. (Not to mention that I am asking just out of interest and I do not have much background in biology. I am not sure, whether you take also questions from amateurs.) I tried to find some reasonable tags, but as I am not that familiar with tagging system here, please improve the tagging if needed. I apologize in advance if the question like this is off-topic here.

Looks like a great question to me and good tag choices. I'm looking forward to reading the answers. +1

@Martin, I also think it is a great question, well written and explained.  No apologies at all necessary! +1

I think "movement-based vision" is perhaps a bit of a misnomer. Ultimately, all vision is contrast-based, depending on integrating signals from ON and OFF bipolar cells. It seems that this notion of so-called "movement-based vision" is derived from work on toad vision and feature detection. In this case, it's more the downstream processing that results in different behavior based on the shape of the stimulus and the direction that it moves. The simple sensing of visual stimuli does not seem to be motion-based.
So, aside from evolutionary inference, we would have no way of knowing whether Tyranassaurus rex had such behavior. As for the chickens, it's possible but I would be skeptical of such a system discriminating between immobile food and hand pouring food. I would chalk that up to a simple behavior of associating seeing you with getting food.
One interesting note: many, many species have reflexive responses to moving visual stimuli. The first is called the optokinetic reflex, in which the eyes reflexively track contrast-based movement; and the second is the optomotor response, in which the head or even the whole body move in response to a moving stimulus. Thus it is safe to say that for many (most?) species, motion detection has a strong influence on the visual response...but again, I remain hesitant to use the phrase "motion-based vision".

Nocturnal owls may present a good example of an animal with greater sensitivity to movement than color. While they also rely heavily on good hearing, many owls like the Scops Owl referenced in the link below (time~ 5m 58s), rely heavily on detecting movement rather than color. Other nocturnal predators that rely on vision, such as many felids (e.g. ocelot), may provide further examples.
http://www.youtube.com/watch?v=ShPhYUQmRN8#t=05m58s

Broken video link :(

There certainly are many adaptations in the light receptors in the eyes that enhance contrast, color sensing, color discrimination as well as feature and movement sensitivity.
In school we usually learn about the cone and rod cells which are color and contrast sensitive in humans.  Humans have only 3 types of cone receptors, the record may be 16 types of cone receptors.  Many animals have no cone receptors and don't see color.  The highly polychromatic mantis shrimp with 16 color receptors mentioned here may devote most of its brain power to motion sensing and little to color or feature parsing.
Motion sensing is not only wired in the brain, but the neural layers within the retina also generate neural signals when motion happens in the eye.  In the case of human beings the rod cells generate motion sensitivity..  Individual cell groups can cue to motion in a specific direction before passing off to the brain, which really helps with the reflex time.
All this takes a lot of brain power and the density of the cone cell density is highest in the center of your field of vision.
The density and the neural structure of the retina is highly flexible, adaptable to many configurations.  Humans have a circular patch of high density cone receptors, cheetah have a long vertical streak of them which help them track prey when running at speeds over 60 miles per hour.
All this being said, its unlikely that an animal would only see movement, especially a larger on. In Jurassic park, the tyrannosaurus motion only eyes was a dramatic twist - its hard to imagine an animal having such a huge blindspot.  Indeed this specific theory is now mostly discounted.

Wikipedia states "Compound eyes are very sensitive to motion." Peripheral vision might also be more sensitive to movement than to shape or color and some animals might have greater emphasis on peripheral vision (e.g., a spider's additional smaller eyes?).

I hate to say it but you said a lot without actually answering the question. The first two paragraphs are irrelevant. The third establishes that yes, organisms can detect movement (not that they have so-called "movement-based vision"). The fourth paragraph is not only irrelevant but the two phrases of the sentence are not even related to each other. The fifth paragraph is irrelevant. The last paragraph says nothing and links to a page that was already linked in the question.

check out the last paragraph now..

Your last paragraph still just uses as its main source a page that was already linked in the question. I'm sorry but it still reads like you just did a web search for vision and threw in whatever interesting bits you found. Anything related to polychromacy is irrelevant and should be removed. In fact, anything related to the photoreceptors without any mention of the bipolar cells is irrelevant and should be removed. Plus there are inconcistencies: you claim that human motion detection comes from the rods but then you talk about the fovea! The fovea imparts visual acuity, not motion detection.

i don't think there is a direct reference that answers this question unambiguously, but feel free to post if you find one.

Even for humans, without saccades we do not have visual perception. Visual system easily adapts to things that do not change. There have been several experiments with human that shows this. Microsaccades are essential. I am busy at a conference now, but if nobody else answers in detail, I'll expand this answer in a couple of weeks with proper references.

Can anybody help me? I don't have the time to find things.


text:
Why not use SDS-PAGE as a method to detect viruses?
Recently, I have been researching about DNA and I know the most popular method for detecting viruses is based on DNA. After learning about proteins, I wonder why we do not detect viruses based on virus proteins?
If it becomes true we can save a lot of money, instead of doing a PCR reaction, we can detect more than one disease in a single reaction.
For example, when I have the sequence of a virus from NCBI Genebank, I can know how many proteins the target organism produces and I can calculate the molecular weight of each protein. Then running it in a SDS-PAGE gel to see what the bands look like, may be that I can know the target organism is present or not?
For example, HIV produces 9 proteins and the molecular weight of each protein is different.
So after doing electrophoresis, I have 9 bands. Based on the distance between each band and based on the molecular weight, it's possible to know HIV is present or not?

Put simply, the answer is that you could seek to detect viral proteins, but because these proteins would be very minor components of your sample, you would have to use an immunoblotting technique to detect a specific viral protein. While immunoblotting is quite a sensitive technique, I think its fair to say that it can be technically demanding. In contrast a PCR reaction is exquisitely sensitive and is fairly robust. PCR is also technically more staightfoward because DNA is generally easier to work with than are proteins.
Before the advent of PCR, immunoblotting would have been the method of choice.

also many viruses will have nearly the same molecular weight and therefore a nearly identical SDS PAGE pattern.

@AlanBoyd point, comment removed.

Absolutely correct.  And to the advantage of "more than one disease" this can, and routinely is done, with qPCR, with a much higher sensitivity that can reasonably be obtained via western or even ELISA (which is a viable detection system often based on protein).


text:
which exact mechanism triggers the first cell differentiation after n divisions?
I would like to understand which mechanism triggers the first cell differentiation after n divisions.
I read previous articles on SE and Wikipedia articles on cellular differentiation and embryogenesis but still fail to understand what exactly makes it so that starting from a given division cells suddenly start to be different.
Wikipedia claims that

In the first hours after fertilization, this cell divides into
  identical cells. In humans, approximately four days after
  fertilization and after several cycles of cell division, these cells
  begin to specialize, forming a hollow sphere of cells, called a
  blastocyst

but do not explain why they begin to specialize.
I could imagine

that a cell has a "counter" on the number of divisions which triggers differentiation after a given amount of divisions
or a chemical substance (either cell-borne or external) forces a change in the division

but why some cells would become "cell A" and some others "cell B"?
I am fairly sure that the biochemical mechanisms which regulate the life of a grown up mechanism can explain cellular differentiation (through hormones for instance) -- I am however interested by this specific moment, this n-th division where identical cells become differentiated.

There are two different questions here. One is how "identical" cells become different types of cells. The other is why do the cells start differentiating when they do.

I am interested in the why more than the how

The why and the how are somewhat inseparable.

The first differentiation in human embryogenesis is from early blastomeres into trophoblast, which forms the outer layer of the blastocyst, and inner cell mass (ICM). It may be unsurprising then that cells on the inside of the 8-16 cell stage morula
differentiate into ICM whereas those on the outside differentiate into trophoblast. However it is currently unclear whether this is a causal relationship (the inside-outside model) or whether blastocyst patterning is set-up earlier in cleavage (such as in the apicobasal polarity model) or if it is some combination of the two.
You were correct in imagining that tissue patterning is determined by chemical substances: a very broad class called morphogens. Cells don't necessarily count how many times they have divided but cell division can certainly affect morphogen concentration and localisation. I suppose in some sense you could describe this as a clock. I wouldn't though, especially because mammalian cleavage is asynchronous.
One line of studies showed that a transcription factor called Tead4 specifies trophoblast$^{ref}$. It was then shown that Tead4 can be regulated by cell-cell contact (mediated by Hippo signalling) $^{ref}$. They hypothesised that the magnitude of cell-cell contact could provide a mechanism by which Tead4 localisation could be controlled in presumptive trophoblast and ICM. This could explain why the cells have different fates because inner cells are completely surrounded (more cell junctions) whereas outer cells are largely exposed to the medium. Note that I only provided that as an example of a possible mechanism. It is not confirmed and, as with any model, the real picture is incredibly more complex and likely involves many factors.
I'm reluctant to go into too much detail on this because you're asking about a complex process that is still under active study and I'm unclear as to how much information you actually want. A book could be written on this subject alone, and many review papers have been published. Here's a recent one:
Development: Do Mouse Embryos Play Dice?
I suggest you read that and then if you have further, more specific questions, we can try and answer them for you.

Thank you for the detailed answer. It looks like a horrendously complicated mechanism (I have a PhD in Physics and the basic ideas can be explained with some hand waving - I was foolishly expecting the same in embryogenesis :)).

I guess the hand wavy explanation would be that tissue patterning is done by chemical signals which can come from a variety of sources. In the case of the first differentiation in human development, the exact mechanism has yet to be fully characterised. It could be that the cells on the inside are in a different environment than the outside cells and so develop differently. Or it could be that the cells that become the inside are already fated for a certain development path.

Also, I sometimes ask basic physics questions and even the hand waving explanations tend to go over my head. For me, hand waving only begs more questions.

Why cells differentiate or specialize is an ephemeral question. I'll make an attempt to answer--the more specialized cells an organism has, the better equipped that organism is to function.
In a given organism, differentiation after n divisions or after t time during development is due to changes that are both intrinsic (genetic) or extrinsic (environmental). For two examples of how intrinsic and extrinsic determinants interact are:
"Unfolding a chordate developmental program, one cell at a time: invariant cell lineages, short-range inductions and evolutionary plasticity in ascidians."
and
"Cell Patterning"
If a cell changes after n divisions at t time, it may be due to its local cellular environment, or in the case of some animals, hormonal regulation that each cell may respond to differently.
As such, why do cell differentiate? Because in organisms, which are large collections of cells, survival is wholly dependent on the segregation of cellular function.

It would be great if you used some references to support your response!

Thanks! I've done that and edited my response accordingly.

Thank you for the answer and the links but I was not really asking why cells differentiate in general but rather what mechanism triggers the first cell differentiation. Possibly in an understandable way (which, per my comment above, seems to be rather difficult)

Richard and Natalie Gordon proposed that there is a mechanically sensitive bistable organelle in the apical ends of cells in cell sheets about to differentiate (competent) and they are under mechanical tension. Depending on where the cell is on the sheet the tension will be resolved by either the apical end contracting or the apical end expanding. This will result in a biomechanical transduction signal from the cytoskeleton that is passed on to the nucleus which then changes gene expression. If the cell has experienced contraction, one signal is sent and it the cell has experienced expansion then another signal is sent. The signal is the determination of cell fate and is done by the cytoskeleton. They have outlined their research and their theory of differentiation waves in detail in their book "Embryogenesis Explained". In your specific example, the first differentiation takes place during mammalian compaction. Cells on the outside expand and become determined to be trophoblast, cells on the inside contract and become determined to be the inner cell mass. All the other stuff, gene expression changes, signalling proteins and the rest are secondary, the result of differentiation after the cytoskeleton determines cell fate with mechanical signals. Note this hypothesis is very detailed and specific, relatively simple overall, and based in mechanics and physics. It is highly testable with no "hand waving". You can read the short version of the theory for free in https://link.springer.com/article/10.1186/s12976-016-0037-2


text:
Are human eyes equally sensitive to AC, and DC lamps?
Definitely anecdotal.
This friend is hypermetropic, and uses reading glasses. He doesn't have major issues facing car headlights, or using a torch (the one with a bulb - not a white LED). Yet place him in front of a TV/Computer screen, and he'll develop an ache in the eye sockets in no time.
I understand an electric torch, an incandescent bulb, a car lamp are all DC types, whereas a TV/Computer screen is fast changing AC.
Are human eyes equally sensitive to light from an AC, and a DC lamp?

Incandescent bulb also can use ac. Tv screens are different case altogether. It is a flickering light.

I'm not great with electronics, but don't all devices use DC? Computers and TVs require AC adaptors to convert the AC power supply to a usable DC signal.

Depends on the device. Many lamps work on AC. Fans and motors work on AC.
Incandescent lamps work on the principle of electrical heating which both types of current can do. Semiconductor devices generally use DC because direction of the current is important. TV screens are not continuous light; it is a kind of flickering light. In a previous post, this has been discussed with respect to cats and dogs. You may find it useful.

@WYSIWYG: The link to the other post was helpful. ty (+:

I doubt that it's what kind of electricity provides the power -- rather what wavelengths of the light are emitted.

Let's not confuse the type of power of a light emitting device with the type of light it produces.
This question is not about AC or DC current. It is about flicker frequency, light wavelength and their biological effects.
Flicker frequency
The term "ache in the eye sockets" probably refers to asthenopia.
Human eye cannot detect flicker with a frequeny above 75 Hz. But many computer displays have a refresh rate of 60 Hz [1]. Out of focus and  low refresh rate monitors are known to cause eye strain and asthenopia [2], favored by existing hypermetropia (and other vision issues).

Visual discomfort has been related to 1) the presence of flicker; the possibility to regulate, 2) brightness, 3) height; and 4) inclination of monitor. Asthenopia has resulted statistically correlated to the presence of flicker and to the impossibility of regulating height and inclination of monitor for both sexes. The possibility to regulate monitor brightness has not determined a reduction of visual discomfort either in men or in women [3].

Wavelength
Eye sensitivity is different (see spectral sensitivity):
"Cones SMJ2 E" by Vanessaezekowitz at en.wikipedia / Later version uploaded by BenRG. - Based on Dicklyon's PNG version, itself based on data from Stockman, MacLeod & Johnson (1993) Journal of the Optical Society of America A, 10, 2491-2521d http://psy.ucsd.edu/~dmacleod/publications/61StockmanMacLeodJohnson1993.pdf (log E human cone response, via http://www.cvrl.org/database/text/cones/smj2.htm)
Transferred from en.wikipedia to Commons by User:Richard001 using CommonsHelper.. Licensed under CC BY-SA 3.0 via Wikimedia Commons.
Light color and color contrast matter:

The study results showed that both visual acuity and the subjective visual fatigue were significantly affected by the color of light [4].
Images with excessive energy at medium spatial frequencies (Fernandez and Wilkins, 2008 Perception 37 1098-1113), or that have high color contrast and little or no luminance contrast (Wilkins et al, 2008 Perception 37 Supplement, 144-145) appear uncomfortable or aversive and can induce headaches in hypersensitive observers. Such stimuli are uncharacteristic of natural images [...] [5].

Blue light can also reduce melatonin levels and affect sleep and mood (the studies don't have a strong conclusion though):

Melatonin concentrations after exposure to the blue-light goggle experimental condition were significantly reduced compared to the dark control and to the computer monitor only conditions. Although not statistically significant, the mean melatonin concentration after exposure to the computer monitor only was reduced slightly relative to the dark control condition [6].
All light is not equal: blue wavelengths are the most potent portion of the visible electromagnetic spectrum for circadian regulation. [...] evening use of amber lenses to block blue light might affect sleep quality. Mood is also affected by light and sleep; [...] At the end of the study, the amber lens group experienced significant (p < .001) improvement in sleep quality relative to the control group and positive affect (p = .005). Mood also improved significantly relative to controls [7].

References:

Wikipedia contributors, "Flicker fusion threshold," Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Flicker_fusion_threshold&oldid=615159751 (accessed July 29, 2014).
Wikipedia contributors, "Asthenopia," Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Asthenopia&oldid=617227613 (accessed July 29, 2014).
Rechichi C, Scullica L. [Asthenopia and monitor characteristics]. J Fr Ophtalmol. 1991;13(8-9):456-60. PubMed PMID: 2081858.
Lin CJ, Feng WY, Chao CJ, Tseng FY. Effects of VDT workstation lighting conditions on operator visual workload. Ind Health. 2008 Apr;46(2):105-11. PubMed PMID: 18413962.
Juricevic I, Land L, Wilkins A, Webster MA. Visual discomfort and natural image statistics. Perception. 2010;39(7):884-99. PubMed PMID: 20842966.
Figueiro MG, Wood B, Plitnick B, Rea MS. The impact of light from computer monitors on melatonin levels in college students. Neuro Endocrinol. Lett. 2011;32(2):158-63. PubMed PMID: 21552190.
Burkhart K, Phelps JR. Amber lenses to block blue light and improve sleep: a randomized trial. Chronobiol. Int. 2009 Dec;26(8):1602-12. doi: 10.3109/07420520903523719. PubMed PMID: 20030543.


text:
Can Squirrels Eat Every Mushroom?
Squirrels have the ability to eat toxic mushrooms as described below. Are there any mushrooms that they can't eat without dying?

According to Dr. John Rippon, an IMA member and world expert on fungal diseases, squirrels have an interesting adaptation that allows them to eat mushrooms containing deadly amanita-toxins without being affected. There are three important chemicals in the amanitas. Two will knock you right off, but are destroyed in cooking. The third one is the interesting one: it consists of the second amanitin, bound tightly to a glycoprotein molecule. When we digest the mushroom, the enzymes in our gut break the bond between the toxin and the glycoprotein, leaving the toxin free to enter our bloodstream, while the glycoprotein is excreted (a glycoprotein is a [protein containing sugar molecules and accounts for the viscous properties of mucus], in case you don't know). What the squirrels have done is line their gut with a toxin-compatible glycoprotein, so that as soon as it gets split from its original glycoprotein molecule, it gets rebound to the squirrel glycoprotein, and excreted along with it. Obviously, the squirrels don't cook their food to destroy the first two molecules, but presumably those get bound in exactly the same way. Thus, squirrels and a few other animals (guinea pigs also, I believe) can eat mushrooms that are highly toxic to other animals with no ill effects.  Source

I don't know the answer to the question, but just a quick correction: a glycoprotein is a protein with a small sugar attached, not a "mucus molecule".

from doing a bit of research, I think I can say that as of now there is no proof for the same.