Salting and its effect on cellular material
Submitted by Yoshan Moodley on 05/15/2003. (
moodleyy@cardiff.ac.uk ) 131.251.29.225
Dear Taxidermists
I have been prompted to add this to the Taxidermy.net forum. I am sure that most of you are aware of most of this, but please read further if you think that this may be of interest to you.
When an animal is skinned and fleshed in the field, the best way to preserve its skin is to liberally apply rough salt (Sodium Chloride) to it and leave it to dry. Salt acts as a dehydrator and absorbs moisture (or cytosolic fluid) from the skin (epithelial) cells, markedly speeding up the drying process. It this rapid dehydration of cytosolic fluid that enables the epithelial skin cells to retain much of their intracellular organelles such as nuclei and mitochondria. If skin was simply left out to dry in the sun without the application of salt, then there would be enough time for the degradation of cellular material by proteases and lysozymes housed within the cell. If, on the other hand, the skin dried quickly enough to beat this degradation, the heat required to dry it this quickly would end up causing a similar amount of organelle and structural (cytoskeletal) damage. So, you see, there is no getting away from it, salting is the best way to preserve skins in the field. The quality of salt used may sometimes cause problems with the quality of the skins after tanning and it is always important that your clients make sure that the salt they use is first grade.
From a DNA perspective, dry-salted skin harbours a gold mine of epithelial skin cells, each with more or less intact nuclei and mitochondria - the two organelles that harbour all our DNA. This is why we require only a small piece of skin for DNA studies. When we receive the skin piece we incubate it in an isotonic solution with 1% sodium dodecyl sulphate (SDS) and about 200ug/ml of proteinase. SDS is a powerful detergent which lyses the cell membrane which is made of fats or lipids. Then the proteinase chomps up the proteins of the cell indiscriminately, releasing the DNA molecules from the nucleus and mitochondria. We then apply phenol to get rid of the protein debris and separate these from the aqueous liquid which should by now contain just the DNA in solution. It is as simple as that!
Every now and then we receive pieces of skin from animals that have died in the veld and have decomposed naturally. The hard skin, with cells completely degraded, may still house DNA, but without the protection of the cytoskeleton and the nucleus, this DNA has been broken up into very small pieces by the action of UV radiation from the sun. Luckily technology is of such a standard these days that we can even make use of this degraded DNA in genetics, although much more effort must be applied in order to get these samples to work in the lab.
The most tragic element of taxidermy and museum curation is the tanning of skins. When this happens, the cellular and biological elements of the epithelial cells are replaced by chemical ones. The skin is virtually DNA free and is useless for any genetic or forensic investigations. It is unfortunate that tanned skins look and feel so much nicer than dry-salted ones and I do not blame taxidermists one bit for preferring to work with skins in this form.
I thank you for reading through this and hope that it has been of some help.
Sincerely
Yoshan Moodley
Cardiff University
Wales
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Thank you, Yoshan!
This response submitted by Glen Conley on 05/15/2003. (
g.conley@verizon.net ) 67.241.79.38
See Yoshan's request for help in obtaining bushbuck skin samples in an earlier post.
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YOSAN
This response submitted by ETCC on 05/16/2003. (
getrichkwik@webtv.net ) 209.240.198.61
Thank you kindly for educating the unknowledgeable masses.
Yep...SALT...is the cheapest product used in taxidermy. Sad paert is...many 'don't get it'.
~ ETCC
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Great post, Yoshan
This response submitted by George on 05/16/2003. (
georoof@aol.com ) 205.188.209.8
Between you and Glen, I'm learning things I thought impossible for the mentally impaired like myself. LOL. Great post.
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Salt dry skins/hides
This response submitted by Glen Conley on 05/16/2003. (
g.conley@verizon.net ) 65.227.21.74
This post is too good to leave alone. To further help focus thought
processes, here is my quote that I had posted under Yoshan's request
for bushbuck skin samples.
"Research work of this nature always has great implications. As often
as not, the data garnered can have a trickle down effect in other
industries."
Already, right up front, we have already reaped the benefit of knowledge from a research project that is only at the beginning
level.
Yoshan's writing style displays great humility and respect for the
intellectual capacity of fellow man.
Intellect is not even an issue here. If any thing should be considered an issue, it would be lack of exposures or education,
and I do not say this in a derogatory fashion. It is no secret, educational opportunities and exposures vary terrifically in different geographical sections of this country, always has, and with the advances in technology applications, such as this Forum, "catch up" can be done.
I need to point out at this time, the years in which an individual attended school has a great bearing on what they know as an adult.
For examples, the Hydrogen Bond Theory was introduced in high school
chemistry classes in this state, and many others, in l964. That was a
very heated topic of debate amongst educators at that time. It appears as if the Hydrogen Bond Theory has moved from "Theory" to "Principle" today. It's still around, and many advancements have been made as a result of. The discovery of the double helix structure of DNA by Watson and Crick was also made in 1964 and was in college bio text by 1967.
The toughest homework assignment I ever had, circa '67 (yep, I'm an old dude), was the conversion of radiant sun light energy into a utilizable form of energy via the photosynthesis process. I could not figure out the last equations, I was such a dumb kid. We all turn in our papers, with no final answer. And guess what? We didn't get an answer after the fact. But now, a simple chart is available to explain this away. I would have never thought to convert water and carbon dioxide into the molecular chain we know as dextrin.
With the chronological dates I have pointed out, each can gain a perspective point for their own life. It may well be the individual did not sleep through that part of the class, but simply the fact that the information may well not have been available at the time.
I was so excited over Yoshan sharing information that I over looked the fact that many would not be able to utilize the information because of not knowing the language.
Proteases and lysozymes are enzymes. These were referred to as housed
within the cell. We are all aware of enzymes, even if we do not
recognize them by name. These enzymes were already present within the
living cell, so you can see, they are already "in place" and can start
decompositions immediately upon death. Not only can the enzyme lysozyme destruct it's own cell, it can destroy bacteria. Hmmmmm.
I have noticed confusion and uncertainity in the past in regards to skin structure. Skin is NOT totally cellular in structure, but the cellular layers are supported by fibrous collagen structures, which is of great interest to us in tanning and taxidermy. At this point, only cellular structure has been addressed. One must look at the skin as a whole for a better understanding.
To take a look at a hair follicle, you will see that it is embedded in the cellular structure portion of the skin. The hair is already "set" in a healthy skin. Dry salting simply prevents the destruction of the surrounding cellular structures, but so does Borax.
I have posted on here in the past in regards tobacterial decomposition, but to recap:
First off, the bacteria has to have a source. They can already be present, or even be airborne. As with a disease, an incubation period is needed for numbers to reproduce to the point that the sheer volume of numbers causes rapid destruction. In order to feed, the bacteria must release an enzyme to break down larger structures into small enough structures that can be taken in through regulatory "valves". The by-product of bacterial digestion will be an acid, this acid can be viewed as a two fold function for the existing bacteria. One, the acid will also start breaking down larger and more complex structures into simpler form.
Two: The acid can also interfere with synthesis of competing micro-organisms.
I should point out at this time that salt also "draws" acids because of opposite charges.
Not only enzymes, but bacteria too have to have a SUITABLE medium (liquid)through which to travel. Now how about we throw in another enzyme source, say enzymes found in extracellular fluid, and maybe even cover the effects of enzyme activity as influenced by temeperature? Freezing on one end and optimum temperatures on the other?
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Intellect
This response submitted by rickettchade wabbit on 05/16/2003. ( ) 199.183.196.244
Intellect in here? or is that an Italian Name?
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GLEN
This response submitted by ETCC on 05/17/2003. (
getrichkwik@webtv.net ) 209.240.198.61
Err...bean kinna Blonde-like...kin ya repeat whatcha said after...
"This post is too good to leave alone".
~ ETCC
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Sure, ETCC!
This response submitted by Glen on 05/17/2003. ( ) 65.227.21.88
That helps to make my case in point! I'm an old dog that has just recently learned how to use a computer, never had it in school.
By using my new found knowledge, I did multiple copy and paste applications of the section you requested (you didn't say how many times you wanted it repeated), and then e-mailed them to you.
Nothin' to it! Glad to be of assistance.
Glen
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GLEN
This response submitted by ETCC on 05/17/2003. (
getrichkwik@webtv.net ) 209.240.198.61
THANKS Glen!...Ya overlodid me incomin box an I mist a lotta good porn stuff I wuz expectin...dadblammit!
~ ETCC
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Salting and preservation - sodium fluorosilicate
This response submitted by Woody on 07/23/2003. ( ) 216.226.210.98
The following additional information may be of interest with respect to preserving mammal skins.
The late Dr Reay Smithers (author of several scholarly books on African mammals) established the museum system in Zimbabwe, and carried out considerable collecting of vertebrates especially mammals in the region from the late 1940s to the late 1970s. Quite possibly his greatest efforts were devoted to Botswana Mammal Survey through the 1960s. This exploration of a virtually unknown fauna (especially the small mammals) faced special challenges not just with logistics, but equally to cope with sound preservation of scientific specimens. Not least in the many problems was the challenge of protecting mammal skins from insect attack whilst in the field for weeks and sometimes months at a time. Dermestid beetles and certain moths can rapidly damage skins, especially if they or their eggs are packed with salted skins!
Reay solved the problem working with the taxidermists in the organization at that time, notably Terence Coffin-Grey. They proved that addition of sodium fluorsilicate (or sodium silicofluoride) to the skinning powders proved invaluable to halt insect damage. This was for both whole study skins (birds as well as mammals) and to the fine salt (sodium chloride) treatment of large mammal skins - as Yoshan correctly emphasizes. When skins of medium and large specimens were preserved, these were soaked from 30 mins to overnight (depending on size) in a solution of 3lbs Sodium fluorosilicate in 10 gallons water. An important reason for this care with preservation against insect damage in the Botswana Mammal Survey was the quarantine of some material for 3 months against FMD. Skins were salted afterwards (using No 1 fine dairy salt) and then folded into a convenient size - skin side outmost - and then dried. Nonetheless, long term preservation of such skins requires that they be tanned (in the museum); otherwise micrbial attack will destroy them.
Small mammals were prepared as whole, stuffed study skins and preserved with Borax (8ibs); sodium fluorosilicate (1 lb); Magnesium carbonate (7lb) and creosote (4 tablespoons).
This use of sodium fluorosilicate is not widely known, perhaps because it has not been published (at least to my knowledge) except in Reay Smithers' (1971) Mammals of Botswana (National Museums and Monuments of Rhodesia Memoir No 1). this is still the definitive scientific work on the mammal fauna of the territory, but unfortunately now a scarce book. We in the mammal department continue to use this tried and tested formula!
A lasting monument to Reay Smither's efforts is the remarkable quality of the dry skins preserved in the Mammal Collection here at the Natural History Museum of Zimbabwe in Bulawayo. Professional preservation in the field at collection played a major role in this.
Incidentally, the scientific collection of extant mammals (approx 100 000 specimens) in Bulawayo is the largest in the southern hemisphere and among the 8 largest in the world (along those in American Museum of Natural History, London, Smithsonian, ROM in Toronto etc). The bulk of the specimens here are from south-central Africa, especially Botswana, Malawi, Mozambique, Zambia and Zimbabwe.
sincerely
Woody Cotterill
Principal Curator, Department of Mammals, Natural History Museum of Zimbabwe, Bulawayo
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WATER AIN'T WATER!
Submitted by Glen Conley on 12/23/2002. (
g.conley@verizon.net ) 63.26.248.211
Water is known as a universal solvent.
Any one here ever fish with soft craws? Some know them as crawdads, some as crayfish, some as crabs, some as all the preceeding. Before the soft craw is soft, he is hard. Now the way he gets soft is by systemically absorbing a good part of the calcium in his existing "shell" (ectoskeleton if you prefer the term) that he has out grown. Once the old "shell" is sufficiently softened, the craw can push out, or shed. This is when you want to gather them for bait. You take them home, put them in the fridge, and cover with a damp cloth or paper towels or damp Sphagnum moss.
Any one here ever buy an African violet, take it home water it and watch it shrivel up and die?
Any one here ever get water spots on their dishes?
Any one here ever have a water heater "lime up"?
Any one here ever buy a fish that was truly tropical rain forest in origin that "slimed up" and died?
Not too many people have missed out on aquarium keeping, so let's keep this one on a roll.
Any one ever buy an Amazon sword plant, bring it home, plant it and watch it turn all brown and spindly?
Any one ever have female fish fill with spawn and stay that way even with males in the tank?
Any one ever have females spawn out, males fertilize and eggs still not hatch?
Or perhaps eggs did hatch and fry survived but they were predominantely of one sex?
Any one ever wonder what all that gritty stuff was at the bottom of a pickle bucket?
All the above questions have a common denominator involved. Now I'm going to reverse the denominator.
Any one ever buy African cichlids of Rift Lake descent (Malawi, Victoria, Tanganyika) and put them in "soft" water to watch them grow lethargic, thin and die?
The common player in all the above is calcium carbonate, or in simplest terms, dissolved rock. Hard water. Remember the carbonate word, I'm coming back to it.
When the craw was taken from the water, he was removed from a source of calcium carbonate to restructure his "shell". The available calcium in his system will harden his shell to a degree and produce a "paper" craw, if he lives that long. So I don't appear sexist, the same would hold true of female craws.
African violet, remember that carbonate word. Amazon sword plant, you know the drill, carbonate word.
Spots on dishes, a visual, pure water evaporates and leaves what as a residue?
Limed up water heater, another annoying visual, indicating an abundance of calcium carbonate, if elements are being replaced frequently.
Tropical fish sliming up (if they lived long enough for you to see this happen), a condition known as alkaliosis. Caused by? You're going to get a big fat F if you don't get this one right.
The spawn filled fish that don't spawn is probably due to calcification of eggs near the vent. Eggs laid and attempted fertilization by the male with out a hatch is along similar lines as the craw that needed the calcium carbonate to harden his shell. The difference being, the shells hardened before the sperm could make union. Speaking of sperm, the same sex hatch phenomena for years has been associated with pH levels of the water. pH and hardness can ALMOST go hand in hand. We violate this part in our acid pickle practices. The gritty stuff in the bottom of the pickle bucket? We wouldn't have a calcium precipitate there, would we? Calcium precipitate!?! Where's that carbonate word? It's gone. Sorry.
The African cichlids died from a lack of calcium carbonate in the water. They had evolved over the eons in water not a whole lot unlike the water we have in a good part of this country. The sliming up that goes along with both acidiosis and alkaliosis is a quick fix attempt by the fish to regulate the loss or gain of fluids. In many cases, a fish may be able to adapt it's body in a three day period. In many cases, depending on species and origin, it may not.
Notice that for the greater part I used living examples for all of the above. I did that to illustrate as to how little it can take to make a big difference in end results, in those cases above, it is literally a life and death situation.
Water hardness is measured in German degrees hardness or in parts per million. Let me repeat that, PARTS PER MILLION. The creeks, lakes, rivers and ponds in this neck of the woods will consistently test 750 to 850 parts per million total hardness year around, with pHs of 7.8 to 8.2. Shallow wells will frequently show similar readings (60 feet or less). Deep wells in the aqua fir may well be quite higher, but yet another deep well may yield readings of almost half the hardness.
The readings I just described will bring on all the conditions that I had described above.
If you were to use litmus, or hydrion papers on a baking soda solution in distilled water, you will show a reading of 8+ on the pH scale. This solution is called a sodium bicarbonate solution. There's that carbonate word again. Acids aren't picky when it comes to reacting with a compound containing a carbonate. They will react with the calcium carbonate in hard water just as quickly (for all practical purposes to any one wanting to throw molecular weights into the quo) as the baking soda solution you buffer or neutralize with. The milder acids will be neutralized quicker than the "hotter" acids simply because the concentration of the acids is less requiring a lesser concentration of carbonates.
The plant examples above responded in a negative fashion because they needed slightly acidic conditions. Water your African violets with rain water or distilled water. Grow your Amazon swords in rain water. The hard water neutralized the acid conditions they needed.
The hint for the day to either the beginner thinking of tanning, but now half scared to do so, or to any one who suspicions water as a source of problems, buy distilled water for your acid pickle. That will eliminate the "tricky" variables that can occur with ground water sources. I have yet to talk to a taxidermist that was having tanning problems that knew what their water hardness was. Another simple fix. General and carbonate hardness kits can be purchased for a few bucks through a number of on-line companies or through pet shops. They are manufactured by Aquarium Pharmaceuticals, use that for your search phrase on any major search engine and you will find a buying source.
If you are using well water and getting inconsistent results you now have the technology to monitor the rises and falls of hardness that is not uncommon with well water.
Of dead minnows and bacteria in well water. Assuming the minnows were not given a thermal shock from a temperature difference when placed into the water, I might point out that well water is typically pretty well devoid of dissolved oxygen. That's why aerators are put on faucets, some water will have a "flat" taste if not aerated. Anaerobic bacteria do not require oxygen. They're the ones that eat your poop in the septic tank. I'd worry.
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Soft craws...eh?
This response submitted by Doug on 12/23/2002. ( ) 64.18.238.246
Glen,
What's your location? I haven't heard the term "soft craws" since I was a kid in southern Ohio (Dayton). Up here in Michigan everyone calls them "crabs!" Very interesting reading Glen, and I know enough to know you know your stuff(lol). Merry Christmas!
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Limnology
This response submitted by Old Fart on 12/23/2002. ( ) 64.122.57.23
That was the short course in Limnology. Well written, Glen. Any one interested in learning more should find a book on Limnology, but you had better be up on your Chemistry.
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water hardness
This response submitted by Bill on 12/23/2002. ( ) 216.130.156.53
The hardness of your water will be reported in grains per gallon, milligrams per liter (mg/l) or parts per million (ppm). One grain of hardness equals 17.1 mg/l or ppm of hardness.
The Environmental Protection Agency (EPA) establishes standards for drinking water which fall into two categories -- Primary Standards and Secondary Standards.
Primary Standards are based on health considerations and Secondary Standards are based on taste, odor, color, corrosivity, foaming, and staining properties of water. There is no Primary or Secondary standard for water hardness. Water hardness is classified by the U.S. Department of Interior and the Water Quality Association as follows:
Classification mg/l or ppm grains/gal
Soft 0 - 17.1 0 - 1
Slightly hard 17.1 - 60 1 - 3.5
Moderately hard 60 - 120 3.5 - 7.0
Hard 120 - 180 7.0 - 10.5
Very Hard 180 & over 10.5 & over
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WATER.
This response submitted by SAMW on 12/23/2002. ( ) 64.41.45.232
gLEN THANK YOU FOR ENLIGHTING US .with the sacrmento volume 1 operators manuel.lol I;m going to agree with you also. Ph factors will vary as the aquifer levels rise which obviously you know why.
Agrees also that if people are scared to use there own well water Buy distilled.lol i;m giveing Glen his A-1 opperators license. have a good day.
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This is one....
This response submitted by Mark on 12/23/2002. ( ) 67.217.44.188
This is one of those posts you might just read in "The Best of the Forums" in the next issue of BREAKTHOUGH Magazine.
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wow , ausome , incredible
This response submitted by jen on 12/23/2002. ( ) 64.12.96.79
this post deserves a high 5! excellent debates occuring due to water differences are clearly posted right here
thanks glen , keep up the good work
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Health risks?
This response submitted by Superpig on 12/23/2002. ( ) 205.188.209.144
We live on the edge of the Edwards Plateau region in Central Texas. Our well water (we have a shallow well of about 39 feet)falls into the extreme hard category of over 180. Now I am consuming quite a bit of this water as that is all I drink (about a gallon a day). What,if you know, health risks are involved in drinking extreme hard water? If it affects the plants and fish you would expect it to effect the human body. That is one queston I like to have answered. Any studies done on human consumption of very hard water and it's effect on the human body?
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Lady Evelyn
This response submitted by Glen Conley on 12/24/2002. (
g.conley@verizon.net ) 63.26.248.148
In the chart Bill provided you will see that the Primary Standard does not recognize hardness as a health concern. Your question is still a good one, none the less, and you are not the first to question. Questions are wise, as long as conclusions are not jumped to prematurely, before all the data is gathered or examined.
If you were to start digging around looking for the end results of work previously done by others, in regards to the negative affect of water hardness on human health, you would probably turn up little or nothing. Inconsequential data is most generally deleted from the files. By the same token, you might well be surprised at the amount of positive results your research will turn up. Didn't Old Fart already tell you that you should get a book on Limnology? Once you start digging into this research project, you will find that calcium carbonate is a big player in life cycles,agricultural, manufacturing, and the building industries, but will trace back to it's water
"roots".
It was my intent in my original post to make in-house tanners aware of the carbonate factor in their water supply. No one seems to correlate an already present source of carbonate as a potential problem, and it isn't one coming out of the tap, it occurs when the carbonate compounds are reacted in an aqueous ACID solution OR in an aqueous solution with heat.
When you dissolve sal soda, sodium carbonate, and subject it to heat, you convert the sal soda to sodium hydroxide, caustic soda. I can not remember the exact temperature at which carbon dioxide and water are driven off allowing the sodium to bond with an oxygen and hydrogen (or does the sodium retain an oxygen from the carbonate?), but it is 130 odd degrees F., 140 degrees to be sure. That's why you don't need to boil skulls, only simmer.
The above description is a first step in producing aqua destillate. A more "purified" form of water can be produced by heating to break the carbon bonds, allowing the heavier precipitates to sink. This is in essence what you have already done with a water heater that is set above 140 degrees F. You can check the end results of what you get for carbonate hardness with the kit I described above.
I want to point out again that water is a universal solvent. Naturally occuring trace elements and minerals other than calcium carbonate will be found in any water supply. I think you will also find these other elements in abundance when you get into extreme hard water conditions. A couple of years ago I tested the well water of a taxidermist just north of me. He sits over a HUGE aqua fir and has a deep well. His well had the hardest readings I have ever personally taken. There are a lot of people tapped into this same aqua fir. We did some note comparison on the incidence of submandibular salivary gland stones in the people that we personally knew and it did not take us long to figure out that this had to be well above national averages. Food for thought. If this sounds like an area of suspect, place telephone calls to the dentists in your area to find out how many cases of salivary gland stones they treat per year.
This web site address will either help to ease your mind, or get you started on a course of action:
http://www.niddk.gov/health/urolog/pubs/stonadul/stonadul.htm Doug, my location is less than fifty miles west of Dayton, just the other side of the border. You weren't insinuating that I was writing in a colloquial form were you, eh? Those soft craws are a versatile bait, they can catch shovelheads in Ohio and Flatheads in Indiana.
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