BIOLOGY.HTM

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Biology Projects

It may appear that many of the following experiments have been completed already. However, in most cases, only a small part of the total potential has been explored. If interested in any of these projects, or if you wish to submit more of your own, go to the Registration Page.

BACTERIOLOGY
(See the pages on Micro-Organisms for Education

GUARD-DOG BACTERIA (Pro-Biotics) Perhaps a new realm of immunology that spans both the animal and plant kingdoms. It is the use of various types of bacteria by a host eukaryote to kill other types of invading microbes, including both bacteria and fungi.

Why are there so many "dairy bacteria" in MILK? Are they of benefit to the baby? Perhaps, more importantly, are they of benefit to the mother? How is that they get from the mother's gastrointestinal tract and into her milk ducts in huge numbers within hours? This is a very hot project that is highly likely to be accepted for international presentation in professional society conventions.
What are the "dairy bacteria" doing inside of LEAVES? Are they protecting the tender and moist spongy cells from invasion from environmental microbes that might waft through the pores (stomata) and into the interior air spaces? This also is a very hot project that is highly likely to be accepted for international presentation in professional society conventions.

CANAVANINE(CAN) is an analog of arginine (ARG)

CAN increases ultraviolet sensitivity in E.coli and Yeast. Because CAN is an analog of arginine, and is incorporated into proteins that are inactive "junk". This data supports the notion that UV-damaged cells may have poor abilities to scavenge the junk. Students from the U.S. Virgin Islands and Virginia found that UV was far more able to kill E.coli and baker's yeast when those organisms were grown in 0.4% CAN. (Jaughna-VI, Diane-VI and Alice-VA)
Phage infection was not seen to be affected by the presence of CAN. (Alice-VA)
This work has many other possibilities including the use of CAN on HeLa cells versus normal cells, and then with viral infection of those cells.
The biochemical basis for why insects are so sensitive to CAN? Legumes probably have high CAN levels to protect themselves from insect foraging.

CETAVLON (CET) is an effective antimicrobial agent (bactericide and fungicide) Many shampoos contain NNNN-trimethyl-hexadecyl ammonium bromide under various trade names.

It holds tremendous promise for use as an antiseptic in disaster areas as well as in remote areas of the world . (Erin-TX (state-level), Paras-CA, Megan-(W&M)VA)
Bacterial Spores. While it has been shown to rapidly kill non-sporeforming bacteria, testing needs to be done of sporeforming bacteria such as Bacillus and Clostridium. (Erin-TX)
Does it work against other non-microbial infection agents? Work now needs to be done on its abilities to kill insect and worm eggs, larvae, and other higher pathogens.
Cetavlon effects on chloroplasts is important to know if the compound becomes much more widely used as an antiseptic. Is CET too toxic to put out into the world? Since chloroplasts and mitochrondria are not unlike bacteria in many ways, it would be expected that these organelles would be sensitive to this cationic detergent. The question is: what is the lowest concentration of CET that inhibits chloroplast function? Your AP Biology lab manual has the protocol for measuring chloroplast function using blue DPIP as an electron trap, that becomes colorless.
Ulcers.Since most stomach ulcers are bacterial infections, and since the lumen of the stomach is technically outside the body, the question arises as to whether CET, or similar cationic detergent, might be effective against Helicobacter spp. (Jessica-VA)
Biodegradability. Being such a potent antibacterial agent, will its use lead to a build up in the environment with the consequence of causing great damage to the microbial world upon which all other life-forms depend?

Temperature Effects on the OUTER LAYERS OF BACTERIA. Study of the outer layers of bacteria has two facets: they are the antigens from which antibacterial vaccines are made; and they are the armor that bacteria have as defense against white blood cell phagocytosis and serum complement killing.

Fever inhibits the formation of the LPS outer layer in Gram-negative bacteria allowing normal serum complement to perforate and kill the bacteria. This was presented at the annual meeting of the Amer. Soc. for Microbiology in 1994 by students from California and Virginia. This was the first ever biochemically based explanation as to how fever works. (Iva-VA (made the first discovery as an 8th grader)).
LPS-specific phages. Can the effect of Fever temperatures be demonstrated using LPS-specific phages on these bacteria. This would be an important point to "nail down" that the surfaces are being altered in a major way.
Thermal shifts. How fast do the bacteria change from being LPS deficient to LPS total upon instantaneous changes in temperature? "Loss" of LPS occurs on up-shitt of temperature, and LPS must return upon lowering the temperature.
SDS mimics fever in preventing the formation of bacterial LPS layers. This was presented at the annual meeting of the Amer. Soc. for Microbiology in 1995 by students from California and Virginia.
Fever increases the sensitivity of Gram-positive bacteria to penicillin. (Jeet-CA, Nicholas-VA and reached regionals.) For more, see
Finding out how fever can control Gram-positive infections.
Effect of fever on antibiotic potency.The field is wide open for exploring whether or not administration of antibiotics is best done under fever or normal conditions.
Growing Gram-negative bacteria at less than 22c increases the amount of LPS. This serendipidous finding quickly led to greatly improved typhoid vaccine, which is now saving approx. 8,700 additional lives per year for each of the 50 students in a class that used this as a project. (Unpublished because this sort of work cannot ethically await publication with so many people dying of these diseases!) This can be extended to the possible development of cholera and dysentery vaccines.
Hybernation. If fever is used by our bodies to protect us from infection, and if homethermy is also used for this reason. what happens to hybernating animals with their lower body temperatures. It is often thought that bears die in hybernation because they have not eaten enough the previous summer. Might not it be from an infection?

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Dental Bacteriology.

The normal bacterial flora of mouths regarding tooth decay. Is it the oral bacteria or the food that is consumed that are the primary culprits to tooth decay? (Aubrey-TX)
Needs workers who have mouths of other animals available.
- Aubrey can use her goats, which she raises.
- Of particular interest would be mammals which normally consume sugar cane or sugar beets.
- Primative humans
- Chimpanzees and Gorillas
Paleoanthropological indicators of dental caries

"Guard-Dog" Bacteria: Are the lactic acid bacteria potent killers of other bacteria? These bacteria are common in dairy products, are found coating the membranes of the opening of most animals, and cover most of plants. What are they doing there that disallows the growth of some many environmental bacteria? (Jessica-VA needs a lot collaborators to test many other types of bacteria; Eron-VI, Sally-W&M).

The normal bacteria of the mouth. With the clan of "Guard Dogs" are undoubtedly those inhabiting the mouth. Why don't they protect us from tooth decay? What goes wrong? Is it the bacteria or is it the food we eat. (Aubrey-TX)

A vaccine delivery device with no moving parts. The ideal vaccine delivery device should have many characteristics: costs less than 3㎎S, small, has no moving parts, can only be used once and then self-destructs, and the device and its vaccine would be able to withstand extremes in temperature and humidity for months. Invention of such a device would save millions of lives. See a project in Chemistry concerned with making the stabilized vaccine.

Fecal Polution of the Oceans.How far can the fecal bacteria in sea water travel from cities that don't treat their sewage? How fast do E.coli die in seawater? What kills them - the salinity or the plankton? If it is the plankton, then waters from around the world could be tested as the plankton differ with climates. Caribbean, Atlantic, Pacific, Atolls in tropical lagoons (think Kwajalein H.S., Marshall Islands), and the Arctic (think: Pt. Barrow H.S.). Mindy-VA, Clayton-VA

E.coli as a soil bacterium. World sanitation standards for fecal pollution of surface waters depends on whether or not the intestinal bacterium E. coli is found in the water sample. Recently, E. coli have been found in rain runoff from the top of Oahu (Hawaii) and on other tropical locations that have no human habitation. It thus appears that in certain places in the tropics E. coli grows in the soil alongside all the other common "soil bacteria." How widespread is this phenomenon? Will this mean that sanitation tests will have to be rewritten for the tropical places on earth? This is a project well suited for collaborating students from around the world to test soil samples for E. coli, and then merge their findings into a comprehensive report.

Ants wear Guard Dog Bacteria. A bane of microbiologists is the wandering small ant out on the hunt for food. Far too often the ant finds a petr plate with some delicious agar medium in it. By the next day there are small colonies of imported bacteria growing in the tracks the ant made the previous day. Interestingly, it took a non-bacteriologist to make the observation that all the little colonies look alike indicating that the ant track in only one type of bacterium. What is it? Do all insects track in the same type? Is this a type that protects the ant from infection such as your body does by coating your skin with Staphylococcus epidermidis? All these are unanswered questions. Here is a possible useful hint: Look in Science News, vol. 155 (24 Apr 99) on page 261 about a finding that one type of ant carries an antibiotic producing type of microbe called Streptomyces.

Intestinal Bacteriology

When do mammals first acquire their intestinal bacteria? Evidence stongly indicates we are born with huge numbers of bacteria in meconium (intestinal contents at birth) (read Dr. Spock!). (Stefanie-VA, Allie-VA, Shanna-VA, Linzee-TX)
Needed: work on indentical twin human babies.
- Multiple births of both human and other animals.
- Especially needed are identical twins or the "congenic" babies of some mammals. Samples must be gotten as soon as the babies "pop out."

Controlling the Spread of Bacteria

Is your coinage self-sterilizing? This question can be attacked from many angles - enough for almost a whole class to divide among themselves.
Do bacteria speed the deterioration of metals? The Titanic explorers believe so. There are several ways to attack this problem.
Major Public Health Project! Make a survey of your surroundings for the numbers of bacteria on surfaces that are frequently touched by people. What is the nature of those surfaces you find rather sterile? Might this be recommended to your school officials for use on the other fixtures? (Afterall, none of you like being sick.)
- door-knobs
- railings
- faucets
- toilet flush handles
- chalk
- BARS of soap
- mouldings around doorways.

PLANTS

Why don't plants get "leaf cancer"? Early findings indicate that leaves are extremely UV-opaque indicating that UV light either is absorbed or reflected from them. The trick is testing whether or not the protection lies on the surfaces of leave, as expected. If you want to join in, here is what is currently being considered. A student has suggested injecting UV sensitive bacteria within the various layers of the leaf, then exposing the leaf with UV and later checking on the viability of the bacteria. (Carolyn-W&M, Abe-VI, Marcianne-VA, Sabra-VA, Jeff-VA, Scott-VA, Nathan-VA) Another method has been proposed in which a fluorescent dye is injected at various depths in leaves, and fluorescence is noted when the leaves are under UV light. (Todd-W&M)

Guard-Dog Bacteria for Plants?See the brief discussion above on "Guard-Dog Bacteria." It is interesting that most plants are covered with the same bacteria that we animals are. Are they being used symbiotically to protect the plant from bacterial infection? There are many unexplored aspects of this problem. Recent data indicate that these lactic acid bacteria do indeed reside inside of the leaves. But your help is needed for a much more in depth study of this topic. (Carolyn-W&M)

Transpiration is the overall process of moving water from the ground and eventually evaporating it from the leaves. Your textbooks state that the water rises up the plant by the sum of three mechanisms: capillary action, root pressure and because of water's self-adhesion it is drawn up to replace the water that has evaporated from the leaves. This experiment will show that there is MUCH more to the story - but what it might be is not known. This is another fundamental biological mystery waiting for you to solve!

Evolution of Photosynthesis. Most students have had the experience of making paper chromatograms using leaf-cells that have been crushed onto the paper. Let's go one step further: test a wide taxonomic selection of plants: dicots, monocots, ferns, mosses, and so on. Does a pattern arise?

Why Ants Don't Like Most Nectars from Flowers. Hummingbirds like sweet things, be it either sugar water or sweet flower nectar. But in our daily experience we do not see many types of flowers being overrun by ants in search of the nectar. What are the plants doing to protect their "sweets" from ants. First, get yourself "up to speed" by reading some of the ant experiments on the ants, below. Then consider the possibility that many plants add ant-repellent to their nectar. Two things we can gain from our experience is that this additive is neither toxic nor distasteful to hummingbirds. The problem you can try to solve is this: if you had a sugar solution that ants like, what would happen if you mixed this with the nectar of some flowers that did not attract ants. Can you make your sugar solution no longer attractive to the ants? Don't forget to include the appropriate controls. A later project would be identifying the anti-ant substance. And consider how much human food in the world is contaminated and stolen by ants.

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ANIMALS

Very few vertebrate animal experiments will be shown in this site since such work generally requires the approval of your school's committee dealing with reseach on animal subjects.

Behavioral Studies on wild animals such as the seals and sealions on the West Coast, or how clever squirrels are in figuring out backyard mazes to acquire peanuts make very interesting reports.

Insects make outstanding animal subjects - especially for younger students.

Consider, for example, what is the ratio of strength over weight for insects? Slow moving beetles can be captured and harnessed to pull loads. How heavy the load? How heavy the beetle? (This would give a lot of experience in graphing and chi-square analysis. Not to mention overcoming any squeemishness about handling beetles.) A favorite beetle for this is the Bess Beetle, which is a slow moving eater of decaying word - doesn't bite! - and can be up to 4 cm long with a great "waist line" for hitching up a string tether.)
Plastic petri plates placed next to each other with little openings between them are excellent basic devices for studying insect behavior. Put filter paper on the bottoms of the plates. Make one moist the other dry; make one well-lighted and the other in the dark (or covered with various colors of transparent plastic; place them on a slant to see if the insects prefer being "up" or "down"; place checker-board patterns in the plates, and see if the insects show a preference for where they sit - on the dark or on the white.
Ants: what concentration of sugar to they prefer. Somewhere near a colony of ants place little cups containing various concentrations of sugar water. Return in a few hours or the next day to see which cup has the largest crowd of ants visiting it. The same can be done with variously flavored candies, or even with sugar water plus flavorings off the supermarket shelf.
More ants: Take the previously discovered favorite concentration and then add what you think might be repellents to various little cups.
Worms. These creatures are very sensitive to things in their environment, and will noticably recoil when contacted with something noxious. Strips of filter paper dipped in various liquids can be used to touch the worm with it to notice what reaction is elicited (sugar, salt, acid (vinegar)). These can also be done quantitatively by using different concentrations of one that does give noticable results at a high concentration. What is the worm's threshold? It is an all or none response, or is it graded from a great response to a smaller one?

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