BIOS Work Tape

The sound you just heard our gobbles of wild turkeys here in Stevens State Forest Not very many people have seen a wild turkey But there are literally hundreds of them in this small tract of forest land in south-central, Iowa They're scattered populations of the mills were in the state also that have been introduced by the Iowa, Conservation Commission tonight We're going to look at the eye of the wild turkey in Iowa Benjamin Franklin thought that the wild turkey out to be our national bird It's always been associated with wildness and naturalness and anyone who's ever seen one can tell you it's a very exciting experience Benjamin Franklin called them a noble bird well besides looking at that noble bird itself were going to look at some of these studies that wildlife biologists are doing with the population here in Stephens Wild turkey is native to Iowa, but was extinct in the state until it was reintroduced in this century I always used to have large areas covered with the kind of forest habitat that the wild turkey needs Most of those forest areas are gone now, but the Stevens State Forest is an exception So this is one of the areas where turkeys have thrived since they were brought back to the state The eastern wild turkey is the subspecies which was native in, Iowa This is only one of six subspecies that at one time covered a large portion of what is now the United States Our domestic birds are descendants of the Mexican wild turkey native to this area Turkeys were first domesticated by the Indians of Central America who raised them primarily on corn We have been involved in a fairly large turkey restoration program for about the past five years Transplanting wild birds to various timbered areas all over the state and As a result of this release program. We are seeing turkey populations in Timber habitats that we did really not expect them to survive and do well in at all where we released him on a pretty much on an experimental basis and Because of this we these birds were surviving in these small scattered timber blocks We wanted to know more about why these birds were doing as well as they were in Iowa wild turkey is supposedly a bird That can only survive in large extensive tracts of timber 10,000 20,000 acres And we just don't have that much timber in Iowa in any one block our timbers tend to be Small scattered blocks long river bottoms and that sort of lives. Oh Viable there's no actual good evidence Or experimental work. That's ever been done on this But indirect evidence and superficial evidence would indicate that Most of these seeds will last the least 20 to 30 years and some of them probably will last 7 80 90 or 100 years where we've taken cores down into the mud and Taken off layers at a time and tried to germinate see just by spreading those layers of mud out in pans in the greenhouse And we get seed germinating from soil samples that come from like 15 18 inches deep into the mud which would mean probably they've Been there for 25 or 30 years Dr.. Davis, why are you involved in this kind of a study here in a marsh rather than some other kind of? That's a good question well Neither of us started out as marsh ecologists dr. Van der Valk started out working with Sand dunes on the east coast and I worked in the chaparral in California in forests in Michigan but if you're going to study natural vegetation in Iowa, you don't have very many choices and this type of Ecosystem is one of the few natural types of ecosystem in the state of Iowa it also Offers an opportunity to study a whole ecosystem Where we can measure inputs to the ecosystem and outputs It's what you might. Call a a nice unit that is easy to study because of its Distinctness from the surrounding environment either the forest to the west of us or the agricultural lands to the east and south Dr.. Rowley works with several species of mosquitoes that are common in Iowa some of these are what we call pest mosquitoes that is there Are merely annoying? Others carry dangerous diseases such as encephalitis and dog heartworm mosquitoes breed in water aquatic habitats of one type or the other and often fly large distances or long distances From these breeding sites into populated areas We know of some salt marsh mosquitoes and the Atlantic seaboard for example that are capable of migrating 100 to 25 miles in a single night and Iowa mosquitoes don't fly that far, but they're certainly capable of flights of up to 15 to 20 miles So they generally wouldn't have to fly that far probably and oil is generally they don't often. We raise our own mosquitoes in our backyard In studying mosquito flight dr. Rowley takes advantage of something that scientists have known for over 40 years That is when insects are suspended so that their tarsi or feet are not touching a surface. They will fly continuously most of the of the Apparatus was developed in the laboratory where I was working The attachment process and in other words getting the mosquito onto that little arm so that it can fly In a manner that is somewhat similar to what it would fly in nature is the tricky part actually the Gluing or the attaching of the mosquito to what we call a flight Male arm was very difficult, and it took a long time to resolve that process. We've tried a number of glues and adhesives and Methods for attaching sceetos until we came up with a a solution that worked on The Clintonville you're measuring The how far the insect claws you know the measuring how much work. It's doing. No actually the system is set up so that that the flight metal arm itself is perfectly balanced and Once the mosquito begins to fly Then it's just carrying itself there is very little work involved the the aerodynamics of the system has has been worked out and it's As near as we can possibly do in this type of situation a reasonable estimate of the flight ability of a particular mascara In order to separate the effect of one environmental factor That would influence flight from another doctor Roly uses an environmental chamber now this really looks like a meat locker But it allows Roly to control all sorts of things like temperature humidity and air currents Would you describe this research as being? More basic or applied or a combination of both or a little I think it's definitely a combination of the two actually, we're we're interested in mosquito flight as an entity in and of itself and all of the ramifications associated with it and We hope that it has some application in that if we can determine some of the characteristics that mediate mosquito flight this may be of some value to mosquito control abatement programs it certainly has value in terms of studying the epidemiology of the diseases we were just talking about It's very important to know how four particular species of mosquito can fly From roley's study of mosquito flight we moved to a project that could eventually lead to mosquito control Graduate student Sara Lindquist is studying the feeding habits of tiger salamanders, which are also relatively common in Iowa again We're looking here at a study of a single organism I guess the natural question to ask is why would someone study feeding behavior salamanders Well, there's two reasons first of all it's just a general feeding behavior. Study not really related to Salomon It's just an attempt to try to quantify Behavior most of the literature prior to this time has been spent on Description of what an animal goes through but behavior really hasn't been quantified how many times do these animals go through these acts what percentage? of time do they spend in certain Feeding procedures things like that so it's just a feet general feeding behavior trying to quantify material Second of all like I said not much is known about salamanders at all and so I select this animal just the fact that there's a lack of knowledge on that animal and essentially the role of salamanders in the ecosystems have is not well known a General feeding behavior like this perhaps can be a pilot study used for something that my major professor, and I have been discussing is the role of tiger salamanders in control of mosquito populations a general feeding behavior study here such as how they find their prey what prey they will take perhaps could give us an idea of how they spend their time out in nature and We were thinking in terms of biological control salamanders in a farm pond, maybe taking a large supply of mosquito larvae each year and in fact be a good control for something like mosquito populations The larval salamanders spend the entire summer in these farm ponds sluice Ditches the adults spend most of the time there in the early spring really a lot of Data has been taken on stomach contents of these animals and they have found significant amount of mosquito larvae in the stomach's of of larval salamanders and adults The laboratory apparatus for this project is a four foot square box marked with a grid design that Lindquist uses to plot the exact movements of our animals a Mechanism rigged with an electric drill and fishing line allows her to suspend and move a controllable plastic worm over the box What I'm using this box for now and the reason it's gridded Is I want to talk about I wanted to get a handle on how far these animals will respond to a cue such as a visual stimulus or chemical stimulus and What acts they would go through trying to find that food item how do you suppose a setup like this? compares with the type of habitat that these organisms would normally be found in do you think the the information that you're Finding out is comparable to what they do in nature well I assume just the behavioral repertoire the acts The possible movements these animals can go through would be the same in this box the same as in nature I think the difference would be is what percentage of the time they spend an ax or what? perhaps what sequence they go through when they get an in get a Well something like an earthworm. I'm really not sure if they do most of their feeding on the surface Which would be comfortable to something I've got here or whether they do a lot of feeding underground In which case I'd be a very difficult study to try to do here in the lab in fact in the field I think To this point we've looked at several kinds of basic research and most of the biologists involved in that research have in mind some practical Application of their work we thought that dr. Eugenia Ferrara Zoologist researching bullfrog endocrinology said it particularly well when she said that the unknown Quality of what a scientist might find provides part of the rationale for her studies there are lots of different reasons for studying Animals that aren't mammals. I like to think of the analogy of how an endocrinology The parathyroid gland which controls your calcium. Level was discovered in the rhinoceros and Somebody would say well. Why did we ever bother to look at the rhinoceros? And it's a good thing somebody did dissect one of these great big creatures because they discovered a gland that had Previously not been known and it turned out to be very important to all of humankind Edinson in the Physiology of everyone, so you don't know what you may come up with that's part of the excitement of it What we're doing right now is a project involving the study of the activity of the nervous system of the earthworm using animals which are totally Undetected and undisturbed we can actually pick up the electrical activity arising from nervous system elements and record this and analyze this and Also correlate the electrical activity of the nervous system with the overall behavior of The animal and this is a relatively new approach with where you actually worked with undetected animals yeah, actually the earthworm offers an opportunity to Pick up the activity of individual nervous or nerve cell elements without ever having to go in and Surgically interrupt or disturb the animal in the case of earthworms there there are very large Nerve fibers within the nervous system, which produce rather large electrical signals Which can actually be picked up right from the surface of the skin of the animal? and Let me just turn this down a little bit The electrical signals can be picked up right through the skin of the animal And we can analyze that activity then without ever having to go into the animal So this is the advantage this is the advantage of working on the earth where am I? It's the the amenability or ease of studying it plus You can easily get them into the laboratory to them why I just said the Rope my backyard. That's an important place They're also except in the wintertime Well you want to show us something about well, let me just explain to you the the Arrangement that we have here We have our earthworms Within this circular arena Which is basically two concentric plexiglass rings the animal actually crawls over an array of? Recording electrodes which are basically silver wires? These recording electrodes then can pick up the electrical activity Generated by the nervous system of the animal as it crawls over this the the surface of this arena The neural impulses picked up by the electrodes are individually amplified Recorded and analyzed in a sophisticated custom-built set up in dr. Drew's laboratory This basic research with earthworms may lead to a broader study of how pesticides and other environmental factors affect these animals when of that kind of thing of the effects of environmental factors pesticides the animals in that environment Seems many many steps removed from something as as basic as an earthworm crawling across electrodes actually It's it's not it's not it's not at all very far removed. We could very easily Raise our earthworms under varying conditions or concentrations or under the presence of various kinds of pesticides and then test directly the effects of those Contaminants or pesticides on the functioning of the nervous system we can actually very easily determine the rates of conduction of nerve impulses down the length of the animal and compare the conduction rates for those nerve fibers Under the normal conditions versus the conditions, that would be pesticides present the equipment and dr. Drew's laboratory shows how much of modern biology depends on sophisticated often custom-built equipment In studies at the cellular level in biology. No other single modern instrument has had as great an impact as the electron microscope There are two types of electron microscopes the scanning electron microscope allows the scientists to view the surface of minut structures to view the interior microstructure of cells biologists use a transmission electron microscope which provides greater magnification Dr.. Joseph vials a cell biologist uses a transmission microscope to monitor biochemical changes within liver cells To use this instrument the specimen must be cut or sectioned file's explains how that is done material that we have prepared for sectioning is Embedded in this little block of plastic And when we want to section the tissue We trim the plastic away from the block to form a very small pyramid such as you see here then mount the block and a holder Such as this Then the holder is mounted in the microtome Like that And this particular microtome is set up to Give us sections of 500 angstroms or less in thickness That's perhaps a thousand sections out of the thickness of the dime We use a special knife for sectioning a piece of glass Which has been broken we use the fractured edge there the fracture plane as the cutting edge now when glass the molecular structure of glass is such that it forms a pyramidal crystalline structure, and when you break it it tends to break along the pyramid structure, so you wind up with a single molecular layer of silicon oxide at the very surface We have the broken knife, and then we have a boat Made out of plastic tape which is wrapped around the top of the knife now this boat is filled with water the microtome will drop the sample down over the knife edge a section is cut off and it floats directly out on the water surface when we pick the sections up With a copper grid It's got about 300 holes per inch in the surface we simply dip the Dip the grid into the water boat like this and then pick the sections up on the grid surface drain the water off underneath and They're ready to be stained and examined with a transmission electron microscope We apply high voltage to the filament okay, 50,000 volts of electricity is applied to a Tungsten filament that's contained in this part of the microscope it projects well as the high voltage goes through it it boils off electrons and just like a lamp filament an electric light and the Electrons are projected down the column through the specimen And then this series of lenses in this region and in this region spread that beam Spread the electrons out so that we can then magnify the image that we look at on the screen here Because we're using electrons we have to use electromagnetic lenses, so these are really giant electromagnets We focused the beam with the electromagnetic field generated by these lenses Our last visit was with dr. Donald Nevins a plant physiologist The development of his research points out clearly how research into a basic problem in this case it was with plant hormones Has matured very quickly into a medically important investigation well, I was raised on a on a farm and took my academic training in agriculture with the idea of Learning to improve the basis for agricultural productivity well I still am primarily interested in agricultural research, but it at one particular point I decided that What we really needed for agricultural research with some some idea of fundamental processes in plants which a led led to crop productivity or improvement of crop productivity and I decided that I could spend my time during the next 15 years after getting my degree or so in In studying some of those fundamental processes, which I'll have later application to direct productivity in agriculture nevins research involves a biochemical study of plant hormones He uses the seedlings of corn and oats to study these compounds very little was known about how cells enlarged how they became Elongated to form taller plants or larger seeds and so we examine some of the some of the known information and Recognize that a lot of this is controlled by hormones, which are very simple substances in plants which have very profound effects while studying plant hormones and plant growth nevins isolated a molecule in the cell wall of corn seedlings Which could have an important impact in the field of medicine? during the last Two years I suppose We we made an intense intensive investigation into the structure of some of the key Compounds which are components of the cell wall we feel if these particular components our interest in these components was their role in plant growth and So we characterized them very carefully so that we could understand the molecular interactions these compounds that we've isolated appear to be very very similar in structure in structure to Some compounds which have anti tumour capacity in certain types of animal cancer Nevins has recently submitted a proposal to the National Cancer Institute asking for funds to further study these compounds I'm not an expert in in in animal or Medical Sciences, but Our part of the work of course will be to to characterize the compound further characterized as structurally repair Purified samples and then submit these for additional testing You