Abstract: The eggs of Vampirolepis microstoma were studied to elucidate the basic structure of the embryonic envelopes. Intact proglottids were processed by standard techniques for transmission electron microscopy (TEM); others were prepared for scanning electron microscopy (SEM) following ethanol cryofracture in liquid nitrogen; and others were prepared for light microscopy following standard techniques. TEM and SEM revealed that the fully developed eggs possessed the basic embryonic envelopes characteristic of all previously studied cestode species. In all fully developed eggs oberved the outermost layer was an electron-opaque embryonic capsule. The outer and inner embryonic envelopes situated proximal to the capsule were separate syncytial layers. Each contained ribosomes distributed throughout a moderately electron-dense cytoplasmic ground substance. The envelopes differed in that only the inner contained mitochondria and lipid droplets. The distal region of the inner envelope possessed a laminated substructure, the layers of which alternated in electron density. The inner envelope’s proximal region was occupied by an electron-dense embryophore that had a homogeneous substructure and uniform thickness. The polar filaments appeared to be located within the distal inner envelope cytoplasm, but the nature of its connection with the embryophore was not determined. When compared with earlier reports on Vampirolepis nana, these data suggest that the description of a separate polar filament sac proximal to the embryophore was based on examination of immature eggs.

Kayser, Nicole A. (1990) Left and Right Nostril Interaction in the Perception of Binasal Odors in a Normal Population

Abstract: The purpose of this study was to determine how the two nostrils interact in the binasal perception of odors in a human population which is free from nasal disease. After determining that they were free of asthma, allergies, polyposis, rhinitis, and that they scored within the normal range on a standard smell identification test, twenty-five college students were administered the Odorant Confusion Matrix (OCM)(Wright, 1987) in order to assess their uninasal and binasal olfactory abilities. The OCM consists of a series of ten odorants chosen to represent common household substances. The ten odorants used in the present study were ammonia, cinnamon, licorice, mint, mothballs, orange, rose, rubbing alcohol, vanilla and vinegar. Each subject was asked to sniff a bottle of liquid containing one of the ten odorants, and from a list of the ten odorants, identify which odorant he/she had smelled. A set of 11 blocks of the 10 odorants was administered to the left nostril, a set of 11 blocks to the right nostril, and a set of 11 blocks to both nostrils, with the order of left, right, and binasal simulation randomly assigned.

To help examine the relationship between uninasal and binasal olfactory performances, four models were tested, which from different theoretical points of view, might explain the relationship between the binasal and uninasal OCM scores. The model in which the better of the two uninasal scores by odorant was used to predict the binasal score for that odorant, best predicted the observed binasal data. This model implies that when processing olfactory information, inputs from each nostril are considered in odorant identification. The success of this model might also suggest that in any given sniff, the nostril, either right or left, that presents the stronger or clearer signal, will determine the binasal olfactory response.

Rock, Michael P. (1990) The Effects of Sodium Depletion on Sodium Taste Hedonics

Abstract: The purpose of this study was to determine, in human subjects, if the preference for sodium chloride changed after sodium depletion. Twenty (n=20) college aged subjects were asked to rate their liking or disliking of distilled water and 8 salt solutions on two separate days. On one day, subjects scaled the taste solutions after spending 10 minutes in a sauna (60-65 oC), and on the other, subjects did the scaling without having first had a sauna. The experiment was counterbalanced for order effects; some of the subjects did the sauna day first, whereas others did the non-sauna day first. During a testing session, each of the nine solutions were tasted and rated three times using absolute magnitude estimation (without a modulus) procedures. Eight of the test solutions contained one of four concentrations of sodium chloride (.32%, 2.5%, 5.0%, 10.0% wt/vol) dissolved in either distilled water or tomato juice. The nineth tastant was distilled water. Subjects were given 10ml, instructed to place the entire quantity into their mouths, expectorage, and then rate the solution as being liked or disliked. Additionally, subjects were asked to assign a subjective number to the amount of liking or disliking of the tastant. Subjects rinsed throughly with distilled water before tasting the next solution. The average of the second and third trial ratings for each tastant were used in the data analysis.

Analysis of variance tests revealed no differences in taste preferences for sodium chloride in relation to sauna exposure. In addition, no sex differences in sodium taste hedonics were observed. In general, there was an inverse relationship between the hedonic ratings and saltiness of the solution., in that subjects tended to dislike the solutions more with increasing concentrations in sodium chloride. Additionally, the choice of solvent (tomato juice or water) did not seem to affect the hedonic rating of the salt solutions.

Tompkins, Judith (1990) Modelling and Measuring Reproductive Efficiency in Sporocarps of Gilled Mushrooms

Abstract: The relationship between reproductive efficiency (gill area per unit weight) and sporocarp weight was studied for 42 sporocarps, representing 32 gilled mushroom species. The JAVA image analysis system was used to measure the surface area of each of three gills dissected away from each tier of the sporocarps. Fresh and dry weights were taken for the pileus and stipe.

Gill area increased with sporocarp weight. The gill area per unit weight, however, was smaller for heavier sporocarps. Speculations were made concerning the evolutionary significance of the relatively smaller reproductive return (per unit weight), for larger sporocarps.

Chojnacki, Karen (1991 ) - Changes in Olfactory Ability During the Course of an Upper Respiratory Infection

Abstract : To determine the impact of an upper respiratory infection (URI) on olfactory ability, 15 college students were identified as having URI’s and were given odorant threshold and identification tests. The threshold test consisted of a series of dilutions of phenol ethanol and propylene glycol. The identification test used was the Odorant Confusion Matrix (OCM) as described by Wright (1987).

Thirteen of the 15 subjects showed at least a 20 percentage point increase in OCM scores during the course of their recoveries from the URI suggesting that olfactory ability was impaired as a consequence of the infections. Data from these 13 subjects were then compared by right and left nostrils, and better and worse nostrils. The better nostril was identified as the nostril scoring higher on the OCM at the final testing session. Left and right nostrils both improved an average of 43 percentage points. The better and worse nostrils also recovered an average of 43 points. An analysis of covariance revealed that the left nostril of all subjects recovered at 1.2 percentage points per day (test of equal slopes P>.05). On the other hand, analysis of covariance revealed that the right nostril of all subjects recovered 4.1 percentage points per day (test of equal slopes P>.01). In a similar manner, the subjects’ worse nostril recovered 1.3 points per day while their better nostril recovered 3.6 points per day (test of equal slopes P>.05). A Friedman’s test of subjests’ right nostrils indicated that the mothball odorant was the only one that could be identified as accurately at the height of a URI as after recovery. In contrast, subjects had difficulty identifying mint with their right nostril during and after recovery from the URI. A Spearman’s Rank Correlation showed that threshold levels and OCM scores do not indicate similar levels of olfactory ability.

The results of this experiment may prove useful in describing the normal recovery pattern of olfactory ability during the course of and recovery from a URI. These data may also provide limited evidence for the hypothesis that loss of olfactory ability is caused by selective, short term receptor damage in addition to congestion of the nasal cavity.

Quinn, Colleen M. (1991) Ultrastructure of the Ovarioles and Egg Chambers of the Caddisfly

Abstract: Light microscopy and transmission electron microscopy were used to examine the general ovarian structure and cellular composition of the oocyte and associated nurse cells and follicle cells in Brachycentrus incanus adults. The ovary consisted of numerous meroistic polytrophic ovarioles, each containing at least one actively maturing oocyte. The major volume of the ooplasm consisted of electron-dense yolk bodies, and lipid droplets. An oocyte nucleus was discernible in previtellogenic stages. Seven nurse cells were found at the distal end of each oocyte, and were connected through cytoplasmic bridges. The large lobate nurse cell nuclei were characterized by uniformly spaced patches of heterochromatin and numerous nuclear pores. The cytoplasm contained mitochondria, a small amount of non-dilated granular endoplasmic reticulum (GER), agranular vesicles and a large number of free ribosomes. Follicle cells surrounded the periphery of the oocyte and were characterized by large oval nuclei with a moderate number of nuclear pores and abundant heterochromatin; the cytoplasm contained abundant dilated GER, mitochondria, Golgi apparati and free ribosomes. Oocyte microvilli interdigitated with those of the follicle cells through an extracellular matrix of variable electron density. Endocytotic vesicles were seen in the periphery of the oocyte cytoplasm.

Babapulle, Mohan N. (1994) The Early Development of Membranipora Membranacea: An Ultrastructural Study of Larval Morphogenesis

Abstract: Six pre-larval (0-24hrs.) stages of Membranipora membranacea were examined by light and transmission electron microscopy. The stages studied were: uncleaved zygote (1cell, ,75 mins. After spawning), 2 cell (75 mins.), prevestibule formation (16-128 cells, 2-14 hrs.), apical disk rudiment (19 hrs.), vestibule formation (20 hrs.), and the swimming gastrula stage (24 hrs.). The one cell stage showed the presence of abundant microvilli, arrays of endoplasmic reticulum, mitochondria, yolk granules/lipid droplets and vesicular elements. The two cell stage displayed a marked polarity in the animal and vegetal cytoplasm present in the cells in that most of the yolk granules in the cells were concentrated at the vegetal hemisphere in each cell. The polarity of the animal and vegetal cytoplasm seemed to influence the organization of cells in the 16-128 cell stages, with the vegetal cells containing abundant yolk granules primarily occurring to the center of the spherical ball of cells and separated from the animal cells surrounding them by the blastocoel. This arrangement of cells was also observed in he apical disk stage. In the vestibule formation stage, the animal and vegetal cells had rearranged to form a concave mass of cells. The lower tier of cells seemed to be vegetal in origin and distinct from the upper tier of animal cells. Presumptive coronal cells were also visible. The 24 hour swimming gastrula stage was shaped much like a laterally compressed bowling pin. Most structures of the fully developed larva were not visible in this stage, although some rudiments were. The only differentiated areas in the swimming gastrula seemed to be the cells of the apical disk, the corona and the oral epithelium. The cells of the oral epithelium contained abundant microvilli notably absent from the cells of the aboral epithelium. The larval neuromuscular cord was in the process of being formed, and appeared to originate from at least two cells in the apical disk. This nascent neuromuscular cord divided into two distinct branches-one leading to the area of presumptive endodermal cells (gut, internal sac, etc.) and the other down the length of the swimming gastrula, presumably to the yet undifferentiated cells of the pyriform organ where the larval neuromuscular cord ends.

Worland, Scott (1994) - Determination of Nght Roosting and Foraging Locations for a Colony of Common Terns (Sterna Hirundo) Nesting on the St. Lawrence River

Abstract: I identified foraging and night roosting habitat for a small colony of Common Terns (Sterna hirundo), nesting on an island in the St. Lawrence River near Massena, New York. As a New York State threatened species, Common Terns nesting habitat is protected. Night roosting locations and foraging locations have not been identified. I determined night roosting locations by using radio telemetry for 5 resident birds over a period of 2 weeks. Results from radio telemetry reveal that the birds utilize navigation cells located between 9 and 20 km upriver from the colony for night roosting. These cells also contain 95% of all tern nests in this sector of the river. I determined tern foraging locations by following resident birds with a small boat throughout their daytime foraging trips. Feeding trips lasted on average 23 min and covered approximately 10 km per flight. Completely tracked flights had a mean maximum range of 3 km. Although, the terns utilized a wide variety of locations, the northern shore of Long Sault Island was most frequented in foraging flights. Some birds were observed foraging almost 9 km away at the Moses Saunders Hydroelectric Dam. The determination of night roosting and foraging areas provides insight into tern ecology on the St. Lawrence River. The identification of areas used by this Threatened species may be important in the planning and development of recreational facilities on nearby islands and shoreline.

McGraw, Kevin J. (1997) How Specific are the Interactions of Tropical Hummingbirds and Flowers?

Abstract: I measured both bill lengths and corolla lengths for a community of hummingbirds and hummingbird-pollinated flowers at a montane forest site in southern Costa Rica. These data were combined with flower visitation prreference by the hummingbird species to examine the correlation between bill morphology and corolla morphology for all hummingbird/flower interactions. Three hummingird species and six flower species were abundant enough for analysis. I was able to divide the hummingbirds into two distinct “guilds” based on statistical differences in bill size (short and long), and divided the flowers into three groups based on corolla size differences (short, intermediate and long). I did not find discrete species interactions, but rather general preferences were noted, whereby small-billed hummingbirds preferred to visit small-flowered plant species and large-billed hummingbirds preferred to visit large-flowered species. Such results implicate a diffuse coevolutionary system, which contrasts early hypotheses that claimed hummingbird/flower interactions were the work of reciprocal coevolution.

Kring, Lawrence I. (1998) The Role of Cell Membrane Domains and the Actin Cytoskeleton in the Activation of T Lymphocytes by Their Receptor for Foreign Antigen

Abstract: T lymphocytes are cells of the immune system responsible for the specific recognition of invading particles and the subsequent activation of the immune system and/or the destruction of the foreign antigen. The T cell receptor recognizes and binds to foreign antigens and upon doing so initiates a signaling cascade to activate the cell. For this activation of T lymphocytes to occur, the proteins involved in the signal transduction must be brought into close proximity to the receptor for foreign antigen. In many cells, important signaling molecules such as tyrosine kinases are found in specialized membrane domains which contain glycolipids, cholesterol, and proteins attached by a glycosyl phosphatidyl inositol (GPI0 anchor. We believe that these domains interact with the T cell receptors upon activation by antigen exposure, or in our case by antibody crosslinking. To test if these domains associate with receptors, we utilized sucrose gradient ultracentrifugation. If the receptor associates with these domains it is expected to be found in a less dense region of the gradient due to the lipid content. This was found in our preliminary experiments. Further experiments then attempted to visualize this phenomenon using fluorescence microscopy. An anti-T cell receptor antibody conjugated with FITC was used to label (and thus visualize) the receptor. When the receptor was labeled, other proteins were also labeled to determine their association with the T cell receptor prior to and following activation. CD55 and CD59, markers of the specialized glycolipid domains, were labeled with antibodies conjugated with phycoerythrin so that their location could be compared to that of the receptor. Finally, experiments were conducted to determine the role of the actin cytoskeleton in this process of aggregation and activation. In these experiments rhodamine phalloidin was used to label the F-actin prior to and following cellular activation.

Avrich, Erin (1998) Fetal Mouse Calvaria Cells Released Into Culture

Abstract: Fetal calvaria cells are used to study implant osseointegration and osteogenesis. Fetal mouse calvaria were obtained from mice 13-15 days gestation, digested with collagenase, and seeded to culture flasks. After 21-25 days in culture, phase contrast microscopy revealed that the calvaria had become confluent, but that there were groups of glial/neural appearing cells growing on top of the calvarial lawns. Glial/neural type cells were found to be opsinized (then subsequently lysed with serum complement) using four different anti-glial fibrillary acidid protein (GFAP) antibodies. Fetal mouse calvarial lawns that had been depleted of the glial/neural type cells using antibody-complement depletion were inoculated with fresh subcalvarial cells and it was seen that glial/neural type cells adhered and grew abundantly, giving the same morphology as the original glial/neural type cells. ELISA inhibition studies were performed to determine epitope specificity for the four anti-GFAP antibodies. Since GFAP is supposed to be an intracellular protein, demonstration of unique epitope specificities for the antibodies would suggest the presence of this protein on the surface of the glial/neural type cells. Light and electron microscopy of intact, extracted calvaria indicated adherent cells on the neural, subcalvarial side. At this time, we conclude that these cells are glial/neural contaminants in calvaria released sultures and tht GFAP may occur on the surface of the glial/neural appearing cells.

Clark, David E. (1999) Investigating the Interactions between T Cell Receptors and Detergent-Resistant Membrane Domains Utilizing Fluorescence Microscopy

Abstract: T Lymphocytes are cells of the immune system that recognize foreign antigene displayed on self cells. Upon binding to the presented antigen complex, the T cell becomes activated through a series of complex signaling events. The T cell binds to the antigen complex via the T cell antigen receptor (TCR), which has to aggregate and interact with various other molecules to activate the intracellular signaling machinery thereby initiating the signaling cascade. It is believed that the appropriate proteins are able to associate because of detergent-resistant membrane domains (DRMDs), which serve as “rafts”, upon which the various signaling molecules may interact. I attempted to visualize this phenomenon utilizing fluorescence microscopy. Various extracellular components on the surface of activated T cells were labeled with fluorescently labeled antibodies, and their interactions with labeled DRMD components were observed using fluorescence microscopy. Quentitative data analysis was done using confocal microscopy technology in conjunction with NIH imaging and Sigma Plot software.

Smith, D.J. (1998) - Effect of Nasal Dilators on Olfactory Function

Abstract: Previous work has demonstrated that subjects wearing nasal dilators rated olfactory stimuli as being more intense as compared with ratings done without nasal expansion. Since preliminary data suggested the presence of a nasal dilator did not influence sniff flow rate, volume, or dutation, the increase in intensity ratings was hypothesized to support a perceptual constancy model in olfaction (Chemical Senses 22:177-180,1977). To test this hypothesis, we compared results on threshold and identification tasks performed with and without nasal dilators. When wearing nasal dilators, subjects had lower butanol thresholds and were able to identify more odorants on a low concentration version of the Odorant Confusion Matrix. As a further test of the hypothesis, we used a pneumotachograph to record sniff flow rate, volume and duration during the course of detection, intensity rating and identification tasks. Compared to the undilated controls, all sniff parameters increased when subjects were wearing dilators. These results argue strongly that nasal dilators affect olfactory ability by increasing the number of odorant molecules available to olfactory receptors. Although the present results do not negate the applicability of a size constancy model in olfaction, they do raise the possibility that at least part of the explanation of the perceptual constancy model may be a change in the regional airflow.

St. Martin, Mary (1999) Genetic Variability of Snails in the Little River

Abstract: Measurements of protein polymorphism were used to determine the amount of genetic diversity present in populations of two snail species, Viviparus georgianus (Subclass Prosobranchia) and Helisoma campanulatum (Subclass Pulmonata), inhabiting the Little River, Canton, New York. Allozymes for six loci, Aldehyde Dehydrogenase (AD), Aldehyde Oxidase 9AO), Glucose-6-Phosphate-Isomerase (GPI0, Mannose-6-Phosphate Isomerase (MPI), Phosphoglucomutase (PGM), and Xanthine Dehydrogenase (XDH), were analyzed using cellulose acetate electrophoresis protocols. Hardy-Weinberg equations were used to determine whether the population is at Hardy-Weinberg for each locus.

Although both Viviparus georgianus and Helisoma campanulatum are snails, they differ with respect to their potential mating systems. V. georgianus individuals have separate sexes, while H. campanulatum individuals are hermaphroditic (with one individual possessing both male and female reproductive organs). Consequently, V. georgianus indivisuals are obligatory cross-fertilizers, whereas individuals of H. campanulatum may fertilize their eggs by cross-fertilization, self-fertilization or a combination of both. Each mating system has different genetic consequences. For example, selfing results in the accumulation of identical alleles, leading to an increase in the number of homozygous individuals and a decrease in the number of heterozygous individuals. In addition to increased homozygosity in individuals, the overlying consequence of selfing is often a decrease in genetic variation within populations. One piece of evidence to support selfing in the H. campanulatum population would be a decrease in the number of heterozygotes observed at all or most loci compared to expected numbers based on Hardy-Weinberg predictions.

AD, PGM, XDH, and GPI were found to be polymorphic in Viviparus geogianus while PGM was the only polymorphic locus found in Helisoma campanulatum. Gene duplications were observed for MPI and GPI in V. georgianus population examined. In contrast, PGM was in Hardy-Weinberg equilibrium in both V. georgianus and H. campanulatum. Since Hardy-Weinberg predictions are met for the PGM locus in H. campanulatum, one could conclude that selfing (the most extreme form of non-random mating) is not occurring in the population or occurs at such a low frequency that its effects are not great enough to alter observed genotypic frequencies. Alternatively, selection could be offsetting the initial number of homozygotes produced by selfing by selecting for heterozygous individuals. An additional piece of evidence to support selfing in H. campanulatum is that he H. campanulatum population examined showed half as much average expected heterozygosity (H) as was measured in the V. georgianus population.

Babbie, Melissa (2000) Intercellular pH Regulation of glia in the Medullary Chemosensitive Site, the Retrotrapezoid Nucleus

Abstract: Ventilatory effects of CO 2 arise from chemosensitive neurons widely distributed throughout the medulla oblongata. One such site, the retrotrapezoid nucleus (RTN) plays an important role in sensing tissue levels of carbon dioxide, a by-product of oxidative metabolism. Carbon dioxide results in the subsequent formation of carbonic acid thereby acidifying tissues. Given that most biological systems utilize proteins and enzymatic pathways that operate within a narrow pH range, it is crucial that there is tight regulation of tissue acid/base balance. Intracellular pH (pH I) is regulated by membrane bound transporters that exchange acid/base equilavents across the cell membrane. Neurons in the RTN increase their activity with increased levels of carbon dioxide. Recent evidence has shown that glial impairment with the selective glial toxin fluorocitrate in the RTN of the anesthetized rat leads to a decrease in extraceulular pH (pH o) and an increase in phrenic nerve activity. This suggests that pH o and hence neural activity of chemosensitive cells may be influenced in part by glia. An initial step in understanding how glia may regulate pH o in this region of the brain is to identify the specie(s) of proton transporters present in this cell type.

In this study, transverse brain slices were prepared from juvenile rats and treated with the nrurotoxin kaninic acid to generate a slice devoid of neurons. The pH sensitive, fluorescent dye BCECF was used to monitor pH regulation in single cells in response to an acid load generated using the ammonia-prepulse technique. The kinetics of pH I recovery in RTN cells were monitored in both the presence and absence of pharmacological agents known to inhibit specific proton transporters. Cells were exposed to 4,4-disothiocyanatostilbenesulphonic (DIDS) to evaluate the presence of HCO 3 - dependent transporters and to amiloride to evaluate the presence of Na +/H + transport (NHE). This study revealed that there are two discrete populations of cells. One population of cells recovered from acidification utilizing an amiloride sensitive proton transporter. Based on previous studies it is likely that this transporter is NHE. In contrast, a second population of cells used a DIDS sensitive proton transport mechanism to recover from acidification. These data implicate HCO 3 - co-transport in some cells is supported by our observation that pH I in media containing CO 2 was more alkaline than pH I in CO 2-free media.

Landry, Aimee (2000)The Relationship between the Loss of Perceptual Intensity and Water Solubility in Subjects with Colds

Abstract: This study examined the hypothesis that the magnitude of the decrease in olfactory ability that is usually seen during a cold (Chojnacki et al., Chemical Senses 19(5): 453, 1994) is related, in part, to an odorant’s water solubility (Hornung et al., Chemical Senses 20(6): 710, 1995). After subjects with upper respiratory infections were confirmed to be hyposomic by scoring between 20 and 30 on the University of Pennsylvania Smell Identification Test (UPSIT), sixteen subjects rated the perceptual intensity of 18 odorant stimuli using the Green Scale (Chemical Senses 18:683-702, 1993). The test series was composed of nine odorants chosen based upon their water solubilities (Propionic Acid, Butyric Acid, Isopropanol – highly water soluble; Hexanol, Trans-cinnamaldehyde, Hepanoic Acid – moderately water soluble; Octanol, Hexanoic Acid, Pentanol – water insoluble). Each odorant was presented at two concentrations resulting in perceptual intensities of about 40 and 20 as judged by normosmic control subjects. Subjects with colds also used the Green Scale to rate the brightness of a series of lights. After the cold had resolved, subjects repeated the odorant and light intensity ratings. The perceptual intensity of the highly water soluble odorants was resuced by 41% in subjects with colds, whereas the intensity was reduced by 29% for the moderately water soluble odorants and only 18% for the water soluble odorants. The cold did not affect the light intensity ratings. We hypothesize that during a cold there is a direct relationship between an odorant’s water solubility and the percent of incoming molecules that are sorbed by the narrowed passageways. As a result, water soluble odorants have comparatively fewer odorant molecules that reach the headspace above the olfactory receptors and so the perceptual intensity for these odorants is more dramatically reduced during a cold.

Njuguna, Njogu J. (2000) - The Kinetics and Temperature Dependence of F Sex Factor Mediated Conjugation in Escherichia coli

Abstract: The object of this study was to determine of the kinetics of high frequency recombination (Hfr)-mediated DNA transfer through the F pilus, as well as the effects of temperature on this form of conjugation. Assays in which HfrC prototrophic donors and multiple auxotrophic recipient cells were separated using 6 mm thick polycarbonate filters containing 50nm wide pores (Nucleopore) were carried out under a variety of conditions. Each filter contained approximately 10 8 pores that ran straight through, i.e. the pores were straight not tortuous.

Conjugation at 37 °C was found to occur at a high rate for the first 15-30 minutes, following which no further transnfer was seen. In a single trial, no significant temperature-mediated effects were seen in the rate of conjugation, but further trials are eeded before a definite conclusion can be drawn. In addition, transfer of loci distal to the origin of transfer (his locus, 79 minutes) was found to occur within an hour, indicating that the rate of transfer on the solid media assays appeared faster than in liquid media matings.

These results indicate that F sex factor mediated conjugation was more stable on solid surfaces than in liquid media, possibly because on the solid surfaces, that mating pairs are stabilized against the membrane filter. Such stabilization may possibly eliminate the shear forces caused by Brownian motion, which are capable of causing the mating pairs to break apart before DNA transfer takes place.

The plating of a limited number of recipient cells on selective minimal agar plates to enable the quantification of exconjugant formation may have been responsible for the high rates of exconjugant formation during the early time reference study, following which no more transfer was seen. By plating a much larger number of donors than recipients, the likelihood that ecipients made contact with donor cells was very high, and as a result, the rate of exconjugant formation observed in this study could have been a reflection of an initial burst of conjugation activity later limited by the absence of non-recombinant recipients.

Banagan, Kelley (2001)The Ventilatory Effects of Sodium/Hydrogen Exchange Inhibition in the NTS

Abstract: The brain stem is the principal site of carbon dioxide sensing in the brain. The chemoreceptive regions are pH sensitive and regulate ventilatory responses to hypercapnia. The sodium hydrogen exchanger (NHE) is believed to be the membrane transporter that regulated the intracellular pH (pH I) in one chemosensitive site, the nucleus tractus solitarius (NTS), located in the dorsal medulla. Previous studies in vivo have shown that the NTS plays an important role in central respiratory control. There are five known isoforms of NHE. The NHE isoforms differ in tissue distribution, kinetics, and their response to external stimuli. Isoform 1 (NHE1) and isoform 3 (NHE3) are widely distributed throughout the brainstem and may be the prominent protein transport systems permitting recovery from acid loads. NHE1 is the dominant Na +/H + exchanger in the plasma membrane, and is believed to work with cystolic NHE3 in the regularion of pH I, Previous studies, utilizing immunohistochemical techniques, have shown that NHE3 is aparsely distributed throughout the medulla. Previous studies have also shown that the inhibition of NHE3 acidified the pH I of neurons on the ventral medullary surface located in chemosensitive regions, without affecting the glia. In this study, I examined the ventilatory effects of selective NHE3 inhibitors. Adult rats were cannulated unilaterally in the NTS. Animals were exposed to progressive hypercapnia while ventilation was measured using a whole body plethysmograph. I found that there were no marked ventilatory effects with focal inhibition of the NHE1 and NHE3 sodium isoforms in the conscious rat. These findings suggest two possibilities. First, NHE1 and NHE3 may work in conjuction with each other such that both transporters must be blocked for pH I regulation to be impaired. Second, it is possible that a different NHE isoform may be the predominate one in this region of the brain.

Ferguson, Heather E. (2001) Effect of Environmental Temprature on Walleye Fingerlings (Stizostedion vitreum) Immunized Against Bovine Serum Albumin (BSA)

Abstract: Walleys (Stizostedion vitreum) are freshwater fish, found mainly in northern, cold bodies of water such as the St. Lawrence River, Hudson Bay and many Canadian and northern United States fresh water bodies. The seasonal temperature variation of water temperature had a significant effect on walleye immune systems. At higher temperatures the strength and speed of an immune response increases relative to colder temperatures. This effect of temperature was suspected to occur in walleye, due to their response to Walleye Dermal Sarcoma Virus (WDSV). The virus was contracted in the spring when fish were spawning, tumors were seen in the fall, and slough off in the early spring. This research attempted to demonstrate the effect of temperature on the walleye humoral immune system. Walleye fingerlings injected with 0.33 mg of Bovine Serum Albumin (BSA) were held at 10C, 15C and 20C for 30 days before bleeding. An Enzyme Linked Immuno Sorbant Assay (ELISA) was used to measure serum antibody specific to BSA. Antibodies specific to BSA increased significantly between 10C and 20C. Total antibody concentration significantly increased between 10C and 20C, as well as between 15C and 20C. There was no statistical difference between serum protein concentration and temperature.

Kennedy, Caitlin (2001) The Ventilatory Effects of Gap Junction Inhibition in the NTS of the Conscious Rat

Abstract: The brain stem consists of chemosensitive and nonchemosensitive regions. Chemosensitive areas in the brain stem are known to regulate ventilation in response to acidification by CO 2. Acidosis of chemosensitive areas results in cellular depolarization causing neuronal firing, which increases ventilation through increased activation of the pre-botzinger complex. In one chemosensitive site, the NTS, adjacent neurons are linked through low resistance gap junctions. It has been hypothesized that electrical coupling between chemosensitive areas may permit rapid synchronization of neural circuits involved in ventilatory control. Using a push-pull cannula, placed unilaterally into the NTS, I wished to examine the ventilatory effect of disrupting electrical coupling focally in the conscious rat. Electrical synapses were blocked using the specific gap junction inhibitor, carbenoxolone. To evaluate the effects of carbenoxolone on central chemoreceptive sensitivity, I exposed the rat to progressive hypercapnia while measuring elimination of electrical coupling decreased ventilation at all CO 2 concentrations. Furthermore, the inhibition of ventilation with carbenoxolone appeared to be age dependent. Older rats exposed to carbenoxolone showed no inhibition of ventilation. These data suggest that the electrical synapses are important during development of CO 2 chemoreception, however the function of electrical coupling in central ventilatory control wanes with age.

Parisian, Keely R. (2001) Ventilatory Effects of Focal Acidification in the Nucleus Tractus Soliarius of the Conscious Rat

Abstract: Terrestrial animals are faced with the problem of ridding the body of carbon dioxide (CO 2). Unlike aquatic animals, CO 2 cannot diffuse across the skin and therefore a mechanism of elimination is necessary. Breathing is one essential process of eliminating metabolically produced CO 2. Upon hydration, CO 2 forms carbonic acid, which can denature cellular proteins and disrupt cellular functions. Since aerobic metabolism is an ongoing process, CO 2 represents a continual acid load to the body that must be regulated. Chemosensitive neurons distributed throughout the brainstem regulate systemic CO 2 levels by altering ventilation. One such dorsal medullary site, the nucleus tractus solitarius (NTS) is part of the solitary complex that has additional functions in cardiovascular control. The unique stimulus to CO 2chemoreceptors is not known although changes in neuronal activity is thought to be mediated by pH rather than molecular CO 2. It has been shown in vitro that intracellular pH (pH I) changes as a function of extracellular pH (pH o). It is hypothesized that as pH I becomes more acidic, CO 2 chemosensitive neurons increase firing frequency resulting in an increase in phrenic nerve output.

Although chemoreceptive sites are widely distributed throughout the brainstem, the predominant ventilatory effects of a given site appear to be dependent on the state of arousal (i.e. wakefulness, sleep, anesthesia). Unfortunately most of the work in the area of ventilatory control has been performed in the anesthetized rat. In this study, I examined the ventilatory effects of focal, unilateral acidification in the nucleus tractus solitarious (NTS) of the conscious rat. I found that focal acidification with 1 mM acetazolamide (AZ) perfusion increased ventilation during steady-state normocapnia and hypercapnia. Moreover, not all animals showed an increase in ventilatory minute expiration with AZ suggesting that CO 2 chemoreceptors may be discretely located within the brainstem. In summary, my study suggests that there is heterogeneity in the distribution of CO 2 chemoreceptors in the brainstem and that the NTS is important in ventilatory control in the conscious animal.

Wages, Page M. (2001) Developmental Changes in the Intracellular pH Regulation in the Medullary Neuron of the Rat and the Importance of Sodium/Hydrogen Exchange on pH Regulation and Ventilation

Abstract: CO 2 chemoreceptors in the brainstem are thought to play a role in the regulation of the rate of ventilation. The retrotrapezoid nucleus (RTN), a chemosensitive site was compared to two non-chemosensitive sites, the hypoglossal nucleus (HYP) and the medial vestibular nucleus (MeV) in the medulla. The chemoreceptive areas differ from neighboring non-chemoreceptive areas because they do not regulate the intracellular pH (pH I). Using an ammonia (NH 4Cl) prepulse, which acidifies only pH I, it was found that both the chemosensitive and non-chemosensitive areas regulated their pH, recovering quickly from the acid load. An increase in CO 2 concentration decreases the pH of both the pH I of chemoreceptive cells and the external pH (pH o). The RTN, in rats younger than 8 days, was the only area tested that did not recover from the acidosis, both the HYP and MEV recovered normally. Hypercapnia, therefore, resulted in an increase in ventilation due to nerve firings from the chemoreceptive areas, which did not recover from the acidification. However, the pH I recovery abilities of the neurons in the HYP were found to decrease progressively with age. In rats older than 8 days, hypercapnia resulted in sustained acidification in both the HYP and the MeV, similar to the effects seen in the RTN. However, the HYP and MeV neurons were able to recover from the NH 4Cl acidification of only the pH i. Comparing these three areas in the medulla, the mechanism of the pH regulation in the chemoreceptors was labeled, using amiloride and DIDS, as the Na +/H + transporter. The pH I recovering from acidification in the RTN neurons was found to be dependent on the extracellular Na + concentration, which was blocked by 1 mM amiloride. DIDS blocks the CO 2/HCO 3 - exchanger and 0.05mM concentration of the drug had no effect. This indicates the bicarbonate ion does not play a vital role in the regulation of pH I and pH o in the chemosensitive regions of the brainstem. The pH I recovery from intracellular acidification in the RTN,HYP, and MeV neurons is sensitive to changes in pH o in younger rats (less than 8 days) and not older rats (older than 8 days), indicating a developmental change in the chemoreceptive regions. Therefore, rats younger than 8 days have not yet developed the differential pH regulation between the chemoreceptive regions and the non-chemoreceptive regions. Transporters on the membrane must play a role in the regulation of cellular pH, and these transporters were only found on the membranes of the chemosensitive neurons.

In the whole animal, amiloride and DIDS prepulses were done and the ventilators were measured using a whole-body plethysmograph on Sprague-Dawley rats. The amiloride effects caused an increase in ventilation, due to the blocking of the Na +/H + transporter. DIDS had no significant effect on the ventilation of the rats, verifying the in vitro studies.

Smith, Ashlee (2002) The Effects of Pharmacological Blockade of Gap Junctions in the Nucleus Tractus Solitarius on Central Respiratory Control of the Conscious Rat

Abstract: The nucleus tractus solitarius (NTS) is an important site for integration of afferent autonomic reflexes. Regions of the NTS rostral (rNTS) to area postrema are involved in gastrointestinal and gustatory reflexes, whereas caudal sites (cNTS) are principally thought to be involved in cardiorespiratory function. However, CO 2 sensitive neurons have been identified in the rNTS using in vitro methods and in both the rat and the cat, focal acidification of sites within the rNTS increases ventilation 26-56% (8,19). These sites tend to be in the more caudal parts of the rNTS, but there does not seem to be a clear functional segregation of chemosensitivity along the rostro-caudal axis of the NTS.

Using brain slices, researchers have previously demonstrated the presence of electronic and anatomical coupling between neurons in both the rostral and caudal regions of the NTS(19). In this study, 85^ of the anatomically coupled cells were depolarized by hypercapnic acidosis, and 28% of the CO 2-excited cells were coupled to at least one other neuron. These findings suggest that electrical coupling may be an important aspect of chemosensory function in this region of the brain.

To determine the role of the NTS in ventilatory control in the conscious rat in vivo, I placed cannulas unilaterally in the rNTS. After recovery from surgery, we focally perfused artificial cerebral spinal fluid (ACSF), ACSF+ acetazolamide (AZ).

I found that unilateral, focal acidification with AZ significantly increased ventilation during normocapnia in the conscious rat. The increase in VE during focal perfusion of AZ was due principally to an increase in tidal volume. These findings demonstrate that the NTS plays an important role in respiratory control during wakefulness. Moreover, the respiratory effects of AZ perfusion in the rNTS were similar in all animals tested, regardless of age.

After the evaluation of the NTS as a chemosensitive site, the persistence of electrical coupling in the NTS was studied. Neonates do have a ventilatory response to CO 2, although this response is different from the adult (5, 21). Previous work in the NTS using brain slices has suggested that electrical coupling that is present in the neonatal rat may persist in the young adult and that coupled cells are both chemosensitive and increase their firing during hypercapnia (19). It is possible that reciprocal excitatory connections between coupled chemosensitive neurons may serve the amplify chemoreceptor output from the NTS. If depolarizing current flow through gap junctions raises the membrane potential of coupled cells closer to threshold of firing, then blocking current flow through gap junctions should decrease firing and chemosensitive output.

To evaluate the role of electrical coupling in central respiratory control, rats were cannulated unilaterally and focally perfused with ACSF or ACSF + carbenoxolone. In young rats (~7 weeks) carbenoxolone decreased expired minute ventilation across all levels of CO 2 compared to the ACSF control. These findings demonstrate that pharmacological blockade of gap junctions in the rNTS of the young rat decreases ventilation in vivo. However, to compare age related effects, rats of approcimately 13 weekswere focally perfused with ACSF, ACSF + carbenoxolone, or ACSF + GZA, which is the inactive analog of carbenoxolone. Among the older animals, none of the animals tested showed a decreased ventilatory response to CO 2 during carbenoxolone perfusion and the ventilatory responses to all perfusates, including GZA, were similar in older animals. These findings suggest that although the respiratory response to focal acidification with AZ is similar in young and old adult rats alike, the underlying neural circuitry in the NTS may undergo significant developmental changes.

Snyder, Kelly (2002) The Role of Glia in Central and Peripheral Respiratory Control

Abstract: Ventilatory effects of CO 2 and O 2 arise from central and peripheral chemoreceptors. The central chemoreceptors are located in the NTS, RTN, LC, pontin, and Raphe. The NTS and the RTN are the most important areas of the central chemoreceptors. These receptors respond to increasing CO 2 and decreasing pH. The carotid bodies make up the peripheralchemoreceptors and input their signal to the NTS. The carotid bodies respond primarily to decreasing O 2.

This study was performed in order to examine the role of glia in both the central and peripheral pathways during development in the rat. Sprague-Dawley rats with a mutation in the PLP gene were used in order to study the role of glia in central nervous system function. The ventilatory expression in normal and affected littermates was studied to determine if the role of glia and proliferation of glia differed during development.

This study revealed that both the central and peripheral chemoreceptors rely on glia for normal functioning. However, their signaling pathways are different and the widespread loss of glia affects them differently. This data also suggests that the carotid bodies undergo a change during development that may explain the transient decrease between P6-P10. Also there is evidence that the pons may not be affected by the dysfunctional myelination.

Spicer, Scott M. (2002) The Impact of Mucosal Solubility on Changes in Odorant Perceptual Intensity

Abstract: Using psychophysical and gas chromatographic techniques, this study examined the impact that mucosal solubility has on changes in odorant perceptual intensity. Thirteen normosmic subjects (UPSIT score greater than 35) rated the perceptual intensity of 9 odorants (propionic acid, butyric acid, isopropanol, hexanol, trans-cinnamaldehyde, heptanoic acid, octanol, hexanoic acid, pentanol) at 2 concentrations in 3 randomized test blocks using the Green Scale (Chemical Senses 18:683-702, 1993). Normosmic, nondilated controls rated the lower concentration of each odorant at a perceptual intensity of 20 and the higher concentration at an intensity of 40. There were two conditions, with and without a nasal dilator, with the order counterbalanced. As expected, when wearing a nasal dilator, subjects rated all the odorants as being more intense, however not all odorants showed the same increase in perceptual intensity. The odorants were ranked based on the relative increases in perceptual intensity. Gas chromatography was used to determine the relative mucosal solubility of the 9 odorants. 4 normosmic subjects, while performing velopharyngeal closure, had a continuous stream of odorant injected in one nostril. Molecules exiting the nasal passageways were collected from the contralateral nostril and the airstream sent to a photoionization dector. At equilibrium, the ratio of the number of molecules exiting the nose to the total number of molecules injected served as a means of ranking the relative mucosal solubilities of the 9 odorants. The ranking of intensity increases and odorant mucosal solubilities were highly correlated. That is, the three odorants that showed the least enhancement in intensity were also the three odorants that had the lowest ratio of molecules sorbed by the mucosal. There was a similar correlation between the odorants that showed the greatest enhancement in intensity and had the highest ratios. This correlation was shown to be significant using the Spearman rank correlation coefficient test. Although the perceptual intensity of an odorant is due to many factors, these data support the hypothesis that mucosal solubility, in part, determines how perceptual intensity will change as nasal anatomy changes. This hypothesis was then formally analyzed using 12 subjects who were hyposmic due to an upper respiratory infection. The same psychophysical techniques used above were used here in the subjects hyposmic due to colds. The ranking of intensity increasesand odorant mucosal solubilities, as determined in the normosmic subjects, did not appear related. The ranking of intensity increases also appears unrelated to water solubility. Spearman correlation tests showed that this was true. It appears that the content of mucus is changed during an upper respiratory infection, and therefore the sorption of the odorants in the mucus is altered. It is hypothesized that when nasal anatomy changes in normosmic subjects, olfactory ability is affected depending upon the odorant’s mucosal solubility. In subjects with upper respiratory infections this relationship is less understood because the mucus content appears to be different in different subjects.

DePuy, Kathryn (2003) The Contribution Each Nostril Makes to Olfactory Perception

Abstract: Utilizing the cyclic changes in the relative size of the airflow passageway for the two nostrils, Sobel et al (1999) observed that with an octane/carbone mixtre the nostril with the higher airflow was more sensitive to carbone, the highly sorbed odorant. The first series of experiments employed in this study was designed to determine if this “chromatographic” phenomenon occurs for other odor pairs and then to determine how the central nervous system deals with disparate information from the two nostrils when producing a binasal response. Using isointensive mixtures of carvone/octane, pentanol/butyric acid and isopropanol/hexanoic acid, subjects used single nostrils to rate the contribution each nostril made to the intensity of the mixture. After the single nostril ratings, subjects made the same determination using both nostrils. Although, the “Sobel” effect was observed for all odorant pairs, the nostril difference was less dramatic for the pentanol/butyric acid mixture.

Six models were generated which predicted the binasal response from the responses of the individual nostrils. In these six models it was assumed that the binasal perception was determined by one of the following: the response of the dominant nostril, the response of the non-dominant nostril, the response from the nostril giving the bigger response, the response from the nostril giving the smaller response, the response of the right nostril for right handers and the left nostril for left handers, and the average response of both nostrils. After comparing the binasal response with the response from the individual nostrils, three models: right nostril in right-handers and the left nostril in left-handers, the dominant nostril, and an averae of the intensity ratings from the two individual nostrils, emerged as the best predictors of binasal ability.

In an attempt to provide a more discriminating test of the various models predicting binasal response, a second series of experiments were completed where a number of modifications were made to the testing procedure. First, since bottles were used to deliver the odorant to the subjects, it was possible that there was not a trial-by-trial consistency in the concentration of odorant stimulus delivered to each nostril. Therefore, to better control the stimulus delivered to the nostrils, a delivery system was developed in which odor delivery tubes from the bottles were placed into the individual nostrils.

Second, since the uninasal responses in the first set of experiments were measured with the non-stimulated nostril closed, it was frlt that a more “natural” uninasal response would come from a stimulating conditioin in which both nostrils were open. To accomplish this, using the newly developed delivery system, subjects were presented with two bottles: one containing the odor mixture and one containing only the odorless solvent. With these two stimulation modifications in place, subjects were asked to make the same single nostril and binasal determinations as in the original study. Unexpectedly, these modifications eradicated the Sobel effect observed in the first study.

The unexpected eradication of the Sobel effect with this new delivery system was likely a result of the lower uninasal airflow rate. That is, when using only one nostril for the uninasal determination, all the inspired air was sent through that nostril; whereas in the second series of experiments when both nostrils were used, the individual nostril airflow was likely reduced. It is hypothesized that this reduction in nasal airflow caused the reduction of turbulence in that nostril, which in turn reduced the impact that mucosal solubility had on odorant separation. In addition, introducing the stimulus higher up in the nasal cavity likely reduced the effective mucosal surface for the chromatographic effect. Because the Sobel effect disappeared with this delivery system, it was not possible to further refine the model that predicted the binasal response.

In the third set of experiments the new delivery system was used to drastically change the stimuli presented to the two nostrils. It as hypothesized that a larger nostril disparity would allow for a better determination of the appropriateness of the various binasal models. Using very disparate stimuli, two of the six hypothesized models were shown to predict binasal ability: the dominant nostril and the nostril that yielded the bigger response. Although, because of the variability, these models could not be separated from the other four binasal models, demonstrating that binasal perception is a more complicated process than suggested from the six models tested in this study. In conclusion, the results of the present study again demonstrate that nasal anatomy can influence individual nostril sensitivity. Further, the binasal results provide additional insight into possible hypothesis to account for how the central nervous system is able to meld individual nostril differences into a single sensation.

Elvey, Christian (2003) The Role of the Locus Coeruleus in Cold Water Swim Analgesia

Abstract:

Previous studies have shown that the locus coeruleus (LC) subserves a variety of behavioral functions including attentiveness, central pain processing and more recently central respiratory control. We hypothesize that the other functions ascribed to LC predominate over its putative role as a central chemoreceptor site. To test this hypothesis, we attempted to dissociate the effects of pain processing from central respiratory control. The role of the LC in respiratory control is currently being evaluated in another study (Mary Schwab and Jaime Gallagher) by examining the respiratory effects of carbon dioxide following focal, neurotoxic lesions to the LC. In this study, we investigated the effects of cold-water swim on tail flick latency as a measure of pain threshold following LC lesioning. The descending pain pathway involves several pontine and medullary sites including the periaquaductal grey, parafasicular nucleus, raphe magnus and LC. The LC modulates pain processing using two pathways. First, it is responsible for opioid release into the dorsal root of the spinal cord. Second, it has inhibitory projections to the parafasicular nucleus, which stimulates opioid release from periaquaductal grey. Previous studies have shown that lesioning the LC decreases tail flick latency as a result of decreased opioid release arising from damage to the LC. We found that LC lesioning had a biphasic effect. Tail flick latency actually increased in the first few days following surgery, most likely arising from the removal of the inhibitory input to the parafasicular nucleus. When testing was repeated 10 days post-surgery, tail flick latency was decreased compared to baseline due to the lack of opioid release.

Frederick, Jaclyn A. (2003) Effects of Dibromoacetic Acid, A Water Disinfection By-Product, On Follicular Populations in Neonatal Rats  

Gallagher, Jamie (2003) The Role of the Locus Coeruleus in Respiration of the Conscious Rat

Abstract: The locus coeruleus (LC) has been implicated in several functional roles including pain processing, stimulating arousal, ad anxiety disorders. Recently, it has been suggested that the LC may also possess a ventilatory function. However, the role that the LC plays in central chemoreception is not clear. To determine what contribution the LC has on eupnic and hypercapnic breathing, bilateral injections of the LC were performed to assess the ventilatory effects to room air and hypercapnia using the whole body plethysmograph. Respiration of animals with bilateral injections of either artificial cerebral spinal fluid (ACSF), 5 mM kainic acid + ACSF, or 10 mM kainic acid + ACSF was measured in a progressive, graded series of CO 2 levels (0,2,4,6, and 8%) on days 1-7, and 14 following the surgery. No significant changes in expired minute ventilation (VE), tidal volume (Tv), or frequency (f) were found in either normocapnia or hypercapnia compared to presurgical baseline data in either ACSF or 5 mM kainic acid + ACSF animals. There was a small significant decrease in the V E, and T V of animals lesioned with the 10 mM kainic acid + ACSF concentration. Following physiological testing, brains were sectioned and stained for tyrosine hydroxylase (TH), and a confocal microscope was used to determine the number of TH positive cells in lesioned and control animals. Our study has found that there was a marked decrease in TH positive cells in animals lesioned with the neurtoxin, kainic acid (5mM-10mM), compared to control animals. These data suggested that the CO 2 sensitivity of ventilation in lesioned rats were not significantly different from that in non-lesioned animals. We concluded that the LC plays an important role in the brainstem, however central chemoreception is not a primary function.

Hewitt, Amy J. (2003) The Effects of Pharmacological Blockade of Gap Junctions in the Retrotrapezoid Nucleus on Central Respiratory Control of the Conscious Rat

Abstract: Gap junctions are distributed throughout the brainstem in regions of central respiratory control including the LC, the pre-Botzinger complex, the NTS and the RTN. Three experimental groups (8-10 weeks, 11 & 12 weeks, and 13-16 weeks old rats) were used to examine the developmental effects of gap junction blockade on ventilatory control. ACSF (artificial cerebral spinal fluid) + Carbenoxolone, a gap junction inhibitor, was perfused through the RTN via the push/pull cannula, while ventilatory effects were measured. The pharmacological blockade of gap junctions decrease expired minute ventilation (VE) by ~30% across all levels of CO 2 in young rats (8-10 weeks). The main contributor to this decrease in VE was a decreased tidal volume (TV). Perfusion of ACSF alone had little effect on VE, TV, or breathing frequency in these same rats. In contrast to the inhibitory effects evident in younger animals (8-10 weeks), rats 11-12 weeks of age showed no ventilatory effects with carbenoxolone perfusion whereas, older rats (13-16 weeks old) showed a significant increase in ventilation following gap junction blockade. These data suggest that the role of gap junctions changes with age in the RTN, as does the role of electrical coupling in respiratory control.

Labbe, John (2003) The Presence of Tannin Tolerant Bacteria in the Gut of the Eastern Grey Squirrel (Sciurus carolinensis)

Abstract: Tannins consumed in the diet of the eastern gray squirrel ((Sciurus carolinensis) are assumed to combine with protein to form tannin-protein complexes (T-PCs). Tannins inhibit the activity of digestive enzymes and decrease nitrogen absorption in the alimentary tract of many herbivores, which reduces the digestibility of protein bound in T-PCs. In this study, I isolated bacteria from the stomach, ileum, jejunum, cecum, ascending colon, and the transverse colon of a female gray squirrel onto Brain Heart Infusion (BHI) medium overlaid with either 2% condensed (quebracho tannin) or 2% hydrolysable (tannic acid) tannin solution and grew these plates in an anaerobic chamber. In order to examine the bacteria’s ability to degrade the T-PCs, I monitored their growth on the tannic acid overlaid BHI (T-BHI) medium and on the quebracho tannin overlaid BHI (Q-BHI) medium for the formation of clear zones around the bacterial colonies. Clear zones did not form around the bacterial colonies grown on either T-BHI medium or the Q-BHI medium, however bacteria isolated from each of the sections of the gut surveyed proved to be tannin tolerant by growing on the tannin treated medium. When the tannin tolerance was measured quantitatively, the gut flora was found to be resistant to tannic acid at concentrations as high as twenty percent. The tannin tolerant bacteria consisted of Gram positive rods and cocci and Gram negative cocci, most of which were microaerophilic facultative anaerobes. Some of the isolates found in the stomach, jejunum, cecum, ascending colon, and transverse colon possessed tannase, an enzyme that inhibits the ability of hydrolysable tannin to combine with protein. These results suggest that the gut flora of gray squirrels may not degrade T-PCs, yet some of the bacteria may assist in the digestion of diets containing tannins by prohibiting the formation of T-PCs.

Schwab, Mary (2003) The Functional Role of the Locus Coeruleus in the Conscious Rat

Abstract: The locus coeruleus (LC) has been found to have multiple roles including pain processing, stimulating arousal, and anxiety disorders. However, the role that the LC plays in central chemoreception is not clear. To determine what contribution the LC has on eupnic and hypercapnic breathing, bilateral injections of the LC were performed to assess the ventilatory effects to room air and hypercapnia using the whole body plethysmograph. Respiration of animals with bilateral injections of either artificial cerebral spinal fluid (ACSF), 5 mM, or 10 mM kainic acid was measured using a progressive 0-8%, graded (by 2%)CO 2 tests for days 1-7, and 14 following the surgery. No significant changes in expired minute ventilation (VE), tidal volume (TV), or frequency (f) were found during eupnea or hypercapnia compared to presurgical baseline data in 5 mM lesioned animals, however there were significant decreases in 10 mM lesioned animals. Following physiological testing confocal microscopy was used to determine the number of tyrosine hydroxylase (TH) positive cells in animals treated with 5 mM and 10 mM kainic acid compared to ACSF injected control animals. This data suggests that the CO 2 sensitivity of ventilation in lesioned rats is not significantly different from that in non-lesioned animals. We concluded that the LLC plays an important role in the brainstem, however central chemoreception is not a primary function.

Scott, Thomas J. (2003) Ontogeny of Basement Membrane Protein Expression in Rat Ovarian Follicles

Abstract: Immunohistochemistry was used to localize expression of basement membrane (BM) proteins in the ovaries of neonatal (4 and 7 days old), pre-pubertal (23 days old), and adult (60-90 days old) rats. Laminin was specific to the BM at all ages and in all stages of follicular development. Collagen type IV was present in ovaries at all ages, but only appeared to be specific to the BM of primordial and pre-antral follicles in neonatal rats. In older rats, collegen was localized to the BM of antral and atretic follicles. Fibronectin was not successfully localized to the BM at any age or at any stage of follicular development. While previous research has demonstrated the presence of all proteins in the BM, the current study provides evidence that localization of collagen type IV in rat ovarian follicles would appear to be dependent upon age. Reasons for this discrepancy are unknown and warrant further investigation.

Zagursky, Jennifer and Maureen (2003) Location of Glial Fibrillary Acidic Protein on Glial/Neural Type Cells Concentrated in Fetal Mouse Calvaria Cultures

Abstract: Glial fibrillary acidic protein (GFAP) is an intermediate filament protein found in certain types of glial cells. While this protein is normally found inside cells in order to support the cell’s sructure, there has been some evidence that there may be some cells which have GFAP on their surfaces. When fetal calvaria are harvested and cultured, a glial/neural type cell was an observed contaminant. In a past study, GFAP was observed to be a component of these glial/neural type cells but not in the calvaria feeder lawn (Avrich 1998). In this project calvaria cells were successfully cultured and produced well covering lawns in chamber slides. Using permeablized, fixed cells, the presence of GFAP was confirmed in the glial/neural type cells. Utilizing live cell culture, it was determined that GFAP may be on the surface of some of these glial/neural type cells and therefore would be a potential target for further study, such as the repetition of antibody opsonization and complement depletion trials.

Benard, Matthew J. (2004) Promoter Activity of the Human Chromosome 17p13.1 12-Lipoxygenase Gene in Cancer Cells

 Abstract: 12-Lipoxygenase (12-LOX) is one of several enzymes responsible for the metabolism of arachidonic acid (AA). While biologically necessary, the metabolites generated in this process have been reported to promote the development and metastasis of several types of cancers including breast, lung, prostate, and colorectal.

The promoter for the gene that codes for this enzyme has not been definitively characterized, partially due to the lack of typical consensus sequences, such as the TATA and CCAAT boxes. A 1083 base pair and a 551 base pair sequence upstream of the 5’ end of the gene were individually cloned into a reporter vector containing the Green Fluorescent Protein (GFP) gene. Jurkat (human leukemia) cells transfected with the reporter plasmid were cultured and the activity of the proposed promoter was quantified via fluorescence microscopy. Preliminary data suggests that no GFP was produced in this cell line.

Hayes, Brendan M. (2004) Does Dam Activity Restrict Gene Flow? A Test Using Elliptio complanata (Bivalvia: Unionoidea)

Abstract: The Raquette River is the second longest river in New York State and has had its hydrology tremendously altered by human activity. The river has twenty-one main branch and three tributary dams built for either hydroelectric power generation or the creation of reservoirs. Elliptio complanata, a freshwater mussel ubiquitous in the St. Lawrence River basin, has provided preliminary evidence that it can be used to elucidate questions about flow changes and stream capture events by looking at the COI and 16s rRNA genes in mitochondrial DNA. Elliptio complanata has a sedentary lifestyle but does have an ecto-parasitic larval stage that relies on attachment to fish gills for dispersal. Raquette River dams were built without fish ladders making them potential sources of habitat fragmentation. Our question is to see if nuclear DNA could be used to analyze the impact that dam activity has had on gene flow between mussel populations on the Raquette River.

During the summer of 2003, specimens of E. complanata were collected from sixteen sites on the main branch and two tributary sites in the Raquette River basin. DNA was isolated from mussel foot tissue in an attempt to identify patterns of gene flow by looking at polymorphic alleles in the Raquette River E. complanata population.

Although the use of RAPD primers proved problematic, micro-satellite primers fashioned for species of the Lampsilis genus have provided indications that they can be used to answer our questions regarding gene flow

Leitch, Amanda (2004) Human kinship recognition through olfaction of a canine

Abstract: The overall objective of this study was to assess the specificity of the olfactory cues that canines use when identifying humans. That is, once a dg is trained to identify the smell of a human (the target), will the dog be confused by the smell of the target’s siblings? A spayed golden retriever, less than two-years-old, was trained to pick her owner’s scent out of three possible choices. After a trial had been initiated by “go” the dog would smell each of three boxes containing T-shirts impregnated with human scent. The boxes were constructed such that the dog could not use visual cues. The dog signaled recognition of the target’s smell by a sit/stay response. The dog was trained to correctly identify the target over 90% of the time. When there was no target present the dog would repeatedly sample the three boxes and 80% of the time would not give the recognition signal. The dog was rewarded only for correct target responses. Probe trials consisting of the scent of the target’s siblings and no target scent were randombly inserted throughout the testing sessions. There was no reward given during a probe trial. Despite what other studies have shown, the dog did not give the recognition response more often to the smell of the target’s siblings as compared to the smell of non-related humans. Further testing is necessary to determine if there is any link between genetics (for instance HLA typing) and scent recognition.

Michaud, Cami (2004) In situ Hybridization Studies of Developmental Gene Expression in Postanatal Rat Brainstem

Abstract: Astrocytes have been hypothesized to mediate neuron controlled changes in ventilation by regulating extracellular pH in CO 2-sensitive respiratory centers of the brainstem through the activity of a sodium bicarbonate cotransporter (NBC), NBC 1. According to the proposed hypothesis, NBC 1 molecules pump bicarbonate ions from the extracellular space into the cytoplasm of astrocytes. Removing bicarbonate ions from the extracellular space would cause a decrease in extracellular pH, stimulating neurons in the CO 2-sensitive respiratory centers. The goal of this study was to determine the expression of NBC 1 and NBC 2 by astrocytes in the nucleus tractus solitarii (NTS), a CO 2-sensitive region of the brainstem. In situ hybridization was used to detect the presence of NBC 1 and NBC 2 mRNAs, as well as the mRNAa that are present in astrocytes for glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS), and neurofilament light (NFL) that are present in neurons. Probes labeled with either fluorescein, Texas-Red, BODIPY TMR, or BODIPY 630-650 were visualized using either a confocal or epifluorescent microscopy. The results of this study indicate 1) that NBC 1 and NBC 2 mRNAs occur in a wide variety of cells within the brainstem, 2) that astrocytes both inside and outside of CO 2-sensitive respiratory centers express NBC1, and 3) that neurons in the brainstem may also express GFAP, GS, NBC 1 and NBC 2 mRNA.

Miner, Stephanie S. (2004) Effects of Early Maternal Separation on Subsequent Maternal Behavior in Sprague Dawley Rats

 Abstract: This study was designed to assess how early maternal separation influences subsequent maternal behavior in rats. It was hypothesized that females separated from their mothers as pups would show deficits in maternal behavior as adults. Female Sprague-Dawley rats were separated from their mothers for 8-hr (long term/LT), 4-hr (short term/ST), or 0-hr (control/C). At maturity, subjects were mated, and following parturition, litters were culled to 2 male and 2 female pups on postnatal Day (PND) 1. Maternal behavior testing began on PND 2 and continued for 16 days. Lactation performance (pup weight change), nest building, maternal aggression, grouping, and hovering were examined. Analysis of variance and t-tests revealed that LT subjects used significantly more cotton and built higher quality nests than other groups. Also, LT subjects took significantly less time than C subjects to group their young. There was no effect of maternal separation on lactation performance, maternal aggression, or hovering, and, as expected, maternal behavior decreased across all variables as the weining time approached. Additional analyses revealed that LT females delivered significantly more pups than C females (p<0.05) and somewhat before C females (p=.071). Further research on these parameters is warranted. Contrary to the hypotheses, these results reveal that early maternal separation may, in fact, exaggerate some aspects of maternal behavior.

Ndungo, Esther (2004) A Method to Evaluate Ontogenetic Changes in Gene Expression of Glial Cells and Neurons Using RNase Protection Assays

Abstract: The goals of this research project were 1) to develop protocols for an RNase protection assay (RPA) to simultaneously measure levels of gene expression for glia, neuron, and key pH regulatory proteins of the rat brain, and 2) to follow the ontogenetic expression of these genes during postnatal development of 4, 11, 22, and 38 day old rats. The protocols developed during this project will be used to help evaluate the hypothesis that astrocytes in the medulla mediate ventilatory responses to CO 2 using pH regulatory molecules, including sodium bicarbonate cotransporter 1 (NBC1). Partial mRNA sequences for eight different proteins, four pH regulators, NBC 1, NBC 2, monocarboxylate transporter 1 (MCT 1), and MCT 2, three astrocyte markers, glial fibrillary acidic protein a (GFAP a), GFAP d, and glutamine synthetase (GS), and a neuronal marker, neurofilament light (NF-L) from the brainstem of 22 day old rats were obtained by reverse transcription-polymerase chain reaction (RT-PCR). RT-PCR products were cloned into a vector DNA and sequenced. Plasmid constructs were used as template for in vitro transcription reactions to generate antisense RNA probes and RNA control sequences for RPA. The constructs and protocols developed during this study can then be used to examine gene expression in different regions of the brainstem from rats of different ages.

Putney, Emily (2004) The Effects of Aging on Olfactory Ability

 Abstract: Although an age related decling in olfactory ability has been previously documented, the effect of aging specifically on odorant quality perception has been difficult to asses since there is an interaction between the intensity and quality components of olfactory perception. Thus the present study was designed to test the hypothesis that aging, in some way, changes olfactory quality perception independently of changes in odor intensity. Correcting for the subject to subject intensity discrepancy was accomplished by developing an isointensive odor set for each subject. Once the subject specific odorant set had been produced, dissimilarity ratings of common odor pairs were subjected to Multi-Dimensional Scaling Analysis from which it appeared that the young and elderly were clustered in different psychophysical spaces. Therefore, the data was consistent with the hypothesis that there is a change in the olfactory perception of elderly people, as compared to the young, that is independent of odorant intensity. The data also indicated that this change may be due to an alteration in both the trigeminal and olfactory systems.

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