Digital Commons Network^™

Isolation And Fusion Of Cotton Protoplasts, Michael H. Renfroe, Ronald C. Hartwig, Roberta H. Smith

Virginia Journal of Science

Protoplasts were isolated from five species of Gossypium. Protoplast yield and viability were affected by incubation conditions, osmolarity, purification procedures, and cell source. Using an optimized procedure, highly viable protoplasts were isolated from cell suspensions, callus cultures, and leaf tissue of G. hirsutum, G. arboreum, G. klotzschianum, G. harknessii, and G. herbaceum. Protoplasts of G. harknessii were enucleated and successfully fused with protoplasts of G. hirsutum.

Orientation In Complex Odor Landscapes: Spatial Arrangement Of Odor Sources Influences Crayfish Food Finding Efficiency In Artificial Streams, Troy Keller

Faculty Bibliography

Fluid dynamics has been shown to alter ecologically important behaviors of aquatic organisms orienting to distant chemical sources. Because the fluid dynamics and chemical plumes change across hydraulic environments, it is unclear which of these factors influence orientation behavior more. This study examined how alterations in chemical signal structure, through changes in source spatial arrangement, affect chemically mediated search behavior. Microelectrochemical measurements of tracer molecules revealed that source arrangement significantly alters the downstream fine-scale structure of chemical plumes. Flume hydrodynamic characterizations (as measured with laser Doppler velocimetry) also differed among source arrangements; however, differences were minor and existed only at …

Analysis Of E. Coli Dna From Selected Source(S) Using Pulsed-Field Gel Electrophoresis, Sheema Doshi

Theses, Dissertations and Capstones

The presence of fecal coliforms in surface waters is a public health issue throughout the United States and Canada. The presence of Escherichia coli (E. coli) indicates recent fecal contamination from either animal or human sources. To solve this growing problem one must identify the source(s) of such contamination by creating a database of DNA profiles of£. coli isolates. Hence, tracking the source(s) of E. coli can help link water contamination to animal source(s) of contamination. In this study, pulsed field gel electrophoresis (PFGE) was used to analyze DNA from E. coli isolates from known animals. For PFGE, the bacterial …

Ethnic Differences In Risk From Mercury Among Savannah River Fishermen, Joanna Burger, Karen F. Gaines, Michael Gochfeld

Faculty Research & Creative Activity

Fishing plays an important role in people's lives and contaminant levels in fish are a public health concern. Many states have issued consumption advisories; South Carolina and Georgia have issued them for the Savannah River based on mercury and radionuclide levels. This study examined ethnic differences in risk from mercury exposure among people consuming fish from the Savannah River, based on site-specific consumption patterns and analysis of mercury in fish. Among fish, there were significant interspecies differences in mercury levels, and there were ethnic differences in consumption patterns. Two methods of examining risk are presented: (1) Hazard Index (HI), and …

Description Of Hakka, A New Genus Of Jumping Spider (Araneae, Salticidae) From Hawaii And East Asia, James W. Berry, Jerzy Prószyński

Scholarship and Professional Work - LAS

We describe a new genus for a jumping spider that was originally placed in the large genus Menemerus Simon 1868, from which the new genus is clearly different. They were later reclassified as Icius, then as Pseudicius, and still later as Salticus. These initial classifications were repeated by a number of authors. The distinctive features of the male, and somewhat ambiguous features of the female, do not fit any known genus; and this species is here assigned to the new genus Hakka.

Leptin Activates Anorexigenic Pomc Neurons Through A Neural Network In The Arcuate Nucleus, Michael A. Cowley, James L. Smart, Marcelo Rubinstein, Marcelo G. Cerdan, Sabrina Diano, Tamas L. Horvath, Roger D. Cone, Malcolm J. Low

Faculty Publications - Department of Biological & Molecular Science

The administration of leptin to leptin-deficient humans, and the analogous Lepob/Lepob mice, effectively reduces hyperphagia and obesity. But common obesity is associated with elevated leptin, which suggests that obese humans are resistant to this adipocyte hormone. In addition to regulating long-term energy balance, leptin also rapidly affects neuronal activity. Proopiomelanocortin (POMC) and neuropeptide-Y types of neurons in the arcuate nucleus of the hypothalamus7 are both principal sites of leptin receptor expression and the source of potent neuropeptide modulators, melanocortins and neuropeptide Y, which exert opposing effects on feeding and metabolism. These neurons are therefore ideal for characterizing leptin action and …

Nitric Oxide And Cnidarian-Dinoflagellate Symbioses: Pieces Of A Puzzle, Henry G. Trapido-Rosenthal, Katherine H. Sharp

Arts & Sciences Faculty Publications

The presence of nitric oxide synthase (NOS) activity is demonstrated in the tropical marine cnidarian Aiptasia pallida and in its symbiotic dinoflagellate algae, Symbiodinium bermudense. Enzyme activity was assayed by measuring the conversion of arginine to citrulline. Biochemical characterization of NOS from Aiptasia was characterized with respect to cellular localization, substrate and cofactor requirements, inhibitors, and kinetics. In response to acute temperature shock, anemones retracted their tentacles. Animals subjected to such stress had lower NOS activities than did controls. Treatment with NOS inhibitors caused tentacular retraction, while treatment with the NOS substrate L-arginine inhibited this response to stress, as did …

Fisheries Occasional Publication No. 31 - Feeding Lupins To Fish: A Review Of The Nutritional And Biological Value Of Lupins In Aquaculture Feeds, Brett Glencross

Fisheries Occasional Publications

Lupins are the harvested seed of species from the Lupinus genus, a group within the leguminous bean and pea family Fabaceae. Legumes are particularly valuable agricultural crops because of their capacity to provide a grain crop and also fix and return nitrogen to soils and improve the soil value for further cropping. The oilseeds, soybeans and peanuts are also leguminous plants, though traditionally they have been cropped for their oil value, whereas lupins, are cropped for both their protein and nitrogen fixing value (Gladstones, 1998; Perry et al., 1998).

The three key commercial species of lupins are L. angustifolius (Narrow-leafed …

Using Upper Boundary Constraints To Quantify Competitive Response Of Desert Annuals, Laura M. Lessin, Andrew R. Dyer, Deborah E. Goldberg

Faculty Publications

Using a target-neighborhood approach with six annual dicot species in the Negev Desert of Israel, we tested whether neighborhood biomass constrained the upper limit of plant performance and if the slope of the upper boundary was correlated to species trait means, such as relative growth rate (RGR) and seed mass. Target individuals were measured in early spring and then collected at the onset of the dry season along with all naturally occurring neighbors within a 5-cm radius of the target. Using a minimum of 50 samples for each of the six target species, we found no significant relationships between target …

Effects Of High Dietary Protein And High Energy Density On Gastric Evacuation And Return Of Appetite In The Rainbow Trout, Oncorhynchus Mykiss, Ahmet Adem Teki̇nay, Yusuf Güner

Turkish Journal of Biology

Rainbow trout (Oncorhynchus mykiss) were fed diets containing three different concentrations of crude protein (56.3%, 51.7% and 45.8%) and digestible energy (21.3, 20.3 and 18.8 MJ/kg), and the effects of dietary protein and energy level on gastric evacuation and return of appetite times were investigated. Gastric evacuation determinations were achieved by slaughtering 8 fish every 6 hours until no residue was found in the cardiac stomach of fish. Return of appetite experiments were conducted by re-feeding groups of trout every 4 or 6 hours following the first feeding. The data obtained from each process was modelled by regression analysis and …

Production Of Single-Cell Protein From Ram Horn Hydrolysate, Esabi̇ Başaran Kurbanoğlu

Turkish Journal of Biology

Candida utilis NRRL Y-900 was grown on horn hydrolysate for single-cell protein production. First, ram horns obtained from slaughterhouse in Erzurum were hydrolyzed by physical and chemical methods and crude horn hydrolysate (CHH) was obtained. The contents of protein, nitrogen, ash, some minerals, total sugars and amino acids of CHH were determined and it was seen that it has sufficient organic and inorganic materials to allow its use as a substrate source in the production of single-cell protein. The CHH was enriched by addition of yeast extract, glucose and KH_2PO_4. The effects of different CHH concentrations (1, 2, 3, 4, …

Acclimation To Hypoxia Increases Survival Time Of Zebrafish, Danio Rerio, During Lethal Hypoxia, Bernard B. Rees, F Sudradjat, J W. Love

Biological Sciences Faculty Publications

Survivorship of zebrafish, Danio rerio, was measured during lethal hypoxic stress after pretreatment in water at either ambient oxygen or at a lowered, but nonlethal, level of oxygen. Acclimation to nonlethal hypoxia (pO2 @ 15 Torr; ca. 10% air-saturation) for 48 hr significantly extended survival time during more severe hypoxia (pO2 @ 8 Torr; ca. 5% air-saturation) compared to survival of individuals with no prior hypoxic exposure. The magnitude of the acclimation effect depended upon the sex of the fish: hypoxia pretreatment increased the survival times of males by a factor of approximately 9 and that of females by a …

Renal Function In Suckling And Fasting Pups Of The Northern Elephant Seal, Dorian S. Houser, Daniel E E. Crocker, Paul M. Webb, Daniel P. Costa

Arts & Sciences Faculty Publications

Elephant seals fast for prolonged periods without access to water. This is made possible, in part, by reductions in urine production. However, the mechanisms involved in reducing urine production are not understood. In this study, glomerular filtration rate (GFR) was measured in five northern elephant seal pups (Mirounga angustirostris) via the inulin clearance technique. Measurements were made during day 9 and day 18–22 of nursing and the second and eighth week of the postweaning fast. Plasma aldosterone and cortisol concentrations, quantified by radioimmunoassay, were measured in eight other weanlings during the second and eighth week of the fast. …

A Comparative Study Of The Feeding Ecology Of Chelonia Mydas (Green Turtle) And The Incidental Ingestion Of Prorocentrum Spp, Karen Gayle Holloway Adkins

Retrospective Theses and Dissertations

The diets of green turtles from five dissimilar aggregations of juvenile C. mydas on the East Coast of Florida were analyzed. C. mydas were captured by tangle net from four of the study sites and a dietary sample was collected by an esophageal flushing technique. The gut content of stranded individuals was collected for the fifth site. The vegetation in these study areas differs in varying degrees of abundance and diversity. Analysis of the samples revealed the alga types preferred by green turtles from each population and provided the basis for examination of similarities and differences in their diets.

Large …

Hemin-Binding Surface Protein From Bartonella Quintana, James A. Carroll, Sherry A. Coleman, Laura S. Smitherman, Michael F. Minnick

Biological Sciences Faculty Publications

Bartonella quintana, the agent of trench fever and a cause of endocarditis and bacillary angiomatosis in humans, has the highest reported in vitro hemin requirement for any bacterium. We determined that eight membrane-associated proteins from B. quintana bind hemin and that a similar to 25-kDa protein (HbpA) was the dominant hemin binding protein. Like many outer membrane proteins, HbpA partitions to the detergent phase of a Triton X-114 extract of the cell and is heat modifiable, displaying an apparent molecular mass shift from approximately 25 to 30 kDa when solubilized at 100 degreesC. Immunoblots of purified outer and inner membranes …

Cadmium Induced Gene Expression And Signal Transduction Pathway, Daisuke Maki

Masters Theses

Cells respond to cadmium (Cd), a common environmental contaminate, by potentially decreasing reduced intracellular glutathione, as well as, increasing the expression of several antioxidant genes. One of these antioxidant genes, glucose-6- phosphate dehydrogenase (G6PDH), is the rate limiting enzyme of the pentose phosphate pathway. This pathway produces NADPH which is used for maintenance of reduced glutathione so, it is hypothesized that Cd should increase G6PDH expression. In this study, we demonstrate that Cd increases the level of G6PDH mRNA in primary rat hepatocytes in culture. In the presence of the antioxidants, N-acetylcysteine (NAC), Trolox, or glutathione monoethyl ester an attenuation …

H-Ns Controls Pap And Daa Fimbrial Transcription In Escherichia Coli In Response To Multiple Environmental Cues, C. A. White-Ziegler, A. Villapakkam, K. Ronaszeki, S. Young

Biological Sciences: Faculty Publications

A comparative study was completed to determine the influence of various environmental stimuli on the transcription of three different fimbrial operons in Escherichia coli and to determine the role of the histone-like protein H-NS in this environmental regulation. The fimbrial operons studied included the pap operon, which encodes pyelonephritis-associated pili (P pili), the daa operon, which encodes F1845 fimbriae, and the fan operon, which encodes K99 fimbriae. Using lacZYA transcriptional fusions within each of the fimbrial operons, we tested temperature, osmolarity, carbon source, rich medium, oxygen levels, pH, amino acids, solid medium, and iron concentration for their effects on fimbrial …

Sequence Analysis Of Bacterial Dna In The Colon And Stomach Of The Tyrolean Iceman, Raul J. Cano, Friedrich Tiefenbrunner, Massimo Ubaldi, Clarissa Del Cueto, Stefania Luciani, Tobe Cox, Paula Orkand, Karl H. Kunzel, Franco Rollo

Biological Sciences

The male human body found in an Alpine glacier on September 19, 1991 ("Tyrolean Iceman") has, for the first time in history, given scientists a chance to perform detailed anatomical, histological, and molecular investigations on the organs of a person from the Neolithic Age (5350-5100 B.P.). In the present study, tissue samples aseptically taken from the stomach and the colon of the mummy were utilized for DNA extraction, and the DNA was PCR-amplified, using primer pairs designed to bind to fragments of the 16s ribosomal RNA gene (16s rDNA) of a broad range of bacteria. The PCR products were cloned …

Energetics Of Larval Swimming And Metamorphosis In Four Species Of Bugula (Bryozoa), Dean E. Wendt

Biological Sciences

The amount of energy available to larvae during swimming, location of a suitable recruitment site, and metamorphosis influences the length of time they can spend in the plankton. Energetic parameters such as swimming speed, oxygen consumption during swimming and metamorphosis, and elemental carbon and nitrogen content were measured for larvae of four species of bryozoans, Bugula neritina, B. simplex, B. stolonifera, and B. turrita. The larvae of these species are aplanktotrophic with a short free-swimming phase ranging from less than one hour to a maximum of about 36 hours. There is about a fivefold difference in larval volume …

A Biochemical Mechanism For Nonrandom Mutations And Evolution, Barbara E. Wright

Biological Sciences Faculty Publications

No abstract provided.

Effects Of Elevated Carbon Dioxide And Nitrogen Fixation On A Legume-Based System: A Test With Soybean And The Soybean Looper, Pseudoplusia Includens, Angela M. Spickard

Masters Theses

Wild-type and non-nodulated soybean were grown at 367 ± 10 ppm [ambient] and 756 ± 10 ppm [elevated] CO₂ to determine whether nitrogen fixation could minimize the effects of elevated CO₂ on plant nutritional and defensive chemistry. Relative to non-nodulated soybean, wild-type soybean had higher concentrations of leaf nitrogen and proteinase inhibitors, as well as lower C:N ratios and lower phenolics. Elevated CO₂ resulted in decreased leaf nitrogen and proteinase inhibitor contents, and increased C:N ratios and phenolics in both soybean strains. Constitutive levels of phenolics and proteinase inhibitors occurred as predicted by the Carbon/Nutrient Balance hypothesis …

Effects Of Forced Weaning On Mother-Daughter Associations And Reproduction In Bison (Bos Bison), Jennifer S. Brookshier

Biology

While the social organization of ungulates has received much attention, the nature and extent of the mother-daughter association is still not fully known for some species. In bison, mothers and daughters have a long-term association that may extend beyond the age of weaning. This association is believed to facilitate the daughters' social integration into the herd. I compared the mother-daughter association for 29 yearling females that were forcibly weaned from their mothers to that of 19 yearling females that were naturally weaned. Forcibly weaned yearlings did not reassociate with their mothers following winter separation, while naturally weaned yearlings associated with …

Sexual Dichromatism In Bohemian Waxwings, James Brian Burns

Biology

If a species of birds is monomorphic, how do individuals identify members of the opposite sex? Birds may use cues in the ultraviolet wavelengths (350-400 nm), which are invisible to humans. This thesis presents evidence of sexual dichromatism in Bohemian Waxwings (Bombycilla garrulus). The strongest differences occurred in the tail coverts, the yellow tail tips, and the red waxy tips of the secondaries. Like other birds, waxwings derive colors from diet-based pigments and from synthesized colors. Because these color types differ in origin, each could provide different visual information about a bird's condition. This led to the testing …

Effects Of Carbohydrate Foods On Foraging Decisions Of The Parasitoid Bathyplectes Curculionis (Thomson) (Hymenoptera: Ichneumonidae), Helen Spafford Jacob

Biology

In a series of field and laboratory experiments, I explored the trade-off between self-maintenance and current reproduction for the parasitoid Bathyplectes curculionis (Thomson)(Hymenoptera: Ichneumonidae), an economically important natural enemy of the alfalfa weevil, the most significant pest in forage alfalfa. Floral nectars, pea aphid honeydew, and artificial foods such as sugar sprays are likely to assist B. curculionis in meeting its self-maintenance needs. Once these needs are met then B. curculionis females may be more likely to search for hosts to parasitize. However, these foods must not only be available, but accessible, of high quality, and detectable, to be of …

The Utilization Of Steep Slopes By Desert Tortoises (Gopherus Agassizii) In The Western Mojave Desert, Ty J. Gardner

Biology

Desert tortoises (Gopherus agassizii) were located on steep slopes at three sites in the western Mojave Desert. These sites were located at: 1) the rifle range of the Marine Corps Logistics Base, Barstow, California, 2) the southern boundary of the Fort Irwin National Training Center, California, immediately west of Manix Tank Trail, and 3) the Lava Range of the Marine Corps Air Ground Combat Center, Twentynine Palms, California. Additionally, a valley site at the Sand Hill range of the Marine Corps Air Ground Combat Center, Twentynine Palms, California, was included for comparison. Study tortoises were found on slopes …

Integrating Development With Evolution: A Case Study With Beetle Horns, Douglas J. Emlen

Biological Sciences Faculty Publications

No abstract provided.

Molecular And Morphological Identification Of An Endophytic Fusarium Isolated From Wheat And Characterization Of Its Laccases In Comparison To Affiliated Fusarium Isolates, Sun Il Kwon

Biology

A fungal isolate present as a seed endophyte caused disease in wheat and other cereals when grown under stressed conditions. The isolate was identified as a member of the Asian clade of the Gibberella fujikuroi species complex in the genus Fusarium, members of which are known as plant pathogens and producers of mycotoxins. The closest relative to the fungus was Fusarium proliferatum, although none of the previously described species was identical in all morphological and molecular phylogenetic characters. At least six laccase isozymes were detected in mycelial extracts or from extracellular culture filtrates of the Fusarium-wheat isolate. …

An Ulstrastructural Study Of Acetabularia Acetabulum, Rachel Vangilder

Master's Theses

Calcification within the cell and the cell wall Acetabularia acetabulum, a large single cell alga, is examined through an ultrastructural investigation, electron diffraction, and an elemental analysis. These methods suggest that amorphous calcium carbonate is located adjacent to and within the cell wall. The location of the crystals within and directly outside the cell wall suggests the calcium is obtained from the surrounding environment. Fibrillar structures are seen through SEM in areas where calcification is occurring. This fibrillar material appears to serve as the organic matrix where calcification initiates. Intracellularly electron dense materials is seen in the chloroplasts. This …

Type I Nitroreductases In Soil Enterobacteria Reduce Tnt (2,4,6-Trinitrotoluene) And Rdx (Hexahydro-1,3,5-Trinitro-1,3,5-Triazine), Christopher Kitts, Chad E. Green, Rebecca A. Otley, Marc A. Alvarez, Pat J. Unkefer

Biological Sciences

Many enteric bacteria express a type I oxygen-insensitive nitroreductase, which reduces nitro groups on many different nitroaromatic compounds under aerobic conditions. Enzymatic reduction of nitramines was also documented in enteric bacteria under anaerobic conditions. This study indicates that nitramine reduction in enteric bacteria is carried out by the type I, or oxygen-insensitive nitroreductase, rather than a type II enzyme. The enteric bacterium Morganella morganii strain B2 with documented hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) nitroreductase activity, and Enterobacter cloacae strain 96-3 with documented 2,4,6-trinitrotoluene (TNT) nitroreductase activity, were used here to show that the explosives TNT and RDX were both reduced by a type …

Reflections On Science And Technology, Ursula Goodenough

Biology Faculty Research

Science and technology are frequently confused. This essay points out the bases for this confusion and then focuses on a basic distinction, namely, that whereas science brings us information that we have little choice but to absorb and reflect upon, technology is something that humans elect to do and, hence, can also elect not to do. It is proposed that technological ethics are most cogently undertaken with scientific understanding as the linchpin and religious/artistic sensibilities as the muse.