Life Sciences Commons^™

A Profile Of Antibiotic Resistant Bacteria In The James River, Keith Allen Boisvert

Master's Theses

Spatial and temporal variability in the antibiotic resistance of bacterial assemblages in the lower portion of the James River was examined. The antibiotic resistance of culturable coliforms was compared to the resistance in the microbial community. Antibiotic resistance was determined via colony formation on media containing antibiotics. The antibiotics ampicillin, chloramphenicol, streptomycin and tetracycline were used at concentrations ranging from 10 to 500 ug/ml. Statistically significant differences in the mean number of antibiotic resistant isolates were observed among both sample sites and dates. The sampling site at river mile 99 just below Richmond showed both increased antibiotic resistance and bacterial …

Semipermeable Membrane Devices Are Effective Surrogates Of Fish In Concentrating Polychlorinated Biphenyls, Christopher Gardner Collins

Master's Theses

This study examined the effectiveness of Semipermeable Membrane Devices (SPMDs) as surrogates for fish in concentrating polychlorinated biphenyls. Golden shiners (Notemigonus crysolucas) and SPMDs were exposed to three different concentrations (0.5, 1.5, and 3.0ppm) of Aroclor 1254 for 1, 3, and 5 days under laboratory conditions. Concentrations of Aroclor 1254 were measured in the SPMDs and fish tissue using extraction techniques and gas chromatography. The concentrations of PCB in SPMDs and N. crysolucas were positively correlated. This relationship compared favorably with data from other studies. The relationship between the concentration of PCB in SPMDs and tissue offish and …

Revision Of The Cerrado Hemicryptophytic Chamaesyce Of Boissier's "Pleiadeniae" (Euphorbiaceae), Mark P. Simmons, W. John Hayden

Biology Faculty Publications

The species of Chamaesyce classified by Boissier as the "Pleiadeniae'" are revised in light of presently available collections. Six species are accepted and new combinations are proposed for C. nana, C. setosa, C. tamanduana, and C. viscoides. Although these herbaceous perennials of cerrado vegetation of Brazil, northern Argentina, and adjacent countries are distinctive ecologically and geographically, cladistic analysis does not support their recognition as a monophyletic group.

Exercise The Power Of The Purse With Hussein, Porcher L. Taylor Iii

School of Professional and Continuing Studies Faculty Publications

In the same shrewd diplomatic spirit displayed by the Pentagon in its recent purchase of a squadron of MIG-29 fighter jets from Moldova in order to preempt the sale of the planes to Iran, the U.S. should offer to buy Iraq's entire biochemical weapons arsenal and then destroy it in place. Let's call this emerging instrument of U.S. foreign policy "preemptive economic diplomacy."

The Stabilizing Efects Of Disulfide Bonds On Limulus And Octopus Hemocyanin, Danielle Mercatante

Honors Theses

Hemocyanin is a large molecular weight, oxygen carrying protein that is present in the hemolymph of mollusks and arthropods . Limulus, horseshoe crab, hemocyanin is made up of 48 hexamer subunits ( consisting of seven different repeating subunits) each of which have oxygen binding dinuclear copper active centers. Octopus hemocyanin is composed of a single kind of polypeptide chain that has seven functional units, or oxygen binding domains.

The goals of research conducted by Gregory Cole and Danielle Mercatante during the fall of 1996 and spring of 1997 were to gain a biochemical understanding of the structure of Limulus and …

Assignment Of Fragile Site 8e (Fra8e) To Human Chromosome Band 8q24.11 Adjacent To The Hereditary Multiple Exostoses 1 Gene And Two Overlapping Langer-Giedion Syndrome Deletion Endpoints, April L. Hill, Y. Harada, E. Takahashi, J. Hou, M. J. Wagner, D. E. Wells

Biology Faculty Publications

The distamycin A inducible fragile site, FRA8E, Fra(8) (q24.11) has been previously mapped to 8q24.11, proximal to the MYC gene, by fluorescent in situ hybridization (Takahasi et al., 1991). This fragile site has been shown to be present in about 1 out of every 140 healthy Japanese individuals (Takahasi et al., 1988). To more precisely map FRA8E, we have used cosmids isolated from the Langer-Giedion chromosomal region (LGCR) for FISH analysis. Langer-Giedion syndrome (LGS) is a contiguous gene syndrome characterized by chromosome deletions in Sq24.11 (Ludecke et al., 1991). One of the genes known to be involved in the etiology …

Description Of Tadpoles Of Three Species Of Scinax (Anura: Hylidae), Rafael O. De Sá, Rocjard Wassersig, Arturo I. Kehr

Biology Faculty Publications

Larval morphological characteristics have been used to cluster species of Scinax in seven species groups and to support the monophyly of some of these groups. However, our present knowledge of Scinax tadpoles is incomplete; currently, tadpoles of only 21 of the approximately 80 recognized species have been described. Herein, we describe and illustrate the external morphology and oral disc characteristics of larval Scinax berthae, S. nebulosa, and S. boesemani. The presence of a "labial arm" supporting the P3 tooth row in S. boesemani, and its absence from S. nebulosa, is discussed in the light of our limited knowledge of tadpoles …

Description Of The Tadpole Of Atelopus Tricolor, E. O. Lavilla, Rafael O. De Sá, Ignacio De La Riva

Biology Faculty Publications

Tadpoles of Atelopus belong to the gastromyzophorous guild of exotrophic larvae (Altig and Johnston, 1989), and are characterized by the presence of a conspicuous abdominal sucker and an expanded oral disc. The larvae of several Atelopus species have been described previously: A. varius (Starrett, 1967); A. certus, A. ignescens, and A. spumarius (Duellman and Lynch, 1969); A. cruciger (Mebs, 1980); A. flavescens (Lescure, 1981); A. peruensis (Gray and Cannatella, 1985); and A. subornatus (Lynch, 1986). These represent about 15% of the known species in the genus (Frost, 1985; Duellman, 1993). Although Atelopus tricolor was originally described at the beginning of …

The Tadpole Of Pseudis Minuta (Anura: Pseudidae), An Apparent Case Of Heterochrony, Rafael O. De Sá, Esteban O. Lavilla

Biology Faculty Publications

The external morphology, oral disc, and coloration pattern of the larva of Pseudis minuta are described. Tadpoles are mostly bottom dwellers that have a small, terminal oral disc with a labial tooth row formula 1(1-1)/(1-1)2. Internal oral anatomy is characterized using scanning electron microscopy, representing the only description available for the family Pseudidae. The coloration pattern of P. minuta tadpoles is compared with that of other pseudids. Pseudis minuta larvae do not exhibit the ontogenetic coloration change reported for P. paradoxa. Considering larval coloration, larval size, and reports of adult size, acceleration or hypermorphosis are suggested as possible heterochronic mechanisms …

Internal Oral Anatomy: A Comparative Analysis Of The Phyllomedusinae (Anura:Hylidae), Erin B. Hines

Honors Theses

The internal oral anatomy of phyllomedusines has only been described for Agalychnis callydrias using light microscopy. Herein, we compare the internal oral anatomy of the genera Phyllomedusa, Agalychnis, Pachymedusa, and Phasmahyla, using SEM methodology. Tadpoles of ten species were prepared using standard SEM techniques; these larvae ranged from Gosner stages 34-39. Phasmahyla has a unique prenarial arena with three well developed pre-narial arena papillae, whereas the other genera possess the prenarial arena papillae in a semicircular arrangement with the opening directed posteriorly. Pachymedusa differs from Phyllomedusa and Agalychnis by having a low, straight-edge, median ridge; also, its buccal floor arena …

Ubiquitin-Mediated Proteolysis During Gametogenis In Chlamydomonas Reinhardtii, Hall Thomas Mcgee

Honors Theses

Scientists in the field of cell biology have focused considerable attention on a unicellular species of green algae known as Chlamydomonas reinhardtii. This organism is relatively common in bodies of fresh water and some types of soil, but most of the attention is due to its value as a model for biochemical studies. This laboratory has undertaken a broad study of the species including exploration into a special class of proteins, called heat shock proteins, and certain biochemical processes of the organism. The work herein described is a part of this latter study, and also a preliminary step in a …