Biology Commons^™

Feasibility Of Stocking Grass Carp (Ctenopharyngodon Idella; Cyprinidae) To Control Hydrilla (Hydrilla Verticillata; Hydrocharitaceae) In Lake Anna, Virginia, Paul Matthew Overton

Master's Theses

The goal of this study was to demonstrate the feasibility of using triploid ·Ctenopharvngodon idella (grass carp) to control Hydrilla verticillata in the Waste Heat Treatment Facility (WHTF) in Lake Anna, Virginia. The four objectives were to determine: the frequency of occurrences of grass carp over hydrilla; the proportions of hydrilla to other aquatic macrophytes in the guts of grass carp; effects of physical and chemical factors on movement of grass carp; and a theoretical stocking rate of grass carp for the WHTF. Frequency of occurrence of grass carp over hydrilla was calculated to be 84% and correlated with impoundment …

Characterization Of A Newly Cloned Dna Damage- Inducible Gene From Saccharomyces Cerevisiae Strain D43, June-Home Chen

Master's Theses

The identification and characterization of DNA damage-inducible genes is an important topic in the study of the integrity of the cellular genome. Previously, a TnlO-lacZ derivative was inserted randomly into yeast cells and the resulting mutants were screened for insertions in DNA damage-inducible genes. S. cerevisiae strain D43 was identified as one such TnlO-lacZ insertion mutant. DNA sequencing results show the insertion in D43 is located within the TDH2 gene, which encodes glyceraldehyde-3-phosphate dehydrogenase. Treatment of strain D43 with DNA damaging agents and heat shock suggest TDH2 is responsive to DNA damage, but not to heat shock. Haploid mutants carrying …

Leptodactylus Silvanimbus (Amphibia: Anura: Leptodactylidae): Natural History Notes, Advertisement Call, And Relationships, W. Ronald Heyer, Rafael O. De Sá, James R. Mccranie, Larry David Wilson

Biology Faculty Publications

In July 1995, we visited two of the three previously known localities for Leprodactylus silvanimbus in Departamento de Ocotepeque, Honduras. We found a new breeding site for the species, recorded its advertisement call, and collected and observed its adults and larvae. The purpose of this paper is to present the results of these new findings and to comment on the relationships L. silvanimbus.

Características De La Osificación Craneal En Phyllomedusa Boliviana (Anura: Hylidae), Rafael O. De Sá, E. O. Lavilla

Biology Faculty Publications

RESUMEN. Dentro de la familia Hylidae disponemos de información sobre las secuencias de osificación craneal para menos del 4.0% de sus miembros. El presente trabajo describe la secuencia de osificación craneal de Phyllomedusa boliviana. El patrón general de osificación es similar a lo reportado para otras especies de la familia, pero existen algunas diferencias importantes tales como la osificación tardía de los próoticos y la osificación premetamórfica de neopalatino, vómer, cuadrado-yugal, pterigoides y columela. El lento desarrollo ulterior de la osificación resulta en juveniles con cráneos extensamente cartilaginosos.

ABSTRACT. Characteristics of the cranial ossification in Phyllomedusa …

Hyla Multifasciata, Rafael O. De Sá

Biology Faculty Publications

Hyla multifasciata is a medium to large species in the albopunctata species group, adults ranging in size from 42 - 61 mm SVL (mean male SVL = 48 mm, mean female SVL = 53 mm). The head is longer than wide. The snout is rounded in dorsal view, whereas in lateral view it is rounded and protrudes slightly beyond the mandible. The canthus rostralis is rounded and distinct, the loreal region is concave, and the internarial region is convex. The eyes are large, approximately twice the diameter of the tympanum. The tympanum is separated from the eye by a distance …

The Effects Of Thyroid Hormone On Myosin Heavy Chain A-7 Production In Xenopus Laevis Tail And Leg Muscles, Andrew R. Noble

Honors Theses

The present research examines the expression of myosin heavy chain genes in muscle fibers in Xenopus laevis. Characteristically different muscle fibers are expressed before and after metamorphosis. The embryonic myosin proteins that are synthesized during the tadpole stages are replaced with adult myosin heavy chains at metamorphosis. At least one of the adult myosin genes, called A-7, is expressed only in the adult animals, not in tadpoles. The controlling factor or trigger for the expression of this adult gene still remains unknown. There are a number of possible explanations for the A-7 regulation at metamorphosis, including changes in particular hormone …

A Taxonomic Revision Of Neotropical Discocarpus (Euphorbiaceae), Sheila Mae Hayden

Master's Theses

This thesis is a taxonomic revision of Discocarpus, a genus of three species of trees from seasonally inundated forests of northern South America. Discocarpus is classified in the family Euphorbiaceae. The Euphorbiaceae or spurge family is a large and diverse taxon of angiosperms consisting of approximately 7000 species placed in 300 genera, comprising 49 tribes and 5 subfamilies (Webster 1994b). The origin of the family is likely Western Gondwanaland, and the earliest fossils identified as Euphorbiaceae date to the Paleocene (Raven & Axelrod 1974). The family is predominately tropical, however, species of Euphorbiaceae are important throughout most of the world …

Hyla Albopunctata, Rafael O. De Sá

Biology Faculty Publications

Hyla albopunctata is a medium-sized species in the albopunctata group, adults range in size from 42-52 mm SVL (males average 47 mm and females 49 mm). The head is triangular in outline, always longer than wide. The snout is moderately long and acuminate in dorsal view, whereas in lateral view, it is acuminate and protrudes beyond the mandible to form an angle of 45 degrees over the mandible. The canthus rostralis is rounded and distinct, the loreal region is slightly concave, and the internarial region is slightly convex. The eyes are large, approximately twice the diameter of the tympanum. The …

The Toxicity Of Cadmium To The Aquatic Amphibian, Xenopus Laevis, Sharon S. Millirons

Master's Theses

Cadmium toxicity is poorly understood but is a potentially serious environmental pollutant. This study was initiated to determine the effect of significant concentrations of cadmium on a readily available aquatic laboratory organism.

The lethal concentration (LC50) for 50 percent of I week old Xenopus laevis tadpoles was determined to be 0.1 ppm CdCI 2. For 5 week old animals, the average LC50 was determined to be 0.98 ppm. Thus, cadmium poses greater toxic threats to the early developmental stages. Moreover, these concentrations of cadmium exceed those commonly found in the nation's water supply. Histological examination suggested that the main site …

Phylogenetic Analysis Of Segment 10 From African Horsesickness Virus And Cognate Genes From Other Orbiviruses, Rafael O. De Sá, Marla Zellner, Marvin J. Grubman

Biology Faculty Publications

Utilizing the reverse transcriptase-polymerase chain reaction (RT-PCR) procedure, we have synthesized full-length copies of segment 10 from African horsesickness virus (AHSV) serotypes 1,4 and 8. The genes were cloned, sequenced and compared with the sequence of the cognate gene from AHSV serotypes 3 and 9. Sequences were analyzed to assess evolutionary relationships among serotypes using cladistics. Based on this analysis the data support a close relationship between serotypes 4 and 9 and between serotypes 1 and 8 and a closer relationship of serotype 3 to the 4 and 9 group.

Investigation Of Different Patterns Of Induction Of Amylases In Different Cultivars Of Rice, Oryza Sativa L., Angela M. Mosley

Master's Theses

This study investigated whether rice exhibits exceptions to the accepted model, in cereals, for the induction of a and P-amylase in the embryo and endosperm during germination. We also tried to establish whether different patterns of induction were cultivar specific, or due to the influence of ripening temperature, or a component of the incubation medium. An isoelectric focusing technique was used to monitor a- and P-amylase activities, a spectrophotometric assay was used to quantify the activity of a-amylase, and two cDNA clones, RAmy3D and RAmylA, were used to measure a-amylase RNA accumulation by Northern analysis. Distinct patterns of induction of …

Terrapene Carolina Carolina, Joseph C. Mitchell, Rafael O. De Sá

Biology Faculty Publications

TERRAPENE CAROLINA CAROLINA (Eastern Box Turtle). REPRODUCTION. Female Terrapene carolina containing oviductal eggs have been recorded in Virginia from 26 May to 25 July (Mitchell, in press. The Reptiles of Virginia. Smithsonian Inst. Press, Washington, D.C.). Other reports of reproduction in Terrapene (see list in Ernst and McBreen 1991. Cat. Amer. Amphib. Rept. 512.1-512.13) indicate that nesting occurs in late spring and early summer throughout its range.

What Are Squirrels Hiding, Michael Steele, Peter D. Smallwood

Biology Faculty Publications

The half-eaten acorns of squirrels are clues to their complex relationship with oaks. The special relationship between squirrels and acorns is examined.

Xenopus Laevis As A Model Organism, David C. Cannatella, Rafael O. De Sá

Biology Faculty Publications

Model organisms are often assumed to be representative of some more inclusive taxon of which the species is a part. This assumption leads to mistaken generalizations about the evolutionary and comparative significance of the data gathered. This paper reviews com? parative and evolutionary studies of Xenopus laevis and its relatives. Phylogenetic analysis of data from DNA sequences and morphology indicate that Xenopus is monophyletic and that Silurana is its sister group. The most basal lineages of Pipidae diverged prior to the breakup of Gondwana. The bizarre morphology of Xenopus is in part due to changes in the mode of meta? …

An Evaluation Of Hands-On Instruction As A Method To Improve Observation Skills In Second Grade Students, Lydia Rogers

Master's Theses

A hands-on assessment tool for testing second-grade students' ability to discriminate physical attributes (size, shape, color, texture, pattern, edge, part-to-whole, and type) of mollusk shells was developed, pretested, and administered to 48 second-grade students at Maybeury Elementary School, Henrico County, Virginia. Treatment group students (n = 24) attended five afterschool, activitybased classes in which close observation of object a~tributes was taught. The classes included the same discriminations as did the assessment test but used different materials. Control and test group students were retested. Neither paired t test nor question-by-question analysis showed a significant improvement in the test group's score. Presence …

Ribosomal Dna And The Phylogeny Of Frogs, David M. Hills, Loren K. Ammerman, Michael T. Dixon, Rafael O. De Sá

Biology Faculty Publications

Phylogenetic analysis of 1656 aligned sites in the 28S ribosomal RNA gene of frogs supports some of the recently recognized higher groups of anurans but provides counter-support for others. The 28S rDNA data support the monophyly of the recently recognized Pipanura (me- sobatrachians plus neobatrachians), which in turn indicates paraphyly of archaeobatrachians. Me- sobatrachians (pelobatoids plus pipoids), which are either considered paraphyletic or weakly sup- ported as monophyletic in morphological analyses, also receive support as a monophyletic group from the 28S rDNA data. Hyloidea (=Bufonoidea), which is widely recognized but lacks morphological support, receives some molecular support as being monophyletic. …

Relationships Of Epidermal Morphology And Breeding Behaviors In Pebble Nest-Building Minnows (Pisces: Cyprinidae), William R. Mcguire

Master's Theses

Abstrad The objective of this study was to determine if epidermal morphology corresponds with reproductive behavior in cyprinid fishes. Representative species of nest-building fishes (Nocomds leptocephalus, Semotilus atromeculatus, exoglossum maxillingua) and non nest-building fishes (Campostoma anomaulm and Clinostomus funduloides) were studied. Light and scanning electron microscopy were used to examine epidermal morphology and keratin distribution of skins from the snout, cheek, mandible, anterior dorso-lateral trunk, and caudal peduncle of breeding males of nest-building species and were compared to those in non nest-building cyprinid species. Previous frame-by-frame analysis of video tapes of reproductive activities of each species and literature accounts were …

Morfología Y Moléculas: Bases Complementarias De La Sistemática Moderna, Rafael O. De Sá, David M. Hillis

Biology Faculty Publications

RESUMEN

El auge de las técnicas moleculares en las últimas dos décadas ha traído nuevos enfoques en los estudios sistemáticos. Aquí presentaremos una revisión del uso, las aplicaciones, y los problemas de las principales metodologías de trabajo. Cada una de estas técnicas es aplicable a algunos problemas e inapropiada para otros, y es importante entender las suposiciones y limitaciones de cada técnica. Concluimos que el uso combinado de los enfoques morfológicos y moleculares otorga mejor resolución a los problemas sistemáticos.

ABSTRACT

The development of molecular techniques during the last two decades has brought new approaches to the analysis of systematic …

Localization Of A Collagenous Protein In The Organic Matrix Of Spicules From The Octocoral Leptogorgia Virgulata (Cnidaria: Gorgonacea), Jeffrey L. Dupree

Master's Theses

Calcareous body inclusions are commonly found throughout the invertebrate taxa. Elaborately structured calcium carbonate spicules are the major mineralized body inclusions of the gorgonian, Leptogorgia virgulata. Spicule formation in this octocoral, as well as other calcium carbonate invertebrate structures, is apparently regulated by the intra-spicule organic matrix. Recent findings show that the insoluble fraction of the spicule organic matrix is collagenous. Collagen, although integral to calcium phosphate structures found in vertebrates is not usually associated with the formation of invertebrate calcium carbonate structures. Interestingly, collagen is present in the organic matrix during the summer but absent in winter. This suggests …

Investigating The Viability Of Yeast Expressing Histone From Extrachromosomal Dna : Progress In Construction Of A Plasmid Bearing One Copy Of Each Yeast Histone Gene, Ralph Donaldson Hellams Jr.

Master's Theses

Much of the current information on histones has been based on in vitro studies. The original goal of this research was to construct a mutant strain of Saccharomyces cerevisiae containing all chromosomal copies of the yeast histone genes made nonfunctional. This project would demonstrate whether such a strain could be rescued by a plasmid carrying the wild-type copies of the four core histone genes. Furthermore, this yeast strain construct would allow future investigations to take advantage of histone mutant analysis in vivo. The critical step in beginning this work was the construction of a plasmid which contained the genes …

Atrial Natriuretic Factor In Meriones Unguiculatus, The Mongolian Gerbil, Kyriakos Tarasidis

Master's Theses

The basis for the great osmoregulatory ability in Meriones unguiculatus, the Mongolian gerbil, has been studied previously, but as yet no clear mechanism has been determined. The present study investigated the level of cardiac atrial natriuretic factor (ANF) under high and low sodium stress. In addition, cardiac ANF values for the Mongolian gerbil were compared with another desert mammal (Mesocricetus auratus, the Syrian golden hamster) and a non-desert mammal, (Rattus norvegicus, the white rat). ANF was found to exist in the hear atria of the Mongolian gerbil at a level of 388±66 µg ANF/g tissue. High and low sodium stress …

Vitello-Lipid And Vitello-Protein Deposition In Environmentally Stressed And Non-Stressed Populations Of Morone Saxatilis (Striped Bass), David Van Grimes

Master's Theses

Summer somatic indices of three and four year old striped bass (Morone saxatilis) from Lake Anna (LA), Virginia, a cooling water reservoir, indicated prey ingestion was not sufficient to maintain growth during summer months when striped bass metabolism was elevated by thermal and hypoxic stress. Vitello-lipid and vitello-protein concentrations of stressed LA striped bass were compared to those of non-stressed striped bass from Smith Mountain Lake (SML) , Virginia, a hydroelectric reservoir. Seasonal comparisons of LA and SML striped bass vitello-lipid concentrations and vitello-protein concentrations showed no significant differences between sites (P [less than or equal to] 0.05). Vitello nutrients …

Description Of The Tadpoles Of Gastrophryne Pictiventris And Nelsonophryne Aterrima (Anura: Microhylidae), With A Review Of Morphological Variation In Free-Swimming Microhylid Larvae, Maureen A. Donnelly, Rafael O. De Sá, Craig Guyer

Biology Faculty Publications

The tadpoles of Gastrophryne pictiventris and Nelsonophryne aterrima are described based on material collected in Costa Rica and Panama, respectively. The tadpole of G. pictiventris resembles those of the other species of Gastrophryne. The tadpole of N. aterrima differs from other New World microhylid tadpoles in location of the vent tube (medial), the spiracular opening (ventral to the gut), and eyes (dorsolateral). The unique configuration of mouthparts in N. aterrima is described. Morphological variation in microhylid tadpoles is reviewed and six larval characters are analyzed cladistically for IO New World microhylid genera.

Seasonal Fluctuations Of Thermophilic And Psychrophilic Bacteria In Westhampton Lake, Richmond, Virginia, Chukwukere Godwin Durunna

Master's Theses

This study was based on the hypothesis that the populations of thermophilic, mesophilic, and psychrophilic bacteria in Westhampton Lake vary seasonally and are related to prevailing temperatures. It may be inferred that the kinds of bacteria present at a given season are those most directly involved in decomposition and recycling activities in the lake. Water samples were collected biweekly from September of 1986 through mid- August 1987 at three stations in Westhampton Lake. At each station, sample depths ranged from near the surface to near the bottom. Serial dilutions were plated in duplicate on nutrient agar and were incubated at …

Frequency Of Rickettsia Sps. In Dermacentor Variabilis And Amblyomma Americanum In Central Hanover County, Virginia, Peggy Ann Keefe

Master's Theses

In the eastern United States, Dermacentor variabilis is the primary vector of Rickettsia rickettsii, the etiological agent for Rocky Mountain Spotted Fever. Cases of Rocky Mountain Spotted Fever in eastern United States increased steadily from 1959 to 1979 to a peak of one case per 200,000 people in 1979 (Morbidity and Mortality Weekly Report, 1985). In 1976, 98.9% of the reported cases of Rocky Mountain Spotted Fever were east of the 100th meridian with 1.1% occurring west of the 100th meridian (Burgdorfer, 1977). Hanover County, Virginia is an endemic area for this disease (Sonenshine, 1971); the last reported case was …

Pebble Nest Microhabitats Of Semotilus Species (Pisces: Cyprinidae), James Timothy Magee

Master's Theses

The pebble nest microhabitats of four species of Semotilus were compared. Pit/mound nests of Semotilus corporalis were significantly larger than the pit/ridge nests of Semotilus atromaculatus, Semotilus lumbee, and Semotilus thoreauianus. Nests of S. corporalis were in wider and deeper streams. Pits of S. lumbee nests were longest of the four species; those of S. corporalis were widest and deepest. Semotilus corporalis used a greater proportion of larger stones (23 mm or greater) in nest construction than the other three species. There was no significant difference in the electivity index (percentage of nest pebble sizes versus those of the substrate) …

Regulatory Cell Biology Of Growth Hormone And Prolactin In The Cow Mammary Gland, David Andrew Walkup

Master's Theses

Prolactin (PRL) acts directly on milk secretory cell nuclei to stimulate lactation in rats. In the cow, PRL has been detected in Golgi apparatus, endoplasmic reticulum, and secretory vesicle subcellular fractions of mammary gland , but not nuclear fractions. However, growth hormone {GH) is the galactopoeitic hormone in cows, not PRL. The possibility of GH acting directly on the cow milk secretory cells, and PRL acting on their nuclei was investigated using an immunocytochemical method. PRL and GH were detected in endoplasmic reticular and Golgi apparatus regions of the milk secretory cells, as well as, on nuclear and fat globule …

Use Of Solid-Phase Resins In Pesticide Monitoring, Jenny Bittinger

Honors Theses

The feasibility of using solid-phase resins for monitoring concentrations of pesticides in water was examined. Efforts were made to ascertain relationships between concentrations of a pesticide (methoxychlor) in water and on a resin (AXD-2) under laboratory conditions. Solutions of pesticide in water were drawn through columns of resin. Methylene Chloride was used to absorb the pesticide from the resin. Gas chromatography and ultraviolet spectrophotometry were used to measure concentrations of pesticide.

A Reverse Genetics Approach For Studying Histone H4 Structure-Function Relationships In Yeast, Michael J. Bonaduce

Master's Theses

A previously constructed mutation of the histone H4 gene has been the subject of a detailed analysis. The mutation involves an H4 gene encoding two amino acid changes which substitute aspartic acid for glycine at positions 13 and 42 of the polypeptide. These substitutions result in a nonfunctional H4 protein when assayed in Saccharomyces cerevisiae. In contrast, an analysis of an amino terminal deletion of amino acids 3-26 results in a functional H4 protein. Physical biochemistry studies identify the sites of histone-histone interactions between residues 38-102 of histone H4, the same area in which position 42 resides. The question being …

A Rapid System For Analyzing Histone H4 Mutations In The Yeast Saccharomyces Cerevisiae, Edward Rex Lakey Harkrader

Master's Theses

Genetically engineered, specific histone H4 mutations have been analyzed in yeast which lack normal H4 protein using the time consuming technique of tetrad dissection. The purpose of the present research project has been to develop a rapid new system for analyzing histone H4 mutations in yeast. The new system has made it possible to isolate quickly cells which are surviving on mutant H4 only. The system will make it possible to analyze more quickly large numbers of H4 mutations. It is termed a plasmid shuttle system because of the use of plasmid vectors for shuttling histone H4 alleles in and …