Biology Commons^™

Sodium/Proton Exchange In The Gills Of Three Species Of Crabs : Libinia Dubia, Callinectes Sapidus, And Menippe Mercenaria, Nicholas J. Maiolo

Master's Theses

Na+/H+ exchange was studied in plasma membrane vesicles from gills of three species of crabs: Callinectes sapidus (blue crab), Libinia dubia (spider crab), and Menippe mercenaria (stone crab). Spider crabs and stone crabs were acclimated to full (35ppt) seawater, while blue crabs were acclimated to both dilute (5ppt) and full strength seawater. Membrane vesicles were prepared by sucrose density centrifugation. Na+/H+ exchange was analyzed using acridine orange fluorescence. Male C. sapidus showed the most exchange activity (per g gill tissue), followed by M. mercenaria, female C. sapidus and Libinia dubia. No difference in exchange activity was evident when blue crabs …

Histology Of The Ovaries And Fat Bodies Of Chthonerpeton Indistinctum, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

Histological analysis revealed three different stages in the development of ovarian follicles of Chthonerpeton indistinctum. These stages are identified by (1) location of the oocyte in the ovary wall, (2) oocyte morphology and staining characteristics, (3) development of the zona pellucida, and (4) organization of the follicular layer. Atretic follicles and corpora lutea also were found. Fat bodies are composed of well-developed adipose tissue.

Some Chemical And Physical Factors Influencing Growth Of Panus Stipticus Bulliard Ex Fries And Armillariella Mellea (Vahl Ex Fries) Karsten, James Robert Kirkland

Master's Theses

Two species of wood rotting fungi were used to investigate the possibility that growth-enhancing or inhibitory substances in woods from various trees are responsible for the distribution of these fungi in nature. Panus stipticus (Bulliard ex Fries) and Armillariella mellea (Vahl ex Fries) Karsten were cultured in the laboratory on blocks of wood from Taxodium distichum (L.) Richard, Juniperus virginiana L., Pinus taeda L. and Quercus rubra L. Panus stipticus grew well on the surface of the wood blocks; histological studies showed less penetration into the xylem of the softwoods than into that of Q. rubra. Armillariella mellea grew well …

Age And Growth Of Black Crappie Pomoxis Nigromaculatus In Lake Anna, A Virginia Power Cooling Impoundment, Robert Mason Daniels

Master's Theses

A study of the age and growth of black crappie, Pomoxis nigromaculatus, was conducted in Lake Anna, Virginia, a cooling impoundment for Virginia Power's North Anna Power Station. Growth of the population in the reservoir was compared to that of the population in North Anna's Waste Heat Treatment Facility. Analysis of covariance (ANCOVA) using age as the covariate indicated the growth rate of the two populations did not differ significantly at the .05 level. The populations were combined and tests were conducted to determine differences in growth rates between the sexes. ANCOVA indicated the growth rates of males and females …

Sodium/Proton Exhange In Membrane Vesicles From Crab (Callinected Sapidus And Carcinus Maenas) Gill, Robert Eric Shetlar

Master's Theses

The existence of a sodium-ion-for-hydrogen-ion exchange mechanism in the membranes of certain epithelial cells has been demonstrated by many investigators (Murer et al., 1976; Tsai et al., 1984; Seiler et al., 1985 ) • This mechanism has been shown to exchange one Na+ for one H+ (Aronson & Igarashi, 1986) and is thought to be more prominent in the brush-border membranes (Murer et al., 197 6; Reenstra et al., 1981 ; Ives et al., 1983) of mammalian kidney tubules and intestinal tissues than in basolateral membranes of these tissues. The roles the exchanger plays in the cell may include intracellular …

Spermatogenesis And Histology Of The Testes Of The Caecilian, Chthonerpeton Indistinctum, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

Macroscopically, the testes of Chthonerpeton indistinctum consist of a series of oval lobes. The number and size of lobes is variable in Chthonerpeton indistinctum. Histologically, the testes are divided into structural units, locules separated by septa of connective tissue. Inside of each locule spermatogenesis takes place in cysts of germinal cells that divide synchronically. Chthonerpeton indistinctum is divided chronologically into four stages of development based on the shape of the nuclei of the spermatids and their arrangement in the cyst: (1) round, (2) kidney shaped, (3) attenuate, and (4) bouquet arrangement.

A Survey Of Cellular Slime Molds At Selected Sites On The James River, Virginia, Nathaniel Lemaster Armistead

Master's Theses

The flood plain of the James River in Virginia supports a variety of deciduous forest associations and has not been examined previously for dictyostelids. This thesis is primarily concerned with the results of a survey of dictyostelids at selected sites in the James River basin. Some incidental observations concerning possible ecological relationships between dictyostelids are included.

Seven of the plant communities of Virginia described by Harvill, Stevens and Ware (1984) afe present in the areas surveyed and collection sites were established accordingly: (1) Mountain Pine-Oak Heath, (2) Pine-Oak Heath, (3) Oak-Hickory Forest, (4) Alluvial Hardwood Forest, (5) Beech-Maple-Tuliptree Forest, (6) …

A Survey Of Cellular Slime Molds At Selected Sites On The James River, Virginia, Nathaniel Lemaster Armistead Iii

Master's Theses

Forty-three sample sites representing seven plant associations were surveyed for cellular slime molds in the James River basin from the head-waters to the mouth of the James River. Dictyostelium mucoroides, Q. minutum, Q. purpureum, D. discoideum, Polysphondylium violaceum and P. pallidum were found in all associations. Dictyostelium lacteum was found in all but the Maple-Basswood association. The remaining species were unique to the Alluvial Hardwood association and the following respective forest types: D. polycephalum to Oak-Hickory, D. giganteum to Oak-Hickory and Mixed Mesophytic, and D. rosarium to Mixed Mesophytic. A percentage similarity test indicated that, with regards to the observed …

Apid Increase In Serum Calcium In Response To Stress In Pomoxis Nigromaculatus, Black Crappie, Severn Borden Churn

Master's Theses

Serum calcium levels were determined colorimetrically in Pomoxis nigromaculatus, the black crappie, subjected to rapid changes in temperature. Two experiments were conducted; in the first, fish were exposed to stress for 30 minutes before measuring serum calcium, and in the second, fish were exposed to stress for 5 minutes and returned to normal conditions for 25 minutes before measuring serum calcium. Condit ion (K-value) and sexual development were noted for the fish. Serum calcium increased in all stressed fish, regardless of sex, but higher serum calcium values were observed in stressed mature females than in stressed males or stressed immature …

Genetic Engineering, W. John Hayden

Biology Faculty Publications

Why do so many biologists express so little concern for biology as a whole and such contempt for fields other than their own? The current debate on release of genetically engineered organisms into the environment, specifically, J. E. Fox's recent reply (Letters, 18 Oct., p. 237) to an earlier letter by R. K. Colwell et al. (12 July, p. 111), offers a case in point.

An Electrophoretic Analysis Of The Genetic Relationship Between Etheostoma Nigrum And Etheostoma Olmstedi (Percidae: Etheostomatini) In The James River Drainage Of Virginia, John Stuart Prince Jr.

Master's Theses

Etheostoma nigrum Rafinesque 1820, the Johnny darter ranges from Alabama to the Hudson Bay and from Colorado east to the Atlantic slope in the James, Roanoke, Tar and Neuse Rivers. Etheostoma olmstedi Storer 1842, the tesselated darter, is restricted to the east coast in the Atlantic and Lake Ontario drainage. In the James and Roanoke River systems in Virginia E. nigrum occupies the piedmont and montane regions whereas E. olmstedi primarily inhabits the coastal plain. The relationship between the morphologically similar species of darters (subgenus Boleosoma) is controversial and has been investigated by several authors. Stone (1947), using multiple character …

Anatomy And Systematics Of Penthorum L., Melanie Lynn Haskins

Master's Theses

The genus Penthorum L. consists of two species of perennial herbs, P. sedoides of eastern North America and P. chinense of eastern Asia. Penthorum has long be.en considered intermediate between crassulaceae and Saxifragaceae. An anatomical study of both species was undertaken to contribute to a better understanding of the relationships of these plants. Prominent anatomical features of Penthorum include: an aerenchymatous cortex and closely-spaced collateral vascular bundles of stems; one-trace unilacunar nodes; brochidodromous venation, rosoid teeth bearing hydathodes, and anomocytic stomata of leaves; angular vessel elements with many-barred scalariform perforation plates and alternate to scattered intervascular pits; thin-walled non-septate fiber-tracheids; …

Atp Defendent Na+ Transport And The Characterization Of Na+ / Nh4+ Exchange In Basolateral Vesicles Of The Blue Crab, Callinectes Sapidus, Gill, Linda Ann Fuhrman

Master's Theses

ATP dependent Na⁺ transport was denonstrated in purified ba.solateral vesicles of the blue crab (Callinectes sapidus) gill. Active Na⁺ uptake was dependent upon the intravesicular presence of either K⁺ or NH; as a counterion. Final membrane preparations consist of inside-out basolateral vesicles, evidenced by intravesicular ouabain (1 rrM) and extravesicular vanadate (1 rnM) ²²Na ⁺ uptake inhibition. Na⁺/NH₄⁺exchange rates were investigated by detennining the NH; concentration in the recovered extravesicular nedium and by using the kinetic capabilities of a DU7 spectrophotareter. These purified basolateral membranes, rich in Na⁺,K^{+ …}

The Effects Of Stress On The Blood Calcium Level In The Male White Rat (Rattus Norvegicus), Howard Perry Cobb

Master's Theses

THE EFFECTS OF STRESS ON THE BLOOD CALCIUM LEVEL IN THE MALE WHITE RAT (Rattus norvegicus) by Howard Perry Cobb I I I was writ ten as part of the requirements for a Master of Science degree in Biology at the University of Richmond (May, 1985). The present experiment was designed to determine whether parathyroid hormone (PTH) can be considered a "stress" hormone. Parathyroidectomized (PX) male rats (160-200 g) were injected with 10, 20, or 30 USP units of PTH per 100 g body weight and subjected to confinement/UHF stress for a 1.5-h period. Serum calcium levels of these PX …

Gametogenesis En Chthonerpeton Indistinctum (Gymnophiona: Typhlonectidae), Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

RESUMEN:

Histológicamente, las gónadas de Chthonerpeton indistinctum son similares a las ya descritas para otras especies del orden Gymnophiona. Los lóbulos testiculares se hallan compartimentados en unidades estructurales denominadas lóculos. La espermatogénesis ocurre en cistos sincrónicos de células germinales. Durante la espermiogénesis se identifican cuatro estados consecutivos de desarrollo: 1) cistos de espermátidas redondeadas; 2) cistos de espermátidas arrifionadas; 3) cistos de espermátidas bastoniformes y 4) espermátidas en ramillete.

El análisis histológico de los ovarios mostró la presencia de tres estados en la maduración de los folículos ováricos. Estas etapas pueden ser identificadas de acuerdo a: 1) ubicación del folículo …

Morfología Y Funciones Del Conducto De Müller De Chthonerpeton Indistinctum (Reinhardt Y Lutken, 1862) (Amphibia: Gymnophiona) En Relación Con Los Mecanismos Reproductivos De La Especie, Nibia Berois, Rafael O. De Sá

Biology Faculty Publications

El orden Gymnophiona comprende anfibios ápodos, ciegos, de hábitos cavícolas y acuáticos. Como consecuencia de estos hábitos resulta muy difícil su colecta, lo cual redunda en un escaso conocimiento de la biología del orden y sobre las relaciones filogenéticas del mismo.

Una de las características más particulares del grupo se refiere a la modalidad reproductora, ya que aproximadamente el 50% de las especies presentan viviparidad y la totalidad de ellas tienen fecundación interna. Es por esta razón que el estudio del aparato reproductor ha sido encarado por diversos autores, en especial por Wake (1968, J. Morphol. 126: 291) con una …

Description Of The Form Of Wing-Flashing Behavior In Northern Mockingbirds (Mimus Polyglottos), Lyn M. Harper, Kathryn J. Schneider

Honors Theses

The purpose of this study was to describe the form and location of wing-flashing behavior in mockingbirds and to identify differences in flashing between young and adult birds through film analysis techniques and observation. Subjects consisted of 50 mockingbirds from the University of Richmond campus. Analyses of the data suggested that there were three types of wing-flashes based on degree of wing extension. Flashes were most likely to occur in direct sunlight and in grass. No significant differences in the form of flashes between adult and juvenile mockingbirds were found. It is hoped that this study will provide insight into …

The Effect Of Bilateral Adrenalectomy On The Electrocardiogram Of Meriones Unguiculatus, Jeff A. Brown

Honors Theses

The effects of adrenalectomy on the heart rate and electrical potentials of the heart of the Mongolian gerbil were studied (using an EKG) in an attempt to determine in hyperkalemia is the cause of its short survival time following adrenal ablation.

The Distribution Of The Ctenophore, Mnemiopsis Leidyi (A. Agassiz), In A Vertical Thermal Gradient, James J. Leder Iii

Honors Theses

The distribution of organisms in an estuary is affected by a plethora of environmental factors. The ctenophore, Mnemiopsis leidyi, is found to exists over a wide range of these factors, temperature and salinity in particular, allowing it to occupy the estuary year round and make use of low salinity areas unavailable to most marine organisms.

Estructura Del Ovario De Chthonerpeton Indistinctum (Reinhardt Y Lutken, 1862) (Amphibia: Gymnophiona) Durante La Gestación, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

La morfología e histología del ovario para varias especies del orden Gymnophiona ha sido reportada por Wake (1968, J. Morphol. 126, 291) y para C. indistinctum por los autores (1984, XXIV Reunión de Comunicaciones, Soc. Zool. Uruguay).

Continuando con los estudios sobre el aparato genital de esta especie vivípara, se presenta ahora la estructura del ovario durante la gestación.

Se procesaron con fines histológicos, ovarios de dos hembras grávidas colectadas en las costas de los Dep. Montevideo y San José en abril, 1983. El número de ejemplares trabajados es muy reducido dado lo difícil que resulta su colecta …

Effects Of Adrenalectomy On Hemoconcentration And Blood Ph, Urea And Electrolytes In The Mongolian Gerbil (Meriones Unguiculatus), Magally Aellos De Cova

Master's Theses

The effects of adrenalectomy on some blood profiles of the Mongolian gerbil, Meriones unguiculatus, were studied in order to clarify the possible causes of its short survival after adrenal ablation. Measurements of hematocrit, pH, urea and electrolytes were made 18, 24 and 30 hours after surgery. Results show the expected alterations: hemoconcentration, metabolic acidosis, high values of urea and disturbances in electrolytes. While hyponatremia was significant only after 24 hours, important hypochloremia was not present at any time. Hyperkalemia was the most significant alteration observed. It occurred as early as 18 hours after surgery, suggesting that it may be an …

Characteristics Of A Ca++ Atpase Enzyme In The Epidermis Of Molting Blue Crabs, Callinectes Sapidus, Joanne Elizabeth Lapetina

Master's Theses

Epidermal Ca⁺⁺-activated ATPase was investigated in relation to the molt cycle of the blue crab, Callinectes sapidus. Premolt and postmolt tissue samples demonstrated significant elevations in Ca⁺⁺-activated ATPase activity in comparison to intermolt tissue samples. These results support the suggestion that this enzyme may participate in demineralization of the old cuticle, as well as calcification of the new cuticle.

The enzyme is localized in the heavy particulate-nuclear fraction and is distinguished from mitochondrial Ca⁺⁺ ATPase found in other tissues by differences in sensitivity to mersalyl acid. 0 The enzyme is most active at 49 C …

The Effects Of Photoperiod And Melatonin Injections On The Reproductive System Of The Male Mongolian Gerbil (Meriones Unguiculatus), Luis Jose Cova Marchan

Master's Theses

This work was undertaken to study the effects of photoperiod and melatonin on fertility in male Mongolian gerbils (Meriones unguiculatus). Four groups of fifteen animals each, were placed in different photoperiods (ambient, ranging from 14L:10D to 11.3L:12.3D; 24L:10D; 14L:10D; and 1L:23D). After 35 days, three gerbils from each photoperiod condition were sacrificed and the testes, epididymides, seminal vesicles, prostate, kidneys, adrenals, thymus and hypophysis were weighed. The testes and epididymides were placed in Bouin's fixative and used for histological studies. Also, two males from each photoperiod condition were paired individually with a female. The remaining animals of each photoperiod condition …

Wood Anatomy And Relationships Of Neowawraea (Euphorbiaceae), Dörthe S. Brandt, W. John Hayden

Honors Theses

Wood anatomy of three specimens of Neowawraea phyllanthoides Rock, a rare and endangered member of Euphorbiaceae endemic to the Hawaiian Islands, is described and compared with woods of other genera of subfamily Phyllanthoideae. Neowawraeahas often been associated or synonymized with Drypetes Vahl. Wood of Neowawraea is diffuse porous, perforation plates are simple, imperforate tracheary elements are thin-walled septate fiber-tracheids, rays are heterocellular and crystalliferous, and axial xylem parenchyma is restricted to a few scanty paratracheal and terminal cells. In several respects these results differ from earlier published descriptions of the wood of this taxon; these earlier descriptions are shown …

Leptodactylus Podicipinus (Cope, 1862) Y Leptodactylus Chaquensis Cei, 1959 (Anura, Leptodactylidae), En El Uruguay, Raúl Vaz-Ferreira, Rafael O. De Sá, Federico Achaval, Annelise Gebrau

Biology Faculty Publications

En base al estudio de las colecciones obtenidas principalmente en excursiones a la zona NO de Uruguay con motivo del relevamiento faunístico del área de Salto Grande, se avanzó considerablemente en el conocimiento de la distribución de Leptodactylus podicipinus (Cope, 1862) y Leptodactylus chaquensis (Cei, 1950), en nuestro país.

Se cita el material estudiado y las observaciones de campo realizadas; se dan los caracteres generales de ambas especies, se describen los hábitats, y se tratan las características de las vocalizaciones.

The Role Of Adrenomedullary Hormones In Survival Of The Adrenalectomized Mongolian Gerbil, Meriones Unguiculatus, Carol B. Ussery

Master's Theses

Thee effects of adrenalectomy and catecholamine replacement therapy on survival were studied in Meriones unguiculatus, the Mongolian gerbil. Adrenalectomized gerbils that received epinephrine lived significantly longer than the controls untreated adrenalectomized gerbils) and animals that received either norepinephrine or a combination of epinephrine and norepinephrine. Results also indicated that these epinephrine-treated animals lost more depot fat that either controls or other groups receiving treatment. In spite of the short survival benefit given by epinephrine, the mechanisms governing the critical adrenal dependency in this species remain unknown.

The Role Of The Adrenal Cortex In Fat Metabolism Of Meriones Unguiculatus, The Mongolian Gerbil, Saffia Baggia

Master's Theses

The effects of adrenalectomy and corticoid replacement therapies on survival, weight loss, depot fat and blood free fatty acid were studied in Meriones unguiculatus, the Mongolian gerbil. Adrenalectomized gerbils that received cortisol and aldosterone lived significantly longer and lost significantly more weight than the controls (adrenalectomized gerbils not receiving any treatment) and the sham-operated groups. Cortisol and aldosterone treatment were also effective in mobilizing significantly greater amounts of depot fat into free fatty acid. Cortisol and aldosterone treated groups had significantly less blood free fatty acid than the control and the sham-operated groups.

Observaciones Sobre La Biología De Phyllomedusa Iheringi Boulenger, 1885, (Anura, Hylidae), Rafael O. De Sá, Annelise Gerhau

Biology Faculty Publications

RESUMEN:

Se presentan las características que permiten diferenciar las larvas de Phyllomedusa iheringi de las de otros anuros que habitan en nuestro territorio, junto con algunas observaciones sobre la biología de esta especie poco conocida en el Uruguay.

SUMMARY:

The characteristics that differentiate the larvae of Phyllomedusa iheringi from other anurans that live in Uruguay are presented here. Some observations on the biology of this species are also recorded.

Reproductive Biology Of The Rat Lungworm Angiostrongylus Cantonensis (Metastrongyloidea: Angiostrongylidae), Grace Spatafora Harris

Master's Theses

Twenty rats (Rattus norvegicus) received infective inocula of 5, 10, 20, and 40 third-stage larvae of Angiostrongylus cantonensis. The effects of varying doses of larvae on prepatent period larval production, worm establishment, worm size, and fertility were studied. The aquatic gastropod Biomphalaria glabratta was the experimental intermediate host.

The duration of the prepatent period varied from 37 to 45 days. The shortest prepatent period was observed in animals that received the highest infective inoculum. The prepatent period showed a significant inverse relationship with increasing inoculum size. Larval production increased logarithmically, followed by a plateau phase. The number of larvae per …

An Electrophoretic Comparison Of Gene Loci In Etheostoma Nigrum And Etheostoma Olmstedi From The James River Drainage, Virginia, Randall Keith Falls

Master's Theses

As many as five different populations of Etheostoma nigrum and Etheostoma olmstedi have been identified in the James River drainage, Virginia. Genetic variation of these populations was analyzed with starch gel electrophoresis and revealed only three distinct populations. Nine loci encoding five enzyme systems and two loci encoding muscle proteins were examined in tissue homogenates. All populations were monomorphic with the exception of the esterase-3 (Est-3), phosphoglucomutase (Pgm-1) and phosphoglucose isomerase (Pgi) loci. Two alleles of Est-3 exhibited activity in the homozygous and heterozygous conditions. Pgm-1 occurred as two alleles with a high degree of heterozygosity (46% for E. nigrum …