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Reproduction And Morphology Of Two Annual Taxa Of Sporobolus (Poaceae)., Elvera W. Skokan

Student Work

Morphology and reproduction were studied in two annual taxa of Sporobolus (Poaceae) at eight locations in eastern Nebraska. Estimated percent cleistogamy was 93.2% in S. neglectus and 83.8% in S. vaginiflorus in specimens collected throughout the 1982 growing season. Anthers of cleistogamous florets were smaller in size and lower in number than anthers of chasmogamous florets. Pollen-ovule ratios were significantly lower in cleistogamous than in chasmogamous florets and cleistogamous florets showed precocious development. Agamospermous reproduction may also be present in the taxa. The lack of intermediate forms between the two taxa in the locations studied may be attributable to the …

Vegetational Changes Under Isolated Juniperus Virginiana In An Eastern Nebraska Bluestem Prairie., Janet L. Gehring

Student Work

Changes in species composition of a Bluestem prairie were evaluated under isolated, 10-22 year old Juniperus virginiana (Eastern Red Cedar) in eastern Nebraska. Percent canopy cover was measured in full-canopy, canopy-edge, and open-canopy plots which were located along transects oriented to the cardinal compass directions. A total of 53 species were recorded. Andropogon scoparius and A. gerardii dominated open-canopy and canopy-edge plots; Poa pratensis and A. scoparius dominated full-canopy plots. Canopy cover of most prairie species decreased under full canopy but Poa pratensis and Carex spp. increased. There was a positive correlation between tree size and both the decrease of …

Employee Selection Base On Susceptibility To Occupational Illness, Mark A. Rothstein

Michigan Law Review

This Article attempts to compile the latest information available concerning this difficult problem. Part I reviews the scientific literature, explaining the biological basis of increased risk of occupational disease. Part II explores the efforts of various employers to incorporate this research into their personnel practices. Part III surveys the legal response to these practices. Employees may challenge medical screening on a variety of theories, most of which were not designed to deal with the problem of susceptibility to occupational disease. Not surprisingly, none of the approaches offers an entirely satisfactory response to the problem. This Article offers no clear answers. …

Report, University Of South Florida Botanical Garden 1983 Administrative Report, Frederick B. Essig

USF University Archives and Documents

Administrative report of the Botanical Gardens for 1983, issued by Director Frederick B. Essig. Topics include goals, botanical collection, staffing needs, programming, finances, and expansion.

Annual Report, 1982 Annual Report Of The University Of South Florida Herbarium, January 24, 1982, Richard P. Wunderlin

USF University Archives and Documents

Annual Report of the University of South Florida Herbarium for the year 1982. Topics include highlights, specimen acquisitions, collection overview, research projects, publications, exchange relationships, field work, campus services, facilities, funding, and library holdings.

Effects Of A Climatic Gradient On Columbian Ground Squirrel (Spermophilus Columbianus) Life History, Richard Michael Zammuto

Digitized Theses

No abstract provided.

Food Resource Utilization By Five Species Of Benthic Feeding Fish In Passamaquoddy Bay, New Brunswick, John Stevenson Macdonald

Digitized Theses

Feeding relationships of various fish species, and their relationship to the composition of the surrounding sediments, were observed for one year at two sites in the lower Bay of Fundy region. The fishes were the ocean pout (Macrozoarces americanus), winter flounder (Pseudopleuronectes americanus), plaice (Hippoglossoides platessoides), cod (Gadus morhua) and witch flounder (Glyptocephalus cynoglossus). After reducing the size of the data matrix by removing redundant variables (prey items), interspecific diet overlap and the degree to which stomach contents reflect benthic composition were assessed using discriminant functions analysis. Variables were ranked by their power to discriminate among pairwise comparisons of groups: …

Spatial Processes In The Analysis Of Vegetation, Janos Podani

Digitized Theses

Vegetation Science often relies on methods whose principal strategy involves the change of some parameters of sampling. There is, in fact, a time-static spatial dynamism in the analysis of vegetation, and most changes can be ordered into a sequence, whereby spatial processes are defined. The objective of the present thesis is to create a theoretical framework for the discussion and review of time-static spatial processes, to give a methodological basis for their analysis, and to illustrate some possibilities through real and simulated examples.;Two basic types of processes are distinguished: (1) the primary processes defined by the investigator, and (2) the …

Electrophysiological Investigation Of Amygdaloid Inputs To The Ventral Pallidum Via The Nucleus Accumbens And Their Modulation By Dopamine, Conrad Chi Yim

Digitized Theses

The nucleus accumbens (NA) receives inputs from limbic structures and projects to the basal ganglia. In addition, it is the target of a heavy dopaminergic projection from the ventral tegmental area (VTA). The purpose of the present study is to investigate using electrophysiological techniques whether or not the NA forms a functional link between the amygdala (AMY) and the ventral pallidum (VP), and whether or not the mesolimbic dopamine projection from the VTA interacts with this pathway.;Electrical stimulation of the basolateral nucleus of the AMY caused an excitation was attenuated by ionotophoretically applied dopamine (DA) or electrical stimulation of the …

An Analysis Of The Dna Repair-Recombination Functions And The Uvsx-Uvsy Dna Repair Pathway Of Bacteriophage T4, Leonard Paul Wakem

Digitized Theses

Due to the complexity of the T4 uvsX-uvsY DNA repair pathway, we have attempted to define the functions and repair mechanisms involved in the pathway, using several different techniques. The DNA repair-recombination functions of the pathway were analyzed biochemically and genetically to aid in understanding the role of these functions in the cell.;To study the functions of the uvsX and uvsY gene products, DNA intermediates formed after uv-irradiation were extracted from uvsX and uvsY mutant-infected cells and analyzed by sucrose gradient centrifugation. Results of this analysis suggested that the uvsX and uvsY gene products function in a DNA "joining" reaction.;The …

Studies On The Structure And Origin Of The Parasporal Inclusion Of Sporulating Bacilli, James Peter Insell

Digitized Theses

The parasporal inclusions of B. thuringiensis subspecies kurstaki, subspecies israelensis, subspecies schwetzova, subspecies alesti, subspecies finitinus, and B. cereus subspecies medusa and subspecies lewinia were purified and analyzed by one-dimensional slab gel electrophoresis. The inclusion of each of the above subspecies was composed of different polypeptides. The protein composition of the inclusions was correlated with the sahpe, structure and toxicity of the inclusion. Four types of inclusions were formed by the seven subspecies studied. Three representative subspecies were chosen for further study.;Two strains of B. cereus and eight subspecies of B. thuringiensis were screened for the presence of plasmid DNA. …

Population Attributable Risk: Definition, Estimation And Application, Yang Mao

Digitized Theses

The purpose of this thesis is to expand the applicability of population attributable risk, by reorganizing established theory and developing relevant techniques.;The general definition of population attributable risk is adapted and extended to five areas of application. The suitability of its calculation formulae is discussed with respect to various study designs and the available external data. The interval estimations of these calculation formulae are completely developed and organized for easy applicability. Their confidence intervals are also compared with regard to asymptotic efficiency and distribution assumptions. The effect of errors of measurement on these calculation formulae is measured and collated in …

Hypothalamic And Peripheral Noradrenergic Responses To Changes In Baroreceptor Input In Conscious Rats With And Without Renal Nerves, Kaushik Parbhubhai Patel

Digitized Theses

Hypothalamic and peripheral noradrenergic systems have been implicated in baroreflex control of arteria pressure. However, the relationship between changes in the hypothalamic noradrenergic activity and changes in peripheral sympathetic activity is unclear. The first study examined this relationship in conscious Wistar rats following changes in baroreceptor input to the CNS produced by: (1) transection of aortic depressor nerve (ADN) (removal of specific baroreceptor input), (2) acute hypotension for 60 min produced by infusion of nitroprusside, and (3) acute hypertension for 60 min produced by infusion of phenylephrine. An index of norepinephrine (NE) turnover was used to assess the noradrenergic activity …

The Relation Between Food Abundance And Reproductive Performance Of Tree Swallows, Terry Edwin Quinney

Digitized Theses

Few field studies have examined experimentally the importance of food availability on adult activity and breeding performance in birds. I studied two populations of insectivorous Tree Swallows Tachycineta bicolor, 3 km apart, that differed primarily in the amount of food available to the breeding birds. I obtained an index of food abundance and conducted experiments involving the transfer of clutches and broods between populations. Tree Swallows showed substantial phenotypic plasticity in breeding characteristics and parental activities. My results demonstrated that food abundance during the the breeding season influenced clutch size, egg quality, nestling growth, behavior, survival to fledging and adult …

Superovulation And Infertility In Immature Rats, Elizabeth Anne Walton

Digitized Theses

This study examined the possible causes of infertility in immature rats following superovulation (SOV) with pregnant mares' serum gonadotrophin (PMSG). The areas looked at included the timing of ovulation, oocyte normality, fertilization, oviductal transport, early embryo development and implantation.;SOV with a single injection of PMSG or continuous infusion of follicle-stimulating hormone (FSH) was compared and in some rats the period of action of PMSG was restricted to (TURN) 58 h by use of a specific antiserum (a/s). Pregnancy was observed in most FSH-infused rats whereas following SOV with PMSG pregnancy failed prior to day 5. Increased ovarian oestradiol secretion was …

Cationic Ferritin Labeling Of Anionic Sites At Cellular Surfaces, Timothy Victor Brac

Digitized Theses

Cationic and anionic ferritins were used to map the distribution of charged sites on intracellular and extracellular surfaces. The distribution of tracers at cell surfaces and injected into live cells was examined by electron microscopy.;The distribution of microinjected ferritin showed that intracellular surfaces are negatively charged. Highly cationic ferritins (HCF pI > 9) were mostly bound to and caused swelling of the rough endoplasmic reticulum. Cationic ferritin (CF pI 7.0-8.0) and anionic ferritin (AF pI 4.0-4.4) caused no changes in morphology. Ferritin distribution in the cytoplasmic space varied with its charge. Significantly more CF was bound to surfaces than was found …

Theoretical Properties Of Multinomial Logistic Regression, Shelley Brenda Bull

Digitized Theses

A large sample relative efficiency of estimation for multinomial logistic regression compared to multiple group discriminant analysis has been derived and evaluated for parameter values relevant to epidemiological research. The large sample distributions of the two procedures are based on the assumptions of multivariate normality and common covariance structure among groups. Matrix calculus methods were found to be valuable in obtaining concise expressions for the large sample variances.;Relative efficiency does not decrease as the number of response categories increases, although increases tend to be small. The number of explanatory variables and the magnitude of the odds ratios associated with them …

Androgen Regulation Of Fsh-Induced Aromatase Activity In Cultured Rat Granulosa Cells, Susan Anne Daniel

Digitized Theses

This study examines the role of androgen in the regulation of FSH-induced aromatase activity in rat granulosa cells in vitro. Experiments were designed to determine whether androgens act solely as substrates for FSH-induced aromatase activity or whether they also participate in the mechanism by which FSH increases the activity of the enzyme.;Granulosa cells were isolated from ovaries of immature rats and cultured during a 36- to 60-h "induction period" in the presence or absence of FSH with or without steroids and/or other compounds. Cells were then incubated for a further 6- and 12-h "test period" with aromatizable substrate (testosterone). Accumulation …

Crataegus Crus-Galli L Sensu Lato In Southern Ontario: Phenotypic Variation And Variability In Relation To Reproductive Behavior, Timothy Adam Dickinson

Digitized Theses

Crataegus crus-galli L. sensu lato is one of the most widespread groups of hawthorn taxa in eastern North America. Early twentieth century classifications of this group have recognized a considerable degree of dissection into rather narrowly defined species. However, the status of many of these species has been unclear in view of the widespread belief that apomixis is frequent throughout the entire genus. Crataegus crus-galli s. l, was examined at 11 sites across southern Ontario in order to characterize the pattern of morphological variation present in one part of its range. Cluster analyses that employed a selection of resemblance functions …

A Comparison Of The Membranes Of Bacillus Megaterium Spores And Cells, Mary Lynn Elmes

Digitized Theses

The biochemical and biophysical properties of Bacillus megaterium KM spore and cell membranes were investigated. Spore inner and outer membranes have been prepared from coat-stripped spores and solubilized spore coat proteins, respectively.;The spore inner and cell membrane phospholipids are similar, except for a decrease in phosphatidylethanolamine in late vegetative state or early sporulation and a decrease in phospholipid content to one-half that of the cell membrane early in spore formation (Stage III). The unique red carotenoid of the inner membrane appears later in B. megaterium KM (Stage V) than in B. megaterium QM B1551 (Stage III-IV). The spore inner and …

Modulation Of The Immunoglobulin-E Response By Dnp-Coupled Bordetella Pertussis, Naeem Akhtar Essani

Digitized Theses

BP vaccine is one of the adjuvants of choice for potentiating the IgE antibody response in rodents. In the present investigations administration of hapten (dinitrophenyl)-coupled Bordetella pertussis organisms (DNP-BP) failed to induce significant levels of anti-DNP IgE antibodies in CBA mice, regardless of the presence of an additional adjuvant {lcub}Al(OH)(,3){rcub}, while high levels of IgG antibodies were produced. The administration of DNP-BP to a number of inbred mouse strains, differing in H-2 genotype showed a clear segregation into low and high IgE responder Phenotypes. The low IgE responder status of CBA mice for DNP-BP, however, was not changed by conventional …

Surface Membrane Biology Of Schistosoma Mansoni, Shona Spensley Mcdiarmid

Digitized Theses

The apical and basal membranes of the surface syncytium of Schistosoma mansoni were separated and found to exhibit the predictable, polarised ATPase distributions of other transporting epithelial layers. A multilamellar body fraction was prepared from adult worms and the major phospholipid classes determined. Phosphatidylcholine constituted the major phospholipid class. An apparent projection core was described in schistosome multilamellar bodies, which showed structural analogy to multilamellar bodies from lung.;Methods were devised for sequentially stripping the outer (OB) and inner (IB) bilayers from the surface apical membrane complex of adult worm pairs. Tritiated Concanavalin A and {lcub}('125)I{rcub} diazotised iodosulfanilic acid were found …

The Effect Of Stringent Control On The Production Of Enterotoxin, Tryptophanase, And Beta-Galactosidase By Escherichia Coli In A Recycling Fermentor, Robin Leigh Eifert

Doctoral Dissertations

The recycling fermentor has been shown to be a good tool for studying microorganisms at very slow growth rates. Previous studies have determined that there are three distinct phases of growth based on biomass. Phase 3 has been shown to be initiated by the induction of the stringent response and to be regulated by the levels of guanosine 5'-diphosphate 3'-diphosphate (ppGpp) within the cell. By comparing the growth patterns of three enterotoxigenic Escherichia coli strains to that of E. coli strains of known rel genotypes, the Rel phenotypes of the enterotoxigenic strains were determined.

Both enterotoxin production and secretion in …

Novel Aspects Of Ultrastructure In Two Species Of Cyanobacteria (Agmenellum Quadruplicatum, Mastigocladus Laminosus), Sandra Anne Nierzwicki-Bauer

Doctoral Dissertations

Novel aspects of morphology and ultrastructure were examined in two species of cyanobacteria. A complete, three-dimensional, ultrastructural reconstruction of the unicellular cyanobacterium Agmenellum quadruplicatum was carried out by means of high-voltage electron microscopy of thick sections and computer-aided reconstruction of serial thin sections. The photosynthetic thylakoid system consisted of 3-6 membrane sheets that traversed and were parallel to the long axis of the cell. These sheets were arranged as an anastomosing network of concentric shells. They coalesced and approached the cytoplasmic membrane at three peripheral loci along the entire length of the cell. The central cytoplasm of the cell was …

Development Of A Culture System For Bovine Luteal Cells: Examination Of Luteotropic And Luteolytic Mechanisms, Joy Lee Pate

Doctoral Dissertations

The function of bovine luteal cells in tissue culture was examined. Corpora lutea from regularly cycling dairy cows were dissociated with collagenase and cultured in Ham's F-12 medium with or without serum. The serum-free medium was supplemented with insulin, transferrin and hydrocortisone. Addition of LH to the serum-containing medium did not increase P(,4) production. When the luteal cells were cultured in serum-free medium, LH produced an increase in P(,4) during the first 24 hours of culture. The responsiveness of the cells to LH then declined, and remained low until approximately day 7 of culture, at which time the cells regained …

Comparative Biochemical And Genetic Studies Of Testa Development In Normal And Hull-Less Phenotypes Of Pumpkin (Cucurbita Pepo L), Susan Gerardette Stuart

Doctoral Dissertations

A detailed investigation was conducted to examine further the biochemical and genetic bases of the hull-less phenotypic condition in testae of seeds of pumpkin (Cucurbita pepo L.). During seed development, testa moisture declined substantially (30%) in both phenotypes, whereas testa dry and fresh weights increased dramatically between 10 to 20 days post-anthesis and then declined steadily until seeds reached maturity. Structural compositional analysis revealed marked reductions in lignin (78%) and cellulose (50%) in hull-less compared with normal phenotypes; whereas no differences in non-cellulosic polysaccharides were found at 20 days post-anthesis. Between 20 days post-anthesis and maturity, pectin content of testae …

Electrophoretic And Enzymatic Identification Of Proteins Associated With The Development Of Competence In Bacillus Subtilis, Susan Alicia Coughlin

Doctoral Dissertations

A two-dimensional zymogram procedure for the analysis of nucleases is described. Using purified deoxyribonuclease I (bovine pancreas), as little as 10 pg of nuclease can be detected. Isoelectric focusing (IEF) and non-equilibrium pH gradient electrophoresis (NEPHGE) were compared as first dimensions, in combination with SDS electrophoresis as the second dimension, in analyzing nucleases in lysates of Bacillus subtilis. All renaturable nuclease activities detected following SDS electrophoresis alone were resolved in NEPHGE-SDS electrophoresis gels whereas, in IEF-SDS gels, most were either at the basic end or were not present in the second dimensional gel. This method of analysis has revealed a …

Ecology Of Gracilaria Tikvahiae Mclachlan (Gigartinales, Rhodophyta) In The Great Bay Estuary, New Hampshire, Clayton Arthur Penniman

Doctoral Dissertations

The reproductive phenology, growth and variation of chemical composition of Gracilaria tikvahiae from the Great Bay Estuary, N.H. were evaluated. A major objective was an analysis of the chemical composition, particularly agar content and properties, of plants separated into reproductive categories. The net photosynthetic responses of G. tikvahiae to several irradiance, temperature and salinity regimes were determined.

Gracilaria tikvahiae plants from the Great Bay Estuary were vegetative throughout most of the year. However, discrete maxima of tetrasporic and spermatangial plants occurred during June-July and for cystocarpic plants during July-August. The in situ growth of Gracilaria tikvahiae was highest during June-September, …

An Electrophoretic Analysis Of The Genetic Variation In The Wild And Cultivated Soybean Germplasm, Mark Bessom Gorman

Doctoral Dissertations

Over 400 soybean (Glycine max (L.) Merr.) cultivars and plant introductions and more than 100 wild soybean (Glycine soja Sieb & Zucc.) plant introductions from a wide geographic distribution were examined by polyacrylamide, slab electrophoresis for genetic variation in 15 enzymes. Allozymes for 25 loci were found. All but three of these loci were confirmed by experimental crosses. Approximately 20 non-variable loci were also hypothesized. Models presented explaining the genetic control for each of the observed enzyme zymograms, were based on inheritance studies, on patterns of distribution of isozymes in various tissues or developmental stages, zymograms in related species, information …

Population Ecology And Production Of The Sandy-Beach Amphipod Haustorius Canadensis (Crustacea: Haustoriidae) (Maine, New England), Theodore Edward Donn

Doctoral Dissertations

While much is known concerning the structure of the amphipod-dominated marine sandy-beach communities along the Atlantic coast of the United States, little is known about the functional relationships within them. The goal of this study was to determine the seasonal trophic dynamics and life history of the sandy-beach amphipod Haustorius canadensis in order to gain a better understanding of the functioning of northern New England sandy-beach communities. Haustorius canadensis is one of the three dominant amphipods on these beaches and remains strictly intertidal throughout the year making it an ideal organism for this study. The site chosen for this study …