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Nitrogen Fluxes In Mangrove Sediments And Their Coupling With Aquatic Primary Productivity In Terminos Lagoon, Campeche, Mexico., Victor Hugo Rivera-Monroy Jan 1995

Nitrogen Fluxes In Mangrove Sediments And Their Coupling With Aquatic Primary Productivity In Terminos Lagoon, Campeche, Mexico., Victor Hugo Rivera-Monroy

LSU Historical Dissertations and Theses

The significance of nitrogen transformations in mangrove sediments to the exchange of nitrogen in mangrove forests and influence on aquatic primary productivity was studied between 1990-1992 in Terminos Lagoon, Mexico. Fluxes of dissolved inorganic and organic nitrogen, particulate nitrogen (PN), and total suspended sediments (TSS) were measured in a fringe mangrove forest using the flume technique. There was a net import of NH$\sb{4}\sp{+}$ and NO$\sb{2}\sp{-}$ + NO$\sb{3}\sp{-}$ from the creek and basin forest, while particulate (PN) and dissolved organic nitrogen were exported to the creek and basin forest. There was a net import of TSS to the fringe forest from …

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Bamboo Specialization In Amazonian Birds., Andrew Ward Kratter Jan 1995

Bamboo Specialization In Amazonian Birds., Andrew Ward Kratter

LSU Historical Dissertations and Theses

By spot-mapping territories of lowland forest birds in southeastern Peru, 19 "bamboo specialists" were documented to be restricted to thickets of bamboo (Guadua weberbaueri). Six specialists are restricted to thickets throughout their entire geographic range (obligate bamboo users); seven specialists may use other habitats sparingly away from southeastern Peru (near-obligate bamboo users); the remaining six species are frequent users of habitats lacking bamboo in area besides southeastern Peru (facultative bamboo users). The 19 specialists, all insectivorous, were classified into five guilds based on foraging maneuver and substrate preferences: four sallying tyrannid species; four arboreal antbirds; four stem-searching specialists; four dead-leaf-searching …

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Daily Variations In Protein Synthesis And Tissue Responsiveness To Growth Hormone, Prolactin And Insulin-Like Growth Factor-I In The Gulf Killifish, Fundulus Grandis Baird And Girard., Zeleke Negatu Jan 1995

Daily Variations In Protein Synthesis And Tissue Responsiveness To Growth Hormone, Prolactin And Insulin-Like Growth Factor-I In The Gulf Killifish, Fundulus Grandis Baird And Girard., Zeleke Negatu

LSU Historical Dissertations and Theses

Circadian variations of $\sp{14}$C-glycine incorporation into protein and the responsiveness of muscle tissue to growth hormone, prolactin and insulin-like growth factor-I were examined in gulf killifish, Fundulus grandis. Incorporation of label during a 5 h period following $\sp{14}$C-glycine injection was tested at different times of day (LD 12:12). Incorporation varied during the day in all the tissues examined (scale, muscle, liver and intestine). The times of peak incorporations differed among the tissues. Scales showed peak incorporation during the dark hours. Peak incorporation by muscle occurred at the onset of light. These patterns were similar in male and female fish. The …

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The Habitat, Ecology And Epidemiology Of Eastern Equine Encephalomyelitis In Southeast Louisiana., Kenny L. Samui Jan 1995

The Habitat, Ecology And Epidemiology Of Eastern Equine Encephalomyelitis In Southeast Louisiana., Kenny L. Samui

LSU Historical Dissertations and Theses

Many unanswered questions on the epidemiology and ecology of eastern equine encephalomyelitis (EEE) still preclude a complete understanding of its natural history. Among these are the distribution and epidemic vectors of EEE virus (EEEV) in different regions, habitats, and foci; its inter-epidemic maintenance, and overwintering mechanisms. Phase 1 of a research project designed to find answers to the above questions with regard to southeast Louisiana was conducted over 1992 and 1993, and consisted of several individual studies. These included 3 mosquito studies to determine major horse- and bird-feeding mosquito species that could be the EEEV epidemic vectors in southeast Louisiana; …

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Cloning, Expression, Primary Structure, And Insertion Mutagenesis Of The Pyruvate Formate-Lyase Enzyme Of Aeromonas Hydrophila., Mohamed Alaa Eldin Abdelalim Awad Jan 1995

Cloning, Expression, Primary Structure, And Insertion Mutagenesis Of The Pyruvate Formate-Lyase Enzyme Of Aeromonas Hydrophila., Mohamed Alaa Eldin Abdelalim Awad

LSU Historical Dissertations and Theses

The pyruvate formate-lyase enzyme (Pfl), a key enzyme in alcoholic fermentation, catalyzes the anaerobic conversion of pyruvate into acetyl-CoA and formate in prokaryotes. The pyruvate formate-lyase gene (pfl) of the facultative anaerobe Aeromonas hydrophila was cloned and sequenced. Subsequently, the Pfl was characterized based on the deduced amino acid sequence and evaluated in vivo following insertion mutagenesis. Finally, the pathogenesis of a defined mutant was compared to wild type A. hydrophila in channel catfish. The pfl of A. hydrophila was identified from two recombinant pBluescript SK(-) clones excised from a $\lambda$ ZAP II phage library. Both clones carried the same …

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Molecular Cloning, Sequencing, And Regulation Of The Rhodobacter Capsulatushemb Gene., Karl Joseph Indest Jan 1995

Molecular Cloning, Sequencing, And Regulation Of The Rhodobacter Capsulatushemb Gene., Karl Joseph Indest

LSU Historical Dissertations and Theses

The common tetrapyrrole pathway in the photosynthetic bacterium, Rhodobacter capsulatus, is responsible for the synthesis of bacteriochlorophyll, heme, vitamin B-12, and siroheme. The common portion of this pathway is regulated up to 100-fold by changes in oxygen tension. This regulation is accomplished by controlling the intracellular level of porphobilinogen. One way in which porphobilinogen levels could be controlled is by regulating the synthesis of porphobilinogen. Porphobilinogen synthase, encoded by the hemB gene, is the second enzyme in the common tetrapyrrole pathway that catalyzes the dimerization of 5-aminolevulinic acid to form the monopyrrole porphobilinogen. In order to further investigate the mechanism …

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Sediment Retention In A Bottomland Hardwood Wetland In Eastern Arkansas., Barbara A. Kleiss Jan 1995

Sediment Retention In A Bottomland Hardwood Wetland In Eastern Arkansas., Barbara A. Kleiss

LSU Historical Dissertations and Theses

One of the often-stated functions of wetlands is their ability to remove sediments and other particulates from water, thus improving water quality in the adjacent aquatic system. However, actual rates of suspended sediment removal have rarely been measured in freshwater wetland systems. To address this issue, suspended sediment dynamics were measured in a 85-km$\sp2$ bottomland hardwood (BLH) wetland adjacent to the highly turbid Cache River in eastern Arkansas during the 1988-90 water years. A suspended sediment mass balance was calculated using depth-integrated, flow-weighted daily measurements at wetland inflow and outflow points. Over the three year period, suspended sediment load decreased …

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Transcriptional Studies Of The Muscle-Specific Expression Of The Rabbit Muscle Phosphofructokinase Gene., Haiqing Fu Schiltz Jan 1995

Transcriptional Studies Of The Muscle-Specific Expression Of The Rabbit Muscle Phosphofructokinase Gene., Haiqing Fu Schiltz

LSU Historical Dissertations and Theses

The rabbit muscle phosphofructokinase (RM-PFK) gene is predominantly expressed in skeletal muscle. Its muscle-specific transcription was investigated using transient transfection studies, electrophoretic mobility shift assays, and DNaseI footprinting experiments. The evidence presented here provides the first example of the myogenic basic-Helix-Loop-Helix proteins regulating a gene that encodes a glycolytic enzyme. The 3 kb 5$\sp\prime$-flanking sequence of this gene directed the expression of the chloramphenicol acetyltransferase gene in muscle and non-muscle cells. MyoD, Myf5, and myogenin exhibited differential transactivation capabilities. MyoD had the most pronounced transactivational effect, and its N-terminal transactivation domain and the basic DNA-binding region were required for its …

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The Rabbit Muscle Phosphofructokinase Gene: Six Types Ofmrnas Are Tissue-Specifically Expressed By Multiple Promoters And Alternative Splicing., Shouhua Xiao Jan 1995

The Rabbit Muscle Phosphofructokinase Gene: Six Types Ofmrnas Are Tissue-Specifically Expressed By Multiple Promoters And Alternative Splicing., Shouhua Xiao

LSU Historical Dissertations and Theses

Phosphofructokinase (ATP:Fructose-6-phosphate 1-phospho-transferase, EC 2.7.1.11, PFK) catalyzes the phosphorylation of fructose 6-phosphate to generate fructose 1,6-bisphosphate, the rate-limiting step of glycolytic pathway. Li et al. (1990) have identified two cDNAs for the rabbit muscle PFK with an identical coding regions but different 5$\sp\prime$ untranslated regions (UTRs). In this dissertation research, six cDNAs for the rabbit muscle PFK mRNAs were cloned. These cDNAs are different in their 5$\sp\prime$ UTRs but have an identical open reading frame. The transcription initiation sites of two downstream promoters of this gene have been determined. A proximal promoter (Pa) is TATA-less and 86 bp upstream of …

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Behavioral And Chemical Ecology Of Formosan Subterranean Termites, Coptotermes Formosanus Shiraki., Jian Chen Jan 1995

Behavioral And Chemical Ecology Of Formosan Subterranean Termites, Coptotermes Formosanus Shiraki., Jian Chen

LSU Historical Dissertations and Theses

Three colonies of Formosan subterranean termites collected from Lake Charles, Louisiana were not antagonistic towards each other, and three of five colonies collected from New Orleans, Louisiana also showed no aggression. Colonies collected from widely separated parishes, however, often showed antagonistic behavior towards each other. Workers provided food to soldiers from different but amicable colonies whether nestmate soldiers were present or not. Intercolonial mutual grooming also was observed. Furthermore, termites assisted other termites of the same colony or an amicable one in finding food. This assistance in finding food occurred when termites foraged underground or on the surface. Based on …

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A Study Of Differences In Binding Of Hepatic Nuclear Proteins To The Upstream Region Of Glucocorticoid Regulated Tyrosine Aminotransferase Gene In Lean And Obese Rats., Huijun Dong Jan 1995

A Study Of Differences In Binding Of Hepatic Nuclear Proteins To The Upstream Region Of Glucocorticoid Regulated Tyrosine Aminotransferase Gene In Lean And Obese Rats., Huijun Dong

LSU Historical Dissertations and Theses

Glucocorticoids are required for the development of all forms of experimental obesity. Studies on Zucker fa/fa rats have revealed that the obese Zucker rat is hyper-responsive to the effects of glucocorticoids. This excessive response may result from an alteration in level or activity of a transcription factor in nuclei of obese fa/fa rat. Evidence from gel retardation assays using DNA fragments from the upstream region of glucocorticoid regulated tyrosine aminotransferase (TAT) gene and the nuclear extracts from obese and lean rats showed in this study that an increased amount of DNA fragment was shifted by nuclear extracts from obese rats …

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Effects Of Exogenous Female Sex Hormones On Food Intake, Macronutrients And Body Weight In The Ovariectomized Postbreeder Female Rat., Jan Barton Hamilton Jan 1995

Effects Of Exogenous Female Sex Hormones On Food Intake, Macronutrients And Body Weight In The Ovariectomized Postbreeder Female Rat., Jan Barton Hamilton

LSU Historical Dissertations and Theses

Hormone replacement therapy (HRT) is chosen by a growing segment of the postmenopausal population. Mid-life body weight gain is perceived to increase further with exogenous HRT. To examine hormonal effects on caloric intake (CI), carbohydrate (CHO), FAT, protein (PRO), chocolate and body weight (BW) in a female model, Sprague-Dawley postbreeder (n = 55) rats (10 mos., 10 litters of pups) were ovariectomized (OV) and implanted with 17 $\beta$ estradiol (E) and/or progesterone (P), or placebo in three separate studies (phases) of 10 days each. Uterine weights (p =.0001) and radioimmunoassay confirmed hormonal bioactivity. The sham (S) group with placebo implant …

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Biotic And Abiotic Factors That Affect The Development And Survival Of Cat Flea (Ctenocephalides Felis (Bouche)) Life Stages., William Joseph Lawrence Jr Jan 1995

Biotic And Abiotic Factors That Affect The Development And Survival Of Cat Flea (Ctenocephalides Felis (Bouche)) Life Stages., William Joseph Lawrence Jr

LSU Historical Dissertations and Theses

Biotic and abiotic factors that affect the development and survival of cat flea (Ctenocephalides felis (Bouche)) life stages were studied. Adult feas maintained on an artificial host system exhibited high rates of mortality when provided with dog hair substrates washed in either hexane or soap and water. Delayed egg production for fleas provided with bovine blood containing Na Citrate concentrations $>$8 mM was observed. Fleas fed with Na Citrate concentrations $\ge$24 mM had an increase in blood consumption and mortality. Certain concentrations of testosterone fed to fleas either in steer blood or in an alternate blood meal were associated …

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Follicular Development Patterns Of Pregnant Mares During The First Half Of Gestation., Marius Meintjes Jan 1995

Follicular Development Patterns Of Pregnant Mares During The First Half Of Gestation., Marius Meintjes

LSU Historical Dissertations and Theses

Information gained by studying follicular wave and endocrinological patterns of pregnant mares, may be useful in understanding reproductive wastage, infertility, control of the estrous cycle and physiological function of equine chorionic gonadotropin (eCG). Furthermore, supplementary follicular development, characteristic of the early equine pregnancy, may be used to harvest oocytes for gamete intrafallopian tube transfer and in vitro fertilization (IVF) procedures. The objectives of this study were to: characterize follicular wave patterns during the first half of the equine pregnancy; relate follicular development patterns to serum levels of estradiol-17$\beta$, progesterone, FSH and eCG; evaluate the effect of fetal genotype on follicular …

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Interleukin-2 Promoter/Enhancer Controlled Expression Of A Synthetic Cecropin-Class Lytic Peptide In Transgenic Mice., William Andrew Reed Jan 1995

Interleukin-2 Promoter/Enhancer Controlled Expression Of A Synthetic Cecropin-Class Lytic Peptide In Transgenic Mice., William Andrew Reed

LSU Historical Dissertations and Theses

Pathogens continue to evolve mechanisms of avoiding efforts to control their spread. Treatment with exogenous antimicrobials often occurs after the pathogen has reproduced extensively in the host. In the case of mammals, the immune system may not be fully mobilized for 72 h after the detection of foreign antigen. However, within 24 h of presentation of antigen by antigen-presenting cells to resting thymus-derived lymphocytes IL2 is produced. A class of broad spectrum antimicrobial peptides which constitute a major component of the insect immune system has been described and characterized. Called "cecropins", they are relatively non-toxic to normal cells from multicellular …

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Binding Of Hepatic Nuclear Proteins From Obese And Lean Zucker Rats To The Upstream Region Of Malic Enzyme Gene., Yibing Wang Jan 1995

Binding Of Hepatic Nuclear Proteins From Obese And Lean Zucker Rats To The Upstream Region Of Malic Enzyme Gene., Yibing Wang

LSU Historical Dissertations and Theses

Adrenal glucocorticoids are essential for the development of all forms of experimental obesity. In the obese (fa/fa) Zucker rats, adrenalectomy prevents the further development of obesity, and glucocorticoid replacement restores the obese phenotype. We have hypothesized that this dependence on glucocorticoids is due to differences in transcriptional regulation of a group of genes that are normally regulated by glucocorticoids. We have chosen to study the DNA fragments from the upstream region of the malic enzyme (ME) gene, which is positively regulated by glucocorticoids. Hepatic nuclear extracts from lean and obese Zucker rats were used in band shift studies to look …

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In Vitro Maturation, In Vitro Fertilization And Development Of Bovine Oocytes., Li Zhang Jan 1995

In Vitro Maturation, In Vitro Fertilization And Development Of Bovine Oocytes., Li Zhang

LSU Historical Dissertations and Theses

To improve the efficiency of the culture system for bovine in vitro fertilization (IVF), several factors affecting the success of in vitro maturation (IVM), IVF and in vitro culture (IVC) of bovine oocytes were studied. A simple and efficient procedure has been developed for IVM/IVF/IVC of bovine follicular oocytes, which consistently produced 45 to 50% morulae and blastocysts during the treatment of over 6,000 oocytes. Ovary holding temperatures of $\rm 0\sp\circ C,\ 18\sp\circ C\ and\ 25\sp\circ C$ were found to affect the rate of maturation, fertilization and cleavage (P $<$ 0.05). When ovaries were held at 25$\sp\circ$C for 3 h, 20% of the oocytes developed to blastocysts and hatched in vitro, indicating that this temperature is suitable for holding ovaries during transportation. The highest cleavage rate (79%) was obtained when oocytes were matured and fertilized both at 39$\sp\circ$C in 5% CO$\sb2$. Fertilization rate was impaired with a lowered incubation temperature (37$\sp\circ$C) and CO$\sb2$ level (2.5%). Cumulus cells were shown to be important and necessary for IVM and acquisition of competence for full embryonic development. Cumulus cell removal before IVM, before IVF or 7 h after IVF reduced the rates of maturation, fertilization and development at all embryo stages evaluated (P $<$.05). Cumulus cell removal at 20 h after fertilization resulted in a rate of development similar to control embryos (P $>$.05). Co-culture enhanced the development of IVF-derived embryos. More embryos …

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Modelling A Multispecies Schooling Fishery In An Upwelling Environment, Mauritania, West Africa., Sidina Ould Dedah Jan 1995

Modelling A Multispecies Schooling Fishery In An Upwelling Environment, Mauritania, West Africa., Sidina Ould Dedah

LSU Historical Dissertations and Theses

Off Mauritania, Northwest Africa, small pelagic fish have long been a valuable target of a large and diverse international fleet. In the early 1990's, average annual catch was about 400,000 metric tons in which three to four families were frequently represented: carangidae (Trachurus trachurus, T. trecae and Decapterus rhonchus); clupeidae (Sardina pilchardus, Sardinella aurita and S. maderensis); scombridae (Scomber japonicus); and lately, trichiuridae (Trichiurus lepturus). Using empirical orthogonal function analysis, it was shown that the study area is a transition zone between permanent upwelling in the north (20-25$\sp\circ$N) and regions with seasonal upwelling in the south (10-16$\sp\circ$N). Also, from 1985 …

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The Life History (Age, Growth And Reproduction) Of Red Snapper (Lutjanus Campechanus) And Its Affinity For Oil And Gas Platforms., Jeffrey Howard Render Jan 1995

The Life History (Age, Growth And Reproduction) Of Red Snapper (Lutjanus Campechanus) And Its Affinity For Oil And Gas Platforms., Jeffrey Howard Render

LSU Historical Dissertations and Theses

The purpose of this dissertation was to describe the association of red snapper, Lutjanus campechanus, with oil and gas platform habitat in the northern Gulf of Mexico. Ages were estimated using transverse sections of sagittae. Annuli were validated to have formed yearly. Age estimates ranged from less than 1 to 54 years. Von Bertalanffy growth models were significantly different for males and females; females exhibited a faster initial growth rate but achieved a lesser maximum length than did males. The variability in age among individuals of a given length or weight class precluded formulation of age at size keys. Otolith …

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Daily Variations Of Lipogenic Activities In Japanese Quail (Coturnix Coturnix Japonica)., Bruce L. Tedford Jan 1995

Daily Variations Of Lipogenic Activities In Japanese Quail (Coturnix Coturnix Japonica)., Bruce L. Tedford

LSU Historical Dissertations and Theses

Studies were made in Japanese quail (Coturnix c. japonica) to determine if daily variations of plasma insulin and de novo lipogenesis exists and examine the roles of daily variations in lipogenic responsiveness to insulin and prolactin. A daily variation in plasma insulin levels exists in quail fed ad libitum, with photophase levels 4.6 times greater than scotophase levels. This variation was not driven exclusively by the feeding of the quail, because insulin levels had dropped by dark onset, yet all bird's crops contained food at this time. There was a daily variation in the amount of $\sp{14}$C-acetate labelled lipids extracted …

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The Role Of Fecal Pellets In The Flux Of Carbon To The Sea Floor On A River-Influenced Continental Shelf Subject To Hypoxia., Naureen Aziz Qureshi Jan 1995

The Role Of Fecal Pellets In The Flux Of Carbon To The Sea Floor On A River-Influenced Continental Shelf Subject To Hypoxia., Naureen Aziz Qureshi

LSU Historical Dissertations and Theses

The Louisiana continental shelf near the Mississippi and Atchfalaya River deltas is a stratified and highly productive coastal system characterized by the largest hypoxic (dissolved oxygen $<$2 mg l$\sp{-1}$) zone in the western Atlantic Ocean. Carbon export from surface waters in the form of sedimenting zooplankton fecal pellets was examined to determine its importance in the formation and maintenance of oxygen deficiency in the bottom waters. Two sediment traps (5-6 and 15 m) were deployed in 1991 and 1992 in 20 m water depth within an area of chronic and seasonally severe hypoxia. I determined the fecal pellet number and carbon flux, and total carbon flux from the surface waters, the percent primary production exported as fecal pellets, and the potential for fluxed fecal pellet carbon to support bottom water hypoxia. I also quantitatively sampled the water column at discrete depths for fecal pellets and zooplankton to determine potential source organisms and their seasonal, diel and spatial variation. The highest densities of total organisms, copepods and copepod nauplii occurred during March and April (1992), when chlorophyll a concentrations in surface waters were highest, and decreased in summer and fall. The abundance of fecal pellets was positively correlated with total organisms, copepods and copepod nauplii, the likely source of fecal pellets. The fluxes of total particulate material, organic carbon, organic nitrogen, fecal pellet carbon and phytoplankton carbon varied similarly between seasons, and was lowest in summer and highest in spring. The fluxes were greater in 1991 than in 1992. Seasonal variations in fecal pellet number and carbon flux were positively correlated with indicators of high surface water productivity in 1991, but not in 1992. The flux of fecal pellets from surface to bottom waters accounted for 55% of the particulate material exported vertically, exceeded phytoplankton carbon fluxes, and was high enough to deplete the bottom water oxygen reserves in spring. The results support the hypothesis that the development of summer hypoxia is associated with the decomposition of organic matter accumulated in spring primarily by the sedimentation of a phytoplankton bloom via fecal pellets, and not as intact phytoplankton cells.

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Effects Of Environmental Factor Gradients On Survival, Growth And Physiology Of Two Species Of Crab Within The Genus Callinectes., John Louis Guerin Jan 1995

Effects Of Environmental Factor Gradients On Survival, Growth And Physiology Of Two Species Of Crab Within The Genus Callinectes., John Louis Guerin

LSU Historical Dissertations and Theses

Effects of environmental factor gradients on growth, molting and physiology of crabs within the genus Callinectes were examined. Juvenile blue crabs, Callinectes sapidus, were exposed to a range of dissolved cadmium concentrations at two salinities (2.5 and 25$\perthous$). 21-day LC$\sb{50}$'s were lower at 2.5$\perthous$ (19 $\mu$g l$\sp{-1}$) than at 25$\perthous$ (186 $\mu$g l$\sp{-1}).$ Crabs were exposed to Cd levels of 0, 50 and 100 $\mu$g l$\sp{-1}$ for bioenergetic measurements. Energy expenditure did not vary with cadmium. Scope for growth, energy consumption and energy absorption were unaffected by Cd at 25$\perthous,$ but decreased with exposure to cadmium at 2.5$\perthous.$. Juvenile lesser …

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Nitrogen Biogeochemistry Of Aquaculture Pond Sediments., John Albert Hargreaves Jan 1995

Nitrogen Biogeochemistry Of Aquaculture Pond Sediments., John Albert Hargreaves

LSU Historical Dissertations and Theses

Aquaculture pond water quality is dominated by planktonic processes, although the high surface-to-volume ratio suggests that sediment has the potential to effect important changes in water quality. The objectives of this research were to evaluate annual variation of sediment nitrogen biogeochemistry and develop a model of annual variation in ammonia concentration in a commercial channel catfish pond. In addition, the effects of physical and chemical sediment management techniques on water quality in aquatic mesocosms were evaluated. Sediment nitrogen was dominated by organic (92-96%) and adsorbed ammonium (2-4%) fractions. Porewater ammonium comprised the smallest yet most dynamic component of sediment N, …

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Estimation Of Genetic Parameters For Preweaning Growth Traits Of Crossbred Cattle., Denis Jose Salgado-Fonseca Jan 1995

Estimation Of Genetic Parameters For Preweaning Growth Traits Of Crossbred Cattle., Denis Jose Salgado-Fonseca

LSU Historical Dissertations and Theses

Data from a long-term rotational crossbreeding study involving Angus, Brahman, Charolais and Hereford cattle were analyzed to evaluate the importance of maternal effects on birth weight (BWT), weaning weight (WWT) and preweaning average daily gain (ADG) and, to estimate genetic parameters. Six different animal models were fitted for each trait, ranging from a single additive to a maternal animal model allowing for both genetic and environmental maternal effects and a genetic covariance between direct and maternal additive effects. Genetic effects were obtained using a maternal animal model allowing for a maternal additive effect and a direct-maternal additive covariance (Model 4). …

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Intraspecific Variation In Salt Tolerance In Panicum Hemitomon, Spartina Patens, And Spartina Alterniflora: Population Differentiation And Investigations Of Underlying Factors., Mark Warner Hester Jan 1995

Intraspecific Variation In Salt Tolerance In Panicum Hemitomon, Spartina Patens, And Spartina Alterniflora: Population Differentiation And Investigations Of Underlying Factors., Mark Warner Hester

LSU Historical Dissertations and Theses

Although it is known that wetland plant species exhibit considerable interspecific variation in salt tolerance across coastal plant communities, very little is known concerning the amount of intraspecific variation in salt tolerance within plant species. Panicum hemitomon, Spartina patens and Spartina alterniflora are dominant emergent macrophytes of fresh, brackish and salt marshes, respectively. To investigate intraspecific variation in salt tolerance, plant material was collected from Gulf Coast populations of each of these species and subjected to a salinity screening protocol. All three of the plant species displayed significant intraspecific variation in lethal salinity level and plant morphology. Lethal salinity levels …

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The Molecular And Morphological Systematics Of Subfamily Epidendroideae (Orchidaceae)., Malcolm Ray Neyland Jan 1995

The Molecular And Morphological Systematics Of Subfamily Epidendroideae (Orchidaceae)., Malcolm Ray Neyland

LSU Historical Dissertations and Theses

The current project undertakes the first molecular-based phylogenetic study of subfamily Epidendroideae (Orchidaceae). Approximately 1,200 nucleotide bases (from the 3$\sp\prime$ half of the ndhF chloroplast gene) for 34 orchid taxa, and a lilioid monocot, Clivia miniata, (Amaryllidaceae) were subjected to phylogenetic analysis using parsimony methods. Oryza sativa (Poaceae), a nonlilioid monocot was designated as outgroup. Using unweighted ndhF sequences, the strict consensus cladogram of 531 most-parsimonious trees supports the hypothesis that the large subfamily Epidendroideae is monophyletic, with Listera (Neottieae) as sister. Although subtribal-level relationships in subfamily Epidendroideae ate well resolved in this analysis, tribal-level relationships are resolved poorly. A …

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A Comparison Of Ecological Factors Affecting Two Species Of Lotic Molluscs., Paul David Johnson Jan 1995

A Comparison Of Ecological Factors Affecting Two Species Of Lotic Molluscs., Paul David Johnson

LSU Historical Dissertations and Theses

This study examined habitat-mediated differences in the population structure of two species of stream molluscs, the Louisiana pearl-shell mussel, Margaritifera hembeli, a protected species, and Elimia semicarinata, a pleurocerid gastropod. In 1991 I located Margaritifera hembeli in a drainage system where it was previously unknown, and describe here the distribution of M. hembeli in the Bayou Rigolette drainage in Grant Parish, Louisiana. The mussel was limited to small second- and third-order lotic systems. Of several physicochemical and habitat parameters, specific conductance, Ca$\sp{+2}$ concentration, sediment particle size, sediment compaction and channel width were most important in explaining abundance. Substratum stability was …

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Management Of Bollworm, Helicoverpa Zea (Boddie), And Tobacco Budworm, Heliothis Virescens (F.), With Transgenic Bt Cotton Genotypes, Microbial Insecticides And Conventional Insect Resistance Traits In Cotton., Charles Andrew White Jan 1995

Management Of Bollworm, Helicoverpa Zea (Boddie), And Tobacco Budworm, Heliothis Virescens (F.), With Transgenic Bt Cotton Genotypes, Microbial Insecticides And Conventional Insect Resistance Traits In Cotton., Charles Andrew White

LSU Historical Dissertations and Theses

Studies were conducted to determine the effectiveness of Bacillus thuringiensis (Bt) insecticides and transgenic Bt cotton in controlling the bollworm (BW), Helicoverpa zea (Boddie) and tobacco budworm (TBW), Heliothis virescens (F.), complex. Laboratory tests indicated that rates $\ge$1.17 liters (form)/ha caused TBW mortality significantly higher than the untreated control 2 hours after treatment (HAT). Dipel ES$\sp\circler$ at 4.68 liters (form)/ha and Condor OF$\sp\circler \ge$ 0.58 liters (form)/ha caused significantly higher TBW mortality than the untreated control at 72 HAT. TBW mortality levels did not significantly increase as Dipel ES$\sp\circler$ or Condor OF$\sp\circler$ dosage rates increased. Results of a persistence study …

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Daughter Cells Of Saccharomyces Cerevisiae From Old Mothers Display A Reduced Life Span, Nicanor Austriaco, Brian K. Kennedy, Leonard Guarente Dec 1994

Daughter Cells Of Saccharomyces Cerevisiae From Old Mothers Display A Reduced Life Span, Nicanor Austriaco, Brian K. Kennedy, Leonard Guarente

Biology Faculty Publications

The yeast Saccharomyces cerevisiae typically divides asymmetrically to give a large mother cell and a smaller daughter cell. As mother cells become old, they enlarge and produce daughter cells that are larger than daughters derived from young mother cells. We found that occasional daughter cells were indistinguishable in size from their mothers, giving rise to a symmetric division. The frequency of symmetric divisions became greater as mother cells aged and reached a maximum occurrence of 30% in mothers undergoing their last cell division. Symmetric divisions occurred similarly in rad9 and ste12 mutants. Strikingly, daughters from old mothers, whether they arose …

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Newsletter, University Of South Florida Botanical Garden Newsletter, December 1994, University Of South Florida. Botanical Gardens Dec 1994

Newsletter, University Of South Florida Botanical Garden Newsletter, December 1994, University Of South Florida. Botanical Gardens

USF University Archives and Documents

December 1994 newsletter of the University of South Florida Botanical Gardens. Topics include membership, Board of Advisors appointments, programming, new facility design, the USF Herbarium, plant facts, newly acquired plants, and event calendar.

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