Digital Commons Network^™

Host-Cell Mediation Of Murine Hepatitis Virus (Mhv) Persistence, Lee Alan Mizzen

Digitized Theses

An in vitro study was undertaken to characterize the mechanisms by which the coronavirus, mouse hepatitis virus (MHV), mediates persistent infection. MHV persists in cultures of mouse fibroblast LM cells (designated LMTK('-)), but produces a lytic infection in L-2 cells. Persistence in LMTK('-) cells was not accompanied by the production of virus mutants nor soluble antiviral factors. Rather, LMTK('-) cells possess two characteristics which allow cultures to support MHV persistence: a reduced level of initial infectability, and a resistance to virus-induced cell fusion. Similar host-cell determinants were found to be operative in persistent MHV infection of another mouse LM cell …

Factors Governing Patterns Of Brood Defense In Male Smallmouth Bass (Micropterus Dolomieui), Mark Stephen Ridgway

Digitized Theses

I examined the effects of offspring stage, brood size, and parental age on the patterns of brood defense in nesting male smallmouth bass (Micropterus dolomieui), a centrarchid fish with male parental care, in Lake Opeongo, Ontario. Parental defense against conspecific models of equal length ((+OR-)1 cm) was used as a measure of parental commitment to the brood. Based on Williams' principle, or the trade-off between present and future reproduction, parental males should adjust their level of brood defense to reflect the value of current offspring relative to their expected future reproduction.;Parental defense increased as a model intruder approached the nest …

Characterization Of Heat-Shock And Chemical-Stress Induced Changes In The Gene Expression Of Mammalian Lymphocytes, David Ivan Rodenhiser

Digitized Theses

To investigate the effect of heat-shock (HS) on the gene expression of mammalian blood cells, human, mouse and rabbit blood cells were cultured and incubated at elevated temperatures or in the presence of ethanol or sodium arsenite, and the patterns of polypeptides synthesized by these cells analyzed by one- and two-dimensional polyacrylamide gel electrophoresis (PAGE). The in vitro exposure of human lymphocytes or human myeloma cells to short term increases in incubation temperature (41(DEGREES) - 43(DEGREES)C) results in the enhanced synthesis of heat-shock proteins (HSPs) of 110, 100, 90, 70 and 65 kilodaltons, and the depressed synthesis of many polypeptides …

Developmental Regulation Of Protein Synthesis In Hymenolepis Diminuta, Afzal Ahmed Siddiqui

Digitized Theses

Protein synthesis and its regulation was studied for the first time in the rat tapeworm, Hymenolepis diminuta, during strobilization. Parasites were metabolically labelled with ('35)S-methionine and the pattern of gene products synthesized was obtained for the scolex/neck region, male proglottids, female proglottids and onchospheres by high resolution 2-dimensional polyacrylamide gel electrophoresis and fluorography. Gene products unique to different sexually differentiated proglottids were localized to the nuclear, brush border, mitochondrial, microsomal and cytosolic fractions obtained by detergent treatment and osmotic shock, followed by differential centrifugation. The purity of different fractions was monitored by transmission electron microscopy and enzyme marker studies. Total …

Variations In The Biennial Life History Strategy Among 15 Ruderal Species In An Abandoned Gravel Pit Near London, Ontario, Paul Frederick Threadgill

Digitized Theses

Fifteen biennial species co-existed in an abandoned gravel pit near London, Ontario. Investigations were performed to identify variations in their regeneration characteristics. Once identified, variations were compared to attempt to explain these species' co-existence in this habitat. Mean net seed production per plant, mean seed weight per species, and dispersal of diaspores by wind, water, and animals were determined for each species. Mean seed production per plant ranged from 119 to 22,425. Mean weight per seed per species ranged from 0.07mg to 13.03mg. Mean weight per seed varied throughout the growing season in each of thirteen species. Diaspores of eight …

Anti-Mosquito Behavior Of Adult And Juvenile White-Footed Mice (Peromyscus Leucopus) (Treehole Mosquito, Aedes Triseriatus, Epidemiology), Connie Isaacs

Doctoral Dissertations

Rodents seldom are identified as hosts for mosquitoes, based on serological analysis of bloodmeals. However, due to limited survey and lack of sensitivity in most bloodmeal analyses, host species can be misrepresented or undetected. Knowledge of behavior of a potential host species can complement results of bloodmeal analysis, because active vertebrates may prevent mosquito feeding and thus rarely serve as hosts. The objectives of this study were to characterize anti-mosquito behavior in the white-footed mouse (Peromyscus leucopus noveboracensis) and to examine effectiveness of such behavior in mice based on age, prior exposure to mosquitoes, and immediate environment.

I used wild-stock …

A Mouse Model Of Bovine Pneumonic Pasteurellosis: Dose Response, Temporal Evolution Of Lesions And Effects Of Arachidonic Acid Inhibitors (Indomethacin, Nordihydroguaiaretic Acid, Hydroxyurea)., Lanny Wade Pace

LSU Historical Dissertations and Theses

Outbred Swiss Webster mice were used as an experimental model for bovine pneumonic pasteurellosis. Using light microscopy and transmission electron microscopy to evaluate lesions, it was determined that intrabronchial inoculation of Pasteurella haemolytica serotype 1 induces dose dependent pulmonary lesions in the mouse. Five x 10('7) colony forming units was the optimum dose which induced lesions and allowed survival for at least 24 hours. Using the optimum dose of inoculum, lesions were evaluated at different time points to determine when neutrophil influx into the lung first occurred. Four hours post inoculation was the minimum time required for neutrophil influx to …

Population Dynamics Of The Monogenea (Platyhelminthes) On The Bluegill, Lepomis Macrochirus, In Southern Louisiana., Leon F. Duobinis-Gray

LSU Historical Dissertations and Theses

Seven species of Monogenea of the subfamily Ancyrocephalinae were collected from 700 Lepomis macrochirus from two eutrophic localities in southern Louisiana. Host specimens were collected monthly from May 1982 through April 1984 from Pat's Bay and Spanish Lake. The relative densities of nonlarval Onchocleidus ferox, Actinocleidus fergusoni, Haplocleidus acer, H. dispar, Anchoradiscus triangularis, Cleidodiscus robustus, and C. nematocirrus were analysed for correlation with water temperature, significant differences in locality, temporal and spatial dynamics, and effect of host sex on population densities. The three more abundant species, O. ferox, A. fergusoni, and H. acer, were warm-water forms, whereas H. dispar and …

Schistosomiasis A Public Health Concern, Greg Maciel

Whittier Scholars Program

This project is a research paper on the parasitic disease, schistosomiasis. Schistosomiasis can cause illness, disability, and in some cases, death. Schistosomiasis survives in climates that range from tropical to temperate. The disease is most prevalent in underdeveloped areas where sanitation is poor. These underdeveloped areas have little money for treatment and controls. And because the disease prevents people from working, the economy of these infected areas can suffer. Without eradication efforts, schistosomiasis can be spread to the whole population. In trying to control schistosomiasis people are looking for the most thorough and least expensive methods. This paper will be …

Antifreeze Production And Cold-Tolerance In Overwintering Purple Martin Fleas, Ceratophyllus Idius Jordan And Rothschild (Cryo-Protectants, Hardiness)., Douglas P. Schelhaas

Theses and Dissertations

Ceratophyllus idius is an ectoparasite of purple martins (Progne subis) and commonly inhabits the nest material of these birds. In the Upper Midwest, purple martins migrate in late August and return in mid- or late April. Despite the host's absence and harsh northern winters, a portion of the adult flea population survives to reinfest returning birds. This study was designed to: (1) examine the possible roles of sorbitol and trehalose as biological antifreezes; (2) confirm the role of glycerol as an antifreeze; (3) monitor glycogen and glycerol levels and supercooling points from autumn until spring; (4) determine the temperature stimulus …

The Effects Of Heartworm Infection And Beta Blockade On Submaximal, Graded Exercise In Dogs., Patricia Louise Hopkins Price

LSU Historical Dissertations and Theses

Four dogs with canine heartworm disease (CHD) and four control dogs were tested during a 21 minute submaximal, incremental, graded treadmill test, under normal conditions and after 2 mg/kg propranolol, i.v. Arterial and venous blood gas and pH, heart rate, systemic blood pressure, hematocrit, rectal temperature, lactate, glucose, and electrolytes were measured. CHD dogs had lower sodium and P(,a)O(,2) levels. All dogs displayed progressive increments in heart rate, hematocrit, and potassium and small gains in rectal temperature during exercise. Mean arterial blood pressure (MABP) and arterial pH increased and remained elevated throughout exercise. P(,v)O(,2) and P(,a)CO(,2) decreased, but P(,a)O(,2) did …

Molecular Studies Of T-Lymphocytes From Bovine Leukemia Virus-Infected Cattle., Diana Lynn Williams

LSU Historical Dissertations and Theses

Highly specific monoclonal antibodies and microfluorimetry were used to determine the absolute number of B and T lymphocytes in the peripheral blood of bovine leukemia virus (BLV) infected cattle. The peripheral blood lymphocyte populations from BLV-infected cattle were elevated when compared to BLV-negative animals. The increase in the lymphocyte population in the aleukemic (AL) animals was due to an increase in T lymphocytes. In the PL animals the increase was due mainly to an increase of B lymphocytes but also to an increase of T lymphocytes. The PL animals showed a significantly higher number of surface immunoglobulin positive cells (sIg('+)) …

Studies On The Molecular Cloning Of "Aryletherase" From A Ligninolytic Erwinia Sp.: Enhancement Of Gene Expression., Jeffrey William Cary

LSU Historical Dissertations and Theses

Recombinant DNA techniques were used to enhance the expression of a gene encoding "aryletherase" activity. This gene, apparently lacking regulatory elements, was present on a 792bp BamHI DNA fragment of Erwinia sp. genomic DNA, that was cloned into Escherichia coli using the plasmid vector pBR322. To obtain a larger fragment of Erwinia genomic DNA carrying the "aryletherase" gene and its regulatory regions, an Erwinia sp. genomic DNA library was constructed in the lambda phage EMBL3. Screening the library with nick translated 792bp BamHI fragment identified several recombinant phage which demonstrated homology with the probe. Restriction digestion of DNA from one …

Characterization Of Messenger Ribonucleoprotein Particles In Dormant Sporangiospores Of The Fungus Mucor Racemosus (Messenger-Rna)., Charles Patrick Chapman

LSU Historical Dissertations and Theses

Extracts of sporangiospores of Mucor racemosus contained RNA that readily hybridized with ('3)H polyuridylic acid. Prior to germination, this RNA was in a form sedimenting at <80S. Within 10 minutes after initiating germination, most of this RNA sedimented with polyribosomes and 80S monoribosomes. Particulate material from spore extracts bound to oligo dT -cellulose at high ionic strength and was assumed to contain messenger ribonucleoprotein particles (mRNP's). A portion of the mRNP's was released from the column by lowering the ionic strength. Other portions were eluted stepwise in buffer containing 50% and 90% formamide and in 0.1-N NaOH. Identical elution patterns were observed whether monitoring incorporated ('31)P-orthophosphate or L- ('32)S methionine, absorbance at 280 nm, or hybridization of ('3)H polyuridylic acid. mRNP's from the first two fractions were analyzed. A bimodal population of particles was detected in sedimentation velocity and sedimentation equilibrium centrifugation. Particles eluted at low ionic strength demonstrated a sedimentation coefficient distribution of 20S-to-80S, with a mean of 55S. Particles eluted in formamide demonstrated a sedimentation coefficient distribution of 20S-to-60S, with a mean of 40S. Particles eluted at low ionic strength displayed two peaks in CsCl centrifugation, with bouyant densities of 1.37 gm/cc and 1.59 gm/cc. Particles eluted in formamide displayed a single peak with a buoyant density of 1.61 gm/cc. Particles eluted at low ionic strength and centrifuged in metrizamide solution formed two bands having bouyant densities of 1.15 gm/cc and 1.30 gm/cc; formamide-eluted particles banded only at the higher density. Mucor 40S ribosomal subunits banded at 1.56 gm/cc and 1.28 gm/cc in CsCl and metrizamide solution respectively. Analysis of mRNP fractions by sodium dodecylsulfate-polyacrylamide gel electrophoresis characterized protein components of these particles which helped explain their biomodal sedimentation behaviour. Each mRNP fraction contained a unique spectrum of proteins not shared by ribosomes or soluble cell proteins. The formamide-eluted particles contained two proteins, whereas the particles eluted at low ionic strength possessed 12 proteins. A 24,000-dalton protein was the predominant form in both. The denser mRNP's were smaller and lacked proteins found in the larger less dense particles. The former had a protein/RNA ratio of 45/55; whereas the later possessed a value of 90/10. Messenger RNA extracted from the mRNP's sedimented between 8S-to-20S.

Genomic Organization And Sequence Analysis Of Rabbit Muscle Phosphofructokinase Gene., Chan Ping Lee

LSU Historical Dissertations and Theses

A rabbit genomic clone containing the muscle phosphofructokinase (PFK) gene of approximately 17 kilobase pairs encoding 779 amino acids was isolated and sequenced. This gene contains 22 exons, ranging from 45 to 190 base pairs, and is split by 21 introns of 73-3500 base pairs. Eighty six percent of this gene is occupied by introns. An additional incomplete intron is found in the 5' flanking region, while an Alu-like sequence is identified in the 3' flanking region. The amino acid sequence translated from the coding sequence of this gene reveals 29 residues (amino acid numbers 479-507) which complete a previously …

Glyphosate Catabolism By Pseudomonas Sp. Pg2982., Dean Lee Shinabarger

LSU Historical Dissertations and Theses

The pathway for the degradation of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. PG2982 has been determined using metabolic radiolabeling experiments. Radiorespirometry experiments utilizing 3-('14)C glyphosate revealed that approximately 50-59% of the C3 carbon was oxidized to CO(,2). Fractionation of stationary phase cells labeled with 3-('14)C glyphosate revealed that from 45-47% of the assimilated C3 carbon is distributed to proteins and that the amino acids methionine and serine are highly labeled. The nucleic acid bases adenine and guanine received 90% of the C3 label that was incorporated into nucleic acids, and the only pyrimidine base labeled was thymine. These results indicated that …

Tolerance, Bioenergetics And Biochemical Composition Of The Blue Crab, Callinectes Sapidus Rathbun, Exposed To The Water-Soluble Fraction Of South Louisiana Crude Oil., Shiao Yu Wang

LSU Historical Dissertations and Theses

The tolerance, bioenergetics, growth, molting frequency and biochemical composition of juvenile blue crabs, Callinectes sapidus, exposed to the water-soluble fraction of South Louisiana crude oil were determined during a 21-d exposure period. Blue crabs were highly tolerant to petroleum hydrocarbons; the LC50 was 3927 ppb on day 21. Rates of energy intake decreased with increasing hydrocarbon concentration. Although energy expenditure rates of crabs exposed to 2504 ppb were not significantly higher than that of control crabs, they were significantly higher than those of crabs exposed to 820 and 1476 ppb. The resulting decrease in scope for growth was thus due …

The Hepatotoxicity And Urinary Metabolites Of 2,4- And 2,6-Dimethylaniline In The Rat And Dog (Aromatic Amines)., Marcia L. Hardy

LSU Historical Dissertations and Theses

This study was designed to investigate the hepatotoxicity and urinary metabolites of 2,4- and 2,6-DMA in the dog and rat and the covalent binding of the two isomers in the rat as differences in metabolism may be related to the divergent hepatic responses. Male Beagles were orally dosed for 1 or 10 days with 2,6- or 2,4-DMA at 25 mg/kg. Male Fischer 344 rats were gavaged with 2,6- or 2,4-DMA at 25% of their respective LD50's (262.5 mg/kg; 117/mg/kg) for the same time period. The effects of phenobarbital (PB), 3-methylcholanthrene (3MC) and SKF-525A on the hepatotoxicity and metabolites of 2,4- …

Facilitative And Inhibitory Interactions Among Estuarine Meiobenthic Harpacticoid Copepods (Commensalism, Benthos, Louisiana)., George Thomas Chandler Ii

LSU Historical Dissertations and Theses

In Louisiana, USA, marshes, the harpacticoid copepods Scottolana canadensis and Pseudostenhelia wellsi are community co-dominants with similar lifestyles. Scottolana canadensis is a semi-sessile burrow-dweller capable of subsurface suspension and deposit feeding. Pseudostenhelia wellsi is a semi-sessile tube-building copepod that continuously corkscrews back and forth within its tube and appears to graze on the inner tube walls. Monospecific patches of both species (250 (.) 5cm('-2)) were generated in laboratory microcosms to determine their effects on colonization by two completely errant, burrowing harpacticoids, Nitocra lacustris and Cletocamptus deitersi, that have similar foraging and burrowing behaviors and similar effects on sediment structure. Pseudostenhelia …

Studies On The Molecular Cloning Of A Gene For Beta-Glucosidase From A Bacillus Cereus/Cellulomonas Sp. Hybrid Bacterium Derived Through Protoplast Fusion., Eun Soo Han

LSU Historical Dissertations and Theses

A (beta)-glucosidase gene was cloned from a cellulolytic bacterium, which was obtained by hybrid-formation between Bacillus cereus and a Cellulomonas sp. through protoplast fusion, into Escherichia coli plasmid pBR322 using recombinant DNA techniques. E. coli strain transformants of JM83 harboring this cloned plasmid were able to utilize cellobiose as a carbon source. (beta)-glucosidase activity was assayed in these cells by P-nitrophenyl (beta)-D-glucopyranoside (PNPG) hydrolysis. Hybridization of the cloned DNA fragment with DNA from the hybrid organism was performed by Southern transfer (92) and DNA/DNA dot blot procedures. The hybridization data strongly suggested that the DNA cloned into pBR322 was from …

Effect Of Experimental Ostertagia Ostertagi Infection Or Chronic Pentagastrin Treatment On Abomasal Pathophysiology And Morphology Of Goats., Judit Eva Markovits

LSU Historical Dissertations and Theses

European-type mixed-breed goat kids were infected with Ostertagia ostertagi or were given chronic pentagastrin treatment. Selected clinicopathological parameters and fecal egg counts were monitored throughout the study. At necropsy the abomasal physical parameters were recorded and tissue samples were saved for parasite recovery, quantitative and qualitative light microscopy and transmission and scanning electron microscopy. Serum pepsinogen and gastrin immunoreactivity increased in parasitized animals. The increase was associated with the tissue phase of the parasitic development. Pentagastrin did not alter pepsinogen or gastrin immunoreactivity. All 8 infected animals had patent infection, and approximately 5% establishment of the infective dose of 15,000 …

Benthic Microfloral Production On The West And Gulf Coasts Of The United States: Techniques For Analyzing Dynamic Data (Entropy Data Analysis)., Gary Paul Shaffer

LSU Historical Dissertations and Theses

The objective of this study was to compare benthic microfloral production on the west and gulf coasts of the U.S.A., and to determine what factors govern that production. Intensive, month long field studies were conducted at two sites in a salt marsh lagoon (Mugu Lagoon) in southern California and at two sites in a shallow water estuary (Barataria Estuary) in southwest Louisiana. For both studies, fluctuations in production during a single month approximated those measured previously over an entire year: daily production varied from 0 to 1500 mg C (.) m('-2). A comparison was made between the sources of error …

The Effect Of Temperature And Humidity Stress On Plasma Progesterone, Luteinizing Hormone And Cortisol Profiles Following Cloprostenol Injection In Cycling Holstein Cows In A Controlled Environment (Environmental Physiology, Reproduction, Prostaglandins)., Anandarajah Sri Kanda Kumar

LSU Historical Dissertations and Theses

The effect of heat stress on plasma profiles of progesterone, luteinizing hormone (LH) and cortisol was evaluated following cloprostenol (500 (mu)g) induced luteolysis in lactating and non-lactating cows in a controlled environment. Another experiment was conducted to evaluate the effect of heat stress on the superovulatory response in lactating cows. The plasma progesterone, LH and total estrogen concentrations were not altered by heat stress (P > 0.05) when the average rectal temperatures of both lactating and non-lactating cows were raised to 39.83(DEGREES)C (103.7(DEGREES)F). However, plasma cortisol was significantly suppressed (P < 0.05) during heat stress. Luteolysis was followed by a preovulatory LH surge in all cows following cloprostenol and thus heat stress did not appear to alter the responsiveness of the corpus luteum to cloprostenol and the factors which regulate the hypothalamic control of LH release. Preovulatory LH peaks were preceded by total estrogen peaks and therefore heat stress did not appear to alter the positive feedback of estrogens from the preovulatory follicles to release LH from the pituitary gland. The magnitude of the diurnal variation of cortisol was higher during lower stress. LH peaks were seen irrespective of cortisol concentrations during both higher and lower stress treatments. However, LH peaks coincided with those of cortisol and total estrogens during lower stress treatments in both lactating and non-lactating cows. An altered diurnal variation in rectal temperatures was seen following LH peaks during lower stress. Fifteen transferable embryos were recovered during lower stress (15/34 or 44%) compared to one transferable embryo (1/4 or 25%) during higher stress (P > 0.05) in the superovulation study. Thus it appears that heat stress …

Equine Herpesviruses Type 1 And 2: Growth And Cytopathic Expression In Organ Cultures Of Equine Respiratory Epithelium And In Cell Cultures (Electron Microscopy, Morphogenesis)., Emmanuel Eddie Brako

LSU Historical Dissertations and Theses

The pathogenesis of equine herpesvirus type 1 (EHV-1) and type 2 (EHV-2) respiratory infection was studied in cell and organ cultures by infectivity assays following experimental infections (growth kinetics), and by light, scanning and transmission electron microscopy. The cell cultures included fetal donkey and pony alveolar macrophages (FDAM/FPAM), fetal equine kidney (FEK), rabbit kidney (LLC-RK(,1)), and african green monkey kidney (VERO) cells. Organ cultures were derived from respiratory tissues (nasal, tracheal and pharyngeal mucosae) of seronegative donkey (F1D1) and pony (F1M1) fetuses, and of a seropositive adult pony (A1). In the cell cultures, EHV-1 multiplied and produced cytopathic effects (CPE) …

Circadian Lipogenic Responses To Insulin And Prolactin., Anthony Henry Cincotta

LSU Historical Dissertations and Theses

Lipogenic responsiveness to insulin was investigated at different times of day in freshly isolated hepatocytes and in primary cultured hepatocytes of Syrian hamsters, Mesocricetus auratus held on 14 hour daily photoperiods (lights on: 08.00) by following (('14)C)acetate incorporation into total cell lipid. The influence of prolactin on lipogenesis was tested by adding the hormone in vivo and directly to primary cultured hepatocytes. The findings of these studies are unique in that they demonstrate important roles of temporal interaction between prolactin and insulin in regulation of lipogenesis in cultured hepatocytes. They are summarized as follows: (1) A circadian variation of lipogenesis …

Functional Organization Of The Gustatory System In The Brains Of Ictalurid Catfish: A Combined Electrophysiological And Neuroanatomical Study (Taste, Viscerotopic, Sensory Maps, Forebrain)., Jagmeet Singh Kanwal

LSU Historical Dissertations and Theses

The present study utilizes electrophysiological and neuroanatomical techniques to investigate the functional organization of the gustatory system in the brainstem and the forebrain of the channel catfish, Ictalurus punctatus. Neuroanatomical studies indicate an overlapping, segmental pattern of projection of glossopharyngeal-vagal branches in the vagal lobe. The vagal nerve complex is divisible into an interoceptive input (consisting of general visceral fibers) from abdominal viscera and an exteroceptive-branchial component (consisting of special and general visceral fibers) innervating the oro-pharyngeal region. The interoceptive-visceral input converges onto the exteroceptive, oro-pharyngeal input in the nucleus intermedius of the vagal lobe (nIV). In addition, extra-oral and …

The Physiological Ecology Of A Migratory Noctuid Moth, The Velvetbean Caterpillar (Anticarsia Gemmatalis Hubner) (Density, Plant Age, Juvenile Hormone)., Howard William Fescemyer

LSU Historical Dissertations and Theses

Velvetbean caterpillars, Anticarsia gemmatalis Hubner, were reared at different densities on soybean. The degree of dark pigmen- tation was density-dependent under field and laboratory conditions. The highest degree of dark pigmentation was expressed in the last instar when larvae were crowded throughout development. Soybean plant age had no effect on the degree of dark pigmentation. Larval development was delayed and one-day-old adult weight was decreased as the larval density and plant age increased. Size and biochemical composition of one-day-old A. gemmatalis adults was investigated in relation to larval pigmentation, larval den- sity and plant age. Wet, dry and protein weights …

Damage Threshold And Sampling Methodology Of The Southern Green Stink Bug, Nezara Viridula (L.) On Fresh Market Tomatoes., Ben-Huai Lye

LSU Historical Dissertations and Theses

The effect of tomato fruit size and SGSB density and feeding duration on tomato circumference, weight, and days to maturity, as well as SGSB feeding frequency as indicated by the deposition of stylet sheaths, was quantified. Density and feeding duration had a significant effect on all four damage indices. The interactive effect of density and feeding duration were nonsignificant across all fruit damage indices. Feeding damage induced an early maturity of fruit and thereby reduced fruit size and weight. Both density and feeding duration significantly affected fruit grade. Because of highly significant interactions among grade, density, and feeding duration, the …

Plant Water Relations Of Four Coastal Louisiana Dune And Swale Species., Frank J. Monteferrante

LSU Historical Dissertations and Theses

Native vegetation has recently been planted to control erosion along the Louisiana Gulf coast. The literature has characterized the dune habitat as xeric and its vegetation as adapted to low moisture availability. To analyze the drought ecology of Louisiana's coastal dune vegetation, a one-year field investigation of plant water relations and subsequent greenhouse drought-stress experiments were performed on Spartina patens (Aiton) Muhl., Panicum amarum Ell., Hydrocotyle bonariensis Lam., and Solidago sempervirens L. In addition, the sources of soil moisture and edaphic parameters related to soil-moisture availability were investigated. The field investigation showed dune and swale soils to be mainly fine …

The Threecornered Alfalfa Hopper On Soybean: Determination Of Damaging Stages, Development Of Sampling Methodology, Refinement Of The Action Threshold, And Evaluation Of Insecticidal Control (Spissistilus Festinus, Glycine Max)., Alton Neal Sparks Jr

LSU Historical Dissertations and Theses

Experiments conducted in soybean, Glycine max (L.) Merrill, fields in 1983 and 1984 demonstrated that damage by both adults and nymphs of the second generation of the threecornered alfalfa hopper, Spissistilus festinus (Say), on soybean (third generation of the year) contribute to yield reduction. Results indicated nymphs were responsible for 45-60% of the total yield reduction. The vertical beat sheet, ground cloth, and beat net techniques for sampling S. festinus nymphs were evaluated in soybean fields utilizing systematic and random sampling. Based on the proportion of the population sampled, the relative variation, and regression on subsequent adult counts, the best …