Browsing by Subject "Bacillus thuringiensis"
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Item A comparison of methods for activation of Bacillus thuringiensis and Bacillus cereus(Texas Tech University, 1985-08) Riley, Bryan ScottNot availableItem A comparison of sulfhydryl active compounds on activation and germination of Bacillus thuringensis spores(Texas Tech University, 1987-08) McQueen, Cynthia AnneSpores of Bacillus thuringiensis HD-1 and Bacillus cereus 569 were incubated in various sulfhydryl active compounds in order to compare the effects of these compounds on activation and germination. The sulfhydryl active compounds used were oxidized lipoic acid and cystine (S-S), cysteine HCl and dithiothreitol (S-H). B^. thuringiensis spores incubated in cysteine HCl had a substantially lower germination rate compared to spores incubated only in Tris pH 7.5 buffer. \^en B^. thuringiensis spores incubated in cysteine HCl were washed, they continued to exhibit this lower germination rate. Heat shocked B^. thuringiensis spores also showed a decrease in the germination rate when incubated in cysteine HCl. Comparison of B^. thuringiensis spores incubated in cysteine HCl and untreated B^. cereus spores shows the B^. thuringiensis spores decrease in germination approaching that of untreated B^. cereus spores. Heat activated spores of both B^. thuringiensis and B^. cereus had decreased germination rates when incubated in dithiothreitol compared to spores incubated in Tris pH 7.5 buffer. Heat activated B^. cereus spores incubated in lipoic acid had a lower germination rate when compared to untreated spores, while lipoic acid had no effect on heat activated B^. thuringiensis spores. These results suggest that B^. cereus and B^. thuringiensis do differ in their spore coat proteins. The action of dithiothreitol and oxidized lipoic acid were related only to heat activated spores of B^. thuringiensis and B^. cereus. The effects of cysteine HCl on B^. thuringiensis indicate a difference in disulfide bridges in the outer spore coats of B^, thuringiensis and B^. cereus.Item Compartmentalization of metabolism in Bacillus thuringiensis(Texas Tech University, 1985-05) Akinwunmi, Oluwatoyin OluwafeyikemiThe compartmentalization of metabolism and the influence of amino acids and various substrates on the growth of Bacillus thuringiensis were studied. Carbon and nitrogen metabolism are compartmentalized only during vegetative growth when glucose is present in the medium, and it is pH-dependent. Organic nitrogen sources or compounds which can generate NADPH for incorporation of ammonium into glutamate were required for growth, sporulation, and crystal formation in minimal glucose-salts medium, designated BM. Abundant growth occurred when organic nitrogen sources such as glutamate, glutamine, arginine, proline, citrulline, ornithine, histidine, aspartate, and asparagine were utilized as the sole sources of carbon and (or) nitrogen at O.OIM concentration. Other organic nitrogen sources able to support growth as carbon and (or) nitrogen sources at equimolar concentrations were alanine, valine, leucine, serine, methionine, lysine, and isoleucine, but growth was less. Serine and gamma-aminobutyric acid (an NADPH generator) supported growth only as the sole sources of carbon. Also pyruvate, alphaketoglutarate, and citrate (an NADPH generator) supported growth of the organism as sole sources of carbon. Succinate, isocitrate, betahydroxybutyrate, and glyoxylate did not support growth as carbon and (or) nitrogen sources. A proposed scheme of the pathway for breakdown of these metabolites in B. thuringiensis is presented.Item Effect of temperature on the germination of spores of Bacillus cereus and Bacillus thuringiensis(Texas Tech University, 1986-08) Ching, Hsing-yianNot availableItem Evaluation of Bacillus thuringiensis technology in Texas corn production(Texas Tech University, 2003-12) Youngblood, Jay LeeNot available.Item Factors affecting poly-b-hydroxybutyrate synthesis and crystal formation in Bacillus thuringiensis(Texas Tech University, 1984-08) Hickerson, Steven LynnNot availableItem Factors Influencing the Activation and Germination of Bacillus Thuringiensis and Bacillus Cereus Spores(Texas Tech University, 1987-05) Tatarko, MatthewNot Available.Item Growth Studies of an Entomogenous Bacterium, Bacillus Thuringiensis(Texas Tech University, 1982-05) Reich, Delores JaneStudies of the entomogenous bacterium. Bacillus thuringiensis, revealed that the presence of starch in the medium, used as a carbon and energy source, stimulated growth. It was also shown that by limiting the concentration of peptone in the medium (less than .2595), the pH of the medium during growth and sporulation can be controlled. These observations may allow an increase in numbers of spores and crystals produced and a higher level of toxicity of the crystal.Item Physiological properties of Bacillus thuringiensis endospores(Texas Tech University, 1987-05) Wilson, Gary R.Through use of an ±n^ vitro model, survival of vegetative cells and spores of Bacillus thuringiensis within insect midgut conditions was tested. Vegetative cells would not grow in 0.1 M carbonate-buffered media above pH 9 and growth was severely impeded by incorporation of thioglycollate. Outgrowth of spores was inhibited by long-term exposure to pH 8.5 or above, but short-term exposure to carbonate buffer enhanced viable counts. A number of basic chemicals and buffers improved outgrowth with best results obtained with 0.1 M potassium carbonate at a pH of 10. The combination of trypsin, carbonate, and thioglycollate yielded the highest outgrowth rate observed. Germination rates of spores were optimized by heat shock or incubation with carbonate buffer, though most spores did not require activation for germination. To further investigate spore properties, spores from four modifications of tryptic soy agar, two low in glucose and two rich in glucose, were tested for viability and resistance to heat, UV light, and octanol. In addition, spore sizes and germination rates were determined. Spores from low-glucose media (type A spores) were smaller and less resistant to heat and UV light than were spores from high-glucose media (type B spores). Type A spores also were faster germinating and had a greater percentage viable spores than their counterparts from high-glucose media. The contributions of these traits toward adaptation to the ecological niche for spores produced within insects or within the soil is proposed.Item The metabolism of fermentation products by Bacillus thuringiensis during growth and sporulation(Texas Tech University, 1987-05) Benoit, Thomas GerardWhen Bacillus thuringiensis HD-1 is grown in a glucose-ryptonemineral salts broth either left unsupplemented or supplemented with 0.1 M potassium phosphate buffer (pH 7.2), the pattern of production and utilization of lactate, pyruvate, acetate, intermediates of the 2,3 butanediol cycle, and poly-betahydroxybutyrate are identical. Lactate is formed from the tryptone supplement in the early stages of growth while glucose is oxidized to pyruvate, which provides acetate for polybetahydroxybutyrate synthesis via the 2,3 butanediol cycle. A pH-control over pyruvate utilization is absent. A pH effect is observed as less lactate and pyruvate are produced in unbuffered broth and utilization of glucose and acetate is slower in unbuffered medium. The results indicate that Bacillus thuringiensis HD-1 lacks the activity of pyruvate dehyrogenase or phosphate acetyltransferase. L-malate may serve as a hydrogen sink for the regeneration of NAD from NADH.