No description available.

$ beta$-Galactosidase (E.C. 3.2.1.23) or lactase was produced by the growth of a selected Bacillus subtilis strain (KL88) which was adapted to grow at 10$ sp circ$C. The growth and enzyme production were maximal at 2% (w/v) lactose supplemented with 0.2% (w/v) yeast extract. A Fast Protein Liquid Chromatography system (FPLC) was used for $ beta$-galactosidase purification. The enzyme was purified to 44-fold over the crude extract with a recovery of $ sim$54%. Native-PAGE and SDS-PAGE using "PhastSystem" showed the presence of two isoenzymes having molecular weights of 88 and 170 kD. The purified enzyme showed high activity at low temperatures (10$ sp circ$C) and recorded an optimum pH of 7.0. The K$ sb{ rm m}$ values were found to be 2.21 mM and 28.08 mM for o-nitrophenyl-$ beta$-D-galactopyranoside (ONPG) and lactose, respectively. / $ beta$-Galactosidase from psychrotrophic Bacillus subtilis was specific to the $ beta$-D-glycosidic linkage normally present in lactose. / To investigate the possibility of producing proteinase-free $ beta$-galactosidase from this psychrotrophic microorganism, FPLC was used for the rapid separation of $ beta$-galactosidase.

The purpose of this study was to compare the pathology caused by two bacterial species, Bacillus subtilis and Bacillus thuringiensis, in European corn borer larvae. The study consisted of: (1) a determination of the mortality of larvae that had ingested various concentrations of bacterial spores; (2) light microscopic examination of midgut tissues of larvae treated with various concentrations of bacterial spores, and (3) examination of midgut tissues of treated larvae with transmission electron microscopy.The results of the mortality study indicated that B. subtilis did not cause mortality in corn borer larvae. Light and electron microscopy did not reveal any pathological damage to midgut tissues of larvae treated with B. subtilis. It was observed that there was an increase in the amount of peritrophic membrane produced in the larvae treated with B. subtilis. These larvae were also observed to be sluggish and have diahrrea, suggesting a mild disease state.Mortality in larvae treated with B. thuringiensis varied with the concentration of spores ingested, and ranged as high as 100 percent. The mortality data were used to select three spore concentrations, corresponding to 25 percent, 50 percent, and 90 percent mortality levels. Larvae treated with B. thuringiensis spores in these concentrations were then examined by light microscopy. The pathology observed included slight swelling and vacuolation of the epithelial cells, cellular disruption, and complete breakdown of the epithelial tissue and subsequent bacteremia. It was observed that the degree of pathology increased with an increase in the bacterial spore concentration.Electron microscopic examination of midgut of B. thuringiensis treated larvae revealed the following pathological symptoms: decrease in apical microvilli, decrease in microvilli of goblet cells, and decrease in basal infoldings of plasma membrane.

Apolipophorin-III (apoLp-III) is known to influence the haemocyte-mediated induction of antimicrobial peptides in Galleria mellonella and yeast phagocytosis, bind to Gram-negative and Gram positive bacteria and limit the activation of the haemocytes and the prophenoloxidase system by bacterial surface antigens. The effects of apoLp-III on haemocyte adhesion to glass slides and to bacteria were herein examined. ApoLp-III bound to haemocytes limiting the adhesion of both granular cells and plasmatocytes to glass and the contact of the plasmatocytes with Bacillus subtilis. The percentage of granular cells with bacteria was increased by the protein. However, the total number of bacteria adhering to haemocytes in vitro declined in the presence of apoLp-III. Bacterial removal from the haemolymph in vivo by the haemocytes was slowed by the protein. / The adhesion of both the granular cells and plasmatocytes to slides was decreased by inhibiting protein tyrosine kinase and increased by inhibiting protein kinase A (PKA) and protein kinase C (PKC) activity. The latter was confirmed with haemocytes inhibited by the general PKC inhibitor H-7 using phorbol-3-myfstate (PMA) which, by activating PKC, diminished the adhesion of both haemocyte types. Limiting the formation of PKC activation by diacylglycerides which is produced by phosholipase C (PLC), using PLC inhibitor also increased haemocyte attachment. Although binding of B. subtilis to haemocytes decreased PKC activity, the effect of apoLp-III on PKC was inconclusive.

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1968. / Bibliography: leaves 144-149. / xiv, 149 l illus., tables

Thesis (M.Sc.) -- University of Adelaide, Dept. of Biochemistry, 1981.

Thesis (Ph.D.)--Michigan State University. Cell and Molecular Biology Program, 2006. / Title from PDF t.p. (viewed on June 19, 2009) Includes bibliographical references. Also issued in print.

Thèse (Ph. D.)--Université Laval, 2007. / Titre de l'écran-titre (visionné le 9 mai 2008). Bibliogr.

Thesis (Inaug.-Diss.)--Universität Basel, 1896? / Bibliography: p. 33-34.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.