The effect of lactic acid on the outer membrane permeability of Escherichia coli O157:H7, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium was studied utilizing a fluorescent-probe uptake assay and sensitization to bacteriolysis. For control purposes, similar assays were performed with EDTA (a permeabilizer acting by chelation) and with hydrochloric acid, the latter at pH val...

A comparative study of various treatments for inhibition of the residual activity of a lipase (obtained from Bacillus coagulans MTCC-6375) in a colorimetric assay using p-nitrophenyl palmitate (pNPP) was made. Direct chilling of contents of reaction mixture or addition of chilled mixture of ethanol : acetone (1:1) decreased the residual lipase activity by 94.0 and 95.0% respectively, as compare...

A dipeptidy} cftrbexypeptidase (DCP) activity was detected in cell-free extracts of Pseudomonas sp. W024. After purification and characterization the enzyme was found to be homogeneous by SDS-PAGE, and had a molecu)ar mass of 74,eOODa by SDS-PAGE and 72,OOODa by gel filtration, i dicating that it is monomeric. The isoeleenic point was 5.2 and optimum pH was 6.5-7.0. It showed a specific activit...

Human red blood cell ghosts were prepared by dielectric breakdown of the cell membrane and subsequent electrical haemolysis in isotonic and isoionic solutions. Almost complete removal of haemoglobin (to about 0.1%) could be achieved by subjecting the erythrocytes suspended in isotonic solution to three consecutive electric field pulses of 16 kV/cm in the presence of 10 mM EDTA, followed by dilu...

Monoclonal antibodies to human protein S have been prepared using established hybridoma technology. One antibody was isolated that binds protein S only when Ca2+ is present; others bind antigen equally well in the presence or absence of EDTA. Other antibodies display a diminished affinity for protein S in the presence of EDTA. Purified immunoglobulins from cell lines displaying Ca2+ dependence ...

In order to understand the mechanism of the post-translational processing of bone phosphoproteins in embryonic bone, periosteal bone strips isolated from 12-day-embryonic-chick tibiae were cultured and the bone proteins labelled with Na2H32PO4. Of the total radiolabelled proteins recovered from the medium and bone extracts in the absence of SDS ('medium', 'EDTA extract' and 'EDTA/guanidinium ch...

Legionella pneumophila, the etiologic agent of Legionnaires' disease, is phagocytized in an unusual way and multiplies in human mononuclear phagocytes in a novel phagosome. As a first step toward understanding these L. pneumophila-phagocyte interactions, we have studied the envelope of L. pneumophila Philadelphia 1 strain. We isolated cell envelopes by treating whole bacterial cells with lysozy...

Materials. Acrylamide, bisacrylamide, SDS, Tris, ammonium persulfate, sucrose, and Coomassie Brillant Blue R-250 were obtained from Bio-Rad Laboratories, Richmond, Calif. EDTA and 2-mercaptoethanol were obtained from Sigma Chemical Co., St. Louis, Mo. Hanks' balanced salt solution was obtained from the Grand Island Biological Co., Grand Island, N. Y. Ficoll was obtained from Pharmacia Fine Chem...

The protease from Chromohalobacter japonicus BK-AB18 was produced by growing bacteria in a LB medium containing 5% casein and NaCl. crude partially purified three levels of ammonium sulfate concentration (ranges 0–70%, 70–75% 75–80%) the highest specific activity exhibited range 75–80%. enzyme has relative molecular weight 65 kDa. this fraction had following optimum conditions: 7.5% NaCl, pH 9....