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Full-Text Articles in Medicine and Health Sciences
Aerotaxis In Bacillus Subtilis, Laurence Samuel Wong
Aerotaxis In Bacillus Subtilis, Laurence Samuel Wong
Loma Linda University Electronic Theses, Dissertations & Projects
B. subtilis, like Escherichia coli and Salmonella typhimurium, responded to a step increase in oxygen concentration by swimming smoothly (~ 35 s duration) and to a decrease in oxygen by tumbling. In a spatial gradient of oxygen in liquid media, a band of cells congregated near the air interface. Aerotaxis required a functioning respiratory chain. Adaptation of B. subtilis, E. coli and S. typhimurium to media containing amino acids requires methylation of receptors/methyl-accepting chemotaxis proteins. Adaptation to oxygen and phosphotransferase sugar substrates in B. subtilis was dependent on methylation, unlike similar adaptation in E. coli and S. typhimurium. …
The Distribution And Occurrence Of Aerobic Heterotrophic Antimicrobic-Producing Bacteria Isolated From The Lower Chesapeake Bay, Linda Lea Gilmer
The Distribution And Occurrence Of Aerobic Heterotrophic Antimicrobic-Producing Bacteria Isolated From The Lower Chesapeake Bay, Linda Lea Gilmer
Biological Sciences Theses & Dissertations
Three different estuarine microenvironments in the lower Chesapeake Bay were investigated for the occurrence and geographical distribution of antimicrobic-producing bacteria. Samples were taken from the water column, fish skin, and algal surfaces. A total of 1472 bacterial isolates were assayed for antimicrobial activity against fungal, Gram-negative and Gram-positive bacterial test organisms. Of the total bacterial isolates assayed, 5. 2% were active antimicrobic producers. Algal surf aces were shown to have a higher incidence of antimicrobic-producing bacteria than the water column or fish skin. No antimicrobic activity was demonstrated by bacteria isolated from the flounder fish skin. The majority of the …