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Full-Text Articles in Environmental Microbiology and Microbial Ecology
Bacterioplankton Growth Responses To Temperature And Chlorophyll Variations In Estuaries Measured By Thymidine:Leucine Incorporation Ratio, Fk Shiah, Hw Ducklow
Bacterioplankton Growth Responses To Temperature And Chlorophyll Variations In Estuaries Measured By Thymidine:Leucine Incorporation Ratio, Fk Shiah, Hw Ducklow
VIMS Articles
To identify the biochemical response of heterotrophic bacterioplankton to changing environmental conditions, seasonal and diel cycles of bacterial protein and DNA synthesis rates were estimated in temperate estuarine habitats from H-3-leucine (Leu) and H-3-thymidine (TdR) incorporation rates. Several short-term temperature manipulation experiments (5 to 35 degrees C) and 2 mesocosm experiments were performed to examine the effects of temperature and substrate supply on the ratio of Leu:TdR, respectively. The molar ratio of Leu to TdR varied about 5-fold (5.6 to 29.5) in the field and the values of the ratio were lower and more constant during high temperature (>25 …
Thermophilic Bacterial Activity In A Deep-Sea Sediment From The Pacific Ocean, Fred C. Dobbs, Karen A. Selph
Thermophilic Bacterial Activity In A Deep-Sea Sediment From The Pacific Ocean, Fred C. Dobbs, Karen A. Selph
OES Faculty Publications
Thermophilic bacterial activity was detected in a deep-sea sediment sample from the South Pacific Ocean at 12 degrees S, 135 degrees W, an area of the seafloor distant from known hydrothermal venting. Incubation of sediments amended with C-14-glutamate indicated maximal respiration (evolution of (CO2)-C-14) and assimilation (incorporation of C-14 into acid-precipitated macromolecules) of substrate at 52 degrees C, relative to 4 and 22 degrees C. A parallel experiment at another site (2 degrees S, 140 degrees W) yielded no evidence of thermophily. Thermophilic bacteria may be deposited in deep-sea sediments following their long-distance dispersal from hydrothermal vents (e.g. the East …
Increase In Fluorescence Intensity Of 16s Rrna In Situ Hybridization In Natural Samples Treated With Chloramphenicol, Cleber C. Ouverney, Jed A. Fuhrman
Increase In Fluorescence Intensity Of 16s Rrna In Situ Hybridization In Natural Samples Treated With Chloramphenicol, Cleber C. Ouverney, Jed A. Fuhrman
Faculty Publications, Biological Sciences
Despite the numerous advantages of fluorescent in situ hybridization for the identification of single prokaryotic cells with 16S rRNA probes, use of the technique with natural samples, especially those from the marine environment, is still problematic. The low percentage of fluorescently labeled cells constitutes the primary problem for in situ hybridization of natural samples, probably due to low cellular rRNA content. This study represents an attempt to improve detection of marine prokaryotes by increasing cellular rRNA content without changing the species composition. Cells from three California coastal sites were treated with chloramphenicol, an inhibitor of protein synthesis and rRNA degradation, …
Enumeration Of Enterococcus Sp. Using A Modified Me Method, Mw Rhodes, H Kator
Enumeration Of Enterococcus Sp. Using A Modified Me Method, Mw Rhodes, H Kator
VIMS Articles
A modified mE medium (mEI) containing the chromogenic substrate indoxyl-beta-D-glucoside to detect beta-D-glucosidase activity was evaluated with respect to specificity and recovery of enterococci from environmental eaters. Extending incubation from 24 to 48 h improved enterococci recovery but 77% of the colonies classified as non-target were confirmed as enterococci. Randomly chosen enterococcal isolates from sewage, exposed in microcosms containing 0.22 mu m membrane filtered fresh or estuarine water, exhibited differences in persistence as a function of exposure treatment. Decreasing the concentration of or eliminating indoxyl-beta-D-glucoside from mE did not significantly affect recovery of purified isolates.