Penetration of Oxygen into Bacterial Colonies

Wimpenny, J. W. T.; Coombs, Jana

doi:10.1099/00221287-129-4-1239

Cited by 45 publications

(38 citation statements)

References 2 publications

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“…For the purpose of this study it is assumed that the top layers of the biofilm are comparable to the steady state planktonic cells. It is known that the DO 2 profile within a biofilm varies with depth (deBeer and Stoodley, 1995;Revsbech, 1989;Wimpenny and Coombs, 1983) and the acid phosphatase specific activity is upregulated upon shift into anaerobiosis (Hallett et al, 1991). However, the phosphatase activity recorded in these cultures was the highest noted for this strain (c.f.…”

Section: Resultsmentioning

confidence: 95%

Phosphate release and heavy metal accumulation by biofilm-immobilized and chemically-coupled cells of acitrobacter sp. pre-grown in continuous culture

Finlay

Allan

Conner

et al. 1999

Biotechnol. Bioeng.

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Section: Resultsmentioning

confidence: 95%

Phosphate release and heavy metal accumulation by biofilm-immobilized and chemically-coupled cells of acitrobacter sp. pre-grown in continuous culture

Finlay

Allan

Conner

et al. 1999

Biotechnol. Bioeng.

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“…In addition, there is no information regarding the swarming ability of S. enterica serovar Typhimurium (a facultative anaerobe) under anaerobic conditions. In an aerobically grown colony, oxygen levels are drastically decreased towards the center and bottom (102). To see if a change in oxygen level or the creation of an oxygen gradient is required for swarming, we examined the efficiency of swarming in aerobic versus anaerobic environments.…”

Section: Resultsmentioning

confidence: 99%

Genetics of Swarming Motility inSalmonella entericaSerovar Typhimurium: Critical Role for Lipopolysaccharide

et al. 2000

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Salmonella enterica serovar Typhimurium can differentiate into hyperflagellated swarmer cells on agar of an appropriate consistency (0.5 to 0.8%), allowing efficient colonization of the growth surface. Flagella are essential for this form of motility. In order to identify genes involved in swarming, we carried out extensive transposon mutagenesis of serovar Typhimurium, screening for those that had functional flagella yet were unable to swarm. A majority of these mutants were defective in lipopolysaccharide (LPS) synthesis, a large number were defective in chemotaxis, and some had defects in putative two-component signaling components. While the latter two classes were defective in swarmer cell differentiation, representative LPS mutants were not and could be rescued for swarming by external addition of a biosurfactant. A mutation in waaG (LPS core modification) secreted copious amounts of slime and showed a precocious swarming phenotype. We suggest that the O antigen improves surface "wettability" required for swarm colony expansion, that the LPS core could play a role in slime generation, and that multiple two-component systems cooperate to promote swarmer cell differentiation. The failure to identify specific swarming signals such as amino acids, pH changes, oxygen, iron starvation, increased viscosity, flagellar rotation, or autoinducers leads us to consider a model in which the external slime is itself both the signal and the milieu for swarming motility. The model explains the cell density dependence of the swarming phenomenon.

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“…The relative proportions of unsaturated fatty acid markers, such as 16:17c, which is abundant in BcT FAME profiles (Table 3), is primarily affected by the concentration of the saturated fatty acid precursor (16:0) and oxygen availability (26). During growth on agar plates, the oxygen concentration may show spatial heterogeneities within BcT colonies that can affect the proportions of saturated and unsaturated fatty acid spore profiles compared to organisms grown in liquid media (26,58). Similarly, metabolic substrates can show heterogeneities within agar colonies (39).…”

Section: Discussionmentioning

confidence: 99%

Use of Fatty Acid Methyl Ester Profiles for Discrimination ofBacillus cereusT-Strain Spores Grown on Different Media

Ehrhardt

Chu

Brown

et al. 2010

Appl Environ Microbiol

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The goal of this study was to determine if cellular fatty acid methyl ester (FAME) profiling could be used to distinguish among spore samples from a single species (Bacillus cereus T strain) that were prepared on 10 different medium formulations. To analyze profile differences and identify FAME biomarkers diagnostic for the chemical constituents in each sporulation medium, a variety of statistical techniques were used, including nonmetric multidimensional scaling (nMDS), analysis of similarities (ANOSIM), and discriminant function analysis (DFA). The results showed that one FAME biomarker, oleic acid (18:1 9c), was exclusively associated with spores grown on Columbia agar supplemented with sheep blood and was indicative of blood supplements that were present in the sporulation medium. For spores grown in other formulations, multivariate comparisons across several FAME biomarkers were required to discern profile differences. Clustering patterns in nMDS plots and R values from ANOSIM revealed that dissimilarities among FAME profiles were most pronounced when spores grown with disparate sources of complex additives or protein supplements were compared (R > 0.8), although other factors also contributed to FAME differences. DFA indicated that differentiation could be maximized with a targeted subset of FAME variables, and the relative contributions of branched FAME biomarkers to group dissimilarities changed when different media were compared. When taken together, these analyses indicate that B. cereus spore samples grown in different media can be resolved with FAME profiling and that this may be a useful technique for providing intelligence about the production methods of Bacillus organisms in a forensic investigation.

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Penetration of Oxygen into Bacterial Colonies

Cited by 45 publications

References 2 publications

Phosphate release and heavy metal accumulation by biofilm-immobilized and chemically-coupled cells of acitrobacter sp. pre-grown in continuous culture

Phosphate release and heavy metal accumulation by biofilm-immobilized and chemically-coupled cells of acitrobacter sp. pre-grown in continuous culture

Genetics of Swarming Motility inSalmonella entericaSerovar Typhimurium: Critical Role for Lipopolysaccharide

Use of Fatty Acid Methyl Ester Profiles for Discrimination ofBacillus cereusT-Strain Spores Grown on Different Media

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