Topic
Bacteria
About: Bacteria is a research topic. Over the lifetime, 23676 publications have been published within this topic receiving 715990 citations. The topic is also known as: eubacteria.
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TL;DR: The competition between polyphosphate accumulating bacteria (PP bacteria) and another group of microorganisms (tentatively named “G bacteria”) has been observed in laboratory sequencing batch reactors exhibiting enhanced biological phosphate removal (EBPR).
294 citations
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TL;DR: Generic tests have been performed to check the viability of Escherichia coli bacteria in silica gels and it is found that more bacteria remain culturable in the gel than in an aqueous suspension.
Abstract: The encapsulation of enzymes within silica gels has been extensively studied during the past decade for the design of biosensors and bioreactors. Yeast spores and bacteria have also been recently immobilized within silica gels where they retain their enzymatic activity, but the problem of the long-term viability of whole cells in an inorganic matrix has never been fully addressed. It is a real challenge for the development of sol-gel processes. Generic tests have been performed to check the viability of Escherichia coli bacteria in silica gels. Surprisingly, more bacteria remain culturable in the gel than in an aqueous suspension. The metabolic activity of the bacteria towards glycolysis decreases slowly, but half of the bacteria are still viable after one month. When confined within a mineral environment, bacteria do not form colonies. The exchange of chemical signals between isolated bacteria rather than aggregates can then be studied, a point that could be very important for 'quorum sensing'.
294 citations
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TL;DR: A very simple and rapid method for extracting genomic DNA from Gram-negative bacteria, Gram-positive bacteria and yeasts is presented and the supernatant contains DNA suitable for molecular analyses, such as PCR, restriction enzyme digestion and genomic library construction.
Abstract: A very simple and rapid method for extracting genomic DNA from Gram-negative bacteria, Gram-positive bacteria and yeasts is presented. In this method, bacteria or yeasts are lysed directly by phenol and the supernatant is extracted with chloroform to remove traces of phenol. The supernatant contains DNA that is suitable for molecular analyses, such as PCR, restriction enzyme digestion and genomic library construction. This method is reproducible and simple for the routine DNA extraction from bacteria and yeasts.
294 citations
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TL;DR: D.L. COUTEAU, A.R. GIBSON, G. WILLIAMSON and C.B. FAULDS.
Abstract: hydroxycinnamic acids, in the human large intestine. Methods and Results: Thirty-five isolates recovered after anaerobic batch culture incubation of human faecal bacteria in a chlorogenic acid-based medium were screened for cinnamoyl esterase activity. Six isolates released the hydroxycinnamate, ferulic acid, from its ethyl ester in a plate-screening assay, and these were identified through genotypic characterization (16S rRNA sequencing) as Escherichia coli (three isolates), Bifidobacterium lactis and Lactobacillus gasseri (two strains). Chlorogenic acid hydrolysing activities were essentially intracellular. These cinnamoyl esterase-producing organisms were devoid of other phenolic-degrading activities. Conclusions: The results show that certain gut bacteria, including some already recognized as potentially health-promoting (i.e. species belonging to the genera Bifidobacterium and Lactobacillus), are involved in the release of bioactive hydroxycinnamic acids in the human colon. Significance and Impact of the Study: Free hydroxycinnamates, including caffeic, ferulic and p-coumaric acids, exhibit antioxidant and anticarcinogenic properties both in vitro and in animal models. Given that the gut flora has a major role in human nutrition and health, some of the beneficial effects of phenolic acids may be ascribed to the microflora involved in metabolism.
294 citations
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TL;DR: Molecular data will be shown for genes of Alcaligenes eutrophus, purple non-sulfur bacteria, Such as Rhodospirillum rubrum, purple sulfur bacteria, such as Chromatium vinosum, pseudomonads belonging to rRNA homology group I, and for the Gram-positive bacterium Rhodococcus ruber.
Abstract: The current knowledge on the structure and on the organization of polyhydroxyalkanoic acid (PHA)-biosynthetic genes from a wide range of different bacteria, which rely on different pathways for biosynthesis of this storage polyesters, is provided. Molecular data will be shown for genes of Alcaligenes eutrophus, purple non-sulfur bacteria, such as Rhodospirillum rubrum, purple sulfur bacteria, such as Chromatium vinosum, pseudomonads belonging to rRNA homology group I, such as Pseudomonas aeruginosa, Methylobacterium extorquens, and for the Gram-positive bacterium Rhodococcus ruber. Three different types of PHA synthases can be distinguished with respect to their substrate specificity and structure. Strategies for the cloning of PHA synthase structural genes will be outlined which are based on the knowledge of conserved regions of PHA synthase structural genes and of the PHA-biosynthetic routes in bacteria as well as on the heterologous expression of these genes and on the availability of mutants impaired in the accumulation of PHA. In addition, a terminology for the designation of PHAs and of proteins and genes relevant for the metabolism of PHA is suggested.
293 citations