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 detection and isolation of lactic acid bacteria by enrichment methods from wine grapes cultivated in vineyards located in New South Wales, Australia is studied.
Abstract: Aims: The detection and isolation of lactic acid bacteria by enrichment methods from wine grapes cultivated in vineyards located in New South Wales, Australia.
Methods and Results: Enrichment cultures in de Man, Rogosa and Sharpe (MRS) broth, MRS + ethanol (5%), MRS broth supplemented with 15% (v/v) tomato juice (MRST), pH 5·5 and 3·5 and autoenrichment in grape juice homogenate were used to detect lactic acid bacteria on wine grapes. Bacteria were isolated from enrichment cultures by plating onto MRS and MRST agar and identified by 16S rDNA sequence analysis and phenotypical methods. A molecular method, PCR-denaturing gradient gel electrophoresis (DGGE) was also used to examine the bacteria that developed in enrichment cultures. Species of Lactobacillus, Enterococcus, Lactococcus and Weissella were detected in enrichments by plating and PCR-DGGE. Other bacteria (Sporolactobacillus, Asaia, Bacillus ssp.) were also found in some enrichment cultures. The principal malolactic bacterium, Oenococcus oeni, was not isolated.
Conclusions: The incidence and populations of lactic acid bacteria on wine grapes were very low. Damaged grape berries showed a greater presence of these bacteria than undamaged berries. The diversity of bacterial species isolated from the grapes was greater than those previously reported and represented both lactic acid bacteria and nonlactic acid bacteria. Some of these bacteria (i.e. Lactobacillus lindneri, Lactobacillus kunkeei) could be detrimental to wine production. Oenococcus oeni was not found on grapes, but its recovery could be obscured by overgrowth from other species.
Significance and Impact of the Study: Lactic acid bacteria are significant in wine production because they conduct the malolactic fermentation and cause stuck or sluggish alcoholic fermentation and wine spoilage. This study investigates wine grapes as a potential source of these bacteria.
152 citations
TL;DR: The stationary-phase adaptation of E. coli has only recently begun to be investigated at the molecular level and a state of increased resistance against various stresses is established.
152 citations
TL;DR: The study found that five- and six-antibiotic-resistant bacteria were widely distributed in four types of enterobacteria from the secondary effluent, which could pose a serious problem as a secondary pollutant of drinking water.
152 citations
TL;DR: Archaea methanogens were the largest H2-utilizing populations in all animals, and a correlation was observed between the numbers of methanogen and those of cellulolytic microorganisms.
Abstract: Total number of bacteria, cellulolytic bacteria, and H2-utilizing microbial populations (methanogenic archaea, acetogenic and sulfate-reducing bacteria) were enumerated in fresh rumen samples from sheep, cattle, buffaloes, deer, llamas, and caecal samples from horses. Methanogens and sulfate reducers were found in all samples, whereas acetogens were not detected in some samples of each animal. Archaea methanogens were the largest H2-utilizing populations in all animals, and a correlation was observed between the numbers of methanogens and those of cellulolytic microorganisms. Higher counts of acetogens were found in horses and llamas (1 × 104 and 4 × 104 cells ml−1 respectively).
151 citations