Font Size: a A A

Community Structure Analysis And Polyphasic Taxonomy Of Bacteria From Saline Environments

Posted on:2010-01-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y H WuFull Text:PDF
Abstract/Summary:PDF Full Text Request
Halophilic microorganisms are microbes inhabited in diverse saline environments. According to their adaptation to salt supplemented in media, these microbes are divided into halophilic and halotolerant groups. The halophilic microorganisms can grow up to the high salt concentrations, such as salt lakes, soda lakes, solar salterns, hypersaline soils, marine environments, etc, and they often have strong impact on the ecosystems in which the thrive. The property of microbial adaptation to high salt environments is mainly relation with enzymes and other bio-active substance. Much interest in halophilic adaptation has been supported by the search for life on the planets and the applications in biotechnology. So it is very significant not only in theory but also in practice to study halophiles.My research is based on our lab's work such as samples collection from high saline, microorganisms cultivation and related molecular technology. Ayakekumu Lake located in Xinjiang region, the estuary of the Yangtze River of the East China sea and the China nodule province in East Pacific ocean which were collected from three environment ecosystems were investigated. Cultivation-independent approaches based on rRNA cloning and sequencing were applied to survey microbial diversity in natural ecosystems. The identification and biodiversity of culturable microorganisms were performed by using the molecular technique subsequently. Based on the analysis of 16S rDNA gene sequence analysis and phenotype characteristics, the database of halophiles was established and enriched.In this study using molecular biology methods, construct 16S rDNA, nap A, nir S biomarker genes clone libraries at the estuary of the Yangtze River of the East China sea. Total 366 clones were analysis and 256 clones were sequenced and phylogenetic analysed. Bacteria biodiversity was very rich, mainly composed byγ-Proteobacteria,α-Proteobacteria, Acidobacteria,δ- Proteobacteria and Bacteroidetes. It indicate microbial community structure and their possible geochemical process.In accordance with the principle of polyphasic taxonomy, a systematic study had been conducted on the taxonomy of eight isolates. Six novel moderate halophilic bacteria species (Halomonas caseinilytica, Halomonas salifodinae, Marinobacter Pelagius, Pseudidiomarina maritima, Pseudidiomarina donghaiensis, Vibrio hangzhouensis ) as well as one halotorlerant halophilic bacteria species (Microbacterium profundi) and one halotorlerant halophilic bacteria genus (Croceicoccus gen. nov, Croceicoccus marinus) were proposed. This is the first study on the eight halophilic microbial species which was isolated from multiregions in China.
Keywords/Search Tags:halophilic microorganism, molecular ecology, microbial community structure, polyphasic taxonomy, novel species
PDF Full Text Request
Related items