Diversity of Halophilic Gram-positive Bacteria Isolated from Coastal and Estuarine Environments

Autor: Yu-Shan Cheng, 鄭伃珊
Rok vydání: 2003
Druh dokumentu: 學位論文 ; thesis
Popis: 91
Halophilic Gram-negative bacteria are widely found in coastal zones and marine areas. They are also commonly present in the brackish water environments of estuary. In contrast, halophilic Gram-positive bacteria are rare in the microbial communities of estuary, coast and sea. Our laboratory had totally isolated 113 strains of halophilic or halotolerant bacteria, preliminarily identified as Gram-positive bacteria, from the sediment under mangroves at Tan-shui River estuary and Gau-Mei Taichung, and marine water at the coastal sites of Taiwan (Er-jen River estuary etc.) as well as Ba-dou-Zi Keelung and Shen-Ao. The propose of this study was to screen halophilic bacteria from the isolated strains and analyzed these bacteria for their diverse genera and species. There only 41 strains of 113 isolates were halophilic gram positive bacteria. According to Na+ requirement, endospore production, cell morphology, glucose fermentation and colony morphology, 41 strains were divided into 11 groups: the strains of group 1-8 required Na+ for growth, the strains of group 9-11 were not ; and only the strains of group 6 and 9 were facultatively anaerobes which were able to ferment glucose, the strains of other 9 groups were aerobe which were unable to ferment glucose. Group 1 contained two strains, which were the only group producing endospores. The cells of this bacterial group were regular rods and grew into orange circular colonies. Group 2 only included one strain, which could not ferment glucose and was characterized by its orange circular colonies and regular rod cells like group 1. However, the production of endospore was not observed in group 2, a distinction between group 1 and group 2. Group 3 only included one strain, which grew into pink circular colonies and utilized glucose as sole carbone source for growth, a distinction between group 3 and group 1-2. Group 4 contained 4 strains and group 5 contained 15 strains, which could not ferment glucose and the cells of this group were regular rod like group 1-3. However, the production of irregular gray colonies and white circular colonies separatly, a distinction between group 4-5 and group 1-3. Group 6 only included one strain, which were the only group grew into colorless circular colonies, ferment glucose and the cells of this group were irregular rods, a distinction between group 6 and group 1-5. Group 7 contained 2 strains, which the cells of this group were irregular rods, and the strain could not growthed in complex-medium whithout ultra Mg2+, a distinction between group 7 and other 10 groups. Group 8 only included one strain, which the cells of this group were irregular rods, and the only group grew into yellow colonies. Group 9 contained two strains, which the cells of this group were irregular rods, grew into white circular colonies and could not ferment glucose. Group 10 only included one strain, which were the only group grew into red circular colonies, and the cells of this group were regular rods. Group 11 contained 11 strains, which the cells of this group were regular rods,and grew into irregular gray colonies beside I strain grew into white circular colonies. The level of 16S rDNA sequence similarity revealed that the strains C1055 and J169 of Group 1 could be considered as Bacillus hwajinpoensis.The strain CS13 of Group 2 could be considered as Halobacillus trueperi. The strain B8 of Group 3, M336 of Group 7, A53 of Group 9 and A57 of Group 6 could be considered to represent a new species. The strains J149 and BS13 of Group 4, J607 and J717 of Group 5, and A2 of Group 11 Stappia aggregata the closest similary The strains A51 of Group 10 and Ba1a8 of Group 8 was identical to Rhodovulum sulfidophilum and Microbacterium ketoreductum, the closest similary. Based on the phylogenetic tree rebuilt by the 16S rDNA sequence analysis, it was revealed that the 11 groups contained at least 8 species in 8 genera. It is valuable to mention a strain in group 7, M336. Unlike other strains, it could grow neither in complex medium without added Mg2+, nor in 100％ marine water or 5% NaCl solution. In addition, it was only 94.6％ identical to 16S rDNA sequence of Devosia neptuniae, the closest similary. Therefore, there was no doubt M336 might be a new species or even a new genus. In this study, the selected strain in group 3, 4, 5, 6, 7, 9, 10 and 11 displaying Gram-positive was revealed that their closest species were all Gram-negative via 16S rDNA sequence analysis. A further study should be required to clarify why the outcome contradictory to common observation could occur.
Databáze: Networked Digital Library of Theses & Dissertations
Externí odkaz: