Du Hailian, Jiao Nianzhi, Hu Yaohua, Zeng Yonghui
State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China.
FEMS Microbiol Ecol. 2006 Jul;57(1):92-105. doi: 10.1111/j.1574-6941.2006.00090.x.
A systematic investigation of marine pigmented heterotrophic bacteria (PHB) based on the cultivation method and sequencing analysis of 16S rRNA genes was conducted in Chinese coastal and shelf waters and the Pacific Ocean. Both the abundance of PHB and the ratio of PHB to CFU decreased along trophic gradients from coastal to oceanic waters, with the highest values of 9.9 x 10(3) cell mL(-1) and 39.6%, respectively, in the Yangtze River Estuary. In contrast to the total heterotrophic bacteria (TB) and CFU, which were present in the whole water column, PHB were primarily confined to the euphotic zone, with the highest abundance of PHB and ratio of PHB to CFU occurring in surface water. In total, 247 pigmented isolates were obtained during this study, and the phylogenetic analysis showed a wide genetic diversity covering 25 genera of six phylogenetic classes: Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, Bacilli, Flavobacteria and Sphingobacteria. PHB belonging to Alphaproteobacteria, Flavobacteria and Sphingobacteria were obtained mainly from the South China Sea and East China Sea; PHB from the Pacific Ocean water were predominantly affiliated with Gammaproteobacteria, and most isolates from the Yangtze River Estuary fell into the classes Actinobacteria and Bacilli. The isolates exhibited various colours (e.g. golden, yellow, red, pink and orange), with genus or species specificity. Furthermore, the pigment of PHB cells absorbed light mainly in the wavelength range between 450 and 550 nm. In conclusion, our work has revealed that PHB with broad genetic diversity are widely distributed in the marine environment, and may account for up to 39.6% of culturable bacteria, equivalent to 1.4% of the total microbial community. This value might even be underestimated because it is probable that not all pigmented bacteria were isolated. Their abundance and genetic distribution are heavily influenced by environmental properties, such as light and nutrition, suggesting that they have important roles in the marine ecosystem, especially in the absorption of visible light.
基于培养方法和16S rRNA基因测序分析，对中国沿海和陆架水域以及太平洋中的海洋色素异养细菌（PHB）进行了系统调查。从沿海水域到大洋水域，随着营养梯度的变化，PHB的丰度以及PHB与菌落形成单位（CFU）的比值均呈下降趋势，在长江口分别达到最高值9.9×10³个细胞/毫升和39.6%。与存在于整个水柱中的总异养细菌（TB）和CFU不同，PHB主要局限于真光层，在表层水中PHB的丰度以及PHB与CFU的比值最高。在本研究中总共获得了247株色素分离株，系统发育分析显示其具有广泛的遗传多样性，涵盖六个系统发育类别的25个属：α-变形菌纲、γ-变形菌纲、放线菌纲、芽孢杆菌纲、黄杆菌纲和鞘脂杆菌纲。属于α-变形菌纲、黄杆菌纲和鞘脂杆菌纲的PHB主要从南海和东海获得；来自太平洋水域的PHB主要隶属于γ-变形菌纲，而长江口的大多数分离株属于放线菌纲和芽孢杆菌纲。这些分离株呈现出各种颜色（如金色、黄色、红色、粉色和橙色），具有属或种的特异性。此外，PHB细胞的色素主要在450至550纳米的波长范围内吸收光。总之，我们的研究表明，具有广泛遗传多样性的PHB广泛分布于海洋环境中，可能占可培养细菌的39.6%，相当于整个微生物群落的1.4%。由于可能并非所有色素细菌都被分离出来，这个值甚至可能被低估。它们的丰度和遗传分布受到光照和营养等环境特性的严重影响，这表明它们在海洋生态系统中，尤其是在吸收可见光方面具有重要作用。
