Department of Biology & CESAM, University of Aveiro, Aveiro, Portugal.
FEMS Microbiol Ecol. 2013 Jun;84(3):451-60. doi: 10.1111/1574-6941.12075. Epub 2013 Feb 7.
Many members of the genus Psychrobacter are endemic in extremely cold and saline environments and the genus has been described as only marginally successful in warmer habitats. In a previous study the Psychrobacter genus was, unexpectedly, the most frequently isolated bacterial genus from the sea-surface microlayer (SML) and the underlying water (UW) of a temperate estuary (Ria de Aveiro, Portugal). Here we analysed the diversity in Psychrobacter populations inhabiting this estuary. Samples were collected at three dates and three locations from sea-SML and UW. Isolated Psychrobacter strains were well-adapted to temperatures and salt concentrations above the ones described as optimal for most members of this genus. Hydrocarbon-degrading potential was not confirmed for these strains. We developed and optimized a reliable and specific denaturing gradient gel electrophoresis (DGGE)-based method for the analysis of Psychrobacter populations in aquatic systems. DGGE profiles inferred that Psychrobacter populations were very stable in the estuary, a strong indication for the presence of well-adapted phylotypes. The analysis of genus-specific clone libraries revealed a surprisingly high diversity among Psychrobacter in Ria de Aveiro. Results indicated that novel species were probably cultivated. Significant differences between sea-SML and UW Psychrobacter communities were revealed. Observed diversity trends may be related to environmental factors such as salinity and/or anthropogenic pressures such as contamination with hydrocarbons.
许多极端寒冷和高盐环境中特有的假单胞菌属成员，并且该属仅在温暖的生境中被描述为略有成功。在之前的一项研究中，假单胞菌属出乎意料地成为了从温带河口的海面微层（SML）和下面的水（UW）中最常分离到的细菌属。在这里，我们分析了栖息在这个河口的假单胞菌种群的多样性。从三个日期和三个地点从海-SML 和 UW 采集了样品。分离出的假单胞菌菌株能够很好地适应温度和盐浓度，超过了该属大多数成员描述的最佳条件。这些菌株不具备降解碳氢化合物的潜力。我们开发并优化了一种可靠且特定的变性梯度凝胶电泳（DGGE）方法，用于分析水生系统中的假单胞菌种群。DGGE 图谱推断，假单胞菌种群在河口非常稳定，这强烈表明存在适应性良好的生物型。属特异性克隆文库的分析揭示了在奥维拉河口假单胞菌中令人惊讶的高多样性。结果表明，可能培养了新的物种。海-SML 和 UW 假单胞菌群落之间存在显著差异。观察到的多样性趋势可能与环境因素有关，例如盐度和/或人为压力，例如碳氢化合物污染。
