Gunasekera Thusitha S, Bowen Loryn L, Zhou Carol E, Howard-Byerly Susan C, Foley William S, Striebich Richard C, Dugan Larry C, Ruiz Oscar N
Environmental Microbiology Group, University of Dayton Research Institute, University of Dayton, Dayton, Ohio, USA.
Lawrence Livermore National Laboratory, Livermore, California, USA.
Appl Environ Microbiol. 2017 May 1;83(10). doi: 10.1128/AEM.03249-16. Print 2017 May 15.
can utilize hydrocarbons, but different strains have various degrees of adaptation despite their highly conserved genome. ATCC 33988 is highly adapted to hydrocarbons, while strain PAO1, a human pathogen, is less adapted and degrades jet fuel at a lower rate than does ATCC 33988. We investigated fuel-specific transcriptomic differences between these strains in order to ascertain the underlying mechanisms utilized by the adapted strain to proliferate in fuel. During growth in fuel, the genes related to alkane degradation, heat shock response, membrane proteins, efflux pumps, and several novel genes were upregulated in ATCC 33988. Overexpression of genes in PAO1 provided some improvement in growth, but it was not as robust as that of ATCC 33988, suggesting the role of other genes in adaptation. Expression of the function unknown gene PA5359 from ATCC 33988 in PAO1 increased the growth in fuel. Bioinformatic analysis revealed that PA5359 is a predicted lipoprotein with a conserved Yx(FWY)xxD motif, which is shared among bacterial adhesins. Overexpression of the putative resistance-nodulation-division (RND) efflux pump PA3521 to PA3523 increased the growth of the ATCC 33988 strain, suggesting a possible role in fuel tolerance. Interestingly, the PAO1 strain cannot utilize -C and -C The expression of green fluorescent protein (GFP) under the control of promoters confirmed that gene promoter polymorphism affects the expression of genes. Promoter fusion assays further confirmed that the regulation of genes was different in the two strains. Protein sequence analysis showed low amino acid differences for many of the upregulated genes, further supporting transcriptional control as the main mechanism for enhanced adaptation. These results support that specific signal transduction, gene regulation, and coordination of multiple biological responses are required to improve the survival, growth, and metabolism of fuel in adapted strains. This study provides new insight into the mechanistic differences between strains and helpful information that may be applied in the improvement of bacterial strains for resistance to biotic and abiotic factors encountered during bioremediation and industrial biotechnological processes.
能够利用碳氢化合物，但是尽管不同菌株的基因组高度保守，它们的适应程度却各不相同。ATCC 33988对碳氢化合物具有高度适应性，而作为人类病原体的PAO1菌株适应性较差，降解喷气燃料的速率低于ATCC 33988。我们研究了这些菌株之间燃料特异性的转录组差异，以确定适应性菌株在燃料中增殖所利用的潜在机制。在燃料中生长期间，与烷烃降解、热休克反应、膜蛋白、外排泵以及几个新基因相关的基因在ATCC 33988中上调。PAO1中基因的过表达在一定程度上改善了生长，但不如ATCC 33988显著，这表明其他基因在适应过程中发挥了作用。将ATCC 33988中功能未知的基因PA5359在PAO1中表达，增加了其在燃料中的生长。生物信息学分析表明，PA5359是一种预测的脂蛋白，具有保守的Yx(FWY)xxD基序，该基序在细菌粘附素中共有。假定的耐药-固氮-分裂（RND）外排泵PA3521至PA3523的过表达增加了ATCC 33988菌株的生长，表明其在燃料耐受性中可能发挥作用。有趣的是，PAO1菌株不能利用-C和-C在启动子控制下绿色荧光蛋白（GFP）的表达证实了基因启动子多态性影响基因的表达。启动子融合试验进一步证实，两种菌株中基因的调控存在差异。蛋白质序列分析表明，许多上调基因的氨基酸差异较小，进一步支持转录控制是增强适应性的主要机制。这些结果支持，适应性菌株需要特定的信号转导、基因调控以及多种生物学反应的协调，以提高在燃料中的存活、生长和代谢能力。本研究为菌株之间的机制差异提供了新的见解，并提供了有用的信息，这些信息可应用于改良细菌菌株，以提高其在生物修复和工业生物技术过程中对生物和非生物因素的抗性。
