好客嗜酸两面菌W1寡营养酸性热泉环境的适应机制

Adaptation of Acidianus hospitalis W1 to oligotrophic and acidic hot spring environments

摘要:

摘要:【目的】从基因组水平揭示好客嗜酸两面菌(Acidianus hospitalis) W1对寡营养酸性热泉环境的适应机制。【方法】使用NCBI非冗余蛋白数据库、Uniport蛋白数据库以及Sulfolobus数据库对好客嗜酸两面菌W1基因组序列进行功能注释，使用KEGG数据库对基因组进行In slico代谢途径重构，在此基础之上，采用比较基因组学方法对代谢途径进行鉴定和完善。【结果】好客嗜酸两面菌W1 具备多样化的代谢方式以适应寡营养酸性热泉环境。W1菌株通过3-羟基丙酸/4-羟基丁酸和乙二酸-4-羟基丁酸循环进行CO2 固定、通过氧化还原型无机硫化物(Reduced inorganic sulfur compounds，RISCs)获取能量营自养型生长。但W1菌株与模式菌株Acidianus ambivalens的硫代谢方式不同，W1基因组中缺少编码亚硫酸-受体氧化还原酶(SAOR)、腺苷硫酸(APS)还原酶、硫酸腺苷酰转移酶(SAT)和腺苷硫酸:磷酸腺苷转移酶(APAT)的基因。此外，W1菌株可以通过非磷酸化的分支的ED途径和TCA循环进行葡萄糖代谢，糖类和氨基酸转运蛋白以及相应水解酶的存在表明W1能够利用部分有机物营兼性自养型生长。与A.ambivalens不同，W1菌株不能利用H2作为电子供体。【结论】多样化的代谢方式为好客嗜酸两面菌W1更好地适应寡营养酸性热泉环境提供了重要保障，对于W1菌株特有代谢方式的揭示也丰富了对于嗜酸两面菌(Acidianus)属物种代谢多样性的认知。

Abstract:

Abstract:［Objective］To study the adaptation of A．hospitalis W1 to oligotrophic and acidic hot spring environments at the whole genome level．［Methods］We annotated the gene functions and constructed metabolic pathways of strain W1 by using different databases，such as NCBI non-redundant database (NRDB)，UniProt，Sulfolobus protein database and Kyoto Encyclopedia of Genes and Genomes (KEGG)．The metabolic pathways were polished according to the results of comparative genomics．［Results］ Strain W1 grew autotrophically by fixing CO2 as carbon source through 3-hydroxypropionate/4-hydroxybutyrate or dicarboxylate-4-hydroxybutyrate cycle，and gained energy for growth by oxidation of reduced inorganic sulfur compounds (RISCs)．Strain W1 differenced from A．ambivalens because its genome did not possess sulfur-metabolizing genes encoding sulfite: acceptor oxidoreductase，adenosine phosphosulfate reductase，sulfate adenylyl transferase and phosphoadenosine phosphosulfate reductase．Glucose was metabolized by strain W1 through nonphosphorylated Entner-Doudoroff pathway and tricarboxylic acid cycle．In addition，the sugar and amino acids transporters，as well as related hydrolysis enzymes were identified in the genome．These results suggest that strain W1 could also grow facultative autotrophically．Strain W1 cannot use H2 as electron donor due to lack of hydrogenase encoding genes．［Conclusion］The versatile metabolic patterns afforded A．hospitalis W1 the ability to adapt to oligotrophic and acidic hot spring environments．Furthermore，the unique metabolic features of strain W1 will help to better understand the metabolic diversities of Acidianus.