小菜蛾幼虫肠道细菌肉杆菌的代谢表型分析

Phenotypic fingerprints of the bacterium Carnobacterium maltaromaticum from the larval gut of the diamondback moth, Plutella xylostella(Lepidoptera: Plutellidae)

【目的】肠道细菌肉杆菌Carnobacterium maltaromaticum是小菜蛾Plutella xylostella幼虫肠道的可培养优势细菌,本研究旨在阐明肉杆菌的代谢表型特征。【方法】采用BIOLOG细胞表型芯片技术系统地研究了肉杆菌的细胞表型;采用PM1-PM10代谢板,对肉杆菌的950种代谢表型进行了测定。【结果】肉杆菌能代谢34.74%的碳源、99.47%的氮源、100%的硫源和79.66%的磷源;高效代谢的碳源为有机酸类和糖化合物类,高效代谢的氮源为氨基酸类和肽类。该肠道细菌未表现出生物合成途径。肉杆菌具有广泛的适应性,能在分别具有高达10%氯化钠、6%氯化钾、5%硫酸钠、20%乙二醇、6%甲酸钠、7%尿素、8%乳酸钠、200 mmol/L磷酸钠(p H 7.0)、200 mmol/L苯甲酸钠(p H 5.2)、100 mmol/L硫酸铵(p H 8.0)、100 mmol/L硝酸钠和100 mmol/L亚硝酸钠的渗透溶液中正常代谢,不能在9%-12%的乳酸钠渗透溶液中代谢;其适应p H值范围为5-10,最适约为10.0。在多种氨基酸的作用下,肉杆菌仅有脱氨酶活性,而无脱羧酶活性。【结论】肉杆菌的代谢特征增加了我们对该肠道细菌的认识,同时为其功能的研究和其与宿主小菜蛾的互作研究提供了信息基础。

[Objectives] To investigate the phenotypic characteristics of Carnobacterium maltaromaticum, one of the dominant cultivable bacterial species in the larval gut of the diamondback moth, Plutella xylostella. [Methods] The phenotype of C. maltaromaticum was analyzed with BIOLOG phenotype Micro Array（PM）. A total of 950 different metabolic phenotypes were tested using PM plates 1-10. [Results] C. maltaromaticum was able to metabolize 34.74% of the tested carbon sources, 99.47% of nitrogen sources, 100% of sulfur sources, and 79.66% of phosphorus sources. Most informative utilization patterns for carbon sources of C. maltaromaticum were organic acids and carbohydrates, and for nitrogen were various amino acids and peptides. The bacterium did not have different biosynthetic pathways but was highly adaptable and continued to metabolize in osmolytes with up to 10% sodium chloride, 6% potassium chloride, 5% sodium sulfate, 20% ethylene glycol, 6% sodium formate, 7% urea, 8% sodium lactate, 200 mmol/L sodium phosphate（p H 7.0）, 200 mmol/L sodium benzoate（p H 5.2）, 100 mmol/L ammonium sulfate（p H 8.0）, 100 mmol/L sodium nitrate, and 100 mmol/L sodium nitrite. It could not, however, grow in media with 9% to 12% sodium lactate. It had an active metabolism at p H values between 5 and 10, with an optimal p H of around 10.0. In the presence of various amino acids, C. maltaromaticum showed deaminase activity but no decarboxylase activity. [Conclusion] Phenotypic characterization of C. maltaromaticum has increased our knowledge of this bacterium and also revealed useful information on its function and the interaction between it and its host.