Brack Christiane, Mikolasch Annett, Schauer Frieder
Department of Applied Microbiology, Institute of Microbiology, University Greifswald, Friedrich-Ludwig-Jahn-Str. 15, 17487, Greifswald, Germany,
Mar Biotechnol (NY). 2014 Aug;16(4):385-95. doi: 10.1007/s10126-014-9559-y. Epub 2014 Jan 22.
We report the detection by gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry analyses of the secreted 2,5-diketopiperazines (DKPs) cyclo(-Ala-Pro), cyclo(-Gly-Pro), cyclo(-Val-Pro), cyclo(-Ile-Pro), cyclo(-Leu-Pro), cyclo(-Pro-Pro), cyclo(-HyP-Pro), cyclo(-Met-Pro), and cyclo(-Phe-Pro) produced by Bacillus pumilus. The study focuses on a marine isolate and a laboratory test strain of B. pumilus with capabilities to lyse pregrown living cell lawns of different bacterial species, among them Arthrobacter citreus. Chromatographic methods were used to analyze induced bioactive compounds. At least 13 different DKPs are produced by B. pumilus. Both strains respond with an increased production of the DKPs cyclo(-Gly-Pro), cyclo(-Ala-Pro), and cyclo(-Val-Pro) to the presence of pasteurized A. citreus cells after 4 h in a nutrient-poor liquid medium. In agar diffusion assays, these DKPs did not cause lysis zones in living cell lawns, but they did inhibit further growth of several pregrown test bacteria in microplates even at concentrations as low as 1 μg ml(-1). Antibiotic substances produced by B. pumilus after 20 h of cultivation in a special lysis medium showed lytic activity in cell-free extracts of B. pumilus culture supernatants.
我们报告了通过气相色谱/质谱分析和液相色谱/质谱分析检测到短小芽孢杆菌分泌的2,5-二酮哌嗪（DKP）环（-丙氨酸-脯氨酸）、环（-甘氨酸-脯氨酸）、环（-缬氨酸-脯氨酸）、环（-异亮氨酸-脯氨酸）、环（-亮氨酸-脯氨酸）、环（-脯氨酸-脯氨酸）、环（-羟脯氨酸-脯氨酸）、环（-甲硫氨酸-脯氨酸）和环（-苯丙氨酸-脯氨酸）。该研究聚焦于一株海洋分离株和一株短小芽孢杆菌实验室测试菌株，它们能够裂解不同细菌物种（包括柠檬节杆菌）预先培养的活细胞菌苔。采用色谱方法分析诱导产生的生物活性化合物。短小芽孢杆菌至少产生13种不同的DKP。在营养贫乏的液体培养基中培养4小时后，两株菌株对经巴氏杀菌的柠檬节杆菌细胞的存在都有反应，环（-甘氨酸-脯氨酸）、环（-丙氨酸-脯氨酸）和环（-缬氨酸-脯氨酸）的产量增加。在琼脂扩散试验中，这些DKP在活细胞菌苔中未引起裂解区，但即使在低至1μg ml(-1)的浓度下，它们也能抑制微孔板中几种预先培养的测试细菌的进一步生长。在特殊裂解培养基中培养20小时后，短小芽孢杆菌产生的抗生素物质在短小芽孢杆菌培养上清液的无细胞提取物中表现出裂解活性。
