Shindoh Suzune, Obayashi Yumiko, Suzuki Satoru
Center for Marine Environmental Studies, Ehime University.
Microbes Environ. 2021;36(1). doi: 10.1264/jsme2.ME20150.
Bacterial extracellular aminopeptidases are key enzymes in protein processing in oligotrophic seawater. To the best of our knowledge, the regulation of aminopeptidase production in microbes inhabiting seawater has not yet been reported. The present study attempted to experimentally clarify which organic materials affect bacterial extracellular aminopeptidase production by nutrient-rich and starved cells growing in artificial seawater using Photobacterium, Alteromonas, Ruegeria, and Sulfitobacter. In all four species, we found that peptides induced bacterial extracellular aminopeptidase production. Amino acids led to cell growth with markedly lower aminopeptidase production by Photobacterium and Sulfitobacter, but not by Alteromonas and Ruegeria. These results suggest that the extracellular aminopeptidases of marine bacteria are primarily produced on demand in response to the presence of relevant substrates (peptides) in seawater. Peptidyl substances may be regulatory nutrients for marine bacterial growth in aquatic environments.
细菌胞外氨肽酶是贫营养海水中蛋白质加工的关键酶。据我们所知，尚未有关于栖息在海水中的微生物氨肽酶产生调控的报道。本研究试图通过使用发光杆菌属、交替单胞菌属、鲁杰氏菌属和硫杆菌属，在人工海水中培养营养丰富和饥饿的细胞，通过实验阐明哪些有机物质会影响细菌胞外氨肽酶的产生。在所有这四个物种中，我们发现肽诱导细菌胞外氨肽酶的产生。氨基酸导致发光杆菌属和硫杆菌属细胞生长，同时氨肽酶产生显著降低，但交替单胞菌属和鲁杰氏菌属并非如此。这些结果表明，海洋细菌的胞外氨肽酶主要是根据海水中相关底物（肽）的存在按需产生的。肽基物质可能是水生环境中海洋细菌生长的调节性营养物质。
