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Abstract：
Photobacterium spp. occur frequently in marine environments but have been recently also found as common spoilers on chilled meats. The environmental conditions in these ecological niches differ especially regarding salinity and ambient pressure. Linking the occurrence of photobacteria in different niches may elucidate its ecology and bring insights for the food industry. We investigated tolerance of Photobacterium (P.) phosphoreum and P. carnosum strains to high hydrostatic pressure and salinity and aligned our observations with presence of relevant genes. The strains were isolated from packaged meats and salmon (or the sea) to identify adaptations to marine and terrestrial habitats. Growth of all P. carnosum strains was reduced by 40 MPa hydrostatic pressure and >3% sodium chloride, suggesting loss of traits associated with marine habitats. In contrast, P. phosphoreum strains were only slightly affected, suggesting general adaptation to marine habitats. In accordance, these strains had gene clusters associated with marine niches, e.g. flagellar and lux-operons, being incomplete in P. carnosum. Occurrence of P. carnosum strains on packaged salmon and P. phosphoreum strains on meats therefore likely results from cross-contamination in meat and fish processing. Still, these strains showed intermediate traits regarding pressure- and halotolerance, suggesting developing adaptation to their respective environment.
摘要：
光细菌。在海洋环境中经常发生，但最近也被发现是冷藏肉类上的常见扰流板。这些生态位的环境条件各不相同，尤其是在盐度和环境压力方面。将不同生态位的光细菌的发生联系起来可能会阐明其生态学并为食品工业带来见识。我们调查了光细菌的耐受性(P.）磷酸和P.carnosum菌株具有高静水压力和盐度，并使我们的观察结果与相关基因的存在保持一致。从包装的肉类和鲑鱼（或海洋）中分离出菌株，以确定对海洋和陆地栖息地的适应性。40MPa静水压力和>3%氯化钠降低了所有肉芽肿菌株的生长，表明与海洋栖息地相关的性状丧失。相比之下,P.phosphoreum菌株仅受到轻微影响，表明对海洋栖息地的普遍适应。InAccording,这些菌株具有与海洋生态位相关的基因簇，例如鞭毛和勒克斯操纵子，在P.carnosum中不完整。因此，包装鲑鱼上的肉食假单胞菌菌株和肉类上的磷酸假单胞菌菌株的出现可能是由于肉类和鱼类加工中的交叉污染造成的。尽管如此，这些菌株表现出耐压性和耐盐性的中间特征，建议发展对各自环境的适应。
