Variation of specific proteins, mitochondria and fatty acid composition in gill of Scylla serrata (Crustacea, Decapoda) under low temperature adaptation

In the first part of this study, generation times relative to temperature, together with cardinal and conceptual temperatures, were determined for four strains of Xenorhabdus bacteria that represented three geographically distinct species. The data showed that the NF strain of Xenorhabdus bovienii, like the Umeå strain of the same species, is psychrotrophic, while Xenorhabdus sp. TX strain resembles Xenorhabdus nematophila All strain in being mesophilic. In the second part, the capacity of these bacteria to adapt to changes in temperature, shown by changes in fatty acid composition, was investigated. As temperature declined, the proportions of the two major unsaturated fatty acids, palmitoleic (16:1ω7) acid and oleic (18:1ω9) acid, increased significantly in all of the strains. The proportion of the prevalent saturated fatty acid, which was palmitic acid (16:0), decreased. In the All, NF, and Umeå strains, myristic acid (14:0), margaric acid (17:0), cyclopropane (17:0c), and arachidic acid (20:0) decreased with decreasing temperature. In the third part of the study, the synthesis of isozymes in response to changing temperature was investigated. For the seven enzymes studied, the numbers for which isozyme synthesis was temperature related were as follows: five for Umeå, four for All, three for NF, and two for TX. Where the study dealt with fatty acid composition and isozyme synthesis, the results show a broad capacity for physiological temperature adaptation among strains of different climatic origin.Key words: Xenorhabdus, temperature, psychrotroph, mesophile, fatty acid, isozyme.

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Effect of fabA and desA Mediated Low Temperature Adaption on Shewanella putrefaciens via Regulation of Unsaturated Fatty Acid Metabolism

Nanoscience and Nanotechnology Letters ◽

10.1166/nnl.2019.3023 ◽

2019 ◽

Vol 11 (10) ◽

pp. 1430-1437

Author(s):

Li Chen ◽

Shengping Yang ◽

Yunfang Qian ◽

Jing Xie

Keyword(s):

Fatty Acid Composition ◽

Fatty Acid ◽

Low Temperature ◽

Acid Composition ◽

Fatty Acid Metabolism ◽

Unsaturated Fatty Acid ◽

Acid Metabolism ◽

Shewanella Putrefaciens ◽

Spoilage Bacteria ◽

Temperature Environment

Shewanella putrefaciensis a kind of spoilage bacteria in low temperature chilled aquatic products, which seriously threats human health and aquaculture. The fatty acid composition of S. putrefaciens cell membranes has been shown to be involved in adaption of bacteria to various environments. However, the specific fatty acid metabolism of S. putrefaciens to the low temperature environment remains unknown. In this study, the growth of S. putrefaciens, the response of fatty acid composition to low temperature production, and the differential expression and synthesis of enzymes related to unsaturated fatty acid synthesis were investigated by lack of fabA and desA in S. putrefaciens. Results showed that loss of fabA and desA suppressed the growth of S. putrefaciens and reduced unsaturated fatty acid contents at low temperature. In addition, the upregulation of fabA, but not desA resulted in accumulation of unsaturated fatty acid. Up-regulations of fabA and desA both resulted in promotion of GPR41 and Retn gene and protein expressions. These results demonstrated that the deletions of fabA and desA resulted in reduction of unsaturated fatty acid and key downstream genes of fatty acid metabolism, which suggested that unsaturated fatty acid was involved in the adaptations of fabA and desA-mediated S. putrefaciens to the low temperature environment. These results provided a tentative mechanism of the synthesis of unsaturated fatty acids in S. putrefaciens under low temperature conditions.

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