Research progress on the mechanism of low temperature adaptation and antifreeze protein of fish
Temperature is crucial for regulating the biological function of fish.Fish living in extremely cold environment for a long time can survive due to adaptive evolution.The production of antifreeze protein is one of the most important adaptive characteristics.Different fish have different abilities to adapt to environmental temperature.Under low temperature stress,the fish's neuroendocrine system regulates its physiological activities by releasing hormones,and the sugar metabolism,fatty acid metabolism and protein metabolism have undergone momentous changes.The extremely cold-water environment can not only affect the gene expression and hormone secretion of fish,but also affect the metabolism process of the body as a whole.The low-temperature adaptation mechanism of fish is reviewed from the aspects of physiological adaptation and evolutionary adaptation of fish.Among them,antifreeze protein and antifreeze glycoprotein inhibit the growth of ice crystals in plasma by covering the ice surface that can contact water,thus reducing the freezing point of plasma.Increasing the proportion of unsaturated fatty acids in the cell membrane to increase the fluidity of the cell membrane can also maintain the physiological activity of cells under low temperature and enhance the adaptability of fish to low temperature.In addition,in the process of long-term adaptation of fish to the environment,the construction of many fish genomes and low-temperature tolerance transcriptome has led to the discovery of many key pathways and major genes related to low-temperature tolerance,and the continuous evolution of the genome,through the acquisition,deletion and large-scale expansion of functional genes to adapt to long-term low-temperature environment.Long-term low-temperature stress makes fish adapt at the epigenetic level.Domestic and foreign scholars have found that antifreeze proteins have essential functions,enabling organisms to survive in cold environment,and widely exist in various cold-resistant species.In this paper,the research progress in the origin and structure of antifreeze protein,functional characteristics,cloning and functional identification of antifreeze protein-related genes are described in details.It is found that changing the expression mode of genes can adjust the cold-adapted fish to better adapt to cold environment.To excavate antifreeze protein-related genes,many scholars use cloning,transgenic and other technologies to obtain corresponding genes and perform functional identification.The status of relevant research shows that the metabolic pathway and molecular signal pathway of fish under low temperature stress can be studied by genomics,and the mechanism of low temperature adaptation can be analyzed at biological level as a whole.Using this method,a variety of low temperature tolerance functional genes have been excavated,and in non-histological studies,many genes have also been revealed to be related to cold tolerance of fish,such as SCD1,Elovl,Hsp70 and Hsp90(heat shock protein).Due to the high species diversity of fish,the genetic background and distribution area of various fish are different,and the degree of low temperature tolerance is different,which makes the mechanism of low temperature tolerance of fish still unclear.In recent years,the research on fish antifreeze protein has focused on the antifreeze mechanism and genetic engineering of fish antifreeze protein,while the research on the gene related to antifreeze protein and the molecular mechanism of fish low-temperature adaptation is still relatively scarce.At present,the research and development of the molecular mechanism of low temperature adaptability of fish has attracted increasing attention.The huge fish population makes the ability of low temperature tolerance of different species of fish different,and a lot of basic research work is needed to excavate more fish low temperature tolerance genes and study its mechanism of action.
low temperature adaptabilityantifreeze proteinclonefunctional identificationfish
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维普
