The Peptide Transporter 1(PepT1)plays an important role in animal protein nutrition.This is a lowaffinity/high-capacity,stereoselective transmembrane transporter that mediates the uptake of a fraction of dietary amino...The Peptide Transporter 1(PepT1)plays an important role in animal protein nutrition.This is a lowaffinity/high-capacity,stereoselective transmembrane transporter that mediates the uptake of a fraction of dietary amino acids in their di-and tripeptide forms.PepT1 is highly expressed in the intestines of vertebrates and the current studies examining PepT1 function have concentrated mostly on mammals and less emphasis has been placed on protein nutrition in fish.In the gastrointestinal track,amino acids are absorbed more efficiently in the form of small peptides than as free amino acids suggesting a potential role of PepT1 in the optimization of amino acid absorption which is relevant for fish nutrition.Therefore,this review focused on the physiological characteristics,structures,tissue distribution and expression of PepT1 transcripts and regulation of PepT1 protein in fish.展开更多
Biological denitrification is a crucial process in the nitrogen biogeochemical cycle,and Thermus has been reported to be a significant heterotrophic denitrifier in terrestrial geothermal environments.However,neither t...Biological denitrification is a crucial process in the nitrogen biogeochemical cycle,and Thermus has been reported to be a significant heterotrophic denitrifier in terrestrial geothermal environments.However,neither the denitrification potential nor the evolutionary history of denitrification genes in the genus Thermus or phylum Deinococcota is well understood.Here,we performed a comparative analysis of 23 Thermus genomes and identified denitrification genes in 15 Thermus strains.We confirmed that Thermus harbors an incomplete denitrification pathway as none of the strains contain the nosZ gene.Ancestral character state reconstructions and phylogenetic analyses showed that narG,nirS,and norB genes were acquired by the last common ancestor of Thermales and were inherited vertically.In contrast,nirK of Thermales was acquired via two distinct horizontal gene transfers from Proteobacteria to the genus Caldithermus and from an unknown donor to the common ancestor of all known Thermus species except Thermus filiformis.This study expands our understanding of the genomic potential for incomplete denitrification in Thermus,revealing a largely vertical evolutionary history of the denitrification pathway in the Thermaceae,and supporting the important role for Thermus as an important heterotrophic denitrifier in geothermal environments.展开更多
基金This study was supported by Natural Science Foundation of China(31402311,31372545)Program for Innovative Research Team(in Science and Technology)in University of Henan Province(14IRTSTHN013).
文摘The Peptide Transporter 1(PepT1)plays an important role in animal protein nutrition.This is a lowaffinity/high-capacity,stereoselective transmembrane transporter that mediates the uptake of a fraction of dietary amino acids in their di-and tripeptide forms.PepT1 is highly expressed in the intestines of vertebrates and the current studies examining PepT1 function have concentrated mostly on mammals and less emphasis has been placed on protein nutrition in fish.In the gastrointestinal track,amino acids are absorbed more efficiently in the form of small peptides than as free amino acids suggesting a potential role of PepT1 in the optimization of amino acid absorption which is relevant for fish nutrition.Therefore,this review focused on the physiological characteristics,structures,tissue distribution and expression of PepT1 transcripts and regulation of PepT1 protein in fish.
基金supported by funding from the National Natural Science Foundation of China(Nos.91951205,92051108,31850410475,and 31970122)the National Science and Technology Fundamental Resources Investigation Program of China(2021FY100900)the U.S.National Science Foundation(DEB 1557042 and DEB 1841658).
文摘Biological denitrification is a crucial process in the nitrogen biogeochemical cycle,and Thermus has been reported to be a significant heterotrophic denitrifier in terrestrial geothermal environments.However,neither the denitrification potential nor the evolutionary history of denitrification genes in the genus Thermus or phylum Deinococcota is well understood.Here,we performed a comparative analysis of 23 Thermus genomes and identified denitrification genes in 15 Thermus strains.We confirmed that Thermus harbors an incomplete denitrification pathway as none of the strains contain the nosZ gene.Ancestral character state reconstructions and phylogenetic analyses showed that narG,nirS,and norB genes were acquired by the last common ancestor of Thermales and were inherited vertically.In contrast,nirK of Thermales was acquired via two distinct horizontal gene transfers from Proteobacteria to the genus Caldithermus and from an unknown donor to the common ancestor of all known Thermus species except Thermus filiformis.This study expands our understanding of the genomic potential for incomplete denitrification in Thermus,revealing a largely vertical evolutionary history of the denitrification pathway in the Thermaceae,and supporting the important role for Thermus as an important heterotrophic denitrifier in geothermal environments.
