{"title":"海洋好氧菌的碘酸盐还原作用","authors":"Ken Kine, Shigeki Yamamura, Seigo Amachi","doi":"10.3389/fmicb.2024.1446596","DOIUrl":null,"url":null,"abstract":"Iodate reductase (Idr) gene cluster (<jats:italic>idrABP<jats:sub>1</jats:sub>P<jats:sub>2</jats:sub></jats:italic>) is involved in bacterial iodate (IO<jats:sub>3</jats:sub><jats:sup>−</jats:sup>) respiration under anaerobic conditions. Putative <jats:italic>idr</jats:italic> gene clusters are present in both anaerobic and aerobic bacteria; however, the specific physiological roles of <jats:italic>idr</jats:italic> genes in aerobic bacteria remain unclear. Therefore, in this study, three marine aerobic bacteria with putative <jats:italic>idr</jats:italic> gene clusters (<jats:italic>Roseovarius azorensis</jats:italic>, <jats:italic>Notoacmeibacter marinus</jats:italic>, and <jats:italic>Aliiroseovarius sediminilitoris</jats:italic>) were grown in the presence of iodate to determine whether they can reduce iodate to iodide (I<jats:sup>−</jats:sup>). All tested bacteria almost completely reduced 2 mM iodate under static conditions but only reduced 0.1–0.5 mM iodate under shaking conditions. Moreover, the washed cell suspension of <jats:italic>R. azorensis</jats:italic> reduced iodate only when the cells were pre-grown statically in the presence of iodate. Transcriptional analysis revealed that the expression levels of <jats:italic>idrA</jats:italic>, <jats:italic>idrB</jats:italic>, <jats:italic>idrP<jats:sub>1</jats:sub></jats:italic>, and <jats:italic>idrP<jats:sub>2</jats:sub></jats:italic> genes were upregulated in <jats:italic>R. azorensis</jats:italic> when the cells were grown statically in the presence of iodate. Specifically, <jats:italic>idrA</jats:italic> expression was induced by 0.1 μM iodate and was up to 14-fold higher compared to that of the non-iodate control. These results suggest that marine aerobic bacteria reduce iodate under oxygen-limited conditions, and that this capacity is induced by environmentally relevant levels of iodate in seawater. Our results suggest that marine aerobic bacteria contribute to iodide production in marine surface waters, thereby affecting the global iodine cycling and ozone budget.","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":null,"pages":null},"PeriodicalIF":4.0000,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Iodate reduction by marine aerobic bacteria\",\"authors\":\"Ken Kine, Shigeki Yamamura, Seigo Amachi\",\"doi\":\"10.3389/fmicb.2024.1446596\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Iodate reductase (Idr) gene cluster (<jats:italic>idrABP<jats:sub>1</jats:sub>P<jats:sub>2</jats:sub></jats:italic>) is involved in bacterial iodate (IO<jats:sub>3</jats:sub><jats:sup>−</jats:sup>) respiration under anaerobic conditions. Putative <jats:italic>idr</jats:italic> gene clusters are present in both anaerobic and aerobic bacteria; however, the specific physiological roles of <jats:italic>idr</jats:italic> genes in aerobic bacteria remain unclear. Therefore, in this study, three marine aerobic bacteria with putative <jats:italic>idr</jats:italic> gene clusters (<jats:italic>Roseovarius azorensis</jats:italic>, <jats:italic>Notoacmeibacter marinus</jats:italic>, and <jats:italic>Aliiroseovarius sediminilitoris</jats:italic>) were grown in the presence of iodate to determine whether they can reduce iodate to iodide (I<jats:sup>−</jats:sup>). All tested bacteria almost completely reduced 2 mM iodate under static conditions but only reduced 0.1–0.5 mM iodate under shaking conditions. Moreover, the washed cell suspension of <jats:italic>R. azorensis</jats:italic> reduced iodate only when the cells were pre-grown statically in the presence of iodate. Transcriptional analysis revealed that the expression levels of <jats:italic>idrA</jats:italic>, <jats:italic>idrB</jats:italic>, <jats:italic>idrP<jats:sub>1</jats:sub></jats:italic>, and <jats:italic>idrP<jats:sub>2</jats:sub></jats:italic> genes were upregulated in <jats:italic>R. azorensis</jats:italic> when the cells were grown statically in the presence of iodate. Specifically, <jats:italic>idrA</jats:italic> expression was induced by 0.1 μM iodate and was up to 14-fold higher compared to that of the non-iodate control. These results suggest that marine aerobic bacteria reduce iodate under oxygen-limited conditions, and that this capacity is induced by environmentally relevant levels of iodate in seawater. Our results suggest that marine aerobic bacteria contribute to iodide production in marine surface waters, thereby affecting the global iodine cycling and ozone budget.\",\"PeriodicalId\":12466,\"journal\":{\"name\":\"Frontiers in Microbiology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":4.0000,\"publicationDate\":\"2024-09-18\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Frontiers in Microbiology\",\"FirstCategoryId\":\"99\",\"ListUrlMain\":\"https://doi.org/10.3389/fmicb.2024.1446596\",\"RegionNum\":2,\"RegionCategory\":\"生物学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MICROBIOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers in Microbiology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.3389/fmicb.2024.1446596","RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MICROBIOLOGY","Score":null,"Total":0}
Iodate reductase (Idr) gene cluster (idrABP1P2) is involved in bacterial iodate (IO3−) respiration under anaerobic conditions. Putative idr gene clusters are present in both anaerobic and aerobic bacteria; however, the specific physiological roles of idr genes in aerobic bacteria remain unclear. Therefore, in this study, three marine aerobic bacteria with putative idr gene clusters (Roseovarius azorensis, Notoacmeibacter marinus, and Aliiroseovarius sediminilitoris) were grown in the presence of iodate to determine whether they can reduce iodate to iodide (I−). All tested bacteria almost completely reduced 2 mM iodate under static conditions but only reduced 0.1–0.5 mM iodate under shaking conditions. Moreover, the washed cell suspension of R. azorensis reduced iodate only when the cells were pre-grown statically in the presence of iodate. Transcriptional analysis revealed that the expression levels of idrA, idrB, idrP1, and idrP2 genes were upregulated in R. azorensis when the cells were grown statically in the presence of iodate. Specifically, idrA expression was induced by 0.1 μM iodate and was up to 14-fold higher compared to that of the non-iodate control. These results suggest that marine aerobic bacteria reduce iodate under oxygen-limited conditions, and that this capacity is induced by environmentally relevant levels of iodate in seawater. Our results suggest that marine aerobic bacteria contribute to iodide production in marine surface waters, thereby affecting the global iodine cycling and ozone budget.
期刊介绍:
Frontiers in Microbiology is a leading journal in its field, publishing rigorously peer-reviewed research across the entire spectrum of microbiology. Field Chief Editor Martin G. Klotz at Washington State University is supported by an outstanding Editorial Board of international researchers. This multidisciplinary open-access journal is at the forefront of disseminating and communicating scientific knowledge and impactful discoveries to researchers, academics, clinicians and the public worldwide.