<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Martiny, A. C.</style></author><author><style face="normal" font="default" size="100%">Kathuria, S.</style></author><author><style face="normal" font="default" size="100%">Berube, P. M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Widespread metabolic potential for nitrite and nitrate assimilation among Prochlorococcus ecotypes</style></title><secondary-title><style face="normal" font="default" size="100%">Proceedings of the National Academy of Sciences of the United States of America</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Proc. Natl. Acad. Sci. U. S. A.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">atlantic</style></keyword><keyword><style  face="normal" font="default" size="100%">community genomics</style></keyword><keyword><style  face="normal" font="default" size="100%">cyanobacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">metagenomics</style></keyword><keyword><style  face="normal" font="default" size="100%">narB</style></keyword><keyword><style  face="normal" font="default" size="100%">nirA</style></keyword><keyword><style  face="normal" font="default" size="100%">nitrogen</style></keyword><keyword><style  face="normal" font="default" size="100%">nitrogen cycle</style></keyword><keyword><style  face="normal" font="default" size="100%">ocean</style></keyword><keyword><style  face="normal" font="default" size="100%">phosphate acquisition genes</style></keyword><keyword><style  face="normal" font="default" size="100%">picophytoplankton</style></keyword><keyword><style  face="normal" font="default" size="100%">sea</style></keyword><keyword><style  face="normal" font="default" size="100%">synechococcus</style></keyword><keyword><style  face="normal" font="default" size="100%">tropical pacific</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">06/2009</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">pub/675</style></url></web-urls></urls><number><style face="normal" font="default" size="100%">26</style></number><volume><style face="normal" font="default" size="100%">106</style></volume><pages><style face="normal" font="default" size="100%">10787-10792</style></pages><isbn><style face="normal" font="default" size="100%">0027-8424</style></isbn><language><style face="normal" font="default" size="100%">English</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The marine cyanobacterium Prochlorococcus is the most abundant photosynthetic organism in oligotrophic regions of the oceans. The inability to assimilate nitrate is considered an important factor underlying the distribution of Prochlorococcus, and thought to explain, in part, low abundance of Prochlorococcus in coastal, temperate, and upwelling zones. Here, we describe the widespread occurrence of a genomic island containing nitrite and nitrate assimilation genes in uncultured Prochlorococcus cells from marine surface waters. These genes are characterized by low GC content, form a separate phylogenetic clade most closely related to marine Synechococcus, and are located in a different genomic region compared with an orthologous cluster found in marine Synechococcus strains. This sequence distinction suggests that these genes were not transferred recently from Synechococcus. We demonstrate that the nitrogen assimilation genes encode functional proteins and are expressed in the ocean. Also, we find that their relative occurrence is higher in the Caribbean Sea and Indian Ocean compared with the Sargasso Sea and Eastern Pacific Ocean, which may be related to the nitrogen availability in each region. Our data suggest that the ability to assimilate nitrite and nitrate is associated with microdiverse lineages within high- and low-light (LL) adapted Prochlorococcus ecotypes. It challenges 2 long-held assumptions that (i) Prochlorococcus cannot assimilate nitrate, and (ii) only LL adapted ecotypes can use nitrite. The potential for previously unrecognized productivity by Prochlorococcus in the presence of oxidized nitrogen species has implications for understanding the biogeography of Prochlorococcus and its role in the oceanic carbon and nitrogen cycles.&lt;/p&gt;</style></abstract><work-type><style face="normal" font="default" size="100%">Article</style></work-type><accession-num><style face="normal" font="default" size="100%">ISI:000267564300072</style></accession-num><notes><style face="normal" font="default" size="100%">&lt;p&gt;ISI Document Delivery No.: 465EITimes Cited: 6Cited Reference Count: 29Cited References:      BLANCHOT J, 1996, DEEP-SEA RES PT I, V43, P877     BOUMAN HA, 2006, SCIENCE, V312, P918, DOI 10.1126/science.1122692     BOYER TP, 2006, WORLD OCEAN DATABASE     CASEY JR, 2007, GEOPHYS RES LETT, V34, ARTN L10604     COLEMAN ML, 2006, SCIENCE, V311, P1768, DOI 10.1126/science.1122050     DELONG EE, 2005, NAT REV MICROBIOL, V3, P459, DOI 10.1038/nrmicro1158     DELONG EF, 2006, SCIENCE, V311, P496, DOI 10.1126/science.1120250     DUGDALE RC, 1967, LIMNOL OCEANOGR, V12, P196     DURAND MD, 2001, DEEP-SEA RES PT II, V48, P1983     FELSENSTEIN J, 2006, PHYLIP VERSION 3 66     FIELD CB, 1998, SCIENCE, V281, P237     FRIASLOPEZ J, 2008, P NATL ACAD SCI USA, V105, P3805, DOI     10.1073/pnas.0708897105     GALVAN A, 1996, J BIOL CHEM, V271, P2088     HERRERO A, 1985, FEMS MICROBIOL LETT, V26, P21     JENKINS BD, 2006, ENVIRON MICROBIOL, V8, P2083, DOI     10.1111/j.1462-2920.2006.01084.x     LIU H, 1998, DEEP-SEA RES PT II, V45, P2327     LUQUE I, 1992, MOL GEN GENET, V232, P7     MARTINY AC, 2006, P NATL ACAD SCI USA, V103, P12552, DOI     10.1073/pnas.0601301103     MARTINY AC, 2009, ENVIRON MICROBIOL, V11, P1340, DOI     10.1111/j.1462-2920.2009.01860.x     MARTINY AC, 2009, ENVIRON MICROBIOL, V11, P823, DOI     10.1111/j.1462-2920.2008.01803.x     MOORE JK, 2002, DEEP-SEA RES PT II, V49, P403     MOORE LR, 1998, NATURE, V393, P464     MOORE LR, 2002, LIMNOL OCEANOGR, V47, P989     PALENIK B, 2003, NATURE, V424, P1037, DOI 10.1038/nature01943     PARTENSKY F, 1996, DEEP-SEA RES PT I, V43, P1191     ROCAP G, 2003, NATURE, V424, P1042, DOI 10.1038/nature01947     RUBIO LM, 1998, J BACTERIOL, V180, P1200     RUSCH DB, 2007, PLOS BIOL, V5, P398, ARTN e77     VAULOT D, 1992, DEEP-SEA RES, V39, P727Martiny, Adam C. Kathuria, Satish Berube, Paul M.University of California, Irvine ; GBMFWe thank Antonia Herrero for assistance with the nitrate reductase assay; Penny Chisholm, Debbie Lindell, and Jennifer Martiny for many helpful comments on the manuscript; and the J. Craig Venter Institute (San Diego, CA) and Gordon and Betty Moore Foundation (GBMF, Palo Alto, CA) for allowing early access to the GOS samples from the Indian Ocean. RNA from the North Pacific Subtropical Gyre was provided by the DeLong and Chisholm laboratories at Massachusetts Institute of Technology. This work was supported in part by the University of California, Irvine; Paul Berube's contribution was supported by a grant from GBMF to S. Chisholm.Natl acad sciencesWashington&lt;/p&gt;</style></notes><auth-address><style face="normal" font="default" size="100%">&lt;p&gt;[Martiny, Adam C.; Kathuria, Satish] Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. [Martiny, Adam C.] Univ Calif Irvine, Dept Ecol &amp;amp; Evolutionary Biol, Irvine, CA 92697 USA. [Berube, Paul M.] MIT, Dept Civil &amp;amp; Environm Engn, Cambridge, MA 02139 USA.Martiny, AC, Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA.amartiny@uci.edu&lt;/p&gt;</style></auth-address></record></records></xml>