{"id":142212,"date":"2013-01-21T13:33:06","date_gmt":"2013-01-21T12:33:06","guid":{"rendered":"http:\/\/www.madrimasd.org\/blogs\/universo\/?p=142212"},"modified":"2013-01-21T13:33:06","modified_gmt":"2013-01-21T12:33:06","slug":"bacterias-en-suelos-deserticos-un-potencial-inmenso-para-la-obtencion-de-compuestos-de-utilidad","status":"publish","type":"post","link":"https:\/\/www.madrimasd.org\/blogs\/universo\/2013\/01\/21\/142212","title":{"rendered":"Bacterias en suelos des\u00e9rticos: Un potencial inmenso para la obtenci\u00f3n de compuestos de utilidad"},"content":{"rendered":"

Ya os hemos comentado en m\u00e1s de una ocasi\u00f3n que aplicar el concepto biol\u00f3gico de especie<\/span><\/a> resulta altamente problem\u00e1tico en el mundo de los procariotas<\/span><\/a>, debido al alto flujo horizontal de genes entre individuos filogen\u00e9ticamente muy dispares, al menos en apariencia. El medio ed\u00e1fico alberga una inmensa cantidad de microrganismos incluso en los ambientes denominados extrem\u00f3filos, como lo son los desiertos<\/strong><\/span>. Sin embargo, el aislamiento y cultivo de muchos tipos de bater\u00edas en los laboratorios tan solo alcanza su \u00e9xito en pocos casos, lo que impide estimar la diversidad microbiana de los suelos<\/span><\/a>. En este sentido, las t\u00e9cnicas moleculares, al analizar la variedad de secuencias gen\u00f3micas y\/o sus metabolitos, pueden permitir que nos aproximemos a entender la diversidad funcional (que no taxon\u00f3mica) de las comunidades<\/strong><\/span>. Ahora bien, m\u00e1s que de diversidad, deber\u00edamos apelar al concepto de variabilidad<\/strong><\/span>,\u00a0como hacen los autores de la nota de prensa que analizamos hoy, al que a\u00f1aden\u00a0un calificativo adicional\u00a0(en este caso metagen\u00f3mica). Pues bien, los investigadores aludidos, partiendo de estos conocimientos sobradamente reconocidos por los expertos, llevaron a cabo un estudio conforme a los siguientes pasos secuencialmente<\/strong>: (i)<\/strong><\/span> elecci\u00f3n de tres tipos de suelos geogr\u00e1ficamente distantes en ambientes des\u00e9rticos; (ii) <\/strong><\/span>recolecci\u00f3n de muestras y an\u00e1lisis de las mismas mediante t\u00e9cnicas moleculares, con vistas a analizar tal diversidad\/variabilidad metagen\u00f3mica; y (iii) <\/strong><\/span>comparaci\u00f3n de la semejanza\/distancia de los materiales org\u00e1nicos aludidos entre las muestras. Sus resultados no hacen m\u00e1s que corroborar\u00a0ideas previamente expuestas, es decir (i)<\/strong> <\/span>en los desiertos existe una gran abundancia y variedad de \u201ctipos bacterianos\u201d (hecho ya conocido); (ii) <\/strong><\/span>que tales datos son indicadores de una diversidad\/variabilidad mucho mayor que la obtenida por los cl\u00e1sicos cultivos en laboratorio y (iii)<\/strong><\/span> que como corolario de todo ello es muy probable que puedan obtenerse en el futuro una gran cantidad de compuestos de inter\u00e9s industrial<\/strong><\/span>, como anticancer\u00edgenos, etc. En otras palabras, que la bioprospecci\u00f3n de suelos<\/span><\/a> resulta ser un \u00e1mbito al que deber\u00edamos prestar mucha m\u00e1s atenci\u00f3n. Pues bien, todo ello resulta tan trivial como obvio<\/strong><\/span>. \u00bfQu\u00e9 novedad aporta tal investigaci\u00f3n?.<\/p>\n

\"desiertos-suelos-microorganismos-univ-davis\"<\/span><\/p>\n

Los desiertos albergan una gran variedad de microrganismos. Fuente Universidad de Davis<\/span><\/a> <\/span>Francamente creo que casi ninguna, descontando posibles mejoras en las t\u00e9cnicas moleculares de reconocimiento de los compuestos existentes en el suelo (DNA, prote\u00ednas, etc.). La \u00fanica nota de inter\u00e9s que se puede observar reside en que los tres suelos eran des\u00e9rticos<\/strong><\/span>, a pesar de lo cual la variedad de segmentos gen\u00f3micos y metabolitos distintos entre ellos eran muy\u00a0 acusados. A falta de leer el art\u00edculo original (ver resumen al final del post), en el material que exponemos abajo,<\/span> no se indica si realmente los suelos pertenec\u00edan al mismo grupo taxon\u00f3mico, o a varios distintos, lo cual tambi\u00e9n resulta ser un dato de sumo inter\u00e9s a la hora de<\/strong><\/span> dilucidar si las diferencias detectadas sobrepasaban sus expectativas (\u00bfcu\u00e1les?) o no. Resumiendo nada nuevo que no trat\u00e1ramos en diversos post previos de nuestra bit\u00e1cora<\/strong><\/span>. \u00bfNovedad? \u00a1Pues va a ser que no!. M\u00e1s bien una estrategia para publicar \u201cpapers<\/em>\u201dque no aportan nada o casi nada<\/strong><\/span>. Eso s\u00ed, al meno se publicita la importancia de la investigaci\u00f3n b\u00e1sica y aplicada en la bioprospecci\u00f3n de suelos<\/span><\/a>.<\/p>\n

Juan Jos\u00e9 Ib\u00e1\u00f1ez <\/strong><\/span><\/p>\n

Genes Culled from Desert Soils Suggest Potential Medical Resource<\/span><\/a><\/strong><\/h3>\n

ScienceDaily (May 27, 2012)<\/em><\/span><\/strong> \u2014 Despite their ecologic similarity, soils from three geographically distinct areas of the American southwest harbor vastly different collections of small, biosynthetic genes, a finding that suggests the existence of a far greater diversity of potentially useful products than was previously supposed<\/strong>. The research is published in the May issue of Applied and Environmental Microbiology<\/em>.<\/p>\n

Natural compounds have been the sources of the majority of new drugs <\/strong>approved by the US Food and Drug Administration, and bacteria have been the biggest single source of these therapeutically relevant compounds. Most bacterially-derived antibiotic and anticancer agents were discovered by culturing bacteria from environmental samples<\/strong>, and then examining the metabolites they produce in laboratory fermentation studies. But the vast majority of bacterial species cannot be cultured, which suggested that the world might be awash in potentially useful, but unknown bacterial metabolites<\/strong>.<\/p>\n

In this study, Sean Brady of the Howard Hughes Medical Institute, Rockefeller University, New York, NY, and colleagues extracted DNA from soils from the Sonoran Desert of Arizona, the Anza Borrego section of the Sonoran Desert of California, and the Great Basin Desert of Utah<\/strong>. They used this DNA to construct very large metagenomic DNA libraries<\/strong>, and screened these libraries for three of the most common classes of small molecule biosynthesis systems, type I modular polyketides, type II iterative polyketides, and non-ribosomal peptides, says Brady.<\/p>\n

The investigators used PCR to<\/strong> amplify collections of gene fragments from each of the three libraries and compared these to assess the similarities and differences between the collections of genes cloned from each environment, says Brady.<\/p>\n

\u00abOur work suggests that the genomes of environmental bacteria could encode many additional drug-like molecules, including compounds that might serve, among other things, as new antibiotics and anticancer agents,\u00bb<\/strong> says Brady. \u00abThis is a small preliminary study that warrants additional investigations of more environments and more extensive sequence analysis, but it suggests that environmental bacteria have the potential to encode a large additional treasure trove of new medicines<\/strong>.\u00bb<\/p>\n

Story Source: <\/strong>The above story is reprinted<\/a> from materials provided by American Society for Microbiology<\/strong><\/a>. Note: Materials may be edited for content and length. For further information, please contact the source cited above.<\/em><\/p>\n

Journal Reference<\/strong><\/span>: B. V. B. Reddy, D. Kallifidas, J. H. Kim, Z. Charlop-Powers, Z. Feng, S. F. Brady.Natural Product Biosynthetic Gene Diversity in Geographically Distinct Soil Microbiomes<\/strong>.Applied and Environmental Microbiology<\/em>, 2012; 78 (10): 3744 DOI: 10.1128\/AEM.00102-12<\/a><\/p>\n

Resumen del trabajo Original<\/strong><\/span><\/p>\n

<\/strong>Appl Environ Microbiol.<\/a> 2012 May;78(10):3744-52. Epub 2012 Mar 16.<\/p>\n

Natural product biosynthetic gene diversity in geographically distinct soil microbiomes.<\/strong><\/span><\/p>\n

Reddy BV<\/a>, Kallifidas D<\/a>, Kim JH<\/a>, Charlop-Powers Z<\/a>, Feng Z<\/a>, Brady SF<\/a>.<\/p>\n

Source<\/strong><\/span><\/p>\n

Laboratory of Genetically Encoded Small Molecules, Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA.<\/p>\n

Abstract<\/strong><\/span><\/p>\n

The number of bacterial species estimated to exist on Earth has increased dramatically in recent years. This newly recognized species diversity has raised the possibility that bacterial natural product biosynthetic diversity has also been significantly underestimated by previous culture-based studies<\/strong>. Here, we compare 454-pyrosequenced nonribosomal peptide adenylation domain, type I polyketide ketosynthase domain, and type II polyketide ketosynthase alpha gene fragments amplified from cosmid libraries constructed using DNA isolated from three different arid soils<\/strong>. While 16S rRNA gene sequence analysis indicates these cloned metagenomes contain DNA from similar distributions of major bacterial phyla, we found that they contain almost completely distinct collections of secondary metabolite biosynthetic gene sequences<\/strong>. When grouped at 85% identity<\/strong>, only 1.5% of the adenylation domain, 1.2% of the ketosynthase, and 9.3% of the ketosynthase alpha sequence clusters contained sequences from all three metagenomes<\/strong>. Although there is unlikely to be a simple correlation between biosynthetic gene sequence diversity and the diversity of metabolites encoded by the gene clusters in which<\/strong> these genes reside, our analysis further suggests that sequences in one soil metagenome are so distantly related to sequences in another metagenome that they are, in many cases, likely to arise from functionally distinct gene clusters. The marked differences observed among collections of biosynthetic genes found in even ecologically similar environments suggest that prokaryotic natural product biosynthesis diversity is, like bacterial species diversity, potentially much larger than appreciated from culture-based studies<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Ya os hemos comentado en m\u00e1s de una ocasi\u00f3n que aplicar el concepto biol\u00f3gico de especie resulta altamente problem\u00e1tico en el mundo de los procariotas, debido al alto flujo horizontal de genes entre individuos filogen\u00e9ticamente muy dispares, al menos en apariencia. El medio ed\u00e1fico alberga una inmensa cantidad de microrganismos incluso en los ambientes denominados extrem\u00f3filos, como lo son los desiertos. Sin embargo, el aislamiento y cultivo de muchos tipos de bater\u00edas en los laboratorios tan solo alcanza su \u00e9xito en pocos casos, lo que impide estimar la diversidad microbiana de los suelos. En este sentido, las t\u00e9cnicas moleculares, al\u2026<\/p>\n","protected":false},"author":26,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0},"categories":[596,592,615],"tags":[17972,46726,17970,46910,47283],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":4}},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/142212"}],"collection":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/users\/26"}],"replies":[{"embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/comments?post=142212"}],"version-history":[{"count":10,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/142212\/revisions"}],"predecessor-version":[{"id":143695,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/142212\/revisions\/143695"}],"wp:attachment":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/media?parent=142212"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/categories?post=142212"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/tags?post=142212"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}