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Metagenomic Analysis (metagenomic + analysis)
Selected AbstractsWidespread known and novel phosphonate utilization pathways in marine bacteria revealed by functional screening and metagenomic analysesENVIRONMENTAL MICROBIOLOGY, Issue 1 2010Asuncion Martinez Summary Phosphonates (Pn), compounds with a direct C,P bond instead of the more common C,O,P ester bond, constitute a significant fraction of marine dissolved organic phosphorus and recent evidence suggests that they may be an alternative source of P for marine microorganisms. To further characterize the microorganisms and pathways involved in Pn utilization, we screened bacterioplankton genomic libraries for their ability to complement an Escherichia coli strain unable to use Pns as a P source. Using this approach we identified a phosphonatase pathway as well as a novel pair of genes that allowed utilization of 2-aminoethylphosphonate (2-AEPn) as the sole P source. These pathways are present in diverse bacteria common in marine plankton including representatives of Proteobacteria, Planctomycetes and Cyanobacteria. Analysis of metagenomic databases for Pn utilization genes revealed that they are widespread and abundant among marine bacteria, suggesting that Pn metabolism is likely to play an important role in P-depleted surface waters, as well as in the more P-rich deep-water column. [source] To what extent did Neanderthals and modern humans interact?BIOLOGICAL REVIEWS, Issue 2 2009Kristian J. Herrera ABSTRACT Neanderthals represent an extinct hominid lineage that existed in Europe and Asia for nearly 400,000 years. They thrived in these regions for much of this time, but declined in numbers and went extinct around 30,000 years ago. Interestingly, their disappearance occurred subsequent to the arrival of modern humans into these areas, which has prompted some to argue that Neanderthals were displaced by better suited and more adaptable modern humans. Still others have postulated that Neanderthals were assimilated into the gene pool of modern humans by admixture. Until relatively recently, conclusions about the relationships between Neanderthals and contemporary humans were based solely upon evidence left behind in the fossil and archaeological records. However, in the last decade, we have witnessed the introduction of metagenomic analyses, which have provided novel tools with which to study the levels of genetic interactions between this fascinating Homo lineage and modern humans. Were Neanderthals replaced by contemporary humans through dramatic extinction resulting from competition and/or hostility or through admixture? Were Neanderthals and modern humans two independent, genetically unique species or were they a single species, capable of producing fertile offspring? Here, we review the current anthropological, archaeological and genetic data, which shed some light on these questions and provide insight into the exact nature of the relationships between these two groups of humans. [source] A metagenomic analysis of soil bacteria extends the diversity of quorum-quenching lactonasesENVIRONMENTAL MICROBIOLOGY, Issue 3 2008Kashif Riaz Summary A metagenomic library of 10 121 clones, generated from bacteria inhabiting a pasture soil from France, was screened for the presence of fosmids conferring either N -acylhomoserine lactone (NAHL) synthesis or NAHL degradation ability upon their Escherichia coli host. No clone producing NAHLs was identified whereas one, containing a 31 972 bp insert in fosmid p2H8, allowed NAHL degradation. This led to the cloning and identification of a gene, qlcA, encoding an NAHL-lactonase activity, as judged by lactone-ring closure and HPLC/MS analyses of NAHL degradation products. The qlcA gene efficiently quenched quorum-sensing regulated pathogenic functions when expressed in Pectobacterium carotovorum. The QlcA peptide belongs to the family of zinc-dependent metallohydrolases and appears to be distantly related to other NAHL-lactonases discovered in Agrobacterium, Bacillus, Photorhabdus and Rhizobium. In-silico analysis of the metagenomic insert revealed the occurrence of 20 orf, with a constant GC% and codon usage, suggesting a unique bacterial origin. Nine out of these 20 orf were homologous to genes encoding biosynthesis of arginine; they were clustered with an unusual succession argFJADBCRGH. The fosmid p2H8 is able to complement the argA, argB and argC mutants in E. coli. Phylogenetic analysis showed that 9 orf out of 20 were related to sequences from members of the Acidobacteria, supporting the hypothesis that the analysed insert might be originated from an organism related to this phylum. [source] Evaluating high-throughput sequencing as a method for metagenomic analysis of nematode diversityMOLECULAR ECOLOGY RESOURCES, Issue 6 2009DOROTA L. PORAZINSKA Abstract Nematodes play an important role in ecosystem processes, yet the relevance of nematode species diversity to ecology is unknown. Because nematode identification of all individuals at the species level using standard techniques is difficult and time-consuming, nematode communities are not resolved down to the species level, leaving ecological analysis ambiguous. We assessed the suitability of massively parallel sequencing for analysis of nematode diversity from metagenomic samples. We set up four artificial metagenomic samples involving 41 diverse reference nematodes in known abundances. Two samples came from pooling polymerase chain reaction products amplified from single nematode species. Two additional metagenomic samples consisted of amplified products of DNA extracted from pooled nematode species. Amplified products involved two rapidly evolving ~400-bp sections coding for the small and large subunit of rRNA. The total number of reads ranged from 4159 to 14771 per metagenomic sample. Of these, 82% were > 199 bp in length. Among the reads > 199 bp, 86% matched the referenced species with less than three nucleotide differences from a reference sequence. Although neither rDNA section recovered all nematode species, the use of both loci improved the detection level of nematode species from 90 to 97%. Overall, results support the suitability of massively parallel sequencing for identification of nematodes. In contrast, the frequency of reads representing individual species did not correlate with the number of individuals in the metagenomic samples, suggesting that further methodological work is necessary before it will be justified for inferring the relative abundances of species within a nematode community. [source] Next-generation sequencing and metagenomic analysis: a universal diagnostic tool in plant virologyMOLECULAR PLANT PATHOLOGY, Issue 4 2009IAN P. ADAMS SUMMARY A novel, unbiased approach to plant viral disease diagnosis has been developed which requires no a priori knowledge of the host or pathogen. Next-generation sequencing coupled with metagenomic analysis was used to produce large quantities of cDNA sequence in a model system of tomato infected with Pepino mosaic virus. The method was then applied to a sample of Gomphrena globosa infected with an unknown pathogen originally isolated from the flowering plant Liatris spicata. This plant was found to contain a new cucumovirus, for which we suggest the name ,Gayfeather mild mottle virus'. In both cases, the full viral genome was sequenced. This method expedites the entire process of novel virus discovery, identification, viral genome sequencing and, subsequently, the development of more routine assays for new viral pathogens. [source] Hidden pathogens uncovered: metagenomic analysis of urinary tract infectionsANDROLOGIA, Issue 2 2008C. Imirzalioglu Summary Urinary tract infections (UTIs) are the most common kidney and urologic diseases in industrial nations and are usually caused through faecal contamination of the urinary tract. In this study, we have examined 1449 urine specimens both by culture and by PCR. The majority of UTIs examined were caused by Escherichia coli (35.15%), followed by miscellaneous bacteria (23.03%), and by Enterococcus faecalis (19.39%). A large fraction of fastidious and anaerobic bacteria (22.43%) was not detected under culture conditions but only by using PCR. This group of bacteria evade the standard culture conditions used in routine diagnostic laboratories examining urine specimens. The molecular approach used broad-range 16S rDNA PCR, denaturing high-performance liquid chromatography analysis, sequencing, and bioinformatic analysis to uncover these ,hidden' pathogens and is recommended in particular when examining leukocyte esterase-positive and culture-negative urinary tract specimens. [source] | ||||||||||