Riley Lee W
Full Text Available Abstract Background The genome of Mycobacterium tuberculosis harbors four copies of a cluster of genes termed mce operons. Despite extensive research that has demonstrated the importance of these operons on infection outcome, their physiological function remains obscure. Expanding databases of complete microbial genome sequences facilitate a comparative genomic approach that can provide valuable insight into the role of uncharacterized proteins. Results The M. tuberculosis mce loci each include two yrbE and six mce genes, which have homology to ABC transporter permeases and substrate-binding proteins, respectively. Operons with an identical structure were identified in all Mycobacterium species examined, as well as in five other Actinomycetales genera. Some of the Actinomycetales mce operons include an mkl gene, which encodes an ATPase resembling those of ABC uptake transporters. The phylogenetic profile of Mkl orthologs exactly matched that of the Mce and YrbE proteins. Through topology and motif analyses of YrbE homologs, we identified a region within the penultimate cytoplasmic loop that may serve as the site of interaction with the putative cognate Mkl ATPase. Homologs of the exported proteins encoded adjacent to the M. tuberculosis mce operons were detected in a conserved chromosomal location downstream of the majority of Actinomycetales operons. Operons containing linked mkl, yrbE and mce genes, resembling the classic organization of an ABC importer, were found to be common in Gram-negative bacteria and appear to be associated with changes in properties of the cell surface. Conclusion Evidence presented suggests that the mce operons of Actinomycetales species and related operons in Gram-negative bacteria encode a subfamily of ABC uptake transporters with a possible role in remodeling the cell envelope.
Jurado, Valme; Kroppenstedt, Reiner M; Saiz-Jimenez, Cesáreo; Klenk, Hans-Peter; Mouniée, Delphine; Laiz, Leonila; Couble, Andrée; Pötter, Gabriele; Boiron, Patrick; Rodríguez-Nava, Verónica
A novel actinomycete, strain OFN S31(T), was isolated from a complex biofilm in the Altamira Cave, Spain. A polyphasic study was carried out to clarify the taxonomic position of this strain. Phylogenetic analysis with 16S rRNA gene sequences of representatives of the genera Corynebacterium, Dietzia, Gordonia, Millisia, Mycobacterium, Nocardia, Rhodococcus, Segniliparus, Skermania, Tsukamurella and Williamsia indicated that strain OFN S31(T) formed a distinct taxon in the 16S rRNA gene tree that was more closely associated with the Mycobacterium clade. The type strain of Mycobacterium fallax was the closest relative of strain OFN S31(T) (95.6 % similarity). The cell wall contained meso-diaminopimelic acid, arabinose and galactose, which are characteristic components of cell-wall chemotype IV of actinomycetes. The sugars of the peptidoglycan were acetylated. The polar lipid pattern was composed of phosphatidylinositol, phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Strain OFN S31(T) is characterized by the absence of mycelium and mycolic acids. Strain OFN S31(T) had MK-8 as the major menaquinone. The DNA G+C content was 49.3 mol%, the lowest found among all taxa included in the suborder Corynebacterineae. Based on morphological, chemotaxonomic, phenotypic and genetic characteristics, strain OFN S31(T) is considered to represent a novel species of a new genus, for which the name Hoyosella altamirensis gen. nov., sp. nov. is proposed. The type strain of Hoyosella altamirensis is strain OFN S31(T) (=CIP 109864(T) =DSM 45258(T)). PMID:19643882
Mueller, Ulrich G; Ishak, Heather; Lee, Jung C; Sen, Ruchira; Gutell, Robin R
We reconstruct the phylogenetic relationships within the bacterial genus Pseudonocardia to evaluate two models explaining how and why Pseudonocardia bacteria colonize the microbial communities on the integument of fungus-gardening ant species (Attini, Formicidae). The traditional Coevolution-Codivergence model views the integument-colonizing Pseudonocardia as mutualistic microbes that are largely vertically transmitted between ant generations and that supply antibiotics that specifically suppress the garden pathogen Escovopsis. The more recent Acquisition model views Pseudonocardia as part of a larger integumental microbe community that frequently colonizes the ant integument from environmental sources (e.g., soil, plant material). Under this latter model, ant-associated Pseudonocardia may have diverse ecological roles on the ant integument (possibly ranging from pathogenic, to commensal, to mutualistic) and are not necessarily related to Escovopsis suppression. We test distinct predictions of these two models regarding the phylogenetic proximity of ant-associated and environmental Pseudonocardia. We amassed 16S-rRNA gene sequence information for 87 attine-associated and 238 environmental Pseudonocardia, aligned the sequences with the help of RNA secondary structure modeling, and reconstructed phylogenetic relationships using a maximum-likelihood approach. We present 16S-rRNA secondary structure models of representative Pseudonocardia species to improve sequence alignments and identify sequencing errors. Our phylogenetic analyses reveal close affinities and even identical sequence matches between environmental Pseudonocardia and ant-associated Pseudonocardia, as well as nesting of environmental Pseudonocardia in subgroups that were previously thought to be specialized to associate only with attine ants. The great majority of ant-associated Pseudonocardia are closely related to autotrophic Pseudonocardia and are placed in a large subgroup of Pseudonocardia that is known essentially only from cultured isolates (rather than cloned 16S sequences). The preponderance of the known ant-associated Pseudonocardia in this latter clade of culturable lineages may not necessarily reflect abundance of these Pseudonocardia types on the ants, but isolation biases when screening for Pseudonocardia (e.g., preferential isolation of autotrophic Pseudonocardia with minimum-nutrient media). The accumulated phylogenetic patterns and the possibility of isolation biases in previous work further erode support for the traditional Coevolution-Codivergence model and calls for continued revision of our understanding how and why Pseudonocardia colonize the microbial communities on the integument of fungus-gardening ant species. PMID:20333466
Corynebacterium pseudotuberculosis (Actinomycetales: Corynebacteriaceae) infection in horses causes external abscesses, infection of internal organs and ulcerative lymphangitis. The exact mechanism of infection remains unknown, but fly transmission is suspected. Scientists at Auburn University and U...
Full Text Available Actinomyces and Mycobacterium avium-intracellulare are facultative intracellular organisms, members of the bacterial order actinomycetales. Although Actinomyces can behave as copathogen when anatomic barriers are compromised, its coinfection with Mycobacterium avium-intracellulare has not previously been reported. We present the first reported case of palatal actinomycosis co-infection with disseminated MAC, in an HIV-infected subject with Kaposi sarcoma and diabetes. We discuss the pathogenesis of the complex condition of this subject.
Strobel, Tina; Schmidt, Yvonne; Linnenbrink, Anton; Luzhetskyy, Andriy; Luzhetska, Marta; Taguchi, Takaaki; Brötz, Elke; Paululat, Thomas; Stasevych, Maryna; Stanko, Oleg; Novikov, Volodymyr; Bechthold, Andreas
Saccharothrix espanaensis is a member of the order Actinomycetales. The genome of the strain has been sequenced recently, revealing 106 glycosyltransferase genes. In this paper, we report the detection of a glycosyltransferase from Saccharothrix espanaensis which is able to rhamnosylate different phenolic compounds targeting different positions of the molecules. The gene encoding the flexible glycosyltransferase is not located close to a natural product biosynthetic gene cluster. Therefore, t...
Full Text Available Abstract Background Lung transplant recipients have an increased risk for actinomycetales infection secondary to immunosuppressive regimen. Case presentation A case of pulmonary infection with bacteremia due to Tsukamurella tyrosinosolvens in a 54-year old man who underwent a double lung transplantation four years previously is presented. Conclusion The identification by conventional biochemical assays was unsuccessful and hsp gene sequencing was used to identify Tsukamurella tyrosinosolvens.
Singh, Ravindra Pal; Baghel, Ravi S.; Reddy, C. R. K.; Jha, Bhavanath
Epiphytic and endophytic bacteria associated with green macroalgae Ulva (U. fasciata and U. lactuca) and red macroalgae Gracilaria (G. corticata and G. dura) have been identified from three different seasons to evaluate the effect of quorum sensing (QS) molecules on carpospores liberation from Gracilaria dura. The bacterial isolates belonging to the orders Bacillales, Pseudomonadales, Alteromonadales, and Vibrionales were present in all seasons, whereas Actinomycetales and Enterobacteriales w...
Finster, Kai; Herbert, Rodney Andrew; Kjeldsen, Kasper Urup;
Two Gram-stain-positive, pigmented, non-motile, non-spore-forming, pleomorphic, rod-shaped bacteria (strains SV45T and SV47), isolated from a permafrost soil collected from the Adventdalen valley, Spitsbergen, northern Norway, have been characterized taxonomically using a polyphasic approach....... Phylogenetic analysis based on 16S rRNA gene sequences revealed that the two permafrost isolates formed a distinct phyletic line within the suborder Micrococcineae of the order Actinomycetales. DNA-DNA hybridization analyses indicate that strains SV45T and SV47 are closely related (60-69 % relatedness) and...
Sinha, Krishna Murari; Stephanou, Nicolas C.; Unciuleac, Mihaela-Carmen; Glickman, Michael S.; Shuman, Stewart
Mycobacterial UvrD2 is a DNA-dependent ATPase with 3′ to 5′ helicase activity. UvrD2 is an atypical helicase, insofar as its N-terminal ATPase domain resembles the superfamily I helicases UvrD/PcrA, yet it has a C-terminal HRDC domain, which is a feature of RecQ-type superfamily II helicases. The ATPase and HRDC domains are connected by a CxxC-(14)-CxxC tetracysteine module that defines a new clade of UvrD2-like bacterial helicases found only in Actinomycetales. By characterizing truncated ve...
Sachdeva, R.; Heidelberg, J.
Actinobacteria represent one of the largest and most diverse bacterial phyla and unlike most marine prokaryotes are gram-positive. This phylum encompasses a broad range of physiologies, morphologies, and metabolic properties with a broad array of lifestyles. The marine actinobacterial assemblage is dominated by the orders Actinomycetales and Acidimicrobiales (also known as the marine Actinobacteria clade). The Acidimicrobiales bacteria typically outnumber the Actinomycetales bacteria and are mostly represented by the OCS155 group. Although bacteria of the order Acidimicrobiales make up ~7.6% of the 16S matches from the Global Ocean Survey shotgun metagenomic libraries; very little is known about their potential function and role in biogeochemical cycling. Samples were collected from surface seawater samples in the Gulf of Maine (GOM) from the summer and winter of 2006. Sanger sequences were generated from the 0.1-0.8 μm fractions using paired-end medium insert shotgun libraries. The resulting 2.2 Gb were assembled using the Celera Assembler package into 280 Mb of non-redundant scaffolds. Putative actinobacterial assemblies were identified using (1) ribosomal RNA genes (16S and 23S), (2) phylogenetically informative non-ribosomal core genes thought to be resistant to horizontal gene transfer (e.g. RecA and RpoB) and (3) compositional binning using oligonucleotide frequency pattern based hierarchical clustering. Binning resulted in 3.6 Mb (4.2X coverage) of actinobacterial scaffolds that were comprised of 15.1 Mb of unassembled reads. Putative actinobacterial assemblies included both summer and winter reads demonstrating that the Actinobacteria are abundant year round. Classification reveals that all of the sampled Actinobacteria are from the orders Acidimicrobiales and Actinomycetales and are similar to those found in the global ocean. The GOM Actinobacteria show a broad range of G+C % content (32-66%) indicating a high level of genomic diversity. Those assemblies
Full Text Available Abstract Background Corynebacterium glutamicum is a high-GC Gram-positive soil bacterium of great biotechnological importance for the production of amino acids. To facilitate the rational design of sulphur amino acid-producing strains, the pathway for assimilatory sulphate reduction providing the necessary reduced sulfur moieties has to be known. Although this pathway has been well studied in Gram-negative bacteria like Escherichia coli and low-GC Gram-positives like Bacillus subtilis, little is known for the Actinomycetales and other high-GC Gram-positive bacteria. Results The genome sequence of C. glutamicum was searched for genes involved in the assimilatory reduction of inorganic sulphur compounds. A cluster of eight candidate genes could be identified by combining sequence similarity searches with a subsequent synteny analysis between C. glutamicum and the closely related C. efficiens. Using mutational analysis, seven of the eight candidate genes, namely cysZ, cysY, cysN, cysD, cysH, cysX, and cysI, were demonstrated to be involved in the reduction of inorganic sulphur compounds. For three of the up to now unknown genes possible functions could be proposed: CysZ is likely to be the sulphate permease, while CysX and CysY are possibly involved in electron transfer and cofactor biosynthesis, respectively. Finally, the candidate gene designated fpr2 influences sulphur utilisation only weakly and might be involved in electron transport for the reduction of sulphite. Real-time RT-PCR experiments revealed that cysIXHDNYZ form an operon and that transcription of the extended cluster fpr2 cysIXHDNYZ is strongly influenced by the availability of inorganic sulphur, as well as L-cysteine. Mapping of the fpr2 and cysIXHDNYZ promoters using RACE-PCR indicated that both promoters overlap with binding-sites of the transcriptional repressor McbR, suggesting an involvement of McbR in the observed regulation. Comparative genomics revealed that large parts of
Abbasian, Firouz; Lockington, Robin; Megharaj, Mallavarapu; Naidu, Ravi
Crude oil spills resulting from excavation, transportation and downstream processes can cause intensive damage to living organisms and result in changes in the microbial population of that environment. In this study, we used a pyrosequencing analysis to investigate changes in the microbial population of soils contaminated with crude oil. Crude oil contamination in soil resulted in the creation of a more homogenous population of microorganisms dominated by members of the Actinomycetales, Clostridiales and Bacillales (all belonging to Gram-positive bacteria) as well as Flavobacteriales, Pseudomonadales, Burkholderiales, Rhizobiales and Sphingomonadales (all belonging to Gram-negative bacteria). These changes in the biodiversity decreased the ratios of chemoheterotrophic bacteria at higher concentrations of crude oil contamination, with these being replaced by photoheterotrophic bacteria, mainly Rhodospirillales. Several of the dominant microbial orders in the crude oil contaminated soils are able to degrade crude oil hydrocarbons and therefore are potentially useful for remediation of crude oil in contaminated sites. PMID:26858133
Zotchev, Sergey B
Many representatives of the order Actinomycetales are prolific producers of thousands of biologically active secondary metabolites. Actinomycetes from terrestrial sources have been studied and screened since the 1950s, yielding many important anti-infective and anti-cancer drugs. However, frequent re-discovery of the same compounds in terrestrial actinomycetes have made them less attractive for screening programs in the recent years. At the same time, actinomycetes isolated from the marine environment currently receive considerable attention due to the structural diversity and unique biological activities of their secondary metabolites. This review highlights achievements and challenges in the isolation of marine actinomycetes, some examples of bioactive metabolites identified by conventional screening, and presents new developments in the field of genome mining and heterologous expression of biosynthetic gene clusters leading to the discovery of novel compounds. PMID:21683100
Copeland, Alex; Lapidus, Alla; Rio, Tijana GlavinaDel; Nolan, Matt; Lucas, Susan; Chen, Feng; Tice, Hope; Cheng, Jan-Fang; Bruce, David; Goodwin, Lynne; Pitluck, Sam; Mikhailova, Natalia; Pati, Amrita; Ivanova, Natalia; Mavromatis, Konstantinos; Chen, Amy; Palaniappan, Krishna; Chain, Patrick; Land, Miriam; Hauser, Loren; Chang, Yun-Juan; Jefferies, Cynthia C.; Chertkov, Olga; Brettin, Thomas; Detter, John C.; Han, Cliff; Ali, Zahid; Tindall, Brian J.; Goker, Markus; Bristow, James; Eisen, Jonathan A.; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C.; Klenk, Hans-Peter
Catenulispora acidiphila Busti et al. 2006 is the type species of the genus Catenulispora, and is of interest because of the rather isolated phylogenetic location of the genomically little studied suborder Catenulisporineae within the order Actinomycetales. C. acidiphilia is known for its acidophilic, aerobic lifestyle, but can also grow scantly under anaerobic conditions. Under regular conditions C. acidiphilia grows in long filaments of relatively short aerial hyphae with marked septation. It is a free living, non motile, Gram-positive bacterium isolated from a forest soil sample taken from a wooded area in Gerenzano, Italy. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first complete genome sequence of the actinobacterial family Catenulisporaceae, and the 10,467,782 bp long single replicon genome with its 9056 protein-coding and 69 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
Stanford, John; Stanford, Cynthia; Stansby, Gerard; Bottasso, Oscar; Bahr, Georges; Grange, John
The mycobacteria are one of a number of genera making up the aerobic Actinomycetales. Their antigens demonstrable by immuno-precipitation methods can be divided into four groups. The group i antigens, common to all mycobacterial species, cross-react with their counterparts in animal cells, largely derived from mitochondria. Notable amongst these antigens are the heat-shock, or stress, proteins and possibly bacterial sugars. Tests of cell-mediated immunity show that people can be separated by their responsiveness in skin-test, or lymphocyte proliferation techniques, into four categories of responders. Category 1 individuals respond to all mycobacterial reagents through recognition of the group i antigens. Many chronic diseases are associated with a lack of cell-mediated responsiveness to the group i antigens, and have a raised antibody titre to them. This reflects a predominance of T helper 2 activity and reduced T helper 1 responsiveness as part of the pathogenesis of their diseases, which include chronic bacterial, viral and parasitic infections, allergies, auto-immunities and neoplasms. Packaged together, the group i antigens and the cell-wall adjuvants of selected aerobic Actinomycetales make potent immuno-modulatory reagents. An example is heat-killed Mycobacterium vaccae, useful in both prevention and treatment of disease. Treatment with such reagents results in alleviation of disease, restoration of cellular responsiveness to the common mycobacterial antigens and a decrease in antibody titres to them. This new approach to treatment for such a wide range of diseases has few disadvantageous side effects and can accompany other non-immunosuppressive therapies. PMID:19355964
Jason W Holder
Full Text Available The Actinomycetales bacteria Rhodococcus opacus PD630 and Rhodococcus jostii RHA1 bioconvert a diverse range of organic substrates through lipid biosynthesis into large quantities of energy-rich triacylglycerols (TAGs. To describe the genetic basis of the Rhodococcus oleaginous metabolism, we sequenced and performed comparative analysis of the 9.27 Mb R. opacus PD630 genome. Metabolic-reconstruction assigned 2017 enzymatic reactions to the 8632 R. opacus PD630 genes we identified. Of these, 261 genes were implicated in the R. opacus PD630 TAGs cycle by metabolic reconstruction and gene family analysis. Rhodococcus synthesizes uncommon straight-chain odd-carbon fatty acids in high abundance and stores them as TAGs. We have identified these to be pentadecanoic, heptadecanoic, and cis-heptadecenoic acids. To identify bioconversion pathways, we screened R. opacus PD630, R. jostii RHA1, Ralstonia eutropha H16, and C. glutamicum 13032 for growth on 190 compounds. The results of the catabolic screen, phylogenetic analysis of the TAGs cycle enzymes, and metabolic product characterizations were integrated into a working model of prokaryotic oleaginy.
Infectious disease has always been and will continue to be a heavy burden on human society worldwide. Terrestrial actinobacteria, notable as a source of antibiotics, have been well investigated in the past. In constrast, marine actinobacteria, especially sponge-associated species, have received much less attention and isolates are sparse. With the aim of studying and discovering novel marine actinobacteria, 11 different species of sponges were collected from the Central Red Sea in Saudi Arabia and cultured with three different types of media. 16S rRNA gene-sequencing revealed that among all 75 isolated bacterial strains 13 belonged to the order actinomycetales. These 13 actinomycetes fall into four different families and can be assigned to six different genera. Antibiotic activity tests using disc diffusion assay were performed against Gram-positive bacteria (Bacillus sp.), Gram-negative bacteria (Escherichia coli), fungi (Fusarium sp.) and West Nile virus NS3 protease. Nine strains presented different level of bioactivity against these pathogens. These findings provide evidence that actinomycetes are presented in marine sponges and that they have the potential to be good candidates in the search for new effective antibiotic, antifungal, and antiviral compounds.
Huang, Jun; Yu, Zhen; Li, Mei-Hong; Li, Na; Zhou, Jun; Zheng, Yu-Guo
We report a novel method for the seamless cloning of large DNA fragments (SCLF) of up to 44 kb or larger from Streptomyces chromosomal DNA. SCLF is based on homologous recombination in Streptomyces and is easy to perform. The strategy of SCLF is to flank the target sequence in the chromosomal DNA with two identical restriction sites by the insertion of plasmids containing that site at either end of the fragment, which is then isolated by plasmid rescue through the self-ligation of restriction digested genomic DNA. The method involves three steps: (i) placing a certain restriction site (CRS) at the 3'-end of the target sequence by insertion through homologous recombination of a plasmid containing the CRS; (ii) inserting through homologous recombination at the 5'-end of the target sequence a linearized self-suicide vector with the identical CRS; (iii) digesting the genomic DNA with the certain restriction enzyme followed by self-ligation in order to plasmid rescue the target fragment. SCLF can be applied to other Actinomycetales, and further optimizations may reduce the amount of time required to perform this technique. PMID:26458547
The crystal structure of Rv2714, a protein of unknown function from M. tuberculosis, has been determined at 2.6 Å resolution using single-wavelength anomalous diffraction methods. The gene Rv2714 from Mycobacterium tuberculosis, which codes for a hypothetical protein of unknown function, is a representative member of a gene family that is largely confined to the order Actinomycetales of Actinobacteria. Sequence analysis indicates the presence of two paralogous genes in most mycobacterial genomes and suggests that gene duplication was an ancient event in bacterial evolution. The crystal structure of Rv2714 has been determined at 2.6 Å resolution, revealing a trimer in which the topology of the protomer core is similar to that observed in a functionally diverse set of enzymes, including purine nucleoside phosphorylases, some carboxypeptidases, bacterial peptidyl-tRNA hydrolases and even the plastidic form of an intron splicing factor. However, some structural elements, such as a β-hairpin insertion involved in protein oligomerization and a C-terminal α-helical domain that serves as a lid to the putative substrate-binding (or ligand-binding) site, are only found in Rv2714 bacterial homologues and represent specific signatures of this protein family
Goodwin, K. D.; Edsall, L.; Xin, W.; Head, S. R.; Gelbart, T.; Wood, A. M.; Gaasterland, T.
The methane ice worm (Hesiocaeca methanicola) is a polychaete found on methane hydrate deposits for which there appears to be no publically available genomic or metagenomic data. Methane ice worms were collected in 2009 by the Johnson-Sea-Link submersible (543m depth; N 27:44.7526 W 91:13.3168). Next-generation sequencing (HiSeq2000) was applied to samples of tissue and gut contents. A subset of the assembled data (40M reads, randomly selected) was run through MG-RAST. Preliminary results for the gut content (1,269,153 sequences, average length 202 bp) indicated that 0.1% of the sequences contained ribosomal RNA genes with the majority (67%) classified as Bacteria, a relatively small per cent (1.4%) as Archae, and 31% as Eukaryota. Campylobacterales was the predominant order (14%), with unclassified (7.5%) and Desulfobacterales (4%) being the next dominant. Preliminary results for the worm tissue (2,716,461 sequences, average length 241 bp) indicated that the majority of sequences were Eukaryota (73%), with 256 sequences classified as phylum Annelida and 58% of those belonging to class Polychaeta. For the bacterial sequences obtained from the tissue samples, the predominant order was Actinomycetales (2.7%). For both the tissue and gut content samples, the majority of proteins were classified as clustering-based subsystems. This preliminary analysis will be compared to an assembly consisting of 40M of the highest quality reads.; methane ice worms on methane hydrate
Layla Farage Martins
Full Text Available Composting operations are a rich source for prospection of biomass degradation enzymes. We have analyzed the microbiomes of two composting samples collected in a facility inside the São Paulo Zoo Park, in Brazil. All organic waste produced in the park is processed in this facility, at a rate of four tons/day. Total DNA was extracted and sequenced with Roche/454 technology, generating about 3 million reads per sample. To our knowledge this work is the first report of a composting whole-microbial community using high-throughput sequencing and analysis. The phylogenetic profiles of the two microbiomes analyzed are quite different, with a clear dominance of members of the Lactobacillus genus in one of them. We found a general agreement of the distribution of functional categories in the Zoo compost metagenomes compared with seven selected public metagenomes of biomass deconstruction environments, indicating the potential for different bacterial communities to provide alternative mechanisms for the same functional purposes. Our results indicate that biomass degradation in this composting process, including deconstruction of recalcitrant lignocellulose, is fully performed by bacterial enzymes, most likely by members of the Clostridiales and Actinomycetales orders.
Full Text Available During our continuous search for antibiotic producing actinomycetes, a variant of Streptomyces species was isolated from soils of Andhra Pradesh in India. The morphological, cultural, physiological and biochemical characters were studied, compared to known species and identified as a new variant of Streptomyces noursei and designated as Streptomyces noursei var saccharicus. The antibiotic activity of the strain was tested against both Gram-positive and Gram-negative bacteria as well as fungi and yeasts. INTRODUCTION Since the isolation of actinomycin in 1940 and streptomycin in 1944 by Waksman, the actinomycetes have received tremendous attention of the scientists. Soils, composts and fodders are common sources of actinomycetes. Waksman  recognized a few natural substrates as ideal sources for the isolation of actinomycetes and other streptomycetes. The nature of a Streptomyces colony is an important property in characterizing a culture. Krainsky  used the structure, size, shape and texture of the colony as one of the major diagnostic criteria. According to Pridham and Lyons  and International Subcommittee , the best way to handle streptomycete classification nomenclature and identification is through application of the genus-species-subspecies concept. The majority of antibiotic producing actinomycetes found in these species led to growing economic importance of these organisms which resulted in the isolation and description of numerous new species. It is reported that the only genus Streptomyces, the member of Actinomycetales accounts for approximately 93% producing secondary metabolites . The present communication deals with the isolation and characterization of an antibiotic producer from soils.
Abbasian, Firouz; Palanisami, Thavamani; Megharaj, Mallavarapu; Naidu, Ravi; Lockington, Robin; Ramadass, Kavitha
Soils contaminated with crude oil are rich sources of enzymes suitable for both degradation of hydrocarbons through bioremediation processes and improvement of crude oil during its refining steps. Due to the long term selection, crude oil fields are unique environments for the identification of microorganisms with the ability to produce these enzymes. In this metagenomic study, based on Hiseq Illumina sequencing of samples obtained from a crude oil field and analysis of data on MG-RAST, Actinomycetales (9.8%) were found to be the dominant microorganisms, followed by Rhizobiales (3.3%). Furthermore, several functional genes were found in this study, mostly belong to Actinobacteria (12.35%), which have a role in the metabolism of aliphatic and aromatic hydrocarbons (2.51%), desulfurization (0.03%), element shortage (5.6%), and resistance to heavy metals (1.1%). This information will be useful for assisting in the application of microorganisms in the removal of hydrocarbon contamination and/or for improving the quality of crude oil. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:638-648, 2016. PMID:26914145
Smith, Renee J; Paterson, James S; Sibley, Cally A; Hutson, John L; Mitchell, James G
Drought events and the overexploitation of freshwater resources have led to the increased need to manage groundwater reserves. Aquifer storage and recovery (ASR), whereby artificial water is injected into aquifers for storage, is one of the proposed methods by which freshwater supplies can be increased. Microbial clogging following injection, however, is a major issue. Here, during laboratory simulations of ASR, we used flow cytometry and bar-coded pyrosequencing to investigate changes in microbial abundance and community dynamics. Bacterial abundance ranged from 5.0 × 104 to 1.4 × 107 cells ml-1 before the addition of synthetic wastewater. Following wastewater addition, a 25-fold decrease in abundance was observed, coinciding with a 12-fold increase in viral abundance. Taxa shifted from an overrepresentation of Sphingomonadales, Sphingobacteriales, Rhodospirillales, Caulobacterales, Legionellales, Bacillales, Fusobacteriales and Verrucomicrobiales prior to the addition of synthetic wastewater to Burkholderiales, Actinomycetales, Pseudomonadales, Xanthomonadales, Rhodobacterales, Thizobiales and Thiotrichales following the addition of synthetic wastewater. Furthermore, a significant difference in overall taxonomic composition between the groundwater samples before and after the addition of synthetic wastewater was observed, with water samples exhibiting more similarity to sediment samples after wastewater was added. Collectively, these results suggest that ASR may alter the taxonomic composition of endemic microbial communities and that complete profiles of groundwater properties, including microbial community abundance and composition need to be taken into consideration when selecting aquifers for ASR practices. PMID:26083532
Reis, Izabela; Almeida, C Marisa R; Magalhães, Catarina M; Cochofel, Jaqueline; Guedes, Paula; Basto, M Clara P; Bordalo, Adriano A; Mucha, Ana P
The aim of this work was to evaluate the bioremediation potential of microorganisms from intertidal sediments of a sandy beach affected by a major oil spill 7 years before and subject to chronic petroleum contamination since then. For that, the response of microorganisms to a new oil contamination was assessed in terms of community structure, abundance, and capacity to degrade hydrocarbons. Experiments were carried out under laboratory-controlled conditions by mixing sediment with crude oil with three different nitrogen supplementations in 50 ml serum bottles under constant shake for 15 days. Autochthonous microorganisms were able to respond to the new oil contamination by increasing their abundance (quantified by DAPI) and changing the community structure (evaluated by DGGE). This response was particularly clear for some specific bacterial groups such as Pseudomonas, Actinomycetales, and Betaproteobacteria. These communities presented an important potential for hydrocarbon degradation (up to 85 % for TPHs and 70 % for total PAHs), being the biodegradation stimulated by addition of an appropriate amount of nitrogen. PMID:24271736
Styková, Eva; Nemcová, Radomíra; Gancarčíková, Soňa; Valocký, Igor; Lauková, Andrea
Kocuria spp. are widely distributed in nature. They are Gram-positive, coagulase-negative, coccoid bacteria belonging to the family Micrococcaceae, suborder Micrococcineae, order Actinomycetales, class Actinobacteria. In general, limited knowledge exists concerning the properties associated with the representants of the genus Kocuria, Kocuria kristinae as well. Following our previous results, K. kristinae Kk2014 Biocenol(™) (CCM 8628) was isolated from vagina of a healthy cow. Its taxonomical allottation was confirmed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) identification system and phenotypic characteristics. Kk2014 strain showed strong adherence capability to the vaginal mucus, produced organic acids which can play a role in prevention of unsuitable contamination, and showed in vitro antagonistic/antimicrobial activity against strains Arcanobacterium pyogenes CCM 5753, Fusobacterium necrophorum CCM 5982, Streptococcus equi subsp. zooepidemicus CCM 7316, and Gardnerella vaginalis CCM 6221. Antimicrobial activity ranged from 100 to 200 AU/mL, up to 32 mm in size, respectively. PMID:26494240
The use of cassava for the production of single cell protein includes two basic approaches: the selection of strains to utilize cassava carbohydrate for their growth and the improvement of these strains using classic mutagenesis and/or gene engineering techniques and tools. This paper describes molecular genetic procedures applied to increase the amylolytic abilities of the strains of Streptomyces and Thermomonospora genera which are efficient producers of a number of enzymes and to utilize cassava as a carbon source. The specific genes coding the production of alpha-amylase were isolated from Streptomyces limosus and Thermomonospora curvata and inserted into wide spectrum, multicopy plasmid vectors of streptomycetes. The increased dosage of these genes led to over production of alpha-amylases in a series of streptomycete recipients. It is intended that another representative of the order Actinomycetales, Corynebacterium manihot isolated from the cassava root, should be used as a recipient of the prepared wide-spectrum recombined plasmids bearing thermosensitive and thermostable genes (for improvement of utilizing the cassava starch). After verification of the suitability of C. manihot, the strain should be mutagenized to obtain mutants producing increased amounts of an essential amino acid which then would increase the nutritional value of the used microorganism. (author). 7 refs
Renee J Smith
Full Text Available Drought events and the overexploitation of freshwater resources have led to the increased need to manage groundwater reserves. Aquifer storage and recovery (ASR, whereby artificial water is injected into aquifers for storage, is one of the proposed methods by which freshwater supplies can be increased. Microbial clogging following injection, however, is a major issue. Here, during laboratory simulations of ASR, we used flow cytometry and bar-coded pyrosequencing to investigate changes in microbial abundance and community dynamics. Bacterial abundance ranged from 5.0 × 104 to 1.4 × 107 cells ml-1 before the addition of synthetic wastewater. Following wastewater addition, a 25-fold decrease in abundance was observed, coinciding with a 12-fold increase in viral abundance. Taxa shifted from an overrepresentation of Sphingomonadales, Sphingobacteriales, Rhodospirillales, Caulobacterales, Legionellales, Bacillales, Fusobacteriales and Verrucomicrobiales prior to the addition of synthetic wastewater to Burkholderiales, Actinomycetales, Pseudomonadales, Xanthomonadales, Rhodobacterales, Thizobiales and Thiotrichales following the addition of synthetic wastewater. Furthermore, a significant difference in overall taxonomic composition between the groundwater samples before and after the addition of synthetic wastewater was observed, with water samples exhibiting more similarity to sediment samples after wastewater was added. Collectively, these results suggest that ASR may alter the taxonomic composition of endemic microbial communities and that complete profiles of groundwater properties, including microbial community abundance and composition need to be taken into consideration when selecting aquifers for ASR practices.
Shi, YingWu; Zhang, Xuebing; Lou, Kai
Abstract Endophytic microorganisms reside within plant tissues and have often been found to promote plant growth. In this study, endophytic microorganisms were isolated from the roots, stems, leaves, and seeds of healthy drunken horse grass, Achnatherum inebrians (Hance) Keng (Poales: Poaceae), through the use of a grinding separation method and identified by a dual approach of morphological and physiological observation and 16S rRNA gene-based (for bacteria) and internal transcribed sequence-based (for fungi) molecular identification. The endophytes were then inoculated into liquid media for fermentation, and their crude extracts were employed for insecticidal activity tests using slide disc immersion and nebulization methods. A total of 89 bacteria species, which were classified into eight genera, Bacillus, Pseudomonas, Actinomyces, Corynebacterium, Acinetobacter, Sphingomonas, Paenibacillus, and Phyllobacterium, and two fungi, Claviceps and Chaetomium, were isolated. Of these species, isolates Streptomyces albus (Rossi-Doria) Waksman and Henrici (Actinomycetales: Streptomycetaceae) (GA) and Claviceps purpurea (Fr.) Tul. (Hypocreales: Clavicipitaceae) (PF-2) were shown to produce mortality rates of more than 90% in the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), after first and second screenings. The isolates PF-2 and GA associated with A. inebrians had significant insecticidal activities towards A. gossypii Glover (Hemiptera: Aphididae) and may provide a new biological resource for exploring a new microbial insecticide. PMID:24784492
Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Duan, Man-Li
Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure.
Salvitti, Lauren R; Wood, Susanna A; McNabb, Paul; Cary, Stephen Craig
Tetrodotoxin (TTX) is a potent neurotoxin found in the tissues of many taxonomically diverse organisms. Its origin has been the topic of much debate, with suggestions including endogenous production, acquisition through diet, and symbiotic bacterial synthesis. Bacterial production of TTX has been reported in isolates from marine biota, but at lower than expected concentrations. In this study, 102 strains were isolated from Pleurobranchaea maculata (Opisthobranchia) and Stylochoplana sp. (Platyhelminthes). Tetrodotoxin production was tested utilizing a recently developed sensitive method to detect the C9 base of TTX via liquid chromatography-mass spectrometry. Bacterial strains were characterized by sequencing a region of the 16S ribosomal RNA gene. To account for the possibility that TTX is produced by a consortium of bacteria, a series of experiments using marine broth spiked with various P. maculata tissues were undertaken. Sixteen unique strains from P. maculata and one from Stylochoplana sp. were isolated, representing eight different genera; Pseudomonadales, Actinomycetales, Oceanospirillales, Thiotrichales, Rhodobacterales, Sphingomonadales, Bacillales, and Vibrionales. Molecular fingerprinting of bacterial communities from broth experiments showed little change over the first four days. No C9 base or TTX was detected in isolates or broth experiments (past day 0), suggesting a culturable microbial source of TTX in P. maculata and Stylochoplana sp. is unlikely. PMID:25635464
Lauren R. Salvitti
Full Text Available Tetrodotoxin (TTX is a potent neurotoxin found in the tissues of many taxonomically diverse organisms. Its origin has been the topic of much debate, with suggestions including endogenous production, acquisition through diet, and symbiotic bacterial synthesis. Bacterial production of TTX has been reported in isolates from marine biota, but at lower than expected concentrations. In this study, 102 strains were isolated from Pleurobranchaea maculata (Opisthobranchia and Stylochoplana sp. (Platyhelminthes. Tetrodotoxin production was tested utilizing a recently developed sensitive method to detect the C9 base of TTX via liquid chromatography—mass spectrometry. Bacterial strains were characterized by sequencing a region of the 16S ribosomal RNA gene. To account for the possibility that TTX is produced by a consortium of bacteria, a series of experiments using marine broth spiked with various P. maculata tissues were undertaken. Sixteen unique strains from P. maculata and one from Stylochoplana sp. were isolated, representing eight different genera; Pseudomonadales, Actinomycetales, Oceanospirillales, Thiotrichales, Rhodobacterales, Sphingomonadales, Bacillales, and Vibrionales. Molecular fingerprinting of bacterial communities from broth experiments showed little change over the first four days. No C9 base or TTX was detected in isolates or broth experiments (past day 0, suggesting a culturable microbial source of TTX in P. maculata and Stylochoplana sp. is unlikely.
Bredow, C; Azevedo, J L; Pamphile, J A; Mangolin, C A; Rhoden, S A
Because of human population growth, increased food production and alternatives to conventional methods of biocontrol and development of plants such as the use of endophytic bacteria and fungi are required. One of the methods used to study microorganism diversity is sequencing of the 16S rRNA gene, which has several advantages, including universality, size, and availability of databases for comparison. The objective of this study was to analyze endophytic bacterial diversity in agricultural crops using published papers, sequence databases, and phylogenetic analysis. Fourteen papers were selected in which the ribosomal 16S rRNA gene was used to identify endophytic bacteria, in important agricultural crops, such as coffee, sugar cane, beans, corn, soybean, tomatoes, and grapes, located in different geographical regions (America, Europe, and Asia). The corresponding 16S rRNA gene sequences were selected from the NCBI database, aligned using the Mega 5.2 program, and phylogenetic analysis was undertaken. The most common orders present in the analyzed cultures were Bacillales, Enterobacteriales, and Actinomycetales and the most frequently observed genera were Bacillus, Pseudomonas, and Microbacterium. Phylogenetic analysis showed that only approximately 1.56% of the total sequences were not properly grouped, demonstrating reliability in the identification of microorganisms. This study identified the main genera found in endophytic bacterial cultures from plants, providing data for future studies on improving plant agriculture, biotechnology, endophytic bacterium prospecting, and to help understand relationships between endophytic bacteria and their interactions with plants. PMID:26345903
Singh, Ravindra Pal; Baghel, Ravi S; Reddy, C R K; Jha, Bhavanath
Epiphytic and endophytic bacteria associated with green macroalgae Ulva (U. fasciata and U. lactuca) and red macroalgae Gracilaria (G. corticata and G. dura) have been identified from three different seasons to evaluate the effect of quorum sensing (QS) molecules on carpospores liberation from Gracilaria dura. The bacterial isolates belonging to the orders Bacillales, Pseudomonadales, Alteromonadales, and Vibrionales were present in all seasons, whereas Actinomycetales and Enterobacteriales were confined to pre-monsoon and post-monsoon seasons, respectively. Among all the Gram-negative bacteria, seven isolates were found to produce different types of N-acyl homoserine lactones (AHLs). Interestingly, Shewanella algae produced five types of AHL: C4-HSL, HC4-HSL, C6-HSL, 3-oxo-C6-HSL, and 3-oxo-C12-HSL. Subsequently, the AHLs producing bacterial isolates were screened for carpospore liberation from G. dura and these isolates were found to positively induce carpospore liberation over the control. Also, observed that carpospore liberation increased significantly in C4- and C6-HSL treated cystocarps. Sodium dodecyl sulfate and native polyacrylamide gel electrophoresis of the total protein of the C4- and C6-HSL treated cystocarps showed two specific peptide bands of different molecular weights (50 kDa and 60 kDa) as compared to the control, confirming their indirect effect on carpospore liberation. PMID:25788899
Bergkemper, Fabian; Schöler, Anne; Engel, Marion; Lang, Friederike; Krüger, Jaane; Schloter, Michael; Schulz, Stefanie
Phosphorus (P) is an important macronutrient for all biota on earth but similarly a finite resource. Microorganisms play on both sides of the fence as they effectively mineralize organic and solubilize precipitated forms of soil phosphorus but conversely also take up and immobilize P. Therefore, we analysed the role of microbes in two beech forest soils with high and low P content by direct sequencing of metagenomic deoxyribonucleic acid. For inorganic P solubilization, a significantly higher microbial potential was detected in the P-rich soil. This trait especially referred to Candidatus Solibacter usiatus, likewise one of the dominating species in the data sets. A higher microbial potential for efficient phosphate uptake systems (pstSCAB) was detected in the P-depleted soil. Genes involved in P starvation response regulation (phoB, phoR) were prevalent in both soils. This underlines the importance of effective phosphate (Pho) regulon control for microorganisms to use alternative P sources during phosphate limitation. Predicted genes were primarily harboured by Rhizobiales, Actinomycetales and Acidobacteriales. PMID:26690731
Tytgat, Bjorn; Verleyen, Elie; Sweetlove, Maxime; D'hondt, Sofie; Clercx, Pia; Van Ranst, Eric; Peeters, Karolien; Roberts, Stephen; Namsaraev, Zorigto; Wilmotte, Annick; Vyverman, Wim; Willems, Anne
Antarctic soils are known to be oligotrophic and of having low buffering capacities. It is expected that this is particularly the case for inland high-altitude regions. We hypothesized that the bedrock type and the presence of macrobiota in these soils enforce a high selective pressure on their bacterial communities. To test this, we analyzed the bacterial community structure in 52 soil samples from the western Sør Rondane Mountains (Dronning Maud Land, East Antarctica), using the Illumina MiSeq platform in combination with ARISA fingerprinting. The samples were taken along broad environmental gradients in an area covering nearly 1000 km(2) Ordination and variation partitioning analyses revealed that the total organic carbon content was the most significant variable in structuring the bacterial communities, followed by pH, electric conductivity, bedrock type and the moisture content, while spatial distance was of relatively minor importance. Acidobacteria (Chloracidobacteria) and Actinobacteria (Actinomycetales) dominated gneiss derived mineral soil samples, while Proteobacteria (Sphingomonadaceae), Cyanobacteria, Armatimonadetes and candidate division FBP-dominated soil samples with a high total organic carbon content that were mainly situated on granite derived bedrock. PMID:27402710
de Camargo, André Ferreira; Goulart, Karla Cristina Stropa; Lemos, Eliana Gertrudes de Macedo
Although the use of vinasse as a waste helps replenish soil nutrients and improves the quality of the sugarcane crop, it is known that vinasse residues alter the diversity of bacteria naturally present in the soil. The actual impacts of vinasse application on the selection of bacterial taxa are not understood because no studies have addressed this phenomenon directly. Analysis of 16S rRNA gene clone sequences from four soil types showed that the soil planted with sugarcane and fertilized with vinasse has a high diversity of bacteria compared to other biomes, where Acidobacteria were the second most abundant phylum. Although the composition and structure of bacterial communities differ significantly in the four environments (Libshuff's test), forest soils and soil planted with sugarcane without vinasse fertilizer were similar to each other because they share at least 28 OTUs related to Rhizobiales, which are important agents involved in nitrogen fixation. OTUs belonging to Actinomycetales were detected more often in the soil that had vinasse applied, indicating that these groups are more favored by this type of land management. PMID:27528875
Full Text Available Dairy propionibacteria are actinomycetales found in various fermented food products. The main species, Propionibacterium freudenreichii, is generally recognized as safe and used both as probiotic and as cheese starter. Its probiotic efficacy tightly depends on its tolerance towards digestive stresses, which can be largely modulated by the ingested delivery vehicle. Indeed, tolerance of this bacterium is enhanced when it is consumed within a fermented dairy product, compared to a dried probiotic preparation. We investigated both stress tolerance and protein neosynthesis upon growth in i chemically defined or ii aqueous phase of Emmental cheeses. Although the same final population level was reached in both media, a slower growth and an enhanced survival of CIRM BIA 1 strain of P. freudenreichii subsp. shermanii was observed in Emmental juice, compared to chemically defined medium. This was accompanied by differences in substrates used and products released as well as overexpression of various early stress adaptation proteins in Emmental juice, compared to chemically defined medium, implied in protein folding, in aspartate catabolism, in biosynthesis of valine, leucine and isoleucine, in pyruvate metabolism in citrate cycle, in the propionate metabolism, as well as in oxidoreductases. All these changes led to a higher digestive stress tolerance after growth in Emmental juice. Mechanisms of stress adaptation were induced in this environment, in accordance with enhanced survival. This opens perspectives for the use of hard and semi-hard cheeses as delivery vehicle for probiotics with enhanced efficacy.
Barton, Hazel A; Giarrizzo, Juan G; Suarez, Paula; Robertson, Charles E; Broering, Mark J; Banks, Eric D; Vaishampayan, Parag A; Venkateswaran, Kasthisuri
The majority of caves are formed within limestone rock and hence our understanding of cave microbiology comes from carbonate-buffered systems. In this paper, we describe the microbial diversity of Roraima Sur Cave (RSC), an orthoquartzite (SiO4) cave within Roraima Tepui, Venezuela. The cave contains a high level of microbial activity when compared with other cave systems, as determined by an ATP-based luminescence assay and cell counting. Molecular phylogenetic analysis of microbial diversity within the cave demonstrates the dominance of Actinomycetales and Alphaproteobacteria in endolithic bacterial communities close to the entrance, while communities from deeper in the cave are dominated (82-84%) by a unique clade of Ktedonobacterales within the Chloroflexi. While members of this phylum are commonly found in caves, this is the first identification of members of the Class Ktedonobacterales. An assessment of archaeal species demonstrates the dominance of phylotypes from the Thaumarchaeota Group I.1c (100%), which have previously been associated with acidic environments. While the Thaumarchaeota have been seen in numerous cave systems, the dominance of Group I.1c in RSC is unique and a departure from the traditional archaeal community structure. Geochemical analysis of the cave environment suggests that water entering the cave, rather than the nutrient-limited orthoquartzite rock, provides the carbon and energy necessary for microbial community growth and subsistence, while the poor buffering capacity of quartzite or the low pH of the environment may be selecting for this unusual community structure. Together these data suggest that pH, imparted by the geochemistry of the host rock, can play as important a role in niche-differentiation in caves as in other environmental systems. PMID:25505450
Gandolfi, I; Bertolini, V; Bestetti, G; Ambrosini, R; Innocente, E; Rampazzo, G; Papacchini, M; Franzetti, A
The study of spatio-temporal variability of airborne bacterial communities has recently gained importance due to the evidence that airborne bacteria are involved in atmospheric processes and can affect human health. In this work, we described the structure of airborne microbial communities in two urban areas (Milan and Venice, Northern Italy) through the sequencing, by the Illumina platform, of libraries containing the V5-V6 hypervariable regions of the 16S rRNA gene and estimated the abundance of airborne bacteria with quantitative PCR (qPCR). Airborne microbial communities were dominated by few taxa, particularly Burkholderiales and Actinomycetales, more abundant in colder seasons, and Chloroplasts, more abundant in warmer seasons. By partitioning the variation in bacterial community structure, we could assess that environmental and meteorological conditions, including variability between cities and seasons, were the major determinants of the observed variation in bacterial community structure, while chemical composition of atmospheric particulate matter (PM) had a minor contribution. Particularly, Ba, SO4 (2-) and Mg(2+) concentrations were significantly correlated with microbial community structure, but it was not possible to assess whether they simply co-varied with seasonal shifts of bacterial inputs to the atmosphere, or their variation favoured specific taxa. Both local sources of bacteria and atmospheric dispersal were involved in the assembling of airborne microbial communities, as suggested, to the one side by the large abundance of bacteria typical of lagoon environments (Rhodobacterales) observed in spring air samples from Venice and to the other by the significant effect of wind speed in shaping airborne bacterial communities at all sites. PMID:25592734
Groudieva, Tatiana; Kambourova, Margarita; Yusef, Hoda; Royter, Maryna; Grote, Ralf; Trinks, Hauke; Antranikian, Garabed
The diversity of culturable bacteria associated with sea ice from four permanently cold fjords of Spitzbergen, Arctic Ocean, was investigated. A total of 116 psychrophilic and psychrotolerant strains were isolated under aerobic conditions at 4 degrees C. The isolates were grouped using amplified rDNA restriction analysis fingerprinting and identified by partial sequencing of 16S rRNA gene. The bacterial isolates fell in five phylogenetic groups: subclasses alpha and gamma of Proteobacteria, the Bacillus-Clostridium group, the order Actinomycetales, and the Cytophaga-Flexibacter-Bacteroides (CFB) phylum. Over 70% of the isolates were affiliated with the Proteobacteria gamma subclass. Based on phylogenetic analysis (<98% sequence similarity), over 40% of Arctic isolates represent potentially novel species or genera. Most of the isolates were psychrotolerant and grew optimally between 20 and 25 degrees C. Only a few strains were psychrophilic, with an optimal growth at 10-15 degrees C. The majority of the bacterial strains were able to secrete a broad range of cold-active hydrolytic enzymes into the medium at a cultivation temperature of 4 degrees C. The isolates that are able to degrade proteins (skim milk, casein), lipids (olive oil), and polysaccharides (starch, pectin) account for, respectively, 56, 31, and 21% of sea-ice and seawater strains. The temperature dependences for enzyme production during growth and enzymatic activity were determined for two selected enzymes, alpha-amylase and beta-galactosidase. Interestingly, high levels of enzyme productions were measured at growth temperatures between 4 and 10 degrees C, and almost no production was detected at higher temperatures (20-30 degrees C). Catalytic activity was detected even below the freezing point of water (at -5 degrees C), demonstrating the unique properties of these enzymes. PMID:15252724
Montaña, José Salvador; Jiménez, Diego Javier; Hernández, Mónica; Angel, Tatiana; Baena, Sandra
Total metagenomic DNA was isolated from high Andean forest soil and subjected to taxonomical and functional composition analyses by means of clone library generation and sequencing. The obtained yield of 1.7 μg of DNA/g of soil was used to construct a metagenomic library of approximately 20,000 clones (in the plasmid p-Bluescript II SK+) with an average insert size of 4 Kb, covering 80 Mb of the total metagenomic DNA. Metagenomic sequences near the plasmid cloning site were sequenced and them trimmed and assembled, obtaining 299 reads and 31 contigs (0.3 Mb). Taxonomic assignment of total sequences was performed by BLASTX, resulting in 68.8, 44.8 and 24.5% classification into taxonomic groups using the metagenomic RAST server v2.0, WebCARMA v1.0 online system and MetaGenome Analyzer v3.8 software, respectively. Most clone sequences were classified as Bacteria belonging to phlya Actinobacteria, Proteobacteria and Acidobacteria. Among the most represented orders were Actinomycetales (34% average), Rhizobiales, Burkholderiales and Myxococcales and with a greater number of sequences in the genus Mycobacterium (7% average), Frankia, Streptomyces and Bradyrhizobium. The vast majority of sequences were associated with the metabolism of carbohydrates, proteins, lipids and catalytic functions, such as phosphatases, glycosyltransferases, dehydrogenases, methyltransferases, dehydratases and epoxide hydrolases. In this study we compared different methods of taxonomic and functional assignment of metagenomic clone sequences to evaluate microbial diversity in an unexplored soil ecosystem, searching for putative enzymes of biotechnological interest and generating important information for further functional screening of clone libraries. PMID:21792685
Goldfarb, K.C.; Karaoz, U.; Hanson, C.A.; Santee, C.A.; Bradford, M.A.; Treseder, K.K.; Wallenstein, M.D.; Brodie, E.L.
Soils are immensely diverse microbial habitats with thousands of co-existing bacterial, archaeal, and fungal species. Across broad spatial scales, factors such as pH and soil moisture appear to determine the diversity and structure of soil bacterial communities. Within any one site however, bacterial taxon diversity is high and factors maintaining this diversity are poorly resolved. Candidate factors include organic substrate availability and chemical recalcitrance, and given that they appear to structure bacterial communities at the phylum level, we examine whether these factors might structure bacterial communities at finer levels of taxonomic resolution. Analyzing 16S rRNA gene composition of nucleotide analog-labeled DNA by PhyloChip microarrays, we compare relative growth rates on organic substrates of increasing chemical recalcitrance of >2,200 bacterial taxa across 43 divisions/phyla. Taxa that increase in relative abundance with labile organic substrates (i.e., glycine, sucrose) are numerous (>500), phylogenetically clustered, and occur predominantly in two phyla (Proteobacteria and Actinobacteria) including orders Actinomycetales, Enterobacteriales, Burkholderiales, Rhodocyclales, Alteromonadales, and Pseudomonadales. Taxa increasing in relative abundance with more chemically recalcitrant substrates (i.e., cellulose, lignin, or tannin-protein) are fewer (168) but more phylogenetically dispersed, occurring across eight phyla and including Clostridiales, Sphingomonadalaes, Desulfovibrionales. Just over 6% of detected taxa, including many Burkholderiales increase in relative abundance with both labile and chemically recalcitrant substrates. Estimates of median rRNA copy number per genome of responding taxa demonstrate that these patterns are broadly consistent with bacterial growth strategies. Taken together, these data suggest that changes in availability of intrinsically labile substrates may result in predictable shifts in soil bacterial composition.
Mariana Gabriela Ghinet
Full Text Available Horizontal gene transfer greatly facilitates rapid genetic adaptation of bacteria to shifts in environmental conditions and colonization of new niches by allowing one-step acquisition of novel functions. Conjugation is a major mechanism of horizontal gene transfer mediated by conjugative plasmids and integrating conjugative elements (ICEs. While in most bacterial conjugative systems DNA translocation requires the assembly of a complex type IV secretion system (T4SS, in Actinobacteria a single DNA FtsK/SpoIIIE-like translocation protein is required. To date, the role and diversity of ICEs in Actinobacteria have received little attention. Putative ICEs were searched for in 275 genomes of Actinobacteria using HMM-profiles of proteins involved in ICE maintenance and transfer. These exhaustive analyses revealed 144 putative FtsK/SpoIIIE-type ICEs and 17 putative T4SS-type ICEs. Grouping of the ICEs based on the phylogenetic analyses of maintenance and transfer proteins revealed extensive exchanges between different sub-families of ICEs. 17 ICEs were found in Actinobacteria from the genus Frankia, globally important nitrogen-fixing microorganisms that establish root nodule symbioses with actinorhizal plants. Structural analysis of ICEs from Frankia revealed their unexpected diversity and a vast array of predicted adaptive functions. Frankia ICEs were found to excise by site-specific recombination from their host's chromosome in vitro and in planta suggesting that they are functional mobile elements whether Frankiae live as soil saprophytes or plant endosymbionts. Phylogenetic analyses of proteins involved in ICEs maintenance and transfer suggests that active exchange between ICEs cargo-borne and chromosomal genes took place within the Actinomycetales order. Functionality of Frankia ICEs in vitro as well as in planta lets us anticipate that conjugation and ICEs could allow the development of genetic manipulation tools for this challenging microorganism
Kao, Wei-Chun; Kleinschroth, Thomas; Nitschke, Wolfgang; Baymann, Frauke; Neehaul, Yashvin; Hellwig, Petra; Richers, Sebastian; Vonck, Janet; Bott, Michael; Hunte, Carola
Actinobacteria are closely linked to human life as industrial producers of bioactive molecules and as human pathogens. Respiratory cytochrome bcc complex and cytochrome aa3 oxidase are key components of their aerobic energy metabolism. They form a supercomplex in the actinobacterial species Corynebacterium glutamicum. With comprehensive bioinformatics and phylogenetic analysis we show that genes for cyt bcc-aa3 supercomplex are characteristic for Actinobacteria (Actinobacteria and Acidimicrobiia, except the anaerobic orders Actinomycetales and Bifidobacteriales). An obligatory supercomplex is likely, due to the lack of genes encoding alternative electron transfer partners such as mono-heme cyt c. Instead, subunit QcrC of bcc complex, here classified as short di-heme cyt c, will provide the exclusive electron transfer link between the complexes as in C. glutamicum. Purified to high homogeneity, the C. glutamicum bcc-aa3 supercomplex contained all subunits and cofactors as analyzed by SDS-PAGE, BN-PAGE, absorption and EPR spectroscopy. Highly uniform supercomplex particles in electron microscopy analysis support a distinct structural composition. The supercomplex possesses a dimeric stoichiometry with a ratio of a-type, b-type and c-type hemes close to 1:1:1. Redox titrations revealed a low potential bcc complex (Em(ISP)=+160mV, Em(bL)=-291mV, Em(bH)=-163mV, Em(cc)=+100mV) fined-tuned for oxidation of menaquinol and a mixed potential aa3 oxidase (Em(CuA)=+150mV, Em(a/a3)=+143/+317mV) mediating between low and high redox potential to accomplish dioxygen reduction. The generated molecular model supports a stable assembled supercomplex with defined architecture which permits energetically efficient coupling of menaquinol oxidation and dioxygen reduction in one supramolecular entity. PMID:27472998
Raymon S Shange
Full Text Available Land-use change and management practices are normally enacted to manipulate environments to improve conditions that relate to production, remediation, and accommodation. However, their effect on the soil microbial community and their subsequent influence on soil function is still difficult to quantify. Recent applications of molecular techniques to soil biology, especially the use of 16S rRNA, are helping to bridge this gap. In this study, the influence of three land-use systems within a demonstration farm were evaluated with a view to further understand how these practices may impact observed soil bacterial communities. Replicate soil samples collected from the three land-use systems (grazed pine forest, cultivated crop, and grazed pasture on a single soil type. High throughput 16S rRNA gene pyrosequencing was used to generate sequence datasets. The different land use systems showed distinction in the structure of their bacterial communities with respect to the differences detected in cluster analysis as well as diversity indices. Specific taxa, particularly Actinobacteria, Acidobacteria, and classes of Proteobacteria, showed significant shifts across the land-use strata. Families belonging to these taxa broke with notions of copio- and oligotrphy at the class level, as many of the less abundant groups of families of Actinobacteria showed a propensity for soil environments with reduced carbon/nutrient availability. Orders Actinomycetales and Solirubrobacterales showed their highest abundance in the heavily disturbed cultivated system despite the lowest soil organic carbon (SOC values across the site. Selected soil properties ([SOC], total nitrogen [TN], soil texture, phosphodiesterase [PD], alkaline phosphatase [APA], acid phosphatase [ACP] activity, and pH also differed significantly across land-use regimes, with SOM, PD, and pH showing variation consistent with shifts in community structure and composition. These results suggest that use of
Babujia, Letícia Carlos; Silva, Adriana Pereira; Nakatani, André Shigueyoshi; Cantão, Mauricio Egidio; Vasconcelos, Ana Tereza Ribeiro; Visentainer, Jesuí Vergilio; Hungria, Mariangela
The transgenic soybean [Glycine max (L.) Merrill] occupies about 80 % of the global area cropped with this legume, the majority comprising the glyphosate-resistant trait (Roundup Ready(®), GR or RR). However, concerns about possible impacts of transgenic crops on soil microbial communities are often raised. We investigated soil chemical, physical and microbiological properties, and grain yields in long-term field trials involving conventional and nearly isogenic RR transgenic genotypes. The trials were performed at two locations in Brazil, with different edaphoclimatic conditions. Large differences in physical, chemical and classic microbiological parameters (microbial biomass of C and N, basal respiration), as well as in grain production were observed between the sites. Some phyla (Proteobacteria, Actinobacteria, Acidobacteria), classes (Alphaproteobacteria, Actinomycetales, Solibacteres) and orders (Rhizobiales, Burkholderiales, Myxococcales, Pseudomonadales), as well as some functional subsystems (clustering-based subsystems, carbohydrates, amino acids and protein metabolism) were, in general, abundant in all treatments. However, bioindicators related to superior soil fertility and physical properties at Londrina were identified, among them a higher ratio of Proteobacteria:Acidobacteria. Regarding the transgene, the metagenomics showed differences in microbial taxonomic and functional abundances, but lower in magnitude than differences observed between the sites. Besides the site-specific differences, Proteobacteria, Firmicutes and Chlorophyta were higher in the transgenic treatment, as well as sequences related to protein metabolism, cell division and cycle. Although confirming effects of the transgenic trait on soil microbiome, no differences were recorded in grain yields, probably due to the buffering capacity associated with the high taxonomic and functional microbial diversity observed in all treatments. PMID:26873023
Cataldi Angel A
Full Text Available Abstract Background The exported repetitive protein (erp gene encodes a secreted 36-kDa protein with a central domain containing several proline-glycine-leucine-threonine-serine (PGLTS repeats. It has been demonstrated that erp is a virulence-associated factor since the disruption of this gene impairs the growth of Mycobacterium bovis and Mycobacterium tuberculosis in mice. Results In order to elucidate the function of Erp we searched for Erp-binding proteins from M. tuberculosis by using a bacterial two-hybrid system. Our results indicate that Erp interacts specifically with two putative membrane proteins, Rv1417 and Rv2617c. Further analysis revealed that the latter two interact with each other, indicating that Rv1417, Rv2617c and Erp are connected through multiple interactions. While Rv1417 is disseminated in several Actinomycetales genera, orthologues of Rv2617c are exclusively present in members of the M. tuberculosis complex (MTC. The central and amino-terminal regions of Erp were determined to be involved in the interaction with Rv1417 and Rv2627c. Erp forms from Mycobacterium smegmatis and Mycobacterium leprae were not able to interact with Rv2617c in two-hybrid assays. Immunolocalization experiments showed that Rv1417 and Rv2617c are found on the cell membrane and Erp on the bacterial cell wall. Finally, comparative genomics and expression studies revealed a possible role of Rv1417 in riboflavin metabolism. Conclusion We identified interactive partners of Erp, an M. tuberculosis protein involved in virulence, which will be the focus of future investigation to decipher the function of the Erp family protein.
Riquelme, Cristina; Marshall Hathaway, Jennifer J.; Enes Dapkevicius, Maria de L. N.; Miller, Ana Z.; Kooser, Ara; Northup, Diana E.; Jurado, Valme; Fernandez, Octavio; Saiz-Jimenez, Cesareo; Cheeptham, Naowarat
Volcanic caves are filled with colorful microbial mats on the walls and ceilings. These volcanic caves are found worldwide, and studies are finding vast bacteria diversity within these caves. One group of bacteria that can be abundant in volcanic caves, as well as other caves, is Actinobacteria. As Actinobacteria are valued for their ability to produce a variety of secondary metabolites, rare and novel Actinobacteria are being sought in underexplored environments. The abundance of novel Actinobacteria in volcanic caves makes this environment an excellent location to study these bacteria. Scanning electron microscopy (SEM) from several volcanic caves worldwide revealed diversity in the morphologies present. Spores, coccoid, and filamentous cells, many with hair-like or knobby extensions, were some of the microbial structures observed within the microbial mat samples. In addition, the SEM study pointed out that these features figure prominently in both constructive and destructive mineral processes. To further investigate this diversity, we conducted both Sanger sequencing and 454 pyrosequencing of the Actinobacteria in volcanic caves from four locations, two islands in the Azores, Portugal, and Hawai'i and New Mexico, USA. This comparison represents one of the largest sequencing efforts of Actinobacteria in volcanic caves to date. The diversity was shown to be dominated by Actinomycetales, but also included several newly described orders, such as Euzebyales, and Gaiellales. Sixty-two percent of the clones from the four locations shared less than 97% similarity to known sequences, and nearly 71% of the clones were singletons, supporting the commonly held belief that volcanic caves are an untapped resource for novel and rare Actinobacteria. The amplicon libraries depicted a wider view of the microbial diversity in Azorean volcanic caves revealing three additional orders, Rubrobacterales, Solirubrobacterales, and Coriobacteriales. Studies of microbial ecology in
Navarrete, Acacio A; Tsai, Siu M; Mendes, Lucas W; Faust, Karoline; de Hollander, Mattias; Cassman, Noriko A; Raes, Jeroen; van Veen, Johannes A; Kuramae, Eiko E
Slash-and-burn clearing of forest typically results in increase in soil nutrient availability. However, the impact of these nutrients on the soil microbiome is not known. Using next generation sequencing of 16S rRNA gene and shotgun metagenomic DNA, we compared the structure and the potential functions of bacterial community in forest soils to deforested soils in the Amazon region and related the differences to soil chemical factors. Deforestation decreased soil organic matter content and factors linked to soil acidity and raised soil pH, base saturation and exchangeable bases. Concomitant to expected changes in soil chemical factors, we observed an increase in the alpha diversity of the bacterial microbiota and relative abundances of putative copiotrophic bacteria such as Actinomycetales and a decrease in the relative abundances of bacterial taxa such as Chlamydiae, Planctomycetes and Verrucomicrobia in the deforested soils. We did not observe an increase in genes related to microbial nutrient metabolism in deforested soils. However, we did observe changes in community functions such as increases in DNA repair, protein processing, modification, degradation and folding functions, and these functions might reflect adaptation to changes in soil characteristics due to forest clear-cutting and burning. In addition, there were changes in the composition of the bacterial groups associated with metabolism-related functions. Co-occurrence microbial network analysis identified distinct phylogenetic patterns for forest and deforested soils and suggested relationships between Planctomycetes and aluminium content, and Actinobacteria and nitrogen sources in Amazon soils. The results support taxonomic and functional adaptations in the soil bacterial community following deforestation. We hypothesize that these microbial adaptations may serve as a buffer to drastic changes in soil fertility after slash-and-burning deforestation in the Amazon region. PMID:25809788
Streptomycetes are gram-positive, soil-inhabiting bacteria of the order Actinomycetales. These organisms exhibit an unusual, developmentally complex life cycle and produce many economically important secondary metabolites, such as antibiotics, immunosuppressants, insecticides, and antitumor agents. Streptomyces species have been the subject of genetic investigation for over 50 years, with many studies focusing on the production of bioactives compounds. The protoplast formation and regeneration are important processes, and they are a major step following genetic manipulations such as fusion and DNA-mediated transformation, which can improve antibiotic production. The protoplast fusion, transformation and improved fermentation features can be used to regenerate strains with increased antibiotic activity. Local Streptomyces spp. CN207 produce a broad range of secondary metabolites which is active against bacteria and fungi. This strain was used as a donor and S. coelicolor strain M145 was used as a recipient host for protoplast fusion. The protoplast fusion resulted in increased isolation of variants with higher antibiotic activity. Recombinant Streptomyces coelicolor PF04 was increased 10 times more than the wild strain. The antimicrobial activity from PF04 strain was studied using the disc method agar. TLC analysis confirmed that the Rf of cell extract for PF04 strain is identical to antimicrobial compound of Streptomyces CN207. Our results confirm the possibility of transferring antibiotics cluster genes by fusion. In fact, many of the selective markers such as Ticarcillin, Cefalotin, Oxacillin and Cefotaxim were transferred during the protoplast fusion. PFGE analysis and DNA-hybridization confirmed the presence of homologous fragments between a wild-type Streptomyces CN207 and a recombinant S. coelicolor PF04
Prunner, Isabella; Wagener, Karen; Pothmann, Harald; Ehling-Schulz, Monika; Drillich, Marc
The involution process of the postpartum bovine uterus is usually accompanied by invasion of various bacteria. The objectives of this study were to identify the relationship between the postpartum findings as risk factors for clinical endometritis (CE) and subclinical endometritis (SE). Furthermore, the effects of CE or SE on reproductive performance in small- and medium-sized dairy herds were investigated. A total of 400 cows were examined by vaginoscopy for CE at 20 to 30 days postpartum, and samples were collected for cytological examinations for SE and for bacteriology by cytobrush technique. The vaginoscopic and cytological examinations showed that 27.3% and 21.0% of the cows were found with CE and SE, respectively. The bacterial community analyses revealed a large variety of bacteria. Overall, bacteria from the order Actinomycetales, Lactobacillales, Bacillales, Burkholderiales, Caulobacteriales Enterobacteriales, Pasteurellales, and Pseudomonadales were detected, whereas in 39.5% of the samples no bacterial growth was detectable. The uterine pathogens Escherichia coli and Trueperella pyogenes were found in 16.8% and 13.0% of the samples cultivated under aerobic conditions. Other frequently isolated bacteria were Streptococcus spp. (31.3%), Staphylococcus spp. (20.0%), Corynebacterium spp. (16.5%), and Bacillus spp. (10.5%). The infection with T. pyogenes was the most important bacteriological risk factor for the occurrence of CE (odds ratio (OR) = 5.72; 95% CI = 3.07-10.83) and had a detrimental effect on the hazard of nonpregnancy by 200 days postpartum (hazard ratio = 1.66; 95% CI = 1.12-2.46). Calving assistance (OR = 1.79; 95% CI = 1.16-2.98) and farm (OR = 1.11; 95% CI = 1.02-1.20) were indicated as further risk factors for CE and SE. Effects of CE and SE on reproductive performance parameters could not be demonstrated. PMID:25066047
Kim A Caldwell
Full Text Available Parkinson disease (PD involves progressive neurodegeneration, including loss of dopamine (DA neurons from the substantia nigra. Select genes associated with rare familial forms of PD function in cellular pathways, such as the ubiquitin-proteasome system (UPS, involved in protein degradation. The misfolding and accumulation of proteins, such as alpha-synuclein, into inclusions termed Lewy Bodies represents a clinical hallmark of PD. Given the predominance of sporadic PD among patient populations, environmental toxins may induce the disease, although their nature is largely unknown. Thus, an unmet challenge surrounds the discovery of causal or contributory neurotoxic factors that could account for the prevalence of sporadic PD. Bacteria within the order Actinomycetales are renowned for their robust production of secondary metabolites and might represent unidentified sources of environmental exposures. Among these, the aerobic genera, Streptomyces, produce natural proteasome inhibitors that block protein degradation and may potentially damage DA neurons. Here we demonstrate that a metabolite produced by a common soil bacterium, S. venezuelae, caused DA neurodegeneration in the nematode, Caenorhabditis elegans, which increased as animals aged. This metabolite, which disrupts UPS function, caused gradual degeneration of all neuronal classes examined, however DA neurons were particularly vulnerable to exposure. The presence of DA exacerbated toxicity because neurodegeneration was attenuated in mutant nematodes depleted for tyrosine hydroxylase (TH, the rate-limiting enzyme in DA production. Strikingly, this factor caused dose-dependent death of human SH-SY5Y neuroblastoma cells, a dopaminergic line. Efforts to purify the toxic activity revealed that it is a highly stable, lipophilic, and chemically unique small molecule. Evidence of a robust neurotoxic factor that selectively impacts neuronal survival in a progressive yet moderate manner is consistent
Full Text Available Mycetoma is a neglected, chronic, localized, progressively destructive, granulomatous infection caused either by fungi (eumycetoma or by aerobic actinomycetes (actinomycetoma. It is characterized by a triad of painless subcutaneous mass, multiple sinuses and discharge containing grains. Mycetoma commonly affects young men aged between 20 and 40 years with low socioeconomic status, particularly farmers and herdsmen.A 30 year-old male farmer from an ethnic minority in Phin District, Savannakhet Province, Lao PDR (Laos developed a painless swelling with multiple draining sinuses of his right foot over a period of approximately 3 years. X-ray of the right foot showed osteolysis of tarsals and metatarsals. Aerobic culture of sinus discharge yielded large numbers of Staphylococcus aureus and a slow growing Gram-positive rod. The organism was subsequently identified as Nocardia aobensis by 16S ribosomal RNA gene sequencing. The patient received antimicrobial treatment with amikacin and trimethoprim-sulfamethoxazole according to consensus treatment guidelines. Although slight improvement was noted the patient left the hospital after 14 days and did not take any more antibiotics. Over the following 22 weeks the swelling of his foot subsequently diminished together with healing of discharging sinuses.This is the first published case of Actinomycetoma caused by Nocardia aobensis and the second case of Actinomycetoma from Laos. A treatment course of only 14 days with amikacin and trimethoprim-sulfamethoxazole was apparently sufficient to cure the infection, although long-term treatment up to one year is currently recommended. Treatment trials or prospective descriptions of outcome for actinomycetoma should investigate treatment efficacy for the different members of Actinomycetales, particularly Nocardia spp., with short-term and long-term treatment courses.
Katherine C Goldfarb
Full Text Available Soils are immensely diverse microbial habitats with thousands of co-existing bacterial, archaeal and fungal species. Across broad spatial scales, factors such as pH and soil moisture appear to determine the diversity and structure of soil bacterial communities. Within any one site however, bacterial taxon diversity is high and factors maintaining this diversity are poorly resolved. Candidate factors include organic substrate availability and chemical recalcitrance, and given that they appear to structure bacterial communities at the phylum-level, we examine whether these factors might structure bacterial communities at finer levels of taxonomic resolution. Analyzing 16S rRNA gene composition of nucleotide analog-labeled DNA by PhyloChip microarrays, we compare relative growth rates on organic substrates of increasing chemical recalcitrance of >2,200 bacterial taxa across 43 divisions/phyla. Taxa that increase in relative abundance with labile organic substrates (i.e. glycine, sucrose are numerous (>500, phylogenetically-clustered, and occur predominantly in two phyla (Proteobacteria and Actinobacteria including orders Actinomycetales, Enterobacterales, Burkholderiales, Rhodocyclales, Alteromonadales and Pseudomonadales. Taxa increasing in relative abundance with more chemically recalcitrant substrates (i.e. cellulose, lignin or tannin-protein are fewer (168 but more phylogenetically-dispersed, occurring across 8 phyla and including Clostridiales, Sphingomonadalaes, Desulfovibrionales. Just over 6% of detected taxa, including many Burkholderiales increase in relative abundance with both labile and chemically recalcitrant substrates. Estimates of median rRNA copy number per genome of responding taxa demonstrate that these patterns are broadly consistent with bacterial growth strategies. Taken together, these data suggest that changes in availability of intrinsically labile substrates may result in predictable shifts in soil bacterial composition.
Full Text Available The gastrointestinal tract is populated by an array of microbial species that play an important role in metabolic and immune functions. The composition of microorganisms is influenced by the components of the host's diet and can impact health. In the present study, dietary enrichment of lowbush wild blueberries (LWB was examined to determine their effect on colon microbial composition and their potential in promoting gut health. The microbial composition and functional potential of the colon microbiota from Sprague Dawley rats fed control diets (AIN93 and LWB-enriched diets (AIN93+8% LWB powder substituting for dextrose for 6 weeks were assessed using Illumina shotgun sequencing and bioinformatics tools. Our analysis revealed an alteration in the relative abundance of 3 phyla and 22 genera as representing approximately 14 and 8% of all phyla and genera identified, respectively. The LWB-enriched diet resulted in a significant reduction in the relative abundance of the genera Lactobacillus and Enterococcus. In addition, hierarchal analysis revealed a significant increase in the relative abundance of the phylum Actinobacteria, the order Actinomycetales, and several novel genera under the family Bifidobacteriaceae and Coriobacteriaceae, in the LWB group. Functional annotation of the shotgun sequences suggested that approximately 9% of the 4709 Kyoto Encyclopaedia of Gene and Genome (KEGG hits identified were impacted by the LWB-diet. Open Reading Frames (ORFs assigned to KEGG category xenobiotics biodegradation and metabolism were significantly greater in the LWB-enriched diet compared to the control and included the pathway for benzoate degradation [PATH:ko00362] and glycosaminoglycan degradation [PATH:ko00531]. Moreover, the number of ORFs assigned to the bacterial invasion of epithelial cells [PATH:ko05100] pathway was approximately 8 fold lower in the LWB group compared to controls. This study demonstrated that LWBs have the potential to promote
Lacombe, Alison; Li, Robert W; Klimis-Zacas, Dorothy; Kristo, Aleksandra S; Tadepalli, Shravani; Krauss, Emily; Young, Ryan; Wu, Vivian C H
The gastrointestinal tract is populated by an array of microbial species that play an important role in metabolic and immune functions. The composition of microorganisms is influenced by the components of the host's diet and can impact health. In the present study, dietary enrichment of lowbush wild blueberries (LWB) was examined to determine their effect on colon microbial composition and their potential in promoting gut health. The microbial composition and functional potential of the colon microbiota from Sprague Dawley rats fed control diets (AIN93) and LWB-enriched diets (AIN93+8% LWB powder substituting for dextrose) for 6 weeks were assessed using Illumina shotgun sequencing and bioinformatics tools. Our analysis revealed an alteration in the relative abundance of 3 phyla and 22 genera as representing approximately 14 and 8% of all phyla and genera identified, respectively. The LWB-enriched diet resulted in a significant reduction in the relative abundance of the genera Lactobacillus and Enterococcus. In addition, hierarchal analysis revealed a significant increase in the relative abundance of the phylum Actinobacteria, the order Actinomycetales, and several novel genera under the family Bifidobacteriaceae and Coriobacteriaceae, in the LWB group. Functional annotation of the shotgun sequences suggested that approximately 9% of the 4709 Kyoto Encyclopaedia of Gene and Genome (KEGG) hits identified were impacted by the LWB-diet. Open Reading Frames (ORFs) assigned to KEGG category xenobiotics biodegradation and metabolism were significantly greater in the LWB-enriched diet compared to the control and included the pathway for benzoate degradation [PATH:ko00362] and glycosaminoglycan degradation [PATH:ko00531]. Moreover, the number of ORFs assigned to the bacterial invasion of epithelial cells [PATH:ko05100] pathway was approximately 8 fold lower in the LWB group compared to controls. This study demonstrated that LWBs have the potential to promote gut health and
Hazel A Barton
Full Text Available The majority of caves are formed within limestone rock and hence our understanding of cave microbiology comes from carbonate-buffered systems. In this paper, we describe the microbial diversity of Roraima Sur Cave, an orthoquartzite (SiO4 cave within Roraima Tepui, Venezuela. The cave contains a high level of microbial activity when compared with other cave systems, as determined by an ATP-based luminescence assay and cell counting. Molecular phylogenetic analysis of microbial diversity within the cave demonstrate the dominance of Actinomycetales and Alphaproteobacteria in endolithic bacterial communities close to the entrance, while communities from deeper in the cave are dominated (82-84% by a unique clade of Ktedonobacterales within the Chloroflexi. While members of this phylum are commonly found in caves, this is the first identification of members of the Class Ktedonobacterales. An assessment of archaeal species demonstrates the dominance of phylotypes from the Thaumarchaeota Group I.1c (100%, which have previously been associated with acidic environments. While the Thaumarchaeota have been seen in numerous cave systems, the dominance of Group I.1c in Roraima Sur Cave is unique and a departure from the traditional archaeal community structure. Geochemical analysis of the cave environment suggests that water entering the cave, rather than the nutrient-limited orthoquartzite rock, provides the carbon and energy necessary for microbial community growth and subsistence, while the poor buffering capacity of quartzite or the low pH of the environment may be selecting for this unusual community structure. Together these data suggest that pH, imparted by the geochemistry of the host rock, can play as important a role in niche-differentiation in caves as in other environmental systems.
La Duc, M. T.; Chen, F.; Baker, A.; Koukol, R. C.; Kern, R. G.; Venkateswaran, K. J.
Sampling the surfaces of both spacecraft and their clean-room assembly facilities is crucial in monitoring the microbial burden associated with these pseudo-sterile, oligotrophic environments. Here, we present the results of a study in which several surface samples, retrieved from both the Mars Odyssey Spacecraft and the Kennedy Space Center (KSC) Spacecraft Assembly and Encapsulation Facility II (SAEF-II), were processed and evaluated by both molecular and traditional culture-based methods for microbial diversity. The findings of this study improve our current understanding of the microbial community structure, diversity, and dispersal in a spacecraft assembly facility, as well as physically associated with co-located spacecraft. Surfaces of 25 cm2 (spacecraft) or 0.4 m2 (SAEF-II) were swabbed or wiped, respectively, and were examined for total heterotrophic aerobes and spore-formers. Samples were further subjected to nucleic acid extraction, and 16S rDNA fragments were PCR amplified with eubacterial biased universal primers and cloned. Approximately 30 isolates grown by traditional culture-based techniques were included for 16S rDNA sequencing. For the most part, the population dynamics remained consistent when compared between the spacecraft and assembly facility libraries. Predominant microbes, as indicated by molecular methods, included members of the genera Variovorax and Aquaspirillum. Members of the Mesorhizobium, Bradyrhizobium, Enterococcus, Ralstonia, and Bacillus genera were also found to span the various libraries but in less abundance. Traditional culture-based techniques validated the presence of Bacillus and Ralstonia, while illuminating a larger diversity in revealing the presence of Staphylococcus, Comamonas, Microbacterium, and Actinomycetales. The bulk of these findings make sense, since species of Ralstonia, Rhizobium, Variovorax, and Bacillus are known to frequently inhabit rhizospheric environments, like that surrounding the KSC facility, and
Full Text Available Abstract Background The ectoparasitic mite Varroa destructor has emerged as the primary pest of domestic honey bees (Apis mellifera. Here we present an initial survey of the V. destructor genome carried out to advance our understanding of Varroa biology and to identify new avenues for mite control. This sequence survey provides immediate resources for molecular and population-genetic analyses of Varroa-Apis interactions and defines the challenges ahead for a comprehensive Varroa genome project. Results The genome size was estimated by flow cytometry to be 565 Mbp, larger than most sequenced insects but modest relative to some other Acari. Genomic DNA pooled from ~1,000 mites was sequenced to 4.3× coverage with 454 pyrosequencing. The 2.4 Gbp of sequencing reads were assembled into 184,094 contigs with an N50 of 2,262 bp, totaling 294 Mbp of sequence after filtering. Genic sequences with homology to other eukaryotic genomes were identified on 13,031 of these contigs, totaling 31.3 Mbp. Alignment of protein sequence blocks conserved among V. destructor and four other arthropod genomes indicated a higher level of sequence divergence within this mite lineage relative to the tick Ixodes scapularis. A number of microbes potentially associated with V. destructor were identified in the sequence survey, including ~300 Kbp of sequence deriving from one or more bacterial species of the Actinomycetales. The presence of this bacterium was confirmed in individual mites by PCR assay, but varied significantly by age and sex of mites. Fragments of a novel virus related to the Baculoviridae were also identified in the survey. The rate of single nucleotide polymorphisms (SNPs in the pooled mites was estimated to be 6.2 × 10-5per bp, a low rate consistent with the historical demography and life history of the species. Conclusions This survey has provided general tools for the research community and novel directions for investigating the biology and control of
Navarrete, Acacio Aparecido; Diniz, Tatiana Rosa; Braga, Lucas Palma Perez; Silva, Genivaldo Gueiros Zacarias; Franchini, Julio Cezar; Rossetto, Raffaella; Edwards, Robert Alan; Tsai, Siu Mui
This study focused on the effects of organic and inorganic amendments and straw retention on the microbial biomass (MB) and taxonomic groups of bacteria in sugarcane-cultivated soils in a greenhouse mesocosm experiment monitored for gas emissions and chemical factors. The experiment consisted of combinations of synthetic nitrogen (N), vinasse (V; a liquid waste from ethanol production), and sugarcane-straw blankets. Increases in CO2-C and N2O-N emissions were identified shortly after the addition of both N and V to the soils, thus increasing MB nitrogen (MB-N) and decreasing MB carbon (MB-C) in the N+V-amended soils and altering soil chemical factors that were correlated with the MB. Across 57 soil metagenomic datasets, Actinobacteria (31.5%), Planctomycetes (12.3%), Deltaproteobacteria (12.3%), Alphaproteobacteria (12.0%) and Betaproteobacteria (11.1%) were the most dominant bacterial groups during the experiment. Differences in relative abundance of metagenomic sequences were mainly revealed for Acidobacteria, Actinobacteria, Gammaproteobacteria and Verrucomicrobia with regard to N+V fertilization and straw retention. Differential abundances in bacterial groups were confirmed using 16S rRNA gene-targeted phylum-specific primers for real-time PCR analysis in all soil samples, whose results were in accordance with sequence data, except for Gammaproteobacteria. Actinobacteria were more responsive to straw retention with Rubrobacterales, Bifidobacteriales and Actinomycetales related to the chemical factors of N+V-amended soils. Acidobacteria subgroup 7 and Opitutae, a verrucomicrobial class, were related to the chemical factors of soils without straw retention as a surface blanket. Taken together, the results showed that MB-C and MB-N responded to changes in soil chemical factors and CO2-C and N2O-N emissions, especially for N+V-amended soils. The results also indicated that several taxonomic groups of bacteria, such as Acidobacteria, Actinobacteria and
Salvetti, Elisa; Campanaro, Stefano; Campedelli, Ilenia; Fracchetti, Fabio; Gobbi, Alex; Tornielli, Giovanni Battista; Torriani, Sandra; Felis, Giovanna E
included representatives of genera Erwinia, Pantoea, Pseudomonas, Clostridium, Paenibacillus, and of orders Lactobacillales and Actinomycetales. These results provide insights into the microbial consortium of Corvina withered berries and reveal relevant variations attributable to post-harvest withering conditions, underling how WMS could open novel perspectives in the knowledge and management of the withering process of Corvina, with an impact on the winemaking of important Italian wines. PMID:27445999
Salvetti, Elisa; Campanaro, Stefano; Campedelli, Ilenia; Fracchetti, Fabio; Gobbi, Alex; Tornielli, Giovanni Battista; Torriani, Sandra; Felis, Giovanna E.
included representatives of genera Erwinia, Pantoea, Pseudomonas, Clostridium, Paenibacillus, and of orders Lactobacillales and Actinomycetales. These results provide insights into the microbial consortium of Corvina withered berries and reveal relevant variations attributable to post-harvest withering conditions, underling how WMS could open novel perspectives in the knowledge and management of the withering process of Corvina, with an impact on the winemaking of important Italian wines. PMID:27445999
Sinha, Krishna Murari; Unciuleac, Mihaela-Carmen; Glickman, Michael S; Shuman, Stewart
The resection of DNA double-strand breaks (DSBs) in bacteria is a motor-driven process performed by a multisubunit helicase-nuclease complex: either an Escherichia coli-type RecBCD enzyme or a Bacillus-type AddAB enzyme. Here we identify mycobacterial AdnAB as the founder of a new family of heterodimeric helicase-nucleases with distinctive properties. The AdnA and AdnB subunits are each composed of an N-terminal UvrD-like motor domain and a C-terminal nuclease module. The AdnAB ATPase is triggered by dsDNA with free ends and the energy of ATP hydrolysis is coupled to DSB end resection by the AdnAB nuclease. The mycobacterial nonhomologous end-joining (NHEJ) protein Ku protects DSBs from resection by AdnAB. We find that AdnAB incises ssDNA by measuring the distance from the free 5' end to dictate the sites of cleavage, which are predominantly 5 or 6 nucleotides (nt) from the 5' end. The "molecular ruler" of AdnAB is regulated by ATP, which elicits an increase in ssDNA cleavage rate and a distal displacement of the cleavage sites 16-17 nt from the 5' terminus. AdnAB is a dual nuclease with a clear division of labor between the subunits. Mutations in the nuclease active site of the AdnB subunit ablate the ATP-inducible cleavages; the corresponding changes in AdnA abolish ATP-independent cleavage. Complete suppression of DSB end resection requires simultaneous mutation of both subunit nucleases. The nuclease-null AdnAB is a helicase that unwinds linear plasmid DNA without degrading the displaced single strands. Mutations of the phosphohydrolase active site of the AdnB subunit ablate DNA-dependent ATPase activity, DSB end resection, and ATP-inducible ssDNA cleavage; the equivalent mutations of the AdnA subunit have comparatively little effect. AdnAB is a novel signature of the Actinomycetales taxon. Mycobacteria are exceptional in that they encode both AdnAB and RecBCD, suggesting the existence of alternative end-resecting motor-nuclease complexes. PMID:19470566
Amin, Rafat; Franz-Wachtel, Mirita; Tiffert, Yvonne; Heberer, Martin; Meky, Mohamed; Ahmed, Yousra; Matthews, Arne; Krysenko, Sergii; Jakobi, Marco; Hinder, Markus; Moore, Jane; Okoniewski, Nicole; Maček, Boris; Wohlleben, Wolfgang; Bera, Agnieszka
Soil-dwelling Streptomyces bacteria such as S.coelicolor have to constantly adapt to the nitrogen (N) availability in their habitat. Thus, strict transcriptional and post-translational control of the N-assimilation is fundamental for survival of this species. GlnR is a global response regulator that controls transcription of the genes related to the N-assimilation in S. coelicolor and other members of the Actinomycetales. GlnR represents an atypical orphan response regulator that is not activated by the phosphorylation of the conserved aspartate residue (Asp 50). We have applied transcriptional analysis, LC-MS/MS analysis and electrophoretic mobility shift assays (EMSAs) to understand the regulation of GlnR in S. coelicolor M145. The expression of glnR and GlnR-target genes was revisited under four different N-defined conditions and a complex N-rich condition. Although, the expression of selected GlnR-target genes was strongly responsive to changing N-concentrations, the glnR expression itself was independent of the N-availability. Using LC-MS/MSanalysis we demonstrated that GlnR was post-translationally modified. The post-translational modifications of GlnR comprise phosphorylation of the serine/threonine residues and acetylation of lysine residues. In the complex N-rich medium GlnR was phosphorylated on six serine/threonine residues and acetylated on one lysine residue. Under defined N-excess conditions only two phosphorylated residues were detected whereas under defined N-limiting conditions no phosphorylation was observed. GlnR phosphorylation is thus clearly correlated with N-rich conditions. Furthermore, GlnR was acetylated on four lysine residues independently of the N-concentration in the defined media and on only one lysine residue in the complex N-rich medium. Using EMSAs we demonstrated that phosphorylation inhibited the binding of GlnR to its targets genes, whereas acetylation had little influence on the formation of GlnR-DNA complex. This study clearly
Fouts Derrick E
Full Text Available Abstract Background Clinical dogma is that healthy urine is sterile and the presence of bacteria with an inflammatory response is indicative of urinary tract infection (UTI. Asymptomatic bacteriuria (ABU represents the state in which bacteria are present but the inflammatory response is negligible. Differentiating ABU from UTI is diagnostically challenging, but critical because overtreatment of ABU can perpetuate antimicrobial resistance while undertreatment of UTI can result in increased morbidity and mortality. In this study, we describe key characteristics of the healthy and ABU urine microbiomes utilizing 16S rRNA gene (16S rDNA sequencing and metaproteomics, with the future goal of utilizing this information to personalize the treatment of UTI based on key individual characteristics. Methods A cross-sectional study of 26 healthy controls and 27 healthy subjects at risk for ABU due to spinal cord injury-related neuropathic bladder (NB was conducted. Of the 27 subjects with NB, 8 voided normally, 8 utilized intermittent catheterization, and 11 utilized indwelling Foley urethral catheterization for bladder drainage. Urine was obtained by clean catch in voiders, or directly from the catheter in subjects utilizing catheters. Urinalysis, urine culture and 16S rDNA sequencing were performed on all samples, with metaproteomic analysis performed on a subsample. Results A total of 589454 quality-filtered 16S rDNA sequence reads were processed through a NextGen 16S rDNA analysis pipeline. Urine microbiomes differ by normal bladder function vs. NB, gender, type of bladder catheter utilized, and duration of NB. The top ten bacterial taxa showing the most relative abundance and change among samples were Lactobacillales, Enterobacteriales, Actinomycetales, Bacillales, Clostridiales, Bacteroidales, Burkholderiales, Pseudomonadales, Bifidobacteriales and Coriobacteriales. Metaproteomics confirmed the 16S rDNA results, and functional human protein
two samples, and included representatives of genera Erwinia, Pantoea, Pseudomonas, Clostridium, Paenibacillus, and of orders Lactobacillales and Actinomycetales.These results provide insights into the microbial consortium of Corvina withered berries and reveal relevant variations attributable to post-harvest withering conditions, underling how WMS could open novel perspectives in the knowledge and management of the withering process of Corvina, with an impact on the winemaking of important Italian wines.