Actinomycete

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Alan T Bull - One of the best experts on this subject based on the ideXlab platform.

  • Taxonomy and biotransformation activities of some deep-sea Actinomycetes
    Extremophiles, 1998
    Co-Authors: Joy A. Colquhoun, Jin Tamaoka, Spencer C. Heald, Lina Li, Chiaki Kato, Koki Horikoshi, Alan T Bull
    Abstract:

    Deep-sea soft sediments from trench systems and depths in the northwestern Pacific Ocean ranging from less than 300 to 10,897 m in depth have been analyzed for three target genera of Actinomycetes: Micromonospora, Rhodococcus, and Streptomyces. Only culturable strains, recovered at atmospheric pressure on selective isolation media, have been examined to date. Maximum recoveries of culturable bacteria were greater that 10(7)/ml wet g sediment, but Actinomycetes comprised a small proportion of this population (usually less than 1%). The target Actinomycetes were isolated at all depths except from the Mariana Trench sediments. Actinomycete colonies were defined initially on the basis of colony morphologies, and preliminary identification then was made by chemotaxonomic tests. Pyrolysis mass spectrometry (PyMS) of deep-sea mycolic acid-containing Actinomycetes gave excellent correspondence with numerical (phenetic) taxonomic analyses and subsequently was adopted as a rapid procedure for assessing taxonomic diversity. PyMS analysis enabled several clusters of deep-sea rhodococci to be distinguished that are quite distinct from all type strains. 16S rRNA gene sequence analysis has revealed that several of these marine rhodococci have sequences that are very similar to certain terrestrial species of Rhodococcus and to Dietzia. There is evidence for the intrusion of terrestrial runoff into these deep trench systems, and the inconsistency of the phenotypic and molecular taxonomies may reflect recent speciatiion events in Actinomycetes under the high-pressure conditions of the deep sea. The results of DNA-DNA pairing experiments point to the novelty of Rhodococcus strains recovered from hadal depths in the Izu Bonin Trench. Biotransformation studies of deep-sea bacteria have focused on nitrile compounds. Nitrile-metabolizing bacteria, closely related to rhodococci, have been isolated that grow well at low temperature, high salt concentrations, and high pressures, suggesting that they are of marine origin or have adapted to the deep-sea environment.

Paul R. Jensen - One of the best experts on this subject based on the ideXlab platform.

  • hybrid isoprenoid secondary metabolite production in terrestrial and marine Actinomycetes
    Current Opinion in Biotechnology, 2010
    Co-Authors: Kelley A Gallagher, William Fenical, Paul R. Jensen
    Abstract:

    Terpenoids are among the most ubiquitous and diverse secondary metabolites observed in nature. Although Actinomycete bacteria are one of the primary sources of microbially derived secondary metabolites, they rarely produce compounds in this biosynthetic class. The terpenoid secondary metabolites that have been discovered from Actinomycetes are often in the form of biosynthetic hybrids called hybrid isoprenoids (HIs). HIs include significant structural diversity and biological activity and thus are important targets for natural product discovery. Recent screening of marine Actinomycetes has led to the discovery of a new lineage that is enriched in the production of biologically active HI secondary metabolites. These strains represent a promising resource for natural product discovery and provide unique opportunities to study the evolutionary history and ecological functions of an unusual group of secondary metabolites.

  • nitropyrrolins a e cytotoxic farnesyl α nitropyrroles from a marine derived bacterium within the Actinomycete family streptomycetaceae
    Journal of Natural Products, 2010
    Co-Authors: Hak Cheol Kwon, Paul R. Jensen, Ana Paula D M Espindola, Jinsoo Park, Alejandra Prietodavo, Mickea Rose, William Fenical
    Abstract:

    Five new farnesyl-α-nitropyrroles, nitropyrrolins A–E (1–5), were isolated from the saline culture of the marine Actinomycete strain CNQ-509. This strain belongs to the “MAR4” group of marine Actinomycetes, which have been demonstrated to be a rich source of hybrid isoprenoid secondary metabolites. The structures of the nitropyrrolins are composed of α-nitropyrroles with functionalized farnesyl groups at the C-4 position. These compounds are the first examples of naturally-occurring terpenyl-α-nitropyrroles. Chemical modifications, including one-step acetonide formation from an epoxide, and application of the modified Mosher method, provided the full stereostructures and absolute configurations of these compounds. Several of the nitropyrrolins, nitropyrrolin D in particular, are cytotoxic toward HCT-116 human colon carcinoma cells, but show weak to little antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA).

  • culturable marine Actinomycete diversity from tropical pacific ocean sediments
    Environmental Microbiology, 2005
    Co-Authors: Paul R. Jensen, Tracy J Mincer, Erin A Gontang, Chrisy Mafnas, William Fenical
    Abstract:

    Author(s): Jensen, Paul R; Gontang, Erin; Mafnas, Chrisy; Mincer, Tracy J; Fenical, William | Abstract: Actinomycetes were cultivated using a variety of media and selective isolation techniques from 275 marine samples collected around the island of Guam. In total, 6425 Actinomycete colonies were observed and 983 (15%) of these, representing the range of morphological diversity observed from each sample, were obtained in pure culture. The majority of the strains isolated (58%) required seawater for growth indicating a high degree of marine adaptation. The dominant Actinomycete recovered (568 strains) belonged to the seawater-requiring marine taxon 'Salinospora', a new genus within the family Micromonosporaceae. A formal description of this taxon has been accepted for publication (Maldonado et al., 2005) and includes a revision of the generic epithet to Salinispora gen. nov. Members of two major new clades related to Streptomyces spp., tentatively called MAR2 and MAR3, were cultivated and appear to represent new genera within the Streptomycetaceae. In total, five new marine phylotypes, including two within the Thermomonosporaceae that appear to represent new taxa, were obtained in culture. These results support the existence of taxonomically diverse populations of phylogenetically distinct Actinomycetes residing in the marine environment. These bacteria can be readily cultured using low nutrient media and represent an unexplored resource for pharmaceutical drug discovery.

  • Marine Actinomycete diversity and natural product discovery
    Antonie van Leeuwenhoek International Journal of General and Molecular Microbiology, 2005
    Co-Authors: Paul R. Jensen, Tracy J Mincer, Philip G Williams, William Fenical
    Abstract:

    Microbial natural products remain an important resource for drug discovery yet the microorganisms inhabiting the world's oceans have largely been overlooked in this regard. The recent discovery of novel secondary metabolites from taxonomically unique populations of marine Actinomycetes suggests that these bacteria add an important new dimension to microbial natural product research. Continued efforts to characterize marine Actinomycete diversity and how adaptations to the marine environment affect secondary metabolite production will create a better understanding of the potential utility of these bacteria as a source of useful products for biotechnology.

Joy A. Colquhoun - One of the best experts on this subject based on the ideXlab platform.

  • Taxonomy and biotransformation activities of some deep-sea Actinomycetes
    Extremophiles, 1998
    Co-Authors: Joy A. Colquhoun, Jin Tamaoka, Spencer C. Heald, Lina Li, Chiaki Kato, Koki Horikoshi, Alan T Bull
    Abstract:

    Deep-sea soft sediments from trench systems and depths in the northwestern Pacific Ocean ranging from less than 300 to 10,897 m in depth have been analyzed for three target genera of Actinomycetes: Micromonospora, Rhodococcus, and Streptomyces. Only culturable strains, recovered at atmospheric pressure on selective isolation media, have been examined to date. Maximum recoveries of culturable bacteria were greater that 10(7)/ml wet g sediment, but Actinomycetes comprised a small proportion of this population (usually less than 1%). The target Actinomycetes were isolated at all depths except from the Mariana Trench sediments. Actinomycete colonies were defined initially on the basis of colony morphologies, and preliminary identification then was made by chemotaxonomic tests. Pyrolysis mass spectrometry (PyMS) of deep-sea mycolic acid-containing Actinomycetes gave excellent correspondence with numerical (phenetic) taxonomic analyses and subsequently was adopted as a rapid procedure for assessing taxonomic diversity. PyMS analysis enabled several clusters of deep-sea rhodococci to be distinguished that are quite distinct from all type strains. 16S rRNA gene sequence analysis has revealed that several of these marine rhodococci have sequences that are very similar to certain terrestrial species of Rhodococcus and to Dietzia. There is evidence for the intrusion of terrestrial runoff into these deep trench systems, and the inconsistency of the phenotypic and molecular taxonomies may reflect recent speciatiion events in Actinomycetes under the high-pressure conditions of the deep sea. The results of DNA-DNA pairing experiments point to the novelty of Rhodococcus strains recovered from hadal depths in the Izu Bonin Trench. Biotransformation studies of deep-sea bacteria have focused on nitrile compounds. Nitrile-metabolizing bacteria, closely related to rhodococci, have been isolated that grow well at low temperature, high salt concentrations, and high pressures, suggesting that they are of marine origin or have adapted to the deep-sea environment.

Kozo Ochi - One of the best experts on this subject based on the ideXlab platform.

  • Phylogenetic Analysis of Mycolic Acid-Containing Wall-Chemotype IV Actinomycetes and Allied Taxa by Partial Sequencing of Ribosomal Protein AT-L30
    International Journal of Systematic and Evolutionary Microbiology, 1995
    Co-Authors: Kozo Ochi
    Abstract:

    The phylogenetic relationships among 30 mycolic acid-containing wall chemotype IV Actinomycete strains and 12 strains belonging to allied taxa were examined by determining the amino acid sequences of the ribosomal AT-L30 proteins of these organisms. Sequencing 20 N-terminal amino acids of AT-L30 preparations revealed that the members of the genera containing mycolic acid-containing Actinomycetes form two clusters; the first cluster contains the genera Nocardia, Rhodococcus, Gordona, and Tsukamurella, and the second cluster contains the genera Corynebacterium and Mycobacterium. The genus Nocardia was placed in a clade containing the genus Rhodococcus. The data showed that Tsukamurella paurometabolum is closely related phylogenetically to the genus Gordona. The phylogenetic clusters identified were entirely consistent with the proposal of Goodfellow that the family Nocardiaceae should encompass the mycolate-containing, cell wall type IV Actinomycete genera Nocardia, Rhodococcus, Gordona, and Tsukamurella. The genera Actinomyces and Micrococcus exhibited AT-L30 amino acid sequence characteristics intermediate between those of Actinomycetes and those of typical eubacteria. The genera Nocardia, Gordona, Mycobacterium, Actinoplanes, and Micromonospora were each a taxon that consisted of phylogenetically coherent species. In contrast, the genera Rhodococcus and Corynebacterium are taxa that consist of phylogenetically distantly related species. In general, my results are consistent with previous 16S rRNA sequencing results, but significant differences were also found. My data, together with previous AT-L30 sequencing data, show that phylogenetic relationships among taxa can be determined by using markers other than the ribosomal gene sequences.

  • Phylogenetic Analysis of Mycolic Acid-Containing Actinomycetes and Allied Taxa by Partial of Ribosomal Protein AT-L30 Wall-Chemotype IV Sequencing
    1995
    Co-Authors: Kozo Ochi
    Abstract:

    The phylogenetic relationships among 30 mycolic acid-containing wall chemotype IV Actinomycete strains and 12 strains belonging to allied taxa were examined by determining the amino acid sequences of the ribosomal AT-L30 proteins of these organisms. Sequencing 20 N-terminal amino acids of AT-L30 preparations revealed that the members of the genera containing mycolic acid-containing Actinomycetes form two clusters; the first cluster contains the genera Nocardia, Rhodococcus, Gordona, and Tsukamurella, and the second cluster contains the genera Corynebacterium and Mycobacterium. The genus Nocardia was placed in a clade containing the genus Rhodococcus. The data showed that Tsukamurella paurometabolum is closely related phylogenetically to the genus Gordona. The phylogenetic clusters identified were entirely consistent with the proposal of Goodfellow that the family Nocardiaceae should encompass the mycolate-containing, cell wall type IV Actinomycete genera Nocardia, Rhodococcus, Gordona, and Tsukamurella. The genera Actinomyces and Micrococcus exhibited AT-UO amino acid sequence characteristics intermediate between those of Actinomycetes and those of typical eubacteria. The genera Nocardia, Gordona, Mycobacterium, Actinoplanes, and Micromonospora were each a taxon that consisted of phylogenetically coherent species. In contrast, the genera Rhodococcus and Corynebacterium are taxa that consist of phylogenetically distantly related species. In general, my results are consistent with previous 16s rRNA sequencing results, but significant differences were also found. My data, together with previous AT-L30 sequencing data, show that phylogenetic relationships among taxa can be determined by using markers other than the ribosomal gene sequences. Microorganisms containing mycolic acids in their cell walls have many properties in common (13) and form a recognizable suprageneric group (28,49,52). These organisms have chemotype IV walls (26) and can be assigned to the genera Coiynebacterium, Gordona, Mycobacterium, Nocardia , Rhodococcus, and Tsukamurella by using a combination of chemical and morphological markers (12). Nocardiae produce abundant or sparse aerial mycelia, but corynebacteria do not produce mycelia. Mycobacteria and rhodococci do not usually form aerial hyphae, with a few exceptions. The taxonomy of the Actinomycetes containing mycolic acids has undergone significant revisions based on data obtained by chemical, numerical, and molecular systematic methods; such revisions have occurred in the genera Rhodococcus (11-13, 15), Corynebacterium (27), Gordona (51), Tsukamurella (4), and Mycobacterium (17, 18, 46, 60). The genus Nocardia is the type genus of the family Nocardiaceae. The genus Gordona is characterized by the absence of mycelia and slight or strong acid fastness, and members of this genus have characteristics intermediate between those of the genus Nocardia and those of the genus Mycobactenurn (54). The taxonomy of the genus Gordona and the related genus Tsukamurella has been clarified by using chemical, molecular systematic, and numerical taxonomic methods (16). Traditionally, taxonomic studies have relied heavily on morphological characteristics, but numerical taxonomy and chemotaxonomic characteristics have played important roles in determining taxonomic relationships. DNA hybridization and 16s rRNA similarity data are also important, especially for determining phylogenetic relationships at both the generic level and the subgeneric level. Since 1989, Ochi and coworkers have developed a method for identifying and classifying Actinomycetes (30-32). This ap

William Fenical - One of the best experts on this subject based on the ideXlab platform.

  • hybrid isoprenoid secondary metabolite production in terrestrial and marine Actinomycetes
    Current Opinion in Biotechnology, 2010
    Co-Authors: Kelley A Gallagher, William Fenical, Paul R. Jensen
    Abstract:

    Terpenoids are among the most ubiquitous and diverse secondary metabolites observed in nature. Although Actinomycete bacteria are one of the primary sources of microbially derived secondary metabolites, they rarely produce compounds in this biosynthetic class. The terpenoid secondary metabolites that have been discovered from Actinomycetes are often in the form of biosynthetic hybrids called hybrid isoprenoids (HIs). HIs include significant structural diversity and biological activity and thus are important targets for natural product discovery. Recent screening of marine Actinomycetes has led to the discovery of a new lineage that is enriched in the production of biologically active HI secondary metabolites. These strains represent a promising resource for natural product discovery and provide unique opportunities to study the evolutionary history and ecological functions of an unusual group of secondary metabolites.

  • nitropyrrolins a e cytotoxic farnesyl α nitropyrroles from a marine derived bacterium within the Actinomycete family streptomycetaceae
    Journal of Natural Products, 2010
    Co-Authors: Hak Cheol Kwon, Paul R. Jensen, Ana Paula D M Espindola, Jinsoo Park, Alejandra Prietodavo, Mickea Rose, William Fenical
    Abstract:

    Five new farnesyl-α-nitropyrroles, nitropyrrolins A–E (1–5), were isolated from the saline culture of the marine Actinomycete strain CNQ-509. This strain belongs to the “MAR4” group of marine Actinomycetes, which have been demonstrated to be a rich source of hybrid isoprenoid secondary metabolites. The structures of the nitropyrrolins are composed of α-nitropyrroles with functionalized farnesyl groups at the C-4 position. These compounds are the first examples of naturally-occurring terpenyl-α-nitropyrroles. Chemical modifications, including one-step acetonide formation from an epoxide, and application of the modified Mosher method, provided the full stereostructures and absolute configurations of these compounds. Several of the nitropyrrolins, nitropyrrolin D in particular, are cytotoxic toward HCT-116 human colon carcinoma cells, but show weak to little antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA).

  • culturable marine Actinomycete diversity from tropical pacific ocean sediments
    Environmental Microbiology, 2005
    Co-Authors: Paul R. Jensen, Tracy J Mincer, Erin A Gontang, Chrisy Mafnas, William Fenical
    Abstract:

    Author(s): Jensen, Paul R; Gontang, Erin; Mafnas, Chrisy; Mincer, Tracy J; Fenical, William | Abstract: Actinomycetes were cultivated using a variety of media and selective isolation techniques from 275 marine samples collected around the island of Guam. In total, 6425 Actinomycete colonies were observed and 983 (15%) of these, representing the range of morphological diversity observed from each sample, were obtained in pure culture. The majority of the strains isolated (58%) required seawater for growth indicating a high degree of marine adaptation. The dominant Actinomycete recovered (568 strains) belonged to the seawater-requiring marine taxon 'Salinospora', a new genus within the family Micromonosporaceae. A formal description of this taxon has been accepted for publication (Maldonado et al., 2005) and includes a revision of the generic epithet to Salinispora gen. nov. Members of two major new clades related to Streptomyces spp., tentatively called MAR2 and MAR3, were cultivated and appear to represent new genera within the Streptomycetaceae. In total, five new marine phylotypes, including two within the Thermomonosporaceae that appear to represent new taxa, were obtained in culture. These results support the existence of taxonomically diverse populations of phylogenetically distinct Actinomycetes residing in the marine environment. These bacteria can be readily cultured using low nutrient media and represent an unexplored resource for pharmaceutical drug discovery.

  • Marine Actinomycete diversity and natural product discovery
    Antonie van Leeuwenhoek International Journal of General and Molecular Microbiology, 2005
    Co-Authors: Paul R. Jensen, Tracy J Mincer, Philip G Williams, William Fenical
    Abstract:

    Microbial natural products remain an important resource for drug discovery yet the microorganisms inhabiting the world's oceans have largely been overlooked in this regard. The recent discovery of novel secondary metabolites from taxonomically unique populations of marine Actinomycetes suggests that these bacteria add an important new dimension to microbial natural product research. Continued efforts to characterize marine Actinomycete diversity and how adaptations to the marine environment affect secondary metabolite production will create a better understanding of the potential utility of these bacteria as a source of useful products for biotechnology.