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Emerging Infectious Diseases 1997Rhodococcus equi and Arcanobacterium haemolyticum, formerly classified in the genus Corynebacterium, are members of the loosely defined taxon "coryneform" bacteria.... (Review)
Review
Rhodococcus equi and Arcanobacterium haemolyticum, formerly classified in the genus Corynebacterium, are members of the loosely defined taxon "coryneform" bacteria. Although they are the etiologic agents of distinct human infections, both organisms are frequently overlooked, which results in missed or delayed diagnoses. R. equi, long known as an important pathogen of immature horses, has become in the past three decades an opportunistic pathogen of severely immunosuppressed humans. Most cases are secondary to HIV infection. When specifically sought in throat swab cultures, A. haemolyticum is found responsible for 0.5% to 2.5% of bacterial pharyngitis, especially among adolescents. These two microorganisms represent a spectrum of disease in humans: from a mild, common illness to a rare life-threatening infection. Each organism elaborates lipid hydrolyzing enzymes (cholesterol oxidase by R. equi and sphingomyelinase D by A. haemolyticum) that are toxic to animals and humans and damaging to mammalian cell membranes. The participation of the cytotoxins in pathogenicity is discussed. Greater awareness of the properties of these two bacteria may promote faster, more accurate diagnoses and better clinical management.
Topics: Actinomycetales; Actinomycetales Infections; Humans; Rhodococcus equi
PubMed: 9204295
DOI: 10.3201/eid0302.970207 -
Marine Biotechnology (New York, N.Y.) Oct 2011Marine sponges and their associated bacteria have been proven to be a rich source of novel secondary metabolites with therapeutic usefulness in cancer, infection, and...
Marine sponges and their associated bacteria have been proven to be a rich source of novel secondary metabolites with therapeutic usefulness in cancer, infection, and autoimmunity. In this study, 79 strains belonging to 20 genera of the order Actinomycetales and seven strains belonging to two genera of the order Sphingomonadales were cultivated from 18 different Caribbean sponges and identified by 16S rRNA gene sequencing. Seven of these strains are likely to represent novel species. Crude extracts from selected strains were found to exhibit protease inhibition against cathepsins B and L, rhodesain, and falcipain-2 as well as immunomodulatory activities such as induction of cytokine release by human peripheral blood mononuclear cells. These results highlight the significance of marine sponge-associated bacteria to produce bioactive secondary metabolites with therapeutic potential in the treatment of infectious diseases and disorders of the immune system.
Topics: Actinomycetales; Alphaproteobacteria; Animals; Caribbean Region; Gene Expression Regulation, Bacterial; Immunologic Factors; Porifera; Protease Inhibitors; RNA, Bacterial; RNA, Ribosomal, 16S
PubMed: 21222136
DOI: 10.1007/s10126-010-9349-0 -
Biotechnology and Bioengineering Jul 2012Infection caused by methicillin-resistant Staphylococcus aureus (MRSA) is an increasing societal problem. Typically, glycopeptide antibiotics are used in the treatment...
Infection caused by methicillin-resistant Staphylococcus aureus (MRSA) is an increasing societal problem. Typically, glycopeptide antibiotics are used in the treatment of these infections. The most comprehensively studied glycopeptide antibiotic biosynthetic pathway is that of balhimycin biosynthesis in Amycolatopsis balhimycina. The balhimycin yield obtained by A. balhimycina is, however, low and there is therefore a need to improve balhimycin production. In this study, we performed genome sequencing, assembly and annotation analysis of A. balhimycina and further used these annotated data to reconstruct a genome-scale metabolic model for the organism. Here we generated an almost complete A. balhimycina genome sequence comprising 10,562,587 base pairs assembled into 2,153 contigs. The high GC-genome (∼ 69%) includes 8,585 open reading frames (ORFs). We used our integrative toolbox called SEQTOR for functional annotation and then integrated annotated data with biochemical and physiological information available for this organism to reconstruct a genome-scale metabolic model of A. balhimycina. The resulting metabolic model contains 583 ORFs as protein encoding genes (7% of the predicted 8,585 ORFs), 407 EC numbers, 647 metabolites and 1,363 metabolic reactions. During the analysis of the metabolic model, linear, quadratic and evolutionary programming algorithms using flux balance analysis (FBA), minimization of metabolic adjustment (MOMA), and OptGene, respectively were applied as well as phenotypic behavior and improved balhimycin production were simulated. The A. balhimycina model shows a good agreement between in silico data and experimental data and also identifies key reactions associated with increased balhimycin production. The reconstruction of the genome-scale metabolic model of A. balhimycina serves as a basis for physiological characterization. The model allows a rational design of engineering strategies for increasing balhimycin production in A. balhimycina and glycopeptide production in general.
Topics: Actinomycetales; Anti-Bacterial Agents; Computer Simulation; Genome, Bacterial; Metabolic Networks and Pathways; Models, Biological; Vancomycin
PubMed: 22252737
DOI: 10.1002/bit.24436 -
Journal of Clinical Microbiology Dec 1993
Comparative Study
Topics: Actinomyces; Actinomycetales; Fatty Acids; Humans; Species Specificity
PubMed: 8308138
DOI: 10.1128/jcm.31.12.3353-3354.1993 -
Journal of Applied Microbiology Nov 2010To develop an applicable vector system and a transformation method for the manipulation of Dietzia spp.
AIM
To develop an applicable vector system and a transformation method for the manipulation of Dietzia spp.
METHODS AND RESULTS
The pNV18 Nocardia-E. coli shuttle vector was tested and found to be a replicating plasmid in Dietzia sp. E1. With the use of pNV18, an electroporation method was optimized for the transformation of Dietzia sp. E1, and a transformation efficiency suitable for genetic manipulations was achieved (2·18×10(4) transformants μg(-1) DNA). The method was also applied for the transformation of Dietzia cinnamea, D. maris, D. natronolimnaea and D. psychralcaliphila.
CONCLUSIONS
The first applicable vectors and a simple electroporation protocol enabling the manipulation of several Dietzia spp. are presented.
SIGNIFICANCE AND IMPACT OF THE STUDY
Dietzia spp. have clinical, industrial and great environmental importance; however, the analysis of the Dietzia genus is currently hampered by the lack of manipulation techniques. The presented basic tools allow the genetic analysis of several Dietzia species, including the human disease-associated Dietzia maris.
Topics: Actinomycetales; Biotechnology; Culture Media; Electroporation; Genetic Techniques; Genetic Vectors; Plasmids
PubMed: 20666867
DOI: 10.1111/j.1365-2672.2010.04818.x -
Bacteriological Reviews Sep 1977
Review
Topics: Actinomycetales; Anti-Bacterial Agents; Bacteria; Fungi; Mutation; Species Specificity
PubMed: 334152
DOI: 10.1128/br.41.3.595-635.1977 -
Molecular Ecology Aug 2013The stability of mutualistic interactions is likely to be affected by the genetic diversity of symbionts that compete for the same functional niche. Fungus-growing...
The stability of mutualistic interactions is likely to be affected by the genetic diversity of symbionts that compete for the same functional niche. Fungus-growing (attine) ants have multiple complex symbioses and thus provide ample opportunities to address questions of symbiont specificity and diversity. Among the partners are Actinobacteria of the genus Pseudonocardia that are maintained on the ant cuticle to produce antibiotics, primarily against a fungal parasite of the mutualistic gardens. The symbiosis has been assumed to be a hallmark of evolutionary stability, but this notion has been challenged by culturing and sequencing data indicating an unpredictably high diversity. We used 454 pyrosequencing of 16S rRNA to estimate the diversity of the cuticular bacterial community of the leaf-cutting ant Acromyrmex echinatior and other fungus-growing ants from Gamboa, Panama. Both field and laboratory samples of the same colonies were collected, the latter after colonies had been kept under laboratory conditions for up to 10 years. We show that bacterial communities are highly colony-specific and stable over time. The majority of colonies (25/26) had a single dominant Pseudonocardia strain, and only two strains were found in the Gamboa population across 17 years, confirming an earlier study. The microbial community on newly hatched ants consisted almost exclusively of a single strain of Pseudonocardia while other Actinobacteria were identified on older, foraging ants in varying but usually much lower abundances. These findings are consistent with recent theory predicting that mixtures of antibiotic-producing bacteria can remain mutualistic when dominated by a single vertically transmitted and resource-demanding strain.
Topics: Actinomycetales; Animals; Ants; Genetic Variation; Panama; Phylogeny; Polymerase Chain Reaction; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Species Specificity; Symbiosis
PubMed: 23899369
DOI: 10.1111/mec.12380 -
Mathermycin, a Lantibiotic from the Marine Actinomycete Marinactinospora thermotolerans SCSIO 00652.Applied and Environmental Microbiology Aug 2017Lantibiotics are antimicrobial peptides belonging to the family of ribosomally synthesized and posttranslationally modified peptides (RiPPs) and feature thioether...
Lantibiotics are antimicrobial peptides belonging to the family of ribosomally synthesized and posttranslationally modified peptides (RiPPs) and feature thioether linkages in their structures. In this study, we identified the biosynthetic gene cluster of a cinnamycin analog, named mathermycin, from SCSIO 00652 and reconstituted its biosynthesis in and Key posttranslational modification enzymes of mathermycin were characterized. Mathermycin exhibited antimicrobial activity and therefore represents an example of cinnamycin-like lantibiotics from species. The discovery of new antimicrobial compounds that can be used as potential drugs is in urgent need due to increasing bacterial resistance to current antibiotics. Lantibiotics are important antimicrobial compounds that have found applications in both the clinic setting and food industry. We report here the discovery of a new lantibiotic, mathermycin, from a marine-derived strain and elucidation of its biosynthesis. We also demonstrate that mathermycin possesses antimicrobial activity toward a strain.
Topics: Actinomycetales; Amino Acid Sequence; Bacillus subtilis; Bacterial Proteins; Bacteriocins; Biosynthetic Pathways; Peptide Mapping; Seawater
PubMed: 28576760
DOI: 10.1128/AEM.00926-17 -
Nature Communications Mar 2016Prenylation reactions play crucial roles in controlling the activities of biomolecules. Bacterial prenyltransferases, TleC from Streptomyces blastmyceticus and MpnD from...
Prenylation reactions play crucial roles in controlling the activities of biomolecules. Bacterial prenyltransferases, TleC from Streptomyces blastmyceticus and MpnD from Marinactinospora thermotolerans, catalyse the 'reverse' prenylation of (-)-indolactam V at the C-7 position of the indole ring with geranyl pyrophosphate or dimethylallyl pyrophosphate, to produce lyngbyatoxin or pendolmycin, respectively. Using in vitro analyses, here we show that both TleC and MpnD exhibit relaxed substrate specificities and accept various chain lengths (C5-C25) of the prenyl donors. Comparisons of the crystal structures and their ternary complexes with (-)-indolactam V and dimethylallyl S-thiophosphate revealed the intimate structural details of the enzyme-catalysed 'reverse' prenylation reactions and identified the active-site residues governing the selection of the substrates. Furthermore, structure-based enzyme engineering successfully altered the preference for the prenyl chain length of the substrates, as well as the regio- and stereo-selectivities of the prenylation reactions, to produce a series of unnatural novel indolactams.
Topics: Actinomycetales; Bacterial Proteins; Dimethylallyltranstransferase; Indoles; Lactams; Molecular Structure; Prenylation; Protein Engineering; Streptomyces; Substrate Specificity
PubMed: 26952246
DOI: 10.1038/ncomms10849 -
Applied and Environmental Microbiology Nov 2010We cloned and purified the major family 10 xylanase (Xyn10A) from Acidothermus cellulolyticus 11B. Xyn10A was active on oat spelt and birchwood xylans between 60°C and...
We cloned and purified the major family 10 xylanase (Xyn10A) from Acidothermus cellulolyticus 11B. Xyn10A was active on oat spelt and birchwood xylans between 60°C and 100°C and between pH 4 and pH 8. The optimal activity was at 90°C and pH 6; specific activity and K(m) for oat spelt xylan were 350 μmol xylose produced min⁻¹ mg of protein⁻¹ and 0.53 mg ml⁻¹, respectively. Based on xylan cleavage patterns, Xyn10A is an endoxylanase, and its half-life at 90°C was approximately 1.5 h in the presence of xylan.
Topics: Actinomycetales; Cloning, Molecular; DNA, Bacterial; Endo-1,4-beta Xylanases; Genes, Bacterial; Half-Life; Hot Temperature; Hydrogen-Ion Concentration; Xylans
PubMed: 20851989
DOI: 10.1128/AEM.01326-10