Micrococcus endophyticus sp. nov., isolated from surface-sterilized Aquilaria sinensis roots.
ABSTRACT A Gram-positive bacterial strain, designated YIM 56238(T), was isolated from plant roots (Aquilaria sinensis), and characterized by using a polyphasic approach. Strain YIM 56238(T) grew optimally at pH 7.0-8.0 and at 28 degrees C. Analysis of the 16S rRNA gene sequence of strain YIM 56238(T) indicated that it belongs to the genus Micrococcus. Chemotaxonomic data strongly supported the classification of this strain within the genus Micrococcus: the cell-wall peptidoglycan contained lysine, glutamic acid, alanine and glycine; the predominant menaquinones were MK-8(H(2)) (63.6 %) and MK-7(H(2)) (21.1 %); the phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unknown ninhydrin-negative phospholipid; and the major cellular fatty acids were iso-C(15 : 0) (30.95 %) and anteiso-C(15 : 0) (53.75 %). The G+C content of the genomic DNA was 72.9 mol%. A number of physiological features were found that clearly distinguished strain YIM 56238(T) from recognized species of the genus Micrococcus. DNA-DNA hybridization studies suggested that the novel strain represents a separate genomic species. On the basis of the data, therefore, strain YIM 56238(T) represents a novel species of the genus Micrococcus, for which the name Micrococcus endophyticus sp. nov. is proposed. The type strain is YIM 56238(T) (=DSM 17945(T)=KCTC 19156(T)).
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ABSTRACT: Micrococci are Gram-positive G + C-rich, nonmotile, nonspore-forming actinomycetous bacteria. Micrococcus comprises ten members, with Micrococcus luteus being the type species. Representatives of the genus play important roles in the biodegradation of xenobiotics, bioremediation processes, production of biotechnologically important enzymes or bioactive compounds, as test strains in biological assays for lysozyme and antibiotics, and as infective agents in immunocompromised humans. The first description of plasmids dates back approximately 28 years, when several extrachromosomal elements ranging in size from 1.5 to 30.2 kb were found in Micrococcus luteus. Up to the present, a number of circular plasmids conferring antibiotic resistance, the ability to degrade aromatic compounds, and osmotolerance are known, as well as cryptic elements with unidentified functions. Here, we review the Micrococcus extrachromosomal traits reported thus far including phages and the only quite recently described large linear extrachromosomal genetic elements, termed linear plasmids, which range in size from 75 kb (pJD12) to 110 kb (pLMA1) and which confer putative advantageous capabilities, such as antibiotic or heavy metal resistances (inferred from sequence analyses and curing experiments). The role of the extrachromosomal elements for the frequently proven ecological and biotechnological versatility of the genus will be addressed as well as their potential for the development and use as genetic tools.Applied Microbiology and Biotechnology 11/2012; · 3.69 Impact Factor
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ABSTRACT: A Gram-positive, yellow-pigmented, actinobacterial strain, DW152(T), was isolated from a dairy industry effluent treatment plant. 16S rRNA gene sequence analysis indicated that strain DW152(T) exhibited low similarity with many species with validly published names belonging to the genera Micrococcus and Arthrobacter. However, phenotypic properties including chemotaxonomic markers affiliated strain DW152(T) to the genus Micrococcus. Strain DW152(T) had ai-C(15:0) and i-C(15:0) as major cellular fatty acids, and MK-8(H(2)) as the major menaquinone. The cell-wall peptidoglycan of strain DW152(T) had l-lysine as the diagnostic amino acid and the type was A4α. The DNA G+C content of strain DW152(T) was 68.0 mol%. In 16S rRNA gene sequence analysis, strain DW152(T) exhibited significant similarity with Micrococcus terreus NBRC 104258(T), but the mean value of DNA-DNA relatedness between these strains was only 42.3%. Moreover, strain DW152(T) differed in biochemical and chemotaxonomic characteristics from M. terreus and other species of the genus Micrococcus. Based on the above differences, we conclude that strain DW152(T) should be treated as a novel species of the genus Micrococcus, for which the name Micrococcus lactis sp. nov. is proposed. The type strain of Micrococcus lactis sp. nov. is DW152(T) (=MTCC10523(T) =DSM 23694(T)).INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 01/2011; 61(Pt 12):2832-6. · 2.11 Impact Factor
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ABSTRACT: Endophytic actinobacteria, which exist in the inner tissues of living plants, have attracted increasing attention among taxonomists, ecologists, agronomists, chemists and evolutionary biologists. Numerous studies have indicated that these prolific actinobacteria appear to have a capacity to produce an impressive array of secondary metabolites exhibiting a wide variety of biological activity, such as antibiotics, antitumor and anti-infection agents, plant growth promoters and enzymes, and may contribute to their host plants by promoting growth and enhancing their ability of withstanding the environmental stresses. These microorganisms may represent an underexplored reservoir of novel species of potential interest in the discovery of novel lead compounds and for exploitation in pharmaceutical, agriculture and industry. This review focuses on new findings in the isolation methods, bio- and chemical diversity of endophytic actinobacteria and reveals the potential biotechnological application. The facing problems and strategies for biodiversity research and bioactive natural products producing are also discussed.Applied Microbiology and Biotechnology 10/2010; 89(3):457-73. · 3.69 Impact Factor