Marinimicrococcus flavescens gen. nov., sp. nov., a new member of the family Geminicoccaceae, isolated from a marine sediment of the South China Sea.

A Gram-stain-negative, catalase-positive and oxidase-positive, nonmotile, aerobic, light yellow, spherical-shaped bacterial strain with no flagella, designated strain YIM 152171T, was isolated from sediment of the South China Sea. Colonies were smooth and convex, light yellow and circular, and 1.0-1.5×1.0-1.5 µm in cell diameter after 7 days of incubation at 28°C on YIM38 media supplemented with sea salt. Colonies could grow at 20-45°C (optimum 28-35°C) and pH 6.0-11.0 (optimum, pH 7.0-9.0), and they could proliferate in the salinity range of 0-6.0 % (w/v) NaCl. The major cellular fatty acids were summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c), C18 : 1 ω7c 11-methyl, C16 : 0, C16 : 1 ω11c, C16 : 1 ω5c, C17 : 1 ω6c and C18 : 1 ω5c. The respiratory quinone was ubiquinone 10, and the polar lipid profile included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol mannoside, one unidentified phospholipid and one unidentified aminolipid. Phylogenetic analyses based on the 16S rRNA gene sequences placed strain YIM 152171T within the order Rhodospirillales in a distinct lineage that also included the genus Geminicoccus. The 16S rRNA gene sequence similarities of YIM 152171T to those of Arboricoccus pini, Geminicoccus roseus and Constrictibacter antarcticus were 92.17, 89.25 and 88.91 %, respectively. The assembled draft genome of strain YIM 152171T had 136 contigs with an N50 value of 134704 nt, a total length of 3 001 346 bp and a G+C content of 70.27 mol%. The phylogenetic, phenotypic and chemotaxonomic data showed that strain YIM 152171T (=MCCC 1K08488T=KCTC 92884T) represents a type of novel species and genus for which we propose the name Marinimicrococcus gen. nov., sp. nov.

Methods for the study of endophytic microorganisms from traditional Chinese medicine plants.

Plant endophytes are very numerous and widely distributed in nature, their relationships being described as a balanced symbiotic continuum ranging from mutualism through commensalism to parasitism during a long period of coevolution. Traditional Chinese medicines have played a very important role in disease treatment in China and other Asian countries. Investigations show that these medicinal plants harbor endophytes with different kinds of ecological functions, and some of them have potential to produce bioactive small-molecule compounds. This chapter will focus on the selective isolation methods, the diversity of some endophytes (actinobacteria and fungi) isolated from Traditional Chinese Medicine (TCM) plants, and the bioactive compounds from selected endophytic actinobacteria reported in the past 3 years.

Isolation, diversity, and antimicrobial activity of rare actinobacteria from medicinal plants of tropical rain forests in Xishuangbanna, China.

Endophytic actinobacteria are relatively unexplored as potential sources of novel species and novel natural products for medical and commercial exploitation. Xishuangbanna is recognized throughout the world for its diverse flora, especially the rain forest plants, many of which have indigenous pharmaceutical histories. However, little is known about the endophytic actinobacteria of this tropical area. In this work, we studied the diversity of actinobacteria isolated from medicinal plants collected from tropical rain forests in Xishuangbanna. By the use of different selective isolation media and methods, a total of 2,174 actinobacteria were isolated. Forty-six isolates were selected on the basis of their morphologies on different media and were further characterized by 16S rRNA gene sequencing. The results showed an unexpected level of diversity, with 32 different genera. To our knowledge, this is the first report describing the isolation of Saccharopolyspora, Dietzia, Blastococcus, Dactylosporangium, Promicromonospora, Oerskovia, Actinocorallia, and Jiangella species from endophytic environments. At least 19 isolates are considered novel taxa by our current research. In addition, all 46 isolates were tested for antimicrobial activity and were screened for the presence of genes encoding polyketide synthetases and nonribosomal peptide synthetases. The results confirm that the medicinal plants of Xishuangbanna represent an extremely rich reservoir for the isolation of a significant diversity of actinobacteria, including novel species, that are potential sources for the discovery of biologically active compounds.

Pseudonocardia endophytica sp. nov., isolated from the pharmaceutical plant Lobelia clavata.

An endophytic actinomycete strain, designated YIM 56035(T), was isolated from the inner tissue of the traditional Chinese medicinal plant Lobelia clavata. The strain stained Gram-positive, was aerobic and exhibited branching, white aerial mycelium and yellowish-brown substrate mycelium. The strain formed spore chains on aerial hyphae. The G+C content of the genomic DNA was 70.3 mol%. On the basis of morphological, physiological, chemotaxonomic and phylogenetic characteristics, strain YIM 56035(T) was assigned to the genus Pseudonocardia. Analysis of 16S rRNA gene sequences showed 98.5, 97.3, 97.3 and 97.1 % similarity to the closely related type strains Pseudonocardia kongjuensis LM 157(T), Pseudonocardia autotrophica IMSNU 20050(T), Pseudonocardia ammonioxydans H9(T) and Pseudonocardia compacta IMSNU 20111(T), respectively. The results of DNA-DNA hybridizations and comparison of some phenotypic characteristics revealed that the strain represents a novel species of the genus Pseudonocardia. The name Pseudonocardia endophytica sp. nov. is proposed, with the type strain YIM 56035(T) (=DSM 44969(T) =CCTCC AA 206026(T) =KCTC 19150(T)).

Glycomyces endophyticus sp. nov., an endophytic actinomycete isolated from the root of Carex baccans Nees.

An actinomycete, designated strain YIM 56134(T), was isolated from the root of a Chinese medicinal plant, Carex baccans Nees, collected from Yunnan, south-west China, and subjected to a polyphasic taxonomic study. An analysis of 16S rRNA gene sequence similarities showed that strain YIM 56134(T) was a member of the genus Glycomyces, being most closely related to Glycomyces algeriensis NRRL B-16327(T) (99.0 % similarity), Glycomyces lechevalierae DSM 44724(T) (99.0 %), Glycomyces rutgersensis IFO 14488(T) (98.9 %) and Glycomyces harbinensis IFO 14487(T) (98.7 %). Strain YIM 56134(T) could be distinguished from other established Glycomyces species on the basis of relatively low sequence similarity (<97 %). Phenotypic and chemotaxonomic data supported the affiliation of this strain to the genus Glycomyces. The results of DNA-DNA hybridization and some physiological and biochemical tests allowed differentiation of the strain from related Glycomyces species. Therefore, strain YIM 56134(T) represents a novel species of the genus Glycomyces, for which the name Glycomyces endophyticus sp. nov. is proposed. The type strain is YIM 56134(T) (=KCTC 19152(T) =DSM 45002(T)).

Streptomonospora alba sp. nov., a novel halophilic actinomycete, and emended description of the genus Streptomonospora Cui et al. 2001.

A halophilic actinomycete, strain YIM 90003(T), was isolated from a soil sample collected from Xinjiang Province, China, by using starch-casein agar with a salt concentration of 20 % (w/v), pH 7.0. The strain grew well on most media tested. No diffusible pigment was produced. Aerial mycelium and substrate mycelium were well developed on most media. The aerial mycelium formed short spore chains, bearing non-motile, straight to flexuous spores with wrinkled surfaces. The cell walls of strain YIM 90003(T) contained meso-diaminopimelic acid as the diagnostic diamino acid. Cell-wall hydrolysates contained galactose and arabinose. Menaquinone composition varied with the medium used for cell cultivation; on glucose-yeast extract medium supplemented with 10 % NaCl, the major menaquinone was MK-9(H(4)), while, on vitamin-enriched ISP 2 medium, the major menaquinones were MK-10(H(2)), MK-9(H(8)) and MK-10(H(4)). Phospholipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, diphosphatidyl glycerol, methylphosphatidylethanolamine, phosphatidylserine, phosphatidylcholine and an unidentified phospholipid. 16S rRNA gene sequence analysis showed Streptomonospora salina as the closest phylogenetic neighbour. On the basis of these analyses, strain YIM 90003(T) is a member of the genus Streptomonospora, though its properties do not match the generic description fully with respect to the menaquinone composition and peptidoglycan amino acid. Analyses of mechanically disrupted cell walls of the type species, Streptomonospora salina DSM 44593(T), and strain YIM 90003(T), purified by tryptic digestion and subsequent SDS treatment, revealed the exclusive presence of meso-diaminopimelic acid as the diagnostic diamino acid of peptidoglycan. Thus, the genus description of Streptomonospora, indicating the presence of several amino acids usually not found in the peptidoglycan moiety, is therefore emended. DNA-DNA hybridization and comparison of physiological and chemotaxonomic characteristics demonstrated strain YIM 90003(T) to be different from Streptomonospora salina. The name Streptomonospora alba sp. nov. is proposed, with strain YIM 90003(T) (=CCTCC AA001013(T)=DSM 44588(T)) as the type strain.