Qing-Yi Xie

Actinomycetes for marine drug discovery isolated from mangrove soils and plants in China.

The mangrove ecosystem is a largely unexplored source for actinomycetes with the potential to produce biologically active secondary metabolites. Consequently, we set out to isolate, characterize and screen actinomycetes from soil and plant material collected from eight mangrove sites in China. Over 2,000 actinomycetes were isolated and of these approximately 20%, 5%, and 10% inhibited the growth of Human Colon Tumor 116 cells, Candida albicans and Staphylococcus aureus, respectively, while 3% inhibited protein tyrosine phosphatase 1B (PTP1B), a protein related to diabetes. In addition, nine isolates inhibited aurora kinase A, an anti-cancer related protein, and three inhibited caspase 3, a protein related to neurodegenerative diseases. Representative bioactive isolates were characterized using genotypic and phenotypic procedures and classified to thirteen genera, notably to the genera Micromonospora and Streptomyces. Actinomycetes showing cytotoxic activity were assigned to seven genera whereas only Micromonospora and Streptomyces strains showed anti-PTP1B activity. We conclude that actinomycetes isolated from mangrove habitats are a potentially rich source for the discovery of anti-infection and anti-tumor compounds, and of agents for treating neurodegenerative diseases and diabetes.

Micromonospora rhizosphaerae sp. nov., isolated from mangrove rhizosphere soil.

Strain 211018(T) was isolated from mangrove Excocaria agallocha rhizosphere soil. 16S rRNA gene sequence analysis showed the highest similarity to the type strains of Micromonospora olivasterospora DSM 43868(T) (98.6 %) and Micromonospora pattaloongensis TJ2-2(T) (98.4 %). gyrB gene sequence analysis also indicated that strain 211018(T) should be assigned to the genus Micromonospora. The characteristic whole-cell sugars are xylose, mannose and arabinose. The predominant menaquinone is MK-9(H(4)) and the major fatty acids are iso-C(15 : 0) (27.5 %), 10-methyl C(17 : 0) (14.2 %), C(17 : 1)ω8c (12.8 %), iso-C(16 : 0) (12.6 %), anteiso-C(15 : 0) (6.1 %), iso-C(17 : 0) (4.1 %) and anteiso-C(17 : 0) (4.0 %). The phospholipid profile comprises phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. The DNA G+C content is 70.8 mol%. The chemotaxonomic data of the strain coincided with those of the genus Micromonospora. Furthermore, a combination of DNA-DNA hybridization results and some physiological and biochemical properties indicated that the novel strain could be readily distinguished from the closest phylogenetic relatives. On the basis of these phenotypic and genotypic data, strain 211018(T) represents a novel species of the genus Micromonospora, for which the name Micromonospora rhizosphaerae sp. nov. is proposed. The type strain is 211018(T) (=CGMCC 4.5599(T) =DSM 45431(T)).

Streptomyces qinglanensis sp. nov., isolated from mangrove sediment

A Streptomyces-like strain, 172205(T), was obtained from mangrove soil collected at Qinglan Harbour, Wenchang, Hainan, China. The strain was characterized by white aerial mycelium and long spore chains. Comparison of 16S rRNA gene sequences indicated that the strain represents a novel member of the genus Streptomyces, exhibiting highest levels of similarity (<98.29%) to the type strains of members of the genus Streptomyces. However, DNA-DNA relatedness and phenotypic data readily distinguished strain 172205(T) from phylogenetically related type strains. The predominant menaquinones were MK-9(H(6)) and MK-9(H(8)). The major fatty acids were iso-C(15:0) (10.31%), anteiso-C(15:0) (35.19%), iso-C(16:0) (20.24%) and anteiso-C(17:0) (10.05%). The diagnostic phospholipid was phosphatidylethanolamine. The cell wall contained ll-diaminopimelic acid and meso-diaminopimelic acid and whole-cell hydrolysates contained ribose, galactose and glucose. The results of DNA-DNA hybridization, physiological and biochemical tests allowed the genotypic and phenotypic differentiation of strain 172205(T) from phylogenetically related type strains. Therefore, strain 172205(T) is considered to represent a novel species of the genus Streptomyces, for which the name Streptomyces qinglanensis sp. nov. is proposed. The type strain is 172205(T) (=CGMCC 4.6825(T) =DSM 42035(T)).

Jishengella endophytica gen. nov., sp. nov., a new member of the family Micromonosporaceae

A novel endophytic actinomycete, designated strain 202201(T), was isolated from an Acanthus illicifolius root collected from the mangrove reserve zone in Hainan Province, China. Phylogenetic analysis based on 16S rRNA gene sequences suggested that strain 202201(T) fell within the family Micromonosporaceae. The strain formed an extensively branched substrate mycelium, which carried uneven warty-surfaced spores. Cell walls of strain 202201(T) contained meso-diaminopimelic acid and xylose, mannose, arabinose, ribose and glucose were detected as whole-cell sugars. The acyl type of the cell-wall polysaccharides was glycolyl. The major menaquinones were MK-9(H(4)), MK-9(H(6)), MK-9(H(8)) and MK-10(H(4)). The polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol mannoside and phosphatidylserine. The major cellular fatty acids were 10-methyl-C(17 : 0), iso-C(15 : 0), iso-C(16 : 0) and C(17 : 1)ω8c. The DNA G+C content was 72.3 mol%. On the basis of the morphological and chemotaxonomic characteristics, phylogenetic analysis and characteristic patterns of 16S rRNA gene signature nucleotides, strain 202201(T) ( = CGMCC 4.5597(T ) = DSM 45430(T)) represents a novel species of a new genus within the family Micromonosporaceae, for which the name Jishengella endophytica gen. nov., sp. nov. is proposed.

Micromonospora sonneratiae sp. nov., isolated from a root of Sonneratia apetala.

A novel endophytic actinomycete, strain 274745(T), was isolated from a root of Sonneratia apetala collected in a mangrove forest in Sanya, Hainan province, China. The 16S rRNA gene sequence of strain 274745(T) showed the greatest similarity to Micromonospora pattaloongensis TJ2-2(T) (98.3 %). Phylogenetic analysis based on the gyrB gene also supported the close relationship of these two strains. The predominant menaquinone was MK-10(H8) and the major fatty acids were iso-C15 : 0, C17 : 0 and anteiso-C15 : 0. The characteristic whole-cell sugars were xylose and mannose. The cell wall contained meso-diaminopimelic acid and glycine. The polar lipid profile mainly comprised phosphatidylethanolamine, phosphatidylinositol and diphosphatidylglycerol. The DNA G+C content was 71.6 mol%. Furthermore, a combination of DNA-DNA relatedness and some physiological and biochemical properties indicated that the novel strain could be readily distinguished from the closest phylogenetic relatives. On the basis of these phenotypic and genotypic data, strain 274745(T) represents a novel species of the genus Micromonospora, for which the name Micromonospora sonneratiae sp. nov. is proposed. The type strain is 274745(T) ( = CCTCC AA 2012003(T) = DSM 45704(T)).

Nonomuraea wenchangensis sp. nov., isolated from mangrove rhizosphere soil

Strain 210417(T), which forms highly branched substrate and aerial mycelia, is a Gram-positive, aerobic and non-motile actinomycete isolated from mangrove rhizosphere soil. 16S rRNA gene sequence analysis showed that the strain should be classified in the genus Nonomuraea, being most closely related to the type strains of Nonomuraea coxensis (99.6 %) and Nonomuraea bangladeshensis (99.3 %). Chemotaxonomic properties [madurose as the major sugar in the cell wall; meso-diaminopimelic acid and N-acetylmuramic acid in the peptidoglycan; MK-9(H(4)) as the major menaquinone; iso-C(16 : 0) (24.1 %) as major fatty acid; and phospholipid pattern type IV] are consistent with the assignment of strain 210417(T) to the genus Nonomuraea. Strain 210417(T) could be differentiated from the closely related species N. coxensis and N. bangladeshensis by morphological, physiological, biochemical and chemotaxonomic properties, 16S rRNA gene sequence analysis and DNA-DNA hybridization results. It is therefore proposed that strain 210417(T) represents a novel species of the genus Nonomuraea, for which the name Nonomuraea wenchangensis sp. nov. is given; the type strain is 210417(T) ( = CGMCC 4.5598(T)  = DSM 45477(T)).

Streptomyces sanyensis sp. nov., isolated from mangrove sediment.

A novel strain, 219820(T), whose metabolites were found to be active against tumour cells, was isolated and characterized. The isolate belonged to the genus Streptomyces and had white to grey aerial mycelium and long chains of smooth spores in the aerial mycelium. A phylogenetic tree based on 16S rRNA gene sequences showed that strain 219820(T) had highest similarity to members of the genus Streptomyces and was most closely, albeit loosely, associated with Streptomyces crystallinus NBRC 15401(T) (98.624 % similarity), Streptomyces melanogenes NBRC 12890(T) (98.565 %) and Streptomyces noboritoensis NBRC 13065(T) (98.564 %). However, DNA-DNA relatedness and phenotypic data readily distinguished strain 219820(T) from these phylogenetically related type strains. It is evident from the combination of genotypic and phenotypic data that strain 219820(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces sanyensis sp. nov. is proposed; the type strain is 219820(T) ( = CGMCC 4.5626(T)  = DSM 42014(T)).

Streptomyces shenzhenensis sp. nov., a novel actinomycete isolated from mangrove sediment

An actinomycete strain, which was designated 172115T, was isolated from mangrove soil in Shenzhen, China. Strain 172115T fell within the genus Streptomyces in the 16S rRNA gene tree and could be grouped into this genus based on its chemotaxonomic and morphological data. The strain shared the highest 16S rRNA gene sequence similarities with Streptomyces lanatus NBRC 12787T (AB184845) (98.29%) and Streptomyces lucensis NBRC 13056T (AB184280) (98.26%). The DNA–DNA hybridization values between strain 172115T and the two most closely related type strains were low enough to justify the assignment of the strain to a novel species. On the basis of these phenotypic, phylogenetic and chemotaxonomic characteristics, 172115T represents a novel species of the genus Streptomyces, for which, the name Streptomyces shenzhenensis sp. nov. is proposed for strain 172115T (=CCTCC AA 2011001T=DSM 42034T).

Microbispora hainanensis sp. nov., isolated from rhizosphere soil of Excoecaria agallocha in a mangrove

Strain 211020(T) was isolated from rhizosphere soil of Excoecaria agallocha in a mangrove in Hainan, China. The strain produced longitudinal pair spores branching from aerial hyphae. 16S rRNA gene sequence analysis showed that the isolate belonged to the genus Microbispora, exhibiting the highest 16S rRNA gene sequence similarity (98.75 %) to Microbispora corallina JCM 10267(T) with a low DNA-DNA relatedness value (13 ± 0.6 %). The isolate contained meso-diaminopimelic acid as the diagnostic diamino acid but madurose was not detected. The predominant menaquinones were MK-9(H(4)), MK-9(H(2)) and MK-9(H(0)), and the major fatty acids were iso-C(16 : 0), iso-C(15 : 0) and C(17 : 0). The phospholipid profile of strain 211020(T) comprised phosphatidylinositol mannoside, phosphatidylethanolamine, diphosphatidylglycerol and phospholipids of unknown structure containing glucosamine. The DNA G+C content was 70.8 mol%. On the basis of phenotypic and genotypic data, strain 211020(T) can be distinguished as a novel species of the genus Microbispora, for which the name Microbispora hainanensis sp. nov., is proposed. The type strain is 211020(T) ( = CGMCC 4.5595(T) = DSM 45428(T)).

Brachybacterium huguangmaarense sp. nov., isolated from Lake sediment.

A Gram-stain positive strain, M1T, was isolated from the sediment of Maar Lake in Zhanjiang, Guangdong Province, China. The diagnostic cell-wall diamino acid was meso-diaminopimelic acid, and mycolic acids were not detected. The polar lipid profile of strain M1T consisted of diphosphatidylglycerol, phosphatidylglycerol, an unidentified phospholipid and an unknown glycolipid. The predominant quinone was MK-7, with MK-6 as a minor component. The major fatty acids were anteiso-C15:0 and anteiso-C17:0, with iso-C18:0 as a minor component. The DNA G+C content of the genomic DNA was 71.0 mol%. 16S rRNA gene sequence analysis showed that strain M1T belongs to the family Dermabacteraceae, sharing highest sequence similarity with Brachybacterium nesterenkovii JCM 11648T (98.1%). Furthermore, a combination of DNA-DNA relatedness and physiological and biochemical properties indicated that the novel strain could be readily distinguished from its closest phylogenetic relatives. On the basis of these phenotypic and genotypic data, strain M1T represents a novel species of the genus Brachybacterium, for which the name Brachybacterium huguangmaarense sp. nov. is proposed. The type strain is M1T (=CCTCC AB 2012866T=DSM 26370T).