Two new alkaloids, strepchazolins A (1) and B (2), together with a previously reported compound, streptazolin (3), were isolated from a marine actinomycete, Streptomyces chartreusis NA02069, collected in the Coast of Hainan Island, China. The structures of new compounds were determined by extensive NMR, mass spectroscopic and X-ray crystallographic analysis, as well as modified Mosher’s method. Compound 1 showed weak anti-Bacillus subtilis activity with the MIC value of 64.0 μM, and weak inhibitory activity against acetylcholinesterase (AChE) in vitro with IC₅₀ value of 50.6 μM, while its diastereoisomer, Compound 2, is almost inactive.

Members of the genus Bacillus and related spore-forming genera are ubiquitous. However, Bacillus-like species isolated from marine sediments have attracted less interest than their terrestrial relatives. Here, we investigated the diversity of Bacillus-like bacterial communities in the sediments of the Bamenwan mangrove wetland in Hainan, China, using culture-dependent and culture-independent methods, and present the first report on this subject. We also discovered some potential novel species from the sediment samples. Four families, Bacillaceae (58%), Paenibacillaceae (22%), Alicyclobacillaceae (15%), and Planococcaceae (5%), and 9 genera, Bacillus (42%), Paenibacillus (16%), Halobacillus (13%), Alicyclobacillus (11%), Rummeliibacillus (5%), Cohnella (5%), Tumebacillus (4%), Pontibacillus (3%), and Aneurinibacillus (2%), were identified by pyrosequencing. In contrast, only 4 genera, Bacillus (57%), Paenibacillus (23%), Halobacillus (14%), and Virgibacillus (6%), were detected by the culture-dependent method. In the 16S rDNA sequencing analysis, the isolates HB12036 and HB12037 were closest to Bacillus okuhidensis Kh10-101^T and Paenibacillus xylanilyticus XIL14^T with similarities of 94.8% and 95.9%, respectively, indicating that these were novel species. Bacillus sp. HB12035 and HB12040 exhibited antimicrobial activity against Staphylococcus aureus ATCC 25923, and Bacillus sp. HB12033 exhibited antimicrobial activity against Ustilago scitaminea Syd.

A novel strain of the classActinobacteriawas isolated from a seawater sample collected in the South China Sea using modified R2A agar plates. The strain was a Gram-stain-positive, non-motile, non-spore-forming, catalase-positive, irregular rod-shaped bacterium. The strain grew at 4–45 °C and pH 5.0–10.2, and tolerated 5 % (w/v) NaCl. Based on its 16S rRNA gene sequence, the organism was related phylogenetically to members of the generaFodinibacter(96.7 % similarity),Lapillicoccus(96.5 %),Knoellia(95.0–95.8 %),Oryzihumus(95.6 %) andHumibacillus(95.6 %). The cell-wall containedl-ornithine as the major diagnostic diamino acid in the peptidoglycan. MK-8(H₄) was the predominant menaquinone. Major cellular fatty acids were iso-C_18 : 1ω9c, iso-C_16 : 0, iso-C_15 : 0and C_17 : 0. The G+C content of the DNA was 69.6 mol%. Phenotypic and phylogenetic data revealed that this strain represents a novel species in a new genus of the familyIntrasporangiaceae, for which the nameOrnithinibacter aureusgen. nov., sp. nov. is proposed; the type strain ofOrnithinibacter aureusis HB09001^T(=CGMCC 1.10341^T=DSM 23364^T).

Two Gram-stain-positive, facultatively aerobic, endospore-forming and rod-shaped bacteria, designated DB13031T and DB13311, were isolated from the soil of the Jiaxi Nature Reserve in Hainan, PR China. 16S rRNA gene analysis of strains DB13031T and DB13311 showed that they fell within the Paenibacillus cluster, with highest similarities to Paenibacillus cucumis AP-115T (98.4 and 98.3 %, respectively), Paenibacillus barcinonensis BP-23T (98.3 and 98.2 %, respectively) and Paenibacillus oceanisediminis L10T (97.7 and 97.7 %, respectively). The DNA–DNA hybridization values between strain DB13031T and the type strains of its closest related species were 48.2, 38.1 and 43.5 %. Strain DB13031T contained menaquinone-7 (MK-7) as the predominant isoprenoid quinone and anteiso-C15 : 0, iso-C16 : 0 and C16 : 0 as the major cellular fatty acids. The cell-wall peptidoglycan was of the A1γ type and the major polar lipid profiles were diphosphatidylglycerol, phosphatidylethanolamine, four unknown aminophospholipids and four unknown phospholipids. Based on the phenotypic and genotypic data, it is proposed that the two isolates represent a novel species of the genus Paenibacillus , for which the name Paenibacillus silvae sp. nov. is proposed. The type strain is DB13031T (=CGMCC 1.12770T=DSM 28013T).