Aims:  The aim of this study was to screen antitumour and antimicrobial activities of endophytic actinomycetes isolated from pharmaceutical plants in rainforest in Yunnan province, China. Methods and Results:  Antitumour activity was studied by the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay and antimicrobial activity was determined by agar well diffusion method. The high bioactive endophytic isolates were identified and further investigated for the presence of polyketide synthases (PKS‐I, PKS‐II) and nonribosomal peptide synthetases (NRPS) sequences by specific amplification. The molecular identification confirmed that the 41 isolates showed significant activities were members of the genus Streptomyces. Among them, 31·7% of endophytic streptomycete cultures were cytotoxic against A549 cells, 29·3% against HL‐60 cells, 85·4% against BEL‐7404 cells, 90·2% against P388D1 cells, 65·9% were active against Escherichia coli, 24·4% against Staphylococcus aureus, 31·7% against Staphylococcus epidermidis, 12·2% against Candida albicans and no strain displayed antagonistic activity against Klebsiella pneumoniae. High frequencies of positive PCR amplification were obtained for PKS‐I (34·1%), PKS‐II (63·4%) and NRPS (61·0%) biosynthetic systems. Conclusions:  Many endophytic streptomycetes isolated from pharmaceutical plants in rainforest possess remarkable and diverse antitumour and antimicrobial bioactivities. Significance and Impact of the Study:  These endophytic streptomycetes are precious resources obtained from rainforests, and they could be a promising source for bioactive agents.

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Four novel Gram-stain-negative, rod-shaped, and non-motile bacterial strains, SLG210-21(T), SLG210-4, SLG210-5 and SLG210-14, were isolated from oil-contaminated saline soil in Shengli Oilfield, China. Growth were observed at 25-42 °C (optimum 37 °C), in the presence of 0-10 % (w/v) NaCl (optimum 0-1 %) and at pH 4.0-10.0 (optimum pH 7.6-8.6). All the strains were positive for catalase and α, β-galactosidase activities and nitrogen reduction, and negative for oxidase activity, glucose fermentation and hydrolysis of agar, starch, gelatin, Tween 40, 60 and 80. The DNA G+C contents of the four strains were 41.3-43.0 mol% and the predominant respiratory quinones were all menaquinone-7. The major fatty acids were iso-C15:0, anteiso-C15:0, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16:1 ω5c and summed feature 9 (iso-C17:1 ω9c and/or 10-methyl C16:0), while the polar lipids consisted of phosphatidylcholine, phosphatidylethanolamine, glycolipid, two unidentified phospholipids and two unidentified amino lipids. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the four strains clustered together to form a stable branch in the family Cyclobacteriaceae, and were most closely related to the genera Cyclobacterium and Echinicola with the 16S rRNA gene sequence similarities being 88.6-90.3 and 89.6-91.4 %, respectively. DNA-DNA hybridization between SLG210-21(T) and the other three strains showed the relatedness of 93.8 ± 4.5, 96.2 ± 4.2 and 82.3 ± 4.8 %, respectively. Based on the polyphasic analysis, a novel species in a new genus, Negadavirga Shengliensis gen. nov., sp. nov., is proposed with SLG210-21(T) (=LMG 27737(T) = CGMCC1.12768(T)) [corrected] as the type strain.

Strain YIM B00363 T , a Gram-positive, aerobic, non-motile, rod-shaped, spore-forming bacterium, was isolated from saline soil samples collected from a salt lake in Xinjiang province, northwest China, and was characterized using a polyphasic approach. The optimum growth temperature was 37 °C and the optimum pH was 7.5-8.0. The major menaquinone was MK-7; anteiso-C 15:0 (53.52%), iso-C 15:0 (15.04%) and C 16:0 (12.76%) were the predominant cellular fatty acids. The diagnostic diamino acid of the cell wall peptidoglycan was meso-diaminopimelic acid. The phospholipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, unidentified phospholipids, unidentified glycolipids and unknown lipids. The DNA G + C content of the type strain was 50.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain YIM B00363 T belonged to a cluster comprising species of the genus Paenibacillus. The nearest relatives were P. residui MC-246 T and P. senegalensis JC66 T , with 93.2% and 92.8% gene sequence similarities, respectively. On the basis of its phenotypic characteristics and phylogenetic distinctivenes, strain YIM B00363 T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus turpanensis sp. nov. is proposed. The type strain is YIM B00363 T (= CGMCC 1.17507 T = KCTC 43184 T).