Chitinolyticbacter albus sp. Nov., A Novel Chitin-Degrading Bacterium Isolated from Ancient Wood Rhizosphere Soil.

In this study, a novel aerobic mesophilic bacterial strain with capable of degrading chitin, designated YIM B06366T, was isolated and classified. The rod-shaped, Gram-stain-negative, on-spore-forming bacterium originated from rhizosphere soil sample collected in Kunming City, Yunnan Province, southwest PR China. Strain YIM B06366T exhibited growth at temperatures between 20 and 35 °C (optimum, 30 °C) and at pH 6.0-8.0 (optimum, pH 6.0). The analysis of 16S rRNA gene sequence similarity revealed that strain YIM B06366T was most closely related to type strain Chitinolyticbacter meiyuanensis SYBC-H1T (98.9%). Phylogenetic analysis based on genome data indicated that strain YIM B06366T should be assigned to the genus Chitinolyticbacter. The Average Nucleotide Identity (ANI) and digital DNA-DNA Hybridization (dDDH) values between strain YIM B06366T and the reference strain Chitinolyticbacter meiyuanensis SYBC-H1T were 84.4% and 27.7%, respectively. The major fatty acids included Summed Feature 3 (C16:1 ω6c/C16:1 ω7c), Summed Feature 8 (C18:1 ω6c/C18:1 ω7c), and C16:0. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, aminophospholipids, and two unidentified phospholipids. The predominant menaquinone was Q-8, and the genomic DNA G + C content was 64.1%. Considering the polyphasic taxonomic evidence, strain YIM B06366T is proposed as a novel species within the genus Chitinolyticbacter, named Chitinolyticbacter albus sp. nov. (type strain YIM B06366T = KCTC 92434T = CCTCC AB 2022163T).

Propioniciclava soli sp. nov., isolated from forest soil, Yunnan, China, and reclassification of the genus Brevilactibacter into the genus Propioniciclava, and Brevilactibacter sinopodophylli, Brevilactibacter flavus, and Brevilactibacter coleopterorum as Propioniciclava sinopodophylli comb. nov., Propioniciclava flava comb. nov., and Propioniciclava coleopterorum comb. nov., respectively.

A Gram-stain-positive, coccus-shaped, facultatively anaerobic, non-motile bacterial strain, designated YIM S02567T, was isolated from a forest soil sample collected from Gejiu City, Yunnan Province, southwest PR China. Growth was observed at 10-45 °C, at pH 6.0-9.5, in the presence of up to 4.0% (w/v) NaCl on R2A medium. The results of 16S rRNA gene sequence similarity analysis showed that strain YIM S02567T was most closely related to the type strain of Brevilactibacter sinopodophylli (95.4%) and Propioniciclava tarda (94.7%), and phylogenetic analysis based on genome data showed that strain YIM S02567T should be assigned to the genus Propioniciclava. The cell-wall diamino acid was meso-diaminopimelic acid. The major cellular fatty acids were identified as anteiso-C15:0 and C16:0, and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and two unidentified glycolipids. The predominant menaquinone was MK-9(H4). The genomic DNA G + C content was 71.2 mol%. Based on the polyphasic taxonomic evidence, strain YIM S02567T is assigned to a novel member of the genus Propioniciclava, for which the name Propioniciclava soli sp. nov., (type strain YIM S02567T = CCTCC AB 2020128T = CGMCC 1.18504T = KCTC 49478T) is proposed. Furthermore, we propose the reclassification of Brevilactibacter as Propioniciclava gen. nov.

Viridibacillus soli sp. nov., isolated from forest soil in Ailaoshan National Nature Reserve.

A Gram stain-positive, rod-shaped, and subterminal endospore-forming bacterium, designated strain YIM B01967T, was isolated from a forest soil sample collected in Ailaoshan National Nature Reserve, Yuxi City, Xinpin county, Yunnan province, China. Strain YIM B01967T showed the highest 16S rRNA gene sequence similarity with Viridibacillus arvi (99.1%) and Viridibacillus arenosi (98.9%). Based on the phylogenetic and 16S rRNA gene sequence results, strain YIM B01967T was affiliated to the genus Viridibacillus. The growth of YIM B01967T was observed at 15-35 °C (optimum, 28 °C), pH 7.0-9.0 (optimum, pH 7.5) and in the presence of 0-2% (w/v) NaCl (optimum in 2% NaCl). The cell wall sugars include ribose, glucose, arabinose, galactose, and mannose. The quinone system consisted of the major compound MK-8 and moderate amounts of MK-7. The major fatty acids (> 10%) included iso-C15:0, anteiso-C15:0, C16:1 ω10c. The major polar lipids profile included DPG, PME. The cell wall peptidoglycan was most likely of the type A4α with an L-Lys-D-Asp interpeptide bridge. The genomic DNA G + C content of strain YIM B01967T was 36.3 mol%. The ANI and digital DNA-DNA hybridization (dDDH) values between strain YIM B01967T and Viridibacillus arvi DSM 16317 T, Viridibacillus arenosi DSM 16319 T were 61.0% and 32.1%, 60.0% and 33.1% based on the draft genome sequence. The results support the conclusion that strain YIM B01967T represents a novel species of the genus Viridibacillus, for which the name Viridibacillus soli sp. nov., is proposed. The type strain is YIM B01967T (= KCTC 43249 T = CGMCC 1.18436 T).

[Recent advances in biosynthesis of forskolin].

Forskolin is a complex labdane plant diterpenoid, which has been used in the treatment of a variety of diseases based on its activity as an activator of adenosine monophosphate(cAMP) cyclase. Natural forskolin exists only in the cork layer of the root of Coleus forskohlii. Due to the complexity of the extraction and chemical synthesis processes, the yield and purity of forskolin cannot meet commercial requirements. In recent years, with the rapid development of synthetic biology and the analysis and interpretation of many diterpene biosynthetic pathways, a new approach has been provided for the green production of forskolin. In this paper, the structure, activity, biosynthetic pathway and the heterologous biosynthesis of forskolin were reviewed. The problems and solutions in the heterologous biosynthesis of forskolin were also discussed and summarized, which will provide references for the construction of high-yielding forskolin engineering strains.

Cloning and Characterization of a Ginsenoside-Hydrolyzing α-L-Arabinofuranosidase, CaAraf51, From Cellulosimicrobium aquatile Lyp51.

Moutai Jiuqu is a famous aromatic raw material of Maotai flavor liquor in China. It is brewed at high temperature and contains many kinds of bacteria, molds, and yeasts. There are many useful glycoside hydrolases in these microfloras, from which efficient glycoside hydrolases can be screened for biotransformation of natural saponins. In this study, an α-L-arabinofuranosidase gene (CaAraf51, 1524 bp, 507 amino acid, 55.07 kDa, and pI = 4.8) was cloned from Cellulosimicrobium aquatile Lyp51, which was isolated from the Maotai Jiuqu. The CaAraf51 was heterogeneously expressed in E. coli BL21 (DE3) and purified by N-terminal His-tag with the Ni2+-affinity column chromatography. The results show that purified CaAraf51 has a 6.8-fold purification factor and specific activity of 15 U/mg. Under optimal conditions (pH 5.0, temperature 40 °C), kinetic parameters Km of CaAraf51 for pNPαAraf and Rc were 1.1 and 0.57 mM, the Vmax were 25 and 6.25 µmol/min/mg, respectively. 90% of 0.87 mg Rc substrate can be transformed by 9.6 U purified CaAraf51 in 1 mL reaction system under suitable conditions (30 °C, pH 7.5 phosphate buffer, 1 h). In addition, we also tested the effects of metal ions and chemical agents on the activity of CaAraf51. According to systematically studied its function and enzymatic properties, CaAraf51 has excellent value and potential of biotransformation Rc into Rd.

A new phenylspirodrimane dimer from the fungus Stachybotrys chartarum.

A new phenylspirodrimane dimer, named stachartarin A (1), was isolated from cultures of the tin mine tailings-associated fungus Stachybotrys chartarum. Its structures were elucidated by means of spectroscopic methods. At the same time, the compound was tested for its cytotoxicity against HL-60, SMMC-7721, A-549, MCF-7, and SW480 cells.

A novel phenylspirodrimane dimer from cultures of the fungus Stachybotrys chartarum.

Stachartone A (1), a novel phenylspirodrimane dimer, was isolated from cultures of the tin mine tailings-associated fungus Stachybotrys chartarum. Its structure was elucidated by means of spectroscopic methods. At the same time, compound (1) was tested for its cytotoxicity against five human cancer cell lines.

Two new diketopiperazines from the tin mine tailings-derived fungus Schizophyllum commune YIM DT 10058.

Two new diketopiperazines, named diphenylalazine C (1) and epicoccin U (2), together with six known compounds (3-8) were isolated from the EtOAc extract of the fermentation broth of the tin mine tailings-derived fungus Schizophyllum commune YIM DT 10058. Their structures were elucidated by detailed analysis of spectroscopic data and comparison with related known compounds. Compounds 1 and 2 exhibited weak antibacterial and cytotoxic activities.

Griseusins F and G, spiro-naphthoquinones from a tin mine tailings-derived alkalophilic Nocardiopsis species.

Griseusins F (1) and G (2), two 2a-hydro-8a-(2-oxopropyl)-substituted spiro-naphthoquinones with a previously undescribed C23 polyketide skeleton, were isolated from a Yunnan tin mine tailings-derived alkalophilic actinomycete, Nocardiopsis sp. YIM DT266. Their complete structure assignments with the absolute stereochemistry were elucidated by spectroscopic data, X-ray crystal diffraction, calculation of optical rotation, and CD spectroscopic analysis. Compounds 1 and 2 exhibited strong cytotoxicity (IC50 0.37-0.82 µM) and antibacterial activity (MIC 0.80-1.65 µg/mL) against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) in vitro.

Significantly enhanced production of acarbose in fed-batch fermentation with the addition of S-adenosylmethionine.

Acarbose, a pseudo-oligosaccharide, is widely used clinically in therapies for non-insulin-dependent diabetes. In the present study, S-adenosylmethionine (SAM) was added to selected media in order to investigate its effect on acarbose fermentation by Actinoplanes utahensis ZJB- 08196. Acarbose titer was seen to increase markedly when concentrations of SAM were added over a period of time. The effects of glucose and maltose on the production of acarbose were investigated in both batch and fed-batch fermentation. Optimal acarbose production was observed at relatively low glucose levels and high maltose levels. Based on these results, a further fed-batch experiment was designed so as to enhance the production of acarbose. Fed-batch fermentation was carried out at an initial glucose level of 10 g/l and an initial maltose level of 60 g/l. Then, 12 h post inoculation, 100 micromol/l SAM was added. In addition, 8 g/l of glucose was added every 24 h, and 20 g/l of maltose was added at 96 h. By way of this novel feeding strategy, the maximum titer of acarbose achieved was 6,113 mg/l at 192 h. To our knowledge, the production level of acarbose achieved in this study is the highest ever reported.

Plasticity in gilvocarcin-type C-glycoside pathways: discovery and antitumoral evaluation of polycarcin V from Streptomyces polyformus.

Gilvocarcin-type polyketide glycosides represent some of the most powerful antitumor therapeutics. Bioactivity-guided fractionation of a culture extract of Streptomyces polyformus sp. nov. (YIM 33176) yielded the known gilvocarcin V (2) and a novel related compound, polycarcin V (1). Structure elucidation by NMR and chemical derivatization revealed that the congener (1) features a C-glycosidically linked alpha-L-rhamnopyranosyl moiety in lieu of the D-fucofuranose. The concomitant production of two distinct furanosyl and pyranosyl C-glycosides that share the same aglycone is unprecedented in bacteria. A conversion of both isoforms via a quinone methide intermediate can be ruled out, thus pointing to two individual C-glycosylation pathways. Cytotoxicity profiling of polycarcin V in a panel of 37 tumor cell lines indicated significant antitumoral activity with a pronounced selectivity for non-small-cell lung cancer, breast cancer and melanoma cells. As the antiproliferative fingerprint is identical to that of actinomycin D, the known DNA interaction of gilvocarcins was established as a general principle of antitumorigenic activity.

Griseusin D, a new pyranonaphthoquinone derivative from a alkaphilic Nocardiopsis sp.

A new pyranonaphthoquinone antibiotic, griseusin D (1) was isolated from the cultural fluid of the alkaphilic Nocardiopsis sp. The structure was determined as 5'-one-4-hydroxy-12-methoxygriseusin by spectroscopic methods, comparison with reported data and single-crystal X-ray analysis. 1 displayed strong cytotoxicity against human leukemia cells (HL60) and modest cytotoxicity against human lung adenocarcinoma cell lines (AGZY) with IC(50) values of 0.23 and 19.6 microg/ml, respectively. It also exhibited weak antifungal activity against Alternaria alternate with MIC of 140 microg/ml.

Streptomyces nanningensis sp. nov. a novel Streptomycete from forest soil.

A strain YIM 33098T (= CCTCC AA001027T = DSM 41831T) was isolated from a forest soil sample collected from Nanning in Guangxi Province, China, in the course of screening for producers of new drug lead compounds. This strain was identified by using a polyphasic approach. The results showed that it should be assigned to the genus Streptomyces. An almost complete 16S rRNA gene sequence of the strain was determined and compared with those of representative Streptomyces species. Strain YIM 33098T was clustered in the same subclade with Streptomyces tendae ATCC19812T and Streptomyces eurythermus ATCC14975T. Similarities of strain YIM 33098T with the two strains were 97.35% and 97.42%, respectively. Based on the phenotypic and genotypic evidence, it is therefore proposed that strain YIM 33098T should be classified in the genus Streptomyces as a new species under the name of Streptomyces nanningensis sp. nov.

Streptomyces roseoalbus sp. nov., an actinomycete isolated from soil in Yunnan, China.

An actinomycete strain was isolated from a soil sample collected from a secondary forest at Yongsheng of Yunnan province, China. The isolate, YIM 31634T, was identified by a polyphasic approach. The 16S rDNA sequence analysis showed that the strain YIM 31634T belongs to the genus Streptomyces, with closest similarity to Streptomyces olivochromogenes DSM 40451T (97.66% similarity). Sequence similarities between strain YIM 31634T and other Streptomyces species in the same subclade ranged from 97.59% (with Streptomyces resistomycificus DSM 40133T) to 97.22% (with Streptomyces mirabilis ATCC 27447T). Key phenotypic characteristics as well as chemotaxonomic features of the actinomyces were congruent with the description of the genus Streptomyces. On the basis of phenotypic and phylogenetic analyses, strain YIM31634T was recognized as a new species of the genus Streptomyces for which the name Streptomyces roseoalbus sp. nov. is proposed. The strain YIM 31634T has been deposited in the Chinese Center of Type Culture Collection as strain CCTCC M 203016T and in the Deutsche Sammlung von Mikroorganismen (DSM 41833T).

Streptomyces yunnanensis sp. nov., a mesophile from soils in Yunnan, China.

A strain was isolated from red soil from the suburb of Kunming in Yunnan, China, during the screening of agricultural antibiotics which prevented and cured wheat-stem rust. This isolate, designated YIM 41004T (= CGMCC 4.1004T = DSM 41793), was identified by a polyphasic approach. The test results suggested that this strain was clearly assigned to the genus Streptomyces and found to be marginally close to Williams cluster 32 based on the morphological and physiological data. The almost-complete 16S rRNA gene sequence of the strain was determined and compared with those of representative streptomycetes. The phylogenetic tree confirmed its membership in the genus Streptomyces and demonstrated that this strain represented a separate phyletic line in a clade encompassed by streptomycetes within cluster 32. Based on the polyphasic evidence, it is therefore proposed that strain YIM 41004T should be classified as Streptomyces yunnanensis sp. nov.