Geodermatophilus ruber sp. nov., isolated from rhizosphere soil of a medicinal plant.

A novel actinobacterial strain, designated CPCC 201356(T), was isolated from a rhizosphere soil sample of the medicinal plant Astragalus membranaceus and subjected to a polyphasic taxonomic analysis. Good growth occurred at 20-32 °C, at pH 7.0-7.5 and with 0-1 % (w/v) NaCl. Colonies on R2A and ISP 2 agar were light red to red, round and lacked aerial mycelium; cells adhered to the agar. The peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. The predominant menaquinones were MK-9(H(4)) and MK-9. Polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine and two unknown phospholipids. The major cellular fatty acids were iso-C(16 : 0), iso-C(15 : 0) and C(17 : 1)ω8c. The G+C content of the genomic DNA was 72.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain CPCC 201356(T) belonged to the family Geodermatophilaceae and consistently formed a distinct sub-branch with Geodermatophilus obscurus DSM 43160(T). The organism showed 16S rRNA gene sequence similarity of 97.7 % with G. obscurus DSM 43160(T). DNA-DNA hybridization between strain CPCC 201356(T) and G. obscurus DSM 43160(T) was 17.4 %. On the basis of evidence from this polyphasic taxonomic study, a novel species, Geodermatophilus ruber sp. nov., is proposed; the type strain is CPCC 201356(T) (=DSM 45317(T) =CCM 7619(T)).

Study of a novel antiosteoporosis screening model targeted on cathepsin K.

OBJECTIVE: To establish an effective assay to access the effects of natural products on cathepsin K for screening antiosteoporosis drugs. METHODS: To obtain the purified cathepsin K, we cloned the target fragment from the mRNA of human osteosacoma cell line MG63 and demonstrated its correctness through DNA sequencing. Cathepsin K was expressed in a high amount in E. coli after IPTG induction, and was purified to near homogenetity through resolution and column purification. The specificity of the protein was shown by Western blotting experiment. The biological activity of the components in the fermentation broth was assayed by their inhibitory effects on cathepsin K and its analog papain. RESULTS: With the inhibition of papain activity as a screen index, the fermentation samples of one thousand strains of fungi were tested and 9 strains among them showed strong inhibitory effects. The crude products of the fermentation broth were tested for their specific inhibitory effects on the purified human cathepsin K, the product of fungi 2358 shows the highest specificity against cathepsin K. CONCLUSIONS: The compounds isolated from fungi 2358 show the highest biological activity and are worth further structure elucidation and function characterization.

Identification of a new peptide deformylase gene from enterococcus faecium and establishment of a new screening model targeted on PDF for novel antibiotics.

OBJECTIVE: To identify a new peptide deformylase (PDF) gene (Genebank Accession AY238515) from Enterococcus faecium and to establish a new screening model targeted on PDF. METHODS: A new PDF gene was identified by BLAST analysis and PCR and was subsequently over-expressed in the prokaryotic expression host E. coli B121(DE3). Over-expressed protein was purified for enzymatic assay by metal affinity chromatography and a new screening model was established for novel antibiotics. RESULT: A new PDF gene of Enterococcus faecium was identified successfully. Ten positive samples were picked up from 8000 compound library and the microbial fermentation broth samples. CONCLUSION: A new PDF of gene Enterococcus faecium was first identified and the model had a high efficacy. Positive samples screened may be antibacterial agents of broad spectrum.