miR-135b-5p Suppresses Androgen Receptor-Enhanced Hepatocellular Carcinoma Cell Proliferation via Regulating the HIF-2α/c-Myc/P27 Signals in vitro.

INTRODUCTION: Hepatocellular carcinoma (HCC) accounts for more than 90% of liver cancers and is ranked as the fifth most common malignancy. Androgen receptor (AR) may promote the progression of HCC at an early stage of the disease. However, this study identified miR-135b-5p as an AR upstream regulator can suppress AR protein expression and inhibit HCC proliferation, consistent with the idea that AR expression is negatively correlated with HCC progression. METHODS: The target microRNAs were predicted using online databases (TargetScan, miRDB, and MicroCosm Targets). Cell proliferation ability was measured by MTT and colony formation assay. Western blot was performed to analyze the expression levels of AR, HIF-2α, c-Myc, and p27, which are related to HCC proliferation. Chromatin immunoprecipitation (ChIP) assay and luciferase reporter assay were carried out to investigate the mechanism by which miR-135b-5p decreases AR expression. RESULTS: miR-135b-5p suppresses HCC cell proliferation and AR expression. Downregulation of AR expression by miR-135b-5p may in turn transcriptionally modulate HIF-2α expression via direct binding of AR to the androgen response element (ARE) in the HIF-2α promoter. Further dissection of the mechanism revealed that AR-modulated HIF-2α could suppress c-Myc expression resulting in increased p27 expression that likely contributes to the suppression of proliferation in HCC cells. CONCLUSION: miR-135b-5p suppresses HCC cell proliferation via targeting AR-modulated HIF-2α/c-Myc/p27 signals, which may help to develop more effective therapies to prevent HCC progression.

Strepchazolins A and B: Two New Alkaloids from a Marine Streptomyces chartreusis NA02069.

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.

Pseudonocardia nematodicida sp. nov., isolated from mangrove sediment in Hainan, China.

Two aerobic, Gram-stain positive actinobacterial strains with nematicidal activity, designated HA11164(T) and HA12591, were isolated from mangrove sediments in Hainan, China. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that strains HA11164(T) and HA12591 belong to the genus Pseudonocardia and are closely related to Pseudonocardia carboxydivorans (with the similarities of 98.30 and 98.24 %, respectively), Pseudonocardia alni (98.23 and 98.16 %, respectively) and Pseudonocardia antimicrobica (98.10 and 98.03 %, respectively). The major polar lipids of the strain HA11164(T), as a representative strain of the two strains, were found to consist of phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, five unidentified glycolipids and four unidentified polar lipids. The predominant menaquinone of strain HA11164(T) was identified as MK-8 (H4), and the major fatty acids were identified as iso-C16:0, C17:1 ω10, C16:0 and C16:1 ω9. The G+C content of strain HA11164(T) was determined to be 74.9 mol%. The DNA-DNA relatedness values between strains HA11164(T) and P. alni, Pseudonocardia tropica, Pseudonocardia antarctica, P. carboxydivorans and Pseudonocardia parietis were 58.3, 56.2, 50.0, 57.1 and 46.0 %, respectively. Based on the results of this polyphasic study, strains HA11164(T) and HA12591 are considered to represent a novel species of the genus Pseudonocardia, for which the name Pseudonocardia nematodicida sp. nov. is proposed. The type strain is HA11164(T) (=CGMCC 4.7118(T) = DSM 45940(T)).

Nocardiopsis mangrovei sp. nov., isolated from mangrove sediment.

Two Gram-positive actinobacterial strains, designated HA11166(T) and HA12420, were isolated from mangrove sediments in Hainan, China. The bacterial cells grew with 0-9 % (w/v) NaCl, at 15-40 °C and pH 5.0-10.0, with the optimum growth at 1 % NaCl, 30-37 °C and pH 7.0. The organisms had a range of chemical and morphological properties consistent with their classification in the genus Nocardiopsis. Phylogenetic analysis of the 16S rRNA gene sequences indicated that strains HA11166(T) and HA12420 can be affiliated to the genus Nocardiopsis and most closely related to Nocardiopsis trehalosi VKM Ac-942(T) (with the similarity of 97.2 and 97.5 %, respectively). The value of DNA-DNA relatedness between type strain HA11166(T), selected as the representative strain, and N. trehalosi VKM Ac-942(T) was 38.8 %. The DNA G+C content of strain HA11166(T) was 73.7 %. On the basis of these phenotypic and genotypic data, strains HA11166(T) and HA12420 are proposed to represent a novel species of the genus Nocardiopsis, for which the name Nocardiopsis mangrovei sp. nov. is proposed. The type strain is HA11166(T) (=CGMCC 4.7119(T)=DSM 46665(T)).

Gracilibacillus marinus sp. nov., isolated from the northern South China Sea.

Two gram-positive, aerobic, spore-forming, rod-shaped bacteria, designated HB09003(T) and HB12160, were isolated from seawater and sediment in the northern South China Sea, respectively. Cells were found to be motile by means of peritrichous flagella. The strains were found to grow with 0-15 % (w/v) NaCl, at 10-45 °C and pH 5.0-10.7, with an optimum of 3 % NaCl, 28 °C and pH 8.5, respectively. The predominant isoprenoid quinone of strain HB09003(T), selected as the representative strain, was identified as MK-7. This strain was found to possess anteiso-C15:0, iso-C15:0, anteiso-C17:0 and C16:0 as the major fatty acids. The G+C contents of strain HB09003(T) and HB12160 were determined to be 34.1 and 34.3 mol%, respectively. Analysis of the 16S rRNA gene sequences of the two strains showed an affiliation with the genus Gracilibacillus, with Gracilibacillus kekensis CGMCC 1.10681(T) (similarity of 97.4, 98.0 %, respectively) and Gracilibacillus ureilyticus CGMCC 1.7727(T) (similarity of 97.1, 97.8 %, respectively) as their closest relatives. The DNA-DNA hybridization values between strain HB09003(T) and the two type strains were 42.2 and 54.1 %, respectively. On the basis of phenotypic and genotypic data, strain HB09003(T) and HB12160 are proposed to represent a novel species of the genus Gracilibacillus, for which the name Gracilibacillus marinus sp. nov. is proposed. The type strain is HB09003(T) (=CGMCC 1.10343(T) = DSM 23372(T)).

A new diterpenoid from Rhizophora apiculata.

A new diterpenoid, 15(S)-isopimar-7-en-1-oxo-15,16-diol (1), was isolated from the stems of mangrove plant Rhizophora apiculata. The structure of the new compound was elucidated by MS, IR, 1D, and 2D NMR techniques, including HMQC, HMBC, and NOESY correlations. In addition, seven known constituents were isolated from this plant for the first time.

[Seven kinds of new SCCmec type in Methicillin-resistant Staphyloccus aureus and their susceptibility to the antibiotics].

In order to explore the resistance and the staphylococcal chromosome cassette mec (SCCmec) types of Methicillin-resistant S. aureus (MRSA) in the area of Haikou, 686 strains of MRSA had been distinguished from 1174 strains of S. aureus using PBP2a testing. The resistance to the seven deputies of seven kinds antibiotics which in common use in clinic, including Oxacillin, Vancomycin, Doxycyclin, Amikacin, Erythromycin, Chloramphenicol, Ciprofloxacin, and SCCmec type of 58 strains had been tested using the K-B Agar diffuse, E-test and multiplex PCR strategy, and seven kinds of new SCCmec types were found in 17 strains. Their specialties of structure are: type-new3 possess four loci of A, F, H, M; New4 possess three loci of F, H, M; New5 possess three loci of D, B, M; New6 possess three loci of A, B, M; New7 possess four loci of H, E, C, M; New8 possess two loci of A, M; New9 possess three loci of A, C, M. All of them are different from the types reported. The strains carrying new SCC mec types are different from that carrying old SCC mec types in the epidemical distribution and resistance to the antibiotics: they were mostly isolated from the out-patients and have high level and wider range of resistance to antibiotics and deserve to pay more attention.

[Two kinds of new Sccmec type in Methicillin-resistant Staphylococcus aureus and their susceptibility to the antibiotics].

In order to explore the resistance, epidemical distribution and the staphylococcal chromosome cassette mec (SCCmec) types of Methicillin-resistant S. aureus (MRSA) in the area of Haikou, the resistance and SCCmec type of MRSA isolated from clinical sample has been tested using the K-B Agar diffuse, E-test and multiplex PCR strategy, resulting that two kinds of new SCC mec types were found in them. Type-newl possess three loci of B, M, F. Locus M, which locate in mecA, is the indicator of mecA, and also used as the positive control. Locus B, which locate in upstream of mec A, is specific for type- II and F, which locate in downstream of mec A, is specific for type- iU ; and so, type-newl was combined from the type- II and - I . Type-new2 possess five loci of A, B, M, F, H. Locus A, which is locate in upstream of mecA, is specific for type- I and H, which is locate in downstream of mecA, is also specific for type- 1 ; and so, type-new2 was combined from the type- I , - II and - I . The strains carrying new SCC mec types are different from that carrying old SCC mec types in the epidemical distribution and resistance to the antibiotics. They can be usually isolated from the out-patients and have high level and wider range of resistance to antibiotics. It must be paid more attention to them.

[Archaeal diversity associated with sponge Pachychalina sp. analyzed by culture-independent approach].

With culture-independent approach, microbial total DNA was directly extracted from Pachychalina sp. Using the total microbial DNA as template, archaeal 16S rDNAs were amplified by PCR with universal primers. Amplified products were cloned into T-vector and secondarily amplified by PCR. Then the secondarily amplified products were purified to be further characterized by termed ARDRA (amplified rDNA restriction analysis). According to the enzyme restriction mapping, the apparent difference among them were disclosed. Furthermore eight archaeal cloned partial sequences were acquired and built up a phylogenetic tree. In the phylogenetic tree, the eight archaea belonged to Methanogenium organophilum and Methanoplanus petrolearius, but the 16S rDNAs similarities among them and those archaea registered in RDP Database didn't excess to 90%. It means that they maybe represent some novel archaeal groups.