Knockdown of liver cancer cell-secreted exosomal PSMA5 controls macrophage polarization to restrain cancer progression by blocking JAK2/STAT3 signaling.

INTRODUCTION: Tumor-associated macrophages, a major component of the tumor microenvironment, undergo polarization into M2 macrophages (M2), and thereby exert an immunosuppressive effect to induce cancer metastasis. This study strives to uncover a molecular mechanism underlying this event in hepatocellular carcinoma (HCC). METHODS: Proteasome subunit alpha 5 (PSMA5) expression in liver hepatocellular carcinoma (LIHC) tissues and its association with LIHC patients were predicted using StarBase. PSMA5 level in human HCC cells was manipulated via transfection. Exosomes were isolated from HCC cells, and internalized into macrophages which were cocultured with HCC cells. Exosome internalization was observed after fluorescence labeling. HCC cell migration and invasion were evaluated by wound healing and Transwell assays. Xenograft assay was performed to investigate the role of PSMA5 in in vitro tumorigenesis. M2 polarization was assessed by enzyme-linked immunosorbent assay, quantitative reverse transcription polymerase chain reaction, and immunohistochemistry. PSMA5 expression in exosomes and Janus Kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) activation in macrophages and tumors were detected by Western blot analysis. RESULTS: High PSMA5 expression was observed in LIHC tissues and associated with compromised survival of LIHC patients. PSMA5 knockdown inhibited HCC cell migration and invasion. PSMA5 knockdown in HCC cells downregulated PSMA5 level in exosomes from these HCC cells. HCC cell-isolated exosomes were successfully internalized into macrophages, and facilitated M2 polarization and JAK2/STAT3 pathway activation. HCC cell-secreted exosomal PSMA5 knockdown inhibited the exosome-induced effect on macrophages, and attenuated the promotion induced by exosome-treated macrophages on HCC cell migration/invasion and tumorigenesis along with in vivo M2 polarization and JAK2/STAT3 pathway activation. CONCLUSION: HCC cell-secreted exosomal PSMA5 knockdown hinders M2 polarization to suppress cancer progression by restraining JAK2/STAT3 signaling.

Functional Characterization of Small Alarmone Synthetase and Small Alarmone Hydrolase Proteins from Treponema denticola.

The stringent response enables bacteria to survive nutrient starvation, antibiotic challenge, and other threats to cellular survival. Two alarmone (magic spot) second messengers, guanosine pentaphosphate (pppGpp) and guanosine tetraphosphate (ppGpp), which are synthesized by RelA/SpoT homologue (RSH) proteins, play central roles in the stringent response. The pathogenic oral spirochete bacterium Treponema denticola lacks a long-RSH homologue but encodes putative small alarmone synthetase (Tde-SAS, TDE1711) and small alarmone hydrolase (Tde-SAH, TDE1690) proteins. Here, we characterize the respective in vitro and in vivo activities of Tde-SAS and Tde-SAH, which respectively belong to the previously uncharacterized RSH families DsRel and ActSpo2. The tetrameric 410-amino acid (aa) Tde-SAS protein preferentially synthesizes ppGpp over pppGpp and a third alarmone, pGpp. Unlike RelQ homologues, alarmones do not allosterically stimulate the synthetic activities of Tde-SAS. The ~180 aa C-terminal tetratricopeptide repeat (TPR) domain of Tde-SAS acts as a brake on the alarmone synthesis activities of the ~220-aa N-terminal catalytic domain. Tde-SAS also synthesizes "alarmone-like" nucleotides such as adenosine tetraphosphate (ppApp), albeit at considerably lower rates. The 210-aa Tde-SAH protein efficiently hydrolyzes all guanosine and adenosine-based alarmones in a Mn(II) ion-dependent manner. Using a growth assays with a ΔrelAΔspoT strain of Escherichia coli that is deficient in pppGpp/ppGpp synthesis, we demonstrate that Tde-SAS can synthesize alarmones in vivo to restore growth in minimal media. Taken together, our results add to our holistic understanding of alarmone metabolism across diverse bacterial species. IMPORTANCE The spirochete bacterium Treponema denticola is a common component of the oral microbiota. However, it may play important pathological roles in multispecies oral infectious diseases such as periodontitis: a severe and destructive form of gum disease, which is a major cause of tooth loss in adults. The operation of the stringent response, a highly conserved survival mechanism, is known to help many bacterial species cause persistent or virulent infections. By characterizing the biochemical functions of the proteins putatively responsible for the stringent response in T. denticola, we may gain molecular insight into how this bacterium can survive within harsh oral environments and promote infection. Our results also expand our general understanding of proteins that synthesize nucleotide-based intracellular signaling molecules in bacteria.

MicroRNA-1205 Suppresses Hepatocellular Carcinoma Cell Proliferation via a CSNK2B/CDK4 Axis.

Introduction: MicroRNAs (miRNAs) play important roles in the progression of hepatocellular carcinoma (HCC) via modulating expression of their targeting mRNAs. The present study aimed to investigate the role of miR-1205 in HCC cell proliferation and investigate the underlying molecular mechanism. Methods: The effects of miR-1205 on proliferation ability of HCC cell lines were explored in vitro and in vivo. Real-time quantitative PCR (qPCR) analysis was performed to determine miR-1205 expression in HCC tissues and cell lines. Online prediction tools and luciferase assays were used to identify potential target genes of miR-1205. Western blot analysis and dual-luciferase assays were conducted to screen key signaling pathway proteins regulated by miR-1205 and its' target gene. Results: In vitro and in vivo experiments showed that miR-1205 inhibits the proliferation of HCC cells. Dual-luciferase assays showed that miR-1205 interacted with CSNK2B by directly targeting the miRNA-binding site in the CSNK2B sequence, and further qPCR analysis indicated that CSNK2B expression was increased in HCC tissues and negatively correlated with miR-1205 expression. Furthermore, CSNK2B significantly promoted HCC cell proliferation, and CSNK2B overexpression or knockdown attenuated the effects of miR-1205 overexpression or inhibition on HCC cell viability, respectively. Mechanistically, miR-1205 suppresses HCC cell proliferation via a CSNK2B/CDK4 axis. Conclusion: The present results indicated that miR-1205 suppressed HCC cell proliferation by directly targeting CSNK2B and thus inhibiting the CDK4/pRb cell cycle pathway.

A Six-Gene Prognostic Risk Prediction Model In Hepatitis B Virus-Associated Hepatocellular Carcinoma.

Purpose: This study aimed to screen hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC)-related feature ribonucleic acids (RNAs) and to establish a prognostic model. Methods: The transcriptome expression data of HBV-associated HCC were downloaded from The Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus database. Differential RNAs between HBV-associated HCC and normal controls were identified by a meta-analysis of TCGA, GSE55092 and GSE121248. Weighted gene co-expression network analysis was performed to identify key RNAs and modules. A prognostic score model was established using TCGA as a training set by Cox regression analysis and was validated in E-TABM-36 dataset. Additionally, independent prognostic clinical factors were screened, and the function of lncRNAs was predicted through Gene Set Enrichment Analysis. Results: A total of 710 consistent differential RNAs between HBV-associated HCC and normal controls were obtained, including five lncRNAs and 705 mRNAs. An optimized combination of six differential RNAs (DSCR4, DBH, ECM1, GDAP1, MATR3 and RFC4) was selected and a prognostic score model was constructed. Kaplan-Meier analysis demonstrated that the prognosis of the high-risk and low-risk groups separated by this model was significantly different in the training set and the validation set. Gene Set Enrichment Analysis showed that the co-expression genes of DSCR4 were significantly correlated with neuroactive ligand receptor interaction pathway. Conclusion: A prognostic model based on DSCR4, DBH, ECM1, GDAP1, MATR3 and RFC4 was developed that can accurately predict the prognosis of patients with HBV-associated HCC. These genes, as well as histologic grade, may serve as independent prognostic factors in HBV-associated HCC.

Prognostic Score-based Clinical Factors and Metabolism-related Biomarkers for Predicting the Progression of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is a common malignant tumor representing more than 90% of primary liver cancer. This study aimed to identify metabolism-related biomarkers with prognostic value by developing the novel prognostic score (PS) model. Transcriptomic profiles derived from TCGA and EBIArray databases were analyzed to identify differentially expressed genes (DEGs) in HCC tumor samples compared with normal samples. The overlapped genes between DEGs and metabolism-related genes (crucial genes) were screened and functionally analyzed. A novel PS model was constructed to identify optimal signature genes. Cox regression analysis was performed to identify independent clinical factors related to prognosis. Nomogram model was constructed to estimate the predictability of clinical factors. Finally, protein expression of crucial genes was explored in different cancer tissues and cell types from the Human Protein Atlas (HPA). We screened a total of 305 overlapped genes (differentially expressed metabolism-related genes). These genes were mainly involved in "oxidation reduction," "steroid hormone biosynthesis," "fatty acid metabolic process," and "linoleic acid metabolism." Furthermore, we screened ten optimal DEGs (CYP2C9, CYP3A4, and TKT, among others) by using the PS model. Two clinical factors of pathologic stage (P < .001, HR: 1.512 [1.219-1.875]) and PS status (P <.001, HR: 2.259 [1.522-3.354]) were independent prognostic predictors by cox regression analysis. Nomogram model showed a high predicted probability of overall survival time, and the AUC value was 0.837. The expression status of 7 proteins was frequently altered in normal or differential tumor tissues, such as liver cancer and stomach cancer samples.We have identified several metabolism-related biomarkers for prognosis prediction of HCC based on the PS model. Two clinical factors were independent prognostic predictors of pathologic stage and PS status (high/low risk). The prognosis prediction model described in this study is a useful and stable method for novel biomarker identification.

The Clinical Efficacy of Surgical Removal of Hepatocellular Carcinoma in Caudate Lobe in the Chinese Population: A Case-control Study.

Our aims were to compare the therapeutic efficacy of surgical resection of caudate lobe hepatocellular carcinoma and noncaudal lobe hepatocellular carcinoma in the Chinese population. The study group consisted of 220 patients undergoing caudate lobe hepatectomy during the period spanning from January 2003 to November 2017, and 220 patients with caudate lobe hepatectomy were selected as the control group. There were 142 cases (64.5%) of surgical margin of R0 in patients with caudate lobe liver cancer, and 178 cases (80.9%) of surgical margins in patients with noncaudal lobe liver cancer, and the difference was statistically significant (P<0.01) between the 2 groups. Compared with noncaudal lobe liver cancer patients, caudate lobe liver cancer patients had significantly longer operation time (186.65±81.36 vs. 118.85±69.23, P<0.01), longer vessel block time (29.93±11.96 vs. 22.76±10.74, P<0.01), more intraoperative blood loss (709.73±108.39 vs. 329.74±85.76, P<0.01), and there was no significant difference in the incidence of complications (53.4% vs. 46.6%, P>0.05). Significantly different therapeutic efficacy was found between the caudate lobe hepatocellular carcinoma group and the noncaudal lobe hepatocellular carcinoma group, which may be due to the lack of resection margin of caudate-leaf liver cancer surgery and more intraoperative bleeding.

The Ps and Qs of alarmone synthesis in Staphylococcus aureus.

During the stringent response, bacteria synthesize guanosine-3',5'-bis(diphosphate) (ppGpp) and guanosine-5'-triphosphate 3'-diphosphate (pppGpp), which act as secondary messengers to promote cellular survival and adaptation. (p)ppGpp 'alarmones' are synthesized and/or hydrolyzed by proteins belonging to the RelA/SpoT Homologue (RSH) family. Many bacteria also encode 'small alarmone synthetase' (SAS) proteins (e.g. RelP, RelQ) which may also be capable of synthesizing a third alarmone: guanosine-5'-phosphate 3'-diphosphate (pGpp). Here, we report the biochemical properties of the Rel (RSH), RelP and RelQ proteins from Staphylococcus aureus (Sa-Rel, Sa-RelP, Sa-RelQ, respectively). Sa-Rel synthesized pppGpp more efficiently than ppGpp, but lacked the ability to produce pGpp. Sa-Rel efficiently hydrolyzed all three alarmones in a Mn(II) ion-dependent manner. The removal of the C-terminal regulatory domain of Sa-Rel increased its rate of (p)ppGpp synthesis ca. 10-fold, but had negligible effects on its rate of (pp)pGpp hydrolysis. Sa-RelP and Sa-RelQ efficiently synthesized pGpp in addition to pppGpp and ppGpp. The alarmone-synthesizing abilities of Sa-RelQ, but not Sa-RelP, were allosterically-stimulated by the addition of pppGpp, ppGpp or pGpp. The respective (pp)pGpp-synthesizing activities of Sa-RelP/Sa-RelQ were compared and contrasted with SAS homologues from Enterococcus faecalis (Ef-RelQ) and Streptococcus mutans (Sm-RelQ, Sm-RelP). Results indicated that EF-RelQ, Sm-RelQ and Sa-RelQ were functionally equivalent; but exhibited considerable variations in their respective biochemical properties, and the degrees to which alarmones and single-stranded RNA molecules allosterically modulated their respective alarmone-synthesizing activities. The respective (pp)pGpp-synthesizing capabilities of Sa-RelP and Sm-RelP proteins were inhibited by pGpp, ppGpp and pppGpp. Our results support the premise that RelP and RelQ proteins may synthesize pGpp in addition to (p)ppGpp within S. aureus and other Gram-positive bacterial species.

Crucial lncRNAs associated with adipocyte differentiation from human adipose-derived stem cells based on co-expression and ceRNA network analyses.

BACKGROUND: Injection of adipose-derived stem cells (ASCs) is a promising treatment for facial contour deformities. However, its treatment mechanisms remain largely unknown. The study aimed to explain the molecular mechanisms of adipogenic differentiation from ASCs based on the roles of long noncoding RNAs (lncRNAs). METHODS: Datasets of mRNA-lncRNA (GSE113253) and miRNA (GSE72429) expression profiling were collected from Gene Expression Omnibus database. The differentially expressed genes (DEGs), lncRNAs (DELs) and miRNAs (DEMs) between undifferentiated and adipocyte differentiated human ASCs were identified using the Linear Models for Microarray Data method. DELs related co-expression and competing endogenous RNA (ceRNA) networks were constructed. Protein-protein interaction (PPI) analysis was performed to screen crucial target genes. RESULTS: A total of 748 DEGs, 17 DELs and 51 DEMs were identified. A total of 13 DELs and 279 DEGs with Pearson correlation coefficients > 0.9 and p-value < 0.01 were selected to construct the co-expression network. A total of 151 interaction pairs among 112 nodes (10 DEMs; eight DELs; 94 DEGs) were obtained to construct the ceRNA network. By comparing the lncRNAs and mRNAs in two networks, five lncRNAs (SNHG9, LINC02202, UBAC2-AS1, PTCSC3 and myocardial infarction associated transcript (MIAT)) and 32 genes (i.e., such as phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1), protein tyrosine phosphatase receptor type B (PTPRB)) were found to be shared. PPI analysis demonstrated PIK3R1 , forkhead box O1 (FOXO1; a transcription factor) and estrogen receptor 1 (ESR1) were hub genes, which could be regulated by the miRNAs that interacted with the above five lncRNAs, such as LINC02202-miR-136-5p-PIK3R1, LINC02202-miR-381-3p-FOXO1 and MIAT-miR-18a-5p-ESR1. LINC02202 also could directly co-express with PIK3R1. Furthermore, PTPRB was predicted to be modulated by co-expression with LINC01119. CONCLUSION: MIAT, LINC02202 and LINC01119 may be potentially important, new lncRNAs associated with adipogenic differentiation of ASCs. They may be involved in adipogenesis by acting as a ceRNA or co-expressing with their targets.

Elevated pre-existing lymphocytic infiltrates in tumour stroma predict poor prognosis in resectable urothelial carcinoma of the bladder.

AIMS: Lymphocytic infiltrates are predominantly distributed in the tumour stroma, and represents the tumour-related immune response. The aim of this study was to elucidate the prognostic value of stromal lymphocytic infiltrates (SLI) in resectable urothelial carcinoma of the bladder (UCB). METHODS AND RESULTS: The prognostic significance of SLI in UCB was assessed in a discovery cohort (n = 226; 60 deaths) and in a validation cohort (n = 417; 103 deaths). SLI was categorised into intense (≥50% SLI) and non-intense (<50% SLI). A multivariable Cox model was used to analyse the associations of SLI score with overall survival (OS) and disease-free survival. Immunofluorescence staining was used to examine the composition and phenotypes of SLI. The median follow-up times were 58.1 and 64.9 months in the discovery and validation cohorts, respectively. SLI was intense in 38.1% of patients in the discovery cohort and in 20.9% of patients in the validation cohort (P < 0.001). SLI score had independent prognostic value for OS [hazard ratio (HR) 2.132; P = 0.016] and disease-specific survival (DSS) (HR 1.952; P = 0.04) in the discovery cohort, which was confirmed in the validation cohort (OS: HR 1.636; P = 0.023; DSS: HR 1.627; P = 0.029). SLI score was positively associated with histological grade, tumour stage and lymph node status in both cohorts. Moreover, in the stroma, SLI displayed a broad spectrum of inhibitory immune cells, by expressing several major immune checkpoint molecules, i.e. programmed cell death protein 1, programmed death-ligand 1, indoleamine 2,3-dioxygenase, and T-cell immunoglobulin and mucin domain 3. CONCLUSION: Intense pre-existing SLI was validated as a reliable marker of poorer prognosis for survival in UCB patients, which may add to the prognostic significance of the TNM classification.

Heterogeneous nuclear ribonucleoprotein K is associated with poor prognosis and regulates proliferation and apoptosis in bladder cancer.

Heterogeneous nuclear ribonucleoprotein K (hnRNPK) is an essential RNA- and DNA-binding protein that regulates diverse biological events, especially DNA transcription. hnRNPK overexpression is related to tumorigenesis in several cancers. However, both the expression patterns and biological mechanisms of hnRNPK in bladder cancer are unclear. We investigated hnRNPK expression by immunohistochemistry in 188 patients with bladder cancer, and found that hnRNPK expression levels were significantly increased in bladder cancer tissues and that high-hnRNPK expression was closely correlated with poor prognosis. Loss- and gain-of-function assays demonstrated that hnRNPK promoted proliferation, anti-apoptosis, and chemoresistance in bladder cancer cells in vitro, and hnRNPK knockdown suppressed tumorigenicity in vivo. Mechanistically, hnRNPK regulated various functions in bladder cancer by directly mediating cyclin D1, G0/G1 switch 2 (G0S2), XIAP-associated factor 1, and ERCC excision repair 4, endonuclease catalytic subunit (ERCC4) transcription. In conclusion, we discovered that hnRNPK plays an important role in bladder cancer, suggesting that it is a potential prognostic marker and a promising target for treating bladder cancer.

Harnessing the potential of halogenated natural product biosynthesis by mangrove-derived actinomycetes.

Mangrove-derived actinomycetes are promising sources of bioactive natural products. In this study, using homologous screening of the biosynthetic genes and anti-microorganism/tumor assaying, 163 strains of actinomycetes isolated from mangrove sediments were investigated for their potential to produce halogenated metabolites. The FADH2-dependent halogenase genes, identified in PCR-screening, were clustered in distinct clades in the phylogenetic analysis. The coexistence of either polyketide synthase (PKS) or nonribosomal peptide synthetase (NRPS) as the backbone synthetases in the strains harboring the halogenase indicated that these strains had the potential to produce structurally diversified antibiotics. As a validation, a new enduracidin producer, Streptomyces atrovirens MGR140, was identified and confirmed by gene disruption and HPLC analysis. Moreover, a putative ansamycin biosynthesis gene cluster was detected in Streptomyces albogriseolus MGR072. Our results highlight that combined genome mining is an efficient technique to tap promising sources of halogenated natural products synthesized by mangrove-derived actinomycetes.

Identification of two novel anti-fibrotic benzopyran compounds produced by engineered strains derived from Streptomyces xiamenensis M1-94P that originated from deep-sea sediments.

The benzopyran compound obtained by cultivating a mangrove-derived strain, Streptomyces xiamenensis strain 318, shows multiple biological effects, including anti-fibrotic and anti-hypertrophic scar properties. To increase the diversity in the structures of the available benzopyrans, by means of biosynthesis, the strain was screened for spontaneous rifampicin resistance (Rif), and a mutated rpsL gene to confer streptomycin resistance (Str), was introduced into the S. xiamenensis strain M1-94P that originated from deep-sea sediments. Two new benzopyran derivatives, named xiamenmycin C (1) and D (2), were isolated from the crude extracts of a selected Str-Rif double mutant (M6) of M1-94P. The structures of 1 and 2 were identified by analyzing extensive spectroscopic data. Compounds 1 and 2 both inhibit the proliferation of human lung fibroblasts (WI26), and 1 exhibits better anti-fibrotic activity than xiamenmycin. Our study presents the novel bioactive compounds isolated from S. xiamenensis mutant strain M6 constructed by ribosome engineering, which could be a useful approach in the discovery of new anti-fibrotic compounds.

Modestobacter marinus sp. nov., a psychrotolerant actinobacterium from deep-sea sediment, and emended description of the genus Modestobacter.

The taxonomic status of an actinobacterium that changed colour during growth, strain 42H12-1(T), isolated from deep-sea sediment collected from the Atlantic Ocean, was established using a combination of genotypic and phenotypic data. Strain 42H12-1(T) formed a distinct branch in the 16S rRNA gene phylogenetic tree together with the type strains in the genus Modestobacter. The highest sequence similarity by blast analysis was to Modestobacter versicolor CP153-2(T) (98.5 %) and the second-highest sequence similarity was to Modestobacter multiseptatus AA-826(T) (97.5 %). DNA-DNA relatedness of only 12 % (sd 1.82 %) between strain 42H12-1(T) and M. versicolor DSM 16678(T) differentiated them as members of separate genomic species. Colonies of strain 42H12-1(T) were black on oligotrophic medium, but orange to red, turning black, on copiotrophic medium. The peptidoglycan contained meso-diaminopimelic acid. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and an unknown aminophospholipid. The predominant menaquinone was MK-9(H(4)). The major fatty acids were iso-C(16 : 0) and C(17 : 1)ω8c. The DNA G+C content was 72.3±1 mol%. Strain 42H12-1(T) ( = DSM 45201(T)  = CGMCC 4.5581(T)) is assigned as the type strain of a novel species of the genus Modestobacter, for which the name Modestobacter marinus sp. nov. is proposed.

Serinicoccus profundi sp. nov., an actinomycete isolated from deep-sea sediment, and emended description of the genus Serinicoccus.

A Gram-reaction-positive bacterial strain of the genus Serinicoccus, designated MCCC 1A05965(T), was isolated from a deep-sea (5368 m) sediment of the Indian Ocean. Comparison of 16S rRNA gene sequences revealed that the isolate shared 97.6 % sequence similarity with Serinicoccus marinus JC1078(T), the type strain of the only described species of the genus Serinicoccus. The DNA-DNA relatedness between these two strains was 46.2 % (standard deviation 1.86 %). The cell wall contained alanine, glycine, serine, l-ornithine and glutamic acid, which corresponds to the description of the genus Serinicoccus. The acyl type of the glycan chain of the peptidoglycan was glycolyl. Other characteristics of strain MCCC 1A05965(T) were consistent with those of the genus Serinicoccus. Cells were coccoid, moderately halophilic, oxidase-negative, catalase-positive and non-spore-forming. The major menaquinone was MK-8(H(4)). The predominant cellular fatty acids were iso-C(15 : 0) (34.7 %) and iso-C(16 : 0) (17.0 %). The polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, phosphatidylinositol and an unknown glycolipid. The DNA G+C content was 72 mol%. Strain MCCC 1A05965(T) (=0714S6-1(T) =DSM 21363(T) =CGMCC 4.5582(T)) is assigned as the type strain of a novel species, for which the name Serinicoccus profundi sp. nov. is proposed.

Streptomyces indicus sp. nov., an actinomycete isolated from deep-sea sediment.

The taxonomic position of an actinomycete isolated from deep-sea sediment from the Indian Ocean was determined by using a polyphasic approach. The presence of iso-C(15 : 0), anteiso-C(15 : 0), iso-C(16 : 0), iso-C(17 : 0) and anteiso-C(17 : 0) as the major cellular fatty acids, ll-diaminopimelic acid as the characteristic diamino acid, and MK-9(H(4), H(6) and H(8)) as the major menaquinones supported the affiliation of strain IH32-1(T) to the genus Streptomyces. Comparison of 16S rRNA gene sequences showed that strain IH32-1(T) exhibited highest similarities to the type strains of Streptomyces globosus (97.6 %) and Streptomyces toxytricini (97.6 %). However, DNA-DNA relatedness values between strain IH32-1(T) and the type strains of S. globosus and S. toxytricini were determined as 55.2 ± 4.7 and 38.3 ± 2.5 %, respectively. Based on its chemotaxonomic, phenotypic and genotypic characteristics, strain IH32-1(T) is considered to represent a novel species in the genus Streptomyces, for which the name Streptomyces indicus sp. nov. is proposed. The type strain is IH32-1(T) ( = DSM 42001(T) = CGMCC 4.5727(T)).

[Advance in microbial ribosome engineering].

Drug-resistance mutation of microorganisms reflects structure and function changes of the ribosome and RNA polymerase. These changes can have significant effects on secondary metabolism in the mutant strain. Thus, ribosome engineering is an effective approach to develop mutant strains that overproduce secondary metabolites (i. e. antibiotics) by screening various drug-resistance mutations. We introduced the concept and the mechanisms of the ribosome engineering. The efficacy of the strain improvement was highlighted in Streptomyces spp. by introducing combinatory drug-resistances. The applications of the method in the strain-breeding of various bacteria were also summarized.

Streptomyces avicenniae sp. nov., a novel actinomycete isolated from the rhizosphere of the mangrove plant Avicennia mariana.

A novel isolate, designated strain MCCC 1A01535(T), belonging to the genus Streptomyces was isolated from the rhizosphere of the mangrove plant Avicennia mariana from Fujian Province, south China. Characterization of the isolate was based on a polyphasic approach. Pairwise comparison of 16S rRNA gene sequences revealed that strain MCCC 1A01535(T) shared 97.7 and 97.5 % sequence similarities to Streptomyces specialis GW41-1564(T) and Streptomyces hainanensis YIM47672(T), respectively, its most closely related neighbours, whereas the DNA-DNA relatedness value between strains MCCC 1A01535(T) and GW41-1564(T) was 50.2 %. The major fatty acids of strain MCCC 1A01535(T) were iso-C(16 : 0), C(16 : 0) and anteiso-C(15 : 0). These differed from the fatty acid compositions of related strains. Strain MCCC 1A01535(T) exhibited an unusual menaquinone system that comprised MK-10(H(6)) as the predominant component and moderate amounts of MK-9(H(6)), MK-9(H(8)) and MK-10(H(8)); minor amounts of MK-9(H(4)), MK-10(H(4)), MK-9(H(10)) and MK-10(H(10)) were also present. Based on its chemotaxonomic, phenotypic and genotypic characteristics, strain MCCC 1A01535(T) is considered to represent a novel species of the genus Streptomyces, for which the name Streptomyces avicenniae sp. nov. is proposed. The type strain is MCCC 1A01535(T) (=DSM 41943(T)=CGMCC 4.5510(T)).

Nerve growth factor-mediated paracrine regulation of hepatic stellate cells by multipotent mesenchymal stromal cells.

AIMS: Multipotent mesenchymal stromal cells (MSC) have been reported to prevent the development of liver fibrosis and have emerged as a promising strategy for cell-based therapy. However, the underlying therapeutic mechanism remains unclear. Hepatic stellate cells (SC) activation is a pivotal event in the development of liver fibrosis. MAIN METHODS: We hypothesized that MSC play an important role in regulating SC proliferation and apoptosis through paracrine mechanisms. To investigate the paracrine interactions between MSC and SC, a co-culture experimental model was developed using human MSC (hMSC) and human SC (hSC). KEY FINDINGS: We demonstrate that hMSC and hSC both express nerve growth factor (NGF) receptor p75. Results acquired from transwell co-culture experiments using hSC and hMSC showed that hMSC secrete NGF, which enhances hSC apoptosis. Transcription factor nuclear factor kappa B (NF-KappaB) and B cell leukemia-xl (Bcl-xl) take part in the process. SIGNIFICANCE: These findings demonstrated that hMSC indirectly modulate activated hSC in vitro via NGF-mediated signaling cascades and provide a potential mechanism of how transplanted MSC are effective in treating liver fibrosis.

Streptomyces xiamenensis sp. nov., isolated from mangrove sediment.

Actinomycete strain MCCC 1A01550(T), isolated from the national mangrove reserve in Fujian Province, China, was determined to belong to the genus Streptomyces based on a polyphasic approach. The cell wall of the novel strain contained ll-diaminopimelic acid and galactose. The predominant menaquinones were MK-9(H(4)) and MK-9(H(6)) and the major fatty acids were iso-C(16 : 0), cis9-C(16 : 1) and C(16 : 0). The diagnostic phospholipid was phosphatidylethanolamine. The DNA G+C content of the novel strain was 71.6 mol%. Phylogenetic analysis of 16S rRNA gene sequences confirmed the separation of the novel strain from recognized members of the genus Streptomyces available in public databases. DNA-DNA relatedness values between strain MCCC 1A01550(T) and the type strains of three related species ranged from 21.29 % to 43.38 %. Based on its phenotypic and genotypic characteristics, strain MCCC 1A01550(T) (=DSM 41903(T)=CGMCC 4.3534(T)) represents the type strain of a novel species, for which the name Streptomyces xiamenensis sp. nov. is proposed.