Genome Analysis of Multiple Polysaccharide-Degrading Bacterium Microbulbifer thermotolerans HB226069: Determination of Alginate Lyase Activity.

Polysaccharide-degrading bacteria are key participants in the global carbon cycle and algal biomass recycling. Herein, a polysaccharide lyase-producing strain HB226069 was isolated from Sargassum sp. from Qingge Port, Hainan, China. Results of the phylogenetic of the 16S rRNA gene and genotypic analysis indicated that the isolate should be classified as Microbulbifer thermotolerans. The whole genome is a 4,021,337 bp circular chromosome with a G+C content of 56.5%. Analysis of the predicted genes indicated that strain HB226069 encoded 161 carbohydrate-active enzymes (CAZymes), and abundant putative enzymes involved in polysaccharide degradation were predicted, including alginate lyase, fucosidase, agarase, xylanase, cellulase, pectate lyase, amylase, and chitinase. Three of the putative polysaccharide lyases from PL7 and PL17 families were involved in alginate degradation. The alginate lyases of strain HB226069 showed the maximum activity of 117.4 U/mL at 50 °C, pH 7.0, and 0.05 M FeCl3, while exhibiting the best stability at 30 °C and pH 7.0. The Thin Layer Chromatography (TLC) and Electrospray Ionization Mass Spectrometry (ESI-MS) analyses indicated that the alginate oligosaccharides (AOSs) degraded by the partially purified alginate lyases contained oligosaccharides of DP2-DP5 and monosaccharide while reacting for 36 h. The complete genome of M. thermotolerans HB226069 enriches our understanding of the mechanism of polysaccharide lyase production and supports its potential application in polysaccharide degradation.

Genome Analysis of a Novel Polysaccharide-Degrading Bacterium Paenibacillus algicola and Determination of Alginate Lyases.

Carbohydrate-active enzymes (CAZymes) are an important characteristic of bacteria in marine systems. We herein describe the CAZymes of Paenibacillus algicola HB172198T, a novel type species isolated from brown algae in Qishui Bay, Hainan, China. The genome of strain HB172198T is a 4,475,055 bp circular chromosome with an average GC content of 51.2%. Analysis of the nucleotide sequences of the predicted genes shows that strain HB172198T encodes 191 CAZymes. Abundant putative enzymes involved in the degradation of polysaccharides were identified, such as alginate lyase, agarase, carrageenase, xanthanase, xylanase, amylases, cellulase, chitinase, fucosidase and glucanase. Four of the putative polysaccharide lyases from families 7, 15 and 38 were involved in alginate degradation. The alginate lyases of strain HB172198T exhibited the maximum activity 152 U/mL at 50 °C and pH 8.0, and were relatively stable at pH 7.0 and temperatures lower than 40 °C. The average degree of polymerization (DP) of the sodium alginate oligosaccharide (AOS) degraded by the partially purified alginate lyases remained around 14.2, and the thin layer chromatography (TCL) analysis indicated that it contained DP2-DP8 oligosaccharides. The complete genome sequence of P. algicola HB172198T will enrich our knowledge of the mechanism of polysaccharide lyase production and provide insights into its potential applications in the degradation of polysaccharides such as alginate.

Exendin-4 may improve type 2 diabetes by modulating the epigenetic modifications of pancreatic histone H3 in STZ-induced diabetic C57BL/6 J mice

Type 2 diabetes (T2D) is a complicated systemic disease that might be improved by exendin-4, although the epigenetic role remains unclear. In the current study, C57BL/6 J mice were used to generate a T2D model, followed by treatment with exendin-4 (10 μg/kg). Histone H3K9 and H3K23 acetylation, H3K4 mono-methylation, and H3K9 di-methylation were explored by western blot analysis of pancreatic histone extracts. Real-time polymerase chain reaction (PCR) was used to examine the expression levels of pancreatic beta cell development-related genes, and chromatin immunoprecipitation (ChIP) was applied to analyze H3 and H3K9 acetylation, H3K4 mono-methylation, and H3K9 di-methylation in the promoter region of the pancreatic and duodenal homeobox 1 (Pdx1) gene. The results showed that total H3K9 di-methylation and H3K9 and H3K23 acetylation increased in pancreatic tissues of diabetic mice, whereas H3K4 mono-methylation was reduced. All of these changes could be abrogated by treatment with exendin-4. Our data indicated that T2D progression might be improved by exendin-4 treatment through the reversal of global pancreatic histone H3K9 and H3K23 acetylation, H3K4 mono-methylation, and H3K9 di-methylation. A better understanding of these epigenetic alterations may, therefore, lead to novel therapeutic strategies for T2D. (AU)

Exendin-4 may improve type 2 diabetes by modulating the epigenetic modifications of pancreatic histone H3 in STZ-induced diabetic C57BL/6 J mice.

Type 2 diabetes (T2D) is a complicated systemic disease that might be improved by exendin-4, although the epigenetic role remains unclear. In the current study, C57BL/6 J mice were used to generate a T2D model, followed by treatment with exendin-4 (10 µg/kg). Histone H3K9 and H3K23 acetylation, H3K4 mono-methylation, and H3K9 di-methylation were explored by western blot analysis of pancreatic histone extracts. Real-time polymerase chain reaction (PCR) was used to examine the expression levels of pancreatic beta cell development-related genes, and chromatin immunoprecipitation (ChIP) was applied to analyze H3 and H3K9 acetylation, H3K4 mono-methylation, and H3K9 di-methylation in the promoter region of the pancreatic and duodenal homeobox 1 (Pdx1) gene. The results showed that total H3K9 di-methylation and H3K9 and H3K23 acetylation increased in pancreatic tissues of diabetic mice, whereas H3K4 mono-methylation was reduced. All of these changes could be abrogated by treatment with exendin-4. Our data indicated that T2D progression might be improved by exendin-4 treatment through the reversal of global pancreatic histone H3K9 and H3K23 acetylation, H3K4 mono-methylation, and H3K9 di-methylation. A better understanding of these epigenetic alterations may, therefore, lead to novel therapeutic strategies for T2D.

Mangrovicoccus algicola sp. nov., an alginate lyase - producing marine bacterium.

A Gram-stain-negative, non-motile, ellipsoid bacterium, designated HB182678T, was isolated from brown alga collected from Hainan province, PR China. Growth was observed at 10-50 °C (optimum 37-40 °C), at pH 6-10 (optimum pH 8) and in the presence of 0.5-13% (w/v) NaCl (optimum, 2-4%). The predominant isoprenoid quinone was Q-10 and the major fatty acids were C18 : 1 ω7c, C16 : 0, C18 : 0 and C19 : 0 cyclo ω8c. The polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, an unidentified phospholipid, two unidentified glycolipids and three unidentified aminophospholipids. The size of the draft genome was 4.40 Mbp with G+C content 68.8 mol%. Phylogenetic analysis of 16S rRNA gene sequence indicated that strain HB182678T belonged to the genus Mangrovicoccus, and the closest phylogenetically related species was Mangrovicoccus ximenensis T1lg56T (with the similarity of 96.3%). Whole genome average nucleotide identity (ANI) value between them was 84.3% and in silico DNA-DNA hybridization value was 27.2%. The combined phylogenetic relatedness, phenotypic and genotypic features supported the conclusion that strain HB182678T represents a novel species of the genus Mangrovicoccus, for which the name Mangrovicoccus algicola sp. nov. is proposed. The type strain is HB182678T (=MCCC 1K04624T=KCTC 82318T).

TGF-ß1 Induces Immune Escape by Enhancing PD-1 and CTLA-4 Expression on T Lymphocytes in Hepatocellular Carcinoma.

Primary liver cancer (PLC) is one of the most common types of cancer worldwide. Hepatocellular carcinoma (HCC) accounts for approximately 90% of PLC cases. The HCC microenvironment plays an important role in the occurrence and development of HCC. Immunotherapy for the HCC microenvironment has become an effective treatment strategy. T lymphocytes are an important part of the HCC microenvironment, and programmed cell death 1 (PD-1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) are the main immunosuppressive molecules of T lymphocytes. Transforming growth factor ß1 (TGF-ß1) can inhibit the immune function of T lymphocytes and promote the occurrence and development of tumors. However, few studies have explored whether TGF-ß1 can upregulate the expression of PD-1 and CTLA-4 on T cells. In this study, we showed that TGF-ß1 upregulated the expression of PD-1 and CTLA-4 on T lymphocytes and attenuated the cytotoxicity of T lymphocytes for HCC cells in vitro and in vivo. In addition, TGF-ß1 increased the apoptosis of T lymphocytes induced by HCC cells. Finally, we found that the mechanism by which TGF-ß1 upregulates the expression of PD-1 and CTLA-4 on T lymphocytes may be related to the calcineurin-nuclear factor of activated T cells 1 (CaN/NFATc1) pathway. This study will provide some experimental basis for liver cancer immunotherapy based on the tumor microenvironment.

Identification of polycistronic transcriptional units and non-canonical introns in green algal chloroplasts based on long-read RNA sequencing data.

BACKGROUND: Chloroplasts are important semi-autonomous organelles in plants and algae. Unlike higher plants, the chloroplast genomes of green algal linage have distinct features both in organization and expression. Despite the architecture of chloroplast genome having been extensively studied in higher plants and several model species of algae, little is known about the transcriptional features of green algal chloroplast-encoded genes. RESULTS: Based on full-length cDNA (Iso-Seq) sequencing, we identified widely co-transcribed polycistronic transcriptional units (PTUs) in the green alga Caulerpa lentillifera. In addition to clusters of genes from the same pathway, we identified a series of PTUs of up to nine genes whose function in the plastid is not understood. The RNA data further allowed us to confirm widespread expression of fragmented genes and conserved open reading frames, which are both important features in green algal chloroplast genomes. In addition, a newly fragmented gene specific to C. lentillifera was discovered, which may represent a recent gene fragmentation event in the chloroplast genome. With the newly annotated exon-intron boundary information, gene structural annotation was greatly improved across the siphonous green algae lineages. Our data also revealed a type of non-canonical Group II introns, with a deviant secondary structure and intronic ORFs lacking known splicing or mobility domains. These widespread introns have conserved positions in their genes and are excised precisely despite lacking clear consensus intron boundaries. CONCLUSION: Our study fills important knowledge gaps in chloroplast genome organization and transcription in green algae, and provides new insights into expression of polycistronic transcripts, freestanding ORFs and fragmented genes in algal chloroplast genomes. Moreover, we revealed an unusual type of Group II intron with distinct features and conserved positions in Bryopsidales. Our data represents interesting additions to knowledge of chloroplast intron structure and highlights clusters of uncharacterized genes that probably play important roles in plastids.

Expression and Characterization of a Cold-Adapted Alginate Lyase with Exo/Endo-Type Activity from a Novel Marine Bacterium Alteromonas portus HB161718T.

The alginate lyases have unique advantages in the preparation of alginate oligosaccharides and processing of brown algae. Herein, a gene alg2951 encoding a PL7 family alginate lyase with exo/endo-type activity was cloned from a novel marine bacterium Alteromonas portus HB161718T and then expressed in Escherichia coli. The recombinant Alg2951 in the culture supernatant reached the activity of 63.6 U/mL, with a molecular weight of approximate 60 kDa. Alg2951 exhibited the maximum activity at 25 °C and pH 8.0, was relatively stable at temperatures lower than 30 °C, and showed a special preference to poly-guluronic acid (polyG) as well. Both NaCl and KCl had the most promotion effect on the enzyme activity of Alg2951 at 0.2 M, increasing by 21.6 and 19.1 times, respectively. The TCL (Thin Layer Chromatography) and ESI-MS (Electrospray Ionization Mass Spectrometry) analyses suggested that Alg2951 could catalyze the hydrolysis of sodium alginate to produce monosaccharides and trisaccharides. Furthermore, the enzymatic hydrolysates displayed good antioxidant activity by assays of the scavenging abilities towards radicals (hydroxyl and ABTS+) and the reducing power. Due to its cold-adapted and dual exo/endo-type properties, Alg2951 can be a potential enzymatic tool for industrial production.

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.

Androgen receptor suppresses vasculogenic mimicry in hepatocellular carcinoma via circRNA7/miRNA7-5p/VE-cadherin/Notch4 signalling.

Androgen receptor (AR) can suppress hepatocellular carcinoma (HCC) invasion and metastasis at an advanced stage. Vasculogenic mimicry (VM), a new vascularization pattern by which tumour tissues nourish themselves, is correlated with tumour progression and metastasis. Here, we investigated the effect of AR on the formation of VM and its mechanism in HCC. The results suggested that AR could down-regulate circular RNA (circRNA) 7, up-regulate micro RNA (miRNA) 7-5p, and suppress the formation of VM in HCC Small hairpin circR7 (ShcircR7) could reverse the impact on VM and expression of VE-cadherin and Notch4 increased by small interfering AR (shAR) in HCC, while inhibition of miR-7-5p blocked the formation of VM and expression of VE-cadherin and Notch4 decreased by AR overexpression (oeAR) in HCC. Mechanism dissection demonstrated that AR could directly target the circR7 host gene promoter to suppress circR7, and miR-7-5p might directly target the VE-cadherin and Notch4 3'UTR to suppress their expression in HCC. In addition, knockdown of Notch4 and/or VE-cadherin revealed that shVE-cadherin or shNotch4 alone could partially reverse the formation of HCC VM, while shVE-cadherin and shNotch4 together could completely suppress the formation of HCC VM. Those results indicate that AR could suppress the formation of HCC VM by down-regulating circRNA7/miRNA7-5p/VE-Cadherin/Notch4 signals in HCC, which will help in the design of novel therapies against HCC.

Paenibacillus algicola sp. nov., a novel alginate lyase-producing marine bacterium.

A Gram-stain-variable, facultatively anaerobic, endospore-forming, rod-shaped bacterium, designated HB172198T, was isolated from brown alga collected at Qishui Bay, Hainan, PR China. Phylogenetic analysis of 16S rRNA gene sequences indicated that strain HB172198T belonged to the genus Paenibacillus, and the closest phylogenetically related species was Paenibacillus lemnae NBRC 109972T (97.6% similarity). The other 16S rRNA gene sequence similarities were under 97.0%. The whole genome average nucleotide identity value between strain HB172198T and the closest type strain was 75.3% and the in silico DNA-DNA hybridization value was 20.2%. The predominant isoprenoid quinone was menaquinone 7 and the major fatty acids were anteiso-C15:0, C16:0, anteiso-C17:0, iso C16:0 and C16:1 ω11c. The combined phylogenetic relatedness, phenotypic and genotypic features supported the conclusion that strain HB172198T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus algicola sp. nov. is proposed. The type strain is HB172198T (=CGMCC 1.13583T=JCM 32683T).

Microbulbifer harenosus sp. nov., an alginate-degrading bacterium isolated from coastal sand.

A Gram-stain-negative, aerobic, rod-shaped bacterium with peritrichous flagella, designated strain HB161719T, was isolated from coastal sand collected from Tanmen Port in Hainan, PR China. The isolate was found to grow with 2-11 % (w/v) NaCl, at 15-45 °C and pH 6.0-10.0, with an optima of 2-3 % NaCl, 37 °C and pH 7.0, respectively. Chemotaxonomic analysis showed that Q-8 was detected as the sole respiratory quinone and that iso-C15 : 0 and summed features 3, 8 and 9 were the major cellular fatty acids. The G+C content of the genomic DNA was 58.2 mol%. Analysis of the 16S rRNA gene sequence of the strain showed an affiliation with the genus Microbulbifer, sharing 98.7, 98.4, 97.8 and 97.8 % sequence similarities to the closest relatives of Microbulbifer okinawensis ABABA23T, Microbulbifer pacificus SPO729T, Microbulbifer taiwanensis CC-LN1-12T and Microbulbifer gwangyangensis GY2T, respectively. Low DNA-DNA hybridization values showed that it formed a distinct genomic species. The combined phenotypic and molecular features supported that strain HB161719T represents a novel species of the genus Microbulbifer, for which the name Microbulbifer harenosus sp. nov. is proposed. The type strain is HB161719T (=CGMCC 1.13584T=JCM 32688T).

Bacillus caeni sp. nov., isolated from mangrove sediment.

A Gram-variable, aerobic, motile and irregular rod-shaped bacterium, designated HB172195T, was isolated from a mangrove sediment sample collected from Bamen Bay mangrove forest, China. Cells of the strain were oxidase-negative but positive for catalase and nitrate reduction. Strain HB172195T was found to grow at 15-50 °C (optimum, 25-40 °C), pH 5.0-9.0 (optimum, pH 7.0) and in 1.0-11.0 % (w/v) NaCl (optimum, 3-6 %). Chemotaxonomic analysis indicated that the sole respiratory quinone was MK-7 and the cell-wall peptidoglycan was meso-diaminopimelic acid. The predominant cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and C16 : 1ω7c alcohol. The major polar lipids consisted of phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol and an unidentified phospholipid. The genomic DNA G+C content was 40.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain was closely related to Bacillus hwajinpoensis SW-72T (96.3%), Bacillus algicola KMM 3737T (96.2 %) and Bacillus haemicentroti JSM 076093T (95.5 %). Based on polyphasic taxonomic characterization, strain HB172195T is considered to represent a novel species, for which the name Bacillus caeni sp. nov. is proposed. The type strain is HB172195T (=CGMCC 1.16730T=JCM 33411T).

Alteromonas portus sp. nov., an alginate lyase-excreting marine bacterium.

An alginate lyase-excreting bacterium, designated strain HB161718T, was isolated from coastal sand collected from Tanmen Port in Hainan, PR China. Cells were Gram-stain-negative rods and motile with a single polar flagellum. Its major isoprenoid quinone was ubiquinone 8 (Q-8), and its cellular fatty acid profile mainly consisted of C16 : 1 ω7c and/or C16 : 1 ω6c, C18 : 1 ω6c and/or C18 : 1 ω7c, C16 : 0, C17 : 0 10-methyl and C16 : 0 N alcohol. The G+C content of the genomic DNA was 44.1 mol%. 16S rRNA gene sequence analysis suggested that strain HB161718T belonged to the genus Alteromonas, sharing 99.5, 99.4, 99.2, 98.9 and 98.5 % sequence similarities to its closest relatives, Alteromonas macleodii JCM 20772T, Alteromonas gracilis 9a2T, Alteromonas australica H17T, Alteromonas marina SW-47T and Alteromonas mediterranea DET, respectively. The low values of DNA-DNA hybridization and average nucleotide identity showed that it formed a distinct genomic species. The combined phenotypic and molecular features supported the conclusion that strain HB161718T represents a novel species of the genus Alteromonas, for which the name Alteromonas portus sp. nov. is proposed. The type strain is HB161718T (=CGMCC 1.13585T=JCM 32687T).

Microbial community structure of soils in Bamenwan mangrove wetland.

Microbial community diversity and composition are important for the maintenance of mangrove ecosystem. Bacterial and archaeal community composition of the Bamenwan Mangrove Wetland soil in Hainan, China, was determined using pyrosequencing technique. Bacterial community composition presented differences among the five soil samples. Rhizobiales with higher abundance were observed in inner mangrove forest samples, while Desulfobacterales were in the seaward edge samples, and Frankiales, Gaiellales and Rhodospirillales in the landedge sample. For archaea, Crenarchaeota and Euryarchaeota dominated in five samples, but the proportion in each samples were different. Dominant archaeal community composition at the order level was similar in the seaward edge samples. The dominant archaeal clusters in the two inner mangrove forest samples were different, with Soil Crenarchaeotic Group (SCG) and Halobacteriales in sample inside of Bruguiera sexangula forest and SCG, Methanosarcinales and Marine Benthic Group B (MBGB) in sample inside of Xylocarpus mekongensis forest. The dominant archaeal clusters in land sample were unique, with Terrestrial Group and South African Gold Mine Group 1. The metabolic pathways including metabolism, genetic information processing, environmental information processing, cellular processes, organismal systems and human diseases were all detected for bacterial and archaeal functional profiles, but metabolic potentials among five samples were different.

Nonomuraea mangrovi sp. nov., an actinomycete isolated from mangrove soil.

A novel aerobic actinomycete, designated HA15826T, was isolated from a mangrove soil sample collected in Sanya, China. Scanning electron microscopy revealed that the isolate produced straight to slightly flexural spore chains with rough cylindrical spores. Chemotaxonomic tests showed that the cell wall contained meso-diaminopimelic acid and the major fatty acids were iso-C16 : 0, 10-methyl-C17 : 0, C17 : 1ω8c and C16 : 0. 16S rRNA gene sequence similarity analysis showed that strain HA15826T belonged to the genus Nonomuraea, being most closely related to Nonomuraea dietziae DSM 44320T (98.7 %), Nonomuraea candida HMC10T (98.4 %), Nonomuraea africana IFO 14745T (98.4 %), Nonomuraea roseola IFO 14685T (98.2 %) and Nonomuraea recticatena IFO 14525T (98.1 %). The DNA G+C content of the type strain is 73.2 %. DNA-DNA relatedness and comparative analyses of physiological, biochemical and chemotaxonomic data allowed genotypic and phenotypic differentiation of strain HA15826T from the closely related species. Thus, strain HA15826T should be classified as a novel species of the genus Nonomuraea, for which the name Nonomuraeamangrovi sp. nov. is proposed. The type strain is HA15826T (=CGMCC 4.7425T=DSM 105694T).

Streptomyces caeni sp. nov., isolated from mangrove mud.

A novel aerobic actinomycete, designated as HA15955T, was isolated from a mangrove mud sample collected in Sanya, China. Scanning electron microscopy revealed that HA15955T produced straight to spiral spore chains with smooth cylindrical spores. 16S rRNA gene sequence similarity showed that strain HA15955T belonged to the genus Streptomyces, was most closely related to Streptomyces speibonae NRRL B-24240T (98.7 % similarity) and formed a distinct subclade. The low relatedness value of DNA-DNA hybridization showed that it formed a distinct genomic species. Based on phenotypic, genotypic and phylogenetic data, strain HA15955T should be classified as a novel species of the genus Streptomyces, for which the name Streptomycescaeni sp. nov. is proposed. The type strain is HA15955T (=CGMCC 4.7426T=DSM 105693T).

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.

Diversity of Bacillus-like bacterial community in the sediments of the Bamenwan mangrove wetland in Hainan, China.

Members of the genus Bacillus and related spore-forming genera are ubiquitous. However, Bacillus-like species isolated from marine sediments have attracted less interest than their terrestrial relatives. Here, we investigated the diversity of Bacillus-like bacterial communities in the sediments of the Bamenwan mangrove wetland in Hainan, China, using culture-dependent and culture-independent methods, and present the first report on this subject. We also discovered some potential novel species from the sediment samples. Four families, Bacillaceae (58%), Paenibacillaceae (22%), Alicyclobacillaceae (15%), and Planococcaceae (5%), and 9 genera, Bacillus (42%), Paenibacillus (16%), Halobacillus (13%), Alicyclobacillus (11%), Rummeliibacillus (5%), Cohnella (5%), Tumebacillus (4%), Pontibacillus (3%), and Aneurinibacillus (2%), were identified by pyrosequencing. In contrast, only 4 genera, Bacillus (57%), Paenibacillus (23%), Halobacillus (14%), and Virgibacillus (6%), were detected by the culture-dependent method. In the 16S rDNA sequencing analysis, the isolates HB12036 and HB12037 were closest to Bacillus okuhidensis Kh10-101T and Paenibacillus xylanilyticus XIL14T with similarities of 94.8% and 95.9%, respectively, indicating that these were novel species. Bacillus sp. HB12035 and HB12040 exhibited antimicrobial activity against Staphylococcus aureus ATCC 25923, and Bacillus sp. HB12033 exhibited antimicrobial activity against Ustilago scitaminea Syd.

Paenibacillus silvae sp. nov., isolated from a tropical rainforest soil.

Two Gram-stain-positive, facultatively aerobic, endospore-forming and rod-shaped bacteria, designated DB13031T and DB13311, were isolated from the soil of the Jiaxi Nature Reserve in Hainan, PR China. 16S rRNA gene analysis of strains DB13031T and DB13311 showed that they fell within the Paenibacillus cluster, with highest similarities to Paenibacillus cucumis AP-115T (98.4 and 98.3 %, respectively), Paenibacillus barcinonensis BP-23T (98.3 and 98.2 %, respectively) and Paenibacillus oceanisediminis L10T (97.7 and 97.7 %, respectively). The DNA-DNA hybridization values between strain DB13031T and the type strains of its closest related species were 48.2, 38.1 and 43.5 %. Strain DB13031T contained menaquinone-7 (MK-7) as the predominant isoprenoid quinone and anteiso-C15 : 0, iso-C16 : 0 and C16 : 0 as the major cellular fatty acids. The cell-wall peptidoglycan was of the A1γ type and the major polar lipid profiles were diphosphatidylglycerol, phosphatidylethanolamine, four unknown aminophospholipids and four unknown phospholipids. Based on the phenotypic and genotypic data, it is proposed that the two isolates represent a novel species of the genus Paenibacillus, for which the name Paenibacillus silvae sp. nov. is proposed. The type strain is DB13031T (=CGMCC 1.12770T=DSM 28013T).