[Astragali Radix-Curcumae Rhizoma inhibits colon cancer progression and enhances 5-FU efficacy by regulating hypoxia-inducible factors and tumor stem cells].

The animal and cell models were used in this study to investigate the mechanism of Astragali Radix-Curcumae Rhizoma(HQEZ) in inhibiting colon cancer progression and enhancing the efficacy of 5-fluorouracil(5-FU) by regulating hypoxia-inducible factors and tumor stem cells. The animal model was established by subcutaneous transplantation of colon cancer HCT116 cells in nude mice, and 24 successfully modeled mice were randomized into model, 5-FU, HQEZ, and 5-FU+HQEZ groups. The tumor volume was measured every two days. Western blot was employed to measure the protein levels of epidermal growth factor receptor(EGFR), dihydropyrimidine dehydrogenase(DPYD), and thymidylate synthase(TYMS), the key targets of the hypoxic core region, as well as the hypoxia-inducible factors HIF-1α and HIF-2α and the cancer stem cell surface marker CD133 and SRY-box transcription factor 2(SOX2). The results of animal experiments showed that HQEZ slowed down the tumor growth and significantly increased the tumor inhibition rate of 5-FU. Compared with the model group, HQEZ significantly down-regulated the protein levels of EGFR and DPYD, and 5-FU+HQEZ significantly down-regulated the protein levels of EGFR and TYMS in tumors. Compared with the model group, HQEZ significantly down-regulated the protein levels of HIF-1α, HIF-2α, SOX2, and CD133 in the hypoxic core region. Compared with the 5-FU group, 5-FU+HQEZ lowered the protein levels of HIF-1α, HIF-2α, and SOX2. The cell experiments showed that the protein le-vels of HIF-1α and HIF-2α in HCT116 cells elevated significantly after low oxygen treatment. Compared with 5-FU(1.38 µmol·L~(-1)) alone, HQEZ(40 mg·mL~(-1)) and 5-FU+HQEZ significantly down-regulated the protein levels of HIF-1α, HIF-2α, and TYMS. In conclusion, HQEZ can inhibit the expression of hypoxia-responsive molecules in colon cancer cells and reduce the properties of cancer stem cells, thereby enhancing the therapeutic effect of 5-FU on colon cancer.

Case report: Emerging BRCA mutation confers benefit from olaparib after chemotherapy intolerance in advanced triple-negative breast cancer.

Key Clinical Message: In a patient with metastatic breast cancer, an acquired BRCA mutation in the BRCA gene was detected, resulting in benefits from olaparib treatment. This underscores the importance of ongoing genetic phenotype testing after paclitaxel chemotherapy. Abstract: Triple-negative breast cancer (TNBC) is associated with a poor prognosis and elevated mortality risk. BRCA mutations are commonly regarded as prevalent mutations in TNBC patients, strongly associated with congenital familial heredity. Dynamic changes in mutation sites, however, are rarely reported. In this case report, we report a 59-year-old TNBC patient who developed pulmonary metastases post-chemoradiotherapy. No BRCA mutations were detected through NGS. After 7.6 months of nab-paclitaxel treatment, the patient experienced progression of lung metastases, and BRCA mutations were detected through NGS testing. Subsequent administration of olaparib resulted in a reduction in lung metastasis, demonstrating significant therapeutic efficacy. This case underscores the infrequent occurrence of treatment-induced BRCA mutations and emphasizes the significance of dynamic NGS genetic testing for real-time assessment of a patient's mutational status.

Mesonia profundi sp. nov., isolated from deep-sea sediment of the Mariana Trench.

A Gram-stain-negative, aerobic, rod-shaped, non-flagellated, non-gliding bacterial strain, designated MT50T, was isolated from a deep-sea sediment sample collected from the Mariana Trench. Optimal growth of strain MT50T was observed at 25 °C, pH 7.0-7.5 and in the presence of 3-5 % (w/v) NaCl. The strain was positive for oxidase and catalase. Phylogenetic analysis of 16S rRNA gene sequences revealed that strain MT50T is affiliated with the genus Mesonia, showing the highest sequence similarity (98.5 %) to the type strain of Mesonia ostreae. The digital DNA-DNA hybridization and average nucleotide identity values between strain MT50T and four closely related type strains of known Mesonia species (14.1-54.8 % and 72.7-86.8 %, respectively) were all below the threshold values to discriminate bacterial species, indicating that strain MT50T is affiliated with a novel species within the genus. The genomic G+C content deduced from the genome of strain MT50T was 36.2 mol%. The major fatty acids of strain MT50T were iso-C15 : 0, iso-C17 : 0 3-OH and anteiso-C15 : 0. The predominant respiratory quinone of the strain was MK-6. The polar lipids of strain MT50T included phosphatidylethanolamine and two unidentified lipids. Based on the polyphasic data presented in this study, strain MT50T represents a novel species of the genus Mesonia, for which the name Mesonia profundi sp. nov. is proposed. The type strain is MT50T (=MCCC 1K07833T=KCTC 92380T).

[Mechanism of Astragali Radix-Curcumae Rhizoma in treating gastric cancer based on network pharmacology and experimental verification].

This study aims to investigate the mechanism of Astragali Radix-Curcumae Rhizoma(HQEZ) in the treatment of gastric cancer based on network pharmacology. Further, the SGC7901 cell model of gastric cancer was employed to validate the efficacy and key targets of the herb pair. Firstly, the CCK-8 assay was employed to evaluate the direct effect of HQEZ on the proliferation of gastric cancer SGC7901 cells. Then, network pharmacology methods were employed to investigate the active ingredients, key targets, and key signaling pathways involved in the treatment of gastric cancer with HQEZ. The results showed that HQEZ contained 18 potential active ingredients, such as quercetin, naringenin, and curcumin. The results of gene ontology(GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment suggested that the main targets of HQEZ in treating gastric cancer were involved in the regulation of protein serine/threonine kinase activity, activation of mitogen-activated protein kinase(MAPK) activity, cysteine-type endopeptidase activity, and negative regulation of protein serine/threonine kinase activity. The hypoxia-inducible factor-1(HIF-1) signaling pathway, ATP-binding cassette(ABC) transporters, cytochrome P450-mediated metabolism of xenobiotics, p53 signaling pathway, and cell apoptosis were key signaling pathways of HQEZ in treating gastric cancer. The cell experiments demonstrated that HQEZ significantly downregulated the expression of ATP-binding cassette subfamily B member 1(ABCB1), epidermal growth factor receptor(EGFR), phosphorylated serine/threonine kinase(p-AKT), hypoxia inducible factor 1 subunit alpha(HIF1A), B-cell lymphoma 2(BCL2), breast cancer susceptibility protein 1(BRCA1), DNA polymerase theta(POLH), ribonucleotide reductase M1(RRM1), and excision repair cross-complementation group 1(ERCC1), and upregulated the expression of tumor protein P53(TP53) and cysteinyl aspartate-specific proteinase(CAPS3). Finally, a multivariate COX regression model was adopted to study the relationship between gene expression and clinical information data of gastric cancer patients in the TCGA database, which demonstrated that the key targets of HQEZ were associated with the poor prognosis in gastric cancer patients. Further feature selection using the LASSO algorithm showed that EGFR, HIF1A, TP53, POLH, RRM1, and ERCC1 were closely associated with the survival of gastric can-cer patients. In conclusion, HQEZ regulates the expression of genes involved in DNA repair, survival, and apoptosis in gastric cancer cells via multiple targets and pathways, assisting the treatment of gastric cancer.

Multi-integrated approach for unraveling small open reading frames potentially associated with secondary metabolism in Streptomyces.

IMPORTANCE: Due to their small size and special chemical features, small open reading frame (smORF)-encoding peptides (SEPs) are often neglected. However, they may play critical roles in regulating gene expression, enzyme activity, and metabolite production. Studies on bacterial microproteins have mainly focused on pathogenic bacteria, which are importance to systematically investigate SEPs in streptomycetes and are rich sources of bioactive secondary metabolites. Our study is the first to perform a global identification of smORFs in streptomycetes. We established a peptidogenomic workflow for non-model microbial strains and identified multiple novel smORFs that are potentially linked to secondary metabolism in streptomycetes. Our multi-integrated approach in this study is meaningful to improve the quality and quantity of the detected smORFs. Ultimately, the workflow we established could be extended to other organisms and would benefit the genome mining of microproteins with critical functions for regulation and engineering useful microorganisms.

Spartinivicinus marinus sp. nov., isolated from intertidal sediment.

A Gram-stain-negative, aerobic, flagellated, and long rod-shaped bacterium, designated strain SM1973T, was isolated from an intertidal sediment sample collected from the coast of Qingdao, PR China. Strain SM1973T grew at 15-37 °C and with 0-5.5 % NaCl. It reduced nitrate to nitrite and hydrolysed aesculin but did not hydrolyse casein and gelatin. The strain showed the highest 16S rRNA gene sequence similarity (98.2 %) to the type strain of Spartinivicinus ruber. The phylogenetic trees based on the 16S rRNA genes and single-copy orthologous clusters showed that strain SM1973T clustered with S. ruber, forming a separate lineage within the family Zooshikellaceae. The major cellular fatty acids were summed feature 3 (C16 : 1 ω7с and/or C16 : 1 ω6с) and C16 : 0. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The main respiratory quinone was ubiquinone-9. The genomic DNA G+C content of strain SM1973T was 40.4 mol%. Based on the polyphasic evidence presented in this paper, strain SM1973T is considered to represent a novel species within the genus Spartinivicinus, for which the name Spartinivicinus marinus sp. nov. is proposed. The type strain is SM1973T (=MCCC 1K04833T=KCTC 72846T).

Salinimicrobium profundisediminis sp. nov., isolated from deep-sea sediment of the Mariana Trench.

A Gram-stain-negative, aerobic, rod-shaped, non-gliding bacterial strain, designated as MT39T, was isolated from a deep-sea sediment sample collected from the Mariana Trench. Strain MT39T grew optimally at 35°C and pH 7.0, and could tolerate up to 10% (w/v) NaCl. The strain was positive for catalase and negative for oxidase. The genome of strain MT39T was 4 033 307 bp, with a 41.1 mol % genomic G+C content and 3514 coding sequences. Phylogenetic analysis based on 16S rRNA gene sequences placed strain MT39T within the genus Salinimicrobium, showing the highest 16S rRNA gene sequence similarity to Salinimicrobium terrea CGMCC 1.6308T (98.1%). The average nucleotide identity and in silico DNA-DNA hybridization values between strain MT39T and the type strains of seven Salinimicrobium species were all less than the threshold values to discriminate bacterial species, indicating that strain MT39T is affiliated with a novel species within the genus. The major cellular fatty acids of strain MT39T were iso-C15 : 0, anteiso-C15 : 0 and iso-C17 : 0 3-OH. Polar lipids of strain MT39T included phosphatidylethanolamine, one unidentified aminolipid and four unidentified lipids. Menaquinone-6 was the only respiratory quinone in strain MT39T. On the basis of the polyphasic data present in this study, strain MT39T represents a novel species of the genus Salinimicrobium, for which the name Salinimicrobium profundisediminis sp. nov. is proposed, with type strain being MT39T (=MCCC 1K07832T=KCTC 92381T).

Closed or Unclosed Mesentery? A Meta-analysis of Internal Herniation After Laparoscopic Roux-en-Y Gastric Bypass.

During the laparoscopic Roux-en-Y gastric bypass procedure, closing mesentery or not was still controversial according to preexisted studies. So, the current meta-analysis aimed to compare the outcome of closure versus non-closure of mesenteric defects in laparoscopic Roux-en-Y gastric bypass. Fifteen studies were included, enrolling 53,488 patients. Based on the outcome of analysis, regarding internal hernia, Petersen space's IH, jejunal mesenteric's IH, hospital days, and reoperation, closure of the mesentery was better than non-closure. Besides, small bowel obstruction, anastomosis ulcer, stenosis, leakage, bleeding, gastrointestinal perforation, and postoperative BMI of patients show no difference between non-closure and closure.

Inhibition of MRTF activation as a clinically achievable anti-fibrotic mechanism for pirfenidone.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic disease characterised by aberrant fibroblast/myofibroblast accumulation and excessive collagen matrix deposition in the alveolar areas of lungs. As the first approved IPF medication, pirfenidone (PFD) significantly decelerates lung function decline while its underlying anti-fibrotic mechanism remains elusive. METHODS: We performed transcriptomic and immunofluorescence analyses of primary human IPF tissues. RESULTS: We showed that myocardin-related transcription factor (MRTF) signalling is activated in myofibroblasts accumulated in IPF lungs. Furthermore, we showed that PFD inhibits MRTF activation in primary human lung fibroblasts at clinically achievable concentrations (half-maximal inhibitory concentration 50-150 µM, maximal inhibition >90%, maximal concentration of PFD in patients <100 µM). Mechanistically, PFD appears to exert its inhibitory effects by promoting the interaction between MRTF and actin indirectly. Finally, PFD-treated IPF lungs exhibit significantly less MRTF activation in fibroblast foci areas than naïve IPF lungs. CONCLUSIONS: Our results suggest MRTF signalling as a direct target for PFD and implicate that some of the anti-fibrotic effects of PFD may be due to MRTF inhibition in lung fibroblasts.

Gilvimarinus xylanilyticus sp. nov., a novel 1,3-xylanase-secreting bacterium isolated from a marine green alga.

1,3-xylan, an important organic carbon in the ocean, is peculiar to marine algae. 1,3-xylanase-secreting bacteria and their extracellular 1,3-xylanases play pivotal roles in the degradation and biomass conversion of 1,3-xylan. However, only a few 1,3-xylanase-secreting bacteria and 1,3-xylanases have been reported. Here, we identified a novel marine bacterium capable of secreting 1,3-xylanases, designated as strain HB14T. Phylogenetic analysis revealed that strain HB14T clustered tightly with known species of the genus Gilvimarinus, showing the highest 16S rRNA gene sequence similarity (97.7%) with the type strain of Gilvimarinus chinensis. Based on phylogenetic, genomic, chemotaxonomic and phenotypic studies, strain HB14T was classified as a representative of a novel species in the genus Gilvimarinus, for which the name Gilvimarinus xylanilyticus sp. nov. was proposed. The type strain is HB14T (=CCTCC AB 2022109T = KCTC 92379T). Four 1,3-xylanases secreted by strain HB14T were identified based on genome and secretome analyses, and the two (Xyn65 and Xyn80) with relatively higher abundance in secretome were successfully expressed in Escherichia coli and biochemically characterized. They showed the highest activity at pH 6.0-7.0 and 40°C and released mainly 1,3-xylobiose and 1,3-xylotriose from 1,3-xylan. These data suggest that strain HB14T acts as a player in marine 1,3-xylan degradation and recycling and that its extracellular 1,3-xylanases may have a good potential in 1,3-xylooligosaccharides preparation.

Performance of the PRISM I, PIM2, PELOD-2 and PRISM IV scoring systems in western China: a multicenter prospective study.

BACKGROUND: The aim of this study was to evaluate the performance of the four scoring tools in predicting mortality in pediatric intensive care units (PICUs) in western China. METHODS: This was a multicenter, prospective, cohort study conducted in six PICUs in western China. The performances of the scoring systems were evaluated based on both discrimination and calibration. Discrimination was assessed by calculating the area under the receiver operating characteristic curve (AUC) for each model. Calibration was measured across defined groups based on mortality risk using the Hosmer-Lemeshow goodness-of-fit test. RESULTS: A total of 2034 patients were included in this study, of whom 127 (6.2%) died. For the entire cohort, AUCs for Pediatric Risk of Mortality Score (PRISM) I, Pediatric Index of Mortality 2 (PIM2), Pediatric Logistic Organ Dysfunction Score-2 (PELOD-2) and PRISM IV were 0.88 [95% confidence interval (CI) 0.85-0.92], 0.84 (95% CI 0.80-0.88), 0.80 (95% CI 0.75-0.85), and 0.91 (95% CI 0.88-0.94), respectively. The Hosmer-Lemeshow goodness-of-fit Chi-square value was 12.71 (P = 0.12) for PRISM I, 4.70 (P = 0.79) for PIM2, 205.98 (P < 0.001) for PELOD-2, and 7.50 (P = 0.48) for PRISM IV [degree of freedom (df) = 8]. The standardized mortality ratios obtained with the PRISM I, PIM2, PELOD-2, and PRISM IV models were 0.87 (95% CI, 0.75-1.01), 0.97 (95% CI, 0.85-1.12), 1.74 (95% CI, 1.58-1.92), and 1.05 (95% CI, 0.92-1.21), respectively. CONCLUSIONS: PRISM IV performed best and can be used as a prediction tool in PICUs in Western China. However, PRISM IV needs to be further validated in NICUs.

Cardiac Safety in Breast Cancer Patients Receiving Pegylated Liposome Doxorubicin Sequential Anti-HER2 Monoclonal Antibody Therapy.

Background: Cardiotoxicity associated with the sequential use of anthracyclines followed by trastuzumab is common in adjuvant therapy of patients with HER2-positive early breast cancer (eBC). However, the cardiac safety of trastuzumab concurrent with pegylated liposomal doxorubicin (PLD) is relatively less studied. Method: Clinical data of patients with HER2-positive eBC treated with PLD and cyclophosphamide (PLD-C) followed by taxanes plus trastuzumab ± pertuzumab (TH or TPH) who then completed standard anti-HER2 treatment for 12 months from June 2012 to August 2021 were retrospectively collected. The primary endpoints were clinical and subclinical cardiotoxicity. Result: In total, 70 eligible patients were enrolled. Among them, 55 patients (78.6%) received PLD-C → TH and 15 patients (21.4%) received PLD-C → TPH. The median follow-up time was 41.8 months. Until August 2021, only two patients had recurrent or metastatic diseases, with 2-year and 5-year disease-free survivals of 98.6% and 96.8%, respectively. Clinical cardiotoxicity occurred in six patients (8.6%), and all of them had an absolute decline of ≥16% from baseline left ventricular ejection fraction (LVEF) but not below the lower limit of normal (LLN = 50%). Subclinical cardiotoxicity events occurred in 17 patients (24.3%), and all of them had absolute declines of ≥10% and <16% from baseline LVEF but not below the LLN. No patients were interrupted from treatment, and all patients completed anti-HER2 treatment for 12 months. The sharpest decrease in LVEF was observed at 18 months after the start of PLD treatment. The cumulative incidences of clinical and subclinical cardiotoxicity were 9.8% and 28.3%, respectively. In the univariate analysis, body mass index, age, left chest wall radiotherapy, and ongoing cardiovascular risk factors were not significantly associated with clinical or subclinical cardiotoxicity (p > 0.05). No patients had congestive heart failure or death caused by PLD or anti-HER2 treatment. Conclusion: The sequential use of PLD and trastuzumab showed a lower incidence of clinical cardiotoxicity, presented as asymptomatic decreased LVEF, compared with the results obtained in previous clinical studies using conventional anthracycline, taxanes and trastuzumab. The study regimen demonstrated good cardiac tolerance and is an alternative strategy for cardioprotection in patients with HER2-positive eBC.

Chemoproteomics reveals berberine directly binds to PKM2 to inhibit the progression of colorectal cancer.

Colorectal cancer is one of the most serious tumors and berberine can inhibit the recurrence and transformation of colorectal adenoma into colorectal cancer. However, the direct binding target proteins of berberine in inhibiting colorectal cancer remain unclear. In this study, the chemical proteomics method was used and demonstrated that berberine is directly bound to pyruvate kinase isozyme type M2 (PKM2) in colorectal cancer cells. The triangular N-O-O triangular structure of berberine contributed to hydrophobic interaction with I119 amino acid residues and π-π interaction with F244 amino acid residues of PKM2 protein. Moreover, berberine was shown to inhibit the reprogramming of glucose metabolism and the phosphorylation of STAT3, down regulate the expression of Bcl-2 and Cyclin D1 genes, ultimately inhibiting the progression of colorectal cancer. This study uncovered the direct binding target protein and mechanism of berberine to improve metabolic reprogramming in colorectal cancer, which is helpful to guide the optimization of berberine.

Arsukibacterium indicum sp. nov., isolated from deep-sea sediment, and transfer of Rheinheimera tuosuensis and Rheinheimera perlucida to the genus Arsukibacterium as Arsukibacterium tuosuense comb. nov. and Arsukibacterium perlucidum comb. nov.

A Gram-stain-negative, aerobic, flagellated and rod-shaped bacterium, designated strain SM2107T, was isolated from a deep-sea sediment sample collected from the Southwest Indian Ocean. Strain SM2107T grew at 4-40 °C and with 0-10.0 % (w/v) NaCl. It reduced nitrate to nitrite and hydrolysed casein, gelatin, chitin and DNA. The phylogenetic trees based on the 16S rRNA genes and single-copy orthologous clusters showed that strain SM2107T, together with Rheinheimera tuosuensis, Rheinheimera perlucida and Arsukibacterium ikkense, formed a separate clade, having the highest similarity to the type strain of Rheinheimera tuosuensis (98.3%). The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol and the major cellular fatty acids were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C16 : 0, C17 : 1 ω8с and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c). The only respiratory quinone was Q-8. The genomic DNA G+C content of strain SM2107T was 48.8 %. The digital DNA-DNA hybridization values between strain SM2107T and type strains of Rheinheimera tuosuensis, Rheinheimera perlucida and Arsukibacterium ikkense were 41.16, 37.70 and 31.80 %, while the average amino acid identity values between them were 87.59, 86.76 and 83.64 %, respectively. Based on the polyphasic evidence presented in this study, strain SM2107T was considered to represent a novel species within the genus Arsukibacterium, for which the name Arsukibacterium indicum was proposed. The type strain is SM2107T (=MCCC M24986T=KCTC 82921T). Moreover, the transfer of Rheinheimera tuosuensis and Rheinheimera perlucida to the genus Arsukibacterium as Arsukibacterium tuosuense comb. nov. (type strain TS-T4T=CGMCC 1.12461T=JCM 19264T) and Arsukibacterium perlucidum comb. nov. (type strain BA131T=LMG 23581T=CIP 109200T) is also proposed.

Enhanced enantioseparation of drugs by capillary electrochromatography with a L-cysteine functionalized gold nanoparticle based stationary phase.

Nanoparticles, which have unique properties, have attracted growing attention in enantiomeric separation nowadays. In this paper, an L-cysteine functionalized gold nanoparticle (L-Cys-GNP) based capillary column was prepared and applied in separating drug enantiomers in capillary electrochromatography (CEC) with lactobionic acid (LA) as a chiral selector. Compared with bare fused-silica capillary columns, the capillary columns modified with L-Cys-GNPs showed excellent chiral separation performance. A series of parameters affecting the enantiomeric separation were systematically investigated.

A non-canonical cGAS-STING-PERK pathway facilitates the translational program critical for senescence and organ fibrosis.

Innate DNA sensing via the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) mechanism surveys microbial invasion and cellular damage and thus participates in various human infectious diseases, autoimmune diseases and cancers. However, how DNA sensing rapidly and adaptively shapes cellular physiology is incompletely known. Here we identify the STING-PKR-like endoplasmic reticulum kinase (PERK)-eIF2α pathway, a previously unknown cGAS-STING mechanism, enabling an innate immunity control of cap-dependent messenger RNA translation. Upon cGAMP binding, STING at the ER binds and directly activates the ER-located kinase PERK via their intracellular domains, which precedes TBK1-IRF3 activation and is irrelevant to the unfolded protein response. The activated PERK phosphorylates eIF2α, forming an inflammatory- and survival-preferred translation program. Notably, this STING-PERK-eIF2α pathway is evolutionarily primitive and physiologically critical to cellular senescence and organ fibrosis. Pharmacologically or genetically targeting this non-canonical cGAS-STING pathway attenuated lung and kidney fibrosis. Collectively, the findings identify an alternative innate immune pathway and its critical role in organ fibrosis, report an innate immunity-directed translation program and suggest the therapeutic potential for targeting the STING-PERK pathway in treating fibrotic diseases.

Alteromonas oceanisediminis sp. nov., isolated from deep-sea sediment.

A Gram-stain-negative, aerobic and rod-shaped bacterium, designated strain SM 2104T, was isolated from a deep-sea sediment sample collected from the Southwest Indian Ocean. Strain SM 2104T grew at 10-37 °C (optimum at 25 °C), and with 1.0-9.0% (w/v, optimum with 2-4%) NaCl. It hydrolyzed starch, tween 80 and gelatin but did not reduced nitrate to nitrite. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM 2104T was affiliated with the genus Alteromonas, sharing the highest 16S rRNA gene sequence similarities with type strains of Alteromonas flava (97.5%) and Alteromonas facilis (97.4%) and forming a distinct clade together with the two Alteromonas species. The digital DNA-DNA hybridization and average nucleotide identity values between strain SM 2104 T and type strains of Alteromonas flava and Alteromonas facilis were below 14.5%, and 71.0%, respectively. The major fatty acids of strain SM 2104T were summed feature 3 (C16:1ω6c/C16:1ω7c), C16:0 and summed feature 8 (C18:1ω7c/C18:1ω6c). The major polar lipids of strain SM 2104T were phosphatidylethanolamine and phosphatidylglycerol and the only respiratory quinone of strain SM 2104T was ubiquinone-8. The genomic DNA G + C content of strain SM 2104T was 48.0%. On the basis of the phylogenetic, phenotypic, chemotaxonomic and genomic analyses presented in this study, strain SM 2104T is considered to represent a novel species within the genus Alteromonas, for which the name Alteromonas oceansediminis sp. nov. is proposed. The type strain is SM 2104T (= CCTCC AB 2021121T = KCTC 82867T).

Mechanistic Insight into the Fragmentation of Type I Collagen Fibers into Peptides and Amino Acids by a Vibrio Collagenase.

Vibrio collagenases of the M9A subfamily are closely related to Vibrio pathogenesis for their role in collagen degradation during host invasion. Although some Vibrio collagenases have been characterized, the collagen degradation mechanism of Vibrio collagenase is still largely unknown. Here, an M9A collagenase, VP397, from marine Vibrio pomeroyi strain 12613 was characterized, and its fragmentation pattern on insoluble type I collagen fibers was studied. VP397 is a typical Vibrio collagenase composed of a catalytic module featuring a peptidase M9N domain and a peptidase M9 domain and two accessory bacterial prepeptidase C-terminal domains (PPC domains). It can hydrolyze various collagenous substrates, including fish collagen, mammalian collagens of types I to V, triple-helical peptide [(POG)10]3, gelatin, and 4-phenylazobenzyloxycarbonyl-Pro-Leu-Gly-Pro-o-Arg (Pz-peptide). Atomic force microscopy (AFM) observation and biochemical analyses revealed that VP397 first assaults the C-telopeptide region to dismantle the compact structure of collagen and dissociate tropocollagen fragments, which are further digested into peptides and amino acids by VP397 mainly at the Y-Gly bonds in the repeating Gly-X-Y triplets. In addition, domain deletion mutagenesis showed that the catalytic module of VP397 alone is capable of hydrolyzing type I collagen fibers and that its C-terminal PPC2 domain functions as a collagen-binding domain during collagenolysis. Based on our results, a model for the collagenolytic mechanism of VP397 is proposed. This study sheds light on the mechanism of collagen degradation by Vibrio collagenase, offering a better understanding of the pathogenesis of Vibrio and helping in developing the potential applications of Vibrio collagenase in industrial and medical areas. IMPORTANCE Many Vibrio species are pathogens and cause serious diseases in humans and aquatic animals. The collagenases produced by pathogenic Vibrio species have been regarded as important virulence factors, which occasionally exhibit direct pathogenicity to the infected host or facilitate other toxins' diffusion through the digestion of host collagen. However, our knowledge concerning the collagen degradation mechanism of Vibrio collagenase is still limited. This study reveals the degradation strategy of Vibrio collagenase VP397 on type I collagen. VP397 binds on collagen fibrils via its C-terminal PPC2 domain, and its catalytic module first assaults the C-telopeptide region and then attacks the Y-Gly bonds in the dissociated tropocollagen fragments to release peptides and amino acids. This study offers new knowledge regarding the collagenolytic mechanism of Vibrio collagenase, which is helpful for better understanding the role of collagenase in Vibrio pathogenesis and for developing its industrial and medical applications.

Celeribacter litoreus sp. nov., isolated from intertidal sediment.

A Gram-negative, aerobic, non-flagellated and rod-shaped bacterium, strain ASW11-22T, was isolated from an intertidal sediment collected from a coastal area of Qingdao, PR China. The strain grew at 15-40 °C (optimum, 37 °C), at pH 6.0-9.0 (optimum, pH 7.0) and with 0.5-10 % (w/v) NaCl (optimum, 1.0 %). It hydrolysed gelatin and aesculin but did not reduce nitrate to nitrite. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain ASW11-22T belonged to the genus Celeribacter, showing the highest sequence similarity to the type strains of Celeribacter halophilus MCCC 1A06432T (98.20 %) and Celeribacter ethanolicus NH195T (97.84 %). The genomic DNA G+C content was 59.1 mol%. The major cellular fatty acid (>10 %) of the strain was summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and its main polar lipids were phosphatidylglycerol and one unidentified aminolipid. The sole respiratory quinone of strain ASW11-22T was ubiquinone-10. On the basis of the polyphasic evidence presented in this paper, strain ASW11-22T represents a novel Celeribacter species, for which the name Celeribacter litoreus sp. nov. is proposed. The type strain is ASW11-22T (=KCTC 82495T=MCCC 1K05584T).