Integrin-Linked Kinase in the Development of Gastric Tumors Induced by Helicobacter pylori: Regulation and Prevention Potential.

BACKGROUND: Integrin-linked kinase (ILK) is crucial in solid tumors by regulating the Hippo-Yes-associated protein 1 (YAP) pathway. This study aimed to uncover how Helicobacter pylori influences ILK levels and its role in regulating YAP during H. pylori-induced gastric cancer. MATERIALS AND METHODS: GES-1 cells with stable Ilk knockdown and overexpression and a mouse carcinogenesis model for H. pylori infection were constructed. And ILK, the phosphorylated mammalian STE20-like protein kinase 1 (MST1), large tumor suppressor 1 (LATS1; S909, T1079), and YAP (S109, S127) were detected in cells, and mice by western blotting, as well as fluorescence intensity of YAP were assayed by immunofluorescence. YAP downstream genes Igfbp4 and Ctgf, the pathological changes and tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), interleukin-1beta (IL-1ß), and nitric oxide (NO) levels in mice gastric tissues were detected by real-time PCR, H&E, and ELISA assays. RESULTS: In this study, stable Ilk knockdown cells exhibited significantly higher phosphorylated levels of MST1, LATS1, and YAP, as well as increased YAP in the nuclei of GES-1 cells. Conversely, cells with Ilk overexpression showed opposite results. H. pylori infection led to decreased ILK levels in gastric epithelial cells but increased ILK levels in gastric cancer cell lines (MGC803, SGC7901) and gastric cancer tissues in mice. Treatment with the ILK inhibitor OST-T315 elevated the phosphorylated MST, LATS1, and YAP levels, and inhibited the mRNA levels of Igfbp4 and Ctgf at 44, 48 week-aged mice. OST-T315 also reduced the release of TNF-α, IL-6, IL-1ß, and NO, as well as the progression of gastric cancer caused by H. pylori and N-Nitroso-N-methylurea (NMU) treatment. CONCLUSION: Upon initiation of gastric tumorigenesis signals, H. pylori increases ILK levels and suppresses Hippo signaling, thereby promoting YAP activation and gastric cancer progression. ILK can serve as a potential prevention target to impede H. pylori-induced gastric cancer.

Antagonizing roles of SHP1 in the pathogenesis of Helicobacter pylori infection.

BACKGROUND: SHP1 has been documented as a tumor suppressor and it was thought to play an antagonistic role in the pathogenesis of Helicobacter pylori infection. In this study, the exact mechanism of this antagonistic action was studied. MATERIALS AND METHODS: AGS, MGC803, and GES-1 cells were infected with H. pylori, intracellular distribution changes of SHP1 were first detected by immunofluorescence. SHP1 overexpression and knockdown were then constructed in these cells to investigate its antagonistic roles in H. pylori infection. Migration and invasion of infected cells were detected by transwell assay, secretion of IL-8 was examined via ELISA, the cells with hummingbird-like alteration were determined by microexamination, and activation of JAK2/STAT3, PI3K/Akt, and ERK pathways were detected by immunoblotting. Mice infection model was established and gastric pathological changes were evaluated. Finally, the SHP1 activator sorafenib was used to analyze the attenuating effect of SHP1 activation on H. pylori pathogenesis in vitro and in vivo. RESULTS: The sub-localization of SHP1 changed after H. pylori infection, specifically that the majority of the cytoplasmic SHP1 was transferred to the cell membrane. SHP1 inhibited H. pylori-induced activation of JAK2/STAT3 pathway, PI3K/Akt pathway, nuclear translocation of NF-κB, and then reduced EMT, migration, invasion, and IL-8 secretion. In addition, SHP1 inhibited the formation of CagA-SHP2 complex by dephosphorylating phosphorylated CagA, reduced ERK phosphorylation and the formation of CagA-dependent hummingbird-like cells. In the mice infection model, gastric pathological changes were observed and increased IL-8 secretion, indicators of cell proliferation and EMT progression were also detected. By activating SHP1 with sorafenib, a significant curative effect against H. pylori infection was obtained in vitro and in vivo. CONCLUSIONS: SHP1 plays an antagonistic role in H. pylori pathogenesis by inhibiting JAK2/STAT3 and PI3K/Akt pathways, NF-κB nuclear translocation, and CagA phosphorylation, thereby reducing cell EMT, migration, invasion, IL-8 secretion, and hummingbird-like changes.

Chronic exposure to polystyrene nanoplastics induces intestinal mechanical and immune barrier dysfunction in mice.

Micro(nano)plastics are prevalent in the environment, and prolonged exposure to them represents a threat to human health. The goal of this study is to assess the health risk of long-term exposure to nanoplastics (NPs) at environmental concentrations on the intestinal mechanical and immune barrier in mice. In this study, mice were provided drinking water containing polystyrene NPs (PS-NPs; 0.1, 1, and 10 mg·L-1) for 32 consecutive weeks. The levels of endocytosis proteins caveolin and clathrin and of tight junctional proteins claudin-1, occludin, and ZO-1, and morphological changes, proportion of lymphocytes B in MLNs and lymphocytes T in IELs and LPLs were determined by immunohistochemistry, hematoxylin-eosin, and flow cytometry assays in the intestinal tissues of mice at 28 weeks. The activities or concentrations of ROS, SOD, MDA, and GSH-Px and inflammatory factors (IL-1ß, IL-6, and TNF-α) in the intestinal tissues of mice were measured by ELISA at 12, 16, 20, 24, and 32 weeks. Compared with the control group, oral ingested PS-NPs entered the intestinal tissues of mice and upregulated expression levels of the clathrin and caveolin. The intestinal tissue structure of mice in the PS-NPs (1 and 10 mg·L-1) exposure groups showed significant abnormalities, such as villus erosion, decreased of crypts numbers and large infiltration of inflammatory cells. Exposure to 0.1 mg·L-1 PS-NPs decreased occludin protein levels, but not claudin-1 and ZO-1 levels. The levels of these three tight junction proteins decreased significantly in the 1 and 10 mg·L-1 PS-NPs exposed groups. Exposure to PS-NPs led to a significant time- and dose-dependent increase in ROS and MDA levels, and concurrently decreased GSH-Px and SOD contents. Exposure to PS-NPs increased the proportion of B cells in MLNs, and decreased the proportion of CD8+ T cells in IELs and LPLs. The levels of pro-inflammatory cytokines IL-6, TNF-α and IL-1ß were markedly elevated after PS-NPs exposure. Long-term PS-NPs exposure impaired intestinal mechanical and immune barrier, and indicate a potentially significant threat to human health.

Chloroquine inhibited Helicobacter pylori-related gastric carcinogenesis by YAP-ß-catenin-autophagy axis.

YAP participates in autophagy associated with many diseases. In this study, we demonstrate that YAP promotes autophagy by interacting with beclin 1, upregulating beclin 1 and LC3B-II protein expression, and promoting autophagosome formation after H. pylori infection in a vacuolating cytotoxin A-dependent manner. The protein levels of ß-catenin in the cytoplasm and nuclei of GES-1 cells and the mRNA levels of Axin2, Myc, Lgr5, and Ccnd1 were increased in H. pylori-infected cells or YAP-overexpressed cells, but were decreased in YAP-silenced cells. The ß-catenin inhibitor XAV939 significantly downregulated autophagy, whereas the activator LiCl showed opposite effects. An H. pylori-infected mouse model of gastric carcinoma was successfully established. The mouse model showed that H. pylori infection, when combined with NMU, promoted the tumorigenesis of gastric tissues; increased IL-1ß, IL-6, and TNF-α levels; promoted NO release; and increased the expression of beclin 1, LC3B-II more than NMU alone. Chloroquine inhibited these phenomena, but did not completely attenuate the effects of H. pylori. These results demonstrate that chloroquine can be used as a drug for the treatment of H. pylori-related gastric cancer, but the treatment should simultaneously remove H. pylori.

Helicobacter pylori infection induces autophagy via ILK regulation of NOXs-ROS-Nrf2/HO-1-ROS loop.

Reactive oxygen species (ROS) can regulate the occurrence of autophagy, and effective control of the balance between ROS and autophagy may be an important strategy for Helicobacter pylori induced gastric-related diseases. In this study, infection with H. pylori led to a lower level of ILK phosphorylation and increased ROS generation. Knockdown of ILK enhanced total ROS generation, and upregulated NADPH oxidase (NOX) subunit p22-phox levels. Inhibition of NOXs affected total ROS generation. The inhibition of NOX and ROS generation reduced Nrf2 and HO-1 levels, and knockdown of ILK significantly enhanced Nrf2 levels in H. pylori-infected GES-1 cells. Activation of Nrf2 by DMF decreased ROS levels. Therefore, NOX-dependent ROS production regulated by ILK was essential for activation of Nrf2/HO-1 signaling pathways in H. pylori-infected GES-1 cells. Beclin1, ATG5 and LC3B-II levels were higher both in H. pylori-infected and ILK-knockdown GES-1 cells. In NAC-pretreated GES-1 cells infected with H. pylori, the LC3B-II level was decreased compared to that in cells after H. pylori infection alone. Stable low expression of ILK with further knockdown of Beclin1 or ATG5 significantly reduced LC3B-II levels in GES-1 cells, while with the addition of the autophagy inhibitor chloroquine (CQ), LC3B-II and p62 protein levels were both remarkably upregulated. H. pylori accelerated the accumulation of ROS and further led to the induction of ROS-mediated autophagy by inhibiting ILK levels. Together, these results indicate that H. pylori infection manipulates the NOX-ROS-Nrf2/HO-1-ROS loop to control intracellular oxygen stress and further induced ROS-mediated autophagy by inhibiting ILK levels.

Oceanospirillum sediminis sp. nov., Isolated From Coastal Sediment in the Yellow Sea.

A novel Gram-negative, motile, aerobic, spiral-shaped bacterium designated D5T, was isolated from a coastal sediment collected in the Yellow Sea. Optimal growth occurred at 30 °C, pH 7.0-8.0 and in the presence of 1-3% (w/v) NaCl. Strain D5T contained ubiquinone 8 (Q-8) as the predominant respiratory quinone. The major fatty acids (> 10%) were C16:0, C16:1 ω7c/C16:1 ω6c and C18:1w7c/C18:1w6c. The main polar lipids were phosphatidylglycerol and phosphatidylethanolamine. The draft genome is 5.6 Mb in length, and DNA G + C content is 47.2 mol%. 16S rRNA gene sequences showed that strain D5T is most closely related to Oceanospirillum beijerinckii NBRC 15445T (97.8%, sequence similarity). However, the digital DNA-DNA hybridization (dDDH) value and average nucleotide identity (ANI) between strain D5T and O. beijerinckii is only 27.8% and 77.1%. Phylogenetic trees based on 16S rRNA gene sequences and whole genomes all indicated that strain D5T formed a separate branch in the genus Oceanospirillum. Combined results of the polyphasic analyses suggested that strain D5T represents a novel species in the genus Oceanospirillum, for which the name Oceanospirillum sediminis sp. nov. is proposed. The type strain is D5T (= MCCC 1K06061T = KCTC 62987T).

Helicobacter pylori regulates ILK to influence autophagy through Rac1 and RhoA signaling pathways in gastric epithelial cells.

The ability of Helicobacter pylori to manipulate host autophagy is an important pathogenic mechanism. We found an inverse correlation between the expression of ILK and the autophagy marker protein LC3B in H. pylori-positive human samples, H. pylori-infected mice models and H. pylori-infected GES-1 cell lines. When the ILK-knockdown GES-1 cells were infected by H. pylori, CagA were significantly degraded, autophagosomes accumulation and autolysosomes formation were significantly increased, and LC3B protein levels and ratio of LC3BII to LC3BI were also remarkably upregulated. And chloroquine treatment increased LC3B levels in ILK-knockdown GES-1 cells. The expression levels of both Rac1 and RhoA were downregulated in GES-1 cells after H. pylori infection and were decreased in ILK-knockdown GES-1 cells. The mRNA and protein levels of PAK1, MLC, and LIMK were significantly decreased and cofilin mRNA and protein levels were significantly increased in GES-1 cells treated with the Rac1 inhibitor NSC 23766. The mRNA and protein levels of ROCK1, ROCK2, MLC, and LIMK1 were significantly reduced and cofilin mRNA and protein levels were significantly increased in GES-1 cells treated with the RhoA inhibitor CCG-1423. F-actin was significantly reduced in Rac1- or RhoA-inhibited GES-1 cells. F-actin depolymerization induced autophagosomes accumulation, autolysosomes formation, and the increase of LC3B levels in GES-1 cells. Therefore, these findings revealed that ILK could serve as a novel regulator to affect Rac1/PAK1 and RhoA/ROCKs signaling pathways, thereby influencing H. pylori-induced autophagy.

Vibrio marinisediminis sp. nov., Isolated from Marine Sediment.

A novel Gram-stain-negative, facultative anaerobic, motile bacterium, designated as 404T, was isolated from a marine sediment sample in the Bohai Gulf, China. Growth was observed at 10-35 °C (optimum, 20-25 °C) and in the presence of 1.0-6.0% (w/v) NaCl (optimum, 1.0-3.0%). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain 404T belonged to the genus Vibrio, showing the highest sequence similarity to Vibrio renipiscarius KCTC 42287T (97.6%). The draft genome is 4.5 Mb in length, containing 4278 protein-coding genes, 60 tRNA genes and 9 rRNA genes, and DNA G+C content is 44.1 mol%. Strain 404T contains phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine, and phospholipid as the main polar lipids, and the predominant quinone is ubiquinone Q-8. The major cellular fatty acids (>8.0%) are C16 : 1ω6c and/or C16 : 1ω7c, C16 : 0, C18 : 1ω6c and/or C18 : 1ω7c. Strain 404T shows some typical characteristics among the members of genus Vibrio, while it can be clearly distinguished from the closely related type strains through genome analysis (average nucleotide identity and digital DNA-DNA hybridization values), fatty acid composition and a series of physiological and biochemical characteristics. On the basis of the polyphasic analysis, strain 404T is considered to represent a novel species of the genus Vibrio, for which the name Vibrio marinisediminis sp. nov., is proposed. The type strain is 404T (= MCCC 1H00367T = KCTC 62958T).

Regulation of ß1-integrin in autophagy and apoptosis of gastric epithelial cells infected with Helicobacter pylori.

Helicobacter pylori infection is an essential factor in the development of human gastric diseases, but its pathogenic mechanism is still unclear. In this work we have showed that, the LC3II levels were increased and ß1-integrin levels were decreased in H. pylori-positive human gastric tissue samples and H. pylori co-cultured GES-1 cells. There was significant upregulation of LC3II levels and downregulation of P62 levels in GES-1 cells after ß1-integrin knockdown co-cultured with H. pylori. This indicated that ß1-integrin downregulation promoted autophagy in GES-1 cells after H. pylori infection. The cell apoptosis rate and poly ADP-ribose polymerase (PARP) and caspase-3 activities were increased in GES-1 cells pretreated with 3-methyladenine (3-MA ) after H. pylori infection. Furthermore, there was a significant decrease in apoptosis of ß1-integrin knockdown GES-1 cells co-cultured with H. pylori; apoptosis was also downregulated in ß1-integrin knockdown- and 3-MA-treated GES-1 cells co-cultured with H. pylori. Correspondingly, PARP and caspase-3 activities were decreased in ß1-integrin knockdown cells co-cultured with H. pylori and ß1-integrin knockdown-3-MA-treated-1 cells with H. pylori infection. Thus, ß1-integrin is a novel autophagy and apoptosis regulator during H. pylori infection. However, inhibition of autophagy did not reverse the decrease in apoptosis caused by downregulation of ß1-integrin.

Halomonas marinisediminis sp. nov., A Moderately Halophilic Bacterium Isolated from the Bohai Gulf.

A novel Gram-stain-negative, moderately halophilic bacterium, designated strain 204T, was isolated from a marine sediment sample in the Bohai Gulf, Yellow Sea, China. Cells of strain 204T are aerobic, motile, cocci or short rods with two lateral flagella. Growth was observed at 15-40 °C (optimum, 30 °C), pH 6.0-9.0 (optimum, 7.0-7.5) and in the presence of 1.0-18.0% (w/v) NaCl (optimum, 3.0-8.0%). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 204T belonged to the genus Halomonas, showing highest sequence similarity to Halomonas alimentaria YKJ-16T (98.08%), followed by Halomonas sediminicola (97.47%), Halomonas fontilapidosi (97.14%), Halomonas halodenitrificans (96.98%), Halomonas ventosae (96.92%), and Halomonas shengliensis (96.85%). The draft genome is 3.8 Mb in length, containing 3673 protein-coding genes, 62 tRNA genes and 10 rRNA genes, and DNA G+C content is 62.7 mol%. Strain 204T contains phosphatidylglycerol, phosphatidylethanolamine, and diphosphatidylglycerol as the main polar lipids, and the predominant respiratory quinone was ubiquinone Q-9. The major cellular fatty acids (> 5%) are C18:1ω7c, C16:1ω7c and/or C16:1ω6c, C16:0 and C12:03-OH. Strain 204T was clearly distinguished from the closely related type strains through phylogenetic analysis, dDNA-DNA hybridization, fatty acid composition data and a range of physiological and biochemical characteristics comparisons. On the basis of the polyphasic analysis, strain 204T is considered to represent a novel species of the genus Halomonas, for which the name Halomonas marinisediminis sp. nov. is proposed. The type strain is 204T (= MCCC 1H00366T = KCTC 62957T).

Investigation on the role of gene hp0788 in Helicobacter pylori in infecting gastric epithelial cells.

Helicobacter pylori infection can cause a wide range of digestive diseases. Gene hp0788 encodes an outer membrane protein HofF, which can reduce the bacterial adherence to the GES-1 cells and affect pathogenesis of H. pylori. In this study, the role of hp0788 in H. pylori infection was further analyzed. RNA-seq data showed that two genes (hp0523 and hp0539), located on the cagPAI, were down-regulated in Δ0788 mutant. The changes were confirmed through qRT-PCR, and the expression of these two genes will be almost recovered to the normal level in complemented strain. These two genes, hp0523 and hp0539, are known to be necessary for integrated T4SS, which related to CagA translocation and IL-8 induction. In H. pylori infected assay, lower amount of phosphorylated CagA and lower induction of IL-8 were both detected in GES-1 cells infected by Δ0788 mutant, compared with the wild type strain. Meanwhile, these reductions almost recovered to the wild-type level in complemented strain. These results reveal that there is a correlation between hp0788 disruption and CagA/IL-8 decline. Deletion of CagA-encoding gene (hp0547) in Δ0788 mutant was further constructed. The double deleted mutant shows lower IL-8-inducing capability than Δ0788 mutant, indicated the correlation between deficiency of CagA and reduced IL-8 production. These results together imply that disruption of hp0788 might affect the efficiency of T4SS and CagA injection, then weaken the induction of IL-8 in infected GES-1 cells.

The regulatory role of C1q on Helicobacter pylori-induced inflammatory cytokines secretion in THP-1 cells.

C1q, as a LAIR-1 ligand, maintains monocytes quiescence and possess immunosuppressive properties. To understand the roles and molecular mechanisms, C1q mediated inflammation cytokines and several pivotal proteins in THP-1 cells after H. pylori infection were detected. The results showed that the expression of IL-8, IL-10, LAIR-1, phosphorylated/total JNK, phosphorylated/total p38-MAPK, phosphorylated/total AKT and phosphorylated/total NF-κB were up-regulated significantly in THP-1 cells after H. pylori infection. There was significant upregulation in IL-10 concentration, phosphorylated/total p38-MAPK and phosphorylated/total AKT, and downregulation in phosphorylated/total JNK in non-H. pylori infected THP-1 cells pretreated with C1q. C1q was also able to increase IL-8 and IL-10 production, and reduce LAIR-1 and phosphorylated/total p38-MAPK expression in pretreatment-C1q THP-1 cells after H. pylori infection. These results together indicated that H. pylori might induce IL-8 and IL-10 production through JNK, p38-MAPK, PI3K/AKT and NF-κB signaling pathway. C1q manipulate LAIR-1 to regulation IL-8 and IL-10 secretion in THP-1 cells after H. pylori infection through the p38-MAPK signaling pathway. This information is helpful to further understand the role and mechanisms of C1q on inflammation cytokines secretion in monocytes after H. pylori infection.

Thalassorhabdomicrobium marinisediminis gen. nov., sp. nov., a member of the family Hyphomonadaceae isolated from the Bohai Sea.

A novel Gram-stain-negative bacterium, designated strain BH-SD16T, was isolated from a marine sediment sample collected in the Bohai Sea. Cells of strain BH-SD16T are aerobic, non-flagellated oval-shaped rods, showing oxidase- and catalase-positive activities. Growth occurs between 15-45 °C (optimum, 30 °C), at pH 6.0-9.0 (pH 7.0-7.5) and with 1-10 % (w/v) NaCl (3.0 %). Strain BH-SD16T contains C18 : 1ω7c (49.2 %), C16 : 0 (17.7 %) and C18 : 1ω7c 11-methyl (16.6 %) as the predominant fatty acids and ubiquinone-10 as the major respiratory quinone. The major polar lipids comprise phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, diphosphatidylglycerol and two glycolipids. The size of the draft genome is 3 442 538 bp, including 3213 protein-coding genes, 40 tRNA genes and three rRNA genes, and the DNA G+C content is 63.4 mol%. Strain BH-SD16T shows the highest 16S rRNA gene sequence similarity to Pseudooctadecabacter jejudonensis (95.7 %), strains of the genus Octadecabacter(95.4-95.6 %) and strains of the genus Loktanella(93.8-95.4 %). Phylogenetic trees based on 16S rRNA gene sequences show that strain BH-SD16T forms a distinct lineage within the family Hyphomonadaceae, which is also confirmed in the multigenic phylogenetic tree calculated by RAxML. Based on the results of phenotypic, chemotaxonomic and phylogenetic analysis, strain BH-SD16T is considered to represent a novel genus and species in the family Hyphomonadaceae, for which the name Thalassorhabdomicrobium marinisediminis gen. nov., sp. nov. is proposed. The type strain is BH-SD16T (=CCTCC AB 2017073T=KCTC 62201T).

Detection of Neutralizing Antibodies in HIV-1 Patients on Antiretroviral Treatment for Over Ten Years.

BACKGROUND: Recently, many broadly applicable and potent neutralizing antibodies have been screened from HIV-1-infected patients. However, all these effective neutralizing antibodies were isolated from patients naive to anti-retroviral treatment (ART). METHODS: To better understand the induction of neutralizing antibodies in patients on ART, we screened 3 patients with an over ten-year infection history on ART from 350 patients in China for a cross-reactive neutralizing antibody response based on the use of different antigens and recombinant viruses. We studied the evolution of neutralizing activity in two patients during a one-year period with previously described recombinant viruses NL4-3 and SF162 using ELISA and neutralization assays. RESULTS: Antibodies purified from sera were able to react with recombinant virus antigens R2-gp120 and SF162-gp140 and neutralize SF162 recombinant virus but not NL4-3 recombinant virus. In addition, we observed a significant increase in the neutralizing response of immunoglobulin G (IgG) isolated from the serum sample in Patient 1 and compared it with the serum from Patient 1 six months ago. CONCLUSIONS: We thus confirm the possibility of production of neutralizing antibodies in patients infected for over ten years on ART, and it is possible over time of the improvement of HIV-1 potent neutralizing activity associated with viremia and immune reconstruction.

Aureibaculum marinum gen. nov., sp. nov., a Novel Bacterium of the Family Flavobacteriaceae Isolated from the Bohai Gulf.

A novel Gram-stain-negative bacterium, designated strain BH-SD17T, was isolated from a marine sediment sample in the Bohai Gulf, Yellow Sea, China. Cells of strain BH-SD17T are aerobic, yellow-colored, non-flagellated rods. Growth occurs between 15 and 40 °C (optimum, 30 °C), at pH 6.0-8.5 (optimum, 7.5) and with 1.0-8.0% (w/v) NaCl (optimum, 3.0%). Strain BH-SD17T contains phosphatidylethanolamine and two unidentified lipids as the major polar lipids. The predominant fatty acids are iso-C15:0 (28.5%), iso-C15:1 G (24.4%), and iso-C17:0 3-OH (12.3%). The major respiratory quinone is MK-6. Strain BH-SD17T shows moderate 16S rRNA gene sequence similarity to existing identified strains, is most closely related to the genera Lutimonas (92.1-92.4%), Lutibacter (91.6-92.3%), and Taeania (91.9%). Phylogenetic trees based on 16S rRNA gene sequences show that strain BH-SD17T forms a distinct lineage within the family Flavobacteriaceae. Based on the results of phenotypic, chemotaxonomic and phylogenetic analysis, strain BH-SD17T is considered to represent a novel genus and species in the family Flavobacteriaceae, for which the name Aureibaculum marinum is proposed. The type strain is BH-SD17T (=CCTCC AB 2017072T=KCTC 62204T).

Pelagivirga sediminicola gen. nov., sp. nov. isolated from the Bohai Sea.

A Gram-stain-negative bacterium, strain BH-SD19T, that was isolated from a marine sediment sample collected from the Bohai Sea, was subjected to a polyphasic taxonomic study. Cells of BH-SD19T are non-flagellated, non-gliding, oval-shaped rods, 0.5-1.0 µm wide and 1.0-2.0 µm long. BH-SD19T is strictly aerobic, and oxidase- and catalase-positive. Growth occurs at 15-40 °C (optimum 35 °C), at pH 6.0-8.5 (optimum 7.0-7.5) and with 1-10 % (w/v) NaCl (optimum 2 %). The predominant fatty acids are C19 : 0cyclo ω8c (46.5 %), C16 : 0 (20.3 %) and C18 : 1ω7c and/or C18 : 1ω6c (10.6 %). The major respiratory quinone is Q-10. The major polar lipids are phosphatidylglycerol, phosphatidylethanolamine and an unidentified phospholipid. The DNA G+C content is 64.0 mol%. BH-SD19T shows the highest 16S rRNA sequence similarity to Pontibaca methylaminivorans (95.2 %) and strains of species of the genus Roseovarius(93.4-95.2 %). Sequence similarity values between BH-SD19T and other phylogenetically related species are all below 95.0 %. Phylogenetic trees based on 16S rRNA gene sequences indicate that BH-SD19T forms a distinct lineage and does not join any known genera in the trees. Phenotypic, chemotaxonomic and phylogenetic data indicate that BH-SD19T represents a novel genus and species in the family Rhodobacteraceae, for which the name Pelagivirga sediminicola gen. nov., sp. nov. is proposed. The type strain is BH-SD19T (=CCTCC AB 2017074T=KCTC 62202T).

PI3K signaling pathways modulated white spot syndrome virus (WSSV) replication in Procambarus clarkii.

The PI3K/AKT signaling pathway is commonly exploited to regulate viral replication and affect the fate of infected cells. In the present study, a PI3K-specific inhibitor (LY294002) was employed to pretreat crayfish to evaluate the effects of PI3K/AKT signaling pathway in WSSV replication. The results showed that the WSSV copy numbers in crayfish pretreated with LY294002 were significantly lower than those in Tris-HCl pretreatment crayfish on the sixth and tenth day after WSSV infection. In semigranular cells, the apoptosis rates were up-regulated on the third day post-WSSV infection, and a significantly lower proportion of apoptosis cells were observed in LY294002-pretreatment group. The expression level of Bax, Bax inhibitor-1 and lectin mRNA in haemocytes of crayfish were increased after WSSV infection. After the secondary stimulation with Tris-HCl, the Bax expression level in LY294002-pretreatment crayfish was significantly higher than that of crayfish pretreated with Tris-HCl on the third or sixth day, but the Toll and lectin mRNA expression decreased significantly on the third, sixth and tenth day. The Bax mRNA expression levels in LY294002-WSSV group were significantly higher than those in Tris-HCl-WSSV group on the third and tenth day. The Bax inhibitor-1 mRNA expression levels in LY294002-WSSV group were significantly lower than those in Tris-HCl-WSSV crayfish on the third day. These results together indicated that the hosts PI3K/AKT signaling pathway play positive roles in WSSV replication through the balance between host cell apoptois and innate immune responses. This information is helpful to further understand the role of PI3K/AKT signaling pathway on WSSV replication in Decapoda crustaceans.

The leukocyte-associated immunoglobulin (Ig)-like receptor-1 modulating cell apoptosis and inflammatory cytokines secretion in THP-1 cells after Helicobacter pylori infection.

OBJECTIVE: Helicobacter pylori is a Gram-negative, microaerophilic bacteria usually found in the stomach, which may evade its host's immune system and present long-term symptoms in affected individuals. This study aimed to evaluate the functional role of leukocyte-associated immunoglobulin (Ig)-like receptor-1 (LAIR-1) in the strategies and underlying molecular mechanisms by which H. pylori escapes the host's immune responses. METHODS: LAIR-1 knockdown THP-1 cells were used to detect cell apoptosis, cell proliferation, interleukin-8 (IL-8), IL-10, and activation of intracellular signaling induced by H. pylori. RESULTS: Cell apoptosis, cell proliferation, IL-8, and IL-10 were increased in THP-1 cells after 24 h of H. pylori infection. Functional analysis indicated LAIR-1 silencing obviously inhibited the phosphorylation of IκBα, eIF2α, JNK, and Smad2 in the THP-1 after H. pylori infection. In addition, there were no significant differences in proliferation rates between control siRNA group and LAIR-1 siRNA group regardless of whether THP-1 cells were infected by H. pylori. CONCLUSION: These results together indicated that LAIR-1 modulated cell apoptosis and inflammatory cytokines secretion in THP-1 cells, which might help sustain inflammation and prevent removal of the bacteria by the immune responses.

Functional study of gene hp0169 in Helicobacter pylori pathogenesis.

Many virulence genes have been reported to play important roles in Helicobacter pylori pathogenesis. However the detailed mechanisms of many of them have not been completely clear. In this study, we found gene hp0169, encoding a putative collagenase (HpPrtC), was involved in pathogenesis of H. pylori. Recombinant HpPrtC shows activities to both native and heat-denatured collagens. This result indicated that HpPrtC may act as a virulence factor to help the bacterium colonize in their host stomach by degrading surrounding collagens. hp0169 was deleted by homologous recombination to study its function in bacterium-host cell interaction. For the pathogenic functions on the host cells, the hp0169 mutant exhibits no significant changes on inducing apoptosis of GES-1 cells. However, the viability and proliferation rate of GES-1 cells infected with mutant strain were higher than the cells infected with wild-type strain. These results indicated that except for its collagenolytic activity, HpPrtC might participate in H. pylori pathogenesis through an additional pathway. Functional studies on hp0169 involved in pathogenesis would shed light on deep understanding of the pathogenic mechanism of H. pylori.

Functional profile of gastric epithelial cells infected with Helicobacter pylori strains.

Helicobacter pylori infection represents a key factor in the etiology of various gastro-duodenal diseases, ranging from chronic gastritis to the development of peptic ulcer disease and end-stage gastric cancer. In the present study, the 26695 and SS1 strains of H. pylori were used to study the differential functional profiles of gastric epithelial cells infected with H. pylori. The apoptosis rates in GES-1 cells were significantly increased 3, 12 and 24 h after H. pylori 26695 and SS1 infection. Moreover, apoptosis by cells infected with the H. pylori 26695 strain was significantly higher than cells infected with the SS1 strain of H. pylori. No significant changes in the proliferation rates of GES-1 cells were observed after H. pylori 26695 or SS1 infection at any time during the experimental period. Exposure to H. pylori 26695 and SS1 induced a significant decline in the adhesion rates of GES-1 cells in a time-dependent manner. Furthermore, H. pylori 26695 infection increased migration of GES-1 cells every hour during the whole experimental period compared with control cells. However, GES-1 cells infected with the H. pylori SS1 strain exhibited migration rates almost stable and comparable to those of control cells. These results indicate that the gastric epithelial cells respond differently depending on the H. pylori strains. This study indicates that the development of different gastric-related diseases may be a H. pylori strain-specific response.