Three Novel Lantibiotics, Ticins A1, A3, and A4, Have Extremely Stable Properties and Are Promising Food Biopreservatives.

Lantibiotics are antimicrobial peptides with potential applications as the next generation of antimicrobials in the food industry and/or the pharmaceutical industry. Nisin has successfully been used as a food preservative for over 40 years, but its major drawback is its limited stability under neutral and alkaline pH conditions. To identify alternatives with better biochemical properties, we screened more than 100 strains of the Bacillus cereus group. Three novel lantibiotics, ticins A1 (4,062.98 Da), A3 (4,048.96 Da), and A4 (4,063.02 Da), which were highly thermostable (121°C for 30 min) and extremely pH tolerant (pH 2.0 to 9.0), were identified in Bacillus thuringiensis BMB3201. They all showed potent antimicrobial activities against all tested Gram-positive bacteria and greater activities than those of nisin A against Bacillus cereus and Listeria monocytogenes, two important foodborne pathogens. These three novel lantibiotics, with their extremely stable properties and potent antimicrobial activities, have the potential for use as biopreservatives.

ApnI, a transmembrane protein responsible for subtilomycin immunity, unveils a novel model for lantibiotic immunity.

Subtilomycin was detected from the plant endophytic strain Bacillus subtilis BSn5 and was first reported from B. subtilis strain MMA7. In this study, a gene cluster that has been proposed to be related to subtilomycin biosynthesis was isolated from the BSn5 genome and was experimentally validated by gene inactivation and heterologous expression. Comparison of the subtilomycin gene cluster with other verified related lantibiotic gene clusters revealed a particular organization of the genes apnI and apnT downstream of apnAPBC, which may be involved in subtilomycin immunity. Through analysis of expression of the apnI and/or apnT genes in the subtilomycin-sensitive strain CU1065 and inactivation of apnI and apnT in the producer strain BSn5, we showed that the single gene apnI, encoding a putative transmembrane protein, was responsible for subtilomycin immunity. To our knowledge, evidence for lantibiotic immunity that is solely dependent on a transmembrane protein is quite rare. Further bioinformatic analysis revealed the abundant presence of ApnI-like proteins that may be responsible for lantibiotic immunity in Bacillus and Paenibacillus. We cloned the paeI gene, encoding one such ApnI-like protein, into CU1065 and showed that it confers resistance to paenibacillin. However, no cross-resistance was detected between ApnI and PaeI, even though subtilomycin and paenibacillin share similar structures, suggesting that the protection provided by ApnI/ApnI-like proteins involves a specific-sequence recognition mechanism. Peptide release/binding assays indicated that the recombinant B. subtilis expressing apnI interacted with subtilomycin. Thus, ApnI represents a novel model for lantibiotic immunity that appears to be common.

Mutation analysis of DC-SIGN promoter in chronic hepatitis B patients.

OBJECTIVE: To investigate whether there is mutation in DC-SIGN promoter region in patients with chronic hepatitis B (CHB) and healthy persons previously infected with hepatitis B virus (HBV) and to explore the relationship between the mutation in dendritic cell-specific intercellular adhension molecule-3-grabbing nonintegrin (DC-SIGN) promoter region and HBV. METHODS: The studied population was composed of two cohorts: 47 CHB patients and 20 healthy persons previously infected with HBV. The mutation in DC-SIGN promoter region was detected with PCR, single-stranded conformational polymorphism and heteroduplex analysis, cloning, sequencing and aligning the published DC-SIGN promoter sequence. RESULTS: The characteristic mutation within DC-SIGN promoter region in HBV infected individuals was observed. In the DC-SIGN promoter region, 4 hot spot mutations located in positions -139, -142, -222, and -336 were observed in the CHB patients, but only 1 spot mutation located in position -139 was observed in the healthy persons previously infected with HBV. The -336C which was absent in the healthy persons previously infected with HBV was shown in 11 CHB patients (23.40%). The -139T was far more frequent in the healthy persons previously infected with HBV (100%) than in the CHB patients (34.04%). CONCLUSION: In the DC-SIGN promoter region, -336C may be a genetic risk factor for developing CHB, but -139T may be associated with protection against HBV.

Clinical characteristics and therapeutic analysis of invasive fungal infection in chronic severe hepatitis patients.

OBJECTIVE: To investigate clinical features and antifungal therapeutic effect of chronic severe hepatitis (CSH) patients with invasive fungal infection (IFI), and to improve the diagnosis and treatment. METHODS: Clinical manifestation, blood routine, imageology and mycetology characteristic, antifungal treatment perscription and therapeutic effect of 79 CSH patients with IFI were retrospectively analyzed. Antifungal therapeutic effect was compared between fluconazole and voriconazole. RESULTS: Thirteen (16.5%) patients received glucocorticoid or other immunodepressants for a relatively long time, 40 (50.6%) patients had invasive operation, and 61 (77.2 %) patients were administered 1-6 kinds of broad-spectrum antibiotics. Seventy-three patients had fever. Leucocytes and neutrophilic granulocyte increased in 96.2% of the patients. Lung (31.6%), intestinal tract (26.2%) and oral cavity (14%) infections were common. Fungus was found in 70.9% of the patients. Candida albicans (40.9%) and aspergillus (21.1%) were often seen. Halo signs and crescent signs on lung CT were relatively specific in 40% of the patients with fungal pneumonia. Voriconazole was more effective than fluconazole(71.4% vs. 39.0%, P<0.05). Twelve patients with lung aspergillus infection were administered voriconazole, 8 (66.7%) patients of whom was effective, and the other 4 (33.3%) patients died. CONCLUSION: There are high risk factors in major CSH patients with IFI. The most common clinical manifestations of CSH patients with IFI are fever, leukocytosis, lung and intestinal tract infection. Candida albicans and aspergillus infection are common. Voriconazole is more effective than fluconazole, and can increase the survival rate of CSH patients with IFI.

Genome-wide Dissection of Co-selected UV-B Responsive Pathways in the UV-B Adaptation of Qingke.

Qingke (Tibetan hulless barley) has long been cultivated and exposed to long-term and strong UV-B radiation on the Tibetan Plateau, which renders it an ideal species for elucidating novel UV-B responsive mechanisms in plants. Here we report a comprehensive metabolite profiling and metabolite-based genome-wide association study (mGWAS) using 196 diverse qingke and barley accessions. Our results demonstrated both constitutive and induced accumulation, and common genetic regulation, of metabolites from different branches of the phenylpropanoid pathway that are involved in UV-B protection. A total of 90 significant mGWAS loci for these metabolites were identified in barley-qingke differentiation regions, and a number of high-level metabolite trait alleles were found to be significantly enriched in qingke, suggesting co-selection of various phenylpropanoids. Upon dissecting the entire phenylpropanoid pathway, we identified some key determinants controlling natural variation of phenylpropanoid content, including three novel proteins, a flavone C-pentosyltransferase, a tyramine hydroxycinnamoyl acyltransferase, and a MYB transcription factor. Our study, furthermore, demonstrated co-selection of both constitutive and induced phenylpropanoids for UV-B protection in qingke.

Endophyte Bacillus subtilis evade plant defense by producing lantibiotic subtilomycin to mask self-produced flagellin.

Microbes can enter into healthy plants as endophytes and confer beneficial functions. The entry of commensal microbes into plants involves penetrating plant defense. Most mechanisms about overcoming plant defense are focused on adapted pathogens, while the mechanism involved in beneficial endophyte evades plant defense to achieve harmonious commensalism is unclear. Here, we discover a mechanism that an endophyte bacterium Bacillus subtilis BSn5 reduce to stimulate the plant defensive response by producing lantibiotic subtilomycin to bind self-produced flagellin. Subtilomycin bind with flagellin and affect flg22-induced plant defense, by which means promotes the endophytic colonization in A. thaliana. Subtilomycin also promotes the BSn5 colonization in a distinct plant, Amorphophallus konjac, where the BSn5 was isolated. Our investigation shows more independent subtilomycin/-like producers are isolated from distinct plants. Our work unveils a common strategy that is used for bacterial endophytic colonization.

Immune responses of recombinant adenovirus co-expressing VP1 of foot-and-mouth disease virus and porcine interferon alpha in mice and guinea pigs.

Foot-and-mouth disease (FMD) is a highly contagious and economically devastating vesicular disease of cloven-hoofed animals. In this study, we constructed and characterized the immune responses and vaccine efficacy conferred by the recombinant adenovirus co-expressing VP1 of FMDV and porcine interferon alpha as fusion protein (rAd-pIFNalpha-VP1). Six groups of female BALB/c mice each with 18 were inoculated subcutaneously twice 2-week intervals with the recombinant adenoviruses. The results showed that the levels of humoral and cell-mediated immune responses in the group inoculated with rAd-pIFNalpha-VP1 were significantly higher than those in the group inoculated with rAd-VP1+rAd-pIFNalpha (P<0.05). Then four groups of guinea pigs each with six were inoculated two times at 2-week intervals intramuscularly with rAd-pIFNalpha-VP1, commercial inactivated FMD vaccine, wild-type adenovirus (wtAd) or PBS, and the protective efficacy of rAd-pIFNalpha-VP1 was determined. The results indicated that all the guinea pigs vaccinated with rAd-pIFNalpha-VP1 as well as inactivated FMD vaccine were protected from FMDV challenge, even though the levels of neutralizing antibodies (1:32-1:40) of the animals vaccinated with rAd-pIFNalpha-VP1 was lower than that in the group inoculated with inactivated FMD vaccine (1:64-1:128). It demonstrated that the newly recombinant adenovirus rAd-pIFNalpha-VP1 might further be an attractive candidate vaccine for preventing FMDV infection in swine.

miR-197 Expression in Peripheral Blood Mononuclear Cells from Hepatitis B Virus-Infected Patients.

BACKGROUND/AIMS: This study aimed to investigate the microRNA (miRNA) expression profiles in peripheral blood mononuclear cell (PBMC) of hepatitis B virus (HBV)-infected patients with different clinical manifestations and to analyze the function of miR-197. METHODS: PBMC miRNA expression profiles in 51 healthy controls, 70 chronic asymptomatic carriers, 107 chronic hepatitis B patients, and 76 HBV-related acute on chronic liver failure patients were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). miR-197 mimic and inhibitor were transfected in THP-1 cells. qRT-PCR and ELISA for interleukin (IL)-18 mRNA and protein levels were performed, respectively. RESULTS: The microarray analysis revealed that 17 PBMC miRNA expression profiles (12 miRNAs downregulated and five miRNAs upregulated) differed significantly in HBV-induced liver disease patients presenting with various symptoms. The qRT-PCR results suggested that the PBMC miR-197 levels regularly decreased as the severity of liver disease symptoms became aggravated. IL-18, a key regulator in inflammation and immunity, was inversely correlated with miR-197 levels. Bioinformatic analysis indicated that IL-18 was a target of miR-197. Exogenous expression of miR-197 could significantly repress IL-18 expression at both the mRNA and protein levels in THP-1 cells. CONCLUSIONS: We concluded that multiple PBMC miRNAs had differential expression profiles during HBV infection and that miR-197 may play an important role in the reactivation of liver inflammation by targeting IL-18.