Adjuvant activity of Pasteurella multocida A strain,Pasteurella multocida B strain and Salmonella typhimurium bacterial DNA on cellular and humoral immunity responses against Pasteurella multocida specific strain infections in Balb/c mice

Objective: To evaluate the effects of Pasteurella multocida(P. multocida) vaccines on the expression and release of antibodies, interleukin(IL)-6 and IL-12 by serum. Methods: Balb/c mice were immunized with two formalin and iron inactivated vaccine doses within 2 weeks. The vaccines were adjuvant with P. multocida A strain, P. multocida B strain and Salmonella typhimurium bacterial DNA(AbDNA, BbDNA and SbDNA for short, respectively). The animals were challenged 4 weeks after immunization. Blood of mice was collected to detect the change of specific antibody, IL-6, and IL-12 using ELISA. Results: The specific antibody and interleukins in the immunized group increased significantly compared to the control mice after vaccination and challenge(P<0.05). The highest release of these cytokines was obtained by P.multocida inactivated with iron and adjuvant with AbDNA at a concentration of 25 μg/mL. The antibody titer peak was 0.447 in mice vaccinated with iron-killed whole-cell antigen adjunct with AbDNA. The time-courses of release showed that bacterial DNA was able to stimulate IL-6 and IL-12 production more than alum(P<0.05). Conclusions: Our findings introduce that bacterial DNA is capable of releasing an immunological response with several cytokines.These indicate that bacterial DNA entrapped with killed P. multocida antigen is a new and effective adjuvant to enhance specific immunity and resistance of animal against the infectious pathogen, which could simplify the development of highly promising strong adjuvant.

An evaluation of multiple annealing and looping based genome amplification using a synthetic bacterial community

The low biomass in environmental samples is a major challenge for microbial metagenomic studies. The amplification of a genomic DNA was frequently applied to meeting the minimum requirement of the DNA for a high-throughput next-generation-sequencing technology. Using a synthetic bacterial community, the amplification efficiency of the Multiple Annealing and Looping Based Amplification Cycles（MALBAC） kit that is originally developed to amplify the single-cell genomic DNA of mammalian organisms is examined. The DNA template of 10 pg in each reaction of the MALBAC amplification may generate enough DNA for Illumina sequencing. Using 10 pg and 100 pg templates for each reaction set, the MALBAC kit shows a stable and homogeneous amplification as indicated by the highly consistent coverage of the reads from the two amplified samples on the contigs assembled by the original unamplified sample. Although Genome Plex whole genome amplification kit allows one to generate enough DNA using 100 pg of template in each reaction, the minority of the mixed bacterial species is not linearly amplified. For both of the kits, the GC-rich regions of the genomic DNA are not efficiently amplified as suggested by the low coverage of the contigs with the high GC content. The high efficiency of the MALBAC kit is supported for the amplification of environmental microbial DNA samples, and the concerns on its application are also raised to bacterial species with the high GC content.

Effect of a Natural Inulin-Containing Product, “Kikuimo Extract” on Intestinal Microbes and Gene Expression in the Liver and Adipose Tissue of Menopausal Monkeys

Inulin is a soluble and indigestible fiber derived from natural plants such as Jerusalem artichoke (Helianthus tuberosus), “Kikuimo”. In the current study, a nutrigenomics approach was utilized to evaluate the in vivo function of “Kikuimo Extract” (KE) in ovariectomized cynomolgus macaque, a post-menopausal non-human primate model. KE was administered orally before feeding, for 3 months for the following examinations: 1) the effect of KE on intestinal microbes was examined by quantitative analyses of the intestinal bacteria using real-time PCR with DNA extracted from monkey feces;2) the effect of KE on gene expression was investigated by real-time RT-PCR using RNA extracted from both the liver and adipose tissue of the monkeys. KE administration modulated menopause-mediated altered microbes to increase Lactobacilli, Veillonella, and Bacteroides in all monkeys. KE administration regulated the altered expression of functional genes, SCAP, LDLR, and LXRA (lipid metabolism);GLUT-4 (glucose transport);CYP1A1 and CYP1A2 (drug metabolism);and CYP-17-2 and CYP-19-2 (E2 synthesis) in the menopausal monkeys. In menopausal monkeys, KE showed potent prebiotic effect on beneficial microflora and regulating effect on altered expression of functional genes associated with metabolism and E2 production. Thus, KE appears to be a practical functional food that alleviates the altered conditions of intestinal microbes and gene expression in the liver and adipose tissue in a menopausal state.

Development of pretreatment protocol for DNA extraction from biofilm attached to biologic activated carbon(BAC)granules

The biologic activated carbon(BAC)process is widely used in drinking water treatments.A comprehensive molecular analysis of the microbial community structure provides very helpful data to improve the reactor performance.However,the bottleneck of deoxyribonucleic acid(DNA)extraction from BAC attached biofilm has to be solved since the conventional procedure was unsuccessful due to firm biomass attachment and adsorption capacity of the BAC granules.In this study,five pretreatments were compared,and adding skim milk followed by ultrasonic vibration was proven to be the optimal choice.This protocol was further tested using the vertical BAC samples from the full-scale biofilter of Pinghu Water Plant.The results showed the DNAyielded a range of 40μg·g^(-1) BAC(dry weight)to over 100μg·g^(-1) BAC(dry weight),which were consistent with the biomass distribution.All results suggested that the final protocol could produce qualified genomic DNA as a template from the BAC filter for downstream molecular biology researches.

An E. coli SOS-EGFP biosensor for fast and sensitive detection of DNA damaging agents

An E. coli SOS-EGFP biosensor which expresses enhanced green fluorescent protein as a reporter protein under the control of recA gene promoter in SOS response was constructed for detection of DNA damage and evaluation of DNA damaging chemicals. The chemicals that may cause substantial DNA damage will trigger SOS response in the constructed bacterial biosensor, and then the reporter egfp gene under the control of recA promoter is stimulated to express as a fluorescent protein, allowing fast and sensitive fluorescence detection. Interestingly, this biosensor can be simultaneously applied for evaluation of genotoxicity and cytotoxicity. The SOS-EGFP bacterial biosensor provides a sensitive, specific and simple method for detecting known and potential DNA damaging chemicals.