Abstract:Abstract:［Objective］ We studied the system immunofuctions of two Bifidobacterium strains isolated from food．［Methods］There were 10 SPF BALB /c mice in each group．The control group was given only sterile skim milk．The positive control group was given sterile skim milk containing commercial strain BB-12．The treatment group was given sterile skim milk containing different dosages of B．adolescentis BB-2 or B．longum BB-3．The immune parameters including cellular immunity (delayed-type hypersensitivity ［DTH］，splenic lymphocyte proliferation and natural killer［NK］ cell activity)，humoral immunity (serum hemolytic activity in immunized animals)，and nonspecific immunity (peritoneal macrophages phagocytsis) were measured．［Results］Ingestion of B．adolescentis BB-2 or B．longum BB-3 could increase the DTH response． Macrophage phagocytsis was also enhanced，while activities of the NK cells and levels of the serum hemolysin were also significantly higher than that in the control group． There was a significant increase in splenic lymphocyte proliferation in bifidobacteria treated mice compared to the control．［Conclusion］ Ingestion of B．adolescentis BB-2 or B．longum BB-3 could enhance both innate and acquired immunity in healthy BALB/c mice．

Abstract:Abstract: [Objective] We developed a sensitive method to detect Escherichia coli O157:H7 based on enhancement with immuno-nanoparticles. [Method] About 10 nm ultrafine immunomagnetic particles were prepared by a co-precipitation method, about 20 nm immuno-colloid-gold was prepared by sodium citrate reduction. The immunosensor was fabricated by using Protein A from Staphylococcus aureus (SPA) for the antibody immobilization. Two immuno-nanoparticles by two antibodies were used to amplify frequency changing. [Result] The most suitable immobilization concentration and time for SPA was 1.2 mg/ml and 40 min, and dose for the antibody was 1.0 mg/ml and 60 min. With the signal amplification of the two immuno-nanoparticles, the detection limit of E. coli O157 : H7 was increased from 104 colony-forming units (cfu) /mL to 101 cfu/mL. [Conclusion] The prepared immuno-nanoparticles might be used to significantly amplify the frequency signal of the piezoelectric immunosensor and improve the detect sensitivity.

Abstract:[Objective] We evaluated the immunoenhancement effect and mechanism of pig spleen transfer factor (TF) on Newcastle disease virus (NDV) La Sota strain attenuated vaccine to provide a theoretical basis for the prevention and control of Newcastle disease (ND). [Methods] We inoculated La Sota strain alone and La Sota combined with TF into specific pathogen free (SPF) chickens at four different doses, and challenged SPF chickens by reference virulent NDV strain F48E9 (104.7 ELD50) 14 days post vaccination. In addition, we determined the concentrations of IL-6, IL-10, IL-16, and IL-21 in chicken peripheral blood by protein chip technology, the hemagglutination inhibition (HI) antibody titer by HI assay, and the viremia level of F48E9 by RT-PCR. [Results] The challenge test showed that the protection rates of vaccination with La Sota strain alone at the doses of 105.17, 104.17, 103.17, and 102.17 EID50 were 100%, 55%, 0%, and 0%, respectively, and the median protective dose (PD50) was 12 023 EID50. The protection rates of vaccination with La Sota strain combined with TF at the corresponding doses were 100%, 75%, 0%, and 0%, respectively, and the PD50 was 6 918 EID50. The mortality of control group (non-immunized but challenged) and blank group (non-immunized and non-challenged) were 100% and 0%. Upon vaccination at the dose of 104.17 EID50, the IL-6, IL-10, IL-21, and ND HI antibody titer (log2x) of the chicken exposed to combined vaccination increased at most by 254.95 pg/mL, 62.10 pg/mL, 1.51 pg/mL, and 2.6 (P<0.01), respectively, compared with those in the chicken vaccinated with La Sota strain alone. After challenge, the IL-10, IL-16, IL-21, and the viremia levels in the chicken under combined vaccination decreased at most by 428.61 pg/mL, 167.81 pg/mL (P<0.01), 1.48 pg/mL (P<0.01), and 20%, respectively, compared with those in the chicken vaccinated with La Sota strain alone. [Conclusion] TF improves the immune protection rate of NDV attenuated La Sota strain vaccine, the immune response mediated by IL-6, IL-10, and IL-21, and the ND HI antibody titer. In addition, TF reduces the PD50, the inflammatory responses mediated by IL-16 and IL-21, the inhibition of immune response mediated by IL-10, and the viremia after challenge. It is clear that TF has a good immunoenhancement effect on the La Sota strain attenuated vaccine, which will provide a reference for research and development of vaccine adjuvant as well as prevention and control of ND.

Abstract:Microbial drug is a large family of small molecules with unusual structural features and potent bioactivities. The production of microbial drug is crucial for its subsequent development and cost. Traditional breeding strategies for microbial drug production have been demonstrated to be remarkably effective, but they have also indicated the drawback of exceptional randomness and high cost. Synthetic biology has recently promised a revival for the rational enhancement of microbial drugs. In this review, we mainly discuss the recent progress from the aspects of promoter engineering, precursor supply, genome shuffling and etc., to delineate the application of the synthetic biology strategies to enhance the production of the microbial drugs, particularly, produced by actinomycetes.

Abstract:Estuaries are the transition zones between land and sea, and the health of the ecosystem is essential to the surrounding residents and the sustainable economic development. In recent years, amid the rapid development of the cities nearby, a large number of the permanent polycyclic aromatic hydrocarbons (PAHs) have accumulated in the sediments of estuaries, posing a threat to the health of the aquatic ecosystems. As a result, the degradation and transformation of PAHs have attracted the interest of scholars. According to previous studies, Pseudomonadota, Actinobacteria, and Bacillota dominate the PAHs-degrading bacteria in sediments of main estuaries (Pearl River Estuary, Yangtze River Estuary, Liaohe River Esturay, and Haihe River Estuary) in China, among which Klebsiella, Bacillus, and Pseudomonas have been frequently reported. Bacteria degrade PAHs in estuarine sediments mainly through the anaerobic pathway which is characterized by low efficiency. Low oxygen and high salinity in estuarine sediments are unfavorable for the bacterial degradation of PAHs, and the changeable temperature and pH result in uncertain efficiency of bioremediation. The addition of surfactants, nutrients, and exogenous electron receptors and the co-metabolism can promote the bacterial degradation of PAHs in sediments. At the moment, most studies have been carried out in laboratory, but the environmental conditions of estuarine sediments are complex. Therefore, it is suggested to screen PAHs-degrading strains according to the environmental characteristics of estuarine sediments in the future, and flexibly formulate strategies to enhance the degradation according to the actual situation. This review is expected to serve as a reference for further screening and utilization of indigenous PAHs-degrading bacteria in the sediments of major estuaries in China.

Abstract:Abstract：[Objective]The purpose of this research is trying to uncover the homology between two velogenic genotype III Newcastle disease virus (NDV) isolates with NDV strain Mukteswar, which was commonly used as vaccine in China. [Methods]The full-length genome of NDV isolates, JS/7/05/Ch and JS/9/05/Go, were determined by RT-PCR and then analyzed. [Results]The full-length genome of 2 genotype III velogenic NDV isolates shared 99.7% nucleotide identity with that of Mukteswar. The results of alignment of 6 viral genes showed that JS/7/05/Ch and JS/9/05/Go shared nucleotide and amino acid identities of 99.6 %～99.9% and 98.8%～99.8% with that of Mukteswar, respectively. Furthermore, the IVPI score of JS/7/05/Ch and JS/9/05/Go was 2.18 and 1.33, remarkablely higher than that of Mukteswar, while the 3 NDV strains shared the consensus cleavage site of virulent NDV strains (112RRQRRF117). Virulence of NDV is mainly determined by the amino acid sequence of the fusion (F) protein cleavage site, since host proteases that cleave the F protein of virulent strains are present in more tissues than those that cleave the F protein of lentogenic strains. However, 3 NDV strains with same F protein cleavage site showed different virulence. The entire genomic sequence of JS/7/05/Ch, JS/9/05/Go and Mukteswar was further analyzed. Three strains shared some gene-start signal, gene-end signal, intergenic region and six highly identical viral genes. Most amino acid differences among JS/7/05/Ch, JS/9/05/Go and Mukteswar were found in the predicted HN and L protein, and the predicted NP, P, V, W, M and even F protein had few amino acid differences. [Conclusion]First, it is concluded that field isolates JS/7/05/Ch and JS/9/05/Go are derived from Mukteswar and more attention must be paid to the virulence enhancement of vaccine strains. Second, it is proposed that the differences in the amino acid sequence of HN and L protein may give rise to the significant virulence differences between two NDV isolates and Mukteswar.