南通沿海滩涂耐盐植物重金属抗性内生细菌的筛选及生物多样性

【目的】沿海滩涂耐盐植物重金属抗性内生细菌的筛选及其促生长潜在能力的研究有助于我们获得一些能够耐受并促进耐盐植物在被Cd2+、Pb2+、Hg2+、Cu2+,Zn2+等重金属离子污染的贫瘠的沿海滩涂上正常生长的菌株,达到既能够利用广袤的滩涂生物资源产生经济价值又能够净化生态环境的目的。【方法】以江苏南通沿海滩涂地区的4种耐盐植物为材料,采用稀释平板涂布法从中分离得到45株内生细菌,从中挑取23株代表性的菌株,对其进行抗重金属Cu2+、Pb2+、Cd2+、Zn2+,Hg2+的活性筛选;固氮、解磷、吲哚乙酸(IAA)的产生、1-氨基环丙烷-1-羧酸(ACC)脱氨酶活性等促生指标以及NaCl耐受能力的筛选。【结果】发现分离所得的大多数细菌能够耐受高浓度的Cu2+以及Pb2+,但是对Cd2+、Zn2+,Hg2+的耐受能力则较弱;26.1%的细菌具有固氮能力,21.7%的细菌具有解磷能力,60.9%的细菌能够产生IAA,39.1%的细菌含有ACC脱氨酶。对他们进行16S rRNA基因鉴定后发现,他们分属于芽胞杆菌属(Bacillus)、喜盐芽胞杆菌属(Halobacillus)、海洋芽胞杆菌属(Oceanobacillus)、微小杆菌属(Exiguobacterium)、沙雷氏菌属(Serratia)、短波单胞菌属(Brevundimonas)、弧菌属(Vibrio)、葡萄球菌属(Staphylococcus)共8个属,显示了丰富的多样性。其中菌株KLBMP 2432以及菌株KLBMP 2447为潜在的新种。【结论】沿海滩涂地区的耐盐植物内生细菌具有丰富多样的生物多样性以及促生长能力,且存在潜在的新种资源,并对重金属Cu2+,Pb2+具有较强的抗性。     

Proteomic signatures of human oral epithelial cells in HIV-infected subjects

The oral epithelium, the most abundant structural tissue lining the oral mucosa, is an important line of defense against infectious microorganisms. HIV infected subjects on highly active antiretroviral therapy (HAART) are susceptible to comorbid viral, bacterial and fungal infections in the oral cavity. To provide an assessment of the molecular alterations of oral epithelia potentially associated with susceptibility to comorbid infections in such subjects, we performed various proteomic studies on over twenty HIV infected and healthy subjects. In a discovery phase two Dimensional Difference Gel Electrophoresis (2-D DIGE) analyses of human oral gingival epithelial cell (HOEC) lysates were carried out; this identified 61 differentially expressed proteins between HIV-infected on HAART subjects and healthy controls. Down regulated proteins in HIV-infected subjects include proteins associated with maintenance of protein folding and pro- and anti-inflammatory responses (e.g., heat-shock proteins, Cryab, Calr, IL-1RA, and Galectin-3-binding protein) as well as proteins involved in redox homeostasis and detoxification (e.g., Gstp1, Prdx1, and Ero1). Up regulated proteins include: protein disulfide isomerases, proteins whose expression is negatively regulated by Hsp90 (e.g., Ndrg1), and proteins that maintain cellular integrity (e.g., Vimentin). In a verification phase, proteins identified in the protein profiling experiments and those inferred from Ingenuity Pathway Analysis were analyzed using Western blotting analysis on separate HOEC lysate samples, confirming many of the discovery findings. Additionally in HIV-infected patient samples Heat Shock Factor 1 is down regulated, which explains the reduced heat shock responses, while activation of the MAPK signal transduction cascade is observed. Overall, HAART therapy provides an incomplete immune recovery of the oral epithelial cells of the oral cavity for HIV-infected subjects, and the toxic side effects of HAART and/or HIV chronicity silence expression of multiple proteins that in healthy subjects function to provide robust innate immune responses and combat cellular stress.     

Human anti-V3 HIV-1 monoclonal antibodies encoded by the VH5-51/VL lambda genes define a conserved antigenic structure

Preferential usage of immunoglobulin (Ig) genes that encode antibodies (Abs) against various pathogens is rarely observed and the nature of their dominance is unclear in the context of stochastic recombination of Ig genes. The hypothesis that restricted usage of Ig genes predetermines the antibody specificity was tested in this study of 18 human anti-V3 monoclonal Abs (mAbs) generated from unrelated individuals infected with various subtypes of HIV-1, all of which preferentially used pairing of the VH5-51 and VL lambda genes. Crystallographic analysis of five VH5-51/VL lambda-encoded Fabs complexed with various V3 peptides revealed a common three dimensional (3D) shape of the antigen-binding sites primarily determined by the four complementarity determining regions (CDR) for the heavy (H) and light (L) chains: specifically, the H1, H2, L1 and L2 domains. The CDR H3 domain did not contribute to the shape of the binding pocket, as it had different lengths, sequences and conformations for each mAb. The same shape of the binding site was further confirmed by the identical backbone conformation exhibited by V3 peptides in complex with Fabs which fully adapted to the binding pocket and the same key contact residues, mainly germline-encoded in the heavy and light chains of five Fabs. Finally, the VH5-51 anti-V3 mAbs recognized an epitope with an identical 3D structure which is mimicked by a single mimotope recognized by the majority of VH5-51-derived mAbs but not by other V3 mAbs. These data suggest that the identification of preferentially used Ig genes by neutralizing mAbs may define conserved epitopes in the diverse virus envelopes. This will be useful information for designing vaccine immunogen inducing cross-neutralizing Abs.     

芋螺毒素SO3对大鼠海马神经元缺氧后胞内游离钙离子浓度的影响

目的:研究芋螺毒素SO3对培养大鼠海马神经元缺氧后胞内游离钙离子浓度的影响.方法:运用激光共聚焦显微镜(CLSM)测定缺氧后大鼠海马神经元胞内游离钙离子浓度的变化.结果与结论:芋螺毒素SO3可以明显抑制因缺氧所致原代培养大鼠海马神经元胞内游离钙离子浓度的上升.     

Comparative study of apoptosis-related gene loci in human, mouse and rat genomes

Many genes are involved in mammalian cell apoptosis pathway. These apoptosis genes often contain characteristic functional domains, and can be classified into at least 15 functional groups, according to previous reports. Using an integrated bioinformatics platform for motif or domain search from three public mammalian proteomes (International Protein Index database for human, mouse, and rat), we systematically cataloged all of the proteins involved in mammalian apoptosis pathway. By localizing those proteins onto the genomes, we obtained a gene locus centric apoptosis gene catalog for human, mouse and rat.Further phylogenetic analysis showed that most of the apoptosis related gene loci are conserved among these three mammals. Interestingly, about one-third of apoptosis gene loci form gene clusters on mammal chromosomes, and exist in the three species, which indicated that mammalian apoptosis gene orders are also conserved. In addition, some tandem duplicated gene loci were revealed by comparing gene loci clusters in the three species. All data produced in this work were stored in a relational database and may be viewed at http://pcas.cbi.pku.edu.cn/database/apd.php.     

TIGIT-Fc alleviates acute graft-versus-host disease by suppressing CTL activation via promoting the generation of immunoregulatory dendritic cells

Graft-versus-host disease (GVHD) is the most common complication and major limitation of allogeneic hematopoietic stem cell transplantation. The CD226/TIGIT-CD155 signal is critical for the cross-talk between T cells and dendritic cells (DCs). Studies have shown that blockade of the CD226-CD155 interaction, using an anti-CD226 antibody, can significantly ameliorate GVHD. It has also been reported that a TIGIT-Fc fusion protein exerts immunosuppressive effects by binding to CD155 on DCs. Here, we used a mouse allogeneic acute GVHD model to explore the therapeutic potential and mechanism of action of TIGIT-Fc. C57/BL6 and Balb/c mice were used as hematopoietic cell graft donors and recipients, respectively. In the TIGIT-Fc-treated mice, GVHD symptom occurrence and mortality were delayed compared to that in isotype control group mice. Histopathological analyses revealed that following TIGIT-Fc treatment, liver and small intestine tissue damage was reduced with minimal lymphocytic infiltration. The percentage of CD8⁺IFN-γ⁺ and CD8⁺ granzyme B⁺ cells significantly decreased in the TIGIT-Fc group. Moreover, treatment with TIGIT-Fc, even after the onset of GVHD, ameliorated symptoms and prolonged survival. TIGIT-Fc also inhibited CD8⁺ T cell activation in vitro; this was dependent on the presence of CD155 on bone marrow-derived dendritic cells (BMDCs) and on IL-10 production. In addition, TIGIT–CD155 ligation triggered both Erk phosphorylation and STAT3 nuclear translocation. These data indicate that TIGIT plays an important role in the development of GVHD and is an ideal molecular target to treat acute GVHD.     

Antibody drug conjugates of cleavable amino-alkyl and aryl maytansinoids

Natural products have been used for many medicinal purposes for centuries. Antibody drug conjugates (ADCs) have utilized this rich source of small molecule therapeutics to produce several clinically useful treatments. ADCs based on the natural product maytansine have been successful clinically. The authors further the utility of the anti-cancer natural product maytansine by developing efficacious payloads and linker-payloads for conjugating to antibodies. The success of our approach was realized in the EGFRvIII targeting ADC EGFRvIII-16. The ADC was able to regress tumors in 2 tumor models (U251/EGFRvIII and MMT/EGFRvIII). When compared to a positive control ADC, the efficacy observed was similar or improved while the isotype control ADCs had no effect.     

Novel benzodiazepines derivatives as analgesic modulating for Transient receptor potential vanilloid 1

A new series of derivatives of 3-(7-chloro-5-(2-fluorophenyl)-2-oxo-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)propanoic acid were designed and synthesized as analgesic modulating for Transient receptor potential vanilloid 1. They were investigated for TRPV1 antagonistic activity in vitro, analgesic activity and sedative activity in vivo and aqueous solubility. Preliminary studies identified 3-(7-chloro-5-(2-fluorophenyl)-2-oxo-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)-N,N-dimethylpropanamide(Compound 11), as a potent analgesic modulating for TRPV1 with potent activity and good aqueous solubility.