Characterization of humoral responses in mice immunized with plasmid DNAs encoding SARS-CoV spike gene fragments

The immunological characteristics of SARS-CoV spike protein were investigated by administering mice with plasmids encoding various S gene fragments. We showed that the secreting forms of S1, S2 subunits and the N-terminus of S1 subunit (residues 18-495) were capable of eliciting SARS-CoV specific antibodies and the region immediate to N-terminus of matured S1 protein contained an important immunogenic determinant for elicitation of SARS-CoV specific antibodies. In addition, mice immunized with plasmids encoding S1 fragment developed a Th1-mediated antibody isotype switching. Another interesting finding was that mouse antibodies elicited separately by plasmids encoding S1 and S2 subunits cooperatively neutralized SARS-CoV but neither the S1 nor S2 specific antibodies did, suggesting the possible role of both S1 and S2 subunits in host cell docking and entry. These results provide insights into understanding the immunological characteristics of spike protein and the development of subunit vaccines against SARS-CoV.     

Efficient mucosal vaccination mediated by the neonatal Fc receptor

Almost all infectious diseases are initiated at mucosal surfaces, yet intramuscular or subcutaneous vaccination usually provides only minimal protection at sites of infection owing to suboptimal activation of the mucosal immune system. The neonatal Fc receptor (FcRn) mediates the transport of IgG across polarized epithelial cells lining mucosal surfaces. We mimicked this process by fusing a model antigen, herpes simplex virus type-2 (HSV-2) glycoprotein gD, to an IgG Fc fragment. Intranasal immunization, together with the adjuvant CpG, completely protected wild-type, but not FcRn knockout, mice after intravaginal challenge with virulent HSV-2 186. This immunization strategy induced efficient mucosal and systemic antibody, B- and T-cell immune responses, with stable protection for at least 6 months after vaccination in most of the immunized animals. The FcRn-IgG transcellular transport pathway may provide a general delivery route for subunit vaccines against many mucosal pathogens.     

Soil respiration in Tibetan alpine grasslands: belowground biomass and soil moisture, but not soil temperature, best explain the large-scale patterns

The Tibetan Plateau is an essential area to study the potential feedback effects of soils to climate change due to the rapid rise in its air temperature in the past several decades and the large amounts of soil organic carbon (SOC) stocks, particularly in the permafrost. Yet it is one of the most under-investigated regions in soil respiration (Rs) studies. Here, Rs rates were measured at 42 sites in alpine grasslands (including alpine steppes and meadows) along a transect across the Tibetan Plateau during the peak growing season of 2006 and 2007 in order to test whether: (1) belowground biomass (BGB) is most closely related to spatial variation in Rs due to high root biomass density, and (2) soil temperature significantly influences spatial pattern of Rs owing to metabolic limitation from the low temperature in cold, high-altitude ecosystems. The average daily mean Rs of the alpine grasslands at peak growing season was 3.92 μmol CO(2) m(-2) s(-1), ranging from 0.39 to 12.88 μmol CO(2) m(-2) s(-1), with average daily mean Rs of 2.01 and 5.49 μmol CO(2) m(-2) s(-1) for steppes and meadows, respectively. By regression tree analysis, BGB, aboveground biomass (AGB), SOC, soil moisture (SM), and vegetation type were selected out of 15 variables examined, as the factors influencing large-scale variation in Rs. With a structural equation modelling approach, we found only BGB and SM had direct effects on Rs, while other factors indirectly affecting Rs through BGB or SM. Most (80%) of the variation in Rs could be attributed to the difference in BGB among sites. BGB and SM together accounted for the majority (82%) of spatial patterns of Rs. Our results only support the first hypothesis, suggesting that models incorporating BGB and SM can improve Rs estimation at regional scale.     

贵州六盘水发现东阳江麝鼩

在贵州省六盘水市杨梅乡慕尼克村,利用陷阱法捕捉到3号麝鼩属(Crocidura)标本。本次采集标本的体形较小,头体长(49.0 ± 0.8)mm,尾长[(41.8 ± 4.2)mm]略短于头体长(尾长/头体长为85%)。背毛呈浅灰褐色,腹毛颜色浅于背毛,呈灰色。尾部双色,背侧黑褐色,腹侧淡于背侧。前足背部白色,后足则为淡灰色。尾近乎裸露,尾基约1/3着生稀疏白色长毛。颅全长(15.92 ± 0.55)mm,脑颅高(4.75 ± 0.18)mm。上门齿1枚,有一长而大的前尖和一小而矮的后尖。上单尖齿3枚,第1单尖齿最大,第2单尖齿略大于第3单尖齿,1枚第四前臼齿(P4),3枚臼齿。上述特征与东阳江麝鼩(C. dongyangjiangensis)模式标本的描述和鉴定特征基本一致,因此将3号采集标本鉴定为东阳江麝鼩。基于Cyt b基因进行分子系统发育分析,采集标本与麝鼩属物种中的东阳江麝鼩遗传距离最近,在0.004 ~ 0.027之间。系统发生树显示,3号标本与东阳江麝鼩构成一个单系进化分支,进一步证实本次采集的3号标本是东阳江麝鼩,为贵州省分布新记录种。     

Association between cyclooxygenase-2 gene polymorphisms and risk of periodontitis: a meta-analysis involving 5653 individuals

There ?765G > C, ?1195G > A, and 8473T > C polymorphisms in cyclooxygenase-2 (COX-2) gene polymorphisms and periodontitis risk were investigated based on published studies; however, their results could not give a conclusive result. Hence, we performed this meta-analysis of six published studies with eight case–control studies including these three polymorphisms which searched from PubMed and Web of Science up to October 15th, 2013. Odds ratios (ORs) with corresponding 95 % confidence intervals (CIs) were calculated to evaluate the association between the three polymorphisms of COX-2 and periodontitis risk. The results from 2,580 periodontitis patients and 3,073 healthy controls showed that none of ?765G > C, ?1195G > A, or 8473T > C polymorphism was not associated with periodontitis susceptibility [Take ?765G > C for example: OR = 0.94, 95 % CI = (0.57–1.53) for C vs. G; OR = 2.34, 95 % CI = (0.72–7.62) for CC vs. GG; OR = 0.68, 95 % CI = (0.46–1.01) for CG vs. GG; OR = 0.81, 95 % CI = (0.52–1.27) for (CG+GG) vs. GG; OR = 2.57, 95 % CI = (0.80–8.29) for CC vs. (GG+CG)]. In subgroup analyses according to the type of periodontitis and ethnicity for ?765G > C and ?1195G > A, and deviations in Hardy–Weinberg equilibrium for ?765G > C, we only observe a boundary association between ?1195G > A polymorphism and Asian population. However, due to limitations of this meta-analysis, the results should treat with caution and we suggest the further researches should be carried out to verify our results.     

Anti-IL-33 antibody treatment inhibits airway inflammation in a murine model of allergic asthma

Interleukin (IL)-33 is a recently described member of the IL-1 family and has been shown to induce production of T helper type 2 cytokines. In this study, an anti-IL-33 antibody was evaluated against pulmonary inflammation in mice sensitized and challenged with ovalbumin. The anti-IL-33 or a control antibody (150 μg/mouse) was given intraperitoneally as five doses before the sensitization and antigen challenge. Treatment with anti-IL-33 significantly reduced serum IgE secretion, the numbers of eosinophils and lymphocytes, and concentrations of IL-4, IL-5, and IL-13 in bronchoalveolar lavage fluid compared with administration of a control antibody. Histological examination of lung tissue demonstrated that anti-IL-33 significantly inhibited allergen-induced lung eosinophilic inflammation and mucus hypersecretion. Our data demonstrate for the first time that anti-IL-33 antibody can prevent the development of asthma in a mouse model and indicate that blockade of IL-33 may be a new therapeutic strategy for allergic asthma.     

Examination of the quality of various force fields and solvation models for the equilibrium simulations of GA88 and GB88

Elucidating the relationship between sequence and conformation is essential for the understanding of functions of proteins. While sharing 88 % sequence identity and differing by only seven residues, GA88 and GB88 have completely different structures and serve as ideal systems for investigating the relationship between sequence and function. Benefiting from the continuous advancement of the computational ability of modern computers, molecular dynamics (MD) simulation is now playing an increasingly important role in the study of proteins. However, the reliability of MD simulations is limited by the accuracy of the force fields and solvent model approximations. In this work, several AMBER force fields (AMBER03, AMBER99SB, AMBER12SB, AMBER14SB, AMBER96) and solvent models (TIP3P, IGB5, IGB7, IGB8) have been employed in the simulations of GA88 and GB88. The statistical results from 19 simulations show that GA88 and GB88 both adopt more compact structures than the native structures. GB88 is more stable than GA88 regardless of the force fields and solvent models utilized. Most of the simulations overestimated the salt bridge interaction. The combination of AMBER14SB force field and IGB8 solvent model shows the best overall performance in the simulations of both GA88 and GB88. AMBER03 and AMBER12SB also yield reasonable results but only in the TIP3P explicit solvent model.