鼠李糖乳杆菌LV108及其发酵乳免疫调节作用的比较

目的探讨鼠李糖乳杆菌LV108及其发酵乳对免疫抑制小鼠免疫功能的调节作用。方法将BALB/c小鼠随机分为5组,每组10只,即空白组(正常小鼠)、模型组(免疫抑制小鼠)、药物组(免疫抑制小鼠食物中添加左旋咪唑)、LV108菌悬液组(免疫抑制小鼠食物中添加LV108菌悬液)和LV108发酵乳组(免疫抑制小鼠食物中添加LV108发酵乳),除空白组外其余组构建免疫抑制小鼠模型。干预4周后,分别测定各组小鼠体质量和脏器指数,血清中白细胞介素2(IL2)、肿瘤坏死因子α(TNFα)和免疫球蛋白G(IgG)含量,血清溶血素含量、耳肿胀度和肝、脾巨噬细胞吞噬能力。结果相比模型组,LV108菌悬液组和LV108发酵乳组小鼠体质量增长速度、脏器指数、血清IL2与IgG水平、血清溶血值、耳肿胀度和巨噬细胞吞噬能力显著升高(均P<0.05);在脾脏指数、血清IL2与TNFα水平、血清溶血素含量和耳肿胀度免疫指标上,LV108菌悬液组与LV108发酵乳组之间比较差异具有统计学意义(均P<0.05)。结论LV108菌体及发酵乳对免疫抑制小鼠具备较全面的免疫调节作用,均可提高小鼠的自身免疫力;LV108发酵乳对小鼠的免疫调节作用强于LV108菌体。     

Prevalence of Exclusive Breastfeeding Practices and associated factors among mothers in Bahir Dar city,Northwest Ethiopia: a community based cross-sectional study

Background

Breastfeeding is an unequalled way of providing ideal food for the healthy growth and development of infants. World Health Organization (WHO) recommend exclusive breastfeeding (EBF) for six months which has a great contribution in reducing under five mortality, which otherwise leads to death of 88/1000 live birth yearly in Ethiopia. Hence, this study aimed to assess prevalence of EBF and associated factors in mothers in the city of Bahir Dar, Northwest Ethiopia.

Methods

A community-based cross-sectional study was conducted from 10 to 25 June 2012 among mothers who delivered 12 months earlier in Bahir Dar city, Northwest Ethiopia. A cluster sampling technique was used to select a sample of 819 participants. Data were collected using a structured and pre-tested questionnaire by face-to-face interview technique. Bivariate and multivariate analyses were performed to check associations and control confounding.

Results

Of 819 mother-infant pairs sampled, the overall age appropriate rate of EBF practice was found to be 50.3%. Having a young infant aged 0-1 month (AOR = 3.77, 95% CI = 1.54, 9.24) and 2-3 months (AOR = 2.80, 95% CI = 1.71, 4.58), being a housewife (AOR = 2.16, 95% CI = 1.48, 3.16), having prenatal EBF plan (AOR = 3.75, 95% CI = 2.21, 6.37), delivering at a health facility (AOR = 3.02, 95% CI = 1.55, 5.89), giving birth vaginally (AOR = 2.33, 95% CI = 1.40, 3.87) and receiving infant feeding counseling/advice (AOR = 5.20, 95% CI = 2.13, 12.68) were found to be significantly associated with EBF practice.

Conclusion

Prevalence of exclusive breastfeeding was low in Bahir Dar. Strengthening infant feeding advice/counseling both at the community and institutional levels, promoting institutional delivery, providing adequate pain relief and early assistance for mothers who gave birth by caesarean section, and enabling every mother a prenatal EBF plan during antenatal care were recommended in order to increase the proportion of women practicing EBF.

     

Regulator of G protein signaling Z1 (RGSZ1) interacts with Galpha i subunits and regulates Galpha i-mediated cell signaling

Regulator of G protein signaling (RGS) proteins constitute a family of over 20 proteins that negatively regulate heterotrimeric G protein-coupled receptor signaling pathways by enhancing endogenous GTPase activities of G protein alpha subunits. RGSZ1, one of the RGS proteins specifically localized to the brain, has been cloned previously and described as a selective GTPase accelerating protein for Galpha(z) subunit. Here, we employed several methods to provide new evidence that RGSZ1 interacts not only with Galpha(z,) but also with Galpha(i), as supported by in vitro binding assays and functional studies. Using glutathione S-transferase fusion protein pull-down assays, glutathione S-transferase-RGSZ1 protein was shown to bind (35)S-labeled Galpha(i1) protein in an AlF(4)(-)dependent manner. The interaction between RGSZ1 and Galpha(i) was confirmed further by co-immunoprecipitation studies and yeast two-hybrid experiments using a quantitative luciferase reporter gene. Extending these observations to functional studies, RGSZ1 accelerated endogenous GTPase activity of Galpha(i1) in single-turnover GTPase assays. Human RGSZ1 functionally regulated GPA1 (a yeast Galpha(i)-like protein)-mediated yeast pheromone response when expressed in a SST2 (yeast RGS protein) knockout strain. In PC12 cells, transfected RGSZ1 blocked mitogen-activated protein kinase activity induced by UK14304, an alpha(2)-adrenergic receptor agonist. Furthermore, RGSZ1 attenuated D2 dopamine receptor agonist-induced serum response element reporter gene activity in Chinese hamster ovary cells. In summary, these data suggest that RGSZ1 serves as a GTPase accelerating protein for Galpha(i) and regulates Galpha(i)-mediated signaling, thus expanding the potential role of RGSZ1 in G protein-mediated cellular activities.     

NMR structure of free RGS4 reveals an induced conformational change upon binding Galpha

Heterotrimeric guanine nucleotide-binding proteins (G-proteins) are transducers in many cellular transmembrane signaling systems where regulators of G-protein signaling (RGS) act as attenuators of the G-protein signal cascade by binding to the Galpha subunit of G-proteins (G(i)(alpha)(1)) and increasing the rate of GTP hydrolysis. The high-resolution solution structure of free RGS4 has been determined using two-dimensional and three-dimensional heteronuclear NMR spectroscopy. A total of 30 structures were calculated by means of hybrid distance geometry-simulated annealing using a total of 2871 experimental NMR restraints. The atomic rms distribution about the mean coordinate positions for residues 5-134 for the 30 structures is 0.47 +/- 0.05 A for the backbone atoms, 0. 86 +/- 0.05 A for all atoms, and 0.56 +/- 0.04 A for all atoms excluding disordered side chains. The NMR solution structure of free RGS4 suggests a significant conformational change upon binding G(i)(alpha)(1) as evident by the backbone atomic rms difference of 1. 94 A between the free and bound forms of RGS4. The underlying cause of this structural change is a perturbation in the secondary structure elements in the vicinity of the G(i)(alpha)(1) binding site. A kink in the helix between residues K116-Y119 is more pronounced in the RGS4-G(i)(alpha)(1) X-ray structure relative to the free RGS4 NMR structure, resulting in a reorganization of the packing of the N-terminal and C-terminal helices. The presence of the helical disruption in the RGS4-G(i)(alpha)(1) X-ray structure allows for the formation of a hydrogen-bonding network within the binding pocket for G(i)(alpha)(1) on RGS4, where RGS4 residues D117, S118, and R121 interact with residue T182 from G(i)(alpha)(1). The binding pocket for G(i)(alpha)(1) on RGS4 is larger and more accessible in the free RGS4 NMR structure and does not present the preformed binding site observed in the RGS4-G(i)(alpha)(1) X-ray structure. This observation implies that the successful complex formation between RGS4 and G(i)(alpha)(1) is dependent on both the formation of the bound RGS4 conformation and the proper orientation of T182 from G(i)(alpha)(1). The observed changes for the free RGS4 NMR structure suggest a mechanism for its selectivity for the Galpha-GTP-Mg(2+) complex and a means to facilitate the GTPase cycle.     

中国环境管理分区:方法与方案

我国生态环境可持续性及其影响因素的区域差异显著,各地区环境管理面临的主要挑战和需要优先解决的生态环境问题不同。进行环境管理分区,根据各地区生态环境特征及其影响因素的差异性,制定有针对性的环境管理政策,将有效促进我国区域生态环境的整体优化。采取定性和定量分析相结合的方法进行我国环境管理分区。首先,在我国3大自然区的基础上,根据我国的自然地理格局和已有的相关区划成果,把我国划分为4个环境管理大区,包括:南部季风区、北部季风区、西北干旱区和青藏高寒区。其次,通过建立的包含13个指标的环境管理分区指标体系,采用一维化欧式距离法分析各环境管理大区下相邻省级行政区环境特征的相似性,把环境特征相似性大的相邻地区划分到同一分区,得到以省级行政区为基本单元的我国环境管理分区方案。然后,结合地区间历史渊源和区域未来发展趋势分析,对基于相似性分析的初步分区方案进行调整,把我国划分为8个以省级行政区为基本单元环境管理区。最后,根据相关调整原则和方法,对以省级行政区为基本单元的分区方案的边界线进行调整,得到以地级行政区为基本单元的分区方案,把我国划分为东北地区、华北平原区、华北山地与高原区、东南沿海地区、长江流域中游地区、西南地区、西北干旱区和青藏高寒区8个环境管理区。     

Slaughterhouse wastewater treatment by combined chemical coagulation and electrocoagulation process

Slaughterhouse wastewater contains various and high amounts of organic matter (e.g., proteins, blood, fat and lard). In order to produce an effluent suitable for stream discharge, chemical coagulation and electrocoagulation techniques have been particularly explored at the laboratory pilot scale for organic compounds removal from slaughterhouse effluent. The purpose of this work was to investigate the feasibility of treating cattle-slaughterhouse wastewater by combined chemical coagulation and electrocoagulation process to achieve the required standards. The influence of the operating variables such as coagulant dose, electrical potential and reaction time on the removal efficiencies of major pollutants was determined. The rate of removal of pollutants linearly increased with increasing doses of PACl and applied voltage. COD and BOD(5) removal of more than 99% was obtained by adding 100 mg/L PACl and applied voltage 40 V. The experiments demonstrated the effectiveness of chemical and electrochemical techniques for the treatment of slaughterhouse wastewaters. Consequently, combined processes are inferred to be superior to electrocoagulation alone for the removal of both organic and inorganic compounds from cattle-slaughterhouse wastewater.