微囊藻细胞抽提液对小鼠血液的亚慢性毒性

本文研究了注射含微囊藻毒素的微囊藻细胞抽提掖对小鼠血液以及免疫系统的亚慢性毒性作用。实验分为3个处理组和1个对照组（每组10只昆明小鼠,雌雄各半）,采用腹腔注射的染毒方法对3个处理组进行暴露,剂量分别为2.4、4.8 和 9.6 μg microcystin-LR/kg body weigh,对照组注射等量的生理盐水,连续注射14d。实验结果表明,14d 染毒后,小鼠的肝体比和脾体比都明显增大（p < 0.05）, 同时在9.6 μg/kg处理组,血清丙氨酸转移酶、天冬氨酸转移酶、乳酸脱氢酶和碱性磷酸酶活性与对照相比明显升高,但血清总蛋白、白蛋白和白蛋白/球蛋白比率下降。这些指标的变化说明,含微囊藻毒素的微囊藻细胞提取液对处理组小鼠肝脏造成了损伤,肝组织学观察也印证了这个结果,在处理组小鼠肝组织有明显的水样变性。另外,9.6 μg/kg处理组小鼠血液白细胞数量比对照组明显减少。组织细胞学观察发现,处理组小鼠脾脏也有明显的损伤。该实验结果说明,含微囊藻毒素的微囊藻细胞抽提液对小鼠的血液和免役系统都产生了一定程度的损伤。     

一株耐低温纤维素酶高产菌株的筛选、鉴定和产酶的初步试验

从若尔盖高寒湿地距表层80cm处土壤中筛选出一株纤维素酶高产菌株XW-1。根据形态学、生理生化特征以及16SrDNA核酸序列分析结果表明,该菌属于缺陷短波单胞菌(Brevundimonas sp.)。对该菌产酶条件研究表明,XW-1在含0.5%CMC-Na条件下,20°C培养3d后出现最高酶活,达到15.6U/mL。对其酶学性质初步研究表明,该菌株所产纤维素酶的最适pH为6.0,最适反应温度为20°C,15°C时相对酶活达到80%,并且在5°C时,相对酶活仍能保持56%。     

Synthesis, crystal structure and magnetic properties of a one-dimensional Mn(III) Schiff-base complex bridged by derivative of tetracyano-p-quinodimethane

A new one-dimensional manganese(III) Schiff-base complex [Mn(III)(salophen) (MeOTCNQ)] · CH₃CN 1 (salophen = N,N′-bis(salicylidene)phenylenediamine) bridged by 7-methoxy-7,7,8,8-tetra-cyano-p-quinodimethane (MeOTCNQ), has been synthesized and characterized by X-ray crystallography and magnetic studies. Crystal structure study reveals that complex 1 has a 1D manganese(III) chain bridged by MeOTCNQ ligand which was obtained unexpectedly from tetracyano-p-quinodimethane (TCNQ) reacting with methanol. Noticeably, MeOTCNQ molecules in complex 1 adopt an unusual cis-syn coordination mode. The analysis of magnetic data indicates that a weak intrachain antiferromagnetic interaction exists in complex 1.     

Lactobacillus acidophilus LAP5 able to inhibit the Salmonella choleraesuis invasion to the human Caco-2 epithelial cell

The mechanisms for lactic acid bacteria (LAB) to inhibit Salmonella invasion appear to be multifactorial and include the adhesion of LAB to host intestine epithelium, the production of organic acids, or bacteriocin by LAB cells. Previously, we found a strain of Lactobacillus acidophilus isolated from swine, i.e. strain LAP5, was with antagonistic effect against Salmonella typhimurium. This strain LAP5 was also found to meet the requirements for probiotic use. In this study, we evaluate the potential of LAP5 strain to protect the human or swine from infection by Salmonella choleraesuis. We present evidence that the culture of LAP5 was able to inhibit the invasion of S. choleraesuis to human Caco-2 cell line. The LAP5 cell culture showed a higher inhibitory effect on the invasion of S. choleraesuis to Caco-2 cells than the spent culture supernatant (SCS) of LAP5 did. Also, the pH, organic acids or the bacteriocin, which act at low pH conditions, may play the role of antagonistic effect. The addition, adhesion of LAP5 cells to Caco-2 cell line may also play roles to reduce the invasion of S. choleraesuis.     

运输时间和密度对翘嘴鲌皮质醇、耗氧率及氧气袋内水质的影响

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Antagonistic activity of Lactobacillus acidophilus RY2 isolated from healthy infancy feces on the growth and adhesion characteristics of enteroaggregative Escherichia coli

Enteroaggregative Escherichia coli (EAggEC) infection is an important cause of acute diarrhea, affecting children in developing countries and travelers visiting tropical or subtropical areas. Three probiotics can exert bacteriostatic or bactericidal effects on human and animal intestinal pathogens, the efficiency of probiotics on EAggEC infection remains unclear. In this study, the antagonistic activity of probiotic bacteria isolated from infant faeces was examined against several EAggEC stains. While three isolates, Lactobacillus acidophilus RY2, Lactobacillus salivarius MM1 and Lactobacillus paracasei En4 were shown to significantly inhibit the growth of EAggEC. In addition, the antagonistic activity of the Lactobacillus species was maintained despite heating (100 °C, 15 min) of cell free culture supernatant (CFCS). The antagonistic activity of the CFCS however, could be reduced following lactate dehydrogenase treatment and at pH 7.2. Furthermore, in an adhesion–inhibition assay, L. acidophilus RY2 was shown to be more effective than L. salivarius MM1 and L. paracasei EN4. This study suggests that L. acidophilus RY2 could be used as a probiotic organism against EAggEC.     

母猪繁殖力性状影响因素分析及遗传参数估计

母猪繁殖力是影响种猪场经济效益的重要因素。文章对纯种大白猪、长白猪、杜洛克猪的8491窝产仔记录进行统计分析,建立固定效应模型对总产仔数、健仔数、初生窝重、弱仔数、死胎数、木乃伊胎数和畸形胎数共7个繁殖性状进行最小二乘分析,分析胎次、配种季节、品种对母猪繁殖性能的影响,同时比较了纯繁和杂交的效果。利用动物模型REML(约束最大似然)方法估计繁殖性状的遗传力和遗传相关。结果表明,胎次、配种季节和品种对总产仔数、健仔数、初生窝重影响极显著(P<0.001),胎次和品种对弱仔数影响极显著(P<0.001),但配种季节对弱仔数影响不显著。胎次对死胎数影响显著(P<0.05),而配种季节和品种对死胎数影响不显著,胎次、配种季节和品种对木乃伊胎、畸形胎数影响不显著。长白♂×大白♀交配组合具有最高的总产仔数、健仔数和初生窝重。繁殖性状遗传力估计结果显示,长白猪初生窝重的遗传力最高,为0.227。其余性状遗传力均在0.2以下,为低遗传力性状。3个品种母猪的健仔数与初生窝重、总产仔数与健仔数之间的遗传相关达0.96以上。研究结果为降低非传染性因素造成的种母猪产仔数低的问题以及种猪场对母猪繁殖力的选育提高提供了参考数据和理论依据。     

Evaluation of Lactic Acid Bacteria Isolated from Fermented Plant Products for Antagonistic Activity Against Urinary Tract Pathogen <Emphasis Type="Italic">Staphylococcus saprophyticus</Emphasis>

Urinary tract infections (UTIs) are the most common infectious diseases in infants and the elderly; they are also the most common among nosocomial infections. The treatment of UTIs usually involves a short-term course of antibiotics. The purpose of this study was to identify the strains of lactic acid bacteria (LAB) that can inhibit the urinary tract pathogen Staphylococcus saprophyticus, as alternatives to antibiotics. In this study, we collected 370 LAB strains from fermented plant products and reference strains from the Bioresources Collection and Research Center (BCRC). Using spent culture supernatants (SCS), we then screened these LAB strains with for antimicrobial effects on urinary tract pathogens by the well-diffusion assay. Seven LAB strains—PM2, PM68, PM78, PM201, PM206, PM229, and RY2—exhibited inhibitory activity and were evaluated for anti-growth activity against urinary tract pathogens by the co-culture inhibition assay. Anti-adhesion and anti-invasion activities against urinary tract pathogens were evaluated using the SV-HUC-1 urothelial cell cultures. The results revealed that the survival rate of S. saprophyticus ranged from 0.9–2.96%, with the pH continuously decreasing after co-culture with LAB strains for 4 h. In the competitive adhesion assay, the exclusion and competition groups performed better than the displacement group. In the SV-HUC-1 cell invasion assay, PM201, PM206, PM229, and RY2 were found to inhibit the invasion of SV-HUC-1 cells by S. saprophyticus BCRC 10786. To conclude, RY2, PM229, and PM68 strains exhibited inhibitory activity against the urinary tract pathogen S. saprophyticus.     

PPIM: A Protein-Protein Interaction Database for Maize

Maize (Zea mays) is one of the most important crops worldwide. To understand the biological processes underlying various traits of the crop (e.g. yield and response to stress), a detailed protein-protein interaction (PPI) network is highly demanded. Unfortunately, there are very few such PPIs available in the literature. Therefore, in this work, we present the Protein-Protein Interaction Database for Maize (PPIM), which covers 2,762,560 interactions among 14,000 proteins. The PPIM contains not only accurately predicted PPIs but also those molecular interactions collected from the literature. The database is freely available at http://comp-sysbio.org/ppim with a user-friendly powerful interface. We believe that the PPIM resource can help biologists better understand the maize crop.Maize (Zea mays) is one of the most important crops in the world. Understanding the molecular mechanisms underlying various traits of maize (e.g. response to drought and salt) is important to improve the quality and yield of the crop. Although the maize genome sequence has unraveled the gene components of the crop, most traits involve complex interactions among molecules. Some protein-protein interactions (PPIs) have been experimentally determined in maize. For example, the CENTRORADIALIS8 protein was found to interact with the floral activator DLF1 protein with yeast two-hybrid assays (Danilevskaya et al., 2008), and barren stalk1 was found to interact with barren inflorescence2 with pull-down assays (Skirpan et al., 2008). Unfortunately, unlike other model organisms, there are very few molecular interactions available for maize. Therefore, a comprehensive maize interactome map is highly demanded.Recently, with more information about maize available, it has become practical to investigate the interactions between maize molecules. For example, with accumulating gene expression data, a gene coexpression network has been built to identify gene modules that play important roles in conditions of interest. With this idea, Downs et al. (2013) constructed a gene coexpression network based on gene expression data from 50 maize tissues and identified some gene modules that are important for development. By comparing the maize and rice (Oryza sativa) coexpression networks, Ficklin and Feltus (2011) identified some conserved gene modules between the two species, indicating their essential roles in crops. With protein abundance and phosphorylation data in different maize tissues across seven developmental stages, Walley et al. (2013) built a protein coexpression network to present kinase-substrate relationships. The metabolic network MaizeCyc (Monaco et al., 2013), containing enzyme catalysts, proteins, and other metabolites, has also been constructed. Focusing on maize kernel development, the expression quantitative trait loci have been investigated with RNA sequencing data (Fu et al., 2013), and the gene regulations underlying endosperm cell differentiation have been identified (Zhan et al., 2015).Despite the above efforts to identify possible interactions between molecules, no comprehensive interactome is available for maize. Most current approaches construct gene coexpression networks; however, these only describe the associations between genes and cannot tell which genes have real interactions. Under these circumstances, we present a comprehensive Protein-Protein Interaction Database for Maize (PPIM), which provides both our predicted physical and functional interactions as well as molecular interactions collected from the literature and public databases. To our knowledge, the PPIM is the most comprehensive database for maize to date. The user-friendly powerful interface accompanying the database can help biologists better explore the database.