石粉与减水剂兼容性试验研究

为发挥石粉生态混凝土绿色环保的特点,在满足规范和成本要求的条件下,提高石粉的利用价值,以确定适用减水剂类别。通过在石粉砂浆中应用4种常用的减水剂,研究了其不同减水剂环境下石粉砂浆和凝结时间及抗压强度之间的关系。结果表明:石粉砂浆在不同减水剂环境中凝结时间及抗压强度没有明显区别,进一步为高掺量石粉生态混凝土的应用与发展提供参考。     

Ehrlichia canis in dogs of Mexico: Prevalence,incidence, co–infection and factors associated

Rickettsial infections in dogs of Mexico were investigated. A total of 246 dogs were blood sampled and initially screened to detect Ehrlichia canis, E. chaffeensis, E. ewingii, Anaplasma phagocytophilum and Rickettsia rickettsii by a quantitative real–time PCR (qPCR) assay. Sixty–five dogs were monitored and sampled twice 7–8 months apart. Using the qPCR, 72 positive dogs to E. canis were detected (prevalence of 29.26%). These dogs were also tested by nested PCR to detect the same pathogens. None of the studied dogs were positive to E. chaffeensis, E. ewingii, R. rickettsii nor A. phagocytophilum by both PCR assays. The cumulative incidence of E. canis infection was 38.46%. Sequencing analysis of the nested PCR products revealed 100% and 98.1% identity of E. canis and R. parkeri, respectively. We found a dog co–infected with E. canis and R. parkeri.     

益生菌防治畜禽细菌性肠炎作用机制的研究进展

益生菌是一类对宿主机体有益、安全无害的活微生物,代替抗生素和疫苗广泛用于畜禽细菌性肠炎的防治。益生菌主要通过与病原菌竞争黏附位点、分泌抑菌物质、加固肠道黏膜屏障、调节肠道免疫应答等抑制病原菌增殖,缓解肠道炎症,防治细菌性肠炎的发生。本文对益生菌的作用机制进行了详细阐述,为益生菌的研究和应用提供参考。     

优良观赏保健树大叶冬青扩繁利用研究

在引进大叶冬青树种种质资源的基础上,系统地研究了大叶冬青生物学特性、生态适应性、生长习性、实生种播苗关键技术和组织培养及其微繁技术,以及生态复合拟生栽培技术,培育出了大叶冬青绿化苗木18万株。并测定了大叶冬青叶内可溶性蛋白质、超氧化物歧化酶(SOD)等抗衰老成分含量和叶组织中抗菌成分含量及其抑菌功能。因地制宜研制出优质嫩芽型、嫩叶炒青型、老叶微波干燥型3种苦丁保健绿茶,为大叶冬青叶资源产业化开发奠定了基础。     

Kaurane-type diterpenoids from Chromoleana odorata, their X-ray diffraction studies and potent α-glucosidase inhibition of 16-kauren-19-oic acid

A new diterpenoid, 15-angeloyloxy-16,17-epoxy-19-kauronic acid (1), along with five known metabolites, 16-kauren-19-oic acid (2), 6′-hydroxy-2′,3′,4,4′-tetramethoxychalcone (3), isosakuranetin (4), acacetin (5), and kaempferide (6) was isolated from the organic extracts of the roots of Chromoleana odorata. Their structures were determined by spectroscopic evidences. The structures of 1 and 2 were further confirmed by single-crystal X-ray diffraction studies. Compound 2 exhibited significant α-glucosidase inhibitory and antibacterial activities against Escherichia coli and Bacillus subtilis.     

Bioactive plants from Argentina and Bolivia

Antibacterial and molluscicidal activities of methanol and chloroform extracts of 16 plant species belonging to the families Compositae and Melastomataceae were evaluated. The chloroform extract of Vernonanthura tweediana and the methanol extract of Senecio santelisis resulted to be very toxic to brine shrimp nauplii (LC(50)=1 microg/ml). Chloroform extracts of S. santelisis and Senecio leucostachys as well as the methanol extract of Wedelia subvaginata displayed molluscicidal effects on Biomphalaria peregrina showing LC(100)<100 microg/ml. Moderate antibacterial action was produced by the chloroform extracts of Flaveria bidentis, Grindelia scorzonerifolia and Vernonia incana against two strains of Staphylococcus aureus.     

不同药剂浸泡处理对山桃稠李种子发芽的影响

为了促进山桃稠李种子萌发,提高山桃稠李种子繁殖的发芽率,以清水作为对照,采用不同浓度的高锰酸钾、过氧化氢、赤霉素对山桃稠李种子进行处理,比较不同药剂、不同浓度及不同处理时间对山桃稠李种子发芽的影响。结果表明:不同药剂处理的种子发芽率有显著差异,不同处理时间之间没有显著差异,各药剂处理按照发芽率由高到低的顺序排列依次为高锰酸钾、赤霉素、过氧化氢、水处理。对发芽促进效果最佳的组合是0.7%的高锰酸钾浸泡处理48h,发芽率可达88%。     

Infectious agent detections in archived Sockeye salmon (Oncorhynchus nerka) samples from British Columbia,Canada (1985–94)

In response to concerns that novel infectious agents were introduced through the movement of eggs as Atlantic salmon aquaculture developed in British Columbia (BC), Canada, we estimated the prevalence of infectious agents in archived return‐migrating Sockeye salmon, from before and during aquaculture expansion in BC (1985–94). Of 45 infectious agents assessed through molecular assays in 652 samples, 23 (7 bacterial, 2 viral and 14 parasitic) were detected in liver tissue from six regions in BC. Prevalence ranged from 0.005 to 0.83 and varied significantly by region and year. Agent diversity ranged from 0 to 12 per fish (median 4), with the lowest diversity observed in fish from the Trans‐Boundary and Central Coast regions. Agents known to be endemic in Sockeye salmon in BC, including Flavobacterium psychrophilum, Infectious haematopoietic necrosis virus, Ceratonova shasta and Parvicapsula minibicornis, were commonly observed. Others, such as Kudoa thyrsites and Piscirikettsia salmonis, were also detected. Surprisingly, infectious agents described only recently in BC salmon, Ca. Branchiomonas cysticola, Parvicapsula pseudobranchicola and Paranucleospora theridion, were also detected, indicating their potential presence prior to the expansion of the aquaculture industry. In general, our data suggest that agent distributions may not have substantially changed because of the salmon aquaculture industry.     

三种豆科牧草愈伤组织继代培养中抗褐化的研究

为解决3 种豆科牧草愈伤组织继代培养中的褐化问题，以‘新牧4 号’紫花苜蓿、普通红豆草和‘海法’三叶草愈伤组织为材料，探讨不同防褐化措施在3 种豆科牧草愈伤继代培养过程中抗褐化效果的影响。结果表明，在苜蓿和红豆草愈伤组织的继代培养中，对愈伤组织褐化抑制效果较好的是AgNO3，浓度为0.02 g/L 时，褐化率分别为13%、15%，愈伤组织褐化程度强弱依次是PVP＞柠檬酸＞AgNO3；在三叶草愈伤组织的继代培养中，对愈伤组织褐化抑制效果较好的是AgNO3，浓度为0.015 g/L时，褐化率为32%，愈伤组织褐化程度强弱依次是柠檬酸＞PVP＞AgNO3。一定浓度的AgNO3不仅能有效控制褐化，还在一定程度上促进了愈伤组织的生长。