Peripheral and intracerebral T cell immune response in cats naturally infected with Borna disease virus.

Borna disease virus (BDV) is a neurotropic agent with capacity to cause encephalomyelitis in a wide range of animal species, including horses and cats. Recent studies also point to a link between BDV and human neuropsychiatric disorders. The pathogenesis of Borna disease (BD) has been proposed to be immune-mediated, mainly through the effects of cytotoxic T cells. We used flow cytometric analysis in order to characterize the peripheral and intracerebral T cell immune response in cats naturally infected with BDV. Our results show the presence of two different CD8+ cell populations (CD8+low and CD8+high) in the blood, spleen and brain of these cats. In the brain, CD8+low cells predominated over CD8+high cells. Since CD8+low cells have been suggested to represent a non-MHC-restricted T cell population, the recruitment of such cells to the brains of BDV-infected cats could possibly be of importance for the clearance of virus from neurones.     

农机需求下降“十大原因”深度分析

2010年1月-4月,国内农机行业度过了一个漫长的市场低迷期,没有再现2009年同期的繁荣景象,市场的冷清出乎许多人的意料.从终端市场统计回来的资料分析,截止4月底,大中轮拖国内行业实际销售约5200台,同比下降50%以上,社会库存与实销比约4:1;有收获机行业风向标之称的小麦联合收获机实销量仅有8000台左右;另外全喂入水稻收获机销量也只有2000台左右,而2009年同期小麦联合收获机销量已经达到了35000台,全喂入水稻联合收获机销售量13500台,两种产品实销量同比分别下降75%、80%,主销产品社会实销量下降幅度之大,令人震惊.面对急转直下的市场销售现状,需要我们认真思考,深入探究,寻找问题根源和解决办法.     

Genetic associations of teat cup attachment failures,incomplete milkings,and handling time in automatic milking systems with milkability,temperament, and udder conformation

Automatic milking systems (AMS) allow recording of alternative milkability measures. Our objectives were to estimate genetic parameters for teat cup attachment failures (AtF), incomplete milkings (IM), and handling time (HT), and their genetic correlations with box time (BT), udder traits and temperament. Teat coordinates were to measure udder conformation and teat placement. Genetic correlations were estimated between these traits and linear classification traits. Data on Swedish Holstein and Swedish Red cows in 19 AMS herds and 74 herds with conventional milking parlors were analyzed. HT and IM had low heritabilities, but that of AtF was 0.21–0.31. Genetic correlations between AtF and temperament were 0.44–0.71 (calm cows having low AtF). Short BT was weakly genetically associated with shallow udders with short and thin teats. High genetic correlations (0.91–0.98) were found between teat coordinate traits and linear classification traits. Thus, AMS records can be effectively used to select for improved milkability and temperament.     

Genetic Relations between Reproduction,Chick Weight and Maternal Egg Composition in a White Leghorn Line

Selection is a viable way to increase egg dry matter, an important trait for the egg processing industry, but simultaneously a change in the embryonic environment takes place. The main purpose of this study was to estimate genetic parameters for the percentage of fertile eggs of eggs set (FERT), percentage of eggs hatched of fertile eggs (HATCH), percentage of live chicks 2 weeks post-hatch of hatched eggs (SURV/h) and of fertile eggs (SURV), and their genetic correlations with egg weight, albumen weight, yolk weight, yolk proportion, albumen dry matter and mean chick weight in a White Leghorn selection line. Direct and maternal heritabilities were low for FERT, HATCH and SURV, and non-existent for SURV/h. All direct-direct genetic correlations between reproduction traits and egg composition traits were not significant. Maternal-direct genetic correlations between HATCH and egg weight, albumen weight, yolk weight, yolk proportion and albumen dry matter were - 0.22, - 0.30, 0.28, 0.52 and 0.26, respectively. Similar correlations were found between SURV and egg composition traits. No significant genetic relationship was found between chick weight and post-hatch survival. In conclusion, within the range of values for egg composition in this study, selection for an increased egg dry matter should not impair reproduction.     

对提升科研院所惠农服务能力的思考

科技惠农服务是推动科技创新和成果转化、支撑农业提质增效的有效载体。地方科研院立足现代农业发展特点,通过完善科技惠农服务管理体系、创新服务模式和机制,深化了科研与产业合作。根据都市型现代农业转型发展需求、科技惠农服务"四种功能"发挥和"三个服务"目标要求,该研究从强化科技惠农工作的统筹布局、深化产学研用合作、提升基地示范展示水平、深化科技培训和普及工作、推动科技协同服务等方面,继续提升科技惠农服务能力。     

新形势下北京种业发展的路径研究

掌握种业发展现状和科学判断发展形势是探索新型种业体系建立路径的重要内容。北京籽种产业具有基础性、战略性、知识性和辐射性等特点。促进北京种业壮大,对"种业之都"建设和保障国家粮食安全具有重要意义。该研究总结了"十二五"以来北京籽种产业发展取得成效及问题,在对现代农业、科技创新、市场环境等发展趋势进行判断基础上,从深化机制、优化环境、建设育种体系、推动产业化等方面提出北京种业发展的路径。     

Changes in stem taper for birch plants growing in tree shelters

Plantings with pendula (Betula pendula Roth) and pubescent (Betula pubescens Ehrh.) birches were studied on five localities (Lat. 57–60 ° N) in Sweden. Seedlings were planted in 1988 or 1989. The experiment contained 50 plants per parcel and five replications per treatment. Among treatments harrowed area and birches covered with tree shelter were included. In spring 1993 five plants growing on harrowed area, with and without tree shelter, respectively were randomly chosen on each parcel. A total of 25 birches per treatment, species and locality were used. The trial was replicated in 1994 and 1995. The plant height was estimated and diameter at 20 and 60% of tree height was measured each year for 4 yr. The stem taper was calculated by the quotient D₆₀/D₂₀. The stem taper for birches without tree shelter was 0.5 for both species on all localities. The quotients for birches, which have grown in tree shelter, were 0.6–0.75 the first years of the trial. Then the quotients decreased and 2–3 years later they were on the same level as for birches planted without tree shelters. The results of the studies indicate that tree shelters should be removed two to three years after the plant has reached the top of the shelter. The height of the tree shelter might be shortened to 0.8–1.0 m to stabilise the plant earlier than with the conventional shelter height of 1.2 m.     

Genetic and functional characterization of the NanA sialidase from Clostridium chauvoei

ABSTRACT: Clostridium chauvoei is the causative agent of blackleg, a wide spread serious infection of cattle and sheep with high mortality. In this study we have analyzed the sialidase activity of the NanA protein of C. chauvoei and cloned the sialidase gene nanA. Sialidase is encoded as a precursor protein of 722 amino acids with a 26 amino acid signal peptide. The mature sialidase has a calculated molecular mass of 81 kDa and contains the carbohydrate binding module 32 (CBM32, or F5/8 type C domain), the sialic acid binding module CBM40 and the enzymatically active sialidase domain found in all pro- and eukaryotic sialidases. Sialidase activity does not require the CBM32 domain. The NanA protein is secreted by C. chauvoei as a dimer. The nanA gene was found to be conserved and sialidase activity was found in C. chauvoei strains isolated over a period of 50 years from various geographical locations. Antiserum directed against a recombinant 40 kDa peptide containing CBM40 and part of the enzymatically active domain of NanA neutralized the secreted sialidase activity of all C. chauvoei strains tested.     

A nationwide outbreak of Salmonella bovismorbificans associated with sprouted alfalfa seeds in Finland, 2009

Salmonella enterica serotype Bovismorbificans is a rare serotype in Finland. In June 2009, a nationwide outbreak of S. Bovismorbificans infections occurred, and 42 clinical isolates were identified. We conducted a case-control study enrolling 28 cases and 48 matched controls, and found ready-to-eat alfalfa sprouts associated with the infection (odds ratio = 35.2, 95% confidence interval 2.8-435). The sprouts were traced back to a domestic producer, with the seeds originating in Italy. Although finding microbiological evidence for sprouts as a source of this outbreak was very challenging, S. Bovismorbificans was finally found in sprouts germinated in the laboratory, and in soaking and rinse waters during the germination process. The pulsed field gel electrophoresis showed that these isolates were identical to the human outbreak isolates. Before sampling, it is important to mix the seeds well and to take several large-size samples from different seed lots. Instead of analysing seeds, the analysis should be targeted to soaking or rinse water samples and to the sprouts germinated in a laboratory. Accordingly, the sprout producers should only buy seeds that have been analysed for Salmonella. The producers have to include Salmonella testing in their internal quality control to ensure that Salmonella is absent from sprouts placed on the market during their shelf-life. In order to reduce the health hazard caused by sprouts, an effective and safe decontamination procedure should also be developed for the seeds.     

精准扶贫下首都农业科技对口支援实践与思考

对口支援作为"精准扶贫"的重要措施,一直以来也是北京的重点工作之一。然而在当前扶贫开发的关键时期,受援地区农牧业发展水平仍较低,亟需提档升级。该研究选取北京对口支援的7个地区,开展实地调研,分析受援地区发展困境及需求,从工作机制及成效方面具体分析北京发挥科技优势开展对口援助的实践,并结合存在的问题,提出完善首都农业科技对口支援工作的几点思考。为对口支援工作及其他地区扶贫工作提供借鉴。