Adherence of Actinobacillus pleuropneumoniae serotype 1 to swine buccal epithelial cells involves fibronectin

The swine pathogen Actinobacillus pleuropneumoniae serotype 1 was investigated for its ability to adhere to swine, rat, and human buccal epithelial cells (BEC). The highest number of bacteria adhered was to swine BEC. This binding ability was affected by heating, extreme pH, treatment with sodium dodecyl sulfate, ethylenediamine tetraacetate, or periodate, and proteolysis, suggesting that cell-surface glycoproteins participate in adherence and that adherence is based mostly on ionic interactions. Mannose and swine fibronectin may play a direct role in this interaction. Convalescent-phase serum from naturally infected pigs inhibited the adhesion. There was a correlation between bacterial pathogenicity as well as host specificity and the capacity for adherence to swine BEC. Adhesion to swine BEC provides a convenient method to study in vitro the adherence of A. pleuropneumoniae and other pathogens of the pig respiratory tract.     

银翘复方药渣发酵处理试栽毛头鬼伞及主要药物成分分析

为回收利用生产银翘片废弃药渣,以毛头鬼伞为供试菌株,发酵处理银翘药渣;建堆配料设计原则为控制总料C/N接近40∶1,以玉米芯为主料(配合添加奶牛粪、尿素),逐渐增大银翘药渣用量,以替代玉米芯;堆料共采用4个配方,配方A(CK):玉米芯200kg,牛粪100kg,尿素3.5kg,辅料6%(生石灰2%、石膏2%、过磷酸钙2%);配方B:玉米芯100kg,银翘药渣50kg,牛粪50kg,尿素1.0kg,辅料6%;配方C:玉米芯75kg,银翘药渣100kg,牛粪50kg,辅料6%;配方D:玉米芯50kg,银翘药渣150kg,牛粪50kg,辅料6%。4个配方堆料总干质量均在200kg以上,依墙建堆成半圆锥形(h≥1.0m,r≥1.4m);发酵升温14d(4-3-3-2-2)、经4次翻堆后,摊料降温装袋接种,待菌丝满袋后脱袋覆土出菇。结果表明:以配方C的产出率为最高,其相应生产指标为,初始C/N为41.66、终点C/N为23.71、腐熟度T为0.569、接种满袋率93.7%、菌袋平均产量381.9g·kg~(-1)、生物学效率41.0%。经HPLC检测,配方C发酵料中绿原酸、牛蒡苷含量分别为5.20~5.40、4.49~5.30μg·g~(-1),其栽培所得子实体中绿原酸、牛蒡苷含量分别为0.40~0.45、3.81~4.27μg·g~(-1),其中牛蒡苷从栽培料到子实体的迁移率达84.93%。     

园林植物春季最佳观赏期调查研究

目前,由于缺乏准确的园林植物最佳观赏期的资料,导致优秀的规划设计方案难以落到实处,园林景点建成之后景观效果大打折扣。针对以上问题,作者采用实地调查观测的方法对园林植物春季最佳观赏期和最佳观赏顺序进行了研究。记录整理典型地点园林植物的最佳观赏期和最佳观赏顺序,为园林规划设计、植物配置和养护管理提供科学的参考依据。     

保定地区几个早熟苹果品种(系)生长观察

为筛选适宜保定地区栽植的早熟苹果品种,以嫁接在SH40中间砧上的不同早熟苹果品种(系)为试材,测定了不同品种(系)早熟苹果树体生长发育指标和果实品质。结果表明:除嘎啦早熟变异外,其他供试品种(系)树体生长较好,3年生时Xu2-7、Xu3-2树高330.0~352.5 cm,4年生时为394.0~417.5 cm,Xu3-2、藤牧1号、信浓红4年生为336.5~381.0 cm。4年生时,干径以Xu2-5最大;短枝、中枝、叶丛枝均以Xu2-5最多,长枝以Xu2-7最多,总枝量以Xu2-5最多;藤牧1号短枝所占比例最高(57.4%)。应用模糊综合评判法得出Xu2-5、Xu2-7、信浓红、藤牧1号果实品质较高。     

玉米青贮与花生秧配比对奶牛瘤胃中花生秧降解特性的影响

本试验旨在研究玉米青贮与花生秧配比对奶牛瘤胃中花生秧降解特性的影响。选择4头体重、生理状态、生产性能相近,装有永久瘤胃瘘管的中国荷斯坦奶牛,分别饲喂含有玉米青贮与花生秧不同配比的全混合日粮(TMR),3种TMR中玉米青贮与花生秧的干物质(DM)配比分别为3.9∶1.0(A组)、1.2∶1.0(B组)、0.4∶1.0(C组)。试验分3期进行,依次进行A、B、C组试验。每期预试15 d,采样期4 d;共57 d。采用尼龙袋瘤胃降解技术测定花生秧在奶牛瘤胃中DM、粗蛋白质(CP)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)的72 h瘤胃降解率,并求得目标养分的动态降解参数及有效降解率。结果表明:1)花生秧的DM在瘤胃中有效降解率为56.49%~59.62%,CP为40.45%~47.36%,NDF为33.26%~35.20%,ADF为36.31%~37.45%。2)B组DM的有效降解率显著高于C组(P0.05),极显著高于A组(P0.01);B、C组的CP有效降解率显著高于A组(P0.05)。3)B、C组的NDF快速降解部分含量显著高于A组(P0.05);3种TMR对花生秧粗NDF和ADF有效降解率无显著影响(P0.05)。由此可见,花生秧具有较高的饲用价值。本试验条件下,玉米青贮与花生秧DM配比为1.2∶1.0时,可有效提高花生秧DM和CP的瘤胃降解率。     

产前和产后香味剂印迹训练对仔猪断奶后采食偏好的影响及其机理

仔猪断奶后受到心理、营养、环境等多方面的刺激,导致应激反应,影响仔猪的采食量。固体饲粮代替母乳是最大的应激源,通过在母猪饲粮中添加香味剂对仔猪产前和产后进行香味剂印迹训练,使仔猪逐渐喜欢这种气味,降低其对添加相同香味剂饲粮的应激反应,并对有相同气味的饲粮有采食偏好,从而提高仔猪的采食量。本文对产前和产后香味剂印迹训练对仔猪断奶后采食偏好的影响及其机理进行综述,为养猪业相关试验研究提供理论依据。     

Phylogenetic characterization of rabies virus isolates from Carnivora in Brazil

The incidence of canine rabies has been widely reported in Brazil, and new rabies virus (RV) variants, genetically similar to canine RV, have recently been isolated from foxes. In order to derive the epidemiological characteristics of Brazilian Carnivora RV, Brazilian RVs isolated from dogs, cats, and foxes were genetically analyzed. Brazilian Carnivora RV isolates were divided into 2 main lineages. The predominant lineage was found in dogs and cats, which included the Argentinean and Bolivian Carnivora RV isolates, and was extensively distributed throughout Brazil and surrounding countries. The other lineage consisted of three sublineages containing Brazilian dog and fox RV isolates, with the dog sublineages located on an internal branch of 2 fox sublineages, suggesting that RV transmission events might have occurred between foxes and dogs in the past. These results suggest that contact between dogs and wildlife has the potential to generate new rabies variants and that it is important to control RV infection cycles in both dogs and wildlife to prevent spread of rabies infection.     

贮藏时间与蒙药黄芩对紫花苜蓿草颗粒维生素和化学成分的影响

为有效保全苜蓿草颗粒贮藏过程中维生素及营养品质,本研究以紫花苜蓿草颗粒为研究材料,研究贮藏时间(0,60,120,180,240 d,冷冻240 d)与蒙药黄芩(0%,0.5%,1.0%,1.5%)对其维生素含量和营养品质的影响。结果表明：在贮藏过程中,与其他添加量相比,添加1.5%黄芩有利于保存苜蓿草颗粒维生素B5、维生素C和α-维生素E含量。贮藏60 d及以上显著降低了苜蓿草颗粒维生素B1、维生素B3、维生素C和维生素E含量;贮藏120 d时苜蓿草颗粒DM含量趋于稳定;苜蓿草颗粒贮藏180 d后其CP含量显著降低;贮藏0～180 d期间,随着贮藏时间的延长,苜蓿草颗粒NDF和ADF含量显著升高。与常温贮藏240 d相比,冷冻贮藏相同时间有利于保存苜蓿草颗粒中维生素B1、维生素B5、α-维生素E和OM含量,显著降低DM、NDF和ADF含量。因此,1.5%黄芩添加剂有利于保存苜蓿草颗粒维生素含量,且常温贮藏时间不宜超过60天。     

Comparison of water status indicators for young peach trees

We measured a series of physiological and physical indicators and compared them to xylem sap flow, to identify the most sensitive and reliable plant water status indicator. In the growing season of 1998, 4-year-old peach trees (Prunus persica Batsch cv. 'Suncrest', grafted on 'GF 677' rootstock) were studied under two irrigation treatments, 25 l day^у and no irrigation, and during recovery. Trials were conducted near Pisa (Italy) in a peach orchard situated on a medium clay loam soil and equipped with a drip-irrigation system (four 4 l h^у drippers per tree). Measurements of leaf water potential (ƒ_W), stem water potential (ƒ_S), and leaf temperature (T_l) were taken over 5 days (from dawn to sunset) and analyzed in conjunction with climatic data, sap flow (SF), trunk diameter fluctuation (TDF) and soil water content (SWC). Physiological indicators showed substantial differences in sensitivity. The first indication of changes in water status was the decrease of stem radial growth. TDF and SF revealed significant differences between the two irrigation treatments even in the absence of differences in pre-dawn leaf water potential (pdƒ_W), up until now widely accepted as the benchmark of water status indicators. Irrigated trees showed a typical trend in SF rate during the day, while in non-irrigated plants the maximum peak of transpiration was anticipated. Measurements of water potential showed ƒ_S to be a better indicator of tree water status than ƒ_W. T_l was found to have poor sensitivity. In conclusion, we found the sensitivity of the indicators from the most to the least was: TDF >SF rate >SF cumulated = pdƒ_W=ƒ_S>mdƒ_W>T_l.     

Controlled water table management as a strategy for reducing salt loads from subsurface drainage under perennial agriculture in semi-arid Australia

Recent community based actions to ensure the sustainability of irrigation and protection of associated ecosystems in the Murrumbidgee Irrigation Area (MIA) of Australia has seen the implementation of a regional Land and Water Management Plan. This aims to improve land and water management within the irrigation area and minimise downstream impacts associated with irrigation. One of the plan objectives is to decrease current salt loads generated from subsurface drainage in perennial horticulture within the area from 20 000 tonnes/year to 17 000 tonnes/year. In order to meet such objectives Controlled Water table Management (CWM) is being investigated as a possible ‘Best Management Practice’, to reduce drainage volumes and salt loads.During 2000–2002 a trial was conducted on a 15 ha subsurface drained vineyard. This compared a traditional unmanaged subsurface drainage system with a controlled drainage system utilizing weirs to maintain water tables and changes in irrigation scheduling to maximize the potential crop use of a shallow water table. Drainage volumes, salt loads and water table elevations throughout the field were monitored to investigate the effects of controlled drainage on drain flows and salt loads.Results from the experiment showed that controlled drainage significantly reduced drainage volumes and salt loads compared to unmanaged systems. However, there were marked increases in soil salinity which will need to be carefully monitored and managed.