中国1923-1995年育成的651个大豆品种的遗传基础

从1923～1995年中国651个大豆育成品种(包括东北330个、黄淮海210个、南方111个)的系谱归纳出348个祖先亲本,将育成品种归属为348个细胞核家族和214个细胞质家族.全国每个育成品种实际使用的祖先亲本数由1960年前的平均1.59个增至1991～1995年的平均6.39个,总平均3.79个祖先亲本.从一个地区的祖先亲本总数着眼,东北、黄淮海、南方平均每个育成品种拥有的细胞核和细胞质祖先亲本数分别是0.50个和O.25个、0.71个和0.40个、0.97个和0.54个.祖先亲本的遗传贡献并不平衡,各区均有少数祖先亲本在育成品种中占很大遗传份额,东北地区尤为突出.黑龙江、山东、吉林、江苏等省大豆育成品种的细胞质来源均较为简单.     

肉鸡屠宰加工过程中沙门菌污染定量风险评估

为了构建肉鸡屠宰加工过程中沙门菌污染定量风险评估模型,分析鸡肉中沙门菌的消长变化规律,明确关键风险防控点,采用2015年部分肉鸡屠宰场沙门菌污染监测和调研数据,构建以烫煺后为评估过程起点,包括净膛、清洗预冷和分割传送的模块化过程风险评估模型,以不同分布描述各变量,并通过@RISK软件模拟运行。结果显示,通过构建的模型模拟屠宰加工后终端鸡肉产品中的沙门菌污染量,90%的可能分布在0~9MPN之间,而依据实际监测数据换算为5.3 MPN,说明模型可信。根据过程中各环节的模拟数据,分析了肉鸡携带的沙门菌消长变化,发现预冷后沙门菌污染总量明显下降,但分割传送后污染总量又有所回升。通过拟合的相关系数分析,明确了传送带上的沙门菌是影响终端鸡肉沙门菌污染的最关键风险点。本研究构建的肉鸡屠宰加工全过程沙门菌定量风险评估模型,可为肉鸡屠宰场沙门菌污染的卫生监管和风险管理提供理论依据。     

Gap disturbances and regeneration patterns in a Bosnian old-growth forest: a multispectral remote sensing and ground-based approach

Objectives

We examined canopy gap structure and regeneration patterns at the landscape scale using a combination of remote sensing and field-based surveys.

Methods

The study was carried out in the forest reserve of Lom, an old-growth Fagus-Abies-Picea forest located within the Dinaric Alps in the north-western part of Bosnia and Herzegovina. A high-resolution (1-m panchromatic and 4-m multispectral) Kompsat-2 satellite image was orthorectified and classified through an unsupervised pixel-based classification using an artificial neural network method.

Results

This approach allowed the identification of 650 canopy gaps, ranging in size from 32 to 1,776?m². Only 20 intermediate to large gaps (>250?m²) were identified, and they were mainly present near the perimeter of the reserve. The origin of these large openings was associated with past human-caused disturbances or topographic conditions. The species composition of regeneration within large, human-caused gaps differed markedly from small gaps and non-gap sites in the core area of the reserve. Shade-intolerant species dominated the seedling and sapling layers in large openings. The landscape approach employed in this study confirmed the hypothesis that small gaps predominate at Lom, especially within the core area of the reserve.     

Experimental study of pathogenicity of Pasteurella multocida serogroup F in rabbits

The role of Pasteurella multocida serogroup F in inducing disease in rabbits was investigated in this study. Three groups of 12 Pasteurella-free rabbits each were intranasally (i.n.), subcutaneously (s.c.), and perorally (p.o.) challenged, respectively. Six rabbits of each group were immunosuppressed using dexamethasone. Eight rabbits (four of them immunosuppressed) inoculated i.n. showed symptoms of respiratory distress resulting in respiratory failure and died or were euthanized in the terminal stage of the disease 3-6 days post-infection (p.i.). The main pathological findings were fibrinopurulent pleuropneumonia (immunocompetent rabbits) or diffuse haemorrhagic pneumonia (immunosuppressed rabbits). Septicemic syndrome ending with shock occurred in 11 rabbits (6 of them immunosuppressed) inoculated s.c., which died or were euthanized in the terminal stage of the disease 2-3 days p.i. The most significant pathological findings were extensive cutaneous and subcutaneous lesions. All of the p.o. inoculated rabbits survived the challenge showing no clinical signs of the disease and no macroscopic lesions. The observations in this study indicate that in addition to serogroups A and D of P. multocida, serogroup F also can be highly pathogenic for rabbits and therefore might be a cause of considerable economic loss in commercial rabbit production.     

Salmon poisoning disease in two Malayan sun bears

CASE DESCRIPTION: 2 captive sun bears (Helarctos malayanus) were evaluated because of acute onset of vomiting, mucoid diarrhea, lethargy, and anorexia 1 week after eating live trout from a northern California reservoir. CLINICAL FINDINGS: In 1 of the bears, a CBC and serum biochemical analyses revealed mild anemia, mild eosinophilia, moderate lymphopenia, moderate hypoalbuminemia, and high serum G-glutamyltransferase activity. Ultrasonographic examination of the same bear revealed ascites and mesenteric lymphadenopathy. Histologic examination of gastrointestinal tract biopsy specimens revealed moderate to severe lymphoplasmacytic and eosinophilic gastritis, enteritis, and colitis. Ova of Nanophyetus salmincola, the trematode vector of Neorickettsia helminthoeca (a rickettsial organism that causes salmon poisoning disease), were detected in fecal samples from both bears. TREATMENT AND OUTCOME: The bears were treated with oxytetracycline, doxycycline, praziquantel, and famotidine. Within 1 week after initiation of treatment, the appetite and fecal consistency of each bear were considered normal. Fecal ova shedding began 4 days after onset of clinical signs and ceased 9 days later. CLINICAL RELEVANCE: Salmon poisoning disease can be rapidly fatal in untreated animals, but if diagnosed early and treated appropriately, full recovery can be achieved. Domestic dogs and captive exotic bears are highly susceptible to clinical disease after ingestion of trematode-infected fish. Salmon poisoning disease may develop outside the geographic range in which the causative organism is endemic as a result of the transplantation of infected fish for sport fishing; veterinarians practicing in areas where infected fish may be transplanted should be aware of appropriate diagnostic and treatment protocols.     

接种大豆花叶病毒条件下大豆上位叶离体培养物的生长与形态发生

 本研究从接种大豆花叶病毒(SMV)江苏株系Sa、Sg的大豆植株上取上位叶为外植体,研究不同株系对愈伤组织产生及芽与根分化的影响。结果发现,愈伤组织的诱导率及其形态特点在接种与未接种间无明显差异;接种Sa的其芽分化率低于未接种的,但接种Sg的其芽分化率反略高于未接种Sg的;接种Sa、Sg后,根的发生能力减弱,但对抗病品种的影响小于感病品种。     

确定相贯线上一些特殊点的作图法

提出了圆柱与圆锥正交、圆锥与球偏交、圆柱与球偏交等三种情况下确定相贯线上特殊点的数学模型及相应的作图法,为实现回转体相贯线的计算机辅助绘图提供了理论基础,为实际工程应用提供了一种快速精确的作图方法．     

Boom‐bust like dynamics of invasive black bullhead (Ameiurus melas) in Lake Sava (Serbia)

The life‐history traits and population dynamics of the black bullhead Ameiurus melas (Rafinesque) were studied monthly from August 2009 to December 2012 in Lake Sava in Belgrade (Serbia). This period included a mass mortality event in May 2011 and subsequent population recovery during 2012. Available evidence suggests the mass mortality was caused by European catfish virus that only affected the black bullhead. Changes in key life‐history traits and the recovery potential (increase in catch‐per‐unit‐effort, doubling of young‐of‐the‐year to adult ratio, earlier maturation and increased fecundity) following the mass mortality event suggest population resilience typical of a recurring boom‐bust pattern and demonstrate the species’ capacity to recover rapidly and re‐establish following disturbance. Repeated systematic mass removals of both juveniles and adults (using fyke nets) will be required if future fishery management measures aimed at limiting the population size are to be effective.     

浅议吸收国际标准应重视标准的经济和贸易属性

我国是畜牧业生产大国,畜禽饲养总量已连续多年稳居世界前列,如何将这种生产优势尽快转化为贸易优势和经济优势是我国加入WTO之后畜牧业发展面临的重要问题。我国近年来参与国际贸易竞争的情况表明,以卫生质量标准为表现形式的技术性贸易壁垒是制约畜产品出口的主要障碍。根据WTO相关规则,采用国际标准是突破这种障碍的基本途径之一。本文通过介绍畜产品贸易中的国际标准及我国的采标情况,从标准的经济和贸易属性出发,对采用国际标准的问题进行探讨,以期对我国今后的采标工作有所帮助。1畜产品贸易中的国际标准在畜产品国际贸易协调中发…