气相色谱法测定禽蛋中有机氯农药和多氯联苯残留量

建立了同时测定禽蛋中14种有机氯农药(OCPs)和7种多氯联苯(PCBs)的气相色谱法。样品用乙腈超声提取,浓硫酸净化,气相色谱法测定,外标法定量。21种待测化合物在5～200μg/L时线性关系良好,方法定量限为0.3～0.7μg/kg,在5、20、100μg/kg三个加标水平下,鸡蛋空白样品的平均加标回收率为75.1%～103.8%,相对标准偏差为1.41%～6.64%。本法简便、快速、准确、成本低廉,适用于禽蛋中多种有机氯农药和多氯联苯的快速筛查。     

基于SSR标记分析四川省桑树种质资源的群体结构和遗传多样性

利用14对SSR引物对四川省89份桑树种质资源的基因组DNA进行PCR,分析种质资源间的群体结构和遗传多样性。共扩增出迁移率不同的条带65条,多态性条带65条,多态性条带比率达100%;Structure群体结构分析将89份桑树种质资源划分为4个群体,4个群体的多态性信息含量在0.552 0~0.599 8之间,总体为0.657 7;基因多样度在0.554 8~0.600 3之间,总体为0.579 0;等位基因数目在66~76个之间,总体为134个;等位基因丰富度在3.327 2~3.549 1之间,总体为3.983 1;遗传多样性主要来源于品种内,属中等偏高水平;14对SSR引物位点的总基因多样度Ht在0.291~0.931之间,整体为0.699;Nei’s种群内基因多样度Hs为0.287~0.910,整体为0.662;种群间基因多样度为0.003~0.098,整体为0.037;种群间基因分化系数为0.008~0.047,整体为0.053;基因流为2.901~62.000,整体为8.934,遗传变异主要发生在群体内,群体间分化程度低,基因流大。UPGMA聚类分析与群体结构分析结果大致相同,2种分析结果都显示分群无地理迁移规律。     

Diet is a main source of vitamin D in Finnish pet rabbits (Oryctolagus cuniculus)

During the winter time in Finland, sunlight is inadequate for vitamin D synthesis. Many pet rabbits live as house rabbits with limited outdoor access even during summer and may therefore be dependent on dietary sources of vitamin D. The aims of this study were to report the serum 25‐hydroxyvitamin D concentrations in Finnish pet rabbits and to identify factors that influence vitamin D status. Serum 25‐hydroxyvitamin D concentrations from 140 pet rabbits were determined using a vitamin D enzyme immunoassay (EIA) kit. Eleven rabbits were excluded from the statistical analysis because of unclear dietary data. The remaining 129 rabbits were divided into groups depending on outdoor access during summer (no access n = 26, periodic n = 57, regular n = 46) as well as daily diet: little or no hay and commercial rabbit food ≤1/2 dl (n = 12); a lot of hay and no commercial food daily (n = 23); a lot of hay and commercial food <1 dl (n = 59); a lot of hay and commercial food ≥1 dl (n = 35). The range of serum 25‐hydroxyvitamin D concentration was from 4.5 to 67.5 ng/ml with a mean of 26.1 ng/ml. Statistical general linear model adjusted for weight, age and season indicated that diet was associated with vitamin D concentrations (p = 0.001), but outdoor access during summer was not (p = 0.41). Mean 25‐hydroxyvitamin D concentration was significantly higher in the rabbits receiving a lot of hay and commercial food ≥1 dl (33.9 ± 13.2 ng/ml) than in rabbits in other diet groups (24.0 ± 8.5 ng/ml, 21.7 ± 8.1 ng/ml, and 22.2 ± 18.0 ng/ml, respectively). This investigation showed wide variation in 25‐hydroxyvitamin D concentrations among Finnish pet rabbits. Diet remains a main source since outdoor access seems to be too limited to provide adequate vitamin D synthesis for most of them, and the use of vitamin D supplements is rare.     

绵羊放牧绢蒿荒漠草地植物群落多样性及其环境解释

对天山北坡放牧条件下的绢蒿草地进行野外调查,以探讨植物群落物种组成、多样性特征及其与环境因子之间的关系。结果表明:1)绵羊放牧过程中形成了明显的放牧强度梯度,草地利用率适中。通过除趋势对应分析 (DCA)将放牧区内的植物群落划分为8个类型,各类型植物群落的物种多样性有显著差异,且群落间存在异质性;2)采用除趋势对应典范分析法(DCCA)中的前项选择,对所获取的9个环境因子进行筛选,最终土壤有机质含量、粪便量、放牧强度、凋落物生物量、海拔、坡向等6个环境因子成为决定物种分布和群落结构组成的主导因素。DCCA排序结果反映出了实际的生态意义,有机质、放牧强度、粪便量在第一排序轴有明显的梯度变化,而坡向和凋落物则在第2轴上呈现出明显梯度变化,物种和群落也沿着上述环境要素的梯度变化而依次分布,很好地解释了放牧条件下绢蒿荒漠草地物种、群落与环境条件之间的关系。     

硒对山羊子宫内膜淋巴细胞体外活化作用及对其分泌细胞因子的影响

分离妊娠山羊子宫内膜淋巴细胞(Endometrial lymphocyte,EML)后,分别加入4、8、12、16 mg/L的亚硒酸钠进行体外培养,探讨硒对EML的活化作用及其对分泌细胞因子IL-2I、L-4、TGFβ1及TGFβ2的影响。结果显示,8~16 mg/L的亚硒酸钠可显著地促进山羊EML的体外活化(P<0.01),并呈剂量依赖性。EML活化后,对IL-2的分泌呈微弱的促进作用;对IL-4、TGFβ1、TGFβ2的分泌有显著的促进作用。     

PEG模拟水分胁迫对桑种萌发及抗性生理生化指标的影响

以“桂优62号”桑种为材料,在不同浓度高分子量的聚乙二醇（PEG6000）模拟的水分胁迫条件下,以摇床培养方法对其进行萌发培养。测定不同浓度PEG溶液（30％、25％、20％和双蒸水）中萌发种子的相关抗性生化指标,实验结果经统计分析表明,当PEG浓度为30％时,萌发种子中的脯氨酸、可溶性蛋白、可溶性糖和丙二醛的含量均极显著地高于CK（双蒸水）,说明在高浓度PEG溶液处理下能够萌发的种子具有较强的抗水分胁迫的能力,可以作为桑树抗旱育种的选择依据之一。     

Genetic diversity in Tunisian olive accessions and their relatedness with other Mediterranean olive genotypes

Eighty-four olive accessions obtained from the National Conservatory of Boughrara-Sfax (Tunisia), previously evaluated for morphological traits, were analysed with 47 random amplified polymorphic DNA (RAPD) markers. They were compared with other olive genotypes originated from Eastern or Western Mediterranean. The highest and lowest similarities between genotypes, estimated by simple matching algorithm, were 0.98 and 0.40, respectively. A dendrogram based on Ward's method and a factorial correspondence analysis (FCA) showed that most of Tunisian accessions are closely related to olive genotypes originating from the Eastern Mediterranean and some are clustering with genotypes originated from the Western Mediterranean. These findings suggested multiple and complex origin of Tunisian olive. A comparative study between a previous morphological analysis and current RAPD assay was carried out and discussed.     

Encapsulation of shoot tips of guava (Psidium guajava L.) for short-term storage and germplasm exchange

Shoot tips obtained from in vitro grown plantlets of guava (Psidium guajava L.) were encapsulated in calcium alginate beads for short-term storage and germplasm exchange. A gelling matrix of 3% sodium alginate and 100 mM calcium chloride was found most suitable for formation of ideal calcium alginate beads. Maximum percent response for conversion of encapsulated shoot tips into plantlets was obtained on growth regulator free full strength liquid MS medium. The regrowth ability of encapsulated shoot tips was affected by medium strength and sucrose concentrations in the medium. Encapsulated shoot tips could be stored at low temperature (4 °C) up to 30 days with a survival frequency of 25%. After 60 days of storage under minimal growth conditions (sucrose lacking medium), about 75% encapsulated shoot tips were converted into plantlets when subcultured on 3% sucrose containing medium. Plantlets regenerated from encapsulated shoot tips were acclimatized successfully.