黄羽肉鸡群体遗传变异的微卫星分析及其与体重杂种优势的关系

选用10对微卫星引物分析了黄羽肉鸡A、B、C3个品系的遗传结构和差异,并对微卫星标记所计算的个体间遗传距离与C×B、C×A杂交后代的初生至8周龄体重的杂种优势和杂种优势率进行了相关分析。结果表明,10个微卫星标记中有9个表现出多态性,多态信息含量(PIC)和群体杂合度(Heterozigosity)分别为0·4400和0·6811,各品系、各微卫星基因座上都表现出一定差异。利用9个多态微卫星标记计算得出的亲本个体间的遗传距离与后代杂种优势率间多数没有显著的相关(P>0·05),仅C×B组合中亲本个体间平均遗传距离与第8周龄体重杂种优势和杂种优势率间相关显著(P<0·05)。     

Habitat Selection and Breeding Success in a Forest-nesting Alcid, the Marbled Murrelet, in Two Landscapes with Different Degrees of Forest Fragmentation

We studied habitat selection and breeding success in marked populations of a protected seabird (family Alcidae), the marbled murrelet (Brachyramphus marmoratus), in a relatively intact and a heavily logged old-growth forest landscape in south-western Canada. Murrelets used old-growth fragments either proportionately to their size frequency distribution (intact) or they tended to nest in disproportionately smaller fragments (logged). Multiple regression modelling showed that murrelet distribution could be explained by proximity of nests to landscape features producing biotic and abiotic edge effects. Streams, steeper slopes and lower elevations were selected in both landscapes, probably due to good nesting habitat conditions and easier access to nest sites. In the logged landscape, the murrelets nested closer to recent clearcuts than would be expected. Proximity to the ocean was favoured in the intact area. The models of habitat selection had satisfactory discriminatory ability in both landscapes. Breeding success (probability of nest survival to the middle of the chick rearing period), inferred from nest attendance patterns by radio-tagged parents, was modelled in the logged landscape. Survivorship was greater in areas with recent clearcuts and lower in areas with much regrowth, i.e. it was positively correlated with recent habitat fragmentation. We conclude that marbled murrelets can successfully breed in old-growth forests fragmented by logging.     

牛GDF9和BMP15基因遗传变异与双胎性状的关系研究

以生长分化因子9(Growth differentiation factor 9,GDF9)基因和骨形态发生蛋白15(Bone morphogenet-ic protein 15,BMP15)基因作为牛双胎性状的候选基因,研究了它们在鲁西牛、秦川牛、南阳牛和中国荷斯坦牛4个品种中的遗传变异,并在鲁西牛群体中研究了其多态位点与双胎性状的关系。结果表明:在鲁西牛中GDF9基因的3′UTR发现缺失突变,而其它3个品种中没有发现该突变。对鲁西牛群体中该多态位点与单、双胎性状之间进行卡方显著性检验表明,单胎牛群体与双胎牛群体基因型分布有极显著的差异(P=0.006),双胎牛群体的B等位基因频率明显大于单胎牛群体。通过生物信息学分析表明,突变体mRNA的二级结构与野生型相比总自由能值差异不大,但突变体mRNA翻译起始位点的二级结构稳定性明显大于野生型。在鲁西牛、南阳牛和秦川牛的BMP15基因中发现编码区第759~762位有GAAA 4个碱基存在缺失突变,但没有检测到突变纯合个体,中国荷斯坦牛中没有检测到该突变。卡方显著性检验表明单胎牛群体和双胎牛群体在该位点基因型组成差异不显著(P=0.947)。     

用荧光定量RT-PCR方法检测猪瘟病毒

为了建立能特异检测不同基因型猪瘟病毒(Classical swine fever virus,CSFV),同时又能区分其他瘟病毒的基因检测方法,本实验针对CSFV基因组5′端非编码区设计并合成了简并引物和TaqMan探针,在优化反应条件的基础上,成功地建立了特异检测CSFV的荧光定量RT-PCR检测方法。再以已知滴度的CSFV石门株血毒总RNA反转录产物建立标准品,该标准品可以用于定量临床样品中的CSFV滴度,所建立的荧光定量PCR方法可以灵敏地检测出10~(-0.82)个TCID_(50)病毒含量。最后用建立的方法对108份临床样品进行检测并同时进行病毒分离,荧光定量PCR方法检测出73份阳性样品且与病毒分离的符合率为100%,而常规RT-PCR只检测出54份阳性样品,表明本荧光定量RT-PCR法在检测猪瘟病料上具有潜在的应用价值。     

"自杀性"DNA疫苗研究进展

DNA疫苗作为第三代全新的疫苗,具有传统疫苗和其他基因工程苗不可比拟的优点.但由于其安全性方面存在着一些尚待解决的问题,使得实际应用受到限制."自杀性"DNA疫苗是基于常规的DNA疫苗和自主复制型RNA疫苗而发展起来的一种新型疫苗.由于其制备原理和过程与常规DNA疫苗相类似,所以它具备常规DNA疫苗在制作、运输储存以及免疫等各方面的优点.同时由于它以甲病毒复制子为基础能诱导转染细胞自主凋亡,故比常规DNA疫苗更为安全有效.文章针对"自杀性"DNA疫苗载体的构建、作用机理、优点以及国内外研究情况作一介绍.     

香蕉A基因组品种间遗传关系的SSR检测

应用SSR技术,对32个香蕉A基因组类型品种(系)的遗传关系进行了检测。40对SSR引物在32个品种(系)中分别扩增带数在3～15个,平均每个SSR座位可检测2.99个多态性带;引物的多态信息量(PIC)在0.00～0.88,平均0.62。依据SSR数据计算的品种间遗传距离在0.00%～34.27%,平均12.45%,大多数品种间的遗传变异非常有限,但也存在着遗传差异突出的品种:FHIA25、Yangambi KM5、Pisang Jari Buaya、Rose和皇帝蕉。依据26%的遗传距离,除了FHIA25和Pisang Jari Buaya单独化成1组外,其它30个品种可以分为2组:品种间遗传差异相对较高的组I和品种间遗传差异相对较低的组Ⅱ。Williams与引进的洪都拉斯3号、M931之间,洪都拉斯1号和洪都拉斯2号之间,高脚青芽蕉和高脚顿地雷分别没有区分开来,这可能是同物异名,也可能是同一品种未能分辨的突变体。     

Comparison of S-RNase,RNase T1, T2, and A effects on growth inhibition and RNA degradation of in vitro-cultured pear pollen

To obtain the basic information on fruit set regulation, effects of several RNases including S-RNase on pollen tube growth and RNA degradation in the tube were studied in the pear. Purified S-RNase from the Japanese pear ‘Kosui’ (S₄S₅) predominantly inhibited the growth of ‘Kosui’ pollen tubes (self) in vitro at 0.28 unit μL⁻¹, but it inhibited ‘Chojuro’ (S₂S₃) pollen (cross) only slightly. The same unit of RNase T₁ (EC 3.1.27.3) clearly inhibited the pollen tube growth, but the action was significantly weaker than that of the S-RNase against the self-pollen. Inhibitory effect of RNase T₂ (EC 3.1.27.1) and RNase A (EC 3.1.27.5) was only slight. The proteins other than the S-RNase extracted from pear style did not have any inhibitory action, though they possessed RNase activity 3.8 times higher than S-RNase. Thus, RNases tested here could not substitute for the S-RNase in specific inhibition against the self-pollen tube growth. Total RNA degradation by each RNase occurred in the pollen tubes as following order; S-RNase (self) ≥T₁ > T₂ ≥ A > S-RNase (cross). Degradation degree of 28S and 18S rRNA was as follows; S-RNase (self) > A > T₁ > T₂ > S-RNase (cross). The degradation of 5.8S and 5S rRNA was; S-RNase (self) > S-RNase (cross) > A > T₂ > T_1. The degree of rRNA degradation was, thus, not always in parallel with the degree of pollen growth inhibition. The S-RNase may degrade not only rRNA but also mRNA essential for pollen tube growth, and may be specifically adapted to inhibit the growth of self-pollen tubes. Therefore, controlling S-RNase amount in the style will produce self-thinning cultivars efficiently, which are unnecessary not only for hand-pollination but fruit-thinning practices in the pear. Practically, cultivar with weak self-incompatibility and small amount of S-RNase, such as ‘Okusankichi’, may be an expecting candidate for breeding self-thinning cultivars.     

Construction and identification of eukaryotic expression vector of bcl-2 siRNA

AIM: To construct eukaryotic expression vector of small interfering RNA(siRNA) specific to bcl-2 and investigate the effect of recombinant plasmid on suppressing bladder cancer cell growth.METHODS: siRNA of bcl-2 gene was designed according to the principle of RNAi-based medicine, and was converted into cDNA coding expression of small hairpin RNAs(shRNA) of siRNA. The cDNA was synthesized and inserted into plasmid pGenesil-1. The recombinant eukaryotic expression vectors of pGenesil-1545 and pGenesil-1555 were controlled by the U6 promoter of RNA polymerase Ⅲ, identified by the restriction map and the sequence analysis, and transfected into T24 cells. After T24 cells were transfected for 72 h, expression of bcl-2 mRNA was assayed by RT-PCR; and MTT was used to observe the proliferation of T24 cells.RESULTS: The recombinant plasmids of pGenesil-1545 and pGenesil-1555 were identified by the restriction map and the sequence analysis. The sequences completely coincided with the designs. The expression of the bcl-2 mRNA in T24 cells transfected with recombinant plasmid decreased nearly 80%, and the growth of T24 cells was suppressed significantly.CONCLUSION: The siRNA eukaryotic expression vector against bcl-2 gene is successfully constructed. It effectively downregulates the expression of bcl-2 in T24 cells and suppresses the cell growth.     

膜孔灌肥液自由入渗硝态氮运移特性试验研究

以KNO3为入渗溶液,模拟研究了硝态氮在膜孔灌肥液自由入渗条件下的运移过程.结果表明,在湿润蜂运移的范围内,沿着膜孔水平方向和垂直方向,硝态氮前锋运移速率受土壤含水量的影响较大,并随着土壤含水量的增加而增加;硝态氮前锋运移速率与运移距离有很好的相关性,并随着运移距离的增加呈幂函数衰减变化.硝态氮前锋浓度随着运移距离的增加而升高,其变化趋势呈指数曲线关系,且在湿润锋(土壤干湿交界)面上达到最大值;硝态氮前锋浓度随土壤含水量的增加呈幂函数递减,两者的相关系数也达到了极显著水平.