The effect of various flooring materials on performance and foot health of early-weaned pigs

The effects of various flooring materials on the performance and foot health of early-weaned piglets were evaluated in seven trials using 728 pigs. Pigs housed on galvanized flattened expanded metal, plastic-coated expanded metal, perforated galvanized panels, galvanized woven wire and plastic-coated woven wire had similar average daily gains, average daily feed intakes and feed/gain ratios. Foot pad scores were lower (less cuts, cracks and abrasions) for plastic-coated expanded metal, plastic-coated woven wire and perforated galvanized panels than for galvanized expanded metal and galvanized woven wire. While foot pad scores varied among flooring materials, none of the flooring materials produced lesions that resulted in any visible discomfort or inhibition of locomotion of the pigs. Correlation coefficients between individual pig body weight and foot pad scores were positively related indicating that body weight may be a factor contributing to lesion severity. Although foot pad lesions were common in the weanling pigs, with some variation due to flooring materials, there were no differential effects among the flooring materials evaluated on performance or visible comfort of the pigs.     

Antigen-nonspecific macrophage factors modulating the antibody response in vitro

Antibody response to an antigen involves the co-operation between three types of cells: macrophages, T cells and B cells. The cognate interactions between these cells play a fundamental role in the expression of a specific antibody response, but the last is modulated by antigen-nonspecific soluble factors produced either by macrophages or by T cells. Macrophages elaborate a spectrum of molecules modulating the function of lymphoid cells; among them are IL1 and prostaglandins of the E series, which are respectively enhancer and inhibitor of the antibody response in vitro. These molecules alter T cell and B cell activities through different mechanisms involving activation or inhibition of IL2 production, or alteration of cells surface antigens. However, the cellular events following the fixation of soluble factor on its receptors are not known.     

木质养殖船的稳性衡准

针对木质养殖船无建造规范可进行稳性衡准,对大连市庄河、长海县、普兰店、开发区部分养殖船进行实船测绘,并对163艘养殖船资料进行了统计与分析,从中总结出适合大连地区木质养殖船的稳性衡准计算方法.     

卵穗山羊草和柱穗山羊草与普通小麦属间杂种的产生及其育性比较

分别以卵穗山羊草和柱穗山羊草为母本,以普通小麦为父本杂交,将获得的杂种再进行回交和自交,对其育性进行比较研究.结果表明,不同的种或品种做母本其可交配性表现不同,卵穗山羊草的结实率(14.10%和11.96%),比柱穗山羊草高(2.13%和8.47%).杂种胚产生愈伤组织率和幼胚直接成苗率不同.柱穗山羊草/小麦杂种胚愈伤组织诱导率高于杂种胚.卵穗山羊草/小麦的直接成苗率高于柱穗山羊草/小麦.卵穗山羊草/小麦用小麦回交的结实率为3.71%;柱穗山羊草/小麦用小麦回交未结实.卵穗山羊草/小麦自交也能结实,自交的结实率为0.044%,柱穗山羊草/小麦杂种自交没有结实.卵穗山羊草/小麦杂种的育性较柱穗山羊草/小麦杂种强,卵穗山羊草基因通过杂交向小麦转移比柱穗山羊草更容易.     

利用组织培养技术向普通小麦导入簇毛麦抗白粉病基因的研究

 对硬粒小麦（T.durum）-簇毛麦（H.villosa）杂种幼胚和F#-1幼穗诱导的愈伤组织进行秋水仙素处理获得硬-簇双二倍体TH1，TH1W，TH2W，TH3，TH3W。平均加倍率为78.8%,最高为94.1%。通过与普通小麦（T.aestivum）回交，幼胚和花药培养，得到了6D/6V异代换系94G22-1，94G25-1，94G32-1，94G33-1。谷草转氨酶（GOT）和酯酶（EST）同工酶可作为这些材料的生化标记。RAPD分析中，引物OPAN3可作为其分子标记引物。     

硬粒小麦-簇毛麦双二倍体与普通小麦杂种BC_1和F_2的细胞遗传学研究

BC_1和F_2植株的染色体数目变异分别为35～49和31～51,基本接近理论分布。其花粉母细胞的平均二价体数较F_1明显上升,分别为16.13和18.10,可见F_2比BC_1上升更多,因而平均自交结实率F_2比BC_1高,但与普通小麦回交结实率基本一致。这说明BC_1和F_2的可育雌配子数相近,而可育雄配子数F_2比BC_1多。因此认为二价体数目对雄配子可育性的影响比较明显,而对雌配子可育性影响比较弱。获得了一批可望产生异附加系和异代换系的2n=49(AABB DDV)、51以及43、44的抗白粉病植株的后代材料。     

Development and Identification of Triticum aestivum L.-Thinopyrum bessarabicum L(o)ve Chromosome Translocations

With ass7istance of chromosome C-banding and genomic in situ hybridization(GISH)combined with meiotic analysis,five germplasms with homozygous wheat-Th. Bessarabicum chromosome translocations were developed and identified among BC1F5 progenies of the cross between T. Aestivum cv. Chinese Spring and Chinese Spring-Th. Bessarabicum amphiploid. These lines included Tj01 and Tj02(2n=44)containing a pair of wheat-Th. Bessarabicum translocation chromosomes besides a pair of added Th. Bessarabicum chromosomes,Tj03(2n=44)with a pair of added interspecific translocation chromosomes,Tj04(2n=44)containing a pair of interspecific translocation chromosomes besides an added pair of Th. Bessarabicum chromosome arms and Tj05(2n=46)containing a pair of interspecific translocation chromosomes besides two pairs of added intact alien chromosomes. The breakpoints of all the translocations were found to be not around centromere. Meanwhile,all the lines showed normal plant growth,development and fertility,while the translocation chromosomes transmitted regularly. The obtained translocations might be of use for transferring elite genes from Th. Bessarabicum into wheat.     

普通小麦与沙生冰草、根茎冰草属间杂种的产生及其细胞遗传学研究

 通过幼胚拯救，首次获得了普通小麦与沙生冰草、根茎冰草两组合的属间杂种。在幼胚拯救时发现，无盾片的幼胚是不能产生杂种苗的。对获得的两组合杂种植株进行了壮苗和破蘖培养繁苗，使来自同一胚的杂种植株数目增加。在获得的F#-1杂种中，幼苗形态和穗型似普通小麦栽培种。在花粉母细胞减数分裂中期Ⅰ，中国春×沙生冰草、根茎冰草两组合杂种F#-1的染色体配对频率远远超出了期望值。对杂种F#-1用四倍体和六倍体小麦回交，都能很容易获得种子，平均结实率都在15%以上。特别值得注意的是两组合的属间杂种均具有自交可育性，自交结实率分别为0.46%和0.15%。文章讨论了：⒈杂交成功的经验；⒉P与A、B、D染色体组间特殊遗传关系的理论分析；⒊F#-1自交结实的原因；⒋壮苗培养和破蘖培养繁苗在小麦远缘杂交中的重要作用。小麦属与冰草属间自交和回交后代的首次获得，在理论上对前人所认为的P染色体组在小麦族中的高度独立遗传性，提供了直接的相反证据；在实践上，使产生异源附加系、代换系甚至易位系、进而为利用P染色体组中的期望基因变得相对的容易。     

加快高校科技成果转化的对策探讨

目前我国高校普遍存在科技成果转化率较低问题。从常见的转化形式分析,是因为缺乏自主开发课题、高校有限资源分散、课题与市场不吻合、科技管理政策不完善、科研经费和中介机构缺乏等原因造成的。而深层次的原因是体制僵化、机制不活。因此如何从体制和机制上寻找解决问题的对策,至关重要。     

簇毛麦染色体的形态学及Gie msa-C带的多态性研究Ⅱ.簇毛麦染色体在人工双二倍体中的C-带变化

对硬粒小麦 -簇毛麦双二倍体纯系的簇毛麦染色体C -显带研究表明 ,纯系中每一条簇毛麦染色体的带型及分布具有相当的稳定性 ,为簇毛麦染色体导入小麦后进行鉴定提供了可靠的保证。双二倍体纯系中的簇毛麦与自然群体中簇毛麦染色体的带型比较发现 ,尽管带型有一定的可比性 ,但仍然存在一定的差异。自然群体的簇毛麦染色体带型多态性远大于纯系 ,特别是 3V和 7V染色体 ,发生了较大变化。因此该结果表明 ,把簇毛麦种质导入小麦后 ,为了对导入的簇毛麦染色体或片段进行准确的鉴定 ,最好采用双二倍体纯系作为供体亲本