稻属叶绿体DNA限制性片段长度多态性

 对稻属（Oryza）的14个种和李氏禾属（Leersia）的 2个种共 138份材料进行了叶绿体 DNA限制性片段长度多态性的分析。用内切酶EcoRⅠ酶切、4 个叶绿体 DNA探针杂交,共发现10种叶绿体 DNA变异类型。在稻属各个种内没有观察到叶绿体 DNA的变异,叶绿体 DNA变异类型基本上以稻属的染色体组型水平划分,因此认为稻属的叶绿体 DNA在进化过程中变异程度很低。推测 CCDD组的O. alta、O. grandiglumis和O. latifolia 及 CC组的 O.officinalis 和 O. eichingeri各有共同的原始祖先。遗传距离分析显示 CC、CCDD、BBCC组之间亲缘关系很近,这3个组与 EE组亲缘关系也较近。李氏禾属的 2个种 L. perrieri 和 L. tisseranti 与稻属的遗传距离很远。     

大黄鱼♀与黄姑鱼♂杂交F1家系初孵仔鱼的AFLP分析

为了评估大黄鱼♀与黄姑鱼♂杂交F₁在良种培育与遗传学研究中的应用潜力,利用AFLP标记研究了双亲基因在2个杂交F₁家系(HF1和HF2)初孵仔鱼中的传递和分离方式。8对AFLP选择性扩增引物在两对亲本中分别检出478和446个片段。在HF1中,检出片段包括215条母本特异条带(FSB)、165条父本特异条带(MSB)和98条双亲共有条带(MuB),其中,121条(56.3%)FSB、115条(69.7%)MSB和93条(94.9%)MuB传递给了全部后代,其余片段在后代中发生分离。FSB和MSB分离位点的平均显性表型频率之间没有显著性差异。AFLP标记在HF2的传递与分离和HF1相似,只是分离位点的比例较HF1低,而且检出了2个非亲位点。此外,在HF1和HF2中都出现了较高比例的偏离孟德尔定律的分离位点。这些结果表明,大黄鱼♀×黄姑鱼♂杂交F₁初孵仔鱼中同时含有来自双亲的基因;虽然计算结果显示杂交F₁在遗传上略偏向于母本,但是父源基因和母源基因没有明显的选择性丢失;母本特异位点多态比例与大黄鱼种内杂交F₁相当。研究结果为大黄鱼♀×黄姑鱼♂杂交F₁的开发与管理提供了科学依据。     

Clonal structure in Ichthyobacterium seriolicida,the causative agent of bacterial haemolytic jaundice in yellowtail,Seriola quinqueradiata,inferred from molecular epidemiological analysis

Bacterial haemolytic jaundice caused by Ichthyobacterium seriolicida has been responsible for mortality in farmed yellowtail, Seriola quinqueradiata, in western Japan since the 1980s. In this study, polymorphic analysis of I. seriolicida was performed using three molecular methods: amplified fragment length polymorphism (AFLP) analysis, multilocus sequence typing (MLST) and multiple‐locus variable‐number tandem repeat analysis (MLVA). Twenty‐eight isolates were analysed using AFLP, while 31 isolates were examined by MLST and MLVA. No polymorphisms were identified by AFLP analysis using EcoRI and MseI, or by MLST of internal fragments of eight housekeeping genes. However, MLVA revealed variation in repeat numbers of three elements, allowing separation of the isolates into 16 sequence types. The unweighted pair group method using arithmetic averages cluster analysis of the MLVA data identified four major clusters, and all isolates belonged to clonal complexes. It is likely that I. seriolicida populations share a common ancestor, which may be a recently introduced strain.     

沉积物中炭屑对粒度分析结果的影响及预处理方法探讨

通过采用3种不同预处理方法,对52个含炭屑样品进行粒度对比分析。结果表明:炭屑颗粒的混入会造成样品粒度分析结果的失真,具体表现在沉积物样品粗颗粒(>40μm)组分含量明显增加、样品各项粒度参数(平均粒径、中值粒径和偏度)显著增大,且随着炭屑含量的增加,去炭屑前后粒度参数的变化值呈规律性变化。综合理论和经验分析得出,当炭屑含量≥1.7%时,样品必须做炭屑预处理。基于本次实验样品的黄土性状(含黏粒少、分选好、颗粒细等),烧失法(F3)是一种值得推荐的去除炭屑较为彻底的预处理方法。     

基因诊断中DNA序列的快速检测法

目的：探讨一种DNA测序方法在临床中的应用。方法：用纯化试剂盒对PCR产物进行纯化．然后用310自动测序仪测定DNA序列。结果：准确测定了一长度为106bp的DNA序列。结论：本方法不但有快速、简便和准确的特点，尤其还对短片段的DNA更显优势．很适合于临床基因诊断中的测序。     

Field assay of seedling and adult-plant resistance to southern leaf blight in maize

Resistance to southern corn leaf blight is under the control of a single recessive allele, rhm, and can be scored from lesion number, size, type and sporulation in the lesion, which are best expressed by plants growing under field conditions, although resistance also can be measured at the seedling stage. An assay procedure that can unequivocally score disease severity from the seedling stage to post‐flowering in the field is desirable. We analysed pairs of isogenic lines H95/H95rhm and B73/B73Htrhm, the F₂ population of H95 × H95rhm consisting of a total of 687 individuals, and 120 F₃ families, which were inoculated with conidia of Bipolaris maydis race O. The disease ratings were also studied together with the segregation scores of a single copy DNA probe, agrP144. Among 687 F₂ plants derived from the cross H95 x H95rhm, 161 plants were rated as resistant and 526 susceptible, suggesting a 1: 3 ratio. Among the 120 F₃ families, there were 32 susceptible, 58 segregating and 30 resistant rows, fitting the expected 1:2:1 ratio for a single gene model. Using agrP144 as a marker, 99.5% restriction fragment length polymorphism (RFLP) allelic segregation scores corresponded to the disease ratings obtained from field data, indicating that the marker agrP144 is tightly linked to the rhm locus. Similarly, the amplified fragment length polymorphism (AFLP) marker p7m36 also is closely linked to the locus but on the opposite side of the marker agrP144.     

性别效应对家蚕茧质性状QTL定位的影响

家蚕茧质性状的性别效应十分明显。分别以性别效应调整前和调整后的家蚕全茧量、茧层量、茧层率和蛹体质量等数量性状值为基础,对性别效应调整前后的茧质性状作数量性状基因座(QTL)定位比较分析,以探讨性别效应对家蚕QTL定位的影响。结果显示,检测出的控制各性状的上位性位点数、QTL总数以及效应显著的QTL数等,都表现为调整前比调整后要多,有效QTL在连锁群上的分布也表现一定的差异。此结果说明由于性别效应的影响可能会导致检测出控制家蚕茧质性状的上位性位点数和QTL总数的增加及其分布的不同,从而引起QTL分析结果的偏差。     

Interleukin-6 and high mobility group box protein-1 in synovial membranes and osteochondral fragments in equine osteoarthritis

Cytokine production in synovial membranes (SM) and osteochondral fragments (OCF) may influence the development of equine osteoarthritis (OA). In this study, the presence of interleukin (IL)-6 and cytoplasmic and extracellular high mobility group box protein (HMGB)-1 in SM and osteochondral tissue from healthy and diseased equine joints was investigated by immunohistochemistry. Additionally, microscopic synovitis was graded. IL-6 was commonly found in SM cells and in chondrocytes in uncalcified cartilage of OCF, whereas little staining was detected in healthy cartilage. Cytoplasmic and/or extracellular HMGB-1 was widespread only in SM from diseased joints, and also detected in OCF in areas of cartilage damage, fibrous repair tissue, and tidemark reduplication. Joints with OCF and cartilage lesions (without OCF) showed significantly higher median synovitis scores than healthy joints (p = 0.013 and p = 0.042, respectively). The study identifies OCF as a source of inflammatory mediators in equine OA, as shown by the presence of IL-6 and extracellular HMGB-1 in the fragment. Based upon HMGB-1 release in SM and OCF, further studies to investigate possible involvement of HMGB-1 in the pathogenesis of OA are warranted.