家蚕性连锁致死突变的诱发

<正> 家蚕是雌性异型昆虫,雌蚕性染色体组成为ZW,雄蚕为ZZ。W染色体除了有决定雌性的功能外,还没有确认存在其他的生理或形态基因。已知有许多形态和生理的基因位于Z染色体上。凡是Z染色体上的基因所支配的性状表现为性连锁遗传。如果隐性致死突变发生在Z染色体上,就表现     

家蚕有丝分裂染色体研究

以家蚕品种Y1000、Y2000的早期胚胎（蚕卵）为材料，空气干燥法制片，得到具一定长度和缢痕为特征的胚胎体细胞早中期染色体，并对其进行相对长度计算和核型分析。经对23个分散好、完整的分裂相的分析表明：家蚕早期胚胎（蚕卵）有丝分裂早中期染色体中有异型性染色体存在，Z染色体是核型中最长的，通常具有亚端和亚中部次缢痕，W染色体很短，约相当干Z染色体的1／3长。     

家蚕的性别决定分子机制研究进展

家蚕属于雌杂合型生物,性别决定于胚胎细胞染色体组中W染色体的有无,凡有W染色体的个体均为雌性,记为ZW型,雄性为ZZ型。深度测序发现位于家蚕W染色体的雌性决定基因Fem通过piRNA途径决定家蚕性别,位于Z染色体的Masc基因调控雄性胚胎的剂量补偿与决定Bmdsx的雄特异性剪切。本文主要介绍家蚕W染色体上Fem基因的发现及作为性别决定初始信号的作用,以及雄性Z染色体存在的剂量补偿机制和几个性别决定基因的级联调控关系等,并简要分析了该领域仍需要深入研究的内容。     

家蚕的雌性化因子

正Susumu Katsuma及同事回答了让昆虫遗传学家困惑了80多年的一个问题:W染色体怎样决定家蚕(Bombyx mori)和很多其他鳞翅目的雌性特征?在这一系统中,雄性有两个Z性染色体,雌性有一个Z和一个W。作者发现,雌性化因子是来自一个W染色体的、"与PIWI发生相互作用的RNA"(piRNA)。piRNA使位于Z染色体上的一个基因(名为Masc)的产物沉默,该基因编码一个CCCH型锌指蛋白。这种沉默作用反过来对于双性基因(在胚胎中,该基因在性别分化级联     

利用SSR标记对家蚕卵非胶着性基因(Ng)的定位分析

家蚕卵非胶着性基因(No-glue,Ng)位于第12染色体,Ng突变体的雌性成虫生殖器的粘液腺只分泌极少量的粘性物质,因此产下的卵不能粘着而成为天然散卵,是研究家蚕粘液蛋白分泌机制的重要材料。利用雌性家蚕的W染色体和Z染色体间不发生交换的特点,采用产胶着卵的家蚕品系KY和产非胶着卵的家蚕品系巴格达特(Ba)组配正反交群体(Ba×KY)F1♀×KY♂和KY♀×(Ba×KY)F1♂2种材料,分别记作BC1F和BC1M,根据已经构建的家蚕SSR分子标记连锁图谱对Ng基因进行连锁分析及定位。BC1F群体中的所有产非胶着卵的个体均表现出与(Ba×KY)F1相同的杂合型带型;而所有产胶着卵个体的带型与亲本KY一致,为纯合型。筛选出4个与Ng基因连锁的SSR标记,并利用BC1M群体构建Ng基因的SSR标记遗传连锁图,连锁图的遗传距离为51.9cM,与Ng基因最近的引物为S1213,图距为0cM。     

家蚕染色体工程及其应用研究 Ⅰ·Z和W染色体间易位系统的作成

<正> 家蚕染色体数2n=56。雌雄蚕染色体组成不同,在雄蚕是由两条Z染色体和54条常染色体组成(ZZ+27AA),雌蚕是由一条Z染色体、一条W染色体和54条常染色体组成(ZW+27AA)。Z和W是性染色体。已知Z染色体上载有许多基因,如支配油蚕性的os、od,支配     

PCR技术在鸟类性别鉴定上的应用

根据鸟类性染色体连锁基因EE0．6在Z、W染色体上长度的不同，通过选择6对不同的引物，同时设置4种不同的反应条件，分别采用PCR技术对丹顶鹤、黑鹳、琉璃金刚鹦鹉、绯红金刚鹦鹉、鞭苔鹞鹚、戴冕鹤、火烈鸟的Z、W染色体上的EE0．6基因进行了特异性扩增。结果显示，某些引物组合能从雄鸟样品中扩增出1条片段（EE0．6Z，190bp），而雌性鸟样品则能扩增出2条片段（EE0．6W和EE0．6Z，分别为250bp和190bp），但4组引物对6种鸟类EE0．6基因的扩增效果不同。证实，利用PCR技术能对鸟类进行性别鉴定。     

伴性遗传及其在家禽育种上的应用

伴性遗传是基因位于性染色体上的遗传现象。鸟类动物与哺乳类动物相反,凡配子同型的(ZZ)都是公禽,配子异型的(ZW)都是母禽。研究表明,伴性基因主要存在于Z染色体上。当携带有隐性伴性基因的雄性个体与携带显性伴性基因的雌性个体交配时,子代就会出现交叉遗传现象,即女儿表现父亲的     

家蚕性别决定

本文主要阐述家蚕性别决定的研究现状和前景。家蚕的性别是由Ｗ染色体决定的。人们从传统的研究中推定 :有一个雌性化基因Ｆｅｍ位于Ｗ染色体的某一特定部位上 ,但这一基因还没有被克隆出来。近来的研究发现 ,在家蚕中存在着果蝇ｄｓｘ基因的同源体基因Ｂｍｄｓｘ,并对其进行了分析。像果蝇的ｄｓｘ基因一样 ,家蚕的Ｂｍｄｓｘ基因主要通过性别特异性剪接起作用。尽管家蚕的上游性别决定基因与果蝇的上游性别决定基因大不相同 ,但它们有一个共同的下游基因ｄｓｘ (ｄｏｕｂｌｅｓｅｘ )。从Ｗ染色体到Ｂｍｄｓｘ基因的分子级联的确定 ,以及…     

家蚕粗线期染色体核型模式的建立

家蚕染色体核型分析是研究家蚕遗传、变异和基因定位等的重要方法之一。用Luc ia染色体分析软件对家蚕品种大造卵母细胞粗线期染色体的长度和染色粒分布情况作了调查,结果表明:不同细胞的染色体总长度差异较大,同一细胞内各染色体绝对长度也互不相同,而且不同细胞相同序号染色体之间的长度差异也很大,但不同细胞相同序号染色体的相对长度比较接近,差异较小,适合作为建立核型模式的参数。对家蚕粗线期染色体的染色粒分析表明:染色粒在整个染色体群的各条染色体中含量均较高,染色粒相对长度在1%~3%之间的染色体比例最大。综合4种参数,建立了一个家蚕粗线期染色体的核型模式图,初步反映粗线期每条染色体各自的特征。     

Comparisons of Angus, Charolais, Galloway, Hereford, Longhorn, Nellore, Piedmontese, Salers, and Shorthorn breeds for weight, weight adjusted for condition score, height, and condition score of cows

Breed differences for weight (CW), height (CH), and condition score (CS) were estimated from records (n = 12,188) of 2- to 6-yr-old cows (n = 744) from Cycle IV of the U.S. Meat Animal Research Center's Germplasm Evaluation (GPE) Program. Cows were produced from mating Angus and Hereford dams to Angus, Hereford, Charolais, Shorthorn, Galloway, Longhorn, Nellore, Piedmontese, and Salers sires. Samples of Angus and Hereford sires were 1) reference sires born from 1962 through 1970 and 2) 1980s sires born in 1980 through 1987. The mixed model included cow age, season of measurement and their interactions, year of birth, pregnancy-lactation code (PL), and breedgroup as fixed effects for CW and CS. Analyses of weight adjusted for condition score included CS as a linear covariate. The model for CH excluded PL. Random effects were additive genetic and permanent environmental effects associated with the cow. Differences among breed groups were significant (P < 0.05) for all traits and were maintained through maturity with few interchanges in ranking. The order of F1 cows for weight was as follows: Charolais (506 to 635 kg for different ages), Shorthorn and Salers, reciprocal Hereford-Angus (HA) with 1980s sires, Nellore, HA with reference sires, Galloway, Piedmontese, and Longhorn (412 to 525 kg for different ages). Order for height was as follows: Nellore (136 to 140 cm), Charolais, Shorthorn, Salers, HA with 1980s sires, Piedmontese, Longhorn, Galloway and HA with reference sires (126 to 128 cm). Hereford and Angus cows with reference sires were generally lighter than those with 1980s sires. In general, breed differences for height followed those for weight except that F1 Nellore cows were tallest, which may in part be due to Bos taurus-Bos indicus heterosis for size.     

Supplementation of broodmares with copper, zinc, iron, manganese, cobalt, iodine, and selenium

In experiment 1, 6 pregnant mares received a concentrate that contained a trace mineral premix that provided 14.3 mg Cu, 40 mg Zn, 28 mg Fe, 28 mg Mn, 0.08 mg Co, 0.16 mg I, and 0.16 mg Se/kg concentrate (group A). Seven mares received the same concentrate plus 502 mg Zn and 127 mg Cu once daily (group B). No differences (P > .05) in foal growth data, or Cu, Zn, and Fe concentrations of mare milk, mare serum, or foal serum were observed. In experiment 2, 6 pregnant mares received the same concentrate as group A (group C), and 8 mares received the same concentrate fortified with 4× the trace mineral premix (group D). Group C mares had higher serum Zn concentration at 1 day (P < 0.01) and 56 days (P < 0.04). Group C mares had higher milk Fe concentration at 28 days (P < .01), and group D mares had higher milk Cu concentration at 56 days (P < .01). Group C foals had higher serum Cu concentration at 14 days (P < .03). The results from this study provide no evidence to indicate that supplementing late gestating and lactating mares with higher dietary trace mineral levels than those recommended currently by NRC has any influence on foal growth and development, or on the Cu, Zn, and Fe concentrations of the mare milk, mare serum, or foal serum.     

Concentrations of strontium,barium, cadmium,copper, zinc,manganese, chromium,antimony, selenium,and lead in the liver and kidneys of dogs according to age,gender, and the occurrence of chronic kidney disease

This study was conducted to measure the concentrations of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se), and lead (Pb) in canine liver, renal cortex, and renal medulla, and the association of these concentrations with age, gender, and occurrence of chronic kidney disease (CKD). Tissues from 50 dogs were analyzed using inductively coupled plasma mass spectrometry. Cu, Zn, and Mn levels were highest in the liver followed by the renal cortex and renal medulla. The highest Sr, Cd, and Se concentrations were measured in the renal cortex while lower levels were found in the renal medulla and liver. Female dogs had higher tissue concentrations of Sr (liver and renal medulla), Cd (liver), Zn (liver and renal cortex), Cr (liver, renal cortex, and renal medulla), and Pb (liver) than male animals. Except for Mn and Sb, age-dependent variations were observed for all element concentrations in the canine tissues. Hepatic Cd and Cr concentrations were higher in dogs with CKD. In conclusion, the present results provide new knowledge about the storage of specific elements in canine liver and kidneys, and can be considered important reference data for diagnostic methods and further investigations.     

电感耦合等离子-质谱法测定饲料中钠、镁、铬、锰、铁、铜、锌、砷、硒、镉和铅

应用电感耦合等离子-质谱技术(ICP-MS),建立饲料中钠、镁、铬、锰、铁、铜、锌、砷、硒、镉和铅等元素的测定方法。对饲料样品的前处理方法、仪器工作参数和11种元素标准曲线进行优化;并以加标回收、分析方法比对和重复测试说明方法的准确性和精密性。方法在0～1 000 ng/ml范围内线性良好,仪器检出限为0.557 7～5.072 ng/ml,具有良好的精密度,其回收率在88.1%～104.4%之间,相对标准偏差小于5.0%。同时与原子吸收和原子荧光方法进行比对,测定结果相近。所建立的方法简单、快速,可替代原子吸收和原子荧光方法测定饲料中的11种金属元素,为饲料的质量控制提供理想的元素分析方法。     

Granulocyte isolation from whole blood of goat, sheep, cattle, horse, dog, pig, and man

A simple two step procedure for the isolation of caprine, ovine, bovine, equine, canine, porcine and human peripheral blood granulocytes is described. After enrichment of granulocytes by centrifugation, contaminating erythrocytes are lysed hypotonically. Recovery, purity, and viability of the granulocyte suspensions are determined. FACScan analysis of the cell suspensions measuring cellular size by forward and sideward light scatter is compared with the corresponding analysis of whole blood leukocytes. Constituencies of the isolated cell suspensions and loss of granulocyte subpopulations through isolation procedure is discussed with regard to granulocyte function assays.     

Department of Clinical Veterinary Practices, School of Veterinary Medicine, University of Dublin, Trinity College, Ballsbridge, Dublin 4

Circular excised skin wounds in the thoracic and metatarsal regions of the dog were studied. A similar sequence of events took place in the two regions although differences did occur due to the different reactions of the tissues which surrounded the wounds. None of the wound cavities became filled with exudate during the early stages of healing. In the thoracic wounds the cavities were largely filled by the swelling and inward movement of adipose tissue. Epithelium first grew on the wound surface in the sector of the wound that was situated in the direction of hair flow. The average time to complete epithelization was similar in both sets of wounds. A zone of alopecia developed around the wounds.