利用限性品种淘汰部分雄蚕进行蚕种生产的探讨

家蚕雄蛾可重复进行数次交配,仍然受精良好,而斑纹限性蚕品种可在幼虫阶段提早进行雌雄鉴别.利用限性品种进行在5龄期前淘汰部分雄蚕,由于减少5龄用桑量,可以达到减少投入提高制种效益的目的.试验用洞庭、碧波为材料,取得了理想的制种效果.     

褐圆斑基因对蚕品种性状影响的试验初探

限性褐圆斑斑纹明显易分辨,可在家蚕幼虫3、4龄鉴别雌雄蚕,缓解后期鉴蛹劳动力紧张问题。为了解褐圆斑基因是否影响蚕品种健康性及茧质成绩,2017年、2020年在褐圆斑基因导入过程的不同时期,调查了褐圆斑群体与褐圆斑隐性群体的饲育成绩。两次比较结果一致,即褐圆斑基因对蚕品种健康性及茧质成绩无影响。     

拓展AcMNPV宿主域至家蚕的研究

将核型多角体病毒（Ａｕｔｏｇｒａｐｈａ　ｃａｌｉｐｈａｎｉｃ ｎｕｃｌｅａｒ ｐｏｌｙｈｅｄｒｏｓｉｓ　ｖｉｒｕｓ，ＡｃＭＮＰＶ）与家蚕核型多角体病毒（Ｂｏｍｂｙｘｍｏｒｉ　ｎｕｃｌｅａｒ　ｐｏｌｙｈｅｄｒｏｓｉｓ　ｖｉｒｕｓ，ＮｍＮＰＶ）基因组ＤＮＡ的Ｓｍａ　Ｉ酶切Ｃ片段共转染Ｓｆ细胞，共转染上清液接种到ＢｍＮ细胞中进行扩增，然后在ＢｎＮ中进行空斑分析，挑取多角体空斑进行扩增。发现所得到的病毒即能在Ｓｆ纫胞中增殖，也能在ＢｍＮ细胞中增殖，并产生多角体颗粒。用重组病毒的多角体口服感染幼虫，能引起家蚕幼虫发病。     

家蚕保存种中限性品种的经济性状

家蚕限性系统是通过诱变手段，使载有显性标记基因的常染色体或Ｚ染色体的部分片段易位于Ｗ染色体上，然后与对应的具隐性性状的雄蚕交配，后代自交构成一个系统，使这些显性基因所控制的性状只出现在雌体，从而育成各种限性性状的蚕品种。限性系统的育成为家蚕育种提供了新的素材，其中斑纹限性系统已经在生产上大面积推广，其它限性系统的应用研究也正方兴未艾。本文主要讨论了各限性系统的获得经过及应用前景，介绍了中国农业科学院蚕业研究所保存的部分限性品种的经济性状。     

家蚕五种幼虫斑纹浓淡型间的遗传

以本研究室家蚕基因库保存遗传系统的幼虫斑纹为观察对象，发现暗色斑（P^M）．黑缟斑（P^S）．杲蚕（U）鹑斑（q)．褐圆斑（L）均存在斑纹浓淡程度不同且表型稳定的多型系统。根据杂交后能够识别浓淡型性状分离，将暗色斑分成浓型（P^M3)．中型（P^M2)和淡型（P^M1)，黑缟斑分成浓型（P^S2)．淡型（P^S1)，杲蚕分成浓型（U^2)和淡型（U^1）,鹑斑分成浓型（q^3)．中型(q^2)和淡型（q^1)，褐圆斑分成浓型（L^2)和淡型（L^1)。同种斑纹内浓淡型间相互杂交，整体上均表现为等位基因的遗传模式，相对的浓型对淡型为显性，即：P^M3＞P^M2＞P^M1,P^S2＞PS1,U^2＞U^1,q^3＞q^2＞q^1,L^2＞L^1。     

利用生物卫星搭载家蚕试验初报

１９９２年１２月，利用俄罗斯发射的第１０颗生物返回式科学实验卫星（１９９２年１２月２９日发射升空，１９９３年１月１０日回收，飞行１２天），进行家蚕（ＢｏｍｂｙｓｍｏｒｉＬ．）卵、幼虫、茧和蛹的搭载试验。结果表明，在空间飞行期间，家蚕能完成吐丝、结茧、化蛹、化蛾、交配、产卵、受精、胚胎形成、胚胎发育直至幼虫孵化等重要的生命行为。通过对太空飞行回收试验材料的跟踪观察研究，在回收材料个体中，发现有螯虾蛹、过剩斑纹和三眠蚕的变异，经继代饲养该变异能遗传给后代，地面模拟对照组未观察到相关性状变异的存在。     

新油蚕基因of的发现

新油蚕基因ｏｆ的发现孟智启，伴野丰，土井良宏（浙江省农业科学院蚕桑研究所）（日本九州大学家蚕基因资源中心）家蚕正常幼虫皮肤内含有大量白色尿酸盐结晶呈不透明状。而油蚕因在其真皮细胞内缺乏吸附这种尿酸盐的蛋白质，致使油蚕的皮肤呈透明状［１］。油蚕是一个十...     

家蚕中秋用品种川蚕11号的育成

采用杂交育种方法，育成了强健优质中秋用蚕品种川蚕11号（L8081·L8191×L4朝92·L4白82），系双限性（雌斑限性）四元杂交种。鉴定结果表明该品种较易繁殖，健康性接近对照种，产茧量、产丝量及丝质成绩都高于对照，万蚕茧层量高于对照5.53％，鲜毛茧出丝率19．37％，茧丝长1240m，解舒丝长965m，净度98分，适应四川省及西南地区中秋用种。     

禽类嵌合体技术及其在转基因中应用的研究进展

本文综述了禽类以囊胚层细胞（ＢＣ）和原生殖细胞（ＰＧＣ）为供体细胞的嵌合体制作技术及其在禽类转基因中应用的研究进展。嵌合体技术作为禽类转基因的手段之一具有诸多优点。迄今，禽类ＢＣ和ＰＧＣ为供体细胞的嵌合体制作，体细胞和种系嵌合程度分析的方法已建立，且具有较高的操作成功率和准确性。嵌合体性别分化规律和繁殖机能已作了初步研究。嵌合体技术应用于禽类转基因的方法路线已建立，导入外源基因的供体细胞在形成嵌合     

家蚕幼虫体壁内陷体的发现与研究

经解剖观察，发现家蚕幼虫生殖芽神经中或赫氏腺内存在一种椭球形或球形多层结构的体壁内陷体（ＢＩＴ），５０％以上ＢＩＴ有刚毛结构；层次构造有１～５级；分布位置有原种型和杂交种（Ｆ２）型之分；中系品种多有发生，日系品种偶见发生，中日杂交一代种不发生；雄蚕发生率极显著高于雌蚕；３～５龄蚕发生率和个体发生量差异不明显；秋蚕潮发生率显著高于春蚕期；高温催青饲育发生率增高；从３～５龄蚕ＢＩＴ结构持征推断其在胚胎期形成。     

哺乳动物的极体

长久以来 ,人们都认为极体在正常情况下不参与动物的胚胎发育而退化 ,是无功能的小细胞。但实验证明极体含有的染色体与留在卵母细胞中的染色体具有同等的遗传潜力。在小鼠上 ,人们将其极体与去核卵母细胞或者去核合子融合 ,构成的重构卵母细胞受精后和重构胚都能发育 ,移植后均产生正常生殖力的后代。研究还发现极体的形成与细胞骨架密切相关 ,而其退化则可能是一个凋亡过程。极体作为雌性染色体的来源 ,可以用于建立种子库 ,并能从一个卵母细胞得到四个基因型相同的后代 ,在人类临床上极体可用作孕前遗传疾病的检查材料 ,减少了操作对胚胎的损伤。对极体还需要做进一步的研究。     

猪卵巢卵母细胞的体外成熟和体外受精

将从屠宰母猪卵巢采得的卵母细胞-卵丘细胞复合体(Oocyte-cumulus Cell Complex.OCC)在含PMSG的M199培养40～44小时,卵丘细胞大部分扩散(86.4％)。48.1％(142/295)的卵母细胞排出第一极体(PBI)。将体外成熟的卵母细胞与体外获能精子授精后30～70小时,80.5％(103/128)的卵母细胞受精并可在体外发育到2～8细胞甚至桑椹胚。本文还对裸卵母细胞的体外成熟和体外受精进行了研究,对体外受精卵的早期发育作了观察。实验结果表明:PMSG对诱导卵丘细胞扩散及卵母细胞的全面成熟有重要作用,在OCC中的卵母细胞成熟率高于裸卵母细胞体外授精后8～10小时将受精卵放入改良KRB液培养可使卵裂比例明显提高。     

Ploidy assessment of porcine haploid and diploid parthenogenetic embryos by fluorescent in situ hybridization detecting a chromosome 1-specific sequence, Sus scrofa Mc1 satellite DNA

The aim of the present study was to examine the feasibility of fluorescent in situ hybridization (FISH) for detecting a chromosome 1-specific sequence as a means of assessing the ploidy of porcine parthenotes. In vitro-matured oocytes with the first polar body (PB) were electrically activated; some were treated with cytochalasin B to prevent second PB extrusion (1PB embryos), and the others extruded the second PB (2PB embryos). At the 2-cell stage, one and two FISH signals were detected in each nucleus of 2PB and 1PB embryos, respectively. Almost all cells of blastocysts derived from 1PB embryos retained two signals. In contrast, cells of blastocysts derived from 2PB embryos had two signals. These data demonstrate that FISH analysis allows precise ploidy assessment of porcine parthenogenetic embryos, hence providing a practical means of detecting ploidy transition during parthenogenetic embryogenesis.     

Effect of centrifugation treatment before vitrification on the viability of porcine mature oocytes and zygotes produced in vitro

The aim of the present study was to investigate the effects of centrifugation pretreatment on the viability and nuclear status of porcine in vitro matured (IVM) oocytes and on the developmental competence of in vitro fertilized (IVF) oocytes (zygotes) after cryopreservation by vitrification (Solid Surface Vitrification; SSV). Mature oocytes having the first polar body after IVM and zygotes having the second polar body at 10 h after IVF were centrifuged at 10,000 x g at 37 C for 20 min and then subjected to SSV. Their viability was evaluated by morphological appearance and fluorescein diacetate staining. The nuclear status of oocytes was evaluated 6 h after vitrification. The developmental ability to the blastocyst stage of vitrified zygotes was evaluated after 6 days of in vitro culture. Although centrifugation did not damage the oocytes directly, it drastically reduced the rate of live oocytes after SSV. The rates of vitrification-induced parthenogenetic activation were similar in both centrifuged and non-centrifuged oocytes (42.4 and 47.4%, respectively). Centrifugation had no significant effects on the viability of pronuclear oocytes. The development of vitrified zygotes to the blastocyst stage was significantly lower than that of the control irrespective of centrifugation pretreatment. There was no difference in the cleavage and blastocyst rates between the control and centrifuged zygotes after vitrification. There was also no difference in the total cell numbers of blastocysts between the control and centrifuged zygotes irrespective of vitrification. These results reveal that, in IVM porcine oocytes, centrifugation pretreatment is highly detrimental to cryotolerance; however, in zygotes, it has only a slight effect on viability and does not alter the developmental competence of surviving zygotes.     

皖西白鹅母鹅生殖器官的解剖观察

本试验研究了皖西白鹅母鹅生殖器官的形态特征。试验应用１０只皖西白鹅母鹅，鹅放血致死后，标本用１０％辐尔马林溶液固定，通过肉眼和放大镜观察生殖器官的形态特征，。结果表明成年皖西白鹅母鹅的生殖器官包括卵巢和输卵管两部分，仅左侧发育正常，右侧早已退化，卵巢大小随鹅的年龄和季节有很大变化；输卵管分漏斗部、蛋白分泌部、峡部、子宫部和阴道部五个部分。     

Second meiotic spindle integrity requires MEK/MAP kinase activity in mouse eggs

ERK-type MAP kinase activity is required for normal first meiotic (MI) metaphase spindle dynamics and first polar body formation at the MI/MII transition, and for MII arrest until egg activation. MEK and MAPK, however, remain active until meiosis is completed and pronuclei form, but whether MEK/MAPK activity affects MII spindle function during egg activation has been unknown. Polarized light microscopy revealed that the MII spindle rapidly (within approximately 15 min) lost birefringence upon treatment of the egg with U0126, indicating decreased organization at the molecular level upon MEK inhibition. In contrast, birefringence rapidly increased when MPF was inhibited with roscovitine, and this was similar to the increased birefringence previously shown after fertilization or parthenogenetic activation with Sr(2+). Confocal microscopy indicated that many spindles in U0126-activated eggs had failed to rotate or were dissociated from the egg cortex. Subsequently, abnormally-located midbodies were evident in U0126-induced parthenogenotes. Thus, MEK/MAPK activity is required to maintain the ordered structure of the MII spindle and for normal spindle dynamics during second polar body formation.     

柔嫩艾美耳球虫裂殖生殖阶段超微结构的研究

利用透射电镜对柔嫩艾美耳球虫（Eimeria tenella)裂殖生殖阶段的超微结构进行了观察描述。其第二次裂殖生殖方式为外裂殖生殖，裂殖子侵入宿主细胞后，裂殖子逐渐变圆形成裂殖体，此过程中裂殖子的棒状体首先消失，引后锥体和极环消失、最后微浅、淀粉颗粒和折光体消失。裂殖体长大后，细胞膜下陷，将裂殖体分成几个部分，随后裂殖体进行核分裂成多核裂殖体，此后在靠近细胞核处细胞膜加厚外突，临近部位的细胞膜凹陷，同时近突起部位内膜复合体加厚形成极环，随着时间的推移逐渐形成幼稚裂殖子，幼稚裂殖子后部与残体相连，此过程中裂殖子的锥、极环、微线、棒状体、淀粉颗粒、折光体依次逐渐形成。裂殖子成熟的标志为从残体脱离，裂殖子的膜下微管24根纵向贯穿裂殖子直达顶端和极环相连，裂殖子内部由锥体、锥体前环1、锥体前环2、极环、微线、线粒体、折光体和3－多个棒状体等组成。     

Aging of recipient oocytes reduces the development of cloned embryos receiving cumulus cells

Parthenogenetic activation is an important factor in successful production of cloned mammals. Because it has been reported that aged oocytes are more sensitive to parthenogenetic activation than young oocytes, the present study examined the effects of oocyte aging on the in vitro and in vivo developmental potential of nuclear-transferred (NT) mouse oocytes receiving cumulus cells. The potentials of young NT oocytes (14 h after human chorionic gonadotrophin [hCG] injection) to develop into blastocysts was, however, significantly higher than that of aged oocytes (20 h after hCG injection; 16% vs 6%). When the nuclei of NT oocytes at the 2-cell stage were fused with enucleated fertilized 2-cell embryos, the potentials of the serial NT embryos to develop into blastocysts were no different for both young and aged oocytes (74% vs 74%). Live young, however, were obtained only after transfer of serial NT blastocysts developed from young NT oocytes (2%). In contrast to a report using embryonic nuclei as the nuclear donors, the results of the present study indicate that young oocytes are superior to aged oocytes as a source of recipient cytoplasm for mouse somatic cell cloning.     

Optimization of Ca2+ concentrations in fusion and activation media for production of cloned embryos from miniature pig somatic cells

The effects of Ca(2+) concentration in activation medium and cytochalasin B treatment after activation on the parthenogenetic development of pig oocytes were examined. In addition, cloned embryos derived from miniature pig somatic cells were activated under optimal conditions and the effects of Ca(2+) in fusion medium on the development of embryos after activation was examined. When oocytes were activated in 0.1 mM Ca(2+) and then treated with cytochalasin B, the blastocyst formation rate (28.6%) was significantly higher than those activated in 0-0.05 or 1.0 mM (11.0-18.3%). Treatment with cytochalasin B decreased the second polar body extrusion rate of activated oocytes. The presence or absence of Ca(2+) in fusion medium did not affect the fusion rate of miniature pig somatic cells with recipient oocytes. A few cloned embryos developed to the blastocyst stage (2.7-9.0%) without an additional activation treatment. On the other hand, significantly more embryos developed to the blastocyst stage after activation treatment when they were fused in the absence (28.9%) of Ca(2+) rather than the presence (16.5%) of it. These results show that the highest blastocyst formation rate for miniature pig cloned embryos is obtained when donor cells and recipient oocytes are fused in the absence of Ca(2+) and then activated in 0.1 mM Ca(2+) and treated with cytochalasin B.