酸水解蚕蛹制备复合氨基酸的研究

采用硫酸水解法,以蚕蛹制取复合氨基酸产品,得到氨基酸态氮分别为９．０５％和１３．４５％的食用复合氨基粉和精制复合氨基酸粉。食用复合氨基酸粉含有１８种氨基酸,其中必需氨基酸含量为３９．２％。食用复合氨基酸粉的制备方法经工厂小批量生产证实,其工艺简单易行,适合于中小企业采用,该产品的质量优良,生产成本低廉,具有市场竞争力。     

激光诱导家蚕孤雌生殖的研究——Ⅴ.突变体蛹血酯酶同工酶的分析

试验用聚丙烯酰胺凝胶电泳,对激光诱导家蚕孤雌生殖新育成的突变体Lamp_1和Lamp_2蛹血EST同工酶进行了分析。结果说明这两个突变体是新突变体,客观存在的酶谱特征不同于未用激光照射的CK蚕种。     

Immunocytochemical location of vitellin in the egg of the silkworm,Bombyx mori,during early developmental stages

Summary Vitellin was purified from eggs of the silkworm,Bombyx mori, by a new method in which vitellin was extracted from isolated yolk granules. The purified vitellin had a molecular weight of 540,000. An antibody against purified vitellin was prepared in rabbits. It reacted with the hemolymph vitellogenin as well as with purified vitellin, but not with other proteins in the hemolymph or in the extract from yolk granules. The anti-vitellin IgG was used to immunocytochemically locate vitellin in theBombyx non-diapause egg during early developmental stages. In the egg, just after oviposition, vitellin was located in internal yolk granules and in small yolk granules of the periplasm. During the early developmental stages studied, vitellin was not metabolized uniformly throughout the egg. The vitellin of the internal yolk granules located at the posterior-dorsal part and of the small peripheral yolk granules was utilized in 16 h and 2 days, respectively, after oviposition. A thin, very vitellin-poor layer was located between the periplasm and the vitellin-rich interior in the newly laid egg. it was always in close contact with the periphery where blastoderm and germ-band cells developed.     

Comparative proteomics analysis of silkworm hemolymph during the stages of metamorphosis via liquid chromatography and mass spectrometry

The silkworm is a lepidopteran insect that has an open circulatory system with hemolymph consisting of blood and lymph fluid. Hemolymph is not only considered as a depository of nutrients and energy, but it also plays a key role in substance transportation, immunity response, and proteolysis. In this study, we used LC‐MS/MS to analyze the hemolymph proteins of four developmental stages during metamorphosis. A total of 728 proteins were identified from the hemolymph of the second day of wandering stage, first day of pupation, ninth day of pupation, and first day as an adult moth. GO annotations and categories showed that silkworm hemolymph proteins were enriched in carbohydrate metabolism, proteolysis, protein binding, and antibacterial humoral response. The levels of nutrient, immunity‐related, and structural proteins changed significantly during development and metamorphosis. Some, such as cuticle, odorant‐binding, and chemosensory proteins, showed stage‐specific expression in the hemolymph. In addition, the expression of several antimicrobial peptides exhibited their highest level of abundance in the hemolymph of the early pupal stage. These findings provide a comprehensive proteomic insight of the silkworm hemolymph and suggest additional molecular targets for studying insect metamorphosis.     

“两广二号”家蚕抗病毒基因Bmlipase-1和BmSP-2克隆与原核表达

本研究以优良杂交品种"两广二号"家蚕为试材,克隆了该杂交品种家蚕两个抗家蚕核型多角体病毒(BmNPV)基因:脂肪酶基因Bmlipase-1和丝氨酸蛋白酶基因BmSP-2,测序并分别与不同品种蚕的同源基因序列进行比较。结果显示,"两广二号"家蚕Bmlipase-1基因ORF长度为885bp,编码294个氨基酸,BmSP-2扩增长度为855bp,编码284个氨基酸;它们的核苷酸和推导氨基酸序列同源性皆达92%以上,Bmlipase-1更保守,同源性大于99%";两广二号"家蚕的Bmlipase-1基因脂肪酶活化部位和BmSP-2基因酶催化三联体位点的氨基酸残基与不同品种蚕的完全相同。以上结果说明这两个抗病毒基因在蚕的遗传进化过程中高度保守,提示其可能在机体消化或者免疫防御方面起着重要生理作用。将这两个抗病毒基因在大肠杆菌BL21中进行融合表达,获得的融合Bmlipase-1和BmSP-2蛋白分子量分别为47kD和42kD左右。     

Efficient Protein Expression in <Emphasis Type="Italic">Bombyx mori</Emphasis> Larvae of the Strain d17 Highly Sensitive to <Emphasis Type="Italic">B. mori</Emphasis> Nucleopolyhedrovirus

The recombinant protein expression by Bombyx mori nucleopolyhedrovirus (BmNPV) infecting silkworm larvae or pupae may endow us with a potent system for the production of large eukaryotic proteins. However, the screening of silkworm strains ideally suited to this method has scarcely been conducted. In the present study, we injected recombinant BmNPV containing a reporter gene, luciferase or DsRed, into hemocoel of fifth instar larvae of selected 12 silkworm strains. Among them, the strain d17 is found to be the highest in reporter expression from the intrinsic polyhedrin promoter of Autographa californica NPV or the silkworm actin A3 promoter. These results suggest that the d17 strain is highly permissive for BmNPV replication and is the most likely candidate of a “factory” for large-scale expression using the BmNPV bacmid system.     

家蚕线粒体ND2、COⅠ和若干tRNA基因的克隆及序列分析

克隆并测定了家蚕（Bombyx mori）线粒体基因组3468bp的EcoRⅠ和HindⅢ双酶一段序列,根据序列同源性比较,该DNA片段包括3个蛋白质编码基因：ND2基因、COⅠ基因和COⅡ基因5′端399bp的序列,以及6个tRNA基因和一个尚待确定的tRNA^Met基因。家蚕与果蝇的ND2基因序列同源性约69.7%,COⅠ基因的同源性约83.8%,COⅡ基因5′端的同源性约80％,这表明细胞色素氧化酶基因在物种间比烟酰胺腺漂呤二核苷酸脱氢酶基因保守,6个推定的tRNA基因序列与果蝇相应tRNA基因序列差异较大,另外,除tRNA^Chn基因的二级结构相似外,其它tRNA基因的二级结构与果蝇相应tRNA基因的二级结构也有较大差异。     

Genetically identical copies of the mulberry silkworm

Summary Genetically identical copies of the silkworm female obtained via ameiotic parthenogenesis are insignificantly depressed by artificial reproduction, and notwithstanding their isogenous pattern, they show the same variability in quantitative characters as in the heterogenous forms.By means of androgenesis, genetically identical copies of strictly homozygous males were obtained; the latter were produced via meiotic parthenogenesis. The androgenetic clones of these males were transformed by backcrosses into homozygous bisexual lines. Viability and cocoon weight in these lines were higher than those in androgenetic clones of similar genotype, but they were far from the norm due to the depressing effect of semilethals left in them in a homozygous state. An extremely low phenotypical variability of quantitative characters is observed in the isogenous hybrids F₁ obtained from crossing two genetically dissimilar strictly homozygous individuals. These hybrids make excellent material for phenogenetical studies. The female and male isogenous clones have an increased combining ability which is acquired in the course of their selection for high disposition towards complete parthenogenesis. For practical purposes it is proposed to take a female and a male which when mated produce a high-quality family and clone them separately, the first via parthenogenesis, the latter via androgenesis. After mating these reproduced bisexual clones, it will be possible to obtain in successive generations a vast number of families repeating the prominent productivity of the initial family.     

Characterization of Tudor-sn-containing granules in the silkworm,Bombyx mori

The Tudor-sn protein, which contains four staphylococcal nuclease domains and a Tudor domain, is a ubiquitous protein found in almost all organisms. It has been reported that Tudor-sn in mammals participates in various cellular pathways involved in gene regulation, cell growth, and development. In insects, we have previously identified a Tudor-sn ortholog in the silkworm, Bombyx mori, and detected its interactions between with Argonaute proteins. The role of Tudor-sn in silkworm, however, still remains largely unknown. In this study, we demonstrated that silkworm Tudor-sn is a stress granule (SG) protein, and determined its interactions with other SG proteins using Bimolecular Fluorescence Complementation assay and Insect Two-Hybrid method. Depletions of Argonaute proteins and SG-marker protein Tia1 by RNAi impaired the involvement of Tudor-sn in the SG formation. Protein domain deletion analysis of Tudor-sn demonstrated that SN2 is the key domain required for the aggregation of Tudor-sn in SGs.