Comparative Study of Biological and Technological Characters in Three Generations of Silkworm <Emphasis Type="Italic">Bombyx</Emphasis><Emphasis Type="Italic">mori</Emphasis> L. Ameiotic,Parthenogenetically Cloned Lines

Purpose: Detect any deviation in biologic and technologic characters of eight ameiotic-parthenogenetically cloned lines of Bombyx mori L. from different origins from a normal sexually reproduced control line in three generations.Methods: Comparative study of the three generations was conducted in SES, Vratza, unit of the National Center for Agrarian Sciences of Bulgaria after fixing all environmental rearing conditions.Results: The ameiotic-parthen-clones displayed good parthenogenetic development, although total hatchability was significantly less than the sexually reproducing control populations. Survival rates between clones and control were not significantly different. All clones displayed significantly longer larval periods. Slight decline in second generation, and a steeper one in the third generation were observed for all eight cloned lines in cocoon weight, shell weight, and shell ratio and these differences were statistically significant. Cocoon yield was significantly lower than the control throughout the three generations.Conclusions: Our parthen-cloning method has a high rate of success in comparison to other cloning methods, the cloned progeny populations although were weaker technologically (cocoon weight, shell weight, and shell ratio), the biological characters (parthenogenetic development and survival rate) were not compromised. Further study is needed to determine the thermal needs of the cloned embryos and metabolic rate of all stages.     

A novel recombinant dual human SCF expressed in and purified from silkworm, Bombyx mori, possesses higher bioactivity than recombinant monomeric human SCF

A novel recombinant dual human stem cell factor (rdhSCF) gene was constructed which consisted of a full-length hSCF cDNA plus a truncated hSCF cDNA (1-145 aa), linked by a peptide (GGGGSGGGGSGG) coding region. The rdhSCF gene was cloned into baculovirus transfer vector pAcSecG2T under the polyhedrin promoter control. Silkworm larvae infected with the recombinant virus expressed rdhSCF up to 15,800 units/mL in haemolymph. The specific activity of rdhSCF purified from the haemolymph was up to 3.0 x 10(6) units/mg, about 8.6 times as high as that of monomer rhSCF from Escherichia coli, and about 9.1 times as high as that of monomer rhSCF from insect cell. The binding affinity of rdhSCF to the cell surface receptor was higher than that of monomer rhSCF.     

高效液相色谱法测定僵蚕中草酸铵的含量

目的建立高效液相色谱法测定僵蚕中草酸铵的含量。方法用CaCl2沉淀法作样品前的处理;色谱条件为色谱柱:Sino Chrom ODS-BP(250 mm×4.6 mm,5μm);流动相:磷酸氢二铵水溶液(5 g.L-1,pH 2.50);流速:0.5 mL.min-1;柱温:25℃;检测波长:214 nm。结果草酸铵在15.0~150.0μg.mL-1范围内,峰面积与浓度呈良好的线性关系,r=0.995(n=6),平均回收率为96.5%,RSD为1.5%(n=5)。结论方法简便可靠,灵敏,专属性好,可用于僵蚕中草酸铵的含量测定。     

Neospora caninum antigens displaying virus-like particles as a bivalent vaccine candidate against neosporosis

Neospora caninum is a causative and transmissible agent of dog and bovine neosporosis. The resulting reproductive failures in infected cattle lead to significant economic losses worldwide. However, there is no satisfactory treatment or vaccine currently available to combat this pathogen. Thus, the development of appropriate vaccines to manage its infection and transmission is urgently needed. In this study, we expressed Rous sarcoma virus-like particles (RSV-LP) that displayed dual N. caninum antigens in silkworms. The antigen candidates are modified by adding a transmembrane domain of GP64 protein from Bombyx mori nucleopolyhedrovirus (BmNPV) to the C-terminus of surface antigen 1 (NcSAG1) and SAG1-related sequence 2 (NcSRS2). The NcSRS2 alone or the NcSAG1/NcSRS2 bivalent form displaying RSV-LPs were purified using sucrose density gradient centrifugation. These purified VLPs were then used for immunizations in gerbils, Meriones unguiculatus, to evaluate the anti-N. caninum effects in vivo. The results demonstrated that antigens displaying RSV-LPs in immunized gerbils produced the antigen-specific antibody, leading to a relatively lower parasite load after infections of N. caninum. To the best of our knowledge, this is the first study to present an RSV-LP vaccine displaying bivalent antigens from neosporosis. Taken together, our strategy suggests that silkworm-expressed virus-like particles (VLPs) are promising bivalent vaccine candidates against N. caninum infections.     

人生长激素基因组DNA在家蚕BmN细胞中的瞬时表达

目的 :探讨内含子对外源基因在真核细胞中表达的作用。 方法 :直接将含有 4个内含子和自身信号肽的 1.5 kb全长人生长激素基因直接克隆至真核表达载体 pc DNA3.0 ,然后利用脂质体转染家蚕 Bm N细胞 ,收取细胞上清 ,PAGE电泳和Western印迹分析鉴定表达产物 ;将全长基因序列、缺失第 1内含子基因序列和 c DNA序列的表达载体 ,分别转染细胞后检测各片段表达产物之间的差异。结果 :测序结果表明人生长激素基因组 DNA在细胞内正确转录、剪接。蛋白质电泳分析和免疫学检测证明转染细胞能够有效合成并分泌蛋白质。 EL ISA检测发现 3种基因片段中 ,全长的基因序列在表达效果上要高于后两者 (P<0 .0 5 ) ,其中缺失第 1内含子的序列表达效率较 c DNA序列明显降低 (P<0 .0 5 )。结论 :在家蚕细胞中能够正确表达带有自身内含子和信号肽的人源蛋白基因 ;推测基因的内含子在成体的外源基因表达过程中起着更为重要的作用     

蚕丝相关组织工程支架在肌腱和韧带再生修复中的应用

肌腱和韧带损伤是临床常见运动系统损伤之一。传统治疗手段因供体来源有限、机体免疫排斥等局限,尚无法达到令人满意的临床疗效,尤其是对那些竞技运动员。目前的组织工程学手段能够突破传统治疗的局限,促进肌腱和韧带损伤的修复再生。蚕丝是一种天然的生物材料,具有生物相容性较好、力学强度跨度大和物理结构可调节等特性,可以作为肌腱和韧带的组织工程支架。以蚕丝支架为核心提供力学支持,复合胶原等其他生物成分能增加支架的三维空间,促进更多细胞黏附,并提升材料的生物相容性。体内研究逐步验证了蚕丝支架在发病率较高的肌腱和韧带(前交叉韧带、内侧副韧带、跟腱、肩袖韧带)修复中的临床应用潜能。生物力学良好,宿主自然整合的组织工程肌腱和韧带需要深入基础微观领域研究和延伸临床操作领域研究,促进产品走出实验室,开辟临床应用新航路,为肌腱和韧带损伤患者带来新的希望。本文就蚕丝相关组织工程支架的历史演变及其用于肌腱和韧带损伤修复的效果进行综述和展望。     

Biotransformation Effect of Bombyx Mori L. May Play An Important Role in Treating Diabetic Nephropathy

Compared with herbal drugs, medicine processed from animals(animal medicine) was thought to have more bioactive substances and higher activities. Biotransformation effect often plays an important role in their effect. However, researches about effect of animal medicine on diabetic nephropathy and applying animal medicine as natural bio-transformer were seldom reported. The purpose of this paper was to reveal the use of Bombyx Mori L. on diabetic nephropathy from ancient to modern times. The classical literature indicated that Saosi Decoction(缫丝汤), which contains Bombyx Mori L. or silkworm cocoon, was applied to treat disorders congruent with modern disease diabetic nephropathy from the Ming to Qing Dynasty in ancient China. Modern studies showed that Bombyx Mori L. contains four main active constituents. Among these, 1-deoxynojirimycin(1-DNJ) and quercetin showed promising potential to be new agents in diabetic nephropathy treatment. The concentrations of 1-DNJ and the activities of quercetin in Bombyx Mori L. are higher than in mulberry leaves, because of the biotransformation in the Bombyx Mori L. body. However, these specific components need further human and mechanistic studies to determine their therapeutic potential for this challenging condition.