Micro-computerized tomographic observation of the spinning apparatus in Bombyx mori silkworms

Silkworms and spiders have evolved complex spinning apparatus thought to use highly controlled conditions to optimize protein folding and crystallization to provide a tough fiber. Accordingly, the structure and function of the natural spinning apparatus has been studied with great attention as an interesting piece of biological engineering with potential for mimicry in an industrial process. However it is still not well understood. Here we used Micro-Computerized Tomographic equipment (mCT) to visualize the three-dimensional structure of the spinning apparatus in Bombyx mori silkworms. Multidirectional tomograms obtained by X-ray radioscopy provided valuable information on the detailed arrangement of each muscle of the silk press. It is suggested that the duct in the silk press part plays a part as an extrusion die whose cross-sectional area can be controlled by muscles to optimize applied stresses in the partially gelled silk within its lumen.     

酸、碱溶液对脱脂蚕蛹的解剖结构影响

将脱脂蚕蛹分别置于清水、1%盐酸溶液和1%氢氧化钠溶液中,100℃浸泡处理20 min,采用电子光学显微分析技术观察脱脂蚕蛹的解剖结构。结果表明:①清水浸泡,蛋白质、甲壳素膨胀;②盐酸溶液浸泡,在蛋白质、甲壳素膨胀的同时,有蛋白的部分分解;③氢氧化钠溶液浸泡,蛋白质、甲壳素膨胀,蛋白质溶解,并伴有部分蛋白的分解。碱对蛋白层与甲壳层的层间有劈开作用。碱液能实现蛋白层与甲壳层的剥离。     

Different feeding and gustatory responses to ecdysone and 20-hydroxyecdysone by larvae of the silkworm,Bombyx mori

The feeding and gustatory responses to ecdysone and 20-hydroxyecdysone were investigated in the silkworm,Bombyx mori. 20-Hydroxyecdysone reduced feeding response strongly in fourth- and fifth-instar larvae, whereas ecdysone had no effect on feeding response. 20-Hydroxyecdysone stimulated the R receptor, the receptor to feeding deterrents, to a great degree. By contrast, ecdysone was much less effective for stimulating the R receptor. These results indicate that ecdysone and 20-hydroxyecdysone have different effects on feeding response due to different interactions with mouthpart chemoreceptors.     

构树皮丙酮抽出物的DEAE—Sephadex分离及GC—MS分析

利用ＤＥＡＥ—Ｓｅｐｈａｄｅｘ分离柱及ＧＣ—ＭＳ对构树皮丙酮抽出物 进行了分离和分析．在丙酮抽出物中中性组分占抽出物的５９．７％，弱酸性 组分和强酸性组分分别占２５．９％和１０．３％．中性组分中不皂化物占 ８９．２％，皂化物仅占８．４％．不皂化物的成分比较复杂，所检出的主要有 甾醇和甾酮类．皂化物中亚油酸占５０％，软脂酸占２１％．弱酸性组分中 ５０％以上是脂肪酸（亚油酸和软脂酸），而没有松香酸．     

Preparation and characterization of PEGDE crosslinked silk fibroin film

To obtain water-insoluble silk fibroin(SF) materials, polyethylene glycol diglycidyl ether(PEG-DE) was selected as a crosslinking agent to prepare SF films(blends). The reaction conditions were optimized for the crosslinking of the SF molecules. The hot water stability of the blends was measured using BCA protein assay and gravimetric analysis. The molecular conformation and crystalline structure of the blends were analyzed by FTIR and XRD, respectively. When the mass ratio of SF:PEG-DE was 1.0:0.8, the hot water loss rate of the SF blends was minimized. PEG-DE could induce SF molecules to form β-sheets during the gel reaction process, resulting in improved crystallinity and hot water dissolved resistance of the blend films. In order to demonstrate the cytotoxicity of the chemical reagents used to crosslink SF, L929 cells were seeded on the blend film(SF:PEG-DE = 1:1) and cultured for 3 days. Cells of L929 readily adhered and spread in the fusiform on the blend film resulting in high cell viability. The extracted liquid from the SF porous film did not inhibit cell proliferation, as estimated by the MTT assay.     

超滤与纳滤膜技术应用于桑叶中1-脱氧野尻霉素分离浓缩的效果观察

选桑叶为原料,以膜通量、膜通量衰减指数、DNJ透过率和杂质去除率为指标,探究三种超滤膜UF1、UF2和UF3对桑叶中1-脱氧野尻霉素（DNJ）分离效果以及两种纳滤膜NF1和NF2对DNJ的浓缩效果.研究结果表明：三种超滤膜中UF2最适于DNJ的分离,UF2-UF3联合处理（即UF3＊）的效果更佳,且两者的最优操作压力分别为0.8MPa和1.5MPa.与NF1相比,NF2蚋滤膜对DNJ的浓缩效果显著,浓缩倍数可以达到10.1,对DNJ的截留率为81.94％,DNJ纯度为4.65％.     

磷酸化处理对蚕蛹多肽结合钙能力的影响

为探索磷酸化处理对多肽结合钙能力的促进作用,以蚕蛹多肽为研究对象,采用不同种类和添加量的磷酸化试剂对其进行磷酸化改性,再与CaCl2反应制备蚕蛹多肽结合钙复合物,并对样品进行钙和磷含量测定、磷酸化位点检测、红外光谱分析和扫描电镜分析.研究结果表明:Na3 PO4、NaH2 PO4、(NaPO3)63种试剂可与蚕蛹多肽发...     

纳豆菌液态发酵制备蚕蛹肽的工艺优化及其抗炎活性研究

为提高蚕蛹的资源利用率和产品附加值,本研究以蚕蛹蛋白为原料,通过纳豆菌液态发酵制备蚕蛹肽.通过单因素实验和响应面试验确定最佳发酵工艺条件;采用脂多糖诱导RAW264.7巨噬细胞建立细胞炎症模型,对最佳发酵工艺参数组合下获得的蚕蛹肽进行体外抗炎活性研究.结果表明:蚕蛹肽的最佳发酵工艺条件为接种量5.0 mL、蚕蛹蛋白添加...     

蚕沙叶绿素铜配合物与DNA的相互作用

文章从蚕沙中提取出叶绿素(CHL),并由此制备得到了蚕沙叶绿素铜配合物(Cu-CHL)。采用琼脂糖凝胶电泳实验研究了在白炽灯光照下Cu-CHL对pBR 322 DNA的切割能力。实验结果表明铜叶绿素对pBR 322 DNA具有光断裂能力,最佳断裂浓度范围为178.5～357μM。并采用紫外光谱、CD光谱和粘度法探讨了二者的结合模式,结果显示其为外部结合模式,结合常数为2.04×106m-1。