两种小型蜘蛛卵袋超微结构与纤维组成

采用SEM和氨基酸自动分析仪对暗蛛科Amaurobiidae白斑隐蛛Nurscia albofasciata和园蛛科Araneidae长脸艾蛛Cyclosa omonaga两种小型蜘蛛卵袋的超微结构、丝纤维和覆盖层的氨基酸组成进行了观察研究,并根据氨基酸的组成和电镜扫描的图片分析了不同直径丝纤维的丝腺来源.结果表明这两种蜘蛛卵袋特征结构与纤维组成有较大差异.白斑隐蛛卵袋呈封闭的圆饼状,由白色框丝层(主要含有大壶状腺丝)、浅棕色外覆盖层(主要含有柱状腺与葡萄状腺丝)和黄色内覆盖层(只含有柱状腺丝)构成,覆盖层较致密.而长脸艾蛛卵袋呈开放的椭球状,由金黄色外覆盖层(主要含有大壶状腺丝)和白色内覆盖层(只含有柱状腺丝)构成,覆盖层较疏松.这些差异可能与它们各自的繁殖策略及若蛛生长发育特点有关.     

大腹园蛛丝腺及其细胞形态的初步观察

运用显微解剖和石蜡切片技术,我们首次对大腹园蛛Araneus ventricosus腹部的5种丝腺的形态进行了分离、拍照和切片观察.研究发现壶状腺腹腔较大,有多根纺管;梨状腺为多细胞腺体、成簇;集合腺有不规则的分支,纺管外附着小结节;葡萄状腺成簇.各类型丝腺腺体细胞明显可见,但未能明显见到不同丝腺腺体细胞的形态区别.同时也发现了几个存疑形态：壶状腺上附着的腺体、壶状腺下导管和壶状腺腺体细胞,它们可能与蜘蛛腺体的退化或发育等相关.     

3种中型蜘蛛卵袋形态特征与纤维组成结构

采用扫描电镜和氨基酸自动分析仪对球蛛科(Theridiidae)温室拟肥腹蛛(Parasteatodatepidariorum)、肖蛸蛛科(Tetragnathidae)肩斑银鳞蛛(Leucauge blanda)及狼蛛科(Lycosidae)猴马蛛(Hippasa holmerae)3种中型蜘蛛卵袋的超微结构和氨基酸组成进行了观察。形态观察表明,这3种蜘蛛的卵袋形态各异,温室拟肥腹蛛卵袋一头尖,呈梨状;肩斑银鳞蛛卵袋呈扁平状;猴马蛛卵袋呈椭球形。扫描电镜观察表明,温室拟肥腹蛛卵袋外覆盖层仅仅由一种均一直径的柱状腺丝组成,而另外2种蜘蛛卵袋外覆盖层主要由柱状腺丝与少量其他丝腺纺出的丝纤维组成。氨基酸组成分析表明,温室拟肥腹蛛卵袋外覆盖层的丝纤维的氨基酸组成与具有保守性的其他种类蜘蛛柱状腺丝心蛋白的氨基酸组成差异较大,这表明其可能含有新的丝心蛋白家族成员。本文根据氨基酸组成与扫描电镜的结果分析探讨了不同直径丝纤维的丝腺来源。     

云南昆明地区三种蛙皮肤显微结构的比较

对昆明地区的多疣狭口蛙、昭觉林蛙及黑斑蛙的背腹皮肤切片的显微结构进行了观察和比较,尤其对它们皮肤腺体的类型和功能进行了比较分析.结果 表明:多疣狭口蛙皮肤比昭觉林蛙及黑斑蛙皮肤含有更多的腺体,尤其是颗粒腺比后两者含量更为丰富,并且在皮下存在许多腺体团,背腹皮肤较后者厚.昭觉林蛙皮肤较黑斑蛙的含有更多的颗粒腺和粘液腺.3种蛙的背部皮肤都含有色素细胞,而除了在多疣狭口蛙雌性腹部观察到少量色素细胞外,另两种蛙在腹部皮肤中均未见色素层.相比之下,昭觉林蛙和黑斑蛙皮肤结构较相似,两者同多疣狭口蛙在皮肤腺体分布及数量上差别较大,这也体现了三者不同的生态适应机制.     

三种蜘蛛丝蛋白组成分析

本文应用高压液相色谱（ＨＰＬＣ）法分析了岳麓山的大腹园蛛Ａｒａｎｅｕｓ ｖｅｎｔｒｉｃｏｓｕｓ（Ｃ．Ｋｏｃｈ,１８７８）,机敏漏头蛛Ａｇｅｌｅｎａ ｄｉｆｆｉｃｌｉｓ （Ｆｏｘ,１９３７）,白额巨蟹蛛Ｈｅｔｅｒｏｐｏｄａ ｖｅｎａｔｏｒｉａ （Ｌｉｎｎａｅｕｓ,１７５７）的丝蛋白的氨基酸组成,以ＳＤＳ－ＰＡＧＥ法测定了大腹园蛛不同丝腺体的未成丝的可溶性丝蛋白的分子量。实验结果表明蛛丝蛋白中占优势的     

牛舌菌凝集素的分离、性质及细胞凝集活性

牛舌菌子实体经生理盐水抽提、硫酸铵沉淀、DEAE-Cellulose和Sephadex G-100柱层析纯化得到牛舌菌凝集素(Fistulina hepatica Lectin,FHL)。FHL经PAGE显示单一条带,SDSPAGE测得其亚基相对分子质量为63．6KD,Sephadex G-100凝胶过滤测得相对分子质量为63KD,FHL中性糖含量为9．7％,IEF-PAGE测得其等电点为5．36。该凝集素对人的A、B、AB和O型血细胞具有凝集作用,对兔红细胞的凝集作用可被乳糖和N-乙酰半乳糖胺所抑制。氨基酸组成分析表明,FHL含有16种氨基酸,其中天冬氨酸和谷氨酸含量较高。FHL对热、酸具有一定的稳定性,经60℃处理10min,仍有较高的活性,在pH3．0～6．0范围内较稳定,但在碱性pH环境中(pH7．0～10．8),FHL的凝集活性下降明显。β-消去反应测得其糖和蛋白质的连接键为O-型糖肽键。抗肿瘤活性测定表明,FHL对HeLa细胞具有明显抑制作用。     

不同生态环境野生大豆的结构比较研究

对生长在不同生态环境的蝶形花科Ｆａｂａｃｅａｅ 大豆属Ｇｌｙｃｉｎｅ 的两个野生大豆Ｇ．ｓｏｊａ 品系进行了扫描电镜观察及比较研究．结果表明,生长在盐渍生态环境的野生大豆茎和叶体表都具有盐腺,盐腺圆球型,基部有一个小柄,着生在盐生野生大豆茎、叶表皮外切向壁的胞间层处．幼嫩的盐腺靠泌盐孔泌盐,成熟的盐腺靠整体破碎释盐．而生长在黑土地生态环境的野生大豆的茎和叶外切向壁未发现有泌盐的盐腺,其茎叶的表皮都呈现出平滑状态．因此两种不同生态环境的同科同属植物在微观结构上显示出明显差异．     

唐古特大黄叶柄的营养成分分析

对唐古特大黄植物地上部分基生和茎生叶柄的常规营养成分及维生素C、氨基酸、无机元素和有机酸进行了分析,结果表明,叶柄蛋白质含量较高,为5．84％,氨基酸组成全面,含量丰富;含有丰富的人体必需无机元素和较高含量的苹果酸。     

悦目金蛛3种蛛丝超微结构和理化特性的初步研究

利用扫描电镜、氨基酸分析仪、X-衍射仪和单纤维电子强力仪分别对悦目金蛛Argiopeamoena拖丝、网框丝和卵袋丝的超微结构和理化特性进行了测试和观察。结果表明,悦目金蛛卵袋不是由一种结构均一的丝纤维构成,而是由直径相差悬殊的Ⅰ型卵袋丝和Ⅱ型卵袋丝2种丝纤维共同组成,该结果对卵袋丝仅由管状腺产生的观点提出了疑问。在氨基酸组成上悦目金蛛拖丝和网框丝相似,但其卵袋丝的氨基酸组成与拖丝和网框丝相比差别明显。另外还发现卵袋丝的强度、结晶度大于拖丝和网框丝,而它的延伸性能却不及拖丝和网框丝。     

海南原指树蛙皮肤腺体的组织学结构观察

两栖动物皮肤的显著特征之一是外分泌腺体遍布全身,这些腺体释放的分泌物在繁殖、交流和防御等方面起重要作用。本研究利用组织学技术,对海南原指树蛙(Kurixalus hainanus)头部、背部、体侧、颏部以及腹部的皮肤样本进行了显微结构(包括H.E、AB-PAS和Masson三色染色方法)和超微结构的观察,并利用线性混合效应模型对皮肤厚度、腺体分布和大小进行了统计分析。显微结构的观察和分析结果显示,海南原指树蛙的皮肤中仅有黏液腺(Ⅰ型黏液腺和Ⅱ型黏液腺)和颗粒腺,未发现特化腺体。皮肤腺体的种类未发现性别差异,但同性别个体的皮肤厚度、腺体的分布和大小存在部位差异,且这些指标在特定部位存在性别差异。皮肤厚度的差异可能与海南原指树蛙的运动方式和繁殖方式相适应,腺体分布和大小的差异可能与防御功能和性别二态性有关。超微结构观察结果显示,黏液腺含有中、高电子密度的黏液颗粒;颗粒腺的分泌颗粒有接触相融的现象,可能是一种物质成熟的阶段性反应。本研究为蛙类皮肤结构、腺体种类和分布提供了基础资料,为后续开展海南原指树蛙挥发性分泌物的化学成分研究提供了形态学基础。     

The synthesis of RNA and silk protein in Galleria mellonella silk glands

The silk protein synthesis in silk glands of Galleria mellonella is preceded by the increase of total RNA content. The levels of the main RNA classes: 28S and 18S rRNA, tRNA as well as poly(A) + RNA change proportionally to the total RNA pool of glands. The fibroin-like silk protein of molecular weight of about 240 000 is characterized by the high content of four amino acids: glycine, alanine, serine and leucine, which account for more than 70% of amino acid residues. This fibroin-like protein is present in the posterior, middle and anterior parts of silk gland of the last instar larvae.     

Molecular characterization and evolutionary study of spider tubuliform (eggcase) silk protein

As a result of hundreds of millions of years of evolution, orb-web-weaving spiders have developed the use of seven different silks produced by different abdominal glands for various functions. Tubuliform silk (eggcase silk) is unique among these spider silks due to its high serine and very low glycine content. In addition, tubuliform silk is the only silk produced just during a short period of time, the reproductive season, in the spider's life. To understand the molecular characteristics of the proteins composing this silk, we constructed tubuliform-gland-specific cDNA libraries from three different spider families, Nephila clavipes, Argiope aurantia, and Araneus gemmoides. Sequencing of tubuliform silk cDNAs reveals the repetitive architecture of its coding sequence and novel amino acid motifs. The inferred protein, tubuliform spidroin 1 (TuSp1), contains highly homogenized repeats in all three spiders. Amino acid composition comparison of the predicted tubuliform silk protein sequence to tubuliform silk indicates that TuSp1 is the major component of tubuliform silk. Repeat unit alignment of TuSp1 among three spider species shows high sequence conservation among tubuliform silk protein orthologue groups. Sequence comparison among TuSp1 repetitive units within species suggests intragenic concerted evolution, presumably through gene conversion and unequal crossover events. Comparative analysis demonstrates that TuSp1 represents a new orthologue in the spider silk gene family.     

The structural genes for three Drosophila glue proteins reside at a single polytene chromosome puff locus.

The polytene chromosome puff at 68C on the Drosophila melanogaster third chromosome is thought from genetic experiments to contain the structural gene for one of the secreted salivary gland glue polypeptides, sgs-3. Previous work has demonstrated that the DNA included in this puff contains sequences that are transcribed to give three different polyadenylated RNAs that are abundant in third-larval-instar salivary glands. These have been called the group II, group III, and group IV RNAs. In the experiments reported here, we used the nucleotide sequence of the DNA coding for these RNAs to predict some of the physical and chemical properties expected of their protein products, including molecular weight, amino acid composition, and amino acid sequence. Salivary gland polypeptides with molecular weights similar to those expected for the 68C RNA translation products, and with the expected degree of incorporation of different radioactive amino acids, were purified. These proteins were shown by amino acid sequencing to correspond to the protein products of the 68C RNAs. It was further shown that each of these proteins is a part of the secreted salivary gland glue: the group IV RNA codes for the previously described sgs-3, whereas the group II and III RNAs code for the newly identified glue polypeptides sgs-8 and sgs-7.     

Silk from crickets: a new twist on spinning

Raspy crickets (Orthoptera: Gryllacrididae) are unique among the orthopterans in producing silk, which is used to build shelters. This work studied the material composition and the fabrication of cricket silk for the first time. We examined silk-webs produced in captivity, which comprised cylindrical fibers and flat films. Spectra obtained from micro-Raman experiments indicated that the silk is composed of protein, primarily in a beta-sheet conformation, and that fibers and films are almost identical in terms of amino acid composition and secondary structure. The primary sequences of four silk proteins were identified through a mass spectrometry/cDNA library approach. The most abundant silk protein was large in size (300 and 220 kDa variants), rich in alanine, glycine and serine, and contained repetitive sequence motifs; these are features which are shared with several known beta-sheet forming silk proteins. Convergent evolution at the molecular level contrasts with development by crickets of a novel mechanism for silk fabrication. After secretion of cricket silk proteins by the labial glands they are fabricated into mature silk by the labium-hypopharynx, which is modified to allow the controlled formation of either fibers or films. Protein folding into beta-sheet structure during silk fabrication is not driven by shear forces, as is reported for other silks.     

Studies on middle and posterior silk glands of silkworm (Bombyx mori) using two-dimensional electrophoresis and mass spectrometry

Silk glands, present in the larval stage of the silkworm, produce threads of silky material to form the cocoon and are mainly composed of three parts: the anterior, the middle, and the posterior silk glands, each playing different roles in silk secretion. High-resolution two-dimensional polyacrylamide gel electrophoresis and computer-assisted analysis were used to investigate quantitative and qualitative differences between the middle and posterior silk glands. Silver staining revealed over 600 spots for each sample, mostly distributed from 15 to 100 kDa with pH 4-7. Computer-assisted image analysis, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and post-source decay technology suggested that there were significant differences in spot distribution and expression between the middle and posterior silk glands. In addition, 98 spots from the posterior silk gland were excised and further investigated following trypsin digestion. The results suggested that more than 20% of the 88 proteins identified were related to heat-shock proteins and chaperones. Redox system and DNA replication proteins involved in silk protein synthesis were also detected in the posterior silk gland. Interestingly, two novel serpin proteins were identified in the middle silk gland, and to a lesser extent in the posterior gland, which were presumed to be involved in regulation of proteolytic activity and protection of silk proteins from degradation.     

Conserved C-termini of Spidroins are secreted by the major ampullate glands and retained in the silk thread

The C-termini of Spidroins produced in the major and minor ampullate glands of spiders are highly conserved. Despite this conservation, no corresponding peptides have been identified in the spinning dopes or the silk filaments so far. To prove their presence or absence, polyclonal antibodies derived against fusion proteins containing the conserved C-terminal regions of both Spidroin 1 and 2 from the spider Nephila clavipes were generated. The antibodies reacted with high molecular weight polypeptides of the corresponding gland extracts and solubilized major ampullate filament and in addition to filament cross-sections. This demonstrates the existence of C-terminal specific peptides in the spinning dope and the mature Spidroins. Both the fusion proteins as well as the proteins contained within the gland lumen showed a reduction in their size under reducing conditions indicating the presence of disulfide bonds. Their high conservation and the biochemical data suggest crucial roles the C-termini play in the formation and/or structure of the corresponding silk filaments.     

Silks produced by insect labial glands

Insect silks are secreted from diverse gland types; this chapter deals with the silks produced by labial glands of Holometabola (insects with pupa in their life cycle). Labial silk glands are composed of a few tens or hundreds of large polyploid cells that secrete polymerizing proteins which are stored in the gland lumen as a semi?liquid gel. Polymerization is based on weak molecular interactions between repetitive amino acid motifs present in one or more silk proteins; cross?linking by disulfide bonds may be important in the silks spun under water. The mechanism of long?term storage of the silk dope inside the glands and its conversion into the silk fiber during spinning is not fully understood. The conversion occurs within seconds at ambient temperature and pressure, under minimal drawing force and in some cases under water. The silk filament is largely built of proteins called fibroins and in Lepidoptera and Trichoptera coated by glue?type proteins known as sericins. Silks often contain small amounts of additional proteins of poorly known function. The silk components controlling dope storage and filament formation seem to be conserved at the level of orders, while the nature of polymerizing motifs in the fibroins, which determine the physical properties of silk, differ at the level of family and even genus. Most silks are based on fibroin β?sheets interrupted with other structures such as α?helices but the silk proteins of certain sawflies have predominantly a collagen?like or polyglycine II arrangement and the silks of social Hymenoptera are formed from proteins in a coiled coil arrangement.     

Aciniform spidroin, a constituent of egg case sacs and wrapping silk fibers from the black widow spider Latrodectus hesperus

Spiders produce high performance fibers with diverse mechanical properties and biological functions. Molecular and biochemical studies of spider egg case silk have revealed that the main constituent of the large diameter fiber contains the fibroin TuSp1. Here we demonstrate by SDS-PAGE and protein silver staining the presence of a distinct approximately 300-kDa polypeptide that is found in solubilized egg case sacs. Combining matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry and reverse genetics, we have isolated a novel gene called AcSp1-like and demonstrate that its protein product is assembled into the small diameter fibers of egg case sacs and wrapping silks from the black widow spider, Latrodectus hesperus. BLAST searches of the NCBInr protein data base using the amino acid sequence of AcSp1-like revealed similarity to AcSp1, an inferred protein proposed to be a component of wrapping silk. However, the AcSp1-like protein was found to display more nonuniformity in its internal iterated repeat modules than the putative AcSp1 fibroin. Real time quantitative PCR analysis demonstrates that the AcSp1-like gene displays an aciniform gland-restricted pattern of expression. The amino acid composition of the fibroins extracted from the luminal contents of the aciniform glands was remarkably similar to the predicted amino acid composition of the AcSp1-like protein, which supports the assertion that AcSp1-like protein represents the major constituent stored within the aciniform gland. Collectively, our findings provide the first direct molecular evidence for the involvement of the aciniform gland in the production of a common fibroin that is assembled into the small diameter threads of egg case and wrapping silk of cob weavers.