Pituitary adenylate cyclase-activating polypeptide

Pituitary adenylate cyclase-activating polypeptide (PACAP) which belongs to the secretin/glucagon/ VIP family has been originally isolated from the sheep hypothalamus on the basis of its ability to stimulate cAMP formation in culture rat anterior pituitary cells. Post-translational processing of the PACAP precursor generates two biologically active molecular forms, PACAP-38 and PACAP-27. The primary structure of PACAP has been remarkably conserved during evolution. The sequence of PACAP-27 exhibits substantial similarities with those of vasoactive intestinal polypeptide (VIP), glucagon and secretin. The gene encoding the PACAP precursor is widely expressed in brain and various peripheral organs, notably in endocrine glands, gastro-intestinal, urogenital tracts and respiratory system. In vivo, and in vitro studies have shown that PACAP exhibits multiple activities especially a trophic activity during ontogenesis, notably in the adrenal medulla and the central nervous system. The biological effects of PACAP are mediated through three distinct receptor subtypes which exhibit differential affinities for PACAP and VIP. The PAC1 receptor, which shows high selectivity for PACAP, is coupled to several transduction systems. In contrast, VPAC1 and VPAC2, which bind with the same affinity for PACAP and VIP, are mainly coupled to the adenylyl cyclase pathway. In conclusion, PACAP is neuropeptide, and it functions as a hypothalamic hormone, neurohormone, neuromodulator, vasodilator, neurotransmitter or trophic factor in the brain and the various organs.

Circulating immunoglobulin A- and immunoglobulin G-secreting hybridoma cells in peripheral blood preferably migrate to female genital tracts. The role of sex hormones

Antigen-specific circulating immunoglobulin-secreting cells (ISC) migrate to various secondary and tertiary lymphoid tissues. To understand the migration of the cells into the genital tract and its regulation by sex hormones, spleen-derived SG2 hybridoma cells secreting immunoglobulin G2b (IgG2b) and Peyer's patch-derived PA4 hybridoma cells secreting polymer IgA were labelled with (3) H-TdR, and intravenously injected into syngeneic mice of both sexes. Using flow cytometry, surface molecular markers of plasma cells, CD38 and CD138, and adhesion molecules, CD49d, CD162, and CD11a were found to be positive in SG2 and PA4 cells, but CD62L, alpha4beta7 and CD44 were not expressed on these cells. The relative distribution indexes (RDIs) of the cells in genital tract and other tissues were measured. The means of RDIs of SG2 and PA4 cells in female genital tissues were 6.5 and 4.5 times as many as the means in male genital tissues, respectively. The treatment of ovariectomized mice with beta-oestradiol significantly increased the RDIs of PA4 cells in cervix and vagina, but decreased the RDIs of SG2 cells in vagina, horn of uterus, uterus and rectum (P <0.05). Progesterone treatment increased the RDIs of PA4 cells in vagina and rectum (P <0.05). The treatment with testosterone significantly increased the RDIs of SG2 and PA4 cells in epididymis and accessory sex glands (P <0.05). These results demonstrate that the female genital tract is the preferable site for the migration of circulating hybridoma cells to the male genital tract, and sex hormones play an important role in regulation of the migration of circulating ISC to genital tracts.

Fridericia liangi sp nov (Enchytraeidae, Oligochaeta) from Changbaishan Mountain, China

We describe one new enchytraeid species, Fridericia liangi sp. nov., from Mt. Changbaishan, Jilin Province, northeastern China. It was collected from soils at the foot of Changbaishan Mountain and is distinguished from all known congeners by the following combination of characters: 1) no lateral chaetae, only ventral chaetae throughout, 2) a maximum of four chaetae in ventral preclitellar bundles, 3) one chaeta in ventral postclitellar bundles, 4) dorsal pores from VII on, 5) esophageal appendages unbranched, 6) coelomocytes without refractile vesicles, 7) clitellum girdle shaped, well developed, 8) no subneural glands, and 9) spermathecae simple.

Three new species of Tubificinae, Oligochaeta, from two plateau lakes in Southwest China

Three new species of Tubificinae (Naididae, Oligochaeta), Varichaetadrilus vestibulatus n. sp., Aulodrilus apeniatus n. sp., and Ilyodrilus mesoprostatus n. sp., are reported from Fuxian Lake and Xingyun Lake of Yunnan Province, Southwest China. V. vestibulatus differs from its allies by possessing modified spermathecal chaetae and thinner cylindrical penial sheaths. A. apeniatus is unique in the genus by having no penis. I. mesoprostatus is distinguishable from congeners by its prostate glands joining middle portion of atria and having concave, cone-shaped cuticular penial sheaths. Twenty-eight species of freshwater oligochaetes have hitherto been recorded from Yunnan Province, including five endemic species from three plateau lakes.

Fridericia dianchiensis sp nov (Enchytraeidae, oligochaeta) from Yunnan Province, China

Fridericia dianchiensis, a new enchytraeid species collected from Yunnan Province, is described here. It is characterized by a combination of the following characters: 1) lateral bundles containing maximum 3 chaetae; 2) esophageal appendages with 3-4 simple, terminal branches; 3) dorsal vessel originating in XX-XXIII; 4) sub-neural glands absent; 5) seminal vesicle large, occupying two segments; 6)clitellum girdle-shaped or gland cells absent between bursal slits and pre-middle ventrally; 7) coelomocytes without refractile vesicles, 8) spermatheca without diverticula and both ampullae broadly united; and 9) long spermathecal ectal duct without gland at the orifice.

Redescription of Nais inflata Liang (Annelida : Oligochaeta) from China

Nais inflata Liang 1963 is redescribed on the basis of fully mature specimens collected from several localities of the Yangtze River and Yellow River. The observations and redescription resulting from the study of mature specimens supports N. inflata as a valid species. This species is characterized by a thickened body, the ventral crotchets all of the same type with distal tooth usually longer than proximal one, a greater number of dorsal chaetae per bundle, stout dorsal needles with equal minute bifid teeth (<1 mu m), presence of penial chaetae, and prostate glands on vasa deferentia instead of atria. The species is most closely related to N. communis Piguet, 1906 and N. variabilis Piguet, 1906. A table comparing allied species is provided.

Potamothrix scleropenis sp nov (Oligochaeta : Tubificidae) from Fuxian Lake, the deepest lake in southwest China

Potamothrix scleropenis sp. nov. (Tubificidae: Tubificinae) is described from the profundal zone (74 m) of Fuxian Lake, the deepest lake (up to 155 m) on the Yunnan-Guizhou Plateau in China. The new species is assigned to Potamothrix because of its short vasa deferentia. and its tubular atria without ejaculatory ducts and prostate glands. It differs from congeners by its cuticularized penis sheaths; bifurcated, strongly curved spermathecal chaetae; bifurcated lower prongs of bifids; and feathered hairs. P scleropenis appears closely related to P cekanovskajae Finogenova, 1972 and P tudoranceai porka, 1994, since all the three species have homogeneous atria without prostate glands.

Bryodrilus fuscistriatus, a new enchytraeid species (Oligochaeta : Enchytraeidae) from northeastern China

Bryodrilus fuscistriatus, a new enchytraeid species from Mt. Changbaishan, Jilin Province, north-eastern China, is described. It is characterized by brown epidermal glands, 7 pairs of preclitellar nephridia, poorly-developed clitellar glands, spermatheca with 2 sessile globular diverticula, and a long sperm funnel with a very broad collar. It is similar to the Alaskan B. tunicatus Dozsa-Farkas & Christensen, 2002 in possessing two diverticula in the spermathecal ampulla and the origin of the dorsal vessel, and the Chinese B. longifistulatus and B. macrotheca Xie et al., 2000c in body size, long sperm funnel and undeveloped clitellar glands, but it differs from B. tunicatus by the presence of brown-striped epidermal gland cells in III-V, a poorly-elevated clitellum, the absence of copulatory glands in XIII-XIV, the regular outline of coelomocytes, and 7 pairs of preclitellar nephridia; from B. longifistulatus and B. macrotheca by the shape of spermatheca, the color of epidermal gland cells, the position of the first pair nephridia, and the origin of dorsal vessel.

The precocious Chinese mitten crab: Changes of gonad, survival rate, and life span in a freshwater lake

Changes of the gonad. survival rate, and life span of the precocious (i.e., sexually mature in their first October-November, at the age of 5 or 6 months) Chinese mitten crab (Eriocheir sinensis) were studied in a small, shallow, macrophytic, freshwater lake along the middle reaches of the Changjiang River, China. The gonosomatic index (GSI) reached peak during the next March when the female GSI was 12.32 +/- 1.75 SD% and the male GSI A as 4.24 +/- 0.19%. The sexual glands degraded from then on. In the first ten-day period of the following July, there was no complete ovum in the ovary. and the sperm became thin and lost adhesion. The population declined sharply from November to July, and the last one (a female) died in the middle of July, which indicated that the life span of the precocious crab was about 12 months (from larval hatching in June to death in July of next year). The survival curve might be expressed as Y = 1.09exp(-0.018x) (Y survival rate; x: days) for the precocious crabs stocked in experimental cages.

Marine Phallodrilinae (Oligochaeta, Tubificidae)of Hainan Island in southern China

Six species of Phallodrilinae are reported from Hainan Island in southern China. The mesopsammic Aktedrilus yiboi sp. nov. is new to science. It is characterized by a combination of (1) small, straight, conical, strongly cuticularized penis sheaths, (2) posterior prostate glands being associated with the most ectal parts of the atria, and (3) small spermathecal ampulla. Bathydrilus ampliductus Erseus, 1997 is recorded for the first time since it was originally described from Australia's Northern Territory.

Four new terrestrial species of Marionina (Clitellata, Enchytraeidae) from China and re-examination of M. hoVbaueri Moller

Enchytraeid surveys were made in China, mainly along the Changjiang (Yangtze) River Basin, during the period 1991-1999. Among the findings, four terrestrial species of Marionina are new to science and well illustrate the taxonomic complexity of the genus as currently defined. Marionina sinica sp. n. is characterized by a specific chaetal distribution, the marionine pattern of the dorsal blood vessel, and elongate, fusiform, spermathecal ectal ducts. Marionina sacculata sp. n. is distinguished by the possession of a pair of pouch-like oesophageal appendages in IV, the lack of lateral chaetae in VII-XI, a marionine pattern of the dorsal blood vessel, and short spermathecal ectal ducts gradually expanding into spherical ampullae. Both M. sinica and M. sacculata have minute bodies (2-3 mm long in vivo) and lack spermathecal accessory glands. The former species shows its closest aYnities with the European M. brendae Rota, 1995, whereas the latter is closest to the German M. hoVbaueri Moller, 1971, for which an amended diagnosis is provided. Marionina seminuda sp. n. has only ventral chaetal bundles, distributed from III onwards and bisetose. It is similar to the Holarctic M. subterranea (Knollner, 1935) in lacking entirely the lateral chaetae and in having the brain incised posteriorly, the dorsal vessel bifurcating behind the pharynx, and coelomocytes containing opaque granules, but diVers from it in having the longest chaetae in preclitellar segments and gland cells distributed all over the spermathecal ectal ducts. Marionina righiana sp. n. is diagnosed by the location of the head pore on the prostomium, the absence of lateral chaetae from VIII ( VII or IX) onwards, the possession of free spermathecae extending backwards through one to four segments, the brain deeply incised posteriorly, the lumbricilline pattern of the dorsal blood vessel, and the opacity of coelomocytes in vivo. Prior to this study, members of the genus so atypical as M. righiana with respect to the position of the head pore and the structure of the spermathecae were known only from South American soils. Until the taxonomy of Marionina has been more thoroughly assessed and revised, the assignment of the four species to this large assemblage should be regarded as tentative.

Fridericia nanningensis, a new terrestrial enchytraeid species (Oligochaeta) from southwestern China

Fridericia nanningensis, a new species from wetland soil of Nanhu Park, Nanning city, the capital of Guangxi Zhuang Autonomous Region in southwest China, is described. It is characterized by 2-4 chaetae per bundle, poorly-developed clitellar glands, slender, unbranched peptonephridia, and spermathecae with 2 ampullar diverticula, a deep constriction in the middle of the ampulla and one large ectal gland. It is closely related to the European species, F. alata Nielsen & Christensen, 1959 and the East European species, F. tubulosa Dozsa-Farkas, 1972 by the shape of peptonephridia and the undeveloped clitellar glands. It differs from F. alata by its shorter body length and fewer chaetae per bundle, its type of coelomocytes (type "c"), its deep constriction in the middle of the spermathecae ampulla and a larger ectal gland, and it differs from F. tubulosa by its pale epidermal glands, its more anterior origin of the dorsal vessel, a deep constriction in the middle of the spermathecae ampulla, shorter ectal duct, and only one ectal gland at the spermathecal orifice.

Raman scattering of folded acoustic phonons in self-assembled Si/Ge dot superlattices

Self-assembled Si/Ge dot multilayers with small, uncorrelated dots fabricated by molecular beam epitaxy in the Stranski-Krastanov growth mode are studied by Raman scattering of folded longitudinal acoustic (FLA) modes. The FLA Raman spectra are analyzed and modeled with respect to mode frequencies and the spectral envelope of mode intensities. The deduced average superlattice properties are consistent with results from atomic force microscopy. The simple Rytov model used for Si/Ge layer structures reproduces very well the frequencies of the FLA modes up to 150 cm(-1). The nonlinearity of phonon dispersion curves in bulk Si for large momenta, however, becomes important for modeling the higher frequencies of observed FLA modes up to 22nd order. The effective dot layer width and an activation energy for thermal intermixing of 2.1+/-0.2 eV are determined from the spectral envelopes of FLA mode intensities of as-grown and annealed Si/Ge dot multilayers. (C) 2004 American Institute of Physics.

姚虻唾液腺三类抗血栓活性蛋白的结构和功能研究

血栓栓塞性疾病严重影响人类的健康，是导致死亡率最高的病因之一。在过去 的几十年中，已经开发了针对血液凝固、血小板激活和聚集、血栓溶解的不同步骤而 起作用的基础和临床药物，但是许多抗血栓药物经常被包括低血压、出血等系统性的 副作用所限制，因此，需要开发新型的更具潜力和特异性的抗血栓药物。 吸血节肢动物与宿主相互作用的分子机制研究是目前国际研究的热点之一，通过 该类研究可以发现大量的具有药用前景的先导分子和提供节肢动物控制策略。我们通 过生物化学、分子生物学以及药理学研究手段首次从中国特有的姚虻（Tabanus yao Macquart）唾液腺发现了同时具有水解纤维蛋白原和抑制血小板聚集的双功能的 丝氨酸蛋白酶Tablysin、纤维蛋白水解酶TY6和腺苷三磷酸双磷酸酶Tabapy等3个家 族的抗血栓活性成分。并研究了这3类因子在牛虻唾液腺中的分子多样性、它们的结 构基础及发挥抗血栓功能的作用机制，通过实验动物模型研究体内外抗血栓能力，深 入解析了牛虻作为传统抗血栓中药的物质基础，为发掘具有良好抗血栓功能的新型候 选药物分子，为传统活血化瘀中药牛虻的现代化开发提供了广阔的思路和打下了坚实 的基础。 研究表明，姚虻纤维蛋白原水解酶Tablysin为一种单链蛋白。其表观分子量为 27kDa。此酶为一种丝氨酸蛋白酶家族的新成员，其活性不受金属离子螯合剂EDTA 和还原剂DTT的影响。血浆蛋白酶抑制剂Aprotinin，α-macroglobulin能部分抑制该 酶活性。此酶适应的pH范围较广（pH 2.4-10.0），但对热变化不具很好的耐受性。 Edman降解法进行氨基酸测序分析发现，此酶的N-末端有封闭现象，后经Q-TOF质 谱分析，确定此酶的部分氨基酸序列。此外，我们成功构建了具有完整性的姚虻唾液 腺cDNA文库，获得2×106 pfu个重组子，进一步的筛选了Tablysin的编码基因。 对此酶的溶栓机制进行分析发现，其具有直接水解纤维蛋白原的活性，不具有纤 溶酶原激活剂的活性。此酶能明显地水解纤维蛋白原的α-链，而对β-链的水解活性较 低，不能水解γ链（α > β > γ）。此酶不能有效地水解纤维蛋白，不会水解层粘连蛋白 （Laminin）和纤维粘连蛋白（Fibronectin）等基质蛋白。不具有出血活性。进 一步探讨此酶的作用机制，发现其能以剂量依赖的方式抑制ADP诱导的血小板聚 集。利用流式细胞仪检测到该酶能与血小板膜糖蛋白受体GPIIb / IIIa结合，因此推测其可能是通过抑制血小板和纤维蛋白原结合的作用机制来抑制血小板 的聚集。 我们通过将目的基因连接到pET-32a+载体，并在大肠杆菌表达体系中得到 了高效表达。体外活性检测表明重组蛋白质与天然产物活性相当，用其检测了 其对角叉菜胶致小鼠尾静脉血栓模型体内血栓形成的影响， 实验结果表明 Tablysin具有明显的抗静脉血栓作用。该工作对有潜力开发成为新型单组分抗血栓 药物的姚虻活性蛋白进行了较为系统的理化性质研究，为该分子的进一步开发和研究 奠定了基础。 我们从姚虻唾液腺中分离纯化到一组具有水解纤维蛋白原α-链活性的酶， 命名为TY6家族。对TY6的生化性质进行研究，表明此酶为一种单链的丝氨酸蛋白 酶，其表观分子量为27 kDa，其活性不受金属离子螯合剂EDTA的影响，但能被PMSF 所抑制。Molish反应显示为阴性，说明此酶不是一种糖蛋白。从姚虻唾液腺cDNA 文库中克隆得到其编码序列，发现该酶家族的编码基因在一级结构上表现出丰 富的多样性。通过Western blotting检测到其能与牛虻叮咬后过敏患者血清特异性IgE 结合。推测该基因的多样性是吸血昆虫适应吸血寄生生活而采取的进化策略。 该工作为牛虻唾液腺抗血栓功能基因的继续筛选和分析奠定了基础，并为牛虻的生物 防治提供了思路和对策。 我们从姚虻唾液腺中分离纯化到一个具有水解ADP活性的酶（Apyrase）， 命名为Tabapy。活性检测发现Tabapy具有明显的水解ADP的活性，并能以剂量 依赖的方式抑制ADP诱导的血小板聚集。通过Western blotting检测到Tabapy能与 牛虻叮咬后过敏患者血清特异性IgE结合。用PCR方法从姚虻唾液腺cDNA文库中 克隆得到编码序列，经BLAST分析表明，该酶与来源于斑虻唾液腺的血小板聚 集抑制剂Chrysoptin具有90％的序列相似性，并经过Q-TOF分析确证，有5个肽段 的氨基酸残基与该cDNA序列推导的多肽链匹配。该工作为研究吸血节肢动物 吸血生理及进一步研究Apyrase的结构和功能打下了基础。