Studies on an Indian polydesmoid millipede Streptogonopus phipsoni Life cycle and swarming behaviour of the larvae

The adults of Streptogonopus phipsoni (Pocock), an Indian polydesmoid millipede, emerge from the soil at the onset of the monsoon and mate. Eggs are laid in the soil and the adults die. The larvae leave the soil at stadium III and, apart from moulting periods, remain on the surface until the end of the monsoon. The larvae are aggregated in swarms, usually consisting of several hundred individuals. They are active on open ground, including metalled roads, during daylight, but usually spend the night in an inactive state under cover of stones or vegetation. If a swarm is disturbed, the individuals scatter but later reaggregate.
Laboratory experiments show that the larvae are sensitive to light even though they lack eyes, and if given a choice spend more time in the light than the dark. Just before and after moulting however they spend more time in the dark than in the light.
Experiments were carried out on the reactions of the larvae to aquatic suspensions of benzaldeyde, since this substance is related to components of the exudate of the repugnatorial glands; strong concentrations (10^-1) repelled the larvae, whilst weak concentrations (10^-6) attracted them. It is suggested that swarms may be dispersed or reaggregated by the effects of variations in concentration of components of the exudates. The benefits to the larvae which may result from swarming are discussed.     

The biology of beta-adrenergic receptors: analysis in human epidermoid carcinoma A431 cells.

1. G-protein-linked transmembrane signaling has emerged as a major pathway for information transduction across the cell membrane. 2. In addition to photopigments that propagate the signal from light, cell-surface receptors for hormones, neurotransmitters, and autacoids propagate signals from ligand binding to membrane-bound effector units via G-proteins. 3. Biochemical and molecular features of one prominent member of these receptors, the beta-adrenergic receptor, will be highlighted in the present article. 4. The role of the human epidermoid carcinoma A431 cells as a model for the study of the structure and biology of beta-adrenergic receptors will be emphasized. 5. A model for receptor regulation, gleaned from recent advances in the biochemistry, cell and molecular biology of beta-adrenergic receptors, is discussed.     

The insulin A and B chains contain sufficient structural information to form the native molecule

Refolding studies show that native insulin can be reformed from A and B chains only. This suggests that the A and B chains contain the necessary structural information and that the C peptide is not required for this process.     

固氮蓝藻“红圈病”的研究——Ⅰ.“红圈病”在大面积培养蓝藻中的危害以及防范措施

对蓝藻“红圈病”的病症、发病条件、传播程度方式、危害进行了研究。结果表明,发病条件与蓝藻最佳生长条件基本一致;病原通过水体和带病藻体传播,对藻的产量和质量均造成严重危害。同时探讨了综合防治措施。     

基因定点诱变删除及天然α型心钠素的分泌型表达

用基因定点诱变技术,删除了pO_1α ANF表达质粒中的33对碱基,使人α型心钠素结构基因直接与大肠杆菌分泌型表达质粒pIN-Ⅲ-OmPA中的信号肽酶切位点编码区相连,构成天然人α型心钠素的表达质粒pANF,在IPTG诱导下表达28肽的天然人α型心钠素。纯化后的表达产物具有天然心钠素的放免活性和很强的舒张血管的生物活性。     

The disulfide bridge pattern of snake venom disintegrins, flavoridin and echistatin.

Flavoridin and echistatin, isolated from the venom of Trimeresurus flavoviridis and Echis carinatus, respectively, belong to the disintegrin family of integrin beta 1 and beta 3 inhibitors of low molecular weight RGD-containing, cysteine-rich peptides. Since disulfide bonds are critical for expression of biological activity, we sought to determine their location in these two proteins. In flavoridin, direct evidence for the existence of linkage between Cys4-Cys19 and between Cys45 and Cys64 was obtained by analysis of proteolytic products, and indirect evidence suggests links between Cys6-Cys14 and Cys13-Cys36. In echistatin, links between Cys8-Cys37 and Cys20-Cys39 were identified by direct chemical analysis.     

Primary structure of human thromboxane synthase determined from the cDNA sequence.

Polymerase chain reaction techniques have been used to isolate a cDNA clone containing the entire protein coding region of thromboxane A2 synthase (EC 5.3.99.5) from a human lung cDNA library. The cDNA clone hybridizes with a single 2.1-kilobase mRNA species in phorbol ester-induced human erythroleukemia and monocytic leukemia cell lines. A second cDNA, differing only by an insert of 163 base pairs near the 3'-end of the translated region, was also found to be present in the same library. The proteins predicted from both nucleic acid sequences include the three polypeptide sequences determined from amino acid sequencing of the purified human platelet enzyme, five potential sites for N-glycosylation, and a hydrophobic region that may serve to anchor the synthase in the endoplasmic reticulum membrane. The longer predicted protein, designated thromboxane synthase-I, contains 534 amino acids, with a Mr of 60,684, whereas the shorter protein, designated thromboxane synthase-II, contains 460 amino acids and has a Mr of 52,408. Although thromboxane synthase-II lacks the conserved cysteine that serves as the proximal heme ligand in the other cytochromes, significant sequence similarities exist among thromboxane synthase-I and -II and several P450s, particularly those in family 3. The overall amino acid identity is considerably less than 40%, making it likely that thromboxane synthase represents a previously undefined family of cytochrome P450.