Active compounds in Populus nigra L. wilted leaves responsible for attracting Helicoverpa armigera (Hübner) (Lep., Noctuidae) and new agaropectin formulation

Abstract:  The leaf extracts of Populus nigra were collected and identified by steam distillation, air entrainment and gas chromatographic–mass spectrometric analysis. Electroantennograms were recorded from Helicoverpa armigera adults in response to the chemicals identified. Both aromatic compounds and green-leaf volatiles elicited strong responses. Field experiments revealed that the active compounds responsible for attracting H. armigera moths are mainly short-side-chain aromatic alcohols and aldehydes. We, for the first time, used agaropectin as the controlled-release matrix of insect attractants. A five-component lure containing all the aromatics without phenolics, mixed in the proportions as found in the steam distillate of the leaves collected in August, produced the best trap catch. The results showed that the volatiles of wilted leaves of P. nigra can attract H. armigera adults by feeding attraction.     

The disaccharide composition of heparins and heparan sulfates

Heparin and heparan sulfate can be cleaved selectively at their N-sulfated glucosamine residues by direct treatment with nitrous acid at pH 1.5. These polymers can also be cleaved selectively at their N-acetylated glucosamine residues by first N-deacetylating with hydrazine and then treating the products with nitrous acid at pH 4. These procedures have been combined and optimized for the conversion of these glycosaminoglycan chains into their disaccharide units. A modified hydrazinolysis procedure in which the glycosaminoglycans were heated with hydrazine:water (70:30) containing 1% hydrazine sulfate gave rapid rates of N-deacetylation and minimal conversion of the uronic acid residues to their hydrazide derivatives. Under these conditions, N-deacetylation was complete in 4 h and the beta-eliminative cleavage of the polymer chains that occurs during hydrazinolysis (P. N. Shaklee and H. E. Conrad (1984) Biochem. J. 217, 187-197) was eliminated. Treatment of the N-deacetylated polymer with nitrous acid at pH 3 for 15 h at 25 degrees C then gave simultaneous cleavage at the N-unsubstituted glucosamine residues and the N-sulfated glucosamine residues. These deamination conditions minimized, but did not eliminate, the side reaction in which nitrous acid-reactive glucosamine residues undergo ring contraction without glucosaminide bond cleavage. Thus, the disaccharides were obtained in a yield of 90% of those originally present in the glycosaminoglycan chains. Since the ring contraction side reaction occurs randomly at the diazotized glucosamine residues, the disaccharides formed in the pH 3 nitrous acid reaction were recovered in proportions equal to those in the original glycosaminoglycan chain.(ABSTRACT TRUNCATED AT 250 WORDS)     

人体小卫星DNA探针的制备

根据人体小卫星DNA核心顺序,化学合成长23碱基寡核苷酸探针,筛选人体基因组文库,旨在获得能用作遗传分析探针的小卫星顺序。结果得到15个含小卫星的阳性重组子。随机取其一(C_(35.9))作探针,试做群体分析。所有个体均可检出多条杂交带。其中某些带具有多态性。在一定检测条件下,检出的DNA图谱在有限的个体内具有个体特异性。结果表明筛选文库得到的小卫星顺序可用于小卫星多态性的检测。其它小卫星探针的筛选和应用性研究正在进行。     

Inhibition of gastric acid secretion by peptide YY is independent of gastric somatostatin release in the rat

The purpose of this study was to determine whether the inhibitory action of peptide YY (PYY) on gastric acid secretion is attributable to the release of gastric somatostatin in rats. Two groups of rats (six rats/group) were anesthetized with urethane and prepared with gastric fistulas and jugular catheters. Pentagastrin (18 micrograms/kg-h) was given intravenously for 150 min to stimulate gastric acid secretion. Intravenous PYY (130 micrograms/kg-h) inhibited pentagastrin-stimulated gastric acid secretion significantly (P less than 0.05). Administration of iv PYY resulted in a 41% reduction (P less than 0.05) in pentagastrin-stimulated gastric acid secretion. In another group of anesthetized rats, administration of PYY (10(-7), 10(-8) M) failed to stimulate a release of somatostatin from the isolated-perfused rat stomach. Our findings indicate that PYY can inhibit gastric acid secretion independently of release of gastric somatostatin in the rat.     

头端延髓腹外侧区注射5—羟色胺对应激性高血粘度...

Experiments were carried out on 62 wistar rats. The hyperviscosity and elevation of blood pressure were induced by hanging and restraining the rats with their four limbs tied on a frame. It was found that microinjection of 5-HT (25 micrograms/10 microliters) into the 4th ventricle of the brain or bilateral microinjection of 5-HT (4 micrograms/0.5 microliters/site) into rostral ventrolateral medulla (rVLM) reduced stress-induced hyperviscosity (p < 0.01) and elevation of blood pressure (p < 0.01). The effect of 5-HT injected into the 4th ventricle or rVLM was blocked by bilateral microinjection of cinanserine (4 micrograms/0.5 microliter/site) into rVLM. These results suggest that microinjection of 5-HT into 4th ventricle and rVLM could reduce stress-induced hyperviscosity and elevation of blood pressure and these effects were probably mediated via 5-HT receptors in the rVLM.     

Structure and sequence of the human α- -iduronidase gene

In humans, a deficiency of the lysosomal hydrolase α- -iduronidase (IDUA; EC 3.2.1.76) results in the lysosomal storage of the glycosaminoglycans heparan sulfate and dermatan sulfate, thereby causing the lysosomal storage disorder mucopolysaccharidosis type I. The gene for IDUA is split into 14 exons spanning approximately 19 kb. We report the sequence of two noncontiguous segments of the IDUA gene, one 1.8-kb segment containing exons 1 and 2 and surrounding sequences and a second segment of 4.5 kb containing the last 12 exons. The potential promoter for IDUA has only GC box type consensus sequences consistent with a housekeeping promoter and is bounded by an Alu repeat sequence. The first two exons of IDUA are separated by an intron of 566 bp, then there is a large intron of approximately 13 kb, and the last 12 exons are clustered within 4.5 kb. No consensus polyadenylation signal was found in the 3′ untranslated region, although two variant polyadenylation signals are proposed.     

Further investigation on nuclear transplantation in different orders of teleost: the combination of the nucleus of Tilapia (Oreochromis nilotica) and the cytoplasm of Loach (Paramisgurnus dabryanus).

The nucleus of a blastula cell from Tilapia (Oreochromis nilotica, family Cichlidae, order Perciformes) was transplanted into an enucleated egg of Loach (Paramisgurnus dabryanus, family Cobitidae, order Cypriniformes). From among 3747 nucleo-cytoplasmic hybrid (NCH) eggs two NCH larval fish (0.05%) were obtained; one died on the 6th day and the other died on the 12th day after the operation. Morphological examinations showed that both NCH larval fish had developed normally with an opened mouth except they could not take food after complete utilization of their egg yolk on the 5th day of development. The possible mechanisms for obtaining such inter-order NCH larval fish are discussed. This is the first report indicating that inter-order NCH larval fish can be obtained in spite of their evolutionary divergence.     

外源蜕皮激素对蓖麻蚕蛹发育的效应

本文报道蓖麻蚕蛹在室温28℃下的卵巢发育过程,以及外源20-羟基蜕皮酮对蚕蛹发育的影响。正常蛹在任何发育期内注射20-羟基蜕皮酮后,全部仍羽化成蛾,但蛹期延长约1至4天。无脑蛹经注射后出现蛹——蛾的变态,发育情况因剂量而不同:注射0.1微克后约有半数蛹发育成蛾;注射2微克羽化率较高,卵巢管的发育也最好;4微克或更高的注射量能使全部蛹发育成蛾,但卵巢管多少有些不正常。注射量超过5微克时,蛾体较小,颜色浅黄,没有或只有很少的鳞片。蛹的发育天数随剂量的增大而减少。经外源20-羟基蜕皮酮处理后,无论是有脑蛾或是无脑蛾的卵粒都明显地比正常蛾的卵粒大。当超过一定的注射量时,注射量越大,蚕蛾的自动蜕壳能力越差。