毛喉鞘蕊花的化学成分研究

本文报导了,从产于滇东北的毛喉鞘蕊花(Coleus forskohlii Brig)的根茎中分离到四个二萜化合物,经光谱分析鉴定,其结构分别为1α,6β,7α-triacetyl-coleonol—B(1),I-acetyl—forskolin(2),coleonol-B(3),和deacetyl-forskolin(4)。化合物(1)和(2)是首次从该植物中分离到。     

应用纯化的重组Epstein-Barr病毒早期抗原建立检测鼻咽癌病人血清IgA/EA抗体的ELISA方法

利用凝胶和离子交换柱(Mono Q)两次层析,将大肠杆菌表达的EB病毒早期抗原P138片段多肽纯化。以此P138为抗原,增加鼠抗人IgA单克隆抗体以扩大IgA的反应,建立了三步ELISA法。用本法检查了100例鼻咽癌病人和63例正常人血清中抗EB病毒IgA/EA抗体,病人血清的阳性检出率为86％,正常人有3例阳性(4.7％)。此结果表明,三步ELISA法较常用的间接ELISA法(阳性检出率为71％)敏感。     

人参多肽基因的化学合成和克隆

 本文报道了具有降血糖作用的人参多肽基因的设计及用固相亚磷酰胺法的合成。再以质粒pUC19作为克隆载体,以大肠杆菌JM101为受体菌,克隆了人参多肽基因,并成功地获得了克隆菌株。     

Stabilization of a HemA-LacZ hybrid protein against proteolysis during carbon starvation in atp mutants of Salmonella typhimurium.

Transposon insertions that stabilize the beta-galactosidase activity of a HemA-LacZ hybrid protein following carbon starvation were mapped to the atp operon of Salmonella typhimurium. This effect is similar to that seen with nuo mutants defective in the energy-conserving type I NADH dehydrogenase. Insertions in several other genes, including such highly pleiotropic mutants as rpoS, polA, and hfq, were isolated with the same phenotypic screen, but they do not affect the beta-galactosidase activity of HemA-LacZ. All of these mutants act indirectly to alter the colony color of many different fusion strains on indicator plates.     

A Bacillus subtilis malate dehydrogenase gene.

A Bacillus subtilis gene for malate dehydrogenase (citH) was found downstream of genes for citrate synthase and isocitrate dehydrogenase. Disruption of citH caused partial auxotrophy for aspartate and a requirement for aspartate during sporulation. In the absence of aspartate, citH mutant cells were blocked at a late stage of spore formation.     

Comparison of fish assemblages among an artificial reef, a natural reef and a sandy-mud bottom site on the shelf off Iwate, northern Japan

Synopsis Fish assemblages at an artificial reef site, a natural reef site and a sandy-mud bottom site, on the shelf (depth 130 m) off Iwate Prefecture, northern Japan, were surveyed by using a bottom trammel net from May 1987 to March 1993. A total of 12 173 fishes of 48 species were recorded. Physiculus maximowiczi was dominant and comprised 69% of the total numerical abundance. Total fish number was lowest in March at all the 3 sites when P. maximowiczi migrated to deeper and warmer waters. Assemblage equitability and species diversity also varied seasonally in accordance with the abundance fluctuation of P. maximowiczi. P. maximowiczi, Alcichthys alcicornis and Hexagrammos otakii were more abundant at the artificial reef and natural reef sites, while Dexistes rikuzenius and Hemitripterus villosus were more abundant at the sandy-mud bottom site; total fish abundance was largest at the artificial reef site mainly due to the large number of P. maximowiczi. Species richness was similar among sites, but equitability, and consequently species diversity, was lowest at the artificial reef site. The main effect of the artificial reef seemed the attraction of P. maximowiczi from nearby bottoms, especially from natural rocky reefs; its large abundance determined the structure of the artificial reef fish community.     

Charactererization of novel non-toxic Bacillus thuringiensis isoloates from Korea

J.Y. ROH, H.W. PARK, B.R. JIN, H.S. KIM, Y.M. YU AND S.K. KANG. 1996. Four Bacillus thuringiensis isolates from soil samples produced parasporal inclusions which were non-toxic to insects. The isolates were named B. thuringiensis NTB-1, NTB-2, NTB-3 and NTB-4. The parasporal inclusions were shown to be ovoid by phase contrast and scanning electron microscopy. The serotypes of the four isolates were determined by agglutination using 33 antisera; NTB-1 and NTB-4 seemed to be subsp. isruelensis ,and NTB-2 seemed to be subsp. pondzcheriensis . NTB-3 did not react with the 33 antisera. However, comparison of parasporal protein and plasmid DNA patterns of the four isolates with those of 15 known non-toxic B. thuringiensis strains demonstrated that the four isolates are novel.     

Role of acetylation on metal induced precipitation of alginates

Acetylation dramatically effects both the solution properties and the metal induced precipitation of alginates. The presence of acetyl groups on both bacterial and seaweed alginate polymers marginally increased the weight average molecular weight (M_w) of each polymer by 7% and 11%, respectively. Acetylated bacterial alginate showed a significant increase in solution viscosity compared to its deacetylated counterpart. However microbial acetylation of seaweed alginate did not change its solution viscosity. Acetylation altered the calcium induced precipitation of both alginates. The presence of acetyl groups decreased the ability of each polymer to bind with calcium but increased their ability to bind with ferric Ion (Fe³⁺). By controlling the degree of acetylation on the alginate chains, it was possible to modify solution viscosity and cation induced precipitation of these polymers.