Molecular cloning of an endoglucanase gene from an alkalophilic Bacillus sp. and its expression in Escherichia coli.

One of the cellulase genes from alkalophilic Bacillus sp. strain N-4 was cloned in pBR322. A recombinant plasmid, pYBC107, expressing carboxymethyl cellulase (CMCase) was isolated, and the size of the cloned HindIII fragment was found to be 5.5 kilobases. The restriction map of pYBC107 showed a different pattern from those of pNKI and pNKII (N. Sashihara, T. Kudo, and K. Horikoshi, J. Bacteriol. 158:503-506, 1984). When the HindIII fragment from pYBC107 was subcloned into pYEJ001, there was a 3.8-fold increase in CMCase activity over that observed with pYBC107. Plasmid pYBC108 constructed by treatment of pYBC107 with HindIII and EcoRI expressed the CMCase activity, although to a limited extent. To verify the originality of cloned pYBC107 from Bacillus sp., we analyzed the restriction digest by Southern blotting.     

Modification of an arginine residue essential for the activity of NAD-malic enzyme from Ascaris suum

Purified NAD-malic enzyme from Ascaris suum is rapidly inactivated by the arginine reagent, 2,3-butanedione, and this inactivation is facilitated by 30 mM borate. Determination of the inactivation rate as a function of butanedione concentration suggests a second-order process overall, which is first order in butanedione. A second-order rate constant of 0.6 M-1 s-1 at pH 9 is obtained for the butanedione reaction. The inactivation is reversed by removal of the excess reagent upon dialysis. The enzyme is protected against inactivation by saturating amounts of malate in the presence and absence of borate. The divalent metal Mg2+ affords protection in the presence of borate but has no effect in its absence. The nucleotide reactant NAD+ has no effect on the inactivation rate in either the presence or absence of borate. A dissociation constant of 24 mM is obtained for E:malate from the decrease in the inactivation rate as a function of malate concentration. An apparent Ki of 0.5 mM is obtained for oxalate (an inhibitor competitive vs malate) from E:Mg:oxalate while no significant binding is observed for oxalate using the butanedione modified enzyme. The pH dependence of the first-order rate of inactivation by butanedione gives a pKa of 9.4 +/- 0.1 for the residue(s) modified, and this pK is increased when NAD is bound. The arginine(s) modified is implicated in the binding of malate.     

Evidence that epidermal growth factor is present in swiftlet's (Collocalia) nest

1. An epidermal growth factor (EGF)-like activity was detected and partially purified from swiftlet's nest extract. 2. The partially purified EGF-like activity was able to (a) generate competitive binding curves parallel to the standard curves in radioreceptor assay and (b) stimulate thymidine incorporation in quiescent culture of 3T3 fibroblasts and the latter activity can be suppressed by mouse EGF antibody. 3. Partial characterization of the EGF-like activity in terms of pI, molecular weight and its behavior on gel filtration column suggest that it bears similar physical properties to the EGFs isolated from the mouse and the shrew.     

Inactivation of Giardia lamblia and Giardia canis cysts by combined and free chlorine

Free chlorine and a combined organic N-chloramine (3-chloro-4,4-dimethyl-2-oxazolidinone, compound 1) were compared for efficacy as disinfectants against an admixture of cysts of Giardia lamblia and Giardia canis in water solution under a variety of test conditions; variables were pH, temperature, and water quality. In general, compound 1 was found to reduce the giardial excystation in the solutions at lower concentration or shorter contact time at a given total chlorine concentration than did free chlorine.     

Applied anatomy of the anterolateral femoral flap

A study of the source of the blood supply to the anterolateral femoral flap was carried out on 42 lower limbs of adult cadavers (among them 35 cadavers with injection of red latex and 1 with india ink into the arteries and 6 vascular cast specimens), and the surface locations of the vascular pedicle were detected on 50 healthy adults. It was found that the descending branch of the lateral circumflex femoral vessel was an ideal axial vessel. There are constant perforating branches of the myocutaneous artery or cutaneous branches from the intermuscular space to the anterolateral femoral skin. The area extends about 12 x 30 cm. Within the flap, the anterior branch of the anterolateral cutaneous nerve of the high is located. This flap has been widely used for free transplantation in China since 1983 with satisfactory results.     

一个1B/1R小麦-黑麦染色体易位的鉴定

本研究对冬小麦品系73(36)9-1的1B/1R易位染色体进行了遗传分析。发现73(36)9-1有一对随体染色体,它的两个亲本矮丰四号及洛夫林10(Lovrin lo)分别有两对和一对随体染色体。观察用矮丰四号回交的F_1,绝大部分花粉母细胞的中期染色体都能正常配对,而用洛夫林10回交的,除了多数产生两个单价体之外,正常配对的情况也能经常看到。同时还发现,73(36)9-1和“中国春”双端体(CSDT)的1BL能很好地配对并形成一个棒状的异形二价体,而它和CSDT 1BS的染色体则主要产生20″+1′+t′的构型,从而证明易位发生在1B染色体的短臂,并且该易位的片段来自黑麦染色体1RL。本文还讨论了该易位发生的可能途径,推断是由于在F_1花粉母细胞中的两个单价体(一个是小麦染色体1B,一个是黑麦染色体1R)同时进行错分裂之后产生的两种端着丝点染色体(1BL和1RL)重新并合形成的,因而冬小麦73(36)9-1可能是一个自发产生的易位系。     

白毛新木姜子[Neolitsea aurata var.glauca]胚胎学研究

应用光学显微镜对白毛新木姜子的胚胎学特征进行了研究,首次在非寄生性樟科植物中发现了细胞型胚乳。对樟科8属进行了胚胎学特征的比较。花药四室,药室壁的发育属于"基本型",周原质团型绒毡层。小孢子母细胞连续型分裂。等四面体型四分体。二细胞成熟花粉,无孔沟。雌孢原多个,一般仅一个能继续发育。蓼型胚囊。助细胞具丝状器。反足细胞宿存。大孢子母细胞和合子具极性。宿存的一个助细胞具有吸器功能。细胞型胚乳,胚胎发育属于柳叶菜型的三叶变型。种皮源于外珠被,内表皮细胞壁螺旋状加厚。胚胎学特征表明,新木姜子属与木姜子属有密切的亲缘关系。较多的双胚囊异常现象,支持樟科与Monimiaceae具有紧密关系的推测。胚胎学特征不支持将无根藤属独立为科的观点。     

青海锡铁山矿区铅、锌的植物地球化学特征及其与矿的关系

 通过青海锡铁山铅、锌矿区植物群落和植物中铅,锌含量特征的调查研究表明：该区植被为荒漠植被类型。矿带上的植物群落与非矿带上的相比较,群落中种属数目更少,覆盖度更低,植物生长更低矮。植物灰分中的锌含量(平均)为125.9—1144ppm。膜果麻黄(Ephedra przewalskii)含量最高,变化范围最大,为86.11—5871.88ppm。植物中的铅含量为31.32—1129.6ppm。黑柴(Sympegma regelii)含量较高,变化最大,平均为746ppm,极值为14.3—5561.70ppm。在矿带上含量最高,非矿带对照区含量最低。植物及其生长的土壤中金属元素含量之间的关系,无论是铅还是锌含量都有很好的线性关系。膜果麻黄、黑柴、优若藜(Eurotia ceratoides)和中亚紫菀木(Asterothamnus centrali-asiaticus)等植物相关系数均达显著相关水平(α≤0.05)。 这在植物地球化学勘探上是非常有用的。例如中亚紫菀木和琵琶柴(Reaumuria soongorica)中铅的植物地球化学异常,准确地圈出了铅、锌矿的位置,衬度高,异常范围与矿化区基本吻合。     

Metacercarial infections of Paragonimus westermani in freshwater crabs sold in markets in Seoul

Status of metacercarial infections of Paragonimus westermani was observed in freshwater crabs, which were purchased at 3 markets in its peak season of 1990. All of 85 crabs were Eriocheir japonicus. No other species of Eriocheir were found. When crushed muscle and viscera was examined individually, the infection rate was 11.8%; and mean number of metacercariae was 2.1 per infected crab. Unless adequately cooked, freshwater crabs are still potential sources of human paragonimiasis.     

Component proteins in crude extract of adult Paragonimus westermani purified by immunoaffinity chromatography using monoclonal antibodies.

The nature of 2 component proteins in crude saline extract of adult Paragonimus westermani was investigated. By immunoaffinity chromatography using monoclonal antibodies (MAb) as ligands, the proteins were purified from the crude extract. Band 1 protein in disc-polyacrylamide gel electrophoresis (PAGE) was purified by PFCK-136 MAb. The protein, known to have molecular mass of 440 kDa, was composed of 23, 46 and 92 kDa subunits when observed by reducing SDS-PAGE and SDS-PAGE/immunoblot. This protein was originated from eggs of the worm as revealed by immunohistochemical staining with PFCK-136 Mab. Another affinity purified protein utilizing PFCK-44 MAb was the band 4 protein of 17 kDa in disc-PAGE. This was a monomer protein in reducing SDS-PAGE and SDS-PAGE/immunoblot. The protein was produced at intestinal epithelium of the worm.