IL－6受体结构与功能的研究进展

ＩＬ－６是一个多功能的细胞因子,其生物学作用在很大程度上受ＩＬ－６受体（ＩＬ－６Ｒ）结构和功能的影响。ＩＬ－６Ｒ由两条多肽链组成,即配体结合链ｇｐ８０和信号传导链ｇｐ１３０。它们在结构和功能上既有分工又有合作。两种亚基组成的高和力ＩＬ－６Ｒ是介导细胞效应所必需的。ＩＬ－６Ｒα中的造血功能区属于造血因子受体超家族成员,它决定着结合ＩＬ－６的能力,然而ｇｐ１３０则是多种细胞因子共用的信号传递分子,其胞     

Zeta potential of protoplasts from gravireacting maize roots

Protoplasts were isolated from cortical cells of the elongating zone of maize (Zea mays L. cv. LG 11) roots and submitted to microelectrophoresis. Significant and transient differences in zeta potential between protoplasts from upper and lower root sides were compared with the gravireaction and the differential elongation of these roots. The maximum difference in the zeta potential was obtained between protoplasts from the upper and lower cortical cells after 90 min, exactly the time of gravipresentation for which the maximum rate of gravireaction was observed. In addition, this almost corresponded to the time for which the difference between the elongation rates of upper and lower sides of the extending zone began to increase. Consequently, the changes in the charges of the plasmalemma of the cortical cells from the growing part of roots could be more or less directly related to the root graviresponse.     

Very long chain fatty acids: Occurrence and biosynthesis in membrane fractions from etiolated maize coleoptiles

The endoplasmic reticulum from maize coleoptiles elongates stearoyl-CoA more effectively than the plasmalemma-enriched fraction. The alkane and very lo     

Sialyl-transferase mitochondriale

A sialyl transferase activity is found in purified mitochondria. It is not due to residual contamination and this enzymatic system is located in the outer mitochondrial membrane. This proves mitochondrial autonomy in regard to glycoconjugate sialylation.     

Dehalogenation of dichloromethane by cell extracts of hyphomicrobium DM2

A facultatively methylotrophic bacterium was isolated from enrichment cultures containing dichloromethane as the sole carbon source. It was identified as a Hyphomicrobium species. The organism grew exponentially in batch cultures with 10 mM dichloromethane at a specific growth rate of 0.07 h^-1. The release of Cl^- from dichloromethane and the disapperance of substrate paralleled growth. Resting dichloromethane-grown cells, in the presence of potassium sulphite as a trapping agent, converted cichloromethane methane quantitatively to formaldehyde. The conversion of dichloromethane to formaldehyde by cell extracts was stricly dependent on glutathione. Other thiols were inactive. Glutathione was not consumed in the course of the reaction. The specific activity of the enzymic dehalogenation of dichloromethane amounted to 3.8 mkat/kg protein in extracts of dichloromethane-grown cells and to less than 0.1 mkat/kg protein in extracts from cells grown on methanol.     

Determination of rat muscles androgen-receptor complexes with methyltrienolone

In the present study, “in vitro” evidences are shown for the existence of a highly active 3α-hydroxysteroid dehydrogenase in the crude cytosol of rat muscle homogenates; the use of 5α-dihydrotestosterone (DHT) is therefore compromised in receptor binding measurements because of its extensive metabolism. The synthetic anabolic androgen, methyltrienolone (MT) palliates this disadvantage of DHT. Both steroids, as well as testosterone, appear to be bound to an 8–8.5 S androgen receptor on sucrose density gradient. The androgen receptor in the vastus and the levator ani bulbocavernosus complex (LA/BC) shows similar association constants, but the number of binding sites in LA/BC is about 5 times higher than in vastus. Otherwise, the total number of muscle androgen receptors seems to be invariant in adult and aged rats. The binding to these macromolecules can thus be measured “in vitro” provided specific and sensitive methods are utilized.     

Computation of the fraction of induced cells in enzyme induction systems

A theoretical model is developed for continuous multistage enzyme production systems, which consist of a growth fermentor used for growing microorganisms rapidly without enzyme production and a subsequent system of induction reactors in which enzymes induction and production occurs. The model allows the computation of the fraction of induced cells residing in the induction reactor for organisms exhibiting a lag phase in enzyme induction. For this model a general analytical solution was obtained for the cumulative internal residence time distribution of a series of n well-stirred vessels with a recycle. The theoretical results are compared in a preliminary way with experimentally measured cellulase productivities of continuous multistage cellulose fermentations with Trichoderma viride QM 9414.