Production of leukotrienes and prostaglandins in the rat uterus during peri-implantation period

We have measured by radioimmunoassay the production of leukotrienes (LTC4 and LTB4) and prostaglandins (PGE2 and PGF2 alpha) in the rat uterus on Days 1 through 6 of pregnancy. The production is defined as the synthesis minus the degradation for a defined period. The production of LTC4 or LTB4 remained unaltered on days 1-3, but exhibited a marked increase on Day 4 showing a peak at noon. This was then followed by a sharp decline on Day-5 morning. A small but consistent peak in uterine LT production was also noticed on Day-5 noon prior to implantation and this was followed by a decline on Day-6 morning i.e. after initiation of implantation. The production profile of PGE2 and PGF2 alpha showed a striking resemblance to that of LTs; one exception being that maximal PG production was noticed on Day-4 morning and preceded the peak production of LTs. These vasoactive arachidonate derivatives reached their peak production rates at around the time when a surge in estrogen level is noticed in the uterus on Day 4. Implantation is a local proinflammatory type of reaction that is associated with increased uterine vascular permeability. Vascular changes in inflammatory reactions are provoked by two kinds of chemical mediators: vasodilators and agents that increase vascular permeability. PGs (especially of the E series) are known as vasodilators, while LTs and histamine mediate increases in vascular permeability. Therefore, an interaction between LTs, PGs, and histamine could be important for uterine preparation for implantation and/or implantation per se.     

Mutations around the NG59 lesion indicate an active association of polyoma virus middle-T antigen with pp60c-src is required for cell transformation.

The transforming activity of polyoma virus middle-T antigen is believed to be dependent on its ability to form a complex with the cellular tyrosine protein kinase, pp60c-src. This hypothesis is based on observations of mutants of middle-T which demonstrated a correlation between these two activities. To investigate further the significance of pp60c-src association in transformation by middle-T, a series of deletion and point mutants were constructed around the NG59 lesion since this region has been implicated in pp60c-src binding. Analysis of the middle-T variants revealed a complete correlation between the presence of associated activated pp60c-src and the ability to transform. Further, this ability of pp60c-src to associate with middle-T may depend on the presence of a beta-turn between amino acids 177 and 180. The results indicate the NG59 phenotype results from the introduction of an isoleucine residue between amino acids 177 and 178 rather than the transition mutation at 179. The mutant MG1 is a single point mutation (at residue 180) and represents the smallest change in the middle-T which abolishes both the transformating and kinase activity of middle-T. Taken together, the data suggest the region surrounding the NG59 lesion is involved in the formation of an active complex between middle-T and pp60c-src and strongly suggest that this association is an absolute requirement for polyoma virus-induced transformation.     

毛叶丁香罗勒精油的化学成分分析

西双版纳引种栽培的毛叶丁香罗勒精油用Finnigan-4510型毛细管色谱/质谱/计算机联用方法进行了化学成分分析,共分离了26个成分,鉴定了其中的16个成分,占全精油含量的98.5％。主要成分是:丁香酚(80.33％);罗勒烯(12.80％);β-毕橙茄烯(4.24％)。     

Purification and comparison of the structures of human liver acidic alpha-D-mannosidases A and B.

Human liver alpha-D-mannosidases A and B were purified 11 500-fold and 2000-fold respectively. Both showed microheterogeneity when analysed by isoelectric focusing. Alpha-D-Mannosidases A and B are immunologically identical but differ in their range of pI values, molecular masses, uptake into fibroblasts and subunit compositions. Alpha-D-Mannosidase A consists of equimolar proportions of subunits of molecular masses 62 kDa and 26 kDa, which are linked by disulphide bridges in the intact enzyme. Alpha-D-Mannosidase B also contains a small subunit, of molecular mass 26 kDa, and a variable mixture of larger subunits, of molecular masses 58 kDa and 62 kDa. The 62 kDa and 58 kDa subunits, but not the 26 kDa one, contain concanavalin A-recognizing glycans. The 58 kDa subunit has a lower pI, contains less high-mannose glycans but probably contains more mannose 6-phosphate than the 62 kDa subunit. It is postulated that the differences in structure and properties of alpha-D-mannosidases A and B are due to differences in the state of processing of the large subunit. This suggestion is consistent with a single locus on chromosome 19 for lysosomal alpha-D-mannosidase.     

Redistribution of cell surface transferrin receptors prior to their concentration in coated pits as revealed by immunoferritin labels

Summary Immunocytochemistry has been used to study distribution of cell surface transferrin receptors in erythroid, leukemic (K562) cells. The cells were fixed and labelled with monoclonal (OKT-9) anti-transferrin receptor antibodies; the antibody-labelled receptors were then detected by either immunofluoresceinor immunoferritin-antimouse-antibody conjugates. Typically, the immunoferritin labels were distributed diffusely at the non-coated regions of the cell surface as well as concentrated in the clathrincoated pits. To examine further this pattern of distribution, cells were labelled at 0° C and then warmed to 37° C for zero to 30 min prior to fixation. The majority of the immunoferritin labels were initially dispersed in small groups at the non-coated regions of the cell surface (mean = 6 immunoferritin labels/cluster), but larger groups were common subsequent to incubation at 37° C (mean = 13 immunoferritin labels/cluster). However, the size of immunoferritin labels in the coated pits was unchanged (mean = 12 immunoferritin labels/pit). Immunoferritin labels were typical in coated and uncoated vesicles l min after warming to 37° C, but common in endosomes, multivesicular bodies and lysosomes by 30 min. It appears that single cell-surface receptors form large aggregates prior to their concentration in coated pits. Coated vesicles, uncoated vesicles, and endosomal vacuoles may together form the non-lysosomal compartment where the internalized receptors might be dissociated from the ligands (antibodies).     

禄丰古猿化石产地沉积环境与埋藏学的初步研究

本文根据沉积物成因、古气候和古生物特征,把禄丰古猿化石产地新第三纪地层划分为晚中新世石灰坝组和早上新世庙山坡组。据岩性和岩相特征,可划分出五个不同的沉积阶段,每个阶段代表不同的沉积环境。古猿和其他脊椎动物化石主要埋在石灰坝组(四段)湖泊沼泽化沉积环境,次之为庙山坡组(五段)河流相沉积环境。     

Properties of purified enzymes induced by pathogenic drug-resistant mutants of herpes simplex virus. Evidence for virus variants expressing normal DNA polymerase and altered thymidine kinase

The DNA polymerases and thymidine kinases induced by three drug-resistant mutants of herpes simplex virus type 1 (S1, Tr7, and B3) and their common parent strain, SC16, have been purified and their properties compared. No significant differences were seen in the affinities of the polymerases for TTP and dGTP, or for the triphosphates of 9-(2-hydroxyethyloxymethyl)guanine (acyclovir) or (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVdU) (drugs used in their isolation). In contrast all three mutants induced abnormal thymidine kinases. Those induced by the acyclovir-resistant mutants, S1 and Tr7, showed reduced affinities for thymidine, acyclovir, and also BVdU. Thymidine kinase induced by the BVdU-resistant mutant B3 showed reduced affinity for BVdU, but its affinities for thymidine and acyclovir were similar to those of the wild type enzyme. Thus, it appears that these variants of herpes simplex virus express altered thymidine kinases with impaired ability to phosphorylate particular nucleoside analogue drugs and these characteristics probably account for the drug resistance of the viruses. This strategy for resistance is important as it may result in variants with undiminished pathogenicity.     

Rotational diffusion of TEMPONE in the cytoplasm of Chinese hamster lung cells.

The correlation time for rotational diffusion (tau R) of 2,2,6,6-tetramethyl-4-piperidone-N-oxide (TEMPONE) in Chinese hamster lung (V79) cells has been measured. For these cells in an isosmotic solution at 20 degrees C, tau R = 4.18 X 10(-11) s, approximately 3.6 times greater than tau R = 1.17 X 10(-11) s in water. The relationship between tau R and viscosity was investigated in a number of glycerol-water (0-50%) and sucrose-water (20-40%) solutions and a constant Stokes-Einstein volume of 44 A3 was found for TEMPONE in solutions of less than 20% glycerol and sucrose. This gives an average shear viscosity (for rotation of a small molecule) of 0.038 poise for the cytoplasm. When nonsecular terms were used in the calculation of tau R, the activation energies for rotation of TEMPONE in the above solutions correlated well with the activation energies for shear viscosity. The viscosity increases as the cell is shrunk in hypertonic solutions. It also increases with decreasing temperature with an activation energy of 3.7 kcal/mol, about the same as the activation energy for the viscosity of pure water. The rotational correlation times were carefully calculated considering inhomogeneous line broadening, non-Lorentzian line shapes, the need for accurate tensor values and nonsecular terms.     

Testosterone metabolism by cytochrome P-450 isozymes RLM3 and RLM5 and by microsomes. Metabolite identification

Testosterone metabolism by cytochrome P-450 isozymes RLM3 and RLM5 in a reconstituted system and by rat liver microsomes was examined. Eleven metabolites were detected. Two of these, found in spots 2 and 4 of a thin layer plate, were only formed by the rat liver microsomes and may represent reductive metabolites of testosterone. A number of monohydroxy metabolites were conclusively identified by gas chromatography-mass spectrometry. These include the 2-, 6 beta-, 7 alpha-, and 16 alpha-hydroxy isomers. Liver microsomes formed the 2 alpha- and 2 beta-epimers in a 1:2 ratio and both co-chromatographed with a third reduced metabolite in thin layer plate spot 4. In contrast with RLM5 about 90% of the 2-hydroxy isomer was the 2 alpha-epimer. RLM3 did not perform the 2-hydroxylation in detectable amounts. The 6 beta-isomer was a major metabolite of RLM3 and microsomes, but a minor product of metabolism by RLM5. In contrast, the 7 alpha-isomer was a minor metabolite of RLM3, was not formed by RLM5, and was a major microsomal metabolite. Hydroxylation at position 16 alpha was a major activity of RLM5 and the heterogeneous microsomal cytochromes, but with RLM3 it was a minor reaction. One new metabolite was found which appeared to be hydroxylated in the D-ring, had a mass spectrum different from both 16 alpha- and 16 beta-hydroxytestosterone, and was tentatively identified as a 15-hydroxy isomer. In agreement with the literature, androstene-3,17-dione was found to be an oxidative metabolite of testosterone by both microsomes and purified cytochrome P-450. It was a major metabolite of RLM5 but was not produced by RLM3. Studies with 18O2 and H218O conclusively show that oxidation of testosterone at C-17 does not involve transient incorporation of an oxygen atom in this position. A mechanism is suggested whereby cytochrome P-450 acts as a peroxidase in the formation of androstenedione.