Effects of dimethylsulfoxide on the ultrastructure of fixed cells

It has been reported that the use of dimethylsulfoxide (DMSO) as a solvent for fixatives enhances preservation of cellular ultrastructure. By contrast, we have shown that DMSO alters the ultrastructural integrity of glutaraldehyde fixed cells. The cell membrane, nuclear envelope, endoplasmic reticulum, ribosomes, microtubules and intracytoplasmic organelles are most susceptible to the action of DMSO. We hypothesize that DMSO exerts intracellular alterations via its interaction with remnant interfacial water in fixed cells. DMSO-induced alterations of these and related cellular components may result in the formation of artefactual structures and networks. Thus, it appears that DMSO containing glutaraldehyde neither accelerates fixation nor enhances stabilization of cellular ultrastructure. For these reasons, addition of DMSO to fixatives is not recommended.     

应用RNA干扰技术调节大鼠c-jun基因的表达

目的:应用RNA干扰(RNAi)技术调节大鼠c-jun基因在Cos-7细胞中的表达.方法:分别构建大鼠c-jun基因的RNA干扰载体和真核表达GFP(绿色荧光蛋白)载体,将两者共转染Cos-7细胞,镜下观察大鼠C-Jun-GFP融合蛋白的表达,应用Western blot方法检测抑制效率.结果:酶切和测序结果表明,大鼠c-jun基因的RNA干扰载体和真核表达GFP载体构建成功,镜下及Western blot共转染结果均显示随着RNA干扰载体浓度的增加C-Jun-GFP融合蛋白表达量逐渐减少.结论:在Cos-7细胞中应用RNAi技术成功调节大鼠c-jun基因的表达.     

The Synthesis and Antiherpetic Activity of Acyclovir Phosphonate Esters

Alkyl esters of acyclovir phosphite, alkoxycarbonylphosphonate, ethoxycarbonylmethylphosphonate, and aminocarbonylphosphonate were synthesized. Most of them were shown to inhibit the replication of type 1 herpes simplex virus in Vero cell culture. The stability in phosphate buffer and human blood serum was studied for several of the derivatives. A correlation between the stability and antiviral activity of the synthesized compounds is discussed.     

拟巫山淫羊藿的megastigmane糖苷和苯丙醇类成分

为了解拟巫山淫羊藿(Epimedium pseudowushaneseB. L. Guo)的化学成分,其从地上部分水提物中分离得到2个megastigmane糖苷和4个苯丙醇类化合物。通过波谱分析,分别鉴定为淫羊藿次苷B6(1)、megastigman-5-ene-3,9-diol 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (2)、丁香酚芸香糖苷(3)、2-羟基-1-(4-羟基-3,5-二甲氧基苯基)-1-丙酮(4)、2,3-二羟基-1-(4-羟基-3,5-二甲氧基苯基)-1-丙酮(5)、2,3-二羟基-1-(4-羟基-3-甲氧基苯基)-1-丙酮(6)、二氢松柏基醇γ-O-α-L-鼠李糖苷(7)。其中化合物2和7为新化合物,所有化合物均为首次从拟巫山淫羊藿中分离得到。     

Dexamethasone treatment in vitro resulted in different responses of two fractions of phagocytes of the holothurian Eupentacta fraudatrix

Echinoderm phagocytes are considered to be analogues to vertebrate macrophages. Previously, the phagocytes of some echinoderm species were divided into two fractions with unclearly identified functional properties. This study aims at modeling the immune response of two phagocyte fractions (P1 and P2) of the holothurian Eupentacta fraudatrix to the synthetic glucocorticoid hormone dexamethasone (Dex) in vitro and at comparison of the effects of such pretreatment on humoral cooperation of each phagocyte fraction with another type of immunocytes, morula cells. During 48-h incubation, Dex (0.1–100 μM) induced apoptosis in a direct (in the P1 fraction) or reverse (in the P2 fraction) concentration-dependent manner. In addition, 100 μM Dex differently affected the cytokin-like substance level in the P1 and P2 phagocyte fractions. Moreover, the supernatants of the Dex(100 μM)-pretreated phagocytes induced opposite changes in the IL-1-like substance level in morula cells. These results indicate a striking functional difference between the two phagocyte fractions. The data obtained provide a new insight into the evolution of macrophage response and into the prospects of the use of in vitro holothurian phagocyte model.     

Fluorescence parameters of marine plankton algae at the assimilation of organic nitrogen

fluorescence parameters of marine plankton algae Pseudo-nitzschis delicatissima, Thalassiosira weissflogii, and Tetraselmis viridis were estimated after the addition of organic (urea and glycine) and inorganic (nitrate and ammonia) nitrogen to nitrogen-limited cultures acclimated to limited and saturated irradiance. The photochemical efficiency of photosystem 2, the maximum relative electron transport, and the light saturation index increased in the algae assimilating organic nitrogen. The dynamics of parameters depended species specifically on the nitrogen source and irradiance. The ecological role of organic nitrogen in the seasonal dynamics and vertical distribution of phytoplankton is discussed.     

Use of recombinant HBcore antigen for development of the diagnostic test-system

The plasmid construction expressing recombinant HBc antigen (HbcAg) in Escherichia coli cells under the control of the PL promoter of phage I, was obtained. The specific activity of the antigen thus obtained was controlled by the enzyme immunoassay (EIA) method and compared with the reference system "AxSYM CORE assay" ("Abbott", USA) with four panels of sera (altogether 111 samples). The coincidence of the results of the compared test system with the reference was 96.4%, which made it possible to recommend this genetic construction of recombinant HBcAg for the production of EIA systems.