Construction and packaging of pseudotype retrovirus containing human N—ras cDNA antisense sequence and its biological effects on human hepatoma cells

N-ras is one of the transforming genes in human hepatic cancer cells.It has been found that N-ras was overexpressed at the mRNA and protein level in hepatoma cells.In order to explore the biological roles of N-ras in human hepatic carcinogenesis and the potential application in control of cancer cell growth,a preudotype retrovirus containing antisense sequence of human N-ras was constructed and packaged.A recombinant retrovirus vector containing antisense or sense sequences of N-ras cDNA was constructed by pZIP-NeoSV(X)1.The pseudotype virus was packaged ang rescued by transfection and infection in PA317 and ψ 2 helper cells.It has been demonstrated that the pseudotype retrovirus containing antisense N-ras sequence did inhibit the growth of human PLC/PRF/5 hepatoma cells accompanied with inhibition of p21 expression,while the retrovirus containing sense sequence had none.The pseudotype virus had no effect on human diploid fibroblasts.     

吉林省寄螨亚科三新种(啤螨目:寄螨科)

本文记述寄螨亚科(Parasitinae)三新种。模式标本保存于吉林省地方病第一防治研究所。文内测量单位为微米,括号内为测量平均值。     

腐霉属分类性状评价及其中国的种

本文对腐霉属Pythium Pringsheim的研究历史作了简单的回顾,对该属的分类性状和系统进行了论述和评价,最后对中国已发现的55种腐霉,以检索表的方式进行了分类、检索。     

Kinetics of excited states of pigment clusters in solubilized light-harvesting complex II: photon density-dependent fluorescence yield and transmittance.

Relative fluorescence yield, phi F, and transmittance, T, were measured in solubilized light-harvesting complex II (LHCII) as a function of photon density, Ip, of monochromatic 645-nm laser pulses (duration: approximately 2.5 ns). Special efforts were made in constructing an optical set-up that allows the accurate determination of the fluorescence from an area of constant Ip, phi F(Ip) starts to decline at approximately 10(14) and drops to values below 0.01% at maximum Ip (approximately 10(19) photons cm-2 pulse-1). T(Ip) decreases only slightly at photon densities of approximately 10(15) but increases steeply at values of > 10(17) photons cm-2 pulse-1. The interpretation of the phi F(Ip) data using the saturation limit of Mauzerall's multiple hit model leads to a unit size of about 10-15 chlorophyll molecules. One interpretation is to attribute this result to a very fast exciton-exciton annihilation of multiple excited states generated within this small domain. Alternatively, based on the assumption that delocalized cluster states within the monomeric/trimeric subunit of LHCII exist, the results can be consistently described by a kinetic model comprising ground, monoexcitonic, and biexcitonic states of clusters and a triplet state that is quenched by carotenoids in LHCII. Within the framework of this model the annihilation of multiple excitations is explained as ultrafast radiationless relaxation of higher excited cluster states. Comparative measurements in diluted acetonic Chl a solution are consistently described by the depletion of the ground state, taking the absorption cross section at the used wavelength.     

Keratella distribution in North Patagonian lakes (Argentina)

The distribution of Keratella species from 15 different lakes in North Patagonia (Argentina) was analysed. The genus was not present at altitudes above 1000 m. K. tropica was restricted to Patagonian Plateau lakes with a comparatively high conductivity. A morphometric analysis of the widely distributed K. cochlearis was performed. Results showed three groups of K. cochlearis corresponding to Andean lakes, Patagonian Plateau lakes and a Patagonian Reservoir.     

Deep-level diagnostic value of the rDNA-ITS region

The similarity of certain reported angiosperm rDNA internal transcribed spacer (ITS) region sequences to those of green algae prompted our analysis of the deep-level phylogenetic signal in the highly conserved but short 5.8S and hypervariable ITS2 sequences. We found that 5.8S sequences yield phylogenetic trees similar to but less well supported than those generated by a ca. 10-fold longer alignment from rDNA-18S sequences, as well as independent evidence. We attribute this result to our finding that, compared to 18S, the 5.8S has a higher proportion of sites subject to vary and greater among-site substitution rate homogeneity. We also determined that our phylogenetic results are not likely affected by intramolecular compensatory mutation to maintain RNA secondary structure nor by evident systematic biases in base composition. Despite historical homology, there appears to be no ITS2 primary sequence similarity shared sufficient similarity to cluster correctly on the basis of alignability. Our results indicate that groups, however, share sufficient similarity to cluster correctly on the basis of alignability. Our results indicate that ITS region sequences can diagnose organismal origins and phylogenetic relationships at many phylogenetic levels and provide a useful paradigm for molecular evolutionary study.      

Influences on the antimicrobial activity of surface-adsorbed nisin

The efficacy of the antimicrobial peptide nisin was examined after adsorption to silica surfaces. Three protocols were used to evaluate nisin's activity against adhered cells ofListeria monocytogenes: bioassay usingPediococcus pentosaceous FBB 61-2 as the sensitive indicator strain; visualization and enumeration of cells by microscopic image analysis; and viability of adhered cells as determined by lodonitrotetrazolium violet uptake and crystallization. The activity of adsorbed nisin was highly dependent upon conditions of adsorption. The highest antimicrobial activity of adsorbed nisin occurred with high concentrations of nisin (1.0 mg ml^–1) and brief contact times (1 h) on surfaces of low hydrophobicity. Sequential adsorption of a second protein (-lactoglobulin or bovine serum albumin) onto surfaces consistently resulted in decreased nisin activity. These data provide direction for the development of applications to limit microbial attachment on food contact surfaces through the use of adsorbed antimicrobial peptides.     

山西雏蝗属二新种：直翅目：网翅蝗科

本文记述山西省雁北地区雏蝗属Ｃｈｏｒｔｈｉｐｕｓ Ｆｉｅｂｅｒ１８５２二新种,即郑氏雏蝗Ｃｈｏｒｔｈｉｐｐｕｓ ｚｈｅｎｇｉ,ｓｐ．ｎｏｖ．和宽带雏蝗Ｃｈｏｒｔｈｉｐｐｕｓ ａｍｐｌｉｌｉｎｅａｔｕｓ,ｓｐ．ｎｏｖ。模式标本保存在山西省农牧厅植保植检总结。     

简便、快速提取高质量的RNA分子

MethodsforHandy,RapidIsolationofHighQualityRNAbyGuanadiumThioeyauateDuJianYuanYanhuaMaShenglinDongZhiwei(BeijingInstituteforCancerResearchBeijing100034)硫氰胍是一种有效的蛋白变性剂。早在1979年,Chirgwin等就利用氯化铯／硫氰胍超离心技术成功地从RNA酶富集的胰脏组织中提取出未降解的RNA分子[2],从而使它成为抑制RNA酶的首选药物并得到广泛使用,但受到超速离心设备的限制。1983年,Cathala报道了氯化锂／硫氰胍RNA提取法[1]。该方法操作简便,获得的RNA质量很高,但所需时间较长。为了能在短时间内更快…