The H-2KbtsA58 transgenic mouse: A new tool for the rapid generation of novel cell lines

The ability to generate expanded populations of individual cell types able to undergo normal differentiationin vitro andin vivo is of critical importance in the investigation of the mechanisms that underly differentiation and in studies on the use of cell transplantation to repair damaged tissues. This review discusses the development of a strain of transgenic mice that allows the direct derivation of conditionally immortal cell lines from a variety of tissues, simply by dissociation of the tissue of interest and growth of cells in appropriate conditions. In these mice the tsA58 mutant of SV40 large T antigen is controlled by the interferon-inducible Class I antigen promoter. Cells can be grown for extended periodsin vitro simply by growing them at 33°C in the presence of interferon, while still retaining the capacity to undergo normal differentiationin vivo andin vitro. In addition, it appears that cell lines expressing mutant phenotypes can readily be generated by preparing cultures from appropriate offspring of matings between H-2K^btsA58 transgenic mice and mutant mice of interest.     

Influence of amylose,amylopectin and pullulan on β-glucuronidase activity of starch-degrading Escherichia coli

Synthesis of 58hkl1204862/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-glucuronidase in starch-degrading Escherichia coli (S1) was induced by amylose, amylopectin and pullulan supplied in mineral medium as the sole carbon source (1%, w/v). The maximum activity occurred after 4 days when cultures reached the stationary phase of growth, but induction was also evident during log-phase. The effects obtained with amylose, amylopectin and pullulan were higher than that obtained with maize starch.     

Global dynamics of a ratio-dependent predator-prey system

Recently, ratio-dependent predator-prey systems have been regarded by some researchers to be more appropriate for predator-prey interactions where predation involves serious searching processes. However, such models have set up a challenging issue regarding their dynamics near the origin since these models are not well-defined there. In this paper, the qualitative behavior of a class of ratio-dependent predator-prey system at the origin in the interior of the first quadrant is studied. It is shown that the origin is indeed a critical point of higher order. There can exist numerous kinds of topological structures in a neighborhood of the origin including the parabolic orbits, the elliptic orbits, the hyperbolic orbits, and any combination of them. These structures have important implications for the global behavior of the model. Global qualitative analysis of the model depending on all parameters is carried out, and conditions of existence and non-existence of limit cycles for the model are given. Computer simulations are presented to illustrate the conclusions.     

HUMAN B CELL DIFFERENTIATION: DEPENDENCE ON INTERACTIONS WITH MONOCYTES AND T LYMPHOCYTES VIA CD40, CD80 (B7.1), AND THE CD2-LIGANDS CD48 AND CD58 (LFA-3)

B cell differentiation depends on cellular interactions with T lymphocytes and monocytes via adhesion molecules (AM). In order to characterize AM which are required for B cell differentiation immunoglobulin production using unseparated peripheral blood mononuclear cells (PBMC) was studied. Unstimulated human PBMC were cultured for 9 days with mAb directed at CD2/CD48, /CD58, CD59, CD5/CD72, CD11a—CD18/CD54, CD28/CD80, CD86, CD40/CD40L, or rat CD2 (control). B cell differentiation was quantified measuring IgM and in some cases IgA, IgG, and IgE production. IgM levels were significantly reduced by mAb against CD40, CD48, CD58 and CD80. The reduction was not due to isotype switching to IgA, IgG or IgE. The role of CD40, CD48, CD58 and CD80 was further investigated after depletion of different cell types. Depletion of monocytes and NK cells resulted in no detectable IgM production irrespective of added mAbs. In contrast, IgM production was still present after depletion of T cells and NK cells. Only mAb against CD80 and CD48 significantly reduced IgM production, the reduction of IgM production by anti-CD40 mAb was less than in the presence of T cells. Importantly, anti-CD58 mAb had no effect on IgM production after T cell and NK cell depletion. Taken together, the AM CD40, CD48, CD58, and CD80 are involved in Ig production of unseparated PBMCs. In this model of B cell differentiation only the AM CD58 depend on the presence of T cells while CD48 and CD80 help was found to be T cell independent.     

Effect of a swim training on homocysteine and cysteine levels in rats

Summary. The purpose of this study was to investigate the effects of a 8-week of swim training on total plasma homocysteine and cysteine levels in 16 male Sprague-Dawley rats aged 17 weeks. We also evaluated the activity of hepatic cystathionine 58qt0mkfq5rfdj1/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-synthase (CBS), an enzyme involved in the metabolism of Hcy, the concentration of plasma glutathione, taurine, and a fraction of vitamin B6: the pyridoxal 5-phosphate (PLP). After one week of acclimatization, rats were randomly divided into two groups: 8 non-trained (NTR) and 8 trained rats (TR). Following the training period, body weight gain was lower in TR than in NTR. Plasma homocysteine did not differ among groups while significantly lower plasma cysteine and taurine levels were found in TR (157.83±8.658qt0mkfq5rfdj1/xxlarge8201.gif" alt="thinsp" align="MIDDLE" BORDER="0">58qt0mkfq5rfdj1/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">mol/L; 133.01±9.3258qt0mkfq5rfdj1/xxlarge8201.gif" alt="thinsp" align="MIDDLE" BORDER="0">58qt0mkfq5rfdj1/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">mol/L; P<0.05) compared with data of NTR (176.19±4.958qt0mkfq5rfdj1/xxlarge8201.gif" alt="thinsp" align="MIDDLE" BORDER="0">58qt0mkfq5rfdj1/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">mol/L; 162.57±8.1658qt0mkfq5rfdj1/xxlarge8201.gif" alt="thinsp" align="MIDDLE" BORDER="0">58qt0mkfq5rfdj1/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">mol/L; P<0.05). No significant changes in hepatic CBS activity were observed in TR compared with NTR. Moreover, values for plasma glutathione and PLP concentrations were not affected by training.These results indicate that training reduces plasma cysteine and taurine levels whereas it does not modify other studied parameters. Thus, physical training may regulate cysteine metabolism.     

Selectivity of the excision of alkylation products in a xeroderma pigmentosum-derived lymphoblastoid line.

Lymphoblastoid cell derived from a complementation group C xeroderma patient were unable to remove 06-methyl guanine residues formed in DNA by treatment of cells with low concentration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). The xeroderma cells were competent in their ability to excise 3-methyl adenine adducts. MNNG treatment induced excision repair in the xeroderma line and in addition the treatment resulted in the presence of numerous single-strand breaks in the DNA. The single gene, UV-excision-defective mutants of Escherichia coli, uvrA and uvrB, are able to excise MNNG-induced 06-methyl guanine adducts indicating that excision of this compound is not due to operation of UV endonuclease system.     

比较基因识别-58

比较基因识别-58（comparative gene identification-58,CGI-58）属于脂肪酶家族,是脂肪性甘油三酯脂肪酶的激活蛋白,在调控脂肪代谢方面发挥着至关重要的作用,也是调控角质形成细胞的分化过程的重要分子。另外,CGI-58还具有溶血磷脂酸酰基转移酶活性,可将溶血磷脂酸酰化成磷脂酸。若CGI-58的基因发生突变,会引发一种隐性遗传的中性脂肪蓄积病——Chanarin—Dorfman综合征（Chanarin-Dorfman symptom,CDS）,病体表现出鱼鳞病。本文将针对CGI-58调控脂肪代谢以及其它方面的功能,对近些年来CGI-58的研究进展进行综述。     

Catalysts for the self-polymerization of adenosine cyclic 2′,3′-phosphate

Summary When adenosine cyclic 258v03t608672l6h/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">,358v03t608672l6h/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-phosphate is evaporated from solution in the presence of simple catalysts such as aliphatic diamines at alkaline pH, and maintained in a dry state at moderate temperatures (25-85°C), self-polymerization to give oligonucleotides of chainlength up to at least 6 is observed. The products contain an excess of [358v03t608672l6h/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">58v03t608672l6h/xxlarge8594.gif" alt="rarr" align="BASELINE" BORDER="0">558v03t608672l6h/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">]-linkages over [258v03t608672l6h/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">58v03t608672l6h/xxlarge8594.gif" alt="rarr" align="BASELINE" BORDER="0">558v03t608672l6h/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">]-linkages. The effects of different catalysts and reaction conditions on the efficiency of the reaction are described. The prebiological relevance of these reactions is discussed.     

RSSG58基因在水稻精细胞中的表达

RSSG5 8是利用抑制差减杂交技术从水稻精细胞文库中筛选到的在精细胞中优势表达的基因 ,推测其编码的蛋白质与拟南芥的肌球重链蛋白有一定的同源性 (4 6 % ) ,并具有肌球蛋白特色的结构域。把RSSG5 8基因开放编码框连接到表达载体pQE30上 ,重组质粒在E .coliM15中表达出N端融合了 6×His的融合蛋白。SDS PAGE分析表明 ,表达产物的分子量约为 6 6kD ,其表达量占菌体总蛋白的 8.6 %。分离纯化融合蛋白来免疫家兔 ,制得了高效价、高特异性的多克隆抗体。Western杂交显示 ,在分离的精细胞内该基因编码的蛋白表达量很高 ,而成熟花粉和二细胞中只有微弱表达 ,单细胞花粉、花粉母细胞没有杂交信号 ,表明RSSG5 8基因在精细胞中优势表达。