Oxidative stress in mice

The aim of this study was to analyze the effect of high dietary Fe on liver antioxidant status in mice fed a corn-oil-enriched diet. Male Balb/c mice were fed for 3 wk with a standard diet enriched with 5% by weight of corn oil with adequate Fe (FCO diet) or supplemented with 1% carbonyl Fe (FCOFe diet). The control group was fed a standard diet. The high-Fe diet induced a twofold increase of hepatic Fe level. However, an increase of thymic Fe level has been induced solely by dietary fat. The hepatic copper (Cu) level slightly decreased in the FCO diet. In the spleen, the high-Fe diet-induced increase of Fe level was negatively correlated with the Cu level. The antioxidant status was influenced by both dietary fat and Fe. Mice fed corn-oil-enriched diets had a higher concentration of thiobarbituric acid-reactive substances (TBARS), with a greater increase in the FCOFe diet. Fatty acid analysis showed decreased n−3 and n−6/n−3 ratio, particularly in the FCOFe diet. Hepatic Cu/Zn superoxide dismutase (CuZn-SOD) activity was decreased in FCO diet, and Fe supplementation caused a further decrease in the enzyme activity. These results suggest that feeding with corn oil-enriched diet increases oxidative damage by decreasing antioxidant enzyme defense. The high-Fe diet additionally affects the antioxidant defense system, further increasing the tissue's susceptibility to lipid peroxidation. Additionally, both corn-oil- and Fe-enriched diets have increased the Cu requirement in mice.     

Endogenous ADP-ribosylation for eukaryotic elongation factor 2: evidence of two different sites and reactions

Eukaryotic elongation factor 2 can undergo ADP-ribosylation in the absence of diphtheria toxin under the action of an endogenous transferase. The investigation which aimed to gain insight into the nature of endogenous ADP-ribosylation revealed that this reaction may be, in some cases, due to covalent binding of free ADP-ribose to elongation factor 2. Binding of free ADP-ribose, and NAD- and endogenous transferase-dependent ADP-ribosylation were suggested to be distinct reactions by different findings. Free ADP-ribose could bind to elongation factor 2 previously subjected to ADP-ribosylation by diphtheria toxin or endogenous transferase. The binding of free ADP-ribose was inhibited by neutral NH2OH, L-lysine and picrylsulfonate, whereas endogenous ADP-ribosyltransferase was inhibited by NAD glycohydrolase inhibitors and L-arginine. The ADP-ribosyl-elongation factor 2 adduct which formed upon binding of free ADP-ribose was resistant to neutral NH2OH, but decomposed almost completely upon treatment with NaOH. The product of endogenous transferase-dependent ADP- ribosylation was partially resistant to NH2OH and NaOH treatment. Moreover, this reaction was reversed in the presence of diphtheria toxin and nicotinamide. Both types of endogenous ADP-ribosylation gave rise to inhibition of polyphenylalanine synthesis. This study thus provides evidence for the presence of two different types of endogenous ADP-ribosylation of eukaryotic elongation factor 2. The respective sites involved in these reactions are distinct from one another as well as from diphthamide, the site of attack by diphtheria toxin.     

烯效唑浸种对玉米幼苗生长和内源激素含量的影响

烯效唑浸种对玉米苗期叶片和叶鞘伸长生长有抑制作用,且抑制效应随烯效唑浓度的增大而增强,但植株粗壮,叶宽和茎基宽增加,根系增多,根长增加.烯效唑浸种的玉米幼苗中LAA和GA3含量下降,叶鞘中尤为明显;ZT含量则是地上部提高,根中下降,ABA含量提高,植株各器官中(IAA GA3)/ABA比值均下降,IAA/GA3比值均升高,IAA/ZT和GA3/ZT比值则是地上部降低,根中升高.     

海洋细菌活性物质的研究进展

由于海洋细菌有产生多种新颖独特的生物活性物质的巨大潜力,使其成为新药筛选的重要资源,在药品开发研究中具有良好的发展前景。综述了海洋细菌中具有药物开发前景的活性物质的研究和应用现状及其存在的问题。     

海绵动物原始神经物质的探究

本文以安徽芜湖淡水针海绵(Spongilla lacustrisLinnaeus)以及青岛海边海水海绵(Halichondria pan-icea)为研究对象,运用常规组织学、免疫组织化学、蛋白质免疫印迹等多种实验技术和方法,对海绵动物组织内的神经肽类(Neuropeptide Y,NPY;β-endorphin,β-EP)、神经纤维骨架类(S-100;Nervous specific enolase,NSE)、以及神经递质类(5-hydro-xytryptamine,5-HT)物质进行了研究。结果证实海绵动物体内存在神经类物质;对其分布进行了初步的定位;同时证实在海绵动物中存在原始的神经细胞。根据以上实验结果,推断海绵动物是介于原生动物和腔肠动物之间的过渡动物,在进化上占有不可取代的地位。     

鸡内源性类J亚群禽白血病病毒gp85基因的克隆及分析

为深入探讨J亚群禽白血病病毒(Avian leukosis virus subgroup J,ALV-J)的亚群特性,利用ALV-J gp85基因两侧的序列片段为引物,从正常SPF蛋鸡、商品肉鸡和DF1细胞基因组中完整地扩增了内源性类ALV-J gp85基因。肉鸡和DF1细胞内源性类ALV-J gp85基因同源性达99．9％;SPF蛋鸡内源性类ALV-J gp85基因与肉鸡和DF1细胞的内源性类ALV-J gp85基因之间同源性达95．6％、95．3％。三种不同来源的内源性类ALV-J gp85基因DNA与IMC10200株ALV-J的gp85基因的同源性分别为91．8％、94．1％、94．0％;与ALV-J原型株HPRS-103gp85基因的同源性分别为95．6％、98．3％、99．9％。内源性类ALV-J gp85序列与外源性ALV-J gp85基因具有相似或一致的ORF和Jameson-Worrlf抗原表位优势。     

Antifungal and Root Surface Colonization Properties of GFP-Tagged Paenibacillus brasilensis PB177

Summary This study evaluates the potential of Paenibacillus brasilensis strain PB177 to inhibit phytopathogenic fungi commonly causing maize diseases and to colonize maize plants. In vitro assays demonstrated antagonistic activity against the fungal pathogens, Fusarium moniliforme and Diplodia macrospora. The PB177 strain was tagged with the gfp gene, encoding the green fluorescent protein (GFP) and GFP-tagged bacteria were detected attached to maize roots by stereo- and confocal microscopy. The GFP-tagged bacteria were also used to treat maize seeds before challenging the seeds with two phytopathogenic fungi. The results demonstrated that the bacterial cells are mobilized to the maize roots in the presence of the fungal pathogens. The ability of P. brasilensis PB177 to inhibit fungal growth in vitro and its capability of colonization of maize roots in vivo suggest a potential application of this strain as a biological control agent. This is the first report on the successful introduction of the GFP marker gene into a P. brasilensis strain, enabling the direct observation of these promising plant growth promoting bacteria on maize roots in situ.     

非富营养化淡水系统中被忽略的生态系统驱动因素:可溶性腐殖质－简要的回顾与展望

HS are complex organic molecules comprising thehighest proportion(50%—80%)of dissolved organicmatter(DOM)in all freshwater ecosystems.In any non-eutrophicated freshwater ecosystems and with concentra-tions between1and100mg/L,[occasionally even more,for instance:Australian wetlands upto300mg/L DOC[1],Brazilian coastal lagoons160—200mg/L DOC[2],HSex-ceedthe organic carbon of all living organisms byroughlyone order of magnitude[3—6].Jones(1998)[7]emphasizesthat all freshwaters contain so…     

石刁柏胚性细胞诱导过程中的内源激素和多胺含量变化

用高效液相色谱法分析石刁柏愈伤组织胚性细胞诱导过程中不同时期内源激素和多胺含量的结果表明,在胚性细胞诱导过程中,Put和GA3一直呈上升趋势,胚性细胞出现时,IAA、Put和GA3含量都达到最高水平,显示高含量的IAA以及高比例的Pu“（Spd＋Spm）可能有利于胚性细胞的形成。