Protein synthesis is not required for the inhibitory effect of selenite on cell colony formation and RNA synthesis

Selenite has been shown to undergo intracellular metabolism that results in its conversion to other low molecular weight Secontaining species and also to its incorporation into a selenocysteine residue in selenoprotein. In order to investigate whether the incorporation into protein is required for the cytotoxic effects of selenite, we have examined whether inhibition of protein synthesis prevents the inhibitory effect of selenite on the ability of cells to form colonies or to synthesize RNA. We have found that treatment of HeLa cells with cycloheximide inhibited protein synthesis by >90% but had no effect on the inhibitory effect of selenite on cell colony formation or RNA synthesis. Since protein synthesis is not necessary for these cytotoxic effects of selenite they are unlikely to result from an increase in the synthesis of selenoproteins.     

春雷霉素高产菌株US95#的选育及大罐发酵工艺控制

紫外线与光修复交替处理春雷霉素产生菌得到了高产突变株,再结合自然分离选出了US95^#。该菌株不但产量高,还具有稳定的遗传性能,并在大罐良好发酵工艺控制和条件下,罐发酵水平在春雷霉素生产上有了重大突破,发酵水平比历史最高水平提高12．9％。     

黑米色素提取工艺的优化

黑米稻为中国著名的珍稀稻种。黑米不仅富含的蛋白质、氨基酸、维生素以及钙、铁、锌、硒等矿物营养元素,而且还含有具重要天然色素＂黑米色素＂。由于黑米营养价值高于普通稻米,且富含花色甘类抗氧化色素,是现代食品行业理想的天然抗氧化剂来源。以黑糙米作为研究材料,无水乙醇作为提取溶剂,采用萃取法对黑米色素的提取工艺做了较为全面的研究。试验结果表明：以无水乙醇作为黑米色素萃取剂时,按照料液比（w/v）1∶8,萃取时间60 min,萃取温度80℃,黑米色素提取效果最佳。     

Attitude to Animals and Empathy: Comparing Animal Protection and General Community Samples

ABSTRACT

Although a number of studies have examined a range of demographic and personality variables that may impact upon attitudes towards the treatment of non-human species, little consensus has been reached within the literature. The aim of the current study was to evaluate and assess levels of human-directed empathy and attitudes towards the treatment of animals in two diverse populations, namely the general community (n = 543) and those within the animal protection field (n = 389). Both groups of participants completed the Attitude Towards the Treatment of Animals Scale (AAS) and the Davis Interpersonal Reactivity Index (IRI), a measure of human-directed empathy. Comparisons between the two samples indicated that those within the animal protection community scored more highly on both the animal attitude and human-directed empathy measures. Correlational analyses revealed a positive relation between AAS and IRI scores for both samples, whilst the strength of the correlation was greater for those within the animal protection sample. These findings are discussed.     

Role of Liv-52 in protection against beryllium intoxication

An ayurvedic medicine, Liv-52, was studied as a prophylactic agent against beryllium-induced toxicity in rats. Administration of berylliumper se caused severe degenerative and necrotic changes in kidneys, liver, and uterus. Beryllium exposure also reduced glycogen content, activities of alkaline phosphatase, succinate-dehydrogenase, and adenosine-triphosphatase in these organs. On the contrary, activities of acid phosphatase and glucose-6-phosphatase showed marginal increase. Liv-52-primed rats exhibited comparatively less marked toxic effects.     

种子超干贮藏技术应用面临的问题和研究方向

种子超干贮藏技术对种质资源保存具有很大的应用前景,但鉴于目前的研究进展,其应用还存在诸多技术上的问题。本文对种子超干贮藏技术在种子库中应用所面临的挑战以及需要开展的研究内容进行了如下几个方面的讨论：种子贮藏安全含水量下限的多样性决定了超干技术应用的复杂性;超干贮藏含水量安全下限的确定尚未有可靠的方法;超干贮藏的种子吸胀前需要恰当的预处理以避免吸胀损伤;超干处理前外源抗氧剂预处理可能改善超干贮藏效果;无氧条件可能对超干贮藏具有增效作用;糖类物质以及两性物质对种子在超干处理及超干贮藏过程中的保护作用。     

Decreased thiamine and magnesium levels in the potentiation of the neurotoxicity of lead in occupational lead exposure

The relationship between blood lead (Pb) and serum levels of calcium and of neural nutrients such as thiamine and magnesium (Mg) has been determined in a Nigerian population that is occupationally exposed to Pb. Forty-seven male Pb workers were recruited as test subjects and 25 males unexposed to Pb served as controls. The test subjects were classified into three groups, based on severity of exposure to Pb. Blood lead (BPb) and the serum levels of Mg, thiamine, and calcium were determined in both test subjects and controls. The mean blood Pb level was not significantly higher in Pb workers. In contrast, Mg and thiamine levels were significantly decreased (p<0.05; p<0.01, respectively). However, the calcium level was not significantly lower in test subjects than in controls. Also, there was a significant negative correlation between serum thiamine and blood Pb levels (r=-0.50; p<0.01). Furthermore, there was a significant negative correlation between serum calcium and BPb levels (r=-0.41; p<0.01). This study has shown that relatively low BPb levels can enhance Pb absorption and also potentiate Pb neurotoxicity in the presence of decreased serum thiamine and Mg levels.     

Integrating frugivory and animal movement: a review of the evidence and implications for scaling seed dispersal

General principles about the consequences of seed dispersal by animals for the structure and dynamics of plant populations and communities remain elusive. This is in part because seed deposition patterns emerge from interactions between frugivore behaviour and the distribution of food resources, both of which can vary over space and time. Here we advocate a frugivore‐centred, process‐based, synthetic approach to seed dispersal research that integrates seed dispersal ecology and animal movement across multiple spatio‐temporal scales. To guide this synthesis, we survey existing literature using paradigms from seed dispersal and animal movement. Specifically, studies are discussed with respect to five criteria: selection of focal organisms (animal or plant); measurement of animal movement; characterization of seed shadow; animal, plant and environmental factors included in the study; and scales of the study. Most studies focused on either frugivores or plants and characterized seed shadows directly by combining gut retention time with animal movement data or indirectly by conducting maternity analysis of seeds. Although organismal traits and environmental factors were often measured, they were seldom used to characterize seed shadows. Multi‐scale analyses were rare, with seed shadows mostly characterized at fine spatial scales, over single fruiting seasons, and for individual dispersers. Novel animal‐ and seed‐tracking technologies, remote environmental monitoring tools, and advances in analytical methods can enable effective implementation of a hierarchical mechanistic approach to the study of seed dispersal. This kind of mechanistic approach will provide novel insights regarding the complex interplay between the factors that modulate animal behaviour and subsequently influence seed dispersal patterns across spatial and temporal scales.     

Climatic and technological ceilings for Chinese rice stagnation based on yield gaps and yield trend pattern analysis

Climatic or technological ceilings could cause yield stagnation. Thus, identifying the principal reasons for yield stagnation within the context of the local climate and socio‐economic conditions are essential for informing regional agricultural policies. In this study, we identified the climatic and technological ceilings for seven rice‐production regions in China based on yield gaps and on a yield trend pattern analysis for the period 1980–2010. The results indicate that 54.9% of the counties sampled experienced yield stagnation since the 1980. The potential yield ceilings in northern and eastern China decreased to a greater extent than in other regions due to the accompanying climate effects of increases in temperature and decreases in radiation. This may be associated with yield stagnation and halt occurring in approximately 49.8–57.0% of the sampled counties in these areas. South‐western China exhibited a promising scope for yield improvement, showing the greatest yield gap (30.6%), whereas the yields were stagnant in 58.4% of the sampled counties. This finding suggests that efforts to overcome the technological ceiling must be given priority so that the available exploitable yield gap can be achieved. North‐eastern China, however, represents a noteworthy exception. In the north‐central area of this region, climate change has increased the yield potential ceiling, and this increase has been accompanied by the most rapid increase in actual yield: 1.02 ton ha^?1 per decade. Therefore, north‐eastern China shows a great potential for rice production, which is favoured by the current climate conditions and available technology level. Additional environmentally friendly economic incentives might be considered in this region.