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591.
黑曲霉吸附弱酸性艳蓝RAWL的机理 总被引:2,自引:0,他引:2
为了研究黑曲霉吸附弱酸性艳蓝RAWL(简称染料)的机理,通过红外光谱和化学修饰的方法,考察了黑曲霉对染料吸附性能的pn响应模式,表征了黑曲霉干粉菌体表面的主要官能团组成及不同官能团对吸附染料的贡献。实验结果表明:在强酸性(pH不大于2)条件下黑曲霉对染料的吸附效果最好;黑曲霉干粉菌体表面含有氨基、羧基和磷酸根;经脂质脱除、磷酸根酯化修饰、羧基酯化修饰、氨基甲基化修饰后对染料的吸附性能不变,而乙酰化氨基在酸性体系中失去质子化能力,对染料的吸附性能下降51.6%,说明低pH条件下氨基质子化导致带正电的黑曲霉干粉菌体与带负电的染料之间的静电引力是吸附染料的重要原因。 相似文献
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浅谈北京市城镇燃气改造工程的防雷安全 总被引:1,自引:0,他引:1
文章通过在防雷检测中发现的城镇居民生活用气改造工程中的防雷安全隐患进行了分析探讨,介绍了雷电对燃气供气管道的危害,给出了相应的解决措施。可供防雷安全检测和燃气管道防雷工程设计施工部门参考。 相似文献
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改性累托石吸附处理含镉废水 总被引:1,自引:1,他引:0
采用硫酸和高分子絮凝剂聚二甲基二烯丙基氯化铵对累托石进行改性,考察了改性累托石吸附处理模拟含镉废水的影响因素.实验结果表明,在废水质量浓度为50 mg/L、废水pH为6.0、改性累托石加入量为1.2g/L、吸附时间为90 min、废水温度为25℃的条件下,改性累托石对镉的去除率可达98.00%以上,改性累托石对镉的吸附符合Langmuir模型. 相似文献
596.
核基因组在细胞质雄性不育中的作用研究:背景与现状 总被引:6,自引:0,他引:6
郭骁才 《应用与环境生物学报》2001,7(3):297-301
细胞质雄性不育 (cytoplasmicmalesterility ,CMS) ,表现为小孢子发育异常、不能产生花粉或花粉败育 ,但卵细胞发育正常、可接受外来花粉而正常结实 ,系母性遗传 ,即细胞质遗传[1~ 4 ] .CMS的重要性 ,首先表现为在农业生产上的巨大经济应用价值[2~ 4 ] .杂种优势的发现和利用为粮食生产带来了革命 ,但杂种种子的生产过程却是很繁杂的 ,核心是要阻止母本的自花授粉结实、保证母本植株上所结的种子全部是杂种 ,即种子的纯度很高才能保证农业生产上的应用 .CMS ,由于其不能产生可育的花粉 ,即无自花授粉结… 相似文献
597.
Brood sex ratio is dependent on female mating status in polygynous great reed warblers 总被引:2,自引:0,他引:2
Isao Nishiumi 《Behavioral ecology and sociobiology》1998,44(1):9-14
Females capable of adjusting the sex ratio of their offspring should be more fit than females lacking such an ability. In
polygynous birds where breeding success in males is more strongly influenced by body size and/or attractiveness than in females,
females might produce more sons when predicting good conditions or when mating with attractive males. Polygynous great reed
warbler, Acrocephalusarundinaceus, males direct most of their feeding effort to the primary (first-hatching) nest and in these nests increase their feeding
effort in relation to the brood sex ratio (proportion of sons). Therefore, with the expectation of well-nourished sons, we
would predict that females which start breeding first within harems might produce more sons than those which start breeding
later, and in anticipation of sons with good genes, that females mated to polygynous males might produce more sons than females
mated to monogamous males. I took blood samples from hatchlings and determined the sex using DNA markers. The sex ratio of
primary (monogamous and polygynous primary) broods is more male-biased (mean 0.58 males, n = 50) than that of secondary (polygynous secondary and tertiary) broods (mean 0.46, n = 25). Moreover, in the secondary broods with the largest clutch (five eggs), in which offspring are most likely to suffer
food shortage, the sex ratio was distinctively female biased (mean 0.33, n = 10). In the primary broods, sex ratio was correlated to harem size. The results suggest that great reed warbler females
modify the brood sex ratio to produce both well-nourished sons and sons with good genes, but the former effect is probably
stronger than the latter factor.
Received: 11 March 1998 / Accepted after revision: 23 May 1998 相似文献
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The effects of fisheries on marine ecosystems, and their capacity to drive shifts in ecosystem states, have been widely documented. Less well appreciated is that some commercially valuable species respond positively to fishing‐induced ecosystem change and can become important fisheries resources in modified ecosystems. Thus, the ecological effects of one fishery can unintentionally increase the abundance and productivity of other fished species (i.e., cultivate). We reviewed examples of this effect in the peer‐reviewed literature. We found 2 underlying ecosystem drivers of the effect: trophic release of prey species when predators are overfished and habitat change. Key ecological, social, and economic conditions required for one fishery to unintentionally cultivate another include strong top–down control of prey by predators, the value of the new fishery, and the capacity of fishers to adapt to a new fishery. These unintended cultivation effects imply strong trade‐offs between short‐term fishery success and conservation efforts to restore ecosystems toward baseline conditions because goals for fisheries and conservation may be incompatible. Conflicts are likely to be exacerbated if fisheries baselines shift relative to conservation baselines and there is investment in the new fishery. However, in the long‐term, restoration toward ecosystem baselines may often benefit both fishery and conservation goals. Unintended cultivation can be identified and predicted using a combination of time‐series data, dietary studies, models of food webs, and socioeconomic data. Identifying unintended cultivation is necessary for management to set compatible goals for fisheries and conservation. Cultivo Accidental, Líneas de Base Cambiantes y el Conflicto entre los Objetivos para las Pesquerías y la Conservación 相似文献
600.