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逻辑斯缔议程在研究原始生物大分子动态及生命起原问题中的应用 总被引:2,自引:0,他引:2
通过论证及重新定义逻辑斯缔方程,本文提出和进一步发展了原始生物大分子动态的数学模型,对该模型的4种竞争增长结果进行分析,得出最有可能的原始生物大分子的发展动态,并由此推导出原始生物圈中较大量存在的只是种类单一的原始生物大分的结论,对这一结论在生命起源和牲进化中的意义进行了探讨。指出生命起源初期的生物多样性是很低的,原始生物世界是一重复序列或重复结构的世界,生物进行是通过不断增加扩展生态位,使生物多 相似文献
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通过论证及重新定义逻辑斯缔方程,本文提出和进一步发展了原始生物大分子动态的数学模型.对该模型的4种竞争增长结果进行分析,得出最有可能的原始生物大分子的发展动态,并由此推导出原始生物圈中较大量存在的只是种类单一的原始生物大分子的结论。对这一结论在生命起源和生物进化中的意义进行了探讨,指出生命起源初期的生物多样性是很低的,原始生物世界是一个重复序列或重复结构的世界,生物进化是通过不断增加和扩展生态位,使生物多样性不断提高。最后,讨论了生态学的概念和方法在微观水平上应用的理论基础,指出从生态学的角度去进行分子生物学的研究是一种发展趋势。 相似文献
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生命是物质的。生命的本质在于生命大分子间的相互作用。阐明生命现象的规律,必须建立在阐明生物大分子结构与功能的基础上。蛋白质和核酸是2种重要的生物大分子,蛋白质是生命活动的主要承担者,核酸是遗传信息的携带者和传递执行者。遗传信息的多样性决定蛋白质分子的多样性,进而体现生命系统的复杂性和多样性。生物学新课程标准对该部分的要求是: 相似文献
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引言自然保护区是对生物多样性加以保护、研究和持续利用的关键区域。中国生物物种资源丰富,已建立自然保护区700多处,在实施“联合国保护生物多样性公约”方面有着巨大的潜力。为实现这一目标,需要国内和国际的联合行动。为积极参与保护生物多样性的联合行动,1993年4月中国人与生物圈国家委员会第八次会议决定在中国建立生物圈保护区网络。做出这一决定的考虑是: ——人与生物圈计划在中国是十分有影响的国际渠道,这一计划所提出的生物圈保护区的 相似文献
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生物多样性的起源与进化是生命科学领域最重要的科学问题之一。多组学数据的积累和相关分析技术的发展, 极大地推动了人们对生物多样性起源与进化的理解和研究, 使得阐明生物进化事件发生的过程与机制成为可能。值此《生物多样性》创刊30周年之际, 本文简要回顾生物多样性起源与进化相关研究在近年来取得的重要研究进展, 以期帮助读者了解该研究方向的发展现状。过去10年中, 生物多样性起源与进化相关研究在生命之树重建、生物多样性时空分布格局、物种概念、物种形成与适应性进化以及新性状起源与多样化等方面取得了许多重要进展, 并在此基础上厘清了许多分类单元间的系统发育关系、揭示了生物多样性分布格局的部分历史成因、提出了新的物种概念和物种形成模型、阐明了新性状和新功能发生的部分分子机制。我们认为, 更精准地重建生命之树、深入挖掘基因组数据以及多学科交叉融合将是今后生物多样性研究的主要趋势。 相似文献
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鉴于全球植被/生物群区在现状气候条件下已经被很好地模拟并在未来气候变化情景下得到很好的预测,人们有必要和急需模拟大尺度(区域、洲际至全球)植物多样性的分布格局。陆地生物圈模型的发展(从生物地理模型和生物地球化学模型到动态和耦合的植被模型),气候-生物多样性相互关系和生产力-生物多样性相互关系研究成果的增多,以及基于现有生物多样性调查的全球生物多样性理论和经验制图的进步,加大了模拟大尺度植物多样性格局的可能性。本文的目的是:综述当前气候-生物多样性相互关系和生产力-生物多样性相互关系的主要研究成果以及大尺度 相似文献
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生物质谱分析的研究进展及临床应用 总被引:1,自引:0,他引:1
质谱分析技术已应用于化学、化工、环境、能源、医药、运动医学、刑侦科学、生命科学、材料科学等各个领域。阐述目前生物质谱技术的类型、原理以及在医学领域中的应用,进而分析质谱技术在未来发展的前景。 相似文献
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The potential consequences of deploying weed and non-weed floral resources in a three trophic-level system were evaluated in the laboratory. Four flowering plants were used: the two common weeds shepherd’s purse Capsella bursa-pastoris (globally widespread) and white rocket Diplotaxis erucoides (a common weed in Europe) and two common flowering plants: buckwheat Fagopyrum esculentum and alyssum Lobularia maritima. Adults of the aphid parasitoid Diaeretiella rapae were exposed to flowering buckwheat and survived 4–5 times longer than those in the control (water only) and 2–3 times longer than when provided with flowering alyssum, or the other two species. All plant species significantly increased parasitoid longevity, egg load and achieved fecundity compared with the control, with buckwheat having the greatest effect. This work illustrates that the functional diversity of ‘weeds’, if appropriately managed, has potential to enhance biological control efficacy without the need for agronomic and other challenges which are involved in adding specific non-crop flowering plants such as buckwheat to agroecosystems. In the field, factors such as the plants’ phenology, agronomy and competitiveness with the crop will need to be evaluated before they can be truly ranked. 相似文献
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The insecticidal activities of the exotoxin produced by three varieties of Bacillus thuringiensis grown in six fermentation media were determined by testing the supernatants against larvae of the house fly, Musca domestica, and the black cutworm, Agrotis ipsilon. The activities of the exotoxins from the isolates varied when they were grown in the same medium and also when they were grown in different media. When an isolate of B. thuringiensis var. thuringiensis, and of var. tolworthi were grown in proflo broth, the supernatants produced were more toxic to house fly than to black cutworm larvae, indicating the presence of more than one exotoxin. Autoclaving the supernatants for 15 and 30 min further demonstrated the presence of several exotoxins. 相似文献
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酶法制备海洋活性肽及其功能活性研究进展 总被引:1,自引:0,他引:1
海洋生物活性肽(Marine biological active peptide)是从海洋生物中提取的具有优化机体代谢环境、有益于机体健康的一类多肽。酶法制备海洋生物活性肽是目前最常用的制备方法,是通过适当的蛋白酶水解海洋生物蛋白来制备生物活性肽的一种方法。海洋生物活性肽在降血压、抗氧化、抗凝血及抗菌等方面效果显著,对治疗和预防疾病具有巨大潜力。介绍海洋生物活性肽在酶解制备及其生物学功能方面国内外研究进展,为进一步开展海洋活性多肽研究提供参考。 相似文献
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Biological networks in metabolic P systems 总被引:4,自引:0,他引:4
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Gremmeniella abietina (Lagerberg) Morelet is a pathogenic fungus that causes severe damage in coniferous forests, causing the death of the trees, in Central and Northern Europe, North America and Japan. Biological control (i.e. the use of biologically antagonistic organisms) is being considered as an alternative and an eco-friendly method to deal with plant diseases. Among such organisms several fungal endophytes have been successfully used to reduce or inhibit the growth of pathogens. Thus, the aim of this study was to evaluate the ability of several fungal endophytes to reduce the G. abietina spreading on pine seedlings, with the goal of exploring the mechanisms involved in that reduction. The experiment was carried out on two-year old Pinus halepensis seedlings under greenhouse conditions. Five fungal endophytes (Trichoderma spp., Aureobasidium pullulans, Aureobasidium spp., endophyte 20.1 and Leotiomycete spp.) obtained from healthy P. halepensis trees were used to evaluate their effect on six G. abietina isolates. The pathogen and the endophyte were both inoculated in every seedling. At the end of the experiment seedlings were cut and brought to the laboratory where the necrosis length and total phenol content of the plant were measured. The pathogen presence was determined by a nested PCR with specific primers of G. abietina. The presence of all endophytes significantly reduced the necrosis length caused by G. abietina in most of the cases. However, the phenolic content of the plant, which is an indicator of the activation of the plant’s defence mechanisms, had not increased with the endophyte inoculation. Therefore, the reduction in the necrosis observed could be attributed to a direct effect of the endophyte on the Gremmeniella spreading. These results suggest that the use of fungal endophytes could be an effective way to protect against G. abietina infections. 相似文献
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Cristine R. Zimmer Luciana L. Dias de Castro Sabrina M. Pires Adriane M. Delgado Menezes Paulo B. Ribeiro Fábio P. Leivas Leite 《Journal of invertebrate pathology》2013
The aim of this study was to evaluate the larvicidal activity, and sub lethal effects of entomopathogenic bacteria Brevibacillus laterosporus, Bacillus thuringiensis var. israelensis, B. thuringiensis var. kurstaki, and a commercial formulation of Bacillus sphaericus on Musca domestica. Bacterial suspensions were prepared in different concentrations and added to the diet of newly-hatched larvae which were monitored until the adult stage. The larvae were susceptible to the B. laterosporus, B. thuringiensis var. israelensis, and B. thuringiensis var. kurstaki bacteria in varied concentration levels. These bacteria have larvicidal and sub lethal effects on the development of flies, reducing both adult size, and impairing the reproductive performance of the species. 相似文献
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世界范围内“四大家鱼”入侵现状及其适应特性 总被引:1,自引:0,他引:1
原产中国的鲢(Hypophthalmichthys molitrix)、鳙(Aristichthys nobilis)、草鱼(Ctenopharyngodon idella)和青鱼(Mylopharyngodon piceus),即"四大家鱼",已分别被引入到世界上很多个国家和地区,在其中将近一半的地区成功入侵,远高于一般入侵生物的建群概率。这与其自身的高繁殖力、宽广的生理耐受性和食性,以及遗传结构多样性等特征有关,还与新栖息地环境因素密切相关。四大家鱼野外繁殖所需的具有一定流量、流速、足够长且通畅的河道,是其成功入侵的必备环境因素;气候因素也影响四大家鱼成功入侵的概率。此外,入侵地的饵料丰度以及与其他入侵生物的协同作用,也能促进四大家鱼在引入地建群之后的入侵速度和程度。 相似文献