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The objective of this study was to investigate the difference in electrophoretic mobility between partially and fully poly(ethylene glycol)-conjugated poly(amidoamine) dendrimers (part-PEG-PAMAM and full-PEG-PAMAM, respectively) using a microchip capillary gel electrophoresis (MCGE). While MCGE allowed size-based separation of PEG-PAMAMs prepared with monomethoxy PEG-nitrophenyl carbonate, full-PEG-PAMAMs migrated slower than part-PEG-PAMAMs that were similar in size or larger. When the measured molecular weights obtained from MCGE analysis and the calculated molecular weights were plotted, each part-PEG-PAMAM and full-PEG-PAMAM showed correlation coefficients greater than 0.98. This study indicates that MCGE would be useful for characterizing PEG-PAMAMs with different PEGylation degrees. 相似文献
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Host genotype–endosymbiont associations and their relationship with aphid parasitism at the field level 下载免费PDF全文
1. The relationship between endosymbionts and insects represent complex eco‐evolutionary interactions. Vertically transmitted endosymbionts can be a source of evolutionary novelty by conferring ecologically important traits to their insect hosts, such as protection against natural enemies. Host–endosymbiont associations could constitute an adaptive complex (holobiont) on which selective pressures present in the environment can act, being transferred to the next generation. 2. Although several laboratory‐based studies have confirmed host genotype × symbiont interactions, few studies have been directed at those associations in the natural populations and their ability to protect themselves from parasitism pressure at the field level. 3. A field‐based approach to study the aphid genotype–endosymbiont associations and its relationship with the total parasitism in the grain aphid Sitobion avenae was conducted. From the field study, experiments were carried out to study the defensive effect of the two most common facultative endosymbionts (Regiella insecticola and Hamiltonella defensa) present in S. avenae against one of the most important parasitoid species, Aphidius ervi. 4. Evidence is presented here of a high specificity of the aphid clone–endosymbiont associations in the field; however, the field and experimental results here do not support a relationship between the aphid clone–endosymbiont associations and a proxy of total parasitism in S. avenae. These findings highlight the importance of particular host clone–endosymbiont couplings as a key factor in gaining an understanding of the coevolutionary dynamics of endosymbionts in nature and their effect on the invasive potential of pest insects. 相似文献
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J.-Y. Roh H.-W. Park Y.-H. Je D.-W. Lee B.-R. Jin H.-W. Oh S. S. Gill & S.-K. Kang 《Letters in applied microbiology》1997,24(6):451-454
Bacillus thuringiensis NTB-1 isolated from soil samples in Korea produces ovoidal parasporal inclusions with proteins of approximately 24–40 kDa in size. Although serological study indicated that the isolate has a flagella (H) antigen identical with subsp. israelensis , it seemed to be non-insecticidal against Lepidoptera and Coleoptera as well as Diptera. To investigate the activity of non-insecticidal B. thuringiensis transformed with insecticidal crystal protein genes, cryIVD and cytA genes of B. thuringiensis subsp. morrisoni PG-14, highly toxic to mosquito larvae, were introduced into the isolate NTB-1. The expression of mosquitocidal crystal protein genes in NTB-1 was characterized by SDS–PAGE analysis and electron microscopy. The results showed that crystalline inclusions of host, CryIVD and CytA were stably expressed in the transformant. However, the mosquitocidal activity of transformant was similar to that of B. thuringiensis subsp. kurstaki Cry− B harbouring cryIVD and cytA genes, demonstrating that a synergistic effect by an interaction of both introduced insecticidal and resident non-insecticidal crystal proteins was not observed. 相似文献
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Nicolas Tavaglione Angela K. Martin Nathalie Mezger Sophie Durieux‐Paillard Anne François Yves Jackson Samia A. Hurst 《Bioethics》2015,29(2):98-107
In the literature on medical ethics, it is generally admitted that vulnerable persons or groups deserve special attention, care or protection. One can define vulnerable persons as those having a greater likelihood of being wronged – that is, of being denied adequate satisfaction of certain legitimate claims. The conjunction of these two points entails what we call the Special Protection Thesis. It asserts that persons with a greater likelihood of being denied adequate satisfaction of their legitimate claims deserve special attention, care or protection. Such a thesis remains vague, however, as long as we do not know what legitimate claims are. This article aims at dispelling this vagueness by exploring what claims we have in relation to health care – thus fleshing out a claim‐based conception of vulnerability. We argue that the Special Protection Thesis must be enriched as follows: If individual or group X has a greater likelihood of being denied adequate satisfaction of some of their legitimate claims to (i) physical integrity, (ii) autonomy, (iii) freedom, (iv) social provision, (v) impartial quality of government, (vi) social bases of self‐respect or (vii) communal belonging, then X deserves special attention, care or protection. With this improved understanding of vulnerability, vulnerability talk in healthcare ethics can escape vagueness and serve as an adequate basis for practice. 相似文献
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Large‐scale biodiversity maps are essential to macroecology. However, between‐region comparisons can be more useful if patterns of observed species richness are supplemented by variations in dark diversity – the absent portion of the species pool. We aim to quantify and map plant diversity across Europe by using a measure that accounts for both observed and dark diversity. To do this we need to delimit suitable species pools, and evaluate the potential and limitation of a large‐scale dataset. We used Atlas Florae Europaeae (ca 20% of European plant species mapped within 50 × 50 km grid cells) and defined for each grid cell several species pools by applying various geographical and environmental filters: geographic species pool (number of species within 500 km radius), biogeographic species pool (additionally incorporating species distribution patterns, i.e. dispersion fields), site‐specific species pool (additionally integrating environmental preferences of species based on species co‐occurrence). We integrated dark diversity and observed diversity at a relative scale to calculate the completeness of site diversity: logistic expression of observed and dark diversity. We tested whether our results are robust against regional variation in data availability. We used independent regional databases to test if Atlas Florae Europaeae is a representative subset of total species richness. Environmental filtering was the most influential determinant of species pool size with more species filtered out in southern Europe. Both observed and dark diversity adhered to the well‐known latitudinal gradient, but completeness of site diversity varied throughout Europe with no latitudinal trend. Dark diversity patterns were fairly insensitive to variations in regional sampling intensity. Atlas Florae Europaeae represented well the total variation in plant diversity. In summary, dark diversity and completeness of site diversity add valuable information to broad‐scale diversity patterns since observed diversity is expressed at a relative scale. 相似文献
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