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21.
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The serum amyloid A (SAA) superfamily comprises a number of differentially expressed genes with a high degree of homology in mammalian species. SAA4, an apolipoprotein constitutively expressed only in humans and mice, is associated almost entirely with lipoproteins of the high-density range. The presence of SAA4 mRNA and protein in macrophage-derived foam cells of coronary and carotid arteries suggested a specific role of human SAA4 during inflammation including atherosclerosis. Here we underline the importance of ribosome binding site (rbs)-like sequences (also known as Shine-Dalgarno sequences) in the SAA4 cDNA for expression of recombinant SAA4 protein in Escherichia coli. In contrast to rbs sequences coded by the expression vectors, rbs-like sequences in the cDNA of target protein(s) are known to interfere with protein translation via binding to the small 16S ribosome subunit, yielding low or even no expression. Here we show that PCR mutations of two rbs-like sequences in the human SAA4 cDNA promote expression of considerable amounts of recombinant SAA4 in E.coli. 相似文献
23.
Abstract. Contrary to current assumptions, the reflex blood of two-spot ladybirds, Adalia bipunctata , and seven-spot ladybirds, Coccinella septempunctata , contains haemocyte-like cells. Furthermore, DNA can be extracted and amplified from coccinellid reflex blood, confirming the presence of haemocyte-like cells and demonstrating a nondestructive method of DNA extraction. 相似文献
24.
The members of the family Syngnathidae stand out among the bony fish for their specific parental care: the male bear embryos in a particular brood chamber or pouch. The physiological role of the latter is discussed in the literature in detail. The pouch is rather multifunctional; its osmoregulatory function is the most well studied. The unusual parental care supposes that some specific features should exist in the reproduction biology and development in these fish. This idea is supported by detailed studies of the ovaries and oogenesis in pipefish. On the other hand, the structure of the testes and specific features of spermatogenesis in the representatives of the family Syngnathidae remain poorly studied. The interest in the reproduction and development of pipefish is also determined, to a certain degree, by the fact that in the countries of Southeast Asia seahorses are objects of fishing and are used as a source of pharmacological materials comprising active compounds. Attempts to cultivate these fish have also been undertaken in these countries [13]. 相似文献
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Abstract. 1. Clip cages have been used widely by experimental ecologists to contain insects on plants.
2. Under controlled conditions, the effect of applying clip cages alone and clip cages and the chrysomelid beetle Gastrophysa viridula on systemic leaf expansion of Rumex obtusifolius was investigated. Treatments were applied to the fully expanded fourth leaf and expansion of leaf 8 was measured over a period of 22 days.
3. The application of clip cages reduced the rate at which leaf area increased and led to reductions in final leaf areas.
4. Clip cages have systemic effects on plant development and these effects are sustained even after the clip cage is removed. Investigators should take this into account in designing experiments. 相似文献
2. Under controlled conditions, the effect of applying clip cages alone and clip cages and the chrysomelid beetle Gastrophysa viridula on systemic leaf expansion of Rumex obtusifolius was investigated. Treatments were applied to the fully expanded fourth leaf and expansion of leaf 8 was measured over a period of 22 days.
3. The application of clip cages reduced the rate at which leaf area increased and led to reductions in final leaf areas.
4. Clip cages have systemic effects on plant development and these effects are sustained even after the clip cage is removed. Investigators should take this into account in designing experiments. 相似文献
27.
IgE antibodies in the sera of subjects allergic to beta-lactam antibiotics detect a spectrum of specificities ranging from side-chain groups to an entire penicillin or cephalosporin molecule. In addition to such structural heterogeneity of allergenic determinants, IgE antibodies in the sera of different allergic subjects show heterogeneous recognition responses. Detailed immunochemical studies were carried out on the sera of penicillin-allergic subjects that showed selective and unexpected reactions with the frequently prescribed penicillin, amoxicillin. Antibodies from one subject reacted only with the amoxicilloyl determinant while IgE from another subject showed multiple reactivity with penicilloyl and penicillanyl determinants of different penicillins but not with the amoxicilloyl determinant. Quantitative hapten inhibition studies revealed that the combining sites of the former antibodies were complementary to amoxicillin in a form that permits binding to the hydroxyaminobenzyl side-chain and the thiazolidine ring carboxyl. These conditions are satisfied with the drug in the '-oyl' but not in the '-anyl' form which involves linkage through the 2-carboxyl of the thiazolidine ring. With the second serum, adsorption studies showed that the wide-ranging reactivity of IgE was due to a single population of antibodies that detected a common specificity on the different penicillins. Combining site studies revealed clear recognition of the benzyl portion of the side-chain of benzylpenicilloyl, benzylpenicillanyl, ampicilloyl, ampicillanyl and amoxicillanyl determinants when free antibody access to the side-chain was possible but little or no recognition of the ring hydroxyl of amoxicillin. Such uninhibited access may not occur, however, when amoxicillin is conjugated in the '-oyl' form since opening the beta-lactam ring allows increased flexibility and rotation of the molecule and the possibility of close association of the hydroxyaminobenzyl side-chain of amoxicillin with the linked peptide carrier. In such close steric association, H-bonding involving the ring hydroxyl and amino acids of the carrier may prevent antibody access to the side-chain region of the amoxicilloyl determinant. 相似文献
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29.
Julio M. Singer Frederico Z. Poleto Patrícia Rosa 《Biometrical journal. Biometrische Zeitschrift》2004,46(4):460-473
We compare two models for the analysis of repeated ordinal categorical data: the classical parametric model for means of scores assigned to the categories of the response variable and a nonparametric model based on relative effects derived from the marginal distribution functions of the response. An example in the field of Dentistry is used to illustrate and to compare the models. We also consider a simulation study to evaluate the type‐I error rates and the power of tests under both models in a balanced design setup. The simulation results suggest that both approaches behave similarly for equally spaced scores but may perform differently otherwise. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
30.
Book reviewed in this article:
Applied Anthropology: The Aboriginal Arts and Crafts Industry . Jon Altman
Marketing Aboriginal Art in the 1990s . Jon Altman and Luke Taylor 相似文献
Applied Anthropology: The Aboriginal Arts and Crafts Industry . Jon Altman
Marketing Aboriginal Art in the 1990s . Jon Altman and Luke Taylor 相似文献