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排序方式: 共有375条查询结果,搜索用时 62 毫秒
111.
In this study, an automated surface plasmon resonance (SPR)-based biosensor was compared with a quartz crystal microbalance (QCM) biosensor. The two biosensor systems were used for characterizing a site-directed monoclonal antibody (mAb), raised against the C-terminal heptapeptide ET-115–21 of the human endothelin (ET-1). The mAb was characterized by its capacity for binding to ET-1, ET-3, Big.ET-122–38, the C-terminal (ET-115–21, ET-116–21, ET-117–21), and six derivates of ET-116–21, each containing a substitution with alanine (Ala) of a single aminoacid from position 16–21, respectively. The mAb reacted well with ET-1 and its fragments ET-115–21, ET-116–21, ET-117–21, but showed only a partial cross-reaction with ET-3, and did not bind human Big.ET-122–38. The Ala substitution on position 16,17, or 19 of ET-116–21 did not affect the antibody binding capacity of the hexapaptide ET-116–21. On the contrary, Ala substitution or Asp18, Ile20 and particularly Trp21, inhibited its immunoreactivity. Thus the C-terminal represents an immunodominant epitope in ET-1 and is important for antibody binding. The SPR and QCM response signals were similar in shape but differing in time scales, reflecting differences in detection mechanisms. With regard to the fundamental problem of comparing different measurement principles, we found a good correlation between results obtained using the BIA technology and the QCM. 相似文献
112.
The sarcoplasmic reticulum (SR) is composed of two fractions, the heavy fraction that contains proteins involved in Ca2+ release, and the light fraction enriched in Ca(2+)-ATPase (SERCA), an enzyme responsible for Ca2+ transport from the cytosol to the lumen of SR. It is known that in red muscle thyroid hormones regulate the expression of SERCA 1 and SERCA 2 isoforms. Here we show the effects of thyroid hormone on SERCA expression and distribution in light and heavy SR fractions from rabbit white and red muscles. In hyperthyroid red muscle there is an increase of SERCA 1 and a decrease of SERCA 2 expression. This is far more pronounced in the heavy than in the light SR fraction. As a result, the rates of Ca(2+)- ATPase activity and Ca(2+)-uptake by the heavy vesicles are increased. In hypothyroidism we observed a decrease in SERCA 1 and no changes in the amount of SERCA 2 expressed. This promoted a decrease of both Ca(2+)-uptake and Ca(2+)-ATPase activity. While the major differences in hyperthyroidism were found in the heavy SR fraction, the effects of hypothyroidism were restricted to light SR fraction. In white muscle we did not observe any significant changes in either hypo- or hyperthyroidism in both SR fractions. Thus, the regulation of SERCA isoforms by thyroid hormones is not only muscle specific but also varies depending on the subcellular compartment analyzed. These changes might correspond to the molecular basis of the altered contraction and relaxation rates detected in thyroid dysfunction. 相似文献
113.
Leopoldo Alfonso 《遗传、选种与进化》2005,37(5):417-435
This article investigates the application of meta-analysis on livestock candidate gene effects. The PvuII polymorphism of the ESR gene is used as an example. The association among ESR PvuII alleles with the number of piglets born alive and total born in the first (NBA1, TNB1) and later parities (NBA, TNB) is reviewed by conducting a meta-analysis of 15 published studies including 9329 sows. Under a fixed effects model, litter size values were significantly lower in the "AA" genotype groups when compared with "AB" and "BB" homozygotes. Under the random effects model, the results were similar although differences between "AA" and "AB" genotype groups were not clearly significant for NBA and TNB. Nevertheless, the most noticeable result was the high and significant heterogeneity estimated among studies. This heterogeneity could be assigned to error sampling, genotype by environment interaction, linkage or epistasis, as referred to in the literature, but also to the hypothesis of population admixture/stratification. It is concluded that meta-analysis can be considered as a helpful analytical tool to synthesise and discuss livestock candidate gene effects. The main difficulty found was the insufficient information on the standard errors of the estimated genotype effects in several publications. Consequently, the convenience of publishing the standard errors or the concrete P-values instead of the test significance level should be recommended to guarantee the quality of candidate gene effect meta-analyses. 相似文献
114.
Rappelli P Folgosa E Solinas ML Dacosta JL Pisanu C Sidat M Melo J Cappuccinelli P Colombo MM 《FEMS immunology and medical microbiology》2005,43(1):67-72
A study was conducted on the circulation of potentially diarrheagenic Escherichia coli in two groups of children, both under the age of seven. The first group (548 children) suffered from mild diarrhea and attended the Xipamanine Health Center of Maputo, in Mozambique. The second group (380 children) included randomly chosen, asymptomatic, children from the same population. A total of 503 E. coli strains were isolated from the two groups of children (n=375 and 128, respectively). All E. coli strains were genotypically and phenotypically screened. The presence of virulence-associated genes was assessed by a set of multiplex PCR specific for st and lt genes of enterotoxic Escherichia coli (ETEC), eae and bfpA genes of enteropathogenic E. coli (EPEC), stx(1) and stx(2) of enterohemorrhagic E. coli (EHEC), ial of enteroinvasive E. coli (EIEC) and the species-specific gene uidA. Adhesion and citotoxicity of isolated E. coli were evaluated in vitro on different cell cultures. A total of 37 isolates harbored virulence-associated genes: 18 were classified as ETEC, (15 from symptomatic, and three from asymptomatic children), 16 as EPEC (respectively, 13 and 3) and three EIEC in the symptomatic group. No stx(1) or stx(2) genes, associated with enterohemorrhagic E. coli were found. On the basis of the adhesion pattern on HeLa cells, 167 E. coli were classified as diffusely adhering, (125 in patients and 42 in controls) and 67 as enteroaggregative, (50 and 17, respectively). To the best of our knowledge, this is the first report in the literature on the circulation of potentially diarrheagenic E. coli in Mozambique. 相似文献
115.
Gutiérrez-Ortega A Sandoval-Montes C de Olivera-Flores TJ Santos-Argumedo L Gómez-Lim MA 《Transgenic research》2005,14(6):877-885
Transgenic plants have been employed successfully as a low-cost system for the production of therapeutically valuable proteins,
including antibodies, antigens and hormones. Here, we report the expression of a cytokine with immunomodulatory function,
mouse interleukin-12 (IL-12), in transgenic tomato plants. Single-chain mouse IL-12 driven by the CaMV 35S promoter, accumulates
to high levels in leaves and fruits (up to 7.3 and 3.4 μg per gram of fresh weight, respectively). Mouse IL-12 expressed in
tomato displays biological activity in vitro, as determined by interferon-γ (IFN-γ) secretion by T cells. Possible uses of this plant-based cytokine involving mucosal
delivery are discussed 相似文献
116.
In some zones of Antarctica's cold and dry desert, the extinction of cryptoendolithic microorganisms leaves behind inorganic traces of microbial life. In this paper, we examine the transition from live microorganisms, through their decay, to microbial fossils using in situ microscopy (transmission electron microscopy, scanning electron microscopy in back-scattered electron mode) and microanalytical (energy dispersive X-ray spectroscopy) techniques. Our results demonstrate that, after their death, endolithic microorganisms inhabiting Commonwealth Glacier sandstone from the Antarctica McMurdo Dry Valleys become mineralized. In some cases, epicellular deposition of minerals and/or simply filling up of empty moulds by minerals leads to the formation of cell-shaped structures that may be considered biomarkers. The continuous deposition of allochthonous clay minerals and sulfate-rich salts fills the sandstone pores. This process can give rise to microbial fossils with distinguishable cell wall structures. Often, fossilized cell interiors were of a different chemical composition to the mineralized cell walls. We propose that the microbial fossil formation observed was induced by mineral precipitation resulting from inorganic processes occurring after the death of cryptoendolithic microorganisms. Nevertheless, it must have been the organic template that provoked the diffusion of mineral elements and gave rise to their characteristic distribution pattern inside the fossilized cells. 相似文献
117.
Carlo Polidori Cayetano Gutiérrez-Cánovas Enrique Sánchez José Tormos Leopoldo Castro David Sánchez-Fernández 《Ecological Entomology》2020,45(1):130-141
1. Climate change is expected to produce shifts in species distributions as well as behavioural, life-history, and/or morphological adaptations to find suitable conditions or cope with the altered environment. Most of our knowledge on this issue comes from studies on vertebrates, mainly endotherm species. However, it remains uncertain how small ectotherms, such as insects, respond to increased temperature. 2. This study tested whether climate change over the last 100 years (1904–2013) has affected morphological and functional traits in workers of the social wasp Dolichovespula sylvestris in the Iberian Peninsula. 3. Head width and forewing length, as well as body mass and wing area (assuming no change in shape), decreased over time and with increased mean annual temperature, even when controlling for geographical location and altitude. Interestingly, wing size decreased with a steeper slope compared with body size. If there is no change in wing shape, this would lead to an invariable wing loading (body mass:wing area ratio) over time, with potential consequences on flying ability of more recent (and thus smaller) wasp individuals. 4. These results suggest that recent climate change is leaving morphological signatures in social wasps, increasing the evidence for this phenomenon in insects. The data furthermore suggest that the known efficient thermoregulatory ability of social insect colonies may not successfully buffer the effect of global warming. 相似文献
118.
Artur Junio Togneri Ferron Bruno Barcellos Jacobsen Paula Grippa Sant’Ana Dijon Henrique Salomé de Campos Loreta Casquel de Tomasi Renata de Azevedo Mello Luvizotto Antonio Carlos Cicogna André Soares Leopoldo Ana Paula Lima-Leopoldo 《PloS one》2015,10(9)
Obesity has been shown to impair myocardial performance. Some factors have been suggested as responsible for possible cardiac abnormalities in models of obesity, among them beta-adrenergic (βA) system, an important mechanism of regulation of myocardial contraction and relaxation. The objective of present study was to evaluate the involvement of βA system components in myocardial dysfunction induced by obesity. Thirty-day-old male Wistar rats were distributed in control (C, n = 25) and obese (Ob, n = 25) groups. The C group was fed a standard diet and Ob group was fed four unsaturated high-fat diets for 15 weeks. Cardiac function was evaluated by isolated papillary muscle preparation and βA system evaluated by using cumulative concentrations of isoproterenol and Western blot. After 15 weeks, the Ob rats developed higher adiposity index than C rats and several comorbidities; however, were not associated with changes in systolic blood pressure. Obesity caused structural changes and the myocardial responsiveness to post-rest contraction stimulus and increased extracellular calcium (Ca2+) was compromised. There were no changes in cardiac function between groups after βA stimulation. The obesity was not accompanied by changes in protein expression of G protein subunit alpha (Gsα) and βA receptors (β1AR and β2AR). In conclusion, the myocardial dysfunction caused by unsaturated high-fat diet-induced obesity, after 15 weeks, is not related to βAR system impairment at the receptor-signalling pathway. 相似文献
119.
120.
Ana Paula Sayuri Sato José Leopoldo Ferreira Antunes Roudom Ferreira Moura Fabíola Bof de Andrade Yeda Aparecida Oliveira Duarte Maria Lúcia Lebr?o 《PloS one》2015,10(4)