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101.
Anders Hedenström Timmy Fagerlund Mikael Rosén Ronnie Wirestam 《Journal of avian biology》2009,40(4):457-460
The amount of fat of a bird is a fundamental metric commonly used by avian biologists in studies of migration, winter energy management and condition. The methods used for estimating fat content range from simply measuring body mass and subtracting the estimated lean mass, visual scoring of subcutaneous fat deposits, to destructive extraction using a Soxhlet apparatus. We used magnetic resonance imaging (MRI) for non-invasive estimation of fat content in willow warblers Phylloscopus trochilus . According to an indirect comparison, made using a standardized fat scoring system as a common measure, the MRI method gave very similar fat amount as Soxhlet extraction and we discuss advantages of using MRI over alternative methods. It was also shown that the commonly used fat scoring system yielded a nonlinear relationship between fat mass and fat score. 相似文献
102.
Arranz R Mercado G Martín-Benito J Giraldo R Monasterio O Lagos R Valpuesta JM 《Journal of structural biology》2012,178(1):54-60
Microcin E492 is a low-molecular weight, channel-forming bacteriotoxin that generates amyloid structures. Using electron microscopy and image processing techniques several structural conformations can be observed. Prior to the conditions that induce amyloid formation and at its initial stage, microcin E492 molecules can be found in two main types of oligomers: a pentameric, pore-like structure consisting of globular monomers of ~25? diameter, and long filaments made up of stacked pentamers. The equilibrium between these structures depends on the properties of the solvent, because samples kept in methanol mainly show the pentameric structure. Amyloid induction in aqueous solvent reveals the presence, together with the above mentioned structures, of several amyloid structures such as flat and helical filaments. In addition, X-ray diffraction analysis demonstrated that the fibrils formed by microcin E492 presented cross-β structure, a distinctive property of amyloid fibrils. Based on the study of the observed structures we propose that microcin E492 has two conformations: a native one that assembles mainly into a pentameric structure, which functions as a pore, and an amyloid conformation which results in the formation of different types of amyloid filaments. 相似文献
103.
Willig Julia Biz Vianna Débora Renz Barreto Beckenkamp Aline Beckenkamp Liziane Raquel Sévigny Jean Wink Márcia Rosângela Buffon Andréia Pilger Diogo André 《Purinergic signalling》2020,16(1):29-40
Purinergic Signalling - Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm, characterized by the occurrence of the t(9;22)(q34;q11) translocation. First-line therapy for CML consists... 相似文献
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105.
Borja Cascales-Mi?ana Jesús Mu?oz-Bertomeu María Flores-Tornero Armand Djoro Anoman José Pertusa Manuel Alaiz Sonia Osorio Alisdair R. Fernie Juan Segura Roc Ros 《The Plant cell》2013,25(6):2084-2101
This study characterizes the phosphorylated pathway of Ser biosynthesis (PPSB) in Arabidopsis thaliana by targeting phosphoserine phosphatase (PSP1), the last enzyme of the pathway. Lack of PSP1 activity delayed embryo development, leading to aborted embryos that could be classified as early curled cotyledons. The embryo-lethal phenotype of psp1 mutants could be complemented with PSP1 cDNA under the control of Pro35S (Pro35S:PSP1). However, this construct, which was poorly expressed in the anther tapetum, did not complement mutant fertility. Microspore development in psp1.1/psp1.1 Pro35S:PSP1 arrested at the polarized stage. The tapetum from these lines displayed delayed and irregular development. The expression of PSP1 in the tapetum at critical stages of microspore development suggests that PSP1 activity in this cell layer is essential in pollen development. In addition to embryo death and male sterility, conditional psp1 mutants displayed a short-root phenotype, which was reverted in the presence of Ser. A metabolomic study demonstrated that the PPSB plays a crucial role in plant metabolism by affecting glycolysis, the tricarboxylic acid cycle, and the biosynthesis of amino acids. We provide evidence of the crucial role of the PPSB in embryo, pollen, and root development and suggest that this pathway is an important link connecting primary metabolism with development. 相似文献
106.
Ros Williams 《New genetics and society》2013,32(3):319-337
The UK's publically available blood stem cell infrastructure has undergone significant transformation in recent years as umbilical cord blood has joined adult donors as a viable clinical stem cell source. This paper describes the development of a collaborative governance arrangement between the UK's two domestic providers of blood stem cells: a public body and a charity. The paper argues that the collaborators, who stand to benefit from the alignment, legitimize their work through appeals to public good. It suggests that appeals to buy British obscure an inevitable requirement to cultivate international, networked stem cell exchange; the paper also explores collaborators' reinforcement of a supposed connection between human leukocyte antigen tissue type and ethnicity through claiming that the UK's ethnic minorities face an “unmet need.” By way of this, the paper demonstrates the interconnection of collaborators' institutional interests with concerns for national health equity. 相似文献
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108.
Malaria infection in the mosquito vector can be modulated by the vertebrate host, mosquito factors, and interactions between different parasite populations. Modulation of parasite development can be assessed through the study of gene expression. The present report describes a specific, sensitive, and nonradioactive method that permits assessment of parasite load and quantification of circumsporozoite protein gene expression during the sporogonic stages of Plasmodium yoelii yoelii and P. y. nigeriensis. A decrease in parasite load was observed when comparing DNA of oocysts on day 7 postinfection with that of oocysts and sporozoites on day 19. On day 7, parasites (oocysts) showed a marked increase of circumsporozoite protein expression when compared with that (sporozoites and oocysts) on day 19. The method developed in this work can be a valuable tool to understand parasite interaction mechanisms that are involved in mosquito malaria infections. 相似文献
109.
One approach to understanding processes that underlie skilled performing has been to study electrical brain activity using electroencephalography (EEG). A notorious problem with EEG is that genuine cerebral data is often contaminated by artifacts of non-cerebral origin. Unfortunately, such artifacts tend to be exacerbated when the subject is in motion, meaning that obtaining reliable data during exercise is inherently problematic. These problems may explain the limited number of studies using EEG as a methodological tool in the sports sciences. This paper discusses how empirical studies have generally tackled the problem of movement artifact by adopting alternative paradigms which avoid recording during actual physical exertion. Moreover, the specific challenges that motion presents to obtaining reliable EEG data are discussed along with practical and computational techniques to confront these challenges. Finally, as EEG recording in sports is often underpinned by a desire to optimise performance, a brief review of EEG-biofeedback and peak performance studies is also presented. A knowledge of practical aspects of EEG recording along with the advent of new technology and increasingly sophisticated processing models offer a promising approach to minimising, if perhaps not entirely circumventing, the problem of obtaining reliable EEG data during motion. 相似文献
110.
Julio Plaza-Diaz Carolina Gomez-Llorente Laura Campa?a-Martin Esther Matencio Inmaculada Ortu?o Rosario Martínez-Silla Carlos Gomez-Gallego Maria Jesús Periago Gaspar Ros Empar Chenoll Salvador Genovés Beatriz Casinos ángela Silva Dolores Corella Olga Portolés Fernando Romero Daniel Ramón Antonio Perez de la Cruz Angel Gil Luis Fontana 《PloS one》2013,8(10)
We previously described the isolation and characterization of three probiotic strains from the feces of exclusively breast-fed newborn infants: Lactobacillus paracasei CNCM I-4034, Bifidobacterium breve CNCM I-4035 and Lactobacillus rhamnosus CNCM I-4036. These strains were shown to adhere to intestinal mucus in vitro, to be sensitive to antibiotics and to resist biliary salts and low pH. In the present study, a multicenter, randomized, double-blind, placebo-controlled trial with 100 healthy volunteers in three Spanish cities was carried out to evaluate the tolerance, safety, gut colonization and immunomodulatory effects of these three probiotics. Volunteers underwent a 15-day washout period, after which they were randomly divided into 5 groups that received daily a placebo, a capsule containing one of the 3 strains or a capsule containing a mixture of two strains for 30 days. The intervention was followed by another 15-day washout period. Patients did not consume fermented milk for the entire duration of the study. Gastrointestinal symptoms, defecation frequency and stool consistency were not altered by probiotic intake. No relevant changes in blood and serum, as well as no adverse events occurred during or after treatment. Probiotic administration slightly modified bacterial populations in the volunteers’ feces. Intestinal persistence occurred in volunteers who received L. rhamnosus CNCM I-4036. Administration of B. breve CNCM I-4035 resulted in a significant increase in fecal secretory IgA content. IL-4 and IL-10 increased, whereas IL-12 decreased in the serum of volunteers treated with any of the three strains. These results demonstrate that the consumption of these three bacterial strains was safe and exerted varying degrees of immunomodulatory effects.