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961.
F. Xavier Gomis-Rüth 《Structure (London, England : 1993)》2013,21(11):1909-1910
962.
Two populations of Phyllariopsis purpurascens from the Straits of Gibraltar area were investigated during 1990 and 1991. This area has very strong currents (~2·5 m s-1 at spring tide). The first sporophytes (less than 0·5 cm in length) were observed in April; they disappeared after the first storm period in October. The estimated number of spores produced in an unilocular sporangium was 64. The fertility period started in May and continued until October, but the maximum sorus surface area (27%) was reached in September. The maximum sporangial density was 1476±236 mm-2. The slow development of fertility and its correlation with the seasonal increase in temperature suggest that sporangial development is controlled by temperature and not by photoperiod. The drag effect produced by the strong currents (at spring tides and storm periods) is sufficient to break adult plants (with 0·01 m2 in surface intercepting the current). At the beginning of the sporophytic production cycle (210 days), the meristematic zone produces more tissue for blade growth than for stipe growth. Holdfast growth occurs in the first 3 months. The mortality was 90% for sporophytes 0–10 cm in length, and decreased to ~50% in adult plants. One cohort in the cycle has been identified. The net primary production (calculated by the graphic model of Allen) was 0·04 g dry weight m-2·day-1 from April to October (210 days). The production is among the lowest values estimated for seaweeds. 相似文献
963.
Three Replicons of Rhizobium sp. Strain NGR234 Harbor Symbiotic Gene Sequences 总被引:1,自引:0,他引:1
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Margarita Flores Patrick Mavingui Lourdes Girard Xavier Perret William J. Broughton Esperanza Martínez-Romero Guillermo Dvila Rafael Palacios 《Journal of bacteriology》1998,180(22):6052-6053
Rhizobium sp. strain NGR234 contains three replicons: the symbiotic plasmid or pNGR234a, a megaplasmid (pNGR234b), and the chromosome. Symbiotic gene sequences not present in pNGR234a were analyzed by hybridization. DNA sequences homologous to the genes fixLJKNOPQGHIS were found on the chromosome, while sequences homologous to nodPQ and exoBDFLK were found on pNGR234b. 相似文献
964.
Alexander?K. Buell Peter Hung Xavier Salvatella Mark?E. Welland Christopher?M. Dobson Tuomas?P.J. Knowles 《Biophysical journal》2013,104(5):1116-1126
Electrostatic forces play a key role in mediating interactions between proteins. However, gaining quantitative insights into the complex effects of electrostatics on protein behavior has proved challenging, due to the wide palette of scenarios through which both cations and anions can interact with polypeptide molecules in a specific manner or can result in screening in solution. In this article, we have used a variety of biophysical methods to probe the steady-state kinetics of fibrillar protein self-assembly in a highly quantitative manner to detect how it is modulated by changes in solution ionic strength. Due to the exponential modulation of the reaction rate by electrostatic forces, this reaction represents an exquisitely sensitive probe of these effects in protein-protein interactions. Our approach, which involves a combination of experimental kinetic measurements and theoretical analysis, reveals a hierarchy of electrostatic effects that control protein aggregation. Furthermore, our results provide a highly sensitive method for the estimation of the magnitude of binding of a variety of ions to protein molecules. 相似文献
965.
966.
Manuel Gargallo Fernández Julio Basulto Marset Irene Breton Lesmes Joan Quiles Izquierdo Xavier Formiguera Sala Jordi Salas-Salvadó 《Endocrinología y nutrición》2012,59(7):429-437
This paper is a summary of the Spanish Federation of Nutrition, Food and Dietetics Associations (FESNAD) and the Spanish Association for the Study of Obesity (SEEDO) consensus document on the role of diet in prevention and treatment of overweight and obesity.To prepare this document, and in order to achieve the maximum evidence level possible, a systematic review was made of all medical literature published between January 1, 1996 and January 31, 2011 (15 years). The obtained findings were catalogued by evidence level following the Scottish Intercollegiate Guidelines Network system, and recommendations were produced based on data collected.As a result, 65 evidences and 31 recommendations applicable to obese adults without any other pathological process were produced.Evidences and resulting recommendations are provided, and the most significant findings are discussed.This consensus document is intended to provide healthcare professionals with a reference tool that may help them design dietary strategies for prevention and treatment of overweight and obesity. 相似文献
967.
Mona Hedreville Keyne Charlot Xavier Waltz Stéphane Sinnapah Nathalie Lemonne Maryse Etienne-Julan Valérie Soter Olivier Hue Marie-Dominique Hardy-Dessources Jean-Claude Barthélémy Philippe Connes 《PloS one》2014,9(4)
A decreased global autonomic nervous system (ANS) activity and increased sympathetic activation in patients with sickle cell anemia (SCA) seem to worsen the clinical severity and could play a role in the pathophysiology of the disease, notably by triggering vaso-occlusive crises. Because exercise challenges the ANS activity in the general population, we sought to determine whether a short (<15 min) and progressive moderate exercise session conducted until the first ventilatory threshold had an effect on the ANS activity of a group of SCA patients and a group of healthy individuals (CONT group). Temporal and spectral analyses of the nocturnal heart rate variability were performed before and on the 3 nights following the exercise session. Standard deviation of all normal RR intervals (SDNN), total power, low frequencies (LF) and high frequencies powers (HF) were lower but LF/HF was higher in SCA patients than in the CONT group. Moderate exercise did not modify ANS activity in both groups. In addition, no adverse clinical events occurred during the entire protocol. These results imply that this kind of short and moderate exercise is not detrimental for SCA patients. 相似文献
968.
Juan J. Vergara J. Lucas Prez-Llorns Gloria Peralta Ignacio Hernndez F. Xavier Niell 《Journal of phycology》1997,33(5):773-779
The primary production of Ulva populations relies on their photosynthetic performance, which is dependent on the light availability under natural conditions. This study concerns the light attenuation characteristics in Ulva canopies and the seasonal photosynthetic performance of two different species (Ulva rotundata Blid., Ulva curvata (Kütz.) De Toni) blooming in the Palmones river estuary. Light within canopies differed from that reaching the surface. Light availability was reduced through the water column (at high tide) and Ulva canopies. In addition, light was spectrally filtered. As a result, the photosynthetically usable radiation (PUR) was further attenuated through Ulva canopies, increasing the photosynthetically active radiation/PUR ratio. The muddy sediment deposited on and between the Ulva thalli also drastically restricted the light availability. Thick Ulva mats are frequently found covering the intertidal mudflats, and therefore, thalli within these mats may be subjected to steep light gradients. As a consequence, individual Ulva growth rates cannot be extrapolated to estimate the primary production of Ulva canopies. Interspecific differences were observed for light-saturated photosynthetic rates (Pmax) and light compensation points (LCP), with Ulva curvata generally displaying higher values than did U. rotundata. For both species, maxima were recorded in winter for Pmax, quantum yield, chlorophyll content, and absorptance, whereas minima were found in summer. Dark respiration (Rd) was not seasonally affected, and a maximum LCP was found in summer. To extrapolate these data to field situations, the temperature dependence of photosynthesis should be considered. The Q10 values were 2.44 for Rd and 1.79 for Pmax, whereas the photosynthesis rate at subsaturating light levels was unaffected. The Q10 values showed an enhanced respiratory rate in summer and a minimum in winter, whereas the seasonal differences on Pmax were damped. 相似文献
969.
Hydrobiologia - A large spatial heterogeneity was detected in La Safor, a coastal area with different kinds of small and shallow water bodies. The area exhibits a sharp gradient in eutrophication... 相似文献
970.