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101.
Associations between δ13C values and leaf gas exchanges and tree-ring or needle growth, used in ecophysiological compositions, can be complex depending
on the relative timing of CO2 uptake and subsequent redistribution and allocation of carbon to needle and stem components. For palaeoenvironmental and
dendroecological studies it is often interpreted in terms of a simple model of δ13C fractionation in C3 plants. However, in spite of potential complicating factors, few studies have actually examined these relationships in mature
trees over inter- and intra-annual time-scales. Here, we present results from a 4 years study that investigated the links
between variations in leaf gas-exchange properties, growth, and dated δ13C values along the needles and across tree rings of Aleppo pine trees growing in a semi-arid region under natural conditions
or with supplemental summer irrigation. Sub-sections of tissue across annual rings and along needles, for which time of formation
was resolved from growth rate analyses, showed rapid growth and δ13C responses to changing environmental conditions. Seasonal cycles of growth and δ13C (up to ~4‰) significantly correlated (P<0.01) with photosynthetically active radiation, vapour pressure deficit, air temperature, and soil water content. The irrigation
significantly increased leaf net assimilation, stomatal conductance and needle and tree-ring growth rate, and markedly decreased
needle and tree-ring δ13C values and its sensitivity to environmental parameters. The δ13C estimates derived from gas-exchange parameters, and weighted by assimilation, compared closely with seasonal and inter-annual
δ13C values of needle- and tree-ring tissue. Higher stomatal conductances of the irrigated trees (0.22 vs. 0.08 mol m−2 s−1 on average) corresponded with ~2.0‰ lower average δ13C values, both measured and derived. Derived and measured δ13C values also indicated that needle growth, which occurs throughout the stressful summer was supported by carbon from concurrent,
low rate assimilation. For Aleppo pine under semi-arid and irrigated conditions, the δ13C of tree-ring and needle material proved, in general, to be a reasonable indicator of integrated leaf gas-exchange properties. 相似文献
102.
103.
Pere P. Simarro Giuliano Cecchi José R. Franco Massimo Paone Abdoulaye Diarra José Antonio Ruiz-Postigo Eric M. Fèvre Raffaele C. Mattioli Jean G. Jannin 《PLoS neglected tropical diseases》2012,6(10)
Background
Human African trypanosomiasis (HAT), also known as sleeping sickness, persists as a public health problem in several sub-Saharan countries. Evidence-based, spatially explicit estimates of population at risk are needed to inform planning and implementation of field interventions, monitor disease trends, raise awareness and support advocacy. Comprehensive, geo-referenced epidemiological records from HAT-affected countries were combined with human population layers to map five categories of risk, ranging from “very high” to “very low,” and to estimate the corresponding at-risk population.Results
Approximately 70 million people distributed over a surface of 1.55 million km2 are estimated to be at different levels of risk of contracting HAT. Trypanosoma brucei gambiense accounts for 82.2% of the population at risk, the remaining 17.8% being at risk of infection from T. b. rhodesiense. Twenty-one million people live in areas classified as moderate to very high risk, where more than 1 HAT case per 10,000 inhabitants per annum is reported.Discussion
Updated estimates of the population at risk of sleeping sickness were made, based on quantitative information on the reported cases and the geographic distribution of human population. Due to substantial methodological differences, it is not possible to make direct comparisons with previous figures for at-risk population. By contrast, it will be possible to explore trends in the future. The presented maps of different HAT risk levels will help to develop site-specific strategies for control and surveillance, and to monitor progress achieved by ongoing efforts aimed at the elimination of sleeping sickness. 相似文献104.
María José Arauz Valéry Ridde Libia Milena Hernández Yaneth Charris Mabel Carabali Luis ángel Villar 《PloS one》2015,10(2)
BackgroundDengue fever is a public health problem in the tropical and sub-tropical world. Dengue cases have grown dramatically in recent years as well as dengue mortality. Colombia has experienced periodic dengue outbreaks with numerous dengue related-deaths, where the Santander department has been particularly affected. Although social determinants of health (SDH) shape health outcomes, including mortality, it is not yet understood how these affect dengue mortality. The aim of this pilot study was to develop and pre-test a social autopsy (SA) tool for dengue mortality.ConclusionsThe SA tool is based on the scientific literature, a validated conceptual framework, researchers’ and health professionals’ expertise, and a pilot study. It is the first time that a SA tool has been created for the dengue mortality context. Our work furthers the study on SDH and how these are applied to neglected tropical diseases, like dengue. This tool could be integrated in surveillance systems to provide complementary information on the modifiable and avoidable death-related factors and therefore, be able to formulate interventions for dengue mortality reduction. 相似文献
105.
Luiz Henrique Soares de Andrade Wilson Max Almeida Monteiro de Moraes Eduardo Hiroshi Matsuo Junior Elizabeth de Orleans Carvalho de Moura Hanna Karen Moreira Antunes Jairo Montemor Ednei Luiz Antonio Danilo Sales Bocalini Andrey Jorge Serra Paulo José Ferreira Tucci Patricia Chakur Brum Alessandra Medeiros 《Molecular and cellular biochemistry》2015,402(1-2):193-202
106.
de María PD Sánchez-Montero JM Alcántara AR Valero F Sinisterra JV 《Biotechnology letters》2005,27(7):499-503
Candida rugosa was cultured using different inducers (oleic acid, olive oil, sunflower oil, n-dodecanol and glycerol) as the only carbon source in batch conditions, as well as in several fed-batch fermentations (oleic acid as inducer) at variable feed rate conditions. The N-terminal analysis of each crude lipase revealed that, while the isoenzymes Lip2 and Lip3 are always secreted (at different proportions depending on the inducer), Lip1 was produced only using n-dodecanol (batch conditions) or oleic acid (fed-batch at high feed rate). The nature of the inducer controls the isoenzyme percentage; when this is fixed, as well as the feed rate in fed-batch fermentation, the isoenzymatic profile remained unaltered and the samples differed only in the activity of the lipases, as determined by heptyl oleate synthesis. 相似文献
107.
Abscisic acid and 14-3-3 proteins control K channel activity in barley embryonic root 总被引:1,自引:0,他引:1
van den Wijngaard PW Sinnige MP Roobeek I Reumer A Schoonheim PJ Mol JN Wang M De Boer AH 《The Plant journal : for cell and molecular biology》2005,41(1):43-55
Germination of seeds proceeds in general in two phases, an initial imbibition phase and a subsequent growth phase. In grasses like barley, the latter phase is evident as the emergence of the embryonic root (radicle). The hormone abscisic acid (ABA) inhibits germination because it prevents the embryo from entering and completing the growth phase. Genetic and physiological studies have identified many steps in the ABA signal transduction cascade, but how it prevents radicle elongation is still not clear. For elongation growth to proceed, uptake of osmotically active substances (mainly K(+)) is essential. Therefore, we have addressed the question of how the activity of K(+) permeable ion channels in the plasma membrane of radicle cells is regulated under conditions of slow (+ABA) and rapid germination (+fusicoccin). We found that ABA arrests radicle growth, inhibits net K(+) uptake and reduces the activity of K(+) (in) channels as measured with the patch-clamp technique. In contrast, fusicoccin (FC), a well-known stimulator of germination, stimulates radicle growth, net K(+) uptake and reduces the activity of K(+) (out) channels. Both types of channels are under the control of 14-3-3 proteins, known as integral components of signal transduction pathways and instrumental in FC action. Intriguingly, 14-3-3 affected both channels in an opposite fashion: whereas K(+) (in) channel activity was fully dependent upon 14-3-3 proteins, K(+) (out) channel activity was reduced by 14-3-3 proteins by 60%. Together with previous data showing that 14-3-3 proteins control the activity of the plasma membrane H(+)-ATPase, this makes 14-3-3 a prime candidate for molecular master regulator of the cellular osmo-pump. Regulation of the osmo-pump activity by ABA and FC is an important mechanism in controlling the growth of the embryonic root during seed germination. 相似文献
108.
Nobre V Serufo JC Carvalho Odos S Mendonça CL Santos SG Mota EM Gomes D Braga E Antunes CM Lenzi HL Lambertucci JR 《Memórias do Instituto Oswaldo Cruz》2004,99(7):717-720
The association between worm infections and bacterial diseases has only recently been emphasized. This study examined the effect of experimental Angiostrongylus costaricensis infection on endogenous intestinal flora of Swiss Webster mice. Eight mice aging six weeks were selected for this experiment. Four were infected with A. costaricensis and the other four were used as controls. Twenty eight days after the worm infection, all mice in both groups were sacrificed and samples of the contents of the ileum and colon were obtained and cultured for aerobic and anaerobic bacteria. In the mice infected with A. costaricensis there was a significant increase in the number of bacteria of the endogenous intestinal flora, accompanied by a decrease in the number of Peptostreptococcus spp. This alteration in the intestinal flora of mice infected by the nematode may help to understand some bacterial infections described in humans. 相似文献
109.
Antônia E.A. Oliveira Elane S. Ribeiro Maura da Cunha Valdirene M. Gomes Kátia V.S. Fernandes José Xavier-Filho 《Plant Growth Regulation》2004,43(1):57-62
Insulin is a 6 kDa peptide hormone that activates several metabolic processes and cellular growth. Germination studies showed that insulin, vanadyl sulphate (an insulin mimetic compound), tyrphostin (an inhibitor of insulin receptor kinase activity), pinitol (a chiro inositol analogue) and glucose were able to accelerate Canavalia ensiformis (Jack bean) seedling radicle and epicotyl development. Immunofluorescence microscopy analysis showed that proteins binding to insulin, insulin receptor and phosphoserine antibodies are localized in an internal layer of the C. ensiformis seed coat. These results and others previously reported from our laboratory suggest that insulin, insulin receptor and phosphoserine proteins could be components of signalling pathways akin to those present in animals. 相似文献
110.
Hoffman SM Tully JE Lahue KG Anathy V Nolin JD Guala AS van der Velden JL Ho YS Aliyeva M Daphtary N Lundblad LK Irvin CG Janssen-Heininger YM 《American journal of physiology. Lung cellular and molecular physiology》2012,303(6):L528-L538
Protein-S-glutathionylation (PSSG) is an oxidative modification of reactive cysteines that has emerged as an important player in pathophysiological processes. Under physiological conditions, the thiol transferase, glutaredoxin-1 (Glrx1) catalyses deglutathionylation. Although we previously demonstrated that Glrx1 expression is increased in mice with allergic inflammation, the impact of Glrx1/PSSG in the development of allergic airways disease remains unknown. In the present study we examined the impact of genetic ablation of Glrx1 in the pathogenesis of allergic inflammation and airway hyperresponsiveness (AHR) in mice. Glrx1(-/-) or WT mice were subjected to the antigen, ovalbumin (OVA), and parameters of allergic airways disease were evaluated 48 h after three challenges, and 48 h or 7 days after six challenges with aerosolized antigen. Although no clear increases in PSSG were observed in WT mice in response to OVA, marked increases were detected in lung tissue of mice lacking Glrx1 48 h following six antigen challenges. Inflammation and expression of proinflammatory mediators were decreased in Glrx1(-/-) mice, dependent on the time of analysis. WT and Glrx1(-/-) mice demonstrated comparable increases in AHR 48 h after three or six challenges with OVA. However, 7 days postcessation of six challenges, parameters of AHR in Glrx1(-/-) mice were resolved to control levels, accompanied by marked decreases in mucus metaplasia and expression of Muc5AC and GOB5. These results demonstrate that the Glrx1/S-glutathionylation redox status in mice is a critical regulator of AHR, suggesting that avenues to increase S-glutathionylation of specific target proteins may be beneficial to attenuate AHR. 相似文献