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51.
Fernández-Fernández JM Nobles M Currid A Vázquez E Valverde MA 《American journal of physiology. Cell physiology》2002,283(6):C1705-C1714
The cell regulatory volume decrease (RVD) response triggered by hypotonic solutions is mainly achieved by the coordinated activity of Cl- and K+ channels. We now describe the molecular nature of the K(+) channels involved in the RVD response of the human bronchial epithelial (HBE) cell line 16HBE14o-. These cells, under isotonic conditions, present a K+ current consistent with the activity of maxi K+ channels, confirmed by RT-PCR and Western blot. Single-channel and whole cell maxi K+ currents were readily and reversibly activated following the exposure of HBE cells to a 28% hypotonic solution. Both maxi K+ current activation and RVD response showed calcium dependency, inhibition by TEA, Ba2+, iberiotoxin, and the cationic channel blocker Gd3+ but were insensitive to clofilium, clotrimazole, and apamin. The presence of the recently cloned swelling-activated, Gd3+-sensitive cation channels (TRPV4, also known as OTRPC4, TRP12, or VR-OAC) was detected by RT-PCR in HBE cells. This channel, TRPV4, which senses changes in volume, might provide the pathway for Ca2+ influx under hypotonic solutions and, consequently, for the activation of maxi K+ channels. 相似文献
52.
Simultaneous measurements of chlorophyll (Chl) fluorescence and CO2 assimilation (A) in Vicia faba leaves were taken during the first weeks of growth to evaluate the protective effect of 24-epibrassinolide (EBR) against
damage caused by the application of the herbicide terbutryn (Terb) at pre-emergence. V. faba seeds were incubated for 24 h in EBR solutions (2 × 10−6 or 2 × 10−5 mM) and immediately sown. Terb was applied at recommended doses (1.47 or 1.96 kg ha−1) at pre-emergence. The highest dose of Terb strongly decreased CO2 assimilation, the maximum quantum yield of PSII photochemistry in the dark-adapted state (F
V/F
M), the nonphotochemical quenching (NPQ), and the effective quantum yield (ΔF/F′M) during the first 3–4 weeks after plant emergence. Moreover, Terb increased the basal quantum yield of nonphotochemical processes
(F
0/F
M), the degree of reaction center closure (1 − q
p), and the fraction of light absorbed in PSII antennae that was dissipated via thermal energy dissipation in the antennae
(1 − F′V/F′M). The herbicide also significantly reduced plant growth at the end of the experiment as well as plant length, dry weight,
and number of leaves. The application of EBR to V. faba seeds before sowing strongly diminished the effect of Terb on fluorescence parameters and CO2 assimilation, which recovered 13 days after plant emergence and showed values similar to those of control plants. The protective
effect of EBR on CO2 assimilation was detected at a photosynthetic photon flux density (PFD) of 650 μmol m−2 s−1 and the effect on ΔF/F′M and photosynthetic electron transport (J) was detected under actinic lightings up to 1750 μmol m−2 s−1. The highest dose of EBR also counteracted the decrease in plant growth caused by Terb, and plants registered the same growth
values as controls. 相似文献
53.
Kimani Tabitha Schelling Esther Bett Bernard Ngigi Margaret Randolph Tom Fuhrimann Samuel 《EcoHealth》2016,13(4):729-742
EcoHealth - In controlling Rift Valley fever, public health sector optimises health benefits by considering cost-effective control options. We modelled cost-effectiveness of livestock RVF control... 相似文献
54.
55.
Marie-Elodie Cattin Jessica Wang Jonathan J. Weldrick Cassandra L. Roeske Esther Mak Stephanie L. Thorn Jean N. DaSilva Yibin Wang Aldon J. Lusis Patrick G. Burgon 《The Journal of biological chemistry》2015,290(44):26699-26714
Aging and diseases generally result from tissue inability to maintain homeostasis through adaptation. The adult heart is particularly vulnerable to disequilibrium in homeostasis because its regenerative abilities are limited. Here, we report that MLIP (muscle enriched A-type lamin-interacting protein), a unique protein of unknown function, is required for proper cardiac adaptation. Mlip−/− mice exhibited normal cardiac function despite myocardial metabolic abnormalities and cardiac-specific overactivation of Akt/mTOR pathways. Cardiac-specific MLIP overexpression led to an inhibition of Akt/mTOR, providing evidence of a direct impact of MLIP on these key signaling pathways. Mlip−/− hearts showed an impaired capacity to adapt to stress (isoproterenol-induced hypertrophy), likely because of deregulated Akt/mTOR activity. Genome-wide association studies showed a genetic association between Mlip and early response to cardiac stress, supporting the role of MLIP in cardiac adaptation. Together, these results revealed that MLIP is required for normal myocardial adaptation to stress through integrated regulation of the Akt/mTOR pathways. 相似文献
56.
Angiogenesis is not impaired in connective tissue growth factor (CTGF) knock-out mice. 总被引:3,自引:0,他引:3
Esther J Kuiper Peggy Roestenberg Christoph Ehlken Vincent Lambert Henny Bloys van Treslong-de Groot Karen M Lyons Hans-Jürgen T Agostini Jean-Marie Rakic Ingeborg Klaassen Cornelis J F Van Noorden Roel Goldschmeding Reinier O Schlingemann 《The journal of histochemistry and cytochemistry》2007,55(11):1139-1147
Connective tissue growth factor (CTGF) is a member of the CCN family of growth factors. CTGF is important in scarring, wound healing, and fibrosis. It has also been implicated to play a role in angiogenesis, in addition to vascular endothelial growth factor (VEGF). In the eye, angiogenesis and subsequent fibrosis are the main causes of blindness in conditions such as diabetic retinopathy. We have applied three different models of angiogenesis to homozygous CTGF(-/-) and heterozygous CTGF(+/-) mice to establish involvement of CTGF in neovascularization. CTGF(-/-) mice die around birth. Therefore, embryonic CTGF(-/-), CTGF(+/-), and CTGF(+/+) bone explants were used to study in vitro angiogenesis, and neonatal and mature CTGF(+/-) and CTGF(+/+) mice were used in models of oxygen-induced retinopathy and laser-induced choroidal neovascularization. Angiogenesis in vitro was independent of the CTGF genotype in both the presence and the absence of VEGF. Oxygen-induced vascular pathology in the retina, as determined semi-quantitatively, and laser-induced choroidal neovascularization, as determined quantitatively, were also not affected by the CTGF genotype. Our data show that downregulation of CTGF levels does not affect neovascularization, indicating distinct roles of VEGF and CTGF in angiogenesis and fibrosis in eye conditions. 相似文献
57.
The role of transition metals in paraquat toxicity was studied in cultures of Plasmodium falciparum. We showed that addition of copper led to an enhancement of the plasmodium killing, whereas addition of chelating agents. such as desferrioxamine and diethylenetriamine pentaacetic acid markedly reduced the toxic effects. Parsitized G6PD deficient erythrocytes were more sensitive than parasitized normal eryth-rocytes to copper and to the combination of copper and paraquat. 相似文献
58.
Luykx JJ Bakker SC Lentjes E Boks MP van Geloven N Eijkemans MJ Janson E Strengman E de Lepper AM Westenberg H Klopper KE Hoorn HJ Gelissen HP Jordan J Tolenaar NM van Dongen EP Michel B Abramovic L Horvath S Kappen T Bruins P Keijzers P Borgdorff P Ophoff RA Kahn RS 《PloS one》2012,7(2):e30497
Background
Animal studies have revealed seasonal patterns in cerebrospinal fluid (CSF) monoamine (MA) turnover. In humans, no study had systematically assessed seasonal patterns in CSF MA turnover in a large set of healthy adults.Methodology/Principal Findings
Standardized amounts of CSF were prospectively collected from 223 healthy individuals undergoing spinal anesthesia for minor surgical procedures. The metabolites of serotonin (5-hydroxyindoleacetic acid, 5-HIAA), dopamine (homovanillic acid, HVA) and norepinephrine (3-methoxy-4-hydroxyphenylglycol, MPHG) were measured using high performance liquid chromatography (HPLC). Concentration measurements by sampling and birth dates were modeled using a non-linear quantile cosine function and locally weighted scatterplot smoothing (LOESS, span = 0.75). The cosine model showed a unimodal season of sampling 5-HIAA zenith in April and a nadir in October (p-value of the amplitude of the cosine = 0.00050), with predicted maximum (PCmax) and minimum (PCmin) concentrations of 173 and 108 nmol/L, respectively, implying a 60% increase from trough to peak. Season of birth showed a unimodal 5-HIAA zenith in May and a nadir in November (p = 0.00339; PCmax = 172 and PCmin = 126). The non-parametric LOESS showed a similar pattern to the cosine in both season of sampling and season of birth models, validating the cosine model. A final model including both sampling and birth months demonstrated that both sampling and birth seasons were independent predictors of 5-HIAA concentrations.Conclusion
In subjects without mental illness, 5-HT turnover shows circannual variation by season of sampling as well as season of birth, with peaks in spring and troughs in fall. 相似文献59.
Volodymyr Trotsiuk Florian Hartig Maxime Cailleret Flurin Babst David I. Forrester Andri Baltensweiler Nina Buchmann Harald Bugmann Arthur Gessler Mana Gharun Francesco Minunno Andreas Rigling Brigitte Rohner Jonas Stillhard Esther Thürig Peter Waldner Marco Ferretti Werner Eugster Marcus Schaub 《Global Change Biology》2020,26(4):2463-2476
The response of forest productivity to climate extremes strongly depends on ambient environmental and site conditions. To better understand these relationships at a regional scale, we used nearly 800 observation years from 271 permanent long‐term forest monitoring plots across Switzerland, obtained between 1980 and 2017. We assimilated these data into the 3‐PG forest ecosystem model using Bayesian inference, reducing the bias of model predictions from 14% to 5% for forest stem carbon stocks and from 45% to 9% for stem carbon stock changes. We then estimated the productivity of forests dominated by Picea abies and Fagus sylvatica for the period of 1960–2018, and tested for productivity shifts in response to climate along elevational gradient and in extreme years. Simulated net primary productivity (NPP) decreased with elevation (2.86 ± 0.006 Mg C ha?1 year?1 km?1 for P. abies and 0.93 ± 0.010 Mg C ha?1 year?1 km?1 for F. sylvatica). During warm–dry extremes, simulated NPP for both species increased at higher and decreased at lower elevations, with reductions in NPP of more than 25% for up to 21% of the potential species distribution range in Switzerland. Reduced plant water availability had a stronger effect on NPP than temperature during warm‐dry extremes. Importantly, cold–dry extremes had negative impacts on regional forest NPP comparable to warm–dry extremes. Overall, our calibrated model suggests that the response of forest productivity to climate extremes is more complex than simple shift toward higher elevation. Such robust estimates of NPP are key for increasing our understanding of forests ecosystems carbon dynamics under climate extremes. 相似文献
60.
Drosophila nemo promotes eye specification directed by the retinal determination gene network 下载免费PDF全文
Drosophila nemo (nmo) is the founding member of the Nemo-like kinase (Nlk) family of serine-threonine kinases. Previous work has characterized nmo's role in planar cell polarity during ommatidial patterning. Here we examine an earlier role for nmo in eye formation through interactions with the retinal determination gene network (RDGN). nmo is dynamically expressed in second and third instar eye imaginal discs, suggesting additional roles in patterning of the eyes, ocelli, and antennae. We utilized genetic approaches to investigate Nmo's role in determining eye fate. nmo genetically interacts with the retinal determination factors Eyeless (Ey), Eyes Absent (Eya), and Dachshund (Dac). Loss of nmo rescues ey and eya mutant phenotypes, and heterozygosity for eya modifies the nmo eye phenotype. Reducing nmo also rescues small-eye defects induced by misexpression of ey and eya in early eye development. nmo can potentiate RDGN-mediated eye formation in ectopic eye induction assays. Moreover, elevated Nmo alone can respecify presumptive head cells to an eye fate by inducing ectopic expression of dac and eya. Together, our genetic analyses reveal that nmo promotes normal and ectopic eye development directed by the RDGN. 相似文献