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141.
Involvement of drinking and intestinal sodium absorption in hyponatremic effect of atrial natriuretic peptide in seawater eels 总被引:1,自引:0,他引:1
Atrial natriuretic peptide (ANP) decreases plasma Na+ concentration and promtes seawater (SW) adaptation in eels. The hyponatremia may most probably be caused by increased branchial extrusion of Na+, but the mechanism has not been determined yet. The present study examined initially the effects of ANP on branchial Na+ efflux in vivo using isotopic 22Na. However, the efflux rate was not altered by infusion of a hyponatremic dose of ANP (5 pmol.kg(-1).min(-1)). Therefore, we sought to examine whether the ANP-mediated hyponatremia is caused by a decrease in the uptake of Na+ from the environment. Since a decrease in drinking was highly correlated with a degree of hyponatremia, conscious SW eels were infused with dilute SW into the stomach at a normal drinking rate to offset the antidipsogenic effect of ANP. Under this regimen, the hyponatremic effect of ANP was abolished. Then, we examined the site of Na+ absorption in the alimentary tract by measuring the changes in ion composition of intraluminal fluid along the tract. Since Na+ was absorbed at the esophagus and anterior/middle intestine, a sac was prepared at each site and the effects of ANP were examined in situ in conscious SW eels. ANP infusion did not alter Na+ absorption at the esophagus, but it profoundly reduced the absorption at the intestine. Together with our previous finding that ANP does not alter renal Na+ excretion, we propose that ANP reduces plasma Na+ concentration in SW eels by inhibiting drinking and subsequent absorption of Na+ by the intestine. 相似文献
142.
Lei Sun Pan Li Xiaohui Ju Jian Rao Wenze Huang Lili Ren Shaojun Zhang Tuanlin Xiong Kui Xu Xiaolin Zhou Mingli Gong Eric Miska Qiang Ding Jianwei Wang Qiangfeng Cliff Zhang 《Cell》2021,184(7):1865-1883.e20
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143.
Ecdysone agonist inducible transcription in transgenic tobacco plants 总被引:15,自引:5,他引:10
Alberto Martinez Caroline Sparks Cliff A. Hart John Thompson Ian Jepson 《The Plant journal : for cell and molecular biology》1999,19(1):97-106
A novel chemical-induced gene regulatory system for plants consisting of two molecular components is described. The first, or regulatory, cassette comprises a chimeric receptor composed of the hinge and ligand binding domains of the Heliothis virescens ecdysone receptor and the transactivation domain of the Herpes simplex VP16 protein fused to the DNA binding domain and transactivation of a mammalian glucocorticoid receptor. The second component, a reporter cassette, contains six copies of the glucocorticoid response element (GRE) fused to the minimal 35SCaMV promoter and β-glucuronidase. The system uses a commercially available non-steroidal ecdysone agonist, RH5992 (tebufenozide), as an inducer. Activation of gene expression is shown in both tobacco transient protoplasts and transgenic plants. The response is ligand dependent and is modulated by the change in minimal promoter context. The system is capable of inducing transgene activity up to 420-fold corresponding to 150% of the activity observed with positive controls (35SCaMV:GUS). 相似文献
144.
Peter?Kiraly Ralph?W.?Adams Liladhar?Paudel Mohammadali?Foroozandeh Juan?A.?Aguilar István?Timári Matthew?J.?Cliff Mathias?Nilsson Péter?Sándor Gyula?Batta Jonathan?P.?Waltho Katalin?E.?K?vér Gareth?A.?MorrisEmail author 《Journal of biomolecular NMR》2015,62(1):43-52
Spectral resolution in proton NMR spectroscopy is reduced by the splitting of resonances into multiplets due to the effect of homonuclear scalar couplings. Although these effects are often hidden in protein NMR spectroscopy by low digital resolution and routine apodization, behind the scenes homonuclear scalar couplings increase spectral overcrowding. The possibilities for biomolecular NMR offered by new pure shift NMR methods are illustrated here. Both resolution and sensitivity are improved, without any increase in experiment time. In these experiments, free induction decays are collected in short bursts of data acquisition, with durations short on the timescale of J-evolution, interspersed with suitable refocusing elements. The net effect is real-time (t 2) broadband homodecoupling, suppressing the multiplet structure caused by proton–proton interactions. The key feature of the refocusing elements is that they discriminate between the resonances of active (observed) and passive (coupling partner) spins. This can be achieved either by using band-selective refocusing or by the BIRD element, in both cases accompanied by a nonselective 180° proton pulse. The latter method selects the active spins based on their one-bond heteronuclear J-coupling to 15N, while the former selects a region of the 1H spectrum. Several novel pure shift experiments are presented, and the improvements in resolution and sensitivity they provide are evaluated for representative samples: the N-terminal domain of PGK; ubiquitin; and two mutants of the small antifungal protein PAF. These new experiments, delivering improved sensitivity and resolution, have the potential to replace the current standard HSQC experiments. 相似文献
145.
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147.
Background
Dihydroartemisinin-piperaquine (DP) is increasingly recommended for antimalarial treatment in many endemic countries; however, concerns have been raised over its potential under dosing in young children. We investigated the influence of different dosing schedules on DP''s clinical efficacy.Methods and Findings
A systematic search of the literature was conducted to identify all studies published between 1960 and February 2013, in which patients were enrolled and treated with DP. Principal investigators were approached and invited to share individual patient data with the WorldWide Antimalarial Resistance Network (WWARN). Data were pooled using a standardised methodology. Univariable and multivariable risk factors for parasite recrudescence were identified using a Cox''s regression model with shared frailty across the study sites. Twenty-four published and two unpublished studies (n = 7,072 patients) were included in the analysis. After correcting for reinfection by parasite genotyping, Kaplan–Meier survival estimates were 97.7% (95% CI 97.3%–98.1%) at day 42 and 97.2% (95% CI 96.7%–97.7%) at day 63. Overall 28.6% (979/3,429) of children aged 1 to 5 years received a total dose of piperaquine below 48 mg/kg (the lower limit recommended by WHO); this risk was 2.3–2.9-fold greater compared to that in the other age groups and was associated with reduced efficacy at day 63 (94.4% [95% CI 92.6%–96.2%], p<0.001). After adjusting for confounding factors, the mg/kg dose of piperaquine was found to be a significant predictor for recrudescence, the risk increasing by 13% (95% CI 5.0%–21%) for every 5 mg/kg decrease in dose; p = 0.002. In a multivariable model increasing the target minimum total dose of piperaquine in children aged 1 to 5 years old from 48 mg/kg to 59 mg/kg would halve the risk of treatment failure and cure at least 95% of patients; such an increment was not associated with gastrointestinal toxicity in the ten studies in which this could be assessed.Conclusions
DP demonstrates excellent efficacy in a wide range of transmission settings; however, treatment failure is associated with a lower dose of piperaquine, particularly in young children, suggesting potential for further dose optimisation. Please see later in the article for the Editors'' Summary 相似文献148.
Stephanie A. Hartsel Cecil Chen John Kennedy Allison Bendele Cliff Wright William S. Marshall 《Nucleosides, nucleotides & nucleic acids》2013,32(7-9):1291-1294
Abstract It is well known that adenosine plays an important role in inflammatory processes. A collection of adenosine analogs modified in the base and/or sugar functional moiety have been synthesized and submitted for biological testing. Each purine nucleoside analog was tested for inhibition of endothelial cell activation by various inflammatory stimuli. A number of analogs exhibited potent anti-inflammatory activity. Animal studies have been carried out on AMG002370 which was found to potently inhibit adjuvant induced arthritis in the Lewis rat. 相似文献
149.
Although seagrasses and marine macroalgae (macro‐autotrophs) play critical ecological roles in reef, lagoon, coastal and open‐water ecosystems, their response to ocean acidification (OA) and climate change is not well understood. In this review, we examine marine macro‐autotroph biochemistry and physiology relevant to their response to elevated dissolved inorganic carbon [DIC], carbon dioxide [CO2], and lower carbonate [CO32?] and pH. We also explore the effects of increasing temperature under climate change and the interactions of elevated temperature and [CO2]. Finally, recommendations are made for future research based on this synthesis. A literature review of >100 species revealed that marine macro‐autotroph photosynthesis is overwhelmingly C3 (≥ 85%) with most species capable of utilizing HCO3?; however, most are not saturated at current ocean [DIC]. These results, and the presence of CO2‐only users, lead us to conclude that photosynthetic and growth rates of marine macro‐autotrophs are likely to increase under elevated [CO2] similar to terrestrial C3 species. In the tropics, many species live close to their thermal limits and will have to up‐regulate stress‐response systems to tolerate sublethal temperature exposures with climate change, whereas elevated [CO2] effects on thermal acclimation are unknown. Fundamental linkages between elevated [CO2] and temperature on photorespiration, enzyme systems, carbohydrate production, and calcification dictate the need to consider these two parameters simultaneously. Relevant to calcifiers, elevated [CO2] lowers net calcification and this effect is amplified by high temperature. Although the mechanisms are not clear, OA likely disrupts diffusion and transport systems of H+ and DIC. These fluxes control micro‐environments that promote calcification over dissolution and may be more important than CaCO3 mineralogy in predicting macroalgal responses to OA. Calcareous macroalgae are highly vulnerable to OA, and it is likely that fleshy macroalgae will dominate in a higher CO2 ocean; therefore, it is critical to elucidate the research gaps identified in this review. 相似文献
150.
Kubicek CP Herrera-Estrella A Seidl-Seiboth V Martinez DA Druzhinina IS Thon M Zeilinger S Casas-Flores S Horwitz BA Mukherjee PK Mukherjee M Kredics L Alcaraz LD Aerts A Antal Z Atanasova L Cervantes-Badillo MG Challacombe J Chertkov O McCluskey K Coulpier F Deshpande N von Döhren H Ebbole DJ Esquivel-Naranjo EU Fekete E Flipphi M Glaser F Gómez-Rodríguez EY Gruber S Han C Henrissat B Hermosa R Hernández-Oñate M Karaffa L Kosti I Le Crom S Lindquist E Lucas S Lübeck M Lübeck PS Margeot A 《Genome biology》2011,12(4):R40