52 research outputs found
Use of Persistent Analogs of Abscisic Acid as Palliatives against Salt-stress Induced Damage in Citrus Plants
The effectiveness of several abscisic acid (ABA) analogs as palliatives against salt stress in intact citrus plants has been tested in this work. The effect of ABA, 8Âą-methylene ABA, 8Âą-acetylene ABA, ABA methyl ester, 8Âą-methylene ABA methyl ester, and 8Âą-acetylene ABA methyl ester on citrus responses to salt stress was studied on 2-year-old grafted plants. Leaf abscission, chloride accumulation, ethylene production, and net photosynthetic rate were the parameters used to characterize the performance of plants under stress. Data indicate that 8Âą-methylene ABA was the most effective compound in delaying the deleterious effects of high salinity on citrus plants. Its regular application reduced leaf chloride concentration, ethylene production, and leaf abscission. Furthermore, it delayed the depletion of CO2 assimilation under these adverse conditions. Abscisic acid and 8Âą-acetylene ABA also reduced salt-stress induced injuries in citrus, although to a lower extent. Neither ABA methyl ester nor its 8Âą-C modified analogs showed biological activity in these assays
Effects of salt stress on plant growth, abscisic acid and salicylic acid in own-rooted cultivars of Vitis vinifera L.
Aim of study: In most areas of vineyards worldwide, cultivars are frequently grafted on specific rootstocks to avoid Daktulosphaira vitifoliae pest attack. Nevertheless, the absence of this pest in Canary Islands allowed the chance to conserve and cultivate traditional or new own-rooted genotypes without the requirement of the rootstocks. To investigate the responses of own-rooted genotypes of Vitis vinifera L. to salt stress conditions, âCastellana Negraâ (âCNâ) and âNegramollâ (âNeâ) were used with the aim to characterize their morphological and physiological responses.Area of study: Canary Islands, Spain.Material and methods: The effects of NaCl stress on growth, abscisic acid (ABA), salicylic acid (SA) and proline were assessed in âCNâ and âNeâ under greenhouse conditions.Main results: In âCNâ, the decrease of leaf number in stressed plants was lower and started eleven days later than in âNeâ. Salt stress also reduced stomatal conductance (gs), although such decrease took place earlier in âCNâ than in âNeâ. ABA and SA concentrations in âCNâ leaves were 2-fold higher than those of âNeâ. Salt stress increased leaf ABA and SA content in both genotypes, compared to control. In conclusion, ABA and SA appear to be involved in grapevines responses to salinity and suggest that exogenous SA could be useful to mitigate the stress impacts.Research highlights: âCNâ exhibited a better response than âNeâ through the delay of salt injury establishment, and the dissimilar responses between âCNâ and âNeâ seem to be associated to the higher accumulation of ABA and SA under salt stress
Abscisic acid promotes plant acclimation to the combination of salinity and high light stress
Plants encounter combinations of different abiotic stresses such as salinity (S) and high light (HL). These environmental conditions have a detrimental effect on plant growth and development, posing a threat to agricultural production. Metabolic changes play a crucial role in enabling plants to adapt to fluctuations in their environment. Furthermore, hormones such as abscisic acid (ABA), jasmonic acid (JA) and salicylic acid (SA) have been previously identified as regulators of plant responses to different abiotic stresses. Here we studied the response of Arabidopsis wild type (Col and Ler) plants and mutants impaired in hormone biosynthesis (aba2-11 and aba1-1 in ABA, aos in JA and sid2 in SA) to the combination of S and HL (S + HL). Our findings showed that aba2-11 plants displayed reduced growth, impaired photosystem II (PSII) function, increased leaf damage, and decreased survival compared to Col when subjected to stress combination. However, aos and sid2 mutants did not display significant changes in response to S + HL compared to Col, indicating a key role for ABA in promoting plant tolerance to S + HL and suggesting a marginal role for JA and SA in this process. In addition, we revealed differences in the metabolic response of plants to S + HL compared to S or HL. The analysis of altered metabolic pathways under S + HL suggested that the accumulation of flavonoids is ABA-dependent, whereas the accumulation of branched-chain amino acids (BCAAs) and proline is ABA-independent. Therefore, our study uncovered a key function for ABA in regulating the accumulation of different flavonoids in plants during S + HL.Funding for open access charge: CRUE-Universitat Jaume
Morphological, physiological, and molecular scion traits are determinant for salt-stress tolerance of grafted citrus plants
IntroductionCitrus productivity has been decreasing in the last decade in the Mediterranean basin as a consequence of climate change and the high levels of salinity found in the aquifers. Citrus varieties are cultivated grafted onto a rootstock, which has been reported as responsible for plant tolerance to adverse situations. However, other important factors for stress tolerance relying in the scion have been less studied. The aim of this study was to evaluate the effect of the grafted scion on citrus tolerance to salt stress.MethodsFour different citrus rootstock/scion combinations were subjected to salt stress for 30 days, using Carrizo citrange (CC) or Citrus macrophylla (CM) as rootstocks, and Navelina orange (NA) or Oronules mandarin (OR) as scions. CM-OR was the most tolerant combination, whereas CC-NA was the most sensitive one.Results and discussionOur results support the idea that the rootstock plays an important role in salt stress tolerance, but scion is also crucial. Thus, photosynthesis and transpiration, processes regulated by abscisic acid and jasmonic acid, are determinant of plant performance. These photosynthetic parameters were not affected in plants of the salt-tolerant combination CM-OR, probably due to the lower intoxication with Clâ ions, allowing a better performance of the photosynthetic machinery under stress conditions. The different stomatal density of the two citrus scions used in this work (higher in the sensitive NA in comparison to the tolerant OR) also contributes to the different tolerance of the grafted plants to this adverse condition. Additionally, CsDTX35.1 and CsDTX35.2, genes codifying for Clâ tonoplast transporters, were exclusively overexpressed in plants of the salt-tolerant combination CM-OR, suggesting that these transporters involved in Clâ compartmentalization could be crucial for salt stress tolerance. It is concluded that to improve citrus tolerance to high salinity, it is important that scions have a versatile photosynthetic system, an adequate stomatal density, and a proper modulation of genes coding for Clâ transporters in the tonoplast
Au@16-pH-16/miR-21 mimic nanosystem: An efficient treatment for obesity through browning and thermogenesis induction
Despite the abundance of registered clinical trials worldwide, the availability of effective drugs for obesity treatment is limited due to their associated side effects. Thus, there is growing interest in therapies that stimulate energy expenditure in white adipose tissue. Recently, we demonstrated that the delivery of a miR-21 mimic using JetPEI effectively inhibits weight gain in an obese mouse model by promoting metabolism, browning, and thermogenesis, suggesting the potential of miR-21 mimic as a treatment for obesity. Despite these promising results, the implementation of more advanced delivery system techniques for miR-21 mimic would greatly enhance the advancement of safe and efficient treatment approaches for individuals with obesity in the future. Our objective is to explore whether a new delivery system based on gold nanoparticles and Gemini surfactants (Au@16-ph-16) can replicate the favorable effects of the miR-21 mimic on weight gain, browning, and thermogenesis. We found that dosages as low as 0.2Â ÎŒg miR-21 mimic /animal significantly inhibited weight gain and induced browning and thermogenic parameters. This was evidenced by the upregulation of specific genes and proteins associated with these processes, as well as the biogenesis of beige adipocytes and mitochondria. Significant increases in miR-21 levels were observed in adipose tissue but not in other tissue types. Our data indicates that Au@16-ph-16 could serve as an effective delivery system for miRNA mimics, suggesting its potential suitability for the development of future clinical treatments against obesity.This research was supported by the following grants: This study has been funded by Instituto de Salud Carlos III (ISCIII) through the project PI21/01924 and PI18/00785 and co-funded by the European Union, by the ConsejerĂa de TransformaciĂłn EconĂłmica, Industria, Conocimiento y Universidades-Junta de AndalucĂa and ERDF-EU (PI20-01274) and by University of Sevilla VI PP USO SSGG (2021/00001297). PI-0092â2017 and PI-0235â2021 from Consejeria de Salud (Junta de Andalucia), Spain. S.L. is a recipient of a Plan Andaluz de InvestigaciĂłn, Desarrollo e InnovaciĂłn post-doctoral grant from the ConsejerĂa de EconomĂa, Conocimiento, Empresas y Universidades (DOC-01138). A.M.G. was a recipient of a Plan Propio de InvestigaciĂłn, Transferencia y DivulgaciĂłn CientĂfica postdoctoral grant from University of MĂĄlaga. FJBS, and REBAV-R are under contract with the âNicolas Monardesâ program from the Servicio Andaluz de Salud, ConsejerĂa de Salud y Consumo-Junta de AndalucĂa (RC-0001-2021, RC-0006-2020 and C-0060-2018, respectively. A.V-R. was supported by a grant from the Ministerio de EconomĂa y Competitividad (Proyectos I+D+i para JĂłvenes Investigadores, SAF2014-60649-JIN).Peer reviewe
Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)
Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters.
Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs).
Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001).
Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4
While the increasing availability of global databases on ecological communities has advanced our knowledge
of biodiversity sensitivity to environmental changes,5â7 vast areas of the tropics remain understudied.8â11 In
the American tropics, Amazonia stands out as the worldâs most diverse rainforest and the primary source of
Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13â15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazonâs biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus
crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced
environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian
Amazonia, while identifying the regionâs vulnerability to environmental change. 15%â18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by
2050. This means that unless we take immediate action, we will not be able to establish their current status,
much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio
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