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1.
J Comput Chem ; 45(13): 1008-1016, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38205659

RESUMO

The structural, optoelectronics, and transport properties of TlTaO3 compounds were determined utilizing the full potential augmented plane wave approach using first-principle method. We have considered the generalized gradient approximation for structural optimization and modified Becke-Johnson for electronic properties. The electronic properties reveal that the studied TlTaO3 possesses direct bandgap of magnitude 1.52 eV. Between 0 and 12 eV, optical spectra calculations are made, taking into account the real and imaginary parts of the dielectric function, refractive index, and loss function. The transport properties are estimated considering Boltzmann transport theory. The Seebeck coefficient, electrical conductivity, thermal conductivity, and power factor are all assessed using the Boltzmann transport theory. The optimized thermoelectric response of the examined TlTaO3 is produced by the improved carrier mobility, which also improves the thermoelectric efficiency of the TlTaO3. The obtained results will act as a theoretical road map for upcoming experimental and commercial TlTaO3 applications.

2.
J Dent Res ; 103(1): 62-70, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37968805

RESUMO

Aging affects the number and function of gamma-delta (γδ) T cells in a tissue-specific manner, modifying the risk for inflammatory disease. These aging-related γδT-cell variations in gingival tissues that could increase the risk for inflammation and periodontal disease remain unknown. Here we sought to identify quantitative and qualitative variations in gingival γδT cells associated with aging that could have an impact in oral immunoinflammatory responses. For this, gingival tissues from young (4 mo) and aged (24 mo) male and female mice were collected and analyzed by flow cytometry. Cell suspensions were stimulated and stained with eFluor450 (cell viability), anti-CD45 (hematopoietic cells), anti-CD3 (lymphocytes), anti-TCRγδ (γδT cells), anti-IL-15rα (cell proliferation), and anti-Notch-3 (senescence marker). Detection of intracellular cytokines IL-17A and interferon γ (IFNγ) was performed. Gingival expression of specific γ- and δ-chains and cytokines was evaluated by quantitative reverse transcription polymerase chain reaction. A significantly higher number of IL-17A-producing γδT cells and IL-17A expression levels were observed in gingival tissues from aged females but not males. Similarly, the number of gingival Notch-3+ γδT cells increased with aging only in females. IL-15rα was not detected in gingival γδT cells. Chains γ1, 2, 4, 5, 6, and 7 as well as δ1, 2, 4, and 6 were detected. Detection levels of all γ chains except γ1 as well as δ1 and δ2 changed with aging in males, females, or both. Interestingly, number of IL-17A-producing conventional T cells similarly increased with aging only in females. Both sexes showed increased IFNγ+ conventional T-cell numbers with aging; however, it reached significance only in females. In conclusion, the number of gingival IL-17A-producing γδT cells and IL-17A expression increase naturally with aging specifically in females. This sexual dimorphism in gingival γδT and conventional Th17 cell numbers and phenotypes suggests distinct aging-related mechanisms of periodontitis in males and females.


Assuntos
Interleucina-17 , Receptores de Antígenos de Linfócitos T gama-delta , Masculino , Feminino , Animais , Camundongos , Interleucina-17/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Citometria de Fluxo , Citocinas , Interferon gama , Envelhecimento , Células Th17
3.
Br J Cancer ; 130(3): 467-475, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38129525

RESUMO

BACKGROUND: Berzosertib (M6620) is a highly potent (IC50 = 19 nM) and selective, first-in-class ataxia telangiectasia-mutated and Rad3-related protein kinase (ATR) inhibitor. This trial assessed the safety, preliminary efficacy, and tolerance of berzosertib in oesophageal cancer (A1 cohort) with RT and advanced solid tumours (A2 cohort) with cisplatin and capecitabine. METHODS: Single-arm, open-label dose-escalation (Time-to-Event Continual Reassessment Method) trial with 16 patients in A1 and 18 in A2. A1 tested six dose levels of berzosertib with RT (35 Gy over 15 fractions in 3 weeks). RESULTS: No dose-limiting toxicities (DLTs) in A1. Eight grade 3 treatment-related AEs occurred in five patients, with rash being the most common. The highest dose (240 mg/m2) was determined as the recommended phase II dose (RP2D) for A1. Seven DLTs in two patients in A2. The RP2D of berzosertib was 140 mg/m2 once weekly. The most common grade ≥3 treatment-related AEs were neutropenia and thrombocytopenia. No treatment-related deaths were reported. CONCLUSIONS: Berzosertib combined with RT is feasible and well tolerated in oesophageal cancer patients at high palliative doses. Berzosertib with cisplatin and capecitabine was well tolerated in advanced cancer. Further investigation is warranted in a phase 2 setting. CLINICAL TRIALS IDENTIFIER: EU Clinical Trials Register (EudraCT) - 2015-003965-27 ClinicalTrials.gov - NCT03641547.


Assuntos
Neoplasias Esofágicas , Isoxazóis , Pirazinas , Humanos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Capecitabina/uso terapêutico , Quimiorradioterapia , Cisplatino/uso terapêutico , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/radioterapia , Isoxazóis/uso terapêutico , Dose Máxima Tolerável , Pirazinas/uso terapêutico
4.
J Phys Condens Matter ; 36(13)2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38061063

RESUMO

The effect of annealing temperature on the microstructure, defects and optical properties of ZnO thin films are investigated using sol-gel based spin coating method for a range of annealing temperatures from 200∘C to 500∘C. The correlation among the microstructure, defects, impurity content and the optical band gap of films of thickness about 10-12 nm is elucidated. The particle size increases and the optical band gap reduces with the annealing temperature. At 200∘C, amorphous films were formed with particle size less than 10 nm with an optical band gap of about 3.41 eV. As the temperature increases the grain size increases and the defect, impurity content as well as the optical band gap reduces. This could be due to the reduction in the lattice strain. For an average grain size of about 35 nm and above, the band gap asymptotically approaches the theoretical value of ZnO (3.37 eV). The photoluminescence (PL) spectra show a systematic red-shift in the excitonic levels corresponding to the variation in the optical band-gap. The defect emission from Zn-vacancies is observed in the PL spectra and are further supported by the positron annihilation measurements.

6.
RSC Adv ; 13(42): 29522-29535, 2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37822649

RESUMO

The structural, magnetic, electronic, elastic, vibrational, optical, thermodynamic as well as thermoelectric properties of newly predicted quaternary LiZrCoX (X = Ge, Sn) Heusler compounds are evaluated intricately with the aid of ab initio techniques developed under the framework of density functional theory. The computed structural properties are found to be in tandem with the existing analogous theoretical and experimental facts. Structural optimization has been carried out in three different structural arrangements, i.e., Type-1, Type-2, and Type-3. Further analysis of the optimization curves reveals that the Type-3 phase, which has the least amount of energy, is the most stable structure for the compounds under consideration. The tabulated cohesive energy and formation energy of these compounds depict their chemical as well as thermodynamic stability. The absence of negative phonon frequencies in the phonon band spectrum of the studied compounds depicts their dynamic stability. Similarly, the tabulated second-order elastic constants (Cij) and the linked elastic moduli show their stability in the cubic phase. The calculated value of Pugh's ratio and Cauchy pressure reveal that LiZrCoGe is brittle whereas LiZrCoSn is ductile. Additionally, the optical characteristics of the compounds are studied in terms of the dielectric function, refractive index, extinction coefficient, absorption coefficient, reflectivity, energy loss function, and optical conductivity. The obtained high value of power factor and figure of merit of the studied lithium-based quaternary compounds predict good thermoelectric behavior in these compounds. Thus, LiZrCoX (X = Ge, Sn) compounds can therefore be used to create innovative and intriguing thermoelectric materials as well as optoelectronic and energy-harvesting equipment.

7.
Res Social Adm Pharm ; 19(11): 1465-1470, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37507339

RESUMO

BACKGROUND: During the pre-vaccine months of the COVID-19 pandemic, pharmacists providing comprehensive medication management to underserved patients with type 2 diabetes mellitus at an urban Federally Qualified Healthcare Center shifted to telephone-based telehealth. OBJECTIVES: This retrospective, observational cohort study evaluated the effectiveness of clinical pharmacist telehealth while identifying associations between patient characteristics and efficacy measures. METHODS: Patients with uncontrolled type 2 diabetes (hemoglobin A1c (HbA1c) ≥ 8%) with a clinical pharmacist visit between April 1 and August 31, 2020, were included. Telehealth effectiveness was measured by the proportions of: 1) patients reached, 2) appointments completed, and 3) the median change in HbA1c from baseline. Interventions by the clinical pharmacist were analyzed as a secondary outcome. RESULTS: There were 181 patients scheduled and 172 (95%) of those patients kept at least one appointment. Of the 667 appointments scheduled, 73% were kept. Median HbA1c was reduced from 10.2% to 9.2% over 5 months of follow-up, and 24.6% of patients achieved a HbA1c < 8% (n = 138, p < 0.0001 for each). Greater HbA1c changes were associated with higher baseline blood glucose (p = 0.01), higher baseline HbA1c (p < 0.0001), non-insulin medications at baseline (p = 0.007) and among those with more kept visits (p = 0.03). The healthcare quality impact of interventions during each appointment was favorable; 83.3% brought care to a higher standard, 1.9% averted major organ dysfunction and 0.4% prevented death. CONCLUSIONS: Clinical pharmacist telehealth was effective for providing patient-centered diabetes care when in-person office visits were not an option.


Assuntos
COVID-19 , Diabetes Mellitus Tipo 2 , Telemedicina , Humanos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Farmacêuticos , Hemoglobinas Glicadas , Estudos Retrospectivos , Populações Vulneráveis , População Urbana , Pandemias
10.
Chaos ; 33(3): 033125, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37003831

RESUMO

We report the first experimental observations of phase switching in a system of three coupled plasma sources. Two of the plasma sources are inductively coupled to each other while the third one is directly coupled to one of them. The coupled system acquires a frequency pulling synchronized state following which a transition occurs to a frequency entrainment state with an increase in the frequency of the directly coupled system. We also observe a sudden jump from a lower to a higher frequency entrainment state and a concomitant phase switching between the oscillations of the two directly coupled sources while the phase difference between the inductively coupled sources remains constant. These experimental findings are established using various diagnostic tools, such as the Fourier spectra, frequency bifurcation plots, Lissajous plots, and Hilbert transforms of the data. The experimental results are qualitatively modeled using three coupled van der Pol equations, in which two of them are environmentally coupled while the third one is directly coupled with one of them.

11.
Health Place ; 80: 102989, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36804681

RESUMO

Mosquito-borne disease presents a significant threat to urban populations, but risk can be uneven across a city due to underlying environmental patterns. Urban residents rely on social and economic processes to control the environment and mediate disease risk, a phenomenon known as everyday governance. We studied how households employed everyday governance of urban infrastructure relevant to mosquito-borne disease in Bengaluru, India to examine if and how inequalities in everyday governance manifest in differences in mosquito control. We found that governance mechanisms differed for water access and mosquitoes. Economic and social capital served different roles for each, influenced by global narratives of water and vector control.


Assuntos
Ecologia , Controle de Mosquitos , Animais , Humanos , Cidades , Características da Família , Abastecimento de Água
12.
Sci Total Environ ; 869: 161753, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36690110

RESUMO

Hygroscopicity of atmospheric aerosol primarily depends on the size and chemical composition of the particle and is important for estimating anthropogenic aerosol radiative forcing. There is limited information exists over the Indian region on size segregated aerosol hygroscopicity (κ) in different seasons. This study presents 'κ' as derived from a Humidified Tandem Differential Mobility Analyzer (HTDMA) over a High Altitude Cloud Physics Laboratory (HACPL) in the Western Ghats, India for more than a year (from May 2019 to May 2020). The average hygroscopicity values of aerosol particles of diameters 32, 50, 75, 110, 150, 210 and 260 nm at 90 % RH condition are 0.19, 0.18, 0.16, 0.17, 0.18, 0.20, 0.21 respectively during the entire observation period. κ was observed to decrease with an increase in size in the Aitken mode regime (32-75 nm) and an increase in the accumulation mode (110-260 nm). Seasonal variation of hygroscopicity for a wide range of particle diameters is reported which is highly demanding as there is a change in the air mass flow pattern in each of the seasons. The diurnal cycle of hygroscopicity showed a prominent peak during the midnight to early morning hours followed by a decrease in the forenoon hours and a secondary peak in the afternoon hours. κ is found to be higher in pre-monsoon compared to winter season as Chl is approximately 3 % higher in pre-monsoon and NH4Cl is highly hygroscopic among the assumed chemical composition. Hygroscopicity derived through chemical speciation observations assuming internal and external mixing of aerosols i.e. κinter and κexter are overestimating as compared to κHTDMA. However, the bias between kexter and kHTDMA is relatively lower as external mixing type of aerosol is evident through the growth factor data sets measured by HTDMA. Utilizing the hygroscopicity measurements available for discrete diameters by HTDMA, a parameterization of hygroscopicity with the dry diameter of sub-micron particles is developed.

13.
Nature ; 614(7949): 659-663, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36623548

RESUMO

Transmission spectroscopy1-3 of exoplanets has revealed signatures of water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres4,5. However, these previous inferences with the Hubble and Spitzer Space Telescopes were hindered by the observations' relatively narrow wavelength range and spectral resolving power, which precluded the unambiguous identification of other chemical species-in particular the primary carbon-bearing molecules6,7. Here we report a broad-wavelength 0.5-5.5 µm atmospheric transmission spectrum of WASP-39b8, a 1,200 K, roughly Saturn-mass, Jupiter-radius exoplanet, measured with the JWST NIRSpec's PRISM mode9 as part of the JWST Transiting Exoplanet Community Early Release Science Team Program10-12. We robustly detect several chemical species at high significance, including Na (19σ), H2O (33σ), CO2 (28σ) and CO (7σ). The non-detection of CH4, combined with a strong CO2 feature, favours atmospheric models with a super-solar atmospheric metallicity. An unanticipated absorption feature at 4 µm is best explained by SO2 (2.7σ), which could be a tracer of atmospheric photochemistry. These observations demonstrate JWST's sensitivity to a rich diversity of exoplanet compositions and chemical processes.

14.
Cell Tissue Res ; 391(1): 173-188, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36271300

RESUMO

Safety concerns associated with foetal bovine serum (FBS) have restricted its translation into clinics. We hypothesised that platelet lysate (PL) can be utilised as a safe alternative to produce serum-free 3D-engineered skin. PL supported a short-term expansion of fibroblasts, with negligible replication-induced senescence and directed epidermal stratification. PL-expanded fibroblasts were phenotypically separated into three subpopulations of CD90+FAP+, CD90+FAP- and CD90-FAP+, based on CD90 (reticular marker) and FAP (papillary marker) expression profile. PL drove the expansion of the intermediate CD90+ FAP+ subpopulation in expense of reticular CD90+FAP-, which may be less fibrotic once grafted. The 3D-engineered skin cultured in PL was analysed by immunofluorescence using specific markers. Detection of ColIV and LMN-511 confirmed basement membrane. K10 confirmed near native differentiation pattern of neo-epidermis. CD29- and K5-positive interfollicular stem cells were also sustained. Transmission and scanning electron microscopies detailed the ultrastructure of the neo-dermis and neo-epidermis. To elucidate the underlying mechanism of the effect of PL on skin maturation, growth factor contents in PL were measured, and TGF-ß1 was identified as one of the most abundant. TGF-ß1 neutralising antibody reduced the number of Ki67-positive proliferative cells, suggesting TGF-ß1 plays a role in skin maturation. Moreover, the 3D-engineered skin was exposed to lucifer yellow on days 1, 3 and 5. Penetration of lucifer yellow into the skin was used as a semi-quantitative measure of improved barrier function over time. Our findings support the concept of PL as a safe and effective serum alternative for bioengineering skin for cell therapies.


Assuntos
Extratos Celulares , Pele , Engenharia Tecidual , Plaquetas/química , Diferenciação Celular , Epiderme , Fibroblastos , Pele/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Extratos Celulares/química , Engenharia Tecidual/métodos
15.
QJM ; 116(1): 47-56, 2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36053197

RESUMO

OBJECTIVES: This study aims to describe the demographic and clinical profile and ascertain the determinants of outcome among hospitalized coronavirus disease 2019 (COVID-19) adult patients enrolled in the National Clinical Registry for COVID-19 (NCRC). METHODS: NCRC is an on-going data collection platform operational in 42 hospitals across India. Data of hospitalized COVID-19 patients enrolled in NCRC between 1st September 2020 to 26th October 2021 were examined. RESULTS: Analysis of 29 509 hospitalized, adult COVID-19 patients [mean (SD) age: 51.1 (16.2) year; male: 18 752 (63.6%)] showed that 15 678 (53.1%) had at least one comorbidity. Among 25 715 (87.1%) symptomatic patients, fever was the commonest symptom (72.3%) followed by shortness of breath (48.9%) and dry cough (45.5%). In-hospital mortality was 14.5% (n = 3957). Adjusted odds of dying were significantly higher in age group ≥60 years, males, with diabetes, chronic kidney diseases, chronic liver disease, malignancy and tuberculosis, presenting with dyspnoea and neurological symptoms. WHO ordinal scale 4 or above at admission carried the highest odds of dying [5.6 (95% CI: 4.6-7.0)]. Patients receiving one [OR: 0.5 (95% CI: 0.4-0.7)] or two doses of anti-SARS CoV-2 vaccine [OR: 0.4 (95% CI: 0.3-0.7)] were protected from in-hospital mortality. CONCLUSIONS: WHO ordinal scale at admission is the most important independent predictor for in-hospital death in COVID-19 patients. Anti-SARS-CoV2 vaccination provides significant protection against mortality.


Assuntos
COVID-19 , Adulto , Humanos , Masculino , Pessoa de Meia-Idade , COVID-19/prevenção & controle , SARS-CoV-2 , Mortalidade Hospitalar , Estudos de Tempo e Movimento , Vacinação , Doença Crônica
16.
Immunohematology ; 38(3): 82-89, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36190199

RESUMO

Autoimmune hemolytic anemia (AIHA) due to warm-reacting IgA autoantibodies is rare. Here, we explored the clinical and immunohematologic characteristics of patients suffering from IgA-associated warm AIHA (WAIHA) and their transfusion management. The 9-year study included 214 patients with WAIHA who were further classified into two groups: (1) IgA-associated WAIHA and (2) non-IgA-associated WAIHA. Clinical and laboratory details were obtained from patient files and the Hospital Information System. All immunohematologic investigations were performed following standard operating procedures and established protocols. Among the 214 patients with WAIHA, 17 (7.9%) belonged to the IgA-associated group; of these, two IgA-only WAIHA cases were found. The mean hemoglobin in this group was 5.58 g/dL, and 15 (88.2%) of these patients received a total of 32 units of packed red blood cell (RBC) transfusions. In vivo hemolytic markers were significantly abnormal in the IgA-associated WAIHA group when compared with the non-IgA group. Secondary WAIHA was found in 11 (64.7%) patients with IgA-associated WAIHA. Patients with IgA-associated WAIHA received more blood transfusions than individuals in the non-IgA group (p = 0.0004). A total of 17 (7.9%) patients with WAIHA experienced adverse events to blood transfusion. Detailed characterization of WAIHA with particular emphasis on IgA-associated and non-IgA-associated WAIHA is essential to evaluate the disease characteristics, access the degree of hemolysis, understand the immunohematologic behaviors of the antibodies, and manage blood transfusions.


Assuntos
Anemia Hemolítica Autoimune , Anemia Hemolítica Autoimune/terapia , Autoanticorpos , Transfusão de Eritrócitos , Hemoglobinas , Hemólise , Humanos
17.
Nat Microbiol ; 7(9): 1337-1347, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35927336

RESUMO

Early development of the microbiome has been shown to affect general health and physical development of the infant and, although some studies have been undertaken in high-income countries, there are few studies from low- and middle-income countries. As part of the BARNARDS study, we examined the rectal microbiota of 2,931 neonates (term used up to 60 d) with clinical signs of sepsis and of 15,217 mothers screening for blaCTX-M-15, blaNDM, blaKPC and blaOXA-48-like genes, which were detected in 56.1%, 18.5%, 0% and 4.1% of neonates' rectal swabs and 47.1%, 4.6%, 0% and 1.6% of mothers' rectal swabs, respectively. Carbapenemase-positive bacteria were identified by MALDI-TOF MS and showed a high diversity of bacterial species (57 distinct species/genera) which exhibited resistance to most of the antibiotics tested. Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae/E. cloacae complex, the most commonly found isolates, were subjected to whole-genome sequencing analysis and revealed close relationships between isolates from different samples, suggesting transmission of bacteria between neonates, and between neonates and mothers. Associations between the carriage of antimicrobial resistance genes (ARGs) and healthcare/environmental factors were identified, and the presence of ARGs was a predictor of neonatal sepsis and adverse birth outcomes.


Assuntos
Microbioma Gastrointestinal , Sepse , Antibacterianos , Países em Desenvolvimento , Resistência Microbiana a Medicamentos , Escherichia coli , Feminino , Humanos , Lactente , Recém-Nascido , Testes de Sensibilidade Microbiana , Mães
18.
Drugs Context ; 112022.
Artigo em Inglês | MEDLINE | ID: mdl-35775071

RESUMO

Due to worldwide increases in obesity and average maternal age, the incidence of gestational diabetes mellitus (GDM) is increasing. The primary treatment of GDM is medical nutrition therapy but approximately 15-30% of individuals need pharmacotherapy to reach blood glucose goals to minimize the adverse consequences of hyperglycaemia. In the past, regular and neutral protamine Hagedorn insulin were the mainstays of pharmacological treatment for GDM due to their well-established safety; however, because they are administered as injections and require strict timing of doses and meals to minimize hypoglycaemia, alternatives are often sought. The research around the treatment of GDM continues to evolve as insulin analogues and oral agents are studied in clinical trials. The short-term and long-term effects of treatment choices on both mothers and progeny are being evaluated, and this narrative review summarizes the current state of information available regarding the treatment of GDM.

19.
Clin Oncol (R Coll Radiol) ; 34(7): e269-e280, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35466013

RESUMO

The SCOPE 2 trial of definitive chemoradiotherapy in oesophageal cancer investigates the benefits of radiotherapy dose escalation and systemic therapy optimisation. The trial opened in 2016. The landscape of oesophageal cancer treatment over the lifetime of this trial has changed significantly and the protocol has evolved to reflect this. However, with the recent results of the Dutch phase III ART DECO study showing no improvement in local control or overall survival with radiotherapy dose escalation in a similar patient group, we sought to determine if the SCOPE 2 trial is still answering the key unanswered questions for oesophageal radiotherapy. Here we discuss the rationale behind the SCOPE 2 trial, outline the trial schema and review current data on dose escalation and outline recommendations for future areas of research.


Assuntos
Quimiorradioterapia , Neoplasias Esofágicas , Neoplasias Esofágicas/diagnóstico por imagem , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/radioterapia , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada
20.
Plant Biol (Stuttg) ; 24(4): 559-568, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35334141

RESUMO

Apart from nitric oxide (NO) and carbon monoxide (CO), hydrogen sulphide (H2 S) has emerged as a potential gasotransmitter that has regulatory roles in root differentiation, proliferation and stress signalling. H2 S metabolism in plants exhibits spatio-temporal differences that are intimately associated with sulphide signalling in the cytosol and other subcellular components, e.g. chloroplast and mitochondria. H2 S biosynthesis in plant organs uses both enzymatic and non-enzymatic pathways. H2 S generation in roots and aerial organs is modulated by developmental phase and changes in environmental stimuli. H2 S has an influential role in root development and in the nodulation process. Studies have revealed that H2 S is a part of the auxin and NO signalling pathways in roots, which induce lateral root formation. At the molecular level, exogenous application of H2 S regulates expression of several transcription factors, viz. LBD (Lateral organ Boundaries Domain), MYB (myeloblastosis) and AP2/ERF (Apetala 2/ Ethylene Response Factor), which stimulate upregulation of PpLBD16 (Lateral organ boundaries domain 16), thereby significantly increasing the number of lateral roots. Concomitantly, H2 S acts as a crucial signalling molecule in roots during various abiotic stresses, e.g. drought, salinity heavy metals (HMs), etc., and augments stress tolerance in plants. Interestingly, extensive crosstalk exists between H2 S, NO, ABA, calcium and ethylene during stress, which escalate plant defence and regulate plant growth and productivity. Hence, the present review will elaborate the role of H2 S in root development, stress alleviation, legume-Rhizobium symbiosis and rhizosphere signalling. The review also examines the mechanism of H2 S-mediated abiotic stress mitigation and cross-talk with other signaling molecules.


Assuntos
Sulfeto de Hidrogênio , Secas , Etilenos/metabolismo , Sulfeto de Hidrogênio/metabolismo , Óxido Nítrico/metabolismo , Raízes de Plantas/metabolismo , Plantas/metabolismo , Estresse Fisiológico
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