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1.
Plant Physiol ; 194(2): 1059-1074, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-37787609

RESUMO

Plants have evolved photosynthetic regulatory mechanisms to maintain homeostasis in response to light changes during diurnal transitions and those caused by passing clouds or by wind. One such adaptation directs photosynthetic electron flow to a cyclic pathway to alleviate excess energy surges. Here, we assign a function to regulatory cysteines of PGR5-like protein 1A (PGRL1A), a constituent of the PROTON GRADIENT REGULATION5 (PGR5)-dependent cyclic electron flow (CEF) pathway. During step increases from darkness to low light intensity in Arabidopsis (Arabidopsis thaliana), the intermolecular disulfide of the PGRL1A 59-kDa complex was reduced transiently within seconds to the 28-kDa form. In contrast, step increases from darkness to high light stimulated a stable, partially reduced redox state in PGRL1A. Mutations of 2 cysteines in PGRL1A, Cys82 and Cys183, resulted in a constitutively pseudo-reduced state. The mutant displayed higher proton motive force (PMF) and nonphotochemical quenching (NPQ) than the wild type (WT) and showed altered donor and acceptor dynamic flow around PSI. These changes were found to correspond with the redox state of PGRL1A. Continuous light regimes did not affect mutant growth compared to the WT. However, under fluctuating regimes of high light, the mutant showed better growth than the WT. In contrast, in fluctuating regimes of low light, the mutant displayed a growth penalty that can be attributed to constant stimulation of CEF under low light. Treatment with photosynthetic inhibitors indicated that PGRL1A redox state control depends on the penultimate Fd redox state. Our results showed that redox state changes in PGRL1A are crucial to optimize photosynthesis.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Complexo de Proteínas do Centro de Reação Fotossintética , Prótons , Transporte de Elétrons , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Fotossíntese/fisiologia , Oxirredução , Luz , Arabidopsis/metabolismo , Complexo de Proteínas do Centro de Reação Fotossintética/genética , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo
2.
Plant Cell Environ ; 46(8): 2542-2557, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37212197

RESUMO

The Cercospora species of fungi are responsible for leaf spot disease affecting many key economic crops. Most of these fungi secrete a toxic photodynamic molecule, cercosporin, that reacts with light and oxygen to produce reactive singlet oxygen (1 O2 ) contributing to fungal virulence. We show similar cellular localization and aetiology of cercosporin in the non-host Arabidopsis and the host Nicotiana benthamiana. Cercosporin accumulates in cell membranes in an oxidized state and in plastids in a mixture of redox states in a manner that is dependent on ongoing photosynthetic processes. We observed that cercosporin rapidly compromised photosynthesis as measured by Fv /Fm , NPQ, and photosystem I (PSI) parameters. Stomatal guard cells in particular demonstrated rapid light-dependent membrane permeabilization that led to changes in leaf conductance. We showed that cercosporin-mediated 1 O2 generation oxidized RNA to form 8-oxoguanosine (8-oxoG), leading to translational attenuation and induction of 1 O2 signature gene transcripts. We also identified a subset of cercosporin-induced transcripts that were independent of the photodynamic effect. Our results point to the multimodal action of cercosporin that includes the inhibition of photosynthesis, the direct oxidation of nucleic acid residues and the elicitation of complex transcriptome responses.


Assuntos
Ascomicetos , Micotoxinas , Micotoxinas/metabolismo , Oxigênio Singlete/metabolismo , Oxigênio/metabolismo
3.
Artigo em Inglês | MEDLINE | ID: mdl-35839174

RESUMO

High-performance cobalt (Co) nanoparticles supported on a zeolite-graphene oxide (1:2) matrix (catalyst Z2) are synthesized through a facile reduction method. In multipoint Brunauer-Emmett-Teller (MBET) surface area analysis, catalyst Z2 demonstrates a higher surface area compared with other synthesized catalysts, indicating the presence of a larger number of catalytic active sites, and supports outstanding ORR performance due to an improved electron-transfer rate and a higher number of redox-active sites. Furthermore, it is observed that catalyst Z2 is an excellent electrocatalytic material due to its low charge-transfer resistance and higher oxygen reduction reaction (ORR) activity. Herein, the electrocatalytic investigation suggests that catalyst Z2 at a potential of 483 mV and a reduction current of -0.382 mA displays a higher electrocatalytic performance and higher stability toward ORR compared with other synthesized catalysts and even the standard Pt/C catalyst. Also, when catalyst Z2 is applied as an air-cathode ORR electrocatalyst for a single-chambered microbial fuel cell (SC-MFC), the SC-MFC coated with catalyst Z2 generates the maximum power density of 416.78 mW/m2, which is 306% higher than that of SC-MFC coated with Pt/C (102.67 mW/m2). In fact, the longer stability and electronic conductivity have contributed to an outstanding ORR activity of the nanocomposite due to its porous surface morphology and the presence of the functional groups in the zeolite-GO support matrix. In brief, Co (cobalt) nanoparticles doped on a zeolite-GO (1:2) support matrix are promising cathode electrocatalysts in the practical application of MFCs and other related devices.

4.
Environ Sci Pollut Res Int ; 29(53): 80787-80804, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35729378

RESUMO

Microbial fuel cells (SC-MFCs) have emerged as green energy devices to resolve the growing energy and environmental crisis. However, the technology's application depends on the sluggish oxygen reduction reaction (ORR) kinetics. Among the electrocatalysts explored, transition metal-nitrogen-carbon composites exhibit satisfactory ORR activity. Herein, we investigate the performance of copper-nitrogen-carbon (Cu/NC) electrocatalysts for ORR, highlighting the effect of temperature, role of nitrogen functionalities, and Cu-Nx sites in catalyst performance. Cu/NC-700 demonstrated satisfactory ORR activity with an onset potential of 0.7 V (vs. RHE) and a limiting current density of 3.4 mA cm-2. Cu/NC-700 modified MFC exhibited a maximum power density of 489.2 mW m-2, higher than NC-700 (107.3 mW m-2). These observations could result from synergistic interaction between copper and nitrogen atoms, high density of Cu-Nx sites, and high pyridinic-N content. Moreover, the catalyst exhibited superior stability, implying its use in long-term operations. The electrocatalytic performance of the catalyst suggests that copper-doped carbon catalysts could be potential metal-nitrogen-carbon material for scaled-up MFC applications.


Assuntos
Fontes de Energia Bioelétrica , Nanopartículas , Carbono , Nitrogênio , Cobre , Eletrodos , Oxigênio , Oxirredução
5.
J Cardiol Cases ; 25(5): 292-296, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35582071

RESUMO

Ruptured sinus of Valsalva aneurysm (RSOV) is an uncommon cause of high output heart failure. RSOV most commonly opens into the right ventricle followed by the right atrium and non-coronary cusp involvement is relatively uncommon. Infective endocarditis (IE) is a rare cause of RSOV. We report an interesting clinical scenario of IE causing RSOV managed by device closure. A 16-year-old male patient presented to the emergency department with acute chest pain, fever, and engorged neck veins. On cardiorespiratory system examination he had features of left ventricular failure. Blood culture revealed growth of Staphylococcus aureus. Echocardiography and computed tomography aortography confirmed the diagnosis of 9 mm type IV RSOV (non-coronary cusp to right atrium) with vegetation (5 × 6 mm). The patient refused surgery. When there was no apparent visible vegetation after 6 weeks of antibiotic therapy, we proceeded with 12-mm Amplatzer duct occluder II closure of the anatomical defect. Monthly follow up has been uneventful for 6 months. As per our knowledge this is the first ever reported case of documented definitive IE by S. aureus causing Sakakibara and Konno ruptured Type IV RSOV that has been managed successfully by device closure. .

6.
J Shoulder Elb Arthroplast ; 6: 24715492221075460, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35194567

RESUMO

BACKGROUND: The COVID-19 Pandemic has affected the way health care systems function across the globe. Apart from eliminating the risk of being in a vulnerable environment during the pandemic such as a hospital setting, virtual arthroplasty follow-up reduces the demand on funding and resources on the National Health Services (NHS). METHODS: We retrospectively reviewed our shoulder arthroplasty patients (55) operated between October 2018 to November 2020 at both our hospital sites. For remote follow-up, patients were contacted on a scheduled appointment date via telephone by an orthopaedic surgeon to enquire about their wound, pain and function. Patients were questioned as per questionnaire from the Oxford Shoulder Score (OSS) and American Shoulder and Elbow Surgeons (ASES) Standardised Assessment form. RESULTS: 50 patients were included in the final data set after excluding those who had died (5 patients). All patients had had final x-rays with full Covid-19 precautions at the time of final follow-up. No patient had wound problems except one who had concerns of wound appearance. There were no cases of notching, impingement, deep infection, dislocation or nerve injury. Of the 50 patients, 40 (80%) patients were satisfied to have a remote follow-up. 36 (72%) patients said they wouldn't mind a remote follow-up appointment. CONCLUSION: Remote follow-up via audio consultation may be an effective alternative to in person visits after shoulder arthroplasty. Patients in this series demonstrated a high level of satisfaction with virtual visits and post-operative complications were effectively identified.

7.
Plant J ; 109(3): 585-597, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34767654

RESUMO

Disulfide-based regulation links the activity of numerous chloroplast proteins with photosynthesis-derived redox signals. The plastid terminal oxidase (PTOX) is a thylakoid-bound plastoquinol oxidase that has been implicated in multiple roles in the light and in the dark, which could require different levels of PTOX activity. Here we show that Arabidopsis PTOX contains a conserved C-terminus domain (CTD) with cysteines that evolved progressively following the colonization of the land by plants. Furthermore, the CTD contains a regulatory disulfide that is in the oxidized state in the dark and is rapidly reduced, within 5 min, in low light intensity (1-5 µE m-2 sec-1 ). The reduced PTOX form in the light was reoxidized within 15 min after transition to the dark. Mutation of the cysteines in the CTD prevented the formation of the oxidized form. This resulted in higher levels of reduced plastoquinone when measured at transition to the onset of low light. This is consistent with the reduced state of PTOX exhibiting diminished PTOX oxidase activity under conditions of limiting PQH2 substrate. Our findings suggest that AtPTOX-CTD evolved to provide light-dependent regulation of PTOX activity for the adaptation of plants to terrestrial conditions.


Assuntos
Adaptação Ocular , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Dissulfetos/metabolismo , Oxirredutases/metabolismo , Plastídeos/metabolismo , Oxirredução , Fotossíntese
9.
Gene ; 683: 233-242, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30340051

RESUMO

Salinity is one of the major abiotic stresses which affect plant growth and productivity by imposing dual stress, ionic and osmotic stress, on plants. Halophytes which are adapted to complete their life cycle in saline soil keep the transcript expression of stress-responsive genes constitutively higher in the optimum growth environments, which can be further increased by several folds under stress conditions. The transcript expression of SbNHX1 gene, cloned from a leafless succulent halophyte Salicornia brachiata, was up-regulated under salinity stress, but its transcriptional regulation has not been studied so far. In the present study, a 1727 bp putative promoter (upstream to translation start site) of the SbNHX1 gene was cloned using a genome walking method. The bioinformatics analysis identified important stress-responsive cis-regulatory motifs, GT1, MBS, LTR and ARE, in addition to two leaf-specific enhancer motifs. The GUS expression analysis of stable transgenic tobacco plants, transformed with a transcriptional fusion of GUS with the full SbNHX1 promoter (NP1) or any of its five deletion fragments (NP2 to NP6), showed that the deletion of two enhancer motifs resulted in the sudden decrease in GUS expression in leaves but not in the stem or root tissues. In contrast, under salinity stress, the higher induction of GUS expression observed in NP1 and NP2 was correlated by the presence of salt-inducible GT1- and MBS-motifs which is distributed only in NP1 and NP2 deletion promoter fragments. Finally, we concluded that the SbNHX1 promoter has a 624 bp (-1727 to -1103 bp) regulatory region which contains the two leaf-specific enhancer motifs and salinity stress-inducible GT-1 and MBS motifs. We suggest the SbNHX1 gene promoter and fragments as a candidate alternative promoter/s for crop engineering for better stress tolerance, which can be amended according to the desired level of expression needed.


Assuntos
Chenopodiaceae/genética , Clonagem Molecular/métodos , Trocadores de Sódio-Hidrogênio/genética , Regulação para Cima , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Regiões Promotoras Genéticas , Salinidade , Análise de Sequência de DNA , Estresse Fisiológico
10.
Bioorg Med Chem ; 26(15): 4551-4559, 2018 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-30097361

RESUMO

Arylbenzimidazoles have been synthesized as antimycobacterial agents. An efficient synthesis has been developed for 2-arylbenzimidazoles from o-phenylenediamines and aromatic aldehydes in molecular sieves-methanol system. The methodology is straightforward to get 2-arylbenzimidazoles (3a-3z) in excellent yields with high chemoselectivity over 2-aryl-1-benzylbenzimidazoles (4a-4z). All these benzimidazole analogues were evaluated against M. tuberculosis in BACTEC radiometric assay. The compounds 4y and 4z exhibited potential antitubercular activity against M. tuberculosis H37RV, MIC at 16 µM and 24 µM respectively. The best compound of the series i.e. compound 4y was well tolerated by Swiss-albino mice in acute oral toxicity. Compound 4y possessing a diarylbenzimidazole core, can further be optimized for better activity.


Assuntos
Antituberculosos/síntese química , Imidazóis/química , Mycobacterium tuberculosis/efeitos dos fármacos , Administração Oral , Animais , Antituberculosos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Peso Corporal/efeitos dos fármacos , DNA Girase/química , DNA Girase/metabolismo , Imidazóis/farmacologia , Camundongos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Terciária de Proteína , Relação Estrutura-Atividade
11.
BMJ Case Rep ; 20162016 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-27161204

RESUMO

The clinical spectrum of scrub typhus ranges from mild to fatal depending on the virulence of bacterial strain, susceptibility of the host and promptness with which treatment is started. We report a case of a 14-year-old child with scrub typhus who developed acute pancreatitis. On serological confirmation, doxycycline therapy was started. The patient responded well and had no complications on follow-up. This case report highlights the importance of recognising an uncommon presentation of this common tropical disease, and its prompt diagnosis and early treatment for prevention of serious complications of the condition.


Assuntos
Pancreatite/microbiologia , Tifo por Ácaros/complicações , Adolescente , Antibacterianos/uso terapêutico , Diagnóstico Diferencial , Doxiciclina/uso terapêutico , Feminino , Humanos , Tifo por Ácaros/diagnóstico , Tifo por Ácaros/tratamento farmacológico , Resultado do Tratamento
12.
PLoS One ; 11(2): e0148494, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26885663

RESUMO

Reactive oxygen or nitrogen species are generated in the plant cell during the extreme stress condition, which produces toxic compounds after reacting with the organic molecules. The glutathione-S-transferase (GST) enzymes play a significant role to detoxify these toxins and help in excretion or sequestration of them. In the present study, we have cloned 1023 bp long promoter region of tau class GST from an extreme halophyte Salicornia brachiata and functionally characterized using the transgenic approach in tobacco. Computational analysis revealed the presence of abiotic stress responsive cis-elements like ABRE, MYB, MYC, GATA, GT1 etc., phytohormones, pathogen and wound responsive motifs. Three 5'-deletion constructs of 730 (GP2), 509 (GP3) and 348 bp (GP4) were made from 1023 (GP1) promoter fragment and used for tobacco transformation. The single event transgenic plants showed notable GUS reporter protein expression in the leaf tissues of control as well as treated plants. The expression level of the GUS gradually decreases from GP1 to GP4 in leaf tissues, whereas the highest level of expression was detected with the GP2 construct in root and stem under control condition. The GUS expression was found higher in leaves and stems of salinity or osmotic stress treated transgenic plants than that of the control plants, but, lower in roots. An efficient expression level of GUS in transgenic plants suggests that this promoter can be used for both constitutive as well as stress inducible expression of gene(s). And this property, make it as a potential candidate to be used as an alternative promoter for crop genetic engineering.


Assuntos
Chenopodiaceae/genética , Chenopodiaceae/fisiologia , Glutationa Transferase/genética , Pressão Osmótica , Regiões Promotoras Genéticas , Salinidade , Estresse Fisiológico/genética , Sequência de Bases , Southern Blotting , Chenopodiaceae/efeitos dos fármacos , Chenopodiaceae/enzimologia , Clonagem Molecular , Simulação por Computador , Galactosídeos/metabolismo , Genes de Plantas , Vetores Genéticos/metabolismo , Glucuronidase/metabolismo , Himecromona/análogos & derivados , Himecromona/metabolismo , Dados de Sequência Molecular , Motivos de Nucleotídeos/genética , Plantas Geneticamente Modificadas , Deleção de Sequência , Cloreto de Sódio/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Nicotiana/genética
13.
PLoS One ; 10(7): e0131567, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26158616

RESUMO

The SbASR-1 gene, cloned from a halophyte Salicornia brachiata, encodes a plant-specific hydrophilic and stress responsive protein. The genome of S. brachiata has two paralogs of the SbASR-1 gene (2549 bp), which is comprised of a single intron of 1611 bp, the largest intron of the  abscisic acid stress ripening [ASR] gene family yet reported. In silico analysis of the 843-bp putative promoter revealed the presence of ABA, biotic stress, dehydration, phytohormone, salinity, and sugar responsive cis-regulatory motifs. The SbASR-1 protein belongs to Group 7 LEA protein family with different amino acid composition compared to their glycophytic homologs. Bipartite Nuclear Localization Signal (NLS) was found on the C-terminal end of protein and localization study confirmed that SbASR-1 is a nuclear protein. Furthermore, transgenic groundnut (Arachis hypogaea) plants over-expressing the SbASR-1 gene constitutively showed enhanced salinity and drought stress tolerance in the T1 generation. Leaves of transgenic lines exhibited higher chlorophyll and relative water contents and lower electrolyte leakage, malondialdehyde content, proline, sugars, and starch accumulation under stress treatments than wild-type (Wt) plants. Also, lower accumulation of H2O2 and O2.- radicals was detected in transgenic lines compared to Wt plants under stress conditions. Transcript expression of APX (ascorbate peroxidase) and CAT (catalase) genes were higher in Wt plants, whereas the SOD (superoxide dismutase) transcripts were higher in transgenic lines under stress. Electrophoretic mobility shift assay (EMSA) confirmed that the SbASR-1 protein binds at the consensus sequence (C/G/A)(G/T)CC(C/G)(C/G/A)(A/T). Based on results of the present study, it may be concluded that SbASR-1 enhances the salinity and drought stress tolerance in transgenic groundnut by functioning as a LEA (late embryogenesis abundant) protein and a transcription factor.


Assuntos
Adaptação Fisiológica/genética , Arachis/genética , Chenopodiaceae/genética , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos , Arachis/metabolismo , Ascorbato Peroxidases/genética , Ascorbato Peroxidases/metabolismo , Sequência de Bases , Sítios de Ligação/genética , Catalase/genética , Catalase/metabolismo , Chenopodiaceae/metabolismo , Secas , Eletroforese em Gel de Poliacrilamida , Dosagem de Genes , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio/metabolismo , Microscopia de Fluorescência , Dados de Sequência Molecular , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , Ligação Proteica , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Salinidade , Fatores de Transcrição/metabolismo
14.
Appl Biochem Biotechnol ; 175(1): 436-53, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25308617

RESUMO

Groundnut (Arachis hypogaea L.) is an industrial crop used as a source of edible oil and nutrients. In this study, an efficient method of regeneration and Agrobacterium-mediated genetic transformation is reported for a local cultivar GG-20 using de-embryonated cotyledon explant. A high regeneration 52.69 ± 2.32 % was achieved by this method with 66.6 µM 6-benzylaminopurine (BAP), while the highest number of shoot buds per explant, 17.67 ± 3.51, was found with 20 µM BAP and 10 µM 2,4-dichlorophenoxyacetic acid (2,4-D). The bacterial culture OD, acetosyringone and L-cysteine concentration were optimized as 1.8, 200 µM and 50 mg L(-1), respectively, in co-cultivation media. It was observed that the addition of 2,4-D in co-cultivation media induced accumulation of endogenous indole-3-acetic acid (IAA). The optimized protocol exhibited 85 % transformation efficiency followed by 14.65 ± 1.06 % regeneration, of which 3.82 ± 0.6 % explants were survived on hygromycin after selection. Finally, 14.58 ± 2.95 % shoots (regenerated on survived explants) were rooted on rooting media (RM3). In grafting method, regenerated shoots (after hygromycin selection) were grafted on the non-transformed stocks with 100 % survival and new leaves emerged in 3 weeks. The putative transgenic plants were then confirmed by PCR, Southern hybridization, reverse transcriptase PCR (RT-PCR) and ß-glucuronidase (GUS) histochemical assay. The reported method is efficient and rapid and can also be applied to other crops which are recalcitrant and difficult in rooting.


Assuntos
Agrobacterium/genética , Arachis/genética , Plantas Geneticamente Modificadas , Arachis/crescimento & desenvolvimento , Cotilédone/genética , Cotilédone/crescimento & desenvolvimento , Produtos Agrícolas , Transformação Genética
15.
PLoS One ; 9(10): e111379, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25340650

RESUMO

Heavy metals are common pollutants of the coastal saline area and Salicornia brachiata an extreme halophyte is frequently exposed to various abiotic stresses including heavy metals. The SbMT-2 gene was cloned and transformed to tobacco for the functional validation. Transgenic tobacco lines (L2, L4, L6 and L13) showed significantly enhanced salt (NaCl), osmotic (PEG) and metals (Zn++, Cu++ and Cd++) tolerance compared to WT plants. Transgenic lines did not show any morphological variation and had enhanced growth parameters viz. shoot length, root length, fresh weight and dry weight. High seed germination percentage, chlorophyll content, relative water content, electrolytic leakage and membrane stability index confirmed that transgenic lines performed better under salt (NaCl), osmotic (PEG) and metals (Zn++, Cu++ and Cd++) stress conditions compared to WT plants. Proline, H2O2 and lipid peroxidation (MDA) analyses suggested the role of SbMT-2 in cellular homeostasis and H2O2 detoxification. Furthermore in vivo localization of H2O2 and O2-; and elevated expression of key antioxidant enzyme encoding genes, SOD, POD and APX evident the possible role of SbMT-2 in ROS scavenging/detoxification mechanism. Transgenic lines showed accumulation of Cu++ and Cd++ in root while Zn++ in stem under stress condition. Under control (unstressed) condition, Zn++ was accumulated more in root but accumulation of Zn++ in stem under stress condition suggested that SbMT-2 may involve in the selective translocation of Zn++ from root to stem. This observation was further supported by the up-regulation of zinc transporter encoding genes NtZIP1 and NtHMA-A under metal ion stress condition. The study suggested that SbMT-2 modulates ROS scavenging and is a potential candidate to be used for phytoremediation and imparting stress tolerance.


Assuntos
Chenopodiaceae/genética , Metalotioneína/genética , Nicotiana/fisiologia , Proteínas de Plantas/genética , Espécies Reativas de Oxigênio/química , Clorofila/química , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Germinação , Homeostase , Peróxido de Hidrogênio/química , Íons , Peroxidação de Lipídeos , Metais Pesados/química , Osmose , Oxigênio/química , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Plantas Tolerantes a Sal/genética , Cloreto de Sódio/química , Nicotiana/genética , Transgenes , Água/química
16.
Plant Cell Physiol ; 55(1): 201-17, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24285755

RESUMO

Peroxisomal ascorbate peroxidase detoxifies H2O2 leaching out from peroxisomes into the cytoplasm. The present study describes transcript expression and cis-regulation of the SbpAPX gene cloned from an extreme halophyte, Salicornia brachiata, in the steady state and under different stresses. About 2-fold elevated transcript expression was found in salt- and drought-treated shoots at 12 h compared with control, while 1.9-fold increased expression was observed under heat treatment. In roots, the transcript level was down-regulated at 2 h, thereafter increasing with the time of exposure and reaching a maximum at the control level. The SbpAPX promoter has characteristic cis-regulatory ABA-dependent abiotic stress-responsive elements. The full-length promoter (1,024 bp, PP1) and deletion constructs -838 (PP2), -697 (PP3), -433 (PP4) and -185 bp (PP5) were fused with the GUS (ß-glucuronidase) gene and transformed into tobacco for functional validation. Expression of GUS increased significantly in transgenic plants under stress. Quantitative expression analysis of GUS in T1 plants revealed that promoter PP5 is efficient for gene expression. In planta transient expression further suggested that the promoter PP5 contains efficient stress-inducible elements. A steep decline in GUS expression in PP3, and thereafter an elevated expression in PP4 and PP5, suggested the presence of a repressor element between -696 and -433 bp, while an enhancer element was predicted between -838 and -697 bp. Further, transient expression analyses and electrophoretic mobility shift assay revealed that the core sequence of cis-acting motifs ATAA and CCTCAA function as enhancer and repressor binding sites, respectively. Based on the study, a model is proposed for the cis-regulation of the SbpAPX gene. The present study provides a useful insight for understanding gene expression regulation in a halophyte with or without stress. Furthermore, potential stress-responsive promoter-driven expression of introgressed gene(s) can be used for engineering crops with enhanced stress tolerance.


Assuntos
Ascorbato Peroxidases/genética , Chenopodiaceae/enzimologia , Chenopodiaceae/genética , Genes de Plantas/genética , Peroxissomos/enzimologia , Plantas Tolerantes a Sal/genética , Transcrição Gênica , Ascorbato Peroxidases/metabolismo , Sequência de Bases , Sítios de Ligação , Clonagem Molecular , Simulação por Computador , Secas , Elementos Facilitadores Genéticos/genética , Regulação da Expressão Gênica de Plantas , Genes Reporter , Glucuronidase/metabolismo , Temperatura Alta , Modelos Biológicos , Dados de Sequência Molecular , Raízes de Plantas/genética , Brotos de Planta/genética , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Repressoras/metabolismo , Estresse Fisiológico/genética , Transformação Genética
17.
J Steroid Biochem Mol Biol ; 137: 332-44, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23459143

RESUMO

Combretastatin A4 analogues were synthesized on steroidal framework from gallic acid with a possibility of anti-breast cancer agents. Twenty two analogues were synthesized and evaluated for cytotoxicity against human breast cancer cell lines (MCF-7 & MDA-MB 231). The best analogue 22 showed potent antitubulin effect. Docking experiments also supported strong binding affinity of 22 to microtubule polymerase. In cell cycle analysis, 22 induced apoptosis in MCF-7 cells significantly. It was found to be non-toxic up to 300 mg/kg dose in Swiss albino mice in acute oral toxicity. This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".


Assuntos
Neoplasias da Mama/patologia , Esteroides/química , Estilbenos/síntese química , Estilbenos/farmacologia , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Espectroscopia de Ressonância Magnética , Camundongos , Ratos , Ratos Sprague-Dawley , Espectrometria de Massas por Ionização por Electrospray , Estilbenos/química
18.
Org Biomol Chem ; 10(46): 9148-51, 2012 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-23108537

RESUMO

A quick, efficient, one-pot method for the synthesis of substituted N-aryl lactams through the reaction of various kinds of corresponding substituted arenes with a variety of ω-azido alkanoic acid chlorides using a Lewis acid (i.e. EtAlCl(2)) at room temperature, through the in situ involvement of a Friedel-Crafts reaction followed by intramolecular Schimdt rearrangement was developed, and afforded good to excellent yields.


Assuntos
Ácidos Carboxílicos/química , Lactamas/síntese química , Ácidos de Lewis/química , Compostos Macrocíclicos/química , Catálise , Cloretos , Estrutura Molecular , Estereoisomerismo , Temperatura
19.
Steroids ; 77(8-9): 878-86, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22503714

RESUMO

Phenstatin analogues were synthesized on steroidal framework, for selective targeting of breast cancer cells. These analogues were evaluated for anticancer efficacy against breast cancer cell lines. Analogues 12 and 19 exhibited significant anticancer activity against MCF-7, hormone dependent breast cancer cell line. While analogues 10-14 exhibited significant anticancer activity against MDA-MB-231, hormone independent breast cancer cell line. Compound 10 showed significant oestrogen antagonistic activities with low agonistic activity in in vivo rat model. These analogues also retain tubulin polymerization inhibition activity. The most active analogue 10 was found to be non-toxic in Swiss albino mice up to 300 mg/kg dose. Gallic acid based phenstatin analogues may further be optimized as selective anti-breast cancer agents.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Ácido Gálico/química , Polimerização/efeitos dos fármacos , Tubulina (Proteína)/metabolismo , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Ratos , Ratos Sprague-Dawley
20.
Gene ; 499(2): 280-7, 2012 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-22441126

RESUMO

Salicornia brachiata is an extreme halophyte growing luxuriantly in the coastal marshes and frequently exposed to various abiotic stresses including heavy metals. A full length type 2 metallothionein (SbMT-2) gene was isolated using RACE and its copy number was confirmed by southern blot analysis. Transcript expression of SbMT-2 gene was analyzed by semi-quantitative Rt-PCR and real time quantitative (qRT) PCR. Expression of SbMT-2 gene was up-regulated concurrently with zinc, copper, salt, heat and drought stress, down regulated by cold stress while unaffected under cadmium stress. Heterologous expression of SbMT-2 gene enhances metal accumulation and tolerance in E. coli. Metal-binding characteristics of SbMT-2 protein show its possible role in homeostasis and/or detoxification of heavy metals. Significant tolerance was observed by E. coli cells expressing recombinant SbMT-2 for Zn(++), Cu(++) and Cd(++) compared to cells expressing GST only. Sequestration of zinc was 4-fold higher compared to copper and in contrast SbMT-2 inhibits the relative accumulation of cadmium by 1.23-fold compared to GST protein. Fusion protein SbMT-2 showed utmost affinity to zinc (approx. 2.5 fold to Cu(++) and Cd(++)) followed by copper and cadmium ions with same affinity. Halophyte S. brachiata has inherent resilience of varying abiotic tolerance therefore SbMT-2 gene could be a potential candidate to be used for enhanced metal tolerance and heavy metal phytoremediation.


Assuntos
Chenopodiaceae/genética , Escherichia coli/genética , Metalotioneína/genética , Proteínas de Plantas/metabolismo , Sequência de Aminoácidos , Chenopodiaceae/fisiologia , Clonagem Molecular , Expressão Gênica , Metalotioneína/química , Metalotioneína/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas Tolerantes a Sal/genética
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