RESUMO
BACKGROUND: Camptothecin is a potent anticancer drug used for the treatment of various cancers. OBJECTIVE: The goal of this research investigation was to develop and validate a new stability-indicating HPLC technique for the quantitative assessment of camptothecin in in-house developed mesoporous silica nanoparticles, a novel nanoformulation matrix for the treatment of cancer. METHOD: The Waters Inertsil® HPLC column (C18) was used for the chromatographic separation, with a flow rate of 1 mL/min, a column oven temperature of 40°C, an injection volume of 10 µL, a detection wavelength of 216 nm, and a 10 min runtime overall. An isocratic blend of phosphate buffer (10 mM, pH7.0) and acetonitrile (60:40, v/v) served as the mobile phase. Various stress conditions including acid, alkali, oxidative, photolytic, thermal, and humidity environments were tested for the quantitative estimation of the camptothecin through the proposed method. RESULTS: The results demonstrated that the proposed method is specific (peak purity ≥0.999), accurate (99.69-100.64% w/w), precise (RSD, % <2.0), and sensitive (LOD-0.17 µg and LOQ-0.56 µg) in accordance with ICH guideline Q2 (R1). Any unidentified degradation products did not interfere with the drug's estimation. Furthermore, the current method of analysis has eliminated any excipient interference from the matrix effect caused by the numerous excipients of the formulation matrix. CONCLUSIONS: To quantify camptothecin for routine assay purposes, this research work offers a novel and straightforward HPLC methodology with optimized chromatographic parameters, contributing to the research and development community while ensuring an appropriate and efficient use of the drug through a variety of nanoformulation for cancer treatment. HIGHLIGHTS: The stability-indicating HPLC method was found to be specific and suitable for routine analysis of camptothecin. The absence of any interference from excipients was confirmed by forced degradation studies.
Assuntos
Camptotecina , Nanopartículas , Dióxido de Silício , Cromatografia Líquida de Alta Pressão/métodos , Camptotecina/análise , Camptotecina/química , Dióxido de Silício/química , Nanopartículas/química , Porosidade , Estabilidade de MedicamentosRESUMO
BACKGROUND: Acute limb ischaemia (ALI) is a limb and life-threatening condition with significant morbidity. There are currently no consensus recommendations for the investigative practices to determine the aetiology of ALI presenting without a known aetiology. We undertook a detailed analysis of all investigations performed to identify an underlying precipitant in those with unexplained ALI and formulated a suggested diagnostic algorithm for the evaluation of unexplained ALI. METHODS: ALI cases presenting to a tertiary referral centre over a 3-year period were reviewed, and known aetiologies, and investigations undertaken to determine the underlying aetiology of unexplained ALI were obtained. RESULTS: Unexplained ALI was found in 27 of 222 patients (12%), of which 21 (78%) had a cause for ALI established after further investigations. Six patients had no cause identified despite extensive work-up. Most patients with unexplained ALI had a cardioembolic source identified as the underlying cause (62%), and this included atrial fibrillation, infective endocarditis, cardiac myxoma and intra-cardiac thrombus. Other causes of unexplained ALI were detected by computed tomography (CT) imaging and included newly diagnosed significant atherosclerotic disease (19%), embolism from isolated proximal large vessel thrombus (10%) and metastatic malignancy (10%). There were no cases attributed to inherited thrombophilias, myeloproliferative neoplasms or anti-phospholipid syndrome. CONCLUSION: Among patients with unexplained ALI, the majority had a cardioembolic source highlighting the importance of comprehensive cardiac investigations. A subset of patients had alternative causes identified on CT imaging. These data support the use of a collaborative and integrative diagnostic algorithm in the evaluation of unexplained ALI.
Assuntos
Doenças Vasculares Periféricas , Trombose , Doença Aguda , Extremidades , Humanos , Isquemia/diagnóstico , Isquemia/etiologia , Salvamento de Membro , Estudos Retrospectivos , Fatores de Risco , Trombose/complicações , Resultado do TratamentoRESUMO
BACKGROUND: Primary mycotic aneurysms and prosthetic graft infections are traditionally managed by resection of infected vascular tissue and revascularisation with an extra-anatomical bypass. Long-term patency for this method has been reported to be poor with associated high reinfection and limb amputation rates. The aim of this study was to analyse the outcomes of those patients in our department between 2010 and 2018 whom had revascularisation with in-situ arterial reconstruction using cryopreserved allograft as a conduit. METHODS: The data were retrospectively reviewed and 13 patients were identified. There were five patients with primary mycotic aneurysms and eight patients with prosthetic graft infections, three of which were complicated by aortoenteric fistulae (AEF). RESULTS: There were three peri-operative mortalities (23%) with all three mortalities related to graft re-infection and post-implantation haemorrhage; two of these from uncontrolled bile leaks related to the original AEF with persistent graft contamination. The 10 surviving patients were followed up for a mean duration of 15.8 months with an overall primary graft patency of 89% and no incidence of graft re-infection or aneurysmal degeneration. CONCLUSION: Patients that survived the peri-operative period demonstrated acceptable medium-term allograft durability, with the most favourable outcomes observed in those patients who had arterial infections uncomplicated by AEF. The main barrier to more wide-spread use in our state remains inadequate supply of banked cryopreserved tissue.
Assuntos
Aneurisma Infectado , Implante de Prótese Vascular , Infecções Relacionadas à Prótese , Aloenxertos , Aneurisma Infectado/cirurgia , Prótese Vascular/efeitos adversos , Implante de Prótese Vascular/efeitos adversos , Criopreservação , Humanos , Infecções Relacionadas à Prótese/epidemiologia , Infecções Relacionadas à Prótese/cirurgia , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Polymers are excipients that modify the rate of drug release from pharmaceutical dosage forms. Hydrophilic polymer-based controlled drug delivery system is more advantageous as compared to the conventional delivery system as it reduces the dosing frequency, improves therapeutic efficacy, reduces side-effects, and probably enhances patient compliance. Polyethylene oxide (PEO), a nonionic hydrophilic polymer, is one of the most widely used polymers for extending the drug release. This review mainly focuses on the PEO marketed by, but not limited to, The Dow Chemical Company under the trade name of POLYOXTM. It is commercially available polyethylene oxide polymer existing in various molecular weight and viscosity grades depending upon the application. This study essentially discusses chemistry, physicochemical properties, and the impact of formulation and processing variables on the release of drug from hydrophilic PEO matrix tablets. Moreover, it also summarizes the stability, patents, and regulatory perspectives of POLYOX that can further influence the future developments of controlled release dosage forms.
Assuntos
Sistemas de Liberação de Medicamentos , Excipientes/química , Polietilenoglicóis/química , Administração Oral , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Peso Molecular , Comprimidos , ViscosidadeRESUMO
Recent studies have identified rice (Oryza sativa) as a major dietary source of inorganic arsenic (As) and poses a significant human health risk. The predominant model for plant detoxification of heavy metals is complexation of heavy metals with phytochelatins (PCs), synthesized non-translationally by PC synthase (PCS) and compartmentalized in vacuoles. In this study, in order to restrict As in the rice roots as a detoxification mechanism, a transgenic approach has been followed through expression of phytochelatin synthase, CdPCS1, from Ceratophyllum demersum, an aquatic As-accumulator plant. CdPCS1 expressing rice transgenic lines showed marked increase in PCS activity and enhanced synthesis of PCs in comparison to non-transgenic plant. Transgenic lines showed enhanced accumulation of As in root and shoot. This enhanced metal accumulation potential of transgenic lines was positively correlated to the content of PCs, which also increased several-fold higher in transgenic lines. However, all the transgenic lines accumulated significantly lower As in grain and husk in comparison to non-transgenic plant. The higher level of PCs in transgenic plants relative to non-transgenic presumably allowed sequestering and detoxification of higher amounts of As in roots and shoots, thereby restricting its accumulation in grain.
Assuntos
Aminoaciltransferases/biossíntese , Arsênio/metabolismo , Carcinógenos/metabolismo , Oryza/genética , Proteínas de Plantas/biossíntese , Sementes/genética , Aminoaciltransferases/genética , Inocuidade dos Alimentos , Expressão Gênica , Glutationa/metabolismo , Oryza/enzimologia , Oryza/crescimento & desenvolvimento , Proteínas de Plantas/genética , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/enzimologia , Plantas Geneticamente Modificadas/genética , Plântula/enzimologia , Plântula/genética , Plântula/crescimento & desenvolvimento , Sementes/enzimologia , Sementes/crescimento & desenvolvimentoRESUMO
INTRODUCTION: Monocytic cells play a central role in the aetiology of rheumatoid arthritis, and manipulation of the activation of these cells is an approach currently under investigation to discover new therapies for this and associated diseases. CD148 is a transmembrane tyrosine phosphatase that is highly expressed in monocytes and macrophages and, since this family of molecules plays an important role in the regulation of cell activity, CD148 is a potential target for the manipulation of macrophage activation. For any molecule to be considered a therapeutic target, it is important for it to be increased in activity or expression during disease. METHODS: We have investigated the expression of CD148 in two murine models of arthritis and in joints from rheumatoid arthritis (RA) patients using real-time PCR, immunohistochemistry, and studied the effects of proinflammatory stimuli on CD148 activity using biochemical assays. RESULTS: We report that CD148 mRNA is upregulated in diseased joints of mice with collagen-induced arthritis. Furthermore, we report that in mice CD148 protein is highly expressed in infiltrating monocytes of diseased joints, with a small fraction of T cells also expressing CD148. In human arthritic joints both T cells and monocytes expressed high levels of CD148, however, we show differential expression of CD148 in T cells and monocytes from normal human peripheral blood compared to peripheral blood from RA and both normal and RA synovial fluid. Finally, we show that synovial fluid from rheumatoid arthritis patients suppresses CD148 phosphatase activity. CONCLUSIONS: CD148 is upregulated in macrophages and T cells in human RA samples, and its activity is enhanced by treatment with tumour necrosis factor alpha (TNFα), and reduced by synovial fluid or oxidising conditions. A greater understanding of the role of CD148 in chronic inflammation may lead to alternative therapeutic approaches to these diseases.
Assuntos
Artrite Experimental/genética , Artrite Reumatoide/genética , Perfilação da Expressão Gênica , Leucócitos Mononucleares/metabolismo , Animais , Artrite Experimental/metabolismo , Artrite Experimental/patologia , Artrite Reumatoide/metabolismo , Artrite Reumatoide/patologia , Humanos , Peróxido de Hidrogênio/farmacologia , Imuno-Histoquímica , Articulações/metabolismo , Articulações/patologia , Leucócitos Mononucleares/patologia , Macrófagos/metabolismo , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Microscopia Confocal , Monócitos/metabolismo , Monócitos/patologia , Oxidantes/farmacologia , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Líquido Sinovial/metabolismo , Linfócitos T/efeitos dos fármacos , Linfócitos T/metabolismo , Linfócitos T/patologia , Fator de Necrose Tumoral alfa/farmacologia , Regulação para CimaRESUMO
PTPRJ/CD148 is a tyrosine phosphatase that has tumour suppressor-like activity. Quantitative PCR of various cells and tissues revealed that it is preferentially expressed in macrophage-enriched tissues. Within lymphoid tissues immunohistochemistry revealed that PTPRJ/CD148 co-localised with F4/80, indicating that macrophages most strongly express the protein. Macrophages express the highest basal level of ptprj, and this is elevated further by treatment with LPS and other Toll-like receptor ligands. In contrast, CSF-1 treatment reduced basal and stimulated Ptprj expression in human and mouse cells, and interferon also repressed Ptprj expression. We identified a 1006 nucleotide long noncoding RNA species, Ptprj-as1 that is transcribed antisense to Ptprj. Ptprj-as1 was highly expressed in macrophage-enriched tissue and was transiently induced by Toll-like receptor ligands with a similar time course to Ptprj. Finally, putative transcription factor binding sites in the promoter region of Ptprj were identified.
Assuntos
Inflamação/genética , Macrófagos/metabolismo , RNA não Traduzido/genética , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismo , Animais , Sequência de Bases , Linhagem Celular , Células HEK293 , Humanos , Inflamação/metabolismo , Fator Estimulador de Colônias de Macrófagos/genética , Fator Estimulador de Colônias de Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Células NIH 3T3 , Fagócitos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA não Traduzido/metabolismo , Receptores Toll-Like/genética , Receptores Toll-Like/metabolismoRESUMO
Carcinogenic arsenic (As) concentrations are found in rice due to irrigation with contaminated groundwater in South-East Asia. The present study evaluates comparative antioxidant property and specific amino acid accumulation in contrasting rice genotypes corresponding to differential As accumulation during arsenate (As(V)) and arsenite (As(III)) exposures. The study was conducted on two contrasting As accumulating rice genotypes selected from 303 genotype accessions, in hydroponic conditions. Maximum As accumulation was up to 1181 µg g(-1) dw in the roots of high As accumulating genotype (HARG), and 89 µg g(-1) dw in low As accumulating genotype (LARG) under As(III) exposures. The inorganic As was correlated more significantly upon exposures to As(III) than As(V). In the presence of As(V) various antioxidant enzymes guiacol peroxidase (GPX), ascorbate peroxidase (APX) and superoxide dismutase (SOD) were highly stimulated in HARG. The stress responsive amino acids proline, cysteine, glycine, glutamic acid and methionine showed higher accumulation in HARG than LARG. A clear correlation was found between stress responsive amino acids, As accumulation and antioxidative response. The comparisons between the contrasting genotypes helped to determine the significance of antioxidants and specific amino acid response to As stress.
Assuntos
Aminoácidos/química , Antioxidantes/química , Arseniatos/química , Arsenitos/química , Oryza/metabolismo , Arsênio/análise , Arsênio/química , Ascorbato Peroxidases/metabolismo , Genótipo , Água Subterrânea , Hidroponia , Peroxidação de Lipídeos , Malondialdeído/química , Metais/química , Oryza/genética , Estresse Oxidativo , Peroxidase/metabolismo , Raízes de Plantas/metabolismo , Espécies Reativas de Oxigênio/química , Poluentes do Solo/química , Superóxido Dismutase/metabolismoRESUMO
Thiol metabolism is the primary detoxification strategy by which rice plants tolerate arsenic (As) stress. In light of this, it is important to understand the importance of harmonised thiol metabolism with As accumulation and tolerance in rice plant. For this aim, tolerant (T) and sensitive (S) genotypes were screened from 303 rice (Oryza sativa) genotypes on exposure to 10 and 25 µM arsenite (As(III)) in hydroponic culture. On further As accumulation estimation, contrasting (13-fold difference) T (IC-340072) and S (IC-115730) genotypes were selected. This difference was further evaluated using biochemical and molecular approaches to understand involvement of thiolic metabolism vis-a-vis As accumulation in these two genotypes. Various phytochelatin (PC) species (PC(2), PC(3) and PC(4)) were detected in both the genotypes with a dominance of PC(3). However, PC concentrations were greater in the S genotype, and it was noticed that the total PC (PC(2) + PC(3 )+ PC(4))-to-As(III) molar ratio (PC-SH:As(III)) was greater in T (2.35 and 1.36 in shoots and roots, respectively) than in the S genotype (0.90 and 0.15 in shoots and roots, respectively). Expression analysis of several metal(loid) stress-related genes showed significant upregulation of glutaredoxin, sulphate transporter, and ascorbate peroxidase in the S genotype. Furthermore, enzyme activity of phytochelatin synthase and cysteine synthase was greater on As accumulation in the S compared with the T genotype. It was concluded that the T genotype synthesizes adequate thiols to detoxify metalloid load, whereas the S genotype synthesizes greater but inadequate levels of thiols to tolerate an exceedingly greater load of metalloids, as evidenced by thiol-to-metalloid molar ratios, and therefore shows a phytotoxicity response.
Assuntos
Adaptação Fisiológica/fisiologia , Arsenitos/toxicidade , Oryza/fisiologia , Poluentes do Solo/toxicidade , Compostos de Sulfidrila/metabolismo , Aminoaciltransferases/metabolismo , Regulação da Expressão Gênica de Plantas , Fitoquelatinas/metabolismoRESUMO
The protein tyrosine phosphatase receptor J, PTPRJ, is a tumor suppressor gene that has been implicated in a range of cancers, including breast cancer, yet little is known about its role in normal breast physiology or in mammary gland tumorigenesis. In this paper we show that PTPRJ mRNA is expressed in normal breast tissue and reduced in corresponding tumors. Meta-analysis revealed that the gene encoding PTPRJ is frequently lost in breast tumors and that low expression of the transcript associated with poorer overall survival at 20 years. Immunohistochemistry of PTPRJ protein in normal human breast tissue revealed a distinctive apical localisation in the luminal cells of alveoli and ducts. Qualitative analysis of a cohort of invasive ductal carcinomas revealed retention of normal apical PTPRJ localization where tubule formation was maintained but that tumors mostly exhibited diffuse cytoplasmic staining, indicating that dysregulation of localisation associated with loss of tissue architecture in tumorigenesis. The murine ortholog, Ptprj, exhibited a similar localisation in normal mammary gland, and was differentially regulated throughout lactational development, and in an in vitro model of mammary epithelial differentiation. Furthermore, ectopic expression of human PTPRJ in HC11 murine mammary epithelial cells inhibited dome formation. These data indicate that PTPRJ may regulate differentiation of normal mammary epithelia and that dysregulation of protein localisation may be associated with tumorigenesis.
Assuntos
Neoplasias da Mama/enzimologia , Neoplasias da Mama/patologia , Células Epiteliais/enzimologia , Glândulas Mamárias Animais/enzimologia , Glândulas Mamárias Humanas/enzimologia , Animais , Neoplasias da Mama/genética , Diferenciação Celular/genética , Linhagem Celular Tumoral , Regulação para Baixo/genética , Células Epiteliais/patologia , Epitélio/enzimologia , Epitélio/patologia , Feminino , Dosagem de Genes/genética , Regulação Neoplásica da Expressão Gênica , Loci Gênicos/genética , Humanos , Íntrons/genética , Glândulas Mamárias Animais/crescimento & desenvolvimento , Glândulas Mamárias Animais/patologia , Glândulas Mamárias Humanas/patologia , Neoplasias Mamárias Animais/enzimologia , Neoplasias Mamárias Animais/genética , Neoplasias Mamárias Animais/patologia , Metanálise como Assunto , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , RNA Antissenso/genética , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismoRESUMO
Recent breakthroughs in rice arsenic (As) research demonstrate that As accumulation significantly affects trace nutrients in rice grain. In the present study we analyzed the amino acid (AA) profile of sixteen rice genotypes differing in grain As accumulation, grown at three sites with different soil As concentrations, in ascending order, ChinsurahAssuntos
Aminoácidos/química
, Arsênio/química
, Oryza/química
, Aminoácidos Essenciais/química
, Dieta
, Genótipo
, Índia
, Oryza/genética
, Sementes/química
, Poluentes Químicos da Água/química
RESUMO
Arsenic (As) is a widespread environmental and food chain contaminant and class I, non-threshold carcinogen. Plants accumulate As due to ionic mimicry that is of importance as a measure of phytoremediation but of concern due to the use of plants in alternative medicine. The present study investigated As accumulation in native plants including some medicinal plants, from three districts [Chinsurah (Hoogly), Porbosthali (Bardhman), and Birnagar (Nadia)] of West Bengal, India, having a history of As pollution. A site-specific response was observed for Specific Arsenic Uptake (SAU; mg kg(-1) dw) in total number of 13 (8 aquatic and 5 terrestrial) collected plants. SAU was higher in aquatic plants (5-60 mg kg(-1) dw) than in terrestrial species (4-19 mg kg(-1) dw). The level of As was lower in medicinal plants (MPs) than in non-medicinal plants, however it was still beyond the WHO permissible limit (1 mg kg(-1) dw). The concentration of other elements (Cu, Zn, Se, and Pb) was found to be within prescribed limits in medicinal plants (MP). Among the aquatic plants, Marsilea showed the highest SAU (avg. 45 mg kg(-1) dw), however, transfer factor (TF) of As was the maximum in Centella asiatica (MP, avg. 1). Among the terrestrial plants, the maximum SAU and TF were demonstrated by Alternanthera ficoidea (avg. 15) and Phyllanthus amarus (MP, avg. 1.27), respectively. In conclusion, the direct use of MP or their by products for humans should not be practiced without proper regulation. In other way, one fern species (Marsilea) and some aquatic plants (Eichhornia crassipes and Cyperus difformis) might be suitable candidates for As phytoremediation of paddy fields.
Assuntos
Arsênio/análise , Plantas/metabolismo , Poluentes do Solo/análise , Arsênio/metabolismo , Biodegradação Ambiental , Monitoramento Ambiental , Índia , Plantas Medicinais/efeitos adversos , Plantas Medicinais/química , Plantas Medicinais/metabolismo , Poluentes do Solo/metabolismoRESUMO
BACKGROUND: Hedgehog (Hh) signaling is crucial for the generation and maintenance of both embryonic and adult stem cells, thereby regulating development and tissue homeostasis. In the developing neocortex, Sonic Hedgehog (Shh) regulates neural progenitor cell proliferation. During neurogenesis, radial glial cells of the ventricular zone (VZ) are the predominant neocortical progenitors that generate neurons through both symmetric and asymmetric divisions. Despite its importance, relatively little is known of the molecular pathways that control the switch from symmetric proliferative to differentiative/neurogenic divisions in neural progenitors. PRINCIPAL FINDINGS: Here, we report that conditional inactivation of Patched1, a negative regulator of the Shh pathway, in Nestin positive neural progenitors of the neocortex leads to lamination defects due to improper corticogenesis and an increase in the number of symmetric proliferative divisions of the radial glial cells. Hedgehog-activated VZ progenitor cells demonstrated a concomitant upregulation of Hes1 and Blbp, downstream targets of Notch signaling. The Notch signaling pathway plays a pivotal role in the maintenance of stem/progenitor cells and the regulation of glial versus neuronal identity. To study the effect of Notch signaling on Hh-activated neural progenitors, we inactivated both Patched1 and Rbpj, a transcriptional mediator of Notch signaling, in Nestin positive cells of the neocortex. CONCLUSIONS: Our data indicate that by mid neurogenesis (embryonic day 14.5), attenuation of Notch signaling reverses the effect of Patched1 deletion on neurogenesis by restoring the balance between symmetric proliferative and neurogenic divisions. Hence, our results demonstrate that correct corticogenesis is an outcome of the interplay between the Hh and Notch signaling pathways.
Assuntos
Divisão Celular/genética , Proteínas Hedgehog/fisiologia , Neocórtex/embriologia , Células-Tronco Neurais/fisiologia , Neurogênese/genética , Receptores Notch/fisiologia , Animais , Padronização Corporal/genética , Padronização Corporal/fisiologia , Divisão Celular/fisiologia , Células Cultivadas , Embrião de Mamíferos , Feminino , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Proteínas de Filamentos Intermediários/metabolismo , Camundongos , Camundongos Transgênicos , Neocórtex/citologia , Neocórtex/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Nestina , Células-Tronco Neurais/metabolismo , Neurogênese/fisiologia , Receptores Patched , Receptor Patched-1 , Gravidez , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/fisiologia , Receptores Notch/genética , Receptores Notch/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/fisiologiaRESUMO
World wide arsenic (As) contamination of rice has raised much concern as it is the staple crop for millions. Four most commonly cultivated rice cultivars, Triguna, IR-36, PNR-519 and IET-4786, of the West Bengal region were taken for a hydroponic study to examine the effect of arsenate (As(V)) and arsenite (As(III)) on growth response, expression of genes and antioxidants vis-à-vis As accumulation. The rice genotypes responded differentially under As(V) and As(III) stress in terms of gene expression and antioxidant defences. Some of the transporters were up-regulated in all rice cultivars at lower doses of As species, except IET-4786. Phytochelatin synthase, GST and γ-ECS showed considerable variation in their expression pattern in all genotypes, however in IET-4786 they were generally down-regulated in higher As(III) stress. Similarly, most of antioxidants such as superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) increased significantly in Triguna, IR-36 and PNR-519 and decreased in IET-4786. Our study suggests that Triguna, IR-36 and PNR-519 are tolerant rice cultivars accumulating higher arsenic; however IET-4786 is susceptible to As-stress and accumulates less arsenic than other cultivars.
Assuntos
Adaptação Fisiológica , Arsênio/toxicidade , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Oryza/efeitos dos fármacos , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Arseniatos/metabolismo , Arseniatos/toxicidade , Arsênio/metabolismo , Arsenitos/metabolismo , Arsenitos/toxicidade , Ascorbato Peroxidases , Catalase/metabolismo , Expressão Gênica/efeitos dos fármacos , Genes de Plantas , Inativação Metabólica/genética , Peroxidação de Lipídeos/efeitos dos fármacos , Oryza/genética , Oryza/fisiologia , Estresse Oxidativo , Oxirredutases/metabolismo , Peroxidases/metabolismo , Transdução de Sinais/efeitos dos fármacos , Enxofre/metabolismo , Superóxido Dismutase/metabolismoRESUMO
Aminoacyl-tRNA (aa-tRNA), in a ternary complex with elongation factor-Tu and GTP, enters the aminoacyl (A) site of the ribosome via a multi-step, mRNA codon-dependent mechanism. This process gives rise to the preferential selection of cognate aa-tRNAs for each mRNA codon and, consequently, the fidelity of gene expression. The ribosome actively facilitates this process by recognizing structural features of the correct substrate, initiated in its decoding site, to accelerate the rates of elongation factor-Tu-catalyzed GTP hydrolysis and ribosome-catalyzed peptide bond formation. Here, the order and timing of conformational events underpinning the aa-tRNA selection process were investigated from multiple structural perspectives using single-molecule fluorescence resonance energy transfer. The time resolution of these measurements was extended to 2.5 and 10 ms, a 10- to 50-fold improvement over previous studies. The data obtained reveal that aa-tRNA undergoes fast conformational sampling within the A site, both before and after GTP hydrolysis. This suggests that the alignment of aa-tRNA with respect to structural elements required for irreversible GTP hydrolysis and peptide bond formation plays a key role in the fidelity mechanism. These observations provide direct evidence that the selection process is governed by motions of aa-tRNA within the A site, adding new insights into the physical framework that helps explain how the rates of GTP hydrolysis and peptide bond formation are controlled by the mRNA codon and other fidelity determinants within the system.
Assuntos
Escherichia coli/metabolismo , RNA Bacteriano/química , RNA Bacteriano/metabolismo , Aminoacil-RNA de Transferência/química , Aminoacil-RNA de Transferência/metabolismo , Ribossomos/metabolismo , Códon/genética , Códon/metabolismo , Escherichia coli/genética , Transferência Ressonante de Energia de Fluorescência , Corantes Fluorescentes , Guanosina Trifosfato/química , Guanosina Trifosfato/metabolismo , Hidrólise , Cinética , Substâncias Macromoleculares , Modelos Biológicos , Modelos Moleculares , Conformação de Ácido Nucleico , Fator Tu de Elongação de Peptídeos/química , Fator Tu de Elongação de Peptídeos/metabolismo , RNA Bacteriano/genética , RNA de Transferência de Metionina/química , RNA de Transferência de Metionina/metabolismo , RNA de Transferência de Fenilalanina/química , RNA de Transferência de Fenilalanina/metabolismoRESUMO
The exposure of paddy fields to arsenic (As) through groundwater irrigation is a serious concern that may not only lead to As accumulation to unacceptable levels but also interfere with mineral nutrients in rice grains. In the present field study, profiling of the mineral nutrients (iron (Fe), phosphorous, zinc, and selenium (Se)) was done in various rice genotypes with respect to As accumulation. A significant genotypic variation was observed in elemental retention on root Fe plaque and their accumulation in various plant parts including grains, specific As uptake (29-167 mg kg(-1) dw), as well as As transfer factor (4-45%). Grains retained the least level of As (0.7-3%) with inorganic As species being the dominant forms, while organic As species, viz., dimethylarsinic acid and monomethylarsonic acid, were non-detectable. In all tested varieties, the level of Se was low (0.05-0.12 mg kg(-1) dw), whereas that of As was high (0.4-1.68 mg kg(-1) dw), considering their safe/recommended daily intake limits, which may not warrant their human consumption. Hence, their utilization may increase the risk of arsenicosis, when grown in As-contaminated areas.
Assuntos
Arsênio/farmacologia , Contaminação de Alimentos , Alimentos , Minerais , Oryza , Poluentes do Solo/farmacologia , Agricultura , Humanos , Índia , Oryza/anatomia & histologia , Oryza/efeitos dos fármacos , Oryza/metabolismo , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Solo/químicaRESUMO
In macrophages, tyrosine phosphorylation regulates many signalling pathways leading to growth, differentiation, activation, phagocytosis and adhesion. Protein tyrosine phosphatases (PTPs) represent a biochemical counterbalance to the activity of protein tyrosine kinases, thus regulating the dynamic phosphorylation state of a cell. CD148 is a receptor PTP that is highly expressed in macrophages and is further regulated by pro-inflammatory stimuli. CD148 is normally localised to the plasma membrane of macrophages. Following stimulation with CSF-1 or LPS, there was a re-distribution and concentration of CD148 in areas of membrane ruffling. Treatment of macrophages with anti-CD148 monoclonal antibody inhibited CSF-1-induced macrophage spreading, cytoskeletal re-arrangements and chemotaxis, without affecting cell survival. There were no detectable effects on the CSF-1 receptor-akt signalling pathway. These results are consistent with the hypothesis that CD148 is a regulator of macrophage activity.
Assuntos
Citoesqueleto/enzimologia , Macrófagos/citologia , Macrófagos/enzimologia , Actinas/metabolismo , Animais , Anticorpos Monoclonais/farmacologia , Proliferação de Células/efeitos dos fármacos , Extensões da Superfície Celular/efeitos dos fármacos , Extensões da Superfície Celular/enzimologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Quimiotaxia/efeitos dos fármacos , Reagentes de Ligações Cruzadas/farmacologia , Citoesqueleto/efeitos dos fármacos , Endocitose/efeitos dos fármacos , Humanos , Lipopolissacarídeos/farmacologia , Fator Estimulador de Colônias de Macrófagos/farmacologia , Macrófagos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacos , Transporte Proteico/efeitos dos fármacos , Receptor de Fator Estimulador de Colônias de Macrófagos/metabolismo , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/metabolismoRESUMO
Organic fluorophores common to fluorescence-based investigations suffer from unwanted photophysical properties, including blinking and photobleaching, which limit their overall experimental performance. Methods to control such processes are particularly important for single-molecule fluorescence and fluorescence resonance energy transfer imaging where uninterrupted, stable fluorescence is paramount. Fluorescence and FRET-based assays have been carried out on dye-labeled DNA and RNA-based systems to quantify the effect of including small-molecule solution additives on the fluorescence and FRET behaviors of both cyanine and Alexa fluorophores. A detailed dwell time analysis of the fluorescence and FRET trajectories of more than 200,000 individual molecules showed that two compounds identified previously as triplet state quenchers, cyclooctatetraene, and Trolox, as well as 4-nitrobenzyl alcohol, act to favorably attenuate blinking, photobleaching, and influence the rate of photoresurrection in a concentration-dependent and context-dependent manner. In both biochemical systems examined, a unique cocktail of compounds was shown to be optimal for imaging performance. By simultaneously providing the most rapid and direct access to multiple photophysical kinetic parameters, smFRET imaging provides a powerful avenue for future investigations aimed at discovering new compounds, and effective combinations thereof. These efforts may ultimately facilitate tuning organic dye molecule performance according to each specific experimental demand.