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1.
PLoS One ; 18(7): e0288133, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37494333

RESUMO

The involvement of microorganisms in low-density polyethylene (LDPE) degradation is widely studied across the globe. Even though soil, landfills, and garbage dumps are reported to be promising niches for such organisms, recently the involvement of wood decay fungi in polyethylene degradation is highlighted. In light of this, 50 fungal samples isolated from decaying hardwoods were assessed for their wood degradation ability and for their depolymerization enzymatic activities. For the LDPE deterioration assay, 22 fungal isolates having wood decay ability and de-polymerization enzymatic activities were selected. Fungal cultures with LDPE sheets (2 cm x 10 cm x 37.5 µm) were incubated in the presence and in the absence of wood as the carbon source (C) for 45 days. Degradation was measured by weight loss, changes in tensile properties, reduction in contact angle, changes of functional groups in Fourier-transform infrared spectroscopy, Scanning electron microscopic imaging, and CO2 evolution by strum test. Among the isolates incubated in the absence of wood, Phlebiopsis flavidoalba out-performed the other fungal species showing the highest percentage of weight reduction (23.68 ± 0.34%), and the lowest contact angle (64.28° ± 5.01). Biodegradation of LDPE by P. flavidoalba was further supported by 46.79 ± 0.67% of the mass loss, and 3.07 ± 0.13% of CO2 emission (mg/L) in the strum test. The most striking feature of the experiment was that all the isolates showed elevated degradation of LDPE in the absence of wood than that in the presence of wood. It is clear that in the absence of a preferred C source, wood decay fungi thrive to utilize any available C source (LDPE in this case) showing the metabolic adaptability of fungi to survive under stressful conditions. A potential mechanism for LDPE degradation is also proposed.


Assuntos
Polietileno , Madeira , Polietileno/química , Madeira/metabolismo , Meios de Cultura/metabolismo , Dióxido de Carbono/metabolismo , Biodegradação Ambiental , Fungos/metabolismo
2.
Pathogens ; 12(2)2023 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-36839566

RESUMO

Phytoplasmas are associated with many plant diseases. In palms, lethal bronzing disease, Texas Phoenix palm decline, and coconut lethal yellowing decline are some of them. In Sri Lanka, coconut leaf wilt decline has been reported in the Weligama area of the Southern province, and the disease is called Weligama coconut leaf wilt disease (WCLWD). Unlike other phytoplasma diseases of palms, WCLWD shows slow disease progress. Pathogen detection entirely relies on nested polymerase chain reaction (PCR). However, inconsistencies in pathogen detection have been experienced, i.e., symptomatic plants often produce negative results. The objectives of this study were to reconsider the choice of primers and to determine the best sampling tissue types for consistent detection of the pathogen. Among the six universal primer combinations tested, P1/Tint nested with fU5/rU3 produced consistent results. BLASTn searches of the sequences showed 99-100% similarity to sugarcane white leaf disease (SWL) or grassy shoot (SGS) disease-causing phytoplasma. The optimized nested PCR protocol was successful, with the minimum success rating of 88% and 100% specificity. Midribs of milky white bud leaf samples were the best tissue type for rapid detection. Systemic movement of the pathogen and a tentative latent period were also reported. The findings are helpful in the early detection of the disease.

3.
Environ Res ; 215(Pt 1): 114242, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36067842

RESUMO

Over the past few years, synthetic dye-contaminated wastewater has attracted considerable global attention due to the low biodegradability and the ability of organic dyes to persist and remain toxic, causing numerous health and environmental concerns. As a result of the recalcitrant nature of those complex organic dyes, the remediation of wastewater using conventional wastewater treatment techniques is becoming increasingly challenging. In recent years, advanced oxidation processes (AOPs) have emerged as a potential alternative to treat organic dyestuffs discharged from industries. The most widely employed AOPs include photocatalysis, ozonation, Fenton oxidation, electrochemical oxidation, catalytic heterogeneous oxidation, and ultrasound irradiation. These processes involve the generation of highly reactive radicals to oxidize organic dyes into innocuous minerals. However, many conventional AOPs suffer from several setbacks, including the high cost, high consumption of reagents and substrates, self-agglomeration of catalysts, limited reusability, and the requirement of light, ultrasound, or electricity. Therefore, there has been significant interest in improving the performance of conventional AOPs using biopolymers and heterogeneous catalysts such as metal oxide nanoparticles (MONPs). Biopolymers have been widely considered in developing green, sustainable, eco-friendly, and low-cost AOP-based dye removal technologies. They inherit intriguing properties like biodegradability, renewability, nontoxicity, relative abundance, and sorption. In addition, the immobilization of catalysts on biopolymer supports has been proven to possess excellent catalytic activity and turnover numbers. The current review provides comprehensive coverage of different AOPs and how efficiently biopolymers, including cellulose, chitin, chitosan, alginate, gelatin, guar gum, keratin, silk fibroin, zein, albumin, lignin, and starch, have been integrated with heterogeneous AOPs in dye removal applications. This review also discusses the general degradation mechanisms of AOPs, applications of biopolymers in AOPs and the roles of biopolymers in AOPs-based dye removal processes. Furthermore, key challenges and future perspectives of biopolymer-based AOPs have also been highlighted.


Assuntos
Quitosana , Fibroínas , Ozônio , Poluentes Químicos da Água , Purificação da Água , Zeína , Albuminas , Alginatos , Corantes , Gelatina , Queratinas , Lignina , Oxirredução , Óxidos , Amido , Águas Residuárias , Poluentes Químicos da Água/química
4.
Sci Rep ; 12(1): 3911, 2022 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-35273240

RESUMO

Aromatic rice (Oryza sativa) fetches a premium price due to the pleasant aroma. The major aroma compound 2-acetyl-1-pyrroline (2AP) has been found to be enhanced under stress. This condition can be considered to study the genes, precursors, enzymes, and metabolites involved in elevated levels of 2AP biosynthesis. In the present study, 100 mM salt treatment was given to two aromatic rice cultivars Ambemohar-157 (A-157) and Basmati-370 (B-370) at the vegetative stage (VS3). After salt treatment, in the leaves, 2AP contents were elevated by 2.2 and 1.8 fold in A-157 and B-370, respectively. Under these elevated 2AP conditions, the precursor amino acids (glutamate, putrescine, ornithine, and proline), their related genes, enzymes, and metabolites (methylglyoxal and γ-aminobutyric acid (GABA) related to 2AP biosynthesis were analyzed. In addition, agronomic characters were also studied. It was observed that the proline content was enhanced in both the cultivars by 29% (A-157) and 40% (B-370) as compared to control. The Δ1-pyrroline-5-carboxylate synthetase (P5CS) enzyme activity was increased in salt-treated plants leaf tissue by 31% (A-157) and 40% (B-370) compared to control. The P5CS gene expression was enhanced by A-157 (1.8 fold) and B-370 (2.2 fold) compared to control, putrescine content in A-157 and B-370 decreased by 2.5 and 2.7 fold respectively as compared to control. The ornithine decarboxylase (ODC) activity was enhanced in A-157 (12%) and B-370 (35%) over control. Further, ODC gene expression was enhanced in both the cultivars A-157 (1.5 fold) and B-370 (1.3 fold). The diamino oxidase (DAO) enzyme activity was increased by 28% (A-157) and 35% (B-370) respectively over control. The GABA content marginally increased over control in both the cultivars namely, A-157 (1.9%) and B-370 (9.5%). The methylglyoxal levels were enhanced by 1.4 fold in A-157 and 1.6 fold in B-370. Interestingly, the enhancement in 2AP in the vegetative stage also helped to accumulate it in mature grains (twofold in A-157 and 1.5 fold in B-370) without test weight penalty. The study indicated that the ornithine and proline together along with methylglyoxal contribute towards the enhancement of 2AP under salt stress.


Assuntos
Oryza , Aminoácidos/metabolismo , Ornitina/metabolismo , Oryza/metabolismo , Prolina/metabolismo , Putrescina/metabolismo , Pirróis , Aldeído Pirúvico/metabolismo , Estresse Salino , Ácido gama-Aminobutírico/metabolismo
5.
Pathogens ; 10(2)2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33525615

RESUMO

Anaerobic soil disinfection (ASD) has been identified as an alternative soil-borne pathogen control strategy to chemical fumigation. ASD involves the application of an easily liable carbon source followed by irrigation to field capacity and maintenance of an anaerobic condition for a certain period. A literature search undertaken on ASD found that more than 50 comprehensive research projects have been conducted since its first discovery in 2000. Most of these studies were conducted in the USA and in the Netherlands. Though the exact mechanism of ASD in pathogen control is unknown, promising results have been reported against a wide range of pathogens such as fungi, nematodes, protists, and oomycetes. However, it is interesting to note that, except for a few studies, ASD research in the developing world and in the tropical countries has lagged behind. Nevertheless, with soil quality depletion, reduction in arable lands, and exponential population growth, a drastic change to the current agricultural practices should be adapted since yield gain has reached a plateau for major staple crops. Under such circumstances, we identified the gaps and the potentials of ASD in tropical agricultural systems and proposed promising biodegradable materials.

6.
Biol Trace Elem Res ; 186(1): 122-134, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29552710

RESUMO

Recently, several attempts have been made to use the phytopharmaceuticals from plant extracts as reducing, capping and stabilizing agents for the biomimetic synthesis of various metal nanoparticles conjugated to the phytopharmaceuticals. These biogenic metal nanoparticles are non-toxic and can be used as contrast agents, drug delivery vehicles and photothermal agents for cancer therapy. Herein, we report the synthesis of both silver and gold nanoparticles using the pollen extract of Phoenix dactylifera (Date Palm), characterization using UV-visible spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy, quantitation of phytochemicals capping the nanoparticles using Folin - Ciocalteu's method, cytotoxicity studies on MCF-7 breast cancer cells, cancer cell death analysis using fluorescent microscopy, and modulation of expression of the pro-apoptotic p53 and anti-apoptotic Bcl-2 proteins. The biosynthesis resulted in stable and poly-dispersed silver nanoparticles and gold nanoparticles, exhibiting strong and broad surface plasmon absorption peaks. The elemental analysis confirmed the presence of gold and silver of high purity and also the organic moieties from the plant extract acting as capping and stabilizing agents. The biogenic nanoparticles also exhibited dose-dependent cytotoxicity on MCF-7 cells and showed signs of apoptotic cell death. Immunoassays revealed the upregulation of the pro-apoptotic protein p53 and down-regulation of the anti-apoptotic protein Bcl-2 after the nanoparticle treatment.


Assuntos
Adenocarcinoma/tratamento farmacológico , Antineoplásicos Fitogênicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Extratos Vegetais/farmacologia , Pólen/química , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteína Supressora de Tumor p53/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Apoptose/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Ouro/química , Ouro/farmacologia , Humanos , Células MCF-7 , Nanopartículas Metálicas/química , Phoeniceae/química , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Proteínas Proto-Oncogênicas c-bcl-2/análise , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Prata/química , Prata/farmacologia , Relação Estrutura-Atividade , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/análise , Proteína Supressora de Tumor p53/metabolismo
7.
Food Chem ; 191: 2-6, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26258694

RESUMO

39 aromatic indica rice (Oryza sativa L.) cultivars were characterized for Iron, Zinc, Calcium, Magnesium, Copper and ß-carotene contents. The ß-carotene contents were ranging from 1.23 to 9.9µg/g in brown and 0.08 to 1.99µg/g in milled rice. Among the mineral contents, Magnesium was found ranging from 855µg/g (Gham) to maximum of 1636µg/g (Badshahbhog) followed by Iron in 32µg/g (Jirga) to 218µg/g (Kalsal), Copper content from 2µg/g (Girga) to 1004µg/g (Gham), Zinc content from 25 (Gham) to 165µg/g (Ambemohar-157) and Calcium ranged from 14µg/g (Ambemohar pandhara) to 67µg/g (Kate chinoor). The study showed that the germplasm assessed is a good source of micronutrients and can be further exploited in breeding programme.


Assuntos
Oryza/química , beta Caroteno/análise , Cálcio/análise , Cobre/análise , Ferro/análise , Magnésio/análise , Zinco/análise
8.
J Photochem Photobiol B ; 149: 116-28, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26057021

RESUMO

The current research focuses on the application of folate conjugated and doxorubicin loaded polymeric gold nanoparticles (GNPs) for the targeted treatment of folate receptor overexpressing breast cancers, augmented by adjunctive laser photothermal therapy. Herein, GNPs surface modified with folate, drug doxorubicin and polyethylene glycol were engineered and were used as vehicles for folate receptor targeted delivery of doxorubicin into cancer cells. Subsequently, the GNPs were photo-excited using laser light for mediating hyperthermia in the cancer cells. In vitro studies were performed to validate the efficacy of the combined modality of folate conjugated and doxorubicin loaded polymeric GNP mediated chemotherapy followed by photothermal therapy in comparison to treatment with free drug; and the combination modality showed better therapeutic efficacy than that of plain doxorubicin treatment in MDA-MB-231 breast cancer cells that express increased levels of surface folate receptors when compared to MCF-7 breast cancer cells that express low levels of folate receptor. The mechanism of cell death was investigated using fluorescent microscopy. Immunoassays showed the up-regulation of the pro-apoptotic protein p53 and down-regulation of the anti-apoptotic protein Bcl-2. Collectively, these results suggest that the folate tagged doxorubicin loaded GNPs are an attractive platform for targeted delivery of doxorubicin and are agents suitable for photothermal cancer therapy.


Assuntos
Neoplasias da Mama/patologia , Doxorrubicina/farmacologia , Transportadores de Ácido Fólico/metabolismo , Ouro/química , Terapia a Laser , Terapia de Alvo Molecular , Polímeros/química , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Neoplasias da Mama/tratamento farmacológico , Linhagem Celular Tumoral , Doxorrubicina/química , Doxorrubicina/uso terapêutico , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Ácido Fólico/química , Humanos , Cinética , Nanopartículas Metálicas/química , Necrose , Fototerapia , Polietilenoglicóis/química , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ácidos Sulfônicos/química , Propriedades de Superfície , Proteína Supressora de Tumor p53/metabolismo
9.
Artigo em Inglês | MEDLINE | ID: mdl-25240832

RESUMO

In the present work, pure and metal substituted L-Prolinium trichloroacetate (LPTCA) single crystals were grown by slow evaporation method. The grown crystals were subjected to single crystal X-ray diffraction (XRD), powder X-ray diffraction, FTIR, UV-Visible-NIR, hardness, photoluminescence and dielectric studies. The dopant concentration in the crystals was measured by inductively coupled plasma (ICP) analysis. Single crystal X-ray diffraction studies of the pure and metal substituted LPTCA revealed that the grown crystals belong to the trigonal system. Ni(2+) and Co(2+) doping slightly altered the lattice parameters of LPTCA without affecting the basic structure of the crystal. FTIR spectral analysis confirms the presence of various functional groups in the grown crystals. The mechanical behavior of pure and doped crystals was analyzed by Vickers's microhardness test. The optical transmittance, dielectric and photoluminescence properties of the pure and doped crystals were analyzed.


Assuntos
Cobalto/química , Níquel/química , Prolina/química , Ácido Tricloroacético/química , Cristalização , Cristalografia por Raios X , Dureza , Luminescência , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier
10.
Oman J Ophthalmol ; 8(3): 185-7, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26903728

RESUMO

Choroidal osteoma is an uncommon benign osseous intraocular tumor typically seen unilaterally in young women. Visual loss can occur due to choroidal neovascularization (CNV) complicating osteoma. We report a rare case of bilateral choroidal osteoma with secondary CNV in a young male and the long-term results following anti-vascular endothelial growth factor (VEGF) therapy. A 30-year-old male with history of defective vision in both eyes since several years and recent worsening in the right eye (RE) since 2 months was found to have bilateral macular osteoma with CNV in the RE based on clinical evaluation, fluorescein angiography, optical coherence tomography, and ultrasonography. Intravitreal injection of ranibizumab at monthly intervals for three doses resulted in resolution of CNV and remained stable for 5 years. Recurrent CNV detected 6 years later responded to an injection of intravitreal bevacizumab and has remained stable till date. Anti-VEGF therapy stabilized the secondary CNV in our patient for 7 years with satisfactory structural and functional outcome, demonstrating the long-term efficacy of this modality of treatment.

11.
Spectrochim Acta A Mol Biomol Spectrosc ; 136 Pt C: 1850-6, 2015 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-25467679

RESUMO

Organic nonlinear optical material, l-lysine semi-maleate (l-LSM) single crystals were grown by slow cooling solution growth technique. The crystal system of grown l-LSM was confirmed by single crystal and powder X-ray diffraction analyzes. Functional groups of the grown crystal have been identified by Fourier Transform Infrared spectral analysis. The proton and carbon NMR spectral studies confirm the presence of hydrogen and carbon in the grown l-LSM. The melting and thermal decomposition temperatures of the crystal were determined using thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses. Optical transparency, second harmonic generation efficiency, micro hardness, dielectric constant and loss, refractive index and birefringence have also been measured. Further, the growth patterns and dislocations present in the grown crystal are studied.

12.
J Colloid Interface Sci ; 434: 195-200, 2014 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25203911

RESUMO

Copper oxide based systems are well appreciated for their oxidation activity. The present piece of work discusses the redox properties and catalytic activity of CuO impregnated on mesoporous alumina support. A series of catalysts with copper loading varying from 2.0 to 14 wt% were prepared by deposition precipitation method on meso alumina obtained via surfactant assisted route using dodecylamine. CO oxidation has been taken as the test reaction for investigating the catalytic activity of these systems. The catalysts are characterised by TEM, SEM, XRD, FTIR spectroscopy, DR UV spectroscopy, N2 adsorption-desorption study, ESR spectroscopy and TPR using H2. The characterisations indicated CuO in highly dispersed amorphous state at copper loadings <14 wt% in the samples, and as crystalline phase at higher loadings. Easily reducible well dispersed CuO species favoured the reaction, indicating the decisive role of reducibility of the catalysts in CO oxidation. Almost complete oxidation of CO was affected over the system under the prescribed reaction conditions, and practically nil deactivation was recorded when the reaction was performed over a period of 50h.

13.
Int J Phytoremediation ; 15(8): 789-800, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23819275

RESUMO

The present work was aimed at analysing the role of inoculated microalgae in nutrient dynamics, bioremediation and biomass production of sewage water. Preliminary microscopic analyses of sewage water revealed the presence of different algal groups, with predominance of Cyanophyta. Among the inoculated strains, Calothrix showed highest dry cell weight (916.67 mg L(-1)), chlorophyll and carotenoid content in tap water + sewage water (1:1) treatment. Significant removal of NO3-N ranging from 57-78% and PO4-P (44-91%) was recorded in microalgae inoculated tap water + sewage water. The total dissolved solids and electrical conductivity of tap water + sewage water after incubation with Calothrix sp. decreased by 28.5 and 28.0%, accompanied by an increase in dissolved oxygen from 4.4 to 6.4 mg L(-1) on the 20th day. Our investigation revealed the robustness of Calothrix sp. in sequestering nutrients (N and P), improving water quality and proliferating in sewage water.


Assuntos
Clorófitas/fisiologia , Cianobactérias/fisiologia , Diatomáceas/fisiologia , Microalgas/fisiologia , Esgotos/análise , Eliminação de Resíduos Líquidos , Biodegradação Ambiental , Biodiversidade , Biomassa , Carotenoides/metabolismo , Clorofila/metabolismo , Clorófitas/citologia , Clorófitas/crescimento & desenvolvimento , Cianobactérias/citologia , Cianobactérias/crescimento & desenvolvimento , Cianobactérias/isolamento & purificação , Diatomáceas/citologia , Diatomáceas/crescimento & desenvolvimento , Diatomáceas/isolamento & purificação , Microalgas/citologia , Microalgas/crescimento & desenvolvimento , Microalgas/isolamento & purificação , Nitrogênio/metabolismo , Fósforo/metabolismo , Água/normas
14.
Phytopathology ; 103(7): 750-61, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23464902

RESUMO

Genetic and phenotypic diversity and population differentiation of Sclerotinia sclerotiorum isolates infecting canola from China and the United States were investigated. Genetic diversity was assessed with eight microsatellite markers and mycelial compatibility groups (MCGs). Phenotypic diversity was assessed with sensitivity to three fungicides, production of oxalate and sclerotia, growth rate, and virulence on two canola cultivars. No shared MCGs or multilocus haplotypes were detected between the two populations, and populations differed significantly (P < 0.001). Recombination was detected in both populations but was greater in the Chinese population. A polymerase chain reaction detection assay showed that ~60% of the isolates were inversion-plus at the mating type locus. The two populations differed significantly (P < 0.05) for all of the phenotypic traits except for sensitivity to fungicide fluazinam and virulence. Isolates in the Chinese population were unique in several aspects. Despite the phenotypic differentiation, heritabilities of the phenotypic traits were similar for both populations. Significant correlations were found among five phenotypic traits. Cross resistance to benomyl and iprodione was detected. Virulence was not significantly correlated with any other phenotypic trait and had the least heritability. However, both populations were equally virulent on either a susceptible or a moderately resistant canola cultivars.


Assuntos
Ascomicetos/genética , Brassica napus/microbiologia , Fungicidas Industriais/farmacologia , Variação Genética , Repetições de Microssatélites/genética , Doenças das Plantas/microbiologia , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacologia , Ascomicetos/efeitos dos fármacos , Ascomicetos/isolamento & purificação , Ascomicetos/patogenicidade , Benomilo/farmacologia , Biomassa , China , Genes Fúngicos Tipo Acasalamento/genética , Genética Populacional , Haplótipos , Hidantoínas/farmacologia , Micélio , Oxalatos/metabolismo , Fenótipo , Pigmentos Biológicos , Recombinação Genética , Estados Unidos , Virulência
15.
Acta Crystallogr Sect E Struct Rep Online ; 69(Pt 11): o1608, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-24526934

RESUMO

In the title compound, C19H14FNS2, the seven-membered thia-zepine ring adopts a slightly distorted twist boat conformation. The dihedral angle between the benzene rings is 53.6 (1)°. The mean plane of the thia-zepine ring is twisted by 34.3 (7)° and 36.6 (7)° from the benezene rings. A C-H⋯F interaction generates stacking of molecules along the ab plane.

16.
Biochimie ; 93(6): 1028-36, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21356265

RESUMO

Amongst sulfonylureas, gliclazide is one of the mostly prescribed drugs to diabetic patients and is metabolized extensively by P450 CYP2C9. Among 24-CYP2C9 alleles, the *2/*2 and *3/*3 genotypes showed significantly lower gliclazide clearances with reductions of 25 and 57%, respectively. However, the reason for the change in drug-metabolizing activity induced by these natural alleles is unknown. In the present study, we used molecular dynamics simulation and autodocking studies to provide models for gliclazide-bound complexes of CYP2C9*2, *3 and *2/*3 mutants, which give insight into CYP2C9-gliclazide interactions and explain the reduced enzymatic activity seen in these variants. Our data shows that the size of the substrate-access entry site is significantly reduced in mutants, which limits the access of gliclazide to heme and the active site. The distance from the substrate oxidation site and heme is >5Å in *3 and *2/*3. Therefore, the addition of an active oxygen molecule by heme-Fe is hindered. The absence of F100, F114 and F476 in the interacting amino acid pocket in *3 reduces catalytic efficiency toward gliclazide. In *1, gliclazide is stabilized by the formation of two hydrogen bonds with R108 while it is absent in mutants. Further in *3 and *2/*3, the key heme-stabilizing residue, R97 stabilization is greatly reduced. Therefore, the decreased catalytic activity of these variants can be explained from the reduced access of the gliclazide to heme, and the interaction between heme and substrate is affected due to their instability in the active site.


Assuntos
Hidrocarboneto de Aril Hidroxilases/química , Gliclazida/química , Hipoglicemiantes/química , Simulação de Dinâmica Molecular , Alelos , Hidrocarboneto de Aril Hidroxilases/genética , Hidrocarboneto de Aril Hidroxilases/metabolismo , Sítios de Ligação , Biocatálise , Domínio Catalítico , Citocromo P-450 CYP2C9 , Estabilidade Enzimática , Genótipo , Gliclazida/metabolismo , Heme/química , Humanos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Hidroxilação , Hipoglicemiantes/metabolismo , Mutação , Fenilalanina/química , Ligação Proteica , Estrutura Terciária de Proteína
17.
Org Lett ; 11(18): 4060-3, 2009 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-19739684

RESUMO

The attempted generation of the potentially aromatic 6,7-diphenyldibenzo[e,g][1,4]diazocine dianion from sodium in THF leads with profound rearrangement to the isomeric N-(2-amino-1,2-diphenylethenyl)carbazole dianions and, after hydrolysis, to a 55:45 mixture of Z- and E-isomers of N-(2-amino-1,2-diphenylethenyl)carbazoles. These isomers were separated and their individual structures determined by X-ray diffraction. Since treatment of the starting diazocine first with tert-butyllithium and then with water also yielded the same Z- and E-isomeric mixture, electron transfer reduction is clearly involved.

18.
Plant Dis ; 93(8): 797-803, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30764325

RESUMO

The taxonomy of the powdery mildew fungus infecting lentil in the Pacific Northwest (PNW) of the United States was investigated on the basis of morphology and rDNA internal transcribed spacer (ITS) sequences. Anamorphic characters were in close agreement with descriptions of Erysiphe trifolii. However, teleomorphs formed chasmothecial appendages with highly branched apices, whereas E. trifolii has been described as producing flexuous or sometimes loosely branched appendages. Branched appendages have been described in Erysiphe diffusa, a fungus reported from species of Lens, Glycine, and Sophora, raising the possibility that the PNW fungus could be E. diffusa. Examination of morphological characters of an authentic specimen of E. trifolii from Austria determined that it included chasmothecial appendages resembling those seen in PNW specimens. Furthermore, ITS sequences from five powdery mildew samples collected from lentils in PNW greenhouses and fields from 2006 to 2008 were identical to one another, and exhibited higher similarity to sequences of E. trifolii (99%) than to those of any other Erysiphe spp. available in GenBank. Parsimony analysis grouped the lentil powdery mildew into a clade with Erysiphe baeumleri, E. trifolii, and E. trifolii-like Oidium sp., but indicated a more distant relationship to E. diffusa. In greenhouse inoculation studies, the lentil powdery mildew fungus did not infect soybean genotypes known to be susceptible to E. diffusa. The pathogenicity of E. trifolii on lentil was confirmed using modified Koch's postulates. This is the first report of E. trifolii infecting lentil. E. diffusa and E. trifolii have different host ranges, so the discovery of E. trifolii on lentil has implications both for determining species of powdery mildews on cool-season grain legumes, and in disease management.

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