Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Int J Biol Macromol ; 263(Pt 2): 130517, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38423444

RESUMO

Orally targeted delivery systems have attracted ample interest in colorectal cancer management. In this investigation, we developed Inositol hexaphosphate (IHP) loaded Tripolyphosphate (Tr) crosslinked Pectin (Pe) Chitosan (Ch) nanoparticles (IHP@Tr*Pe-Ch-NPs) and modified them with l-Carnitine (CE) (CE-IHP@Tr*Pe-Ch-NPs) to improve uptake in colon cells. The formulated CE-IHP@Tr*Pe-Ch-NPs displayed a monodisperse distribution with 219.3 ± 5.5 nm diameter and 30.17 mV surface charge. Cell-line studies revealed that CE-IHP@Tr*Pe-Ch-NPs exhibited excellent biocompatibility in J774.2 and decreased cell viability in DLD-1, HT-29, and MCF7 cell lines. More cell internalization was seen in HT-29 and MCF7 due to overexpression of the OCTN2 and ATB0,+ transporter (CE transporters) compared to DLD-1. The cell cycle profile, reactive oxygen species, apoptosis, and mitochondrial membrane potential assays were performed to explore the chemo-preventive mechanism of CE-IHP@Tr*Pe-Ch-NPs. Moreover, the in-silico docking studies revealed enhanced interactive behavior of CE-IHP@Tr*Pe-Ch-NPs, thereby proving their targeting ability. All the findings suggested that CE-IHP@Tr*Pe-Ch-NPs could be a promising drug delivery approach for colon cancer targeting.


Assuntos
Quitosana , Nanopartículas , Humanos , Ácido Fítico , Pectinas/farmacologia , Carnitina , Células MCF-7 , Colo , Portadores de Fármacos
2.
Int J Biol Macromol ; 256(Pt 2): 127964, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37951423

RESUMO

Doxorubicin is a powerful chemotherapy medicine that is frequently used to treat cancer, but because of its extremely destructive side effects on other healthy cells, its applications have been severely constrained. With the aim of using lower therapeutic doses of doxorubicin while maintaining the same anti-cancerous activity as those of higher doses, the present study designs nano-encapsulation of doxorubicin by acrylamide grafted melanin as core and acrylic acid grafted flax seed gum as shell (DOX@AAM-g-ML/AA-g-FSG-NPs) for studies in-vivo and in-vitro anticancer activity. For biological studies, the cytotoxicity of DOX@AAM-g-ML/AA-g-FSG-NPs was examined on a cancerous human cell line (HCT-15) and it was observed that DOX@AAM-g-ML/AA-g-FSG-NPs exhibited very high toxicity towards HCT-15. In-vivo investigation in colon cancer-inflicted rat model also showed that DOX@AAM-g-ML/AA-g-FSG-NPs showed better anticancer activity against cancerous cells as compared to free doxorubicin. The drug release behavior of DOX@GML-GFS-NPs was studied at several pH and maximum drug release (95 %) was recorded at pH -7.2, and kinetic data of drug release was follows the Higuchi (R2 = 0.9706) kinetic model. Our study is focussed on reducing the side effects of doxorubicin by its nano-encapsulation in acrylamide grafted melanin as core and acrylic acid grafted flax seed gum that will also enhance its efficiency.


Assuntos
Acrilatos , Linho , Nanopartículas , Neoplasias , Ratos , Humanos , Animais , Melaninas , Nanopartículas/uso terapêutico , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Neoplasias/tratamento farmacológico , Acrilamidas , Portadores de Fármacos , Sistemas de Liberação de Medicamentos
3.
Crit Care Clin ; 39(4): 675-687, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37704333

RESUMO

Perioperative morbidity and mortality are significantly associated with both static and dynamic perioperative factors. The studies investigating static perioperative factors have been reported; however, there are a limited number of previous studies and data sets analyzing dynamic perioperative factors, including physiologic waveforms, despite its clinical importance. To fill the gap, the authors introduce a novel large size perioperative data set: Machine Learning Of physiologic waveforms and electronic health Record Data (MLORD) data set. They also provide a concise tutorial on machine learning to illustrate predictive models trained on complex and diverse structures in the MLORD data set.


Assuntos
Registros Eletrônicos de Saúde , Aprendizado de Máquina , Humanos , Relevância Clínica
4.
Neoplasia ; 42: 100911, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37269818

RESUMO

Early detection of lung cancer is critical for improvement of patient survival. To address the clinical need for efficacious treatments, genetically engineered mouse models (GEMM) have become integral in identifying and evaluating the molecular underpinnings of this complex disease that may be exploited as therapeutic targets. Assessment of GEMM tumor burden on histopathological sections performed by manual inspection is both time consuming and prone to subjective bias. Therefore, an interplay of needs and challenges exists for computer-aided diagnostic tools, for accurate and efficient analysis of these histopathology images. In this paper, we propose a simple machine learning approach called the graph-based sparse principal component analysis (GS-PCA) network, for automated detection of cancerous lesions on histological lung slides stained by hematoxylin and eosin (H&E). Our method comprises four steps: 1) cascaded graph-based sparse PCA, 2) PCA binary hashing, 3) block-wise histograms, and 4) support vector machine (SVM) classification. In our proposed architecture, graph-based sparse PCA is employed to learn the filter banks of the multiple stages of a convolutional network. This is followed by PCA hashing and block histograms for indexing and pooling. The meaningful features extracted from this GS-PCA are then fed to an SVM classifier. We evaluate the performance of the proposed algorithm on H&E slides obtained from an inducible K-rasG12D lung cancer mouse model using precision/recall rates, Fß-score, Tanimoto coefficient, and area under the curve (AUC) of the receiver operator characteristic (ROC) and show that our algorithm is efficient and provides improved detection accuracy compared to existing algorithms.


Assuntos
Algoritmos , Neoplasias Pulmonares , Animais , Camundongos , Neoplasias Pulmonares/diagnóstico , Aprendizado de Máquina , Resultado do Tratamento , Pulmão
5.
Int J Pharm ; 639: 122937, 2023 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-37068717

RESUMO

Polysaccharide-based nanoparticles (NPs) such as pectin/ chitosan (PN/CN) had always been of greatest interest because of their excellent solubility, biocompatibility, and higher suitability for oral drug delivery. This study employed blending-crosslinking of polymers (PN&CN) followed by emulsification-solvent evaporation to prepare and compare two sets of PEGylated NPs to deliver phytic acid (IP6) to colon orally as it has potential to manage colon cancer but fails to reach colon when ingested in pure form. The first set was crosslinked with Glutaraldehyde (GE) (GE*PN-CN-NPs) while the second set was crosslinked with sodium tripolyphosphate (TPP) (TPP*PN-CN-NPs). IP6-loaded-GE/TPP*PN-CN-NPs were optimized using a central composite design. Developed TPP*PN-CN-NPs had a smaller size (210.6 ± 7.93 nm) than GE*PN-CN-NPs (557.2 ± 5.027 nm). Prepared NPs showed <12% IP6 release at pH 1.2 whereas >80% release was observed at pH 7.4. Further, NPs were explored for cytocompatibility in J774.2 cell lines, cytotoxicity, and cellular uptake in HT-29 and DLD-1 cell lines. While exhibiting substantial cytotoxicity and cellular uptake in HT-29 and DLD-1, the NPs were deemedsafe in J774.2. The PEGylated-TPP*PN-CN-NPs showed time-dependent uptake in J774.2 cell lines. Conclusively, the employed NP development method successfully delivered IP6 to colon and may also open avenues for the oral delivery of other drugs to colon.


Assuntos
Quitosana , Nanopartículas , Ácido Fítico , Pectinas , Colo , Polietilenoglicóis , Portadores de Fármacos
6.
Drug Deliv Transl Res ; 13(2): 627-641, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-35963927

RESUMO

Rheumatoid arthritis (RA) is a joint ailment with multi-factorial immune-mediated degenerative pathogenesis, including genetic and environmental defects. Resistance to disease-modifying anti-rheumatic drugs (DMARDs) happens due to excessive drug efflux over time, rendering the concentration insufficient to elicit a response. Thymoquinone (TQ) is a quinone-based phenolic compound with antioxidant and anti-inflammatory activities that downregulate numerous pro-inflammatory cytokines. However, its pharmaceutical importance and therapeutic utility are underexplored due to intrinsic physicochemical characteristics such as inadequate biological stability, short half-life, low hydrophilicity, and less systemic availability. Tamanu oil-stabilised nanostructured lipid carriers (TQ-NLCs) were prepared and optimised using Box-Behnken design (BBD) with the size of 153.9 ± 0.52 nm and surface charge of -30.71 mV. The % entrapment efficiency and drug content were found to be 84.6 ± 0.50% and 14.75 ± 0.52%, respectively. Furthermore, the TQ-loaded NLCs (TQ-NLCs) assayed for skin permeation for transdermal delivery which significantly (p < 0.05) increased skin enhancement ratio 14.6 times compared to the aqueous solution of TQ. Tamanu oil displayed the synergistic anti-inflammatory potential with TQ in comparison to pure TQ, as evidenced against carrageenan (CRG)-induced paw oedema model and Freund's adjuvant-induced arthritic model. The arthritic and X-ray scores significantly (p < 0.05) reduced in TQ-NLCs and standard formulation-treated groups. Moreover, serum pro-inflammatory marker TNF-α and IL-6 levels were also significantly (p < 0.05) reduced in TQ-NLCs gel-treated group compared to the arthritic control group.


Assuntos
Antirreumáticos , Artrite Reumatoide , Anti-Inflamatórios/farmacologia , Artrite Reumatoide/tratamento farmacológico , Regulação para Baixo , Portadores de Fármacos/química , Interleucina-6 , Quinonas/uso terapêutico , Fator de Necrose Tumoral alfa/metabolismo , Animais
7.
J Liposome Res ; 33(2): 154-169, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35930249

RESUMO

Some breast cancers are caused by hormonal imbalances, such as estrogen and progesterone. These hormones play a function in directing the growth of cancer cells. The hormone receptors in hormone receptor-positive breast cancer lead breast cells to proliferate out of control. Cancer therapy such as hormonal, targeted, radiation is still unsatisfactory because of these challenges namely multiple drug resistance (MDR), off-targeting, severe adverse effects. A novel aromatase inhibitor exemestane (Exe) exhibits promising therapy in breast cancer. This study aims to develop and optimize Exe-loaded lipid nanocapsules (LNCs) by using DSPC, PF68 and olive oil as lipid, surfactant and oil phase, respectively and to characterize the same. The prepared nanocapsules were investigated via in vitro cell culture and in vivo animal models. The LNCs exhibited cytotoxicity in MCF-7 cell lines and enhanced anti-cancer activity and reduced cardiotoxicity in DMBA-induced animal model when compared to the drug. Additionally, in vivo pharmacokinetics revealed a 4.2-fold increased oral bioavailability when compared with Exe suspension. This study demonstrated that oral administration of Exe-loaded LNCs holds promise for the antiestrogenic activity of exemestane in breast cancer.


Assuntos
Nanocápsulas , Neoplasias , Animais , Lipossomos , Androstadienos/farmacologia , Androstadienos/uso terapêutico , Lipídeos , Neoplasias/tratamento farmacológico
8.
Colloids Surf B Biointerfaces ; 218: 112763, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35994989

RESUMO

This study was designed to create surface-functionalized bosutinib liposomes that could be used for the management of estrogen-positive cancers. The novelty of this work was the anti-cancer activity of bosutinib-loaded liposomes (Bos-LPs) in estrogen-positive cancer via estrogen response elements, responsible for the malignancy of cancer cells. Biotin effectively delivers active moiety to tumor tissues because it interacts with the biotin receptor and operates through the Sodium-dependent multivitamin transporters (SMVT) transporter. The prepared liposomes had a 257.73 ± 4.50 nm particle size, - 28.07 ± 5.81 mV zeta potential, 87.78 ± 1.16 % encapsulation efficiency and 85.56 ± 0.95 % drug release for 48 h. The surface architecture of biotin-modified bosutinib-loaded liposomes (b-Bos-LPs) was confirmed using scanning electron and transmission electron microscopies. In-vitro experiments revealed that b-Bos-LPs outperformed Bos and Bos-LPs in terms of significantly reduced cell viability in MCF-7 cells. According to biodistribution and pharmacokinetic studies, b-Bos-LPs have a higher Bos concentration in tumor tissues as compared to the other organs and also possess better pharmacokinetic activity, indicating that they can be used to treat carcinogen-induced estrogen-positive cancers. This is the first study to show that b-Bos-LPs can display activity against estrogen-positive cancer via biotin targeting. As evidenced by various parameters, b-Bos-LPs showed improved anticancer targeting, therapeutic safety and efficacy in carcinogen-induced estrogen-positive cancer. The receptor protein estrogen, which is primarily responsible for this cancer was downregulated by b-Bos-LPs in an immunoblotting assay. The results showed that biotinylated distearoylphosphatidylcholine (DSPC) augmented LPs loaded with Bosutinib can cause apoptosis in estrogen-positive breast cancer and be an effective way to treat estrogen-positive cancer.


Assuntos
Compostos de Anilina , Neoplasias da Mama , Lipossomos , Nitrilas , Quinolinas , Compostos de Anilina/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Linhagem Celular Tumoral , Sistemas de Liberação de Medicamentos , Estrogênios/metabolismo , Feminino , Humanos , Nitrilas/uso terapêutico , Tamanho da Partícula , Quinolinas/uso terapêutico
9.
EMBO Mol Med ; 14(9): e14891, 2022 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-35811493

RESUMO

There is an increasing need to develop biological anti-inflammatory agents that are more targeted, effective, and with lesser side effects as compared to conventional chemical drugs. In the present study, we found that Mycobacterium tuberculosis protein PPE2 and a synthetic derivative peptide can suppress the mast cell population and inhibit several vasoactive and fibrogenic mediators and pro-inflammatory cytokines induced by mast cells in formalin-induced tissue injury. PPE2 was found to inhibit transcription from the promoter of stem cell factor, important for mast cell maintenance and migration. Thus, PPE2/peptide can be used as a potent nonsteroidal therapeutic agent for the treatment of inflammation and tissue injury.


Assuntos
Mycobacterium tuberculosis , Citocinas/metabolismo , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Mastócitos/metabolismo , Peptídeos/metabolismo , Fator de Células-Tronco/metabolismo , Fator de Células-Tronco/farmacologia
10.
FEBS J ; 289(14): 4146-4171, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35073464

RESUMO

Mycobacterium tuberculosis, the bacterium responsible for tuberculosis, is one of the most successful pathogens in human history. An extremely resilient cell wall and highly evolved and coordinated strategies for immune evasion have made it a very formidable pathogen. The secretory proteins of M. tuberculosis play a crucial role in its virulence and immune evasion. The secretory proteins are secreted through tightly regulated secretion systems and modulate the host immune responses through a plethora of strategies, including epigenetic reprogramming of infected cells, targeting antigen presentation, inhibition of phagosomal maturation, modulation of cytokine production, apoptosis and redox regulation, etc. Upon infection, the secretory proteins become localized into various cellular organelles, such as nucleus, cytoplasm, phagosomes and Golgi, bodies and hijack the host machineries through their wide gamut of functions, including kinase, phosphatase, methyl transferase activities and interaction with several host partners. In this review, we discuss the secretion systems, the functions of various secretory proteins of M. tuberculosis and their roles in modulating immune responses of the host. We also discuss the feasibility of their use as possible therapeutic targets. This information is likely to improve our understanding of the host-pathogen interaction and help in the design of effective anti-tuberculosis therapeutics.


Assuntos
Mycobacterium tuberculosis , Tuberculose , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Interações Hospedeiro-Patógeno , Humanos , Imunidade , Macrófagos/metabolismo , Mycobacterium tuberculosis/metabolismo , Fagossomos/metabolismo , Tuberculose/tratamento farmacológico , Tuberculose/metabolismo
11.
Drug Deliv Transl Res ; 12(7): 1640-1658, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-34476764

RESUMO

There is a curious case in Alveolar macrophages (AM), the frontline defence recruits that contain the spread of all intruding bacteria. In response to Mycobacterium tuberculosis (M.tb), AM either contain the spread or are modulated by M.tb to create a region for their replication. The M.tb containing granulomas so formed are organised structures with confined boundaries. The limited availability of drugs inside AM aid drug tolerance and poor therapeutic outcomes in diseases like tuberculosis. The present work proves the glycotargeting efficiency of levofloxacin (LVF) to AM. The optimised formulation developed displayed good safety with 2% hemolysis and a viability of 61.14% on J774A.1 cells. The physicochemical characterisations such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) proved that carubinose linkage was accomplished and LVF is entrapped inside carubinose-linked hybrid formulation (CHF) and hybrid formulation (HF) in amorphous form. The transmission electron microscopy (TEM) images revealed a core-shell structure of HF. The particle size of 471.5 nm estimated through dynamic light scattering (DLS) is enough to achieve active and passive targeting to AM. The nanoparticle tracking analysis (NTA) data revealed that the diluted samples were free from aggregates. Fluorescence-activated cell sorting (FACS) data exhibited excellent uptake via CHF (15 times) and HF(3 times) with reference to plain fluorescein isothiocyanate (FITC). The pharmacokinetic studies revealed that CHF and HF release the entrapped moiety LVF in a controlled manner over 72 h. The stability studies indicated that the modified formulation remains stable over 6 months at 5 ± 3℃. Hence, hybrid systems can be efficiently modified via carubinose to target AM via the parenteral route.


Assuntos
Fluoroquinolonas , Nanopartículas , Varredura Diferencial de Calorimetria , Macrófagos Alveolares , Nanopartículas/química , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
12.
Pharmaceutics ; 13(6)2021 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-34067322

RESUMO

Cancer causes a considerable amount of mortality in the world, while arthritis is an immunological dysregulation with multifactorial pathogenesis including genetic and environmental defects. Both conditions have inflammation as a part of their pathogenesis. Resistance to anticancer and disease-modifying antirheumatic drugs (DMARDs) happens frequently through the generation of energy-dependent transporters, which lead to the expulsion of cellular drug contents. Thymoquinone (TQ) is a bioactive molecule with anticancer as well as anti-inflammatory activities via the downregulation of several chemokines and cytokines. Nevertheless, the pharmacological importance and therapeutic feasibility of thymoquinone are underutilized due to intrinsic pharmacokinetics, including short half-life, inadequate biological stability, poor aqueous solubility, and low bioavailability. Owing to these pharmacokinetic limitations of TQ, nanoformulations have gained remarkable attention in recent years. Therefore, this compilation intends to critically analyze recent advancements in rheumatoid arthritis and cancer delivery of TQ. This literature search revealed that nanocarriers exhibit potential results in achieving targetability, maximizing drug internalization, as well as enhancing the anti-inflammatory and anticancer efficacy of TQ. Additionally, TQ-NPs (thymoquinone nanoparticles) as a therapeutic payload modulated autophagy as well as enhanced the potential of other drugs when given in combination. Moreover, nanoformulations improved pharmacokinetics, drug deposition, using EPR (enhanced permeability and retention) and receptor-mediated delivery, and enhanced anti-inflammatory and anticancer properties. TQ's potential to reduce metal toxicity, its clinical trials and patents have also been discussed.

13.
J Immunol ; 205(11): 3095-3106, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33148716

RESUMO

Iron is an essential element for Mycobacterium tuberculosis; it has at least 40 enzymes that require iron as a cofactor. Accessibility of iron at the phagosomal surface inside macrophage is crucial for survival and virulence of M. tuberculosis ESAT-6, a 6-kDa-secreted protein of region of difference 1, is known to play a crucial role in virulence and pathogenesis of M. tuberculosis In our earlier study, we demonstrated that ESAT-6 protein interacts with ß-2-microglobulin (ß2M) and affects class I Ag presentation through sequestration of ß2M inside endoplasmic reticulum, which contributes toward inhibition of MHC class I:ß2M:peptide complex formation. The 6 aa at C-terminal region of ESAT-6 are essential for ESAT6:ß2M interaction. ß2M is essential for proper folding of HFE, CD1, and MHC class I and their surface expression. It is known that M. tuberculosis recruit holotransferrin at the surface of the phagosome. But the upstream mechanism by which it modulates holotransferrin-mediated iron uptake at the surface of macrophage is not well understood. In the current study, we report that interaction of the ESAT-6 protein with ß2M causes downregulation of surface HFE, a protein regulating iron homeostasis via interacting with transferrin receptor 1 (TFR1). We found that ESAT-6:ß2M interaction leads to sequestration of HFE in endoplasmic reticulum, causing poorer surface expression of HFE and HFE:TFR1 complex (nonfunctional TFR1) in peritoneal macrophages from C57BL/6 mice, resulting in increased holotransferrin-mediated iron uptake in these macrophages. These studies suggest that M. tuberculosis probably targets the ESAT-6 protein to increase iron uptake.


Assuntos
Antígenos de Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Regulação para Baixo/fisiologia , Proteína da Hemocromatose/metabolismo , Macrófagos Peritoneais/metabolismo , Mycobacterium tuberculosis/metabolismo , Transferrina/metabolismo , Animais , Transporte Biológico/fisiologia , Retículo Endoplasmático/metabolismo , Ferro/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Receptores da Transferrina/metabolismo , Virulência/fisiologia , Microglobulina beta-2/metabolismo
14.
J Microencapsul ; 36(5): 432-446, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31238752

RESUMO

The present study was aimed at preparing and evaluating levocetirizine (LCZD) loaded emulgel containing tamanu oil and sericin for atopic dermatitis (AD) therapy. The emulgel envisaged topical delivery of LCZD utilising natural antioxidants for superior therapeutic outcomes when compared with other conventional therapy. Tamanu oil based microemulsion (ME) was optimised utilising Box-Behnken design (BBD). The OPT-ME displayed globule size 379.5 ± 2.33 nm, polydispersity index 0.284, drug loading 0.41 ± 0.01% w/w, entrapment efficiency 94.34 ± 2.11% w/w and drug release 86.24 ± 4.90% respectively over a period of 24 h. The optimised formulation (OPT-ME) was further incorporated into sericin gel to form emulgel (LSE). In vivo pharmacodynamic studies revealed enhanced therapeutic potential of emulgel in terms of reduced scratching frequency and erythema score when compared with conventional gel. The superior therapeutic potential was further witnessed through histopathological and biochemical studies. The emulgel can be an alternative appropriate dosage form for the treatment of AD.


Assuntos
Cetirizina/administração & dosagem , Dermatite Atópica/tratamento farmacológico , Emulsões/química , Óleos de Plantas/química , Sericinas/química , Animais , Bombyx/química , Calophyllum/química , Cetirizina/farmacocinética , Cetirizina/uso terapêutico , Chlorocebus aethiops , Dermatite Atópica/induzido quimicamente , Dermatite Atópica/patologia , Dinitroclorobenzeno , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Feminino , Masculino , Ratos Wistar , Absorção Cutânea , Células Vero
15.
Biochim Biophys Acta Proteins Proteom ; 1867(3): 163-174, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30543875

RESUMO

Acyl carrier proteins (ACPs) play crucial roles in the biosynthesis of fatty acids, non-ribosomal polypeptides and polyketides. The three-dimensional NMR structure of Leishmania major holo-LmACP, belonging to the type II pathway, has been reported previously, but the structure of its apo-form and its conformational differences with the holo-form remain to be explored. Here we report the crystal structures of apo-LmACP (wild-type and S37A mutant) at 2.0 Šresolution and compare their key features with the structures of holo-LmACP (wild-type) and other type II ACPs from Escherichia coli and Plasmodium falciparum. The crystal structure of apo-LmACP, which is homologous to other type II ACPs, displays some key structural rearrangements as compared to its holo-structure. Contrary to holo-form, which exists predominantly as a monomer, the apo-form exists as a mixture of monomeric and dimeric population in solution. In contrast to the closed structure of apo-LmACP, holo-LmACP structure was observed in an open conformation as a result of reorganization of specific helices and loops. We propose that the structural changes exhibited by LmACP occur due to the attachment of the phosphopantetheine arm and may be a prerequisite for the initiation of fatty acid synthesis. The movement of helix 3 may also play a role in the dissociation of holo-LmACP from its cognate enzymes of the FAS II pathway.


Assuntos
Proteína de Transporte de Acila/química , Proteínas de Protozoários/química , Cristalização , Leishmania major , Modelos Moleculares , Conformação Proteica
16.
Biol Trace Elem Res ; 186(1): 154-161, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29550952

RESUMO

The aim of the study was to assess the effect of inorganic vanadium (V) supplementation on antioxidant enzymes, immune status, and haemato-biochemical attributes of growing crossbred calves. Twenty-four male Karan Fries calves (Tharparkar × Holstein Friesian) (initial body mass 72.83 ± 2.5 kg; age 3-9 month) were randomly allocated to four groups: the control (received basal diet devoid of supplemental V), the 3 ppm (received basal diet with 3 mg/kg V), the 6 ppm (received basal diet with 6 mg/kg V) and the 9 ppm group (received basal diet with 9 mg/kg V). All the calves were fed for 150 days as per ICAR (2013) feeding standards to meet their nutrient requirements for 500 g growth rate/day. Peripheral blood samples were collected at the start of experiment and subsequently at 30, 60, 90, 120 and 150 days post-V supplementation for determination of antioxidant enzyme activity, immunological parameters and haemato-biochemical attributes. Results indicated that dietary supplementation of V did not affect daily gain, feed intake and haematological parameters. Crossbred calves fed with 9 mg V/kg diet showed reduced (P < 0.05) plasma total cholesterol concentration; however, plasma total protein and glucose concentration remained unaltered. Glutathione peroxidase (GPx) activity as well as immunoglobulin G (IgG) concentration was significantly (P < 0.05) higher in group supplemented with 9 mg V/kg DM; however, superoxide dismutase (SOD), catalase activity and total plasma immunoglobulin (Ig) concentration were similar in all experimental group. Dietary V supplementation showed a negative relation with plasma thiobarbituric acid reactive substances (TBARS) concentration, whereas non-esterified fatty acid (NEFA) concentration remained unaltered among all groups. Plasma V level increased (P < 0.05) with increasing dietary V levels without affecting levels of Ca, Mg, Fe, Cu and Zn. In conclusion, a dietary addition of 9 mg V/kg DM reduced cholesterol content and improved antioxidant and immune response in growing crossbred calves.


Assuntos
Antioxidantes/metabolismo , Colesterol/metabolismo , Cromo/farmacologia , Glutationa Peroxidase/sangue , Imunoglobulina G/sangue , Animais , Bovinos , Colesterol/sangue , Cromo/administração & dosagem , Cromo/sangue , Suplementos Nutricionais , Glutationa Peroxidase/metabolismo , Imunoglobulina G/imunologia
17.
Sci Rep ; 3: 3001, 2013 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-24141523

RESUMO

Soil salinity problems are widespread around the globe with increased risk of spreading over the years. The fungus Piriformospora indica, identified in Indian Thar desert, colonizes the roots of monocotyledon plants and provides resistance towards biotic as well as abiotic stress conditions. We have identified a cyclophilin A-like protein from P. indica (PiCypA), which shows higher expression levels during salinity stress. The transgenic tobacco plants overexpressing PiCypA develop osmotic tolerance and exhibit normal growth under osmotic stress conditions. The crystal structure and NMR spectroscopy of PiCypA show a canonical cyclophilin like fold exhibiting a novel RNA binding activity. The RNA binding activity of the protein and identification of the key residues involved in the RNA recognition is unique for this class of protein. Here, we demonstrate for the first time a direct evidence of countering osmotic stress tolerance in plant by genetic modification using a P. indica gene.


Assuntos
Basidiomycota/genética , Ciclofilina A/genética , Proteínas Fúngicas/genética , Plantas/genética , Plantas/metabolismo , Proteínas de Ligação a RNA/genética , Tolerância ao Sal/genética , Estresse Fisiológico , Adaptação Biológica , Ciclofilina A/química , Proteínas Fúngicas/química , Expressão Gênica , Ordem dos Genes , Marcação de Genes , Modelos Moleculares , Estresse Oxidativo , Fenótipo , Plantas Geneticamente Modificadas , Ligação Proteica , Conformação Proteica , RNA/química , RNA/metabolismo , Proteínas de Ligação a RNA/química , Plântula , Nicotiana/genética , Nicotiana/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA