Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 71
Filtrar
Mais filtros

Bases de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
J Biol Chem ; 300(8): 107496, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38925325

RESUMO

Emerging Artemisinin (ART) resistance in Plasmodium falciparum (Pf) poses challenges for the discovery of novel drugs to tackle ART-resistant parasites. Concentrated efforts toward the ART resistance mechanism indicated a strong molecular link of ART resistance with upregulated expression of unfolded protein response pathways involving Prefoldins (PFDs). However, a complete characterization of PFDs as molecular players taking part in ART resistance mechanism, and discovery of small molecule inhibitors to block this process have not been identified to date. Here, we functionally characterized all Pf Prefoldin subunits (PFD1-6) and established a causative role played by PFDs in ART resistance by demonstrating their expression in intra-erythrocytic parasites along with their interactions with Kelch13 protein through immunoprecipitation coupled MS/MS analysis. Systematic biophysical interaction analysis between all subunits of PFDs revealed their potential to form a complex. The role of PFDs in ART resistance was confirmed in orthologous yeast PFD6 mutants, where PfPFD6 expression in yeast mutants reverted phenotype to ART resistance. We identified an FDA-approved drug "Biperiden" that restricts the formation of Prefoldin complex and inhibits its interaction with its key parasite protein substrates, MSP-1 and α-tubulin-I. Moreover, Biperiden treatment inhibits the parasite growth in ART-sensitive Pf3D7 and resistant Pf3D7k13R539T strains. Ring survival assays that are clinically relevant to analyze ART resistance in Pf3D7k13R539T parasites demonstrate the potency of BPD to inhibit the growth of survivor parasites. Overall, our study provides the first evidence of the role of PfPFDs in ART resistance mechanisms and opens new avenues for the management of resistant parasites.

2.
Hum Genomics ; 18(1): 7, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38291512

RESUMO

The present study investigated two single nucleotide polymorphisms (SNPs)-rs479200 and rs516651 in the host EGLN1/PHD2 gene for their association with COVID-19 severity. A retrospective cohort of 158 COVID-19 patients from the Indian population (March 2020 to June 2021) was enrolled. Notably, the frequency of C allele (0.664) was twofold higher than T allele (0.336) in severe COVID-19 patients. Here, we report a novel finding that the C allele of rs479200 in the EGLN1 gene imparts a high risk of severe COVID-19 (odds ratio-6.214 (1.84-20.99) p = 0.003; 9.421 (2.019-43.957) p = 0.004), in additive inheritance model (adjusted and unadjusted, respectively).


Assuntos
COVID-19 , Humanos , Alelos , Estudos Retrospectivos , COVID-19/epidemiologia , COVID-19/genética , Polimorfismo de Nucleotídeo Único/genética , Povo Asiático , Predisposição Genética para Doença , Frequência do Gene , Prolina Dioxigenases do Fator Induzível por Hipóxia/genética
3.
Biochemistry ; 63(14): 1738-1751, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-38975628

RESUMO

Over the past two decades, the utilization of protein cages has witnessed exponential growth driven by their extensive applications in biotechnology and therapeutics. In the context of the recent Covid-19 pandemic, protein-cage-based scaffolds played a pivotal role in vaccine development. Beyond vaccines, these protein cages have proven valuable in diverse drug delivery applications thanks to their distinctive architecture and structural stability. Among the various types of protein cages, ferritin-based cages have taken the lead in drug delivery applications. This is primarily attributed to their ease of production, exceptional thermal stability, and nontoxic nature. While ferritin-based cages are commonly employed in anticancer drug delivery and contrast agent delivery, their efficacy in malarial drug delivery had not been explored until this study. In this investigation, several antimalarial drugs were encapsulated within horse spleen ferritin, and the binding and loading processes were validated through both experimental and computational techniques. The data unequivocally demonstrate the facile incorporation of antimalarial drugs into ferritin without disrupting its three-dimensional structure. Computational docking and molecular dynamics simulations were employed to pinpoint the precise location of the drug binding site within ferritin. Subsequent efficacy testing on Plasmodium revealed that the developed nanoconjugate, comprising the drug-ferritin conjugate, exhibited significant effectiveness in eradicating the parasite. In conclusion, the findings strongly indicate that ferritin-based carrier systems hold tremendous promise for the future of antimalarial drug delivery, offering high selectivity and limited side effects.


Assuntos
Antimaláricos , Ferritinas , Ferritinas/química , Ferritinas/metabolismo , Antimaláricos/química , Antimaláricos/farmacologia , Animais , Cavalos , Sistemas de Liberação de Medicamentos/métodos , Malária/tratamento farmacológico , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Humanos , Baço/metabolismo , Plasmodium falciparum/efeitos dos fármacos
4.
Mol Cell ; 77(5): 927-929, 2020 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-32142688
5.
Exp Parasitol ; 243: 108407, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36349579

RESUMO

The emergence of drug-resistant parasites and/or insecticide-resistant mosquito vectors necessitates developing alternative tools that either supplement or replace the conventional malaria control strategies. Trans-infecting the mosquito vector with symbionts that can either compete with a targeted pathogen or manipulate the host biology by reducing its vectorial capacity could be a promising and innovative biological approach for the control of infectious diseases This idea could be utilized to develop a novel and efficient vector control strategy; symbionts are dispersed into vector populations to reduce their ability to transmit human pathogens. Here, we reported the natural existence of Microsporidian (an obligate fungus) in the field-collected An. stephensi mosquito. However, laboratory-reared An. stephensi and An. culicifacies did not exhibit microsporidian infection. Similarly, 16s rRNA PCR identified ∼1kb amplicons in laboratory-reared An. stephensi and An. culicifacies, indicating the presence of naturally residing different bacterial species. DNA sequencing of these amplicons revealed the identities of different bacteria which are not well-characterized in terms of plasmodia-interaction activity in the Indian malaria vector. This article summarizes an overview of the previously studied microbial symbionts for their role in Plasmodium transmission along with a list of new or unexplored symbionts in the disease transmitting mosquito vectors. The summarized information could be utilized to explore such microbial symbionts for their role in Plasmodium-transmission biology in-depth and implementation in the malaria control interventions globally.


Assuntos
Anopheles , Inseticidas , Malária , Animais , Humanos , Mosquitos Vetores , Anopheles/parasitologia , Malária/prevenção & controle , Malária/parasitologia , RNA Ribossômico 16S/genética , Bactérias
6.
Biochem J ; 477(7): 1323-1344, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32202613

RESUMO

Metacaspases are novel cysteine proteases found in apicomplexan whose function is poorly understood. Our earlier studies on Plasmodium falciparum metacaspase-2 (PfMCA-2) revealed that the caspase inhibitor, Z-FA-FMK efficiently inhibited PfMCA-2 activity and, expression, and significantly blocked in vitro progression of the parasite developmental cycle via apoptosis-like parasite death. Building on these findings, we synthesized a set of novel inhibitors based on structural modification of Z-FA-FMK with the amides of piperic acid and investigated their effect on PfMCA-2. One of these analogs, SS-5, specifically inhibited the activity and expression of PfMCA-2. The activities of some other known malarial proteases (falcipains, plasmepsins and vivapain), and human cathepsins-B, D and L, and caspase-3 and -7 were not inhibited by SS-5. SS-5 blocked the development of P. falciparum in vitro (IC50 1 µM) and caused prominent morphological distortions. Incubation with SS-5 led to persistent parasite oxidative stress accompanied by depolarization of mitochondrial potential and accumulation of intracellular Ca2+. SS-5 also inhibited the development of P. berghei in a murine model. Our results suggest that the inhibition of PfMCA-2 results in oxidative stress, leading to apoptosis-like parasite death. Thus, SS-5 offers a starting point for the optimization of new antimalarials, and PfMCA-2 could be a novel target for antimalarial drug discovery.


Assuntos
Apoptose/efeitos dos fármacos , Proteínas de Bactérias/metabolismo , Cisteína Endopeptidases/metabolismo , Inibidores de Cisteína Proteinase/farmacologia , Dipeptídeos/farmacologia , Cetonas/farmacologia , Plasmodium falciparum/enzimologia , Amidas/química , Animais , Antimaláricos/química , Antimaláricos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Sobrevivência Celular/efeitos dos fármacos , Dipeptídeos/química , Descoberta de Drogas/métodos , Ácidos Graxos Insaturados/química , Feminino , Células Hep G2 , Humanos , Cetonas/química , Malária Falciparum/tratamento farmacológico , Malária Falciparum/parasitologia , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Estresse Oxidativo/efeitos dos fármacos
7.
Immunol Cell Biol ; 98(9): 757-769, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32623757

RESUMO

The immune blood cells "hemocytes" of mosquitoes impart a highly selective immune response against various microorganisms/pathogens. Among several immune effectors, fibrinogen-related proteins (FREPs) have been recognized as key modulators of cellular immune responses; however, their physiological relevance has not been investigated in detail. Our ongoing comparative RNA-sequencing analysis identified a total of 13 FREPs originating from naïve sugar-fed, blood-fed, bacterial challenged and Plasmodium vivax-infected hemocytes in Anopheles stephensi. Transcriptional profiling of the selected seven FREP transcripts showed distinct responses against different pathophysiological conditions, where an exclusive induction of FREP12 after 10 days of P. vivax infection was observed. This represents a possible role of FREP12 in immunity against free circulating sporozoites and needs to be explored in the future. When challenged with live bacterial injection in the thorax, we observed a higher affinity of FREP13 and FREP65 toward Gram-negative and Gram-positive bacteria in the mosquito hemocytes, respectively. Furthermore, we observed increased bacterial survival and proliferation, which is likely compromised by the downregulation of TEP1, in FREP13 messenger RNA-depleted mosquito hemolymph. In contrast, after blood-feeding, we also noticed a significant delay of 24 h in the enrichment of gut endosymbionts in the FREP13-silenced mosquitoes. Taken together, we conclude that hemocyte-specific FREP13 carries the unique ability of tissue-specific regulation, having an antagonistic antibacterial role in the hemolymph, and an agonistic role against gut endosymbionts.


Assuntos
Anopheles , Microbioma Gastrointestinal , Hemócitos/parasitologia , Hemolinfa/microbiologia , Proteínas de Insetos/genética , Animais , Anopheles/imunologia , Bactérias , Plasmodium vivax , Esporozoítos , Simbiose
9.
BMC Pulm Med ; 20(1): 302, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33198714

RESUMO

BACKGROUND: The increasing trend of Chronic Obstructive Pulmonary Disease (COPD) in becoming the third leading cause of deaths by 2020 is of great concern, globally as well as in India. Dysregulation of protease/anti-protease balance in COPD has been reported to cause tissue destruction, inflammation and airway remodelling; which are peculiar characteristics of COPD. Therefore, it is imperative to explore various serum proteases involved in COPD pathogenesis, as candidate biomarkers. COPD and Asthma often have overlapping symptoms and therefore involvement of certain proteases in their pathogenesis would render accurate diagnosis of COPD to be difficult. METHODS: Serum samples from controls, COPD and Asthma patients were collected after requisite institutional ethics committee approvals. The preliminary analysis qualitatively and quantitatively analyzed various serum proteases by ELISA and mass spectrometry techniques. In order to identify a distinct biomarker of COPD, serum neutrophil elastase (NE) and matrix metalloprotease-2 (MMP-2) from COPD and Asthma patients were compared; as these proteases tend to have overlapping activities in both the diseases. A quantitative analysis of the reactive oxygen species (ROS) in the serum of controls and COPD patients was also performed. Statistical analysis for estimation of p-values was performed using unpaired t-test with 95% confidence interval. RESULTS: Amongst the significantly elevated proteases in COPD patients vs the controls- neutrophil elastase (NE) [P < 0.0241], caspase-7 [P < 0.0001] and matrix metalloprotease-2 (MMP-2) [P < 0.0001] were observed, along with increased levels of reactive oxygen species (ROS) [P < 0.0001]. The serum dipeptidyl peptidase-IV (DPP-IV) [P < 0.0010) concentration was found to be decreased in COPD patients as compared to controls. Interestingly, a distinct elevation of MMP-2 was observed only in COPD patients, but not in Asthma, as compared to controls. Mass spectrometry analysis further identified significant alterations (fold-change) in various proteases (carboxy peptidase, MMP-2 and human leukocyte elastase), anti-proteases (Preg. zone protein, α-2 macroglobulin, peptidase inhibitor) and signalling mediators (cytokine suppressor- SOCS-3). CONCLUSION: The preliminary study of various serum proteases in stable COPD patients distinctly identified elevated MMP-2 as a candidate biomarker for COPD, subject to its validation in large cohort studies.


Assuntos
Elastase de Leucócito/sangue , Metaloproteinase 2 da Matriz/sangue , Doença Pulmonar Obstrutiva Crônica/sangue , Espécies Reativas de Oxigênio/sangue , Biomarcadores/sangue , Humanos , Índia , Doença Pulmonar Obstrutiva Crônica/patologia , Índice de Gravidade de Doença
10.
Exp Parasitol ; 197: 43-50, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30648557

RESUMO

Falcipain-2 (FP2) and falcipain-3 (FP3) constitute the major hemoglobinases of Plasmodium falciparum. Previous biochemical and structural studies have explained the mechanism of inhibition of these enzymes by small molecules. However, a residue-level protein-protein interaction (PPI) with its natural macromolecular substrate, hemoglobin is not fully characterized. Earlier studies have identified a short motif in the C-terminal of FP2, an exosite protruding away from the active site, essential for hemoglobin degradation. Our structural and mutagenesis studies suggest that hemoglobin interacts with FP2 via specific interactions mediated by Glu185 and Val187 within the C-terminal motif, which are essential for hemoglobin binding. Since FP3 is also a major hemoglobinase and essential for parasite survival, we further demonstrate its interactions with hemoglobin. Our results suggest that Asp194 of FP3 is required for hemoglobin hydrolysis and residue-swap experiments confirmed that this position is functionally conserved between the two hemoglobinases. Residues involved in protein-protein interactions constitute important targets for drug-mediated inhibition. Targeting protein-protein interactions at exosites may likely be less susceptible to emergence of drug resistance and thus is a new field to explore in malaria.


Assuntos
Cisteína Endopeptidases/metabolismo , Hemoglobinas/metabolismo , Plasmodium falciparum/enzimologia , Ácido Aspártico/química , Clonagem Molecular , Cisteína Endopeptidases/química , Cisteína Endopeptidases/genética , Ácido Glutâmico/química , Hemoglobinas/química , Hidrólise , Estrutura Molecular , Mutagênese , Plasmodium falciparum/genética
11.
Parasitol Res ; 118(1): 29-42, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30478733

RESUMO

Despite several setbacks in the fight against malaria such as insecticide and drug resistance as well as low efficacy of available vaccines, considerable success in reducing malaria burden has been achieved in the past decade. Artemisinins (ARTs and their combination therapies, ACTs), the current frontline drugs against uncomplicated malaria, rapidly kill plasmodial parasites and are non-toxic at short exposures. Though the exact mode of action remains unclear, the endoperoxide bridge, indispensable for ART activity, is thought to react with heme released from hemoglobin hydrolysis and generate free radicals that alkylate multiple protein targets, thereby disrupting proteostasis pathways. However, rapid development of ART resistance in recent years with no potential alternatives on the horizon threaten the elimination efforts. The Greater Mekong Subregion in South-East Asia continues to churn out mutants resistant to multiple ACTs and detected in increasingly expanding geographies. Extensive research on ART-resistant strains have identified a potential candidate Kelch13, crucial for mediating ART resistance. Parasites with mutations in the propeller domains of Plasmodium falciparum Kelch13 protein were shown to have enhanced phosphatidylinositol 3-kinase levels that were concomitant with delayed parasite clearance. Current research focused on understanding the mechanism of Kelch13-mediated ART resistance could provide better insights into Plasmodium resistome. This review covers the current proposed mechanisms of ART activity, resistance strategies adopted by the parasite in response to ACTs and possible future approaches to mitigate the spread of resistance from South-East Asia.


Assuntos
Antimaláricos/farmacologia , Artemisininas/farmacologia , Resistência a Medicamentos/genética , Malária/tratamento farmacológico , Plasmodium/efeitos dos fármacos , Antimaláricos/química , Artemisininas/química , Sudeste Asiático/epidemiologia , Humanos , Malária/epidemiologia , Malária/parasitologia , Modelos Moleculares , Mutação , Plasmodium/genética , Domínios Proteicos
12.
Parasitol Res ; 118(1): 385, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30552575

RESUMO

Author Atul Yadav would like to present his name as Atul only to be the same with his previous publications. The original article has been corrected.

13.
Biochemistry ; 56(3): 534-542, 2017 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-27478903

RESUMO

Charged, solvent-exposed residues at the entrance to the substrate binding site (gatekeeper residues) produce electrostatic dipole interactions with approaching substrates, and control their access by a novel mechanism called "electrostatic gatekeeper effect". This proof-of-concept study demonstrates that the nucleotide specificity can be engineered by altering the electrostatic properties of the gatekeeper residues outside the binding site. Using Blastocystis succinyl-CoA synthetase (SCS, EC 6.2.1.5), we demonstrated that the gatekeeper mutant (ED) resulted in ATP-specific SCS to show high GTP specificity. Moreover, nucleotide binding site mutant (LF) had no effect on GTP specificity and remained ATP-specific. However, via combination of the gatekeeper mutant with the nucleotide binding site mutant (ED+LF), a complete reversal of nucleotide specificity was obtained with GTP, but no detectable activity was obtained with ATP. This striking result of the combined mutant (ED+LF) was due to two changes; negatively charged gatekeeper residues (ED) favored GTP access, and nucleotide binding site residues (LF) altered ATP binding, which was consistent with the hypothesis of the "electrostatic gatekeeper effect". These results were further supported by molecular modeling and simulation studies. Hence, it is imperative to extend the strategy of the gatekeeper effect in a different range of crucial enzymes (synthetases, kinases, and transferases) to engineer substrate specificity for various industrial applications and substrate-based drug design.


Assuntos
Trifosfato de Adenosina/química , Blastocystis/genética , Guanosina Trifosfato/química , Engenharia de Proteínas , Proteínas de Protozoários/química , Succinato-CoA Ligases/química , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Blastocystis/enzimologia , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Guanosina Trifosfato/metabolismo , Cinética , Simulação de Dinâmica Molecular , Mutação , Ligação Proteica , Estrutura Secundária de Proteína , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Eletricidade Estática , Especificidade por Substrato , Succinato-CoA Ligases/genética , Succinato-CoA Ligases/metabolismo , Suínos
14.
Bioorg Med Chem ; 23(8): 1817-27, 2015 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-25766631

RESUMO

Phthalimides functionalized with cyclic amines were synthesized, characterized and screened for their in vitro antimalarial efficacy against Plasmodium falciparum (Pf3D7). Of all the listed phthalimides evaluated, 14 and 24 were identified as potent antimalarial agents as advocated by assessment of their ability to inhibit [(3)H] hypoxanthine incorporation in the nucleic acid of parasites. In addition, phthalimides 14 and 24 were incubated for 60 and 90h and an enhanced antimalarial effect was noticed with increase in time to great extent. A reduction in IC50 values was observed with increase in exposure time of the parasite to the compounds. A symmetric phthalimide, 24 possessing piperazine as linker unit was identified as the most potent antimalarial agent with IC50 values of 5.97±0.78, 2.0±1.09 and 1.1±0.75µM on incubation period of 42, 60 and 90h, respectively. The abnormal morphologies such as delay in developmental stages, growth arrest and condensed nuclei of parasite were observed with the aid of microscopic studies upon exposure with 14 and 24. The evaluation of 14 and 24 against chloroquine resistant strain, (Pf7GB) of P. falciparum afforded IC50 values, 13.29±1.20 and 7.21±0.98µM, respectively. The combination of 24 with artemisinin (ART) showed enhanced killing of parasite against Pf3D7. Further, all phthalimides were evaluated for their activity against falcipain-2 (FP2), a major hemoglobinase of malarial parasite. The enzymatic assay afforded 6 as most active member against FP2. To the best of our knowledge this is the initial study represents phthalimide protected amino acids functionalized with cyclic amines as potent antimalarial agents.


Assuntos
Antimaláricos/química , Antimaláricos/farmacologia , Cisteína Endopeptidases/metabolismo , Ftalimidas/química , Ftalimidas/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Antimaláricos/síntese química , Humanos , Malária Falciparum/tratamento farmacológico , Malária Falciparum/microbiologia , Simulação de Acoplamento Molecular , Ftalimidas/síntese química , Piperazinas/síntese química , Piperazinas/química , Piperazinas/farmacologia , Plasmodium falciparum/metabolismo
15.
Parasite Epidemiol Control ; 26: e00362, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38975253

RESUMO

Malaria is still a public health problem in tropical countries like India; major malaria parasite species are Plasmodium falciparum and P. vivax. Of which, P. vivax is responsible for ∼40% of the malaria burden at least in the Indian scenario. Unfortunately, there is limited data on the population structure and genetic diversity of P. vivax parasites in India. In this study, we investigated the genetic diversity of P. vivax strains in the South-west district, Delhi and, Nuh district, Haryana [National Capital Region (NCR)], using a polymorphic marker- P. vivax merozoite surface protein-3α (PvMSP-3α) gene. Dried blood spots from microscopically confirmed P. vivax patients were used for investigation of the PvMSP-3α gene. PCR-RFLP was performed on the PvMSP-3α gene to investigate the genotypes and allelic variability with HhaI and AluI restriction enzymes. In total, 40 successfully PCR amplified PvMSP-3α gene segments were subjected to RFLP analysis. Amplified products showed three different base pair size variations viz. genotype A in 31(77.5%), genotype B in 4(10%) and genotype C in 5(12.5%) P. vivax specimens. RFLP with HhaI and AluI revealed 17 (H1-H17) and 25 (A1-A25) allelic variants, respectively. Interestingly, two similar sub-allelic variants, ie. H8 (with HhaI), and A4 (with AluI) clustered within the rural area of Nuh district, Haryana in two samples. With this study, we propose to commission such type of genetic diversity analysis of P. vivax to investigate the circulating genotypes of the parasites from distinct geographical locations across India, that can have significant implications in understanding the population structures of P. vivax.

16.
RSC Adv ; 14(2): 1114-1122, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38174259

RESUMO

In recent days, biogenic and green approaches for synthesizing nanostructures have gained much attention in biological and biomedical applications. Endophytic fungi have been recognized to produce several important biomolecules for use in various fields. The present work describes the use of endophytic fungi isolated from Berberis aristata for the synthesis of multi-twinned silver nanoparticles (MT-AgNPs) and their successful applications in antimicrobial and antimalarial studies. TEM images reveal the formation of multi-twined structures in the synthesized silver nanoparticles. The synthesized MT-AgNPs have shown excellent antibacterial activities against five opportunistic bacteria, viz. Bacillus subtilis (MTCC 441), Pseudomonas aeruginosa (MTCC 424), Escherichia coli (MTCC 443), Klebsiella pneumonia (MTCC 3384), and Aeromonas salmonicida (MTCC 1522). The synthesized MT-AgNPs also exhibit interesting antimalarial activities against Plasmodium falciparum parasites (3D7 strain) by displaying 100% inhibition at a concentration of 1 µg mL-1 against the malaria parasite P. falciparum 3D7. Overall, the results describe a green method for the production of twinned-structured nanoparticles and their potential to be applied in the biomedical, pharmaceutical, food preservation, and packaging industries.

17.
Int J Biol Macromol ; 265(Pt 1): 130420, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38460641

RESUMO

Proteolytic activity constitutes a fundamental process essential for the survival of the malaria parasite and is thus highly regulated. Falstatin, a protease inhibitor of Plasmodium falciparum, tightly regulates the activity of cysteine hemoglobinases, falcipain-2 and 3 (FP2, FP3), by inhibiting FP2 through a single surface exposed loop. However, the multimeric nature of falstatin and its interaction with FP2 remained unexplored. Here we report that the N-terminal falstatin region is highly disordered, and needs chaperone activity (heat-shock protein 70, HSP70) for its folding. Protein-protein interaction assays showed a significant interaction between falstatin and HSP70. Further, characterization of the falstatin multimer through a series of biophysical techniques identified the formation of a falstatin decamer, which was extremely thermostable. Computational analysis of the falstatin decamer showed the presence of five falstatin dimers, with each dimer aligned in a head-to-tail orientation. Further, the falstatin C-terminal region was revealed to be primarily involved in the oligomerization process. Stoichiometric analysis of the FP2-falstatin multimer showed the formation of a heterooligomeric complex in a 1:1 ratio, with the participation of ten subunits of each protein. Taken together, our results report a novel protease-inhibitor complex and strengthens our understanding of the regulatory mechanisms of major plasmodium hemoglobinases.


Assuntos
Cisteína Endopeptidases , Plasmodium falciparum , Dobramento de Proteína
18.
Bioorg Med Chem ; 21(17): 5503-9, 2013 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-23810423

RESUMO

Self-assembled peptide based nanostructures gained enough popularity due to their easy biocompatibility and numerous potential applications. An excellent model of self-assembly of hydroxyethylamine based peptide nanostructures was synthesized and characterized by DLS and TEM. Spherical nano structures of I and III were observed with particle size ∼50 and ∼80nm, respectively. Further, I and III were screened against anti-malarial target, falcipain-3 (FP3), a crucial cysteine protease involved as a major hemoglobinase of Plasmodium falciparum. Interestingly, compound III completely inhibited the activity of FP3. The effective concentration (1.5µM) of III found to be more potent than I. This biochemical result was substantiated by molecular-docking studies indicating III to be best inhibitor of FP3. This is the first report showing that bis hydroxethylamine based peptide nanostructures could be very effective inhibitor of malarial cysteine proteases.


Assuntos
Aminas/química , Antimaláricos/química , Cisteína Endopeptidases/química , Nanoestruturas/química , Peptídeos/química , Plasmodium falciparum/enzimologia , Inibidores de Proteases/química , Inibidores de Proteases/síntese química , Antimaláricos/síntese química , Antimaláricos/farmacologia , Sítios de Ligação , Domínio Catalítico , Cisteína Endopeptidases/metabolismo , Ligantes , Simulação de Acoplamento Molecular , Tamanho da Partícula , Peptídeos/síntese química , Peptídeos/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Inibidores de Proteases/farmacologia
19.
Front Vet Sci ; 10: 1127273, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36777671

RESUMO

Introduction: The imminent risk of zoonoses of non-human malaria parasites is not far from reality in India, as has been observed in the case of Plasmodium knowlesi (Pk), and so is possible with P. cynomolgi (Pc), already reported from South East Asian countries. Therefore, a novel multiplex qPCR assay was developed and evaluated for detection of non-human malaria parasites- Pk and Pc in populations at risk. Methods: The qPCR primers were designed in-house with fluorescence labeled probes (HEX for Pk and FAM for Pc). DNA samples of Pk and Pc were used as templates and further the qPCR assay was evaluated in 250 symptomatic and asymptomatic suspected human blood samples from malaria endemic areas of North Eastern states of India. Results: The qPCR assay successfully amplified the target 18S rRNA gene segment from Pk and Pc and was highly specific for Pk and Pc parasites only, as no cross reactivity was observed with P. falciparum (Pf), P. vivax (Pv), P. malariae (Pm), and P. ovale (Po). Standard curves were generated to estimate the limit of detection (LOD) of Pk and Pc parasites DNA (0.00275 & 0.075 ng/µl, respectively). Due to COVID-19 pandemic situation during 2020-21, the sample accessibility was difficult, however, we managed to collect 250 samples. The samples were tested for Pf and Pv using conventional PCR- 14 Pf and 11 Pv infections were observed, but no Pk and Pc infections were detected. For Pk infections, previously reported conventional PCR was also performed, but no Pk infection was detected. Discussion: The multiplex qPCR assay was observed to be robust, quick, cost-effective and highly sensitive as compared to the currently available conventional PCR methods. Further validation of the multiplex qPCR assay in field setting is desirable, especially from the high-risk populations. We anticipate that the multiplex qPCR assay would prove to be a useful tool in mass screening and surveillance programs for detection of non-human malaria parasites toward the control and elimination of malaria from India by 2030.

20.
PLoS One ; 18(3): e0282580, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36920996

RESUMO

Nipah virus (NiV) is an emerging zoonotic virus that caused several serious outbreaks in the south asian region with high mortality rates ranging from 40 to 90% since 2001. NiV infection causes lethal encephalitis and respiratory disease with the symptom of endothelial cell-cell fusion. No specific and effective vaccine has yet been reported against NiV. To address the urgent need for a specific and effective vaccine against NiV infection, in the present study, we have designed two Multi-Epitope Vaccines (MEVs) composed of 33 Cytotoxic T lymphocyte (CTL) epitopes and 38 Helper T lymphocyte (HTL) epitopes. Out of those CTL and HTL combined 71 epitopes, 61 novel epitopes targeting nine different NiV proteins were not used before for vaccine design. Codon optimization for the cDNA of both the designed MEVs might ensure high expression potential in the human cell line as stable proteins. Both MEVs carry potential B cell linear epitope overlapping regions, B cell discontinuous epitopes as well as IFN-γ inducing epitopes. Additional criteria such as sequence consensus amongst CTL, HTL and B Cell epitopes was implemented for the design of final constructs constituting MEVs. Hence, the designed MEVs carry the potential to elicit cell-mediated as well as humoral immune response. Selected overlapping CTL and HTL epitopes were validated for their stable molecular interactions with HLA class I and II alleles and in case of CTL epitopes with human Transporter Associated with antigen Processing (TAP) cavity. The structure based epitope cross validation for interaction with TAP cavity was used as another criteria choosing final epitopes for NiV MEVs. Finally, human Beta-defensin 2 and Beta-defensin 3 were used as adjuvants to enhance the immune response of both the MEVs. Molecular dynamics simulation studies of MEVs-TLR3 ectodomain (Human Toll-Like Receptor 3) complex indicated the stable molecular interaction. We conclude that the MEVs designed and in silico validated here could be highly potential vaccine candidates to combat NiV infections, with great effectiveness, high specificity and large human population coverage worldwide.


Assuntos
Infecções por Henipavirus , Vacinas Virais , beta-Defensinas , Humanos , Biologia Computacional , Epitopos de Linfócito B , Epitopos de Linfócito T , Simulação de Acoplamento Molecular , Receptor 3 Toll-Like , Vacinas de Subunidades Antigênicas , Antígenos HLA/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA