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1.
Acta Trop ; 241: 106867, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36878386

RESUMO

Visceral leishmaniasis is neglected tropical protozoan disease caused by Leishmania donovani and are associated with high fatality rate in developing countries since prophylactic vaccines are not available. In the present study, we evaluated the immunomodulatory potential of L. donovani histidyl-tRNA synthetase (LdHisRS) and predicted the epitopes using immunoinformatic tools. Histidyl-tRNA synthetase (HisRS) is a class IIa aminoacyl t-RNA synthetase enzyme (aaRS) required for histidine incorporation into proteins during protein synthesis. The recombinant LdHisRS protein (rLdHisRS) was expressed in E coli BL-21cells, and its immunomodulatory role was assessed in J774A.1 murine macrophage and in BALB/c mice, respectively. LdHisRS specifically stimulated and triggered enhance cell proliferation, nitric oxide release and IFN-γ (70%; P < 0.001), and IL-12 (55.37%; P < 0.05) cytokine release in vitro, whereas BALB/c mice immunized with rLdHisRS show higher NO release (80.95%; P<0.001), higher levels of Th1 cytokines IFN-γ (14%; P < 0.05), TNF-α (34.93%; P < 0.001), and IL-12 (28.49%; P < 0.001) and robust IgG (p<0.001) and IgG2a (p<0.001) production. We also identified 20 Helper T-lymphocytes (HTLs), 30 cytotoxic T lymphocytes (CTLs), and 18 B-cell epitopes from HisRS protein of L. donovani. All these epitopes can be further used to make a multiepitope vaccine against L. donovani.


Assuntos
Leishmania donovani , Vacinas contra Leishmaniose , Leishmaniose Visceral , Vacinas , Animais , Camundongos , Leishmania donovani/genética , Leishmaniose Visceral/prevenção & controle , Histidina-tRNA Ligase , Escherichia coli , Células Th1 , Citocinas , Interleucina-12 , Proteínas Recombinantes/genética , Epitopos , Camundongos Endogâmicos BALB C , Proteínas de Protozoários/genética , Antígenos de Protozoários/genética
2.
Mol Divers ; 27(1): 323-340, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35467269

RESUMO

Cervical cancer is a major cause of gynecological related mortalities in developing countries. Cisplatin, a potent chemotherapeutic agent used for treating advanced cervical cancer exhibits side effects and resistance development. The current study was aimed to investigate the repurposing of l-menthol as a potential therapeutic drug against cervical cancer. L-menthol was predicted to be non-toxic with good pharmacokinetic properties based on SwissADME and pkCSM analysis. Subsequently, 543 and 1664 targets of l-menthol and cervical cancer were identified using STITCH, BATMAN-TCM, PharmMapper and CTD databases. STRING and Cytoscape analysis of the merged protein-protein interaction network revealed 107 core targets of l- menthol against cervical cancer. M-CODE identified highly connected clusters between the core targets which through KEGG analysis were found to be enriched in pathways related to apoptosis and adherence junctions. Molecular docking showed that l- menthol targeted E6, E6AP and E7 onco-proteins of HPV that interact and inactivate TP53 and Rb1 in cervical cancer, respectively. Molecular docking also showed good binding affinity of l-menthol toward proteins associated with apoptosis and migration. Molecular dynamics simulation confirmed stability of the docked complexes. In vitro analysis confirmed that l-menthol was cytotoxic towards cervical cancer CaSki cells and altered expression of TP53, Rb1, CDKN1A, E2F1, NFKB1, Akt-1, caspase-3, CDH1 and MMP-2 genes identified through network pharmacology approach. Schematic representation of the work flow depicting the potential of l-menthol to target cervical cancer.


Assuntos
Mentol , Neoplasias do Colo do Útero , Feminino , Humanos , Mentol/farmacologia , Simulação de Acoplamento Molecular , Farmacologia em Rede , Neoplasias do Colo do Útero/tratamento farmacológico
3.
Toxicol In Vitro ; 86: 105512, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36336213

RESUMO

Plumbagin is a natural compound known to impede growth of cancerous cells. However, anti-cervical cancer effects of plumbagin and its underlying molecular mechanism still remains elusive. In this study, plumbagin reduced the viability of CaSki cells in a concentration dependent manner and suppressed their colony formation potential. It led to G2/M phase arrest with downregulation of E2F1 and upregulation of p21. Plumbagin reduced mitochondrial membrane potential and concomitantly increased the percentage of apoptotic cells as revealed by annexin V-propidium iodide staining. Real Time PCR and western blotting confirmed that plumbagin induced apoptosis by reducing the expression of pAkt, procaspase 9 and full-length PARP. Furthermore, scratch assay showed that plumbagin suppressed migratory potential of CaSki cells which could be due to the reduced expression and activity of MMP-2 and upregulation of TIMP2. Interestingly, plumbagin also downregulated UHRF1 expression. Transient silencing of UHRF1 like plumbagin, induced G2/M phase arrest, enhanced apoptosis and suppressed metastasis of CaSki cells suggesting the role of UHRF1 in mediating anti-cancer activities of plumbagin. Plumbagin at IC20 (1 µM) interacted synergistically with cisplatin and reduced its IC50 value by 13.23 fold with improved effectivity as revealed by augmented apoptosis in CaSki cells.


Assuntos
Naftoquinonas , Neoplasias do Colo do Útero , Feminino , Humanos , Apoptose , Proteínas Estimuladoras de Ligação a CCAAT , Linhagem Celular Tumoral , Proliferação de Células , Metaloproteinase 2 da Matriz/genética , Naftoquinonas/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ubiquitina-Proteína Ligases , Neoplasias do Colo do Útero/tratamento farmacológico
4.
Biochem Biophys Res Commun ; 626: 107-113, 2022 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-35987095

RESUMO

Acinetobacter baumannii is an opportunistic pathogen known for high morbidity and mortality. It causes life-threatening infections, such as ventilator-associated pneumonia (VAP), bacteremia, meningitis, wound and urinary tract infections (UTI). Increase in carbapenem resistance exhibited by A. baumannii has accentuated the need for novel targets for effective treatment. Despite the pronounced relevance of PPK2 as a pathogenicity determinant in several pathogens, it has not been explored as a drug target in A. baumannii. The present study was piloted to investigate the substrate binding by A. baumannii PPK2 (AbPPK2), a two-domain Class II polyphosphate kinase 2. A homology model of AbPPK2 was developed and validated for molecular docking of ATP and ADP in the predicted binding pocket. Further analysis of AbPPK2 revealed a set of common residues in the catalytic cleft interacting with ATP and ADP which would be useful for the screening of inhibitors against A. baumannii.


Assuntos
Acinetobacter baumannii , Difosfato de Adenosina/farmacologia , Monofosfato de Adenosina/farmacologia , Trifosfato de Adenosina/farmacologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Simulação de Acoplamento Molecular , Polifosfatos/metabolismo
5.
Arch Microbiol ; 204(9): 562, 2022 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-35980477

RESUMO

Statistical optimization of aeration conditions viz. aerobic, microaerobic and anaerobic, was performed using response surface methodology (RSM) utilizing soybean meal as medium to enhance the production of laccase from Rheinheimera sp. Maximum laccase yield (18.48 × 105 U/L) was obtained under microaerobic (static) conditions sustained for 12 h in tandem with 26 h aerobically (150 rpm) grown culture, which was 17.03-fold higher than laccase production in the starting M162 medium under aerobic conditions (150 rpm). The reduction in incubation time from 72 to 38 h and utilization of cost-effective soybean meal as medium, which is easily available from local market, have provided a promising, eco-friendly method of laccase enzyme production. Enhanced expression of laccase gene under microaerobic conditions corresponded to the increased expression of fnr (fumarate nitrate reductase) gene, the oxygen sensing global regulator. The putative FNR-binding site upstream of laccase transcription initiation site was predicted to play an imperative role in Rheinheimera sp. adaptation from aerobic to microaerobic conditions and for enhanced laccase production.


Assuntos
Chromatiaceae , Lacase , Lacase/genética , Lacase/metabolismo , Nitrato Redutase , Nitratos , Oxigênio
6.
Mol Biochem Parasitol ; 251: 111510, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35988745

RESUMO

TriTryp diseases (Leishmaniasis, Human African Trypanosomiasis (HAT), and Chagas disease) are devastating parasitic neglected tropical diseases (NTDs) that affect billions of people in developing countries, cause high mortality in humans, and impose a large socio-economic burden. The current treatment options against tritryp diseases are suboptimal and challenging due to the emergence of resistance against available tritryp drugs. Hence, designing and developing effective anti-tritryp drugs with novel targets are required. Aminoacyl-tRNA synthetases (AARSs) involved in specific aminoacylation of transfer RNAs (tRNAs), interrupt protein synthesis through inhibitors, and retard the parasite growth. AaRSs have long been studied as therapeutic targets in bacteria, and three aaRS inhibitors, mupirocin (against IleRS), tavaborole AN2690 (against LeuRS), and halofuginone (against ProRS), are already in clinical practice. The structural differences between tritryp and human aaRSs and the presence of unique sequences (N-terminal domain/C-terminal domain/catalytic domain) make them potential target for developing selective inhibitors. Drugs based on a single aaRS target developed by high-throughput screening (HTS) are less effective due to the emergence of resistance. However, designing multi-targeted drugs may be a better strategy for resistance development. In this perspective, we discuss the characteristics of tritryp aaRSs, sequence conservation in their orthologs and their peculiarities, recent advancements towards the single-target and multi-target aaRS inhibitors developed through rational design.


Assuntos
Aminoacil-tRNA Sintetases , Doença de Chagas , Leishmaniose , Tripanossomíase Africana , Aminoacil-tRNA Sintetases/química , Aminoacil-tRNA Sintetases/genética , Aminoacil-tRNA Sintetases/metabolismo , Aminoacilação , Animais , Humanos , Leishmaniose/tratamento farmacológico , Doenças Negligenciadas/tratamento farmacológico , Tripanossomíase Africana/tratamento farmacológico
7.
Pathog Dis ; 80(1)2022 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-35867872

RESUMO

Acinetobacter baumannii poses a global danger due to its ability to resist most of the currently available antimicrobial agents. Furthermore, the rise of carbapenem-resistant A. baumannii isolates has limited the treatment options available. In the present study, plant auxin 3-indoleacetonitrile (3IAN) was found to inhibit biofilm formation and motility of A. baumannii at sublethal concentration. Mechanistically, 3IAN inhibited the synthesis of the quorum sensing signal 3-OH-C12-HSL by downregulating the expression of the abaI autoinducer synthase gene. 3IAN was found to reduce the minimum inhibitory concentration of A. baumannii ATCC 17978 against imipenem, ofloxacin, ciprofloxacin, tobramycin, and levofloxacin, and significantly decreased persistence against imipenem. Inhibition of efflux pumps by downregulating genes expression may be responsible for enhanced sensitivity and low persistence. 3IAN reduced the resistance to imipenem in carbapenem-resistant A. baumannii isolates by downregulating the expression of OXA ß-lactamases (blaoxa-51 and blaoxa-23), outer membrane protein carO, and transporter protein adeB. These findings demonstrate the therapeutic potential of 3IAN, which could be explored as an adjuvant with antibiotics for controlling A. baumannii infections.


Assuntos
Acetonitrilas/farmacologia , Infecções por Acinetobacter , Acinetobacter baumannii , Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/genética , Antibacterianos/uso terapêutico , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes , Carbapenêmicos/metabolismo , Carbapenêmicos/farmacologia , Carbapenêmicos/uso terapêutico , Humanos , Imipenem/farmacologia , Testes de Sensibilidade Microbiana , beta-Lactamases/genética , beta-Lactamases/metabolismo
8.
Foods ; 11(10)2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35626980

RESUMO

In this study, we investigated the impact of harvest maturity stages and contrasting growing climates on secondary metabolites in Kinnow mandarin. Fruit samples were harvested at six harvest maturity stages (M1−M6) from two distinct growing locations falling under subtropical−arid (STA) and subtropical−humid (STH) climates. A high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) technique was employed to identify and quantify secondary metabolites in the fruit juice. A total of 31 polyphenolics and 4 limonoids, with significant differences (p < 0.05) in their concentration, were determined. With advancing maturity, phenolic acids and antioxidant activity were found to increase, whereas flavonoids and limonoids decreased in concentration. There was a transient increase in the concentration of some polyphenolics such as hesperidin, naringin, narirutin, naringenin, neoeriocitrin, rutin, nobiletin and tangeretin, and limonoid aglycones such as limonin and nomilin at mid-maturity stage (M3) which coincided with prevailing low temperature and frost events at growing locations. A higher concentration of limonin and polyphenolics was observed for fruit grown under STH climates in comparison to those grown under STA climates. The data indicate that fruit metabolism during advanced stages of maturation under distinct climatic conditions is fundamental to the flavor, nutrition and processing quality of Kinnow mandarin. This information can help in understanding the optimum maturity stage and preferable climate to source fruits with maximum functional compounds, less bitterness and high consumer acceptability.

9.
3 Biotech ; 12(3): 85, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35261870

RESUMO

Acinetobacter baumannii has emerged as one of major nosocomial pathogen and global emergence of multidrug-resistant strains has become a challenge for developing effective treatment options. A. baumannii has developed resistance to almost all the antibiotics viz. beta-lactams, carbapenems, tigecycline and now colistin, a last resort of antibiotics. The world is on the cusp of post antibiotic era and the evolution of multi-, extreme- and pan-drug-resistant A. baumannii strains is its obvious harbinger. Various combinations of antibiotics have been investigated but no successful treatment option is available. All these failed efforts have led researchers to develop and implement prophylactic vaccination for the prevention of infections caused by this pathogen. In this review, the advantages and disadvantages of active and passive immunization, the types of sub-unit and multi-component vaccine candidates investigated against A. baumannii viz. whole cell organism, outer membrane vesicles, outer membrane complexes, conjugate vaccines and sub-unit vaccines have been discussed. In addition, the benefits of Reverse vaccinology are emphasized here in which the potential vaccine candidates are predicted using bioinformatic online tools prior to in vivo validations.

10.
Curr Microbiol ; 79(3): 88, 2022 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-35129693

RESUMO

Acinetobacter baumannii is a multidrug-resistant bacteria responsible for nosocomial infections with significant fatality rates globally. Therapeutic failure and relapse of infection has been associated with persister cells formation which can also lead to resistance in A. baumannii. In the present study, we observed that A. baumannii ATCC 17978 in exponential phase survived lethal concentrations of amikacin, rifampicin and ciprofloxacin by generating persister cells but was unable to survive tobramycin treatment. The transcriptome of A. baumannii ATCC 17978 was analyzed following exposure to a high concentration of tobramycin (10 × MIC) for a short period of time to study the possible mechanisms responsible for lethality. Tobramycin reduced the expression of genes involved in energy production (nuoH, nuoN, nuoM, cydA, sucC), oxidative stress protection (tauD, cysD), and nutrition uptake (ompW) significantly. In addition, hemerythrin (non-heme di-iron oxygen-binding protein) was found to be the most downregulated gene in response to tobramycin which needs to be further studied for its role in susceptibility to antibiotics. Tobramycin upregulated the expression of genes that are mainly involved in stress response (leucine catabolism, DNA repair and HicAB toxin-antitoxin system). The differentially expressed genes highlighted in the study provided insight into the probable molecular mechanism of tobramycin-induced cell death and revealed some novel targets that can be explored further for their potential to control A. baumannii.


Assuntos
Acinetobacter baumannii , Acinetobacter baumannii/genética , Amicacina , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana Múltipla , Expressão Gênica , Testes de Sensibilidade Microbiana , Tobramicina/farmacologia
11.
Bioresour Technol ; 347: 126706, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35033642

RESUMO

Lignocellulosic biomass is a plentiful renewable resource that can be converted into a wide range of high-value-added industrial products. However, the complexity of its structural integrity is one of the major constraints and requires combinations of different fibrolytic enzymes for the cost-effective, industrially and environmentally feasible transformation. An interesting approach is constructing multifunctional enzymes, either in a single polypeptide or by joining multiple domains with linkers and performing diverse reactions simultaneously, in a single host. The production of such chimera proteins multiplies the advantages of different enzymatic reactions in a single setup, in lesser time, at lower production cost and with desirable and improved catalytic activities. This review embodies the various domain-tailoring and extracellular secretion strategies, possible solutions to their challenges, and efforts to experimentally connect different catalytic activities in a single host, as well as their applications.


Assuntos
Lignina , Enzimas Multifuncionais , Biomassa
12.
Environ Sci Pollut Res Int ; 29(3): 3355-3371, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34773239

RESUMO

The overuse of antibiotics and their disposal without processing are leading the environment and its inhabitants towards a serious health emergency. There is abundance of diverse antibiotic resistance genes and bacteria in environment, which demands immediate attention for the effective removal of antibiotics. There are physical and chemical methods for removal, but the generation of toxic byproducts has directed the efforts towards bioremediation for eco-friendly and sustainable elimination of antibiotics from the environment. Various effective and reliable bioremediation approaches have been used, but still antibiotic residues pose a major global threat. Recent developments in molecular and synthetic biology might offer better solution for engineering of microbe-metabolite biodevices and development of novel strains endowed with desirable properties. This review summarizes the impact of antibiotics on environment, mechanisms of resistance development, and different bioremediation approaches.


Assuntos
Antibacterianos , Farmacorresistência Bacteriana , Antibacterianos/farmacologia , Bactérias/genética , Biodegradação Ambiental
13.
Int J Biol Macromol ; 193(Pt B): 1835-1844, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34774862

RESUMO

COVID-19 pandemic continues to be a global threat, affecting more than 200 countries/territories at both human and economic level. This necessitates the rapid development of highly reliable diagnostic methods in order to effectively and accurately diagnose the pathology to prevent the spread of COVID-19. Currently, RT-PCR is the most widely used method worldwide for SARS-CoV-2 detection. Serological assays are being used for sero-surveys of SARS-CoV-2 antibody prevalence in the community. Radiology imaging has been useful in the clinical diagnosis of COVID-19. These methods have their own limitations and there are continued efforts to develop easier, economic, highly sensitive and specific, point-of-care methods. Reverse transcription-loop mediated isothermal amplification (RT-LAMP), nucleic acid sequence-based amplification (NASBA), CRISPR-Cas-based detection, and digital PCR are such techniques being employed in research laboratories, with many awaiting diagnostic approval from competent authorities. This review highlights the rapidly expanding array of existing and in-development diagnostic tests/strategies that may be used to diagnose SARS-CoV-2 infection in both clinical and research settings.


Assuntos
Teste de Ácido Nucleico para COVID-19 , COVID-19 , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico , Pandemias , Sistemas Automatizados de Assistência Junto ao Leito , RNA Viral/genética , SARS-CoV-2/genética , COVID-19/epidemiologia , COVID-19/genética , Humanos
14.
Life Sci ; 282: 119802, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34237314

RESUMO

AIM: To investigate the anti-cancer potential of salicylic acid and cisplatin combination in HeLa cells and the underlying mechanism. MAIN METHODS: Drugs and disease targets were extracted from DrugBank, BATMAN-TCM, STITCH, PharmMapper and Comparative Toxigenomics Database. Cytoscape 3.8.2 was used to merge the protein-protein interaction networks and select core targets. GO and KEGG analysis was done using Metascape and WebGestalt. Effect of salicylic acid and cisplatin alone and in combination on cells viability was studied by MTT assay. The type of interaction between salicylic acid and cisplatin was determined by CompuSyn. Apoptosis was evaluated by molecular docking, Rhodamine-123, DAPI, AO/EtBr staining, flow cytometry, qRT-PCR and western blotting. Metastasis was studied using scratch assay and western blotting. UHRF1 transient silencing was performed by siRNA. KEY FINDINGS: Out of 420, 1863 and 1362 respective targets of salicylic acid, cisplatin and cervical cancer, 18 core proteins were enriched in apoptosis and cell migration related pathways. IC50 value of cisplatin was reduced by 14 fold in combination with salicylic acid at IC20 (4 µM). There was loss of mitochondrial membrane potential and downregulation of UHRF1, pAkt, full length PARP and pro-caspase 3 expression. Transient silencing of UHRF1 also induced mitochondrial depolarization and apoptosis. The combination also exhibited anti-metastasis effect as it suppressed migration, upregulated PAX1 and downregulated MMP-2. SIGNIFICANCE: Reduction in cisplatin concentration, enhanced anti-cancer effects and UHRF1 downregulation due to synergistic interaction between salicylic acid and cisplatin underscores the therapeutic importance of the combination to overcome chemo-resistance and side effects of cisplatin.


Assuntos
Anti-Infecciosos/farmacologia , Antineoplásicos/farmacologia , Cisplatino/farmacologia , Ácido Salicílico/farmacologia , Apoptose/efeitos dos fármacos , Sinergismo Farmacológico , Feminino , Células HeLa , Humanos , Neoplasias do Colo do Útero/tratamento farmacológico
15.
Microbes Infect ; 23(9-10): 104844, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34098109

RESUMO

Acinetobacter baumannii is an opportunistic pathogen that has acquired resistance to all available drugs. The rise in multi-drug resistance in A. baumannii has been exacerbated by its ability to tolerate antibiotics due to the persister cells, which are phenotypic variants of normal cells that can survive various stress conditions, resulting in chronicity of infection. In the present study we observed that A. baumannii formed persister cells against lethal concentration of ciprofloxacin in exponential phase. The transcriptome of A. baumannii was analyzed after exposure to high concentration of ciprofloxacin (50X MIC) to determine the possible mechanisms of survival. Transcriptome analysis showed differential expression of 146 genes, of which 101 were up-regulated and 45 were down-regulated under ciprofloxacin stress. Differentially expressed genes that might be important for persistence against ciprofloxacin were involved in DNA repair, phenylacetic acid degradation, leucine catabolism, HicAB toxin-antitoxin system and ROS response (iron-sulfur clusters, hemerythrin-like metal binding and Kdp). recA, umuD and ddrR genes involved in SOS response were also up-regulated. Knockout of umuD showed significant decrease in persister cells formation while they were completely eradicated in recA mutant strain. The differentially expressed genes highlighted in the study merit further investigation as therapeutic targets for effective control of A. baumannii infections.


Assuntos
Acinetobacter baumannii , Antibacterianos/farmacologia , Ciprofloxacina/farmacologia , Testes de Sensibilidade Microbiana , Transcriptoma
16.
Microbes Infect ; 23(4-5): 104795, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33567337

RESUMO

Acinetobacter baumannii, a leading cause of nosocomial infections, is a serious health threat. Limited therapeutic options due to multi-drug resistance and tolerance due to persister cells have urged the scientific community to develop new strategies to combat infections caused by this pathogen effectively. Since combination antibiotic therapy is an attractive strategy, the effect of combinations of antibiotics, belonging to four classes, was investigated on eradication of persister cells in A. baumannii. Among the antibiotics included in the study, tobramycin-based combinations were found to be the most effective. Tobramycin, in combination with colistin or ciprofloxacin, eradicated persister cells in A. baumannii in late exponential and stationary phases of growth. Mechanistically, colistin facilitated the entry of tobramycin into cells by increasing membrane permeability and inducing hyperpolarization of the inner membrane accompanied by increase in ROS production. Expression of the genes encoding universal stress protein and efflux pumps was down-regulated in response to tobramycin and colistin, suggesting increased lethality of their combination that might be responsible for eradication of persister cells. Thus, a combination of tobramycin and colistin could be explored as a promising option for preventing the relapse of A. baumannii infections due to persister cells.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Colistina/farmacologia , Regulação para Baixo/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Tobramicina/farmacologia , Acinetobacter/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Ciprofloxacina/administração & dosagem , Ciprofloxacina/farmacologia , Colistina/administração & dosagem , Quimioterapia Combinada , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Permeabilidade/efeitos dos fármacos , Espécies Reativas de Oxigênio , Rifampina/administração & dosagem , Rifampina/farmacologia , Tobramicina/administração & dosagem
17.
Microbiol Res ; 242: 126627, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33131985

RESUMO

Acinetobacter baumannii is clinically one of the most significant pathogens, especially in intensive care settings, because of its multidrug-resistance (MDR). Repurposing of high-affinity drugs is a faster and more plausible approach for combating the emergence of MDR and to tackle bacterial infections. This study was aimed to evaluate the approved drugs potentially inhibiting A. baumannii PPK1 (AbPPK1) mediated synthesis of polyphosphates (polyP). Based on virtual screening, molecular dynamic simulation, and CD spectroscopy for thermal stability, two stable ligands, etoposide and genistein, were found with promising contours for further investigation. Following in vitro inhibition of AbPPK1, the efficacy of selected drugs was further tested against virulence traits of A. baumannii. These drugs significantly reduced the biofilm formation, surface motility in A. baumannii and led to decreased survival under desiccation. In addition to inhibition of PPK1, both drugs increased the expression of polyP degrading enzyme, exopolyphosphatase (PPX), that might be responsible for the decrease in the total cellular polyP. Since polyP modulates the virulence factors in bacteria, destabilization of the polyP pool by these drugs seems particularly striking for their therapeutic applications against A. baumannii.


Assuntos
Acinetobacter baumannii/enzimologia , Acinetobacter baumannii/metabolismo , Antibacterianos/farmacologia , Fosfotransferases (Aceptor do Grupo Fosfato)/efeitos dos fármacos , Fosfotransferases (Aceptor do Grupo Fosfato)/metabolismo , Fatores de Virulência/genética , Hidrolases Anidrido Ácido/metabolismo , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Acil-Butirolactonas/metabolismo , Biofilmes/crescimento & desenvolvimento , Clonagem Molecular , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Fosfotransferases (Aceptor do Grupo Fosfato)/química , Fosfotransferases (Aceptor do Grupo Fosfato)/genética , Polifosfatos/metabolismo , Análise de Sequência , Virulência/genética
18.
Appl Microbiol Biotechnol ; 104(10): 4457-4469, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32215705

RESUMO

Quorum sensing (QS) and signal molecules used for interspecies communication are well defined in mesophiles, but there is still a plethora of microorganisms in which existence and mechanisms of QS need to be explored, thermophiles being among them. In silico analysis has revealed the presence of autoinducer-2 (AI-2) class of QS signaling molecules in thermophiles, synthesized by LuxS (AI-2 synthase), though the functions of this system are not known. In this study, LuxS of Meiothermus ruber was used for understanding the mechanism and functions of AI-2 based QS among thermophilic bacteria. The luxS gene of M. ruber was expressed in luxS- deletion mutant of Escherichia coli. Complementation of luxS resulted in significant AI-2 activity, enhanced biofilm formation, and antibiotic susceptibility. Transcriptome analysis showed significant differential expression of 204 genes between the luxS-complemented and luxS- deletion mutant of E. coli. Majority of the genes regulated by luxS belonged to efflux pumps. This elucidation may contribute towards finding novel alternatives against incessant antibiotic resistance in bacteria.Key Points• Expression of luxS in luxS-E. coli resulted in increase in biofilm index. • Reduction in the MIC of antibiotics was observed after complementation of luxS. • Downregulation of efflux pump genes was observed after complementation of luxS. • Transcriptome analysis showed that 204 genes were differentially regulated significantly.


Assuntos
Antibacterianos/farmacologia , Bactérias/genética , Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Liases de Carbono-Enxofre/genética , Resistência Microbiana a Medicamentos/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/fisiologia , Perfilação da Expressão Gênica , Teste de Complementação Genética , Proteínas de Membrana Transportadoras/genética , Testes de Sensibilidade Microbiana , Percepção de Quorum/efeitos dos fármacos
19.
Microb Pathog ; 143: 104124, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32169492

RESUMO

A putative multicopper oxidase, encoded as CopA in the proteome of Acinetobacter baumannii 19606, and designated as AbMCO, was expressed heterologously in E. coli (pET-28a) and purified by Ni-NTA affinity chromatography. The purified AbMCO exhibited in vitro oxidase activities upon exogenous addition of ≥1 µM copper ions. Kinetic studies revealed its phenol oxidase activity as it could catalyze the oxidation of substrates viz. 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), guaiacol, pyrogallol and catechol. Additionally, AbMCO displayed siderophore oxidase activity which depicted its role in metal homeostasis and protection from the toxic redox states of copper and iron. Importantly, expression of abMCO increased manifold upon challenge with high concentrations of copper sulphate (CuSO4, 1.5 mM) and sodium chloride (NaCl, 700 mM) which suggested its protective role in stress adaptation and management. Intra-macrophage assay of abMCO-expressing and abMCO-non expressing cells depicted no significant change in the survival rate of A. baumannii inside the macrophages. These findings indicate that A. baumannii encodes a multicopper oxidase, conferring copper tolerance and survival under stress conditions but had no role in virulence of this pathogen.


Assuntos
Acinetobacter baumannii/enzimologia , Proteínas de Bactérias/metabolismo , Oxirredutases/metabolismo , Acinetobacter baumannii/metabolismo , Acinetobacter baumannii/patogenicidade , Proteínas de Bactérias/isolamento & purificação , Clonagem Molecular , Cobre/metabolismo , Homeostase , Metais/metabolismo , Oxirredutases/isolamento & purificação , Estresse Fisiológico , Virulência
20.
Int J Med Microbiol ; 309(8): 151354, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31495663

RESUMO

New frontiers of therapy are being explored against the upcoming bacterial diseases rendered untreatable due to multiple, extreme and pan- antibiotic resistance. Nucleases are ubiquitous in bacterial pathogens performing various functions like acquiring nucleotide nutrients, allowing or preventing uptake of foreign DNA, controlling biofilm formation/dispersal/architecture, invading host by tissue damage, evading immune defence by degrading DNA matrix of neutrophil extracellular traps (NETs) and immunomodulating the host immune response. Secretory nucleases also provide means of survival to other bacteria like iron-reducing Shewanella and such functions help them adapt and survive proficiently. Other than their pro-pathogen roles in survival, nucleases can be used directly as therapeutics. One of the powerful armours of pathogens is the formation of biofilms, thus helping them resist and persist in the harshest of environments. As eDNA forms the structural and binding component of biofilm, nucleases can be used against the adhering component, thus increasing the permeability of antimicrobial agents. Nucleases have recently become a model system of intense study for their biological functions and medical applications in diagnosis, immunoprophylaxis and therapy. Rational implications of these enzymes can impact human medicine positively in future by opening new ways for therapeutics which have otherwise reached saturation due to multi drug resistance.


Assuntos
Bactérias/enzimologia , Infecções Bacterianas/diagnóstico , Proteínas de Bactérias/metabolismo , Desoxirribonucleases/metabolismo , Fatores de Virulência/metabolismo , Animais , Bactérias/efeitos dos fármacos , Bactérias/patogenicidade , Infecções Bacterianas/tratamento farmacológico , Biofilmes , Biomarcadores , Descoberta de Drogas , Humanos , Camundongos
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