Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 45
Filtrar
1.
Molecules ; 26(1)2020 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-33375633

RESUMO

An evaluation of antioxidant and anticancer activity was screened in Leptocarpha rivularis DC flower extracts using four solvents (n-hexane (Hex), dichloromethane (DCM), ethyl acetate (AcOEt), and ethanol (EtOH)). Extracts were compared for total extract flavonoids and phenol contents, antioxidant activity (2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), ferric reducing antioxidant potential (FRAP), total reactive antioxidant properties (TRAP) and oxygen radical absorbance capacity (ORAC)) across a determined value of reduced/oxidized glutathione (GSH/GSSG), and cell viability (the sulforhodamine B (SRB) assay). The most active extracts were analyzed by chromatographic analysis (GC/MS) and tested for apoptotic pathways. Extracts from Hex, DCM and AcOEt reduced cell viability, caused changes in cell morphology, affected mitochondrial membrane permeability, and induced caspase activation in tumor cell lines HT-29, PC-3, and MCF-7. These effects were generally less pronounced in the HEK-293 cell line (nontumor cells), indicating clear selectivity towards tumor cell lines. We attribute likely extract activity to the presence of sesquiterpene lactones, in combination with other components like steroids and flavonoids.


Assuntos
Antineoplásicos Fitogênicos/química , Asteraceae/química , Neoplasias/tratamento farmacológico , Extratos Vegetais/química , Antineoplásicos Fitogênicos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Flavonoides/química , Flores/química , Células HEK293 , Humanos , Fenóis/química , Fenóis/farmacologia , Extratos Vegetais/farmacologia
2.
Molecules ; 23(9)2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-30213053

RESUMO

Six new cyclodiprenyl phenols were synthesized by direct coupling of perillyl alcohol and the appropriate phenol. Their structures were established by IR, HRMS and mainly NMR. Three human cancer cell lines-breast (MCF-7), prostate (PC-3) and colon (HT-29)-were used in antiproliferative assays, with daunorubicin and dunnione as positive controls. Results described in the article suggest that dihydroxylated compounds 2⁻4 and monohydroxylated compound 5 display selectivity against cancer cell lines, cytotoxicity, apoptosis induction, and mitochondrial membrane impairment capacity. Compound 2 was identified as the most effective of the series by displaying against all cancer cell lines a cytotoxicity close to dunnione antineoplastic agent, suggesting that the cyclodiprenyl phenols from perillyl alcohol deserve more extensive investigation of their potential medicinal applications.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Fenóis/síntese química , Fenóis/farmacologia , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HT29 , Humanos , Células MCF-7 , Membranas Mitocondriais/efeitos dos fármacos , Estrutura Molecular , Fenóis/química , Relação Estrutura-Atividade
3.
Biochim Biophys Acta ; 1852(5): 693-708, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25572853

RESUMO

A considerable body of evidence exists implicating high levels of free saturated fatty acids in beta pancreatic cell death, although the molecular mechanisms and the signaling pathways involved have not been clearly defined. The membrane protein caveolin-1 has long been implicated in cell death, either by sensitizing to or directly inducing apoptosis and it is normally expressed in beta cells. Here, we tested whether the presence of caveolin-1 modulates free fatty acid-induced beta cell death by reexpressing this protein in MIN6 murine beta cells lacking caveolin-1. Incubation of MIN6 with palmitate, but not oleate, induced apoptotic cell death that was enhanced by the presence of caveolin-1. Moreover, palmitate induced de novo ceramide synthesis, loss of mitochondrial transmembrane potential and reactive oxygen species (ROS) formation in MIN6 cells. ROS generation promoted caveolin-1 phosphorylation on tyrosine-14 that was abrogated by the anti-oxidant N-acetylcysteine or the incubation with the Src-family kinase inhibitor, PP2 (4-amino-5-(4-chlorophenyl)-7(dimethylethyl)pyrazolo[3,4-d]pyrimidine). The expression of a non-phosphorylatable caveolin-1 tyrosine-14 to phenylalanine mutant failed to enhance palmitate-induced apoptosis while for MIN6 cells expressing the phospho-mimetic tyrosine-14 to glutamic acid mutant caveolin-1 palmitate sensitivity was comparable to that observed for MIN6 cells expressing wild type caveolin-1. Thus, caveolin-1 expression promotes palmitate-induced ROS-dependent apoptosis in MIN6 cells in a manner requiring Src family kinase mediated tyrosine-14 phosphorylation.


Assuntos
Apoptose/efeitos dos fármacos , Caveolina 1/metabolismo , Células Secretoras de Insulina/efeitos dos fármacos , Palmitatos/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Acetilcisteína/farmacologia , Animais , Western Blotting , Caveolina 1/genética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Sequestradores de Radicais Livres/farmacologia , Peróxido de Hidrogênio/farmacologia , Células Secretoras de Insulina/metabolismo , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Microscopia Confocal , Oxidantes/farmacologia , Fosforilação/efeitos dos fármacos , Pirimidinas/farmacologia , Esfingosina/análogos & derivados , Esfingosina/farmacologia , Tirosina/metabolismo , Quinases da Família src/antagonistas & inibidores , Quinases da Família src/metabolismo
4.
Mol Syst Biol ; 10: 722, 2014 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-24682507

RESUMO

The metazoan genome is replicated in precise cell lineage-specific temporal order. However, the mechanism controlling this orchestrated process is poorly understood as no molecular mechanisms have been identified that actively regulate the firing sequence of genome replication. Here, we develop a mechanistic model of genome replication capable of predicting, with accuracy rivaling experimental repeats, observed empirical replication timing program in humans. In our model, replication is initiated in an uncoordinated (time-stochastic) manner at well-defined sites. The model contains, in addition to the choice of the genomic landmark that localizes initiation, only a single adjustable parameter of direct biological relevance: the number of replication forks. We find that DNase-hypersensitive sites are optimal and independent determinants of DNA replication initiation. We demonstrate that the DNA replication timing program in human cells is a robust emergent phenomenon that, by its very nature, does not require a regulatory mechanism determining a proper replication initiation firing sequence.


Assuntos
Cromatina/ultraestrutura , Período de Replicação do DNA/genética , Replicação do DNA/genética , Cromatina/genética , Genoma Humano , Humanos , Modelos Genéticos , Origem de Replicação/genética
5.
Mol Cancer ; 13: 209, 2014 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-25204429

RESUMO

Early in cancer development, tumour cells express vascular endothelial growth factor (VEGF), a secreted molecule that is important in all stages of angiogenesis, an essential process that provides nutrients and oxygen to the nascent tumor and thereby enhances tumor-cell survival and facilitates growth. Survivin, another protein involved in angiogenesis, is strongly expressed in most human cancers, where it promotes tumor survival by reducing apoptosis as well as favoring endothelial cell proliferation and migration. The mechanisms by which cancer cells induce VEGF expression and angiogenesis upon survivin up-regulation remain to be fully established. Since the PI3K/Akt signalling and ß-catenin-Tcf/Lef dependent transcription have been implicated in the expression of many cancer-related genes, including survivin and VEGF, we evaluated whether survivin may favor VEGF expression, release from tumor cells and induction of angiogenesis in a PI3K/Akt-ß-catenin-Tcf/Lef-dependent manner. Here, we provide evidence linking survivin expression in tumor cells to increased ß-catenin protein levels, ß-catenin-Tcf/Lef transcriptional activity and expression of several target genes of this pathway, including survivin and VEGF, which accumulates in the culture medium. Alternatively, survivin downregulation reduced ß-catenin protein levels and ß-catenin-Tcf/Lef transcriptional activity. Also, using inhibitors of PI3K and the expression of dominant negative Akt, we show that survivin acts upstream in an amplification loop to promote VEGF expression. Moreover, survivin knock-down in B16F10 murine melanoma cells diminished the number of blood vessels and reduced VEGF expression in tumors formed in C57BL/6 mice. Finally, in the chick chorioallantoid membrane assay, survivin expression in tumor cells enhanced VEGF liberation and blood vessel formation. Importantly, the presence of neutralizing anti-VEGF antibodies precluded survivin-enhanced angiogenesis in this assay. These findings provide evidence for the existance of a posititve feedback loop connecting survivin expression in tumor cells to PI3K/Akt enhanced ß-catenin-Tcf/Lef-dependent transcription followed by secretion of VEGF and angiogenesis.


Assuntos
Proteínas Inibidoras de Apoptose/metabolismo , Melanoma Experimental/irrigação sanguínea , Neovascularização Patológica/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Repressoras/metabolismo , Transcrição Gênica , Fator A de Crescimento do Endotélio Vascular/metabolismo , beta Catenina/metabolismo , Animais , Galinhas , Membrana Corioalantoide/metabolismo , Regulação para Baixo , Feminino , Células HEK293 , Humanos , Fator 1 de Ligação ao Facilitador Linfoide/metabolismo , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Camundongos , Camundongos Endogâmicos C57BL , Células NIH 3T3 , Neovascularização Patológica/patologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Survivina , Fator A de Crescimento do Endotélio Vascular/genética
6.
Genome Res ; 21(11): 1822-32, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21813623

RESUMO

This report investigates the mechanisms by which mammalian cells coordinate DNA replication with transcription and chromatin assembly. In yeast, DNA replication initiates within nucleosome-free regions, but studies in mammalian cells have not revealed a similar relationship. Here, we have used genome-wide massively parallel sequencing to map replication initiation events, thereby creating a database of all replication initiation sites within nonrepetitive DNA in two human cell lines. Mining this database revealed that genomic regions transcribed at moderate levels were generally associated with high replication initiation frequency. In genomic regions with high rates of transcription, very few replication initiation events were detected. High-resolution mapping of replication initiation sites showed that replication initiation events were absent from transcription start sites but were highly enriched in adjacent, downstream sequences. Methylation of CpG sequences strongly affected the location of replication initiation events, whereas histone modifications had minimal effects. These observations suggest that high levels of transcription interfere with formation of pre-replication protein complexes. Data presented here identify replication initiation sites throughout the genome, providing a foundation for further analyses of DNA-replication dynamics and cell-cycle progression.


Assuntos
Replicação do DNA , Genoma Humano , Origem de Replicação , Transcrição Gênica , Linhagem Celular Tumoral , Cromatina/metabolismo , Ilhas de CpG , Metilação de DNA , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Células K562 , Sítio de Iniciação de Transcrição
7.
Helicobacter ; 19(3): 182-93, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24628778

RESUMO

BACKGROUND: Helicobacter pylori is a motile microaerophilic bacterium that colonizes the human stomach. H. pylori infection triggers gastric diseases, such as gastritis, peptic ulcer and gastric cancer. Stomach represents a barrier for microorganism colonization, particularly because of its high hydrochloric acid concentration. The main mechanism developed by H. pylori to maintain intracellular pH homeostasis in this environment is the urease activity. However, urease negative strains can be also isolated from clinical samples, suggesting that H. pylori presents other components involved in acid resistance. OBJECTIVE: Here, we present some evidence that the arginine decarboxylase gene (speA) in H. pylori could be involved in an acid adaptation mechanism similar to the one in Enterobacteriaceae, which is dependent on the presence of arginine. METHODS: Indeed, speA mRNA and protein expression are acutely induced by acid stress. RESULTS: Moreover, we showed that H. pylori uses arginine in an acid response mechanism required for its growth in acid conditions. CONCLUSION: Altogether, these results provide novel information regarding the H. pylori physiology and acid response mechanism.


Assuntos
Ácidos/toxicidade , Carboxiliases/metabolismo , Tolerância a Medicamentos , Helicobacter pylori/enzimologia , Helicobacter pylori/fisiologia , Carboxiliases/genética , Perfilação da Expressão Gênica , Helicobacter pylori/genética , Homeostase , Humanos , Concentração de Íons de Hidrogênio
8.
J Infect Dis ; 208(7): 1131-41, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-23847060

RESUMO

Helicobacter pylori is the etiologic agent of a series of gastric pathologies that may culminate in the development of gastric adenocarcinoma. An initial step in this process is the loss of glandular structures in the gastric mucosa, presumably as the consequence of increased apoptosis and reduced cellular regeneration, which may be attributed to the combination of several bacterial and host factors and to an unfavorable proinflammatory environment. In a previous study, we showed that survivin, a member of the inhibitor of apoptosis protein family, is expressed in the normal human gastric mucosa and that its levels decrease in the mucosa of infected patients and in gastric cells exposed in culture to the bacteria, coincident with increased cell death in the latter case. We investigated the bacterial factors responsible for loss of survivin in gastric cells exposed to H. pylori. The results of this study indicated that the loss of survivin due to H. pylori infection involves proteasome-mediated degradation of the protein. Studies with isogenic mutants deficient in either CagA, VacA, lipopolysaccharide, or gamma-glutamyl transpeptidase (GGT) implicated the latter in H. pylori-induced loss of survivin and cell viability. Moreover, experiments with the GGT inhibitor 6-diazo-5-oxo-l-norleucine and purified recombinant GGT protein indicated that secreted bacterial GGT activity was required and sufficient to induce these effects.


Assuntos
Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/patologia , Helicobacter pylori/enzimologia , Helicobacter pylori/patogenicidade , Proteínas Inibidoras de Apoptose/metabolismo , Fatores de Virulência/metabolismo , gama-Glutamiltransferase/metabolismo , Linhagem Celular , Deleção de Genes , Humanos , Viabilidade Microbiana , Survivina , Fatores de Virulência/genética , gama-Glutamiltransferase/genética
9.
J Sch Health ; 93(12): 1061-1069, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37867403

RESUMO

BACKGROUND: COVID-19 screening testing (ST) can detect asymptomatic or pre-symptomatic cases, allowing for prompt identification of cases and close contacts. This study examined parents' and school staffs' knowledge and attitudes toward to a pilot school-based ST program in a school district in southern Arizona. METHODS: In May 2021, online surveys to parents and school staff were administered to examine attitudes toward ST and impacts of the COVID-19 pandemic. Unweighted percent estimates were calculated, and bivariate differences were examined by demographics. Associations were assessed using chi-square tests and logistic regression. RESULTS: The survey had response rates of 10% (606/6085) and 22% (187/849) among parents and staff, respectively. Approximately one-third of responding parents (35%) would or already allow their child to participate in school-based ST, 37% would not participate; 28% were unsure. Among responding staff, 46% would or already participate in ST, 33% would not; 21% were unsure. The top concern (38%) among responding staff was taking job-related leave if testing positive. CONCLUSION: Schools work to balance the needs of students, families, and staff by implementing supportive and flexible policies and practices founded on buy-in and acceptance from their communities.


Assuntos
COVID-19 , Criança , Humanos , Estados Unidos , COVID-19/diagnóstico , COVID-19/epidemiologia , Pandemias , Instituições Acadêmicas , Teste para COVID-19 , Pais
10.
J Cell Biochem ; 113(1): 132-40, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21898540

RESUMO

Human DNA replication depends on the activation of thousands of origins distributed within the genome. The actual distribution of origins is not known, nor whether this distribution is unique to a cell type, or if it changes with the proliferative state of the cell. In this study, we have employed a real-time PCR-based nascent strand DNA abundance assay, to determine the location of origins along a 78 kb region on Chr2q34. Preliminary studies using nascent DNA strands isolated from either HeLa and normal skin fibroblast cells showed that in both cell lines peaks of high origin activity mapped in similar locations. However, the overall origin profile in HeLa cells corresponded to broad origin activation zones, whereas in fibroblasts a more punctuated profile of origin activation was observed. To investigate the relevance of this differential origin profile, we compared the origin distribution profiles in breast cancer cell lines MDA-MB-231, BT-474, and MCF-7, to their normal counterpart MCF-10A. In addition, the CRL7250 cell line was also used as a normal control. Our results validated our earlier observation and showed that the origin profile in normal cell lines exhibited a punctuated pattern, in contrast to broader zone profiles observed in the cancer cell lines. A quantitative analysis of origin peaks revealed that the number of activated origins in cancer cells is statistically larger than that obtained in normal cells, suggesting that the flexibility of origin usage is significantly increased in cancer cells compared to their normal counterparts.


Assuntos
Cromossomos Humanos Par 2/genética , Replicação do DNA/genética , Complexo de Reconhecimento de Origem/metabolismo , Origem de Replicação/genética , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Mapeamento Cromossômico , Feminino , Fibroblastos/metabolismo , Células HeLa , Humanos , Reação em Cadeia da Polimerase em Tempo Real/métodos
11.
Helicobacter ; 17(1): 16-22, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22221611

RESUMO

BACKGROUND: Helicobacter pylori colonizes the gastric mucosa and must survive the acid pH of that environment. Like other enteric bacterial pathogens, including Salmonella enterica, H. pylori develops an acid tolerance response that is dependent on the function of the transcriptional regulator protein Fur. OBJECTIVE: To explore by site-directed mutagenesis whether two particular amino acid residues in the amino acid sequence of the H. pylori Fur protein, arginine 66 and histidine 99, are involved in the acid response mechanism in this bacterium. MATERIALS AND METHODS: Complementation assays in Escherichia coli H1780 (fur null mutant) both with plasmids carrying the H. pylori fur gene bearing substitution mutations R66A or H99A or R66A/H99A and with the H. pylori Fur-R66A mutant were conducted. Wild-type and mutated Fur proteins from H. pylori were assayed by using the fiu::lacZ reporter gene in the E. coli H1780 heterologous system at various pH and iron concentrations. RESULTS: Both bacterial growth and repression of the reporter gene were impaired under acid conditions in E. coli H1780 complemented with pUC19-fur-R66A. Also, in the H. pylori Fur-R66 strain bacterial growth and speA gene expression were impaired under acid conditions. CONCLUSIONS: Arginine 66 but not histidine 99 in H. pylori Fur is required for the regulatory function of the Fur protein in the acid adaptation mechanism of the bacterium.


Assuntos
Arginina/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Helicobacter pylori/metabolismo , Sequência de Aminoácidos , Arginina/metabolismo , Proteínas de Bactérias/química , Mucosa Gástrica/microbiologia , Regulação Bacteriana da Expressão Gênica , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Helicobacter pylori/crescimento & desenvolvimento , Histidina/genética , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Mutação , Alinhamento de Sequência , Transcrição Gênica
12.
Int J Med Mushrooms ; 14(6): 563-73, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23510250

RESUMO

The main objective of this study was to evaluate the antioxidant capacity of methanolic extracts from species of genus Phellinus: Ph. fastuosus, Ph. grenadensis, Ph. Merrillii, and Ph. Badius, in their respective polar fractions (aqueous) and nonpolar extracts (ethyl acetate), through tests of free-radical inactivation and hemolysis inhibition. The fungus species that gave the extract with the highest phenol content, total flavonoids, and antioxidant capacity [DPPH·, Trolox equivalents antioxidant capacity (TEAC), and hemolysis inhibition] was Ph. Merrillii, followed by Ph. fastuosus, Ph. Grenadensis, and Ph. Badius. The antioxidant capacities of the extracts, in descending order, were as follows: Ph. Merrillii (nonpolar), Ph. Fastuosus (nonpolar), Ph. Grenadensis (nonpolar), Ph. Fastuosus (polar), Ph. Merrillii (polar), Ph. Grenadensis (polar), Ph. Badius (nonpolar), and Ph. Badius (polar). Antioxidant capacity in the above Phellinus fungi species had EC50 values for DPPH inhibition of 0.45, 0.88, 1.31, 1.89, 2.14, 2.22, 3.42, and 6.00 mg/mL, respectively; TEAC values of 10400.29, 7635.53, 4855.05, 4415.39, 4041.68, 2989.2, 1937.7, and 842.42 µmol TE/g, respectively; and hemolysis inhibition values of 72.83, 66.95, 50.87, 50.28, 48.5, 42.82, 42.37, and 37.91%, respectively. In general, the fungus extract with the highest antioxidant capacity was the nonpolar fraction of Ph. Merrillii. The Phellinus species studied represent potential natural sources of bioactive compounds with antioxidant activity.


Assuntos
Antioxidantes/química , Basidiomycota/química , Flavonoides/farmacologia , Fenóis/farmacologia , Cromanos/química , Flavonoides/química , Hemólise , Humanos , Metanol , Fenóis/química , Especificidade da Espécie
13.
Insects ; 13(8)2022 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-36005367

RESUMO

Chili pepper is a vegetable of worldwide economic and gastronomic importance. The psyllid, Bactericera cockerelli, is an economically important pest in this crop, causing considerable losses in its production. Currently, the application of insecticides is the main way to control B. cockerelli. However, the use of varieties resistant to this insect is a viable alternative for its control and management. In this work, the oviposition rate, development, and survival of B. cockerelli in two native varieties of chili were evaluated. Choice and non-choice trials showed that the B. cockerelli oviposition was reduced on CJ-2018 by 92.17 and 80.18%, respectively, compared to the control. In CM-334, the insect showed a behavior similar to the control in the non-choice test, while in the choice test it laid more eggs on CM-334 compared to the control. The development and survival assay showed that only 1.33% of the eggs managed to reach the adult stage on CJ-2018. In contrast, on CM-334 the survival of B. cockerelli was similar to the control. These results suggest that CJ-2018 presented a resistance based on antixenosis and antibiosis against B. cockerelli.

14.
Braz J Microbiol ; 53(3): 1187-1197, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35380361

RESUMO

Phellinus Quél is one of the largest genera of Hymenochaetaceae; it comprises about 220 species widely distributed on Earth. Most Phellinus species are lignicolous mushrooms that accumulate bioactive compounds. This research studied the phenolic composition of Phellinus spp. and their relationship with antibacterial and antiviral capacity. Phenolics were extracted from Phellinus badius, P. fastuosus, and P. grenadensis; their antiviral and antibacterial activities were evaluated against Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica, and Escherichia coli O157: H7; and the bacteriophages MS2 and Φ- × 174. Gallic acid, chlorogenic acid, caffeic acid, epicatechin, ferulic acid, catechin, 1,3-dicaffeoylquinic acid, p-coumaric acid, and rutin were found in different proportions among Phellinus spp. Total phenolic content ranged from 96 to 209 mg GAE/g, and total flavonoids from 10 to 27 QE/g. The minimum inhibitory concentrations of P. badius, P. grenadensis, and P. fastuosus against E. coli O157: H7 were 13, 20, and 27 mg/mL, against S. enterica were 20, 30, and 15 mg/mL, and against L. monocytogenes were 10, 15, and 25 mg/mL, respectively. The phenolic content was better correlated with the antibacterial effect against E. coli O157: H7 and L. monocytogenes (r = 0.8-0.9), but not against S. enterica (r = 0.05). The antiviral activity of the extracts (0.9 mg/mL) was 29 to 41% against MS2 and 27 to 38% for Φ-X174 virus (r = 0.8-0.9). In silico analysis showed binding energy values of - 7.9 and - 4.8 kcal/mol between the identified phenolic compounds and the M and G proteins of each virus. The antibacterial and antiviral properties of Phellinus species were correlated with the phenolic content.


Assuntos
Escherichia coli O157 , Listeria monocytogenes , Antibacterianos/farmacologia , Antivirais/análise , Antivirais/farmacologia , Microbiologia de Alimentos , Phellinus , Fenóis/análise , Fenóis/farmacologia
15.
Foods ; 11(17)2022 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-36076774

RESUMO

Aqueous and ethanolic pomegranate peel extracts (PPE) were studied as a source of phenolic compounds with antimicrobial, anti-quorum sensing, and antioxidant properties. The aqueous extract showed higher total phenolic and flavonoid content (153.43 mg GAE/g and 45.74, respectively) and antioxidant capacity (DPPH radical inhibition: 86.12%, ABTS radical scavenging capacity: 958.21 mg TE/dw) compared to the ethanolic extract. The main phenolic compounds identified by UPLC-DAD were chlorogenic and gallic acids. The aqueous PPE extract showed antimicrobial activity against Listeria monocytogenes, Salmonella Typhimurium, Candida tropicalis (MICs 19-30 mg/mL), and anti-quorum sensing activity expressed as inhibition of Chromobacterium violaceum violacein production (%). The aqueous PPE extracts at 25 mg/mL applied on alfalfa sprouts reduced psychrophilic bacteria (1.12 Log CFU/100 g) and total coliforms (1.23 Log CFU/100 g) and increased the antioxidant capacity of the treated sprouts (55.13 µmol TE/100 g (DPPH) and 126.56 µmol TE/100 g (ABTS)) compared to untreated alfalfa. This study emphasizes PPE's antioxidant and antimicrobial activities in alfalfa sprouts preservation.

16.
Helicobacter ; 16(3): 189-99, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21585604

RESUMO

BACKGROUND: Helicobacter pylori colonizes the acid environment of the gastric mucosa. Like other enteric bacterial pathogens, including Salmonella enterica, which must survive a brief exposure to that environment, H. pylori displays a rapid response to subtle changes in pH, which confers an increased ability to survive at more extreme acidic pH. This two-step acid tolerance response (ATR) requires de novo protein synthesis and is dependent on the function of the global regulatory protein Fur. OBJECTIVE: We have explored the physiological bases of the ATR in H. pylori. MATERIALS AND METHODS: Proteomic analysis of phenotypes of H. pylori and fur mutant strains show that subtle pH changes elicit significant changes in the pattern of proteins synthesized. RESULTS: A loss-of-function mutation in the fur gene, obtained by insertion of an antibiotic resistance cassette, indicated that Fur regulates the expression of a fraction of H. pylori proteins. CONCLUSION: A subset of proteins is involved in the ATR and confer a negative ATR phenotype.


Assuntos
Ácidos/metabolismo , Proteínas de Bactérias/metabolismo , Helicobacter pylori/metabolismo , Proteínas Repressoras/metabolismo , Proteínas de Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Helicobacter pylori/genética , Proteínas Repressoras/genética
17.
J Infect Dis ; 202(7): 1021-30, 2010 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-20735270

RESUMO

Helicobacter pylori infects the human stomach and modifies signaling pathways that affect gastric epithelial cell proliferation and viability. Chronic exposure to this pathogen contributes to the onset of gastric atrophy, an early event in the genesis of gastric cancer associated with H. pylori infection. Susceptibility to H. pylori-induced cell death ultimately depends on the presence of protective host cell factors. Although expression of the inhibitor-of-apoptosis protein survivin in adults is frequently linked to the development of cancer, evidence indicating that the protein is present in normal gastric mucosa is also available. Thus, we investigated in human gastric tissue samples and cell lines whether H. pylori infection is linked to loss of survivin and increased cell death. Our results show that infection with H. pylori decreased survivin protein levels in the mucosa of patients with gastritis. Furthermore, survivin down-regulation correlated with apoptosis and loss of cell viability in gastrointestinal cells cocultured with different H. pylori strains. Finally, overexpression of survivin in human gastric cells was sufficient to reduce cell death after infection. Taken together, these findings implicate survivin as an important survival factor in the gastric mucosa of humans.


Assuntos
Morte Celular , Mucosa Gástrica/química , Gastrite/patologia , Helicobacter pylori/patogenicidade , Proteínas Inibidoras de Apoptose/análise , Proteínas Associadas aos Microtúbulos/análise , Adulto , Técnicas de Cocultura , Mucosa Gástrica/patologia , Gastrite/microbiologia , Humanos , Survivina
18.
Biomedicines ; 9(11)2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34829898

RESUMO

Bacterial diseases and reactive oxygen species can cause dental caries and oral cancer. Therefore, the present review analyzes and discusses the antibacterial and antioxidant properties of synthetic and plant-derived substances and their current and future patents to formulate dental products. The reviewed evidence indicates that chlorhexidine, fluorides, and hydrogen peroxide have adverse effects on the sensory acceptability of oral care products. As an alternative, plant-derived substances have antimicrobial and antioxidant properties that can be used in their formulation. Also, adding plant metabolites favors the sensory acceptability of dental products compared with synthetic compounds. Therefore, plant-derived substances have antibacterial, antioxidant, and flavoring activity with the potential to be used in the formulation of toothpaste, mouth rinses, dentures cleansers-fixatives, and saliva substitutes.

19.
World J Gastroenterol ; 24(28): 3071-3089, 2018 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-30065554

RESUMO

Helicobacter pylori (H. pylori) is present in roughly 50% of the human population worldwide and infection levels reach over 70% in developing countries. The infection has classically been associated with different gastro-intestinal diseases, but also with extra gastric diseases. Despite such associations, the bacterium frequently persists in the human host without inducing disease, and it has been suggested that H. pylori may also play a beneficial role in health. To understand how H. pylori can produce such diverse effects in the human host, several studies have focused on understanding the local and systemic effects triggered by this bacterium. One of the main mechanisms by which H. pylori is thought to damage the host is by inducing local and systemic inflammation. However, more recently, studies are beginning to focus on the effects of H. pylori and its metabolism on the gastric and intestinal microbiome. The objective of this review is to discuss how H. pylori has co-evolved with humans, how H. pylori presence is associated with positive and negative effects in human health and how inflammation and/or changes in the microbiome are associated with the observed outcomes.


Assuntos
Microbioma Gastrointestinal/fisiologia , Infecções por Helicobacter/fisiopatologia , Helicobacter pylori/fisiologia , Interações Hospedeiro-Patógeno/fisiologia , Inflamação/fisiopatologia , Coevolução Biológica/fisiologia , Mucosa Gástrica/microbiologia , Mucosa Gástrica/fisiopatologia , Infecções por Helicobacter/epidemiologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/patogenicidade , Humanos , Inflamação/microbiologia
20.
Artigo em Inglês | MEDLINE | ID: mdl-29552079

RESUMO

Antioxidants are known to be beneficial to health. This paper evaluates the potential chemopreventive and anticancer properties of phenolic compounds present in grape juice extracts (GJE) from Autumn Royal and Ribier varieties. The effects of these GJE on viability (SRB day assay) and metastatic potential (migration and invasion parameters) of colon cancer cell lines HT-29 and SW-480 were evaluated. The effects of GJE on two matrix metalloproteinase gene expressions (MMP2 and MMP9) were also evaluated via qRT-PCR. In the former, GJE reduced cell viability in both cell lines in a dose-dependent manner. GJE treatment also reduced cell migration and invasion. Moreover, MMP-2 and MMP-9 gene expression diminished depending on extract and on cell type. Conclusions. These results provide novel information concerning anticancer properties of selected GJE by revealing selective cytotoxicity and the ability to reduce invasiveness of colon cancer cells.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA