Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
Mais filtros

País/Região como assunto
Intervalo de ano de publicação
1.
Oral Dis ; 24(6): 930-939, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29667275

RESUMO

OBJECTIVES: MicroRNAs play a role in the development and progression of head and neck squamous cell carcinomas (HNSCC). Our aim was to study the expression of miR-26, miR-107, miR-125b, and miR-203 in primary HNSCC with and without lymph node metastasis and their clinicopathological significance. MATERIALS AND METHODS: The expression of microRNAs in primary HNSCC with lymph node metastasis (n = 16) and their matched lymph node, as well as primary tumors without metastasis (n = 16), were determined by quantitative RT-PCR and analyzed with clinicopathological features and survival. RESULTS: The expression levels of miR-26 (p < .05) and miR-125b (p < .01) were higher in metastatic primary HNSCC, while levels of miR-203 (p < .01) were lower. The expression of the microRNAs was associated with clinicopathological features, including miR-26 high expression and N stage (p = .04), poor differentiation (p = .005) and recurrence (p = .007), miR-125b high expression and N stage (p = .0005) and death (p = .02), and low levels of miR-203 and N stage (p = .04). The high expression of miR-26 was associated with shortened disease-free survival, and high miR-125b expression was an independent risk factor for poor disease-specific survival. CONCLUSIONS: These findings suggest that miR-26 and miR-125b may be associated with the progression and metastasis of HNSCC and that miR-203 is associated with a more favorable prognosis.


Assuntos
Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/secundário , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/patologia , MicroRNAs/genética , Idoso , Intervalo Livre de Doença , Feminino , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Estadiamento de Neoplasias , Taxa de Sobrevida
2.
Oral Dis ; 24(5): 725-731, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28887832

RESUMO

BACKGROUND: A new intercellular communication mode established by neoplastic cells and tumor microenvironment components is based on extracellular vesicles (EVs). However, the biological effects of the EVs released by tumor cells on angiogenesis are not completely understood. Here, we aimed to understand the biological effects of EVs isolated from two cell lines of oral squamous cell carcinoma (OSCC) (SCC15 and HSC3) on endothelial cell tubulogenesis. METHODS: OSCC-derived EVs were isolated with a polymer-based precipitation method, quantified using nanoparticle tracking analysis and verified for EV markers by dot blot. Functional assays were performed to assess the angiogenic potential of the OSCC-derived EVs. RESULTS: The results showed that EVs derived from both cell lines displayed typical spherical-shaped morphology and expressed the EV markers CD63 and Annexin II. Although the average particle concentration and size were quite similar, SCC15-derived EVs promoted a pronounced tubular formation associated with significant migration and apoptosis rates of the endothelial cells, whereas EVs derived from HSC3 cells inhibited significantly endothelial cell tubulogenesis and proliferation. CONCLUSION: The findings of this study reveal that EVs derived from different OSCC cell lines by a polymer-based precipitation method promote pro- or anti-angiogenic effects.


Assuntos
Carcinoma de Células Escamosas/fisiopatologia , Vesículas Extracelulares/fisiologia , Células Endoteliais da Veia Umbilical Humana/fisiologia , Neoplasias Bucais/fisiopatologia , Neovascularização Patológica/fisiopatologia , Apoptose , Comunicação Celular , Linhagem Celular Tumoral , Movimento Celular , Humanos
3.
Eur J Oral Sci ; 125(4): 247-257, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28653423

RESUMO

Angiotensin II (Ang II) is the product of the proteolytic action of angiotensin-converting enzyme (ACE) on the precursor peptide, angiotensin I (Ang I). In addition to its vasoactive properties, Ang II is able to stimulate angiogenesis and act as a mitogen, promoting cellular proliferation. Recently, evidence has emerged that Ang II is also able to promote tumour invasion, a key step in the metastatic cascade, although the mechanisms by which it does so remain largely obscure. Here we show that Ang II is able to promote the invasion and migration of head and neck squamous cell carcinoma (HNSCC) cells both in an autocrine manner and by triggering stromal tumour-paracrine interactions. The effects of Ang II on autocrine and paracrine signalling pathways are mediated by angiotensin receptor 1 (AT1 R) and inhibited by angiotensin 1-7 (Ang 1-7), a peptide produced from Ang II by the action of angiotensin-converting enzyme 2 (ACE2). These data are the first to demonstrate a role for the renin-angiotensin system in oral carcinogenesis and raise the possibility of utilizing AT1 R receptor antagonists and/or Ang 1-7 as novel therapeutic agents for HNSCC.


Assuntos
Angiotensina II/metabolismo , Angiotensina I/farmacologia , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/patologia , Fragmentos de Peptídeos/farmacologia , Técnicas de Cultura de Células , Movimento Celular , Progressão da Doença , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Immunoblotting , Reação em Cadeia da Polimerase , Sistema Renina-Angiotensina/fisiologia , Transdução de Sinais , Transfecção , Células Tumorais Cultivadas
4.
Phys Rev Lett ; 114(20): 203901, 2015 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-26047230

RESUMO

We study theoretically and experimentally the propagation of optical solitons in a lattice nonlinearity, a periodic pattern that both affects and is strongly affected by the wave. Observations are carried out using spatial photorefractive solitons in a volume microstructured crystal with a built-in oscillating low-frequency dielectric constant. The pattern causes an oscillating electro-optic response that induces a periodic optical nonlinearity. On-axis results in potassium-lithium-tantalate-niobate indicate the appearance of effective continuous saturated-Kerr solitons, where all spatial traces of the lattice vanish, independently of the ratio between beam width and lattice constant. Decoupling the lattice nonlinearity allows the detection of discrete delocalized and localized light distributions, demonstrating that the continuous solitons form out of the combined compensation of diffraction and of the underlying periodic volume pattern.

5.
Genet Mol Res ; 12(4): 4967-71, 2013 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-24301757

RESUMO

The chimeric oncogene BCR/ABL, which is the product of reciprocal translocation between chromosomes 9 and 22, is a known molecular marker of chronic myeloid leukemia (CML), and is related to the major factors involved in leukemogenesis. Some previous studies have also reported the presence of this oncogene in peripheral blood cells of healthy individuals. In this study, we investigated the presence of BCR/ABL transcripts in peripheral blood of individuals aged 40 years or more without symptoms of CML. The presence of BCR/ABL transcripts was observed in 2 of the 30 individuals analyzed. The genesis of BCR/ABL transcripts and its presence in healthy individuals are topics of ongoing debate. The risks and biological implications of the presence of BCR/ABL transcripts in healthy individuals are challenging issues that remain to be elucidated.


Assuntos
Proteínas de Fusão bcr-abl/genética , Voluntários Saudáveis , Transcrição Gênica , Adulto , Feminino , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucócitos Mononucleares/metabolismo , Masculino , Pessoa de Meia-Idade , Translocação Genética
6.
Braz J Microbiol ; 44(1): 29-35, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24159280

RESUMO

This study evaluated the influence of the phenolic compounds carvacrol (CAR) and thymol (THY) on some physiological characteristics and on the modulation of the secretion of some staphylococcal virulence factors, that is, coagulase and enterotoxin. This study also investigated possible mechanisms for the establishment of the anti-staphylococcal activity of these compounds. Sublethal concentrations (0.3 and 0.15 µL/mL) of CAR and THY inhibited the activity of the enzymes coagulase and lipase and led to a decrease in salt tolerance. At the tested sublethal concentrations, both CAR and THY led to a total suppression of enterotoxin production. The loss of a 260-nm-absorbing material and an efflux of potassium ions occurred immediately after the addition of CAR and THY at 0.6 and 1.2 µL/mL and increased up to 120 min of exposure. Electron microscopy of cells exposed to CAR and THY (0.6 µL/mL) revealed that individual cells appeared to be deformed, with projections of cellular material. The observations of leakage of cellular material and an altered cell surface suggest that gross damage to a cell's cytoplasmic membrane, which results in a disruption in protein secretion, could be responsible for the anti-staphylococcal properties of CAR and THY.

7.
Int J Parasitol Parasites Wildl ; 22: 14-19, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37584011

RESUMO

Coatis (Nasua nasua) are wild carnivorous well adapted to anthropized environments especially important because they act as reservoirs hosts for many arthropod-borne zoonotic pathogens. Information about filarioids from coatis and associated Wolbachia spp. in Brazil is scant. To investigate the diversity of filarial nematodes, blood samples (n = 100 animals) were obtained from two urban areas in midwestern Brazil and analyzed using blood smears and buffy coats and cPCR assays based on the cox1, 12S rRNA, 18S rRNA, hsp70 and myoHC genes for nematodes and 16S rRNA for Wolbachia. When analyzing coati blood smears and buffy coats, 30% and 80% of the samples presented at least one microfilaria, respectively. Twenty-five cox1 sequences were obtained showing 89% nucleotide identity with Mansonella ozzardi. Phylogenetic analyses clustered cox1 sequences herein obtained within the Mansonella spp. clade. Sequences of both myoHC and two hsp70 genes showed 99.8% nucleotide identity with Mansonella sp. and clustered into a clade within Mansonella sp., previously detected in coatis from Brazil. Two blood samples were positive for Wolbachia, with a 99% nucleotide identity with Wolbachia previously found in Mansonella perstans, Mansonella ozzardi and Mansonella atelensis and in ectoparasites of the genus Pseudolynchia, Melophagus and Cimex. The study showed a high prevalence of Mansonella sp. in the coati population examined, suggesting that this animal species play a role as reservoirs of a novel, yet to be described, species within the Onchocercidae family.

8.
Eur J Clin Microbiol Infect Dis ; 31(6): 1271-7, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22120419

RESUMO

We have identified impaired neutrophils in elderly individuals which could be involved with Candida-related denture stomatitis (DS), an oral infection predominantly caused by Candida albicans, affecting especially elderly individuals using dental prosthesis. However, specific mechanisms performed by neutrophil contributing to the susceptibility of the elderly to DS are not fully understood. This study evaluated activation features of blood neutrophils from elderly and young individuals with DS. Blood neutrophils cultured with C. albicans from elderly subjects secreted decreased levels of CXCL8. However, C. albicans challenged-neutrophils from DS patients produced high IL-4 and IL-10, and low GM-CSF levels, regardless of age. Additional elastase activity of neutrophils from both elderly groups was detected after incubation with C. albicans, but only neutrophils from elderly DS demonstrated high myeloperoxidase activity. Therefore, DS patients have affected neutrophils, and the advance of age intensifies these damages. In summary, individuals with Candida-related denture stomatitis presented variation in the neutrophil phenotype and activation. Such alterations were more intense in neutrophils from infected elderly individuals.


Assuntos
Sangue/imunologia , Candida albicans/imunologia , Candidíase Bucal/imunologia , Ativação de Neutrófilo , Estomatite sob Prótese/imunologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Candida albicans/patogenicidade , Células Cultivadas , Citocinas/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Elastase Pancreática/metabolismo , Peroxidase/metabolismo
9.
Neotrop Entomol ; 47(4): 484-491, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28823108

RESUMO

Physiological constraints in insects are related to several large-scale processes such as species distribution and thermal adaptation. Here, we fill an important gap in ecophysiology knowledge by accessing the relationship between temperature and embrionary development time in four dragonfly species. We evaluated two questions (1) what is the effect of temperature on the development time of Odonata eggs, and (2) considering a degree-day relationship, could a simple linear model describe the dependence of embrionary development time on temperature or it is better described by a more complex non-linear relation. Egg development time of Erythrodiplax fusca (Rambur), Micrathyria hesperis Ris, Perithemis mooma Kirby, and Miathyria simplex (Rambur) (Odonata: Libellulidae) were evaluated. We put the eggs at different temperatures (15, 20, 25, and 30°C) and counted the number of hatched larvae daily. A nonlinear response of the development to the temperature was found, differing from the expected pattern for standard degree-day analysis. Furthermore, we observed that there is a similar process in the development time and hatching synchronization between species, with all species presenting faster egg development at high temperatures. Species-specific differences are more evident at lower temperatures (15°C), with no egg development in M. simplex. Only E. fusca was relatively insensitive to temperature changes with similar hatching rates in all treatments.


Assuntos
Odonatos , Óvulo/fisiologia , Temperatura , Animais , Brasil
10.
Transbound Emerg Dis ; 65(2): 476-479, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29034582

RESUMO

A total of 27 seminal plasma samples from cattle-breeding farms or semen centres located in Minas Gerais, Brazil, previously negative by serological and tested positive for Brucella spp. with primer specific for the amplification of the gene virb5 by polymerase chain reaction (PCR) were analysed for the detection of Brucella abortus DNA by PCR. It was found that nine samples (33.33%) contained B. abortus B19 strain DNA, two (7.40%) contained B. abortus DNA and five (18.51%) contained both DNA. The larger number of samples with B. abortus B19 strain DNA would explained by the environmental contamination by vaccinated females with persistent excretion or some illegal vaccination process. It is first reported of male bovines detected with both DNA.


Assuntos
Brucella abortus/genética , Brucella abortus/isolamento & purificação , Brucelose Bovina/diagnóstico , DNA Bacteriano/genética , Sêmen/microbiologia , Animais , Brasil , Brucelose Bovina/microbiologia , Bovinos , Primers do DNA/química , Masculino , Reação em Cadeia da Polimerase/veterinária , Vacinação/veterinária
11.
Transbound Emerg Dis ; 64(6): e36-e42, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28233434

RESUMO

The multihost parasites Leishmania spp. infect a broad range of wild mammalian species including bats. Several species of bats have adapted to a variety of food resources and shelters in urban areas. This study aimed to detect Leishmania spp. DNA in bats present in forest fragments located in metropolitan areas endemic for leishmaniasis in Campo Grande, Mato Grosso do Sul (MS), Brazil. Blood samples were obtained from 80 individuals, including eight species of Phyllostomidae and one species of Vespertilionidae. Thirty of the 80 bats were positive for Leishmania spp. using conventional PCR, all belonging to the family Phyllostomidae. Eighteen samples tested by real-time PCR (qPCR) using specific primers for the kDNA of Leishmania infantum were positive. To the best of our knowledge, this is the first report detecting Leishmania spp. in Platyrrhinus incarum in addition to being the first reported detection of L. infantum in the bat species Phyllostomus discolor, Platyrrhinus lineatus, Artibeus planirostris and Artibeus lituratus. Our results show that bats can host Leishmania spp. in areas endemic for leishmaniasis, which must be taken into account in disease control operations by public health authorities.


Assuntos
Quirópteros , Leishmania/isolamento & purificação , Leishmaniose/veterinária , Animais , Brasil/epidemiologia , Leishmania/classificação , Leishmaniose/epidemiologia , Leishmaniose/parasitologia , Reação em Cadeia da Polimerase em Tempo Real
12.
Equine Vet J ; 49(2): 221-224, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26875684

RESUMO

REASONS FOR PERFORMING STUDY: In August 2014, an outbreak of oral exanthematous disease in equids was reported in Brazil, affecting 11 donkeys and 3 mules. OBJECTIVES: To investigate if Vaccinia virus (VACV) was the aetiological agent in this outbreak. STUDY DESIGN: Investigation of clinical cases using serological, molecular and phylogenetic approaches. METHODS: To analyse the presence of neutralising antibodies against VACV, samples were submitted in triplicate to a plaque-reduction neutralisation test (PRNT50% ). On the basis of previous studies which detected VACV DNA in sera, we submitted extracted DNA samples to different polymerase chain reaction (PCR) platforms targeting Orthopoxvirus (OPV) genes (C11R, A56R and A26L). The PCR products were directly sequenced in both orientations using specific primers and capillary electrophoresis. The alignment and phylogenetic analysis of the A26L and A56R nucleotide sequences (maximum likelihood) were prepared with the obtained nucleotide fragments. RESULTS: Serological and molecular data suggested VACV as the aetiological agent. The neutralising antibodies against OPV were detected in 5 (55.5%) of the equids, with titres ≥40 neutralising u/ml. Based on the results obtained from all PCR platforms, all samples were positive for OPV: 9 (100%) for A56R, 4 (44.4%) for C11R and 3 (33.3%) for A26L. The alignment of the nucleotide sequences of the A26L and A56R fragments revealed that the samples were highly similar to the homologous genes from other Brazilian VACV Group 1 isolates (98.8% identity on average). Furthermore, both the A26L and A56R sequences showed signature deletions also present in the sequences of Group 1 VACV isolates from Brazil. CONCLUSIONS: Our data raises questions about the role of equids in the chain of VACV epidemiology. The surveillance of equids in VACV-affected areas worldwide is relevant.


Assuntos
Surtos de Doenças/veterinária , Equidae , Exantema/veterinária , Doenças da Boca/veterinária , Vaccinia virus/isolamento & purificação , Vacínia/veterinária , Animais , Brasil/epidemiologia , Exantema/patologia , Exantema/virologia , Doenças da Boca/epidemiologia , Doenças da Boca/patologia , Doenças da Boca/virologia , Vacínia/diagnóstico , Vacínia/epidemiologia , Vacínia/patologia
13.
Nat Commun ; 7: 10674, 2016 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-26907725

RESUMO

As atoms and molecules condense to form solids, a crystalline state can emerge with its highly ordered geometry and subnanometric lattice constant. In some physical systems, such as ferroelectric perovskites, a perfect crystalline structure forms even when the condensing substances are non-stoichiometric. The resulting solids have compositional disorder and complex macroscopic properties, such as giant susceptibilities and non-ergodicity. Here, we observe the spontaneous formation of a cubic structure in composite ferroelectric potassium-lithium-tantalate-niobate with micrometric lattice constant, 10(4) times larger than that of the underlying perovskite lattice. The 3D effect is observed in specifically designed samples in which the substitutional mixture varies periodically along one specific crystal axis. Laser propagation indicates a coherent polarization super-crystal that produces an optical X-ray diffractometry, an ordered mesoscopic state of matter with important implications for critical phenomena and applications in miniaturized 3D optical technologies.

14.
Braz J Med Biol Res ; 22(6): 699-701, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2515907

RESUMO

The effect of intracerebrally injected propranolol was measured in the elevated plus-maze, an animal model of anxiety. Microinjection of 10 nmol of propranolol into the dorsal midbrain central gray of the rat increased the percentage of open arm entries, without affecting the total number of arm entries. This selective anxiolytic effect of propranolol was antagonized by 10 nmol of ritanserin, also injected into the dorsal midbrain. The same dose of ritanserin, given alone, did not affect the percentage of open arm entries, though it tended to decrease the total number of entries, an indication of unspecific behavioral depression. Since propranolol is a stereospecific antagonist of presynaptic serotonin (5-HT) autoreceptors and ritanserin is a selective blocker of type 2 5-HT receptors, the present results suggest that the anxiolytic action of propranolol in the midbrain central gray is due to release of endogenous 5-HT acting upon 5-HT2 receptors.


Assuntos
Ansiedade , Comportamento Exploratório/efeitos dos fármacos , Piperidinas/farmacologia , Propranolol/antagonistas & inibidores , Antagonistas da Serotonina/farmacologia , Alternativas aos Testes com Animais , Animais , Injeções Intraventriculares , Masculino , Mesencéfalo/fisiologia , Propranolol/administração & dosagem , Ratos , Ratos Endogâmicos , Ritanserina
15.
Braz J Med Biol Res ; 23(10): 985-7, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2101065

RESUMO

In a previous study we have shown that microinjection of d,1-propranolol into the dorsal midbrain central gray of the rat causes an anxiolytic effect in the elevated plus-maze model which is likely to be mediated by endogenous 5-hydroxytryptamine. In the present experiment, the effects of 1- and d,1-propranolol were compared under the same experimental conditions. Both the 1-isomer and the racemic mixture increased the percentage of open arm entries without affecting the total number of entries into either open or enclosed arms of the maze, thus reproducing the selective anxiolytic effect previously described. The doses of 5 nmol 1-propranolol and 10 nmol d,1-propranolol caused anxiolytic effects of comparable magnitude, while the doses of 2.5 nmol of the former and 5 nmol of the latter were ineffective. Therefore, the 1-isomer was nearly twice as potent as the racemic mixture, thus being responsible for the pharmacological activity observed. These results are compatible with the proposal that propranol blocks stereospecific autoreceptors in serotonergic nerve endings that inhibit neurotransmitter release.


Assuntos
Ansiedade/tratamento farmacológico , Comportamento Exploratório/efeitos dos fármacos , Substância Cinzenta Periaquedutal/fisiologia , Propranolol/farmacologia , Animais , Masculino , Microinjeções , Ratos , Ratos Endogâmicos , Estereoisomerismo
16.
Rev Soc Bras Med Trop ; 30(1): 69-72, 1997.
Artigo em Português | MEDLINE | ID: mdl-9026835

RESUMO

After to characterize the clinic and epidemiological picture of the onchocerciasis in Yanomâmi region, RR, Brazil, begun in 1993, the National Health Foundation (FNS) implemented a Control and Treatment Pilot Project in Tootobi and Balawaú. Here, it was studied skin biopsies from 426 inhabitants. In the nodules of 86.7% from patients was encountered Onchocerca volvulus. The over-all prevalence in the examined population was 66.2%. The treatment with ivermectin covered 80.1% of total population. Adverse reactions, light and moderate, of the medicament were reported in 12.3% of the patients. These results agreeing with the medical literature and suggesting the viability of to increase of the programme for all Yanomâmi area in the next phase.


Assuntos
Antiprotozoários/uso terapêutico , Ivermectina/uso terapêutico , Oncocercose/prevenção & controle , Avaliação de Programas e Projetos de Saúde , Dermatopatias Parasitárias/prevenção & controle , Antiprotozoários/efeitos adversos , Humanos , Ivermectina/efeitos adversos , Projetos Piloto , Prevalência , Saúde da População Rural
17.
Transbound Emerg Dis ; 60(4): 376-7, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22672525

RESUMO

Semen samples from 88 reproductively mature bulls were screened to detect the presence of Brucella spp. by polymerase chain reaction. Twenty-seven samples were found to be positive, underscoring the importance of researching brucellosis in males and the need for greater care in the selection of sperm-donating bulls for semen centres.


Assuntos
Brucella/isolamento & purificação , Brucelose Bovina/diagnóstico , Doenças dos Bovinos/diagnóstico , DNA Bacteriano/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Sêmen/microbiologia , Animais , Brucella/genética , Brucelose Bovina/genética , Bovinos , Doenças dos Bovinos/genética , Doenças dos Bovinos/microbiologia , Masculino , Testes Sorológicos
20.
Braz. j. microbiol ; 44(1): 29-36, 2013. ilus, tab
Artigo em Inglês | LILACS | ID: lil-676882

RESUMO

This study evaluated the influence of the phenolic compounds carvacrol (CAR) and thymol (THY) on some physiological characteristics and on the modulation of the secretion of some staphylococcal virulence factors, that is, coagulase and enterotoxin. This study also investigated possible mechanisms for the establishment of the anti-staphylococcal activity of these compounds. Sublethal concentrations (0.3 and 0.15 µL/mL) of CAR and THY inhibited the activity of the enzymes coagulase and lipase and led to a decrease in salt tolerance. At the tested sublethal concentrations, both CAR and THY led to a total suppression of enterotoxin production. The loss of a 260-nm-absorbing material and an efflux of potassium ions occurred immediately after the addition of CAR and THY at 0.6 and 1.2 µL/mL and increased up to 120 min of exposure. Electron microscopy of cells exposed to CAR and THY (0.6 µL/mL) revealed that individual cells appeared to be deformed, with projections of cellular material. The observations of leakage of cellular material and an altered cell surface suggest that gross damage to a cell's cytoplasmic membrane, which results in a disruption in protein secretion, could be responsible for the anti-staphylococcal properties of CAR and THY.


Assuntos
Humanos , Secreções Corporais , Coagulase/análise , Coagulase/isolamento & purificação , Compostos Fenólicos/análise , Ativação Enzimática , Enterotoxinas/isolamento & purificação , Lipase/análise , Microscopia Eletrônica , Staphylococcus aureus/enzimologia , Staphylococcus aureus/isolamento & purificação , Amostras de Alimentos , Métodos , Virulência
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA