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1.
Braz. j. biol ; 82: e232434, 2022. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1153465

RESUMO

Abstract Many pathogenic strains have acquired multidrug-resistant patterns in recent a year, which poses a major public health concern. The growing need for effective antimicrobial agents as novel therapies against multidrug-resistant pathogens has drawn scientist attention toward nanotechnology. Silver nanoparticles are considered capable of killing multidrug-resistant isolates due to their oligo-dynamic effect on microorganisms. In this research study NPs were synthesized using the gram-positive bacteria Lactobacillus bulgaricus and its activity against selected pathogenic strains. Lactobacillus bulgaricus pure cultures were isolated from raw milk and grown in "De Man, Rogasa, and Sharp" broth for synthesis of nanoparticles. Lactobacillus bulgaricus culture was centrifuged and Cell- free supernatant of it was employed with aqueous silvery ions and evaluated their antibacterial activities against bacterial strains i.e. Staphylococcus aureus, Staphylococcus epidermidis and Salmonella typhi using agar well diffusion assay. Antibiotic profiling against selected pathogenic strains were also conducted using disc diffusion method. The synthesis and characterization of silver nanoparticles were monitored primarily by the conversion of the pale-yellow color of the mixture into a dark-brown color and via ultraviolet-visible absorption spectroscopy and Scanning electron microscopy respectively. The result showed that that AgNPs with size (30.65-100 nm) obtained from Lactobacillus bulgaricus were found to exhibit antibacterial activities against selected bacterial strains. Taken together, these findings suggest that Lactobacillus bulgaricus has great potential for the production of AgNPs with antibacterial activities and highly effective in comparison to tested antibiotics.


Resumo Muitas cepas patogênicas adquiriram padrões multirresistentes nos últimos anos, o que representa um grande problema de saúde pública. A crescente necessidade de agentes antimicrobianos eficazes como novas terapias contra patógenos multirresistentes atraiu a atenção dos cientistas para a nanotecnologia. As nanopartículas de prata são consideradas capazes de matar isolados multirresistentes por causa de seu efeito oligodinâmico em microrganismos. Neste estudo de pesquisa, as NPs foram sintetizadas usando a bactéria Gram-positiva Lactobacillus bulgaricus e sua atividade contra cepas patogênicas selecionadas. Culturas puras de Lactobacillus bulgaricus foram isoladas do leite cru e cultivadas em caldo "De Man, Rogasa e Sharp" para síntese de nanopartículas. A cultura de Lactobacillus bulgaricus foi centrifugada, e o sobrenadante livre de células foi empregado com íons prateados aquosos, avaliando-se suas atividades antibacterianas contra cepas bacterianas, isto é, Staphylococcus aureus, Staphylococcus epidermidis e Salmonella typhi usando ensaio de difusão em poço de ágar. O perfil de antibióticos contra cepas patogênicas selecionadas também foi conduzido usando o método de difusão em disco. A síntese e a caracterização das nanopartículas de prata foram monitoradas principalmente pela conversão da cor amarelo-pálida da mistura em uma cor marrom-escura e por espectroscopia de absorção visível e ultravioleta e por microscopia eletrônica de varredura, respectivamente. O resultado mostrou que AgNPs com tamanho de 30,65-100 nm, obtidas de Lactobacillus bulgaricus, exibiram atividades antibacterianas contra cepas bacterianas selecionadas. Tomados em conjunto, esses achados sugerem que o Lactobacillus bulgaricus tem um grande potencial para a produção de AgNPs com atividades antibacterianas e altamente eficazes em comparação aos antibióticos testados.

2.
Braz J Biol ; 82: e232434, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33681895

RESUMO

Many pathogenic strains have acquired multidrug-resistant patterns in recent a year, which poses a major public health concern. The growing need for effective antimicrobial agents as novel therapies against multidrug-resistant pathogens has drawn scientist attention toward nanotechnology. Silver nanoparticles are considered capable of killing multidrug-resistant isolates due to their oligo-dynamic effect on microorganisms. In this research study NPs were synthesized using the gram-positive bacteria Lactobacillus bulgaricus and its activity against selected pathogenic strains. Lactobacillus bulgaricus pure cultures were isolated from raw milk and grown in "De Man, Rogasa, and Sharp" broth for synthesis of nanoparticles. Lactobacillus bulgaricus culture was centrifuged and Cell- free supernatant of it was employed with aqueous silvery ions and evaluated their antibacterial activities against bacterial strains i.e. Staphylococcus aureus, Staphylococcus epidermidis and Salmonella typhi using agar well diffusion assay. Antibiotic profiling against selected pathogenic strains were also conducted using disc diffusion method. The synthesis and characterization of silver nanoparticles were monitored primarily by the conversion of the pale-yellow color of the mixture into a dark-brown color and via ultraviolet-visible absorption spectroscopy and Scanning electron microscopy respectively. The result showed that that AgNPs with size (30.65-100 nm) obtained from Lactobacillus bulgaricus were found to exhibit antibacterial activities against selected bacterial strains. Taken together, these findings suggest that Lactobacillus bulgaricus has great potential for the production of AgNPs with antibacterial activities and highly effective in comparison to tested antibiotics.


Assuntos
Anti-Infecciosos , Lactobacillus delbrueckii , Nanopartículas Metálicas , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Prata/farmacologia
3.
Clin Exp Dermatol ; 39(5): 646-8, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24934919

RESUMO

The TYR gene (MIM #6069333) is located at position 11q14.3 on the human chromosome, and encodes tyrosinase, which is expressed in melanocytes and controls the biosynthesis of melanin. Most TYR mutations eliminate the activity of tyrosinase, preventing melanocytes from producing any melanin throughout life. People with this form of albinism have white hair, light-coloured eyes and very pale skin. Some mutations in TYR reduce but do not completely eliminate tyrosinase activity, and allow some melanin to be produced. We report a Pakistani family with four members affected by oculocutaneous albinism (OCA). Blood samples were collected from all affected individuals, normal siblings and their parents. Genomic DNA was extracted, and sequence analysis of all the coding exons and adjacent intronic sequences of TYR was performed, which identified a novel missense substitution (p.Ile198Thr). Sequencing of TYR in 90 unrelated healthy individuals showed no sequence variant at this location. Our study expands the mutational spectrum of OCA1.


Assuntos
Albinismo Oculocutâneo/genética , Predisposição Genética para Doença , Monofenol Mono-Oxigenase/genética , Mutação de Sentido Incorreto , Adolescente , Adulto , Grupo com Ancestrais do Continente Asiático/genética , Criança , Pré-Escolar , Análise Mutacional de DNA , Éxons , Feminino , Humanos , Masculino , Linhagem , Adulto Jovem
4.
Chemosphere ; 99: 207-15, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24280053

RESUMO

The present work is focusing on removal of arsenate from aqueous solution using FePO4. The equilibrium study regarding the removal of arsenic by FePO4 was carried out at 298, 308, 318 and 328K. Langmuir parameters were found to increase with the increase in temperature indicating that the adsorption is favorable at high temperature. Kinetic study of arsenate adsorption on FePO4 was also carried out at different temperatures and at pH 6 and 8. Different kinetic models were used to the kinetic data amongst which pseudo second order model was best fitted. The mechanism of the adsorption kinetics was investigated by employing intraparticle diffusion and Richenberg models. The energy of activation (Ea) was found to be 30 and 35.52kJmol(-1) at pH 6 and pH 8, respectively, suggesting chemisorption nature of the adsorption process. The negative entropic values of activation signified the existence of entropy barrier while the positive ΔG(#) values indicated the existence of energy barrier to be crossed over for the occurrence of a chemical reaction. Both the spectroscopic studies and increase in equilibrium pH reveal the anion exchange removal of arsenate from aqueous solution to the solid surface.


Assuntos
Arseniatos/química , Ferro/química , Modelos Químicos , Fosfatos/química , Adsorção , Arsênico/química , Difusão , Concentração de Íons de Hidrogênio , Cinética , Temperatura
5.
Occup Med (Lond) ; 64(1): 39-44, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24265256

RESUMO

BACKGROUND: Using two gloves during surgical procedures is more protective than one in relation to percutaneous needle injuries, but it remains unclear whether the use of two thin-walled gloves is equally as protective as a single thicker-walled glove. AIMS: To compare the volume of contaminant transmitted from fluid-coated solid cutting suture needles through the same thickness of the same glove material made up of differing numbers of layers during simulated needlestick injuries. METHODS: A colorimetric enzyme assay was used to determine the volume of fluid transferred through identical glove materials in mechanized simulated needlestick injuries. The needles were mechanically transferred through varying glove layers [zero (control), one and two] where the cumulative thickness of the double layer was equal to the single thicker layer. The force required to puncture the test mater ials was also recorded. RESULTS: In simulated 'needlestick' injury experiments, significantly less fluid was transmitted through the double, thin glove layer compared with the single thick layer (P < 0.05). The double, thin glove layer transmitted 16% of needle fluid compared with 21% for the single thicker glove layer. Significantly more force was required to puncture the double layer compared with the single thicker layer (P < 0.05), but for any individual puncture there was no association between the puncture force and the volume of fluid transmitted. CONCLUSIONS: A double layer of glove material was more resistant to puncture and removed more enzyme contaminant from a solid cutting suture needle compared with an equivalent single thick layer of glove material.


Assuntos
Acidentes de Trabalho/prevenção & controle , Luvas Cirúrgicas , Técnicas Imunoenzimáticas , Transmissão de Doença Infecciosa do Paciente para o Profissional/prevenção & controle , Ferimentos Penetrantes Produzidos por Agulha/prevenção & controle , Proteínas de Bactérias , Contaminação de Equipamentos , Desenho de Equipamento , Luvas Cirúrgicas/estatística & dados numéricos , Peroxidase do Rábano Silvestre , Humanos , Agulhas , Saúde do Trabalhador
6.
Math Biosci ; 117(1-2): 155-77, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8400572

RESUMO

Fine and Clarkson used a discrete-time epidemic model with variable transmission parameter to analyze measles data for England and Wales for 1950-1965, during the time of biennial epidemics. Their model seems to provide a convincing fit when its parameters are estimated from these data. In particular, they obtained nearly equal estimates for the variable transmission parameter from the widely different data for epidemic and nonepidemic years. They did not, however, study the dynamics of their model. In this paper we make such a study, and find that the model is unsatisfactory in some important respects. It has a unique equilibrium (to be exact, a solution showing only seasonal variation), and neutrally stable oscillations around this equilibrium are possible, but with period approximately 3 years, not 2. (The model also has an exact 3-year cycle, while for intermediate initial values it shows unstable "chaotic" behavior.) If we vary the amount of variation in the transmission parameter, from no variation to 2.5 times the observed amount, the main periodicity remains approximately 3 years, though the complexity of behavior changes, increasing as the amount of variation increases. A continuous-time version of the model also has an equilibrium and a 3-year cycle, the main difference being that these are stable rather than neutrally stable. A stochastic version shows that simulations starting close to either the equilibrium or the 3-year cycle have a high probability of remaining close to the corresponding deterministic solutions for at least 20-30 years. The oscillatory features of the model are thus reasonably robust against stochastic fluctuations. We conclude that the simple homogeneous mixing model cannot be adapted to provide an adequate fit to the data, especially in explaining the observed biennial cycles. It seems likely that the pattern of seasonal variation found by Fine and Clarkson is essentially correct, but for accurate modeling of measles we need also to take into account heterogeneities of mixing in the population, especially those due to age and space.


Assuntos
Sarampo/epidemiologia , Sarampo/transmissão , Periodicidade , Processos Estocásticos , Fatores Etários , Criança , Inglaterra/epidemiologia , Humanos , Incidência , Matemática , Estações do Ano , País de Gales/epidemiologia
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