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  1 / 10211 MEDLINE  
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[PMID]:29458540
[Au] Autor:Li Y; Zhang L; Zhou Y; Zhang Z; Zhang X
[Ad] Endereço:1​Department of Immunology, College of Preclinical Medicine, Southwest Medical University, Luzhou 646000, Sichuan, PR China.
[Ti] Título:Survival of bactericidal antibiotic treatment by tolerant persister cells of Klebsiella pneumoniae.
[So] Source:J Med Microbiol;67(3):273-281, 2018 Mar.
[Is] ISSN:1473-5644
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:PURPOSE: Persister cells, a subpopulation of tolerant cells within the bacterial culture, are commonly thought to be responsible for antibiotic therapy failure and infection recurrence. Klebsiella pneumoniae is a notorious human pathogen for its increasing resistance to antibiotics and wide involvement in severe infections. In this study, we aimed to investigate the persister subpopulation of K. pneumoniae. METHODOLOGY: The presence of persisters in K. pneumoniae was determined by treatment with high concentrations of antibiotics, used alone or in combination. The effect of low level of antibiotics on persister formation was investigated by pre-exposure of cells to antibiotics with low concentrations followed by higher doses. The dependence of persister levels on growth phase was determined by measuring the survival ability of cells along the growth stages upon exposure to a high concentration of antibiotic. Analysis on persister type was carried out by persister elimination assays.Results/Key findings. We show that K. pneumoniae produces high levels of tolerant persister cells to survive treatment by a variety of high concentrations of bactericidal antibiotics and persister formation is prevalent among K. pneumoniae clinical strains. Besides, we find that persister cells can be induced by low concentrations of antibiotics. Finally, we provide evidence that persister formation is growth phase-dependent and Type II persisters dominate the persister subpopulation during the entire exponential phase of K. pneumoniae. CONCLUSION: Our study describes the formation of tolerant persister cells that allow survival of treatment by high concentrations of antibiotics in K. pneumoniae.
[Mh] Termos MeSH primário: Antibacterianos/farmacologia
Klebsiella pneumoniae/efeitos dos fármacos
Klebsiella pneumoniae/fisiologia
Viabilidade Microbiana/efeitos dos fármacos
[Mh] Termos MeSH secundário: Contagem de Colônia Microbiana
Farmacorresistência Bacteriana Múltipla
Tolerância a Medicamentos
Seres Humanos
Infecções por Klebsiella/microbiologia
Klebsiella pneumoniae/crescimento & desenvolvimento
Testes de Sensibilidade Microbiana
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Anti-Bacterial Agents)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180308
[Lr] Data última revisão:
180308
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180221
[St] Status:MEDLINE
[do] DOI:10.1099/jmm.0.000680


  2 / 10211 MEDLINE  
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[PMID]:28461449
[Au] Autor:Stubbendieck RM; Straight PD
[Ad] Endereço:Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, USA.
[Ti] Título:Linearmycins Activate a Two-Component Signaling System Involved in Bacterial Competition and Biofilm Morphology.
[So] Source:J Bacteriol;199(18), 2017 09 15.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Bacteria use two-component signaling systems to adapt and respond to their competitors and changing environments. For instance, competitor bacteria may produce antibiotics and other bioactive metabolites and sequester nutrients. To survive, some species of bacteria escape competition through antibiotic production, biofilm formation, or motility. Specialized metabolite production and biofilm formation are relatively well understood for bacterial species in isolation. How bacteria control these functions when competitors are present is not well studied. To address fundamental questions relating to the competitive mechanisms of different species, we have developed a model system using two species of soil bacteria, and sp. strain Mg1. Using this model, we previously found that linearmycins produced by sp. strain Mg1 cause lysis of cells and degradation of colony matrix. We identified strains of with mutations in the two-component signaling system operon that confer dual phenotypes of specific linearmycin resistance and biofilm morphology. We determined that expression of the ATP-binding cassette (ABC) transporter operon, particularly and , is necessary for biofilm morphology. Using transposon mutagenesis, we identified genes that are required for YfiLMN-mediated biofilm morphology, including several chaperones. Using transcriptional fusions, we found that YfiJ signaling is activated by linearmycins and other polyene metabolites. Finally, using a truncated YfiJ, we show that YfiJ requires its transmembrane domain to activate downstream signaling. Taken together, these results suggest coordinated dual antibiotic resistance and biofilm morphology by a single multifunctional ABC transporter promotes competitive fitness of DNA sequencing approaches have revealed hitherto unexplored diversity of bacterial species in a wide variety of environments that includes the gastrointestinal tract of animals and the rhizosphere of plants. Interactions between different species in bacterial communities have impacts on our health and industry. However, many approaches currently used to study whole bacterial communities do not resolve mechanistic details of interspecies interactions, including how bacteria sense and respond to their competitors. Using a competition model, we have uncovered dual functions for a previously uncharacterized two-component signaling system involved in specific antibiotic resistance and biofilm morphology. Insights gleaned from signaling within interspecies interaction models build a more complete understanding of gene functions important for bacterial communities and will enhance community-level analytical approaches.
[Mh] Termos MeSH primário: Antibacterianos/metabolismo
Antibiose
Bacillus subtilis/fisiologia
Biofilmes/crescimento & desenvolvimento
Viabilidade Microbiana
Streptomyces/fisiologia
[Mh] Termos MeSH secundário: Transportadores de Cassetes de Ligação de ATP/metabolismo
Fusão Gênica Artificial
Bacillus subtilis/efeitos dos fármacos
Elementos de DNA Transponíveis
Perfilação da Expressão Gênica
Regulação Bacteriana da Expressão Gênica
Mutagênese Insercional
Mutação
Transdução de Sinais
Streptomyces/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (ATP-Binding Cassette Transporters); 0 (Anti-Bacterial Agents); 0 (DNA Transposable Elements)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:180306
[Lr] Data última revisão:
180306
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


  3 / 10211 MEDLINE  
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[PMID]:29295973
[Au] Autor:Blaskovich MAT; Hansford KA; Gong Y; Butler MS; Muldoon C; Huang JX; Ramu S; Silva AB; Cheng M; Kavanagh AM; Ziora Z; Premraj R; Lindahl F; Bradford TA; Lee JC; Karoli T; Pelingon R; Edwards DJ; Amado M; Elliott AG; Phetsang W; Daud NH; Deecke JE; Sidjabat HE; Ramaologa S; Zuegg J; Betley JR; Beevers APG; Smith RAG; Roberts JA; Paterson DL; Cooper MA
[Ad] Endereço:Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, 4072, Australia. m.blaskovich@uq.edu.au.
[Ti] Título:Protein-inspired antibiotics active against vancomycin- and daptomycin-resistant bacteria.
[So] Source:Nat Commun;9(1):22, 2018 01 02.
[Is] ISSN:2041-1723
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The public health threat posed by a looming 'post-antibiotic' era necessitates new approaches to antibiotic discovery. Drug development has typically avoided exploitation of membrane-binding properties, in contrast to nature's control of biological pathways via modulation of membrane-associated proteins and membrane lipid composition. Here, we describe the rejuvenation of the glycopeptide antibiotic vancomycin via selective targeting of bacterial membranes. Peptide libraries based on positively charged electrostatic effector sequences are ligated to N-terminal lipophilic membrane-insertive elements and then conjugated to vancomycin. These modified lipoglycopeptides, the 'vancapticins', possess enhanced membrane affinity and activity against methicillin-resistant Staphylococcus aureus (MRSA) and other Gram-positive bacteria, and retain activity against glycopeptide-resistant strains. Optimised antibiotics show in vivo efficacy in multiple models of bacterial infection. This membrane-targeting strategy has potential to 'revitalise' antibiotics that have lost effectiveness against recalcitrant bacteria, or enhance the activity of other intravenous-administered drugs that target membrane-associated receptors.
[Mh] Termos MeSH primário: Antibacterianos/farmacologia
Bactérias/efeitos dos fármacos
Daptomicina/farmacologia
Farmacorresistência Bacteriana/efeitos dos fármacos
Proteínas de Membrana/metabolismo
Vancomicina/farmacologia
[Mh] Termos MeSH secundário: Animais
Antibacterianos/metabolismo
Antibacterianos/farmacocinética
Bactérias/classificação
Sobrevivência Celular/efeitos dos fármacos
Glicopeptídeos/metabolismo
Células HEK293
Células Hep G2
Seres Humanos
Masculino
Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos
Camundongos
Testes de Sensibilidade Microbiana
Viabilidade Microbiana/efeitos dos fármacos
Staphylococcus aureus/efeitos dos fármacos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Anti-Bacterial Agents); 0 (Glycopeptides); 0 (Membrane Proteins); 6Q205EH1VU (Vancomycin); NWQ5N31VKK (Daptomycin)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180305
[Lr] Data última revisão:
180305
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180104
[St] Status:MEDLINE
[do] DOI:10.1038/s41467-017-02123-w


  4 / 10211 MEDLINE  
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[PMID]:28748404
[Au] Autor:Scariot FJ; Jahn L; Delamare APL; Echeverrigaray S
[Ad] Endereço:Institute of Biotechnology, University of Caxias do Sul, Caxias do Sul, Rio Grande Do Sul, Brazil.
[Ti] Título:Necrotic and apoptotic cell death induced by Captan on Saccharomyces cerevisiae.
[So] Source:World J Microbiol Biotechnol;33(8):159, 2017 Aug.
[Is] ISSN:1573-0972
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Captan is one of the most widely used broad-spectrum fungicide applied to control several early and late diseases of grapes, apples, and other fruits and vegetables, and as other phthalimide fungicides is defined as a multisite compound with thiol-reactivity. Captan can affect non-target organisms as yeasts, modifying microbial populations and fermentation processes. In this study, we asked whether Captan thiol-reactivity and other mechanisms are involved in acute Captan-induced cell death on aerobic growing Saccharomyces cerevisiae. Thus for, we analyze cellular protein and non-protein thiols, cell membrane integrity, reactive oxygen species accumulation, phosphatidylserine externalization, and apoptotic mutants behavior. The results showed that when submitted to acute Captan treatment most cells lost their membrane integrity and died by necrosis due to Captan reaction with thiols. However, part of the cells, even maintaining their membrane integrity, lost their culture ability. These cells showed an apoptotic behavior that may be the result of non-protein thiol depletion and consequent increase of reactive oxygen species (ROS). ROS accumulation triggers a metacaspase-dependent apoptotic cascade, as shown by the higher viability of the yca1-deleted mutant. Together, necrosis and apoptosis are responsible for the high mortality detected after acute Captan treatment of aerobically growing cells of S. cerevisiae.
[Mh] Termos MeSH primário: Apoptose/efeitos dos fármacos
Captana/farmacologia
Morte Celular/efeitos dos fármacos
Saccharomyces cerevisiae/efeitos dos fármacos
[Mh] Termos MeSH secundário: Membrana Celular/efeitos dos fármacos
Fermentação
Fungicidas Industriais/farmacologia
Viabilidade Microbiana/efeitos dos fármacos
Mutação
Necrose
Espécies Reativas de Oxigênio/metabolismo
Saccharomyces cerevisiae/genética
Saccharomyces cerevisiae/crescimento & desenvolvimento
Proteínas de Saccharomyces cerevisiae/genética
Proteínas de Saccharomyces cerevisiae/metabolismo
Compostos de Sulfidrila/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Fungicides, Industrial); 0 (Reactive Oxygen Species); 0 (Saccharomyces cerevisiae Proteins); 0 (Sulfhydryl Compounds); EOL5G26Q9F (Captan)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180305
[Lr] Data última revisão:
180305
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170728
[St] Status:MEDLINE
[do] DOI:10.1007/s11274-017-2325-3


  5 / 10211 MEDLINE  
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[PMID]:29073460
[Au] Autor:Scariot MC; Venturelli GL; Prudêncio ES; Arisi ACM
[Ad] Endereço:CAL CCA UFSC, Food Science and Technology Department, Federal University of Santa Catarina, Rod. Admar Gonzaga, 1346, 88034-001 Florianópolis, SC, Brazil.
[Ti] Título:Quantification of Lactobacillus paracasei viable cells in probiotic yoghurt by propidium monoazide combined with quantitative PCR.
[So] Source:Int J Food Microbiol;264:1-7, 2018 Jan 02.
[Is] ISSN:1879-3460
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Propidium monoazide (PMA) coupled with qPCR has been successfully used for specific quantification of viable bacteria cells in diverse matrices food. The present study aimed to develop PMA-qPCR assay for quantification of Lactobacillus paracasei viable cells in probiotic yoghurt. L. paracasei grown in culture medium was submitted to heat treatment at 60°C for different periods of time and probiotic yoghurt containing L. paracasei were prepared and stored at 4°C for 30days. The viable cells were quantified using qPCR and PMA-qPCR assays targeting tuf gene and also by plate counting. Standard curves were prepared and mean efficiency obtained was 94% and 96% (R >0.98) to L. paracasei in culture medium and probiotic yoghurt stored one day, respectively. The limit of detection (LOD) for both samples was 10 genome copies, corresponding to 32.1pg of DNA. For viable cells quantification, standard curves Cq versus log CFU were plotted using mean CFU by plate counting of L. paracasei grown in culture medium and probiotic yoghurt. Results obtained for L. paracasei heat-treated cells were concordant by PMA-qPCR and plate count, CFU decreased as the heat treatment time increased, while qPCR count remained constant. L. paracasei enumerations obtained by qPCR for probiotic yoghurt stored one day and 30days were higher than enumerations by PMA-qPCR for the same samples. The plate count values were similar to CFU values obtained by PMA-qPCR. These results showed that PMA-qPCR is a powerful approach compared with culture-dependent methods for quantification of L. paracasei viable cells in yoghurt. PMA-qPCR allowed reliable obtained results much faster than plate counting.
[Mh] Termos MeSH primário: Azidas/química
Carga Bacteriana/métodos
Lactobacillus paracasei/crescimento & desenvolvimento
Propídio/análogos & derivados
Reação em Cadeia da Polimerase em Tempo Real/métodos
Iogurte/microbiologia
[Mh] Termos MeSH secundário: DNA Bacteriano/análise
Temperatura Alta
Viabilidade Microbiana
Probióticos/análise
Propídio/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Azides); 0 (DNA, Bacterial); 0 (propidium monoazide); 36015-30-2 (Propidium)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171027
[St] Status:MEDLINE


  6 / 10211 MEDLINE  
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[PMID]:29353702
[Au] Autor:Manoil D; Lange N; Bouillaguet S
[Ad] Endereço:Endodontics Unit, Section of Dental Medicine, University of Geneva, 1, rue Michel-Servet, CH-1206 Geneva, Switzerland. Electronic address: Daniel.Manoil@unige.ch.
[Ti] Título:Enzyme-mediated photoinactivation of Enterococcus faecalis using Rose Bengal-acetate.
[So] Source:J Photochem Photobiol B;179:84-90, 2018 Feb.
[Is] ISSN:1873-2682
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:Rose Bengal-acetate (RB-Ac) is a pro-photosensitizer claimed to diffuse into target cells, where the acetate groups are hydrolyzed and the photosensitizing properties of Rose Bengal (RB) are restored. Despite promising results on tumor cells, the interaction of RB-Ac with bacteria has never been investigated. This study aimed to assess the interaction of RB-Ac with Enterococcus faecalis and to evaluate its potential use in antimicrobial photodynamic therapy (aPDT). Spectrofluorometry was used to assess the ability of E. faecalis to hydrolyze the RB-Ac compound. Fluorescence microscopy was employed to observe the distribution and to evaluate the cellular uptake of the RB produced. The antibacterial efficiency of RB-Ac-mediated aPDT was assessed by flow cytometry in combination with the LIVE/DEAD® staining. Results showed that RB-Ac was successfully hydrolyzed in the presence of E. faecalis cells. The RB produced appeared to incorporate the membrane of bacteria. Higher concentrations of RB-Ac resulted in higher incorporation of RB. The blue-light irradiation of RB-Ac-treated samples significantly reduced bacterial viability. Less than 0.01% of E. faecalis survived after incubation with 200 µM RB-Ac during 900 min and blue-light activation. The current report indicates that E. faecalis cells can hydrolyze the RB-Ac compound to produce active RB. The use of RB-Ac did not appear to allow cytoplasmic internalization of the RB produced, which rather incorporated the membrane bilayers of E. faecalis. The use of RB-Ac did not provide additional advantages over RB in terms of PS localization. Nonetheless, sufficient RB was produced and incorporated into the membranes of bacteria to elicit effective aPDT.
[Mh] Termos MeSH primário: Enterococcus faecalis/efeitos dos fármacos
Fármacos Fotossensibilizantes/farmacologia
Rosa Bengala/análogos & derivados
[Mh] Termos MeSH secundário: Enterococcus faecalis/efeitos da radiação
Hidrólise/efeitos da radiação
Luz
Viabilidade Microbiana/efeitos dos fármacos
Viabilidade Microbiana/efeitos da radiação
Microscopia de Fluorescência
Rosa Bengala/farmacologia
Espectrometria de Fluorescência
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Photosensitizing Agents); 0 (Rose Bengal acetate); 1ZPG1ELY14 (Rose Bengal)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180223
[Lr] Data última revisão:
180223
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180123
[St] Status:MEDLINE


  7 / 10211 MEDLINE  
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[PMID]:28457835
[Au] Autor:Tetz G; Cynamon M; Hendricks G; Vikina D; Tetz V
[Ad] Endereço:TGV-inhalonix, 303 5th Avenue #2012, New York, NY 10016, USA. Electronic address: tets@tgvlabs.com.
[Ti] Título:In vitro activity of a novel compound, Mul-1867, against clinically significant fungi Candida spp. and Aspergillus spp.
[So] Source:Int J Antimicrob Agents;50(1):47-54, 2017 Jul.
[Is] ISSN:1872-7913
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:There is an urgent need for new antifungal compounds to treat various types of fungal infections, including pulmonary infections. This study was designed to investigate the potency of a novel compound (Mul-1867) against Candida spp. and Aspergillus spp. isolated from patients with fungal pneumonia, cystic fibrosis and chronic obstructive pulmonary disease. Mul-1867 was highly effective against susceptible control strains as well as resistant clinical isolates, with minimum fungicidal concentrations (MFCs) varying from 0.06 µg/mL to 0.5 µg/mL. It was also highly effective against pre-formed 48-h-old biofilms formed by yeasts and moulds. The half-minimal biofilm eradication concentration (MBEC ) was equal to the MFC. The minimum biofilm eradication concentration to eliminate 90% of biofilms (MBEC ) varied from 1 × to 4 × MFC. Scanning electron microscopy revealed morphological changes accompanied by the release of intracellular material from the fungal cells following exposure to Mul-1867. Furthermore, an increased concentration of nucleic acids was found in the medium after 5 min and 20 min of Mul-1867 treatment, indicating leakage of cytoplasmic contents. Overall, these data indicate that Mul-1867 may be a promising inhaled antifungal agent for the treatment and prevention of fungal respiratory infections.
[Mh] Termos MeSH primário: Antifúngicos/farmacologia
Aspergillus/efeitos dos fármacos
Candida/efeitos dos fármacos
[Mh] Termos MeSH secundário: Aspergilose/microbiologia
Aspergillus/isolamento & purificação
Aspergillus/fisiologia
Biofilmes/efeitos dos fármacos
Candida/isolamento & purificação
Candida/fisiologia
Candidíase/microbiologia
Meios de Cultura/química
DNA Fúngico/análise
Seres Humanos
Testes de Sensibilidade Microbiana
Viabilidade Microbiana/efeitos dos fármacos
Microscopia Eletrônica de Varredura
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antifungal Agents); 0 (Culture Media); 0 (DNA, Fungal)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180222
[Lr] Data última revisão:
180222
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170502
[St] Status:MEDLINE


  8 / 10211 MEDLINE  
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[PMID]:29326041
[Au] Autor:Xiao C; Yu Q; Zhang B; Li J; Zhang D; Li M
[Ad] Endereço:Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
[Ti] Título:Role of the mRNA export factor Sus1 in oxidative stress tolerance in Candida albicans.
[So] Source:Biochem Biophys Res Commun;496(2):253-259, 2018 02 05.
[Is] ISSN:1090-2104
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:In eukaryotes, the nuclear export of mRNAs is essential for gene expression. However, little is known about the role of mRNA nuclear export in the important fungal pathogen, Candida albicans. In this study, we identified C. albicans Sus1, a nucleus-localized protein that is required for mRNA export. Interestingly, the sus1Δ/Δ displayed hyper-sensitivity to extracellular oxidative stress, enhanced ROS accumulation and severe oxidative stress-related cell death. More strikingly, although the mutant exhibited normal activation of the expression of oxidative stress response (OSR) genes, it had attenuated activity of ROS scavenging system, which may be attributed to the defect in OSR mRNA export in this mutant. In addition, the virulence of the sus1Δ/Δ was seriously attenuated. Taken together, our findings provide evidence that the mRNA export factor Sus1 plays an important role in oxidative stress tolerance and pathogenesis.
[Mh] Termos MeSH primário: Candida albicans/genética
Candida albicans/patogenicidade
Regulação Fúngica da Expressão Gênica
Proteínas Nucleares/genética
Estresse Oxidativo/genética
Proteínas de Ligação a RNA/genética
[Mh] Termos MeSH secundário: Transporte Ativo do Núcleo Celular
Candida albicans/metabolismo
Núcleo Celular/metabolismo
Deleção de Genes
Viabilidade Microbiana
Proteínas Nucleares/metabolismo
RNA Mensageiro/genética
RNA Mensageiro/metabolismo
Proteínas de Ligação a RNA/metabolismo
Espécies Reativas de Oxigênio/metabolismo
Estresse Fisiológico
Virulência
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Nuclear Proteins); 0 (RNA, Messenger); 0 (RNA-Binding Proteins); 0 (Reactive Oxygen Species)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180214
[Lr] Data última revisão:
180214
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180113
[St] Status:MEDLINE


  9 / 10211 MEDLINE  
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[PMID]:28741960
[Au] Autor:Beuchat LR; Mann DA; Kelly CA; Ortega YR
[Ad] Endereço:Center for Food Safety and Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, Georgia 30223-1797, USA.
[Ti] Título:Retention of Viability of Salmonella in Sucrose as Affected by Type of Inoculum, Water Activity, and Storage Temperature.
[So] Source:J Food Prot;80(9):1408-1414, 2017 09.
[Is] ISSN:1944-9097
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Outbreaks of salmonellosis have been associated with consumption of high-sugar, low-water activity (a ) foods. The study reported here was focused on determining the effect of storage temperature (5 and 25°C) on survival of initially high and low levels of Salmonella in dry-inoculated sucrose (a 0.26 ± 0.01 to 0.54 ± 0.01) and wet-inoculated sucrose (a 0.24 ± 0.01 to 0.44 ± 0.04) over a 52-week period. With the exception of dry-inoculated sucrose at a 0.26, Salmonella survived for 52 weeks in dry- and wet-inoculated sucrose stored at 5 and 25°C. Retention of viability was clearly favored in sucrose stored at 5°C compared with 25°C, regardless of level or type of inoculum or a . Survival at 5°C was not affected by a . Initial high-inoculum counts of 5.18 and 5.25 log CFU/g of dry-inoculated sucrose (a 0.26 and 0.54, respectively) stored for 52 weeks at 5°C decreased by 0.56 and 0.53 log CFU/g; counts decreased by >4.18 and >4.25 log CFU/g in samples stored at 25°C. Inactivation rates in wet-inoculated sucrose were similar to those in dry-inoculated sucrose; however, a trend toward higher persistence of Salmonella in dry- versus wet-inoculated sucrose suggests there was a higher proportion of cells in the wet inoculum with low tolerance to osmotic stress. Survival patterns were similar in sucrose initially containing a low level of Salmonella (2.26 to 2.91 log CFU/g). The pathogen was recovered from low-inoculated sucrose stored at 5°C for 52 weeks regardless of type of inoculum or a and from dry-inoculated sucrose (a 0.54) and wet-inoculated sucrose (a 0.24) stored at 25°C for 12 and 26 weeks, respectively. Results emphasize the importance of preventing contamination of sucrose intended for use as an ingredient in foods not subjected to a treatment that would be lethal to Salmonella.
[Mh] Termos MeSH primário: Manipulação de Alimentos/métodos
Viabilidade Microbiana
Salmonella/crescimento & desenvolvimento
Sacarose
[Mh] Termos MeSH secundário: Contagem de Colônia Microbiana
Microbiologia de Alimentos
Temperatura Ambiente
Água
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
059QF0KO0R (Water); 57-50-1 (Sucrose)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:180214
[Lr] Data última revisão:
180214
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170726
[St] Status:MEDLINE
[do] DOI:10.4315/0362-028X.JFP-16-537


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[PMID]:29241319
[Au] Autor:Chen H; Huang J; Shi X; Li Y; Liu Y
[Ad] Endereço:School of Food and Biological Engineering, Shaanxi University of Science and Technology Xi?an,China.
[Ti] Título:Effects of six substances on the growth and freeze-drying of Lactobacillus delbrueckii subsp. bulgaricus.
[So] Source:Acta Sci Pol Technol Aliment;16(4):403-412, 2017 Oct-Dec.
[Is] ISSN:1898-9594
[Cp] País de publicação:Poland
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: The efficacy of Lactobacillus delbrueckii subsp. bulgaricus as starter cultures for the dairy industry depends largely on the number of viable and active cells. Freeze-drying is the most convenient and successful method to preserve the bacterial cells. However, not all strains survived during freeze-drying. METHODS: The effects of six substances including NaCl, sorbitol, mannitol, mannose, sodium glutamate, betaine added to the MRS medium on the growth and freeze-drying survival rate and viable counts of Lb. delbrueckii subsp. bulgaricus were studied through a single-factor test and Plackett-Burman design. Subsequently, the optimum freeze-drying conditions of Lb. delbrueckii subsp. bulgaricus were determined. RESULTS: Lb. delbrueckii subsp. bulgaricus survival rates were up to the maximum of 42.7%, 45.4%, 23.6%, while the concentrations of NaCl, sorbitol, sodium glutamate were 0.6%, 0.15%, 0.09%, respectively. In the optimum concentration, the viable counts in broth is 6.1, 6.9, 5.13 (×108 CFU/mL), respectively; the viable counts in freeze-drying power are 3.09, 5.2, 2.7 (×1010 CFU/g), respectively. CONCLUSIONS: Three antifreeze factors including NaCl, sorbitol, sodium glutamate have a positive effect on the growth and freeze-drying of Lb. delbrueckii subsp. bulgaricus. The results are beneficial for developing Lb. delbrueckii subsp. bulgaricus.
[Mh] Termos MeSH primário: Crioprotetores/farmacologia
Aditivos Alimentares/farmacologia
Liofilização
Lactobacillus delbrueckii
[Mh] Termos MeSH secundário: Betaína/farmacologia
Lactobacillus delbrueckii/efeitos dos fármacos
Lactobacillus delbrueckii/crescimento & desenvolvimento
Manitol/farmacologia
Viabilidade Microbiana
Cloreto de Sódio/farmacologia
Glutamato de Sódio/farmacologia
Sorbitol/farmacologia
Iogurte/microbiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Cryoprotective Agents); 0 (Food Additives); 3OWL53L36A (Mannitol); 3SCV180C9W (Betaine); 451W47IQ8X (Sodium Chloride); 506T60A25R (Sorbitol); W81N5U6R6U (Sodium Glutamate)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180208
[Lr] Data última revisão:
180208
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171216
[St] Status:MEDLINE
[do] DOI:10.17306/J.AFS.0512



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