Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 36
Filtrar
1.
BMC Genomics ; 24(1): 680, 2023 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-37957547

RESUMO

BACKGROUND: In dairy cows, diet is one factor that can affect their milk production and composition. However, the effect of feed restriction on milk miRNome has not yet been described. Indeed, milk is the body fluid with the highest RNA concentration, which includes numerous microRNA. Its presence in the four different milk fractions, whole milk, fat globules, mammary epithelial cells and extracellular vesicles, is still poorly documented. This study aimed to describe the effects of different feed restrictions on the miRNome composition of different milk fractions. RESULTS: Two feed restrictions were applied to lactating dairy cows, one of high intensity and one of moderate intensity. 2,896 mature microRNA were identified in the different milk fractions studied, including 1,493 that were already known in the bovine species. Among the 1,096 microRNA that were sufficiently abundant to be informative, the abundance of 1,027 of them varied between fractions: 36 of those were exclusive to one milk fraction. Feed restriction affected the abundance of 155 microRNA, with whole milk and milk extracellular vesicles being the most affected, whereas milk fat globules and exfoliated mammary epithelial cells were little or not affected at all. The high intensity feed restriction led to more microRNA variations in milk than moderate restriction. The target prediction of known microRNA that varied under feed restriction suggested the modification of some key pathways for lactation related to milk fat and protein metabolisms, cell cycle, and stress responses. CONCLUSIONS: This study highlighted that the miRNome of each milk fraction is specific, with mostly the same microRNA composition but with variations in abundance between fractions. These specific miRNomes were affected differently by feed restrictions, the intensity of which appeared to be a major factor modulating milk miRNomes. These findings offer opportunities for future research on the use of milk miRNA as biomarkers of energy status in dairy cows, which is affected by feed restrictions.


Assuntos
Líquidos Corporais , MicroRNAs , Feminino , Bovinos , Animais , Lactação , Leite/metabolismo , Dieta/veterinária , MicroRNAs/genética , MicroRNAs/metabolismo , Ração Animal/análise
2.
Sci Rep ; 12(1): 18886, 2022 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-36344510

RESUMO

Milk production in dairy cows is affected by numerous factors, including diet. Feed restriction is known to have little impact on milk total protein content but its effect on the fine protein composition is still poorly documented. The objective of this study was to describe the effects of two feed restriction trials of different intensities on the milk protein composition of Holstein cows. One restriction trial was of high intensity (H: 8 mid-lactation Holstein cows) and the second of moderate intensity (M: 19 peak lactation Holstein cows). Feed restriction decreased the milk protein yield for caseins under the M trial and of all six major milk proteins under the H trial. These decreased yields lead to lower concentrations of αs1-, αs2- and ß-caseins during the H trial. The milk proteome, analyzed on 32 milk samples, was affected as a function of restriction intensity. Among the 345 proteins identified eight varied under the M trial and 160 under the H trial. Ontology analyses revealed their implication in carbohydrate, lipid and protein metabolisms as well as in the immune system. These proteins reflected adaptations of the animal and mammary gland physiology to feed restriction and constituted a signature of this change.


Assuntos
Lactação , Proteínas do Leite , Animais , Bovinos , Feminino , Ração Animal/análise , Caseínas/metabolismo , Dieta/veterinária , Lactação/fisiologia , Leite/química , Proteínas do Leite/metabolismo
3.
Sci Rep ; 9(1): 20345, 2019 12 30.
Artigo em Inglês | MEDLINE | ID: mdl-31889100

RESUMO

The concept of milk as a healthy food has opened the way for studies on milk components, from nutrients to microRNAs, molecules with broad regulatory properties present in large quantities in milk. Characterization of these components has been performed in several species, such as humans and bovine, depending on the stages of lactation. Here, we have studied the variation in milk microRNA composition according to genetic background. Using high throughput sequencing, we have characterized and compared the milk miRNomes of Holstein and Normande cattle, dairy breeds with distinct milk production features, in order to highlight microRNAs that are essential for regulation of the lactation process. In Holstein and Normande milk, 2,038 and 2,030 microRNAs were identified, respectively, with 1,771 common microRNAs, of which 1,049 were annotated and 722 were predicted. The comparison of the milk miRNomes of two breeds allowed to highlight 182 microRNAs displaying significant differences in the abundance. They are involved in the regulation of lipid metabolism and mammary morphogenesis and development, which affects lactation. Our results provide new insights into the regulation of molecular mechanisms involved in milk production.


Assuntos
MicroRNAs , Leite , Transcriptoma , Fatores Etários , Animais , Cruzamento , Bovinos , Biologia Computacional/métodos , Patrimônio Genético , Sequenciamento de Nucleotídeos em Larga Escala , Leite/metabolismo , Especificidade da Espécie
4.
Food Res Int ; 108: 558-570, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29735091

RESUMO

Tap water is used in France to reconstitute powder infant formula, although it is not sterile and possibly contaminated by microbiological and chemical hazards. The present study aims to quantify risks of using tap water in France for the preparation of infant formula, during the first six months of life. Cryptosporidium and arsenic were selected as hazards of greatest concern in microbiology and chemistry, respectively. A probabilistic model was developed using French (when available) and European (alternatively) data. Second order Monte Carlo simulation was used to separate uncertainty and variability of inputs. Outputs were expressed at the individual level as probability of illness and at the population level, using a common metric, the DALY (Disability Adjusted Life Year). Two scenarios of milk preparation were considered: with un-boiled or boiled tap water. Consuming infant formula rehydrated with un-boiled tap water during the first six months of life led to a total of 2250 DALYs per 100,000 infants (90% uncertainty interval [960; 7650]) for Cryptosporidium due to diarrhea, and 1 DALY [0.4; 2] for arsenic due to expected lifetime risk of lung and bladder cancer as a result of early exposure in life. For the entire population, boiling water would suppress the risk from Cryptosporidium. In contrast, the incremental cancer risk was low at the population level but elevated for 5% of the population exposed to high levels of arsenic. A stringent monitoring of tap water supply points should be continued. This multi-risk assessment model could help public health authorities and managers in evaluating both microbiological and chemical safety issues associated with using infant formula prepared with tap water.


Assuntos
Arsênio/análise , Cryptosporidium/isolamento & purificação , Água Potável/parasitologia , Fórmulas Infantis , Poluentes Químicos da Água/análise , Abastecimento de Água , Fatores Etários , Arsênio/efeitos adversos , Alimentação com Mamadeira , Criptosporidiose/epidemiologia , Criptosporidiose/parasitologia , Diarreia/epidemiologia , Diarreia/parasitologia , Feminino , França/epidemiologia , Humanos , Lactente , Recém-Nascido , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/epidemiologia , Masculino , Método de Monte Carlo , Medição de Risco , Fatores de Risco , Fatores de Tempo , Neoplasias da Bexiga Urinária/induzido quimicamente , Neoplasias da Bexiga Urinária/epidemiologia , Poluentes Químicos da Água/efeitos adversos
5.
Int J Cardiol ; 259: 40-42, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29486997

RESUMO

Out of 163 STEMI patients, 33 presented left ventricular remodeling (LVR) as assessed by multiple cardiac magnetic resonance (CMR) scans. LVR patients were identified as EarlyLVR (LVR occurring between baseline and 3 months) or LateLVR (LVR occurring between 3 months and one year), and matched to non-remodeler patients in term of age, gender, anterior infarction, baseline LV ejection fraction and infarct size. ST2 and NT-proBNP were measured at baseline and 3 months. Systolic wall stress (SWS) was calculated by CMR. At baseline, mean levels of ST2, NT-proBNP and SWS were 67.1 ±â€¯54.1 ng/mL, 1529 ±â€¯1702 ng/L and 17.9 ±â€¯7.1 103 N·m-2, respectively, and did not differ among the groups. At 3 months, EarlyLVR patients presented significant higher ST2, NT-proBNP and SWS (31.6 ±â€¯12.7 ng/mL, 1142 ±â€¯1069 ng/L, 25.5 ±â€¯9.7 103 N·m-2), compared to the corresponding non-remodelers (20.5 ±â€¯8.6 ng/mL, 397 ±â€¯273 ng/L, 18 ±â€¯7.3 103 N·m-2; with p = 0.017, 0.040, and 0.036, respectively). LateLVR patients presented higher ST2 at 3 months than their non-remodelers (33.6 ±â€¯15.9 versus 23.66 ±â€¯8.7 ng/mL, p = 0.046), while NT-proBNP and SWS were not different between groups at both timepoints.


Assuntos
Proteína 1 Semelhante a Receptor de Interleucina-1/sangue , Infarto do Miocárdio com Supradesnível do Segmento ST/sangue , Infarto do Miocárdio com Supradesnível do Segmento ST/diagnóstico por imagem , Remodelação Ventricular/fisiologia , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Fatores de Tempo
6.
Food Chem Toxicol ; 109(Pt 1): 230-236, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28888734

RESUMO

The container, also known as primary package or inner package, could be defined as the packaging designed to come into direct contact with the cosmetic product. To author's knowledge, no study was available regarding the effect of the primary package on the consumption of cosmetic products. The aim of the study was to assess the impact of the container on the consumption of three cosmetic products widely used, i.e. shampoo, shower gel and emollient cream. The three products were contained in a tube with a flip top cap and in a bottle with a pump. The study was conducted on 221 French adults: 108 women and 113 men. Results showed that the consumption of each cosmetic product was slightly higher when the product was packaged in tube with a flip top cap than in bottle with a pump. The difference of consumption could vary from 5 % to 23 % when calculated with mean values. This information could be interesting for safety evaluators, safety agencies and commercial services of cosmetic manufacturers.


Assuntos
Cosméticos/toxicidade , Adulto , Qualidade de Produtos para o Consumidor , Cosméticos/metabolismo , Feminino , França , Humanos , Masculino , Medição de Risco , Adulto Jovem
7.
Int J Food Microbiol ; 233: 60-72, 2016 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-27343425

RESUMO

A multi-criteria framework combining safety, hygiene and sensorial quality was developed to investigate the possibility of extending the shelf-life and/or removing lactate by applying High Hydrostatic Pressure (HHP) in a ready-to-cook (RTC) poultry product. For this purpose, Salmonella and Listeria monocytogenes were considered as safety indicators and Escherichia coli as hygienic indicator. Predictive modeling was used to determine the influence of HHP and lactate concentration on microbial growth and survival of these indicators. To that end, probabilistic assessment exposure models developed in a previous study (Lerasle, M., Guillou, S., Simonin, H., Anthoine, V., Chéret, R., Federighi, M., Membré, J.M. 2014. Assessment of Salmonella and L. monocytogenes level in ready-to-cook poultry meat: Effect of various high pressure treatments and potassium lactate concentrations. International Journal of Food Microbiology 186, 74-83) were used for L. monocytogenes and Salmonella. Besides, for E. coli, an exposure assessment model was built by modeling data from challenge-test experiments. Finally, sensory tests and color measurements were performed to evaluate the effect of HHP on the organoleptic quality of an RTC product. Quantitative rules of decision based on safety, hygienic and organoleptic criteria were set. Hygienic and safety criteria were associated with probability to exceed maximum contamination levels of L. monocytogenes, Salmonella and E. coli at the end of the shelf-life whereas organoleptic criteria corresponded to absence of statistical difference between pressurized and unpressurized products. A tradeoff between safety and hygienic risk, color and taste, was then applied to define process and formulation enabling shelf-life extension. In the resulting operating window, one condition was experimentally assayed on naturally contaminated RTC products to validate the multi-criteria approach. As a conclusion, the framework was validated; it was possible to extend the shelf-life of an RTC poultry product containing 1.8% (w/w) lactate by one week, despite slight color alteration. This approach could be profitably implemented by food processors as a decision support tool for shelf-life determination.


Assuntos
Conservação de Alimentos/métodos , Produtos da Carne/microbiologia , Produtos Avícolas/microbiologia , Animais , Qualidade de Produtos para o Consumidor , Culinária , Escherichia coli/crescimento & desenvolvimento , Conservação de Alimentos/instrumentação , Armazenamento de Alimentos , Humanos , Pressão Hidrostática , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Aves Domésticas , Salmonella/crescimento & desenvolvimento , Paladar
8.
Thromb Res ; 141: 98-103, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26994471

RESUMO

INTRODUCTION: Fondaparinux (FDX) was demonstrated to be cardioprotective in a rat model of myocardial ischemia reperfusion. In this model, FDX reduced infarct size after 2h of reperfusion, involving the activation of the survivor activating factor enhancement (SAFE) pathway as early as 30min post-reperfusion. Our aim was to study if this cardioprotection could be explained by anti-inflammatory mechanisms and a protective effect on vessels. METHODS: Wistar male rats were subjected to 40minutes (min) of myocardial ischemia, followed by 30min or 2h of reperfusion. Rats were randomized into four groups: control 30min (n=7), FDX 30min (n=7), control 2h (n=7), and FDX 2h (n=7). The FDX groups received 10mg/kg injection of FDX 10min prior to initiating reperfusion. We studied: 1) mRNA expression of endothelial markers, such as thrombomodulin (TM), endothelial protein C receptor (EPCR), and tissue factor (TF) and 2) proteic expression of ICAM-1, NF-κB, IκB, and JNK. Leukocyte infiltration was assessed by histochemistry. We also evaluated TM and EPCR mRNA expression in a model of isolated rat mesenteric arteries incubated with FDX. RESULTS: FDX upregulated the expression of TM and EPCR mRNA in the models of myocardial infarction and isolated mesenteric arteries. No difference was observed between the treated and control groups regarding the expression of pro-inflammatory signaling proteins, adhesion molecules, and leukocyte infiltration after 2h of reperfusion. CONCLUSION: The cardioprotective effect of FDX at early-stage reperfusion could be related to vascular protection, yet not to an anti-inflammatory effect.


Assuntos
Anticoagulantes/uso terapêutico , Cardiotônicos/uso terapêutico , Infarto do Miocárdio/tratamento farmacológico , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Polissacarídeos/uso terapêutico , Receptores de Endotelina/genética , Trombomodulina/genética , Animais , Modelos Animais de Doenças , Fondaparinux , Masculino , Artérias Mesentéricas/efeitos dos fármacos , Artérias Mesentéricas/metabolismo , Artérias Mesentéricas/patologia , Infarto do Miocárdio/genética , Infarto do Miocárdio/patologia , Traumatismo por Reperfusão Miocárdica/genética , Traumatismo por Reperfusão Miocárdica/patologia , Miocárdio/metabolismo , Miocárdio/patologia , RNA Mensageiro/genética , Ratos , Ratos Wistar , Regulação para Cima/efeitos dos fármacos
9.
Int J Food Microbiol ; 186: 74-83, 2014 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-25016206

RESUMO

The objective of this study was to develop a probabilistic model in order to determine the contamination level of Salmonella and Listeria monocytogenes in ready-to-cook poultry meat, after a high pressure (HP) treatment. The model included four steps: i) Reception of raw meat materials, mincing and mixing meat, ii) Partitioning and packaging into 200-g modified atmosphere packs, iii) High pressure treatment of the meat, and iv) Storage in chilled conditions until the end of the shelf-life. The model excluded the cooking step and consumption at consumer's home as cooking practices and heating times are highly variable. The initial contamination level of Salmonella and L. monocytogenes was determined using data collected in meat primary processing plants. The effect of HP treatment and potassium lactate on microbial reduction was assessed in minced meat, using a full factorial design with three high pressure treatments (200, 350 and 500 MPa), three holding times (2, 8 and 14 min) and two potassium lactate concentrations (0 or 1.8% w/w). The inactivation curves fitted with a Weibull model highlighted that the inactivation rate was significantly dependent on the HP treatment. From the literature, it was established that Salmonella was not able to grow in the presence of lactate, under modified atmosphere and chilled conditions whereas the growth of L. monocytogenes was determined using an existing model validated in poultry (available in Seafood Spoilage and Safety Predictor software, V. 3.1). Once implemented in the Excel add-in @Risk, the model was run using Monte Carlo simulation. The probability distribution of contamination levels was determined for various scenarios. For an average scenario such as an HP treatment of 350 MPa for 8 min, of 200 g minced meat containing 1.8% lactate (pH 6.1; aw 0.96), conditioned under 50% CO2, the prevalence rate of Salmonella and L. monocytogenes, after a 20-day storage at 6 °C was estimated to be 4.1% and 7.1%, respectively. The contamination level was low considering that the product is going to be cooked by the consumer afterwards: the 99th percentile of the distribution was equal to -2.3log cfu/g for Salmonella and 0.5log cfu/g for L. monocytogenes. More generally, the model developed here from raw material reception up to the end of the shelf-life enables to recommend combinations of HP treatment and lactate formulation to guarantee an acceptable microbial concentration before cooking.


Assuntos
Lactatos/farmacologia , Listeria monocytogenes/isolamento & purificação , Carne/microbiologia , Modelos Biológicos , Pressão , Salmonella/isolamento & purificação , Animais , Antibacterianos/farmacologia , Simulação por Computador , Culinária , Manipulação de Alimentos/normas , Listeria monocytogenes/efeitos dos fármacos , Aves Domésticas , Salmonella/efeitos dos fármacos
10.
J Fish Biol ; 81(5): 1754-62, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23020573

RESUMO

Comparison of nine isogenic lines of rainbow trout Oncorhynchus mykiss kept in the same environment showed significant genetic determinism of phenotypic plasticity assessed through body mass measurements. Ranking of lines differed between two tested environments.


Assuntos
Oncorhynchus mykiss/genética , Fenótipo , Análise de Variância , Animais , Cruzamento , Meio Ambiente , Especificidade da Espécie , Fatores de Tempo
11.
J Dairy Sci ; 94(5): 2418-24, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21524533

RESUMO

α-Lactalbumin (Alac) is one of the major milk proteins. Its gene expression is restricted to epithelial cells of the lactating mammary gland. The Alac interaction with a uridine 5'-diphosphate-galactosyltransferase induces lactose synthesis, a major osmotic regulator of milk secretion. Other functions attributed to this protein include induction of apoptosis and anti-inflammatory activities. To assess if forced expression of this gene during early gestation or involution could affect mammary physiology, an Alac-encoding minigene was expressed in transgenic mice under the transcriptional regulation of the mouse mammary tumor virus promoter. The mammary expression did not interfere with gestation, resulted in a slight increase in milk yield as indirectly assessed by the 11% increased growth rate of the pups reared by transgenic females compared with that of those reared by control mice, and induced a slight delay in the early involution process, as demonstrated by histological analyses. The use of the mouse mammary tumor virus promoter resulted in Alac expression in several nonmammary tissues, such as the brain, the testis, the ovary, and the uterus. Although it did not affect male reproductive performances, it induced a female subfertile phenotype, characterized by embryonic implantation failure in the transgenic female reproductive tract.


Assuntos
Fertilidade , Lactalbumina/metabolismo , Lactação/fisiologia , Vírus do Tumor Mamário do Camundongo/genética , Regiões Promotoras Genéticas , Animais , Feminino , Expressão Gênica , Lactalbumina/genética , Masculino , Glândulas Mamárias Animais/metabolismo , Camundongos , Camundongos Transgênicos
12.
Int J Cosmet Sci ; 33(2): 138-43, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20646083

RESUMO

Ceramides, specific lipid components of the skin, represent 35-40% of the intercellular cement binding cells together and contributing to skin hydration. A wheat extract rich in ceramides and digalactosyl-diglycerides was developed by Hitex in two forms: wheat extract oil (WEO) and wheat extract powder (WEP). In vitro tests and two clinical studies demonstrated promising efficacy results with WEP on skin hydration. To confirm these early results, a double-blind, randomized, placebo-controlled study was carried out on 51 women aged 20-63 years with dry to very dry skin who received either 350 mg of WEO or placebo for 3 months. Evaluation of skin hydration on legs, arms and face, assessed at baseline (D0) and at study end (D84) was performed by the dermatologist using dermatological scores (dryness, roughness, erythema), skin hydration measurement (corneometry) and self-assessment scores (Visual Analogue Scale: VAS). Perceived efficacy was noted by participants throughout the study; tolerability and overall acceptability of the study products were evaluated by the dermatologist and the participants at the end of study. Skin hydration was significantly increased between D0 and D84 on the arms (P < 0.001) and legs (P = 0.012) in the WEO group compared with placebo. Even if no significant statistical differences between groups were observed for the dermatological evaluation, skin dryness and redness tended to be reduced in the WEO group. Moreover, from D0 to D84, the VAS index had a tendency to increase in favour of WEO for the overall skin hydration (P = 0.084) indicating that participants perceived an improvement. The WEO capsules were perceived by participants as being more effective than placebo on all skin dryness signs. In conclusion, WEO capsules were well tolerated and appreciated. After 3 months' treatment, a significant increase in skin hydration and an improvement in associated clinical signs were observed in women with dry skin.


Assuntos
Ceramidas/administração & dosagem , Extratos Vegetais/administração & dosagem , Pele/efeitos dos fármacos , Triticum/química , Adulto , Método Duplo-Cego , Impedância Elétrica , Feminino , Humanos , Pessoa de Meia-Idade , Satisfação do Paciente , Projetos Piloto , Pele/química , Pele/metabolismo , Adulto Jovem
13.
Arch Pediatr ; 17(7): 1047-55, 2010 Jul.
Artigo em Francês | MEDLINE | ID: mdl-20472409

RESUMO

The aim of our study was to determine the different characteristics of infective endocarditis in children without underlying heart disease. This was a descriptive, retrospective study including all cases of infective endocarditis without underlying heart disease occurring in children under 18 years of age, hospitalized at the Timone Children's Hospital in Marseille, France, between 1997 and 2008. The clinical, microbiological, and echocardiography data; treatment; and outcome were reviewed for each case. Over an 11-year period, 26 children were hospitalized with infective endocarditis. Eleven children (7 boys) had no underlying heart disease (42 %). Their mean age was 8 years and 3 months. Underlying conditions including neoplasm, preterm birth, and central venous catheter were found in 6 cases. A heart murmur was observed in 82 % of the children. A microorganism was isolated in 10 children (91 %). Staphylococcus aureus was the most common agent (45 %), followed by fungi (18 %). Echocardiography detected cardiac complications in 7 cases (64 %). Ninety-one percent of the children received intravenous antibiotics for a mean duration of 45 days. Eighty-two percent of our patients required surgical intervention. In our series, 91 % of the patients met the modified Duke criteria defining infective endocarditis. In-hospital mortality was 11 %. Embolic complications were seen in 5 cases (45 %), patients whose cultures yielded S. aureus or fungal organisms were more likely to present complications. Infective endocarditis without heart disease has particular features that differ from those of congenital heart disease. This diagnosis must be considered when predisposing factors are present.


Assuntos
Endocardite Bacteriana/diagnóstico , Cardiopatias/complicações , Adolescente , Antibacterianos/uso terapêutico , Proteína C-Reativa/análise , Criança , Pré-Escolar , Endocardite Bacteriana/microbiologia , Endocardite Bacteriana/terapia , Feminino , Sopros Cardíacos/complicações , Mortalidade Hospitalar , Humanos , Lactente , Recém-Nascido , Infusões Intravenosas , Masculino , Estudos Retrospectivos , Infecções Estafilocócicas/complicações , Infecções Estafilocócicas/tratamento farmacológico
14.
J Appl Microbiol ; 108(1): 256-65, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19645768

RESUMO

AIMS: To determine the reducing capacity of Listeria monocytogenes and to highlight the effect of redox potential on its growth parameters. METHODS AND RESULTS: The reducing capacity of L. monocytogenes was monitored in Brain Heart Infusion Broth media at different initial redox potential (Eh) and pH at 37 degrees C. The effect of Eh obtained by gas flushing (air, N(2) and N(2)-H(2)) or by adding potassium ferricyanide and dithiotreitol in concentration from 1 to 10 mmol l(-1)on L. monocytogenes growth parameters at pH 6.0, 7.0 and 8.0 was investigated. A total change of 539 mV (+ or - 44 mV) from an initial redox value of +330 + or - 8 mV to a more negative potential in redox curves was observed resulting from L. monocytogenes growth at pH 7.0 at 37 degrees C. A significant influence of pH and redox potential on L. monocytogenes lag phase of growth was shown (P < 0.05). CONCLUSIONS: Listeria monocytogenes exhibited longer lag phase in reducing conditions and at pH 6.0. The method used to modify the redox potential was shown to have no effect on growth parameters at pH 7.0. SIGNIFICANCE AND IMPACT OF THE STUDY: The provided information on the extending lag time and the possible delayed growth of this major pathogen in reducing conditions might be useful for its control in foods.


Assuntos
Ditiotreitol/farmacologia , Ferricianetos/farmacologia , Listeria monocytogenes/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Oxirredução/efeitos dos fármacos
15.
J Appl Microbiol ; 105(3): 875-83, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18410341

RESUMO

AIMS: Study the effect of redox potential and pH of the heating media on Listeria monocytogenes heat resistance and model its action at fixed temperature. METHODS AND RESULTS: The heat resistance of Listeria monocytogenes at 58 degrees C was studied in Brain Heart Infusion broth as a function of pH (from 5.0 to 7.0) and redox potential (E(h7)). The media redox was adjusted with nitrogen gas, potassium ferricyanide and dithiothreitol. A Weibull model was used to fit survival curves. The heat resistance parameter (delta(58 degrees C)) was estimated from each inactivation curve. A major effect of pH was observed. Bigelow model was used to describe the effect of redox potential on the apparent L. monocytogenes heat resistance. The highest delta(58 degrees C) values have been obtained at pH 7.0 and oxidizing conditions. CONCLUSIONS: The developed model indicates that the E(h7) has a significant effect and varied depending on the pH of the heating media. The z(redox) values, calculated from delta(58 degrees C) allowed quantifying the influence of heating media redox potential on L. monocytogenes thermal inactivation. SIGNIFICANCE AND IMPACT OF THE STUDY: The obtained model shows the action of redox potential on L. monocytogenes thermal destruction and might be useful to take into account in food thermal processes.


Assuntos
Microbiologia de Alimentos , Conservação de Alimentos/métodos , Temperatura Alta , Listeria monocytogenes/fisiologia , Técnicas Bacteriológicas , Contagem de Colônia Microbiana , Manipulação de Alimentos/métodos , Listeria monocytogenes/metabolismo , Modelos Biológicos , Oxirredução
16.
Water Res ; 42(8-9): 2213-9, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18160092

RESUMO

The aim of the study was to examine the hypothesis proposed by Evans et al. [2003. Hazards of healthy living: bottled water and salad vegetables as risk factors for Campylobacter infection. Emerg. Infect. Dis. 9(10), 1219-1225] that mineral bottled water accidentally contaminated by Campylobacter jejuni would represent a risk factor for Campylobacter infection. Culturability of C. jejuni cells inoculated in low- and high-mineral bottled water during storage at 4 degrees C in the dark was performed by surface plating and modelled using the Weibull model. The loss of C. jejuni culturability observed in all conditions tested was shown to be dependent on strain, preculture condition and water composition. Following inoculation of C. jejuni, the rapid loss of culturability was not correlated to complete cell death as the passage into embryonated eggs enabled recovery of cells from the viable but non-culturable state. In conclusion, the sanitary risk associated with contaminated bottled water cannot be excluded although it is presumably low. Culture conditions, strain and water type must be taken into account in the evaluation of the risk factors as they influence significantly Campylobacter survival in water.


Assuntos
Campylobacter jejuni/isolamento & purificação , Modelos Teóricos , Microbiologia da Água , Abastecimento de Água , Contagem de Colônia Microbiana , Minerais
17.
Can J Microbiol ; 53(7): 813-21, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17898836

RESUMO

In response to consumer preferences for high quality foods that are as close as possible to fresh products, athermal technologies are being developed to obtain products with high levels of organoleptic and nutritional quality but free of any health risks. Pulsed light is a novel technology that rapidly inactivates pathogenic and food spoilage microorganisms. It appears to constitute a good alternative or a complement to conventional thermal or chemical decontamination processes. This food preservation method involves the use of intense, short-duration pulses of broad-spectrum light. The germicidal effect appears to be due to both photochemical and photothermal effects. Several high intensity flashes of broad spectrum light pulsed per second can inactivate microbes rapidly and effectively. However, the efficacy of pulsed light may be limited by its low degree of penetration, as microorganisms are only inactivated on the surface of foods or in transparent media such as water. Examples of applications to foods are presented, including microbial inactivation and effects on food matrices.


Assuntos
Descontaminação/métodos , Irradiação de Alimentos/métodos , Microbiologia de Alimentos , Luz
19.
J Evol Biol ; 20(2): 503-16, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17305816

RESUMO

In Zea mays L., we studied the molecular evolution of Shrunken2 (Sh2), a gene that encodes the large subunits of a major enzyme in endosperm starch biosynthesis, ADP-glucose pyrophosphorylase. We compared 4669 bp of the Sh2 coding region on 50 accessions of maize and teosinte. Very few nucleotide polymorphisms were found when compared with other genes in Z. mays, revealing an effect of purifying selection in the whole species that predates domestication. Additionally, the comparison of Sh2 sequences in all Z. mays subspecies and outgroups Z. diploperennis and Tripsacum dactyloides suggests the occurrence of an ancient selective sweep in the Sh2 3' region. The amount and nature of nucleotide diversity are similar in both maize and teosinte, confirming previous results that suggested that Sh2 has not been involved in maize domestication. The very low level of nucleotide diversity as well as the highly conserved protein sequence suggest that natural selection retained effective Sh2 allele(s) long before agriculture started, making human selection inefficient on this gene.


Assuntos
Evolução Molecular , Proteínas de Plantas/genética , Seleção Genética , Zea mays/genética , Alelos , Sequência de Bases , Cruzamento , Frequência do Gene , Haplótipos , Desequilíbrio de Ligação , Dados de Sequência Molecular , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/classificação , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único , Alinhamento de Sequência , Análise de Sequência de DNA
20.
Epileptic Disord ; 6(4): 293-6, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15634627

RESUMO

A patient suffering from juvenile myoclonic epilepsy experienced myoclonic jerks, fairly regularly, while playing chess. The myoclonus appeared particularly when he had to plan his strategy, to choose between two solutions or while raising the arm to move a chess figure. Video-EEG-polygraphy was performed, with back averaging of the myoclonus registered during a chess match and during neuropsychological testing with Kohs cubes. The EEG spike wave complexes were localised in the fronto-central region. [Published with video sequences].


Assuntos
Eletroencefalografia , Epilepsias Mioclônicas/diagnóstico , Epilepsia Reflexa/diagnóstico , Jogos e Brinquedos , Processamento de Sinais Assistido por Computador , Gravação em Vídeo , Adulto , Anticonvulsivantes/uso terapêutico , Atenção/efeitos dos fármacos , Atenção/fisiologia , Eletroencefalografia/efeitos dos fármacos , Eletromiografia/efeitos dos fármacos , Epilepsias Mioclônicas/tratamento farmacológico , Epilepsias Mioclônicas/fisiopatologia , Epilepsia Reflexa/tratamento farmacológico , Epilepsia Reflexa/fisiopatologia , Potenciais Evocados/efeitos dos fármacos , Potenciais Evocados/fisiologia , Lobo Frontal/efeitos dos fármacos , Lobo Frontal/fisiopatologia , Jogos Experimentais , Humanos , Masculino , Testes Neuropsicológicos , Resolução de Problemas/efeitos dos fármacos , Resolução de Problemas/fisiologia , Desempenho Psicomotor/efeitos dos fármacos , Desempenho Psicomotor/fisiologia , Ácido Valproico/uso terapêutico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...