SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

Cheret, Romuald; Delbarre Ladrat, Christine; Verrez-bagnis, Veronique; De Lamballerie, Marie.

Calpains (calcium-activated neutral proteases) of sea bass (Dicentrarchus labrax L.) muscle may participate in the degradation of muscle tissue during postmortem storage. These enzymes are regulated by calpastatin, their endogenous specific inhibitor. The objective of this study was to evaluate the changes encountered by the calpain system during the postmortem storage of fish muscle after high-pressure treatment. From 100 MPa, high-pressure treatment of purified calpains results in a loss of their activity as well as in the dissociation of the heterodimeric form. In muscle, the high-pressure processing decreases the initial activity of calpain. This loss in activity may be due to an inactivation by a change of structure. Initial calpastatin activity is...

Tipo: Text

Palavras-chave: Postmortem denaturation; High pressure; Fish; Calpain system.

Ano: 2007

URL: http://archimer.ifremer.fr/doc/2007/publication-2786.pdf

Effect of lysozyme or nisin on survival of some bacteria treated with high pressure at subzero temperature

BJM

Malinowska-Pańczyk,Edyta; Kołodziejska,Ilona.

The aim of this work was to examine the inactivation of some Gram-positive and Gram-negative bacteria exposed to the pressure of 193 MPa at -20 °C in the presence of lysozyme or nisin at concentration of 400 mg/ml. The highest effect of pressure at subzero temperature and lysozyme was found with pressure sensitive Pseudomonas fluorescens; viable cells of this strain were not detected in 1 ml of sample after combined treatment. The action of pressure at subzero temperature and lysozyme or nisin against Escherichia coli led to synergistic reduction by 0.7 or 1.6 log cycles, respectively, while it was practically insignificant for two Staphylococcus aureus strains. Viability loss of E. coli and S. aureus occurred during storage for 20 h of the samples at 37...

Effects of high pressure on texture and microstructure of sea bass (Dicentrarchus labrax L.) fillets

Palavras-chave: Inactivation of microorganisms; High pressure; Subzero temperature; Lysozyme; Nisin.

Ano: 2009

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822009000400006

Cheret, Romuald; Chapleau, Nicolas; Delbarre Ladrat, Christine; Verrez-bagnis, Veronique; De Lamballerie, Marie.

High pressure is an innovative non-thermal food-preservation technology. We studied the effect of high-pressure treatment up-to 500 MPa for 5 min on physical characteristics of sea bass fillets after 0, 7, and 14 d of refrigerated storage.. Color results exhibited an increase of lightness and a slight change of hue, which might be imperceptible in cooked fish. High-pressure treatment induced a decrease of exudation and water-holding capacity Pressure treatment above 300 MPa provoked higher fish hardness after storage than in untreated sample, proving the ability of high pressure to improve textural, quality of chilled, stored fish fillet. These assessments were corroborated with microstructure observations. We showed that high-pressure treatment at 500 MPa...

Tipo: Text

Palavras-chave: Preservation; Microstructure; Texture profile analysis; High pressure; Fish.

Ano: 2005

URL: http://archimer.ifremer.fr/doc/2005/publication-734.pdf

Effet des hautes pressions sur les indicateurs de maturation de la viande et d'altération du muscle de poisson

High pressure-sensitive gene expression in Lactobacillus sanfranciscensis

Cheret, Romuald.

This study deals with the influence of the high pressure process on the ageing of meat and the degradation of the fish muscle. The aim is to characterize the effect of the high pressure treatment on the protease activities responsible for degradation for the sea bass muscle (Dicentrarchus labrax L.) and bovine muscle (Biceps femoris), but also on the texture, the colour and the microstructure. The samples were pressurized between 0 and 500 MPa during 5 minutes, and were stored at 4°C. The different proteasic systems involved in the post-mortem degradation of the muscle (mainly cathepsins and calpains) were quantified after the high pressure treatment and during the post-mortem storage. The results shown that the sensitivity of the proteases depended on...

Tipo: Text

Palavras-chave: Enzymes; Muscular proteins; Bovine muscle; Fish muscle; Proteases; High pressure; Protéines musculaires; Enzymes; Viande bovine; Muscle de poisson; Protéases; Hautes pressions.

Ano: 2005

URL: http://archimer.ifremer.fr/doc/2005/these-553.pdf

Vogel,R.F.; Pavlovic,M.; Hörmann,S.; Ehrmann,M.A..

Lactobacillus sanfranciscensis is a Gram-positive lactic acid bacterium used in food biotechnology. It is necessary to investigate many aspects of a model organism to elucidate mechanisms of stress response, to facilitate preparation, application and performance in food fermentation, to understand mechanisms of inactivation, and to identify novel tools for high pressure biotechnology. To investigate the mechanisms of the complex bacterial response to high pressure we have analyzed changes in the proteome and transcriptome by 2-D electrophoresis, and by microarrays and real time PCR, respectively. More than 16 proteins were found to be differentially expressed upon high pressure stress and were compared to those sensitive to other stresses. Except for one...

Processing Strategies to Inactivate Enteric Viruses in Shellfish

Palavras-chave: High pressure; Lactobacillus sanfranciscensis; Proteome; Transcriptome; Stress response.

Ano: 2005

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000800013

Richards, Gary P.; Mcleod, Catherine; Le Guyader, Soizick.

Noroviruses, hepatitis A and E viruses, sapovirus, astrovirus, rotavirus, Aichi virus, enteric adenoviruses, poliovirus, and other enteroviruses enter shellfish through contaminated seawater or by contamination during handling and processing, resulting in outbreaks ranging from isolated to epidemic. Processing and disinfection methods include shellfish depuration and relaying, cooking and heat pasteurization, freezing, irradiation, and high pressure processing. All the methods can improve shellfish safety; however, from a commercial standpoint, none of the methods can guarantee total virus inactivation without impacting the organoleptic qualities of the shellfish. Noroviruses cause the majority of foodborne viral illnesses, yet there is conflicting...

Tipo: Text

Palavras-chave: Shellfish; Processing; Norovirus; Hepatitis A virus; Depuration; High pressure; Heat inactivation.

Ano: 2010

URL: http://archimer.ifremer.fr/doc/00011/12253/9199.pdf

Protein dynamics: hydration and cavities

Heremans,K..

The temperature-pressure behavior of proteins seems to be unique among the biological macromolecules. Thermodynamic as well as kinetic data show the typical elliptical stability diagram. This may be extended by assuming that the unfolded state gives rise to volume and enthalpy-driven liquid-liquid transitions. A molecular interpretation follows from the temperature and the pressure dependence of the hydration and cavities. We suggest that positron annihilation spectroscopy can provide additional quantitative evidence for the contributions of cavities to the dynamics of proteins. Only mature amyloid fibrils that form from unfolded proteins are very resistant to pressure treatment.

Proteins and proteolytic activity changes during refrigerated storage in sea bass (Dicentrarchus labrax L.) muscle after high-pressure treatment

Palavras-chave: Stability diagram; Thermodynamics; High pressure; Unfolding; Amyloid fibrils; Protein dynamics.

Ano: 2005

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000800002

Cheret, Romuald; Hernandez Andres, Aránzazu; Delbarre Ladrat, Christine; De Lamballerie, Marie; Verrez-bagnis, Veronique.

Contrary to other preservation methods like thermal treatments, high pressure can destroy microorganisms without affecting the nutritional quality, color, or food texture. The firm texture of fish flesh is an important quality parameter. During the refrigerated storage, the tissue becomes softer and the muscle is deteriorated by different proteases. The aim of this study was to study the modification of the fish muscle proteins after high-pressure treatment during the refrigerated storage and to evaluate the effect of high-pressure treatment level on the post-mortem protein changes and enzyme activities. The calpain activity decreased with the high-pressure treatment and evolved differently during the refrigerated storage, depending on the level of...

Tipo: Text

Palavras-chave: Cathepsins; Calpains; Sarcoplasmic proteins; Myofibrillar proteins; Post mortem denaturation; High pressure; Fish.

Ano: 2006

URL: http://archimer.ifremer.fr/doc/2006/publication-1708.pdf

SEPARATION OF SATURED AND UNSATURATED FATTY ACIDS FROM PALM FATTY ACIDS DISTILLATES IN CONTINUOUS MULTISTAGE COUNTERCURRENT COLUMNS WITH SUPERCRITICAL CARBON DIOXIDE AS SOLVENT: A PROCESS DESIGN METHODOLOGY

Ciênc. Tecnol. Aliment.

MACHADO,Nélio Teixeira; BRUNNER,Gerd.

In this work the separation of multicomponent mixtures in counter-current columns with supercritical carbon dioxide has been investigated using a process design methodology. First the separation task must be defined, then phase equilibria experiments are carried out, and the data obtained are correlated with thermodynamic models or empirical functions. Mutual solubilities, Ki-values, and separation factors <FONT FACE="Symbol">a</font>ij are determined. Based on this data possible operating conditions for further extraction experiments can be determined. Separation analysis using graphical methods are performed to optimize the process parameters. Hydrodynamic experiments are carried out to determine the flow capacity diagram. Extraction...

Stabilization of partially folded states in protein folding/misfolding transitions by hydrostatic pressure

Palavras-chave: VLE; High pressure; Separation analysis; Hydrodynamics; Experiments.

Ano: 1997

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20611997000400004

Ferreira,S.T.; Chapeaurouge,A.; De Felice,F.G..

In the last few years, hydrostatic pressure has been extensively used in the study of both protein folding and misfolding/aggregation. Compared to other chemical or physical denaturing agents, a unique feature of pressure is its ability to induce subtle changes in protein conformation, which allow the stabilization of partially folded intermediate states that are usually not significantly populated under more drastic conditions (e.g., in the presence of chemical denaturants or at high temperatures). Much of the recent research in the field of protein folding has focused on the characterization of folding intermediates since these species appear to be involved in a variety of disease-causing protein misfolding and aggregation events. The exact mechanisms of...

The effect of hydrostatic pressure on membrane-bound proteins

Palavras-chave: High pressure; Protein folding; Misfolding; Amyloid; Aggregation.

Ano: 2005

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000800009

Scarlata,S..

Many cellular proteins are bound to the surfaces of membranes and participate in various cell signaling responses. Interactions between this group of proteins are in part controlled by the membrane surface to which the proteins are bound. This review focuses on the effects of pressure on membrane-associated proteins. Initially, the effect of pressure on membrane surfaces and how pressure may perturb the membrane binding of proteins is discussed. Next, the effect of pressure on the activity and lateral association of proteins is considered. We then discuss how pressure can be used to gain insight into these types of proteins.

The powerful high pressure tool for protein conformational studies

Palavras-chave: High pressure; Membrane proteins; Volume changes; Protein-membrane associations; Protein-protein association; Lateral interactions.

Ano: 2005

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000800007

Marchal,S.; Torrent,J.; Masson,P.; Kornblatt,J.M.; Tortora,P.; Fusi,P.; Lange,R.; Balny,C..

The pressure behavior of proteins may be summarized as a the pressure-induced disordering of their structures. This thermodynamic parameter has effects on proteins that are similar but not identical to those induced by temperature, the other thermodynamic parameter. Of particular importance are the intermolecular interactions that follow partial protein unfolding and that give rise to the formation of fibrils. Because some proteins do not form fibrils under pressure, these observations can be related to the shape of the stability diagram. Weak interactions which are differently affected by hydrostatic pressure or temperature play a determinant role in protein stability. Pressure acts on the 2º, 3º and 4º structures of proteins which are maintained by...

Volume and energy folding landscape of prion protein revealed by pressure

Palavras-chave: High pressure; Prion protein; Amyloid; Ataxin; Enolase; Butyrylcholinesterase.

Ano: 2005

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000800004

Cordeiro,Y.; Kraineva,J.; Winter,R.; Silva,J.L..

The main hypothesis for prion diseases proposes that the cellular protein (PrP C) can be altered into a misfolded, ß-sheet-rich isoform, the PrP Sc (from scrapie). The formation of this abnormal isoform then triggers the transmissible spongiform encephalopathies. Here, we discuss the use of high pressure as a tool to investigate this structural transition and to populate possible intermediates in the folding/unfolding pathway of the prion protein. The latest findings on the application of high pressure to the cellular prion protein and to the scrapie PrP forms will be summarized in this review, which focuses on the energetic and volumetric properties of prion folding and conversion.