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151.
Christelle Kouakou Jean-Pascal Bergé Régis Baron Laurent Lethuaut Carole Prost 《Journal Of Aquatic Food Product Technology》2013,22(5):453-467
The aim of this work was to study the effect of adding sugar during proteolysis to promote the Maillard reaction and mask the initial fish odor and off-flavors generated. An experimental design, based on the Doehlert plan, was used to study the influence of hydrolysis conditions (time, temperature, sugar, and antioxidant addition) on the odor characteristics of hydrolysates, soluble protein levels, and amino acid content. Results showed that the lowest level of sugar (10 g of D-xylose added to 1 kg of by-products) was enough to develop a grilled odor in hydrolysates. In the hydrolysis conditions used—i.e., enzyme inactivation at 95°C for 30 min—hydrolysis temperature had no effect on grilled odor production but significantly affected the soluble protein fraction, as did hydrolysis time. Soluble protein content and essential amino acid content increased with the enzymatic reaction but were not modified by adding sugar. Hydrolysis conditions that promote Maillard reactions while keeping a nutritional balance have been identified. 相似文献
152.
153.
The plasma membrane from spermatozoa of rainbow trout was isolated by four techniques: sonication, hypotonic shock, mechanical homogenization after freeze-thawing, and nitrogen cavitation, in combination with continuous sucrose gradient centrifugation. Nitrogen cavitation (900 PSI, 20 min equilibration at 4°C) was the most effective technique.Following nitrogen cavitation, four bands were recovered in the sucrose gradient at densities 1.03, 1.05, 1.09 and 1.15 g/ml. Electron microscopy revealed membrane vesicles of various sizes in bands 1 to 3, while enzyme analysis revealed a 3.9 to 5.5-fold enrichment in 5'-nucleotidase and little contamination by lactate dehydrogenase (cytosol) and succinic dehydrogenase (mitochondria). Lipid analysis of bands 1 and 2 indicated a 6 to 7-fold enrichment in cholesterol and a cholesterol: phospholipid ratio of 0.59–0.70. Seven classes of phospholipids were present in bands 1–3 with no significant differences observed among bands. These data indicate that the vesicles (in bands 1 and 2) obtained after nitrogen cavitation are primarily plasma membranes. Membranes in band 3 appear to be slightly contaminated with nuclear membranes.Most of the plasma membrane proteins were acidic to neutral. The 2 main membrane proteins were 42 and 30 Kilodaltons. 相似文献
154.
Isabelle Vahirua‐Lechat Frédéric Laure Jean René LeCoz Jean Pierre Bianchini Mereani Bellais Gilles Le Moullac 《Aquaculture Research》2008,39(16):1739-1746
The fatty acid and sterol composition of the oyster Pinctada margaritifera during oogenesis and in eggs was analysed. No major differences were observed during oogenesis, but the egg composition was significantly different from that of gonads. The amount of saturated fatty acids was the highest in eggs and the C16:0 predominant (P<5%); by contrast, the amount of 22:6(n‐3) was significantly lower (P<5%) than in gonads. No major differences were observed for the polar lipid (PL) composition during oogenesis. The main free sterols in gonads and eggs were cholesterol and brassicasterol. Among free sterols, the proportion of cholesterol diminished continuously from the beginning to the end of gonad maturation, and this decrease persisted in eggs after spawning. Cholesterol represented 40% to 55% of the sterol ester encountered in gonad and eggs. This study allowed us to investigate the fatty acid and sterol composition during oogenesis of the pearl oyster P. margaritifera, leading to a clearer understanding of the nutritional requirements of pearl oyster during the reproduction process. 相似文献
155.
Maintaining connectivity among local populations in a fragmented landscape is crucial for the survival of many species. For
isolated habitat patches, stochastic fluctuations and reduced gene flow can lead to high risk of extinction. The connectivity
of the landscape is especially crucial for the carabid species living in the fragmented forests of the Bereg plain (NE Hungary
and W Ukraine) because a highway will be constructed through the plain. Our purpose is to (1) evaluate the impacts of three
possible highway tracks, (2) suggest a solution that is realistic with less impact on connectivity than other plans and (3)
discuss how to decrease the disadvantageous effects of each track. Our results, based on a network analysis of landscape graph
of patches and ecological corridors, indicate that the intended highway could have deleterious consequences on forest-living
carabids. Relatively simple actions, like the establishment of stepping stones, could compensate for the loss of habitat connectivity
and promote the survival of carabids, or minor modifications in one possible track could diminish its adverse effects. While
many other studies would be needed for a comprehensive assessment of the biotic impact of the highway, we provide an example
on the usefulness of network analysis for land use management.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
156.
This study aimed at capturing the spatial variability of landscape patterns and their trajectories of change from 1950 to
2000 within a watershed, which is representative of areas of intensive agricultural use. After an analysis of landscape features
changes for the entire watershed based on aerial photographs, hierarchical clustering analysis provided a typology of landscape
patterns for the cadastral lots. Following that, the trajectory of change of each lot was characterized (nature, importance,
direction, rate of change). Seven types of landscape patterns are distinguished by the relative importance of different classes
of landscape features and 51 trajectories of change were identified for the lots. The analysis shows that although the majority
of lots were subjected to a homogenization of their landscape patterns since 1950, this trend is not entirely uniform and
that since 2000 it occurs alongside trends towards diversification of certain landscape features on some lots. Furthermore,
nearly a third of the lots are not following the main trajectories of change detected. Thus, the results suggest that extrinsic
forces (policies, technologies) that are directing main changes in areas of intensive agricultural use toward uniformity could
be modulated by internal forces (uses and values of the population). A better understanding of theses internal forces seems
crucial to manage landscapes. From a methodology standpoint, although the hierarchical clustering analyses appear useful for
understanding the spatial and temporal variability of landscape patterns, particular attention must be given to validating
the typology chosen to characterize them. 相似文献
157.
Eddy covariance (EC) systems are being used to assess the accuracy of remote sensing methods in mapping surface sensible and
latent heat fluxes and evapotranspiration (ET) from local to regional scales, and in crop coefficient development. Therefore,
the objective was to evaluate the accuracy of EC systems in measuring sensible heat (H) and latent heat (LE) fluxes. For this
purpose, two EC systems were installed near large monolithic weighing lysimeters, on irrigated cotton fields in the Texas
High Plains, during the months of June and July 2008. Sensible and latent heat fluxes were underestimated with an average
error of about 30%. Most of the errors were from nocturnal measurements. Energy balance (EB) closure was 73.2–78.0% for daytime
fluxes. Thus, daylight fluxes were adjusted for lack of EB closure using the Bowen ratio/preservation of energy principle,
which improved the resulting EC heat flux agreement with lysimetric values. Further adjustments to EC-based ET included nighttime
ET (composite) incorporation, and the use of ‘heat flux source area’ (footprint) functions to compensate ET when the footprint
expanded beyond the crop field boundary. As a result, ET values remarkably matched lysimetric ET values, with a ‘mean bias
error ± root mean square error’ of −0.03 ± 0.5 mm day−1 (or −0.6 ± 10.2%). 相似文献
158.
A. Pérez-Pastor R. Domingo A. Torrecillas Ma. C. Ruiz-Sánchez 《Irrigation Science》2009,27(3):231-242
During four growing seasons, 10-year-old apricot trees (Prunus armeniaca L., cv. ‘Búlida’) were submitted to three different drip irrigation regimes: (1) a control treatment, irrigated at 100% of
seasonal crop evapotranspiration (ETc), (2) a continuous deficit irrigation (DI) treatment, irrigated at 50% of the control
treatment, and (3) a regulated deficit irrigation (RDI) treatment, irrigated at 100% of ETc during the critical periods, which
correspond to stage III of fruit growth and 2 months after harvest (early postharvest), and at 25% of ETc during the rest
of the non-critical periods in the first two growing seasons and at 40% of ETc in the third and fourth. Soil–plant–water relation
parameters were sensitive to the water deficits applied, which caused reductions in leaf and soil water potentials. The longer
and severer deficits of the RDI treatment decreased fruit yield in the first two seasons. The RDI treatment pointed to two
threshold values that defined the level at which both plant growth and yield were negatively affected with respect to the
control treatment: (1) a predawn leaf water potential of around −0.5 MPa during the critical periods, and (2) a 22% drop in
irrigation water. The total yield obtained in the DI treatment was significantly reduced in all the years studied due to the
lower number of fruits per tree. No changes in the physical characteristics of fruits were observed at harvest. RDI can be
considered a useful strategy in semiarid areas with limited water resources. 相似文献
159.
A flow cytometric virus-binding assay that directly visualizes the binding and entry of infectious pancreatic necrosis virus (IPNV), infectious haematopoietic necrosis virus (IHNV) and virus haemorrhagic septicaemia virus (VHSV) to several cell lines was established. The highest efficiency of binding was shown by the BF-2 cell line and this was used to study, at the attachment level, the interactions of these cells with salmonid fish viruses in coinfections, and to further determine if the earliest stage of the viral growth cycle could explain the previously described loss of infectivity of IHNV when IPNV is present. Our results demonstrated that IPNV binds to around 88% of cells either in single or dual infections, whereas IHNV attachment always decreased in the presence of any of the other viruses. VHSV binding was not affected by IPNV, but coinfection with IHNV reduced the percentage of virus-binding cells, which suggests competition for viral receptors or co-receptors. Internalization of the adsorbed IHNV was not decreased by coinfection with IPNV, so the hypothetical competence could be restricted to the binding step. Treatment of the cells with antiviral agents, such as amantadine or chloroquine, did not affect the binding of IPNV and VHSV, but reduced IHNV binding by more than 30%. Tributylamine affected viral binding of the three viruses to different degrees and inhibited IPNV or IHNV entry in a large percentage of cells treated for 30 min. Tributylamine also inhibited IHNV cytopathic effects in a dose-dependent manner, decreasing the virus yield by 4 log of the 50% endpoint titre, at 10 mm concentration. IPNV was also inhibited, but at a lower level. The results of this study support the hypothesis that IHNV, in contrast to VHSV or IPNV, is less efficient at completing its growth cycle in cells with a simultaneous infection with IPNV. It can be affected at several stages of viral infection and is more sensitive to the action of antiviral compounds. 相似文献
160.
Variability in conspecific predation among longnose lancetfish Alepisaurus ferox in the western Indian Ocean 总被引:1,自引:0,他引:1
Evgeny V Romanov Frédéric Ménard Veniamin V Zamorov Michel Potier 《Fisheries Science》2008,74(1):62-68
ABSTRACT: Conspecific predation among longnose lancetfish Alepisaurus ferox was investigated in four spatio-temporal strata of the western Indian Ocean. The cannibalism level varied from 0 to 45.5% by frequency of occurrence and was negatively related with abundance of non-evasive prey (such as crustaceans Charybdis smithii and Natosquilla investigatoris ) and foraging success. Predation by lancetfish is often described as a non-selective process, constrained by local prey availability and by its feeding speed during an attack of prey. Our results show that lancetfish may adapt its opportunistic foraging behavior, feeding on non-conspecific abundant prey such as crustaceans when available, and switching to a high level of conspecific predation in poor waters. 相似文献