Analysis of two bentonites of enological interest before and after commercial activation by solid Na(2)CO(3)     

Gougeon RD  Soulard M  Miehé-Brendlé J  Chézeau JM  Le Dred R  Jeandet P  Marchal R 《Journal of agricultural and food chemistry》2003,51(14):4096-4100

Two natural calcium-rich bentonites used for the removal of wine proteins, originating from Greece and Turkey, were studied by X-ray diffraction, thermal analysis, and solid state NMR, before and after activation by solid Na(2)CO(3). Exchange of Ca(2+) by Na(+) mainly occurs for cations located at the edge of layers and only weakly for interlayer cations. This Na(2)CO(3) activation process leads to an increased efficiency in the adsorption process of bovine serum albumin (BSA) used as a model protein for both bentonites. A direct correlation is observed between the extent of Ca(2+)/Na(+) exchange, the strength of adsorption of BSA, and the extent of unfolding of BSA backbone.  相似文献   

Comparison of two microalgal diets. 2. Influence on odorant composition and organoleptic qualities of raw oysters (Crassostrea gigas)     

Pennarun AL  Prost C  Haure J  Demaimay M 《Journal of agricultural and food chemistry》2003,51(7):2011-2018

Oyster farming is of real economic interest in France. Oyster farmers attach more and more importance to improving the growth and the quality of their oysters. Some fatty acids known to be aroma precursors originate from microalgae such as Skeletonema costatum and Tahitian isochrysis clone. These microalgae were used to fatten oysters in order to observe their role in the development of oysters' aroma. This study shows that the profile of fatty acids of oysters is influenced by the contribution of fatty acids from the two microalgae (as reported in the first paper in this series: Pennarun, A.-L.; Prost, C.; Haure, J.; Demaimay, M. Comparison of Two Microalgal Diets. 1. Influence on the Biochemical and Fatty Acid Compositions of Raw Oysters (Crassostrea gigas). J. Agric. Food Chem. 2003, 51, 2006-2010 (in this issue)]. As a consequence, a microalgal diet causes changes in oysters' aroma composition. Aroma concentration depends on the content of fatty acids that are aroma precursors in oysters. Some aromas are characteristic of the diet of S. costatum, such as 6-methyl-5-hepten-2-one (ether odor), and others are characteristic of T. isochrysis, such as 3-nonyne (cucumber, marine odor), 6-(E)-nonen-1-ol (green and fresh odor), and 4-ethylbenzaldehyde (aniseed odor). Moreover, the organoleptic qualities (odor, taste, and texture) of oysters are modified by the diet of microalgae.  相似文献   

Comparison of Coleoptera assemblages from a recently burned and unburned black spruce forests of northeastern North America     

Michel Saint-Germain  Pierre Drapeau 《Biological conservation》2004,118(5):583-592

Several insect groups have adapted to fire cycles in boreal forests, and can efficiently use new habitats created by fire. Our study aimed at producing a first characterization of post-fire Coleoptera assemblages of black spruce forests of eastern North America. For two years, we sampled Coleoptera using flight-interception traps in burned stands of contrasting age and structure in a 5097-ha wildfire and in neighbouring unburned mature stands. More than 40 species were exclusively captured in burned stands. Time elapsed since fire and proximity of unburned forests were the most significant parameters affecting Coleoptera assemblages. Stand age and structure had limited effects on assemblage structure; the Scolytid Polygraphus rufipennis Kirby was the only common species to clearly favor older stands. Fire-associated Coleoptera assemblages found in our study area were clearly distinct from those found in similar unburned stands; we should thus be conservative in our management approach concerning recently burned stands.  相似文献   

Soil properties and the macrofauna community in abandoned irrigated rice fields of northeastern Argentina     

Patricia J. Folgarait  Fabien Thomas  Thierry Desjardins  Michel Grimaldi  Ichiro Tayasu  Pierre Curmi  Patrick M. Lavelle 《Biology and Fertility of Soils》2003,38(6):349-357

This study compared soil physical, chemical, and biological characteristics between natural grassland and recently abandoned rice fields in order to identify those variables that might explain the observed increase of Camponotus punctulatus anthills in abandoned rice paddy fields from Northern Argentina. Mainly due to a reduction of macropores and mesopores, overall porosity decreased by around 6% and bulk density was about 7% greater, in the 0- to 10- and 10- to 20-cm layers of the abandoned rice fields. Carbon and nitrogen content from organic matter increased (29% and 41% respectively for the 0- to 20-cm horizon) during cultivation but decreased (38% and 24%) 2 years after the last rice harvest. Forty percent of natural grassland-organic matter and 30% of abandoned rice-organic matter mineralized in less than 2 years. There was a different community structure between the abandoned rice fields and the undisturbed natural grassland and only a 20.6% (i.e. only 19 species from a total of 92) overlap in species composition. The abundance of macrofauna was greater in abandoned rice fields (2,208 individuals m^–2) in comparison to natural grasslands (288 ind m^–2) due to higher densities of small earthworms and Camponotus punctulatus ants; however, the Shannon index showed lower values in comparison to natural grasslands. Earthworms and C. punctulatus in the abandoned rice fields showed a change in their ¹³C signature indicating a switch in diet from natural grassland organic matter (C4) to organic matter from rice (C3). Our results indicate that the effects of rice cultivation practices did not seem to produce any physical or trophic limitations to recolonization by the macrofauna. It seems that changes in overall soil conditions have favored a change in the construction behavior of C. punctulatus which, in combination with population increases, could explain the explosion in number of anthills.  相似文献   

Phosphorus Fractionation and Short-term Mobility in the Surface Sediment of a Polymictic Shallow Lake Treated with a Low Dose of Alum (Courtille Lake,France)     

van Hullebusch  Eric  Auvray  Franck  Deluchat  Véronique  Chazal  Philippe M.  Baudu  Michel 《Water, air, and soil pollution》2003,146(1-4):75-91

Lake Courtille was a polymictic eutrophic lake prone to large pH variations and sediment resuspension. Short term P release (96 hr) under laboratory resuspension conditions for two sedimentsample types, surface sediments which represent sediment accumulated over several years and trap sediments which representcurrent year sediment, was studied. The experiments were carriedout in oxic conditions at different pH values. According to phosphorus fractionation, Fe-bound-P, Al-bound-P and Organic-bound-P comprised the largest phosphorus pool (80% of Total Phosphorus). Phosphorus release was from the Fe-P, Al-P and organic fractions. These represent 35% of the total phosphorus content at pH 10. At circumneutral pH, in oxic conditions, a lower quantity of P was released (roughly 4% of total P sediment content) than at pH 10. The organic matter mineralization occurring at the end of summer can also influenceP release as illustrated by the difference in total phosphoruscontent between sediment samples of 2000 and of the last five years. This type of P release was observed in Lake Courtille. High soluble reactive phosphorus content was measured in the water column at the end of summer. Aluminium treatment was thus not efficient in preventing P release. Moreover, a higher alum dose was needed to reduce P content in the water column in order to decrease primary productivity and subsequent organic matter sedimentation.  相似文献   

Geographical distribution of Alzheimer's disease cases at birth and the geochemical profile of Saguenay-Lac-Saint-Jean/Québec,Canada (image project)     

Jean François Emard  Pierre Andre  Jean -Pierre Thouez  Jean Mathieu  Camil Boily  Michel Beaudry  Andree Cholette  Yves Robitaille  Remi Bouchard  Nicolas Daoud  Francine Veilleux  Denis Gauvreau 《Water, air, and soil pollution》1994,72(1-4):251-264

Accepting as founded the hypothesis of a multifactorial origin for the Alzheimer's disease (AD), we explore the possible links between the geographical distribution of AD cases according to their birth place and the geochemical profile of the Saguenay-Lac-Saint-Jean (SLSJ) territory in the province of Québec. The method used for factor analysis of correspondances (FAC) and another one based on the differences between the residential and municipal geochemical concentrations (DRMC) have been used for this purpose. The geochemical matrix of SLSJ relates the highest concentrations of nickel, copper and zinc to the sector surrounding the Jonquière municipality. Moreover, high concentrations of iron, lead and manganese were found in the northern sector of the Lac Saint-Jean. The DRMC method corroborates this strong correlation between iron, lead and manganese. Furthermore, these concentrations do not differ from the north-american geochemical standards. No single geochemical element seems to be associate with the spatial distribution of cases. It is, however, still possible that a certain synergistic effect between two or several elements could be implied in the development of the disease. According to the results of the soil analysis, there does not seem to be any association between the spatial distribution of cases and the concentration of aluminum, a chemical element that has been thought to be implied in the etiology of AD. These results are compared with those obtained by other workers in the micronesian islands, where abnormally high frequencies of amyotrophic lateral sclerosis and parkinsonism dementia have already been observed.  相似文献   

Cleavage products of lycopene produced by in vitro oxidations: characterization and mechanisms of formation     

Caris-Veyrat C  Schmid A  Carail M  Böhm V 《Journal of agricultural and food chemistry》2003,51(25):7318-7325

The aim of this study was to produce in vitro oxidation products of lycopene, which could be possible in vivo metabolites. An oxidation of lycopene with potassium permanganate gave a range of lycopene degradation compounds resulting from the oxidative cleavage of one or two carbon-carbon double bonds. Eleven apo-lycopenals/ones and six apo-carotendials were obtained and tentatively characterized by HPLC-DAD-MS. Apo-11-lycopenal and apo-8,6'-carotendial were isolated and characterized by (1)H NMR for the first time. Lycopene was submitted to an oxidation by atmospheric oxygen catalyzed by a metalloporphyrin, a model system of the active center of cytochrome P450 enzymes. (Z)-Isomers, monoxides, and cleavage compounds of (E)-lycopene were formed. We propose a mechanism of oxidation of lycopene by this system.  相似文献   

Soil microbial community characteristics along an elevation gradient in the Laguna Mountains of Southern California     

Harold P Collins  Michel A Cavigelli 《Soil biology & biochemistry》2003,35(8):1027-1037

We sampled soil at four sites in the Laguna Mountains in the western Sonoran Desert to test the effects of site and sample location (between or beneath plants) on fatty acid methyl ester (FAME) and carbon substrate ulilization (Biolog) profiles. The four sites differed in elevation, soil type, plant community composition, and plant percent cover. Soil pH decreased and plant density increased with elevation. Fertile islands, defined as areas beneath plants with greater soil resources than bare areas, are present at all sites, but are most pronounced at lower elevations. Consistent with this pattern, fertile islands had the greatest influence on FAME and Biolog profiles at lower elevations. Based on the use of FAME biomarker and principal components analyses, we found that soil microbial communities between plants at the lowest elevation had proportionally more Gram-negative bacteria than all other soils. At the higher elevation sites there were few differences in FAME profiles of soils sampled between vs. beneath plants. Differences in FAME profiles under plants among the four sites were small, suggesting that the plant influence per se is more important than plant type in controlling FAME profiles. Since microbial biomass carbon was correlated with FAME number (r=0.85,P<0.0001) and with FAME named (r=0.88,P<0.0001) and total areas (r=0.84,P<0.0001), we standardized the FAME data to ensure that differences in FAME profiles among samples were not the result of differences in microbial biomass. Differences in microbial substrate utilization profiles among sampling locations were greatest between samples taken under vs. between plants at the two lower elevation sites. Microbial substrate utilization profiles, therefore, also seem to be influenced more by the presence of plants than by specific plant type.  相似文献   

Diseases of sheep: Rue Jensen and Brinton L. Swift,Lea and Febiger,Philadelphia, PA, 2nd ed., 1982 US$ 35, 330 pp., ISBN 08121-0836-1     

Michel Rommel 《Veterinary parasitology》1982,11(4):381-382

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Physiology of reproduction and artificial insemination of cattle: Second edition. G.W. Salisbury,N.L. Vandemark and J.R. Lodge (Editors), W.H. Freeman and Co., San Fransisco,Calif., 1978, 798 pp., 203 illustrations,hard cover US $ 32.50, ISBN 0-7167-0025-5     

Michel Courot 《Livestock Production Science》1980,7(1):101-102

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