Surface functional properties of native, acid-treated, and reduced soy glycinin. 2. Emulsifying properties   总被引：8，自引：0，他引：8  

Wagner JR  Guéguen J 《Journal of agricultural and food chemistry》1999,47(6):2181-2187

Emulsifying properties of native and chemically modified soy glycinins were studied. The influence of ionic strength, protein sample composition and concentration, and assay conditions on the flocculation-creaming process and coalescence resistance was analyzed. Differences in these emulsifying properties were exhibited by native glycinins, which have a variable content of 4S, 11S, and 15S forms. Structure and functionality of native glycinin were modified by means of combined treatments: mild acidic treatments without heating or with heating at variable time and with or without disulfide bonds reduction. Modified glycinins presented different degrees of deamidation, surface hydrophobicity, and molecular mass. A slight enhancement of emulsifying stability at moderated deamidation degrees was observed. In different protein samples, a positive relationship between the flocculation-creaming rate constant and equilibrium oil volume fraction of emulsions with surface hydrophobicity was detected. A remarkable difference was observed between reduced and nonreduced samples, mainly with respect to behavior at low or high ionic strength.  相似文献   

Centimeter-scale variability in the chemistry of convective rains     

George H. Wagner  Kenneth F. Steele 《Water, air, and soil pollution》1994,72(1-4):9-18

A standard National Atmospheric Deposition Program (NADP) rain collection bucket was sectioned with 220 test tubes of 1.5 cm diameter. Eleven rains from thunderstorms were collected. Analyses were made for Ca, Na and K concentrations in the test tube liquids. The relative standard deviation (RSD), after correction for the analytical RSD, was 0 to 15% for Ca, 0 to 24% for Na, and 0 to 17% for K. Analytical RSD for Ca, Na and K determined from standards were, respectively, 5.4, 6.6 and 12%. Calculations indicate that the difference of 2 to 3 giant nuclei per test tube of calcite (Ca), sea salt (Na) and clay (K) would account for these different RSDs. Concentration ranges in the rains varied from 0.14 to 2.95 mg L^?1 for Ca, 0.024 to 0.23 mg L^?1 for Na, and 0.014 to 0.064 mg L^?1 for K. The area between the test tubes which was 40% of the total collector area provided a bottom sample which on average agreed within 1.3% of the average value of the test tubes.  相似文献   

The impact of harvester ants on decomposition, N mineralization, litter quality, and the availability of N to plants in the Mojave Desert     

Diane Wagner  Jeremy B. Jones 《Soil biology & biochemistry》2006,38(9):2593-2601

In arid areas of North America, nests of the seed-harvesting ant Pogonomyrmex rugosus tend to be elevated in mineral nitrogen and other soil nutrients relative to other microhabitats. We investigated the roles of decomposition, N mineralization, and plant nutrient uptake in maintaining high standing stocks of nutrients in P. rugosus ant nests. Decomposition rates of standard cellulose substrates placed on the surface of ant nests and other desert microhabitats suggest that conditions found in ant nests and bare areas are conducive to higher rates of decomposition than conditions under shrubs. In laboratory incubations of moist soil, net N mineralization rates were significantly higher in soil from ant nests than from bare areas and under two of three plant species. Net N mineralization rates measured in situ were much lower than those measured in laboratory incubations, but ant nest soil still exhibited higher rates at one of two sites. Litter collected from ant mounds, composed chiefly of seed chaff, was similar in N content to litter collected from underneath the dominant plant species, but had a significantly higher mean δ¹⁵N. Using this distinctive isotope signature as a tracer, we found no evidence that large perennial shrubs tap ant nests as a source of N. An invasive, annual grass species was significantly enriched in ¹⁵N, had higher leaf %N, and produced more seeds when growing on the mound than when growing several meters away; however P. rugosus nest surfaces are typically free of such annuals. We conclude that both high rates of nutrient cycling relative to other Mojave Desert microhabitats and low N utilization by the surrounding vegetation contribute to high standing stocks of mineral N in P. rugosus nests.  相似文献   

Surface functional properties of native, acid-treated, and reduced soy glycinin. 1. Foaming properties   总被引：4，自引：0，他引：4  

Wagner JR  Guéguen J 《Journal of agricultural and food chemistry》1999,47(6):2173-2180

Foaming properties of native and chemically modified glycinin were evaluated. Effects of ionic strength and glycinin composition and concentration on foam formation and stabilization were studied. Glycinin was modified by means of combined treatments: cold or hot acidic treatments, with or without later disulfide bridges reduction. Modified proteins obtained from glycinin present different degrees of dissociation, deamidation, and as consequence, varied surface hydrophobicity and molecular size. Parameters of forming and stabilizing of foam were correlated with both deamidation and dissociation degrees of modified and native glycinin samples. A positive relationship was observed between surface behavior and foaming properties of different protein species. Results show that dissociation, deamidation, and reduction have produced structural changes on glycinin (increased surface hydrophobicity, increased net charge, decreased molecular size) which enhance the adsorption and anchorage of proteins at the air-water interface and, consequently, improve the foam forming and stabilizing capacities.  相似文献   

The dispersal of Culicoides brevitarsis in eastern New South Wales and associations with the occurrences of arbovirus infections in cattle     

AL BISHOP  PD KIRKLAND†  HJ MCKENZIE  IM BARCHIA 《Australian veterinary journal》1996,73(5):174-178

Distributions of the vector Culicoides brevitarsis Kieffer (Diptera: Ceratopogonidae) (determined from light trap data) and 2 arboviruses (determined from seroconversions in sentinel cattle) were studied in eastern New South Wales in 1993–94. C brevitarsis was recorded progressively from endemic areas on the north coast, to Nowra on the south coast, and westward to Scone, in the Hunter Valley. C brevitarsis also survived through winter at Paterson, in the Hunter Valley. Its apparently focal reappearance in this marginal area had no obvious effect on the broad pattern of its progression or the dispersal of Akabane and bluetongue viruses. These viruses were first recorded from foci near Coffs Harbour, on the mid-north coast. Their first occurrences at different locations were associated with those of C brevitarsis, but not with each other. The viruses were found only within the recorded limits of the vector's distribution. Delays between the initial occurrence of C brevitarsis and first evidence of virus transmissions at locations ranged from 2 to 7 months. The delays decreased away from the points of focus and were negatively associated with the time of initial occurrence of the vector. Seroconversions to the viruses were related to the presence of C brevitarsis. However, the densities of C brevitarsis had no apparent effect on the initial numbers of cattle seroconverting to either virus. The results support the conclusion that the progressions of C brevitarsis and Akabane and bluetongue viruses were the result of gradual movements by the vector.  相似文献   

A third report of "golf ball disease" in an Amazon River dolphin (Inia geoffrensis) associated with Streptococcus iniae.     

Christopher J Bonar  Robert A Wagner 《Journal of zoo and wildlife medicine》2003,34(3):296-301

An Amazon River dolphin (Inia geoffrensis) developed a dermatologic syndrome characterized by the occurrence of slow-growing, nodular, s.c. abscesses. Initial biopsies, cultures, and cytologic analysis of needle aspirates from the abscesses indicated steatitis with probable secondary, gram-negative bacterial infection. Treatment with dietary vitamin E supplement and broad-spectrum antibiotics yielded minimal improvement. Subsequent cultures revealed Streptococcus iniae in addition to several gram-negative bacteria. Vigorous surgical management of the abscesses, including lancing, debridement, and irrigation, combined with antimicrobial therapy specific for Streptococcus and gram-negative organisms, and improvement of the animal's diet and environmental water quality led to gradual recovery. When the animal was ill, it demonstrated an inflammatory leukogram and transient uremia. Streptococcus iniae is a serious pathogen of aquacultured fishes and humans and should be included in the differential diagnosis of chronic dermatopathy in river dolphins. Specific antimicrobial therapy, excellent water quality, surgical management of abscesses, and adherence to sanitary protocols should be observed in cases of suspected S. iniae infection in dolphins.  相似文献   

A new dosing schedule for gentamicin in blood pythons (Python curtus): a pharmacokinetic study     

M Hilf  D Swanson  R Wagner  V L Yu 《Research in veterinary science》1991,50(2):127-130

Gentamicin is frequently used in the treatment of aerobic Gram-negative infections in reptiles. Pharmacokinetic data to ensure proper dosing are scant, especially for large snakes. A pharmacokinetic study of gentamicin was therefore conducted in four blood pythons. Snakes were given intramuscular injections of either 2.5 mg kg-1 or 3.0 mg kg-1 loading dose followed by 1.5 mg kg-1 at 72 and 96 hours. A linear pharmacokinetic relationship between gentamicin serum concentrations and time was demonstrated in each of the four snakes studied. Peak serum concentrations occurred six to 10 hours after injection and ranged from 4.6 to 8.9 micrograms ml-1. Half-life was variable and ranged from 32 to 110 hours. Total body clearance and apparent volume of distribution varied little between the individual snakes studied. There was no evidence of renal toxicity. For blood pythons a loading dose of 2.5 mg kg-1 followed by 1.5 mg kg-1 at 96 hour intervals is recommended. If higher concentrations are desired, a loading dose of 3.0 mg kg-1 followed by 1.5 mg kg-1 at 96 hours can be given. These dosing schedules will provide serum concentrations in excess of the minimum inhibitory concentrations for most aerobic Gram-negative bacilli that are pathogenic in snakes; gentamicin accumulation with subsequent renal dysfunction should not occur.  相似文献   

Experiments on resistance-lowering effect of urethane. II. The effect of urathan on vaccinia virus infection in mice following intracerebral virus application     

S Wagner  E Benndorf 《Archiv fuer experimentelle veterinaermedizin》1965,19(3):953-962

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Differential diagnosis of dysphagia in the horse     

P C Wagner  N W Rantanen  B D Grant 《Modern veterinary practice》1979,60(12):1029-1033

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Nasal-maxillary fibrosarcoma in young horses: a light and electron microscopic study     

B D Hultgren  W B Schmotzer  B J Watrous  O R Hedstrom  J A Schmitz  P C Wagner  A J Kaneps  J A Gallagher 《Veterinary pathology》1987,24(2):194-196

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