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991.
992.
The pH0 and ZPC of two Hydiandepts were determined by potentiomettic titiation in NaCl and by ion adsorption measurements from NH4NO3, respectively. The decrease of pH, pH0, and ZPC due to drying was explained by the hydrolysis reaction. Partial drying, high organic matter content, and low Al2 O3 concentration in the surface soil were responsible for its low pH, pH0 and ZPC. The high pH0 of subsoils was attributed to the presence of amorphous aluminosilicates and mixed polymeric gels of Fe(III) and A1 with high water content. The significant decrease of nitrate adsorption due to dehydration is discussed in relation to the change in pH, pH0, ZPC, and surface area on drying. 相似文献
993.
Grain sorghum is often damaged by rain in the field and severely infected by grain mold, which includes Aspergillus infection and aflatoxin production. The objective of the study is to investigate the extent of aflatoxin production with Aspergillus infection in vitro in different sorghum genotypes with different pericarps, red, yellow, and white, the physical and chemical characteristics of grain during infection, and the changes in grain polyphenols and phytic acid in comparison to maize and groundnut. The physical characters and biochemical composition of sorghum grain contribute to make it less susceptible to Aspergillus infection and aflatoxin contamination compared to maize and groundnut. The lowest amounts of aflatoxin and ergosterol were observed in genotypes with red pericarp, whereas higher amounts of aflatoxin and ergosterol were found in white genotypes followed by maize and groundnut. All of the red genotypes differ in polyphenol composition and aflatoxin produced, showing resistance to mold damage. Another indication of resistance in red genotypes was the delayed peaking of aflatoxin production (9 days after infection). In red sorghum genotypes there was a significant, positive correlation existing between polyphenol content and aflatoxin produced at 3 and 6 days after infection, the r values being 0.589 and 0.513, respectively. The starch content decreased whereas the protein content in all sorghum genotypes increased during infection. Maximum phytic acid was observed in white sorghum genotypes. Phytic acid in yellow genotypes was found to have a significant negative correlation (r = -0.569) with aflatoxin produced. 相似文献
994.
Piergili Fioretti D Pasquali P Diaferia M Mangili V Rosignoli L 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2003,50(8):399-404
In this paper, a parasitological and serological study performed in three cows up to the fourth gestation is reported in order to clarify the extent of vertical propagation and, secondly, in which period of gestation the recrudescence of previous infection occurs. The cows selected for the study delivered healthy but congenitally infected calves in first pregnancy. The parasite was found, by biological tests in Swiss mice, in all the placentas of the three cows examined, during the three subsequent gestations, at calving. The parasite was found, at slaughtering, in the brains of all nine calves born clinically healthy from the three cows as well. The serological profile, performed at monthly intervals on serum of the cows, showed that IgG and IgM increased in the third trimester of gestation; this rise of antibodies was constantly observed during the three gestations and in all three cows. In the calves, the IgG titres increase after colostrum consumption and an IgM peak at birth, were indicative of a late infection. These findings, along with negative results obtained by a serological study conducted simultaneously on 38 cows housed in the same stable as the experimental animals and the negative results obtained in isolating parasite or antibodies from farm dogs, suggest that N. caninum infection can be maintained over several bovine generations and that recrudescing persistent infection, rather than a new infection, explains the Neospora infection of calves. 相似文献
995.
Rumen-protected choline administration to transition cows: effects on milk production and vitamin E status 总被引:1,自引:0,他引:1
Pinotti L Baldi A Politis I Rebucci R Sangalli L Dell'Orto V 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2003,50(1):18-21
We investigated the influence of rumen-protected choline (RPC) supplementation on milk production, lipid metabolism and vitamin E status in dairy cows receiving a silage-based diet. Twenty-six Italian Holstein multiparous cows were assigned by weight and average production in the previous lactation, to one of two groups: control (no RPC supplementation) and RPC (supplemented with 20 g/day rumen-protected choline chloride). Treatment began 14 days before expected calving and continued for 30 days after parturition. Choline administration significantly increased milk production during the first month of lactation and also the concentration (and total secretion) of choline in milk, but did not affect fat or protein concentrations in milk, or plasma levels of glucose, beta-hydroxybutyrate, cholesterol and non-esterified fatty acids (NEFA). However, around parturition, NEFA concentrations in plasma were lower in treated animals than in controls, suggesting improved lipid metabolism as a result of choline supplementation. Choline supplementation also increased alpha-tocopherol plasma concentrations, suggesting a novel aspect in dairy cows. 相似文献
996.
Faustini M Bronzo V Maffeo G Russo V Munari E Vigo D 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2003,50(9):466-469
Platelet count (PLT) mean platelet volume (MPV) and plateletcrit (PCT) were determined for 117 Landrace x Large White piglets aged 3-21 days; counts were performed with an automated blood cell counter (ABX Pentra 120). Reference values were estimated following the guidelines of the International Federation of Clinical Chemistry (IFCC) and the International Committee for Standardization in Haematology (ICSH). The calculated central 95% reference limits for PLT was 49.9-516.2 x 10(9)/1, for MPV 6.71-9.91 fl and for PCT 0.009-0.395%. When observations are divided into three age groups (about 1 week each) there is an increase in mean PLT count and PCT in 2-week piglets, and a decrease in MPV from the first to the third week of life. These reference values provide guidelines for interpreting for experimental and clinical observations, as well as for monitoring of the health status of similar aged piglets determined using automated impedance-light focusing methodology. 相似文献
997.
Abstract We examined 12 formalin-fixed paraffin-embedded feline skin tumours which had the histopathological features of fibropapillomas for the presence of papillomavirus (PV) DNA using touchdown polymerase chain recation (PCR), DNA sequencing and nonradioactive in situ hybridization. Nine of the tumours contained a 102-bp PCR product demonstrated using consensus PV primers that amplify a portion of the L1 gene. The nucleotide sequences are closely related, but not identical to that of ovine PV type 2, rabbit oral PV and reindeer PV. The deduced amino acid sequences had strong homologies with the major capsid protein L1 of deer PV, bovine papillomavirus (BPV) 1 and BPV 2, and European elk PV. Although PV antigens were not detected in any of the tumours by immunohistochemistry, PV DNA was demonstrated in individual mesenchymal cells or cell nests of 4/12 tumours by in situ hybridization. A nonproductive infection of mesenchymal fibroblast-like tumour cells with a papillomavirus would explain the lack of PV antigen expression and the absence of PV DNA in the hyperplastic epithelium. Because these tumours and their pathogenesis are similar to equine sarcoids, we suggest that they should be reclassified as 'feline sarcoids' instead of fibropapillomas. 相似文献
998.
ABSTRACT Logistic regression models for wheat Fusarium head blight were developed using information collected at 50 location-years, including four states, representing three different U.S. wheat-production regions. Non-parametric correlation analysis and stepwise logistic regression analysis identified combinations of temperature, relative humidity, and rainfall or durations of specified weather conditions, for 7 days prior to anthesis, and 10 days beginning at crop anthesis, as potential predictor variables. Prediction accuracy of developed logistic regression models ranged from 62 to 85%. Models suitable for application as a disease warning system were identified based on model prediction accuracy, sensitivity, specificity, and availability of weather variables at crop anthesis. Four of the identified models correctly classified 84% of the 50 location-years. A fifth model that used only pre-anthesis weather conditions correctly classified 70% of the location-years. The most useful predictor variables were the duration (h) of precipitation 7 days prior to anthesis, duration (h) that temperature was between 15 and 30 degrees C 7 days prior to anthesis, and the duration (h) that temperature was between 15 and 30 degrees C and relative humidity was greater than or equal to 90%. When model performance was evaluated with an independent validation set (n = 9), prediction accuracy was only 6% lower than the accuracy for the original data sets. These results indicate that narrow time periods around crop anthesis can be used to predict Fusarium head blight epidemics. 相似文献
999.
ABSTRACT Tomato race 3 (T3) strains of Xanthomonas campestris pv. vesicatoria are antagonistic in vitro to tomato race 1 (T1) strains of the bacterium. All T1 strains and 11 strains of other X. campestris pathovars tested were inhibited by T3 strains. Sensitivity of tomato race 2 (T2) strains was variable. No strains from other bacterial genera tested were inhibited. Cell-free filtrates from T3 strains were inhibitory to sensitive strains. The inhibitory activity of these filtrates was lost after treatment at temperatures above 80 degrees C and with selected protease enzymes. However, treatment with trypsin or DNase had no effect on their activity. Seven cosmid clones from a genomic library of a T3 strain were selected for their ability to consistently inhibit a sensitive indicator strain in plate assays. Southern hybridization analysis placed these into three bacteriocin (BCN)-producing groups designated BCN-A, BCN-B, and BCN-C. The BCN-like groups could be differentiated by variations in inhibitory spectra and levels of activity in plate assays. Mutations that inactivated expression of each BCN group individually in a wild-type T3 strain had inhibitory activity confirming that multiple BCNs are present in the T3 strain. T3 strains were inhibitory to a sensitive indicator strain in tomato leaf tissue, but this effect was observed only when T3 strains were applied in advance of the sensitive strain. BCN-A was the major BCN-like substance involved in the suppression of the sensitive indicator strain in tomato leaf tissues. 相似文献
1000.
ABSTRACT The root-knot nematode Meloidogyne incognita is a major pathogen of a range of important crops. Currently, control is typically achieved by the use of nematicides. However, recent work suggests that manipulating the ability of roots to slough off border cells, which then act as a decoy to the nematode, can significantly decrease damage to the roots. We investigated the attractiveness of border cells to M. incognita and the response of the nematode to border cells in close proximity. We found very limited attraction, in that nematodes did not preferentially alter direction to move toward the border cells, but a large and significant increase in nematode speed was observed once they were in the immediate vicinity of border cells. We discuss the results in the context of physical and biological mechanisms in relation to the control of pathogenic nematodes. 相似文献