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1.
Phenolic compounds are ubiquitous in plant foods, and they have been reported to have multiple biological effects. This study investigates the ability of derivatives of hydroxybenzoic and hydroxycinnamic acids to influence the development of ciprofloxacin resistance in the antibiotic-sensitive strain Salmonella enterica subsp. enterica serovar Typhimurium. We have found that cinnamic acid and its hydroxy derivatives increase the frequency of mutations leading to ciprofloxacin resistance in comparison with spontaneous mutagenesis. Derivatives of hydroxybenzoic acid showed no or very little effect. Interestingly, gallic acid caused only phenotype resistance but not arising of mutant strains. Vanillic acid decreased spontaneous mutation frequency, leading to resistance not only to ciprofloxacin but also to tetracycline and gentamicin, and also decreased mutation frequency induced by 3-(5-nitro-2-furyl)acrylic acid, sodium azide, and hydrogen peroxide leading to ciprofloxacin resistance.  相似文献   
2.
Soluble proteins of 25 helminth species of the classes Trematoda, Cestoidea and Nematoda, were separated by disc electrophoresis using polyacrylamide gel columns. Differences between the species were investigated on the basis of Rm values of the bands. Protein spectra were complemented by the detection of lipoproteins and glycoproteins and by identification of LDH, SHD, peroxidase, esterase and alkaline phosphatase. On the basis of comparison of protein spectra of parasitic worms belonging to three taxonomic classes it was found by means of numerical taxonomy that individual classes are characterized by a certain number of proteins of the same migration properties.  相似文献   
3.
The protective effect of Enterococcus faecium EF55 in chickens challenged with Salmonella enterica serovar Enteritidis phage type 4 (SE PT4) was assessed. The antibacterial effect on the bacterial microflora in the small intestine in relation to white blood cell count, phenotyping of peripheral blood and intestinal lymphocytes, functional activity of lymphocytes and phagocytes and mucin quantitation were investigated. Day-old chicks (85) were randomly divided into four groups. The probiotic group (EF) and Salmonella + probiotic group (EFSE) received E. faecium EF55 (109 CFU – 3 g/group/day) for 21 days. The Salmonella group (SE) and EFSE group were infected with Salmonella Enteritidis (108 CFU in 0.2 ml PBS) in a single dose per os on day four of the experiment. The control group chicks (C) were fed a commercial diet without added bacteria. Supplementation of EF55 in the diet of the chickens in the EFSE group, challenged with S. Enteritidis, caused the density of the intestinal mucin layer to increase significantly in non-specific regions (duodenum and jejunum), but decrease significantly in target regions (caeca) for S. Enteritidis. Probiotic treatment also appeared to result in a significantly higher number of lymphocytes in peripheral blood and a tendency to increase CD3, CD4, CD8, and IgM positive cells 3 days post-infection with S. Enteritidis. The results demonstrated an antibacterial effect and suggested that EF55 had a moderating effect on intestinal mucin production and leukocytic response in the early phase of S. Enteritidis infection.  相似文献   
4.
Tetracapsuloides bryosalmonae (Myxozoa: Malacosporea) is the causative agent of proliferative kidney disease (PKD), which affects both wild and farmed salmonid fish. The objective of this study was to outline differences in susceptibility to PKD in different salmonid species, hybrids and breeding lineages. Susceptibility to T. bryosalmonae infection was established based on cumulative mortality, pathological findings and detection of T. bryosalmonae in the kidney using immunohistochemistry and molecular methods. Determination of pure and hybrid individuals of different species in the genus Salvelinus, and dissimilarity of rainbow trout lineages, was performed using traditional polymerase chain reaction (PCR) and microsatellite analyses. Rainbow trout displayed higher disease severity compared with brook trout and Alsatian charr. Moreover, the results indicated differences in infection susceptibility, not only among different salmonid species but also among different lineages of charr and rainbow trout. Our study indicated that some salmonid species and even different lineages of the same species are more suitable for farming under PKD pressure.  相似文献   
5.
On the basis of FAO/WHO tolerance recommendations, slaughtered pigs were divided into groups with gamma-HCH residues ranging from 0.5 to 2.0 mg per kg and with DDT residues ranging between 0.5 and 5.0 mg per kg in fat. Groups with negative residue findings were formed for control. Some parameters of the biological value of lard were determined in pig back fat. The presence of DDT and gamma-HCH residues did not change the melting and congelation points of lard. The acid number was higher by 31%, the saponification number dropped by 2.6%, the iodine number by 7.6%, the level of palmito-oleic acid by 16%, linoleic acid by 15% and linolenic acid by 40% due to the presence of DDT residues in lard. In the lard containing gamma-HCH residues the acid number increased by 42%, the saponification number decreased by 3.6%, the number of 8.1%, the level of palmito-oleic acid by 14%, linoleic acid by 18% and linolenic acid by 30%. It has been inferred from the results that the presence of DDT and gamma-HCH residues in the organism of a pig reduces the biological value of lard owing to the probable alteration of fat metabolism.  相似文献   
6.
Water, Air, & Soil Pollution - This study was conducted to evaluate the environmental fate processes of the herbicide (4-chloro-2-methylphenoxy)acetic acid (MCPA) in agricultural soils in the...  相似文献   
7.
After 1989, the use of potassium (K) mineral fertilizers in the Czech Republic dropped from ~55 kg K ha?1 to a mean rate of ~6.5 kg in the last decade. In order to test alternative solutions for K fertilization, the trioctahedral mica mineral zinnwaldite (8% K), orthoclase (10% K) and waste mica from Cínovec (Kru?né Hory Mts/Erzgebirge, Czech Republic), consisting primarily of zinnwaldite, were applied as the only K sources for spring barley. The minerals were treated in three different types of high-energy mills under different working conditions. Application rates in the range 139–820 mg K kg?1 were tested in quartz sand cultures. In all treatments, plant growth, total plant biomass and the K content in the plant tissues increased in the order zinnwaldite > waste mica > orthoclase. K fractionation and K plant uptake were significantly influenced by the milling method used. The effect of 195 mg K kg?1 as zinnwaldite on K uptake from K-depleted soils was positive; however, it was smaller than in sand cultures because of the relatively high content of non-exchangeable K in the soils. Direct use of waste mica as a K fertilizer is limited by the increased fluorine and heavy metal content.  相似文献   
8.
9.
In a pilot experiment, bullocks were given diet with a sodium monensinate supplement as the Rumensin preparation. The dose of the supplement was 125 mg per head/day and the medicated feed was given to the bullocks for 14 months. The daily weight gain of the tested bullocks increased by 3.85% and feed consumption decreased by 7.12%. The meat of the ten bullocks examined (m. longissimus dorsi) showed no statistically significant changes in the basic chemical composition as compared with the meat of ten control bullocks. In the tested group the content of hydroxyproline in meat decreased by 35.14% (from 0.12 to 0.08 g per 100 g of fresh tissue - p less than 0.05). The content of glycine decreased by 8.82% (from 3.63 to 3.31 g per 100 g of dry matter - P less than 0.01). The content of alanine decreased by 5.86% (from 5.12 to 4.82 g per 100 g of dry matter - P less than 0.05). As to essential amino acids, the content of valine in the meat of the tested bullocks increased by 4.76% (from 3.99 to 4.18 g per 100 g of dry matter - P less than 0.05). Sodium monensinate exerted a favourable influence on weight gains and nutrient conversion in the bullocks. It had no effect on the basic chemical composition and no marked influence on the content of amino acids, except hydroxyproline and, particularly, essential amino acids in the meat of the tested bullocks. A reduction in the content of hydroxyproline signalizes higher-value proteins.  相似文献   
10.
The effect of application of omega-3 polyunsaturated fatty acids (omega-3 PUFA) on intestinal colonization by Lactobacillus paracasei and on cellular immunity has been investigated in gnotobiotic pigs. The administration of polyunsaturated fatty acids positively affected the adhesion of Lactobacillus paracasei to the jejunal mucosa of gnotobiotic piglets. When compared to the control group, the number of Lactobacillus paracasei adhering to the jejunal mucosa was by 12% higher in piglets of the experimental group (5.10 log 10/cm2 vs. 4.55 log 10/cm2). The respective counts of Lactobacillus paracasei adhering to the ileal and colonic mucosa of 28 day old gnotobiotic piglets reached 4.45 and 5.05 log 10/cm2 in group C and 4.44 and 4.95 log 10/cm2 in group E. Omega-3 PUFA supplementation increased the phagocytic activity of neutrophils by almost 100% on day 28 of life as well as the subpopulations of lymphocytes (CD8) in the peripheral blood of germ-free piglets on day 21 of life. Our results indicate that the action of probiotics in the gut may be modulated by dietary PUFA. The stimulatory effect of PUFA upon adhesion of lactobacilli could be used for enhancing the effectiveness of probiotics in inhibiting digestive tract pathogens.  相似文献   
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