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231.
232.
233.
B Hofírek P Horín M Granátová M Machatková J Franz I Svoboda J Blecha 《Veterinární medicína》1986,31(3):129-140
A trial was performed with heifers at the age of six to seven months. The animals were experimentally infected with the lymphocytes of a virus-productive donor. Infection was produced in all the nine cases, as demonstrated by means of the positive syncytial test. As indicated by the results of the trial, the antibodies to the enzootic bovine leucosis virus (BLV) were produced soon after experimental infection. A high sensitivity of the serum-neutralization test and the ELISA method was demonstrated in this connection: by these methods, the antibodies were identified already two to three weeks after experimental infection whereas by the immunodiffusion test they could be detected only after five weeks. Twenty-four animals were exposed to natural contact infection. Within 270 days of the trial, the disease after contact was recorded only in one heifer out of the four that were in close contact with the experimentally infected animals. In this case, as compared with experimental infection, the antibodies were produced much later--after 85 to 93 days. Leucosis was recorded in none of the remaining animals. The reasons why such a favourable result was obtained were the thorough disinfection of the stables after blood collections and the strict observance of the aseptic conditions. The results of experimental infection in three cows were identical with those obtained in young cattle. In the experimentally infected dairy cows, antibodies in milk were determined by the ELISA method. As found, in milk the antibodies to BLV appear two to three weeks later than they do in serum. The ELISA method of BLV antibody detection can be used for the identification of infected animals in herds where enzootic bovine leucosis occurs. 相似文献
234.
235.
M. HEDDELL-COWIE 《Fisheries Management and Ecology》2005,12(2):137-142
Abstract The body mass distributions and variations in abundance of the spring and autumn catches of Atlantic salmon, Salmo salar L., were compared between fisheries above and below the confluence of the rivers Tweed and Teviot, Scotland. Significant differences between the distributions were found over three periods, one in spring and two in autumn, when salmon catches were high. Correlations were found between abundance trends for periods when distributions were similar or dissimilar. Abundance of salmon returning to the River Teviot was proportional to the main river. However, its population structure differed when abundances were high, suggesting different survival strategies. It appears that changes in the numbers returning to the river were resultant of changes in the marine rather than freshwater environment. 相似文献
236.
The prophylactic effect of ivermectin treatment of calves, three weeks after turnout, on gastro-intestinal helminthiasis 总被引:1,自引:0,他引:1
M Eysker 《Veterinary parasitology》1986,22(1-2):95-103
In two grazing experiments carried out in 1982 and 1983 the prophylactic effect on gastro-intestinal helminthiasis of a single ivermectin treatment of calves 3 weeks after turnout was studied in animals which were turned out early on contaminated pasture and in calves which were turned out late on mown pasture. A single ivermectin treatment 3 weeks after early turnout did not prevent heavy helminth infections. However, such single treatment of calves 3 weeks after a late turnout on mown pasture appears to be a promising way of preventing heavy infections. Late turnout on mown pasture without anthelmintic treatment was not enough to prevent heavy infections. Ivermectin treatment was more effective against Ostertagia spp. than against Cooperia spp. There was no effect on the faecal egg output of Nematodirus helvetianus. Predominantly due to the dry summer, infections were lighter in 1983 than in 1982. These lower infections, and possibly also a delay in the onset of inhibition and differences in helminth strains, may explain the lower proportion of inhibited development in Ostertagia spp. in 1983 than in the comparable groups in 1982. 相似文献
237.
Experimental trials on the use of radioimmunoassay for the detection of leptospiral antigens in urine 总被引:1,自引:0,他引:1
Trials were conducted on the use of the solid phase radioimmunoassay (RIA) to detect leptospires or their antigens in simulated urine samples. The procedure was relatively simple to perform and appeared to be specific in detecting certain numbers of leptospiral organisms or their antigens in experimentally prepared samples. With this technique, it was possible to examine individual or pooled urine samples for the presence of leptospires within half a day. This technique may be of value for the detection of leptospiruric animals if the sensitivity of the technique could be further increased. Suggestions for the improvement of the procedure are discussed. 相似文献
238.
Molecular structure of troponin C from chicken skeletal muscle at 3-angstrom resolution 总被引:19,自引:0,他引:19
M Sundaralingam R Bergstrom G Strasburg S T Rao P Roychowdhury M Greaser B C Wang 《Science (New York, N.Y.)》1985,227(4689):945-948
The x-ray structure of chicken skeletal muscle troponin C (TnC), the Ca2+-binding subunit of the troponin complex, shows that the protein is about 70 angstroms long with an unusual dumbbell shape. The carboxyl and amino domains are separated by a single long alpha helix of about nine turns. Only the two high-affinity Ca2+-Mg2+ sites of the COOH-domain are occupied by metal ions resulting in conformational differences between the COOH- and NH2-domains. These differences are probably important in the triggering of muscle contraction by TnC. Also the structure of TnC is relevant in understanding the function of other calcium-regulated proteins, in particular that of calmodulin because of its strong similarity in amino acid sequence. 相似文献
239.
Veterinary Research Communications - 相似文献
240.
M H Raibert 《Science (New York, N.Y.)》1986,231(4743):1292-1294
Symmetry plays a key role in simplifying the control of legged robots and in giving them the ability to run and balance. The symmetries studied describe motion of the body and legs in terms of even and odd functions of time. A legged system running with these symmetries travels with a fixed forward speed and a stable upright posture. The symmetries used for controlling legged robots may help in elucidating the legged behavior of animals. Measurements of running in the cat and human show that the feet and body sometimes move as predicted by the even and odd symmetry functions. 相似文献