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A novel approach to control Boophilus microplus is to disrupt the physiological function of an endogenous myokinin receptor of this tick that was previously cloned in our laboratory . To test the hypothesis that this myokinin receptor might be a suitable target for development of a novel acaricide , this target was validated by immunological disruption . A mixture of peptides , corresponding to the sequence of the extracellular loops of this receptor which were synthesized and linked to a carrier protein , was injected into Hereford cattle to induce an immunological response . Immunological tests (ELISA ) were developed to test the sera of these animals for antibody titers . The data were analyzed using a randomized block split plot design and were compared between the control (calves numbers 407 , 408 , 427 , 436 , and 438 ) and peptide -injected calves (calves numbers 417 , 420 , 421 , 426 , and 435 ) . A gradual increase of antibody production was observed with the peptide -injected calves with bleed 4 showing the highest absorbances . Control calves and peptide -injected calves with high antibody titers were challenged with approximately 20 ,000 tick larvae at the USDA Cattle Tick Research laboratory . The tick challenge test determined that disruption of the receptor function produces a detrimental effect on tick physiology (development , feeding and reproduction ) by looking at percentage of molting , time of survivorship , number of ticks dropped , weight of fed females , weight of egg masses , and blood meal conversion . The results , which were analyzed by a contingency table and a 2 sample T -test , did not support the hypothesis that the sera ingested from the peptide -injected cattle would cause a detrimental effect on tick physiology . There was no statistical significance in the percentage of metanymphs molting from peptide -injected calves versus control calves (p = 0 .282 ) and in the time of adult survivorship . A statistical inference could be made about the number of ticks that dropped since four calves died of bovine babesiosis after the metanymphal collection . There was no statistical significance in the weight of fed females (p = 0 .061 ) , weight of egg masses (p = 0 .885 ) , and bloodmeal conversion (p = 0 .312 ) from peptide -injected calves versus control calves . |
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