Synthesis and cloning of cDNA of the expressed msp2 gene copies of anaplasma marginale

The previous data indicated that major surface protein-2 [MSP2] gene of A. marginale Florida isolate is represented by a multigene family and distributed throughout the genomic DNA of A. marginale. This work studied the cloning of the expressed copies of MSP2 gene. The technique of staining and separating of A. marginale RNA was improved. The formaldehyde gel electrophoresis, northern blotting, hybridization using nonradioactive labeled probe [Dig-Labeled MSP2] and chemiluminescent detection method were used. Specific MSP2 mRNA of A. marginale was isolated from total RNA using hybridization selection. The recovered MSP2 mRNA was used as a template for cDNA synthesis using r and om hexamers as a primer. Restriction mapping and Southern blot hybridization of the 13 cDNA clones showed different cDNA inserts of molecular sizes ranged from 0.48 to 1.2 kbp, sequence analysis of the 3- and 5-ends of all 13 cDNA clones were done using silver sequence [DNA sequencing system] [Promega] using T7 and Sp6 primers

Salmonellosis in newborn calves in a closed dairy farm

An acute outbreak of calf salmonellosis occurred in a cow dairy farm during June 1991, where 7 calves died in acute course. Dead calves showed symptoms of diarrhea and enteritis and PM lesions of distended gallbladder, necrotic focci in the liver and swollen lymph nodes. Salmonella organisms were isolated from five cases. Fecal sample from 194 calves less than 3 months of ages were collected and examined. In calves with age ranged 9-27 days salmonella was recovered from 14 cases with an incidence of 7.2%. Serologically, all isolated strains proved to be Salmonella carrau