Characterization of the hydroxycarboxylic acid receptor 2 in cats.

The hydroxycarboxylic acid receptor 2 (HCA2) belongs to a family of nutrient-sensing receptors that bind ß-hydroxybutyrate, an alternative fuel source produced during a negative energy balance. The HCA2 receptor has not been identified or characterized in cats. Therefore, the following were the objectives of this study: (1) identify the feline HCA2 receptor protein sequence and compare against known human and rodent sequences, (2) determine tissue distribution and relative expression in lean, healthy cats, and (3) demonstrate in vitro functionality in feline adipose tissue. Tissues (n = 6) and primary adipocytes (n = 4) were collected from lean, healthy, female cats. The published genomic sequence for cats was used to design primers for polymerase chain reaction isolation of HCA2. Relative tissue distribution was evaluated using reverse transcriptase-polymerase chain reaction with RNA isolated from 9 different tissues (spleen, pancreas, lymph node, jejunum, kidney, liver, heart, and subcutaneous and abdominal adipose tissue). Receptor function was evaluated in primary feline adipocyte culture, and changes were compared with basal lipolysis. The in silico predicted feline HCA2 protein sequence exhibited 83.1% and 86.5% amino acid similarity to human and mouse sequences, respectively. The feline HCA2 receptor is predominantly expressed in adipose tissue and spleen. Exposure of feline adipocytes to niacin, a pharmacologic ligand of HCA2, inhibited lipolysis to a similar degree as insulin, a potent lipolytic inhibitor. In conclusion, the feline HCA2 receptor is similar to human and murine receptors in sequence, distribution, and functionality. By gaining a better understanding of the HCA2 receptor in cats, we will be able to better manage feline patients.

Detection of pathogenic leptospires in animals by PCR based on lipL21 and lipL32 genes.

Efficacy of primers capable of amplifying conserved outer membrane protein (OMP) genes i.e., lipL21 and lipL32 of Leptospira strains was tested for rapid and early diagnosis of the leptospirosis using a polymerase chain reaction (PCR). These OMP genes were found to be conserved in various leptospiral serovars viz., Canicola, Pomona, Icterohaemorrhagiae, Pyrogenes, Sejroe, Grippotyphosa, Ballum and Tarassovi as PCR products of 561 bp and 756 bp were obtained by PCR employing lipL21 and lipL32 based primers, respectively, in all these serovars. Absence of such amplicons in DNA extracted from Pasteurella, Campylobacter and Brucella confirmed the specificity of the primers. Serum and tissue samples collected from cattle, buffaloes and experimentally infected guinea pigs and calves were subjected to PCR using above primers as well as conventionally used primers G1/G2. All the sera and tissue samples, whether field samples or collected from experimentally infected animals, found positive for G1/G2 specific PCR were also positive for lipL21 and lipL32 specific PCR. The present study indicated that lipL21 and lipL32 based primers could be used for PCR based diagnosis of leptospirosis. Since G1/G2 primers are known not to amplify the DNA of Grippotyphosa, the use of primers employed in the present study could have an additional advantage in detection of cases of the disease.