Single nucleotide polymorphism in avian uncoupling protein gene is associated with thermoregulation in chicks

Avian uncoupling protein (av-UCP) is a key protein for thermoregulation in poultry. A single nucleotide polymorphism (SNP) in the av-UCP gene has been reported in chickens. The purpose of the current study was to clarify the association between this av-UCP gene mutation and thermoregulation in chickens. Wild and mutant type chicks for the av-UCP gene SNP (g. 1270 of the av-UCP gene exon 3 with C to T substitution and amino acid substitution) were exposed to high ambient temperature. Rectal temperature, radiation temperature on the body surface, and the expression of heat dissipation behavior (wing drooping and panting) during heat exposure were measured. In addition, oxygen consumption rate in the thermoneutral zone in wild and mutant type chicks was measured. Changes in wing temperature during heat exposure in wild-type chicks were lower than those in mutants. The latency of continuous wing drooping during heat exposure in wild-type chicks was shorter than in mutant chicks. It was also found that the SNP in the av-UCP gene caused reduced oxygen consumption. These results suggest that the av-UCP gene mutation affects thermoregulation, especially heat production, in chickens.     

Generation of Salmonella ghost cells expressing fimbrial antigens of enterotoxigenic Escherichia coli and evaluation of their antigenicity in a murine model

Salmonella Typhimurium ghost cells expressing K88ab, K88ac, K99, and FasA fimbriae of enterotoxigenic Escherichia coli (ETEC) in their envelopes were constructed. The genes encoding the fimbriae were individually cloned into an expression plasmid, pMMP81, carrying the asd gene, which was subsequently electroporated into the Δasd S. Typhimurium mutant. Plasmid pJHLP99, carrying the phiX174 lysis gene E, was also subsequently electroporated into the Salmonella mutant. The presence of the individual fimbriae on the ghost cells was examined by Western blot analysis. Forty BALB/c mice were equally divided into 2 groups of 20 mice each. Group A mice were intramuscularly vaccinated with a mixture of the 4 ghost cells expressing the individual fimbriae. The group B mice were inoculated with sterile phosphate-buffered saline as a control. The antigen-specific serum IgG concentrations were significantly higher in group A than in group B from week 2 until week 6 after inoculation. In addition, the antigen-specific IgA concentrations in fecal samples were significantly higher in group A than in group B at week 2 after inoculation. A large difference between the groups in the number of antigen-specific IgA-secreting cells in the small intestine was observed by immunohistochemical study. Also, the splenic lymphocyte proliferative responses were significantly greater in group A than in the control mice. These results suggest that vaccination with our Salmonella ghost cells can induce both humoral and cell-mediated immune responses and that the increased number of antigen-specific IgA-secreting cells in the small intestine may be correlated with the elevated fecal IgA immune response.     

Responses of dogs to dietary omega-3 fatty acids

Long-chain omega-3 fatty acids from fish oil and other marine sources appear to be capable of modifying inflammatory and immune responses in dogs. Information is provided on the capacity of dogs to metabolize omega-3 fatty acids and the effects of omega-3 fatty acids on skin and coat, inflammatory responses, and neurologic development in puppies.     

Relatedness of cytotoxins from geographically diverse isolates of Moraxella bovis

To determine whether amino acid sequence variation exists in the Moraxella bovis (M. bovis) cytotoxin (MbxA) from geographically diverse M. bovis isolated in the United States, mbxA was amplified and sequenced. The MbxA deduced amino acid sequence from M. bovis originally isolated in California, Washington, North Carolina, and Georgia, as well as reference strains of M. bovis isolated at the National Animal Disease Laboratory, Ames, IA, USA, all encoded a nearly identical 927 amino acid protein. MbxA from two of the four California isolates (SFS 9a and SFS 100a) differed from all other isolates at two sites at which the polar amino acids glutamine (position 666) and asparagine (position 823) were replaced by ionized amino acids glutamic acid and aspartic acid, respectively. Rabbit antiserum to the expressed carboxy terminus (amino acids 590-927) of MbxA from M. bovis (Tifton I) neutralized the hemolytic activity of SFS 9a and SFS 100a. The M. bovis cytotoxin appears to be conserved amongst geographically diverse isolates of M. bovis from the USA. Antiserum against the carboxy terminus of MbxA common to the majority of isolates neutralized the hemolytic activity of two strains with a divergent MbxA deduced amino acid sequence. Vaccines against IBK that incorporate MbxA as antigen may offer protection against geographically diverse strains of M. bovis.