The N-Terminal Region of the Readthrough Domain Is Closely Related to Aphid Vector Specificity of Soybean dwarf virus

ABSTRACT It has been speculated that the N-terminal half of the readthrough domain (RTD) encoded by open reading frame 5 of Soybean dwarf virus (SbDV) is related to the vector specificity. To further investigate this hypothesis, transmissibility via aphids was tested on 17 SbDV isolates and comparisons of the deduced amino acid sequences of the coat protein (CP) and other proteins encoded by the RTD were made between these isolates. Isolates were distinguished into four strains: YS, causing yellowing in soybean and transmittable by Aulacorthum solani; DS, causing dwarfing and transmittable by A. solani; YP, causing yellowing and transmittable by Acyrthosiphon pisum; and DP, causing dwarfing and transmittable by A. pisum. Phylogenetic analysis showed that the trees for the CP and the C-terminal half of the RTD sequences contained clusters of isolates of the same symptom type, whereas the tree for the N-terminal half of the RTD contained clusters of isolates of the same aphid vector type. These results agreed with our previous data of the complete nucleotide sequences of four SbDV isolates, and strongly indicated a close relationship between the N-terminal half of the RTD amino acid sequences and aphid transmission specificity of SbDV.     

Hypertrophic cardiomyopathy in a mixed breed cat family

A spayed female mixed cat (case 1) and its female offspring, the result of a pairing between case 1 and its male sibling, were diagnosed with hypertrophic cardiomyopathy (HCM). A pedigree survey revealed that the prevalence of HCM was at least 12.5% in the family, which was considered to be significantly higher than that in a hospital-based population (approximately 1.6%). Thus, this finding seems to support the suspected occurrence of familial HCM in this group of related cats.     

An immunohistochemical study of endocrine cells in the abomasum of vagotomized calf

The effect of thoraco-vagotomy on the distribution and frequency of chromogranin-, serotonin-, somatostatin- and gastrin-immunoreactive cells in the abomasum of the calf were investigated by immunohistochemistry. Calves were vagotomized at 1 week old and sampled 2 and 4 weeks later. The endocrine cells generally decreased in number in vagotomized calves as compared to non-operated control calves. However, the detailed responses of endocrine cells to vagotomy varied depending on the endocrine cell type, region of gastric mucosa, and period after vagotomy. The present result suggests that the vagus nerve has an influence on the intrinsic regulatory system by endocrine cell control in the ruminant abomasum.     

Changes in platelet life span in dogs with mitral valve regurgitation

Platelet life span was measured in dogs with experimentally-induced mitral regurgitation (MR) by using an in vitro whole-blood biotinylation technique to evaluate the effects of shear stress induced by MR. Mitral regurgitation was created in healthy dogs by ablation of the mitral valve chordae tendineae. Mitral regurgitation was identified by auscultation and postoperative color Doppler echocardiography. Platelets were biotinylated. and derivatized blood was reinfused into the dogs. Biotinylated platelet disappearance was measured over time to determine platelet life span. Pre- and postablation platelet life span was compared in each dog. Platelet life span was shorter in dogs with experimentally induced MR. Shear stress from MR was postulated to shorten platelet life span. Alternations in platelet function and life span may contribute to the progression of cardiovascular disease in dogs with MR. Further studies are required to determine if platelet dysfunction is related to disease progression in these patients.     

Retrospective study of clinical complications occurring after arterial punctures in 111 dogs

The clinical complications occurring after 111 dogs had undergone arterial punctures were reviewed in relation to the dogs' breed, bodyweight, age, sex and underlying diseases. Seven of the dogs had moderate to extensive ecchymoses, which were significantly more common in dogs under 3.5 kg in bodyweight and in dogs with disorders of the cardiovascular system.     

The role of CD4(+) or CD8(+) T cells in the protective immune response of BALB/c mice to Neospora caninum infection

The role of CD4(+) or CD8(+) T cells in the immune response of BALB/c mice against Neospora caninum infection was examined by using anti-CD4 and/or anti-CD8 monoclonal antibodies (mAbs). Mice were intraperitoneally inoculated with anti-CD4 and/or anti-CD8 mAbs before and after infection with N. caninum and observed for 30 days after infection. Most of the anti-CD4 mAb-treated mice and all of the anti-CD4 and anti-CD8 mAbs-treated mice died within 30 days post-infection (p.i.). In contrast, 100% of PBS-treated mice and 70% of anti-CD8 mAb-treated mice survived more than 30 days. When compared with phosphate-buffered saline (PBS)-treated mice, the weight of mice treated with mAbs tended to decrease. From these results CD4(+) T cells, but not CD8(+) T cells, have an important role for protection of mice against N. caninum infection. Serum antibody levels to N. caninum in infected-mice treated with anti-CD4 mAb or a mixture of anti-CD4 and anti-CD8 mAbs were lower than those in the infected mice treated with anti-CD8 mAb or PBS. The mice treated with anti-interferon-gamma (IFN-gamma) mAb produced high antibody levels to N. caninum, but all mice died within 18 days p.i. These results indicated that IFN-gamma is an important cytokine for protection against N. caninum infection at the early stage of infection. However, since CD4(+) T cells against N. caninum were essential to the production of specific antibody, these antibodies might have important roles in host protection at the later stage of infection.     

Prevalence of Bartonella henselae, Bartonella clarridgeiae and the 16S rRNA gene types of Bartonella henselae among pet cats in Japan

The authors investigated bacteriologically the prevalence of Bartonella infection among 690 pet cats derived from 10 private animal hospitals in six cities (Sapporo, Hokkaido Prefecture; Sendai, Miyagi Prefecture; Joetsu, Niigata Prefecture; Fujisawa, Kanagawa Prefecutre; Kyoto, Kyoto Prefecture; Sanda, Hyogo Prefecutre) and 4 counties (Mishima, Osaka Prefecture; Hikawa, Shimane Prefecture; Aira, Kagoshima Prefecture; Shimajiri, Okinawa Prefecture) located from the north to the south of Japan. Bartonella species were isolated from 7.2% (50/690) of all the cats examined. No Bartonella species were isolated from the cats in Sapporo or Sendai. The isolation rate varied from 2% in Joetsu and Sanda to 20% in Shimajiri. Bartonella clarridgeiae was isolated from two of 50 cats in Kyoto, three of 50 in Mishima and one of 50 in Shimajiri, but not in cats from the other cities or counties. Though the cats of Joetsu, Fujisawa, Kyoto, Sanda, Aira and Shimajiri were infected with either B. henselae or B. clarridgeiae, one of eight infected cats in Mishima was harboring both Bartonella species. Type I of 16S rRNA gene was the predominant type among the isolates of B. henselae, but only one isolate derived from Shimajiri was found to be of type II. Prevalence of B. clarridgeiae and the 16S rRNA gene type of B. henselae among cats in Japan was demonstrated for the first time in this investigation.     

The quality and maturation of bitch oocytes recovered from ovaries by the slicing method

Oocytes were recovered from bitch ovaries at various stages of the estrous cycle by the slicing method. The proportion of Grade A oocytes (darkly pigmented and surrounded in part, or whole, by dense layers of cumulus cells) were counted. Only Grade A oocytes were cultured in TCM199 supplemented with 5% fetal calf serum for evaluation of meiotic competence. There were no significant differences in the total number of oocytes or the proportion of Grade A oocytes that were recovered from bitches at various stages of the estrous cycle. Only 11% of the oocytes reached metaphase II (MII) at 72 hr after initiation of maturation culture. However, the proportions of oocytes reaching MII did not increase with culturing for up to 120 hr.     

Geographical variation of mandible size and shape in the Japanese wild pig (Sus scrofa leucomystax)

The mandibles of the Japanese wild pigs (Sus scrofa leucomystax) from various geographical locations, which have been stored in the University of Tokyo and National Science Museum, Tokyo were examined. The mandibles from northern localities were larger in size than those from southern localities. The Oita population was significantly smaller than the Honshu populations. The Mie population was smaller than the Hyogo population in length from the angle of the mandible. In the multivariate analysis, the Kyushu populations could be obviously distinguished from the Honshu populations in the principal component charts. However, each Honshu population did not show the locality-specific distribution of the principal component plots.