Many hereditary disorders in dogs have equivalents in humans and thus attract attention as natural animal models. Breed predisposition to certain diseases often provides promising clues to explore novel hereditary disorders in dogs. Recently, cases of gastrointestinal (GI) polyps in Jack Russell Terriers (JRTs) have increased in Japan. In 21 affected JRTs, polyps were found in either or both the stomach and colorectum, with a predilection for the gastric antrum and rectum. Multiple polyps were found in 13 of 21 examined dogs, including 5 dogs with both gastric and colorectal polyps. Some dogs were found to have GI polyps at an early age, with the youngest case being 2.3 years old. Histopathologically, 43 of 46 GI polyps (93.5%) were diagnosed as adenomas or adenocarcinomas. Immunohistochemical analysis revealed cytoplasmic and nuclear accumulation of β-catenin in the tumor cells. As in the case of human patients with familial adenomatous polyposis, all examined JRTs with GI polyps (n = 21) harbored the identical heterozygous germline APC mutations, represented by a 2-bp substitution (c.[462A>T; 463A>T]). The latter substitution was a non-sense mutation (p.K155X) resulting in a truncated APC protein, thus suggesting a strong association with this cancer-prone disorder. Somatic mutation and loss of the wild-type APC allele were detected in the GI tumors of JRTs, suggesting that biallelic APC inactivation was involved in tumor development. This study demonstrated that despite differences in the disease conditions between human and dog diseases, germline APC mutation confers a predisposition to GI neoplastic polyps in both dogs and humans.

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An interconversion system between imidazolium and imidazolinium has been proposed for the first time. Imidazolium and imidazolinium cations exhibit different reactivity due to the difference in the aromaticity and charge localization structure, which is successfully controlled by means of photoirradiation in the present system. A 4,5-dithiazolylimidazolium salt was prepared and studied as a new class of photochromic materials modulating electrostatic interactions and chemical reactivities. The photochromic 4,5-dithiazolylimidazolium showed reversible photoconversions between imidazolium open-form and imidazolinium closed-form upon successive irradiation with UV and visible light. The imidazolinium closed-form exhibited characteristic solvato- and ionochromisms in which the absorption maximum shifted by more than 80 nm depending on the solvent polarity and counteranions, whereas the imidazolium open-form showed no such solvent-dependent property. Because the corresponding nonionic 4,5-dithiazolylimidazole also did not exhibit the solvent-dependent absorption profile both in open- and closed-forms, the appearance of these chromisms in imidazolinium closed-form was attributed to the change in the extent of ionic interaction, which was brought about by the photoconversion of imidazolium to imidazolinium. The photoderived strong ionic interaction of imidazolinium with counteranion was further applied to the photocontrolled nucleophilic reaction system. Whereas the imidazolium open-form was inert to nucleophiles such as sodium methoxide, the imidazolinium closed-form was reactive to the nucleophilic reaction, demonstrating a photogated reaction system.

The dynamics of photoexcited carriers in standard TiO 2 photocatalytic powders has been studied by investigating the time decay and temperature dependence of the photoluminescence. A biexponential decay curve in a time-resolved signal suggests that there are different formation processes of the self-trapped exciton states. The peak position of the luminescence spectrum shifted to a higher energy at room temperature. On the basis of these experimental results, we propose a relaxation model of photoexcited carriers.

Toxigenic Corynebacterium ulcerans is a zoonotic pathogen that produces diphtheria toxin and causes a diphtheria-like illness in humans. The organism is known to infect and circulate among dogs, which can then transmit it to humans. Furthermore, previous studies have found that C. ulcerans is carried by wild animals, including game animals. In the present study, we tested hunting and companion dogs for the presence of toxigenic C. ulcerans and succeeded in isolating the bacterium from a hunting dog. Moreover, several hunting dogs had serum diphtheria antitoxin titers that were higher than the titers required for protection in humans, suggesting a history of exposure to toxigenic Corynebacterium strains. Notably, ribotyping, pulsed-field gel electrophoresis and tox gene sequencing demonstrated that the isolate from the hunting dog clustered with previously characterized C. ulcerans strains isolated from wild animals, as opposed to groups of isolates from humans and companion dogs. Interestingly, the wild animal cluster also contains an isolate from an outdoor breeding dog, which could have formed a bridge between isolates from wild animals and those from companion dogs. The results presented herein provide insight into the mechanism by which the zoonotic pathogen C. ulcerans circulates among wild animals, hunting and companion dogs, and humans.