Yusaku Watanabe

Hemotropic mycoplasma infection in wild black bears (Ursus thibetanus japonicus)

This is the first report on Mycoplasma infection in wild bears. We report a novel hemotropic Mycoplasma (also called hemoplasma) detected in a free-ranging black bear (Ursus thibetanus japonicus) in Japan. We then used real-time PCR to look for hemoplasma DNA in blood samples collected from 15 bears and found that eight (53%) were positive. Among these eight PCR samples, seven showed a melting temperature of around 85.5°C, while the remaining one showed a single peak at 82.26°C. Almost the entire region of the 16S rRNA gene as well as the 16S-23S rRNA intergenic transcribed spacer (ITS) region from the sample that showed a melting temperature of 82.26°C was successfully amplified by means of end-point PCR. The nucleotide sequences of the 16S rRNA gene and the ITS region were then determined and compared with those of authentic Mycoplasma species. Our examinations revealed the presence of a novel hemoplasma in Japanese black bears.

Acidic environments induce differentiation of Proteus mirabilis into swarmer morphotypes

Although swarmer morphotypes of Proteus mirabilis have long been considered to result from surfaced‐induced differentiation, the present findings show that, in broth medium containing urea, acidic conditions transform some swimmer cells into elongated swarmer cells. This study has also demonstrates that P. mirabilis cells grown in acidic broth medium containing urea enhance virulence factors such as flagella production and cytotoxicity to human bladder carcinoma cell line T24, though no significant difference in urease activity under different pH conditions was found. Since there is little published data on the behavior of P. mirabilis at various hydrogen‐ion concentrations, the present study may clarify aspects of cellular differentiation of P. mirabilis in patients at risk of struvite formation due to infection with urease‐producing bacteria, as well as in some animals with acidic or alkaline urine.

Genetic variation in the C-terminal domain of arginine vasotocin receptor in avian species

Arginine vasotocin (AVT) is a neurohypophysial hormone that plays an essential role in various social behaviours. We investigated the degree of polymorphisms in the C-terminal domain of the AVT V2-type receptor (AVT2R) among avian species to determine the mechanism by which genetic polymorphisms in the neuropeptide receptor may contribute to different levels of signal transduction. In passerine birds, AVT2R was characterised by 2 variable regions, both of which were managed by insertion/deletion (indel); however, indels were rarely found in other avian taxa. The presence or absence of deletions in passerines largely affected the properties of the predicted palmitoylation sites at the proximal part of the C-terminal tail. Moreover, we detected intraspecific polymorphisms in estrildid finches based on the number of tri-amino acid (GHQ/EHQ/EHR) repeats in another variable region. Our results indicate that amino acid substitutions and length variation at the C-terminus may impact subsequent signal transduction and affect behavioural traits in wild birds.