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Biomedical subjects

Kaoru Komoriya

Publications and source records attributed to Kaoru Komoriya.

4 recordsLinked to original sources
PubMed2005

Fertility of bitches in which estrus was prevented with implantations of chlormadinone acetate for four years.

The recurrence of estrus and fertility after removal of a subcutaneous chlormadinone acetate implant (CMA-I) administered to prevent estrus for 4 years, was investigated in 8 female dogs and the results compared with those for 4 untreated female dogs (control group). The sex hormones present during the estrous cycle were also investigated. There were no significant differences in the estrous cycle after removal of the implant between the CMA-I-treated group and the control group. However, although conception was achieved after mating and no uterine diseases developed in the control group, only 5 (4 dogs, 41.7%) of the 12 cases (6 dogs) in which mating took place at the second to fourth estrus after the removal of CMA-I resulted in pregnancy in the CMA-I-treated group. Furthermore, 6 (75.0%) of the 8 dogs in the CMA-I-treated group developed uterine diseases including pyometra or hydrometra. There were no significant differences in plasma progesterone, LH and prolactin levels between the non-pregnant and pregnant dogs in the CMA-I-treated group or control group. These results suggest that long-term implantation of CMA-I affects fertility after the implant is removed.

Animals↗
PubMed2003

Helical structure of the needle of the type III secretion system of Shigella flexneri.

Gram-negative bacteria commonly interact with animal and plant hosts using type III secretion systems (TTSSs) for translocation of proteins into eukaryotic cells during infection. 10 of the 25 TTSS-encoding genes are homologous to components of the bacterial flagellar basal body, which the TTSS needle complex morphologically resembles. This indicates a common ancestry, although no TTSS sequence homologues for the genes encoding the flagellum are found. We here present an approximately 16-A structure of the central component, the needle, of the TTSS. Although the needle subunit is significantly smaller and shares no sequence homology with the flagellar hook and filament, it shares a common helical architecture ( approximately 5.6 subunits/turn, 24-A helical pitch). This common architecture implies that there will be further mechanistic analogies in the functioning of these two bacterial systems.

Bacterial Proteins↗
PubMed2002

Identification and localization of flagellins FlaA and FlaB3 within flagella of Methanococcus voltae.

Methanococcus voltae possesses four flagellin genes, two of which (flaB1 and flaB2) have previously been reported to encode major components of the flagellar filament. The remaining two flagellin genes, flaA and flaB3, are transcribed at lower levels, and the corresponding proteins remained undetected prior to this work. Electron microscopy examination of flagella isolated by detergent extraction of whole cells revealed a curved, hook-like region of varying length at the end of a long filament. Enrichment of the curved region of the flagella resulted in the identification of FlaB3 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and N-terminal sequencing, and the localization of this flagellin to the cell-proximal portion of the flagellum was confirmed through immunoblotting and immunoelectron microscopy with FlaB3-specific antibodies, indicating that FlaB3 likely composes the curved portion of the flagella. This could represent a unique case of a flagellin performing the role of the bacterial hook protein. FlaA-specific antibodies were used in immunoblotting to determine that FlaA is found throughout the flagellar filament. M. voltae cells were transformed with a modified flaA gene containing a hemagglutinin (HA) tag introduced into the variable region. Transformants that had replaced the wild-type copy of the flaA gene with the HA-tagged version incorporated the HA-tagged version of FlaA into flagella which appeared normal by electron microscopy.

Amino Acid Sequence↗