The DNA colony hybridization test with the polynucleotide probe forVibrio parahaemolyticus toxR gene was performed. All 373 strains of V. parahaemolyticus gave positive results, and the strains belonging to four other Vibrio species including Vibrio alginolyticus gave weakly positive results, suggesting that toxR sequence variation may reflect the phylogenetic relationships of Vibrio species. We then established a toxR-targeted PCR protocol for the specific detection of V. parahaemolyticus.

Our pervious electron microscopic studies indicated that Merkel cells (MCs) in the gerbil palatine mucosa were polymorphic, possibly reflecting different function. In order to verify and extend this evidence, the shape of and the innervation to MCs in the palatine mucosa of six different species of rodents including the Mongolian gerbil and the rat were examined by immunohistochemistry and transmission electron microscopy. Immunohistochemistry using anti-cytokeratin 20 (CK20) antibody revealed that in the gerbil palatine mucosa, approximately half of MCs were dendritic. Confocal laser scanning microscopy after double labeling with anti-cytokeratin and anti-PGP 9.5 or anti-Na+/K(+)-ATPase beta 1 subunit antibodies indicated that most of the dendritic MCs (DMCs) in these mucosae were free of innervation. Electron microscopy showed that all species of rodents examined contained abundant dendritic MCs as well as roundish (oval to round) MCs (RMCs) with typical innervation. Secretory granules of the RMCs were usually concentrated at the synaptic site, whereas those of the DMCs tended to accumulate in the tips of the cytoplasmic processes and in the cytoplasm facing the basal lamina. Some MCs showed features intermediate between those of the RMC and DMC. These results indicate that MCs in rodent palatine mucosae are consistently polymorphic, and that DMCs may represent a distinctive subset with specific, presumably including endocrine and paracrine, functions different from those of RMCs.

Brain-enriched human FC96 protein shows a close sequence similarity to the Dictyostelium actin-binding protein coronin, which has been implicated in cell motility, cytokinesis, and phagocytosis. A phylogenetic tree analysis revealed that FC96 and two other mammalian molecules (p57 and IR10) form a new protein family, the coronin-like protein (Clipin) family; thus hereafter we refer to FC96 as ClipinC. A WD domain and a succeeding ␣-helical region are conserved among coronin and Clipin family members. ClipinC is predominantly expressed in the brain, and discrete areas in the mouse brain were intensely labeled with anti-ClipinC antibodies. ClipinC was also shown to bind directly to F-actin in vitro. Immunocytochemical analysis revealed that ClipinC accumulated at focal adhesions as well as at neurite tips and stress fibers. Furthermore, ClipinC was associated with vinculin, which is a major component of focal contacts. These results indicate that ClipinC is also a component part of the cross-bridge between the actin cytoskeleton and the plasma membrane. These findings and the previously reported function of coronin suggest that ClipinC may play specific roles in the reorganization of neuronal actin structure, a change that has been implicated in both cell motility and growth cone advance.Actin filaments in neuronal cells form a cortical framework that helps to localize membrane proteins, and F-actin dynamics has been implicated in directing neuronal outgrowth. Rearrangement of the actin cytoskeleton occurs in response to various stimuli such as soluble factors or attachment to a substratum (1, 2). The regulation of F-actin patterns involves actin polymerization and actin cross-linking. Factors regulating these processes communicate with the small G proteins of the Rho family (3) and the phosphatidylinositol metabolism system (4), both of which are triggered by extracellular cues through a variety of receptors.The Dictyostelium actin-binding protein coronin was first purified from an actin-myosin complex and was hypothesized to transmit signals from the membrane receptors to the cortical cytoskeleton (5). Coronin accumulates at the leading edges of moving cells and in crown-shaped extensions on the dorsal cell surface. The involvement of coronin in cell motility, cytokinesis, and phagocytosis, all of which depend on cytoskeletal rearrangement, has been demonstrated by use of a gene replacement mutant. In a mutant that lacks coronin, cell motility is reduced to less than half of the normal speed, and cytoplasmic cleavage in cytokinesis is impaired (6). Further, in the coronin null (cor Ϫ ) mutant, the rate of yeast uptake is reduced by about 70% (7). However, the distribution of actin filaments in cor Ϫ cells is similar to that in the wild-type ones (6).In this study, we found a novel candidate for an actin cytoskeleton-cortical membrane linking protein; this protein, ClipinC, is also the third member of a family of mammalian homologs of Dictyostelium coronin. The ClipinC transcript was predominantly expressed in th...

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