The complete nucleotide sequence (21,359 bp) of the mitochondrial DNA of the rhacophorid frog Rhacophorus schlegelii was determined. The gene content, nucleotide composition, and codon usage of this genome corresponded to those typical of vertebrates. However, the Rh. schlegelii genome was unusually large due to the inclusion of two control regions and the accumulation of lengthy repetitive sequences in these regions. The two control regions had 97% sequence similarity over 1,510 bp, suggesting the occurrence of concerted sequence evolution. Comparison of the gene organizations among anuran species revealed that the mitochondrial gene arrangement of Rh. schlegelii diverged from that of typical vertebrates but was similar to that of Buergeria buergeri. The positions of the tRNA-Leu(CUN) and tRNA-Thr genes were exchanged between Rh. schlegelii and B. buergeri . Based on parsimonious consideration and the basal phylogenetic position of B. buergeri , these genes seemed to have been rearranged in an ancestral lineage leading to Rh. schlegelii .

Recent advances made in the isolation, culture, and transplantation of defined populations of intrahepatic biliary epithelial cells and oval cells have permitted direct analysis of the functions, growth properties, and differentiation potential of these respective cell types in their untransformed or transformed states. This review provides a current and comprehensive examination of the various approaches that have been taken to isolate and culture intrahepatic biliary epithelial cells from normal and cholestatic liver and oval cells from preneoplastic liver. Emphasis is placed on comparing the phenotypic features and growth properties of these various biliary cell types in vitro as well as on describing their transplantation into ectopic tissue sites. In addition, the oval cell is evaluated in terms of its potential role as a ‘facultative stem cell’ during hepatocarcinogenesis.

Nucling is a novel apoptosis-associated molecule, which is involved with cytochrome c /Apaf-1/caspase-9 apoptosome induction following pro-apoptotic stress. In the present study, we show first that Nucling is able to interact with galectin-3. Galectin-3 is known to participate in many biological processes, including apoptotic cell death. Nucling was found to down-regulate the expression level of galectin-3 mRNA/protein. Nucling-deficient cells, in which galectin-3 expression is up-regulated, appeared to be resistant to some forms of pro-apoptotic stress as compared with wild-type cells. In addition, the preputial gland from Nucling-deficient mice expressed a significant level of galectin-3 and exhibited a high incidence of inflammatory lesions, indicating that Nucling plays a crucial role in the homoeostasis of this gland by interacting with the galectin-3 molecule and regulating the expression level of galectin-3. Up-regulation of galectin-3 was also observed in the heart, kidney, lung, testis and ovary of the Nucling-deficient mice. In order to confirm the functional interaction between Nucling and galectin-3, a well-documented candidate for the mediator of galectin-3 expression, NF-kappaB (nuclear factor kappaB), was investigated as well. Nucling was shown to interfere with NF-kappaB activation via the nuclear translocation process of NF-kappaB/p65, thus inhibiting the expression of galectin-3. Taken together, we propose that Nucling mediates apoptosis by interacting and inhibiting expression of galectin-3.

In this study we determined the complete nucleotide sequence (19,959 bp) of the mitochondrial DNA of the rhacophorid frog Buergeria buergeri . The gene content, nucleotide composition, and codon usage of B. buergeri conformed to those of typical vertebrate patterns. However, due to an accumulation of lengthy repetitive sequences in the D-loop region, this species possesses the largest mitochondrial genome among all the vertebrates examined so far. Comparison of the gene organizations among amphibian species ( Rana, Xenopus , salamanders and caecilians) revealed that the positioning of four tRNA genes and the ND5 gene in the mtDNA of B. buergeri diverged from the common vertebrate gene arrangement shared by Xenopus , salamanders and caecilians. The unique positions of the tRNA genes in B. buergeri are shared by ranid frogs, indicating that the rearrangements of the tRNA genes occurred in a common ancestral lineage of ranids and rhacophorids. On the other hand, the novel position of the ND5 gene seems to have arisen in a lineage leading to rhacophorids (and other closely related taxa) after ranid divergence. Phylogenetic analysis based on nucleotide sequence data of all mitochondrial genes also supported the gene rearrangement pathway.