System L amino acid transporters LAT1 and LAT2 are the members of SLC7 amino acid transporter family. They link to their ancillary protein 4F2hc (4F2 heavy chain) to form heterodimeric complexes. We have examined the mRNA expression by Northern blot and quantitative PCR and the protein localization by immunohistochemistry in the rat gastrointestinal tract. LAT2 and 4F2hc were colocalized in the basolateral membrane of duodenum, jejunum and ileum, suggesting that LAT2 with 4F2hc is functioning as a basolateral exit transporter and responsible for the transepithelial transport of amino acids. They were densely present in the epithelial cells toward the tip of villus, whereas their immunoreactivity became faint in the epithelial cells surrounding the crypt. LAT2 and 4F2hc were also colocalized in the plasma membrane of gastric parietal cells. These observations are consistent with the previous report on mice. In this study, we report for the first time the immunolocalization of LAT1 in the epithelia of gastrointestinal tract. In small intestine, LAT1 immunoreactivity was localized intracellularly in the supra-nuclear region of cytoplasm of the epithelial cells. LAT1 immunostaining was stronger in the epithelial cells lining the crypt of Lieberkuhn, whereas it was barely detectable in the epithelial cells at the tip of villus. In stomach, similar to small intestine, LAT1 immunostaining was densely detected intracellularly in the supra-nuclear region of the surface mucous cells lining the foveola. It became faint in the epithelial cells of the gastric glands. Because system L amino acid transporters, particularly LAT1, are proposed to play important roles in the pathogenesis of various diseases, the localization of these transporters in the rat gastrointestinal tract examined in the present study would provide basis for the understanding of their involvement in diseases and pathological conditions by using various gastrointestinal disease models established in rats.

View full abstract

A clinical memory test, the Wechsler Memory Scale-Revised (WMS-R), was used to study the memory of 20 high-functioning individuals with pervasive developmental disorder in order to compare the memory function between autistic disorder and other pervasive developmental disorders. First, subjects were divided into 3 groups (autistic disorders; asperger disorders; and pervasive developmental disorders not otherwise specified), and memory function was assessed based on WMS-R memory indicators. The results confirmed significant main effects in verbal memory, general memory and delayed recall. All 3 indicators were significantly worse for autistic disorders than for the other two groups. Results were analyzed based on the characteristics of each indicator, and the basis of autistic disorders was concluded to be low verbal memory affecting general memory and delayed recall. Also, using WMS-R, the relationship between the time slip phenomenon and memory function was investigated. The 3 groups displayed no significant differences in incidence of the time slip phenomenon. Furthermore, the relationship between the time slip phenomenon and memory indicators was examined, showing that the higher the delayed recall, the greater the likelihood of the time slip phenomenon, while the higher the verbal memory, the lower the likelihood of the time slip phenomenon. This finding supports the clinical notion that the time slip phenomenon is associated with pervasive developmental disorders and is closely involved with language impairment.

View full abstract

The expression patterns of neural cell adhesion molecule (NCAM), N- and R-cadherin during retinal regeneration of the adult newt were investigated by immunohistochemical analysis. These molecules which are known to be crucial factors for neural development were expressed throughout the retina before retinectomy. None of the molecules was detected at three weeks after retinectomy except for N-cadherin expression in the ciliary marginal zone (CMZ). R-cadherin expression, but not NCAM and N-cadherin, was restored to its original level at six weeks after surgery when retinal regeneration was completed based on the retinal morphology. NCAM expression in the nerve fiber layer was kept weak and N-cadherin expression was limited in the outer segment of photoreceptor cells and in the CMZ. According to these results, it was suggested that retinal regeneration was incomplete in terms of cell-cell interaction. Functional analysis of the regenerating retina would be required in future.

View full abstract

We performed the shotgun cloning to isolate novel sRNAs from an RNA fraction of about 60-80 nucleotides (nt) in stationary phase of Escherichia coli. After cDNA cloning, we performed dot blot hybridization with tRNA-specific oligo probes to eliminate cDNA clones derived from tRNAs. DNA sequencing and BLAST analysis showed that six clones and one clone 6H57 mapped in untranslated regions and an intergenic region, respectively, were obtained together with the known sRNAs, RyeB, RdlA, SokB and 6S RNA. We found that the 6H57 was expressed transiently in the 6 day-cultured early stationary-phase cells as a — 60 nt novel sRNA by Northern analysis. The strategy used in this study could be simple and efficient to isolate novel sRNA from bacterial cells.

View full abstract