Distribution of zinc in the substantia nigra of rats treated with 6-hydroxydopamine

To study the relationship between tissue accumulation of Zinc (Zn) and neurodegeneration in the nigrostriatal dopaminergic pathway,⁶⁵Zn distribution in this pathway was examined after unilateral injection of 6-hydroxydopamine (6-OHDA) into the substantia nigra of rats. When⁶⁵ZnCl₂ was intravenously injected 4 days after treatment with 6-OHDA,⁶⁵Zn was concentrated in the ipsilateral substantia nigra 6 days after⁶⁵Zn injection. On the other hand, 19 d after treatment with 6-OHDA,⁶⁵Zn distribution in the ipsilateral substantia nigra was decreased to the level of the contralateral one. When NH₄ ⁹⁹TcO₄, which cannot go through the blood-brain barrier, was injected into rats 4 d after treatment with 6-OHDA,⁹⁹Tc was concentrated in the ipsilateral substantia nigra 30 min after⁹⁹Tc injection, but no longer detectable 6 d after injection. These results suggest that Zn is necessary for a repair process called replacement gliosis after the death of neurons and that excess Zn does not accumulate in the lesion after completion of the gliosis.     

Evolutionarily conserved promoter motifs and enhancer organization in the mouse gene encoding the IIB myosin heavy chain isoform expressed in adult fast skeletal muscle.

We have isolated the mouse gene for the MHC isoform expressed in adult type IIB (fast-contracting, glycolytic) skeletal muscle fibers, and determined the DNA sequence of the promoter region. This sequence represents the first example of a promoter for a gene encoding an adult-specific isoform of a mammalian skeletal MHC. The proximal 200 bp of the promoter contains several sequence motifs which are identical or very similar to homologous motifs found in the promoters of a family of chicken skeletal MHC genes. Of these, two novel AT-rich sequences may be important for regulation of the promoter. A second feature of the mouse IIB MHC promoter sequence concerns a number of sequence motifs located at ca. -1,000 bp which are organized in a similar fashion in the IIB MHC promoter and a homologous region of promoter of the mouse muscle creatine kinase gene.     

Cardiomyopathies and mitochondrial DNA mutations

Our former studies concerning mitochondrial DNA mutations were reviewed in this article. A 7.4 kb deletion between the D-loop and ATPase 6 genes was detected in myocardial tissue obtained at autopsy from patients with myocardial infarction, diabetes mellitus and also patients treated with adriamycin. A case with diabetes mellitus and hypertrophic cardiomyopathy is demonstrated which revealed a point mutation from adenine to guanine at position 3243 within tRNA_Leu(UUR).     

Formation of Valine in the Presence of Sodium Acrylate Monomer by Glutamic Acid Producing Bacteria

Glutamic acid producing bacteria accumulated a large amount of valine in the presence of the excess biotin, when sodium acrylate monomer (Na-AM) was added at the earlier phase of culture. Brevibacterium roseum ATCC 13825, particularly, accumulated the large amount of valine among bacteria tested and the conditions of valine accumulation by this strain were investigated.

The most effective addition time of Na-AM was at the earlier phase of logarithmic phase. The optimal concentration of Na-AM for the accumulation of valine was 1.0 per cent (v/v). Most effective nitrogen sources were the combination of 1.0 per cent urea and 0.2 per cent ammonium sulphate. The additions of Mn²⁺ and Fe²⁺ increased valine accumulation. By the excess concentration of biotin for growth, 20 μg/liter or more, did not affected valine accumulation, while the presence of the suboptimal condition of biotin for growth was not good for the formation of valine even in the presence of Na-AM. The accumulation of valine reached 9.0 mg/ml from 75.0 mg/ml of glucose in the presence of 50 μg/liter of biotin and 1.0 per cent (v/v) of Na-AM.

This strain possessed considerable activity of valine formation regardless of the addition of Na-AM and promoted the accumulation of valine by the addition of Na-AM.     

Synthetic studies on glycosphingolipids from the parasite Echinococcus multilocularis.

Novel neutral glycosphingolipids isolated from the metacestodes of Echinococcus multilocularis by Persat, may be expected to be involved in host-parasite interactions. We have synthesized these glycosphingolipid analogues containing 2-branched fatty alkyl residues in place of ceramide. The glycosylation of galactosyl donors 4 and 5 with each of the acceptors 2 and 11 in the presence of N-iodosuccinimide (NIS)/TfOH, and the glycosylation of fucosyl donor 13 with acceptors 12 and 20 in the presence of dimethyl(methylthio)sulfonium triflate (DMTST) gave the desired oligosaccharide derivatives at good yield. The fully per-O-acylated 2-(trimethylsilyl)ethyl glycosides 6, 15, 21, and 26 were converted to glycosylimidates 7, 16, 22, and 27, which were condensed with 2-(tetradecyl)hexadecanol and subsequently deacylated give four target glycosphingolipid analogues.     

Improved Technique for Identification and Enumeration of Methanogenic Bacterial Colonies on Roll Tubes by Epifluorescence Microscopy

Methanogenic fluorescent colonies can be clearly identified on roll tubes by using an epifluorescence microscope equipped with a × 2 objective. Methanogenic and nonmethanogenic colonies could be counted in roll tubes prepared from methanogenic enrichment cultures. Late-developing colonies appearing after 25 days of incubation were mainly methanogenic.