We examined the anti-metastatic effect of 6-(methylsulfinyl)hexyl isothiocyanate (6-MITC) isolated from wasabi (Wasabia japonica MATSUM). Pulmonary micrometastasis was quantified using a dependable method to detect the human c-Ha-ras gene, which was carried in the tumor cell line. Mice belonging to the S-1 group were administered 6-MITC continuously for 35 days from the time of tumor cell inoculation, and S-2 group mice were administered 6-MITC for 21 days from the day of amputation. Oral administration of 200 μM 6-MITC solution was effective in preventing metastasis of the experimental tumor. In the S-1 group, 7 out of ten experimental mice have lungs carrying no detectable human c-Ha-ras gene. Amplified human c-Ha-ras bands were detected in only the lungs of three mice; in these, the metastatic indexes of the lungs were respectively 0.60, 0.70 and 0.90. In the S-2 group, the bands were detected in four lungs of 5 experiments, with the metastatic indexes of the lungs in the range 0.36–0.72. Starting the treatment at the time of tumor cell inoculation was more effective in preventing metastasis than beginning the treatment on the day of amputation.
During the response of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), methylation occurred at the Hpa II site of c-myc exon I, which is located downstream of the P1 initiation site, as evidenced by the assays of Hpa II-PCR. The Hpa II spite of the 5' flanking region did not undergo methylation. UV-irradiation also led to methylation in exon I. The extent of methylation increased depending on the dose of MNNG and UV. The results suggested that methylation takes place in transcriptionally active c-myc responsible for carcinogens and is caused by mechanisms different from that of alkylation in a specific CpG site. Possible contribution of methylation to less repair found in c-myc is discussed.
It was found that light accelerates the swelling of spinach chloroplasts suspended in a solution containing NaCl and Tris-HCl, and that, in about 60 min, the swollen chloroplasts begin to shrink rapidly. The volume of chloroplasts reached, on swelling, 270 per cent of the original volume on the average and then shrank to 17 per cent. The rate of swelling and the maximum volume were affected markedly by the tonicity of NaCl. NH4Cl did not affect the volume changes, while phenazine methosulfate accelerated the swelling remarkably. The relationship between photoshrinkage and this light-induced high-amplitude swelling was discussed.
Serum-free mouse embryo (SFME) cells, the astrocyte progenitor cells in the central nervous system (CNS), were exposed to 10 ng/ml leukemia inhibitory factor (LIF) and 10 ng/ml bone morphogenic protein 2 (BMP2) to induce differentiation, and expression of cell-type specific markers. Nestin, a marker of early neural lineage, βIII-tubulin, a marker of neuronal lineage, oligodendrocyte marker O4 (O4), a marker of oligodendrocytic lineage and glial fibrillary acidic protein (GFAP), a marker of astrocytic lineage, were analyzed. Characteristics of SFME cells, as a CNS progenitor, were identified and a possible mechanism, underlying SFME cell specification into an astrocytic lineage upon differentiation, was investigated. These markers were present, both at the initial proliferative phase and after induction of differentiation. GFAP expression increased strongly upon differentiation, while expression of the other markers changed very little. These results indicate that astrocytic differentiation is associated with the asymmetric production of these markers, rather than through induction of astrocytic markers.
The occurrence of natural hemagglutinins in the coelomic fluid of sea urchins, Anthocidaris crassispina, Pseudocentrotus depressus, and Hemicentrotus pulcherrimus, was reported.The coelomic fluid preparations from three species of sea urchin were found to have hemagglutinating activity against rabbit and human erythrocytes but not against mouse and sheep erythrocytes so far examined. Dog erythrocytes were sensitive to the coelomic fluids of A. crassispina and H. pulcherrimus. The coelomic fluids of P. depressus and H. pulcherrimus also agglutinated guinea pig erythrocytes.The hemagglutinins against rabbit erythrocytes from A. crassispina and P. depressus might be a protein or a protein-like substance and were heat-unstable and resistant to trypsin digestion, but not to bromelain, and were affected by 2-mercaptoethanol though the activity of the former was recovered when 2-mercaptothanol was removed. On the other hand, the hemagglutinin of H. pulcherrimus might be a large molecular, complicated carbohydrate, which was heat stable and resistant to trypsin, bromelain, 2-mercaptoethanol, and periodate.The hemagglutinating activity of the coelomic fluids was greatly enhanced by the addition of calcium but not magnesium, and the hemagglutination by them was not dependent on temperature. Inhibition tests with simple sugars on hemagglutinating activity of the coelomic fluids resulted in failure to determine the specificity of receptor sites for these hemagglutinins. In addition, the results of absorption test on the specificity of the hemagglutinin of sea urchin were discussed.
