At the final maturation process red blood cells (RBC) are enucleated, becoming unable to synthesize nucleic acids as well as proteins. RBCs survive approximately 120 days in circulation using glucose as the sole energy source. Most crucial RBC functions depend on ATP to sustain physiological homeostasis. It is thus quite important that generation of ATP by glycolysis and replenishing of adenine nucleotide pools by the reaction, which is catalyzed by adenylate kinase (AK1). In turn, ribosomal RNA is degraded during remodeling of reticulocytes, and pyrimidine ribonucleotides become unnecessary for RBC viability. Thus they should be dephosphorylated by pyrimidine 5'-nucleotidase (P5N-I) and finally transported outside RBCs. There have been reported that hereditary deficiency of AK1 and P5N-I may cause shortened RBC life span, i.e. hemolytic anemia. In this review, we summarize physiological importance of these enzymes, which are involved in ribonucleotides metabolism during RBC maturation.
Jean Baptiste de Lamarck (1744-1829) maintained that characteristics that were acquired during an organism's lifetime are passed on to its offspring. This theory, known as Lamarckian inheritance, was later completely discredited. However, recent progress in epigenetics research suggests it needs to be reexamined in consideration of DNA methylation. In this article, I summarize our observations, which support Lamarckian inheritance. Initial experiments indicate that (1) artificially induced demethy-lation of rice genomic DNA results in heritable dwarfism, and (2) cold stress induces extensive demethy-lation in somatic cells of the maize root. Based on these results, I propose the hypothesis that traits that are acquired during plant growth are sometimes inherited by their progeny through persistent alteration of the DNA methylation status.
We have determined the complete nucleotide sequence of the plastid (149, 705bps), and the nucleotide sequence of the smallest chromosome (422, 021bps of chromosome I) of the unicellular red alga Cyanidioschyzon merolae. Fragments of other chromosomes have been also sequenced, altogether covering 1, 313, 748bps. Both the process of this determination, and the determined sequences of the plastid and chromosome I are reported in this paper. The sequence of chromosome I does not have a telomere repeat at either end. Lines of evidence indicate that the undetermined parts are short, -500bps each.
Pierisin-1 is a 98kDa protein known to induce apoptosis in various human carcinoma cell lines with a very wide range of IC50 values. Among those, the cervical carcinoma HeLa cells are the most sensitive, showing IC50 value of 0.043ng/ml. In the present study, we found that the LD50 value for pierisin-1 was around 5μg/kg body weight on intraperitoneal injection into female BALB/c mice. To examine whether this novel protein has anti-cancer activity against HeLa cells in vivo, cells were inoculated intraperitoneally into 6-week-old BALB/c nu/nu female nude mice on the first day and an intraperitoneal injection of pierisin-1 at a dose of 3μg/kg was given 24h after tumor cell inoculation. Thereafter, animals were sacrificed at day 80 and tumor weight was measured. Tumors were formed in all ten mice inoculated with HeLa cells and the mean tumor weight was 1.16g±0.18g per mouse. In mice inoculated with HeLa cells and treated with pierisin-1, the mean tumor weight was 0.56g±0.21g per mouse, and its value was significantly lower and no tumors were found in three of ten mice tested. Our results indicate that pierisin-1 has anti-cancer activity in vivo.