Extensive polymorphism of ABO blood group gene: three major lineages of the alleles for the common ABO phenotypes

Polymorphism of the ABO blood group gene was investigated in 262 healthy Japanese donors by a polymerase chain reactions-single-strand conformation polymorphism (PCR-SSCP) method, and 13 different alleles were identified. The number of alleles identified in each group was 4 for A¹ (provisionally called ABO*A101, *A102, *A103 and *A104 according to the guidelines for human gene nomenclature), 3 for B (ABO*B101, *B102 and *B103), and 6 for O (ABO*O101, *O102, *O103, *O201, *O202 and *O203). Nucleotide sequences of the amplified fragments with different SSCP patterns were determined by direct sequencing. Phylogenetic network analysis revealed that these alleles could be classified into three major lineages, *A/*O1, *B and *O2. In Japanese, *A102 and *13101 were the predominant alleles with frequencies of 83% and 97% in each group, respectively, whereas in group O, two common alleles, *O101 (43%) and *O201 (53%), were observed. These results may be useful for the establishment of ABO genotyping, and these newly described ABO alleles would be advantageous indicators for population studies.     

IgE-mediated 14C-serotonin release from rat mast cells modulated by morphine and endorphins

The formaldehyde method was used to examine the interaction of PGE₁ with morphine, β-endorphin and Met-enkephalin on rat mast cells by their effects on IgE-mediated ¹⁴C-serotonin release. PGE₁ (2×10^?8?2×10^?5 M) caused a dose-related inhibition of the mediator release 1 min after an antigen challenge, and morphine (3×10^?7?3×10^?5 M) reversed this PGE₁ effect dose-dependently and stereospecifically; naloxone (2×10^?4 M) antagonized this action of morphine. β-Endorphin (3×10^?7?10^?5 M) and Met-enkephalin (3×10^?6?10^?4 M) mimicked this morphine action dose-dependently and were antagonized by naloxone (2×10^?4 M). These results suggest that morphine and endorphins modulate immunological mediator release from rat mast cells through opioid receptors.     

Synthesis and evaluation of N-alkyl-S-[3-(piperidin-1-yl)propyl]isothioureas: High affinity and human/rat species-selective histamine H3 receptor antagonists

S-Alkyl-N-alkylisothiourea compounds containing various cyclic amines were synthesized in the search for novel nonimidazole histamine H₃ receptor (H₃R) antagonists. Among them, four N-alkyl S-[3-(piperidin-1-yl)propyl]isothioureas 18, 19, 22, and 23 were found to exhibit potent and selective H₃R antagonistic activities against in vitro human H₃R, but were inactive against in vitro human H₄R. Furthermore, three alkyl homologs 18–20 showed inactivity for histamine release in in vivo rat brain microdialysis, suggesting differences in antagonist affinities between species. In addition, in silico docking studies of N-[4-(4-chlorophenyl)butyl]-S-[3-piperidin-1-yl)propyl]isothiourea 19 and a shorter homolog 17 with human/rat H₃Rs revealed that structural differences between the antagonist-docking cavities of rat and human H₃Rs were likely caused by the Ala122/Val122 mutation.     

Some Properties and Characterization of Rice Seed Hemagglutinin

The phytohemagglutinin of rice seed has been purified by a sequence of steps involving fractionation with ammonium sulfate and successive chromatography on DEAE-and eMcellulose and finally gel filtration on Bio-Gel P-100. The purified rice seed hemagglutinin was shown to be homogeneous by electrophoresis on polyacrylamide gel and its molecular weight was 10,000, calculated from both the Ve/Vo value of gel filtration on Bio-Gel P-100 and the sum of the individual constituents (amino acids, sugars and metals). In addition to amino acid, the rice seed hemagglutinin contained 26.8% covalently bound carbohydrate which was identified and quantitated by gas chromatography of the acetylated alditols. Glucose was the predominant sugar with lesser amounts of glucosamine, xylose, and mannose also being present. And the rice seed hemagglutinin contained 1 g atom of calcium per molecule. The molecular weight of the rice seed hemagglutinin is smallest compared with some of phytohemagglutinins isolated from leguminous seeds and other plant sources. The rice seed hemagglutinin has the blastogenetic activity for human peripheral lymphocytes as well as Phaseolus vulgaris phytohemagglutinins or concanavalin A, jack bean hemagglutinin.     

Mechanism of Action of Showdomycin

The effect of showdomycin on the syntheses of deoxyribonucleotides from various pyrimidine and purine derivatives was studied in cell-free systems from E. coli.

The formations of deoxycytidine phosphates, deoxyuridine phosphates, deoxyguanosine phosphates and deoxyadenosine phosphates from the corresponding ribonucleoside diphosphates were all inhibited by low concentrations of showdomycin. The formation of deoxythymidine phosphates from dUMP was also very susceptible to the antibiotic. These inhibitory actions of showdomycin could be reversed by a sulfhydryl compound (mercaptoethanol) but not by nucleosides, in contrast to a previous finding that the inhibitory action of this antibiotic on the cell growth was reversed by compounds belonging to both of these groups.

N-Ethylmaleimide (NEM), a thiol reagent which has a structure related to the aglycone moiety of showdomycin, was also found to be a potent inhibitor of both the reduction of CDP and the methylation of dUMP as showdomycin. A mercurial thiol reagent, p-chloromercuribenzoic acid (PCMB), however, was found to be inactive against the methylation of dUMP although the salvage synthesis of dUMP was inhibited by low concentrations of this reagent.

The formations of deoxythymidine phosphates and of deoxyuridine phosphates from their respective pyrimidine bases and a deoxyribosyl donor were quite resistant to showdomycin.     

Mechanism of Action of Showdomycin

¹⁴C-Labelled showdomycin was rapidly taken up by Escherichia coli K-12 cells. The showdomycin uptake was highly temperature dependent, sensitive to azide and N-ethyl-maleimide, but was only partially inhibited by treatment with high concentration of iodoacetic acid.

The uptake of showdomycin was inhibited by a wide variety of nucleosides but not by purine and pyrimidine bases, nucleotides, ribose or ribose-5-phosphate. The inhibition of showdomycin uptake by adenosine was of a competitive type.

Since nucleosides inhibited the uptake of showdomycin but did not facilitate its efflux, they must play a role of inhibitors to the entry of the antibiotic into cells.

Removal of extracellular showdomycin by washing, or inhibition of its subsequent entry into cells by the addition of nucleosides or sulfhydryl compounds resulted in a rapid decrease in the intracellular level of the antibiotic during subsequent incubation.