Complete deficiency of AMP deaminase in human erythrocytes

Four individuals with complete absence of erythrocyte AMP deaminase have been discovered. The subjects appear to be perfectly healthy and there was no evidence of hemolysis. The deficiency was found only in erythrocytes and as expected, mononuclear cells and platelets showed normal level of activity. The activities of all the other purine metabolizing enzymes that were tested were normal. The deficiency is inherited as an autosomal recessive trait.     

Chloroplast aggregation during the cold-positioning response in the liverwort Marchantia polymorpha

Journal of Plant Research - Under low-light conditions, chloroplasts localize along periclinal cell walls at temperatures near 20 °C, but they localize along anticlinal cell walls near...     

Fine structural and histochemical study of lingual taste organs of Rana catesbeiana (Anura: Ranidae) transplanted to liver

Autologous tongues were transplanted onto the liver of the anuran Rana catesbeiana, specimens of which were sacrificed at intervals from 6 hr to 5 months after transplantation. Light and electron microscopy as well as histochemistry disclose that the grafts start to organize into cysts after 14 days. The taste organs occur in all grafts irrespective of the age of the graft. All surviving taste organs exhibit intense adenosine triphosphatase (ATPase) activity and contain fluorescent basal cells of the usual type. Ultrastructurally, the taste organs are composed of three distinct types of cells that lack nerves. The taste and basal cells retain the characteristic dense-core granules in their cytoplasm through the experimental periods. The present results suggested that the taste organs of Rana can survive ectopically in the liver for up to 5 months.     

Mechanism of Anucleate Cell Production in the oriC-Deleted Mutants of Bacillus subtilis

We constructed oriC-deleted mutants of Bacillus subtilis byintegrating the minimal replication region of plasmid pLS32into the proA (115°), spoIIIJ (360°) and thrS (256°)loci of the chromosome, respectively. All three mutants producedanucleate cells and the DNA/protein ratio was lower than thatof the wild-type strain when grown in nutrient broth. However,when grown in minimal-glucose medium, the frequency of anucleatecells was reduced in all of them and the DNA/protein ratio wasrestored to normal. Especially, the oriC-deleted mutant in whichthe plasmid was integrated near oriC produced almost no anucleatecell. These results indicate that initiation frequency of chromosomereplication from the integrated plasmid origin were reduceddisproportionately to cell mass increase in rich medium, whichin turn disrupted coordination between DNA replication cycleand cell division cycle. The locations of the plasmid originrelative to the natural oriC locus affected the production ofanucleate cell remarkably, suggesting that partition mechanismof chromosome was also impaired by the translocation of itsreplication origin.     

Sequence Analysis of the groESL-cotA Region of the Bacillus subtilis Genome, Containing the Restriction/Modification System Genes

We have determined a 35-kb sequence of the groESL-gutR-cotA(45°–52°) region of the Bacillus subtilis genome.In addition to the groESL, gutRB and cotA genes reported previously,we have newly identified 24 ORFs including gutA and fruC genes,encoding glucitol permease and fructokinase, respectively. Theinherent restriction/modification system genes, hsdMR and hsdMM,were mapped between groESL and gutRB, and we have identifiedtwo open reading frames (ORFs) encoding 5-methylcytosine formingDNA methyl transferase and an operon probably encoding a restrictionenzyme complex. The unusual genome structure of few ORFs andlower GC content around the restriction/modification genes stronglysuggests that the region originated from a bacteriophage integratedduring evolution.     

Effect of N-Methyl-D-Aspartate and Potassium on Striatal Monoamine Metabolism in Immature Rat: An In Vivo Microdialysis Study

Effects of N-methyl-D-aspartate (NMDA) and potassium on 5-day-old rat's brain were examined. We measured extracellular striatal monoamines such as dopamine (DA), 3,4 dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindole-3-acetic acid (5-HIAA) using intracerebral microdialysis. After 3 h stabilization, pups received varying concentrations of NMDA (1–3 mM) and potassium (200–800 mM) by intrastriatal perfusion for 32 minutes. Increasing the concentration of NMDA and potassium induced a dose related DA increase (p < 0.001), whereas DOPAC, HVA, and 5-HIAA decreased significantly. Five days later the same animals were sacrificed and the weight reduction of their cerebral hemispheres was measured. The weight of the drug perfused side was significantly reduced compared with that of the contralateral one. We examined next the relationship between the level of maximum DA and the relative hemisphere weight reduction. The DA peak was highly correlated with the hemisphere weight reduction (r = 0.70, n = 52, p < 0.001 in the NMDA group, r = 0.83, n = 30, p < 0.001 in the potassium group, respectively). These data show that each treatment alter striatal monoamine metabolism in immature rat brain and that the extracellular DA peak is a potential early indicator to estimate brain injury.