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The putrescine-biosynthesis pathway in Tetrahymena thermophila was delineated by studying crude extracts prepared from exponentially growing cultures. A pyridoxal phosphate-stimulated ornithine decarboxylase activity competitively inhibited by putrescine was detected. CO2 was also liberated from L-arginine, but analyses by t.l.c. and enzyme studies(More)
Fifteen amicronucleate cell lines and 22 cell lines with defective micronuclei were obtained following selective laser microbeam irradiation of the micronucleus. The amicronucleate cell lines showed reduced growth rate and formed abnormal oral apparatuses in asexual reproduction, and failed to produce any oral apparatus in autogamy, in agreement with(More)
In ciliates, the major morphogenetic events take place in the cortex, a complex of membranes and closely associated filamentous networks. To analyze the problems of assembly and morphogenesis at the molecular level in Paramecium, we have developed a method of purification of cortex fragments which retain their in situ organization and display a highly(More)
We report the clinical, biochemical, neuroradiological, and neurophysiological findings of a 4-year-old Chinese girl with infantile isolated sulphite oxidase deficiency. This is the first reported case in our locality. She presented at the age of 5 months with refractory seizures and developmental regression, and progressed rapidly to profound psychomotor(More)
  • S F Ng
  • 1977
The contractile vacuole pores (CVPs) in Tetrahymena pyriformis are usually found to the left of ciliary meridians (CVP meridians). When the CVP meridians are experimentally rotated 180 degrees ('inverted'), the CVPs are now found to the right of the rotated CVP meridians. In other words, the CVP is almost invariably found on the same side with respect to(More)
  • S F Ng
  • 1978
A temperature-sensitive mutant homozygous for the recessive gene molb in Tetrahymena thermophila offers opportunity for studying the direction of microtubule assembly in vivo. At 39 degrees C the mutant fails to divide properly; the 2 daughter animals remain attached and bend over each other. As revealed by protargol staining, the bending results in acute(More)
The present study of the cytoskeleton of Paramecium employed a number of heterologous monoclonal antisera raised against intermediate filament proteins of higher organisms, and also an antiserum against a 49 K protein from Tetrahymena. Anti-49 K, and also monoclonal anti-bovine cytokeratin K 8.13 which has a broad cross-reaction spectrum for epithelial(More)
Removal of the micronuclei from Paramecium generated amicronucleate cell lines which produced oral apparatuses of much reduced length and abnormal oral membranellar pattern during an initial depression period. They subsequently recovered, but only partially. Reimplantation of the amicronucleates with micronuclei generally allowed a greater oral length to be(More)
The present paper reports on the experimental analysis of a novel regulatory function of the micronucleus of Paramecium tetraurelia. Previous studies have made clear that amicronucleate cell lines shortly after their generation generally suffer depression, in exhibiting low viability, slow growth and abnormal oral development in binary fission, but they(More)