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S Kobe

Publications and source records attributed to S Kobe.

4 recordsLinked to original sources
PubMed2001

Time decay of the remanent magnetization in the +/-J spin glass model at T=0.

Using the zero-temperature Metropolis dynamics, the time decay of the remanent magnetization in the +/-J Edward-Anderson spin glass model with a uniform random distribution of ferromagnetic and antiferromagnetic interactions has been investigated. Starting from the saturation, the magnetization per spin m reveals a slow decrease with time, which can be approximated by a power law: m(t)=m(infinity)+(t/a(0))(a(1)), a(1)<0. Moreover, its relaxation does not lead it into one of the ground states, and therefore the system is trapped in metastable isoenergetic microstates remaining magnetized. Such behavior is discussed in terms of a random walk that the system performs on its available configuration space.

Journal Article↗
PubMed1999

Biosynthesis of glycosylphosphatidylinositols of Plasmodium falciparum in a cell-free incubation system: inositol acylation is needed for mannosylation of glycosylphosphatidylinositols.

The structures of glycosylphosphatidylinositols (GPIs) in Plasmodium have been described [Gerold, Schuppert and Schwarz (1994) J. Biol. Chem. 269, 2597-2606]. A detailed understanding of GPI synthesis in Plasmodium is a prerequisite for identifying differences present in biosynthetic pathways of parasites and host cells. A comparison of the biosynthetic pathway of GPIs has revealed differences between mammalian cells and parasitic protozoans. A cell-free incubation system prepared from asexual erythrocytic stages of Plasmodium falciparum, the causative agent of malaria in humans, is capable of synthesizing the same spectrum of GPIs as that found in metabolically labelled parasites. The formation of mannosylated GPIs in the cell-free system is shown to be inhibited by GTP and, unexpectedly, micromolar concentrations of GDP-Man. Lower concentrations of GDP-Man affect the spectrum of GPIs synthesized. The inositol ring of GPIs of P. falciparum is modified by an acyl group. The preferred donor of this fatty acid at the inositol ring is myristoyl-CoA. Inositol acylation has to precede the mannosylation of GPIs because, in the absence of acyl-CoA or CoA, mannosylated GPIs were not detected. Inositol myristoylation is a unique feature of plasmodial GPIs and thus might provide a potential target for drug therapy.

Acetylglucosamine↗