Protists acids

The catechol-type ligand appears to be restricted to siderochromes derived from prokaryotic microorganisms. Klebsiella oxytoca, an organism closely related to members of the genus Aerobacter, forms the 2,3-dihy-droxy-N-benzoyl derivates of serine and threonine in three day cultures (72). It is not known if the latter amino acid occurs in trimers but examination of space-filling CPK models does indicate that enterobactin could accomodate a methyl substituent on the carbon of the serine residue. Catechols occur in higher protist organisms but their formation... 

Table 3. Amino acid composition of cytochrome c from some protist organisms...

Table 1 Some naturally occurring simple cyclic dipeptides in the protist and plant kingdoms Diketopiperazine (all amino acids are in the L-configuration) Species...

Rotte C, Stejskal F, Zhu G, Keithly JS, Martin W (2001) Pyruvate NADP+ oxidoreductase from the mitochondrion of Euglena gracilis and from the apicomplexan Cryptosporidium parvum a biochemical relic linking pyruvate metabolism in mitochondriate and amitochondriate protists. Mol Biol Evol 18 710-720 Schnarrenberger C, Martin W (2002) Evolution of the enzymes of the citric acid cycle and the glyoxylate cycle of higher plants. A case study of endosymbiotic gene transfer. Eur J Biochem 269 868-883... 

E. coli detects not only sugars and amino acids but also 02, extremes of temperature, and other environmental factors, using this basic two-component system. Two-component systems have been detected in many other bacteria, including gram-positive and gramnegative eubacteria and archaebacteria, as well as in protists and fungi. Clearly this signaling mechanism developed early in the course of cellular evolution and has been conserved. 

Amino acids have been found within secondary and primary metabolism of all kingdoms. Although quantitative ranking is tricky, at this point bacteria seem to be the most active /l-amino acid chemists , followed by fungi, plants, and animals we exclude protists from this grading list as a consequence of their lower examination status. 

Muller M (1980) The hydrogenosome. Symp Soc Gen Microbiol 30 127-142 Muller M (1985) Search for cell organelles in protozoa. J Protozool 32 559-563 Muller M (1992) Energy metabolism of ancestral eukaryotes a hypothesis based on the biochemistry of amitochondriate parasitic protists. BioSystems 28 33-40 Muller M (2003) Energy metabolism. Part I Anaerobic protozoa. In Marr J, Nilsen T, Komuniecki R (eds) Molecular medical parasitology. Academic, London, pp 125-139 Muller M, Hogg JF, de Duve C (1968) Distribution of tricarboxylic acid cyle enzymes andofgly-oxylate cycle enzymes between mitochondria and peroxisomes of Tetrahymena pyriformis. J Biol Chem 243 5385-5395... 

The second most important mineral phase of the biological pump is biogenic opal, Si02. Opal shells are produced by diatoms, a marine alga, and by radiolarians, a heterotrophic protist. On a large scale, production of Si02 is limited by the availability of dissolved sihca, in the form of silicic acid, H4Si04. 

The steroidal phosphonic acid derivatives 366 and 367 have been synthesised and studied as potential drugs/probes for therapies in the treatment of infections due to various parasitic protists, including the AIDS associated Pneumocystis... 

Biosynthesis of Protist Polyunsaturated Fatty Acids 154 Function of Polyimsaturated Fatty Acids in Protists 156 Polyunsaturated Fatty Acids and Phylogenetic Relationships. 164... 

Pol)umsaturated (or polyenoic) fatty acids are those long-chain fatty acids which include two or more double bonds in the molecule. At least one of these, linoleic acid, 18 2(9,12), has been found in almost every higher protist, plant and animal, so far examined, and in most... 

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