AIMS

The origin of the most conspicuous cell organelle of photoautotrophic eukaryotes, the plastid, is not really understood. Especially for the evolution of phyletic primary plastids endogenous or exogenous mechanisms have been contradictorily discussed. The exogenous evolution of plastids, widely accepted as intertaxonic combination, is described formally by the Serial Endosymbiosis Theory (SET) and needs over all two mechanisms which have not been prooven satisfactorily: gene transfer and after or during this process the development and adaptation of the posttranslational protein-import machinery for the new "metahost" nucleus-encoded proteins of the evolving cell organelle (meta-endocytobiont -> exogenosome). Furthermore, for reciprocal control of both compartments, new signal transduction ways have to be evolved between cytoplasmic space and the new organellic space. Discovery and molecular biological description of these evolutionary new cellular properties including aspects of phylogeny of these biological systems are the scope of our research.

RESEARCH OBJECTS

metacyanomes: Cyanophora paradoxa (Glaucocystophyta), cyanobacteria

REFERENCES (1992-1996) ("A" before citation = abstract)

Gebhart, U.B., Maier, T.L., Stevanovic, S., Bayer, M.G., and Schenk, H.E.A., 1992. Ferredoxin-NADP oxidoreductase of Cyanophora paradoxa Purification, partial characteriza-tion, and N-terminal amino acid sequence. Protein Expression and Purific. 3:228-235.

Schenk, H.E.A., Bayer, M.G., Maier, T.L., Lüttke, A., Gebhart, U.B., and Stevanovic, S., 1992. Ferredoxin-NADP+-Oxidoreductase of C. paradoxa nucleus encoded, but cyanobacterial. Gene transfer from symbiont to host, an evolutionary mechanism originating new species. Z. Naturforsch. 47c:387-393.

Schenk, H.E.A., 1992a. Cyanobacterial Symbioses. In: The Prokaryotes. A Handbook of ecophysiology, isolation, identification, application. (Ballows, A. et al., eds.), Vol. 4, pp. 3819-3854. Springer, New York.

Schenk, H.E.A., 1992b. Cyanophora paradoxa , identification and sequencing of nucleus-encoded cyanellar proteins. A proof for gene transfer. Endocytobiosis & Cell Res. 8:215-222.

A: Schenk, H.E.A., 1992c. From cyanelle to cyanoplast: A first direct indication of gene transfer between symbiont and host. Abstracts, ENDOCYTOBIOLOGY V, Kyoto, p. 50.

A: Schenk, H.E.A., 1992d. Some thoughts towards a discussion of terms and definitions in endocytobiology. Abstracts, ENDOCYTOBIOLOGY V, Kyoto, p. 77.

Jakowitsch, J., Bayer, M.G., Maier, T.L., Gebhart, U.B., Lüttke, A., Brandtner, M., Hamilton. B., Neumann-Spallart, C., Michalowski, C.B., Bohnert, H.J., Schenk, H.E.A., and Löffelhardt, W., 1993. Sequence analysis of pre-ferredoxin- NADP-reductase cDNA from Cyanophora paradoxa specifying a precursor polypeptide. Plant Mol. Biol. 21:1023-1033.

Schenk, H.E.A. 1993. Some thoughts towards a discussion of terms and definitions in endocytobiology. In. Endocytobiology V (S. Sato, M. Ishida, H. Ishikawa, eds.), pp. 547-556. ATTEMPTO-Verlag, Tübingen.

Schenk, H.E.A., 1993. Ist Endocytobiologie eine selbständige Wissenschaft? ISE News Let-ters, ISEG Brief (1993), p.7-12.

Schenk, H.E.A., Jakowitsch, J., Bayer, M.G., Maier, T.L., Lüttke, A., Bohnert, H.J., Löffelhardt, W. 1993. From cyanelle to cyanoplast: The amino acid sequence of pre-FNR, a first direct indication of gene transfer from symbiont to host. In. Endocytobiology V (S. Sato, M. Ishida, H. Ishikawa, eds.), pp. 329-334. ATTEMPTO-Verlag, Tübingen.

A: Schenk, H.E.A., 1993. From cyanelle to cyanoplast: Intertaxonic combination and evolutive consequences. Abstracts, EVOLUTION 93, Montpellier 1993, p. 402.

Gross, W., Bayer, M.G., Schnarrenberger, C., Gebhart, U.B., Maier, T.L., and Schenk, H.E.A. (1994). Two distinct aldolases of Class II type in the cyanoplasts and in the cytosol of the alga Cyanophora paradoxa Plant Physiol. 105:1393-1398.

Lüttke, A., Maier, T.L., and Schenk, H.E.A. (1994). Codon usage adaptation in the ferre-doxin-NADP+-oxidoreductase of Cyanophora paradoxa upon translocation from cyano-plast to nucleus. Gene 146:123-127.

Schenk, H.E.A. (1994a). Cyanophora paradoxa : Anagenetic model or missing link of plastid evolution? Endocytobiosis & Cell Res. 10: 87-106.

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A: Schenk, H.E.A., and Hauler, O. (1994): The Phycobiliproteins of Cyanophora paradoxa are storage proteins for carbon, nitrogen and sulfur. Endocytobiosis & Cell Res. 10: 256.

Schenk, H.E.A. (1995). Endosymbiosetheorie, Plastidenevolution und ein Weg zur Entstehung neuer Arten. In: J. Mey, R. Schmidt und S. Zibulla (eds.) Streitfall Evolution. S. Hirzel - WVG Stuttgart, pp.105-130.

Schenk, H.E.A. (ed.): Endocytobiology VI, Intertaxonic combination and symbiotic adaptation. Program and Abstracts Volume of ãthe Sixth International Colloquium on Endocytobiology and Symbiosis" of the International Society of Endocytobiology in Zusammenarbeit mit der Universität Tübingen. Tübingen (1995).

A: Fester, T., Völkle, E., and Schenk, H.E.A. (1995). Cyanophora paradoxa : Purification and partial characterization of the Glucose-6-phosphate Dehydrogenase from cyanoplasts. In: Endocytobiology VI, Program and Abstracts, Tübingen, p. 9.

A: Müller, N.E., Hauler, O., and Schenk, H.E.A. (1995). The Phycobiliproteins in the cyanoplasts of Cyanophora paradoxa are storage proteins of the whole cell for carbon, nitrogen and sulfur. In: Endocytobiology VI, Program and Abstracts, Tübingen, p. 43.

Jakowitsch J., Neumann-Spallart C., Ma Y., Steiner J., Schenk H.E.A., Bohnert H.J., Löffelhardt W. (1996): In vitro import of pre-ferredoxin-NADP+-oxidoreductase from Cyanophora paradoxa into cyanelles and into chloroplasts. FEBS Letters 381: 153-155.

Fester, T., Völkle, E., and Schenk, H.E.A. (1996). Purification and partial characterization of the cyanoplast Glucose-6-phosphate Dehydrogenase in Cyanophora paradoxa . Endocytobiosis & Cell Res. 11: 159-176.