The morphology of conidiogenesis and associated changes in microtubules, actin distribution and ultrastructure were studied in the basidiomycetous yeast Fellomyces fuzhouensis by phase-contrast, fluorescence, and electron microscopy. The interphase cell showed a central nucleus with randomly distributed bundles of microtubules and actin, and actin patches in the cortex. The conidiogenous mother cell developed a slender projection, or stalk, that contained cytoplasmic microtubules and actin cables stretched parallel to the longitudinal axis and actin patches accumulated in the tip. The conidium was produced on this stalk. It contained dispersed cytoplasmic microtubules, actin cables, and patches concentrated in the cortex. Before mitosis, the nucleus migrated through the stalk into the conidium and cytoplasmic microtubules were replaced by a spindle. Mitosis started in the conidium, and one daughter nucleus then returned to the mother via an eccentrically elongated spindle. The cytoplasmic microtubules reappeared after mitosis. A strong fluorescence indicating accumulated actin appeared at the base of the conidium, where the cytoplasm cleaved eccentrically. Actin patches then moved from the stalk together with the retracting cytoplasm to the mother and conidium. No septum was detected in the long neck by electron microscopy, only a small amount of fine "wall material" between the conidium and mother cell. Both cells developed a new wall layer, separating them from the empty neck. The mature conidium disconnected from the empty neck at the end-break, which remained on the mother as a tubular outgrowth. Asexual reproduction by conidiogenesis in the long-neck yeast F. fuzhouensis has unique features distinguishing it from known asexual forms of reproduction in the budding and fission yeasts. Fellomyces fuzhouensis develops a unique long and narrow neck during conidiogenesis, through which the nucleus must migrate into the conidium for eccentric mitosis. This is followed by eccentric cytokinesis. We found neither an actin cytokinetic ring nor a septum in the long neck, from which cytoplasm retracted back to mother cell after cytokinesis. Both the conidium and mother were separated from the empty neck by the development of a new lateral wall (initiated as a wall plug). The cytoskeleton is clearly involved in all these processes.

Department of Biology Faculty of Medicine Masaryk University Brno Czech Republic

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J Cell Sci. 2000 Feb;113 ( Pt 4):571-85 PubMed

Microbiology. 1995 Apr;141 ( Pt 4):891-9 PubMed

Fungal Genet Biol. 1999 Nov;28(2):79-93 PubMed

Mol Biol Cell. 2002 Aug;13(8):2747-59 PubMed

Trends Genet. 2003 Jul;19(7):403-8 PubMed

Yeast. 1994 Jul;10(7):851-69 PubMed

Fungal Genet Biol. 2003 Dec;40(3):187-96 PubMed

Microbiology. 1998 Jul;144 ( Pt 7):1783-97 PubMed

J Cell Biol. 1994 Apr;125(2):381-91 PubMed

FEMS Microbiol Lett. 2003 Feb 14;219(1):17-21 PubMed

Microbiology. 1998 Aug;144 ( Pt 8):2331-44 PubMed

Chromosoma. 1995 Nov;104(3):203-14 PubMed

Antonie Van Leeuwenhoek. 1999 May;75(4):361-8 PubMed

Microbiology. 2003 Apr;149(Pt 4):865-76 PubMed

J Cell Sci. 2004 May 1;117(Pt 11):2169-71 PubMed

Fungal Genet Biol. 2001 Nov;34(2):63-82 PubMed

J Cell Sci. 2000 Feb;113 ( Pt 3):365-75 PubMed

Curr Biol. 2004 Sep 21;14(18):R806-18 PubMed

Genes Genet Syst. 1998 Aug;73(4):181-91 PubMed

Int J Syst Evol Microbiol. 2000 May;50 Pt 3:1351-71 PubMed

J Cell Biol. 1974 Jul;62(1):66-76 PubMed

J Struct Biol. 1995 Mar-Apr;114(2):140-52 PubMed

Pediatr Infect Dis J. 2002 Jan;21(1):54-6 PubMed

Fungal Genet Biol. 2002 Nov;37(2):149-70 PubMed

FEMS Yeast Res. 2002 Dec;2(4):495-517 PubMed

AIDS. 2002 May 3;16(7):1031-8 PubMed

Fungal Genet Biol. 1998 Jun-Jul;24(1-2):178-206 PubMed

Eur J Cell Biol. 1986 Aug;41(2):150-6 PubMed

Antonie Van Leeuwenhoek. 1969;35(2):172-7 PubMed

EMBO J. 2003 Feb 3;22(3):438-49 PubMed

Fungal Genet Biol. 2001 Nov;34(2):107-21 PubMed

Genes Genet Syst. 2001 Aug;76(4):257-69 PubMed

Antonie Van Leeuwenhoek. 1966;32(1):99-104 PubMed

J Cell Sci. 2001 Feb;114(Pt 3):609-22 PubMed

Eur J Cell Biol. 2001 Apr;80(4):303-11 PubMed

Arch Mikrobiol. 1967 Jun 6;57(2):135-46 PubMed