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Archives of Microbiology

, Volume 183, Issue 4, pp 292–300 | Cite as

Cytoplasmic contractions in growing fungal hyphae and their morphogenetic consequences

  • Cristina G. Reynaga-Peña
  • Salomón Bartnicki-GarcíaEmail author
Original Paper

Abstract

Video-enhanced light microscopy of the apical and subapical regions of growing hyphae of several fungal species revealed the existence of momentary synchronized motions of subcellular organelles. First discovered in a temperature-sensitive morphological mutant (ramosa-1) of Aspergillus niger, these seemingly spontaneous cytoplasmic contractions were also detected in wild-type hyphae of A. niger, Neurospora crassa, and Trichoderma atroviride. Cytoplasmic contractions in all fungi lasted about 1 s. Although the cytoplasm recovered its motility and appearance, the contraction usually led to drastic changes in Spitzenkörper (apical body) behavior and hyphal morphology, often both. Within 10 s after the contraction, the Spitzenkörper commonly became dislodged from its polar position; sometimes it disassembled into phase-dark and phase-light components; more commonly, it disappeared completely. Whether partial or complete, the dislocation of the Spitzenkörper was always accompanied by a sharp reduction or cessation of growth, and was usually followed by marked morphological changes that included bulbous hyphal tips, bulges in the hyphal profile, and formation of subapical and apical branches. The cytoplasmic contractions are vivid evidence that the most conspicuous cell organelles (membrane-bound) in living hyphae are interconnected via a contractile cytoskeletal network.

Keywords

Cytoplasmic contractions Fungal growth Spitzenkörper Organelle movement Ramosa-1 Aspergillus niger Neurospora crassa Trichoderma atroviride 

Notes

Acknowledgements

We thank Robert W. Roberson and Meritxell Riquelme for valuable advice and Ricardo Mendoza for his help with digitalization of video sequences. The experimental portion of this work was supported in part by grants from the National Institutes of Health (GM-48257), the National Science Foundation (IBN-9204541), a special grant from Consejo Nacional de Ciencia y Tecnología, Mexico (DG/2003-1158), and fellowships from SNI (Sistema Nacional de Investigadores, México).

Supplementary material

ESM1 Supplementary material related to Fig. 1. Videotape of a growing A. niger hyphal tip. It is shown a 5 s sequence which contains the cytoplasmic contraction analyzed and described in Fig. 1. The image in Fig. 1B corresponds to video screen time of 00:19:33

(MPEG 740 KB)

ESM2 Supplementary material related to Fig. 4. Videotape of a growing N. crassa hyphal tip. A 4 s sequence containing the cytoplasmic contraction that triggers the events shown in Fig. 4. Video screen time 00:58:47 7 corresponds to time 0 s in Fig. 4A

(AVI 1.4 MB)

ESM3 Supplementary material related to Fig. 6. Videotape of a T. atroviride hyphal tip. It is shown a 9 s sequence where three cytoplasmic contractions occur at the hyphal apex analyzed in Fig. 6. Video screen time of 00:12:55 5 corresponds to time 0 s in Fig. 6B

(AVI 3.1 MB)

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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Cristina G. Reynaga-Peña
    • 1
  • Salomón Bartnicki-García
    • 2
    • 3
    Email author
  1. 1.Centro de Investigación y de Estudios Avanzados del I.P.N. Unidad IrapuatoIrapuatoMéxico
  2. 2.Department of Plant PathologyUniversity of CaliforniaRiversideUSA
  3. 3.Centro de Investigación Científica y de Educación Superior de EnsenadaEnsenadaMéxico

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