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Laboratory of Cell Cycles

Our group focuses on the regulation of cell cycle in algae characterized by multiple fission. The model organisms employed are Chlamydomonas reinhardtii and Scenedesmus quadricauda (Chlorophyta). Cultivation of synchronized algal cultures and studies of their cell cycles have a 35‑year long history in Třeboň

The recent topics are following:

1. Chloroplast division in cell cycle of green algae
2. Mechanisms of mutual regulatory relationship between the cell size and division
3. Cyclin-dependent kinase activity and CDK complexes in the cell cycle
4. Expression and localization of CDKs on a molecular level
5. We have mastered following methods

We have mastered following methods:

1. Synchronization of algal cultures
   Zachleder V., Šetlík I.(1990): Timing of events in overlapping cell reproductive sequences and their mutual interactions in the alga Scenedesmus quadricauda. Journal of Cell Science 97: 631-638.
2. Characterization of cell cycle progress:
   1. analysis of RNA and DNA content and timing of DNA replication
      Zachleder V.(1986): Optimization of nucleic acids assay in green and blue-green algae: Extraction procedures and the light-activated reaction for DNA. Arch. Hydrobiol. (Suppl. 67) Algolog. Stud. 36: 313-328.
   2. assessment of commitment curves
      Zachleder V., Schläfli O., Boschetti A. (1997): Growth-controlled oscillation in activity of histone H1 kinase during the cell cycle of Chlamydomonas reinhardtii (Chlorophyta). Journal of Phycology 33: 673-681.
      Vítová M., Zachleder V. (2005): Points of commitment to reproductive events as a tool for analysis of the cell cycle in synchronous cultures of algae. Folia Microbiologica: in press.
   3. determination of number of nuclei by means of DNA staining by SYBR Green I or DAPI, nuclear division curves
      Zachleder V.(1986): Nuclei stained by SYBR Green I (left) and by DAPI (right) in Scenedesmus quadricauda
      Vítová M., Hendrychová J., Cepák V., Zachleder V.(2005): Visualization of DNA containing structures in Chlamydomonas reinhardtii and other species of Chlorophyta, Rhodophyta and Cyanophyta using SYBR Green I dye. Folia Microbiologica: in press.
      Zachleder V., Cepák V.(1987): Visualization of DNA containing structures by fluorochrome DAPI in those algal cells which are not freely permeable to the dye. Arch. Hydrobiol. (Suppl. 78) Algolog. Stud. 47: 157-168.
3. Cyclin-dependent kinase activity assay in vitro
   Bišová K., Vítová M., Zachleder V.(2000): The activity of total histone H1 kinases is related to growth and commitment points while the p13(suc1)-bound kinase activity relates to mitoses in the alga Scenedesmus quadricauda. Plant physiology and biochemistry 38: 755-764.
4. Single CDK complex activity assay in-gel
5. Nuclear transformation of Chlamydomonas using glass beads
   Pacanovská M.(2003): Construction of plasmid with E.coli recA⁺ gene to increase frequention of homologous recombination in Chlamydomonas reinhardtii. MSc. thesis. Comenius University, the Faculty of Natural Sciences, Bratislava, Slovak Republic.
   Slaninová M., Fritsche L., Pacanovská M., Fuseková M., Treuner G., Vlček D., Mages W.(2004): New approaches to improve homologous recombination in Chlamydomonas reinhardtii. In book of European Environmental Mutagen Society (Maastricht, the Netherlands).
6. Fluorescence microscopy (Olympus fluorescent microscope BX51 with attached CCD camera, Nomarski (DIC) and phase contrast)
   Vítová M., Hendrychová J., Cepák V., Zachleder V.(2005): Visualization of DNA containing structures in Chlamydomonas reinhardtii and other species of Chlorophyta, Rhodophyta and Cyanophyta using SYBR Green I dye. Folia Microbiologica: in press.
   Hendrychová J., Vítová M., Bišová K., Wiche G., Zachleder V.(2002): Plectin-like proteins are present in cells of Chlamydomonas eugametos (Volvocales). Folia Microbiologica 47: 535-539.