THE ORDER MONOBLEPHARIDALES

OEDOGONIOMYCES IN THE CLASSROOM


Cultures of isolate CR90 of Oedogoniomyces can be obtained from the University of California at Berkeley Microgarden. The unbranched, somewhat arched, filamentous thalli are attached to the substrate at the basal, or proximal, end by a non-cellular, disk-like holdfast or appressoria.  Oedogoniomyces is not known to reproduce sexually. Sporangia mature in basipetal succession starting with the conical distal segment and followed by several H-shaped segments, with each thallus segment producing zoospores only once.  The posteriorly  uniflagellate zoospores escape through a transverse cleavage near the upper end of each segment.  Note the large size of Oedogoniomyces compared with the similar but much smaller growth of Harpochytrium.

CAUTION - Use sterile technique at all times. Sterilize all glassware and media by autoclaving before use. 

LONG TERM MAINTENANCE – If desired, isolate CR90 of Oedogoniomyces is easily maintained in flasks containing 50 ml of T/2 stored at room temperature (22°C) and transferred every 3 months.

PREPARATION TIME -   Begin “Day 0” 14 days before expected use.

DAY 0 - Shake stock flask, grown for at least 3 weeks, to loosen thalli and start new stock flask by transferring, with a sterile pipette, 1 or 2 mL from present stock to a new flask containing 50 mL of T/2.  With sterile pipette, transfer 1 or more mL of the remaining material in the present stock flask to each sterilized Petri plate containing cover slips needed for class.  Add enough sterile T/2 from stock bottle to cover the slips in each Petri plate.  You will probably need to rearrange the cover slips with a sterile needle or other tool to spread them evenly over the bottom of the Petri plate.  Grow for 2 weeks in the light at room temperature (~22° C).

IN CLASS - DAY 14 - Use sterile forceps to remove an individual cover slip, wipe the under side of the cover slip dry, and invert the cover slip over a small drop of water on a clean microscope slide for observation. 

SCHEDULE ADJUSTMENT - If careful sterile technique is observed and the plates remain uncontaminated, observation should be possible for 2 or 3 additional days.

RECIPE - T/2 broth for flasks, stock bottle, and Petri dishes with cover slips.

MATERIALS NEEDED - In addition to 250 ml Erlenmyer flasks containing 50 ml of T/2 (for long term maintenance) you will need for each 5 students:  1 glass Petri dish containing 5 glass cover slips, thickness 1 ½ and 500 ml bottle for T/2 supply.

REFERENCES -

Emerson, Ralph and Howard C. Whisler.  1968. Cultural studies of Oedogoniomyces and Harpochytrium, and a proposal to place them in a new order of aquatic phycomycetes.  Archiv für Mikrobiologie  61: 195 - 211.

Karling, John S.1977. Chytridiomycetarum Iconographia. Lubrecht & Cramer. Monticello,N.Y.

Kobayashi,  Yoshio and Mariko Ôkubo. 1954. On  new genus Oedogoniomyces of the Blastocladiaceae . Bulletin of the National Science Museum (Tokyo), N.S. Vol.1,No. 1(No.34) March, 1954.  


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