Cyclopyxis kahli

[ref. ID; 2848]

Test system

Effects of light, temperature, fertilizers and pesticides on shell size

Strains

Clone G20. This species was isolated in May 1990 from the humus layer of a spruce forest (site U1, see Funke 1991, Wanner 1991).

Toxicants/concentrations

Ripcord 10, SHELL (Ripcord 10 is an emulsion of 100 g l-1 cypermethrin, a synthetic pyrethroid): 0.01 ul solution (1 ug a.i.) or 0.05 ul solution (5 ug a.i.) per petri dish. Spruzit, Neudorff (Spruzit is an emulsion of 4% pyrethrine and 16% piperonyl butoxide): 0.05 ul or 0.2 ul emulsion per petri dish.

Environmental stress

Light: Cultures were illuminated by a 60-W bulb, distance 60 cm.
Temperature: 17+/-0.5 degrees C or 21+/-0.5 degrees C.
Fertilizer: 0.25 mg % Ca(NO3)2 NH4NO3 per petri dish.
Lime: 1 mg 95% CaCO3 per petri dish.

Test design

It has an agglutinate shell built of exogenous material (xenosomes), mainly sand grains, therefore the experimental had to provide for the sand grains occuring in the original biotop. Clones were cultivated in petri dishs (diameter 35 mm) containing Agar (1%) covered with culture medium (2 ml "Volvic, commercial mineral water + KH2PO4, 50 mg l-1). All cultures were provided with shell building material surplus. Subcultures were established by introducing 5 individuals of the clone to a new petri dish. Therefore the initial cultures for the experiments consisted of 5 individuals. An inoculum of 5 Cyclopyxis kahli produces under the given circumstances between 1000 and 2000 individuals, therefore 8 to 9 cell division have happened.

Measurements/observations

Cell number.

Evaluations

The lag time, the generation time, and the time for about 4 cell divisions - about 100 individuals per culture. ("h100").

[ref. ID; 2851]