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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Panagrolaimus rigidus (Schneider)

Free-living bacteriophagous nematode. The species is primarily amphimictic (Nicholas 1975), but along with the bisexual population some parthenogenetic animals were found. (ref. ID; 1900)

[ref. ID; 1900]

Test system

Anhydrobiotic strategies

Strains

From terrestrial mosses collected in the University campus in Milano (Italy).

Stress

Desiccation.

Test design

Dehydration of the nematodes by placing each individual in the Petri dish (3.5 cm in diameter) between two pieces of wet filter paper (1x1 cm). The dishes were kept in the dark in a closed chamber at 20 degrees C. Desiccated nematodes were rehydrated by adding 0.5 ml liquid meidum (S buffer plus OP50) to each Petri dish.
Age effect: Nematodes aged 4, 8, 12, or 19 days (corresponded to the pre-reproductive (last larval stage, L4), early, middle and late reproductive periods) were kept dry for 6 days. About 100 nematodes for each cohorts. Temperature 20 degrees C.
Time effect: 8-d-old nematodes were dessicated and kept dry for 15, 20, 40, and 60 days.
Each experimental cohort was paired with a control group, but the controls could be run simultaneously for only a part of their lives, because dessication time often exceeded the average life span.

Measurements/observations

All eggs and deaths of parental animals were counted.