Riboflavin mobilization from eleocyte stores in the earthworm Dendrodrilus rubidus inhabiting aerially-contaminated Ni smelter soil.
A 6-week reciprocal transfer laboratory exposure experiment was conducted with two populations of the epigeic earthworm Dendrodrilus rubidus; one population inhabited a site approx. 200 m downwind of an active Ni smelter co-contaminated with Ni and Cu (3648 and 977 microg g(-1)d.w., respectively), the other inhabited uncontaminated soil. Worms transferred from unpolluted to Ni/Cu-polluted soil lost body mass (62%); they also had reduced (70%) total coelomocyte number, including autofluorescent eleocytes, and had significantly decreased (92%) riboflavin-derived fluorescence emission measured at 525 nm. Coelomocyte counts were low, and 525 nm emission was negligible in worms maintained on their native Ni/Cu soil. Earthworms and their coelomocytes were unaffected when transferred from Ni/Cu-polluted soil to unpolluted soil. In conclusion, exposing worms to stress-inducing factors, including metal pollution, alters the riboflavin status within the immune-competent cells of D. rubidus, but it requires further in vivo studies to establish whether the reduction in the fluorescence signal is predominantly due to depletion of riboflavin-containing eleocytes, or to riboflavin quenching, or to enzymatic conversion (and thus depletion) of stored riboflavin into its functional immune-potentiating flavin derivatives, FMN and FAD. The flavin budget of D. rubidus coelomocytes recovered by a reproducible extrusion procedure is a potentially useful biomarker for assessing sublethal stress in this early colonizer of disturbed soils.
Plytycz
Barbara
B
Institute of Zoology, Jagiellonian University, Krakow, Poland. barbara.plytycz@uj.edu.pl
Kielbasa
Edyta
E
Grebosz
Anna
A
Duchnowski
Michal
M
Morgan
A John
AJ
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D004064:Digestive System / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D009532:Nickel / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D009835:Oligochaeta / Q000187:drug effects / Q000378:metabolism*; D012256:Riboflavin / Q000378:metabolism*; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D013050:Spectrometry, Fluorescence
D015415:Biomarkers; D012989:Soil Pollutants; D009532:Nickel; D012256:Riboflavin