title: Axopodial degradation in the heliozoon Raphidiophrys contractilis: a novel bioassay system for detecting heavy metal toxicity in an aquatic environment.
abstract: We observed the physiological effects of zinc, lead, mercury, copper, cadmium, and arsenic on the axopodia of the centrohelid heliozoon Raphidiophrys contractilis. In the presence of these heavy metal ions, the axopodial length of the heliozoon decreased in a concentration-dependent manner. When the heavy metal ions were examined at the same concentration, mercury produced the strongest effect on axopodia. At a high concentration (> 10-3 M) of any of the heavy metal ions examined, axopodia disappeared and cells became disrupted. Axopodia were also degraded by the addition of solutions with an acidic (< or = 6) or basic (> or = 8) pH. These observations indicate the toxic effects of heavy metal ions and non-neutral pHs on axopodial length, and also signify that R. contractilis can be used as an effective biological tool for the study of metal poisoning in eukaryotic cells.
authors.affiliation: Department of Biology, Faculty of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan.
authors.forename: S M Mostafa Kamal
authors.initials: SM
authors.lastname: Khan
authors.forename: Chisato
authors.initials: C
authors.lastname: Yoshimura
authors.forename: Mikihiko
authors.initials: M
authors.lastname: Arikawa
authors.forename: Gen
authors.initials: G
authors.lastname: Omura
authors.forename: Satoru
authors.initials: S
authors.lastname: Nishiyama
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Suetomo
authors.forename: Soichiro
authors.initials: S
authors.lastname: Kakuta
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Suzaki
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D056890:Eukaryota / Q000187:drug effects*; D019216:Metals, Heavy / Q000032:analysis* / Q000633:toxicity*; D011554:Pseudopodia / Q000187:drug effects*; D018675:Toxicity Tests / Q000379:methods; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity; D014877:Water Pollution, Chemical / Q000009:adverse effects / Q000032:analysis
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D014867:Water