DNA damage and p53 in RAW264.7 cells induced by the spores of co-cultivated Streptomyces californicus and Stachybotrys chartarum.
Our recent studies have revealed that the co-cultivation of environmental microbes, Streptomyces californicus and Stachybotrys chartarum, potentiates the immunotoxic properties of the spores. In the present study, the spore-induced genotoxic potential of these microbes was investigated. Dose related differences in genotoxic and cytotoxic effects and in p53 level in mouse RAW264.7 macrophages were studied after 24h exposure to the spores of separately cultivated Streptomyces californicus or Stachybotrys chartarum alone, a simple spore-mixture of these microbes as well as to the spores of co-cultivated microbes. The genotoxic effect of the exposures was determined by the Comet assay and p53 level was analyzed by immunoblotting. Cytotoxicity was assessed by using flow cytometric analysis and also by the MTT test. The results revealed that the spores of co-cultivated microbes evoked DNA damage, p53 accumulation and cytotoxicity at a lower dose than the other exposures, and at the highest dose there was a 2.5-fold increase in DNA damage compared to control. In addition, the spores of Streptomyces californicus alone induced a 1.5-fold increase in DNA damage compared to control, dose dependent p53 accumulation and also extensive cytotoxicity. In contrast, the mixture of separately cultivated spores or the spores of Stachybotrys chartarum alone did not induce DNA damage with any tested dose although they triggered significant cytotoxicity and a slightly increased p53 level. Our results suggest that the detected genotoxic responses are the result of DNA damage in RAW264.7 cells by some genotoxically active metabolite(s) and the production of this compound was stimulated in Streptomyces californicus when it was co-cultivated with Stachybotrys chartarum.
Penttinen
Piia
P
National Public Health Institute, Department of Environmental Health, PO Box 95, FI-70701 Kuopio, Finland. Piia.Penttinen@ktl.fi
Tampio
Marjo
M
Mäki-Paakkanen
Jorma
J
Vähäkangas
Kirsi
K
Pelkonen
Jukka
J
Hirvonen
Maija-Riitta
MR
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001427:Bacterial Toxins / Q000378:metabolism / Q000633:toxicity*; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D008264:Macrophages / Q000187:drug effects* / Q000473:pathology; D051379:Mice; D009153:Mutagens / Q000378:metabolism / Q000633:toxicity*; D009183:Mycotoxins / Q000378:metabolism / Q000633:toxicity*; D013171:Spores, Bacterial / Q000378:metabolism; D013172:Spores, Fungal / Q000378:metabolism; D013191:Stachybotrys / Q000378:metabolism* / Q000472:pathogenicity; D013302:Streptomyces / Q000378:metabolism* / Q000472:pathogenicity; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D015854:Up-Regulation
D001427:Bacterial Toxins; D009153:Mutagens; D009183:Mycotoxins; D016159:Tumor Suppressor Protein p53