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Berlin Brandenburg

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  • 1
    Language: English
    In: Environmental Toxicology and Chemistry, 2001, Vol.20(9), p.2088
    Description: We studied the chronic effects of 4-nonylphenol (4-NP) on reproductive status of medaka (Oryzias latipes) over two generations of continuous exposure. The exposure study of the parental (F0) medaka was begun on embryos within 24 h post-fertilization and continued with monitoring through embryological development, hatching, posthatch survival, growth, sexual differentiation, and reproduction under flow-through exposures to mean measured 4-NP concentrations of 4.2, 8.2, 17.7, 51.5, and 183 µg/litre for up to 104 d. Eggs spawned from the F0 fish at 102 and 103 d posthatch were also examined for hatchability, survival after hatching, growth, and sexual differentiation until 60 d posthatch. The 183-µg/litre treatment significantly reduced the embryo survival and swim-up success of the F0 fish. The cumulative mortality after swim-up of the F0 fish exposed to 17.7 and 51.5 µg/litre were significantly higher than the control mortality. No concentration-related effect of 4-NP was observed on the growth of surviving F0 fish at 60 d posthatch. However, the sex ratio estimated from the appearance of their secondary sex characteristics was skewed toward female in the 51.5-µg/litre treatment. Additionally, gonadal histology showed that 20% of the fish in the 17.7-µg/litre treatment and 40% in the 51.5-µg/litre treatment had testis-ova, indicating that 4-NP affects the gonadal development and survival of medaka at similar concentrations in juveniles. The sex ratio of the F0 fish in the 51.5-µg/litre treatment was completely skewed toward female; subsequently, the effects on fecundity and fertility in this generation were monitored at mean measured concentrations of 4.2, 8.2, and 17.7 µg/litre from 71 to 103 d posthatch. Fecundity was unaffected by any of the treatments examined. The mean fertility in the 17.7-µg/litre treatment was reduced to 76% of that in the controls, although no statistically significant differences were determined. Overall, these results indicate that the lowest-observed-effect concentration (LOEC) and no-observed-effect concentration (NOEC) of 4-NP through the life cycle of the F0 medaka were 17.7 and 8.2 µg/litre, respectively. In the F1 medaka, no significant effects were observed on hatching success, posthatch mortality, or growth, but sexual differentiation at 60 d posthatch was affected. Induction of testis-ova in the gonads of the F1 fish was observed in both the 8.2- and the 17.7-µg/litre concentrations. The results indicate that 4-NP can have significant effects on reproductive potential of medaka at concentrations as low as 17.7 µg/litre.
    Keywords: Aquatic Animals ; Aquatic Organisms ; Embryonic Development ; Embryos ; Growth ; Mortality ; Nontarget Effects ; Ovaries ; Reproduction ; Sex Differentiation ; Survival ; Testes ; Toxic Substances ; Toxicity ; Toxicology ; Aquatic Species ; Death Rate ; Embryo Development ; Embryo Growth ; Nonylphenols ; Poisons ; Testicles ; Oryzias Latipes ; Oryzias ; Adrianichthyidae ; Beloniformes ; Osteichthyes ; Fishes ; Vertebrates ; Chordata ; Animals ; Eukaryotes;
    ISSN: 0730-7268
    E-ISSN: 1552-8618
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  • 2
    Language: English
    In: Cellular Physiology and Biochemistry, August 2011, Vol.28(2), pp.185-198
    Description: Extracellular matrix proteins, adhesion molecules, and cytoskeletal proteins form a dynamic network interacting with signalling molecules as an adaptive response to altered gravity. An important issue is the exact differentiation between real microgravity responses of the cells or cellular reactions to hypergravity and/or vibrations. To determine the effects of real microgravity on human cells, we used four DLR parabolic flight campaigns and focused on the effects of short-term microgravity (22 s), hypergravity (1.8 g), and vibrations on ML-1 thyroid cancer cells. No signs of apoptosis or necrosis were detectable. Gene array analysis revealed 2430 significantly changed transcripts. After 22 s microgravity, the F-actin and cytokeratin cytoskeleton was altered, and ACTB and KRT80 mRNAs were significantly upregulated after the first and thirty-first parabolas. The COL4A5 mRNA was downregulated under microgravity, whereas OPN and FN were significantly upregulated. Hypergravity and vibrations did not change ACTB, KRT-80 or COL4A5 mRNA. MTSS1 and LIMA1 mRNAs were downregulated/slightly upregulated under microgravity, upregulated in hypergravity and unchanged by vibrations. These data indicate that the graviresponse of ML-1 cells occurred very early, within the first few seconds. Downregulated MTSS1 and upregulated LIMA1 may be an adaptive mechanism of human cells for stabilizing the cytoskeleton under microgravity conditions.
    Keywords: Original Paper ; Thyroid Cancer ; Extracellular Matrix ; Apoptosis ; Cytoskeleton ; Weightlessness ; Microgravity ; Hypergravity ; Vibration ; Biology ; Chemistry
    ISSN: 1015-8987
    E-ISSN: 1421-9778
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