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1.
Mar Pollut Bull ; 203: 116446, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38703627

ABSTRACT

Perfluorooctanesulfonic acid (PFOS) is detected in estuarine environments, where salinity levels fluctuate regularly. We investigated the effects of salinity on the toxicity of PFOS in embryos and larvae of Cyprinodon variegatus. We crossed six PFOS treatments (0, 1-10,000 µg/L) with two salinities (10, 30 ppt). Larvae exposed to the highest concentration of PFOS under high salinity accumulated over twice the amount of PFOS compared to larvae maintained under low salinity. Embryonic survival was unaffected by PFOS, salinity, or their interaction. PFOS delayed time to hatch and increased salinity reduced time to hatch regardless of PFOS treatment; however, no salinity by PFOS interactions were observed. Conversely, PFOS and salinity interacted in the larval stage, with decreased survival at 30 ppt salinity. This is one of the first studies evaluating interactive effects of PFOS and high salinity and highlights the importance of assessing PFAS toxicity across life stages.


Subject(s)
Alkanesulfonic Acids , Fluorocarbons , Larva , Salinity , Water Pollutants, Chemical , Animals , Fluorocarbons/toxicity , Alkanesulfonic Acids/toxicity , Water Pollutants, Chemical/toxicity , Larva/drug effects , Estuaries , Killifishes/physiology , Embryo, Nonmammalian/drug effects
2.
Environ Toxicol Chem ; 43(7): 1537-1546, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38629586

ABSTRACT

Per- and polyfluoroalkyl substances (PFAS) are environmental contaminants of growing concern due to their potential negative effects on wildlife and human health. Per- and polyfluoroalkyl substances have been shown to alter immune function in various taxa, which could influence the outcomes of host-parasite interactions. To date, studies have focused on the effects of PFAS on host susceptibility to parasites, but no studies have addressed the effects of PFAS on parasites. To address this knowledge gap, we independently manipulated exposure of larval northern leopard frogs (Rana pipiens) and parasites (flatworms) via their snail intermediate host to environmentally relevant PFAS concentrations and then conducted trials to assess host susceptibility to infection, parasite infectivity, and parasite longevity after emergence from the host. We found that PFAS exposure to only the host led to no significant change in parasite load, whereas exposure of parasites to a 10-µg/L mixture of PFAS led to a significant reduction in parasite load in hosts that were not exposed to PFAS. We found that when both host and parasite were exposed to PFAS there was no difference in parasite load. In addition, we found significant differences in parasite longevity post emergence following exposure to PFAS. Although some PFAS-exposed parasites had greater longevity, this did not necessarily translate into increased infection success, possibly because of impaired movement of the parasite. Our results indicate that exposure to PFAS can potentially impact host-parasite interactions. Environ Toxicol Chem 2024;43:1537-1546. © 2024 SETAC.


Subject(s)
Host-Parasite Interactions , Rana pipiens , Animals , Host-Parasite Interactions/drug effects , Rana pipiens/parasitology , Echinostomatidae/drug effects , Snails/parasitology , Snails/drug effects , Fluorocarbons/toxicity , Larva/drug effects , Water Pollutants, Chemical/toxicity , Environmental Pollutants/toxicity
3.
Environ Sci Technol ; 57(48): 19274-19284, 2023 Dec 05.
Article in English | MEDLINE | ID: mdl-37943624

ABSTRACT

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals with several applications. Multiple adverse health effects are reported for longer carbon chain (≤C8) PFAS. Shorter carbon chain PFAS, [e.g., hexafluoropropylene oxide dimer acid (HFPO-DA; GenX) and perfluorobutanesulfonic acid (PFBS)] were introduced as alternatives. Past studies indicate that longer-chain PFAS are neurotoxic targeting the dopamine pathway, but it is not known if shorter-chain PFAS act similarly. This study aimed to evaluate developmental neurotoxicity and tissue uptake of GenX and PFBS using the zebrafish (Danio rerio). First, acute toxicity was assessed by measuring LC50 at 120 h postfertilization (hpf). Body burden was determined after embryonic exposure (1-72 hpf) to sublethal concentrations of GenX or PFBS by LC-ESI-MS/MS. Locomotor activity using a visual motor response assay at 120 hpf and dopamine levels at 72 hpf was assessed after embryonic exposure. PFBS was more acutely toxic and bioaccumulative than GenX. GenX and PFBS caused hyperactivity at 120 hpf, but stronger behavioral alterations were observed for PFBS. An increase in whole organism dopamine occurred at 40 ppb of GenX, while a decrease was observed at 400 ppb of PFBS. Differences detected in dopamine for these two PFAS indicate differential mechanisms of developmental neurotoxicity.


Subject(s)
Alkanesulfonic Acids , Fluorocarbons , Animals , Zebrafish , Tandem Mass Spectrometry , Dopamine , Fluorocarbons/toxicity , Carbon , Alkanesulfonic Acids/metabolism , Alkanesulfonic Acids/toxicity
4.
Environ Sci Technol ; 56(10): 6078-6090, 2022 05 17.
Article in English | MEDLINE | ID: mdl-35486899

ABSTRACT

Researchers have developed numerous per- and polyfluoroalkyl substances (PFAS)-free aqueous film-forming foam (AFFF) formulations to replace PFAS-containing AFFF used for fire suppression. As part of the Department of Defense's Strategic Environmental Research and Development Program (SERDP), we examined the direct lethal effects of seven PFAS-free AFFF and a PFAS-containing AFFF on 14 aquatic species using a series of lethal concentration (LC50) tests. We assessed the LC10, LC50, and LC90 values using log-logistic and logit analyses. Across all aquatic species tested, we discovered that exposure to at least one PFAS-free AFFF was more or as toxic as exposure to the PFAS-containing AFFF. For most cases, National Foam Avio F3 Green KHC 3% and Buckeye Platinum Plus C6MILSPEC 3% were the most and least toxic formulations, respectively. Moreover, we found consistency among results from multiple experiments using the same minnow species (Pimephales promelas) and among closely related taxa (e.g., daphnids, amphibians). Lastly, the LC50 values for AFFF formulations trended lower for tested marine species as compared to those of freshwater species. These results dramatically increase the current knowledge on the potentially toxic effects of AFFF but also highlight the need for additional research and the development of new PFAS-free AFFF that are more "ecologically friendly" than those containing persistent PFAS.


Subject(s)
Fluorocarbons , Water Pollutants, Chemical , Aerosols , Fluorocarbons/analysis , Water , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/toxicity
5.
J Comp Neurol ; 482(4): 372-85, 2005 Feb 21.
Article in English | MEDLINE | ID: mdl-15669053

ABSTRACT

To gain insight into regulatory mechanisms of tissue-specific Corazonin (Crz) gene expression and its functions in Drosophila, we cloned the Crz genes from four Drosophila species (D. melanogaster, D. simulans, D. erecta, and D. virilis) and performed comparative analyses of Crz gene sequences and expression patterns using in situ hybridization and immunohistochemistry. Although Crz gene sequences showed a great deal of diversity, its expression patterns in the CNS were highly conserved in the Drosophila species examined here. In D. melanogaster larva, Crz expression was found in four pairs of neurons per cerebral lobe and in eight pairs of bilateral neurons in the ventral nerve cord; in adult, the number of Crz-producing neurons increased to 6-8 in the pars lateralis of each brain lobe, whereas neurons in the ventral nerve cord were no longer detectable. Crz transcripts were also found in the optic lobes; however, these mRNAs do not seem to be translated. Such adult-like Crz expression patterns were established within 48 hours after pupation. Somata of Crz-neurons in the pars lateralis are located in the vicinity of terminals emanating from PDF-containing pacemaking neurons, indicating a functional connection between the two peptidergic nervous systems. A subset of Crz neurons coexpressed the period clock gene; however, normal Crz transcription was unaffected by central clockworks. Two pairs of ectopic Crz cells were detected in the adult brains of behaviorally arrhythmic Clock(Jrk) or cycle(02) mutants, suggesting that CLOCK and CYCLE proteins negatively regulate Crz transcription in a cell-specific manner.


Subject(s)
Central Nervous System/metabolism , Conserved Sequence/genetics , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Drosophila/metabolism , Genome , Neurons/metabolism , Neuropeptides/genetics , Neuropeptides/metabolism , Animals , Biological Clocks/physiology , Brain/cytology , Brain/metabolism , Cell Differentiation/physiology , Central Nervous System/cytology , Circadian Rhythm/physiology , DNA, Complementary/analysis , DNA, Complementary/genetics , Drosophila/cytology , Drosophila/genetics , Ganglia, Invertebrate/cytology , Ganglia, Invertebrate/metabolism , Gene Expression Regulation/physiology , Molecular Sequence Data , Neurons/cytology , Nuclear Proteins/metabolism , Period Circadian Proteins , Pupa/cytology , Pupa/growth & development , Pupa/metabolism , Sequence Homology, Amino Acid , Sequence Homology, Nucleic Acid , Species Specificity
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