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Robert A. Angus - One of the best experts on this subject based on the ideXlab platform.
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triclosan has endocrine disrupting effects in male western mosquitofish Gambusia affinis
Environmental Toxicology and Chemistry, 2010Co-Authors: Samiksha A Raut, Robert A. AngusAbstract:Triclosan (TCS) is an antibacterial agent used in a variety of personal care and industrial products. Triclosan and its environmentally transformed derivative, methyl-TCS, have been detected in waters receiving effluent from public wastewater treatment plants. Previous studies have demonstrated that TCS has the potential to act as an endocrine disruptor. The present study tested the hypothesis that TCS acts as an endocrine-disrupting agent in fish. Mature male western mosquitofish, Gambusia affinis, were exposed to TCS concentrations of 100, 200, and 350 nM (29.0, 57.9, and 101.3 µg/L) for 35 d by the static renewal method. Induction of the normally female-limited vitellogenin gene expression and reduction in sperm count were quantified as biomarkers of endocrine disruption. Vitellogenin mRNA expression was significantly elevated in the 350 nM TCS treatment. Sperm counts in the same treatment group were significantly decreased. The mean hepatosomatic index in the 350 nM treatment group was significantly increased. This study demonstrates that TCS has the potential to act as an endocrine disruptor in male mosquitofish. Environ. Toxicol. Chem. 2010;29:1287–1291. © 2010 SETAC
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effects of 17α ethynylestradiol on sexual development of male western mosquitofish Gambusia affinis
Comparative Biochemistry and Physiology C-toxicology & Pharmacology, 2005Co-Authors: Robert A. Angus, Jason Stanko, Ronald L Jenkins, Douglas R WatsonAbstract:Abstract Juvenile male western mosquitofish (Gambusia affinis) were exposed to different concentrations of 17α-ethynyl estradiol (EE2) in the diet during the period of sexual maturation. A clear inhibiting influence of EE2 on sexual development was apparent. The proportion of males in each treatment group that failed to complete gonopodial development during the 150-day observation period increased significantly with EE2 concentration. There were significant nonlinear trends toward shorter gonopodia in groups exposed to higher EE2 concentrations. Vitellogenin (VTG) was detectable in the blood of all fish exposed to 1.0 or more μg EE2/g food and the concentration increased dramatically with increasing EE2 exposure. A significant negative association was seen between EE2 concentration and spermatophore counts. This study has demonstrated deleterious effects of EE2 exposure on sexual maturation and several indirect measures of reproductive fitness. It supports the biological relevance of vitellogenin in the blood and reduced gonopodium length as biomarkers for estrogen exposure and endocrine disruption in mosquitofish.
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Mosquitofish (Gambusia affinis) vitellogenin: identification, purification, and immunoassay
Comparative Biochemistry and Physiology C-toxicology & Pharmacology, 2001Co-Authors: Joseph F. Tolar, Amy R. Mehollin, R. Douglas Watson, Robert A. AngusAbstract:Abstract Vitellogenin is a phospholipoglycoprotein precursor of egg yolk. In mature female fish, vitellogenin is synthesized and secreted by the liver in response to circulating estrogens. Vitellogenin is normally undetectable in the blood of male fish, but can be induced by exposure to compounds possessing estrogenic activity. Thus, the presence of vitellogenin in blood of male fish can serve as a useful biomarker for assessing previous exposure to estrogenic compounds. In the present study, we report identification and purification of vitellogenin in the mosquitofish (Gambusia affinis). Anti-vitellogenin immune serum was generated and used to develop an immunoblot assay for detection of vitellogenin. A combination of immunoblotting and densitometric scanning was used to assess the time- and dose-dependent effects of 17α-ethynylestradiol on vitellogenesis in male G. affinis. The results indicate that changes in the level of vitellogenin in mosquitofish blood can be reliably detected by the immunoblot assay, and that the mosquitofish may be a useful bioindicator organism for detecting estrogenic contamination of the aquatic environment.
Prasad Rn - One of the best experts on this subject based on the ideXlab platform.
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Control of mosquito breeding through Gambusia affinis in rice fields.
Indian journal of malariology, 1993Co-Authors: Prasad H, Prasad RnAbstract:: Studies on mosquito breeding and its control through Gambusia affinis in nursery and paddy fields after transplantation of seedlings were carried out during June to October 1991 in about 10 ha rice field area. Six anopheline species, viz. An. culicifacies, An. annularis, An. subpictus, An. nigerrimus, An. barbirostris and An. aconitus, and four culicine species, viz. Cx. tritaeniorhynchus, Cx. bitaeniorhynchus, Cx. quinquefasciatus, and Aedes sp. could be identified. These were found breeding in rice fields with fluctuations in their percentage composition, exhibiting species succession in different months. G. affinis survived well in submerged rice fields and provided 87.8% mosquito larval control. In rice fields which exhibited intermittent drying up leading to formation of pools, puddles etc., moderate larval control was achieved. However, in nursery rice fields, this method was not applicable. Mosquito larval control through larvivorous fish in rice fields can be achieved but the method has limitations.
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Culture of Gambusia affinis with food fishes.
Indian journal of malariology, 1991Co-Authors: Prasad H, Prasad RnAbstract:: Culture of Gambusia affinis along with carps in fish culture practice in village ponds in Shahjahanpur distt., U.P., has revealed very little difference in fish productivity (1539 kg/ha in ponds with Gambusia, 1572 kg/ha in ponds without Gambusia). The growth and survival of Gambusia were found to be good in most of the composite fish culture ponds. Culture of Gambusia along with edible fish in village ponds is, therefore, recommended to get the dual benefit of fish production and control of mosquito proliferation in village ponds.
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Evaluation of mosquito fish Gambusia affinis in the control of mosquito breeding in rice fields.
Indian journal of malariology, 1991Co-Authors: Das Mk, Prasad RnAbstract:: The mosquito control potential of Gambusia affinis, a mosquito fish, was evaluated in rice fields in the Shahjahanpur district of Uttar Pradesh. This fish, at a stocking rate of 5 fishes/sq m, significantly reduced the larval and pupal densities in experimental fields as compared to control fields during the entire observation period of 42 days. Control of mosquito breeding in rice fields through this fish seems to be promising.
James W Petranka - One of the best experts on this subject based on the ideXlab platform.
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chemicals of predatory mosquitofish Gambusia affinis influence selection of oviposition site by culex mosquitoes
Journal of Chemical Ecology, 2002Co-Authors: Kim A Angelon, James W PetrankaAbstract:Ovipositing insects may avoid aquatic sites where there is high predation risk to their offspring, but the proximate mechanisms that mediate avoidance behavior are poorly resolved. We conducted an experiment to determine whether mosquitoes would reduce oviposition rates in pools containing chemicals of the mosquitofish (Gambusia affinis), a voracious predator that is widely employed to control mosquitoes. Experimental treatments consisted of outdoor pools that contained known concentrations of fish chemicals (low, medium, or high) or no fish chemicals (control). The pools were arranged in a randomized block design, and the number of mosquito larvae in each pool served as the response variable to estimate relative oviposition rate. Members of the Culex pipiens complex were the main colonizers of the pools. The mean number of larvae per pool differed among treatments (P = 0.026) and was about three times greater in control pools compared with those receiving medium and high concentrations of fish chemicals. Pairwise comparisons indicate that only medium and high treatments differed significantly from controls, suggesting that a threshold concentration exists below which mosquitoes cannot reliably detect predators. Our data suggest that the effectiveness of Gambusia affinis in controlling mosquitoes may be compromised if adult mosquitoes respond to fish stocking by shifting to nearby breeding sites that lack fish. We discuss issues concerning the use of Gambusia in biological control programs within the context of these new findings.
Samiksha A Raut - One of the best experts on this subject based on the ideXlab platform.
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triclosan has endocrine disrupting effects in male western mosquitofish Gambusia affinis
Environmental Toxicology and Chemistry, 2010Co-Authors: Samiksha A Raut, Robert A. AngusAbstract:Triclosan (TCS) is an antibacterial agent used in a variety of personal care and industrial products. Triclosan and its environmentally transformed derivative, methyl-TCS, have been detected in waters receiving effluent from public wastewater treatment plants. Previous studies have demonstrated that TCS has the potential to act as an endocrine disruptor. The present study tested the hypothesis that TCS acts as an endocrine-disrupting agent in fish. Mature male western mosquitofish, Gambusia affinis, were exposed to TCS concentrations of 100, 200, and 350 nM (29.0, 57.9, and 101.3 µg/L) for 35 d by the static renewal method. Induction of the normally female-limited vitellogenin gene expression and reduction in sperm count were quantified as biomarkers of endocrine disruption. Vitellogenin mRNA expression was significantly elevated in the 350 nM TCS treatment. Sperm counts in the same treatment group were significantly decreased. The mean hepatosomatic index in the 350 nM treatment group was significantly increased. This study demonstrates that TCS has the potential to act as an endocrine disruptor in male mosquitofish. Environ. Toxicol. Chem. 2010;29:1287–1291. © 2010 SETAC
J Albaiges - One of the best experts on this subject based on the ideXlab platform.
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monitoring of organophosphorus and organochlorinated compounds in a rice crop field ebro delta spain using the mosquitofish Gambusia affinis as indicator organism
Chemosphere, 1992Co-Authors: Cinta Porte, Damia Barcelo, J AlbaigesAbstract:Abstract Individual PCB congeners and organophosphorus pesticides were determined in the muscular tissue of the mosquitofish Gambusia affinis from a rice crop field (Ebro Delta, Spain). Variations in the accumulation patterns of both classes of chemicals were investigated along a year and related to biological constraints of the organisms (e.g. sex and reproduction cycle), environmental conditions (e.g. water flow and pesticide applications) and the physicochemical characteristics of the pollutants. Gambusia affinis showed a rather fast response against the occurrence of these contaminants in the rice crop field, although its biological cycle has a significant influence on the bioaccumulation of the more lipophilic species (e.g. PCBs).
