The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Denis Terver - One of the best experts on this subject based on the ideXlab platform.
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Real-time biomonitoring of water contamination by cyanide based on analysis of the continuous electric signal emitted by a Tropical Fish: Apteronotus albifrons
Water Research, 1996Co-Authors: Marielle Thomas, André Florion, Didier Chrétien, Denis TerverAbstract:A new early warning system for monitoring the quality of water was developed using the information conveyed by the continuous electric organ discharges of the Tropical Fish Apteronotus albifrons (Gymnotiformes, family Apteronotidae). The principle is based on the time characterisation of the electric signal emitted by the Fish and uses the fact that the frequency and the form of the signal vary as a function of the physico chemical quality of the ambient water. Eight test Fish were individually confined in a heat-proof test chamber in which a continuous water current, thermo-regulated at 27°C, was maintained. The electric signal sampled over 1 s periods were amplified. The computer processed the signals and their frequencies and determined the coordinates of the points where the temperatures were recorded. The results of the A. albifrons electrical activity were then visualised on a visual display unit. Subsequent mathematical processing helped to detect unusual electrical behaviour (crossing of lower and upper bounds). To illustrate the principle of this new early warning system, the electric response of the A. albifrons exposed to cyanide was tested and compared with the detection thresholds of other biological early warning systems. A, albifrons is able to detect a cyanide concentration of 34.6 μgl-1in less than half an hour. The recorded results suggest that this new-biomonitor corresponds very well with the requirements of warning stations for surface waters subject to cyanide pollution.
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Real-Time Detection of Potassium Cyanide Pollution in Surface Waters Using Electric Organ Discharges Wave Emitted by the Tropical Fish, Apteronotus Albifrons
Environmental Technology, 1996Co-Authors: Marielle Thomas, André Florion, Didier Chrétien, Denis TerverAbstract:A new biological early warning system which exploits the electric organ discharges (EOD) of the South American Tropical Fish Apteronotus albifrons (Gymnotiformes) is described. Thanks to its neurogenic electric organ, this Fish continually emits wave form electric signals. The time variations of the EOD frequency and wave form, two characteristics known to be very stable under constant ambient conditions, were recorded and analysed in a closed circuit to derive therefrom an assessment of the ability of A. albifrons to detect the presence of potassium cyanide. The ultimate aim is to incorporate the technique into a system for detecting changes in the quality of surface waters. The KCN detection threshold was found to be 35 µg.L−1. The response times in 50 % of Fish sensors to detect the different cyanide concentrations tested (i.e. 35, 45, 70, 125 and 180 µg.L−1) were always shorter than half an hour. Minor cyanide concentrations provoked a fall in the EOD frequency while the number of pulses emitted per s...
E. J. T. Melo - One of the best experts on this subject based on the ideXlab platform.
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Evolution of cadmium effects in the testis and sperm of the Tropical Fish Gymnotus carapo.
Tissue & cell, 2015Co-Authors: C. S. Vergilio, C. E. V. Carvalho, R. V. Moreira, E. J. T. MeloAbstract:The present study investigated the testis and sperm morphology of the Tropical Fish Gymnotus carapo after exposure to increasing CdCl2 concentrations (5-40 μM) for 24 and 96 h. The treatments induced Cd accumulation in the testis and a decrease in the gonadosomatic index from a 10 μM. Cd induced alterations in testis since 24h; however the extension and severity of damages increased after 96 h in all tested concentrations. Marked variations in the cysts size, proliferation of the interstitial tissue, infiltration of inflammatory cells, necrosis, reduction of germ cells and sperm aggregation was observed in 96 h treated Fishes. In this time, there was a complete absence of germ cells in the testis of Fish treated with 40 μM. The ultrastructural analysis allowed for the visualization of the initial damages over germ cells, such as the presence of vacuoles in the cytoplasm of spermatogonia, spermatocytes, and spermatids. Exposed Fish (20 μM for 24 and 96 h) had alterations in sperm number and morphology. These results are important for establishing a direct correlation between the Cd accumulation and incidence of damages and can help characterize the mechanism of Cd-induced pathogenesis in the male reproductive system.
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Effects of in vitro exposure to mercury on male gonads and sperm structure of the Tropical Fish tuvira Gymnotus carapo (L.)
Journal of fish diseases, 2013Co-Authors: C. S. Vergilio, C. E. V. Carvalho, R. V. Moreira, E. J. T. MeloAbstract:This study investigated the progressive effects of HgCl2 in the testis and sperm of the Tropical Fish tuvira Gymnotus carapo L. exposed to increasing Hg concentrations (5-30 μm) and increasing exposure times (24-96 h). Histopathology and metal concentrations in the testis were observed. Hg concentrations in the testis reached 5.1 and 5.2 μg g(-1) in Fish exposed to 20 and 30 μm of Hg, respectively. Hg effects on testicular tissue were observed even at low Hg concentrations, with no alterations in gonadosomatic index. However, the quantitative analysis of the induced alterations (lesion index) demonstrated that the Hg effects in testis became more severe after exposure to higher concentrations (20 and 30 μm) and during longer exposure (72 and 96 h), probably leading to partial or total loss of the organ function. Hg exposure (20 μm) also affected sperm count and altered sperm morphology. This study showed that HgCl2 caused progressive damage to testicular tissue, reduced sperm count and altered sperm morphology. These results are important in establishing a direct correlation between Hg accumulation and severity of lesions.
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Accumulation and Histopathological Effects of Mercury Chloride after Acute Exposure in Tropical Fish Gymnotus carapo
Journal of Chemical Health Risks, 2012Co-Authors: C. S. Vergilio, C. E. V. Carvalho, E. J. T. MeloAbstract:The present study evaluated potential Hg bioaccumulation and its morphological effects in different organs of the Tropical Fish, Gymnotus carapo, after a single acute intra-peritoneal exposure (0.6 µg.g -1 ) and over progressively longer exposure times (24 h, 48 h, 72 h and 96 h). The Hg accumulation was differential and time dependent for most target organs (testis > liver > gills > muscle). Hg exposure leads the highest accumulation potential in testis since the initial examination point (24 h) until the last (96 h). The liver showed progressive Hg accumulation, presenting its highest levels only at the 96 h exposure point. Hg concentrations in the gills and muscle oscillated over the exposure times; however, the highest values of both organs also occurred in 96 h exposed Fish. Histopathological alterations were observed in testis, liver and gills from 24 h of Hg exposure, and the extent of the alterations and their severity increased out to 96 h of exposure. These results shows a correlation between Hg accumulation and the induced morphological damages in different organs along the time in a Tropical Fish species G. carapo, being the histopathology a sensitive technique for the observation of the initial damage from Hg exposure.
Marielle Thomas - One of the best experts on this subject based on the ideXlab platform.
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Real-time biomonitoring of water contamination by cyanide based on analysis of the continuous electric signal emitted by a Tropical Fish: Apteronotus albifrons
Water Research, 1996Co-Authors: Marielle Thomas, André Florion, Didier Chrétien, Denis TerverAbstract:A new early warning system for monitoring the quality of water was developed using the information conveyed by the continuous electric organ discharges of the Tropical Fish Apteronotus albifrons (Gymnotiformes, family Apteronotidae). The principle is based on the time characterisation of the electric signal emitted by the Fish and uses the fact that the frequency and the form of the signal vary as a function of the physico chemical quality of the ambient water. Eight test Fish were individually confined in a heat-proof test chamber in which a continuous water current, thermo-regulated at 27°C, was maintained. The electric signal sampled over 1 s periods were amplified. The computer processed the signals and their frequencies and determined the coordinates of the points where the temperatures were recorded. The results of the A. albifrons electrical activity were then visualised on a visual display unit. Subsequent mathematical processing helped to detect unusual electrical behaviour (crossing of lower and upper bounds). To illustrate the principle of this new early warning system, the electric response of the A. albifrons exposed to cyanide was tested and compared with the detection thresholds of other biological early warning systems. A, albifrons is able to detect a cyanide concentration of 34.6 μgl-1in less than half an hour. The recorded results suggest that this new-biomonitor corresponds very well with the requirements of warning stations for surface waters subject to cyanide pollution.
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Real-Time Detection of Potassium Cyanide Pollution in Surface Waters Using Electric Organ Discharges Wave Emitted by the Tropical Fish, Apteronotus Albifrons
Environmental Technology, 1996Co-Authors: Marielle Thomas, André Florion, Didier Chrétien, Denis TerverAbstract:A new biological early warning system which exploits the electric organ discharges (EOD) of the South American Tropical Fish Apteronotus albifrons (Gymnotiformes) is described. Thanks to its neurogenic electric organ, this Fish continually emits wave form electric signals. The time variations of the EOD frequency and wave form, two characteristics known to be very stable under constant ambient conditions, were recorded and analysed in a closed circuit to derive therefrom an assessment of the ability of A. albifrons to detect the presence of potassium cyanide. The ultimate aim is to incorporate the technique into a system for detecting changes in the quality of surface waters. The KCN detection threshold was found to be 35 µg.L−1. The response times in 50 % of Fish sensors to detect the different cyanide concentrations tested (i.e. 35, 45, 70, 125 and 180 µg.L−1) were always shorter than half an hour. Minor cyanide concentrations provoked a fall in the EOD frequency while the number of pulses emitted per s...
C. S. Vergilio - One of the best experts on this subject based on the ideXlab platform.
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Evolution of cadmium effects in the testis and sperm of the Tropical Fish Gymnotus carapo.
Tissue & cell, 2015Co-Authors: C. S. Vergilio, C. E. V. Carvalho, R. V. Moreira, E. J. T. MeloAbstract:The present study investigated the testis and sperm morphology of the Tropical Fish Gymnotus carapo after exposure to increasing CdCl2 concentrations (5-40 μM) for 24 and 96 h. The treatments induced Cd accumulation in the testis and a decrease in the gonadosomatic index from a 10 μM. Cd induced alterations in testis since 24h; however the extension and severity of damages increased after 96 h in all tested concentrations. Marked variations in the cysts size, proliferation of the interstitial tissue, infiltration of inflammatory cells, necrosis, reduction of germ cells and sperm aggregation was observed in 96 h treated Fishes. In this time, there was a complete absence of germ cells in the testis of Fish treated with 40 μM. The ultrastructural analysis allowed for the visualization of the initial damages over germ cells, such as the presence of vacuoles in the cytoplasm of spermatogonia, spermatocytes, and spermatids. Exposed Fish (20 μM for 24 and 96 h) had alterations in sperm number and morphology. These results are important for establishing a direct correlation between the Cd accumulation and incidence of damages and can help characterize the mechanism of Cd-induced pathogenesis in the male reproductive system.
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Effects of in vitro exposure to mercury on male gonads and sperm structure of the Tropical Fish tuvira Gymnotus carapo (L.)
Journal of fish diseases, 2013Co-Authors: C. S. Vergilio, C. E. V. Carvalho, R. V. Moreira, E. J. T. MeloAbstract:This study investigated the progressive effects of HgCl2 in the testis and sperm of the Tropical Fish tuvira Gymnotus carapo L. exposed to increasing Hg concentrations (5-30 μm) and increasing exposure times (24-96 h). Histopathology and metal concentrations in the testis were observed. Hg concentrations in the testis reached 5.1 and 5.2 μg g(-1) in Fish exposed to 20 and 30 μm of Hg, respectively. Hg effects on testicular tissue were observed even at low Hg concentrations, with no alterations in gonadosomatic index. However, the quantitative analysis of the induced alterations (lesion index) demonstrated that the Hg effects in testis became more severe after exposure to higher concentrations (20 and 30 μm) and during longer exposure (72 and 96 h), probably leading to partial or total loss of the organ function. Hg exposure (20 μm) also affected sperm count and altered sperm morphology. This study showed that HgCl2 caused progressive damage to testicular tissue, reduced sperm count and altered sperm morphology. These results are important in establishing a direct correlation between Hg accumulation and severity of lesions.
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Accumulation and Histopathological Effects of Mercury Chloride after Acute Exposure in Tropical Fish Gymnotus carapo
Journal of Chemical Health Risks, 2012Co-Authors: C. S. Vergilio, C. E. V. Carvalho, E. J. T. MeloAbstract:The present study evaluated potential Hg bioaccumulation and its morphological effects in different organs of the Tropical Fish, Gymnotus carapo, after a single acute intra-peritoneal exposure (0.6 µg.g -1 ) and over progressively longer exposure times (24 h, 48 h, 72 h and 96 h). The Hg accumulation was differential and time dependent for most target organs (testis > liver > gills > muscle). Hg exposure leads the highest accumulation potential in testis since the initial examination point (24 h) until the last (96 h). The liver showed progressive Hg accumulation, presenting its highest levels only at the 96 h exposure point. Hg concentrations in the gills and muscle oscillated over the exposure times; however, the highest values of both organs also occurred in 96 h exposed Fish. Histopathological alterations were observed in testis, liver and gills from 24 h of Hg exposure, and the extent of the alterations and their severity increased out to 96 h of exposure. These results shows a correlation between Hg accumulation and the induced morphological damages in different organs along the time in a Tropical Fish species G. carapo, being the histopathology a sensitive technique for the observation of the initial damage from Hg exposure.
Gavin A. Begg - One of the best experts on this subject based on the ideXlab platform.
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Tropical Fish Otoliths: Information for Assessment, Management and Ecology - Tropical Fish otoliths : information for assessment, management and ecology
Reviews: Methods and Technologies in Fish Biology and Fisheries, 2009Co-Authors: Bridget S. Green, Bruce D. Mapstone, Gary Carlos, Gavin A. BeggAbstract:to Otoliths and Fisheries in the Tropics.- Ageing in Coral Reef Fishes: Do we Need to Validate the Periodicity of Increment Formation for every species of Fish for which we collect age-based Demographic Data?.- Age in Years from Otoliths of Adult Tropical Fish.- Daily Otolith Increments in the Early Stages of Tropical Fish.- Alternatives to Sectioned Otoliths: The use of other Structures and Chemical Techniques to Estimate Age and Growth for Marine Vertebrates and Invertebrates.- The Back-Calculation of Fish Growth From Otoliths.- Otolith Microstructure in Tropical Fish.- Otolith Chemistry.- Tropical Otoliths - Where to Next?.- Alternatives to Sectioned Otoliths: The use of other Structures and Chemical Techniques to Estimate Age and Growth for Marine Vertebrates and Invertebrates.
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Comprar Tropical Fish Otoliths: Information for Assessment, Management and Ecology | Green, Bridget S. | 9781402035821 | Springer
2009Co-Authors: Bridget S. Green, Bruce D. Mapstone, Gary Carlos, Gavin A. BeggAbstract:Tienda online donde Comprar Tropical Fish Otoliths: Information for Assessment, Management and Ecology al precio 250,07 € de Green, Bridget S. | Mapstone, Bruce D. | Carlos, Gary | Begg, Gavin A., tienda de Libros de Medicina, Libros de Biologia - Zoologia
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Tropical Fish Otoliths: Information for Assessment, Management and Ecology - Tropical Fish otoliths : information for assessment, management and ecology
Reviews: Methods and Technologies in Fish Biology and Fisheries, 2009Co-Authors: Bridget S. Green, Bruce D. Mapstone, Gary Carlos, Gavin A. BeggAbstract:Techniques and theory for processing otoliths from Tropical marine Fish have developed only recently due to an historic misconception that these organisms could not be aged. Otoliths are the most commonly used structures from which daily, seasonal or annual records of a Fish’s environmental history are inferred, and are also used as indicators of migration patterns, home range, spatial distribution, stock structure and life history events. A large proportion of projects undertaken on Tropical marine organisms involve removal and processing of calcified structures such as otoliths, statoliths or vertebrae to retrieve biological, biochemical or genetic information. Current techniques and principles have evolved rapidly and are under constant modification and these differ among laboratories, and more particularly among species and within life history stages. Tropical Fish otoliths: Information for assessment, management and ecology is a comprehensive description of the current status of knowledge about otoliths in the tropics. This book has contributions from leading experts in the field, encompasing a Tropical perspective on daily and annual ageing in Fish and invertebrates, microchemistry, interpreting otolith microstructure and using it to back-calculate life history events, and includes a treatise on the significance of validating periodicity in otoliths.
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Tropical Fish otoliths information for assessment management and ecology
2009Co-Authors: Bridget S. Green, Bruce D. Mapstone, Gary Carlos, Gavin A. BeggAbstract:Techniques and theory for processing otoliths from Tropical marine Fish have developed only recently due to an historic misconception that these organisms could not be aged. Otoliths are the most commonly used structures from which daily, seasonal or annual records of a Fish’s environmental history are inferred, and are also used as indicators of migration patterns, home range, spatial distribution, stock structure and life history events. A large proportion of projects undertaken on Tropical marine organisms involve removal and processing of calcified structures such as otoliths, statoliths or vertebrae to retrieve biological, biochemical or genetic information. Current techniques and principles have evolved rapidly and are under constant modification and these differ among laboratories, and more particularly among species and within life history stages. Tropical Fish otoliths: Information for assessment, management and ecology is a comprehensive description of the current status of knowledge about otoliths in the tropics. This book has contributions from leading experts in the field, encompasing a Tropical perspective on daily and annual ageing in Fish and invertebrates, microchemistry, interpreting otolith microstructure and using it to back-calculate life history events, and includes a treatise on the significance of validating periodicity in otoliths.