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Zunyao Wang - One of the best experts on this subject based on the ideXlab platform.
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the ph dependent toxicity of triclosan to five aquatic organisms daphnia magna photobacterium phosphoreum danio rerio Limnodrilus hoffmeisteri and carassius auratus
Environmental Science and Pollution Research, 2018Co-Authors: Jing Chen, Shuo Zhang, Ahmed A Allam, Jamaan S Ajarem, Zunyao WangAbstract:Triclosan (TCS) is an antibacterial and antifungal agent widely used in personal care products, and it has been frequently detected in the aquatic environment. In the present study, the acute toxicity of TCS to Daphnia magna, Photobacterium phosphoreum, Danio rerio, and Limnodrilus hoffmeisteri was assessed under different pH conditions. Generally, TCS was more toxic to the four aquatic organisms in acidic medium. The LC50 values for D. magna and D. rerio were smaller among the selected species, suggesting that D. magna and D. rerio were more sensitive to TCS. In addition, the oxidative stress-inducing potential of TCS was evaluated in Carassius auratus at three pH values. Changes of superoxide dismutase (SOD) and catalase (CAT) activity, glutathione (GSH) level, and malondialdehyde (MDA) content were commonly observed in all TCS exposure groups, indicating the occurrence of oxidative stress in the liver of C. auratus. The integrated biomarker response (IBR) index revealed that a high concentration of TCS induced great oxidative stress in goldfish under acidic condition. This work supplements the presently available data on the toxicity data of TCS, which would provide some useful information for the environmental risk assessment of this compound.
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the toxic effect and bioaccumulation in aquatic oligochaete Limnodrilus hoffmeisteri after combined exposure to cadmium and perfluorooctane sulfonate at different ph values
Chemosphere, 2016Co-Authors: Jiaoqin Liu, Liansheng Wang, Zunyao WangAbstract:Cadmium (Cd) and Perfluorooctane sulfonate (PFOS) have been detected in aquatic environment. In this study, we investigated the acute effect, bioaccumulation and oxidative stress status in the aquatic oligocheate Limnodrilus hoffmeisteri after exposure to Cd and PFOS at different pH values. In the studied pH range, acute Cd toxicity was significantly enhanced with pH increasing from 6.2 to 8.0, and the 48h-EC50 of Cd was (significantly) decreased in the presence of PFOS. Bioaccumulation analysis results show that the accumulated Cd/PFOS in single exposure group increased with increasing exposure concentrations, and co-exposure makes internal Cd concentration significantly lowered for Cd(0.1) group at pH 8.0. Significant changes in superoxide dismutase activity, glutathione level and malondialdehyde content were observed in single and combined treatments. Based on IBR value, single Cd and PFOS exposure caused largest damage to the antioxidant defense system at pH 8.0 and pH 6.2, respectively, while the harmful effects of joint exposure were always the “compromise” between single Cd and PFOS exposure. This work could provide useful information for the risk assessment of co-exposure to perfluorinated compounds and heavy metals in natural environment.
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toxicity and bioaccumulation of copper in Limnodrilus hoffmeisteri under different ph values impacts of perfluorooctane sulfonate
Journal of Hazardous Materials, 2016Co-Authors: Lingjun Meng, Jiaoqin Liu, Zunyao Wang, Shaogui Yang, Mingbao Feng, Cheng SunAbstract:Aquatic oligochaete Limnodrilus hoffmeisteri (L. hoffmeisteri) has been commonly used as a lethal and/or sub-lethal toxicological model organism in ecological risk assessments in contaminated water environments. In this study, experiments were conducted to investigate the potential toxic effects of copper (Cu(II)) with or without perfluorooctane sulfonate (PFOS) under different pH values (6.0, 7.0 and 8.0) on LC50, bioaccumulation, and oxidative stress biomarkers in L. hoffmeisteri after 3 and 7 days. The LC50 values of Cu(II) decreased with the increasing pH and the addition of PFOS. After each exposure, increasing bioaccumulation of Cu(II) in L. hoffmeisteri was observed in the combined exposure treatments, whereas the bioaccumulation of PFOS decreased. Moreover, the activity of superoxide dismutase, the level of glutathione, and the content of malondialdehyde were significantly altered after these exposures, possibly indicating that the bioaccumulation of Cu(II) and PFOS caused adverse effects on antioxidant defenses of L. hoffmeisteri. The integrated biomarker response index, indicates that the combined effect was proposed as synergism, which is coincided with the results of toxic unit. Moreover, this work showed that aquatic environment may become more livable when water conditions changed from acidic to near-neutral or alkaline.
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evaluation of single and joint toxicity of perfluorooctane sulfonate and zinc to Limnodrilus hoffmeisteri acute toxicity bioaccumulation and oxidative stress
Journal of Hazardous Materials, 2016Co-Authors: Jiaoqin Liu, Liqing Yan, Liansheng Wang, Zunyao WangAbstract:Perfluorooctane sulfonate (PFOS) and zinc have been detected in aquatic environment widely. In order to study the combined effects of PFOS and Zn, a series of experiments was conducted to explore the acute mortality, bioaccumulation and antioxidant status of Limnodrilus hoffmeisteri. The acute toxicity was evaluated by calculating 24h-EC50 values, and it was observed that 24h-EC50 values in single and joint treatments decreased with decreasing pH value or increasing exposure concentration. Toxic unit analysis suggested that the combined effects of the PFOS+Zn binary mixture were mostly simple addition, with 8 groups showing synergism and only one group showing antagonism. The analysis of internal Zn and PFOS concentration showed that the possible interaction between Zn and PFOS can affect the bioaccumulation of the two chemicals in L. hoffmeisteri. In addition, oxidative stress status was assessed by measuring oxidation-related biochemical parameters such as superoxide dismutase, glutathione peroxidase and malondialdehyde, and the integrated biomarker response index was estimated to rank the toxicity order. Exposures to Zn and PFOS were found to evoke some changes in the antioxidant defense system, and a strong self-adaptive ability was noticed for L. hoffmeisteri after 10 d exposure.
Christer Erseus - One of the best experts on this subject based on the ideXlab platform.
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multi locus phylogenetic analysis of the genus Limnodrilus annelida clitellata naididae
Molecular Phylogenetics and Evolution, 2017Co-Authors: Yingkui Liu, Steven V Fend, Svante Martinsson, Xu Luo, Akifumi Ohtaka, Christer ErseusAbstract:Limnodrilus species are annelid worms distributed worldwide in various freshwater sediments. The systematics of Limnodrilus has chiefly been based on morphology, but the genus has not been subject to any closer phylogenetic studies over the past two decades. To reconstruct the evolutionary history of Limnodrilus, and to assess the monophyly of this genus and its systematic position within the subfamily Tubificinae (Annelida: Clitellata: Naididae), 45 Limnodrilus specimens, representing 19 species, and 35 other naidid species (representing 24 genera) were sampled. The data consisted of sequences of three mitochondrial genes (COI, 12S and 16S rDNA) and four nuclear markers (18S and 28S rDNA, Histone 3, and ITS). The phylogeny was estimated, using Maximum Likelihood and Bayesian analyses of concatenated data of seven DNA loci, as well as a multi-locus coalescent-based approach. All analyses strongly suggest that Limnodrilus is monophyletic, but only if the morphospecies L. rubripenis is removed from it. Limnodrilus rubripenis and (at least) Baltidrilus, Lophochaeta and some species attributed to Varichaetadrilus comprise the sister group to the clade Limnodrilus sensu stricto, and the latter is further divided into three well-supported groups. One of them contains morphospecies characterized by short cuticular penis sheaths and enlarged chaetae in anterior segments (L. udekemianus, L. silvani and L. grandisetosus). The second is a small group of species with moderately long penis sheaths, i.e., L. sulphurensis and L. profundicola. The third, and largest group, includes not only the multitude of cryptic species in the L. hoffmeisteri complex, but also other, morphologically distinct, species nested within this complex. All studied species in this large group have long penis sheaths, which are exceptionally long in L. claparedianus, L. maumeensis, and a form morphologically intermediate between L. claparedianus and L. cervix. The identification and classification of these groups provide a framework for directed sampling in further phylogenetic studies, and for revisionary work on the L. hoffmeisteri complex and other unresolved Limnodrilus species.
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extensive cryptic diversity in the cosmopolitan sludge worm Limnodrilus hoffmeisteri clitellata naididae
Organisms Diversity & Evolution, 2017Co-Authors: Yingkui Liu, Steven V Fend, Svante Martinsson, Christer ErseusAbstract:Limnodrilus hoffmeisteri Claparede, 1862 is a common freshwater worm, often regarded as an indicator of organic pollution. The taxonomic status of this species is controversial due to great variation in morphological features. Numerous morphological forms of L. hoffmeisteri are recorded in the literature, especially from Europe and North America. Today, DNA-based species delimitation assumes that species boundaries can be more objectively and effectively estimated using genetic data rather than with morphological data alone. To investigate if L. hoffmeisteri is a single species, 295 worms identified as either L. hoffmeisteri or other similar (congeneric) morphospecies, using currently accepted morphological criteria, were collected from 82 locations in the northern hemisphere. The number of primary species hypotheses (PSHs) was first explored with cytochrome oxidase subunit I (COI), the proposed DNA barcode for animal species, and with data for all specimens. Both automatic barcoding gap discovery (ABGD) and the Bayesian general mixed Yule coalescent (bGMYC) model revealed the existence of ≥25 distinct PSHs (COI lineages) in our dataset. Then, smaller samples of individuals representing major COI lineages were used for exploration of a nuclear locus, the internal transcribed spacer (ITS) region. In the ITS gene tree (81 sequences), generated by BEAST, 16 well-supported terminal groups were found, but not all of these groups were congruent with the PSHs found in the COI tree. As results across these different analyses were inconsistent, we resorted to analyzing reciprocal monophyly between gene trees and used a minimum consensus of all evidence, suggesting that there are 13 separately evolving lineages (=13 species) within our sample. The smallest uncorrected COI p-distance between these species is 12.1%, and the largest intraspecific p-distance is 16.4%, illustrating the problem of species delimitation with a DNA-barcoding gap as the sole criterion. Ten of these species are morphologically identified as “L. hoffmeisteri,” the remaining three can be attributed to morphologically distinct congeneric species. An individual from the type locality in Switzerland was designated as a neotype of L. hoffmeisteri sensu stricto. This worm belongs to one of the ten species, and this lineage is widely distributed in Europe, Asia, and North America. The remaining nine species show a mixed distribution pattern; some appear to be endemic to a restricted area, others are Holarctic. Our results provide clues to the future revalidation of some of the nominal species today placed in synonymy with L. hoffmeisteri. A BEAST analysis, based on previously published and newly generated 16S data, suggested that this complex contains also other species than those studied by us. By integrating additional genetic data, it will be possible to identify these and additional specimens in future studies of Limnodrilus, and the neotype provides a baseline for further revisions of the taxonomy of the L. hoffmeisteri complex.
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Limnodrilus sulphurensis n sp from a sulfur cave in colorado usa with notes on the morphologically similar l profundicola clitellata naididae tubificinae
Zootaxa, 2016Co-Authors: Steven V Fend, Yingkui Liu, David Steinmann, Olav Giere, Hazel A Barton, Fred Luiszer, Christer ErseusAbstract:A new species of the tubificine genus Limnodrilus is described and COI barcoded from Sulphur Cave and associated springs in Colorado, USA. The habitats are characterized by high sulfide concentrations. The new species, L. sulphurensis , is distinguished from all congeners by the elongate, nearly parallel teeth of chaetae in its anterior segments. It has a penis sheath resembling that of L. profundicola ; consequently, museum specimens and new collections are examined here to resolve some of the taxonomic confusion surrounding that widespread, but uncommon species.
Wenjia Deng - One of the best experts on this subject based on the ideXlab platform.
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effects of chironomid larvae and Limnodrilus hoffmeisteri bioturbation on the distribution and flux of chromium at the sediment water interface
Journal of Environmental Management, 2019Co-Authors: Dandong Cheng, Jinxi Song, Xiaotian Zhao, Shaoqing Wang, Qidong Lin, Jianglin Peng, Wenjia DengAbstract:The impacts of chironomid larvae and the tubificid worm Limnodrilus hoffmeisteri on the distribution and flux of the heavy metal chromium (Cr) across the sediment-water interface were investigated with a 21-day laboratory microcosm experiment. The two studied species feature different bioturbation modes involving bioirrigation and upward bioconveyance. The Cr concentrations in the overlying water and pore water were measured and compared using treatments with bioturbation by a single species and by combinations of both species and a treatment with no organisms. The results indicated that both bioturbation modes significantly increased the Cr concentrations in the overlying water and pore water. The overlying water had lower Cr concentrations than the pore water. Little variation in the Cr concentrations was observed in the treatment without organisms. Both species enhanced the Cr flux from the pore water to the overlying water. The worm treatments had a great impact on the Cr concentration in the overlying water through intensive upward conveyance activity, while the chironomid larvae treatments exerted significant effects on the Cr variation in the pore water and Cr flux across the interface via bioirrigation activity. These findings reveal the importance of bioturbation in biogeochemical processes in freshwater ecosystems.
Ronald P. Hedrick - One of the best experts on this subject based on the ideXlab platform.
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Molecular phylogeny of tubificid oligochaetes with special emphasis on Tubifex tubifex (Tubificidae).
Molecular phylogenetics and evolution, 2001Co-Authors: Katherine A. Beauchamp, Terry S. Mcdowell, R D Kathman, Ronald P. HedrickAbstract:Tubifex tubifex is a cosmopolitan freshwater oligochaete whose presence has been studied as a health indicator of the aquatic environment and as a host for several myxozoan parasites of fish. Unfortunately, current morphological criteria used to distinguish Tubifex spp. (Tubificidae) are inadequate. We therefore developed mitochondrial 16S ribosomal DNA markers to examine phylogenetic relationships among aquatic oligochaetes and to distinguish species of Tubifex that might serve as hosts for a particular myxozoan parasite, Myxobolus cerebralis. Our phylogenetic analyses of oligochaetes based on a 378-bp segment yielded one most parsimonious tree with three major groups that corresponded to the families Lumbricidae, Sparganophilidae, and Tubificidae. T. tubifex and T. ignotus formed a monophyletic assemblage, and a sister relationship between the genera Tubifex and Limnodrilus was strongly supported. A second analysis of the relationship within the genus Tubifex identified six genetically distinct lineages of T. tubifex from North America and Europe that were separated by genetic distances comparable to those found for "well-defined" species of Limnodrilus. Therefore, the existence of several morphologically indistinguishable, thus cryptic, species of Tubifex in North America and Europe is suggested.
Jinxi Song - One of the best experts on this subject based on the ideXlab platform.
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effects of chironomid larvae and Limnodrilus hoffmeisteri bioturbation on the distribution and flux of chromium at the sediment water interface
Journal of Environmental Management, 2019Co-Authors: Dandong Cheng, Jinxi Song, Xiaotian Zhao, Shaoqing Wang, Qidong Lin, Jianglin Peng, Wenjia DengAbstract:The impacts of chironomid larvae and the tubificid worm Limnodrilus hoffmeisteri on the distribution and flux of the heavy metal chromium (Cr) across the sediment-water interface were investigated with a 21-day laboratory microcosm experiment. The two studied species feature different bioturbation modes involving bioirrigation and upward bioconveyance. The Cr concentrations in the overlying water and pore water were measured and compared using treatments with bioturbation by a single species and by combinations of both species and a treatment with no organisms. The results indicated that both bioturbation modes significantly increased the Cr concentrations in the overlying water and pore water. The overlying water had lower Cr concentrations than the pore water. Little variation in the Cr concentrations was observed in the treatment without organisms. Both species enhanced the Cr flux from the pore water to the overlying water. The worm treatments had a great impact on the Cr concentration in the overlying water through intensive upward conveyance activity, while the chironomid larvae treatments exerted significant effects on the Cr variation in the pore water and Cr flux across the interface via bioirrigation activity. These findings reveal the importance of bioturbation in biogeochemical processes in freshwater ecosystems.