| copper/zinc superoxide dismutase from the cladoceran daphnia magna: molecular cloning and expression in response to different acute environmental stressors. | the copper/zinc superoxide dismutase (cu/zn-sod) is a representative antioxidant enzyme that is responsible for the conversion of superoxide to oxygen and hydrogen peroxide in aerobic organisms. cu/zn-sod mrnas have been cloned from many species and employed as useful biomarkers of oxidative stresses. in the present study, we cloned cu/zn-sod cdna from the cladoceran daphnia magna, analyzed its catalytic properties, and investigated mrna expression patterns after exposure to known oxidative stre ... | 2013 | 23815380 |
| prey selection by mosquitofish (gambusia affinis) in california rice fields: effect of vegetation and prey species. | mosquitofish are widely used for biological control of mosquito larvae in rice fields, but the presence of different types of vegetation or alternative arthropod prey affects the performance of the fish. feeding experiments were conducted in 4 rice field vegetation zones. overall, predation was maximal in young and mature rice, moderate in the submerged naiad vegetation, and minimal in areas of open water. a preference for fourth instar culex tarsalis mosquito larvae over daphnia pulex and the a ... | 1990 | 2324716 |
| cardioacceleratory function of the neurohormone ccap in the mosquito anopheles gambiae. | crustacean cardioactive peptide (ccap) is a highly conserved arthropod neurohormone that is involved in ecdysis, hormone release and the modulation of muscle contractions. here, we determined the ccap gene structure in the malaria mosquito anopheles gambiae, assessed the developmental expression of ccap and its receptor and determined the role that ccap plays in regulating mosquito cardiac function. race sequencing revealed that the a. gambiae ccap gene encodes a neuropeptide that shares 100% am ... | 2013 | 23364571 |
| evaluating mosquito control pesticides for effect on target and nontarget organisms. | recent requirements for biomonitoring of urban stormwater runoff have raised the issue of toxic contributions from mosquito control products. a comparison of seven pesticides for their toxicity to target and nontarget organisms was conducted in field and laboratory trials to determine relative impacts in and around craighead county, arkansas. twenty-four and forty-eight-hour acute toxicity tests using ceriodaphnia dubia, daphnia magna, daphnia pulex, and pimephales promelas were employed with u. ... | 2000 | 10948282 |
| cloning and expression analysis of a transformer gene in daphnia pulex during different reproduction stages. | the full-length cdna of a transformer gene (dptra) was cloned from the cladoceran daphnia pulex using race. dptra expression was assessed by qpcr and whole-mount in situ hybridization in different reproductive stages. the dptra cdna, 1652bp in length, has a 1158-bp open reading frame that encodes a 385 amino acid polypeptide containing one sex determination protein n terminal (sdp_n) superfamily, eight putative phosphorylation sites, and an arginine-serine (rs)-rich domain at the n-terminus. dpt ... | 2014 | 24725535 |
| cardiac contractility structure-activity relationship and ligand-receptor interactions; the discovery of unique and novel molecular switches in myosuppressin signaling. | peptidergic signaling regulates cardiac contractility; thus, identifying molecular switches, ligand-receptor contacts, and antagonists aids in exploring the underlying mechanisms to influence health. myosuppressin (ms), a decapeptide, diminishes cardiac contractility and gut motility. myosuppressin binds to g protein-coupled receptor (gpcr) proteins. two drosophila melanogaster myosuppressin receptors (drmms-rs) exist; however, no mechanism underlying ms-r activation is reported. we predicted dr ... | 2015 | 25793503 |
| genome-wide analysis of tandem repeats in daphnia pulex--a comparative approach. | dna tandem repeats (trs) are not just popular molecular markers, but are also important genomic elements from an evolutionary and functional perspective. for various genomes, the densities of short tr types were shown to differ strongly among different taxa and genomic regions. in this study we analysed the tr characteristics in the genomes of daphnia pulex and 11 other eukaryotic species. characteristics of trs in different genomic regions and among different strands are compared in details for ... | 2010 | 20433735 |
| characterization of a membrane-bound angiotensin-converting enzyme isoform in crayfish testis and evidence for its release into the seminal fluid. | in the present study, an isoform of angiotensin-converting enzyme was characterized from the testis of a decapod crustacean, the crayfish astacus leptodactylus. angiotensin-converting enzyme cdna, obtained by 3'- to 5' race of testis rnas, codes for a predicted one-domain protein similar to the mammalian germinal isoform of angiotensin-converting enzyme. all amino acid residues involved in enzyme activity are highly conserved, and a potential c-terminus transmembrane anchor may be predicted from ... | 2009 | 19656189 |
| acute toxicity assessment of azadirachtin-based pesticides using murine hybridoma and oyster cells. | in vitro acute toxicities of azadirachtin-containing pesticides (neemix and bioneem), formulated with neem tree extracts, and pure azadirachtin (aza), the believed active ingredient, were studied using hybridoma and oyster cells and were compared to results obtained using the standard in vivo daphnia pulex toxicity assay. neem-based pesticides showed relatively high toxicity to both hybridoma and oyster cells at concentrations of 1 microg aza/ml and higher. the ic50 values for hybridoma cells we ... | 2003 | 12617555 |
| comparative toxicity of two azadirachtin-based neem pesticides to daphnia pulex. | azadirachtin (aza)-based pesticides (neemix and bioneem) demonstrated toxicity in 48-h nonrenewal toxicity assays using daphnia pulex at levels that were comparable with several organophosphate pesticides. the median lethal concentration (lc50) values for the two neem pesticides were found to be 0.028 and 0.033 microl/ml, respectively. the lc50 value for nonformulated (95% pure) aza was determined to be 0.382 microg aza/ml. neemix and bioneem were exposed to air and northern sky daylight in a li ... | 2002 | 11804058 |
| population-level effects of the neem insecticide, neemix, on daphnia pulex. | although natural insecticides from the neem tree are generally perceived as less harmful to the environment than synthetic insecticides, new evidence indicates that these products may pose a risk to certain nontarget organisms. in this paper, acute and chronic effects of commercial neem insecticides on the aquatic invertebrate, daphnia pulex were examined. the acute toxicity of two commercial neem insecticides, neemix, azatin and the experimental insecticide, rh-9999 to d. pulex was investigated ... | 2001 | 11495023 |
| native and non-native plants provide similar refuge to invertebrate prey, but less than artificial plants. | non-native species introductions are widespread and can affect ecosystem functioning by altering the structure of food webs. invading plants often modify habitat structure, which may affect the suitability of vegetation as refuge and could thus impact predator-prey dynamics. yet little is known about how the replacement of native by non-native vegetation affects predator-prey dynamics. we hypothesize that plant refuge provisioning depends on (1) the plant's native status, (2) plant structural co ... | 2015 | 25885967 |
| molecular connectivity indices for predicting bioactivities of substituted nitrobenzene and aniline compounds. | bioconcentration and toxicity of 22 substituted nitrobenzene and aniline compounds to aquatic organisms were assessed with quantitative structure-activity relationship (qsar). acute toxicities of aquatic organisms, including daphnia (daphnia pulex) and carp (cyprinus carpio), to 22 chemicals have been determined in our previous work. in this study, the bioconcentration factors (bcfs) for carp were further investigated. by the use of multiple-regression analyses, the molecular connectivity indice ... | 2009 | 19423164 |
| the acute toxicity of thallium to freshwater organisms: implications for risk assessment. | the acute toxicity of tl(i) to the microalga, pseudokirchneriella subcapitata, the planktonic crustaceans, daphnia magna and daphnia pulex, and early-life stage of the zebrafish, danio rerio, has been studied according to oecd protocols. toxicological end-point concentrations for the microalga ranged from 17 μg l(-1) for a 72 h eyc25 (yield inhibition) to 80 μg l(-1) for a 72 h erc50 (growth inhibition). daphnia were less sensitive to tl, with 48 h ec50s of about 1000 μg l(-1) and 1200 μg l(-1) ... | 2015 | 26225743 |
| molecular docking: a potential tool to aid ecotoxicity testing in environmental risk assessment of pharmaceuticals. | a cocktail of human pharmaceuticals pollute aquatic environments and there is considerable scientific uncertainty about the effects that this may have on aquatic organisms. human drug target proteins can be highly conserved in non target species suggesting that similar modes of action (moa) may occur. the aim of this work was to explore whether molecular docking offers a potential tool to predict the effects of pharmaceutical compounds on non target organisms. three highly prescribed drugs, dicl ... | 2013 | 24344392 |
| abundance-occupancy relationships in metapopulations: examples of rock pool daphnia. | intraspecific positive relationships between abundance and occupancy are observed for many species, suggesting that the same processes drive local and regional species dynamics. two main groups of mechanisms explain this relationship: spatiotemporal variation in local population growth rates due to variation in habitat quality, or dispersal effects that increase occupancy of a species when locally abundant. several studies show that spatiotemporal variation in population growth rates causes posi ... | 2011 | 20740290 |
| morphological defenses induced in situ by the invertebrate predator chaoborus: comparison of responses between daphnia pulex and d. rosea. | the presence of plankton predators may induce altered morphology in their potential prey. to date, the mechanism of induction and adaptive value of such defensive responses have been examined in the laboratory. this study investigated the morphological defense structures induced by the invertebrate predator chaoborus in two coexisting daphnia species, d. pulex and d. rosea, in the field. in piscivore lake (gräfenhain, germany), continuous and intense biomanipulation had led to near elimination o ... | 2000 | 28308217 |
| ancient and recent duplications support functional diversity of daphnia opsins. | daphnia pulex has the largest known family of opsins, genes critical for photoreception and vision in animals. this diversity may be functionally redundant, arising from recent processes, or ancient duplications may have been preserved due to distinct functions and independent contributions to fitness. we analyzed opsins in d. pulex and its distant congener daphnia magna. we identified 48 opsins in the d. pulex genome and 32 in d. magna. we inferred the complement of opsins in the last common an ... | 2017 | 28004131 |
| transcriptomic responses in the bloom-forming cyanobacterium microcystis induced during exposure to zooplankton. | the bloom-forming, toxic cyanobacterium microcystis synthesizes multiple secondary metabolites and has been shown to deter zooplankton grazing. however, the biochemical and/or molecular basis by which microcystis deters zooplankton remains unclear. this global transcriptomic study explored the response of microcystis to direct and indirect exposures to multiple densities of two cladoceran grazers, daphnia pulex and d. magna higher densities of both daphnids significantly reduced microcystis cell ... | 2017 | 28003198 |
| comparative developmental staging of female and male water fleas daphnia pulex and daphnia magna during embryogenesis. | the freshwater crustacean genus daphnia has been used extensively in ecological, developmental and ecotoxicological studies. daphnids produce only female offspring by parthenogenesis under favorable conditions, but in response to various unfavorable conditions and external stimuli, they produce male offspring. although we reported that exogenous exposure to juvenile hormones and their analogs can induce male offspring even under female-producing conditions, we recently established a male inducti ... | 2016 | 26853866 |
| small rna sequencing based identification of mirnas in daphnia magna. | small rna molecules are short, non-coding rnas identified for their crucial role in post-transcriptional regulation. a well-studied example includes mirnas (micrornas) which have been identified in several model organisms including the freshwater flea and planktonic crustacean daphnia. a model for epigenetic-based studies with an available genome database, the identification of mirnas and their potential role in regulating daphnia gene expression has only recently garnered interest. computationa ... | 2015 | 26367422 |
| temporal assessment of copper speciation, bioavailability and toxicity in uk freshwaters using chemical equilibrium and biotic ligand models: implications for compliance with copper environmental quality standards. | although significant progress has been made in understanding how environmental factors modify the speciation, bioavailability and toxicity of metals such as copper in aquatic environments, the current methods used to establish water quality standards do not necessarily consider the different geological and geochemical characteristics of a given site and the factors that affect copper fate, bioavailability potential and toxicity. in addition, the temporal variation in the concentration and bioava ... | 2015 | 26318223 |
| cloning, expression and localization of the daphnia carinata transformer gene dcartra during different reproductive stages. | in this study, the full-length cdna of the transformer (tra) gene from the common freshwater species daphnia carinata (dcartra; genbank accession no. kj735445) was cloned using primers based on homologous sequences and rapid amplification of cdna ends (race). the relative expression and localization of dcartra and the cellular abundance of the dcartra protein during different sexual phases were subsequently investigated. the full-length dcartra cdna was 1620 bp with an orf of 1143 bp encoding a ... | 2015 | 25917617 |
| assessing toxicity of copper nanoparticles across five cladoceran species. | as a result of ever increasing applications, nanoparticles will eventually end up in the environment. however, currently no common principle has been established to help understand the toxicity of nanoparticles (nps) across species. therefore, it is difficult to estimate the potential risks of nanoparticles to untested species in the environment. the authors exposed 4 different sizes of copper nanoparticles (cunps) and 1 submicron-sized copper particle to 5 cladoceran species (daphnia magna, dap ... | 2015 | 25826796 |
| multigenerational genomic responses to dietary phosphorus and temperature in daphnia. | temperature and nutrient availability are both hypothesized to affect organisms at the cellular and genomic levels. in this multigenerational study, daphnia magna (d. magna) and daphnia pulex (d. pulex) were maintained at high (20 °c) and low (10 °c) temperatures and nourished with phosphorus (p)-sufficient (50 μmol/l) and p-deficient (2 μmol/l) algae for up to 35 generations to assess the multigenerational impacts on genome size and nucleus size. analysis by flow cytometry revealed significant ... | 2014 | 25389902 |
| living on the edge: populations of two zooplankton species living closer to agricultural fields are more resistant to a common insecticide. | ecological communities across the globe are exposed to diverse natural and anthropogenic stressors and disturbances that can lead to community-wide impacts. contaminants are a group of anthropogenic disturbances that are ubiquitous in the environment and can trigger trophic cascades, increased susceptibility to pathogens, reduced biodiversity, and altered ecosystems. in these ecosystems, substantial attention has been given to evolved resistance in targeted pest species, but little attention has ... | 2014 | 25220688 |
| development and staging of the water flea daphnia magna (straus, 1820; cladocera, daphniidae) based on morphological landmarks. | crustaceans of the genus daphnia are one of the oldest model organisms in ecotoxicology, ecology and evolutionary biology. the publication of the daphnia pulex genome has facilitated the development of genetic tools to answer long-standing questions in these research fields (science 331: 555-561, 2011). a particular focus is laid on understanding the genetic basis of the striking ability of daphnids to change their phenotype in response to environmental stressors. furthermore, daphnia have recen ... | 2014 | 24641948 |
| larger daphnia at lower temperature: a role for cell size and genome configuration? | experiments with daphnia magna and daphnia pulex raised at 10 and 20 °c yielded larger adult size at the lower temperature. this must reflect increased cell size, increased cell numbers, or a combination of both. as it is difficult to achieve good estimates on cell size in crustaceans, we, therefore, measured nucleus and genome size using flow cytometry at 10 and 20 °c. dna was stained with propidium iodide, ethidium bromide, and dapi. both nucleus and genome size estimates were elevated at 10 ° ... | 2013 | 24168672 |
| transcription patterns of genes encoding four metallothionein homologs in daphnia pulex exposed to copper and cadmium are time- and homolog-dependent. | metallothioneins are proteins that play an essential role in metal homeostasis and detoxification in nearly all organisms studied to date. yet discrepancies between outcomes of chronic and acute exposure experiments hamper the understanding of the regulatory mechanisms of their isoforms following metal exposure. here, we investigated transcriptional differences among four identified homologs (mt1-mt4) in daphnia pulex exposed across time to copper and cadmium relative to a control. transcription ... | 2013 | 24113165 |
| interspecific differences between d. pulex and d. magna in tolerance to cyanobacteria with protease inhibitors. | it is known that cyanobacteria negatively affect herbivores due to their production of toxins such as protease inhibitors. in the present study we investigated potential interspecific differences between two major herbivores, daphnia magna and daphnia pulex, in terms of their tolerance to cyanobacteria with protease inhibitors. seven clones each of d. magna and of d. pulex were isolated from different habitats in europe and north america. to test for interspecific differences in the daphnids' to ... | 2013 | 23650523 |
| how to measure maturation: a comparison of probabilistic methods used to test for genotypic variation and plasticity in the decision to mature. | maturation is a developmental trait that plays a key role in shaping organisms' life-history. however, progress in understanding how maturation phenotypes evolve has been held back by confusion over how best to model maturation decisions and a lack of studies comparing genotypic variation in maturation. here, we fitted probabilistic maturation reaction norms (pmrns) to data collected from five clones of daphnia magna and five of daphnia pulex collected from within and between different populatio ... | 2013 | 23356623 |
| from genes to behavior: investigations of neurochemical signaling come of age for the model crustacean daphnia pulex. | the cladoceran crustacean daphnia pulex has served as a standard organism for aquatic toxicity testing for decades. the model organism status of d. pulex rests largely on its remarkable ability to rapidly adapt morphologically, physiologically and behaviorally to a wide range of environmental challenges, as well as on its parthenogenetic reproduction and ease of laboratory culture. as in all multicellular organisms, neurochemical control systems are undoubtedly major contributors to the function ... | 2012 | 22786629 |
| electroantennogram measurement of the olfactory response of daphnia spp. and its impairment by waterborne copper. | in this study an electroantennogram (eag) method was developed for use on live daphniids. the eag response of daphnia magna and daphnia pulex to a variety of amino acids was measured. the strongest response measured was elicited by l-arginine and was shown to induce a concentration-dependent response indicating the response is olfactory in nature. subsequent exposures of d. magna to a low, ecologically-relevant concentration of copper (7.5 μg/l) showed a disruption in eag function. this study ut ... | 2012 | 22721843 |
| neurogenesis in the water flea daphnia magna (crustacea, branchiopoda) suggests different mechanisms of neuroblast formation in insects and crustaceans. | within euarthropods, the morphological and molecular mechanisms of early nervous system development have been analysed in insects and several representatives of chelicerates and myriapods, while data on crustaceans are fragmentary. neural stem cells (neuroblasts) generate the nervous system in insects and in higher crustaceans (malacostracans); in the remaining euarthropod groups, the chelicerates (e.g. spiders) and myriapods (e.g. millipedes), neuroblasts are missing. in the latter taxa, groups ... | 2011 | 21624360 |
| frequency and inheritance of non-male producing clones in daphnia magna: evolution towards sex specialization in a cyclical parthenogen? | in daphnia (cladocera, crustacea), parthenogenetic reproduction alternates with sexual reproduction. individuals of both sexes that belong to the same parthenogenetic line are genetically identical, and their sex is determined by the environment. previously, non-male producing (nmp) genotypes have been described in species of the daphnia pulex group. such genotypes can only persist through phases of sexual reproduction if they co-occur with normal (mp) genotypes that produce both males and femal ... | 2011 | 21599772 |
| histaminergic signaling in the central nervous system of daphnia and a role for it in the control of phototactic behavior. | daphnia magna and daphnia pulex are well-established model organisms in the fields of ecotoxicology and toxicogenomics. among the many assays used for determining the effects of environmental and anthropogenic stressors on these animals is monitoring for changes in their phototactic behavior. in most arthropods, histamine has been shown to play a key role in the visual system. currently, nothing is known about histaminergic signaling in either d. magna or d. pulex. here, a combination of immunoh ... | 2011 | 21525325 |
| trehalose and vitreous states: desiccation tolerance of dormant stages of the crustaceans triops and daphnia. | several aquatic organisms are able to withstand extreme desiccation in at least one of their life stages. this is commonly known as "anhydrobiosis." it was often thought that to tolerate such a desiccated state required high amounts of compatible solutes such as the nonreducing disaccharide trehalose, which protects cellular structures by water replacement and glass formation. trehalose levels of dormant eggs and cysts of five freshwater crustaceans (daphnia magna, daphnia pulex, triops longicau ... | 2013 | 21460525 |
| pigment-dispersing hormone in daphnia interneurons, one type homologous to insect clock neurons displaying circadian rhythmicity. | we report identification of a beta-type pigment-dispersing hormone (pdh) identical in two water flea species, daphnia magna and daphnia pulex. it has been identified by cloning of precursors, chromatographic isolation from tissue extracts followed by immunoassays and de novo-mass spectrometric sequencing. the peptide is restricted to a complex system of distinct interneurons in the brain and visual ganglia, but does not occur in neurosecretory cells projecting to neurohemal organs as in decapod ... | 2011 | 21365282 |
| can site-specific heuristic toxicity models predict the toxicity of produced water? | an empirically derived model of major ion toxicity was combined with other toxicity assessments to account for the observed toxicity in field-collected produced water and produced water contaminated groundwater. the accuracy and precision of the ion toxicity model, calculated using model deviation ratios (mdr) and simple linear regressions, was determined for fathead minnows, ceriodaphnia dubia, and daphnia magna. model accuracy for produced water fell within a factor of two for all three organi ... | 2010 | 20466406 |
| acute toxicity and hazard assessment of spinosad and r-11 to three cladoceran species and coho salmon. | acute toxicity data and hazard assessments were developed for three cladoceran species, ceriodaphnia dubia, daphnia pulex, and daphnia magna, and juvenile coho salmon, oncorhynchus kisutch after exposure to the insecticide, spinosad and adjuvant r-11. the effect of a mixture of these compounds was also determined with c. dubia and o. kisutch. spinosad was virtually non-toxic to o. kisutch. hazard assessments indicated that r-11 posed no hazard to any of the species tested while spinosad only pos ... | 2009 | 19159051 |
| the effect of water chemistry on the acute toxicity of nickel to the cladoceran daphnia pulex and the development of a biotic ligand model. | the goal of this study was to evaluate the influence of water chemistry parameters on the acute toxicity of waterborne ni to daphnia pulex in soft waters and using this information to develop a biotic ligand model. the effects of ca, mg, na, k, cl, ph (two differently buffered sets) and natural organic matter (nom) from two sources were evaluated in standardized 48h acute toxicity tests. increases in ca2+ had a protective effect on ni toxicity, suggesting that this ion competes with ni at the si ... | 2009 | 19111357 |
| comparative toxicity of cadmium, zinc, and mixtures of cadmium and zinc to daphnids. | investigations were conducted to determine acute (48-h) effects of cadmium and zinc presented individually and in combination on ceriodaphnia dubia, daphnia magna, daphnia ambigua, and daphnia pulex. toxicity tests were conducted with single metals to determine lethal effects concentrations (lethal concentrations predicted for a given percent [x] of a population, lcx value). these were used to derive metal combinations that spanned a range of effects and included mixtures of lc15, lc50, and lc85 ... | 2006 | 16494240 |
| biotic ligand model prediction of copper toxicity to daphnids in a range of natural waters in chile. | the objective of this study was to assess the predictive capacity of the biotic ligand model (blm) for acute copper toxicity to daphnids as applied to a number of freshwaters from chile and to synthetic laboratory-prepared waters. thirty-seven freshwater bodies were sampled, chemically characterized, and used to determine the copper concentration associated with the 50% of mortality (lc50) for daphnia magna, daphnia pulex, and daphnia obtusa (native to chile). the data were then used to run thre ... | 2005 | 16111013 |
| unhairing effluents treated by an activated sludge system. | leather tannery effluents are a source of severe environmental impacts. in particular, the unhairing stage, belonging to beamhouse processes, generates a significantly toxic, alkaline wastewater with high concentrations of organic matter, sulphides, suspended solids and salts. the objective of this work was to evaluate the biodegradability and toxicity of diluted unhairing wastewater after being treated by an activated sludge (as) system. the biomass activity of the as was also evaluated. the as ... | 2004 | 15225940 |
| tannery wastewater characterization and toxicity effects on daphnia spp. | tannery wastewater contains large quantities of organic and inorganic compounds, including toxic substances such as sulfides and chromium salts. the evaluation of wastewater quality in chile nowadays is based on chemical specific measurements and toxicity tests. the goal of this research was to characterize tannery wastewater and to relate its physical/chemical parameters with its acute toxicity effect on daphnia pulex. to distinguish the most important toxic compounds, physical/chemical techniq ... | 2003 | 12539143 |
| derivation of a toxicity-based model to predict how water chemistry influences silver toxicity to invertebrates. | the effect of altering water chemistry on acute silver toxicity to three invertebrate species, two daphnids, daphnia magna and daphnia pulex, as well as an amphipod gammarus pulex was assessed. in addition, the physiological basis of ag(i) toxicity to g. pulex was examined. daphnia magna and d. pulex were more sensitive than g. pulex and 48 h lc(50) values in synthetic ion poor water were 0.47, 0.65 and 2.1 microg ag(i) l(-1), respectively. increasing water [cl(-)] reduced ag(i) toxicity in all ... | 2002 | 12356532 |
| the acute toxicity of selected alkylphenols to young and adult daphnia magna. | differences in sensitivity toward toxicants between young and adult individuals in a population are assumed to be primarily associated with their difference in body size. this assumption plays a key role in the modeling of effects of variable concentrations of toxicants on nonhomogeneous populations. the hazard-based no-effect-concentrations (necs), killing rates, and elimination rates, estimated from the survival data of a series of acute toxicity tests with young and adults of daphnia magna an ... | 1998 | 9570914 |
| investigating the potential impacts of chlorophenols on the lake baikal (siberia, russia) food web by employing daphnia grazing bioassays and a chlorella growth bioassay | a grazing bioassay was employed to assess the impacts of chlorophenols on daphnia magna and daphnia pulex. the effects of two chlorophenols, pentachlorophenol (pcp) and 4-chlorophenol, were investigated at concentrations of 0.001, 0.01, and 0.1 mg . l-1 over a 96-h period. all tests were conducted in water from the southern basin of lake baikal (siberia). for d. magna, grazing rates were significantly depressed after exposure to 0.001 mg . l-1 of pcp for 48 h or to 0.01 mg . l-1 of 4-chloropheno ... | 1998 | 9504970 |
| grazing resistance in nutrient-stressed phytoplankton. | grazing experiments were performed with the zooplankters daphnia pulex and daphnia magna, feeding on phosphorus-saturated and phosphorus-limited cells of two green algae (scenedesmus subspicatus and selenastrum capricornutum). p-limited algal cells passed largely intact through the gut and were thus spared from heavy grazing pressure. p-saturated algal cells, in contrast, were efficiently assimilated. structural and morphological changes in the p-limited cells most probably reduced their digesti ... | 1993 | 28313818 |
| piperonyl butoxide as a tool in aquatic toxicological research with organophosphate insecticides. | experiments were conducted to determine the effects of piperonyl butoxide, a synthetic methylenedioxyphenyl inhibitor of cytochrome(s) p450, on the toxicity of organophosphate insecticides to three cladoceran test species: ceriodaphnia dubia. daphnia magna, and daphnia pulex. coadministration of piperonyl butoxide effectively reduced the acute toxicity of four metabolically activated organophosphates (parathion, methyl parathion, diazinon, and malathion) and did not affect the toxicity of three ... | 1991 | 1868783 |
| acute toxicity of triphenyltin hydroxide to three cladoceran species. | the toxicity of an organotin pesticide, triphenyltin hydroxide, was assessed with several freshwater cladoceran species. daphnia pulex, daphnia magna, and ceriodaphnia dubia were exposed for 48 h to triphenyltin hydroxide in static acute toxicity tests. values of the 48-h trimmed spearman-karber ec(50)s for the three species were found to be 14.5, 16.5, and 11.3 microg litre(-1), respectively. analysis of variance performed on ec(50) values of replicates revealed no significant differences betwe ... | 1989 | 15092487 |
| effect of selenium deficiency on cuticle integrity in the cladocera (crustacea). | daphnia pulex de geer and daphnia magna straus populations cannot be maintained in defined (sensu stricto) media containing less than 0.1 part per billion (ppb) of selenium. a concentration of 1 ppb is sufficient to satisfy minimal needs in otherwise sufficient media. in the first generation with no selenium added to the medium or detected in it, media deficiency is shown by a premature cuticle deterioration visually similar to senescence, by progressive loss of distal segments of second antenna ... | 1984 | 6587360 |
| acute toxicity studies of surfactants to daphnia magna and daphnia pulex. | | 1979 | 231941 |
| seasonal patterns of total and energy reserve lipids of dominant zooplanktonic crustaceans from a hyper-eutrophic lake. | seasonal patterns of lipid reserves and lipid classes of dominant zooplankton in a hyper-eutrophic lake were examined in relation to algal food resources. triacylglycerol was the principle lipid energy reserve in all five species examined. during the height of the yearlyaphanizomenon flos-aquae bloom, lipid levels of the principle herbivores (daphnia pulex andleptodiaptomus sicilis) and an omnivore (diacyclops bicuspidatus thomasi), were at their lowest concentration, suggesting that this cyanob ... | 1992 | 28313577 |
| population genomics of daphnia pulex. | using data from 83 isolates from a single population, the population genomics of the microcrustacean daphnia pulex are described and compared to current knowledge for the only other well-studied invertebrate, drosophila melanogaster these two species are quite similar with respect to effective population sizes and mutation rates, although some features of recombination appear to be different, with linkage disequilibrium being elevated at short (< 100 bp) distances in d. melanogaster and at long ... | 2016 | 27932545 |
| identification of putative circadian clock genes in the american horseshoe crab, limulus polyphemus. | while the american horseshoe crab, limulus polyphemus, has robust circadian and circatidal rhythms, virtually nothing is known about the molecular basis of these rhythms in this species or any other chelicerate. in this study, next generation sequencing was used to assemble transcriptomic reads and then putative homologs of known core and accessory circadian genes were identified in these databases. homologous transcripts were discovered for one circadian clock input gene, five core genes, 22 ac ... | 2016 | 27341138 |
| evolution of neuropeptides in non-pterygote hexapods. | neuropeptides are key players in information transfer and act as important regulators of development, growth, metabolism, and reproduction within multi-cellular animal organisms (metazoa). these short protein-like substances show a high degree of structural variability and are recognized as the most diverse group of messenger molecules. we used transcriptome sequences from the 1kite (1k insect transcriptome evolution) project to search for neuropeptide coding sequences in 24 species from the non ... | 2016 | 26923142 |
| identification of hox genes and rearrangements within the single homeobox (hox) cluster (192.8 kb) of the cyclopoid copepod (paracyclopina nana). | we report the first identification of the entire complement of the eight typical homeobox (hox) genes (lab, pb, dfd, scr, antp, ubx, abd-a, and abd-b) and the ftz gene in a 192.8 kb region in the cyclopoid copepod paracyclopina nana. a hox3 gene ortholog was not present in the p. nana hox gene cluster, while the p. nana dfd gene was transcribed in the opposite direction to the daphnia pulex dfd gene, but in the same direction as the dfd genes of the fruit fly drosophila melanogaster and red flou ... | 2016 | 26833546 |
| microsatellite evolutionary rate and pattern in schistocerca gregaria inferred from direct observation of germline mutations. | unravelling variation among taxonomic orders regarding the rate of evolution in microsatellites is crucial for evolutionary biology and population genetics research. the mean mutation rate of microsatellites tends to be lower in arthropods than in vertebrates, but data are scarce and mostly concern accumulation of mutations in model species. based on parent-offspring segregations and a hierarchical bayesian model, the mean rate of mutation in the orthopteran insect schistocerca gregaria was esti ... | 2015 | 26562076 |
| characterization of microsatellite loci and repeat density in the gooseneck barnacle, pollicipes elegans, using next generation sequencing. | pollicipes elegans is a commercially important and biogeographically significant rocky-shore gooseneck barnacle found along the eastern pacific coasts of peru, el salvador, and mexico. little is known about its reproductive biology, and no genetic resources exist despite its growing importance as a fisheries species in the region. next generation sequencing methods can provide rapid and cost-effective development of molecular markers such as microsatellites, which can be applied to studies of pa ... | 2013 | 24115106 |
| a gene-based snp linkage map for pacific white shrimp, litopenaeus vannamei. | pacific white shrimp (litopenaeus vannamei) are of particular economic importance to the global shrimp aquaculture industry. however, limited genomics information is available for the penaeid species. we utilized the limited public information available, mainly single nucleotide polymorphisms (snps) and expressed sequence tags, to discover markers for the construction of the first snp genetic map for pacific white shrimp. in total, 1344 putative snps were discovered, and out of 825 snps genotype ... | 2010 | 19968647 |
| mgescan-non-ltr: computational identification and classification of autonomous non-ltr retrotransposons in eukaryotic genomes. | computational methods for genome-wide identification of mobile genetic elements (mges) have become increasingly necessary for both genome annotation and evolutionary studies. non-long terminal repeat (non-ltr) retrotransposons are a class of mges that have been found in most eukaryotic genomes, sometimes in extremely high numbers. in this article, we present a computational tool, mgescan-non-ltr, for the identification of non-ltr retrotransposons in genomic sequences, following a computational a ... | 2009 | 19762481 |
| lc-ms/ms-based proteome profiling in daphnia pulex and daphnia longicephala: the daphnia pulex genome database as a key for high throughput proteomics in daphnia. | daphniids, commonly known as waterfleas, serve as important model systems for ecology, evolution and the environmental sciences. the sequencing and annotation of the daphnia pulex genome both open future avenues of research on this model organism. as proteomics is not only essential to our understanding of cell function, and is also a powerful validation tool for predicted genes in genome annotation projects, a first proteomic dataset is presented in this article. | 2009 | 19383153 |
| cuticle differentiation in the embryo of the amphipod crustacean parhyale hawaiensis. | the arthropod cuticle is a multilayered extracellular matrix produced by the epidermis during embryogenesis and moulting. molecularly and histologically, cuticle differentiation has been extensively investigated in the embryo of the insect drosophila melanogaster. to learn about the evolution of cuticle differentiation, we have studied the histology of cuticle differentiation during embryogenesis of the amphipod crustacean parhyale hawaiensis, which had a common ancestor with drosophila about 51 ... | 2008 | 18293012 |
| evolution of hox3 and ftz in arthropods: insights from the crustacean daphnia pulex. | the drosophila melanogaster genes zerknüllt (zen) and fushi tarazu (ftz) are members of the hox gene family whose roles have changed significantly in the insect lineage and thus provide an opportunity to study the mechanisms underlying the functional evolution of hox proteins. we have studied the expression of orthologs of zen (dpuhox3) and ftz (dpuftz) in the crustacean daphnia pulex (branchiopoda), both of which show a dynamic expression pattern. dpuhox3 is expressed in a complex pattern in ea ... | 2007 | 17310351 |
| toxicity and hazard assessment of fipronil to daphnia pulex. | hazard assessments based on two measures of toxicity were conducted for the water flea, daphnia pulex (leydig) exposed to the insecticide, fipronil. the measures of toxicity obtained were 48 h acute lethal concentration estimates, and a direct measure of population growth rate, the 10-day instantaneous rate of increase (r(i)). additionally, life tables were developed after exposure to several concentrations to tease out the apparent sublethal effects of this insecticide to d. pulex. the acute lc ... | 2005 | 15978286 |
| partial mitochondrial dna sequence of the crustacean daphnia pulex. | a 3667-base pair (bp) fragment of the mitochondrial genome of the crustacean daphnia pulex has been sequenced and found to contain the complete genes for the small subunit ribosomal rna, nd2, seven trnas and the control region. this organization is identical to that found in drosophila yakuba mtdna yet d. pulex mtdna exhibits several unique features when compared to other mitochondrial sequences. the sequenced fragment is only 62.6% a + t which is much lower than that of any other arthropod mtdn ... | 1994 | 8082168 |
| evaluating the trophic transfer of cadmium, polonium, and methylmercury in an estuarine food chain. | we examined the transfer of cd, methylmercury (mehg), and po in an estuarine food chain (from phytoplankton to zooplankton [daphnia pulex] to killifish [fundulus heteroclitus] and, finally, to juvenile striped bass [morone saxatilis]) to better understand both the extent to which these elements may biomagnify and the underlying mechanisms governing this biomagnification. among the phytoplankton examined (cyclotella meneghiniana and chlamdomonas reinhardtii), metal uptake was rapid, and volume co ... | 2008 | 18419184 |
| data for comparative proteomics of ovaries from five non-model, crustacean amphipods. | ovaries were taken from five sexually mature amphipods: gammarus fossarum, gammarus pulex, gammarus roeseli, hyallela azteca and parhyale hawaiensis. the soluble proteome extracted from individual pair of ovaries from five biological replicates was trypsin digested and the resulting peptides were analyzed by high resolution tandem mass spectrometry. the spectra were assigned with four protein sequence databases with different specificities: a rnaseq-derived g. fossarum database; a rnaseq-derived ... | 2015 | 26380837 |
| interaction between stress induced by competition, predation, and an insecticide on the response of aquatic invertebrates. | the present study investigated the effects of species interactions like competition and (intraguild) predation on the sensitivity of aquatic organisms to the insecticide chlorpyrifos. in the first experiment, combined effects of chlorpyrifos and different levels of intraspecific and interspecific interaction were assessed on gammarus pulex survival using asellus aquaticus as an interacting species. intraspecific and interspecific interactions increased the time to extinction of g. pulex up to a ... | 2017 | 28295548 |
| the alignment between phenotypic plasticity, the major axis of genetic variation and the response to selection. | phenotypic plasticity is the ability of a genotype to produce more than one phenotype in order to match the environment. recent theory proposes that the major axis of genetic variation in a phenotypically plastic population can align with the direction of selection. therefore, theory predicts that plasticity directly aids adaptation by increasing genetic variation in the direction favoured by selection and reflected in plasticity. we evaluated this theory in the freshwater crustacean daphnia pul ... | 2015 | 26423845 |
| chaoborus and gasterosteus anti-predator responses in daphnia pulex are mediated by independent cholinergic and gabaergic neuronal signals. | many prey species evolved inducible defense strategies that protect effectively against predation threats. especially the crustacean daphnia emerged as a model system for studying the ecology and evolution of inducible defenses. daphnia pulex e.g. shows different phenotypic adaptations against vertebrate and invertebrate predators. in response to the invertebrate phantom midge larvae chaoborus (diptera) d. pulex develops defensive morphological defenses (neckteeth). cues originating from predato ... | 2012 | 22590631 |
| about the interest of a zooplankton compartment in pond systems: methodology to study the growth kinetic of daphnia pulex on scenedesmus sp. | a reliable characterization of cladocerans' growth kinetic on their substrates is crucial for the estimation of their biochemical conversion rate in pond models. although many studies reported cladocerans' growth inhibitions by high chlorophyceae contents, their growth kinetics had continued to be described in many pond system models by monod-type kinetic, which describes growth saturation by high substrate contents, but fails to explain the disappearance of cladocerans observed during chlorophy ... | 2015 | 26442483 |
| combined exposure to cyanobacteria and carbaryl results in antagonistic effects on the reproduction of daphnia pulex. | in aquatic ecosystems, daphnia are exposed to a wide variety of natural and chemical stressors that can cause interactive effects resulting in an increased impact on aquatic ecosystems. the authors therefore investigated the interactive effects of harmful cyanobacteria (cyanohabs) with carbaryl in daphnia pulex, because cyanobacteria have become an important concern for aquatic ecosystems. daphnia were exposed for 21 d to 4 selected cyanobacteria (aphanizomenon sp., cylindrospermopsis raciborski ... | 2013 | 23733205 |
| a survey of well conserved families of c2h2 zinc-finger genes in daphnia. | a recent comparative genomic analysis tentatively identified roughly 40 orthologous groups of c2h2 zinc-finger proteins that are well conserved in "bilaterians" (i.e. worms, flies, and humans). here we extend that analysis to include a second arthropod genome from the crustacean, daphnia pulex. | 2010 | 20433734 |
| rapid toxicity assessment using an in vivo enzyme test for brachionus plicatilis (rotifera). | a 1-hr in vivo enzyme inhibition assay based on esterase activity has good potential for marine toxicity assessment. a test was developed for the rotifer brachionus plicatilis based on the nonfluorescent substrate fluorescein diacetate (fda), which is metabolized by esterases to a fluorescent product. enzyme inhibition, as determined by reduced fluorescence, can be scored visually or quantified using a fluorometer. quantification of fluorescence permits the calculation of noec, loec, chronic val ... | 1995 | 7540536 |
| if you see one, have you seen them all?: community-wide effects of insecticide cross-resistance in zooplankton populations near and far from agriculture. | the worldwide use of pesticides has led to increases in agricultural yields by reducing crop losses. however, increased pesticide use has resulted in pesticide-resistant pest species and recent studies have discovered pesticide-resistance in non-target species living close to farms. such increased tolerance not only affects the species, but can alter the entire food web. given that some species can evolve not only resistance to a single pesticide, but also cross-resistance to other pesticides th ... | 2016 | 27208756 |
| wetland defense: naturally occurring pesticide resistance in zooplankton populations protects the stability of aquatic communities. | anthropogenic stressors are ubiquitous and have been implicated in worldwide declines of terrestrial and aquatic species. pesticides are one such stressor that can have profound effects on aquatic communities by directly affecting sensitive species and indirectly affecting other species via trophic cascades, which can alter ecosystem function. however, there is growing evidence that non-target species can evolve increased resistance. when such species are important drivers of the food web, then ... | 2016 | 26875187 |
| elaphoidella grandidieri (harpacticoida: copepoda): demographic characteristics and possible use as live prey in aquaculture. | in freshwater ecosystems, rotifers and cladocerans are ideal prey for fish larvae whereas copepods, due to their purported low growth rate and predatory tendency, are not. we recently isolated the parthenogenetic elaphoidella grandidieri (gueme et richard, 1893) a benthic freshwater harpacticoid, from a fish farm in the state of morelos, central mexico and tested its potential as a live prey organism for larval vertebrates. population growth and life table demography experiments were conducted, ... | 2011 | 22315830 |
| decolorization of different textile dyes by penicillium simplicissimum and toxicity evaluation after fungal treatment. | the objective of this study was to investigate the capacity of decolorization and detoxification of the textile dyes reactive red 198 (rr198), reactive blue 214 (rb214), reactive blue 21 (rb21) and the mixture of the three dyes (mxd) by penicillium simplicissimum incqs 40211. the dye rb21, a phthalocyanine, was totally decolorized in 2 days, and the others, the monoazo rr198, the diazo rb214 and mxd were decolorized after 7 days by p. simplicissimum. initially the dye decolorization involved dye ... | 2009 | 24031428 |
| new insights into the distribution of polyploid daphnia: the holarctic revisited and argentina explored. | it has long been known that polyploid organisms are more prevalent in arctic than in temperate environments. past explanations for this geographical trend have focused on the role of glacial cycles in generating polyploids and the influence of abiotic factors in favouring polyploidy in the north. in combination, these mechanisms probably suffice to explain the observed geographical cline in ploidy levels in members of the daphnia pulex complex in the holarctic. while only diploid members of the ... | 2002 | 12074728 |
| toxicity assessment of a complex industrial wastewater using aquatic and terrestrial bioassays daphnia pulex and lactuca sativa. | aquatic and terrestrial bioassays were used to assess toxicity at several stages in an industrial wastewater treatment plant that processes 400 l/s from a complex influent formed by wastewater from 135 industries. daphnia pulex and lactuca sativa were used to assess and compare toxicity between the influent wastewater and effluent wastewater from an activated sludge process, and compare their relationship with physicochemical parameters of biological oxygen demand (bod); chemical oxygen demand ( ... | 2007 | 17680481 |
| interaction of the red pigment-concentrating hormone of the crustacean daphnia pulex, with its cognate receptor, dappu-rpchr: a nuclear magnetic resonance and modeling study. | the primary sequence of the red pigment-concentrating hormone (rpch) receptor of the water flea, daphnia pulex, was used in homology modeling to construct the first 3d model of a crustacean g-protein coupled receptor, dappu-rpchr. this receptor was found to belong to the class a subfamily of gpcrs with a disulfide bridge between cys72 and cys150 and an ionic lock between arg97 and thr224 and thr220. nmr restrained molecular dynamics was used to determine the structure of an agonist, dappu-rpch, ... | 2018 | 28837848 |
| predators modify the evolutionary response of prey to temperature change. | as climate regimes shift in many ecosystems worldwide, evolution may be a critical process allowing persistence in rapidly changing environments. organisms regularly interact with other species, yet whether climate-mediated evolution can occur in the context of species interactions is not well understood. we tested whether a species interaction could modify evolutionary responses to temperature. we demonstrate that predation pressure by dipteran larvae (chaoborus americanus) modified the evoluti ... | 2015 | 26673935 |
| changes in water chemistry can disable plankton prey defenses. | the effectiveness of antipredator defenses is greatly influenced by the environment in which an organism lives. in aquatic ecosystems, the chemical composition of the water itself may play an important role in the outcome of predator-prey interactions by altering the ability of prey to detect predators or to implement defensive responses once the predator's presence is perceived. here, we demonstrate that low calcium concentrations (<1.5 mg/l) that are found in many softwater lakes and ponds dis ... | 2012 | 22949653 |
| morphological responses of daphnia pulex to chaoborus americanus kairomone in the presence and absence of metals. | daphnia pulex neonates develop neck teeth in the presence of predatory kairomone from chaoborus americanus that are fed d. pulex. these neck teeth reduce the susceptibility of the neonates to predation. evidence suggests that aqueous metals interfere with chemical communication in fish. the objective of our study was to determine if cu or ni at environmentally relevant concentrations affects predatory kairomone response in d. pulex. to test this possibility, d. pulex were placed in increasing wa ... | 2004 | 15180385 |
| the genetics of phenotypic plasticity. viii. the cost of plasticity in daphnia pulex. | in a heterogeneous world, the optimal strategy for an individual is to continually change its phenotype to match the optimal type. however, in the real world, organisms do not behave in this fashion. one potential reason why is that phenotypic plasticity is costly. we measured production and maintenance costs of plasticity in the freshwater crustacean daphnia pulex (cladocera: crustacea) in response to the presence of chemical signals from a predator, the insect chaoborus americanus. we looked a ... | 1998 | 28568340 |
| phenotypic plasticity of daphnia pulex in the presence of invertebrate predators: morphological and life history responses. | morphological and life history traits of two clones of the cladoceran daphnia pulex were measured in the presence and absence of size-selective insect predators, the midge larva chaoborus flavicans, which preys on small daphnia, and the water bug notonecta glauca, which preys on large daphnia. the aim was to detect predator-induced phenotypic changes, particularly the effect of simultaneous exposure to both types of predators. other work has shown that in the presence of chaoborus americanus, da ... | 1992 | 28312604 |
| the evolutionary ecology of an antipredator reaction norm: daphnia pulex and chaoborus americanus. | ponds containing the parthenogenetic zooplankter daphnia pulex with and without chaoborid predators were sampled over the course of a season. a significant (p < 0.05) spearman rank correlation was found between predator density and the expression of an antipredator defense (neckteeth) by the daphnia. the reaction norms (percent induction of a single genotype versus predator density) of clones isolated from predator-free and predator-rich habitats were determined in a laboratory setting. there wa ... | 1991 | 28564128 |
| chaoborus predation and life-history evolution in daphnia pulex: temporal pattern of population diversity, fitness, and mean life history. | the effect of predation by the aquatic dipteran larva chaoborus americanus on genetic diversity and life-history evolution in the cladoceran daphnia pulex was investigated in large replicate laboratory populations. instantaneous daily loss rates of clonal diversity and genetic variance for fitness indicate that 93-99% of initial genetic diversity can be removed from populations during the 8-12 generations of clonal reproduction that occur each year in natural populations. in the absence of preda ... | 1991 | 28564082 |
| demographic costs of chaoborus-induced phenotypic plasticity in daphnia pulex. | it has been proposed that morphological defenses against predation have demographic costs. we measured the cost of a predator-induced morphological defense, using predaceous phantom midge larvae chaoborus americanus (insecta, diptera) and the prey species daphnia pulex (crustacea, cladocera). the induced defense is a neck tooth (and other pleiotropic structures) developed in juvenile d. pulex in the presence of c. americanus. laboratory life table experiments, in the absence of predation, indica ... | 1990 | 28313251 |
| chaoborus americanus predation on various zooplankters; functional response and behavioral observations. | predation rates for chaoborus americanus on different types of noncyclomorphic zooplankton prey were determined in the laboratory as a function of both prey species and density. the sequence of events leading to consumption of prey was also observed, and probabilities determined for the various components.predation rates generally reached an upper limit as the density of prey increased to high levels. larger prey were always less vulnerable to chaoborus predation. among the species of zooplankto ... | 1980 | 28310942 |
| chaoborus crystallinus predation on daphnia pulex: can induced morphological changes balance effects of body size on vulnerability? | juvenile daphnia pulex form neckteeth in reponse to chemicals released by predatory chaoborus crystallinus larvae. formation of neckteeth is strongest in the second instar followed by the third instar, whereas only small neckteeth are found in the first and fourth instar of experimental clones. predation experiments showed that body-size-dependent vulnerability of animals without neckteeth to fourth instar c. crystallinus larvae matched the pattern of neckteeth formation over the four juvenile i ... | 1995 | 28306785 |
| interactive effects of xenobiotic, abiotic and biotic stressors on daphnia pulex--results from a multiple stressor experiment with a fractional multifactorial design. | pollutant effects on aquatic key species are confounded by multiple abiotic and biotic stressors. to better discriminate and understand the intrinsic and environmental correlates of changing aquatic ecosystems, we untangle in present study how the effects of a low-dosed fungicide on daphnids (via different exposure routes) becomes modified by increasing temperature and the presence of a predator. using a fractional multifactorial test design, the individual growth, reproduction and population gr ... | 2013 | 23727598 |
| reciprocity in predator-prey interactions: exposure to defended prey and predation risk affects intermediate predator life history and morphology. | a vast body of literature exists documenting the morphological, behavioural and life history changes that predators induce in prey. however, little attention has been paid to how these induced changes feed back and affect the predators' life history and morphology. larvae of the phantom midge chaoborus flavicans are intermediate predators in a food web with daphnia pulex as the basal resource and planktivorous fish as the top predator. c. flavicans prey on d. pulex and are themselves prey for fi ... | 2010 | 19936795 |
| density-dependent effects of prey defences. | in this study, we show that the protective advantage of a defence depends on prey density. for our investigations, we used the predator-prey model system chaoborus-daphnia pulex. the prey, d. pulex, forms neckteeth as an inducible defence against chaoborid predators. this morphological response effectively reduces predator attack efficiency, i.e. number of successful attacks divided by total number of attacks. we found that neckteeth-defended prey suffered a distinctly lower predation rate (prey ... | 2000 | 28308594 |
| comparative effects of sediment versus aqueous polychlorinated biphenyl (pcb) exposure on benthic and planktonic invertebrates. | polychlorinated biphenyls (pcbs) are an environmental concern because of their adverse effects on humans and wildlife, and understanding the contribution of various matrices (i.e., sediment and water) to pcb exposure on aquatic communities is critical for successful remediation of impacted sites. the present study examined the toxicity of different routes of pcb exposure in aquatic invertebrates. in complementary laboratory and field experiments, the authors compared the effects of aqueous versu ... | 2014 | 24464368 |
| acute toxicity, critical body residues, michaelis-menten analysis of bioaccumulation, and ionoregulatory disturbance in response to waterborne nickel in four invertebrates: chironomus riparius, lymnaea stagnalis, lumbriculus variegatus and daphnia pulex. | we investigated the bioaccumulation and acute toxicity (48 h or 96 h) of ni in four freshwater invertebrate species in two waters with hardness of 40 (soft water) and 140 mg l(-1) as caco(3) (hard water). sensitivity order (most to least) was lymnaea stagnalis > daphnia pulex > lumbriculus variegatus > chironomus riparius. in all cases water hardness was protective against acute ni toxicity with lc(50) values 3-3.5× higher in the hard water vs. soft water. in addition, higher water hardness sign ... | 2013 | 23570754 |
| toxicity to freshwater organisms from oils and oil spill chemical treatments in laboratory microcosms. | toxicity and temporal changes in toxicity of freshwater-marsh-microcosms containing south louisiana crude (slc) or diesel fuel and treated with a cleaner or dispersant, were investigated using chironomus tentans, daphnia pulex, and oryzias latipes. bioassays used microcosm water (for d. pulex and o. latipes) or soil slurry (for c. tentans) taken 1,7, 31, and 186 days after treatment. slc was less toxic than diesel, chemical additives enhanced oil toxicity, the dispersant was more toxic than the ... | 2003 | 12531308 |
| chronic effects of the herbicide diuron on freshwater cladocerans, amphipods, midges, minnows, worms, and snails. | the chronic effects of the herbicide diuron on survival and reproduction of daphnia pulex, and survival and growth of the amphipod hyalella azteca, the midge chironomus tentans, juvenile and embryo/larval fathead minnows, pimephales promelas, annelid worms, lumbriculus variegatus, and snails, physa gyrina, were determined in laboratory static and static-renewal tests. d. pulex 96-h and 7-day lc50 values were 17.9 and 7.1 mg/l; 7-day loael and noael values based on mortality and reproduction were ... | 1998 | 9732475 |