| sensitivity of ethiopian aquatic macroinvertebrates to the pesticides endosulfan and diazinon, compared to literature data. | the aims of the present study were to present a methodology for toxicity tests that can be used when analytical resources to verify the test concentrations are limited, and to evaluate whether the sensitivity of a limited number of ethiopian species to pesticides differs from literature values for, mainly, temperate species. acute toxicity tests were performed using three ethiopian aquatic invertebrate species, one crustacean (diaphanosoma brachyurum) and two insects (anopheles pharoensis and cu ... | 2016 | 27221822 |
| developing antibodies from cholinesterase derived from prokaryotic expression and testing their feasibility for detecting immunogen content in daphnia magna. | to yield cholinesterase (che) from prokaryotic expression, the che gene that belongs to daphnia magna was amplified by reverse transcription-polymerase chain reaction (rt-pcr) using forward primer 5'-cccyggngcsat gatgtg-3' and reverse primer 5'-gyaagttrgcccaatatct-3'. to express the gene, one sequence of the amplified dna, which was able to encode a putative protein containing two conserved carboxylesterase domains, was connected to the prokaryotic expression vector pet-29a(+). the recombinant v ... | 0 | 26834012 |
| the environmental-endocrine basis of gynandromorphism (intersex) in a crustacean. | commensurate with the decline in many crustacean populations has been an accumulation in reports of sexually ambiguous individuals within these populations. the cause of gynandromorphism or intersex among crustaceans is unknown. we show that gynandromorphism in the branchiopod crustacean daphnia magna is initiated by the sex-determining hormone methyl farnesoate when levels of the hormone are intermediate between low levels that stimulate the production of broods containing all female offspring ... | 2006 | 17205107 |
| molecular evolution of the crustacean hyperglycemic hormone family in ecdysozoans. | crustacean hyperglycemic hormone (chh) family peptides are neurohormones known to regulate several important functions in decapod crustaceans such as ionic and energetic metabolism, molting and reproduction. the structural conservation of these peptides, together with the variety of functions they display, led us to investigate their evolutionary history. chh family peptides exist in insects (ion transport peptides) and may be present in all ecdysozoans as well. in order to extend the evolutiona ... | 2010 | 20184761 |
| purification and studies on characteristics of cholinesterases from daphnia magna. | due to their significant value in both economy and ecology, daphnia had long been employed to investigate in vivo response of cholinesterase (che) in anticholinesterase exposures, whereas the type constitution and property of the enzyme remained unclear. a type of che was purified from daphnia magna using a three-step procedure, i.e., triton x-100 extraction, ammonium sulfate precipitation, and diethylaminoethyl (deae)-sepharose™-fast-flow chromatography. according to sodium dodecyl sulfate poly ... | 0 | 23549850 |
| annotation of the daphnia magna nuclear receptors: comparison to daphnia pulex. | most nuclear receptors (nrs) are ligand-dependent transcription factors crucial in homeostatic physiological responses or environmental responses. we annotated the daphnia magna nrs and compared them to daphnia pulex and other species, primarily through phylogenetic analysis. daphnia species contain 26 nrs spanning all seven gene subfamilies. thirteen of the 26 receptors found in daphnia species phylogenetically segregate into the nr1 subfamily, primarily involved in energy metabolism and resour ... | 2014 | 25239664 |
| the hr97 (nr1l) group of nuclear receptors: a new group of nuclear receptors discovered in daphnia species. | the recently sequenced daphnia pulex genome revealed the nr1l nuclear receptor group consisting of three novel receptors. phylogenetic studies show that this group is related to the nr1i group (car/pxr/vdr) and the nr1j group (hr96), and were subsequently named hr97a/b/g. each of the hr97 paralogs from daphnia magna, a commonly used crustacean in toxicity testing, was cloned, sequenced, and partially characterized. phylogenetic analysis indicates that the hr97 receptors are present in primitive ... | 2014 | 25092536 |
| outlining eicosanoid biosynthesis in the crustacean daphnia. | eicosanoids are biologically active, oxygenated metabolites of three c20 polyunsaturated fatty acids. they act as signalling molecules within the autocrine or paracrine system in both vertebrates and invertebrates mainly functioning as important mediators in reproduction, the immune system and ion transport. the biosynthesis of eicosanoids has been intensively studied in mammals and it is known that they are synthesised from the fatty acid, arachidonic acid, through either the cyclooxygenase (co ... | 2008 | 18625039 |
| talen-mediated knock-in via non-homologous end joining in the crustacean daphnia magna. | transcription activator-like effector nucleases (talens) are versatile tools that enable the insertion of dna into different organisms. here, we confirmed talen-mediated knock-in via non-homologous end joining in the crustacean daphnia magna, a model organism for ecological and toxicological genomics. we tested two different talens, ey1 talen and ey2 talen, both of which target the eyeless locus. the donor dna plasmid, harbouring the h2b-gfp reporter gene, was designed to contain both talen targ ... | 2016 | 27819301 |
| sequence conservation and sexually dimorphic expression of the ftz-f1 gene in the crustacean daphnia magna. | identifying the genes required for environmental sex determination is important for understanding the evolution of diverse sex determination mechanisms in animals. orthologs of drosophila orphan receptor fushi tarazu factor-1 (ftz-f1) are known to function in genetic sex determination. in contrast, their roles in environmental sex determination remain unknown. in this study, we have cloned and characterized the ftz-f1 ortholog in the branchiopod crustacean daphnia magna, which produces males in ... | 2016 | 27138373 |
| the time- and age-dependent effects of the juvenile hormone analog pesticide, pyriproxyfen on daphnia magna reproduction. | pyriproxyfen is an insecticidal juvenile hormone analog that perturbs insect and tick development. pyriproxyfen also alters parthenogenic reproduction in non-target cladoceran species as it induces male production that can lead to a decrease in fecundity, a reduction in population density, and subsequent ecological effects. in this study, we investigate the impacts of pyriproxyfen on daphnia magna reproduction using a series of male production screening assays. these assays demonstrate that pyri ... | 2013 | 23714148 |
| expression and ecdysteroid responsiveness of the nuclear receptors hr3 and e75 in the crustacean daphnia magna. | ecdysteroids initiate signaling along multiple pathways that regulate various aspects of development, maturation, and reproduction in arthropods. signaling often involves the induction of downstream transcription factors that either positively or negatively regulate aspects of the pathway. we tested the hypothesis that crustaceans express the nuclear receptors hr3 (ortholog to vertebrate ror) and e75 (ortholog to vertebrate rev-erb) in response to ecdysteroid signaling. hr3 and e75 cdnas were cl ... | 2009 | 19631716 |
| environmental sex determination in the branchiopod crustacean daphnia magna: deep conservation of a doublesex gene in the sex-determining pathway. | sex-determining mechanisms are diverse among animal lineages and can be broadly divided into two major categories: genetic and environmental. in contrast to genetic sex determination (gsd), little is known about the molecular mechanisms underlying environmental sex determination (esd). the doublesex (dsx) genes play an important role in controlling sexual dimorphism in genetic sex-determining organisms such as nematodes, insects, and vertebrates. here we report the identification of two dsx gene ... | 2011 | 21455482 |
| common transcriptional mechanisms for visual photoreceptor cell differentiation among pancrustaceans. | a hallmark of visual rhabdomeric photoreceptors is the expression of a rhabdomeric opsin and uniquely associated phototransduction molecules, which are incorporated into a specialized expanded apical membrane, the rhabdomere. given the extensive utilization of rhabdomeric photoreceptors in the eyes of protostomes, here we address whether a common transcriptional mechanism exists for the differentiation of rhabdomeric photoreceptors. in drosophila, the transcription factors pph13 and orthodenticl ... | 2014 | 24991928 |
| population genetics of duplicated alternatively spliced exons of the dscam gene in daphnia and drosophila. | in insects and crustaceans, the down syndrome cell adhesion molecule (dscam) occurs in many different isoforms. these are produced by mutually exclusive alternative splicing of dozens of tandem duplicated exons coding for parts or whole immunoglobulin (ig) domains of the dscam protein. this diversity plays a role in the development of the nervous system and also in the immune system. structural analysis of the protein suggested candidate epitopes where binding to pathogens could occur. these epi ... | 2011 | 22174757 |
| culmination of low-dose pesticide effects. | pesticides applied in agriculture can affect the structure and function of nontarget populations at lower doses and for longer timespans than predicted by the current risk assessment frameworks. we identified a mechanism for this observation. the populations of an aquatic invertebrate (culex pipiens) exposed over several generations to repeated pulses of low concentrations of the neonicotinoid insecticide (thiacloprid) continuously declined and did not recover in the presence of a less sensitive ... | 2013 | 23859631 |
| proteomic analysis of daphnia magna hints at molecular pathways involved in defensive plastic responses. | phenotypic plasticity in defensive traits occurs in many species when facing heterogeneous predator regimes. the waterflea daphnia is well-known for showing a variety of these so called inducible defences. however, molecular mechanisms underlying this plasticity are poorly understood so far. we performed proteomic analysis on daphnia magna exposed to chemical cues of the predator triops cancriformis. d. magna develops an array of morphological changes in the presence of triops including changes ... | 2014 | 24762235 |
| biotic interactions govern genetic adaptation to toxicants. | the genetic recovery of resistant populations released from pesticide exposure is accelerated by the presence of environmental stressors. by contrast, the relevance of environmental stressors for the spread of resistance during pesticide exposure has not been studied. moreover, the consequences of interactions between different stressors have not been considered. here we show that stress through intraspecific competition accelerates microevolution, because it enhances fitness differences between ... | 0 | 25833856 |
| ecotoxicity assessment of particulate matter emitted from heavy-duty diesel-powered vehicles: influence of leaching conditions. | concerns regarding the environmental impact of diesel exhaust particulate matter (dpm) have increased in recent years. following emission to the atmosphere, these fine materials can sorb many contaminants at their surface, which can subsequently be released, for instance, due to physicochemical environmental changes. the desorption of contaminants from particulate matter will increase the environmental pollution and can promote ecotoxicological effects. in this context, the objective of this stu ... | 2017 | 28233212 |
| ecotoxicity assessment of ionic as(iii), as(v), in(iii) and ga(iii) species potentially released from novel iii-v semiconductor materials. | iii-v materials such as indium arsenide (inas) and gallium arsenide (gaas) are increasingly used in electronic and photovoltaic devices. the extensive application of these materials may lead to release of iii-v ionic species during semiconductor manufacturing or disposal of decommissioned devices into the environment. although arsenic is recognized as an important contaminant due to its high toxicity, there is a lack of information about the toxic effects of indium and gallium ions. in this stud ... | 2017 | 28231503 |
| correlation between acute toxicity for daphnia magna, aliivibrio fischeri and physicochemical variables of the leachate produced in landfill simulator reactors. | due to the diversified nature of municipal solid waste and the different stages of its decomposition, the formed leachates result in a complex chemical mixture with toxic potential. these chemicals can cause environmental problems, such as the contamination of surface or groundwater, thus affecting the balance of aquatic ecosystems. the aim of our study was to evaluate the acute toxicity of leachates in daphnia magna and aliivibrio fischeri and to identify the main physicochemical variables that ... | 2017 | 28076700 |
| synthesis, characterization and toxicological evaluation of cr₂o₃ nanoparticles using daphnia magna and aliivibrio fischeri. | chromium iii oxide (cr2o3) nanoparticles (nps) are used in pigments for ceramics, dyes, paints and cosmetics. however, few studies addressing the toxic potential of these nps have been reported in the literature. thus, this research aimed to evaluate the acute and chronic effects of cr2o3 nps through acute toxicity tests with daphnia magna and aliivibrio fischeri and chronic toxicity tests with daphnia magna. cr2o3 nps were synthesized by the sol-gel method and characterized through tem, x-ray d ... | 2016 | 26890188 |
| lanthanide ecotoxicity: first attempt to measure environmental risk for aquatic organisms. | the geochemical cycles of lanthanides are being disrupted by increasing global production and human use, but their ecotoxicity is not fully characterized. in this study, the sensitivity of aliivibrio fischeri and pseudokirchneriella subcapitata to lanthanides increased with atomic number, while daphnia magna, heterocypris incongruens, brachionus calyciflorus and hydra attenuata were equally sensitive to the tested elements. in some cases, a marked decrease in exposure concentrations was observed ... | 2015 | 25645063 |
| arsenate (as v) in water: quantitative sensitivity relationships among biomarker, ecotoxicity and genotoxicity endpoints. | it is useful to test ecotoxicity and genotoxicity endpoints in the environmental impact assessment. here, we compare and discuss ecotoxicity and genotoxicity effects in organisms in response to exposure to arsenate (as v) in solution. eco(geno)toxicity responses in aliivibrio fischeri, lytechinus variegatus, daphnia magna, skeletonema costatum and vicia faba were analyzed by assessing different endpoints: biomass growth, peroxidase activity, mitotic index, micronucleus frequency, and lethality i ... | 2013 | 23597676 |
| sensitivity of different aquatic bioassays in the assessment of a new natural formicide. | agrochemicals have the potential to cause deleterious effects on living organisms and therefore they must be subjected to various (eco)toxicological studies and monitoring programs in order to protect human health and the environment. the aim of this study was to assess the ecotoxicity of a new natural formicide with a battery of three classical and three ecotox-kit tests. the former tests were performed with aliivibrio fischeri bacteria (lumistox test), the cladoceran daphnia magna and pseudoki ... | 2013 | 23030441 |
| assessment of sediment quality and pore water ecotoxicity in kebir rhumel basin (ne-algeria): a combined approach. | the objectives of this study are to use different approaches to assess the current pollution status in the wadis of the kebir rhumel basin. first, sediment trace metal contents were measured by flame atomic absorption spectroscopy. then, sediment quality was assessed on the basis of contamination assessment indexes such as: geoaccumulation index (igeo), contamination factor (c(f)), contamination degree (c(d)), sediment pollution index (spi) and seq guidelines (consensus sediment quality guidelin ... | 2012 | 22233919 |
| water recycle as a must: decolorization of textile wastewaters by plant-associated fungi. | textile dye effluents are among the most problematic pollutants because of their toxicity on several organisms and ecosystems. low cost and ecocompatible bioremediation processes offer a promising alternative to the conventional and aspecific physico-chemical procedures adopted so far. here, microorganisms resident on three real textile dyeing effluent were isolated, characterized, and tested for their decolorizing performances. although able to survive on these real textile-dyeing wastewaters, ... | 2014 | 23553673 |
| mechanism-specific and whole-organism ecotoxicity of mono-rhamnolipids. | biosurfactants like rhamnolipids are promising alternatives to chemical surfactants in a range of applications. a wider use requires an analysis of their environmental fate and their ecotoxicological potential. in the present study mono-rhamnolipids produced by a recombinant pseudomonas putida strain were analyzed using the green toxicology concept for acute and mechanism-specific toxicity in an ecotoxicological test battery. acute toxicity tests with the invertebrate daphnia magna and with zebr ... | 2016 | 26802344 |
| high levan production by bacillus licheniformis ns032 using ammonium chloride as the sole nitrogen source. | in this study, levan production by bacillus licheniformis ns032 isolated from a petroleum sludge sample was investigated. high levan yield was obtained in a wide range of sucrose concentrations (up to 400 g/l) and, contrary to most levan-producing strains, using ammonium chloride as the sole n source. interaction between sucrose, ammonium chloride, and initial ph of the medium in a low sucrose (60-200 g/l) and a high sucrose (300-400 g/l) system was analyzed by response surface methodology. acco ... | 2015 | 25592434 |
| aquatic toxicity and biodegradability of a surfactant produced by bacillus subtilis ica56. | in this work, the environmental compatibility of a biosurfactant produced by a bacillus subtilis strain isolated from the soil of a brazilian mangrove was investigated. the biosurfactant, identified as surfactin, is able to reduce surface tension (st) to 31.5 ± 0.1 mn m(-1) and exhibits a lowcritical micelle concentration (cmc) value (0.015 ± 0.003 g l(-1)). the highest crude biosurfactant concentration (224.3 ± 1.9 mg l(-1)) was reached at 72 h of fermentation. acute toxicity tests, carried out ... | 2017 | 27791474 |
| derivation of guideline values for gold (iii) ion toxicity limits to protect aquatic ecosystems. | this study focused on estimating the toxicity values of various aquatic organisms exposed to gold (iii) ion (au(3+)), and to propose maximum guideline values for au(3+) toxicity that protect the aquatic ecosystem. a comparative assessment of methods developed in australia and new zealand versus the european community (ec) was conducted. the test species used in this study included two bacteria (escherichia coli and bacillus subtilis), one alga (pseudokirchneriella subcapitata), one euglena (eugl ... | 2014 | 24094731 |
| low-dose effects: nonmonotonic responses for the toxicity of a bacillus thuringiensis biocide to daphnia magna. | currently, there is a trend toward an increasing use of biopesticides assumed to be environmentally friendly, such as bacillus thuringiensis (bt). studies of the bt toxicity to nontarget organisms have reported low effects at high exposure levels, which is interpreted as indicating negligible risk to nontarget organisms. we investigated the response of the nontarget organism daphnia magna to waterborne dipel es, a globally used bt formulation. neonates and adults were exposed for 48 h to a wide ... | 2017 | 28001053 |
| interactions between bt crops and aquatic ecosystems: a review. | the term bt crops collectively refers to crops that have been genetically modified to include a gene (or genes) sourced from bacillus thuringiensis (bt) bacteria. these genes confer the ability to produce proteins toxic to certain insect pests. the interaction between bt crops and adjacent aquatic ecosystems has received limited attention in research and risk assessment, despite the fact that some bt crops have been in commercial use for 20 yr. reports of effects on aquatic organisms such as dap ... | 2016 | 27530353 |
| daphnia magna negatively affected by chronic exposure to purified cry-toxins. | cry-toxin genes originating from bacillus thuringiensis are inserted into genetically modified (gm) plants, often called bt-plants, to provide insect resistance to pests. significant amounts of bt-plant residues, and thus cry-toxins, will be shed to soil and aquatic environments. we exposed daphnia magna to purified cry1ab and cry2aa toxins for the full life-span of the animals. we used single toxins in different doses and combinations of toxins and roundup(®), another potential stressor on the ... | 2016 | 26993955 |
| chronic responses of daphnia magna under dietary exposure to leaves of a transgenic (event mon810) bt-maize hybrid and its conventional near-isoline. | insect resistance is the second most common trait globally in cultivated genetically modified (gm) plants. resistance is usually obtained by introducing into the plant's genome genes from the bacterium bacillus thuringiensis (bt) coding for insecticidal proteins (cry proteins or toxins) that target insect pests. the aim of this study was to examine the hypothesis that a chronic, high-dose dietary exposure to leaves of a bt-maize hybrid (gm event mon810, expressing a transgenic or recombinant cry ... | 2015 | 26262442 |
| transgenic bacillus thuringiensis (bt) rice is safer to aquatic ecosystems than its non-transgenic counterpart. | rice lines genetically modified with the crystal toxin genes from bacillus thuringiensis (bt) have experienced rapid development, with biosafety certificates for two bt rice lines issued in 2009. there has still been no commercial release of these lines yet due to public concerns about human health and environmental risks. some studies confirmed that bt rice was as safe as conventional rice to non-target organisms when pesticides were not applied, however, pesticides are still required in bt ric ... | 2014 | 25105299 |
| daphnia predation on the amphibian chytrid fungus and its impacts on disease risk in tadpoles. | direct predation upon parasites has the potential to reduce infection in host populations. for example, the fungal parasite of amphibians, batrachochytrium dendrobatidis (bd), is commonly transmitted through a free-swimming zoospore stage that may be vulnerable to predation. potential predators of bd include freshwater zooplankton that graze on organisms in the water column. we tested the ability of two species of freshwater crustacean (daphnia magna and d. dentifera) to consume bd and to reduce ... | 2013 | 24324864 |
| chiral triazole fungicide difenoconazole: absolute stereochemistry, stereoselective bioactivity, aquatic toxicity, and environmental behavior in vegetables and soil. | in this study, the systemic assessments of the stereoisomers of triazole fungicide difenoconazole are reported for the first time, including absolute stereochemistry, stereoselective bioactivity toward pathogens (alternaria sonali, fulvia fulva, botrytis cinerea, and rhizoctonia solani), and toxicity toward aquatic organisms (scenedesmus obliquus, daphnia magna, and danio rerio). moreover, the stereoselective degradation of difenoconazole in vegetables (cucumber, cucumis sativus and tomato, lyco ... | 2013 | 23451708 |
| bioactivity, toxicity and dissipation of hexaconazole enantiomers. | in this study, the bioactivity, acute toxicity and dissipation in vegetables of the individual enantiomers of the fungicide hexaconazole had been investigated. the optical pure single enantiomers were prepared and the bioactivity of (+)-, (-)- and rac-hexaconazole was tested using four target fungi including colletotrichum gloeosporioides penz, alternaria solani, alternaria mali roberts and monilinia fructicola. the results showed (-)-hexaconazole was always more active than (+)-hexaconazole wit ... | 2013 | 24206830 |
| relevance of the bioavailable fraction of ddt and its metabolites in freshwater sediment toxicity: new insight into the mode of action of these chemicals on dictyostelium discoideum. | in this work, the toxicity of lake sediments contaminated with ddt and its metabolites ddd and dde (collectively, ddx) was evaluated with widely used toxicity tests (i.e., vibrio fischeri, daphnia magna, pseudokirchneriella subcapitata, and lumbriculus variegatus) and with the social amoeba dictyostelium discoideum, a model organism that is also suitable for studying pollutant-induced alterations at the molecular and cellular levels. although the ddx concentration in the sediments was high (732. ... | 2016 | 27340883 |
| ecotoxicological survey of mnei and y65r-mnei proteins as new potential high-intensity sweeteners. | low-calorie sweeteners are widespread. they are routinely introduced into commonly consumed food such as diet sodas, cereals, and sugar-free desserts. recent data revealed the presence in considerable quantities of some of these artificial sweeteners in water samples qualifying them as a class of potential new emerging contaminants. this study aimed at evaluating the ecotoxicity profile of mnei and y65r-mnei, two engineered products derived from the natural protein monellin, employing representa ... | 2017 | 28251536 |
| effects of ammonia and density on filtering of commensal and pathogenic escherichia coli by the cladoceran daphnia magna. | grazing by cladocerans can reduce the survival of enteric bacteria associated with fecal pollution. this study examined the potential of daphnia magna to filter commensal and pathogenic escherichia coli of human origin. grazing on commensal and pathogenic bacteria was comparable, but slightly greater at 20 compared to 15 and 25°c. filtering activity was strongly dependent on d. magna and e. coli densities at environmentally relevant bacterial concentrations. maximum feeding rates were >10(7) cel ... | 2016 | 27817111 |
| antimicrobial filtration with electrospun poly(vinyl alcohol) nanofibers containing benzyl triethylammonium chloride: immersion, leaching, toxicity, and filtration tests. | antimicrobial electrospun poly(vinyl alcohol) (pva) nanofibers were synthesized by impregnating benzyl triethylammonium chloride (bteac) as an antimicrobial agent into pva nanofibers. the bteac-pva nanofibers were heat-methanol treated during the preparation for various tests. the bteac-pva nanofibers became more hydrophilic than the pva nanofibers due to incorporation of bteac. through heat-methanol treatment, thermal property, crystallinity, and water stability of bteac-pva nanofibers were imp ... | 2017 | 27750171 |
| an integrated study on antimicrobial activity and ecotoxicity of quantum dots and quantum dots coated with the antimicrobial peptide indolicidin. | this study attempts to evaluate the antimicrobial activity and the ecotoxicity of quantum dots (qds) alone and coated with indolicidin. to meet this objective, we tested the level of antimicrobial activity on gram-positive and gram-negative bacteria, and we designed an ecotoxicological battery of test systems and indicators able to detect different effects using a variety of end points. the antibacterial activity was analyzed against staphylococcus aureus (atcc 6538), pseudomonas aeruginosa (atc ... | 2017 | 27616887 |
| development of phytotoxicity indexes and their correlation with ecotoxicological, stability and physicochemical parameters during passive composting of poultry manure. | both raw and composted poultry manure is applied as soil amendment. the aims of this study were: (1) to develop phytotoxicity indexes for organic wastes and composts, and (2) to assess the correlation among phytotoxicity indexes, ecotoxicological endpoints and stability and physicochemical parameters during passive composting of poultry manure. six 2-m(3) composting piles were constructed and four parameter groups (physicochemical and microbiological parameters, ecotoxicological endpoints, and b ... | 2016 | 27185192 |
| the time is right to focus on model organism metabolomes. | model organisms are an essential component of biological and biomedical research that can be used to study specific biological processes. these organisms are in part selected for facile experimental study. however, just as importantly, intensive study of a small number of model organisms yields important synergies as discoveries in one area of science for a given organism shed light on biological processes in other areas, even for other organisms. furthermore, the extensive knowledge bases compi ... | 2016 | 26891337 |
| inactivation mechanism of chlorination in escherichia coli internalized in limnoithona sinensis and daphnia magna. | zooplankton may harbor microorganisms in the aquatic environment, thus protecting them from disinfection during drinking water treatment. however, few studies have evaluated the protective effect of internalization by zooplankton against bacterial disinfection. in this study, we investigated the role of zooplankton (limnoithona sinensis and daphnia magna) as a refuge for ingested bacteria against inactivation by chlorination. only 30% of chlorine reached the internalized bacteria inside the dige ... | 2016 | 26624518 |
| decolorization of acid and basic dyes: understanding the metabolic degradation and cell-induced adsorption/precipitation by escherichia coli. | escherichia coli strain dh5α was successfully employed in the decolorization of commercial anthraquinone and azo dyes, belonging to the general classes of acid or basic dyes. the bacteria showed an aptitude to survive at different ph values on any dye solution tested, and a rapid decolorization was obtained under aerobic conditions for the whole collection of dyes. a deep investigation about the mode of action of e. coli was carried out to demonstrate that dye decolorization mainly occurred via ... | 2015 | 26062529 |
| eco-genotoxicity of six anticancer drugs using comet assay in daphnids. | the eco-genotoxicity of six anti-neoplastic drugs, 5-fluorouracil, capecitabine, cisplatin, doxorubicin, etoposide, and imatinib, belonging to five classes of anatomical therapeutic classification (atc), was studied applying the in vivo comet assay on cells from whole organisms of daphnia magna and ceriodaphnia dubia. for the first time, this test was performed in c. dubia. in addition, to have a wider genotoxic/mutagenic profile of the anticancer drugs selected, sos chromotest and salmonella mu ... | 2015 | 25638790 |
| high concentrations of protein test substances may have non-toxic effects on daphnia magna: implications for regulatory study designs and ecological risk assessments for gm crops. | laboratory testing for possible adverse effects of insecticidal proteins on non-target organisms (ntos) is an important part of many ecological risk assessments for regulatory decision-making about the cultivation of insect-resistant genetically modified (irgm) crops. to increase confidence in the risk assessments, regulatory guidelines for effects testing specify that representative surrogate species for ntos are exposed to concentrations of insecticidal proteins that are in excess of worst-cas ... | 2014 | 25523175 |
| novel composite plastics containing silver(i) acylpyrazolonato additives display potent antimicrobial activity by contact. | new silver(i) acylpyrazolonato derivatives displaying a mononuclear, polynuclear, or ionic nature, as a function of the ancillary azole ligands used in the synthesis, have been fully characterized by thermal analysis, solution nmr spectroscopy, solid-state ir and nmr spectroscopies, and x-ray diffraction techniques. these derivatives have been embedded in polyethylene (pe) matrix, and the antimicrobial activity of the composite materials has been tested against three bacterial strains (e. coli, ... | 2015 | 25358838 |
| tertiary treatment for wastewater reuse based on the daphnia magna filtration - comparison with conventional tertiary treatments. | tertiary treatments are required to permit safe reuse of wastewater. the performance of a new biological tertiary treatment based on the filtration by a population of daphnia magna was studied and compared with the performance of other conventional tertiary treatments such as coagulation-flocculation, settling tank, disc filtration, sand filtering and ultraviolet (uv) light. the analysis was based on the efficiency in the particle removal and escherichia coli inactivation. the daphnia magna trea ... | 2014 | 25116502 |
| peracetic acid for secondary effluent disinfection: a comprehensive performance assessment. | the paper is a review of previous research on secondary effluent disinfection by peracetic acid (paa) integrated with new data about the effect of a preliminary flash-mixing step. the process was studied at bench and pilot scale to assess its performance for discharge in surface water and agricultural reuse (target microorganisms: escherichia coli and faecal coliform bacteria). the purposes of the research were: (1) determining paa decay and disinfection kinetics as a function of operating param ... | 2013 | 24355852 |
| particle size, surface charge and concentration dependent ecotoxicity of three organo-coated silver nanoparticles: comparison between general linear model-predicted and observed toxicity. | mechanism underlying nanotoxicity has remained elusive. hence, efforts to understand whether nanoparticle properties might explain its toxicity are ongoing. considering three different types of organo-coated silver nanoparticles (agnps): citrate-coated agnp, polyvinylpyrrolidone-coated agnp, and branched polyethyleneimine-coated agnp, with different surface charge scenarios and core particle sizes, herein we systematically evaluate the potential role of particle size and surface charge on the to ... | 2014 | 24091120 |
| use of ecotoxicity test and ecoscores to improve the management of polluted soils: case of a secondary lead smelter plant. | with the rise of sustainable development, rehabilitation of brownfield sites located in urban areas has become a major concern. management of contaminated soils in relation with environmental and sanitary risk concerns is therefore a strong aim needing the development of both useful tools for risk assessment and sustainable remediation techniques. for soils polluted by metals and metalloids (mte), the criteria for landfilling are currently not based on ecotoxicological tests but on total mte con ... | 2013 | 23328625 |
| whole-cell bacterial biosensors for rapid and effective monitoring of heavy metals and inorganic pollutants in wastewater. | the increasing number of potentially harmful pollutants in the wastewater effluent discharge necessitates the need for the development of fast and cost effective analytical techniques for extensive monitoring programmes to assess the effectiveness of the treatment process. this study compared the use of bacterial biosensors to the conventional daphnia magna assay, chemical oxygen demand (cod) and biochemical oxygen demand (bod) tests as well as chemical analysis, for monitoring the toxicity of w ... | 2011 | 21904738 |
| efficacy of fungal decolorization of a mixture of dyes belonging to different classes. | dyes are the most difficult constituents to remove by conventional biological wastewater treatment. colored wastewater is mainly eliminated by physical and chemical procedures, which are very expensive and have drawbacks. therefore, the advantage of using biological processes, such as the biotransformation of dyes, is that they may lead to complete mineralization or formation of less toxic products. to prove the possibility of using fungal processes for decolorization and other applications, the ... | 2015 | 26273256 |
| effectiveness of dyes removal by mixed fungal cultures and toxicity of their metabolites. | decolorization of brilliant green (0.06 g/l), evans blue (0.15 g/l), and their mixture (total concentration 0.08 g/l, proportion 1:1 w/w) by fungi was studied. fungal strains [pleurotus ostreatus (bwph), gloeophyllum odoratum (dca), and fusarium oxysporum (g1)] were used separately and as a mixture of them. zootoxicity (daphnia magna) and phytotoxicity (lemna minor) changes were estimated after the end of experiment. mixtures of fungal strains were less effective in decolorization process than t ... | 2013 | 23687394 |
| role of water fleas (daphnia magna) in the accumulation of avian influenza viruses from the surrounding water. | to determine the role of water fleas in accumulating avian influenza viruses (aiv) from the surrounding water and to estimate their role as a vector of aiv. | 2012 | 22269863 |
| wrecking the curve: altered functional response of tetragoneuria (odonata: corduliidae) naiads infected with metacercariae of haematoloechus floedae. | the ubiquity of host-parasite interactions and their potential for substantial representation, in terms of overall biomass, within ecosystems suggests that parasites have the capacity to influence energy flow within an ecosystem. while the influence of certain parasites on prey behavior has been well-documented, parasites could also exert an influence on ecosystem dynamics by influencing predator feeding behavior. the functional response of tetragoneuria naiads was characterized by presenting na ... | 2017 | 28118094 |
| single-nucleotide polymorphisms of two closely related microsporidian parasites suggest a clonal population expansion after the last glaciation. | the mode of reproduction of microsporidian parasites has remained puzzling since many decades. it is generally accepted that microsporidia are capable of sexual reproduction, and that some species have switched to obligate asexuality, but such process had never been supported with population genetic evidence. we examine the mode of reproduction of hamiltosporidium tvaerminnensis and hamiltosporidium magnivora, two closely related microsporidian parasites of the widespread freshwater crustacean d ... | 2013 | 23163569 |
| epidemiology of a daphnia-multiparasite system and its implications for the red queen. | the red queen hypothesis can explain the maintenance of host and parasite diversity. however, the red queen requires genetic specificity for infection risk (i.e., that infection depends on the exact combination of host and parasite genotypes) and strongly virulent effects of infection on host fitness. a european crustacean (daphnia magna)--bacterium (pasteuria ramosa) system typifies such specificity and high virulence. we studied the north american host daphnia dentifera and its natural parasit ... | 2012 | 22761826 |
| the influence of bacteria-dominated diets on daphnia magna somatic growth, reproduction, and lipid composition. | we explored how dietary bacteria affect the life history traits and biochemical composition of daphnia magna, using three bacteria taxa with very different lipid composition. our objectives were to (1) examine whether and how bacteria-dominated diets affect daphnia survival, growth, and fecundity, (2) see whether bacteria-specific fatty acid (fa) biomarkers accrued in daphnia lipids, and (3) explore the quantitative relationship between bacteria availability in daphnia diets and the amounts of b ... | 2012 | 22564190 |
| expression of parasite virulence at different host population densities under natural conditions. | it has recently been suggested that the expression of parasite virulence depends on host population density, such that infected hosts have a higher sensitivity to density, and thus reach their carrying capacity earlier than uninfected hosts. in this scenario, parasite-induced reduction in fitness (i.e., virulence) increases with host density. we tested this hypothesis experimentally, using outdoor mesocosm populations of daphnia magna infected by the microsporidian octosporea bayeri. contrary to ... | 2009 | 19219457 |
| male-biased sex-ratio distortion caused by octosporea bayeri, a vertically and horizontally-transmitted parasite of daphnia magna. | female-biased sex-ratio distortion is often observed in hosts infected with vertically-transmitted microsporidian parasites. this bias is assumed to benefit the spread of the parasite, because male offspring usually do not transmit the parasite further. the present study reports on sex-ratio distortion in a host-parasite system with both horizontal and vertical parasite transmission: the microsporidium octosporea bayeri and its host, the planktonic cladoceran daphnia magna. in laboratory and fie ... | 2008 | 18190917 |
| the genotype specific competitive ability does not correlate with infection in natural daphnia magna populations. | different evolutionary hypotheses predict a correlation between the fitness of a genotype in the absence of infection and the likelihood to become infected. the cost of resistance hypothesis predicts that resistant genotypes pay a cost of being resistant and are less fit in the absence of parasites. the inbreeding-infection hypothesis predicts that the susceptible individuals are less fit due to inbreeding depression. | 2007 | 18060074 |
| a short term benefit for outcrossing in a daphnia metapopulation in relation to parasitism. | because host-parasite interactions are often specific to the host and parasite genotype, it may be important whether a host reproduces by selfing or outcrossing. the latter is associated with higher genetic diversity among the offspring and may reduce parasite success. here, we test whether outbred offspring of daphnia magna have an advantage over selfed offspring in the presence of a parasite transmitted from mothers to offspring. using outdoor mesocosms, we set up monoclonal and polyclonal hos ... | 2007 | 17456451 |
| quantitative pcr to detect, discriminate and quantify intracellular parasites in their host: an example from three microsporidians in daphnia. | reliable detection, discrimination and quantification of parasites are important for host-parasite studies and diagnostics. microsporidial infections are problematic in this respect. their discrimination and quantification using light microscopy is difficult because spores are the only light microscopically visible form of the parasite and they offer few distinct characters. we developed a quantitative pcr (qpcr) assay based on sybr green chemistry to quantify the microsporidia glugoides intesti ... | 2006 | 16563203 |
| apparent seasonality of parasite dynamics: analysis of cyclic prevalence patterns. | seasonal disease dynamics are common in nature, but their causes are often unknown. our case study provides insight into the cyclic prevalence pattern of the horizontally and vertically transmitted microsporidium octosporea bayeri in its daphnia magna host. data from several populations over a four year period revealed a regular prevalence increase during summer and a decrease over winter when hosts underwent diapause. prevalence also decreased after summer diapause indicating that the decline i ... | 2006 | 16555788 |
| different mechanisms of transmission of the microsporidium octosporea bayeri: a cocktail of solutions for the problem of parasite permanence. | periods of low host density impose a constraint on parasites with direct transmission, challenging their permanence in the system. the microsporidium octosporea bayeri faces such constraint in a metapopulation of its host, the cladoceran daphnia magna, where ponds frequently lose their host population due to ponds drying out in summer and freezing in winter. we conducted experiments aimed to investigate the mechanisms of transmission of o. bayeri, and discuss how these mechanisms could contribut ... | 2005 | 15991493 |
| mixed inoculations of a microsporidian parasite with horizontal and vertical infections. | mixed infections, where more than one parasite genotype is present in a single host, have been suggested to be an important factor in host-parasite interactions. as the host represents a limited resource, co-infecting parasite genotypes are expected to be under resource competition. competition will not only modify the survival of the co-infecting genotypes, but is also likely to affect total within-host parasite growth as well as host survival and reproduction. we measured parasite infectivity ... | 2005 | 15742220 |
| octosporea bayeri: fumidil b inhibits vertical transmission in daphnia magna. | microsporidia are a highly successful and ecologically diverse group of parasites, and thus represent interesting model systems for research on host-parasite interactions. however, such research often requires the ability to cure hosts of infections, a difficult task, given the short lifespan of most invertebrates and the efficient vertical transmission of some parasites. to our knowledge, few treatments are available to cure microsporidiosis in invertebrate hosts, and protocols have not yet bee ... | 2005 | 15639141 |
| within-host dynamics of a microsporidium with horizontal and vertical transmission: octosporea bayeri in daphnia magna. | the fresh-water crustacean daphnia magna may acquire an infection with the microsporidium octosporea bayeri either by ingesting spores from the water (horizontally), or directly from its mother (vertically). due to differences in the time and mechanisms of transmission, horizontal and vertical infections may lead to differences in the growth of the parasite within the host. this may influence parasite virulence, transmission to new hosts, and, consequently, epidemiology and evolution. here we de ... | 2004 | 15002901 |
| the effects of parasitism and inbreeding on the competitive ability in daphnia magna: evidence for synergistic epistasis. | synergistic epistasis for fitness is often assumed in models of how selection acts on the frequency and distribution of deleterious mutations. evidence for synergistic epistasis would exist if the logarithm of fitness declines more quickly with number of deleterious mutations, than predicted by a linear decline. this can be studied indirectly by quantifying the effect of different levels of inbreeding on fitness. here, six sets (different genetic backgrounds) of three increasingly inbred daphnia ... | 2003 | 14635913 |
| survival, reproduction, growth, and parasite resistance of aquatic organisms exposed on-site to wastewater treated by advanced treatment processes. | advanced wastewater treatment technologies are generally known to be an effective tool for reducing micropollutant discharge into the aquatic environment. nevertheless, some processes such as ozonation result in stable transformation products with often unknown toxicity. in the present study, whole effluents originating from nine different steps of advanced treatment combinations were compared for their aquatic toxicity. assessed endpoints were survival, growth and reproduction of lumbriculus va ... | 2017 | 28284153 |
| parasitism drives host genome evolution: insights from the pasteuria ramosa-daphnia magna system. | because parasitism is thought to play a major role in shaping host genomes, it has been predicted that genomic regions associated with resistance to parasites should stand out in genome scans, revealing signals of selection above the genomic background. to test whether parasitism is indeed such a major factor in host evolution and to better understand host-parasite interaction at the molecular level, we studied genome-wide polymorphisms in 97 genotypes of the planktonic crustacean daphnia magna ... | 2017 | 28230237 |
| the genetic basis of resistance and matching-allele interactions of a host-parasite system: the daphnia magna-pasteuria ramosa model. | negative frequency-dependent selection (nfds) is an evolutionary mechanism suggested to govern host-parasite coevolution and the maintenance of genetic diversity at host resistance loci, such as the vertebrate mhc and r-genes in plants. matching-allele interactions of hosts and parasites that prevent the emergence of host and parasite genotypes that are universally resistant and infective are a genetic mechanism predicted to underpin nfds. the underlying genetics of matching-allele interactions ... | 2017 | 28222092 |
| sex as a strategy against rapidly evolving parasites. | why is sex ubiquitous when asexual reproduction is much less costly? sex disrupts coadapted gene complexes; it also causes costs associated with mate finding and the production of males who do not themselves bear offspring. theory predicts parasites select for host sex, because genetically variable offspring can escape infection from parasites adapted to infect the previous generations. we examine this using a facultative sexual crustacean, daphnia magna, and its sterilizing bacterial parasite, ... | 2016 | 28003455 |
| the trans-generational impact of population density signals on host-parasite interactions. | the density of a host population is a key parameter underlying disease transmission, but it also has implications for the expression of disease through its effect on host physiology. in response to higher densities, individuals are predicted to either increase their immune investment in response to the elevated risk of parasitism, or conversely to decrease their immune capacity as a consequence of the stress of a crowded environment. however, an individual's health is shaped by many different fa ... | 2016 | 27887563 |
| combined effects of dietary polyunsaturated fatty acids and parasite exposure on eicosanoid-related gene expression in an invertebrate model. | eicosanoids derive from essential polyunsaturated fatty acids (pufa) and play crucial roles in immunity, development, and reproduction. however, potential links between dietary pufa supply and eicosanoid biosynthesis are poorly understood, especially in invertebrates. using daphnia magna and its bacterial parasite pasteuria ramosa as model system, we studied the expression of genes coding for key enzymes in eicosanoid biosynthesis and of genes related to oogenesis in response to dietary arachido ... | 2016 | 27421236 |
| a population biology perspective on the stepwise infection process of the bacterial pathogen pasteuria ramosa in daphnia. | the infection process of many diseases can be divided into series of steps, each one required to successfully complete the parasite's life and transmission cycle. this approach often reveals that the complex phenomenon of infection is composed of a series of more simple mechanisms. here we demonstrate that a population biology approach, which takes into consideration the natural genetic and environmental variation at each step, can greatly aid our understanding of the evolutionary processes shap ... | 2016 | 27015951 |
| the red queen lives: epistasis between linked resistance loci. | a popular theory explaining the maintenance of genetic recombination (sex) is the red queen theory. this theory revolves around the idea that time-lagged negative frequency-dependent selection by parasites favors rare host genotypes generated through recombination. although the red queen has been studied for decades, one of its key assumptions has remained unsupported. the signature host-parasite specificity underlying the red queen, where infection depends on a match between host and parasite g ... | 2016 | 26763092 |
| infections by pasteuria do not protect its natural host daphnia magna from subsequent infections. | the existence of immunological memory in invertebrates remains a contentious topic. exposure of daphnia magna crustaceans to a noninfectious dose of the bacterium pasteuria ramosa has been reported to reduce the chance of future infection upon exposure to higher doses. using clonal hosts and parasites, we tested whether initial exposure of the host to the parasite (priming), followed by clearing of the parasite with antibiotic, protects the host from a second exposure (challenge). our experiment ... | 2016 | 26709232 |
| transcriptome profiling during a natural host-parasite interaction. | infection outcome in some coevolving host-pathogens is characterised by host-pathogen genetic interactions, where particular host genotypes are susceptible only to a subset of pathogen genotypes. to identify candidate genes responsible for the infection status of the host, we exposed a daphnia magna host genotype to two bacterial strains of pasteuria ramosa, one of which results in infection, while the other does not. at three time points (four, eight and 12 h) post pathogen exposure, we sequenc ... | 2015 | 26311167 |
| host age modulates within-host parasite competition. | in many host populations, one of the most striking differences among hosts is their age. while parasite prevalence differences in relation to host age are well known, little is known on how host age impacts ecological and evolutionary dynamics of diseases. using two clones of the water flea daphnia magna and two clones of its bacterial parasite pasteuria ramosa, we examined how host age at exposure influences within-host parasite competition and virulence. we found that multiply-exposed hosts we ... | 2015 | 25994010 |
| expression of parasite genetic variation changes over the course of infection: implications of within-host dynamics for the evolution of virulence. | how infectious disease agents interact with their host changes during the course of infection and can alter the expression of disease-related traits. yet by measuring parasite life-history traits at one or few moments during infection, studies have overlooked the impact of variable parasite growth trajectories on disease evolution. here we show that infection-age-specific estimates of host and parasite fitness components can reveal new insight into the evolution of parasites. we do so by charact ... | 2015 | 25761710 |
| host age modulates parasite infectivity, virulence and reproduction. | host age is one of the most striking differences among hosts within most populations, but there is very little data on how age-dependent effects impact ecological and evolutionary dynamics of both the host and the parasite. here, we examined the influence of host age (juveniles, young and old adults) at parasite exposure on host susceptibility, fecundity and survival as well as parasite transmission, using two clones of the water flea daphnia magna and two clones of its bacterial parasite pasteu ... | 2015 | 25661269 |
| genetic architecture of resistance in daphnia hosts against two species of host-specific parasites. | understanding the genetic architecture of host resistance is key for understanding the evolution of host-parasite interactions. evolutionary models often assume simple genetics based on few loci and strong epistasis. it is unknown, however, whether these assumptions apply to natural populations. using a quantitative trait loci (qtl) approach, we explore the genetic architecture of resistance in the crustacean daphnia magna to two of its natural parasites: the horizontally transmitted bacterium p ... | 2015 | 25335558 |
| the development of pathogen resistance in daphnia magna: implications for disease spread in age-structured populations. | immunity in vertebrates is well established to develop with time, but the ontogeny of defence in invertebrates is markedly less studied. yet, age-specific capacity for defence against pathogens, coupled with age structure in populations, has widespread implications for disease spread. thus, we sought to determine the susceptibility of hosts of different ages in an experimental invertebrate host-pathogen system. in a series of experiments, we show that the ability of daphnia magna to resist its n ... | 2014 | 25214486 |
| starvation reveals the cause of infection-induced castration and gigantism. | parasites often induce life-history changes in their hosts. in many cases, these infection-induced life-history changes are driven by changes in the pattern of energy allocation and utilization within the host. because these processes will affect both host and parasite fitness, it can be challenging to determine who benefits from them. determining the causes and consequences of infection-induced life-history changes requires the ability to experimentally manipulate life history and a framework f ... | 2014 | 25143034 |
| effects of juvenile host density and food availability on adult immune response, parasite resistance and virulence in a daphnia-parasite system. | host density can increase infection rates and reduce host fitness as increasing population density enhances the risk of becoming infected either through increased encounter rate or because host condition may decline. conceivably, potential hosts could take high host density as a cue to up-regulate their defence systems. however, as host density usually covaries with food availability, it is difficult to examine the importance of host density in isolation. thus, we performed two full-factorial ex ... | 2014 | 24736707 |
| dietary supply with polyunsaturated fatty acids and resulting maternal effects influence host--parasite interactions. | interactions between hosts and parasites can be substantially modulated by host nutrition. polyunsaturated fatty acids (pufas) are essential dietary nutrients; they are indispensable as structural components of cell membranes and as precursors for eicosanoids, signalling molecules which act on reproduction and immunity. here, we explored the potential of dietary pufas to affect the course of parasitic infections using a well-established invertebrate host - parasite system, the freshwater herbivo ... | 2013 | 24175981 |
| cross-species infection trials reveal cryptic parasite varieties and a putative polymorphism shared among host species. | a parasite's host range can have important consequences for ecological and evolutionary processes but can be difficult to infer. successful infection depends on the outcome of multiple steps and only some steps of the infection process may be critical in determining a parasites host range. to test this hypothesis, we investigated the host range of the bacterium pasteuria ramosa, a daphnia parasite, and determined the parasites success in different stages of the infection process. multiple genoty ... | 2014 | 24116675 |
| a matching-allele model explains host resistance to parasites. | the maintenance of genetic variation and sex despite its costs has long puzzled biologists. a popular idea, the red queen theory, is that under rapid antagonistic coevolution between hosts and their parasites, the formation of new rare host genotypes through sex can be advantageous as it creates host genotypes to which the prevailing parasite is not adapted. for host-parasite coevolution to lead to an ongoing advantage for rare genotypes, parasites should infect specific host genotypes and hosts ... | 2013 | 23707426 |
| the expression and evolution of virulence in multiple infections: the role of specificity, relative virulence and relative dose. | multiple infections of the same host by different strains of the same microparasite species are believed to play a crucial role during the evolution of parasite virulence. we investigated the role of specificity, relative virulence and relative dose in determining the competitive outcome of multiple infections in the daphnia magna-pasteuria ramosa host-parasite system. | 2013 | 23641899 |
| gene expression profiling of three different stressors in the water flea daphnia magna. | microarrays are an ideal tool to screen for differences in gene expression of thousands of genes simultaneously. however, often commercial arrays are not available. in this study, we performed microarray analyses to evaluate patterns of gene transcription following exposure to two natural and one anthropogenic stressor. cdna microarrays compiled of three life stage specific and three stressor-specific est libraries, yielding 1734 different est sequences, were used. we exposed juveniles of the wa ... | 2013 | 23564370 |
| interactive effects of a bacterial parasite and the insecticide carbaryl to life-history and physiology of two daphnia magna clones differing in carbaryl sensitivity. | natural and chemical stressors occur simultaneously in the aquatic environment. their combined effects on biota are usually difficult to predict from their individual effects due to interactions between the different stressors. several recent studies have suggested that synergistic effects of multiple stressors on organisms may be more common at high compared to low overall levels of stress. in this study, we used a three-way full factorial design to investigate whether interactive effects betwe ... | 2013 | 23411351 |
| host nutrition alters the variance in parasite transmission potential. | the environmental conditions experienced by hosts are known to affect their mean parasite transmission potential. how different conditions may affect the variance of transmission potential has received less attention, but is an important question for disease management, especially if specific ecological contexts are more likely to foster a few extremely infectious hosts. using the obligate-killing bacterium pasteuria ramosa and its crustacean host daphnia magna, we analysed how host nutrition af ... | 2013 | 23407498 |
| sex-specific effects of a parasite evolving in a female-biased host population. | males and females differ in many ways and might present different opportunities and challenges to their parasites. in the same way that parasites adapt to the most common host type, they may adapt to the characteristics of the host sex they encounter most often. to explore this hypothesis, we characterized host sex-specific effects of the parasite pasteuria ramosa, a bacterium evolving in naturally, strongly, female-biased populations of its host daphnia magna. | 2012 | 23249484 |
| the cellular immune response of daphnia magna under host-parasite genetic variation and variation in initial dose. | in invertebrate-parasite systems, the likelihood of infection following parasite exposure is often dependent on the specific combination of host and parasite genotypes (termed genetic specificity). genetic specificity can maintain diversity in host and parasite populations and is a major component of the red queen hypothesis. however, invertebrate immune systems are thought to only distinguish between broad classes of parasite. using a natural host-parasite system with a well-established pattern ... | 2012 | 23025616 |