| [proboscis worm, echinorhynchus gadi (zoega) from a relict cod of lake mogil'noye]. | data on the extensiveness and intensity of infection of kildin island cod with echinorhynchus gadi in various seasons are given. e. gadi was proved to have a one-year life cycle and gammarus duebeni as an intermediate host in the lake. a change of the parasite generations occurs in late summer--autumn. a high extensiveness (100%) and intensity of kildin cod infection with e. gadi depends on the feeding habits (monophagy) and narrow distribution range of the host. infection intensity is directly ... | 1977 | 142953 |
| horizontal transfer of parasitic sex ratio distorters between crustacean hosts. | parasitic sex distorters were artificially transferred within and between crustacean host species in order to study the effects of parasitism on host fitness and sex determination and to investigate parasite host specificity. implantation of nosema sp. to uninfected strains of its gammarus duebeni host resulted in an active parasite infection in the gonad of recipient females and subsequent transovarial parasite transmission. the young of artificially infected females were feminized by the paras ... | 1998 | 9695096 |
| ultrastructural characterisation and molecular taxonomic identification of nosema granulosis n. sp., a transovarially transmitted feminising (ttf) microsporidium. | a novel microsporidian parasite is described, which infects the crustacean host gammarus duebeni. the parasite was transovarially transmitted and feminised host offspring. the life cycle was monomorphic with three stages. meronts were found in host embryos, juveniles, and in the gonadal tissue of adults. sporoblasts and spores were restricted to the gonad. sporogony was disporoblastic giving rise to paired sporoblasts, which then differentiated to form spores. spores were not found in regular gr ... | 1999 | 10519217 |
| incomplete feminisation by the microsporidian sex ratio distorter, nosema granulosis, and reduced transmission and feminisation efficiency at low temperatures. | we investigated the effects of temperature on transovarial transmission and feminisation by nosema granulosis, a microsporidian sex ratio distorter of the brackish water amphipod gammarus duebeni. there was no difference in parasite transmission efficiency to the f(1) eggs of infected females maintained under two temperature conditions, 5 and 10 degrees c (89 and 86%, respectively). when f(1) individuals were screened as adults, the proportion infected was also similar at both temperatures (74 a ... | 2002 | 12062553 |
| infection of gammarus duebeni populations by two vertically transmitted microsporidia; parasite detection and discrimination by pcr-rflp. | we screened a population of the brackish water crustacean gammarus duebeni from the isle of cumbrae for the presence of vertically transmitted microsporidia. we compared 2 screening techniques; light microscopy and pcr-based detection using generic 16s rdna microsporidian primers. fifty percent of females from this population tested positive for vertically transmitted microsporidia. the pcr screen was 100% efficient in comparison with existing lm based screening. in addition, the pcr screen prod ... | 2002 | 12166521 |
| the impact of a vertically transmitted microsporidian, nosema granulosis on the fitness of its gammarus duebeni host under stressful environmental conditions. | although purely vertically transmitted parasites are predicted to cause low pathogenicity in their hosts, the effects of such parasites on host fitness under stressful environmental conditions have not previously been assessed. here, we investigate the effects of nosema granulosis, a vertically transmitted, microsporidian parasite of the brackish water amphipod gammarus duebeni, on host growth and survival under conditions of host-host competition and limited food. the parasite had no effect on ... | 2003 | 12636349 |
| parasite-mediated predation between native and invasive amphipods. | parasites can structure biological communities directly through population regulation and indirectly by processes such as apparent competition. however, the role of parasites in the process of biological invasion is less well understood and mechanisms of parasite mediation of predation among hosts are unclear. mutual predation between native and invading species is an important factor in determining the outcome of invasions in freshwater amphipod communities. here, we show that parasites mediate ... | 2003 | 12816645 |
| parasite transmission and cannibalism in an amphipod (crustacea). | in its freshwater amphipod host gammarus duebeni celticus, the microsporidian parasite pleistophora mulleri showed 23% transmission efficiency when uninfected individuals were fed infected tissue, but 0% transmission by water-borne and coprophagous routes. cannibalism between unparasitised and parasitised individuals was significantly in favour of the former (37% compared to 0%). in addition, cannibalism between parasitised individuals was significantly higher than between unparasitised individu ... | 2003 | 12865079 |
| two species of feminizing microsporidian parasite coexist in populations of gammarus duebeni. | the amphipod crustacean gammarus duebeni hosts two species of vertically transmitted microsporidian parasites, nosema granulosis and microsporidium sp. a. here it is demonstrated that these co-occurring parasite species both cause infected females to produce female-biased broods. a survey of european g. duebeni populations demonstrates that these two parasites co-occur in six of 10 populations. these findings contrast with the theoretical prediction that two vertically transmitted feminizing par ... | 2003 | 14635846 |
| association with host mitochondrial haplotypes suggests that feminizing microsporidia lack horizontal transmission. | the amphipod crustacean gammarus duebeni hosts two feminizing microsporidian parasites, nosema granulosis and microsporidium sp. samples of g. duebeni were collected from three sites on the scottish island of great cumbrae and screened for microsporidia using polymerase chain reaction. associations between the prevalence of the two feminizing parasites and haplotypes of the host mitochondrial gene cytochrome oxidase i (coi) were investigated. the prevalence of both parasites varied significantly ... | 2003 | 14640399 |
| mechanisms of parasite-induced sex reversal in gammarus duebeni. | the amphipod gammarus duebeni is host to the feminising microsporidian parasite nosema granulosis that converts males into functional females. to test the hypothesis that the parasite acts through endocrine disruption we compared the morphology of the gonad and activity of the androgenic gland, which coordinates male sexual differentiation, in infected and uninfected animals. male gonad consisted of testis, seminal vesicle and vas deferens that was anchored to the genital papilla on segment 7. t ... | 2004 | 15111096 |
| resolution of a taxonomic conundrum: an ultrastructural and molecular description of the life cycle of pleistophora mulleri (pfeiffer 1895; georgevitch 1929). | the classification of a microsporidian parasite observed in the abdominal muscles of amphipod hosts has been repeatedly revised but still remains inconclusive. this parasite has variable spore numbers within a sporophorous vesicle and has been assigned to the genera glugea, pleistophora, stempellia, and thelohania. we used electron microscopy and molecular evidence to resolve the previous taxonomic confusion and confirm its identification as pleistophora mulleri. the life cycle of p. mulleri is ... | 2003 | 15132170 |
| lethal and sublethal toxicity of ammonia to native, invasive, and parasitised freshwater amphipods. | in lethal and sublethal ammonia toxicity tests, we examined differences in tolerance of three species of freshwater amphipods, one native and two invasive in ireland. the native gammarus duebeni celticus was slightly less tolerant to ammonia than the invasive g. pulex (96 h lc50= 1.155 and 1.544 mg l(-1), respectively), while another invader, crangonyx pseudogracilis, had the lowest tolerance (lc50= 0.36 mg l(-1)). parasitism of g. pulex by the acanthocephalan echinorhynchus truttae greatly redu ... | 2004 | 15223278 |
| local adaptation and enhanced virulence of nosema granulosis artificially introduced into novel populations of its crustacean host, gammarus duebeni. | local adaptation theory predicts that, on average, most parasite species should be locally adapted to their hosts (more suited to hosts from local than distant populations). local adaptation has been studied for many horizontally transmitted parasites, however, vertically transmitted parasites have received little attention. here we present the first study of local adaptation in an animal/parasite system where the parasite is vertically transmitted. we investigate local adaptation and patterns o ... | 2005 | 15722078 |
| ecological impacts of the microsporidian parasite pleistophora mulleri on its freshwater amphipod host gammarus duebeni celticus. | the microsporidian parasite, pleistophora mulleri, infects the abdominal muscle of the freshwater amphipod gammarus duebeni celticus. we recently showed that p. mulleri infection was associated with g. d. celticus hosts being more vulnerable to predation by the invasive amphipod gammarus pulex. parasitized g. d. celticus also had a reduced ability to prey upon other co-occurring amphipods. we suggested the parasite may have pervasive influences on host ecology and behaviour. here, we examine the ... | 2005 | 16178354 |
| transmission and burden and the impact of temperature on two species of vertically transmitted microsporidia. | microsporidia are unusual amongst eukaryotic parasites in that they utilize both vertical and horizontal transmission and vertically transmitted species can cause sex ratio distortion in their host. here we study vertical transmission in two species of feminising microsporidia, nosema granulosis and dictyocoela duebenum, infecting a single population of the crustacean host gammarus duebeni and measure the effect of temperature on parasite transmission and replication. n. granulosis was verticall ... | 2006 | 16442539 |
| targeting of host cell lineages by vertically transmitted, feminising microsporidia. | feminising microsporidian parasites are transmitted vertically from generation to generation of their crustacean hosts. little is known about the mechanisms underpinning vertical transmission, in particular, parasite transmission to the host gonad during host development. here, we investigate the burden and distribution of two species of vertically transmitted, feminising microsporidia (dictyocoela duebenum and nosema granulosis) during early embryogenesis (zygote to eight-cells) of the gammarus ... | 2006 | 16696983 |
| strategic sperm allocation under parasitic sex-ratio distortion. | parasitic sex-ratio distorters are a major selective force in the evolution of host mating behaviour and mate choice. here, we investigate sperm limitation in the amphipod gammarus duebeni and the impact of the microsporidian sex-ratio distorter nosema granulosis on sperm allocation strategies. we show that males become sperm limited after three consecutive matings and provide uninfected, high fecundity, females with more sperm than infected females. we show that sperm limitation leads to a decr ... | 2006 | 17148331 |
| infection by a vertically-transmitted microsporidian parasite is associated with a female-biased sex ratio and survival advantage in the amphipod gammarus roeseli. | summaryvertically transmitted parasites may have positive, neutral or negative effects on host fitness, and are also predicted to exhibit sex-specific virulence to increase the proportion or fitness of the transmitting sex. we investigated these predictions in a study on the survival and sex ratio of offspring of the amphipod gammarus roeseli from females infected by the vertically transmitted microsporidia nosema granulosis. we found, to our knowledge, the first evidence for a positive relation ... | 2007 | 17445328 |
| distribution and host range of the microsporidian pleistophora mulleri. | microsporidia of the genus pleistophora are important parasites of fish and crustacea. pleistophora mulleri has been described previously as a parasite of the gammarid amphipod crustacean gammarus duebeni celticus in irish freshwater habitats. through a survey of european g. duebeni populations, p. mulleri was found to be widely distributed in the western british isles (wales, scotland, and the isle of man), and populations of the subspecies gammarus duebeni duebeni as well as g. d. celticus wer ... | 2008 | 18681850 |
| molecular characterisation of the microsporidia of the amphipod gammarus duebeni across its natural range revealed hidden diversity, wide-ranging prevalence and potential for co-evolution. | microsporidia comprise an unusual group of intracellular, eukaryotic parasites that exhibit ubiquitous distribution throughout the animal kingdom. we analysed the small subunit ribosomal gene (ssurdna) using pcr and sequencing and screened 894 gammarus duebeni (crustacea, amphipoda) specimens from 35 european marine and freshwater populations. we discovered considerable hidden microsporidian diversity. blast searches, sequence analysis and phylogenetic analysis revealed intraspecific sequence va ... | 2010 | 20601176 |
| microsporidian parasites feminise hosts without paramyxean co-infection: support for convergent evolution of parasitic feminisation. | feminisation of amphipod crustaceans is associated with the presence of at least three microsporidian parasites and one paramyxean parasite, suggesting that the ability to feminise has evolved multiple times in parasites of amphipods. co-infection by a paramyxean with one of the putative microsporidian feminisers, dictyocoela duebenum, has inspired the alternative hypothesis that all feminisation of amphipods is caused by paramyxea and that all microsporidian associations with feminisation are d ... | 2015 | 25747725 |
| (cryptic) sex in the microsporidian nosema granulosis--evidence from parasite rdna and host mitochondrial dna. | microsporidia are single-celled, intracellular eukaryotes that parasitise a wide range of animals. the nosema/vairimorpha group includes some putative asexual species, and asexuality is proposed to have originated multiple times from sexual ancestors. here, we studied the variation in the ribosomal dna (rdna) of 14 isolates of the presumed apomictic and vertically transmitted nosema granulosis to evaluate its sexual status. the analysed dna fragment contained a part of the small-subunit ribosoma ... | 2014 | 24269340 |
| effects of feminizing microsporidia on the masculinizing function of the androgenic gland in gammarus duebeni. | feminizing parasites enhance their vertical transmission to the host offspring by converting genetic male hosts into phenotypic females. crustacea are the only invertebrates where sexual differentiation is controlled by a specialised endocrine organ, the androgenic gland, rather than by the gonads. we showed that a feminizing microsporidian microsporidium sp. inhibits androgenic gland differentiation. we investigated the effect of microsporidium sp. and a second feminizing microsporidium, nosema ... | 2013 | 23207223 |
| eaten alive: cannibalism is enhanced by parasites. | cannibalism is ubiquitous in nature and especially pervasive in consumers with stage-specific resource utilization in resource-limited environments. cannibalism is thus influential in the structure and functioning of biological communities. parasites are also pervasive in nature and, we hypothesize, might affect cannibalism since infection can alter host foraging behaviour. we investigated the effects of a common parasite, the microsporidian pleistophora mulleri, on the cannibalism rate of its h ... | 2015 | 26064614 |
| the enemy of my enemy is my friend: intraguild predation between invaders and natives facilitates coexistence with shared invasive prey. | understanding and predicting the outcomes of biological invasions is challenging where multiple invader and native species interact. we hypothesize that antagonistic interactions between invaders and natives could divert their impact on subsequent invasive species, thus facilitating coexistence. from field data, we found that, when existing together in freshwater sites, the native amphipod gammarus duebeni celticus and a previous invader g. pulex appear to facilitate the establishment of a secon ... | 2014 | 25122739 |
| evolution of mitochondrial genomes in baikalian amphipods. | amphipods (crustacea) of lake baikal are a very numerous and diverse group of invertebrates generally believed to have originated by adaptive radiation. the evolutionary history and phylogenetic relationships in baikalian amphipods still remain poorly understood. sequencing of mitochondrial genomes is a relatively feasible way for obtaining a set of gene sequences suitable for robust phylogenetic inferences. the architecture of mitochondrial genomes also may provide additional information on the ... | 2016 | 28105939 |
| predicting invasive species impacts: a community module functional response approach reveals context dependencies. | predatory functional responses play integral roles in predator-prey dynamics, and their assessment promises greater understanding and prediction of the predatory impacts of invasive species. other interspecific interactions, however, such as parasitism and higher-order predation, have the potential to modify predator-prey interactions and thus the predictive capability of the comparative functional response approach. we used a four-species community module (higher-order predator; focal native or ... | 2015 | 25265905 |
| biochemical markers of pollutant responses in macrozoobenthos from the white sea: intracellular proteolysis. | coastal environments of kandalaksha gulf in the white sea (russia) despite nature conservation efforts are heavily influenced by human activities. biological effects of complex environmental pollution, including organic substances, heavy metals, and oil hydrocarbons, were assessed in widely distributed marine invertebrates, gammarus duebeni (crustacea, amphipoda) and mytilus edulis (mollusca, bivalvia), collected from a series of anthropogenically-impacted areas and distanced reference sites in ... | 2014 | 24559608 |
| specific detection and localization of microsporidian parasites in invertebrate hosts by using in situ hybridization. | we designed fluorescence in situ hybridization probes for two distinct microsporidian clades and demonstrated their application in detecting, respectively, nosema/vairimorpha and dictyoceola species. we used them to study the vertical transmission of two microsporidia infecting the amphipod gammarus duebeni. | 2013 | 23087031 |
| the mitogenome of gammarus duebeni (crustacea amphipoda): a new gene order and non-neutral sequence evolution of tandem repeats in the control region. | we determined the complete mitogenome sequence of gammarus duebeni (peracarida, amphipoda). the mitogenome is circular and has a length of 15,651bp. the content corresponds to typical mitogenomes of metazoans. the gene order and transcriptional polarity of the protein-coding genes is identical to the pancrustacean ground pattern. six trna genes are rearranged, making the gene order unique. thus it will bring forward the understanding of mitogenome evolution within the peracarida, for which much ... | 2012 | 22437035 |
| congeneric amphipods show differing abilities to maintain metabolic rates with latitude. | metabolic variability across latitudinal populations of gammarid amphipods was examined in the summer by determining whole-animal rates of oxygen uptake (m(o)₂) in four species with overlapping distribution patterns in the northeast atlantic and arctic oceans. comparisons were made between an arctic/boreal species, gammarus setosus, a subarctic/boreal species, gammarus oceanicus, a boreal/temperate species, gammarus duebeni duebeni, and a temperate species, gammarus locusta. measurements include ... | 2013 | 21460526 |
| glacial-driven vicariance in the amphipod gammarus duebeni. | we have examined the genetic diversity using mitochondrial coi and nd2 sequence data from 306 specimens of the amphi-atlantic-distributed amphipod gammarus duebeni. marine populations from the atlantic ocean, the baltic and north sea, as well as freshwater populations from ireland, cornwall and brittany were analysed. g. duebeni is a complex of five allopatric lineages. freshwater populations result from multiple invasions of marine ancestors, represented by distinct lineages. we interpret the r ... | 2010 | 19654046 |
| phylogeography and environmental diversification of a highly adaptable marine amphipod, gammarus duebeni. | genetic diversity and phylogeographic population structure in the gammarid amphipod, gammarus duebeni, were investigated across its broad latitudinal distribution in the ne and nw atlantic by analysis of mitochondrial dna sequence. gammarus duebeni has exceptional tolerance of salinity change and inhabits environments ranging from marine to freshwater. the longstanding debate on whether there are distinct marine and freshwater subspecies was assessed by sampling populations from sites characteri ... | 2007 | 17426729 |
| coexistence of three microsporidia parasites in populations of the freshwater amphipod gammarus roeseli: evidence for vertical transmission and positive effect on reproduction. | we investigated the prevalence, transmission mode and fitness effects of infections by obligatory intracellular, microsporidian parasites in the freshwater amphipod gammarus roeseli. we found three different microsporidia species in this host, all using transovarial (vertical) transmission. all three coexist at different prevalences in two host populations, but bi-infected individuals were rarely found, suggesting no (or very little) horizontal transmission. it is predicted that vertically-trans ... | 2004 | 15380685 |
| the validity of the gammarus:asellus ratio as an index of organic pollution: abiotic and biotic influences. | in freshwaters. gammarus spp. are more sensitive to organic pollution than asellus spp. and the relative abundance of the two taxa has been proposed as a pollution index. we tested the validity of this by examining the relationship between the gammarus: asellus (g : a) ratio and (1) a suite of physico-chemical variables. (2) established biotic (average score per taxon, aspt) and richness (species richness (s) and ephemeroptera, plecoptera and trichoptera families richness (ept family richness)) ... | 2002 | 11767742 |
| invading predatory crustacean dikerogammarus villosus eliminates both native and exotic species. | as the tempo of biological invasions increases, explanations and predictions of their impacts become more crucial. particularly with regard to biodiversity, we require elucidation of interspecific behavioural interactions among invaders and natives. in freshwaters in the netherlands, we show that the invasive ponto-caspian crustacean amphipod dikerogammarus villosus is rapidly eliminating gammarus duebeni, a native european amphipod, and gammarus tigrinus, until now a spectacularly successful in ... | 2000 | 10874746 |
| within-host transmission strategies of transovarial, feminizing parasites of gammarus duebeni. | the amphipod gammarus duebeni harbours several species of vertically transmitted microsporidian parasites. g. duebeni were collected from 3 localities in the uk. animals from budle bay, northumberland, were infected with octosporea effeminans, and those from millport, isle of cumbrae and fenham flats, northumberland were infected with microsporidia of the genus nosema. we derived expected distributions of parasites per host embryonic cell by modelling parasite transmission as a multitype, galton ... | 1998 | 9695097 |
| size and pairing success in gammarus duebeni: can females be too big? | the crustacean gammarus duebeni exhibits precopula mate guarding and size-assortative pairing, in which larger males tend to pair with larger females. size-assortative pairing may result from sexual selection or natural selection (mechanical or loading constraints limiting the size of female that can be carried by the male). if loading constraints are important, large females should have lower pairing success than females of intermediate size as they will be less likely to encounter sufficiently ... | 1997 | 9398383 |
| the effect of salinity on transovarial transmission of a microsporidian infecting gammarus duebeni. | this is an investigation of the impact of salinity on transovarial transmission and burden of a microsporidian sex ratio distorter in the inter-tidal crustacean gammarus duebeni. exposure of parasitized mothers to increased salinity during the gonotrophic cycle caused an increase in parasite burden in the follicle cells and a decrease in burden in the oocytes. it appears that salinity impedes parasite transmission from the follicle cells to the oocytes during host oogenesis. a lower proportion o ... | 1997 | 9364564 |
| cellular distribution of a feminizing microsporidian parasite: a strategy for transovarial transmission. | the cellular distribution of a vertically transmitted, feminizing microsporidian was followed in its host gammarus duebeni. in adult females the parasite was restricted to gonadal tissue, in particular primary and secondary follicle cells. spores were diplokaryotic with a thin spore wall and a short polar filament, characteristics typical of 'early' spores involved in autoinfection. the diplokaryotic life-cycle, absence of spore groupings and of a pansporoblast membrane typify the genus nosema. ... | 1997 | 10190171 |
| soluble protein changes in pollution-adapted gammarus duebeni. | | 1995 | 7672400 |
| microtubule systems associated with the septate junctions of the gill cells of four gammarid amphipods. | the microtubular systems associated with the septate junctions of the gill epithelial cells of four species of gammarid amphipod are described. the four species examined included two relatively stenohaline marine forms, chaetogammarus marinus and gammarus locusta; a highly euryhaline species, gammarus duebeni, and a stenohaline freshwater species, gammarus pulex. of these amphipods, g. locusta and c. marinus maintain only a limited osmotic gradient between their haemolymph and the medium and hav ... | 1995 | 18621295 |
| structural changes in the gill cells of gammarus duebeni (crustacea, amphipoda) under osmotic stress; with notes on microtubules in association with the septate junctions. | the amphipod crustacean gammarus duebeni (lilljeborg) tolerates salinities in the range freshwater to seawater. such tolerance requires the ability to respond to the varying degrees of osmotic stress imposed on the single layer of epithelial cells separating the outside medium from the haemolymph space in the gills. following transfer of individuals from low salinities to seawater, changes occur in the fine structure of the epithelial cells. these changes involve the configuration of the apical ... | 1994 | 18621289 |
| diuresis in the amphipod gammarus duebeni induced by methylmercury, d.d.t., lindane and fenithrothion. | | 1975 | 56253 |
| regulation of water and some ions in gammarids (amphipods). i. gammarus duebeni lilljeborg from brackish water and fresh water. | | 1971 | 5114026 |
| sodium influx and loss in freshwater and brackish-water populations of the amphipod gammarus duebeni lilljeborg. | | 1971 | 5549767 |
| the involvement of sodium transport in the volume regulation of the amphipod crustacean, gammarus duebeni. | | 1970 | 5487175 |
| experimental populations of gammarus duebeni in fresh water with a low sodium content. | | 1970 | 16058734 |
| irish and french fresh water populations of gammarus duebeni subspecifically different from brackish water populations. | | 1970 | 16058733 |
| pheromone transport and reception in an amphipod. | sexual dimorphism in the second antennae of the amphipod gammarus duebeni lilljeborg is connected with the reception in the male of a female sex pheromone transported through the water. investigations on tritium-labeled specimens were carried out with scintillator and autoradiographic techniques. | 1970 | 17776340 |
| infection by the microsporidian octosporea effeminans sp. n., and its sex determining influence in the amphipod gammarus duebeni. | | 1968 | 4967337 |
| [photoperiodic influence of the sex ratio in gammarus duebeni (crustacea, amphipoda)]. | | 1966 | 5993013 |
| activation of the sodium uptake system at high blood concentrations in the amphipod gammarus duebeni. | | 1964 | 14187303 |