| population development of pasteuria penetrans on meloidogyne arenaria. | a microplot study on the influence of cropping sequences with peanut in summer and bare fallowed or cover crops of rye or vetch in winter on the population development of pasteuria penetrans was initiated in the spring of 1987. the number of spores of p. penetrans attached per second-stage juvenile of meloidogyne arenaria race 1 increased from 0.11 in the fall of 1987 to 7.6, 8.6, and 3.6 in the fall of 1989 in the rye, vetch, and fallowed plots, respectively. higher (p </= 0.05) levels of p. pe ... | 1991 | 19283094 |
| specific gravity of spores of pasteuria penetrans and extraction of spore-filled nematodes from soil. | the specific gravity of spores of pasteuria penetrans collected from meloidogyne arenaria was found to be around 1.28. increasing the sucrose concentration used for the extraction of pratylenchus scribneri from a specific gravity of 1.14 to 1.26 led to the recovery of higher numbers of specimens filled with spores of pasteuria sp. (p </= 0.05). the numbers of spore-filled specimens of hoplolaimus galeatus recovered from field soil were not affected by the concentration of the sucrose solutions. ... | 1991 | 19283193 |
| parasitism of helicotylenchus lobus by pasteuria penetrans in naturally infested soil. | the population density of helicotylenchus lobus and the percentage of the population with spores of pasteuria penetrans were determined for 10 monthly intervals in naturally infested turf grass soil at riverside, california. the percentage of nematodes with attached spores ranged from 40% to 67%. no relationship was found between nematode density and the percentage of nematodes with spores. the mean and maximum numbers of spores adhering per nematode with at least one spore ranged from 2 to 8 an ... | 1992 | 19283198 |
| pasteuria sp. parasitizing trophonema okamotoi in florida. | two populations of trophonema okamotoi parasitized by pasteuria sp. were found on liquidambar styraciflua (sweetgum) and on an unidentified tropical grass in north-central florida. endospores of this pasteuria sp. attached to motile vermiform second-stage juveniles (j2) and males of t. okamotoi, but not to other developmental stages. sporangia and new endospores were produced only inside the bodies of swollen and sedentary third- and fourth-stage juveniles and females that developed in the host ... | 1992 | 19283199 |
| parasitism of the citrus nematode, tylenchulus semipenetrans, by pasteuria penetrans in iraq. | | 1989 | 19287633 |
| host range and ecology of isolates of pasteuria spp. from the southeastern united states. | isolates of pasteuria penetrans were evaluated for ecological characteristics that are important in determining their potential as biological control agents. isolate p-20 survived without loss of its ability to attach to its host nematode in dry, moist, and wet soil and in soil wetted and dried repeatedly for 6 weeks. some spores moved 6.4 cm (the maximum distance tested) downward in soil within 3 days with percolating water. the isolates varied greatly in their attachment to different nematode ... | 1990 | 19287753 |
| antagonists of plant-parasitic nematodes in florida citrus. | in a survey of antagonists of nematodes in 27 citrus groves, each with a history of tylenchulus semipenetrans infestation, and 17 noncitrus habitats in florida, approximately 24 species of microbial antagonists capable of attacking vermiform stages of radopholus citrophilus were recovered. eleven of these microbes and a species of pasteuria also were observed attacking vermiform stages of t. semipenetrans. verticillium chlamydosporium, paecilomyces lilacinus, p. marquandii, streptomyces sp., art ... | 1990 | 19287759 |
| isolates of the pasteuria penetrans group from phytoparasitic nematodes in bermudagrass turf. | a survey was conducted between 1985 and 1989 of isolates of the pasteuria penetrans group on phytoparasitic nematodes in bermudagrass (cynodon spp.) turf in southern florida. six different isolates of the p. penetrans group were observed from five different species of phytoparasitic nematode hosts. five of the bacterial isolates were different (p </= 0.01) in sporangium diameter, endospore width, and ratio of sporangium diameter to endospore width. all locations surveyed had one or more isolates ... | 1990 | 19287792 |
| understanding the interaction between an obligate hyperparasitic bacterium, pasteuria penetrans and its obligate plant-parasitic nematode host, meloidogyne spp. | pasteuria penetrans is an endospore-forming bacterium, which is a hyperparasite of root-knot nematodes meloidogyne spp. that are economically important pests of a wide range of crops. the life cycle of the bacterium and nematode are described with emphasis on the bacterium's potential as a biocontrol agent. two aspects that currently prohibit the commercial development of the bacterium as a biocontrol agent are the inability to culture it outside its host and its host specificity. vegetative gro ... | 2009 | 19289196 |
| biological control of meloidogyne incognita by paecilomyces lilacinus and pasteuria penetrans. | the root-knot nematode meloidogyne incognita was controlled more effectively and yields of host plants were greater when paecilomyces lilacinus and pasteuria penetrans were applied together in field microplots than when either was applied alone. yields of winter vetch from microplots inoculated with the nematode and with both organisms were not statistically different from yields from uninoculated control plots. | 1987 | 19290133 |
| biocontrol: bacillus penetrans and related parasites of nematodes. | bacillus penetrans mankau, 1975, previously described as duboscqia penetrans thorne 1940, is a candidate agent for biocontrol of nematodes. this review considers the life stages of this bacterium: vegetative growth phase, colony fragmentation, sporogenesis, soil phase, spore attachment, and penetration into larvae of root-knot nematodes. the morphology of the microthallus colonies and the unusual external features of the spore are discussed. taxonomic affinities with the actinomycetes, particula ... | 1980 | 19300701 |
| an ancient immunity gene duplication in daphnia magna: rna expression and sequence analysis of two nitric oxide synthase genes. | no (nitric oxide) is a highly reactive free radical gas thought to play a major role in the invertebrate immune response by harming pathogens and limiting their growth. here we report on studies of nitric oxide synthase (nos) genes in the crustacean daphnia, one of the few non-insect arthropod models used to study host-pathogen interactions. while the nos gene is found as a single copy in other invertebrates, we found two copies (nos1 and nos2), which a phylogenetic reconstruction showed to be t ... | 2009 | 19416737 |
| measuring parasite fitness under genetic and thermal variation. | accurate measures of parasite fitness are essential to study host-parasite evolution. parasite fitness depends on several traits involved in establishing infection, growth and transmission. individually, these traits provide a reasonable approximation of fitness, but they may also be under the shared control of both host and parasite genetics (g(h) x g(p) interactions), or be differentially sensitive to environmental variation. using the natural host-parasite system daphnia magna-pasteuria ramos ... | 2009 | 19455181 |
| detection of pasteuria penetrans infection in meloidogyne arenaria race 1 in planta by polymerase chain reaction. | we report on the development of a pcr-based assay to detect pasteuria penetrans infection of meloidogyne arenaria in planta using specific primers for recently sequenced sige, spoiiab and atpf genes of p. penetrans biotype p20. amplification of these genes in crude dna extracts of ground tomato root galls using real-time kinetic pcr distinguished infected from uninfected m. arenaria race 1 by analysis of consensus thresholds for single copy genes. fluorescent in situ hybridization (fish) using t ... | 2004 | 19712314 |
| environmental quantification of pasteuria penetrans endospores using in situ antigen extraction and immunodetection with a monoclonal antibody. | abstract pasteuria penetrans is an obligate parasite of root-knot nematodes (meloidogyne spp.) that has attracted significant attention as a promising biocontrol agent. the inability to culture p. penetrans has invoked the need for a quantitative detection capability to facilitate biocontrol studies. a chemical extraction method using urea, dithiothreitol and ches buffer (udc) is shown to release soluble endospore envelope antigen from endospores present in complex matrices, generating an extrac ... | 2003 | 19719647 |
| identification of a polymorphic collagen-like protein in the crustacean bacteria pasteuria ramosa. | pasteuria ramosa is a spore-forming bacterium that infects daphnia species. previous results demonstrated a high specificity of host clone/parasite genotype interactions. surface proteins of bacteria often play an important role in attachment to host cells prior to infection. we analyzed surface proteins of p. ramosa spores by two-dimensional gel electrophoresis. for the first time, we prove that two isolates selected for their differences in infectivity reveal few but clear-cut differences in p ... | 2009 | 19770039 |
| exploring the molecular landscape of host-parasite coevolution. | host-parasite coevolution is a dynamic process that can be studied at the phenotypic, genetic, and molecular levels. although much of what we currently know about coevolution has been learned through phenotypic measures, recent advances in molecular techniques have provided tools to greatly deepen this research. both the availability of full-genome sequences and the increasing feasibility of high-throughput gene expression profiling are leading to the discovery of genes that have a key role in a ... | 2009 | 19843595 |
| pathogen dose infectivity curves as a method to analyze the distribution of host susceptibility: a quantitative assessment of maternal effects after food stress and pathogen exposure. | stress conditions have been found to change the susceptibility of hosts or their offspring to infection. the usual method of testing at just one parasite dose level does not allow conclusions on the distribution of susceptibility. to better understand the epidemiology and evolution of host-parasite systems, however, knowledge about the distribution of host susceptibility, the parameters that characterize it, and how it changes in response to environmental conditions is required. we investigated ... | 2010 | 19911987 |
| transgenerational effects of poor elemental food quality on daphnia magna. | environmental effects on parents can strongly affect the phenotype of their offspring, which alters the heritability of traits and the offspring's responses to the environment. we examined whether p limitation of the aquatic invertebrate, daphnia magna, alters the responses of its offspring to inadequate p nutrition. mother daphnia consuming p-poor algal food produced smaller neonates having lower body p content compared to control (p-rich) mothers. these offspring from p-stressed mothers, when ... | 2010 | 19957090 |
| a method for release and multiple strand amplification of small quantities of dna from endospores of the fastidious bacterium pasteuria penetrans. | to establish a reliable protocol to extract dna from pasteuria penetrans endospores for use as template in multiple strand amplification, thus providing sufficient material for genetic analyses. to develop a highly sensitive pcr-based diagnostic tool for p. penetrans. | 2010 | 20302597 |
| genetic variation in the cellular response of daphnia magna (crustacea: cladocera) to its bacterial parasite. | linking measures of immune function with infection, and ultimately, host and parasite fitness is a major goal in the field of ecological immunology. in this study, we tested for the presence and timing of a cellular immune response in the crustacean daphnia magna following exposure to its sterilizing endoparasite pasteuria ramosa. we found that d. magna possesses two cell types circulating in the haemolymph: a spherical one, which we call a granulocyte and an irregular-shaped amoeboid cell first ... | 2010 | 20534618 |
| fitness and virulence of a bacterial endoparasite in an environmentally stressed crustacean host. | host-parasite interactions are shaped by the co-evolutionary arms race of parasite virulence, transmission success as well as host resistance and recovery. the virulence and fitness of parasites may depend on host condition, which is mediated, for instance, by host energy constraints. here, we investigated to what extent stress imposed by predation threat and environmental pollutants influences host-parasite interactions. we challenged the crustacean host daphnia magna with the sterilizing bacte ... | 2011 | 20663250 |
| phenoloxidase but not lytic activity reflects resistance against pasteuria ramosa in daphnia magna. | the field of ecological immunology strongly relies on indicators of immunocompetence. two major indicators in invertebrates, the activity of phenoloxidase (po) and lytic activity have recently been questioned in studies showing that, across a natural range of baseline levels, these indicators did not predict resistance against a manipulated challenge with natural parasites. we confirmed this finding by showing that baseline levels of po and lytic activity in the host daphnia magna were not relat ... | 2011 | 20810432 |
| 'candidatus pasteuria aldrichii' sp. nov., an obligate endoparasite of the bacterivorous nematode, bursilla sp. | a pasteuria species was discovered parasitizing the bacterivorous nematode, bursilla sp. from selected bermudagrass (cynodon sp.) field plots in davie, fl. soil containing this bacterium was isolated and supplied with bi-weekly inoculations of cultured bursilla sp. in order to build and maintain a source of endospores for continuous in vivo maintenance of the pasteuria for further study and characterization. 16s rdna sequence homology supported its congeneric ranking with other pasteuria species ... | 2010 | 20870891 |
| successfully resisting a pathogen is rarely costly in daphnia magna. | a central hypothesis in the evolutionary ecology of parasitism is that trade-offs exist between resistance to parasites and other fitness components such as fecundity, growth, survival, and predator avoidance, or resistance to other parasites. these trade-offs are called costs of resistance. these costs fall into two broad categories: constitutive costs of resistance, which arise from a negative genetic covariance between immunity and other fitness-related traits, and inducible costs of resistan ... | 2010 | 21083915 |
| cloning of the unculturable parasite pasteuria ramosa and its daphnia host reveals extreme genotype-genotype interactions. | the degree of specificity in host-parasite interactions has important implications for ecology and evolution. unfortunately, specificity can be difficult to determine when parasites cannot be cultured. in such cases, studies often use isolates of unknown genetic composition, which may lead to an underestimation of specificity. we obtained the first clones of the unculturable bacterium pasteuria ramosa, a parasite of daphnia magna. clonal genotypes of the parasite exhibited much more specific int ... | 2010 | 21091597 |
| identifying energy constraints to parasite resistance. | life-history theory suggests that energetically expensive traits may trade off against each other, resulting in costs associated with the development or maintenance of a particular phenotype. the deployment of resistance mechanisms during parasite exposure is one such trait, and thus their potential benefit in fighting off parasites may be offset by costs to other fitness-related traits. in this study, we used trade-off theory as a basis to test whether stimulating an increased development rate ... | 2011 | 21210532 |
| resolving the infection process reveals striking differences in the contribution of environment, genetics and phylogeny to host-parasite interactions. | infection processes consist of a sequence of steps, each critical for the interaction between host and parasite. studies of host-parasite interactions rarely take into account the fact that different steps might be influenced by different factors and might, therefore, make different contributions to shaping coevolution. we designed a new method using the daphnia magna - pasteuria ramosa system, one of the rare examples where coevolution has been documented, in order to resolve the steps of the i ... | 2011 | 21342515 |
| evolutionary ecotoxicology of pesticide resistance: a case study in daphnia. | natural populations that are exposed to pesticides in their environment may at the same time be exposed to natural stressors like parasites and predators, which may interact with pesticide exposure. this may not only impact target pest species but also a wide variety of non-target species. this review reports on a joint research program in the water flea daphnia magna, a non-target species often used as model organism in ecology and ecotoxicology. the focus is on different aspects that are of ke ... | 2011 | 21380529 |
| epidemiological, evolutionary, and coevolutionary implications of context-dependent parasitism. | abstract victims of infection are expected to suffer increasingly as parasite population growth increases. yet, under some conditions, faster-growing parasites do not appear to cause more damage, and infections can be quite tolerable. we studied these conditions by assessing how the relationship between parasite population growth and host health is sensitive to environmental variation. in experimental infections of the crustacean daphnia magna and its bacterial parasite pasteuria ramosa, we show ... | 2011 | 21460572 |
| the expression of virulence during double infections by different parasites with conflicting host exploitation and transmission strategies. | in many natural populations, hosts are found to be infected by more than one parasite species. when these parasites have different host exploitation strategies and transmission modes, a conflict among them may arise. such a conflict may reduce the success of both parasites, but could work to the benefit of the host. for example, the less-virulent parasite may protect the host against the more-virulent competitor. we examine this conflict using the waterflea daphnia magna and two of its sympatric ... | 2011 | 21481055 |
| candidate innate immune system gene expression in the ecological model daphnia. | the last ten years have witnessed increasing interest in host-pathogen interactions involving invertebrate hosts. the invertebrate innate immune system is now relatively well characterised, but in a limited range of genetic model organisms and under a limited number of conditions. immune systems have been little studied under real-world scenarios of environmental variation and parasitism. thus, we have investigated expression of candidate innate immune system genes in the water flea daphnia, a m ... | 2011 | 21550363 |
| identification of new snp- based markers for inter and intra-species discrimination of obligate bacterial parasites (pasteuria spp.) of invertebrates. | protein encoding and 16s rrna genes of pasteuria penetrans populations from a wide range of geographic locations were examined. most inter-population single nucleotide polymorphisms (snps) were detected in the 16s rrna gene. however, in order to fully resolve all populations these were supplemented with snps from protein-encoding genes in a multi-locus snp typing approach. examination of individual 16s rrna gene sequences revealed the occurrence of 'cryptic' snps which were not present in the co ... | 2011 | 21803895 |
| characterisation of a large family of polymorphic collagen-like proteins in the endospore-forming bacterium pasteuria ramosa. | collagen-like proteins containing glycine-x-y repeats have been identified in several pathogenic bacteria potentially involved in virulence. recently, a collagen-like surface protein, pcl1a, was identified in pasteuria ramosa, a spore-forming parasite of daphnia. here we characterise 37 novel putative p. ramosa collagen-like protein genes (pcls). pcr amplification and sequencing across 10 p. ramosa strains showed they were polymorphic, distinguishing genotypes matching known differences in daphn ... | 2011 | 21726633 |
| Who benefits from reduced reproduction in parasitized hosts? An experimental test using the Pasteuria ramosa-Daphnia magna system. | SUMMARYWe investigated whether parasites or hosts benefit from reduced reproduction in infected hosts. When parasites castrate their hosts, the regain of host reproduction is necessary for castration to be a host adaptation. When infecting Daphnia magna with Pasteuria ramosa, in a lake water based medium, 49·2% of the castrated females regained reproduction. We investigated the relationship between castration level, and parasite and host fitness proxies to determine the adaptive value of host ca ... | 2011 | 21854675 |
| collateral damage: rapid exposure-induced evolution of pesticide resistance leads to increased susceptibility to parasites. | although natural populations may evolve resistance to anthropogenic stressors such as pollutants, this evolved resistance may carry costs. using an experimental evolution approach, we exposed different daphnia magna populations in outdoor containers to the carbamate pesticide carbaryl and control conditions, and assessed the resulting populations for both their resistance to carbaryl as well as their susceptibility to infection by the widespread bacterial microparasite pasteuria ramosa. our resu ... | 2011 | 21884064 |
| resistance to a bacterial parasite in the crustacean daphnia magna shows mendelian segregation with dominance. | the influence of host and parasite genetic background on infection outcome is a topic of great interest because of its pertinence to theoretical issues in evolutionary biology. in the present study, we use a classical genetics approach to examine the mode of inheritance of infection outcome in the crustacean daphnia magna when exposed to the bacterial parasite pasteuria ramosa. in contrast to previous studies in this system, we use a clone of p. ramosa, not field isolates, which allows for a mor ... | 2011 | 22167056 |
| genetic variation for maternal effects on parasite susceptibility. | the expression of infectious disease is increasingly recognized to be impacted by maternal effects, where the environmental conditions experienced by mothers alter resistance to infection in offspring, independent of heritability. here, we studied how maternal effects (high or low food availability to mothers) mediated the resistance of the crustacean daphnia magna to its bacterial parasite pasteuria ramosa. we sought to disentangle maternal effects from the effects of host genetic background by ... | 2011 | 21848987 |
| Pasteuria endospores from Heterodera cajani (Nematoda: Heteroderidae) exhibit inverted attachment and altered germination in cross-infection studies with Globodera pallida (Nematoda: Heteroderidae). | The Pasteuria group of Gram-positive, endospore-forming bacteria are parasites of invertebrates and exhibit differences in host specificity. We describe a cross-infection study between an isolate of Pasteuria from pigeon pea cyst nematode, Heterodera cajani, which also infects the potato cyst nematode, Globodera pallida, from the United Kingdom. A proportion of the attached endospores, 13% on H. cajani and 22% on G. pallida adhere to the cuticle in an inverted orientation. Inverted and conventio ... | 2011 | 22092805 |