Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| '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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| prophenoloxidase in daphnia magna: cdna sequencing and expression in relation to resistance to pathogens. | invertebrates utilise the innate immune system when defending against pathogenic attack. however, except for some effectors as prophenoloxidase (propo), the innate immune response is less well understood outside model insect species, and its role in natural host-pathogen systems is generally not well documented. we have therefore initiated studies on the immune response of the crustacean daphnia when exposed to the specialist endobacterial pathogen, pasteuria ramosa. this study was focused on th ... | 2009 | 19103220 |
| 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 |
| 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 |
| 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 |
| 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 |
| bacterial infection changes the elemental composition of daphnia magna. | 1. an animal's elemental composition can be an important indicator of its physiological state and role in ecosystem nutrient cycling. we examined the interactive effects of bacterial (pasteuria ramosa) infection and phosphorus (p)-poor food on the body stoichiometry of daphnia magna. daphnia were exposed to or held free of a bacterial parasite and fed algal food of different c:p ratios (100-500) over a 28-day period. 2. to assess the effects of exposure and infection on daphnia stoichiometry, we ... | 2008 | 18631369 |
| the effects of multiple infections on the expression and evolution of virulence in a daphnia-endoparasite system. | multiple infections of a host by different strains of the same microparasite are common in nature. although numerous models have been developed in an attempt to predict the evolutionary effects of intrahost competition, tests of the assumptions of these models are rare and the outcome is diverse. in the present study we examined the outcome of mixed-isolate infections in individual hosts, using a single clone of the waterflea daphnia magna and three isolates of its semelparous endoparasite paste ... | 2008 | 18384658 |
| responses of a bacterial pathogen to phosphorus limitation of its aquatic invertebrate host. | host nutrition is thought to affect the establishment, persistence, and severity of pathogenic infections. nutrient-deficient foods possibly benefit pathogens by constraining host immune function or benefit hosts by limiting parasite growth and reproduction. however, the effects of poor elemental food quality on a host's susceptibility to infection and disease have received little study. here we show that the bacterial microparasite pasteuria ramosa is affected by the elemental nutrition of its ... | 2008 | 18409420 |
| experimental evolution of field populations of daphnia magna in response to parasite treatment. | although there is little doubt that hosts evolve to reduce parasite damage, little is known about the evolutionary time scale on which host populations may adapt under natural conditions. here we study the effects of selection by the microsporidian parasite octosporea bayeri on populations of daphnia magna. in a field study, we infected replicated populations of d. magna with the parasite, leaving control populations uninfected. after two summer seasons of experimental evolution (about 15 genera ... | 2008 | 18462312 |
| host-parasite coevolution: insights from the daphnia-parasite model system. | daphnia and its parasites have become recognized as a model system for studying the epidemiological, evolutionary and genetic interactions between hosts and parasites. the key advantages of the daphnia-parasite system are the propagation of the host as iso-female lines, that is clonal, but at the same time the possibility to cross lines. furthermore, daphnia have diverse parasites, including bacteria, fungi, microsporidia and helminths, which can be kept in culture with the hosts. for two parasi ... | 2008 | 18556238 |
| temperature-dependent costs of parasitism and maintenance of polymorphism under genotype-by-environment interactions. | the maintenance of genetic variation for infection-related traits is often attributed to coevolution between hosts and parasites, but it can also be maintained by environmental variation if the relative fitness of different genotypes changes with environmental variation. to gain insight into how infection-related traits are sensitive to environmental variation, we exposed a single host genotype of the freshwater crustacean daphnia magna to four parasite isolates (which we assume to represent dif ... | 2008 | 18557795 |
| inter- and intra-specific cuticle variation between amphimictic and parthenogenetic species of root-knot nematode (meloidogyne spp.) as revealed by a bacterial parasite (pasteuria penetrans). | specific host-parasite interactions exist between species and strains of plant parasitic root-knot nematodes and the gram-positive bacterial hyperparasite pasteuria penetrans. this bacterium produces endospores that adhere to the cuticle of migrating juveniles, germinate and colonise the developing female within roots. endospore attachment of p. penetrans populations to second-stage juveniles of the root-knot nematode species meloidogyne incognita and meloidogyne hapla showed there were interact ... | 2008 | 18171577 |
| a quantitative test of the relationship between parasite dose and infection probability across different host-parasite combinations. | epidemiological models generally assume that the number of susceptible individuals that become infected within a unit of time depends on the density of the hosts and the concentration of parasites (i.e. mass-action principle). however, empirical studies have found significant deviations from this assumption due to biotic and abiotic factors, such as seasonality, the spatial structure of the host population and host heterogeneity with respect to immunity and susceptibility. in this paper, we exam ... | 2008 | 18198145 |
| genetic and immunological comparison of the cladoceran parasite pasteuria ramosa with the nematode parasite pasteuria penetrans. | pasteuria penetrans, an obligate endospore-forming parasite of meloidogyne spp. (root knot nematodes), has been identified as a promising agent for biocontrol of these destructive agricultural crop pests. pasteuria ramosa, an obligate parasite of water fleas (daphnia spp.), has been shown to modulate cladoceran populations in natural ecosystems. selected sporulation genes and an epitope associated with the spore envelope of these related species were compared. the sige and spoiiaa/spoiiab genes ... | 2008 | 17933927 |
| parasite variation and the evolution of virulence in a daphnia-microparasite system. | understanding genetic relationships amongst the life-history traits of parasites is crucial for testing hypotheses on the evolution of virulence. this study therefore examined variation between parasite isolates (the bacterium pasteuria ramosa) from the crustacean daphnia magna. from a single wild-caught infected host we obtained 2 p. ramosa isolates that differed substantially in the mortality they caused. surprisingly, the isolate causing higher early mortality was, on average, less successful ... | 2008 | 18005474 |
| variable-number-of-tandem-repeats analysis of genetic diversity in pasteuria ramosa. | variable-number-of-tandem-repeats (vntr) markers are increasingly being used in population genetic studies of bacteria. they were recently developed for pasteuria ramosa, an endobacterium that infects daphnia species. in the present study, we genotyped p. ramosa in 18 infected hosts from the united kingdom, belgium, and two lakes in the united states using seven vntr markers. two daphnia species were collected: d. magna and d. dentifera. six loci showed length polymorphism, with as many as five ... | 2008 | 18214600 |
| morphological and molecular characteristics of a new species of pasteuria parasitic on meloidogyne ardenensis. | a species of the hyper-parasitic bacterium pasteuria was isolated from the root-knot nematode meloidogyne ardenensis infecting the roots of ash (fraxinus excelsior). it is morphologically different from some other pasteuria pathogens of nematodes in that the spores lack a basal ring on the ventral side of the spore and have a unique clumping nature. transmission electron microscopy (tem) showed that the clumps of spores are not random aggregates but result from the disintegration of the suicide ... | 2007 | 17399736 |
| parasite-driven genetic change in a natural population of daphnia. | a substantial body of theory indicates that parasites may mould the population genetic structure of their hosts, but few empirical studies have directly linked parasitism to genetic dynamics. we used molecular markers (allozymes) to investigate genotype frequency changes in a natural population of the crustacean daphnia magna in relation to an epidemic of the bacterial pathogen pasteuria ramosa. the population experienced a severe epidemic during the study period in which parasite prevalence rea ... | 2007 | 17439612 |
| evidence for a cost of immunity when the crustacean daphnia magna is exposed to the bacterial pathogen pasteuria ramosa. | the deployment of the immune system has the obvious potential to ameliorate infection outcomes, but immune responses can also harm hosts by either damaging host tissues or monopolizing resources, leading to enhanced mortality. to gain insight into such a 'cost of immunity' when the crustacean daphnia magna is challenged with the bacterium pasteuria ramosa, we measured survivorship among hosts that resisted infection following exposure to various strains and doses of the parasite. in the first of ... | 2007 | 17922716 |
| transfer and development of pasteuria penetrans. | pasteuria penetrans isolate p-20 has been attributed as the cause of soil suppressiveness to peanut root-knot nematode in florida. in this study, p. penetrans was transferred from a suppressive site to a new site and established by growing susceptible hosts to the peanut root-knot nematode during both summer and winter seasons. when two soil fumigants, 1,3-dichloropropene (1,3-d) and chloropicrin, were applied broadcast at the rate of 168 liters/ha and 263 kg/ha, respectively, the bacterium was ... | 2007 | 19259476 |
| variable-number tandem repeats as molecular markers for biotypes of pasteuria ramosa in daphnia spp. | variable-number tandem repeats (vntrs) have been identified in populations of pasteuria ramosa, a castrating endobacterium of daphnia species. the allelic polymorphisms at 14 loci in laboratory and geographically diverse soil samples showed that vntrs may serve as biomarkers for the genetic characterization of p. ramosa isolates. | 2007 | 17400766 |
| multiple-strand displacement and identification of single nucleotide polymorphisms as markers of genotypic variation of pasteuria penetrans biotypes infecting root-knot nematodes. | pasteuria species are endospore-forming obligate bacterial parasites of soil-inhabiting nematodes and water-inhabiting cladocerans, e.g. water fleas, and are closely related to bacillus spp. by 16s rrna gene sequence. as naturally occurring bacteria, biotypes of pasteuria penetrans are attractive candidates for the biocontrol of various meloidogyne spp. (root-knot nematodes). failure to culture these bacteria outside their hosts has prevented isolation of genomic dna in quantities sufficient for ... | 2007 | 17578522 |
| a method for isolation of pasteuria penetrans endospores for bioassay and genomic studies. | a rapid method for collection of pasteuria penetrans endospores was developed. roots containing p. penetrans-infected root-knot nematode females were softened by pectinase digestion, mechanically processed, and filtered to collect large numbers of viable endospores. this method obviates laborious handpicking of pasteuria-infected females and yields endospores competent to attach to and infect nematodes. endospores are suitable for morphology studies and dna preparations. | 2006 | 19259442 |
| parasite-host specificity: experimental studies on the basis of parasite adaptation. | specificity in parasitic interactions can be defined by host genotypes that are resistant to only a subset of parasite genotypes and parasite genotypes that are infective on a subset of host genotypes. it is not always clear if specificity is determined by the genotypes of the interactors, or if phenotypic plasticity (sometimes called acclimation) plays a larger role. coevolutionary outcomes critically depend on the pervasiveness of genetic interactions. we studied specificity using the bacteria ... | 2006 | 16568629 |
| parasite-mediated selection and the role of sex and diapause in daphnia. | to gain insight into parasite-mediated natural selection, we studied a natural population of the crustacean daphnia magna during a severe epidemic of the bacterial parasite pasteuria ramosa. we also investigated the relationship between susceptibility and the production of resting eggs, which are only produced during the sexual phase of reproduction. live host samples were taken before and after this epidemic and resistance to p. ramosa was examined in the laboratory. host clones collected after ... | 2006 | 16780519 |
| exploitation of immunofluorescence for the quantification and characterization of small numbers of pasteuria endospores. | the pasteuria group of endospore-forming bacteria has been studied as a biocontrol agent of plant-parasitic nematodes. techniques have been developed for its detection and quantification in soil samples, and these mainly focus on observations of endospore attachment to nematodes. characterization of pasteuria populations has recently been performed with dna-based techniques, which usually require the extraction of large numbers of spores. we describe a simple immunological method for the quantif ... | 2006 | 17118000 |
| emended description of pasteuria nishizawae. | the description of the gram-positive, obligately parasitic, mycelial and endospore-forming bacterium, pasteuria nishizawae, is emended to include additional observations on the life cycle, host specificity and endospore morphology. the nucleotide sequence of the 16s rrna gene is also provided. | 2005 | 16014501 |
| host-parasite and genotype-by-environment interactions: temperature modifies potential for selection by a sterilizing pathogen. | parasite-mediated selection is potentially of great importance in modulating genetic diversity. genetic variation for resistance, the fuel for natural selection, appears to be common in host-parasite interactions, but responses to selection are rarely observed. in the present study, we tested whether environmental variation could mediate infection and determine evolutionary outcomes. temperature was shown to dramatically alter the potential for parasite-mediated selection in two independent labo ... | 2005 | 15792228 |
| ecological implications of parasites in natural daphnia populations. | in natural host populations, parasitism is considered to be omnipresent and to play an important role in shaping host life history and population dynamics. here, we study parasitism in natural populations of the zooplankton host daphnia magna investigating their individual and population level effects during a 2-year field study. our results revealed a rich and highly prevalent community of parasites, with eight endoparasite species (four microsporidia, one amoeba, two bacteria and one nematode) ... | 2005 | 15891825 |
| distribution and downward movement of pasteuria penetrans in field soil. | endospores of pasteuria penetrans were evaluated for their vertical distribution in field soil and their downward movement through soil in the laboratory. in the field trial, the number of endospores attached to second-stage juveniles (j2) of meloidogyne arenaria race 1 varied greatly in different soil depths. there were higher percentages of j2 with endospores attached in former weed fallow plots during the first 3 years of growing peanut than in former bahiagrass and rhizomal peanut plots (p < ... | 2005 | 19262855 |
| structural analysis of divalent metals binding to the bacillus subtilis response regulator spo0f: the possibility for in vitro metalloregulation in the initiation of sporulation. | the presence of a divalent metal ion in a negatively charged aspartic acid pocket is essential for phosphorylation of response regulator proteins. here, we present metal binding studies of the bacillus subtilis response regulator spo0f using nmr and microesi-ms. nmr studies show that the divalent metals ca(2+), mg(2+) and mn(2+) primarily bind, as expected, in the asp pocket phosphorylation site. however, identical studies with cu(2+) show distinct binding effects in three specific locations: (i ... | 2005 | 16333746 |
| development of pasteuria penetrans in meloidogyne javanica females as affected by constantly high vs fluctuating temperature in an in-vivo system. | growth room and glasshouse experiment was conducted to investigate the effect of constant and fluctuating temperatures on the development of pasteuria penetrans a hyperparasite of root-knot nematodes. tomato plants (lycopersicon esculentum mill) were inoculated with meloidogyne javanica second-stage juveniles attached with endospores of p. penetrans and were grown in growth room at 26-29 degrees c and in glasshouse at 20-32 degrees c. the tomato plants were sampled from the growth room after 600 ... | 2005 | 15682497 |
| occurrence, hosts, morphology, and molecular characterisation of pasteuria bacteria parasitic in nematodes of the family plectidae. | parasitic bacteria of the genus pasteuria are reported for three anaplectus and four identified and several unidentified plectus species found in eight countries in various habitats. the pasteurias from plectids agree in essential morphological characters of sporangia and endospores as well as in developmental cycle with those of the pasteuria species and strains described from tylenchid nematodes, but appear to be mainly distinguished from these by absence of a distinct perisporium in the spore ... | 2005 | 15707865 |
| the effect of different initial densities of nematode (meloidogyne javanica) on the build-up of pasteuria penetrans population. | pasteuria penetrans will build-up faster where there is a high initial nematode density and can suppress root-knot nematode populations in the roots of tomato plants. the effect of different initial densities of nematode (meloidogyne javanica) (150, 750, 1500, 3000) and p. penetrans infected females (f1, f3) densities (f0=control and ac=absolute control without nematode or p. penetrans inoculum) on the build-up of pasteuria population was investigated over four crop cycles. two major points of i ... | 2005 | 15633246 |
| phylogenetic analysis of pasteuria penetrans by use of multiple genetic loci. | pasteuria penetrans is a gram-positive, endospore-forming eubacterium that apparently is a member of the bacillus-clostridium clade. it is an obligate parasite of root knot nematodes (meloidogyne spp.) and preferentially grows on the developing ovaries, inhibiting reproduction. root knot nematodes are devastating root pests of economically important crop plants and are difficult to control. consequently, p. penetrans has long been recognized as a potential biocontrol agent for root knot nematode ... | 2005 | 16077116 |
| biological control potential of the obligate parasite pasteuria penetransagainst the root-knot nematode, meloidogyne incognita infestation in brinjal. | the efficacy of the obligate bacterial parasite, pasteuria penetrans against the rootknot nematode, meloidogyne incognita infestation was assessed in brinjal. the seedling pans with sterilized soil were inoculated with nematodes and root powder of p. penetrans were applied at different dosages viz., 0 x 10(6), 0.5 x 10(6) spores and 1 x 10(6) spores/pan. seeds of brinjal cv co2 were sown in the pans and seedlings were allowed to grow. the seedlings were transplanted to microplots containing ster ... | 2005 | 16628937 |
| integrated management of root-knot nematode, meloidogyne incognita infestation in tomato and grapevine. | an integrated approach with the obligate bacterial parasite, pasteuria penetrans and nematicides was assessed for the management of the root-knot nematode, meloidogyne incognita infestation in tomato and grapevine. seedlings of tomato cv. co3 were transplanted into pots filled with sterilized soil and inoculated with nematodes (5000 juveniles/pot). the root powder of p. penetrans at 10 mg/pot was applied alone and in combination with carbofuran at 6 mg/pot. application of p. penetrans along with ... | 2005 | 16628938 |
| persistence and suppressiveness of pasteuria penetrans to meloidogyne arenaria race. | the long-term persistence and suppressiveness of pasteuria penetrans against meloidogyne arenaria race 1 were investigated in a formerly root-knot nematode suppressive site following 9 years of continuous cultivation of three treatments and 4 years of continuous peanut. the three treatments were two m. arenaria race 1 nonhost crops, bahiagrass (paspalum notatum cv. pensacola var. tifton 9), rhizomal peanut (arachis glabrata cv. florigraze), and weed fallow. two root-knot nematode susceptible wee ... | 2004 | 19262836 |
| the evolution of virulence when parasites cause host castration and gigantism. | it has been suggested that the harm parasites cause to their hosts is an unavoidable consequence of parasite reproduction with costs not only for the host but also for the parasite. castrating parasites are thought to minimize their costs by reducing host fecundity, which may minimize the chances of killing both host and parasite prematurely. we conducted a series of experiments to understand the evolution of virulence of a castrating bacterium in the planktonic crustacean daphnia magna. by mani ... | 2004 | 15540139 |
| variation in phenoloxidase activity and its relation to parasite resistance within and between populations of daphnia magna. | estimates of phenoloxidase (po) activity have been suggested as a useful indicator of immunocompetence in arthropods, with the idea that high po activity would indicate high immunocompetence against parasites and pathogens. here, we test for variation in po activity among clones of the planktonic crustacean daphnia magna and its covariation with susceptibility to infections from four different microparasite species (one bacterium and three microsporidia). strong clonal variation in po activity w ... | 2004 | 15306368 |
| a simple method for the extraction, pcr-amplification, cloning, and sequencing of pasteuria 16s rdna from small numbers of endospores. | for many years the taxonomy of the genus pasteuria has been marred with confusion because the bacterium could not be cultured in vitro and, therefore, descriptions were based solely on morphological, developmental, and pathological characteristics. the current study sought to devise a simple method for pcr-amplification, cloning, and sequencing of pasteuria 16s rdna from small numbers of endospores, with no need for prior dna purification. results show that dna extracts from plain glass bead-bea ... | 2004 | 19262793 |
| 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 |
| life cycle, ultrastructure, and host specificity of the north american isolate of pasteuria that parasitizes the soybean cyst nematode, heterodera glycines. | light and transmission electron microscopy were used to investigate the life cycle and ultrastructure of an undescribed isolate of pasteuria that parasitizes the soybean cyst nematode, heterodera glycines. studies also were conducted to determine the host specificity of pasteuria. the endospores that attached to the cuticle of second-stage juveniles (j2) of h. glycines in soil did not germinate until the encumbered nematodes invaded soybean roots. thereafter, the bacterium developed and complete ... | 2004 | 19262804 |
| pasteuria spp.: systematics and phylogeny of these bacterial parasites of phytopathogenic nematodes. | pasteuria spp. include endospore-forming bacterial pathogens of cladoceran crustaceans and plant-parasitic nematodes. propagation of these nematode pathogens requires attachment of soilborne endospores to nematode hosts, infection, growth, sporulation, and release of endospores to repeat the cycle of infection and propagation. the ability of these bacteria to suppress the levels of plant-parasitic nematodes in the field has made them particularly promising candidates for biocontrol of nematode d ... | 2003 | 19265995 |
| 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 |
| temporal formation and immunolocalization of an endospore surface epitope during pasteuria penetrans sporogenesis. | the synthesis and localization of an endospore surface epitope associated with the development of pasteuria penetrans was determined using a monoclonal antibody (mab) as a probe. nematodes, uninfected or infected with p. penetrans, were harvested at 12, 16, 24, and 38 days after inoculation (dai) and then examined to determine the developmental stage of the bacterium. vegetative growth of p. penetrans was observed only in infected nematodes harvested at 12 and 16 dai, whereas cells at different ... | 2003 | 19262762 |
| the infection rate of daphnia magna by pasteuria ramosa conforms with the mass-action principle. | in simple epidemiological models that describe the interaction between hosts with their parasites, the infection process is commonly assumed to be governed by the law of mass action, i.e. it is assumed that the infection rate depends linearly on the densities of the host and the parasite. the mass-action assumption, however, can be problematic if certain aspects of the host-parasite interaction are very pronounced, such as spatial compartmentalization, host immunity which may protect from infect ... | 2003 | 14596538 |
| interactions between bacteria and plant-parasitic nematodes: now and then. | based on genome-to-genome analyses of gene sequences obtained from plant-parasitic, root-knot nematodes (meloidogyne spp.), it seems likely that certain genes have been derived from bacteria by horizontal gene transfer. strikingly, a common theme underpinning the function of these genes is their apparent direct relationship to the nematodes' parasitic lifestyle. phylogenetic analyses implicate rhizobacteria as the predominant group of 'gene donor' bacteria. root-knot nematodes and rhizobia occup ... | 2003 | 13678641 |
| detection and characterization of pasteuria 16s rrna gene sequences from nematodes and soils. | various bacterial species in the genus pasteuria have great potential as biocontrol agents against plant-parasitic nematodes, although study of this important genus is hampered by the current inability to cultivate pasteuria species outside their host. to aid in the study of this genus, an extensive 16s rrna gene sequence phylogeny was constructed and this information was used to develop cultivation-independent methods for detection of pasteuria in soils and nematodes. thirty new clones of paste ... | 2003 | 12656160 |
| parasite-mediated selection in experimental daphnia magna populations. | it has been suggested that parasites are a strong selecting force for their hosts and therefore may alter the outcome of competition among host genotypes. we tested the extent to which parasite-mediated selection by different parasite species influenced competition among clones of the cyclic parthenogen daphnia magna. we monitored clone frequency changes in laboratory microcosm populations consisting of 21 d. magna clones. parasite treatments (two microsporidians, glugoides intestinalis and ordo ... | 2003 | 12683522 |
| 'candidatus pasteuria usgae' sp. nov., an obligate endoparasite of the phytoparasitic nematode belonolaimus longicaudatus. | taxonomically relevant characteristics of a fastidiously gram-positive, obligately endoparasitic prokaryote (strain s-1) that uses the phytoparasitic sting nematode belonolaimus longicaudatus as its host are reviewed. 16s rdna sequence similarity (> or = 93%) confirms its congeneric ranking with other pasteuria species and strains from nematodes and cladocerans and corroborates morphological, morphometric and host range evidence suggesting a novel taxon. the 16s rdna sequence of strain s-1 has g ... | 2003 | 12656173 |
| maternal transfer of strain-specific immunity in an invertebrate. | the most celebrated component of the vertebrate immune system is the acquired response in which memory cells established during primary infection enhance the proliferation of antibodies during secondary infection. additionally, the strength of vertebrate acquired immune responses varies dramatically depending on the infecting pathogen species or on the pathogen genotype within species. because invertebrates lack the t-cell receptors and major histocompatibility complex (mhc) molecules that media ... | 2003 | 12646131 |
| united states department of agriculture-agricultural research service research programs on microbes for management of plant-parasitic nematodes. | restrictions on the use of conventional nematicides have increased the need for new methods of managing plant-parasitic nematodes. consequently, nematode-antagonistic microbes, and active compounds produced by such organisms, are being explored as potential additions to management practices. programs in this area at the usda agricultural research service investigate applied biocontrol agents, naturally occurring beneficial soil microbes and natural compounds. specific research topics include use ... | 2003 | 12846316 |
| morphology and ultrastructure of a pasteuria form parasitic in tylenchorhynchus cylindricus (nematoda). | 2003 | 12725816 | |
| physiology of immunity in the water flea daphnia magna: environmental and genetic aspects of phenoloxidase activity. | in an attempt to understand the ecological correlates of immunocompetence in daphnia magna (crustacea, cladocera), we tested for variation in immune function in relation to feeding conditions, host conditions, and host genotype. we investigated both phenotypic (environmental dependent and condition dependent) as well as genotypic aspects of the prophenoloxidase activating system (pro-poas), which has been described as a key factor in invertebrate immunity. daphnia magna is an ideal study system ... | 2003 | 14988798 |
| phylogenetic analysis and confirmation of the endospore-forming nature of pasteuria penetrans based on the spo0a gene. | pasteuria penetrans is an obligate parasite of plant parasitic nematodes and has yet to be grown in vitro. we have cloned the pivotal sporulation gene, spo0a, which is the first whole gene yet to come from this organism. partial spo0a sequences were also obtained from the related bacteria, pasteuria ramosa and alicyclobacillus acidocaldarius. phylogenetic analyses using the spo0a sequence data from this and previous studies confirmed the closeness of the genera pasteuria and members of the super ... | 2003 | 12951249 |
| description of tylenchorhynchus shimizui n. sp. from paraguay and notes on t. leviterminalis siddiqi, mukherjee & dasgupta from japan (nematoda: tylenchida: telotylenchidae). | a new species of tylenchorhynchus cobb, 1913 from paraguay, t. shimizui n. sp., and t. leviterminalis siddiqi, mukherjee & dasgupta, 1982 from japan are described and illustrated. t. shimizui n. sp. is a monosexual species characterised by females with a medium-sized body, l=0.70-0.82 mm, stylet 18.4-20.8 microm long, a rounded lip region slightly set off from the body contours bearing six annules, oesophageal glands slightly overlapping the intestine laterally and a subcylindrical tail with a b ... | 2002 | 11912343 |
| apomictic, polyphagous root-knot nematodes: exceptionally successful and damaging biotrophic root pathogens. | most apomictic root-knot nematodes (rkn; meloidogyne spp.) have host ranges that encompass the majority of flowering plants, and m. incognita is possibly the world's most damaging crop pathogen. the ancestors, age, and origins of the polyphagous rkn are obscure, but there is increasing evidence that m. incognita, m. javanica, and m. arenaria are closely related, heterogeneous species with a recent, hybrid (reticulate) origin. if so, they must owe much of their current worldwide distributions to ... | 2001 | 11701859 |
| the interaction between the gelatin-binding domain of fibronectin and the attachment of pasteuria penetrans endospores to nematode cuticle. | pasteuria penetrans is a gram-positive endospore-producing bacterium that is a parasite of root-knot nematodes. attachment of endospores to the cuticle of the nematode is the first stage in the infection process. western blot analysis with monoclonal and polyclonal antibodies that recognize the 30 kda heparin-binding domain (hbd) and the 45 kda gelatin-binding domain (gbd) fragments of human fibronectin (fn) revealed a series of polypeptides of approximately 40, 45 and 55 kda present in crude cu ... | 2001 | 11578090 |
| temporal patterns of genetic variation for resistance and infectivity in a daphnia-microparasite system. | theoretical studies have indicated that the population genetics of host-parasite interactions may be highly dynamic. with parasites perpetually adapting to common host genotypes and hosts evolving resistance to common parasite genotypes. the present study examined temporal variation in resistance of hosts and infectivity of parasites within three populations of daphnia magna infected with the sterilizing bacterium pasteuria ramosa. parasite isolates and host clones were collected in each of two ... | 2001 | 11475050 |
| genetic variation in a host-parasite association: potential for coevolution and frequency-dependent selection. | models of host-parasite coevolution assume the presence of genetic variation for host resistance and parasite infectivity, as well as genotype-specific interactions. we used the freshwater crustacean daphnia magna and its bacterial microparasite pasteuria ramosa to study genetic variation for host susceptibility and parasite infectivity within each of two populations. we sought to answer the following questions: do host clones differ in their susceptibility to parasite isolates? do parasite isol ... | 2001 | 11475049 |
| cuticle heterogeneity as exhibited by pasteuria spore attachment is not linked to the phylogeny of parthenogenetic root-knot nematodes (meloidogyne spp.). | the cuticle is a major barrier prohibiting the infection of nematodes against micro-organisms. the attachment of bacterial spores of the nematode hyperparasite pasteuria penetrans (pp1) to field populations of root-knot nematodes (rkn, meloidogyne spp.) from burkino faso, ecuador, greece, malawi, senegal and trinidad and tobago were assayed in standard attachment tests. the attachment of spore population pp1 to different field populations of root-knot nematode showed that the rates of attachment ... | 2001 | 11197759 |
| ultrastructure and development of pasteuria sp. (s-1 strain), an obligate endoparasite of belonolaimus longicaudatus (nemata: tylenchida). | pasteuria sp., strain s-1, is a gram-positive, obligate endoparasitic bacterium that uses the phytoparasitic sting nematode, belonolaimus longicaudatus, as its host in florida. the host attachment of s-1 appears to be specific to the genus belonolaimus with development occurring only in juveniles and adults of b. longicaudatus. this bacterium is characterized from other described species of pasteuria using ultrastructure of the mature endospore. penetration, development, and sporogenesis were el ... | 2001 | 19265886 |
| phenotypic and molecular analysis of a pasteuria strain parasitic to the sting nematode. | pasteuria strain s-1 was found to parasitize the sting nematode belonolaimus longicaudatus. s-1 spores attached to several strains of b. longicaudatus from different geographical locations within the united states. however, they did not adhere to any of the following species: heterodera schachtii, longidorus africanus, meloidogyne hapla, m. incognita, m. javanica, pratylenchus brachyurus, p. scribneri, p. neglectus, p. penetrans, p. thornei, p. vulnus, and xiphinema spp. the 16s rrna genes from ... | 2001 | 19266005 |
| extraction and purification of pasteuria spp. endospores. | pasteuria penetrans is an endospore-forming bacterial parasite of root-knot nematodes that has potential as a biological control agent. biochemical investigations of p. penetrans are limited because of difficulty in obtaining large quantities of endospores free of plant debris and contaminating microorganisms. our objective was to develop a technique for extraction and purification of p. penetrans endospores from root-knot nematodes. tomato roots infected with meloidogyne arenaria that was paras ... | 2000 | 19270952 |
| seasonality of tylenchulus semipenetrans cobb and pasteuria sp. in citrus orchards in spain. | population densities of the mediterranean biotype of tylenchulus semipenetrans were monitored in soil and citrus roots at 3-month intervals for 3 consecutive years in four citrus orchards in the provinces of tarragona (amposta and xalamera) and valencia (moncada and ca rcer). nematode population densities in soil peaked once a year in april or july depending on the orchard and year. numbers of females per gram of root increased once or twice each year. the maximum density of eggs per gram of roo ... | 2000 | 19271018 |
| phylogenetic position of the north american isolate of pasteuria that parasitizes the soybean cyst nematode, heterodera glycines, as inferred from 16s rdna sequence analysis. | a 1341 bp sequence of the 16s rdna of an undescribed species of pasteuria that parasitizes the soybean cyst nematode, heterodera glycines, was determined and then compared with a homologous sequence of pasteuria ramosa, a parasite of cladoceran water fleas of the family daphnidae. the two pasteuria sequences, which diverged from each other by a dissimilarity index of 7%, also were compared with the 16s rdna sequences of 30 other bacterial species to determine the phylogenetic position of the gen ... | 2000 | 10758866 |
| the cause of parasitic infection in natural populations of daphnia (crustacea: cladocera): the role of host genetics. | disease patterns in nature may be determined by genetic variation for resistance or by factors, genetic or environmental, which influence the host-parasite encounter rate. elucidating the cause of natural infection patterns has been a major pursuit of parasitologists, but it also matters for evolutionary biologists because host resistance genes must influence the expression of disease if parasite-mediated selection is to occur. we used a model system in order to disentangle the strict genetic co ... | 2000 | 11416906 |
| attachment tests of pasteuria penetrans to the cuticle of plant and animal parasitic nematodes, free living nematodes and srf mutants of caenorhabditis elegans. | populations of pasteuria penetrans isolated from root-knot nematodes (meloidogyne spp.) and cyst nematodes (heterodera spp.) were tested for their ability to adhere to a limited selection of sheathed and ex-sheathed animal parasitic nematodes, free living nematodes, including caenorhabditis elegans wild type and several srf mutants, and plant parasitic nematodes. the attachment of spores of pasteuria was restricted and no spores were observed adhering to any of the animal parasitic nematodes eit ... | 1999 | 10431371 |
| effects of fluctuating temperatures and different host plants on development of pasteuria penetrans in meloidogyne javanica. | greenhouse and growth room experiments were conducted to investigate the effect of host plant in relation to different nematode inoculum levels, and temperature fluctuations on the development of pasteuria penetrans. host plant affected the development of p. penetrans indirectly through its effect on nematode development. endospores collected from meloidogyne javanica females reared on different hosts did not show any differences in subsequent attachment and infectivity. the numbers of endospore ... | 1999 | 19270902 |
| phylogenetic analysis of pasteuria penetrans by 16s rrna gene cloning and sequencing. | pasteuria penetrans is an endospore-forming bacterial parasite of meloidogyne spp. this organism is among the most promising agents for the biological control of root-knot nematodes. in order to establish the phylogenetic position of this species relative to other endospore-forming bacteria, the 16s ribosomal genes from two isolates of p. penetrans, p-20, which preferentially infects m. arenaria race 1, and p-100, which preferentially infects m. incognita and m. javanica, were pcr-amplified from ... | 1999 | 19270903 |
| review of pasteuria penetrans: biology, ecology, and biological control potential. | pasteuria penetrans is a mycelial, endospore-forming, bacterial parasite that has shown great potential as a biological control agent of root-knot nematodes. considerable progress has been made during the last 10 years in understanding its biology and importance as an agent capable of effectively suppressing root-knot nematodes in field soil. the objective of this review is to summarize the current knowledge of the biology, ecology, and biological control potential of p. penetrans and other past ... | 1998 | 19274225 |
| population changes in heterodera glycines and its bacterial parasite pasteuria sp. in naturally infested soil. | a two-year soil sampling study was conducted on four microplots naturally infested with heterodera glycines and an undescfibed species of pasteuria. the objectives of the study were to investigate the population dynamics of both organisms and to assess the potential of pasteuria sp. as a biological control agent of h. glycines. seasonal fluctuations were observed in numbers of cysts, eggs per cyst, second-stage juveniles (j2) of h. glycines, number of pasteuria endospores attached per j2, and pe ... | 1998 | 19274202 |
| observations on a pasteuria isolate parasitic on hoplolaimus galeatus in peru. | a pasteuria isolate associated with a population of the lance nematode hoplolaimus galeatus was discovered in peru. the infective propagules adhered to adult stages and juveniles and were found filling the bodies of males and females. the endospore and central core diameters measured 4.5 +/- 0.4 pm and 1.9 +/- 0.2 mum, respectively, which differed from those reported for other pasteuria isolates found iu north america on the same host. examinations of endospore ultrastructure with scanning elect ... | 1998 | 19274212 |
| effects of monoclonal antibodies, cationized ferritin, and other organic molecules on adhesion of pasteuria penetrans endospores to meloidogyne incognita. | the incidence of adhesion of pasteuria penetrans endospores to meloidogyne incognita second-stage juveniles (j2) was studied after pretreatment of the latter with monoclonal antibodies (mab), cationized ferritin, and other organic molecules in replicated trials. monoclonal antibodies developed to a cuticular epitope of m. incognita second-stage juveniles gave significant reductions in attachment of p. penetrans endospores to treated nematodes. mab bound to the entire length of j2 except for the ... | 1997 | 19274193 |
| suppression mechanisms of meloidogyne arenaria race 1 by pasteuria penetrans. | the biological control of meloidogyne arenaria on peanut (arachis hypogaea) by pasteuria penetrans was evaluated using a six x six factorial experiment in field microplots over 2 years. the main factors were six inoculum levels of second-stage juveniles (j2) of m. arenaria race 1 (0, 40, 200, 1,000, 5,000, and 25,000 j2/microplot, except that the highest level was 20,000 j2/microplot in 1995) and six infestation levels of p. penetrans as percentages of j2 with endospores attached (0, 20, 40, 60, ... | 1997 | 19274127 |
| temperature-dependent development of pasteuria penetrans in meloidogyne arenaria. | pasteuria penetrans is a promising biological control agent of plant-parasitic nematodes. this study was conducted to determine effects of temperature on the bacterium's development in meloidogyne arenaria. developmental stages of p. penetrans were viewed with a compound microscope and verified with scanning electron microscopy within each nematode at 100 accumulated degree-day intervals by tracking accumulated degree-days at three temperatures (21, 28, and 35 degrees c). five predominant develo ... | 1997 | 19274154 |