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Patricia S Stock - One of the best experts on this subject based on the ideXlab platform.
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partners in crime symbiont assisted resource acquisition in Steinernema entomopathogenic nematodes
Current opinion in insect science, 2019Co-Authors: Patricia S StockAbstract:Entomopathogenic nematodes in the genus Steinernema (Nematoda: Steinernematidae) have a mutualistic relationship with Xenorhabdus bacteria (Gram-negative Enterobacteriaceae). This partnership however, is pathogenic to a wide range of insect species. Because of their potent insecticidal ability, they have successfully been implemented in biological control and integrated pest management programs worldwide. Steinernema-Xenorhabdus-insect partnerships are extremely diverse and represent a model system in ecology and evolution to investigate symbioses between invertebrates and microbes. The reproductive fitness of the nematode-bacterium partnership is tightly associated, and maintenance of their virulence is critical to the conversion of the insect host as a suitable environment where this partnership can be perpetuated.
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xenorhabdus bovienii cs03 the bacterial symbiont of the entomopathogenic nematode Steinernema weiseri is a non virulent strain against lepidopteran insects
Journal of Invertebrate Pathology, 2015Co-Authors: Bernard Duvic, Alain Givaudan, Gaelle Bisch, John G Mcmullen, Patricia S Stock, Sylvie PagesAbstract:Xenorhabdus bacteria (γ-proteobacteria: Enterobacteriaceae) have dual lifestyles. They have a mutualistic relationship with Steinernema nematodes (Nematoda: Steinernematidae) and are pathogenic to a wide range of insects. Each Steinernema nematode associates with a specific Xenorhabdus species. However, a Xenorhabdus species can have multiple nematode hosts. For example, Xenorhabdus bovienii (Xb) colonizes at least nine Steinernema species from two different phylogenetic clades. The Steinernema–Xb partnership has been found in association with different insect hosts. Biological and molecular data on the Steinernema jollieti–Xb strain SS-2004 pair have recently been described. In particular, the Xb SS-2004 bacteria are virulent alone after direct injection into insect, making this strain a model for studying Xb virulence. In this study, we searched for Xb strains attenuated in virulence. For this purpose, we underwent infection assays with five Steinernema spp.–Xb pairs with two insects, Galleria mellonella (Lepidoptera: Pyralidae) and Spodoptera littoralis (Lepidoptera: Noctuidae). The S. weiseri–Xb CS03 pair showed attenuated virulence and lower fitness in S. littoralis in comparison to the other nematode-bacteria pairs. Furthermore, when injected alone into the hemolymph of G. mellonella or S. littoralis, the Xb CS03 bacterial strain was the only non-virulent strain. By comparison with the virulent Xb SS-2004 strain, Xb CS03 showed an increased sensitivity to the insect antimicrobial peptides, suggesting an attenuated response to the insect humoral immunity. To our current knowledge, Xb CS03 is the first non-virulent Xb strain identified. We propose this strain as a new model for studying the Xenorhabdus virulence.
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Steinernema tophus sp n nematoda Steinernematidae a new entomopathogenic nematode from south africa
Zootaxa, 2014Co-Authors: Harun Cimen, Selcuk Hazir, Justin Hatting, Ming Min Lee, Patricia S StockAbstract:A new entomopathogenic nematode, Steinernema tophus n. sp. is described from South Africa. Morphological, molecular (ribosomal gene sequence data) together with cross-hybridization studies were used for diagnostics and identification purposes. Both molecular and morphological data indicate the new species belongs to the ‘ glaseri -group’ of Steinernema spp. Key morphological diagnostic traits for S. tophus n. sp. include the morphology of the spicules and gubernaculum. Morphometric traits of third-stage infective juveniles, including total body length (average 1,046µm), tail length (average 70µm), location of the excretory pore (average 92 µm), D% (average 63), E% (average 132) and H% (average 32) values are definitive. In addition to these morphological characters, analysis of rDNA (28S and ITS) gene sequences depict this Steinernema species as a distinct and unique entity.
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diversity and evolutionary relationships of entomopathogenic nematodes Steinernematidae and heterorhabditidae from the central andean region of colombia
Nematology, 2007Co-Authors: Juan Carlos Lopeznunez, Liliana Cano, Carmenza E Gongorab, Patricia S StockAbstract:A survey of entomopathogenic nematodes (EPN) was conducted in the Central Andean region of Colombia. Out of a total of 945 soil samples, 28 (3%) were positive for entomopathogenic nematodes. Of them, 26 samples (92.8%) contained Steinernema and two (7.2%) harboured Heterorhabditis isolates. Characterisation of the recovered isolates was done by analysis of rDNA sequences. The large subunit of rDNA (28S) was considered for diagnosis of Steinernema species whereas the internal transcribed spacer region (ITS) of rDNA was used to identify Heterorhabditis isolates recovered in this study. Five Steinernema spp. were isolated and identified as S. websteri and four new, undescribed species. Steinernema websteri was isolated from two sites: Naranjal and Paraguaicito stations. At Naranjal, this species was recovered from a coffee plantation and a forest habitat surrounding these plantations. At Paraguaicito, the same species was recovered from a coffee-guamo habitat. Steinernema sp. 1 was collected from nogal cafetero (Cordia allaidora) groves and forest habitats at Paraguaicito station. Steinernema sp. 2 was found in coffee-guamo habitats both at Naranjal and Paraguaicito stations. Steinernema sp. 3 was the only EPN species recovered at Santa Barbara station in association with plantain. This species was also found at La Catalina station in association with forest habitats and also from soil samples taken from a landscaped area with Heliconia sp. and grass cover (Arachis pintoi) at Cenicafe La Granja station and a coffee-guamo habitat at Naranjal station. Steinernema sp. 4 was found at La Catalina in a forest habitat, also associated with Steinernema sp. 3 (isolate JCL002) and Heterorhabditis sp. 1 (isolate JCL 003). The Heterorhabditis isolates were identified as two undescribed Heterorhabditis spp. Heterorhabditis sp. 1 (isolate JCL003) was recovered at La Catalina station associated with a forest habitat. Heterorhabditis sp. 2 (isolate JCL040) was collected from a coffee-guamo habitat at Naranjal station. Although limited to one geographic region, this study suggests entomopathogenic nematodes in Colombia are quite diverse and are perhaps widely distributed in this country. A more intensive survey covering all geographic regions is currently underway.
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Steinernema scarabaei n sp rhabditida Steinernematidae a natural pathogen of scarab beetle larvae coleoptera scarabaeidae from new jersey usa
Nematology, 2003Co-Authors: Patricia S Stock, Albrecht M. KoppenhöferAbstract:Steinernema scarabaei n. sp. (Rhabditida: Steinernematidae) is a new entomopathogenic nematode isolated from larvae of the scarab beetles Anomala(= Exomala)orientalis and Popillia japonica from turfgrass in New Jersey, USA. Morphology, hybridisation and molecular studies indicated the distinctness of S. scarabaei n. sp. from other Steinernema spp. Distinctive diagnostic characters include: the presence of a mucronated tail in both first generation adults; the presence of a ventrally bifurcated mucro in the first generation female tail; the size and shape of the spicules and gubernaculum and the arrangement of the genital papillae of the male; third-stage infective juvenile with total body length of 890-959 μm and lateral field with eight longitudinal ridges. RFLP analysis of the ITS region of rDNA showed S. scarabaei n. sp. to be distinct from 50 other Steinernema species and isolates. In addition, phylogenetic interpretation of sequence data from the LSU of rDNA provided further evidence for autapomorphies and separate species status for S. scarabaei n. sp.
Erko Stackebrandt - One of the best experts on this subject based on the ideXlab platform.
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description of four novel species of xenorhabdus family enterobacteriaceae xenorhabdus budapestensis sp nov xenorhabdus ehlersii sp nov xenorhabdus innexi sp nov and xenorhabdus szentirmaii sp nov
Systematic and Applied Microbiology, 2005Co-Authors: Katalina Lengyel, Emilia Szallas, Elke Lang, Peter Schumann, Erko StackebrandtAbstract:Abstract The taxonomic affiliation was determined for four Xenorhabdus strains isolated from four Steinernema hosts from different countries. As compared to the five validly described Xenorhabdus species, i.e., X. nematophila, X. japonica, X. beddingii, X. bovienii and X. poinarii , these isolates represented novel species on the basis of 16S rRNA gene sequences and riboprint patterns, as well as by physiological and metabolic properties. They were named Xenorhabdus budapestensis sp. nov., type strain DSM 16342 T , isolated from Steinernema bicornutum ; Xenorhabdus ehlersii sp. nov., type strain DSM 16337 T , isolated from Steinernema serratum ; Xenorhabdus innexi sp. nov., type strain DSM 16336 T isolated from Steinernema scapterisci ; and Xenorhabdus szentirmaii sp. nov., type strain DSM 16338 T , isolated from Steinernema rarum .
Khuong B Nguyen - One of the best experts on this subject based on the ideXlab platform.
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Steinernema phyllophagae n sp rhabditida Steinernematidae a new entomopathogenic nematode from florida usa
Nematology, 2011Co-Authors: Khuong B Nguyen, Eileen A BussAbstract:A new species of entomopathogenic nematode, Steinernema phyllophagae n. sp., was isolated from a white grub (Phyllophaga sp.) in a live oak (Quercus virginiana) nursery. The new species is characterised by morphometrics of the infective Sjuvenile (IJ) with body length 1289 (1133-1395) μm, distance from anterior end to the excretory pore 99 (84-120) μm, tail 89 (77-109) μm, ratio a = 31 (27.6-35.5), H% = 57 (51-60) and E% = 110 (70-139). The pattern of the lateral field of IJ of the new species is 2, 5, 6, 8, 6, 2. The male of the first generation can be recognised by the length and shape of the spicule and gubernaculum, position of the excretory pore, D% = 75 (68-80), and GS% = 71 (61-77). The female can be recognised by the vulva having low epiptygma and by the presence of several papilla-like structures near the tail tip. Steinernema phyllophagae n. sp. differs further from other species of Steinernema by characteristics of ITS and D2D3 regions of rDNA.
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Steinernema citrae n sp rhabditida Steinernematidae a new entomopathogenic nematode from south africa
Nematology, 2011Co-Authors: N F Stokwe, Khuong B Nguyen, Antoinette P Malan, Rinus Knoetze, Louwrens R TiedtAbstract:During a survey for entomopathogenic nematodes in citrus orchards throughout South Africa, a new species of Steinernema was isolated from a citrus orchard on Rietkloof farm, near the town of Piketberg in the Western Cape Province, South Africa. The nematode was isolated from soil using the Galleria -baiting technique. Steinernema citrae n. sp. is characterised by the following morphological characters: third-stage infective juvenile with a body length of 754 (623-849) μ m, distance from head to excretory pore of 56 (49-64) μ m, tail length of 71 (63-81) μ m, and ratio E value of 110 (85-132). The lateral pattern for the new species is 2, 7, 8, 6, 4, 2 and is not typical for the genus. Steinernema citrae n. sp. is closely related the feltiae -group. The body length of the IJ is close to that of S. texanum and S. weiseri , though it differs in body diam., the length of the pharynx and E%. The male of S. citrae n. sp. differs from S. feltiae in the length and shape of the spicule and body diam. Steinernema citrae n. sp. differs from all species in the feltiae -group in the morphology of the vulva, as it has a single flapped, low, epiptygma. It also differs from the most closely related species, S. feltiae , as there is no interbreeding between the two species. In addition, the new nematode differs from other species of the feltiae -group by characteristics of the ITS and D2D3 regions of its rDNA.
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characterization of biocontrol traits in the entomopathogenic nematode heterorhabditis georgiana kesha strain and phylogenetic analysis of the nematode s symbiotic bacteria
Biological Control, 2009Co-Authors: David I Shapiroilan, Khuong B Nguyen, George N Mbata, Scott M Peat, Dana Blackburn, Byron J. AdamsAbstract:Abstract Our objective was to estimate the biocontrol potential of the recently discovered entomopathogenic nematode species Heterorhabditis georgiana (Kesha strain). Additionally, we conducted a phylogenetic characterization of the nematode’s symbiotic bacterium. In laboratory experiments, we compared H. georgiana to other entomopathogenic nematodes for virulence, environmental tolerance (to heat, desiccation, and cold), and host seeking ability. Virulence assays targeted Acheta domesticus, Agrotis ipsilon, Diaprepes abbreviatus, Musca domestica, Plodia interpunctella, Solenopsis invicta, and Tenebrio molitor. Each assay included H. georgiana and five or six of the following species: Heterorhabditis floridensis, Heterorhabditis indica, Heterorhabditis mexicana, Steinernema carpocapsae, Steinernema feltiae, Steinernema rarum, and Steinernema riobrave. Environmental tolerance assays included Heterorhabditis bacteriophora, H. georgiana, H. indica, S. carpocapsae, S. feltiae, and S. riobrave (except cold tolerance did not include S. carpocapsae or S. riobrave). Host seeking ability was assessed in H. bacteriophora, H. georgiana, S. carpocapsae, and Steinernema glaseri, all of which showed positive orientation to the host with S. glaseri having greater movement toward the host than S. carpocapsae (and the heterorhabditids being intermediate). Temperature range data (tested at 10, 13, 17, 25, 30 and 35 °C) indicated that H. georgiana can infect Galleria mellonella between 13 and 35 °C (with higher infection at 17–30 °C), and could reproduce between 17 and 30 °C (with higher nematode yields at 25 °C). Compared with other nematode species, H. georgiana expressed low or intermediate capabilities in all virulence and environmental tolerance assays indicating a relatively low biocontrol potential. Some novel observations resulted from comparisons among other species tested. In virulence assays, H. indica caused the highest mortality in P. interpunctella followed by S. riobrave; S. carpocapsae caused the highest mortality in A. domesticus followed by H. indica; and S. riobrave was the most virulent nematode to S. invicta. In cold tolerance, S. feltiae exhibited superior ability to cause mortality in G. mellonella (100%) at 10 °C, yet H. bacteriophora and H. georgiana exhibited the ability to produce attenuated infections at 10 °C, i.e., the infections resumed and produced mortality at 25 °C. In contrast, H. indica did not show an ability to cause attenuated infections. Based on the phylogenetic analysis, the bacterium associated with H. georgiana was identified as Photorhabdus luminescens akhurstii.
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entomopathogenic nematodes Steinernematidae and heterorhabditidae from the southwestern parts of south africa
African plant protection, 2006Co-Authors: Khuong B Nguyen, Matthew F AddisonAbstract:Malan A P, Nguye nKB&A ddison M F 2006. Entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) from the southwestern parts of South Africa. African Plant Protection 12: 65–69. Soil samples were collected in the southwestern parts of South Africa to obtain entomopathogenic nematodes of the families Steinernematidae and Heterorhabditidae. In total, 498 samples were randomly taken from cultivated and uncultivated habitats, including deciduous fruit orchards, vineyards and natural vegetation. Entomopathogenic nematodes were isolated from 36 samples (7 %) by baiting with larvae of Galleria mellonella (greater wax moth). Heterorhabditis was the dominant genus isolated, while Steinernema was rare. The most common species was Heterorhabditis bacteriophora Other species identified were Heterorhabditis zealandica and Steinernema khoisanae. The isolation of H. zealandica represents a new record for South Africa, whereas S. khoisanae has thus far been recorded only from South Africa. Entomopathogenic nematodes (EPNs) of the genera Steinernema and Heterorhabditis occur naturally in soil, where they parasitise different life stages of various soil-inhabiting insects. The nematodes are synergistically associated with bacteria and together they kill and utilise their insect host. Infective juveniles (IJs) are the only free-living stage in soil and carry the bacteria in their intestines, releasing them once the haemocoel of the host is penetrated. The IJ is a special third stage of development, highly resistant to adverse conditions in the soil, with some species capable of surviving for several months or even years without feeding. They kill their hosts within 1–2 days, can be produced commercially and can be applied with standard spraying equipment or through certain types of irrigation systems. The main interest in these nematodes is their potential as biological control agents in integrated pest management systems. The first record of EPNs in South Africa was from the maize beetle Heteronychus arator (Fabricius) (Heteronychus sanctae-helenae Blanch.) in Grahamstown, Eastern Cape Province (Harington 1953). Three isolates of Steinernema and a Heterorhabditis were evaluated in KwaZulu-Natal against the African sugarcane stalk-borer, Eldana saccharina Walker, in laboratory and field tests (Spaull 1988, 1990).A further survey was conducted in 1991 to obtain isolates more virulent against E. saccharina, during which seven Heterorhabditis and 15 Steinernema isolates were found (Spaull 1991), but they were not identified to species level. A new species of Steinernema for South Africa,
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laboratory evaluations of four entomopathogenic nematodes for control of subterranean termites isoptera rhinotermitidae
Environmental Entomology, 2002Co-Authors: Changlu Wang, Janine E Powell, Khuong B NguyenAbstract:Abstract The infectivity of four species of entomopathogenic nematodes, Steinernema carpocapsae (Weiser) [Breton strain], Steinernema riobrave Cabanillas, Poinar & Raulston [Weslaco strain], Heterorhabditis bacteriophora Poinar [HP88 strain], and Heterorhabditis indica Poinar, Karunakar & David [Coimbatore strain] was examined in the laboratory against two subterranean termites: Reticulitermes flavipes (Kollar) and Coptotermes formosanus Shiraki. In petri dish tests, they were all effective against C. formosanus at ≥400 nematodes per termite. Steinernema riobrave had no detectable effect against R. flavipes even at a rate of 2,000 nematodes per termite. The virulence of the nematodes for R. flavipes was H. indica > H. bacteriophora > S. carpocapsae > S. riobrave. The virulence of the nematodes for C. formosanus was H. indica and H. bacteriophora > S. carpocapsae and S. riobrave at α = 0.10 level. The LD50 of H. indica against R. flavipes in petri dishes and in containers with vermiculite/sand medium were ...
Sylvie Pages - One of the best experts on this subject based on the ideXlab platform.
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Entomopathogenic nematode-associated microbiota: from monoxenic paradigm to pathobiome
Microbiome, 2020Co-Authors: Jean-claude Ogier, Sylvie Pages, Marie Frayssinet, Sophie GaudriaultAbstract:BACKGROUND: The holistic view of bacterial symbiosis, incorporating both host and microbial environment, constitutes a major conceptual shift in studies deciphering host-microbe interactions. Interactions between Steinernema entomopathogenic nematodes and their bacterial symbionts, Xenorhabdus, have long been considered monoxenic two partner associations responsible for the killing of the insects and therefore widely used in insect pest biocontrol. We investigated this "monoxenic paradigm" by profiling the microbiota of infective juveniles (IJs), the soil-dwelling form responsible for transmitting Steinernema-Xenorhabdus between insect hosts in the parasitic lifecycle. RESULTS: Multigenic metabarcoding (16S and rpoB markers) showed that the bacterial community associated with laboratory-reared IJs from Steinernema carpocapsae, S. feltiae, S. glaseri and S. weiseri species consisted of several Proteobacteria. The association with Xenorhabdus was never monoxenic. We showed that the laboratory-reared IJs of S. carpocapsae bore a bacterial community composed of the core symbiont (Xenorhabdus nematophila) together with a frequently associated microbiota (FAM) consisting of about a dozen of Proteobacteria (Pseudomonas, Stenotrophomonas, Alcaligenes, Achromobacter, Pseudochrobactrum, Ochrobactrum, Brevundimonas, Deftia, etc.). We validated this set of bacteria by metabarcoding analysis on freshly sampled IJs from natural conditions. We isolated diverse bacterial taxa, validating the profile of the Steinernema FAM. We explored the functions of the FAM members potentially involved in the parasitic lifecycle of Steinernema. Two species, Pseudomonas protegens and P. chlororaphis, displayed entomopathogenic properties suggestive of a role in Steinernema virulence and membership of the Steinernema pathobiome. CONCLUSIONS: Our study validates a shift from monoxenic paradigm to pathobiome view in the case of the Steinernema ecology. The microbial communities of low complexity associated with EPNs will permit future microbiota manipulation experiments to decipher overall microbiota functioning in the infectious process triggered by EPN in insects and, more generally, in EPN ecology.
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xenorhabdus bovienii cs03 the bacterial symbiont of the entomopathogenic nematode Steinernema weiseri is a non virulent strain against lepidopteran insects
Journal of Invertebrate Pathology, 2015Co-Authors: Bernard Duvic, Alain Givaudan, Gaelle Bisch, John G Mcmullen, Patricia S Stock, Sylvie PagesAbstract:Xenorhabdus bacteria (γ-proteobacteria: Enterobacteriaceae) have dual lifestyles. They have a mutualistic relationship with Steinernema nematodes (Nematoda: Steinernematidae) and are pathogenic to a wide range of insects. Each Steinernema nematode associates with a specific Xenorhabdus species. However, a Xenorhabdus species can have multiple nematode hosts. For example, Xenorhabdus bovienii (Xb) colonizes at least nine Steinernema species from two different phylogenetic clades. The Steinernema–Xb partnership has been found in association with different insect hosts. Biological and molecular data on the Steinernema jollieti–Xb strain SS-2004 pair have recently been described. In particular, the Xb SS-2004 bacteria are virulent alone after direct injection into insect, making this strain a model for studying Xb virulence. In this study, we searched for Xb strains attenuated in virulence. For this purpose, we underwent infection assays with five Steinernema spp.–Xb pairs with two insects, Galleria mellonella (Lepidoptera: Pyralidae) and Spodoptera littoralis (Lepidoptera: Noctuidae). The S. weiseri–Xb CS03 pair showed attenuated virulence and lower fitness in S. littoralis in comparison to the other nematode-bacteria pairs. Furthermore, when injected alone into the hemolymph of G. mellonella or S. littoralis, the Xb CS03 bacterial strain was the only non-virulent strain. By comparison with the virulent Xb SS-2004 strain, Xb CS03 showed an increased sensitivity to the insect antimicrobial peptides, suggesting an attenuated response to the insect humoral immunity. To our current knowledge, Xb CS03 is the first non-virulent Xb strain identified. We propose this strain as a new model for studying the Xenorhabdus virulence.
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Draft Genome Sequence and Annotation of the Entomopathogenic Bacterium Xenorhabdus szentirmaii Strain DSM16338.
Genome Announcements, 2014Co-Authors: Maxime Gualtieri, Alain Givaudan, Sylvie Pages, Jean-claude Ogier, Sophie GaudriaultAbstract:We report the genome sequence of Xenorhabdus szentirmaii DSM16338 (4.84 Mb), a symbiont of the entomopathogenic nematode Steinernema rarum. This strain produces antimicrobial activity.
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Isolation and identification of entomopathogenic nematodes and their symbiotic bacteria from Herault and Gard (Southern France)
Journal of Invertebrate Pathology, 2008Co-Authors: Vanya Emelianoff, Nathalie Le Brun, Catherine Moulia, Sylvie Pages, Patricia Stock, Patrick Tailliez, Mathieu SicardAbstract:Isolation and identification of native nematode-bacterial associations in the field are necessary for successful control of endemic pests in a particular location. No study has yet been undertaken to recover and identify EPN in metropolitan France. In the present paper, we provide results of a survey of EPN and their symbiotic bacteria conducted in Herault and Gard regions in Southern France. Molecular characterization of isolated nematodes depicted three different Steinernema species and one Heterorhabditis species, H. bacteriophora. Steinernema species recovered were identified as: S. feltiae and S. affine and an undescribed species. Xenorhabdus symbionts were identified as X. bovienii for both S. feltiae and S. affine. Phylogenetic analysis placed the new undescribed Steinernema sp. as closely related to S. arenarium but divergent enough to postulate that it belongs to a new species within the "glaseri-group"., The Xenorhabdus symbiont from this Steinernema sp. was identified as X. kozodoii. All Heterorhabditis isolates recovered were diagnosed as H. bacteriophoro and their bacterial symbionts were identified as Photorhabdus luminescens. Molecular characterization of these nematodes enabled the distinction of two different H. bacteriophora strains. Bacterial symbiontic, strains of these two H. bacteriophora strains were identified as P. lurninescens ssp. kayaii and P. luminescens ssp. laumondii
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Effect of native Xenorhabdus on the fitness of their Steinernema hosts: contrasting types of interaction
Parasitology Research, 2003Co-Authors: Mathieu Sicard, Noël Boemare, Nathalie Le Brun, Bernard Godelle, Sylvie Pages, Catherine MouliaAbstract:Steinernema species are entomopathogenic nematodes. They are symbiotically associated with Enterobacteriaceae of the genus Xenorhabdus. These nematode–bacteria symbioses are extremely diversified and constitute an important new model in ecology and evolution to investigate symbioses between microbes and invertebrates. However, no study has so far adequately evaluated either the outcome of the interactions or the obligate nature of interactions in different Steinernema species in the same way. Studying three different species of Steinernema, we showed that symbiotic nematodes are always fitter than aposymbiotic ones. Nevertheless, we revealed contrasting types of interaction in terms of outcome and obligate nature of the interaction. Bacterial analyses showed that nematode species differed dramatically in the number of symbiotic Xenorhabdus they carried. We suggested that when the interaction appeared more facultative for a nematode species, the nematodes carried fewer Xenorhabdus cells than strongly dependent worm species. Thus, the symbiont transmission appeared to become more efficient as the relationship between the nematode and the bacteria became tighter.
Dawn H Gouge - One of the best experts on this subject based on the ideXlab platform.
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parasitism of subterranean termites isoptera rhinotermitidae termitidae by entomopathogenic nematodes rhabditida Steinernematidae heterorhabditidae
Journal of Economic Entomology, 2006Co-Authors: Dawn H Gouge, Paul B BakerAbstract:Abstract In laboratory bioassays, Steinernema riobrave Cabanillas, Poinar and Raulston (355 strain), Steinernema carpocapsae (Weiser) (Mexican 33 strain), Steinernema feltiae (Filipjev) (UK76 strain), and Heterorhabditis bacteriophora Poinar (HP88 strain) were all capable of infecting and killing three termite species, Heterotermes aureus (Snyder), Gnathamitermes perplexus (Banks), and Reticulitermes flavipes (Kollar) in laboratory sand assays. S. riobrave and S. feltiae caused low levels of Reticulitermes virginicus (Banks) mortality under the same conditions. At 22°C, significant mortality (≥80%) of worker H. aureus and G. perplexus was caused by S. riobrave, in sand assays, indicating the need for further study. Because of the short assay time (3 d maximum), reproduction of the nematodes in the target host species was not recorded. All nematode species were observed to develop to fourth-stage juveniles, preadult stages, or adults in all termite species with the exception of R. virginicus. Only S. riobr...
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temporal association of entomopathogenic nematodes rhabditida Steinernematidae and heterorhabditidae and bacteria
Journal of Invertebrate Pathology, 2006Co-Authors: Dawn H Gouge, Jennifer SnyderAbstract:Galleria mellonella L. larvae were infected with three species (seven strains) of Steinernema spp. or three species (three strains) of Heterorhabditis spp. Infected larvae were incubated at 22, 27, and 32 degrees C. Larvae were dorsally dissected every 6h over a 48-h period. Hemolymph was collected and streaked on tryptic soy agar plates. Several non-symbiotic bacterial species were identified from infected insect cadavers: Enterobacter gergoviae, Vibrio spp., Pseudomonas fluorescens type C, Serratia marcescens, Citrobacter freundii, and Serratia proteomaculans. At 18-24 h incubation, the nematode-associated symbiont occurred almost exclusively. Bacterial associates generally appeared outside the 18-24 h window. Infective juveniles of Steinernema feltiae (Filipjev) (27), Steinernema riobrave Cabanillas, Poinar, and Raulston (Oscar), or Steinernema carpocapsae (Weiser) (Kapow) were left untreated, or surface sterilized using thimerosal, then pipetted under sterile conditions onto tryptic soy agar plates. Several additional species of associated bacteria were identified using this method compared with the less extensive range of species isolated from infected G. mellonella. There was no difference in bacterial species identified from non-sterile or surface sterilized nematodes, suggesting that the bacteria identified originated from either inside the nematode or between second and third stage juvenile cuticles. Infective juveniles of S. feltiae (Cowles), S. carpocapsae (Cowles), and H. bacteriophora Poinar (Cowles) were isolated from field samples. Nematodes were surface-sterilized using sodium hypochlorite, mixed with G. mellonella hemolymph, and pipetted onto Biolog BUG (with blood) agar. Only the relevant symbionts were isolated from the limited number of samples available. The nematodes were then cultured in the laboratory for 14 months (sub-cultured in G. mellonella 7-times). Other Enterobacteriaceae could then be isolated from the Steinernematid nematodes including S. marcescens, Salmonella sp., and E. gergoviae, indicating the ability of the nematodes to associate with other bacteria in laboratory culture.
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parasitism of bark scorpion centruroides exilicauda scorpiones buthidae by entomopathogenic nematodes rhabditida Steinernematidae heterorhabditidae
Journal of Economic Entomology, 2005Co-Authors: Dawn H Gouge, Jennifer SnyderAbstract:In laboratory bioassays, Steinernema glaseri Steiner, Steinernema riobrave Cabanillas, Poinar & Raulston, Heterorhabditis bacteriophora Poinar, and Heterorhabditis marelatus Liu & Berry were capable of infecting and killing the bark scorpion, Centruroides exilicauda (Wood). Steinernema feltiae (Filipjev) and Steinernema carpocapsae (Weiser) failed to infect C. exilicauda at 22°C. S. glaseri, H. marelatus, and H. bacteriophora caused significant mortality at 22°C, indicating the potential role of these parasites as a biocontrol option. Efficacy of S. glaseri and H. bacteriophora was reduced in an assay conducted at 25°C. Only S. glaseri was able to reproduce in the target host. Dissection of scorpions at the end of the experimental periods revealed inactive juvenile S. riobrave, H. marelatus, and H. bacteriophora nematodes. Both mermithid and oxyurid nematodes have been documented as nematode parasites of scorpions, but rhabditids have not been reported until now. Field studies are warranted to assess the usefulness of entomopathogenic nematodes as biocontrol agents of bark scorpions.
