Zeitschriftenartikel: „Xenorhabdus“

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Rahoo, Ali Murad, Rehana Kanwal Rahoo, Muhammad Saeed, Muhammad Burhan und Nusrat Keerio. „MOLECULAR IDENTIFICATION AND GROWTH OF XENORHABDUS AND PHOTORHABDUS SYMBIONTS OF ENTOMOPATHOGENIC NEMATODES“. Plant Protection 6, Nr. 2 (23.08.2022): 91–100. http://dx.doi.org/10.33804/pp.006.02.4211.

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From the characterisation, the partial 16 S gene sequences obtained for the two bacteria were subjected to blast-bootstrap analysis to obtain the phylogenetic tree. In assessing the similarity of Xenorhabdus bovienii with five other Xenorhabdus spp., it was found to be 96% similar to X. nematophila and X. japonica with Accession Numbers D78006 and NR027194 respectively. The X. bovienii was closer to X. beddingii 95% and X. kazodoii and 97% similarity to X. poinarii. From the phylogenetic tree, the two species of bacteria were found to belong to the genera Xenorhabadus and Photorhabdus. The two bacteria were compared with Xenorhabdus japonica NR027194, X. nematophila, D78006 X. poinarii DQ211703, X. beddingii AY278675 and X. kozodoii Eu 190977. The results showed that at 20 ℃ both the bacteria X. bovienii and Photorhabdus luminescens increased to a log concentration of 7.5 after 6 h. They then increased slightly up to 15 h. At 25 ℃ X. bovienii had a concentration of 6.1 after 1 h but only increased slowly to 6.6 after 15 h. However, P. luminescens started with 5.6 after 1 h but increased smoothly to 7.5 after 15 h. X. bovienii and P. luminescens at 30 ℃ had a concentration of 6.2 after 1 h.

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Tailliez, Patrick, Sylvie Pagès, Nadège Ginibre und Noël Boemare. „New insight into diversity in the genus Xenorhabdus, including the description of ten novel species“. International Journal of Systematic and Evolutionary Microbiology 56, Nr. 12 (01.12.2006): 2805–18. http://dx.doi.org/10.1099/ijs.0.64287-0.

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We investigated the diversity of a collection of 76 Xenorhabdus strains, isolated from at least 27 species of Steinernema nematodes and collected in 32 countries, using three complementary approaches: 16S rRNA gene sequencing, molecular typing and phenotypic characterization. The 16S rRNA gene sequences of the Xenorhabdus strains were highly conserved (similarity coefficient >95 %), suggesting that the common ancestor of the genus probably emerged between 250 and 500 million years ago. Based on comparisons of the 16S rRNA gene sequences, we identified 13 groups and seven unique sequences. This classification was confirmed by analysis of molecular typing profiles of the strains, leading to the classification of new isolates into the Xenorhabdus species described previously and the description of ten novel Xenorhabdus species: Xenorhabdus cabanillasii sp. nov. (type strain USTX62T=CIP 109066T=DSM 17905T), Xenorhabdus doucetiae sp. nov. (type strain FRM16T=CIP 109074T=DSM 17909T), Xenorhabdus griffiniae sp. nov. (type strain ID10T=CIP 109073T=DSM 17911T), Xenorhabdus hominickii sp. nov. (type strain KE01T=CIP 109072T=DSM 17903T), Xenorhabdus koppenhoeferi sp. nov. (type strain USNJ01T=CIP 109199T=DSM 18168T), Xenorhabdus kozodoii sp. nov. (type strain SaVT=CIP 109068T=DSM 17907T), Xenorhabdus mauleonii sp. nov. (type strain VC01T=CIP 109075T=DSM 17908T), Xenorhabdus miraniensis sp. nov. (type strain Q1T=CIP 109069T=DSM 17902T), Xenorhabdus romanii sp. nov. (type strain PR06-AT=CIP 109070T=DSM 17910T) and Xenorhabdus stockiae sp. nov. (type strain TH01T=CIP 109067T=DSM 17904T). The Xenorhabdus strains studied here had very similar phenotypic patterns, but phenotypic features nonetheless differentiated the following species: X. bovienii, X. cabanillasii, X. hominickii, X. kozodoii, X. nematophila, X. poinarii and X. szentirmaii. Based on phenotypic analysis, we identified two major groups of strains. Phenotypic group GA comprised strains able to grow at temperatures of 35–42 °C, whereas phenotypic group GB comprised strains that grew at temperatures below 35 °C, suggesting that some Xenorhabdus species may be adapted to tropical or temperate regions and/or influenced by the growth and development temperature of their nematode host.

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Abd-Elgawad, Mahfouz M. M. „Xenorhabdus spp.: An Overview of the Useful Facets of Mutualistic Bacteria of Entomopathogenic Nematodes“. Life 12, Nr. 9 (31.08.2022): 1360. http://dx.doi.org/10.3390/life12091360.

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Mounting concern over the misuse of chemical pesticides has sparked broad interest for safe and effective alternatives to control plant pests and pathogens. Xenorhabdus bacteria, as pesticidal symbionts of the entomopathogenic nematodes Steinernema species, can contribute to this solution with a treasure trove of insecticidal compounds and an ability to suppress a variety of plant pathogens. As many challenges face sound exploitation of plant–phytonematode interactions, a full useful spectrum of such interactions should address nematicidal activity of Xenorhabdus. Steinernema–Xenorhabdus complex or Xenorhabdus individually should be involved in mechanisms underlying the favorable side of plant–nematode interactions in emerging cropping systems. Using Xenorhabdus bacteria should earnestly be harnessed to control not only phytonematodes, but also other plant pests and pathogens within integrated pest management plans. This review highlights the significance of fitting Xenorhabdus-obtained insecticidal, nematicidal, fungicidal, acaricidal, pharmaceutical, antimicrobial, and toxic compounds into existing, or arising, holistic strategies, for controlling many pests/pathogens. The widespread utilization of Xenorhabdus bacteria, however, has been slow-going, due to costs and some issues with their commercial processing. Yet, advances have been ongoing via further mastering of genome sequencing, discovering more of the beneficial Xenorhabdus species/strains, and their successful experimentations for pest control. Their documented pathogenicity to a broad range of arthropods and pathogens and versatility bode well for useful industrial products. The numerous beneficial traits of Xenorhabdus bacteria can facilitate their integration with other tactics for better pest/disease management programs.

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Lengyel, Katalin, Elke Lang, András Fodor, Emilia Szállás, Peter Schumann und Erko Stackebrandt. „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 28, Nr. 2 (März 2005): 115–22. http://dx.doi.org/10.1016/j.syapm.2004.10.004.

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Kuwata, Ryusei, Li-hong Qiu, Wen Wang, Yuki Harada, Mutsuhiro Yoshida, Eizo Kondo und Toyoshi Yoshiga. „Xenorhabdus ishibashii sp. nov., isolated from the entomopathogenic nematode Steinernema aciari“. International Journal of Systematic and Evolutionary Microbiology 63, Pt_5 (01.05.2013): 1690–95. http://dx.doi.org/10.1099/ijs.0.041145-0.

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Gram-negative bacteria of the genus Xenorhabdus exhibit a mutualistic association with steinernematid entomopathogenic nematodes and a pathogenic relationship with insects. Here we describe two isolates of the entomopathogenic nematode Steinernema aciari collected from China and Japan. 16S rRNA gene sequence similarity and phylogenetic analysis indicated that the isolates obtained from S. aciari belonged to the genus Xenorhabdus . Multilocus sequence analysis based on five universal protein-coding gene sequences revealed that the isolates were closely related to Xenorhabdus ehlersii DSM 16337T and Xenorhabdus griffiniae ID10T but that they exhibited <97 % sequence similarity with these reference strains, which indicated that the isolates were distinct from previously described species. Based on these genetic differences and several differential phenotypic traits, we propose that the isolates represent a novel species of the genus Xenorhabdus , for which we propose the name Xenorhabdus ishibashii sp. nov. The type strain is GDh7T ( = DSM 22670T = CGMCC 1.9166T).

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GREWAL, P. S., M. MATSUURA und V. CONVERSE. „Mechanisms of specificity of association between the nematode Steinernema scapterisci and its symbiotic bacterium“. Parasitology 114, Nr. 5 (Mai 1997): 483–88. http://dx.doi.org/10.1017/s0031182096008669.

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We suggest a new mechanism for the maintenance of specificity of the association between the entomopathogenic nematode Steinernema scapterisci and its symbiotic bacteria. We evaluated the development and reproduction of infective and non-infective juvenile S. scapterisci in monoxenic combinations with its symbiotic bacteria, Xenorhabdus sp. ‘S’ and with the bacterial symbiont of Steinernema carpocapsae and Steinernema riobravis. Although development of non-infective stages occurred on all Xenorhabdus spp., the development of infective juveniles to the 4th stage (‘dauer’ recovery) was significantly delayed and reduced with X. nematophilus and Xenorhabdus sp. ‘R’, the bacterial symbionts of S. carpocapsae and S. riobravis, respectively. ‘Dauer’ recovery improved significantly when the cultures of X. nematophilus and Xenorhabdus sp. ‘R’ were supplemented with cell-free filtrates from Xenorhabdus sp. ‘S’. The infective juvenile S. scapterisci produced in all 3 cultures were virulent to Galleria mellonella larvae, confirming successful retention of Xenorhabdus from other steinernematids in their intestine. In fact, S. scapterisci infective juveniles containing X. nematophilus or Xenorhabdus sp. ‘R’ were more virulent to G. mellonella than those containing their natural symbiont, Xenorhabdus sp. ‘S’. We believe that this is the first demonstration of the symbiont-specific exit of infective juveniles from the ‘dauer’ phase which represents the finest level of specificity of bacteria–nematode association. This is also the first report of successful isolation of the natural symbiont of S. scapterisci.

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Harahap, Mardianto, und Didik Sulistyanto. „Karakteristik morfologi dan fisiologi beberapa isolat lokal bakteri simbiose nematoda entomopatogen kompleks serta uji virulensi pada larva Plutella xylostella“. Jurnal Entomologi Indonesia 1, Nr. 1 (23.02.2017): 41. http://dx.doi.org/10.5994/jei.1.1.41.

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Local isolates of entomopathogenic nematodes are symbiotically associated with bacteria of the genus Xenorhabdus or Photorhabdus. Symbiont bacteria isolated from local isolates of entomopathogenic nematode (Pujon, Cemoro Lawang and X. nematophilus) were identical with Xenorhabdus spp and isolate of Ngadas was identical with Photorhabdus luminescens. Some isolates, such as Xenorhabdus (isolate of Pujon) and P. luminescens (isolate of Ngadas) has a high virulence when the bacteria was injected into insect haemocoel. High virulence was indicated by Xenorhabdus nematophilus when it was applied orally.

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Lengyel, Katalina, Elke Lang, Andras Fodor, Emilia Szallas, Peter Schumann und Erko Stackebrandt. „Erratum to “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 30, Nr. 1 (Januar 2007): 83. http://dx.doi.org/10.1016/j.syapm.2006.11.003.

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Cao, Li, Xuehong Qiu, Xiaofen Liu, Xiuling Liu und Richou Han. „Nutrient potential of various Xenorhabdus and Photorhabdus bacteria for a free-living nematode Panagrellus redivivus“. Nematology 10, Nr. 1 (2008): 79–85. http://dx.doi.org/10.1163/156854108783360104.

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Abstract Xenorhabdus and Photorhabdus bacteria are symbionts of entomopathogenic nematodes of the genera Steinernema and Heterorhabditis, respectively. To determine the nutrient potential of these bacteria for a free-living nematode, Panagrellus redivivus, a promising food source for first-feeding fish and crustacean, sterile first-stage juveniles (J1) of P. redivivus were fed on various isolates of Xenorhabdus and Photorhabdus bacteria in liquid cultures. Most of the tested bacterial isolates did not support the growth of P. redivivus. However, four of the Xenorhabdus isolates (X. nematophila All, X. bovienii T319, X. beddingii X-7 and X. poinarii KG) provided nutrients for the production of these nematodes in a liquid medium. Two Xenorhabdus isolates (X. beddingii X-7 and X. poinarii KG) even supported mass production of the nematode in a sponge medium, with yields comparable to those with yeast strains. This is the first report that Xenorhabdus bacteria can function as a nutrient source for mass production of nematodes other than their usual symbiotic partners.

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Eidt, D. C., und J. G. Stewart. „EFFECT ON GROWTH AND ROOT NODULATION OF CLOVERS, TRIFOLIUM SPP., BY GALLERIA MELLONELLA (L.) (LEPIDOPTERA: PYRALIDAE) INFECTED WITH STEINERNEMA CARPOCAPSAE (WEISER) (RHABDITA: STEINERNEMATIDAE) AND ITS SYMBIONT, XENORHABDUS NEMATOPHILUS POINAR AND THOMAS“. Canadian Entomologist 129, Nr. 2 (April 1997): 205–10. http://dx.doi.org/10.4039/ent129205-2.

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AbstractRed and white clovers, Trifolium spp., were grown in nitrogen-poor soil containing cadavers of larval Galleria mellonella (L.) that were infected with Steinernema carpocapsae (Weiser) and its symbiont Xenorhabdus nematophilus Poinar and Thomas. Growth and root nodulation were not affected by the nematode treatment, leading us to conclude that they would not be impaired through the action of antimicrobial agents produced by Xenorhabdus spp. present in soils because of Xenorhabdus-infected insect cadavers.

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Boemare, N. E., M. H. Boyer-Giglio, J. O. Thaler, R. J. Akhurst und M. Brehelin. „Lysogeny and bacteriocinogeny in Xenorhabdus nematophilus and other Xenorhabdus spp.“ Applied and Environmental Microbiology 58, Nr. 9 (1992): 3032–37. http://dx.doi.org/10.1128/aem.58.9.3032-3037.1992.

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He, Hongjun, Roger Gordon und John A. Gow. „Phenotypic characterization of the Xenorhabdus bacterial symbiont of a Texas strain of the entomopathogenic nematode Steinernema riobrave, and characterization of the Xenorhabdus bovienii bacterial symbiont of a Newfoundland strain of Steinernema feltiae“. Canadian Journal of Microbiology 46, Nr. 7 (01.07.2000): 618–22. http://dx.doi.org/10.1139/w00-036.

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Two bacterial symbionts of entomopathogenic nematodes, one of which originated from Texas, U.S.A., and the other from Newfoundland, Canada, were characterized phenotypically. These strains belonged to the genus Xenorhabdus. The Newfoundland (NF) strain was shown to be X. bovienii but the Texas (TX) strain was not identified at the species level. Four additional cultures of Xenorhabdus were included in the study. These were a strain of X. bovienii (Umeå), which was from a nematode of European origin, and strains of X. nematophilus, X.beddingii, and X.poinarii. The tests used in this study indicated identical properties for the NF (North American) and Umeå (European) strains of X. bovienii. These could be differentiated from the other strains studied by their failure to grow at 34°C and resistance to low concentrations of a mixture of amoxilline and clavulanic acid. The Xenorhabdus TX strain could be differentiated from the other strains studied by its failure to grow at 10°C. Of the tests done, approximately 30 were useful in distinguishing between the strains and species studied.Key words: symbionts, nematode, Steinernema, Xenorhabdus, Xenorhabdus bovienii.

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Ferreira, Tiarin, Carol A. van Reenen, Akihito Endo, Cathrin Spröer, Antoinette P. Malan und Leon M. T. Dicks. „Description of Xenorhabdus khoisanae sp. nov., the symbiont of the entomopathogenic nematode Steinernema khoisanae“. International Journal of Systematic and Evolutionary Microbiology 63, Pt_9 (01.09.2013): 3220–24. http://dx.doi.org/10.1099/ijs.0.049049-0.

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Bacterial strain SF87T, and additional strains SF80, SF362 and 106-C, isolated from the nematode Steinernema khoisanae, are non-bioluminescent Gram-reaction-negative bacteria that share many of the carbohydrate fermentation reactions recorded for the type strains of recognized Xenorhabdus species. Based on 16S rRNA gene sequence data, strain SF87T is shown to be closely related (98 % similarity) to Xenorhabdus hominickii DSM 17903T. Nucleotide sequences of strain SF87 obtained from the recA, dnaN, gltX, gyrB and infB genes showed 96–97 % similarity with Xenorhabdus miraniensis DSM 17902T . However, strain SF87 shares only 52.7 % DNA–DNA relatedness with the type strain of X. miraniensis , confirming that it belongs to a different species. Strains SF87T, SF80, SF362 and 106-C are phenotypically similar to X. miraniensis and X. beddingii , except that they do not produce acid from aesculin. These strains are thus considered to represent a novel species of the genus Xenorhabdus , for which the name Xenorhabdus khoisanae sp. nov. is proposed. The type strain is SF87T ( = DSM 25463T = ATCC BAA-2406T).

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Thappeta, Kishore Reddy Venkata, Kristin Ciezki, Nydia Morales-Soto, Shane Wesener, Heidi Goodrich-Blair, S. Patricia Stock und Steven Forst. „R-type bacteriocins of Xenorhabdus bovienii determine the outcome of interspecies competition in a natural host environment“. Microbiology 166, Nr. 11 (01.12.2020): 1074–87. http://dx.doi.org/10.1099/mic.0.000981.

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Xenorhabdus species are bacterial symbionts of Steinernema nematodes and pathogens of susceptible insects. Different species of Steinernema nematodes carrying specific species of Xenorhabdus can invade the same insect, thereby setting up competition for nutrients within the insect environment. While Xenorhabdus species produce both diverse antibiotic compounds and prophage-derived R-type bacteriocins (xenorhabdicins), the functions of these molecules during competition in a host are not well understood. Xenorhabdus bovienii (Xb-Sj), the symbiont of Steinernema jollieti, possesses a remnant P2-like phage tail cluster, xbp1, that encodes genes for xenorhabdicin production. We show that inactivation of either tail sheath (xbpS1) or tail fibre (xbpH1) genes eliminated xenorhabdicin production. Preparations of Xb-Sj xenorhabdicin displayed a narrow spectrum of activity towards other Xenorhabdus and Photorhabdus species. One species, Xenorhabdus szentirmaii (Xsz-Sr), was highly sensitive to Xb-Sj xenorhabdicin but did not produce xenorhabdicin that was active against Xb-Sj. Instead, Xsz-Sr produced high-level antibiotic activity against Xb-Sj when grown in complex medium and lower levels when grown in defined medium (Grace’s medium). Conversely, Xb-Sj did not produce detectable levels of antibiotic activity against Xsz-Sr. To study the relative contributions of Xb-Sj xenorhabdicin and Xsz-Sr antibiotics in interspecies competition in which the respective Xenorhabdus species produce antagonistic activities against each other, we co-inoculated cultures with both Xenorhabdus species. In both types of media Xsz-Sr outcompeted Xb-Sj, suggesting that antibiotics produced by Xsz-Sr determined the outcome of the competition. In contrast, Xb-Sj outcompeted Xsz-Sr in competitions performed by co-injection in the insect Manduca sexta, while in competition with the xenorhabdicin-deficient strain (Xb-Sj:S1), Xsz-Sr was dominant. Thus, xenorhabdicin was required for Xb-Sj to outcompete Xsz-Sr in a natural host environment. These results highlight the importance of studying the role of antagonistic compounds under natural biological conditions.

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Cowles, Charles E., und Heidi Goodrich-Blair. „The Xenorhabdus nematophila nilABC Genes Confer the Ability of Xenorhabdus spp. To Colonize Steinernema carpocapsae Nematodes“. Journal of Bacteriology 190, Nr. 12 (04.04.2008): 4121–28. http://dx.doi.org/10.1128/jb.00123-08.

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ABSTRACT Members of the Steinernema genus of nematodes are colonized mutualistically by members of the Xenorhabdus genus of bacteria. In nature, Steinernema carpocapsae nematodes are always found in association with Xenorhabdus nematophila bacteria. Thus, this interaction, like many microbe-host associations, appears to be species specific. X. nematophila requires the nilA, nilB, and nilC genes to colonize S. carpocapsae. In this work, we showed that of all the Xenorhabdus species examined, only X. nematophila has the nilA, nilB, and nilC genes. By exposing S. carpocapsae to other Xenorhabdus spp., we established that only X. nematophila is able to colonize S. carpocapsae; therefore, the S. carpocapsae-X. nematophila interaction is species specific. Further, we showed that introduction of the nilA, nilB, and nilC genes into other Xenorhabdus species enables them to colonize the same S. carpocapsae host tissue that is normally colonized by X. nematophila. Finally, sequence analysis supported the idea that the nil genes were horizontally acquired. Our findings indicate that a single genetic locus determines host specificity in this bacteria-animal mutualism and that host range expansion can occur through the acquisition of a small genetic element.

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Karthikeyan, S., T. Abdul Razak, A. Manivannan, S. Sekar und P. K. Muthukumar. „Virulence of Xenorhabdus bovienii and Xenorhabdus japonica Against Cnaphalocrocis medinalis Guenee“. Madras Agricultural Journal 104, Nr. 10-12 (01.12.2017): 359. http://dx.doi.org/10.29321/maj.2017.000078.

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Sajnaga, Ewa, und Waldemar Kazimierczak. „Evolution and taxonomy of nematode-associated entomopathogenic bacteria of the genera Xenorhabdus and Photorhabdus: an overview“. Symbiosis 80, Nr. 1 (Januar 2020): 1–13. http://dx.doi.org/10.1007/s13199-019-00660-0.

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AbstractEntomopathogenic bacteria from the genera Photorhabdus and Xenorhabdus are closely related Gram-negative bacilli from the family Enterobacteriaceae (γ-Proteobacteria). They establish obligate mutualistic associations with soil nematodes from the genera Steinernema and Heterorhabditis to facilitate insect pathogenesis. The research of these two bacterial genera is focused mainly on their unique interactions with two different animal hosts, i.e. nematodes and insects. So far, studies of the mutualistic bacteria of nematodes collected from around the world have contributed to an increase in the number of the described Xenorhabdus and Photorhabdus species. Recently, the classification system of entomopatogenic nematode microsymbionts has undergone profound revision and now 26 species of the genus Xenorhabdus and 19 species of the genus Photorhabdus have been identified. Despite their similar life style and close phylogenetic origin, Photorhabdus and Xenorhabdus bacterial species differ significantly in e.g. the nematode host range, symbiotic strategies for parasite success, and arrays of released antibiotics and insecticidal toxins. As the knowledge of the diversity of entomopathogenic nematode microsymbionts helps to enable the use thereof, assessment of the phylogenetic relationships of these astounding bacterial genera is now a major challenge for researchers. The present article summarizes the main information on the taxonomy and evolutionary history of Xenorhabdus and Photorhabdus, entomopathogenic nematode symbionts.

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Burgettiné Böszörményi, Erzsébet, István Barcs, Gyula Domján, Katalin Bélafiné Bakó, András Fodor, László Makrai und Dávid Vozik. „A Xenorhabdus budapestensis entomopatogén baktérium sejtmentes fermentlevének és tisztítottfehérje-frakciójának antimikrobiális hatása néhány zoonoticus baktériumra“. Orvosi Hetilap 156, Nr. 44 (November 2015): 1782–86. http://dx.doi.org/10.1556/650.2015.30274.

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Introduction: Many multi-resistant patogens appear continuously resulting in a permanent need for the development of novel antibiotics. A large number of antibiotics introduced in clinical and veterinary practices are not effective. Antibacterial peptides with unusual mode of action may represent a promising option against multi-resistant pathogens. The entomopathogenic Xenorhabdus budapestensis bacteria produce several different antimicrobial peptides compounds such as bicornutin-A and fabclavin. Aim: The aim of the authors was to evaluate the in vitro antibacterial effect of Xenorhabdus budapestensis using zoonotic patogen bacteria. Method: Cell-free conditioned media and purified peptide fractions of Xenorhabdus budapestensis were tested on Gram-positive (Rhodococcus equi, Erysipelothrix rhusiopathia, Staphylococcus aureus, Streptococcus equi, Corynebacterium pseudotuberculosis, Listeria monocytagenes) and Gram-negative bacteria (Salmonella gallinarum, Salmonella derbi, Bordatella bronchoseptica, Escherichia coli, Pasteurella multocida, Aeromonas hydrophila) using agar diffusion test on blood agar plates. Results: It was found that Xenorhabdus budapestensis bacteria produced compounds with strong and dose-dependent effects on the tested organisms. Purified peptid fraction exerted a more marked effect than cell free conditioned media. Gram-positive bacteria were more sensitive to this antibacterial effect than Gram-negative bacteria. Conclusions: Antibacterial peptide compound from Xenorhabdus budapestensis exert marked antibacterial effect on zoonotic patogen bacteria and they should be further evaluated in future for their potential use in the control or prevention of zoonoses. Orv. Hetil., 2015, 156(44), 1782–1786.

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Tailliez, Patrick, Sylvie Pagès, Steve Edgington, Lukasz M. Tymo und Alan G. Buddie. „Description of Xenorhabdus magdalenensis sp. nov., the symbiotic bacterium associated with Steinernema australe“. International Journal of Systematic and Evolutionary Microbiology 62, Pt_8 (01.08.2012): 1761–65. http://dx.doi.org/10.1099/ijs.0.034322-0.

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A symbiotic bacterium, strain IMI 397775T, was isolated from the insect-pathogenic nematode Steinernema australe. On the basis of 16S rRNA gene sequence similarity, this bacterial isolate was shown to belong to the genus Xenorhabdus , in agreement with the genus of its nematode host. The accurate phylogenetic position of this new isolate was defined using a multigene approach and showed that isolate IMI 397775T shares a common ancestor with Xenorhabdus doucetiae FRM16T and Xenorhabdus romanii PR06-AT, the symbiotic bacteria associated with Steinernema diaprepesi and Steinernema puertoricense, respectively. The nucleotide identity (less than 97 %) between isolate IMI 397775T, X. doucetiae FRM16T and X. romanii PR06-AT calculated for the concatenated sequences of five gene fragments encompassing 4275 nt, several phenotypic traits and the difference between the upper temperatures that limit growth of these three bacteria allowed genetic and phenotypic differentiation of isolate IMI 397775T from the two closely related species. Strain IMI 397775T therefore represents a novel species, for which the name Xenorhabdus magdalenensis sp. nov. is proposed, with the type strain IMI 397775T ( = DSM 24915T).

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CLARKE, DAVID J., und BARBARA C. A. DOWDS. „Pathogenicity of Xenorhabdus luminescens“. Biochemical Society Transactions 20, Nr. 1 (01.02.1992): 65S. http://dx.doi.org/10.1042/bst020065s.

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Xu, J., S. Lohrke, I. M. Hurlbert und R. E. Hurlbert. „Transformation of Xenorhabdus nematophilus.“ Applied and Environmental Microbiology 55, Nr. 4 (1989): 806–12. http://dx.doi.org/10.1128/aem.55.4.806-812.1989.

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Grewal, Parwinder S., Edwin E. Lewis und Sudha Venkatachari. „Allelopathy: a possible mechanism of suppression of plant-parasitic nematodes by entomopathogenic nematodes“. Nematology 1, Nr. 7 (1999): 735–43. http://dx.doi.org/10.1163/156854199508766.

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Abstract A possible mechanism of suppression of a plant-parasitic nematode Meloidogyne incognita by entomopathogenic nematodes is described. Heat-killed entomopathogenic nematodes Steinernema feltiae and S. riobrave temporarily suppressed penetration of the root-knot nematode M. incognita into tomato roots, but live nematodes had no effect. Infective juvenile M. incognita were repelled from all entomopathogenic nematode treatments that included their symbiotic bacteria. They were repelled by Galleria mellonella cadavers infected with S. carpocapsae, S. feltiae, and S. riobrave and from cell-free culture filtrates of the symbiotic bacteria Xenorhabdus nematophilus, X. bovienii, and Xenorhabdus sp. "R" from the three nematode species, respectively. Cell-free filtrates from all three Xenorhabdus spp. were toxic to M. incognita infective juveniles causing 98-100% mortality at 15% concentration. Cell-free filtrate of Xenorhabdus sp. "R" also reduced the hatch of M. incognita eggs. Application of formulated bacterial cell-free filtrates temporarily suppressed M. incognita penetration into tomato roots in a greenhouse trial. The short-term effects of cell-free bacterial filtrates, namely toxicity and repellency, were almost entirely due to ammonium. These results demonstrate allelopathic interactions between plant-parasitic nematodes, entomopathogenic nematodes and their symbiotic bacteria. The likely role of allelopathy in the suppression of plant-parasitic nematodes by innundative applications of entomopathogenic nematodes is discussed. Allelopathie: Ein moglicher Mechanismus zur Unterdruckung pflanzenparasitarer Nematoden durch insektenpathogene Nematoden - Es wird ein moglicher Mechanismus zur Unterdruckung des pflanzenparasitaren Nematoden Meloidogyne incognita durch insektenpathogene Nematoden beschrieben. Durch Hitze abgetotete insektenpathogene Nematoden Steinernema feltiae und S. riobrave underdruckten das Eindringen des Wurzelgallenalchens M. incognita in Tomatenwurzeln, lebende Nematoden hatten keine Wirkung. Infektionsjuvenile von M. incognita wurden von allen Behandlungen mit insektenpathogenen Nematoden abgestossen, die auch die symbiontischen Bakterien einschlossen. Sie wurden durch die Kadaver von Galleria mellonella abgestossen, die mit S. carpocapsae, S. feltiae und S. riobrave infiziert waren sowie durch zellfreie Kultursubstrate der symbiontischen Bakterien Xenorhabdus nematophilus, X. bovienii und Xenorhabdus sp. "R" aus den drei genannten Nematodenarten. Zellfreie Kultursubstrate von allen drei Xenorhabdus spp. waren giftig fur die Infektionsjuvenilen von M. incognita und verursachten in einer Konzentration von 15% Abtotungsraten von 98-100%. Zellfreie Kultursubstrate von Xenorhabdus sp. "R" vermiderten ausserdem das Schlupfen von M. incognita-Eiern. In einem Gewachshausversuch unterdruckten formulierte zellfreie Bakterienfiltrate vorubergehend das Eindringen von M. incognita in Tomatenwurzeln. Die Kurzzeitwirkungen von zellfreien Bakterien filtraten, namentlich Giftigkeit und Abstossung, waren nahezu ganz bedingt durch Ammoniak. Diese Ergebnisse zeigen das Vorhandensein von allelopathischen Wechselwirkungen zwischen pflanzenparasitaren Nematoden, insektenpathogenen Nematoden und deren symbiontischen Bakterien. Die wahrscheinliche Rolle von Allelopathie bei der Unterdruckung pflanzenparasitarer Nematoden durch eine Massenanwendung insektenpathogener Nematoden wird diskutiert.

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He, Hongjun, Roger Gordon und John A. Gow. „The effect of temperature on the fatty acids and isozymes of a psychrotrophic and two mesophilic species ofXenorhabdus, a bacterial symbiont of entomopathogenic nematodes“. Canadian Journal of Microbiology 47, Nr. 5 (01.05.2001): 382–91. http://dx.doi.org/10.1139/w01-025.

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In the first part of this study, generation times relative to temperature, together with cardinal and conceptual temperatures, were determined for four strains of Xenorhabdus bacteria that represented three geographically distinct species. The data showed that the NF strain of Xenorhabdus bovienii, like the Umeå strain of the same species, is psychrotrophic, while Xenorhabdus sp. TX strain resembles Xenorhabdus nematophila All strain in being mesophilic. In the second part, the capacity of these bacteria to adapt to changes in temperature, shown by changes in fatty acid composition, was investigated. As temperature declined, the proportions of the two major unsaturated fatty acids, palmitoleic (16:1ω7) acid and oleic (18:1ω9) acid, increased significantly in all of the strains. The proportion of the prevalent saturated fatty acid, which was palmitic acid (16:0), decreased. In the All, NF, and Umeå strains, myristic acid (14:0), margaric acid (17:0), cyclopropane (17:0c), and arachidic acid (20:0) decreased with decreasing temperature. In the third part of the study, the synthesis of isozymes in response to changing temperature was investigated. For the seven enzymes studied, the numbers for which isozyme synthesis was temperature related were as follows: five for Umeå, four for All, three for NF, and two for TX. Where the study dealt with fatty acid composition and isozyme synthesis, the results show a broad capacity for physiological temperature adaptation among strains of different climatic origin.Key words: Xenorhabdus, temperature, psychrotroph, mesophile, fatty acid, isozyme.

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Palma, Leopoldo, Laureano Frizzo, Sebastian Kaiser, Colin Berry, Primitivo Caballero, Helge B. Bode und Eleodoro Eduardo Del Valle. „Genome Sequence Analysis of Native Xenorhabdus Strains Isolated from Entomopathogenic Nematodes in Argentina“. Toxins 16, Nr. 2 (17.02.2024): 108. http://dx.doi.org/10.3390/toxins16020108.

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Entomopathogenic nematodes from the genus Steinernema (Nematoda: Steinernematidae) are capable of causing the rapid killing of insect hosts, facilitated by their association with symbiotic Gram-negative bacteria in the genus Xenorhabdus (Enterobacterales: Morganellaceae), positioning them as interesting candidate tools for the control of insect pests. In spite of this, only a limited number of species from this bacterial genus have been identified from their nematode hosts and their insecticidal properties documented. This study aimed to perform the genome sequence analysis of fourteen Xenorhabdus strains that were isolated from Steinernema nematodes in Argentina. All of the strains were found to be able of killing 7th instar larvae of Galleria mellonella (L.) (Lepidoptera: Pyralidae). Their sequenced genomes harbour 110 putative insecticidal proteins including Tc, Txp, Mcf, Pra/Prb and App homologs, plus other virulence factors such as putative nematocidal proteins, chitinases and secondary metabolite gene clusters for the synthesis of different bioactive compounds. Maximum-likelihood phylogenetic analysis plus average nucleotide identity calculations strongly suggested that three strains should be considered novel species. The species name for strains PSL and Reich (same species according to % ANI) is proposed as Xenorhabdus littoralis sp. nov., whereas strain 12 is proposed as Xenorhabdus santafensis sp. nov. In this work, we present a dual insight into the biocidal potential and diversity of the Xenorhabdus genus, demonstrated by different numbers of putative insecticidal genes and biosynthetic gene clusters, along with a fresh exploration of the species within this genus.

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Fallon, Declan, Harry Kaya, Randy Gaugler und Brent Sipes. „Effect of Steinernema feltiae-Xenorhabdus bovienii insect pathogen complex on Meloidogyne javanica“. Nematology 6, Nr. 5 (2004): 671–80. http://dx.doi.org/10.1163/1568541042843496.

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AbstractIsolates of Steinernema feltiae MG-14 from Hawaii and SN from France, and the symbiont Xenorhabdus bovienii from each nematode isolate, were tested for their glasshouse efficacy against the root-knot nematode, Meloidogyne javanica, on several vegetable plants. Steinernema feltiae application for 3-5 consecutive days at rates of 1000 or 10 000 infective juveniles (IJ) did not affect M. javanica root penetration and development in glasshouse pot experiments. IJ were recovered from the cortical tissue of tomatoes, soybeans, snow peas and cow peas. Xenorhabdus bovienii applied at 1010 colony-forming units (CFU) ml–1 reduced root-knot nematode penetration in cow peas but was ineffective in tomato or snow pea. Xenorhabdus bovienii metabolites had no effect on M. javanica root penetration and egg production in soybean. Soybean plant growth was unaffected by nematode and bacterial treatment; biomass was lower in M. javanica-infected soybean, irrespective of treatment, than in non-infected soybean, but the differences between the treatments were non-significant. Accordingly, the Steinernema feltiae-Xenorhabdus bovienii complex did not meet the objective for the suppression of M. javanica root penetration and development.

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Kämpfer, Peter, Nicholas J. Tobias, Long Phan Ke, Helge B. Bode und Stefanie P. Glaeser. „Xenorhabdus thuongxuanensis sp. nov. and Xenorhabdus eapokensis sp. nov., isolated from Steinernema species“. International Journal of Systematic and Evolutionary Microbiology 67, Nr. 5 (01.05.2017): 1107–14. http://dx.doi.org/10.1099/ijsem.0.001770.

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Thanwisai, Aunchalee, Paramaporn Muangpat, Abdulhakam Dumidae, Chanakan Subkrasae, Jiranun Ardpairin, Sarunporn Tandhavanant und Apichat Vitta. „Identification of entomopathogenic nematodes and their symbiotic bacteria in national parks of Thailand, and mosquitocidal activity of Xenorhabdus griffiniae against Aedes aegypti larvae“. Nematology 24, Nr. 2 (03.09.2021): 193–203. http://dx.doi.org/10.1163/15685411-bja10124.

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Summary Entomopathogenic nematodes (EPN) Steinernema and Heterorhabditis with symbionts with Xenorhabdus and Photorhabdus bacteria, respectively, are reported as biocontrol agents for insect control. The objectives of this study were to identify EPN and their symbiotic bacteria in national parks of Phitsanulok Province, Thailand, and to test how Xenorhabdus isolates attack Aedes aegypti larvae. We collected 810 soil samples from four national parks. The juvenile stage of EPN was isolated from soil samples using a baiting technique with Galleria mellonella followed by a White trap. Partial regions of 28S rDNA and internal transcript spacer were sequenced to identify EPN, and recA sequencing was used to discriminate between Xenorhabdus and Photorhabdus. We found that 74 of the 810 soil samples (9.1%) were positive for the EPN. The EPN were molecularly identified as S. surkhetense, S. longicaudum, H. indica and Heterorhabditis sp. SGmg3, and their symbiotic bacteria were identified as X. stockiae, X. griffiniae, X. indica, X. vietnamensis, P. luminescens subsp. akhurstii, and P. temperata subsp. temperata. Xenorhabdus griffiniae showed potential larvicidal activity against A. aegypti (91% mortality at 72 and 96 h after exposure). This study demonstrates the diversity of EPN and symbiotic bacteria in national parks of Thailand and the potential to use X. griffiniae as a biocontrol agent to kill A. aegypti larvae.

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Thaler, Jacques-Olivier, Bernard Duvic, Alain Givaudan und Noël Boemare. „Isolation and Entomotoxic Properties of theXenorhabdus nematophilus F1 Lecithinase“. Applied and Environmental Microbiology 64, Nr. 7 (01.07.1998): 2367–73. http://dx.doi.org/10.1128/aem.64.7.2367-2373.1998.

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ABSTRACT Xenorhabdus spp. and Photorhabdus spp., entomopathogenic bacteria symbiotically associated with nematodes of the families Steinernematidae and Heterorhabditidae, respectively, were shown to produce different lipases when they were grown on suitable nutrient agar. Substrate specificity studies showed thatPhotorhabdus spp. exhibited a broad lipase activity, while most of the Xenorhabdus spp. secreted a specific lecithinase. Xenorhabdus spp. occur spontaneously in two variants, phase I and phase II. Only the phase I variants ofXenorhabdus nematophilus and Xenorhabdus bovienii strains produced lecithinase activity when the bacteria were grown on a solid lecithin medium (0.01% lecithin nutrient agar; 24 h of growth). Five enzymatic isomers responsible for this activity were separated from the supernatant of a X. nematophilus F1 culture in two chromatographic steps, cation-exchange chromatography and C18 reverse-phase chromatography. The substrate specificity of the X. nematophilus F1 lecithinase suggested that a phospholipase C preferentially active on phosphatidylcholine could be isolated. The entomotoxic properties of each isomer were tested by injection into the hemocoels of insect larvae. None of the isomers exhibited toxicity with the insects tested, Locusta migratoria, Galleria mellonella, Spodoptera littoralis, and Manduca sexta. The possible role of lecithinase as either a virulence factor or a symbiotic factor is discussed.

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ULUĞ, Derya. „Rattus norvegicus (Berkenhout, 1769) (Rodentia: Muridae)’un entomopatojen bakteriler ile enfekte böcek kadavralarına tepkisinin belirlenmesi“. Turkish Journal of Entomology 47, Nr. 1 (16.04.2023): 51–58. http://dx.doi.org/10.16970/entoted.1199313.

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Xenorhabdus Thomas & Poinar (Enterobacterales: Morganellaceae) and Photorhabdus Thomas & Poinar (Enterobacterales: Morganellaceae) bacteria are mutualistically associated with Steinernema Travassos, 1927 (Rhabditida: Steinernematidae) and Heterorhabditis Poinar, 1976 (Rhabditida: Heterorhabditidae) nematodes, respectively, and are known to produce several secondary metabolites that protect nematode-killed insects from different competitors. One of these compounds called “the scavenger deterrent factor” (SDF) is known to deter different arthropod, bird, and fish species from feeding on insects killed by Xenorhabdus or Photorhabdus bacteria. The effects of SDF from five different Xenorhabdus and one Photorhabdus species against the Norway rat, Rattus norvegicus (Berkenhout, 1769) (Rodentia: Muridae) were investigated using either a one-choice or two-choice experimental design during 2019-2020 in Aydın Adnan Menderes University. Rats were given four-day-old bacteria-killed Galleria mellonella (L., 1758) (Lepidoptera: Pyralidae) larvae and feeding behavior was observed and recorded. The results demonstrate that the Norway rat is deterred from feeding on insects killed by certain Xenorhabdus and Photorhabdus species and it is likely due to the distastefulness of these cadavers. Ecologically, the data suggest that insects killed by the entomopathogenic nematode/bacterium complex in nature may be protected from attack from insectivorous mammals, especially those that feed on soil-dwelling insects.

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Li, Jianxiong, Genhui Chen und John M. Webster. „Nematophin, a novel antimicrobial substance produced byXenorhabdus nematophilus(Enterobactereaceae)“. Canadian Journal of Microbiology 43, Nr. 8 (01.08.1997): 770–73. http://dx.doi.org/10.1139/m97-110.

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A new antibiotic, nematophin, was isolated from strain BC1 of Xenorhabdus nematophilus and detected in all strains of X. nematophilus studied. Its structure is fully established as 3-indoleethyl (3′-methyl-2′-oxo)pentanamide by extensive spectroscopic study. The production of nematophin is affected by the strain type and culture conditions. The compound shows strong in vitro bioactivity against a series of fungal and bacterial species.Key words: nematophin, symbiotic bacteria, Xenorhabdus nematophilus, antibiotic.

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Samaliev, Harry, Fotini Andreoglou, Sami Elawad, Nigel Hague und Simon Gowen. „The nematicidal effects of the bacteria Pseudomonas oryzihabitans and Xenorhabdus nematophilus on the root-knot nematode Meloidogyne javanica“. Nematology 2, Nr. 5 (2000): 507–14. http://dx.doi.org/10.1163/156854100509420.

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Abstract In two laboratory experiments and one pot experiment the influence of the bacterial symbionts Pseudomonas oryzihabitans from Steinernema abbasi and Xenorhabdus nematophilus from S. carpocapsae on the root-knot nematode Meloidogyne javanica was investigated. Exposure of egg masses of M. javanica to the bacteria and their metabolites resulted in reduced hatching of second stage juveniles (J2). J2 in contact with the bacteria and their metabolites exhibited disorientation and convulsive movements, but when they were washed and placed in fresh water, many regained normal movement. At dosages of 106 and 107 cells ml-1 mortality was 100% after 24 h exposure, Xenorhabdus being more toxic than Pseudomonas. In soil X. nematophilus was ineffective but P.oryzihabitans prevented invasion of J2 into tomato roots and there was evidence that the bacterium or its metabolites interfered with nematode development in galls. Overall, the results indicate that P.oryzihabitans may provide a possible control strategy for root-knot nematodes. Action nématicide des bactéries Pseudomonas oryzihabitans et Xenorhabdus nematophilus sur le nématode Meloidogyne javanica - Les présentes recherches, au travers de deux expériences au laboratoire et d'une troisième en pots, ont concerné l'influence sur le nématode Meloidogyne javanica des symbiontes bactériens Pseudomonas oryzihinabitans, provenant de Steinernema abbasi, et Xenorhabdus nematophilus, de S. carpocapsae. L'exposition de masses d'œufs de M. javanica aux bactéries et à leurs métabolites a provoqué une diminution de l'éclosion des juvéniles de deuxième stade (J2). Les J2 en contact avec les bactéries et leurs métabolites se sont montrés désorientés et sujets à des mouvements convulsifs mais, après qu'ils aient été lavés et placés dans une eau pure, bon nombre d'entre eux ont recouvré des mouvements normaux. Aux doses de 106 et 107 cellules/ml-1 la mortalité était de 100% après une exposition de 24 h, Xenorhabdus s'étant révélé plus toxique que Pseudomonas . Dans le sol, Xenorhabdus s'est montré inefficace tandis que Pseudomonas empêchait la pénétration des J2 dans les racines de tomate; de plus, il semblerait évident que les bactéries ou leurs métabolites aient une influence sur le développement des nématodes dans les galles. Dans l'ensemble, les résultats indiquent que P.oryzihinabitans peut fournir une éventuelle stratégie de contrôle envers les Meloidogyne.

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Shaik, Haq Abdul, und Archana Mishra. „Influence of Asafoetida Extract on the Virulence of the Entomopathogenic Nematode Steinernema carpocapsae and Its Symbiotic Bacterium Xenorhabdus nematophila in the Host Pyrrhocoris apterus“. Microorganisms 11, Nr. 7 (28.06.2023): 1678. http://dx.doi.org/10.3390/microorganisms11071678.

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Nematode–microbe symbiosis plays a key role in determining pathogenesis against pests. The modulation of symbiotic bacteria may affect the virulence of entomopathogenic nematodes (EPNs) and the biological management of pests. We tested the influence of asafoetida (ASF) extract on the virulence of Steinernema carpocapsae and its symbiotic bacterium, Xenorhabdus nematophila, in Pyrrhocoris apterus. A total of 100 mg of ASF killed 30% of EPNs in 48 h, while P. apterus remained unaffected. The EPNs pre-treated with 100 mg of ASF influenced P. apterus’s mortality by 24–91.4% during a period of 24 to 72 h. The topical application of ASF acted as a deterrent to S. carpocapsae, lowering host invasion to 70% and delaying infectivity with 30% mortality for 168 h. Interestingly, Steinernema’s symbiotic bacterium, Xenorhabdus, remained unaffected by ASF. An in vitro turbidity test containing 100 mg of ASF in a medium increased the growth rate of Xenorhabdus compared to a control. A disc diffusion assay confirmed the non-susceptibility of Xenorhabdus to ASF compared to a positive control, streptomycin. Pro-phenol oxidase (PPO) and phenol oxidase (PO) upregulation showed that ASF influences immunity, while EPN/ASF showed a combined immunomodulatory effect in P. apterus. We report that ASF modulated the virulence of S. carpocapsae but not that of its symbiotic bacterium, X. nematophila, against P. apterus.

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Wenski, Sebastian L., Harun Cimen, Natalie Berghaus, Sebastian W. Fuchs, Selcuk Hazir und Helge B. Bode. „Fabclavine diversity in Xenorhabdus bacteria“. Beilstein Journal of Organic Chemistry 16 (07.05.2020): 956–65. http://dx.doi.org/10.3762/bjoc.16.84.

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The global threat of multiresistant pathogens has to be answered by the development of novel antibiotics. Established antibiotic applications are often based on so-called secondary or specialized metabolites (SMs), identified in large screening approaches. To continue this successful strategy, new sources for bioactive compounds are required, such as the bacterial genera Xenorhabdus or Photorhabdus. In these strains, fabclavines are widely distributed SMs with a broad-spectrum bioactivity. Fabclavines are hybrid SMs derived from nonribosomal peptide synthetases (NRPS), polyunsaturated fatty acid (PUFA), and polyketide synthases (PKS). Selected Xenorhabdus and Photorhabdus mutant strains were generated applying a chemically inducible promoter in front of the suggested fabclavine (fcl) biosynthesis gene cluster (BGC), followed by the analysis of the occurring fabclavines. Subsequently, known and unknown derivatives were identified and confirmed by MALDI–MS and MALDI–MS2 experiments in combination with an optimized sample preparation. This led to a total number of 22 novel fabclavine derivatives in eight strains, increasing the overall number of fabclavines to 32. Together with the identification of fabclavines as major antibiotics in several entomopathogenic strains, our work lays the foundation for the rapid fabclavine identification and dereplication as the basis for future work of this widespread and bioactive SM class.

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Volgyi, Antonia, Andras Fodor, Attila Szentirmai und Steven Forst. „Phase Variation in Xenorhabdus nematophilus“. Applied and Environmental Microbiology 64, Nr. 4 (01.04.1998): 1188–93. http://dx.doi.org/10.1128/aem.64.4.1188-1193.1998.

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ABSTRACT Xenorhabdus nematophilus is a symbiotic bacterium that inhabits the intestine of entomopathogenic nematodes. The bacterium-nematode symbiotic pair is pathogenic for larval-stage insects. The phase I cell type is the form of the bacterium normally associated with the nematode. A variant cell type, referred to as phase II, can form spontaneously under stationary-phase conditions. Phase II cells do not elaborate products normally associated with the phase I cell type. To better define phase variation in X. nematophilus, several strains (19061, AN6, F1, N2-4) of this bacterium were analyzed for new phenotypic traits. An analysis of pathogenicity in Manduca sexta larvae revealed that the phase II form of AN6 (AN6/II) was significantly less virulent than the phase I form (AN6/I). The variant form of N2-4 was also avirulent. On the other hand, F1/II and 19061/II were as virulent as the respective phase I cells. Strain 19061/II was found to be motile, and AN6/II regained motility when the bacteria were grown in low-osmolarity medium. In contrast, F1/II remained nonmotile. The phase II cells did not produce the outer membrane protein, OpnB, that is normally induced during the stationary phase. Both phase I and phase II cells were able to support nematode growth and development. These findings indicate that while certain phenotypic traits are common to all phase II cells, other characteristics, such as virulence and motility, are variable and can be influenced by environmental conditions.

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Yimthin, Thatcha, Chamaiporn Fukruksa, Paramaporn Muangpat, Abdulhakam Dumidae, Wandee Wattanachaiyingcharoen, Apichat Vitta und Aunchalee Thanwisai. „A study on Xenorhabdus and Photorhabdus isolates from Northeastern Thailand: Identification, antibacterial activity, and association with entomopathogenic nematode hosts“. PLOS ONE 16, Nr. 8 (12.08.2021): e0255943. http://dx.doi.org/10.1371/journal.pone.0255943.

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Xenorhabdus and Photorhabdus are gram negative bacteria that can produce several secondary metabolites, including antimicrobial compounds. They have a symbiotic association with entomopathogenic nematodes (EPNs). The aim of this study was to isolate and identify Xenorhabdus and Photorhabdus species and their associated nematode symbionts from Northeastern region of Thailand. We also evaluated the antibacterial activity of these symbiotic bacteria. The recovery rate of EPNs was 7.82% (113/1445). A total of 62 Xenorhabdus and 51 Photorhabdus strains were isolated from the EPNs. Based on recA sequencing and phylogeny, Xenorhabdus isolates were identified as X. stockiae (n = 60), X. indica (n = 1) and X. eapokensis (n = 1). Photorhabdus isolates were identified as P. luminescens subsp. akhurstii (n = 29), P. luminescens subsp. hainanensis (n = 18), P. luminescens subsp. laumondii (n = 2), and P. asymbiotica subsp. australis (n = 2). The EPNs based on 28S rDNA and internal transcribed spacer (ITS) analysis were identified as Steinernema surkhetense (n = 35), S. sangi (n = 1), unidentified Steinernema (n = 1), Heterorhabditis indica (n = 39), H. baujardi (n = 1), and Heterorhabditis sp. SGmg3 (n = 3). Antibacterial activity showed that X. stockiae (bMSK7.5_TH) extract inhibited several antibiotic-resistant bacterial strains. To the best of our knowledge, this is the first report on mutualistic association between P. luminescens subsp. laumondii and Heterorhabditis sp. SGmg3. This study could act as a platform for future studies focusing on the discovery of novel antimicrobial compounds from these bacterial isolates.

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Brown, S. E., A. T. Cao, P. Dobson, E. R. Hines, R. J. Akhurst und P. D. East. „Txp40, a Ubiquitous Insecticidal Toxin Protein from Xenorhabdus and Photorhabdus Bacteria“. Applied and Environmental Microbiology 72, Nr. 2 (Februar 2006): 1653–62. http://dx.doi.org/10.1128/aem.72.2.1653-1662.2006.

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ABSTRACT Xenorhabdus and Photorhabdus are gram-negative bacteria that produce a range of proteins that are toxic to insects. We recently identified a novel 42-kDa protein from Xenorhabdus nematophila that was lethal to the larvae of insects such as Galleria mellonella and Helicoverpa armigera when it was injected at doses of 30 to 40 ng/g larvae. In the present work, the toxin gene txp40 was identified in another 59 strains of Xenorhabdus and Photorhabdus, indicating that it is both highly conserved and widespread among these bacteria. Recombinant toxin protein was shown to be active against a variety of insect species by direct injection into the larvae of the lepidopteran species G. mellonella, H. armigera, and Plodia interpunctella and the dipteran species Lucilia cuprina. The protein exhibited significant cytotoxicity against two dipteran cell lines and two lepidopteran cell lines but not against a mammalian cell line. Histological data from H. armigera larvae into which the toxin was injected suggested that the primary site of action of the toxin is the midgut, although some damage to the fat body was also observed.

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Sicard, Mathieu, Karine Brugirard-Ricaud, Sylvie PagÃ¯Â¿Â½s, Anne Lanois, Noel E. Boemare, Michel BrehÃ¯Â¿Â½lin und Alain Givaudan. „Stages of Infection during the Tripartite Interaction between Xenorhabdus nematophila, Its Nematode Vector, and Insect Hosts“. Applied and Environmental Microbiology 70, Nr. 11 (November 2004): 6473–80. http://dx.doi.org/10.1128/aem.70.11.6473-6480.2004.

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ABSTRACT Bacteria of the genus Xenorhabdus are mutually associated with entomopathogenic nematodes of the genus Steinernema and are pathogenic to a broad spectrum of insects. The nematodes act as vectors, transmitting the bacteria to insect larvae, which die within a few days of infection. We characterized the early stages of bacterial infection in the insects by constructing a constitutive green fluorescent protein (GFP)-labeled Xenorhabdus nematophila strain. We injected the GFP-labeled bacteria into insects and monitored infection. We found that the bacteria had an extracellular life cycle in the hemolymph and rapidly colonized the anterior midgut region in Spodoptera littoralis larvae. Electron microscopy showed that the bacteria occupied the extracellular matrix of connective tissues within the muscle layers of the Spodoptera midgut. We confirmed the existence of such a specific infection site in the natural route of infection by infesting Spodoptera littoralis larvae with nematodes harboring GFP-labeled Xenorhabdus. When the infective juvenile (IJ) nematodes reached the insect gut, the bacterial cells were rapidly released from the intestinal vesicle into the nematode intestine. Xenorhabdus began to escape from the anus of the nematodes when IJs were wedged in the insect intestinal wall toward the insect hemolymph. Following their release into the insect hemocoel, GFP-labeled bacteria were found only in the anterior midgut region and hemolymph of Spodoptera larvae. Comparative infection assays conducted with another insect, Locusta migratoria, also showed early bacterial colonization of connective tissues. This work shows that the extracellular matrix acts as a particular colonization site for X. nematophila within insects.

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Rivera-Ramírez, Abraham, Rosalba Salgado-Morales, Alfredo Jiménez-Pérez, Rebeca Pérez-Martínez, Blanca Inés García-Gómez und Edgar Dantán-González. „Comparative Genomics and Pathogenicity Analysis of Two Bacterial Symbionts of Entomopathogenic Nematodes: The Role of the GroEL Protein in Virulence“. Microorganisms 10, Nr. 3 (22.02.2022): 486. http://dx.doi.org/10.3390/microorganisms10030486.

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Bacteria of the genera Xenorhabdus and Photorhabdus are symbionts of entomopathogenic nematodes. Despite their close phylogenetic relationship, they show differences in their pathogenicity and virulence mechanisms in target insects. These differences were explored by the analysis of the pangenome, as it provides a framework for characterizing and defining the gene repertoire. We performed the first pangenome analysis of 91 strains of Xenorhabdus and Photorhabdus; the analysis showed that the Photorhabdus genus has a higher number of genes associated with pathogenicity. However, biological tests showed that whole cells of X. nematophila SC 0516 were more virulent than those of P. luminescens HIM3 when both were injected into G. mellonella larvae. In addition, we cloned and expressed the GroEL proteins of both bacteria, as this protein has been previously indicated to show insecticidal activity in the genus Xenorhabdus. Among these proteins, Cpn60-Xn was found to be the most toxic at all concentrations tested, with an LC50 value of 102.34 ng/larva. Sequence analysis suggested that the Cpn60-Xn toxin was homologous to Cpn60-Pl; however, Cpn60-Xn contained thirty-five differentially substituted amino acid residues that could be responsible for its insecticidal activity.

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Goetsch, M., H. Owen, B. Goldman und S. Forst. „Analysis of the PixA Inclusion Body Protein of Xenorhabdus nematophila“. Journal of Bacteriology 188, Nr. 7 (01.04.2006): 2706–10. http://dx.doi.org/10.1128/jb.188.7.2706-2710.2006.

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ABSTRACT The symbiotic pathogenic bacterium Xenorhabdus nematophila produces two distinct intracellular inclusion bodies. The pixA gene, which encodes the 185-residue methionine-rich PixA inclusion body protein, was analyzed in the present study. The pixA gene was optimally expressed under stationary-phase conditions but its expression did not require RpoS. Analysis of a pixA mutant strain showed that PixA was not required for virulence towards the insect host or for colonization of or survival within the nematode host, and was not essential for nematode reproduction. The pixA gene was not present in the genome of Xenorhabdus bovienii, which also produces proteinaceous inclusions, indicating that PixA is specifically produced in X. nematophila.

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Reimer, Daniela, Friederike I. Nollmann, Katharina Schultz, Marcel Kaiser und Helge B. Bode. „Xenortide Biosynthesis by Entomopathogenic Xenorhabdus nematophila“. Journal of Natural Products 77, Nr. 8 (31.07.2014): 1976–80. http://dx.doi.org/10.1021/np500390b.

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Proschak, Anna, Katharina Schultz, Jennifer Herrmann, Andrea J. Dowling, Alexander O. Brachmann, Richard ffrench-Constant, Rolf Müller und Helge B. Bode. „Cytotoxic Fatty Acid Amides from Xenorhabdus“. ChemBioChem 12, Nr. 13 (12.07.2011): 2011–15. http://dx.doi.org/10.1002/cbic.201100223.

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Tailliez, Patrick, Christine Laroui, Nadège Ginibre, Armelle Paule, Sylvie Pagès und Noël Boemare. „Phylogeny of Photorhabdus and Xenorhabdus based on universally conserved protein-coding sequences and implications for the taxonomy of these two genera. Proposal of new taxa: X. vietnamensis sp. nov., P. luminescens subsp. caribbeanensis subsp. nov., P. luminescens subsp. hainanensis subsp. nov., P. temperata subsp. khanii subsp. nov., P. temperata subsp. tasmaniensis subsp. nov., and the reclassification of P. luminescens subsp. thracensis as P. temperata subsp. thracensis comb. nov.“ International Journal of Systematic and Evolutionary Microbiology 60, Nr. 8 (01.08.2010): 1921–37. http://dx.doi.org/10.1099/ijs.0.014308-0.

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We used the information from a set of concatenated sequences from four genes (recA, gyrB, dnaN and gltX) to investigate the phylogeny of the genera Photorhabdus and Xenorhabdus (entomopathogenic bacteria associated with nematodes of the genera Heterorhabditis and Steinernema, respectively). The robustness of the phylogenetic tree obtained by this multigene approach was significantly better than that of the tree obtained by a single gene approach. The comparison of the topologies of single gene phylogenetic trees highlighted discrepancies which have implications for the classification of strains and new isolates; in particular, we propose the transfer of Photorhabdus luminescens subsp. thracensis to Photorhabdus temperata subsp. thracensis comb. nov. (type strain CIP 108426T =DSM 15199T). We found that, within the genus Xenorhabdus, strains or isolates that shared less than 97 % nucleotide identity (NI), calculated on the concatenated sequences of the four gene fragments (recA, gyrB, dnaN and gltX) encompassing 3395 nucleotides, did not belong to the same species. Thus, at the 97 % NI cutoff, we confirm the current 20 species of the genus Xenorhabdus and propose the description of a novel species, Xenorhabdus vietnamensis sp. nov. (type strain VN01T = CIP 109945T =DSM 22392T). Within each of the three current species of the genus Photorhabdus, P. asymbiotica, P. luminescens and P. temperata, strains or isolates which shared less than 97 % NI did not belong to the same subspecies. Comparisons of the four gene fragments plus the rplB gene fragment analysed separately led us to propose four novel subspecies: Photorhabdus luminescens subsp. caribbeanensis subsp. nov. (type strain HG29T =CIP 109949T =DSM 22391T), P. luminescens subsp. hainanensis subsp. nov. (type strain C8404T = CIP 109946T =DSM 22397T), P. temperata subsp. khanii subsp. nov. (type strain C1T =NC19T =CIP 109947T =DSM 3369T), and P. temperata subsp. tasmaniensis subsp. nov. (type strain T327T = CIP 109948T =DSM 22387T).

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Massaoud, Mustafa K., Judit MarokhÃ¯Â¿Â½zi, AndrÃ¯Â¿Â½s Fodor und IstvÃ¯Â¿Â½n Venekei. „Proteolytic Enzyme Production by Strains of the Insect Pathogen Xenorhabdus and Characterization of an Early-Log-Phase-Secreted Protease as a Potential Virulence Factor“. Applied and Environmental Microbiology 76, Nr. 20 (27.08.2010): 6901–9. http://dx.doi.org/10.1128/aem.01567-10.

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ABSTRACT As a comparison to a similar study on Photorhabdus strains, 15 Xenorhabdus bacterial strains and secondary phenotypic variants of two strains were screened for proteolytic activity by five detection methods. Although the number and intensity of proteolytic activities were different, every strain was positive for proteolytic activity by several tests. Zymography following native PAGE detected two groups of activities with different substrate affinities and a higher and lower electrophoretic mobility that were distinguished as activity 1 and 2, respectively. Zymography following SDS-PAGE resolved three activities, which were provisionally named proteases A, B, and C. Only protease B, an ∼55-kDa enzyme, was produced by every strain. This enzyme exhibited higher affinity to the gelatin substrate than to the casein substrate. Of the chromogenic substrates used, three were hydrolyzed: furylacryloyl-Ala-Leu-Val-Tyr (Fua-ALVY), Fua-LGPA (LGPA is Leu-Gly-Pro-Ala) (a substrate for collagen peptidases), and succinyl-Ala-Ala-Pro-Phe-thiobenzyl (Succ-AAPF-SBzl). All but the Fua-LGPA-ase activity seemed to be from secreted enzymes. According to their substrate preference profiles and inhibitor sensitivities, at least six such proteolytic enzymes could be distinguished in the culture medium of Xenorhabdus strains. The proteolytic enzyme that was secreted the earliest, protease B and the Succ-AAPF-SBzl-hydrolyzing enzyme, appeared from the early logarithmic phase of growth. Protease B could also be detected in the hemolymph of Xenorhabdus-infected Galleria mellonella larvae from 15 h postinfection. The purified protease B hydrolyzed in vitro seven proteins in the hemolymph of Manduca sexta that were also cleaved by PrtA peptidase from Photorhabdus. The N-terminal sequence of protease B showed similarity to a 55-kDa serralysin type metalloprotease in Xenorhabdus nematophila, which had been identified as an orthologue of Photorhabdus PrtA peptidase.

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Skowronek, Marcin, Ewa Sajnaga, Waldemar Kazimierczak, Magdalena Lis und Adrian Wiater. „Screening and Molecular Identification of Bacteria from the Midgut of Amphimallon solstitiale Larvae Exhibiting Antagonistic Activity against Bacterial Symbionts of Entomopathogenic Nematodes“. International Journal of Molecular Sciences 22, Nr. 21 (05.11.2021): 12005. http://dx.doi.org/10.3390/ijms222112005.

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Entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) are a group of organisms capable of infecting larvae of insects living in soil, including representatives of the family Scarabaeidae. Their insecticidal activity is related to the presence of symbiotic bacteria Xenorhabdus spp. or Photorhabdus spp. in the alimentary tract, which are released into the insect body, leading to its death caused by bacterial toxins and septicemia. Although the antibacterial activities of symbionts of entomopathogenic nematodes have been well described, there is insufficient knowledge of the interactions between these bacteria and microorganisms that naturally inhabit the alimentary tract of insects infested by nematodes. In this study, 900 bacterial strains isolated from midgut samples of Amphimallon solstitiale larvae were tested for their antagonistic activity against the selected five Xenorhabdus and Photorhabdus species. Cross-streak tests showed significant antibacterial activity of 20 isolates. These bacteria were identified as Bacillus [Brevibacterium] frigoritolerans, Bacillus toyonensis, Bacillus wiedmannii, Chryseobacterium lathyri, Chryseobacterium sp., Citrobacter murliniae, Enterococcus malodoratus, Paenibacillus sp., Serratia marcescens and Serratia sp. Since some representatives of the intestinal microbiota of A. solstitiale are able to inhibit the growth of Xenorhabdus and Photorhrhabdus bacteria in vitro, it can be assumed that this type of bacterial interaction may occur at certain stages of insect infection by Steinernema or Heterorhabditis nematodes.

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Snyder, Holly, S. Patricia Stock, Sam-Kyu Kim, Yolanda Flores-Lara und Steven Forst. „New Insights into the Colonization and Release Processes of Xenorhabdus nematophila and the Morphology and Ultrastructure of the Bacterial Receptacle of Its Nematode Host, Steinernema carpocapsae“. Applied and Environmental Microbiology 73, Nr. 16 (25.05.2007): 5338–46. http://dx.doi.org/10.1128/aem.02947-06.

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ABSTRACT We present results from epifluorescence, differential interference contrast, and transmission electron microscopy showing that Xenorhabdus nematophila colonizes a receptacle in the anterior intestine of the infective juvenile (IJ) stage of Steinernema carpocapsae. This region is connected to the esophagus at the esophagointestinal junction. The process by which X. nematophila leaves this bacterial receptacle had not been analyzed previously. In this study we monitored the movement of green fluorescent protein-labeled bacteria during the release process. Our observations revealed that Xenorhabdus colonizes the distal region of the receptacle and that exposure to insect hemolymph stimulated forward movement of the bacteria to the esophagointestinal junction. Continued exposure to hemolymph caused a narrow passage in the distal receptacle to widen, allowing movement of Xenorhabdus down the intestine and out the anus. Efficient release of both the wild type and a nonmotile strain was evident in most of the IJs incubated in hemolymph, whereas only a few IJs incubated in nutrient-rich broth released bacterial cells. Incubation of IJs in hemolymph treated with agents that induce nematode paralysis dramatically inhibited the release process. These results suggest that bacterial motility is not required for movement out of the distal region of the receptacle and that hemolymph-induced esophageal pumping provides a force for the release of X. nematophila out of the receptacle and into the intestinal lumen.

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He, Hongjun, Holly A. Snyder und Steven Forst. „Unique organization and regulation of the mrx fimbrial operon in Xenorhabdus nematophila“. Microbiology 150, Nr. 5 (01.05.2004): 1439–46. http://dx.doi.org/10.1099/mic.0.26853-0.

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Xenorhabdus nematophila, a Gram-negative bacterium belonging to the Proteus clade of the family Enterobacteriaceae, forms a mutualistic association with the soil nematode Steinernema carpocapsae. The nematode invades insects and releases Xenorhabdus into the haemolymph, where it participates in insect killing. To begin to understand the role of fimbriae in the unique life cycle of Xenorhabdus, the organization and expression of the mrx fimbrial operon was analysed. The mrx operon contained only five structural genes (mrxACDGH), making it one of the smallest chaperone-usher fimbrial operons studied to date. Unlike the mrp operon of Proteus mirabilis, a site-specific recombinase was not linked to the mrx operon. The intergenic region between the major fimbrial gene (mrxA) and the usher gene (mrxC) lacked a mrpB-like gene, but contained three tandem inverted repeat sequences located downstream of mrxA. A 940 nt mrxA-containing mRNA was the major transcript produced in cells growing on agar, while an mrx polycistronic mRNA was produced at low levels. A canonical σ 70 promoter, identified upstream of mrxA, was not subject to promoter inversion. Fimbriae were not produced in an lrp-mutant strain, suggesting that the leucine-responsive regulatory protein, Lrp, plays a role in the regulation of the mrx operon. These findings show that the genetic organization and regulation of the mrx operon is in several respects distinct from other chaperone-usher fimbrial operons.

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Schmidt, T. M., K. Kopecky und K. H. Nealson. „Bioluminescence of the insect pathogen Xenorhabdus luminescens.“ Applied and Environmental Microbiology 55, Nr. 10 (1989): 2607–12. http://dx.doi.org/10.1128/aem.55.10.2607-2612.1989.

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Hurlbert, Ronald E., Jimin Xu und Christopher L. Small. „Colonial and Cellular Polymorphism in Xenorhabdus luminescens“. Applied and Environmental Microbiology 55, Nr. 5 (1989): 1136–43. http://dx.doi.org/10.1128/aem.55.5.1136-1143.1989.

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Xu, Jimin, und Ronald E. Hurlbert. „Toxicity of Irradiated Media for Xenorhabdus spp“. Applied and Environmental Microbiology 56, Nr. 3 (1990): 815–18. http://dx.doi.org/10.1128/aem.56.3.815-818.1990.

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Leclerc, M. C., und N. E. Boemare. „Plasmids and phase variation in Xenorhabdus spp.“ Applied and Environmental Microbiology 57, Nr. 9 (1991): 2597–601. http://dx.doi.org/10.1128/aem.57.9.2597-2601.1991.

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