Comparison of metabolites produced in vitro and in vivo by Photorhabdus luminescens, a bacterial symbiont of the entomopathogenic nematode Heterorhabditis megidis

1998 ◽  
Vol 44 (11) ◽  
pp. 1072-1077 ◽  
Author(s):  
Kaiji Hu ◽  
Jianxiong Li ◽  
Wenjie Wang ◽  
Houming Wu ◽  
Hai Lin ◽  
...  
Keyword(s):  
Entomopathogenic Nematode ◽  
Bacterial Symbiont ◽  
Photorhabdus Luminescens ◽  
Heterorhabditis Megidis

Comparison of metabolites produced in vitro and in vivo by Photorhabdus luminescens, a bacterial symbiont of the entomopathogenic nematode Heterorhabditis megidis

1998 ◽  
Vol 44 (11) ◽  
pp. 1072-1077 ◽  
Author(s):  
Kaiji Hu ◽  
Jianxiong Li ◽  
Wenjie Wang ◽  
Houming Wu ◽  
Hai Lin ◽  
...  
Keyword(s):  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Culture Broth ◽  
Bacterial Symbiont ◽  
Natural Source ◽  
Photorhabdus Luminescens ◽  
Heterorhabditis Megidis ◽  
Organic Extracts

The types of metabolites produced by Photorhabdus luminescens C9 when it is introduced by Heterorhabditis megidis 90 into Galleria mellonella larvae are different from those produced in tryptic soy broth. Only 3,5-dihydroxy-4-isopropylstilbene 1 was identified from the organic extracts of P. luminescens culture broth, but both 3,5-dihydroxy-4-isopropylstilbene 1 and 3,5-dihydroxy-4-ethylstilbene 3 were isolated from the organic extracts of nematode-bacterium infected G. mellonella larvae. In addition to two pigments, both of which had been previously reported from P. luminescens C9 culture broth, three pigments, 1,8-dihydroxy-3-methoxy-9,10-anthraquinone 2, 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone 6, and 1,4-dihydroxy-2,5-dimethoxy-9,10-anthraquinone 7 were isolated from the organic extracts of G. mellonella larvae infected by the nematode-bacterium complex. Among these, compounds 6 and 7 are novel and isolated from a natural source for the first time.Key words: Photorhabdus luminescens, Heterorhabditis megidis, 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone, 1,4-dihydroxy-2,5-dimethoxy-9,10-anthraquinone, pigment.

In vivo production of entomopathogenic nematodes suppressed by asymptomatic bacterial contaminants

Nematology ◽  
2020 ◽  
Vol 22 (8) ◽  
pp. 917-925
Author(s):  
Akanksha Upadhyay ◽  
Sharad Mohan
Keyword(s):  
Biological Control ◽  
Entomopathogenic Nematodes ◽  
Photorhabdus Luminescens ◽  
Ochrobactrum Anthropi ◽  
Progeny Production ◽  
Bacterial Contaminants ◽  
Significant Difference ◽  
Biological Control Of Insects

Summary Entomopathogenic nematodes (EPN) are excellent biological control agents possessing recycling ability as one of their major attributes. We report the presence of asymptomatic bacteria that can lead to disrupted or low progeny production in Heterorhabditis indica. In a one-to-one in vitro competitive bioassay with contaminants associated with H. indica cuticle, there was a significant suppression in the growth of Sphingomonas koreensis when stressed with the nematode symbiont Photorhabdus luminescens; however, P. luminescens was suppressed when sandwiched between Ochrobactrum anthropi. Bacillus bombysepticus associated with laboratory-reared Galleria when stressed by P. luminescens was significantly suppressed, but not so in the reverse assay. Both O. anthropi and B. bombysepticus were found to be insecticidal to Galleria larvae when fed orally. Tripartite interactive studies on the growth and multiplication of H. indica-P. luminescens symbionts in Galleria larvae, predisposed to S. koreensis, revealed no significant difference initially in the hermaphrodite formation, but subsequently there was a significant decline in the formation of amphimictic females and the final production of infective juveniles. In in vitro studies, none of the contaminants supported the growth and development of axenic H. indica. Adequate precautions should be taken to maintain proper hygiene to eliminate such contaminants while culturing the Galleria and EPN for use in the biological control of insects.

scholarly journals YtxR, a Conserved LysR-Like Regulator That Induces Expression of Genes Encoding a Putative ADP-Ribosyltransferase Toxin Homologue in Yersinia enterocolitica

2006 ◽  
Vol 188 (23) ◽  
pp. 8033-8043 ◽  
Author(s):  
Grace L. Axler-DiPerte ◽  
Virginia L. Miller ◽  
Andrew J. Darwin
Keyword(s):  
Yersinia Enterocolitica ◽  
Transcription Initiation ◽  
Photorhabdus Luminescens ◽  
Expression Of Genes ◽  
Dnase I Footprinting ◽  
Genes Encoding ◽  
Adp Ribosyltransferase ◽  
Insight Into

ABSTRACT Yersinia enterocolitica causes human gastroenteritis, and many isolates have been classified as either “American” or “non-American” strains based on their geographic prevalence and virulence properties. In this study we describe identification of a transcriptional regulator that controls expression of the Y. enterocolitica ytxAB genes. The ytxAB genes have the potential to encode an ADP-ribosylating toxin with similarity to pertussis toxin. However, a ytxAB null mutation did not affect virulence in mice. Nevertheless, the ytxAB genes are conserved in many Y. enterocolitica strains. Interestingly, American and non-American strains have different ytxAB alleles encoding proteins that are only 50 to 60% identical. To obtain further insight into the ytxAB locus, we investigated whether it is regulated as part of a known or novel regulon. Transposon mutagenesis identified a LysR-like regulator, which we designated YtxR. Expression of ytxR from a nonnative promoter increased Φ(ytxA-lacZ) operon fusion expression up to 35-fold. YtxR also activated expression of its own promoter. DNase I footprinting showed that a His6-YtxR fusion protein directly interacted with the ytxA and ytxR control regions at similar distances upstream of their probable transcription initiation sites, identified by primer extension. Deletion analysis demonstrated that removal of the regions protected by His6-YtxR in vitro eliminated YtxR-dependent induction in vivo. The ytxAB locus is not present in most Yersinia species. In contrast, ytxR is conserved in multiple Yersinia species, as well as in the closely related organisms Photorhabdus luminescens and Photorhabdus asymbiotica. These observations suggest that YtxR may play a conserved role involving regulation of other genes besides ytxAB.

Influence of temperature on the infectivity of entomopathogenic nematodes (Steinernema and Heterorhabditis spp.) to larvae and pupae of the vine weevil Otiorhynchus sulcatus (Coleoptera: Curculionidae)

Nematology ◽  
2000 ◽  
Vol 2 (3) ◽  
pp. 309-317 ◽  
Author(s):  
Steve Long ◽  
John Fenlon ◽  
Paul Richardson
Keyword(s):  
Competing Risks ◽  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Commercial Product ◽  
Effect Of Temperature ◽  
Heterorhabditis Megidis ◽  
Otiorhynchus Sulcatus ◽  
The Uk

AbstractThe susceptibilities of early and late instar vine weevil larvae and pupae to three species of entomopathogenic nematodes, indigenous to the UK, were tested in a series of bioassays. Steinernema kraussei (isolates L017 and L137), S. feltiae (the commercial product Nemasys®) and Heterorhabditis megidis (the commercial product Nemasys® H, reared both in vivo in Galleria mellonella larvae and in vitro), were tested at 6, 10 and 18°C for 2 weeks (early instars of O. sulcatus) or 3 weeks (late instars and pupae of O. sulcatus). Nematodes were applied to over 3800 larvae or pupae and there were over 400 untreated controls. Each insect was examined subsequently to determine mortality, and parasitised specimens were dissected to establish whether adult nematodes had developed. Differences in pathogenicity between H. megidis reared in vitro and in vivo were demonstrated. S. kraussei (L137) was consistently the most virulent nematode isolate at low temperatures. The results revealed a significant (P < 0.001) effect of temperature on small larvae of O. sulcatus, but also showed differential levels of mortality, not due to nematodes, for both small larvae and pupae. The use of Abbott's correction for control mortality is challenged and the validity of competing risks theory examined.In einer Reihe von Biotests wurde die Anfälligkeit von frühen und späten Larvenstadien sowie Puppen des Rüsselkäfers Otiorhynchus sulcatus gegenüber drei in UK einheimischen entomopathogenen Nematoden untersucht. Steinernema kraussei (isolate L017 und L137), S. feltiae (Handelsprodukt Nemasys®) und Heterorhabditis megidis (Handelsprodukt Nemasys® H, beide in vivo an Larven von Galleria mellonella und in vitro gezüchtet) wurden bei 6, 10 and 18°C für zwei Wochen (frühe Stadien von O. sulcatus) oder drei Wochen (späte Stadien und Puppen von O. sulcatus) geprüft. Über 3800 Larven oder Puppen wurden mit Nematoden behandelt, daneben gab es über 400 unbehandelte Kontrollen. Anschliessend wurde jedes Insekt untersucht, um die Mortalität zu bestimmen. Parasitierte Exemplare wurden aufpräpariert um festzustellen, ob sich adulte Nematoden entwickelt hatten. Zwischen in vitro und in vivo kultivierten H. megidis konnten Unterschiede in der Pathogenität festgestellt werden. S. kraussei (L137) war bei niedrigen Temperaturen durchgehend das virulenteste Isolat. Die Ergebnisse zeigten eine signifikante (P < 0.001) Wirkung der Temperatur auf kleine Larven von O. sulcatus. Sie zeigten für kleine Larven und Puppen aber auch unterschiedliche Mortlitätsgrade an, die nicht auf Nematoden zurückgingen. Die Anwendung von Abbott's Korrektur zur Prüfung der Mortalität wird kritisch hinterfragt, die Gültigkeit der Theorie der “competing risks” wird geprüft.

Effect of inoculum age and physical parameters on in vitro culture of the entomopathogenic nematode Steinernema feltiae

2016 ◽  
Vol 91 (6) ◽  
pp. 686-695 ◽  
Author(s):  
L.G. Leite ◽  
D.I. Shapiro-Ilan ◽  
S. Hazir ◽  
M.A. Jackson
Keyword(s):  
Liquid Medium ◽  
Solid Medium ◽  
Entomopathogenic Nematode ◽  
Steinernema Feltiae ◽  
Physical Parameters ◽  
Symbiotic Association ◽  
Liquid Cultures ◽  
Inoculum Age

AbstractEntomopathogenic nematodes (EPNs) of the families Steinernematidae and Heterorhabditidae have a symbiotic association with bacteria which makes them virulent against insects. EPNs have been mass produced using in vivo and in vitro methods, including both solid and liquid fermentation. This study assessed the effect of nematode inoculum age on the production of Steinernema feltiae in liquid, solid and biphasic processes. Several physical parameters were also assessed: the effect of medium viscosity, flask size and aeration speed on the recovery and yield of infective juveniles (IJs). Inoculum age treatments included inoculum liquid cultures that were 7, 14, 21 and 28 days old. Nematodes from the same inoculum were added to one liquid medium (liquid culture), one solid medium with bacteria previously grown in sponge (solid culture) and a variation of the solid medium (a biphasic culture), in which the bacteria were first grown in liquid and, then, soaked into the sponges, with the purpose of providing a more homogeneous bacterial culture before nematode inoculation. Experiments were conducted in Erlenmeyer flasks. Eight treatments were established involving combinations of three variables: two media (with and without 0.2% agar), two flask sizes (250 and 150 ml) and two agitation speeds (180 and 280 rpm). The study showed increases in nematode yield for liquid cultures, but not for solid or biphasic cultures, with the advance of the inoculum age up to 28 days of growth. Furthermore, the addition of 0.2% agar to the liquid medium and increasing the aeration rate by using larger flasks with higher agitation speed may increase nematode recovery and final yield. The experiments were conducted using shake flasks but the results may also be applicable for bioreactors.

scholarly journals In Vitro and In Vivo Characterization of a Small-Colony Variant of the Primary Form of Photorhabdus luminescensMD (Enterobacteriaceae)

1998 ◽  
Vol 64 (9) ◽  
pp. 3214-3219 ◽  
Author(s):  
Kaiji Hu ◽  
John M. Webster
Keyword(s):  
Galleria Mellonella ◽  
Photorhabdus Luminescens ◽  
Small Colony Variant ◽  
Small Colony ◽  
High Level ◽  
In Vivo Characterization ◽  
Primary Form

ABSTRACT A small-colony variant (Vsm) of the primary form (Vp) ofPhotorhabdus luminescens MD from in vitro and in vivo cultures is described. Unlike the primary form, Vp, the Vsm variant is not the preferred diet of its nematode symbiont, aHeterorhabditis sp., does not support development and reproduction of the nematode, and is less pathogenic than Vp toGalleria mellonella larvae. Vsm cells were carried by 25% of infective juveniles, but they comprised a very low percentage (∼0.4%) of the total cells carried by the juvenile. In vitro subculture and in vivo injection into the larvae with either Vp or Vsm always produced a mixture of both Vp and Vsm. In nematode-bacterium-infected G. mellonella larvae, the Vp population in the hemocoel was high (4 × 109 to 5 × 109 CFU/g of wet insect tissue) at 24 h after infection, decreased about 10-fold by 48 h, and then regained a high level at day 5 before decreasing at day 7 and then remaining relatively constant through day 15 postinfection. The Vsm population, under the same conditions as those of Vp, increased gradually to a high level (9 × 108 CFU/g of wet insect tissue) at day 5 postinfection and then declined gradually through day 15.

Nematicidal metabolites produced by Photorhabdus luminescens (Enterobacteriaceae), bacterial symbiont of entomopathogenic nematodes

Nematology ◽  
1999 ◽  
Vol 1 (5) ◽  
pp. 457-469 ◽  
Author(s):  
Kaiji Hu ◽  
Jianxiong Li ◽  
John M. Webster
Keyword(s):  
Caenorhabditis Elegans ◽  
Secondary Metabolites ◽  
Meloidogyne Incognita ◽  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Nematode Species ◽  
Bacterial Symbiont ◽  
Photorhabdus Luminescens ◽  
Egg Hatch ◽  
Heterorhabditis Megidis

Abstract The secondary metabolites, 3,5-dihydroxy-4-isopropylstilbene (ST) and indole, from the culture filtrate of Photorhabdus luminescens MD, were shown to have nematicidal properties. ST caused nearly 100% mortality of J4 and adults of Aphelenchoides rhytium , Bursaphelenchus spp. and Caenorhabditis elegans at 100 mu g/ml, but had no effect on J2 of Meloidogyne incognita or infective juveniles (IJ) of Heterorhabditis megidis at 200 mu g/ml. Indole was lethal to several nematode species at 300 mu g/ml, and caused a high percentage of Bursaphelenchus spp. (J4 and adults), M. incognita (J2) and Heterorhabditis spp. (IJ) to be paralysed at 300, 100 and 400 mu g/ml, respectively. Both ST and indole inhibited egg hatch of M. incognita . ST repelled IJ of some Steinernema spp. but not IJ of Heterorhabditis spp., and indole repelled IJ of some species of both Steinernema and Heterorhabditis . ST, but not indole, was produced in nematode-infected larval Galleria mellonella after 24 h infection. Von Photorhabdus luminescens (Enterobacteriaceae), einem Symbionten entomopathogener Nematoden gebildete nematizide Metaboliten - Es wurde gezeigt, dass die Sekundarmetaboliten 3,5-Dihydroxy-4-isopropylstilben (ST) und Indol aus dem Kulturfiltrat von Photorhabdus luminescens MD nematizide Eigenschaften besassen. In einer Konzentration von 100 mu g/ml verursachte ST eine fast 100%ige Sterblichkeit bei J4 und Adulten von Aphelenchoides rhytium , Bursaphelenchus spp. und Caenorhabditis elegans , hatte aber bei 200 mu g/ml keine Wirkung auf J2 von Meloidogyne incognita oder auf Infektionsjuvenile (IJ) von Heterorhabditis megidis . Bei 300 mu g/ml war Indol fur etliche Nematodenarten todlich und fuhrte dazu, dass Bursaphelenchus spp. (J4 and Adulte) bei 300, M. incognita (J2) bei 100, und Heterorhabditis spp. (IJ) bei 400 mu g/ml zu einem grossen Teil gelahmt wurden. ST und Indol behinderten beide das Schlupfen von M. incognita . ST wirkte abstossend auf IJ einiger Steinernema -Arten aber nicht auf IJ von Heterorhabditis spp., und Indol wirkte abstossend auf IJ einiger Arten der beiden Gattungen Steinernema und Heterorhabditis . ST wurde in nematoden-befallenen Larven von Galleria mellonella 24 h nach der Infektion gebildet, Indol dagegen nicht.

scholarly journals Monitoring Bioluminescent Staphylococcus aureusInfections in Living Mice Using a Novel luxABCDEConstruct

2000 ◽  
Vol 68 (6) ◽  
pp. 3594-3600 ◽  
Author(s):  
Kevin P. Francis ◽  
Danny Joh ◽  
Carolyn Bellinger-Kawahara ◽  
Matthew J. Hawkinson ◽  
Tony F. Purchio ◽  
...  
Keyword(s):  
Direct Detection ◽  
Promoter Sequence ◽  
Light Signal ◽  
Gram Negative Bacteria ◽  
Photorhabdus Luminescens ◽  
Thigh Muscles ◽  
Dividing Cells ◽  
First Time

ABSTRACT Strains of Staphylococcus aureus were transformed with plasmid DNA containing a Photorhabdus luminescens luxoperon (luxABCDE) that was genetically modified to be functional in both gram-positive and gram-negative bacteria. S. aureus cells containing this novel lux construct, downstream of an appropriate promoter sequence, are highly bioluminescent, allowing the detection of fewer than 100 CFU in vitro (direct detection of exponentially dividing cells in liquid culture). Furthermore, these bacteria produce light stably at 37°C and do not require exogenous aldehyde substrate, thus allowing S. aureus infections in living animals to be monitored by bioluminescence. Two strains of S. aureus 8325-4 that produce high levels of constitutive bioluminescence were injected into the thigh muscles of mice, and the animals were then either treated with the antibiotic amoxicillin or left untreated. Bioluminescence from bacteria present in the thighs of the mice was monitored in vivo over a period of 24 h. The effectiveness of the antibiotic in the treated animals could be measured by a decrease in the light signal. At 8 h, the infection in both groups of treated animals had begun to clear, as judged by a decrease in bioluminescence, and by 24 h no light signal could be detected. In contrast, both groups of untreated mice had strong bioluminescent signals at 24 h. Quantification of CFU from bacteria extracted from the thigh muscles of the mice correlated well with the bioluminescence data. This paper shows for the first time that bioluminescence offers a method for monitoring S. aureus infections in vivo that is sensitive and noninvasive and requires fewer animals than conventional methodologies.

Sign in / Sign up

Export Citation Format

Share Document