scholarly journals Bioactive Excreted/Secreted Products of Entomopathogenic Nematode Heterorhabditis bacteriophora Inhibit the Phenoloxidase Activity during the Infection

Insects ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 353 ◽  
Author(s):  
Sara Eliáš ◽  
Jana Hurychová ◽  
Duarte Toubarro ◽  
Jorge Frias ◽  
Martin Kunc ◽  
...  
Keyword(s):  
Immune Response ◽  
Galleria Mellonella ◽  
De Novo ◽  
Entomopathogenic Nematode ◽  
Heterorhabditis Bacteriophora ◽  
Bioactive Molecules ◽  
Phenoloxidase Activity ◽  
Mutualistic Relationship ◽  
Insect Immune Response ◽  
Main Candidate

Entomopathogenic nematodes (EPNs) are efficient insect parasites, that are known for their mutualistic relationship with entomopathogenic bacteria and their use in biocontrol. EPNs produce bioactive molecules referred to as excreted/secreted products (ESPs), which have come to the forefront in recent years because of their role in the process of host invasion and the modulation of its immune response. In the present study, we confirmed the production of ESPs in the EPN Heterorhabditis bacteriophora, and investigated their role in the modulation of the phenoloxidase cascade, one of the key components of the insect immune system. ESPs were isolated from 14- and 21-day-old infective juveniles of H. bacteriophora, which were found to be more virulent than newly emerged nematodes, as was confirmed by mortality assays using Galleria mellonella larvae. The isolated ESPs were further purified and screened for the phenoloxidase-inhibiting activity. In these products, a 38 kDa fraction of peptides was identified as the main candidate source of phenoloxidase-inhibiting compounds. This fraction was further analyzed by mass spectrometry and the de novo sequencing approach. Six peptide sequences were identified in this active ESP fraction, including proteins involved in ubiquitination and the regulation of a Toll pathway, for which a role in the regulation of insect immune response has been proposed in previous studies.

Bacterial feeding nematodes ingest haemocytes in the haemocoel of the insect Galleria mellonella

Parasitology ◽  
2019 ◽  
Vol 147 (3) ◽  
pp. 279-286
Author(s):  
Masaya Ono ◽  
Yoichi Hayakawa ◽  
Toyoshi Yoshiga
Keyword(s):  
Immune Response ◽  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Parasitic Nematodes ◽  
C Elegans ◽  
Greater Wax Moth ◽  
Insect Haemocytes ◽  
Nematode Parasitism ◽  
Insect Immune Response

AbstractInsect parasitic nematodes have acquired mechanisms to evade their host immune response for successful parasitism. Despite the importance of understanding of the evolution of evasion mechanisms from host immunity, insect immune response against non-parasitic nematodes has not been well studied. In our previous study, we demonstrated that a non-insect parasitic nematode Caenorhabditis elegans was not encapsulated by haemocytes in the larvae of the greater wax moth Galleria mellonella. To understand how nematodes influence insect haemocytes to escape encapsulation, we examined the effect of C. elegans on haemocytes in the haemocoel of G. mellonella larvae. Injection of nematodes resulted in the decrease of haemocyte density while mortality and spreading ability of haemocytes, the haematopoietic organs were not affected. In vitro co-incubation of haemocytes with nematodes resulted in a decrease of haemocyte density and we observed feeding on haemocytes by nematodes. Injection of C. elegans feeding-delay mutants into insects did not cause the decrease of haemocyte density. The decrease of haemocyte density was due to the nematode's ingestion of haemocytes. Furthermore, an entomopathogenic nematode and other bacterial feeding nematodes also showed similar feeding behaviour. The nematode's ability to feed on haemocytes may have played an important role in the evolution of nematode parasitism in bacterial-feeding nematodes.

scholarly journals Assessing the Pathogenicity of Two Bacteria Isolated from the Entomopathogenic Nematode Heterorhabditis indica against Galleria mellonella and Some Pest Insects

Insects ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 83
Author(s):  
Rosalba Salgado-Morales ◽  
Fernando Martínez-Ocampo ◽  
Verónica Obregón-Barboza ◽  
Kathia Vilchis-Martínez ◽  
Alfredo Jiménez-Pérez ◽  
...  
Keyword(s):  
16S Rrna ◽  
Galleria Mellonella ◽  
De Novo ◽  
Entomopathogenic Nematode ◽  
23S Rrna ◽  
Its2 Region ◽  
Rrna Gene ◽  
28S Rrna ◽  
Heterorhabditis Indica ◽  
Insecticide Activity

The entomopathogenic nematodes Heterorhabditis are parasites of insects and are associated with mutualist symbiosis enterobacteria of the genus Photorhabdus; these bacteria are lethal to their host insects. Heterorhabditis indica MOR03 was isolated from sugarcane soil in Morelos state, Mexico. The molecular identification of the nematode was confirmed using sequences of the ITS1-5.8S-ITS2 region and the D2/D3 expansion segment of the 28S rRNA gene. In addition, two bacteria HIM3 and NA04 strains were isolated from the entomopathogenic nematode. The genomes of both bacteria were sequenced and assembled de novo. Phylogenetic analysis was confirmed by concatenated gene sequence datasets as Photorhabdus luminescens HIM3 (16S rRNA, 23S rRNA, dnaN, gyrA, and gyrB genes) and Pseudomonas aeruginosa NA04 (16S rRNA, 23S rRNA and gyrB genes). H. indica MOR03 infects Galleria mellonella, Tenebrio molitor, Heliothis subflexa, and Diatraea magnifactella larvae with LC50 values of 1.4, 23.5, 13.7, and 21.7 IJs/cm2, respectively, at 48 h. These bacteria are pathogenic to various insects and have high injectable insecticide activity at 24 h.

VIRULENCE OF ENTOMOPATHOGENIC NEMATODE–BACTERIA COMPLEXES FOR LARVAE OF NOCTUIDS, A GEOMETRID, AND A PYRALID

1990 ◽  
Vol 122 (2) ◽  
pp. 309-319 ◽  
Author(s):  
O.N. Morris ◽  
V. Converse ◽  
J. Harding
Keyword(s):  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Heterorhabditis Bacteriophora ◽  
Steinernema Feltiae ◽  
Agrotis Ipsilon ◽  
Pseudaletia Unipuncta ◽  
Mamestra Configurata ◽  
Euxoa Ochrogaster ◽  
Cold Hardy ◽  
Highly Virulent

AbstractNine entomopathogenic nematode–bacteria complexes were screened for their virulence against larvae of six noctuids, a geometrid, and a pyralid. Ninety-six-hour LD50’s of steinernematids (and heterorhabditids) ranged from 1 to 3 (1–8) infective juveniles in Galleria mellonella (L.), 1–71 (2) in Peridroma soucia (Hbn.), 1–10 (1–3) in Mamestra configurata (Wlk.), 1–28 (3–7) in Euxoa ochrogaster (Gn.), 19 in Lacanobia radix (Wlk.), 22–60 (4) in Pseudaletia unipuncta (Haw.), 2–95 (111) in Agrotis ipsilon (Hufn.), and 3–28 in Paleacrita vernata (Peck). The nematode, Steinernema feltiae LIC, a cold-hardy strain isolated in Newfoundland, was highly virulent for G. mellonella and M. configurata, but not for P. soucia and E. ochrogaster. The number of nematodes invading larvae and the number produced were greater in G. mellonella than in other insects tested. Nematode–bacteria complexes that showed potential for controlling cutworms included S. feltiae, S. glaseri, S. bibionis, Heterorhabditis bacteriophora, and H. heliothidis.

Source of trait deterioration in entomopathogenic nematodes Heterorhabditis bacteriophora and Steinernema carpocapsae during in vivo culture

Nematology ◽  
2006 ◽  
Vol 8 (3) ◽  
pp. 397-409 ◽  
Author(s):  
Anwar L. Bilgrami ◽  
Randy Gaugler ◽  
David I. Shapiro-Ilan ◽  
Byron J. Adams
Keyword(s):  
Heat Tolerance ◽  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Heterorhabditis Bacteriophora ◽  
Steinernema Carpocapsae ◽  
Reproductive Capacity ◽  
Impaired Performance ◽  
Trait Deterioration ◽  
The Stability

Abstract The stability of traits important for biological control was studied in the entomopathogenic nematode-bacteria complexes Heterorhabditis bacteriophora and Steinernema carpocapsae. Five experimental lines of each species were subcultured for 20 serial passages in Galleria mellonella larvae to assess trait stability. Subculturing impaired performance of both H. bacteriophora and S. carpocapsae. Virulence, heat tolerance and fecundity deteriorated in all H. bacteriophora experimental lines, and four out of five experimental lines deteriorated in host-finding ability. All S. carpocapsae experimental lines deteriorated in heat tolerance and nictation, and four out of five experimental lines declined for reproductive capacity, whereas virulence declined in two experimental lines. Determination of whether trait deterioration was due to changes in nematode, bacteria, or both symbiotic partners was tested by exchanging nematodes or bacteria from control populations with nematodes or bacteria from the most deteriorated experimental lines and assessing trait recovery. The source of deterioration varied according to trait, but only the bacterial partner played a role in trait reductions for every trait and species, whereas the nematode was the main source only for S. carpocapsae nictation. These results emphasise the important role each symbiotic partner plays in the stability and expression of beneficial traits.

Effects of tannin-rich host plants on the infection and establishment of the entomopathogenic nematode Heterorhabditis bacteriophora

2015 ◽  
Vol 128 ◽  
pp. 31-36 ◽  
Author(s):  
Itamar Glazer ◽  
Liora Salame ◽  
Levana Dvash ◽  
Hussein Muklada ◽  
Hassan Azaizeh ◽  
...  
Keyword(s):  
Host Plants ◽  
Entomopathogenic Nematode ◽  
Heterorhabditis Bacteriophora

scholarly journals Thioester-Containing Protein-4 Regulates the Drosophila Immune Signaling and Function against the Pathogen Photorhabdus

2016 ◽  
Vol 9 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Upasana Shokal ◽  
Ioannis Eleftherianos
Keyword(s):  
Immune Response ◽  
Photorhabdus Luminescens ◽  
Human Pathogen ◽  
Loss Of Function ◽  
Phenoloxidase Activity ◽  
Microbial Infections ◽  
Immune Pathways ◽  
And Function ◽  
Important Progress

Despite important progress in identifying the molecules that participate in the immune response of Drosophila melanogaster to microbial infections, the involvement of thioester-containing proteins (TEPs) in the antibacterial immunity of the fly is not fully clarified. Previous studies mostly focused on identifying the function of TEP2, TEP3 and TEP6 molecules in the D. melanogaster immune system. Here, we investigated the role of TEP4 in the regulation and function of D. melanogaster host defense against 2 virulent pathogens from the genus Photorhabdus, i.e. the insect pathogenic bacterium Photorhabdus luminescens and the emerging human pathogen P. asymbiotica. We demonstrate that Tep4 is strongly upregulated in adult flies following the injection of Photorhabdus bacteria. We also show that Tep4 loss-of-function mutants are resistant to P. luminescens but not to P. asymbiotica infection. In addition, we find that inactivation of Tep4 results in the upregulation of the Toll and Imd immune pathways, and the downregulation of the Jak/Stat and Jnk pathways upon Photorhabdus infection. We document that loss of Tep4 promotes melanization and phenoloxidase activity in the mutant flies infected with Photorhabdus. Together, these findings generate novel insights into the immune role of TEP4 as a regulator and effector of the D. melanogaster antibacterial immune response.

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