Project description:This research investigates the molecular mechanisms of trait deterioration of two experimental lines of entamopathogenic nematodes, an inbred line (L5M) and its original parental line (OHB), created by sub-culturing different experimental lines of the nematode-bacterium complex over 20 passages in insect hosts. These lines differed in their virulence, heat tolerance and fecundity . Transcriptional profiles of the two experimental lines were determined and select differentially expressed genes were validated by quantitative PCR. Samples from four biological replicates each of the parental strain (OHB) and the laboratory strain (L5M) were hybridized to the custom H. bacteriophora arrays.
Project description:This research investigates the molecular mechanisms of trait deterioration of two experimental lines of entamopathogenic nematodes, an inbred line (L5M) and its original parental line (OHB), created by sub-culturing different experimental lines of the nematode-bacterium complex over 20 passages in insect hosts. These lines differed in their virulence, heat tolerance and fecundity . Transcriptional profiles of the two experimental lines were determined and select differentially expressed genes were validated by quantitative PCR.
Project description:We report the application of next generation RNA sequencing to analyze the transcriptional response of Drosophila adult flies to infection by the insect pathogenic nematodes Heterorhabditis bacteriophora and their mutualistic bacteria Photorhabdus luminescens, either separately or together. We find that Heterorhabditis and Photorhabdus differentially modulate a large number of genes, many of which participate in metabolic functions, stress responses, repression of gene transcription and neuronal activities. We have also identified Drosophila genes with potential role in nematode recognition and others with putative anti-nematode properties. These findings generate novel insights into how the host immune function is shaped to respond against nematode parasites and their associated bacteria. Transcriptional profiles of Drosophila wild-type adult flies infected with Heterorhabditis bacteriophora carrying or lacking Photorhabdus or the bacteria alone were generated at 12 and 30 hours post infection using Illumina deep sequencing technology.
Project description:We report the application of next generation RNA sequencing to analyze the transcriptional response of Drosophila adult flies to infection by the insect pathogenic nematodes Heterorhabditis bacteriophora and their mutualistic bacteria Photorhabdus luminescens, either separately or together. We find that Heterorhabditis and Photorhabdus differentially modulate a large number of genes, many of which participate in metabolic functions, stress responses, repression of gene transcription and neuronal activities. We have also identified Drosophila genes with potential role in nematode recognition and others with putative anti-nematode properties. These findings generate novel insights into how the host immune function is shaped to respond against nematode parasites and their associated bacteria.
Project description:Entomopathogenic nematodes (EPNs) are gaining significant popularity as biocontrol agents due to their ability to rapidly kill insect hosts. These nematodes produce bioactive molecules known as excreted/secreted products (ESPs) that help them overcome host immune defenses. Understanding the mechanisms that trigger ESP release and their composition is crucial for unraveling the factors underlying nematode pathogenicity and enhancing their effectiveness as biocontrol agents. Leveraging the insect parasitic nematode, Heterorhabditis bacteriophora, we describe an in vitro study focused on the recovery process of infective juveniles upon contact with selected activation materials. We evaluated three host-derived materials from Galleria mellonella larvae: live larvae, frozen larvae, and heat-inactivated homogenates; and two non-insect-derived materials: filtered water and phosphate-buffered saline. While none of the tested materials resulted in 100% IJ recovery, all induced ESP release. The ESPs were collected and analyzed using liquid chromatography-tandem mass spectrometry, resulting in the identification of 372 proteins. The highest number of proteins, approximately 200, were detected in response to heat-inactivated homogenate and phosphate-buffered saline treatment. Among the identified ESPs were proteins involved in immunomodulation and protease inhibition, both crucial for overcoming host defenses. Our findings highlight the complexity of nematode-host interactions and suggest avenues for improving biocontrol strategies through a deeper understanding of nematode activation and the released spectrum of ESPs.
