Project description:Photorhabdus luminescens bacteria alternate lifestyles between its pathogenic insect host and its mutualistic nematode host. We found that Photorhabdus changes radically from the insect pathogenic form (P-form) to slow growing small cells when initiating mutualism (M-form). Here we characterize the gene expression of the M-form relative to the P-form.
2011-09-15 | GSE32088 | GEO
Project description:Five New Genomes of Indian Photorhabdus Isolates
Project description:Photorhabdus luminescens lives in a mutualistic association with entomopathogenic nematodes and is pathogenic for insects. Variants of Photorhabdus frequently arise. VAR* is a colonial and phenotypic variant displaying delayed pathogenicity in the insect, Spodoptera littoralis. In this study, we evaluated the role of transcriptomic modulation in determining the phenotypic variation and delayed pathogenicity of VAR* with respect to the corresponding wild-type form, TT01alpha. A P. luminescens microarray was used to determine changes in transcript profiles in the exponential and stationary phase growth phase of VAR* and TT01alpha grown in LB broth.
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:Photorhabdus luminescens bacteria alternate lifestyles between its pathogenic insect host and its mutualistic nematode host. We found that Photorhabdus changes radically from the insect pathogenic form (P-form) to slow growing small cells when initiating mutualism (M-form). Here we characterize the gene expression of the M-form relative to the P-form. RNA was extracted from mid-exponential phase bacterial cultures of genetically locked P-form and M-form cells in LB media supplemented with 1 g/liter sodium pyruvate at 28 degree celcius. M-form gene expression was calculated relative to P-form. Three replicates were performed for each biological sample.
Project description:Transcritome study of C.elegans exposed to multiple, different bacterial pathogens. Experiments were performed in set-replicates of either 3 or 5.<br> There are 3 for samples: Aeromonas hydrophila, Enterococcus faecalis, Erwinia carotovora and Photorhabdus luminescens. <br> There are 5 for samples: Serratia marcesens and Escherichia coli (control).<br>
Project description:Photorhabdus luminescens lives in a mutualistic association with entomopathogenic nematodes and is pathogenic for insects. Variants of Photorhabdus frequently arise. VAR* is a colonial and phenotypic variant displaying delayed pathogenicity in the insect, Spodoptera littoralis. In this study, we evaluated the role of transcriptomic modulation in determining the phenotypic variation and delayed pathogenicity of VAR* with respect to the corresponding wild-type form, TT01alpha. A P. luminescens microarray was used to determine changes in transcript profiles in the exponential and stationary phase growth phase of VAR* and TT01alpha grown in LB broth. Direct transcriptomic comparisons were carried out between VAR* and TT01alpha grown in LB broth. RNA were extracted from bacterial cells in the exponential growth phase (6-hour-old culture, 5 x 107 cfu/ml) and stationary phase (45-hour-old culture, 5 x 108 cfu/ml). Each microarray comparison (TT01alpha versus VAR* growth in exponential growth or stationary phase) included six slides, with three dye-swapping replicates. Each microarray comparison is done twice with two independant biological extractions (repbiol1 or 2).
Project description:Secretion systems are used as weapons by a variety of Gram-negative bacteria. Among them the Type VI Secretion System (T6SS) gained more interest throughout the last years. The system functions as a molecular nano-weapon: it is used in inter-kingdom competition by various bacteria to deliver toxic effectors in target cells. Here we describe the role of the T6SS in Photorhabdus laumondii subsp. laumondii strain DJC, an entomopathogenic biocontrol agent able to live in different environmental niches, such as in symbiosis with nematodes and in the rhizosphere on plant roots. Using bioinformatic and protein motif analyses we identified four T6SS gene clusters (T6SS-1, T6SS-2, T6SS-3 and T6SS-4) and multiple orphan T6SS related genes in the genome of P. laumondii. Furthermore, we highlighted 11 T6SS effector-immunity pairs, including three undescribed membrane disrupting effectors, each with putatively different antibacterial activities. By label-free mass spectrometry of P. laumondii wild type cells and respective T6SS-deficient strains, we could point out a cross-link between T6SS and other Photorhabdus’ virulence related mechanisms such as PVCs, T3SS and pyocins. Furthermore, a change in motility as well as in the secondary metabolism was observed upon T6SS-deficiency. Here, we shed light on the T6SS in P. laumondii DJC and suggesting a cross-link of various virulence mechanisms, which could help to gain knowledge on T6SS and better figure out the Photorhabdus ability to live in polymicrobial environments.
