Project description:Transcriptional profiling of C. elegans young adult worms cultured on non-pathogenic Bacillus subtilis strain 67 versus age-matched worms cultured on the control lab food E. coli OP50. The goal was to identify genes regulated in response to differences in diet, which potentially confer immunity to later exposures to pathogenic Bacillus thuringiensis DB27.
Project description:The nematode Caenorhabditis elegans feeds on microbes in its natural environment. Some of these microbes are pathogenic and thus harmful to C. elegans. To minimize resulting fitness reductions, C. elegans has evolved various defence mechanisms including behavioural responses (e.g. avoidance behaviour) that reduce contact with the infectious microbes. In this study, we characterized the genetic architecture of natural variation in C. elegans avoidance behaviour against the infectious stages of the Gram-positive bacterium Bacillus thuringiensis. We performed an analysis of quantitative trait loci (QTLs) using recombinant inbred lines (RILs) and introgression lines (ILs) generated from a cross of two genetically as well as phenotypically distinct natural isolates N2 and CB4856. The analysis identified several QTLs that underlie variation in the behavioural response to pathogenic and/or non-pathogenic bacteria. One of the candidates is the npr-1 gene. This gene encodes a homolog of the mammalian neuropeptide receptor. Npr-1 was previously indicated to fully contribute to behavioural defence against the Gram-negative bacterium Pseudomonas aeruginosa and food patch-leaving behaviour on Escherichia coli. Interestingly, in our study, npr-1 is not the only gene mediating avoidance behaviour toward Bacillus thuringiensis. Moreover, our functional analyses show that npr-1 alleles appear to influence survival and avoidance behaviour toward Bacillus thuringiensis in exactly the opposite way than toward Pseudomonas aeruginosa. Our findings highlight the role of npr-1 in fine-tuning nematode behaviour in an ecological context depending on the microbe to which C. elegans is exposed. These opposite phenotypes reflect the diversity in innate immunity to pathogens. To understand the mechanism involved in these opposite phenotypes, we carried out a whole-genome transcriptomics study by RNA-Sequencing. This study includes two pathogens: Pseudomonas aeruginosa PA14 and Bacillus thuringiensis B-18247 (BT247), two strains: N2 and npr-1 (ur89), two time points (12 and 24h) and standard lab food E. coli OP50 as control. mRNA profiles of wild type (WT) and npr-1 (ur89) C.elegans exposed to either Bacillus thuringiensis B-18247, Pseudomonas aeruginosa PA14 or standard lab food E. coli OP50 at 12h or 24h were generated by deep sequencing, in double or triplicate, using Illumina HiSeq2000.
Project description:Transcriptional profiling of C. elegans young adult worms cultured on non-pathogenic Bacillus strain 67 versus versus age-matched worms cultured on the control lab food E. coli OP50. The goal was to identify genes regulated in response to differences in diet, which might confer immunity to later exposures to pathogenic Bacillus thuringiensis DB27. One-condition experiment. C. elegans young adults, cultured on : Bacillus strain 67 versus E. coli OP50. 4 biological replicates, including 2 dye-swaps.
Project description:Transcriptional profiling of C. elegans young adult worms exposed to pathogen Bacillus thuringiensis DB27 for 4 hours versus age-matched worms exposed to onctrol lab food E. coli OP50. The goal was to identify genes regulated in response to pathogen. The broader goal of study was to study evolution of pathogen response by comparing this expression profile to that obtained by exposing the nematode Pristionchus pacificus to the same pathogen. Other experiments which are a part of this study include expression profiling of C. elegans and P. pacificus on other pathogens including Staphylococcus aureus, Serratia marcescens, Xenorhabdus nematophila. Keywords: Expression profiling by array One-condition experiments. C. elegans young adults: Exposed to Bacillus thuringiensis DB27 versus exposed to E. coli OP50 : 4 hours. 3 biological replicates for each condition, including 1 dye-swap.
Project description:The nematode Caenorhabditis elegans feeds on microbes in its natural environment. Some of these microbes are pathogenic and thus harmful to C. elegans. To minimize resulting fitness reductions, C. elegans has evolved various defence mechanisms including behavioural responses (e.g. avoidance behaviour) that reduce contact with the infectious microbes. In this study, we characterized the genetic architecture of natural variation in C. elegans avoidance behaviour against the infectious stages of the Gram-positive bacterium Bacillus thuringiensis. We performed an analysis of quantitative trait loci (QTLs) using recombinant inbred lines (RILs) and introgression lines (ILs) generated from a cross of two genetically as well as phenotypically distinct natural isolates N2 and CB4856. The analysis identified several QTLs that underlie variation in the behavioural response to pathogenic and/or non-pathogenic bacteria. One of the candidates is the npr-1 gene. This gene encodes a homolog of the mammalian neuropeptide receptor. Npr-1 was previously indicated to fully contribute to behavioural defence against the Gram-negative bacterium Pseudomonas aeruginosa and food patch-leaving behaviour on Escherichia coli. Interestingly, in our study, npr-1 is not the only gene mediating avoidance behaviour toward Bacillus thuringiensis. Moreover, our functional analyses show that npr-1 alleles appear to influence survival and avoidance behaviour toward Bacillus thuringiensis in exactly the opposite way than toward Pseudomonas aeruginosa. Our findings highlight the role of npr-1 in fine-tuning nematode behaviour in an ecological context depending on the microbe to which C. elegans is exposed. These opposite phenotypes reflect the diversity in innate immunity to pathogens. To understand the mechanism involved in these opposite phenotypes, we carried out a whole-genome transcriptomics study by RNA-Sequencing. This study includes two pathogens: Pseudomonas aeruginosa PA14 and Bacillus thuringiensis B-18247 (BT247), two strains: N2 and npr-1 (ur89), two time points (12 and 24h) and standard lab food E. coli OP50 as control.
Project description:Transcriptional profiling of C. elegans nasp-1 / btr-1 mutant worms versus wild type N2 strain, both exposed to the bacterial pathogen Bacillus thuringiensis DB27. One-condition experiment. C. elegans nasp-1 / btr-1 mutant versus N2, exposed to Bacillus thuringiensis DB27. 3 biological replicates, including 1 dye-swaps.
Project description:Bacillus weihenstephanensis is a subspecies of the Bacillus cereus sensu lato group of spore forming bacteria known to cause food spoilage or food poisoning. The key distinguishing phenotype of B. weihenstephanensis is its ability to grow below 7°C or, from a food safety perspective, to grow and potentially produce toxins in a refrigerated environment. In order to gain insight into to the mechanistic basis of its psychrotolerant phenotype, as well as elucidate relevant aspects of its toxigenic profile, the proteome profiles of cells grown at either 6°C or 30°C were compared.
Project description:Comparison at t2 (two hours into post-exponential phase growth as analyzed by OD measurements) of global expression profiles from a Bacillus thuringiensis 407 delta-sinI delta-sinR double gene deletion strain versus a Bacillus thuringiensis 407 delta-sinI single gene deletion strain, to analyze global expression changes following deletion of the sinR transcriptional regulator gene in a sinI-negative background.
Project description:Transcriptional profiling of C. elegans nasp-1 / btr-1 mutant worms versus wild type N2 strain, both exposed to the bacterial pathogen Bacillus thuringiensis DB27.
Project description:Transcriptional profiling of C. elegans young adult worms exposed to pathogen Bacillus thuringiensis DB27 for 4 hours versus age-matched worms exposed to onctrol lab food E. coli OP50. The goal was to identify genes regulated in response to pathogen. The broader goal of study was to study evolution of pathogen response by comparing this expression profile to that obtained by exposing the nematode Pristionchus pacificus to the same pathogen. Other experiments which are a part of this study include expression profiling of C. elegans and P. pacificus on other pathogens including Staphylococcus aureus, Serratia marcescens, Xenorhabdus nematophila. Keywords: Expression profiling by array