Project description:Campylobacter jejuni (C. jejuni) is a zoonotic pathogen that causes human diarrhea worldwide. Chickens are a natural reservoir of C. jejuni. Understanding the host response to C. jejuni infection at the molecular level will lay the foundation to control human campylobacterosis by reducing food contamination. Two distinct genetic lines, resistant (line A) and susceptible (line B) to C. jejuni colonization, were utilized to profile the host response to C. jejuni infection using an Agilent chicken 44K microarray. Day-old chickens were challenged orally with C. jejuni and spleens collected for total RNA 7 days post-challenge. Twenty infected samples with highest (a) or lowest bacterial number (b) in cecal content and twenty non-infected (c) in each line were randomly pooled into four biological replicates. The pair comparisons among these three groups within each line were analyzed. The signal intensity of each gene was normalized using LOWESS method. A mixed model was used to identify differentially expressed genes by SAS (P < 0.001). This was opposite to previous cecal tonsil microarray result. There were 468, 743, and 939 genes differentially expressed between groups a and c, groups a and b, and groups b and c in line A, respectively, and 201, 37, 126 genes in line B, respectively. More differentially expressed genes in spleen in line A than in line B were found. The results indicated that significantly different response to C. jejuni infection occurred between resistant and susceptible chicken lines, and the effects of interaction between genetics and tissue should be considered. Chickens in two broiler lines were inoculated with 10^5 cfu C. jejuni on one day after hatch. The cecal content and cecal tonsil was collected and bacterial number in cecal content was counted on day 7 after inoculation. Twenty samples were separated into 3 groups (high burden, low burden, and control) based on bacterial burden of cecal content in each line, 5 samples were mixed randomly into one pool. A dual color, balanced design was carried on for all samples. Three comparisons were used in each line, non-infected/susceptible, susceptible/resistant, resistant/non-infected, totally, four biological replicates in each line. A Dye swap was used in each pair of comparisons including AN/AS, AS/AR, AR/AN; BN/BS, BS/BR, and BR/BN. Background subtracted signal intensity were collected from 24 arrays and normalized for data analysis.
Project description:Campylobacter jejuni is a common cause of diarrheal disease worldwide. Human infection typically occurs through the ingestion of contaminated poultry products. We previously demonstrated that an attenuated Escherichia coli live vaccine strain expressing the C. jejuni N-glycan on its surface reduces the Campylobacter load in more than 50% of vaccinated leghorn and broiler birds to undetectable levels (responder birds), whereas the remainder of the animals were still colonized (non-responders). To understand the underlying mechanism, we conducted 3 larger scale vaccination and challenge studies using 135 broiler birds and found a similar responder/non responder effect. The submitted data were used for a genome-wide association study of the chicken responses to glycoconjugate vaccination against Campylobacter jejuni.
Project description:It is essential to understand host response to Campylobacter jejuni infection in order to genetically improve resistance to its colonization in chickens. A custom Agilent chicken 44K array was used to examine gene expression profiles after Campylobacter jejuni infection of two broiler lines (A and B). Day-old chicks were orally inoculated with C. jejuni. After day 7 post-infection, the cecal tonsil was collected for total RNA isolation and cecal content for bacteria burden quantification. Twenty highest and lowest bacterial burden birds and non-infected birds within each line were used to pool four biological replicates for each group. The pair comparisons among high, low bacterial burden, and non-infected group were used. The signal intensity of each gene was normalized by LOWESS method. A mixed model including the fixed effects of dye, line, treatment and line × treatment interaction, and random effects of slide and array was used to identify differentially expressed genes at P < 0.001 by SAS program. Within line A, there were 61, 163, and 90 genes significantly differentially expressed between high and low bacterial burden, high bacterial burden and non-infected group, and low bacterial burden and non-infected group, respectively; 2637, 1684, 561 genes within line B, respectively. The results suggested that genetics, treatment and genetics × treatment interaction played important role in gene regulation of C. jejuni infection. The findings in the current study will lead the identification of potential candidate genes for genetic resistance to C. jejuni infection in chickens. Keywords: diease state analysis
Project description:Campylobacter jejuni (C. jejuni) is a zoonotic pathogen that causes human diarrhea worldwide. Chickens are a natural reservoir of C. jejuni. Understanding the host response to C. jejuni infection at the molecular level will lay the foundation to control human campylobacterosis by reducing food contamination. Two distinct genetic lines, resistant (line A) and susceptible (line B) to C. jejuni colonization, were utilized to profile the host response to C. jejuni infection using an Agilent chicken 44K microarray. Day-old chickens were challenged orally with C. jejuni and spleens collected for total RNA 7 days post-challenge. Twenty infected samples with highest (a) or lowest bacterial number (b) in cecal content and twenty non-infected (c) in each line were randomly pooled into four biological replicates. The pair comparisons among these three groups within each line were analyzed. The signal intensity of each gene was normalized using LOWESS method. A mixed model was used to identify differentially expressed genes by SAS (P < 0.001). This was opposite to previous cecal tonsil microarray result. There were 468, 743, and 939 genes differentially expressed between groups a and c, groups a and b, and groups b and c in line A, respectively, and 201, 37, 126 genes in line B, respectively. More differentially expressed genes in spleen in line A than in line B were found. The results indicated that significantly different response to C. jejuni infection occurred between resistant and susceptible chicken lines, and the effects of interaction between genetics and tissue should be considered.
Project description:The gut of chicken is mostly colonised with Campylobacter jejuni and with 100 fold less C. coli. The competitive ability of C. coli OR12 over C. jejuni OR1 has been examined in experimental broiler chickens following the observation that C. coli replaced an established C. jejuni intestinal colonisation within commercial chicken flocks reared outdoors (El-Shibiny, A., Connerton, P.L., Connerton, I.F., 2005. Enumeration and diversity of campylobacters and bacteriophages isolated during the rearing cycles of free-range and organic chickens. Applied Environmental Microbiology. 71, 1259-1266).
Project description:Chicken 60-mer oligonucleotide microarray, including 39854 cDNA and ESTs, entire Marek’s disease virus and avian influenza virus genomes, and 150 chicken microRNAs, was developed. Cecal tonsil, ileum, liver and spleen from 6 chickens were selected for hybridization to validate the microarray performance. There are 2886, 2886, 2660, 358, 3208 3355, and 3710 genes significantly expressed between liver and spleen, spleen and cecal tonsil, cecal tonsil and ileum, liver and cecal tonsil, liver and ileum, spleen and ileum at the P<10-7. Number of tissue specific genes for cecal tonsil, ileum, liver and spleen was 95, 71, 535, and 108, respectively with p < 10-7. More than 95% of spots had high SNR (>10). Keywords: characteristics of newly developed microarray using different normal tissue
Project description:Relative expression levels of mRNAs in chicken cecal epithelia experimentally infected with Eimeria tenella were measured at 4.5 days post-infection. Two weeks old chickens were uninfected (negative control) or were orally inoculated with sporulated oocysts of Eimeria tenella. Cecal epithelia samples were collected from >12 birds in infected or uninfected group at 4.5 d following infections, in which samples from 4 birds were pooled together to form a total 3 biological replicates in each group. Parasite merozoites were also collected from four infected chickens at 5 d after infections. Uninfected control samples, merozoites and infection group samples were selected for RNA extraction and hybridization on Affymetrix microarrays. We used Affymetrix GeneChip chicken genome arrays to detail the chicken cecal epithelia gene expression in the control and E. tenella-infected birds. Infected, uninfected chicken cecal epithelia and merozoites were selected for RNA extraction and hybridization with Affymetrix microarrays. Our goal was to analyze global transcriptome changes in chicken cecal mucous membranes in response to E. tenella infection in vivo. We used infected (T1,T2,T3; three biological replicates) and uninfected (Neg1, Neg2, Neg3; three biological replicates) samples to identify genes that were differentially expressed. Meanwhile, RNA and probes were also prepared from parasite merozoites (Mzt) from infected samples (Mzt) and used as an additional control in microarray hybridization.
Project description:Relative expression levels of mRNAs in chicken cecal epithelia experimentally infected with Eimeria tenella were measured at 4.5 days post-infection. Two weeks old chickens were uninfected (negative control) or were orally inoculated with sporulated oocysts of Eimeria tenella. Cecal epithelia samples were collected from >12 birds in infected or uninfected group at 4.5 d following infections, in which samples from 4 birds were pooled together to form a total 3 biological replicates in each group. Parasite merozoites were also collected from four infected chickens at 5 d after infections. Uninfected control samples, merozoites and infection group samples were selected for RNA extraction and hybridization on Affymetrix microarrays. We used Affymetrix GeneChip chicken genome arrays to detail the chicken cecal epithelia gene expression in the control and E. tenella-infected birds.
Project description:Chromosomal structural variation can cause alterations in gene dosage and gene regulation between genomes. Structural variants producing a change in the number of copies of a genomic region are termed copy number variants (CNVs). CNVs have been demonstrated to have causative effects on both Mendelian and complex traits, including susceptibility to infectious diseases. We are interested in mapping CNVs to domesticated chicken breeds to help determine structural variation between genomes that influences economically important traits. For this study, Fayoumi, Leghorn, Line A broiler and Line B broiler chicken were chosen. Fayoumi and Leghorn chickens were selected as these two breeds harbor different responses certain pathogens like Avian Influenza Virus and coccidiosis; Broiler Line A and Line B indivduals were chosen as they harbor different intestinal colonization loads to the bacterium Campylobacter jejuni. Campylobacter genetic Line A and genetic Line B are from a commercial producer have been previously described as either resistant (Line A) or susceptible (Line B). Highly inbred chicken lines Fayoumi M15.2 (n=6) and Leghorn GHs6 (n=6) and broilers from Line A (n=24 individuals in pools of 4) and Line B (n=24 individuals in pools of 4)were subjected to array Comparative Genomic Hybridization (aCGH). Each sample was normalized to a Red Jungle Fowl reference. CNVs for each individual and between lines were determined. The major goal of this study was to discover and characterize CNVs in chickens to further narrow in on Quantitative Trait Loci (QTLs) affecting disease response.
Project description:Chromosomal structural variation can cause alterations in gene dosage and gene regulation between genomes. Structural variants producing a change in the number of copies of a genomic region are termed copy number variants (CNVs). CNVs have been demonstrated to have causative effects on both Mendelian and complex traits, including susceptibility to infectious diseases. We are interested in mapping CNVs to domesticated chicken breeds to help determine structural variation between genomes that influences economically important traits. For this study, Fayoumi, Leghorn, Line A broiler and Line B broiler chicken were chosen. Fayoumi and Leghorn chickens were selected as these two breeds harbor different responses certain pathogens like Avian Influenza Virus and coccidiosis; Broiler Line A and Line B indivduals were chosen as they harbor different intestinal colonization loads to the bacterium Campylobacter jejuni. Campylobacter genetic Line A and genetic Line B are from a commercial producer have been previously described as either resistant (Line A) or susceptible (Line B). Highly inbred chicken lines Fayoumi M15.2 (n=6) and Leghorn GHs6 (n=6) and broilers from Line A (n=24 individuals in pools of 4) and Line B (n=24 individuals in pools of 4)were subjected to array Comparative Genomic Hybridization (aCGH). Each sample was normalized to a Red Jungle Fowl reference. CNVs for each individual and between lines were determined. The major goal of this study was to discover and characterize CNVs in chickens to further narrow in on Quantitative Trait Loci (QTLs) affecting disease response. For the test DNA in Fayoumi and Leghorn, samples from 6 inbred Fayoumi and 6 inbred Leghorn individuals were used; For the test DNA in the Campylobacter genetic lines, samples from 24 individual broilers of Line A (in pools of 4) and 24 individual broilers of Line B (in pools of 4) were used. For the reference DNA, Red Jungle Fowl line UCD001 was used from a self-self hybridization.