Project description:The purpose of this microarray experiment was to validate the Del-Mar 14K Chicken Integrated Systems Microarray for different chicken tissues and to determine the utility of this chicken cDNA microarray for other closely related and more distant avian species. The Del-Mar 14 K array was constructed from cDNAs amplified from EST clones sequenced from five normalized chicken cDNA libraries derived from neuroendocrine (5,929), abdominal fat (4,800), liver (2,635), skeletal muscle (2,398), reproductive tract (2,008), 387 long (70mer) oligonucleotides and 72 quality control spots. The array contains 17,770 cDNA clones, where protein matches were found by BlastX analysis for 68% of chicken contigs and 46% of singleton sequences represented on the array. A reference RNA design was used for the hybridization of total RNA from four chicken tissues (liver, abdominal fat, breast muscle and hypothalamus) and the cross-species hybridization (CSH) of total RNA from tissue from birds representing four orders of the Class Aves [Galliformes (chicken, Coturnix quail and domestic turkey), Anseriformes (Peking duck), Falconiformes (American kestrel) and Passeriformes (American tree sparrow)]. A reference RNA pool was made from an equal amount of high-quality total RNA extracted from chicken liver, abdominal fat, breast muscle and hypothalamus. Each of the 43 microarrays was co-hybridized with Cy3-labeled cDNA targets from one of the avian tissue samples and Cy5-labled cDNA targets from the reference chicken RNA pool. Loess-normalized data were used to determine the number of cDNAs expressed in chicken tissues and the number of genes (cDNAs) detectable by cross-hybridization with various avian tissue samples. The Cy5-labeled reference samples were used to determine the coefficient of variation across the 43 microarrays. This study shows a remarkably high level of cross hybridization of Cy3-labeled cDNA targets from a wide range of avian species to the Del-Mar 14K microarray, where 38 to 62% of the cDNA probes on the chicken array (genes) were detectable. Keywords: Transcriptional profiling, Del-Mar 14K Chicken Integrated Systems Microarray validation, multi-tissues, cross-species hybridization, class Aves
Project description:We carried out a comparative genomic analysis of 48 avian species to identify avian-specific highly conserved elements (ASHCEs). We performed genome-wide chromatin immunoprecipitation sequencing (ChIP-seq) for three enhancer-associated histone modifications (H3K4me1, H3K27ac, H3K27me3), to investigate dynamic regulatory roles of ASHCEs in chicken development. We found that all three enhancer-associated histone marks are enriched in ASHCEs compared to the whole genome background.
Project description:To investigate the transcriptional response in whole blood from administration of the Cytomegolovirus vaccine vector against heterologous avian flu
Project description:Sanhong Liu, Shigui Ruan & Xinan Zhang. Nonlinear dynamics of avian influenza epidemic models. Mathematical Biosciences 283 (2017).
Avian influenza is a zoonotic disease caused by the transmission of the avian influenza A virus, such as H5N1 and H7N9, from birds to humans. The avian influenza A H5N1 virus has caused more than 500 human infections worldwide with nearly a 60% death rate since it was first reported in Hong Kong in 1997. The four outbreaks of the avian influenza A H7N9 in China from March 2013 to June 2016 have resulted in 580 human cases including 202 deaths with a death rate of nearly 35%. In this paper, we construct two avian influenza bird-to-human transmission models with different growth laws of the avian population, one with logistic growth and the other with Allee effect, and analyze their dynamical behavior. We obtain a threshold value for the prevalence of avian influenza and investigate the local or global asymptotical stability of each equilibrium of these systems by using linear analysis technique or combining Liapunov function method and LaSalle's invariance principle, respectively. Moreover, we give necessary and sufficient conditions for the occurrence of periodic solutions in the avian influenza system with Allee effect of the avian population. Numerical simulations are also presented to illustrate the theoretical results.
Project description:Sanhong Liu, Shigui Ruan & Xinan Zhang. Nonlinear dynamics of avian influenza epidemic models. Mathematical Biosciences 283 (2017).
Avian influenza is a zoonotic disease caused by the transmission of the avian influenza A virus, such as H5N1 and H7N9, from birds to humans. The avian influenza A H5N1 virus has caused more than 500 human infections worldwide with nearly a 60% death rate since it was first reported in Hong Kong in 1997. The four outbreaks of the avian influenza A H7N9 in China from March 2013 to June 2016 have resulted in 580 human cases including 202 deaths with a death rate of nearly 35%. In this paper, we construct two avian influenza bird-to-human transmission models with different growth laws of the avian population, one with logistic growth and the other with Allee effect, and analyze their dynamical behavior. We obtain a threshold value for the prevalence of avian influenza and investigate the local or global asymptotical stability of each equilibrium of these systems by using linear analysis technique or combining Liapunov function method and LaSalle's invariance principle, respectively. Moreover, we give necessary and sufficient conditions for the occurrence of periodic solutions in the avian influenza system with Allee effect of the avian population. Numerical simulations are also presented to illustrate the theoretical results.
Project description:A comparative genomic approach was used to identify large sequence polymorphisms among Mycobacterium avium isolates obtained from a variety of host species. DNA microarrays were used as a platform for comparing mycobacteria field isolates with the sequenced bovine isolate Mycobacterium avium subsp. paratuberculosis (Map) K10. ORFs were classified as present or divergent based on the relative fluorescent intensities of the experimental samples compared to Map K10 DNA. Map isolates cultured from cattle, bison, sheep, goat, avian, and human sources were hybridized to the Map microarray. Three large deletions were observed in the genomes of four Map isolates obtained from sheep and four clusters of ORFs homologous to sequences in the Mycobacterium avium subsp. avium (Maa) 104 genome were identified as being present in these isolates. One of these clusters encodes glycopeptidolipid biosynthesis enzymes. One of the Map sheep isolates had a genome profile similar to a group of Mycobacterium avium subsp. silvaticum (Mas) isolates which included four independent laboratory stocks of the organism traditionally identified as Maa strain 18. Genome diversity in Map appears to be mostly restricted to large sequence polymorphisms that are often associated with mobile genetic elements. Keywords: Comparative genomic hybridization