sequences were edited to omit vec tors and low quality segments at 5 and 3 ends, then re moval of sequences shorter than 100 bp with SeqClean software. Sequence reads were assembled by CAP3 pro gram with default parameters. Then all the unigenes were annotated using BLASTx with a cut off value of 1. 0 �� e 5 by searching the UniProt database. GO KEGG EC annotation was per formed based on Annot8r platform. Hierarchical clustering of transcript accumulation was performed with Cluster software. Quantitative real time PCR verification and candidate TFs analysis Total RNA was extracted from QS and EG collected at four different developmental stages with the Trizol methods mentioned above. Primer pairs were designed with the Primer Express software.
Primer sequences of 11 candidate genes for verification were provided in Additional file 5, Table S1, and primer sequences of 10 TFs were provided in Additional file 6, Table S2. Single strand cDNA was synthesized with the prescription of the Anacetrapib Revert Aid TM first strand cDNA synthesis Kit. Then each cDNA sample was pre amplified using the citrus house keeping gene B actin and normalized for subsequent real time quantitative PCR. The PCR program differed in terms of the annealing temperature of each primer pair and the length of the predicted PCR products. The qRT PCR was per formed using the ABI 7500 Real Time System with the method as described by. And relative transcript change was analyzed by 2 c. Background Enterotoxigenic Escherichia coli is a Gram negative enteric pathogen, and an important cause of diarrhoea in human and animals.
As the most common bacterial enteric pathogen of human in the developing world, ETEC was thought to account for approximately 200 million diarrhoea episodes and 380,000 deaths annually reported by WHO in 2009. Therefore, the subject of ETEC in farm animals has always attracted much interest because it can be related to human diseases in many aspects. Furthermore, ETEC associated diarrhoea results in morbidity and mortality in neonatal and recently weaned piglets and is considered as one of the economically most important diseases in swine husbandry. ETEC express long, proteinaceous appendages or fim briae on their surface, which mediate adhesion to the gut epithelium. The virulence characteristics of ETEC are strongly dependent on the production of adhesins and enterotoxins.
Porcine ETEC strains isolated from diarrheic pigs express 5 different fimbriae, of which F4 and F18 fimbriae are the most prevalent. F4 fimbriae are typically associated with diarrhoea in neonatal pigs as well as in postweaning pigs and include F4ab, F4ac, and F4ad fimbrial var iants, of which the F4ac variant is the most common type. F18 fimbriae are typically associated with diarrhoea and edema disease of weaned pigs. The F18 fimbriae show a characteristic zigzag pattern and occur in two antigenic variants, F18ab and F18ac, of which F18ac is more readily expressed in vitro. The porcine IPEC J2 cell line