Project description:This experiment was undertaken to document changes in gene expression in the skin of tick-resistant Brahman (Bos indicus) and tick-susceptible Holstein-Friesian (Bos taurus) cattle prior to, and following, infestation with the cattle tick Rhipicephalus (Boophilus) microplus Keywords: Disease state analysis
Project description:This experiment was undertaken to document changes in gene expression in the skin of tick-resistant Brahman (Bos indicus) and tick-susceptible Holstein-Friesian (Bos taurus) cattle prior to, and following, infestation with the cattle tick Rhipicephalus (Boophilus) microplus Experiment Overall Design: RNA was extracted from skin samples of tick-naïve cattle (animals with no previous R.microplus exposure) and tick-infested cattle after a period of successive, heavy infestations with R. microplus. Skin samples taken from tick-infested animals were taken at sites where tick larvae (approximately 24 h old) were attached to the skin sample. Skin samples were of 8 mm diameter and full skin thickness (approximately 10 mm). RNA samples from 12 animals (3 tick-naive Holstein-Friesian, 3 tick-naive Brahman, 3 tick-infested Holstein-Friesian and 3 tick-infested Brahman) were processed and hybridised to individual slides.
Project description:Tropical theileriosis in a cattle disease of global economic importance, caused by the tick-borne protozoan parasite Theileria annulata. Conventional control strategies are failing to contain the disease and an attractive alternative is the use of pre-existing genetic resistance or tolerance. However, tropical theileriosis tolerant cattle are less productive than some susceptible breeds. To combine resistance and production traits requires an understanding of the mechanisms involved in resistance. Therefore, we have compared the response of monocytes derived from tolerant (Sahiwals, Bos indicus) and susceptible (Holstein-Friesians, B. taurus) cattle to in vitro infection with T. annulata. Over 150 genes exhibited breed-specific differential expression during the course of infection and nearly one third were differentially expressed in resting cells, implying that there are inherent differences between monocytes from the breeds. Fifty sequences currently only match ESTs or are unique to the library used to generate the microarray. The differential expression of a selection of genes was validated by quantitative RT-PCR, e.g. CD9, prion protein and signal-regulatory protein alpha. A large proportion of the differentially expressed genes encode proteins expressed on the plasma membrane or in the extracellular space and cell adhesion was one of the major Gene Ontology biological processes identified. We therefore hypothesise that the breed-specific tolerance of Sahiwal cattle compared to Holstein-Friesians is due to the interaction of infected cells with other immune cells, which influences the immune response generated against T. annulata infection. The BoMP microarray is available from the ARK-Genomics facility (www.ark-genomics.org).
Project description:High yielding dairy cattle undergo a state of NEB (negative energy balance) during the post-partum period when energy demand for lactation and maintenance exceeds energy intake. During this period in order to counteract NEB the liver under goes extensive metabolic and physiological change resulting in alteration in hepatic genes and miRNAs expression. We used Affymetrix Multispecies miRNA-2_0 Array with miRBase version 15 coverage to assess the liver miRNA expression in SNEB (severe NEB) and MNEB (mild NEB) Holstein Friesian cattle during the post-partum period. A NEB model of Holstein Friesian was established such that 12 post-partum cattle were randomly assigned to MNEB and SNEB groups depending on different feeding and milking regimes
Project description:Comparative microarray analysis of Rhipicephalus (Boophilus) microplus expression profiles of larvae pre-attachment and feeding adult female stages on Bos indicus and B. taurus cattle Global analysis of gene expression changes in R. microplus during larval, pre-attachment and early adult stages of its life cycle feeding on Bos indicus and Bos taurus cattle were compared using gene expression microarray analysis. Among the 13 601 R. microplus transcripts from BmiGI Version 2 we identified 297 up and 17 down regulated transcripts were differentially expressed between R. microplus feeding on tick resistant cattle [Bos indicus (Brahman)] compared to R. microplus feeding on tick susceptible cattle [Bos taurus (Holstein-Friesian)]. These include genes encoding enzymes involved in primary metabolism, and genes related to stress, defence, cell wall modification, cellular signaling, receptor and cuticle. Microarrays were validated by qRT-PCR analysis of selected transcripts including the validation of three housekeeping genes. The analysis of all tick stages under survey suggested a coordinated regulation of defence proteins, proteases, and protease inhibitors to achieve successful attachment and survival of R. microplus on different host breeds particularly Bos indicus cattle.
Project description:High yielding dairy cattle undergo a state of NEB (negative energy balance) during the post-partum period when energy demand for lactation and maintenance exceeds energy intake. During this period in order to counteract NEB the liver under goes extensive metabolic and physiological change resulting in alteration in hepatic genes and miRNAs expression. We used Affymetrix Multispecies miRNA-2_0 Array with miRBase version 15 coverage to assess the liver miRNA expression in SNEB (severe NEB) and MNEB (mild NEB) Holstein Friesian cattle during the post-partum period.