Project description:Background: Gastrointestinal nematodes are a serious cause of morbidity and mortality in grazing ruminants. The major ovine defence mechanism is acquired immunity, which develops over time in response to infection. Nematode resistance varies both within and between breeds and is moderately heritable (h ~ 0.3). A detailed understanding of the genes and mechanisms involved in protective immunity, and the factors that regulate this response, is required to aid future breeding strategies as well as the development of effective and sustainable nematode control methods. The aim of this study was to compare the abomasal lymph node transcriptome of resistant and susceptible lambs in order to determine biological processes differentially expressed between resistant and susceptible lambs. Results: Scottish Blackface lambs, with divergent phenotypes for resistance, were challenged with 30,000 Teladorsagia circumcincta larvae (L3), and abomasal lymph node recovered at 7 and 14 days post-infection (dpi). High-throughput sequencing of abomasal lymph node cDNA was used to quantitatively sample the transcriptome with an average of 32 million reads per sample. A total of 194 and 144 genes were differentially expressed between resistant and susceptible lambs at 7 and 14 dpi respectively. Differentially expressed networks and biological processes were identified using Ingenuity Pathway Analysis. Resistant animals appear to generate a more rapid immune response as at 7 dpi processes relating to homing of lymphocytes, leukocyte migration and migration of antigen presenting cells were up-regulated. In susceptible animals this response appears to be delayed until approximately 14 dpi. Twenty-four Single Nucleotide Polymorphims (SNP), within 11 differentially expressed genes were tested for association with gastrointestinal nematode resistance in the Scottish Blackface lambs. Four SNPs in two genes (SLC30A2, and ALB) were suggestively associated with faecal egg count. Conclusions: A large number of genes were differentially expressed in the abomasal lymph node of resistant and susceptible lambs responding to gastrointestinal nematode challenge. Resistant Scottish Blackface lambs appear to generate a more rapid immune response to T. circumcincta. In susceptible lambs this response appears to be delayed until approximately 14 days post infection. SNP in two differentially expressed genes were suggestively associated with faecal egg count indicating that differentially expressed genes can be considered as candidate loci for mediating nematode resistance.

Project description:The gastrointestinal nematode Ostertagia ostertagi is one of major causal agents that contribute to production inefficiency in cattle industry in the temperate region of the world. One of pathophysiological factors that lead to reduced weight gain and milk yield is altered gastrointestinal functions, resulting from considerable tissue damage in the abomasal mucosa during infections. Protective immunity to Ostertagia ostertagi infections in cattle develops very slowly. Resistance to reinfection becomes manifest only after a prolonged period of exposure. Mechanisms underlying the development of protective immunity remain largely unexplored. Immune animals, with significantly reduced worm burdens, were developed after multiple drug-attenuated experimental infections and were compared to the primary infected group and their respective uninfected controls. In this study, transcriptomic analysis identified 3 signaling pathways, the complement system, leukocyte extravasation and acute phase responses, significantly impacted during both primary and repeat infections. The markedly increased mRNA levels of complement components C3, factor B (CFB), and factor I (CFI) in the abomasal mucosa of the infected cattle were confirmed using quantitative PCR. Western blot analysis established the presence of elevated levels of activated C3 proteins in the mucosa. One of the iniators of local complement activation could be related with secretory IgA and IgM because infections significantly upregulated expression of J chain (IGJ) as well as polymeric Ig receptor (PIGR) and an IgM-specific receptor (FAIM3), suggesting sustained increase in both synthesis and transepithelial transport of IgA and IgM during the infection. The elevated levels of pro-inflammatory cytokines, such as IL-4 and IL-1Î², during the infection may be involved in gene regulation of complement components. Our data suggested enhanced tissue repair and mucin secretion in immune animals may also contribute to protective immunity. Our results presented the first piece of evidence that local complement activation may be involved in the development of long term protective immunity and provided a novel mechanistic insight into resistance against Ostertagia ostertagi in cattle. There were four treatment groups: naive control (never infected), primary infection, drug-attenuated control, and drug-attenuated 5th reinfection. Each group had 4 biolgical replicates. A total of 16 arrays were used for this experiment. The 2 major contrast were 1). The primary infection vs naive control; and 2). The drug-attenuated 5th reinfection vs the drug-attenuated control.

Project description:The gastrointestinal nematode Ostertagia ostertagi is one of major causal agents that contribute to production inefficiency in cattle industry in the temperate region of the world. One of pathophysiological factors that lead to reduced weight gain and milk yield is altered gastrointestinal functions, resulting from considerable tissue damage in the abomasal mucosa during infections. Protective immunity to Ostertagia ostertagi infections in cattle develops very slowly. Resistance to reinfection becomes manifest only after a prolonged period of exposure. Mechanisms underlying the development of protective immunity remain largely unexplored. Immune animals, with significantly reduced worm burdens, were developed after multiple drug-attenuated experimental infections and were compared to the primary infected group and their respective uninfected controls. In this study, transcriptomic analysis identified 3 signaling pathways, the complement system, leukocyte extravasation and acute phase responses, significantly impacted during both primary and repeat infections. The markedly increased mRNA levels of complement components C3, factor B (CFB), and factor I (CFI) in the abomasal mucosa of the infected cattle were confirmed using quantitative PCR. Western blot analysis established the presence of elevated levels of activated C3 proteins in the mucosa. One of the iniators of local complement activation could be related with secretory IgA and IgM because infections significantly upregulated expression of J chain (IGJ) as well as polymeric Ig receptor (PIGR) and an IgM-specific receptor (FAIM3), suggesting sustained increase in both synthesis and transepithelial transport of IgA and IgM during the infection. The elevated levels of pro-inflammatory cytokines, such as IL-4 and IL-1β, during the infection may be involved in gene regulation of complement components. Our data suggested enhanced tissue repair and mucin secretion in immune animals may also contribute to protective immunity. Our results presented the first piece of evidence that local complement activation may be involved in the development of long term protective immunity and provided a novel mechanistic insight into resistance against Ostertagia ostertagi in cattle.

Project description:Black cattle is a new breed of beef cattle developed by combining modern biotechnologies such as somatic cell cloning and conventional breeding methods. To provide new ideas for improving meat quality and generating new breeds of cattle, the important candidate genes affecting fat deposition in two kinds of cattle were identified. Eighteen months Black cattles and Luxi cattles were randomly assigned into two environmental. The longissimus dorsi muscle were collected on Black cattle and Luxi cattle,for analyses including fatty acid determinationrs, high-throughput sequencing metagenomics, qRT-PCR expression profile and western blot.The ratio of unsaturated fatty acids to saturated fatty acids was 1.37:1 and 1.24:1 in the muscle tissues of Black cattle and Luxi cattle, respectively. The results of RNA-Seq analysis revealed 1,415 DEGs(fold change ≥ ± 2, P<0.05) between the longissimus dorsi of Black cattle and yellow cattle. A total of 939 genes were upregulated, and the other 476 genes were downregulated. With GO enrichment analysis, it was found that the identified DEGs were significantly enriched in biological regulation, regulation of the Wnt signaling pathway, negative regulation of the Wnt signaling pathway, cAMP metabolic process, fat cell differentiation, and brown fat cell differentiation, among other functions. Regulation of lipolysis in adipocytes, AMPK signaling pathway, adipocytokine signaling pathway and PPAR signaling pathway in the KEGG pathway database were significantly enriched. PPI network analysis showed that the downregulated genes FABP4, ADIPOQ, PLIN1, PLIN2 and LIPE were closely linked to other DEGs and were the key sites of multiple metabolic pathways. Combined with qRT-PCR and protein expression profile analysis, the expression level of fat acid metabolism related genes (FABP4, ADIPOQ) in black cattle was high and the difference was significant. Changes in the expression of fatty acid metabolism-related genes in Black cattle and Luxi cattle were analyzed and important candidate marker genes (such as ADIPOQ and FABP4) that affect fat deposition were identified in order to provide a genetic basis for the efficient breeding of production performance, establish a molecular marker database for local cattle breeds and support the cultivation of new breeds.

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Gastrointestinal nematode of cattle

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