Philip Griebel
University of Saskatchewan, School of Public Health, Faculty Member
Research Interests:
Mycobacterium avium subsp. Paratuberculosis (MAP) is the causal agent of Johne’s disease (JD), a chronic intestinal disease affecting ruminants worldwide. This study investigated miRNA expression in jejunal intestine (JE) and jejunal... more
Mycobacterium avium subsp. Paratuberculosis (MAP) is the causal agent of Johne’s disease (JD), a chronic intestinal disease affecting ruminants worldwide. This study investigated miRNA expression in jejunal intestine (JE) and jejunal lymph nodes (JELN), and the potential regulatory roles of miRNAs during JD progression. JE and JELN tissues were collected from 5 MAP positive (JD subclinical stage) Holstein cows and 5 MAP negative cows. Following miRNA sequencing, bioinformatic processing with a standard pipeline and functional analysis with ClueGo, 272 and 333 miRNAs were identified in JE and JELN, respectively. Compared with MAP negative cows, 13 and 71 miRNAs were differently expressed (DE) (P < 0.05) in MAP infected JE and JELN, respectively. The most up-regulated and down-regulated miRNAs were bta-miR-485 (fold change = 6.18) and bta-miR-451 (fold change = -6.81), and bta-miR-331-5p (fold change = 35.56) and bta-miR-2285bk (fold change = -61.25) in JE and JELN, respectively. I...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
The majority of pathogens enter the body through mucosal surfaces and it is now evident that mucosal immunity can provide effective disease protection. However, the induction of mucosal immunity will require efficient targeting of mucosal... more
The majority of pathogens enter the body through mucosal surfaces and it is now evident that mucosal immunity can provide effective disease protection. However, the induction of mucosal immunity will require efficient targeting of mucosal vaccines to appropriate mucosa‐associated lymphoid tissue. An animal model, based upon the surgical preparation of sterile intestinal ‘loops’ (blind‐ended segments of intestine), was developed to evaluate mucosal and systemic immune responses to enteric vaccines in ruminants. The effectiveness of end‐to‐end intestinal anastomoses was evaluated and fetal surgery did not disrupt normal intestinal function in lambs up to 6–7 months after birth. The immunological competence of Peyer’s patches (PP) within the intestinal ‘loops’ was evaluated with a human adenovirus 5 vector expressing the gD gene of bovine herpesvirus‐1. This vaccine vector induced both mucosal and systemic immune responses when injected into intestinal ‘loops’ of 5–6‐week‐old lambs. An...
Research Interests:
Research Interests:
Beta-defensin 103 (DEFB103) shares little homology with 8 other members of the bovine beta-defensin family and in other species DEFB103 protein has diverse functions, including antimicrobial activity, a chemoattractant for dendritic... more
Beta-defensin 103 (DEFB103) shares little homology with 8 other members of the bovine beta-defensin family and in other species DEFB103 protein has diverse functions, including antimicrobial activity, a chemoattractant for dendritic cells, enhancing epithelial wound repair and regulating hair colour. Expression of the bovine DEFB103 gene was surveyed in 27 tissues and transcript was most abundant in tissues with stratified squamous epithelium. Oral cavity epithelial tissues and nictitating membrane consistently expressed high levels of DEFB103 gene transcript. An age-dependent decrease (P &amp;amp;lt; 0.05) in DEFB103 gene expression was only observed for buccal epithelium when comparing healthy 10- to 14-day-old and 10- to 12-month-old calves. A bovine herpesvirus-1 respiratory infection did, however, significantly (P &amp;amp;lt; 0.05) up-regulate DEFB103 gene expression in the buccal epithelium of 6- to 8-month-old calves. Finally, DEFB103 transcript was low in lymph nodes draining the skin and at the limit of detection in other internal organs such as lung, intestine and kidney. Affinity-purified rabbit antisera to bovine DEFB103 was used to identify cells expressing DEFB103 protein within tissues with stratified squamous epitheliums. DEFB103 protein was most abundant in basal epithelial cells and was present in these cells prior to birth. Beta-defensins have been identified as regulators of dendritic cell (DC) chemokine responses and we observed a close association between DCs and epithelial cells expressing DEFB103 in both the fetus and newborn calf. In conclusion, bovine DEFB103 gene expression is most abundant in stratified squamous epithelium with DEFB103 protein localised to basal epithelial cells. These observations are consistent with proposed roles for DEFB103 in DC recruitment and repair of stratified squamous epithelium.
Research Interests:
Research Interests:
Research Interests: Immune response, Biology, Innate immunity, Medicine, Diarrhea, and 15 moreBiological Sciences, General, Female, Animals, Comparative Analysis, Fisheries Sciences, Jejunum, Cattle, Immune system, Coronavirus, Innate Immune System, innate immune response, cattle diseases, Coronavirus infections, and Medical and Health Sciences
Research Interests:
Research Interests:
Research Interests:
We previously reported that CD21(+) B cells purified from bovine blood do not respond to CpG-ODN stimulation unless either CD14(+) monocytes or B-cell Activating Factor (BAFF), a cytokine produced by activated monocytes, are present. In... more
We previously reported that CD21(+) B cells purified from bovine blood do not respond to CpG-ODN stimulation unless either CD14(+) monocytes or B-cell Activating Factor (BAFF), a cytokine produced by activated monocytes, are present. In this report, we present evidence that CD14(+) monocytes are critical for CpG-specific lymphocyte proliferation within the peripheral blood mononuclear cell (PBMC) population but that this response is not mediated by soluble factors produced by CpG-activated monocytes. We further determine that bovine monocytes stimulated with IFN-γ induce expression of the BAFF gene and that recombinant IFN-γ and BAFF induced robust B cell activation when cultured in the absence of CpG ODN. These data suggest that CpG-stimulated monocytes may indirectly promote B cell activation by promoting release of cytokines and/or other soluble factors from accessory cells which in turn act on CpG-stimulated B cells to promote antigen-independent and T cell independent B cell activation. Understanding the T cell independent signals that induce B cell activation has important implications for understanding B cell development in locations where T cells are limited and in understanding polyclonal B cell activation that may contribute to autoimmune diseases.
Research Interests:
Antibodies are critical effector molecules of the humoral immune system. Upon infection or vaccination, populations of antibodies are generated which bind to various regions of the invading pathogen or exogenous agent. Defining the... more
Antibodies are critical effector molecules of the humoral immune system. Upon infection or vaccination, populations of antibodies are generated which bind to various regions of the invading pathogen or exogenous agent. Defining the reactivity and breadth of this antibody response provides an understanding of the antigenic determinants and enables the rational development and assessment of vaccine candidates. High-resolution analysis of these populations typically requires advanced techniques such as B cell receptor repertoire sequencing, mass spectrometry of isolated immunoglobulins, or phage display libraries that are dependent upon equipment and expertise which are prohibitive for many labs. High-density peptide microarrays representing diverse populations of putative linear epitopes (immunoarrays) are an effective alternative for high-throughput examination of antibody reactivity and diversity. While a promising technology, widespread adoption of immunoarrays has been limited by ...
Research Interests:
The α- and β-adrenergic receptors (ARs) bind the stress hormones epinephrine (E), norepinephrine (NE), and dopamine and activate diverse physiological responses. A lack of information on AR gene expression in leukocytes limits our... more
The α- and β-adrenergic receptors (ARs) bind the stress hormones epinephrine (E), norepinephrine (NE), and dopamine and activate diverse physiological responses. A lack of information on AR gene expression in leukocytes limits our understanding of how stress alters immune function. Quantitative analyses of AR gene expression was completed for bovine leukocytes. Individual leukocyte lineages and subpopulations within lineages were isolated with high-speed cell sorting to facilitate a targeted analysis of AR gene expression. These analyses confirmed all 9 AR genes were expressed in bovine leukocytes with marked differences in AR gene expression when comparing among leukocyte lineages. Furthermore, separation of polymorphonuclear cells into neutrophils and eosinophils revealed these key innate immune cells also differ significantly in AR gene expression. This study provides the first comprehensive survey of AR gene expression in immune cells of any mammalian species and provides insight into conflicting reports that stress can either activate or suppress immune function.
Research Interests:
Inter-individual variance in host immune responses following vaccination can result in failure to develop protective immunity leaving individuals at risk for infection in addition to compromising herd immunity. While developing more... more
Inter-individual variance in host immune responses following vaccination can result in failure to develop protective immunity leaving individuals at risk for infection in addition to compromising herd immunity. While developing more efficacious vaccines is one strategy to mitigate this problem, predicting vaccine responsiveness prior to vaccination could inform which individuals require adjunct disease management strategies. To identify biomarkers of vaccine responsiveness, a cohort of pigs (n = 120) were vaccinated and pigs representing the high (n = 6; 90th percentile) and low (n = 6; 10th percentile) responders based on vaccine-specific antibody responses following vaccination were further analyzed. Kinase-mediated phosphorylation events within peripheral blood mononuclear cells collected prior to vaccination identified 53 differentially phosphorylated peptides when comparing low responders with high responders. Functional enrichment analysis revealed pro-inflammatory cytokine si...
Research Interests:
The mite Varroa destructor is a serious threat to honeybee populations. Selective breeding for Varroa mite tolerance could be accelerated by biomarkers within individual bees that could be applied to evaluate a colony phenotype.... more
The mite Varroa destructor is a serious threat to honeybee populations. Selective breeding for Varroa mite tolerance could be accelerated by biomarkers within individual bees that could be applied to evaluate a colony phenotype. Previously, we demonstrated differences in kinase-mediated signaling between bees from colonies of extreme phenotypes of mite susceptibility. We expand these findings by defining a panel of 19 phosphorylation events that differ significantly between individual pupae from multiple colonies with distinct Varroa mite tolerant phenotypes. The predictive capacity of these biomarkers was evaluated by analyzing uninfested pupae from eight colonies representing a spectrum of mite tolerance. The pool of biomarkers effectively discriminated individual pupae on the basis of colony susceptibility to mite infestation. Kinome analysis of uninfested pupae from mite tolerant colonies highlighted an increased innate immune response capacity. The implication that differences ...
Research Interests:
Dietary interventions to manipulate neonatal gut microbiota have been proposed to generate long-term impacts on hosts. Currently, our understanding of the early gut microbiome of neonatal calves is limited to 16S rRNA gene amplicon based... more
Dietary interventions to manipulate neonatal gut microbiota have been proposed to generate long-term impacts on hosts. Currently, our understanding of the early gut microbiome of neonatal calves is limited to 16S rRNA gene amplicon based microbial profiling, which is a barrier to developing dietary interventions to improve calf gut health. The use of a metagenome sequencing-based approach in the present study revealed high individual animal variation in taxonomic and functional abundance of intestinal microbiome and potential impacts of early microbiome on mucosal immune responses during the preweaning period. During this developmental period, age- and diet-related changes in microbial diversity, richness, density, and the abundance of taxa and functions were observed. A correlation-based approach to further explore the individual animal variation revealed potential enterotypes that can be linked to calf gut health, which may pave the way to developing strategies to manipulate the m...
Research Interests:
Research Interests:
Research Interests:
In the last decade it has become apparent that bacterial deoxyribonucleic acid (DNA) is recognized as a &amp;amp;quot;danger signal&amp;amp;quot; by the mammalian immune system. To investigate this interaction, sheep were injected... more
In the last decade it has become apparent that bacterial deoxyribonucleic acid (DNA) is recognized as a &amp;amp;quot;danger signal&amp;amp;quot; by the mammalian immune system. To investigate this interaction, sheep were injected intradermally two centimeters distal to the lateral prominence of the fibular head with 400 microg of purified plasmid DNA. Over a 28-day period ultrasound measurements indicated a progressive increase in size of both plasmid and saline (controls) treated popliteal lymph nodes and at Day 30 macroscopic and histological measurements of the lymph nodes were determined. Compared with the contralateral control lymph nodes, plasmid exposed lymph nodes were heavier (2.8 +/- 0.1g vs. 2.0 +/- 0.6 g) and displayed prominent histological changes in the cortex and medulla. Average medullary cord thickness (114.2 +/- 25.2 microm) and the average distance across medullary sinuses (64.4 +/- 2.5 microm) were significantly greater after plasmid exposure relative to contralateral controls (62.7 +/- 14.9 microm and 36.5 +/- 1.0 microm, respectively). Total number of germinal centers (71.4 +/- 17.7) and the total area of germinal centers (4.0 +/- 1.3 mm(2)) within the cortex of popliteal lymph nodes exposed to plasmid were also significantly greater than the controls (40.4 +/- 11.4 and 1.6 +/- 0.5 mm(2), respectively). Our results demonstrate that a single exposure to plasmid DNA has long term effects on regional lymph node weight and morphology.
Research Interests:
Research Interests: Immunology, Immune response, Clinical Trial, Biology, Cell Signaling, and 15 moreInnate immunity, Medicine, Toll like receptor signaling, Infectious Disease, Adaptive Immunity, Animals, CpG islands, DNA vaccines, Mouse Model, Immune system, Biological activity, Species Specificity, Innate Immune System, TLR, and Domestic animal
Research Interests:
A new method of analysis of kinome data takes account of the differences between peptide arrays and DNA microarrays.
Research Interests:
Intestinal Peyer’s patch (PP) regulatory CD21+ B cells (Bregs) suppress TLR9-induced innate immune responses. However, it is not known whether TLR9 activation is regulated in PP Bregs. Here, we investigated the responses of PP Bregs to... more
Intestinal Peyer’s patch (PP) regulatory CD21+ B cells (Bregs) suppress TLR9-induced innate immune responses. However, it is not known whether TLR9 activation is regulated in PP Bregs. Here, we investigated the responses of PP Bregs to stimulation with the TLR9 agonist CpG oligodeoxynucleotides (ODN). We observed that PP CD21+ Bregs express high levels of TLR9 mRNA, but fail to proliferate when stimulated with CpG ODN. Furthermore, unlike CD21+ B cells from blood, PP CD21+ Bregs do not secrete IgM or IL-12 following CpG ODN stimulation. We hypothesized that the unresponsiveness of PP Bregs to CpG stimulation was due to an inability of the TLR9 agonist to activate the TLR9 signaling pathway in these cells. This was confirmed by kinome analysis which demonstrated dynamic patterns of phosphorylation of key TLR adaptor proteins such as IRAK1, TAK1, IKK and NF-ĸB-p65 in CpG-stimulated blood CD21+ B cells, consistent with activation of the TLR9 pathway. In contrast, stimulation of PP CD21...
Research Interests:
Research Interests:
Elevated levels of the enzymes gamma-glutamyltransferase (GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and C-reactive protein (CRP) have been shown to be associated with increased... more
Elevated levels of the enzymes gamma-glutamyltransferase (GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and C-reactive protein (CRP) have been shown to be associated with increased risk of cardiovascular disease (CVD). Objective: To assess cross-sectional relationships between biomarkers GGT, ALT, AST, ALP and CVD in adult Canadian population. The Canadian Health Measures Surveys (CHMSs) are a series of cross-sectional national surveys and collect information on indicators of general health and wellness of Canadians. The CHMS has four components. We used data from the first three components (for Study participants ≥ 20 years) from CHMS cycles 1 through 5. Multivariable logistic regression revealed: immigration status [Odds ratio (OR)(95% Confidence Interval (95% CI)) = 0.67 (0.53–0.85), reference category (RC)-no-immigrant] education [1.38(1.10–1.75), RC- > secondary education]; smoking status [ex-smokers: 1.16(0.89–1.51); current smokers: 1.41(0.98–2.05), RC-non-smoker]; and income [middle income: 0.69(0.43–1.10); high income: 0.49(0.29–0.83); RC-lower income] were significantly associated with CVD prevalence. The relationship of GGT with CVD prevalence changed among age groups and body mass index categories; was different for males and females; and diabetes was an effect modifier in the relationship between AST and CVD prevalence. Socio-economic factors were significantly associated with CVD prevalence.
Research Interests:
Mycobacterium avium subsp. paratuberculosis (MAP) is the causative infectious agent of Johne’s disease (JD), an incurable granulomatous enteritis affecting domestic livestock and other ruminants around the world. Chronic MAP infections... more
Mycobacterium avium subsp. paratuberculosis (MAP) is the causative infectious agent of Johne’s disease (JD), an incurable granulomatous enteritis affecting domestic livestock and other ruminants around the world. Chronic MAP infections usually begin in calves with MAP uptake by Peyer’s patches (PP) located in the jejunum (JE) and ileum (IL). Determining host responses at these intestinal sites can provide a more complete understanding of how MAP manipulates the local microenvironment to support its long-term survival. We selected naturally infected (MAPinf, n=4) and naive (MAPneg, n=3) cows and transcriptionally profiled the JE and IL regions of the small intestine and draining mesenteric lymph nodes (LN). Differentially expressed (DE) genes associated with MAP infection were identified in the IL (585), JE (218), jejunum lymph node (JELN) (205), and ileum lymph node (ILLN) (117). Three DE genes (CD14, LOC616364 and ENSBTAG00000027033) were common to all MAPinf versus MAPneg tissues....
Research Interests:
Additional file 4: Dataset S3. PCIP-seq, ddPCR and validation oligos.
Additional file 1: Figure S1. Clonality pie charts in sheep and cattle. Figure S2. SNP validation by clone specific PCR. Figure S3. Distinguishing between real SNPs and technical artifacts. Figure S4. Hypermutation in BLV proviruses.... more
Additional file 1: Figure S1. Clonality pie charts in sheep and cattle. Figure S2. SNP validation by clone specific PCR. Figure S3. Distinguishing between real SNPs and technical artifacts. Figure S4. Hypermutation in BLV proviruses. Figure S5. Validation of BLV structural variants by clone specific PCR. Figure S6. SNPs and recombination in the HIV-1 cell line U1. Figure S7. Estimation of the efficiency of PCIP-seq. Figure S8. Examples of HIV-1 proviruses from patient 02006. Figure S9. Insertion site of ERV causing cholesterol deficiency in Holstein cattle. Figure S10. Validated BERVK2 identified via PCIP-seq. Figure S11. ERV BTA3_115.3 LTRs match APOB (BTA11_77.9) ERV. Figure S12. Validated enJSRV. Table S1. Comparing PCIP-seq to ligation mediated PCR and Illumina sequencing. Table S2. SNPs identified in each sample. Table S3. BLV structural variants identified by PCIP-seq. Table S4. HIV-1 patients' clinical information. Table S5. BERVK2s identified in cattle by PCIP-seq. Table...
Additional file 2. Bacterial species in URT and relationship between stress and microbial functions and stress and immune responses.
Additional file 1. Microbial profiles, taxonomic composition and functional profiles of URT microbiome.
Temporally DE genes list. Sheet 1. Temporally DE genes in the jejunum. Sheet 2. Temporally DE genes in the ileum. (XLSX 186Â kb)
DAVID function of commonly expressed genes in the jejunum and ileum. (XLSX 15Â kb)
Efficacies of two miticides, Apivar<sup>®</sup> and Thymovar<sup>®</sup>, were evaluated as a fall treatment against <i>V. destructor</i>. The effect of treatment with miticides was further evaluated by... more
Efficacies of two miticides, Apivar<sup>®</sup> and Thymovar<sup>®</sup>, were evaluated as a fall treatment against <i>V. destructor</i>. The effect of treatment with miticides was further evaluated by monitoring both viral load and rate of indoor overwintering survival of colonies of European honey bees (<i>Apis mellifera</i> L.) in the vicinity of Saskatoon, Saskatchewan, Canada. Forty-five colonies were randomly assigned to three treatment groups with 15 hives per group%3A Group 1; 2 strips of Thymovar<sup>®</sup> (thymol); Group 2; 2 strips of Apivar<sup>®</sup> (Amitraz); and Group 3; no treatment (control). Significant decreases in the rates of colony infestation (Mites per hundred bees, MPHB) by <i>V. destructor</i> were observed (<i>p</i> ® in October 2013 when compared to control colonies. Efficacy of Apivar<sup>®</sup> and Thymovar<sup>®</sup> against &l...
Research Interests:
Research Interests:
Background Bovine Leukemia Virus (BLV) is a deltaretrovirus that integrates into B-cells producing a lifelong infection in cattle. Like its close relative Human T-cell leukemia virus-1 (HTLV-1) BLV induces an aggressive leukemia/lymphoma... more
Background Bovine Leukemia Virus (BLV) is a deltaretrovirus that integrates into B-cells producing a lifelong infection in cattle. Like its close relative Human T-cell leukemia virus-1 (HTLV-1) BLV induces an aggressive leukemia/lymphoma in about ~5% of infected individuals. While not a natural host it is possible to infect sheep with BLV and in contrast to cattle, all infected sheep develop tumors at an accelerated rate (~18 months). Historically research into both viruses has primarily focused on their transcripts/proteins. However secondary events are likely to be important as only a subset of infected individuals, following many decades of infection, develop a neoplasm. Recent work in HTLV-1 induced adult T cell leukemia/lymphoma (ATL) identified a large number of somatic changes associated with malignancy. At the current time little is known about the landscape of somatic changes in BLV induced tumors. Methods To examine gross numerical and structural aberrations in BLV induced tumors we assayed 12 bovine tumors on the BovineSNP50 Illumina BeadChip as well as 22 ovine tumors on the OvineSNP50 Illumina BeadChip. The resultant data was examined with penCNV in combination with visual inspection of the Log R ratios and B allele frequencies. Results The tumors from both species showed frequent aneuploidy with the whole or a large part of chromosomes BTA5, BTA10, BTA14 and BTA24 duplicated in >50% of the bovine tumors. In the ovine tumors chromosomes OAR5, OAR7, OAR9 and OAR16 were frequently duplicated. It is interesting to note that BTA14 is orthologous to OAR9 and both are orthologous to HSA8q, a part of the human genome frequently duplicated in ATLs and other leukemias. In addition a number of focal structural variants were observed. In cattle the terminus of BTA16, which includes the CD45 gene and miR-181 was amplified (>4 copies) in three tumors. In sheep, mirroring observations in ATL, the CDKN2A gene was deleted in multiple tumors. Conclusion These preliminary results indicate that tumors induced by HTLV-1 and BLV display somatic structural changes that impinge on overlapping sets of genes. Secondarily, it appears that in the case of BLV despite the much shorter incubation periods in sheep, the resultant tumors in both the natural and the experimental host display evidence of substantial genome instability.Peer reviewe
Research Interests:
The integration of a viral genome into the host genome has a major impact on the trajectory of the infected cell. Integration location and variation within the associated viral genome can influence both clonal expansion and persistence of... more
The integration of a viral genome into the host genome has a major impact on the trajectory of the infected cell. Integration location and variation within the associated viral genome can influence both clonal expansion and persistence of infected cells. Methods based on short-read sequencing can identify viral insertion sites, but the sequence of the viral genomes within remains unobserved. We develop PCIP-seq, a method that leverages long reads to identify insertion sites and sequence their associated viral genome. We apply the technique to exogenous retroviruses HTLV-1, BLV, and HIV-1, endogenous retroviruses, and human papillomavirus.
Research Interests:
Research Interests:
The lack of bovine leukemia virus (BLV) expression is a consistent finding in freshly isolated ovine tumor cells and in the B-cell lines derived from these tumors. In order to gain further insight into the mechanisms of BLV silencing in... more
The lack of bovine leukemia virus (BLV) expression is a consistent finding in freshly isolated ovine tumor cells and in the B-cell lines derived from these tumors. In order to gain further insight into the mechanisms of BLV silencing in these tumors, we have used the YR2 B-cell line, which was derived from the leukemic cells of a BLV-infected sheep. This cell line contains a single, monoclonally integrated, silent provirus, which cannot be reactivated either by stimulation in vitro or by in vivo injection of the tumor cells or cloned proviral DNA in sheep. Sequence analysis of the tax gene from the YR2 cell line identified two G-to-A transitions (G 7924 to A 7924 and G 8149 to A 8149 ) that result in E-to-K amino acid changes at positions 228 and 303 in the Tax protein. Following retroviral vector-mediated transfer of a wild-type tax gene into YR2 cells, we showed that BLV mRNA, viral proteins, and virions were produced, demonstrating that the cellular factors required for virus exp...
Research Interests: Biology, Virology, Medicine, Sequence Analysis, Cell Culture, and 15 moreBiological Sciences, Cell line, Sheep, Animals, Rats, Genetic Recombination, Homologous Recombination, B Lymphocytes, Base Sequence, Amino Acid Substitution Rates, Molecular Sequence Data, virus integration, Bovine Leukemia Virus, Medical and Health Sciences, and B cell
Retroviral infections create a large population of cells, each defined by a unique proviral insertion site. Methods based on short-read high throughput sequencing can identify thousands of insertion sites, but the proviruses within remain... more
Retroviral infections create a large population of cells, each defined by a unique proviral insertion site. Methods based on short-read high throughput sequencing can identify thousands of insertion sites, but the proviruses within remain unobserved. We have developed Pooled CRISPR Inverse PCR sequencing (PCIP-seq), a method that leverages long reads on the Oxford Nanopore MinION platform to sequence the insertion site and its associated provirus. We have applied the technique to three exogenous retroviruses, HTLV-1, HIV-1 and BLV, as well as endogenous retroviruses in both cattle and sheep. The long reads of PCIP-seq improved the accuracy of insertion site identification in repetitive regions of the genome. The high efficiency of the method facilitated the identification of tens of thousands of insertion sites in a single sample. We observed thousands of SNPs and dozens of structural variants within proviruses and uncovered evidence of viral hypermutation, recombination and recurre...
Research Interests:
Research Interests: Dairy Science, Control, Biology, Agriculture, Diarrhea, and 15 moreInfection and immunity, Dairy Microbiology, Disease Control, Dairy, Diarrhoeal disease, Goats, Cattle, Beef Cattle, Dairy Cattle, Diarrhoeal Diseases, Diarrhoea, Dairy Goats, Enteric Pathogens, Dairy Goat, and Enteric and diarrheal diseases
Research Interests:
Research Interests:
Research Interests:
The Toll-like receptors (TLRs) are a family of pathogen recognition receptors that alert the host to the presence of microbial challenge. Each TLR responds to a specific microbial associated ligand. For example, TLR4 is activated by... more
The Toll-like receptors (TLRs) are a family of pathogen recognition receptors that alert the host to the presence of microbial challenge. Each TLR responds to a specific microbial associated ligand. For example, TLR4 is activated by lipopolysaccharide (LPS), whereas TLR9 responds to microbial DNA (CpGs). In this report signal transduction responses of bovine monocytes to stimulation with LPS and CpG are described through a bovine-specific peptide array. In addition to confirming activation of the defined TLR pathway in bovine cells, unique phosphorylation events not previously attributed to TLR signaling are described and validated. For example, array data predicts phosphorylation of Tyr40 of Etk in response to LPS, but not CpG, stimulation as well as the activation of oxidative burst in CpG, but not LPS. This investigation confirms interspecies conservation of the TLR pathway in bovine as well as providing insight into the complexity and mechanisms of TLR signaling.
Research Interests: Biology, Cell Biology, Medicine, Signal Transduction, Toll like receptor signaling, and 15 moreToll Like Receptors, Lipopolysaccharide, Protein Kinases, Animals, Phosphorylation, Cattle, Lipopolysaccharides, Monocytes, Receptors, Receptor, Kinome, Superoxides, Respiratory Burst, Biochemistry and cell biology, and TLR
Background Recently, questions have been raised regarding the ability of animal models to recapitulate human disease at the molecular level. It has also been demonstrated that cellular kinases, individually or as a collective unit (the... more
Background Recently, questions have been raised regarding the ability of animal models to recapitulate human disease at the molecular level. It has also been demonstrated that cellular kinases, individually or as a collective unit (the kinome), play critical roles in regulating complex biology. Despite the intimate relationship between kinases and health, little is known about the variability, consistency and stability of kinome profiles across species and individuals. Results As a preliminary investigation of the existence of species- and individual-specific kinotypes (kinome signatures), peptide arrays were employed for the analysis of peripheral blood mononuclear cells collected weekly from human and porcine subjects (n = 6) over a one month period. The data revealed strong evidence for species-specific signalling profiles. Both humans and pigs also exhibited evidence for individual-specific kinome profiles that were independent of natural changes in blood cell populations. Concl...
Research Interests:
Secondary bacterial respiratory infections are a major cause of mortality in fall-weaned feedlot calves, and epidemiological studies implicate a variety of stressors as significant contributing factors. Experimental studies have... more
Secondary bacterial respiratory infections are a major cause of mortality in fall-weaned feedlot calves, and epidemiological studies implicate a variety of stressors as significant contributing factors. Experimental studies have identified stressors that may compromise pulmonary defense mechanisms but there is no evidence that these functional changes alter respiratory disease outcome. We used a model of combined viral and bacterial respiratory disease to determine if nutritional and psychological stressors (abrupt weaning; AW) altered respiratory disease mortality. Mortality was doubled in AW calves challenged with Mannheimia haemolytica four days after a primary bovine herpesvirus-1 (BHV-1) respiratory infection, when compared to calves adapted to weaning (pre-conditioned; PC) for two weeks prior to respiratory challenge. Reduced survival time and decreased lung pathology in the AW group suggested death was due to an acute systemic reaction. Viral shedding did not differ significa...