Project description:Bovine paratuberculosis is an endemic disease caused by Mycobacterium avium subspecies paratuberculosis (Map). Map is mainly transmitted between herds through movement of infected but undetected animals. Our objective was to investigate the effect of observed herd characteristics on Map spread on a national scale in Ireland. Herd characteristics included herd size, number of breeding bulls introduced, number of animals purchased and sold, and number of herds the focal herd purchases from and sells to. We used these characteristics to classify herds in accordance with their probability of becoming infected and of spreading infection to other herds. A stochastic individual-based model was used to represent herd demography and Map infection dynamics of each dairy cattle herd in Ireland. Data on herd size and composition, as well as birth, death, and culling events were used to characterize herd demography. Herds were connected with each other through observed animal trade movements. Data consisted of 13 353 herds, with 4 494 768 dairy female animals, and 72 991 breeding bulls. We showed that the probability of an infected animal being introduced into the herd increases both with an increasing number of animals that enter a herd via trade and number of herds from which animals are sourced. Herds that both buy and sell a lot of animals pose the highest infection risk to other herds and could therefore play an important role in Map spread between herds.
Project description:In this study, samples of 16 dairy cows from a MAP infected farm were used. Serum, milk and fecal samples were collected. Categorizing these cows into two groups based on their MAP infection status different standard methods for detection MAP were applied. Healthy controls showed no positive results in enzyme-linked immunosorbent assay (ELISA) with serum and milk samples (cattletype MAP Ab, Qiagen, Hilden, Germany; In-direct, IDVet, Grabels, France) and after cultivation of fecal samples on commercial Her-rold´s Egg Yolk Agars (HEYM agar, Becton Dickinson, Heidelberg, Germany) for 12 weeks. Cows with positive results were grouped into MAP infected cows. Specifically, for mass spectrometry analysis serum of seven MAP infected cows and seven healthy controls were used. All animals were from the same farm and were kept under the same environmental conditions. For additional mass spectrometry analysis with a further control group sam-ples of 21 dairy cows from an uninfected farm were examined. All cattle from this farm showed negative results in ELISA with serum and milk samples. Additionally, there was never a positive result in regularly tested fecal samples and sock swab samples of this farm. For verification of differential CTSS expression in Western blot analysis five dairy cows from another infected farm were consultedincluded. MAP status of these cows was analyzed by cultivation of fecal samples on HEYM agar for 12 weeks and ELISA with se-rum samples. In detail, two cattle were categorized into healthy controls and three cattle into MAP infected cows. Withdrawal of bovine venous whole blood and experi-mental protocols were approved by the local authority, Government of Upper Bavaria, permit no. ROB-55.2-2532.Vet_03-17-106.
Project description:BackgroundOur laboratories have previously reported on the experimental infection of cattle with Mycobacterium avium subsp paratuberculosis (M. paratuberculosis) using an intratonsillar infection model. In addition, we have recently developed a partial protein array representing 92 M. paratuberculosis coding sequences. These combined tools have enabled a unique look at the temporal analysis of M. paratuberculosis antigens within the native host. The primary objective of this study was to identify M. paratuberculosis antigens detected by cattle early during infection. A secondary objective was to evaluate the humoral immune response in cattle during the initial year of infection.ResultsSera from two experimentally infected cattle, taken pre-inoculation and at day 70, 194 and 321 post infection, identified dynamic antibody reactivity among antigens with some showing an increased response over time and others showing declining levels of reactivity over the same time period. A M. paratuberculosis specific protein, encoded by MAP0862, was strongly detected initially, but the antibody response became weaker with time. The most reactive protein was a putative surface antigen encoded by MAP1087. A second protein, MAP1204, implicated in virulence, was also strongly detected by day 70 in both cattle. Subsequent experiments showed that these two proteins were detected with sera from 5 of 9 naturally infected cattle in the subclinical stage of Johne's disease.ConclusionCollectively these results demonstrate that M. paratuberculosis proteins are detected by sera from experimentally infected cattle as early as 70 days after exposure. These data further suggest at least two antigens may be useful in the early diagnosis of M. paratuberculosis infections. Finally, the construction and use of a protein array in this pilot study has led to a novel approach for discovery of M. paratuberculosis antigens.
Project description:BackgroundAntibiotic therapy targeting chronic mycobacterial disease is often ineffective due to problems with the emergence of drug resistance and non-replicating persistent intracellular antibiotic resistant phenotypes. Strategies which include agents able to enhance host cell killing mechanisms could represent an alternative to conventional methods with the potential for host clearance if active against dormant phenotypes. Investigations of agents with potential activity against non-replicating mycobacteria however are restricted due to a need for assays that can assess bacterial viability without having to culture.ResultsThis study describes the development and use of a pre16S ribosomal gene RNA/DNA ratio viability assay which is independent of the need for culture, supported by a novel thin layer accelerated mycobacterial colony forming method for determining viability and culturability of MAP in intracellular environments. We describe the use of these tools to demonstrate intracellular killing activity of a novel rhodanine agent (D157070) against the intracellular pathogen Mycobacterium avium subspecies paratuberculosis (MAP) and show that the culturability of MAP decreases relative to its viability on intracellular entry suggesting the induction of a non-culturable phenotype. We further demonstrate that D157070, although having no direct activity against the culturability of extracellular MAP, can bind to cultured MAP cells and has significant influence on the MAP transcriptome, particularly with respect of delta(L )associated genes. D157070 is shown to be taken up by bovine and human cells and able to enhance host cell killing, as measured by significant decreases in both culturability and viability of intracellular MAP.ConclusionsThis work suggests that pre16srRNA gene ratios represent a viable method for studying MAP viability. In addition, the rhodanine agent D157070 tested is non-toxic and enhances cell killing activity against both growing and latent MAP phenotypes.
Project description:Infection with Mycobacterium avium subspecies paratuberculosis (MAP) is complex, but little is known about the role that natural killer (NK) cells play. In the present study, four bovine NK-lysin peptides were synthesized to evaluate their bactericidal activity against MAP. The results demonstrated that bNK-lysin peptides were directly bactericidal against MAP, with bNK1 and bNK2A being more potent than bNK2B and bNK2C. Mechanistically, transmission electron microscopy revealed that the incubation of MAP with bNK2A resulted in extensive damage to cell membranes and cytosolic content leakage. Furthermore, the addition of bNK2A linked with a cell-penetrating peptide resulted in increased MAP killing in a macrophage model.
Project description:Johne's disease is a chronic infection of the small intestine caused by Mycobacterium avium subspecies paratuberculosis (MAP), an intracellular bacterium. The events of pathogen survival within the host cell(s), chronic inflammation and the progression from asymptomatic subclinical stage to an advanced clinical stage of infection, are poorly understood. This study examines gene expression in the ileocecal valve (ICV) of Holstein dairy cows at different stages of MAP infection. The ICV is known to be a primary site of MAP colonization and provides an ideal location to identify genes that are relevant to the progression of this disease. RNA was prepared from ICV tissues and RNA-Seq was used to compare gene transcription between clinical, subclinical, and uninfected control animals. Interpretation of the gene expression data was performed using pathway analysis and gene ontology categories containing multiple differentially expressed genes. Results demonstrated that many of the pathways that had strong differential gene expression between uninfected control and clinical cows were related to the immune system, such as the T- and B-cell receptor signaling, apoptosis, NOD-like receptor signaling, and leukocyte transendothelial migration pathways. In contrast, the comparison of gene transcription between control and subclinical cows identified pathways that were primarily involved in metabolism. The results from the comparison between clinical and subclinical animals indicate recruitment of neutrophils, up regulation of lysosomal peptidases, increase in immune cell transendothelial migration, and modifications of the extracelluar matrix. This study provides important insight into how cattle respond to a natural MAP infection at the gene transcription level within a key target tissue for infection.
Project description:We describe here the complete genome sequence of a common clone of Mycobacterium avium subspecies paratuberculosis (Map) strain K-10, the causative agent of Johne's disease in cattle and other ruminants. The K-10 genome is a single circular chromosome of 4,829,781 base pairs and encodes 4,350 predicted ORFs, 45 tRNAs, and one rRNA operon. In silico analysis identified >3,000 genes with homologs to the human pathogen, M. tuberculosis (Mtb), and 161 unique genomic regions that encode 39 previously unknown Map genes. Analysis of nucleotide substitution rates with Mtb homologs suggest overall strong selection for a vast majority of these shared mycobacterial genes, with only 68 ORFs with a synonymous to nonsynonymous substitution ratio of >2. Comparative sequence analysis reveals several noteworthy features of the K-10 genome including: a relative paucity of the PE/PPE family of sequences that are implicated as virulence factors and known to be immunostimulatory during Mtb infection; truncation in the EntE domain of a salicyl-AMP ligase (MbtA), the first gene in the mycobactin biosynthesis gene cluster, providing a possible explanation for mycobactin dependence of Map; and Map-specific sequences that are likely to serve as potential targets for sensitive and specific molecular and immunologic diagnostic tests. Taken together, the availability of the complete genome sequence offers a foundation for the study of the genetic basis for virulence and physiology in Map and enables the development of new generations of diagnostic tests for bovine Johne's disease.
Project description:BackgroundInfection of cattle with Mycobacterium avium subspecies paratuberculosis (M. ap) causes severe economic losses to the dairy industry in the USA and worldwide. In an effort to better examine diversity among M. ap strains, we used optical mapping to profile genomic variations between strains of M. ap K-10 (sequenced strain) and M. ap ATCC 19698 (type strain).ResultsThe assembled physical restriction map of M. ap ATCC 19698 showed a genome size of 4,839 kb compared to the sequenced K-10 genome of 4,830 kb. Interestingly, alignment of the optical map of the M. ap ATCC 19698 genome to the complete M. ap K-10 genome sequence revealed a 648-kb inversion around the origin of replication. However, Southern blotting, PCR amplification and sequencing analyses of the inverted region revealed that the genome of M. ap K-10 differs from the published sequence in the region starting from 4,197,080 bp to 11,150 bp, spanning the origin of replication. Additionally, two new copies of the coding sequences > 99.8% were identified, identical to the MAP0849c and MAP0850c genes located immediately downstream of the MAP3758c gene.ConclusionThe optical map of M. ap ATCC 19698 clearly indicated the miss-assembly of the sequenced genome of M. ap K-10. Moreover, it identified 2 new genes in M. ap K-10 genome. This analysis strongly advocates for the utility of physical mapping protocols to complement genome sequencing projects.
Project description:Mycobacterium avium subsp. paratuberculosis (MAP) causes a chronic inflammatory intestinal disease, called Johne's disease (JD) in many ruminants. In the dairy industry, JD is responsible for significant economic losses due to decreased milk production and premature culling of infected animals. Test-and-cull strategy in conjunction with risk management is currently recommended for JD control in dairy herds. However, current diagnostic tests are labor-intensive, time-consuming, and/or too difficult to operate on site. In this study, we developed a new method for the detection of anti-M. paratuberculosis antibodies from sera of M. paratuberculosis-infected animals. M. paratuberculosis antigen-coated magnetic beads were sequentially reacted with bovine serum followed by a horseradish peroxidase (HRP)-labeled secondary antibody. The reaction of HRP with its substrate was then quantitatively measured electrochemically using a redox-active probe, ferrocyanide. After optimization of electrochemical conditions and concentration of the redox-active probe, we showed that the new electrochemical detection method could distinguish samples of M. paratuberculosis-infected cattle from those of uninfected cattle with greater separation between the two groups of samples when compared with a conventional colorimetric testing method. Since electrochemical detection can be conducted with an inexpensive, battery-operated portable device, this new method may form a basis for the development of an on-site diagnostic system for JD.
Project description:Mycobacterium avium subspecies paratuberculosis (MAP) causes paratuberculosis (PTB), which is a granulomatous enteritis in ruminants that threatens the dairy industry's healthy development and public health safety worldwide. Because the commercial inactivated vaccines are not completely protective and interfere with bovine tuberculosis diagnostics, we tested four fusion proteins, namely 66NC, 66CN, 90NC, and 90CN, which were constructed with MAP3527, Ag85B, and Hsp70 of MAP in different tandem combinations. Notably, 66NC, which encodes a 66 kDa fusion protein that combines in linear order MAP3527N40-232, Ag85B41-330, and MAP3527C231-361, induced a powerful and specific IFN-γ response. Immunization of C57BL/6 mice with the 66NC fusion protein formulated in Montanide ISA 61 VG adjuvant generated robust Th1, Th2, and Th17 type immune responses and strong antibody responses. The 66NC vaccine protected C57BL/6 mice against virulent MAP K-10 infection. This resulted in a reduction of bacterial load and improvement of pathological damage in the liver and intestine, in addition to a reduction of body weight loss; significantly better protection than the reported 74 F vaccine was also induced. Furthermore, vaccine efficacy correlated with the levels of IFN-γ-, TNF-α-, and IL-17A-secreting antigen-specific CD4+ and CD8+ T lymphocytes as well as with serum IFN-γ and TNF-α levels after vaccination. These results demonstrate that recombinant protein 66NC is an efficient candidate for further development into a protective vaccine in terms of inducing specific protection against MAP.