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Simple Summary: Bovine tuberculosis is caused by Mycobacterium bovis, which causes tuberculosis in humans and animals. Diagnosis of bovine tuberculosis has relied on examination of immune responses to M. bovis; however, using these methods, disease detection during the earliest phases of infection has been difficult, allowing a window for cattle-to-cattle transmission to occur within a herd. Alternative means of diagnosis could include methods to detect M. bovis or M. bovis DNA in bodily fluids such as nasal secretions, saliva, or blood rather than the animal's response to infection. DNA-from M. bovis was detected in nasal swabs and saliva from a small number of experimentally infected calves during the first 8 weeks after experimental infection. Although DNA from M. bovis could be detected, no culturable M. bovis was recovered from nasal swabs or saliva. Moreover, M. bovis DNA was not found in blood samples collected weekly. Successful infection of all calves was demonstrated using an interferon gamma release assay. Identification of infected animals through the detection of M. bovis will require the use of alternative samples or alternative assays. Bovine tuberculosis is caused by Mycobacterium bovis, a member of the M. tuberculosis complex of mycobacterial species that cause tuberculosis in humans and animals. Diagnosis of bovine tuberculosis has relied on examinations of cell-mediated immune responses to M. bovis proteins using tuberculin skin testing and/or interferon gamma release assays. Even when using these methods, disease detection during the earliest phases of infection has been difficult, allowing a window for cattle-to-cattle transmission to occur within a herd. Alternative means of diagnosis could include methods to detect M. bovis or M. bovis DNA in bodily fluids such as nasal secretions, saliva, or blood. During the first 8 weeks after experimental aerosol infection of 18 calves, M. bovis DNA was detected in nasal swabs from a small number of calves 5, 6, and 8 weeks after infection and in samples of saliva at 1, 7, and 8 weeks after infection. However, at no time could culturable M. bovis be recovered from nasal swabs or saliva. M. bovis DNA was not found in blood samples collected weekly and examined by real-time PCR. Interferon gamma release assays demonstrated successful infection of all calves, while examination of humoral responses using a commercial ELISA identified a low number of infected animals at weeks 4–8 after infection. Examination of disease severity through gross lesion scoring did not correlate with shedding in nasal secretions or saliva, and calves with positive antibody ELISA results did not have more severe disease than other calves. [ABSTRACT FROM AUTHOR]

N-acetylquinovosamine (2-acetamido-2,6-di-deoxy--glucose, QuiNAc) is a relatively rare amino sugar residue found in glycans of few pathogenic gram-negative bacteria where it can play a role in infection. However, little is known about QuiNAc-related polysaccharides in gram-positive bacteria. In a routine screen for bacillus glycan grown at defined medium, it was surprising to identify a QuiNAc residue in polysaccharides isolated from this gram-positive bacterium. To gain insight into the biosynthesis of these glycans, we report the identification of an operon in Bacillus cereus ATCC 14579 that contains two genes encoding activities not previously described in gram-positive bacteria. One gene encodes a UDP-N-acetylglucosamine C4,6-dehydratase, (abbreviated Pdeg) that converts UDP-GlcNAc to UDP-4-keto-4,6--deoxy-GlcNAc (UDP-2-acetamido-2,6-dideoxy-α--xylo-4-hexulose); and the second encodes a UDP-4-reductase (abbr. Preq) that converts UDP-4-keto-4,6--deoxy-GlcNAc to UDP-N-acetyl-quinovosamine in the presence of NADPH. Biochemical studies established that the sequential Pdeg and Preq reaction product is UDP--QuiNAc as determined by mass spectrometry and one- and two-dimensional NMR experiments. Also, unambiguous evidence for the conversions of the dehydratase product, UDP-α--4-keto-4,6-deoxy-GlcNAc, to UDP-α--QuiNAc was obtained using real-time 1H-NMR spectroscopy and mass spectrometry. The two genes overlap by 4 nucleotides and similar operon organization and identical gene sequences were also identified in a few other Bacillus species suggesting they may have similar roles in the lifecycle of this class of bacteria important to human health. Our results provide new information about the ability of Bacilli to form UDP-QuiNAc and will provide insight to evaluate their role in the biology of Bacillus. [ABSTRACT FROM AUTHOR]

Background: The Rocky Mountain elk (Cervus elaphus nelsoni) prion protein gene (PRNP) is polymorphic at codon 132, with leucine (L132) and methionine (M132) allelic variants present in the population. In elk experimentally inoculated with the chronic wasting disease (CWD) agent, different incubation periods are associated with PRNP genotype: LL132 elk survive the longest, LM132 elk are intermediate, and MM132 elk the shortest. The purpose of this study was to investigate potential mechanisms underlying variations in incubation period in elk of different prion protein genotypes. Elk calves of three PRNP genotypes (n = 2 MM132, n = 2 LM132, n = 4 LL132) were orally inoculated with brain homogenate from elk clinically affected with CWD. Results: Elk with longer incubation periods accumulated relatively less PrPSc in the brain than elk with shorter incubation periods. PrPSc accumulation in LM132 and MM132 elk was primarily neuropil-associated while glial-associated immunoreactivity was prominent in LL132 elk. The fibril stability of PrPSc from MM132 and LM132 elk were similar to each other and less stable than that from LL132 elk. Real-time quaking induced conversion assays (RT-QuIC) revealed differences in the ability of PrPSc seed from elk of different genotypes to convert recombinant 132 M or 132 L substrate. Conclusions: This study provides further evidence of the importance of PRNP genotype in the pathogenesis of CWD of elk. The longer incubation periods observed in LL132 elk are associated with PrPSc that is more stable and relatively less abundant at the time of clinical disease. The biochemical properties of PrPSc from MM132 and LM132 elk are similar to each other and different to PrPSc from LL132 elk. The shorter incubation periods in MM132 compared to LM132 elk may be the result of genotype-dependent differences in the efficiency of propagation of PrPSc moieties present in the inoculum. A better understanding of the mechanisms by which the polymorphisms at codon 132 in elk PRNP influence disease pathogenesis will help to improve control of CWD in captive and free-ranging elk populations. [ABSTRACT FROM AUTHOR]

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) that is fatal to free-range and captive cervids. CWD has been reported in the United States, Canada, South Korea, Norway, Finland, and Sweden, and the case numbers in both wild and farmed cervids are increasing rapidly. Studies indicate that lateral transmission of cervids likely occurs through the shedding of infectious prions in saliva, feces, urine, and blood into the environment. Therefore, the detection of CWD early in the incubation time is advantageous for disease management. In this study, we adapt real-time quacking-induced conversion (RT-QuIC) assays to detect the seeding activity of CWD prions in feces samples from clinical and preclinical white-tailed deer. By optimizing reaction conditions for temperature as well as the salt and salt concentration, prion seeding activity from both clinical and preclinical animals were detected by RT-QuIC. More specifically, all fecal samples collected from 6 to 30 months post inoculation showed seeding activity under the conditions of study. The combination of a highly sensitive detection tool paired with a sample type that may be collected non-invasively allows a useful tool to support CWD surveillance in wild and captive cervids., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Hwang, Greenlee and Nicholson.)