• Title/Summary/Keyword: Transmissible spongiform encephalopathy (TSE)

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Identification of Single Nucleotide Polymorphisms in PRNP Gene of Korean Native Goats

  • Hoque, Md. Rashedul;Yu, Seong-Lan;Yeon, Seong-Heum;Lee, Jun-Heon
    • Journal of Animal Science and Technology
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    • v.51 no.6
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    • pp.453-458
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    • 2009
  • Prion protein (PRNP) is known to be a causative protein for transmissible spongiform encephalopathy (TSE), a disease occurring in human and animals. Previous results indicate that the genetic variability can affect the resistance and susceptibility of goat scrapie and can give the guideline for reducing the risk of this disease. Until now, 35 single nucleotide polymorphisms (SNPs) were identified in goat PRNP gene from many countries such as Great Britain, Italy, United States of America and Asian countries etc. In this study, SNPs in PRNP gene have been investigated to research the PRNP variations and their possible TSE risks in 60 Korean native goats. Based on the sequencing results, we identified four SNPs and three of those polymorphisms (G126A, C414T and C718T) were synonymous and the A428G polymorphism was non-synonymous which changes the amino acid histidine to arginine. Previously, all of these four SNPs were identified in Asian native goats. Specifically, five polymorphisms were identified in Asian native goats and two of them (G126A and C414T) were silent mutations, and the other SNPs (T304G, A428G and T718C) caused amino acid changes (W102G, H143R and S240P). Comparing with SNP results from other breeds, this study is an initial step to understand resistance and susceptibility of this disease in Korean native goats.

The current status and control measures of BSE in the worldwide (국내, 외 광우병의 발생 현황과 대응 방안)

  • Yoo, Han-Sang
    • 한국환경농학회:학술대회논문집
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    • 2009.07a
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    • pp.273-282
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    • 2009
  • The transmissible spongiform encephalopathies (TSEs) disease group are fatal neurodegenerative disorders affecting a wide range of hosts. The group includes kuru and Creutzfeldt-Jakob disease (CJD) in humans, scrapie in sheep and goats and Bovine spongiform encephalopathy (BSE) in cattle. The exact nature of the infectious agent involved in the transmission of these diseases remains controversial. However, a central event in their pathogenesis is the accumulation in infected tissues of an abnormal form of a host-encoded protein, the prion protein (PrP). Whereas the normal cellular protein is fully sensitive to protease ($PrP^{sen}$), the disease-associated prion protein ($PrP^d$) is only partly degraded ($PrP^{res}$), its amino-terminal end being removed. BSE was first reported in the mid-80s in the UK. Ten years later, a new form of human prion disease, variant CJD (vCJD) developed in the wake of the BSE epidemic, and there is now strong scientific evidence that vCJD was initiated by the exposure of humans to BSE-infected tissues, thus indicating a zoonotic disease. However, the ban on the feeding of animal-derived proteins to ruminants, and the apparent lack of vertical transmission of BSE, have led to a decline in the incidence of the disease within cattle herd and therefore, an assumed decreased risk for human contacting vCJD. The origin of the original case(s) of BSE still remains an enigma even though three hypotheses have been raised. Hypotheses are i) sheep- or goat-derived scrapie-infected tissues included in meat and bone meal fed to cattle, ii) a previously undetected sporadic or genetic bovine TSE contaminating cattle feed or iii) originating from a human TSE through animal feed contaminated with human remains. A host cellular membrane protein ($PrP^C$), which is abundant in central nervous system tissue, appear to be conformationally altered in the diseased host into a prion protein ($PrP^{Sc}$). This $PrP^{Sc}$ is detergent insoluble and partially protease-resistant ($PrP^{res}$). The term $PrP^{res}$ is normally used to describe the protein detected after protease treatment, in techniques such as Western immunoblotting, and enzyme-linked immunosorbant assay using fresh/frozen tissue. Immunohistochemistry may performed with formalin-fixed tissues. Also, clinical signs of the BSE are one of the major diagnostic indicators. Recently, atypical forms (known as H- and L-type) of BSE have appeared in several European countries, Japan, Canada and the United States. An unusual case was also reported in a miniature zebu. The atypical BSE fall into two groups based on the relative molecular mass (Mm) of the unglycosylated $PrP^{res}$ band relative to that of classical BSE, one of the higher Mm (H-type) and the other lower (L-type). Both types have been detected worldwide as rare cases in older animals, at a low prevalence consistent with the possibility of sporadic forms of prion diseases in cattle. This raises the unwelcome possibility that vCJD could increase in the human population. Now, active surveillance program against BSE is going on in Korea. In regional veterinary service lab, ELISA is applied to screen the BSE in slaughter and confirmatory tests by Western immunoblotting and immunohistochemisty are carried out if there are positive or suspect in the screening test. Also, the ruminant feed ban is rigorously enforced. Removal of specified risk materials such as brain and spinal cord from cattle is mandatory process at slaughter to prevent the infected material from entering the human food chain.

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