• Journal of Microbiology and Biotechnology
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• v.23 no.7
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• pp.1015-1022
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• 2013

We recently showed that polylysine, the polymer of lysines, retains anti-prion activity. Although the effectiveness of prion inhibition by polylysine was demonstrated with the regimen tolerated in mice, a determination of quantitative polylysine toxicity is necessary to precisely address the in vivo toxicity level of polylysine. In this communication, we report the results of body weight monitoring and hematologic tests performed in CD-1 mice that received two different tolerable dosages of polylysine for an either 5-day or 4-week period. We found that there was no significant alteration in overall serum chemistry, blood cell count, and body weight gain compared with controls. The only notable quantitative change with statistical significance was the decrease of platelet numbers in mice subchronically administered with polylysine. Our results suggest that polylysine is harmless in mice if administered for a short period, but administrations of polylysine in mice may require considerate attention for safety in future investigations as mice chronically receive tolerable doses of polylysine.

• 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.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.122-126
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• 2010

RAD53 functions as an effector kinase of checkpoint pathways in Saccharomyces cerevisiae, which plays a central role to regulate many downstream cellular processes in response to DNA damage. It also involves in transcriptional activation of various genes including RNR genes which encode the key enzyme required for dNTP synthesis. In this study, we identified CYC8 as a suppressor for the hydroxyurea sensitivity of $rad53{\Delta}$ mutation. $Rad53{\Delta}$ mutant transformed with a multi-copy plasmid containing CYC8 showed increased hydroxyurea resistance. In contrast, TUP1 which forms a complex with CYC8 did not function as a suppressor. In the case of mutations, both $cyc8{\Delta}$ and $tup1{\Delta}$ suppressed hydroxyurea sensitivity of $rad53{\Delta}$. Since CYC8 can propagate as a prion in yeast, overexpression of CYC8 induced misfolding of the normal CYC8 proteins, resulting in dominant cyc8-phenotype. Therefore, it is suggested that CYC8 can act as a multi-copy suppressor due to its prion property. It was observed that the levels of RNR transcription were increased in the yeast strains containing either multi-copies of CYC8 gene or $cyc8{\Delta}$ mutation, suggesting that the increased level of RNR will elevate the intracellular pools of dNTPs, which, in turn, suppress the phenotype of $rad53{\Delta}$ mutation.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.731-734
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• 2011

• The Science & Technology
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• no.1 s.416
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• pp.12-15
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• 2004

국내 7개 대학이 참여한 생명공학 연구팀이 최근 광우병을 유발하는 것으로 알려진 '프리온(Prion) 단백질'을 생체내에서 축적되지 않으면서 정상기능을 하도록 변형된 '프리온 변이단백질'을 과다 발현시킨 수정란을 대리모에 착상시키는 방법으로 '광우병 내성 복제소' 4마리를 생산했다. 국제특허를 출원한 것은 물론이고, 지난해 12월 10일 노무현 대통령, 박호군 과학기술부 장관, 정운찬 서울대 총장 등 150여 명이 참석한 가운데 전체 과정을 시연해 보였다. 세계 5번째로 체세포 복제소를 탄생시켜 우리 나라 생명공학기술 수준을 세계에 알렸던 황우석 서울대 수의과 교수가 이번에 또 팀을 이끌며 일을 저질렀다.

• Journal of Veterinary Clinics
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• v.19 no.2
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• pp.247-249
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• 2002

A 6-month-old female Pekingese was euthanized due to poor progrosis after 1 month history of neurologic signs that include depression, ataxia, urination and defecation difficulty. At necropsy, no significant gross abnormalities were noted Histologically, neuronal vacuolation was noted in the brain, primarily cerebellum and occasionally in the brain stem area. Neuronal necrosis and secondary axonal swelling were also observed. Differential diagnoses were able to rule out other diseases which can induce neuronal vacuolation such as lysosomal storage disease, prion infection, and postvaccinal change.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.417-421
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• 2004

A normal prion protein (PrPc) is converted to a protease resistant isoform (PrPsc) by an apparent self-propagating activity in bovine spongiform encephalopathies (BSE), which is a neurodegenerative disease. The cDNA encoding bovine PrP open reading frame (ORP) in Korean cattle was cloned by polymerase chain reaction (PCR). The cloned cDNA had a length of 795 base pairs which coded for a protein of 264 amino acid residues with a calculated molecular mass of 28.6 kDa. Identities of 90, 90, 79 and 78% on nucleotide and 94, 94, 84, and 84% on amino acid sequence were shown to PrP genes from sheep, goat, human, and mouse, respectively. The cloned DNA was ligated into the pQE30 expression vector and transformed into E. coli M15. The PrP was expressed by induction with isopropyl-$\beta$-D-thiogalactoside (IPTG) and purified on the Ni-NTA affinity column. High specific activities of the recombinant PrP were observed in the fraction of pH 5.8 eluate and showed a molecular mass of-29 kDa on SDS-PAGE and Western blot analysis.

• Journal of the Korean Society of Tobacco Science
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• v.27 no.2
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• pp.212-218
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• 2005

Cigarette smoking has been known to have a few beneficial effects on some neuronal diseases such as Alzheimer's disease(AD), Parkinson's disease(PD) and prion disease by scrapie agent shows many similar properties with AD. In this respect, we investigated what biological effects are exerted by cigarette smoke exposure(CSE) in the brain of mouse infected by 87V scrapie. The scrapie agent was inoculated through stereotaxic microinjection of the homogenates of the scrapie agent infected brain into the intracerebral system in the 1M mice. The inoculation into mice typically exhibits neurochemical, physiological and histopathological characteristics of prion disease: loss of neurotransmitters and induction of astrocytosis and vacuolation in brain as well as reduction of spatial movement and loss of body weight. CSE led to alleviated the loss of body weight and also improved spatial movement of the infected mice. Most interestingly, CSE attenuated astrocytosis and vacuolation caused by scrapie infection in the brain. In addition, decreased levels of dopamine in striatal and hypothalamic regions as well as serotonin level in hippocampus caused by scrapie infection were also attenuated by exposure to cigarette smoke. These findings suggest that cigarette smoke, by its inhibition of astrocytosis and vacuolation followed by its restoration of levels of some neurotransmitters, may partly contribute to suppression in the progress of neurodegeneration caused by scrapie infection.

• 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.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.207-209
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• 2005

Serum is a potential source of bacterial, mycoplasmal and viral contamination, and it has a possibility of the introduction of serum proteins, prion and pyrogens into the final vaccine product. For porcine Rotavirus vaccine production, it is necessary to develop serum free medium which do not cause those problems. A new serum free medium was developed for porcine Rotavirus vaccine based on DMEM, and the performance of developed serum free medium was evaluated in terms of Vero cell growth and Rotavirus vaccine production. The cell density, gown in serum free medium developed, was similar with that in serum supplemented medium. Also, it was higher than that in other commercially available serum free medium. The productivity of Rotavirus vaccine using serum free medium developed and optimum production strategies will be also discussed.