• IMMUNE NETWORK
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• v.20 no.5
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• pp.41.1-41.11
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• 2020

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) is a positive-sense single-stranded RNA (+ssRNA) that causes coronavirus disease 2019 (COVID-19). The viral genome encodes twelve genes for viral replication and infection. The third open reading frame is the spike (S) gene that encodes for the spike glycoprotein interacting with specific cell surface receptor - angiotensin converting enzyme 2 (ACE2) - on the host cell membrane. Most recent studies identified a single point mutation in S gene. A single point mutation in S gene leading to an amino acid substitution at codon 614 from an aspartic acid 614 into glycine (D614G) resulted in greater infectivity compared to the wild type SARS-CoV2. We were interested in investigating the mutation region of S gene of SARS-CoV2 from Korean COVID-19 patients. New mutation sites were found in the critical receptor binding domain (RBD) of S gene, which is adjacent to the aforementioned D614G mutation residue. This specific sequence data demonstrated the active progression of SARS-CoV2 by mutations in the RBD of S gene. The sequence information of new mutations is critical to the development of recombinant SARS-CoV2 spike antigens, which may be required to improve and advance the strategy against a wide range of possible SARS-CoV2 mutations.

• Childhood Kidney Diseases
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• v.8 no.2
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• pp.176-185
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• 2004

Purpose: Rapidly progressive glomerulonephritis (RPGN) is a clinicopathologic entity characterized by extensive crescent formation and rapid deterioration of renal function within few months. For better understanding of its clinical course and designing better treatment strategies, a clinicopathological study of childhood RPGN was performed. Methods: The clinical manifestations and pathological findings were reviewed retrospectively in 12 children who were diagnosed as having RPGN by clinical manifestations and renal biopsy during a period from 1991 to 2003. Several clinicopathological parameters were analyzed as prognostic factors. Results: Among a total of 12 patients, 4 were male and 8 were female. The median onset age was 11.5 years(range 5.5-14.6 years), and the median period of follow-up was 25 months(range 7 months-6.6 years). According to the pathological classification, 10 patients (83%) were type II RPGN(immune-complex mediated glomerulonephritis), 2 patients were type III RPGN(pauci-immune glomerulonephritis), and none was type I RPGN(anti-glomerular basement membrane nephritis). All patients were treated with oral steroid in various combinations with methylprednisolone pulse therapy(10 patients, 83%), cyclophosphamide(8 patients, 67%), or plasmapheresis(4 patients, 33%). Clinical outcomes of 12 patients were complete remission in 1(8%), end-stage renal disease in 2(17%), chronic renal insufficiency with persistent proteinuria in 2(17%), and normal renal function with persistent proteinuria in 7(58%) at the last follow-up. Poor prognosis is associated with increased serum creatinine level, severe anemia and younger age at the time of diagnosis. Conclusion: Immune-complex mediated glomerulonephritis is the major cause RPGN in children and most cases showed improvement of renal function with aggressive management. For better understanding of this rare disease, a prospective multicenter study should be done.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.67-73
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• 2005

Photoautotrophic bacteria are promising candidates for the production of poly(3-hydroxybutyrate) (PHB) since they can address the critical problem of substrate costs. In this study, we isolated 25 Tn5-inserted mutants of the Synechocystis sp. PCC 6803 which showed enhanced PHB accumulation compared to the wild-type strain. After 5-days cultivation under nitrogen-limited mixotrophic conditions, the intracellular levels of PHB content in these mutants reached up to $10-30\%$ of dry cell weight (DCW) comparable to $4\%$ of DCW in the wild-type strain. Using the method of inverse PCR, the affected genes of the mutants were mapped on the completely known genome sequence of Synechocystis sp. PCC 6803. As a result, the increased PHB accumulation in 5 mutants were found to be resulted from defects of genes coding for NADH-ubiquinone oxidoreductase, O-succinylbenzoic-CoA ligase, photosystem II PsbT protein or histidine kinase, which are involved in photosystem in thylakoid inner membrane of the cell. The values of $NAD(P)H/NAD(P)^+$ ratio in the cells of these mutants were much higher than that of the wild-type strain as measured by using pulse-amplitude modulated fluorometer, suggesting that PHB synthesis could be enhanced by increasing the level of cellular NAD(P)H which is a limiting substrate for NADPH-dependent acetoacetyl-CoA reductase. From these results, it is likely that NAD(P)H would be a limiting factor for PHB synthesis in Synechocystis sp. PCC 6803.