Publications by authors named "Junsun Park"

While a live-attenuated Yellow fever (YF) vaccine is known to elicit durable immunity, antibody titers may wane after vaccination. This study evaluated the long-term immunity after vaccination against YF among individuals who reside in Korea and received vaccination with YF virus-17D prior to international travel. Serum was collected between December 2018 and December 2019 at the National Medical Center, Republic of Korea from YF vaccine recipients who were vaccinated more than five years prior to sample collection.

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  • Natural Monkeypox virus infection results in higher levels of neutralizing antibodies compared to Jynneos vaccination.
  • Both groups experience similar rates of antibody decline after 6 months.
  • People who received the Jynneos vaccine and had previous smallpox vaccinations show antibody levels similar to those who recovered from mpox.
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  • A 23-year-old male with advanced HIV-1 developed serious monkeypox symptoms, including painful anal ulcers and a perirectal abscess that needed surgical intervention.
  • The abscess was particularly tough to diagnose because it didn't have typical fluid features on imaging.
  • This case illustrates the challenges and severity of monkeypox in individuals with weakened immune systems.
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Background: A global mpox outbreak occurred in 2022, and a domestic outbreak started in South Korea in April 2023. This study aimed to evaluate the clinical characteristics, viral shedding, and immune response of mpox in South Korea.

Methods: Patients hospitalized with mpox in the National Medical Center between September 2022 and June 2023 were included in this study.

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  • - The study focused on analyzing the genomes of monkeypox virus isolates from patients in the Republic of Korea to understand how the virus spreads and evolves over time.
  • - Eight monkeypox virus isolates were classified into Clade IIb, with notable lineages identified including B.1.1, A.2.1, and B.1.3, with B.1.3 being prevalent among isolates from 2023.
  • - The findings suggest that the unique genetic characteristics of these Far East isolates indicate a possible start of local transmission of the B.1.3 lineage in early 2023, particularly among six patients with no recent travel history.
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Formate dehydrogenase (FDH) is critical for the conversion between formate and carbon dioxide. Despite its importance, the structural complexity of FDH and difficulties in the production of the enzyme have made elucidating its unique physicochemical properties challenging. Here, we purified recombinant Methylobacterium extorquens AM1 FDH (MeFDH1) and used cryo-electron microscopy to determine its structure.

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Proper cellular proteostasis, essential for viability, requires a network of chaperones and cochaperones. ATP-dependent chaperonin TRiC/CCT partners with cochaperones prefoldin (PFD) and phosducin-like proteins (PhLPs) to facilitate folding of essential eukaryotic proteins. Using cryoEM and biochemical analyses, we determine the ATP-driven cycle of TRiC-PFD-PhLP2A interaction.

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Accurate folding of proteins in living cells often requires the cooperative support of molecular chaperones. Eukaryotic group II chaperonin Tailless complex polypeptide 1-Ring Complex (TRiC) accomplishes this task by providing a folding chamber for the substrate that is regulated by an Adenosine triphosphate (ATP) hydrolysis-dependent cycle. Once delivered to and recognized by TRiC, the nascent substrate enters the folding chamber and undergoes folding and release in a stepwise manner.

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A 35-year-old man who returned from Germany developed fever, generalized pain, severe anal pain, and generalized skin rash, confirmed to be monkeypox (mpox). While he was previously confirmed to be human immunodeficiency virus infected, antiretroviral therapy ensured his immunocompetence. The mpox-related prodromal symptoms disappeared before isolation, and subsequent several vesicular skin lesions healed after admission.

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Proper cellular proteostasis, essential for viability, requires a network of chaperones and cochaperones. ATP-dependent chaperonin TRiC/CCT partners with cochaperones prefoldin (PFD) and phosducin-like proteins (PhLPs) to facilitate the folding of essential eukaryotic proteins. Using cryoEM and biochemical analyses, we determine the ATP-driven cycle of TRiC-PFD-PhLP2A interaction.

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  • Cryopreservation, a method that involves storing biological materials at extremely low temperatures, is increasingly used for conserving non-orthodox seeds and plants, but there is still a lack of universal protocols for its application.
  • This study developed a detailed droplet-vitrification procedure for cryopreserving chrysanthemum shoot tips, including specific steps for preculture, osmoprotection, and cryoprotection.
  • The successful pilot cryobanking of 154 chrysanthemum accessions resulted in a 74.8% regeneration rate post-cryopreservation, showcasing its potential for long-term conservation of the Asteraceae family germplasm.
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Introduction: Gut microbiome plays a crucial role in maintaining human health and is influenced by food intake, age, and other factors.

Methods: In this study based in Korea, we examined the bacterial taxonomic composition of the gut microbiota in infants (≤ 1 year), toddlers (1-<4 years), and school-aged children (4-13 years) and compared them with those of healthy adults to investigate the microbiota changes in early life and their association with the resistome. We used whole metagenome sequences obtained by Illumina HiSeq sequencing and clinical information of 53 healthy children, and sequence data of 61 adults from our previous study.

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The ATP-dependent ring-shaped chaperonin TRiC/CCT is essential for cellular proteostasis. To uncover why some eukaryotic proteins can only fold with TRiC assistance, we reconstituted the folding of β-tubulin using human prefoldin and TRiC. We find unstructured β-tubulin is delivered by prefoldin to the open TRiC chamber followed by ATP-dependent chamber closure.

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  • Omicron has become the main strain of SARS-CoV-2, making it harder to neutralize despite previous infections or two-dose vaccines.
  • A three-dose mRNA vaccine better boosts neutralizing antibodies and provides longer-lasting protection against various SARS-CoV-2 variants, though levels against Omicron are still low.
  • Individuals who experience an Omicron breakthrough infection after three doses see an increase in neutralizing antibodies and T cell responses, which may enhance immunity against new SARS-CoV-2 variants.
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Background: The immunologic features of children with coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are not clearly delineated. This study was conducted to evaluate SARS-CoV-2-specific antibody responses in children with COVID-19.

Methods: The levels of anti-spike (S) IgG, anti-SARS-CoV-2 IgG, and neutralizing antibody (NAb) were measured during various time points in children <19 years of age with COVID-19 in South Korea from February 2020 to September 2020.

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Concerns about the effectiveness of current vaccines against the rapidly spreading severe acute respiratory syndrome-coronavirus-2 omicron (B.1.1.

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  • The GroEL/GroES chaperonin system plays a crucial role in protein folding by utilizing ATP hydrolysis for conformational changes.
  • Recent research has focused on the less understood football-shaped GroEL:ES complex, specifically its interactions with the substrate ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO).
  • Findings from cryo-EM structures reveal that GroEL can simultaneously accommodate two substrates and that specific hydrophobic residues in GroEL are key to interacting with and folding RuBisCO.
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Cryogenic-electron microscopy (cryo-EM) is the preferred method to determine 3D structures of proteins and to study diverse material systems that intrinsically have radiation or air sensitivity. Current cryo-EM sample preparation methods provide limited control over the sample quality, which limits the efficiency and high throughput of 3D structure analysis. This is partly because it is difficult to control the thickness of the vitreous ice that embeds specimens, in the range of nanoscale, depending on the size and type of materials of interest.

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Objectives: The aim of this study was to investigate the seroprevalence of antibodies against scrub typhus, murine typhus and spotted fever groups among North Korean refugees within 1 year of their arrival in South Korea.

Methods: We recruited North Korean refugees who had settled in South Korea after a short stay in a third country and did not have any health problems. The antibody titer was measured using a commercial indirect fluorescence assay immunoglobulin G antibody kit.

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  • Cases of SARS-CoV-2 reinfection have been documented worldwide, raising questions about the effectiveness of natural immunity from prior infections.
  • A study using ferrets with varying levels of neutralizing antibody (NAb) titres after initial infection showed that those with high NAb titres experienced less viral replication and quicker clearance when reinfected.
  • The findings suggest that low NAb titres are connected to reinfection risk, with limited lung inflammation observed in ferrets with high NAb titres compared to those with low levels.
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  • Positive results from rRT-PCR in recovered COVID-19 patients raise concerns about potential reinfection, but no evidence of reinfection has been documented until now.
  • The study involved whole-genome sequencing of viral RNA from patients who tested positive again after recovering, discovering differences between their initial infections and positive retests.
  • Findings indicated that one patient had a reinfection with a genetically distinct strain, suggesting recovered patients may not have immunity to different variants of SARS-CoV-2.
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The previous outbreaks of SARS-CoV and MERS-CoV have led researchers to study the role of diagnostics in impediment of further spread and transmission. With the recent emergence of the novel SARS-CoV-2, the availability of rapid, sensitive, and reliable diagnostic methods is essential for disease control. Hence, we have developed a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for the specific detection of SARS-CoV-2.

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