A Seroprevalence Study on Residents in a Senior Care Facility with Breakthrough SARS-CoV-2 Omicron Infection.

The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began spreading rapidly in the community in November 2021, becoming the dominant variant in the Republic of Korea in 2022. Although its pathogenesis in healthy individuals was low, the severity and hospitalization rate was higher in the elderly and immunocompromised patients. We aimed to investigate the immunogenicity in acute and convalescent phases of breakthrough infection by Omicron in elderly individuals. Serological data were assessed by electrochemiluminescence immunoassay, enzyme-linked immunosorbent assay, and plaque-reduction neutralization tests. SARS-CoV-2-specific antibody and immunoglobulin G levels in the acute phase were higher in third dose-vaccinated elderly than in first and second dose-vaccinated patients. The neutralization antibody titer was detected only in third dose-vaccinated patients, and the titer was higher for the Delta than the Omicron variant. In the convalescent phase of Omicron infection, the neutralization antibody titer of vaccinated patients was higher for the Delta than the Omicron variant except in unvaccinated individuals. We demonstrated that the cause of the vulnerability to Omicron variant infection in third dose-vaccinated elderly was due to the low neutralization antibody level against Omicron. A fourth dose of vaccination is required in the elderly to reduce hospitalization and mortality caused by the Omicron variant.

Sustained Vaccination Coverage during the Coronavirus Disease 2019 Epidemic in the Republic of Korea.

Amid the COVID-19 pandemic, vaccination coverage may decline due to limited accessibility to healthcare. We assessed the impact of the COVID-19 pandemic on vaccination coverage and the incidence of vaccine-preventable diseases (VPDs) in the Republic of Korea. National vaccination coverage of 10 essential vaccines administered to children between January-June 2019 and January-June 2020 was analyzed. The national incidence of selected VPDs was compared for the corresponding periods. During the COVID-19 outbreak, the vaccination rate in children aged 0-35 months in Korea did not decrease significantly, whereas the vaccination rate for children aged 4-6 years decreased by 1.4-1.9%. The overall incidence of VPDs decreased by 10-50% between 2019 and 2020, especially with varicella. Thus, the COVID-19 pandemic did not result in a decrease in vaccination coverage among Korean children, which prevented a surge in VPD incidence. Maintaining essential vaccination coverage without interruption is important during the response to the COVID-19 pandemic.

Bombyx mori kynurenine 3-monooxygenase gene editing and insect molecular breeding using the clustered regularly interspaced short palindromic repeat/CRISPR associated protein 9 system.

Genome editing by clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR associated protein (Cas)9, a third-generation gene scissors, and molecular breeding at the genome level are attracting considerable attention as future breeding techniques. In the present study, genetic and phenotypic analyses were conducted to examine the molecular breeding of Bombyx mori through CRISPR/Cas9-mediated editing of the kynurenine 3-monooxygenase (KMO) gene. The synthesized guide RNAs (gRNAs) were analyzed using T7 endonuclease I after introduction into the BM-N silkworm cell line. To edit the silkworm gene, K1P gRNA, and Cas9 complexes were microinjected into silkworm embryos. After microinjection, the hatching rate and the incidence of mutation were determined as 18.1% and 60%, respectively. Gene mutation was verified in the heterozygous G0 generation, but no phenotypic change was observed; however, certain embryos and moths produced through sib-mating had significant differences compared to the wild-type. In successive generations, a distinct phenotypic change was also observed by continuous mating. Thus, although there are limitations in the phenotypic expression in breeding through the induction of deletion mutations, as in the present study, the process is believed to yield successful results within a shorter period compared to traditional breeding and is safer than transgenic technology.

Pathophysiological role of endogenous irisin against tumorigenesis and metastasis: Is it a potential biomarker and therapeutic?

In the last few decades, there has been notable progress in understanding the molecular and cellular basis of the complex process involved in cancer. In this context, tumor-promoting inflammation, dysregulation of apoptotic signaling, tissue invasion and metastasis, and cancer microenvironment have recently attracted interest from researchers. Irisin is a hormone released by muscles during exercise and it directly acts on key functional cells involving energy metabolism and homeostasis. Recently, many studies have reported the anticancer effect of irisin against different types of cancer. Translation of these findings to clinical practice for the diagnosis and treatment of several types of cancer is urgently required. In this review, we summarized preclinical and clinical studies on the anticancer effects of irisin in various types of cancer, and also discussed the mechanisms activated by irisin to suppress cancer pathogenesis. We further discussed the serum level of irisin related to different types of cancer to understand more clearly the association between irisin concentration and tumor burden. This review may serve as a solid foundation for researchers and physicians to support basic and clinical studies on irisin as a promising strategy for early diagnosis and treatment of a various types of cancers.

Purification, crystallization and preliminary X-ray crystallographic analysis of the UDP-N-acetylmuramoyl-tripeptide-D-alanyl-D-alanine ligase (MurF) from Acinetobacter baumannii.

The emergence and global spread of multidrug-resistant Acinetobacter baumannii strains are major threats to public health. Inhibition of peptidoglycan biosynthesis is an effective strategy for the development of antibiotics. The ATP-dependent UDP-N-acetylmuramoyl-tripeptide-D-alanyl-D-alanine ligase (MurF) that is responsible for the last step of peptidoglycan biosynthesis is a validated target for the development of antibiotics. Crystals of A. baumannii MurF in complex with ATP were grown by the microbatch crystallization method at 295 K. The crystals belonged to space group P3221, with unit-cell parameters a=b=85.42, c=129.86 Å. Assuming the presence of one molecule in the asymmetric unit, the solvent content was estimated to be about 54.32%.

ATP-binding mode including a carbamoylated lysine and two Mg(2+) ions, and substrate-binding mode in Acinetobacter baumannii MurF.

MurF adds d-Ala-d-Ala dipeptide to UDP-N-acetylmuramyl-l-Ala-γ-d-Glu-m-DAP (or l-Lys) in an ATP-dependent manner, which is the last step in the biosynthesis of monomeric precursor of peptidoglycan. Here we report crystal structures of two MurF-ATP complexes: the MurF-ATP complex and the MurF-ATP-UDP complex. The ATP-binding mode revealed by the crystal structure of the MurF-ATP complex confirms the previous biochemical demonstration that a carbamoylated lysine and two Mg(2+) ions are required for enzyme activity of MurF. The UDP-MurF interactions observed in the crystal structure of the MurF-ATP-UDP complex depict the characteristic substrate-binding mode of MurF. The emergence and dissemination of multidrug-resistant Acinetobacter baumannii strains are great threats to public health. Therefore, the structural information on A. baumannii MurF as a validated target for drug discovery will provide a framework to develop antibacterial agents against multidrug-resistant A. baumannii infections as well as to understand the reaction mechanism of MurF.

Complete Genome Sequence of Mycobacterium bovis BCG Korea, the Korean Vaccine Strain for Substantial Production.

Mycobacterium bovis bacillus Calmette-Guérin (BCG) is the only vaccine available against tuberculosis, and the strains used worldwide represent a family of daughter strains with distinct genotypic characteristics. Here, we report the complete genome sequence of M. bovis BCG Korea, the strain that will be actually used in Korea for vaccine production.