Prevalence of Parainfluenza Viruses in Seoul, 2021 - 2022.

BACKGROUND: Parainfluenza virus (PIV) is a significant etiological agent of acute lower respiratory tract infections (ALRIs) in infants and young children. The present study has been conducted to investigate the prevalence of recently identified respiratory viruses. METHODS: In total, 543 oropharyngeal or nasopharyngeal swab samples collected from hospitalized patients with acute respiratory symptoms (ARS) between January and December 2021 (5,653 females and 4,950 males) were tested for respiratory viruses using RT-PCR. RESULTS: At least one respiratory virus was detected by RT-PCR in 119 out of 175 samples (68%). The most frequently detected virus was human rhinovirus (HRV) (34, 6.5%), followed by human parainfluenza viruses (HPIVs) (19, 3.6%), human bocavirus (HBoV) (8, 1.5%), human adenovirus (HAdV) (7, 1.3%), and human respiratory syncytial virus (HRSV) (4, 0.8%). HPIV-3 accounted for 3.6% (19/175) of all viral pathogens and was the second most frequently detected viral pathogen in our study. HPIV-3 infections peaked in the fall (November) of 2021. Phylogenetic analysis of the coding region of the viral protein HA revealed that all 35 (100%) of 35 HPIV-infected patients were infected with HPIV-3. CONCLUSIONS: HPIV was an important causative pathogen associated with ALRI in children hospitalized in Korea in the late fall of 2021, as the social distancing rules for COVID-19 were relaxed. These findings highlight the im-portance of HPIV as a cause of ALRI.

Biocatalytic resolution of glycidyl phenyl ether using a novel epoxide hydrolase from a marine bacterium, Maritimibacter alkaliphilus KCCM 42376 [corrected].

As a continuous effort of developing highly enantioselective epoxide hydrolase from marine microorganisms, it was found that Maritimibacter alkaliphilus KCCM 42376 [corrected] was highly enantioselective toward racemic glycidyl phenyl ether (GPE). An open reading frame (ORF) encoding a putative epoxide hydrolase (EHase) was cloned from the genome of Maritimibacter alkaliphilus KCCM 42376 [corrected], followed by expression and purification in Escherichia coli. The purified EHase (REH) hydrolyzed (S)-GPE preferentially over (R)-GPE. Enantiopure (R)-GPE from kinetic resolution of 29.2 mM racemic GPE using the purified REH could be obtained with enantiopurity of more than 99.9% enantiomeric excess (ee) and 38.4% yield (theoretical, 50%) within 20 min (enantiomeric ratio (E-value): 38.4). The enantioselective activity of REH toward GPE was also confirmed by the analysis of the vicinal diol, 3-phenoxy-1,2-propanediol. To our knowledge, this study demonstrates the highest enantioselective resolution of racemic GPE using a purified biocatalyst among the known native EHases.