ABSTRACT
The assessment of airborne viruses in air is a critical step in the design of appropriate prevention and control measures. Hence, herein, we developed a novel wet-type electrostatic air sampler using a viral dissolution buffer containing a radical scavenging agent, and verified the concentration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in the air of hospital rooms inhabiting coronavirus disease 2019 (COVID-19) patients and public areas. RNA damage caused by corona discharge was negligible when Buffer AVL was used as the collecting electrode. The viral RNA concentration in the air of the room varied by patient: 3.9 × 103 copy/m3 on the 10th day after onset in a mild case and 1.3 × 103 copy/m3 on the 18th day in a severe case. Viral RNA levels were 7.8 × 102 and 1.9 × 102 copy/m3 in the air of the office and food court, respectively, where people removed their masks when eating and talking, but it remained undetected in the station corridor where all the people were wearing masks. The assessment of airborne SARS-CoV-2 RNA using the proposed sampler can serve as a basis for the safe discontinuation of COVID-19 isolation precautions to identify exposure hotspots and alert individuals at increased infection risks.
ABSTRACT
Purpose: The aneuploidy and sex concordance between cell-free DNA in spent culture media (SCM) and DNA from whole embryo with respect to different morphological grading were examined to evaluate the feasibility of non-invasive preimplantation genetic testing for aneuploidy (niPGT-A). Methods: A total of 46 pairs of embryos and corresponding SCM were divided into two groups based on the morphological grade. DNA was extracted from 22 and 24 pairs of low- and high-grade embryos, respectively, and respective SCM followed by chromosomal analysis using next-generation sequencing. Aneuploidy study and sex determination were conducted for both groups, and concordance rates were calculated. Results: For low-grade embryos, 63.6% (14/22) were determined as aneuploidy by whole embryo analysis, and concordance rates were 54.5% (12/22) using niPGT-A. On the contrary, for high-grade embryos 41.7% (10/24) were determined as aneuploidy by whole embryo analysis, and concordance rates were 62.5% (15/24) using niPGT-A. The concordance rates were not statistically different between the low-grade and high-grade embryo groups (p = 0.804). For sex determination, concordance rates between whole embryo and SCM were 81.8% (18/22) and 87.5% (21/24) in low- and high-grade groups, respectively. Conclusion: Aneuploidy and sex evaluation by niPGT-A may be feasible for both morphologically low- and high-grade embryos.
ABSTRACT
In the mouse embryo, expression of zygotic genes starts in the S/G2 phase of the 1-cell stage and greatly increases during the 2-cell stage. Although the timing of zygotic gene activation (ZGA) is thus established, the mechanism regulating ZGA is poorly understood. Previous studies using reporter genes have suggested that a transcriptionally repressive state is established during the 2-cell stage and that the first and second rounds of DNA replication are involved in this process. To further elucidate the respective roles of the two rounds of DNA replication in ZGA, we analyzed the expression of four ZGA genes (hsp70.1, eif-1a, muerv and zscan4d) in embryos whose DNA replication was inhibited by treatment with aphidicolin, an inhibitor of DNA polymerase. Inhibiting the first round increased the expression levels of hsp70.1, eif-1a and zscan4d but decreased that of muerv, while inhibiting the second round increased the expression levels of all four genes. These results suggest that the transcriptionally repressive state seems to be established after the second round of DNA replication.
