Establishment of national standards of SARS-CoV-2 variants in Taiwan.

Objectives: In response to the pandemic, the Taiwan Food and Drug Administration (TFDA) established an initial SARS-CoV-2 RNA national standard based on the original Wuhan strain. However, with the depletion of the first national standard and continued mutation of the virus, the establishment of new national standards was imminent.

Methods: Hence, new candidate national standards were established by heat-inactivation for 30 min for six representative strains of SARS-CoV-2, comprising the original strain and five variants with anticipated concentrations of 7.

BMP8A sustains spermatogenesis by activating both SMAD1/5/8 and SMAD2/3 in spermatogonia.

Mutation in either of the genes encoding bone morphogenetic protein (BMP) 8A or 8B ( or ) causes postnatal depletion of spermatogonia in mice. We found that , but not , was expressed predominantly in the neonatal mouse spermatogonia. Although most BMPs induce activation of SMADs 1, 5, and 8 (SMAD1/5/8), but not SMADs 2 and 3 (SMAD2/3), we found that BMP8A induced signaling through both sets of transcription factors.