Ploidy and local environment drive intraspecific variation in endoreduplication in Arabidopsis arenosa.

Premise: Endoreduplication, nonheritable duplication of a nuclear genome, is widespread in plants and plays a role in developmental processes related to cell differentiation. However, neither ecological nor cytological factors influencing intraspecific variation in endoreduplication are fully understood.

Methods: We cultivated plants covering the range-wide natural diversity of diploid and tetraploid populations of Arabidopsis arenosa in common conditions to investigate the effect of original ploidy level on endoreduplication.

The duration of SARS-CoV-2 shedding in patients recovering from COVID-19.

The knowledge of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) shedding is highly relevant to the diagnosis, treatment and follow-up of patients with COVID-19 (coronavirus disease 2019). Deep nasopharyngeal swabs repeatedly collected from a cohort of one hundred patients with COVID-19 were tested for SARS-CoV-2 RNA using RT-PCR (real-time polymerase chain reaction). The median period of viral genome detectability was 15 days.

Crop-to-wild hybridization in cherries-Empirical evidence from .

Crop cultivation can lead to genetic swamping of indigenous species and thus pose a serious threat for biodiversity. The rare Eurasian tetraploid shrub (ground cherry) is suspected of hybridizing with cultivated allochthonous tetraploid and autochthonous diploid . Three taxa (447 individuals of , 43 of and 73 of ) and their hybrids (198 individuals) were evaluated using analysis of absolute genome size/ploidy level and multivariate morphometrics.

The secondary antibody response induced in tissue cultures.

The conditions for induction of memory cells (B-MC) and evocation of the secondary antibody (Ab) response in tissue cultures (TC) were estimated. (1) In vivo primed B-MC cells were isolated 6-150 d after priming and stimulated in TC with different doses of sheep red blood cell (SRBC) antigen. The Ab response has a strict time and dose dependence: only small doses (10(5)) evoke a secondary response, high doses (10(8), 10(9)) a state of immediate tolerance.