Last updated 4 years ago
In pink, enzyme histone deacetylase (HDA6) stands out against background blue-tinted DNA in nucleus of an Arabidopsis plant cell. HDA6 concentrates in nucleolus (top center), where ribosomal RNA genes reside. The enzyme.. silences ribosomal RNA genes from one parent while those from other parent remain active. Courtesy Olga Pontes, Craig Pikaard, geneticists Washington University, St. Louis.
16-cell human embryo on a pin, SEM - Stock Image - P680/0396
"Coloured SEM of a human embryo at the 16-cell stage on the tip of a pin. The ball of cells (yellow) of the embryo is known as a morula, a cluster of almost identical, rounded cells, each containing a central nucleus. This 16-cell embryo is about three days old. It is at the early stage of transformation from a single cell to a human composed of millions of cells. The cells multiply by repeated cleavage divisions (mitosis) and will form a hollow ball of cells (the blastocyst)."
APOD: 2011 December 5 - A Memorable Aurora Over Norway
A Memorable Aurora Over Norway (Dec 5 2011) Image Credit & Copyright: Ole Christian Salomonsen It was one of the most memorable auroras of the season. There was green light, red light, and sometimes a mixture of the two. There were multiple rays, distinct curtains, and even an auroral corona. It took up so much of the sky. In the background were stars too numerous to count, in the foreground a friend trying to image the same sight.