TMPD. The oxidase test is a test used in microbiology to determine if a bacterium produces certain cytochrome c oxidases. It uses disks impregnated with a reagent such as N,N,Nâ²,Nâ²-tetramethyl-p-phenylenediamine (TMPD) or N,N-dimethyl-p -phenylenediamine (DMPD), which is also a redox indicator.he reagent is a dark-blue to maroon color when oxidized, and colorless when reduced. Oxidase-positive bacteria possess cytochrome oxidase or indophenol oxidase (an iron-containing hemoprotein). These both catalyze the transport of electrons from donor compounds (NADH) to electron acceptors (usually oxygen).
According to the American College of Obstetrics and Gynecology, about 15 to 25 percent of women have some amount of bleeding in their first trimesters. 1  Bleeding is less commonâand more concerningâif it occurs in the second or third trimester. What Spotting Looks Like Generally, the discharge you'll see if you experience spotting is brown, red, or pink in color and has a slightly gummy or stringy texture (because the discharge consists of a few drops of dried blood that's mixed with cervical mucus).
One day I noticed a little brown discharge when I went to the bathroom. Assuming it was just a visit from Aunt Flo, I went about my business and thought nothing of it. But after a couple of days, the spotting stopped, and I ended up having a positive pregnancy test a few weeks later. Implantation Bleeding or Period. Implantation bleeding can mimic menstruation, especially during those first few days of your period when you have a lighter flow or if you normally experience light periods, so you might feel confused when you start spotting.