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).
Pregnancy. Spotting can occur in the early stages of pregnancy. If you have a missed period and you are spotting and have no other health concerns, it could be an indication that you are pregnant. Blood that's brownish in color during spotting is also another indication you might be pregnant.The reason it's brown is because your uterus is shedding old blood. miscarriage is when the fetus detaches from your uterus. However, in a miscarriage, the spotting will eventually turn heavy, so light spotting during pregnancy does not always mean you are miscarrying. A miscarriage cannot be avoided.