In 2003, the FDA approved generic gabapentin, and it's now made by several drug companies. An extended-release form of gabapentin is available under the brand name Horizant. In 2004, the drug maker Pfizer settled charges for marketing Neurontin for unapproved uses, and agreed to pay $430 million.
Although most diatoms are autotrophic, some heterotrophic or symbiotic species can be found in particular habitats. The living matter of each diatom is enclosed in a shell of silica that it secretes. These shells are marked by minute pores or depressions that allow the living organism access to its environment.iatom (dÄªËÉtÅmË, âtÅmË) [ key ], unicellular organism of the kingdom Protista, characterized by a silica shell of often intricate and beautiful sculpturing. Most diatoms exist singly, although some join to form colonies.
Diatoms range considerably in size, the largest species being about 2-mm and the smallest being only a few micrometers long. The âpennateâ diatom shown below is a little over 200-micrometers long. Such long, skinny pennate Diatoms are the most common form. Equally common is the gold or yellow color. This is because they have a large amount of yellow carrotenoid pigment and xanthophyll pigment that masks the green color of their Chlorophyll. Many Diatoms are motile, moving slowly, but steadily. Motion can be useful, if you live at the bottom of a pond and need to get from a dark areas to the sunlight. Diatoms are very difficult for us ordinary mortals to identify, since their body plan is basically quite simple and they are, pretty much, all the same color. The two tests fit together like the two parts of a Petri Plate, and the assembly is called a âvalveâ. Essentially, Diatoms are either pennate or âcentricâ.