Basic Bacterial Morphology Bacteria and fungus (mold and yeast) grow in a variety of shapes, sizes and colors. Although it is difficult to make a definite identification of cultures growing in broth or solid media many have distinguishing characteristics that give us clues to identification. Many Microbiologist can make a tentative identifications by growth characteristics but definitive id requires further testing (ie Gram stain, chemical testing, etc). The palm of a hand print print done on TSA agar. There is a mix of different textured and colored colonies on the plate some bacterial some yeast. By looking at color, texture, growth times and various growth temperatures you can get an idea as to what is on the plate. Ex: the orange colonies are yeast and tend to grow better at room temperature or refrigerated temperatures where the large colony on the left ( Bacillus spp) and the white colonies ( Staphylococcus ) grows well at body temperature. Further testing need
Popular posts from this blog
Oxygen Requirements: Fluid Thioglycolate Media A B C D E Organisms grown in Fluid Thioglycollate Media, a reducing media that uses sodium thioglycolate to chemically combine with dissolved oxygen to deplete the oxygen in the media. The top portion of the tube contains oxygen while the bottom of the tube is lacking molecular oxygen. All organism except for Neisseria sicca were grown for 48 hours at 37 o C. Neisseria sicca was grown for 72 hours at 37 o C for best results. Note: Both N. sicca and C. butrycium were grow in supplemented Thioglycollate Media. A calcium chip can be seen in the bottom of the tube for N. sicca which is used as a buffer. This media is aslo supplemented with vitamin K. Note: I buy prepared thioglycolate media and many times the media is "jostled" in shipping. I will autoclave the tubes to d
Nitrate Reduction/Nitrate Reductase Test Some bacterial species are able to reduce nitrate (NO3) to nitrite (NO2) using the enzyme nitrate reductase in an anaerobic process by using molecules other then oxygen, nitrate, as a terminal electron acceptor. To determine if a bacteria is able to reduce nitrate they are grown in a nitrate broth and a series of chemical are added to detect nitrate reduction. (A) (B) (C) Nitrate reduction test for the reduction of nitrate in nitrate media, to determine if the bacteria contains nitrate and/or nitrite reductase. Organism were incubated for 48 hr's at 37 degree's in nitrate media then reagents added. The addition of these reagents test for the presence of nitrites and the media will turn red if nitrites are present. Nitrate broths after the addition of 10 drops reagents A (sulfanilic acid in acetic acid) and B (nn-di
Comments
Post a Comment