O1) One of the advantages of some newly developed rapid identification tools is that pure cultures are not needed. Why is a pure culture necessary for biochemical tests such as the Enterotube, but not for DNA probes?
For biochemical tests, such as the Enterotube, if the culture contains any unwanted organisms, it could skew the results of the biochemical test potentially producing false-positive or false-negative results of the test. You use the Enterotube test to find one unknown microorganism; therefore, if you don't use a pure culture, you don't know for sure what microorganism you identified with your results. On the other hand, when and microorganism is difficult to culture/grow you use a DNA probe. DNA probes bind directly to predefined nucleic acid sequences, which basically identifies the microorganism even when surrounded by other microorganism's. Therefore, a pure culture is unnecessary.
2) Name two diseases that may be diagnosed by Western Blotting.
Lyme disease, HIV, Bovine spongiform encephalopathy, Hepatitis B.
3) The use of culture-independent techniques has increased our understanding of microbial diversity without cultivation. Therefore, do microbiologists still need to attempt to grow new microbial species? Explain.
Man of the microbes that exist cannot be cultivated by conventional methods on conventional growth media and have remained unknown. IN recent years, however, isolation and identification methods have become much more sophisticated, and microbes that fill these niches are being identified - many without being cultivated. Until now, microbiologists have identified and described only about 5000 bacterial species, of which about 3000 have been listed in Bergey’s Manual. The true number may be in the millions. One report indicates that a single gram of soil may contain 10,000 or so bacterial types, so yes. Microbiologists need to attempt to grow many more microbial species.
4) Bacteroides and Escherichia are both gram-negative rods found in the large intestine. Why are they in different phyla?
The gammaproteobacteria species Escherichia coli is one of the most common inhabitant of the human intestinal tract and is probably the most familiar organism in microbiology. Its presence in water or food is an indication of fecal contamination. It’s not usually pathogenic, however, it can be a cause of urinary tract infections and certain strains produce enterotoxins that cause diarrhea and occasionally cause very serious f