Download Prescott`s Microbiology, 9th Edition Chapter 29 –Methods in

Prescott’s Microbiology, 9th Edition
Chapter 29 –Methods in Microbial Ecology
GUIDELINES FOR ANSWERING THE MICRO INQUIRY QUESTIONS
Figure 29.4 What happens to the flow stream in fluorescence activated cell sorting (FACS)?
The droplets have a net electrical charge on them, and thus have their flight directed by electric
fields via attraction or repulsion. Thus, FACS will sort and collect droplets into different bins,
based on set fluorescence parameters.
Figure 29.7 Under what circumstances would one use epifluorescence microscopy, rather than
flow cytometry, and vice versa?
Epifluoresence allows you to directly visualize the cells, and see where the fluorescence is inside
the cell. Flow can count large numbers of cells is a short period of time, but you don’t directly
visualize them.
Figure 29.8 How many different phylotypes appear to be represented by this DGGE?
Each sample appears to have three different sequences.
Figure 29.9 How do phylochip differ from the microarrays discussed in chapter 18 (p. 434)?
In technical details, both microarrays are the same. With the phylochip application, the probes on
the chip match 16S sequences unique to many different species. With the expression microarray,
the probes match different gene sequences so the expression of many different genes can be
simultaneously determined.
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