Critical thinking questions

1. Suppose you wanted to isolate a microorganism that was a mesophilic, degraded cellulose and was mi-croaerophilic. What conditions would you have to provide to isolate such a microorganism in the labo­ratory? Where would you obtain the inoculum for es­tablishing the culture?

2. Some bacteria that live in deep ocean waters are ob­ligate barophiles that tend to lyse or rupture when brought to normal atmospheric pressures. What spe­cial requirements would these bacteria need to survive in their high pressure environment? Why can't they survive at the ocean surface? How can they be cul­tured in the laboratory?

3. Why would you want to distinguish between the num­bers of live bacteria and dead bacteria in a popula­tion? How would you go about doing this? How would you deal with viable nonculturable bacteria?

4. It takes about 60 minutes to replicate the bacterial chromosome. Given that every daughter cell formed by binary fission must have a complete bacterial chro­mosome, how can some bacteria reproduce every 30 minutes?

5. Why does the clinical microbiology laboratory em­ploy so many different methods for isolating and iden­tifying pathogenic microorganisms? Why can't one set of standardized conditions be employed?

Readings

Atlas RM and R Bartha: 1993. Microbial Ecology: Fundamentals and

Applications, ed. 3, Menlo Park, California; Benjamin/Cummings. A text describing the ecology of microorganisms that includes chap­ters on the effects of environmental conditions on the growth of mi­croorganisms.

Brock TD (ed.): 1986. Thermophiles: General, Molecular, and Applied Microbiology, New York, John Wiley.

Complete coverage of the thermophilic bacteria by an outstanding re­searcher in the field.

DeLong EF and AA Yayanos: 1985. Adaptation of the membrane

lipids of a deep-sea bacterium to changes in hydrostatic pressure,

Science 228:1101-1103. Discusses the physiological effects of hydrostatic pressure on marine bacteria and the role of their membranes on their ability to adapt to this environment.

Dworkin M: 1985. Developmental Biology of the Bacteria, Menlo Park,

CA; Benjamin/Cummings. Describes the special features of bacterial growth.

Ingraham JL, О Maaloe, FC Neidhardt: 1983. Growth of the Bacterial

Cell, Sunderland, MA; Sinauer Associates.

Explains biological principles and molecular aspects of bacterial growth.

Jannasch HW and MJ Mottl: 1985. Geomicrobiology of deep-sea

hydrothermal vents, Science 216:1315-1317.

A fascinating report on the microorganisms growing in deep-sea ther­mal vents and how they support the surrounding biological commu­nity.

Postgate JR: 1994. The Outer Reaches of Life, New York; Cambridge

University Press.

Describes the fascinating adaptations of microorganisms that permit survival under extreme environmental conditions.

Slater JH, R Whittenbury, JWT Wimpenny: 1983. Microbes in Their

Natural Environments, Thirty-Fourth Symposium of the Society for

General Microbiology, England, Cambridge University Press. A series of papers on the growth of microorganisms in various natural habitats.

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