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Suggested Answers for Insight Questions, Foundations in Microbiology, 7th Edition, listed by chapter, number, and page location. A note to the users of these answers: These answers discuss some of the possible ways to approach the questions. They are not meant to be exhaustive in depth, but can offer information, suggestions, and points of view that will be helpful in understanding some of the concepts covered in the Insight and the chapter. Furthermore, they are not the final word--you may have thought of some other explanations that are just as valid. It is hoped they will serve to stimulate class discussion and inspire further research. 26.1, pg. 794 – Greenhouse Gases, Fossil Fuels, Cows, Termites, and Global Warming Microbes can adapt to a particular habitat, even one that is more extreme, but not all microbes can adapt as rapidly as would be necessary. An ocean temperature that warms even a few degrees over a relatively short time can adversely affect the growth of phytoplankton. The algae may die off in great numbers before they can adjust their metabolism to operate at higher temperatures. Scientists have already begun to observe such a scenario in the northern Pacific Ocean. Reduction in the phytoplankton affects all other organisms that rely on them as the primary producers, even other microbes, such as zooplankton and bacteria, and this extends on up the food chain. The important point is, that all life is interconnected, and if climate changes the abiotic environment and permanently alters a well established ecological balance, it can be lost forever. Another factor is that microbes often exist in close associations and biofilms with other organisms in soil and around plant roots. If the more sensitive members of these communities are wiped out by global climate change, this can be expected to have far-reaching affects. The warming of the earth affects the hydrologic cycle, the carbon cycle, and probably other biogeochemical cycles. One of the problems we face is that the ecological systems are extremely complex and we do not yet know or understand all of the factors or potential effects of these changes. 26.2, pg. 798 – Bioremediation: The Pollution Solution? One possible technology would involve production of specialized enzymes tailor-made to degrade certain pollutants into harmless residues. These enzymes could be manufactured in large quantities by genetic engineering techniques and designed to remain functional in the environment for an extended period. Another potential solution, and one that has been adopted in parts of Europe is to convert solid waste into useful products. The waste items are sorted and compressed or incinerated into blocks that can be used as building materials. Even microbes cannot degrade a lot of the materials being dumped into land- fills. So they will sit there for eons, and who knows what the ultimate effect will be? Recycling is in fact an excellent way to manage waste. Many large municipalities recycle nearly every type of household waste, and large industries have built up around the capture and reuse of such materials. One recent process in development can convert practically any household waste into biodiesel that could power automobiles. 26.3, pg. 804 – The Waning Days of a Classic Test The coliform genera that are similar to E. coli but not as indicative of fecal contamination are primarily Enterobacter, Klebsiella, and Citrobacter. (See page 608) These bacteria are normal residents of the large intestine, but can also be found in soil, water, and on plants. Their presence in food is often due to environmental contamination rather than contact with feces. These bacteria are generally not highly virulent and are primarily opportunistic in their mode of attack. In addition, they tend to cause infections of organs or organ systems other than the intestine. Enterobacter is often associated with surgical infections and septicemia; Citrobacter occasionally infects the urinary tract and blood in debilitated patients; Klebsiella pneumoniae is a frequent cause of hospital-acquired pneumonia and wound infections. It all comes down to susceptibility and portal of entry. Most people who ingested the iced tea were not immunocompromised and others did not offer the correct portal of entry to allow invasion. The normal host defenses would have kept the microbes in check. Probably every day we ingest bacteria in our food that are listed as potential pathogens, but we do not get infected by them. If the bacteria in the iced tea had been one of the variants of E. coli that infect the intestine, the outcome would have turned out quite differently!