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43 of 46 people found the following review helpful:
5.0 out of 5 stars
You're playing host today, May 11, 2008
You didn't possess a single one when you were born. Now, there are trillions of them, mostly enjoying the warm hospitality of your gut. If you are recently born, they may have been put into you on purpose. They are the famous/infamous Escherichia coli microbes of our inner selves - billions of them residing peacefully in each of our intestinal tracts. Carl Zimmer has added yet another gem in his crown as North America's premier science writer with this comprehensive and insightful account. Zimmer's talent lies in taking up serious science that deals with complex issues, and then putting it down in a way that seizes and holds your interest. More importantly, he informs you on topics relevant to your daily life - and prompts you to think about future decisions. While the subject may seem off-beat or esoteric, rest assured that "Microcosm" is aptly titled, with a host of life's secrets tucked away in how this microbe lives.
The microbe was first identified in 1885 by Theodore Escherich, who was struck by the "massive, luxurious growth" it could achieve. He dubbed it "a common bacteria of the colon", having no idea of its prowess or future role. Renamed Escherichia coli in the following century, the microbe entered an unexpected role in research - from medicine to evolutionary biology. Zimmer stresses this role and its importance in science, technology, business and even government through this account. Understanding those roles is fundamental to understanding the importance of this fine book - and why it's important for you to read it.
E. coli long played an enigmatic role in science - it was "discovered" more than once. Microbiology, not unlike palaeoanthropology, was once divided between the "splitters" and the "lumpers". Was each similar but distinct new organism a new species or just a variation on a theme. In E. coli's case, the "lumpers" prevailed and Zimmer explains clearly about "strains" of E. coli and their significance to us. The "K-12" strain is the one chiefly used as a standard for biological research. It's considered harmless to humans - as one researcher demonstrated by drinking a water glass filled with it. On the other hand, not long after Escherich's discovery, a Japanese scientist who was trying to fathom an outbreak of dysentery, isolated a bacterium resembling the German's find. Thinking it a different species, they named it "Shigella". It wasn't a new species, it was a strain of E. coli. That strain "O157:H7" plays a large role in this book because it is a serious disrupter of the human gut. And we brought it into existence.
The ubiquitous nature of E. coli and the various strains identified rendered it the workhorse of biological research laboratories. It is easy to modify by changing conditions like food supplies, temperature and assaulting it with viruses or chemicals all provide answers to how it works. In so doing, it also explains to us how life works, and how it likely worked in the past. Advances in technologies not only provided maps of E. coli's genome, it was found the genome could be tampered with successfully. Genes could be removed and inserted. So long as the basic life-support genes were left unscathed, E. coli would merrily perform for the scientists. Viruses might be resisted or even ousted after an infection. More astonishing to early researchers, it was seen that E. coli could pick up genes from a virus or other microbes and change its own genome. Today, there are those contending viruses inserting genes into DNA have driven evolution itself. Why do we have over 3 billion base pairs in a genome with only 18 thousand working genes? Invading viruses in our ancestors - and those of E. coli - have left traceable remnants.
The author doesn't confine himself to accounts of laboratory research and analyses. E. coli research has led to numerous social and even legal questions. The latter is best revealed in a lively account of the recent trial in Dover, Pennsylvania. There, a school board insisted on biology teachers reading a challenge to Darwin's theory of evolution by natural selection. The board demanded the adding of elements of the "intelligent design" proposal to the course. Zimmer's account of the testimony and witness exchanges resulted in the presiding judge dismissing "ID" as based on fallacious assumptions and bearing no scientific credibility. The social questions are broader and of greater concern. Forty years ago, as the potential for E. coli as a working tool to manipulate genetic information emerged, public outcry and researchers' own reflections on possibilities led to a brief interruption in "genetic engineering" efforts. With various safeguards in place, Zimmer explains, advances continued. He notes that fears about things like "Frankenfood" are generally baseless, given the long history of Nature's own tinkering with genetic processes. An informed, reasoned approach is required to determine which claims for benefits are possible and which threats, if any, need further addressing. He even manages to address issues in "exobiology", the prospect of either finding life on another planet, or introducing it there.
The wide sweep of topics, thoroughly and effectively addressed by this author make this book a treat to read and an asset to retain. It's Pulitzer or Aventis Prize material and deserves the highest recognition. [stephen a. haines - Ottawa, Canada]
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15 of 16 people found the following review helpful:
5.0 out of 5 stars
A Surprisingly Universal Microbiology, June 10, 2008
Inside your gut are maybe a hundred trillion cells. The number is an interesting one, because these cells sitting in your digestive tract outnumber the neurons, muscle cells, and other cells that make "you" by ten to one. In other words, by the numbers, your own cells are a machine that exists to keep a huger number of cells alive in your intestines. Among those trillions of cells is a small population of _Escherichia coli_, one of the world's most important and most studied bacteria. They may be tiny, but they are numerous and they are not simple, and the lessons within _Microcosm: E. coli and the New Science of Life_ (Pantheon) by science writer Carl Zimmer are that there is a complex cosmos of activity within _E. coli_, and there are relationships between one _E. coli_ and its fellow _E. coli_ and the other microbes churning in our guts, and there are relationships between _E. coli_ and the bigger animals that carry it. It is all as complicated as can be; we have come a long way in understanding some of these mysteries, but mysteries still abound. Zimmer's wonderful book keeps us from taking these humble bacteria for granted; as products of the same evolutionary processes that produced us, they have much in common with us.
Scientists make _E. coli_ a particular subject of investigation; it was one of the first microbes whose genome was fully mapped (1997). A few strains have toxins, but usually our own _E. coli_ are quietly going about their business and are a help to us. The intricacies of just one cell are astounding. An _E. coli_ has sixty million molecules which have to act just so to keep the bacterium living, and Zimmer examines a few of the intricate feedback systems involved. A team of microbiologists has succeeded in programming a computer with information on 1,260 of its genes and 2,077 of its chemical reactions; a huge program can predict what _E. coli_ will do, for instance, if starved for oxygen, and the model gets it right. But little _E. coli_ has been getting it right for ages. One of its pieces Zimmer pays special attention to is its flagellum, its means of mobility. Zimmer, in several pages devoted to flagella and Intelligent Design, tells again the story of the Dover, Pennsylvania, court decision that Intelligent Design had only religion going for it, not science, and thus could not be taught in public schools. A lawyer at the trial said, "We could probably call this the Bacterial Flagellum Trial", since the flagellum was discussed in detail, and was shown not to be "irreducibly complex", the supposed hallmark of designed systems that cannot be made any simpler and still remain operational. The ID proponents have only an "It's too wonderful not to have a designer" attitude, not experiments or evidence. Zimmer shows how there is within _E. coli_ molecular evidence that flagella are related to other bacterial systems, and that hypotheses built on this evidence show how natural selection was indeed sufficient to build flagella. Scientists can't say for sure that flagella were built in one certain way, but if the proposed steps of building reasonably come from the data, there is no reason to think that a deity somehow took pity on immobile bacteria and miraculously equipped them with motors.
"I look at life through a lens made of _E. coli_," writes Zimmer, and writes convincingly about how biologists are doing the same. Not only was the _E. coli_ genome among the first to be completely deciphered, they have been used to help understand how genes switch on and off. They are a foundation point for the study of molecular and now synthetic biology. They do a lot of the things we do. They sense nutrition molecules and go for them; they sense unattractive chemicals and run from them. They cooperate with other _E. coli_ and have a social life; they are not the loners scientists had originally thought, but can build their own microbial city. They have a type of chemical warfare that they deploy against enemies. They have a sex not in the way we do, but in their own way. They fight viruses and have virus-injected coding on their DNA just as we do. Zimmer frequently refers to the famous remark of biologist Jacques Monod, who said, "What is true for _E. coli_ is true for the elephant." There is hyperbole there, of course, but in one example after another, Zimmer's clear and enthusiastic prose beautifully demonstrates a biological and evolutionary universality.
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11 of 11 people found the following review helpful:
4.0 out of 5 stars
Good balance of science and story, May 26, 2008
It would have been easy to make this book very dry, and the author did an excellent job of balancing scientific detail with a good narrative. It includes just enough components of history and science to be complete without over-doing either area.
The author takes us from the isolation of E. coli in 1885 to, for example, current debates over how some mutations help bacteria survive environmental stress. Between these two benchmarks the author weaves a well-written story that covers what is known about E. coli and other bacteria. More importantly, he also explains why we know what we know. Of perhaps the greatest worth is the book's coverage of why natural selection is such an important scientific concept, using drug resistance as one of many examples.
A nice read for either the interested layperson or the professional.
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