Mercedes Berlanga

Berlanga, Mercedes

Hemeroteca Cientifica Catalana

BOOK REVIEWSINTERNATIONAL MICROBIOLOGY (2011) 14: 59-60ISSN: 1139-6709 www.im.microbios.org The lure of bacterial genetics. A tribute to JohnRothSTANLEY MALOY, KELLY T. HUGHES, JOSEP CASADESÚS (EDS)2011. ASM Press, Washington, DC362 pp, 18 × 26 cmPrice: $ 149.95ISBN 978-1-55581-538-7When Louis Pasteur and Robert Koch discovered the essen-tial role played by microbes in human life, microbiologybecame a science with practical implications for the well-being of humankind, but with scarce importance for the coreof biology. All that changed beginning in the 1940s. Studiesstarted in the 1940s but developed in the 1950s and early1960s were able to show that mutations in bacteria are spon-taneous, that prokaryotes can exchange genetic material, andthat this material is DNA. These studies provided evidencefor the unity of genetics and established microbiology as afundamental discipline in biology. In 1961, the discovery ofinduced enzyme synthesis (the “operon theory”) was anoth-er essential contribution of microbes to biology. Not a singlemicrobial species is characterized by a specific and fixedmetabolic pattern. Instead, by altering their enzymatic equip-ment, microbial cells can adapt to new environments. Thisprocess allows new characteristics to be introduced into anotherwise genetically constant microbial cell in response toenvironmental changes. The lure of bacterial genetics. A tribute to John Roth waswritten and edited by former students of John Roth and bycolleagues who are specialists in the field of bacterial genet-ics. Over the years, John Roth has inspired many undergrad-uates to pursue graduate training; he has also encouragedmany graduate students and postdoctoral fellows, who laterdeveloped successful careers in academia or industry. Thelure of bacterial genetics could be considered John Roth’slegacy. The contributions of the invited authors are groupedin seven sections comprising 33 chapters that provide anoverview of the field of bacterial genetics and how it hasevolved. The chapters are based on the experience andexpertise of the authors and reflect the most important tri-umphs and mishaps that occurred along the paths to numer-ous observations and discoveries. Section I (Chaps. 1–4) traces John Roth’s interest in bac-terial genetics. John Roth himself (Chap. 2) draws on his ownextensive lecture experience to provide practical guidelinesfor giving a seminar to graduate students. This section alsorelates the experiences of students (now investigators) in theadvanced bacterial genetics course regularly held at ColdSpring Harbor, with special reference to the topics taught byJohn Roth. The courses held each summer at Cold SpringHarbor have long been popular with students, who while theyare there have no obligations other than to pursue their inter-est in science. Microorganisms must overcome a wide range of fluctuat-ing variables in their surroundings, which they do by modi-fying the expression of numerous genes in response to extra-cellular and intracellular conditions. Section II (Chaps. 5–11)provides several examples of this response: the biotin andproline operons, the D-galactose metabolic pathway, and theheme pathway.In 1965, when the genetic code was finally deciphered, itwas thought that triplet decoding would be immutable.Frameshift suppressors are tRNA mutants that can read four-letter codons and are thus able to correct mutations caused bysingle-base additions to mRNA. A breakthrough discovery—made between 1985 and 1987—was the demonstration thatframeshifting plays an essential role in gene expression.These topics are discussed in Section III (Chaps. 12–14).In Section IV (Chaps. 15–20), several examples are pro-vided of the relationship between genetics and phy-siology/metabolism, such as the genetic-physiological link inthe swarming response of Serratia, genetically based con-tact-dependent growth inhibition, adaptable pathways forhost infection by pathogenic bacteria, and bile-induced muta-genesis in Salmonella populations. Evolution is the result of genetic variation and selectionand is the fundamental strategy of life, allowing organisms toadapt to new environments and to adverse conditions.Genetic variations in bacteria occur by three distinct mecha-nisms: point mutation, genetic rearrangements, and lateralgene transfer. Genomics and genome sequencing studieshave corroborated that the relative positions of genes on thechromosome may influence their expression, mutationalbias, and rearrangement. These studies have also led toBOOK REVIEWSINT. MICROBIOL. Vol. 14, 201160insights into paralogous gene evolution and the reductiveevolutionary process (Section V, Chaps. 21–25). In adition toits “original” set of genes, the bacterial genome may containelements from other bacteria: genomic islands, plasmids, andbacteriophages (Section VI, Chaps. 26–32).Section VII (Chap. 33) is a reflection by John Roth on thefuture of bacterial genetics. We must study the organism tounderstand inheritance, mechanisms of gene regulation, etc.,as John Roth says in their “fish history.” “Never mind the fatfish, let’s study the boat.”One of the book’s contributors reminds us the words ofMark Twain: “There is something about science. One getssuch wholesale returns of conjecture out of such a triflinginvestment of fact.” In considering John Roth’s scientificcareer, we realize that contributions to basic science are oftwo kinds, making discoveries and solving problems. JohnRoth has excelled in both.I strongly recommend The lure of bacterial genetics foradvanced students and researchers in the field of microbiolo-gy. It is especially worthwhile reading during those all toofrequent times in the lab when an experiment fails. Accordingto John Roth, in that situation the best one can do is to ask theright questions in order to find the solution to the problemand to seek the advice of other people working in similarareas. Symbiosis in nature is the rule, not the exception; thesame should hold true for scientific endeavor. MERCEDES BERLANGAUniversity of Barcelonamberlanga@ub.edu

The lure of bacterial genetics. A tribute to John Roth

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