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Although this volume is dedicated to honoring François Jacob, I would like my contribution to broaden the context by recalling the background within which the scientists of those times operated. The specific scientific accomplishments of Jacob will certainly be covered by the other contributors who collaborated with him. My handful of recollections presented here largely as vignettes is intended to give the reader a feeling for the elements, many social, that shaped the generation of scientists that included such central figures, Jacob, Lwoff, Monod. It is the tale of a generation trying to express its creativity in a world caught up in war, irrational values and unforgivable inhumanity. Even this limited account is a great story bringing us important lessons for thought., (Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.)

The papers from the Jacob and Monod groups that presented the operon model and repressor control of gene expression provided a paradigm that opened up the field of gene regulation. Following the set of papers published between 1958 and 1961, there ensued almost immediately a period of "normal science" as Thomas Kuhn has defined it. Most researchers applied the repressor model to their own systems. I suggest a number of factors that were responsible for the rapid acceptance of the Jacob-Monod model and inhibited suggestions for alternative mechanisms of regulation. Nevertheless, I argue that this adherence to the paradigm, including specifically control by repressors, may well have been necessary for the field to progress. Ultimately, the evolution of this field of study was to reveal the unexpected complexity to genetic regulation., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

A series of eight review articles that appear in the present issue of the Journal of Molecular Biology celebrates the 50th anniversary for the landmark publication of François Jacob and Jacques Monod entitled "Genetic Regulatory Mechanisms in the Synthesis of Proteins". In this publication, the authors presented a model for the regulation of gene expression deduced from genetic and biochemical studies. They proposed that a new class of genes, regulatory genes, would code for repressors that bind to operator sequences upstream of operons consisting of a group of catabolic or biosynthetic genes with related functions. Binding is controlled by small metabolites, substrates or end products. The repressors control the transmission of information from genes to mRNA that is translated into proteins. The present review articles demonstrate how this publication influenced our thinking and how it stimulated the studies on the regulation of gene expression all the way to present day epigenetics and systems biology., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Even today, the concepts developed by Jacques Monod during the course of his career remain at the core of modern biology. Looking back, Jacques Monod stands out as one of the giants who most strongly marked twentieth century science. He was endowed with intelligence, rigor, creativity, a relentless sense of deductive reasoning and a love of scientific elegance. His name will remain intimately associated with the birth, development and triumph of molecular biology. He was not only a brilliant scientist, but along with that he was a generous laboratory director who gave selflessly to his many students and co-workers. Yet in our minds, he will also remain a man with a profound moral commitment to any cause which he felt just. He was a true humanist., (Copyright 2010 Elsevier Masson SAS. All rights reserved.)

Between 1942 and 1956, Jacques Monod, Nobel Prize winner in Physiology/Medicine, contributed a number of papers to the Annales de l' Institut Pasteur, the ancestor of the journal "Research in Microbiology". Circumstances that led him to publish in the "Annales" are recalled here., (Copyright 2010 Elsevier Masson SAS. All rights reserved.)

The operon model was the last "great" discovery of molecular biology, and a decisive event for the entrance of molecular biology into embryology. But the work of Monod was not limited to the elaboration of this model. He was one of the founders of molecular biology, in the paradigm of which biologists still work. I focus on two episodes of Monod's career--his strong opposition to Lysenkoism and the elaboration of the allosteric model--to outline the ideas and convictions of the early molecular biologists., (Copyright 2010 Elsevier Masson SAS. All rights reserved.)

There are few appropriate single-copy genetic tools for most Burkholderia species, and the high level of antibiotic resistance in this genus further complicates the development of genetic tools. In addition, the utilization of resistance genes for clinically important antibiotics is prohibited for the bioterrorism agents Burkholderia pseudomallei and Burkholderia mallei, necessitating the development of additional nonantibiotic-based genetic tools. Three single-copy systems devoid of antibiotic selection based on two nonantibiotic selectable markers, tellurite resistance (Tel(r)) and Escherichia coli aspartate-semialdehyde dehydrogenase (asd(Ec)), were developed to facilitate genetic manipulation in Burkholderia species. These systems include one mariner transposon, a mini-Tn7-derived site-specific transposon, and six FRT reporter fusion vectors based on the lacZ, gfp, and luxCDABE reporter genes. Initially, we showed that the random mariner transposon pBT20-Deltabla-Tel(r)-FRT efficiently transposed within Burkholderia cenocepacia, Burkholderia thailandensis, B. pseudomallei, and B. mallei. We then utilized the mini-Tn7-Tel(r)-based transposon vector (mini-Tn7-Tel(r)-betBA) and a transposase-containing helper plasmid (pTNS3-asd(Ec)) to complement the B. thailandensis DeltabetBA mutation. Next, one of the FRT-lacZ fusion vectors (pFRT1-lacZ-Tel(r)) was integrated by Flp (encoded on a helper plasmid, pCD13SK-Flp-oriT-asd(Ec)) to construct the B. thailandensis DeltabetBA::FRT-lacZ-Tel(r) reporter fusion strain. The betBA operon was shown to be induced in the presence of choline and under osmotic stress conditions by performing beta-galactosidase assays on the B. thailandensis DeltabetBA::FRT-lacZ-Tel(r) fusion strain. Finally, we engineered B. thailandensis DeltabetBA::FRT-gfp-Tel(r) and DeltabetBA::FRT-lux-Tel(r) fusion strains by utilizing fusion vectors pFRT1-gfp-Tel(r) and pFRT1-lux-Tel(r), respectively. The induction of the betBA operon by choline and osmotic stress was confirmed by performing fluorescent microscopy and bioluminescent imaging analyses.

Expression of the bacterial luciferase (lux) system in mammalian cells would culminate in a new generation of bioreporters for in vivo monitoring and diagnostics technology. Past efforts to express bacterial luciferase in mammalian cells have resulted in only modest gains due in part to low overall expression of the bacterial genes. To optimize expression, we have designed and synthesized codon-optimized versions of the luxA and luxB genes from Photorhabdus luminsecens. To evaluate these genes in vivo, stable HEK293 cell lines were created harboring wild type luxA and luxB (WTA/WTB), codon-optimized luxA and wild type luxB (COA/WTB), and codon-optimized versions of both luxA and luxB genes (COA/COB). Although mRNA levels within these clones remained approximately equal, LuxA protein levels increased significantly after codon optimization. On average, bioluminescence levels were increased by more than six-fold [5x10(5) vs 2.9x10(6) relative light units (RLU)/mg total protein] with the codon-optimized luxA and wild type luxB. Bioluminescence was further enhanced upon expression of both optimized genes (2.7x10(7) RLU/mg total protein). These results show promise toward the potential development of an autonomous light generating lux reporter system in mammalian cells.

Some problems of molecular genetics are considered. A special attention is paied to enzymology of genetic processes, in particular, to the mechanism of DNA replication, gene ingeneering and the structure and activity regulation mechanisms of genetic loci in higher organisms.