EDITORIAL

The Great Wall Symposium

The second Great Wall symposium recently held inLisbon, Portugal featured the latest advances in the field

of peptidoglycan metabolism. Over the past several years,the peptidoglycan molecule has received renewed attention.With new technologies available, microbiologists are re-thinking aspects of peptidoglycan structure. In addition,microbial genetics is providing new insight into how the cellorchestrates the synthesis, breakdown, and recycling of themolecule. Further, new data are emerging that demonstrate arole for peptidoglycan or peptidoglycan derivatives incommunication among bacterial cells of the same species,different species, and between bacterial cells and eukaryotichost organisms. And finally, peptidoglycan is being recog-nized as a signaling molecule not only in pathogenesis, butalso in the normal, beneficial interactions that animals havewith their coevolved microbial partners.

The field of the bacterial cell wall really emerged in the1940s and 1950s with the clinical use of penicillin G and thestudies of its mode of action. The 50s–60s led to seminaldiscoveries on the bacterial cell wall, in particular, the Parknucleotides, precursors of the peptidoglycan, and the peni-cillin-binding proteins, by Park and Strominger among otherresearchers. In the 70s, Spratt attributed for the first time aspecific role of some of the penicillin binding protein (PBP) incell shape, while in the 80s, Tomasz dissected the mecha-nisms of the emerging resistance to b-lactams in major Gram-positive pathogens with the identification of PBP2a in Sta-phylococcus aureus and the mosaic PBPs in Streptococcuspneumoniae. Despite the importance of the field, the interestwaned slowly away in the 90s. The last meeting dedicated tostudies on peptidoglycan took place in 1995 in Lago diGarda, Italy and contributions to this meeting were pub-lished in two volumes of MDR (Microbial Drug Resistance1996; Vols. 2 and 3). The remerged interest in the field ofpeptidoglycan research occurred around the year 2000 withtwo important discoveries: (1) the characterization of bacte-rial cytoskeletal proteins and their role in driving cell wallsynthesis and the corresponding shape of a bacterium, and

(2) the discovery of innate immune receptors both in modelsystems such as Drosophila (through peptidoglycan rec-ognition proteins) and in mammals (through the Nodproteins) involved in detecting bacteria through the sensingof their peptidoglycan. As a consequence of the redis-covered interest in peptidoglycan by microbiologists, cellbiologists, and immunologists, Miguel de Pedro, JosephDillard, and Margaret McFall-Ngai organized in Baeza,Spain, October 4–6, 2010, a first meeting exclusively fo-cused on peptidoglycan research. This first small meetingattended by around 50 researchers was a real success andimmediately stimulated the organization of a secondmeeting that took place in Lisbon, Portugal, September 28–30, 2011. The current name of the meeting was inspired bya review paper published in 2006 ‘‘Breaching the greatwall: peptidoglycan and microbial interactions.’’

The symposium was an immediate success as the initialnumber of participants of 100 had to be expanded to 120without being able to accommodate all the researchers whowere interested in attending. Some of the science presentedin the meeting is featured in this special issue of MicrobialDrug Resistance that illustrates some of the advances thatoccurred in the last 16 years since the meeting in Lago diGarda, Italy. The renewed interested in the field is furtherillustrated with the organization of the third Great WallSymposium that will take place at the Institut Pasteur inParis, September 23–25, 2013.

The organizing committee:Ivo G. Boneca

Jonathan DworkinDavid Roper

The local committee:Sergio Filipe

Adriano HenriquesAna Madalena Ludovice

Mariana Gomes Pinho

MICROBIAL DRUG RESISTANCEVolume 18, Number 3, 2012ª Mary Ann Liebert, Inc.DOI: 10.1089/mdr.2012.1501

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