Everett Peter Greenberg (born November 7, 1948) is an Americanmicrobiologist. He is the inauguralEugene and Martha NesterProfessor ofMicrobiology at the Department of Microbiology of theUniversity of WashingtonSchool of Medicine.^[5] He is best known for his research onquorum sensing, and has received multiple awards for his work.

Greenberg was born in 1948 inNew York City. When he was an infant, his family moved toSan Francisco then toSeattle, where he finished high school.^[2][4] He became interested inbiology, especiallyinvertebrate biology, after a field trip his biology teacher organized.^[4]

Greenberg was determined to study biology after a year atEverett Junior College (nowEverett Community College), and, instead of theUniversity of Washington which he thought was too big, opted forWestern Washington University inBellingham,Washington in 1966.^[2][4] He graduated with aBA in Biology in 1970.^[1]

He discovered his passion formicrobiology during hisundergraduate years, so despite initially planning to pursuebiochemistry forpostgraduate study, he eventually went to theUniversity of Iowa to conduct microbiology research, where he obtained hisMSc in Microbiology in 1972. Greenberg then started hisPhD at theUniversity of Massachusetts Amherst, and received his PhD in 1977.^[2]

After obtaining hisPhD, Greenberg spent time atHarvard University forpostdoctoral work.^[2] He joined the Department ofMicrobiology ofCornell University as an assistant professor in 1979,^[2] and was promoted toassociate professor in 1984.^[1] Greenberg went to the Department of Microbiology of theUniversity of Iowa as aprofessor in 1988, and returned toSeattle in 2005 when he joined the Department of Microbiology of theUniversity of Washington as head of the department.^[4][6]

Outside of academia, Greenberg was an associate editor of theAnnual Review of Microbiology from 1991 to 2001.^[7]

Before the 1960s and 70s,bacteria were thought to be independent organisms that do not communicate with one another.^[8][9] The first indication of inter-bacterial communication was reported by Alexander Tomasz in 1965, who foundStreptococcus pneumoniae secretes a substance that allow otherS. pneumoniae to take up foreignDNA.^[10] Then in 1970,John Woodland Hastings discovered thatAliivibrio fischeri produced light and becamebioluminescent under highcelldensity but not in diluted concentration, a phenomenon known asautoinduction.^[11] The molecule thatA. fischeri secretes for autoinduction is called anautoinducer, which was not identified until 1981.

In 1985, Greenberg reported that, instead of a complex mechanism, the autoinducer simplypassively diffuses from one bacterial cell to another,^[12] revealing one of the mechanisms of bacterial communication.

He switched course after moving to theUniversity of Iowa, focusing on the luxRprotein inA. fischeri; the protein is atranscription factor activated by the autoinducer.^[13] Research by Greenberg's team confirmed theC-terminus of luxR bindsDNA^[14] while itsN-terminus binds the autoinducer.^[15]

In a seminal article in 1994, Greenberg, together with Claiborne (Clay) Fuqua and Stephen Winans, at the time both fromCornell University, coined the termquorum sensing to describe the behavior of autoinduced bioluminescence inA. fischeri and other bacterialspecies.^[16]

Greenberg has also branched out fromA. fischeri, collaborating withBarbara Iglewski at theUniversity of Rochester to study quorum sensing inPseudomonas aeruginosa, theinfection of which is the primary cause of death incystic fibrosis patients. The collaboration stemmed from Iglewski's discovery in 1991 of aP. aeruginosagene coding for a transcription factor protein that controls the expression of genes which, in turn, control itsvirulence. The closest relative of the transcription factor, in terms of protein sequence, was the luxR protein.^[17] This partnership led to the discovery of three quorum sensing signaling pathways inP. aeruginosa.^[18]

His research in quorum sensing led Greenberg to study the phenomenon ofbiofilm, which is a high-density cluster ofbacteria that attaches to each other and to surfaces and is embedded in anextracellular matrix. Notably, bacteria in biofilms are more resistant toantibiotics than their free-living counterparts.^[13] In 1998, Greenberg, Iglewski, andJ. William Costerton reported the link between quorum-sensing genes and biofilm formation, the first publication to show agenetic factor in biofilm structure.^[19] Over the next years, he kept studying biofilms and their effects on diseases, discovering thatlungs ofcystic fibrosis patients are infected with biofilms,^[20] and thatiron is required forP. aeruginosa biofilm formation.^[21]

Greenberg met his wife,Caroline Harwood, during hisPhD years at theUniversity of Massachusetts Amherst.^[4] They started dating when he was apostdoctoral researcher atHarvard University, and were married in 1984.^[2] Harwood is currently also aprofessor at the Department ofMicrobiology of theUniversity of WashingtonSchool of Medicine.^[22]

• Fellow of theAmerican Association for the Advancement of Science (1989)^[23]
• Member of theAmerican Academy of Arts and Sciences (2002)^[24]
• Member of theNational Academy of Sciences (2004)^[25]
• Shaw Prize in Life Science and Medicine (2015)^[26]
• Princess of Asturias Award for Technical and Scientific Research (2023)^[3]
• Canada Gairdner International Award (2023)^[27]

• 1948 births
• Living people
• American microbiologists
• Everett Community College alumni
• Cornell University faculty
• University of Iowa faculty
• University of Washington faculty
• Western Washington University alumni
• University of Iowa alumni
• University of Massachusetts Amherst alumni
• Fellows of the American Academy of Arts and Sciences
• Fellows of the American Association for the Advancement of Science
• Members of the United States National Academy of Sciences
• Scientists from New York City

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