GOOD EVENING AND WELCOME. THANK YOU FOR ATTENDING TODAY'S PATTEN LECTURE, FEATURING PROFESSOR BONNIE BASSLER OF PRINCETON UNIVERSITY. MY NAME IS BABAK SERADJEH I'M A FACULTY IN THE PHYSICS DEPARTMENT HERE AT I.U. AND A MEMBER OF THE PATTEN COMMITTEE. BEFORE WE TELL YOU MORE ABOUT OUR EXTRAORDINARY PATTEN LECTURER TONIGHT, I WOULD LIKE TO TELL YOU A LITTLE BIT ABOUT MR. PATTEN AND THE LEGACY OF HIS BEQUEST. 1931, WILLIAM T. PATTEN OF INDIANAPOLIS, WHO RECEIVED HIS BACHELOR'S DEGREE IN HISTORY IN 1893, MADE A GIFT OF ABOUT $150,000 TO ESTABLISH THE PATTEN FOUNDATION AT HIS ALMA MATER. AT THE TIME, IT WAS THE SINGLE LARGEST GIFT EVER PLEDGED TO THE BLOOMINGTON CAMPUS. UNDER THE TERMS OF THIS GIFT, WHICH BECAME AVAILABLE UPON HIS DEATH IN 1936, A VISITING PROFESSOR WAS CHOSEN EACH YEAR ORIGINALLY TO BE IN RESIDENCE FOR AT LEAST TWO MONTHS OF THE YEAR, HERE ON CAMPUS. THE PURPOSE OF THIS APPOINTMENT WAS TO PROVIDE MEMBERS OF THE UNIVERSITY, STUDENTS, FACULTY AND STAFF, THE PRIVILEGE OF PERSONAL ACQUAINTANCE WITH THE VISITING PROFESSOR. WHILE THOSE TERMS HAVE CHANGED OVER THE YEARS, WE NOW TYPICALLY HAVE TWO PATTEN LECTURERS, WHO SPEND A WEEK ON CAMPUS EACH YEAR, THE SPIRIT REMAINS THE SAME. WHAT IS REMARKABLE IS THAT NEARLY A CENTURY LATER, WE ALL STILL ENJOY THE BENEFITS OF MR. PATTEN'S GENEROSITY AND COMMITMENT TO THE ENRICHMENT OF OUR CAMPUS. THE PATTEN LECTURES CONTINUE TO REFLECT HIS COMMITMENT TO INDIANA EDUCATION. CHOSEN BY A CAMPUS-WIDE FACULTY COMMITTEE, PATTEN LECTURERS HAVE REPRESENTED OVER 50 ACADEMIC DEPARTMENTS AND PROGRAMS. SINCE THE FIRST PATTEN LECTURE BY THE GERMAN BUSINESS ECONOMIST ALFRED MANIS IN 1937, MORE THAN 200 WORLD-RENOWNED SCHOLARS HAVE BEEN LECTURED HERE. NOTED SPECIALISTS IN THEIR FIELDS, SPEAKERS HAVE BEEN CHOSEN FOR THEIR ABILITY TO CONVEY THE SIGNIFICANCE OF THEIR WORK TO A GENERAL AUDIENCE. LECTURERS STAY ON CAMPUS FOR ONE ACADEMIC WEEK, DURING WHICH TIME THEY INTERACT WITH THE FACULTY, STUDENTS AND CLASSES AND INFORMAL GATHERINGS AND DELIVER TWO PUBLIC LECTURES. WE ARE THRILLED THAT PROFESSOR BONNIE BASSLER IS AS A 2025-26 PATTEN LECTURE. SPECIAL THANKS FOR ENABLING SPECIAL BASSLER'S VISIT GO TO HER NOMINATORS PROFESSOR JULIA VAN KESSEL AND CLAY FURQUA. THE MANY DEPARTMENTS AND UNITS SUPPORTING HER VISITS ARE IN THE COLLEGE OF ARTS AND SCIENCE, THE DEPARTMENT OF BIOLOGY, CHEMISTRY, MOLECULAR AND CELLULAR BIOCHEMISTRY, PHYSICS AND PSYCHOLOGICAL AND BRAIN SCIENCES, AS WELL AS THE LUDDY SCHOOL OF INFORMATICS COMPUTING AND ENGINEERING. THANKS ALSO GO TO THE INTERIM PROVOST JOHN CIORCIARI, THE COX RESEARCH SCHOLARS PROGRAM, THE EMERITI HOUSE. TO INTRODUCE OUR ESTEEMED GUEST TONIGHT, I'M HAPPY TO PRESENT CLAY FURQUA FROM BIOLOGY. THANK YOU. [ APPLAUSE ] >> Clay Furqua: THANK YOU, BABAK. WHAT A TURNOUT. GREAT. THANKS, EVERYONE, FOR COMING. IT'S MY PLEASURE TO BE ABLE TO INTRODUCE BONNIE BASSLER FOR THIS PATTEN LECTURE, THE SECOND PATTEN LECTURE. BODY IS THE SQUIBB PROFESSOR OF MOLECULAR BIOLOGY AT PRINCETON UNIVERSITY AND HAS BEEN SO KIND TO PROVIDE TWO PRESENTATIONS FOR US THROUGH THIS MECHANISM. JULIA VAN KESSEL AND I HAVE BEEN REALLY HAPPY TO HAVE BONNIE VISIT TO I.U. THROUGH THIS SERIES AND WITH THE HELP, QUITE A BIT OF HELP FROM INDERMOHAN VIRK AND HER STAFF AT THE PATTEN LECTURE COMMITTEE OR THE OTHER MEMBERS OF THE COMMITTEE, THAT IS. I DON'T KNOW IF THEY ARE REALLY HER STAFF OR JUST CONTRIBUTORS. [ CHUCKLES ] AS MANY OF YOU KNOW AND SOME OF YOU HEARD LAST NIGHT, BONNIE IS AN AMAZING ACADEMIC SCIENTIST WITH ALL SORTS OF ACCOLADES AND DISTINCTION, SOME OF WHICH JULIA MENTIONED IN HER INTRODUCTION FOR HER. JUST ABOUT EVERY AWARD YOU COULD GIVE SOMEONE IN THE FIELD OF MICROBIOLOGY AND SCIENCE WRIT LARGE, BONNIE HAS EARNED. SHE'S ALSO BEEN A REALLY TIRELESS ADVOCATE FOR SCIENCE IN GENERAL, SERVING AS PRESIDENT OF THE AMERICAN SOCIETY FOR MICROBIOLOGY DURING A REALLY KEY PERIOD. SHE ALSO SERVED ON PRESIDENT OBAMA'S NATIONAL SCIENCE BOARD, AMONGST MANY OTHER THINGS. SO RATHER THAN GO THROUGH THIS VAST BODY OF INFORMATION WHICH IS ALL ON HER WIKIPEDIA PAGE. I WILL TELL YOU A LITTLE OF MY OWN PERSPECTIVE ON BONNIE AND HER WORK AND PLEASE HUMOR ME, BONNIE. BONNIE PURSUED HER GRADUATE STUDIES AT JOHNS HOPKINS WITH -- SHE HAD FINISHED HER UNDER GRAD FROM UCSD IN CALIFORNIA. SHE DID HER Ph.D. WITH SAL ROSEMAN AT JOHNS HOPKINS AND STARTED HER LIFELONG FASCINATION WITH BACTERIA. SHE MAY NOT HAVE KNOWN, IT I DON'T KNOW IF SHE STILL KNOWS IT BUT WE OVERLAPPED IN BALTIMORE DURING THAT TIME. I WAS AT THE CENTER OF MARINE BIOTECHNOLOGY IN BALTIMORE AS PART OF MY GRADUATE TRAINING AT COLLEGE PARK IN -- AT MARYLAND. UNIVERSITY OF MARYLAND. WE DIDN'T KNOW EACH OTHER MUCH AT THAT POINT, EVEN THOUGH THEY BOTH WORKED ON OBSCURE AND ESOTERIC MARINE BACTERIA. I REALLY FIRST BECAME AWARE OF BONNIE'S WORK WHEN I WAS A POSTDOC AT CORNELL AND RESEARCHING A TERRESTRIAL BACTERIA, THAT WE STILL WORK ON, AND WE DISCOVERED THAT IT USED IN A SIMILAR MECHANISM AS THE VIBRIOS TO CONTROL THEIR BIOLUMINESCENT IT USED IT TO CONTROL HORIZONTAL GENE TRANSFER. SO BONNIE, AT ABOUT THAT TIME WAS A POSTDOC AT THE AGOURON INSTITUTE WITH MIKE SILVERMAN WHO HAD DONE SOME FIRST MOLECULAR ON THE QUORUM SENSING IN THE VIBRIOS. SO BONNIE WAS BUSY DISSECTING THE BIOLUMINESCENT IN MARINE VIBRIOS AND DID SOME AMAZINGLY CLEVER AND SYSTEMIC GENETICS ON THAT SYSTEM AND I WOULD SAY SHE TOTALLY BLEW OPEN THE UNDERSTANDING OF THAT REGULATION, BY TAKING THIS UNBIASED GENETIC APPROACH, AND SHE REALLY REWROTE THE UNDERSTANDING OF THAT SYSTEM. AND SET THE STANDARD IN THESE THREE LANDMARK PAPERS IN 1993 THROUGH 1994. I CAN STILL REMEMBER I WAS WORKING ON SIMILAR AREAS, NOT QUITE THE SAME THING, BUT I WAS ACROSS THE HILL FROM CORNELL AT ITHACA COLLEGE, WORKING WITH THIS IRASCIBLE AND ENERGETIC CHEMIST, ANATOL EBERHARD. HE WAS A REAL CHARACTER BUT HE WENT TO A MEETING IN HAWAII, A VIBRIO MEETING IN OHIO AND BONNIE GAVE A TALK AS A POSTDOC. AND HE CAME BACK AND SAID BONNIE BASSLER IS REWRITING THE BOOK ON VIBRIO. AND NOT ONLY ANATOL COULD HAVE PREDICTED HOW RIGHT HE WAS AND I HAVE BEEN ABLE TO SORT OF WITNESS THE DEVELOPMENT OF A LOT OF THIS WORK AND IT'S REALLY BEEN A PLEASURE. BONNIE WAS HIRED OUT OF HER POSTDOC TO PRINCETON WHERE SHE'S BEEN EVER SINCE. AS RECENTLY AS THIS YEAR, SERVING AS THE CHAIR OF THE DEPARTMENT OF MOLECULAR BIOLOGY FOR QUITE SOME YEARS. ASTOUNDINGLY. SHE AND HER MANY TRAINEES AND COLLABORATORS AT PRINCETON HAVE GONE ON TO EXPAND THE UNDERSTANDING OF THESE SYSTEMS AND THE MANY WAYS IN WHICH BACTERIA CAN COMMUNICATE WITH EACH OTHER, DOWN TO THE MOLECULAR AND ATOMIC LEVEL, AND THEY HAVE DEVELOPED LOTS OF INNOVATIVE STRATEGIES TO TARGET THESE PROCESSES. AND THE WORK -- I WILL GO AHEAD AND EMBARRASS BONNIE, IT'S BEEN VERY -- IT'S BEEN BRILLIANT. MANY HIGH IMPACT PAPERS AND ARTICLES, REALLY RIGOROUS SCIENCE AND EXPERIMENTATION, LOTS OF INSIGHTS AND BEAUTIFUL WRITING. AND LAST NIGHT'S PRESENTATION, BONNIE GAVE ME SOME OF THE CREDIT FOR ESTABLISHING THE NAME QUORUM SENSING. WHICH PERHAPS IT'S TRUE THAT I WOULD GET SOME PORTION OF THAT. I WOULD ARGUE THAT BONNIE AND HER LAB HAVE DONE THE MOST OF ANYONE TO FILL THIS TERMINOLOGY WITH MEANING AND MECHANISM. AND THIS NOW INCLUDES TRAINEES WHO HAVE TRAINED WITH BONNIE AND GONE ON TO BUILD THEIR OWN PROGRAMS LIKE OUR OWN JULIA VAN KESSEL THAT'S CONTINUING THIS WORK. AND THERE'S NO SIGN THAT BONNIE IS LETTING UP AND CERTAINLY THE PEOPLE THAT HAVE BEEN TRAINED WITH HER ARE NOT LETTING UP. EVEN THIS PAST YEAR, PUBLISHING THIS AMAZING SERIES OF STUDIES THAT STILL BREAK NEW GROUND. SO I'M STILL BEARING WITNESS TO THIS ASTOUNDING WORK AND IT'S REALLY, REALLY FUN. SO BONNIE, I WILL STOP EMBARRASSING YOU AND I WILL LET YOU TELL US ABOUT THE LATEST IN THIS FANTASTIC SCIENTIFIC STORY. [ APPLAUSE ] >> Bonnie Bassler: I'M NOT USUALLY SPEECHLESS. IT DOESN'T COME UP. THE COMPUTER IS NOT ON. WELL, I DON'T MIND LOOKING AT MYSELF ALL NIGHT, BUT -- OKAY. GOOD. OKAY. ANYWAY. THAT WAS SO HEART FELT AND SWEET, AND MOSTLY NOT TRUE. BUT ANYWAY, THAT'S THE MOST GENEROUS AND SWEETEST INTRODUCTION EVER. AND SO I HOPE I CAN BE THAT PERSON, SOMETHING LIKE THAT PERSON TONIGHT. ANYWAY, IT'S REALLY LOVELY TO BE BACK TONIGHT AND TO GET TO GIVE YOU THE ADULT VERSION, IF YOU WERE HERE LAST NIGHT, YOU WILL GET THE ADULT VERSION OF SOME OF THE NEWER SCIENCE AND MUCH MORE TECHNICAL THAN I TOLD YOU ABOUT LAST NIGHT. I STILL WORK ON QUORUM SENSING 24 HOURS LATER, BUT THIS TALK I WILL TELL YOU ABOUT SOME OF THE REALLY NEW STUFF WE'RE DOING IN THE LAB RIGHT NOW. FOR THOSE OF YOU WHO WERE HERE LAST NIGHT, SINCE I STILL WORK ON QUORUM SENSING, THE FIRST SLIDE IS ONE YOU HAVE ALREADY SEEN BUT THEN DON'T LEAVE BECAUSE I WILL DO MORE. ANYWAY, SO DIDN'T'S GOAL, I HOPE YOU ALREADY BELIEVE THAT BACTERIA CAN COMMUNICATE AND WORK AS GROUPS FROM LAST NIGHT. TONIGHT, I WANT TO TRY TO SHOW YOU THE QUORUM SENSING GOES BEYOND BACTERIA, THAT THE EUKARYOTES AND THE VIRUSES ARE ALSO PARTICIPATING IN THESE CHEMICAL CONVERSATIONS AND WHAT I HOPE YOU WILL SEE IS THAT THERE'S A NEW HORIZON FOR THIS FIELD. I FEEL LIKE A MONTY PYTHON MOVIE, WE'RE NOT DONE YET. AND I HOPE YOU SEE WHERE MY LAB IS REALLY GOING NOW. AND LAST NIGHT WAS THE BACKGROUND FOR ALL OF THAT. SO TO GET INTO IT, FOR ANYBODY WHO WASN'T HERE LAST NIGHT, WHAT MY LAB IS ALWAYS TRYING TO DO IS TO FIGURE OUT HOW BACTERIA GET ANY BANG FOR THEIR BUCK. THERE'S THESE ITTY-BITTY ANCIENT, THE WORLD'S MOST ANCIENT CRITTERS. THEY DO ALL OF THESE HORRIBLE THINGS LIKE CAUSE DISEASE. THEY DO ALL OF THESE MAGNIFICENT THINGS LIKE KEEPING US ALIVE, THE SAME WITH PLANTS AND ANIMALS. WE KNOW THAT THEY DO THAT. MY LAB, WE ARE NOT INTERESTED IN THE FACT THAT THEY DO THOSE THINGS. WE ARE INTERESTED IN HOW THEY DO THOSE THINGS. WHAT WE WANT TO UNDERSTAND IS HOW CAN THESE TINY ANCIENT ORGANISMS CARRY OUT THESE ENORMOUS TASKS. AND SO THE WAY WE THINK THAT BACTERIA GET THEIR POWER IS BY COMMUNICATING WITH THIS CHEMICAL LANGUAGE WHICH CLAY THOUGHT THE NAME OF, THAT WE CALL QUORUM SENSING, RIGHT? AND SO THE WAY IT WORKS IS THE BACTERIA MUST DISTINGUISH TIMES WHEN THEY ARE IN LONE AND WHEN THEY ARE IN COMMUNICATE, AND BEHAVE DIFFERENTLY UNDER THOSE TWO SITUATIONS. THEY COMMUNICATE WITH THESE CHEMICAL MOLECULES THAT WE CALL AUTOINDUCERS. AND SO WHEN BACTERIA ARE AT LOW CELL DENSITY. WHEN THEY ARE ALONE, THEY WANT TO HAVE THE PROGRAM GENE EXPRESSION GOING THAT'S GOOD FOR ACTING AS AN INDIVIDUAL. THEY CARRY OUT SOME SUBSET OF THE TASKS THAT THEY ARE CAPABLE OF DOING BUT AMONG THE THINGS THEY DO IS THAT THEY MAKE AND RELEASE THESE -- CAN YOU SEE THAT? NO? OKAY. THEY MAKE AND RELEASE THESE SMALL MOLECULES CALLED AUTOINDUCER DEPICTED BY THE RED TRIANGLES AND WHEN THEY DIFFUSE AWAY, THE BACTERIA CAN'T DETECT THEM. THEY ACT AS INDIVIDUAL AND SO THEY CARRY OUT THESE BEHAVIORS THAT ONE BACTERIUM CAN SUCCESSFULLY MANAGE. OKAY. BUT THEN AS THE BACTERIA GROW IN NUMBER, SINCE ALL THE BACTERIA ARE MAKING A SHARE OF THE MOLECULES, RIGHT THE MORE CELLS THERE ARE, THE MORE OF THESE MOLECULES THERE ARE AROUND THE CELL. AND WHEN THE MOLECULES ACCUMULATE TO A CRITICAL AMOUNT THE BACTERIA DETECT IT AND THEY INFER FROM THIS DETECTION EVENT THAT THEY MUST HAVE NEIGHBORS AROUND. AND SO IN UNISON, ALL THE BACTERIA CHANGE THEIR GENE EXPRESSIONS WHICH CHANGES THE REPERTOIRE OF PROTEINS THAT THEY MAKE AND ALLOWS THEM TO CHANGE BEHAVIOR. IT TAKES LOTS OF BACTERIA ACTING TOGETHER TO MAKE THE TASK SUCCESSFUL. WE KNOW THAT QUORUM SENSING IS THE NORM IN THE BACTERIAL WORLD. THERE ARE TENS OF THOUSANDS OF CASES OF SPECIES OF BACTERIA THAT HAVE QUORUM SENSING CIRCUITS, RIGHT, AND SO IT'S A BIG DEAL AND IT WAS AN EARLY STEP IN EVOLUTION WHEN COLLECTIVE BEHAVIORS EVOLVED ON THIS EARTH, RIGHT, AND THE BACTERIA, YOU KNOW, INVENTED THAT, IF YOU WILL. IN EVERY BACTERIUM, THAT'S BEEN STUDIED. HUNDREDS OF GENES ARE CONTROLLED BY THESE QUORUM SENSING CIRCUITS AND IT'S A STEP-BY-STEP PRACTICE WHERE THEY TURN ON ALL OF THESE GENES AND THEY CARRY OUT THE GROUP TASKS. I TALKED ABOUT BIOFILM INFORMATION, AND HOW THEY SIT ON SURFACES AND VIRULENCE, AND LAST NIGHT'S TALK WAS MUCH MORE ABOUT APPLICATION IF WE COULD INTERFERE WITH QUORUM SENSING ON DEMAND AND MAYBE WE COULD STOP MAKING BIOFILMS AND STOP THEM FROM EXPERIENCING THEIR VIRULENCE FACTORS AND MAKE NEW KINDS OF MEDICINES OR PRODUCTS FOR SOCIETY. WHAT YOU KNOW FROM LAST NIGHT AND WHAT YOU KNOW FROM WHAT CLAY TOLD YOU ABOUT, ALL OF THIS STARTED IN THE OBSCURE BIOLUMINESCENT. THE ORIGINAL BEHAVIOR THAT WE UNDERSTOOD WAS A QUORUM SENSING BEHAVIOR WAS LIGHT PRODUCTION. RIGHT? AND SO THAT IS FROM THESE HARMLESS MARINE BACTERIA, THAT HAD THIS PROPERTY. AND SO USING THEM AS OUR MODEL, WE BEGAN TO LEARN WHAT SOME OF THE CHEMICALS ARE THAT THESE BACTERIA TALK WITH. SO ON THIS NEXT SLIDE, I'M GOING TO SHOW YOU THE CHEMICALS THAT THIS ORIGINAL BIOLUMINESCENT, VIBRIO HARVEYI, THEY USE DIFFERENT SETS OF THE MOLECULES BUT THE PRINCIPLES I WILL TELL YOU ABOUT IN THE NEXT SLIDE SEEM TO TRANSCEND ALL QUORUM SENSING SYSTEMS. SO WHAT WE THINK NOW IS THAT IN ORDER FOR BACTERIA TO HAVE A PROPER QUORUM SENSING CONVERSATION, THERE ARE AT LEAST THREE MOLECULES INVOLVED AND SO THE TOP ONE IS ACTUALLY THE ONE THAT ANATOL EBERHARD FIGURED OUT. THE TOP ONE IS A RING WITH A TAIL ON IT. AND THE WHAT WE UNDERSTAND ABOUT THIS KIND OF MOLECULE IS THAT, ONE, AND ONLY ONE SPECIES OF BACTERIA MAKES THIS MOLECULE. SO WHAT WE THINK THEN IS THIS IS FOR INTRASPECIES COMMUNICATION. THIS IS HOW I COUNT MY SIBLINGS AND KNOW HOW MANY OF MY KIN ARE AROUND. THE SECOND MOLECULE, THE FATTY ACID THAT WE DISCOVERED, ALL VIBRIO MAKE THAT. AND NO BACTERIUM, EXCEPT A VIBRIO MAKE THAT MOLECULE. SO WE THINK THAT'S THE LANGUAGE OF THE GENUS. FIRST ONE SAYS YOU ARE MY TWIN. THE SECOND MOLECULE SAYS YOU ARE MY COUSIN. AND THEN THE THIRD MOLECULE THAT WE DISCOVERED ON THE BOTTOM IS A UNIVERSAL MOLECULE THAT AT LEAST HALF OF ALL BACTERIA THAT WE KNOW ABOUT MAKE THIS MOLECULE. THEY ALL MAKE THE IDENTICAL MOLECULE. IT'S ONE MOLECULE. IT'S THE SAME IN EVERY SPECIES. AND SO WE THINK THERE'S NO SPECIES INFORMATION IN THAT MOLECULE. WE THINK THAT'S FOR TALKING ACROSS SPECIES BOUNDARIES. RIGHT? SO NOW WHAT WE UNDERSTAND ABOUT QUORUM SENSING IS THAT WHAT WE THINK THE BACTERIA ARE DOING, THEY ARE CERTAINLY COUNTING. THEY ARE COUNTING DO I HAVE THE -- THEY ARE TAKING A CENSUS. DO I HAVE THE RIGHT NUMBER OF BACTERIA THAT WE CAN CARRY OUT A TASK. WHAT WE THINK THE FIRST THING THEY DO IS MEASURE THEIR ENVIRONMENT FOR THE QUORUM SENSING MOLECULES AND THEY ASK AM I ALONE OR AM I IN A GROUP AND THAT STARTS TO TELL THEM WHAT GENES TO TURN ON AND OFF. THE MORE SOPHISTICATED COMPUTATION THAT THEY DO, THEY MEASURE THE RATIO OF THOSE THREE MOLECULES, RIGHT? AND SO WHAT WE THINK THEY ARE TRYING TO DO, THEY ARE ASKING IN THIS GROUP, IS IT MOSTLY MY KIN? LIKE, DO I SEE THE SELF SIGNAL OR IS IT MOSTLY MY COUSIN OR IS IT MOSTLY THE ENEMY. THEY MEASURE THE RATIOS OF THE THREE MOLECULES, AND THEY UNDERSTAND SOMETHING ABOUT HOW MANY CELLS ARE AROUND THEM, BUT ALSO SOMETHING ABOUT WHO THOSE CELLS ARE AND WHETHER OR NOT THOSE CELLS ARE CLOSELY OR DISTANTLY RELATED TO ME. AND THEN THE BACTERIA CHANGE WHAT GENES THEY TURN ON AND OFF, BASED ON WHETHER THEY ARE SURROUNDED BY THEIR KIN, THEY MAKE PUBLIC GOODS, THEY MAKE ALL OF THESE GOODIES OR SURROUNDED BY THE ENEMIES AND THEN THEY COMPETE AND TRY TO KILL EACH OTHER. WHAT WE GET ABOUT THE QUORUM SENSING MOLECULES THEY ENCODE ABOUT SOMETHING ABOUT THE NUMBER OF CELLS BUT THEY ALSO ENCODE IN THOSE LITTLE MOLECULES THEY ENCODE INFORMATION ABOUT HOW CLOSELY OR DISTANTLY I AM RELATED TO MY NEIGHBOR. AND THE BACTERIA ACTS AS THAT INFORMATION, AND THEY ACT -- ACCESS THAT INFORMATION AND THEY ACT ON IT ROBUSTLY APPARENTLY. THAT'S WHAT WE NOW THINK QUORUM SENSING IS. AND TODAY WHAT I WANT TO DO IN MY LOVE AFFAIR WITH VIBRIOS THAT I'M APPARENTLY HAVING. IT'S SORT OF A LOVE/HATE RELATIONSHIP, I HAVE TO ADMIT. NOW THIS BEAUTIFUL BACTERIUM THAT I TALKED ABOUT LAST NIGHT BUT THE REALLY HARMFUL CONVERSATION. SO VIBRIO CHOLERA. IT'S A QUORUM SENSING BACTERIA. BUT IT CAUSES DISEASE. AND SO MAYBE YOU KNOW THAT VIBRIO CHOLERAE, YOU GET IT BY DRINKING OR EATING CONTAMINATED FOOD OR WATER. AND SO QUORUM SENSING CONTROLS VIRULENCE AND CHOLERA. AND SO THE WAY IT WORKS IS WHEN CHOLERA GETS INTO THE HUMAN INTESTINE, IT COMES IN AT LOW CELL DENSITY. CHOLERA IS A REALLY INSIDIOUS, PERSNICKETY PATHOGEN. IT GETS IN AND GETS OUT AT HIGH NUMBERS TO INFECT THE NEXT PATIENT. IT SORT OF COMES IN GUNS LOADED. IT'S MAKING A BIOFILM. IT'S HIGHLY VIRULENT AND SPEWING OUT THE TOXINS AND THAT'S HOW IT GETS A TOE HOLD IN THE HUMAN INTESTINES. BIOFILM IS ON AND VIRULENCE EXPRESSION IS ON. THEN AS THE BACTERIA GROW IN THE INTESTINE AND QUORUM SENSING KICKS IN. SO WHEN THEY GET TO HIGH CELL NUMBER, WHICH HAPPENS IN THE INTESTINE, THEY DETECT THE AUTOINDUCERS AND THAT FLIPS A SWITCH. WHAT THEY DO, THEY TURN OFF VIRULENCE FACTOR PRODUCTION. THEY TURN OFF BIOFILM PRODUCTION. THEY TURN ON A PROTEASE THAT CUTS THEM OFF THE INTESTINAL EPITHELIA CELLS AND THEY BECOME MODAL AND THEY GET OUT AT HIGH NUMBERS IN THIS TERRIBLE DIARRHEAL DISEASE. AND IT'S ALL ABOUT TRANSMISSION AND INFECTING THE NEXT PATIENT AND QUORUM SENSING CONTROLS THOSE LIFE-CHANGING SWITCHES. CHOLERA HAS TO DO THOSE SWITCHES REPEATEDLY IN THE ENVIRONMENT AND IN THE HOST. SO IF CHOLERA DOESN'T HAVE THE QUORUM SENSING APPARATUS, IT CAN'T DO THAT, IT'S NOT A PATHOGEN BECAUSE THE LIFESTYLE CHANGES ARE ESSENTIAL. OKAY? SO THAT'S HOW IT WORKS IN TERMS OF THE DISEASE. AND WE HAVE WORKED OUT MANY -- OR I HOPE MANY OF THE COMPONENTS THAT ARE INVOLVED IN THIS QUORUM SENSING CIRCUIT. NOW GOING A LITTLE BIT DEEPER INTO THE SYSTEM, THE WAY IT WORKS IS THAT CHOLERA USES TWO OF THREE SENSING THAT I SHOWED YOU. AT LOW DENSITY WHEN CHOLERA GETS INTO THE HOST, IT HAS RECEPTORS ON THE MEMBRANE. SO UNDER THAT CONDITION, CHOLERA TURNS ON A SET OF SMALL RNAs WE CALL THEM QRR FOR QUORUM REGULATORY RNAs. THEY ARE MICRO RNAs. AND SO THOSE SMALL RNAs REGULATE MESSENGER RNAs. AND THESE SMALL RNAs ALLOW BIOFILM INFORMATION TO HAPPEN AND VIRULENCE EXPRESSION TO HAPPEN. THAT'S WHAT I JUST TOLD YOU ON THE LAST SLIDE. BUT THEN AS THE BACTERIA GROW IN THE INTESTINE AND THE AUTOINDUCERS ACCUMULATE AND THEY HAVE NAMED CIA ONE AND CI2, HERE'S THE STRUCTURES. THE AUTOINDUCER ACCUMULATE AND THEY SLOT INTO THEIR RECEPTORS AND THEN CHOLERA TURNS OFF THOSE SMALL RNAs AND THAT REPRESSES BIOFILM INFORMATION, REPRESSES VIRULENCE FACTOR EXPRESSION AND IT ALLOWS CHOLERA TO DISPENSE. THAT TRACKS WITH WHAT I JUST SHOWED YOU ON THE LAST SLIDE AND THOSE ARE THE PROTEINS AND THE COMPONENTS INVOLVED IN THAT SYSTEM. SO WE DISCOVERED THAT STUFF AND HAVE BEEN WORKING ON IT YEARS AGO AND WE'RE ALWAYS DOING THESE SCREENS IN THE LAB TO THINK ABOUT THAT CIRCUIT AND THE GENES THAT ARE CONTROLLED AND WHAT CHOLERA IS DOING, YOU KNOW, THAT HAS TO DO WITH QUORUM SENSING, AND AROUND THE TIME WE HAD ALL OF THESE COMPONENTS A FANTASTIC POSTDOC KAI PAPENFORT JOINED THE LAB. HE LOOKS AT THE GENES CONTROLLED BY QUORUM SENSING. AND WHAT KAI SURPRISINGLY DISCOVERED WAS ANOTHER SMALL RNA AND ANOTHER PROTEIN THAT CONTROLLED EXACTLY THE SAME GENES. SO KAI FOUND A PROTEIN THAT HE CALLS -- AND THIS IS A CYTOPLASMIC. SO HE CALLS IT VQMA, THIS TRANSCRIPTION FACTOR BINDS DNA AND TURNS ON ANOTHER RNA, CALLED DQRNA, FOR RNA AND THAT SHUTS DOWN THE BIOFILM INFORMATION AND VIRULENCE. THE LOGIC CIRCUIT. AND IT WAS TURNING THE BIOFILM GENES AND THE VIRULENCE GENES OFF. SO WORKING EXACTLY LIKE THE CIRCUITS THAT I HAD ALREADY TOLD YOU ABOUT THAT WE HAD DISCOVERED AND WHAT WAS FUNNY ABOUT KAI'S FINDING, WAS THAT THAT VQMA PROTEIN WAS ALWAYS MADE. IT'S ALWAYS MADE IN THE CELL. NO MATTER WHAT WE DID, IT'S ALWAYS AROUND. IT ONLY TURNED ON THAT SMALL RNA AT HIGH CELL DENSITY. SO IF THE PROTEIN IS NOT CHANGING ITS AMOUNT, ITS ACTIVITY HAD TO BE CHANGING. SO AT HIGH CELL DENSITY, SOMEHOW THAT DENSITY, VQMA GOT ACTIVATED TO TURN ON THAT SMALL RNA. WE WONDERED WHAT IS TURNING ON VQMA. SO IN MY LAB, IF SOMETHING HAPPENED AT HIGH CELL DENSITY, THAT'S QUORUM SENSING 101, IT'S DING, DING, DING, QUORUM SENSING, THAT'S THE ONLY THING WE KNOW WHAT TO DO. WE ALREADY KNEW THE AUTOINDUCERS. WE CAN MAKE THOSE SYNTHETICALLY. WE HAVE BUCKETS OF THOSE AND WE HAD MUTANTS THAT DIDN'T MAKE THE FIRST AUTOINDUCER OR THE SECOND AUTOINDUCER AND WE HAD A BATTERY OF REAGENTS THAT WE COULD TEST TO FIGURE OUT HOW THIS NEW PROTEIN, VQMA AND THE NEW SMALL RNA ARE FEEDING INTO PRESUMABLY OUR QUORUM SENSING SYSTEM. WE ADDED ONE AUTOINDUCER AND BOTH AUTOINDUCERS AND WE KNOCKED ONE OUT AND THEN KNOCKED THEM ALL OUT AND NOTHING CHANGED THAT SYSTEM. AND SO WHAT WE HAD TO INFER FROM THOSE FAILED EXPERIMENTS, AIR QUOTES FAILED EXPERIMENTS WHAT THAT THERE HAD TO BE SOME AUTOINDUCER THAT WAS MISSING AND WE COULD PROVE THAT THAT WAS CORRECT BECAUSE IF WE JUST GREW UP CELLS AND TOOK THE CELL-FREE CULTURE FLUIDS AND SQUIRTED THEM ON, THAT SYSTEM WOULD ENGAGE. OKAY? SO AFTER ALL OF THESE MANY YEARS OF WORK, IT WAS CLEAR THERE WAS A THIRD QUORUM SENSING SYSTEM IN THIS BUG THAT WE HAD MISSED ALL OF THESE YEARS PRIOR. RIGHT? SO THEN THE SORT OF LOGIC WAS THAT AT LOW CELL DENSITY BIOFILM INFORMATION AND VIRULENCE IS ON. AND THREE AUTOINDUCERS ACCUMULATE THIS NEW ONE WITH A QUESTION MARK IS PROBABLY DETECTED BY THAT CYTOPLASMIC PROTEIN AND TURNS ON THE SMALL RNA AND ALL THREE TELL CHOLERA TIME TO LEAVE THE HOST AND INFECT SOMEONE ELSE. AND SO AT THAT POINT, IT SEEMED LIKE THERE WOULD BE ANOTHER MOLECULE AND SO KAI FLED AND WENT TO GERMANY. HE'S A PROFESSOR IN GERMANY DOING HIS OWN THING. DOING THIS. BUT ANYWAY, SO HE WENT TO GERMANY. BUT WHAT WAS LUCKY, WAS THAT AT THE TIME THAT KAI WAS FINDING THOSE -- MAKING THOSE DISCOVERIES A ROTATION STUDENT NAMED JUSTIN SELPIA, A FIRST-YEAR GRADUATE STUDENT, HE HAD A DEGREE IN ENGINEER, DECIDED TO GIVE MY LAB A TRY. HE MADE THOSE DISCOVERIES WITH KAI. THEY DID THOSE THINGS TOGETHER. KAI WAS GONE AND LEFT MORE JUSTIN STRANDED BUT -- AND HE HAD DECIDED JOIN THE LAB. AND, OF COURSE, HE WAS HOOKED ON THIS SYSTEM, BECAUSE HE HAD MADE HIS FIRST DISCOVERIES THERE. HE THOUGHT HE WOULD TAKE ON THE CHALLENGE OF FIGURING OUT WHAT THIS NEW PUNITIVE AUTOINDUCER MIGHT BE. AND THE FIRST REALLY FANTASTIC -- WE WERE FARMING AROUND, TRYING TO FIGURE OUT WHAT IS THE ACTIVITY? AND WHAT JUSTIN NOTICED, HE JUST GREW UP ALL KINDS OF BACTERIA, SPUN THEM DOWN AND TOOK THEIR SOUP AND HE COULD SEE THAT ALMOST ALL OF THEM WOULD MAKE THAT SYSTEM ENGAGE. IT SEEMED LIKE THIS ACTIVITY COULD BE ONE OF THESE GENERAL AUTOINDUCERS THAT'S WIDELY SPREAD IN THE BACTERIAL WORLD. AND WHAT HE ALSO NOTICED WAS LABORATORY E. COLI, AND SOW THOUGHT HE COULD USE -- AND SO HE THOUGHT HE COULD USE THAT OBSERVATION TO TRY TO GET IT. HERE'S THE EXPERIMENT THAT JUSTIN DECIDED TO DO. SO HE JUST TOOK REGULAR OLD LABORATORY E. COLI, AND THEN WHAT HE DID -- YOU KNOW, SO THE IDEA IS THAT E. COLI IS DONATING THIS AUTOINDUCER. IT'S MAKING THE ACTIVITY NATURALLY. AND THEN WHAT JUSTIN DID WAS HE CLONED INTO E. COLI THAT VQMA TRANSCRIPTION FACTOR THAT HE AND KAI HAD FOUND. HE BROUGHT A HIST TAG ON IT. THE IDEA WAS HE COULD PUMP UP THE PRODUCTION AND MAKE IT INTO A FACTORY OF MAKING THAT VQMA PROTEIN AND THERE'S NONE OTHER OF THIS CHOLERA NONSENSE IN THERE. THERE'S JUST ONE CHOLERA PROTEIN, THE E. COLI WOULD MAKE THE AUTOINDUCER. AND THE AUTOINDUCER WOULD BIND TO THE TRANSCRIPTION FACTOR AND THEN HE WOULD SMASH UP THE E. COLI AND THEN TAKE THE LYSATES AND IT WOULD BE BOUND TO THE NICKEL BEADS HOPEFULLY WITH THE LIGAND IN IT. WE DON'T REALLY CARE ABOUT THE PROTEIN. THE NEXT THING THAT JUSTIN DID WAS HE HEATED UP DID, NOW THE PROTEIN SHOULD BE PURIFIED. HE HEATED UP THE BEADS SO THE PROTEIN WOULD DENATURE AND THE IDEA WOULD BE THAT THE LIGAND WOULD DROP OUT AND SPIN THE BEADS OUT AND TAKE WHAT WAS LEFT OVER IN THAT FRACTION AND THEN WE COULD HOPEFULLY ONLY HAVE THAT MOLECULE THERE AND WE COULD TAKE THAT ACROSS STREET AND DO MRNA. AND THEN THERE'S A REASON THAT IT'S DRAWN AS HEX GONE AND THAT'S BECAUSE IT'S A SIX-MEMBERED RING. AND THIS IS THE AUTOINDUCER. JUSTIN FIGURED OUT THE STRUCTURE OF THIS AUTOINDUCER. IT HAS A FANCY CHEMICAL NAME. WE ABBREVIATE IT DPO. IT'S A BRAND NEW MOLECULE TO MANKIND. THEY ARE REALLY SIMPLE, REALLY SMALL, BUT EVERY ONE OF THESE -- BECAUSE THESE BACTERIA ARE METABOLICALLY INGENUOUS. THIS IS A BRAND NEW MOLECULE. WHAT YOU NEED TO KNOW IS THAT THE LEFT-HAND PART OF THE MOLECULE, THE LEFT-HAND SIDE FROM END TO END, THAT'S MADE FROM ALANINE AND THE RIGHT-HAND FROM THREONINE. AND SO THREE OF THE 20 AMINO ACIDS. TWO AMINO ACIDS ARE CONDENSED. AND WE FIGURED OUT THE ENTIRE BIOSYNTHETIC PATHWAY OF IT, BUT I'M NOT GOING TO GO THROUGH THAT. OKAY. NOW WHAT WE WOULD SAY IS INDEED -- I SHOULD TELL YOU SYNTHESIZED THE MOLECULE. HE DID THIS EXPERIMENT. THAT'S THE MOLECULE. NOW WE'RE COOKING WITH GAS AGAIN. NOW THERE'S THREE MOLECULES IN CHOLERA THAT MAKE UP THE QUORUM SENSING CIRCUIT. THE LOGIC IS THE SAME, LOW-CELL DENSITY WANTS TO BE A PATH GIN AND THE HIGH CELL IT WANTS TO ESCAPE TO THE ENVIRONMENT AND NOW THERE'S A MOLECULE THAT RUNS THROUGH THIS NEW SMALL RNA TO FURTHER REINFORCE THESE LIFESTYLE SWITCHES. SO ARE THERE ANY GRADUATE STUDENTS HERE? OH, ONE. GOOD. [ LAUGHTER ] ANYWAY, SO I'M TRYING TO STAND UP HERE AND SOUND LIKE -- ARE YOU TAPING THIS? I'M TRYING TO STAND UP HERE -- I SHOULD HAVE THOUGHT ABOUT THAT LAST NIGHT TOO IN THE MIDDLE OF THE NIGHT. I'M STANDING UP HERE TO LOOK LIKE I'M A GOOD ADVISOR AND MENTOR TO. HAVE AND JUSTIN MADE THIS DISCOVERY AND GOT THIS NICE MOLECULE AND I'M LIKE YOU'RE A FIRST-YEAR ROTATION STUDENT. WHAT NEXT? RIGHT? I WAS LIKE, WE'RE NOT DONE HERE. SO ANYWAY, SO THEN JUSTIN DECIDED TO JOIN THE LAB, ACTUALLY, RIGHT? AFTER HE GOT THIS MOLECULE. RIGHT? AND SO THEN HE HAD TO FIGURE OUT WHAT THE REST OF HIS THESIS PROJECT WAS GOING TO BE. SO HE WANTED TO STILL KEEP WORKING ON THIS SYSTEM. AND SO THIS IS WHEN JUSTIN MADE HIS SECOND, WHAT I THINK WAS SORT OF GAME CHANGER OBSERVATION FOR US. SO WE'RE TRYING TO UNDERSTAND NOW WHAT IS THE ROLE OF THIS NEW SYSTEM? RIGHT SO WE HAVE GOT THIS MOLECULE DPO AND THIS IS BROAD MAY MADE, GOBS OF BACTERIA MAKE THIS MATERIAL. THE VQMA PROTEIN, THAT TRANSCRIPTION FACTOR IS IN EVERY VIBRIO. EVERY VIBRIO HAS IT. THERE'S NEVER A STOP CONE. IT'S ALWAYS A FUNCTIONING PROTEIN BUT NO BACTERIUM, EXCEPT A VIBRIO HAS THE VQMA PROTEIN. SO THERE WAS SOMETHING WRONG WITH THIS -- THIS PATTERN, LIKE THIS ASYMMETRY, WHERE THE MOLECULE, THE PRODUCTION OF THE MOLECULE SEEMS TO BE BROADLY SPREAD BUT THE DETECTION SEEMS TO BE RESTRICTED TO VIBRIOS. NOW IT CAN BE THAT SOME BACTERIA DON'T DETECT IT. IT CAN BE THAT THEY HAVE SOME OTHER TYPE OF RECEPTOR. WE DON'T KNOW, BUT THIS WAS THE PATTERN THAT JUSTIN WAS DOING ALL OF THESE DATABASE SEARCHES TRYING TO FIGURE OUT WHAT THIS WEIRD PATTERN BETWEEN THESE TWO PARTS -- THE TWO PARTNERS MEANT. AND SO WE HAVE NOT SOLVED THAT PROBLEM YET, BUT BECAUSE HE WAS THINKING ABOUT THOSE THINGS, HE DID FIND ONE OTHER VQMA PROTEIN. THE ONLY ORGANISM, OR BACTERIA THAT HAVE VQMA ARE VIBRIOS. BUT WHEN HE EXTENDED IT BEYOND BACTERIA, HE DID FIND ANOTHER VQMA, BUT IT WASN'T IN A BACTERIUM. IT WAS ON -- I GOT TO TELL YOU THIS STUFF. IT WAS ON A VIRUS. SO JUSTIN FOUND THIS VIRUS. SO BACTERIA -- THE VIRUSES THAT INFECT BACTERIA ARE CALLED PHAGES. SO JUSTIN FOUND THIS VIRAL GENOME IN THE DATABASE. SO THIS VIRUS HAD BEEN COLLECTED IN A SAMPLE. IT'S ACTUALLY A VIBRIO VIRUS. IT LIVES IN A VIBRIO AND IT WAS COLLECTED IN A META GENOMIC SEQUENCE. AND JUSTIN SAW THIS GENOME IN THE DATABASE AND WHAT WAS WEIRD WAS ON IT IT LOOKED LIKE THIS WAS A VQMA GENE, A QUORUM SENSING GENE AND WE GOT REALLY INTERESTED IN THAT AND WE BROUGHT THE VIRUS INTO THE LAB AND WE WANTED TO STUDY IT. AND SO BEFORE I TELL YOU ABOUT THAT VQMA PROTEIN, I WANT TO DRAW YOUR ATTENTION TO THE RIGHT-HAND SIDE OF THE GENOME. ON THAT GENOME, THERE WERE GENES THAT WE COULD RECOGNIZE. SO THEY WERE CALLED C1, Q, AND LYSIS AND THESE ARE FAMOUS GENES FROM THE CLASSIC PHAGE LAMBDA. AND SO LAMBDA IS WHAT IS CALLED A TEMPERATE PHAGE AND OUR VIRUS IS ALSO A TEMPERATE PHAGE AND SO TEMPERATE PHAGES HAVE TO MAKE THE LIFESTYLE DECISIONS. THEY CAN LIVE IN TWO DIFFERENT LIFESTYLES. FIRST, THEY CAN LIVE INSIDE A HOST AND JUST BE DORMANT. THAT'S CALLED A LYSOGEN AND THEY LIVE THERE. IF THE HOST GETS IN TROUBLE, THE PHAGE WILL CHANGE FROM BEING A LYSOGEN TO THE LYTIC PHASE. IF IT FEELS S.O.S. OR DNA DAMAGE, THE PHAGE SAYS I'M OUT AND STOPS BEING A LYSOGEN AND IT KILLS ITS CURRENT HOST AND MOVES ON. THOSE GENES C1 AND Q IN LAMBDA ARE THE MEDIATORS OF THAT DECISION. AND THEN THE LYSIS GENES ARE THE ONES THAT ACTUALLY KILL THE HOST. AND SO THE WAY IT WORKS IN LAMBDA, IS, AGAIN, THE PHAGE IS MERELY LIVING ALONG AS A LYSOGEN, AND THE HOST GETS IN TROUBLE. WHEN THAT HAPPENS AND THERE'S STRESS ON THE HOST, THE C1 GENE GETS CLEAVED. AND WHEN C1 GETS CLEAVED, IT'S INACTIVATED AND THAT UNLEASHES Q AND Q TURNS ON THE LYSIS GENE AND THE PHAGES REPLICATE AND THEN THEY LEAVE THE CURRENT HOST. OKAY? AND SO THOSE ARE CLASSIC EXPERIMENTS THAT HAVE BEEN DONE 70 TO 80 YEARS AGO, JUSTIN REPEATED ALL OF THOSE EXPERIMENTS. OUR PHAGE WORKS EXACTLY LIKE LAMBDA IN TERMS OF THIS LYSIS, TEMPERATE SWITCH. WE DIDN'T NEED TO REDISCOVER ALL THE THINGS ABOUT LAMBDA. OUR INTEREST WAS OVER ON THE OTHER SIDE OF THE GENOME, IS THIS PURPLE GENE. WE'RE LIKE WHERE IS THERE A QUORUM SENSING GENE ON A PHAGE? RIGHT, QUORUM SENSING IS SUPPOSED TO BE ABOUT BACTERIA, AND WHY IS OUR QUORUM SENSING GENE ON THIS PHAGE? RIGHT? AND SO WE TRIED -- JUSTIN WANTED TO THINK OF AN EXPERIMENT TO DO, RIGHT, AND, OF COURSE, WE HAD JUST DISCOVERED DPO. WE DISCOVERED VQMA, AND WE ONLY KNEW HOW TO DO ONE EXPERIMENT AND ADD DPO AND THE AUTOINDUCER AND SEE WHAT HAPPENED. WHAT JUSTIN DID WAS HE INFECTED VIBRIO CHOLERA WITH THIS PHAGE. OKAY? AND SO NOW YOU'RE JUST LOOKING AT A REGULAR OLD GROWTH CURVE, A VIBRIO CHOLERA AND SO THAT'S JUST GROWTH OVER TIME AND NOW CHOLERA IS CARRYING THE PHAGE. AND SO CHOLERA DOESN'T CARE THAT THE PHAGE IS THERE. IT GROWS PERFECTLY FINE, BUT IF JUSTIN ADDS DPO, NOW LOOK AT THE WHITE CIRCLES ALL THE CELLS DIE. AND SO WHAT WE THINK THAT RESULT MEANS IS THAT THIS PHAGE IS AN EAVESDROPPER, RIGHT? IT IS MEASURING THE HOST-PRODUCED AUTOINDUCER AND RECOGNIZING WHEN THE HOST IS AT HIGH CELL NUMBER, AND THAT'S WHEN IT KILLS THE HOST. RIGHT? BECAUSE IF YOU THINK ABOUT IT FROM THE PHAGE'S PERSPECTIVE, IF A PHAGE IS GOING TO KILL ITS CURRENT HOST, IF THERE AREN'T OTHER HOSTS TO GET INTO, THAT PHAGE IS A GONER! SO WHEN IS A REALLY GOOD TIME TO KILL YOUR HOST? WELL, IT'S WHEN THERE'S LOTS OF OTHER HOSTS AROUND. WHEN IS THAT HAPPENING? IT'S WHEN THE AUTOINDUCERS HAVE ACCUMULATED BECAUSE THAT'S THE SIGNAL THAT THE HOST IS AT HIGH CELL DENSITY. SO WE THINK THEN THAT BY HAVING THIS VQMA RECEPTOR, THE PHAGE BY POSSESSING THAT IT HAS A WAY TO SURVEIL HOST CELL DENSITY USING THIS AUTOINDUCER THAT JUST BEHIND FOUND. THAT TO US WAS REALLY INTERESTING BECAUSE FOR ALL OF THESE, YOU KNOW, 80 YEARS OF MOLECULAR BIOLOGY FIELD, WHICH LAMBDA, YOU KNOW PHAGE LAMBDA FOUNDED THE FEEL OF MOLECULAR BIOLOGY, IT'S ALWAYS BEEN THOUGHT THAT THE ONLY THING PHAGES TUNE INTO IS HOST DNA DAMAGE FOR HOST CELL STRESS. AND NOW WHAT I'M TRYING TO TELL YOU IS THAT THAT IS TRUE FOR THIS PHAGE BUT MAYBE IT CAN SENSE SOMETHING ELSE, USING THIS RECEPTOR, WHICH IS QUORUM SENSING AUTOINDUCER. SO THE NEXT TASK ON JUSTIN'S PLATE -- ANYWAY, THE NEXT THING FOR JUSTIN TO DO WAS TO ASK, OKAY, SO HOW ARE THESE -- THIS CLASSIC LYSIS LYSOGENY SWITCH, HOW IS THAT CONNECTED TO THE QUORUM SENSING EAVESDROPPING MECHANISM. HOW CAN IT BE? WE KNOW YOU HAVE TO TURN ON THE LYSIS GENE. HOW DOES THAT HAPPEN. WE THINK IT WILL BE SUPER EASY. VQMA PHASE, IT'S A TRANSCRIPTION FACTOR, IT BOUNDS DNA, WE THINK HOW EASY IS THAT? WHAT'S GOING TO HAPPEN IS THAT VQMA, AT HIGH CELL DENSITY WILL TURN ON Q, IT WILL TURN ON THE LYSIS GENE AND ALL THE CELLS WILL DIE. AND JUSTIN TESTED THAT. TOTALLY WRONG. [ LAUGHTER ] SAID OKAY, WE'RE GENETICIST, A REPRESSOR OF A REPRESSOR WILL WORK. WE WILL STEP OUR WAY BACK ONE STEP BACK IN THE PATHWAY, THAT'S HOW IT WORKS. TOTALLY WRONG. NOW WE ARE OUT OF COMPONENTS THAT WE ACTUALLY UNDERSTOOD AND WE HAD TO INFER THAT THERE WAS SOME MISSING COMPONENT THAT COMPLETES THAT CIRCUIT AND CONNECTS THIS PHAGE EAVESDROPPING TO THE CLASSIC LYSIS LYSOGENY. JUSTIN DID A GENETIC SCREEN. HE CHOPPED UP THE PHAGE GENOME AND INTO E. COLI, HE PUT VQMA, AND E. COLI MAKES DPO AND THEY SHOCKED AND CLONED ALL THE PHAGE GENES INTO THE E. COLI CARRYING THE THREE COMPONENT THAT YOU SEE AND LOOKED FOR THE CIRCUIT TO TURN ON. AND SURE ENOUGH, HE FOUND THAT PHAGE COMPONENT TURNED OUT THAT HE GOT EXACTLY ONE GENE OUT OF THAT SCREEN AND IT'S THE ONE I HAVE IN RED THAT'S SITTING RIGHT NEXT DO TO THE VQMA GENE AND THAT GENE ENCODES A 78 AMINO ACID PROTEIN. SO A TINY, TINY LITTLE PROTEIN, 78 AMINO ACIDS AND WHEN JUSTIN TAKES THAT AND DOES A DATABASE SEARCH AGAINST ALL DATABASES, YOU KNOW, HUMAN, VIRAL, BACTERIAL, ALL DATABASES THERE'S NO PROTEIN LIKE THAT IN ANY DATABASE. THAT'S A BRAND NEW PROTEIN. AND BECAUSE OF THAT, JUSTIN GOT TO NAME IT BECAUSE IT WAS HIS PROTEIN AND SO HE CALLS IT Q TIP. [ LAUGHTER ] BECAUSE LIKE HIS MENTOR KAI, HE DOES NOT CARE ABOUT BONNIE BASSLER'S REPUTATION. RIGHT? AND HE SAYS BONNIE, THIS JUST -- IT MEANS -- AND I HAVE TO PUT THIS -- YOU NOTICE I DON'T PUT MANY WORDS ON MY SLIDE. BUT IT MEANS, BONNIE, QUORUM TRIGGERED INACTIVATORS OF C1 PROTEIN. IT'S OBVIOUS. IT ROLLS OFF YOUR TONGUE, BONNIE. [ LAUGHTER ] I ALWAYS HAVE TO -- BECAUSE I HAVE TO WRITE IT ON MY HAND. ANYWAY, SOMEHOW QTIP IS THIS MAGICAL PROTEIN THAT CONNECTS THESE TWO CIRCUITS, RIGHT? SO THE NEXT QUESTION THEN, OF COURSE IS WHAT IS THIS LITTLE NEW PROTEIN DOING THAT CONNECTS THIS PHAGE EAVESDROPPING NOT LYSIS MACHINERY. AND SO JUSTIN DID A LOT OF EXPERIMENTS TO FIGURE THAT OUT AND I'M JUST GOING TO SHOW YOU THE ONE THAT WORKS. SO WHAT QTIP DOES IS IT SEQUESTERS THAT C1 REPRESSOR. SO WHAT YOU'RE LOOKING AT, THIS IS JUST A PICTURE OF E. COLI UNDER THE MICROSCOPE AND WHAT JUSTIN HAS DONE IS HE'S CLONED C1, YOU KNOW THAT REPRESSOR INTO E. COLI, HE HAS A HALO TAG ON IT. THAT'S WHY IT'S GREEN. WHAT YOU CAN SEE IS ALL THE C1 IS DIFFUSED IN THE CYTOPLASM. AND THEN COMES IN AT THE OLIGOMERS AND THEY LOOK LIKE QTIPS. [ LAUGHTER ] THAT IS HOW THE PROTEIN ACTUALLY GOT ITS NAME, OKAY? SO THEY LOOKED LIKE QTIPS. OKAY? BUT THE OTHER THING -- OKAY. SO THAT'S HOW QTIP WORKS. IT GRABS ON TO THE C1 AND IT INACTIVATES IT AND WE CAN SHOW USING REPORTERS IN EXACTLY THESE CELLS, C1 IS ACTIVE IN THE ONES ON THE LEFT, AND C1 ASK INACTIVE IN THE ONES ON THE RIGHT. SO THAT OLIGOMERATION STEPS ACTIVATES IT AND NOW WHAT I HAVE TOLD YOU SO FAR IN THIS TALK, THERE'S TWO INPUTS. THE FIRST ONE IS CLASSIC. WHEN THE HOST IS IN TROUBLE, THE BACTERIAL HOST IS IN TROUBLE, C1 GETS CLEAVED, Q GETS UNLEASHED AND THAT TURNS ON THE LYSIS GENES. THE SECOND INPUT IS NEW, IT'S QUORUM SENSING, IT'S PHAGE EAVESDROPPING ON QUORUM SENSING. THE PHAGE HAS THIS RECEPTOR. IT'S MONITORING THE BUILDUP OF THE HOST-PRODUCED -- THE AUTOINDUCER DPO. WHEN IT GETS BOUND VQMA, IT SITS AT THE QTIP PROMOTER AND IT PULLS IT OUT INTO THESE OLIGOMER AND THAT LETS Q LOOSE AND IT GOES DOWN AND TURNS ON ALL OF THESE LYSIS GENES. AND SO THE FATE OF C1 IS DIFFERENT. IN THE FIRST CASE IT GETS CLEAVED AND IN THE SECOND CASE, IT'S IN FACT BUT IT'S INACTIVE BECAUSE IN THESE OLIGOMERS. IT WILL GET KILLED, RIGHT? SO THERE'S TWO WAYS FOR THE PHAGE TO GET THERE. BUT IF YOU ALSO REMEMBER FROM FIRST PART OF MY TALK, THERE'S ALSO TWO QUORUM SENSING SYSTEMS RUNNING HERE. SO RIGHT, THIS PHAGE HAS THIS PHAGE QUORUM SENSING SYSTEM THAT I HAVE JUST TOLD YOU ABOUT, BUT, REMEMBER, KAI AND JUSTIN'S WORK, THE HOST USES VQMA. IT BINDS DPO, RIGHT AT HIGH CELL DENSITY AND THE HOST HAS ITS OWN VQMA AND IT TURNS ON THE SMALL RNA AND THAT SMALL RNA CONTROLS HUNDREDS AND HOST GENES THE ENTIRE QUORUM SENSING REGULI. AND IT ALSO TURNS ON VQMR. SO WHILE THIS PHAGE IS GETTING READY TO KILL THE HOST, IT ACTUALLY IS MESSING WITH ALL OF THE HOST BIOLOGY BY TURNING ON THESE HUNDREDS AND HUNDREDS OF GENES. WE ACTUALLY DON'T KNOW WHAT GOOD IT DOES THE PHAGE TO TAKE THAT STEP. IT COULD BE THAT, YOU KNOW, IT GETS ALL KINDS OF RESOURCES AND THINGS THAT HELP IT REPLICATE. WE DON'T KNOW WHY THAT IS GOOD. WE JUST KNOW THAT THAT HAPPENS. THE OPPOSITE IS NOT TRUE. THE HOST VQMA DOES NOT BIND THE QTIP PROMOTER. THAT MAKES SENSE. THE HOST WOULD COMMIT SUICIDE IF THAT HAPPENED, RIGHT? WHAT WE DID WAS WE CRYSTALLIZED MOST OF THOSE PROTEINS. THERE'S TWO AMINO ACID IN THE BINDING DNA THAT MAKES THE VQMA PHAGE PROTEIN. IT'S PROMISCUOUS. BUT THE ACID CHANGE IN THE HOST VQMA MAKES IT ONLY BE ABLE TO BIND AT ITS OWN PROMOTER. RIGHT? AND SO THAT'S HOW THAT'S WORKED AND WE DID A SWAPEROO AND IT WORKED. SO THE VQMA PHAGE IS MORE VERSE FILE, IT TURNS ON THE PHAGE AND THE HOST GENES AND THE HOST VQMA JUST WORKED IN THE HOST. ONCE JUSTIN GOT THIS FAR. WE THOUGHT WE WERE ACTUALLY LEARNING SOMETHING ABOUT HOW THIS SYSTEM -- YOU KNOW, THE MECHANISM FOR HOW THIS SYSTEM WORKS BUT WE REALLY STARTED TO GET WORRIED THAT THIS WAS JUST SOME ACCIDENT IN EVOLUTION THAT THIS WEIRDO PHAGE, YOU KNOW, THAT NOBODY HAD EVER WORKED ON HAD SOMEHOW PICKED UP THIS GENE AND IT WOULD BE A ONE OFF, RIGHT? BUT NOW THAT JUSTIN HAD THE TWO GENE MODULE AND HE THAT IS TRANSCRIPTION FACTOR AND QTIP, RIGHT, TOGETHER HE COULD TAKE THOSE TWO GENES TO GO AND THEN WHEN HE SEARCHED THE DATABASE WITH THOSE -- WITH THAT ENTIRE MODULE, WHAT HE FOUND IS THAT THIS IS NOT A ONE OFF. THERE ARE TONS AND TONS OF PHAGES, NONE OF WHICH HAVE EVER BEEN STUDIED THAT ALL HAVE A MODULE LIKE THIS. AND WHAT I MEAN BY THAT IS THEY ENCODE A TRANSCRIPTION FACTOR IN ONE DIRECTION AND THEN GOING IN THE OPPOSITE DIRECTION THEY ALL HAVE A TINY LITTLE PROTEIN, A GENE TINY LITTLE PROTEIN. EVERY ONE OF THOSE TRANSCRIPTION FACTORS HAS WHAT IS CALLED A PAST DOMAIN, WHICH IS HOW THEY BIND LIGANDS THEY ARE TRANSCRIPTION FACTORS. WE DON'T EVEN KNOW WHERE THESE PHAGES -- THEY ARE JUST A, Gs, Ts AND Cs IN THE DATABASE. WE DON'T KNOW WHERE THESE HOSTS ARE. THEY ALL BIND SOME HOST OR ENVIRONMENTAL SIGNAL THAT'S APPROPRIATE FOR THAT HOST BIOLOGY AND THEN THEY USE THESE QTIP ANTI-REPRESSORS TO CONNECT TO THE CLASSIC LYSIS LYSOGENY MACHINE. IF YOU TAKE THE QTIPS AND RESEARCH. THERE'S NO HOMOLOGY, BUT THEY ALL DO THE SAME THING. THEY ALL WORK UNDER C1. SO THEN WHAT I'M SAYING TO YOU, WE THINK THIS WILL BE COMMON. AND IN THE CASE OF THE PHAGE THAT WE'RE STUDYING, THE PHAGE IS MONITOR HOST QUORUM SENSING, IT'S CONNECTING THAT HOST CELL DENSITY INFORMATION, USING QTIP TO THE LYSIS LYSOGENY MACHINERY. IN THE CASE OF ALL OF THESE OTHER PHAGES, WE DON'T KNOW, BUT WE ARE GUESSING THAT THEY USE THESE TRANSCRIPTION FACTORS TO DETECT SOME SENSORY INPUT, AND THEN THEY HAVE AN ANTI-REPRESSOR-LIKE QTIP, THAT THEN CONNECTS IMPORTANT INFORMATION THAT THESE HOSTS ARE DETECTING, OR THE PHAGES ARE DETECTING TO THESE LIFESTYLE SWITCHES OF THE PHAGE. SO ANYWAY, WE'RE NOW STARTING TO STUDY ALL OF THESE. WHAT WE FOUND RECENTLY -- AND I DON'T KNOW WHY WE DIDN'T DO THIS BEFORE. WE WERE SCANNING PHAGE GENOMES AND THEY ARE LOADED WITH QUORUM SENSING GENES. WE EVEN HAVE PHAGES THAT MAKE THEIR OWN AUTOINDUCERS. SO THEY HAVE THE PHASE GENE ON THEM. EVEN THOUGH JUSTIN FOUND THE FIRST CONNECTION BETWEEN PHAGES AND QUORUM SENSING. WE THINK THIS INTERDOMAIN, USING QUORUM SENSING, WE KNOW THERE ARE ALL KINDS OF VARIATIONS IN IT, BESIDES THIS ONE, RIGHT, AND THAT WE THINK THAT THERE WILL BE A LOT OF CROSS TALK BETWEEN THESE ORGANISMS OR PHAGES AND BACTERIA THAT ARE EXPLOITING OR USING OR TRICKERY WITH QUORUM SENSING MOLECULES. AND THAT'S LIKE A NEW AREA OF THE LAB. BUT JUST ONE MORE EXPERIMENT THAT YOU GUYS HAVE TO -- BECAUSE I STILL HAVEN'T LET JUSTIN GRADUATE. [ LAUGHTER ] ANYWAY, ONE MORE. ONE MORE. WHEN JUSTIN GOT HERE, RIGHT, AND WE STARTED TO THINK, OKAY, THESE ARE -- YEAH, I GUESS I DON'T SOUND LIKE A VERY GOOD MENTOR. MAYBE THESE PHAGES ARE TALKING BACK AND FORTH WITH THESE BACTERIA. THEN WE THOUGHT, YOU KNOW, THIS COULD -- THERE COULD BE MORE TO IT THAN THIS. AND WHAT I MEAN BY THAT, IS BESIDES HOST PHAGE COMMUNICATION, THROUGH QUORUM SENSING, WE THOUGHT MAYBE THIS IS ABOUT PHAGE-PHAGE TALKING OR PHAGE-PHAGE COMPETITION. WHAT YOU MAY OR MAY NOT KNOW IS HOST BACTERIA IN THE BIOSPHERE, INCLUDING LABORATORY COLI, THEY ARE POLYLYSOGENS. JUST LIKE OUR GENOMES ARE LOADED UP WITH VIRAL BACTERIAL. AND WHAT JUSTIN FOUND AFTER HE DID WHAT I TOLD YOU. YOU TAKE THE PINK ONE, WE HAVE FOUND BACTERIA THAT HAVE THE PHAGE AND HAVE THE QTIP MODULE. AND THEN WE FOUND THAT IT'S COMMON. WE HAVE OTHER BACTERIA THAT HAS DIFFERENT PHAGE AND NOW WE HAVE FOUND NATURALLY OCCURRING BACTERIA HAS TWO PHAGES AND IT BINDS ITS OWN LIGAND AND THE QTIP MODULE. WE STARTED TO WONDER WHAT HAPPENS WHEN THEY ARE IN A SINGLE HOST CELL, COULD IT BE THAT NOT ONLY DO THEY GIVE THEM A LEG UP ON THE HOST, MAYBE IT GIVES THE PHAGE A LEG UP ON A COMPETING PHAGE. PEOPLE STUDY POLYLYSOGENY, THEY THINK WHEN IT GOES TO THE LYTIC CYCLE, WHICH EVER PHAGE CAN GOBBLE UP MORE RESOURCES AND THAT PHAGE MAKES MORE PROGENY THAN THE COMPETITOR PHAGE. WE THOUGHT MAYBE THESE MODULES COULD CHANGE THAT RACE. HERE'S THE FINAL EXPERIMENT THAT I WILL SHOW YOU FOR TONIGHT. SO YOU GET IT. WE HAVE A BACTERIAL HOST, A SINGLE HOST THAT'S CARRYING TWO OF THESE PHAGES AND EACH HAS A QTIP TRANSCRIPT FACTOR AND I CALL THEM THE PINK ONE AND THE BLUE ONE. THE TRANSCRIPTION FACTOR ON THE TOP BINDS A LIGAND. IT TURNS ON THE QTIP AND IT THE ACT ON THE PINK ONE. THE TRANSCRIPTION FACTOR BINDS A DIFFERENT LIGAND AND IT TURNS ON ITS QTIP AND IT WORKS ON THE BLUE C1. BOTH OF THOSE PHAGES ARE IN THE SAME CELL. AND IF WE SUBJECT THEM TO CELL DAMAGE, WHAT HAPPENS? WE TAKE THE CELLS AND WE DO -- WE CAUSE DNA DAMAGE, WHAT HAPPENS? THE NORMAL THING HAPPENS BOTH OF THE C1s GET CLEAVED JUST LIKE LAMBDA AND THAT UNLEASHES Q AND BOTH PHAGES START THE RACE. THEY START MAKING VIRIONS BOTH OF THEM AND THEN IF WE COLLECT UP THE VIRIONS AFTER THE CELLS DIE, AND THEN WE JUST SEQUENCE THE GENOMES AND WE COUNT HOME GENOMES OF THE PINK PHAGE AND THE BLUE PHAGE. ABOUT HALF ARE THE PINK ONES AND HALF OF THE VIRIONS ARE A BLUE ONE. IT'S A RACE, AS EVERYBODY THOUGHT. AND IN THIS CASE, SORT OF NOBODY WINS. THEY TIE. ALL RIGHT. SO WHAT IF WE DO A DIFFERENT EXPERIMENT. WHAT IF INSTEAD OF DOING THE CLASSIC DNA DAMAGE EXPERIMENT, WE GIVE THE LIGAND FOR THE TOP PHAGE, THE PINK PHAGE. WHAT HAPPENS IS THAT LIGAND IS PROVIDED, RIGHT THAT TRANSCRIPTION FACTOR WILL BIND IT. IT'S ACTIVATED AND TURN ON ITS QTIP BUT THE BOTTOM PHAGE DOES NOT DETECT THAT LIGAND AND THERE'S NO DNA DAMAGE. IT'S BASICALLY ASLEEP. AND SO WHAT HAPPENS THEN IS THAT QTIP GETS MADE BY THE TOP PHAGE. IT IS EXQUISITELY SPECIFIC AND IT ACTIVATES IT AND INDUCES LICE SIS IN THE TOP PHAGE BUT THE BOTTOM PHAGE IS LIVING ALONG. ITS INPUT IS NOT THERE. AND THERE'S NO DNA DAMAGE, IT'S A LYSOGENE. AND NOW IF WE COUNT UP THE GENOMES OUTSIDE, THERE'S 100 TIMES MORE OF THE PINK PHAGE THAN THE BLUE PHAGE AND THE PINK PHAGE WINS. WE CAN DO THE EXACT -- JUSTIN CAN DO THE EXACT OPPOSITE EXPERIMENT AND NOW IF WE GIVE THE LIGAND THAT THE BOTTOM TRANSCRIPTION FACTOR. IT BINDS AND TURNS ON THE QTIP. THAT GLOMS ON TO THE BLUE C1 AND THE PINK PHAGE IS ASLEEP THIS TIME, AND THE BLUE PHAGE MAKES VIRIONS AND THE PINK PHAGE DOES IT AND NOW WHEN WE CONSEQUENCE WHAT IS OUT THERE, THERE'S 100 TIMES MORE OF THE BLUE PHAGE THAN THE PINK ONE. WHAT WE THINK IS NOT ONLY DO THESE MODULES, PERHAPS ALLOW THE PHAGES TO TAKE IN INFORMATION ABOUT THEIR HOSTS, THEY ALSO DEPENDING ON WHICH OF THOSE STIMULI ARE THERE CAN HELP WITH THIS PHAGE-PHAGE COMPETITION. AND SO THEY BOTH TRICK THEIR HOST AND THEY TRICK THEIR COMPETITORS AND MAYBE MAKE MORE OF THEMSELVES AND MAKE MORE PROGENY DEPENDING ON WHAT IS HAPPENING IN THE ENVIRONMENT. OKAY. THAT'S IT. I WANT TO TRY TO PUT ALL OF THIS TOGETHER BECAUSE I SORT OF GOT TO DO IT MIDWAY. OKAY. SO CHOLERA, WHEN IT GETS -- SO FIRST TALKING ABOUT CALLER ARE A, THE -- CHOLERA, THE HOST OF THE PHAGE. IT HAS TO MAKE A DECISION, SHOULD I STAY OR SHOULD I GO? SHOULD I STAY OR SHOULD I GO? QUORUM SENSING MODULATES THAT DECISION. IN THIS CASE, THIS NEW AUTOINDUCER DPO, WHEN IT ACCUMULATES, THE HOST VQMA BINDS IT AND WHEN THAT HAPPENS, REMEMBER, HOST TURNS OFFER THE VIRULENCE FACTOR AND TURNS OFF THE BIOFILM GENES AND IT DISPERSES. YOU'RE GOING TO REMEMBER THAT I TOLD YOU THAT TONS OF DIFFERENT BACTERIA MAKE DPO. THAT INCLUDES MICROBIOME BACTERIA. AND SO THERE'S DONEES DEPENDING ON WHAT SOMEONE HAS IN THEIR GUT. THEY ARE MAKING DPO AND WHAT HAPPENS WHEN THERE'S A LOT OF DPO THERE, CHOLERA DISPERSES. AND SO IT TURNS OUT -- THIS HAS BEEN DONE IN A MOUSE, AND NOT A HUMAN. DEPENDING ON WHETHER OR NOT THE MICROBIOME, CHOLERA DISPERSES EARLY. WHAT WE THINK THEN IS YOUR MICROBIOME BY MAKING THIS MOLECULE, IT IS FENDING OFF THIS PREDATOR, BY MAKING CHOLERA MISCOUNT. RIGHT? SO THIS IS A MULTISPECIES CONVERSATION, WHERE THE MICROBIOME IS ACTUALLY GETTING RID OF THE PREDATOR BY MAKING THIS AUTOINDUCER. IT IS KNOWN IN HUMANS, THAT SOME HUMANS GET VERY SEVERE CHOLERA DISEASE AND SOME GET VERY MILD CHOLERA DISEASE. FANTASY IS THAT MAY HAVE TO DO WITH THE BLEND OF THE MICROBIOME AND DPO IS THERE. IT WORKS LIKE THAT IN A MOUSE. THE MOLECULES MADE FROM 3ANINE, YOU, THE HUMAN HOST ARE PARTICIPATING IN THIS CONVERSATION. SO YOUR INTESTINAL EPITHELIAL CELLS ARE COVERED WITH THIS STICKY, AND IT KEEPS YOU AWAY FROM THE CELLS. AND THEY EAT MUCIN FOR A LIVING AND YOU PROVIDE THEM AS A MUCIN AS A FOOD SOURCE AND EVERYTHING STAYS IN HARMONY. SO YOU, THE HUMAN HOST, BY GIVING YOUR BACTERIA THIS -- THIS MUCIN ARE ACTUALLY GIVING THEM THE THREONINE THAT THEY NEED TO MAKE DPO. THE BACTERIA WILL NOT MAKE DPO FROM THE THREANINE, IT'S NOT AN ESSENTIAL AMINO ACID. AND SO THEY MUST PUT IT PROTEINS. SO ONLY MAKE THIS FROM EXTERNAL SOURCE. WE THINK THIS IS A THREE-WAY CONVERSATION BETWEEN THE EUKARYOTES, THE HUMAN HOST AND THE MICROBACTERIA AND THE HUMAN HOST. YOU GIVE THEM WHAT THEY NEED TO MAKE CHOLERA MISCOUNT AND LEAVE EARLY. AND SO WE HAVE A FANTASY -- ANOTHER FANTASY, THIS IS REALLY GETTING IN THE FANTASTICAL RANGE. MAYBE THIS COULD BE A MEDICINE WHERE WE COULD GIVE DPO OR THREANINE AS A SIMPLE MEDICINE OR PROPHYLACTIC WHERE CHOLERA EXISTS. THEN, OF COURSE THERE'S THE PARASITE OF THE PARASITE. NOW WE HAVE THESE PHAGES AND REMEMBER THESE PHAGES ARE ALSO TRYING TO OPTIMIZE OFF OF THIS DPO. SO THEY ARE DETECTING WHETHER -- HOW MUCH DPO IS THERE AND THEY ARE ALSO MAKING A SIMILAR TRANSITION TO CHOLERA. SHOULD I STAY OR SHOULD I GO? BUT IN THIS CASE, IN THEIR BACTERIAL HOSTS. AND SOMEHOW EVERYBODY IS -- NOT EVERYBODY, BUT LOTS OF ORGANISMS ARE USING THIS SIMPLE MOLECULE OF DPO TO DECIDE TO LEAVE OR GO. WE DON'T KNOW HOW ANYBODY KNOWS WHO IS MAKING THE DPO AND HOW THEY ACTUALLY GET ROBUST INFORMATION OUT OF THIS MOLECULE, GIVEN THAT THERE'S ALL KINDS OF DIFFERENT ORGANISMS PARTICIPATING IN THE PRODUCTION OF THE MOLECULE. AND THEN, OF COURSE ON TOP OF THAT, WE NOW HAVE TO THINK ABOUT S.O.S. WE HAVE TO THINK ABOUT THESE OTHER STIMULI THAT ARE ALSO CHANGING WHETHER OR NOT THESE PHAGES ARE STAYING IN THEIR CURRENT HOSTS OR THEY ARE TURNING ON THREE LYTIC PROGRAMS AND ALL OF THAT MESS IS HAPPENING IN YOUR INTESTINE AND ALSO IN ALL OF THESE OTHER ENVIRONMENTAL NICHES THAT ARE ANALOGS ON THIS. WHAT IS ON THE HORIZON FOR MY GANG IS TO START UP TO GEN UP EXPERIMENTS THAT LOOK A LOT MORE LIKE THIS REAL THING WHERE WE HAVE MULTIPLE SPECIES PRESENT AND WE HAVE SPACE AND WE HAVE BIOFILMS AND HUMAN CELLS THERE. I THINK THE NEW HORIZON IS TO START TO ASK HOW QUORUM SENSING WORKS IN SPACE AND TIME, AND AUTHENTIC SITUATIONS, RIGHT, WITH MULTIPLE SPECIES FROM DIFFERENT DOMAINS PRESENT. AND SO THAT'S WHERE WE'RE GOING IN THE LAB, BUT -- WELL, I NEED A JOB, AND THAT'S WHERE WE'RE GOING. BUT ANYWAY, IT'S FOR ME, IT'S PRETTY EXCITING BECAUSE I NEVER WORKED ON ANYTHING EXCEPT BACTERIA BEFORE. IT'S FUN AND EXCITING FOR ME TO LEARN ABOUT PHAGES AND BEFORE HUMAN CELLS AND TRY TO THINK ABOUT THAT. FOR THE GRADUATE STUDENTS IN THE AUDIENCE, WE DID GRADUATE! YEAH. SO TONIGHT'S HERO IS JUSTIN SILPE. AND KAI FOUND THE SMALL RNA. AND JUSTIN SILPE DID ALL THE WORK. HE FOUND THE MOLECULES AND ALL THE PHAGE EXPERIMENTS THAT I TOLD YOU ABOUT AND THEN HE WENT OFF TO A POSTDOC AT HARVARD. HE LANDED JELLY SIDE UP. I DO GRADUATE FROM MY LAB. AND THEN I JUST WANT TO ONE MORE TIME, SINCE I HEAR, YOU KNOW, JUST SAY THAT ONE OF MY BIGGEST PRIDE AND JOYS EVER, RIGHT, YOU GUYS HAPPILY, VERY HAPPILY STOLE FROM ME, JULIA VAN KESSEL, AND YOU ARE SO LUCKY TO HAVE HER. SHE WAS A POWERHOUSE SUPERSTAR IN MY LAB BUT I'M NOT GOING TO DO HER PRESS. I WILL DO MINE ON THIS TALK. IT'S A SPECIAL DELIGHT. CLAY AND I HAVE BEEN FRIENDS SINCE THE START OF OUR CAREERS. JULIA CAME ALONG A LITTLE LATER THAN THAT, AND IT'S A REALLY SPECIAL TREAT FOR ME TO GIVE THESE LECTURES, THESE NICE PUBLIC LECTURES AND THE BROAD LECTURES. I NEVER TRY TO TALK ANYWHERE TWICE. I TRY TO LEAVE IMMEDIATELY AFTER BEFORE YOU REALIZE THAT NOTHING I SAID MADE ANY SENSE, RIGHT? BUT ANYWAY, I'M HERE ALL WEEK AND IT'S A SUPER HONOR FOR ME TO BE INVITED BY THE PATTEN COMMITTEE BUT IT'S A SPECIAL HONOR BECAUSE THESE LIFELONG FRIENDS AND MENTEES WHO HAVE GONE ON TO BIGGER AND BETTER THINGS ARE HERE AND THAT JUST MAKES IT EXTRA WONDERFUL FOR ME. SO THANK YOU FOR HAVING ME. I'M HAPPY TO ANSWER QUESTIONS. [ APPLAUSE ] >> Audience Member: WELL, AS SOMEONE WHO HAS ONE TIME WORKED WITH ANATOL AND HOW TO INDUCING LYSIS. YOU HAVEN'T MENTIONED ANYTHING ABOUT ARCHAEA. >> Bonnie Bassler: SO THEY ARE THE MISSING DOMAIN, RIGHT SO FAR. BUT ACTUALLY, MICKEY PULCHA AT UPENN, SHE THINKS SHE HAS A THE FIRST AUTOINDUCER IN AN ARCHAEAN. THEY HAVE A BEAUTIFUL STORY WHERE IT'S AN AMAZING PHENOTYPE, WHERE IT CHANGES FROM LIKE A ROD TO A DISC. AND SO IT'S A FANTASTIC PHENOTYPE AND SHE HAS SOUPS THAT ACCUMULATE AT HIGH CELL DENSITY. SHE MIGHT HAVE THE FIRST AUTOINDUCER AND THAT WOULD BE AWESOME! RIGHT? THEY BETTER HAVE IT. OBVIOUSLY I'M BRAIN WASHED. I THINK QUORUM SENSING RUNS EVERYTHING, RIGHT? BUT ANYWAY, THAT'S NOT OUR WORK. SHE'S JUST A FANTASTIC FROM THE LAB NEXT DOOR TO MINE WHO THINKS SHE HAS GOT THAT. I THINK THAT'S COMING. YEAH. >> Audience Member: HAVE YOU DONE MASS SPEC ON THE INCLUSION BODIES THAT THEY ONLY CONTAIN THE QTIP. >> Bonnie Bassler: YES. IT'S NOT LIKE QTIP GOES UP AND GLOM ALL THE PROTEINS. IT STICKS TO C1 AND NOTHING ELSE. WE HAVE DONE EXACTLY THAT EXPERIMENT AND WE PURIFIED THOSE INCLUDED BODIES AND THEY ARE THE ONLY TWO PROTEINS IN THERE. THE QTIP, THE ONE I TOLD YOU ABOUT, IT DOESN'T ADHERE TO ANY OF THOSE OTHER C1s. IT DOESN'T -- IT DOESN'T STICK TO LAMBDA C1. THEY ARE INCREDIBLY SPECIFIC. THE TERRIBLE PART OR WHATEVER, THE FRUSTRATING PART ABOUT THIS IS WE HAVE NOT GOTTEN A CRYSTAL STRUCTURE OF QTIP, RIGHT? WHEN WE TRY TO PURIFY IT, IT COMES DOWN AS THIS GLOB. IT'S REALLY STICKY. WE DO NOT UNDERSTAND THE MECHANISM. WE HAVE -- WE DID ALANINE AND WE HAVE MUTANTS THAT DON'T THAT I IT TO THE POLL. WE HAVE MUTANTS THAT DON'T BIND C1 BUT WE DON'T HAVE AN ATOMIC LEVEL LOOK AT THAT YET. I THOUGHT THAT WAS GOING TO BE A SNAP, RIGHT? AND IT'S NOT TURNED OUT TO BE SO. WE DID ALL KINDS OF TRICKS. WE TETHERED IT TO C1 AND PUT SOLUBILITY, BUT ITS JOB -- I'M MAKING EXCUSES. THE JOB IS TO BE REALLY STICKY AND SO THAT'S REALLY BEEN A PROBLEM FOR US. BUT IT IS EXTREMELY SPECIFIC. I JUST DON'T KNOW HOW IT GETS THAT SPECIFIC. THAT'S LIKE TMI. HE DIDN'T EVEN ASK ME TO TELL YOU THE EXPERIMENTS THAT AREN'T WORKING. YEAH, YEAH, IT'S ALL THERE. >> Audience Member: ONE QUESTION. SO YOUR -- FIRST OF ALL, FANTASTIC PRESENTATION. AS A PHYSICIST, I NEVER HEAR THIS STUFF. SO IT WAS FASCINATING. YOU SAID THAT THIS QUESTION THAT YOU HAD, AT SOME POINT, YOU KNOW, DPO IS LIKE EVERYWHERE, BUT THE VQMA WAS VERY PECULIAR OR PARTICULAR HASN'T BEEN ANSWERED, AND I WAS WONDERING ISN'T IT -- OR COULD IT BE THAT THE -- THE ACTUAL, YOU KNOW -- I DON'T KNOW WHAT YOU CALL IT, RECEPTOR OF THE DPO IS ACTUALLY IN ALL OF THESE PHAGES AND MAYBE THE CHOLERA IS KIND OF THE ODD ONE OUT? >> Bonnie Bassler: OR VIBRIO. MAYBE. SO EVERY VIBRIO HAS VQMA, RIGHT. SO VIBRIOS DO, THIS RIGHT? AND SO IT COULD BE -- AND TRANSCRIPTION FACTORS ARE SUPER GENERIC PROTEINS. SO IT COULD BE -- YES, THAT COULD BE TRUE. RIGHT. AND IT COULD ALSO BE THAT SOME BACTERIA DON'T DETECT THE MOLECULE, IT'S A WASTE PRODUCT OR THERE'S SOME OTHER RECEPTOR THAT DOESN'T LOOK ANYTHING LIKE VQMA. THE EXPERIMENT, WE ARE TYING A MICROBACTERIUM, AND WE ARE GOING TO TRY TO SEE IF WE CAN FIND USING GENETICS A DIFFERENT RECEPTOR, BUT WE HAVE TO MAKE A GUESS THAT THEY ARE RESPONDING TO THE MOLECULE. IT COULD BE EXACTLY WHAT YOU SAID. AND IT COULD JUST BE THAT CHOLERA IS THE ONLY ONE THAT DETECTS IT, RIGHT? AND ITS PHAGES. YEAH. YEAH. YEAH. [ OFF MICROPHONE COMMENT ] >> Bonnie Bassler: THE RECEPTORS ARE KINASES AND PHOSPHOPHASES. SO IF YOU -- YOU HAVE ALL OF THESE KINASE. SO ALWAYS -- SO THE SIGNALS HAVE DIFFERENT HALF LIVES AND DIFFERENT STRENGTHS AND ALWAYS THE SELF-SIGNAL IS MORE POWERFUL. SO DPO IS NOT A SELF-SIGNAL. IT'S A GENERIC SIGNAL AND IT'S A WIMPY SIGNAL. BUT THEY WORK SYNERGISTICALLY, YEAH. BUT THAT HAS TO DO WITH THE WAY THE RECEPTORS WORK. YOU LOCK 'EM, RIGHT? BUT IF YOU GOT RID OF THE TWO RECEPTORS IT WORKS PERFECTLY FINE, RIGHT? YEAH. MM-HMM. MALCOLM [ OFF MICROPHONE COMMENT ] >> Bonnie Bassler: NO. YEAH. RIGHT. YEAH. YEAH. HE'S ASKING ME ABOUT -- I THINK MALCOLM IS ASKING ME -- HE'S ASKING ME HOW DID DPO GET MADE? AND IS THERE A TOXIC INTERMEDIATE AND THEY LEAK IT OUT. THERE'S NOT A -- REMEMBER I TALKED ABOUT THAT LAST NIGHT. THERE'S NOT A TOXIC INTERMEDIATE. THE TRICK IS YOU HAVE TO GIVE THEM EXTERNAL THREANINE. DELANEY LACY WHO FOR THE GRADUATE STUDENTS IS GRADUATING ON MONDAY. [ LAUGHTER ] YEAH. SHE FIGURED EVERY STEP OUT AND SO WE THINK THAT -- WE THINK THE DPO MIGHT BE MUCH MORE ABOUT THE ENVIRONMENT, RIGHT? YOU KNOW, YOU HAVE TO HAVE THREANINE AROUND AND THEN THEY HAVE -- THREANINE IS VERY SCARCE THEY MAKE IT BUT THEY NEED TO USE IT ALL TO MAKE PROTEINS AND SO WE THINK THAT MAYBE DPO IS ABOUT, LIKE THE ENVIRONMENTAL CONDITIONS ARE VITAL, YOU KNOW THERE'S A LOT OF MUCIN AROUND, RIGHT? WE DON'T ACTUALLY KNOW HOW IT'S CONTROLLED OTHER THAN THE MORE THREANINE, THE MORE OF THAT MOLECULE THEY MAKE. THAT'S ALL WE KNOW, MALCOLM. YES. YEAH. SO -- RIGHT. SO IT'S -- YES. RIGHT? BECAUSE I THINK WHAT YOU'RE ASKING ME IS WHY AREN'T THEY ALL DEAD, RIGHT? YEAH. RIGHT SO MALCOLM, RIGHT -- THIS IS LIKE, LOOK AT THE TIME, YOU GUYS, GO! [ LAUGHTER ] MALCOLM, WE'RE SUPPOSED TO BE FRIENDS. ANYWAY, YEAH. HERE'S WHAT MALCOLM IS ASKING ME. RIGHT. OKAY. HERE YOU GOT THIS STATE THAT LISTENS INTO DPO IF WE SQUIRT DPO, THEY KILL ALL THE CHOLERA AND THEY KILL ANYBODY. AND HE'S ASKING ME WHY ARE THE CHOLERA ALIVE AND THAT'S BECAUSE THERE'S TWO SIGNALS, THE DPO AND YOU HAVE TO ADD SOMETHING ELSE THAT WE ARE TRYING TO FIND AND THAT'S WHY THE PHAGE ACTUALLY EXISTS. THEY DON'T JUST AUTOMATICALLY KILL THE CELLS WITH JUST DPO. SO WE HAVE TO PUMP IT UP WITH ANOTHER SIGNAL. AND THEN THAT'S WHY WE GOT IT, RIGHT? YEAH. WE'RE REALLY ON THE HUNT FOR THAT ONE. YEAH. HAS TO BE LIKE -- THAT'S WHAT WE SUSPECT. IT HAS TO BE LIKE THAT. YEAH. MM-HMM. >> Audience Member: HI, YOU HAVE THE MOLECULE AND WE HAVE ALSO SO CAN YOU HAVE THE PROTEIN OF ALL THE BACTERIUM? >> Bonnie Bassler: WE TRIED. WE ARE NOT PARTICULARLY GOOD AT BIOINFORMATIC. WE ARE OKAY, BUT THAT IDEA OF TRYING TO JUST -- SO WE HAVE A CRYSTAL, RIGHT, OF VQMA WITH THE MOLECULE. WE KNOW WHAT THE LIGAND BINDING SITE. IS WE HAVE DONE BABY -- AMATEUR WAYS -- CAN WE JUST FIND WHAT THE RECEPTORS ARE BY LOOKING FOR A SIMILAR BINDING SITE? THAT SHOULD WORK AND WE HAVE NOT GOTTEN THAT TO WORK YET AND MAYBE WE SHOULD TRY HARDER ON DOING THAT BECAUSE YOU'RE RIGHT IF WE COULD NARROW THAT DOWN AND KNOW WHO TO LOOK FOR, THAT WOULD BE COOL. THAT'S A VERY GOOD IDEA. YEAH. MM-HMM. [ OFF MICROPHONE COMMENT ] >> Bonnie Bassler: YEAH. MM-HMM. YEAH. I WILL REPEAT THAT. RIGHT HE'S ASKING ABOUT THE AFFINITY OF THE HOST FOR -- THE VQMA, VERSUS DPO, VERSUS PHAGE VQMA DPO. THEY ARE IDENTICAL. EVERY LIGAND CONNECTING SITE. THEY HAVE THE SAME KD. THEY ARE OFF BY NOT EVEN TWOFOLD. THE DNA BINDING DOMAINS, THE HOST DNA BINDING DOMAIN IS SLIGHTLY STRONGER. SO THE HOST WORKS TWICE AS GOOD AS THE PHAGE, BUT IT'S NOT SOME BIG REMARKABLE DIFFERENCE LIKE WHERE YOU WOULD SEE, RIGHT, AND THAT'S BECAUSE THE LIGANDS BIND IN THE IDENTICAL BINDING SITE. YEAH. MM-HMM. SO WE DID MEASURE THE KD BOTH FOR BINDING -- THE BINDING LIGAND AND BINDING THE DNA. SAY IT AGAIN. [ OFF MICROPHONE COMMENT ] >> Bonnie Bassler: YEAH. I HAVE NO IDEA. RIGHT? RIGHT, YEAH NOW I LOVE MUCIN, RIGHT? AND THAT'S A CUTE IDEA. YOU WILL. >> HAVE A SIMILAR VIBRIO, AND DO YOU THINK THAT ORIGINAL VBMA WAS A TRANSDUCTION EVENT AND DO YOU THINK THAT'S COMMON MECHANISM FOR HOW THE BACTERIA AND THE VIRUSES KIND OF SHARE THE COMMUNICATION TACTICS. >> Bonnie Bassler: FOR SURE, THEY ARE STEALING EACH OTHER GENES WHAT IS CURIOUS ABOUT THAT. THIS IS THE OTHER PART WHERE I WISH YOU WOULD LEAVE. SO WE DID DO THAT, AND WE'RE -- RIGHT, AND SO THE VQMA, THE VIBRIO VQMA IS A VIBRIO GENE. THE PHAGE VQMA IS NOT A GENE FROM THAT PHAGE AND IT'S NOT A VIBRIO GENE. SO WE DO NOT KNOW WHERE THAT -- IT IS NOT AS SIMPLE -- WE -- IT IS NOT AS SIMPLE AS THE PHAGE JUST STOLE IT. WE SEE ALL KINDS OF THAT IN THESE -- WHERE I'M TELLING YOU THESE PHAGES HAVE QUORUM SENSING GENES. WE CAN TELL THEY GOT THEM FROM THE HOST. WE DON'T KNOW WHO WAS THE ORIGINATOR OF THAT VQMA. EITHER IT HAS NOT BEEN CONSEQUENCED YET OR IT'S GONE. IT'S NOT A VIBRIO GENE AND IT'S NOT ANYTHING LIKE ANY OF THE OTHER GENES ON THAT PHAGE'S GENOME. WE DON'T KNOW WHERE THAT VQMA CAME FROM, WHICH IS WEIRD SINCE ONLY VIBRIOS OTHERWISE HAVE IT. I DON'T KNOW THE ANSWER TO THAT QUESTION. THAT DRIVES ME WILD. I HAVE TO -- YEAH.