Thestrange beautifulandpowerfulworldofmicrobes ThefirstMICROBIOLOGISTandhisMICROSCOPE AntonvanLeeuwenhoek Aclassicalexampleofserendipity BywantingbettermagnifyinglenswithwhichtojudgethequalityoftheclothhewasbuyingLeeuwenhoekdiscoveredbacteria 銅球閥截止閥蝶閥 WhatMicrobiologistsDo Workinalmosteveryindustry fromfood agricultureandpollutioncontroltobiotechnology pharmaceuticalsandhealth governmentagenciesandlabs ineducationasteachersandresearchers Noonemicrobiologistcanstudyeverything That swhypeoplewhobecomemicrobiologistsusuallyfocusonaparticularmicrobeorresearcharea Bacteriologistsfocusonbacteria Virologistsspecializeinviruses Mycologistsstudyfungi EpidemiologiststrackdownoutbreaksofdiseaseImmunologistsstudyhowthebodydefendsitselfagainstmicrobialinvaders Whatisamicroorganism Anorganismthatistoosmalltobeseenclearlywiththenakedeye Generallysinglecells butsomeexistascellclusters oftenworkasacommunityWheredomicrobesfitinthebiologicalworld Microbilacell Efficiencyindeficiency Mostofthevitalorgansofeukaryotesaremissing Thepowerofmicrobeliesinitsspeedygrowth ImaginetheweightofbiomassofE coliafter24hrsunderoptimalgrowth NeverunderestimatethepowerofaMicroorganism Microorganisms justlikeGodcannotbeseenthroughnakedeyebutwecanfeeltheirimpactonusinvariousways Thoughonly3 ofthetotalmicrobialpopulationareharmfultothehumans Withoutknowing wearegettingtheirhelpfromthehistoricdayseg souringofmilk dahi pickels jams dosaandidlymaking wineproductionetc MicrobesarealwaysatWork Mindit Thepressureinsideabacterialcellisabout2atmospheres whichisroughlythesameasthepressureinacar styre Ahumancanbekilledbyexposuretolessthan500radradiation However Deinococcusradioduransisabacterium whichcansurviveexposuretoupto3000000radofionizingradiation Botulin atoxinproducedbyClostridiumbotulinum ishighlytoxicandifeveryonehastobekilledonthisearth lessthan1kgofthistoxinwilldo contd Bacterium asbigastheheadofafruitflyandcaneven holditsbreath Agiantbacterium Thiomargarita sulfurpearlofNamibia Thebacteria 3 4mmwide about100timeslargerthanthelargestknown Epulopiscumfishelsoni Thiomargaritanamibiensislivesonthenitrogenandsulfideontheoceanfloorproducedbyrottingplanktonandalgae Nitratehoweverisnotsteadilyavailable sothey holdtheirbreath whiletheywaitforsomethingtostirupofftheoceanfloor Theydothisbystoringsulfurjustundertheircellwall andkeepingnitrateinabigsac Thiscouldbeoneofthereasonswhythebacteriumissobig AHumongousFungus Didyoueverwonderwhattheworld slargestorganismis Maybeyou dpickanelephantoragiantwhale Well thosechoiceswouldbewrong thisorganismisactuallyasoilFungus Armillariabulbosa foundinanorthernMichiganhardwoodforest Itismostlikelyoneoftheworld soldestorganismsaswell exceeding1 500yearsandweighingover100tons Itisactuallyaplantpathogen whosehyphaepiercetherootsofaspentreesandabsorbnutrientsfromthem Therefore themajorityofthefungusisundergroundandonlytinyedible honeymushrooms FactsAboutMicrobes Microbesoutnumberallotherspeciesandmakeupmostlivingmatter 60 oftheearthsbiomass Lessthan0 5 oftheestimated2to3billionmicrobialspecieshavebeenidentified Microbialcyclingofcriticalchemicalelementssuchascarbonandnitrogenhelpskeeptheworldinhabitableforalllifeforms Microbesgenerateatleasthalftheoxygenwebreathe Microbesarerootsoflife sfamilytree Anunderstandingoftheirgenomeswillhelpusunderstandhowmorecomplexgenomesdeveloped Microbialgenomesaremodestinsizeandrelativelyeasytostudy usuallynomorethan10millionDNAbases comparedwithsome3billioninthehumanandmousegenomes Microbialcommunitiesareexcellentmodelsforunderstandingbiologicalinteractionsandevolution Contd Omnipresent Everythingiseverywhere theenvironmentselects BeijerinckM W Microbesthriveinanamazingdiversityofhabitatsinextremesofheat cold radiation pressure salinity acidity anddarkness andoftenwherenootherlifeformscouldexist StrangeFactsandBacterialRecords Underground ChemolithotrophsfoundinBasaltdeposits1500m 4700ft undergroundinsolidrock TheSky Somebacteriaspendtheirwholelivesintheatmosphere growingandreproducinginthecloudsaboveourheads OnIce SomebacterialspeciesliveintheiceofglaciersandothershaveoftenfoundinthesnowsoftheNorthandSouthpolesat 17and 85 C Contd NotSoCool Somebacteriahavelearnedtoliveinhotsprings Somespeciesarehappyat75 Cwhileothersthinkeventhisiscool SpeciesofAquifexcanliveinwaterashotas95 C Archaeaarehappytogrowdeepseahydrothermalventsat106 CTheDeepSea Bacteria knownasExtremeBarophiles liveatdepthsof 10000mandareabletosurvivepressuresinexcessof1000timestheairpressureatsealevel andtheycannotfunctionproperlyatpressureslessthan400atmospheresandmaydieinacoupleofhoursifbr