Medical Microbiology

180 3 GeneralBacteriology

Table3. 3 Continued:GlossaryofImportantTerminology...

Invertedrepeats Nucleotidesequencesrepeatedinreverseorderattheends

oftransposableDNA

IS Insertionsequences;transposableDNAelements

Cassette Sequenceinagenethatcanbetransferredtoothergenes

byhomologousrecombination

Clone PopulationofidenticalcellsorDNAmolecules

Conjugation Transferofhereditarymaterialinapairingprocess

Lysogenicbacteria Cellswithaphagegenome(prophage)integratedintotheir

chromosomes

Lysogenicconversion Changeincellphenotypebroughtaboutbyprophagegenes

MessengerRNA SynthesizedattheDNAbytranscription;carriesgenetic

informationtotheribosomes

Modification

enzymes

MethylasesthatlabelDNAas“self”bymethylation

Mutation Apermanentalterationofthegenome

Nucleoid Nuclearregion,nucleusequivalent

Operator DNAsequenceofanoperon;regulatorbindingsite

Operon Regulatoryunitcomprisingthepromoter,operator,structur-

algenes,andterminator

Parasexuality Unilateralgenetransferfromadonortoareceptor

Phenotype Thetotalityofcharacteristicsexpressedinabacterialcell

Plasmid Extrachromosomal,autonomous,inmostcasescircularDNA

molecule

Promoter RecognitionandbindingsiteforRNApolymerase

Prophage Phagegenomeintegratedintothechromosome

Regulator Regulatoryproteinthatcontrolsgenetranscription;repres-

sororactivator

Regulon Functionalunitofgenesatdifferentlocicontrolledbythe

sameregulator

Recombination,

Legitimateor

homologous

recombination

ReplacementofaDNAsequencebyahomologoussequence

fromadifferentgenome;breakageandreunionmodel

3

Kayser, Medical Microbiology © 2005 Thieme