Microbial Genetics PDF

VMA 5114 Principles of Infectious Diseases Microbial Genetics  Contact Information Dr. Chaoqun Yao – “Chao” Office: 03‐102 Faculty Office Building email: [email protected] Phone: (869)‐663‐6817 by WhatsApp  Susceptible host Infectious...

VMA 5114 Principles of Infectious Diseases Microbial Genetics  Contact Information Dr. Chaoqun Yao – “Chao” Office: 03‐102 Faculty Office Building email: [email protected] Phone: (869)‐663‐6817 by WhatsApp  Susceptible host Infectious disease Pathogen Environment Learning Objectives Master structure and function of genetic materials Define DNA replication, transcription & translation Describe mutation Understand transformation  Genomes in NCBI – FYI Group July 14, Dec. 2, July 11, May 16, May 21, May 11, Jan 17, 2015 2016 2017 2018 2019 2020 2022 Viruses 4,720 5,912 7,295 10,579 14,963 19,424 23,918 Bacteria 8,024 14,091 16,489 26,287 32,309 36,383 42,009 Fungi 654 1,057 1,257 1,616 2,181 2,553 3,413 Protozoa 43 57 64 83 109 43 43 Total 13,441 21,117 25,105 38,465 49,562 58,403 69,383 Eukaryotes 1,445 2,065 2,415 2,879 4,223 5,216 8,529  The “transforming principal” is DNA! Virulent strain (S) Avirulent strain (R) Bacterium Pneumococcus causes pneumonia -from Lewin, Genes III, Wiley & Sons publishers, 1987.  Genetic materials – Nucleic acids Building block – Nucleotide monomer that forms nudaelids composed of a nitrogenous base, a five‐ carbon sugar (ribose or deoxyribose), and up to three phosphate groups. deoxyribose in DNA ribose in RNA Components of nucleic acids 6 elements Cooper GM & Hausman RE The Cell 3rd Ed 2004  Structure of nucleic acids  Pyrimidines have a six carbon ring  Purines consist of two joined carbon rings with five and six members.  Elements in a nitrogenous base are labelled numerically, i.e., 1‐6 in pyrimidines, and 1‐9 in purines  Elements in sugar are labelled numerically with a’, such as 3’ and 5’  write down Structure of nucleic acids on study guide  The sugar is connected to the 5117124 nitrogenous base via position 1’.  The nitrogenous base is linked to position 1’ of the sugar by a glycosidic bond from N1 of pyrimidine and N9 of purine  Base, nucleoside & nucleotide Base Nucleoside Nucleotide Abbreviation containsonlysugar contains sugarbase andbase Phosphategroup RNA DNA Adenine Adenosine Adenylic acid AMP dAMP Guanine Guanosine Guanylic acid GMP dGMP Cytosine Cytidine Cytidynic acid CMP dCMP Thymine Thymidine Thymidynic acid dTMP Uracil Uridine Uridynic acid UMP DNA structure DNA structure DNA structure  A always matches with T in 2 hydrogen bands  G always matches with C in 3 hydrogen bands stronger binding vs AIT https://www.youtube.com/watch?v=qy8dk5iS1f0  Central dogma of genetic information write down on 5117 study guide Transcription DNA RNA Protein Reverse Translation Transcription DNA: Coding or sense strand – bearing same sequence as mRNA Template or antisense strand – directing synthesis of mRNA via complementary base pairing  DNA sequence The sequence is read from 5’ to 3’ end of the sense strand – 5’ ACTG 3’. Sense strand  Synthesis of leading and lagging strands of DNA strand basicallyand nal DNA replication is semiconservative, i.e., a parental strand and a daughter strand in a new molecule basicallysayinggreenstrand is the copy Cooper GM & Hausman RE The Cell 3rd Ed 2004 http://www.tokresource.org/tok_classes/biobiobio/biomenu/dna_replication/index.htm Central dogma of genetic information Transcription DNA RNA Protein Reverse Translation Transcription DNA – double stranded RNA – single stranded messenger RNA (mRNA) transfer RNA (tRNA) ribosomal RNA (rRNA)  DNA vs. RNA DNA RNA Double stranded Single stranded deoxyribose ribose Thymidynic acid Uridynic acid A‐T pairing A‐U pairing Nuclear location (EC) Cytoplasmic location (EC) Stable Labile  Transcription in bacterial & animal cells Lewin B Genes VI 1997  write down Transcription differences on study guide 5 17 29 Prokaryotic cells Eukaryotic cells Single RNA polymerase RNA polymerase I, II, & III No introns Introns removed are at made MAY9 he Polycistronic monocistronic No polyadenylation Polyadenylation at 3’ end No 5’ cap Methylated cap at 5’ end  Translation How many nucleotides are there in a codon? The fact: four nucleotides and 20 amino acids Mathematic calculation: One nucleotide: 41=4 Two nucleotides: 42=16 Three nucleotides: 43=64  Translation Genetic evidence for a triplet code Cooper GM & Hausman RE The Cell 3rd Ed 2004 http://paniaguabio.blogspot.com/2013_03_01_archive.html Translation in bacterial cells Translation in bacterial & animal cells  Mutations Change the sequence of DNA! Any base pair of DNA can be mutated. Spontaneous mutation background (~10‐5‐10‐6/locus /generation in bacteria) Induced mutation mutagens – act directly by modifying a particular base or being incorporated into the nucleic acid  Mutation Silent mutation: Mutations without apparent effect ‐ base change in DNA, no change in AA, e.g. CGA(Arg) AGA(Arg) ‐ change in AA, not function change for protein (neutral substitution), e.g. UUA(Leu) AUU(Ile) Missense mutation: change in codon change in AA change in protein function  Mutation Nonsense mutation: change in a coding codon to a termination (stop) codon, resulting in premature termination Frameshift mutations: inserting or deleting number of bp other than a multiple of 3  do this 5117124 Genetic transfer – bacteria  Transformation: acquisition of new genetic markers by incorporation of added DNA  Genetic transfer – bacteria – FYI  Conjunction: “mating” between two bacteria involving transfer of genetic material  Transduction: transfer of bacterial gene from one to another by a phage  Transposition: movement of a transposon to a new site in the genome Learning Objectives Master structure and function of genetic materials Define DNA replication, transcription & translation Describe mutation Understand transformation  Structure and function of genetic materials NH P What are the genetic materials ? nucleotidemonomer noonucleicacids Moleculemadefromnucleotides nucleotidemadeupof 3 components phosphate ribosedeoxyribose pentosesugar Pyrimidines Purines nitrogenousbase Have a Y inuthem Adenine Guanine What is the structure of nucleotides wtheexceptionof racil twotypesofnucleicacids nucleotidescombinetomake DNAor RNA cytosine Thanking asesarelabelledRNA p.fi Nithya DNA Havea 6carbonring ftp.ftwptstyoimfhmegegrbon Elementsinsugararelabelled ribose eg 3 S labellednumerically kaffednumerically What is the structure of DNA? from 1 6 DNA semiconservative helical doublestranded sugarphosphatebackbone carriedhere function geneticmaterialis Whatis structureof RNA singlestranded function involvedin proteinsynthesis regulationofgeneexpression ribosesugar in cytoplasm DNA replication: What enzymes are involved? How does this occur? Erase Eukaryotic cells Bacterial cells occursin nucleus occursincytoplasm Transcription makeDNA RNA Eukaryoticcells ceursinnucleus Prokaryoticcells mRNA templatestrandthestrandenzymeusestomake maturemRNA bcwe haveintrons occursin cytoplasm thisispre outviasnRNP's sliced introns hasoneD 5 cap 3 polyadeny tail Translation  What is a mutation? a changeinseqofDNA basepair issubjecttomutation any What type of mutations are there? How do these mutations occur? silentmutation changeone baseincodonbutstillgivessame A A conduit.ie tnohfin n'a i ftp.iiefa.is iiindittatnorteiitiii What is the transformation principle? Why is this important?