bacterial genetics.ppt teaching
DESCRIPTION
Bacterial genetics.BasicsTRANSCRIPT
![Page 1: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/1.jpg)
Bacterial GeneticsLearning the Basics
1
Dr.T.V.Rao MD
Dr.T.V.Rao MD
![Page 2: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/2.jpg)
Genetics Guide Life
2Dr.T.V.Rao MD
![Page 3: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/3.jpg)
Genes are EternalRun In Progeny
3Dr.T.V.Rao MD
![Page 4: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/4.jpg)
Understanding Genetics
We resemble and differ because of Genetic configurations
Parents - Son - Daughter, how they resemble each other.
They breed true from Generation to Generation
But vary in small proportions in progeny.
Bacteria too obey the laws of Genetics
T.V.Rao MD
4Dr.T.V.Rao MD
![Page 5: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/5.jpg)
Watson - CrickDiscovery of DNA
5Dr.T.V.Rao MD
![Page 6: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/6.jpg)
Beginning of Bacterial Genetics
• The principles of Genetics were applied to bacteria and viruses
• Advances in Genetic process also of lead to fundamental advances in Biology and Biochemistry.
A Birth of New Branch of Science
Molecular Biology 6Dr.T.V.Rao MD
![Page 7: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/7.jpg)
DNA A Complex Structure
Makes Life
7Dr.T.V.Rao MD
![Page 8: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/8.jpg)
DNA( Deoxyribonucleic Acid )
• DNA is composed of Many Units of
Adenine – Thymine A – T
Guanine – Cytosine G - C
A+ T
G+C proportion differ for each species
DNA replicates first unwinding at one end to form a fork
Each strand of fork acting as template for the synthesis of complementary strand
8Dr.T.V.Rao MD
![Page 9: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/9.jpg)
9Dr.T.V.Rao MD
![Page 10: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/10.jpg)
Structure of DNA
10Dr.T.V.Rao MD
![Page 11: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/11.jpg)
DNA• A DNA molecule is
composed of two chains of Nucleotides wound together in the form of a Double Helix
• Each chain has back bone of Deoxyribose and Phosphates residues arranged alternatively
T.V.Rao MD
11Dr.T.V.Rao MD
![Page 12: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/12.jpg)
Structure of DNA• Attached to each
Deoxyribose and phosphate residues arranged alternatively
• Attached to each Deoxyribose are of four nitrogen bases
• Purines - Adenine, Guanine
• Pyramidine
Thymidine and Cytosine
12Dr.T.V.Rao MD
![Page 13: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/13.jpg)
How RNA differs from DNA
• RNA contains - Sugar Ribose instead of Deoxyribose
• Uracil is present instead of Thymine• Types of RNA Messenger RNA mRNA
Ribosomal RNA rRNA Transfer RNA tRNA 13Dr.T.V.Rao MD
![Page 14: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/14.jpg)
DNA - RNA
14Dr.T.V.Rao MD
![Page 15: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/15.jpg)
Knowledge on DNA lead to advances in Molecular Biology
• Central dogma of Life – Deoxyribonucleic acid• DNA carries the Genetic information• DNA is transcribed to RNA – Polypeptides
Cell Function depends upon specific polypeptides – Proteins – Enzymes
DNA is a store house of Protein synthesis
DNA acts a Template for synthesis of mRNA
Virus differs from other as they contains either DNA or RNA
15Dr.T.V.Rao MD
![Page 16: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/16.jpg)
What is a Code in Genetics
• Code is a unit consists of sequence of three Bases
• Code is triplet A-T- C• A code can make single Amino acid• More than one code present for making similar
sequence of Amino acid• AGA make Arginine• AGC, CGU, CGG, also code for similar Amino
acid• Some Codons UAA don't code for any Amino
acid called as Nonsense codon 16Dr.T.V.Rao MD
![Page 17: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/17.jpg)
What is a Gene• Gene is a sequence
of DNA carrying codons specifying for particular polypeptide.
• DNA contains many Genes( A combinations of hundreds and thousands of Nucleotides )
17Dr.T.V.Rao MD
![Page 18: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/18.jpg)
Bacterial Chromosome
• Contains a Double stranded molecules of DNA arranged in circular form.
• Length 1,ooo microns.• Bacterial DNA contains about
4,000kilobases• I kb = 1000 base pairs ( A-T ) ( G-C)• Humans have about 3,000 kb pairs.
18Dr.T.V.Rao MD
![Page 19: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/19.jpg)
How bacterial Genome differs from Higher forms of Life
• Several stretches of DNA don't appear to function as codons, occurs between the coding sequences of Gene. called as INTRONS.
• Coded are called as EXONS• In transcription introns are excised when
form RNA before translated by ribosomal proteins.
19Dr.T.V.Rao MD
![Page 20: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/20.jpg)
Extra chromosomal Genetic Elements
Bacteria posses Extra chromosomal genetic elements
Not Essential for survival of Bacteria
But makes the Bacteria Resistant to antibiotics, and makes them survive
Able to produce toxins
20Dr.T.V.Rao MD
![Page 21: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/21.jpg)
Plasmids
• Plasmids are circular DNA molecules present in the cytoplasm of the Bacteria
• Capable of Autonomous replication
• Can transfer genes from one cell to other
• Act as vectors in Genetic engineering.
• Can also present in Yeasts
21Dr.T.V.Rao MD
![Page 22: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/22.jpg)
Plasmid ( Blue )
22Dr.T.V.Rao MD
![Page 23: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/23.jpg)
Plasmids • Plasmid seem to be ubiquitous in bacteria, May
encode genetic information for properties
1 Resistance to Antibiotics 2 Bacteriocins production 3 Enterotoxin production 4 Enhanced pathogen city 5 Reduced Sensitivity to mutagens 6 Degrade complex organic molecules
T.V.Rao MD
23Dr.T.V.Rao MD
![Page 24: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/24.jpg)
R plasmid
R: drug resistance
RTF: transfer of R plasmid
24Dr.T.V.Rao MD
![Page 25: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/25.jpg)
Plasmids
• Can be integrated with Chromosomal DNA
• Episomes -Integrated form of plasmid with DNA
25Dr.T.V.Rao MD
![Page 26: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/26.jpg)
Potentials of Plasmids
• Plasmids can be self transmissible and Non transmissible
• Transfers the Sex and Drug resistance with the help of restriction end nucleases
26Dr.T.V.Rao MD
![Page 27: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/27.jpg)
Classification of Plasmids
• Incompatibility typing• Don't accommodate
others which are similar
• Other methods of Classification
Centrifugation
Electrophoresis
Genetic methods
27Dr.T.V.Rao MD
![Page 28: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/28.jpg)
Genotypic and Phenotypic variation
• Genome – Sum total of Gene that make up the genetic apparatus of cell established as Genotype.
• Hereditary constitution of cell this transmitted to its progeny
• Phenotype – is the physical expression in a environment. Change according to environment.
28Dr.T.V.Rao MD
![Page 29: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/29.jpg)
What is Phenotypic expression
• Exhibit – different phenotypes• Appearance differs in different situations.• Eg Typhoid bacilli flagellated normally• But grown in Phenol agar don't grow flagella So
flagella are lost physical variation• Lactose fermentation in E.coli dependent on
Beta Galactosidase
When lactose present - test is positive
When lactose is absent - test turns negative
29Dr.T.V.Rao MD
![Page 30: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/30.jpg)
Different Enzymes Guided by Genomic configurations
• Inducer enzyme acts in the presence of substrate
• Constitutive enzyme acts irrespective of presence or absence of enzyme.
• Phenotypic variations influenced by environment limited in range by genes
• Genotypic variations are stable not influenced by environment.
T.V.Rao MD
30Dr.T.V.Rao MD
![Page 31: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/31.jpg)
Principles of Genotypic variations
• Mutations• Genotypic by transfer of genes
Transformation
Transduction
(Lysogenic conversion)
Conjugation31Dr.T.V.Rao MD
![Page 32: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/32.jpg)
Replica Plating, pt. 2
32Dr.T.V.Rao MD
![Page 33: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/33.jpg)
Mutations in Bacteria• Bacteria Multiply by asexual binary fission• Altered Nucleotide sequence in expresses new
or altered characteristics • Selective value to the organism• Evolutionary value• Acquires Antibiotic resistance grows in body
without inhibition• Become a prominent organism• Phenotypic variation occurs when genes
changes in response to the environment but reversible.
T.V.Rao MD 33Dr.T.V.Rao MD
![Page 34: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/34.jpg)
Mutations
• Mutation is a Random, Undirected, Heritable variation
• Caused by alteration in the Nucleotide sequence at some point of DNA which can occur due to
Addition Deletion Substitution of one or more bases
34Dr.T.V.Rao MD
![Page 35: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/35.jpg)
Mutation Type
Frameshift (deletion) (leu) (ser) (arg)
Normal AAT AGT GCC
(leu) (val) (pro)
Mutant AAT AGT GCC A
35Dr.T.V.Rao MD
![Page 36: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/36.jpg)
Mutation Type
Frameshift (insertion) (leu) (ser) (arg)
Normal AAT AGT GCC
(leu) (glut) (cyst)
Mutant AAT CAGT GCC
36Dr.T.V.Rao MD
![Page 37: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/37.jpg)
37Dr.T.V.Rao MD
![Page 38: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/38.jpg)
Mutations can occur in any sequence,inveitable, useful for
Survival
38Dr.T.V.Rao MD
![Page 39: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/39.jpg)
Multiple Mutations• Causes extensive chromosomal rearrangement• Missense mutation -Triplet code is acted so as
to specify an Aminoacid different from that normally located at particular position in the protein
• Nonsense mutation - Deletion of nucleotide within a gene may cause premature polypeptide chain termination by nonsense codon
• Tran version is Substitution of purine for pyramidine or vice versa in the base pairing
39Dr.T.V.Rao MD
![Page 40: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/40.jpg)
Mutations
• Suppressor Mutation is reversal of mutant phenotype by another mutation at a point of DNA distant from that of original mutation.
• All genes are susceptible for mutations, but all mutations are not expressed
• Lethal mutation is harmful destroy the vital functions
40Dr.T.V.Rao MD
![Page 41: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/41.jpg)
Mutations
• Conditional Lethal mutant may be Live under certain conditions
• Common example is temperature ( its ) mutant• Temp sensitive ( ts) mutant lives at 350c but not
at 390c• Each gene undergoes mutation at a fixed
frequency.
Bacteria undergo mutations at 10-4 - to 10-10
• Tutomerisim T – A is replaced by G - A
41Dr.T.V.Rao MD
![Page 42: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/42.jpg)
Mutagenic Agents
• U V rays• Alkyl ting
agents• Arcidine Dyes
42Dr.T.V.Rao MD
![Page 43: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/43.jpg)
GENE TRANSFER Occurs by Complex Mechanisms
43Dr.T.V.Rao MD
![Page 44: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/44.jpg)
The three bacterial sexual processes
– 1. Conjugation: direct transfer of DNA from one bacterial cell to another.
–2. Transduction: use of a Bacteriophages (bacterial virus) to transfer DNA between cells.
–3. Transformation: naked DNA is taken up from the environment by bacterial cells. 44Dr.T.V.Rao MD
![Page 45: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/45.jpg)
Transformation of Genetic material
( Gene Transfer )
• Different Mechanisms Transformation
Transduction
Conjugation
45Dr.T.V.Rao MD
![Page 46: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/46.jpg)
Gene Transfer Processes for Bacteria and Their Viruses
1. Conjugation2. Transformation
3. Transduction
4. Infection with bacteriophage
46Dr.T.V.Rao MD
![Page 47: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/47.jpg)
What is Transformation• Transformation is defined as transfer of Genetic
information through the activity of DNA• Griffith experiment Mice injected with Live non capsulated ( R )
Pneumococci with heat killed capsulated (S) Pneumococci
Lead to death of Mice with isolation of Live
capsulated Pneumococci It means that some factor from Dead
pneumococci transferred to live non pathogenic Pneumococci
Avery, McCleod, Mc Cartny in 1944 identified to be DNA47Dr.T.V.Rao MD
![Page 48: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/48.jpg)
Griffith Phenomenon
48Dr.T.V.Rao MD
![Page 49: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/49.jpg)
Demonstration of transformation
Avery, MacLeod, and McCarty (1944)
49Dr.T.V.Rao MD
![Page 50: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/50.jpg)
Transduction
• Generalized involve any segment of DNA
• Restricted when specific Bacteriophages traduces only a particular genetic trait.
• Transduction effects Plasmids ,and Episomes• Plasmid transfer induces Penicillin resistance in
Staphylococcus• Helps Genetic mapping, also in eukaryotic cell• Helps Genetic Engineering T.V.Rao MD
50Dr.T.V.Rao MD
![Page 51: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/51.jpg)
Transduction• Transduction is
defined as transfer of portion of DNA from one bacteria to another by Bacteriophages, is known as Transduction
T.V.Rao MD
51Dr.T.V.Rao MD
![Page 52: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/52.jpg)
DNA transfer through Bacteriophages
• When the Phage particle infects another bacteria DNA transfer is effected and the recipient cell acquires new characters coded by donor DNA
52Dr.T.V.Rao MD
![Page 53: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/53.jpg)
Bacteriophages
• Are viruses that parasitize bacteria and consists of Nucleic acid core and a protein coat
• A phage particle may have at its core besides its own nucleic acid and a segment of the Host DNA 53Dr.T.V.Rao MD
![Page 54: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/54.jpg)
Transduction Types
• Two types of Transduction• 1 Lytic and 2 Lysogenic• 1 Virulent or Lytic cycle after
large number of progeny are built up inside the host bacterium ruptures and phages are released 54Dr.T.V.Rao MD
![Page 55: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/55.jpg)
Lysogenicity creates new characters
• Eg - Lysogenic conversion in Diphtheria bacilli which acquires toxigenicity by lysogenization with phage beta
• Elimination of phage for toxigenic strain renders nontoxigenic
T.V.Rao MD
55Dr.T.V.Rao MD
![Page 56: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/56.jpg)
ConjugationLederberg - Tatum
• A process by which a Donor cell or male cell makes contact with another cell, the recipient or Female cell.
• DNA is directly transferable• Plasmid Carry genetic information necessary for
conjugation to occur.• Only cell that contain such plasmids can act as
donor. the cell lacking a corresponding plasmid act as recipient.
• Requires direct contact between donor and recipient
T.V.Rao MD
56Dr.T.V.Rao MD
![Page 57: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/57.jpg)
Conjugation
• The ability to conjugate is conferred by the F plasmid. A plasmid is a small circle of DNA that replicates independently of the chromosome. Bacterial cells that contain an F plasmid are called “F+”. Bacteria that don’t have an F plasmid are called “ 57Dr.T.V.Rao MD
![Page 58: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/58.jpg)
Conjugation - Transferring genes with plasmids
• Plasmids mediating conjugation carry genes coding for properties, of 1-2 microns long protein appendage termed Pilus on the Donor cell
58Dr.T.V.Rao MD
![Page 59: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/59.jpg)
Mechanism of Transfer I:Conjugation
59Dr.T.V.Rao MD
![Page 60: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/60.jpg)
Conjugation
60Dr.T.V.Rao MD
![Page 61: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/61.jpg)
Simple Conjugation
61Dr.T.V.Rao MD
![Page 62: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/62.jpg)
Conjugation
62Dr.T.V.Rao MD
![Page 63: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/63.jpg)
Pilus helps Conjugation
• Different types of Pilus are specified by different types of plasmids and can help in aid of plasmid classification.
• Only one strand of circular DNA of the plasmid nicked upon at a specific site and passed into a recipient.
• Spread to all other cells.
63Dr.T.V.Rao MD
![Page 64: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/64.jpg)
F factor
• Transfer factor that contains the genetic information necessary for synthesis of Sex Pilus and for self transfer without any other identifiable genetic materials such as drug resistance
T.V.Rao MD64Dr.T.V.Rao MD
![Page 65: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/65.jpg)
F factor helps transformation
• F+ called as Donor bacteria can transform F- into F+ cell Can be Episomes able to exist in some cells in the
integrated state in the donor cell chromosome Can transform chromosomal genes to recruitment with
high frequency are known as Hfr cells Conversion of F+ cells into Hfr state is reversible. F factor incorporates some chromosomal genes and is
called as F’ Sexduction The process of transfer of host genes
through F’ factor
65Dr.T.V.Rao MD
![Page 66: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/66.jpg)
DNA transfer through Bacteriophages
• When the Phage particle infects another bacteria DNA transfer is effected and the recipient cell acquires new characters coded by donor DNA
66Dr.T.V.Rao MD
![Page 67: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/67.jpg)
Types of DNA transfer throughBacteriophages
67Dr.T.V.Rao MD
![Page 68: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/68.jpg)
Colicinogenic ( Col ) Factor
• Coli form Bacteria produce Colicins
• Colicins are lethal to other Enterobacteriaceae
• Pyocins produce by Pseudomonas
• Diptherocins produced by C.diptheria
• Plasmid transmits col factor leads to self transfer of chromosomal segments
T.V.Rao MD 68Dr.T.V.Rao MD
![Page 69: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/69.jpg)
Resistance Transfer FactorRTF
• Plasmids – helps to spread multiple drug resistance
• Discovered in 1959 Japan• Infections caused due to Shigella spread
resistance to following Antibiotics
Sulphonamides
Streptomycin
Chloramphenicol,
Tetracycline69Dr.T.V.Rao MD
![Page 70: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/70.jpg)
RTF
• Shigella + E.coli excreted in the stool resistant to several drugs in vivo and vitro
• Plasmid mediated –transmitted by Conjugation
• Episomes spread the resistance
70Dr.T.V.Rao MD
![Page 71: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/71.jpg)
Bacterial Conjugation:High Frequency Transfer (Her) Cells
71Dr.T.V.Rao MD
![Page 72: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/72.jpg)
Hfr Conjugation
72Dr.T.V.Rao MD
![Page 73: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/73.jpg)
Sequence of RTF transmission
73Dr.T.V.Rao MD
![Page 74: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/74.jpg)
Hfr cell conjugating a Normal cell
74Dr.T.V.Rao MD
![Page 75: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/75.jpg)
Composition of RTF• Plasmid consists of two
components• A transfer factor RT, helps
conjugational transfer and resistant determinants ( r ) to each of the several drugs
• RTF + r determinants are known as R factor
75Dr.T.V.Rao MD
![Page 76: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/76.jpg)
R factor• R factor can contain
several determinants as many as 8 or > 8 drugs
• Guide the cell for production of Enterotoxins too
• But R factors can be inhibited by
Bile salts
R factors can be transferred to animals
76Dr.T.V.Rao MD
![Page 77: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/77.jpg)
Genesis of R factors
• In discriminate use of Antibiotics in vet nary Medicine has increased the spread of R factors to Human
• Addition of Antibiotics to Animal feeds to be prohibited.
77Dr.T.V.Rao MD
![Page 78: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/78.jpg)
Genetic Mechanisms of Drug Resistance
• Bacteria acquire drug resistance through several Mechanisms
• Mutations• Genetic transfer Transformation, Transduction ConjugationSeveral Biochemical Mechanisms Decreasing permeability of drugs, Attaining alternative pathways Produce enzymes and inactivate drugs
78Dr.T.V.Rao MD
![Page 79: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/79.jpg)
Genetic Mechanisms in Bacteria helps to Spread the Infectious diseases
79Dr.T.V.Rao MD
![Page 80: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/80.jpg)
Mutations• Mutilations can be
1 Stepwise mutation as in Penicillin use
2 One step mutation
Streptomycin use
May show low resistance or High resistance
If tuberculosis is treated with sole drug as of Only Streptomycin some resistant mutants appear and replaces sensitive bacteria in due course
so the occurrence of MDR - TB80Dr.T.V.Rao MD
![Page 81: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/81.jpg)
Other Mechanisms
• Use of Penicillin created resistant Staphylococcus by transduction
• R factors created resistance to several drugs, caused increased virulence
• Spread to several humans and animals
Best option- To restrict use of
Antibiotics81Dr.T.V.Rao MD
![Page 82: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/82.jpg)
Transposable Genetic Elements Structurally / Genetically – Discrete sequence of
DNA – Move around in a cut and paste manner between Chromosomal and Extra chromosomal DNA molecules within cells.
Called as Transposons _ Jumping GenesGenetic transfer due to TranspositionSmall Transposons 1 – 2 KbNot self replicating and depend on Plasmid or
Chromosome for replication.A chunk of DNA is added by Transposons.
82Dr.T.V.Rao MD
![Page 83: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/83.jpg)
Transposons and R factor
• R forms may have evolved as a collection of Transposons
• Each carrying Genes that confers resistance to one or several Antibiotics
• Seen in Plasmids, Microorganisms AnimalsLaboratory Manipulations are called as Genetic
Engineering
83Dr.T.V.Rao MD
![Page 84: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/84.jpg)
Molecular Genetics
• Analysis and manipulation of DNA using Biochemical and Microbiological techniques
84Dr.T.V.Rao MD
![Page 85: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/85.jpg)
Genetic Engineering
• Under standing Molecular genetics in Biochemistry fuels genetic Engineering
• Recombinant DNA (renal) techniques changed the ideals of Medicine
• Genetic Engineering await many surprises?
85Dr.T.V.Rao MD
![Page 86: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/86.jpg)
Genetic Engineering Was Born from Genetic Recombination•Genetic engineering involves changing the genetic material in an organism to alter its traits or products
•A recombinant DNA molecule contains DNA fragments spliced together from 2 or more organisms
Genetic Engineering
86Dr.T.V.Rao MD
![Page 87: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/87.jpg)
Modern applications
• Pharmaceutical production– Insulin, interferon, hormones, vaccines
etc.• Genetically engineered plants• Animal gene alterations• Gene probes• DNA fingerprinting• The human genome initiative
Dr.T.V.Rao MD 87
![Page 88: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/88.jpg)
Genetic Engineering
• Isolation of Genes coding for any desired protein from Microorganism or from cell of higher life forms including human beings and their introduction into a suitable microorganism in which genes would function directing the production of specific proteins
88Dr.T.V.Rao MD
![Page 89: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/89.jpg)
Genetic Engineering changing the Diagnostic and Therapeutic
Protocols in MEDICINE
89Dr.T.V.Rao MD
![Page 90: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/90.jpg)
Research on Gene transfer shapes the future of Science
90Dr.T.V.Rao MD
![Page 91: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/91.jpg)
Genetically Engineered Products
• Can prepare desired protein in pure form in economic way
Somatostatin• Commercial
preparations pdf Cloned Human
Insulin Interferons
Hepatitis B vaccine
91Dr.T.V.Rao MD
![Page 92: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/92.jpg)
Restriction Endonucleases
• A restriction enzyme (or restriction endonuclease) is an enzyme that cuts
double-stranded DNA. The enzyme makes two incisions, one through each of the sugar-phosphate backbones (i.e., each strand) of the double helix without
damaging the nitrogenous bases They work with cutting up foreign DNA, a process called
92Dr.T.V.Rao MD
![Page 93: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/93.jpg)
Restriction EndonucleasesMade the advances in Genetic
Engineering
93Dr.T.V.Rao MD
![Page 94: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/94.jpg)
DNA Probes
• There are Radioactive Biotinylated otherwise
labeled copies united single stranded DNA
Contains 20 -25 nucleotides Helps detection of
Homology DNA by Hybridization.
Helps Diagnosis of Infectious Diseases
Minute quantities of DNA can be detected.
94Dr.T.V.Rao MD
![Page 95: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/95.jpg)
Blotting Techniques
• Drug fragments obtained by restriction enzyme digestion on separation Gel can be transferred to Nitrocellulose or nylon membranes
• Several methods 1 Southern blotting 2 Northern Blotting 3 Western blotting
95Dr.T.V.Rao MD
![Page 96: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/96.jpg)
western blot• The western blot (alternatively, protein
immunoblot) is an analytical technique used to detect specific proteins in a given sample of tissue homogenate or extract. It uses gel electrophoresis to separate native or denatured proteins by the length of the polypeptide (denaturing conditions) or by the 3-D structure of the protein (native/ non-denaturing conditions)
96Dr.T.V.Rao MD
![Page 97: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/97.jpg)
Western Blotting
• In Western Blot Protein ( Antigen ) mixture is separated by SDS ( Sodium dodecyl sulfate – polyacrylamide gel electrophoresis ) Blotted on to Nitro cellulose strips and identified by radio labeled or enzyme labeled antibodies as probes
97Dr.T.V.Rao MD
![Page 98: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/98.jpg)
Western Blot
98Dr.T.V.Rao MD
![Page 99: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/99.jpg)
Western Blot to confirmHIV Infections made land mark
Diagnostic tool• Western Blot testing
is confirmatory test for diagnosis of HIV/AIDS
• Identifies antibodies directed against different antigens in pathogen
Surface,
Core
RT antigen 99Dr.T.V.Rao MD
![Page 100: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/100.jpg)
Polymerase chain reactionKary B Mullis 1983
• Rapid• Automatic
amplification of specific DNA sequences
• Nobel prize winning Technology 1993
100Dr.T.V.Rao MD
![Page 101: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/101.jpg)
PCR -Sequences
• PCR consists of several cycles of sequential DNA replication where the products of first cycle becomes the template for the Next
• It makes available abundant quantities of specific DNA sequences starting
101Dr.T.V.Rao MD
![Page 102: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/102.jpg)
Genetic Mapping
• Genetic sequences for Bacteriophages and virus
• Genetic mapping is done most of the Human Genes
102Dr.T.V.Rao MD
![Page 103: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/103.jpg)
Newer Understanding on GENES
103Dr.T.V.Rao MD
![Page 104: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/104.jpg)
Human Genome Project
104Dr.T.V.Rao MD
![Page 105: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/105.jpg)
Human Genome Project
• Completed in 2003, the Human Genome Project (HGP) was a 13-year project coordinated by the U.S. Department of Energy and the National Institutes of Health. During the early years of the HGP, the Welcome Trust (U.K.) became a major partner; additional contributions came from Japan, France, Germany, China, and others
105Dr.T.V.Rao MD
![Page 106: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/106.jpg)
Genetics are Complex - Leading the birth of BIOINFORMATICS
106Dr.T.V.Rao MD
![Page 107: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/107.jpg)
Genes Evolved and made us Men
What NEXT ?
107Dr.T.V.Rao MD
![Page 108: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/108.jpg)
Are We Playing with Genes in the Right Direction ?
108Dr.T.V.Rao MD
![Page 109: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/109.jpg)
Understanding of human Genome is Changing the Future of Medicine
109Dr.T.V.Rao MD
![Page 110: Bacterial genetics.ppt teaching](https://reader033.vdocuments.site/reader033/viewer/2022042601/554b185db4c90562098b4eee/html5/thumbnails/110.jpg)
• Programmed Created by Dr.T.V.Rao MD for Undergraduate Medical Students in
the Developing World • Email
110Dr.T.V.Rao MD