Lecture On Bacterial Genetics & Horizontal Gene Transfer (Microbiology Lecture) | MBBS | TSMC

Описание: This essential 40-minute lecture by Dr. Debasree Saha (TSMC) is a comprehensive guide to Bacterial Genetics, a critical subject for students in Microbiology, Molecular Biology, and Infectious Diseases.

Master the structure of Bacterial DNA (Supercoiling, Nucleoid), the role of Plasmids (F-factor, R-factor), and the primary mechanisms of horizontal gene transfer: Transformation (uptake of naked DNA), Transduction (via bacteriophage), and Conjugation (cell-to-cell contact). The lecture also details the experimental evidence (Griffith's Experiment) and the critical link between these processes and Antibiotic Drug Resistance.

Lecture Topics & Timestamps for Study:

Use the timestamps to quickly navigate to the sections most relevant to your studies:

[00:50] Bacterial DNA Structure: Single, circular, supercoiled, double-stranded DNA; Nucleoid region.

[01:58] DNA Supercoiling: Negative (Eubacteria) vs. Positive (Thermophilic Archaebacteria).

[03:47] DNA Replication: Bi-directional Replication (E. coli) and Rolling Circle Mechanism (Conjugation).

[05:01] Replication Enzymes: Function of Helicase, Topoisomerase, DNA Polymerase (I, II, III), and Ligase.

[05:51] Protein Synthesis: Central Dogma (Transcription & Translation), Codons (Sense/Nonsense), and the stages of translation.

[08:28] Plasmids: Definition, structure (extra-chromosomal circular DNA), and Episomes (integrated plasmids).

[09:39] Curing: Process of eliminating plasmids.

[11:00] Classification of Plasmids: Conjugative/Non-conjugative, Fertility (F) Factor, Resistance (R) Factor (Drug Resistance), Col Plasmids (Bacteriocin), and Virulence Plasmids.

[13:47] Genetic Variation: Mutation (Spontaneous & Induced) and Horizontal Gene Transfer.

[16:19] Types of Mutation: Point Mutation (Transition/Transversion), Frameshift Mutation, and Suppressor Mutation.

[18:22] Detecting Mutants: Genotypic (Sequencing) and Phenotypic Methods (Ames Test).

[19:39] Horizontal Gene Transfer (HGT) Mechanisms:

[19:42] 1. Transformation: Random uptake of Naked DNA from the environment.

[22:37] Griffith's Experiment: Direct evidence of Transformation using Streptococcus pneumoniae (S and R strains).

[24:54] 2. Transduction: DNA transfer mediated by a Bacteriophage.

[25:32] Phage Life Cycles: Lytic/Virulent Cycle and Lysogenic/Temperate Cycle.

[26:36] Types of Transduction: Generalized (any part of genome) and Restricted/Specialized (adjacent segment only).

[30:13] Lysogenic Conversion: Acquisition of new virulence factors (e.g., Diphtheria Toxin or Cholera Toxin genes are phage-coded).

[31:32] 3. Conjugation: Genetic transfer via cell-to-cell contact and Conjugation Tube (Mating).

[32:08] F+ to F- Cell Transfer (F- becomes F+).

[33:14] Hfr Conjugation: High-Frequency Recombination (integrated F factor).

[35:00] Role in Drug Resistance: Transfer of the R-Factor (plasmid coding for multiple drug resistance).

[36:11] 4. Transposition: Transfer of mobile genetic elements (Transposons) within and between DNA molecules ("Jumping Genes").

[37:37] Genetic Engineering & Recombinant DNA Technology: Overview of applications (vaccines, gene therapy) and blotting techniques.

Keywords & Hashtags for Maximum Reach:

Primary Keywords: Bacterial Genetics, Horizontal Gene Transfer, Transformation, Transduction, Conjugation, Plasmids, Antibiotic Resistance.

Secondary Keywords: Griffith's Experiment, Bacteriophage, Lysogenic Conversion, R-Factor, Transposons, Diphtheria Toxin, Hfr Conjugation, Microbiology Lecture.

#BacterialGenetics #Microbiology #HorizontalGeneTransfer #Transformation #Transduction#TSMC


TRIPURA SANTINIKETAN MEDICAL COLLEGE & HOSPITAL
Real Classroom Demonstration/
MICROBIOLOGY LECTURE ON- BACTERIAL GENETICS. BY-DR. DEBASREE SAHA
(MBBS Batch: 2024-25)
Conducted on: 14-11-25