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Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik.

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Presentation on theme: "Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik."— Presentation transcript:

1 Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik – , India

2 OC-SBT053-CP1-02 Introduction Programmes and Courses  SEP – SBT053 – Unit 01

3 School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.3 Credits  Academic Inputs by Mrs. Rasika Bhore M.sc (Microbiology)

4 School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.4 How to Use This Resource  Counselor at each study center should use this presentation to deliver lecture of minutes during Face-To-Face counseling.  Discussion about students difficulties or tutorial with assignments should follow the lecture for about minutes.  Handouts (with 6 slides on each A4 size page) of this presentation should be provided to each student.  Each student should discuss on the discussion forum all the terms which could not be understood. This will improve his writing skills and enhance knowledge level about topics, which shall be immensely useful for end exam.  Appear several times, for all the Self-Tests, available for this course.  Student can use handouts for last minutes preparation just before end exam.

5 School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.5 Learning Objectives  After studying this module, you should be able to: Discuss the action of important enzymes in recombinant DNA technology. Describe the application of enzymes & conditions for the action of enzymes.

6 School of Science and Technology, Online Counseling Resource… Introduction  Enzymes are the keys of success of genetic engineering.  Along with restriction enzymes which functions in the cleavage of DNA there are certain enzymes required to rebind it.  These enzymes join the DNA with vector & helps in the formation of recombinant DNA.

7 School of Science and Technology, Online Counseling Resource… S1 Nuclease  S1 nuclease is an endonuclease active against single-stranded DNA and RNA molecules.  It is five times more active on DNA than RNA.  Its reaction products are oligonucleotides or single nucleotides with 5' phosphoryl groups.  Its primary substrate is single-stranded, but also introduce single-stranded breaks in double- stranded DNA or RNA, or DNA-RNA hybrids.

8 School of Science and Technology, Online Counseling Resource… Action of S1 Nuclease

9 School of Science and Technology, Online Counseling Resource… Application of S1 Nuclease  It is used in the laboratory as a reagent in nuclease protection assays.  In Molecular biology it is used in removing single stranded tails from DNA molecules to create blunt ended molecules and opening hairpin loops generated during synthesis of double stranded cDNA.

10 School of Science and Technology, Online Counseling Resource… DNA Ligase  DNA ligases are vital enzymes required for important cellular processes such as DNA replication, repair of damaged DNA and recombination.  The enzyme mediates the formation of phosphodiester bonds between adjacent 3'-OH and 5'-phosphate termini, thereby joining the nicks in double stranded DNA.

11 School of Science and Technology, Online Counseling Resource… Types of DNA Ligases  Ligases can be classified into two groups depending on their requirement for ATP or NAD+ as the cofactor. 1.All eukaryotic and virally encoded enzymes are ATP- dependent. Example- DNA ligase from bacteriophage T7. 2.Most prokaryotic enzymes require NAD + for their activity. Example- DNA ligase from B.stearothermophilus. 3.In mammals, four types of DNA ligases are present.

12 School of Science and Technology, Online Counseling Resource… T4 DNA Ligase  It is used for covalently joining restriction fragments along with E.coli DNA ligase.  E.coli DNA ligase uses NAD + while T4 DNA ligase requires ATP.  T4 DNA ligase has the ability to join the blunt ends of DNA fragment, whereas E.coli DNA ligase joins the cohesive ends produced by restriction enzymes.  T4 enzyme can quickly join & produce the full base pairs.

13 School of Science and Technology, Online Counseling Resource… DNA Ligase In Molecular Biology  DNA ligase has extensive use in molecular biology laboratories for that can link together DNA strands that have double- strand breaks.

14 School of Science and Technology, Online Counseling Resource… Applications of DNA Ligase  DNA ligases are used with restriction enzymes to insert DNA fragments, often genes, into plasmids.  To perform successful recombination experiments ligase is use for controlling the optimal temperature.  Most experiments use T4 DNA Ligase which is most active at 25°C.  In order to perform successful ligations, the optimal enzyme temperature needs to be balanced with the melting temperature Tm & the annealing temperature of the DNA fragments being ligated.

15 School of Science and Technology, Online Counseling Resource… What We Learn………….  S1 nuclease can introduce break in single stranded DNA or RNA.  It acts intensively on DNA than RNA & create blunt ends.  DNA ligase carry out three types of actions repair, replication & recombination.  In molecular biology, their vital role is the ligation of DNA into vector.

16 School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.16 Critical Thinking Questions 1.What is cDNA? 2.What is mean by bacteriophage? Explain the pathway follow by virus for prolonged survival in bacteriophage.

17 School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved. Tips For Critical Thinking Questions 1.DNA formed by virus. 2.Virus in bacteria.Lysogenic pathway.

18 School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.18 Study Tips  Refer the books on Enzymology!   DNA Ligase   DNA Ligase

19 End of the Presentation Thank You


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