Bacteriophage are viruses that infect bacteria. They have either DNA or RNA genomes surrounded by a protein capsid. Bacteriophage were discovered in the late 19th/early 20th century and have been classified into 13 families based on their structure and genetics. They have complex lifecycles involving either lytic cycles where the host cell is lysed or lysogenic cycles where the viral genome integrates with the host DNA. Bacteriophage are the most abundant biological entity and play important ecological roles.

1. GOVT.PG ART’S AND SCIENCE
COLLEGE RATLAM (M.P)
2017-2018
MS.c 2nd SEMESTER
(MICROBIOLOGY)
PAPER – VIRUS
SUBBMITTED TO: SUBBMITTED
BY:
KANUPRIYA MANORAMA
MAM CHAUDHARY

2. BACTERIOPHAGE

3. INDEX
 INTRODUCTION
 HISTORY
 FEATURES
 STRUCTURES
 BIOCHEMICAL NATURE
 CLASSIFICATION
 MORPHOLOGICAL TYPES
 MULTIPLICATION CYCLE
 LYTIC CYCLE
 LYSOGENY CYCLE
 REFERENCE

4. INTRODUCTION
• A virus that infects bacteria and Replicates
within a bacterium.
• The word Bacteriophage Derived from
"bacteria" and phagein, "to devour".
• It may be Single or double-stranded
• They are Surrounded by protein capsid.
• Genomes may encode as few as four
genes, and as many as hundreds of genes.

5. HISTORY
 A century ago, Hankin (1896) reported that the
waters of the Ganges and Jumna rivers in India
had marked antibacterial action (against Vibrio
cholerae, restrict epidemic) which could pass
through a very fine porcelain filter; this activity was
destroyed by boiling.
 Edward Twort (1915) and Felix d'Herelle (1917)
independently reported isolating filterable entities
capable of destroying bacterial cultures and of
producing small cleared areas on bacterial lawns.
 It was F d'Herelle, a Canadian working at the
Pasteur Institute in Paris, who gave them the
name "bacteriophages"-- using the suffix phage
(1922).

6. FEATURES
 Most abundently found
virus species.
 Specific bacteriophage
attacks specific Bacteria
and Archea.
 Their genomes can be
highely mosaic.
 They are excellent
examples of optimisation
of genetic information to
carry out complex
functions.

7. STRUCTURE OF
BACTERIOPHAGE
Structure of Bacteriophage Consist of
3
Main parts :
1) Head
2) Neck
3) Tail

8. STRUCTURE OF
BACTERIOPHAGE

9. BIOCHEMICAL NATURE
1)NUCLEIC ACID:
- Center DNA/ RNA
- DNA/ RNA Bacteriophage may have double or
single stranded
- Linear or Circular
2) PROTEIN :
- Nucleic acid is covered by a protein coat called
Capsid . The no. of protomers may differ from types.
3)LIPIDS :
- All Enveloped Bacteriophage Have Lipids,
Phospholipids ,Glycolipid.

10. CLASSIFICATION OF
BACTERIOPHAGE
Bacteriophage were classified in 13
families on the basis of :
 Nucleic acid
 Strands of nucleic acid
 Morphology
 Genome

11. CLASSIFICATION

12. Diagrammtic repersentation of
classification

13. MORPHOLOGICAL TYPES
On The basis of ELECTRON
MICROSCOPE STUDIES, BRADLEY
(1967) has described the following
six Morphological types of
Bacateriophage

14. MORPHOLOGICAL TYPES
1) TYPE A: Hexagonal head , Rigid tail,
EG: dsRNA T2,T4
2) TYPE B: Hexagonal head, Lack
contractile
sheath, Flexible tail.
EG: dsDNA T1T3T5
3) TYPE C: Hexagonal head, Contractile
sheath
absent. Tail maybe shorter.

15. SHAPES OF MORPHOLOGICAL
TYPES

16. MORPHPOLOGICAL
TYPES
4) TYPE D: Head made of capsomeare,
Tail abesnt
EG:ssDNA
5) TYPE E: Head is made of small capsomer,
Tail absent
EG: ssRNA PHAGE
6)TYPE F: Filamentous phage, Lipid envelope,
Attack some
plant.
EG: ssDNA PHAGE

17. MULTIPLICATION CYCLE
Multiplication cycle of Bacteriophage
complete in 5 steps:
1) ADSORPTION
2) PENETRATION
3) SYNTHESIS OF PHAGE
COMPONENTS
4) MATURATION & ASSEMBLY
5) RELESAS

18. MULTIPLICATIION CYCLE

19. LYTIC CYCLE
 The viral genome does not integrated with
host DNA.
 The host DNA is often hydrolysed in the lytic
phage .
 The virus is virulent.
 The host cell under goes lysis.
 A no. Of virus particle are liberated when
the host cell become lysed.

20. LYSOGENYE CYCLE
 The viral genome or its complementery
DNA gets integrated with the host DNA.
 The host DNA donot hydrolysed. During
lysogenic phage.
 The celluar machinery of the host is only
slightly diturbed.
 The host cell does not get lysed.
 Virus particle are liberated rarely.

22. REFERENCE
 Luria,E.E,Darnell,J.E.Jr.,Baltimore,D.and
Campbell,A.(1978).General Viorology III ed. Johan
Wiley and Sons. New york.
 Madigan, M.T.,Martinko,J.M. and Parker, J.(2000)
Brock Biology of microorganism, Prentice hall
International inc.
 Brown ,T.A. (1999). Genome .IV.ed . John Wiley
and sons.
 Black,J.G.(2002) Microbiology- Principles and
Exploration. V ed . John Wiley &sons
 Prescott,L.M, Harley,J.P. and Klein, D.A.(2000)
Microbiology VIII ed.John Wiley & sons,inc

23. THE END