biofilms are collecton of microbes

1. “Biofilms”
NAME: Hira Naveed

2. CONTENTS:
• Definition.
• Examples.
• Structure of biofilms.
• Characteristics.
• Formation of biofilms.

3. DEFINITION:
• “It is a collection of microorganisms surrounded by the slime they secrete,
attached to an inert or living surface”
• Usually mixed microbial species (e.g. dental plaque > 700 spp. of bacteria
and archae)
• Biofilms: “cool for bacteria, not cool for humans!”
• It plays a critical role in pathogenesis and cause the nation loss of billion
dollars due to equipment damage

10. STRUCTURE OF THE BIOFILM:
•
• Composed primarily of microbial cells and glycocalyx like matrix .
• heterogeneous arrangement of microbial cells on a solid surface.
• 85%: Matrix (polysaccharides, proteins, nucleic acid & salts)
• 15%: Bacterial cell
• fully hydrated biofilm appears as ‘tower’ or ‘mushroom’

12. CHARACTERISTICS:
• protects the residing bacteria from environmental threats.
• permits trapping of nutrients.
• Bacterial cells in a biofilm community may communicate and exchange
genetic material to acquire new traits

13. FORMATION OF BIOFILM:
STAGE 1:
• Adsorption of inorganic and organic molecules to the solid surface, forming
a thin layer termed as conditioning layer.

14. STAGE 2:
• Adhesion of microbial cells to this layer.
Phase 1 - Transport of microbes to surface.
Phase 2 - Initial non specific microbial-substrate adherence.
Phase 3 - Specific microbial-substrate adherence phase

15. STAGE 3:
• Bacterial growth and expansion.
• Monolayer of microbes attracts secondary colonizers forming micro colony, and
the collection of micro colonies gives rise to the final structure of biofilm.

16. STAGE 4 :
• Due to any kind of threat , it starts to tear the layer in which they are covered
leading to release of inside cells.
• During detachment, the biofilm transfer particulate constituents from the
biofilm to the fluid bathing the biofilm.

17. .