FLAGELLA. an overview of bacterial flagella

Bacterial flagella

1. FLAGELLA

2. Flagella are microscopic hair like structure involved in the locomotion of a cell. The word “ Flagellam”means “whip”. Because the flagella have a whip-like appearance that helps to propel a cell through the liquid. Some special flagella are used in few organisms as sensory organs that can sense changes in PH and temperature. The are filamentous structures found in Archie Bactria Eukaryotes

3. Arche fegella This are non homologous Eukaryotic fegella This are complicated cellular projections that pummel backwards and forward and are found in protests cells, gametes of plates and animals. it is made up f protein called tubulin.

4. 3. Bacterial flagella are coiled thread-like structure, sharp bent,consisiting of a rotary motor at its base and are composed of the protein flagellin . A shaft exists between a hook and a basal body passing through the protein rings in the cell membrane Bacterial flagella refer to the locomotory apparatus. Has 3-5 micrometer length & 0.001-0.013 micrometer thickness The bacterial possessing flagella are the motile organisms or non flagellates lack flagella The location, number and arrangement of flagella, vary considerably in different bacterial species Flagella has 15-20nm diameter and can be seen Ander a light microscope

5. TYPES OF FLAGELLA ATRICHOUS MONOTRICHOUS AMPHITRICHOUS LOPHOTRICHOUS PERITRICHOUS CEPHALO TRICHOUS

6. ATRICHOUS There is no flagellum. (Egg:- Lactobaeiltes ) MONOTRICHOUS Single pdar flagellum can rotate both clock and anti-clockwise Resulting in forwarding movement and backward movement respectively (Egg:-vibrio chderae ) AMPHITRICHOUS One flagellum is present on each end. Movement are like monotrichous flagella. (Egg:- Alkaligens fuecalis )

7. LOPHOTRICHOUS Tufte of flagella present at one or both sides. Propagates clockwise and anticlockwise (Egg:- spirulina) PERITRICHOUS Numerous flagella are present all over the bacterial body Anticlockwise rotation produces one directional movement. (Egg:-salmonella typhi.)

8. CEPHALO TRICHOUS Several flagella are present at both sides. Movement are similar to monoicous flagella (Egg:-pesto monas)

9. STRUCTURE Flagella composed of 3 parts. FILOMENT HOOK BASAL BODY

10. FILOMENT Longest portion of the flagellum. Extends from the cell surface to the tip. 13-17 nm in diameter Hollow, rigid, cylinder Composed of parallels sub fibrils of 30-40 ic da Subunits of a single protein called flagellum. Ends with a capping protein Forms a left handed helix as it exists the cell.

11. HOOK Short, carved, flexible segment. Acts as a “sleeve” from which flagella filament emerges. Links filament to Basel body. It is quick different from filament. Slightly useds that the filament. Hook is made up of different protein subunits.

12. BASEL BODY Most complex part of flagella. Protein of flangeless embedded in the cell Made of 2 rings connected to a central red In gram negative Bactria. 4rings (4PS,M) 10 proteins comprise the outer rings Flagella's antigens-”H antigen”

13. Demonstration of flagella Direct demonstration of flagella Tannic acid staining( Leifson's method & Ryu's method) Electron microscopy Indirect means by demonstrating the motility Cragie tube method Hanging drop method Semisolid medium Dark ground/Phase contrast microscopy

14. Ryu's method Mordant solution 0 ml 5% Phenol 2g Tannic Acid 10 ml saturated aqueous solution of Aluminium potassium sulphate Ryu's stain 10 ml Crystal Violet, saturated ethanolic solution (12g/100ml of 95% ethanol) 100 ml Mordant solution

15. Method Place 2 drops of bacteria] suspension towards 1 end of acid cleaned microscope slide & air dry Draw a perpendicular line on the glass surface with a wax pencil towards opposite end from dried suspension Place the slide on a a tilted rack Overlay with thin film of stain After 5-15 n1ins, as alcohol evaporates, precipitate forms Rinse the slide with running water & air dry Flagella stains red to blue black

16. Grow bacteria for 16-24 hours on a a non inhibitory medium Touch a a loopful of water onto the edge of a colony & let motile bacteria swim into it Transfer this into a loopful of water on a slide to get a turbid suspension Cover with coverslip After 5-10 mins, add 2 drops of Ryu's stain to the edge of coverslip Leave for 5-15 mins at ambient temperature Examine under oil immersion Flagella stains violet

17. Leif son's method Leif son's stain 1.2% Basic fuchsin 95% alcohol 3% Tannic acid in water 1.5% NaCl in water Final stain - Combine 3 stock solutions in equal volumes - Use immediately after preparation - Store in tightly stoppered bottle - Precipitate formed during storage should not be disturbed Remove staining solution from the top with a pipette

18. Hanging Drop Preparation Use a hollow ground slide (cavity slide) Encircle the concavity with a line streak of soft petroleum jelly applied with a glass rod to the surface of the slide just outside the concavity Draw a V shaped line on the surface of coverslip Place the suspension on the same side of the coverslip within the angle of the "V” Invert the slide over the coverslip, then quickly tum around the slide so that the coverslip is uppermost The drop will be hanging from the coverslip in the centre of the concavity

19. Detection of motility using semi solid agar 0.4% Japanese agar/0.2% New Zealand agar dissolved in nutrient broth or peptone water Final medium - Clear & transparent Pour 10 ml amounts m test tubes & leave to set noculate with a straight wire ,making a single stab down the centre of the tube to half the depth of the medium Incubate under conditions favouring motility