Structure of mycobacterium leprae

M leprae -its structure and bichemistry

1. STRUCTURE OF MYCOBACTERIUM LEPRAE

2. Discovered by Gerhard Armauer Hansen in 1873 , Norwegian physician . First bacterium- causing disease in humans.

3. Hansen - born in Bergen and got his degree in university of Oslo. W ith Daniel Cornelius Danielssen , he did the study of leprosy. In 1879 he gave tissue samples to Albert Neisser who stained the bacteria & announced his findings in 1880. Hansen as discoverer of the bacillus and Neisser as identifier of it as the etiological agent. Neisser put in some effort to downplay the assistance of Hansen. Hansen’s distinguished work was recognized at the International Leprosy Congress held at Bergen in 1909. Hansen had suffered from syphilis since the 1860s but died of heart disease

4. Cultured -Mouse foot pads of nine-banded armadillos .( Dasypus novemcinctus )

5. CHARACTERISTICS Family- Mycobacteriaceae . Schizomycete ; order- Actinomycetales Intracellular parasite – macrophages. Gross Morphology- straight / curved slender Capsulated Non-motile

6. Non sporing Acid fast Rod – 1 to 8u in length 0.2 to 0.5u in width Appear fragmented or beaded Cells stain homogeneously;(altered and dead) Divides by binary fission

7. Non cultivable; cultured only on footpad of Nine Banded Armadillos. Possesses enzyme phenol oxidase. Bound together like cigar bundles by lipid like substances – Glia. Only Mycobacterium – infecting peripheral nerves.

8. Resistence - 9 -16 days in warm humid climate. 46 days in moist soil. 2 hours in sunlight 30 minutes in UV rays

9. ULTRASTRUCTURE Components - Capsule Cell wall Cell membrane Cytoplasm

10. CAPSULE Electron transparent zone of foamy or vesicular material 2 capsular lipids- (a) phthicerol demycocerosate . (b)phenolic glycolipid-1 Protects bacteria- lysosomal enzymes & metabolites. Present in Urine and serum, helps in early diagnosis.

11. CELL WALL Outer and inner layer 20nm thick Consists of cross linked peptidoglycan attached to arabinogalactan polymer. Outer layer- Lipopolysaccharides & lipopolysaccharides- protein complexes Electron lucent

12. Inner layer- Peptidoglycan Electron dense Cell wall proteins form a major target of T cell immunogenicity. Mediates the uptake of nutrients into mycobacterium. Last structure to disappear with chemotheraphy .

13. CELL MEMBRANE Responsible for transport of molecules inside and out of the organism Composed of lipids & proteins LIPIDS- phospholipids PROTEINS- MMP-I & MMP II

14. CYTOPLASM Consist of storage granules, DNA, RNA. Concerned with translation and multiplication Gel electrophoresis separates these 3 major proteins

15. CLINICAL APPILICATION PCR technique for DNA amplification – high degree sensitivity PCR – sensitive method for detecting small number of M.leprae . Reverse transcriptase-PCR tecnique useful to detect live and dead bacteria

16. SUMMARY Mycobacteiaceae . Straight/ slightly curved slender, capsulated, non motile ,non sporing , acid fast. Binary fission. Cultured- footpad – nine banded armadillos. Glia. Infect peripheral nerves.

17. Capsule- electron transparent 2 capsular lipids- (PDIM & PGL -1) Cell wall- 2 layers. Cell membrane-responsible for molecules into and out membrane. Cytoplasm- Contains DNA, RNA, storage granules.

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