Bacterial anatomy

Study slides for nursing class

1. BACTERIAL ANATOMY Dr. Sumesh Kumar Dash Department of Microbiology IMS & SUM Hospital

2. CLASSIFICATION Microorganism are grouped under 2 Prokaryotes (Bacteria & Blue-green algae) Eukaryotes (Fungi, Parasites, other algae) Viruses are neither prokaryotes nor eukaryotes as they lack the characteristics of living thinks except replication.

3. SIZE Bacteria size in micrometer and virus size in nanometer Bacteria observed by light microscope and Viruses observed by electron microscope To see microorganisms – staining is used

4. MORPHOLOGY OF BACTERIA Depending on their shape; Cocci - oval/spherical cells Bacilli- rod shaped Arrangement; Singles Pairs Chains clusters Based on gram staining property; Gram positive Gram negative

5. BACTERIAL CELL Outer layer/Envelope- cellwall cytoplasmic/plasma membrane Cytoplasm- mesosomes ribosomes vacuoles nucleoid Appendages- capsule flagella fimbriae/pili

6. CELL WALL Chemically composed of peptidoglycan

7. GRAM POSITIVE CELL WALL Peptidoglycan layer 50-100 layers thick 16-80nm Teichoic acids 2 types: Cell wall teichoic acid Lipoteichoic acid

8. GRAM NEGATIVE CELL WALL Peptidoglycan layer 1-2 layer thick 2-3nm Outer membrane Porin proteins Lipopolysaccharide (LPS) Lipid A Core polysaccharide O side chain /O antigen

9. DIFFERENCE BETWEEN GRAM POSITIVE & GRAM NEGATIVE CELL WALL Characters GRAM + GRAM - peptidoglycan layer Thick Thin Aromatic and sulphur containing amino acids Absent Present Teichoic acids Present Absent Gram stain Violet Red

10. FUNCTIONS OF CELL WALL Maintaining the cells characteristic shape Providing a rigid platform for surface appendages- flagella , fimbriae / pili all emanate from the wall and extend beyond it. Providing attachment sites for bacteriophage Be the sites of major antigenic determinant of cell surface- endotoxcity Site of action of many antibiotics & resistance

11. CYTOPLASMIC/CELL MEMBRANE 5-10nm thick Phospholipid bilayer With integral and peripheral proteins Selective permeability i:e - semipermeable Site of ATP production Viability

12. CYTOPLASM Viscous watery solution containing organic & inorganic solutes, biosynthetic components which required for the growth & cell division, together with genetic material. Contains RIBOSOMES, MESOSOMES INTRACYTOPLASMIC INCLUSION BODIES VACUOLES NUCLEOUS

13. RIBOSOMES Sites for protein synthesis. 10-20 nm in size.

14. MESOSOMES / Chondroids Vesicular/convoluted/ multilaminated More prominent in G+. LOCATION: Often found next to septa, in dividing bacteria or seen attached to nuclear body. FUNCTION: Site of bacterial respiration

15. INTRACYTOPLASMIC INCLUSIONS Storage sites for nutrients/energy. Formed under nutritional deficiency conditions & disappear in the presence of excess nutrients Staining Toluidine blue, Neisser, Albert, Acid-fast, wet films Electron microscopy

16. VACUOLES Vacuoles are fluid containing cavities Separated from cytoplasm by a membrane Function - uncertain

17. NUCLEOID Genetic material arranged in irregular shape Oval, Elongated Have no nuclear membrane Seen by Electron Microscope Plasmid Extrachromosomal ds circular DNA. Not essential for life. Present singly or in multiple numbers. Episomes - when integrated with chromosomal DNA. Drug resistance and toxigenicity

18. THANK YOU