R.KAVITHA, M.PHARM, LECTURER, DEPARTMENT OF PHARMACEUTICS, SRM … · LECTURER, DEPARTMENT OF...
-
Upload
truongkien -
Category
Documents
-
view
274 -
download
2
Transcript of R.KAVITHA, M.PHARM, LECTURER, DEPARTMENT OF PHARMACEUTICS, SRM … · LECTURER, DEPARTMENT OF...
R.KAVITHA, M.PHARM,LECTURER, DEPARTMENT OF PHARMACEUTICS,
SRM COLLEGE OF PHARMACY,SRM UNIVERSITY, KATTANKULATHUR.
Size of BacteriaAverage bacteria 0.5 ‐ 2.0 um in diam.
RBC is 7.5 um in diam.Surface Area ~12 um^2Volume is ~4 umSurface Area to Volume is 3:1Typical Eukaryote Cell SA/Vol is 0.3:1Food enters through SA, quickly reaches all parts of bacteriaEukaroytes need structures & organelles
Shapes of BacteriaCoccus
Chain = StreptoccusCluster = Staphylococcus
BacillusChain = Streptobacillus
CoccobacillusVibrio = curvedSpirillumSpirocheteSquareStar
Bacterial StructuresFlagella PiliCapsulePlasma MembraneCytoplasmCell WallLipopolysaccharidesTeichoic AcidsInclusionsSpores
FlagellaMotility ‐movementSwarming occurs with some bacteria
Spread across Petri DishProteus species most evident
Arrangement basis for classificationMonotrichous; 1 flagellaLophotrichous; tuft at one endAmphitrichous; both endsPeritrichous; all around bacteria
Observe Picture in Micro Lab.
Mono- or Lophotrichorus
PiliShort protein appendages
smaller than flagellaAdhere bacteria to surfaces
E. coli has numerous typesK88, K99, F41, etc.
Antibodies to will block adheranceF‐pilus; used in conjugation
Exchange of genetic informationFlotation; increase boyancy
Pellicle (scum on water)More oxygen on surface
F‐Pilus for Conjugation
Capsule or Slime LayerGlycocalyx ‐ Polysaccharide on external surfaceAdhere bacteria to surface
S. mutans and enamel of teethPrevents Phagocytosis
Complement can’t penetrate sugars
Cytoplasm80% Water {20% Salts‐Proteins)
Osmotic Shock importantDNA is circular, Haploid
Advantages of 1N DNA over 2N DNAMore efficient; grows quickerMutations allow adaptation to environment quicker
Plasmids; extra circular DNAAntibiotic Resistance
No organelles (Mitochondria, Golgi, etc.)
Cell MembraneBilayer PhospholipidWater can penetrateFlexibleNot strong, ruptures easily
Osmotic Pressure created by cytoplasm
Cell Wall Peptido‐glycan Polymer (amino acids + sugars)Unique to bacteriaSugars; NAG & NAM
N‐acetylglucosamineN‐acetymuramic acid
D form of Amino acids used not L formHard to break down D form
Amino acids cross link NAG & NAM
Cell Wall SummaryDetermine shape of bacteriaStrength prevents osmotic rupture20‐40% of bacteriaUnique to bacteriaSome antibiotics effect directly
Penicillin
Video Clip on Cell Wall
Teichoic AcidsGram + onlyGlycerol, Phosphates, & RibitolAttachment for Phages
Lipopolysaccharide (LPS)Endotoxin or Pyrogen
Fever causingToxin nomenclature
Endo‐ part of bacteriaExo‐ excreted into environment
StructureLipid APolysaccharide
O Antigen of E. coli, Salmonella
G‐ bacteria onlyAlcohol/Acetone removes
LPS (cont’d)Functions
Toxic; kills mice, pigs, humansG‐ septicemia; death due to LPS
Pyrogen; causes feverDPT vaccination always causes fevers
Adjuvant; stimulates immunityHeat Resistant; hard to removeDetection (all topical & IV products)
Rabbits (measure fever)Horse shoe crab (Amoebocytes Lyse in presence of LPS)
LPS (cont’d.)Appearance of Colonies
Mucoid = Smooth (lots of LPS or capsule)Dry = Rough (little LPS or capsule)
O Antigen of Salmonella and E. coli2,000 different O Ags of Salmonella100’s different O Ags of E. coli
E. coli O157
O Ags differ in Sugars, not Lipid A
EndosporesResistant structure
Heat, irradiation, coldBoiling >1 hr still viable
Takes time and energy to make sporesLocation important in classification
Central, Subterminal, TerminalBacillus stearothermophilus ‐spores
Used for quality control of heat sterilization equipment
Bacillus anthracis ‐ spores Used in biological warfare
G+ vs. G‐G+
Thicker cell wallTeichoic Acids
G‐Endotoxin ‐ LPS
Which are more sensitive to Penicllin?Alcohol/Acetone affects which more?