BACTERIA
• UBIQUITOUS IN NATURE
• UNICELLULAR
• LIGHT MICROSCOPIC - 0.2 - 2
MICROMETERS IN DIAMETER; 2 - 8
MICROMETERS IN LENGTH
• PROCARYOTIC IN CELL STRUCTURE
• CELL SHAPE AND ARRANGEMENT
ANATOMY OF A TYPICAL
BACTERIUM
• THE GLYCOCALYX – A SUGAR COAT
• CAPSULE, SLIME LAYER, BIOFILM
– PRODUCED WITHIN THE CELL AND SECRETED
EXTRACELLULARLY
• CAPSULE
• CARBOHYDRATE - POLYSACCHARIDE
• WELL ORGANIZED
• LAYED DOWN EVENLY AROUND THE CELL WALL
• FIRMLY ATTACHED
• NOT EASILY PENETRATED
ADVANTAGES OF HAVING A CAPSULE
• ADHERENCE
• NUTRITION SOURCE
• PROTECTION
– ANTIBIOTICS
– IMMUNE SYSTEM
– NUTRIENT AND WATER LOSS
SLIME LAYER
• NOT WELL ORGANIZED
• EASILY PENETRATED
• ADVANTAGES OF A SLIME LAYER
BIOLFILM
• BACTERIA LIVE IN COMMUNITIES CALLED
BIOFILMS
• USUALLY ATTACHED TO SOMETHING –
CATHETER, HEART VALVE, TOOTH, MUCOUS
MEMBRANE
• ADVANTAGES OF A BIOFILM:
• PROTECTION FROM: DESSICATION, ANTIBIOTICS,
BODY’S IMMUNE SYSTEM
• 70% OF HUMAN BACTERIAL INFECTIONS
INVOLVE BIOLFILMS
THE BACTERIAL CELL WALL
• MAJOR COMPONENT OF MOST
BACTERIAL CELLS
• MAINTAINS THE SHAPE AND INTEGRITY
OF THE CELL
• PRESENT IN ALL PROCARYOTIC CELLS
EXCEPT THE MYCOPLASMAS
• MAJOR DIFFERENCES IN CELL WALLS
DEMONSTRATED BY THE GRAM STAIN
THE GRAM POSITIVE CELL
WALL
•
•
•
•
SINGLE LAYER
UP TO 90% PEPTIDOGLYCAN
15-20 nm THICK
CONTAIN TEICHOLIC ACIDS WHICH ARE
ACIDIC POLYSACCHARIDES
• CONTROL AUTOLYSINS IN THE CELL
THE GRAM NEGATIVE CELL
WALL
• SEVERAL LAYERS SEEN
• 10-15 nm THICK
• INTERESTING CHARACTERISTICS OF THE
AMINO ACIDS IN PEPTIDOGLYCAN
• AMINO ACIDS CAN TAKE ON TWO
STRUCTURAL CONFIRMATIONS IN SPACE
• D-AMINO ACIDS VS L-AMINO ACIDS
• DIAMINOPIMELIC ACID – AA FOUND ONLY
IN PEPTIDOGLYCAN
• INTERESTING CHEMICALS THAT EFFECT
THE CELL WALL OF BACTERIA.
• PENICILLIN
• LYSOZYME
• DIFFERENCES BETWEEN THE CELL WALLS
OF THE ARCHAEABACTERIA AND THE
EUBACTERIA.
• ARCHAEABACTERIA HAVE NO
PEPTIDOGLYCAN IN THEIR CELL WALLS
• THERE ARE NO D AMINO ACID ISOMERS IN
THE CELL WALL OF THE
ARCHAEABACTERIA. ONLY L AMINO ACID
ISOMERS
• THE ARCHAEABACTERIA ARE GRAM
VARIABLE
THE CELL MEMBRANE
• SIMILAR TO THAT OF EUCARYOTES
• 50% PROTEIN AND 50% LIPID IN CHEMICAL
COMPOSITION
• ACTIVE AND PASSIVE TRANSPORT
OBSERVED
• DIFFERENCES BETWEEN THE CELL
MEMBRANES OF THE EUCBATERIA AND
THE ARCHEOBACTERIA
– OVERLAPPING LIPID LAYERS
– DIFFERENT BONDING IN PHOSPHOLIPID
MOLECULES
CYTOPLASMIC CONTENTS
CYTOPLASMIC CONTENTS
• RIBOSOMES
– MAKE UP MAJOR PART OF CYTOPLASM
– 15,000+ PER CELL - POLYRIBOSOMES
– 60% PROTEIN AND 40% RNA
• STORAGE GRANULES
– CARBON RESERVE
• POLY-BETA-HYDROXYBUTYRATE
• GLYCOGEN
– VOLUTIN
– SULFUR
• ENDOSPORES
THE NUCLEAR APARATUS
• DNA
• USUALLY A SINGLE CIRCULAR MOLECULE
OF DOUBLE STRANDED DNA
• CAN BE LINEAR AS IN BORELLIA
BURGDORFERI
•
•
•
•
EXTRACHROMOSOMAL DNA – PLASMIDS
DEFINITION OF A PLASMID
REPLICATES AUTONOMOUSLY
EASILY PASSED FROM BACTERIUM TO
BACTERIUM
• PLASMID GENES ARE NOT NECESSARY
FOR THE SURVIVAL OF THE BACTERIUM
• PLASMIDS USED IN GENETIC
ENGINEERING
EXTERNAL STRUCTURES OF THE
BACTERIAL CELL
• FLAGELLA
– CHEMICAL COMPOSITION - PROTEIN
– ORGANELLE OF MOTILITY
– DIAMETER IS BELOW THE RESOLVING
POWER OF THE LIGHT MICROSCOPE
– ARRANGEMENT
• POLAR
• PERITRICHOUS
• FIMBRIAE - ADHESION
• PILUS - CONJUGATION
CLINICALLY SIGNIFICANT
BACTERIA
A VARIETY OF CLINICALLY SIGNIFICANT
BACTERIA AND THE DISEASES THEY CAUSE
• RODS - ARRANGEMENT
– ESCHERICHIA COLI – STRAIN 0157:H7
• HUS-hemolytic – uremic - syndrome
–
–
–
–
–
CLOSTRIDIUM
CORYNEBACTERIUM
MYCOBACTERIUM
LACTOBACILLUS
BACILLUS
• COCCI – ARRANGEMENT
• DIPLOCOCCI
• NEISSERIA GONORRHOEAE – pp 790-792
• NEISSERIA MENINGITIDIS – pp 645-646
• STREPTOCOCCI – pp 620-622;675-676; 714-715
• STREPTOCOCCUS PYOGENES
– SCARLET FEVER
– RHEUMATIC FEVER
• STREPTOCOCCUS PNEUMONIAE – pp 456;716
• ENTEROCOCCUS FAECIUM - VRE (VANCOMYCIN
RESISTANT ENTEROCOCCUS) – pp 593
– NOSOCOMIAL INFECTIONS
• TETRAD/SARCINAE - MICROCOCCUS LUTEUS
– STAPHYLOCOCCI
• STAPHYLOCOCCUS AUREUS – pp 436;593;61520;675;751-2; MRSA, VISA, VRSA
– NOSOCOMIAL INFECTIONS
• STAPHYLOCOCCUS EPIDERMIDIS
• STAPHYLOCOCCUS SAPROPHYTICUS
• SPIRALS
• VIBRIO – CURVED RODS – VIBRIO
CHOLORAE – pp 755-758
• SPIROCHETES
• TREPONEMA PALLIDUM – SYPHYLIS – pp
794-799
• BORRELIA BURGDORFERI – LYME DISEASE
• pp. 685-687
BACTERIAL DIVERSITY
• A VARIETY OF CLINICALLY SIGNIFICANT
ATYPICAL BACTERIA
• CHLAMYDIAE – PHYLUM- pp 336-7;636;727;729;792-4
• OBLIGATE INTRACELLULAR PARASITES
• NO PEPTIDOGLYCAN IN THEIR CELL WALL
• VERY SMALL RODS - 1.5 X 0.2 MICROMETERS
• ENERGY PARASITES
• TWO GENERA: CHLAMYDIA AND CHLAMYDOPHILA
• CHLAMYDIA TRACHOMATIS (STD)
• EYE DISEASE SEEN OFTEN IN THIRD
WORLD COUNTRIES
• CHLAMYDOPHILA PSITTACI – PSITTACOSIS
• CHLAMYDOPHILA PNEUMONIAE
• RICKETTSIAE – PHYLUM -pp 316;687-688
• OBLIGATE INTRACELLULAR PARASITES
• VERY SMALL PLEOMORPHIC RODS – 0.8 X
2.0 MICROMETERS
• TRANSMITTED FROM HOST TO HOST BY A
VECTOR – INSECTS AND TICKS
• MOST PATIENTS PRESENT WITH A RASH
• ROCKYMOUNTAIN SPOTTED FEVER
• MYCOPLASMAS – IN THE FAMILY
MYCOPLASMATACEAE – pp 333-4; 726,794
• NO CELL WALL
• FREE LIVING
• VERY SMALL – SMALLEST FREE LIVING
ORGANISMS KNOWN
• 0.3 – 0.5 MICROMETERS IN DIAMETER
• CAN SLIP THROUGH 0.2 MICROMETER
MEMBERANE FILTERS
• HAVE STEROLS IN THEIR CELL
MEMBRANES
• MYCOPLASMA PNEUMONIAE – WALKING
OR ATYPICAL PNEUMONIA
• MYCOPLASMA HOMINIS - STD