THE MICROBIAL WORLD: MONERA: BACTERIA & ARCHAEOBACTERIA

PROTISTA: UNICELLULAR OR COLONIAL EUCARYOTES THAT LACK TRUE TISSUE.

FUNGI: EUKARYOTIC ORGANISMS WITH ABSORPTIVE NUTRITION & OFTEN MULTI-CELLULAR.

ANIMALIA & PLANTAE ARE NOT STUDIED BY THE MICROBIOLOGIST.

VIRUSES: ACELLULAR/ NON-LIVING

SIZE, SHAPE & ARRANGEMENT OF PROCARYOTIC CELLBACTERIA VARY IN THEIR SIZE FROM: MYCOPLASMA (LACK CELL WALLS AND ARE THE SMALLEST ORGANISMS CAPABLE OF INDEPENDENT REPRODUCTION) TO THOSE APPROX. THE SIZE OF THE LARGEST VIRUS (POX VIRUS).

SIZE, SHAPE & ARRANGEMENT OF PROCARYOTIC CELLSBACTERIA (PROCARYOTES) COME IN A VARIETY OF SHAPE:

SPHERES (COCCI), RODS (BACILLI), CURVED RODS (VIBRIOS), RIGID HELICES (SPIRILLA), FLEXIBLE HELICES (SPIROCHETES), LACKING A SPECIFIC CHARACTERISTIC FORM VARIABLE SHAPE (PLEOMORPHIC, E.G., CORYNEBACTERIUM).

Bacillusanthrax

Bacillus w/sporeTetanus bacillus

Club-shaped bacillusdiphtheria

Streptobacillus

DiplococcusS. pneumoniae

Diplococcusgonorrhea

StreptococcusSarcinae/packet of 8Cube-like

staphylococcusVibrio, e.g., cholera

Spirilla, Rigid + flagella

SpirochetedRigid/ no flagella

SIZE, SHAPE & ARRANGEMENT OF PROCARYOTIC CELLARRANGEMENT:BY REMAINING ATTACHED AFTER REPRODUCTION BACTERIA MAY HAVE CHARACTERISTIC ARRANGEMENTS: CHAINS (E.G., STREPTOCOCCUS); CLUSTERS (E.G., STAPHYLOCOCCUS); SQUARE PLANAR CONFIGURATION (TETRADS); CUBIC, PACKAGES OF EIGHT CELLS, CONFIGURATION (SARCINAE).

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

PROCARYOTIC CELL ORGANIZATION & STRUCTURETO OBSERVE BACTERIA, THEY MUST BE STAINED

STAINING & FIXATION PRESERVE FINE STRUCTURE OF ORGANISMS.

FIXATIES INCLUDE HEAT OR CHEMICALS (ETHANOL, GLUTERALDEHYDE, MERCURIC ACIDS)

FIXATIVES BIND TO MACROMOLECULES TO RENDER THEM INSOLUBLE, INACTIVE & IMMOBILE.

STAINSACIDIC: HAVE IONIZING GROUPS (COOH) NEGATIVE CHARGES; BIND TO POSITIVELY CHARGED CELL STRUCTURES.

BASIC: HAVE POSITIVE CHARGES; BIND TO NEGATIVELY CHARGED GROUPS ON CELL STRUCTURES.

PROCARYOTIC CELL ORGANIZATION & STRUCTUREOBSERVATION OF BACTERIA REQUIRE SEVERAL STAINING TECHNIQUES :

SIMPLE STAINING TECHNIQUESSINGLE DYE TO ENHANCE THE CONTRAST OF THE SPECIMEN AGAINST THE BACKGROUND.

DIFFERENTIAL STAINING DIVIDES BACTERIA INTO DIFFERENT GROUPS BASED ON STAINING PROPERTIES, e.g.,

GRAM STAININGACID FAST STAINING

SPECIAL STAINING TECHNIQUESSTAINING FOR SPECIFIC STRUCTURES. STAINS HAVE AFFINITY FOR CELL STRUCTURESTHEY HIGHLIGHT STRUCTURES AS STAINED COMPONENTS (POSITIVE STAINS)

ENDOSPORE STAININGGRANULE STAINING

VS.NEGATIVE STAINING - CELLS ARE LIGHT AGAINST A DARK BACK- GROUND (E.G., STAIN WITH INDIA INK) - CAPSULE STAINING FLAGELLA STAINING

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

NEGATIVE STAINING TO OBSERVE CAPSULE

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

THE CYTOPLASMIC MEMBRANE IS MADE UP OF AMPHIPATHIC LIPIDS IN A BILAYER AND IS SIMILAR TO THAT OF THE EUCARYOTIC CELL. IT IS:

A SELECTIVELY PERMEABLE MEMBRANE

LOCATION OF METABOLIC ENZYMES & TRANSPORT PROTEINS

SITE OF RESPIRATION

LIPID SYNTHESIS AND PHOTOSYNTHESIS

PROTEINS THAT ALLOW CELLS TO DETECT AND RESPOND TO CHEMICALS RESIDE IN THE MEMBRANE

PROCARYOTIC CELL ORGANIZATION & STRUCTURECELL ENVELOPE = OUTER COVERING OF PROCARYOTES & MADE UP OF PLASMA MEMBRANE + CELL WALL + OUTER MEMBRANES (GRAM NEGATIVES)

PLASMA MEMBRANE - SELECTIVELY PERMEABLE BARRIER- PROVIDES STRUCTURAL INTEGRITY TO BACTERIA LACKING CELL WALL (E.G., MYCOPLASMA)- SIMILAR IN COMPOSITION TO EUCARYOTIC MEMBRANE

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

AMPHIPATHIC MOL: HYDROPHILIC POLAR GROUP + HYDROPHOBIC NON-POLAR CHAIN

PROCARYOTIC CELL ORGANIZATION & STRUCTURECELL WALL MAINTAINS CELL SHAPE AND CONFORMATION - RIGID, COMPLEX INFLEXIBLE LYER EXTERNAL TO CELL MEMBRANE - ENABLES CELLS TO SURVIVE IN HYPOTONIC ENVIRONMENTS - CELLS LACKING CELL WALL (MYCOPLASMA) COMPENSATE WITH STEROL CONTAINING PLASMA MEMBRANES - CELL WALLS ARE NOT UNIQUE TO BACTERIA (PLANTS = CELLULOSE; FUNGi=CHITIN). BACTERI CELL WALL MADE UP OF POLYSACCHARIDE CALLED PEPTIDOGLYCAN OR MUREIN - ONE TO SEVERAL LAYERS THICK - MADE UP OF REPEATING UNITS OF TWO CARBOHYDRATE DERIVATIVES:

N-ACETYLGLUCOSAMINE (NAG)N-ACETYLMURAMIC ACID (NAM) - FOUND NOWHER ELSE IN NATURE

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

FOUR AMINO ACIDS MAKE UP WHAT IS CALLED A TETRAPEPTIDE, ATTACHED TO THE NAM.

MOST GRAM POSITIVES COCCI HAVE SIMILAR TETRAPEPTIDE EXCEPT DAP IS REPLACED BY L-LYSINE

TETRAPEPTIDE MAY BE FURTHER MODIFIED IN OTHER BACTERIA

B(1,4)

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

MAJOR STRENGTH OF CELL WALL COMES FROM PERIODIC CROSS LINKINGBETWEEN THE THIRD & FOURTH AA ON ADJACENT TETRAPEPTIDE

CROSS-LINKING MAY BE EITHER DIRECTLY (AS IN MOST GM NEGATIVE CELLS) OR VIA A PENTA-GLYCINE LINK (AS IN MANY GM POSITIVE CELLS)

PROCARYOTIC CELL ORGANIZATION & STRUCTURECROSS-LINKING MAY BE EITHER DIRECTLY (AS IN MOST GM NEGATIVE CELLS) OR VIA A PENTA-GLYCINE LINK (AS IN MANY GM POSITIVE CELLS)

NOT ALL PROKARYOTES HAVE PEPTIDO- GLYCAN IN THEIR CELL WALLS: ARCHAEA INSTEAD HAVE CELL WALLS COMPOSED OF POLYSACCHARIDES, GLYCOPROTEINS & PROTEINS. THEY DO NOT HAVE NAM IN THEIR WALLS; MYCOPLASMA, WITH NO CELL WALLS, HAVE CELL MEMBRANES WITH STEROLS TO PROVIDE STRENGTH

PROCARYOTIC CELL ORGANIZATION & STRUCTUREIN GM POSITIVES PEPTIDOGLYCAN MAY BE AS MUCH AS 40 LAYERS THICK

MOST OF THE CELL WALL (90%) MAY BE MADE UP OF PEPTIDOGLYCAN, BUT THE REMAINDER MAY BE OF ACIDIC POLYSACCHARIDE CALLED TEICHOIC ACID (THEY ARE NEGATIVELY CHARGED MOLECULES)

PROCARYOTIC CELL ORGANIZATION & STRUCTUREGM NEGATIVES HAVE THINNER CELL WALLS (A FEW LAYERS THICK AND APROX. 5- 20% OF ENVELOPE). INSTEAD THEY HAVE AN OUTER MEMBRANE STRUCTURE SIMILAR TO THE CELL MEMBRANE, BUT THE COMPOSITION IS SLIGHTLY DIFFERENT: LIPOPOLYSACCHARIDE (LPS) MAKE UP ABOUT 40% OF THE OUTER LIPID BI-LAYER.

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

O-SIDE CHAIN

CORE-POLYSACCHARIDE

LIPID A

O SIDE: CHAIN VARIES DEPENDING ON THE BACTERIUMCORE POLYSACCHARIDE: RELATIVELY CONSTANT COMPOSITIONLIPID A COMPOSED: OF GLYCOLIPIDS ASSOCIATED WITH TOXIC ACTIVITY IN GRAM-NEGATIVE BCTERIUM

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

CELL WALL OF THE ACID-FAST BACTERIA

THICK WALL LIKE THAT OF GM POSIIVES.

PEPTIDOGLYCAN IS LESS & ABOUT 60% LIPID.

THE LIPID MAKES THE BACTERIA IMPERMEABLE TO MOST STAINS AND PROTECTS IT FROM ACIDS AND ALKALIS

CARBOLFUCHSIN BINDS CYTOPLASM & RESIST ACID- ALCOHOL DESTAINING.

SLOW GROWTH OF BACTERIA DUE TO INEFFICIENT ENTRY OF NUTRIENTS INTO THE CELL; LARGE AMOUNTS OF ENERGY MUST BE EXPENDED TO TAKE UP NUTRIENTS.

MYCOBACTERIA

PROCARYOTIC CELL ORGANIZATION & STRUCTURETHE IMPORTANCE OF CELL ENVELOPES IN PRESERVING THE STRUCTURAL INTEGTITY OF BACTERIA IS ILLUSTRATED THROUGH THE LABORATORY CONSTRUCTS PROTOPLASTS & SPHEROPLAST (CELLS WITHOUT MUREIN).

PROTOPLAST= GRAM POSITIVE CELLS WITHOUT MUREINSPHEROPLAST= GRAMNEGATIVE CELLS WITHOUT MUREIN (RETAIN OUTER MEMBRANE)

LYSOZYME OR PENICILLIN USED TO CREATE THESE CELLS. THEY SURVIVE ONLY IN ISOTONIC SOLUTIONS

PROCARYOTIC CELL ORGANIZATION & STRUCTURETHE CELL WALL OF THE ARCHAEATHE PROCARYOTES SURVIVE IN EXTREME ENVIRONMENTS (HIGH SALT, TEMPERATURES, AND pH EXTREMES)

CONSIST OF BOTH GRAM POSITIVE AND GRAM NEGATIVE CELLS - THEY DO NOT HAVE MURAMIC ACID OR D-AMINO ACIDS. - SOME ARCHAE HAVE A MOLECULE CALLED PSEUDOPEPTIDOGLYCAN (REPEATING UNITS OF NAG AND N-ACETYLTALOSAMINURONIC ACID AND L-AMINO ACIDS (NOT THE D-AMINOACIDS FOUND IN TRADITIONAL PEPTIDOGLYCAN).

- OTHERS HAVE SURFACE MONOLAYER OF PROTEINS OR GLYCOPROTEINS & LACK PSEUDOMUREIN.

-OTHERS HAVE NO WALLS; CYTOPLASMIC MEMBRANE IS THE ONLY CONSTITUENT OF THE ENVELOPE

-BETWEEN THE ALTERNATING CARBOHYDRATES IS BETA(1,3) [NOT

BETA(1,4) OF PEPTIDOGLYCAN] AND IT IS RESISTAN TO LYSOZYME.

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

PERIPLASMIC SPACE: GAP BETWEEN PLASMA MEMBRANE AND THE CELL WALL.

MOST EASILY OBSERVED IN GM-NEGATIVES. LESS DEFINED IN GM- POSITIVES

ACTIVE AREA OF CELL METABOLISM WITH HYDROLYTIC ENZYMES, TRANSPORT PROTEINS; AND CELL WALL BUILDING BLOCKS.

NOTE DIFFERENCES IN THE SIZE OF THE PERIPLASMIC SPACE

PROCARYOTIC CELL ORGANIZATION & STRUCTUREGLYCOCALYX: REFERS TO ALL POLYSACCHARIDE-CONTAINING SUBSTANCES FOUND OUTSIDE THE CELL WALL (I.E., CAPSULE OR SLIME LAYER OR GLYCOCALYX)THE CAPSULE:EXTERNAL TO THE ENVELOPE & PRESENT IN SOME BACTERIA (NOT ALL MEMBERS OF A SPECIES MAY HAVE CAPSULES)

A LOOSE GEL, COMPOSED OF POLYSACCHARIDE, PROTEIN, OR ONLY GLYCOPROTEINS

PROTECTS CELL FROM DESSICATION, NUTRIENT LOSS AND PHAGOCYTOSIS

MAY BE VISUALIZED BY QUELLUNG RXN (SPECIFIC ANTIBODIES BIND TO CAPSULE & INCREASE REFRACTIVITY & CAPSULE APPEARS SWOLEN) SLIME LAYER (GLYCOCALYX):THINNER THAN CAPSULE, AND WHEN PRESENT PREVENTS CELLS FROM DRYING OUT & TRAPS NUTRIENT.

POLYSACCHARIDE ARRANGESD AS FIBROUS MATRIX

ALSO ALLOWS BACTERIA TO ADHERE TO EACH OTHER AND OTHER OBJECTS (EG., BACTERIA IN DENTAL PLAQUE ON TOOTH SURFACE)

PROCARYOTIC CELL ORGANIZATION & STRUCTURE

PROCARYOTIC CELL ORGANIZATION & STRUCTUREOTHER EXTERNAL STRUCTURES:FLAGELLA

RESPONSIBLE FOR MOTILITYUSED IN CHEMOTAXIS (MOVEMENT TO OR AWAY FROM SUBSTANCESIN THEIR ENVIRONMENT) OR PHOTOTAXISMAY BE ARRANGED DIFFERENTLY DEPENDING ON SPECIES

SINGLE FLAGELLUM = MONOTRICHOUS

ONE FLAGELLUM AT EACH POLE = AMPHITRICHOUS

TWO OR MORE FLAGELLA AT ONE OR BOTH POLES = LOPHOTRICHOUS

FLAGELLA ALL OVER THE SURFACE = PERITRICHOUS

MONOTRICHOUS

AMPHITRICHOUS

LOPHOTRICHOUS PERITRICHOUS

PROCARYOTIC CELL ORGANIZATION & STRUCTUREFIMBRIA & PILI (SOMETIMES USED INTERCHANGBLY)

FIMBRIA- SHORTER AND STRAIGHTER THAN FLAGELLUM- FIMRAE MAY BE EVENLY DISTRIBUTED OVER ENTIRE SURFACE USED FOR ATTACHMENT (EG., NEISSERIA GONORRHOEA USE THEM TO ATTACH TO MUCOU MEMBRANES AND CAUSE DISEASE)

PILI- USUALLY LONGER THAN FIMBRIAE; NUMBER ONLY 1 OR 2/CELL - USUALLY USED IN DNA TRANSFER DURING CONJUGATION