BIOLOGIC REQUIREMENTS OF THE BACTERIAL CELL

• I. ATMOSPHERIC REQUIREMENTS---USEFUL IN IDENTIFYING BACTERIA:

• A. RELATIONSHIP TO OXYGEN:• 1. OBLIGATE AEROBES---REQUIRE OXYGEN

CONCENTRATIONS COMPARABLE TO THAT FOUND IN ROOM AIR (20-21% O2)– * Mycobacteria– * certain fungi

• 2. MICROAEROPHILES---REQUIRE OXYGEN CONCENTRATION LOWER THAN THAT AT ROOM TEMP. FOR MULTIPLICATION( 5% O2)– * Neiserria gonorrheae– * Campylobacter

3. ANAEROBES---DO NOT REQUIRE OXYGEN FOR LIFE AND REPRODUCTION; MAY VARY IN THEIR SENSITIVITY TO OXYGEN

– A. OBLIGATE ANAEROBE---CAN GROW IN AN ENVIRONMENT CONTAINING NO OXYGEN

– B. AEROTOLERANT ANAEROBE---DOES NOT REQUIRE OXYGEN, GROWS BETTER IN THE ABSENCE OF OXYGEN BUT CAN SURVIVE IN ATMOSPHERES CONTAINING MOLECULAR OXYGEN (AIR/ CO2 INCUBATOR)

– C. FACULTATIVE ANAEROBES---CAPABLE OF SURVIVING IN EITHER THE PRESENCE OR ABSENCE OF OXYGEN (0 % O2 TO 20 TO 21% O2)

– ***MEMBERS OF ENTEROBACTERIACEAE/ STREPTOCOCCI/ STAPHYLOCOCCI

– D. CAPNOPHILES---GROW BETTER IN THE PRESENCE OF INCREASED CONCENTRATIONS OF CO2

– EX. ANAEROBES---BACTEROIDES/FUSOBACTERIUM– AEROBES----NEISSERIA/CAMPYLOBACTER/

HAEMOPHILUS

• II. NUTRITIONAL REQUIREMENTS• * PROTEINS---COMPRISES 50% OF THE BACTERIAL

CELL• ***CARBON/HYDROGEN/OXYGEN/SULFUR/

PHOSPHORUS/NITROGEN• ***POTASSIUM/CALCIUM/IRON/MANGANESE/

MAGNESIUM/COBALT/COPPER/ZINC/URANIUM ( SPECIAL ELEMENTS REQUIRED BY BACTERIA)

• ***FASTIDIOUS----ORGANISMS WITH SPECIALLY DEMANDING NUTRITIONAL REQUIREMENTS

• * GROWTH FACTORS• * SOURCES OF ENERGY• ***ALL BACTERIA DERIVE THEIR CARBON AND

NITROGEN FROM ORGANIC MATTER, EXCEPT THE SAPROPHYTES

• KINDS OF ORGANISMS ACCDG. TO WHERE NOURISHMENT IS OBTAINED:

• 1. SAPROPHYTES---FROM NON-LIVING ORGANIC MATTER

• *** PARASITES---DEPEND ON LIVING MATTER FOR SUSTENANCE

• *** FACULTATIVE SAPROPHYTES---USUALLY OBTAIN NOURISHMENT FROM LIVING MATTER BUT MAY OBTAIN IT FROM THE DEAD ORGANIC MATTER.

• ***FACULTATIVE PARASITES---USUALLY OBTAIN THEIR NOURISHMENT FROM DEAD ORGANIC MATTER BUT MAY OBTAIN IT FROM LIVING MATTER.

• ***HETEROTROPHS/ ORGANOTROPHS--- OBTAIN THEIR NUTRIENTS BY BREAKING DOWN ORGANIC MATTER INTO SIMPLER INORGANIC SUBSTANCES.

• MOISTURE___75-80 % OF BACTERIAL CELL IS WATER; NEEDED TO DISSOLVE FOOD MATERIALS IN THE ENVIRONMENT

• DRYING---DETRIMENTAL TO BACTERIA GROWTH

• TEMPERATURE: • *** OPTIMUM TEMP----BEST TEMP FOR

GROWTH• *** MINIMUM TEMP.---LOWEST TEMP. AT

WHICH SPORES WILL GROW.• ***MAXIMUM TEMP. HIGHEST TEMP AT

WHICH GROWTH IS POSSIBLE.

• *** 42-45 DEGREES CELCIUS IS THE HIGHEST TEMP WHERE BACTERIA CAN STILL MULTIPLY; 20 DEGREES CELCIUS---LOWEST TEMP AT WHICH THEY CAN MULTIPLY

• ***THERMOPHILES---HEAT-LOVING SPECIES; CAN GROW ABOVE 45 DEGREES CELCIUS TEMP.

• PSYCHROPHILES/CRYOPHILES---COLD-LOVING SPECIES;CAN GROW AT TEMP JUST ABOVE THE FREEZING POINT

• ***COLD RETARDS OR STOPS BACTERIAL GROWTH THUS EMPLOYED IN THE PROCESS OF REFRIGERATION IN ORDER TO PROLONG THE SPOILAGE OF FOOD

Ph---refers to the acidity/alkalinity of the medium

• ***PREFERRED PH IS BETWEEN 6-8• **BEST PH FOR PATHOGENS IS PH 7

(NEUTRAL)

• OXYGEN REQUIREMENT:• ***AEROBES--- GROW IN THE PRESENCE OF

FREE ATMOSPHERIC OXYGEN

• OBLIGATE AEROBES---CANNOT DEVELOP IN THE ABSENCE OF FREE OXYGEN

• * ANAEROBES---OBTAAIN THEIR OXYGEN FROM OXYGEN CONTAINING COMPOUNDS LIKE INORGANIC SULFATES, NITRATES, CARBONATES OR FROM ORGANIC COMPOUNDS

• * OBLIGATE ANAEROBES---ORGNISMS WHOSE ENZYME SYSTEMS ARE INACTIVATED BY ATMOSPHERIC OXYGEN

• * FACULTATIVE ORGANISMS---ADAPTABLE EITHER TO THE PRESENCE OR ABSENCE OF ATMOSPHERIC OXYGEN

• * MICROAEROPHILES---ORGANISMS THAT CAN GROW EVEN IIN LOWERED OXYGEN CONTENT IN THE AIR

• * CAPNOPHILES---NEED 3-10 % INCREASE IN CARBON DIOXIDE CONTENT IN THE AIR TO INITIATE DEVELOPMENT

LIGHT REQUIREMENTS:

• RED/ YELLOW----LITTLE BACTERICIDAL EFFECT• *GREEN---HAVE LESS KILLING ACTION• *VIOLE/ULTRAVIOLET/ BLUE---LIGHT

WAVELENGTHS THAT ARE HIGHLY DESTRUCTIVE TO THE BACTERIAL CELL

• ** SOME SAPROPHYTIC SPECIES USE LIGHT FOR AUTOTROPHIC ACTIVITY

BY-PRODUCTS OF BACTERIAL GROWTH

• BACTERIAL METABOLISM---DEPLETES FOOD SUPPLY & RELEASE PRODUCTS THAT INHIBIT FURTHER BACTERIAL GROWTH

• EX. PRODUCTION OF ORGANIC ACIDS & OTHER PRODUCTS

• ***ELECTRICITY & RADIANT ENERGY---INHIBIT BACTERIAL GROWTH

• **CHEMICALS---DESTROY & INHIBIT THE GROWTH OF BACTERIA

• CHEMOTAXIS---RESPONSES TO CHEMICALS; POSITIVE OR NEGATIVE RESPONSES

• **OSMOTIC PRESSURE----MOST BACTERIA RESIST SMALL CHANGES IN OSMOTIOC PRESSURE

• ** BACTERIA CAN BE KILLED BY HIGH CONCENTRATIONS OF SALT OR SUGAR THUS EMPLOYED IN FOOD PRESERVATION

• ***OSMOPHILES----PREFER HIGH SALT CONCENTRATIONS; CLASSIFIED AS HALOPHILES OR SALT LOVERS WHERE THEY CAN TOLERATE HIGH CONCETRATIONS OF SALT

BACTERIAL INTER- RELATIONS

• SYMBIOSIS---BACTERIA GROWING WELL TOGETHER; BOTH PARTIES ARE BENEFITTED

• 1. SYNGERGISTIC RELATIONSHIP BETWEEN STAPHYLOCOCCI & THE INFLUENZA BACILLI

• 2. LEGUMES & THE NITROGEN-FIXING BACTERIA---NITROSOMONAS/ NITROBACTER

• ***ANTAGONISM---PRESENCE OF 1 ORGNAISM INHIBITS THE OTHER DUE TO SUBSTANCES THAT ARE SECRETED

MAJOR METABOLIC ACTIVITIES

• ENZYMES----PLAY AN IMPT ROLE IN THE METABOLLIC ACTIVITIES OF BACTERIA

• 2,000-3,000 ENZYMES IN THE BACTERIAL CELL UNDER THE CONTROL OF THE DNA APPARATUS

• CHEMOSYNTHESIS---PROCESSING OF ENERGY FROM THE CHEMICAL ALTERATION OF SUBSTANCES AT HAND

• 1. BACTERIAL DIGESTION---MAKES USE OF HYDROLASES (ENZYMES) & HYDROLYSIS---PROCESS INVOLVING THE ADDITION OF WATER

• 2. ABSORPTION---VIA DIFFUSION & ACTIVE TRANSPORT OF MOLECULES

• 3. OXIDATION---PREPARATION OF MOLECULES FOR A POSSIBLE BONDING OR CHEMICAL COMBINATION

• ---STARTS WITH PHOSPHORYLATION • INVOLVES

OXIDASES/DEHYDROGENASES/COENZYMES OF THE CYTOCHROME SYSTEM

• INVOLVES TRANSFER OF ELECTRONS RESULTING IN AN OXIDIZED OR REDUCED PRODUCT WHERE ENERGY IS LIBERATED OR TRAPPED

CLASSES OF BIOLOGIC OXIDATION:

• A. AEROBIC---ULTIMATE HYDROGEN ACCEPTOR IS MOLECULAR OXYGEN

• B. ANAEROBIC---HYDROGEN ACCEPTOR IS INORGANIOC NITRATE, SULFATE OR CARBONATE

• FERMENTATION---HYDROGEN ACCEPTOR IS AN ORGANIC COMPOUND; USES ORGNANIC COMPOUNDS BOTH AS DONORS & ELECTRON ACCEPTORS

MEDICALLY RELATED ACTIVITIES:

• ***TOXIGENICITY---TOXIN PRODUCTION• ***TOXICITY---POTENCY OF THE TOXINS• A. EXOTOXINS---PROTEINS IN NATURE• ------ANTIGENIC; PRODUCES ANTITOXIN• -----SPECIFIC---CAUSES 1 DISEASE & NOTHING

ELSE• ANATOXINS/ TOXOIDS---MODIFIED TOXINS THAT

CAN NO LONGER CAUSE DISEASE BUT CAN STILL PRODUCE IMMUNITY TO THE DISEASE

• B. ENDOTOXINS---MADE UP OF COMPLEX LIPOPOLYSACCHARIDES

• ---DO NOT PROMOTE ANTITOXIN FORMATION• ---NON-SPECIFIC• ---CANNOT BE CONVERTED INTO TOXOIDS• EX. SALMONELLA TYPHI• NEISSERIA MENINGITIDES

HARMFUL METABOLLIC PRODUCTS

• ---MAY NOT BE DIRECTLY TOXIC BUT RELATED SIGNIFICANTLY TO DISEASE

• 1. HEMOLYSINS---CAUSE LYSIS OF THE RED BLOOD CELLS

• 2 TYPES OF BACTERIAL HEMOLYSINS:• A. FILTRABLE• B. THOSE THAT ARE DEMONSTRATED ABOUT

THE BACTERIAL COLONY ON A CULTURE MEDIUM CONTAINING RBCs

• & HEMOLYSINS ---- NAMED AFTER THE BACTERIA THAT GIVES RISE TO THEM

• EX. STAPHYLOLYSIN• STREPTOLYSINS• 2. LEUKOCIDINS---DESTROY

POLYMORPHONUCLEAR NEUTROPHILIC LEUKOCYTES

• ***FORMED BY PNEUMOCOCCI,STREPTOCOCCI & STAPHYLOCOCCI

• 3. COAGULASE---ACCELERATE COAGULATION OF BLOOD

• EX. STAPHYLOCOCCI• COAGULASE TEST---USED TO DIFFERENTIATE

PATHOGENIC FROM NON-PATHOGENIC BACTERIA• 4. BACTERIAL KINASES---ACT ON CERTAIN

COMPONENTS OF THE BLOOD TO LIQUIFY FIBRIN; INTERFERE WITH BLOOD COAGULATION

• EX. STREPTOKINASE/FIBRINOLYSIS---PRODUCED BY MANY HENOLYTIC STREPTOCOCCI, STAPHYLOCOCCI & OTHER BACTERIA

• ---USED TO DISSOLVE BLOOD CLOTS & TO PREVENT THE FORMATION OF ADHESIONS THAT WOULD BE LAID DOWN ON THE FIBRIN PRECIPITATED IN THE BODY CAVITIES

• -5. HYALURONIDASE---MAKE TISSUES MORE • PERMEABLE TO THE BACTERIA ELABORATING

IT• EX. PNEUMOCOCCI & STREPTOCOCCI• 6. BACTERIOCINS---BACTERIAL PROTEIN OR

POLYPEPTIDE SUSBTANCES PRODUCED BY STRAINS OF A FAMILY OF MICROBES

• 7. COLICINS----PRODUCED BY THE FAMILY ENTEROBACTERIACEAE; WILL ACT ON THE BACTERIAL MEMBRANE

• OTHER EFFECTS:• 1. PIGMENT PRODUCTION---IMPT. IN THE

IDENTIFICATION OF ORGANISMS BUT NOT RELATED TO DISEASE PRODUCTION

• ***PRODUCED BY BOTH PARASITIC & SAPROPHYTIC BACTERIA

• EX. STAPHYLOCOCCUS AUREUS---GOLD COLOR• PSEUDOMONAS AERUGINOSA---PRODUCES

THE BLUE-GREEN PIGMENT• HALOBACTERIUM HALOBIUM---PRODUCES

RED PIGMENT• SERRATIA MARCESCENS---RED PIGMENT

• 2. HEAT PRODUCTION----RESULTS IN THE HEATING OF DAMP HAY

• 3. LIGHT PRODUCTION• EX. BIOLUMINESCENCE---EXHIBITED BY

BACTERIA THAT LIVE IN SALT WATER; EMITS LIGHT AS THEY OPEN THEIR MOUTHS; LIGHT PRODUCERS ARE GENERALLY NON-PATHOGENIC

• 4. PRODUCTION OF ODORS---DUE TO DECOMPOSITION OF THE MATERIAL WHERE THE BACTERIA IS GROWING