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BACTERIAL NUTRITIONAL GROUPS BASED ON ENERGY, REDUCTANT, CARBON SOURCES. CHEMICAL COMPOSITION OF A TYPICAL PROCARYOTIC CELL. CHEMICAL COMPOSITION OF A TYPICAL PROCARYOTIC CELL. OVERALL MACROMOLECULAR COMPOSITION OF AN AVERAGE E. COLI CELL. BACTERIAL NUTRITION. NUTRIENTS
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BACTERIAL NUTRITIONAL GROUPS BASED ON ENERGY, REDUCTANT, CARBON SOURCES
OVERALL MACROMOLECULAR COMPOSITION OF AN AVERAGE E. COLI CELL
BACTERIAL NUTRITION NUTRIENTS - COMPOUNDS WHICH BACTERIA REQUIRE FOR GROWTH MACRONUTRIENTS (10-2 – 10-3 M) - SOURCES OF MAJOR ELEMENTS COMPRISING BIOCHEMICAL COMPONENTS OF BACTERIAL CELLS - C , N , S , P , H , O
BACTERIAL NUTRITION (continued) MICRONUTRIENTS (10-4 – 10-6 M) - ELEMENTS (METAL CATIONS) REQUIRED FOR BIOCHEMICAL REACTIONS IN CELLS - USUALLY ENZYME CO-FACTORS - HIGH CONCENTRATION (ADDED TO MEDIA) K+, Mg+2, Ca+2, Fe+2 - LOW CONCENTRATION (TRACE ELEMENTS) Zn+2, Mn+2, Co+2, Ni+2, Mo+2 GROWTH FACTORS (10-3 – 10-5 M) - ANY BIOCHEMICAL COMPOUND AN ORGANISM REQUIRES FOR GROWTH BECAUSE THE ORGANISM IS UNABLE TO SYNTHESIZE IT. - AMINO ACIDS - PURINES AND PYRIMIDINES - VITAMINS (COENZYMES) - AUTOTROPH: ORGANISM UNABLE TO SYNTHESIZE REQUIRED BIOCHEMICAL COMPOUND; REQUIRES COMPOUND OF PRECURSOR AS GROWTH FACTOR
MACRONUTRIENTS • CARBON SOURCE - SUPPLY CARBON FOR BIOSYNTHESIS OF ALL CELL COMPONENTS TYPES - INORGANIC (CO2) – AUTOTROPHS - ORGANIC (ALL NATURALLY OCCURRING COMPOUNDS – HETEROTROPHS – ENERGY FROM OXIDATION OF ORGANIC COMPOUNDS - CARBON & ENERGY SOURCE - BACTERIA HAVE GREAT NUTRITIONAL DIVERSITY AND VERSATILITY FOR COMPOUND SERVING AS CARBON AND ENERGY SOURCES • NITROGEN SOURCE - SUPPLY NITROGEN FOR BIOSYNTHESIS OF AMINO ACIDS, NUCLEOTIDES, AMINO SUGARS AND COENZYMES TYPES - ORGANIC – AMINO ACIDS, PEPTIDES - INORGANIC – NH4+, NO3-, N2 1. NH4+ - ASSIMILATED DIRECTLY 2. NO3- - ASSIMILATORY NITRATE REDUCTION REDUCES NO3- TO NH4+ ONLY IN AMOUNTS REQUIRED FOR CELLULAR BIOSYNTHESIS
SULFUR SOURCE • SUPPLY SULFUR FOR BIOSYNTHESIS OF CYSTEINE, METHIONINE AND VITAMINS (BIOTIN, LIPOIC ACID, COENZYME A) • TYPES: • ORGANIC-CYSTEINE AND METHIONINE • INORGANIC H2S, SO4-2 • H2S ASSIMILATED DIRECTLY, HOWEVER, ONLY PRESENT AND STABLE UNDER ANAEROBIC CONDITIONS; OXIDIZES SPONTANEOUSLY IN THE PRESENCE OF AIR. • SO4-2 STABLE IN AIR. MUST BE REDUCED BY ASSIMILATORY SULFATE REDUCTION BEFORE INCORPORATION INTO ORGANIC COMPOUNDS (SEE DIAGRAM BELOW). • ACTIVATION OF SULFATE: SO4-2 + 2 ATP ADENOSINE-3’-P-5’ PHOSPHOSULFATE • (PAPS) • REDUCTION TO SULFITE: PAPS + NADPH SO3- + AMP-3’-P • 3. REDUCTION TO SULFIDE: SO3- + 3 NADPH H2S
FUNCTION AND ACTIVITIES OF BACTERIAL CELL MEMBRANE FUNCTION CONTAINS CYTOPLASM AND PROTECTS CELLULAR PROTEINS AND CHROMOSOMES ACTIVITIES 1. NUTRIENT TRANSPORT (UPTAKE) 2. ENERGY GENERATION 3. BIOSYNTHETIC ACTIVITIES 4. PROTEIN SECRETION 5. SIGNAL TRANSDUCTION
PHOSPHOENOLPYRUVATE : SUGAR PHOSPHOTRANSFERASE SYSTEM(PEP : SUGAR PTS) • MULTI-ENZYMIC SYSTEM WHICH CATALYZES SIMULTANEOUS UPTAKE AND PHOSPHORYLATION OF SUGARS. • ENERGIZED BY PEP SUCH THAT HIGH ENERGY PHOSPHATE (~ P) TRANSFERRED TO SUGAR DURING TRANSPORT YIELDING SUGAR PHOSPHATE (SUGAR-P) WHICH IS RELEASED INTO CYTOPLASM. • MECHANISM A. REACTION OF GENERAL PTS ENZYMES - ALL PTS SYSTEMS CONTAIN TWO GENERAL ENZYMES (ENZYME I AND HPr) LOCATED IN CYTOPLASM (SOLUBLE PTS PROTEINS) - ENZYME I CATALYZES PEP-DEPENDENT PHOSPHORYLATION OF HPr - HPr: HEAT-STABLE PROTEIN; CARRIER PROTEIN FOR ~P IN PTS SYSTEM; ACCEPTS ~P FROM PEP AND DONATES ~P TO SUGAR SPECIFIC ENZYMES OF PTS - ALL SUGARS TRANSPORTED BY PTS SYSTEM IN E. COLI REQUIRE PRESENCE AND ACTIVITY AND ENZYME I AND HPr
PHOSPHOENOLPYRUVATE : SUGAR PHOSPHOTRANSFERASE SYSTEM(PEP : SUGAR PTS) - continued 3. MECHANISM (continued) B. REACTIONS OF SUGAR-SPECIFIC PTS ENZYMES - FOR EACH SUGAR TRANSPORTED BY PTS MECHANISM, THERE ARE 1-2 ADDITIONAL ENZYMES INVOLVED. - THESE ENZYMES ARE SPECIFIC FOR EACH SUGAR AND ARE SYNTHESIZED ONLY WHEN E. COLI IS GROWN ON THAT PARTICULAR SUGAR. - ENZYME II: 1. PARTICULATE ENZYMES THAT FUNCTION AS BOTH TRANSPORT CARRIERS AND PHOSPHORYLATING ENZYMES. CATALYZE SIMULTANEOUS UPTAKE AND PHOSPHORYLATION OF SUGAR. 2. ACCEPT ~P FROM HPr~P (e.g. MANNOSE, PTS) OR FROM ENZYME III~P (e.g. GLUCOSE, FRUCTOSE, PTS)