Fungal primary and secondary metabolism.pdf

1. FUNGAL
PHYSIOLOGY
SUBMITTED BY SUBMITTEDTO
ANCYVARGHESE DR.ARYA P MOHAN
1 ST MSC BOTANY ASST.PROFESSOR
ST.TERESA’S COLLEGE, EKM ST.TERESA’S COLLEGE, EKM
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2. OVERVIEW
INTRODUCTION. – 3
METABOLISM - 4
FUNGAL METABOLISM -5
PRIMARY METABOLISM. – 6-14
SECONDARY METABOLISM – 15-17
REFERENCE. - 18
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3. PHYSIOLOGY ?
• Refers to the nutrition,
metabolism,growth,
reproduction & death of
fungal cells.
• Interaction of fungi with their
biotic & abiotic surroundings.
BENEFITS OF FUNGAL
METABOLISM
• Biogeochemical cycling of carbon in nature.
• In agriculture – mutualistic symbiont
• Detoxification of organic pollutants
• Bioremediating heavy metals
• Economically important industrial commodities
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4. WHAT IS METABOLISM ?
PROCESS BYWHICH BODY CHANGES FOOD
AND DRINK INTO ENERGY .
CATABOLISM
• Break down of molecules to obtain energy.
Eg.Glycolysis
ANABOLISM
• The synthesis of all compounds needed
for the growth.
Eg.Synthesis of proteins from amino acids.
PRIMARY METABOLISM
• Essential for the growth to occur.
Eg.Proteins,Carbohydrates,Nucleic acids…etc
SECONDARY METABOLISM
• Biproducts or intermediates of Primary
metabolism.
• Not absolutely necessary for survival.
Eg.Penicillin,Mycotoxin…etc
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5. SPECIAL ABOUT FUNGAL METABOLISM ……
• Chemotrophic heterotrophs.
• Simple monosaccharides, amino acids, fatty
acids…etc are easily transported across
plasmalemma.
• Degradation done by extracellular enzymes
released through walls.
• Depolymerases of fungi – proteases, pectic
enzymes, lipases, amylases & cellulases.
• Primary metabolism includes, Glycolysis,
Gluconeogenesis,Respiration,and
Fermentation .
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6. CARBON CATABOLISM
• Catabolic pathways are oxidative processes.
• Electrons are removed from intermediate carbon
compounds.
• These are used to generate energy in the form of ATP.
• Catabolic sequence –
Glucose Pyruvic acid = Glycolysis
• Provides fungal cells energy, precursor molecules and
Reducing power (NADPH) for biosynthetic pathways.
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7. GLYCOLYSIS 7

8. GLUCONEOGENESIS
• A process that transforms non-carbohydrate
substrates(such as lactate,amino acids,&
glycerol) into glucose.
• Occur in cytoplasm.
• Provides glucose when dietary intake is insufficient
or absent.
• Also essential in the regulation of acid-base balance,
amino acid metabolism & synthesis of carbohydrate
derived structural compounds.
• Reversal of glycolysis.
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9. WHAT IS NEXT IN AEROBIC CONDITION ?
• Process of utilisation of Oxygen to
breakdown Glucose,amino acids,
fatty acids to produce ATP –
Aerobic Respiration
• Energy yielding pathways in which
inorganic molecules (O2) serve as
terminal electron acceptor = Aerobic
Respiration
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10. AEROBIC RESPIRATION
• Under normal oxidative conditions pyruvic acid derived from glycolysis is
broken down to CO2 & H2O viaTCA Cycle.
• Very littleATP is formed directly from glycolysis orTCA Cycle .
• Instead reduced co-enzymes like NADH2 & NADPH2 are
produced.
• ATP is produced when these co-enzymes are reoxidised.
• Under Aerobic condition, co-enzymes are usually reoxidised by means of
electron transport chain – O2 serves as the terminal electron acceptor.
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11. WHAT IS NEXT IN ANAEROBIC CONDITIONS ?
• Under Anaerobic conditions only glycolysis operates.
• Reduced co-enzymes are oxidised in 2 ways
• 1.Lactic acid fermentation
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12. • 2.Alcohol fermentation
• Growth continues until lactic acid or ethanol accumulate
to toxic levels.
• Energy yielding processes where organic
compounds serve as both electron acceptor and
donor is termed as Fermentation
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13. MIXEDACID FERMENTATION
• It is the metabolic process by which a six
carbon sugar (Glucose C6H12O6 ) is
converted into a complex and
variable mixture of acid.
• A type of anaerobic fermentation seen
common in bacteria;it is also seen in
some anaerobic fungi also.
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14. Aerobic
Respiration
Total no.of ATP
produced = 38
molecules
36 molecules –
formed in Citric
acid cycle
2 molecules
formed outside
the mitochondria.
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15. SECONDARY METABOLISM
• Most active when normal growth is restricted.
• No obvious role in the life of the organism.
• Secondary metabolism = ‘Escape valve’ which removes the intermediates of Primary
pathways when growth stops & converts them into compounds with little or no
physiological activity.
• Used for Competition,Antagonism,Self defense mechanisms.
• Includes a wide range of isoprenoides,alkaloids,antibiotics,toxins…etc
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16. PATHWAYS IN WHICH SECONDARY
METABOLITES ARE PRODUCED
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17. • Secondary metabolites are species – or strain specific .
• They are organic compounds resulting from specific biosynthetic pathways with
low molecular weight, and are not essential for fungal growth but their
natural production.
• Fungi are a rich source of secondary metabolites; among which some
are beneficiary and some others are toxic.
• Beneficiary secondary metabolites – antibiotics ( penicillin), Gibberellin ( a
plant hormone first isolated from a fungi Gibberella fujikuroi
• Toxic secondary metabolites – Alkaloids released by ergot fungus – Claviceps
purpurea
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18. REFERENCE
• Sharma P.D.1998. The Fungi. Rastogi publications
• Madan Mira andThind K.S. 1998. Physiology of fungi.A.P.H.Publishing corporation
• Bilgrami,K.S.andVerma,R.N.1978. Physiology of Fungi. Vikas publishing house pvt ltd.
• Wisecaver,J.H,Slot,J.C,& Rokas,A. 2014.The evolution of fungal metabolic pathways.plos
genetics 10(12),e1004816
• onlinelibrary.wiley.com<doi<ab
Walker,M.andWhite,A.(2017).Introduction to Fungal physiology
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