2. Introduction
Metabolites are the intermediates and products of
metabolism, are typically characterized by small
molecules with various functions.
Metabolites can be categorized into
1) Primary metabolites.
2) secondary metabolites.
3. The word metabolism is derived from the Greek word
“Metabolismos” or from the French word métabolisme.
Metabolism and metabolic pathways have been studied over
several centuries and has moved from examining whole animals
in early studies, to examining individual metabolic reactions in
modern biochemistry and molecular biology.
History
4. What are metabolites ?
Metabolites are the intermediates & products of metabolism.
The term metabolite is usually restricted to small molecules.
A primary metabolite is directly involved in the normalgrowth,
development, and reproduction.
Examples:1.Carbohydrates 2.Proteins3.Lipids
4.Nucleic acids
A secondary metabolite is not directly involved in thoseprocesses,
but usually has important ecological function.
Examples include antibiotics, mycotoxinsetc.
5. primary metabolites are involved in maintaining normal
physiological processes thus, it is often referred to as a
central metabolite.
Essential for proper growth, development,
and reproduction.
Examples include alcohols such as ethanol, lactic
acid.
Primary Metabolites
6. Aspergillus niger is used in industrial microbiology for
mass production of citric acid. (primary metabolite).
7. Secondary metabolites is a term for pathways for small
molecule and products of metabolism that are not absolutely
required for the survival of the organism.
A secondary metabolite has an important ecologicalfunction.
Examples include antibiotics, mycotoxins etc.
They are classified on the basis of
1. chemical structure
2. chemical composition
3. solubility in various solvents
4. pathways by which they are synthsized
Secondary Metabolites
8. Why secondary metabolites are
of no use to the organism?
Because they are
synthesized late in growth
cycle in stationary phase
(idiophase).
Secondary metabolites are structurally
diverse low molecular mass molecules
that are not essential for the growthand
survival of the producing organisms.
Secondary metabolite serve to increase
the fitness of the producing organisms
and to decrease the fitness of
surrounding organisms.
Metabolites play a role in regulation
and process of sporulation
Secondary Metabolites
10. Categories of secondary metabolites
Major categories of secondary metabolites
1) Mycotoxins
2) Antibiotics
3) Alkaloids
4) Amino acids
5) Steroids
6) Vitamins
11. Difference between primary and secondary
metabolites
Primary metabolites Secondary metabolites
They are involved in normal
growth, development and
reproduction.
They are not directly involved
in the normal growth,
development and
reprodµction.
Examples for primary
metabolites are carbohydrates
, fats and proteins.
Examples for secondary
metabolites are alkaloids,
tannis, resins, gums
and latex etc.
They are not poisonous. Some of these compounds
are poisonous.
12. Mycotoxins
Mycotoxins refer to the toxic secondary metabolites.
They are neither necessary for growth nor the development of thefungi.
Some of these very severe effects on animal, plant and microbialsystem
(fungal food poisoning-mycointoxication).
Symptoms of a mycotoxicosis depend on:
The type of mycotoxin
The concentration
As well as age
Health
And sex of the exposed individual
14. Antibiotics
The term ‘antibiotic’ was coined by selman waksmanin
1942.
The secondary metabolites isolated from microbes and
exhibits either antimicrobial(antibacterial, antifungal,
antiprotozoal), antitumor and antiviral activities used to
be called as antibiotics.
It is used to treat infections caused by microorganisms,
including fungi and protozoa.
16. 1.Penicillin
Penicillin is a secondary metabolite or idiolite ; not requiredfor
growth of fungus.
Production of fungal biomass occurs in growth phasecalled
trophophase.
Accumulation of penicillin occurs in idiophase.
Its production only begins after near exhaustion of carbonsource.
High levels of glucose repress penicillinproduction.
17. 2. Cephalosporins
Cephalosporin are a group of broad spectrum ,semi-syntheticβ-lactam
antibiotics derived from the mould Cephalosporium acremonium.
They are divided into some groups-cephalosporin N and C are
chemically related to penicillins and cephalosporin
18. 3.Streptomycin
Discovered by selman waksman.
Streptomycin is a secondary metabolite produced by streptomyces
griseus an actinobacterium.
Used in treatment of diseases; infective endocarditis, tuberculosis,
tularemia, in veterinary medicine for use against gram negative bacteria
in large animals.
19. 4. Griseofulvin
Griseofulvin also known as Grisovin is an antifungal drug that
is administered orally.
It is derived from the mould Penicillium griseofulvum andstreptomyces
griseus .
It is used both in animals and in humans, to treat fungal infections of the
skin and nails.
20. Alkaloids
Alkaloids are a group of naturally occurring chemical
compounds which mostly contain nitrogenatoms.
Beside carbon and hydrogen molecules of alkaloids may contain-
• Sulfur
• Rarely chlorine
• Bromine Or phosphorus
22. A steroid is a biologically active organic compound with fourrings
arranged in a specific molecular configuration
Rhizopus arrhizus :- hydrolytes progesterone forming another steroid
with introduction of oxygen.
Cunnighamella blakesleeana :- can hydroxylate steroid cortexolome to
form hydrocortisone.
Rhizopus nigricans :- numerous similar transformations are carriedout
to produce various steroid derivatives for medicinaluses.
Steroids
24. AMINO ACID CULTURE
Tryptophan Escherichia coli
Threonine Streptomyce
s
racemosus
Phenyl alanine Corynebacteriu
m glutamicus
Amino acids are secondary metabolites
25. References
Principles of microbiology, by ronald atlas
A text book of basic and applied microbiology,
K R aneja , pranay jain , raman aneja
Web sources
Wikipedia
