Classification of micro organisms. Microbiology. B. Pharm SEM V

1. CLASSIFICATION
OF
MICRO-ORGANISMS
- DARSHAN PATIL

2. INTRODUCTION
 Taxonomy is the science that deals with the logical arrangement of living things into
categories.
 Aristotle was the first to group all organisms and categorised them as either plants or
animals.
 E. H. Haeckel (1866), proposed a third Kingdom ‘Protista’, which contained bacteria, fungi &
protozoa.
 Bacteria are lower Protista and algae, fungi and protozoa are classified as higher Protista.
 On the basis of presence of membrane enclosing nucleus (Nuclear Membrane), the organisms
were classified into two types viz. Prokaryotes & Eukaryotes.

3. PROKARYOTES
 A prokaryote is a unicellular organism that lacks a membrane-bound nucleus, mitochondria,
or any other membrane-bound organelle.
 Prokaryotes are asexual, reproducing without fusion of gametes.
 In the prokaryotes, all the intracellular water-soluble components
(proteins, DNA and metabolites) are located together in the cytoplasm enclosed by the cell
membrane.

4. EUKARYOTES
 Eukaryotes are organisms whose cells have a nucleus enclosed within membranes.
 Eukaryotic cells typically contain other membrane-bound organelles such as mitochondria
and the Golgi apparatus, and in addition, some cells of plants and algae contain
chloroplasts.
 Animals and plants are the most familiar eukaryotes.
 Eukaryotes can reproduce both asexually through mitosis and sexually through meiosis and
gamete fusion.
 They have a variety of internal membrane-bound structures, called organelles, and a
cytoskeleton composed of microtubules, microfilaments, and intermediate filaments
 Eukaryotic DNA is divided into several linear bundles called chromosomes

5. PROKARYOTIC VS EUKARYOTIC

6. WHITTAKER 'S FIVE KINGDOM CONCEPT
 Robert H. Whittaker (1969) classified all living beings under five kingdoms based on the
nutrition & absorption of food materials, viz. Monera, Protista, Fungi, Plantae & Animalia.
 Kingdom Monera includes all unicellular prokaryotes (e.g. bacteria, cyanobacteria); Kingdom
Protista includes unicellular eukaryotes (e.g. microalgae, protozoa).
 Whereas Kingdom Fungi, Plantae & Animalia include multicellular and multinucleate
eukaryotic organisms.

8. CLASSIFICATION OF BACTERIA
GRAM POSITIVE BACTERIA
 Gram-positive bacteria take up the crystal
violet stain used in the test.
 A Thick peptidoglycan layer is present
 Teichoic acids and lipoids are present
GRAM NEGATIVE BACTERIA
 Gram-negative bacteria are bacteria that
do not retain the crystal violet stain used
in the Gram staining method of bacterial
differentiation.
 A thin peptidoglycan layer is present
 Teichoic acids or lipoteichoic acids are
absent

9. GROUP OF ORGANISMS
 BACTERIA:
-Unicellular, free-living small organisms, omnipresent.
-Many are pathogenic to plants, animals & humans.
-Important role in natural cycling of elements(soil fertility) & preparation of different
compounds.
 Rickettsia:
-Small gram negative bacilli having properties of both bacteria and viruses.
-Transmitted to humans by arthropods such as ticks, lices, etc
-e.g. Epidemic typhus, Rickettsial pox

10. Actinomycetes:
-Gram positive bacteria, motile, non-capsulated.
-Found in soil and water.
-Rich source of anti-biotics, enzyme, bio-surfactant, enzyme inhibitors and immune-
modifiers.
-Anti-biotics obtained are:- Anthracin, Amino glycosides, Chloramphenicol,
 Fungi:
-Eukaryotic microorganisms, simple oval shaped cells.
-Maybe aerobic or facultatively anaerobic
-Important sources of antibiotics, enzymes, acids, foods, bakery and alcohol
fermentations.
-Certain also cause human diseases like athlete's foot and thrush.
 Protozoa:
-Unicellular, eukaryotic.
-2 to 200 µm in size.
-Some can cause diseases such as malaria and sleeping sickness.

11.  Algae:
-Unicellular or multicellular, aerobic, eukaryotic, mainly occur in aquatic
environments.
-Contain chlorophyll and are photosynthetic.
-Mainly used as food supplements and in pharmaceutical preparations (e.g.
is obtained from different types of algae).
 Viruses:
-Non-cellular, 20 to 300 nm
-Only be seen by electron microscope
-Obligate intracellular parasites, containing DNA or RNA surrounded by sheath
of protein.
-Cause many human diseases including AIDs, hepatitis, polio and chickenpox.

12. REFERENCE
 “A Book of Pharmaceutical Microbiology: Principles and Applications” by Dr. Chandrakant
Kokare (pg no. 1.3-1.7).
 “en.m.wikipedia.org/wiki/Eukaryote” and “en.m.wikipedia.org/wiki/Prokaryote” – Eukaryotes
and Prokaryotes.
 “in.pintrest.com” and “www.bing.com”- Whittaker’s Five Kingdom Classification.
 “en.wikipedia.org/wiki/Gram-negative_bacteria” and “https://en.wikipedia.org/wiki/Gram-
positive_bacteria” - Gram negative and Gram positive bacteria.

13. THANK
YOU