School of Science and Technology, Online Counseling Resource…
Online Counseling Resource
YCMOU ELearning Drive…
School of Architecture, Science and Technology
Yashwantrao Chavan Maharashtra
Open University, Nashik – 422222, India
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School of Science and Technology, Online Counseling Resource…
OC-SBT081-CP01-04
Introduction
Programmes and Courses
 SEP – SBT081 – Unit 01
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Credits
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Academic Inputs by
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Arun Punaji More.
M.Sc. (Microbiology)
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Experience: 11 Years
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[email protected]
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School of Science and Technology, Online Counseling Resource…
How to Use This Resource

Counselor at each study center should use this presentation to deliver
lecture of 40-60 minutes during Face-To-Face counseling.
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Discussion about students difficulties or tutorial with assignments should
follow the lecture for about 40-60 minutes.
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Handouts (with 6 slides on each A4 size page) of this presentation should
be provided to each student.
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Each student should discuss on the discussion forum all the terms which
could not be understood. This will improve his writing skills and enhance
knowledge level about topics, which shall be immensely useful for end
exam.
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Appear several times, for all the Self-Tests, available for this course.
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Student can use handouts for last minutes preparation just before end
exam.
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Learning Objectives
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After studying this module, you should be able to:
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Describe the general characteristics of Archaea.
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Enlist examples of Archaea
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Describe significances of some members of physiological groups of
Archaea.
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School of Science and Technology, Online Counseling Resource…
Introduction
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In modern taxonomy, the organisms are divided
into number of classes on the basis of rRNA
sequences.
The organisms are placed, according to this
taxonomic scheme, into three domain as follow:
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Eukarya
Archea
Bacteria
In previous taxonomic scheme, the organisms
were divided into Eukaryotes, prokaryotes; and
prokryotes were further divided into
archaeacteria and bacteria.
In this presentation we will learn some
interesting features of archaebacteria.
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School of Science and Technology, Online Counseling Resource…
Archaea-1
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The term “archaebacteria” is not used now a
day, in the modern taxonomy, but reffered to as
“Archaea”.
The “Archaea” ,though share some
morphological features of baceria, are distinct
group of prokaryotes on the basis of their rRNA
sequences.
Besides the morphological features the members
of archaea also possess the almost same
prokaryotic cell structure as that of bacteria with
some distinct differences from the bacteria.
The Archaea is divided into two phyla:
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Crenarchaeota
Euryarchaeota
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Archaea-2
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The phylum euryarchaeota contain three
groups having different physiology such
as aerobic, anaerobic, acidophilic and
alkaliphilic.
Methanogens are strict anaerobic.
Halobacterium salinarum extreme
halophilic and aerobic Archaea.
Thermoplasma lack cell wall and grow at
high temperature and low pH.
Picrophilus is example of thermoplasma.
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Archaea-3
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Characteristics of Archaea:
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The cell walls of Archaea lack peptidoglycan.
Archaea reproduce by binary fission, budding,
and fragmentation.
No members of Archaea is known to cause
disease in humans and animals.
The important members of Archaea are
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Methanogens
Thermophiles
Halophiles
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Archaea-4
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Methanogens:
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Methanogens are obligate anaerobic microorganisms.
Methanogens can convert CO2 ,H2 and organic acids into
methane gas.
Methanogens play important role in converting the
wastes in ocean, ponds and river bed into methane.
Therefore they have got industrial application in
sewage treatment.
The methane produced from sewage is used to
generate electricity.
In India, in the rural area, domestic gobar gas plant
(dug gas plants) are widely used to produce methane
as cooking gas.
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Archaea-5

The Methanogens show fluorescence when
expose to UV light.
Fig:: Fluorescing methanogens under UV microscope
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Archaea-6

The Archaea are also divided for the
convenience of their identification into
following physiological groups:
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Thermophiles
Acidophiles
Halophiles
These physiological groups are collectively
called as extremophiles.
Extremophiles are defined as
microorganisms which require extreme
conditions of temperature, pH and salinity.
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Archaea-7
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Thermophiles:
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These members of archaea can grow at
temperature more than 45°C.
Some of the thermophiles can even grow at
the temperature of 80°C.
Since the enzymes and proteins of
thermophiles can remain stable above 80°C,
they have got many industrial applications.
For example, the RNA plymerase from
thermophilus aquaticus is used in genetic
engineering, in the polymerase chain reaction.
The ability of thermophiles to grow at
extremely high temperature is used to isolate
and identify the thermophiles in laboratory.
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Archaea-8

Thermophiles:
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For example, the RNA plymerase from
thermophilus aquaticus is used in genetic
engineering, in the polymerase chain reaction.
The ability of thermophiles to grow at
extremely high temperature is used to isolate
and identify the thermophiles in laboratory.
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Archaea-9

Halophiles: The halophiles have got absolute
dependency on a concentration of NaCl
greater than 9%.
 The halophiles require such high
concentration of NaCl to maintain the
integrity of their cell wall.
 Some halophiles can survive up to the
35% concentration of NaCl.
 Most halophiles can grow and reproduce
in range of 17% to 23% of
concentration of NaCl.
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Archaea-10

Halophiles: This capability of growing at higher
concentration of NaCl is used to isolate
the halophiles in pure culture and help
to identify the halophiles in laboratory.
 The example of halophile Archaea is
Halobacterium salinarum.
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School of Science and Technology, Online Counseling Resource…
What We Learn...
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The characteristic features of Archaea.
Different physiological groups of Archaea.
Natural habitats of Archaea.
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School of Science and Technology, Online Counseling Resource…
Critical Thinking Questions

How the Archaea can grow in extreme
conditions such as high temperature, high
salt concentration?
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Hints For Critical Thinking Questions

Enzymes which remain stable at high
temperature.
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Study Tips
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Book
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Title: Microbiology
Author: Robert W Bauman
Publication: Benjamin Cummings, San Francisco
Book
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Title: Microbiology, An Introduction
Author: Tortora and et al.
Publication: Pearson education, Singapore
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School of Science and Technology, Online Counseling Resource…
End of the Presentation
Thank You!
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