© 2007, YCMOU. All Rights Reserved.1 Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan

© 2007, YCMOU. All Rights Reserved. 1

Online Counseling ResourceYCMOU ELearning Drive…

School of Architecture, Science and TechnologyYashwantrao Chavan Maharashtra

Open University, Nashik – 422222, India


OC-SBT081-CP01-01

Introduction

Programmes and Courses SEP – SBT081 – Unit 01

School of Science and Technology, Online Counseling Resource…


Credits

Academic Inputs by Arun Punaji More.

M.Sc. (Microbiology) Experience: 11 Years [email protected]



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.

Discussion about students difficulties or tutorial with assignments should

follow the lecture for about 40-60 minutes.

Handouts (with 6 slides on each A4 size page) of this presentation should

be provided to each student.

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.

Appear several times, for all the Self-Tests, available for this course.

Student can use handouts for last minutes preparation just before end

exam.



Learning Objectives

After studying this module, you should be able to: Describe Morphological features of bacteria. State examples of bacteria showing different

types of morphology. Classify bacteria depending upon their

morphology.



Introduction Bacteria exhibit variety of morphological

forms. The morphological forms of bacteria can

be used in identification of the bacterial species.

Identification of bacteria is essential to classify bacteria, to diagnose a pathogenic bacteria in a particular disease for proper treatment of the disease.

It is therefore interesting to know the different morphological features of bacteria.



Morphology of Bacteria-1 Bacteria exhibit various shapes and range from

1μ to 10μ. The bacteria show three basic shapes such as Rod shaped bacteria or bacilli, spherical or cocci shaped bacteria and Spiral shaped bacteria. Bacteria show some slight variations in these

shapes. For examples rod shaped bacteria show slight

curved ends giving them comma shaped appearance; this is called as comma shaped bacteria.



Morphology of Bacteria-2 The typical morphological features of

bacteria are shown in the following figure.



Morphology of Bacteria-3 Vibrio cholerae is example of comma

shaped bacteria. Some bacteria show shapes

intermediate between spherical and rods; these are called as cocco-bacilli.

Spirilla and spirochetes are examples of spiral bacteria.

Besides these shapes, bacterial morphology is also described with their some special appendages such as pilli, flagella, and resistant forms, spores.



Morphology of Bacteria-4 The motility of bacteria can be seen

by hanging drop technique and is used to identify and classify bacteria into motile and non motile bacteria.

Flagellum is organ of motility and give bacteria capability to move toward nutrient riched environment for their survival

Fig: Bacterial cell with polar flagella



Morphology of Bacteria-5 Morphology of bacteria can be observed

after staining them with Gram's stains under compound microscope.

Here the bacilli are arranged in chains and endospores can also be seen.

Fig: Bacilli stained with Gram's stain.



Morphology of Bacteria-6 Spherical or cocci shaped bacteria:-

The bacteria which show spherical morphology are called as cocci.

Cocci show different cell arrangements which help further to classify them into two genus i. e. staphylococci and streptococci.

The cocci which appear in bunches are called as Saphylococci.

The cocci which appear in chains are called as Streptococci.

Streptococci and Staphylococci are Gram positive bacteria.

Many species of streptococci possess capsule which is a major virulence factor of these bacteria.



Morphology of Bacteria-7

Some bacteria show intermidiate morphology between rod and cocci; these are called as coccobacilli.

Enterobacter earogenes are coccobacilli; they one of the major causative organisms of nosocomial infections.



Morphology of Bacteria-8 Gram staining of bacteria culture

differentiate the rod shaped bacteria from the spherical shaped bacteria.

Fig: Gram stained smear of rod shaped and spherical shaped bacteria.



Morphology of Bacteria-9 Corynebacteria show pleomorphic

morphology. Following Figure shows Corynebacteria

diphtheria arranged in chines letter forms.

Fig: Corynebacteria diphtheriae



Morphology of Bacteria-10 Though the majority of cocci are Gram

positive by nature there are few exception.

The species of Niesseria are Gram negative bacteria which appear in pairs; therefore called as Gram negative diplococci.

This typical morphology of Niesseria in urethral pus formed a primitive diagnosis of disease, gonorrhea.



Morphology of Bacteria-11 The genus Niesseria include two

medically important pathogens i.e. N. gonococci and N. meningitidis.

The gonococci show typical kidney shaped or bean shaped morphology as shown below.

Fig: Bean shaped gonococci arranged as dipococci.



Morphology of Bacteria-12 Spiral bacteria:- Spirilla are spiral stiff

bacteria.

Fig: spirilla



Morphology of Bacteria-13 Spiral shaped bacteria:-

Spirochete is another example of spiral shaped bacteria.

Unlike the spirilla they are flexible. The spirochete has three genera:

Treponema Borrelia Leptospira



Morphology of Bacteria-14 Coccobacilli:-

Bacilli of yersenia pestis are causative agents of bubonic plague. Their another characteristic feature is that they show bipolar staining giving themSafety pin like appearance as shown in the figure.

Fig : yerseneia pestis, coccobacilli



Morphology of Bacteria-15 Bacilli of Mycobacteria appear as long

slender rods as shown below.

Fig: Mycobacteria tuberculosis



What We Learn... Different morphological formed of

bacteria. How morphology of bacteria help to

classify bacteria into different groups. How the morphology of bacteria help in

the diagnosis of some diseases. How to study morphology of bacteria.



Critical Thinking Questions Why bacteria are stained to study their

morphology?



Hints For Critical Thinking Questions Bacterial cells are colorless, and having no

contrast with their surrounding.



Study Tips Book

Title:Title: Microbiology Author:Author: Robert W Bauman Publication:Publication: Benjamin Cummings, San Francisco

Book Title:Title: Microbiology, An Introduction Author:Author: Tortora and et al. Publication:Publication: Pearson education, Singapore


End of the Presentation

Thank You!

Documents

© 2007, YCMOU. All Rights Reserved.1 Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan