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Eubacteria
Bacteria are the simplest and smallest prokaryotic microorganisms. They are ubiquitous, existing everywhere from atmospheric heights of 6km to ocean depths of 5km. Bacteria exhibit a wide range of shapes and many are motile with flagella or pili. They reproduce asexually through binary fission and lack true sexual reproduction. Bacteria play important economic roles through causing diseases, food spoilage, increasing soil fertility through nitrogen fixation, and use in biotechnology and pollution control.
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Eubacteria
- 1. Manjunatha S I M.Sc.(Botany) Universityof Mysore EUBACTERIA AN OVERVIEW
- 2. CONTENTS • Introduction • Generalcharacteristics • Classification • Distribution • Shapes • Cellular organization • Flagella • Bacterial growth • Nutrition • Reproduction • Economic importance • Conclusion • Reference
- 3. INTRODUCTION Bacteria are thesimplest, the smallest and the most successful prokaryotic microorganisms. Bacteria were among the first life forms to appear on Earth. The study of bacteria is known as bacteriology a branch of microbiology. The existence of microbial world was unknown until the invention of Microscope at the beginning of 17th Century, which opened the realm of microorganisms to systematic scientific exploration.
- 5. GENERAL CHARACTERISTICS Cosmopolitan Microscopic innature Size: 0.5-1.0μm Unicellular Prokaryotic type of cellular organization They may be Autotrophic, Heterotrophic, Saprophytic. Cell wall is made up of Peptidoglycan. All cell organelles are absent(except Ribosomes)
- 6. Chlorophyll pigments, ifpresent, are located within involuted cytoplasmic membranes. Mesosomes are present Ribosomes are abundant (70S) Binary fission is the common method of multiplication True sexual reproduction is absent Motile Bacteria may possess one or more flagella.
- 7. CLASSIFICATION According to Bergey’sManual of Systematic Bacteriology, 2nd Edition Eubacteria is divided into 23 Phyla Volume-I covers Deeply branching bacterial groups and Phototrophes Volume-II covers Proteobacteria Volume-III covers The Low G+C Gram Positive Bacteria Volume-IV covers The High G+C Gram Positive Bacteria Volume-V covers Planctomycetes, Spirochaetes, Fibrobacters, Bacteriodetes & Fusobacteria
- 10. Exists everywhere….!!!!!!! Apart fromnormal Environmental conditions….. Occur in atmosphere to an height of about 6 KM & on the sea floor 5 KM below the mean sea level Exist in Hot springs Can survive below Freezing point of water Tolerate to pH range from 0-11 Can tolerate Pressure of 3000-6000 atm Exist as Free living, Parasitic, Symbiotic
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- 13. CELL WALL Cellwall is made up of Peptidoglycan or mucopeptide. Thickness varies from 50-100 A° Function is purely Mechanical On the basis of cell wall character and Staining technique Bacteria’s are classified into a) Gram Positive Bacteria. b) Gram Negative Bacteria.
- 14. SURFACE APPENDAGES FLAGELLA: May bemany times longer than the bacterial cell. It is a hollow cylindrical strand, made up of protein ‘flagellin’ Consists of 3 morphological parts-basal body, hook & filament Based on the number & arrangement of flagella, bacteria are classified into 1) Atrichous (Lactobacillus) 2) Monotrichous (Vibrio) 3) Cephalotrichous (Pseudomonas spp) 4) Lophotrichous (Spirillum volutans) 5) Amphitrichous (Nitrosomonas) 6) Peritrichous (Salmonella) Flagella
- 15. Pili: long &sparse, rigid & tubular-made up of special protein called ‘Pilin’ used for cell to cell or cell to surface attachment Spinae: Rigid & tubular appendages found in some Gram Positive bacteria. Formed of a single molecule of protein ’Spinin’ Helps the bacterium to resist Salinity, pH. temperature etc. PILIFIMBRIAE
- 16. Bacterial growth Involves 4stages 1. Lag phase 2. Exponential phase 3. Stationary phase 4. Death phase
- 17. Autotrophic bacteria Photosynthetic Bacteria Green sulphur Bacteria Chlorobium, Clathochloris Purple Sulphur Bacteria Thiospirillum, Chromatium,Amoebobact er Purplenon-Sulphur Bacteria Magnetospirillum Azatospirillum Cyano Bacteria Nostoc, Anabaena Chemosynthetic Bacteria Sulphur Bacteria Thiobacillus Beggiatoa Iron Bacteria Ferrobacillus, Gallionella Hydrogen Bacteria Pseudomonas spp Nitrifying Bacteria Nitrosomonas Nutrition
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- 19. REPRODUCTION Asexual reproduction 1. BinaryFission 2. Budding 3. Conidia 4. Cysts & Endospores True sexual reproduction is absent, But sexuality is accomplished by interchange of genetic material. 1. Conjugation 2. Transformation 3. Transduction
- 20. Binary Fission Budding& Conidia
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- 25. ECONOMIC IMPORTANCE Harmful activities 1.Causes many diseases Plants Ring spot of Potato --- Xanthomonas solanacearum Citrus canker --- Xanthomonas citri Soft rot of Mango --- Bacterium cartovorus Tundu of Wheat --- Corynebacterium tritici Blight of Bean --- Pseudomonas phaseolicola Animals Plague --- Yersinia pestis Cholera --- Vibrio cholerae Tuberculosis --- Mycobacterium tuberculosis Typhoid --- Salmonella typhi Gastro-enteritis --- Escherichia coli 2. Food spoilage 3. Denitrification by Bacillus licheniformis, Pseudomonas aeruginosa.
- 26. Useful activities. 1. Increasessoil fertility through Ammonification, Nitrification & Nitrogen fixing process. 2. Used in Dairy industries 3. Degradation of Petroleum Hydrocarbons 4. Used in Retting process 5. Decomposition of Dead organisms 6. Insect control 7. Used in Biotechnology for production of various useful products. 8. To control the Pollution.
- 27. CONCLUSION Bacteria are thesmallest living organism s on the Earth. Though having Prokaryotic cellular organization, they show a greater success in survival than any other living organism . We must give credit to Antony van Leeuwenhoek for his discovery which opened the doors of scientific exploration in microbial world. Through their activities Humans are getting many benefits Economically
- 28. REFERENCES • Prescott−Harley−Klein, Microbiology,5th Edition The McGraw−Hill Companies, 2002 • Singh Pande Jain, Textbook of Botany, 4th Edition, Rastogi Publications, Meerut 2011 • www.googleimages.com
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