Kingdom monera. Extra Stroke lectures A,B & C part

Transcription

1 Kingdom monera Extra Stroke lectures A,B & C part

2 Microbiology is the study of microorganisms, which are unicellular or cell-cluster microscopic organisms. A person who specializes in the area of microbiology is called a microbiologist.

3

4

5

6 We have probably only studied about 1% of all of the microbes on Earth.

7 Resolving power of Human Eye 100mm So organism less than 100mm (0.1mm] are called Microbes. Leeuwenhoeck Father of Microscopy He first sketched the microorganisms. Cellular microorganisms are generally measured in units of Micrometer ( mm ) which is one thousandth part of a millimeter (mm) Acellular microorganisms are generally measured in units of nanometer ( nm) which is one thousandth part of a micrometer (mm)

8 Father of Microbiology : Leeuwenhoek Father of Bacteriology : Leeuwenhoek Founder of modern Bacteriology : Pasteur Founder of modern Microbiology : Pasteur Father of microbial techniques : R. KOCH Leeuwenhoek The first microbiologist Nicholus appert : Father of Food microbiology Fuch : Father of Dairy bacteriology Father of chemotherapy : Ehrlich Father of Immunology : Edward Jenner

9 Robert Koch Considered to be the founders of medical microbiology. Cohn first to formulate a scheme for the taxonomic classification of bacteria. ******Carl woese Three domains, 16s rrna

10 BACTERIOLOGY The science dealing with the study of Bacteria is called as BACTERIOLOGY. Antoine vonn Leeuwenhoek discovered the Bacteria in the rain water and called them wild Animalcules. Bacteria term coined by Ehrenberg. The word bacterium is of Greek origin meaning Little rod or Little stick

11 Kirchar was the first man to recognize the significance of bacteria and other microbes in disease. Muller coined certain words Bacillus, Vibrio and Spirillum which are now used as generic names in Bacteriology.

12 In 1695 Leeuwenhoek published his work in his book titled THE SECRETS F NATURE DISCOVERED BY A.V. LEEUWENHOEK. The importance of Leeuwenhoek's animalcule was realized about 200 years later when Louis Pasteur demonstrated their great role in fermentation and Decay. He declared that all putrefaction is due to the action of microbes

13 Pasteur developed a technique where he heated a wine-bottle at C for a short period and thus killed undesirable Bacteria. The process is now called as PASTEUTIZATION. It is generally used for temporary preserving milk (made free from pathogenic bacteria ; not from all bacteria) In which involves Two methods heating at 71.6 C for seconds. (high temperature short time method / HTST) heating at 62.5 C for 30 Minutes. (Low temperature Long time method / LTLT)

14 Pasteur studied a number of fermentations very carefully. He also demonstrated that Life is possible without air. He showed that certain Bacteria could live with out oxygen which was, till then considered to essential for use. Pasteur introduced the term Anaerobic & Aerobic.

15 Robert KOCH isolated Bacteria causing anthrax and tuberculosis and established Koch's postulates.

16 This was the first time a Bacterium had been proved to be the cause of an animal disease.

17 KOCH`S POSTULATES Isolation of microbes from diseased animal. Isolated microbes cultured in laboratory in culture medium. injected these microbe in experimental animals. and observed clinical symptoms of disease. Isolation of same microbes from the blood of experimental animals. KOCH was awarded noble prize in 1905.

18 Some Significant discoveries of Bacterial forms: GONOCOCCUSS by NEISSER STAPHYLOCOCCUS By Ogston BACILLUS By KOCH (Causing T.B. and Anthrax) VIBRIO By KOCH (causing Cholera) BACILLUS BY LOEFFLER (causing Diphtheria) PNEUMOCOCCUS By FRANKEL (causing Pneumonia) SPRICHAETE By SHAUDIN & HOFFMANN (causing syphilis)

19 Joseph Lister - First obtained pure culture of Bacteria. Pure culture are those bacterial colonies which are having only one kind of bacteria (developed from a single bacteria) KOCH obtained pure cultures of Bacteria causing tuberculosis. HANSON devised a dilution method for obtaining pure cultures of microbes.

20 GERM THEORY OF DISEASE : Proposed by Louis Pasteur. The germ theory of disease confirming the fact that the infectious diseases were caused by micro organisms. Use of carbolic acid (Phenol) and antiseptics and antiseptic surgery was discovered by Joseph Lister.

21 Important Note Scientists claim that till now only about 4000 species of bacteria have been cultivated and studied. Jacob Henle teacher of R.Koch, in 1840 formulated for the first time the conditions to be fulfilled for proving the causal relation of a disease with specific microbe. Koch earned great fame due to his work on tubercular bacilli. (Noble Prize 1905) French chemist Pasteur s fame reached a climax with the discovery of antirabies vaccine (1885)

22 Important Note Koch s laboratory, first time : Used agar as culture medium (agar replaced gelatin) Designed petri dishes for microbe culture Lister first time got pure cultures of Lactic acid bacteria Chamberland constructed a porcelain filter which is bacteria proof filter. Pasteur institute Paris Paul Ehrlich used term Chemotherapy, He synthesized organic arsenic compound (Salvarsan) which is used to treat Syphilis. (Noble prize 1908)

23 Important Note In 1935 Domagk discovered a dye Prontosil (sulfanilamide molecule / Sulpha drugs) which is having antibacterial properties. They have been extensively used to control various bacterial infections before the antibiotics were discovered. (Nobel prize 1939)

24 Kingdom monera Extra Stroke lecture Part - B

25

26 CLASSIFICATION OF BACTERIA Cohn placed the Bacteria and blue green algae both in Schizophyta Nogeli placed the Bacteria in Schizomycetes. Stainer & Von Neil (1941) replaced the term schizophyta by Monera. WHITTAKER (1969 ) proposed a five kingdom classification and placed BGA and Bacteria in the Kingdom Monera Bergey divided the plant kingdom into five phyla namely Prosophyta, Thallophyta, Bryophyta, Pteridophyta and Spermatophyta and placed Bacteria and viruses in prosophyta.

27 The organisms included under the kingdom Monera are called monerans The kingdom Monera includes prokaryotic organisms the bacteria, archebacteria and the Cyanobacteria (BGA) The Bacteria have been divided into nineteen groups which include bacteria of all kinds.

28 In bacterial taxonomy a rank above kingdom level has been created, called Domain In case of bacteria, a species is defined as a collection of strains which resemble each other in many characteristics and differ significantly from other collections of strains. A strain is defined as the descendents of a single colony of a pure culture.*********** A bacterial species comprises a number of strains which are closely similar, differing in one or few characteristics. Thus the concept of bacterial species is different from the species concept applicable to higher organisms. ***

29 Bacteria lack, generally, a sexual mechanism as found in higher organisms and, therefore, the definition of a bacterial species is not so rigid, rather it leaves considerable amount of freedom to the taxonomist to create new species on the basis of even one or few differences in characteristics.

30 Domain Archaea Prokarya Eukarya Archaea Kingdom Euryarcheota Kingdom - Crenarcheota

31 Prokarya Cyanobacteria Eubacteria Eukarya Kingdom Plantae Kingdom - Fungi Kingdom - Animalia

32 On the basis of rrna homology, Woese (1993) proposed a Phylogenetic tree which includes 7 Kingdoms. (not universally recognized) Cavaler and Smith proposed 8 Kingdom classification, which includes two Empires Bacteria and Eukaryota. In this classification the eukaryotic microbes have been divided into three kingdoms : Archaezoa, Chromista and Protozoa. The eight kingdoms are Eubacteria, archebacteria, archaezoa, chromista, protozoa, plantae, fungi and animalia. The bacterial classification largely based on the variations in morphological, physiological and biochemical properties, staining characteristics and sometimes serological properties. ******(artificial) **********No phylogeny clearly

33 Modern bacterial classification is based upon following characteristics : G+C % DNA DNA Hybridization DNA sequencing 16s rrna Homology Serological properties

34 Bergey s manual authentic source of exhaustive information about all known bacteria for more than 80 years. It was first published in According to Bergey's manual the bacteria are placed in four divisions : Gracilicutes : Complex gram negative type cell wall Firmicutes : Cell wall of gram positive type Tenericutes : Cell wall absent Mendosicutes : Cell wall generally present but does not contain peptidoglycan.

35 Drawbacks of classification of Bergey's manual Many taxa are not phylogenetically related Some of the characters given great weightage which are not very much phylogenetically significant Mycoplasma are placed under tenericutes but rrna studies indicate their close relationship to gram positive bacteria.(firmicutes)*******

36 OCCURRENCE AND DISTRIBUTION OF BACTERIA Bacteria are ubiquitous in distribution These are found in soil, water and air. Rain water is usually free from Bacteria Maximum of Bacteria are expected in soil because soil contains water, air, minerals, organic matter. Some Bacteria are present in hot water spring at a temperature of 78 C While others live in ice at a temperature of 190 C. Thermophilic sulphur bacteria / Marine archebacteria are found at temperatures of C, They are found in hot springs of deep seas.

37 Important Note Number of micro organisms in Soil True bacteria Actinomyces Protozoa Fungi Algae Most soil microbes occur in the upper 5 15 cm of soil First noble prize in field of microbiology 1901, Von behring for the research on Diphtheria antitoxin.

38 MORPHOLOGY OF BACTERIA (A) SIZE : A Bacterial cell measures 2 to 10µ in length and 0.2 to 1.5µ in diameter. Smallest Bacterium Dialister pneumosintes (0.15µ 0.3µ long) Largest bacterium Beggiatoa Mirabilis (several cm in length, 16 45µ diameter) *Bacteria Epulopiscium fishelsohnii 80 µm in diameter and 200 µm in length (discovered in 1991) *Bacteria Thiomargerita namibiensis 750 µm in diameter and is visible to the unaided eye.

39 FUNGI LIKE BACTERIA : They are like branched fungus mycelium These Bacteria also called RAY-FUNGI. Ex Actinomyces and Streptomyces

40

41 CHEMICAL COMPOSITON OF BACTERIA Chemically a Bacterial cell composed of 70% water, 21% protein, 4.5% nucleic acids (3.6% RNA and 0.9% DNA) 3% lipids and 1.5% polysaccharide.

42

43

44 ULTRASTRUCTURE OF BACTERIA (A) FLAGELLA : On the basis of flagellation the Bacteria are differentiated into the following categories ATRICHOUS : Flagella absent Ex. Lactobacillus, Spirochaete MONOTRICHOUS : Only one flagellum attached at one pole of the Bacteria. Ex. : Pseudomonas, Vibrio LOPHOTRICHOUS : Two of more flagella attached only at one end. (a tuft of flagella) Ex : Pseudomonas

45

46 AMPHITRICHOUS : They possess a tuft of flagella at both the ends. Ex.:AQUASPIRILLUM PERITRICHOUS : Flagella distributed all over the surface of the cell. Ex.:Bacillus, E.Coli

47

48

49 Bacterial flagella are made up to flagellin protein Each flagellin molecule is about 40 A in diameter and is similar to Actin of muscles. Bacterial flagellum fundamentally differs from Eukaryotic flagellum in not having arrangement. Bacterial flagella is a wavy helical or rope like structure A cross section of the Bacterial flagellum reveals that there are 8 flagellin molecule surrounding a central hollow cylinder. The Bacterial flagellum is usually 4-5 µ long and A in diameter. Sometimes it is about 10 times longer than the cell it self.

50

51

52

53 (B) PILI OR FIMBRAE A Bacterial cell may be covered by numerous hair like proteinaceous non helical, filamentous structures called pili or Fimbrae. They are extension of cell wall and made up of pillin proteins. Pili or Fimbrae helps in conjugation and play a major role in infection by facilitating attachment of Bacteria cell to the host cell. They are generally found in wall of gram negative Bacteria When pili takes part in conjugation called as sex pili.

54

55

56 (C) SURACE ADHERENTS (CAPSULES AND SLIME LAYERS) The Bacteria cell may be covered by a polysaccharide coat. When this covering is in the form of loose mass, it is called as slime or slime layer. When it is in the form of a well defined cover, it is called as capsule. When the capsule is more then 0.2µ thick, it is described as macro capsule. When the capsule is less then 0.2µ thick, it is described as microcapsule. Most of the Bacterial capsules are made up of polysaccharides

57 These may be made up of single Kind of sugar (Homopolysaccharides) ex - Streptococcus or several kinds of sugar (Heteropolysaccharides) ex - Klebsiella pneumoni The capsule protects Bacterial cell from phagocytosis, drying, & attack of Bacteriophage. The virulence in a Bacterium is also due to the presence of Capsule. Note in Bacillus anthrasis the capsule is made up to amino acids (polypeptides).

58

59 (D) CELLWALL: The Bacterial cell wall made up of peptidoglycan or Glycopeptides or micro peptide or murein. The mucopeptide is a polymer of two amino sugars namely: N Acetyl glucosamine (NAG) and N Acetyl muramic acid (NAM)). The units of there sugars are alternatively held in B- 1, 4 linkages. This forms the backbone structure of cell wall in all prokaryotes. The mucopeptide chains are laterally joined for structural rigidity by amino acids.

60

61

62

63 NAM NAM NAM

64 In many gram +ve Bacteria and actinomycetes these four amino acids are L -Alanine, D-Glutamic Acid, L-Lysine, D Alanine, on the other hand in gram -ve Bacteria, myxobacteria, and BGA DIAMINOPIMALIC ACID (DAP) is present in place of Lysine.

65 Christian gram on the Basis of Staining divided Bacteria into two groups namely gram +ve and gram Ve Gram Staining technique - The Bacterial smears are heat fixed on a slide. They are then stained with crystal violet (Primary stain) followed by Iodine (Mordant). They stain deep purple. When treated with alcohol / acetone, the gram positive Bacteria retain the colour whereas the gram negative Bacteria is Decolorize.

66 GRAM POSITIVE GRAM NEGATIVE 1. Cell wall thick ( Ă) Cell wall thin (100Ă) 2. Cell wall more rigid Cell wall less Rigid 3. Cell wall single layered Cell wall three layered 4. Cell Wall Homogenous Cell wall Heterogeneous % Peptidoglycan in cell wall 10 20% Peptidoglycan in cell wall 6. Cell wall made-up of mucopeptide Cell wall made up of lipoprotein, Lipopolysaccharide and mucopeptide. 7. Teichoic acid present (5 10%) Teichoic acid absent 8. Spore producing forms included No spore producing form 9. Flagellum usually absent Flagellum usually present 10. Not soluble in 1% KOH Soluble in 1% KOH 11. May produce exotoxins May produce Endotoxins 12. Sensitive to penicillin Not sensitive to penicillin. 13. Outer envelop absent Outer envelop present 14. Low lipid content High lipid content (10 12% of by weight)

67

68 Structure of the Gram-positive Cell Wall

69 The Gram-negative outer membrane(1)

70 IMPORTANT NOTE (1) Teichoic Acids present in cell wall of gram positive Bacteria are acetic polymers consisting of a carbohydrate, phosphate and an alcohol. Teichoic acid have several functions such as binding metals, acting as receptor sites for some viruses and maintaining cell at low ph to prevent degradation of cell walls by self produced enzymes. (2)Outer envelop present in gram negative Bacteria is a Bilayered structure consisting chiefly by phospholipids, proteins and Lipopolysaccharide (LPS).

71 IMPORTANT NOTE Function of outer envelop : (1) Prevent the entry of Harmful and toxic chemical that could damage the cell. (2) Maintaining the permeability to nutrient by channels made up of porin proteins. (3) Protective function. 3. Some Bacteria lack a cell wall like protoplasts, sphaeroplasts,l - form Bacteria; The Spheroplasts are bacteria with damaged or partly lost cell wall.

72 IMPORTANT NOTE The form (Lister form) Bacteria were first isolated by Klineberger. They are irregular shaped resembling Mycoplasma. They may be gram positive or gram negative. They multiply by budding or fission forming elementary corpuscles. They are resistance to penicillin. 4. Our present knowledge of the basic wall structure of Bacteria has come through the action of Lysozymes and the antibiotic penicillin.

73 Bacterial Cell membrane & other cell components..continue