This document discusses bacteria at the kingdom level. It describes their key characteristics including their prokaryotic cell structure, size, shape, cell components, and methods of nutrition and growth. It also covers the important discoveries of van Leewenhoek, Pasteur, and Koch in microbiology. The document discusses the ecological, economic, and medical importance of bacteria and various methods used to control bacteria.

1. The kingdom of bacteria
KINGDOM PROKARYOTAE
Prof. Muhammad Boota Artist 0345-4042530
(Lecturer Biology ASPIRE COLLEGE PATTOKI)

2. KINGDOM PROKARYOTAE
(MONERA)
 Organisms with prokaryotic cells
 Greek Pro: before; karyon: nucleus
 Two categories of bacteria
• Eubacteria
• Archaeobacteria
 Slow progress in study
• Depends of microscope
• Special techniques

3. DISCOVERY OF CELL
 Antonie Von Leewenhoek (1673)
 Developed powerful microscope
 Found microbes in water, infusions, etc.
• Called them animalcules
• Thought they were small animals
• That grew to become large animals
• Actually protists and bacteria
 Found similar “globules”
• In blood, semen, etc.
 Made accurate drawings
 First living cells

4. CONTRIBUTION OF LOUIS PASTEUR
 Major discoveries in microbiology
 Disproved abiogenesis decisively
 Showed that microbes caused disease
 Developed vaccines
• Anthrax
• Rabies
• Fowl cholera
 Pasteurization

5. ROBERT KOCH
 Germ theory of disease
 Isolated bacilli from infected sheep
 Microbes of other diseases
• Tuberculosis
• Cholera
 Four postulates of Germ Theory
• Specific organism in specific disease
• Can be isolated and studied in lab
• Can cause disease in experimental animals
• Can be isolated again from experimental animals
 Developed techniques for study of microbes
• Inoculate, isolation, media preparation, pure cultures, microscopy

6. OCCURRENCE OF BACTERIA
 Widespread in nature
 Found everywhere
• Air, land, water, oil deposits
• Food, decaying organic matter
• Plants, humans, animals
 Type and number is variable
 Some bacteria are present everywhere
• Make up natural “flora”
 Some are found in specific environments
• Hot springs, glaciers, alkaline / acidic soil,
• saline environment, toxic / polluted environments

7. STRUCTURE OF BACTERIA
 Some components are always present
• All have cell membrane
• All have cytoplasm
• All have ribosomes
• All have chromatin body
 Most have cell wall
• Maintains shape
 Some have extra structures
• Capsule, slime, flagella
• Pili, fimbrae, granules

8. SIZE OF BACTERIA
 Highly variable in size
• 0.1 to 600μm
 Smallest is Mycoplasma
• 100-200nm diameter
• Almost equal to largest (pox) viruses
 Escherichia coli is average size
• 1.1 to 1.5 μ
mwide
• 2.0 to 6.0 μ
mlong
 Some spirochetes are long
• 500 μ
mlong
 Staphylococci and Streptococci
• 0.75 to 1.25 μ
m
 Epulopiscium fishelsoni is largest
• Found in gut of surgeonfish (Acanthurus nigrofuscus)
• 600μ
m x 80μ
m (almost equal in size to printed hyphen (-)

9. SHAPE OF BACTERIA
 Three main categories
• Cocci, Bacilli, Spiral
• Also Trichome forming, sheathed, stalked, square,
star-shaped, spindle shaped, lobed, filamentous
 Most have fixed shape
 Some are pleomorphic
• Same species can exist in different shapes

10. SHAPE OF BACTERIA
 Cocci
• Spherical or oval
 Can have different arrangements
 Diplococcus – two cocci together
 Streptococcus – long chains
 Tetrad – four cells
 Sarcina – cube of eight
 Staphylococcus – grape-like irregular clusters
 E.g. Diplococcis pneumoniae and Staphylococcus aureus

11. SHAPE OF BACTERIA
 Bacilli
• Rod-shaped bacteria
 Always divide in one plain
 Diplobacillus – two bacilli
 Streptobacillus – chain of bacilli
 Examples
• Escherichia coli
• Bacillus subtilis
• Pseudomonas

12. SHAPE OF BACTERIA
 Spiral
• Spirally coiled or curved
• Three forms
 Vibrio
• Curved or comma shaped
 Spirillum
• Thick, rigid spiral
 Spirochete
• Thin flexible spiral
 E.g. Vibrio cholera, Hyphomicrobium

13. STRUCTURE OF BACTERIAL CELL

14. FLAGELLA
 Thin, hair like appendages
 Come out through cell wall
 Originate from basal body
• Present under cell membrane
 Made up of flagellin protein
 Help in motility
• Chemotaxis – movement in response to chemicals
 Number and pattern is variable
• Cocci usually do not have flagella
• Bacilli and spiral bacteria have flagella

15. FLAGELLA
 Number and pattern is variable
• Helps in classification of bacteria
 Atrichous – no flagellum
 Monotrichous – single polar flagellum
 Lophotrichous – tuft of flagella at one pole
 Amphitrichous – two tufts at two poles
 Peritrichous – flagella surround whole cell

16. PILI
 Hollow, non-helical, filamentous appendages
 Smaller than flagella
 Not involved in motility
 Present in gram negative bacteria
 Made of protein “pilin”
 Involved in mating
• Special process called conjugation
• Help transfer genetic material
 Help in attachment with cell / surfaces

17. CELL ENVELOPE
 Extra covers outside membrane
 Diverse surface
• Capsule
• Slime
• Cell wall

18. CAPSULE
 Some bacteria have capsule
 Made up of
• Repeating polysaccharides
• Protein
• or both
 Tightly bound to cell
 Thick, gummy
 Colonies appear sticky

19. SLIME
 Loose, soluble shield
 Made of macromolecules
 Helps in pathogenicity
 Protects from phagocytosis

20. CELL WALL
 Below capsule and slime
 External to plasma membrane
 Rigid structure
 Determines shape of cell
 Protects from osmotic lysis
 Made of peptidoglycan
• Amount is variable
• Long glycan chains
• Cross-linked with peptide chains

21. CELL WALL
 Also contain
• Sugar, teichoic acid, lipoproteins and lipopolysaccharides
• Linked to peptidoglycan
 Staining technique
• Developed by Hans Christian Gram
• Two types of bacteria
 Gram positive
• Stained purple
• Retain primary dye (crystal violet)
 Gram negative
• Stained pink
• Retain secondary dye (safranin)

22. CELL WALL
Gram Positive Gram Negative
Number of layers 1 2
Chemical composition Peptidoglycan (50% of
dry weight in some)
Teichoic acid
Lipoteichoic acid
Lipids 1-4%
Peptidoglycan (10% of
dry weight in some)
Lipopolysaccharides
Lipoproteins
Lipids 11-12%
Overall thickness 20-80nm 8-11nm
Outer membrane No present Present
Periplasmic space Present in some Present in all
Permeability More permeable Less permeable
Staining Purple Pink
Retain dye Crystal violet Safranin

23. CELL WALL
 Some bacteria have different cell wall
• Neither gram negative nor gram positive
 Cell wall of archeobacteria
• Very different from eubacteria
• No peptidoglycan
• Made of protein, glycoprotein, polysaccharides
 Absent in Mycoplasma

24. CELL MEMBRANE
 Present below cell wall
 Thin, flexible structure
 Completely surrounds cytoplasm
 Delicate – any damage can kill cell
 Differs from eukaryotic membrane
• No sterols (like cholersterol)
 Main function is regulation of transport
• Proteins, nutrients, sugars, electrons etc.
 Enzymes for respiration

25. CYTOPLASMIC MATRIX
 Present between membrane and nucleoid
 No membrane bound organelles
 No cytoskeleton (microtubules etc)
 Gel like consistency
 Small molecules move freely
 Plasma membrane + cytoplasm = protoplast
 Contains
• Chromatin, ribosomes, mesosomes, granules etc.

26. NUCLEOID
 No nuclear membrane
 No discrete chromosomes
 DNA is present near center
• Specific region of cytoplasm
• Single circular chromosome
• Double stranded DNA
• Very long, tightly folded
• Dense area called nucleoid
 Only single chromosome – haploid
 Chromosome of E. coli is about 14,000μm
 Can be visualized by Feulgen stain

27. PLASMID
 Additional molecules of DNA
 Small, circular, double stranded DNA
 Self replicating
 Not essential for growth & metabolism
 Genes for emergency situation
• Antibiotic resistance
• Heavy metal resistance
 Important “vectors” in genetic engineering

28. RIBOSOMES
 RNA + Protein
 Some attached to plasma membrane
 Some dispersed in cytoplasm
 Smaller than eukaryotic ribosomes
• 50S + 30S = 70S
 Protein factories

29. MESOSOMES
 Invaginations of Plasma membrane
• Formed like vesicles, tubules, or lamellae
 Help in DNA replication, cell division
 Some are involved in export of enzymes
 Some contain respiratory enzymes

30. GRANULES AND
STORAGE BODIES
 Bacteria live in harsh environments
• Nutrients are in short supply
 Store nutrients whenever possible
• Glycogen, Sulphur, fats, phosphates
 Wastes are stored till disposal
• Alcohol, lactic acid, acetic acid

31. SPORES
 Produced by some species
 Two types
• Exospores – produced outside cell
• Endospores – produced inside cell
 Metabolically dormant bodies
 Produced when death is imminent
 Resistant to adverse conditions
• E.g. light, high temperature, desiccation, pH, chemicals
 Can germinate in favorable conditions
• Form new vegetative cell

32. CYSTS
 Also metabolically dormant
 Thick walled, desiccation resistant
 Develop during differentiation of vegetative cells
 Can germinate under suitable conditions
 Are not heat resistant

33. NUTRITION IN BACTERIA

34. NUTRITION IN BACTERIA
 Require energy like other organisms
• For growth, maintenance, reproduction
 Two main categories
• Heterotrophs
• Autotrophs
 Further divided into sub-categories
Heterotrophs
Saprotrophic
Parasitic
Autotrophs
Photosynthetic
Chemosynthetic

35. HETEROTROPHIC BACTERIA
 Cannot synthesize their own food
 Depend on others for nutrition
 Two types
 Saprotrophs
• Nutrition from dead organic matter
• From Humus (partially decayed matter) in soil
• Enzyme systems for breakdown
• Absorbs simple substance
 Parasites
• Obtain nutrition from host, cause disease

36. AUTOTROPHIC BACTERIA
 Can synthesize organic compounds
• From simple inorganic substances
 Photosynthetic autotrophs
• Have chlorophyll for photosynthesis
• Differs from green plants
• Not present within chloroplasts
• Dispersed in cytoplasm
• Utilize H2S instead of H2O, release S
 Chemosynthetic autotrophs
• Oxidize inorganic substances
• Like ammonia, nitrate, nitrite, Sulphur, ferrous ions
• Trap released energy for own reactions

37. RESPIRATION IN BACTERIA

38. RESPIRATION IN BACTERIA
 Breakdown of food to release energy
 Aerobic bacteria
• Cannot grow without oxygen
• E.g. Pseudomonas
 Anaerobic bacteria
• Can grow in absence of oxygen
• E.g. Spirochete
 Facultative bacteria
• Can grow in presence and absence of oxygen
• E.g. E. coli
 Microaerophilic
• Require low amount of oxygen
• E.g. Campylobacter

39. GROWTH AND REPRODUCTION

40. BACTERIAL GROWTH
 Increase in number of cells
 Binary fission
• Asexual reproduction
• Bacterium grows in size
• Chromosome duplicates
• Plasma membrane pinches inwards
• Cell separated into two
 Repeated after fix time
• If conditions are favorable
• Increase in population
 Generation time
• Interval from one division till next

41. BACTERIAL GROWTH CURVE
 A graph of population growth with time
• Four distinct phases
 Lag phase
• No increase in number
• Bacteria prepare for division
 Log phase
• Very rapid growth
• Divide at exponential rate
 Stationary phase
• Reproduction rate = death rate
 Decline phase
• Death rate more than reproduction

42. SEXUAL REPRODUCTION
 Traditional sexual reproduction is absent
 Special type of genetic mixing
 Transfer of genetic material
 From donor to recipient
 Through sex pili
 Called conjugation
 Produces new genetic combinations
 Help in survival

43. IMPORTANCE OF BACTERIA

44. ECOLOGICAL IMPORTANCE
 Very important
 Adaptable in different environments
 Found everywhere
 Decompose organic matter
 Recycle nutrients
• C, N, S, P
, O

45. ECONOMIC IMPORTANCE
 Used in industries
 Preparation of food
• yogurt, vinegar, alcohol
 Production of drugs
• Antibiotics, vaccines
 Biotechnology
• Production of proteins etc.
 Also spoil food and vegetables
 Plant pathogens destroy crops

46. MEDICAL IMPORTANCE
 Pathogens in humans
• 200 species cause disease
 Some are part of natural flora
• Live in and on body

47. CONTROL OF BACTERIA

48. CONTROL OF BACTERIA
 Essential in certain conditions
• Home, industry, medical fields
 Prevention and treatment of disease
 Prevention of spoilage of food
 Various methods of control
• Physical methods
• Chemical methods

49. PHYSICAL CONTROL
 Sterilization
• Use of physical agents
• Destruction of all life forms
 Dry heat
• Causes oxidation of chemical components
• kills all bacteria
 Moist heat
• Heat with steam
• Coagulation of proteins
• Kills all bacteria

50. PHYSICAL CONTROL
 Electromagnetic radiation
• UV radiation (<300 nm)
• Used in operation theatres, laboratories
• Gamma radiation (<100pm)
• for canned foods
 Filtration
• For heat sensitive substances
• proteins, drugs etc.

51. CHEMICAL CONTROL
 Chemical agents for bacterial control
 Antiseptics
• Used on living tissue
• Stop bacterial growth
• Not complete sterilization
• E.g. ethanol / spirit
 Disinfectants
• Used on non-living surfaces
• Harsh chemicals
• Halogens, phenols, H2O2
• Potassium permanganate,
• alcohols, formaldehyde

52. CHEMICAL CONTROL
 Chemotherapeutic agents
• Chemicals that are used inside body
• Work with immune system, Stop growth
• Sulfonamides, tetracycline, penicillin
 Microbicidal chemicals
• Kill bacteria immediately
 Microbistatic chemicals
• Stop the growth of bacteria
• Do not kill them
 Different mechanisms
• Preventing cell wall synthesis, damaging cell membranes,
inhibiting enzymes

53. IMMUNIZATION & VACCINATION

54. IMMUNIZATION & VACCINATION
 Immunization
• Boosting immune system
• T
o fight disease
 Vaccination
• Introduction of dead / weak bacteria
• T
o activate immune response
 Antisepsis
• Eliminating possibility of infection
 Chemotherapy & Public health measures
• Water purification,
• Sewage disposal,
• Food preservation

55. VACCINATION
 Edward Jenner 1796
• Developed vaccine against small pox
• By inoculation of cow-pox virus
• Two viruses are related
• Immune system considers them same
 Louis Pasteur (1880s)
• causative agent of chicken cholera
• Grew in pure culture
• Inoculation causes disease
• Used old cultures accidentally
• Developed vaccination
• Also vaccines for rabies

56. USE & MISUSE OF ANTIBIOTICS
 Chemotherapeutic chemical agents
• Help treat bacterial infections
• Synthesized by certain microbes
• Kill / stop other microbes
 Many synthesized in laboratory
 Complete knowledge is necessary
• Before using for treatment
 Overuse / misuse is common
• Results in antibiotic resistance
 Sometimes interfere with metabolism – side effects
• Streptomycin – auditory nerve damage / deafness
• Tetracycline – permanent discoloration of teeth
• Penicillin – allergy in some people

57. Blue-green algae
CYANOBACTERIA

58. CYANOBACTERIA
 Largest group of bacteria
 Most diverse group of photosynthetic bacteria
 Previously called blue-green algae
 Prokaryotes (not algae)
 Variable in size, shape, appearance
 Diameter 1 – 10 μm
 May be Unicellular / colonial / filaments
• Filaments are made of trichomes (chains of cells)
• Surrounded by mucilaginous sheath

59. CYANOBACTERIA
 Photosynthesis resembles plants
• Have chlorophyll a and PS II
• Oxygenic photosynthesis – release oxygen
• Accessory pigments – phycobilins
• Present on thylakoid membranes
• Also have electron transport chain
• Structures called phycobilosomes
 Phycocyanin pigment (blue)
• Predominant phycobilin
 CO2 fixation by Calvin cycle

60. CYANOBACTERIA
 Gram negative cell wall
 Use gas vesicles for swimming
• Some can glide
 Reserve food is glycogen
 Reproduce by binary fission
• Filaments by fragmentation
 Special structures
• Hormogonia, akinetes, heterocysts

61. ECONOMIC IMPORTANCE
 Reclamation of alkaline soil
 Heterocysts
• Fix atmospheric nitrogen
 Oxygenic photosynthesis
• Release oxygen
 Pollution indicators
• Oscillatoria and others
 Symbiotic relationships
• With protozoa, fungi
• With angiosperms (root nodules)
 Partners in lichens

62. ECONOMIC IMPORTANCE
 Super Blue-GreenAlgae
• Single celled cyanobacteria
• Produce food through photosynthesis
• Complete whole food
• 60% protein with essential amino acids
• Perfect balance
 Water blooms
• Unpleasant smell and taste
• Unfit for consumption
• Sometimes has toxins
• Can kill animals and livestock

63. NOSTOC
 Terrestrial and subterrestrial
 Common in alkaline soil
 On moist rocks and cliffs
 Forms jelly like mass
• Filaments are embedded in it
 Unbranched trichomes
• Appear beaded
• Cells are spherical
• Sometimes barrel shaped / cylindrical

64. NOSTOC
 Cells are similar in structure
 Heterocysts
• Slightly large, round, light yellowish
• Thick walled cell
• Carries out nitrogen fixation
 Hormogonia
• Trichome breaks near heterocyst
• Forms new colonies
• Called fragmentation

65. NOSTOC
 No sexual reproduction
 Reproduces asexually
• Through hormogonia formation
• Due to breakage of filaments
• Sometimes due to death of cells
• Or near heterocyst
 Akinete formation
• Thick walled, enlarged vegetative cells
• Accumulate food, become resting cells
• Germinate again in favorable cells