1. Introduction to Microbiology
Course name: Pharmaceutical Microbiology-I
Course Instructor: Nishat Jahan

2. Microbe, or microorganisms are minute living things that individually are usually too small to be seen with the unaided eye.
‘Micro’ means small or minute and ‘Bios’ is a Greek word that means life.
(Microbe = Micro+bios)
Micro-organisms: They are small organisms and are either microscopic or submicroscopic creatures. These populations are mainly unicellular but may be multicellular or even subcellular.
The group includes:
Bacteria
Fungi (Yeasts and molds)
Protozoa
Microscopic algae

3. Microbiology
Microbiology (from Greek mīkros, "small"; bios, "life"; and -logia) is the study of microscopic organisms. Microbiology includes the disciplines virology, mycology, parasitology, bacteriology, and so on.
It is the discipline which is concerned with the study of microorganisms and their interactions with the environment.
Pharmaceutical Microbiology mainly deals with the production of drugs by microbes, exploitation of microorganisms in the development of vaccine and production of recombinant protein to treat diseases which are untreatable by traditional methods.

4. Microbiology deals with
The form, structure, reproduction, physiology, metabolism and classification of the microorganisms.
The study of their distribution in nature.
Their relationship to each other and other living organisms.
Their effects on human beings and on other animals and plants.
Their abilities to make physical and chemical changes in our environment.
Their reaction to physical and chemical agents.

5. Classification of living organisms
Linnaeus (1753)
Plantae
Plant, Algae Fungi and Bacteria
Animalia
Protozoa and Higher Animals
Haeckel (1865)
Multicellular algae and Plants
Animals
Protista
Microorganisms including Bacteria
Whittaker (1969)
Multicellular algae and plants
Protozoa and single cell algae
Fungi
Moulds and yeasts
Monera
All bacteria (Prokaryotes)

7. Differences between Procaryotes &Eucaryotes
Features
Eukaryotic Cell
Prokaryotic Cell
Nucleus:
Present
Absent
Number of chromosomes:
More than one
One--but not true chromosome: Plasmids
Cell Type:
Usually multicellular
Usually unicellular (some cyanobacteria may be multicellular)
True Membrane bound Nucleus:
Example:
Animals and Plants
Bacteria and Archaea*
Lysosomes and peroxisomes:
Microtubules:
Absent or rare
Endoplasmic reticulum:
Mitochondria:
Cytoskeleton:
May be absent

8. Differeences cont.. Features Eukaryotic Cell Prokaryotic Cell
Ribosomes:
larger
smaller
Vesicles:
Present
Golgi apparatus:
Absent
Chloroplasts:
Present (in plants)
Absent; chlorophyll scattered in the cytoplasm
Flagella:
Microscopic in size; membrane bound; usually arranged as nine doublets surrounding two singlets
Submicroscopic in size, composed of only one fiber
Permeability of Nuclear Membrane:
Selective
not present
Plasma membrane with steriod:
Yes
Usually no
Cell wall:
Only in plant cells and fungi (chemically simpler)
Usually chemically complexed
Vacuoles:
Differeences cont..

9. Prokaryotes (from Old Greek pro- before + karyon nut or kernel, referring to the cell nucleus, + suffix -otos, pl. -otes; also spelled "procaryotes") are organisms without a cell nucleus (= karyon), or any other membrane-bound organelles. Most are unicellular, but some prokaryotes are multicellular).
Eukaryotes are organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. The most characteristic membrane bound structure is the nucleus. This feature gives them their name, (also spelled "eucaryote,") which comes from the Greek eu, meaning “true” and nucleus (= karyon) . Animals, plants, fungi, and protists are eukaryotes.

10. Bacteria: Size ranges from 0. 5µm-5. 0μm
Bacteria: Size ranges from 0.5µm-5.0μm. Prokaryotic; unicellular; simple internal structure; grow on artificial laboratory media; reproduction asexual, characteristically by simple cell division.
Example: Salmonella typhi, Bacillus cereus.
Viruses: Size ranges from 0.02μm-0.2µm. Do not grow in artificial laboratory media, reproduce only in living cells; obligate intracellular parasites.
Example: Myxovirus, Herpes simplex.
Fungi:
1. Yeasts: Size ranges from 5µm - 10μm. Eukaryotic; unicellular; grow on artificial laboratory media; reproduction by asexual cell division or sexual process.
 2. Molds: Size ranges from 2μm - 10µm; Eukaryotic; Multicellular; cultivated in artificial laboratory media; reproduction by asexual and sexual processes.
Example: Penicillium chrysogenum, Aspergillus niger.

11. Example: Entamoeba histolytica, Plasmodium vivax.
Protozoa: Size ranges from 2µm – 200µm; Eukaryotic; unicellular; some cultivated in laboratory; some are intracellular parasites; reproduction by asexual and sexual processes.
Example: Entamoeba histolytica, Plasmodium vivax.
Algae: Eukaryotic; unicellular and multicellular; most occur in aquatic environments; contain chlorophyll and are photosynthetic; reproduction by asexual and sexual processes.
Example: Spirulina, Anabena.
Cayanobacteria: These are prokaryotic but not regarded as true bacteria because of fundamental differences in how they form carbohydrate in photosynthesis. Cayanobacteria inhabit fresh water as well as marine environments and occurs as unicellular or filamentous organisms.

12. Microbiology as a field of biology
Microorganisms are exceptionally attractive models for life processes. They can be grown conventionally in the test tubes or flasks requiring less space and maintenance than larger plants and animals. They grow rapidly and reproduce at an usually high rate, some species of bacteria undergo almost 100 generations in a 24-hour period.
Metabolic processes of microorganisms follow patterns that occur among higher plants and animals. In fact, the mechanisms by which the organisms (or their cells) utilize energy are same throughout the biological world. Some microorganisms have the unique ability of using either radiant energy or chemical energy and thus are like both plants and animals.

13. Microbiology as a field of biology
Microorganisms are exceptionally attractive models for life processes. They can be grown conventionally in the test tubes or flasks requiring less space and maintenance than larger plants and animals. They grow rapidly and reproduce at an usually high rate, some species of bacteria undergo almost 100 generations in a 24-hour period.
Metabolic processes of microorganisms follow patterns that occur among higher plants and animals. In fact, the mechanisms by which the organisms (or their cells) utilize energy are same throughout the biological world. Some microorganisms have the unique ability of using either radiant energy or chemical energy and thus are like both plants and animals.

14. Furthermore, some microorganisms, the bacteria in particular are able to utilize a great variety of chemical substances as their energy source— ranging from simple inorganic substances to complex organic substances.
In microbiology we can study organisms in great detail and observe their life processes while they are actively metabolizing, growing, reproducing, aging, and dying. By modifying their environment we can alter metabolic activities, regulate, growth, and even change some details of their genetic pattern—all without destroying the organisms.

15. Microorganisms have a wider range of physiological and biochemical potentialities than-all other organisms combined. For example some bacteria are able to utilize atmospheric nitrogen for the synthesis of proteins and other complex organic nitrogenous compounds. Other species require inorganic or organic nitrogen compounds as the initial building blocks for their nitrogenous constituents.
Some microorganisms synthesize all their vitamins, while others need to be furnished vitamins. By reviewing the nutritional requirements of a large collection of microorganisms, it is possible to arrange them from those with the simplest to those with the most complex requirements.

16. Scope of Pharmaceutical Microbiology :
Different branch of Microbiology has different role in the advancement pharmaceutical sciences.
Basic Microbiology: Virology, Bacteriology, Mycology, Phycology and Protozoology
Environmental Microbiology: Including microbial ecology
Definition of aeromicrobiology, air-borne pathogens and allergens.
Medical Microbiology and Immunology: Human diseases and their causative agents. Role of various drugs in the treatment of those diseases. Antigen, antibody, structure and types of antibody, hapten, adjuvant, immune response.
Industrial Microbiology: Production of Antibiotics and other drugs by microbes (including therapeutic proteins) Modern pharmaceutical biotechnology encompasses gene cloning and recombinant DNA technology. Gene cloning comprises isolating a DNA-molecule segment that corresponds to a single gene and synthesizing ("copying") the segment.

17. Recombinant DNA technology enables modifying microorganisms, animals, and plants so that they yield medically useful substances
Genetic engineering is central to modern biotherapy’s backbone.
Pharmaceutical biotechnology involves using microorganisms, macroscopic organisms, or hybrids of tumor cells and leukocytes:
to create new pharmaceuticals;
to create safer and/or more effective versions of conventionally produced pharmaceuticals; and
to produce substances identical to conventionally made pharmaceuticals more cost-effectively than the latter pharmaceuticals are produced.

18. Basic microbiology:
It deals with
Morphological characteristics: The shape and size of cells and the chemical composition and function of their internal structures.
Physiological characteristics: For example, the specific nutritional requirement and physical conditions needed for growth and reproduction.
Biochemical activities: How the microbe breaks down nutrients to obtain energy and how it uses the energy to synthesize cellular components.
Genetic characteristics: Inheritance and variability of characteristics.
Disease causing potential: Present or absent, for human, other animals, plants. Animals, includes the study of host resistance to infection.
Ecological characteristics: The natural occurrence of microbes in the environment and their relationships with other organisms.
Classification: The taxonomic relationships among groups in the microbial kingdom.

19. Differences between Procaryots &Eucaryots
Features
Eukaryotic Cell
Prokaryotic Cell
Nucleus:
Present
Absent
Number of chromosomes:
More than one
One--but not true chromosome: Plasmids
Cell Type:
Usually multicellular
Usually unicellular (some cyanobacteria may be multicellular)
True Membrane bound Nucleus:
Example:
Animals and Plants
Bacteria and Archaea*
Lysosomes and peroxisomes:
Microtubules:
Absent or rare
Endoplasmic reticulum:
Mitochondria:
Cytoskeleton:
May be absent

20. Differeences cont.. Features Eukaryotic Cell Prokaryotic Cell
Ribosomes:
larger
smaller
Vesicles:
Present
Golgi apparatus:
Absent
Chloroplasts:
Present (in plants)
Absent; chlorophyll scattered in the cytoplasm
Flagella:
Microscopic in size; membrane bound; usually arranged as nine doublets surrounding two singlets
Submicroscopic in size, composed of only one fiber
Permeability of Nuclear Membrane:
Selective
not present
Plasma membrane with steriod:
Yes
Usually no
Cell wall:
Only in plant cells and fungi (chemically simpler)
Usually chemically complexed
Vacuoles:
Differeences cont..

21. The Archaea constitute a domain or kingdom of single-celled microorganisms. These microbes have no cell nucleus or any other membrane-bound organelles within their cells.
Major Fields of applied microbiology
Microbial Physiology-The study of biochemical functions of microbial cells. It includes the study of microbial growth,microbial metabolism and microbial cell structure.
Medical microbiology: Causative agents of diseases; diagnostic procedures; diagnostic procedures for identification of causative agents; preventive measures.
Pharmaceutical microbiology: The study of microorganisms that are related to the production of antibiotics, enzymes, vitamins, vaccines, and other pharmaceutical products and that cause pharmaceutical contamination and spoil.
Aquatic microbiology: Water purification; microbiological examination; biological degradation of waste; ecology. 
Agricultural microbiology: The study of agriculturally relevant microorganisms. This field can be further classified into the following:
Plant microbiology and Plant pathology: The study of the interactions between microorganisms and plants and plant pathogens.
Soil microbiology: The study of those microorganisms that are found in soil.

22. Aero microbiology: Contamination and spoilage; dissemination of diseases.
Industrial microbiology: Production of medicinal products such as antibiotics and vaccines; fermented beverages; industrial chemicals; production of proteins and hormones by genetically engineered microorganisms.
Food microbiology and Dairy microbiology: The study of microorganisms causing food spoilage and food borne illness. Using microorganisms to produce foods, for example by fermentation.
Exo-microbiology: Exploration for life in outer space.
Geochemical microbiology: Coal, mineral and gas formation; prospecting for deposits of coal, oil, and gas; recovery of minerals from low-grade ores. 
Environmental microbiology: The study of the function and diversity of microbes in their natural environments. This involves the characterization of key bacterial habitats such as the rhizosphere and phyllosphere, soil and groundwater ecosystems, open oceans or extreme environments (extremophiles). This field includes other branches of microbiology such as:
Microbial ecology, Microbially-mediated nutrient cycling, Microbial diversity& Bioremediation
Epidemiology: The study of the incidence, spread, and control of disease.

23. Application of Microbiology
Many microbes are responsible for numerous beneficial processes such as industrial fermentation(e.g alcohol, dairy products), antibiotic production, as vehicle for cloning in higher organism such as plant.
Microbes are used to produce biotechnologically important enzymes such as Taq polymerase, reporter genes for use in other genetic system
Bacteria can be used for the production of protein in industry.
Different biopolymers such as polyamides, polysaccharides are produced from micro organisms.
They are beneficial for biodegradation or bioremediation of domestic agricultural & industrial wastes.
Recently it has been proposed that they can be used in cancer therapy.

24. Task
Why microbiology is important for the food industry? Explain with few examples.

25. HISTORY OF MICROBIOLOGY
Pharmaceutical Microbiology-I
Course Instructor: Nishat Jahan

26. The First Observations
Subsequent investigations into the structure and functions of cells were based on this theory.
Hooke's discovery marked the beginning of the cell theory ‘the theory that all living things are composed of cells.’
Using his improved version of a compound microscope (one that uses two sets of lenses), Hooke was able to see individual cells.
In 1665 Robert Hooke reported to the world that life’s smallest structural units were ‘little boxes’ or ‘cells’.

27. Animalcules

28. The First Observations (contd)
Though Hooke's microscope was capable of showing large cells, he lacked the resolution that would have allowed him to see microbes clearly.
The Dutch merchant and amateur scientist Anton van Leeuwenhoek was probably the first actually to observe live microorganisms through the magnifying lenses of more than 400 microscopes he consturcted.

29. Anton van Leeuwenhoek's microscopic observations

30. Anton van Leeuwenhoek
His letters were read in the British Royal Society but its significance was not understood until Pasteur told that microorganisms are responsible for different diseases and processes.
Describing ‘‘animalcules’’ in rainwater, faces and material scraped from teeth….these drawing were identified as representations of bacteria and protozoa
He carefully recorded his observations in a series of letters to the British Royal Society.

31. Spontaneous Generation
In 1668, the Italian physician Francesco Redi a strong opponent of spontaneous generation, set out to demonstrate that maggots did not arise spontaneously from decaying meat.
They called this hypothetical process Spontaneous Generation.
Until the second half of the nineteenth century, many scientists and philosophers believed that some forms of life could arise spontaneously from nonliving matter.

32. Maggots- larvae of a fly

33. Spontaneous Generation Contd.
Redi filled two jars with decaying meat.
The first was left unsealed; the flies laid their eggs on the meat, and the eggs developed into larvae.
The second jar was sealed, and because the flies could not lay their eggs on the meat, No maggots appeared.

34. Spontaneous Generation (contd)
Still, Redi's antagonists were not convinced; they claimed that fresh air was needed for spontaneous generation.
So Redi set up a second experiment, in which he covered a jar with fine net instead of sealing it.
No larvae appeared. Maggots appeared only when flies were allowed to leave their eggs on the meat.

35. Spontaneous Generation (contd)
In 1745, when John Needham, an Englishman, found that even after he heated nutrient fluids (chicken broth and corn broth) before pouring them into covered flasks.
The cooled solutions were soon teeming with microorganisms.
Needham claimed that microbes developed spontaneously from the fluids.
Twenty years later, Lazzaro Spallanzani, an Italian scientist, suggested that microorganisms from the air probably had entered Needham's solutions after they were boiled.
Spallanzani showed that nutrient fluids heated after being sealed in a flask did not develop microbial growth.

36. Spontaneous Generation (contd)
Needham responded by claiming the "vital force" necessary for spontaneous generation had been destroyed by the heat and was kept out of the flasks by the seals.
Anton Laurent Lavoisier showed the importance of oxygen to life.
Spallanzani's observations were criticized on the grounds that there was not enough oxygen in the sealed flasks to support microbial life.

37. Theory of Biogenesis
In 1858, when the German scientist Rudolf Virchow challenged the case for spontaneous generation with the concept of biogenesis, the claim that
‘living cells can arise only from preexisting living cells’.
In 1961, French scientist Louis Pasteur demonstrated that
‘microorganisms are present in the air and can contaminate sterile solutions, but that air itself does not create microbes’.

38. LOUIS PASTEUR’S EXPERIMENT
He filled several short-necked flasks with beef broth and then boiled their contents.
Some were then left open and allowed to cool. In a few days, these flasks were found to be contaminated with microbes.
The other flasks, sealed after boiling, were free of microorganisms.
From these results, Pasteur reasoned that microbes in the air were the agents responsible for contaminating nonliving matter such as the broths in Needham's flasks.

39. LOUIS PASTEUR’S EXPERIMENT
The broth in the flasks did not decay and showed no signs of life, even after months.
The contents of this flask was then boiled and cooled.
Pasteur next placed broth in an open-ended, long necked flasks and bent the necks into S-shaped curves.

41. Why didn’t the microorganisms appear in the broth ?
Pasteur's unique design allowed air to pass into the flask, but the curved neck trapped any airborne microorganisms that might contaminate the broth.

42. Louis Pasteur Contd.
Pasteur showed that microorganisms can be present in non-living matter-on solids, in liquid and in the air.
He demonstrated that microorganisms can be destroyed by heat and methods can be devised to prevent the microorganisms to enter the nutrient environments.
Basis of “ASEPTIC TECHNIQUES”

43. ASEPTIC TECHNIQUES
Techniques that prevent contamination by unwanted microorganisms.
Standard procedures in laboratory and medical procedures.

44. The Golden Age of Microbiology
Period from to 1914
Rapid advances took place
- discoveries of agents of many diseases
- role of immunity in preventing and curing disease.
-techniques for performing microscopy and culturing microorganisms improved.
- development of vaccines

45. The Golden Age- Fermentation and Pasteurization
Pasteur found that microorganisms called yeasts convert the sugars to alcohol in the absence of air. This process, called fermentation is used to make wine and beer.
Yeast
Sugars Alcohol
in absence of air

46. The Golden Age- Fermentation and Pasteurization
Souring and spoilage are caused by different
microorganisms called bacteria.
In the presence of air, bacteria change the alcohol in the beverage into vinegar (acetic acid).
Bacteria
Alcohol Vinegar (Acetic acid)
in the presence of air

47. Fermentation and Pasteurization (contd)
Pasteur's solution to the spoilage problem to heat the beer and wine just enough to kill most of the bacteria that caused the spoilage.
The process, called pasteurization, is now commonly used to reduce spoilage and kill potentially harmful bacteria in milk as well as in some alcoholic drinks.
This was the major step towards establishing the relationship between disease and microbes.

48. The Germ Theory of Disease
Before the time of Pasteur, effective treatments for many diseases were discovered by trial and error, but the causes of the diseases were unknown.
The realization that yeasts play a crucial role in fermentation
was the first link between the activity of a microorganism and physical and chemical changes in organic materials.
This discovery alerted scientists to the possibility that microorganisms might have similar relationships with plants and animals—specifically, that
microorganisms might cause disease.
This idea was known as the germ theory of disease.

49. The Germ Theory of Disease
In 1865, Pasteur was called upon to help fight silkworm disease, which was ruining the silk industry throughout Europe.
In 1835, Agostino Bassi, an amateur microscopist, had proved that another silkworm disease was caused by a fungus.
Using data provided by Bassi, Pasteur found that the more recent infection was caused by a protozoan, and he developed a method for recognizing afflicted silkworm moths.

50. The Germ Theory of Disease
In the 1860s, Joseph Lister, an English surgeon, applied the germ theory to medical procedures. Lister was aware that in the
1840s, the Hungarian physician Ignaz Semmelweis had demonstrated
that physicians,. Lister had who at the time did not disinfect their hands, routinely transmitted infections (puerperal, or childbirth,
fever) from one obstetrical patient to another
also heard of Pasteur’s work connecting microbes to animal diseases.

51. Disinfectants were not used at the time, but Lister knew that phenol (carbolic acid) kills bacteria, so he began treating surgical wounds with a phenol solution.
The practice so reduced the incidence of infections and deaths that other surgeons quickly adopted it.

52. The Germ Theory of Disease
The first proof that bacteria actually cause disease came from a German physician, Robert Koch in 1876.
Koch discovered rod -shaped bacteria now known as Bacillus anthracis in the blood of cattle that had died of anthrax.
He cultured the bacteria on nutrients
and then injected samples of the culture into healthy animals.
When these animals became sick and died, Koch isolated the bacteria in their blood
and compared them with the bacteria originally isolated.
He found that the two sets of blood cultures contained the same bacteria.

53. The Germ Theory of Disease
Koch established a sequence of experimental steps for directly relating a specific microbe to a specific disease. These steps are known today as Koch's postulates.
Koch’s postulates provides a framework for the study of etiology of any infectious disease.

55. Vaccination
Injection of a killed microbe in order to stimulate the immune system against the microbe, thereby preventing disease.

56. How Vaccination came about?
Edward Jenner, a young British physician, embarked on an experiment to find a way to protect people from smallpox.
When a young milkmaid informed Jenner that she couldn't get smallpox because she already had been sick from cowpox-a much milder disease- he decided to put the girl's story to the test.
First Jenner collected scrapings from cowpox blisters.
Then he inoculated a healthy 8-year-old volunteer with the cowpox material by scratching the person's arm with a pox-contaminated needle.

57. How Vaccination came about?
The scratch turned into a raised bump. In a few days, the volunteer became mildly sick but recovered and never again contracted either cowpox or smallpox.
The process was called vaccination from the Latin word vacca meaning cow.
Pasteur gave it this name in honor of Jenner's work. The protection from disease provided by vaccination (or by recovery from the disease itself) is called immunity.

58. How Vaccination came about?
Years after Jenner's experiment, in about 1880, Pasteur discovered why vaccinations work.
He found that the bacterium that causes fowl cholera lost its ability to cause disease (lost its
virulence or became avirulent) after it was grown in the laboratory for long periods.
However, it- and other microorganisms with decreased virulence-was able to induce immunity against subsequent infections by its virulent counterparts.
The discovery of this phenomenon provided a clue to Jenner's successful experiment with cowpox.

59. How Vaccination came about?
Both cowpox and smallpox are caused by viruses.
Even though cowpox virus is not a laboratory-produced derivative of smallpox virus, it is so closely related to the smallpox virus that it can induce immunity to both viruses.
Pasteur used the term vaccine for cultures of avirulent microorganisms used for preventive inoculation.

60. Chemotherapy
Microbiologists focused on destroying pathogenic microorganisms without killing infected organisms or humans.
Treatment of disease by using chemical substances is called chemotherapy.
Chemicals produced naturally by bacteria and fungi to act against other microorganisms are called antibiotics.
Chemotherapeutic agents prepared from chemicals in the laboratory are called synthetic drugs.

61. The First Synthetic Drugs
Paul Ehrlich speculated a ‘magic bullet’ that can destroy the pathogen but not the infected host
He introduced an arsenic-containing chemical called salvarsan to treat syphilis (1910) .

62. Discovery of Antibiotics
Alexander Fleming, a Scottish physician and bacteriologist, almost tossed out some culture plates that had been contaminated by mold.
Fortunately, he took a second look at the curious pattern of growth on the contaminated plates.
Around the mold was a clear area where bacterial growth had been inhibited

63. Discovery of Antibiotics
Fleming was looking at a mold that could inhibit the growth of a bacterium.
The mold was later identified as Penicillium notatum, later renamed Penicillium chrysogenum.
In 1928 Fleming named the mold's active inhibitor penicillin.
Thus, penicillin is an antibiotic produced by a fungus.

65. Why drug resistance occurs?
Drug resistance results from genetic changes in microbes that enables them to tolerate a certain amount of an antibiotic that would normally inhibit them.
These changes might include
the production by microbes of chemicals (enzymes) that inactivate antibiotics,
changes in the surface of a microbe that prevent an antibiotic from attaching to it,
and prevention of an antibiotic from entering the microbe.

66. Phagocytosis
Elie Metchnikoff, a Russian, described how certain leukocytes could ingest disease producing bacteria in the body
he called these special defenders against infection phagocytes (“eating cells”) and the process Phagocytosis. Metchnikoff formulated the theory that the phagocytes were the body’s first and most important line of defense against infection.

67. A Chronology of events important in the history of microbiology
Era
Investigator
Contribution
Girolamo Fracastoro
Theory that invisible lining seeds caused disease
Francesco Redi
Performed experiments to disprove spontaneous generation
Antony van Leeuwenhoek
First to observe and accurately record and report microorganisms
John Needham
Performed experiments, result supported concept of spontaneous generation
Lazaro Spallanzani
Did experiments, results disproved spontaneous generation
Edward Jenner
Discovered vaccination for small pox using cowpox vaccine

68.
Theodor Schwann
Performed experiments, result disproved spontaneous generation
Frans Schultze
Performed experiments, results disproved spontaneous generation
Oliver Windel Holmes
Stressed contagiousness of puerperal fever; host agent was carried from one other to another by doctors.
Ignaz Philipp Semmelweis
Introduced use of antiseptic
Louis Pasteur
Established germ theory of fermentation and gem theory of diseases, developed immunization techniques.
Joseph Lister
Developed aseptic technique, isolated bacteria in pure culture

69. Developed fractional sterilization to kill spores (Tyndallization)
Era
Investigator
Contribution
John Tyndall
Developed fractional sterilization to kill spores (Tyndallization)
Fanny Hesse
Suggested use of agar as solidifying material for microbiological media
Robert Koch
Developed pure culture technique and Koch’s Postulates; discovered causative agents of anthrax and tuberculosis.
Paul Erlich
Developed modern concept of chemotherapy and chemotherapeutic agents
Elie Methchnikoff
Discovered Phagocytosis
Hans Christian Gram
Developed important procedure for differential staining of bacteria, the Gram stain

70. Introduced complement-fixation test for syphilis
Era
Investigator
Contribution
August von Wassermann
Introduced complement-fixation test for syphilis
Martinus
Beijerinck
Willem
Utilized principles of enrichment cultures; confirmed finding of first virus.

71. Classification of living organisms
Linnaeus (1753)
Plantae
Plant, Algae Fungi and Bacteria
Animalia
Protozoa and Higher Animals
Haeckel (1865)
Multicellular algae and Plants
Animals
Protista
Microorganisms including Bacteria
Whittaker (1969)
Multicellular algae and plants
Protozoa and single cell algae
Fungi
Moulds and yeasts
Monera
All bacteria (Prokaryotes)

72. Classification system
The way we have classified organisms has changed greatly over the centuries.
From the time of Aristotle, living organisms were categorized in just two ways:
as either plants or animals.
In 1735 Carolus Linnaeus introduced a formal system of classification with two kingdoms—
Plantae and Animalia.

73. Classification system
As the biological sciences developed, a natural classification system—
one that groups organisms based on ancestral relationships
and allows us to see the order in life—was sought.
In the 1800s, Carl von Nägeli proposed that bacteria and fungi be placed in the plant kingdom
while Ernst Haeckel proposed
the Kingdom Protista, to include bacteria, protozoa, algae, and fungi.

74. In 1969, Robert H. Whittaker founded the five-kingdom system in which prokaryotes were placed in the Kingdom Prokaryotae, or Monera,
and eukaryotes comprised the other four kingdoms.

75. Five-Kingdom Classification

76. The Three domains
The discovery of three cell types was based on the observations
that ribosomes are not the same in all cells.
Ribosomes are present in all cells. Comparing the sequences of nucleotides in ribosomal RNA from different kinds of cells shows that there are three distinctly different cell groups:
the eukaryotes and two different types of prokaryotes—the bacteria and the archaea.

77. The Three Domains
In 1978, Carl R. Woese proposed elevating the three cell types to a level above kingdom, called domain.
In this widely accepted scheme, animals, plants, and fungi are kingdoms in the Domain Eukarya.
The Domain Bacteria includes all of the pathogenic prokaryotes as well as many of the nonpathogenic prokaryotes found in soil and water.
The Domain Archaea includes prokaryotes that do not have peptidoglycan in their cell walls.

78. The Three Domains