introduction of microbiology saravanan

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Koch’s postulates :

Koch’s postulates The microbe must be found in the body in all cases of the disease It must be isolated from a case and grown in a series of pure culture in vitro It reproduce the disease on the inoculation of a late pure culture into a susceptible animal The microbe must be isolated again into pure culture from such experimentally caused infection. Microbiology R.SARAVANAN. DEPARTMENT OF BIOTECHNOLOGY QIS COLLEGE OF PHARMACY, ONGOLE .

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OBJECTIVES Define microbiology. Origen of microbiology. Various types of microorganism. Scope and importance of microbiology Discovery of spontaneous generation theory Important contributions of various scientist to microbiology Antony van Leeuwenhoek , Pasteur , Koch , Joseph lister . Redi , Needham, Jenner, Fleming.


MICROBIOLOGY Microbiology is the branch of biology that studies microorganism and their effects on humans, which are unicellular or multi-cellular organism. This includes eukaryotes and prokaryotes. Microbiology is the scientific study of very small living organism that are too small not to be seen with the naked eye. Usually it requires a magnification tool to visualize. Ex. Microscope.

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In broad sense microbiology is a bioscience for the study of the evolution, Classification , morphology , physiology, genetics, ecology of microbes under certain definite conditions. Microorganisms are everywhere; almost every natural surface is colonized by microbes, from body to ocean. Some microorganisms can live hot springs, and others in frozen sea ice . MICROBIOLOGY

Groups of Microorganisms:

Groups of Microorganisms Bacteria archeans Fungi (yeasts and molds ) algae Helminths protozoans Viruses ( acellular organism)


Procaryotes Procaryotes: relative simple morphology and lack true membrane delimited nucleus


Eucaryotes Eucaryotes: morphologically complex with a true membrane enclosed nucleus


Prokaryotes Peptidoglycan cell walls Binary fission For energy, use organic chemicals, inorganic chemicals, or photosynthesis Bacteria Figure 1.1a

Rob-Shaped Bacteria:

Rob-Shaped Bacteria

Spherical Bacteria:

Spherical Bacteria


Prokaryotic Lack peptidoglycan Live in extreme environments Include: Methanogens Extreme halophiles Extreme thermophiles Archaea : Halobacteria not from book


Eukaryotes Chitin cell walls Use organic chemicals for energy Molds and mushrooms are multicellular consisting of masses of mycelia , which are composed of filaments called hyphae Yeasts are unicellular Fungi Figure 1.1b


Eukaryotes Cellulose cell walls Use photosynthesis for energy (primary producers) Produce molecular oxygen and organic compounds Metabolically diverse Algae Figure 1.1d


19 HELMINTHS Tapeworm Ascaris round worm


Eukaryotes Absorb or ingest organic chemicals May be motile via pseudopods , cilia, or flagella Most free some parasites Protozoa Figure 1.1c


Acellular Consist of DNA or RNA core Core is surrounded by a protein coat Coat may be enclosed in a lipid envelope Viruses are replicated only when they are in a living host cell Viruses Figure 1.1e Bacteriophage

Viruses :

HIV Avian Flu Viruses

Multicellular Animal Parasites:

Eukaryote Multicellular animals Parasitic flatworms and round worms are called helminths. Microscopic stages in life cycles. Multicellular Animal Parasites Figure fluke


SCOPE AND IMPORTANCE OF MICROBIOLOGY Microbial physiology The study of how the microbial cell functions biochemically. Includes the study of microbial growth, microbial metabolism and microbial cell structure Microbial genetics The study of how genes are organized and regulated in microbes in relation to their cellular functions. Closely related to the field of molecular biology


Medical microbiology The study of the role of microbes in human illness. Includes the study of microbial pathogenesis and epidemiology and is related to the study of disease pathology and immunology Veterinary microbiology The study of the role in microbes in veterinary medicine or animal taxonomy. FIELDS OF STUDY….. SCOPE AND IMPORTANCE OF MICROBIOLOGY

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Environmental microbiology The study of the function and diversity of microbes in their natural environments. Includes the study of microbial ecology, microbe-mediated nutrient cycling, geomicrobiology , microbial diversity and bioremediation. Characterization of key bacterial habitats such as the rhizosphere and phyllosphere . SCOPE AND IMPORTANCE OF MICROBIOLOGY


Evolutionary microbiology The study of the evolution of microbes. Includes the study of bacterial systematics and taxonomy. Industrial microbiology The exploitation of microbes for use in industrial processes. Examples include industrial fermentation and wastewater treatment. Closely linked to the biotechnology industry. This field also includes brewing, an important application of microbiology. FIELDS OF STUDY….. SCOPE AND IMPORTANCE OF MICROBIOLOGY


Aeromicrobiology The study of airborne microorganisms. Food Microbiology The study of microorganisms causing food spoilage. Pharmaceutical microbiology the study of microorganisms causing pharmaceutical contamination and spoilage. SCOPE AND IMPORTANCE OF MICROBIOLOGY


Parasitology The study of parasites, their hosts, and the relationship between them. The focus of study is on relationship and NOT the organisms. SCOPE AND IMPORTANCE OF MICROBIOLOGY

Spontaneous generation Vs Biogenesis:

The hypothesis that living organisms arise from nonliving matter is called spontaneous generation. According to spontaneous generation, a “vital force’ forms life. The Alternative hypothesis, that the living organisms arise from preexisting life, is called biogenesis. Spontaneous generation Vs Biogenesis

Brief History Microbiology:

Anton van Leeuwenhoek (1670s) = microscopy Edward Jenner (1796) = vaccination against smallpox Ignaz Semmelweis (1840s) = hand washing before surgery Louis Pasteur (1860s) = repudiation spontaneous generation Joseph Lister (1860) = father aseptic surgery Robert Koch (1870s) = Koch’s postulates Dmitri Iwanowski (1990s) = Inference of viruses Alexander Fleming (1920s) = Penicillin Stephen T. Abedon (2000s) = not one heck of a lot…. Brief History Microbiology

Spontaneous Generation:

Spontaneous Generation As for as human beings were concerned, greek explanation that god Gaea was create the people from stones Aristotle (384-322 B.C.) says animals might originate spontaneously from soil, plant or other unlike animals. About 40 B.C., Virgil (70-19 B.C.)gave directions for the artificial propagation of bees from meat.

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Redi's Problem Where do maggots come from? Do they form by Spontaneous Generation Hypothesis: Maggots come from flies. Redi put meat into three separate jars. Jar 1 was left open Jar 2 was covered with netting Jar 3 was sealed from the outside Francesco redi opposed the spontaneous generation

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Francesco Redi (1626-1678)

Francesco Redi (1626-1678):

Francesco Redi (1626-1678) Left open Maggots developed Flies were observed laying eggs on the meat in the open jar Covered with netting Maggots appeared on the netting Flies were observed laying eggs on the netting Sealed No maggots developed

John Needham (1713-1781):

John Needham (1713-1781) proposed that a biogenesis occurred due to the random "clumping of organic molecules“.

Lazzaro spallanzani (1729-1799):

Lazzaro spallanzani opposed the Needham’s spontaneous generation theory. He Boiled “broth” in glass containers and melted, then glass was closed . Nothing will Grew after incubation. So the above technique was Criticized and Needham insisted that air is essential for the growth of microorganism Lazzaro spallanzani (1729-1799)


THEODOR SCHWANN, FRANZ SCHULZE, RUDOLPH VIRCHOW'S (1861) publication of his findings that all cells are derived from pre-existing cells (no spontaneous generation). THEODOR SCHWANN, FRANZ SCHULZE, "treating" the air that entered unsealed flasks of boiled infusions (methods ranged from sucking air through acid baths, through red-hot glass tubing). These experiments also demonstrate that spontaneous generation does not occur. Critics insist, again, that the air has been "damaged" by these treatments.

H. Schroder and T. von Dusch (1850):

H. Schroder and T. von Dusch (1850) H. Schroder and T. von Dusch (~ 1850) : carried out a more logical and convincing experimental design by passing air via cotton fibers so as to prevent the bacterial growth ; and thus, it ultimately initiated and gave rise to a basic technique of ‘plugging’ bacterial culture tubes with ‘cotton plugs’ (stoppers), which technique being used still as to date (Fig. : 1.B). Felix Archimede Pouchet (1800–1872) : revived once again the concept and ideology of spontaneous generation via a published comprehensive and extensive research article thereby proving its occurrence.

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Louis Pasteur (1822-1895) Pasteur prepared S-shaped flask The nutrient solution were heated in the flask, and air is untreated and unfiltered- the air can pass in and out. He devised the ingenious curved necked flasks that prevented contaminated air from reaching boiled beef broth – the broth remained uncontaminated even though exposed to the air. The germs grow only in the gooseneck not in solution.

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He explained the germs were float in the air, because of this only microbes wwre grown in the gooseneck of the flask. Finally, he proved that microorganisms do not arise by spontaneous generation. Louis Pasteur (1822-1895)

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He conducted experiments in a specially designed box. Finally, he proved that dust only carried the germs in air. If no dust in the air , the sterile broth remained free of microbial growth for indefinite periods. John Tyndall (1820 – 1893)

Tyndall’s chamber :

Tyndall’s chamber

John Tyndall (1820 – 1893):

John Tyndall (1820 – 1893) In 1876 discovered that there were two different types of bacteria. a) Heat sensitive or heat labile forms (vegetative cells) easily destroyed by boiling b) Heat resistant types known as an endospore Tyndall demonstrated that alternate process of heating & cooling if repeated five times, can kill all the endospores. This is known as Sterilization process or Tyndallization

The Golden Age of Microbiology:

The Golden Age of Microbiology 1857-1914 Beginning with Pasteur’s work, discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs

The Germ Theory of Disease:

1835: Agostino Bassi showed a silkworm disease was caused by a fungus. 1865: Pasteur believed that another silkworm disease was caused by a protozoan. 1840s: Ignaz Semmelwise advocated hand washing to prevent transmission of puerperal fever from one OB patient to another. The Germ Theory of Disease

The Germ Theory of Disease:

1860s: Joseph Lister used a chemical disinfectant to prevent surgical wound infections after looking at Pasteur’s work showing microbes are in the air, can spoil food, and cause animal diseases. 1876: Robert Koch provided proof that a bacterium causes anthrax and provided the experimental steps, Koch’s postulates, used to prove that a specific microbe causes a specific disease. The Germ Theory of Disease

Germ Theory of Disease:

Germ Theory of Disease A theory that proposes that microorganisms are the cause of many diseases. Contributors: Girolamo Fracastoro Agostino Bassi John Snow Louis Pasteur Robert Koch

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Hooke’s Microscope:

Hooke’s Microscope

First Observations:

First Observations Robert Hooke’s (1635-1703) reputation in the history of biology largely rests on his book Micrographia , published in 1665. Hooke devised the compound microscope and illumination system

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In 1665, Robert Hooke used one of the first microscopes to look more closely at the living world. A slice of cork caught his eye. Looking at thousands of tiny chambers, Hooke termed these structures cells because they reminded him of the rooms in a monastery.

Robert Hooke:

Robert Hooke

Antoni Van Leeuwenhoek (1632-1723):

Antoni Van Leeuwenhoek –1673 - probably the first person to observe living cells with a simple microscope, amateur scientist, ground his own lenses and described what we know today as bacteria – rod shaped , spiral shaped , etc. “animalcules” Antoni Van Leeuwenhoek ( 1632-1723)

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Antoni Van Leeuwenhoek ( 1632-1723)

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Microscope Specimen

Carl Zeiss and Ernst Abbe:

Carl Zeiss and Ernst Abbe

Ernst Ruska:

Ernst Ruska

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Electron Microscope – Expense and size prohibit use in the Dr.’s Offices

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Eyepiece Coarse focus  Fine focus   Objectives  Stage  Light Source Arm  Base  Projection Microscope

Compound light microscopy:

Compound light microscopy Basic parts Eyepieces (ocular lens) Base Condenser Iris diaphragm Objective lens Body tube Mechanical stage Adjustment knobs

Louis Pasteur:

Louis Pasteur * Pasteur – French scientist that dealt the death blow to the spontaneous generation theory. *Developed the germ theory in 1798 *Also developed vaccine against anthrax. * Pasteurization technique *Developed the germ theory of disease “Father of bacteriology and immunology” Louis Pasteur (1822-1895)

Microbiology – Chapter 1:

Microbiology – Chapter 1 1. He developed process we call Pasteuriztion – he heated wine to kill contaminating microbes – cured sick wine (today we heat treatment to kill pathogens in milk also) 2. He proved that fermentation was caused by a microbe – yeast 3. He developed vaccines for rabies and anthrax. Vaccines led to immunity to diseases that routinely killed many people, used to help people long before they understood how they even worked (science of Immunology) 4. He began the revolution in science that led to the Golden Age of Microbiology (from 1857-1914) Louis Pasteur (1822-1895)

Louis Pasteur in his lab:

Louis Pasteur in his lab


Pasteur showed that microbes are responsible for fermentation. Fermentation is the conversation of sugar to alcohol to make beer and wine. Microbial growth is also responsible for spoilage of food. Bacteria that use alcohol and produce acetic acid spoil wine by turning it to vinegar (acetic acid). Pasteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine. This application of a high heat for a short time is called pasteurization. Fermentation


Pasteurization The process of heating liquids for the purpose of destroying viruses and harmful organisms such as bacteria, protozoa, molds, and yeasts. Does not intend to kill all micro-organisms (pathogenic) in the food. Instead, aims to achieve a "log reduction" in the number of viable organisms, reducing their number so they are unlikely to cause disease (assuming the pasteurized product is refrigerated and consumed before its expiration date).

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Robert Koch - Developed Koch’s postulates – important technique for determining the actual microbial cause agent of a disease – more later, German, contemporary of Pasteur, several very important contributions He discovered the tuberculosis bug ( tubercle bacillus, Mycobacterium tuberculosis) 2. He discovered the cause of anthrax (Bacillus anthracis ) – from blood of dead cattle, cultured bacteria in pure culture, injected bacteria in live cattle and they died, then again cultured the bacteria in pure culture. This led to the establishment of a procedure for determining microbial cause of disease. Robert Koch (1843-1910 )

Although the microscope was invented in the 1600’s, it took 200 years for scientists to discover its use in isolating and identifying specific microbes for a particular disease.:

Although the microscope was invented in the 1600’s, it took 200 years for scientists to discover its use in isolating and identifying specific microbes for a particular disease. Robert Koch ( 1843-1910 )

Credited with demonstrating the first direct link between a single microbe and a single disease – Tuberculosis. :

Credited with demonstrating the first direct link between a single microbe and a single disease – Tuberculosis. 1 in 7 People Died from TB Robert Koch ( 1843-1910 )

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The organisms should be present in diseased individuals but not in healthy individuals The organisms must be cultured away from the plant or animal body Such a culture, when inoculated into susceptible animals, should initiate the characteristic disease symptoms The organisms should be re-isolated from these experimental animals and cultured again in the laboratory, after which it should still be the same as the original organism. Koch’s Postulates

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Koch’s postulates Koch’s Postulates

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Koch’s postulates Isolation of Microorganisms During Koch’s studies, it became necessary to isolate suspected bacterial pathogens . He cultured bacteria on the sterile surfaces of cut, boiled potatoes  Not satisfactory. Regular liquid medium solidified by adding gelatin  gelatin melted @ T>28 °C. Fannie Eilshemius suggested use of agar; 100 °C to melt, 50 °C to solidify Richard Petri developed Petri dish, a container for solid culture media.

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Joseph Lister – 1860’s, English surgeon that applied ideas of the germ theory to surgery, remembered the work of Semmelweis in Hungary in the 1840’s, if a Dr. would wash their hands childbed fever was prevented. He knew that phenol would kill bacteria; put 2 and 2 together and treated wounds with phenol - and no infection (phenol is the basic agent of today’s – Lysol) 1. First antiseptic use in surgery, chemicals used as agents on tissue before surgery (tissue treated with an antimicrobial agent – antiseptic, betadine ) disinfectants are chemicals, used on a surface 2. Also proved that microbes cause surgical infections (today’s scourge –MRSA) Joseph Lister (1827-1912 )

Joseph Lister:

Joseph Lister Developed Antiseptic Surgery Sterilized with Heat Swabbed with Carbonic Acid Reduced Post Surgical Infections Joseph Lister ( 1827-1912 )

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Antisepsis in surgery

Antisepsis in surgery:

Antisepsis in surgery

Aseptic Technique…..:

Technique used by microbiologists to prevent microbial contamination of themselves, which may result in infection, contamination of the environment they are working in (e.g. fomites ), and contamination of the specimen they are working on, which is especially important when a pure culture is desired Contributors : Ignaz Semmelweis (hand washing as a means of minimizing surgical infection) Joseph Lister (use of chemical antimicrobials for the "sanitization" of objects that come into contact with surgical wounds) Aseptic Technique…..

The Birth of Modern Chemotherapy:

Treatment with chemicals is chemotherapy. Chemotherapeutic agents used to treat infectious disease can be synthetic drugs or antibiotics. Antibiotics are chemicals produced by bacteria and fungi that inhibit or kill other microbes. Quinine from tree bark was long used to treat malaria. 1910: Paul Ehrlich developed a synthetic arsenic drug, salvarsan , to treat syphilis. 1930s: Sulfonamides were synthesized. The Birth of Modern Chemotherapy

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Paul Ehrlich , German doctor, wanted to find a “magic bullet” an agent that would kill the disease agent without hurting the patient. 1. Developed Salvarsan , “salvation from syphilis”agent 2. This was an arsenical – arsenic compound, that was effective against syphilis Antimicrobial agent, medicine to treat a microbial disease, it was chemical – chemotherapy Paul Ehrlich (1854-1915 )

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Alexander Fleming - Scottish physician and bacteriologist – 1928-Observed mold growing on a bacteria culture, there was a ring of clearing around the mold where the bacteria didn’t grow, the mold was later found to be a Penicillium species and the naturally secreted chemical was called penicillin, an antibiotic 1. Antibiotics are natural agents 2. Synthetic drugs are chemicals produced in labs (sulfas) 3. Problems with them - toxicity, resistance, allergic reactions 4. Fleming’s work - shelved until early WWII, sulfas were failing, needed penicillin to cure battle field wounds 5. Now have thousands of antibiotics and synthetics (and a significant problem – resistance) Alexander Fleming (1881-1955 )

The Birth of Modern Chemotherapy:

1928: Alexander Fleming discovered the first antibiotic. He observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus . 1940s: Penicillin was tested clinically and mass produced. The Birth of Modern Chemotherapy Similar to Figure 1.5

Flemming and Penicillium:

Flemming and Penicillium

Watson and Crick, DNA, 1953:

Watson and Crick, DNA, 1953

Salk; IPV:

Salk; IPV

Sabin, OPV:

Sabin, OPV

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