Chapter 1 MICRO

Germ Theory

However, Pasteur's discovery that bacteria are responsible for spoiling wine led to his "hypothesis" in 1857 that microorganisms are also responsible for diseases, This idea that came to be known as the Germ theory of disease.

How Can Microbes Be Classified?

Linnaeus' taxonomic system developed "scientific names" for all living things Called Scientific nomenclature or Binomial nomenclature All living creatures are named with two names. The genus and species.

Types of Microorganisms

Microorganisms are now categorized in two different ways. They are even categorized into: Five Kingdoms or Three Domains

The Early Years of Microbiology (pp. 2-7)

The First Observations The first microscope is attributed to several names like Zacharias Janssen and Giovanni Faber (who coined the name microscope for Galileo in 1625). The First Observations In 1665 Robert Hooke inspired the use of microscopes for scientific exploration with a detailed account of the interior construction of living tissue based on the use of a microscope. Robert Hooke's "Micrographia" had a huge impact, largely because of its impressive illustrations. Hooke coined the term cell (for microorganisms)

Scientific nomenclature 2

The genus is always capitalized and the species is always in lower case. Staphylococcus aureus is correct e. Coli is not correct.

Five Kingdoms

Animals Plants (Algae) Fungi Protozoa Monera (bacteria and archae)

Microbial Genetics

While working with the bacterium Streptococcus pneumoniae , Oswald Avery, Colin MacLeod, and Maclyn McCarty determined that genes are contained in molecules of DNA. Avery, MacLeod, and McCarty determined genes are contained in molecules of DNA

Three Domains of Microorganisms:

1. Archaea 2. Bacteria 3. Eukarya Eukaryotes "with nucleus" Both are Prokaryotes "pre-nucleus" Archaea = Archaeobacteria are prokaryotes that live in unusual habitats (Hot springs, Antarctic, Great Salt Lake).-ancient cells Bacteria = Eubacteria or "true" bacteria Archaea and Bacteria are both very primitive, simple mircoorganisms Eukarya - advanced organisms with cells that contain a Nucleus. much more advanced than Prokaryotes. Fungi Eukaryotic cells Obtain food from other organisms Possess cell walls Fungi Composed of Mushrooms (macroscopic) Molds - multicellular; have hyphae; reproduce by sexual and asexual spores Yeasts - unicellular; reproduce asexually by budding; some produce sexual spores

Smallpox

A disease called Smallpox greatly affected the development of Western civilization. The first stages of the decline of the Roman Empire (AD 108) coincided with a large-scale epidemic: the plague of Antonine, which accounted for the deaths of almost 7 million people (from Smallpox). Smallpox was introduced by the Spanish and Portuguese conquistadors. The disease decimated the local population and was instrumental in the fall of the empires of the Aztecs and the Incas.

Lister

A few years later, English physician Joseph Lister (1827-1912) advanced the idea of antisepsis in health care settings, Joseph Lister observed that compound bone fractures (bone sticking out of skin) could result in death (from infection) while recovery from simple fractures was without incident. After looking at Pasteur's work showing microbes were in the air, can spoil food, and caused animal diseases, Lister used a chemical disinfectant to prevent surgical wound infections.

Pasteurization

After his work, Pasteur's name became a household word when he developed "Pasteurization," a process of heating the grape juice just enough to kill most contaminating bacteria without changing the juice's basic qualities, so that it could then be inoculated with yeast to ensure that alcohol fermentation occurred. Along with wine... Today pasteurization is used routinely on milk to eliminate pathogens that cause diseases such as bovine tuberculosis and brucellosis; Pasteurization is also used to eliminate pathogens in juices and other beverages, and other foods. Wine, beer, bread, cheese, yogurt, etc. Pasteur thus began the field of industrial microbiology (or biotechnology) in which microbes are intentionally used to manufacture products (Chap 25).

The Cell Theory

After van Leeuwenhoek's discoveries, scientists made more and more observations. Between 1838-39 Matthias Schleiden and Theodor Schwann deduced that all living matter composed of cells. The CELL THEORY. Schleiden and Schwann's theory accepted the first two tenets of modern cell theory. All living things are made of cells The cell is the basic unit of structure, function, and organization in all organisms. In 1855, Rudolf Virchow showed that all cells come from pre-existing cells, thus completed the classical cell theory: All living organisms are composed of one or more cells. The cell is the basic unit of structure, function, and organization in all organisms. All cells come from preexisting cells.

Classification

All living organisms can be classified as either eukaryotic or prokaryotic. Eukaryotes are organisms whose cells contain a nucleus composed of genetic material surrounded by a distinct membrane. Prokaryotes are unicellular microbes that lack a true nucleus.

Gene Therapy

An exciting new area of study is the use of recombinant DNA technology for Gene therapy, Gene therapy is a process that involves inserting a missing gene or repairing a defective one in human cells. In such procedures, researchers insert a desired gene into host cells, where it is incorporated into a chromosome and begins to function normally. Chapter 8 examines recombinant DNA technology and gene therapy in more detail.

John Snow (1813-1858)

Another English physician, John Snow, also played a key role in setting standards for good public hygiene to prevent the spread of infectious diseases. Snow had been studying the propagation of cholera and suspected that the disease was spread by a contaminating agent in water. In 1854, he mapped the occurrence of cholera cases during an epidemic in London and showed that they centered around a public water supply on Broad Street. John Snow also set standards in good public hygiene. He mapped the occurrence of cholera in London. He interviewed the public; including those with the disease, those associating with people with the disease, and those with no connection to the disease. His interviews directed him to the source of the infection: Broad St. Pump Water Station. Though Snow did not know the cause of cholera, his careful documentation of the epidemic highlighted the critical need for adequate sewage treatment and a pure water supply. His study was the foundation for two branches of microbiology — Infection control and Epidemiology, which is the study of the occurrence, distribution, and spread of disease in humans.

Spontaneous generation

Aristotle (around 350 B.C. Greece) Best known and accepted scientist of his day proposed Spontaneous generation Living things can arise from nonliving matter (from a "vital life force") Food spoiling, maggots emerging on meat, mice in grain Spontaneous generation was accepted as fact for around 2000 years The notion of a spontaneous generation gave rise to a wide variety of exotic beliefs such as: Snakes arising from horse hairs standing in stagnant water, Mice from bags of grain. Maggots from decaying meat. For many people this was especially strong evidence that spontaneous generation did occur. Redi put meat into jars. One jar was kept open while another jar was covered with a cork or mesh. Meat in open jars (exposed to flies) was soon infested with maggots While decaying meat kept isolated from flies (sealed jars), maggots never developed As a result, scientists began to doubt Aristotle's theory of Spontaneous generation

Includes

Bacteria, Algae, Fungi, Protozoans Viruses. Not cells

What Are the Basic Chemical Reactions of Life?

Biochemistry is the study of metabolism —that is, the chemical reactions that occur in living organisms. Biochemistry began with Pasteur's work on fermentation by yeast and bacteria, and with Buchner's discovery of enzymes in yeast. But by the early 1900s many scientists thought that the metabolic reactions of microbes had little to do with the metabolism of plants and animals. Albert Kluyver and his student C. B. van Niel proposed that basic biochemical reactions are shared by all living things, that these reactions are relatively few in number. In 1926 Kluyver published the now classic paper, "Unity in Biochemistry," a paper helped establish that all organisms are unified. Kluyver famously expressed the idea with the aphorism "From elephant to bacterium - it is all the same".

The Early Years of Microbiology 2

Classification of living things Shortly after Leeuwenhoek made his discoveries, a Swedish botanist named Carolus Linnaeus (1707-1778) developed a Taxonomic system — for naming plants and animals and grouping similar organisms together. Biologists still use a modification of Linnaeus's taxonomy today.

Lazzaro Spallanzani's Experiments

Concluded that: Needham failed to heat vials sufficiently to kill all microbes or had not sealed vials tightly enough Microorganisms exist in air (on dust) and can contaminate experiments Spontaneous generation of microorganisms does not occur However, Critics said sealed vials did not allow enough air for organisms to survive and that prolonged heating destroyed the "life force" Today, we know that the boiling time was insufficient to kill any endospores of microbes and the cooling of flasks left open to the air could cause microbial contamination. Needham did not use proper sterile technique. The debate continued until the French chemist Louis Pasteur conducted experiments with S-shaped flasks that finally laid to rest the theory of spontaneous generation

Redi's Experiments

First to "question" the mighty Aristotle A physician named Francesco Redi He was most well-known for his series of experiments, in 1668 One of the first experiments that refuted "spontaneous generation" involved maggots emerging naturally from rotting meat.

The Golden Age of Microbiology

Golden Age of Microbiology" from the late 19th century to the early 20th century, Microbiologists competed to be the first to answer several questions about the nature of microbial life. Those questions were: Is spontaneous generation of microbial life possible? What causes fermentation? What causes disease? How can we prevent infection and disease? Some philosophers and scientists of the past thought living things arose from Three processes: asexual reproduction,-call making exact copy of itself sexual reproduction-making a whole new cell from nonliving matter-

Microbial Role in Disease

Ignaz Semmelweis was a physician on the obstetric ward of a teaching hospital in Vienna. In 1848 he observed that women giving birth in the wing where medical students were trained died from puerperal fever at a 20 times higher rate than women attended by midwives or women who gave birth at home. Semmelweis hypothesized that "cadaver particles" from the hands of the medical students caused puerperal fever, and he required medical students to wash their hands in chlorinated lime water before attending births. Mortality from puerperal fever in the subsequent year dropped precipitously. Semmelweis began requiring medical students to wash their hands with chlorinated lime water, a substance long used to eliminate the smell of cadavers. Mortality in the subsequent year dropped from 18.3% to 1.3%. Despite his success, Semmelweis handwashing was ridiculed by the director of the hospital and eventually forced to leave. He returned to his native Hungary, where his insistence on handwashing met with general approval when it continued to produce higher patient survival rates. Ironically Semmelweis died at an old age from puerperal fever

Robert Koch KOCHS POSTULATES

Koch initiated careful microbiological laboratory techniques in his search for disease agents. He developed techniques to isolate bacteria, stain cells, estimate population size, sterilize growth media, and transfer bacteria between media.

Examples of Scientific names

Staphylococcus aureus Describes the clustered arrangement of the cells (staphylo-), the shape of cell (coccus) and the golden color (aureus) of the colonies. Esherichia coli (E.coli) Honors the discoverer, Theodor Escherich, describes the bacterium's habitat, (the large intestine or colon).

Viruses

Viruses are not grouped the same way. Very small (cannot be seen with common microscope) Not considered "alive" Yet can be cause of deadly diseases

What is Microbiology

What is Microbiology? Microbiology is the study of microorganisms (or microbes), Microorganisms are too small to be seen with the naked eye.

John Needham's Experiments

After Redi's experiments, Most scientists did not believe animals could arise spontaneously, but Most DID believe microbes could... Spontaneous generation for small microbes again gained favor when John Needham He showed that if a broth was boiled (presumed to kill all life) and then allowed to sit in the open air, it became cloudy.

Edward Jenner

In 1789, the English physician Edward Jenner tested his hypothesis that a milder disease called cowpox provided protection against potentially fatal smallpox. Jenner noticed that milkmaids rarely got small pox (a very deadly disease of the time.) He concluded that the milkmaids were exposed to the milder cowpox disease which made them immune to small pox. After he intentionally inoculated a girl with pus collected from a milkmaid's cowpox lesion, the girl developed cowpox, which she survived. When Jenner then infected the same person with smallpox pus, he found that she had become immune to smallpox. Note that experiments that intentionally expose human subjects to deadly pathogens are considered "unethical" today. Jenner coined the term vaccination from the latin vacca for cow (Vaccinia virus causes cowpox) The protection is called Immunity Vaccination became established a safe treatment for preventing smallpox, and began the field of Immunology — the study of the body's specific defenses against pathogens. Edward Jenner well known around the world for his innovative contribution to immunization and the ultimate eradication of smallpox. While Jenner's work is widely regarded as the foundation of immunology the fact is he was neither the first to suggest that infection with cowpox conferred specific immunity to smallpox nor the first to attempt cowpox inoculation for this purpose. Ex - George Washington ordered his soldiers to be inoculated in 1777 because more men were falling to smallpox than to Redcoat muskets.

The Golden Age of Microbiology 5

In 1884, Danish scientist Christian Gram developed a staining technique involving application of a series of dyes that leave some microbes purple and others pink. The "Gram Stain" is still the most widely used staining technique today; it distinguishes Gram-positive-purple from Gram-negative bacteria-pink Question 4 How Can We Prevent Infection and Disease? Semmelweis and handwashing Lister's antiseptic technique Nightingale and nursing Snow - infection control and epidemiology Jenner's vaccine - field of immunology Ehrlich's "magic bullets" - field of chemotherapy In the mid-19th century, modern principles of hygiene, such as those involving sewage and water treatment, personal cleanliness, and pest control, were not widely practiced. Medical facilities and personnel lacked adequate cleanliness, and nosocomial infections, those acquired in a health care facility, were rampant.

The Golden Age of Microbiology 4

In 1897, experiments by the German scientist Eduard Buchner (1860-1917) demonstrated the presence of enzymes, (cell-produced proteins) that promote chemical reactions such as fermentation. No live microorganisms required. His work began the field of biochemistry and the study of metabolism.

Antibiotics

In 1928 Alexander Fleming discovered the first antibiotic. He observed that the fungus called Penicillium made a chemical, penicillin, that killed Staphylococcus aureus.

The Modern Age of Microbiology 6

In 1958, George Beadle and Edward Tatum, working with the bread mold, established that a gene's activity is related to the function of the specific protein coded by that gene. Other researchers, also working with microbes, determined the exact way in which the rates and mechanisms of genetic mutation, and the methods by which cells control genetic expression.

What Causes Fermentation?

In 19th-century France spoiled Acidic wine was threatening the livelihood of many grape growers. The initial question was, "Why does the wine spoil?" but this led to a more fundamental question "What causes the fermentation of grape juice into wine?"

Scientific nomenclature

In Binomial nonenclature, the first name, Genus, signifies a group of similar organisms. The second name, Specific epithet or species, signifies a unique organism with a specific set of genes. For example, the wolf (or dog) is called Canis lupus. The coyote is called Canis latrans. Golden Jackal is called Canis aureus In Scientific nomenclature, this is true for microorganisms as well:  1. Genus and  2. species. A common bacteria living is your intestines is called Escherichia coli-genus or E. coli.-species Even though English is the universal language of science, Scientific names are "Latinized" so they can be universally recognized (worldwide). Some common endings for Latin adjectives in the three genders (masculine, feminine, neuter) are -us, -a, -um Carolus Linnaeus real name is Carl Linné Others endings include -or, -or, -us (e.g. minor, meaning "smaller"). Scientific names can: Describe the organism Honor a scientist who discovered it. Identify its habitat.

Experimental "Control"

In order for experiments (and their results) to be accepted as valid by the scientific community, they must include appropriate control groups — Control groups are groups that are treated exactly the same as the other groups in the experiment, except for the one variable that the experiment is designed to test. In Pasteur's experiments on spontaneous generation, for example, his "control flasks" contained a sterile infusion composed of all the nutrients living things need, as well as air made available through the flasks' "swan necks." His "experimental flasks" for testing his hypothesis — that microbes would reach (and subsequently grow in) the infusion through contact with dust particles — were exposed to exactly the same conditions, plus contact with the dust in the bend in the neck. Because exposure to the dust was the only difference between the control and experimental groups, Pasteur was able to conclude that the microbes growing in the infusion arrived on the dust particles.

Introduction of Penicillin changed the world.

In the 1940s (WWII): Penicillin was tested clinically and mass produced. (The beginning of cures of the many of the diseases that ravaged mankind) Selman Waksman was a biochemist and microbiologist at Rutgers University whose research promoted the discovery of Streptomycin and many other antibiotics. Waksman coined the word "Antibiotic"

Two examples of gene sequencing data:

In the 1970s, Carl Woese discovered that significant differences in nucleic acid sequences among organisms clearly reveal that cells belong to one of three major groups bacteria, archaea, or eukaryotes and not just two groups as previously thought. Nucleic acids are the building blocks of DNA and RNA, like beads on a necklace.

John Needham

John Needham (1713 -1781) was an English biologist and Roman Catholic priest. He did experiments using gravy or broth in containers. The experiments consisted of briefly boiling a broth mixture and then cooling the mixture in an open container to room temperature. Later, the flasks would be sealed, and microbes would grow a few days later. Needham's experiments seemed to show that there was a vital life force that produced spontaneous generation of microbes.

Unity in Biochemistry

Kluyver and van Niel - microbes used as model systems for biochemical reactions. Showed that many biochemical reactions (such as respiration) are shared by all living things, are few in number, and involve the transfer of electrons and hydrogen ions. Now, scientists could begin to use microbes as model systems to answer questions about metabolism in other organisms. Today, biochemical research has many practical applications, including the design of herbicides and pesticides; the diagnosis of illness; the treatment of metabolic diseases; and the design of drugs to treat various disorders. Microbial genetics is the study of inheritance in microorganisms. Throughout the 20th century, researchers made significant advances in our understanding of how genes work. For example, research established that a gene's activity is related to the function of the specific protein coded by that gene, and they determined the exact way in which genetic information is translated into a protein.

Lazzaro Spallanzani

Lazzaro Spallanzani challenged Needham's experiments by using a slightly different protocol (a longer boiling time and leaving the cover on while boiling), Spallanzani did not have any microbes grow in his sealed flasks, contradicting Needham's findings.

Microbiology

Life is thought to have existed here on earth for the past 3.5 billion years (give or take a few). But it wasn't until 350 years ago that we observed cells, and thus the basic unit of life. The early years of microbiology brought the first observations of microbial life and the initial efforts to organize them into logical classifications.

Microbial Role in Disease

Lister developed an antiseptic (phenol) for surgical instruments Deaths among his patients were reduced by two-thirds. Even had a product named after him. Florence Nightingale the founder of modern nursing, introduced antiseptic techniques that saved the lives of innumerable soldiers during the Crimean War of 1854-1856. She was a dedicated English nurse who succeeded in introducing simple cleanliness into nursing practice. Nightingales arranged for each patient's filthy clothes and dressings to be replaced or cleaned at a different location, thus removing many sources of infection. She thoroughly documented statistical comparisons to show that poor food and unsanitary conditions in the hospitals were responsible for the deaths of many soldiers.

Microbes in our lives

Microorganisms: - Some are beneficial to humans and animals, symbiotic = normal microbiota or microflora of your skin and guts - Some are used in food and chemical industry - Maintain earth's ecological balance - Some cause disease The number causing disease is very small But those are of most importance to us... The subject lies at the heart of many biosciences, including: Immunology Biochemistry Genetics Molecular Biology

Recombinant DNA Technology

Molecular biology is applied in Recombinant DNA technology commonly called genetic engineering, Geneticists manipulate genes in microbes, plants, and animals for practical applications. For instance, scientists have inserted genes from human cells into E.coli bacteria, What could a bacteria possibly to with a human gene? Recombinant DNA technology is a boon to hemophiliacs, who previously depended on clotting factor isolated from donated blood, which was possibly contaminated by life-threatening viral pathogens. by inserting a gene into bacteria (that codes for clotting factor proteins), the bacteria can replicate (very quickly) AND produce the clotting factor proteins. Recombinant DNA technology also produces insulin for diabetics. by inserting insulin producing gene into bacteria, and then harvesting the insulin they produce.

Florence Nightingale (1820-1910)

Nightingale's investigations of the British Army's sanitary conditions led to drastic changes. She showed that improved sanitation decreased the incidence of epidemic typhus. She was later admitted into the British Statistical Society for her work.

Four basic steps of the scientific method

Observation of a phenomena The scientist generates a hypothesis — that is, a potential answer to the question. - An educated guess. The scientist designs and conducts an experiment to test the hypothesis. Based on the observed results of the experiment, the scientist either accepts, rejects, or modifies the hypothesis.

Microbial genetics in Chapter 7.

Over the past 40 years, advances in microbial genetics developed into several new disciplines that are among the fastest growing areas of scientific research today, including: Molecular biology Recombinant DNA technology Gene therapy Linus Pauling proposed in 1965 that gene sequences could provide a means of understanding possible evolutionary relationships and processes, establishing taxonomic categories that more closely reflect these relationships, and identifying the existence of microbes that have never been cultured in a laboratory.

Louis Pasteur's Experiments

Pasteur developed "swan-necked flasks" that allowed "air in" When the "swan-necked flasks" remained upright, no microbial growth appeared. But, When the flask was tilted (on its side), dust from the bend in the neck seeped back into the flask and made the infusion cloudy with microbes within a day.

Pasteur

Pasteur is remembered for his breakthroughs in the causes and preventions of diseases, and his discoveries have saved countless lives ever since. He reduced mortality from puerperal fever, and created the first vaccines for rabies and anthrax. His medical discoveries provided direct support for the germ theory of disease and its application in clinical medicine. He is regarded as one of the three main founders of bacteriology, together with Ferdinand Cohn and Robert Koch, and is popularly known as the "father of microbiology."

Chemotherapy

Paul Ehrlich hypothesized that chemicals could be used to kill microorganisms inside a host (person). Ehrlich studied many different chemicals to find a "magic bullet" that would destroy all pathogens while remaining nontoxic to humans. By 1908, he had discovered a synthetic arsenic drug called salvarsan was used to treat syphilis and African sleeping sicknesses. Ehrlich's discoveries began the branch of medical microbiology known as Chemotherapy. Chemicals to treat 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.

Question 3 - What Causes Disease?

Prior to the 1800s, disease was attributed to various factors such as evil spirits, sin, imbalances in body fluids, foul vapors and being a dweeb. Italian philosopher Girolamo Fracastoro (1478-1553) did conjectured as early as 1546 that "germs of contagion" cause disease, But the idea that germs might be invisible living organisms was not discovered until 130 years later by Leeuwenhoek.

Hooke

Robert Hooke was member of The Royal Society of London for Improving Natural Knowledge, Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London." It is possibly the oldest such society in existence. Included great scientists of Hooke's time such as Sir Isaac Newton and Robert Boyle. Here "the government" is investing in science.

Scientific names

Scientific names are either italicized OR underlined. Both Streptococcus pneumoniae and Bacillus anthracsis are correct. Any other way is incorrect (and will result in points off on a test or research paper). Use italicized

Koch's Experiments also led to discoveries in `

Simple staining techniques First photomicrograph of bacteria Techniques for estimating CFU/ml Use of steam to sterilize media Use of Petri dishes Aseptic techniques Bacteria as distinct species

Disease

Since a particular disease is typically accompanied by the same symptoms in all affected individuals, early investigators suspected that diseases such as cholera, tuberculosis, and anthrax are each caused by a specific germ, called a pathogen. Today we know that diseases are also caused by genetics, environmental toxins, and allergic reactions; thus, the germ theory applies only to infectious disease.

Protozoa

Single-celled Eukaryotes Similar to animals (name means little animals) in their nutritional needs and cellular structure Typically live freely in water; some are parasites Most reproduce asexually; some reproduce sexually Most are capable of locomotion by Pseudopodia - cell extensions that flow in direction of travel Cilia - numerous, short, hairlike protrusions that propel organisms through environment Flagella - extensions of a cell that are fewer, longer, and more whiplike than cilia

The Golden Age of Microbiology 3

The controversy over spontaneous generation was largely a philosophical one among men who conducted research to gain basic scientific knowledge. They had no practical goals in mind — except, perhaps, personal acclaim in the form of financial support, honor, and prestige. However, the second question that moved microbial studies forward in the 1800s had tremendous practical applications.

The Scientific Method

The debate over spontaneous generation led in part to the development of a generalized way of researching science called the Scientific Method Questions are answered through observations of the outcomes of carefully controlled experiments, instead of by conjecture or according to the opinions of any authority figure. Sorry Aristotole The scientific method provides a framework for conducting an investigation rather than a rigid set of specific "rules," The scientific method consists of four basic steps:

The Early Years of Microbiology

The greatest contribution came from Antoni van Leeuwenhoek a Dutch tailor and lens grinder He used his Lens to examine the quality of cloth He used his "microscopes" to examine microbes as well. Also looked at the first living microorganisms He sandwiched a very small glass ball lens between the holes in two metal plates riveted together, and with an adjustable-by-screws needle attached to mount the thread or specimen. The First Observations van Leeuwenhoek examined drops of water with scrapings from his teeth and visualized "tiny animals" that were really bacteria, fungi, algae, and single-celled protozoa; Your book may credit him for using the first microscope. Van Leeuwenhoek's microscopes allowed him to begin the first examination and documentation of the microbial world. He was the first to observe living microorganisms he originally referred to them as animalcules. By end of 19th century, these organisms were called microorganisms Van Leeuwenhoek reported the existence of protozoa in 1674 and of bacteria in 1676. He gets more credit for work thanks to his diligent records and drawings of his discoveries.

Koch's postulates:

The suspected microorganism must be found in every case of the disease and be absent from healthy hosts. The microorganism must be isolated and grown outside the host. When the microorganism is introduced to a healthy, susceptible host, the host must get the same disease. The same agent must be re-isolated from the diseased experimental host.

Fermentation

These questions were so important to wine makers that they funded research concerning fermentation,  hoping scientists could develop methods to Promote the production of alcohol and Prevent spoilage by acid during fermentation. Scientists of the 1800s used the word fermentation to mean not only the formation of alcohol from sugar, but also other chemical reactions such as the formation of lactic acid, the putrefaction of meat, and the decomposition of waste. Many scientists asserted that air caused these fermentation reactions; Others insisted that living organisms were responsible. This of course linked to debate over spontaneous generation

Bacteria and Archaea

Unicellular and lack nuclei (Prokaryotes) Much smaller than eukaryotes Found everywhere there is sufficient moisture; some found in extreme environments ALL Reproduce asexually Bacteria - cell walls contain peptidoglycan; most do not cause disease and some are beneficial Archaea cell walls composed of polymers other than peptidoglycan NO peptidoglycan

Algae

Unicellular or multicellular Photosynthetic Simple reproductive structures Categorized on the basis of pigmentation, storage products, and composition of cell wall

The Modern Age of Microbiology 7

What Role Do Microorganisms Play in the Environment? Bioremediation uses living bacteria, fungi, and algae to detoxify polluted environments Recycling of chemicals such as carbon, nitrogen, and sulfur How Do We Defend Against Disease? Serology The study of blood serum Immunology The study of the body's defense against specific pathogens Chemotherapy Fleming discovered penicillin Domagk discovered sulfa drugs What Will the Future Hold? Microbiology is built on asking and answering questions The more questions we answer, the more questions we have

Robert Koch

While Pasteur was the chief investigator in made many discoveries regarding disease, he was not the chief investigator of disease. Investigations in etiology (the study of causation of disease) were dominated by Robert Koch (1843-1910). As the founder of modern bacteriology, he is known for his role in identifying the specific causative agents of tuberculosis, cholera, and anthrax and for giving experimental support for the concept of infectious disease. One of Koch's greatest achievements was the elaboration, in his publications on tuberculosis, of a set of steps that must be taken to prove the cause of any infectious disease. The four steps are known as Koch's postulates:

Pasteur's Experiments

Wine makers hired Louis Pasteur to solve their problem. Pasteur's investigations into the cause of fermentation led to the discovery that yeast can grow with or without oxygen, and yeast cells ferment grape juice to produce alcohol. Bacteria ferment grape juice to produce acids (vinegar, lactic acid) These discoveries suggested a method to prevent the spoilage of wine by heating the grape juice just enough to kill contaminating bacteria, so that it could then be inoculated with yeast. Pasteurization, the use of heat to kill pathogens and reduce the number of spoilage microorganisms in food and beverages, is an industrial application widely used today.