Microbiology - Chapter 1

What factors contribute to the emergence of an infectious disease?

- Evolutionary changes in existing organisms - Spread of known diseases to new geographic regions or populations by modern transportation - Increased human exposure to new, unusual infectious agents in areas that are undergoing ecologic changes such as deforestation and construction contribute to the emergence of infectious diseases. - EIDs also develop as a result of antimicrobial resistance

Infectious disease

A disease that is caused by a pathogen and that can be spread from one individual to another.

Biofilm

A microbial community that usually forms as a slimy layer on a surface.

What is spontaneous generation?

A theory that many scientists in the second half of the 19th century adhered to said that some forms of life could spontaneous form from nonliving matter, a vital force forms life.

Antibiotics

Antimicrobial agents that have been produced by bacteria or fungi

Who is Anton Van Leeuwenhoek?

Anton Van Leeuwenhoek was the first person to actually view microorganisms. He called them "animalcules" and made detail drawings of the "animalcules" he found in rainwater, in his own feces and in teeth plaque.

Lister is associated with?

Aseptic surgery

Give some examples of emerging infectious diseases

Avian Influenza A - bird flu MRSA - Methicillin-resistant staphylococcus aureus West Nile Encephalitis Bovine Spongiform Encephalopathy - Mad Cow disease Escherichia Coli O157:H7 Ebola Hemorrhagic Fever - Ebola virus Cryptosporidiosis AIDS

What are certain types of microorganisms?

Bacteria Archaea Fungi Protozoa Algae Viruses Multicellular animal parasites

Which group of microbes are prokaryotes? Which are eukaryotes?

Bacteria and Archaea are prokaryotes. Fungi, protozoa, algae, and multicellular parasites are eukaryotes.

Primarily, which types of microorganisms return carbon dioxide to the atmosphere when they decompose organic wastes and dead plants and animals?

Bacteria and fungi

List at least four beneficial activities of microorganism

Bacteria recycle carbon, nutrients, sulfur, and phosphorous that can be used by plants and animals. Bacteria degrade organic matter in sewage. Bacteria degrade or detoxify pollutants such as oil and mercury.

Describe some of the destructive and beneficial actions of microbes.

Benefits: Decompose organic waste Producers in the ecosystem by photosynthesis Produce industrial chemicals such as ethanol and acetone Produce fermented foods such as vinegar, cheese, and bread Produce products used in manufacturing (cellulase) and disease treatment (insulin). Harms: Certain microorganisms are pathogenic - cause disease

Who is Carl Woese and what is his contribution to the study of microbiology?

Carl Woese devised a system of classification based on the cellular organization of organisms. It groups all organisms in three domains as follows: 1. Bacteria (cell walls contain a protein-carbohydrate complex called peptidoglycan) 2. Archaea (cell walls, if present, lack peptidoglycan) 3. Eukarya, which includes the following: ● Protists (slime molds, protozoa, and algae) ● Fungi (unicellular yeasts, multicellular molds, and mushrooms) ● Plants (mosses, ferns, conifers, and flowering plants) ● Animals (sponges, worms, insects, and vertebrates)

Who established the nomenclature system used today?

Carolus Linnaeus established the nomenclature system in 1735

What is cell theory and what discovery gave birth to this theory?

Cell theory is the theory that all living things are composed of cells and come from preexisting cells. Robert Hooke's observation of a thin slice of cork and his conclusion that life's smallest structural units were little boxes or cells gave cell theory a start.

Synthetic drugs

Chemotherapeutic agents prepared from chemicals in the laboratory.

Recombinant DNA

DNA made from two different sources ****

Pathogenic

Disease Producing microorganisms

Nomenclature - How are organisms named?

Each organism has two names --- the genus (plural: genera) - first name, capitalized; the specific epithet (species name) follows, not capitalized. both names are underlined or italicized.

How was vaccination discovered and who discovered it?

Edward Jenner, a British physician, was trying to find a way to protect people from smallpox. His milkmaid told him that she had already been sick from cowpox and thus could not get sick from smallpox. Jenner tested the girl's theory by using a health 8 year old volunteer and scratching the person's skin with a cowpox-contaminated needle. The scratch turned into a blister and after being mildly sick for a few days, the 8 year old child became healthy once again and never again contracted cowpox or smallpox. This is called vaccination.

Salvarsan was developed by

Ehrlich

Who developed the theory of immunity?

Ehrlich

Who discovered a chemotherapeutic agent against syphilis?

Ehrlich

Multicellular Animal Parasites

Eukaryotes Multicellular animals Parasitic flatworms and roundworms are called helminths Microscopic stages in life cycles

Fungi

Eukaryotes - Have a distinct nucleus chitin cell walls Use organic chemicals for energy Fungi cannot carry out photosynthesis Can reproduce sexually or asexually. Most typical fungi are molds - Multicellular, consisting of masses of myclia which are composed of filaments called hyphae.

Protozoa

Eukaryotic microbes Move by pseudopods (false feet), flagella or cilia. Can reproduce asexually or sexually Varieties of shapes Live either as free entities or as parasites Absorb or ingest organic chemicals

Briefly explain Frencesco Redi's experiment. What was his objective?

Francesco Redi was against the theory of spontaneous generation. His intent for performing this experiment was to disprove the theory. He took six jars and filled them with decaying meat. He left three of these jars open and sealed the other three. He observed that the open jars had maggots and sealed jars had none. Flies could lay their eggs on the mean in the unsealed jars and that is why maggots formed but those who adhered to the theory of spontaneous generation were not convinced still. They claimed that air was a necessary component of spontaneous generation and because Redi had sealed the other three jars, he hindered spontaneous generation. Redi responded by tweaking his experiment a little and rather than completing sealing the three jars, he merely covered them with a gauze netting; allowing air to flow through but still keeping flies out. He observed that the netted jars had no maggots while the jars that were left completely exposed had maggots. Redi's findings dealt a huge blow to the theory of spontaneous generation.

Gene therapy

Inserting a missing gene or replacing a defective gene in human cells.

What evidence supported spontaneous generation?

John Needham and Lazzaro Spallanzani's experiments supported the theory of spontaneous generation. John Needham was an english scientist who heated nutrient broth effectively killing the microorganisms in the broth before pouring the liquid into two sealed flasks. He found that after the broth had cooled, there were microorganisms in the broth. Needham claimed that microbes developed spontaneously from the fluids. The conclusions of this experiment led him and other scientists to renew their faith in the theory of spontaneous generation. Lazzaro Spallanzani was an Italian scientist who tested out a similar experiment as John Needham with the main difference being that he heated the broth in the flask after it had been sealed whereas Needham heated the broth first and then sealed the flask. Spallanzani's experiment led to no microorganism forming and he concluded that in Needham's version of the experiment, microbes from the air had contaminated the heated broth before the flask was sealed. His conclusions however were met with criticism as supporters of the theory of spontaneous generation claimed that sealing the flask before heating it had deteriorated the vital force and the seal also prevented the vital force from the surroundings to enter into the broth. This was further emphasized due to a recent finding by Anton Laurent Lavoisier who 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. This led to increased support for the theory of spontaneous generation and the theory of biogenesis was weakened.

Briefly explain John Needham's experiment and what effect did it have on the development of the theory of spontaneous generation?

John Needham was an english scientist who heated nutrient broth effectively killing the microorganisms in the broth before pouring the liquid into two sealed flasks. He found that after the broth had cooled, there were microorganisms in the broth. Needham claimed that microbes developed spontaneously from the fluids. The conclusions of this experiment led him and other scientists to renew their faith in the theory of spontaneous generation.

What is the significance of Koch's postulates?

Koch's postulates was the first actual proof that bacteria (microbes) caused disease. Robert Koch was looking to find out where anthrax, a disease that was killing cattle and sheep came from. He took blood from a cattle that had died of anthrax and cultured the bacteria on nutrient before injecting it into a healthy animal. He observed that the animal was beginning to resemble the same symptoms of the cattle that had died from anthrax eventually also succumbing to the disease. He compared the two bacteria in the blood of these two animals and found them to be one and the same. Koch thus established Koch's postulates, a sequence of experimental steps for directly relating a specific microbe to a specific disease. These same criteria have been invaluable in investigations proving that specific microorganisms cause many diseases.

Briefly explain Lazzaro Spallanzani's experiment and what effect did it have on the development of the theory of biogenesis?

Lazzaro Spallanzani was an Italian scientist who tested out a similar experiment as John Needham with the main difference being that he heated the broth in the flask after it had been sealed whereas Needham heated the broth first and then sealed the flask. Spallanzani's experiment led to no microorganism forming and he concluded that in Needham's version of the experiment, microbes from the air had contaminated the heated broth before the flask was sealed. His conclusions however were met with criticism as supporters of the theory of spontaneous generation claimed that sealing the flask before heating it had deteriorated the vital force and the seal also prevented the vital force from the surroundings to enter into the broth. This was further emphasized due to a recent finding by Anton Laurent Lavoisier who 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. This led to increased support for the theory of spontaneous generation and the theory of biogenesis was weakened.

Explain the theory of biogenesis

Living cells can arise only from preexisting cells

Briefly explain Louis Pasteur's experiment and what effect it had on the theory of spontaneous generation?

Louis Pasteur conducted two separate experiments. In his first experiment, he heated nutrient broth in two flasks, sealing one and leaving the other one open. He observed after a few days that the unsealed flask had microbes in it while the other remained pure. He concluded that microbes in the air contaminated the unsealed flask. In his second experiment, he placed nutrient broth into two long necked flasks and then altered the shape of two flasks by bending their necks into an S shape. After this, he heated the two flasks without sealing them. He noted after the broth had cooled down in the S shaped flasks, that there were no microbes in the broth because the unique shape of the flask allowed air to come into contact with the broth but the curved neck trapped any airborne microorganisms from contaminating the broth. Pasteur demonstrated that microorganisms are present in the air and can contaminate sterile solutions, but that air itself does not create microbes. His experiments completely revoked the theory of spontaneous generation and proved biogenesis once and for all.

What is the distinction between microbial genetics and molecular biology?

Microbial genetics - studies the mechanisms by which microorganisms inherit traits. Molecular biology - studies how genetic information is carried in molecules of DNA and how DNA directs the synthesis of proteins

Normal Microbiota

Microorganisms that are found in and on the human body. They do not usually cause disease and can be beneficial. Normal microbiota prevent growth of pathogens Normal microbiota produce growth factors such as folic acid and vitamin K.

Germ Theory of Disease

Microorganisms travel through the air, water, through animals to infect other animals, human beings and even plants. This theory was affirmed by findings from Agostino Bassi in 1835 as he showed that silkworm disease was caused by a fungus. Later on in 1865, Pasteur believed another silkworm disease was caused by a protozoan. An English surgeon named Joseph Lister was aware of Pasteur's work of relating microorganisms with animal diseases and he was also aware of Ignaz Semmelweis's work who had noticed that physicians who did not disinfect their hands as they treated one patient after the other spread infections such as childbirth fever to mothers. Although disinfectants were not used during this time, Lister knew that phenol killed bacteria so he began treating surgical instruments with a phenol solution. This disinfectant technique reduced infections and deaths extensively to the point that it led other surgeons to follow suit. Additionally, Lister's cautious measures to disinfect surgical instruments before using them on an another patient gave more credibility to the germ theory of disease as it proved that killing microbes on surgical instruments prevented and drastically reduced the rate of infection.

Microorganisms (Microbes)

Minute living things that individually are usually too small to be seen with the unaided eye. Examples: Bacteria Fungi Protozoa Microscopic Algae Viruses

Viruses

Most can only be seen with an electron microscope due to how small they are. Simple structure - Core made up of either DNA or RNA, core is surrounded by a protein coat - coat may be enclosed in a lipid envelope. Can only reproduce when they are in a living host. Without a host, the virus is inert Acellular

The process of using just enough heat to kill most of the bacteria that cause spoilage was developed by

Pasteur

Fermentation

Pasteur showed that microbes are responsible for fermentation, a process in which sugar is converted to alcohol to make beer and wine. Microbial growth is also responsible for food spoilage.

What is Pasteurization?

Pasteurization is the application of a high heat for a short time and it is a technique that was developed by Louis Pasteur who demonstrated that these food spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine preventing the bacteria from fermenting the wine into vinegar.

What was Ehrlich's magic bullet?

Paul Ehrlich, a German physician, was the imaginative thinker who fired the first shot in the chemotherapy revolution. As a medical student, Ehrlich speculated about a "magic bullet" that could hunt down and destroy a pathogen without harming the infected host. He found a chemotherapeutic agent called salvarsan, an arsenic derivative effective against syphilis. The agent was named salvarsan because it was considered to offer salvation from syphilis and it contained arsenic.

How was penicillin discovered?

Penicillin, the first antibiotic was discovered by Alexander Fleming by a complete accident. Penicillin is an antibiotic produced by a fungus.

Algae

Photosynthetic eukaryotes Cellulose cell walls Sexual and asexual reproductive forms Produce molecular oxygen and organic compounds

Archea

Prokaryotes Lack peptidoglycan but do have cell walls Found in extreme environments: methanogens - produce methane as a waste product. Extreme halophiles - live in extremely salty environments Extreme thermophiles - live in extremely hot sulfurous environments

Differentiate biotechnology from recombinant DNA technology.

Recombinant DNA technology is a technique for biotechnology that enables bacteria and fungi to produce a variety of proteins, including vaccines and enzymes. Use of microorganisms to produce some common foods and chemicals. Such practical applications of microbiology are called biotechnology.

Who was Robert Hooke? What did he observe?

Robert Hooke was an Englishman who reported the world that life's smallest structural units were "little boxes," or "cells". After improving his microscope, he was able to see individual cells.

Who developed the germ theory of disease?

Robert Koch

Which scientist is credited for discovering cell theory?

Rudolf Virchow is credited for cell theory based on the works of Robert Hooke who observed cork and came to the conclusion that living things are composed of little boxes or cells.

Who challenged the case for spontaneous generation with the concept of biogenesis?

Rudolph Virchow

Bacteria

Single celled Organisms Prokaryotes Peptidoglycan cell walls Reproduce by binary fission Bacteria move by using a flagella For energy: Use organic or inorganic chemicals or photosynthesis

How was spontaneous generation disproved?

Spontaneous generation was disproved by Louis Pasteur and his experiments using S shaped flasks. Louis Pasteur conducted two separate experiments. In his first experiment, he heated nutrient broth in two flasks, sealing one and leaving the other one open. He observed after a few days that the unsealed flask had microbes in it while the other remained pure. He concluded that microbes in the air contaminated the unsealed flask. In his second experiment, he placed nutrient broth into two long necked flasks and then altered the shape of two flasks by bending their necks into an S shape. After this, he heated the two flasks without sealing them. He noted after the broth had cooled down in the S shaped flasks, that there were no microbes in the broth because the unique shape of the flask allowed air to come into contact with the broth but the curved neck trapped any airborne microorganisms from contaminating the broth. Pasteur demonstrated that microorganisms are present in the air and can contaminate sterile solutions, but that air itself does not create microbes. His experiments completely revoked the theory of spontaneous generation and proved biogenesis once and for all.

Gram is associated with?

Staining techniques

Genomics

Study of all of an organism's genes

What is the period that is referred to the Golden Age of Microbiology and which scientists spearheaded the movement?

The period is between 1857-1914 and was spearheaded by Louis Pasteur and Robert Koch who established microbiology as a science. During this time, discoveries included evidence establishing the relationship between microbes and disease, immunity and antimicrobial drugs.

Bacteriology

The study of bacteria

Mycology

The study of fungi

Immunology

The study of immunity

Parasitology

The study of protozoa and parasitic worms

Microbial ecology

The study of the relationship between microorganisms and their environment

Virology

The study of viruses

Bioremediation

The use of living organisms to detoxify and restore polluted and degraded ecosystems

Biotechnology

The use of microbes to produce foods and chemicals.

Chemotherapy

Treatment of disease by using chemical substance is called chemotherapy. Chemotherapy is based on the fact that some chemicals are more poisonous to microorganisms than to the host infected by the microbes.

Who discovered the structure of DNA?

Watson and Crick

Gene therapy is used to treat

cystic fibrosis

Emerging infectious diseases

new or changing diseases showing an increased incidence in the recent past or a potential to increase in the near future

Robert Koch won the Nobel prize for identifying the cause of which disease?

tuberculosis