Micro Lecture ch1

• Microorganisms are important in the maintenance of an ecological balance on earth
• -they produce oxygen and are usefull in carbon fixation
• -decompostion of waste matter and recycling
• Some microorganisms live in humans and other animals and are needed to maintain good health
• -Fungi and bacteria
• Some microorganisms are used to produce foods and chemicals
• -they're in yeast to make bread, beer and wine and the bacteria that ferment our yogurt and cheeses
• Some microorganisms cause disease

• Bacteria
• -unicellular organisms
• -prokaryotic (no nucleus)
• -3 basic shapes: bacillus, coccus, and spiral
• -most have a peptidoglycan cell wall
• -divide by binary fission
• -may possess flagella
• -bacteria can use a wide range of chemical substances for their nutrition
• Protozoa
• -Unicellular (small single cell organisms)
• -Eukaryotes
• -obtain nourishment by absorption or ingestion thru specialized structures
• Fungi
• -fancy term for mushrooms and yeast
• -Multicellular
• -Eukaryotic
• -obtain nutrients by absorbing organic material from their environment
• Microscopic animals and plants
• Algae
• -Unicellular or Multicellular
• -Eukaryotes
• -obtain nourishment by photosynthesis
• -produce oxygen and carbohydrates that are used by other organisms
• Animal Parasites
• -helminths (like flatworms, roundworms)
• -Multicellular
• -the microscopic stages int he life cycle of helminths are id'd by traditional microbiological procedures
• Viruses
• -non-living organisms

• Prokaryotes:
• archaea (ancient bacteria; 200+ species)
• bacteria (true bacteria; 10,000 named; 10-100 million estimated)
• Eukaryotes:
• protists (amoeba, red and brown algae, slime molds; 250,000)
• fungi (mushrooms and yeast; 100,000)
• plants and green algae (350,000)
• animals (1,000,000+)

Eubacteria - true bacteria; no nucleus or organelles

archaea- odd bacteria that live in extreme environments, high salt, heat, etc

Eukarya - have a nucleus and organelles

• SPONTANEOUS GENERATION
• the idea that living organisms could arise from nonliving matter
• BIOGENESIS
• living cells can arise ONLY from preexisting cells

He disproved spontaneous generation of microorganisms

Pasteur's discoveries led to the development of aseptic techniques (keeping microbes where you want to have them and keeping them out of where you dont want them) used in labs and medical procedures to prevent contamination by microorganisms

beginning with Pasteur's work, discoveries included the relationship between microbes and disease, immunity and antimicrobial drugs

developed a rabies vaccine

showed microbes caused fermentation and spoilage

a heating process called pasteurization is used to kill bacteria in some alcoholic beverages and milk

along with Agostino Bassi, Pasteur showed a causal relationship between microorganisms and disease

Robert Koch proved that microorganisms cause disease. He used a sequence of procedures, now called Koch's postulates (1876), that are used today to prove that a particular microorganism causes a particular 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 proved that a bacterium causes anthrax and provided the experimental steps, Koch's postulates, to prove that a specific microbe causes a specific disease

• 1. microorganisms degrade dead plants and animals and recycle chemical elements to be used by living plants and animals
• 2. bacteria are used to decompose organic matter in sewage
• 3. bioremediation processes use bacteria to clean up toxic wastes
• 4. bacteria that cause diseases in insects are being used as biological controls of insect pests. Biological controls are specific for the pests and do not harm the enviroment
• 5. using microbes to make products such as foods and chemicals is called biotechnology
• 6. using recombinant DNA, bacteria can produce important substances such as proteins, vaccines and enzymes
• 7. in gene therapy, viruses are used to carry replacements for defective or missing genes into human cells
• 8. genetically modified bacteria are used in agriculture to protect plants from frost and insects and used to improve shelf life of produce

An infectious disease is one in which pathogens invade a susceptible host

• Respiratory infectious
• -pneumonia
• -influenza
• Diarrheal diseases
• -cholera
• -dysentery
• -typhoid
• Tuberculosis
• Malaria
• Measles
• Hep B
• Tetanus
• Parasitic diseases

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

• SARS (severe acute respiratory syndrome)
• AIDS (Acquired immunodeficiency syndrome)
• HIV (human immunodeficiency virus)
• Viral
• -west nile encephalitis
• -avian influenza A (bird flu)
• Prion
• -bovine spongiform encephalophathy (mad cow)
• Bacterial
• -invasive group A (streptococcus)
• Protozoa
• -Cryptosporidiosis

• most are living organisms
• falls in 3 main domains
• -archaea
• -bacteria
• -eukarya
• the non living organisms are the
• -viruses

Living things that are too small to be seen with the unaided eye

disease causing microbes

single celled organism

• prokaryotic (unicellular)
• Lack peptidoglycan in cell walls (key difference between them and true bacteria)
• live in extreme environments
• include:
• -methanogens (methane producing)
• -extreme halophiles (extremely salty)
• -extreme thermophiles (extremely hot)

A single individual or species from this domain is called an archaeon (sometimes spelled "archeon"). They have no cell nucleus nor any other membrane-bound organelles within their cells. In the past they were viewed as an unusual group of bacteria and named archaebacteria, but since the Archaea have an independent evolutionary history and show many differences in their biochemistry from other forms of life, they are now classified as a separate domain in the three-domain system. In this system the phylogenetically distinct branches of evolutionary descent are the Archaea, Bacteria and Eukaryota.

• true bacteria
• no nucleus or organelles
• a large group of bacteria characterized by a rigid cell wall and, in motile types, flagella; the true bacteria

• have nucleus and organelles
• includes:
• -protists
• -fungi
• -plants
• -green algae
• -animals

any organism having cells in each of which the genetic material is in a single DNA chain, not enclosed in a nucleus. Bacteria and archaeans are prokaryotes

• Prokaryotes (unicellular)
• have peptidoglycan cell walls
• found everywhere!
• for energy, they use organic chemicals, inorganic chemicals or even photosynthesis

can do about anything and are about everywhere

very large group of microorganisms comprising one of the three domains of living organisms. They are prokaryotic, unicellular, and either free-living in soil or water or parasites of plants or animals

• eukarytoes
• have chitin cell walls
• most are terrestrial (forest)
• they use organic chemicals for energy (do NOT photosynthesize)
• molds and mushrooms are multicellular
• yeasts are unicellular

A fungus (pronounced /ˈfʌŋɡəs/; pl. fungi[3] or funguses[4]) is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds (British English: moulds), as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria. One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants, which contain cellulose. These and other differences show that the fungi form a single group of related organisms, named the Eumycota (true fungi or Eumycetes), that share a common ancestor (a monophyletic group).

• eukaryotes
• no cell walls (only plasma membrane)
• aquatic and soil inhabitants
• absorb or ingest organic chemicals (go out and hunt food)
• may be motile via pseudopods, cilia or flagella

Protozoa (from the Greek words proto, meaning "first", and zoa, meaning "animals") is a grouping of eukaryotes,[1] many of which are motile.

• eukaryotes
• cellulose cell walls (cellulose like wood and paper)
• algae= most aquatic (single celled)
• plants= most terrestrial (multicellular organisms like grass and trees)
• use photosynthesis for energy
• produce molecular oxygen and organic compounds

• eukaryote
• multicellular animals
• parasitic flatworms and round worms are called helminths
• microscopic states in life cycles

• NON LIVING BECAUSE THEY CANNOT REPRODUCE THEMSELVES
• acellular (lacking cells)
• consist of DNA or RNA core
• core is surrounded by a protein coat
• sometimes coat may be enclosed in a lipid envelope
• viruses are replicated only when they are in a living host cell

Parasitic worms or helminths (pronounced /ˈhɛlmɪnθs/) are a division of eukaryotic parasites that, unlike external parasites such as lice and fleas, live inside their host.[1] They are worm-like organisms that live and feed off living hosts, receiving nourishment and protection while disrupting their hosts' nutrient absorption, causing weakness and disease. Those that live inside the digestive tract are called intestinal parasites. They can live inside humans as well as other animals. Approximately 3 billion people globally are infected with helminths.

one in which pathogens invade a susceptible host

An infectious disease is a clinically evident illness resulting from the presence of pathogenic biological agents, including pathogenic viruses, pathogenic bacteria, fungi, protozoa, multicellular parasites, and aberrant proteins known as prions. These pathogens are able to cause disease in animals and/or plants. Infectious pathologies are also called communicable diseases or transmissible diseases due to their potential of transmission from one person or species to another by a replicating agent (as opposed to a toxin).[

• Germ theory states that many diseases are caused by the presence and actions of specific micro-organisms within the body. The theory was developed and gained gradual acceptance in Europe and the United States from the middle 1800s. It eventually superseded existing miasma and contagion theories of disease and in so doing radically changed the practice of medicine. It remains a guiding theory that underlies contemporary biomedicine.
• The observations and actions of Ignaz Semmelweis, Joseph Lister and John Snow would retrospectively be acknowledged as contributing to the acceptance of germ theory. But it was the laboratory researches of Louis Pasteur in the 1860s and then Robert Koch in the following decades that provided the scientific proof for germ theory. Their work opened the door to research into the identification of disease-causing germs and potential life-saving treatments

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

• Koch's postulates: In 1890 the German physician and bacteriologist Robert Koch set out his celebrated criteria for judging whether a given bacteria is the cause of a given disease. Koch's criteria brought some much-needed scientific clarity to what was then a very confused field.
• Koch's postulates are as follows:

• 1. The bacteria must be present in every case of the disease.
• 2. The bacteria must be isolated from the host with the disease and grown in pure culture.
• 3. The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.
• 4. The bacteria must be recoverable from the experimentally infected host.

However, Koch's postulates have their limitations and so may not always be the last word. They may not hold if:

• 1. The particular bacteria (such as the one that causes leprosy) cannot be "grown in pure culture" in the laboratory.
• 2. There is no animal model of infection with that particular bacteria.

A harmless bacteria may cause disease if:

• 1. It has acquired extra virulence factors making it pathogenic.
• 2. It gains access to deep tissues via trauma, surgery, an IV line, etc.
• 3. It infects an immunocompromised patient.

• Not all people infected by a bacteria may develop disease-subclinical infection is usually more common than clinically obvious infection.
• Despite such limitations, Koch's postulates are still a useful benchmark in judging whether there is a cause-and-effect relationship between a bacteria (or any other type of microorganism) and a clinical disease.

• Pasteurization is a process of heating a food, usually liquid, to a specific temperature for a definite length of time, and then cooling it immediately. This process slows microbial growth in food. The process of heating wine to preserve it longer was known in China since AD.1117, and is documented in Japan in 1568 in the diary Tamonin-nikki, but the modern version was created by the French chemist and microbiologist Louis Pasteur, after whom it is named. The first pasteurization test was completed by Louis Pasteur and Claude Bernard in April 1862. The process was originally conceived as a way of preventing wine and beer from souring.
• Unlike sterilization, pasteurization is not intended to kill all micro-organisms in the food. Instead pasteurization aims to reduce the number of viable pathogens so they are unlikely to cause disease (assuming the pasteurized product is stored as indicated and consumed before its expiration date). Commercial-scale sterilization of food is not common because it adversely affects the taste and quality of the product. Certain food products, like dairy products, are superheated to ensure pathogenic microbes are destroyed