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Micro-Ch. 1, 3, 4, 6

Roles of Microbes pathogens; food chain; autotrophs & decomposers; digestive; food & fermentation; antibiotics; biotechnology; bioremediation; disease research;
Biological Research uses Microbes for size/structure; large populations; rapid growth rate; research benefits; vaccines & antibiotics
Microorganisms bacteria, fungi, protozoa, and some algae-also have disease-causing members
Microbiology microbes organisms so small that a microscope is needed to study them
We consider (2) dimensions of the scope of microbiology 1. the variety of kinds of microbes 2. the kinds of work microbiologist do
Bacteria-(singular: bacterium) are single-celled organisms w/ spherical, rod, or spiral shapes, but a few types form filaments. Most are so small they can be seen w/ a light microscope only under the highest magnification.
Types of bacteria Some pathogens; science of bacteriology
Archaea are single celled and do not have a nucleus. Many of these are extremophiles, preferring to live in environments having extreme temperatures, pH, salinities, and hydrostatic and osmotic pressures.
Types of archaea Environmental extremophiles; Novel biochemistry
Bacteriophages viruses that infect bacteria
Viruses (acellular) entities too small to be seen with a light microscope. These replicate themselves and display other properties of living organisms only when they have invaded cells.
Protozoa (kingdom) Single celled; May be pathogenic; Science of Protozoology
Helminths (Worms) Microscopic life stages; Diagnosed Microscopically; Science of Parasitology
Arthropods (insects & similar organisms) Cause/transmit disease
CDC U.S. Centers for Disease Control and Prevention
Bioremediation organisms can be used in an important way as in cleaning up the environment, controlling insect pests, improving foods, and fighting disease.
Taxonomy Genus; Species; Viral Naming System
Microbial Taxonomy classification of microorganisms
Bacteriology Bacteria
Phycology Algae
Mycology Fungi
Protozoology Protozoa
Parasitology Parasites
Virology Viruses
Immunology How host organisms defend themselves against microbial infection
Epidemiology Frequency and distribution of diseases
Etiology Causes of disease
Infection Control How to control the spread of nosocomial-(hospital-acquired) infections
Chemotherapy The development and use of chemical substances to treat disease
Nosocomial hospital-acquired
Fields of Microbiology Infection Control; Chemotherapy; Industrial Microbiology; Biotechnology
Bubonic Plague (Black Death) Mid-fourteenth century (1347-1351) plague alone wiped out 25 million people-¼ of the population of Europe and neighboring regions-in just 5 years.
Robert Hooke (English Scientist) built a compound microscope (one which light passes through two lenses); coined the term “cell” to describe the orderly arrangement of small boxes that he saw b/c they reminded him of the cells (small, bare rooms) of monks
Anton van Leeuwenhoek (Dutch cloth merchant) everywhere he looked, he found what he called “animalcules.” He found them in stagnant water, in sick people, and even in his own mouth.
Germ Theory of Disease states the microorganisms (germs) can invade other organisms and cause disease.
Spontaneous Generation Even after it was shown that microorganisms in broth caused it to turn cloudy, people believed that the microorganisms, like the "€œworms" (fly larvae, or maggots) in rotting meat, arose from non-living things.
Carl Linnaeus Taxonomy: Genus, Species, and the Viral Naming System
Schleiden / Schwann cell theory
Francesco Redi (Italian physician) devised a set if experiments to demonstrate that if pieces of meat were covered w/ gauze so that flies couldn't reach them, no “worms” appeared in the meat, no matter how rotten it was; maggots did, however, hatch from fly eggs laid on top of the gauze.
Lazzaro Spallanzani (Italian cleric and scientist) boiled broth infusions containing organic (living or previously living) matter and sealed the flasks to demonstrate that no organisms would develop spontaneously in them.
Louis Pasteur (French chemist) finally defeated the proponents of spontaneous generation; “swan-necked” flasks; the infusions from his experiments remained sterile unless the flask was tipped so that the infusion flowed into the neck and then back into the flask.
Rabies Vaccine the first of this vaccine was developed by Pasteur & was made from the dried spinal cords of infected rabbits.
Theory definition a supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained.
Robert Koch (physician in Germany) found a way to grow bacteria in pure cultures-cultures that contained only (1) kind of organism
Ignaz Philipp Semmelweis (physician) recognized a connection b/w autopsies & puerperal (childbed) fever; physicians would go from autopsies to examining women in labor W/O washing their hands; he was ridiculed & harassed until he had a nervous breakdown & was sent to an asylum.
Angelina Hesse (American wife of one of Koch’s colleagues); suggested that Koch add agar (a thickener used in cooking) to his bacteriological media
Joseph Lister (physician) initiated the use of dilute carbolic acid on bandages and instruments to reduce infection; his techniques (the first aseptic techniques) were proven effective by the decrease of surgical infections; creator of Listerine
Edward Jenner realized that milkmaids who got cowpox did not get smallpox; inoculated his own son and an 8 yr. old boy w/ fluid from a cowpox blister; subsequently inoculated the same boys w/ smallpox; both survived.
Elie Metchnikoff (Russian zoologist) pioneer in immunology; discovered that certain cells in the body would digest microbes; named those cells: phagocytes, which literally means, “cell eating"; realized this process was a major mechanism in the bodies defense; developed several vaccines.
Martinus Beijerinck (Dutch microbiologist) used the term virus to refer to specific pathogenic (disease-causing) molecules incorporated into cells; believed these molecules could barrow for their own use existing metabolic and replicative mechanisms of the infected cells, known as host cells.
Wendell Stanley (American scientist) required development of techniques for isolating, propagating, and analyzing viruses; crystalized tobacco mosaic virus in 1935, showing that an agent w/ properties of a living organism also behaved as a chemical substance.
Alfred Hershey & Martha Chase (American biologists) demonstrated that the genetic material of some viruses is another nucleic acid, deoxyribonucleic acid (DNA).
Aureolus Paracelsus (Swiss physician) used metallic chemical elements to treat diseases (chemotherapy); antimony for general infections; mercury for syphilis
Alexander Fleming (Scottish physician) discovered lysozyme, an enzyme found in tears, saliva, and sweat, could kill bacteria; Lysozyme was the 1st body secretion shown to have chemotherapeutic properties; discovered the antibacterial properties of penicillin
Gerhard Domagk (German chemist) played an important role in chemotherapy work; the drug, prontosil, saved his daughter’s life
Recombinant Microbes Drugs; Hormones; Vaccines
Gene therapy 1990: first gene therapy patient; defective genes; insert normal-copy of the gene into some white blood cells in a laboratory and the gene-treated cells back into the body, where it is hoped to restore the “issue”.
Microscopy is the technology of making very small things visible to the human eye
Resolution refers to the ability to see two items as separate and discrete units
Resolving Power (RP) a numerical measure of the resolution that can be obtained w/ that lens; The smaller the distance b/w objects that can be distinguished, the greater the resolving power of the lens.
Reflection When light strikes an object and bounces back (giving the object color)
Transmission refers to the passage of light through an object
Absorption When the light rays neither pass through nor bounce off an object but are taken up by the object.
Refraction is the bending of light as it passes from one medium to another of different density.
Diffraction As light passes through a small opening, such as a hole, slit, or space b/w two adjacent cellular structures, the light waves are bent around the opening.
Total Magnification light microscope: is calculated by multiplying the magnifying power of the objective lens (the lens used to view your specimen) by the magnifying power of the ocular lens (the lens nearest your eye).
Bright-field Illumination The condenser used in an ordinary light microscope causes light to be concentrated and transmitted directly through the specimen.
Dark-field Illumination A microscope adapted for this has a condenser that prevents light from being transmitted through the specimen but instead causes the light to reflect off the specimen at an angle.
Phase-contrast Microscopy This has a special condenser and objective lenses that accentuate small differences in the refractive index of various structures w/in the organism; To observe them alive and unstained requires the use of this.
Nomarski Microscopy like phase-contrast microscopy, makes use of differences in the refractive index to visualize unstained cells and structures; produces much higher resolution than the standard phase-contrast microscope. (Produces almost a 3D image).
Fluorescent Antibody Staining is now widely used in diagnostic procedures to determine whether an antigen (a foreign substance such as a microbe) is present; Ultraviolet light; Natural fluorescence vs flouorochromes; FAb staining
Transmission Electron Microscope (TEM) gives a better view of the internal structure of microbes than do other types of microscopes.
Scanning Electron Microscope (SEM) is used to create images of the surfaces of specimens.
Wet Mounts in which a drop of medium containing the organisms is placed on a microscope slide, can be used to view living microorganisms.
Hanging Drop often is used w/ dark-field illumination; A drop of culture is placed on a coverslip that is encircled w/ petroleum jelly; This preparation gives good views of microbial motility. (Movement)
Smears in which microorganisms from a loopful of medium are spread onto the surface of a glass slide, can be used to view killed organisms; After a smear is made, it is allowed to air-dry completely
Heat Fixation The glass slide is quickly passed 3 or 4 times through an open flame
Heat fixation accomplishes (3) things: 1. It kills the organisms 2. It causes the organisms to adhere to the slide 3. It alters the organisms so that they more readily accept stains (dyes)
Stain, or Dye is a molecule that can bind to cellular structure and give it color
Cationic (positively charged), or basic dyes In microbiology, the most commonly used dyes
Anionic (negatively charged), or acidic dyes Other stains, such as eosin and picric acid; They are attracted to any positively charged cell materials
Negative Stains are used when a specimen-or part of it, such as the capsule-resists taking up a stain.
Capsule is a layer of polysaccharide material that surrounds many bacterial cells and can act as a barrier to host defense mechanisms.
Flagellar Staining Motility; Metal staining
Endospore Staining These walls are very resistant to penetration of ordinary stains.
Endospores A few types of bacteria produce resistant cells
Prokaryotes are among the smallest of all organisms
Coccus (plural: cocci) A spherical bacterium
Bacillus (plural: bacilli) A rodlike bacterium
Vibrio A comma-shaped bacterium
Spirillum (plural: spirilla) A ridged, wavy-shaped bacterium
Spirochete A corkscrew shaped bacterium
Pleomorphism Some bacteria vary widely in form even w/in a single culture
Peptidoglycan also called murein (from murus, wall), is the single most important component of the bacterial cell wall; It is a polymer so large that it can be thought of as one immense, covalently linked molecule.
Teichoic Acid consists of glycerol, phosphates, and sugar alcohol ribitol, occurs in polymers up to 30 units long; Cell walls of Gram-positive organisms have this additional molecule.
The Outer Membrane found primarily in Gram-negative bacteria, is a bilayer membrane; It forms the outermost layer of the cell wall and is attached to the peptidoglycan by an almost continuous layer of small lipoprotein molecules (proteins combined w/ a lipid).
Fluid-mosaic Model represents the current understanding of the structure of such membrane; phospholipids in the membrane are in a fluid state and proteins are dispersed among the lipid (fat) molecules in the membrane, forming a mosaic pattern.
Vegetative Cells cells that are metabolizing nutrients.
Structurally, an endospore consists of: core, surrounded by a cortex, a spore coat, and in some species, a delicately thin layer called the exosporium.
Flagella They often move w/ speed and apparent purpose, and they usually move by means of long, thin, helical appendages.
Chemotaxis Sometimes bacteria move toward or away from substances in their environment by a nonrandom process.
Pili (singular: Pilus) are tiny, hollow projections
Conjugation pili (or sex pili) found only in certain groups of bacteria, attach two cells and may furnish a pathway for the transfer of the genetic material DNA. This transfer process is called conjugation.
Attachment Pili or Fimbriae help bacteria adhere to surfaces, such as cell surfaces and the interface of water and air. (Shorter)
Endoplasmic Reticulum (ER) is an extensive system of membranes that form numerous tubes and plates in the cytoplasm.
Smooth (ER) synthesize lipids (fats)
Rough (ER) has ribosomes bound to its surface, which give it a rough texture and manufacture proteins.
Passive Transport the cell expends NO energy to move substances down a concentration gradient, that is, from high to lower concentration; includes simple diffusion, facilitated diffusion, and osmosis.
Active Processes the cell expends energy from ATP, enabling it to transport substances against a concentration gradient.
Simple Diffusion is the net movement of particles from a region of higher to lower concentration.
Facilitated Diffusion is diffusion down a concentration gradient and across a membrane with the assistance of special pores of carrier molecules.
Osmosis is a special case of diffusion in which water molecules diffuse across a selectively permeable membrane.
Endocytosis Form by invagination (poking in) and surround substances from outside the cell
Exocytosis the mechanism by which cells release secretions, can be thought of as the opposite of endocytosis.
Pinocytosis cell drinking
Binary Fission a cell duplicates its components and divides into two cells.
Lag Phase the organisms do not increase significantly in number, but they are metabolically active; During this phase, the individual organisms increase in size, and they produce large quantities of energy in the form of ATP.
Exponential, or Logarithmic (log) Rate Once organisms have adapted to a medium, population growth occurs at this rate; growth on a scale appears on a graph as a straight diagonal line.
Generation Time During the log phase, the organisms divide at their most rapid rate-a regular, genetically determined interval .
Stationary Phase When cell division decreases to the point that new cells are produced at the same rate as old cells die, the number of live cells stays constant.
Decline Phase, or Death Phase the number of living cells decreases at a logarithmic rate, as indicated by the straight, downward-sloping diagonal line.
Serial Dilutions you start w/ organisms in a liquid medium. Adding 1 ml of this medium to 9 ml of sterile water makes a 1:10 dilution; adding 1 ml of the 1:10 dilution 9 ml of sterile water makes a 1:100 dilution and so on.
Turbidity (a cloudy appearance) in a culture tube indicates the presence of organisms (bacteria)
Physical Factors (affecting growth of bacteria) includes pH, temperature, oxygen concentration, moisture, hydrostatic pressure, osmotic pressure, and radiation.
Nutritional Factors (affecting growth of bacteria) includes availability of carbon, nitrogen, sulfur, phosphorus, trace elements, and, in some cases, vitamins.
Acidophiles acid-loving organisms, grow best at a pH of 0.1 to 5.4
Neutrophiles exist from pH 5.4 to 8.0. Most of the bacteria that cause disease in humans are this.
Alkaliphiles alkali-loving (base-loving) organisms, exist from pH 7.0 to 11.5.
Obligate means that the organism must have the specialized environmental condition
Facultative means that the organism is able to adjust to and tolerate the environmental condition, but it can also live in other conditions.
Mesophiles which include most bacteria, grow best at room temperatures b/w 25° and 40°C. Human pathogens are included in the category, and most of them grow best near human body temperature (37°C).
Minimum Growth Temperature the lowest temperature at which cells can divide
Maximum Growth Temperature the highest temperature at which cells can divide
Optimum Growth Temperature the temperature at which cells divide most rapidly-that is, have the shortest generation time.
Obligate Aerobes such as Pseudomonas, which is a common cause of hospital-acquired infections, must have free oxygen for aerobic respiration.
Obligate Anaerobes such as Clostridium botulinum, C. tetani, and Bacteroides, are killed by free oxygen.
Fastidious they have special nutritional needs that can be difficult to meet in the laboratory.
Sporulation the formation of endospores, occurs in Bacillus, Clostridium, and a few other Gram-positive genera but has been studied most carefully in B. subtilis and B. magisterium.
Cortex (laminated layer) this protects the core against changes in osmotic pressure, such as those that result from drying.
Spore Coat keratin-like protein, which is impervious to many chemicals, is laid down around the cortex by the mother cell.
Streak Plate Method The accepted way to prepare pure cultures; uses agar plates.
Pour Plate Method makes use of serial dilutions; A series of dilutions are made such that the final dilution contains about 1,000 organisms.
Selective Medium is one that encourages the growth of some organisms but suppresses the growth of others.
Differential Medium has a constituent that causes an observable change (a color change or a change in pH) in the medium when a particular biochemical reaction occurs.
Enrichment Medium contains special nutrients that allow growth of a particular organism that might not otherwise be present in sufficient numbers to allow it to be isolated and identified.
Culture Once an organism has been isolated, it can be maintained indefinitely in a pure culture.
Aseptic Techniques minimize the chances that cultures will be contaminated by organisms from the environment or that organisms, especially pathogens, will escape into the environment.
Created by: jenilee80