SGU Microbiology: FTV/FTM – Flashcards
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Unlock answers| Why do we study microbiology? |
| Found everywhere & an important part of our environment Significant impacts on human and animal health. Majority of microorganisms are BENEFICIAL 1) Studies of microorganisms can help us to understand processes in other life forms Simpler to study (unicellular or simple multicellular) than complex life forms. Can grow large numbers relatively quickly and easily |
| What is the Significance of microorganisms? |
| Important part of the food chain. Aid in digestion & provide food for humans. Produce valuable industrial products such as antibiotics and steroids. Degrade organic waste and toxic materials. Help us to understand genetic processes. Important cause of human, plant and animal diseases. |
| Medical/Veterinary Microbiology |
| Identification of microorganisms; prevention & treatment of disease |
| Aquatic microbiology |
| Water purification, breakdown of waste materials |
| Food microbiology |
| Safe production of food; prevention of spoilage |
| Industrial microbiology |
| Production of e.g., enzymes or antibiotics |
| Agricultural microbiology |
| Understanding & dealing with plant diseases; understanding relationship between plants & microorganisms |
| What are microorganisms? |
| MICROSCOPIC life forms, i.e., we need a microscope to see them (most of them anyway). |
| The major groups are? |
| Bacteria Fungi Viruses Algae Protozoa |
| The major fields of study are? |
| Bacteriology, Mycology, Algology, Protozoology |
| Bacteria (plural) Bacterium (singular) |
| Single celled organisms NO cell nucleus: PROKARYOTIC Reproduce ASEXUALLY Size range: micrometers (1 ?m = 0.000001 cm or 1/100,000th of a cm) Can absorb nutrients or synthesize their own Can be MOTILE or NON-MOTILE |
| Fungi (plural) Fungus (singular) |
| Yeasts True nucleus: EUKARYOTIC Unicellular Reproduce asexually (cell division), budding or sexually >Moulds Eukaryotic Multicellular Reproduce sexually & asexually |
| Viruses (plural) Virus (singular) |
| ACELLULAR Composed of nucleic acid (DNA or RNA) and proteins Can’t replicate outside of a host cell (INTRACELLULAR PARASITES) Size range: nanometers (1 nm = 0.000000001cm or 1/100 millionth of a cm) |
| Algae (plural) Alga (singular) |
| Single celled or multicellular Eukaryotic Size range: micrometers to feet Photosynthesize for food production Not medically important |
| Protozoa (plural) Protozoan(singular) |
| Unicellular Eukaryotic Size range: micrometers to mm Reproduce asexually & sexually |
| Van Leeuwenhoek |
| (1632 – 1723) Created early single-lens microscopic One of first to describe microscopic organisms “animacules” |
| spontaneous generation? |
| the idea that life can arise from nothing (abiogenesis) Theory (Aristotle): life arose spontaneously from dead organic matter |
| Francesco Redi & Lazzaro Spallanzani |
| Redi challenged the theory of spontaneous regeneration by covering meet with a fine mesh. Spallanzani boiled broth in a sealed container. Neither experiences convinced the public |
| Louis Pasteur & spontaneous generation |
| killed spontaneous generation by the invention of the swan necked flask that trapped bacteria in the neck of the flask |
| Louis Pasteur also ...? |
| Determined how the process of fermentation worked, Eduart with Buchner made the rabies vaccine |
| Agonstino BassI |
| Credited with “parasite/germ” theory of disease; was the 1st to demonstrate microorganisms could cause disease brDescribed fungus associated with an epidemic disease of silkworms |
| Robert Koch |
| Further clarified relationship between microorganisms and disease Vaccine for B. anthracis and tuberculosis developed a series of criteria called Koch’s Postulates. |
| What are the 4 Koch Postulates? |
| 1.The suspected causative organism should always be present along with the specific disease and absent in healthy animals 2.The suspected organism can be grown in pure culture 3.Organisms taken from the pure culture should cause disease in a healthy animal 4.The organism can be re-isolated and shown to be the same as the original. |
| When do Koch's postulates not work? |
| When there is no animal model When the organism is unculturable When organism is normal flora but opportunistic |
| Lady Mary Montague |
| Brought the practice of variolation back from Ottoman Empire Used for prevention of smallpox |
| Edward Jenner |
| Observed that milkmaids exposed to cowpox while milking rarely contracted smallpox. "father of vaccines"Tested theory by inoculating small boy with material from cowpox lesions Then exposed the boy to smallpox |
| John Snow |
| Father of modern epidemiology Identified source of cholera outbreak in London |
| Ignaz Semmelweis |
| Identified that handwashing decreased infection rates in hospital patients. (milk fever) |
| Joseph Lister |
| Recognised important of Pasteur’s work & applied it with regard to control of infections. Theorised: infections of open surgical wounds = due to microorganisms in air.Used early aseptic technique: sprayed air with carbolic acid (phenol) |
| Paul Ehrlich |
| Searched for “magic bullet” to kill microorganisms without harming humans. Initiated branch of medical microbiology called “chemotherapy” |
| Alexander Fleming |
| (Re)Discovered of penicillin |
| Gerhard Domagk |
| Discovered an antimicrobial dye (prontosil) long with Fleming, laid the groundwork for modern antimicrobial chemotherapy (use of antibiotics) |
| Culture |
| population of microorganisms (also used to describe the techniques for growing bacteria) |
| Pure culture |
| Population containing only one type (species) of microorganism |
| Mixed culture |
| Population containing >1 species of microorganisms. In natural environments, most microorganisms exist as mixed culture |
| Features used for characterisation of mircoorganisms? |
| Morphological Chemical Cultural Metabolic Antigenic Genetic Pathogenicity Ecological |
| Morphological |
| Cell size, shape & structures Cell arrangement Staining reaction Motility Developmental forms |
| Chemical |
| Presence of proteins, carbohydrates, etc. Enzymes |
| Cultural |
| Nutritional requirements Physical conditions required for growth |
| Metabolic |
| How energy is obtained and used Types of chemical reactions |
| Antigenic |
| Determination of antigenic properties |
| Genetic |
| Characteristics of hereditary material Presence of other genetic information, e.g., plasmids |
| Pathogenicity |
| Ability to cause disease. Not all microorganisms are pathogenic! |
| Ecological |
| Habitat & distribution in nature Interaction with other species |
| What system do we use for classifying microorganisms? |
| Currently accepted: Carl Woese’s 3 DOMAINS system
Uses 16S RNA for differentiation (Phylogenetic characterisation) |
| What are the 3 domains? |
| Bacteria Archaea Eucarya |
| The system by which we name Bacteria? |
| TAXONOMY: Carolus Linnaeus’s classification. Sometimes called “bionomial classification” (literally “two names”). = formal system of ordering, classifying & naming |
| In taxonomy the seven descending groups after the Domain are? |
| Kingdom > Phylum > Class > Order > Family > Genus > Species |
| What must we know in order to identify a bacteria to species and genus level |
| Uses a combination of:1.Physical characteristics 2.Growth and energy requirements 3.Metabolic processes carried out |
| INOCULATION |
| Process of transferring or introducing microbial cells into fresh growth media. What’s being transferred = the inoculum. Sources might be: CLINICAL SAMPLE - blood, urine, CSF, feces, etc 2.HABITAT SAMPLE - soil, water, sewage, food, etc 3.EXISTING PURE CULTURE - from ATCC culture collection or frozen stocks |
| INCUBATION |
| Place the Microorganism in conditions necessary to obtain growth |
| INOCULUM |
| Tool being used to innoculate |
| Blood, urine, CSF, feces, etc. |
| CLINICAL SAMPLES |
| Soil, water, sewage, food, etc |
| HABITAT SAMPLE |
| From ATCC culture collection or frozen stocks |
| EXISTING PURE CULTURE (reference microbes) |
| MEDIA (plueral) Medium (singular) |
| Function: to provide the nutrients that will enable the microorganisms to grow. Can be: liquid, semi-solid, or solid. |
| Liquid media |
| Water based solutions, do not solidify at temperatures above freezing, flow freely in containers, ie: BROTHS, MILKS |
| Semi-solid media |
| Mid-way between liquid and solid. Soft custard-like consistency Exact solidity depends on amount of solidifying agent (agar/gelatin - 0.3-0.5%) Uses: to determine motility, localize reaction at specific sites |
| Solid media |
Firm, set jelly-like surface, allows cells to form discrete colonies Necessary for ISOLATION & SUBCULTURING Liquid media can be converted to solid media by addition of a gelling agent –usually AGAR – before media is autoclaved. Solid media is sometimes referred to just as “agar”. Agar = powdered seaweed. |
| What are the 2 Forms of solid media? |
| LIQUEFIABLE: reversible solid, agar, thermoplastic NON LIQUEFIABLE: NOT thermoplastic ie. cooked meat, potato slices, egg media. |
| DEFINED media |
| Precise amounts of inorganic compounds added to water Usually contains single carbon source. |
| COMPLEX media |
| Mixture of inorganic and organic compounds |
| SELECTIVE media |
| contains 1 or more inhibitory agents e.g., dyes, acid, antibiotics. Examples: MANNITOL SALT AGAR - 7.5% NaCl, inhibitory to most human pathogens SABOURAUD’S AGAR (for growth of Fungi) - pH 5.6 (acid); inhibits bacteria by including antibiotics. |
| DIFFERENTIAL media |
| Allows for growth of several types BUT highlights differences between them. (e.g., based on colony colour, formation of gas or a precipitate) CONTAINS DYES (differential agents) - act as pH indicators, colour change due to production of acid or base Example: EMB agar |
| MacConkey agar |
| Both Selective & differential o Selective due to: High Bile salt concentration (prevents growth of Gram +ve bacteria). Differential due to: inclusion of lactose and neutral red (a pH indicator). Production of acid as the bacteria utilize the lactose changes the pH indicator and produces pink colonies |
| REDUCING media |
| Addition of Thioglycollic acid or cystine absorbs oxygen/slows penetration of oxygen THUS reducing availability = REQUIRED for growing ANAEROBIC BACTERIA |
| CARBOHYDRATE FERMENTATION media |
| Specific sugars included to look for bacterial ability to ferment them, producing acid and/or gas. REQUIRED for BIOCHEMICAL/IDENIFICATION TEST |
| TRANSPORT media |
| Maintains and preserves samples from when they are taken until they get the lab for culture. Examples: STUART’S + AMIES contains salts, buffers & absorbents. Prevents cell destruction, pH changes, toxic substances. Doesn’t actually support growth. |
| ASSAY media |
| Used when carrying out specific tests e.g, looking at effectiveness of antimicrobial agents such as disinfectants or antibiotics |
| ENUMERATION meida |
| Used in food and water industry: allows enumeration (counting) of organisms in milk, water, food and soil samples |
| Magnification |
| enlarging the appearance of an object |
| Resolving power |
| the ability of an optical system to form distinguishable images of objects separated by small angular distances. |
| What are the different types of Light Microscopes? |
| Brightfield: Extensively used; enables viewing of stained specimens Epifluorescent:Specimen stained with a certain dye; viewed using a special filter Darkfield:Eliminates need for staining; provides contrast between specimen and background<brPhase Contrast:Eliminates need for staining; can view both structures and living organisms |
| What are the different tapes of Electron Microscopes? |
| Scanning Electron Microscope:Surface detail and 3D images Transmission Electron Microscope:Ultrastructure. Very high magnifications possible |
| What is the microscope that is has a laser and can produyce 3D images? |
| Confocal Scanning Laser Microscope: Ultrastructure; 3D images! |
| Staining |
| process involving the application of chemical STAIN/DYE to a specimen |
| Dyes |
| imparts colour to cell or cell parts - become affixed through chemical reaction 2 types: 1. BASIC (cationic) +ve charge: E.g., Crystal violet, methylene blue, Safranin. 2. ACIDIC (anionic) -ve charge: E.g., Nigrosin, India Ink. |
| What is the principle of staining? |
| “opposites attract” POSITIVE STAINING: +ve stain - sticks to specimen providing colour NEGATIVE STAINING: -ve stain - (reverse) settles around specimen boundary forms a silhouette (stains the glass slide) |
| Simple stain |
| a single stain/dye, uncomplicated procedure |
| Differential stain |
| 2 colored dyes, a primary and a counter stain: more complex procedure. Distinguishes cell types and parts |
| TYPES OF DIFFERENTIAL STAIN (for bacteria |
| Gram's stain & acid fast stain |
