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A noticeable group of viruses growing on a strong method, presumably as a result of a single microorganism
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Serge francois | Physiology of Bacteria Serge Francois
Bacterial Colony • “A noticeable group of viruses growing on a strong method, presumably as a result of a single microorganism”
Requirements for Growth • Physical: Temperature, pH, light, osmotic pressure, moisture • Chemical: Carbon, nitrogen, sulfur, phosphorus, trace elements, oxygen
Psychrophilic • Desulfofrigus oceanense (Arctic and Antarctic Oceans)
Mesophiles E. coli
Thermophiles Fossilized Microbes from Yellowstone’s Hot Springs
Temperatures • Minimum: “temperature below which bacterial growth will not take place” • Optimum: “temperature at which organisms grow best” • Maximum: “temperature above which bacterial growth will not take place”
Moisture • Maximum, optimum and minimum requirement for all microorganisms • Pathogenic bacteria are usually found in the body’s tissues • Fungal diseases are usually found on the body surface.
Heterotrophic Bacteria • 3 categories: • 1) strict (obligate) saprophyte • 2) strict (obligate) parasite • 3) facultative bacteria: • Facultative saprophyte: “prefers live organic matter as a source of nutrition but can adapt to the use of dead organic matter under certain conditions” • Facultative parasite: capable of living and growing with the nutrients that its host provides
Carbon • One of the most important requirements for microbial growth • Structural backbone of living matter • Needed for all the organic compounds that make up a living cell • ½ of the “dry weight” of a bacterial cell is carbon
Oxygen • Microbes that use molecular oxygen (aerobes) produce more energy from nutrients than microbes that do not use oxygen (anaerobes) • Reading question four: Describe the difference between obligate aerobes and obligate anaerobes.
Microaerophilic Organisms • “a microorganism that requires very little free oxygen” • only grow in oxygen concentrations that are lower than those in air • require about 2 – 10% free oxygen
Microbial Associations • Normal Flora (Microbiota) • Transient microbiota • Symbiotic relationship: “organisms live in close nutritional relationships; required by one or both members” • Distinguished by the degree to which the host organism is harmed
Parasitism • “An entertaining connection between two creatures in which one is injured and the other benefits” • Many disease-causing viruses are parasites • Typically the variety is macroscopic and the parasite is microscopic • Roundworms and flatworms are harmful viruses that are huge multi-cellular organisms
Antagonism • “Mutual resistance or opposite activity. The self-consciousness of one organism by another.” • Involves competitors among microbes • Normal microbiota secure the variety against colonization by possibly pathogenic microbes • Normal plants generate ingredients bad for the infiltrating bacteria (pH, oxygen)