 |  | Pseudomonas aeruginosa Colonization of P. aeruginosa on a human lung. This bacterium can cause chronic lung infections in people with cystic fibrosis. |
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 |  | Scanning electron micrograph of Pseudomonas aeruginosa Colonies of P. aeruginosa are often the cause of chronic lung infections in individuals suffering from cystic fibrosis. |
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 |  | Attached bacteria Scanning electron micrograph of a young bacterial biofilm that formed on the lower surface of an oil slick on the Athabasca River. |
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 |  | Attached bacteria Scanning electron micrograph of a young bacterial biofilm that formed on the lower surface of an oil slick on the Athabasca River. |
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 |  | Pipe corrosion caused by a biofilm
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 |  | Extracellular matrix Bacterial cells enmeshed in extracellular matrix material, creating a biofilm |
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 |  | Biofilms on catheter tips Biofilms can be a problem in medical settings where artificial materials are introduced into the human body, allowing bacteria to colonize and cause infection. |
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 |  | Phagocytes on a biofilm Scanning electron micrograph of the outer surface of a Tenckhoff catheter recovered from the peritoneum of a chronic ambulatory peritoneal dialysis (CAPD) patient. It shows the extensive microbial biofilm that had developed and a large number of phagocytes that were attracted to this surface by the presence of sessile bacteria. |
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 |  | Toilet bowl biofilm Experimental èreactor systemî set up to study the formation of biofilm in toilets as part of an industrial-sponsored project at the CBE |
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 |  | Heap leach pad Heap leach operations, like this one operated by Kennecott, can contain a million tons of ore, piled a leak-proof pad. Adding water on top promotes the growth of microbes and starts the bioleach. |
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 |  | Palaeolyngbya Ancient fossilized bacterium, Palaeolyngbya, from the Bitter Springs Chert |
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 |  | 16S ribosomal RNA Secondary structure of T. thermophilus 16S rRNA, with its 5ç, central, 3ç-major, and 3ç-minor domains shaded in blue, magenta, red, and yellow, respectively. |
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 |  | Euprymna scolopes The squid Euprymna scolopes (a) and its light organ (b). The luminous bacterium Vibrio fischeri colonizes the light organ, providing camouflage to the squid. |
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 |  | Light organ of Euprymna scolopes
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 |  | Polymerase chain reaction (PCR) 1) Double-stranded DNA in the sample is heated to generate single strands. 2) Sequence specific primers are added, which anneal to desired sites on the DNA. 3) Nucleotides and heat-tolerant DNA polymerase allow for primer extension at elevated temperature. 4) The result is two new copies of double-stranded DNA. The process is repeated to generate multiple specific dsDNA molecules. |
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 |  | The methane cycle Methanogens are intolerant to oxygen so they thrive in anoxic sediments. The methane they produce is a carbon and an energy source for methane oxidizers in overlaying water. |
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 |  | The nitrogen cycle Bacteria are key to the cycling of nitrogen in ecosystems. Different species are involved in decomposition and ammonification, nitrification, denitrification, and nitrogen fixation. |
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 |  | The "Shrub of Life" Proposed by W. Ford Doolittle, this view of early evolution suggests multiple primitive cells as ancestors to the three domains, and illustrates lateral gene transfer among early organisms. |
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 |  | Terms describing varying energy and carbon sources
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 |  | A comparison of key characteristics from the three domains of life
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