Bacteria
hideActinobacteria (high-G+C) Firmicutes (low-G+C) Tenericutes (no wall)
Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Deinococcus-Thermus Fusobacteria Gemmatimonadetes Nitrospirae Proteobacteria Spirochaetes Synergistetes
Acidobacteria Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Dictyoglomi Fibrobacteres Planctomycetes Thermodesulfobacteria Thermotogae
The bacteria [bækˈtɪərɪə] (help·info) (singular: bacterium)[α] are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals. Bacteria are ubiquitous in every habitat on Earth, growing in soil, acidic hot springs, radioactive waste, water, and deep in the Earth's crust, as well as in organic matter and the live bodies of plants and animals. There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water; in all, there are approximately five nonillion (5×1030) bacteria on Earth, forming much of the world's biomass. Bacteria are vital in recycling nutrients, with many steps in nutrient cycles depending on these organisms, such as the fixation of nitrogen from the atmosphere and putrefaction. However, most bacteria have not been characterized, and only about half of the phyla of bacteria have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology.
There are approximately ten times as many bacterial cells in the human flora of bacteria as there are human cells in the body, with large numbers of bacteria on the skin and as gut flora. The vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, and a few are beneficial. However, a few species of bacteria are pathogenic and cause infectious diseases, including cholera, syphilis, anthrax, leprosy and bubonic plague. The most common fatal bacterial diseases are respiratory infections, with tuberculosis alone killing about 2 million people a year, mostly in sub-Saharan Africa. In developed countries, antibiotics are used to treat bacterial infections and in agriculture, so antibiotic resistance is becoming common. In industry, bacteria are important in sewage treatment, the production of cheese and yoghurt through fermentation, as well as in biotechnology, and the manufacture of antibiotics and other chemicals.
Once regarded as plants constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and rarely harbour membrane-bound organelles. Although the term bacteria traditionally included all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotes consist of two very different groups of organisms that evolved independently from an ancient common ancestor. These evolutionary domains are called Bacteria and Archaea.
For more information about Bacteria, read the full article at
Wikipedia.
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News tagged with bacterium
Scientists Build Anti-Mosquito Laser
Mar 16, 2009 |
4.5 / 5 (37) |
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(PhysOrg.com) -- In an effort to prevent the spread of malaria, scientists have built a laser that shoots and kills mosquitoes. Malaria, which is caused by a parasite and transmitted by mosquitoes, kills about ...
Researcher uses bacteria to make radioactive metals inert
Sep 08, 2009 |
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The Lost Orphan Mine below the Grand Canyon hasn't produced uranium since the 1960s, but radioactive residue still contaminates the area. Cleaning the region takes an expensive process that is only done in ...
A tiny frozen microbe may hold clues to extraterrestrial life
Jun 15, 2009 |
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A novel bacterium that has been trapped more than three kilometres under glacial ice in Greenland for over 120 000 years, may hold clues as to what life forms might exist on other planets.
Graduate student discovers, names bacterium linked to psyllid yellows
Biology /
Aug 12, 2008 |
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To make a discovery and get to name it is just about every scientist's dream. For one graduate student at UC Riverside that dream already has come true.
Scientists explore new window on the origins of life
Biology /
Feb 12, 2009 |
4 / 5 (9) |
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(PhysOrg.com) -- The remarkable behaviour of bacteria that have been forced to live without their protective wall has allowed Newcastle University scientists to open a new window on the origins of life on earth.
Antibiotic combination defeats extensively drug-resistant TB
Feb 26, 2009 |
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A combination of two FDA-approved drugs, already approved for fighting other bacterial infections, shows potential for treating extensively drug resistant tuberculosis (XDR-TB), the most deadly form of the ...
Researchers boost production of biofuel that could replace gasoline
Aug 19, 2009 |
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(PhysOrg.com) -- Engineers at Ohio State University have found a way to double the production of the biofuel butanol, which might someday replace gasoline in automobiles.
Researchers rapidly turn bacteria into biotech factories
Jul 26, 2009 |
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High-throughput sequencing has turned biologists into voracious genome readers, enabling them to scan millions of DNA letters, or bases, per hour. When revising a genome, however, they struggle, suffering from serious writer's ...
Bacterium helps formation of gold
Oct 07, 2009 |
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Australian scientists have found that the bacterium Cupriavidus metallidurans catalyses the biomineralisation of gold by transforming toxic gold compounds to their metallic form using active cellular mechan ...
Salmonella Spills its Secrets on the Space Shuttle
May 07, 2009 |
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Salmonella, what's gotten into you? Researchers have been asking themselves this question ever since Salmonella bacteria grown on board the space shuttle returned to Earth 3 to 7 times more virulent than S ...
Bacteria from the deep can clean up heavy metals
Jun 05, 2009 |
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A species of bacteria, isolated from sediments deep under the Pacific Ocean, could provide a powerful clean-up tool for heavy metal pollution.
New drug shows promise in the fight against malignant melanoma
Sep 29, 2009 |
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(PhysOrg.com) -- Gavin Robertson is not a man who uses the word ‘hate’ lightly, but he makes no secret of his desire to slay the dragon that is malignant melanoma.
New DNA sensors could identify cancer using graphene
Nanotechnology / Bio & Medicine
Apr 13, 2009 |
4.2 / 5 (5) |
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Kansas State University engineers think the possibilities are deep for a very thin material.
Microbe Survives in Ocean's Deepest Realm, Thanks to Genetic Adaptations
Biology /
Feb 06, 2009 |
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(PhysOrg.com) -- The genome of a marine bacterium living 2,500 meters below the ocean's surface is providing clues to how life adapts in extreme environments, according to a paper published Feb. 6, 2009, in ...
Engineered bacterium churns out two new key antibiotics
Feb 18, 2009 |
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(PhysOrg.com) -- In recent years, scientists have isolated two potent natural antibiotics — platensimycin and platencin — that are highly effective against bacterial infection, including those caused by the most dreaded drug-resistant ...
