Related topics: proceedings of the national academy of sciences
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.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with bacteria
Newly explored bacteria reveal some huge RNA surprises
Dec 02, 2009 |
4.9 / 5 (12) |
1
(PhysOrg.com) -- Yale University researchers have found very large RNA structures within previously unstudied bacteria that appear crucial to basic biological functions such as helping viruses infect cells ...
Plasma produces KO cocktail for MRSA
Nov 26, 2009 |
4.9 / 5 (16) |
3
MRSA (methicillin-resistant Staphylococcus Aureus) and other drug-resistant bacteria could face annihilation as low-temperature plasma prototype devices have been developed to offer safe, quick, easy and un ...
Fibre may keep asthma, diabetes at bay, study finds
Oct 28, 2009 |
4.8 / 5 (8) |
1
Insoluble dietary fibre, or roughage, not only keeps you regular, say Australian scientists, it also plays a vital role in the immune system, keeping certain diseases at bay.
Time in a bottle: Scientists watch evolution unfold
Oct 18, 2009 |
4.6 / 5 (42) |
13
A 21-year Michigan State University experiment that distills the essence of evolution in laboratory flasks not only demonstrates natural selection at work, but could lead to biotechnology and medical research ...
Chemical from Soil Bacteria Shows Potential Neuron Toxicity; Has Possible Parkinson's Implications
Medicine & Health / Neuroscience
Oct 06, 2009 |
4.7 / 5 (6) |
0
(PhysOrg.com) -- A chemical produced by common soil bacteria may kill neurons that produce dopamine, according to an article authored by University of Alabama researchers publishing Oct. 6. Dopamine neuron demise leads to ...
Comprehensive understanding of bacteria could lead to new insights into many organisms
Sep 25, 2009 |
5 / 5 (9) |
1
(PhysOrg.com) -- Investigators at Burnham Institute for Medical Research, University of California, San Diego, The Scripps Research Institute, Genomics Institute of the Novartis Research Foundation and other ...
Researchers discover new antituberculosis compounds
Sep 16, 2009 |
4.9 / 5 (7) |
0
Attempts to eradicate tuberculosis (TB) are stymied by the fact that the disease-causing bacteria have a sophisticated mechanism for surviving dormant in infected cells. Now, a team of scientists led by researchers from Weill ...
Daily bathroom showers may deliver face full of pathogens, says study
Sep 14, 2009 |
4.6 / 5 (18) |
8
While daily bathroom showers provide invigorating relief and a good cleansing for millions of Americans, they also can deliver a face full of potentially pathogenic bacteria, according to a surprising new ...
New biosensor can detect bacteria instantaneously
Chemistry / Analytical Chemistry
Sep 08, 2009 |
5 / 5 (4) |
0
A research group from the Rovira i Virgili University (URV) in Tarragona, Spain, has developed a biosensor that can immediately detect very low levels of Salmonella typhi, the bacteria that causes typhoid fever. ...
Building better bone replacements with bacteria
Sep 07, 2009 |
4.3 / 5 (3) |
0
Bacteria that manufacture hydroxyapatite (HA) could be used to make stronger, more durable bone implants. Professor Lynne Macaskie from the University of Birmingham this week (7-10 September) presented work to the Society ...
Evolution of the appendix: A biological 'remnant' no more
Aug 20, 2009 |
4.9 / 5 (29) |
36
The lowly appendix, long-regarded as a useless evolutionary artifact, won newfound respect two years ago when researchers at Duke University Medical Center proposed that it actually serves a critical function. ...
Geobiologists propose that the earliest complex organisms fed by absorbing ocean buffet
Space & Earth / Earth Sciences
Aug 19, 2009 |
4.2 / 5 (6) |
0
Research at Virginia Tech has shown that the oldest complex life forms -- living in nutrient-rich oceans more than 540 million years ago - likely fed by osmosis.
Flat bacteria in nanoslits
Nanotechnology / Bio & Medicine
Aug 17, 2009 |
5 / 5 (5) |
2
It appears that bacteria can squeeze through practically anything. In extremely small nanoslits they take on a completely new flat shape. Even in this squashed form they continue to grow and divide at normal speeds. This ...
Anthrax bacteria conspire with viruses to stay alive
Aug 12, 2009 |
4.8 / 5 (5) |
6
(PhysOrg.com) -- The brute force of Bacillus anthracis, the ancient scourge that causes anthrax, can sweep through and overpower a two-ton animal in under 72 hours. But when it isn't busy claiming livestock and hu ...
Implant bacteria, beware: Researchers create nano-sized assassins
Nanotechnology / Bio & Medicine
Jun 26, 2009 |
4.9 / 5 (8) |
0
Staphylococcus epidermidis is quite an opportunist. Commonly found on human skin, the bacteria pose little danger. But S. epidermidis is a leading cause of infections in hospitals. From catheters to prosthetic ...
