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Encyclopedia > Bacterium
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Bacteria
Escherichia coli
Escherichia coli
Scientific classification
Kingdom: Bacteria
Haeckel, 1894
Phyla/Divisions

Actinobacteria
Aquificae
Bacteroidetes/Chlorobi
Chlamydiae/Verrucomicrobia
Chloroflexi
Chrysiogenetes
Cyanobacteria
Deferribacteres
Deinococcus-Thermus
Dictyoglomi
Fibrobacteres/Acidobacteria
Firmicutes
Fusobacteria
Gemmatimonadetes
Nitrospirae
Omnibacteria
Planctomycetes
Proteobacteria
Spirochaetes
Thermodesulfobacteria
Thermomicrobia
Thermotogae Download high resolution version (1024x861, 165 KB)Escherichia coli: Scanning electron micrograph of Escherichia coli, grown in culture and adhered to a cover slip. ... Binomial name Escherichia coli T. Escherich, 1885 E. coli at 10,000x magnification Escherichia coli (usually abbreviated to E. coli) is one of the main species of bacteria that live in the lower intestines of warm-blooded animals (including birds and mammals) and are necessary for the proper digestion of... Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ... Ernst Haeckel Ernst Heinrich Philipp August Haeckel (February 16, 1834 - August 8, 1919), also written von Haeckel, was a German biologist and philosopher who popularized Charles Darwins work in Germany. ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... In biology, the equivalent of a phylum in the plant or fungi kingdom is called a division. ... Orders Subclass Acidimicrobidae     Acidimicrobiales Subclass Actinobacteridae     Actinomycetales     Bifidobacteriales Subclass Coriobacteridae     Coriobacteriales Subclass Rubrobacteridae     Rubrobacterales Subclass Sphaerobacteridae     Sphaerobacterales The Actinobacteria or Actinomycetes are a group of Gram-positive bacteria. ... Familia Aquificaceae Hydrogenothermaceae The Aquificae phylum is a diverse collection of bacteria that live in harsh environmental settings. ... Classes & orders Class Bacteroides    Bacteroidales Class Flavobacteria    Flavobacteriales Class Sphingobacteria    Sphingobacteriales The phylum Bacteroidetes is composed of three large groups of bacteria. ... Genera Chlorobium Ancalochloris Chloroherpeton Clathrochloris Pelodictyon Prostheochloris The green sulfur bacteria are a family (Chlorobiaceae) of phototrophic bacteria. ... Orders / Genera Chlamydiales / Chlamidia Verrucomicrobiales / Verrucomicrobium Chlamydiae is a phylum of the bacteria kingdom. ... Genera Verrucomicrobium Prosthecobacter Akkermansia Verrucomicrobia is a recently described phylum of bacteria. ... Orders / Families / Genera Order Chloroflexales     Family Chloroflexaceae      Chloroflexus      Chloronema      Heliothrix      Roseiflexus    Family Oscillochloridaceae      Oscillochloris Order Herpetosiphonales      Herpetosiphon The Chloroflexi are a group of bacteria that produce energy through photosynthesis. ... Binomial name Chrysiogenes arsenatis Chrysiogenes arsenatis is a species of bacterium given its own phylum or division, called the Chrysiogenetes. ... Orders The taxonomy of the Cyanobacteria is currently under revision. ... Genera Deferribacter Denitrovibrio Flexistipes Geovibrio The Deferribacteraceae are a family of bacteria, given their own phylum (Deferribacteres). ... Orders & Genera Deinococcales     Deinococcus Thermales     Thermus     Meiothermus     Marinithermus     Oceanithermus     Vulcanithermus The Deinococcus-Thermus are a small group of bacteria comprised of cocci highly resistant to environmental hazards. ... Binomial name Dictyoglomus thermophilum Dictyoglomus thermophilum is a species of bacterium, given its own phylum, called the Dictyoglomi. ... Genera Acidobacterium Geothrix Holophaga Acidobacteria form a newly devised division of Bacteria. ... Classes Bacilli Clostridia Mollicutes The Firmicutes are a group of bacteria, most of which have Gram-positive stains. ... Fusobacteria contribute to several diseases, including periodontal diseases, Lemierres syndrome, and tropical skin ulcers. ... Plancomycetes are obligately aerobic aquatic bacteria [requires atmospheric oxygen for growth] and are found in field samples of brackish and marine as well as freshwater samples. ... Orders Alpha Proteobacteria    Caulobacterales - e. ... Families Brachyspiraceae Leptospiraceae Spirochaetaceae The spirochaetes are a phylum of distinctive bacteria, which have long, helically coiled cells. ... Genera Desulfotalea Desulfovirga Thermodesulfobacterium The Thermodesulfobacteria are a small group of thermophilic sulfate-reducing bacteria. ... Classes Thermomicrobia phylum is a phenotype of the green non-sulfur bacteria. ... Species Thermotoga elfii Thermotoga hypogea Thermotoga lettingae Thermotoga maritima Thermotoga naphthophila Thermotoga neapolitana Thermotoga petrophila Thermotoga subterranea Thermotoga thermarum Thermotoga are thermophile or hyperthermophile bacteria whose cell is wrapped in an outer toga membrane. ...

Bacteria (singular, bacterium) are a major group of living organisms. Most are microscopic and unicellular, with a relatively simple cell structure lacking a cell nucleus, cytoskeleton, and organelles such as mitochondria and chloroplasts. Their cell structure is further described in the article about prokaryotes, because bacteria are prokaryotes, in contrast to organisms with more complex cells, called eukaryotes. The term "bacteria" has variously applied to all prokaryotes or to a major group of them, depending on ideas about their relationships. In biology and ecology, an organism (in Greek organon = instrument) is an assembly of organs that influence each other in such a way that they function as a more or less stable whole and have properties of life. ... In cell biology, the nucleus (from Latin nucleus or nuculeus, kernel) is an organelle, found in all eukaryotic cells, which contains most of the cells genetic material. ... Mitochondrion - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... The inside of a chloroplast Chloroplasts are organelles found in plant cells and eukaryotic algae which conduct photosynthesis. ... Prokaryotes (from Old Greek pro- before + karyon nut, referring to the cell nucleus, + suffix -otos, pl. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Protista Eukaryotes (also spelled eucaryotes) are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ...


Bacteria are the most abundant of all organisms. They are ubiquitous in soil, water, and as symbionts of other organisms. Many pathogens are bacteria. Most are minute, usually only 0.5-5.0 μm in size (though two types, Thiomargarita namibiensis and Epulopiscium fishelsoni, reach 0.5 mm in diameter, and have a cell volume up to a million times that of the typical bacterium). They generally have cell walls, like plant and fungal cells, but with a very different composition (peptidoglycans). Many move around using flagella, which are different in structure from the flagella of other groups. For the heavy metal band see Soil (band) Soil is unconsolidated rock particle that lies on the surface of the earth, supporting the growth of plants, and serving as a habitat for animal life from microorganisms to small animals. ... Water (from the Old English word wæter; c. ... Common Clownfish (Amphiprion ocellaris) in their magnificent sea anemone (Heteractis magnifica) home. ... A pathogen literally birth of pain from the Greek παθογένεια) is a biological agent that can cause disease to its host. ... To help compare different orders of magnitude this page lists lengths between 1 micrometre and 10 micrometres (10-6 and 10-5 m). ... Binomial name Thiomargarita namibiensis Schulz , 1999 Thiomargarita namibiensis is the largest bacterium ever discovered, with a diameter of around 0. ... Epulopiscium fishelsoni is a bacterium with the long bacillus shape, being about 80µm across and between 200 and 700µm long; thus it is one of the largest types of bacteria. ... A cell wall is a more or less solid layer surrounding a cell. ... Divisions Land plants (embryophytes) Non-vascular plants (bryophytes) Hepatophyta - liverworts Anthocerophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants Adiantum pedatum (a fern... Divisions Chytridiomycota Zygomycota Glomeromycota Ascomycota Basidiomycota Yellow fungus For the fictional character, see Fungus the Bogeyman. ... Cells in culture, stained for keratin (red) and DNA (green) The cell is the structural and functional unit of all living organisms, sometimes called the building blocks of life. ... Peptidoglycan, also known as murein, is a substance that forms a homogeneous layer lying outside the plasma membrane in prokaryotes. ... A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ...

Contents


History and taxonomy

The first bacteria were observed by Antony van Leeuwenhoek in 1683 using a single-lens microscope of his own design. The name bacterium was introduced much later, by Ehrenberg in 1828, derived from the Greek word βακτηριον meaning "small stick". Louis Pasteur (1822-1895) and Robert Koch (1843-1910) described the role of bacteria as conveyors and causes of disease or pathogens. Anton von Leeuwenhoek Anton van Leeuwenhoek (October 24, 1632 _ August 26, 1723) was a tradesman and scientist from Delft, in the Netherlands. ... Events June 6 - The Ashmolean Museum opens as the worlds first university museum. ... Christian Gottfried Ehrenberg (April 19, 1795 – June 27, 1876), German naturalist, zoologist, comparative anatomist and microscopist, was one of the most famous and productive scientists of his time. ... 1828 was a leap year starting on Tuesday (see link for calendar). ... The Greek language (Greek Ελληνικά, IPA // – Hellenic) is an Indo-European language with a documented history of some 3,000 years. ... Louis Pasteur (December 27, 1822 – September 28, 1895) was a French microbiologist and chemist. ... For the American lobbyist, see Bobby Koch. ... A pathogen literally birth of pain from the Greek παθογένεια) is a biological agent that can cause disease to its host. ...


Originally the bacteria were considered microscopic fungi (called Schizomycetes), except for the photosynthetic cyanobacteria, which were considered a group of algae (called Cyanophyta or blue-green algae). It was only with the study of detailed cell structure that it was realized they formed a fundamental group, separate from the other organisms. In 1956 Copeland gave them their own kingdom Mychota, later renamed Monera, Prokaryota, or Bacteria. During the 1960s the concept was refined and bacteria (now including cyanobacteria) were recognized as one of two major divisions of the living world, together with the eukaryotes. Eukaryotes were generally believed to have evolved from bacteria, later from assemblies of bacteria. Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota The Fungi (singular: fungus) are a large group of organisms ranked as a kingdom within the Domain Eukaryota. ... Orders The taxonomy of the Cyanobacteria is currently under revision. ... The algae (singular alga) comprise several different groups of living things that produce energy through photosynthesis. ... Cyanobacteria (Greek: cyanos = blue) are a phylum of aquatic bacteria that obtain their energy through photosynthesis. ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... Charles Darwin, father of the theory of evolution by natural selection. ...


The advent of molecular systematics challenged this view. In 1977, Woese divided the prokaryotes into two groups based on 16S rRNA sequences, called the kingdoms Eubacteria and Archaebacteria. He argued that each of these and the eukaryotes all evolved separately and in 1990 emphasized this by promoting them to domains, which were renamed the Bacteria, Archaea, and Eucarya. This redefinition has generally been accepted by molecular biologists but criticized by some others, who maintain that he over-emphasized a few genetic differences and that both archaebacteria and eukaryotes probably developed from within the eubacteria. Molecular systematics is a product of the traditional field of systematics and the growing field of bioinformatics. ... Carl Woese (born July 15, 1928) is an American microbiologist famous for revolutionizing biological taxonomy. ... A non-coding RNA (ncRNA) is any RNA molecule that functions without being translated into a protein. ... Phyla / Classes Phylum Crenarchaeota Phylum Euryarchaeota     Halobacteria     Methanobacteria     Methanococci     Methanopyri     Archaeoglobi     Thermoplasmata     Thermococci Phylum Korarchaeota Phylum Nanoarchaeota The Archaea are a major group of prokaryotes. ... The three-domain system is a biological classification introduced by Carl Woese in 1990 that emphasizes his separation of prokaryotes into two groups, originally called Eubacteria and Archaebacteria. ... Phyla / Classes Phylum Crenarchaeota Phylum Euryarchaeota     Halobacteria     Methanobacteria     Methanococci     Methanopyri     Archaeoglobi     Thermoplasmata     Thermococci Phylum Korarchaeota Phylum Nanoarchaeota The Archaea are a major group of prokaryotes. ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ...


Single gene sequencing for systematics has led to whole genome sequencing, currently 212 bacterial genomes have been completed with 379 partially completed [1]. In genetics and biochemistry, sequencing means to determine the primary structure (or primary sequence) of an unbranched biopolymer. ... In genetics and biochemistry, sequencing means to determine the primary structure (or primary sequence) of an unbranched biopolymer. ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ...


Reproduction

Bacteria reproduce only asexually, not sexually. Specifically they reproduce by binary fission, or simple cell division. During this process, one cell divides into two daughter cells with the development of a transverse cell wall. Reproduction is the biological process by which new individual organisms are produced. ... Asexual reproduction the simplest form of reproduction and does not involve meiosis, gamete formation, or fertilization. ... Genetic recombination is the process by which the combination of genes in an organisms offspring becomes different from the combination of genes in that organism. ... Binary fission Binary fission is the asexual reproductive process used by most prokaryotes, which results in the reproduction of a living cell by division into two equal, or near equal, parts. ...


However, independent of sexual reproduction, genetic variations can occur within individual cells through recombinant events such as mutation (random genetic change within a cell's own genetic code). Similar to more complex organisms, bacteria also have mechanisms for exchanging genetic material. Although not equivalent to sexual reproduction, the end result is that a bacterium contains a combination of traits from two different parental cells. Three different modes of exchange have thus far been identified in bacteria: Recombinant proteins are proteins that are produced by different genetically modified organisms following insertion of the relevant DNA into their genome. ... Mutations are permanent, sometimes transmissible (if the change is to a germ cell) changes to the genetic material (usually DNA or RNA) of a cell. ...

  1. transformation (the transfer of naked DNA from one bacterial cell to another in solution, this can include dead bacteria),
  2. transduction (the transfer of viral, bacterial, or both bacterial and viral DNA from one cell to another via bacteriophage) and;
  3. bacterial conjugation (the transfer of DNA from one bacterial cell to another via a special protein structure called a conjugation pilus).

Bacteria, having acquired DNA from any of these events, can then undergo fission and pass the recombined genome to new progeny cells. Many bacteria harbor plasmids that contain extrachromosomal DNA. Under favourable conditions, bacteria may form aggregates visible to the naked eye, such as bacterial mats. Transformation is the genetic alteration of a cell resulting from the introduction, uptake and expression of foreign genetic material (DNA or RNA). ... Transduction is the process in which DNA is moved from one bacterium to another. ... Bacterial conjugation is the often regarded as the bacterial equivalent of sexual reproduction or mating; however it is not actually sexual as it does not involve the fusing of gametes and the creation of a zygote, it is merely the exchange of genetic information. ... Categories: Cell biology stubs | Cell biology ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... Figure 1 : Schematic drawing of a bacterium with plasmids enclosed. ... Bacterial lawn is a used by biologists to describe the appearance of bacterial colonies when all the individual colonies on a petri-dish merge together to form a mat of bacteria. ...


Metabolisms

Bacteria show a wide variety of different metabolisms and can accordingly be classified into primary nutritional groups. Heterotrophs depend on an organic source of carbon, while autotrophs are able to synthesize organic compounds from carbon dioxide and water. Autotrophs that obtain energy by oxidizing chemical compounds are called chemotrophs, and those that obtain their energy from light, via photosynthesis, are called phototrophs. There are many variations on this terminology such as chemoautotrophs and photosynthetic autotrophs and so on. In addition, bacteria are distinguished based on the source of reducing equivalents they are using. Those using inorganic compounds (e. g. water, hydrogen, sulfide or ammonia) for this purpose are called lithotrophs and others needing organic compounds (e. g. sugars or organic acids) and are called organotrophs. The metabolic modes of energy metabolism (phototrophy or chemotrophy), reducing equivalent sources (lithotrophy or organotrophy) and carbon sources (autotrophy or heterotrophy) can be combined differently in any single microorganism, and even shifting between different modes frequently occurs in many species. Santorio Santorio (1561-1636) in his steelyard balance, from Ars de statica medecina, first published 1614 Metabolism (from μεταβολισμος (metabolismos), the Greek word for change, or overthrow (Etymonline)), is the biochemical modification of chemical compounds in living organisms and cells. ... An organism may be placed into one each of the three pairs of major nutritional groups based on their carbon, energy, and electron sources. ... A heterotroph (Greek heteron = (an)other and trophe = nutrition) is an organism that requires organic substrates to get its carbon for growth and development. ... An autotroph (in Greek eauton = self and trophe = nutrition) is an organism that produces organic compounds from carbon dioxide as a carbon source, using either light or reactions of inorganic chemical compounds as a source of energy. ... Chemotrophs are organisms that obtain food (and therefore energy) from breaking down chemicals in their environments. ... Leaf. ... Phototrophs or photoautotrophs are photosynthetic algae, fungi, bacteria and cyanobacteria which build up carbon dioxide and water into organic cell materials using energy from sunlight. ... Inorganic chemistry is the branch of chemistry concerned with the properties and reactions of inorganic compounds. ...


The photolithoautotrophs include the cyanobacteria, which are some of the oldest organisms known from the fossil record and probably played an important role in creating the Earth's oxygen atmosphere. They apparently pioneered the use of water as (lithotrophic) electron source and were the first to use the photosynthetic water splitting apparatus. Other photosynthetic bacteria use different electron sources and therefore do not produce oxygen. These anoxygenic phototrophs fall into four phylogenetic groups: the green sulfur bacteria, green non-sulfur bacteria, purple bacteria, and heliobacteria. Orders The taxonomy of the Cyanobacteria is currently under revision. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Water splitting is the general term for a chemical reaction in which water is converted into oxygen and hydrogen. ... Green sulfur bacteria - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Orders / Families / Genera Order Chloroflexales     Family Chloroflexaceae      Chloroflexus      Chloronema      Heliothrix      Roseiflexus    Family Oscillochloridaceae      Oscillochloris Order Herpetosiphonales      Herpetosiphon The Chloroflexi are a group of bacteria that produce energy through photosynthesis. ... Purple bacteria are proteobacteria that are phototrophic, i. ... Genera Heliobacterium Heliobacillus Heliophilum Heliorestis The heliobacteria are a small family of bacteria that produce energy through photosynthesis. ...


Other nutritional requirements include nitrogen, sulfur, phosphorus, vitamins and metallic elements such as sodium, potassium, calcium, magnesium, manganese, iron, zinc, cobalt, copper and nickel for normal growth. For some species, additional trace elements such as selenium, tungsten, vanadium or boron are needed. General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Atomic mass 32. ... This article is about the chemical element. ... A vitamin is an organic molecule whose insufficiency in the diet can result in disease. ... For alternative meanings see metal (disambiguation). ... General Name, Symbol, Number sodium, Na, 11 Chemical series alkali metals Group, Period, Block 1, 3, s Appearance silvery white Atomic mass 22. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Atomic mass 39. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white Atomic mass 24. ... General Name, Symbol, Number manganese, Mn, 25 Chemical series transition metals Group, Period, Block 7, 4, d Appearance silvery metallic Atomic mass 54. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... General Name, Symbol, Number zinc, Zn, 30 Chemical series transition metals Group, Period, Block 12, 4, d Appearance bluish pale gray Atomic mass 65. ... This article is on the periodic element. ... General Name, Symbol, Number copper, Cu, 29 Chemical series transition metals Group, Period, Block 11, 4, d Appearance copper, metallic Atomic mass 63. ... General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic Atomic mass 58. ... General Name, Symbol, Number selenium, Se, 34 Chemical series nonmetals Group, Period, Block 16, 4, p Appearance gray, metallic luster Atomic mass 78. ... General Name, Symbol, Number tungsten, W, 74 Chemical series transition metals Group, Period, Block 6, 6, d Appearance grayish white, lustrous Atomic mass 183. ... General Name, Symbol, Number vanadium, V, 23 Chemical series transition metals Group, Period, Block 5, 4, d Appearance silvery gray metallic Atomic mass 50. ... General Name, Symbol, Number boron, B, 5 Chemical series metalloids Group, Period, Block 13, 2, p Appearance black Atomic mass 10. ...


Based on their response to oxygen, most bacteria can be placed into one of three groups: Some bacteria can grow only in the presence of oxygen and are called aerobes; others can grow only in the absence of oxygen and are called anaerobes; and some can grow in the presence or absence of oxygen and are called facultative anaerobes. Bacteria that do not utilize oxygen for respiration but still grow in its presence are called aerotolerant. Bacteria also thrive in environments that are considered extreme for mankind. These organisms are called extremophiles. Some bacteria inhabit hot springs and are called thermophiles; others inhabit highly saltine lakes and are called halophiles; yet others inhabit acidic or alkaline environments and are called acidophiles and alkaliphiles, respectively; and still others inhabit alpine glaciers and are called psychrophiles. An aerobic organism or aerobe is an organism that has an oxygen based metabolism. ... An anaerobic organism or anaerobe is any organism that does not require oxygen. ... A facultative anaerobe is an organism that makes ATP by aerobic respiration if oxygen is present but that switches to fermentation under anaerobic conditions. ... An extremophile is an organism, usually unicellular, which thrives in or requires extreme conditions. ... Thermophiles produce some of the bright colors of Grand Prismatic Spring, Yellowstone National Park A thermophile is an organism – a type of extremophile – which thrives at relatively high temperatures, up to about 60 °C. Many thermophiles are archaea. ... Halophiles are extremophiles that thrive in environments with very high concentrations of salt (at least 0. ... In databases, ACID stands for Atomicity, Consistency, Isolation, and Durability. ... The common (Arrhenius) definition of a base is a chemical compound that either donates hydroxide ions or absorbs hydrogen ions when dissolved in water. ... Alkaliphiles are microbes classified as extremophiles that thrive in alkaline environments with a pH of 9 to 11 such as soda lakes and carbonate-rich soils. ... A psychrophile is a type of extremophilic organism which thrives at what is considered to be unusually cold temperatures. ...


Movement

Motile bacteria can move about, either using flagella, bacterial gliding, or changes of buoyancy. A unique group of bacteria, the spirochaetes, have structures similar to flagella, called axial filaments, between two membranes in the periplasmic space. They have a distinctive helical body that twists about as it moves. A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ... Bacterial gliding is a process whereby a bacterium can move under its own power. ... Families Brachyspiraceae Leptospiraceae Spirochaetaceae The spirochaetes are a phylum of distinctive bacteria, which have long, helically coiled cells. ... A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ... A helix (pl: helices), from the Greek word έλικας/έλιξ, is a twisted shape like a spring, screw or a spiral staircase. ...


Bacterial flagella are arranged in many different ways. Bacteria can have a single polar flagellum at one end of a cell, clusters of many flagella at one end or flagella scattered all over the cell, as with Peritrichous. Many bacteria (such as E.coli) have two distinct modes of movement: forward movement (swimming) and tumbling. The tumbling allows them to reorient and introduces an important element of randomness in their forward movement. (see external links below for link to videos). A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ... In ordinary language, the word random is used to express apparent lack of purpose or cause. ...


Motile bacteria are attracted or repelled by certain stimuli, behaviors called taxes - for instance, chemotaxis, phototaxis, mechanotaxis and magnetotaxis (Italian). In one peculiar group, the myxobacteria, individual bacteria attract to form swarms and may differentiate to form fruiting bodies. The myxobacteria move only when on solid surfaces, unlike E. coli which is motile in liquid or solid media. A stimulus is the following: In physiology, a stimulus (physiology) is something external that elicits or influences a physiological or psychological activity or response. ... Chemotaxis is the phenomenon in which bodily cells, bacteria, and other single-celled or multicellular organisms direct their movements according to certain chemicals in their environment. ... Phototaxis, a phototropism, occurs when a whole organism moves in response to the stimulus light. ... Mechanotaxis is the directed movement of cell motility or outgrowth, e. ... Families & Genera Archangiaceae    Archangium Cystobacteraceae    Cystobacter    Melittangium    Stigmatella Myxoccaceae    Myxococcus    Angiococcus Polyangiaceae    Chondromyces    Nannocystis    Polyangium The myxobacteria are a group of bacteria that predominantly live in the soil. ... Families & Genera Archangiaceae    Archangium Cystobacteraceae    Cystobacter    Melittangium    Stigmatella Myxoccaceae    Myxococcus    Angiococcus Polyangiaceae    Chondromyces    Nannocystis    Polyangium The myxobacteria are a group of bacteria that predominantly live in the soil. ...


Groups and identification

Bacteria come in a wide variety of shapes:A. Rod-shaped B. Round-shaped or spherical. C. Round-shaped in clusters. D. Round-shaped in twos. E. Spiral-shaped. F. Comma-shaped.
Bacteria come in a wide variety of shapes:
A. Rod-shaped
B. Round-shaped or spherical.
C. Round-shaped in clusters.
D. Round-shaped in twos.
E. Spiral-shaped.
F. Comma-shaped.
Phylogenetic Tree of Bacteria
Phylogenetic Tree of Bacteria


Bacteria come in a variety of different shapes. Most are rod-shaped, sphere-shaped, or helix-shaped; these are respectively referred to as bacilli, cocci, and spirillum. An additional group, vibrios, are comma-shaped. Shape is no longer considered a defining factor in the classification of bacteria, but many genera are named for their shape (e.g. Bacillus, Streptococcus, Staphylococcus) and it is an important part in their identification. from Nupedia article on bacteria _ see http://www. ... Download high resolution version (925x667, 54 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (925x667, 54 KB) Wikipedia does not have an article with this exact name. ... Species Bacillus anthracis Bacillus cereus Bacillus coagulans Bacillus natto Bacillus subtilis Bacillus thuringiensis etc. ... coccus (plural - cocci) are any spherical or near spherical bacteria. ... Vibrio is a genus of bacteria, included in the gamma subgroup of the Proteobacteria. ... Species Bacillus anthracis Bacillus cereus Bacillus coagulans Bacillus natto Bacillus subtilis Bacillus thuringiensis etc. ... Species S. faecalis S. pneumoniae S. pyogenes S. suis S. viridans Streptococcus is a genus of spherical, Gram-positive bacteria of the phylum Firmicutes. ... Species S. aureus S. haemolyticus S. lugdunensis S. saprophyticus Staphylococcus (in Greek staphyle means bunch of grapes and coccos means granule) is a genus of gram-positive bacteria. ...


Another important tool is Gram staining, named after Hans Christian Gram who developed the technique. This separates bacteria into two groups, based on the composition of their cell wall. The first formal grouping of bacteria into phyla was based largely on this test: Gram staining is a method for staining samples of bacteria that differentiates between the two main types of bacterial cell wall. ... Hans Christian Joachim Gram (September 13, 1853 - November 14, 1928) was a Danish bacteriologist. ...

  • Gracilicutes - bacteria with a second cell membrane containing lipids, giving them Gram-negative stains
  • Firmicutes - bacteria with a single membrane and thick peptidoglycan wall, giving them Gram-positive stains
  • Mollicutes - bacteria with no second membrane or wall, giving them Gram-negative stains

The archeabacteria were originally included as the Mendosicutes. As given, these phyla are no longer believed to represent monophyletic groups. The Gracilicutes have been divided into many different phyla. Most gram-positive bacteria are placed in the phyla Firmicutes and Actinobacteria, which are closely related. However, the Firmicutes have been redefined to include the mycoplasmas (Mollicutes) and certain Gram-negative bacteria. Figure 1: Structure of a Lipid. ... Bacteria that are Gram-negative are not stained dark blue or violet by Gram staining, in contrast to Gram-positive bacteria. ... Peptidoglycan, also known as murein, is a substance that forms a homogeneous layer lying outside the plasma membrane in prokaryotes. ... Gram-positive bacteria are those that are stained dark blue or violet by gram staining, in contrast to gram-negative bacteria, which are not affected by the stain. ... Bacteria that are Gram-negative are not stained dark blue or violet by Gram staining, in contrast to Gram-positive bacteria. ... Classes Bacilli Clostridia Mollicutes The Firmicutes are a group of bacteria, most of which have Gram-positive stains. ... Orders Subclass Acidimicrobidae     Acidimicrobiales Subclass Actinobacteridae     Actinomycetales     Bifidobacteriales Subclass Coriobacteridae     Coriobacteriales Subclass Rubrobacteridae     Rubrobacterales Subclass Sphaerobacteridae     Sphaerobacterales The Actinobacteria or Actinomycetes are a group of Gram-positive bacteria. ... Species M. genitalium M. hominis M. pneumoniae etc. ...


Benefits and dangers

Bacteria are both harmful and useful to the environment, and animals, including humans. The role of bacteria in disease and infection is important. Some bacteria act as pathogens and cause tetanus, typhoid fever, pneumonia, syphilis, cholera, foodborne illness and tuberculosis. Sepsis, a systemic infectious syndrome characterized by shock and massive vasodilation, or localized infection, can be caused by bacteria such as streptococcus, staphylococcus, or many gram-negative bacteria. Some bacterial infections can spread throughout the host's body and become systemic. In plants, bacteria cause leaf spot, fireblight, and wilts. The mode of infection includes contact, air, food, water, and insect-borne microorganisms. The hosts infected with the pathogens may be treated with antibiotics, which can be classified as bacteriocidal and bacteriostatic, which at concentrations that can be reached in bodily fluids either kill bacteria or hamper their growth, respectively. Antiseptic measures may be taken to prevent infection by bacteria, for example, prior to cutting the skin during surgery or swabbing skin with alcohol when piercing the skin with the needle of a syringe. Sterilization of surgical and dental instruments is done to make them sterile or pathogen-free to prevent contamination and infection by bacteria. Sanitizers and disinfectants are used to kill bacteria or other pathogens to prevent contamination and risk of infection. Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria Placozoa Subregnum Bilateria  Acoelomorpha  Orthonectida  Rhombozoa  Myxozoa  Superphylum Deuterostomia     Chordata (vertebrates, etc. ... Binomial name Homo sapiens Linnaeus, 1758 Subspecies Homo sapiens idaltu (extinct) Homo sapiens sapiens Human beings define themselves in biological, social, and spiritual terms. ... A pathogen literally birth of pain from the Greek παθογένεια) is a biological agent that can cause disease to its host. ... Tetanus is a serious and often fatal disease caused by the exotoxin tetanospasmin which is produced by the Gram-positive, anaerobic bacterium Clostridium tetani. ... This is about the disease typhoid fever. ... Pneumonia is an inflammation of the lung. ... Depression-era U.S. poster advocating early syphilis treatment Syphilis (historically called lues) is a sexually transmitted disease (STD) that is caused by a spirochaete bacterium, Treponema pallidum. ... Distribution of cholera Cholera (also called Asiatic cholera) is an infectious disease of the gastrointestinal tract caused by the Vibrio cholerae bacterium. ... Foodborne illness or food poisoning is caused by consuming food contaminated with pathogenic bacteria, toxins, viruses, prions or parasites. ... Tuberculous lungs show up on an X-ray image Tuberculosis is an infection with the bacterium Mycobacterium tuberculosis, which most commonly affects the lungs (pulmonary TB) but can also affect the central nervous system (meningitis), lymphatic system, circulatory system (miliary TB), genitourinary system, bones and joints. ... Sepsis (in Greek Σήψις, putrefaction) is a serious medical condition caused by a severe infection leading to a systemic inflammatory response. ... Species S. faecalis S. pneumoniae S. pyogenes S. suis S. viridans Streptococcus is a genus of spherical, Gram-positive bacteria of the phylum Firmicutes. ... Species S. aureus S. haemolyticus S. lugdunensis S. saprophyticus Staphylococcus (in Greek staphyle means bunch of grapes and coccos means granule) is a genus of gram-positive bacteria. ... Divisions Land plants (embryophytes) Non-vascular plants (bryophytes) Hepatophyta - liverworts Anthocerophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants Adiantum pedatum (a fern... Leaf Spot - A cosmetic disease of oaks and elms. ... Binomial name Erwinia amylovora The causal pathogen is Erwinia amylovora, a Gram-negative bacterium in the family Enterobacteriaceae. ... When bacteria or fungi clog a plants water-conducting or vascular system, they can cause permanent wilting and death. ... An antibiotic is a drug that kills or slows the growth of bacteria. ... A bacteriocide or bactericide is a substance that kills bacteria and, preferably, nothing else. ... Bacteriostatic antibiotics hamper the growth of bacteria by interfering with bacteria protein production, interfering with bacteria DNA production interfering with bacteria cellular metabolism Bacteriostatic antibiotics inhibit growth and repoduction of the bacteria, though do not kill it, while bactericidal antibiotics kill bacteria. ... An antiseptic is a substance that kills or prevents the growth and reproduction of various microorganisms, including bacteria, fungi, protozoa, and viruses on the external surfaces of the body. ... Sterilization (or Sterilisation) is the elimination of all transmissible agents (such as bacteria, prions and viruses) from a surface or piece of equipment. ... Disinfection The destruction of pathogenic and other kinds of microorganisms by physical or chemical means Disinfectants are chemical substances used to kill viruses and microbes (germs), such as bacteria and fungi. ...


In soil, microorganisms help in the transformation of nitrogen to ammonia with enzymes secreted by these microbes, which reside in the rhizosphere (a zone that includes the root surface and the soil that adheres to the root after gentle shaking). Some bacteria are able to use molecular nitrogen as their source of nitrogen, converting it to nitrogenous compounds, a process known as nitrogen fixation. Many other bacteria are found as symbionts in humans and other organisms. For example, their presence in the large intestine can help prevent the growth of potentially harmful microbes. Rhizosphere, the zone that surrounds the roots of plants. ... Nitrogen fixation is the process by which nitrogen is taken from its relatively inert molecular form (N2) in the atmosphere and converted into nitrogen compounds useful for other chemical processes (such as, notably, ammonia, nitrate and nitrogen dioxide). ... Common Clownfish (Amphiprion ocellaris) in their Magnificent Sea Anemone (Heteractis magnifica) home. ... The human body contains a large number of bacteria, most of them performing tasks that are useful or even essential to human survival. ...


The ability of bacteria to degrade a variety of organic compounds is remarkable. Highly specialized groups of microorganisms play important roles in the mineralization of specific classes of organic compounds. For example, the decomposition of cellulose, which is one of the most abundant constituents of plant tissues, is mainly brought about by aerobic bacteria that belong to the genus Cytophaga. This ability has also been utilized by humans for industrial uses and for bioremediation. Bacteria capable of digesting the hydrocarbons in petroleum are often used to clean up oil spills. Some beaches in Prince William Sound were fertilized in an attempt to facilitate the growth of such bacteria after the infamous 1989 Exxon Valdez oil spill. These efforts were effective on beaches that were not too thickly covered in oil. Cellulose (C6H10O5)n is a long-chain polymer polysaccharide carbohydrate, of beta-glucose. ... Bioremediation can be defined as any process that uses microorganisms or their enzymes to return the environment altered by contaminants to its original condition. ... In chemistry, a hydrocarbon is a cleaning solution consisting only of carbon (C) and hydrogen (H). ... Nodding donkey pumping an oil well near Sarnia, Ontario, 2001 Petroleum (from Latin petra – rock and oleum – oil), crude oil, sometimes colloquially called black gold, is a thick, dark brown or greenish flammable liquid, which exists in the upper strata of some areas of the Earths crust. ... Volunteers cleaning up the aftermath of the Prestige oil spill An oil spill is the release of oil (generally, petroleum) into the natural environment, usually the ocean. ... Prince William Sound, on the south coast of Alaska. ... 1989 is a common year starting on Sunday of the Gregorian calendar. ... The Exxon Valdez oil spill was the most devastating domestic oil spill in the United States. ...


Bacteria, often in combination with yeasts and molds, are used in the preparation of fermented foods such as cheese, pickles, soy sauce, sauerkraut, vinegar, wine, and yogurt. Using biotechnology techniques, bacteria can be bioengineered for the production of therapeutic drugs, such as insulin, or for the bioremediation of toxic wastes. Yeasts constitute a group of single-celled (unicellular) fungi, a few species of which are commonly used to leaven bread and ferment alcoholic beverages. ... Moldy cream cheese Molds (British English: moulds) are various fungi that cover surfaces as fluffy mycelium and usually produce masses of asexual, sometimes sexual spores. ... In its strictest sense fermentation (scientifically called zymosis) is the energy-yielding anaerobic metabolic breakdown of a nutrient molecule, such as glucose, without net oxidation. ... Cheese is a solid food made from the curdled milk of various animals—most commonly cows but sometimes goats, sheep, reindeer, and water buffalo. ... Pickling is the process of preparing a food by soaking and storing it in a brine (salt) or vinegar solution, a process which can preserve otherwise perishable foods for months. ... Soy sauce (US) or soya sauce (UK) is a fermented sauce made from soybeans (soya beans), roasted grain, water and sea salt (US will use salt unless otherwise stated). ... Sauerkraut   listen? is finely sliced white cabbage fermented by Lactobacillus bacteria. ... The vinegar in these bottles is infused with oregano. ... A glass of red wine Wine display at the Mt Markey Winery This article is about the beverage. ... Yoghurt Yoghurt or yogurt, less commonly yoghourt or yogourt, is a dairy product produced by bacterial fermentation of milk. ... Biotechnology is technology based on biology, especially when used in agriculture, food science, and medicine. ... Biological engineering (a. ... The structure of insulin Red: carbon; green: oxygen; blue: nitrogen; pink: sulfur. ... Bioremediation can be defined as any process that uses microorganisms or their enzymes to return the environment altered by contaminants to its original condition. ... Toxic waste is a waste which is toxic. ...


Miscellaneous

In terms of evolution, bacteria are thought to be very old organisms, appearing about 3.7 billion years ago.


Two organelles, mitochondria and chloroplasts, are generally believed to have been derived from endosymbiotic bacteria. See: endosymbiotic theory. Schematic of typical animal cell, showing subcellular components. ... Mitochondrion - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... The inside of a chloroplast Chloroplasts are organelles found in plant cells and eukaryotic algae which conduct photosynthesis. ... The endosymbiotic theory concerns the origins of mitochondria and chloroplasts, which are organelles of eukaryotic cells. ... The endosymbiotic theory concerns the origins of mitochondria and chloroplasts, which are organelles of eukaryotic cells. ...


Microorganisms are widely distributed and are most abundant where they have food, moisture, and the right temperature for their multiplication and growth. They can be carried by air currents from one place to another. The human body is home to billions of microorganisms; they can be found on skin surfaces, in the intestinal tract, in the mouth, nose, and other body openings. They are in the air one breathes, the water one drinks, and the food one eats. Human anatomy or anthropotomy is a special field within anatomy. ...


The great antiquity of the bacteria has enabled them to evolve a great deal of genetic diversity. They are far more diverse than, say, the mammals or insects. For instance, the genetic distance between E. coli and Thermus aquaticus is greater than the distance between humans and oak trees. Orders Subclass Monotremata Monotremata Subclass Marsupialia Didelphimorphia Paucituberculata Microbiotheria Dasyuromorphia Peramelemorphia Notoryctemorphia Diprotodontia Subclass Placentalia Xenarthra Dermoptera Desmostylia Scandentia Primates Rodentia Lagomorpha Insectivora Chiroptera Pholidota Carnivora Perissodactyla Artiodactyla Cetacea Afrosoricida Macroscelidea Tubulidentata Hyracoidea Proboscidea Sirenia The mammals are the class of vertebrate animals characterized by the presence of mammary glands... Classes & Orders Subclass: Apterygota Orders Archaeognatha (Bristletails) Thysanura (Silverfish) Monura - extinct Subclass: Pterygota Orders Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Diaphanopteroidea - extinct Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Infraclass: Neoptera Orders Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Dermaptera (earwigs) Plecoptera (stoneflies) Orthoptera (grasshoppers, etc) Phasmatodea (walking sticks) Embioptera (webspinners) Zoraptera... Species See List of Quercus species The term oak can be used as part of the common name of any of several hundred species of trees and shrubs in the genus Quercus, and some related genera, notably Lithocarpus. ...


See also

Bacterial growth is the process in which from a bacterial cell, two equivalent daughter cells are produced. ... Bacteriocins are proteinaceous toxins produced by bacteria to inhibit the growth of similar bacterial strain(s). ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... Structures found on meteorite fragment ALH84001 Nanobacteria (sometimes incorrectly called Nannobacteria ) are claimed to be cell walled microorganisms with a diameter well below the generally accepted lower limit (about 200 nanometres) for bacteria. ...

References

  • Some text in this entry was merged with the Nupedia article entitled Bacteria, written by Nagina Parmar; reviewed and approved by the Biology group (editor: Gaytha Langlois, lead reviewer: Gaytha Langlois, lead copyeditors: Ruth Ifcher and Jan Hogle)
  • This article contains material from the Science Primer published by the NCBI, which, as a US government publication, is in the public domain [2].

Nupedia was a Web-based encyclopedia whose articles were written by experts and licensed as free content. ... The National Center for Biotechnology Information (NCBI) is part of the US National Library of Medicine (NLM), which is a branch of the US National Institutes of Health. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ...

Further reading

  • Alcamo, I. Edward. Fundamentals of Microbiology. 5th ed. Menlo Park, California: Benjamin Cumming, 1997.
  • Atlas, Ronald M. Principles of Microbiology. St. Louis, Missouri: Mosby, 1995.
  • Holt, John.G. Bergey's Manual of Determinative Bacteriology. 9th ed. Baltimore, Maryland: Williams and Wilkins, 1994.
  • Stanier, R.Y., J. L. Ingraham, M. L. Wheelis, and P. R. Painter. General Microbiology. 5th ed. Upper Saddle River, New Jersey: Prentice Hall, 1986.
  • Hugenholtz P, Goebel BM, Pace NR. Impact of Culture-Independent Studies on the Emerging Phylogenetic View of Bacterial Diversity. J Bacteriol 1998;180:4765-4774. Fulltext / PMID 9733676.

External links


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