query: bacteria that die in the presence of oxygen are called

pos: Anaerobic organism Anaerobic organism An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It may react negatively or even die if free oxygen is present. (In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenated environment.) An anaerobic organism may be unicellular (e.g. protozoans, bacteria) or multicellular. For practical purposes, there are three categories of anaerobe: obligate anaerobes, which are harmed by the presence of oxygen; aerotolerant organisms, which cannot use oxygen for growth but tolerate its presence; and facultative anaerobes, which can grow without oxygen but use oxygen if it is present.

pos: Anaerobic organism using hydrogenosomes. Some organisms metabolise primarily using glycogen, for example the Nereid (worm)s and some polychaetes, or the juvenile form of the pork parasite "Trichinella spiralis" which causes trichinosis. Anaerobic organism An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It may react negatively or even die if free oxygen is present. (In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenated environment.) An anaerobic organism may be unicellular (e.g. protozoans, bacteria) or multicellular. For practical purposes, there are three categories of anaerobe: obligate anaerobes, which are harmed by the presence

neg: Jundiz recycling plant good fertilizer. Humus is called the "higher" decomposition of organic matter. The compost humus is used as fertilizer, both organic. Organic matter decomposes via aerobic or Anaerobic digestion means. Call "composting" aerobic cycle (high presence of oxygen) decomposition of organic matter. Called "digestion" anaerobic cycle (with no or little presence of oxygen) decomposition of organic matter. The compost is naturally obtained by decomposing aerobic (with oxygen) of organic waste and plant debris, animal excrement and slurry, through the mass reproduction of thermophilic aerobic bacteria that are present naturally in any place (later the continue fermentation the other species of bacteria,

neg: Gas-pak synthesis has never been exposed to elemental oxygen. It is colored deep blue on oxidation in presence of atmospheric oxygen in the jar, but will become colorless when oxygen is gone, and anaerobic conditions are achieved. Gas-pak Gas-pak is a method used in the production of an anaerobic environment. It is used to culture bacteria which die or fail to grow in presence of oxygen ("anaerobes"). These are commercially available, disposable sachets containing a dry powder or pellets, which, when mixed with water and kept in an appropriately sized airtight jar, produce an atmosphere free of elemental oxygen gas (O).

neg: Anaerobic infection Anaerobic infection Anaerobic infections are caused by anaerobic bacteria. Obligately anaerobic bacteria do not grow on solid media in room air (0.04% carbon dioxide and 21% oxygen); facultatively anaerobic bacteria can grow in the presence or absence of air. Microaerophilic bacteria do not grow at all aerobically or grow poorly, but grow better under 10% carbon dioxide or anaerobically. Anaerobic bacteria can be divided into strict anaerobes that can not grow in the presence of more than 0.5% oxygen and moderate anaerobic bacteria that are able of growing between 2 and 8% oxygen. Anaerobic bacteria usually do not possess catalase,

neg: Glucose the formation of lactate, the end product of fermentation in mammals, even in the presence of oxygen. This effect is called the Warburg effect. For the increased uptake of glucose in tumors various SGLT and GLUT are overly produced. In yeast, ethanol is fermented at high glucose concentrations, even in the presence of oxygen (which normally leads to respiration but not to fermentation). This effect is called the Crabtree effect. Glucose is a ubiquitous fuel in biology. It is used as an energy source in organisms, from bacteria to humans, through either aerobic respiration, anaerobic respiration (in bacteria), or fermentation.

neg: Hydrogen oxidizing bacteria Hydrogen oxidizing bacteria Hydrogen oxidizing bacteria, or sometimes "Knallgas"-bacteria, are bacteria that oxidize hydrogen as a source of energy with oxygen as final electron acceptor. See microbial metabolism (hydrogen oxidation). These bacteria include "Hydrogenobacter thermophilus", "Hydrogenovibrio marinus", and "Helicobacter pylori". There are both Gram positive and Gram negative knallgas bacteria. Most grow best under microaerophilic conditions. They do this because the hydrogenase enzyme used in hydrogen oxidation is inhibited by the presence of oxygen, but oxygen is still needed as a terminal electron acceptor. The word "Knallgas" means "oxyhydrogen" (a mixture of hydrogen and oxygen, literally "bang-gas") in Germanic languages.

neg: Sewage sludge treatment generated in this way to produce more electricity than the machines require. Aerobic digestion is a bacterial process occurring in the presence of oxygen resembling a continuation of the activated sludge process. Under aerobic conditions, bacteria rapidly consume organic matter and convert it into carbon dioxide. Once there is a lack of organic matter, bacteria die and are used as food by other bacteria. This stage of the process is known as "endogenous respiration". Solids reduction occurs in this phase. Because the aerobic digestion occurs much faster than anaerobic digestion, the capital costs of aerobic digestion are lower. However, the

neg: Environmental effects of laundry wastewater mats of larger floating plants that can produce oxygen by photosynthesis. When they die and sink to the bottom, they consume oxygen in decomposition. Bacteria thriving in this process consume oxygen. With the depletion of oxygen, fishes die and anaerobic bacteria produce methane, hydrogen sulfide and ammonia, which can destroy the ecosystem. To reduce the eutrophication caused by sodium triphosphate, there are phosphorus-free builders substitutes nowadays, such as inorganic builders zeolite A and soda ash, and organic builders like polycarboxylates, citrates et al. Environmental effects of laundry wastewater Wastewater comes out of the laundry process with additional energy (heat), lint,

neg: Sewage treatment to the environment can lead to a buildup of nutrients, called eutrophication, which can in turn encourage the overgrowth of weeds, algae, and cyanobacteria (blue-green algae). This may cause an algal bloom, a rapid growth in the population of algae. The algae numbers are unsustainable and eventually most of them die. The decomposition of the algae by bacteria uses up so much of the oxygen in the water that most or all of the animals die, which creates more organic matter for the bacteria to decompose. In addition to causing deoxygenation, some algal species produce toxins that contaminate drinking water

neg: Hypochlorite engulf viruses and bacteria in an intracellular vacuole called the phagosome, where they are digested. Part of the digestion mechanism involves an enzyme-mediated respiratory burst, which produces reactive oxygen-derived compounds, including superoxide (which is produced by NADPH oxidase). Superoxide decays to oxygen and hydrogen peroxide, which is used in a myeloperoxidase-catalysed reaction to convert chloride to hypochlorite. Low concentrations of hypochlorite were also found to interact with a microbe's heat shock proteins, stimulating their role as intra-cellular chaperone and causing the bacteria to form into clumps (much like an egg that has been boiled) that will eventually die off. The

neg: Gas-pak Gas-pak Gas-pak is a method used in the production of an anaerobic environment. It is used to culture bacteria which die or fail to grow in presence of oxygen ("anaerobes"). These are commercially available, disposable sachets containing a dry powder or pellets, which, when mixed with water and kept in an appropriately sized airtight jar, produce an atmosphere free of elemental oxygen gas (O). They are used to produce an anaerobic culture in microbiology. It is a much simpler technique than the McIntosh and Filde's anaerobic jar where one needs to pump gases in and out. The addition of a

neg: Corrosion crevice corrosion can be evaluated with ASTM standard procedures. A critical crevice corrosion temperature is commonly used to rank a material's resistance to crevice corrosion. Microbial corrosion, or commonly known as microbiologically influenced corrosion (MIC), is a corrosion caused or promoted by microorganisms, usually chemoautotrophs. It can apply to both metallic and non-metallic materials, in the presence or absence of oxygen. Sulfate-reducing bacteria are active in the absence of oxygen (anaerobic); they produce hydrogen sulfide, causing sulfide stress cracking. In the presence of oxygen (aerobic), some bacteria may directly oxidize iron to iron oxides and hydroxides, other bacteria oxidize sulfur

neg: McIntosh and Filde's anaerobic jar McIntosh and Filde's anaerobic jar McIntosh and Filde's anaerobic jar is an instrument used in the production of an anaerobic environment. This method of "anaerobiosis" as others is used to culture bacteria which die or fail to grow in presence of oxygen ("anaerobes"). The jar, about 20″×12.5″ is made up of a metal. Its parts are as follows: / of the air inside is pumped out and replaced with either unmixed Hydrogen or as a 10%CO+90%H mixture. The catalyst (Palladium) acts and the oxygen is used up in forming water with the hydrogen. The manometer registers this as a fall

neg: Nitrogen fixation many bacteria cease production of the enzyme in the presence of oxygen. Many nitrogen-fixing organisms exist only in anaerobic conditions, respiring to draw down oxygen levels, or binding the oxygen with a protein such as leghemoglobin. Diazotrophs are widespread within domain Bacteria including cyanobacteria (e.g. the highly significant "Trichodesmium" and "Cyanothece"), as well as green sulfur bacteria, Azotobacteraceae, rhizobia and "Frankia". Several obligately anaerobic bacteria fix nitrogen including many (but not all) Clostridium spp. Some Archaea also fix nitrogen, including several methanogenic taxa, which are significant contributors to nitrogen fixation in anoxic soils. Cyanobacteria inhabit nearly all illuminated environments on

neg: Aerobic digestion Aerobic digestion Aerobic digestion is a process in sewage treatment designed to reduce the volume of sewage sludge and make it suitable for subsequent use. More recently, technology has been developed that allows the treatment and reduction of other organic waste, such as food, cardboard and horticultural waste. It is a bacterial process occurring in the presence of oxygen. Bacteria rapidly consume organic matter and convert it into carbon dioxide, water and a range of lower molecular weight organic compounds. As there is no new supply of organic material from sewage, the activated sludge biota begin to die and are

neg: Pus The bacteria resist the immune response by releasing toxins called leukocidins. As the neutrophils die off from toxins and old age, they are destroyed by macrophages, forming the viscous pus. Bacteria that cause pus are called pyogenic. Although pus is normally of a whitish-yellow hue, changes in the color can be observed under certain circumstances. Pus is sometimes green because of the presence of myeloperoxidase, an intensely green antibacterial protein produced by some types of white blood cells. Green, foul-smelling pus is found in certain infections of "Pseudomonas aeruginosa". The greenish color is a result of the bacterial pigment pyocyanin

neg: Microbial corrosion Microbial corrosion Microbial corrosion, also called bacterial corrosion, bio-corrosion, microbiologically influenced corrosion, or microbially induced corrosion (MIC), is corrosion caused or promoted by microorganisms, usually chemoautotrophs. It can apply to both metals and non-metallic materials. Some sulfate-reducing bacteria produce hydrogen sulfide, which can cause sulfide stress cracking. "Acidithiobacillus" bacteria produce sulfuric acid; "Acidothiobacillus thiooxidans" frequently damages sewer pipes. "Ferrobacillus ferrooxidans" directly oxidizes iron to iron oxides and iron hydroxides; the rusticles forming on the RMS "Titanic" wreck are caused by bacterial activity. Other bacteria produce various acids, both organic and mineral, or ammonia. In presence of oxygen, aerobic bacteria like

neg: Enhanced biological phosphorus removal Enhanced biological phosphorus removal Enhanced biological phosphorus removal (EBPR) is a sewage treatment configuration applied to activated sludge systems for the removal of phosphate. The common element in EBPR implementations is the presence of an anaerobic tank (nitrate and oxygen are absent) prior to the aeration tank. Under these conditions a group of heterotrophic bacteria, called polyphosphate-accumulating organisms (PAO) are selectively enriched in the bacterial community within the activated sludge. These bacteria accumulate large quantities of polyphosphate within their cells and the removal of phosphorus is said to be "enhanced". Generally speaking, all bacteria contain a fraction (1-2%) of phosphorus

neg: Phagocyte (intracellular killing) or outside of the phagocyte (extracellular killing). When a phagocyte ingests bacteria (or any material), its oxygen consumption increases. The increase in oxygen consumption, called a respiratory burst, produces reactive oxygen-containing molecules that are anti-microbial. The oxygen compounds are toxic to both the invader and the cell itself, so they are kept in compartments inside the cell. This method of killing invading microbes by using the reactive oxygen-containing molecules is referred to as oxygen-dependent intracellular killing, of which there are two types. The first type is the oxygen-dependent production of a superoxide, which is an oxygen-rich bacteria-killing substance.

neg: McIntosh and Filde's anaerobic jar in the internal pressure of the jar. Hydrogen is pumped in to fill up the jar so that the pressure inside equals atmospheric pressure. The jar is now incubated at desired temperature settings. McIntosh and Filde's anaerobic jar McIntosh and Filde's anaerobic jar is an instrument used in the production of an anaerobic environment. This method of "anaerobiosis" as others is used to culture bacteria which die or fail to grow in presence of oxygen ("anaerobes"). The jar, about 20″×12.5″ is made up of a metal. Its parts are as follows: / of the air inside is pumped out and

neg: Magnetosome large enough that its interaction with Earth’s magnetic field overcomes the thermal forces that tend to randomize the orientation of the cell in its aqueous surroundings. Magnetotactic bacteria use aerotaxis as well. Aerotaxis is a response to changes in oxygen concentration that will favor swimming towards a zone of optimal oxygen concentration. Lakes or oceans oxygen concentration is commonly dependent on depth. If the Earth’s magnetic field has a significant downward slant, the orientation along field lines aids in the search for the optimal concentration. This process being called magneto-aerotaxis. Recent research has indicated the presence of magnetosome cells within

neg: Bioluminescent bacteria enzyme called luciferase. It is important that bio-luminescent bacteria decrease production rates of luciferase when the population is sparse in number in order to conserve energy. Thus, bacterial bioluminescence is regulated by means of chemical communication referred to as quorum sensing. Essentially, certain signaling molecules named autoinducers with specific bacterial receptors become activated when the population density of bacteria is high enough. The activation of these receptors leads to a coordinated induction of luciferase production that ultimately yields visible luminescence. The chemical reaction that is responsible for bio-luminescence is catalyzed by the enzyme luciferase. In the presence of oxygen, luciferase

neg: Bacteria compounds they use to transfer electrons. Bacteria that use inorganic compounds such as hydrogren, carbon monoxide, or ammonia as sources of electrons are called lithotrophs, while those that use organic compounds are called organotrophs. The compounds used to receive electrons are also used to classify bacteria: aerobic organisms use oxygen as the terminal electron acceptor, while anaerobic organisms use other compounds such as nitrate, sulfate, or carbon dioxide. Many bacteria get their carbon from other organic carbon, called heterotrophy. Others such as cyanobacteria and some purple bacteria are autotrophic, meaning that they obtain cellular carbon by fixing carbon dioxide. In

neg: Sourdough in a mixture of flour and water. Broadly speaking, the yeast produces gas (carbon dioxide) which leavens the dough, and the lactic acid bacteria produce lactic acid, which contributes flavor in the form of sourness. The lactic acid bacteria metabolize sugars that the yeast cannot, while the yeast metabolizes the byproducts of lactic acid fermentation. Lactic acid bacteria are aerotolerant anaerobes, which means that though they are anaerobes, they can multiply in the presence of oxygen. Hammes and Vogel in 1995 distinguished three metabolic groups of lactic acid bacteria: The phylogenetic groupings of "Lactobacillus" species have been undergoing reclassification, first

neg: Pilonidal disease to cause a pilonidal cyst; however, such an event may result in inflammation of an existing cyst. However, there are cases where this can occur months after a localized injury to the area. Some researchers have proposed that pilonidal cysts may be the result of a congenital pilonidal dimple. Excessive sweating can also contribute to the cause of a pilonidal cyst. Moisture can fill a stretched hair follicle, which helps create a low-oxygen environment that promotes the growth of anaerobic bacteria, often found in pilonidal cysts. The presence of bacteria and low oxygen levels hamper wound healing and exacerbate a

neg: Sulfur donor in chemosynthesis, a process similar to photosynthesis that produces sugars and utilizes oxygen as the electron acceptor. The photosynthetic green sulfur bacteria and purple sulfur bacteria and some lithotrophs use elemental oxygen to carry out such oxidization of hydrogen sulfide to produce elemental sulfur (S), oxidation state = 0. Primitive bacteria that live around deep ocean volcanic vents oxidize hydrogen sulfide in this way with oxygen; the giant tube worm is an example of a large organism that uses hydrogen sulfide (via bacteria) as food to be oxidized. The so-called sulfate-reducing bacteria, by contrast, "breathe sulfate" instead of oxygen.

neg: Enhanced biological phosphorus removal considerably more phosphorus is removed, compared to the relatively poor phosphorus removal in conventional activated sludge systems. Enhanced biological phosphorus removal Enhanced biological phosphorus removal (EBPR) is a sewage treatment configuration applied to activated sludge systems for the removal of phosphate. The common element in EBPR implementations is the presence of an anaerobic tank (nitrate and oxygen are absent) prior to the aeration tank. Under these conditions a group of heterotrophic bacteria, called polyphosphate-accumulating organisms (PAO) are selectively enriched in the bacterial community within the activated sludge. These bacteria accumulate large quantities of polyphosphate within their cells and the removal

neg: Phloxine Bacteria exposed to phloxine B die from oxidative damage. Phloxine B ionizes in water to become a negatively charged ion that binds to positively charged cellular components. When phloxine B is subjected to light, debromination occurs and free radicals and singlet oxygen are formed. These compounds cause irreversible damage to the bacteria, leading to growth arrest and cell death. Gram-negative bacteria are phloxine B-resistant due to the outer cell membrane that surrounds them. This polysaccharide-coated lipid bilayer creates a permeability barrier that prevents efficient uptake of the compound. Addition of EDTA, which is known to strip the lipopolysaccharides and increase

neg: Anaerobic organism or techniques such as injection of the bacteria into a dicot plant, which is an environment with limited oxygen. The GasPak System is an isolated container that achieves an anaerobic environment by the reaction of water with sodium borohydride and sodium bicarbonate tablets to produce hydrogen gas and carbon dioxide. Hydrogen then reacts with oxygen gas on a palladium catalyst to produce more water, thereby removing oxygen gas. The issue with the Gaspak method is that an adverse reaction can take place where the bacteria may die, which is why a thioglycollate medium should be used. The thioglycollate supplies a

neg: Environmental issues in Puget Sound impact levels of dissolved oxygen. Nutrients feed algae, which under the right conditions, "bloom" and then die and decompose; the entire process requires a large amount of oxygen. This decreases the oxygen in the water column, lowering the dissolved oxygen level. There are both natural and man-made sources of nutrients. The primary natural source is in ocean water that flushes Hood Canal. Man-made sources include leaking septic systems, storm water runoff, agriculture and various other sources causing nutrient pollution. The presence of nutrients leads to algae growth, which consumes oxygen when the algae die and decompose, contributing to the low

neg: Creosote enrichment depends not only on the type of bacteria enriching the environment, but also the compound that has been released from the preservative. In aerobic environments, preservative compounds are limited in the biodegradation process by the presence of free oxygen. In an aerobic environment, free oxygen comes from oxygen saturated sediments, sources of precipitation, and plume edges. The free oxygen allows for the compounds to be oxidized and decomposed into new intermediate compounds. Studies have shown that when BTEX and PAH compounds were placed in aerobic environments, the oxidation of the ring structures caused cleavage in the aromatic ring and

neg: Universal stress protein which has indirect implications on transcription within the bacteria. Some of "M. tuberculosis"' USPs are suggested to be induced by the hypoxic conditions found within the granuloma. Specifically, Rv2623, a type of USP in "M. tuberculosis", is induced by the presence of nitric oxide, reactive oxygen species and a downshift in pH. All of these conditions are suggested to be produced by the actions of macrophages which are particularly prevalent within the granuloma structures that are characteristic of TB latent infections. These conditions have been found to upregulate a particular USP gene called "rv2623", as well as an additional 50

neg: Lithotroph the power that chemolithotrophs have evolved to utilize from inorganic substrates, such as sulfur. In chemolithotrophs, the compounds - the electron donors - are oxidized in the cell, and the electrons are channeled into respiratory chains, ultimately producing ATP. The electron acceptor can be oxygen (in aerobic bacteria), but a variety of other electron acceptors, organic and inorganic, are also used by various species. Aerobic bacteria such as the nitrifying bacteria, "Nitrobacter", utilize oxygen to oxidize nitrite to nitrate. Some lithotrophs produce organic compounds from carbon dioxide in a process called chemosynthesis, much as plants do in photosynthesis. Plants use

neg: Corexit Dispersants are mixtures of surfactants and solvents that are commonly used to break up floating oil slicks into small droplets, which are submerged underwater. This reduces shoreline accumulation but increases the amount of oil underwater. This also increases the surface area of the oil and, in theory, accelerates the destruction of oil by naturally occurring bacteria. Dispersants are themselves a form of pollution that can be toxic to marine life, and the increased activity of bacteria from their presence can deplete oxygen in nearby waters, causing further harm to marine life. There are important trade-offs that must be considered in

neg: Blue cheese enzyme, rennet, plays in removing the hairy layer in the casein micelle. Rennet is an enzyme that cleaves the κ-casein off the casein micelle, thus removing the strain that occurs when the hairy layer entangles. The casein micelles are then able to aggregate together when they collide with each other, forming the curds that can then be made into blue cheese. "Penicillium roqueforti" and "Penicillium glaucum" are both molds that require the presence of oxygen to grow. Therefore, initial fermentation of the cheese is done by lactic acid bacteria. The lactic acid bacteria, however, are killed by the low pH

neg: Light-dependent reactions can also synthesize ATP by oxidative phosphorylation, in the manner of other bacteria. The electron transport chain is where the mobile electron carriers are plastoquinone and cytochrome ', while the proton pumps are NADH dehydrogenase, ' and cytochrome ". Cyanobacteria are the only bacteria that produce oxygen during photosynthesis. Earth's primordial atmosphere was anoxic. Organisms like cyanobacteria produced our present-day oxygen-containing atmosphere. The other two major groups of photosynthetic bacteria, purple bacteria and green sulfur bacteria, contain only a single photosystem and do not produce oxygen. Purple bacteria contain a single photosystem that is structurally related to PS II in

neg: Mycoplasma spumans Mycoplasma spumans Mycoplasma spumans is a species of bacteria in the genus "Mycoplasma". This genus of bacteria lacks a cell wall around their cell membrane. Without a cell wall, pathogenic species in this genus are unaffected by many antibiotics such as penicillin or other beta-lactam antibiotics that target cell wall synthesis. Mycoplasma are the smallest bacterial cells yet discovered, can survive without oxygen and are typically about 0.1 µm in diameter. The etymology of the name of the species comes from the Latiny: L. part. adj. spumans, foaming, presumably alluding to thick dark markings that suggest the presence of globules

neg: Capnophile capnophiles that are more easily identified because they are also microaerophiles, organisms that can grow in high carbon dioxide as long as a small amount of free oxygen is present, but at a dramatically reduced concentration. (In the earth's atmosphere carbon dioxide levels are approximately five hundred times lower than that of oxygen, 0.04% and 21% of the total, respectively.) Obligate anaerobes are microbes that will die in the presence of oxygen without respect to the concentration of carbon dioxide in their environment, and typically acquire energy through anaerobic respiration or fermentation. In 2004, a capnophilic bacterium was characterized that

neg: Spurious relationship determine whether a new drug kills bacteria; when the researcher applies the drug to a bacterial culture, the bacteria die. But to help in ruling out the presence of a confounding variable, another culture is subjected to conditions that are as nearly identical as possible to those facing the first-mentioned culture, but the second culture is not subjected to the drug. If there is an unseen confounding factor in those conditions, this control culture will die as well, so that no conclusion of efficacy of the drug can be drawn from the results of the first culture. On the other

neg: Hypoxia (environmental) meters below the surface. Oxygen depletion can result from a number of natural factors, but is most often a concern as a consequence of pollution and eutrophication in which plant nutrients enter a river, lake, or ocean, and phytoplankton blooms are encouraged. While phytoplankton, through photosynthesis, will raise DO saturation during daylight hours, the dense population of a bloom reduces DO saturation during the night by respiration. When phytoplankton cells die, they sink towards the bottom and are decomposed by bacteria, a process that further reduces DO in the water column. If oxygen depletion progresses to hypoxia, fish kills can

neg: Biosignature isotopic compositions of carbon, nitrogen and hydrogen in organic matter; (c) multiple sulfur and oxygen isotope ratios of minerals; and (d) abundance relationships and isotopic compositions of redox sensitive metals (e.g., Fe, Mo, Cr, and rare earth elements). For example, the particular fatty acids measured in a sample can indicate which types of bacteria and archaea live in that environment. Another example are the long-chain fatty alcohols with more than 23 atoms that are produced by planktonic bacteria. When used in this sense, geochemists often prefer the term biomarker. Another example is the presence of straight-chain lipids in the form

neg: Squalene-hopene cyclase in certain bacteria in the presence of hot or acidic environments. Squalene-hopene cyclase is found in a large number of bacteria but is most readily isolated from the thermophilic bacterium "Alicyclobacillus acidocaldarius". It catalyses the conversion of the acyclic molecule of squalene into the pentacyclic triterpenes of hopene and hopanol. Squalene-hopene cyclase is thought to be an evolutionary progenitor of many classes of eukaryotic and prokaryotic sterol cyclases. Oxidosqualene cyclases, which are eukaryotic analogs of SHC require oxygen for their reaction demonstrating a much later evolution when the atmosphere began accumulating oxygen. Squalene-hopene cyclase functions in a hypoxic environment suggesting

neg: Succinyl coenzyme A synthetase succinyl CoA and succinate. This is important because succinyl CoA is an intermediate necessary for porphyrin, heme, and ketone body biosynthesis. In some bacteria, the enzyme is regulated at the transcriptional level. It has been demonstrated that the gene for SCS (sucCD) is transcribed along with the gene for α-ketoglutarate dehydrogenase (sucAB) under the control of a promoter called sdhC, which is part of the succinate dehydrogenase operon. This operon is up-regulated by the presence of oxygen and responds to a variety of carbon sources. Antibacterial drugs that prevent phosphorylation of histidine, like the molecule LY26650, are potent inhibitors of

neg: Lake metabolism Lake metabolism Lake metabolism represents a lake ecosystem's balance between carbon fixation (gross primary production) and biological carbon oxidation (ecosystem respiration). Lake metabolism includes the carbon fixation and oxidation from all organism within the lake, from bacteria to fishes. Estimates of lake metabolism typically rely on the measurement of dissolved oxygen or carbon dioxide. Oxygen is produced and carbon dioxide consumed through photosynthesis and oxygen is consumed and carbon dioxide produced through respiration. Photosynthesis: formula_1 Respiration: formula_2 Photosynthesis and oxygen production only occurs in the presence of light, while the consumption of oxygen via respiration occurs in both the presence

neg: Anaerobic infection should direct the physician in the choice of the appropriate antimicrobial agents. The length of therapy generally ranges between 2 and 4 weeks, but should be individualized depending on the response. In some instances treatment may be required for as long as 6–8 weeks, but can often be shortened with proper surgical drainage. Anaerobic infection Anaerobic infections are caused by anaerobic bacteria. Obligately anaerobic bacteria do not grow on solid media in room air (0.04% carbon dioxide and 21% oxygen); facultatively anaerobic bacteria can grow in the presence or absence of air. Microaerophilic bacteria do not grow at all aerobically

neg: Lactic acid fermentation Lactic acid fermentation Lactic acid fermentation is a metabolic process by which glucose and other six-carbon sugars (also, disaccharides of six-carbon sugars, e.g. sucrose or lactose) are converted into cellular energy and the metabolite lactate, which is lactic acid in solution. It is an anaerobic fermentation reaction that occurs in some bacteria and animal cells, such as muscle cells. If oxygen is present in the cell, many organisms will bypass fermentation and undergo cellular respiration; however, facultative anaerobic organisms will both ferment and undergo respiration in the presence of oxygen. Sometimes even when oxygen is present and aerobic metabolism is

neg: Hydrothermal vent microbial communities plumes (25°C), the surfaces exposed to warm vent plumes and in symbiotic tissues within certain vent invertebrates in the vicinity of the vent. These bacteria use various forms of available sulfur (S, S, SO) in the presence of oxygen. They are the predominant population in the majority of hydrothermal vents because their source of energy is widely available, and chemosynthesis rates increase in aerobic conditions. The bacteria at hydrothermal vents are similar to the types of sulfur bacteria found in other HS-rich environments - except "Thiomicrospira" has replaced "Thiobacillus." Other common species are "Thiothrix" and "Beggiatoa," which is of particular

neg: Acetobacter Acetobacter Acetobacter is a genus of acetic acid bacteria. Acetic acid bacteria are characterized by the ability to convert ethanol to acetic acid in the presence of oxygen. Of these, the genus "Acetobacter" is distinguished by the ability to oxidize lactate and acetate into carbon dioxide and water. Bacteria of the genus "Acetobacter" have been isolated from industrial vinegar fermentation processes and are frequently used as fermentation starter cultures. In 1998, two strains of "Acetobacter" isolated from red wine and cider vinegar were named "Acetobacter oboediens" and "Acetobacter pomorum". In 2000, "Acetobacter oboediens" and "Acetobacter intermedius" were transferred to "Gluconacetobacter"

neg: Hypoxia (environmental) blooms. As these blooms are broken down by bacteria, such as "Phanerochaete chrysosprium", oxygen is depleted by the enzymes of these organisms. Phytoplankton are mostly made up of lignin and cellulose, which are broken down by enzymes present in organisms such as "P. chrysosprium", known as white-rot"." However, the breakdown of cellulose does not deplete oxygen concentration in water, whereas breakdown of lignin does. This breakdown of lignin includes an oxidative mechanism, and requires the presence of dissolved oxygen to take place by enzymes like ligninperoxidase. Other fungi such as brown-rot, soft-rot, and blue stain fungi also are necessary in

neg: Purple sulfur bacteria the light harvesting complex. When these organisms die and sink, some pigment molecules are preserved in modified form in the sediments. One carotenoid molecule produced, okenone, is diagenetically altered to the biomarker okenane. The discovery of okenane in marine sediments implies the presence of purple sulfur bacteria during the time of burial. So far, okenane has only been identified in one sedimentary outcrop from Northern Australia dating to 1640 million years ago. The authors of the study concluded that, based on the presence of purple sulfur bacteria's biomarker, the Paleoproterozoic ocean must have been anoxic and sulfidic at depth. This

neg: Blood Falls (psychrophile), and is heterotrophic, which they assigned to the genus "Marinobacter". DNA bioinformatic analysis indicated the presence of at least four gene clusters involved in secondary metabolism. Two gene clusters are related to the production of aryl polyenes, which function as antioxidants that protect the bacteria from reactive oxygen species. Another gene cluster seems to be involved in terpene biosynthesis, most likely to produce pigments. Other bacteria identified are "Thiomicrospira" sp., and "Desulfocapsa" sp. According to Mikucki "et al." (2009), the now-inaccessible subglacial pool was sealed off years ago and transformed into a kind of "time capsule", isolating the ancient

neg: Permian–Triassic extinction event anoxia precedes the extinction. Biomarkers for green sulfur bacteria, such as isorenieratane, the diagenetic product of isorenieratene, are widely used as indicators of photic zone euxinia because green sulfur bacteria require both sunlight and hydrogen sulfide to survive. Their abundance in sediments from the P-T boundary indicates hydrogen sulfide was present even in shallow waters. This spread of toxic, oxygen-depleted water would have been devastating for marine life, producing widespread die-offs. Models of ocean chemistry show that anoxia and euxinia would have been closely associated with hypercapnia (high levels of carbon dioxide). This suggests that poisoning from hydrogen sulfide, anoxia,

neg: Chronic wound coordinated healing. It has been suggested that the three fundamental factors underlying chronic wound pathogenesis are cellular and systemic changes of aging, repeated bouts of ischemia-reperfusion injury, and bacterial colonization with resulting inflammatory host response. Since more oxygen in the wound environment allows white blood cells to produce ROS to kill bacteria, patients with inadequate tissue oxygenation, for example those who suffered hypothermia during surgery, are at higher risk for infection. The host’s immune response to the presence of bacteria prolongs inflammation, delays healing, and damages tissue. Infection can lead not only to chronic wounds but also to gangrene, loss

neg: Phagocyte pus and infected sputum. Phagocytes can also kill microbes by oxygen-independent methods, but these are not as effective as the oxygen-dependent ones. There are four main types. The first uses electrically charged proteins that damage the bacterium's membrane. The second type uses lysozymes; these enzymes break down the bacterial cell wall. The third type uses lactoferrins, which are present in neutrophil granules and remove essential iron from bacteria. The fourth type uses proteases and hydrolytic enzymes; these enzymes are used to digest the proteins of destroyed bacteria. Interferon-gamma—which was once called macrophage activating factor—stimulates macrophages to produce nitric oxide. The

neg: Cyanobacteria Cyanobacteria Cyanobacteria , also known as Cyanophyta, are a phylum of bacteria that obtain their energy through photosynthesis, and are the only photosynthetic prokaryotes able to produce oxygen. The name "cyanobacteria" comes from the color of the bacteria (). Cyanobacteria, which are prokaryotes, are also called "blue-green algae", though the term "algae" in modern usage is restricted to eukaryotes. Unlike heterotrophic prokaryotes, cyanobacteria have internal membranes. These are flattened sacs called thylakoids where photosynthesis is performed. Phototrophic eukaryotes perform photosynthesis by plastids that may have their ancestry in cyanobacteria, acquired long ago via a process called endosymbiosis. These endosymbiotic cyanobacteria

neg: Scalindua phylum Planctomycetes. Anammox bacteria, including those belonging to "Ca." Scalindua, fix carbon using carbon dioxide as a carbon source. Metagenomic analysis has revealed the presence of genes responsible for the “reductive acetyl-CoA pathway (also known as the Wood-Ljungdahl pathway) which allows for the creation of the precursor molecule acetyl CoA from carbon dioxide. Ammonium and methane are known to be relatively difficult to activate with reactions catalyzed by enzymes that make use of high-potential oxygen radicals, which are unavailable to anaerobic life, leading to the assumption that both compounds were effectively inactive in low oxygen environments. Throughout the 1970s and

neg: Baltic Sea hypoxia the sediment surface. They are small and fast-growing, and can tolerate low concentrations of oxygen. When oxygen concentrations are low enough only bacteria and fungi can survive. These areas are called dead zones. In the Baltic Sea, low oxygen concentrations also reduce the ability of cod to spawn in bottom waters. Cod spawning requires both high salinity and high oxygen concentrations for cod fry to develop, conditions that are rare in the Baltic Sea today. The lack of oxygen also increases the release of phosphorus from bottom sediments. Excess phosphorus in surface waters and the lack of nitrogen stimulates the

neg: Clostridium tertium anaerobic bacteria that can tolerate oxygen and exhibit growth to some extent in the presence of oxygen. The aerotolerance of "C." "tertium" can lead to its misidentification as "Bacillus" spp. or "Lactobacillus" spp. A negative catalase test is an easy tool to differentiate "C." "tertium" from "Bacillus" spp., which are catalase positive. Also, "C." "tertium" only forms spores anaerobically, as opposed to "Bacillus" spp., which sporulates aerobically. Other distinct characteristics are its large size (1.5 x 10 micrometers)and its unusual "square" morphology on Gram stained smear. "Clostridium" "tertium" has traditionally been considered nonpathogenic, but increasingly it is being reported as

neg: Magnetotactic bacteria Magnetotactic bacteria Magnetotactic bacteria (or MTB) are a polyphyletic group of bacteria that orient themselves along the magnetic field lines of Earth's magnetic field. Discovered in 1963 by Salvatore Bellini and rediscovered in 1975 by Richard Blakmore, this alignment is believed to aid these organisms in reaching regions of optimal oxygen concentration. To perform this task, these bacteria have organelles called magnetosomes that contain magnetic crystals. The biological phenomenon of microorganisms tending to move in response to the environment's magnetic characteristics is known as magnetotaxis. (However, this term is misleading in that every other application of the term taxis involves

neg: Nitrifying bacteria nitrate by nitrite-oxidizing bacteria (NOB), represented by the "Nitrobacter" genus. Ammonia oxidation in autotrophic nitrification is a complex process that requires several enzymes, proteins and presence of oxygen. The key enzymes, necessary to obtaining energy during oxidation of ammonia to nitrite are ammonia monooxygenase (AMO) and hydroxylamine oxidoreductase (HAO). First is a transmembrane copper protein which catalyzes the oxidation of ammonia to hydroxylamine (1.1) taking two electrons directly from the quinone pool. This reaction requires O. The second step of this process has recently fallen into question. For the past few decades, the common view was that a trimeric multiheme

neg: Prevotella melaninogenica Prevotella melaninogenica Prevotella melaninogenica is a species of bacterium in the normal flora of the upper respiratory tract. It is an important human pathogen in various anaerobic infections, often mixed with other aerobic and anaerobic bacteria. "B. melaninogenicus" is an anaerobic, Gram-negative rod, named for its black colonies, and black pigment. "P. melaninogenica" are Gram-negative rod-shaped bacteria. They cannot survive in the presence of oxygen. They are not motile, and do not form spores. "P. melaninogenica" grow well on blood agar, where they form circular dark-colored colonies that darken over one to two weeks. "P. melaninogenica" was originally described as

neg: Magnetotactic bacteria to extremely large yields. Although some progress has been made, the former has not been achieved with the available pure cultures. Magnetotactic bacteria Magnetotactic bacteria (or MTB) are a polyphyletic group of bacteria that orient themselves along the magnetic field lines of Earth's magnetic field. Discovered in 1963 by Salvatore Bellini and rediscovered in 1975 by Richard Blakmore, this alignment is believed to aid these organisms in reaching regions of optimal oxygen concentration. To perform this task, these bacteria have organelles called magnetosomes that contain magnetic crystals. The biological phenomenon of microorganisms tending to move in response to the environment's

neg: Sequencing batch reactor oxygen environment, now start to use oxidized nitrogen instead of oxygen gas (as an alternate terminal electron acceptor) and convert the nitrogen to a gaseous state, as nitrogen oxides or, ideally, molecular nitrogen (dinitrogen, N) gas. This is known as denitrification. Anoxic SBR can be used for anaerobic processes, such as the removal of ammonia via Anammox, or the study of slow-growing microorganisms. In this case, the reactors are purged of oxygen by flushing with inert gas and there is no aeration. As the bacteria multiply and die, the sludge within the tank increases over time and a waste activated

neg: Acetobacter on the basis of 16S rRNA sequencing. In 2002, "Acetobacter cerevisiae" and "Acetobacter malorum" were identified by 16S rRNA sequence analysis of "Acetobacter" strains. In 2006, a strain of "Acetobacter" isolated from spoiled red wine was named "Acetobacter oeni". Acetobacter Acetobacter is a genus of acetic acid bacteria. Acetic acid bacteria are characterized by the ability to convert ethanol to acetic acid in the presence of oxygen. Of these, the genus "Acetobacter" is distinguished by the ability to oxidize lactate and acetate into carbon dioxide and water. Bacteria of the genus "Acetobacter" have been isolated from industrial vinegar fermentation processes

neg: Phosphate example, blooms in the populations of some organisms at the expense of others, and the collapse of populations deprived of resources such as oxygen (see eutrophication) can occur. In the context of pollution, phosphates are one component of total dissolved solids, a major indicator of water quality, but not all phosphorus is in a molecular form that algae can break down and consume. Calcium hydroxyapatite and calcite precipitates can be found around bacteria in alluvial topsoil. As clay minerals promote biomineralization, the presence of bacteria and clay minerals resulted in calcium hydroxyapatite and calcite precipitates. Phosphate deposits can contain significant

neg: Riftia pachyptila trophosome by Colleen Cavanaugh. The bright red color of the plume structures results from several extraordinarily complex hemoglobins, which contain up to 144 globin chains (each presumably including associated heme structures). These tube worm hemoglobins are remarkable for carrying oxygen in the presence of sulfide, without being inhibited by this molecule as hemoglobins in most other species are. Nitrate and nitrite are toxic, but nitrogen is required for biosynthetic processes. The chemosynthetic bacteria within the trophosome convert this nitrate to ammonium ions, which then are available for production of amino acids in the bacteria, which are in turn released to

neg: Innate immune system a macrophage triggers it to engulf and destroy the bacteria through the generation of a “respiratory burst”, causing the release of reactive oxygen species. Pathogens also stimulate the macrophage to produce chemokines, which summon other cells to the site of infection. Neutrophils, along with two other cell types (eosinophils and basophils; see below), are known as granulocytes due to the presence of granules in their cytoplasm, or as polymorphonuclear cells (PMNs) due to their distinctive lobed nuclei. Neutrophil granules contain a variety of toxic substances that kill or inhibit growth of bacteria and fungi. Similar to macrophages, neutrophils attack pathogens

neg: Mesoproterozoic and so on. These have real meaning for the geologist and paleontologist. For that matter, they are not completely without biological markers. There has been considerable progress in studying and identifying fossil bacteria and Eukarya. The cyanobacterium Archaeoellipsoides is one relatively common form, apparently known from several species. It is probably related to the extant Anabaena and indicates the presence of significant free oxygen. Oxygen levels also had significant effects on ocean chemistry; continental weathering rates increased and provided sulfates and nitrates as nutrients. It would be remarkable if this didn't result in new populations of both bacterial and eukaryotic

neg: Oxygen evolution Jan Ingenhousz, a Dutch physician, who showed that "restoration" of air only worked in the presence of light and green plant parts. Ingenhousz suggested in 1796 that CO (carbon dioxide) is split during photosynthesis to release oxygen, while the carbon combined with water to form carbohydrates. While this hypothesis was attractive and reasonable and thus widely accepted for a long time, it was later proven incorrect. Graduate student C.B. Van Niel at Stanford University found that purple sulfur bacteria reduce carbon to carbohydrates, but accumulate sulfur instead of releasing oxygen. He boldly proposed that, in analogy to the sulfur bacteria's

neg: Cyanobacteria polysaccharides exhibit immunomodulatory, antitumor, antithrombotic, anticoagulant, anti-mutagenic, anti-inflammatory, antimicrobial, and even antiviral activity against HIV, herpes, and hepatitis. Cyanobacteria Cyanobacteria , also known as Cyanophyta, are a phylum of bacteria that obtain their energy through photosynthesis, and are the only photosynthetic prokaryotes able to produce oxygen. The name "cyanobacteria" comes from the color of the bacteria (). Cyanobacteria, which are prokaryotes, are also called "blue-green algae", though the term "algae" in modern usage is restricted to eukaryotes. Unlike heterotrophic prokaryotes, cyanobacteria have internal membranes. These are flattened sacs called thylakoids where photosynthesis is performed. Phototrophic eukaryotes perform photosynthesis by plastids

neg: Benguela Current unit area than the global ocean average. While upwelling promotes abundant primary and secondary production in the upper parts of the water column and near the coast, deeper waters with limited oxygen exchange create hypoxic areas called oxygen minimum zones at the coastal shelf and upper coastal slope. The Benguela oxygen minimum zone starts around a depth of 100 m and is a few hundred meters thick. Bacteria that use sulpher rather than oxygen reside in the oxygen minimum zone. The most abundant fishes in the Benguela system are "Sardinops" and "Engraulis". "Sardinops ocelata" (pilchard) was intensely fished beginning in

neg: Freshwater environmental quality parameters "sewage fungus" – usually "Sphaerotilus natans". The presence of such organisms is almost always an indicator of extreme organic pollution and would be expected to be matched with low dissolved oxygen concentrations and high BOD vales. E. coli bacteria have been commonly found in recreational waters and their presence is used to indicate the presence of recent faecal contamination, but E. coli presence may not be indicative of human waste. " E. coli" are found in all warm-blooded animals. "E. coli" have also been found in fish and turtles. Enterobacteria may also persist in the environment in mud, sediments, sand

neg: Lung microbiota is possible due to the presence of nutrients, oxygen, and optimal growth temperature. There are several host-derived nutrient sources for microbial residents: secretions from airway epithelial cells (especially goblet cells), secretions from submucosal glands and transudate from plasma. Moreover, the pool of available nutrients is increased by the activities of some members of the microbiota. Macromolecular components of respiratory secretions (proteins, glycoproteins, lipids, nucleic acids) are converted to nutrients (e.g. carbohydrates, amino acids). Thus, the metabolic activity of present bacteria allow for the colonization of new species. The commensal bacteria are nonpathogenic and defend our airways against the pathogens. There

neg: Halomonas Halomonas Halomonas is a genus of halophilic (salt-tolerating) proteobacteria. It grows over the range of 5 to 25% NaCl. The type species of this genus is "Halomonas elongata". Members of "Halomonas" are Gram-negative, rod-shaped bacteria, generally 0.6-0.8 μm by 1.6-1.9 μm. They move by using flagella. They grow in the presence of oxygen, although some have been reported to be able to grow without oxygen. When grown on an agar plate, they form white/yellow colonies that turn light brown over time. "Halomonas" species have been found in a broad variety of saline environments, including estuaries, the ocean, and saline lakes.

neg: Deep-sea wood lead to the growth of many other marine bacteria including "Alphaproteobacteria", "Flavobacteria", "Actinobacteria", "Clostridia", and "Bacteroidetes". The presence of "Clostridia", obligate anaerobes suggests that the process of degrading the deep-sea wood may create oxygen-free environments for these bacteria to survive in. Many bacterial strains that were found on deep-sea wood were sulfur-reducing bacteria, meaning they obtain energy from reducing elemental sulfur, instead of traditionally using the sun for energy like almost all other organisms. Marine biologists suggest they may contribute to the break down of cellulose from the wood. The species of wood that falls to the ocean floor produces

neg: Chloroflexi (class) Chloroflexi (class) The Chloroflexia are one of six classes of bacteria in the phylum Chloroflexi, known as filamentous green non-sulfur bacteria. They produce energy from light and are named for their green pigment, usually found in photosynthetic bodies called chlorosomes. Chloroflexia are typically filamentous, and can move about through bacterial gliding. They are facultatively aerobic, but do not produce oxygen in the process of producing energy from light, or phototrophy. Additionally, Chloroflexia have a different method of phototrophy (photoheterotrophy) than true photosynthetic bacteria. Whereas most bacteria, in terms of diversity, are diderms and stain Gram negative with the exception of

neg: Chloroflexi (class) Davy and named after its pale green colour. Chloroflexi (class) The Chloroflexia are one of six classes of bacteria in the phylum Chloroflexi, known as filamentous green non-sulfur bacteria. They produce energy from light and are named for their green pigment, usually found in photosynthetic bodies called chlorosomes. Chloroflexia are typically filamentous, and can move about through bacterial gliding. They are facultatively aerobic, but do not produce oxygen in the process of producing energy from light, or phototrophy. Additionally, Chloroflexia have a different method of phototrophy (photoheterotrophy) than true photosynthetic bacteria. Whereas most bacteria, in terms of diversity, are diderms

neg: Microbial corrosion "Acidithiobacillus thiooxidans", "Thiobacillus thioparus", and "Thiobacillus concretivorus", all three widely present in the environment, are the common corrosion-causing factors resulting in biogenic sulfide corrosion. Without presence of oxygen, anaerobic bacteria, especially "Desulfovibrio" and "Desulfotomaculum", are common. "Desulfovibrio salixigens" requires at least 2.5% concentration of sodium chloride, but "D. vulgaris" and "D. desulfuricans" can grow in both fresh and salt water. "D. africanus" is another common corrosion-causing microorganism. The genus "Desulfotomaculum" comprises sulfate-reducing spore-forming bacteria; "Dtm. orientis" and "Dtm. nigrificans" are involved in corrosion processes. Sulfate-reducers require reducing environment; an electrode potential lower than -100 mV is required for them to

neg: Oxygen bacteria evolved, probably about 3.5 billion years ago. Free oxygen first appeared in significant quantities during the Paleoproterozoic eon (between 3.0 and 2.3 billion years ago). For the first billion years, any free oxygen produced by these organisms combined with dissolved iron in the oceans to form banded iron formations. When such oxygen sinks became saturated, free oxygen began to outgas from the oceans 3–2.7 billion years ago, reaching 10% of its present level around 1.7 billion years ago. The presence of large amounts of dissolved and free oxygen in the oceans and atmosphere may have driven most of the

neg: Jundiz recycling plant at the hotter and more hostile conditions of 55–60 °C, these are called thermophile.Methanogens come from the domain of archaea. This family includes species that can grow in the hostile conditions of hydrothermal vents. These species are more resistant to heat and can therefore operate at high temperatures, a property that is unique to thermophile. As with aerobic systems the bacteria in anaerobic systems the growing and reproducing microorganisms within them require a source of elemental oxygen to survive. In an anaerobic system there is an absence of gaseous oxygen. Gaseous oxygen is prevented from entering the system through physical

neg: Endospore individuals with cutaneous anthrax recovered. Had it not been for antibiotic therapy many more might have been stricken. According to WHO veterinary documents, "B. anthracis" sporulates when it sees oxygen instead of the carbon dioxide present in mammal blood; this signals to the bacteria that it has reached the end of the animal, and an inactive dispersable morphology is useful. Sporulation requires the presence of free oxygen. In the natural situation, this means the vegetative cycles occur within the low oxygen environment of the infected host and, within the host, the organism is exclusively in the vegetative form. once outside

neg: Cable bacteria Cable bacteria Cable bacteria are filamentous bacteria that conduct electricity across distances over 1 cm in sediment and groundwater aquifers. Cable bacteria couple the reduction of oxygen or nitrate at the sediment's surface to the oxidation of sulfide in the deeper, anoxic, sediment layers. Long-distance electrical conductance in sediment was first observed in 2010 as a spatial separation of sulfide oxidation and oxygen reduction in marine sediment that was interrupted and re-established at a rate faster than could be explained by chemical diffusion. It was later found that this electrical conductance could be observed across a non-conductive layer of glass

neg: Bacteriovorax stolpii genus through phylogenetic analysis. "Bacteriovorax" and "Bdellovibrio" genera share numerous morphological and lifestyle characteristics. "Bacteriovorax" and similar genera are recognized by their presence of sphingolipids, which are not widely distributed in prokaryotes. "Bacteriovorax stolpii" is known for the presence of sphinophosphonolipids in its membranes. The genome size of the "Bacteriovorax" genus has been noted from 2.0–2.6 Mb. "Bacteriovorax" is only predatory to Gram-negative bacteria, though they have been found in the gut of humans. "Bacteriovorax" and "Bdellovibrio" are approximately 0.2-0.4 x 0.5-1.4 μm, are aerobic, with oxygen as a terminal electron acceptor, and are mesophilic. They display a typical Gram-negative

neg: Comparison of anaerobic and aerobic digestion input material. When the oxygen source in an anaerobic system is derived from the organic material itself, then the 'intermediate' end products are primarily alcohols, aldehydes, and organic acids plus carbon dioxide. In the presence of specialised methanogens, the intermediates are converted to the 'final' end products of methane, carbon dioxide with trace levels of hydrogen sulfide. In an anaerobic system the majority of the chemical energy contained within the starting material is released by methanogenic bacteria as methane. In an aerobic system, such as composting, the microorganisms access free, gaseous oxygen directly from the surrounding atmosphere. The end products

neg: Magnetotaxis Brownian Motion . After orienting, the bacteria use flagella to swim along the magnetic field, towards the more favourable environment . Magnetotaxis has no impact on the average speed of the bacteria. Once these bacteria die, they are able to orient themselves to the Earth's magnetic field but they are incapable of migrating along the field . These bacteria are now simply called magnetic bacteria . Magnetic bacteria (e.g. Magnetospirillum magnetotacticum) contain internal structures known as magnetosomes which are responsible for the process of magnetotaxis. Magnetosomes contain crystals - often magnetite (Fe3O4). Some extremophile bacteria from sulfurous environments have been

neg: Photosynthesis and does not release oxygen, and seems to have evolved separately from the more common types of photosynthesis. In photosynthetic bacteria, the proteins that gather light for photosynthesis are embedded in cell membranes. In its simplest form, this involves the membrane surrounding the cell itself. However, the membrane may be tightly folded into cylindrical sheets called thylakoids, or bunched up into round vesicles called "intracytoplasmic membranes". These structures can fill most of the interior of a cell, giving the membrane a very large surface area and therefore increasing the amount of light that the bacteria can absorb. In plants and

neg: Euxinia euxinic. The basic requirements for the formation of euxinic conditions are the absence of oxygen (O), and the presence of sulfate ions (SO), organic matter (CHO), and bacteria capable of reducing sulfate to hydrogen sulfide (HS). The bacteria utilize the redox potential of sulfate as an oxidant and organic matter as a reductant to generate chemical energy through cellular respiration. The chemical species of interest can be represented via the reaction: 2CHO + SO → HS + 2HCO In the reaction above the sulfur has been reduced to form the byproduct hydrogen sulfide, the characteristic compound present in water under

neg: Nanocomposite hydrogels and improvement in electrical conductance. The presence of silver ions either stop the respiratory enzyme from transferring electrons to oxygen molecules during respiration or prevent proteins from reacting with thiol groups (-SH) on bacteria membrane, both result in the death of bacteria and microorganism without damaging mammal cells. The size of these silver nanoparticles need to be small enough to pass through the cell membrane and thus further research is required to manufacture them into appropriate sizes. Some concerns relating to hydrogels infused with nanoparticles are the chances of either bursting, or of incomplete release of drugs. Although hydrogels infused

neg: Compounds of oxygen or rust, , readily oxidise at standard conditions for temperature and pressure (STP). The surface of metals like aluminium and titanium are oxidized in the presence of air and become coated with a thin film of oxide that passivates the metal and slows further corrosion. So-called noble metals, such as gold and platinum, resist direct chemical combination with oxygen, and substances like gold(III) oxide () must be formed by an indirect route. The alkali metals and alkali earth metals all react spontaneously with oxygen when exposed to dry air to form oxides, and form hydroxides in the presence of oxygen

neg: Magnetotaxis Magnetotaxis Magnetotaxis is a process implemented by a diverse group of gram negative bacteria that involves orienting and coordinating movement in response to Earth's magnetic field . This process is mainly carried out by microaerophilic and anaerobic bacteria found in aquatic environments such as salt marshes, seawater, and freshwater lakes . By sensing the magnetic field, the bacteria are able to orient themselves towards environments with more favourable oxygen concentrations. This orientation towards more favourable oxygen concentrations allows the bacteria to reach these environments faster as opposed to if the bacteria were to move randomly to find these environments through

neg: Everglades and marl. Where there are longer hydroperiods, peat builds up over hundreds or thousands of years due to many generations of decaying plant matter. Where periphyton grows, the soil develops into marl, which is more calcitic in composition. Initial attempts at developing agriculture near Lake Okeechobee were successful, but the nutrients in the peat were rapidly removed. In a process called soil subsidence, oxidation of peat causes loss of volume. Bacteria decompose dead sawgrass slowly underwater without oxygen. When the water was drained in the 1920s and bacteria interacted with oxygen, an aerobic reaction occurred. Microorganisms degraded the peat into

neg: Whale fall be truncated. Researchers believe the presence of "Osedax" (Latin: bone-devourer) may be a contributing factor in the successional differences. Also known as zombie worms—so called because they have no eyes or mouth—they were first discovered in the deep Submarine Monterey Canyon off central California in 2002. Other examples have since been discovered off Sweden, Japan, and Antarctica. "Osedax" larvae have no digestive tract; instead they float through the oceans until they encounter a carcass. The worms then grow appendages resembling tiny trees that absorb oxygen. A root-like structure grows into the bone; these contain symbiotic bacteria which make an acid

neg: Oxygen saturation Agency has published a table of maximum equilibrium dissolved oxygen concentration versus temperature at atmospheric pressure. The optimal levels in an estuary for dissolved oxygen is higher than 6 ppm. Insufficient oxygen (environmental hypoxia), often caused by the decomposition of organic matter and/or nutrient pollution, may occur in bodies of water such as ponds and rivers, tending to suppress the presence of aerobic organisms such as fish. Deoxygenation increases the relative population of anaerobic organisms such as plants and some bacteria, resulting in fish kills and other adverse events. The net effect is to alter the balance of nature by

neg: Manganese Mn-SOD is the type of SOD present in eukaryotic mitochondria, and also in most bacteria (this fact is in keeping with the bacterial-origin theory of mitochondria). The Mn-SOD enzyme is probably one of the most ancient, for nearly all organisms living in the presence of oxygen use it to deal with the toxic effects of superoxide (), formed from the 1-electron reduction of dioxygen. The exceptions, which are all bacteria, include "Lactobacillus plantarum" and related lactobacilli, which use a different nonenzymatic mechanism with manganese (Mn) ions complexed with polyphosphate, suggesting a path of evolution for this function in aerobic life.

neg: Aerobic organism Aerotolerant organisms must continue fermentation in the presence of oxygen. A good example is the oxidation of glucose (a monosaccharide) in aerobic respiration. Oxygen is used during the oxidation of glucose and water is produced. This equation is a summary of what happens in three series of biochemical reactions: glycolysis, the Krebs cycle, and oxidative phosphorylation. Aerobic organism An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment. In contrast, an anaerobic organism (anaerobe) is any organism that does not require oxygen for growth. Some anaerobes react negatively or even die if oxygen

neg: OXO-biodegradation to degrade and then biodegrade in the open environment . These salts catalyze the abiotic degradation process so that Oxo-biodegradable plastic will degrade in the presence of oxygen much more quickly than ordinary plastic . Sunlight and heat will accelerate the process further, but no special environmental conditions are necessary . The material has then been converted into short-chain organic chemicals, such as ketones, alcohols, carboxylic acids, and low molecular mass hydrocarbon waxes. These remaining chemicals are no longer plastic and are biodegradable by bacteria, which are ubiquitous in the terrestrial and marine environments. The timescale for complete bio degradation

neg: Purple bacteria One type of purple bacteria, called purple sulfur bacteria (PSB), use sulfide or sulfur as electron donors. Another type, called purple non-sulfur bacteria, typically use hydrogen as an electron donor but can also use sulfide or organic compounds at lower concentrations compared to PSB. Purple bacteria lack external electron carriers to spontaneously reduce NAD(P) to NAD(P)H, so they must use their reduced quinones to endergonically reduce NAD(P)+. This process is driven by the proton motive force and is called reverse electron flow. Purple bacteria were the first bacteria discovered to photosynthesize without having an oxygen byproduct. Instead, their byproduct is

neg: Hood Canal of algae in the basin. When the algae die, bacteria feed and their populations explode, robbing the water of oxygen. A state of hypoxia is created. The fish kill may also be part of a natural 50-year cycle of oxygen levels in the canal, which has merely been influenced (but not controlled) by anthropogenic activity. Natural causes of hypoxia in Hood Canal include the timing of freshwater inflows, water layer stratification resulting from seasonal changes in surface temperature, and climate change. The oxygen level may also be partially due to a change in wind direction. The prevailing north wind generally