parent_taxon nitrosomonadales
A reducing agent ( also called a reductant or reducer ) is an element ( such as calcium ) or compound that loses ( or " donates ") an ___MASK83___ to another chemical species in a redox chemical reaction . Since the reducing agent is losing electrons , it is said to have been oxidized . ___MASK6___ is a genus of Gram - negative bacteria , possessing a curved - rod shape ( comma shape ), several species of which can cause foodborne infection , usually associated with eating undercooked seafood . Typically found in salt water , " ___MASK6___ " species are facultative anaerobes that test positive for oxidase and do not form spores . All members of the genus are motile and have polar flagella with sheaths . " ___MASK6___ " species typically possess two chromosomes , which is unusual for bacteria . Each chromosome has a distinct and independent origin of replication , and are conserved together over time in the genus . Recent phylogenies have been constructed based on a suite of genes ( multilocus sequence analysis ). ___MASK49___ minus is a species of " ___MASK49___ ". " ___MASK49___ minus " is associated with ___MASK81___ - bite fever . Ammonia or azane is a compound of nitrogen and hydrogen with the formula NH . The simplest pnictogen hydride , ammonia is a colourless gas with a characteristic pungent smell . It contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers . Ammonia , either directly or indirectly , is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products . The ___MASK16___ are a small order of Proteobacteria . Like all Proteobacteria , they are gram - negative . They include Nitrosomonas , Nitrosospira , Gallionella ( iron bacteria ) , and Spirillum . Members of the genus Nitrosomonas oxidize ammonia into nitrite , a process called nitrification . They are important in the nitrogen cycle . The species Spirillum minus causes Rat bite fever . Gram - negative ___MASK22___ are a group of ___MASK22___ that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation . They are characterized by their cell envelopes , which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane . ___MASK31___ is a genus of Gram - negative , nonspore forming , facultatively anaerobic , rod - shaped ___MASK22___ from the family ___MASK89___ . In those species which are inhabitants of the gastrointestinal tracts of warm - blooded animals , " ___MASK31___ " species provide a portion of the microbially derived vitamin K for their host . A number of the species of " ___MASK31___ " are pathogenic . The genus is named after Theodor Escherich , the discoverer of " ___MASK31___ coli ". ___MASK67___ is a family of ___MASK22___ . It has been described as a member of ___MASK16___ , in ___MASK100___ . In biology , an organism is any contiguous living system , such as an ___MASK88___ , ___MASK85___ , fungus , archaeon , or bacterium . All known types of organisms are capable of some degree of response to stimuli , reproduction , growth and development and homeostasis . An organism consists of one or more cells ; when it has one cell it is known as a unicellular organism ; and when it has more than one it is known as a multicellular organism . Most unicellular organisms are of microscopic scale and are thus loosely described as microorganisms . Humans are multicellular organisms composed of many trillions of cells grouped into specialized tissues and organs . Nitro compounds are organic compounds that contain one or more nitro functional groups (). The nitro group is one of the most common explosophores ( functional group that makes a compound explosive ) used globally . The nitro group is also strongly ___MASK83___ - withdrawing . Because of this property , C  H bonds alpha ( adjacent ) to the nitro group can be acidic . For similar reasons , the presence of nitro groups in aromatic compounds retards electrophilic aromatic substitution but facilitates nucleophilic aromatic substitution . Nitro groups are rarely found in nature , being almost invariably produced by nitration reactions starting with nitric acid . ___MASK93___ is a genus of rod - shaped ( ___MASK46___ ) gram - negative bacteria of the Enterobacteriaceae family . The two species of " ___MASK93___ " are " ___MASK93___ enterica " and " ___MASK93___ bongori ". " ___MASK93___ enterica " is the type species and is further divided into six subspecies that include over 2500 serotypes . ___MASK72___ is a genus of bacteria in the family Enterobacteriaceae . " ___MASK72___ " species are Gram - negative , rod - shaped bacteria , a few micrometers long and fractions of a micrometer in diameter , and are facultative anaerobes . Some members of " ___MASK72___ " are pathogenic in humans ; in particular , " Y . pestis " is the causative agent of the plague . Rodents are the natural reservoirs of " ___MASK72___ "; less frequently , other mammals serve as the host . Infection may occur either through blood ( in the case of " Y . pestis ") or in an alimentary fashion , occasionally via consumption of food products ( especially vegetables , milk - derived products , and meat ) contaminated with infected urine or feces . The term " microbiologist " comes from the Greek " mkros " meaning " small " , and " bios ", meaning " life " , combined with "- logia " meaning one who studies . A microbiologist ( from Greek ) is a biological scientist who studies microscopic life forms and processes or works in the field of microbiology . Microbiologists investigate the growth , interactions and characteristics of microscopic organisms such as ___MASK22___ , algae , ___MASK51___ , and some types of parasites and their vectors . They contribute much to the field by trying to understand and learn about the interaction between these microbes and the environment and also among themselves and other organisms . Most microbiologists are qualified to work in offices and / or research facilities , such as a laboratory as well as in the academia . There , they conduct experiments that help them analyze microbes and their importance . A microbiologist ' s work is often repeated or improved in order to establish accurate research . Most microbiologists specialize in environmental , food , agricultural , industrial or medical aspects of microbiology including : virology ( the study of viruses ); immunology ( the study of mechanisms that fight infections ); bioinformatics ( the methods for storing , retrieving , organizing and analyzing biological data ) and Bioremediation ( using microbes as environmental mitigation strategies ). Many microbiologists use biotechnology to advance the understanding of cell reproduction and human disease . Some microbiologists have contributed to knowledge of pathogens and disease - causing microbes . While others , study their interaction with the environment and their use as potential environmental pollution cleaners . The " ___MASK23___ " are a major phylum of Gram - negative bacteria . The name of the phylum has never been validly published as no type genus has been proposed , thus it must be styled in quotation marks as the name has no standing in nomenclature . They include a wide variety of pathogens , such as " Escherichia ", " ___MASK93___ ", " ___MASK6___ ", " ___MASK73___ ", " ___MASK72___ ", and many other notable genera . Others are free - living ( nonparasitic ), and include many of the bacteria responsible for nitrogen fixation . Soil is a mixture of minerals , organic matter , gases , liquids , and countless organisms that together support life on Earth . Soil is a natural body called the pedosphere which has four important functions : it is a medium for ___MASK85___ growth ; it is a means of water storage , supply and purification ; it is a modifier of Earth ' s atmosphere ; it is a habitat for organisms ; all of which , in turn , modify the soil . The ___MASK75___ ( or or ) constitute a domain and kingdom of single - celled microorganisms . These microbes ( ___MASK75___ ; singular archaeon ) are ___MASK97___ , meaning that they have no cell nucleus or any other membrane - bound organelles in their cells . " ___MASK25___ " is a genus of rod - shaped chemoautotrophic ___MASK22___ . Binomial nomenclature ( also called binominal nomenclature or binary nomenclature ) is a formal system of naming species of living things by giving each a name composed of two parts , both of which use Latin grammatical forms , although they can be based on words from other languages . Such a name is called a binomial name ( which may be shortened to just " binomial "), a binomen or a scientific name ; more informally it is also called a Latin name . The first part of the name identifies the genus to which the species belongs ; the second part identifies the species within the genus . For example , humans belong to the genus " ___MASK42___ " and within this genus to the species " ___MASK42___ sapiens ". The " formal " introduction of this system of naming species is credited to Carl Linnaeus , effectively beginning with his work " Species Plantarum " in 1753 . But Gaspard Bauhin , in as early as 1623 , had introduced in his book " Pinax theatri botanici " ( English , " Illustrated exposition of plants ") many names of genera that were later adopted by Linnaeus . A genus ( genera ) is a taxonomic rank used in the biological classification of living and fossil organisms in biology . In the hierarchy of biological classification , genus comes above species and below family . In binomial nomenclature , the genus name forms the first part of the binomial species name for each species within the genus . In chemistry , esters are chemical compounds derived from an acid ( organic or inorganic ) in which at least one  OH ( hydroxyl ) group is replaced by an  O  alkyl ( alkoxy ) group . Usually , esters are derived from a carboxylic acid and an alcohol . Glycerides , which are fatty acid esters of glycerol , are important esters in biology , being one of the main classes of lipids , and making up the bulk of ___MASK88___ fats and vegetable oils . Esters with low molecular weight are commonly used as fragrances and found in essential oils and pheromones . Phosphoesters form the backbone of DNA molecules . Nitrate esters , such as nitroglycerin , are known for their explosive properties , while polyesters are important plastics , with monomers linked by ester moieties . Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate . The transformation of ammonia to nitrite is usually the rate limiting step of nitrification . Nitrification is an important step in the nitrogen cycle in soil . Nitrification is an aerobic process performed by small groups of autotrophic ___MASK22___ and archaea . This process was discovered by the Russian microbiologist Sergei Winogradsky . Hydrogen is a chemical element with chemical symbol H and atomic number 1 . With an atomic weight of , hydrogen is the lightest element on the periodic table . Its monatomic form ( H ) is the most abundant chemical substance in the Universe , constituting roughly 75 % of all baryonic mass . Non - remnant stars are mainly composed of hydrogen in the plasma state . The most common isotope of hydrogen , termed " ___MASK86___ " ( name rarely used , symbol H ), has one proton and no neutrons . Food is any substance consumed to provide nutritional support for the body . It is usually of ___MASK85___ or animal origin , and contains essential nutrients , such as carbohydrates , fats , proteins , vitamins , or minerals . The substance is ingested by an organism and assimilated by the organism ' s cells to provide energy , maintain life , or stimulate growth . A fertilizer ( American English ) or fertiliser ( British English ) is any material of natural or synthetic origin ( other than liming materials ) that is applied to soils or to ___MASK85___ tissues ( usually leaves ) to supply one or more ___MASK85___ nutrients essential to the growth of plants . ___MASK22___ ( common noun ___MASK22___ , singular bacterium ) constitute a large domain of prokaryotic microorganisms . Typically a few micrometres in length , ___MASK22___ have a number of shapes , ranging from spheres to rods and spirals . ___MASK22___ were among the first life forms to appear on Earth , and are present in most of its habitats . ___MASK22___ inhabit soil , water , acidic hot springs , radioactive waste , and the deep portions of Earth ' s crust . ___MASK22___ also live in symbiotic and parasitic relationships with plants and animals . Scarcity ( also called paucity ) is the fundamental economic problem of having seemingly unlimited ___MASK44___ wants in a world of limited resources . It states that society has insufficient productive resources to fulfill all ___MASK44___ wants and needs . Denitrification is a microbially facilitated process of nitrate reduction ( performed by a large group of heterotrophic facultative anaerobic ___MASK22___ ) that may ultimately produce molecular nitrogen ( N ) through a series of intermediate gaseous nitrogen oxide products . This respiratory process reduces oxidized forms of nitrogen in response to the oxidation of an ___MASK83___ donor such as organic matter . The preferred nitrogen ___MASK83___ acceptors in order of most to least thermodynamically favorable include nitrate ( NO ), nitrite ( NO ), nitric oxide ( NO ), nitrous oxide ( NO ) finally resulting in the production of dinitrogen ( N ) completing the nitrogen cycle . Denitrifying microbes require a very low oxygen concentration of less than 10 %, as well as organic C for energy . Since denitrification can remove NO , reducing its leaching to groundwater , it can be strategically used to treat sewage or animal residues of high nitrogen content . Denitrification allows for the production of NO , which is an ozone - depleting substance and a greenhouse gas that can have a considerable influence on global warming . Nitric oxide ( nitrogen oxide , nitrogen monoxide ) is a molecular , chemical compound with chemical formula of · NO . One of several oxides of nitrogen , it is a colorless gas under standard conditions . Nitric oxide is a free radical  i . e ., its bonding structure includes an unpaired ___MASK83___ , represented by the dot (·) on the nitrogen atom  and it is in the class of heteronuclear diatomic molecules that are of historic theoretical interest ( for the insights they gave in formulating early modern theories of bonding ). It is a particularly important intermediate in the chemical industry . In addition , some is unavoidably produced during combustion of fossil fuels in power plants and automobile engines , with excess being created when more air or higher temperatures are present than needed for efficient and complete combustion of the fuel . It is also produced naturally by the extremely high air temperatures produced along the path of lightning in thunderstorms . In biology , a phylum ( plural : ___MASK69___ ) is a taxonomic rank below kingdom and above class . Traditionally , in botany the term division was used instead of " phylum ", although from 1993 the International Code of Nomenclature for algae , ___MASK51___ , and plants accepted the designation " phylum ". Depending on definitions , the kingdom Animalia contains approximately 35 ___MASK69___ , Plantae contains about 12 , and ___MASK51___ contains around 7 . Current research in phylogenetics is uncovering the relationships between ___MASK69___ , which are contained in larger clades , like Ecdysozoa and Embryophyta . The nitrite ion , which has the chemical formula , is a symmetric anion with equal N  O bond lengths . Upon protonation , the unstable weak acid nitrous acid is produced . Nitrite can be oxidized or reduced , with the product somewhat dependent on the oxidizing / reducing agent and its strength . The nitrite ion is an ambidentate ligand , and is known to bond to metal centers in at least five different ways . Nitrite is also important in biochemistry as a source of the potent vasodilator nitric oxide . In organic chemistry the  NO group is present in nitrous acid esters and nitro compounds . Nitrites are also used in the food production industry for curing meat . ___MASK49___ is a genus of Gram - negative ___MASK22___ within family ___MASK67___ . There are two species in " ___MASK49___ " with standing in nomenclature , " ___MASK49___ winogradskyi " and " ___MASK49___ volutans ". The taxonomic position of three other species provisionally bearing the " ___MASK49___ " genus name (" ___MASK49___ minus ", " ___MASK49___ pleomorphum ", and " ___MASK49___ pulli ") is uncertain and these have no standing in nomenclature . The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into various chemical forms as it circulates among the atmosphere and terrestrial and marine ecosystems . The conversion of nitrogen can be carried out through both biological and physical processes . Important processes in the nitrogen cycle include fixation , ammonification , nitrification , and denitrification . The majority of Earth ' s atmosphere ( 78 %) is nitrogen , making it the largest pool of nitrogen . However , atmospheric nitrogen has limited availability for biological use , leading to a scarcity of usable nitrogen in many types of ecosystems . The nitrogen cycle is of particular interest to ecologists because nitrogen availability can affect the rate of key ecosystem processes , including primary production and decomposition . ___MASK44___ activities such as fossil fuel combustion , use of artificial nitrogen fertilizers , and release of nitrogen in wastewater have dramatically altered the global nitrogen cycle . Gas is one of the four fundamental states of matter ( the others being solid , liquid , and plasma ). A pure gas may be made up of individual atoms ( e . g . a noble gas like ___MASK4___ ), elemental molecules made from one type of atom ( e . g . oxygen ), or compound molecules made from a variety of atoms ( e . g . carbon dioxide ). A gas mixture would contain a variety of pure gases much like the air . What distinguishes a gas from liquids and solids is the vast separation of the individual gas particles . This separation usually makes a colorless gas invisible to the human observer . The interaction of gas particles in the presence of electric and gravitational fields are considered negligible as indicated by the constant velocity vectors in the image . One type of commonly known gas is steam . ___MASK73___ is a genus of Gram - negative ___MASK22___ possessing a characteristic helical shape . They were initially considered to be members of the " Campylobacter " genus , but in 1989 , Goodwin " et al ." published sufficient reasons to justify the new genus name " ___MASK73___ ". The " ___MASK73___ " genus contains about 35 species . ___MASK81___ - bite fever is an acute , febrile human illness caused by bacteria transmitted by rodents , rats , or mice , in most cases , which is passed from rodent to human by the rodent ' s urine or mucous secretions . Alternative names for ___MASK81___ - bite fever include streptobacillary fever , streptobacillosis , spirillary fever , " sodoku ", and epidemic arthritic erythema . It is a rare disease spread by infected rodents and can be caused by two specific types of bacteria . Most cases occur in Japan , but specific strains of the disease are present in the United States , Europe , Australia , and Africa . Some cases are diagnosed after patients were exposed to the urine or bodily secretions of an infected animal . These secretions can come from the mouth , nose , or eyes of the rodent . The majority of cases are due to the animal ' s bite . It can also be transmitted throughout food or water contaminated with ___MASK81___ feces or urine . Other animals can be infected with this disease , including weasels , gerbils , and squirrels . Household pets such as dogs or cats exposed to these animals can also carry the disease and infect humans . If a person is bitten by a rodent , it is important to quickly wash and cleanse the wound area thoroughly with antiseptic solution to reduce the risk of infection .