Raney nickel called spongy nickel, is a fine-grained solid composed of nickel derived from a nickel-aluminium alloy. Several grades are known; some are pyrophoric, most are used as air-stable slurries. Raney nickel is used as a catalyst in organic chemistry, it was developed in 1926 by American engineer Murray Raney for the hydrogenation of vegetable oils. Since Raney is a registered trademark of W. R. Grace and Company, only those products produced by its Grace Division are properly called "Raney nickel"; the more generic terms "skeletal catalyst" or "sponge-metal catalyst" may be used to refer to catalysts with physical and chemical properties similar to those of Raney nickel. However, since the Grace company itself does not use any generic names for the catalysts it supplies, "Raney" may become generic under US trademark law; the Ni–Al alloy is prepared by dissolving nickel in molten aluminium followed by cooling. Depending on the Ni:Al ratio, quenching produces a number of different phases.
During the quenching procedure, small amounts of a third metal, such as zinc or chromium, are added to enhance the activity of the resulting catalyst. This third metal is called a "promoter"; the promoter changes the mixture from a binary alloy to a ternary alloy, which can lead to different quenching and leaching properties during activation. In the activation process, the alloy as a fine powder, is treated with a concentrated solution of sodium hydroxide; the simplified leaching reaction is given by the following chemical equation: 2 Al + 2 NaOH + 6 H2O → 2 Na + 3 H2The formation of sodium aluminate requires that solutions of high concentration of sodium hydroxide be used to avoid the formation of aluminium hydroxide, which otherwise would precipitate as bayerite. Hence sodium hydroxide solutions with concentrations of up to 5 M are used; the temperature used to leach the alloy has a marked effect on the properties of the catalyst. Leaching is conducted between 70 and 100 °C; the surface area of Raney nickel tends to decrease with increasing leaching temperature.
This is due to structural rearrangements within the alloy that may be considered analogous to sintering, where alloy ligaments would start adhering to each other at higher temperatures, leading to the loss of the porous structure. During the activation process, Al is leached out of the NiAl3 and Ni2Al3 phases that are present in the alloy, while most of the Ni remains, in the form of NiAl; the removal of Al from some phases but not others is known as "selective leaching". The NiAl phase has been shown to provide the thermal stability of the catalyst; as a result, the catalyst is quite resistant to decomposition. This resistance allows Raney nickel to be reused for an extended period. For this reason, commercial Raney nickel is available in both "active" and "inactive" forms. Before storage, the catalyst can be washed with distilled water at ambient temperature to remove remaining sodium aluminate. Oxygen-free water is preferred for storage to prevent oxidation of the catalyst, which would accelerate its aging process and result in reduced catalytic activity.
Macroscopically, Raney nickel is a gray powder. Microscopically, each particle of this powder is a three-dimensional mesh, with pores of irregular size and shape of which the vast majority is created during the leaching process. Raney nickel is notable for being thermally and structurally stable, as well has having a large Brunauer-Emmett-Teller surface area; these properties are a direct result of the activation process and contribute to a high catalytic activity. The surface area is determined by a BET measurement using a gas, preferentially adsorbed on metallic surfaces, such as hydrogen. Using this type of measurement all the exposed area in a particle of the catalyst has been shown to have Ni on its surface. Since Ni is the active metal of the catalyst, a large Ni surface area implies a large surface is available for reactions to occur, reflected in an increased catalyst activity. Commercially available Raney nickel has an average Ni surface area of 100 m2 per gram of catalyst. A high catalytic activity, coupled with the fact that hydrogen is absorbed within the pores of the catalyst during activation, makes Raney nickel a useful catalyst for many hydrogenation reactions.
Its structural and thermal stability allows its use under a wide range of reaction conditions. Additionally, the solubility of Raney nickel is negligible in most common laboratory solvents, with the exception of mineral acids such as hydrochloric acid, its high density facilitates its separation from a liquid phase after a reaction is completed. Raney nickel is used in a large number of industrial processes and in organic synthesis because of its stability and high catalytic activity at room temperature. A practical example of the use of Raney nickel in industry is shown in the following reaction, where benzene is reduced to cyclohexane. Reduction of the benzene ring is hard to achieve through other chemical means, but can be effected by using Raney nickel. Other heterogeneous catalysts, such as those using platinum group elements, may be used instead, to similar effect, but these tend to be more expensive to produce than Raney nickel; the cyclohexane thus produced may be used in the synthesis of adipic acid, a raw material used in the industrial production of polyamides such as nylon.
Other industrial applications of Raney nickel include the
Hydrolysis is a term used for both an electro-chemical process and a biological one. The hydrolysis of water is the separation of water molecules into hydrogen and oxygen atoms using electricity. Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts; when a carbohydrate is broken into its component sugar molecules by hydrolysis, this is termed saccharification. Hydrolysis or saccharification is a step in the degradation of a substance. Hydrolysis can be the reverse of a condensation reaction in which two molecules join together into a larger one and eject a water molecule, thus hydrolysis adds water to break down, whereas condensation builds up by removing water and any other solvents. Some hydration reactions are hydrolysis. Hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both water molecule to split into two parts. In such reactions, one fragment of the target molecule gains a hydrogen ion.
It breaks a chemical bond in the compound. A common kind of hydrolysis occurs when a salt of weak base is dissolved in water. Water spontaneously ionizes into hydroxide anions and hydronium cations; the salt dissociates into its constituent anions and cations. For example, sodium acetate dissociates in water into acetate ions. Sodium ions react little with the hydroxide ions whereas the acetate ions combine with hydronium ions to produce acetic acid. In this case the net result is a relative excess of hydroxide ions. Strong acids undergo hydrolysis. For example, dissolving sulfuric acid in water is accompanied by hydrolysis to give hydronium and bisulfate, the sulfuric acid's conjugate base. For a more technical discussion of what occurs during such a hydrolysis, see Brønsted–Lowry acid–base theory. Acid–base-catalysed hydrolyses are common, their hydrolysis occurs when the nucleophile attacks the carbon of the carbonyl group of the ester or amide. In an aqueous base, hydroxyl ions are better nucleophiles than polar molecules such as water.
In acids, the carbonyl group becomes protonated, this leads to a much easier nucleophilic attack. The products for both hydrolyses are compounds with carboxylic acid groups; the oldest commercially practiced example of ester hydrolysis is saponification. It is the hydrolysis of a triglyceride with an aqueous base such as sodium hydroxide. During the process, glycerol is formed, the fatty acids react with the base, converting them to salts; these salts are called soaps used in households. In addition, in living systems, most biochemical reactions take place during the catalysis of enzymes; the catalytic action of enzymes allows the hydrolysis of proteins, fats and carbohydrates. As an example, one may consider proteases, they catalyse the hydrolysis of interior peptide bonds in peptide chains, as opposed to exopeptidases. However, proteases do not catalyse the hydrolysis of all kinds of proteins, their action is stereo-selective: Only proteins with a certain tertiary structure are targeted as some kind of orienting force is needed to place the amide group in the proper position for catalysis.
The necessary contacts between an enzyme and its substrates are created because the enzyme folds in such a way as to form a crevice into which the substrate fits. Therefore, proteins that do not fit into the crevice will not undergo hydrolysis; this specificity preserves the integrity of other proteins such as hormones, therefore the biological system continues to function normally. Upon hydrolysis, an amide converts into an amine or ammonia. One of the two oxygen groups on the carboxylic acid are derived from a water molecule and the amine gains the hydrogen ion; the hydrolysis of peptides gives amino acids. Many polyamide polymers such as nylon 6,6 hydrolyse in the presence of strong acids; the process leads to depolymerization. For this reason nylon products fail by fracturing. Polyesters are susceptible to similar polymer degradation reactions; the problem is known as environmental stress cracking. Hydrolysis is related to energy storage. All living cells require a continual supply of energy for two main purposes: the biosynthesis of micro and macromolecules, the active transport of ions and molecules across cell membranes.
The energy derived from the oxidation of nutrients is not used directly but, by means of a complex and long sequence of reactions, it is channelled into a special energy-storage molecule, adenosine triphosphate. The ATP molecule contains pyrophosphate linkages. ATP can undergo hydrolysis in two ways: the removal of terminal phosphate to form adenosine diphosphate and inorganic phosphate, or the removal of a terminal diphosphate to yield adenosine monophosphate and pyrophosphate; the latter undergoes further cleavage in
Simplified molecular-input line-entry system
The simplified molecular-input line-entry system is a specification in the form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules; the original SMILES specification was initiated in the 1980s. It has since been extended. In 2007, an open standard called. Other linear notations include the Wiswesser line notation, ROSDAL, SYBYL Line Notation; the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. Acknowledged for their parts in the early development were "Gilman Veith and Rose Russo and Albert Leo and Corwin Hansch for supporting the work, Arthur Weininger and Jeremy Scofield for assistance in programming the system." The Environmental Protection Agency funded the initial project to develop SMILES. It has since been modified and extended by others, most notably by Daylight Chemical Information Systems.
In 2007, an open standard called "OpenSMILES" was developed by the Blue Obelisk open-source chemistry community. Other'linear' notations include the Wiswesser Line Notation, ROSDAL and SLN. In July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is considered to have the advantage of being more human-readable than InChI; the term SMILES refers to a line notation for encoding molecular structures and specific instances should be called SMILES strings. However, the term SMILES is commonly used to refer to both a single SMILES string and a number of SMILES strings; the terms "canonical" and "isomeric" can lead to some confusion when applied to SMILES. The terms are not mutually exclusive. A number of valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol. Algorithms have been developed to generate the same SMILES string for a given molecule; this SMILES is unique for each structure, although dependent on the canonicalization algorithm used to generate it, is termed the canonical SMILES.
These algorithms first convert the SMILES to an internal representation of the molecular structure. Various algorithms for generating canonical SMILES have been developed and include those by Daylight Chemical Information Systems, OpenEye Scientific Software, MEDIT, Chemical Computing Group, MolSoft LLC, the Chemistry Development Kit. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database; the original paper that described the CANGEN algorithm claimed to generate unique SMILES strings for graphs representing molecules, but the algorithm fails for a number of simple cases and cannot be considered a correct method for representing a graph canonically. There is no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, double bond geometry; these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES.
A notable feature of these rules is. The term isomeric SMILES is applied to SMILES in which isotopes are specified. In terms of a graph-based computational procedure, SMILES is a string obtained by printing the symbol nodes encountered in a depth-first tree traversal of a chemical graph; the chemical graph is first trimmed to remove hydrogen atoms and cycles are broken to turn it into a spanning tree. Where cycles have been broken, numeric suffix labels are included to indicate the connected nodes. Parentheses are used to indicate points of branching on the tree; the resultant SMILES form depends on the choices: of the bonds chosen to break cycles, of the starting atom used for the depth-first traversal, of the order in which branches are listed when encountered. Atoms are represented by the standard abbreviation of the chemical elements, in square brackets, such as for gold. Brackets may be omitted in the common case of atoms which: are in the "organic subset" of B, C, N, O, P, S, F, Cl, Br, or I, have no formal charge, have the number of hydrogens attached implied by the SMILES valence model, are the normal isotopes, are not chiral centers.
All other elements must be enclosed in brackets, have charges and hydrogens shown explicitly. For instance, the SMILES for water may be written as either O or. Hydrogen may be written as a separate atom; when brackets are used, the symbol H is added if the atom in brackets is bonded to one or more hydrogen, followed by the number of hydrogen atoms if greater than 1 by the sign + for a positive charge or by - for a negative charge. For example, for ammonium. If there is more than one charge, it is written as digit.
A chiral auxiliary is a stereogenic group or unit, temporarily incorporated into an organic compound in order to control the stereochemical outcome of the synthesis. The chirality present in the auxiliary can bias the stereoselectivity of one or more subsequent reactions; the auxiliary can be recovered for future use. Most biological molecules and pharmaceutical targets exist as one of two possible enantiomers. Chiral auxiliaries are one of many strategies available to synthetic chemists to selectively produce the desired stereoisomer of a given compound. Chiral auxiliaries were introduced by E. J. Corey in 1975 with chiral 8-phenylmenthol and by B. M. Trost in 1980 with chiral mandelic acid; the menthol compound is difficult to prepare and as an alternative trans-2-phenyl-1-cyclohexanol was introduced by J. K. Whitesell in 1985. Chiral auxiliaries are incorporated into synthetic routes to control the absolute configuration of stereogenic centers. David Evans' synthesis of cytovaricin, considered a classic, utilizes oxazolidinone chiral auixiliaries for one asymmetric alkylation reaction and four asymmetric aldol reactions, setting the absolute stereochemistry of nine stereocenters.
A typical auxiliary-guided stereoselective transformation involves three steps: first, the auxiliary is covalently coupled to the substrate. The cost of employing stoichiometric auxiliary and the need to spend synthetic steps appending and removing the auxiliary make this approach appear inefficient. However, for many transformations, the only available stereoselective methodology relies on chiral auxiliaries. In addition, transformations with chiral auxiliaries tend to be versatile and well-studied, allowing the most time-efficient access to enantiomerically pure products. Furthermore, the products of auxiliary-directed reactions are diastereomers, which enables their facile separation by methods such as column chromatography or crystallization. In an early example of the use of a chiral auxiliary in asymmetric synthesis, E. J. Corey and coworkers conducted an asymmetric Diels-Alder reaction between -8-phenylmenthol acrylate ester and 5-benzyloxymethylcyclopentadiene; the cycloaddition product was carried forward to the iodolactone shown below, an intermediate in the classic Corey synthesis of the prostaglandins.
It is proposed that the back face of the acrylate is blocked by the auxiliary, so that cycloaddition occurs at the front face of the olefin. -8-phenylmenthol can be prepared from either enantiomer of pulegone, though neither route is efficient. Because of the widespread utility of the 8-phenylmenthol auxliliary, alternative compounds that are more synthesized, such as trans-2-phenyl-1-cyclohexanol and trans-2-cyclohexanol have been explored. 1,1’-Binaphthyl-2,2’-diol, or BINOL, has been used as chiral auxiliary for the asymmetric synthesis since 1983. Hisashi Yamamoto first utilized -BINOL as a chiral auxiliary in the asymmetric synthesis of limonene, an example of cyclic mono-terpenes. -BINOL monoeryl ether was prepared by the monosilylation and alkylation of -BINOL as the chiral auxiliary. Followed with the reduction by organoaluminum reagent, limonene was synthesized with low yields and moderate enantiomeric excesses up to 64% ee; the preparation of a variety of enantiomerically pure uncommon R-amino acids can be achieved by the alkylation of chiral glycine derivatives possessing axially chiral BINOL as an auxiliary.
It has been depicted by al.. Based on different electrophile, the diastereomeric excess varied from 69% to 86. Protected at the aldehyde function with -BINOL, arylglyoxals reacted diastereoselectively with Grignard reagents to afford protected atrolactaldehyde with moderate to excellent diastereomeric excess and high yields. One type of chiral auxiliary is based on the trans-2-phenylcyclohexanol motif as introduced by James K. Whitesell and coworkers in 1985; this chiral auxiliary was used in ene reactions of the derived ester of glyoxylic acid. In the total synthesis of -Heptemerone B and -Guanacastepene E, Attached with trans-2-pheynlcyclohexanol, the glyoxylate reacted with 2,4-dimethyl-2-pentene, in the presence of tin chloride, yielding the desired anti adduct as the major product, together with a small amount of its syn isomer with 10:1 diastereomeric ratio. For greater conformational control, switching from a phenyl to a trityl group gives trans-2-tritylcyclohexanol. In 2015, the Brown group published an efficient chiral permanganate-mediated oxidative cyclization with TTC.
Oxazolidinone auxiliaries, popularized by David Evans, have been applied to many stereoselective transformations, including aldol reactions, alkylation reactions, Diels-Alder reactions. The oxazolidinones are substituted at the 5 positions. Through steric hindrance, the substituents direct the direction of substitution of various groups; the auxiliary is subsequently removed e.g. through hydrolysis. Oxazolidinones can be prepared from amino acids or available amino alcohols. A large number of oxazolidinones are commercially available, including the four below. Acylation of the oxazolidinone is achieved by deprotonation with n-butyllithium and quench with an acid chloride. Deprotonation at the α-carbon of an oxazolidinone imide with a strong base such as lithium diisopropylamide selectively furnishes the -enolate, which can undergo stereoselective alkylation. Activated electrophiles, such as allylic or benz
Enzymes are macromolecular biological catalysts. Enzymes accelerate chemical reactions; the molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into different molecules known as products. All metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps; the study of enzymes is called enzymology and a new field of pseudoenzyme analysis has grown up, recognising that during evolution, some enzymes have lost the ability to carry out biological catalysis, reflected in their amino acid sequences and unusual'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins; the latter are called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction rate by lowering its activation energy; some enzymes can make their conversion of substrate to product occur many millions of times faster.
An extreme example is orotidine 5'-phosphate decarboxylase, which allows a reaction that would otherwise take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, nor do they alter the equilibrium of a reaction. Enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules: inhibitors are molecules that decrease enzyme activity, activators are molecules that increase activity. Many therapeutic drugs and poisons are enzyme inhibitors. An enzyme's activity decreases markedly outside its optimal temperature and pH, many enzymes are denatured when exposed to excessive heat, losing their structure and catalytic properties; some enzymes are used commercially, in the synthesis of antibiotics. Some household products use enzymes to speed up chemical reactions: enzymes in biological washing powders break down protein, starch or fat stains on clothes, enzymes in meat tenderizer break down proteins into smaller molecules, making the meat easier to chew.
By the late 17th and early 18th centuries, the digestion of meat by stomach secretions and the conversion of starch to sugars by plant extracts and saliva were known but the mechanisms by which these occurred had not been identified. French chemist Anselme Payen was the first to discover an enzyme, diastase, in 1833. A few decades when studying the fermentation of sugar to alcohol by yeast, Louis Pasteur concluded that this fermentation was caused by a vital force contained within the yeast cells called "ferments", which were thought to function only within living organisms, he wrote that "alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells."In 1877, German physiologist Wilhelm Kühne first used the term enzyme, which comes from Greek ἔνζυμον, "leavened" or "in yeast", to describe this process. The word enzyme was used to refer to nonliving substances such as pepsin, the word ferment was used to refer to chemical activity produced by living organisms.
Eduard Buchner submitted his first paper on the study of yeast extracts in 1897. In a series of experiments at the University of Berlin, he found that sugar was fermented by yeast extracts when there were no living yeast cells in the mixture, he named the enzyme that brought about the fermentation of sucrose "zymase". In 1907, he received the Nobel Prize in Chemistry for "his discovery of cell-free fermentation". Following Buchner's example, enzymes are named according to the reaction they carry out: the suffix -ase is combined with the name of the substrate or to the type of reaction; the biochemical identity of enzymes was still unknown in the early 1900s. Many scientists observed that enzymatic activity was associated with proteins, but others argued that proteins were carriers for the true enzymes and that proteins per se were incapable of catalysis. In 1926, James B. Sumner crystallized it; the conclusion that pure proteins can be enzymes was definitively demonstrated by John Howard Northrop and Wendell Meredith Stanley, who worked on the digestive enzymes pepsin and chymotrypsin.
These three scientists were awarded the 1946 Nobel Prize in Chemistry. The discovery that enzymes could be crystallized allowed their structures to be solved by x-ray crystallography; this was first done for lysozyme, an enzyme found in tears and egg whites that digests the coating of some bacteria. This high-resolution structure of lysozyme marked the beginning of the field of structural biology and the effort to understand how enzymes work at an atomic level of detail. An enzyme's name is derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase. Examples are alcohol dehydrogenase and DNA polymerase. Different enzymes that catalyze the same chemical reaction are called isozymes; the International Union of Biochemistry and Molecular Biology have developed a nomenclature for enzymes, the EC numbers. The first number broadly classifies the enzyme based on its mechanism; the top-level classification is: EC 1, Oxidoreductases: catalyze oxidation/reducti
Pseudomonas fluorescens is a common Gram-negative, rod-shaped bacterium. It belongs to the Pseudomonas genus. P. fluorescens has multiple flagella. It has an versatile metabolism, can be found in the soil and in water, it is an obligate aerobe, but certain strains are capable of using nitrate instead of oxygen as a final electron acceptor during cellular respiration. Optimal temperatures for growth of P. fluorescens are 25-30°C. It tests positive for the oxidase test, it is a nonsaccharolytic bacterial species. Heat-stable lipases and proteases are produced by other similar pseudomonads; these enzymes cause milk to spoil, by causing bitterness, casein breakdown, ropiness due to production of slime and coagulation of proteins. The word Pseudomonas means false unit, being derived from monas; the word was used early in the history of microbiology to refer to germs. The specific name fluorescens refers to the microbe's secretion of a soluble fluorescent pigment called pyoverdin, a type of siderophore.
The genomes of P. fluorescens strains Pf-5 and PfO-1 have been sequenced. There are two strains of Pseudomonas fluorescens associated with Dictyostelium discoideum. One strain serves as the other strain does not; the main genetic difference between these two strains is a mutation of the global activator gene called gacA. This gene plays a key role in gene regulation; some P. fluorescens strains present biocontrol properties, protecting the roots of some plant species against parasitic fungi such as Fusarium or the oomycete Pythium, as well as some phytophagous nematodes. It is not clear how the plant growth-promoting properties of P. fluorescens are achieved. The bacteria might outcompete other soil microbes, e.g. by siderophores, giving a competitive advantage at scavenging for iron. The bacteria might produce compounds antagonistic to other soil microbes, such as phenazine-type antibiotics or hydrogen cyanide. To be specific, certain P. fluorescens isolates produce the secondary metabolite 2,4-diacetylphloroglucinol, the compound found to be responsible for antiphytopathogenic and biocontrol properties in these strains.
The phl gene cluster encodes factors for 2,4-DAPG biosynthesis, regulation and degradation. Eight genes, phlHGFACBDE, are annotated in this cluster and conserved organizationally in 2,4-DAPG-producing strains of P. fluorescens. Of these genes, phlD encodes a type III polyketide synthase, representing the key biosynthetic factor for 2,4-DAPG production. PhlD shows similarity to plant chalcone synthases and has been theorized to originate from horizontal gene transfer. Phylogenetic and genomic analysis, has revealed that the entire phl gene cluster is ancestral to P. fluorescens, many strains have lost the capacity, it exists on different genomic regions among strains. Some experimental evidence supports all of these theories, in certain conditions. Several strains of P. fluorescens, such as Pf-5 and JL3985, have developed a natural resistance to ampicillin and streptomycin. These antibiotics are used in biological research as a selective pressure tool to promote plasmid expression; the strain referred to as Pf-CL145A has proved itself a promising solution for the control of invasive zebra mussels and quagga mussels.
This bacterial strain is an environmental isolate capable of killing >90% of these mussels by intoxication, as a result of natural product associated with their cell walls, with dead Pf-145A cells killing the mussels as well as live cells. Following ingestion of the bacterial cells mussel death occurs following lysis and necrosis of the digestive gland and sloughing of stomach epithelium. Research to date indicates high specificity to zebra and quagga mussels, with low risk of nontarget impact. Pf-CL145A has now been commercialized under the product name Zequanox, with dead bacterial cells as its active ingredient. Recent results showed the production of the phytohormone cytokinin by P. fluorescens strain G20-18 to be critical for its biocontrol activity by activating plant resistance. By culturing P. fluorescens, mupirocin can be produced, found to be useful in treating skin and eye disorders. Mupirocin free acid and its salts and esters are agents used in creams and sprays as a treatment of methicillin-resistant Staphylococcus aureus infection.
P. fluorescens demonstrates hemolytic activity, as a result, has been known to infect blood transfusions. P. fluorescens is an unusual cause of disease in humans, affects patients with compromised immune systems. From 2004 to 2006, an outbreak of P. fluorescens in the United States involved 80 patients in six states. The source of the infection was contaminated heparinized saline flushes being used with cancer patients. P. Fluorescens is a known cause of Fin rot in fish. P. fluorescens produces phenazine, phenazine carboxylic acid, 2,4-diacetylphloroglucinol and the MRSA-active antibiotic mupirocin. 4-Hydroxyacetophenone monooxygenase is an enzyme found in P. fluorescens that transforms piceol, NADPH, H+, O2 into 4-hydroxyphenyl acetate, NADP+, H2O. Appanna, Varun P..