Biomaterial Database

Production of nucleic acid-related substances by fermentation processes. 33. Accumulation of inosine by a mutant of Brevibacterium ammoniagenes. 1970

A Furuya, and S Abe, and S Kinoshita

Inosine-producing cultures were found among mutants resistant to 6-mercaptoguanine (6MG) derived from a 5'-inosinic acid (IMP)-producing strain, KY 13102, of Brevibacterium ammoniagenes. Inosine-producing ability was very frequent among the mutants resistant to a low concentration (10 to 50 mug/ml) of 6MG. The accumulation of inosine by strain KY 13714 was stimulated by a low concentration of adenine (25 mg/liter) but was depressed by high levels of adenine. The accumulation by strain KY 13714 was not inhibited by manganese ion but instead was stimulated by its excess, in contrast to IMP accumulation by KY 13102. Addition of hypoxanthine at an early stage of cultivation accelerated inosine accumulation. Furthermore, on addition of hypoxanthine and of a surface-activating agent after 48 hr of cultivation, the simultaneous accumulation of IMP and inosine was observed. A 9.3-mg amount of inosine per ml accumulated after 4 days of cultivation at 30 C. The inosine-producing mutant did not differ from the IMP-producing strain either in 5' purine nucleotide degradation or in IMP formation from hypoxanthine. However, it was found to be completely devoid of purine nucleoside-degrading activity. The conversion of IMP accumulation to inosine can be explained by the lack of nucleosidedegrading activity. The relationship between deficiency of nucleoside-degrading activity and resistance to low levels of 6MG is discussed, and a new mechanism for 6MG resistance is presented.

UI	MeSH Term	Description	Entries
D007042	Hypoxanthines	Purine bases related to hypoxanthine, an intermediate product of uric acid synthesis and a breakdown product of adenine catabolism.
D007477	Ions	An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.
D008345	Manganese	A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009705	Nucleosides	Purine or pyrimidine bases attached to a ribose or deoxyribose. (From King & Stansfield, A Dictionary of Genetics, 4th ed)	Nucleoside,Nucleoside Analog,Nucleoside Analogs,Analog, Nucleoside,Analogs, Nucleoside
D009711	Nucleotides	The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)	Nucleotide
D011687	Purines	A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.
D001951	Brevibacterium	A gram-positive organism found in dairy products, fresh and salt water, marine organisms, insects, and decaying organic matter.
D002474	Cell-Free System	A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)	Cellfree System,Cell Free System,Cell-Free Systems,Cellfree Systems,System, Cell-Free,System, Cellfree,Systems, Cell-Free,Systems, Cellfree
D002854	Chromatography, Paper	An analytical technique for resolution of a chemical mixture into its component compounds. Compounds are separated on an adsorbent paper (stationary phase) by their varied degree of solubility/mobility in the eluting solvent (mobile phase).	Paper Chromatography,Chromatographies, Paper,Paper Chromatographies