Flavobacterium: A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in SOIL and WATER. Its organisms are also found in raw meats, MILK and other FOOD, hospital environments, and human clinical specimens. Some species are pathogenic in humans.Flavobacteriaceae Infections: Infections with bacteria of the family FLAVOBACTERIACEAE.Fish Diseases: Diseases of freshwater, marine, hatchery or aquarium fish. This term includes diseases of both teleosts (true fish) and elasmobranchs (sharks, rays and skates).RNA, Ribosomal, 16S: Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.Cytophaga: A genus of gram-negative gliding bacteria found in SOIL; HUMUS; and FRESHWATER and marine habitats.Heparin Lyase: An enzyme of the isomerase class that catalyzes the eliminative cleavage of polysaccharides containing 1,4-linked D-glucuronate or L-iduronate residues and 1,4-alpha-linked 2-sulfoamino-2-deoxy-6-sulfo-D-glucose residues to give oligosaccharides with terminal 4-deoxy-alpha-D-gluc-4-enuronosyl groups at their non-reducing ends. (From Enzyme Nomenclature, 1992) EC 4.2.2.7.Oncorhynchus mykiss: A large stout-bodied, sometimes anadromous, TROUT found in still and flowing waters of the Pacific coast from southern California to Alaska. It has a greenish back, a whitish belly, and pink, red, or lavender stripes on the sides, with usually a sprinkling of black dots. It is highly regarded as a sport and food fish. Its former name was Salmo gairdneri. The sea-run rainbow trouts are often called steelheads. Redband trouts refer to interior populations of rainbows.Base Composition: The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.Antarctic Regions: The continent lying around the South Pole and the southern waters of the Atlantic, Pacific, and Indian Oceans. It includes the Falkland Islands Dependencies. (From Webster's New Geographical Dictionary, 1988, p55)DNA, Ribosomal: DNA sequences encoding RIBOSOMAL RNA and the segments of DNA separating the individual ribosomal RNA genes, referred to as RIBOSOMAL SPACER DNA.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Pentachlorophenol: An insecticide and herbicide that has also been used as a wood preservative. Pentachlorphenol is a widespread environmental pollutant. Both chronic and acute pentachlorophenol poisoning are medical concerns. The range of its biological actions is still being actively explored, but it is clearly a potent enzyme inhibitor and has been used as such as an experimental tool.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Polysaccharide-Lyases: A group of carbon-oxygen lyases. These enzymes catalyze the breakage of a carbon-oxygen bond in polysaccharides leading to an unsaturated product and the elimination of an alcohol. EC 4.2.2.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Osmeriformes: An order of fish including smelts, galaxiids, and salamanderfish.Fatty Acids: Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)Soil Microbiology: The presence of bacteria, viruses, and fungi in the soil. This term is not restricted to pathogenic organisms.Water Microbiology: The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Genes, rRNA: Genes, found in both prokaryotes and eukaryotes, which are transcribed to produce the RNA which is incorporated into RIBOSOMES. Prokaryotic rRNA genes are usually found in OPERONS dispersed throughout the GENOME, whereas eukaryotic rRNA genes are clustered, multicistronic transcriptional units.Ice Cover: A thick mass of ICE formed over large regions of land; RIVERS; LAKES; ponds; or SEAWATER.Fresh Water: Water containing no significant amounts of salts, such as water from RIVERS and LAKES.Bacterial Typing Techniques: Procedures for identifying types and strains of bacteria. The most frequently employed typing systems are BACTERIOPHAGE TYPING and SEROTYPING as well as bacteriocin typing and biotyping.Aquaculture: Cultivation of natural faunal resources of water. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Gram-Negative Bacterial Infections: Infections caused by bacteria that show up as pink (negative) when treated by the gram-staining method.