Photobacterium: A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that are common in the marine environment and on the surfaces and in the intestinal contents of marine animals. Some species are bioluminescent and are found as symbionts in specialized luminous organs of fish.Vibrionaceae: A family of gram-negative bacteria whose members predominate in the bacterial flora of PLANKTON; FISHES; and SEAWATER. Some members are important pathogens for humans and animals.Luminescence: Emission of LIGHT when ELECTRONS return to the electronic ground state from an excited state and lose the energy as PHOTONS. It is sometimes called cool light in contrast to INCANDESCENCE. LUMINESCENT MEASUREMENTS take advantage of this type of light emitted from LUMINESCENT AGENTS.Vibrio: A genus of VIBRIONACEAE, made up of short, slightly curved, motile, gram-negative rods. Various species produce cholera and other gastrointestinal disorders as well as abortion in sheep and cattle.Hydrostatic Pressure: The pressure due to the weight of fluid.Hyphomicrobium: A genus of rod-shaped, oval, or bean-shaped bacteria found in soil and fresh water. Polar prosthecae are present and cells reproduce by budding at the tips of the prosthecae. Cells of this genus are aerobic and grow best with one-carbon compounds. (From Bergey's Manual of Determinative Bacteriology, 9th ed)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).Bass: Common name for FISHES belonging to the order Perciformes and occurring in three different families.Luminescent Measurements: Techniques used for determining the values of photometric parameters of light resulting from LUMINESCENCE.Seawater: The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.Fishes: A group of cold-blooded, aquatic vertebrates having gills, fins, a cartilaginous or bony endoskeleton, and elongated bodies covered with scales.Gram-Negative Bacterial Infections: Infections caused by bacteria that show up as pink (negative) when treated by the gram-staining method.RNA, Ribosomal, 16S: Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.Sialyltransferases: A group of enzymes with the general formula CMP-N-acetylneuraminate:acceptor N-acetylneuraminyl transferase. They catalyze the transfer of N-acetylneuraminic acid from CMP-N-acetylneuraminic acid to an acceptor, which is usually the terminal sugar residue of an oligosaccharide, a glycoprotein, or a glycolipid. EC 2.4.99.-.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Benzethonium: Bactericidal cationic quaternary ammonium surfactant used as a topical anti-infective agent. It is an ingredient in medicaments, deodorants, mouthwashes, etc., and is used to disinfect apparatus, etc., in the food processing and pharmaceutical industries, in surgery, and also as a preservative. The compound is toxic orally as a result of neuromuscular blockade.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.Animal Structures: Organs and other anatomical structures of non-human vertebrate and invertebrate animals.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.