Aphanomyces: A genus of OOMYCETES in the family Saprolegniaceae. It causes root rot in plants and is also a pathogen of FISHES.Oomycetes: Eukaryotes in the group STRAMENOPILES, formerly considered FUNGI, whose exact taxonomic level is unsettled. Many consider Oomycetes (Oomycota) a phylum in the kingdom Stramenopila, or alternatively, as Pseudofungi in the phylum Heterokonta of the kingdom Chromista. They are morphologically similar to fungi but have no close phylogenetic relationship to them. Oomycetes are found in both fresh and salt water as well as in terrestrial environments. (Alexopoulos et al., Introductory Mycology, 4th ed, pp683-4). They produce flagellated, actively motile spores (zoospores) that are pathogenic to many crop plants and FISHES.Celosia: A plant genus of the family AMARANTHACEAE. Young leaves are used as vegetables in Asia. Members contain betacyanins, celogentins, betaxanthin, and celosian.Astacoidea: A superfamily of various freshwater CRUSTACEA, in the infraorder Astacidea, comprising the crayfish. Common genera include Astacus and Procambarus. Crayfish resemble lobsters, but are usually much smaller.Plant Root Cap: A cone-shaped structure in plants made up of a mass of meristematic cells that covers and protects the tip of a growing root. It is the putative site of gravity sensing in plant roots.DNA, Algal: Deoxyribonucleic acid that makes up the genetic material of algae.Methenamine: An anti-infective agent most commonly used in the treatment of urinary tract infections. Its anti-infective action derives from the slow release of formaldehyde by hydrolysis at acidic pH. (From Martindale, The Extra Pharmacopoeia, 30th ed, p173)Spores, Fungal: Reproductive bodies produced by fungi.Peas: A variable annual leguminous vine (Pisum sativum) that is cultivated for its rounded smooth or wrinkled edible protein-rich seeds, the seed of the pea, and the immature pods with their included seeds. (From Webster's New Collegiate Dictionary, 1973)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).Plant Diseases: Diseases of plants.Plant Roots: The usually underground portions of a plant that serve as support, store food, and through which water and mineral nutrients enter the plant. (From American Heritage Dictionary, 1982; Concise Dictionary of Biology, 1990)Fishes: A group of cold-blooded, aquatic vertebrates having gills, fins, a cartilaginous or bony endoskeleton, and elongated bodies covered with scales.