Chlorella: Nonmotile unicellular green algae potentially valuable as a source of high-grade protein and B-complex vitamins.Chlorella vulgaris: A species of green microalgae in the family Chlorellaceae. It is used as a model organism for PHOTOSYNTHESIS, and as a food supplement (DIETARY SUPPLEMENTS).Phycodnaviridae: A family of DNA plant viruses that infect eukaryotic algae.Microalgae: A non-taxonomic term for unicellular microscopic algae which are found in both freshwater and marine environments. Some authors consider DIATOMS; CYANOBACTERIA; HAPTOPHYTA; and DINOFLAGELLATES as part of microalgae, even though they are not algae.Eukaryota: One of the three domains of life (the others being BACTERIA and ARCHAEA), also called Eukarya. These are organisms whose cells are enclosed in membranes and possess a nucleus. They comprise almost all multicellular and many unicellular organisms, and are traditionally divided into groups (sometimes called kingdoms) including ANIMALS; PLANTS; FUNGI; and various algae and other taxa that were previously part of the old kingdom Protista.Nitrate Reductase (NADH): An NAD-dependent enzyme that catalyzes the oxidation of nitrite to nitrate. It is a FLAVOPROTEIN that contains IRON and MOLYBDENUM and is involved in the first step of nitrate assimilation in PLANTS; FUNGI; and BACTERIA. It was formerly classified as EC 126.96.36.199.Chlorophyta: A phylum of photosynthetic EUKARYOTA bearing double membrane-bound plastids containing chlorophyll a and b. They comprise the classical green algae, and represent over 7000 species that live in a variety of primarily aquatic habitats. Only about ten percent are marine species, most live in freshwater.Paramecium: A genus of ciliate protozoa that is often large enough to be seen by the naked eye. Paramecia are commonly used in genetic, cytological, and other research.Photobioreactors: Devices for generating biological products that use light as the energy source. They are used for controlled BIOMASS production such as growing cyanobacteria, mosses, or algae.Nitrate Reductases: Oxidoreductases that are specific for the reduction of NITRATES.Piper betle: A plant genus of the family PIPERACEAE that is indigenous in the Indian Malay region and cultivated in Madagascar, and the West Indies. It contains chavibetol, chavicol and cadinene. The leaf is chewed as a stimulant, antiseptic and sialogogue. The common name of betel is also used for ARECA.DNA, Algal: Deoxyribonucleic acid that makes up the genetic material of algae.Algal Proteins: Proteins found in any species of algae.