Biomaterial Database

The four genomes of the alga Pyrenomonas salina (Cryptophyta). 1992

U G Maier

Institute of Biology II, Freiburg, FRG.

Cryptomonads are a group of unicellular eukaryotic algae with unusual features. First, their plastids are surrounded by four membranes and second, between the two pairs of membranes there is a plasmatic compartment. This supernumerary eukaryotic compartment of the cryptomonad cell is devoid of mitochondria but contains starch grains, 80S ribosomes and a small vestigial eukaryotic nucleus called the nucleomorph. Isolation and characterization of the four genomes (from mitochondrion, plastid, nucleus and nucleomorph) of one cryptomonad, Pyrenomonas salina, demonstrates that the cryptomonads have originated from an unicellular organism related to green algae which endosymbiotically took up a eukaryotic protist related to the red algae.

UI	MeSH Term	Description	Entries
D002467	Cell Nucleus	Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	Cell Nuclei,Nuclei, Cell,Nucleus, Cell
D004272	DNA, Mitochondrial	Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.	Mitochondrial DNA,mtDNA
D005075	Biological Evolution	The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.	Evolution, Biological
D012335	RNA, Ribosomal	The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)	Ribosomal RNA,15S RNA,RNA, 15S
D013559	Symbiosis	The relationship between two different species of organisms that are interdependent; each gains benefits from the other or a relationship between different species where both of the organisms in question benefit from the presence of the other.	Endosymbiosis,Commensalism,Mutualism
D015388	Organelles	Specific particles of membrane-bound organized living substances present in eukaryotic cells, such as the MITOCHONDRIA; the GOLGI APPARATUS; ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.	Organelle
D016678	Genome	The genetic complement of an organism, including all of its GENES, as represented in its DNA, or in some cases, its RNA.	Genomes
D056890	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.	Eukaryotes,Eucarya,Eukarya,Eukaryotas,Eukaryote