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Encyclopedia > Chlamydomonas reinhardtii
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How to read a taxobox
Chlamydomonas reinhardtii
Scientific classification
Kingdom: Protistae
Division: Chlorophyta
Class: Chlorophyceae
Order: Volvocales
Family: Chlamydomonadaceae
Genus: Chlamydomonas
Species: C. reinhardtii
Binomial name
Chlamydomonas reinhardtii
P.A.Dang.

Chlamydomonas reinhardtii is a motile single celled green alga about 10 micrometres in diameter that swims with two flagella. See Chlamydomonas. Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ... Typical phyla Chromista Heterokontophyta Haptophyta Cryptophyta (cryptomonads) Alveolata Dinoflagellata Apicomplexa Ciliophora (ciliates) Excavata Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Archaeplastida (in part) Rhodophyta (red algae) Glaucophyta (basal archaeplastids) Amoebozoa Choanozoa Many others; classification varies Protists (IPA: ) are a diverse group of organisms, comprising those eukaryotes that are not animals... Classes Chlorophyceae Ulvophyceae Trebouxiophyceae Prasinophyceae The Chlorophyta sensu stricto or chlorophytes, comprises most of what are commonly called green algae and includes most members of the grade of putatively ancestral scaly flagellates in Prasinophyceae plus members of Ulvophyceae, Trebouxiophyceae, Chlorophyceae, Pedinophyceae, Picocystophyceae, and unclassified Chlorophyta. ... Orders see text The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. ... Families Goniaceae Spondylomoraceae Tetrabaenaceae Volvocaceae The Volvocales are an order of flagellate or pseudociliate green algae which form planar or spherical colonies. ... Species See text. ... In biology, binomial nomenclature is the formal method of naming species. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... Divisions Chlorophyta Charophyta Streptophytina (Subdivision) The green algae are the large group of algae from which the embryophytes (higher plants) emerged. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the size of a droplet of mist or fog. ... A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ... Species See text. ...


These algae are commonly found in soil and fresh water. They have a cell wall made of hydroxyproline-rich glycoproteins, a large cup-shaped chloroplast and an "eyespot" that senses light. Normal Chlamydomonas can grow on a simple medium of inorganic salts in the light, using photosynthesis to provide energy. They can also grow in total darkness if acetate is provided as a carbon source. A cell wall is a fairly rigid layer surrounding a cell, located external to the cell membrane, that provides the cell with structural support, protection, and a filtering mechanism. ... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... The leaf is the primary site of photosynthesis in plants. ... Acetic acid, also known as ethanoic acid, is an organic chemical compound best recognized for giving vinegar its sour taste and pungent smell. ...


The C. reinhardtii wild type laboratory strain c137 (mt+) originates from an isolate made near Amherst, Massachusetts, in 1945.

Contents

C. reinhardtii as a model organism

Chlamydomonas is used as a model organism for research on fundamental questions in cell and molecular biology such as: A model organism is a species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ... Molecular biology is the study of biology at a molecular level. ...

  • How do cells move?
  • How do cells respond to light?
  • How do cells recognize one another?
  • How do cells regulate their proteome to control flagellar length?
  • How do cells repond to changes in mineral nutrition? (nitrogen, sulfur etc.)

There are many known mutants of C. reinhardtii. These mutants are useful tools for studying a variety of biological processes, including flagellar motility, photosynthesis or protein synthesis. A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ... The leaf is the primary site of photosynthesis in plants. ... Biological and artificial methods for creation of proteins differ significantly. ...


Reproduction

Vegetative cells of the reinhardtii species are haploid with 17 small chromosomes. Under nitrogen starvation, haploid gametes develop. There are two mating types, identical in appearance and known as mt(+) and mt(-), which can fuse to form a diploid zygote. The zygote is not flagellated, and it serves as a dormant form of the species in the soil. In the light the zygote undergoes meiosis and releases four flagellated haploid cells that resume the vegetative life cycle. Haploid (meaning simple in Greek) cells have only one copy of each chromosome. ... This article is about the biological chromosome. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Atomic mass 14. ... A gamete is a specialized germ cell that fuses with another gamete during fertilization (conception) in organisms that reproduce sexually. ... Mating type is the term applied to fungal hyphae that are found to have 2 or more distinct allele sites, distinguishing them as being either male, or female. It is necessary to have different mating types meet in order to have sexual reproduction. ... Diploid (meaning double in Greek) cells have two copies (homologs) of each chromosome (both sex- and non-sex determining chromosomes), usually one from the mother and one from the father. ... A zygote (Greek: ζυγωτόν) is a cell that is the result of fertilization. ... Not to be confused with miosis. ...


Curious fact: Under ideal growth conditions, cells may undergo two or three rounds of mitosis before the daughter cells are released from the old cell wall into the medium. Thus, a single growth step may result in 4 or 8 daughter cells per mother cell. Mitosis divides genetic information during cell division. ...


The cell cycle of this unicellular green algae can be synchronized by alternating periods of light and dark. The growth phase is dependent on light, whereas, after a point designated as the transition or commitment point, processes are light-independent. [1]


Evolution

Chlamydomonas has been used to study different aspects of evolutionary biology and ecology. The fact that: it has a short generation time, it is both a heterotroph and a facultative autotroph, it can reproduce both sexually and asexually and that there is already a lot of genetic information available for the species has made it an organism of choice for many selection experiments.


Some examples (non exhaustive) of evolutionary work done with Chlamydomonas go from the evolution of sexual reproduction, [2], the fitness effect of mutations [3], and the effect of adaptation to different levels of CO2. [4]


Genetics

The attractiveness of the alga as a model organism has recently increased with the release of several genomic resources to the public domain. The current draft (Chlre3) of the Chlamydomonas nuclear genome sequence prepared by Joint Genome Institute of the U.S. Dept of Energy comprises 1557 scaffolds totaling 120 Mb. Roughly half of the genome is contained in 24 scaffolds all at least 1.6 Mb in length. The sequences of all three C. reinhardtii genomes are available.


The ~15.8 Kb mitochondrial genome (database accession: NC_ 001638) is available online at the NCBI database. [1] The complete >200 Kb chloroplast genome is available online. [2] The current assembly of the nuclear genome is available online at. [3]


In addition to genomic sequence data there is a large supply of expression sequence data available as cDNA libraries and expressed sequence tags (ESTs). Seven cDNA libraries are available online [4]. A BAC library can be purchased from the Clemson University Genomics Institute [5]. There are also two databases of >50 000 [6] and >160 000 [7] ESTs available online.


C. reinhardtii DNA transformation techniques

Gene transformation occurs mainly by homologous recombination in the chloroplast and heterologous recombination in the nucleus. The C. reinhardtii chloroplast genome can be transformed using microprojectile particle bombardment and the nuclear genome has been transformed with both glass bead agitation and electroporation. The biolistic procedure appears to be the most efficient way of introducing DNA into the chloroplast genome. This is probably because the chloroplast occupies over half of the volume of the cell providing the microprojectile with a large target. Electroporation has been shown to be the most efficient way of introducing DNA into the nuclear genome with maximum transformation frequencies two orders of magnitude higher than obtained using glass bead method.


Notes

  1. ^ Oldenhof, H, Zachleder, V. and van den Ende, H. 2006. Blue- and red-light regulation of the cell cycle in Chlamydomonas reinhardtii (Chlorophyta). Eur. J. Phycol. 41: 313 - 320
  2. ^ Renaut et al. 2006 The ecology and genetics of fitness in Chlamydomonas. XIII. Fitness of long-term sexual and asexual populations in benign environments. Evolution 60: 2272-2279.
  3. ^ De Visser et al. 1996 The effect of sex and deleterious mutations on fitness in Chlamydomonas. Proc. R. Soc. Lond. B 263-193-200.
  4. ^ Collins & Bell. 2004. Phenotypic consequences of 1,000 generations of selection at elevated CO2 in a green alga Nature 431: 566-569.

External links

Major Model Organisms in Genetic Studies
Lambda phage | E. coli | Chlamydomonas | Tetrahymena | Budding yeast | Fission yeast | Neurospora | Maize | Arabidopsis | C. elegans | Drosophila | Zebrafish | Rat | Mouse

  Results from FactBites:
 
Chlamydomonas reinhardtii - Wikipedia, the free encyclopedia (632 words)
Chlamydomonas reinhardtii is a motile single celled green alga about 10 micrometres in diameter that swims with two flagella.
The origin of the C. reinhardtii WT laboratory strain c137 (mt+) is uncertain, but it is thought to have been collected from a field in New England in the 1940s.
Chlamydomonas is used as a model organism for research on fundamental questions in cell and molecular biology such as:
Chlamydomonas reinhardtii at the Crossroads of Genomics -- Grossman et al. 2 (6): 1137 -- Eukaryotic Cell (7325 words)
The chloroplast atpA gene cluster in Chlamydomonas reinhardtii.
Grossman, A. Chlamydomonas reinhardtii and photosynthesis: genetics to genomics.
Cotranscription of the wild-type chloroplast atpE gene encoding the CF1/CF0 epsilon subunit with the 3' half of the rps7 gene in Chlamydomonas reinhardtii and characterization of frameshift mutations in atpE.
  More results at FactBites »

 
 

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