Phycomyces blakesleeanus
Encyclopedia
Phycomyces blakesleeanus (Algal fungi) is a filamentous fungus
in the Order Mucorales
of the phylum Zygomycota
or subphylum Mucormycotina. The spore-bearing sporangiophores of Phycomyces are very sensitive to different environmental signals including light, gravity, wind, chemicals and adjacent objects. They exhibit phototropic growth, and most Phycomyces research has focused on sporangiophore photobiology
, such as phototropism
and photomecism ('light growth response'). Metabolic, developmental, and photoresponse mutants have been isolated, some of which have been genetically mapped. At least ten different genes (named madA through to madJ) are required for phototropism. The madA gene encodes a protein related to the White Collar 1 class of photoreceptors that are present in other fungi, while madB encodes a protein related to the White Collar 2 protein that physically bind to White collar 1 to participate in the responses to light .
Phycomyces also exhibits an avoidance response, in which the growing sporangiophore avoids solid objects in its path, bending away from them and then continuing to grow upward again. This is believed to result from an unidentified "avoidance gas" that is emitted by the growing zone of the sporangiophore. This gas would concentrate in the airspace between the Phycomyces and the object. This higher concentration would be detected by the side of the sporangiophore's growing zone, which would grow faster, causing the sporangiophore to bend away.
Phycomyces blakesleeanus became the primary organism of research by the Nobel laureate Max Delbrück
starting in the 1950s, when Delbrück decide to switch from research on bacteriophage and bacteria to P. blakesleeanus.
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
in the Order Mucorales
Mucorales
The Mucorales is the largest and best studied order of Zygomycete fungi. Members of this order are sometimes called pin molds.-Systematics:...
of the phylum Zygomycota
Zygomycota
Zygomycota, or zygote fungi, is a phylum of fungi. The name comes from zygosporangia, where resistant spherical spores are formed during sexual reproduction. Approximately 1060 species are known. They are mostly terrestrial in habitat, living in soil or on decaying plant or animal material...
or subphylum Mucormycotina. The spore-bearing sporangiophores of Phycomyces are very sensitive to different environmental signals including light, gravity, wind, chemicals and adjacent objects. They exhibit phototropic growth, and most Phycomyces research has focused on sporangiophore photobiology
Photobiology
Photobiology is the scientific study of the interactions of light and living organisms. The field includes the study of photosynthesis, photomorphogenesis, visual processing, circadian rhythms, bioluminescence, and ultraviolet radiation effects...
, such as phototropism
Phototropism
Phototropism is directional growth in which the direction of growth is determined by the direction of the light source. In other words, it is the growth and response to a light stimulus. Phototropism is most often observed in plants, but can also occur in other organisms such as fungi...
and photomecism ('light growth response'). Metabolic, developmental, and photoresponse mutants have been isolated, some of which have been genetically mapped. At least ten different genes (named madA through to madJ) are required for phototropism. The madA gene encodes a protein related to the White Collar 1 class of photoreceptors that are present in other fungi, while madB encodes a protein related to the White Collar 2 protein that physically bind to White collar 1 to participate in the responses to light .
Phycomyces also exhibits an avoidance response, in which the growing sporangiophore avoids solid objects in its path, bending away from them and then continuing to grow upward again. This is believed to result from an unidentified "avoidance gas" that is emitted by the growing zone of the sporangiophore. This gas would concentrate in the airspace between the Phycomyces and the object. This higher concentration would be detected by the side of the sporangiophore's growing zone, which would grow faster, causing the sporangiophore to bend away.
Phycomyces blakesleeanus became the primary organism of research by the Nobel laureate Max Delbrück
Max Delbrück
Max Ludwig Henning Delbrück was a German-American biophysicist and Nobel laureate.-Biography:Delbrück was born in Berlin, German Empire...
starting in the 1950s, when Delbrück decide to switch from research on bacteriophage and bacteria to P. blakesleeanus.