Rozellida
Encyclopedia
Cryptomycota or Rozellida are a clade
of micro-organisms which are either fungi or a sister group to fungi. They differ from classical fungi in that they lack chitinous cell walls.
The only formally described genus in the clade is Rozella
, which was previously considered a chytrid. The existence of related organisms was known from environmental DNA sequences.
Additional members of the group were isolated in 2011 by a team led by Thomas Richards, from the Natural History Museum in London, and also an evolutionary geneticist at the University of Exeter
, UK. The team used DNA
techniques to disclose the existence of unknown genetic material dredged from the university pond. Once they had a few unknown sequences they fluorescently
labeled small DNA sequence
s and let them bind to the matching DNA in the whole sample (Fluorescence in situ hybridization). Under fluorescence microscopy, they could see that the possessor cells were ovoid in shape and 3–5 micrometre
s across. They then established that the cryptomycota were present in other samples taken from further freshwater environments, soils and marine sediments.
The common characteristic of the clade members is that they lack the chitin
ous cell walls present in almost all previously discovered fungi (including microsporidia
) and which are a major feature of the kingdom. Without the chitin the cryptomycota can be phagotrophic parasites that feed by attaching to, engulfing, or living inside other cells. Most known fungi feed by osmotrophy
—taking in nutrients from outside the cell.
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of micro-organisms which are either fungi or a sister group to fungi. They differ from classical fungi in that they lack chitinous cell walls.
The only formally described genus in the clade is Rozella
Rozella
Rozella is a genus of fungi. Considered one of the earliest diverging lineages of fungi, the widespread genus contains 22 species. Rozella was circumscribed by French mycologist Marie Maxime Cornu in 1872.-Species:* Rozella achlyae...
, which was previously considered a chytrid. The existence of related organisms was known from environmental DNA sequences.
Additional members of the group were isolated in 2011 by a team led by Thomas Richards, from the Natural History Museum in London, and also an evolutionary geneticist at the University of Exeter
University of Exeter
The University of Exeter is a public university in South West England. It belongs to the 1994 Group, an association of 19 of the United Kingdom's smaller research-intensive universities....
, UK. The team used DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
techniques to disclose the existence of unknown genetic material dredged from the university pond. Once they had a few unknown sequences they fluorescently
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...
labeled small DNA sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
s and let them bind to the matching DNA in the whole sample (Fluorescence in situ hybridization). Under fluorescence microscopy, they could see that the possessor cells were ovoid in shape and 3–5 micrometre
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
s across. They then established that the cryptomycota were present in other samples taken from further freshwater environments, soils and marine sediments.
The common characteristic of the clade members is that they lack the chitin
Chitin
Chitin n is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world...
ous cell walls present in almost all previously discovered fungi (including microsporidia
Microsporidia
The microsporidia constitute a phylum of spore-forming unicellular parasites. They were once thought to be protists but are now known to be fungi. Loosely 1500 of the probably more than one million species are named now. Microsporidia are restricted to animal hosts, and all major groups of animals...
) and which are a major feature of the kingdom. Without the chitin the cryptomycota can be phagotrophic parasites that feed by attaching to, engulfing, or living inside other cells. Most known fungi feed by osmotrophy
Osmotrophy
Osmotrophy is the uptake of dissolved organic compounds by osmosis for nutrition. Organisms that use osmotrophy are osmotrophs. Some mixotrophic microorganisms use osmotrophy to derive energy.- References :#...
—taking in nutrients from outside the cell.