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A complex photoreceptive structure in the cyanobacterium Leptolyngbya sp
P Albertano1, L Barsanti, V Passarelli
1Dipartimento di Biologia, Università di Roma Tor Vergata, Italy.
Micron (Oxford, England : 1993)
|November 24, 1999
Summary
Red cyanobacteria from Roman caves exhibit unique photobehavior. A specialized orange spot on their apical cells suggests a complex photoreceptive system, potentially involving a rhodopsin-like protein.
Area of Science:
- Microbiology
- Photosynthesis research
- Extremophile biology
Background:
- Terrestrial epilithic cyanobacteria inhabit diverse environments, including low-light conditions.
- Cyanobacteria are prokaryotes known for their photosynthetic capabilities.
- Some cyanobacteria exhibit phototaxis, a response to light stimuli.
Purpose of the Study:
- To investigate the photobehavior of a specific terrestrial epilithic cyanobacterium isolated from Roman hypogea.
- To characterize the photoreceptive mechanisms in this low-light adapted prokaryote.
- To explore the potential presence of novel photoreceptor systems in cyanobacteria.
Main Methods:
- Isolation and cultivation of cyanobacteria from Roman hypogea.
- Micro-spectrophotometric analysis of cellular structures.
- Photo-orientation experiments to assess light response.
- Analysis of impaired cells to identify molecular components.
Main Results:
- A non-heterocystous Leptolyngbya strain displayed significant photobehavior.
- Red cyanobacteria possessed an orange spot at the apical cell tip with absorption bands at 456 and 504 nm.
- Evidence suggests the presence of a rhodopsin-like protein in the apical tip structure.
Conclusions:
- The studied Leptolyngbya strain exhibits a complex photoreceptive system.
- The apical orange spot is likely involved in light perception and orientation.
- A rhodopsin-like protein may mediate this prokaryotic photoreception.