#ocelloid

[todropscience]

ONE-CELLED PLANKTONIC ORGANISM HAVE ANIMAL-LIKE EYES

Multicellularity is often considered a prerequisite for morphological complexity, as seen in the camera-type eyes found in several groups of animals. A notable exception exists in single-celled eukaryotes called dinoflagellates, some of which have an eye-like ‘ocelloid’ consisting of subcellular analogues to a cornea, lens, iris, and retina

According to a canadian research team at the University of British Columbia, the single celled organism called  warnowiid dinoflagellate evolved a tiny version of a multi-cellular eye. In fact, contains a collection of sub-cellular organelles that look very much like the lens, cornea, iris and retina of multicellular eyes found in large animals.  The ocelloid, who is named the structure, could be used to detect shifts in light as it passed through their transparent prey

This process is known as convergent evolution, when different animals can evolve similar traits in response to their environments.

Warnowiids are found in marine plankton, little is known about their life histories, because they cannot be cultured in the laboratory, and samples obtained from the natural environment do not survive well under laboratory conditions

Light micrograph of a single Warnowia isolate. Scale bar = 10 microns, from Hoppenrath et al. 2009. 

Reference: Gavelis et al. 2015. Eye-like ocelloids are built from different endosymbiotically acquired components Nature

Illustration credit: Gregory S. Gavelis et al. 2015

[wran]

Single-Celled Creature Has Eye Made of Domesticated Microbes

Under the microscope, each warnowiid contains a conspicuous dark dot. This is the ocelloid. It consists of a clear sphere sitting in front of a dark red strip, and has components that resemble a lens, an iris, a cornea, and a retina.

Eyes are meant to be animal inventions. They’re supposed to comprise many cells. They are icons of biological complexity. And yet, here’s a non-animal that packs similar components into its single cell. Is the ocelloid actually an eye? Can it sense light? What does a warnowiid use it for? These questions are still mysteries, but in trying to answer them, Gregory Gavelis from the University of British Columbia has discovered something about the ocelloid that’s even weirder. At least two of its components—the “retina” and the “cornea”—seem to be made from domesticated bacteria.

[mucholderthen]

A Fork in the Red Micrographs of red algae on glass By The Ocelloid @ Scientific American

Isn't it great when your art subjects cooperate and model themselves? Algae are inherently photogenic — especially [since] they look like fuzz or goo to the naked eye! While many macro algae (those big seaweeds you find on the beach) require considerable skill and equipment to show off at their best, filamentous algae are usually thin enough to fend for themselves.

And while we’re well-acquainted with seeing green in photosynthetic critters, red algae [rhodophyta] really take a turn for the alien. And vibrantly so — the camera hardly does justice to what you can actually see in the scope!

For info on the images, go to Ocelloid's Scientific American blog ...