Chimaera Otherwise Blind Hatena to Detect the Felix Bast Light and to Swim Towards It
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FEATURE ARTICLE became a feeding apparatus of the animal kidnapper and developed a life- long allegiance to its captor, a sort of Bizarre World Stockholm Syndrome! Many single-celled algae like of Plant-Animal Nephroselmis have a region in their cell called eyespot, a heavily pigmented part that is attracted towards the light (a phenomenon called phototaxis). The eyespot of Nephroselmis enables the Chimaera otherwise blind Hatena to detect the Felix Bast light and to swim towards it. In other words, the algal eyespot works like an eye for Hatena. HE term ‘chimaera’ is used to Further research on its life cycle When the host animal cell divides refer to organisms with their revealed that these chloroplasts were into two, one daughter cell gets the Tbodies encompassing parts from indeed intact green algae Nephroselmis whole algae, and keeps on living like a other organisms. As a figment of human rotunda that the animal predated upon. photosynthetic animal, while the other imagination, one can find chimaeras in After eating these microscopic plants, daughter cell, now devoid of the alga, mythologies around the world. instead of digesting it, the animal kept lives like an animal until it ingests yet Many humans have also claimed it inside its sole cell. The algae supplied another alga. Scientists believe that this to possess plant-like photosynthetic the food that it photosynthesised to extraordinary situation in Hatena is due attributes. The concept of breatharianism its predator. The confined algae thus to ongoing “endosymbiosis.” or “Inedia” (Latin for fasting) is based on the belief that human beings have plant-like essence within, and can live A B without food forever; all we need is water and sunlight. However, most of these claims have been invalidated by modern scientific research; breatharianism is now considered to be a form of pseudoscience. There are, however, genuine cases of such plant-animal chimaeras one can find in nature. Most of these creatures often remain relatively unknown outside the arcane world of primary scientific research. So, let’s take a look at some C D interesting examples of chimaeras and other bizarre creatures that very well exist in nature. Endosymbionts Hatena arenicola is one such extraordinary animal discovered in the year 2000 by two Japanese scientists. The scientists observed single-celled animals (flagellate eukaryotes) living on a beach in Japan with chloroplasts— the photosynthesising organelle. Endosymbionts: A) Hatena arenicola (Image credit: Scientific American). N indicates the nucleus Animal cells usually do not contain of the host heterotroph, while S indicates the symbiont alga Nephroselmis rotunda. The arrow chloroplasts — one of the principal indicates the location of the eyespot. B) Paulinella chromatophora (Image credit: www.arcella.nl). distinguishing characteristics between C) Algae Oophila amblystomatis inside spotted salamander embryos (Image credit: Wikimedia). animals and plants. D) Sea slug Elysia chlorotica (Image credit: Patrick Krug/MBL). 26 | Science Reporter | January 2019 Endosymbiosis (endo = inside, Instead of killing and ingesting it, the even been strategized by vertebrates. symbiosis = living together) is a amoeba commanded the plant hostage Consider an extraordinary amphibian, prominent theory in cell biology to make food for it, what a clever tactic! spotted salamander (Ambystoma first formulated by Russian botanist Imagine we also command the maculatum). The salamander acquires Konstantin Mereschkowski in 1905 plants we eat; that would result in a Oophila amblystomatis, a green alga, explaining the origin of organelles photosynthetic human being. A human right during its embryo phase. Nitrogen- –intracellular membrane–bound that needs no food; she can make the rich embryonic fluid fosters algal structures of eukaryotes (cells with true food within herself. All she needs is growth; while algae provide oxygen nucleus and organelles). The theory sunlight and water just like plants, the and sugar to the developing embryo, posits that eukaryotes originated when fantasy world of breatharians. Solar- the embryo provides carbon dioxide for a prokaryote (bacteria) ingested yet powered human beings! The 2006 the algal photosynthesis. As the embryo another bacteria. The ingested bacteria, science fiction “Stuffing” by Jerry develops, the algae suffuse throughout instead of getting digested, stayed there Oltion depicts such a photosynthetic the salamander’s body. However, and evolved into an organelle that human being (“Wings” series by unlike the embryo phase, the matured divides when its host cell divides. Aprilynne Pike is yet another example). salamanders are not photosynthetic. Each cell of our body has With the advent of genetic an organelle (mitochondrion, the engineering and genome editing Symbionts powerhouse of the cell), formed this tools like CRISPR-CAS9, scientists A relationship with algae has been way; the relic of a bacterial food that have already begun discussing the reported for yet another amphibian, the our bacterial ancestor billions of years possibility of creating such a plant- American toad (Anaxyrus americanus). ago ingested. Current estimates suggest animal hybrid, with animal cells having Tadpoles of this toad secrete inorganic that the eukaryotes originated this way either the crucial solar energy capturing approximately 2.7 billion years ago. mechanisms or the complete organelles nutrients that render green algae of the Imagine swallowing a live fish, and the of chloroplasts for photosynthesis. genus Chlorogonium attracted to it. The algae grow on the tadpoles as an fish lives happily inside our stomach, The story of the green sea slug appendage, providing oxygen and food and evolves to be one of our organs! (Elysia chlorotica) is even bizarre. to the developing frog. The tadpole Queer as it would seem, that is how the These marine gastropod animals provides nutrients and carbon dioxide mitochondria originated. (mollusk) ingest intertidal green algae, for the growth of the algae. Plants have another such organelle, Vaucheria litorea. Instead of killing and the photosynthesising chloroplasts, in ingesting the whole algae, the animal’s The mutualism between tadpoles addition to mitochondria. Chloroplasts gut absorbs the algal chloroplasts intact and algae is an example of symbiosis – were once photosynthetic bacteria through a process called phagocytosis long-term interaction of two organisms (blue-green algae), the food that an (“cell eating”). The intact chloroplasts – and is different from endosymbiosis. animal cell ingested approximately 2 thus absorbed become integrated into The key difference is that in the case billion years ago. the animal cells, where they grow as of endosymbiosis, one organism In a way, plants are more a stolen chloroplast (“kleptoplast”). becomes an organelle within the cells ‘accomplished’ living beings; they The algal prisoner now captures of another organism, while in the case have chloroplasts and mitochondria, solar energy, diligently performs of symbiosis both the organisms are while animals have only mitochondria. photosynthesis, and provides food for separate living entities. Animal-plant Look at the world of plants around the slug. symbiosis is indeed a well-documented you; are these merely plants? Plants are The case of the marine ciliate phenomenon. indeed living examples of the animal- unicellular animal, Myrionecta rubra, is Two well-known examples are plant chimaera; a primitive animal that very similar. These ciliates appropriate corals and lichens. In the case of corals, acquired photosynthetic ability from the intact chloroplasts from the algal cnidarian animals have a symbiotic a blue-green alga (the closest living food (a species of cryptomonad algae), relationship with dinoflagellate algae, relative of this first algal food is marine and these become kleptoplasts lending Symbiodinium. In the case of lichens, picoplankton Synechococcus) that they a photosynthetic capability to the host. fungi and yeast have a symbiotic ingested. Mesodinium chamaeleon, yet another relationship with green algae or Paulinella chromatophora, an marine ciliate, eats plants (green and cyanobacteria. The algal partners in amoeboid animal, recently (100 million red algae), and the algal chloroplasts both of these associations fix the carbon years ago, which is comparatively very get integrated into the eukaryotic cell dioxide through photosynthesis and recent in the history of life on this carrying out photosynthesis. provide food to their partner. These planet) did the exact same thing that the The strategy of acquisition of associations were previously thought animal ancestor of plants did 2 billion photosynthetic potential by selective to be mutualistic, benefitting both years ago — it ate a cyanobacterium. phagocytosis of the algal chloroplast has the partners. January 2019 | Science Reporter | 27 A B C D A. Leaf insect (Image credit: Wikimedia). B. Bee orchid (Image credit: Wikimedia). C. Wasp Lissopimpla excelsa pseudomating on orchid Cryptostylis (Image credit: Mitch Smith). D. Stick insect (Image credit: Wikimedia). While algae can very well live Solar-powered Animals the hornet’s locomotion. Stored outside the partnership, its partners We have seen so far that algae are the electricity is also released as light (cnidarian animal in the case of corals only plant group involved in all these during darkness. or fungi in the case of lichens) cannot. animal-plant hybrids. However, there Similar solar energy