Planimal Cells: Artificial Photosynthetic Animal Cells Inspired by Endosymbiosis and Photosynthetic Animals

Abstract

I propose a new concept of artificial photosynthetic animal cells as planimal cells. Secondary endosymbiosis, symbiotic algae in animal cells and kleptoplasty evoke algae as the most fascinating autotrophic organisms for the creation of planimal cells. Strategies for the generation of planimal cells include three approaches, cell fusion between algae and animal cells, microinjection of algae into the cytoplasm of a host animal cell and creation of synthetic chimeric chromosomes with both algae and animal genomes. Planimal cells will contribute to overcoming global food problems by reducing energy consumption. Combining planimal cells with medical regeneration techniques will enable photosynthetic therapies. In the future, heterotrophs with planimal cells will support migration to other planets under the harsh conditions through long-distance space travel.

Effect of alkalinity and light intensity on the growth of the freshwater sponge Ephydatia fluviatilis (Porifera: Spongillidae)

“…Despite the joint importance of the different organisms in the sponge microbiome, possibly one of the most beneficial functional groups for the host is the photoautotrophs. Thanks to these symbioses, sponges can incorporate a remarkable part of the products of their host's photosynthetic metabolism (Matsunaga 2018), both by the input of photoassimilated carbon (Taylor et al 2007a, b), as well as nitrogen (Rix et al 2020). In addition, sponges benefit from oxygen production as a by-product of symbiont photosynthesis.…”

Nucleomorph: A Fascinating Remnant of Endosymbiosis

“…Algae originally emerged through evolutionary endosymbiosis; furthermore, some algae exist that emerged through a secondary endosymbiotic event. These organisms are interesting from both evolutionary and cell biological perspectives (Gentil et al 2017, Matsunaga et al 2018, Okabe and Matsunaga 2022. In this review, we discuss recent findings concerning organelles that provide direct evidence of secondary endosymbiosis, known as nucleomorphs.…”

“…It is important to note, however, that these experiments mimic primary endosymbiosis and not secondary endosymbiosis. The development of a system that precisely replicates secondary endosymbiosis between a eukaryotic host and a eukaryotic alga endosymbiont would therefore be extremely valuable for further research into the genome reduction of nucleomorphs (Matsunaga 2018).…”

A Photosynthetic Animal: A Sacoglossan Sea Slug that Steals Chloroplasts

“…A particular tool, which is currently the focus of re-search and development, is the use of long-coding DNA, involving synthesis on the genome-scale, construction of artificial organelles, and their insertion into artificial cells. A few laboratories are attempting to create artificial photosynthetic animal cells based on the concept of symbiosis (Matsunaga 2018, Puri et al 2021. We may be able to create photosynthetic animal cells that, like sea slugs, are capable of photosynthesis for several months using the following strategies: firstly, transfer of genes related to algal photosynthesis into the nucleus of cultured cells by HGT; secondly, use of microinjection technology to insert chloroplasts into cultured cells, imposed chloroplasts.…”