Humanity has been actively trying to harness the power of the sun since the first magnifying glasses were developed for fire making in 7th century B.C. (US Department of Energy, n.d.). Since then, technological advancements have been made, allowing man to utilize solar energy to power buildings and even cars. Humanity is not alone in this effort to transform solar energy into a more useful form. It is commonly known that primary producers carry out the process of photosynthesis in order to convert light energy into chemical energy. However, it may be surprising to learn that other vertebrates, besides humans, are also capable of harnessing solar energy, albeit with a little help.
More than 120 years ago, scientists learned that the spotted salamander, Amybystoma maculatum, partakes in a mutualistic relationship with a species of algae, Oophila amblystomatis (Graham, et al. 2012). The algae were found to inhabit the eggs of the salamander embryos as they were forming (Refer to Figure; Petherick, 2010). It is speculated that the algae use the nitrogen-containing waste excreted by the embryos to aid in their growth, and in turn provide the embryos with extra oxygen. The mutualism of this relationship has been substantiated by studies demonstrating direct proportionality between algal and embryotic growth, and that embryos growing in the absence of their algal counterparts actually develop at a slower rate (Kerney, et al. 2011). However fascinating as this may seem, it was recently discovered that this animal-plant relationship is much more intimate than previously expected (Petherick, 2010). Scientists have found that these algae also live inside the embryo’s cells. Coexistence of this nature was only known to exist previously in invertebrates, such as coral. This discovery challenges the notion that a vertebrate’s adaptive immune system, which is responsible for recognizing and destroying foreign cells, should prevent such a relationship (Kerney, et al. 2011). It is especially interesting because scientists speculate that the algae could in fact be transmissible between mother and progeny, as algae have been discovered in the oviducts of adult female spotted salamanders.
Transmission electron microscopy has allowed scientists to capture images that illustrate a tendency for salamander mitochondria to congregate in close proximity to the intracellular algae (Kerney, et al. 2011). This suggests that the algae may also provide metabolic benefits to the host salamander cells. Scientists have found that fixed carbon is actively transferred from algae to the embryos. This provision of photosynthetically fixed carbon could be another reason for the accelerated embryotic growth and development of the embryotic cells. In addition to supplying extra oxygen and food to the embryos, studies have suggested that the algae provide protection to the embryos from harmful microbes via inhibition of bacterial growth. It is speculated that antibiotics may play a role, as some species of algae are known to release antibiotics (Graham, et al. 2012). This awesome relationship between plant and animal demonstrates how deep-seated connections can be in the natural world, and how little mankind knows about their intricacies.
Works Cited:
Graham, E., Fay, S., Davey, A., and Sanders, R. Intracapsular algae provide fixed carbon to developing embryos of the salamander Ambystoma maculatum. The Journal of Experimental Biology, [e-journal] 216, p. 452-459. Available at: <http://jeb.biologists.org/content/216/3/452.full.pdf+html> [Accessed 20 January 2013].
Kerney, R., Kim, E., Hangarter, R., Heiss, A., Bishop, C., and Hall, B., 2011. Intracellular invasion of green algae into a salamander host. Proceedings of the National Academy of Sciences, [e-journal] 108(16), p. 6497-6502. Available at: <http://www.pnas.org/content/108/16/6497.full> [Accessed 20 January 2013].
Petherick, A., 2010. Salamander’s egg surprise. [online] Available at: <http://www.nature.com/news/2010/100804/full/466675a.html> [Accessed 20 January 2013].
US Department of Energy, n.d. The History of Solar. [pdf] Available at: <http://www1.eere.energy.gov/solar/pdfs/solar_timeline.pdf> [Accessed 20 January 2013].