since moved to the National University of Singapore.">

Penguins with bad taste, and microbes with no taste!

By Steve Pointing 19/02/2015


Back in the TV3 studio for the live “Science Chat” feature on Firstline this morning.  Today I highlighted two breaking science stories that both used metagenomics to reveal strange eating habits:
http://www.3news.co.nz/nznews/penguins-cant-taste-fish-study-reveals-2015021912#axzz3S9gsr0cf

The first describes how some genes responsible for taste senses in penguins have been reduced to non-functional pseudogenes, leaving them with the ability to only taste salty and sour flavours.  In comparison other birds can also detect salty and umami flavours (but not sweet flavour as we humans can).  The study by US and Chinese researchers postulates this was due to evolution in the icy wilderness of Antarctica where taste perception is lower due to cold temperatures.  It is not hard to imagine how the bare minimum that evolution would leave a penguin with would be salty (seawater/freshwater perception?) and sour (perhaps to detect fermentation in rotten or diseased fish?).  Conversely birds in more temperate habitats could be envisaged to require bitter and umami taste perception to assess nuts, meat and other foods.  Of course the anatomy and behaviour of penguins could also be a factor – they swallow their food whole and have few taste receptors in their tongue, so perhaps it’s just a case of not needing taste buds!

Original article in Current Biology: http://www.sciencedirect.com/science/article/pii/S0960982215000573

Secondly I described the findings of a study to understand how microbial communities in coastal beaches respond to oil pollution.  The 2010 deepwater Horizon spill in the Gulf of Mexico left millions of gallons of oil buried in marine sediments off the Mississippi Delta, but significant amounts also washed up on beaches from Florida to Texas.  A metagenomic study of bacterial communities in sand revealed that prior to oil pollution photoautotrophy and nitrogen fixation were among the ‘positive’ ecosystem services bacteria performed.  These were lost when the oil hit, and the community was quickly dominated by proteobacteria that due to their highly plastic metabolism were able to utilise the oil as an energy and carbon source.  After one year oil was undetectable and so the rather unsavoury ‘eating’ of the oil was a welcome service (a good thing they don’t have any taste buds!). However it is not all good news, since the new ‘natural’ community, which was oil pollution sensitive, was nevertheless not the same as that which dominated before the oil spill – and so questions remain as to what long term effect on ecosystem function such an oil spill might have, even after the last traces of oil have apparently gone.

Original article in the ISME Journal:
http://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej20155a.html


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