Tag Archives: biology

The viruses that infect the bacteria that live in your gut

26 Monday Nov 2012

Posted by in Bacteria, Humans

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Electron micrograph of Bacteriophages (Photo credit: Wikipedia)Your body has ten times more bacterial cells than human cells containing 150 times as much genetic material.  I’ve written several posts about how our gut bacteria, the microbiome, can influence the development of allergies, obesity and type-2 diabetes.  We’ve only recently started studying the microbiome and there’s still a lot to learn; it’s quite an active area of research.  For example, just last year scientists discovered that individuals could be divided into three groups based on the composition of their microbiome, but new research has cast doubt on that idea.  And yet, like a matryoshka doll, our biology has still another surprise in store for us: wherever bacteria are found, there are viruses which infect them.  As we learn more about the microbiome and its implications, some scientists have turned their attention to the the viral microbiome, the viruses that prey on our gut bacteria and shape their community. Continue reading →

The basis of our overly optimistic beliefs

20 Tuesday Nov 2012

Posted by in Humans

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Optimism (Photo credit:verydemotivational.com)The human brain seems to be wired for forward-looking optimism.  In 2007, Tali Sharot and a team of scientists at University College London showed that people who were asked to imagine positive and negative future events consistently felt like the positive events are closer in time; the positive future events also felt closer than events in the past, whether positive or negative.  More recently, Dr. Sharot has turned her attention to the “good news/bad news effect”, our tendency to update our beliefs to reflect good news more than bad news.  Over the last few years, she and her team have identified the part of the brain responsible for this behaviour and even shown how to disrupt it.
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Do ants really count their steps?

09 Friday Nov 2012

Posted by in Arthropods, Humans, Hymenoptera, Mind

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Formica rufa Several years ago, scientists published an excellent study about how desert ants find their way home after foraging.  The story got a lot of media attention; unfortunately,  much of the coverage described the ants “counting steps”, which isn’t what the researchers reported and feeds into existing myths rather than broadening our scope.  To explain what I think is wrong with that approach, I’m going to tell you a story about ants on stilts, body swapping and how we perceive space. Continue reading →

Why do men and women want different things?

30 Tuesday Oct 2012

Posted by in Evolution, Humans

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Always close. (Photo credit: Hannele Luhtasela-El Showk)Regular readers will probably have realized from the links I share (or from my twitter stream) that sexism and gender issues are subjects which matter to me. Unfortunately, a lot of my discussions about gender get sidetracked by a “pop evolutionary” story based on naïve evolutionary psychology. We “evolved on the plains of Africa”, the story goes, where our preference in partners was shaped by biological needs; modern gender roles and partner preferences reflect these ancestral adaptations. It’s a nice story which does a great job of justifying the existing patriarchal structure, but is it true? That’s a huge question which is unlikely to be settled by a single study. Nevertheless, Marcel Zentner and Klaudia Mitura, a pair of psychologists at the University of York, decided to take it on. Continue reading →

Gut bacteria and diabetes: the saga continues

26 Friday Oct 2012

Posted by in Bacteria, Genetics, Humans

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Low-temperature electron micrograph of a cluster of E. coli bacteria, magnified 10,000 times. Each individual bacterium is oblong shaped. (Photo credit: Wikipedia)Type 2 diabetes is a serious global epidemic, having grown from 30 million cases to nearly 300 million over the past three decades. Although several recent studies have shown a link between type 2 diabetes and our gut bacteria, we’re still only at the dawn of learning about the microbiome. There’s a great deal we don’t yet know, including what kinds of bacteria live in our gut and how they go about making a living there. In a paper published in the September issue of Nature, a team of scientists from China and Denmark used whole genome sequencing technologies to overcome these gaps in our knowledge and get some more clues about the relationship between our gut bacteria and this disease. Continue reading →

Telling left from right: which side gets the heart?

23 Tuesday Oct 2012

Posted by in Development, Evolution, Form, Genetics, Vertebrates

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This was originally a guest post on The Trenches of Discovery. Thanks, Shaun!

Selection of internal organs in human anatomy. (Image credit: Wikipedia)One out of every 8,000 humans is born with some of their internal organs on the wrong side of their body, a condition which can have serious medical consequences. Although we’re usually described as symmetric, that’s only superficially true. Like other vertebrates, we look symmetric from the outside but our internal organs show left-right asymmetry; unless you happen to be a Time Lord, you have only one heart which is normally located on the left side of your chest.  Changes to the organization of the internal organs can lead to cardiac defects, misalignment of the bowel and other serious problems.  Many genes are known to play a role in establishing this asymmetry, but we still don’t fully understand its evolutionary and developmental origins.  Earlier this year, a paper published in the journal PNAS described how this asymmetry is established by  subcellular components early in embryonic development.

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