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March 2015 Archives

One of the books I'm currently reading is the excellent The Man Who Touched His Own Heart, by Rob Dunn. It's a fascinating and beautifully-written narrative of how our understanding of both the heart and of ways to treat its disorders have developed over the centuries (& yes, I will review the book properly when I've finished it). 

In one chapter Dunn mixes archaeology, history, medicine & science in the tale of Egyptian queen Meryet-Amun's life and death. (I loved this chapter for the way it reminded me of some of the late Elizabeth Peters' 'Amelia Peabody' novels.) It's a tale that stretches a long way back through time, but the denouement came in 2008, when cardiologists visiting the Egyptian National Museum of Antiquities came across a mummy (not the queen's, but that of a son of Ramesses II) with a label saying that the man had suffered from atherosclerosis.

To the cardiologists this had to be wrong, as everyone 'knew' that the buildup of fatty 'plaque' in our blood vessels was a modern disease. As Dunn writes, 

[as] nations become developed, they are saved from the contagions and diseases of infancy and youth, and cardiovascular disease kills in their place

and cardiovascular disease is generally preceded by the deposition of plaques in our arteries. However, it turned out that 

no one knew for sure when atherosclerosis had begun.

The collection of bodies in the Museum offered the potential for finding out. It took a considerable amount of effort to get permission to handle the remains of these ancient kings and queens and their retainers, but eventually the research team was ready to put 45 mummies (the best preserved of the 120 on offer) through a whole-body CT scanner. All bodies were of adults, and came from dates ranging between 1981 BC and AD 364; all had been members of their societies' elite, or their attendants.

Forty-three bodies contained at least some vascular tissue, and 31 contained bits of the heart (usually returned to the body during mummification) - and 45% of those bodies contained atherosclerotic plaques in their blood vessels.

And Queen Meryet-Amun? All her arteries - including the coronary arteries - contained plaque. 

[Her] heart was, in a way, far heavier than the feather [against which ancient Egyptians believed it was weighed by the gods]. It was weighed down with our 'modern plague'.

Now, these were all rather affluent folks, but surely hard-working farmers & hunter-gatherers would be free of any sign of cardiovascular disease? The team looked at mummies from Rome, ancient Peru, the ancient US Pueblo farmers, and Aleutian Island hunter-gatherers - and found atherosclerosis in people from all ages and all the cultures examined. Dunn quotes the researchers as saying that 

The presence of atherosclerosis in pre-modern human beings suggests that the disease is an inherent component of human ageing and not associated with any specific diet or lifestyle.

Then what about cancer, another 'modern' disease (or more properly, collection of diseases)? If you spend time in various on-line fora you'll find cancer linked (by not-always-reputable sources) to lifestyle, pesticides, fluoride, & the ubiquitous but seldom-identified 'toxins'. (And, of course, to age, for many people now live long enough to die of cancers rather than with them.) Back in 2010 an article based on research from the University of Manchester stated that cancer was so rare in Egyptian mummies that it had to be a modern disease1. In fact, in that article one scientist was quoted as saying that

[there] is nothing in the natural environment that can cause cancer.

Now, while it's undoubtedly true that there are many things we do (smoking, anyone?) that can increase the risk of cancer, it is also true that completely natural factors are also implicated: radon, UV radiation, and arsenic, for example.  

And there is additional, more recent, evidence that cancer afflicted ancient peoples as well. The body of an Egyptian woman who died 4,200 years ago shows signs of metastases from breast cancer; and a 3,000-year-old skeleton from the Sudan also showed widespread metastases in its bones. In fact, what is probably the oldest written description of cancer comes from a 3,000-year-old papyrus (which says of the disease that "there is no treatment"). And Hippocrates was almost certainly writing about cancer, more than 2,000 years ago, when he

used the terms carcinos and carcinoma to describe non-ulcer-forming and ulcer-forming tumours

which suggests he had encountered at least several examples during his career.

This 'emperor of all maladies' may not have been as common back then as it is today, but both it and cardiovascular disease are not exactly 'modern'.

EDIT: interested readers will enjoy Orac's coverage of this issue, over at Respectful Insolence.

1 The statement from the same source that "the first reports in scientific literature of distinctive tumours have only occurred in the past 200 years, such as scrotal cancer in chimney sweeps in 1775, nasal cancer in snuff users in 1761, and Hodgkin's disease in 1832" may possibly reflect the fact that what we'd recognise as 'scientific literature' probably hasn't been around much longer, given that the oldest scientific English-language journal, the Philosophical Transactions of the Royal Society, was established 'only' in 1665.

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I've always liked frogs. I remember, when I was probably around 4 years old, being fascinated by the tadpoles that Dad brought home in a big jar from a farm pond. Mum explained about how they'd gradually metamorphose (thought I doubt she used that word!) & we watched their legs slowly grow & their tails disappear as they swam around in an old tub, until the point where they became frogs.

Frogs are amphibians, along with newts & mud-puppies & axolotls and the legless caecilians (which look like a cross between an eel and an earthworm). As a group, frogs are much younger - in geological terms - than the others: most fossil frogs date back only about 50 million years, although the earliest-known frog-like creature, Triadobatrachus, lived about 250 mya in the early Triassic.

Like almost all terrestrial amphibians, adult frogs use not only lungs for gas exchange, but also their skin and the membranous lining of their mouths. (Lungless salamanders are an exception - as the name suggests, they must rely on their skin alone, which is very convenient for those researching amphibian gas exchange.) This reliance on transcutaneous respiration has meant that amphibians are very susceptible to harm due to to chytrid fungus infection, which severely damages the skin and markedly reduces the animals' ability to exchange O2 & CO2 with the atmosphere.

In addition, using your skin as a gas exchange surface means that you have to keep it moist. This means that we'd expect to find frogs only in environments that are humid and damp year-round, & in general that's the case. But there are always exceptions. and the desert rain frog is one of them. Breviceps macrops lives in one of the most inhospitable environments there is, a dry coastal strip of land in Namibia & South Africa. Hardly a place for a frog! It spends most of its time in burrows dug deep enough to reach into moist sand, but comes out at night when the air is cooler & more humid. While there's very little actual rain, moisture-bearing sea fogs roll in from the ocean on at least 100 nights each year, bringing some water to the habitat as the fogs condense onto dunes & vegetation - enough to allow these little amphibians to survive. (There's no actual tadpole stage in their life cycle; little froglets develop directly from eggs in the burrows.)

And like other amphibians, they vocalise to advertise their presence. I hesitate to say the sound is a croak. In fact, it drove my dog to distraction when I played the following clip.

I give you - 'the sonorous war cry of a very angry frog'.

 

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This was first posted over on Talking Teaching.

I’m always looking for interesting ideas that might spark student engagement. A couple of days ago this rap video popped up on the ScienceAlert FB page:

As you can see, it’s a fun post with a serious message & – I think – an excellent piece of science communication.

Anyway, then this happened:

BIOL102 chat re rap on FB

I’m really hoping that we can make this happen. It would be an excellent way to enhance interactions between undergraduate and grad students, and also with academics if they would like to be involved (& I’d hope at least some would!) It would give the grad students (& staff) an opportunity to communicate with a wider audience about the nature & significance of their work, and the undergrads who take part would gain some of the capabilities that they need in the world beyond university.

Here’s hoping!

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Today I heard that one of my favourite authors, Sir Terry Pratchett, had died (at the relatively young age of 66). And I cried. In his Discworld novels he created a world full of the most amazing characters, and while their voices - and through them his - will continue to speak to us, their adventures are done. I almost want to ask if anyone's checked for the sign that Granny Weatherwax used when she went 'travelling': I ate'nt dead.

Pratchett's books provided a compassionate, witty, literate & at times downright hilarious commentary on our own world: war, politics, racism, greed, kindness, cruelty, love, science, academia (his take on my own profession rang very true at times), and Death - who always spoke IN CAPITALS. 

In recent years Pratchett, who was living with (& I suspect enormously frustrated by) the effects of early-onset Alzheimers, had become an advocate for euthanasia. He wrote passionately & with great compassion on the subject. And he would probably have agreed with Death's opinion: that in his (to us untimely) death he was simply leaving early to beat the rush.

As he said himself (in Reaper Man):

No-one is actually dead until the ripples they cause in the world die away...

Rest in peace, Sir Terry, and may the ripples of your words continue to spread outwards for many years to come. 

 

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I've just spent an entertaining 10 minutes or so clearing out my spam folder. I don't go there often, but a student had asked why I hadn't answered their email & since I hadn't actually received one in the in-box, I thought I'd best check spam. (And there it was. General hint to students: really idiosyncratic email addresses will land you in spam, from time to time. Also, they can look a bit unprofessional on a CV.)

Apart from the amazing offers of money (if I'd only send a little money - a 419 scam - or alternatively my bank account details, plus PIN, I could be a millionaire! And retire to travel the world!!!), and people trying to sell me pipes and ball bearings, there seem to be an awful lot of people who are starved of social interactions and, dare I say it, romance? How else to explain the pitiful cries of Olga and Anna, who are 'nice girls' from Russia, just wanting a little companionship? They seem (from the subject lines of their emails) to be quite hurt that I haven't responded to their earlier pleas for the chance to get to know me better.

But it's slightly creepy to see so many people with such an interest in the quality of my love life!

And to those who asked (so many of you!) if I am the caring, tender gentleman of their dreams - ladies (if ladies you are), how wrong you are!

But more seriously, the sad thing is that someone, somewhere, will be responding to these scammers, and probably losing money - and equally worrying, potentially becoming subject to identity theft as well. A good rule of thumb here is, if it sounds too good to be true, it probably is! The next time you get one of these emails, check what snopes.com has to say on the subject, or visit the 419Eater archive.

But don't send money, your bank details, your photo. Because you won't find love, or money. You'll just make some nasty unscrupulous people even better off than they already are.

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Back in 2010 I wrote a post about bananas, following on from a Schol Bio question the previous year. As well as looking at the genotypes of modern bananas, I highlighted the fact that the original wild banana was not a particularly appetising object, with little flesh and a lot of large, hard seeds. Selective breeding for the win!!!

Anyway, it seems like at least one anti-GMO Facebook group has got a case of the vapours about 'GMO bananas', this being the only explanation some of its members could think of for the fibres that you'll often see in the skin of a not-completely-ripe banana when you twist & pull the stalk end. Kevin Folta picked this up in a blog post, noting the lack of knowledge of some of the commenters there (I haven't quite decided if the one about Morgellon's is a poe...) - but as Robert Sacerich notes, one of those commenters is giving an object lesson in how NOT to do science communication, & doesn't help the cause. 

And no, we have no GM bananas - at the moment. Sacerich points out that there's work in progress on developing GM plants that are resistant to the major threats to banana production (Black Sigatoka disease, Banana Bunchy Top virus, and bacterial infections). So such plants may well become a reality in the relatively near future.

But that will have nothing to do with the fibres that so concerned those anti-GMO commenters; they've always been with us & were apparently used in cloth production in Japan as early as the 1200s, a practice that's seen something of a recent resurgence. (I didn't know that! You learn something new every day.)

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And oh, how I wish I could say it was me who came up with that title!

But it wasn't; it was the BBC, headlining a fascinating article about how octopuses get it on.

It seems it's rather difficult to be a male octopus with mating on his mind. Like a female spider, his prospective partner may end up dining on him. 

In octopuses (& their relatives, squid, cuttlefish, & nautilus), males don't have a penis. Instead, they produce packets of sperm - spermatophores - which they must then pass the female using a specialised arm called a hectocotylus (which does contain erectile tissue). 

Squid practice a form of drive-by mating, slapping a spermatophore onto the outside of the female's body. It's pretty indiscriminate. In fact there was a report last year of a woman who ended up with squid spermatophores embedded inside her mouth, through eating parboiled squid - the hectocotylus still had some life in it.

Male octopuses, on the other hand, use that specialised arm to place their sperm packet well inside the female's mantle cavity, close to her ovaries. As you can imagine, this generally requires a certain amount of close contact, which is when things may get downright risky and in some species an unlucky male may finish his days as his beloved's meal. In one recorded incident

A female [Wonderpus photogenicus] used constricting as a form of fatal aggression to asphyxiate a male as part of apparent sexual cannibalism.

This image by Pierangelo Pirak is from the BBC article, and shows what's involved in octopode sex.

A beginner's guide to octopus sex (Credit: Pierangelo Pirak)

In some species the risk is minimised by having very long arms, and even by mating while the female is distracted, and in the blanket octopus the male simply detaches his hectocotylus & leaves it with his mate: an entirely reasonable tactic given the huge difference in size between male and female.

I was intrigued to hear that in some species there are 'sneaker males' - smaller individuals who may even hide that specialised mating arm in order to sneak in & mate with someone else's partner. This does not always end well either

The smaller males wait until a larger guarding male has left the den, then covertly mate with the female. As a result, they are called "sneaker" males. They have even been known to disguise themselves as females, hiding their hectocotylus to make a less threatening approach to a guarded female.

This sly tactic can occasionally backfire, as it did in an instance caught on film by Huffard. A sneaker male approached a burrow where he seemingly sensed a female was hiding. As he reached an arm in, an octopus emerged. But it was not the female: it was her guarding male. Unsurprisingly, this big male was not impressed by the sneaker male's attempt to insert a hectocotylus into his mantle.

And a somewhat mind-boggling fact to end on: the spermatophore of a male Pacific octopus is almost a metre long, and may take an hour to transfer to the female. I think it goes without saying that this must be one of the 'friendlier' species!

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Recent Comments

  • Alison Campbell: At least he doesn't infest the place with earworms! read more
  • herr doktor bimler: Further discoveries! http://eusa-riddled.blogspot.co.nz/2015/04/casting-aspersum.html You're letting that Thunder commenter past the read more
  • Alison Campbell: I love it that Riddled made this stuff up a read more
  • ifthethunderdontgetya™³²®©: I'm glad you were able to set those Riddled guys read more
  • Alison Campbell: For which one is glad - after all, impressionable young read more
  • herr doktor bimler: quite why putting protein molecules (which are highly unlikely to read more
  • Alison Campbell: I can't help thinking a) that there's one born every read more
  • herr doktor bimler: The species has now apparently been reclassified as Cornu aspersum. read more
  • Alison Campbell: Indeed, it is a thing. But you are in good read more
  • herr doktor bimler: So 18 months ago I had a lot of gastropod read more