The plant in you (and vice versa)

 From: Double-fertilization, from myths to reality, a review from 2007 -

It is becoming gradually clear that although plant and animal kingdoms diverged more than 1 billion years ago, similar mechanisms govern sexual reproduction in both kingdoms. The review by Márton and Dresselhaus (2008) outlines some of these parallels. The current idiosyncratic nomenclature used to designate plant reproduction has obscured the parallels that now become apparent between plants and animals. It is likely to be the time to rethink the designation of each actor of the reproductive process such that the literature in the field becomes relevant to a broader readership working in the field of reproductive biology.
The  Márton and Dresselhauspaper referred to is A comparison of early molecular fertilization mechanisms in animals and flowering plants.

Forbidden experiments

 Mothra's larval form destroying the Tokyo Tower in the movie Mothra from 1961.

In the Fantastic Four comics Dr Doom was expelled from Empire State University for carrying out 'Forbidden experiments'. The experiment in question involved contacting the dead so maybe that's not that surprising, but I was always amused by the notion that a University might have a big list of 'Forbidden experiments'. Ah yes, item number 147, 'Contacting the Dead', right after number 146 'Reanimating the Dead'.

Anyway, I was reminded of that when I took a quick look for some papers on insect gigantism and came across this recent review paper Atmospheric oxygen level and the evolution of insect body size, where they mention several experiments where people have selected for insect gigantism over many generations under high oxgyen conditions in the lab.

The effects of hyperoxia on growth and body size are less consistent and often nonlinear (Harrison et al. 2009). Body size increases in the giant mealworm, Z. morio (27% O₂; Harrison et al. 2009) and in the scarabaeid beetle C. texana (40% O₂; Harrison et al. 2009).

I'm pretty sure 'Creating Giant Insects' would also have been on empire State's list. Did Mothra not teach us anything?

But the answer to our question of what other giant insect (and other arthropod) fossils have been found is:

Among insects, gigantism in the Permo-Carboniferous has also been reported for Ephemeroptera, Diplura, Thysanura and the extinct order Paleodictyoptera (Briggs 1985; Kukalova-Peck 1985). Arthropleura, a group related to modern day millipedes, reached upwards of 2 m in length, almost six times the size of any extant millipede. 

So no, no Lepidoptera, you'll just have to make do with Mothra.

Flesh-fly

Today's featured picture of the day on the Wikipedia home page is this splendid picture of a flesh-fly:

Flesh fly, from the Sarcophagidae family "blowing a bubble". One explanation for this behaviour is that it concentrates the fly's meal by evaporation. The diet of the flesh fly is very high in water content. The fly regurgitates the liquid portion of the food, holds it whilst evaporation reduces the water content and the fly then swallows a much more concentrated food meal without the water content. This continues until sufficient amount of liquid is left for the fly.

Rubbish flyers

R. L. Nudds, G. J. Dyke. Narrow Primary Feather Rachises in Confuciusornis and Archaeopteryx Suggest Poor Flight Ability. Science, 2010; 328

The fossil birds Archaeopteryx and Confuciusornis had feathered wings resembling those of living birds, but their flight capabilities remain uncertain. Analysis of the rachises of their primary feathers shows that the rachises were much thinner and weaker than those of modern birds, and thus the birds were not capable of flight. Only if the primary feather rachises were solid in cross-section (the strongest structural configuration), and not hollow as in living birds, would flight have been possible. Hence, if Archaeopteryx and Confuciusornis were flapping flyers, they must have had a feather structure that was fundamentally different from that of living birds. Alternatively, if they were only gliders, then the flapping wing stroke must have appeared after the divergence of Confuciusornis, likely within the enantiornithine or ornithurine radiations.

Or, as ScienceDaily summarized: The evolution of flight took longer than previously thought with the ancestors of modern birds "rubbish" at flying, if they flew at all, according to scientists.

Phagocytosis

This video, taken from a 16-mm movie made in the 1950s by the late David Rogers at Vanderbilt University, shows a neutrophil chasing down and consuming bacteria. Although some or all of the movement of the bacteria may simply be due to Brownian motion the movement of the neutrophil is clearly directed, in this case by chemical gradients. There's another nice video showing neutrophil chemotaxis here.

Unfortunately internet memes run a strong and I immediately thought of the following BoingBoing post - Adding the Benny Hill Theme to Anything Makes it Funny. So it was no surprise to find someone had already done that.

Dog's noses

With regard to the post below, if any of you are members of alternative rock bands then I think 'Phineas Gage was not an asshole' would be a great name for a song.

And now for something completely different.....

When a dog sniffs, he uses a different route of airflow than for normal breathing. A structure just inside the nostrils called the alar fold, opens allowing air to flow through the upper area of the nasal passages. A bony pocket traps odor molecules and they are dissolved in the mucous covered scent receptors where signals of this chemical change travel from the receptor along the olfactory nerve to the olfactory bulb at the end of each nasal passage.

When the dog exhales, the alar fold closes off the upper part and pushes air down and out through the slits on the side of the nose, which stirs up even more scent particles.

Odor molecules emanate from the source in a cone shape. Depending on environmental factors, odor molecules will be denser at the source and thinner as they disperse into the air. Scent detection dogs will scan this scent cone as they trail the source, often making a ‘whuffing’ sound.

From the Cadaver Dog Handbook by Andrew J. Rebmann, Marcella H. Sorg, Edward David

(Scooter can make 'woofing' sounds but I don't think that's what they are talking about.....)

What are we good at.? (ans=sweating)

There's been a resurgence of interest lately in what led to the evolution of bipedalism in humans and the importance that running may have had in our evolutionary past. From Christopher Moore's best selling book 'Born to Run' to cover stories in the prestigious journal Nature (eg Endurance running and the evolution of Homo), running, especially barefoot running and endurance running, is quite the hot academic topic these days.

Unfortunately the same cannot be said for the actual sport of endurance running. I would guess that only a tiny handful of Americans are aware the right now the world 24 hour running championship is going on in Brive, France. The race started about 12 hours ago and will continue for another 12. You can get live updates here if you are so inclined. There is both an individual race and also a team event, with the combined distances of the top 3 runners counting for the national championship. At the last check the USA men's team and the Japanese men's team were separated by a meter! Men:JPN 421.872km, US 421.871km

The lead runners are averaging about 12km/h or 7.5 mph. That's 8 minutes per mile- hardly a slow jog. And they have been doing that for 12 hours..... with 12 more to go......

I find these performances literally amazing. What is equally interesting is that the participants don't look like freaks. They aren't muscle bound, neither are they all incredibly thin (one of the US team was over 300lbs until recently and still tips the scales around 200), they aren't all short and they aren't all tall, they aren't all young and they aren't all old - they actually look like a cross section of people you might find anywhere. (I like this picture - the tiny Russian lady on the left is 61 !)

Most animals have to pant to lose heat. Animals cannot pant and run simultaneously, limiting how long they can run before they have to stop to pant and cool down. Humans can lose heat by sweating so we can run for much, much longer. But sweating loses water and salt. So the good ultra-runners have to be exceptionally good at maintaining their fluid and salt levels.

In many ways this race is the world homeostasis championship.

Update: Exciting finish with the USA men's team holding onto third place and Scott Jurek completing 165.7 miles to beat the American record. The men's winner, Shingo Inoue from Japan, completed 170 miles and the Women's winner, Anne Cecile Fontaine of France, completed 149 miles. The second place finisher for the US (12th overall) Michael Henze finished with a 22 minute last 5k...... The tiny Russian lady above completed 117 miles.

Orchid bee trade-off

Orchid bees use their extraordinarily long tongues to drink nectar from the deep, tropical flowers only they can access. Researchers have long suspected that this kind of exclusive access came with a mechanical cost. According to common sense and a classic law of fluid mechanics, it's just plain hard to suck thick, viscous nectars up through a long straw.

A paper in The American Naturalist confirmed this prediction for the first time in 2007: orchid bees with long tongues suck up their nectar more slowly than bees with shorter tongues.

Scaling of Nectar Foraging in Orchid Bees

Weekend video

For most of human evolutionary history, before the advent modern running shoes, humans ran either barefoot or in minimal shoes. A comparison of the biomechanics of habitually shod versus habitually barefoot runners suggests that running barefoot is not only comfortable but may also help avoid some impact-related stress injuries. On the cover, the feet of Kenyan adolescents who have never worn shoes and run up to 20 km a day. Their feet are healthy and strong - and until recently, everyone’s feet looked like this.

I was going to leave this until next quarter but since being on the cover of Nature last week barefoot running is attracting even more attention from the media. Nature is actually a little slow to this bandwagon - just this week I've caught two CCS students indulging in barefoot escapades.

Nature have a nice series of short videos that illustrate some of their papers.



This actually reminds me of a story I read recently, in Wired magazine I think. Some researchers were interested in using force platforms to help rehabilitate stroke victims by giving them feedback on balance and forces. The type of force platform that would typically be used, like the one used to calculate the forces on the foot in the study above, can cost well over $10,000. Looking for a cheaper alternative they dismantled the balance board available for skateboarding and balance games on the Nintendo Wii system. They found the accelerometers and strain gauges more than adequate. Thanks to the Internets I can confirm that this half remembered second hand story is actually true.

Carrot power

Many people believe that carrots are good for their eyesight. There is a germ of truth in this in that carrots are indeed a good source of vitamin A, and vitamin A is required for, among other things, correct functioning of the visual system. However just because they are required for correct functioning does not necessarily mean that eating more of them will improve your vision. The origin of the myth that carrots are good for your eyesight dates back to World War II and the Battle of Britain that occurred in 1940 and marked a turning point in the war. The Battle of Britain refers to the air battle between the German and British air forces for air superiority. A German victory would have permitted a cross channel invasion of England.

Although the principles of Radar had been known for a long time it was British scientists who produced the first working system, enabling ground controllers to direct British planes to intercept German planes in poor visibility and at night. In order to maintain their advantage the British spread the rumor that their pilots were being successful because of their extraordinarily good eyesight. A feat that was achieved by the mass consumption of carrots. This rumor affected both the Germans and the British. Due to the blackout at night and the frequent requirement to move to air-raid shelters people were keen to improve their night vision and carrots were readily available from allotments and gardens.

I do not know whether the Germans fell for this story. There are a few suspicious parts to it that may not have been fully understood at the time. Or maybe this was a sneaky part of the plan, to encourage German pilots to poison themselves with large amounts of Vitamin A. As Claudia pointed out today, if you want to propose ingesting large amounts of a vitamin you might be better off picking one that is water, rather than fat, soluble. As vitamin A is fat-soluble, disposing of any excesses taken in through diet is much harder than with water-soluble vitamins B and C. As such, vitamin A toxicity can result. This can lead to nausea, jaundice, irritability, vomiting, blurry vision, headaches, muscle and abdominal pain and weakness, drowsiness and altered mental status. Too many carrots will also cause you to turn orange from the accumulating beta-carotene. Another good source, in fact a much better source, of vitamin A is liver. Too much liver is even worse and can kill you quite quickly as Arctic explorers who were reduced to eating polar bear and sled dog liver discovered. Polar bears have very high concentrations of vitamin A in their liver and the native Inuit were well aware of this fact:

After killing a bear, the Inuit ate the meat and used the fur to make warm trousers for men and kamiks for women. An average polar bear would yield three pairs of trousers and one kamik. The only part of the bear that was not used was the liver. This was immediately thrown out, as it could make even the sled dogs violently ill.
From Polar Bear International.

Fetal hemoglobin and sickle cell anemia

Speaking of hemoglobin, I find it amazing that newborn babies have a different type of hemoglobin, fetal hemoglobin, that will be completely replaced by the adult form within a few weeks of birth. The fetal hemoglobin binds oxygen more readily than the adult form, thereby allowing the developing fetus to obtain access to oxygen from the mother's bloodstream via the placenta. The reactivation of fetal hemoglobin synthesis in adults has been used to treat sickle-cell disease since 1995.

When fetal hemoglobin production is switched off after birth, normal children begin producing hemoglobin A. But children with sickle-cell disease instead begin producing a long, slender form of hemoglobin called hemoglobin S. This variety of hemoglobin causes red blood cells to change their shape from round to sickle-shaped, which have a greater tendency to stack on top of one another and crowd blood vessels causing a variety of problems. If fetal hemoglobin remains the predominant form of hemoglobin after birth, however, these problems can be reduced.

Nature Medicine covered the breakthrough discovery of fetal hemoglobin promoting drugs such as hydroxyurea in 1995: Sickle cell paths converge on hydroxyurea.

Icefish

In a perfect segue from the post below, if you do go swimming in Antarctic waters the picture to the left shows one of the strange creatures you might come across - the Antarctic Icefish (Chionodracus hamatus).

This fish lives in waters well below freezing and only just above the freezing point of salt water (about -2C). If you went swimming in water this cold wearing a Speedo then, as Lewis Pugh discovered, your cells would freeze and consequently suffer quite serious damage. If you stayed in more than a few minutes you would die.

So how does the ice-fish survive? The answer is that it has evolved an antifreeze glycoprotein in its blood. The glycoprotein molecules bind to ice crystals and prevent them from growing to a size where they would damage the fish’s body. Although this has been known since the 1960's work continues in this area, for example this paper, One-pot synthesis of cyclic antifreeze glycopeptides from earlier this year.

Of greater relevance to today's lecture is the strange clear, almost transparent, appearance of the fish. They are sometimes referred to as 'white blooded' because their blood contains no hemoglobin. Lots of antifreeze and no hemoglobin! So how do the fish survive? Well, remember that solubility of oxygen increases as temperature decreases. So the frigid waters of the Antarctic have considerably more oxygen in solution. Furthermore the blood plasma can hold more oxygen at low temperatures (for the same reason) and the animal's metabolic rate is lower. So the icefish can deliver sufficient oxygen to their cells in the plasma without requiring hemoglobin as a specific oxygen-carrying molecule. Cool.

It is not known whether there is any link between these two phenomena. It is not actually necessary for there to be a selective advantage to the loss of hemoglobin to explain its dissapearance (remember genetic drift?) but I can't help but wonder whether there is a link. For example if the presence of hemoglobin reduces the efficiency of the antifreeze.

If you want to read more then this 2006 paper will get you into the literature: When bad things happen to good fish: the loss of hemoglobin and myoglobin expression in Antarctic icefishes.

More Llama

Hopefully some of you braved the hippies to see the Dalai Lama today. In other Llama related news BoingBoing had a great article today on how Llamas are involved in the war on terror - Llamas: Nature's Cute & Fluffy Crusaders Against Bioterrorism.

Llama blood may one day be able to help soldiers, scientists and city officials set up an early-warning system against the tiniest weapons of terror--biological agents like anthrax and smallpox. Authorities have long worried that, were these diseases to get loose, it would be difficult to know anything was wrong until innocent people started dying. Llama blood might provide a better detection method.

How? Antibodies, the tiny molecules that float around in the bloodstreams of people and almost all animals. Antibodies keep a sort of "memory" of all the diseases, allergens and other foreign invaders your body has come into contact with. If the same infiltrator shows up again, the antibodies can match it up with their stored records and immediately know how to fight it.
For a while now, scientists have used genetically altered antibodies to help ID and treat specific diseases. But these techniques always ran into a common problem: Antibodies were just too delicate to be of much use outside a lab or hospital setting. Enter the llama.

According to news stories about the research, llamas have extraordinarily tough and hardy antibodies, capable of sustaining exposure to temperatures as high as 200 degrees F. This discovery gave the researchers the idea to develop sensors, based on llama antibodies, that could be distributed to soldiers in a war, or around cities back home. Modified to be specifically on the lookout for likely-to-be-weaponized diseases, these sensors could pick up signs of a biochemical attack before victims started arriving at the hospital.

The 5 ages of the brain

New Scientist magazine has an interesting article this week about the brain, The five ages of the brain

From 'The Adulthood' section
So you're in your early 20s and your brain has finally reached adulthood. Enjoy it while it lasts. The peak of your brain's powers comes at around age 22 and lasts for just half a decade. From there it's downhill all the way.

This long, slow decline begins at about 27 and runs throughout adulthood, although different abilities decline at different rates. Curiously, the ones that start to go first - those involved with executive control, such as planning and task coordination - are the ones that took the longest to appear during your teens. These abilities are associated with the prefrontal and temporal cortices, which are still maturing well into your early 20s.

Episodic memory, which is involved in recalling events, also declines rapidly, while the brain's processing speed slows down and working memory is able to store less information.

So just how fast is the decline? According to research by Art Kramer, a psychologist at the University of Illinois in Urbana-Champaign, and others, from our mid-20s we lose up to 1 point per decade on a test called the mini mental state examination (see graph). This is a 30-point test of arithmetic, language and basic motor skills that is typically used to assess how fast people with dementia are declining. A 3 to 4 point drop is considered clinically significant. In other words, the decline people typically experience between 25 and 65 has real-world consequences.

That all sounds rather depressing, but there is an upside. The abilities that decline in adulthood rely on "fluid intelligence" - the underlying processing speed of your brain. But so-called "crystallised intelligence", which is roughly equivalent to wisdom, heads in the other direction. So even as your fluid intelligence sags, along with your face and your bottom, your crystallised intelligence keeps growing along with your waistline. The two appear to cancel each other out, at least until we reach our 60s and 70s.

There's another reason to be cheerful. Staying mentally and physically active, eating a decent diet and avoiding cigarettes, booze and mind-altering drugs seem to slow down the inevitable decline.

Although some might find this depressing I was really quite excited by this article. I'd assumed I was getting senile MUCH quicker than this......

Costs of changing sex

In class we looked at certain monoecious plants that are able to change sex as they grow - and at an explanation for why this should occur and why the change should always be from male to female. A few animals can also do this sequential hermaphroditism but it is relatively rare as a strategy. In a recent paper in Am Nat two Yale scientists ask why the strategy isn't more common. One explanation would be that the costs of changing sex outweigh the benefits. The conclusions of their study are not buried deep in the paper but right there in the title:
Costs of Changing Sex Do Not Explain Why Sequential Hermaphroditism Is Rare

The RR Warner in the acknowledgements and numerous citations is, of course, UCSB's Bob Warner who works, amongst other things, on sequential hermaphroditism in fish

Also, if you'd like to read the original Nature paper describing the Papaya story I mentioned you can find it here:
A primitive Y chromosome in papaya marks incipient sex chromosome evolution

Extreme longevity in proteinaceous deep-sea corals

From last week's PNAS (Proceedings of the National Academy of Sciences):
Extreme longevity in proteinaceous deep-sea corals

The "gold coral" Gerardia and the black coral Leiopathes both grow several meters tall at depths of up to 500 meters on the Hawaiian seabed. They grow when each succeeding coral polyp secretes a thin layer of calcium carbonate onto the base of the "cups" in which they live.

Previous studies had guessed their age at a few hundred years but the PNAS study by Brendan Roark and colleagues argues that what were previously counted as annual growth rings actually take much longer to form. Using high-resolution radiocarbon dating, Roark's team studied the corals' outermost shell for traces of "bomb carbon" - radioactive carbon produced during nuclear tests in the 1950s. They found it was present in only the upper 10 micrometres of the coral skeleton, suggesting this tiny slice took decades to build up. Further carbon dating of layers down at the corals' base revealed the oldest Gerardia to be about 2742 years old and the Leiopathes 4265 years old.

Stupid octopus tricks

Well, since I'm not the only one feeling the cephalopod love, here's one more for you. As was noted, octopuses are notorious for escaping from tanks since they are agile, clever and have no rigid skeleton - allowing them to squeeze through practically any gap that they can squeeze their brain through.

This is actually more than just a stupid pet trick since it really helps to remind you that, in water at least, a hydrostatic skeleton, like that of an octopus, can be very impressive and allow sophisticated, rapid and powerful movement.

Octopuses in disguise

Once you start posting cephalopod videos it's hard to stop. This one is a nice overlap between diversity and next quarter's physiology though.

Getting a paper published in science as a grad student. Excellent.
Giving it a cool title: Underwater Bipedal Locomotion by Octopuses in Disguise. Even better.
Capturing the whole thing on video. Priceless.

Cephalopod star

There are a lot of amazing octopus videos around. Here's the most famous camouflage one:


Of course as biologists we want to look a little deeper. The cool bit is that it gets even more amazing as you think about it more closely. As PZ Myers pointed out on his blog, the octopus needs to do four things to achieve this trick:

1. It needs good visual system. In order to match the background you need to be able to see it. To match it well, you need to see it well.
   
2. To pull off the fast change you need a fast connection from the brain to the color changing organ.
3. Speaking of which, yes, the octopus needs organs that can change color. Cephalopods have tiny, discrete sacs of pigment scattered all over their body, each one ringed with muscles that can close the sac to conceal the pigment, or expand the sac to expose the pigment.
4. Finally, the octopus needs a set of rules, an algorithm, so it can translate what is sees with its eyes into a visual pattern that hides the animal.
   

For more information check out the website of Roger Hanlon at Woods Hole Marine Biological Laboratory. The New York Times had a nice article on his lab recently, Revealed: Secrets of the Camouflage Masters. For a more scientific, but still very accessible treatment, see Cephalopod dynamic camouflage, in Current Biology.

Things Darwin would not say

In honor of the 200th anniversary of Darwin's birth, New Scientist magazine had a competition to come up with the best 'Thing you would never have heard Charles Darwin say about evolution.' Out of 900 entries the winner was:
'Finches eh? Seen one, seen 'em all'

Also in New Scientist this week The Last Word, where readers send in questions and then others submit answers, has:

I have always been fascinated by evolution, and while I can usually see why and how certain characteristics evolved in different species, I'm confused by whales and dolphins. How did their breathing holes evolve, bearing in mind their ancestors were land mammals?

You can see the answers submitted to date here.