Extraordinary Embryo of the Week

OK. So I have two weeks of embryos to catch up on... blame the Christmas madness for my neglect of the blog!

First up, a sea urchin embryo, from George Watchmaker at Livermore, CA, USA.



Sea urchins were one of the first model systems in developmental biology, and the first species in which sperm cells were shown to fertilise the ovum! Nowadays they're often used by groups doing evolution and development (evo-devo) studies.

Now for the second picture: this time, it's a human!



This embryo is just starting to grow limbs, you can see one of the limb buds as a big blob coming off the side of the embryo. Even now, when it looks like a shapeless blob, the limb already has all three axes determined: dorsal-ventral (back to palm of hand), anterior-posterior (thumb to pinky - even though the digits haven't yet formed!) and proximal-distal (shoulder to fingertip). I'll write a more detailed post on limb development (and what can go wrong) sometime in the future, because it's a really great example of organ development in an embryo.


I hope everyone had a great Christmas! I can't believe it's almost 2010. I have to start thinking about my New Year's resolutions... eek

Extraordinary Embryo of the Week

Mondays are tough. It seems to be a universal truth.

My solution? Brighten our Mondays with a beautiful embryo image!

Of course, for my first Extraordinary Embryo, I had to choose Xenopus laevis, my current weapon of choice (slash model organism).

I've had this image on my screensaver for a while now, and while it's very simple, it's also quite beautiful. It's from Michael Klymkowsky at the University of Colorado Boulder.



As you can probably tell, they're both quite early stage embryos - they're still just balls of cells. The embryo on the left is at a later stage than the one on the right - you can see that it has a lot more cells.

There's something about these ball-shaped embryos that really makes me smile. Why? I guess because they make me think about what's still to come.

At some point they stop being balls and start to become animals. The cells in these balls move and grow and change, and they do so in an organised way. Cells on one side "know" that they're on that side, and act accordingly. Every cell is an individual, there is no "boss-cell" giving orders and telling the rest where to go. Yet somehow, these individuals work together, dividing and differentiating and migrating... To produce an animal.

And I think that's pretty amazing.

Science cookies

Inspired by these beautiful cookies, my friends and I made a bunch of geeky science-themed cookies today!

Here is one of our (far inferior) electrophoresis gel cookies...



And then we got a little carried away with other geeky things too...



Including the animals we work on: Xenopus laevis, Oncorhynchus tshawytscha, and Ovis aries




Sequencing electropherograms: We designed sequences that spelt out our names in one-letter amino acid codes!




And little models of cells that include features such as a nucleus, rough ER and smooth ER, mitochondria, and Golgi.





I don't think I'll need to eat for a month after all these...

There's probably no god...

The NZ Atheist Bus Campaign was launched yesterday. I like the campaign, it's punchy while not being aggressive. The Campaign is trying to raise an initial $10,000 to kick off their advertisements in Auckland, Wellington and Christchurch. When I donated yesterday, the total raised was only $220, but today it's over $4,000 - I think this is a consequence of publicity from being featured on Sunrise and Stuff.co.nz this morning.

As expected, the comments on these stories are riddled with the same tired old arguments coming from mis-informed believers. Here's a summary of their content:

- "There's PROBABLY no god..." Ooh look the atheists admit that they don't even know. Thus, God exists. Oh and he loves you, right?

- Saying "probably" means that you're agnostic, not atheist. Stupid atheists. They don't even know what they stand for. I love to talk about concepts that I'm clearly ignorant of. It makes me feel important and clever.

- You say god doesn't exist, but what if he does???! That's an awfully big risk to take??!! Thus, He exists. In other words, I only believe in Him because I'm a coward and I'm hedging my bets.

- (Often in combination with the previous statement): You'll realise you're wrong when you're dying. Your very soul will cry out to Jesus.

- Moan moan moan, atheism doesn't have a stigma, religion does! In other words, I get picked on for being a believer. You meanies. Stop picking on me.

- There's a uproar when us believers display religious symbols in public, but you evil atheists are allowed bus ads? Outrageous!
(OK, I really only have one reply for this. Case study: EASTER AND CHRISTMAS, ANYONE???)

- This is so unfair. Why haven't they said "There's probably no Allah". Christians, are like, soooo picked on. I'm ignoring the fact that Allah is still a "god", and thus is probably included in the slogan anyway. Mainly because I like to pretend that I'm suffering and persecuted for my beliefs, because then I'm like Jesus. Right?

- Any combination of: This is pointless. I don't give a shit. I don't know what they're trying to achieve. It's a waste of money. This doesn't seem important to me. I don't see how this is going to benefit anyone. I don't understand how to tie a shoelace can anyone help me out?

- Quoting bible verses. God loves you. He is so good, and loving, and he will forgive you for being an evil atheist, once you repent and stuff. Sickening bullshit. (For some reason I always hear a simpering whispery voice whenever I read these types of comments)

- Quoting bible verses. You're all going to hell. God will strike you down. I can't wait for you to burn in hell. Oh God loves you, but he'll still send you to the pit of fire.





I'm tired.

UPDATE: Almost up to $6,000 now! Go donate: If the donations keep climbing at this rate, we'll have bus ads all over NZ in no time. It would be nice to have them in Dunedin, which isn't in their current plan yet.

We are made of star stuff

I'm currently reading the very cool book Death From The Skies!, by Phil Plait, which outlines a bunch of end-of-the-world scenarios and then talks about the science behind them. Phil's an astronomer, and a fantastic writer - I've been a fan of his ever since I was about 15 years old, when I discovered his hilarious Bad Astronomy website (his review of the movie Armageddon still makes me chuckle).

Death From The Skies! is one of those books where you just end up thinking "wow, science is so darn cool!". Being a bit of a geek for pretty much my entire life, I thought I knew a reasonable amount about astronomy and astrophysics, for someone who's a non-specialist. But every chapter of Death From The Skies is full of things that I haven't encountered before - and many of these tidbits are extremely cool.

One particular chapter on supernovae is full of "wow-facts". In this chapter, Phil talks about the processes of fusion in the core of massive stars. Our own sun fuses hydrogen nuclei to produce helium, but more massive stars can produce other elements by fusion, once their hydrogen supply has run out. Massive stars produce, in this order, carbon, neon, oxygen and silicon; and the most massive stars in our universe have such tremendous pressure and heat at their core that they can produce iron. These stars, however, do not have long to live once they are producing iron, and will soon explode in a furious cascade of events that we call a supernova.

The early universe contained only three elements: hydrogen, helium, and a little bit of lithium. Nothing else. Then supermassive stars started to form, and began creating heavier elements from the lighter ones, right up to iron, then exploded. The explosions of these stars triggered the formation of new stars... and the cycle continued.

I'll leave you with (what I think is) the most striking paragraph of this chapter:

When you cut your finger and a thin rivulet of blood seeps up into the slice, the red color you see is due to hemoglobin, and the key factor in that molecule is iron. That iron was forged in the heart of a supernova.

As Carl Sagan told us: We're made of star stuff.

http://www.youtube.com/watch?v=XGK84Poeynk&feature=player_embedded