Zebrafish

Some observations on working with zebrafish:

Their vision isn’t as reliable as I thought. They would try like there’s no tomorrow to swim through the Plexiglas wall when there’s a hold only a few inches over. If I want to continue my experiments without having an aneurysm, I’ll have to make a few changes.

1 – The walls will have to be marked up opaque so that the fish don’t keep trying to swim through them.

2 – Since they have trouble navigating the single chamber, I’ll have to use plastic sheets to funnel them toward the door.

3 – I have a new set of tests to run. Is it the food that draws the fish into the food chamber, or is it the pheromones of the “social reward” of other fish that is repulsing the fish away. Once I get back to school after Thanksgiving, looks like I’ve got my work cut out for me.

Jaekelopterus

If you’ve been following Lio lately, you know he has a new arthropod friend, rescued from the dinner pot.

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Unfortunately, Lio missed the big news.

The fossil record has yielded various gigantic arthropods, in contrast to their diminutive proportions today. The recent discovery of a 46cm long claw (chelicera) of the pterygotid eurypterid (‘sea scorpion’) Jaekelopterus rhenaniae, from the Early Devonian Willwerath Lagerstätte of Germany, reveals that this form attained a body length of approximately 2.5m–almost half a metre longer than previous estimates of the group, and the largest arthropod ever to have evolved. Gigantism in Late Palaeozoic arthropods is generally attributed to elevated atmospheric oxygen levels, but while this may be applicable to Carboniferous terrestrial taxa, gigantism among aquatic taxa is much more widespread and may be attributed to other extrinsic factors, including environmental resources, predation and competition. A phylogenetic analysis of the pterygotid clade reveals that Jaekelopterus is sister-taxon to the genus Acutiramus, and is among the most derived members of the pterygotids, in contrast to earlier suggestions.

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This isn’t some casual graspy sort of claw, either—it’s a great spiky wicked looking claw, with pointy daggery bits sticking out that make it look like some medieval weapon of terror.

This is a much more Lio-like creature than the dainty little bug in the cartoon. I wouldn’t mind having one of these for a pet myself! It’s too bad they’ve all been dead for 390 million years.

Braddy SJ, Poschmann M, Tetlie OE (2007) Giant claw reveals the largest ever arthropod. Biology Letters doi:10.1098/rsbl.2007.0491.

Stem cell breakthrough

Blogging on Peer-Reviewed Research

A recent discovery in stem cell research is no minor event: researchers have figured out how to reprogram adult cells into a state that is nearly indistinguishable from that of embryonic, pluripotent stem cells. This is huge news that promises to accelerate the pace of research in the field.

The problem has always been that cells exist in distinct states. A skin cell, for instance, has one set of genes essential for its specific function activated, and other sets of genes turned off; an egg cell has different patterns of gene activation and inactivation. Just taking the DNA from a skin cell and inserting it into the egg cell isn’t necessarily going to create a functional egg cell, because genes essential for egg cells may be switched off in the skin cell DNA, and we don’t know how to specifically switch them on. The process of somatic cell nuclear transfer has been hit or miss for that reason, with very high failure rates—scientists are basically trying to make the right configuration of genes switch on by giving the nucleus a good hard kick, and hoping that something in the cells will reconfigure the pattern of gene activation into something appropriate.

What the discovery by Takahashi et al. accomplishes is to reveal how to specifically switch on the right pattern of genes for a pluripotent stem cell. They have discovered the reset button for mammalian cells: a simple trigger that puts the cells in the right state to become anything else.

[Read more…]

Shhh. The creationists are listening.

It’s a little odd to find myself cited in a Polk County, Florida newspaper as evidence that their pro-ID activities have received “national attention.”

Otherwise, it’s an article that testifies to the inevitability of a conflict. A majority of the school board members in Polk want to insert creationism into the curriculum, and they’ve got a few supporters in the schools.

…an eighth-grade science teacher at Union Academy in Bartow spoke in favor of intelligent design, a belief that living organisms are so complex that they must have been created by some kind of higher force.

“When you talk about laws in nature it shows some order or design,” said Lawrence Hughes, who has taught at the academy for 16 years. “The laws of nature don’t support change from one organism to another organism.”

What utter tripe. What we see in nature is that the boundaries are extremely fuzzy, and that there are no “laws of nature” that block change. Perhaps Mr Hughes would like to state what these laws are, exactly?

A few people are arguing strongly on the side of reason, but one gets the impression that the creationists have made up their minds and are spoiling for a fight.

Road trip!

One of our Minneapolis Christian talk radio stations, KKMS, is organizing a trip.

Join Jeff & Lee as they travel with Heartland Tours & Travel to the Creation Museum in Cincinnati, Ohio! Jeff & Lee will be doing a live broadcast from the museum, and you can be there to see it all happen! of course, there will be other great stops along the way – Chicago (and famous Chicago pizza), the Wisconsin Dells with it’s huge waterpark, shopping at the Tangier Outlet Mall and more! this is a tour that will inspire your faith and make lasting family memories.

Don’t you think they could really use a scientific guide to go along with them? Call me, Jeff & Lee — I’m willing to waive my usual fee to accompany your bus as a consultant.

I am rather amused that what will inspire their faith is Chicago pizza, a tacky amusement park, and shopping.

(h/t to Eva)