zyncod

Yeah - I agree. The "I pledge allegiance.." part bothers me a lot more than "under God." It smacks of state-sponsored indoctrination.

Not really very possible. If you've ever heard of people doing stuff with ancient DNA (usually meaning less than one million years old), you'll be aware that to even do PCR of a short fragment is nearly impossible. I got my head chewed off for even opening a drawer that had pipettes in it that people used for ancient DNA. The chances of being able to reconstruct the millions of base pairs required to build a dinosaur would be vanishingly small. My old adviser wrote a book about precisely why this won't work - "The Science of Jurassic Park."

I did it about a year ago. I think it was ficoll/hypaque. Fairly simple, but MACs would probably work better.

Mmmm. I'm sure you agreed with his books, but that probably had very little to do with your veganism. I have yet to meet one vegan that believes that GMOs are a good thing or that Adam Smith was right about the "invisible hand." You really aren't an extremist, you're part of a very large peer group that operates in ideological lockstep, and the peer group probably is responsible for at least 90% of your beliefs. Not a bad thing (nobody's really an "individual"), but definitely vegans are no (longer) an extremist group. ALF is an extremist group, but that's another thing altogether. Personally, I'm a vegetarian vivisectionist (literally). A lot of my friends (also of the vegan/vegetarian persuasion) are of the mentality that I'm somewhat of a murderer, but I see a difference between research animals that are treated as humanely as possible and whose deaths very much help humanity, and factory farm animals, whose deaths help somebody have a cheeseburger. Oh, and I'm also a neo-Marxist, so I'm guilty of being in lockstep to some extent as well.

Right! This is "grown-up" time! It's time to stop playing around with evolution and fossils and radiometric dating and start getting to the real issues, like how an omnipotent being made us some undeterminate time ago for some undeterminate reason...... Sooooo - what do we do now? I mean, "science" is apparently for kids. Ooohh! I know! Let's all convert to Christianity and start getting those calluses on our knees. Look, I would expect a little bit of abuse if I went on Hyperradicalhomophobicevangelists.com and started talking about how everybody's mom used to be some hairy gorilla. If you go to Scienceforums.net and start spouting the equivalent of "Pink marshmallow fairies built the Great Wall of China," you've gotta expect some abuse too.

I read the rest of that cartoon. Do people really think that Jesus is holding atoms together?

Oh, I'm sorry. You're really going to get killed over the utter inanities that you've posted here. I'm not going to argue these things - there are plenty of people here that will probably post step-by-step responses that you will completely ignore. But the post is hilarious - I would love to meet this hypothetical evolutionist. Unlike all sentient beings we have encountered up til now, he/she seems not to be a vertebrate.

This is not how you see what biologists are saying about microcephalin. The way that you actually see what they are saying is to wait for further papers to come out about this topic. I can understand the public's complete lack of patience, but you've all waited thousands of years even to hear about microcephalin. You can wait a year or two longer to get some rational discourse about this topic.

Rrrrghh. The word "meme" means absolutely nothing. It's a fashionable term for something that has existed throughout the history of human language. Everybody knows what a meme is even if they don't know what a "meme" is. In fact, "meme" is a meme. Just say "information" - it's what you mean anyway.

Genetic drift and the founder effect are actually the primary mechanisms of speciation. Given two very similar populations, natural selection will tend to act on them in the same way. Given enough time (and enough drift), natural selection will act very differently on the two populations, leading to speciation.

Well, you can spell potato, so you're obviously not a Republican. Just a joke as far as the fluid thing.

It would take quite a long time to actually form two separate species, depending on the definition. If you're looking for the inability of two groups of humans to produce fertile offspring, that would take millions of years. If you're looking for simple reproductive isolation, the Maoris and Navajos are essentially two separate species because they don't reproduce (geographic isolation). If the Maori and Navajo were the only two groups of humans on Earth, scientists would likely consider them separate species.

Energy is actually usually stored in the form of sugars and fats. ATP is the intermediary and there is a tightly regulated ratio of ATP/ADP at any given time in the cell.

A potato is not a fluid.

You can culture bacteria on a slice of potato, too. A centrifuge is really only useful if you want to do stuff with mammals or you're going to be isolating nucleic acids/proteins (neither of which are really hobbyist things).

Ahahaha! Oh, how much you will make! I'm a lab tech right now with a B.S. making 30K a year (in Manhattan!), and that's the most money I'm going to make for at least 6 years.

It's going to happen unless global warming or nuclear weapons destroy us first. 6 billion human beings (that are constantly traveling) on a planet this size are just too fertile a playground for pathogens. It doesn't have to be avian flu. Our grandchildren are going to live in a very different world from the one of today.

Um.. Not ever elect a Bush to office again? The research strategies require NIH money, the vaccine production requires somebody who's not in the pockets of the pharmaceutical industry to tell them what to do, and the Chinese/Vietnamese need to change their poultry production patterns.

Molecular cell bio blah blah blah - just like everybody else. Angiogenesis in lymph nodes right now, but that's not a permanent thing. BTW, radiation sucks. I am so glad that the job that I'm working in right now does not require me to work with radiation any longer.

snRNAs serve as recognition molecules for intron splice sites. As far as telomere maintenance, I assume they also serve as recognition molecules to be sure that the repeats are long enough.

The Soviets, before their country collapsed, were trying to engineer flu virus with conotoxin (the deadliest toxin in the world). This would be a very stupid idea. This would make 1918 look like a walk in the park. But, hey, the US had multi-megaton weapons pointed at radio towers in the USSR, so we're not exempt from this type of stupidity either.

Dendritic cells can kill T cells, in order to protect the T cells from attacking the body. T cells can kill dendritic cells, but really only if the dendritic cells are infected or the person has an autoimmune problem like lupus. I think that the dendritic cells induce apoptosis in the T cells, so they probably act through the Fas pathway. Here's a paper about dendritic cells and T cell tolerogenesis: Gad M, Claesson MH, Pedersen AE. Dendritic cells in peripheral tolerance and immunity. APMIS 2003;111:766–75. And yes, when DCs are infected, they present their cytosolic antigens by MHCI.

Actually, I wasn't entirely truthful about the MHCII expression on dendritic cells before. Naive (unactivated) dendritic cells express MHCII to a very low extent. In this state, when the dendritic MHCII presents antigen to a T cell, and the T cell recognizes it, the dendritic cell figures that the T cell is recognizing "self" antigen - that is, the T cell wants to kill your own cells. So the dendritic cell signals that T cell to kill itself. However, when the dendritic cell gets a signal that an infection is ongoing (ie, DNA containing CpG repeats = viral infection; lipopolysaccharide = bacterial infection), it starts expressing a lot of MHCII and endocytosing a lot of foreign antigen to present. These "activated" dendritic cells don't kill the T cells, they activate them. And the activated T cells activate B cells in turn. So, by the most circuitous route possible, to answer your question, MHCIIs only present endocytosed antigen. However, many viruses (and bacteria?) have evolved to take advantage of the endocytosis route. Influenza virus, for one, signals the cell to endocytose the virus particle. When the endocytosed vacuole (containing the virus) becomes acidified in the process of forming a lysosome, the pH change causes a protein in the flu virus's envelope to change shape and fuse the virus envelope with the lysosome envelope, thus releasing the viral genome into the cytosol. I don't know offhand if any viruses have specifically taken advantage of the dendritic/macrophage endocytosis process, but I'm sure some have. So the answer to your question would be yes to both, but in most situations, the dendritic cell is presenting antigen without actually being infected. Sorry to go on so long, but this is what I do at my job. I actually just injected a bunch of mice today with artificially activated dendritic cells.

I have about as much respect for the bible thumpers' position that abortion is murder as a do for the ultra-hardcore vegans who think that roach motels are murder. Actually, I have less respect for the bible thumpers because, at the very least until the beginning of the third trimester, a roach is more conscious than a fetus. My definition of human life only respects consciousness. And I can hear the objection now: but what about severely retarded people? And my response is that, unless they are conscious, they're not human. They might be happy and want to be alive, but cows are happy and want to be alive and we slaughter millions of cows every year for no really valid reason except we like how they taste.

I'm pretty sure that all cells express MHCI; for dendritic cells (and probably macrophages), the MHCII expression level is a function of the activation state of the cell. So not all dendritic cells express MHCII.