The Smell of Cat Pee

 
Most mammals have a keen sense of smell. That's why urinary odorants and pheromones are used to attract mates and mark territory. In most cases we can't detect these odors but there's one major exception.

The urine of cats contains chemicals that are easily detectable by humans. The smell is not pleasant. Mature cats will spay almost anything to stake out their territory, especially males). This isn't a problem if it's outdoors but it can be a major problem for indoor cats because carpets and spraying are not a good mix.

The urine of mature cats contains a chemical known as felinine (2-amino-7 -hydrozxy-5, 5-dimethyl-4-thiaheptanoic avid). Felinine excretion is stimulated by the hormone testosterone, which isn't produced until the cat reaches maturity. Both male and female cats excrete felinine in their urine but males typically excrete twice as much.

Felinine is odorless, to us. A recent paper (October 2006) describes how it is made and how it is converted to more pungent compounds.

The biochemical pathway leading to felinine begins with 3-methylbutanol- glutathionine (3-MBG) (compound A in the figure below). 3-MBG is a normal precursor in the synthesis of cholesterol but in cats some of it is converted to 3-methylbutanol-cysteinylglycine (3-MBCG) (compound B) by a pepdidase activity that removes glutamate. This reaction takes place in the bloodstream and 3-MBCG is excreted in the urine in cats of from the time they are born.

Mature cat urine contains high levels of protein, 90% of which is a medium-sized protein (70kDa) called cauxin. Cauxin levels rise as the cats reach maturity because transcription of the gene is stimulated by sex hormones. Cauxin is produced only in kidney cells and is secreted directly into the urine. The novel finding is that cauxin is a peptidase that cleaves 3-MBCG producing felinine (compound C). What this means is that production of felinine from 3-MBCG takes place in urine, probably in the nephrons before urine is released into the bladder.

Felinine breaks down into a number of smaller compounds that give rise to the characteristic smell of cat urine. The main breakdown product is 3-mercapto-3-methy-1-butanol formed by splitting felinine at the sulfur atom. Other breakdown products are formed. The complex mixture of derivatives is probably produced by a combination of unknown enzymatic act ivies and spontaneous reactions. The characteristic odor of domestic cats differs from that of lynx and bobcats and the differences are due to the concentrations of the various breakdown products of felinine.

Miyazaki, M., Yamashita, T., Suzuki, T., Saito, Y., Soeta, S., Taira, H., and Suzuki, A. (2006) A Major Urinary Protein of the Domestic Cat Regulates the Production of Felinine, a Putative Pheromone Precursor. Chemistry & Biology 10: 1071-1079.

Appeasers, Spaghetti Monsters, and NCSE

 
John West, one of the IDiots at the Discovery Institute, has posted an interesting article [Why Does National Center for Science Education (NCSE) Spokesman Think "Mocking Traditional Religion" is OK?].

West is referring to a newspaper article published in last Sunday's Toronto Star (see Church of the Flying Spaghetti Monster Makes Front Page of The Toronto Star). In that newspaper article, Glenn Branch of the National Center for Science Education (NCSE) defended the Church of the Flying Spaghetti Monster. West asks, why does NCSE think it's okay to mock religion in this case and yet go out of their way to defend religion in other cases?

We've heard for years from Branch's boss Eugenie Scott that evolution and religion are perfectly harmonious (indeed, the NCSE has helped use our tax dollars to promote the message that true theology endorses evolution, and its director Eugenie Scott has recommended that students study theological statements endorsing evolution during biology class). But now it turns out that mocking religion in the name of science is "probably healthy" and that it is illegitimate for proponents of ID even to question such anti-religious diatribes.

Good point. Does anyone know the answer? The people over at NCSE (and their allies like Ed Brayton) go apoplectic whenever some atheists criticize the silly superstitions of Ken Miller and Frances Collins. The Church of the Flying Spaghetti Monster mocks all superstitious beliefs, including those of theistic evolutionists. Why is one so bad but not the other?

As far as I'm concerned, it's just as much fun to mock theistic evolution directly as it is to do it through the Church of the Flying Spaghetti Monster.

Phases of the Moon

 
I've added the phases of the moon to the bottom of the left sidebar. This is in response to a request from somone who is really interested in astronomy and really interested in knowing whether my mood is affected by the phases of the moon. (It isn't, by the way. )

Some examples of the phases of the moon are shown below for viewing from Canada or Chile. Can you tell which is which? Do you know why they're different?

CURRENT MOON

lunar phases

CURRENT MOON

lunar phases

Compact Fluorescent Bulbs

 
Steve Reuland at Sunbeams from Cucumbers writes On the Wonders of Compact Fluorescent Bulbs. He makes a compelling case. I'm going to switch 10 light bulbs tonight.

Are Science Blogs Really About Science?

 
Greg Laden has posted a summary of the number of comments on articles put up on Pharyngula [Where's the beef(ing)?"]. As you might have guessed, there are way more comments on articles about creationism and religion than on articles about science.

This confirms my observation as well. I've also noted that straight reporting about, and praise for, the latest "breakthrough" seems to go down better than critical analysis and skepticism. In general, articles that challenge pre-conceived notions don't get as much attention as those that reinforce current dogma.

This raises the obvious question: are science blogs really about science?

Sometimes they are. Here's a list of the 50 best science posts as determined by an expert panel of judges [Science Blogging Anthology - The Council Has Spoken!]. Congratulations to the winners!

Why Are So Many Engineers and Physicians IDiots?

 
Stephen Meyer on Engineers and ID is an answer the the question of why are there so many engineers who believe in intelligent design, and why are there so few scientists. Meyer says it's because engineers are better able to recognize design. That's only part of the answer. The other, more important, part is that they don't know how to recognize good science because they're not scientists. They can't tell the difference between engineering and science.

The Cost of Mistakes address the observation that a higher percentage of doctors fall for ID compared to scientists. DaveScot explains that it's because doctors recognize the cost of mistakes. They know that an error will most likely have bad consequences so they see through the modern concept of evolution and recognize that errors can't lead to improvement. That's only part of the answer—and not a very important part. The real reason is that Doctors aren't scientists so they don't understand science even though they think they do because they passed biochemistry in medical school. That's why so many of them are IDiots.

Engineers and doctors play with science but they are not trained to be scientists. They are not biologists. They are not geneticists. They are not experts in evolution. It's about time we recognized that the vast majority of people who believe in intelligent design don't understand the first thing about science and how it's supposed to be done. That's why a higher proportion of non-scientists (doctors, lawyers, accountants, engineers, politicians) are IDiots.

If the Horse Is Dead, Why Keep Kicking It?

 
Bill Dembski notes the publication of two new book that demolish the arguments for intelligent design (Living with Darwin by Philip Kitcher and Darwin and Intelligent Design by Francisco Ayala). Dembski then asks If the horse is dead, why keep kicking it?.

I'm reminded of a quotation from a 1965 paper by Emil Zuckerkandl and Linus Pauling. They were publishing the first sequence based phylogenetic trees. When commenting on why we need more evidence for evolution they said ...

Some beating of dead horses may be ethical, where here and there they display unexpected twitches that look like life.

Zuckerkandl, E. and Pauling, L. (1965) in EVOLVING GENES AND PROTEINS, V. Bryson and H.J. Vogel eds. Academic Press, New York NY USA

Science Teaches Skepticism: That's a Good Thing

Monday's Molecule #8

 
Name this molecule. You must be specific. We need the exact chemical name and the common name. The chemical name isn't that hard but finding the common name and the function of the molecule is a lot more difficult. Comments will be blocked for 24 hours.

Comments are now open. Since I don't expect anyone to get the correct answer, I'll be posting the explanation in a separate article.

Most Important Medical Advance

 
Here's a poll that will make you think. The medical journal BMJ asks you to identify the single most important contribution to medicine since 1840 [Medical Milestones Poll].

It's a tough choice. I think I'll have to choose "sanitation."

[Hat Tip: Hsien Hsien Lei who wants you to vote for DNA.]

Opening Tomorrow

 
This is a picture of the Tim Horton's in my building on the university campus.

Timmy's has been closed for three weeks but it opens tomorrow when the students return. I can hardly wait (for Timmy's to open).

15 Questions for "Militant" Atheists

 
Oh, goody. A quiz. I love quizzes. This one comes from R.J. Eskow over at The Huffington Post [15 Questions Militant Atheists Should Ask Before Trying to "Destroy Religion"].

Here are my answers (yes, I know he didn't request answers, but what the heck; and, no, I'm not admitting to being a militant atheist, I just like quizzes) ....

1. somewhere in between
2. other forces
3. no
4. considerable
5. no
6. additional action
7. neither
8. no
9. both
10. not all and not just fundamentalists
11. yes
12. yes, no
13. both are needed
14. the latter
15. eradication of religion will improve mental health

[Hat Tip: PZ Myers, who only got 1 out of 15 correct]

Questionable Mission

 
Questionable Mission is the title of an editorial in the Washington Post. Here's an excerpt.

"THERE ARE over 25,000 Department of Defense leaders working in the rings and corridors of the Pentagon. Through Bible study, discipleship, prayer breakfasts, and outreach events, Christian Embassy is mustering these men and women into an intentional relationship with Jesus Christ," a narrator explains toward the start of a promotional video for Christian Embassy, an offshoot of Campus Crusade for Christ that focuses on diplomats, government leaders and military officers. As a uniformed Air Force Maj. Gen. Jack J. Catton Jr. explains, "I found a wonderful opportunity as a director on the joint staff, as I meet the people that come into my directorate, and I tell them right up front who Jack Catton is . . . and my first priority is my faith in God, then my family and then country. I share my faith because it describes who I am."

This is really scary. It's one of the reasons why we need to speak out against religion before it's too late.

[Hat Tip: Richard Dawkins]

Church of the Flying Spaghetti Monster Makes Front Page of The Toronto Star

 
Well, not exactly the "front"-front page. It's on the front page of the IDEAS section (Section B) of today's paper [In praise of an alternate creation theory: The Church of the Flying Spaghetti Monster gains infamy and faith.

Leslie Scrivener does a pretty good job of explaining what it's all about. The Church of the Flying Spaghetti Monster was set up to make fun of some of the arguments for the existence of God. If your argument for God also applies to the existence of the Flying Spaghetti Monster (as most do), then how good is it?

The Toronto Star even has the picture (above) of the famous Michelangelo painting that's on the ceiling of the Sistine Chapel.

I wonder what the appeasers have to say about the Flying Spaghetti Monster? I wonder if the agnostics are sincerely undecided about His existence?

Blogging

 
I'm still getting used to blogging. There are lots of tools available to help figure out what's going on. (Thanks to PZ, and others for helping me get established.)

One of the tools reveals where readers are located. This is pretty amazing. Each dot stands for someone who looked at my blog in the last few hours.