Sunday, April 15, 2012

OBJECT #7: Hercules Beetle

This isn’t a real Hercules beetle, but it’s almost as big as a real one.  It measures almost a foot (30 cm) in length.  It’s a model that my younger daughter made for a contest that the Penn State Entomology Department sponsors every fall.  They hold a huge Insect Fair and one event is the Build-A-Bug contest.  One year our homeschool group incorporated this contest into our insect unit and helped each student build a bug.  My daughter chose the Hercules beetle (maybe partly because she knew how fond I am of beetles).  The basic shape was made from cardboard and wire then covered with paper mache.  Then a heavy coat of paint and shiny coat of varnish.

    The most poignant lesson my daughter learned at the bug festival that year wasn’t about insects, but about people. The contest turned out to be juried by the all the spectators who came through the bug contest room, so the more family and friends a contestant had, the better their chance of winning.   Sure, there were some entries that were so good that they got votes no matter what, but overall, the contest was quite a bit skewed toward those who had brought along a huge fan club.  We were just us, total of three votes.  I looked a my daughter, shrugged, and said, “Oh well, life’s just like that sometimes.  You did a really nice job on your project and I’m proud of your work.  I’m going to hang it on the wall in my studio.”  So I did  and it’s been there  for... hmm... can it be seven years already?  Wow.

    Speaking of beetles, our house has been invaded by the one of the newest arrivals to North America-- a beetle that falls into the genre of “stink bug” or “squash bug.” (Entomologists call these particular invaders “brown marmorated stink bugs.”)  I think technically it may be a “shield bug,” which is actually a “true bug.”   (Beetles aren’t really “bugs.”  Only certain kinds of bugs are technically “bugs.”  Beetles are coleoptera and "bugs" are hemiptera.)

    Anyway, about once or twice a month, we find one of these little critters crawling up a curtain or buzzing about a light.  They are easy to catch and very harmless (unless you are a plant) so we just pick them up and put them outside.  We’ve found them in the house all the way through the winter months, so we know they are not just crawling in through a crack somewhere.  They must have wintered over in the house.  But we can’t discover where they are hiding out.  We’ve looked everywhere that seems likely for a bug to hide out.  But they just appear seemingly out of nowhere.

    My son read a research article online that gave us some info on these bugs, It seems these bugs are new arrivals from Asia.  They appeared in North America only about a decade ago and probably have spread from the east coast.  They have crept their way west and now, as I can witness, are colonizing central Pennsylvania.  They eat most plants, including those found in gardens and commercial farms.  Entomologists at various universities are studying them to find out if there is a safe way to get rid of them but as of yet have not come up with anything.

    We didn’t take the “stink” part of the name too seriously until on evening my daughter called me into her room to try to track down a strange smell.  It didn’t fit into any of our usual categories of smells.  We knew it was not a dead mouse or stinking cat litter or spilled paint.  Hours later my daughter suddenly remembered that she had found one of those bugs, crushed it with a tissue, and put it into her trash can. 

    My son also read in that article a scary story about a house that was infested with hundreds of these bugs, and as fast as the owners killed them, they were replaced by new ones.  The sorcerer’s little apprentices. (They did finally reduce the population down to a manageable level somehow.) 

    Well, at least I’m not phobic about bugs, and the good news is that they don’t bite or sting.

Monday, April 2, 2012

OBJECT #6: T2 virus

    If you’ve never read about bacteriophages, I doubt you would ever be able to guess what this thing is.  This is a paper model of a virus.  When you think of viruses, usually what comes to mind is sneezing and coughing.  It’s easy to forget that viruses don’t just affect humans.  There are many types viruses, each one specialized to attack one particular part of one particular type of living cell.  The first virus ever discovered was in plants.  There are also viruses that attack bacteria.  These types of viruses are called bacteriophages (“phage” means “eat” in Greek).  This type of bacteriophages is known as the T2.  There are also T4s and T6s.  The T2 is my favorite “phage” and is the one most common one drawn by artists who are illustrating articles on these things.  The reason for this is pretty obvious-- they look bizarre.  Usually people say they look like a lunar landing module.

    This model is just made from paper (heavy card stock paper) and a few chenille stems.  (It’s one of my free downloads, so you can make one, too!)  I sprayed the top lightly with silver spray paint to try to make it look less like paper.   In a real T2, the top part is made of protein and has a piece of DNA inside it.  The legs are not called legs, but rather “tail fibers.”  The ends of these fibers are what grabs onto the outside of the bacteria cell.  After it latches on, the neck sort of retracts, pulling the head down and propelling the DNA into the cell.  Once in the cell, the DNA takes over the cell machinery and turns the poor bacteria into a T2-producing factory.  When the bacteria gets full of T2s, it bursts open and all those new T2s go out looking for more bacteria cells to infect.

    Sounds gruesome (and even more so when you think that the same process happens to our cells when we catch a virus) but we could use these phages to our advantage to fight unwanted bacteria in our bodies.  The phage cannot possibly attack your cells.  The tail fibers will only stick to certain bacteria.  They won’t stick to your cells.  So... why are we not using these things to fight infections?  Some countries are-- such as Georgia (the country in Asia, not the US state).  They’ve got quite a research program going on these things.  They’ve found that these viruses are able to keep up with the survival mutations of the bacteria.  Antibiotic resistance is a big problem when dealing with bacteria.  But the T2 can manage to counter these mutations with mutations of their own, constantly keeping their mode of attack up to date.  Whenever the research hospital in Georgia finds an antibiotic resistant bacteria, all they need to do is take a microbial culture from the hospital’s sewer pipes and they’ll find phages that have already learned how to attack this new resistant strain.  So why aren’t other countries pursuing this research?  My guesses are that most people would say “No” to any treatment that involved a virus, and, more importantly, I don’t think you can get a patent on them, which rules them out as a cash cow for pharmaceutical companies.  But it’s nice to know that there is a Plan B out there, when all the drugs stop working.

    A number of years ago, I made a very large T2 for a science fair I did with my homeschool group.  I don’t know why I do things like this.  One day I just got it into my head that I needed a huge T2 virus.  I can’t brag that the construction was anything to “write home” about.  The top was just cardboard covered with sequined fabric.  The legs (oops--tail fibers) were hard to assemble because of the angles in involved.  I used metal angles that I adjust to less than 90 degrees.  The legs could be unscrewed for storage, and poor T2 spent many months in storage, only coming out for special events now and then.  The last time I got it out I discovered that it had become very wobbly, and making the determination that rebuilding was easier that repair, I decided to retire the T2 from my collection of junk in the garage.  (But I have not made a replacement yet.  Space is getting tight in the garage.)  I decided a better replacement was a hands-on activity about phages, where kids could assemble and disassemble T2s.  I made dozens of little cardboard heads, plastic DNAs, wooden necks and chenille stem legs.  When the kids finish assembling the T2s, they go around to the other side and take them apart.  Kids think taking them apart is just as fun as putting them together, because there are little slots to stick all the parts into.  Kids love sticking things into holes and slots.  This exhibit is part of my traveling summer science museum.