Cutest Protist: Love Actually..or Splitsville?
If you go down in the woods today, you’re sure of a big surprise. No, not the Teddy Bear’s picnic. Giardiasis is a common and explosive form of diarrhea caused from drinking contaminated water from mountain streams and “clean water” sources, often during camping. Also known as Beaver Fever, wild animals and pets can get the runs too. Giardia lamblia is wonderfully weird:
• First described in 1681 by Antony van Leeuwenhoek who examined his own diarrhea under a microscope and wrote, “I have sometimes also seen animalcules a-moving very prettily; some of ‘em a bit bigger, others a bit less, than a blood globule… furnisht with sundry little paws, where with they made such a stir”.
• Despite the heart-shape in the left image, Giardia lacks a love life and reproduces only asexually, splitting inside the cyst into two cells (trophozoites) that are released within the intestine.
• There are two identical and functional nuclei, which makes the stained Giardia look like it has two eyes (right image). Other organisms that have multiple sets of chromosomes house them in the same nucleus. The “smile” comes from the median body which organizes the cell’s skeleton (microtubules).
• Considered the most primitive of eukaryotes, Giardia was believed to have no mitochondria. But now it appears to have some remnants of them, called mitoplasts. Being anaerobic, they don’t respire or make ATP in their mitochondria. Other eukaryotes, even anaerobic ones, have mitochondria.
IMAGES: Digitally colored scanning electron micrograph of Giardia cells in late stage of cell division, courtesy of CDC/ Dr. Edwin P. Ewing, Jr. (left). Stained Giardia looks like a smiley face with two nuclei eyes (right). More cute images: http://www.tumblr.com/tagged/giardia