Yersinia pestis, the bacteria that causes the bubonic plague which in the year 541 (as the Black Death) and later in the Middle Ages decimated Europe. The effects of the plague are described in the nursery rhyme “We all fall down.”
Y. pestis mainly infects rats and other rodents which are the prime reservoir for the bacteria. Fleas are the prime vectors carrying the bacteria from one species to another. They bite rodents infected with Y. pestis, then they bite people and so transmit the disease to them.
Transmission of the plague to people can also occur from eating infected animals such as squirrels. Once someone has the plague, they can transmit it to another person via aerosol droplets.
Plague occurs in the U.S. It is treatable with antibiotics but, if not treated promptly, can promptly lead to death.
Yersinia is named after the Swiss bacteriologist Alexandre- Emile-Jean Yersin (1863-1943) who identified it in 1894 after a trip to Hong Kong looking for the agent that was killing thousands of people in southern China. The bacteria was also discovered at the same time by the Japanese bacteriologist Shibasaburo Kitasako.
YAC stands for yeast artificial chromosome, a vector (carrier) created and used in the laboratory to clone pieces of DNA. A YAC is constructed from the telomeric, centromeric, and replication origin sequences needed for replication in yeast cells. (The telomere is the end of the chromosome; the centromere is the chromosome region to which spindle […]
- YAG laser surgery
The use of a YAG (yttrium-aluminum-garnet) laser to do surgery. One use for a YAG laser in surgery is to punch a hole in the iris to relieve increased pressure within the eye from acute angle-closure glaucoma. In this type of glaucoma, there is a sudden (acute) increase in pressure in the anterior (front) chamber […]
A measurement of length that is equal to 0.9 meters, 3 feet, or 36 inches.
Involuntary opening of the mouth, accompanied by slowly breathing inward and then outward. Repeated yawning can be a sign of drowsiness, boredom, or depression. The yawn helps to open tiny air sacs (alveoli) in the lungs that can collapse during shallow breathing.
Involuntary opening of the mouth with respiration, breathing first inward, then outward. Yawning is often caused by the power of suggestion. Repeated yawning may be a sign of drowsiness. It can also sometimes be a sign of depression.