The Dawn
Mitochondria are the cell's power producers. They convert energy into forms that are usable by the cell. They are the sites of cellular respiration which ultimately generates fuel for the cell's activities. The number of mitochondria in a cell can range from a few to several thousand, depending on the type of cell.
Mitochondria are tubular or oblong shaped and are bounded by double membranes. The double membranes divide the mitochondrion into two distinct parts: the intermembrane space and the mitochondrial matrix. Mitochondria are semiautonomous in that they can divide and grow to make more of themselves. They also have their own DNA and ribosomes. To learn more about mitochondria and other cellular components, visit Journey into the Cell.
Strep Bacteria and the Immune System
Saturday August 16, 2008
Researchers have discovered how Strep bacteria are able to survive and spread throughout the body. The bacteria produce a substance, SpyCEP, that inhibits the ability of immune system cells to respond to an infection. SpyCEP (Strep. pyogenes cell envelope protease) interferes with the production of a certain molecule in the body that sends signals to white blood cells when there is an infection. As a result, the bacteria go undetected until it is too late and the infection spreads.
In the study, the researchers isolated the Strep bacteria and removed the gene responsible for producing SpyCEP. They discovered that without the ability to produce SpyCEP, white blood cells were able to detect and destroy the bacteria. The study was conducted with group A Streptococcus bacteria. This pathogen strain is responsible for several types of diseases including strep throat and "flesh-eating disease."
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