Ticks: scary in its efficiency
Chain saws, hockey masks and the undead are all classic symbols of horror. But for a true shiver of dread, take a look at a tick.
When seen with an electron microscope, a tick's mouth has what look like twin saws (chelicerae) flanking an appendage (a hypostome) that appears to be a barbed sword.
The video is even scarier — particularly as the creature's ability to bore down and settle in may afflict anyone who spends time outdoors. Such a video, published with a research paper in the Proceedings of the Royal Society B, was made to help scientists understand how the tiny ticks that carry Lyme disease bacteria cut into the skin and then manage to hang on for days.
The immature tick, or nymph, in the video is about the size of a poppy seed. An adult is more like a sesame seed. The tick wanders, picks its spot and goes to work. As it cuts, it looks like it is doing the breast stroke with its pair of mouth saws. That movement cuts and pulls back the skin, plunging the hypostome deeper with each stroke, barb by barb, which makes them difficult to extract.
The tick's ratchet system, a marvel of efficiency, can do extensive damage: About 30,000 cases of Lyme disease are reported in the United States each year, with concentrations in the Northeast and Upper Midwest, said the Centers for Disease Control and Prevention.
new genes tied to alzheimer's
In the largest genetic analysis conducted on Alzheimer's, an international group of researchers has identified 11 new genes associated with the disorder, doubling the number of known gene variants linked to it.
The International Genomic Alzheimer's Project, a collaboration of two groups in the United States and two in Europe, scanned the DNA of 74,076 older volunteers from 15 countries — including people with and without the disease — to look for gene variants involved in late-onset Alzheimer's, the most common form.
The study in Nature Genetics provides additional evidence of the involvement of certain genes in Alzheimer's, such as one connected to the abnormal accumulation of amyloid protein in the brain. It also finds new gene-related risk factors that may influence cell functions.