Rare tick blood disease
Spirochetes Unwoundby Microbe Fan. With kind permission of the author.
by Microbe Fan
The deer tick, Ixodes scapularis. Photo: Scott Bauer, USDA Agricultural Research Service, Bugwood.org. Source.
In the northeastern United States the Lyme disease spirochete Borrelia burgdorferi spreads from one white-footed mouse to another by hitching a ride in the deer tick Ixodes scapularis. Transmission between tick and mouse occurs during the tick's rare blood meals. The larval tick acquires B. burgdorferi from an infected mouse during a blood meal late in the summer, and the spirochetes take up shelter in the tick's midgut. Later the larva molts into a nymph, which then completes the transmission cycle by feeding on an uninfected mouse during the next spring or early summer.
Although blood is potentially a rich source of nutrients for both tick and spirochete, the cells lining the tick's gut rapidly engulf the nutrients, including glucose, an energy-rich sugar favored by B. burgdorferi. The spirochetes must therefore rely on other energy sources if they are to survive the many months between tick feedings. How does B. burgdorferi fuel its survival during this period?
A study in the July issue of PLoS Pathogens has shown that B. burgdorferi metabolizes the tick's antifreeze while living in its midgut. Many arthropods and insects produce large amounts of antifreeze to protect themselves from freezing temperatures. The Ixodes tick's antifreeze is glycerol, the same stuff that's often added to enzymes to keep them from freezing in laboratory freezers. The amount of glycerol found in other organisms is too low to serve as antifreeze. I describe below how B. burgdorferi handles glycerol, but the same enzymes are found in most organisms that metabolize glycerol, including humans.
Modified from Figure 1 of Pappas et al., 2011. The BB numbers are the gene ID numbers assigned when the B. burgdorferi genome was sequenced. The individual steps of glycolysis are not shown. Source.
The B. burgdorferi genome encodes homologs of a glycerol transporter (GlpF), glycerol kinase (GlpK), and glycerol-3-phosphate dehydrogenase (GlpD), which are used by the bacteria to take up and metabolize glycerol (see figure). The figure also shows that B. burgdorferi can break down glucose by the glycolytic pathway (glycolysis) to supply its carbon and energy needs.
You might also like
Antrodia Cinnamomea Liquid Pure Extract - 25 g/L of polysaccharides per serving - SGS Certified, cGMP Certified, Guaranteed Authentic, 99.6% rDNA Proven Genuine - 30 bottles, 20ml per bottle - Made in Taiwan.
Health and Beauty (CGB Corp.)
Dragsbaek: 5 public health threats scarier than Ebola — Longview News-Journal
Children died not from a rare infectious disease but from a vaccine-preventable disease that we didn't protect them from. 2. Pertussis: In 2013, Texas reported 3,985 cases of pertussis, or whooping cough — more than any other state in the U.S.