Friday, 25 August 2017

More Malevolence From the Nasty Designer?

Leprosy turns the immune system against itself, study finds | University of Cambridge

It must be difficult being a dedicated creationist. You need to believe so many diametrically opposed views simultaneously.

This paper presents an almost perfect example because a dedicated creationist must hold at least two such views simultaneously. They need to hold to the view that this bacterium was intelligently designed to circumvent the human immune system (that the same designer had designed to protect us and then had apparently regarded that as a problem to be solved!) and to the view that something capable of this degree of mendacious malevolence is an omni-benevolent, maximally good god.

An international team led by researchers at the University of Cambridge, UK, and the University of Washington, the University of California Los Angeles and Harvard University, USA, have shown how Mycobacterium leprae that cause leprosy has turned our immune system against us. It was already known that leprosy causes nerve damage by stripping away the myelin sheath that surrounds and protects nerve fibres, but it was not clear exactly how this was done.

Highlights
  • Mycobacterium leprae infection of zebrafish damages nerves, causing demyelination
  • Nerve damage requires M. leprae phenolic glycolipid (PGL-1) and host macrophages
  • PGL-1 induces macrophages to produce excess nitric oxide
  • Excess nitric oxide damages nerves by damaging their mitochondria

Summary
Mycobacterium leprae causes leprosy and is unique among mycobacterial diseases in producing peripheral neuropathy. This debilitating morbidity is attributed to axon demyelination resulting from direct interaction of the M. leprae-specific phenolic glycolipid 1 (PGL-1) with myelinating glia and their subsequent infection. Here, we use transparent zebrafish larvae to visualize the earliest events of M. leprae-induced nerve damage. We find that demyelination and axonal damage are not directly initiated by M. leprae but by infected macrophages that patrol axons; demyelination occurs in areas of intimate contact. PGL-1 confers this neurotoxic response on macrophages: macrophages infected with M. marinum-expressing PGL-1 also damage axons. PGL-1 induces nitric oxide synthase in infected macrophages, and the resultant increase in reactive nitrogen species damages axons by injuring their mitochondria and inducing demyelination. Our findings implicate the response of innate macrophages to M. leprae PGL-1 in initiating nerve damage in leprosy.


By using zebrafish in which the myelin was made florescent, the scientists could observe the process more clearly. What they found was that M. leprae settles on the surface of the myelin sheath where it is eaten by phagositic macrophage cells. These cells are part of the body's defences and normally 'eat' and destroy bacteria that get into the body. As with tuberculosis which is closely related to leprosy however, the M. leprae bacilli are not destroyed but continue to live in the macrophages. This slows down the macrophages which should be moving up and down the myelin sheath, repairing any damage. Instead they settle on the surface of the myelin, form doughnut-shaped bubbles, and start to destroy it. By knocking out the macrophages, the scientist showed that the freed M. leprea don't do any damage themselves.

Investigating further, the team further demonstrated how this damage occurs. A molecule known as PGL-1 that sits on the surface of M. leprae ‘reprograms’ the macrophage, causing it to overproduce a potentially destructive form of the chemical nitric oxide that damages mitochondria, the ‘batteries’ that power nerves.

What M. leprea does is essentially to turn the repair mechanism into a destruct mechanism. A really neat little trick - if you are feeling particularly nasty and vindictive and enjoy causing suffering and misery.

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2 comments :

  1. Rosa, dear lady, well I am truly depressed. The state of Florida's Governer just signed a bill that directed both Creationism and Evolution be taught and that any materials used for the classes, anyone couls obnject to it, perhaps even disallow it if it disagrees with a holy book. This is in line with these idiots' wedge document, the idea being to do whatever it takes to get their Sunday school fairytales into a science class and to then protect it from being removed, even by the courts, as Judge Roberts did in the Dover issue. Even library books the law allows for challenges, or for removal. Frankly, I hope I was dreaming of a worst case that could occur in this country, to do with these knuckle draggers. BUT since an insane RW was approved for the SCOTUS by name of Gorsuch now to replace Scalia crazy, I fear it isn't a bad dream. But then there is the 1st Amendment that states a freedom of religion. If it stands then with a super majority GOP of all 3 legislatures, Gov, and both legislatures, we are then doomed as each state copies this asshole Gov Scott's move essentially we are then GODDAMNED by the least of us, by these religious idiots. Can I please find a new country to move to? Peace, Rosa.

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    Replies
    1. As the US Law stands I would have thought that was a clear breach of the Establishment Clause. Are the ACLU and FFRF doing anything about it? What would happen is there is disagreement between the Bible and the Qur'an or the Hindu Vedas or, say, a Wiccan creation myth? Would they all get taught or can any of those demand the other myth not be taught?

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