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Bacteria Use This "Toxin Gun"Against Our Cells


Bacteria Use This 'Toxin Gun' Against Our Cells

                         Debnath Ghosal, Grant Jensen (California Institute of Technology)

                                                                              Published in EMBO Reports - 2017


Scientists, by  a technique called electron cryotomography, have created a 3D image of a molecular structure that many different bacteria use to pump toxins into humans cells and spread antibiotic-resistance genes to other bacteria. Experts predict that by 2050, antibiotic-resistant bacteria will cause as many deaths as cancer.

Researchers looked specifically at Legionella. When Legionella invades a human cell, it wraps itself in a protective vesicle and opens the molecular structure, known as a type IV secretion system. The molecular "machine" sits in the cell membrane of the bacterium and proceeds to shoot tens of thousands of toxic molecules-hundreds of different types-into the human cell, hijacking cellular pathways and overwhelming the cell's defenses.. Some type IV secretion systems are thought to be instrumental in spreading antibiotic-resistance genes throughout the bacterial population. The structure of the type IV system is crucial to developing new antibiotics to disable it, A very similar machine is used by many bacteria-such as the pathogens that cause stomach cancer, Q fever, and whooping cough."
Most current antibiotics focus on destroying the cellular envelope that encompasses a bacterial cell, preventing it from replica breitling colt watches replicating, developing new antibiotics that target different aspects of the bacterial cell, such as the type IV secretion system, would enable us to block infections in additional ways.