Editors’ Picks from the May 2013 issue of mBio®

Bacteria Transmit Through Insect Yolk

Scientists have finally figured out how fruit flies pass on beneficial symbiotic bacteria to their young: Through the yolks of their eggs. Researchers from the Global Health Institute at Ecole Polytechnique Federale de Lausanne, show that Spiroplasma bacteria, an endosymbiont of Drosophila melanogaster co-opts the yolk transport and uptake machinery within the ovaries allowing efficient transmission of the bacteria from females to offspring.  Many insect species, including important disease vectors and crop pests harbor vertically transmitted endosymbiotics.  An estimated 5% to 10% of all insect species play host to Spiroplasma, which studies suggest confer resistance to macroparasites such as parasitoid wasps or nematodes.  The bacteria are largely unable to survive outside their hosts and until now little was known about the mechanism of transmission.  A better understanding of this mechanism is important because it might facilitate the creation of novel insect-endosymbiont combinations unable to transmit disease.


Fungal Pathogen Controlled by Light

Considerable effort has been taken to understand how the mold pathogen Aspergillis fumigatus senses its environment to facilitate growth within an immuncompromised host.  Now, researchers from Dartmouth College, Hanover, New Hampshire, demonstrate that this organism regulates a variety of processes in response to light. They show that the fungus responds to both blue and red portions of the visible spectrum.  The data also suggest that the photobiology of this fungus is complex and likely involves additional photosensory pathways beyond those the researchers studied in this paper.  Together the data demonstrate the importance of light on the physiology of A. fumigatus and provide a basis for future studies into this unexplored area of its biology.


Virus Gets into Bloodstream via Endothelial Cells

Reoviruses which invade the central nervous system appear to gain entry into the bloodstream by first infecting the cells that form the walls of the blood vessels according to researchers from Vanderbilt University and the Johns Hopkins School of Medicine.  Bloodstream spread of viruses within infected hosts is a critical but poorly understood step in viral disease.  Reoviruses first enter the host through the oral or respiratory route and eventually infect cells in the central nervous system via the bloodstream.  In this study the researchers found that the viruses made their way into the bloodstream by infecting the endothelial cells that form the walls of the blood vessels.  Understanding how reovirus is routed through endothelial cells may aid in the design of antiviral drugs that target this important step in systemic viral infections.



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The American Society for Microbiology is the largest single life science society, composed of over 39,000 scientists and health professionals. ASM's mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.