Infectious diarrhea, a common disease
of children, is responsible for over 2 million infant deaths annually in
developing counties alone. A primary cause of this and other devastating
conditions is enteropathogenic bacteria, which attack the intestinal tract when
contaminated food is consumed.
The infection process involves
hundreds of genes and proteins, both in the infectious bacteria and the human
host. However, the processes by which the pathogens establish themselves in our
gut are poorly understood.
Now, a new study published in the
journal Science, by researchers at the Hebrew University of Jerusalem's Faculty
of Medicine, describes how pathogens sense their host,
and tailor their gene expression to exploit their host to cause disease. The
research was led by led by Prof. Ilan Rosenshine, the Etta Rosensohn Professor
of Bacteriology at the Hebrew University.
Working with a pathogenic strain of E.
coli, the researchers found that the bacteria can sense attachment to the human
intestinal cells and activate gene expression in response. This was
demonstrated by engineering one of these genes to express a protein that stains
the expressing bacteria to appear green under the microscope. Under microscopic
examination, the researchers observed that only the attached bacteria fluoresce
in bright green, whereas non-attached bacteria remain dark.
The researchers also deciphered how
upon sensing that it has attached to intestinal cells, the pathogen reorganizes
its gene expression, including genes involved in virulence and metabolism, to
exploit the host cell. These findings may lead to the development of new
strategies to combat bacterial infection.
See:
Posted by Dr. Tim Sandle
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