Campylobacter bacteria, the leading cause of food-borne illness in the United States, penetrates into cells like?

According to a report at the annual meeting of the American Society of Cell Biology held in San Diego last December, Yale University researchers have now explained some questions about the original. The leading cause of foodborne illness in the US - a bacterium - can penetrate intestinal cells without being detected and destroyed.

When scientists were only in the initial stage of basic explanation for how the bacteria Campylobacter jejuni (campylobacter) caused infection, Robert Watson, a graduate student in the Department of Microbiology of Microbiology of the Faculty of Medicine, University Yale has been studying this bacterium in a better way and says it follows a strange pathway to cause cell infection.

Because cells stack in the gut where campylobacter infects bacteria that normally do not attract bacteria or any other element as large as bacteria, Watson and his instructor are professors of Microbiology and Biology. cell Jorge Galán of Lucille P Markey organization, conducted a study on the pathway of infection through cells.

They found that campylobacter infects the intracellular pathway, the path used by cells to reconstruct molecules from their surface. Later, it quickly redirects and creates a separate intracellular network of vacuoles filled with campylobacter bacteria, also known as cell sacs, that will eventually advance to the nucleus, and eventually focal near the Golgi set - the cell transport center.

Fluorescent dye shows Campylobacter jejuni (red) inside a cell, and tubular microstructures of the cell (green) network after 6 hours of infection (Photo: Watson / Yale )

"For more than two decades, it has been known that campylobacter can penetrate the epithelial cells of the intestine, but until now no one has demonstrated how this bacterium has penetrated," said Watson. and where to stay. This implies that this bacterium has created a special mechanism for cell entry. It seems that Campylobacter has found a special way to approach cells and form a cell of its own.

According to estimates by the US Centers for Disease Control and Prevention, every year 2.4 million Americans suffer from 'Campylobacter infections' , one of the most common causes of diarrhea in the world. Most patients recover after a few days of discomfort, but it can be life threatening for people with compromised immune systems, including those with AIDS. In addition, a serious but rare complication of campylobacter infection is the onset of an autoimmune disorder - also known as Guillain-Barré paralysis syndrome.

"Chicken is often the source of campylobacter bacteria," said Watson . Although people already know that salmonella is an infectious bacterium, according to Consumer Reports, the January 2007 issue, the increase in campylobacter is a notable problem. Analysis results of fresh chicken samples sold nationwide show that up to 80% of tested chicken contains campylobacter bacteria. '

Normally, substances that penetrate into cells move to chambers known as cytoplasmic cells, where they are broken down by an acidic enzyme mixture. By observing the points of this intrusion process, Mr. Watson and Mr. Galán can monitor when bacteria infect a host cell, bind to the protein that points to the original EEA-1, and then is a Lamp-1 late-protein protein.

"Although point proteins show that sneaky campylobacter bacteria invade the normal secretory cells, the information obtained from the dyes that help find traces does not show that," said Watson . Although dyes cross the intracellular and localized pathways along with other substances in the gastrointestinal bodies, it is surprising that the dye does not penetrate the vacuoles containing campylobacter, ie the bacteria did not Take the usual route.

Mr. Watson and Galán also examined the role of Rab GTPases, two proteins involved in the maturation of regenerative chambers. These tests and other trials provide further evidence that campylobacter does not follow the normal intracellular pathway at the beginning and that vacuoles containing campylobacter are removed to near the nucleus. , where they are closely linked to the Golgi set.

"Finding out the path of this bacterium gives us a new perspective in understanding infection and finding a way to combat it," Galán said . In the next step to learn about campylobacter, Mr. Watson and Mr. Galán will continue and expand their research, including studies of infected mice and carrying this type of bacteria but not shows symptoms of acute infection.

The Ellison Medical Foundation funded this study.

Hong Linh