Tufts researchers identify how Yersinia spreads within infected organs

Extension of technique improves the study of bacteria in organs

2013-09-16

(Press-News.org) BOSTON (September 16, 2013) — Researchers at Tufts University School of Medicine and the Sackler School of Graduate Biomedical Sciences at Tufts have identified how one type of bacteria, Yersinia, immobilizes the immune system in order to grow in the organs of mice. To do so, the researchers extended the use of a technique and suggest that it could be used to study other bacteria that use the same or similar means of infection. The study is published in the September 11 issue of Cell Host & Microbe.

Led by microbiologist Joan Mecsas, the research team studied a specific member of a family of effector proteins known as Yops. Like other effector proteins, Yops alter the immune system to make it possible for bacteria such as Yersinia to spread in infected organs and from organ to organ. The research team studied the Yop known as YopH in order to identify its specific effect within infected spleens.

Many bacteria inject proteins into cells in organs as a part of their infection process. The technique they used, called the TEM-1 reporter system, uses an enzyme and a dye to color-code cells. This enables researchers to see which of the many cells in an organ have been injected. The current study used the TEM system to identify injected cells but then, in an interesting first, gathered these cells from infected organs to study them further.

After isolating the color-coded cells from infected organs, the researchers determined how immune cells are made inactive by effector proteins, such as YopH and other Yops, by comparing cells with and without the specific effector protein. The research team used tissue samples from two sets of mice with Yersinia pseudotuberculosis: those with and without functional YopH proteins. They separated tissue cells from immune cells taken from spleens and compared suspended immune cells from the two sets of mice.

The researchers determined that YopH deactivates multiple proteins and blocks calcium flows vital to normal immune cell communication. Decreased immune cell communication allows Yersinia to continue spreading in infected organs without an effective response from the immune system.

"Being able to pull out and study cells from infected tissues that contain bacterial proteins enabled us to see the effects of YopH in tissues infected with Yersinia pseudotuberculosis. Our application of this technique may also work in bacteria similar to Yersinia, to understand how other bacteria cause damage in organ systems," said senior author Joan Mecsas, Ph.D., an associate professor of molecular biology and microbiology at Tufts University School of Medicine and member of the immunology and molecular microbiology programs at the Sackler School of Graduate Biomedical Sciences at Tufts.

"We know that two forms of food poisoning and some forms of pneumonias caused by E. coli, Salmonella, and Pseudomonas respectively, as well as other types of infections depend on the same system as Yersinia to infect humans and animals. There are also several bacteria that use related means to infect people and animals. This includes the bacteria that cause Legionnaires' disease, ulcers, cholera, various foodborne illnesses, pneumonias and even general infections such as some ear and sinus infections. This technique could be applied to understand these other bacteria," said co-first author Enrique Durand, Ph.D., a graduate of the molecular microbiology program at the Sackler School, now teaching biology in the International Baccalaureate (honors) program at Snowden International School at Copley in the Boston Public Schools system.

"Yersinia and bacteria with systems of infection like Yersinia can have drastic effects on organs, including inflammation that leads to appendicitis-like pain. Seeing the effect of the bacteria on specific cell types within organs, such as the spleen, has been challenging because cells grown in petri dishes cannot mimic the holistic environment of a mammalian system," said co-first author Hortensia Rolan, Ph.D., a postdoctoral scholar in the Mecsas lab.

Researchers have studied Yersinia since the discovery of the most well-known member of the Yersinia genus, Yersinia pestis, which causes bubonic plague (and which was found in squirrels in a national forest in Los Angeles County this summer). But Yersinia pseudotuberculosis, its near relative, is a standard Yersinia bacterium to study in labs.

Yersinia pseudotuberculosis, which is not related to tuberculosis, is a type of zoonotic bacteria, or one that can be transferred from an animal to a person. Infections in humans are rare and, like bubonic plague, it can be treated with antibiotics.

### Research reported in this publication was supported by the National Institute of Allergies and Infectious Diseases of the National Institutes of Health under award numbers T32AI007329, T32AI007422, and R01AI056068.

Rolan, H.G., Durand, E.A., Mecsas, J. (September 11, 2013). Identifying Yersinia YopH-targeted signal transduction pathways that impair neutrophil responses during in vivo murine infection. Cell Host & Microbe (14:3, pp. 306-317). DOI: 10.1016/j.chom.2013.08.013

About Tufts University School of Medicine and the Sackler School of Graduate Biomedical Sciences Tufts University School of Medicine and the Sackler School of Graduate Biomedical Sciences at Tufts University are international leaders in innovative medical education and advanced research. The School of Medicine and the Sackler School are renowned for excellence in education in general medicine, biomedical sciences, special combined degree programs in business, health management, public health, bioengineering and international relations, as well as basic and clinical research at the cellular and molecular level. Ranked among the top in the nation, the School of Medicine is affiliated with six major teaching hospitals and more than 30 health care facilities. Tufts University School of Medicine and the Sackler School undertake research that is consistently rated among the highest in the nation for its effect on the advancement of medical science.

If you are a member of the media interested in learning more about this topic, or speaking with a faculty member at Tufts University School of Medicine or another Tufts health sciences researcher, please contact Siobhan Gallagher at 617-636-6586.

ELSE PRESS RELEASES FROM THIS DATE:

Flame cultivation promising as weed control method for cranberry

2013-09-16

WAREHAM, MA--Cranberries are important agricultural commodities in states such as Massachusetts, Wisconsin, New Jersey, Washington, and Oregon. But cranberry-growing operations are challenged by weeds, which compete for precious resources and often decrease fruit yields and revenues. Producers currently rely on weed management strategies such as flooding and sanding cranberry beds, hand-weeding, or applications of pre- and postemergence herbicides. Recent interest in reducing chemical inputs into cranberry growing systems has led researchers to evaluate alternative methods ...

Low level blast explosions harm brain, says new study in Journal of Neurotrauma

2013-09-16

New Rochelle, NY, September 16, 2013—Repeated exposure to low level blasts (LLB) can cause symptoms similar to sports concussion. Soldiers or law enforcement officers called "breachers" receive training in using low level blasts for forced entry. They may be at risk for diminished neurocognitive performance and symptoms caused by the harmful effects of blast-related pressure changes on the brain, as described in a study published in Journal of Neurotrauma, a peer-reviewed publication from Mary Ann Liebert, Inc., publishers. The article is available free on the Journal of ...

Doing research in the pub

2013-09-16

This news release is available in German. Dim lighting, a jumble of conversations, and loud music: bar staff have to master numerous challenges when serving their customers. In a crowded place, they have to identify who would like to place an order and who does not. A Bielefeld research team analysed how the body language of the potential customer helps the bartenders to achieve this. The team found that real-life observations were at odds with the widespread belief that customers wave for signalling that they would like to order a drink. Analysing the real-life data ...

Study indicates space weather may be to blame for some satellite failures

2013-09-16

CAMBRIDGE, Mass-- Is your cable television on the fritz? One explanation, scientists suspect, may be the weather — the weather in space, that is. MIT researchers are investigating the effects of space weather — such as solar flares, geomagnetic storms and other forms of electromagnetic radiation — on geostationary satellites, which provide much of the world's access to cable television, Internet services and global communications. Geostationary satellites orbit at the same rate as the Earth's rotation, essentially remaining above the same location throughout their ...

2 NASA satellites track Typhoon Man-yi across Japan

2013-09-16

NASA's Aqua and Terra satellites captured images as Typhoon Man-yi made landfall in southern Japan and moved across the big island. Typhoon Man-yi was approaching Japan when NASA's Aqua satellite passed overhead and captured a visible image on Sept. 15 at 0410 UTC/12:10 a.m. EDT. Man-yi weakened to a tropical storm as it quickly crossed Japan dropping heavy rainfall and causing deadly mudslides when NASA's Terra satellite passed overhead on Sept. 16. Man-yi is now headed northeast into the Sea of Okhotsk. When Aqua passed overhead, a visible image was taken by the ...

Birth of Earth's continents

2013-09-16

VIDEO: This computer simulation spanning 2.5 billion years of Earth history is showing density difference of the mantle, compared to an oceanic reference, starting from a cooler initial state. Density is... Click here for more information. New research led by a University of Calgary geophysicist provides strong evidence against continent formation above a hot mantle plume, similar to an environment that presently exists beneath the Hawaiian Islands. The analysis, published ...

High debt load anticipated by majority of medical students; African-Americans most affected

2013-09-16

September 16, 2013 --The cost of a medical school education in the United States has been on the rise over the past 10 years. However, given racial and ethnic inequalities in access to financial resources, increases in the student debt burden may not be assumed equally. To evaluate the issue, researchers at Columbia University's Mailman School of Public Health analyzed data from a sample of over 2% of the U.S. medical students enrolled at 111 accredited American medical schools. In the sample of 2,355 medical students in 2010-2011, 62.1% of the medical students overall ...

Gut microbes closely linked to proper immune function, other health issues

2013-09-16

CORVALLIS, Ore. -- A new understanding of the essential role of gut microbes in the immune system may hold the key to dealing with some of the more significant health problems facing people in the world today, Oregon State University researchers say in a new analysis. Problems ranging from autoimmune disease to clinical depression and simple obesity may in fact be linked to immune dysfunction that begins with a "failure to communicate" in the human gut, the scientists say. Health care of the future may include personalized diagnosis of an individual's "microbiome" to ...

Non-traditional mathematics curriculum results in higher standardized test scores, MU study finds

2013-09-16

COLUMBIA, Mo. -- For many years, studies have shown that American students score significantly lower than students worldwide in mathematics achievement, ranking 25th among 34 countries. Now, researchers from the University of Missouri have found high school students in the United States achieve higher scores on a standardized mathematics test if they study from a curriculum known as integrated mathematics. James Tarr, a professor in the MU College of Education, and Doug Grouws, a professor emeritus from MU, studied more than 3,000 high school students around the country ...

New world map for overcoming climate change

2013-09-16

NEW YORK -- Using data from the world's ecosystems and predictions of how climate change will impact them, scientists from the Wildlife Conservation Society, the University of Queensland, and Stanford University have produced a roadmap that identifies the world's most vulnerable and least vulnerable areas in the Age of Climate Change. The authors say the vulnerability map will help governments, environmental agencies, and donors identify areas where to best invest in protected area establishment, restoration efforts, and other conservation activities so as to have the ...

LAST 30 PRESS RELEASES:

New biochar-powered microbial systems offer sustainable solution for toxic pollutants

Identifying the best high-biomass sorghum hybrids based on biomass yield potential and feedstock quality affected by nitrogen fertility management under various environments