PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Salmonella uses protective switch during infection

Possibly energy-conserving, switch suggests metabolic changes that researchers might exploit to fight systemic illness

2013-05-28
(Press-News.org) RICHLAND, Wash. -- For the first time, researchers have found a particular kind of molecular switch in the food poisoning bacteria Salmonella Typhimurium under infection-like conditions. This switch, using a process called S-thiolation, appears to be used by the bacteria to respond to changes in the environment during infection and might protect it from harm, researchers report this week online in the Proceedings of the National Academy of Sciences Early Edition.

S-thiolation protects proteins from irreversible chemical changes when a cell is stressed. The newly discovered switch might regulate when or how proteins work while offering protection, providing researchers insight into Salmonella infection.

"We continue to recognize just how clever this bug is in adapting to its environment," said systems biologist Josh Adkins of the Department of Energy's Pacific Northwest National Laboratory. "During infection it lives in hostile environments, and so it can use multiple approaches to adjust its functions."

Whole Ensemble

Salmonella Typhimurium causes food poisoning in people and can be fatal in the elderly or very young. Recent technological advances in the field known as proteomics are allowing researchers to explore how proteins, the workhorses of the cell, allow the bacteria to infect and cause illness. Most technologies that examine a cell's ensemble of proteins do so by chopping the proteins up. Adkins, lead author Charles Ansong and other colleagues wanted to look at whole proteins, which provides more information such as how proteins are regulated.

Cells regulate how proteins work in several ways. One of the most common adds molecular pieces that serve as gas pedals on proteins, turning them up or down in a grand orchestrated way. Proteomics methods that chop up proteins allow a researcher to determine that a particular protein was present, but not if it was actually functioning. Those methods also destroy evidence about how hard the gas pedal was pressed.

To identify which proteins were likely turned on or off during Salmonella infection, the team grew the bacteria either with rich food that satisfied all their nutritional needs or with nutrient-poor food that mimicked the kind of stressful environment the microbes find themselves in while infecting someone.

Then the researchers took samples of the bacteria and identified the proteins inside. They used a method called top-down proteomics, a technological advancement that allows researchers to look at wide swaths of whole proteins instead of just a few at a time. The team identified 563 unique proteins. This number is comparable to fungus and human studies but almost three times as many as in other bacterial studies using top-down proteomics.

They also determined if the proteins had molecular modifications on them. These can cap an end of a protein or dot the protein's length. Because different modifications can be mixed and matched on one protein, they ended up with a total of 1,665 different forms of the 563 unique proteins.

"This study shows how well top-down proteomics works, especially to get at regulatory information," said co-author Liljana Pasa-Tolic, who led top-down proteomics development with mass spectroscopist Si Wu at EMSL, DOE's Environmental Molecular Sciences Laboratory on the PNNL campus.

Gluts Versus Cysts

Of particular interest to the team were S-thiolation modifications. These modifications cover and protect a protein's sulfur atoms, which tend to snag each other like velcro and cause misshapen proteins. The modifications come in two flavors: a bulky glutathione and a compact cysteine. While glutathione modifications are pretty well studied, only four studies reveal cysteine modifications, and only two of those are in bacteria.

A total of 25 proteins sported glutathiones and another 18 wore cysteines. But nine of these stood out: The glutathiones and the cysteines attached to the same exact spot on the nine proteins. Not at the same time -- the team found that Salmonella used glutathiones at these sites when they were fat and happy, growing with rich food. When grown under stressful conditions with nutritionally poor food, the Salmonella swapped their glutathiones for cysteines.

In addition, switching S-thiolation modifications appeared to be a talent unique to Salmonella. The team checked other bacteria such as Escherichia coli, a common gut bacteria, and Yersinia pestis, which causes plague, to see if other species used this S-thiolation switch on their proteins. They didn't, suggesting that Salmonella had come up with this tactic during its own evolution.

The researchers speculate that Salmonella might use the smaller cysteine under stressed conditions as an energy saving device. Additional research will reveal what control functions the modifications are actually performing on the proteins.

### This work was supported by the National Institute of Allergy and Infectious Disease through interagency agreement Y1-AI-8494-01 and the National Institute for General Medical Sciences.

Reference: Charles Ansong, Si Wu, Da Meng, Xiaowen Liu, Heather Brewer, Brooke L. Deatherage Kaiser, Ernesto S. Nakayasu, John R. Cort, Pavel A. Pevzner, Richard D. Smith, Fred Heffron, Joshua N. Adkins and Ljiljana Paša-Tolić. Top-down proteomics reveals a unique protein S-thiolation switch in Salmonella Typhimurium in response to infection-like conditions, Proc Natl Acad Sci U S A, Early Edition online the week of May 27, 2013, DOI 10.1073/pnas.1221210110.

EMSL, the Environmental Molecular Sciences Laboratory, is a national scientific user facility sponsored by the Department of Energy's Office of Science. Located at Pacific Northwest National Laboratory in Richland, Wash., EMSL offers an open, collaborative environment for scientific discovery to researchers around the world. Its integrated computational and experimental resources enable researchers to realize important scientific insights and create new technologies. Follow EMSL on Facebook, LinkedIn and Twitter.

Interdisciplinary teams at Pacific Northwest National Laboratory address many of America's most pressing issues in energy, the environment and national security through advances in basic and applied science. PNNL employs 4,500 staff, has an annual budget of nearly $1 billion, and has been managed for the U.S. Department of Energy by Ohio-based Battelle since the laboratory's inception in 1965. For more, visit the PNNL's News Center, or follow PNNL on Facebook, LinkedIn and Twitter.


ELSE PRESS RELEASES FROM THIS DATE:

Study examines placement of tobacco and alcohol brands in movies rated for youth audiences

2013-05-28
An analysis of top box-office movies released in the United States indicated tobacco brand producer placements in movies have declined since implementation of the Master Settlement Agreement (MSA), but alcohol placements, which are subject only to industry self-regulation, have increased in movies rated acceptable for youth audiences, according to a study published Online First by JAMA Pediatrics, a JAMA Network publication. There is growing evidence that movies influence substance use behaviors during adolescence. Children's exposure to movie imagery of tobacco and alcohol ...

Snail shell coiling programmed by protein patterning

2013-05-28
Snail shells coil in response to an lopsided protein gradient across their shell mantles, finds research in BioMed Central's open access journal EvoDevo. In contrast the shell mantle of limpets, whose shells do not coil, have a symmetrical pattern of the protein Decapentaplegic (Dpp). There are many hundreds of different kinds of gastropods (slugs snail and limpets) - second only in number of species to insects. They have adapted to live on land as well as in fresh water and marine environments, and have altered their physiology to survive in different habitats and to ...

New safety test predicts reactions to novel drugs and cosmetics

2013-05-28
A simple lab-based skin test which eliminates the risk of adverse reactions to new drugs, cosmetics and household chemicals has been developed by a Newcastle University, UK team. It uses real human skin and immune cells to show any reaction such as a rash or blistering indicating a wider immune response within the body. The development is timely as it offers a reliable alternative for the cosmetic industry as a ban on the sale of any cosmetic product tested on animals came into effect across Europe in March. Professor Anne Dickinson from the Institute of Cellular ...

Pitt team finds mechanism that causes noise-induced tinnitus and drug that can prevent it

2013-05-28
PITTSBURGH, May 27, 2013 – An epilepsy drug shows promise in an animal model at preventing tinnitus from developing after exposure to loud noise, according to a new study by researchers at the University of Pittsburgh School of Medicine. The findings, reported this week in the early online version of the Proceedings of the National Academy of Sciences, reveal for the first time the reason the chronic and sometimes debilitating condition occurs. An estimated 5 to 15 percent of Americans hear whistling, clicking, roaring and other phantom sounds of tinnitus, which typically ...

Effective regulation of alcohol brand placements in movies could limit underage drinking

2013-05-28
(Lebanon, NH, 5/27/2013) —Researchers at the Norris Cotton Cancer Center have found that current constraints on advertising for alcohol products in movies that adolescents watch are not effective. The study, "Trends in Tobacco and Alcohol Brand Placements in Popular US movies, 1996 through 2009,"was published online in the May 27, 2013 JAMA Pediatrics. Studies have shown that movies influence smoking and drinking during adolescence: A 2012 Surgeon General's report noted a causal relationship between the initiation of smoking in adolescents and depictions of smoking ...

Surge in children accidentally eating marijuana-laced foods

2013-05-28
AURORA, Colo. (May 27, 2013) – A new study shows the relaxation of marijuana laws in Colorado has caused a significant spike in the number of young children treated for accidentally eating marijuana-laced cookies, candies, brownies and beverages. "We have seen an increase in unintentional ingestions of marijuana by children since the modification of drugs laws in Colorado," said George Wang, MD, lead author of the study and clinical instructor in pediatrics at Children's Hospital Colorado and the University of Colorado School of Medicine. "We need to educate marijuana ...

The formula for turning cement into metal

2013-05-28
LEMONT, ILL. --- In a move that would make the Alchemists of King Arthur's time green with envy, scientists have unraveled the formula for turning liquid cement into liquid metal. This makes cement a semi-conductor and opens up its use in the profitable consumer electronics marketplace for thin films, protective coatings, and computer chips. "This new material has lots of applications including as thin-film resistors used in liquid-crystal displays, basically the flat panel computer monitor that you are probably reading this from at the moment," said Chris Benmore, a ...

African Americans experience longer delays between diagnosis and treatment of prostate cancer

2013-05-28
Among men with prostate cancer, African Americans experience longer treatment delays after being diagnosed than Caucasians. That is the finding of an analysis published early online in CANCER, a peer-reviewed journal of the American Cancer Society. The study suggests that efforts are needed to reduce racial disparities in prostate cancer care in order to provide earlier treatment for African Americans. To see if there is a difference in the time from cancer diagnosis to initiation of treatment for African American men compared with Caucasian men with prostate cancer, ...

'Preferred retinal location' may aid rehabilitation in patients with central vision loss

2013-05-28
Philadelphia, Pa. (May 28, 2013) - Perceptual learning techniques may provide a useful new approach to rehabilitation in patients with central vision loss—taking advantage of visual plasticity that persists even in old age, according to a special article in the June issue of Optometry and Vision Science, official journal of the American Academy of Optometry. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health. The paper by Susana T.L. Chung, OD, PhD, FAAO, 2012 recipient of the prestigious Glenn A. Fry Lecture Award, presents new ...

New approach may allow faster spinal anesthesia for cancer patients at end of life

2013-05-28
San Francisco, CA. (May 28, 2013) – For patients with uncontrolled pain from terminal cancer, a new approach to calculating initial dosage may allow a quicker start of spinal analgesia—and less time in the hospital, according to a study in the June issue of Anesthesia & Analgesia, official journal of the International Anesthesia Research Society (IARS). Led by Dr Vivek Tim Malhotra of Memorial Sloan Kettering Cancer Center, New York, the researchers developed a set of equations for estimating the initial dose of intrathecal spinal pain relievers, thus avoiding the need ...

LAST 30 PRESS RELEASES:

New strategies to enhance chiral optical signals unveiled

Cambridge research uncovers powerful virtual reality treatment for speech anxiety

2025 Gut Microbiota for Health World Summit to spotlight groundbreaking research

International survey finds that support for climate interventions is tied to being hopeful and worried about climate change

Cambridge scientist launches free VR platform that eliminates the fear of public speaking

Open-Source AI matches top proprietary model in solving tough medical cases

Good fences make good neighbors (with carnivores)

NRG Oncology trial supports radiotherapy alone following radical hysterectomy should remain the standard of care for early-stage, intermediate-risk cervical cancer

Introducing our new cohort of AGA Future Leaders

Sharks are dying at alarming rates, mostly due to fishing. Retention bans may help

Engineering excellence: Engineers with ONR ties elected to renowned scientific academy

New CRISPR-based diagnostic test detects pathogens in blood without amplification

Immunotherapy may boost KRAS-targeted therapy in pancreatic cancer

Growing solar: Optimizing agrivoltaic systems for crops and clean energy

Scientists discover how to reactivate cancer’s molecular “kill switch”

YouTube influencers: gaming’s best friend or worst enemy?

uOttawa scientists use light to unlock secret of atoms

NJIT mathematician to help map Earth's last frontier with Navy grant

NASA atmospheric wave-studying mission releases data from first 3,000 orbits

‘Microlightning’ in water droplets may have sparked life on Earth

Smoke from wildland-urban interface fires more deadly than remote wildfires

What’s your body really worth? New AI model reveals your true biological age from 5 drops of blood

Protein accidentally lassos itself, helping explain unusual refolding behavior

With bird flu in raw milk, many in U.S. still do not know risks of consuming it

University of Minnesota research team awarded $3.8 million grant to develop cell therapy to combat Alzheimer’s disease

UConn uncovers new clue on what is leading to neurodegenerative diseases like Alzheimer’s and ALS

Resuscitation in out-of-hospital cardiac arrest – it’s how quickly it is done, rather than who does it

A closer look at biomolecular ‘silly putty’

Oxytocin system of breastfeeding affected in mothers with postnatal depression

Liquid metal-enabled synergetic cooling and charging: a leap forward for electric vehicles

[Press-News.org] Salmonella uses protective switch during infection
Possibly energy-conserving, switch suggests metabolic changes that researchers might exploit to fight systemic illness