How zinc starves lethal bacteria to stop infection

Contact: Dr Christopher McDevitt 61-449-823-946 University of Adelaide

Australian researchers have found that zinc can ‘starve’ one of the world’s most deadly bacteria by preventing its uptake of an essential metal.

The finding, by infectious disease researchers at the University of Adelaide and The University of Queensland, opens the way for further work to design antibacterial agents in the fight against Streptococcus pneumoniae.

Streptococcus pneumoniae is responsible for more than one million deaths a year, killing children, the elderly and other vulnerable people by causing pneumonia, meningitis, and other serious infectious diseases.

Published today in the journal Nature Chemical Biology, the researchers describe how zinc “jams shut” a protein transporter in the bacteria so that it cannot take up manganese, an essential metal that Streptococcus pneumoniae needs to be able to invade and cause disease in humans.

“It’s long been known that zinc plays an important role in the body’s ability to protect against bacterial infection, but this is the first time anyone has been able to show how zinc actually blocks an essential pathway causing the bacteria to starve,” says project leader Dr Christopher McDevitt, Research Fellow in the University of Adelaide’s Research Centre for Infectious Diseases.

“This work spans fields from chemistry and biochemistry to microbiology and immunology to see, at an atomic level of detail, how this transport protein is responsible for keeping the bacteria alive by scavenging one essential metal (manganese), but at the same time also makes the bacteria vulnerable to being killed by another metal (zinc),” says Professor Bostjan Kobe, Professor of Structural Biology at The University of Queensland.

The study reveals that the bacterial transporter (PsaBCA) uses a ‘spring-hammer’ mechanism to bind the metals. The difference in size between the two metals, manganese and zinc, causes the transporter to bind them in different ways. The smaller size of zinc means that when it binds to the transporter, the mechanism closes too tightly around the zinc, causing an essential spring in the protein to unwind too far, jamming it shut and blocking the transporter from being able to take up manganese.

“Without manganese, these bacteria can easily be cleared by the immune system,” says Dr McDevitt. “For the first time, we understand how these types of transporters function. With this new information we can start to design the next generation of antibacterial agents to target and block these essential transporters.”


The research has been funded by the Australian Research Council and the National Health and Medical Research Council.

Media Contact:

Dr Christopher McDevitt Research Fellow Research Centre for Infectious Diseases School of Molecular and Biomedical Science The University of Adelaide Mobile: +61 449 823 946

Professor Bostjan Kobe Professor of Structural Biology Australian Infectious Diseases Research Centre School of Chemistry & Molecular Biosciences The University of Queensland Phone : +61 7 3365 2132

Robyn Mills Media Officer The University of Adelaide Phone: +61 8 8313 6341 Mobile: +61 410 689 084 robyn.mills@

Obese stomachs tell us diets are doomed to fail

Public release date: 16-Sep-2013 [

Contact: Amanda Page 61-882-225-644 University of Adelaide

The way the stomach detects and tells our brains how full we are becomes damaged in obese people but does not return to normal once they lose weight, according to new research from the University of Adelaide.

Researchers believe this could be a key reason why most people who lose weight on a diet eventually put that weight back on.

In laboratory studies, University of Adelaide PhD student Stephen Kentish investigated the impact of a high-fat diet on the gut’s ability to signal fullness, and whether those changes revert back to normal by losing weight.

The results, published in the International Journal of Obesity, show that the nerves in the stomach that signal fullness to the brain appear to be desensitized after long-term consumption of a high-fat diet.

“The stomach’s nerve response does not return to normal upon return to a normal diet.  This means you would need to eat more food before you felt the same degree of fullness as a healthy individual,” says study leader Associate Professor Amanda Page from the University’s Nerve-Gut Research Laboratory.

“A hormone in the body, leptin, known to regulate food intake, can also change the sensitivity of the nerves in the stomach that signal fullness.  In normal conditions, leptin acts to stop food intake.  However, in the stomach in high-fat diet induced obesity, leptin further desensitizes the nerves that detect fullness.

“These two mechanisms combined mean that obese people need to eat more to feel full, which in turn continues their cycle of obesity.”

Associate Professor Page says the results have “very strong implications for obese people, those trying to lose weight, and those who are trying to maintain their weight loss”.

“Unfortunately, our results show that the nerves in the stomach remain desensitized to fullness after weight loss has been achieved,” she says.

Associate Professor Page says they’re not yet sure whether this effect is permanent or just long-lasting.

“We know that only about 5% of people on diets are able to maintain their weight loss, and that most people who’ve been on a diet put all of that weight back on within two years,” she says.

“More research is needed to determine how long the effect lasts, and whether there is any way – chemical or otherwise – to trick the stomach into resetting itself to normal.”


This study has been funded by the National Health and Medical Research Council (NHMRC).

Media Contact:

Associate Professor Amanda Page Nerve-Gut Research Laboratory School of Medicine The University of Adelaide Phone: +61 8 8222 5644

New health guidelines: no birthday cake candles allowed for Australian children

Posted By Caroline May On 5:29 PM  02/07/2013 @ 5:29 PM In DC Exclusives,DC Exclusives – Blurb,Uncategorized,World | No Comments

New child-care guidelines from Australian health officials will make blowing out candles on birthday cakes a thing of the past down under.

According to new hygiene rules for child-care centers from Australia’s National Health and Medical Research Council, blowing out birthday cake candle spreads germs and should be avoided.

“Many children like to bring a cake to share with their friends on their birthday,” the guidelines explain. “Children love to blow out their candles while their friends are singing ‘Happy birthday’. Cakes and candles may also be brought into the education and care service for other special occasions.”

The NHMRC advises that to “prevent the spread of germs,” children should blow out a candle on a single piece or a separate cupcake.

Other regulations contained in the nearly 200-page guidance on childcare include regulations on sandbox play (adults and children must wash their hands with soap or sanitizer before and after play), play dough (wash hands before and after, and provide a different untouched batch each day), as well as require child-care centers to wash door handles, cushions, and toys at the end of each day.

While the guidelines are aimed at curbing the spread of illness, the Australian Medical Association has warned against overly sensitive guidance that puts “kids in a bubble,” according to the Sydney Daily Telegraph.

“If you live in a plastic bubble you’re going to get infections [later in life] that you can’t handle,” AMA president Steve Hambleton said, according to the Telegraph. “It’s normal and healthy to be exposed to a certain amount of environmental antigens that build up our immune systems.”

Health Minister Tanya Plibersek, who helped to launch the guidance, said that the proposal is just advice at this point, The West Australian reported.

“They are not rules, and we’re not policing them,” she told ABC Radio in Melbourne.

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The amazing new treatment using COW’S MILK that could prevent HIV

  • Cows can’t  catch HIV but they can produce antibodies against the virus
  • Scientists  injected cows with HIV protein, and collected resulting antibodies from the  milk
  • They plan to  create a cream for women to prevent HIV transmission


PUBLISHED:05:24 EST, 24  October 2012| UPDATED:05:48 EST, 24 October 2012


Cows cannot contract HIV but their immune systems develop antibodies against the foreign protein 

Cows cannot contract HIV but their immune systems  develop antibodies against the foreign protein

Love it or hate it, cow’s milk is an  excellent source of calcium and vitamin D. Now scientists think they can harness  it to protect people from HIV.

Researchers found that cows could be used to  produce antibodies that defend against the human immunodeficiency  virus (HIV). The animals can’t contract the disease themselves.

The next step will be to develop it into a  cream which women can apply to protect themselves from contracting  HIV from  sexual partners.

A team from Melbourne University worked with Australian biotechnology company Immuron  Ltd to develop the milk.

The scientists, led by Dr Marti Kramski,  vaccinated pregnant cows with an  HIV protein and studied the first milk that  cows produced after giving  birth.

The first milk,  called the colostrum, is  naturally packed with antibodies to protect the newborn calf from infections.  The vaccinated cows produced HIV  antibodies in their milk.

‘We were able to harvest antibodies specific  to the HIV surface protein from the milk,’ said Dr  Kramski.

‘We have tested these antibodies and found in  our laboratory experiments that they bind to HIV and that this inhibits the  virus from infecting and entering human cells.’

The HIV-inhibiting antibodies from cows’ milk  will be developed into a cream called a microbicide that is applied into the  vagina before and/or after sex to protect women from contracting sexually  transmitted infections.

Other microbicides are being developed  around the world but the antibodies in this research are easier and  cheaper to  produce, providing a new HIV-prevention strategy.

‘We hope that our anti-HIV milk  antibodies  will provide a user-friendly, female-controlled, safe and  effective tool for  the prevention of sexually acquired HIV infection,’ Dr  Kramski said.

‘If proven effective in humans, it will  empower women to protect themselves against HIV.’

Marti Kramski, left, at the University of Melbourne with frozen milk containing HIV antibodies. Pictured with colleagues Behnaz Heydarchi, middle, and Rob Center 

Marti Kramski, left, at the University of Melbourne with  frozen milk containing HIV antibodies. Pictured with colleagues Behnaz  Heydarchi, middle, and Rob Center

About 30 million people are living with HIV  globally and there is presently no effective vaccine for humans.The research was  supported by the Australian Centre for HIV and Hepatitis Virology Research and  the NHMRC.

Dr Kramski  and her colleagues are now developing plans for animal and human  studies.

The work was being sponsored by Fresh  Science, a national program sponsored by the Australian Government. It is  published in the journal Antimicrobial Agents and Chemotherapy.

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