Canadian Health Concerns

There have been a couple of items in the news recently regarding Canadian health issues. Both of them have been touched on before (which should come as no surprise - we're visionaries here at the Bayblab).

The first is Listeria which began with an outbreak which left one dead and several others ill and the subsequent product recall and shutdown of the Toronto Maple Leaf production facility. We've tackled Listeria before, and discussed some of the strategies companies use to minimize contamination - mainly sanitary design and proper cleaning. In the US, bacteriophage are also used for Listeria management. In Canada, we have yet to adopt these measures:

[Retired Health Canada microbiologist and food inspector Bill] Riedel said Canada needs a system like one approved in the United States two years ago, in which bacteriophage therapy is used to combat Listeria monocytogenes found in foods. Bacteriophages are viruses that infect and destroy bacteria.

As of Wednesday, the number of deaths caused by the outbreak was 6, with 10 others under investigation. Major fast-food chains McDonalds and Mr. Sub were affected by the recall. I wonder if bacteriophage technology would have prevented this outbreak, and if the death toll and economic impact will accelerate a move towards it.

Second up is the mumps outbreak in western Canada. I've written about disease resurgance before, usually measles. This time it's mumps. Close to 200 cases have been reported in the Chilliwack region of British Columbia - a province that typically sees no more than 5 cases per year (according to CBC.ca).

Of the 191 cases reported so far since the outbreak began in Chilliwack in February, 10 to 20 are still active. Half of the people who have been infected have not been immunized, a quarter have had at least one shot and a quarter do not have vaccination records, Dr. Brodkin said. One person developed meningitis, nine suffered hearing loss and 26 had swollen testicles or ovaries. It is not clear how many of those cases will result in permanent deafness or sterility.

Officials fear that up to two-thirds of cases are going undetected and continue to spread the virus. The outbreak has been linked to religious groups in the area who are opposed to vaccination due to their beliefs.

There's Bacteriophage in my Bologna

Listeria is a bacterial contaminant of food and while infection is rare, it has a higher mortality rate than Salmonella. Infection may be rare, but the bacteria itself isn't and it can grow at low temperatures, meaning even when refrigerated Listeria can multiply on contaminated food. Of particular concern are foods that aren't cooked or reheated before eating - like the bologna or deli-sliced ham on your sandwich at lunch. Two recent scares at New Zealand hospitals have lead to quarantine of certain ready-to-eat foods after positive Listeria tests as a precautionary measure.

But if Listeria is everywhere and it persists under normal food storage conditions, why aren't infections more common? Well, for one thing, companies do their utmost to eliminate bacterial growth niches in their processing plants - especially after a "kill" step (eg. cooking) - by sanitary design (eliminating nooks and crannies that are difficult to clean) and proper cleaning, followed by other quality control testing. In 2006 (old news, I know), the FDA approved another tool for use in an anti-Listeria arsenal: bacteriophage.

Bacteriophage are bacteriolytic viruses and have a history of use as an antibiotic in the Soviet Union and Eastern Europe. Bacteriophage is the bane of some food making (and other) processes - those based on bacterial fermentation, such as yogurt production. For Listeria management it was approved and recognized as a safe food additive by the FDA in August, 2006. The phage used is a mix of 6 different forms used to target different Listeria strains and to minimize development of resistance. The phages themselves are grown in Listeria and purified before being applied just prior to packaging. The FDA has a FAQ about the bacteriophage additive. (Unfortunately I couldn't find any information about phage use in Canadian food manufacturing, or if there was an uproar in the US when the decision was made) This decision opened the door for other phage uses in the food industry, such as controlling E. coli or Salmonella in a similar way. The designation as 'safe' may also help resurrect the idea of using bacteriophages as antibiotics, particularly to combat emerging superbugs (MRSA).

So there you have it - that turkey sandwich you had for lunch may be a turkey and phage sandwich, so keep it away from your probiotic yogurt.

Mitochondrial Madness

Our often-neglected bacterial endosymbionts the mitochondria seem to have their fingers in all aspects of eukaryotic cell functioning. Not only do they make us ATP and tell our cells when to die, they even have their own genome, which they can replicate, transcribe and translate all on their own. But mitochondria don't just use proteins encoded in their own genomes; they've also got some out on loan from the nucleus. And this is where the madness begins. Somehow this excellent Molecular Cell review on mitochondrial transcription found its way onto my lab bench, so I read it. Here are a few of the mind-blowing facts you can discover therein:

• The eukaryotic single-subunit mitochondrial RNA polymerase was ganked from bacterial viruses (bacteriophage T3/T7), and has no relation to those encoded by bacteria themselves.

• Even weirder, the phage-like mtRNA polymerase is encoded in the nuclear genome of eukaryotes. Interstingly, an isoform of mtRNA polymerase lacking a mitochondrial localization signal performs transcription of nuclear-encoded genes in the nucleus (RNA pol IV).

• The amino-terminal domain of yeast mtRNA polymerase has diverged from its phage ancestry, and has evolved to mediate coupling between mitochondrial transcription and translation. In fact, mutations in the ATD lead to deficiencies in mitochondrially-encoded OXPHOS enzymes and thereby decrease lifespan in yeast.

• What? Mitochondrial translation? What's up with that? Nobody really knows...

Also, check out this wicked album of artistic renditions of cells by Gary Carlson which I ganked the above photo from. Nice job Gary!