Tag Archives: transport

We’re all hosts on a viral planet: yes, bacteria too

Posted on by
Reply

Given that phages are able to destroy bacteria, they are of particular interest to science. Basic researchers from the Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) in Berlin are especially interested in the tube used by phages to implant their DNA (or RNA – dp) into bacteria. In collaboration with colleagues from Forschungszentrum Jülich and Jena University Hospital, they have now revealed the 3D structure of this crucial phage component in atomic resolution. The key to success was combining two methods – solid-state NMR and cryo-electron microscopy. The study has just been published in the journal Nature Communications.

With growing antibiotic resistance, phages have increasingly become the focus of research. Phages are naturally occurring viruses with a very useful property: they implant their DNA into bacteria and proliferate there until the bacterial cell is ultimately destroyed. This is why they are also referred to as bacteriophages (bacteria eaters).
This approach has already been shown to fight multidrug-resistant bacteria. Last year, the case of a girl from England hit the headlines, when she was cured from a serious antibiotic-resistant infection using engineered phages.

However, the widespread use of phage therapy is still a long way off. Many of the underlying principles that are key to advancing this therapy are not yet understood. For example, little was previously known about the appearance of the exact architecture of the tube used by phages to implant their DNA into bacteria. Now scientists from the Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) in Berlin, together with colleagues from Forschungszentrum Jülich and Jena University Hospital, have managed to reveal the 3D structure of this crucial phage component in atomic resolution.

“The structure and flexibility of the DNA tube attached to the icosahedron-shaped capsid is somewhat reminiscent of a spinal column,” stated FMP’s Professor Adam Lange, describing one of the new findings. “It seems to be perfectly designed for transporting DNA.”

The researchers were able to gain insights into the structure and function of this sophisticated DNA transport pathway – in this case, from a variant of phage SPP1 – by combining solid-state NMR with cryo-electron microscopy (cryo-EM). Lange’s research group further developed nuclear magnetic resonance spectroscopy (NMR) especially for this task under an ERC Grant; cryo-EM expert Professor Gunnar Schröder from Forschungszentrum Jülich performed the electron-microscopic investigations. In addition, new modeling algorithms were required for the computer-based combination of the two data sets for structure determination. These algorithms were developed by Professor Michael Habeck from Jena University Hospital. “The key to success was combining the two methods, representing a methodological milestone,” commented Professor Lange.

While solid-state NMR is ideal for visualizing flexible structures and tiny details, cryo-EM provides insight into the overall architecture. The resulting image shows that six gp17.1 proteins organize into stacked rings, forming a hollow tube. The rings are connected by flexible linkers, making the tube very bendable. “We are now able to understand how negatively charged DNA is repelled from the likewise negatively charged interior wall of the flexible tube, passing through it smoothly,” explained FMP’s Maximilian Zinke, lead author of the study now published in Nature Communications. “The bacteria are ultimately destroyed via this pathway.”

EFSA advises on meat spoilage during storage and transport

Posted on by
Reply

Continuing in the advice vein, the European Food Safety Authority is trying to balance safety and quality when transporting meat.

meat.and.you.simpsonsEFSA had previously advised on the implications for meat safety if two parameters – time and temperature – varied and provided several scenarios for ensuring safety of meat during storage and transport of meat. The Commission subsequently asked EFSA to consider what implications such scenarios would have for the growth of bacteria that cause meat to spoil.

“If the sole consideration was safety, policy makers would have more options on the table to pick from. However, scenarios that are acceptable in terms of safety may not be acceptable in terms of quality,” said Dr. Marta Hugas, Head of EFSA’s Biological Hazards and Contaminants unit.

Current legislation requires that carcasses are chilled to no more than 7C and that this temperature is maintained until mincing. The European Commission wants to revise this legislation to provide industry with more flexibility and asked EFSA’s scientific advice on safety and quality aspects.

Experts also said that effective hygienic measures during slaughter and processing help control contamination with spoilage bacteria.

‘I recognize long-haired employee’ Winnipeg delivery of pig carcasses sparks provincial investigation

Posted on by
Reply

CBC News reports that Manitoba health authorities are investigating after photos of pig carcasses which appear to have been improperly handled during deliveries to two Winnipeg businesses surfaced on social media.

pigs-two“The first thing that popped out from the pictures in my mind was that the meat, the quarter and half sections of pork, had been thrown on the floor of the truck,” said Rick Holley, a University of Manitoba food safety expert. “You can see there are some non-meat items which are also on the floor of the truck.”

The photos were posted to a public Facebook page and obtained by CBC news. They show two trucks delivering half and quarter pork carcasses to businesses at 303 King Street in Chinatown.

The owner of a butcher shop in the building declined an interview, but told CBC News he recognized the long-haired employee in the photos and said he works for one of their suppliers, a Portage la Prairie abattoir.

‘Middle of food chain matters’ Pennsylvania taking temperatures of trucks hauling food

Posted on by
3

A few weeks ago, state agriculture inspectors forced a trucker to toss 2,000 pounds of food in the garbage after finding the cargo had not been kept at safe temperatures.

manufactured cheese on pallets in back of truckFederal rules specify meat and dairy products be trucked at less than 40 degrees. The trucker stopped May 28 near New Castle was carrying a cargo — including meat — at 63 degrees, agriculture department spokeswoman Samantha Krepps said.

He already had delivered to seven restaurants in eastern Ohio and was headed to six more in the Sharon and New Castle areas, Krepps said.

Pennsylvania officials notified their Ohio counterparts, who forced the restaurants there to discard the food, said Lydia Johnson, director of the agriculture department’s bureau of food safety.

The incident, regulators fear, reflects a larger problem, as rising fuel prices create an incentive for shippers to cheat on food safety.

For the past year, state police and agriculture inspectors have been stepping up checks of refrigerated trucks.

Trucks handle 80 to 90 percent of food consumed in the United States, but state police Col. Frank Noonan said relatively little attention has been paid to monitoring the safety of food in transit.