Daily Archives: February 22, 2017

Cornell researchers have found that salmonella-induced food poisoning could permanently damage your DNA(Credit: iLexx/Depositphotos)

A bad bout of food poisoning will knock you off your feet, but a few days later you'll hopefully be back to your old self like nothing ever happened. But new research from Cornell University suggests that certain types of salmonella, one of the main bacterial causes of food poisoning, can have much longer-lasting effects. In some cases it could actually cause permanent damage to your DNA, leaving you more vulnerable to illness in the future.

According to the CDC, salmonella is responsible for about a million cases of food-borne illnesses in the US every year, but it's rarely deadly. Less than 400 of those infected will die from the illness, with the rest usually recovering by themselves in a few days or a week.

At the center of the Cornell study was the salmonella serotype, Typhi, the bug that causes typhoid fever. Typhi produces cytolethal distending toxin (S-CDT), a substance that's known to attack the cells of its host and damage DNA. The researchers examined other strains of salmonella, including common food-poisoners like Javiana, Montevideo, Oranienburg and Mississippi, and found that they also have the potential to express S-CDT.

When the team tested the effects that these S-CDT-producing bacteria have on lab-grown human cells, they found clear signs of DNA damage. While the researchers don't fully know what the run-on effects such damage can have on the body, it could make future food-borne illness episodes last longer.

"Think about possible DNA damage this way: We apply sunscreen to keep the sun from damaging our skin," explains Rachel Miller, author of the study. "If you don't apply sunscreen, you can get a sunburn and possibly develop skin problems later in life. While not the sun, salmonella bacteria may work in a similar way. The more you expose your body's cells to DNA damage, the more DNA damage that needs to be repaired, and there may one day be a chance that the DNA damage is not correctly repaired. We don't really know right now the true permanent damage from these salmonella infections."

The research was published in the journal mBio.

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Can food poisoning permanently damage your DNA? - New Atlas

Modesto Bee

DNA, shoe print analysis fail to link murder trial defendant to crime scene Modesto Bee California Department of Justice officials on Tuesday testified that an analysis of DNA evidence and a shoe print failed to link Carlos Ivan Flores to the scene of a 2015 deadly home-invasion robbery in west Modesto. Flores is on trial, accused of ...

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DNA, shoe print analysis fail to link murder trial defendant to crime scene - Modesto Bee

February 21, 2017

An international collaboration of life scientists, including experts at Van Andel Research Institute, has described in exquisite detail the critical first steps of DNA replication, which allows cells to divide and most advanced life, including human, to propagate.

Results of the study are published in the journal Nature Structural and Molecular Biology and reveal that a ring-shaped protein called origin recognition complex (ORC) possesses a special alpha-helix, which slips into a groove on DNA and initiates a cascade of microscopic interactions that copy DNA.

"This is a story of one ring that lords over another ring," says Huilin Li, Ph.D., a professor in Van Andel Research Institute's Center for Epigenetics and a senior author of the paper. "Biologists have known for many years that both ORC and helicase are ring-shaped structures essential in the initiation and execution of DNA replication, but until now we never understood exactly how the ORC ring loads the helicase ring onto DNA."

The work also reveals that ORC, with the help of Cdc6 and Cdt1, loads the helicase core onto DNA via paired interactions of the so-called winged helix domains. The resulting 14-protein structure completes the loading of the first helicase ring and is now prepared to load the next ring.

This process represents the inception of an immensely complex and elegant system that is constantly ongoing at tens of thousands of points on the DNA in many cells of the human body, and it all starts with ORCs.

"We hope that by mapping this process, others will eventually convert this knowledge into new treatments for DNA replication-related conditions, including many cancers and rare disorders," says Li.

At the outset, the six-protein ORCs assemble into a crescent, which envelops the DNA duplex. The ORCs then recruit a seventh protein, called Cdc6, to encircle DNA. Next, this ring threads the second ring, called minichromosome maintenance protein (Cdt1-bound Mcm2-7 hexamer), around DNA, which completes loading of the first Mcm2-7 hexamer.

"It's like threading a pearl onto a string; but unlike a short piece of string, the DNA strand is incredibly long and so the bead cannot be threaded on at one end," says Christian Speck, a professor at Imperial College of London's Institute of Clinical Sciences, leader of the DNA Replication group at MRC London Institute of Medical Sciences and a senior author of the paper. "Instead, it must somehow be opened up, slotted around the strand, and closed again."

The study was conducted on the DNA of Saccharomyces cerevisiae, better known as baker's yeast, because of its biological and genomic similarity to larger organisms, including mammals, at an average resolution of 3.9 Angstrms (about 40 billionths of a meter), which is roughly the diameter of a single atom of sodium.

Magnification of this scale is currently possible only with cryoelectron microscopy (cryo-EM), a revolutionary technology VARI continues to invest in through its recently established Cryo-EM Core. Imaging for this study was conducted at Howard Hughes Medical Institute's Janelia Research Campus and at Scripps Research Institute.

Explore further: New study reveals the structure of DNA helicase at the replication fork

More information: Zuanning Yuan et al. Structural basis of Mcm27 replicative helicase loading by ORCCdc6 and Cdt1, Nature Structural & Molecular Biology (2017). DOI: 10.1038/nsmb.3372

Scientists at Van Andel Research Institute and Rockefeller University have successfully described a crucial structure involved in DNA replication, placing another piece in the puzzle of how life propagates.

In a study published today in Genes & Development, Dr Christian Speck from the MRC Clinical Sciences Centre's DNA Replication group, in collaboration with Brookhaven National Laboratory (BNL), New York, reveal the intricate ...

For years, scientists have puzzled over what prompts the intertwined double-helix DNA to open its two strands and then start replication. Knowing this could be the key to understanding how organisms - from healthy cells to ...

Building on earlier work exploring the complex choreography by which intricate cellular proteins interact with and copy DNA prior to cell division, scientists at the U.S. Department of Energy's Brookhaven National Laboratory ...

In the second part of his lab's recent one-two punch, Florida State University researcher Daniel Kaplan said he has solved a cell division mystery in a way that will intrigue the makers of cancer-fighting drugs.

The proteins that drive DNA replicationthe force behind cellular growth and reproductionare some of the most complex machines on Earth. The multistep replication process involves hundreds of atomic-scale moving parts ...

Beetles that copulate with the same mate as opposed to different partners will repeat the same behaviour, debunking previous suggestions that one sex exerts control over the other in copulation, new research has found.

They build among the tallest non-human structures (proportionately speaking) in the world and now it's been discovered the termites that live in Australia's remote Top End originated from overseas - rafting vast distances ...

A Rice University study suggests that researchers planning to use the CRISPR genome-editing system to produce designer gut bacteria may need to account for the dynamic evolution of the microbial immune system.

An international collaboration of life scientists, including experts at Van Andel Research Institute, has described in exquisite detail the critical first steps of DNA replication, which allows cells to divide and most advanced ...

For decades, scientists working with genetic material have labored with a few basic rules in mind. To start, DNA is transcribed into messenger RNA (mRNA), and mRNA is translated into proteins, which are essential for almost ...

Researchers have discovered a key gene that influences genetic recombination during sexual reproduction in wild plant populations. Adding extra copies of this gene resulted in a massive boost to recombination and diversity ...

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Study details ringed structure of ORC in DNA replication - Phys.org - Phys.Org

Cisco today announced a variety of hardware, software and services designed to increase network virtualization and bolster security for campus, branch office and cloud customers.

The products, which include a Network Functions Virtualization branch office device and improved security network segmentation software, fall under Ciscos overarching Digital Network Architecture plan. DNA offers integrated networking softwarevirtualization, automation, analytics, cloud service management and security under a single suite.

+More Cisco News on Network World: Cisco reserves $125 million to pay for faulty clock component in switches, routers+

DNA offers IT leaders a blueprint for building digital ready networks. In just under 18 months we have seen over1,900 organizations deploy our SDN controller, APIC-EM, in their networks and start laying a foundation capable of enabling their digital transformation, said Ciscos Prashanth Shenoy, vice president of marketing, Enterprise Networking and Mobility.

On the hardware side, Cisco rolled out the Enterprise Network Compute System (ENCS) 5400 Series, a 1RU Intel Xeon server that includes an eight-port GE Switch which supports LTE, T1, DSL and more, as well as Dual-Phy Gigabit Ethernet WAN connectivity and 64Gb of memory.

The 5400 a purpose-built branch platform aimed at helping customers accelerate their Enterprise NFV deployments by extending routing, security, WAN optimization and other network services to their branch environments, Shenoy said.

The 5400 is all about the speed and agility in setting up a branch office rollout that secures virtualized services," Shenoy said. A branch office that took days to set up and provision previously can now be done virtually in minutes with security, QoS and management capabilities.

Cisco does offer other SD-WAN packages and the 5400 is another option but one that focuses on customers interested in virtualizing network functions, experts said.

For security, Cisco extended its TrustSec security software across all its network components and offers security segmentation to isolate attacks and restrict threats in the network.

TrustSec 6.1 now extends from the campus to the branch office and the cloud, all in an effort to avoid and prevent pervasive threats Shenoy said.

In that vein, Cisco also enhanced its Identity Services Engine (ISE). ISE 2.2 offers much deeper visibility into applications on endpoints, including detection of anomalous behavior. It also offers more granular control with the ability to define "DEFCON" policy sets that lets customers escalate their response to prolific threats, Shenoy stated.

Together ISE and TrustSec can help turn the network into a sensor and enforcer, Cisco said. ISE provides visibility and control of users and devices on the network, while TrustSec provides software-defined segmentation to isolate attacks and restrict movement of threats in the network.

Rather than changing the authorization of individual users and devices, or implementing policy changes manually, changing DEFCON state changes the TrustSec policies defining how users, devices, and systems can talk to others essentially raising the network drawbridges to protect your critical data and maintaining essential services. For example, you could define DEFCON 4 to kick all guests off the network, DEFCON 3 to kick all BYOD users off the network, DEFCON 2 to restrict peer-to-peer traffic, and DEFCON 1 to severely limit access to your crown jewels, wrote Kevin Skahill, director, product management in Ciscos Secure Access and Mobility Product Group in a blog detailing the new security software.

ISE 2.2 also provides streamlined workflows that include guest, secure access, and BYOD setup with Cisco Wireless LAN Controllers in as little as 10 minutes. This approach also extends to customers migrating from the Cisco Access Control System (ACS), which Cisco recently announced will go end-of-sale, Skahill stated.

On the services side, Cisco announced an online DNA Advisor and network assessment tool that helps customers define their digital network. The company also announced DNA Advisory Services that will offer in-depth consulting to help enterprises formulate a digital strategy.

Cisco dovetailed the DNA announcement with the release of a study that looked at the issues surrounding what it calls digital-ready networks. Conducted by IDC and commissioned by Cisco, the research surveyed 2,054 global organizations across 10 countries to determine the digital readiness of their networks. A couple findings from the study included:

Outdated infrastructure characteristics such as manual configuration and management processes, overlay security geared mainly toward external threats, and siloed network domains hinder the networks ability to further the goals of digital business. For IT staff, valuable time is spent keeping the lights on instead of aligning network capabilities with strategic initiatives that improve operational efficiency and enhance customer experience. A network that is truly digital ready is a network that can dynamically align with the ever-changing needs of the enterprise. That means a network that allows more agility and faster time to innovation, better security, and greater operational efficiency and simplicity, IDC wrote.

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Cisco deepens enterprise network virtualization, security detection of DNA suite - Network World