Articles from:July 2018

• Tiny robot could be game-changer in fight against tuberculosis

  Monday, July 23, 2018 | By Brock University

  MEDIA RELEASE: 23 July 2018 – R00147

  A Brock University research team has created a microscopic robot that has the potential to identify drug resistance to tuberculosis faster than conventional tests.

  The World Health Organization (WHO) calls tuberculosis drug resistance “a formidable obstacle” to treatment and prevention of a disease that killed 240,000 people in 2016.

  The Brock team’s latest technology builds on an earlier version of the microscopic robot — called the three-dimensional DNA nanomachine — they created in 2016 to detect diseases in a blood sample within 30 minutes.

  In this latest version, the team, headed by Assistant Professor of Chemistry Feng Li, re-designed the nanomachine so that it could uncover mutations in the genes found in the bacteria that causes tuberculosis.

  Li says the nanomachine holds the potential to determine, within one hour, whether or not tuberculosis bacteria contain the genetic mutations that make them resistant to the basic, first-line drugs prescribed to fight tuberculosis.

  The WHO says resistance occurs mostly because patients don’t adhere to the strict schedule of antibiotics they need to take to get cured. The bacterial cells’ genes change so that the bacteria can survive future exposures to the same antibiotics, which means a second-line treatment is then required.

  It takes a while before health-care professionals and patients realize the first-line drugs aren’t working, which is why quick detection of drug resistance is so crucial, Li says.

  “Once you confirm there is tuberculosis infection, you have to use the diagnosis to guide the therapeutic strategy,” he says. “Normal infection and drug-resistant strains require two completely different types of strategies.”

  Li says current testing for resistance is an arduous, time-consuming process that can take anywhere from two to six weeks and requires high-level equipment and training. In the meantime, the disease worsens in patients, who can also pass the disease along to others.

  The Brock team’s nanomachine consists of a 20-nanometre particle made out of gold. Short and long DNA strands are attached to the gold particle and these DNA molecules are used as building blocks to construct and operate the nanomachine.

  Graduate student Alex Guan Wang used a computer simulation model to design the long strands, which are able to seek out differences in nucleotides contained within the tuberculosis bacteria’s genes. A nucleotide is the basic structural unit and building block for DNA, and it’s within these that mutations caused by drug resistance would be found.

  The short DNA strands attached to the nanomachine carry fluorescent signal reporters.

  The nanomachine is dropped into serum extracted from human blood. If the long strands detect the mutations found in specific nucleotides, the machine turns on and glows; if the sample is disease-free, the robot remains off.

  Graduate student Yongya Li conducted the lab experiments. She first started the research when she was an undergraduate student.

  The team’s findings are contained in their paper “Simulation-guided engineering of an enzyme-powered three-dimensional DNA nanomachine for discriminating single nucleotide variants,” published June 30 in the journal Chemical Science. Feng Li and his collaborators also produced another research paper in the journal Analytical Chemistry, describing how to modify the nanomachine to detect diseases by examining a number of proteins in samples.

  For more information or for assistance arranging interviews:

  * Dan Dakin, Media Relations Officer, Brock University [email protected], 905-688-5550 x5353 or 905-347-1970

  Brock University Marketing and Communications has a full-service studio where we can provide high definition video and broadcast-quality audio.

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  Categories: Media releases

• Brock geologist leads effort to update Earth’s geologic time scale

  Friday, July 20, 2018 | By Brock University

  MEDIA RELEASE: 20 July 2018  – R00146

  It’s official. More than 8,000 years ago, a vast amount of water from melting glaciers flooded North America and caused havoc with the currents and atmosphere of the North Atlantic.

  That significant event, during the Middle Holocene Northgrippian Age, was followed by droughts and cold temperatures in various parts of the globe that wiped out several civilizations during the Late Holocene Meghalayan Age more than 4,000 years ago.

  Scientists have long known about this history. What’s now official are the geological time periods in which these events occurred.

  Late last month, the International Union of Geological Sciences officially approved three ages of the Holocene epoch: Early Holocene Greenlandian Age; Middle Holocene Northgrippian Age; and Late Holocene Meghalayan Age.

  Laying the groundwork for this sub-division was the International Subcommission on Quaternary Stratigraphy — Quaternary referring to the period under which the Holocene epoch falls.

  Brock University Professor of Earth Sciences Martin Head chairs the subcommission, made up of geologists around the globe. He is also co-author of the academic article that reports these changes to the time scale along with lead author Professor Mike Walker of the University of Wales.

  Head says his group debated a proposal by international Earth experts to sub-divide the Holocene into three ages and determine where to place the so-called “golden spike” at those points where these three sub-divisions occur.

  The golden spike — technically known as the Global Boundary Stratotype Section and Point, or GSSP — is an internationally agreed upon reference point that determines the lower part of a stage, which are rock layers laid down in a single age.

  Now, the Early Holocene Greenlandian Age; Middle Holocene Northgrippian Age; and Late Holocene Meghalayan Age have their own individual golden spikes.

  “The terms early, middle and late Holocene have long been in use, but they’ve never been formally defined,” says Head, adding that a lack of formal definition created some confusion among experts.

  “This is the job of the subcommission, to provide order where none existed before,” he says.

  The Holocene Epoch stretches back to about 11,700 years ago in Earth’s history. It is characterized by events of both warming and cooling temperatures and the resulting changes to sea levels and land masses.

  Rock layers in the Holocene contain sediments from ancient sea floors, lake bottoms, glacial ice and a mineral called calcite, giving researchers many clues as to the occurrence of climate-change related events during the Holocene’s three sub-divisions.

  Head says his subcommission’s formalizing of the three ages solidifies scientists’ knowledge of the Holocene and explains in particular the fall of several civilizations some 4,200 years ago.

  “This event brings together the convergence of global climatic change, archaeological evidence, historical records and societal evolution,” he says. “We’re bringing all this together to form a coherent story that is now reflected in formal geological time. We’re revealing the whole picture here.”

  Head says the Geological Time Scale not only “reflects a narrative of how we understand Earth history,” but also illuminates “the history of humans, and so their story also becomes entwined with the geological record and geological time, and that’s very exciting.”

  The past also sheds light on present trends. Head says the massive flooding that took place 8,200 years ago at the start of the Middle Holocene Northgrippian Age serves as a “warning shot” of how contemporary human-induced climate change can exacerbate melting of ice in the high northern latitudes, causing ocean currents to shift and extreme weather to result.

  Brock Professor of Earth Sciences Martin Head is available to speak about the issue.

  For more information or for assistance arranging interviews:

  * Dan Dakin, Media Relations Officer, Brock University [email protected], 905-688-5550 x5353 or 905-347-1970

  Brock University Marketing and Communications has a full-service studio where we can provide high definition video and broadcast-quality audio.

  – 30 –

  Categories: Media releases