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Archive - Nov 13, 2013

Fungus Kills Ticks, May Benefit Sheep

Ticks may be facing a dangerous fate. In the TICLESS project, Bioforsk, the Norwegian Institute for Agricultural and Environmental Research, is hoping to determine whether fungus can kill ticks in sheep pastures, according to a November 12, 2013 press release. This would also benefit future hikers. Tick bites in sheep can lead to the disease tick-borne fever (TBF), which causes high fever and weakens the immune system. As a result of TBF, animals may become seriously ill from diseases they usually cope with. Bioforsk is therefore conducting field trials where the aim is to reduce tick populations in sheep grazing areas by using a tick pathogenic fungus called Metarhizium. Metarhizium occurs naturally in Norwegian soil and in the soils of many other countries worldwide where it has the potential to infect and kill ticks. When living organisms or "natural enemies" of a pest are utilized in order to reduce pest population levels, this is known as biological control. Dr. Ingeborg Klingen, Head of the Section of Invertebrate Pests at Bioforsk Plant Health and Plant Protection Division, and her group, are currently conducting field trials with BIPESCO 5 which is a formulation of an isolate of the tick pathogenic fungus, Metarhizium. “The fungus we are using in the trial is a natural enemy of insects and mites found in soil. What we do is to increase the natural fungal population by releasing it in large quantities. This type of biological control is known as augmentation biological control and is an alternative to chemical control”, says Dr. Klingen. “The death that awaits ticks exposed to this fungus, is inhumane; fungal spores land and germinate on the skin (cuticle) of the tick and then penetrate it before entering the tick body. The fungus then grows and proliferates inside the tick.

Engineered Fusion Protein Opens Door for Safer Gene Therapy‬

A protein engineered by researchers at KU Leuven that combines proteins active in HIV and Moloney murine leukemia virus (MLV) replication may lead to safer, more effective retroviral gene therapy. KU Leuven is located in Flanders, the Dutch-speaking region of Belgium. Gene therapy involves inserting healthy genetic material into a diseased cell. Using a carrier derived from a retrovirus, the genetic material is smuggled into a human cell where, once inside, it integrates itself into the cell’s DNA. But gene therapy is not without risks. If integrated too near a carcinogenic gene, the newly introduced genetic material can also induce disease-causing mutations. In gene therapy, the delivery vehicle is not the retrovirus itself, but a viral vector: a derivative form of the retrovirus that retains its proteins but not its nucleic acid. One of the most widely used viral vectors is derived from MLV. But this particular virus-borne carrier is both a weapon and a risk. It can cure disease but, if integrates in the wrong place in a cell’s DNA, it can also cause leukemia. A separate protein, which plays a role in HIV, does not have that problem. It only integrates itself in ‘safe’ places in the host cell’s DNA. The researchers put one and two together to create a safer viral vector: “We developed a fused protein with the head of the protein that HIV uses and the tail of the protein that MLV uses,” Dr. Rik Gijsbers explains. Their work was reported online on October 31, 2013 in Cell Reports, and the researchers say their engineered retroviral vector works: “Our experiments with cell cultures show that in the presence of this protein, the viral vector always inscribes itself in a safe place, just as it does in the HIV virus,” says Dr. Gijsbers.

Thin Invisibility Cloak Demonstrated for First Time

Invisibility cloaking is no longer the stuff of science fiction: two researchers in The Edward S. Rogers Sr. Department of Electrical & Computer Engineering have demonstrated an effective invisibility cloak that is thin, scalable and adaptive to different types and sizes of objects. Professor George Eleftheriades and Ph.D. student Michael Selvanayagam have designed and tested a new approach to cloaking—by surrounding an object with small antennas that collectively radiate an electromagnetic field. The radiated field cancels out any waves scattering off the cloaked object. Their paper was published online on November 12, 2013 in an open-access article in Physical Review X. “We’ve taken an electrical engineering approach, but that’s what we are excited about,” says Professor Eleftheriades. “It’s very practical.” Picture a mailbox sitting on the street. When light hits the mailbox and bounces back into your eyes, you see the mailbox. When radio waves hit the mailbox and bounce back to your radar detector, you detect the mailbox. Eleftheriades and Selvanyagam’s system wraps the mailbox in a layer of tiny antennas that radiate a field away from the box, cancelling out any waves that would bounce back. In this way, the mailbox becomes undetectable to radar. “We’ve demonstrated a different way of doing it,” says Professor Eleftheriades. “It’s very simple: instead of surrounding what you’re trying to cloak with a thick metamaterial shell, we surround it with one layer of tiny antennas, and this layer radiates back a field that cancels the reflections from the object.” Their experimental demonstration effectively cloaked a metal cylinder from radio waves using one layer of loop antennas.

Transcription Factor Study Yields Insight

In order to react effectively to changes in the surroundings, bacteria must be able to quickly turn specific genes on or off. Although the overall mechanisms behind gene regulation have long been known, the fine details have eluded scientists for decades. Researchers at Uppsala University in Sweden can now provide a picture of how proteins regulate genetic expression at the atomic level. Genes can be regarded as blueprints for all of the molecular machines—normally proteins—that perform the tasks an organism needs for survival. Under different living conditions, different types of proteins are needed to break down the available types of nutrients, for example. Because the surroundings can change rapidly, it is also important for bacteria and other organisms to be able to quickly reconfigure their biochemical operations in order to adapt to the new environment. This is done through regulation of the activity of proteins that already exist in the cell, but also by the binding of special proteins—transcription factors—to specific sites on the DNA, turning certain genes on or off, which in turn regulates the cell's production of various proteins. The latter might seem impossible, as an arbitrary transcription factor normally exists in just a handful of copies inside a bacterial cell, and one of them has to find a specific binding site on the DNA spiral, which contains some five million base pairs, in order to turn a gene on or off, says Dr. Erik Marklund, one of the lead authors of the new study. Roughly 40 years ago, it was observed that these transcription factors find their binding sites on DNA much more quickly than free diffusion in three dimensions would allow.