The nano-channel that disentangles knots

A new method to disentangle DNA is being explored at SISSA

2013-02-20

(Press-News.org) The DNA, just like hair, has a tendency to become knotted, thus it may be useful to disentangle it.

Unfortunately, it is not possible to "actively" choose at random (or better, in one solution) the filaments with the desired features, and this is why scientists adopt "passive" solutions like, for instance, having the DNA pass through nano-pores or nano-channels.

"Channels and filaments have physical features we may exploit to selectively let a type of molecule pass through" explains Micheletti. "You can have more or less entangled filaments and featuring knots of different types. In our study we have considered a specific DNA filament model and examined its behavior within a nano-channel. We have observed that by varying the channel's width it is possible to drastically change the quantity and complexity of the knots formed by the DNA."

The nano-channels may therefore be a tool with a double function: on one side they are used to understand the "knotting pattern" of a DNA fragment, on the other they may be used to select entangled filaments in the desired manner. The sectors employing DNA, mainly in sequencing, require an increasing number of new techniques to select the DNA filaments according to their characteristics, such as length, shape as well as entanglement.

More in detail...

"Experimental physicists will be, in the first instance, interested is such technique to obtain knot-free DNA", explains Micheletti referring to the usefulness of the methodology (that for now has been studied through simulation). "We should not forget that such method may also help us better understand, for instance, the functioning of topoisomerases, enzymes that have a very important role in cell metabolism."

Such enzymes play a key role in an organism: they maintain the DNA stretched out when the cell is not undergoing the cell division process.

"We are used to envisage chromosomes in their typical rod shaped appearance, the one preceding mitosis, that is to say cell reproduction," adds Micheletti. "However, usually the DNA is a sort of indistinct bundle that fills up the cell's nucleus. The topoisomerases maintain the disentangled filaments with the lowest possible rate of knotting, and do so by snipping and reattaching the little pieces of genetic material." Only on the "disentangled" filament all those transcription processes which are fundamental to the survival of an organism can actually function.

"The functioning of such enzymes may be better grasped if, before having them perform, we already know to what extent the molecule was entangled in the first place, and our methodology may be useful to this purpose." concludes Micheletti.

INFORMATION:

[Attachments] See images for this press release:

ELSE PRESS RELEASES FROM THIS DATE:

New technology in the magnetic cooling of chips

2013-02-20

Luis Hueso, the CICnanoGUNE researcher, together with researchers from the University of Cambridge, among others, has developed a new technology in the magnetic cooling of chips based on the straining of materials. Compared with the current technologies, this advance enables the impact on the environment to be lessened. The work has been published recently in the prestigious journal Nature Materials. Current cooling systems, be they refrigerators, freezers or air conditioning units, make use of the compression and expansion of a gas. When the gas is compressed, it changes ...

A self-healing protective coating for concrete

2013-02-20

Scientists are reporting development of what they describe as the first self-healing protective coating for cracks in concrete, the world's most widely used building material. Their study on the material — which is inexpensive and environmentally friendly — appears in the journal ACS Applied Materials & Interfaces. Chan-Moon Chung and colleagues explain that protecting concrete roads, bridges and other structures from developing tiny cracks has been a major technological challenge. Cracks allow water, salt used for deicing and air to enter the concrete. During winter ...

New IOM report highlights PEPFAR's successes

2013-02-20

WASHINGTON -- The President's Emergency Plan for AIDS Relief (PEPFAR) has saved and improved millions of lives worldwide and offered proof that HIV/AIDS services can be effectively delivered on a large scale even in countries with high rates of disease and resource constraints, says a new congressionally mandated evaluation conducted by the Institute of Medicine. Moving forward, PEPFAR needs to intensify efforts to help its partner countries develop the capacity to manage their own programs, sustain the gains that have been made in controlling the HIV epidemic, and improve ...

New imaging device that is flexible, flat, and transparent

2013-02-20

WASHINGTON, Feb. 20, 2013— Digital cameras, medical scanners, and other imaging technologies have advanced considerably during the past decade. Continuing this pace of innovation, an Austrian research team has developed an entirely new way of capturing images based on a flat, flexible, transparent, and potentially disposable polymer sheet. The team describes their new device and its possible applications in a paper published today in the Optical Society's (OSA) open-access journal Optics Express. The new imager, which resembles a flexible plastic film, uses fluorescent ...

Can insurers save money by providing free diabetes-related medications and supplies?

2013-02-20

New Rochelle, NY, February 20, 2013–Reducing financial barriers to medication access—a strategy known as value-based insurance design (VBID)—can improve medication adherence and management of chronic diseases such as diabetes. The economic and patient-perceived benefits of eliminating co-payments for diabetes-related medications and supplies are described in a trend-setting study published in Population Health Management, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free on the Population Health Management website at http://www.liebertpub.com/pop. In ...

Ancient 'Egyptian blue' pigment points to new telecommunications, security ink technology

2013-02-20

A bright blue pigment used 5,000 years ago is giving modern scientists clues toward the development of new nanomaterials with potential uses in state-of-the-art medical imaging devices, remote controls for televisions, security inks and other technology. That's the conclusion of an article on the pigment, Egyptian blue, in the Journal of the American Chemical Society. Tina T. Salguero and colleagues point out that Egyptian blue, regarded as humanity's first artificial pigment, was used in paintings on tombs, statues and other objects throughout the ancient Mediterranean ...

6 in 10 people worldwide lack access to flush toilets or other adequate sanitation

2013-02-20

It may be the 21st century, with all its technological marvels, but 6 out of every 10 people on Earth still do not have access to flush toilets or other adequate sanitation that protects the user and the surrounding community from harmful health effects, a new study has found. The research, published in ACS' journal Environmental Science & Technology, says the number of people without access to improved sanitation is almost double the previous estimate. amie Bartram and colleagues explain that the current definition of "improved sanitation" focuses on separating humans ...

Trustworthy mating advice deepens bond between straight women and gay men

2013-02-20

Why do straight women and gay men form close relationships with one another? A new psychology study from The University of Texas at Austin suggests the glue that cements these unique relationships is honest, unbiased relationship advice. The study, published online in the February issue of Evolutionary Psychology, is the first to provide empirical evidence that the emotional closeness shared by straight women and gay men is rooted in the absence of deceptive mating motivations. "Friendships between straight women and gay men are free of hidden mating agendas," says ...

Preclinical study shows potential of new technologies to detect response to cancer therapy earlier

2013-02-20

The research was published early in the January issue of the journal Technology in Cancer Research and Treatment. The article describes experiments using ultrasonic molecular imaging (USMI) and Dynamic Contrast Enhanced-Perfusion Imaging (DCE-PI) to measure response to therapy for pancreatic cancer. Paul Dayton, PhD, senior author says, "What we found is that using two non-invasive technologies, we can detect response to therapy earlier than by relying on tumor volume changes. Having new non-invasive, inexpensive technologies available to measure response to therapy earlier ...

Pitt study examines cost-effectiveness of medicare drug plans in schizophrenia and bipolar disorder

2013-02-20

PITTSBURGH, Feb. 19, 2013 – A new study published online today in the American Journal of Managed Care found that in Medicare Part D, generic drug coverage was cost-saving compared to no coverage in bipolar disorder and schizophrenia, while also improving health outcomes. Researchers from the University of Pittsburgh School of Medicine, the Pitt Graduate School of Public Health, and Western Psychiatric Institute and Clinic of UPMC note that policymakers and insurers should consider generic-only coverage, rather than no gap coverage, to both conserve health care resources ...

The nano-channel that disentangles knots

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: