Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UMass Amherst Researchers Unravel Secrets of Parasites’ Replication

11.07.2012
A group of diseases that kill millions of people each year can’t be touched by antibiotics, and some treatment is so harsh the patient can’t survive it.
They’re caused by parasites, and for decades researchers have searched for a “magic bullet” to kill them without harming the patient. Now, a team of microbiologists at the University of Massachusetts Amherst has made an advance that could one day lead to a new weapon for fighting parasitic diseases such as African sleeping sickness, chagas disease and leishmaniasis.

In the cover article of the current issue of Eukaryotic Cell, parasitologists Michele Klingbeil, doctoral candidate Jeniffer Concepción-Acevedo and colleagues report the first detailed characterization of the way key proteins in the model parasite Trypanosoma brucei organize to replicate its mitochondrial DNA (mtDNA). Understanding this spatial and temporal coordination could mean a foot in the door to launch new attacks on one of the parasites’ essential cell processes, Klingbeil says.

She adds, “Parasites such as T. brucei, which causes African sleeping sickness, are not straightforward to treat because they’re too much like our own cells. Antibiotics are ineffective, so we treat them as invaders, with toxic chemicals. We are trying to find their weaknesses so we can exploit those and eventually develop a very selective, effective and acceptable treatment.”

Advances have not come easily, in part because these parasites have the most complex mitochondrial genome structure in nature, say Klingbeil and Concepción-Acevedo, the lead researcher on the project. To tackle it, they’ve focused on the trypanosome parasites’ extremely complex method of mtDNA replication, which involves kinetoplast DNA or kDNA. Its core components are very unlike DNA replication in animals and human hosts, Klingbeil says, “so if we can inhibit the replication process and take away the kDNA, the parasites will die. That’s one way we might be able to kill them.”

Trypanosomes’ kDNA is found as a nucleoid in the mitochondrion, where it holds many copies of catenated or networked minicircles and maxicircles that look like medieval chain mail under the microscope. These molecules pass information on to daughter cells via DNA polymerases whose job it is to copy all circles in the network. Trypanosomes have six mtDNA polymerases, while humans have just one.

To figure out how these trypanosomal polymerases know when to initiate DNA replication, Concepción-Acevedo set up immunofluorescence experiments focused on tracking a particular one, known as mtDNA polymerase ID (POLID). By fluorescent labeling the POLID protein and tracking it over space and time, Concepción-Acevedo quantified it and clarified its relationship to the overall replication process for the first time in a very discrete time window. The approach immediately paid off.

Klingbeil says, “As soon as Jeny began looking more closely at POLID localization she discovered a novel mechanism for how this protein participates in kDNA replication.” In response to kDNA changes during the replication cycle, POLID was dynamically redistributing, or changing location, from the mitochondrial matrix to concentrated foci around the kDNA, and co-localizing with replicating kDNA molecules.

“This had been hypothesized, but never seen before,” Klingbeil explains. It was amazing to witness. We visualized a mitochondrial replication protein undergoing dynamic localization for the first time, and linked it to DNA synthesis. No one had ever been able to do that in any mitochondrial DNA replication system before.”

This important discovery explains how POLID engages in kDNA replication and opens up new avenues to study and intervene in mitochondrial protein dynamics, say the two parasitologists. Their ultimate success would be to find a chemical to inhibit POLID from carrying out its role during replication and target all parasites with kDNA structures.

This work was funded by the National Institutes of Health’s National Institute of Allergy and Infectious Diseases. Support for Concepción-Acevedo also came from NSF’s Northeast Alliance for Graduate Education and the Professoriate program.

Link to Eukaryotic Cell cover story: http://ec.asm.org/content/11/7.cover-expansion

Janet Lathrop | EurekAlert!
Further information:
http://www.umass.edu

More articles from Life Sciences:

nachricht Less animal experiments on the horizon: Multi-organ chip awarded
19.10.2018 | Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS

nachricht RUDN chemist tested a new nanocatalyst for obtaining hydrogen
18.10.2018 | RUDN University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Goodbye, silicon? On the way to new electronic materials with metal-organic networks

Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz (Germany) together with scientists from Dresden, Leipzig, Sofia (Bulgaria) and Madrid (Spain) have now developed and characterized a novel, metal-organic material which displays electrical properties mimicking those of highly crystalline silicon. The material which can easily be fabricated at room temperature could serve as a replacement for expensive conventional inorganic materials used in optoelectronics.

Silicon, a so called semiconductor, is currently widely employed for the development of components such as solar cells, LEDs or computer chips. High purity...

Im Focus: Storage & Transport of highly volatile Gases made safer & cheaper by the use of “Kinetic Trapping"

Augsburg chemists present a new technology for compressing, storing and transporting highly volatile gases in porous frameworks/New prospects for gas-powered vehicles

Storage of highly volatile gases has always been a major technological challenge, not least for use in the automotive sector, for, for example, methane or...

Im Focus: Disrupting crystalline order to restore superfluidity

When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition, and countless others that occur in nature, typically takes place at the same fixed conditions, such as the freezing point, one can ask how it can be influenced in a controlled way.

We are all familiar with such control of the freezing transition, as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold...

Im Focus: Micro energy harvesters for the Internet of Things

Fraunhofer IWS Dresden scientists print electronic layers with polymer ink

Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed...

Im Focus: Dynamik einzelner Proteine

Neue Messmethode erlaubt es Forschenden, die Bewegung von Molekülen lange und genau zu verfolgen

Das Zusammenspiel aus Struktur und Dynamik bestimmt die Funktion von Proteinen, den molekularen Werkzeugen der Zelle. Durch Fortschritte in der...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Conference to pave the way for new therapies

17.10.2018 | Event News

Berlin5GWeek: Private industrial networks and temporary 5G connectivity islands

16.10.2018 | Event News

5th International Conference on Cellular Materials (CellMAT), Scientific Programme online

02.10.2018 | Event News

 
Latest News

Mineral discoveries in the Galapagos Islands pose a puzzle as to their formation and origin

19.10.2018 | Earth Sciences

Less animal experiments on the horizon: Multi-organ chip awarded

19.10.2018 | Life Sciences

New method uses just a drop of blood to monitor lung cancer treatment

19.10.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>