Navigation Links
African parasite makes component of fat differently from all other organisms

Studying the parasite that causes African sleeping sickness, scientists at Johns Hopkins have discovered a previously unknown way of making fatty acids, a component of fat and the outer layer of all cells. The find unveils more about the biology of this hard-to-kill parasite and could lead to a target for designing new drugs to fight the illness that infects a half-million people and kills 50,000 a year worldwide.

Results of the study, in the Aug. 25 issue of Cell, "show that this is a completely new biochemical pathway for making fatty acids," says Soo Hee Lee, Ph.D., a postdoctoral fellow in the Department of Biological Chemistry at the Institute for Basic Biomedical Sciences at Hopkins. "It may be that the enzymes in the pathway could be good targets for designing drugs to treat sleeping sickness."

The single-celled trypanosome that causes African sleeping sickness, transmitted between humans and animals by bloodsucking tsetse flies, goes through several different stages in its life cycle. One such form is harbored by the insect and the other multiplies in a host's bloodstream.

There, the parasite avoids detection by the human immune system by replacing each of the 10 million proteins on its outer layer - known as the cell membrane - with different proteins that are not recognized by immune cells. These proteins are attached to the cell membrane by an anchor composed in part of a fatty acid only 14 units long - dubbed myristate -- whereas typically, in other organisms, these types of anchors contain longer fatty acids, generally 16 or 18 units long.

"For many years we thought the parasite had to get the myristate from its human host because we never could see any evidence that it could make the fatty acid itself," says Paul Englund, Ph.D., a professor of biological chemistry in the Institute of Basic Biomedical Sciences at Hopkins. "Several years ago we found that it does actually make myristate as well as other fatty acids, a nd now we found that it uses a biochemical pathway we never knew to look for."

They learned about this new fatty acid-making pathway by hunting the trypanosome genome for stretches of DNA known to be involved in fatty acid synthesis in other organisms, like animals and plants.

The researchers reasoned that knocking out the fatty acid-making genes would prevent the parasite from making myristate and other fatty acids.

But when one member of the research team, Jennifer Stephens, knocked out a single gene in the trypanosome known to make fatty acids in other organisms, there was no change in the parasite's ability to make myristate. Surprised, the researchers then examined the trypanosome genome more carefully and discovered enzymes that in other organisms are known to increase the size of a fatty acid molecule - dubbed elongases, for making fatty acids longer - but never have been shown to actually make a new fatty acid molecule.

Lee knocked out these elongases to see if the parasite might have difficulty making fatty acids. To the researchers' surprise, the parasites lacking elongases were unable to make the 14-unit myristate or other fatty acids.

"A novel feature of the elongase pathway is that it contains four different enzymes that take turns in elongating fatty acids," says Lee. "This modular pathway allows the parasite to control the size of the fatty acids it makes."

"It turns out that trypanosomes use an entirely unique mechanism of making fatty acids. No other organism ever studied uses elongases to make them," says Englund, suggesting that attacking biochemical pathways that make fatty acids could be a way to treat sleeping sickness. According to the researchers, the research community is extremely interested in developing drugs that target bacterial enzymes involved in fatty acid synthesis. An example of one is called isoniazid, which currently is used to treat tuberculosis.

"Trypanosomes c ause significant health problems in remote areas of Africa with poor health care," says Englund. "There is tremendous need for new drugs to cure these diseases."
'"/>

Source:Johns Hopkins Medical Institutions


Related biology news :

1. New push for public health, AIDS spending at African Union summit
2. South African Tribunal Asks For Damages Estimates in GSK AIDS Drug Case
3. Six million Africans face famine because of locusts, drought
4. Fungus-farming termites descend from an African rain forest Eve
5. Poaching, logging, and outbreaks of Ebola threaten central African gorillas and chimpanzees
6. Compound might defeat African sleeping sickness, clinical trial beginning this month
7. Crisis in African fish supplies looms, experts warn Africa leaders
8. New partnership to clear landmines for African Elephants
9. US/African project deciphers deadly parasite genome
10. Tropical Atlantic cooling and African deforestation correlate to drought, report scientists
11. Newly identified mechanism helps explain why people of African descent are more vulnerable to TB

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/18/2016)... LONDON , March 18, 2016 ... Established Suppliers of Biometrics, ICT, Manned & Unmanned Vehicles, Physical ... & security companies in the border security market and ... and Europe has led ... your companies improved success. --> defence & ...
(Date:3/14/2016)... March 14, 2016 http://www.apimages.com ... --> - Renvoi : image disponible via ... --> --> DERMALOG, le ... de nouveaux lecteurs d,empreintes digitales pour l,enregistrement des ... sera utilisé pour produire des cartes d,identité aux ...
(Date:3/9/2016)... 2016 This BCC Research report provides an ... RNA Sequencing (RNA Seq) market for the years 2015, ... and reagents, data analysis, and services. Use ... RNA-Sequencing market such as RNA-Sequencing tools and reagents, RNA-Sequencing ... affecting each segment and forecast their market growth, future ...
Breaking Biology News(10 mins):
(Date:5/25/2016)... ... May 25, 2016 , ... Lajollacooks4u has become a rising hotspot for specialized ... of its top attractions. Fortune 500 companies, such as Illumina, Hewlett-Packard, Qualcomm and ... intimate team-building experience. , Each event kicks off with an olive oil and salt-tasting ...
(Date:5/25/2016)... ... May 25, 2016 , ... The Ankle Plating System 3 ... to address fractures of the distal tibia and fibula. This system marks Acumed's ... System 3 is composed of seven plate families that span the lateral, medial, ...
(Date:5/25/2016)... ... 2016 , ... The American Medical Informatics Association (AMIA) responded ... Coordinator for Health IT (ONC) outlining a measurement approach to interoperability that focuses ... and where it was needed. The organization of health informatics professionals said a ...
(Date:5/25/2016)... UTAH. (PRWEB) , ... May 25, 2016 , ... WEDI, ... healthcare information exchange, today announced that Charles W. Stellar has been named by the ... interim CEO since January 2016. As an executive leader with more than 35 years ...
Breaking Biology Technology: