Researchers at the Johns Hopkins Bloomberg School of Public Health have identified a gene in the Anopheles gambiae mosquito’s DNA that is central to the insect’s ability to defend against infectious pathogens, including Plasmodium, the parasite that causes malaria in humans. Potentially, a mosquito with an enhanced capacity to recognize and kill Plasmodium would be unable to transmit malaria. The researchers' findings appear in the June 20, 2006, edition of the journal PLoS Biology.
Insects do not have antibodies, which are essential for pathogen recognition in humans. Instead, insects rely on a limited number of genes coding for adhesive proteins (pattern-recognition receptors) that can adhere to molecular patterns on a pathogen’s surface.
“Each pathogen has its own unique combination of surface patterns. The immune systems of the mosquito and other insects primarily rely on recognizing the pattern of a specific pathogen to activate an immune response that kills the invader,” explained George Dimopoulos, PhD, senior author of the study and assistant professor in the Bloomberg School’s Malaria Research Institute. The AgDscam gene—short for Anopheles gambiae Down syndrome cell adhesion molecule gene—is an essential factor of the mosquito’s immune system and can produce thousands of receptors with different pathogen-binding specificities. AgDscam appears to be capable of recognizing a broad range of different pathogens, and can thereby carry out a function for which a large number of genes would have been needed. Studies previously conducted by other researchers identified an immunity-related function of the Dscam gene in fruit flies.
The researchers found that when the AgDscam gene was deactivated, or “silenced”, the mosquitoes died at a greater rate from bacterial infections. They also found that the numbers of Plasmodium increased 65 percent in the gut of mosquitoes with the silenced gene. The findings suggest that better knowledge of how the AgDscam gene is involved in killing Plasmodium could be used to develop novel ways to control malaria.
The AgDscam gene has 101 protein-coding regions, called exons, that can be spliced together in different combinations to produce over 31,000 possible splice-forms that function as receptors. When the mosquitoes were exposed to different pathogens such as bacteria, fungi and parasites, the AgDscam gene produced an array of different splice-forms with different interaction properties. When the researchers cut AgDscam protein levels in half, they could link AgDscam’s function with the immune system, as the mosquitoes became less resistant to infection. The results showed that infected mosquitoes produced AgDscam splice-forms (receptors) that were better in recognizing—and defending against—the invading pathogen.
“AgDscam is in a way similar to antibodies; different combinations of immunoglobulin domains, which are coded by spliced exons, are used to produce a broad range of receptors. Now we need to learn more about AgDscam’s association with the malaria parasite. A mosquito with an enhanced capacity to recognize and kill Plasmodium would not transmit malaria,” said Dimopoulos.
In a previous study published in the June 8, 2006, edition of PLoS Pathogens, the Hopkins researchers determined that mosquitoes employ the same immune factors to fight off bacterial pathogens as they do to kill malaria-causing Plasmodium parasites.
“AgDscam, a hyper variable immunoglobulin domain containing receptor of the Anopheles gambiae innate immune system” was written by Yuemei Dong, Harry Taylor and George Dimopoulos. Dong and Dimopoulos are with the W. Harry Feinstone Department of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health. Taylor is currently with Meharry Medical College.
The study was supported by grants from the National Institute of Allergy and Infectious Disease, the World Health Organization Training in Tropical Diseases program, the Ellison Medical Foundation and the Johns Hopkins Malaria Research Institute.
Public Affairs media contacts for the Johns Hopkins Bloomberg School of Public Health: Tim Parsons or Kenna Lowe at 410-955-6878 or email@example.com.
Tim Parsons | EurekAlert!
‘Farming’ bacteria to boost growth in the oceans
24.10.2016 | Max-Planck-Institut für marine Mikrobiologie
Calcium Induces Chronic Lung Infections
24.10.2016 | Universität Basel
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
24.10.2016 | Earth Sciences
24.10.2016 | Life Sciences
24.10.2016 | Physics and Astronomy