Features | Partner Sites | Information | LinkXpress
Sign In
GLOBETECH PUBLISHING
GLOBETECH PUBLISHING
JIB

Cryo-Electron Microscope Study Follows Changes in Dengue Fever Virus Morphology

By BiotechDaily International staff writers
Posted on 25 Apr 2013
A recent paper detailed a cryo-electron microscope study that revealed morphological changes that occur when the virus that causes dengue fever is warmed to human body temperature.

Dengue fever is an acute infectious disease caused by four closely related viruses and transmitted by the bite of the female Aedes mosquito. The disease, which has no specific treatment, occurs in both epidemic and sporadic form in warm climates. The classic symptoms, following an incubation period of five to eight days, are high fever, chills, severe headache, pain in the joints, pain behind the eyes, rash, sweating, and prostration, but infected persons may experience milder symptoms. Symptoms subside in two to four days, but after a remission lasting from a few hours to two days there is another rise in temperature, and a generalized rash appears. Dengue hemorrhagic fever, a severe form of the disease, can cause hemorrhage, shock, and encephalitis. It occurs when a person who has acquired immunity to one of the viruses that cause dengue fever is infected by a different dengue virus; antibodies to the first dengue infection apparently work to aid the second virus. It is a leading cause of death among children in Southeast Asia and in recent years has become increasingly prevalent in tropical America.

Investigators at Purdue University (West Lafayette, IN, USA) used a cryo-electron microscope to examine changes in morphology of the dengue virus as it warmed from 28 °C (the temperature found in mosquito or tick vectors) to the human body temperature of 37 °C. Cryo-electron microscopy allows the observation of specimens that have not been stained or fixed in any way, showing them in their native environment while integrating multiple images to form a three-dimensional model of the sample.

The investigators reported in the April 8, 2013, online edition of the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS) that at room temperature the virus had a smooth surface with a diameter of about 50 nanometers and little exposed membrane, while at human body temperature the virions had a bumpy appearance with a diameter of nearly 55 nanometers and some exposed membrane. The bumpy structure at 37 °C was similar to the previously predicted structure of an intermediate between the smooth form seen at lower temperatures and the mature form of the virus seen at the time of host cell invasion.

"The bumpy form of the virus would be the form present in humans, so the optimal dengue virus vaccines should induce antibodies that preferentially recognize epitopes exposed in that form," said senior author Dr. Michael G. Rossmann, professor of biological sciences at Purdue University.

Related Links:
Purdue University




comments powered by Disqus

Channels

Drug Discovery

view channel
Image: Synthetic ion transporters can induce apoptosis by facilitating chloride anion transport into cells (Photo courtesy of the University of Texas, Austin).

Experimental Drug Kills Cancer Cells by Interfering with Their Ion Transport Mechanism

An experimental anticancer drug induces cells to enter a molecular pathway leading to apoptosis by skewing their ion transport systems to greatly favor the influx of chloride anions. To promote development... Read more

Therapeutics

view channel
Image: Liver cells regenerated in mice treated with a new drug (right) compared with a control group (center) after partial liver removal. Healthy liver cells are shown at left (Photo courtesy of Marshall et al, 2014, the Journal of Experimental Medicine).

New Drug Triggers Liver Regeneration After Surgery

Investigators have revealed that an innovative complement inhibitor decreases complement-mediated liver cell death, and actually stimulates postsurgery liver regrowth in mice. Liver cancer often results... Read more

Lab Technologies

view channel

White-Matter Deficits Found in Codeine-Containing Cough Syrup Users

A magnetic resonance imaging (MRI) study of chronic users of codeine-containing cough syrups (CCS) has found deficits in specific regions of brain white matter and linked these changes with increased impulsivity in codeine-containing cough syrup users. These findings were consistent with findings from earlier research of... Read more

Business

view channel

Partnership Established to Decode Bowel Disease

23andMe (Mountain View, CA,USA), a personal genetics company, is collaborating with Pfizer, Inc. (New York, NY, USA), in which the companies will seek to enroll 10,000 people with inflammatory bowel disease (IBD) in a research project designed to explore the genetic factors associated with the onset, progression, severity,... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.