Features | Partner Sites | Information | LinkXpress
Sign In
GLOBETECH PUBLISHING LLC
GLOBETECH PUBLISHING LLC
GLOBETECH MEDIA

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




Channels

Drug Discovery

view channel
Image: Star-like glial cells in red surround alpha-beta plaques in the cortex of a mouse with a model of Alzheimer\'s disease (Photo courtesy of Strittmatter laboratory/Yale University).

Experimental Cancer Drug Reverses Symptoms in Mouse Model of Alzheimer's Disease

An experimental, but clinically disappointing drug for treatment of cancer has been found to be extremely effective in reversing the symptoms of Alzheimer's disease (AD) in a mouse model.... Read more

Biochemistry

view channel
Image:  Model depiction of a novel cellular mechanism by which regulation of cryptochromes Cry1 and Cry2 enables coordination of a protective transcriptional response to DNA damage caused by genotoxic stress (Photo courtesy of the journal eLife, March 2015, Papp SJ, Huber AL, et al.).

Two Proteins Critical for Circadian Cycles Protect Cells from Mutations

Scientists have discovered that two proteins critical for maintaining healthy day-night cycles also have an unexpected role in DNA repair and protecting cells against genetic mutations that could lead... Read more

Business

view channel

NanoString and MD Anderson Collaborate on Development of Novel Multi-Omic Expression Profiling Assays for Cancer

The University of Texas MD Anderson Cancer Center (Houston, TX, USA) and NanoString Technologies, Inc. (Seattle, WA, USA) will partner on development of a revolutionary new type of assay—simultaneously profiling gene and protein expression, initially aiming to discover and validate biomarker signatures for immuno-oncology... Read more
 
Copyright © 2000-2015 Globetech Media. All rights reserved.