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Deer Tick Virus
Deer tick virus (DTV) is a virus in the genus ''Flavivirus'' spread via ticks that causes encephalitis. Taxonomy DTV closely resembles Powassan virus (to which it has 84% nucleotide sequence identity and 94% amino acid sequence identity). Due to their close similarities, DTV is also called Powassan virus lineage II. The DTV lineage is presumed to be maintained between ''Ixodes scapularis'', or deer ticks, and the white-footed mouse (''Peromyscus leucopus''). Epidemiology DTV has a strong prevalence in the northeastern and north central part of the United States, although little to no human infections have been reported. Only about 1 to 3% of ''I. scapularis'' ticks in the northern United States are possibly infected with DTV. This infers that the virus is not seriously pathogenic or it does not easily infect humans. Human incidence might be severely underestimated. History In 1997, it was isolated from ''I. scapularis'' ticks collected in Massachusetts and Connecticut. A fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feulgen Stain
Feulgen stain is a staining technique discovered by Robert Feulgen and used in histology to identify chromosomal material or DNA in cell specimens. It is darkly stained. It depends on acid hydrolysis of DNA, therefore fixating agents using strong acids should be avoided. The specimen is subjected to warm (60 °C) hydrochloric acid, then to Schiff reagent. In the past, a sulfite rinse followed, but this is now considered unnecessary. Optionally, the sample can be counterstained with Light Green SF yellowish. Finally, it is dehydrated with ethanol, cleared with xylene, and mounted in a resinous medium. DNA should be stained red. The background, if counterstained, is green. The Feulgen reaction is a semi-quantitative technique. If the only aldehydes remaining in the cell are those produced from the hydrolysis of DNA, then the technique is quantitative for DNA. It is possible to use an instrument known as a microdensitometer or microspectrophotometer to actually measure the intensit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |