Microglia
Research has discovered dystrophic (defective development) human microglia. "These cells are characterized by abnormalities in their cytoplasmic structure, such as deramified, atrophic, fragmented or unusually tortuous processes, frequently bearing spheroidal or bulbous swellings." The incidence of dystrophic microglia increases with aging. Microglial degeneration and death have been reported in research on Prion disease, Schizophrenia and Alzheimer's disease, indicating that microglial deterioration might be involved in neurodegenerative diseases. A complication of this theory is the fact that it is difficult to distinguish between "activated" and "dystrophic" microglia in the human brain.
Spot 42 RNA
Spot42 was first described in 1973 as an unstable RNA species of 109 nucleotides in "Escherichia coli". It was discovered by polyacrylamide gel electrophoresis and 2-D fingerprinting in an attempt to study the accumulation of small RNAs in "E. coli" during amino acid starvation. In these experiments the electrophoretic mobility of Spot42 was similar to that of 5S rRNA. In 1979 Spot42 was found to accumulate under growth in the presence of glucose (i.e., when adenosine 3′,5′-cyclic monophosphate (cAMP) is low). During growth with a non-glucose carbon source (i.e., when cAMP concentrations are high) the Spot42 concentrations were found to be significantly lower.