Stress-induced microRNA changes
February 27, 2014 | James Kohl
on 2/27/14 at 3:25 pm I submitted this excerpt for posting to the ISHE’s human ethology yahoo group moderated by Jay R. Feierman.
Press conference presenter Karen Scott, a postdoctoral fellow in the laboratory of John Cryan at University College Cork in Ireland, is also interested in stress sensitivity and stress resistance. Scott described her work tracking molecular changes following a stressful event. Scott measured changes in microRNA (miRNA) levels in the hippocampus of two strains of mice (stress-sensitive BALB/c and stress-resistant C57BL/6J) following 10 days of exposure to the social defeat test. miRNA are tiny snippets of messenger RNA that block or degrade other RNA messages. Following stress, expression of miR-16 — which has been implicated in the development of depression — was elevated in BALB/c mice. Conversely, C57BL/6J showed higher levels of miR-34c. “These studies show that there is a correlation between behavioral and physiological responses to social defeat,” Scott said. However, she noted, future studies will need to explore whether manipulating miRNAs in the brain can alter symptoms of depression. on 2/27/14 at 4:10 pm Feierman posted it to the group with other articles under the header: Inside Science: Scientists Consider New Ways to Diagnose, Treat Depression on 2/27/14 at 8:10 pm, I submitted this for posting the ISHE’s human ethology yahoo group moderated by Jay R. Feierman.
Diversity Down Below Andrew M. Sugden
Despite a surge of research efforts in recent years, the challenges faced by soil biologists remain daunting. Knowledge of even the basic elements of the biodiversity that is so visible above ground—in particular, species diversity and distribution—remains far more rudimentary where life below the soil surface is concerned. Soil fungi are a case in point. A key component of the soil ecosystem, its global species diversity, has tended to be estimated by various proxies. From a study of the fungi of boreal forest soils in Alaska, Taylor et al. suggest that previous estimates of fungal diversity, which hitherto hovered between 0.5 and 1.5 million, might need to be revised upward. Fungal DNA sequence data from their samples yielded just over 1000 discrete fungal taxa—many more than had been estimated from nonmolecular data. Within the soil, the fungal species communities were found to be highly structured and correlated with abiotic variables such as pH and soil horizon, and with the species composition of the understory plant community. The revealed fungus:plant ratio of 17:1, if reflected globally, would extrapolate to at least 6 million fungal species, suggesting in turn that 98% of fungi have yet to be described—a figure that remains to be corroborated by similarly detailed sampling across a range of other soil ecosystems. Ecol. Monogr. 84, 3 (2014).
Feierman is beginning to realize how the diversity down below is linked via conserved molecular mechanisms from microbes to man via microRNA changes. Of course he could claim that he found the “MicroRNAs Change after Stressful Events” on his own rather than admit he is continuing to thwart my efforts to inform the group . But, even if he lies about where the information is coming from, it has clearly become more important to know how the ecological variants of nutrient stress and social stress epigenetically effect ecological adaptations via microRNAs to prevent more confusion about the representations of “constraint-breaking” mutations. For example, while the epigenetic effects of nutrient stress and social stress can be used to explain species diversity in the context of the molecular epigenetics I have detailed, the overwhelming amount of species diversity below ground and above ground cannot be explained by “constraint-breaking” mutations. Besides, no experimental evidence suggests that constraint-breaking mutations have anything to do with species diversity. As we can surmise from the header “Ecology” in the editor’s choice above, unless ecological factors are considered, conclusions drawn from population genetics make no sense.