Insulin-like peptide DILP6 regulates juvenile hormone and dopamine metabolism in Drosophila females.

Insulin-like peptide DILP6 is a component of the insulin/insulin-like growth factor signalling pathway of Drosophila. Juvenile hormone (JH) and dopamine (DA) are involved in the stress response and in the control of reproduction. In this study, we investigate whether DILP6 regulates the JH and DA levels by studying the effect of a strong hypomorphic mutation dilp641 on JH and DA metabolism in D. melanogaster females. We show that DILP6 regulates JH and DA metabolism: the mutation dilp641 results in a reduction in JH-hydrolysing activity and an increase in the activities of DA synthesis enzymes (alkaline phosphatase (ALP) and tyrosine hydroxylase (TH)). In the mutant females, we also found increased fecundity in addition to the intensity of the response (stress reactivity) of ALP and TH to heat stress. As we showed previously, this suggests an increased level of JH synthesis. We confirm this suggestion by treating the mutant females with the JH inhibitor, precocene, which restors the activity and stress reactivity of ALP and TH as well as fecundity to levels similar to those in the control flies. The data suggest a feedback system in the interaction between JH and DILP6 in which DILP6 negatively regulates the JH titre via an increase in the hormone degradation and a decrease in its synthesis.

Detection of Mutations in Mitochondrial DNA by Droplet Digital PCR.

Mutations in mitochondrial DNA (mtDNA) may result in various pathological processes. Detection of mutant mtDNAs is a problem for diagnostic practice that is complicated by heteroplasmy - a phenomenon of the inferring presence of at least two allelic variants of the mitochondrial genome. Also, the level of heteroplasmy largely determines the profile and severity of clinical manifestations. Here we discuss detection of mutations in heteroplasmic mtDNA using up-to-date methods that have not yet been introduced as routine clinical assays. These methods can be used for detecting mutations in mtDNA to verify diagnosis of "mitochondrial disease", studying dynamics of mutant mtDNA in body tissues of patients, as well as investigating structural features of mtDNAs. Original data on allele-specific discrimination of m.11778G>A mutation by droplet digital PCR are presented, which demonstrate an opportunity for simultaneous detection and quantitative assessment of mutations in mtDNAs.