Dietary Restriction in Drosophila: Delayed Aging or Experimental Artefact?

Lifespan can be extended by reduction of dietary intake. This practice is referred to as dietary restriction (DR), and extension of lifespan by DR is evolutionarily conserved in taxonomically diverse organisms including yeast, invertebrates, and mammals. Although these two often-stated facts carry the implication that the mechanisms of DR are also evolutionarily conserved, extension of lifespan could be a case of evolutionary convergence, with different underlying mechanisms in different taxa. Furthermore, extension of lifespan by different methods of DR in the same organism may operate through different mechanisms. These topics remain unresolved because of the very fact that the mechanisms of DR are unknown. Given these uncertainties, it is essential that work on the mechanisms of DR is not clouded by imprecise descriptions of methods or by technical problems. Here we review the recent literature on DR in Drosophila to point out some methodological issues that can obscure mechanistic interpretations. We also indicate some experiments that could be performed to determine if DR in Drosophila operates through similar mechanisms to the process in rodents

Detrimental effects of RNAi: a cautionary note on its use in Drosophila ageing studies

RNA interference (RNAi) provides an important tool for gene function discovery. It has been widely exploited in Caenorhabditis elegans ageing research because it does not appear to have any non-specific effects on ageing-related traits in that model organism. We show here that ubiquitous, adult-onset activation of the RNAi machinery, achieved by expressing a double stranded RNA targeting GFP or lacZ for degradation, or by increasing expression of Dicer substantially reduces lifespan in Drosophila melanogaster. Induction of GFPRNAi construct also alters the response of lifespan to nutrition, exacerbating the lifespan-shortening effects of food containing a high quantity of yeast. Our study indicates that activation of the RNAi machinery may have sequence-independent side-effects on lifespan, and that caution needs to be exercised when employing ubiquitous RNAi in Drosophila ageing studies. However, we also show that RNAi restricted to certain tissues may not be detrimental to lifespan

Evolutionary conservation of regulated longevity assurance mechanisms

Short abstract: A multi-level cross-species comparative analysis of gene-expression changes accompanying increased longevity in mutant nematodes, fruit flies and mice with reduced insulin/IGF-1 signaling revealed candidate conserved mechanisms

County and Demographic Differences in Drug Arrests and Controlled Substance Use in Maine

. Introduction: The Diversion Alert Program (DAP) was established to curb misuse of drugs and help identify people who may need treatment for substance use disorder (SUD). Law enforcement compiled arrest data into a database accessible by health care providers. Our objectives were to identify regional and demographic differences in drug use and misuse in Maine. Methods: All arrests (N = 11 234) reported to the DAP from 2013 to 2018 were examined by county and arrestee demographics, and classified into families (opioids, stimulants, sedatives). The Drug Enforcement Administration’s Automation of Reports and Consolidated Orders System (ARCOS) tracks the distribution of controlled pharmaceuticals (Schedule II-III). Opioids were converted to oral morphine milligram equivalents (MMEs). County and zip-code maps were constructed. Results: The most arrests per capita occurred in Androscoggin, Knox, and Cumberland Counties. Opioids were the most common drug class in arrests in all counties except Aroostook County, where stimulants were most common. Medical distribution of opioids varied. Although buprenorphine doubled, many prescription opioids (eg, hydrocodone, fentanyl, oxymorphone) exhibited large (\u3e 50%) reductions in distribution. Methadone was the predominant opioid statewide (56.4% of total MMEs), although there were sizable differences between regions (Presque Isle = 8.6%, Bangor = 78.9%). Amphetamine distribution increased by 67.9%. Discussion: The DAP, a unique pharmacoepidemiological resource, revealed a 6-fold difference in drug arrests by county. Regional differences in methadone may be due to heterogeneities in methadone clinic distribution. Conclusions: The decrease in most prescription opioids, but increase in prescription stimulants, may warrant continued monitoring to improve public health

Synergistic Degradation Mechanism in Single Crystal Ni-Rich NMC//Graphite Cells

Acknowledgments We acknowledge Diamond Light Source for time on beamline I09 under Proposals SI30201-1 and SI30201-2. This work is supported by the Faraday Institution under Grants FIRG044, FIRG024, and FIRG060.Peer reviewedPublisher PD

Restriction of essential amino acids dictates the systemic metabolic response to dietary protein dilution

Dietary protein dilution, where protein is reduced and replaced by other nutrient sources without caloric restriction, promotes metabolic health via the hepatokine Fgf21. Here, the authors show that essential amino acids threonine and tryptophan are necessary and sufficient to induce these effects

Influence of Polymorphism on the Electronic Structure of Ga2O3

The search for new wide band gap materials is intensifying to satisfy the need for more advanced and energy efficient power electronic devices. Ga$_2$O$_3$ has emerged as an alternative to SiC and GaN, sparking a renewed interest in its fundamental properties beyond the main $\beta$-phase. Here, three polymorphs of Ga$_2$O$_3$, $\alpha$, $\beta$ and $\varepsilon$, are investigated using X-ray diffraction, X-ray photoelectron and absorption spectroscopy, and ab initio theoretical approaches to gain insights into their structure - electronic structure relationships. Valence and conduction electronic structure as well as semi-core and core states are probed, providing a complete picture of the influence of local coordination environments on the electronic structure. State-of-the-art electronic structure theory, including all-electron density functional theory and many-body perturbation theory, provide detailed understanding of the spectroscopic results. The calculated spectra provide very accurate descriptions of all experimental spectra and additionally illuminate the origin of observed spectral features. This work provides a strong basis for the exploration of the Ga$_2$O$_3$ polymorphs as materials at the heart of future electronic device generations.Comment: Updated manuscript version after peer revie

The S4–S5 Linker Acts as a Signal Integrator for hERG K+ Channel Activation and Deactivation Gating

Human ether-à-go-go-related gene (hERG) K+ channels have unusual gating kinetics. Characterised by slow activation/deactivation but rapid inactivation/recovery from inactivation, the unique gating kinetics underlie the central role hERG channels play in cardiac repolarisation. The slow activation and deactivation kinetics are regulated in part by the S4–S5 linker, which couples movement of the voltage sensor domain to opening of the activation gate at the distal end of the inner helix of the pore domain. It has also been suggested that cytosolic domains may interact with the S4–S5 linker to regulate activation and deactivation kinetics. Here, we show that the solution structure of a peptide corresponding to the S4–S5 linker of hERG contains an amphipathic helix. The effects of mutations at the majority of residues in the S4–S5 linker of hERG were consistent with the previously identified role in coupling voltage sensor movement to the activation gate. However, mutations to Ser543, Tyr545, Gly546 and Ala548 had more complex phenotypes indicating that these residues are involved in additional interactions. We propose a model in which the S4–S5 linker, in addition to coupling VSD movement to the activation gate, also contributes to interactions that stabilise the closed state and a separate set of interactions that stabilise the open state. The S4–S5 linker therefore acts as a signal integrator and plays a crucial role in the slow deactivation kinetics of the channel