Genomic, Evolutionary and Functional Analyses of Diapause in Drosophila Melanogaster

Understanding the genetic basis of adaptation has been and remains to be one major goal of ecological and evolutionary genetics. The variation in diapause propensity in the model organism Drosophila melanogaster represents different life-history strategies underlying adaptation to regular and widespread environmental heterogeneity, thus provides an ideal model to study the genetic control of ecologically important complex phenotype. This work employs global genomic and transcriptomic approaches to identify genetic polymorphisms co-segregating with diapause propensity, as well as genes that are differentially regulated at the transcriptional level as a function of the diapause phenotype. I show that genetic polymorphisms co-segregating with diapause propensity are found throughout all major chromosomes, demonstrating that diapause is a multi-genic trait. I show that diapause in D. melanogaster is an actively regulated phenotype at the transcriptional level, suggesting that diapause is not a simple physiological or reproductive quiescence. I also demonstrate that genetic polymorphisms co-segregating with diapause propensity, as well as genes differentially expressed as a function of diapause are enriched for clinally varying and seasonal oscillating SNPs, supporting the hypothesis that natural variation in diapause propensity underlies adaptation to spatially and temporally varying selective pressures. In addition to global genomic and transcriptomic screens, I also performed functional analysis of one candidate polymorphism on the gene Crystalllin, which represents an intersection of multiple global screens related to seasonal adaptation. I show that this polymorphism affects patterns of gene expression and a subset of fitness-related phenotypes including diapause, in an environment-specific manner. Taken together, this work provide a holistic view of the genetic basis of a complex trait underlying climatic adaptation in wild populations of D. melanogaster, linking genetic polymorphism, gene regulation, organismal phenotype, population dynamics and environmental parameters

Global application of an unoccupied aerial vehicle photogrammetry protocol for predicting aboveground biomass in non‐forest ecosystems

P. 1-15Non-forest ecosystems, dominated by shrubs, grasses and herbaceous plants, provide ecosystem services including carbon sequestration and forage for grazing, and are highly sensitive to climatic changes. Yet these ecosystems are poorly represented in remotely sensed biomass products and are undersampled by in situ monitoring. Current global change threats emphasize the need for new tools to capture biomass change in non-forest ecosystems at appropriate scales. Here we developed and deployed a new protocol for photogrammetric height using unoccupied aerial vehicle (UAV) images to test its capability for delivering standardized measurements of biomass across a globally distributed field experiment. We assessed whether canopy height inferred from UAV photogrammetry allows the prediction of aboveground biomass (AGB) across low-stature plant species by conducting 38 photogrammetric surveys over 741 harvested plots to sample 50 species. We found mean canopy height was strongly predictive of AGB across species, with a median adjusted R2 of 0.87 (ranging from 0.46 to 0.99) and median prediction error from leave-one-out cross-validation of 3.9%. Biomass per-unit-of-height was similar within but different among, plant functional types. We found that photogrammetric reconstructions of canopy height were sensitive to wind speed but not sun elevation during surveys. We demonstrated that our photogrammetric approach produced generalizable measurements across growth forms and environmental settings and yielded accuracies as good as those obtained from in situ approaches. We demonstrate that using a standardized approach for UAV photogrammetry can deliver accurate AGB estimates across a wide range of dynamic and heterogeneous ecosystems. Many academic and land management institutions have the technical capacity to deploy these approaches over extents of 1–10 ha−1. Photogrammetric approaches could provide much-needed information required to calibrate and validate the vegetation models and satellite-derived biomass products that are essential to understand vulnerable and understudied non-forested ecosystems around the globe.S

The LIMD1 protein bridges an association between the prolyl hydroxylases and VHL to repress HIF-1 activity

Note: Supplementary Information is available on the Nature Cell Biology websitee. K.S.B. is supported by a Biotechnology and Biological Sciences Research Council Doctorate Training Award. V.J. and D.E.F. were supported by funding from the Biotechnology and Biological Sciences Research Council (BB/F006470/1 and BB/I007571/1) awarded to T.V.S

Signaling and stress: the redox landscape in nos2 biology

Nitric oxide (NO) has a highly diverse range of biological functions from physiological signaling and maintenance of homeostasis to serving as an effector molecule in the immune system. Many of the dichotomous effects of NO and derivative reactive nitrogen species (RNS) can be explained by invoking precise interactions with different targets as a result of concentration and temporal constraints. Endogenous concentrations of NO span five orders of magnitude, with levels near the high picomolar range typically occurring in short bursts as compared to sustained production of low micromolar levels of NO during immune response. This article provides an overview of the redox landscape as it relates to increasing NO concentrations, which incrementally govern physiological signaling, nitrosative signaling and nitrosative stress-related signaling. Physiological signaling by NO primarily occurs upon interaction with the heme protein soluble guanylyl cyclase. As NO concentrations rise, interactions with nonheme iron complexes as well as indirect modification of thiols can stimulate additional signaling processes. At the highest levels of NO, production of a broader range of RNS, which subsequently interact with more diverse targets, can lead to chemical stress. However, even under such conditions, there is evidence that stress-related signaling mechanisms are triggered to protect cells or even resolve the stress. This review therefore also addresses the fundamental reactions and kinetics that initiate signaling through NO-dependent pathways, including the chemistry of RNS and their molecular targets