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https://www.readbyqxmd.com/read/28646164/regulation-of-drosophila-lifespan-by-bellwether-promoter-alleles
#1
Júlia Frankenberg Garcia, Mary Anna Carbone, Trudy F C Mackay, Robert R H Anholt
Longevity varies among individuals, but how natural genetic variation contributes to variation in lifespan is poorly understood. Drosophila melanogaster presents an advantageous model system to explore the genetic underpinnings of longevity, since its generation time is brief and both the genetic background and rearing environment can be precisely controlled. The bellwether (blw) gene encodes the α subunit of mitochondrial ATP synthase. Since metabolic rate may influence lifespan, we investigated whether alternative haplotypes in the blw promoter affect lifespan when expressed in a co-isogenic background...
June 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28645845/the-feature-weighted-receptive-field-an-interpretable-encoding-model-for-complex-feature-spaces
#2
REVIEW
Ghislain St-Yves, Thomas Naselaris
We introduce the feature-weighted receptive field (fwRF), an encoding model designed to balance expressiveness, interpretability and scalability. The fwRFis organized around the notion of a feature map-a transformation of visual stimuli into visual features that preserves the topology of visual space (but not necessarily the native resolution of the stimulus). The key assumption of the fwRFmodel is that activity in each voxel encodes variation in a spatially localized region across multiple feature maps. This region is fixed for all feature maps; however, the contribution of each feature map to voxel activity is weighted...
June 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28645710/impact-of-upstream-river-inputs-and-reservoir-operation-on-phosphorus-fractions-in-water-particulate-phases-in-the-three-gorges-reservoir
#3
Chaonan Han, Binghui Zheng, Yanwen Qin, Yingqun Ma, Chenchen Yang, Zhichao Liu, Wei Cao, Minghui Chi
The impoundment of the Three Gorges Reservoir (TGR) has changed water-sand transport regime, with inevitable effects on phosphorus transport behavior in the TGR. In this study, we measured phosphorus fractions in water and suspended particles transported from upstream rivers of the TGR (the Yangtze River, the Jialing River and the Wu River) to reservoir inner region over the full operation schedule of the TGR. The aim was to determine how phosphorus fractions in water and particulate phases varied in response to natural hydrological processes and reservoir operations...
June 21, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28645641/homogenizing-bacterial-cell-factories-analysis-and-engineering-of-phenotypic-heterogeneity
#4
REVIEW
Dennis Binder, Thomas Drepper, Karl-Erich Jaeger, Frank Delvigne, Wolfgang Wiechert, Dietrich Kohlheyer, Alexander Grünberger
In natural habitats, microbes form multispecies communities that commonly face rapidly changing and highly competitive environments. Thus, phenotypic heterogeneity has evolved as an innate and important survival strategy to gain an overall fitness advantage over cohabiting competitors. However, in defined artificial environments such as monocultures in small- to large-scale bioreactors, cell-to-cell variations are presumed to cause reduced production yields as well as process instability. Hence, engineering microbial production toward phenotypic homogeneity is a highly promising approach for synthetic biology and bioprocess optimization...
June 20, 2017: Metabolic Engineering
https://www.readbyqxmd.com/read/28645630/evolution-of-cyclodextrin-nanosponges
#5
Fabrizio Caldera, Maria Tannous, Roberta Cavalli, Marco Zanetti, Francesco Trotta
Cyclodextrin-based nanosponges (CD-NSs) are insoluble, highly cross-linked 3D network polymers used in several scientific and technological fields, the main area of investigation concerns the pharmaceutical applications, in which CD-NSs have been mostly employed as drug delivery systems. CD-NSs can be generally grouped into four consecutive generations, taking into account their chemical composition and properties. The 1st generation of NSs are plain nanosponges, subdivided into four main types: urethane, carbonate, ester and ether NSs, depending on the chemical nature of the functional group connecting the CD to the cross-linker...
June 20, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28645163/variations-in-chloroplast-movement-and-chlorophyll-fluorescence-among-chloroplast-division-mutants-under-light-stress
#6
Siddhartha Dutta, Jeffrey A Cruz, Saif M Imran, Jin Chen, David M Kramer, Katherine W Osteryoung
Chloroplasts divide to maintain consistent size, shape, and number in leaf mesophyll cells. Altered expression of chloroplast division proteins in Arabidopsis results in abnormal chloroplast morphology. To better understand the influence of chloroplast morphology on chloroplast movement and photosynthesis, we compared the chloroplast photorelocation and photosynthetic responses of a series of Arabidopsis chloroplast division mutants with a wide variety of chloroplast phenotypes. Chloroplast movement was monitored by red light reflectance imaging of whole plants under increasing intensities of white light...
June 22, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28644542/the-conservation-significance-of-natural-hybridisation-in-mediterranean-plants-from-a-case-study-on-cyclamen-primulaceae-to-a-general-perspective
#7
John D Thompson, Perrine Gauthier, Guillaume Papuga, Virginie Pons, Max Debussche, Emmanuele Farris
Hybridisation plays a prominent role in plant evolution due to its influence on genetic diversity, fitness and adaptive potential We identify a case of on-going hybrid evolution of floral phenotypes in disjunct populations of Cyclamen balearicum and C. repandum subsp. repandum on Corsica and Sardinia. Hybrid populations on the two islands contain similar patterns of variation in flower colour and size but are probably at different stages in the evolutionary process of hybridisation and differences in the frequency of floral types and flower size suggest hybrid vigour that may contribute to the dynamics and maintenance of hybrid forms...
June 23, 2017: Plant Biology
https://www.readbyqxmd.com/read/28644109/the-timing-of-gigantea-expression-during-day-night-cycles-varies-with-the-geographical-origin-of-arabidopsis-accessions
#8
Amaury de Montaigu, George Coupland
Latitudinal clines in circadian rhythms have consistently been described in various plant species, with the most recent examples appearing in soybean cultivars and in monkey flower natural populations. These latitudinal clines provide evidence that natural variation in circadian rhythms is adaptive, but it is still unclear what adaptive benefits this variation confers, particularly because circadian rhythms are not usually measured in day/night conditions that reflect those experienced by organisms in nature...
June 23, 2017: Plant Signaling & Behavior
https://www.readbyqxmd.com/read/28642972/does-contrast-between-eggshell-ground-and-spot-coloration-affect-egg-rejection
#9
Miri Dainson, Mark E Hauber, Analía V López, Tomáš Grim, Daniel Hanley
Obligate avian brood parasitic species impose the costs of incubating foreign eggs and raising young upon their unrelated hosts. The most common host defence is the rejection of parasitic eggs from the nest. Both egg colours and spot patterns influence egg rejection decisions in many host species, yet no studies have explicitly examined the role of variation in spot coloration. We studied the American robin Turdus migratorius, a blue-green unspotted egg-laying host of the brown-headed cowbird Molothrus ater, a brood parasite that lays non-mimetic spotted eggs...
August 2017: Die Naturwissenschaften
https://www.readbyqxmd.com/read/28642345/evolution-of-nonspectral-rhodopsin-function-at-high-altitudes
#10
Gianni M Castiglione, Frances E Hauser, Brian S Liao, Nathan K Lujan, Alexander Van Nynatten, James M Morrow, Ryan K Schott, Nihar Bhattacharyya, Sarah Z Dungan, Belinda S W Chang
High-altitude environments present a range of biochemical and physiological challenges for organisms through decreases in oxygen, pressure, and temperature relative to lowland habitats. Protein-level adaptations to hypoxic high-altitude conditions have been identified in multiple terrestrial endotherms; however, comparable adaptations in aquatic ectotherms, such as fishes, have not been as extensively characterized. In enzyme proteins, cold adaptation is attained through functional trade-offs between stability and activity, often mediated by substitutions outside the active site...
June 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28641544/post-mortem-redistribution-of-drugs-current-state-of-knowledge
#11
Caroline Sastre, Christophe Bartoli, Valerie Baillif-Couniou, Georges Leonetti, Anne-Laure Pelissier-Alicot
BACKGROUND: Drug concentrations obtained from post mortem samples do not necessarily reflect the concentrations at the time of death, and variations of concentration may be observed between different sites and/or different sampling times. These phenomena, collectively termed post mortem redistribution, concern numerous molecules (medications, drugs of abuse, gases, etc.) and can complicate the interpretation of toxicological analyses. METHODS: Literature review...
June 22, 2017: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/28641304/hyperemesis-gravidarum-a-review-of-recent-literature
#12
Viktoriya London, Stephanie Grube, David M Sherer, Ovadia Abulafia
BACKGROUND: In the United States, hyperemesis gravidarum is the most common cause of hospitalization during the first half of pregnancy and is second only to preterm labor for hospitalizations in pregnancy overall. In approximately 0.3-3% of pregnancies, hyperemesis gravidarum is prevalent and this percentage varies on account of different diagnostic criteria and ethnic variation in study populations. Despite extensive research in this field, the mechanism of the disease is largely unknown...
June 23, 2017: Pharmacology
https://www.readbyqxmd.com/read/28641183/size-partitioning-and-mixing-behavior-of-trace-metals-and-dissolved-organic-matter-in-a-south-china-estuary
#13
Wenhao Wang, Min Chen, Laodong Guo, Wen-Xiong Wang
The Jiulong River estuary, located in the southeastern China, suffered from metal pollution due to industrial effluent releases. Mixing of effluent and estuarine water may have significantly affected the size distribution of trace metals and their environmental fate. In the present study, colloidal size distribution of organic matter and selected metals were quantified using asymmetric flow field-flow fractionation (AF4) and ICP-MS. We demonstrated a dominance of dissolved metals in the 1-10kDa fraction, and metals such as Cu, Zn, Ni, Co, Pb, Cd and Mn were mostly regulated by terrestrial fulvic acid...
June 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28640904/correlation-of-disease-severity-with-body-weight-and-high-fat-diet-in-the-fatzo-pco-mouse
#14
Brian A Droz, Bria L Sneed, Charles V Jackson, Karen M Zimmerman, M Dodson Michael, Paul J Emmerson, Tamer Coskun, Richard G Peterson
Obesity in many current pre-clinical animal models of obesity and diabetes is mediated by monogenic mutations; these are rarely associated with the development of human obesity. A new mouse model, the FATZO mouse, has been developed to provide polygenic obesity and a metabolic pattern of hyperglycemia and hyperinsulinemia, that support the presence of insulin resistance similar to metabolic disease in patients with insulin resistance/type 2 diabetes. The FATZO mouse resulted from a cross of C57BL/6J and AKR/J mice followed by selective inbreeding for obesity, increased insulin and hyperglycemia...
2017: PloS One
https://www.readbyqxmd.com/read/28638080/thermoelectric-performance-of-n-type-mg2ge
#15
Rafael Santos, Mitchell Nancarrow, Shi Xue Dou, Sima Aminorroaya Yamini
Magnesium-based thermoelectric materials (Mg2X, X = Si, Ge, Sn) have received considerable attention due to their availability, low toxicity, and reasonably good thermoelectric performance. The synthesis of these materials with high purity is challenging, however, due to the reactive nature and high vapour pressure of magnesium. In the current study, high purity single phase n-type Mg2Ge has been fabricated through a one-step reaction of MgH2 and elemental Ge, using spark plasma sintering (SPS) to reduce the formation of magnesium oxides due to the liberation of hydrogen...
June 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28637861/epidemic-and-endemic-pathogen-dynamics-correspond-to-distinct-host-population-microbiomes-at-a-landscape-scale
#16
Andrea J Jani, Roland A Knapp, Cheryl J Briggs
Infectious diseases have serious impacts on human and wildlife populations, but the effects of a disease can vary, even among individuals or populations of the same host species. Identifying the reasons for this variation is key to understanding disease dynamics and mitigating infectious disease impacts, but disentangling cause and correlation during natural outbreaks is extremely challenging. This study aims to understand associations between symbiotic bacterial communities and an infectious disease, and examines multiple host populations before or after pathogen invasion to infer likely causal links...
June 28, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28637810/mcclintock-an-integrated-pipeline-for-detecting-transposable-element-insertions-in-whole-genome-shotgun-sequencing-data
#17
Michael G Nelson, Raquel S Linheiro, Casey M Bergman
Transposable element (TE) insertions are among the most challenging type of variants to detect in genomic data because of their repetitive nature and complex mechanisms of replication. Nevertheless, the recent availability of large resequencing datasets has spurred development of many new methods to detect TE insertions in whole genome shotgun sequences. Here we report an integrated bioinformatics pipeline for the detection of TE insertions in whole genome shotgun data, called McClintock (https://github.com/bergmanlab/mcclintock), which automatically runs and standardizes output for multiple TE detection methods...
June 21, 2017: G3: Genes—Genomes—Genetics
https://www.readbyqxmd.com/read/28637217/experimental-support-that-natural-selection-has-shaped-the-latitudinal-distribution-of-mitochondrial-haplotypes-in-australian-drosophila-melanogaster
#18
M Florencia Camus, Jonci N Wolff, Carla M Sgrò, Damian K Dowling
Cellular metabolism is regulated by enzyme complexes within the mitochondrion, the function of which are sensitive to the prevailing temperature. Such thermal sensitivity, coupled with the observation that population frequencies of mitochondrial haplotypes tend to associate with latitude, altitude or climatic regions across species distributions, led to the hypothesis that thermal selection has played a role in shaping standing variation in the mitochondrial DNA (mtDNA) sequence. This hypothesis, however, remains controversial, and requires evidence that the distribution of haplotypes observed in nature corresponds with the capacity of these haplotypes to confer differences in thermal tolerance...
June 20, 2017: Molecular Biology and Evolution
https://www.readbyqxmd.com/read/28637098/uncovering-the-contribution-of-epigenetics-to-plant-phenotypic-variation-in-mediterranean-ecosystems
#19
REVIEW
F Balao, O Paun, C Alonso
Epigenetic signals can affect plant phenotype and fitness and be stably inherited across multiple generations. Epigenetic regulation plays a key role in the mechanisms of plant response to the environment without altering DNA sequence. As plants cannot adapt behaviourally or migrate instantly, such dynamic epigenetic responses may be particularly crucial for survival of plants within changing and challenging environments, such as the Mediterranean-Type Ecosystems (MTEs). These ecosystems suffer recurrent stressful events (warm and dry summers with associated fire regimes) that have selected for plants with similar phenotypic complex traits, resulting in similar vegetation growth forms...
June 21, 2017: Plant Biology
https://www.readbyqxmd.com/read/28636923/mechanosensitive-adhesion-explains-stepping-motility-in-amoeboid-cells
#20
Calina A Copos, Sam Walcott, Juan C Del Álamo, Effie Bastounis, Alex Mogilner, Robert D Guy
Cells employing amoeboid motility exhibit repetitive cycles of rapid expansion and contraction and apply coordinated traction forces to their environment. Although aspects of this process are well studied, it is unclear how the cell controls the coordination of cell length changes with adhesion to the surface. Here, we develop a simple model to mechanistically explain the emergence of periodic changes in length and spatiotemporal dynamics of traction forces measured in chemotaxing unicellular amoeba, Dictyostelium discoideum...
June 20, 2017: Biophysical Journal
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