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https://www.readbyqxmd.com/read/28821587/drift-induced-selection-between-male-and-female-heterogamety
#1
Carl Veller, Pavitra Muralidhar, George W A Constable, Martin A Nowak
Evolutionary transitions between male and female heterogamety are common in both vertebrates and invertebrates. Theoretical studies of these transitions have found that, when all genotypes are equally fit, continuous paths of intermediate equilibria link the two sex chromosome systems. This observation has led to a belief that neutral evolution along these paths can drive transitions, and that arbitrarily small fitness differences among sex chromosome genotypes can determine the system to which evolution leads...
August 16, 2017: Genetics
https://www.readbyqxmd.com/read/28821561/zika-virus-activates-de-novo-and-cross-reactive-memory-b-cell-responses-in-dengue-experienced-donors
#2
Thomas F Rogers, Eileen C Goodwin, Bryan Briney, Devin Sok, Nathan Beutler, Alexander Strubel, Rebecca Nedellec, Khoa Le, Michael E Brown, Dennis R Burton, Laura M Walker
Zika virus (ZIKV) shares a high degree of homology with dengue virus (DENV), suggesting that preexisting immunity to DENV could affect immune responses to ZIKV. We have tracked the evolution of ZIKV-induced B cell responses in three DENV-experienced donors. The acute antibody (plasmablast) responses were characterized by relatively high somatic hypermutation and a bias toward DENV binding and neutralization, implying the early activation of DENV clones. A DENV-naïve donor in contrast showed a classical primary plasmablast response...
August 18, 2017: Science Immunology
https://www.readbyqxmd.com/read/28820219/mo-doped-ni2p-nanowire-arrays-an-efficient-electrocatalyst-for-the-hydrogen-evolution-reaction-with-enhanced-activity-at-all-ph-values
#3
Yiqiang Sun, Lifeng Hang, Qi Shen, Tao Zhang, Huilin Li, Xiaomin Zhang, Xianjun Lyu, Yue Li
We report the successful synthesis of Mo doped Ni2P nanowires (NWs) on a Ni foam (NF) substrate by a two-step strategy, which could be used as an efficient and stable hydrogen evolution reaction (HER) electrocatalyst over the whole pH range (0-14). Electrochemical investigations demonstrated that Mo doping made the catalytic activity of Ni2P significantly enhanced. To achieve a current density of 10 mA cm(-2), Mo-Ni2P NWs/NF required an overpotential of 67 mV in acidic solution, 78 mV in alkaline solution and 84 mV in neutral solution...
August 18, 2017: Nanoscale
https://www.readbyqxmd.com/read/28820214/mediated-water-electrolysis-in-biphasic-systems
#4
Micheál D Scanlon, Pekka Peljo, Lucie Rivier, Heron Vrubel, Hubert H Girault
The concept of efficient electrolysis by linking photoelectrochemical biphasic H2 evolution and water oxidation processes in the cathodic and anodic compartments of an H-cell, respectively, is introduced. Overpotentials at the cathode and anode are minimised by incorporating light-driven elements into both biphasic reactions. The concepts viability is demonstrated by electrochemical H2 production from water splitting utilising a polarised water-organic interface in the cathodic compartment of a prototype H-cell...
August 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28819272/rapid-peat-accumulation-favours-the-occurrence-of-both-fen-and-bog-microbial-communities-within-a-mediterranean-free-floating-peat-island
#5
Giuseppe Concheri, Piergiorgio Stevanato, Claudio Zaccone, William Shotyk, Valeria D'Orazio, Teodoro Miano, Pietro Piffanelli, Valeria Rizzi, Chiara Ferrandi, Andrea Squartini
The unique environment of a 4m-thick, free-floating peat island within the Posta Fibreno lake (Central Italy) was analyzed using DNA-based techniques to assess bacterial and fungal community members identity and abundance. Two depths were sampled at 41 and 279 cm from the surface, the former corresponding to an emerged portion of Sphagnum residues accumulated less than 30 yrs ago, and the latter mainly consisting of silty peat belonging to the deeply submerged part of the island, dating back to 1520-1660 AD...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28818621/codon-usage-bias-in-the-n-gene-of-rabies-virus
#6
Wanting He, Hongyu Zhang, Yuchen Zhang, Ruyi Wang, Sijia Lu, Yanjie Ji, Chang Liu, Pengkun Yuan, Shuo Su
Since its emergence, rabies virus (RABV) has been a major worldwide concern especially in developing countries. The nucleoprotein (N) of RABV is highly conserved and key for genetic typing, thus a better understanding of the N gene evolutionary trajectory can assist the development of control measures. We found that the N gene of RABV has a low codon usage bias with a mean effective number of codons (ENC) value of 56.33 influenced by both mutation pressure and natural selection. However, neutrality analysis indicated that natural selection dominates over mutation pressure...
August 14, 2017: Infection, Genetics and Evolution
https://www.readbyqxmd.com/read/28817279/soft-chemical-fabrication-of-iron-based-thin-film-electrocatalyst-for-water-oxidation-under-neutral-ph-and-structure-activity-tuning-by-cerium-incorporation
#7
Jony Saha, T P Radhakrishnan
Design of electrocatalysts for the fundamentally important oxygen evolution reaction can be greatly aided by systematic structure-activity tuning via composition variation. We have explored the iron-cerium system as they are the most abundant transition and rare earth metals, and also due to the mutualistic impact of their size and electronic attributes that can induce critical changes in the structure and electrochemical activity. Submicrometer thick films of a series of Fe(III)-Ce(III) phosphate(oxyhydroxide) (FeCePH) are fabricated using a soft chemical strategy involving surfactant-aided assembly, spin-coating, and mild thermal annealing...
August 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28811388/hill-robertson-interference-reduces-genetic-diversity-on-a-young-plant-y-chromosome
#8
Josh Hough, Wei Wang, Spencer C H Barrett, Stephen I Wright
X and Y chromosomes differ in effective population size (Ne ), rates of recombination, and exposure to natural selection, all of which can affect patterns of genetic diversity. On Y chromosomes with suppressed recombination, natural selection is expected to eliminate linked neutral variation and lower the Ne of Y compared to X chromosomes or autosomes. However, female-biased sex ratios and high variance in male reproductive success can also reduce Y-linked Ne , making it difficult to infer the causes of low Y-diversity...
August 15, 2017: Genetics
https://www.readbyqxmd.com/read/28811387/selection-constrains-high-rates-of-tandem-repetitive-dna-mutation-in-daphnia-pulex
#9
Jullien M Flynn, Ian Caldas, Melania E Cristescu, Andrew G Clark
A long-standing evolutionary puzzle is that all eukaryotic genomes contain large amounts of tandemly-repeated DNA whose sequence motifs and abundance vary greatly among even closely related species. To elucidate the evolutionary forces governing tandem repeat dynamics, quantification of the rates and patterns of mutations in repeat copy number and tests of its selective neutrality are necessary. Here we used whole-genome sequences of 28 mutation accumulation (MA) lines of Daphnia pulex in addition to six isolates from a non-MA population originating from the same progenitor to both estimate mutation rates of abundances of repeat sequences and evaluate the selective regime acting upon them...
August 15, 2017: Genetics
https://www.readbyqxmd.com/read/28809850/function-related-replacement-of-bacterial-siderophore-pathways
#10
Hilke Bruns, Max Crüsemann, Anne-Catrin Letzel, Mohammad Alanjary, James O McInerney, Paul R Jensen, Stefan Schulz, Bradley S Moore, Nadine Ziemert
Bacterial genomes are rife with orphan biosynthetic gene clusters (BGCs) associated with secondary metabolism of unrealized natural product molecules. Often up to a tenth of the genome is predicted to code for the biosynthesis of diverse metabolites with mostly unknown structures and functions. This phenomenal diversity of BGCs coupled with their high rates of horizontal transfer raise questions about whether they are really active and beneficial, whether they are neutral and confer no advantage, or whether they are carried in genomes because they are parasitic or addictive...
August 15, 2017: ISME Journal
https://www.readbyqxmd.com/read/28803874/range-expansion-compromises-adaptive-evolution-in-an-outcrossing-plant
#11
Santiago C González-Martínez, Kate Ridout, John R Pannell
Neutral genetic diversity gradients have long been used to infer the colonization history of species [1, 2], but range expansion may also influence the efficacy of natural selection and patterns of non-synonymous polymorphism in different parts of a species' range [3]. Recent theory predicts both an accumulation of deleterious mutations and a reduction in the efficacy of positive selection as a result of range expansion [4-8]. These signatures have been sought in a number of studies of the human range expansion out of Africa, but with contradictory results [9-14]...
August 4, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28798759/genome-size-diversity-in-lilium-liliaceae-is-correlated-with-karyotype-and-environmental-traits
#12
Yun-Peng Du, Yu Bi, Ming-Fang Zhang, Feng-Ping Yang, Gui-Xia Jia, Xiu-Hai Zhang
Genome size (GS) diversity is of fundamental biological importance. The occurrence of giant genomes in angiosperms is restricted to just a few lineages in the analyzed genome size of plant species so far. It is still an open question whether GS diversity is shaped by neutral or natural selection. The genus Lilium, with giant genomes, is phylogenetically and horticulturally important and is distributed throughout the northern hemisphere. GS diversity in Lilium and the underlying evolutionary mechanisms are poorly understood...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28797164/universal-surface-engineering-of-transition-metals-for-superior-electrocatalytic-hydrogen-evolution-in-neutral-water
#13
Bo You, Xuan Liu, Guoxiang Hu, Sheraz Gul, Junko Yano, De-En Jiang, Yujie Sun
The development of low-cost hybrid water splitting-biosynthetic systems that mimic natural photosynthesis to achieve solar-to-chemical conversion is of great promise for future energy demands, but often limited by the kinetically sluggish H2 evolu-tion reaction (HER) on the surface of nonprecious transition metal catalysts in neutral media. It is thus highly desirable to rationally tailor the reaction interface to boost the neutral HER catalytic kinetics. Herein, we report a general surface nitro-gen modification of diverse transition metals (e...
August 10, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28793206/a-model-for-viral-assembly-around-an-explicit-rna-sequence-generates-an-implicit-fitness-landscape
#14
Eric Charles Dykeman
Previously, a stochastic model of single-stranded RNA virus assembly was created to model the cooperative effects between capsid proteins and genomic RNA that would occur in a packaging signal-mediated assembly process. In such an assembly scenario, multiple secondary structural elements from within the RNA, termed "packaging signals" (PS), contact coat proteins and facilitate efficient capsid assembly. In this work, the assembly model is extended to incorporate explicit nucleotide sequence information as well as simple aspects of RNA folding that would be occurring during the RNA/capsid coassembly process...
August 8, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28792889/uncoupling-evolutionary-changes-in-dna-sequence-transcription-factor-occupancy-and-enhancer-activity
#15
Pierre Khoueiry, Charles Girardot, Lucia Ciglar, Pei-Chen Peng, E Hilary Gustafson, Saurabh Sinha, Eileen Em Furlong
Sequence variation within enhancers plays a major role in both evolution and disease, yet its functional impact on transcription factor (TF) occupancy and enhancer activity remains poorly understood. Here, we assayed the binding of five essential TFs over multiple stages of embryogenesis in two distant Drosophila species (with 1.4 substitutions per neutral site), identifying thousands of orthologous enhancers with conserved or diverged combinatorial occupancy. We used these binding signatures to dissect two properties of developmental enhancers: (1) potential TF cooperativity, using signatures of co-associations and co-divergence in TF occupancy...
August 9, 2017: ELife
https://www.readbyqxmd.com/read/28790414/modelling-the-evolution-of-transcription-factor-binding-preferences-in-complex-eukaryotes
#16
Antonio Rosanova, Alberto Colliva, Matteo Osella, Michele Caselle
Transcription factors (TFs) exert their regulatory action by binding to DNA with specific sequence preferences. However, different TFs can partially share their binding sequences due to their common evolutionary origin. This "redundancy" of binding defines a way of organizing TFs in "motif families" by grouping TFs with similar binding preferences. Since these ultimately define the TF target genes, the motif family organization entails information about the structure of transcriptional regulation as it has been shaped by evolution...
August 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28783217/a-novel-phase-transformation-activation-process-toward-ni-mn-o-nanoprism-arrays-for-2-4-v-ultrahigh-voltage-aqueous-supercapacitors
#17
Wenhua Zuo, Chaoyue Xie, Pan Xu, Yuanyuan Li, Jinping Liu
One of the key challenges of aqueous supercapacitors is the relatively low voltage (0.8-2.0 V), which significantly limits the energy density and feasibility of practical applications of the device. Herein, this study reports a novel Ni-Mn-O solid-solution cathode to widen the supercapacitor device voltage, which can potentially suppress the oxygen evolution reaction and thus be operated stably within a quite wide potential window of 0-1.4 V (vs saturated calomel electrode) after a simple but unique phase-transformation electrochemical activation...
August 7, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28782550/contribution-of-gene-flow-to-the-evolution-of-recombination-suppression-in-sex-chromosomes
#18
Tomotaka Matsumoto, Kohta Yoshida, Jun Kitano
Polymorphism of alleles that benefit one sex but harm the other (sexually antagonistic alleles) generates selective pressures for reduced recombination between themselves and sex-determination loci. Such polymorphism can be maintained within a population when selection coefficients are sufficiently balanced between males and females. However, if regulatory mutations restrict gene expression only to one sex, these alleles become neutral in the other sex and easily fixed within a population, removing the selective pressures for recombination suppression in sex chromosomes...
August 3, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28782044/evolution-of-complex-adaptations-in-molecular-systems
#19
Csaba Pál, Balázs Papp
A central challenge in evolutionary biology concerns the mechanisms by which complex adaptations arise. Such adaptations depend on the fixation of multiple, highly specific mutations, where intermediate stages of evolution seemingly provide little or no benefit. It is generally assumed that the establishment of complex adaptations is very slow in nature, as evolution of such traits demands special population genetic or environmental circumstances. However, blueprints of complex adaptations in molecular systems are pervasive, indicating that they can readily evolve...
August 2017: Nature ecology & evolution
https://www.readbyqxmd.com/read/28773978/roles-of-bulk-and-surface-chemistry-in-the-oxygen-exchange-kinetics-and-related-properties-of-mixed-conducting-perovskite-oxide-electrodes
#20
REVIEW
Nicola H Perry, Tatsumi Ishihara
Mixed conducting perovskite oxides and related structures serving as electrodes for electrochemical oxygen incorporation and evolution in solid oxide fuel and electrolysis cells, respectively, play a significant role in determining the cell efficiency and lifetime. Desired improvements in catalytic activity for rapid surface oxygen exchange, fast bulk transport (electronic and ionic), and thermo-chemo-mechanical stability of oxygen electrodes will require increased understanding of the impact of both bulk and surface chemistry on these properties...
October 21, 2016: Materials
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