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61.
Kawaguchi S Kilpatrick R Roberts L King RA Nicol S 《Journal of plankton research》2011,33(7):1134-1138
For the first time the entire sequence of the mating behaviour of Antarctic krill (Euphausia superba) in the wild is captured on underwater video. This footage also provides evidence that mating can take place near the seafloor at depths of 400-700 m. This observation challenges the generally accepted concept of the pelagic lifestyle of krill. The mating behaviour observed most closely resembles the mating behaviour reported for a decapod shrimp (Penaeus). The implications of the new observation are also discussed. 相似文献
62.
John E. McKinnon Robbie B. Mailliard Susan Swindells Timothy J. Wilkin LuAnn Borowski Jillian M. Roper Barbara Bastow Mary Kearney Ann Wiegand John W. Mellors Charles R. Rinaldo for the A study team 《PloS one》2014,9(5)
Objectives
Simplified maintenance therapy with ritonavir-boosted atazanavir (ATV/r) provides an alternative treatment option for HIV-1 infection that spares nucleoside analogs (NRTI) for future use and decreased toxicity. We hypothesized that the level of immune activation (IA) and recovery of lymphocyte populations could influence virologic outcomes after regimen simplification.Methods
Thirty-four participants with virologic suppression ≥48 weeks on antiretroviral therapy (2 NRTI plus protease inhibitor) were switched to ATV/r alone in the context of the ACTG 5201 clinical trial. Flow cytometric analyses were performed on PBMC isolated from 25 patients with available samples, of which 24 had lymphocyte recovery sufficient for this study. Assessments included enumeration of T-cells (CD4/CD8), natural killer (NK) (CD3+CD56+CD16+) cells and cell-associated markers (HLA-DR, CD''s 38/69/94/95/158/279).Results
Eight of the 24 patients had at least one plasma HIV-1 RNA level (VL) >50 copies/mL during the study. NK cell levels below the group median of 7.1% at study entry were associated with development of VL >50 copies/mL following simplification by regression and survival analyses (p = 0.043 and 0.023), with an odds ratio of 10.3 (95% CI: 1.92–55.3). Simplification was associated with transient increases in naïve and CD25+ CD4+ T-cells, and had no impact on IA levels.Conclusions
Lower NK cell levels prior to regimen simplification were predictive of virologic rebound after discontinuation of nucleoside analogs. Regimen simplification did not have a sustained impact on markers of IA or T lymphocyte populations in 48 weeks of clinical monitoring.Trial Registration
ClinicalTrials.gov NCT00084019相似文献63.
64.
Marcel A. L. M. van Assen Robbie C. M. van Aert Michèle B. Nuijten Jelte M. Wicherts 《PloS one》2014,9(1)
Background
De Winter and Happee [1] examined whether science based on selective publishing of significant results may be effective in accurate estimation of population effects, and whether this is even more effective than a science in which all results are published (i.e., a science without publication bias). Based on their simulation study they concluded that “selective publishing yields a more accurate meta-analytic estimation of the true effect than publishing everything, (and that) publishing nonreplicable results while placing null results in the file drawer can be beneficial for the scientific collective” (p.4).Methods and Findings
Using their scenario with a small to medium population effect size, we show that publishing everything is more effective for the scientific collective than selective publishing of significant results. Additionally, we examined a scenario with a null effect, which provides a more dramatic illustration of the superiority of publishing everything over selective publishing.Conclusion
Publishing everything is more effective than only reporting significant outcomes. 相似文献65.
María Mu?oz-Amatriaín Alfonso Cuesta-Marcos Jeffrey B. Endelman Jordi Comadran John M. Bonman Harold E. Bockelman Shiaoman Chao Joanne Russell Robbie Waugh Patrick M. Hayes Gary J. Muehlbauer 《PloS one》2014,9(4)
New sources of genetic diversity must be incorporated into plant breeding programs if they are to continue increasing grain yield and quality, and tolerance to abiotic and biotic stresses. Germplasm collections provide a source of genetic and phenotypic diversity, but characterization of these resources is required to increase their utility for breeding programs. We used a barley SNP iSelect platform with 7,842 SNPs to genotype 2,417 barley accessions sampled from the USDA National Small Grains Collection of 33,176 accessions. Most of the accessions in this core collection are categorized as landraces or cultivars/breeding lines and were obtained from more than 100 countries. Both STRUCTURE and principal component analysis identified five major subpopulations within the core collection, mainly differentiated by geographical origin and spike row number (an inflorescence architecture trait). Different patterns of linkage disequilibrium (LD) were found across the barley genome and many regions of high LD contained traits involved in domestication and breeding selection. The genotype data were used to define ‘mini-core’ sets of accessions capturing the majority of the allelic diversity present in the core collection. These ‘mini-core’ sets can be used for evaluating traits that are difficult or expensive to score. Genome-wide association studies (GWAS) of ‘hull cover’, ‘spike row number’, and ‘heading date’ demonstrate the utility of the core collection for locating genetic factors determining important phenotypes. The GWAS results were referenced to a new barley consensus map containing 5,665 SNPs. Our results demonstrate that GWAS and high-density SNP genotyping are effective tools for plant breeders interested in accessing genetic diversity in large germplasm collections. 相似文献
66.
Abdellah Barakate James D. Higgins Sebastian Vivera Jennifer Stephens Ruth M. Perry Luke Ramsay Isabelle Colas Helena Oakey Robbie Waugh F. Chris H. Franklin Susan J. Armstrong Claire Halpin 《The Plant cell》2014,26(2):729-740
In many cereal crops, meiotic crossovers predominantly occur toward the ends of
chromosomes and 30 to 50% of genes rarely recombine. This limits the exploitation of
genetic variation by plant breeding. Previous reports demonstrate that chiasma
frequency can be manipulated in plants by depletion of the synaptonemal complex
protein ZIPPER1 (ZYP1) but conflict as to the direction of change, with fewer
chiasmata reported in Arabidopsis thaliana and more crossovers
reported for rice (Oryza sativa). Here, we use RNA interference
(RNAi) to reduce the amount of ZYP1 in
barley (Hordeum vulgare) to only 2 to 17% of normal zygotene levels.
In the ZYP1RNAi lines, fewer than half of the chromosome
pairs formed bivalents at metaphase and many univalents were observed, leading to
chromosome nondisjunction and semisterility. The number of chiasmata per cell was
reduced from 14 in control plants to three to four in the ZYP1-depleted lines,
although the localization of residual chiasmata was not affected. DNA double-strand
break formation appeared normal, but the recombination pathway was defective at later
stages. A meiotic time course revealed a 12-h delay in prophase I progression to the
first labeled tetrads. Barley ZYP1 appears to function similarly to ZIP1/ZYP1 in
yeast and Arabidopsis, with an opposite effect on crossover number
to ZEP1 in rice, another member of the Poaceae. 相似文献
67.
68.
Robbie IAnson Price Francisca Segers Amelia Berger Fabio S Nascimento Christoph Grüter 《动物学报(英文版)》2021,67(5):551
Social information is widely used in the animal kingdom and can be highly adaptive. In social insects, foragers can use social information to find food, avoid danger, or choose a new nest site. Copying others allows individuals to obtain information without having to sample the environment. When foragers communicate information they will often only advertise high-quality food sources, thereby filtering out less adaptive information. Stingless bees, a large pantropical group of highly eusocial bees, face intense inter- and intra-specific competition for limited resources, yet display disparate foraging strategies. Within the same environment there are species that communicate the location of food resources to nest-mates and species that do not. Our current understanding of why some species communicate foraging sites while others do not is limited. Studying freely foraging colonies of several co-existing stingless bee species in Brazil, we investigated if recruitment to specific food locations is linked to 1) the sugar content of forage, 2) the duration of foraging trips, and 3) the variation in activity of a colony from 1 day to another and the variation in activity in a species over a day. We found that, contrary to our expectations, species with recruitment communication did not return with higher quality forage than species that do not recruit nestmates. Furthermore, foragers from recruiting species did not have shorter foraging trip durations than those from weakly recruiting species. Given the intense inter- and intraspecific competition for resources in these environments, it may be that recruiting species favor food resources that can be monopolized by the colony rather than food sources that offer high-quality rewards. 相似文献
69.
Robbie A. Hember Werner A. Kurz Juha M. Metsaranta T. Andy Black Robert D. Guy Nicholas C. Coops 《Global Change Biology》2012,18(6):2026-2040
To understand how environmental changes have influenced forest productivity, stemwood biomass (B) dynamics were analyzed at 1267 permanent inventory plots, covering a combined 209 ha area of unmanaged temperate‐maritime forest in southwest British Columbia, Canada. Net stemwood production (ΔB) was derived from periodic remeasurements of B collected over a 40‐year measurement period (1959–1998) in stands ranging from 20 to 150 years old. Comparison between the integrated age response of net stemwood production, ΔB(A), and the age response of stemwood biomass, B(A), suggested a 58 ± 11% increase in ΔB between the first 40 years of the chronosequence period (1859–1898) and the measurement period. To estimate extrinsic forcing on ΔB, several different candidate models were developed to remove variation explained by intrinsic factors. All models exhibited temporal bias, with positive trends in (observed minus predicted) residual ΔB ranging between of 0.40 and 0.64% yr?1. Applying the same methods to stemwood growth (G) indicated residual increases ranging from 0.43 and 0.67% yr?1. Higher trend estimates corresponded with models that included site index (SI) as a predictor, which may reflect exaggeration of the age‐decline in SI tables. Choosing a model that excluded SI, suggested that ΔB increased by 0.40 ± 0.18% yr?1, while G increased by 0.43 ± 0.12% yr?1 over the measurement period. Residual G was significantly correlated with atmospheric carbon dioxide (CO2), temperature (T), and climate moisture index (CMI). However, models driven with climate and CO2, alone, could not simultaneously explain long‐term and measurement‐period trends without additional representation of indirect effects, perhaps reflecting compound interest on direct physiological responses to environmental change. Evidence of accelerating forest regrowth highlights the value of permanent inventories to detect and understand systematic changes in forest productivity caused by environmental change. 相似文献
70.
Daniela Bustos‐Korts Ian K. Dawson Joanne Russell Alessandro Tondelli Davide Guerra Chiara Ferrandi Francesco Strozzi Ezequiel L. Nicolazzi Marta Molnar‐Lang Hakan Ozkan Maria Megyeri Peter Miko Esra akr Enes Yakr Noemi Trabanco Stefano Delbono Stylianos Kyriakidis Allan Booth Davide Cammarano Martin Mascher Peter Werner Luigi Cattivelli Laura Rossini Nils Stein Benjamin Kilian Robbie Waugh Fred A. van Eeuwijk 《The Plant journal : for cell and molecular biology》2019,99(6):1172-1191
Broadening the genetic base of crops is crucial for developing varieties to respond to global agricultural challenges such as climate change. Here, we analysed a diverse panel of 371 domesticated lines of the model crop barley to explore the genetics of crop adaptation. We first collected exome sequence data and phenotypes of key life history traits from contrasting multi‐environment common garden trials. Then we applied refined statistical methods, including some based on exomic haplotype states, for genotype‐by‐environment (G×E) modelling. Sub‐populations defined from exomic profiles were coincident with barley's biology, geography and history, and explained a high proportion of trial phenotypic variance. Clear G×E interactions indicated adaptation profiles that varied for landraces and cultivars. Exploration of circadian clock‐related genes, associated with the environmentally adaptive days to heading trait (crucial for the crop's spread from the Fertile Crescent), illustrated complexities in G×E effect directions, and the importance of latitudinally based genic context in the expression of large‐effect alleles. Our analysis supports a gene‐level scientific understanding of crop adaption and leads to practical opportunities for crop improvement, allowing the prioritisation of genomic regions and particular sets of lines for breeding efforts seeking to cope with climate change and other stresses. 相似文献