348 research outputs found

    Sensory Measurements: Coordination and Standardization

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    Do sensory measurements deserve the label of “measurement”? We argue that they do. They fit with an epistemological view of measurement held in current philosophy of science, and they face the same kinds of epistemological challenges as physical measurements do: the problem of coordination and the problem of standardization. These problems are addressed through the process of “epistemic iteration,” for all measurements. We also argue for distinguishing the problem of standardization from the problem of coordination. To exemplify our claims, we draw on olfactory performance tests, especially studies linking olfactory decline to neurodegenerative disorders

    Potentials of Mean Force for Protein Structure Prediction Vindicated, Formalized and Generalized

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    Understanding protein structure is of crucial importance in science, medicine and biotechnology. For about two decades, knowledge based potentials based on pairwise distances -- so-called "potentials of mean force" (PMFs) -- have been center stage in the prediction and design of protein structure and the simulation of protein folding. However, the validity, scope and limitations of these potentials are still vigorously debated and disputed, and the optimal choice of the reference state -- a necessary component of these potentials -- is an unsolved problem. PMFs are loosely justified by analogy to the reversible work theorem in statistical physics, or by a statistical argument based on a likelihood function. Both justifications are insightful but leave many questions unanswered. Here, we show for the first time that PMFs can be seen as approximations to quantities that do have a rigorous probabilistic justification: they naturally arise when probability distributions over different features of proteins need to be combined. We call these quantities reference ratio distributions deriving from the application of the reference ratio method. This new view is not only of theoretical relevance, but leads to many insights that are of direct practical use: the reference state is uniquely defined and does not require external physical insights; the approach can be generalized beyond pairwise distances to arbitrary features of protein structure; and it becomes clear for which purposes the use of these quantities is justified. We illustrate these insights with two applications, involving the radius of gyration and hydrogen bonding. In the latter case, we also show how the reference ratio method can be iteratively applied to sculpt an energy funnel. Our results considerably increase the understanding and scope of energy functions derived from known biomolecular structures

    Developmental features of cotton fibre middle lamellae in relation to cell adhesion and cell detachment in cultivars with distinct fibre qualities.

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    Background: Cotton fibre quality traits such as fibre length, strength, and degree of maturation are determined by genotype and environment during the sequential phases of cotton fibre development (cell elongation, transition to secondary cell wall construction and cellulose deposition). The cotton fibre middle lamella (CFML) is crucial for both cell adhesion and detachment processes occurring during fibre development. To explore the relationship between fibre quality and the pace at which cotton fibres develop, a structural and compositional analysis of the CFML was carried out in several cultivars with different fibre properties belonging to four commercial species: Gossypium hirsutum, G. barbadense, G. herbaceum and G. arboreum. Results: Cotton fibre cell adhesion, through the cotton fibre middle lamella (CFML), is a developmentally regulated process determined by genotype. The CFML is composed of de-esterified homogalacturonan, xyloglucan and arabinan in all four fibre-producing cotton species: G. hirsutum, G. barbadense, G. herbaceum and G. arboreum. Conspicuous paired cell wall bulges are a feature of the CFML of two G. hirsutum cultivars from the onset of fibre cell wall detachment to the start of secondary cell wall deposition. Xyloglucan is abundant in the cell wall bulges and in later stages pectic arabinan is absent from these regions. Conclusions: The CFML of cotton fibres is re-structured during the transition phase. Paired cell wall bulges, rich in xyloglucan, are significantly more evident in the G. hirsutum cultivars than in other cotton species

    Lateral adhesion drives reintegration of misplaced cells into epithelial monolayers.

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    Cells in simple epithelia orient their mitotic spindles in the plane of the epithelium so that both daughter cells are born within the epithelial sheet. This is assumed to be important to maintain epithelial integrity and prevent hyperplasia, because misaligned divisions give rise to cells outside the epithelium. Here we test this assumption in three types of Drosophila epithelium; the cuboidal follicle epithelium, the columnar early embryonic ectoderm, and the pseudostratified neuroepithelium. Ectopic expression of Inscuteable in these tissues reorients mitotic spindles, resulting in one daughter cell being born outside the epithelial layer. Live imaging reveals that these misplaced cells reintegrate into the tissue. Reducing the levels of the lateral homophilic adhesion molecules Neuroglian or Fasciclin 2 disrupts reintegration, giving rise to extra-epithelial cells, whereas disruption of adherens junctions has no effect. Thus, the reinsertion of misplaced cells seems to be driven by lateral adhesion, which pulls cells born outside the epithelial layer back into it. Our findings reveal a robust mechanism that protects epithelia against the consequences of misoriented divisions.The authors are grateful to R. Nieuwburg, the St Johnston group, and other Gurdon Institute members for suggestions. We thank the Bloomington Stock Center, J. Knoblich, and the TRiP at Harvard Medical School (NIH/NIGMS R01-GM084947) for fly stocks. We thank N. Lowe for technical assistance. This work was supported by a Wellcome Trust Principal Fellowship to D.St.J. (080007), and by core support from the Wellcome Trust (092096) and Cancer Research UK (A14492). D.T.B. was supported by a Marie Curie Fellowship and the Wellcome Trust. H.E.L. was supported by a Herchel Smith Studentship.This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/ncb324

    Vaccinia Virus G8R Protein: A Structural Ortholog of Proliferating Cell Nuclear Antigen (PCNA)

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    BACKGROUND: Eukaryotic DNA replication involves the synthesis of both a DNA leading and lagging strand, the latter requiring several additional proteins including flap endonuclease (FEN-1) and proliferating cell nuclear antigen (PCNA) in order to remove RNA primers used in the synthesis of Okazaki fragments. Poxviruses are complex viruses (dsDNA genomes) that infect eukaryotes, but surprisingly little is known about the process of DNA replication. Given our previous results that the vaccinia virus (VACV) G5R protein may be structurally similar to a FEN-1-like protein and a recent finding that poxviruses encode a primase function, we undertook a series of in silico analyses to identify whether VACV also encodes a PCNA-like protein. RESULTS: An InterProScan of all VACV proteins using the JIPS software package was used to identify any PCNA-like proteins. The VACV G8R protein was identified as the only vaccinia protein that contained a PCNA-like sliding clamp motif. The VACV G8R protein plays a role in poxvirus late transcription and is known to interact with several other poxvirus proteins including itself. The secondary and tertiary structure of the VACV G8R protein was predicted and compared to the secondary and tertiary structure of both human and yeast PCNA proteins, and a high degree of similarity between all three proteins was noted. CONCLUSIONS: The structure of the VACV G8R protein is predicted to closely resemble the eukaryotic PCNA protein; it possesses several other features including a conserved ubiquitylation and SUMOylation site that suggest that, like its counterpart in T4 bacteriophage (gp45), it may function as a sliding clamp ushering transcription factors to RNA polymerase during late transcription

    A cross-sectional survey of the prevalence of environmental tobacco smoke preventive care provision by child health services in Australia

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    Background: Despite the need for a reduction in levels of childhood exposure to environmental tobacco smoke (ETS) being a recognised public health goal, the delivery of ETS preventive care in child health service settings remains a largely unstudied area. The purpose of this study was to determine the prevalence of ETS preventive care in child health services; differences in the provision of care by type of service; the prevalence of strategies to support such care; and the association between care support strategies and care provision. Method: One-hundred and fifty-one (83%) child health service managers within New South Wales, Australia completed a questionnaire in 2002 regarding the: assessment of parental smoking and child ETS exposure; the provision of parental smoking cessation and ETS-exposure reduction advice; and strategies used to support the provision of such care. Child health services were categorised based on their size and case-mix, and a chi-square analysis was performed to compare the prevalence of ETS risk assessment and ETS prevention advice between service types. Logistic regression analysis was used to examine associations between the existence of care support strategies and the provision of ETS risk assessment and ETS exposure prevention advice. Results: A significant proportion of services reported that they did not assess parental smoking status (26%), and reported that they did not assess the ETS exposure (78%) of any child. Forty four percent of services reported that they did not provide smoking cessation advice and 20% reported they did not provide ETS exposure prevention advice. Community based child and family health services reported a greater prevalence of ETS preventive care compared to other hospital based units. Less than half of the services reported having strategies to support the provision of ETS preventive care. The existence of such support strategies was associated with greater odds of care provision. Conclusions: The existence of major gaps in recommended ETS preventive care provision suggests a need for additional initiatives to increase such care delivery. The low prevalence of strategies that support such care delivery suggests a potential avenue to achieve this outcome

    Whole-genome resequencing of Cucurbita pepo morphotypes to discover genomic variants associated with morphology and horticulturally valuable traits

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    [EN] Cucurbita pepo contains two cultivated subspecies, each of which encompasses four fruit-shape morphotypes (cultivar groups). The Pumpkin, Vegetable Marrow, Cocozelle, and Zucchini Groups are of subsp. pepo and the Acorn, Crookneck, Scallop, and Straightneck Groups are of subsp. ovifera. Recently, a de novo assembly of the C. pepo subsp. pepo Zucchini genome was published, providing insights into its evolution. To expand our knowledge of evolutionary processes within C. pepo and to identify variants associated with particular morphotypes, we performed whole-genome resequencing of seven of these eight C. pepo morphotypes. We report for the first time whole-genome resequencing of the four subsp. pepo (Pumpkin, Vegetable Marrow, Cocozelle, green Zucchini, and yellow Zucchini) morphotypes and three of the subsp. ovifera (Acorn, Crookneck, and Scallop) morphotypes. A high-depth resequencing approach was followed, using the BGISEQ-500 platform that enables the identification of rare variants, with an average of 33.5X. Approximately 94.5% of the clean reads were mapped against the reference Zucchini genome. In total, 3,823,977 high confidence single-nucleotide polymorphisms (SNPs) were identified. Within each accession, SNPs varied from 636,918 in green Zucchini to 2,656,513 in Crookneck, and were distributed homogeneously along the chromosomes. Clear differences between subspecies pepo and ovifera in genetic variation and linkage disequilibrium are highlighted. In fact, comparison between subspecies pepo and ovifera indicated 5710 genes (22.5%) with Fst > 0.80 and 1059 genes (4.1%) with Fst = 1.00 as potential candidate genes that were fixed during the independent evolution and domestication of the two subspecies. Linkage disequilibrium was greater in subsp. ovifera than in subsp. pepo, perhaps reflective of the earlier differentiation of morphotypes within subsp. ovifera. Some morphotype-specific genes have been localized. Our results offer new clues that may provide an improved understanding of the underlying genomic regions involved in the independent evolution and domestication of the two subspecies. Comparisons among SNPs unique to particular subspecies or morphotypes may provide candidate genes responsible for traits of high economic importance.This work has been supported by Hellenic Agricultural Organization (ELGO) Demeter. Furthermore, we thank the Conselleria de Educacio, Investigacio, Cultura i Esport (Generalitat Valenciana) for funding Project Prometeo 2017/078 "Seleccion de Variedades Tradicionales y Desarrollo de Nuevas Variedades de Cucurbitaceas Adaptadas a la Produccion Ecologica". Also, this work was supported by Chiang Mai University.Xanthopoulou, A.; Montero-Pau, J.; Mellidou, I.; Kissoudis, C.; Blanca Postigo, JM.; Picó Sirvent, MB.; Tsaballa, A.... (2019). Whole-genome resequencing of Cucurbita pepo morphotypes to discover genomic variants associated with morphology and horticulturally valuable traits. Horticulture Research. 6:1-17. https://doi.org/10.1038/s41438-019-0176-9S1176Maynard, D. & Paris, H. in The Encyclopedia of Fruits & Nuts (eds Paull, R. E. & Janick, J.) 276–313 (CABI, New Jersey, U.S.A., 2018).Paris, H. S. in Genetics and Genomics of Cucurbitaceae, Grumet, Rebecca, Katzir, Nurit, Garcia-Mas, Jordi (Eds.) 111–154 (Springer, New York, U.S.A., 2016).Whitaker, T. W. & Davis, G. N. Cucurbits (Leonard Hill (Books) Ltd., London, and Interscience Publishers Inc., New York, 1962).Paris, H. S. History of the cultivar-groups of Cucurbita pepo. Hortic. Rev. 25, 71–170 (2001).Paris, H. S. A proposed subspecific classifiaction for Cucurbita pepo. Phytologia (USA) 61, 133–138 (1986).Lira, R., Andres, T. C. & Nee, M. in Systematic and Ecogeographic Studies on Crop Genepools, Vol. 9, 1–115 (International Plant Genetic Resources Institute, Roma, Italia, 1995).Castellanos-Morales, G. Historical biogeography and phylogeny of Cucurbita: insights from ancestral area reconstruction and niche evolution. Mol. Phylogenet. Evol. 128, 38–54 (2018).Paris, H. S., Lebeda, A., Křistkova, E., Andres, T. C. & Nee, M. H. Parallel evolution under domestication and phenotypic differentiation of the cultivated subspecies of Cucurbita pepo (Cucurbitaceae). Econ. Bot. 66, 71–90 (2012).Dong, W., Wu, D., Li, G., Wu, D. & Wang, Z. Next-generation sequencing from bulked segregant analysis identifies a dwarfism gene in watermelon. Sci. Rep. 8, 2908 (2018).Galpaz, N. et al. Deciphering genetic factors that determine melon fruit‐quality traits using RNA‐Seq‐based high‐resolution QTL and eQTL mapping. Plant J. 94, 169–191 (2018).Gur, A. et al. Genome-wide linkage-disequilibrium mapping to the candidate gene level in melon (Cucumis melo). Sci. Rep. 7, 9770 (2017).Blanca, J. et al. Transcriptome characterization and high throughput SSRs and SNPs discovery in Cucurbita pepo (Cucurbitaceae). BMC Genom. 12, 104 (2011).Esteras, C. et al. High-throughput SNP genotyping in Cucurbita pepo for map construction and quantitative trait loci mapping. BMC Genom. 13, 80 (2012).Montero-Pau, J. et al. An SNP-based saturated genetic map and QTL analysis of fruit-related traits in Zucchini using genotyping-by-sequencing. BMC Genom. 18, 94 (2017).Vicente-Dólera, N. et al. First TILLING platform in Cucurbita pepo: a new mutant resource for gene function and crop improvement. PLoS ONE 9, e112743 (2014).Wyatt, L. E., Strickler, S. R., Mueller, L. A. & Mazourek, M. An acorn squash (Cucurbita pepo ssp. ovifera) fruit and seed transcriptome as a resource for the study of fruit traits in Cucurbita. Hortic. Res. 2, 14070 (2015).Xanthopoulou, A. et al. De novo comparative transcriptome analysis of genes involved in fruit morphology of pumpkin cultivars with extreme size difference and development of EST-SSR markers. Gene 622, 50–66 (2017).Montero‐Pau, J. et al. De novo assembly of the zucchini genome reveals a whole‐genome duplication associated with the origin of the Cucurbita genus. Plant Biotechnol. J. 16, 1161–1171 (2018).Garcia-Mas, J. et al. Cloning and mapping of resistance gene homologues in melon. Plant Sci. 161, 165–172 (2001).Xanthopoulou, A. et al. Comparative analysis of genetic diversity in Greek Genebank collection of summer squash (‘Cucurbita pepo’) landraces using start codon targeted (SCoT) polymorphism and ISSR markers. Aust. J. Crop Sci. 9, 14 (2015).Huang, J. et al. A reference human genome dataset of the BGISEQ-500 sequencer. Gigascience 6, gix024 (2017).Natarajan, K. N. et al. Comparative analysis of sequencing technologies for single-cell transcriptomics. Genome Biol. 20, 70 (2019).Li, H. & Durbin, R. Fast and accurate short read alignment with Burrows–Wheeler transform. Bioinformatics 25, 1754–1760 (2009).Tian, L. et al. Transcript and proteomic analysis of developing white lupin (Lupinus albus L.) roots. BMC Plant Biol. 9, 1 (2009).Li, H. et al. The sequence alignment/map format and SAMtools. Bioinformatics 25, 2078–2079 (2009).McKenna, A. et al. The Genome Analysis Toolkit: a MapReduce framework for analyzing next-generation DNA sequencing data. Genome Res. 20, 1297–1303 (2010).Bradbury, P. J. et al. TASSEL: software for association mapping of complex traits in diverse samples. Bioinformatics 23, 2633–2635 (2007).Chang, C. C. et al. Second-generation PLINK: rising to the challenge of larger and richer datasets. Gigascience 4, 7 (2015).Team, R. C. (2015). http://www.r-project.org/ .Krzywinski, M. I. et al. Circos: an information aesthetic for comparative genomics. Genome Res. 19, 1639–1645 (2009).Kosman, E. & Leonard, K. J. Similarity coefficients for molecular markers in studies of genetic relationships between individuals for haploid, diploid, and polyploid species. Mol. Ecol. 14, 415–424 (2005).Huson, D. H. & Bryant, D. Estimating Phylogenetic Trees and Networks Using SplitsTree 4. www.splitstree.org (2005).Danecek, P. et al. The variant call format and VCFtools. Bioinformatics 27, 2156–2158 (2011).Cingolani, P. et al. A program for annotating and predicting the effects of single nucleotide polymorphisms, SnpEff: SNPs in the genome of Drosophila melanogaster strainw1118; iso-2; iso-3. Fly 6, 80–92 (2012).Wu, S. et al. A common genetic mechanism underlies morphological diversity in fruits and other plant organs. Nat. Commun. 9, 4734 (2018).Drevensek, S. et al. The Arabidopsis TRM1–TON1 interaction reveals a recruitment network common to plant cortical microtubule arrays and eukaryotic centrosomes. Plant Cell 24, 178–191 (2012).Sievers, F. et al. Fast, scalable generation of high‐quality protein multiple sequence alignments using Clustal Omega. Mol. Syst. Biol. 7, 539 (2011).Nguyen, L.-T., Schmidt, H. A., von Haeseler, A. & Minh, B. Q. IQ-TREE: a fast and effective stochastic algorithm for estimating maximum-likelihood phylogenies. Mol. Biol. Evol. 32, 268–274 (2014).Kalyaanamoorthy, S., Minh, B. Q., Wong, T. K. F., von Haeseler, A. & Jermiin, L. S. ModelFinder: fast model selection for accurate phylogenetic estimates. Nat. Methods 14, 587 (2017).Hoang, D. T., Chernomor, O., von Haeseler, A., Minh, B. Q. & Vinh, L. S. UFBoot2: improving the ultrafast bootstrap approximation. Mol. Biol. Evol. 35, 518–522 (2017).Bailey, T. L. et al. MEME SUITE: tools for motif discovery and searching. Nucleic Acids Res. 37, W202–W208 (2009).Leida, C. et al. Variability of candidate genes, genetic structure and association with sugar accumulation and climacteric behavior in a broad germplasm collection of melon (Cucumis melo L.). BMC Genet. 16, 28 (2015).Esteras, C. et al. SNP genotyping in melons: genetic variation, population structure, and linkage disequilibrium. Theor. Appl. Genet. 126, 1285–1303 (2013).Maria José Gonzalo et al. Re-evaluation of the role of Indian germplasm as center of melon diversification based on genotyping-by-sequencing analysis. BMC Genom. 20, p. 448 (2019).Nimmakayala, P. et al. Single nucleotide polymorphisms generated by genotyping by sequencing to characterize genome-wide diversity, linkage disequilibrium, and selective sweeps in cultivated watermelon. BMC Genom. 15, 767 (2014).Gonzalo, M. J. & Monforte, A. J. in Genetics and Genomics of Cucurbitaceae, Grumet, Rebecca, Katzir, Nurit, Garcia-Mas, Jordi (Eds.) 269–290 (Springer, New York, U.S.A., 2016).Pomares-Viciana, T. et al. First RNA-seq approach to study fruit set and parthenocarpy in zucchini (Cucurbita pepo L.). BMC Plant Biol. 19, 61 (2019).Lu, S. et al. The cauliflower Or gene encodes a DnaJ cysteine-rich domain-containing protein that mediates high levels of β-carotene accumulation. Plant Cell 18, 3594–3605 (2006).Jin, B., Kim, J., Jung, J., Kim, D. & Park, Y. Characterization of IQ domain gene homologs as common candidate genes for elongated fruit shape in cucurbits. Hortic. Sci. Technol. 36, 85–97 (2018).van der Knaap, E. et al. What lies beyond the eye: the molecular mechanisms regulating tomato fruit weight and shape. Front. Plant Sci. 5, 227 (2014).Xiao, H., Jiang, N., Schaffner, E., Stockinger, E. J. & Van Der Knaap, E. A retrotransposon-mediated gene duplication underlies morphological variation of tomato fruit. Science 319, 1527–1530 (2008).Dou, J. et al. Genetic mapping reveals a candidate gene (ClFS1) for fruit shape in watermelon (Citrullus lanatus L.). Theor. Appl. Genet. 131, 947–958 (2018).Pan, Y. et al. Round fruit shape in WI7239 cucumber is controlled by two interacting quantitative trait loci with one putatively encoding a tomato SUN homolog. Theor. Appl. Genet. 130, 573–586 (2017).Liu, J. et al. Banana Ovate family protein MaOFP1 and MADS-box protein MuMADS1 antagonistically regulated banana fruit ripening. PLoS ONE 10, e0123870 (2015).Liu, J. et al. Mu MADS 1 and Ma OFP 1 regulate fruit quality in a tomato ovate mutant. Plant Biotechnol. J. 16, 989–1001 (2018).Cong, B., Barrero, L. S. & Tanksley, S. D. Regulatory change in YABBY-like transcription factor led to evolution of extreme fruit size during tomato domestication. Nat. Genet. 40, 800 (2008).Huang, Z., Van Houten, J., Gonzalez, G., Xiao, H. & van der Knaap, E. Genome-wide identification, phylogeny and expression analysis of SUN, OFP and YABBY gene family in tomato. Mol. Genet. Genom. 288, 111–129 (2013).Bowman, J. L. The YABBY gene family and abaxial cell fate. Curr. Opin. Plant Biol. 3, 17–22 (2000).Liu, J., Van Eck, J., Cong, B. & Tanksley, S. D. A new class of regulatory genes underlying the cause of pear-shaped tomato fruit. Proc. Natl Acad. Sci. USA 99, 13302–13306 (2002).Tsaballa, A., Pasentsis, K., Darzentas, N. & Tsaftaris, A. S. Multiple evidence for the role of an Ovate-like gene in determining fruit shape in pepper. BMC Plant Biol. 11, 46 (2011).Wang, S., Chang, Y., Guo, J. & Chen, J. G. Arabidopsis Ovate family protein 1 is a transcriptional repressor that suppresses cell elongation. Plant J. 50, 858–872 (2007).Lazzaro, M. D., Wu, S., Snouffer, A., Wang, Y. & Van Der Knaap, E. Plant organ shapes are regulated by protein interactions and associations with microtubules. Front. Plant Sci. 9, 1766 (2018)

    Identification and genomic location of a reniform nematode (Rotylenchulus reniformis) resistance locus (Renari) introgressed from Gossypium aridum into upland cotton (G. hirsutum)

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    In this association mapping study, a tri-species hybrid, [Gossypium arboreum × (G. hirsutum × G. aridum)2], was crossed with MD51ne (G. hirsutum) and progeny from the cross were used to identify and map SSR markers associated with reniform nematode (Rotylenchulus reniformis) resistance. Seventy-six progeny (the 50 most resistant and 26 most susceptible) plants were genotyped with 104 markers. Twenty-five markers were associated with a resistance locus that we designated Renari and two markers, BNL3279_132 and BNL2662_090, mapped within 1 cM of Renari. Because the SSR fragments associated with resistance were found in G. aridum and the bridging line G 371, G. aridum is the likely source of this resistance. The resistance is simply inherited, possibly controlled by a single dominant gene. The markers identified in this project are a valuable resource to breeders and geneticists in the quest to produce cotton cultivars with a high level of resistance to reniform nematode
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