35 research outputs found
A semi-automated approach for GIS based generation of topographic attributes for landform classification
This paper presents LANDFORM, a customized GIS application for semi-automated classification of landform elements, based on landscape parameters. Using custom commands, topographic attributes like curvature or elevation percentile were derived from a Digital Elevation Model (DEM) and used as thresholds for the classification of Crests, Flats, Depressions and Simple Slopes. With a new method, Simple Slopes were further subdivided in Upper, Mid and Lower Slopes at significant breakpoints along slope profiles. The paper discusses the results of a fuzzy set algorithm that was used to compare the similarity between the map generated by LANDFORM and the visual photo- interpretation conducted by a soil expert over the same area. The classification results can be used in applications related to precision agriculture, land degradation studies, and spatial modelling applications where landform is identified as an influential factor in the processes under study
TRAIP promotes DNA damage response during genome replication and is mutated in primordial dwarfism.
DNA lesions encountered by replicative polymerases threaten genome stability and cell cycle progression. Here we report the identification of mutations in TRAIP, encoding an E3 RING ubiquitin ligase, in patients with microcephalic primordial dwarfism. We establish that TRAIP relocalizes to sites of DNA damage, where it is required for optimal phosphorylation of H2AX and RPA2 during S-phase in response to ultraviolet (UV) irradiation, as well as fork progression through UV-induced DNA lesions. TRAIP is necessary for efficient cell cycle progression and mutations in TRAIP therefore limit cellular proliferation, providing a potential mechanism for microcephaly and dwarfism phenotypes. Human genetics thus identifies TRAIP as a component of the DNA damage response to replication-blocking DNA lesions.This work was supported by funding from the Medical Research Council and the European Research Council (ERC, 281847) (A.P.J.), the Lister Institute for Preventative Medicine (A.P.J. and G.S.S.), Medical Research Scotland (L.S.B.), German Federal Ministry of Education and Research (BMBF, 01GM1404) and E-RARE network EuroMicro (B.W), Wellcome Trust (M. Hurles), CMMC (P.N.), Cancer Research UK (C17183/A13030) (G.S.S. and M.R.H), Swiss National Science Foundation (P2ZHP3_158709) (O.M.), AIRC (12710) and ERC/EU FP7 (CIG_303806) (S.S.), Cancer Research UK (C6/A11224) and ERC/EU FP7 (HEALTH-F2- 2010-259893) (A.N.B. and S.P.J.).This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/ng.345
Meier-Gorlin syndrome
Meier-Gorlin syndrome (MGS) is a rare autosomal recessive primordial dwarfism disorder, characterized by microtia, patellar applasia/hypoplasia, and a proportionate short stature. Associated clinical features encompass feeding problems, congenital pulmonary emphysema, mammary hypoplasia in females and urogenital anomalies, such as cryptorchidism and hypoplastic labia minora and majora. Typical facial characteristics during childhood comprise a small mouth with full lips and micro-retrognathia. During ageing, a narrow, convex nose becomes more prominent. The diagnosis MGS should be considered in patients with at least two of the three features of the clinical triad of microtia, patellar anomalies, and pre- and postnatal growth retardation. In patients with short stature and/or microtia, the patellae should be assessed with care by ultrasonography before age 6 or radiography thereafter. Mutations in one of five genes (ORC1, ORC4, ORC6, CDT1, and CDC6) of the pre-replication complex, involved in DNA-replication, are detected in approximately 67-78 % of patients with MGS. Patients with ORC1 and ORC4 mutations appear to have the most severe short stature and microcephaly. Management should be directed towards in-depth investigation, treatment and prevention of associated problems, such as growth retardation, feeding problems, hearing loss, luxating patellae, knee pain, gonarthrosis, and possible pulmonary complications due to congenital pulmonary emphysema with or without broncho- or laryngomalacia. Growth hormone treatment is ineffective in most patients with MGS, but may be effective in patients in whom growth continues to decrease after the first year of life (usually growth velocity normalizes after the first year) and with low levels of IGF1. At present, few data is available about reproduction of females with MGS, but the risk of premature labor might be increased. Here, we propose experience-based guidelines for the regular care and treatment of MGS patients
Mutations in CDC45, Encoding an Essential Component of the Pre-initiation Complex, Cause Meier-Gorlin Syndrome and Craniosynostosis
DNA replication precisely duplicates the genome to ensure stable inheritance of genetic information. Impaired licensing of origins of replication during the G1 phase of the cell cycle has been implicated in Meier-Gorlin syndrome (MGS), a disorder defined by the triad of short stature, microtia, and a/hypoplastic patellae. Biallelic partial loss-of-function mutations in multiple components of the pre-replication complex (preRC; ORC1, ORC4, ORC6, CDT1, or CDC6) as well as de novo stabilizing mutations in the licensing inhibitor, GMNN, cause MGS. Here we report the identification of mutations in CDC45 in 15 affected individuals from 12 families with MGS and/or craniosynostosis. CDC45 encodes a component of both the pre-initiation (preIC) and CMG helicase complexes, required for initiation of DNA replication origin firing and ongoing DNA synthesis during S-phase itself, respectively, and hence is functionally distinct from previously identified MGS-associated genes. The phenotypes of affected individuals range from syndromic coronal craniosynostosis to severe growth restriction, fulfilling diagnostic criteria for Meier-Gorlin syndrome. All mutations identified were biallelic and included synonymous mutations altering splicing of physiological CDC45 transcripts, as well as amino acid substitutions expected to result in partial loss of function. Functionally, mutations reduce levels of full-length transcripts and protein in subject cells, consistent with partial loss of CDC45 function and a predicted limited rate of DNA replication and cell proliferation. Our findings therefore implicate the preIC as an additional protein complex involved in the etiology of MGS and connect the core cellular machinery of genome replication with growth, chondrogenesis, and cranial suture homeostasis
Mutations in DONSON disrupt replication fork stability and cause microcephalic dwarfism
To ensure efficient genome duplication, cells have evolved numerous factors that promote unperturbed DNA replication and protect, repair and restart damaged forks. Here we identify downstream neighbor of SON (DONSON) as a novel fork protection factor and report biallelic DONSON mutations in 29 individuals with microcephalic dwarfism. We demonstrate that DONSON is a replisome component that stabilizes forks during genome replication. Loss of DONSON leads to severe replication-associated DNA damage arising from nucleolytic cleavage of stalled replication forks. Furthermore, ATM- and Rad3-related (ATR)-dependent signaling in response to replication stress is impaired in DONSON-deficient cells, resulting in decreased checkpoint activity and the potentiation of chromosomal instability. Hypomorphic mutations in DONSON substantially reduce DONSON protein levels and impair fork stability in cells from patients, consistent with defective DNA replication underlying the disease phenotype. In summary, we have identified mutations in DONSON as a common cause of microcephalic dwarfism and established DONSON as a critical replication fork protein required for mammalian DNA replication and genome stability
Geomorphometric Landscape Analysis of Agricultural Areas and Rangelands of Western Australia
Several techniques exist for generating landform units and these differ in terms of their categorical structure. The geopedologic approach to landform classification is based on a strong integration of geomorphology and pedology using geomorphology as a tool to improve and speed up soil mapping. Likewise, the Australian classification of landforms proposes a two-level descriptive procedure for a systematic, parametric description of landforms into landform patterns and landform elements. This chapter examines geopedology in the context of soil-landscape studies in Australia, and discusses two case studies from Western Australia, where GIS-based geomorphometric tools were used for semi-automated classification of landform elements, based on topographic attributes like slope, curvature or elevation percentile. The case studies illustrate how results of the geomorphic classification add value to management decisions related to rangelands, precision agriculture, spatial analysis, and modelling of land degradation, and other spatial modelling applications where landscape morphometry is an influential factor in the processes under study
Survey Accuracy Analysis of a Hand-held Mobile LiDAR Device for Cultural Heritage Documentation
In this paper, the survey accuracy of a hand-held, GNSS-free mobile LiDAR device, the Zebedee, is studied by collecting measurements of several different geometric features in four different datasets. We use a new comprehensive accuracy assessment methodology based on geometric modelling which involves a geometric model of a prism/ pyramid for square structure. The point cloud accuracies of the features (planes, cylinders, catenaries, prisms and pyramids) were compared to that of a conventional survey-grade LiDAR system, the Leica ScanStation C10. The results suggested that the Zebedee accuracy is very comparable to the C10. For instance, the mean RMS error of plane fittings for the Zebedee is approximately 1.1 cm versus 0.6 cm for the C10. The estimated cylinder radii between the Zebedee and the C10 has only 1.4% difference in average, while the radii difference in prism/pyramid fitting is only 0.8%. As a result, the Zebedee LiDAR device is suitable for heritage mapping not only because it has high operation flexibility but also desired high accuracy
Differential and overlapping functions of two closely related Drosophila FGF8-like growth factors in mesoderm development
Thisbe (Ths) and Pyramus (Pyr), two closely related Drosophila
homologues of the vertebrate fibroblast growth factor (FGF) 8/17/18 subfamily,
are ligands for the FGF receptor Heartless (Htl). Both ligands are required
for mesoderm development, but their differential expression patterns suggest
distinct functions during development. We generated single mutants and found
that ths or pyr loss-of-function mutations are semi-lethal
and mutants exhibit much weaker phenotypes as compared with loss of both
ligands or htl. Thus, pyr and ths display partial
redundancy in their requirement in embryogenesis and viability. Nevertheless,
we find that pyr and ths single mutants display defects in
gastrulation and mesoderm differentiation. We show that localised expression
of pyr is required for normal cell protrusions and high levels of
MAPK activation in migrating mesoderm cells. The results support the model
that Pyr acts as an instructive cue for mesoderm migration during
gastrulation. Consistent with this function, mutations in pyr affect
the normal segmental number of cardioblasts. Furthermore, Pyr is essential for
the specification of even-skipped-positive mesodermal precursors and
Pyr and Ths are both required for the specification of a subset of somatic
muscles. The results demonstrate both independent and overlapping functions of
two FGF8 homologues in mesoderm morphogenesis and differentiation. We propose
that the integration of Pyr and Ths function is required for robustness of
Htl-dependent mesoderm spreading and differentiation, but that the functions
of Pyr have become more specific, possibly representing an early stage of
functional divergence after gene duplication of a common ancestor