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| 12. |
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| 13. |
- Haas, Brian J., et al.
(author)
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Genome sequence and analysis of the Irish potato famine pathogen Phytophthora infestans
- 2009
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 461:7262, s. 393-398
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Journal article (peer-reviewed)abstract
- Phytophthora infestans is the most destructive pathogen of potato and a model organism for the oomycetes, a distinct lineage of fungus-like eukaryotes that are related to organisms such as brown algae and diatoms. As the agent of the Irish potato famine in the mid-nineteenth century, P. infestans has had a tremendous effect on human history, resulting in famine and population displacement(1). To this day, it affects world agriculture by causing the most destructive disease of potato, the fourth largest food crop and a critical alternative to the major cereal crops for feeding the world's population(1). Current annual worldwide potato crop losses due to late blight are conservatively estimated at $6.7 billion(2). Management of this devastating pathogen is challenged by its remarkable speed of adaptation to control strategies such as genetically resistant cultivars(3,4). Here we report the sequence of the P. infestans genome, which at similar to 240 megabases (Mb) is by far the largest and most complex genome sequenced so far in the chromalveolates. Its expansion results from a proliferation of repetitive DNA accounting for similar to 74% of the genome. Comparison with two other Phytophthora genomes showed rapid turnover and extensive expansion of specific families of secreted disease effector proteins, including many genes that are induced during infection or are predicted to have activities that alter host physiology. These fast-evolving effector genes are localized to highly dynamic and expanded regions of the P. infestans genome. This probably plays a crucial part in the rapid adaptability of the pathogen to host plants and underpins its evolutionary potential.
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| 14. |
- Johnsen, S, et al.
(author)
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Crepuscular and nocturnal illumination and its effects on color perception by the nocturnal hawkmoth Deilephila elpenor
- 2006
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In: Journal of Experimental Biology. - : The Company of Biologists. - 1477-9145 .- 0022-0949. ; 209:5, s. 789-800
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Journal article (peer-reviewed)abstract
- Recent studies have shown that certain nocturnal insect and vertebrate species have true color vision under nocturnal illumination. Thus, their vision is potentially affected by changes in the spectral quality of twilight and nocturnal illumination, due to the presence or absence of the moon, artificial light pollution and other factors. We investigated this in the following manner. First we measured the spectral irradiance (from 300 to 700 nm) during the day, sunset, twilight, full moon, new moon, and in the presence of high levels of light pollution. The spectra were then converted to both human-based chromaticities and to relative quantum catches for the nocturnal hawkmoth Dedephila elpenor, which has color vision. The reflectance spectra of various flowers and leaves and the red hindwings of D. elpenor were also converted to chromaticities and relative quantum catches. Finally, the achromatic and chromatic contrasts (with and without von Kries color constancy) of the flowers and hindwings against a leaf background were determined under the various lighting environments. The twilight and nocturnal illuminants; were substantially different from each other, resulting in significantly different contrasts. The addition of von Kries color constancy significantly reduced the effect of changing illuminants; on chromatic contrast, suggesting that, even in this light-limited environment, the ability of color vision to provide reliable signals under changing illuminants; may offset the concurrent threefold decrease in sensitivity and spatial resolution. Given this, color vision may be more common in crepuscular and nocturnal species than previously considered.
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| 15. |
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| 16. |
- Munoz-Alarcon, Andres, et al.
(author)
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Characterization of lamin mutation phenotypes in Drosophila and comparison to human laminopathies
- 2007
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 2:6, s. e532-
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Journal article (peer-reviewed)abstract
- Lamins are intermediate filament proteins that make up the nuclear lamina, a matrix underlying the nuclear membrane in all metazoan cells that is important for nuclear form and function. Vertebrate A-type lamins are expressed in differentiating cells, while B-type lamins are expressed ubiquitously. Drosophila has two lamin genes that are expressed in A- and B-type patterns, and it is assumed that similarly expressed lamins perform similar functions. However, Drosophila and vertebrate lamins are not orthologous, and their expression patterns evolved independently. It is therefore of interest to examine the effects of mutations in lamin genes. Mutations in the mammalian lamin A/C gene cause a range of diseases, collectively called laminopathies, that include muscular dystrophies and premature aging disorders. We compared the sequences of lamin genes from different species, and we have characterized larval and adult phenotypes in Drosophila bearing mutations in the lam gene that is expressed in the B-type pattern. Larvae move less and show subtle muscle defects, and surviving lam adults are flightless and walk like aged wild-type flies, suggesting that lam phenotypes might result from neuromuscular defects, premature aging, or both. The resemblance of Drosophila lam phenotypes to human laminopathies suggests that some lamin functions may be performed by differently expressed genes in flies and mammals. Such still-unknown functions thus would not be dependent on lamin gene expression pattern, suggesting the presence of other lamin functions that are expression dependent. Our results illustrate a complex interplay between lamin gene expression and function through evolution.
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| 17. |
- Palma, Carlos-Andres, et al.
(author)
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Tailoring Bicomponent Supramolecular Nanoporous Networks : Phase Segregation, Polymorphism, and Glasses at the Solid−Liquid Interface
- 2009
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In: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 131:36, s. 13062-13071
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Journal article (peer-reviewed)abstract
- We study the formation of four supramolecular bicomponent networks based on four linear modules (linkers) bridging melamine via triple hydrogen-bonds. We explore at the nanoscale level the phenomena of polymorphism and phase segregation which rule the generation of highly crystalline nanoporous patterns self-assembled at the solid-liquid interface. The investigated linkers include two systems exposing diuracil groups in the R and ω position, naphthalene tetracarboxylic diimide and pyromellitic diimide. In situ scanning tunneling microscopy (STM) investigations revealed that, when blended with melamine, out of the four systems, three are able to form two-dimensional (2D) porous architectures, two of which exhibit highly ordered hexagonal structures, while pyromellitic diimide assembles only into one- dimensional (1D) supramolecular arrays. These bicomponent self-assembled monolayers are used as a test bed to gain detailed insight into phase segregation and polymorphism in 2D supramolecular systems by exploring the contribution of hydrogen-bond energy and periodicity, molecular flexibility, concentration and ratio of the components in solution as well as the effect of annealing via time-dependent and temperature-modulated experiments. These comparative studies, obtained through a joint experimental and computational analysis, offer new insights into strategies toward the bottom-up fabrication of highly ordered tunable nanopatterning at interfaces mediated by hydrogen bonds.
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