| 1. |
- Nordström, Karin, 1973-, et al.
(författare)
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Invertebrate vision : Peripheral adaptation to repeated object motion
- 2013
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Ingår i: Current Biology. - : Cell Press. - 0960-9822 .- 1879-0445. ; 23:15, s. R655-R656
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Visual systems adapt rapidly to objects moving repeatedly within the visual field, because such objects are likely irrelevant. In the crab, the neural switch for such adaptation has been found to take place at a surprisingly early stage of the visual processing pathway.
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| 2. |
- Smolka, Jochen, et al.
(författare)
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A new galloping gait in an insect
- 2013
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Ingår i: Current Biology. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 23:20, s. 913-915
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Tidskriftsartikel (refereegranskat)abstract
- An estimated three million insect species all walk using variations of the alternating tripod gait. At any one time, these animals hold one stable triangle of legs steady while swinging the opposite triangle forward. Here, we report the discovery that three different flightless desert dung beetles use an additional gallop-like gait, which has never been described in any insect before. Like a bounding hare, the beetles propel their body forward by synchronously stepping with both middle legs and then both front legs. Surprisingly, this peculiar galloping gait delivers lower speeds than the alternating tripod gait. Why these beetles have shifted so radically away from the most widely used walking style on our planet is as yet unknown.
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| 3. |
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| 4. |
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| 5. |
- Budd, Graham E.
(författare)
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Animal Evolution : Trilobites on Speed
- 2013
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 23:19, s. R878-R880
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Chardon, Fabien, et al.
(författare)
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Leaf Fructose Content Is Controlled by the Vacuolar Transporter SWEET17 in Arabidopsis
- 2013
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 23:8, s. 697-702
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Tidskriftsartikel (refereegranskat)abstract
- In higher plants, soluble sugars are mainly present as sucrose, glucose, and fructose [1]. Sugar allocation is based on both source-to-sink transport and intracellular transport between the different organelles [2,3] and depends on actual plant requirements [4]. Under abiotic stress conditions, such as nitrogen limitation, carbohydrates accumulate in plant cells [5]. Despite an increasing number of genetic studies [6, 7], the genetic architecture determining carbohydrate composition is poorly known. Using a quantitative genetics approach, we determined that the carrier protein SWEET17 is a major factor controlling fructose content in Arabidopsis leaves. We observed that when SWEET17 expression is reduced, either by induced or natural variation, fructose accumulates in leaves, suggesting an enhanced storage capacity. Subcellular localization of SWEET17-GFP to the tonoplast and functional expression in Xenopus oocytes showed that SWEET17 is the first vacuolar fructose transporter to be characterized in plants. Physiological studies in planta provide evidence that SWEET17 acts to export fructose out of the vacuole. Overall, our results suggest that natural variation in leaf fructose levels is controlled by the vacuolar fructose transporter SWEET17. SWEET17 is highly conserved across the plant kingdom; thus, these findings offer future possibilities to modify carbohydrate partitioning in crops.
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| 7. |
- Dacke, Marie, et al.
(författare)
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Dung Beetles Use the Milky Way for Orientation
- 2013
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Ingår i: Current Biology. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 23:4, s. 298-300
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Tidskriftsartikel (refereegranskat)abstract
- When the moon is absent from the night sky, stars remain as celestial visual cues. Nonetheless, only birds [1, 2], seals [3], and humans [4] are known to use stars for orientation. African ball-rolling dung beetles exploit the sun, the moon, and the celestial polarization pattern to move along straight paths, away from the intense competition at the dung pile [5-9]. Even on clear moonless nights, many beetles still manage to orientate along straight paths [5]. This led us to hypothesize that dung beetles exploit the starry sky for orientation, a feat that has, to our knowledge, never been demonstrated in an insect. Here, we show that dung beetles transport their dung balls along straight paths under a starlit sky but lose this ability under overcast conditions. In a planetarium, the beetles orientate equally well when rolling under a full starlit sky as when only the Milky Way is present. The use of this bidirectional celestial cue for orientation has been proposed for vertebrates [10], spiders [11], and insects [5, 12], but never proven. This finding represents the first convincing demonstration for the use of the starry sky for orientation in insects and provides the first documented use of the Milky Way for orientation in the animal kingdom.
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| 8. |
- Fernius, Josefin, et al.
(författare)
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Cohesin-dependent association of scc2/4 with the centromere initiates pericentromeric cohesion establishment
- 2013
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Ingår i: Current Biology. - : Cell Press. - 0960-9822 .- 1879-0445. ; 23:7, s. 599-606
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Tidskriftsartikel (refereegranskat)abstract
- Cohesin is a conserved ring-shaped multiprotein complex that participates in chromosome segregation, DNA repair, and transcriptional regulation [1, 2]. Cohesin loading onto chromosomes universally requires the Scc2/4 "loader" complex (also called NippedBL/Mau2), mutations in which cause the developmental disorder Cornelia de Lange syndrome in humans [1-9]. Cohesin is most concentrated in the pericentromere, the region surrounding the centromere [10-15]. Enriched pericentromeric cohesin requires the Ctf19 kinetochore subcomplex in budding yeast [16-18]. Here, we uncover the spatial and temporal determinants for Scc2/4 centromere association. We demonstrate that the critical role of the Ctf19 complex is to enable Scc2/4 association with centromeres, through which cohesin loads and spreads onto the adjacent pericentromere. We show that, unexpectedly, Scc2 association with centromeres depends on cohesin itself. The absence of the Scc1/Mcd1/Rad21 cohesin subunit precludes Scc2 association with centromeres from anaphase until late G1. Expression of SCC1 is both necessary and sufficient for the binding of cohesin to its loader, the association of Scc2 with centromeres, and cohesin loading. We propose that cohesin triggers its own loading by enabling Scc2/4 to connect with chromosomal landmarks, which at centromeres are specified by the Ctf19 complex. Overall, our findings provide a paradigm for the spatial and temporal control of cohesin loading.
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| 9. |
- Fillinger, L., et al.
(författare)
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Rapid Glass Sponge Expansion after Climate-Induced Antarctic Ice Shelf Collapse
- 2013
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822. ; 23:14, s. 1330-1334
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Tidskriftsartikel (refereegranskat)abstract
- Over 30% of the Antarctic continental shelf is permanently covered by floating ice shelves [1], providing aphotic conditions [2, 3] for a depauperate fauna sustained by laterally advected food [4, 5]. In much of the remaining Antarctic shallows (<300 m depth), seasonal sea-ice melting allows a patchy primary production supporting rich megabenthic communities [6, 7] dominated by glass sponges (Porifera, Hexactinellida) [8-10]. The catastrophic collapse of ice shelves due to rapid regional warming along the Antarctic Peninsula in recent decades [11] has exposed over 23,000 km(2) of seafloor to local primary production [12]. The response of the benthos to this unprecedented flux of food [13] is, however, still unknown. In 2007, 12 years after disintegration of the Larsen A ice shelf, a first biological survey interpreted the presence of hexactinellids as remnants of a former under-ice fauna with deep-sea characteristics [14]. Four years later, we revisited the original transect, finding 2- and 3-fold increases in glass sponge biomass and abundance, respectively, after only two favorable growth periods. Our findings, along with other long-term studies [15], suggest that Antarctic hexactinellids, locked in arrested growth for decades [8, 16], may undergo boom-and-bust cycles, allowing them to quickly colonize new habitats. The cues triggering growth and reproduction in Antarctic glass sponges remain enigmatic.
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| 10. |
- Fisher, Roberta M., et al.
(författare)
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Group Formation, Relatedness, and the Evolution of Multicellularity
- 2013
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Ingår i: Current Biology. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 23:12, s. 1120-1125
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of multicellular organisms represents one of approximately eight major evolutionary transitions that have occurred on earth [1-4]. The major challenge raised by this transition is to explain why single cells should join together and become mutually dependent, in a way that leads to a more complex multicellular life form that can only replicate as a whole. It has been argued that a high genetic relatedness (r) between cells played a pivotal role in the evolutionary transition from single-celled to multicellular organisms, because it leads to reduced conflict and an alignment of interests between cells [1-17]. We tested this hypothesis with a comparative study, comparing the form of multicellularity in species where groups are clonal (r = 1) to species where groups are potentially nonclonal (r <= 1). We found that species with clonal group formation were more likely to have undergone the major evolutionary transition to obligate multicellularity and had more cell types, a higher likelihood of sterile cells, and a trend toward higher numbers of cells in a group. More generally, our results unify the role of group formation and genetic relatedness across multiple evolutionary transitions and provide an unmistakable footprint of how natural selection has shaped the evolution of life [1].
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