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| 2. |
- Antonelli, Alexandre, 1978, et al.
(author)
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Madagascar's extraordinary biodiversity : Evolution, distribution, and use
- 2022
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 378:6623, s. 962-
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Journal article (peer-reviewed)abstract
- Madagascar's biota is hyperdiverse and includes exceptional levels of endemicity. We review the current state of knowledge on Madagascar's past and current terrestrial and freshwater biodiversity by compiling and presenting comprehensive data on species diversity, endemism, and rates of species description and human uses, in addition to presenting an updated and simplified map of vegetation types. We report a substantial increase of records and species new to science in recent years; however, the diversity and evolution of many groups remain practically unknown (e.g., fungi and most invertebrates). Digitization efforts are increasing the resolution of species richness patterns and we highlight the crucial role of field- and collections-based research for advancing biodiversity knowledge and identifying gaps in our understanding, particularly as species richness corresponds closely to collection effort. Phylogenetic diversity patterns mirror that of species richness and endemism in most of the analyzed groups. We highlight humid forests as centers of diversity and endemism because of their role as refugia and centers of recent and rapid radiations. However, the distinct endemism of other areas, such as the grassland-woodland mosaic of the Central Highlands and the spiny forest of the southwest, is also biologically important despite lower species richness. The documented uses of Malagasy biodiversity are manifold, with much potential for the uncovering of new useful traits for food, medicine, and climate mitigation. The data presented here showcase Madagascar as a unique " living laboratory" for our understanding of evolution and the complex interactions between people and nature. The gathering and analysis of biodiversity data must continue and accelerate if we are to fully understand and safeguard this unique subset of Earth's biodiversity.
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| 3. |
- Aspholm-Hurtig, Marina, et al.
(author)
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Functional adaptation of BabA, the H. pylori ABO blood group antigen binding adhesin.
- 2004
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In: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 305:5683, s. 519-22
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Journal article (peer-reviewed)abstract
- Adherence by Helicobacter pylori increases the risk of gastric disease. Here, we report that more than 95% of strains that bind fucosylated blood group antigen bind A, B, and O antigens (generalists), whereas 60% of adherent South American Amerindian strains bind blood group O antigens best (specialists). This specialization coincides with the unique predominance of blood group O in these Amerindians. Strains differed about 1500-fold in binding affinities, and diversifying selection was evident in babA sequences. We propose that cycles of selection for increased and decreased bacterial adherence contribute to babA diversity and that these cycles have led to gradual replacement of generalist binding by specialist binding in blood group O-dominant human populations.
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| 4. |
- Björk, Glenn R, et al.
(author)
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Prevention of translational frameshifting by the modified nucleoside 1-methylguanosine
- 1989
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In: Science. - 0036-8075 .- 1095-9203. ; 244:4907, s. 986-989
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Journal article (peer-reviewed)abstract
- The methylated nucleoside 1-methylguanosine (m1G) is present next to the 3' end of the anticodon (position 37) in all transfer RNAs (tRNAs) that read codons starting with C except in those tRNAs that read CAN codons. All of the three proline tRNA species, which read CCN codons in Salmonella typhimurium, have been sequenced and shown to contain m1G in position 37. A mutant of S. typhimurium that lacks m1G in its tRNA when grown at temperatures above 37 degrees C, has now been isolated. The mutation (trmD3) responsible for this methylation deficiency is in the structural gene (trmD) for the tRNA(m1G37)methyltransferase. Therefore, the three proline tRNAs in the trmD3 mutant have an unmodified guanosine at position 37. Furthermore, the trmD3 mutation also causes at least one of the tRNAPro species to frequently shift frame when C's are present successively in the message. Thus, m1G appears to prevent frameshifting. The data from eubacteria apply to both eukaryotes and archaebacteria.
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| 5. |
- Brigham-Grette, Julie, et al.
(author)
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Pliocene warmth, polar amplification, and stepped pleistocene cooling recorded in NE arctic russia
- 2013
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In: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 340:6139, s. 1421-1427
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Journal article (peer-reviewed)abstract
- Understanding the evolution of Arctic polar climate from the protracted warmth of the middle Pliocene into the earliest glacial cycles in the Northern Hemisphere has been hindered by the lack of continuous, highly resolved Arctic time series. Evidence from Lake El'gygytgyn, in northeast (NE) Arctic Russia, shows that 3.6 to 3.4 million years ago, summer temperatures were similar to 8 degrees C warmer than today, when the partial pressure of CO2 was similar to 400 parts per million. Multiproxy evidence suggests extreme warmth and polar amplification during the middle Pliocene, sudden stepped cooling events during the Pliocene-Pleistocene transition, and warmer than present Arctic summers until similar to 2.2 million years ago, after the onset of Northern Hemispheric glaciation. Our data are consistent with sea-level records and other proxies indicating that Arctic cooling was insufficient to support large-scale ice sheets until the early Pleistocene.
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| 6. |
- Brodin, Tomas, et al.
(author)
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Dilute concentrations of a psychiatric drug alter behavior of fish from natural populations
- 2013
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In: Science. - : The American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 339:6121, s. 814-815
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Journal article (peer-reviewed)abstract
- Environmental pollution by pharmaceuticals is increasingly recognized as a major threat to aquatic ecosystems worldwide. A variety of pharmaceuticals enter waterways by way of treated wastewater effluents and remain biochemically active in aquatic systems. Several ecotoxicological studies have been done, but generally, little is known about the ecological effects of pharmaceuticals. Here we show that a benzodiazepine anxiolytic drug (oxazepam) alters behavior and feeding rate of wild European perch (Perca fluviatilis) at concentrations encountered in effluent-influenced surface waters. Individuals exposed to water with dilute drug concentrations (1.8 micrograms liter–1) exhibited increased activity, reduced sociality, and higher feeding rate. As such, our results show that anxiolytic drugs in surface waters alter animal behaviors that are known to have ecological and evolutionary consequences.
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| 7. |
- Bäckman, Lars, et al.
(author)
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Effects of working-memory training on striatal dopamine release
- 2011
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 333:6043, s. 718-
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Journal article (peer-reviewed)abstract
- Updating of working memory has been associated with striato-frontal brain regions and phasic dopaminergic neurotransmission. We assessed raclopride binding to striatal dopamine (DA) D2 receptors during a letter-updating task and a control condition before and after 5 weeks of updating training. Results showed that updating affected DA activity before training and that training further increased striatal DA release during updating. These findings highlight the pivotal role of transient neural processes associated with D2 receptor activity in working memory.
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| 8. |
- Böhlenius, Henrik, et al.
(author)
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CO/FT regulatory module controls timing of flowering and seasonal growth cessation in trees.
- 2006
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In: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 312:5776, s. 1040-3
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Journal article (peer-reviewed)abstract
- Forest trees display a perennial growth behavior characterized by a multiple-year delay in flowering and, in temperate regions, an annual cycling between growth and dormancy. We show here that the CO/FT regulatory module, which controls flowering time in response to variations in daylength in annual plants, controls flowering in aspen trees. Unexpectedly, however, it also controls the short-day–induced growth cessation and bud set occurring in the fall. This regulatory mechanism can explain the ecogenetic variation in a highly adaptive trait: the critical daylength for growth cessation displayed by aspen trees sampled across a latitudinal gradient spanning northern Europe.
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| 9. |
- Dahlin, Erika, 1981-, et al.
(author)
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Transfer of learning after updating training mediated by the striatum
- 2008
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 320:5882, s. 1510-1512
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Journal article (peer-reviewed)abstract
- Process-specific training can improve performance on untrained tasks, but the magnitude of gain is variable and often there is no transfer at all. We demonstrate transfer to a 3-back test of working memory after 5 weeks of training in updating. The transfer effect was based on a joint training-related activity increase for the criterion (letter memory) and transfer tasks in a striatal region that also was recruited pretraining. No transfer was observed to a task that did not engage updating and striatal regions, and age-related striatal changes imposed constraints on transfer. These findings indicate that transfer can occur if the criterion and transfer tasks engage specific overlapping processing components and brain regions.
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| 10. |
- Doudna, Jennifer A., et al.
(author)
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The new frontier of genome engineering with CRISPR-Cas9
- 2014
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346:6213, s. 1077-
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Research review (peer-reviewed)abstract
- The advent of facile genome engineering using the bacterial RNA-guided CRISPR-Cas9 system in animals and plants is transforming biology. We review the history of CRISPR (clustered regularly interspaced palindromic repeat) biology from its initial discovery through the elucidation of the CRISPR-Cas9 enzyme mechanism, which has set the stage for remarkable developments using this technology to modify, regulate, or mark genomic loci in a wide variety of cells and organisms from all three domains of life. These results highlight a new era in which genomic manipulation is no longer a bottleneck to experiments, paving the way toward fundamental discoveries in biology, with applications in all branches of biotechnology, as well as strategies for human therapeutics.
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