| 361. |
- Hantke, Max F., et al.
(författare)
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High-throughput imaging of heterogeneous cell organelles with an X-ray laser
- 2014
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Ingår i: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 8:12, s. 943-949
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Tidskriftsartikel (refereegranskat)abstract
- We overcome two of the most daunting challenges in single-particle diffractive imaging: collecting many high-quality diffraction patterns on a small amount of sample and separating components from mixed samples. We demonstrate this on carboxysomes, which are polyhedral cell organelles that vary in size and facilitate up to 40% of Earth's carbon fixation. A new aerosol sample-injector allowed us to record 70,000 low-noise diffraction patterns in 12 min with the Linac Coherent Light Source running at 120 Hz. We separate different structures directly from the diffraction data and show that the size distribution is preserved during sample delivery. We automate phase retrieval and avoid reconstruction artefacts caused by missing modes. We attain the highest-resolution reconstructions on the smallest single biological objects imaged with an X-ray laser to date. These advances lay the foundations for accurate, high-throughput structure determination by flash-diffractive imaging and offer a means to study structure and structural heterogeneity in biology and elsewhere.
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| 362. |
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| 363. |
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| 364. |
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| 365. |
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| 366. |
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| 367. |
- Hartmann, A, et al.
(författare)
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Tourette syndrome research highlights from 2021
- 2022
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Ingår i: F1000Research. - : F1000 Research Ltd. - 2046-1402. ; 11, s. 716-
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Tidskriftsartikel (refereegranskat)abstract
- We summarize selected research reports from 2021 relevant to Tourette syndrome that the authors consider most important or interesting. The authors welcome article suggestions and thoughtful feedback from readers.
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| 368. |
- Hartmann, Fanny E., et al.
(författare)
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Size Variation of the Nonrecombining Region on the Mating-Type Chromosomes in the Fungal Podospora anserina Species Complex
- 2021
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Ingår i: Molecular biology and evolution. - : Oxford University Press. - 0737-4038 .- 1537-1719. ; 38:6, s. 2475-2492
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Tidskriftsartikel (refereegranskat)abstract
- Sex chromosomes often carry large nonrecombining regions that can extend progressively over time, generating evolutionary strata of sequence divergence. However, some sex chromosomes display an incomplete suppression of recombination. Large genomic regions without recombination and evolutionary strata have also been documented around fungal mating-type loci, but have been studied in only a few fungal systems. In the model fungus Podospora anserina (Ascomycota, Sordariomycetes), the reference S strain lacks recombination across a 0.8-Mb region around the mating-type locus. The lack of recombination in this region ensures that nuclei of opposite mating types are packaged into a single ascospore (pseudohomothallic lifecycle). We found evidence for a lack of recombination around the mating-type locus in the genomes of ten P. anserina strains and six closely related pseudohomothallic Podospora species. Importantly, the size of the nonrecombining region differed between strains and species, as indicated by the heterozygosity levels around the mating-type locus and experimental selfing. The nonrecombining region is probably labile and polymorphic, differing in size and precise location within and between species, resulting in occasional, but infrequent, recombination at a given base pair. This view is also supported by the low divergence between mating types, and the lack of strong linkage disequilibrium, chromosomal rearrangements, transspecific polymorphism and genomic degeneration. We found a pattern suggestive of evolutionary strata in P. pseudocomata. The observed heterozygosity levels indicate low but nonnull outcrossing rates in nature in these pseudohomothallic fungi. This study adds to our understanding of mating-type chromosome evolution and its relationship to mating systems.
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| 369. |
- Hartmann, Henrik, et al.
(författare)
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Climate Change Risks to Global Forest Health : Emergence of Unexpected Events of Elevated Tree Mortality Worldwide
- 2022
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Ingår i: Annual Review of Plant Biology. - : Annual Reviews. - 1543-5008 .- 1545-2123. ; 73, s. 673-702
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Forskningsöversikt (refereegranskat)abstract
- Recent observations of elevated tree mortality following climate extremes, like heat and drought, raise concerns about climate change risks to global forest health. We currently lack both sufficient data and understanding to identify whether these observations represent a global trend toward increasing tree mortality. Here, we document events of sudden and unexpected elevated tree mortality following heat and drought events in ecosystems that previously were considered tolerant or not at risk of exposure. These events underscore the fact that climate change may affect forests with unexpected force in the future. We use the events as examples to highlight current difficulties and challenges for realistically predicting such tree mortality events and the uncertainties about future forest condition. Advances in remote sensing technology and greater availably of high-resolution data, from both field assessments and satellites, are needed to improve both understanding and prediction of forest responses to future climate change.
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| 370. |
- Hartmann, Michael, et al.
(författare)
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Increasing robustness and sensitivity of protein microarrays through microagitation and automation
- 2006
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 564:1, s. 66-73
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Tidskriftsartikel (refereegranskat)abstract
- Assay systems that employ protein microarrays for the analysis of complex samples are powerful tools to generate a high amount of data from a limiting amount of sample. Due to miniaturization, these systems are susceptible to fluctuations during signal generation and the use of uniform conditions for sample incubation and during the assay procedure is required to get reproducible results. Diffusion limits may prevent constant conditions on all parts of the array and can lead to the decease of the sensitivity of the array. Therefore, we set-up an automated assay system integrating a novel microagitation device using surface acoustic wave (SAW) technology. Multiplexed assays for the detection of autoantibodies from human serum and sandwich immunoassay for the detection of matrix metalloproteases (MMPs) were used to evaluate the system. Diffusion-rate limited solid phase reactions were enhanced by microagitation using the SAW technology resulting in up to three-fold higher signals.
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