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- Weinstock, Joshua S, et al.
(author)
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Aberrant activation of TCL1A promotes stem cell expansion in clonal haematopoiesis.
- 2023
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In: Nature. - 1476-4687. ; 616:7958, s. 755-763
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Journal article (peer-reviewed)abstract
- Mutations in a diverse set of driver genes increase the fitness of haematopoietic stem cells (HSCs), leading to clonal haematopoiesis1. These lesions are precursors for blood cancers2-6, but the basis of their fitness advantage remains largely unknown, partly owing to a paucity of large cohorts in which the clonal expansion rate has been assessed by longitudinal sampling. Here, to circumvent this limitation, we developed a method to infer the expansion rate from data from a single time point. We applied this method to 5,071 people with clonal haematopoiesis. A genome-wide association study revealed that a common inherited polymorphism in the TCL1A promoter was associated with a slower expansion rate in clonal haematopoiesis overall, but the effect varied by driver gene. Those carrying this protective allele exhibited markedly reduced growth rates or prevalence of clones with driver mutations in TET2, ASXL1, SF3B1 and SRSF2, butthis effect was not seen inclones withdriver mutations in DNMT3A. TCL1A was not expressed in normal or DNMT3A-mutated HSCs, but the introduction of mutations in TET2 or ASXL1 led to the expression of TCL1A protein and the expansion of HSCs in vitro. The protective allele restricted TCL1A expression and expansion of mutant HSCs, as did experimentalknockdown of TCL1A expression. Forced expression of TCL1A promoted the expansion of human HSCs in vitro and mouse HSCs in vivo. Our results indicate that the fitness advantage of several commonly mutated driver genes in clonal haematopoiesis may be mediated by TCL1A activation.
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| 2. |
- Al-Handal, Adil Y, 1952, et al.
(author)
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Gomphonemopsis ligowskii, a new diatom (Bacillariophyceae) from the marine Antarctic and a comparison to other Gomphonemopsis
- 2018
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In: Diatom Research. - : Informa UK Limited. - 0269-249X .- 2159-8347. ; 33:1, s. 97-103
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Journal article (peer-reviewed)abstract
- A new marine diatom, Gomphonemopsis ligowskii, is described. Gomphonemopsis ligowskii was found as an epiphyte on the brown macrophyte, Desmarestia anceps, collected from King George Island, Antarctica in January 2016. This species is the first of the genus described from a polar region. It is a small and relatively rare taxon that is characterized by its unique shape and the presence of uniseriate striae, composed of round poroidal areolae on its valve face. The striae are arranged in parallel rows on either side of the axial area, and a row of rounded areolae on both sides of the valve mantle is confined to the wider part of the valve (headpole). A description of valve ultrastructure as well as a comparison with related taxa are provided.
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| 3. |
- Al-Handal, Adil Y, 1952, et al.
(author)
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- Nitzschia biundulata sp. Nov. a new sea ice diatom (bacillariophyceae) from the ross sea, Antarctica
- 2019
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In: Nova Hedwigia: Zeitschrift für Kryptogamenkunde. - : Schweizerbart. - 0029-5035. ; 108:3-4
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Journal article (peer-reviewed)abstract
- - A new marine diatom species, Nitzschia biundulata is described. This species was collected and isolated from the ice cover in the Amundsen Sea, Antarctica during the Austral summer, 2011. The description is based on light and scanning electron microscopes examination as well as molecular analysis including 18S SSU rRNA and rbcL. Morphologically, N. biundulata is characterized by having two extensions of the valve margin in a form of two unequal undulations that are not seen in other taxa of the genus. Molecular sequence data indicated similarity with several Nitzschia species such as Nitzschia apiculata, N. palea, N. capitellata as well as Bacillaria paxillifer. Interestingly, large similarity was found with endosymbiont diatom associated with the dinophyte Peridinium balticum. A comparison with the most related species is provided. © 2019 J. Cramer in Gebrüder Borntraeger Verlagsbuchhandlung, Stuttgart, Germany.
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| 4. |
- Al-Handal, Adil Y, 1952, et al.
(author)
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Two new marine species of Cocconeis (Bacillariophyceae) from the west coast of Sweden
- 2019
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In: European Journal of Taxonomy. - : Museum National D'Histoire Naturelle. - 2118-9773. ; 497, s. 1-16
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Journal article (peer-reviewed)abstract
- This paper is part of a project of studying benthic diatom biodiversity on marine coastal regions of Sweden with focus on rare and less known species. Two new species of Cocconeis Ehrenb. are described from Vrango, a small island in the west coast of Sweden. Both species were found as epiphytic on the green alga Ulva intestinalis L. Cocconeis magnoareolata Al-Handal, Riaux-Gob., R.Jahn & A.K.Wulff sp. nov. is a small species not exceeding 9 mu m in length and characterized by having large subquadrangular areolae on the sternum valve. Cocconeis vrangoensis Al-Handal & Riaux-Gob. sp. nov. appears similar to some taxa of the 'Cocconeis scutellum complex', but differs by its stria density on both valves and variable features of the areola and valvocopula ultrastructure. Detailed descriptions based on light and electron microscopy examination, a comparison with closely related taxa, as well as a description of the habitat of both species are here presented.
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| 5. |
- Bienert, Gern, 2008, et al.
(author)
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A subgroup of plant aquaporins facilitate the bi-directional diffusion of As(OH)3 and Sb(OH)3 across membranes
- 2008
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In: BMC Biology. - : Springer Science and Business Media LLC. - 1741-7007. ; 6:26
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Journal article (peer-reviewed)abstract
- Background Arsenic is a toxic and highly abundant metalloid that endangers human health through drinking water and the food chain. The most common forms of arsenic in the environment are arsenate (As(V)) and arsenite (As(III)). As(V) is a non-functional phosphate analog that enters the food chain via plant phosphate transporters. Inside cells, As(V) becomes reduced to As(III) for subsequent extrusion or compartmentation. Although much is known about As(III) transport and handling in microbes and mammals, the transport systems for As(III) have not yet been characterized in plants. Results Here we show that the Nodulin26-like Intrinsic Proteins (NIPs) AtNIP5;1 and AtNIP6;1 from Arabidopsis thaliana, OsNIP2;1 and OsNIP3;2 from Oryza sativa, and LjNIP5;1 and LjNIP6;1 from Lotus japonicus are bi-directional As(III) channels. Expression of these NIPs sensitized yeast cells to As(III) and antimonite (Sb(III)), and direct transport assays confirmed their ability to facilitate As(III) transport across cell membranes. On medium containing As(V), expression of the same NIPs improved yeast growth, probably due to increased As(III) efflux. Our data furthermore provide evidence that NIPs can discriminate between highly similar substrates and that they may have differential preferences in the direction of transport. A subgroup of As(III) permeable channels that group together in a phylogenetic tree required N-terminal truncation for functional expression in yeast. Conclusion This is the first molecular identification of plant As(III) transport systems and we propose that metalloid transport through NIPs is a conserved and ancient feature. Our observations are potentially of great importance for improved remediation and tolerance of plants, and may provide a key to the development of low arsenic crops for food production.
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