| 1. |
- Zamora, Juan Carlos, et al.
(författare)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Tidskriftsartikel (refereegranskat)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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| 2. |
- Davies, Brandon S J, et al.
(författare)
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GPIHBP1 is responsible for the entry of lipoprotein lipase into capillaries.
- 2010
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Ingår i: Cell metabolism. - : Elsevier BV. - 1932-7420 .- 1550-4131. ; 12:1, s. 42-52
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Tidskriftsartikel (refereegranskat)abstract
- The lipolytic processing of triglyceride-rich lipoproteins by lipoprotein lipase (LPL) is the central event in plasma lipid metabolism, providing lipids for storage in adipose tissue and fuel for vital organs such as the heart. LPL is synthesized and secreted by myocytes and adipocytes, but then finds its way into the lumen of capillaries, where it hydrolyzes lipoprotein triglycerides. The mechanism by which LPL reaches the lumen of capillaries has remained an unresolved problem of plasma lipid metabolism. Here, we show that GPIHBP1 is responsible for the transport of LPL into capillaries. In Gpihbp1-deficient mice, LPL is mislocalized to the interstitial spaces surrounding myocytes and adipocytes. Also, we show that GPIHBP1 is located at the basolateral surface of capillary endothelial cells and actively transports LPL across endothelial cells. Our experiments define the function of GPIHBP1 in triglyceride metabolism and provide a mechanism for the transport of LPL into capillaries.
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| 3. |
- Lee, Roger, et al.
(författare)
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Genetic studies on the functional relevance of the protein prenyltransferases in skin keratinocytes
- 2010
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Ingår i: Oxford Journals About the Journal Human Molecular Genetics. - 0964-6906. ; 19:8, s. 1603-1617
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Tidskriftsartikel (refereegranskat)abstract
- The modification of proteins with farnesyl or geranylgeranyl lipids, a process called protein prenylation, facilitates interactions of proteins with membrane surfaces. Protein prenylation is carried out by a pair of cytosolic enzymes, protein farnesyltransferase (FTase) and protein geranylgeranyltransferase type I (GGTase-I). FTase and GGTase-I have attracted interest as therapeutic targets for both cancer and progeria, but very little information exists on the importance of these enzymes for homeostasis of normal tissues. One study actually suggested that FTase is entirely dispensable. To explore the importance of the protein prenyltransferases for normal tissues, we used conditional knockout alleles for Fntb and Pggt1b (which encode the beta-subunits of FTase and GGTase-I, respectively) and a keratin 14-Cre transgene to create mice lacking FTase or GGTase-I in skin keratinocytes. Keratinocyte-specific Fntb knockout mice were viable but developed severe alopecia. Although hair follicles appeared normal during development, they were morphologically abnormal after birth, and ultrastructural and immunohistochemical studies revealed many apoptotic cells. The interfollicular epidermis of Fntb-deficient mice appeared normal; however, keratinocytes from these mice could not proliferate in culture. As expected, non-farnesylated prelamin A and non-farnesylated DNAJA1 accumulated in Fntb-deficient keratinocytes. Keratinocyte-specific Pggt1b knockout mice survived development but died shortly after birth. Like Fntb-deficient keratinocytes, Pggt1b-deficient keratinocytes did not proliferate in culture. Thus, both FTase and GGTase-I are required for the homeostasis of skin keratinocytes.
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| 4. |
- Olivecrona, Gunilla, et al.
(författare)
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Mutation of conserved cysteines in the Ly6 domain of GPIHBP1 in familial chylomicronemia
- 2010
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Ingår i: Journal of Lipid Research. - New York : Rockefeller U.P.. - 0022-2275 .- 1539-7262. ; 51:6, s. 1535-1545
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Tidskriftsartikel (refereegranskat)abstract
- We investigated a family from northern Sweden in which three of four siblings have congenital chylomicronemia. Lipoprotein lipase (LPL) activity and mass in pre- and post-heparin plasma were low, and LPL release into plasma after heparin injection was delayed. LPL activity and mass in adipose tissue biopsies appeared normal. [35S]Methionine incorporation studies on adipose tissue showed that newly synthesized LPL was normal in size and normally glycosylated. Breast milk from the affected female subjects contained normal to elevated LPL mass and activity levels. The milk had a lower than normal milk lipid content, and the fatty acid composition was compatible with the milk lipids being derived from de novo lipogenesis, rather than from the plasma lipoproteins. Given the delayed release of LPL into the plasma after heparin, we suspected that the chylomicronemia might be caused by mutations in GPIHBP1. Indeed, all three affected siblings were compound heterozygotes for missense mutations involving highly conserved cysteines in the Ly6 domain of GPIHBP1 (C65S and C68G). The mutant GPIHBP1 proteins reached the surface of transfected CHO cells but were defective in their ability to bind LPL (as judged by both cell-based and cell-free LPL binding assays). Thus, the conserved cysteines in the Ly6 domain are crucial for GPIHBP1 function.
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