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- Olalde, I., et al.
(författare)
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The Beaker phenomenon and the genomic transformation of northwest Europe
- 2018
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 555:7695, s. 190-196
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Tidskriftsartikel (refereegranskat)abstract
- From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain's gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries.
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- Hedges, S., et al.
(författare)
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Uroepithelial cells are part of a mucosal cytokine network
- 1994
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Ingår i: Infection and Immunity. - 0019-9567. ; 62:6, s. 2315-2321
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Tidskriftsartikel (refereegranskat)abstract
- This study compared the cytokine production of uroepithelial cell lines in response to gram-negative bacteria and inflammatory cytokines. Human kidney (A498) and bladder (J82) epithelial cell lines were stimulated with either Escherichia coli Hu734, interleukin 1α (IL-1α), or tumor necrosis factor alpha (TNF-α). Supernatant samples were removed, and the RNA was extracted from cells at 0, 2, 6, and 24 h. The secreted cytokine levels were determined by bioassay or immunoassay; mRNA was examined by reverse transcription-PCR. The two cell lines secreted IL-6 and IL-8 constitutively. IL-6 and IL-8 mRNA were constitutively produced in both cell lines; IL-1β mRNA was detected in J82 cells. IL-1α induced significantly higher levels of IL-6 secretion than did E. coli Hu734 or TNF-α. IL-1α and TNF-α induced significantly higher levels of IL-8 secretion than did E. coli Hu734. Secreted IL-1β was not detected; IL-1α and TNF-α were not detected above the levels used for stimulation. IL-1α, IL-1β, IL-6, and IL-8 mRNAs were detected in both cell lines after exposure to the stimulants. TNF-α mRNA was occasionally detected in the J82 cell line after TNF-α stimulation. Cytokine (IL-6 and IL-8) and control (glyceraldehyde 3-phosphate dehydrogenase [G3PDH] and β-actin) mRNA concentrations were quantitated with internal PCR standards. Cytokine mRNA levels relative to β-actin mRNA levels were the highest in E. coli- stimulated cells. In comparison, the cytokine mRNA levels relative to G3PDH mRNA levels were the highest in IL-1α-stimulated cells. β-Actin mRNA levels decreased after bacterial stimulation but not after cytokine stimulation, while G3PDH mRNA levels increased in response to all of the stimulants tested. These results suggested that E. coli Hu734 lowered the β-actin mRNA levels in uroepithelial cells, thus distorting the IL-6 and IL-8 mRNA levels relative to this control. In summary, E. coli IL-1α and TNF-α were found to activate the de novo synthesis and secretion of IL-6 and IL-8 in uroepithelial cells. These results emphasize the role of epithelial cells in cytokine-mediated responses during the early stages of infection.
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