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- Mårdberg, Kristina, 1970, et al.
(författare)
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Basic amino acids as modulators of an O-linked glycosylation signal of the herpes simplex virus type 1 glycoprotein gC: functional roles in viral infectivity.
- 2004
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 0959-6658 .- 1460-2423. ; 14:7, s. 571-81
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Tidskriftsartikel (refereegranskat)abstract
- The herpes simplex virus type 1 (HSV-1) glycoprotein gC-1 is engaged both in viral attachment and viral immune evasion mechanisms in the infected host. Besides several N-linked glycans, gC-1 contains numerous O-linked glycans, mainly localized in two pronase-resistant clusters in the N-terminal domain of gC-1. In the present study we construct and characterize one gC-1 mutant virus, in which two basic amino acids (114K and 117R) in a putative O-glycosylation sequon were changed to alanine. We found that this modification did not modify the N-linked glycosylation but increased the content of O-linked glycans considerably. Analysis of the O-glycosylation capacity of wild-type and mutant gC-1 was performed by in vitro glycosylation assays with synthetic peptides derived from the mutant region predicted to present new O-glycosylation sites. Thus the mutant peptide region served as a better substrate for polypeptide GalNAc-transferase 2 than the wild-type peptide, resulting in increased rate and number of O-glycan attachment sites. The predicted increase in O-linked glycosylation resulted in two modifications of the biological properties of mutant virus-that is, an impaired binding to cells expressing chondroitin sulfate but not heparan sulfate on the cell surface and a significantly reduced plaque size in cultured cells. The results suggested that basic amino acids present within O-glycosylation signals may down-regulate the amount of O-linked glycans attached to a protein and that substitution of such amino acid residues may have functional consequences for a viral glycoprotein involving virus attachment to permissive cells as well as viral cell-to-cell spread.
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| 2. |
- Karlsson, Charlie, 1945-, et al.
(författare)
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Exit and Entry over the Product Life Cycle : Evidence from the Swedish Manufacturing Industry
- 2003
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Ingår i: Small Business Economics. - : Springer-Verlag New York. - 0921-898X .- 1573-0913. ; 21:2, s. 135-144
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Tidskriftsartikel (refereegranskat)abstract
- In this paper the process of exit and entry of firms in the Swedish manufacturing industry is investigated within the framework of the product life cycle. The product life cycle theory explains how the high degree of uncertainty, as regards product designs and production methods, which is connected to the early stages of the product life cycle requires a high level of knowledge-intensity. Since uncertainty decrease over the product life cycle, less knowledge is needed in production during later stages of the product life cycle. This implies that knowledge-intensity differs for firms that exit and enter in different stages of the product life cycle. Four hypotheses regarding these relationships are stated and empirically tested in this paper, using data at the 5-digit SIC-level for the Swedish manufacturing industry during 1990–1996. The empirical results show that entrants in the early stages of the product life cycle are more knowledge-intensive than incumbent firms. It is also found that firms exiting in early stages of the product life cycle are more knowledge-intensive than firms exiting in later stages.
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| 3. |
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| 4. |
- Lilja, Kristina, 1968-
(författare)
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Marknad och hushåll : Sparande och krediter i Falun 1820-1910 utifrån ett livscykelperspektiv
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The primary aim of this thesis has been to analyse the transformation of the Swedish capital market from a household perspective. The investigation shows that the transition from a mostly private credit market to a more institutionalised credit market took place at the end of the nineteenth century. At this time there were several actors in the credit market that were able to fulfil the diverse needs of credit that different households might have. This need was very much correlated to the household’s particular stage in its life-cycle. In accordance with the life-cycle theory and the permanent income hypothesis, households displayed a savings and consumption pattern that was dependent on income and the burden of expenditure. Households also seemed to have particular difficulty meeting expenditures, so-called life-cycle squeezes, when the household was first started, when the household size was at its peak and when the head of family reached old age, which coincided with a declining capacity to work. The investigation also shows that household savings were meant for old age. Contrary to the assumption made in life-cycle theory, households seemed to intend to provide heirs with an inheritance. This finding is more in keeping with the permanent income hypothesis, which states that households were expected to maintain their assets intact over the course of a life-time.
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| 5. |
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| 6. |
- Nyström, Kristina, 1977, et al.
(författare)
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Real time PCR for monitoring regulation of host gene expression in herpes simplex virus type 1-infected human diploid cells
- 2004
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Ingår i: J Virol Methods. ; 118:2, s. 83-94
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Tidskriftsartikel (refereegranskat)abstract
- Herpes simplex virus type 1 (HSV-1) induces prominent shifts in the rates of transcription of host cellular genes of relevance for the outcome of the viral infection. The quantitative analysis of transcription may be obscured by virus-induced alterations in the levels of RNA encoded by cellular housekeeping genes that are used commonly for normalisation of real time reverse transcription PCR (RT-qPCR). In the present study, we analysed beta-actin, GAPDH and 18S rRNA for their usefulness in normalisation of RT-qPCR analysis of the transcription of the HSV-1 gamma gB-1 gene and FUT5, a cellular gene induced by viral infection. The transcription of these genes was monitored in a TaqMan-based real time RT-PCR system over a 24h interval of virus infection of human embryonic lung fibroblasts. The levels of gB-1 and FUT5 RNA were normalised via difference in the threshold cycle (deltaC(t)) values relative to each and one of the housekeeping genes or calculated in relation to the number of infected cells without any further normalisation. The levels of RNA encoded by beta-actin or GAPDH were found to vary by several orders of magnitude during HSV-1 infection, introducing large errors in the estimation of the gB-1 and FUT5 RNA levels. In contrast, the variation of C(t) values for 18S rRNA was less than one cycle during 24h period of HSV-1 infection. The FUT5 and gB-1 RNA figures obtained by DeltaC(t) normalisation relative 18S rRNA were identical to those calculated in relation to the number of infected cells. These data recommend 18S rRNA for normalisation in HSV-1-infected human cells but discourage the use of beta-actin and GAPDH RNA for this purpose. By applying these procedures, it was shown that the transcription of FUT5 was increased by 50-fold 5-24h after HSV-1 infection and 200-fold by the inhibition of viral DNA replication in HSV-infected cells.
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