| 6391. |
- Tavares, F, et al.
(författare)
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A simple, rapid and non-destructive procedure to extract cell wall-associated proteins from Frankia
- 2000
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Ingår i: Journal of Microbiological Methods. - 0167-7012 .- 1872-8359. ; 39:2, s. 171-178
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Tidskriftsartikel (refereegranskat)abstract
- A simple cell fractionation procedure was developed to extract cell wall-associated proteins from the nitrogen-fixing actinomycete Frankia. The method was based on washing Frankia mycelia in 62.5 mM Tris-HCl (pH 6.8) buffer supplemented with 0.1% Triton X-100 as solubilizing agent. Cell wall-associated proteins were efficiently extracted in less than 10 min, recovering approximately 94.5+/-7.44 pg protein per extraction procedure from exponentially growing cells, corresponding to 50 ml of culture. The amount of cell lysis occurring during the cell wall extraction was estimated to be 1.50+/-0.51%. Three peptidoglycan hydrolases with apparent molecular masses of 4.7, 12.1, and 17.8 kDa were detected by zymography in the cell wall-associated protein fraction. On the contrary, no cell wall lytic enzyme was detected in the cytoplasmic protein fraction. These results indicate that the present method enables a specific extraction of cell wall-associated proteins. Moreover, fluorescein isothiocyanate (FITC) labelling of the cell surface proteins showed an efficient removal of cell wall-associated proteins. Growth of the treated Frankia cells (i.e. cells from which the cell wall-associated proteins were removed) in semi-solid media suggested that these cells were still viable. This technique is of importance for functionality studies of cell wall-associated proteins, particularly for bacteria where traditional cell fractionation methods are difficult to be applied. (C) 2000 Elsevier Science B.V. All rights reserved.
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| 6392. |
- Tavares, F, et al.
(författare)
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DNase-resistant DNA in the extracellular and cell wall-associated fractions of Frankia strains R43 and CcI3
- 2001
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Ingår i: Current Microbiology. - 0343-8651 .- 1432-0991. ; 42:3, s. 168-172
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Tidskriftsartikel (refereegranskat)abstract
- DNases were shown to be present in the extracellular fraction of Frankia strains R43 and CcI3. In spite of this, DNA was found in both the extracellular and cell wall fractions of these strains, and it was shown that extracellular DNA was resistant to the DNases secreted into the culture medium of both Frankia strains. Furthermore, Southern blot analysis under high stringency conditions revealed the chromosomal origin of the cell wall-adsorbed DNA (CW-DNA). Mobility gel band shift assays suggested that the extracellular DNA and the CW-DNA are engaged in complexes with other molecules, most likely proteins, which are probably responsible for the enzymatic resistance observed against extracellular DNase activities. In addition, it was shown that lysis of a small proportion of the cells in the exponential growth phase may account for the DNA being released into the supernatant and adsorbed to the cell wall.
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| 6393. |
- Tavares, Fernando, et al.
(författare)
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Identification and expression studies of a catalase and a bifunctional catalase-peroxidase in Frankia strain R43
- 2003
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Ingår i: Plant and Soil. - : Kluwer Academic Publishers. - 0032-079X .- 1573-5036. ; 254:1, s. 75-81
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Tidskriftsartikel (refereegranskat)abstract
- A monofunctional catalase and a bifunctional catalase-peroxidase were revealed by activity staining of non-denaturing PAGE in Frankia strain R43. Both enzymes were shown to be cytoplasmatic, growth regulated and expressed mainly during the stationary growth phase. Nevertheless, low levels of constitutive expression could also be detected during the early stages of growth. Immunoblot analyses using a polyclonal antibody raised against a catalase-peroxidase purified from Streptomyces reticuli showed a band of 83.2 kDa, with the same growth dependent pattern as obtained by the non-denaturing PAGE analyses. Induction studies revealed that both enzymes were strongly induced by raising the intracellular concentration of H2O2 with paraquat, but not with exogenous H2O2. In addition, no acquisition of tolerance to exogenous H2O2 was observed whatever the pretreatment of the inocula, i.e. despite the expression level of both hydroperoxidases.
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| 6394. |
- Tay, GK, et al.
(författare)
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PERB11 (MIC) : a polymorphic MHC gene is expressed in skin and single nucleotide polymorphisms are associated with psoriasis.
- 2000
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Ingår i: Clinical and Experimental Immunology. - : John Wiley & Sons. - 0009-9104 .- 1365-2249. ; 119:3, s. 553-558
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Tidskriftsartikel (refereegranskat)abstract
- The susceptibility genes for psoriasis remain to be identified. At least one of these must be in the major histocompatibility complex (MHC) to explain associations with alleles at human leucocyte antigen (HLA)-A, -B, -C, -DR, -DQ and C4. In fact, most of these alleles are components of just two ancestral haplotypes (AHs) designated 13.1 and 57.1. Although relevant MHC gene(s) could be within a region of at least 4 Mb, most studies have favoured the area near HLA-B and -C. This region contains a large number of non-HLA genes, many of which are duplicated and polymorphic. Members of one such gene family, PERB11.1 and PERB11.2, are expressed in the skin and are encoded in the region between tumour necrosis factor and HLA-B. To investigate the relationship of PERB11.1 alleles to psoriasis, sequence based typing was performed on 97 patients classified according to age of onset and family history. The frequency of the PERB11.1*06 allele is 44% in type I psoriasis but only 7% in controls (Pc = 0.003 by Fisher's exact test, two-tailed). The major determinant of this association is a single nucleotide polymorphism (SNP) within intron 4. In normal and affected skin, expression of PERB11 is mainly in the basal layer of the epidermis including ducts and follicles. PERB11 is also present in the upper keratin layers but there is relative deficiency in the intermediate layers. These findings suggest a possible role for PERB11 and other MHC genes in the pathogenesis of psoriasis.
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| 6395. |
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| 6396. |
- Tedebrand, Lars-Göran
(författare)
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Introduction
- 2000
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Ingår i: Sex, State and Society. - Umeå : Nyheternas tryckeri KB i Umeå. - 917191871X ; , s. 9-11
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 6397. |
- Tedebrand, Lars-Göran, et al.
(författare)
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Introduction
- 2001
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Ingår i: Nordic Demography in History and Present-Day Society. - Umeå : Umeå universitet. - 9173052035 ; , s. 11-17
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 6398. |
- Tegenborg Falkdalen, Karin, 1965-
(författare)
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Kungen är en kvinna : retorik och praktik kring kvinnliga monarker under tidigmodern tid
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the present dissertation is to investigate and discuss the political debate on female monarchs during the early modern era (principally circa 1600 to 1720), while specifically pro- blematizing the relationship between rhetoric and practice.The study consists of three sections. The first comprises a study of regulations concerning female succession in the era, highlighting the relationship between the principles of gender and consanguinuity. The second section studies the debate both for and against female monarchs in general, analyzing the arguments presented by Swedish and English debatteurs and European legislators. The third section discusses the perception of female monarchs in practice. Here the focus is on Queens Christina (1632-54) and Ulrika Eleonora (1719-1720), who are both compared with each another and other reigning monarchs, primarily the English Queens Elizabeth I (1558-1603), Mary II (1689-94) and Anna Stuart (1702-14). This section is divided into four thematic subsections: female monarchs in relation to ascension to the throne; education; war; and marriage. Furthermore, the opinions of Christina and Ulrika Eleonora themselves on female monarchs and female succession are discussed.This study has attempted to show that the question of the gender of the monarch has had significance for both the rhetoric and practice of female monarchy. It has been shown that the arguments used against female rulers have mainly concentrated on the principle of gender by labelling "female/feminine" as the negative polar opposite of "male/masculine". In contrast, the arguments used in favour of female monarchs have attempted to tone down the signficance of the fact that the monarch was a woman. Instead, the matter of the monarch's gender was discussed in relation to other, more overriding principles for the monarchy as an institution, including birth, dynastic continuity, royal distinctiveness, education, the preservation of order and legitimate succession to the throne. At the same time, this study has shown that traditionally female characteristics could also have a positive effect. One particular problem, both in rhetoric and practice, seems however to have been how and indeed if a female monarch could coordinate her role as sovreign with that of traditionally subordinate wife.
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| 6399. |
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| 6400. |
- Tegnell, Anders, et al.
(författare)
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[Smallpox : eradicated disease and a potential terrorist weapon]
- 2002
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Ingår i: Läkartidningen. - 0023-7205 .- 1652-7518. ; 99:19, s. 2145-2149
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Smallpox is a disease that followed humanity for thousands of years up until thirty years ago. It was possible to eradicate, since an effective live vaccine from crossreacting vaccinia could be developed. Twenty years passed since vaccinations stopped and very few people are protected against the disease today. Variola today has become an object of discussion due to the possibility that it can be used as a bioweapon. Due to the number of complications that can be expected a general vaccination is probably not possible. Research is ongoing to develop new vaccines. Many countries are improving their capabilities to respond to a renewed threat of a smallpox epidemic.
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