| 1. |
- Hederstedt, Lars, et al.
(author)
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New properties of Bacillus subtilis succinate dehydrogenase altered at the active site
- 1989
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In: Biochemical Journal. - : Portland Press Ltd.. - 0264-6021 .- 1470-8728. ; 260:2, s. 491-497
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Journal article (peer-reviewed)abstract
- Mammalian and Escherichia coli succinate dehydrogenase (SDH) and E. coli fumarate reductase apparentlycontain an essential cysteine residue at the active site, as shown by substrate-protectable inactivation withthiol-specific reagents. Bacillus subtilis SDH was found to be resistant to this type of reagent and containsan alanine residue at the amino acid position equivalent to the only invariant cysteine in the flavoproteinsubunit of E. coli succinate oxidoreductases. Substitution of this alanine, at position 252 in the flavoprotein subunit of B. subtilis SDH, by cysteine resulted in an enzyme sensitive to thiol-specific reagents and protectable by substrate. Other biochemical properties of the redesigned SDH were similar to those of the wild-type enzyme. It is concluded that the invariant cysteine in the flavoprotein of E. coli succinate oxidoreductases corresponds to the active site thiol. However, this cysteine is most likely not essential for succinate oxidation and seemingly lacks an assignable specific function. An invariant arginine in juxtaposition to Ala-252 in the flavoprotein of B. subtilis SDH, and to the invariant cysteine in the E. coli homologous enzymes, is probably essential for substrate binding.
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| 2. |
- Rosén, Stefan, et al.
(author)
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Molecular characterization of a saline-soluble lectin from a parasitic fungus : Extensive sequence similarities between fungal lectins
- 1996
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In: European Journal of Biochemistry. - : Wiley. - 0014-2956 .- 1432-1033. ; 238:3, s. 822-829
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Journal article (peer-reviewed)abstract
- It has been proposed that the interactions between several parasite and pathogenic fungi and their hosts are mediated by soluble lectins present in the fungus. We have cloned and analyzed a gene encoding such a lectin (AOL) from the nematophagous fungus Arthrobotrys oligospora (deuteromycete). The deduced primary structure of the AOL gene displayed an extensive similarity (identity 46.3%) to that of a gene encoding a lectin (ABL) recently isolated from the mushroom Agaricus bisporus (basidiomycete), but not to any other fungal, microbial, plant, or animal lectins. The similarities between AOL and ABL were further demonstrated by the observation that an antibody specific for AOL cross-reacted with ABL. Together with data showing that AOL has a binding specificity that is similar to that of ABL [Rosen, S., Bergstrom, J., Karlsson, K.-A., and Tunlid, A. (1996) Eur. J. Biochem. 238, 830-837], these results indicate that AOL and ABL are members of a novel family of saline- soluble lectins present in fungi. Southern blots indicated that there is only one AOL gene in the genome encoding a subunit (monomer) of the lectin. The primary structure of AOL did not show the presence of a typical N-terminal signal sequence. Comparison of the deduced primary structure with the molecular mass of AOL as determined by electrospray mass spectrometry (16153 Da), indicated that AOL has an acetylated N-terminal but no other post- translational modifications, and that a minor isoform is formed by deamidation. Circular dichroism (CD) spectroscopy suggested that the secondary structure of AOl contains 34% β-sheets, 21% α-helix, and 45% turns and coils.
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| 3. |
- Areschoug, Thomas, et al.
(author)
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A Proline-Rich Region with a Highly Periodic Sequence in Streptococcal beta Protein Adopts the Polyproline II Structure and Is Exposed on the Bacterial Surface.
- 2002
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In: Journal of Bacteriology. - 0021-9193. ; 184:22, s. 6376-6383
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Journal article (peer-reviewed)abstract
- Proline-rich regions have been identified in many surface proteins of pathogenic streptococci and staphylococci. These regions have been suggested to be located in cell wall-spanning domains and/or to be required for surface expression of the protein. Because little is known about these regions, which are found in extensively studied and biologically important surface proteins, we characterized the proline-rich region in one such protein, the beta protein of group B streptococci. The proline-rich region in beta, designated the XPZ region, has a proline at every third position, and the sequence is highly periodic in other respects. Immunochemical analysis showed that the XPZ region was not associated with the cell wall but was exposed on the bacterial surface. Moreover, characterization of a beta mutant lacking the XPZ region demonstrated that this region was not required for surface expression of the beta protein. Comparison of the XPZ region in different beta proteins showed that it varied in size but always retained the typical sequence periodicity. Circular dichroism spectroscopy indicated that the XPZ region had the structure of a polyproline II helix, an extended and solvent-exposed structure with exactly three residues per turn. Because of the three-residue sequence periodicity in the XPZ region, it is expected to be amphipathic and to have distinct nonpolar and polar surfaces. This study identified a proline-rich structure with unique properties that is exposed on the surface of an important human pathogen.
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| 4. |
- De Lucca, Anthony J., et al.
(author)
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Antifungal Properties of Wheat Histones (H1-H4) and Purified Wheat Histone H1
- 2011
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In: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 59:13, s. 6933-6939
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Journal article (peer-reviewed)abstract
- Wheat (Triticum spp.) histones H1, H2, H3, and H4 were extracted, and H1 was further purified. The effect of these histones on specific fungi that may or may not be pathogenic to wheat was determined. These fungi included Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Fusarium oxysporum, Fusarium verticillioides, Fusarium solani, Fusarium graminearum, Penicillium digitatum, Penicillium italicum, and Greeneria uvicola. Non-germinated and germinating conidia of these fungi were bioassayed separately. The non-germinated and germinating conidia of all Fusarium species were highly susceptible to the mixture (H1-H4) as well as pure H1, with viability losses of 99-100% found to be significant (p <0.001) at <= 10 mu M or less for the histone mixture and pure H1. F. graminearum was the most sensitive to histone activity. The histones were inactive against all of the non-germinated Penicillium spp. conidia. However, they significantly reduced the viability of the germinating conidia of the Penicillium spp. conidia, with 95% loss at 2.5 mu M. Non-germinated and germinating conidia viability of the Aspergillus spp. and G. uvicola were unaffected when exposed to histones up to 10 mu M. Results indicate that Fusarium spp. pathogenic to wheat are susceptible to wheat histones, indicating that these proteins may be a resistance mechanism in wheat against fungal infection.
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| 5. |
- Hedén Ståhl, Christina, 1972, et al.
(author)
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High-normal blood pressure and long-term risk of type 2 diabetes: 35-year prospective population based cohort study of men
- 2012
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In: BMC cardiovascular disorders. - : Springer Science and Business Media LLC. - 1471-2261. ; 12:1
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Journal article (peer-reviewed)abstract
- ABSTRACT: BACKGROUND: The link between type 2 diabetes and hypertension is well established and the conditions often coexist. High normal blood pressure, defined by WHO-ISH as systolic blood pressure (SBP) 130--139 mm Hg or diastolic blood pressure (DBP) 85--89 mm Hg, has been found to be an independent predictor for type 2 diabetes in studies, although with relatively limited follow-up periods of approximately 10 years. The aim of this study was to investigate whether hypertension, including mildly elevated blood pressure within the normal range, predicted subsequent development of type 2 diabetes in men over an extended follow-up of 35 years. METHODS: Data were derived from the Gothenburg Primary Prevention Study where a random sample of 7 494 men aged 47--55 years underwent a baseline screening investigation in the period 1970--1973. A total of 7 333 men were free from previous history of diabetes at baseline. During a 35-year follow-up diabetes was identified through the Swedish hospital discharge and death registries. The cumulative risk of diabetes adjusted for age and competing risk of death was calculated. Using Cox proportional hazard models we calculated the multiple adjusted hazard ratios (HR) (95% confidence interval (CI)) for diabetes at different blood pressure levels. RESULTS: During a 35-year follow-up, 956 men (13%) were identified with diabetes. The 35-year cumulative risk of diabetes after adjusting for age and competing risk of death in men with SBP levels <130 mm Hg, 130--139 mm Hg, 140--159 mm Hg and >=160 mm Hg were 19%, 30%, 31% and 49%, respectively. The HR for diabetes adjusted for age, body mass index (BMI), cholesterol, antihypertensive treatment, smoking, physical activity and occupation were 1.43 (95% CI 1.12-1.84), 1.43 (95% CI 1.14-1.79) and 1.95 (95% CI 1.55-2.46) for men with SBP 130--139 mm Hg, 140--159 mm Hg, and >= 160 mm Hg, respectively (reference; SBP<130 mm Hg). CONCLUSION: In this population, at mid-life, even high-normal SBP levels were shown to be a significant predictor of type 2 diabetes, independently of BMI and other conventional type 2 diabetes risk factors over an extended follow-up.
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| 6. |
- Hedén Ståhl, Christina, 1972, et al.
(author)
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Incidence of Type 2 diabetes among occupational classes in Sweden: a 35-year follow-up cohort study in middle-aged men
- 2014
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In: Diabetic Medicine. - : Wiley. - 0742-3071 .- 1464-5491. ; 31:6, s. 674-680
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Journal article (peer-reviewed)abstract
- AimsTo assess if low occupational class was an independent predictor of Type 2 diabetes in men in Sweden over a 35-year follow-up, after adjustment for both conventional risk factors and psychological stress. MethodsA random population-based sample of 6874 men aged 47-56 years without a history of diabetes was divided into five occupational classes and the men were followed from 1970 to 2008. Diabetes cases were identified through the Swedish inpatient and death registers. Subdistribution hazard ratios (SHRs) and 95% CIs from competing risk regressions, cumulative incidence and conditional probabilities were calculated, after accounting for the risk of death attributed to other causes. ResultsA total of 907 (13%) men with diabetes were identified over 35 years with a median follow-up of 27.9 years. The cumulative incidence of diabetes, when taking into account death as a competing event, was 11% in high officials, 12% in intermediate non-manual employees, 14% in assistant non-manual employees, 14% in skilled workers, and 16% in unskilled and semi-skilled workers. Men with unskilled and semi-skilled manual occupations had a significantly higher risk of diabetes than high officials (reference) after adjustment for age, BMI, hypertension, smoking and physical activity (SHR 1.39, 95% CI 1.08-1.78). Additional adjustment for self-reported psychological stress did not attenuate the results. ConclusionsA low occupational class suggests a greater risk of Type 2 diabetes, independently of conventional risk factors and psychological stress. Studies with a follow-up of 15 years have shown that Type 2 diabetes disproportionately affects people with a lower socio-economic status. With the world's aging population, it is important to determine if risk factors persist into older age groups. In contrast to many other studies, we adjusted the analysis, not only for conventional risk factors, but also for psychological stress and competing risk of death. The present study shows that low occupational class at mid-life remains an independent predictor for Type 2 diabetes after a 35-year follow-up.
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| 7. |
- Janson, Håkan, et al.
(author)
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Protein D, an immunoglobulin D-binding protein of Haemophilus influenzae: cloning, nucleotide sequence, and expression in Escherichia coli
- 1991
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In: Infection and Immunity. - 1098-5522. ; 59:1, s. 119-125
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Journal article (peer-reviewed)abstract
- The gene for protein D, a membrane-associated protein with specific affinity for human immunoglobulin D, was cloned from a nontypeable strain of Haemophilus influenzae. The gene was expressed in Escherichia coli from an endogenous promoter, and the gene product has an apparent molecular weight equal to that of H. influenzae protein D (42,000). The complete nucleotide sequence of the gene for protein D was determined, and the deduced amino acid sequence of 364 residues includes a putative signal sequence of 18 amino acids containing a consensus sequence, Leu-Ala-Gly-Cys, for bacterial lipoproteins. The sequence of protein D shows no similarity to those of other immunoglobulin-binding proteins. Protein D is the first example of immunoglobulin receptors from gram-negative bacteria that has been cloned and sequenced.
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