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Anna Johansson

Publications and source records attributed to Anna Johansson.

11 recordsLinked to original sources
PubMed2006

Early responses in the Arabidopsis-Verticillium longisporum pathosystem are dependent on NDR1, JA- and ET-associated signals via cytosolic NPR1 and RFO1.

The responses of Arabidopsis accessions and characterized genotypes were used to explore components in the early defense responses to the soilborne fungus Verticillium longisporum. V. longisporum susceptibility was found to be a complex trait, in which different disease phenotypes, such as stunting, altered flowering time, weight loss, and chlorosis were perceived differently across genotypes. A Bay-0 x Shahdara recombinant inbred line population was used to identify two loci on chromosomes 2 and 3 of Bay-0 origin that caused enhanced chlorosis after V. longisporum challenge. Furthermore, the observation that a mutation in RFO1 in Col-0 resulted in susceptibility whereas the natural rfo1 allele in Ty-0 showed a high degree of resistance to the pathogen supports the hypothesis that several resistance quantitative trait loci reside among Arabidopsis accessions. Analysis of mutants impaired in known pathogen response pathways revealed an enhanced susceptibility in ein2-1, ein4-1, ein6-1, esa1-1, and pad1-1, but not in other jasmonic acid (JA)-, ethylene (ET)-, or camalexin-deficient mutants, suggesting that V. longisporum resistance is regulated via a hitherto unknown JA- and ET-associated pathway. Pretreatments with the ET precursor 1-aminocyclo-propane-1-carboxylic acid (ACC) or methyl jasmonate (MeJA) caused enhanced resistance to V. longisporum. Mutants in the salicylic acid (SA) pathway (eds1-1, NahG, npr1-3, pad4-1, and sid2-1) did not show enhanced susceptibility to V. longisporum. In contrast, the more severe npr1-1 allele displayed enhanced V. longisporum susceptibility and decreased responses to ACC or MeJA pretreatments. This shows that cytosolic NPR1, in addition to SA responses, is required for JA- and ET-mediated V. longisporum resistance. Expression of the SA-dependent PR-1 and PR-2 and the ET-dependent PR-4 were increased 7 days postinoculation with V. longisporum. This indicates increased levels of SA and ET in response to V. longisporum inoculation. The R-gene signaling mutant ndr1-1 was found to be susceptible to V. longisporum, which could be complemented by ACC or MeJA pretreatments, in contrast to the rfo1 T-DNA mutant, which remained susceptible, suggesting that RFO1 (Fusarium oxysporum resistance) and NDR1 (nonrace specific disease resistance 1) activate two distinct signaling pathways for V. longisporum resistance.

Acetates↗
PubMed2006

Inflammatory response to a titanium surface with potential bioactive properties: an in vitro study.

BACKGROUND: The current hard tissue implants research aims to accelerate bone healing by designing surfaces that are bioactive. However, the role of the inflammatory response to these surfaces is so far incompletely described. PURPOSE: The aim of the study was to evaluate early inflammatory response in vitro to a potentially bioactive surface--an anodized surface with Mg ions incorporated (anodized/Mg)--and to compare it to a turned, a blasted, and an anodized surface. MATERIALS AND METHODS: An interferometer was used for topographical characterizations. The disks were incubated with human mononuclear cells. Adherent cells were investigated with respect to number of cells, viability, differentiation, and cytokine production with and without lipopolysaccharide stimulation after 24 and 72 hours. RESULTS: The number of adhered mononuclear cells differed significantly between the different modified surfaces, with the highest number on the anodized surface. However, there were no significant differences in cytokine production and differentiation between the different modified surfaces. The amount of anti-inflammatory mediator interleukin-10 remained over time, while the number of cells and pro-inflammatory cytokine tumor necrosis factor-alpha decreased. The cells were viable on all surfaces, respectively. CONCLUSION: The anodized surfaces with and without Mg ions showed an increased cell adherence, however, otherwise an inflammatory response similar to the turned and blasted surfaces. Furthermore, the potentially bioactive anodized/Mg surface showed a similar response to the TiUnite-like anodized surface despite the former having a surface roughness of a smoother character.

Cell Adhesion↗
PubMed2005

Absolute asymmetric synthesis of stereochemically labile aldehyde helicates and subsequent chirality transfer reactions.

Helical complexes formed between aluminum tris(2,6-diphenylphenoxide) (ATPH) and five different aldehydes have been prepared and structurally characterized by X-ray diffraction. It was found that [Al(OC6H3Ph2)3PhCHO] (2), [Al(OC6H3Ph2)3(4-CH3C6H4CHO)] (3), [Al(OC6H3Ph2)3(4-tBuC6H4CHO)] (4), and [Al(OC6H3Ph2)3(p-CH3OC6H4CHO)] (5) all crystallize as conglomerates, while crystals of [Al(OC6H3Ph2)3(o-CH3OC6H4CHO)] (6) are racemic. Supramolecular CH/pi interactions between molecules in crystals of 2-5 that enable stereochemical information to be mediated in three dimensions have been identified and explain the high frequency of conglomerate formation among ATPH helicates. Since 2-5 are stereochemically labile and thus enantiomerize rapidly in solution, the conglomerates can be resolved by crystallization-induced asymmetric transformation. The determination of the enantiomeric excess (ee) in solid samples of stereochemically labile molecules is not trivial, but solid-state CD spectroscopic data, anomalous dispersion data, and the ee values in alkylation reactions all indicate that preferential crystallization of 2-5 yields an essentially enantiopure product. Thus the preparation of 2-5 constitute new examples of absolute asymmetric synthesis. The helical chirality can be transferred (and thus trapped) to alcohols (with ee values of up to 16%) in crystal-to-crystal reactions with achiral organometallic reagents.

Journal Article↗
PubMed2005

Total spontaneous resolution of chiral covalent networks from stereochemically labile metal complexes.

Stereochemically labile copper and zinc complexes with the N,N'-dimethylethylenediamine ligand (dmeda) have been shown to be promising precursors for the total spontaneous resolution of chiral covalent networks. (N,N')-[Cu(NO3)2(dmeda)]infinity crystallises as a conglomerate and yields either enantiopure (R,R)-1 or enantiopure (S,S)-1. A mixed-valence copper(I/II) complex, [{Cu(II)Br2(dmeda)}3(Cu(I)Br)2]infinity (2), which crystallises as a pair of interpenetrating chiral (10,3)-a nets, is formed from CuBr, CuBr2 and dmeda. One net contains ligands with solely (R,R) configuration and exhibits helices with (P) configuration while the other has solely (S,S)-dmeda ligands and gives rise to a net in which the helices have (M) configuration. The whole crystalline arrangement is racemic, because the interpenetrating chiral nets are of opposite handedness. With zinc chloride (R,S)-[ZnCl(dmeda)2]2[ZnCl4] (3) is obtained, which is a network structure, although not chiral. Total spontaneous resolution of stereochemically labile metal complexes formed from achiral or racemic building blocks is suggested as a viable route for the preparation of covalent chiral networks. Once the absolute structure of the compound has been determined by X-ray crystallography, a quantitative determination of the enantiomeric excess of the bulk product can be undertaken by means of solid-state CD spectroscopy.

Journal Article↗
PubMed2005

Altered levels of angiopoietin 1 and tie 2 are associated with androgen-regulated vascular regression and growth in the ventral prostate in adult mice and rats.

The involution of the rat ventral prostate gland after castration could be caused by primary changes in the vasculature. To explore the mechanisms, we studied the effects of castration and testosterone treatment on the vasculature in the ventral prostate in adult rats and mice. Androgen receptor expression, vascular morphology, and the expression of angiopoietin (ang) 1 and 2 and their receptor tie 2 were examined 1, 3, and 7 d after castration and after testosterone treatment of castrated animals using stereological methods, immunohistochemistry, laser capture microdissection, and Western blotting. One day after castration, the percentage of blood vessels covered with smooth muscle actin, endothelial cell proliferation, and vascular volume had decreased, whereas endothelial cell apoptosis had increased. Simultaneously, ang 1 and tie 2 protein levels decreased. Nuclear expression of androgen receptor was observed not only in glandular and stroma smooth muscle cells but also in the mural cells of prostate arteries and veins and was markedly down-regulated already 1 d after castration. Testosterone administration of castrated mice and rats reversed all the observed effects. At the mRNA level, tie 2 was exclusively, but ang 1 predominantly, expressed in the stroma, compared with the epithelial compartment. Local delivery of soluble tie 2 during testosterone-stimulated growth, inhibited vascular maturation and increased vascular volume and leukocyte infiltration compared with controls. We conclude that androgens may regulate the prostate vasculature by direct effects on mural vascular cells and by influencing the secretion of the angiopoietins, in above all, the stroma cells.

Androgens↗
PubMed2003

Localized expression of angiopoietin 1 and 2 may explain unique characteristics of the rat testicular microvasculature.

The testicular vasculature is unique in several ways. The unfenestrated endothelial cells constitute one part of the blood-testis barrier, and testicular microvessels are normally resistant to inflammation mediators. At the same time that angiogenic factors and inflammation mediators are constitutively produced, the proportion of proliferating endothelial cells is considerably higher than in other organs, but new blood vessels are not formed. Hormonal stimulation of the testis with hCG increase endothelial cell proliferation, vascular permeability, and sensitivity to locally injected inflammation mediators. In the present study, we examined whether local expression of angiopoietin (ang) 1, an inhibitor of vascular leakage and sprouting angiogenesis, and its antagonist, ang 2, could be involved in establishing this vascular phenotype. Using reverse transcription-polymerase chain reaction and immunohistochemistry, we demonstrate that testicular vascular endothelial growth factor-A (VEGF-A), ang 1, ang 2, and the ang-receptor tie 2 are expressed in the testis and that hormonal stimulation with hCG is accompanied by increased expression of VEGF-A and ang 2. The ang 1 protein is expressed in testicular microvessels under basal conditions, and it is largely unaffected after hCG stimulation. Expression of ang 2 in microvessels, in contrast, is low under basal conditions and is up-regulated by hCG. Intratesticular injection of human recombinant ang 1 protein inhibits hCG-induced increase in vascular permeability. Injection of ang 2 in the testis increases endothelial cell proliferation and the volume of the interstitial space. We therefore suggest that ang 1 stabilizes testicular microvessels under basal conditions and that a shift in this balance caused by increased ang 2, together with increased VEGF-A, allows vascular leakage, high endothelial cell proliferation, and presumably, vascular growth after hormonal stimulation.

Angiopoietin-1↗
PubMed2003

Alterations of mitochondrial function and correlations with personality traits in selected major depressive disorder patients.

BACKGROUND: Increased occurrence of several physical conditions has been reported in patients with depressive disorders. Various physical conditions and depressive disorder have been reported in patients with mitochondrial disorders. The aim of this study was to investigate mitochondrial function in selected depressed patients in search of an aetiological or pathophysiological factor common to both depression and physical symptoms. METHODS: Muscle biopsy was performed in 28 patients with a lifetime prevalence of major depressive disorder (MDD), and at least three chronic physical conditions that have been reported to be common in depressive as well as in mitochondrial disorders. Morphologic and biochemical investigations including mitochondrial ATP production rate (MAPR) by the bioluminometric method, spectrophotometric analyses of mitochondrial enzymes, and long-PCR and Southern blot techniques to detect mitochondrial DNA (mtDNA) deletions were performed. The Karolinska Scales of Personality (KSP) with 15 scales assessing vulnerability to psychopathology was filled in by 21 patients. RESULTS: Decreases of MAPR and enzyme ratios were found in the patients in comparison with controls (P<0.01). Deletions of mtDNA assessed with long-PCR were more frequent in patients than in controls (chi-square test P<0.05). Correlations were found between MAPR and the KSP scales 'Somatic Anxiety', 'Psychasthenia', and 'Suspicion' (P<0.01). LIMITATIONS: Results cannot be compared with previous studies, and cannot be generalized to all MDD patients. Individually matched controls were not available. CONCLUSIONS: The results suggest that mitochondrial dysfunction is associated with vulnerability to psychopathology in this selected patient group.

Adult↗
PubMed2003

Comparative analysis of CYP3A expression in human liver suggests only a minor role for CYP3A5 in drug metabolism.

To study mechanisms behind the interindividual variability in CYP3A expression and the relative contribution of the different CYP3A enzymes to the overall CYP3A activity, we have analyzed CYP3A4, CYP3A5, CYP3A43, and PXR mRNA and CYP3A4 and CYP3A5 protein expression, catalytic activity, and polymorphism in the CYP3A5 gene in a panel of 46 Caucasian human livers. Protein quantification was performed by Western blotting using enzyme-specific antibodies directed to the C termini of CYP3A4 or CYP3A5, and carrier protein-coupled peptides as standards. The mRNA levels were determined by quantitative real-time PCR. CYP3A activity was measured by analysis of the rate of testosterone 6beta-hydroxylation. A correlation existed between all CYP3A and PXR mRNA transcripts measured. The interindividual variability in CYP3A4 and CYP3A5 mRNA expression was higher than that of CYP3A protein and activity. The CYP3A5 protein was expressed at quantifiable levels in 5 (10.9%) of the livers. Four of those were heterozygous for the CYP3A5*1 allele and had CYP3A5 protein at a mean level of 17% of that of total CYP3A, whereas one liver sample was from a CYP3A5*3 homozygote individual having lower amounts of CYP3A5. In total, CYP3A5 only contributed 2% of the overall CYP3A protein among all samples. In conclusion, our data indicate that CYP3A4, CYP3A5, CYP3A43, and PXR hepatic mRNA expression correlate, indicating common regulatory features, and that the contribution of CYP3A5 to hepatic drug metabolism in Caucasians is insignificant.

Alleles↗
PubMed2002

Subchronic toxicity of Baltic herring oil and its fractions in the rat II: Clinical observations and toxicological parameters.

This study aimed to increase the knowledge about the toxicity of fish-derived organohalogen pollutants in mammals. The strategy chosen was to separate organohalogen pollutants derived from Baltic herring (Clupea harengus) fillet, in order to obtain fractions with differing proportions of identified and unidentified halogenated pollutants, and to perform a subchronic toxicity study in rats, essentially according to the OECD guidelines, at three dose levels. Nordic Sea lodda (Mallotus villosus) oil, with low levels of persistent organohalogen pollutants, was used as an additional control diet. The toxicological examination showed that exposure to Baltic herring oil and its fractions at dose levels corresponding to a human intake in the range of 1.6 to 34.4 kg Baltic herring per week resulted in minimal effects. The spectrum of effects was similar to that, which is observed after low-level exposure to pollutants such as chlorinated dibenzo-p-dioxins and dibenzofurans (CDD/F) and chlorinated biphenyls, despite the fact that these contaminants contribute to a minor part of the extractable organically bound chlorine (EOCI). The study confirmed previous findings that induction of hepatic ethoxyresorufin deethylase (EROD) activity takes place at daily intake levels 0.15 ng fish-derived CDD/F-TEQs/kg body weight. The study also demonstrated that hepatic vitamin A reduction takes place at somewhat higher daily exposure levels, i.e. 0.16-0.30 ng fish-derived CDD/F-TEQs/kg body weight. Halogenated fatty acids, the major component of EOCI, could not be linked to any of the measured effects. From a risk management point of view, the study provides important new information of effect levels for Ah-receptor mediated responses following low level exposure to organohalogen compounds from a matrix relevant for human exposure.

Animals↗