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Fusarium sambucinum astA gene expressed during potato infection is a functional orthologue of Aspergillus nidulans astA
Get PDFSulfate assimilation plays a vital role in prototrophic organisms. Orthologues of the alternative sulfate transporter (AstA) gene from Aspergillus nidulans were identified in the fungal plant pathogens Fusarium sambucinum and F. graminearum. By physiological and biochemical analyses, the AstA orthologues were determined to be able to uptake sulfate from the environment. Similarly to astA in A. nidulans, the FsastA gene was found to be regulated by sulfur metabolite repression (SMR) in a sulfur-dependent manner. In contrast, the FgastA transcript was undetectable, however, when the FgastA gene was expressed heterologously in A. nidulans, the translated FgAstA protein acted as a sulfate transporter. Interestingly, F. sambucinum astA expression was remarkably augmented in infected potato tubers, despite the presence abundant sulfate and was found not to be correlated with plant resistance
Optimized protocol for PFGE analysis of Anginosus (milleri) Streptococci
Get PDFStreptococcus anginosus (milleri) is a diverse group of gram positive bacteria. Molecular methods to establish relationship between strains are poorly developed. Therefore, main tool to study genetic variability is restriction fragment length polymorphism combined with pulsed field gel electrophoresis (RFLP-PFGE). In this communication, we present optimized protocol for S. anginosus PFGE analysis
MLVF analysis of anginosus (milleri) group streptococci.
Get PDFWe developed a new method of typing for anginosus group streptococci (SAG). It is the first SAG-dedicated, PCR-based method, which allows to determine the relationship between strains. The method is based on the detection of tandem repeats among 9 genomic loci and is classified as multilocus variable number tandem repeats fingerprint (MLVF) type of analysis. Using the described method, it is possible to detect over half million MLVF patterns, which correlate with pulsed-field gel electrophoresis profiles. The other advantage of the method is relatively short time from "cell to data", low costs, and easy application for epidemiological and evolutionary studies
Thermodynamics parameters for binding of halogenated benzotriazole inhibitors of human protein kinase CK2α.
Get PDFThe interaction of human CK2α (hCK2α) with nine halogenated benzotriazoles, TBBt and its analogues representing all possible patterns of halogenation on the benzene ring of benzotriazole, was studied by biophysical methods. Thermal stability of protein-ligand complexes, monitored by calorimetric (DSC) and optical (DSF) methods, showed that the increase in the mid-point temperature for unfolding of protein-ligand complexes (i.e. potency of ligand binding to hCK2α) follow the inhibitory activities determined by biochemical assays. The dissociation constant for the ATP-hCK2α complex was estimated with the aid of microscale thermophoresis (MST) as 4.3±1.8μM, and MST-derived dissociation constants determined for halogenated benzotriazoles, when converted according to known ATP concentrations, perfectly reconstruct IC50 values determined by the biochemical assays. Ligand-dependent quenching of tyrosine fluorescence, together with molecular modeling and DSC-derived heats of unfolding, support the hypothesis that halogenated benzotriazoles bind in at least two alternative orientations, and those that are efficient hCK2α inhibitors bind in the orientation which TBBt adopts in its complex with maize CK2α. DSC-derived apparent heat for ligand binding (ΔΔHbind) is driven by intermolecular electrostatic interactions between Lys68 and the triazole ring of the ligand, as indicated by a good correlation between ΔΔHbind and ligand pKa. Overall results, additionally supported by molecular modeling, confirm that a balance of hydrophobic and electrostatic interactions contribute predominantly (~40kJ/mol), relative to possible intermolecular halogen/hydrogen bonding (less than 10kJ/mol), in binding of halogenated benzotriazoles to the ATP-binding site of hCK2α. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases
Structural Model of the Bilitranslocase Transmembrane Domain Supported by NMR and FRET Data.
Get PDFWe present a 3D model of the four transmembrane (TM) helical regions of bilitranslocase (BTL), a structurally uncharacterized protein that transports organic anions across the cell membrane. The model was computed by considering helix-helix interactions as primary constraints, using Monte Carlo simulations. The interactions between the TM2 and TM3 segments have been confirmed by Förster resonance energy transfer (FRET) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy, increasing our confidence in the model. Several insights into the BTL transport mechanism were obtained by analyzing the model. For example, the observed cis-trans Leu-Pro peptide bond isomerization in the TM3 fragment may indicate a key conformational change during anion transport by BTL. Our structural model of BTL may facilitate further studies, including drug discovery
Poa annua L. in the maritime Antarctic: an overview
Get PDFABSTRACT. Poa annua is the only flowering plant species that has established a breeding population in the
maritime Antarctic, through repeated anthropogenic introduction. The first appearance of this species in the Antarctic
was observed in 1953. Annual bluegrass inhabits mainly anthropogenic sites, but recently has entered tundra
communities. The functioning of P. annua in the Antarctic could not have been possible without adaptations that
enable the plants to persist in the specific climatic conditions typical for this zone. Poa annua is highly adaptable
to environmental stress and unstable habitats: huge phenotypic and genotypic variability, small size, plastic life
cycle (life-history types ranging from annual to perennial forms). The spreading of P. annua in the Antarctic
Peninsula region is a classic example of the expansion process following anthropogenic introduction of an invasive
species, and illustrates the dangers to Antarctic terrestrial ecosystems that are associated with increasing human
traffic
Activities of genes controlling sphingolipid metabolism in human fibroblasts treated with flavonoids
Get PDFNatural flavonoids such as genistein, kaempferol and daidzein were previously found to be able to reduce efficiency of glycosaminoglycan synthesis in cells of patients suffering from mucopolysaccharidoses, inherited metabolic diseases with often brain disease symptoms. This feature was employed to test these compounds as potential drugs for treatment other neuronopathic lysosomal storage disorders, in which errors in sphingolipid metabolism occur. In this report, on the basis of DNA microarray analyses and quantitative real time PCR experiments, we present evidence that these compounds modify expression of genes coding for enzymes required for metabolism of sphingolipids in human dermal fibroblasts (HDFa). Expression of several genes involved in sphingolipid synthesis was impaired by tested flavonoids. Therefore, it is tempting to speculate that they may be considered as potential drugs in treatment of LSD, in which accumulation
of sphingolipids, especially glycosphingolipids, occurs. Nevertheless, further studies on more advances models are required to test this hypothesis and to assess a therapeutic
potential for flavonoids in this group of metabolic brain diseases
Bacteriophages: 100 years of the history of studies on model viruses in molecular biology
Get PDFOne hundred years ago, in 1915, Frederick Twort
has published an article in which he described factors
that could destroy bacterial cells [1]. In fact, he did
not know at that time that these factors are viruses,
however, retrospective analyses show undoubtedly that
he found bacteria-infecting agents, known today as
bacteriophages. The history of further studies on these
viruses is fascinating, and underlines the role of model
organisms in development of molecular biology, as
well as the importance of deep understanding of their
functions for applications of biological subjects. In this
short editorial article, we will present an overview on the
history of studies on bacteriophages and their importance
in current molecular biology and medicine
Morphology, ultrastructure and ecology of Muriella decolor (Chlorophyta) from subaerial habitats in Poland and the Antarctic.
Get PDFThis paper offers a comparison of Muriella decolor specimens from different
geographical regions and habitats (limestone caves in Poland and ice denuded areas near the
Ecology Glacier, King George Island, South Shetland Islands, West Antarctic). Morpho−
logical and cytological variability, ecology and life strategies of M. decolor were studied in
fresh samples, and also in cultures grown on agar plates. The complete life cycle, with de−
tailed ultrastructural (LM and TEM) analysis are presented. The electron microscopic ob−
servations prove that materials identified as M. decolor collected in Poland and the Antarc−
tic have distinct ultrastructural features. These include the chloroplast lamella arrangement,
mitochondrial cristae structure and the cell wall thickness
