The use of morphometric characteristics in the identification of two morphologically similar charophytes: <Emphasis Type="Italic">Chara globularis</Emphasis> and <Emphasis Type="Italic">Chara virgata</Emphasis>

The study reports results of morphometric measurements of two morphologically similar charophytes, Chara globularis Thuill. and Chara virgata Kütz.. Although both species differ in ecological spectra, they can co-occur in the same lakes. Morphological differences given in identification keys can be problematic in the field study. Therefore, additional features were tested and suggested as possibly useful, supplementary differences. 10 individuals of both species growing under similar conditions (littoral of a meromictic, mesotrophic lake, mid-Western Poland) were collected in the vegetation season 2005. Statistical tests evidenced that out of 9 features 6 differed the studied species. Axis diameter, the length of internodes and the length of branchlets revealed the most significant differences. Chara virgata is smaller than Chara globularis even in similar or common habitats. The proposed branchlet length: internode length ratio, higher for Chara virgata than for Chara globularis, can be applied as a useful measure for the species differentiation, particularly under conditions where both charophytes co-occur.     

Clinical evaluation of the simultaneous determination of CA 15-3, CA 125 and sHER2 in breast cancer

Objective We investigated serum levels of CA 15-3, sHER2 and CA 125, and their usefulness in the detection of metastatic disease in breast cancer patients.

Methods The levels of CA 15-3, sHER2 and CA 125 tumour markers were determined in 60 patients, 40 with localized and 20 with metastatic breast carcinoma. The control group consisted of 10 healthy women.

Results We found that, at the time of diagnosis, serum levels of all three tumour markers were elevated in patients with distant metastases, but of minute importance in the detection of any breast cancer. When the data for the individual markers were combined the overall sensitivity of metastases detection with all three markers improved. In this regard, 90% of patients with distant metastases had an increase in serum level of at least one of tested tumour markers. Similar results were obtained using receiver operating characteristic curve (ROC). Moreover, using ROC we defined cut-off values for metastasis detection for each of the tested markers.

Conclusion Our findings indicate that measurement of CA 15-3 serum values in conjunction with sHER2 and CA 15-3 can increase sensitivity in metastasis detection.     

Geometries of stacking interactions between phenanthroline ligands in crystal structures of square-planar metal complexes

Stacking interactions of phenanthroline square-planar complexes in crystal structures were studied by analyzing data from the Cambridge Structural Database. In most of the crystal structures, two phenanthroline complexes were oriented “head to tail.” Phenanthroline complexes show a wide range of overlap geometries in stacking interactions, while short metal–metal distances were not observed. Stacking chains with alternating overlaps were the predominant type of packing in the crystal structures.     

Distribution and Variability of n‐Alkanes in Epicuticular Waxes of Sedum Species from the Central Balkan Peninsula: Chemotaxonomic Importance

For the first time, the n‐alkane distribution and variability of the epicuticular waxes within 22 Sedum taxa was reported with focus on the chemotaxonomy of native Sedum representatives from the central Balkan Peninsula, compared to their relations with four other species of the Crassulaceae family. By GC/MS and GC‐FID identification and quantification, it was established that n‐alkanes C₂₇, C₂₉, C₃₁, C₃₃, and C₃₅ were the dominant constituents of the examined epicuticular wax samples. Applying multivariate statistical analyses including agglomerative hierarchical clustering (AHC) and principal component analysis (PCA), the relation according to the n‐alkane composition between the examined samples was established. It was shown that the n‐alkane variability of the central Balkan Sedum species was considerable and that n‐alkanes might not be very reliable taxonomic markers for these species.     

Lenticel hypertrophy in shoot cultures of Ceratonia siliqua L.

Numerous white surface proliferations appeared in cultures of Ceratonia siliqua L. grown three to four weeks on medium containing 0.5 mg l^-1 BA and 0.1 mg l^-1 IBA. It was histologically confirmed that these proliferations were hypertrophied lenticels. Proliferations appeared first at the basal shoot internode and gradually spread acropetally, covering eventually the whole shoot except the uppermost internodes. Increase of BA concentration in the medium increased both the number of hypertrophied lenticels per shoot and the shoot multiplication index.Abbreviations BA 6-benzylamino-purine - IBA indole-3-butyric acid Dubravka Bojovi-Cveti deceased July 8, 1991.     

Production of phenolic compounds,antioxidant and antimicrobial activities in hairy root and shoot cultures of <Emphasis Type="Italic">Hypericum perforatum</Emphasis> L.

Three hairy root clones of Hypericum perforatum (HR 2, HR 15 and HR 27) transformed with Agrobacterium rhizogenes A4M70GUS and their corresponding regenerated shoot culture clones (HRRS) were compared for differences in growth, production of phenolic compounds, antioxidant and antimicrobial activities. Transgenic clones were selected on the basis of morphological evaluation, genetic and molecular analyses. The clone HR 2 had the highest biomass accumulation, while HR 27 showed the highest shoot regeneration potential. The total phenolics and flavan-3-ols were enhanced in all tested transgenic cultures, while total flavonoids and hypericins were augmented in HRRS clones compared to non-transformed shoots. The HRRS clones produced substantial amounts of chlorogenic acid and 3-p-coumaroylquinic acid. Regarding the flavonoids, they produced significant contents of luteolin hexoside (HRRS 2), quercitrin and quercetin (HRRS 15) and isoquercetin (HRRS 27), while HR 2 and 15 accumulated 4-O-methylkaempferol-O-hexoside and quercetin 6-C-glucoside, respectively. The HR 15 was promising for the production of catechin and procyanidin derivatives and together with its HRRS clone exhibited a high potential for hyperforin and adhyperforin production. All identified naphtodianthrones were confirmed in HRRS 2 and 15 clones. Among xanthones, mangiferin was found as the major compound in HRRS, while trihydroxy-1-metoxy-C-prenyl xanthone was dominant in HR clones. Antimicrobial activity of transgenic cultures revealed that HRRS 15 strongly inhibited the growth of Bacillus cereus, Micrococcus flavus, Pseudomonas aeruginosa and Escherichia coli. Altogether, H. perforatum HR and HRRS cultures could be proposed as promising experimental systems for enhanced production of phenolic compounds with antioxidant and antibacterial properties.     

Influence of landscape structure and land use on <Emphasis Type="Italic">Merodon</Emphasis> and <Emphasis Type="Italic">Cheilosia</Emphasis> (Diptera: Syrphidae): contrasting responses of two genera

Recent advances in landscape ecology have revealed the importance of landscape structure on insect species diversity and composition. We investigated how landscape structure and land use influence species compositions of Cheilosia and Merodon (Diptera: Syrphidae); two phytophagus genera of hoverflies. Our study shows that Shannon’s Diversity Index, Connectance Index, Grazing Intensity, Mean Fractal Dimension Index and Percentage of Agricultural Patches explained 38.6% of the variance in species composition at a 2 km scale, with the total ordination being significant (P?=?0.04, Monte Carlo test, 499 permutations). Merodon and Cheilosia species differ in their responses to land-use change and connectivity, with the latter genus being positively correlated with connectivity and negatively correlated with all other variables. We conclude that connectivity is the primary factor affecting Cheilosia, while most Merodon species demonstrated greater resistance to changes in human-modified ecosystems. Our results suggest that different management efforts, focused on land-use intensity (grazing) or connectivity, seem to be appropriate when trying to conserve these taxa.     

Computational studies on imidazole heme conformations

Abstract Density functional theory computations of heme with ionized propionic acid groups, axially coordinated with two imidazoles, were performed for different mutual orientations of the imidazole planes. Environmental influences from water or protein were considered with a continuum dielectric medium by solving the Poisson equation. In vacuum, optimized geometries yielded imidazole–heme conformations where the NH groups of imidazoles are oriented toward the heme propionic groups in agreement with data from crystal structures of heme proteins. Conformational free-energy dependencies of the mutual orientation of axially ligated imidazoles calculated in protein (=10) and water (=80) environments confirmed the vacuum results, albeit the energy difference between the preferred and the 180° opposite orientations of the imidazole ligand decreased from 3.84 kcal/mol in vacuum to 2.35 and 2.40 kcal/mol in protein and water, respectively. Two main factors determine the imidazole orientation: (1) the direct intramolecular electrostatic interactions of propionic groups with the polar NH groups of imidazole and (2) the electrostatic interaction of the total dipole moment of the imidazole–heme complex with the reaction field. In vacuum, only the first type of interaction is present, while in a dielectric medium the latter effect becomes competitive at high dielectric constant, resulting in a decrease of the orientational preference. Interestingly, the orientational preference of the imidazole axially ligated to heme becomes even more pronounced, if the negatively charged propionates are neutralized by counter charges that mimic salt bridges or protonation of the propionates.Electronic Supplementary Material Supplementary material is available for this article at .     

Cytokinin Profiles of AtCKX2-Overexpressing Potato Plants and the Impact of Altered Cytokinin Homeostasis on Tuberization In Vitro

Genes encoding cytokinin oxidase/dehydrogenase (CKX) enzymes have been used lately to study cytokinin homeostasis in a variety of plant species. In this study AtCKX2-overexpressing potato plants were engineered and grown in vitro as a model system to investigate the effects of altered cytokinin levels on tuber formation and tuber size. Protein extracts from shoots and roots of transformed potato plants exhibited higher CKX activity compared to control plants. Total endogenous cytokinin levels were generally not decreased in AtCKX2 overexpressors. However, levels of bioactive cytokinins were markedly lowered, which was accompanied by increased levels of O- and N-glucosides in some transgenic lines. The AtCKX2-overexpressing plants displayed reduced shoot growth but other symptoms of the ??cytokinin deficiency syndrome?? were not recorded. The transgenic plants were able to produce tubers in noninducing conditions. In inducing conditions they developed larger tubers than control. Tubers were also formed on a greater portion of the analyzed AtCKX2 plants, but with a lower number of tubers per plant compared to control. Taken together, our data suggest that cytokinins cannot be regarded simply as positive or negative regulators of tuberization, at least in vitro. Interactions with other plant hormones that play an important role in control of tuberization, such as gibberellins, should be further studied in detail.     

Exploring immunogenicity of tick salivary AV422 protein in persons exposed to ticks: prospects for utilization

Experimental and Applied Acarology - In order to determine whether conserved tick salivary protein AV422 is immunogenic, the goal of our study was to detect specific IgG response within at-risk...