Flavonglykoside in Blüten vonPaeonia arborea undPaeonia suffruticosa

Summary Three glycosides have been isolated fromPaeonia arborea: kaempferol-3--glucoside-7--glucoside (Paeonoside), apigenin-7--glucoside, and apigenin-7-rhamnoglucoside (Rhoifolin).Paeonia suffruticosa also contains these three compounds but its main glycoside is kaempferol-3--glucoside (astragalin), which is present inPaeonia arborea only in traces.     

Immune cross-reactivity in celiac disease: anti-gliadin antibodies bind to neuronal synapsin I

Celiac disease is an immune-mediated disorder triggered by ingestion of wheat gliadin and related proteins in genetically susceptible individuals. In addition to the characteristic enteropathy, celiac disease is associated with various extraintestinal manifestations, including neurologic complications such as neuropathy, ataxia, seizures, and neurobehavioral changes. The cause of the neurologic manifestations is unknown, but autoimmunity resulting from molecular mimicry between gliadin and nervous system proteins has been proposed to play a role. In this study, we sought to investigate the immune reactivity of the anti-gliadin Ab response toward neural proteins. We characterized the binding of affinity-purified anti-gliadin Abs from immunized animals to brain proteins by one- and two-dimensional gel electrophoresis, immunoblotting, and peptide mass mapping. The major immunoreactive protein was identified as synapsin I. Anti-gliadin Abs from patients with celiac disease also bound to the protein. Such cross-reactivity may provide clues into the pathogenic mechanism of the neurologic deficits that are associated with gluten sensitivity.     

Secretion of a heat-stable fungalβ-glucanase from transgenic,suspension-cultured barley cells

Transgenic plant cell cultures have a potential for production and secretion of important proteins and peptides. To assess the possibilities of using a stable barley suspension culture for secretion of heterologous proteins in active form, we expressed the cDNA of the thermostable-glucanase (EGI) ofTrichoderma reesei in barley suspension cells. The cDNA coding for EGI and its signal sequence was placed under the control of the CaMV 35S promoter and the construction was transferred to the cells by particle bombardment. Stably transformed lines were obtained by selecting for a cotransformed antibiotic resistance marker. The expression of EGI cDNA led to accumulation of EGI in the culture medium, as shown by analysis with EGI-specific antibodies. Enzymatic assays confirmed that the EGI secreted by the suspension cells retained its activity and thermostable character. Furthermore, it was shown that the enzyme produced by the transgenic suspension culture could be used for degradation of soluble-glucans during mashing.     

Review article number 6 : Plant molluscicides

A review on the application of plant molluscicides in the control of schistosomiasis is presented. Laboratory bioassays are discussed, together with criteria for activity. An attempt has been made to provide a comprehensive list of known molluscicidal natural products.     

Classification of Achromobacter genogroups 2, 5, 7 and 14 as Achromobacter insuavis sp. nov., Achromobacter aegrifaciens sp. nov., Achromobacter anxifer sp. nov. and Achromobacter dolens sp. nov., respectively

The phenotypic and genotypic characteristics of seventeen Achromobacter strains representing MLST genogroups 2, 5, 7 and 14 were examined. Although genogroup 2 and 14 strains shared a DNA–DNA hybridization level of about 70%, the type strains of both genogroups differed in numerous biochemical characteristics and all genogroup 2 and 14 strains could by distinguished by nitrite reduction, denitrification and growth on acetamide. Given the MLST sequence divergence which identified genogroups 2 and 14 as clearly distinct populations, the availability of nrdA sequence analysis as a single locus identification tool for all Achromobacter species and genogroups, and the differential phenotypic characteristics, we propose to formally classify Achromobacter genogroups 2, 5, 7 and 14 as four novel Achromobacter species for which we propose the names Achromobacter insuavis sp. nov. (with strain LMG 26845^T [= CCUG 62426^T] as the type strain), Achromobacter aegrifaciens sp. nov. (with strain LMG 26852^T [= CCUG 62438^T] as the type strain), Achromobacter anxifer sp. nov. (with strain LMG 26857^T [= CCUG 62444^T] as the type strain), and Achromobacter dolens sp. nov. (with strain LMG 26840^T [= CCUG 62421^T] as the type strain).     

Conformational analysis of protein and nucleic acid fragments with the new grid search algorithm FOUND

The new computer algorithm FOUND, which is implemented as an integrated module of the DYANA structure calculation program, is capable of performing systematic local conformation analyses by exhaustive grid searches for arbitrary contiguous fragments of proteins and nucleic acids. It uses torsion angles as the only degrees of freedom to identify all conformations that fulfill the steric and NMR-derived conformational restraints within a contiguous molecular fragment, as defined either by limits on the maximal restraint violations or by the fragment-based DYANA target function value. Sets of mutually dependent torsion angles, for example in ribose rings, are treated as a single degree of freedom. The results of the local conformation analysis include allowed torsion angle ranges and stereospecific assignments for diastereotopic substituents, which are then included in the input of a subsequent structure calculation. FOUND can be used for grid searches comprising up to 13 torsion angles, such as the backbone of a complete -helical turn or dinucleotide fragments in nucleic acids, and yields a significantly higher number of stereospecific assignments than the precursor grid search algorithm HABAS.     

Secretion systems and membrane-associated structures in rust fungi after high pressure freezing and freeze-fracturing

Excellent preservation and new structural details can be demonstrated in rust-infected leaf tissue after high pressure freezing and freeze-fracturing. A tubular-vesicular complex was the most remarkable cytoplasmic structure observed in cells of the bean rust fungus Uromyces appendiculatus var. appendiculatus during its establishement in its host Phaseolus vulgaris. In fungal cells undergoing intensive synthesis of wall material, this membranous system extended throughout the cytoplasm; in addition, vesicles were accumulated adjacent to the plasma membrane. Here, membrane-associated configurations were observed which seem to be involved in exo- and/or endocytotic processes. It is assumed that the tubular-vesicular complex belongs to the endomembraneous system of the bean rust fungus and that it is involved in the synthesis and secretion of wall material.     

Weakly Circadian Cells Improve Resynchrony

The mammalian suprachiasmatic nuclei (SCN) contain thousands of neurons capable of generating near 24-h rhythms. When isolated from their network, SCN neurons exhibit a range of oscillatory phenotypes: sustained or damping oscillations, or arrhythmic patterns. The implications of this variability are unknown. Experimentally, we found that cells within SCN explants recover from pharmacologically-induced desynchrony by re-establishing rhythmicity and synchrony in waves, independent of their intrinsic circadian period We therefore hypothesized that a cell''s location within the network may also critically determine its resynchronization. To test this, we employed a deterministic, mechanistic model of circadian oscillators where we could independently control cell-intrinsic and network-connectivity parameters. We found that small changes in key parameters produced the full range of oscillatory phenotypes seen in biological cells, including similar distributions of period, amplitude and ability to cycle. The model also predicted that weaker oscillators could adjust their phase more readily than stronger oscillators. Using these model cells we explored potential biological consequences of their number and placement within the network. We found that the population synchronized to a higher degree when weak oscillators were at highly connected nodes within the network. A mathematically independent phase-amplitude model reproduced these findings. Thus, small differences in cell-intrinsic parameters contribute to large changes in the oscillatory ability of a cell, but the location of weak oscillators within the network also critically shapes the degree of synchronization for the population.     

Validation of a pressure diameter method for determining modulus and strain of collagen engagement for long branches of bovine pulmonary arteries

Recent studies have shown that capacitance measurements of large arteries provide better prognosis and diagnosis than tests of resistance alone in pulmonary hypertension (Mahapatra et al., 2006, "Relationship of Pulmonary Arterial Capacitance and Mortality in Idiopathic Pulmonary Arterial Hypertension," J. Am. Coll. Cardiol., 47(4), pp. 799-803; Reuben, 1971, "Compliance of the Human Pulmonary Arterial System in Disease," Circ. Res., 29, pp. 40-50]. Decreased arterial capacitance causes increased load to the heart and is the direct result of increased stiffness and elastic modulus of the arterial wall. Here, we validate a pressure-diameter (PD) method for comparing the elastic modulus and collagen engagement for post-hilar pulmonary arteries with a large range of arterial diameter. The tissue mechanics of the post-hilar arteries are not well-characterized in pulmonary hypertension. It is believed that future studies with this method will provide useful insight into the role of passive tissue mechanics of these arteries in the pathophysiology of pulmonary hypertension, eventually improving clinical diagnosis, prognosis, and treatment. Post-hilar pulmonary arteries, excised from healthy and hypertensive calves and healthy cows, were inflated over a range of 0 [mm Hg] to 110 [mm Hg] in an isolated tissue bath. Internal pressure was recorded with an electric pressure catheter. Artery diameter and longitudinal stretch were recorded photographically. Stress-strain data curves were extracted using Lame's law of thick-walled tubes. Radial strips were removed from each section and tested in a uniaxial (MTS) tester for validation. Both the elastic modulus and collagen engagement strain were similar to results obtained by more traditional means. The average difference between measured values of the two methods for collagen engagement strain was 3.3% of the average value of the engagement strain. The average difference between the measured values of the two methods for modulus of elasticity was 7.4% of the average value of the modulus. The maximum, theoretical, relative error for the stress determined with the PD method was calculated at 20.3%. The PD method proved to be a suitable replacement for uniaxial strain tests in comparing collagen engagement strains. The method allowed faster testing of tissues of multiple diameters, while removing the effect of end conditions. The PD method will be of further utility in continued study of tissue mechanics in pulmonary hypertension studies.     

Cofactor‐induced reversible folding of Flavodoxin‐4 from Lactobacillus acidophilus

Flavodoxins in combination with the flavin mononucleotide (FMN) cofactor play important roles for electron transport in prokaryotes. Here, novel insights into the FMN‐binding mechanism to flavodoxins‐4 were obtained from the NMR structures of the apo‐protein from Lactobacillus acidophilus (YP_193882.1) and comparison of its complex with FMN. Extensive reversible conformational changes were observed upon FMN binding and release. The NMR structure of the FMN complex is in agreement with the crystal structure (PDB ID: 3EDO ) and exhibits the characteristic flavodoxin fold, with a central five‐stranded parallel β–sheet and five α‐helices forming an α/β‐sandwich architecture. The structure differs from other flavoproteins in that helix α2 is oriented perpendicular to the β‐sheet and covers the FMN‐binding site. This helix reversibly unfolds upon removal of the FMN ligand, which represents a unique structural rearrangement among flavodoxins.