Synthesis of α-mannosylated ergot alkaloids employing α-mannosidase

The ergot alkaloids elymoclavine, ergometrine and chanoclavine were α-mannosylated with α-mannosidase as catalyst. The kinetic reaction with p-nitrophenyl α-mannoside as glycosyl donor gave ca 28 % yield of chanoclavine α-mannoside, whereas the equilibrium reaction with mannose as the glycosyl donor gave ca 11 % yield. However, in the case of elymoclavine and ergometrine, higher yields of α-mannosides were obtained with the equilibrium approach (18 and 13 %).     

Molecular cytogenetic analysis of a duplication Xp in a male: further delineation of a possible sex influencing region on the X chromosome

We describe a male infant with severe mental retardation and autism with a duplication of the short arm of the X chromosome. Chromosome painting confirmed the origin of this X duplication. Molecular cytogenetic analysis with fluorescence in situ hybridization (FISH) identified one copy of the zinc finger protein on the X chromosome (ZFX) and two copies of the steroid sulfatase gene (STS), further delineating the breakpoints. Based on cytogenetic and molecular comparisons of cases from the literature of sex-reversal in dup(X),Y patients and our patient, we suggest that a possible secondary sexinfluencing gene involved in the regulation of sex determination or testis morphogenesis is present at the distal Xp21.1 to p21.2 region.     

Neurocircuitry of the basal ganglia studied by monitoring neurotransmitter release

The neurocircuitries of the basal ganglia are studied with in vivo microdialysis, with special consideration to dopamine transmission and its interaction with other neurotransmitter systems. The aim is to develop experimental models to study the pathophysiology and therapy of neurodegenerative disorders of the basal ganglia, as well as to develop models to study the short- and long-term consequences of perinatal asphyctic lesions. A main goal of these studies is to find and to characterize new treatments for these disorders.     

A spectral correlation function for efficient sequential NMR assignments of uniformly 15N-labeled proteins

Summary A new computer-based approach is described for efficient sequence-specific assignment of uniformly ¹⁵N-labeled proteins. For this purpose three-dimensional ¹⁵N-correlated [¹H, ¹H]-NOESY spectra are divided up into two-dimensional ¹H-¹H strips which extend over the entire spectral width along one dimension and have a width of ca. 100 Hz, centered about the amide proton chemical shifts along the other dimension. A spectral correlation function enables sorting of these strips according to proximity of the corresponding residues in the amino acid sequence. Thereby, starting from a given strip in the spectrum, the probability of its corresponding to the C-terminal neighboring residue is calculated for all other strips from the similarity of their peak patterns with a pattern predicted for the sequentially adjoining residue, as manifested in the scalar product of the vectors representing the predicted and measured peak patterns. Tests with five different proteins containing both -helices and -sheets, and ranging in size from 58 to 165 amino acid residues show that the discrimination achieved between the sequentially neighboring residue and all other residues compares well with that obtained with an unguided interactive search of pairs of sequentially neighboring strips, with important savings in the time needed for complete analysis of 3D ¹⁵N-correlated [¹H, ¹H]-NOESY spectra. The integration of this routine into the program package XEASY ensures that remaining ambiguities can be resolved by visual inspection of the strips, combined with reference to the amino acid sequence and information on spin-system types obtained from additional NMR spectra.Abbreviations 1D, 2D, 3D, 4D one-, two-, three-, four-dimensional - NOE nuclear Overhauser enhancement - NOESY nuclear Overhauser enhancement spectroscopy - COSY correlation spectroscopy - TOCSY total correlation spectroscopy     

Fine root growth and demographic responses to nutrient patches in four old-field plant species

Proliferation of roots in a nutrient patch can occur either as a result of an increase in root length (morphological response) or by a change in root birth or death rates (demographic responses). In this study we attempted to distinguish between these two mechanisms of response to nutrient patches and to compare the responses of four old-field plant species (two annuals, two perennials). For all four species combined, there were significant increases in root numbers and root length in fertilized patches. Root proliferation in fertilized patches was largely due to increased birth (=branching) rates of new roots. However, there was also a significant increase in root death rates in the fertilized patches which reduced the magnitude of the increase in net root numbers. Plots for individual species suggested they differed in the magnitude and timing of root proliferation in fertilized patches due to differences in root birth and death rates. However, because of the limited sample size in this study, there was only a marginally significant difference among species in root birth rates, and no difference in death rates. Further studies are currently underway to better quantify species differences in the demographic mechanism, as well as magnitude, of response to nutrient patches and if this would affect the ability to exploit small-scale heterogeneity in soil resources.     

Neuronal responses to purinoceptor agonists in the leech central nervous system

Exracellular nucleotides like ATP and its derivatives are possible chemical messengers in vertebrate nervous systems. In invertebrate nervous systems, however, little is known about their role in neurotransmission. We have studied the reponse of identified neurones of the leech Hirudo medicinalis to the purinoceptor agonist ATP, ADP, AMP, and adenosine using conventional intracellular microelectrodes and whole-cell patch-clamp recording. Bath application of the agoinsts depolarized the different neurons, but not neuropil glial cells. The most effective responses (up to 10 mV) were observed with ATP (100 μM) or ADP (100 μM) in the noxious and touch cells. In most neurons the nonhydrolyzable ATP derivative ATP-γ-S (5 μM) induced larger depolarizations that 100 μM ATP, indicating that most of the potency of ATP is lost presumably due to its degradation by ectonucleotidases. In medial noxios cells, ATP (100 μM) induced an inward current of 1.7 ± 1.1 nA at a holding potential of ?60 mV. The ATP-induced current-voltage relationship showed an inward rectification and a reversal potential close to 0 m V. In a Na⁺-free extracellular solution, the ATP-induced inward current decreased and in a Na⁺- and Ca²⁺-free saline only a small residual current persisted. The possible P₂ purinoceptor antagonist suramin did not antagonize the ATP-induced current, but itself evoked an inward current and a conductance increase. We conclude that ATP activates nonselective cation channels in medial noxious cells of the leech with the order of potency of purinoceptor agonists ATP ≥ ADP > AMP. The results suggest that these cells express purinoceptors of the P₂ type. 1994 John Wiley & Sons, Inc.     

Stereoselective HPLC bioanalysis of atenolol enantiomers in plasma: Application to a comparative human pharmacokinetic study

An enantioselective HPLC bioassay has been developed relying on extraction of (R)- and (S)-atenolol from alkalinized plasma or serum (pH > 12) into dichloromethane containing 5% (v/v) 1-butanol followed by an achiral derivatization of the drug with phosgene leading to (R)- and (S)-oxazolidine-2-one derivatives. Under these conditions there was quantitative conversion of the acetamido group to the corresponding nitrile. These stable derivatives were separated on a (R,R)-diaminocylohexane-dinitrobenzoyl chiral stationary phase [(R,R)-DACH-DNB] using dichloromethane/methanol 98/2 as mobile phase. Determination limits of 0.5 ng for (R)- and 0.6 ng for (S)-atenolol could be achieved using fluorimetric detection. The assay was applied to a human pharmacokinetic study which was performed in a randomized cross-over, double-blind fashion in 12 healthy volunteers, administering single oral doses of 100 mg (R,S)-, 50 mg (R)-, and 50 mg (S)-atenolol AUC_0–24 and C_max values of (R)-atenolol were slightly but significant higher than those of (S)-atenolol. The R/S ratios were 1.09 for AUC(R)/AUC(S) and 1.03 for C_max (R)/C_max(S) (P < 0.01) respectively after administration of the racemic drug. However, there were no differences between AUC, C_max, and t_½ values of each enantiomer, whether they were administered as single enantiometers or in the form of its racemic mixture. © 1993 Wiley-Liss, Inc.     

Assessment of Biological Activities and Genomic Changes on Microorganisms,Wheat, and Wilding Arise from Poly(pyrazole)

The rapidly growing human population has led to duplicate food production and also reduced product loss. Although the negative effects of synthetic chemicals were recorded, they are still used as agrochemical. The production of non-toxic synthetics makes their use particularly safe. The goal of our research is to evaluate antimicrobial activity of previously synthesized Poly(p-phenylene-1-(2,5-dimethylphenyl)-5-phenyl-1H-pyrazole-3,4-dicarboxy amide) (poly(PDPPD)) against selected Gram-negative, Gram-positive bacteria, and fungus. In addition, the possible genotoxic effects of the poly(PDPPD) were searched on Triticum vulgare and Amaranthus retroflexus seedlings using Random Amplified Polymorphic DNA (RAPD) marker. The binding affinity and binding energies of the synthesized chemical to B-DNA were simulated with AutoDock Vina. It was observed that the poly(PDPPD) affected most of the organisms in a dose-dependent manner. Pseudomonas aeruginosa was the most affected species in tested bacteria at 500 ppm with 21.5 mm diameters. Similarly, a prominent activity was observed for tested fungi. The poly(PDPPD) decreased root and stem length of the Triticum vulgare and Amaranthus retroflexus seedlings and also reduced the genomic template stability (GTS) value of Triticum vulgare more than Amaranthus retroflexus. The binding energy of poly(PDPPD) was found in range of −9.1 and −8.3 kcal/mol for nine residues of B-DNA.     

Evaluation of Acetic Acid-Induced Chronic Gastric Ulcer Healing by Propionyl-L-Carnitine Administration

The aim of our study was to investigate the healing effect of propionyl-L-carnitine (PLC) on chronic gastric ulcers and its underlying mechanisms. This study included rats with gastric ulcers induced by applying serosal glacial acetic acid. These rats were then given either saline (vehicle) or PLC at doses of 60 and 120 mg/kg, administered orally 3 days after ulcer induction for 14 consecutive days. Our study found that treatment with PLC resulted in a reduction of the gastric ulcer area, a faster rate of ulcer healing, and stimulated mucosal restoration. Additionally, the treatment with PLC reduced the number of Iba-1+ M1 macrophages while increasing the number of galectin-3+ M2 macrophages, as well as desmin+ microvessels, and α-SMA+ myofibroblasts in the gastric ulcer bed. The mRNA expression of COX-2, eNOS, TGF-β1, VEGFA, and EGF in the ulcerated gastric mucosa was greater in the PLC-treated groups compared with the vehicle-treated rats. In conclusion, these findings suggest that PLC treatment may accelerate gastric ulcer healing by stimulating mucosal reconstruction, macrophage polarization, angiogenesis, and fibroblast proliferation, as well as fibroblast-myofibroblast transition. This process is associated with the upregulation of TGF-β1, VEGFA, and EGF, as well as modulation of the cyclooxygenase/nitric oxide synthase systems.