Biological activity of Pd(II) complexes with mono- and disubstituted pyridines—Experimental and theoretical studies

Due to the similarity between Pd and Pt, the complexes of palladium(II) can be considered as potential anticancer agents. Activity of six PdCl₂(X₂Py)₂ complexes (Py = pyridine, and X = CH₃ or Cl) was measured by MTT test using MCF7, CCRF-SB, PC3 and human B-lymphoblastoid cell lines. We found that the effect of PdCl₂(X_nPy)₂ was cell-specific and time-dependent. Obtained results were discussed and compared with the activation parameters calculated for the hydrolysis of PdCl₂(X_nPy)₂, indicating a correlation between viability of MCF7 and CCRF-SB cells and rates of hydrolysis of the Pd(II) complexes.     

Fungal metabolites of xanthohumol with potent antiproliferative activity on human cancer cell lines in vitro

Xanthohumol (1) and xanthohumol D (2) were isolated from spent hops. Isoxanthohumol (3) was obtained from xanthohumol by isomerisation in alkaline solution. Six metabolites were obtained as a result of transformation of xanthohumol (1) by selected fungal cultures. Their structures were established on the basis of their spectral data. One of them: 2″-(2′′′-hydroxyisopropyl)-dihydrofurano-[4″,5″:3′,4′]-4′,2-dihydroxy-6′-methoxy-α,β-dihydrochalcone (6) has not been previously reported in the literature. The antioxidant properties of hops flavonoids and xanthohumol derivatives were investigated using the 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method. The effects of these compounds on proliferation of MCF-7, PC-3 and HT-29 human cancer cell lines were determined by the SRB assay. With the exception of one metabolite, all tested compounds showed antiproliferative activity against the tested human cancer lines. α,β-Dihydroxanthohumol (4), obtained through the biotransformation of xanthohumol, showed higher antiproliferative activity against MCF-7 human breast carcinoma cell line than cisplatin, a widely used anticancer therapeutic agent, and a comparably high activity against PC-3 human prostate cancer cell line.     

Activity of the human immortalized endothelial progenitor cell line HEPC-CB.1 supporting in vitro angiogenesis

Molecular Biology Reports - The human HEPC-CB.1 cell line with many characteristics of endothelial progenitor cells (EPC) was tested for its proangiogenic properties as a potentially therapeutic...     

Effect of chemical structure of benzofuran derivatives and reaction conditions on enantioselective properties of Aureobasidium pullulans microorganism contained in Boni Protect antifungal agent

Bioorganic asymmetric reduction of carbonyl compounds is one of the most important fundamental and practical reactions for producing chiral alcohols. The stereoselective bioreduction of prochiral ketones of benzofuran derivatives in the presence of yeast-like fungus Aureobasidium pullulans contained in the antifungal Boni Protect agent was studied. Biotransformations were carried out under moderate conditions in an aqueous and two-phase system and without multiplication of the bioreagent. Despite similar chemical structure, each of the used ketone has been reduced with varying efficiency and selectivity. One of the reasons for these results is the presence of a whole set of oxidoreductases in A. pullulans cells that are sensitive to the smallest changes in the structure of prochiral substrate. The unsymmetrical methyl ketones were biotransformed with the highest selectivity. Aureobasidium pullulans microorganism is less effective in the reduction of unsymmetrical halomethyl ketones. The presence of a heteroatom in the alkyl group significantly decreases the selectivity of the process. Finally, as a result of the preferred hydride ion transfer from the dihydropyridine ring of the cofactor to the carbonyl double bond on the re side, secondary alcohols of the S and R configuration were obtained with moderate to high enantioselectivity (55-99%).     

Artemisia vulgaris,a new host of 16SrV-C phytoplasma related strains infecting black alder in Poland

Yellowing of leaf tissue and strongly deformed shoots were observed in common mugwort (Artemisia vulgaris L.) growing in a nature reserve in Southern Poland. Similar foliage chlorosis together with abnormal shoot proliferation was noticed on alder tree (Alnus glutinosa Gaertn.) growing next to the common mugwort. DNA specific fragments coding 16S rRNA and ribosomal proteins (rp) were amplified from mugwort and alder samples using direct and nested PCR (Polymerase Chain Reaction) assays. Phylogenetic relationships inferred from 16S and rps3 genes indicated that strains infecting mugwort and alder were most closely related to phytoplasmas of subgroups 16SrV-C and 16SrV-D. Based on the restriction fragment length polymorphism (RFLP) analysis of the 16S rDNA, the investigated phytoplasma strains were classified to subgroup 16SrV-C. Two sequence variants of the rps3 gene which differed by a single nucleotide were detected in all analysed samples by pairwise analysis of the aligned reads. Taking into account that this single-nucleotide polymorphism (SNP) occurs among 16SrV-C and 16SrV-D related phytoplasmas and that the phytoplasmas have a single copy of rp operon, we concluded that each plant species was infected by two distinct, closely related phytoplasma strains. To the best of our knowledge, this is the first report of group 16SrV-C related phytoplasmas infecting common mugwort worldwide, adding a new host species that is possibly linked to the spread of the alder pathogen in Eastern Europe. Although alder yellows phytoplasma has been frequently found in Europe, this is the first detection of phytoplasmas associated with alder in Poland.     

Re‐examining how Munc13‐1 facilitates opening of syntaxin‐1

Munc13‐1 is crucial for neurotransmitter release and, together with Munc18‐1, orchestrates assembly of the neuronal SNARE complex formed by syntaxin‐1, SNAP‐25, and synaptobrevin. Assembly starts with syntaxin‐1 folded into a self‐inhibited closed conformation that binds to Munc18‐1. Munc13‐1 is believed to catalyze the opening of syntaxin‐1 to facilitate SNARE complex formation. However, different types of Munc13‐1‐syntaxin‐1 interactions have been reported to underlie this activity, and the critical nature of Munc13‐1 for release may arise because of its key role in bridging the vesicle and plasma membranes. To shed light into the mechanism of action of Munc13‐1, we have used NMR spectroscopy, SNARE complex assembly experiments, and liposome fusion assays. We show that point mutations in a linker region of syntaxin‐1 that forms intrinsic part of the closed conformation strongly impair stimulation of SNARE complex assembly and liposome fusion mediated by Munc13‐1 fragments, even though binding of this linker region to Munc13‐1 is barely detectable. Conversely, the syntaxin‐1 SNARE motif clearly binds to Munc13‐1, but a mutation that disrupts this interaction does not affect SNARE complex assembly or liposome fusion. We also show that Munc13‐1 cannot be replaced by an artificial tethering factor to mediate liposome fusion. Overall, these results emphasize how very weak interactions can play fundamental roles in promoting conformational transitions and strongly support a model whereby the critical nature of Munc13‐1 for neurotransmitter release arises not only from its ability to bridge two membranes but also from an active role in opening syntaxin‐1 via interactions with the linker.     

The Influence of Condition on Permeation of Ca(II) Ions from Solutions of Selected Calcium’s Salts Through Model Membrane

The permeation of calcium’s ions from calcium solutions of fumarate, gluconate, and citrate through model membrane from the donor chamber to the acceptor chamber has been examined. Process was traced depending on the concentration of the appropriate calcium’s salts (1, 2.5, and 5 mmol/l) and pH value of acceptor environment (1.3, 6.2, and 7.4) which imitated natural conditions appearing in the digestive tract. The amount of permeating Ca(II) ions (percent) and their Ca(II) availability AUC (0–6 h) has been determined. In dependence on the conditions, penetration was as follows: 30.3–95.2% of calcium ions from fumarate solution; 73.0–90.1% of Ca(II) from citrate solution; and 19.0–95.0% of Ca from gluconate solution. The investigation indicates that the amount of permeated Ca(II) ions and their availability are connected with the concentration of the calcium salt and pH of acceptor environment. Fumarate and citrate are available at pH value of acceptor environment 1.3 and 6.2 and gluconate at the pH value of 6.2 and 7.4. These substances are practically unavailable from the acceptor environment at pH value 1.3 for gluconate and 7.4 for fumarate. Results suggest that calcium citrate can be available for organism independently from pH value of acceptor environment.     

Glutathione Peroxidase (GSHPx) Activity in the Liver of Red Deer in Relation to Hepatic Selenium Concentrations, Sex, Body Weight and Season of the Year

The purpose of this study was to determine glutathione peroxidase (GSHPx) activity in the liver of red deer in relation to selenium concentrations in the liver, as well as to evaluate changes in GSHPx activity according to sex, body weight and season of the year. Total selenium concentration in the liver of red deer averaged 0.095?±?0.018?μg/g of wet weight. GSHPx activity in the liver of red deer ranged widely from 4.4 to 45.8?U/g of protein. Females were characterized by higher GSHPx activity compared to males (21.2 vs. 17.0?U/g protein). The highest GSHPx activity was recorded in autumn and the lowest in summer. The lowest GSHPx activity in the liver was found in the heaviest animals (>100?kg body weight), averaging 14.0?U/g protein. Animals weighing <66?kg and 66-100?kg were characterized by similar activity of 25.1 and 24.5?U/g, respectively. Despite the differences in GSHPx activity according to sex, body weight and season of the year, these factors had no significant effect on the activity of this enzyme. The main factor regulating GSHPx activity in the liver of examined red deer was selenium concentration.     

<Emphasis Type="Italic">LEAFY COTYLEDON1</Emphasis>, <Emphasis Type="Italic">FUSCA3</Emphasis> expression and auxin treatment in relation to somatic embryogenesis induction in Arabidopsis

The expression pattern of the LEC1 and FUS3 genes during somatic embryogenesis in Arabidopsis explants (immature zygotic embryos) induced in vitro was analysed, using Real-time quantitative PCR (qRT-PCR). The analysis revealed differential expression of LEC1 but not FUS3 within a 30 day time course of somatic embryo development, and a significant auxin-dependent upregulation of LEC1 was found over the time course. In contrast to embryogenic culture, the level of LEC1 and FUS3 expression was noticeably lower in non-embryogenic callus of Col-0 and hormonal mutants (cbp20 and axr4-1) with low SE-efficiency. In addition, the expression profile of LEC1 and FUS3 was followed in the embryogenic culture derived from 35S::LEC2-GR explants. A significant increase of LEC1 but not FUS3 activity was observed under LEC2 overexpression induced in auxin-treated explants. The work provides further experimental evidence on LEC gene involvement in the embryogenic response in Arabidopsis somatic cells, and also implicates LEC1 function in more advanced stages of SE culture in relation to somatic embryo differentiation and development.     

A Model for Calcium Permeation into Small Intestine

An in vitro model was used to simulate the intestinal permeation of calcium ions depending on the type of salt (carbonate, fumarate, citrate, or gluconate), its concentration (1.0, 2.5, 5.0, or 10 mM/l), and pH (1.3, 4.2, 6.2, or 7.5). To simulate the conditions for calcium permeation in a patient in a fasting state, the solutions were placed in contact with segments of small intestine of pig: stomach, duodenum, jejunum, and ileum. The percent permeation, its rate, and half-time were measured in each case. In all cases, the maximum permeation was seen at 1 mM concentration, depending on pH: 100% for carbonate at pH 1.3; 82% for fumarate, pH 6.2; 79.5% for citrate at pH 4.2, and 81% for gluconate at pH 7.4. The maximum rate of permeation (% h⁻¹) was also observed at 1 mM: 2.16 for carbonate at pH 1.3, 0.29 for fumarate at pH 6.2, 0.26 for citrate at pH 4.2, and 0.28 for gluconate at pH 7.4. The shortest half-time permeation (t _1/2, h) for 1 mM solutions depended also on pH (in parentheses): carbonate 0.3 (1.3), fumarate 2.4 (6.2), citrate 2.6 (4.2), and gluconate 2.5 (7.4). The results suggest that calcium carbonate and citrate can be recommended to patients with normal gastric acidity and hyperacidity while fumarate and gluconate to patients with hypoacidity.