Biotransformation of cinnamyl alcohol to rosavins by non-transformed wild type and hairy root cultures of Rhodiola kirilowii

Non-transformed wild type (NTWT) and hairy root cultures of Rhodiola kirilowii were grown in medium supplemented with 2.5 mM cinnamyl alcohol as a precursor and/or sucrose (1 %) on the day of inoculation or on the 14th day of culture. Rosarin, rosavin, and rosin were produced by NTWT root culture but only rosarin and rosavin by hairy roots. Approximately 80 and 95 % of the glycosides were released into the medium for NTWT and hairy root cultures, respectively. The highest rosavin yield, 505 ± 106 mg/l, was in hairy root culture when cinnamyl alcohol was applied on the day of inoculation with the addition of sucrose on the 14th day of culture. For rosin production, supplementation with cinnamyl alcohol alone on day 14 was more favourable with the highest amount 74 ± 10 mg/l in NTWT root culture. Only traces of rosarin were detected.     

Potential for Aerobic Methane Oxidation in Carboniferous Coal Measures

Carbon (C), geologically sequestered in coal, is gradually released to the atmosphere as CH₄ and CO₂. Recent anthropogenic activity (coal mining) has rapidly increased the rate of C reallocation from coal deposits into the atmosphere, which has deleterious effect on the climate as both gases are effective infrared absorbers. In the current study we demonstrate that the coal bearing sedimentary rocks possess potential of biological methane oxidation. Viable methanotrophic bacteria, capable of methane oxidation at ambient air and a range of methane concentrations were found in coalbearing formations of the Upper Silesian (USCB) and Lublin Coal Basins (LCB). Factors controlling activity of the aerobic methanotrophic bacteria in the deep subsurface such as, depth, methane concentration, available electron acceptors, moisture and nutrients availability were investigated along with paleoenvironmental factors (temperature changes during and after burial and paleohydrological infiltration). The distribution and activity of the methanotrophic bacteria in the deep subsurface were found to be influenced by geological conditions among which evolution of paleotemperatures and paleohydrological conditions play a predominant role. The data presented along with analysis of molecular composition of the coalbed gases in various coal basins worldwide has led to the conclusion that aerobic methanotrophy may be a widespread process, which, to our knowledge, so far has not been included in investigations concerning C cycling in the subsurface.     

Antioxidant activity and ROS tolerance in triticale (×Triticosecale Wittm.) anthers affect the efficiency of microspore embryogenesis

To verify the hypothesis that cell redox status regulates the process of microspore embryogenesis (ME), reactive oxygen species (ROS) generation and the activity of enzymatic and non-enzymatic antioxidants were analyzed in eight doubled haploid lines of triticale with significant differences in embryogenic potential. The analyses were performed in anthers excised from freshly cut tillers (control) and from low temperature (LT) pre-treated tillers (3 weeks at 4 °C) in which ME has been initiated. Significant associations between ME effectiveness and the variables studied were found. In control cultures, high superoxide dismutase (SOD) activity appeared crucial for microspore viability. On the other hand, positive though non-linear correlation between ME effectiveness and H₂O₂ generation, and negative correlation with catalase (CAT) activity suggest that some threshold level of H₂O₂ is important for successful ME initiation. LT tillers pre-treatment significantly increased H₂O₂ accumulation, which had a negative effect on ME effectiveness. However, even high level of H₂O₂ did not endanger cell viability as long as the cells exhibited high activity of ROS-decomposing enzymes (SOD, CAT and POX). The ability to sustain antioxidative enzyme activity under cold stress in the dark was another important requirement for high effectiveness of ME, allowing for the generation of the signal initiating microspore reprogramming and simultaneously protecting the cells from the toxic effects of ROS production. The role of antioxidative enzymes cannot be replaced even by high activity of non-enzymatic antioxidants. In conclusion, genetically controlled but environmentally modified cell tolerance to oxidative stress seems to play an important role in triticale ME.     

Mannose-Binding Lectin (MBL) and MBL-associated serine protease-2 (MASP-2) in women with malignant and benign ovarian tumours

Mannose-Binding Lectin (MBL) is a serum pattern recognition molecule, able to activate complement in association with MASP proteases. Serum levels of MBL and MASP-2, activities of MBL–MASP complexes, single nucleotide polymorphisms of the MBL2 and MASP2 genes and/or their specific mRNA expression in ovarian sections were investigated in 128 patients suffering from primary ovarian cancer (OC) and compared with 197 controls (C), encompassing both patients with benign ovarian tumours (n = 123) and others with no ovarian pathology (n = 74). MBL deficiency-associated genotypes were more common among OC patients than among controls. The O/O group of genotypes was associated with ovarian cancer (OR 3.5, p = 0.02). In A/A homozygotes, MBL concentrations and activities were elevated in the OC group and correlated with C-reactive protein. Moreover, high MBL serum levels were associated with more advanced disease stage. No differences in distribution of the MASP2 +359 A>G (D120G) SNP or MASP-2 serum levels were found between cancer patients and their controls. However, the highest frequency of the A/G (MASP2) and LXA/O or O/O (MBL2) genotypes was found among OC patients with tumours of G1–2 grade (well/moderately differentiated). Furthermore, MBL deficiency-associated genotypes predicted prolonged survival. None of the parameters investigated correlated with CA125 antigen or patients’ age. The local expression of MBL2 and MASP2 genes was higher in women with ovarian cancer compared with controls. It is concluded that the expression of MBL and MASP-2 is altered in ovarian cancer, possibly indicating involvement of the lectin pathway of complement activation in the disease.     

How well do mean field theories of spiking quadratic-integrate-and-fire networks work in realistic parameter regimes?

We use mean field techniques to compute the distribution of excitatory and inhibitory firing rates in large networks of randomly connected spiking quadratic integrate and fire neurons. These techniques are based on the assumption that activity is asynchronous and Poisson. For most parameter settings these assumptions are strongly violated; nevertheless, so long as the networks are not too synchronous, we find good agreement between mean field prediction and network simulations. Thus, much of the intuition developed for randomly connected networks in the asynchronous regime applies to mildly synchronous networks.     

A discrete pathway for the transfer of intermembrane space proteins across the outer membrane of mitochondria

Mitochondrial proteins are synthesized on cytosolic ribosomes and imported into mitochondria with the help of protein translocases. For the majority of precursor proteins, the role of the translocase of the outer membrane (TOM) and mechanisms of their transport across the outer mitochondrial membrane are well recognized. However, little is known about the mode of membrane translocation for proteins that are targeted to the intermembrane space via the redox-driven mitochondrial intermembrane space import and assembly (MIA) pathway. On the basis of the results obtained from an in organello competition import assay, we hypothesized that MIA-dependent precursor proteins use an alternative pathway to cross the outer mitochondrial membrane. Here we demonstrate that this alternative pathway involves the protein channel formed by Tom40. We sought a translocation intermediate by expressing tagged versions of MIA-dependent proteins in vivo. We identified a transient interaction between our model substrates and Tom40. Of interest, outer membrane translocation did not directly involve other core components of the TOM complex, including Tom22. Thus MIA-dependent proteins take another route across the outer mitochondrial membrane that involves Tom40 in a form that is different from the canonical TOM complex.