Mosses as biomonitors for radioactivity following the Chernobyl accident

In this work 137Cs and 40K radionuclide concentrations in moss collected at NP Djerdap in the period from 1996 to 2009 are presented. Values of the substrate-moss transfer factor for 137Cs and 40K were calculated. The effective and biological half-life of 137Cs in Homalothecium sericeum moss collected in the period from 1996 to 2008 on the archeological locality of Lepenski Vir was also calculated

Vanadate influence on metabolism of sugar phosphates in fungus Phycomyces blakesleeanus.

The biological and chemical basis of vanadium action in fungi is relatively poorly understood. In the present study, we investigate the influence of vanadate (V5+) on phosphate metabolism of Phycomyces blakesleeanus. Addition of V5+ caused increase of sugar phosphates signal intensities in 31P NMR spectra in vivo. HPLC analysis of mycelial phosphate extracts demonstrated increased concentrations of glucose 6 phosphate, fructose 6 phosphate, fructose 1, 6 phosphate and glucose 1 phosphate after V5+ treatment. Influence of V5+ on the levels of fructose 2, 6 phosphate, glucosamine 6 phosphate and glucose 1, 6 phosphate (HPLC), and polyphosphates, UDPG and ATP (31P NMR) was also established. Increase of sugar phosphates content was not observed after addition of vanadyl (V4+), indicating that only vanadate influences its metabolism. Obtained results from in vivo experiments indicate catalytic/inhibitory vanadate action on enzymes involved in reactions of glycolysis and glycogenesis i.e., phosphoglucomutase, phosphofructokinase and glycogen phosphorylase in filamentous fungi

Biochemical and histological characterization of succulent plant Tacitus bellus response to Fusarium verticillioides infection in vitro

We present changes in Tacitus bellus antioxidative system that specifically correspond to subsequent phases of hemibiotroph Fusarium verticillioides infection revealed by histological analysis. T. bellus response to spore germination 6 h post inoculation (hpi), manifested as first oxidative burst, was characterized by transient decrease in malondialdehyde (MDA) content, transient increase in catalase (CAT), low level of superoxide dismutase (SOD) and peroxidase (POD) activity, as well as with transient decrease in total antioxidant capacity (TAC), total phenol content (TPC) and phenylalanine ammonium lyase activity (PAL), and no changes in polyphenol oxidase (PPO) activity, or phenolic profile. During the biotrophic phase of F. verticillioides infection, characterized by hyphae spread intercellularly in epidermal and mesophyll tissue, the host antioxidative system was suppressed. The transition to necrotrophic phase of F. verticillioides infection (inter- and intracellular colonization and sporulation), occurred 3-4 days post inoculation (dpi). During the necrotrophic phase, 5-7 dpi, slowed progression of colonization of T. bellus mesophyll cells occurred and it coincided with sharp increase in MDA content and CAT, SOD and POD activities, but the drop in TAC, TPC content, and PPO activity, as well as the production of phytotoxin fusaric acid. Presented results add to the knowledge of events and mechanisms related to the transition from biotrophy to necrotrophy in F. verticillioides

The interactions of vanadium with Phycomyces blakesleeanus mycelium: enzymatic reduction, transport and metabolic effects

The biological and chemical basis of vanadium action and transport in fungi is relatively poorly understood. In this study we investigated the interactions of vanadium in physiologically-relevant redox states: vanadate (+5) and vanadyl (+4), with mycelium of fungus Phycomyces blakesleeanus using EPR and P-31 NMR spectroscopy and biochemical assays. We determined that P. blakesleeanus reduces V5+ to V4+ in the extracellular compartment by the means of cell surface enzyme with ferricyanide reductase activity, which contains molybdenum molybdopterin as a cofactor. Both, V5+ and V4+ bind to cell wall. They enter the cytoplasm via phosphate transporter and cation channels, respectively, and exhibit different metabolic effects. Vanadate provokes increased biomass production, the effects being inverted to toxic at higher V5+ concentrations. In addition, V5+ activates the synthesis of sugar phosphates and oligophosphates. On the other hand, V4+ exhibits toxic effects even at low concentrations. The V4+ detoxification route involves binding to vacuolar polyphosphates. Altogether our results imply that the mechanism of interaction of vanadium with P. blakesleeanus involves three major steps: extracellular enzymatic V5+/V4+ reduction, V4+ influx, and vacuolar storage, with an additional step -V5+ import occurring at higher vanadate concentrations

Growth inhibition of fungus Phycomyces blakesleeanus by anion channel inhibitors anthracene-9-carboxylic and niflumic acid attained through decrease in cellular respiration and energy metabolites

Increasing resistance of fungal strains to known fungicides has prompted identification of new candidates for fungicides among substances previously used for other purposes. We have tested the effects of known anion channel inhibitors anthracene-9-carboxylic acid (A9C) and niflumic acid (NFA) on growth, energy metabolism and anionic current of mycelium of fungus Phycomyces blakesleeanus. Both inhibitors significantly decreased growth and respiration of mycelium, but complete inhibition was only achieved by 100 and 500 μM NFA for growth and respiration, respectively. A9C had no effect on respiration of human NCI-H460 cell line and very little effect on cucumber root sprout clippings, which nominates this inhibitor for further investigation as a potential new fungicide. Effects of A9C and NFA on respiration of isolated mitochondria of P. blakesleeanus were significantly smaller, which indicates that their inhibitory effect on respiration of mycelium is indirect. NMR spectroscopy showed that both A9C and NFA decrease the levels of ATP and polyphosphates in the mycelium of P. blakesleeanus, but only A9C caused intracellular acidification. Outwardly rectifying, fast inactivating instantaneous anionic current (ORIC) was also reduced to 33±5 and 21±3% of its pre-treatment size by A9C and NFA, respectively, but only in the absence of ATP. It can be assumed from our results that the regulation of ORIC is tightly linked to cellular energy metabolism in P. blakesleeanus, and the decrease in ATP and polyphosphate levels could be a direct cause of growth inhibition.Microbiology (2017), 163(3): 364-37

Influence of vanadium on SP content in perchloric acid extract of <i>P. blakeskeeanus</i> mycelia.

<p><b>A.</b> HPLC chromatograms obtained from control and V⁵⁺ treated mycelia. <b>B.</b> Changes in content of SP caused by V⁵⁺, and V⁴⁺, and control. Statistically significant differences are marked with asterix (n = 7, <i>P</i><0.05).</p

³¹P NMR spectra of <i>P. blakeskeeanus</i> mycelium after addition of: A. 24

<p> µ<b>mol/g_FW of G6P, F6P and G1P into mycelium treated with 80</b> µ<b>mol/g_FW V⁵⁺; B. 80</b> µ<b>mol/g_FW cAMP, 80</b> µ<b>mol/g_FW V⁵⁺, and 80</b> µ<b>mol/g_FW cAMP+80 </b><b>µmol/g_FW V⁵⁺.</b> Positions of added compounds are labeled with arrows.</p

Sugar phopsphates content in perchloric acid extracts of <i>P. blakesleeanus</i> mycelium.

a<p>compound proposed according to retention time and ³¹P NMR chemical shift.</p>b<p>sum of F6P, F1,6P and F2,6P.</p>c<p>relative increase of peak area normalized to the value in control.</p><p>*normalized to MDP signal area.</p