Heavy metal accumulation in wheat and barley: The effects of soil presence and liquid manure amendment

An experiment was undertaken to evaluate the effect of liquid manure amendment on heavy metal accumulation in wheat and barley. For this purpose, both kinds of seedlings were grown simultaneously in a Petri dish, while wheat seedlings were also grown in pots containing unpolluted agricultural soil. All of the seedlings were irrigated with one of the three prepared solutions: artificial rainwater solution, heavy metal solution and liquid manure solution containing NH₄NO₃, H₃PO₄ and KOH along with equal amounts of heavy metals as in the second solution. Twenty days later, 1 g of plant tissue was digested with the mixture of HNO₃ and H₂O₂ for ICP-OES/HG-ICP-OES analysis. The results showed that the uptake of arsenic and mercury was highest for both plants grown in a Petri dish. Furthermore, the wheat grown in a Petri dish also had a high content of nickel, cadmium and copper, while the pot-grown wheat contained high amounts of iron and manganese, probably due to the adsorption of nickel, cadmium, copper and mercury on soil phases. The lower uptake of all heavy metals was observed after the amendment of liquid manure, with the exception of manganese in wheat and mercury in all plants.     

Intramural optical mapping of V(m) and Ca(i)2+ during long-duration ventricular fibrillation in canine hearts

Intramural gradients of intracellular Ca(2+) (Ca(i)(2+)) Ca(i)(2+) handling, Ca(i)(2+) oscillations, and Ca(i)(2+) transient (CaT) alternans may be important in long-duration ventricular fibrillation (LDVF). However, previous studies of Ca(i)(2+) handling have been limited to recordings from the heart surface during short-duration ventricular fibrillation. To examine whether abnormalities of intramural Ca(i)(2+) handling contribute to LDVF, we measured membrane voltage (V(m)) and Ca(i)(2+) during pacing and LDVF in six perfused canine hearts using five eight-fiber optrodes. Measurements were grouped into epicardial, midwall, and endocardial layers. We found that during pacing at 350-ms cycle length, CaT duration was slightly longer (by ?10%) in endocardial layers than in epicardial layers, whereas action potential duration (APD) exhibited no difference. Rapid pacing at 150-ms cycle length caused alternans in both APD (APD-ALT) and CaT amplitude (CaA-ALT) without significant transmural differences. For 93% of optrode recordings, CaA-ALT was transmurally concordant, whereas APD-ALT was either concordant (36%) or discordant (54%), suggesting that APD-ALT was not caused by CaA-ALT. During LDVF, V(m) and Ca(i)(2+) progressively desynchronized when not every action potential was followed by a CaT. Such desynchronization developed faster in the epicardium than in the other layers. In addition, CaT duration strongly increased (by ～240% at 5 min of LDVF), whereas APD shortened (by ～17%). CaT rises always followed V(m) upstrokes during pacing and LDVF. In conclusion, the fact that V(m) upstrokes always preceded CaTs indicates that spontaneous Ca(i)(2+) oscillations in the working myocardium were not likely the reason for LDVF maintenance. Strong V(m)-Ca(i)(2+) desynchronization and the occurrence of long CaTs during LDVF indicate severely impaired Ca(i)(2+) handling and may potentially contribute to LDVF maintenance.     

Estimated copepod production rate and structure of mesozooplankton communities in the coastal Barents Sea during summer–autumn 2007

The southern Barents Sea is considered to be the most productive area in the Arctic Ocean; however, there are no assessments of daily production rates in the coastal waters. During the summer and autumn of 2007, we investigated the variation of mesozooplankton community structure relative to environmental conditions at 12 coastal stations. Copepods dominated the total zooplankton biomass and abundance during both periods. Diversity indices and the total biomass of zooplankton communities differed significantly between the two seasons. Cluster analyses revealed two distinct groups of stations which were associated with Ura Bay and the adjacent open sea, respectively. Daily production rates of the copepod species examined were calculated using three methods based on: (1) a temperature-dependent equation and (2) two multiple regressions that consider temperature, body weight, and chlorophyll a concentration. Significant seasonal differences for daily production rates were found using all three model equations (p?<?0.05): 358?±?188–1,775?±?791 versus 198?±?85–1,584?±?559?μg?dry?mass?m^?3?day^?1. Results of principal components analyses demonstrated that the abundance and biomass of herbivorous species were related to variation in chlorophyll a concentration while the abundance and biomass of other species (omnivorous copepods and Ctenophora) were related mainly with water temperature and salinity. Mesozooplankton biomass was higher during this study relative to previous studies. Computed copepod production rates were higher compared with other Arctic seas confirming a high productive potential of the coastal southern Barents Sea.     

Interaction of ACTH synthetic fragments with rat adrenal cortex membranes.

Synthetic peptide, corresponding to the amino acid sequence 11-24 of human adrenocorticotropic hormone (ACTH), was labeled with tritium (specific activity of 22 Ci/mmol). [(3)H]ACTH (11-24) was found to bind to rat adrenal cortex membranes with high affinity and specificity (K(d) = 1.8 +/- 0.1 nM). Twenty nine fragments of ACTH (11-24) have been synthesized and their ability to inhibit the specific binding of [(3)H]ACTH (11-24) to adrenocortical membranes has been investigated. Unlabeled fragment ACTH 15-18 (KKRR) was found to replace in a concentration-dependent manner [(3)H]ACTH (11-24) in the receptor-ligand complex (K(i) = 2.3 +/- 0.2 nM). ACTH (15-18) was labeled with tritium (specific activity of 20 Ci/mmol). [(3)H]ACTH (15-18) was found to bind to rat adrenal cortex membranes with high affinity (K(d) = 2.1 +/- 0.1 nM). The specific binding of [(3)H]ACTH (15-18) was inhibited by unlabeled ACTH (11-24) (K(i) = 2.2 +/- 0.1 nM). ACTH (15-18) at the concentration range of 1-1000 nM did not affect the adenylate cyclase activity in adrenocortical membranes.     

Flow Cytometry Analysis of Neural Differentiation Markers Expression in Human Glioblastomas May Predict Their Response to Chemotherapy

Glioblastoma multiforme (GBM) represents an extremely chemoresistant tumour type. Here, authors analysed the immunophenotype of GBM tumours by flow cytometry and correlated the immunophenotypic characteristics with sensitivity to chemotherapy. The expression of selected neural and non-neural differentiation markers including A2B5, CD34, CD45, CD56, CD117, CD133, EGFR, GFAP, Her-2/neu, LIFR, nestin, NGFR, Pgp and vimentin was analysed by flow cytometry in eleven GBM (WHO gr.IV) patients. The sensitivity of tumour cells to a panel of chemotherapeutic agents was tested by the MTT assay. All tumours were positive for A2B5, CD56, nestin and vimentin. CD133, EGFR, LIFR, NGFR and Pgp were expressed only by minor tumour cell subpopulations. CD34, CD45, CD117, GFAP and Her-2/neu were constantly negative. Direct correlations were found between the immunophenotypic markers and chemosensitivity: A2B5 vs lomustine (r² = 0.642, P = 0.033), CD56 vs cisplatin (r² = 0.745, P = 0.013), %Pgp⁺ vs vincristine (r² = 0.846, P = 0.008), and %NGFR⁺ vs daunorubicine (r² = 0.672, P = 0.047) and topotecan (r² = 0.792, P = 0.011). In contrast, inverse correlations were observed between: EGFR vs paclitaxel (r² = ?0.676, P = 0.046), CD133 vs dacarbazine (r² = ?0.636, P = 0.048) and LIFR vs daunorubicine (r² = ?0.878, P = 0.004). Finally, significant associations were also found among sensitivities to different chemotherapeutic agents and among different immunophenotypic markers. In conclusion, histopathologically identical GBM tumours displayed a marked immunophenotypic heterogeneity. The expression of A2B5, CD56, NGFR and Pgp appeared to be associated with chemoresistance whereas CD133, EGFR and LIFR expression was characteristic of chemosensitive tumours. We suggest that flow cytometric imunophenotypic analysis of GBM may predict chemoresponsiveness and help to identify patients who could potentially benefit from chemotherapy.     

DDESC: Dragon database for exploration of sodium channels in human

Background

Hepcidin/LEAP-1 is an iron regulatory hormone originally identified as an antimicrobial peptide. As part of a systematic analysis of the evolution of host defense peptides in primates, we have sequenced the orthologous gene from 14 species of non-human primates.

Results

The sequence of the mature peptide is highly conserved amongst all the analyzed species, being identical to the human one in great apes and gibbons, with a single residue conservative variation in Old-World monkeys and with few substitutions in New-World monkeys.

Conclusion

Our analysis indicates that hepcidin's role as a regulatory hormone, which involves interaction with a conserved receptor (ferroportin), may result in conservation over most of its sequence, with the exception of the stretch between residues 15 and 18, which in New-World monkeys (as well as in other mammals) shows a significant variation, possibly indicating that this structural region is involved in other functions.     

Use of a Reverse Micelle System for Study of Oligomeric Structure of NAD<Superscript>+</Superscript>-Reducing Hydrogenase from <Emphasis Type="Italic">Ralstonia eutropha</Emphasis> H16

Inclusion of an oligomeric enzyme, NAD⁺-dependent hydrogenase from the hydrogen-oxidizing bacterium Ralstonia eutropha, into a system of reverse micelles of different sizes resulted in its dissociation into catalytically active heterodimers and subunits, which were characterized in reactions with various substrates. It was found that: 1) the native tetrameric form of this enzyme catalyzes all types of studied reactions; 2) hydrogenase dimer, HoxHY, is a minimal structural unit catalyzing hydrogenase reaction with an artificial electron donor, reduced methyl viologen; 3) all structural fragments containing FMN and NAD⁺/NADH-binding sites exhibit catalytic activity in diaphorase reactions with one- and two-electron acceptors; 4) small subunits, HoxY and HoxU also exhibit activity in diaphorase reactions with artificial acceptors. These results can be considered as indirect evidence that the second FMN molecule may be associated with one of the small subunits (HoxY or HoxU) of the hydrogenase from R. eutropha.__________Translated from Biokhimiya, Vol. 70, No. 6, 2005, pp. 782–789.Original Russian Text Copyright © 2005 by Tikhonova, Kurkin, Klyachko, Popov.     

Spontaneous curvature of phosphatidic acid and lysophosphatidic acid

The formation of phosphatidic acid (PA) from lysophosphatidic acid (LPA), diacylglycerol, or phosphatidylcholine plays a key role in the regulation of intracellular membrane fission events, but the underlying molecular mechanism has not been resolved. A likely possibility is that PA affects local membrane curvature facilitating membrane bending and fission. To examine this possibility, we determined the spontaneous radius of curvature (R(0p)) of PA and LPA, carrying oleoyl fatty acids, using well-established X-ray diffraction methods. We found that, under physiological conditions of pH and salt concentration (pH 7.0, 150 mM NaCl), the R(0p) values of PA and LPA were -46 A and +20 A, respectively. Thus PA has considerable negative spontaneous curvature while LPA has the most positive spontaneous curvature of any membrane lipid measured to date. The further addition of Ca(2+) did not significantly affect lipid spontaneous curvature; however, omitting NaCl from the hydration buffer greatly reduced the spontaneous curvature of PA, turning it into a cylindrically shaped lipid molecule (R(0p) of -1.3 x 10(2) A). Our quantitative data on the spontaneous radius of curvature of PA and LPA at a physiological pH and salt concentration will be instrumental in developing future models of biomembrane fission.