Use of a breeding approach for improving biocontrol efficacy of Phlebiopsis gigantea strains against Heterobasidion infection of Norway spruce stumps

Sixty-four wild heterokaryotic isolates of Phlebiopsis gigantea were analysed for asexual spore production, growth rate and competitive ability against Heterobasidion in vitro , as well as growth rate in Norway spruce wood. These P. gigantea traits were considered important for controlling infection of Norway spruce stumps by spores of Heterobasidion spp. Ten most promising P. gigantea isolates were crossed with each other and 172 F₁ progeny heterokaryons were analysed for the above-mentioned traits. Thirteen most promising progeny heterokaryons were selected and their biocontrol ability against infection by Heterobasidion was compared with the parental isolates in stem pieces of Norway spruce. The results indicated that the progeny strains had generally better traits and control efficacy than the parental strains. The genetic effects accounted for a part of the variations between progeny and parental strains. This further suggests that there is a potential to improve the biocontrol properties of P. gigantea through breeding.     

Dual role of endothelin-1 via ETA and ETB receptors in regulation of cardiac contractile function in mice

An increase in coronary perfusion pressure leads to increased cardiac contractility, a phenomenon known as the Gregg effect. Exogenous endothelin (ET)-1 exerts a positive inotropic effect; however, the role of endogenous ET-1 in the contractile response to elevated load is unknown. We characterized here the role of ETA and ETB receptors in regulation of contractility in isolated, perfused mouse hearts subjected to increased coronary flow. Elevation of coronary flow from 2 to 5 ml/min resulted in 80 +/- 10% increase in contractile force (P < 0.001). BQ-788 (ETB receptor antagonist) augmented the load-induced contractile response by 35% (P < 0.05), whereas bosentan (ETA/B receptor antagonist) and BQ-123 (ETA receptor antagonist) attenuated it by 34% and 56%, respectively (P < 0.05). CV-11974 (ANG II type 1 receptor antagonist) did not modify the increase in contractility. These results show that endogenous ET-1 is a key mediator of the Gregg effect in mouse hearts. Moreover, ET-1 has a dual role in the regulation of cardiac contractility: ETA receptor-mediated increase in contractile force is suppressed by ETB receptors.     

Registry of Buildings With Transformer Stations as a Basis for Epidemiological Studies on Health Effects of Extremely Low-Frequency Magnetic Fields

Buildings with indoor transformer stations may serve as a basis for improved epidemiological studies on the health effects of extremely low-frequency magnetic fields (ELF MFs). Previous studies have shown that ELF MF exposure can be adequately assessed based on the fact that MF levels are high in apartments directly above transformers. In this paper, we describe the creation of a registry of Finnish residential buildings with built-in transformer stations and discuss its usability in epidemiological studies. Information obtained from electric utilities and building blueprints were used to identify 677 buildings in which an apartment was located above or adjacent to a transformer station. All apartments in these buildings were classified into exposure categories based on their location in relation to the transformer. Residential histories of these buildings were obtained from the Population Register Centre. Out of the 287,668 individuals who have resided in the buildings, 9,126 of them have resided in an apartment located directly above a transformer station. All information was collected without contacting residents, thus avoiding selection bias. The registry can be linked with data from high-quality nationwide registries to confirm or challenge the reported associations of ELF MF exposure and diseases such as cancer, miscarriage, and Alzheimer's disease. Bioelectromagnetics. 2020;41:34–40 © 2019 Bioelectromagnetics Society.     

Improved Synthesis of Trinucleotide Phosphoramidites and Generation of Randomized Oligonucleotide Libraries

A new method to produce a set of 20 high quality trinucleotide phosphoramidites on a 5–10 g scale each was developed. The procedure starts with condensation reactions of P-components with N-acyl nucleosides, bearing the 3 ′-hydroxyl function protected with 2-azidomethylbenzoyl, to give fully protected dinucleoside phosphates 13. Upon cleavage of dimethoxytrityl group from 13, dinucleoside phosphates 16 are initially transformed into trinucleoside diphosphates 19 and then the 2-azidomethylbenzoyl is selectively removed under neutral conditions to generate trinucleoside diphosphates 5 in excellent yield. Subsequent 3 ′-phosphitylation affords target trinucleotide phosphoramidites 7. When mutagenic oligonucleotides are synthesized employing mixtures of building blocks 7 as well as following the new synthetic protocol, representative oligonucleotide libraries are generated in good yields.     

Activin A and Wnt-dependent specification of human definitive endoderm cells

Activin/Nodal and Wnt signaling are known to play important roles in the regional specification of endoderm. Here we have investigated the effect of the length of stimulation with Activin A plus Wnt3a on the development of hepatic and pancreatic progenitors from the definitive endoderm (DE) cells derived from human pluripotent stem cells (hPSC). We show that DE-cells derived from hPSC with 3 days high Activin A and Wnt3a treatment were able to differentiate further into both tested endodermal lineages. When prolonging the DE-induction protocol from 3 to 5 or 7 days, almost pure DE-marker positive cell populations were obtained. However, these cells had an impaired pancreatic differentiation capacity, while they still developed into hepatocyte-like cells. Further propagation of the DE-cells in the presence of Wnt3a and Activin A led to the complete loss of differentiation capacity into hepatic or pancreatic lineages. When Wnt3a was removed after 24 h from the initiation of the differentiation, the cells were able to differentiate into PDX1+/NKX6.1+ pancreatic progenitors even with longer DE induction time while efficiency of hepatic differentiation was lower. Our results suggest that both the length and the timing of Wnt3a treatment during DE induction are crucial for the final differentiation outcome. Although it is possible to derive apparently pure DE cells with prolonged Activin A/Wnt-stimulation, their progenitor capacity is restricted to a limited time window.     

Acetaldehyde-derived modifications on cytosolic human carbonic anhydrases

Acetaldehyde can generate modifications in several proteins, such as carbonic anhydrase (CA) II. In this study, we extended in vitro investigations on acetaldehyde adduct formation by focusing on the other human cytosolic CA enzymes I, III, VII, and XIII. High-resolution mass spectrometric analysis indicated that acetaldehyde most efficiently formed covalent adducts with CA II and XIII. The binding of up to 19 acetaldehydes in CA II is probably attributable to the high number of lysine residues (n = 24) located mainly on the surface of the enzyme molecule. CA XIII formed more adducts (up to 25) than it contains lysine residues (n = 16) in its primary structure. Acetaldehyde treatment induced only minor changes in CA catalytic activity in most cases. The present study provides the first evidence that acetaldehyde can bind to several cytosolic CA isozymes. The functional consequences of such modifications will be further investigated in vivo by using animal models.     

Structure of the Fab-labeled "breathing" state of native poliovirus

At 37°C, the structure of poliovirus is dynamic, and internal polypeptides VP4 and N terminus of VP1 (residues 1 to 53) externalize reversibly. An Fab fragment of a monospecific antibody, which binds to residues 39 to 55 of VP1, was utilized to locate the N termini of VP1 in native (160S) particles in this "breathing" state. Fab and virus were mixed and imaged via cryogenic electron microscopy. The resulting reconstruction showed the capsid expands similarly to the irreversibly altered cell entry intermediate (135S) particle, but the N terminus of VP1 is located near the 2-fold axes, instead of the "propeller tip" as in 135S particles.     

Element interactions and soil properties affecting the soil-to-plant transfer of six elements relevant to radioactive waste in boreal forest

Cobalt (Co), lead (Pb), molybdenum (Mo), nickel (Ni), uranium (U), and zinc (Zn) are among the elements that have radioactive isotopes in radioactive waste. Soil-to-plant transfer is a key process for possible adverse effects if these radionuclides are accidentally released into the environment. The present study aimed at investigating factors affecting such transfer in boreal forest. The plant species studied were blueberry (Vaccinium myrtillus), May lily (Maianthemum bifolium), narrow buckler fern (Dryopteris carthusiana), rowan (Sorbus aucuparia) and Norway spruce (Picea abies). Regression analyses were carried out to investigate the effects of the chemical composition and physical properties of soil on the soil-to-leaf/needle concentration ratios of Co, Mo, Ni, Pb, U and Zn. Soil potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P) and sulphur (S) concentrations were the most important factors affecting the soil-to-plant transfer of the elements studied. Soil clay and organic matter contents were found to significantly affect plant uptake of Mo, Pb and U. Knowledge of the effects of these factors is helpful for interpretation of the predictions of radioecological models describing soil-to-plant transfer and for improving such models.