Management of nursery practices for efficient ectomycorrhizal fungi application in the production of Quercus ilex

The application of ectomycorrhizal (ECM) fungi on forest nursery production is regarded as part of good management practice. However, before employing large scale inoculations in a nursery the interaction between ECM symbionts, growth substrate and fertilisation input should be studied to select the most suitable nursery practices for promoting plant growth and ECM colonisation. In this study, seedlings of Quercus ilex were inoculated with Paxillus involutus, Hebeloma mesophaeum or Cenococcum geophilum and grown in three different substrates commonly used in forest nurseries: peat-based compost, forest soil or composted pine bark. The effect of various fertilisation regimes was also studied. The choice of substrate had a significant effect on plant growth and ECM colonisation. The most appropriate combination of substrate and ECM fungus for Q. ilex growth and nutrition was peat and H. mesophaeum. Plants grown on a peat-based compost and inoculated with H. mesophaeum had a significantly greater biomass and leaf phosphorus concentration without fertilisation. Composted pine bark was found not to be suitable for growth or for mycorrhization. If the appropriate growth substrate is selected, it is possible to replace the use of chemical fertilisers by inoculation with selected ECM fungi. This results in a significant increase in plant development, and thus ECM fungi can be recommended as a more environmental friendly biotechnological approach to plant management in the nursery.     

Synthesis and biological activity of glycosyl-1H-1,2,3-triazoles

Glycosyl 1,2,3-triazoles with α-d-gluco, β-d-gluco, α-d-galacto, β-d-galacto and β-2-acetamido-2-deoxygluco (GlcNAc) stereochemistry were prepared by reaction of the corresponding azides with vinyl acetate under microwave irradiation. The deprotected glucosyl and galactosyl triazoles did not display inhibitory activity against the tested glycosidases at 1 mM. Of the four fungal glycosidases evaluated, GlcNAc-triazole was found to be hydrolyzed by Talaromyces flavus CCF 2686 β-N-acetylhexosaminidase. β-GlcNAc-triazole was furthermore established to act as a strong ligand of rat and human natural killer cell activating receptors.     

Plio-Pleistocene history of West African Sudanian savanna and the phylogeography of the Praomys daltoni complex (Rodentia): the environment/geography/genetic interplay

Rodents of the Praomys daltoni complex are typical inhabitants of the Sudanian savanna ecosystem in western Africa and represent a suitable model for testing the effects of Quaternary climatic oscillations on extant genetic variation patterns. Phylogeographical analyses of mitochondrial DNA sequences (cytochrome b) across the distribution range of the complex revealed several well‐defined clades that do not support the division of the clade into the two species currently recognized on the basis of morphology, i.e. P. daltoni (Thomas, 1892) and Praomys derooi ( Van der Straeten & Verheyen 1978 ). The observed genetic structure fits the refuge hypothesis, suggesting that only a small number of populations repeatedly survived in distinct forest‐savanna mosaic blocks during the arid phases of the Pleistocene, and then expanded again during moister periods. West African rivers may also have contributed to genetic differentiation, especially by forming barriers after secondary contact of expanding populations. The combination of three types of genetic markers (mtDNA sequences, microsatellite loci, cytogenetic data) provides evidence for the presence of up to three lineages, which most probably represent distinct biological species. Furthermore, incongruence between nuclear and mtDNA markers in some individuals unambiguously points towards a past introgression event. Our results highlight the importance of combining different molecular markers for an accurate interpretation of genetic data.     

A Subset of Cytokinin Two-component Signaling System Plays a Role in Cold Temperature Stress Response in Arabidopsis

A multistep two-component signaling system is established as a key element of cytokinin signaling in Arabidopsis. Here, we provide evidence for a function of the two-component signaling system in cold stress response in Arabidopsis. Cold significantly induced the expression of a subset of A-type ARR genes and of GUS in Pro_ARR7:GUS transgenic Arabidopsis. AHK2 and AHK3 were found to be primarily involved in mediating cold to express A-type ARRs despite cytokinin deficiency. Cold neither significantly induced AHK2 and AHK3 expression nor altered the cytokinin contents of wild type within the 4 h during which the A-type ARR genes exhibited peak expression in response to cold, indicating that cold might induce ARR expression via the AHK2 and AHK3 proteins without alterations in cytokinin levels. The ahk2 ahk3 and ahk3 ahk4 mutants exhibited enhanced freezing tolerance compared with wild type. These ahk double mutants acclimated as efficiently to cold as did wild type. The overexpression of the cold-inducible ARR7 in Arabidopsis resulted in a hypersensitivity response to freezing temperatures under cold-acclimated conditions. The expression of C-repeat/dehydration-responsive element target genes was not affected by ARR7 overexpression as well as in ahk double mutants. By contrast, the arr7 mutants showed increased freezing tolerance. The ahk2 ahk3 and arr7 mutants showed hypersensitive response to abscisic acid (ABA) for germination, whereas ARR7 overexpression lines exhibited insensitive response to ABA. These results suggest that AHK2 and AHK3 and the cold-inducible A-type ARRs play a negative regulatory role in cold stress signaling via inhibition of ABA response, occurring independently of the cold acclimation pathway.     

Determination of doxazosin and verapamil in human serum by fast LC-MS/MS: application to document non-compliance of patients

A rapid and sensitive method using liquid chromatography–tandem mass spectrometry (LC–MS/MS) for simultaneous determination of doxazosin and verapamil in human serum has been developed. Trimipramine-d₃ as an isotopic labelled internal standard was used for quantification. Serum samples were prepared by simple liquid–liquid extraction with mixture of tert butyl methyl ether and ethyl acetate (1:1, v:v). The analytes and internal standard were separated on C18 column using an isocratic elution with 5 mM ammonium formate with 0.02% formic acid and 0.02% formic acid in acetonitrile (55:45, v:v) at a flow rate of 1.1 mL/min. Positive TurboIonSpray mass spectrometry was used with multiple reaction monitoring of the transitions at: m/z 455.3 → 165.2 and 150.2 for verapamil, m/z 452.2 → 344.4 and 247.4 for doxazosin, m/z 298.2 → 103.1 for trimipramine-d₃. Linearity was achieved between 1 and 500 ng/mL (R² ≥ 0.997) for both analytes. An extensive pre-study method validation was carried out in accordance with FDA guidelines. This assay was successfully applied to determine the serum concentrations of doxazosin and verapamil in suspect non-compliance patients.     

The phylogenetic position of <Emphasis Type="Italic">Obolarina dryophila</Emphasis> (Xylariales)

The inconspicuous inner-bark parasite Obolarina dryophila is reported from wood of Quercus petraea and as an endophyte of Salix alba. In addition, viable ascospores of O. dryophila have been found in the gut of the oak bark weevil Gasterocercus depressirostris, suggesting a possible dissemination mechanism for the fungus. A phylogenetic analysis based on three genes (nrDNA, actin, β-tubulin) placed Obolarina inside the genus Biscogniauxia as a close relative of the oak pathogens B. atropunctata and B. mediterranea.     

Synthesis and mass spectrometric fragmentation characteristics of imidazole ribosides-analogs of intermediates of purine de novo synthetic pathway

Two inherited deficiencies have been described in purine de novo synthesis pathway. Both the defects are diagnosed by detecting ribosides--dephosphorylated substrates of the enzymes--in patient's urine. We describe here a synthesis and mass spectrometric fragmentation of ribosides potentially of diagnostic importance for defects in the second part of the pathway. All the species, except 5-amino-4-imidazolesuccinocarboxamideriboside can be synthesized from the commercially available 5-amino-4-imidazolecarboxamideriboside by chemical methods. Fragmentation spectra of the compounds were obtained by the ion trap mass spectrometry. During fragmentation an opening of the imidazole ring was not observed for any of the compounds but loss of its substituents in the form of small molecules (NH3, CO2, CO) is the major route of fragmentation. The ribose moiety cleaves off molecule(s) of water, undergoes a cross-ring cleavage or breaks away as a whole.     

Non-alcoholic fatty liver disease (NAFLD)--a novel common aspect of the metabolic syndrome

Non-alcoholic fatty liver disease (NAFLD) is emerging as one of the most common liver disorders claiming the urgent attention of both medical professionals and the public sphere because of the imminent epidemic of advanced liver injury that appendages epidemic of obesity. Recent research reveals simple triglyceride accumulation in hepatocytes (i.e., liver steatosis) frequently becoming complicated by inflammation (i.e., non-alcoholic steatohepatitis, or NASH) that may progress into more advanced stages of the disease including cirrhosis or, eventually, hepatocellular carcinoma. The exact mechanisms of the progression of NAFLD into overt NASH and advanced disease stages are largely unknown. There is urgent need in terms of both intensive research pursuits and effective practical measures to deal with this common threat.     

Trematodes from Antarctic teleost fishes off Argentine Islands,West Antarctica: molecular and morphological data

Systematic Parasitology - In 2014–2015 and 2019–2021, teleost fishes off Galindez Island (Antarctic Peninsula) were examined for trematodes. Combined morphological and molecular...