Synthesis of a highly fluorescent N,N‐dimethyl benzylamine–palladium(II) curcuminate complex and its application for determination of trace amounts of water in organic solvents

In this work a new highly fluorescent N,N‐dimethyl benzylamine–palladium(II) yu complex was synthesized by the reaction of [Pd₂{(C,N–C₆H₄CH₂N(CH₃)₂}₂(μ‐OAc)]₂] with curcumin. The structure of the synthesized complex was characterized using Fourier transform infra‐red (FT‐IR) spectroscopy, ¹H nuclear magnetic resonance spectroscopy, and elemental analysis. Fluorescence quantum yield (Φ_F) values of the synthesized complex in dimethyl sulfoxide (DMSO), acetonitrile, ethanol, and methanol were 0.160, 0.104, 0.068, and 0.061, respectively. The fluorescence signal of the complex in the organic solvents was very sensitive to the water content of the organic solvent. The quenching effect of water was used to determine trace amounts of water in the heteroatom‐containing organic solvents (ethanol, methanol, acetonitrile) and redox‐active solvents (DMSO). The linear ranges for determination of water (v/v %) in ethanol, DMSO and acetonitrile were found to be 0.03–14.5, 0.08–13.8, and 0.07–18.8, respectively. Two linear ranges were found for determination of water (v/v %) in methanol (0.1–1.2 and 4.7–25.0). Detection limit (DL) values were calculated to be 0.001, 0.05, 0.004, and 0.01 (v/v %) in ethanol, methanol, acetonitrile, and DMSO, respectively. The proposed method overcomes the problems of the standard Karl Fischer method for determination of water in DMSO. In addition, it gave the best DL value for determination of water in ethanol compared with all published papers to date.     

Regulation of Gdnf expression by retinoic acid in Sertoli cells

Glial cell line‐derived neurotrophic factor (GDNF) and retinoic acid (RA) are two molecules crucial for the regulation of the spermatogonial compartment of the testis. During the cycle of the seminiferous epithelium, their relative concentration oscillates with lower GDNF levels in stages where RA levels are high. It has been recently shown that RA negatively regulates Gdnf expression but the mechanisms behind are so far unknown. Here, we show that RA directly downregulates Gdnf mRNA levels in primary murine Sertoli cells through binding of RARα to a novel DR5‐RARE on Gdnf promoter. Pharmacological inhibition and chromatin immunoprecipitation–quantitative polymerase chain reaction analysis suggested that the underlying mechanism involved histone deacetylase activity and epigenetic repression of Gdnf promoter upon RA treatment.     

Microbial carbon limitation: The need for integrating microorganisms into our understanding of ecosystem carbon cycling

Numerous studies have demonstrated that fertilization with nutrients such as nitrogen, phosphorus, and potassium increases plant productivity in both natural and managed ecosystems, demonstrating that primary productivity is nutrient limited in most terrestrial ecosystems. In contrast, it has been demonstrated that heterotrophic microbial communities in soil are primarily limited by organic carbon or energy. While this concept of contrasting limitations, that is, microbial carbon and plant nutrient limitation, is based on strong evidence that we review in this paper, it is often ignored in discussions of ecosystem response to global environment changes. The plant‐centric perspective has equated plant nutrient limitations with those of whole ecosystems, thereby ignoring the important role of the heterotrophs responsible for soil decomposition in driving ecosystem carbon storage. To truly integrate carbon and nutrient cycles in ecosystem science, we must account for the fact that while plant productivity may be nutrient limited, the secondary productivity by heterotrophic communities is inherently carbon limited. Ecosystem carbon cycling integrates the independent physiological responses of its individual components, as well as tightly coupled exchanges between autotrophs and heterotrophs. To the extent that the interacting autotrophic and heterotrophic processes are controlled by organisms that are limited by nutrient versus carbon accessibility, respectively, we propose that ecosystems by definition cannot be ‘limited’ by nutrients or carbon alone. Here, we outline how models aimed at predicting non‐steady state ecosystem responses over time can benefit from dissecting ecosystems into the organismal components and their inherent limitations to better represent plant–microbe interactions in coupled carbon and nutrient models.     

Interaction of <i>Acaena elongata</i> L. with Arbuscular Mycorrhizal Fungi under Phosphorus Limitation Conditions in a Temperate Forest

The aim of this study was to analyze the performance of Acaena elongata colonized by arbuscular mycorrhizal fungi (AMF) to different phosphorus (P) concentrations, as a measure of AMF dependency. A. elongata, is a species from soils where P availability is limited, such as temperate forests. Our research questions were: 1) How do different P concentrations affect the AMF association in Acaena elongata, and 2) How does the AMF association influence A. elongata’s growth under different P concentrations? A. elongata’s growth, P content in plant tissue, AMF colonization and dependency were measured under four P concentrations: control (0 g P kg⁻¹ ), low (0.05 g P kg⁻¹ ), intermediate (0.2 g P kg⁻¹ ) and high (2 g P kg⁻¹ ) in different harvests. A complete randomized block design was applied. A. elongata’s growth was higher under -AMF in intermediate and high P concentrations, and the lowest growth corresponded to +AMF in the low and intermediate P concentration. We observed a negative effect on the root biomass under +AMF in intermediate P concentration, while the P concentration had a positive effect on the leaf area ratio. The AMF colonization in A. elongata decreased in the highest P concentration and it was favored under intermediate P concentration; while the low and the high concentrations generated a cost-benefit imbalance. Our results suggest that the performance of some plant species in soils with low P availability may not be favored by their association with AMF, but a synergy between AMF and intermediate P concentrations might drive A. elongata’s growth.     

Ixodes ricinus and Borrelia burgdorferi sensu lato in the Royal Parks of London,UK

Experimental and Applied Acarology - Assessing the risk of tick-borne disease in areas with high visitor numbers is important from a public health perspective. Evidence suggests that tick presence,...     

Toxoplasma gondii profilin and tachyzoites RH strain may manipulate autophagy via downregulating Atg5 and Atg12 and upregulating Atg7

Molecular Biology Reports - Autophagy process is an important defense mechanism against intracellular infection. This process plays a critical role in limiting the development of Toxoplasma gondii....