Key taste components in two wild edible Boletus mushrooms using widely targeted metabolomics

Compounds from wild edible mushrooms has been reported to exert biological activities and contribute to the different flavors of mushrooms in our diet. Wild edible Boletus mushrooms are popular in Southwest China. In this study, we performed ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) based on widely targeted metabolomics analysis to identify key components. A total of 194 metabolites (113 upregulated, 81 downregulated) divided into 11 groups (49 metabolites in group lipids, 34 in amino acids and derivatives, 30 in organic acids, 18 in phenolic acids, 16 in nucleotides and derivatives, 13 in alkaloids, 6 in flavonoids, 3 in lignans and coumarins, 3 in tannins, 2 in terpenoids, and 20 in others) were found among Boletus bainiugan compared with B. subsplendidus. Through clustering analysis, principal component analysis (PCA), and orthogonal signal correction and partial least squares-discriminant analysis (OPLS-DA), different metabolites from fruiting bodies were clearly identified. Significant differences were observed in the metabolites between Boletus bainiugan and B. subsplendidus. These metabolites are involved in important biological functions. Our results provide new insights into important metabolites and theoretical basis for the taste difference of two wild edible Boletus mushrooms.     

Extended Producer Responsibility in Thailand

Waste electrical and electronic equipment (WEEE) sheds light on the dimmer side of production and consumption patterns in modern societies. The rapid increase in its quantity and complexity contribute to the challenges it poses to solid waste management systems. Several members of the Organisation for Economic Co‐operation and Development (OECD) have relied on the principle of extended producer responsibility (EPR) to tackle the issue, with varying degrees of success. Several non‐OECD countries, including Thailand, are now developing WEEE programs and are looking for lessons from these first movers. This case study aims to provide an understanding both of this context and of the EPR program for WEEE proposed for Thailand. It finds that EPR mechanisms in general, and the proposed buy‐back system financed by product fees in Thailand in particular, have a strong potential to consolidate WEEE collection for the formal recycling sector by offering end users monetary incentives. On the negative side, this is an expensive combination of policy instruments, and the institutional design of the governmental fund is rigid. The policy proposal also contains no mechanism for product redesign—one of the objectives in the national WEEE strategy. This article suggests that the effectiveness of the policy might benefit from more flexibility at the compliance scheme level, in order to lessen the monopoly of the governmental fund, as well as the introduction of differentiated fees to promote environmentally friendly products.     

Randomness and Order in a Forest with Trees in Rows-a Case Study

The correlations between intertree distances and stem volumina of trees in an artificial pine wood with trees in rows are studied. Several stochastic models are suggested, and methods of the theory of random measures are used. A method for estimating the produce of woods of the type considered is suggested.     

Saldanha Bay,South Africa: recovery of Gracilaria verrucosa (Gracilariales,Rhodophyta)

Since World War II the greater Saldanha Bay lagoon system, South Africa, has been an important Gracilaria producer. Two agar factories, built in the 1960's, used Gracilaria from Saldanha Bay as their raw material. In the early 1970's the industry was destroyed as a result of dredging and marine construction operations to establish a harbor in the bay for loading ore. These environmental changes destroyed stocks and prevented the previously significant beachings of the seaweed from occurring. After a few years of no or very low commercial production, the resource slowly started to recover. The size of Gracilaria drifts increased over the following eight years to approximately one-third of the original output. This trend seems to continue. Although the stocks and resultant drifts are unlikely to recover fully to their original quantity, current production is already sufficient to ensure re-establishment of a seaweed industry in Saldanha Bay. This could have considerable socio-economic impact on the area.     

Synthesis and antifungal activity of ASP9726, a novel echinocandin with potent Aspergillus hyphal growth inhibition

The synthesis and antifungal activity of ASP9726, a novel echinocandin with potent Aspergillus hyphal growth inhibition and significantly improved MIC against Candida parapsilosis and echinocandin resistant-Candida is described.     

Thermohaemolysis of human erythrocytes in sucrose containing isotonic media

1. 1.|The thermohaemolysis of human erythrocytes in NaCl/sucrose isotonic media can be best accounted for in terms of the colloid-osmotic theory of haemolysis.

2. 2.|The thermohaemolysis in NaCl saline was preceded by leakage of K⁺ and cell swelling. If the inner oncotic osmoactivity was balanced with external sucrose the cells progressively shrinked losing K⁺, but the haemolysis was strongly reduced.

3. 3.|Time dependence of the shrinking of cells and one-step resealed ghosts suspended in isotonic 60 mOsm NaCl/sucrose media was studied between 50 and 58°C.

4. 4.|After a lag period for cells only, this shrinking proceeded with apparently constant rate for cells and ghosts.

5. 5.|The rate constant of shrinking for cells and ghosts obeys the Arrhenius relation, giving the value of 250 ± 15 kJ/mol for the activation energy of shrinking in both cases. This is also the case for the activation energy of the membrane ion permeability constant.

6. 6.|These results are consistent with the thermal inactivation of membrane associated protein(s) acting as a trigger for the ion permeability barrier disturbance.

7. 7.|The mid-point temperature for these membrane events was about 61°C.

SP3-Enabled Rapid and High Coverage Chemoproteomic Identification of Cell-State–Dependent Redox-Sensitive Cysteines

Proteinaceous cysteine residues act as privileged sensors of oxidative stress. As reactive oxygen and nitrogen species have been implicated in numerous pathophysiological processes, deciphering which cysteines are sensitive to oxidative modification and the specific nature of these modifications is essential to understanding protein and cellular function in health and disease. While established mass spectrometry-based proteomic platforms have improved our understanding of the redox proteome, the widespread adoption of these methods is often hindered by complex sample preparation workflows, prohibitive cost of isotopic labeling reagents, and requirements for custom data analysis workflows. Here, we present the SP3-Rox redox proteomics method that combines tailored low cost isotopically labeled capture reagents with SP3 sample cleanup to achieve high throughput and high coverage proteome-wide identification of redox-sensitive cysteines. By implementing a customized workflow in the free FragPipe computational pipeline, we achieve accurate MS1-based quantitation, including for peptides containing multiple cysteine residues. Application of the SP3-Rox method to cellular proteomes identified cysteines sensitive to the oxidative stressor GSNO and cysteine oxidation state changes that occur during T cell activation.     

Chelation of hypocrellin B with zinc ions with electron paramagnetic resonance (EPR) evidence of the photodynamic activity of the resulting chelate

Hypocrellin B (HB), a perylenequinone derivative, is an efficient phototherapeutic agent. The chelation of HB with Zinc ions (Zn²⁺) results in a metal chelate (Zn-HB) which exhibits considerable absorption (λ_max = 612nm) in the phototherapeutic window. The structure of this chelate has been characterized by UV-Vis, IR and mass spectra. The redox potentials of the Zn-HB chelate were E_ox = +1.1V (vs. SCE) and E_re = -0.7V (vs. SCE) as measured using the circle volt curve. The quantum yield of singlet oxygen generated by the Zn-HB chelate was 0.86, which both the electron spin trap (EPR) method and the chemical trap method show to be about 0.1 higher than that of its parent compound HB. In irradiated oxygen-saturated solutions of Zn-HB chelate, superoxide radical anions and hydroxyl radicals were detected by EPR spectroscopy using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the spin-trapping agent.     

Evidence for cooperative effects in the binding of polyvalent metal ions to pure phosphatidylcholine bilayer vesicle surfaces

An internal NMR monitor for the study of lanthanide ion (Ln³⁺) binding to phospholipid bilayer membranes has been developed. The dimethylphosphate anion, DMP^?, forms labile complexes with Ln³⁺ in aqueous solution and in solutions also containing bilayer dispersions. The hyperfine shift in the DMP^? resonance induced by Pr³⁺ ions has been used to determine the overall thermodynamic formation constants for the Pr(DMP)²⁺ and Pr(DMP)₂⁺ complexes: 81 (M^?1) and 349 (M^?2) at 52°C; the limiting hyperfine shift (³¹P) at 52°C is 91.5 ppm downfield. These parameters, applied to the observed DMP^? hyperfine shift in the presence of the membrane, establish both the free Pr³⁺ concentration and the amount of Pr³⁺ bound to the phospholipid surface. Extensive data for the binding of Pr³⁺ to the outer surfaces of sonicated vesicles yield a limiting hyperfine shift per Pr³⁺ of 181.6 ppm downfield for the dipalmitoylphosphatidylcholine ³¹P resonance at 52°C, clearly demonstrating that the binding stoichiometry is two DPPCs per Pr³⁺. A Hill analysis indicates that the binding data are more anti-cooperative than a realistic Langmuir isotherm, yet more cooperative than a Stern isotherm incorporating electrostatic considerations at the Debye-Hückel level. Fittings to specific models lead to a cooperative model in which tense (T) sites, with low affinity for Pr³⁺, present in the absence of metal ions, quickly give way to relaxed (R) sites (two DPPCs per site), with much higher affinity for Pr³⁺, as the amount of Pr³⁺ bound to the surface increases. The intrinsic equilibrium constants for the binding of Pr³⁺ to DPPC vesicles are 2 M^?1 and 3 000 M^?1 for the T and R sites, respectively, at 52°C. The distribution coefficient between these sites ([R]/[T]) in the absence of Ln³⁺ is 0.14 at 52°C. We picture the binding site conversion as a head-group conformational change involving mostly the choline moiety. Sketchy results for binding on the inside vesicle surface indicate that the overall affinity for Pr³⁺ is significantly greater and suggest that the site stoichiometry may be different.