A systematic evaluation of protocols for a proteomics analysis of (lyophilized) fruit tissues

This study represents a systematic evaluation of protocols for protein extraction and cleanup for fruit proteomic analysis. Procedures were optimized using pooled lyophilized banana fruit pulp, which is known to be particularly tricky due to high concentrations of soluble polysaccharides, phenolics, and other substances that interfere with protein extraction and purification. A total of 18 combinations of three protein extraction procedures (SDS‐based, Triton X‐100‐based, and phenol‐based), three protein precipitating agents (ammonium acetate/methanol, TCA/acetone, and acetone), and two resolubilization buffers (classical Rabilloud and the so‐called R2D2) were compared for total protein yields and efficiency of recovery. The results demonstrate that while losses in total recovered protein are unavoidable, the degree of these losses depends on the method combinations used. Combinations based on buffer‐saturated phenol always gave the highest yields, and overall recovery and purity was highest when acetone was combined with the R2D2 buffer for protein purification and concentration. Comparative 2D‐PAGE analysis confirmed that this method combination produced high‐quality and reproducible gels and the largest numbers of spots per gel. The usefulness of this methodology was demonstrated on ripe fruits from several other species and shown to give excellent results.     

Novel and unusual triterpene from Black Cohosh. Determination of structure of 9,10-seco-9,19-cyclolanostane xyloside (cimipodocarpaside) by NMR, IR and Raman spectroscopy and DFT calculations

A new triterpene xyloside, designated cimipodocarpaside was isolated from a Black Cohosh (Actea racemosa L.) extract and its structure was elucidated by means of 1H, 13C NMR, IR and Raman spectroscopy supported by B3LYP/6-31G** calculations. The vibrational spectra were interpreted using the PED analysis of 273 fundamentals. Its structure comprises four condensed rings A-D which are 6, 7, 6, and 5-membered, respectively. An oxiirane ring is located in the side chain and a xylose moiety is attached to the A-ring. Comparison of the experimental 13C NMR data with the theoretical chemical shifts of 24S- and 24R-cimipodocarpaside isomers revealed that the isolated compound has the 24S-configuration. Combined spectroscopic and computational studies enabled the determination of the structure of cimipodocarpaside as (24S)-3β-hydroxy-24,25-oxiirane-16,23-dione-9,10-seco-9,19-cyclolanost-7(8),9(11),10(19)-trien-3-O-β-D-xylopyranoside. Triterpenes with 7-membered ring were thus far isolated from only Actea podocarpa DC. plants. This is the first report on the isolation of such a compound from Black Cohosh.     

Natural extensions and profinite completions of algebras

This paper investigates profinite completions of residually finite algebras, drawing on ideas from the theory of natural dualities. Given a class \({\mathcal{A} = \mathbb{ISP}(\mathcal{M})}\), where \({\mathcal{M}}\) is a set, not necessarily finite, of finite algebras, it is shown that each \({{\bf A} \in \mathcal{A}}\) embeds as a topologically dense subalgebra of a topological algebra \({n_{\mathcal{A}}({\bf A})}\) (its natural extension), and that \({n_{\mathcal{A}}({\bf A})}\) is isomorphic, topologically and algebraically, to the profinite completion of A. In addition it is shown how the natural extension may be concretely described as a certain family of relation-preserving maps; in the special case that \({\mathcal{M}}\) is finite and \({\mathcal{A}}\) possesses a single-sorted or multisorted natural duality, the relations to be preserved can be taken to be those belonging to a dualising set. For an algebra belonging to a finitely generated variety of lattice-based algebras, it is known that the profinite completion coincides with the canonical extension. In this situation the natural extension provides a new concrete realisation of the canonical extension, generalising the well-known representation of the canonical extension of a bounded distributive lattice as the lattice of up-sets of the underlying ordered set of its Priestley dual. The paper concludes with a survey of classes of algebras to which the main theorems do, and do not, apply.     

Catalytic enamines from dialkylamide-dialkylacetals

The formation of a transient enamine derived from DMF-DMA provides an effective alternative to the harsh conditions normally required for the nucleophilic addition of base-activated methylene compounds to a carbonyl group. Organocatalysts formed from dialkylamide-dialkylacetals in this manner may provide extensive synthetic utility for a number of well-established reactions in which the formation of enolates and enamines has been employed.     

An Electrolytic Zn–MnO2 Battery for High‐Voltage and Scalable Energy Storage

Zinc‐based electrochemistry is attracting significant attention for practical energy storage owing to its uniqueness in terms of low cost and high safety. However, the grid‐scale application is plagued by limited output voltage and inadequate energy density when compared with more conventional Li‐ion batteries. Herein, we propose a latent high‐voltage MnO₂ electrolysis process in a conventional Zn‐ion battery, and report a new electrolytic Zn–MnO₂ system, via enabled proton and electron dynamics, that maximizes the electrolysis process. Compared with other Zn‐based electrochemical devices, this new electrolytic Zn–MnO₂ battery has a record‐high output voltage of 1.95 V and an imposing gravimetric capacity of about 570 mAh g^?1, together with a record energy density of approximately 409 Wh kg^?1 when both anode and cathode active materials are taken into consideration. The cost was conservatively estimated at <US$ 10 per kWh. This result opens a new opportunity for the development of Zn‐based batteries, and should be of immediate benefit for low‐cost practical energy storage and grid‐scale applications.     

Crosslinking Allosteric Sites on the Nucleosome

Targeting defined histone protein sites in chromatin is an emerging therapeutic approach that can potentially be enhanced by allosteric effects within the nucleosome. Here we characterized a novel hetero‐bimetallic compound with a design based on a nucleosomal allostery effect observed earlier for two unrelated drugs—the Ru^II antimetastasis/antitumor RAPTA‐T and the Au^I anti‐arthritic auranofin. The Ru^II moiety binds specifically to two H2A glutamate residues on the nucleosome acidic patch, allosterically triggering a cascade of structural changes that promote binding of the Au^I moiety to selective histidine residues on H3, resulting in cross‐linking sites that are over 35 Å distant. By tethering the H2A‐H2B dimers to the H3‐H4 tetramer, the hetero‐bimetallic compound significantly increases stability of the nucleosome, illustrating its utility as a site‐selective cross‐linking agent.     

Negative Charging of Transition‐Metal Phosphides via Strong Electronic Coupling for Destabilization of Alkaline Water

Heterogeneous electrocatalysis typically involves charge transfer between surface active sites and adsorbed species. Therefore, modulating the surface charge state of an electrocatalyst can be used to enhance performance. A series of negatively charged transition‐metal (Fe, Co, Ni, Cu,and NiCo) phosphides were fabricated by designing strong electronic coupling with hydr(oxy)oxides formed in situ. Physicochemical characterizations, together with DFT computations, demonstrate that strong electronic coupling renders transition‐metal phosphides negatively charged. This facilitates destabilization of alkaline water adsorption and dissociation to result in significantly improved H₂ evolution. Negatively charged Ni₂P/nickel hydr(oxy)oxide for example exhibits a significantly low overpotential of 138 mV at 100 mA cm^?2, superior to that without strong electronic coupling and also commercial Pt/C.