Nanoformulation of Lipophilic Osmium Photosensitizers in Liposomes and Micelles as a General Strategy for Improving Reproducibility and Reducing Quenching†

Nanoformulation of an osmium photosensitizer within liposomes and micelles is used to improve the water-solubility of this highly lipophilic molecule. This highlight report describes a recent paper by Cameron, Obaid and McFarland on this topic and discusses the context for this report. Nanoformulation has been explored as a strategy before, but this represents the first usage of this strategy with highly potent metal-based photosensitizers having phototherapeutic indices (PIs) in excess of 10⁴. The nanoformulation strategy is effective due to reducing aggregation and self-quenching of the photosensitizer molecules.     

Ultraviolet Light,Unfolded Protein Response and Autophagy†

The endoplasmic reticulum (ER) plays an important role in the regulation of protein synthesis. Alterations in the folding capacity of the ER induce stress, which activates three ER sensors that mediate the unfolded protein response (UPR). Components of the pathways regulated by these sensors have been shown to regulate autophagy. The last corresponds to a mechanism of self-eating and recycling important for proper cell maintenance. Ultraviolet radiation (UV) is an external damaging stimulus that is known for inducing oxidative stress, and DNA, lipid and protein damage. Many controversies exist regarding the role of UV-inducing ER stress or autophagy. However, a connection between the three of them has not been addressed. In this review, we will discuss the contradictory theories regarding the relationships between UV radiation with the induction of ER stress and autophagy, as well as hypothetic connections between UV, ER stress and autophagy.     

Generation of Singlet Molecular Oxygen by Lipid Hydroperoxides and Nitronium Ion†

Singlet molecular oxygen is a reactive species involved in biological oxidative processes. The major cellular targets of singlet molecular oxygen are unsaturated fatty acids in the membrane, as well as nucleic acids and proteins. The aim of this study was to investigate whether lipids and commercial hydroperoxides generate singlet molecular oxygen, in presence of nitronium and activated nitronium ion. For this purpose, monomol light emitted in the near-infrared region (λ = 1270 nm) was used to monitor singlet molecular oxygen decay in different solvents, with different hydroperoxides and in the presence of azide. Direct measurements of the singlet molecular oxygen spectrum at 1270 nm recorded during the reaction between lipids and commercial hydroperoxides and nitronium ions unequivocally demonstrated the formation of this excited species.     

Photodynamic Inactivation of Bacteria in Ionic Environments Using the Photosensitizer SAPYR and the Chelator Citrate†

Many studies show that photodynamic inactivation (PDI) is a powerful tool for the fight against pathogenic, multiresistant bacteria and the closing of hygiene gaps. However, PDI studies have been frequently performed under standardized in vitro conditions comprising artificial laboratory settings. Under real-life conditions, however, PDI encounters substances like ions, proteins, amino acids and fatty acids, potentially hampering the efficacy of PDI to an unpredictable extent. Thus, we investigated PDI with the phenalene-1-one-based photosensitizer SAPYR against Escherichia coli and Staphylococcus aureus in the presence of calcium or magnesium ions, which are ubiquitous in potential fields of PDI applications like in tap water or on tissue surfaces. The addition of citrate should elucidate the potential as a chelator. The results indicate that PDI is clearly affected by such ubiquitous ions depending on its concentration and the type of bacteria. The application of citrate enhanced PDI, especially for Gram-negative bacteria at certain ionic concentrations (e.g. CaCl₂ or MgCl₂: 7.5 to 75 mmol L⁻¹). Citrate also improved PDI efficacy in tap water (especially for Gram-negative bacteria) and synthetic sweat solution (especially for Gram-positive bacteria). In conclusion, the use of chelating agents like citrate may facilitate the application of PDI under real-life conditions.     

Fruit Tree model for uptake of organic compounds from soil and air†

The current European risk assessment for chemicals considers only tap water, while in reality other beverages play an important role. A good part of beverages are made from fruits, for example apple juice and vine. A mathematical model was developed to predict uptake of neutral organic chemicals from soil and air into fruits. The new fruit tree model considers eight compartments, i.e. two soil compartments, fine roots, thick roots, stem, leaves, fruits, and air. Chemical equilibrium, advective transport in xylem and phloem, diffusive exchange to soil and air and growth dilution are the main processes. The parameterization is for a square-meter of an apple orchard. The model predicts that polar, non-volatile compounds will effectively be transported from soil to fruits, while lipophilic compounds will preferably accumulate from air into fruits. Results from various experiments show no disagreement with the model predictions.     

Structural and Functional Analysis of a Prokaryotic (6-4) Photolyase from the Aquatic Pathogen Vibrio Cholerae†

Photolyases are flavoproteins, which are able to repair UV-induced DNA lesions in a light-dependent manner. According to their substrate, they can be distinguished as CPD- and (6-4) photolyases. While CPD-photolyases repair the predominantly occurring cyclobutane pyrimidine dimer lesion, (6-4) photolyases catalyze the repair of the less prominent (6-4) photoproduct. The subgroup of prokaryotic (6-4) photolyases/FeS-BCP is one of the most ancient types of flavoproteins in the ubiquitously occurring photolyase & cryptochrome superfamily (PCSf). In contrast to canonical photolyases, prokaryotic (6-4) photolyases possess a few particular characteristics, including a lumazine derivative as antenna chromophore besides the catalytically essential flavin adenine dinucleotide as well as an elongated linker region between the N-terminal α/β-domain and the C-terminal all-α-helical domain. Furthermore, they can harbor an additional short subdomain, located at the C-terminus, with a binding site for a [4Fe-4S] cluster. So far, two crystal structures of prokaryotic (6-4) photolyases have been reported. Within this study, we present the high-resolution structure of the prokaryotic (6-4) photolyase from Vibrio cholerae and its spectroscopic characterization in terms of in vitro photoreduction and DNA-repair activity.     

A new triterpene and a saponin from Centella asiatica

A new triterpene and a saponin,named 2α,3β,23-trihydroxyurs-20-en-28-oic acid(1)and 2α,3β,23-trihydroxyurs-20-en-28-oic acid O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl ester(2),have been isolated from the aerial part of Centella asiatica.Their structures were elucidated by spectral methods,including 2D-NMR spectra.     

Gene Cloning and Characterization of a Novel Salt-Tolerant and Glucose-Enhanced β-Glucosidase from a Marine Streptomycete

The gene BglNH encoding a β-glucosidase was cloned from a marine streptomycete. Sequence analysis revealed that BglNH encoded a 456-aa peptide with a calculated mass of 51 kDa. The deduced amino acid sequence of BglNH showed the highest identities of 61 % with known β-glucosidases and contained a catalytic domain which belonged to the glycoside hydrolase family 1. The gene BglNH was expressed in Escherichia coli and the recombinant enzyme (r-BglNH) was purified. The optimum pH and temperature of r-BglNH were pH?6.0 and 45 °C, respectively. The r-BglNH displayed the typical salt-tolerant and glucose-enhanced characteristics. Its activity was remarkably enhanced in the presence of 0.5 M NaCl (rose more than 1.6-fold) and 0.1 M glucose (rose more than 1.4-fold). Moreover, r-BglNH displayed good pH stability and metal tolerance. It remained stable after incubating with buffers from pH?4.0 to 10.0, and most metal ions had no significant inhibition on its activity. These properties indicate that r-BglNH is an ideal candidate for further research and industrial applications.     

First Isolation and Structure Elucidation of GDNT-β-Glu – Tetraether Lipid Fragment from Archaeal Sulfolobus Strains

Due to their special chemical structure, tetraether lipids (TEL) represent essential elements of archaeal membranes, providing these organisms with extraordinary properties. Here we describe the characterization of a newly isolated structural element of the main lipids. The TEL fragment GDNT-β-Glu was isolated from Sulfolobus metallicus and characterized in terms of its chemical structure by NMR- and MS-investigations. The obtained data are dissimilar to analogically derived established structures – in essence, the binding relationships in the polar head group are re-determined and verified. With this work, we provide an important contribution to the structure elucidation of intact TEL also contained in other Sulfolobus strains such as Solfulobus acidocaldarius and Sulfolobus solfataricus.     

Resveratrol and arctigenin production from polydatin and arctiin respectively by a thermostable β-glucosidase from Thermotoga maritima

Abstract

For preparation of resveratrol and arctigenin from peanut hulls and arctium lappa fruits, respectively, a recombinant β-glucosidase (TmBglA) from hyperthermophile Thermotoga maritima was purified and characterized. The hydrolytic activity was the highest at 90?°C and pH 6.2 for arctiin with K_m of 1.61?mM and k_cat of 197.4?s^?1, and 90?°C and 5.8 for polydatin with K_m of 0.38?mM and k_cat of 47.6?s^?1. The enzyme produced 215.4?mg L^?1 resveratrol and 355.7?mg L^?1 arctigenin from 400?mg L^?1 polydatin and 540?mg L^?1 arctiin after 60?min of incubation at 80?°C, with capable of hydrolyzing up to 92.1 and 94.9% of polydatin and arctiin, respectively. The enzymatic hydrolysis of peanut hulls and fructus arctii displayed a conversion yield of 3.8 and 0.33?mg resveratrol and arctigenin per gram of substrate material flour, respectively. Of the reported β-glucosidase, TmBglA exhibited the highest thermostability, k_cat, k_cat/K_m, and conversion productivity for hydrolyzing polydatin and arctiin, and has great potential applications in functional food and medicine production.     

Aluminum electrodeposition from a non-aqueous electrolyte—a combined computational and experimental study

Electrodeposition of aluminum (Al) from an organic non-aqueous electrolyte of ethylbenzene containing aluminum bromide is demonstrated. It is offered as a simple method for the preparation of Al coatings. This work employs distinct electrochemical techniques and explores the effects of the experimental parameters on the kinetics of the process and the quality of the final coatings. The process presented here enables deposition of pure and crystalline Al at room temperature and facilitates the production of uniform Al coatings on various metallic substrates. Morphological studies establish that the growth of Al deposits follows an island mode, and thus, the most noteworthy effect of the substrate over the morphology of the deposits originates from its impact over the nucleation stage, and the density of islands. This study is complemented by theoretical modeling for the adsorption of Al atoms at the different surfaces. Corrosion evaluation determines the dissolution mechanisms of each of the studied substrates in the examined electrolyte. These findings further corroborate the claim that this electrolyte enables the reversible electrodeposition of Al.

     

A New Sesquiterpene and a New Norsesquiterpene from Cacalia deltophylla

A new sesquiterpene and a new norsesquiterpene were isolated from the whole plant of Cacalia deltophylla (Maxim) Mattf. Their structures were elucidated as deltocacalone (1) and deltonorcacalol (2) by spectroscopic methods including 2D NMR.     

An Abietane Diterpene and a Sterol from Fungus Phettinus igniarius

A new abietane diterpene 12-hydroxy-7-oxo-5, 8, 11, 13-tetraene-18, 6-abietanolide, together with a new natural sterol stigmasta-7, 22-diene-3β, 5α, 6α-triol have been isolated from the fruiting body of the fungus Phellinus igniarius. Their structures were elucidated by spectroscopic methods including 2D NMR techniques.     

A New Stigmasterol and a New Eremophilenolide from Ligularia dolichobotrys

A new stigmasterol 3β, 7α, 22-trihydoxystigmast-5-ene (1) and a new eremophilenolide 8α-methoxy-6β-angeloyloxyeremophil-7(1 l)-en-8β, 12-olide-14-oic acid (2) were isolated from Ligularia dolichobotrys Diels. Their structures were deduced on the basis of spectral data.     

Esterification Catalysis by Pyridinium p-Toluenesulfonate Revisited—Modification with a Lipid Chain for Improved Activities and Selectivities

The lipid analogs of pyridinium p-toluenesulfonate (PPTS) were examined for catalysis of the condensation of an equimolar mixture of carboxylic acids and alcohols under mild conditions without removal of water. Although PPTS is a poor catalyst, the introduction of a lipid chain and nitro group significantly improved the activity of PPTS and led to selectivity at suppressing the elimination side reactions of alcohols. 2-Oleamido-5-nitro-pyridinium p-toluenesulfonate (6) is a lead catalyst that promoted various esterification reactions with yields up to 99%.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]     

A New Flavanone and a New Flavanone Glycoside from Scutellaria baicalensis

A new flavanone (2S)-5, 7, 2',5'-tetrahydroxy-flavanone 1 together with a new flavanone glycoside (2S)-5, 7, 2',5'-tetrahydroxy-flavanone 7-O-β-D-glucopyranoside 2, were isolated from the dry roots of Scutellaria baicalensis. Their structures were elucidated on the basis of spectroscopic data.     

A New Triterpenoid Saponin and a New Glycoside from Epigynum aurilum

A new triterpenoid saponin with novel sugar moiety (1), a new trisaccharide derivative (2), as well as a known monosaccharide derivative (3), were isolated from the dried stem of Epigyhum aurilum. The structures of compounds 1 and 2 were determined by MS and NMR spectram analyses.     

A New Flavanone and a New Flavanone Glycoside from ScuteUaria baicalensis

A new flavanone （2S）-5, 7, 2＇, 5＇-tetrahydroxy-flavanone 1 together with a new flavanone glycoside （2S）-5, 7, 2＇, 5＇-tetrahydroxy-flavanone 7-O-13-D-glucopyranoside 2, were isolated from the dry roots of Scutellaria baicalensis. Their structures were elucidated on the basis of spectroscopic data.     

Modeling the Characteristics of a Polyaniline–DNA Film from the Voltammetric Response of the Product of Electropolymerization

Russian Journal of Electrochemistry - The article studies the anodic voltammetric response of polyaniline obtained by electropolymerization of aniline from a 3.7 M sulfuric acid solution in the...