In Vitro Fermentation of Animal and Plant Protein Isolates by the Human Gut Microbiota Under High and Low Carbohydrate Conditions.

Scope: There is a lack of research comparing how different protein isolates influence the microbiome, especially when carbohydrate (CHO) availability is varied. The objective is to determine changes in gut microbiota composition and function during fermentation of digested protein isolates under high and low CHO conditions.

Methods And Results: Protein isolates from beef, egg white, milk, pea, and soy are subjected to in vitro digestion and fermentation with human fecal microbiota.

Chiral π-Conjugated Double Helical Aminyl Diradical with the Triplet Ground State.

We report a neutral high-spin diradical of chiral -symmetric bis[5]diazahelicene with Δ ≈ 0.4 kcal mol, as determined by EPR spectroscopy/SQUID magnetometry. The diradical is the most persistent among all high-spin aminyl radicals reported to date by a factor of 20, with a half-life of up to 6 days in 2-MeTHF at room temperature.

Postsynthetic Modification of the Nonanuclear Node in a Zirconium Metal-Organic Framework for Photocatalytic Oxidation of Hydrocarbons.

Heterogeneous catalysis plays an indispensable role in chemical production and energy conversion. Incorporation of transition metals into metal oxides and zeolites is a common strategy to fine-tune the activity and selectivity of the resulting solid catalysts, as either the active center or promotor. Studying the underlying mechanism is however challenging.

Information-Rich, Dual-Function C/H-Isotopic Crosstalk NMR Assay for Human Serine Racemase (hSR) Provides a PLP-Enzyme "Partitioning Fingerprint" and Reveals Disparate Chemotypes for hSR Inhibition.

The first dual-function assay for human serine racemase (hSR), the only bona fide racemase in human biology, is reported. The hSR racemization function is essential for neuronal signaling, as the product, d-serine (d-Ser), is a potent -methyl d-aspartate (NMDA) coagonist, important for learning and memory, with dysfunctional d-Ser-signaling being observed in some neuronal disorders. The second hSR function is β-elimination and gives pyruvate; this activity is elevated in colorectal cancer.

Human Serum Alters the Metabolism and Antibiotic Susceptibility of .

is a common source of hospital-acquired bacterial infections, where the emergence of antibiotic resistance is a serious human health concern. Most investigations into virulence and antibiotic resistance have relied on cultivation conditions and optimized media formulations. However, can survive and adapt to a hostile host environment or antibiotic treatments by rapidly adjusting its metabolic activity.

Evidence for Proline Catabolic Enzymes in the Metabolism of Thiazolidine Carboxylates.

Thiazolidine carboxylates such as thiazolidine-4-carboxylate (T4C) and thiazolidine-2-carboxylate (T2C) are naturally occurring sulfur analogues of proline. These compounds have been observed to have both beneficial and toxic effects in cells. Given that proline dehydrogenase has been proposed to be a key enzyme in the oxidative metabolism of thioprolines, we characterized T4C and T2C as substrates of proline catabolic enzymes using proline utilization A (PutA), which is a bifunctional enzyme with proline dehydrogenase (PRODH) and l-glutamate-γ-semialdehyde dehydrogenase (GSALDH) activities.

Metabolic profiling of historical and modern wheat cultivars using proton nuclear magnetic resonance spectroscopy.

To determine changes in the grain components between historical and modern wheat (Triticum aestivum L.) cultivars, wholemeal flours from 19 wheat cultivars and 2 landraces released or introduced between 1870 and 2013 and grown over two crop years were extracted using hydroalcoholic solution and analyzed using one dimensional H NMR spectral profiling. Grain yield, grain volume weight (GVW), and grain protein concentration were also measured.

Cautionary Tale of Using Tris(alkyl)phosphine Reducing Agents with NAD-Dependent Enzymes.

Protein biochemistry protocols typically include disulfide bond reducing agents to guard against unwanted thiol oxidation and protein aggregation. Commonly used disulfide bond reducing agents include dithiothreitol, β-mercaptoethanol, glutathione, and the tris(alkyl)phosphine compounds tris(2-carboxyethyl)phosphine (TCEP) and tris(3-hydroxypropyl)phosphine (THPP). While studying the catalytic activity of the NAD(P)H-dependent enzyme Δ-pyrroline-5-carboxylate reductase, we unexpectedly observed a rapid non-enzymatic chemical reaction between NAD and the reducing agents TCEP and THPP.

Identification of the Biosynthetic Gene Cluster for the anti-MRSA Lysocins through Gene Cluster Activation Using Strong Promoters of Housekeeping Genes and Production of New Analogs in sp. 3655.

The Gram-negative gliding bacteria represent a new and rich source for bioactive natural products. In an effort to discover new antibiotics, we found a cryptic biosynthetic gene cluster (BGC) in sp. 3655 that shared a high similarity with the putative lysocin BGC identified previously from sp.

Phosphorus NMR and Its Application to Metabolomics.

Stable isotopes are routinely employed by NMR metabolomics to highlight specific metabolic processes and to monitor pathway flux. C-carbon and N-nitrogen labeled nutrients are convenient sources of isotope tracers and are commonly added as supplements to a variety of biological systems ranging from cell cultures to animal models. Unlike C and N, P-phosphorus is a naturally abundant and NMR active isotope that does not require an external supplemental source.

Facile access to functionalized chiral secondary benzylic boronic esters catalytic asymmetric hydroboration.

Allylic and homoallylic phosphonates bearing an aryl or heteroaryl substituent at the γ- or δ-position undergo rhodium-catalyzed asymmetric hydroboration by pinacolborane to give functionalized chiral secondary benzylic boronic esters in yields up to 86% and enantiomer ratios up to 99 : 1. Compared to minimally-functionalized terminal and 1,1-disubstituted vinyl arenes, there are relatively few reports of efficient catalytic asymmetric hydroboration (CAHB) of more highly functionalized internal alkenes. Phosphonate substrates bearing a variety of common heterocyclic ring systems, including furan, indole, pyrrole and thiophene derivatives, as well as those bearing basic nitrogen substituents (, morpholine and pyrazine) are tolerated, although donor substituents positioned in close proximity of the alkene can influence the course of the reaction.

Preparation of Some Homologous TEMPO Nitroxides and Oxoammonium Salts; Notes on the NMR Spectroscopy of Nitroxide Free Radicals; Observed Radical Nature of Oxoammonium Salt Solutions Containing Trace Amounts of Corresponding Nitroxides in an Equilibrium Relationship.

Three new homologous TEMPO oxoammonium salts and three homologous nitroxide radicals have been prepared and characterized. The oxidation properties of the salts have been explored. The direct C NMR and EPR spectra of the nitroxide free radicals and the oxoammonium salts, along with TEMPO and its oxoammonium salt, have been successfully measured with little peak broadening of the NMR signals.

Thiophene-Based Double Helices: Syntheses, X-ray Structures, and Chiroptical Properties.

We demonstrate facile and efficient construction of conjugated double helical ladder oligomers from the saddle-shaped cyclooctatetrathiophene (COTh) building blocks. The key step involves deprotonation of tetra[3,4]thienylene (β,β-COTh) with n-BuLi which displays remarkably high ipsilateral selectivity. Three racemic double helical ladder oligomers, rac-DH-1, rac-DH-2, and rac-DH-3, containing two, three, and five COTh annelated moieties are efficiently synthesized by diastereoselective coupling of the racemic precursors.

Effect of 17β-estradiol on stability and mobility of TiO2 rutile nanoparticles.

Contaminants including titanium dioxide nanoparticles (n-TiO2), as well as organic wastewater contaminants (OWCs), have been detected in wastewater treatment plant effluents, however, no information is yet available on how OWCs may modify the surface properties of TiO2 nanoparticles, or influence their stability in water and subsequent mobility in porous media. In this study, 17β-estradiol (E2) was chosen as a representative OWC to investigate the interaction between OWCs and n-TiO2. Batch and kinetic sorption experiments and Fourier Transform Infrared (FTIR) Spectrometer measurements confirmed that E2 was quickly sorbed onto the surface of n-TiO2 aggregates in water.

Large-scale solution synthesis of narrow graphene nanoribbons.

According to theoretical studies, narrow graphene nanoribbons with atomically precise armchair edges and widths of <2 nm have a bandgap comparable to that in silicon (1.1 eV), which makes them potentially promising for logic applications. Different top-down fabrication approaches typically yield ribbons with width >10 nm and have limited control over their edge structure.

Stability of N-glycosidic bond of (5'S)-8,5'-cyclo-2'-deoxyguanosine.

8,5'-Cyclopurine deoxynucleosides are unique tandem lesions containing an additional covalent bond between the base and the sugar. These mutagenic and genotoxic lesions are repaired only by nucleotide excision repair. The N-glycosidic (or C1'-N9) bond of 2'-deoxyguanosine (dG) derivatives is usually susceptible to acid hydrolysis, but even after cleavage of this bond of the cyclopurine lesions, the base would remain attached to the sugar.

Toward a formal synthesis of laureatin: unexpected rearrangements involving cyclic ether nucleophiles.

Laureatin, a metabolite of the red algae Laurencia nipponica, has shown potent activity as a mosquito larvicide. The two previously published syntheses of laureatin involved an initial preparation of the 8-membered cyclic ether, followed by formation of the oxetane ring. Our strategy was the reverse, i.

meso-Tetrakis(pentafluorophenyl)porphyrin-derived chromene-annulated chlorins.

The synthesis of mono- and bis-chromene-annulated meso-(pentafluorophenyl)chlorins from meso-tetrakis(pentafluorophenyl)porphyrins by an OsO(4)-mediated dihydroxylation reaction, followed by an intramolecular nucleophilic aromatic substitution reaction, is described. The reaction sequence is applicable to the free base systems as well as their Zn(II), Ni(II), Pd(II), and Pt(II) complexes. The optical properties (UV-vis and fluorescence spectra) of the (metallo)chlorin-like chromophores that possess slightly red-shifted optical spectra compared to the corresponding 2,3-dihydroxychlorins are reported.

Access to oxetane-containing psico-nucleosides from 2-methyleneoxetanes: a role for neighboring group participation?

The first psico-oxetanocin analogue of the powerful antiviral natural product, oxetanocin A, has been readily synthesized from cis-2-butene-1,4-diol. Key 2-methyleneoxetane precursors were derived from β-lactones prepared by the carbonylation of epoxides. F(+)-mediated nucleobase incorporation provided the corresponding nucleosides in good yield but with low diastereoselectivity.

Polymer-mediated cyclodehydration of alditols and ketohexoses.

The polymer PEDOT(+) (1 or 2) mediates a cyclodehydration reaction with alditols 3, 5, 7, 9, in hydrocarbon solvents, to give cyclic ethers 4, 6, 8, or 10, respectively, in high yield with a trivial isolation protocol. Polymers 1 or 2 also mediate the cyclodehydration of ketohexoses such as d-fructose, but not aldohexoses, to the important industrial intermediate 5-hydroxymethylfurfural (17), under milder conditions when compared to reactions mediated by mineral acids. A cascade reaction with ketohexoses is observed in toluene via cyclodehydration followed by Friedel-Crafts alkylation of the initially formed benzylic alcohol to give 16.

Synthesis of 3-guaninyl- and 3-adeninyl-5-hydroxymethyl-2-pyrrolidinone nucleosides.

L- and D-glutamic acids, as well as trans-4-hydroxy-L-proline, are converted to the corresponding 3-guaninyl-5-hydroxymethyl-2-pyrrolidinone (4) or 3-adeninyl-5-hydroxymethyl-2-pyrrolidinone (5) nucleoside analog. The protecting group used to block the lactam nitrogen in key intermediates has a significant effect on the diastereoselectivity of the coupling reaction with adenine or guanine.

Synthesis of Oxazolidinone and Tosyl Enamines by Tertiary Amine Catalysis.

A procedure for the synthesis of oxazolidinone and tosyl enamines is reported. Alkynoyl oxazolidinones and tosyl imides undergo reaction to form enamines in the presence of catalytic amounts of tertiary amines. The data suggest that an amide anion is formed during the reaction, which undergoes conjugate addition to form the final product.