Selected Species of the Cucurbitaceae Family Used in Mexico for the Treatment of Diabetes Mellitus

In Mexico, Diabetes mellitus (DM) is a serious health problem, and although the current pharmacological treatments for DM such as insulin and oral hypoglycemics are available, the Mexican population continues to use medicinal plants in the treatment of DM. The antidiabetic properties of the plant species that belong to the Cucurbitaceae family has already been recognized worldwide. Since Mexico is one of the most important centers of diversity of Cucurbitaceae, the present work contributes to the review of the most used species of Cucurbitaceae in the treatment of DM in Mexico. The reviewed species (Cucurbita ficifolia, C. maxima, C. moschata, C. pepo, Ibervillea sonorae, Sechium edule, Citrullus lanatus, Cucumis melo, and C. sativus) revealed that the antidiabetic effects exerted are effective in a number of mechanisms involved in the complex pathogenesis of DM: hypoglycemic, antioxidant, anti-inflammatory, anti-obesity, protective effects on diverse organs and cells, as well as in the control of dyslipidemias; furthermore, the select species of the Cucurbitaceae family could also be essential components of diets for the control of DM in patients with the disease. Thus, the Cucurbitaceae species selected in the present work represent a source of antidiabetic agents that perhaps establish the bases for novel clinical treatments.     

Validation of a Reference Gene (BdFIM) for Quantifying Transgene Copy Numbers in Brachypodium distachyon by Real-Time PCR

Brachypodium distachyon has been proposed as a new model system for gramineous plants with a sequenced genome and an efficient transformation system. Many transgenic B. distachyon plants have been generated in recent years. To develop a reliable fast method for detecting transgenic B. distachyon and quantifying its transgene copy numbers, a species-specific reference gene is of great priority to be validated both in qualitative PCR and quantitative real-time PCR detection. In this study, we first proved that the BdFIM (B. distachyon fimbrin-like protein) gene is a suitable reference gene in qualitative PCR and quantitative real-time PCR for B. distachyon. Fourteen different B. distachyon varieties were tested by both qualitative and quantitative PCRs, and identical amplification products of BdFIM were obtained with all of them, while no amplification products were observed with samples from 14 other plant species, suggesting that BdFIM gene was specific to B. distachyon. The results of Southern blot analysis revealed that the BdFIM gene was low copy number in seven tested B. distachyon varieties. In conclusion, the BdFIM gene can be used as a reference gene, since it had species specificity, low heterogeneity, and low copy number among the tested B. distachyon varieties. Furthermore, the copy number of inserted sequences from transgenic B. distachyon obtained by real-time PCR methods and Southern blot confirmed that the BdFIM gene was an applicable reference gene in B. distachyon.     

Water solubility in calcium aluminosilicate glasses investigated by first principles techniques

First-principles techniques have been employed to study the reactivity of water into a calcium aluminosilicate glass. In addition to the well known hydrolysis reactions Si-O-Si+H₂O→Si-OH+Si-OH and Si-O-Al+H₂O→Si-OH+Al-OH, a peculiar mechanism is found, leading to the formation of an AlO₃-H₂O entity and the breaking of Al-O-Si bond. In the glass bulk, most of the hydrolysis reactions are endothermic. Only a few regular sites are found reactive (i.e. in association with an exothermic reaction), and in that case, the hydrolysis reaction leads to a decrease of the local disorder in the amorphous vitreous network. Afterwards, we suggest that ionic charge compensators transform into network modifiers when hydrolysis occurs, according to a global process firstly suggested by Burnham in 1975. Our theoretical computations provide a more general model of the first hydrolysis steps that could help to understand experimental data and water speciation in glasses.     

Kinetics and mechanism of the liquid-phase oxidation of tert-butyl phenylacetate

The oxidation of tert-butyl phenylacetate in ortho-dichlorobenzene at 140°C occurs with short chains. The primary nonperoxide reaction products (tert-butyl α-hydroxyphenylacetate, tert-butyl α-oxophenylacetate, and benzaldehyde) are formed by the decomposition of a hydroperoxide (tert-butyl α-hydroperoxyphenylacetate) and (or) by the recombination of peroxy radicals with and without chain termination. Benzaldehyde and tert-butyl α-hydroxyphenylacetate undergo radical chain oxidation in a reaction medium to result in benzoic acid and tert-butyl α-oxophenylacetate. Homolytic hydroperoxide decomposition is responsible for process autoacceleration and results in benzaldehyde, which is also formed from hydroperoxide by a nonradical mechanism, probably, via a dioxetane intermediate. Both of the reactions are catalyzed by benzoic acid. Benzoic acid has no effect on hydroperoxide conversion into tert-butyl α-oxophenylacetate, which most likely occurs as a result of hydroperoxide decomposition induced by peroxy radicals. The rate constants of the main steps of the process and kinetic parameters have been calculated by solving an inverse kinetic problem.     

Fock space perturbation theory

Diagonal and non-diagonal operators in Fock space are defined. With a universal Fock space wave operator W the Fock space hamiltonian H can be transformed to a diagonal operator L containing all relevant information about eigenvalues of H for arbitrary particle number in a simply coded form. W and L are constructed by perturbation theory, even in a spinfree form, and illustrated diagrammatically.     

Comparative study of azobenzene and stilbene bridged crown ether p-tert-butylcalix[4]arene

Photo-switchable calixarenes consisting of a stilbene or azobenzene bridge, spanning the narrow rim as a switching unit, were synthesized through reductive coupling of o-, m- and p-bis-benzaldehyde and bis-nitrobenzene-substituted calix[4]arenes. Both cis- and trans-stilbenes were produced from the reductive coupling of the o- and m-bis-benzaldehyde with the cis isomer being predominant for both regioisomers, whilst the coupling of p-bis-benzaldehyde gave only cis product. On the other hand, the only isolable product obtained from the reductive coupling of bis-o- and bis-m-nitrobenzene was the corresponding trans-azobenzene and the coupling product from bis-p-nitrobenzene was not stable. Each of the synthesized compounds showed a photostationary state in their cis-trans isomerization. The complexation of alkali metal ions was observed for only the o-azobenzene derivative suggesting that the lone pair of N-atom in the azo bridge participates in this process.     

An In Vitro Pilot Fermentation Study on the Impact of Chlorella pyrenoidosa on Gut Microbiome Composition and Metabolites in Healthy and Coeliac Subjects

The response of a coeliac and a healthy gut microbiota to the green algae Chlorella pyrenoidosa was evaluated using an in vitro continuous, pH controlled, gut model system, which simulated the human colon. The effect of C. pyrenoidosa on the microbial structure was determined by 16S rRNA gene sequencing and inferred metagenomics, whereas the metabolic activitywas determined by¹H-nuclear magnetic resonancespectroscopic analysis. The addition of C. pyrenoidosa significantly increased the abundance of the genera Prevotella, Ruminococcus and Faecalibacterium in the healthy donor, while an increase in Faecalibacterium, Bifidobacterium and Megasphaera and a decrease in Enterobacteriaceae were observed in the coeliac donor. C. pyrenoidosa also altered several microbial pathways including those involved in short-chain fatty acid (SCFA) production. At the metabolic level, a significant increase from baseline was seen in butyrate and propionate (p < 0.0001) in the healthy donor, especially in vessels 2 and 3. While acetate was significantly higher in the healthy donor at baseline in vessel 3 (p < 0.001) compared to the coeliac donor, this was markedly decreased after in vitro fermentation with C. pyrenoidosa. This is the first in vitro fermentation study of C. pyrenoidosa and human gut microbiota, however, further in vivo studies are needed to prove its efficacy.     

Solubilities of terephthalaldehydic,p-toluic,benzoic, terephthalic and isophthalic acids in N,N-dimethylformamide from 294.75 to 370.45 K

Using a laser monitoring observation technique, solubilities of terephthalaldehydic, p-toluic, benzoic, terephthalic and isophthalic acids in N,N-dimethylformamide have been measured as a function of temperature in the temperature range 294.75–370.45 K. The experimental data are correlated with the λh equation. The calculated results show good agreement with the experimental solubilities. The molar mixing enthalpy of solution H^E is estimated from the h parameter to discuss the properties of solution. In the terephthalic acid-N,N-dimethylformamide system a repulsive interaction exists between solute and solvent, which leads to an endothermic effect during dissolution. The strongest attractive interaction exists in the p-toluic acid-N,N-dimethylformamide system, causing a significant exothermic effect.     

Synthesis of enantiomeric pure lithium and potassium benzamidinate complexes

A new synthesis leading to the chiral amidines (S,S)- and (R,R)-N,N-bis-(1-phenylethyl)benzamidine ((S)- and (R)-HPEBA) in good yields is presented. Further reaction of (S)-HPEBA with n-BuLi gave the chiral lithium salt (S)-LiPEBA. Treatment of KH with (S)-HPEBA in boiling THF afforded the corresponding potassium salt (S)-KPEBA. In contrast by performing the reaction in boiling toluene a fast racemization was observed. In the solid state racemic KPEBA formed a dimer, in which all four nitrogen atoms are in a plane. To each potassium atom a toluene molecule is η⁶-coordinated.     

Identification of effective DNA barcodes for Triticum plants through chloroplast genome-wide analysis

The Egyptian flora is rich with a large number of Triticum plants, which are very difficult to discriminate between in the early developmental stages. This study assesses the significance of using two DNA Barcoding loci (matK and rbcL) in distinguishing between 18 different Triticum accessions in Egypt. We isolated and sequenced 15 rbcL and six matK fragments, but our analysis of the resultant sequences demonstrated a limited ability of matK and rbcL in distinguishing between Triticum accessions. Therefore, we pursued a bioinformatics approach to determine the most useful loci which may be used as DNA barcodes for the Triticum spp. We obtained the 10 available chloroplast genomes of the 10 Triticum species and sub-species from NCBI, and performed chloroplast genome-wide analysis to find the potential barcode loci. A total of 134 chloroplast genes, gene combinations, intergenic regions and intergenic region combinations were tested using a Tree-based method. We were unable to discriminate between Triticum species by using chloroplast genes, gene combinations and intergenic regions. However, a combination of the intergenic region (trnfM-trnT) with either (trnD-psbM), (petN-trnC), (matK-rps16) or (rbcL-psaI) demonstrated a very high discrimination capacity, suggesting their utilization as DNA barcodes for the Triticum plants. Furthermore, our novel DNA barcodes demonstrated high discrimination capacity for other Poaceae members.     

Stereoselective synthesis of both enantiomers of trans-2-(diphenylmethylideneamino)cyclopropanecarboxylic acid using a chiral pool approach and their incorporation in dipeptides

The stereoselective synthesis of (1R,2R)- and (1S,2S)-trans-2-(diphenylmethylideneamino)cyclopropanecarboxylic acid has been accomplished in six steps starting from (2S)- and (2R)-β-benzyl N-(tert-butoxycarbonyl)aspartate, respectively. The key-step in the reaction sequence is a stereoselective base-induced ring closure with a good trans diastereoselectivity. These novel trans-β-ACC derivatives could be incorporated in dipeptides employing a standard peptide coupling technique.     

Polymerization effects on molecular dynamics of n-ethylene glycol dimethacrylates followed by dielectric relaxation spectroscopy

A detailed dielectric characterization of n-ethylene glycol dimethacrylate monomers with n = 2 and 4 is provided. Besides the α relaxation associated to the glass transition, two secondary relaxation processes were detected: the γ process assigned to the twisting motions within the ethylene glycol moiety, and the β process related with hindered rotations of carboxylic groups. While the relaxation time of the γ process is independent of the size of the ethylene glycol group, the β process deviates to higher times with increasing n. Upon polymerization the α process goes to extinction, faster in the 4-ethylene monomer, with a concomitant depletion of the β process that remains at higher polymerization degrees relatively to the α process, thus acting as a more sensitive probe to evaluate conversion. The height decrease of α and β processes of monomers with the polymerization progress, occurs without significant changes of position. At intermediate states of polymerization, a new relaxation process evolves being only detectable in a narrow temperature range. In the end, the polymer networks show, in addition to the γ_pol relaxation identical to the γ relaxation of the monomer, a β_pol relaxation with similar features to the β relaxation found in poly n-alkyl methacrylates originated by a π flip of the ester unit accompanied by a restricted main chain rearrangement. The main dielectric relaxation corresponding to the swollen polymer network should appear at quite high temperatures already in early stages of the polymerization process because phase segregation occurs and only a limited amount of liquid monomer plasticizes the newly formed material.     

Yeasts and Lactic Acid Bacteria Mixed-Specie Biofilm Formation is a Promising Cell Immobilization Technology for Ethanol Fermentation

We previously found that some Saccharomyces cerevisiae and Lactobacillus plantarum remarkably formed mixed-specie biofilm in a static co-culture and deduced that this biofilm had potential as immobilized cells. We investigated the application of mixed-specie biofilm formed by S. cerevisiae BY4741 and L. plantarum HM23 for ethanol fermentation in repeated batch cultures. This mixed-specie biofilm was far abundantly formed and far resistant to washing compared with S. cerevisiae single biofilm. Adopting mixed-specie biofilm formed on cellulose beads as immobilized cells, we could produce enough ethanol from 10 or 20 % glucose during ten times repeated batch cultures for a duration of 10 days. Cell numbers of S. cerevisiae and L. plantarum during this period were stable. In mixed-specie biofilm system, though ethanol production was slightly lower compared to S. cerevisiae single-culture system due to by-production of lactate, pH was stably maintained under pH 4 without artificial control suggesting high resistance to contamination. Inoculated model contaminants, Escherichia coli and Bacillus subtilis, were excluded from the system in a short time. From the above results, it was indicated that the mixed-specie biofilm of S. cerevisiae and L. plantarum was a promising immobilized cell for ethanol fermentation for its ethanol productivity and robustness due to high resistance to contamination.     

Fine tuning of the structure of phosphine–phosphoramidites: application for rhodium-catalyzed asymmetric hydrogenations

Diastereomers of (4-(diphenylphosphino)pentan-2-yl)-N-isopropyl-{dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxa-phosphepin-2-yl}-4-amine, (S)-(2S,4S)-1, and (S)-(2R,4R)-3; the octahydro derivative 4 of (S)-(2S,4S)-1, and derivative 2 of (S)-(2S,4S)-1 containing a 1,3-propanediyl backbone, have been synthesized and used for rhodium-catalyzed asymmetric hydrogenations of prochiral olefins in order to study the role of the stereogenic elements in the backbone and in the terminal moiety. The central chirality in the bridge has been found to determine the configuration of the product with a cooperative effect from the terminal groups. Excellent ee’s (up to 99.9%) were obtained in the hydrogenation of methyl (Z)-α-acetamidocinnamate using a rhodium complex with the matched arrangement (S)-(2S,4S)-1. The hydrogenation is accomplished in a highly enantioselective manner by using green solvents such as propylene carbonate.     

Metamagnetism in DyBaCo2O5+x, x≈0.5

The temperature dependence of the paramagnetic susceptibility χ_m(T) taken in 2500 Oe, the resistivity ρ(T), and the thermoelectric power α(T) of DyBaCo₂O_5+x, which has Ba and Dy ordered into alternate (001) planes of an oxygen-deficient perovskite, have revealed a phase segregation in the compositional range 0.3?x<0.5. Orthorhombic DyBaCo₂O_5.51 has, in addition, oxygen vacancies ordered into alternate rows of the DyO_0.51 (001) planes; a cold-pressed polycrystalline sample exhibits a first-order insulator-metal transition at T_IM=320 K, a Curie temperature T_C=300 K, and a broadened metamagnetic transition temperature T_M≈265 K in 2500 Oe. A ferromagnetic M-H hysteresis curve fails to saturate at 5 T, and a minority ferromagnetic phase below T_M has a volume fraction that decreases with decreasing temperature, vanishing below 50 K. Oxygen vacancies in the DyBaCo₂O_5.5 phase suppress the metallic state; interstitial oxygen does not. A thermoelectric power α(T)>0 of DyBaCo₂O_5.51 changing continuously across T_IM is interpreted to manifest a metallic minority phase crossing a percolation threshold; α(T) also provides evidence for a progressive excitation of higher-spin Co(III) with increasing temperature from below 50 K to above T_IM. A previous model of the RBaCo₂O_5.5 phase is extended to account for the Ising spin configuration below T_C, the magnetic order in the presence of higher-spin octahedral-site Co(III), and the α(T) data.     

On the hyperfine structure and isotope shift of radium

The hyperfine structure and isotope shift of the heaviest known alkaline earth element radium (Z=88) have been studied in both the atomic Ra I and ionic Ra II spectra. The measurements, carried out by on-line collinear fast-beam laser spectroscopy, yield the hyperfine constantsA andB of the 7s and 7p _1/2 states in Ra II, of all states of the excited 7s 7p configuration and the 7s 7d ³ D ₃ state in Ra I. The data allow a consistent evaluation of the nuclear moments for eight odd-A radium isotopes. In particular, a complete analysis of the hyperfine structure of thesp configuration in the two-electron system provides a stringent test of the validity of the semi-empirical modified Breit-Wills theory. It is shown that the effective operator formalism is equivalent, if relativistic correction functions are used to reduce the number of parameters. The semi-empirical hyperfine fields are evaluated and found to agree generally with those from ab-initio calculations. The isotope shifts in thes?p,s ²?sp,sp?sd transitions are analysed semi-empirically and compared with ab-initio calculations. The consistency of the different analyses proves their validity and classifies the spectrum of Ra I as a model case for a simple and clean two-electron spectrum.     

Reactions of N- and C-alkenylanilines: IX. Synthesis, oxidation, and nitration of some 7-methyl-1,3a,4,8b-tetrahydrocyclopenta[b]indoles

Heating of 4-acyl-3-iodo-7-methyl-1,2,3,3a,4,8b-hexahydrocyclopenta[b]indoles in piperidine gave 4-acyl-7-methyl-1,3a,4,8b-tetrahydrocyclopenta[b]indoles which were oxidized with KMnO4 to obtain the corresponding 4-acyl-7-methyl-1,2,3,3a,4,8b-hexahydrocyclopenta[b]indole-1,2-diols. Oxidation of 4-acyl-7-methyl-1,3a,4,8b-tetrahydrocyclopenta[b]indoles at the olefinic double bond with hydrogen peroxide in acetonitrile in the presence of formic acid afforded stereoisomeric epoxides with cis and trans orientation of the nitrogen-containing and oxirane rings. Nitration with a mixture of ammonium nitrate and trifluoroacetic anhydride produced 5-nitro derivatives. The structure of 1-{(1aR*,1bR*,6bS*,7aS*)-5-methyl-1a,1b,2,6b,7,7ahexahydrooxireno[4,5]cyclopenta[1,2-b]indol-2-yl}ethanone was determined by X-ray analysis.