Helicity of N,N′-diaryl-trans-1,2-diaminocyclohexane derivatives. Implications for molecular helicity manipulations

Derivatives of trans-1,2-diaminocyclohexane (DACH), useful as chiral ligands, scaffolds and building blocks, differ in their conformation. The conformation of N,N′-diaryl-DACH derivatives was studied by the semiempirical and DFT computational methods and by exciton-coupled circular dichroism. It was found that, contrary to M-helical N,N′-diimine, N,N′-diimide and N,N′-diamide derivatives, the aromatic residues in N,N′-diphenyl derivatives are oriented to form a P-helix for the (R,R)-DACH absolute configuration. The helicity of the bis-aryl system is modified in the case of 1-naphthyl or 2-naphthyl derivatives. Further switching of helicity has been demonstrated by either protonation or mono-N-acetylation of N,N′-diaryl DACH derivatives.     

Protective Effects of Cinnamaldehyde on the Inflammatory Response,Oxidative Stress,and Apoptosis in Liver of Salmonella typhimurium-Challenged Mice

Salmonella typhimurium infection is associated with gastrointestinal disorder and cellular injury in the liver of both humans and animals. Cinnamaldehyde, the main component of essential oil from cinnamon, has been reported to have anti-inflammatory, anti-oxidative, and anti-apoptotic effects. However, it remains unknown whether cinnamaldehyde can alleviate Salmonella typhimurium infection-induced liver injury in mice. In the present study, we found that cinnamaldehyde attenuated Salmonella typhimurium-induced body weight loss, the increase of organ (liver and spleen) indexes, hepatocyte apoptosis, and the mortality rate in mice. Further study showed that cinnamaldehyde significantly alleviated Salmonella typhimurium-induced liver injury as shown by activities of alanine transaminase, aspartate transaminase, and myeloperoxidase, as well as malondialdehyde. The increased mRNA level of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IFN-γ) and chemokines (CCL2 and CCL3) induced by Salmonella typhimurium were significantly abolished by cinnamaldehyde supplementation. These alterations were associated with a regulatory effect of cinnamaldehyde on TLR2, TLR4, and MyD88. 16S rDNA sequence analysis showed that Salmonella typhimurium infection led to upregulation of the abundances of genera Akkermansia, Bacteroides, Alistipes, Muribaculum, and Prevotellaceae UCG-001, and downregulation of the abundances of genera Lactobacillus, Enterorhabdus, and Eggerthellaceae (unclassified). These alterations were reversed by cinnamaldehyde supplementation. In conclusion, cinnamaldehyde attenuated the inflammatory response, oxidative stress, and apoptosis in the liver of Salmonella typhimurium-infected mice. Supplementation of cinnamaldehyde might be a preventive strategy to alleviate liver injury caused by Salmonella typhimurium infection in humans and animals.     

Cross-Kingdom Gene regulation via miRNAs of Hypericum perforatum (St. John’s wort) flower dietetically absorbed: An in silico approach to define potential biomarkers for prostate cancer

Prostate cancer (PCa) is the most frequent type of cancer in men. Hypericum perforatum (H. Perforatum) extract (HPE) administration provides remarkable decrease of PCa development. H. perforatum contains 7 conserved miRNAs (Hyp-miR-156a, Hyp-miR-156b, Hyp-miR-166, Hyp-miR-390, Hyp-miR-394, Hyp-miR-396 and Hyp-miR-414) with different targets. In this study, we aimed to investigate cross-kingdom gene regulation via miRNAs of H. perforatum flower dietetically absorbed in manner of an in silico approach to define potential biomarkers for PCa. psRNATarget database was used to find human genes targeted by 7 pre-defined H. perforatum miRNAs. We defined the mostly affected gene families from these miRNAs as ZNF, TMEM, SLC and FAM gene families. GeneMANIA database was used to define the most affected genes (TMEM41B and SLC4A7) from these 7 miRNAs. cBioPortal database was used to define alteration frequencies of TMEM41B and SLC4A7 on different types of PCa and to measure the mutual interaction potency and significance of co-occurence in PCa. This analysis showed that neuroendocrine prostate cancer (NEPC) had the highest total mutation frequency (22%) of TMEM41B and SLC4A7 genes. Also, TMEM41B and SLC4A7 genes had an average 2.1% pathway change potential among all different types of PCa. Moreover, TMEM41B and SLC4A7 gene pair was found significantly co-occurrent in PCa (p < 0.001). Finally, via GEPIA database, we used Spearman correlation analysis to measure the correlation degree of TMEM41B and SLC4A7 genes in PCa and found their significant correlation with PCa (p = 1.2 × 10⁻¹², R = 0.28). All in all, it was proved in silico and supported with previously known clinical data that SLC4A7 and TMEM41B potentially have a significant and critical tumor suppressive role for PCa, and show this effect combinatorily working together. This is the first study correlating SLC4A7 and TMEM41B with PCa significantly.     

Engineering of Yeast Old Yellow Enzyme OYE3 Enables Its Capability Discriminating of (E)-Citral and (Z)-Citral

The importance of yeast old yellow enzymes is increasingly recognized for direct asymmetric reduction of (E/Z)-citral to (R)-citronellal. As one of the most performing old yellow enzymes, the enzyme OYE3 from Saccharomyces cerevisiae S288C exhibited complementary enantioselectivity for the reduction of (E)-citral and (Z)-citral, resulting in lower e.e. value of (R)-citronellal in the reduction of (E/Z)-citral. To develop a novel approach for the direct synthesis of enantio-pure (R)-citronellal from the reduction of (E/Z)-citral, the enzyme OYE3 was firstly modified by semi-rational design to improve its (R)-enantioselectivity. The OYE3 variants W116A and S296F showed strict (R)-enantioselectivity in the reduction of (E)-citral, and significantly reversed the (S)-enantioselectivity in the reduction of (Z)-citral. Next, the double substitution of OYE3 led to the unique variant S296F/W116G, which exhibited strict (R)-enantioselectivity in the reduction of (E)-citral and (E/Z)-citral, but was not active on (Z)-citral. Relying on its capability discriminating (E)-citral and (Z)-citral, a new cascade reaction catalyzed by the OYE3 variant S296F/W116G and glucose dehydrogenase was developed, providing the enantio-pure (R)-citronellal and the retained (Z)-citral after complete reduction of (E)-citral.     

Evaluation of the Membrane Damage Mechanism of Chlorogenic Acid against Yersinia enterocolitica and Enterobacter sakazakii and Its Application in the Preservation of Raw Pork and Skim Milk

Plant-derived antimicrobial agents have adequate antimicrobial effects on food-borne pathogens, which can be used as food preservatives. The purpose of this study was to evaluate the antibacterial mechanism of chlorogenic acid (CA) against Yersinia enterocolitica and Enterobacter sakazakii. The minimum inhibitory concentration (MIC) of CA was determined by employing the broth microdilution method. Then, the cell function and morphological changes of Y. enterocolitica and E. sakazakii treated with CA were characterized. Finally, the growth inhibition models of Y. enterocolitica in raw pork and E. sakazakii in skim milk were constructed through the response surface methodology. The results demonstrated that CA has a satisfactory inhibitory effect against Y. enterocolitica and E. sakazakii with a MIC of 2.5 mg/mL. In addition, CA inhibited the growth of Y. enterocolitica and E. sakazakii via cell membrane damage, such as depolarization of the cell membrane, reduction in intracellular adenosine triphosphate (ATP) and pH levels, and destruction of cell morphology. Moreover, CA reduced two log cycles of Y. enterocolitica in raw pork and E. sakazakii in skim milk at a certain temperature. According to the corresponding findings, CA has the potential to be developed as an effective preservative to control Y. enterocolitica and E. sakazakii-associated foodborne diseases.     

Analysis and purification of O-decanoyl sucrose regio-isomers by reversed phase high pressure liquid chromatography with evaporative light scattering detection

Purification of seven regio-isomers of O-decanoyl sucrose, 2-O-, 3-O-, 4-O-, 6-O-, 3′-O-, 4′-O- and 6′-O-decanoyl sucrose, were performed by LC followed by preparative RP-HPLC with ELSD. Using an optimized gradient of acetonitrile in water 2-O-, 3-O-, 6-O- and 3′-O-decanoyl sucrose were purified in yields (w/w) of 52.5%, 34.7%, 45.0% and 36.9%, respectively. In the purified preparations of the 2-O- and 3′-O-decanoyl sucrose respectively, acyl migration was observed as a result of the drying process. Lyophilization resulted in the highest purities (w/w) of 96% and 100% for the 2-O- and the 3′-O-decanoyl sucrose, respectively.     

Hardness evaluation of cured urea–formaldehyde resins with different formaldehyde/urea mole ratios using nanoindentation method

To understand the influence of formaldehyde/urea (F/U) mole ratio on the properties of urea–formaldehyde (UF) resins, this study investigated hardness of cured UF resins with different F/U mole ratios using a nanoindentation method. The traditional Brinell hardness (H_B) method was also used for comparison. The H_B of cured UF resin films with different F/U mole ratios was determined after exposing the films to different post-curing temperatures. The nanoindentation method was employed for these films to measure Meyer hardness (H_M) and reduced modulus (E_r) which have been used to calculate the elastic modulus (E_s) of cured UF resins. As the F/U mole ratio decreased, the H_B decreased continuously, indicating a less rigid network structure in low F/U mole ratio UF resins. The higher the post-curing temperature, the greater the value of H_B. The H_M value also showed a similar trend as a function of F/U mole ratio. However, the E_r and E_s did not show a consistent trend as exhibited by H_M and H_B. Both H_M and E_r showed much greater variation in the coefficient of variation (COV) at lower F/U mole ratios 1.0 and 1.2, indicating a more heterogeneous composition of these resins. Linear relationships between H_M and E_r indicate that heterogeneity of the surface composition of samples contributes greatly to variations in the measured values. This variability is discussed in terms of crystal structures present in the cured UF resins of low F/U mole ratios.     

Enhanced Oxytetracycline Production by Streptomyces rimosus in Submerged Co-Cultures with Streptomyces noursei

In the present study, Streptomyces rimosus was confronted with Streptomyces noursei, Penicillium rubens, Aspergillus niger, Chaetomium globosum, or Mucor racemosus in two-species submerged co-cultures in shake flasks with the goal of evaluating the oxytetracycline production and morphological development. The co-culture of S. rimosus with S. noursei exhibited stimulation in oxytetracycline biosynthesis compared with the S. rimosus monoculture, whereas the presence of M. racemosus resulted in a delay in antibiotic production. Different strategies of initiating the “S. rimosus + S. noursei” co-cultures were tested. The improvement in terms of oxytetracycline titers was recorded in the cases where S. noursei was co-inoculated with S. rimosus in the form of spores. As the observed morphological changes were not unique to the co-culture involving S. noursei, there was no evidence that the improvement of oxytetracycline levels could be attributed mainly to morphology-related characteristics.     

Composition and Antimicrobial Activity of Ilex Leaves Water Extracts

Plants from the Ilex genus are known for properties such as antimicrobial and anti-inflammatory activity, can act as antiobesity agents and thus can be helpful in medicine. Some holly species, such as Ilex paraguariensis (widely known in the form of popular beverage: yerba mate), have been investigated, while others have been partially researched or remain unknown. Therefore, we performed qualitative and quantitative phytochemical analyses and screened antimicrobial properties of lesser-studied species (I. aquifolium L., I. aquifolium ‘Argentea Marginata’ and I. × meserveae ‘Blue Angel’). I. paraguariensis was used as a standard species for comparison purposes. Investigations were performed on water extracts due to their expected activity and composition. Antimicrobial research included evaluating minimal inhibitory, bactericidal (Staphylococcus aureus and Escherichia coli) and fungicidal concentration (Candida albicans, Alternaria alternata, Fusarium oxysporum, and Aspergillus niger) of extracts. The influence of the extracts on the production, eradication, and viability of bacterial biofilms was also analysed. It was established that Ilex paraguariensis possesses the richest profile of hydroxycinnamic acids derivatives in terms of component concentration and diversity. Ilex spp., especially I. × meserveae, contain a slightly higher amount of flavonoids and more different flavonoid derivatives than I. paraguariensis. However, the strongest antibacterial activity was shown by I. aquifolium L. and its cultivar ‘Argentea Marginata’ in terms of minimal inhibitory, bactericidal and fungicidal concentration, and biofilm assays. Extracts from both species significantly reduced the biofilm viability of S. aureus as well, which may be of use in the production of multicomponent lavaseptics, antiseptics, diuretics (supporting urinary tract infection therapy) and, due to their action on fungi, additives to growth media for specific fungi. The significant content of saponins enables Ilex extracts to be used as natural emulsifiers, for example, in cosmetics. Moreover, relatively high chlorogenic acid and rutin content may suggest use of Ilex spp. to treat obesity, digestive problems, in chemoprevention, and as preservatives in the food industry.     

Polyfluorinated arylnitrosamines

N-Methyl-, N-n-butyl-, N-t-butylperfluoroarylamines undergo nitrosation with nitrous acid to give the corresponding N-nitroso derivatives. Perfluoroaryl groups were selected from the benzene, indane, biphenyl, naphthalene and pyridine series. According to ¹H and ¹⁹F NMR spectra, N-nitroso-N-methyl derivatives of polyfluoroarenes consist of E and Z isomers with the former prevailing. The more bulky n-butyl group promotes an increase in the formation of Z isomers. Only Z isomers have been obtained from N-t-butyl derivatives of perfluorinated 4-toluidine and 4-aminopyridine. The structure of the Z isomer of N-nitroso-N-methylperfluoro-4-toluidine is confirmed by X-ray data.     

Profiling of Volatile Compounds and Associated Gene Expression in Two Anthurium Cultivars and Their F1 Hybrid Progenies

Anthurium is an important ornamental crop in the world market and its floral scent can enhance its ornamental value. To date, studies of the components and formation mechanism of the floral scent of Anthurium are relatively few. In this study, the scent profiles of two Anthurium varieties were measured by gas chromatograph-mass spectrometer (GC-MS). There were 32 volatile organic compounds (VOCs) identified in Anthurium ‘Mystral’, and the most abundant compound was eucalyptol (57.5%). Extremely small amounts of VOCs were detected in Anthurium ‘Alabama’. Compared with A. ‘Alabama’, most genes related to floral scent synthesis exhibited a higher expression in A. ‘Mystral’, including AaDXS, AaDXR, AaMDS, AaHDS, AaTPS, AaDAHPS, AaADT2, AaPAL1, and AaPAL2. In order to produce new varieties of Anthurium with fragrance, 454 progenies of two crossbred combinations of A. ‘Mystral’ and A. ‘Alabama’ were obtained. Four F1 generation plants with different floral scent intensities were selected for further study. The major components of floral scent in the progenies were similar to that of the parental A. ‘Mystral’ plant. The expression patterns of genes related to floral scent synthesis were consistent with the relative contents of different types of VOCs. This study revealed the profiles of volatile compounds and associated gene expression in two Anthurium cultivars and their F1 hybrids, which provided a basis for the floral scent inheritance of Anthurium andraeanum.     

A spectroscopic study on medium polarity in fluorous alcohol

The paper describes the polarities of three fluorous (F) aliphatic alcohols: perfluorinated tert-butanol (F-t-BuOH), n-butanol (F-n-BuOH), and n-heptanol (F-n-HepOH). For the purpose, we conducted absorption and fluorescence spectroscopies of coumarin 153 (C153) and 102 (C102) in three F and 13 non-fluorous (non-F) alcohols and determined their maximum energies: ν^a (absorption) and ν^f (fluorescence). We obtained linear relationships between the Stokes shifts of the dyes (i.e., (ν^a − ν^f)) and a medium polarity parameter for 13 non-F alcohols, f(x): f(x) = [(D_s − 1)/(2D_s + 1) − (n² − 1)/(2n² + 1)], where D_s and n were the dielectric constant and refractive index of a solvent, respectively. By comparing the Stokes shifts of the dyes in three F alcohols with those in 13 non-F alcohols (i.e., (ν^a − ν^f) vs. f(x) plot), the D_s values in F-t-BuOH, F-n-BuOH, and F-n-HepOH were evaluated to be 2.7-3.9, 4.3-5.1, and 4.0-5.2, respectively, while those in the relevant non-F alcohols were 12.5, 17.5, and 12.9, respectively. Thus, the present experiments demonstrated that the polarities of these F alcohols were much lower than those of the relevant non-F alcohols.     

Regioselectivity in the reductive ring-opening reaction of 1,2-O-benzylidene sugars

Regioselectivity in the ring-opening reaction of 1,2-O-benzylidene sugars was studied. In the reductive ring-opening reaction of 1,2-O-benzylidene derivatives, only a CO1 bond was cleaved in the case of manno-type, but both the CO1 and CO2 bonds were cleaved in the case of gluco-type.     

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.     

Enhanced Green Fluorescent Protein Expression in Pleurotus ostreatus for In Vivo Analysis of Fungal Laccase Promoters

The laccase family of Pleurotus ostreatus has been widely characterized, and studies of the genes coding for laccase isoenzymes in P. ostreatus have so far led to the identification of four different genes and the corresponding cDNAs, poxc, pox1, poxa1b and poxa3. Analyses of P. ostreatus laccase promoters poxc, pox1, poxa1b and poxa3 have allowed identification of several putative response elements, and sequences of metal-responsive elements involved in the formation of complexes with fungal proteins have been identified in poxc and poxa1b promoters. In this work, development of a system for in vivo analysis of P. ostreatus laccase promoter poxc by enhanced green fluorescent protein expression is performed, based on a poly ethylene glycol-mediated procedure for fungal transformation. A quantitative measurement of fluorescence expressed in P. ostreatus transformants is hereby reported for the first time for this fungus.     

Toll-like Receptors Gene Expression in the Gastrointestinal Tract of Salmonella Serovar Pullorum-Infected Broiler Chicken

Salmonella enterica serovar Pullorum causes substantial mortality in chicks as well as results in persistent infection and vertical transmission in layer birds. An effective innate immune response in the early stages of infection could reduce bacterial colonization and mortality in chicks and persistency of infection in later stages. Toll-like receptors (TLRs), important components of innate immune response, plays a pivotal role in early recognition of pathogen as well as in the initiation of robust and specific adaptive immune response. In the present study, we quantified the expression levels of chicken TLRs (1LA, 1LB, 2A, 2B, 3, 4, 5, 7, 15, and 21) mRNA by quantitative real-time PCR in the gastrointestinal (GI) tissues (duodenum, jejunum, ileum, and cecum) of 3-day-old broiler chicks after 24 h of oral infection with S. enterica serovar Pullorum. We found significant upregulation of TLRs (TLR2, TLR4, TLR21) mRNA expressions in GI tract tissues after S. Pullorum infection. The exceptions were for TLR3 and TLR15 with decrease in the expression levels in the jejunum after infection. TLR4 gene expression was significantly (P?<?0.05) upregulated in the duodenum and ileum of infected chicks. Gene expression for some of the TLRs (TLR1LA, ILB, 2B, and TLR5) remained unchanged after infection with S. Pullorum in all the GI tissues studied. Most substantial change in gene expression was found for TLR21, being significantly (P?<?0.05) upregulated in all the tissues investigated. The differential expression levels of TLRs shed light on tailored innate immune response induced by S. Pullorum during the early stages of infection in chicks.     

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.     

Study of the contact charge transfer behavior between cryptophanes (A and E) and fullerene by absorption, fluorescence and H NMR spectroscopy

A group of novel cage-like compounds cryptophanes A and E were synthesized from vanillin by a three-step method. The intermolecular interaction between cryptophanes (A and E) and fullerene (C₆₀) was investigated in detail by absorption, fluorescence and ¹H NMR spectroscopy. The absorption of C₆₀ at 410-650 nm decreased in the presence of cryptophanes A or E. The decrease in absorption intensity was proportional to the concentration of cryptophanes A or E. On the other hand, the fluorescence intensity of cryptophanes A or E decreased and the emission maxima were blue-shifted with the increase in C₆₀ concentration. These results suggest that contact charge transfer (CCT) complexes can be formed from C₆₀ with cryptophanes A or E. In addition, the electrochemical behavior of cryptophanes (A and E) and C₆₀ was studied by cyclic voltammetry. The redox currents of cryptophanes (A and E) decreased and the peak potentials were shifted on addition of C₆₀. The changes in the chemical shifts (Δδ) of aromatic protons of cryptophanes (A and E) in their NMR spectra further support that CCT complexes were formed with cryptophanes as the electron donors and C₆₀ as the electron acceptor.     

Synthesis of homologously pure bacteriochlorophyll-e and f analogues from BChls-c/d via transformation of the 7-methyl to formyl group and self-aggregation of synthetic zinc methyl bacteriopheophorbides-c/d/e/f in non-polar organic solvent

Homologously pure methyl bacteriopheophorbides-e and f (BPhes-e/f_M) were prepared from modification of naturally occurring bacteriochlorophylls-c and d (BChls-c/d), respectively, by transformation of the methyl to formyl group at the 7-position. The absolute configuration of the 1-hydroxyethyl group at the 3-position of (Zn-)BPhes-e/f_M was determined from comparison with structurally known BChl-c/d epimers. Visible spectra of synthetic (Zn-)BPhe-c/d/e/f_M showed that the 7¹-oxidation and the 8²/12¹/20-methylation affected Soret, Q_x and Q_y bands of both the monomeric (in a polar organic solvent) and oligomeric species (in a non-polar solvent).