First total syntheses and configurational assignments of cytotoxic trichodenones A–C

Total syntheses of cytotoxic trichodenones A–C, produced by a strain of Trichoderma harzianum from the sponge Halichondria okadai, have been achieved, and the natural trichodenones B and C have been established to have (4R,1′R)- and (1′R)-configurations, respectively. From this synthesis and chiral HPLC analysis, it was deduced that the major molecule with R-configuration coexists with its enantiomer in natural trichodenone A.     

Hexamerin a Novel Protein Associated with Bacillus sphaericus Resistance in Culex quinquefasciatus

Bacterial insecticides like, Bacillus sphaericus and Bacillus thuringiensis serovar israelensis, have been used for the control of nuisance and vector mosquitoes for more than two decades. For many years, it was assumed that the use of microbial larvicides based on B. sphaericus would not lead to resistance in mosquitoes. However, recent reports have shown that B. sphaericus toxins are not free from this problem. Therefore, the resistance of mosquito populations to be will seriously threaten the sustainability of current mosquito control programme using these microbial insecticides. In the present study, we have characterised a novel protein responsible for resistance development in the filariasis vector of Culex quinquefasciatus. Laboratory selection experiments with B. sphaericus against the larvae were carried out up to 17 generations, and the occurrence of resistance was reported (resistance ratio (RR) at lethal concentration (LC)₅₀ and LC₉₀?=?1,987 and 2,051 folds, respectively). The protein profiles of B. sphaericus-resistant and susceptible population have confirmed with the expression of a new polypeptide (80 kDa) in the resistant strain only. Sequence result revealed that the newly expressed protein was ‘hexamerin’, and this factor might conceivably be responsible for the inheritance of resistance. This study is therefore valuable for comprehending the underlining factor and management of B. sphaericus resistance problem in mosquito population.     

Flavonoid Glycosides in Brassica Species Respond to UV-B Depending on Exposure Time and Adaptation Time

Recently, there have been efforts to use ultraviolet-B radiation (UV-B) as a biotechnological tool in greenhouses. Leafy Brassica species are mainly considered for their ability to synthesize glucosinolates and are valued as baby salads. They also have a remarkable concentration of chemically diverse flavonoid glycosides. In this study, the effect of short-term UV-B radiation at the end of the production cycle was investigated without affecting plant growth. The aim was to verify which exposure and adaptation time was suitable and needs to be further investigated to use UV as a biotechnological tool in greenhouse production of Brassica species. It is possible to modify the flavonoid glycoside profile of leafy Brassica species by increasing compounds that appear to have potentially high antioxidant activity. Exemplarily, the present experiment shows that kaempferol glycosides may be preferred over quercetin glycosides in response to UV-B in Brassica rapa ssp. chinensis, for example, whereas other species appear to prefer quercetin glycosides over kaempferol glycosides, such as Brassica oleracea var. sabellica or Brassica carinata. However, the response to short-term UV-B treatment is species-specific and conclusions on exposure and adaptation time cannot be unified but must be drawn separately for each species.     

The shape of micelles of a complex soap causing the Toms effect

It is well known that a small addition of some substances to a fluid is the cause of Toms effect. In order to explain this effect various theories have been proposed which take into consideration the shape of microparticles in the additives (macromolecules and soapmicelles). We have investigated the shape and the size of micelles or their aggregates of a complex soap consisting of two components: carboetoxypentadecyltrimethylammonium bromide andα-naphthol. The electron microscope was used for direct observations. The shape of micelles was estimated indirectly from rheometric measurements. The direct observation shows that there exists a great variety of shapes and sizes while rheology indicates that the micelles are fibrillous. The smallest observed micelles of the shape of sticks have dimensions of ca. 0.05×0.01μm and the smallest globules approximately 0.02μm.     

Novel porphyrin-quinazoline conjugates via the Diels-Alder reaction

Novel derivatives of meso-tetraphenylporphyrin with appended quinazoline moieties were synthesized, via the Diels-Alder reaction, between a 4-(porphyrinyl)pyrimidine ortho-quinodimethane and 1,4-benzoquinone, 1,4-naphthoquinone and N-(p-nitrophenyl)maleimide. The structure of one bis adduct was established by X-ray crystallography and mass spectrometry. We have unequivocally confirmed that the 2:1 adducts obtained from the reaction of pyrimidine-fused 3-sulfolenes with N-arylmaleimides have an open-chain structure and not a cyclooctapyrimidine structure, as previously published.     

Identification of the polymorphisms in IFITM3 gene and their association in a Korean population with ulcerative colitis

Interferons play critical roles in tumor pathogenesis by controlling apoptosis and through cellular anti-proliferative and differentiation activities. Interferon inducible transmembrane protein (IFITM) family genes have been implicated in several cellular processes such as the homotypic cell adhesion functions of IFN and cellular anti-proliferative activities. Expression levels of IFITM genes have been found to be up-regulated in gastric cancer cells and colorectal tumors. IFITM3 (also known as 1-8U) is a member of the IFITM family, and has been described as a key player in specification of germ cell fate. IFITM3 was first isolated from a genetic screen aimed at identifying genes involved in acquisition of germ cell competence. It has been proposed that epiblast cells have the highest expression of IFITM3 initiated germ cell specification and that homotypic association can discriminate germ cells from their somatic neighbors. In an attempt to better understand the genetic influences of IFITM3 on ulcerative colitis, we have identified possible variation sites and single nucleotide polymorphisms (SNPs) through two exons and their boundary IFITM3 intron sequences including the ~2.1 kb promoter regions. To determine whether or not these IFITM3 SNPs are associated with susceptibility to ulcerative colitis, frequencies of the genotype and allele of IFITM3 polymorphisms were analyzed on genomic DNAs isolated from patients with ulcerative colitis and from healthy controls. We also investigated the haplotype frequencies constructed by these SNPs in both groups. In this study, we also showed that expression level of IFITM3 mRNA was significantly higher in tissues of the ileum and cecum of the digestive system. We identified a total of seven SNPs and multiple variation regions in the IFITM3 gene. The genotype frequency of the g.-204T>G polymorphism in patients with ulcerative colitis was significantly different from that of the control group. Our results strongly suggest that polymorphisms of the IFITM3 gene may be associated with susceptibility to ulcerative colitis.     

In silico and in vivo study of adulticidal activity from Ayapana triplinervis essential oils nano-emulsion against Aedes aegypti

Nanoinsecticides of plant origin have advantages in the resistance of Aedes aegypti, vectors of infectious diseases. The objective of this study was to evaluate the insecticidal potential of Ayapana triplinervis essential oil nano-emulsions using in silico and in vivo assays in an Aedes aegypti model. Molecular docking showed that minority compounds present in the morphotype A essential oil have a more significant binding affinity to inhibit acetylcholinesterase and juvenile hormone receptors. Aedes aegypti adults were susceptible to A. triplinervis at 150 µg.mL-1 in a diagnostic time of 15 min for morphotype A essential oil nano-emulsion and 45 min for morphotype B essential oil nano-emulsion. The evaluation of toxicity in Swiss albino mice indicated that the nano-emulsions had low acute dermal toxicity and presented LD₅₀ greater than 2000 mg.Kg^?1. Thus, it is possible to conclude that nano-emulsions have the potential to be used in the chemical control of A. aegypti.     

Studies with inorganic precipitative membranes: XI. Membrane potential response,characterization and evaluation of effective fixed charge density

Membrane potentials arising across parchment supported nickel and cobalt phosphate membranes when they separete 1:1 electrolyte solutions of concentration c₁ and c₂ such that c₁=10 c₂, have been measured. The membranes in contactwith dilute solutions have been found to carry a negative charge whereas the charge reversal was observed when the membrane was separating concentrated solutions. The membrane potential data have been used according to the procedure prescribed by Teorell-Meyer-Sievers theory (the TMS theory) to derive the value of effective fixed charge density of membranes. The electrical double layer at the membrane-solution interface has been suggested to control the over all rate of diffusion.     

Preparation and properties of some citrullinep-nitroanilide derivatives for possible use as protease substrates

A number of citrullinep-nitroanilides have been synthesised as potential substrates for proteolytic enzymes. N ∝-Benzyloxycarbonyl-l-citrullinep-nitroanilide, a key starting material, was prepared by the phosphoazo method. During this reaction, depending on the conditions, lactam formation and decarbamoylation took place. It is probable that decarbamoylation took place subsequent to the lactamisation step. The derivatives prepared included some protected tripeptide nitroanilides, benzyloxycarbonylglycyl-l-prolyl-l-citrullinp-nitroanilide, bezyloxycarbonyl-d-phenylalanyl-lprolyl-l-citrullineP-nitroanilide, benzyloxycarbonylglycyl-l-phenylalanyl-l-citrullinep-nitroanilide, methyloxycarbonylglycyl-l-phenylalanyl-l-citrullinep-nitroanilide and a protected tetrapeptide, benzyloxycarbonylglycyl glycyl-l-phenylalanyl--l-citrullinep-nitroanilide.Prelimnary results have indicated that citrullinepnitroanilides are far more susceptible to hydrolysis by plant thiol enzymes such as papain, ficin and bromelain than by mammaalian serine proteases.     

Synthesis and antifungal activity of novel 1-(1H-benzoimidazol-1-yl)propan-2-one oxime-ethers containing the morpholine moiety

A series of 1-(2-(4-morpholinomethyl)-1H-benzoimidazol-1-yl)propan-2-one oxime-ethers have been synthesized from 2-chloromethyl-1H-benzoimidazole, morpholine, bromoacetone, hydroxylamine, and a haloalkane (or benzyl halide). Their structures were elucidated by IR, ¹H NMR, elemental analysis, and MS. Antifungal activity against Botrytis cinerea, Sclerotinia sclerotiorum, and Beans sclerotia was evaluated by the mycelium growth-rate method; the results indicated that many of the target compounds have excellent antifungal activity, even higher than that of the control fungicide (carbendazim).     

Rh-catalyzed π-facial selective intermolecular hydroacylation of norbornenes

Rh-catalyzed π-facial selective intermolecular hydroacylations of norbornenes with salicylaldehyde have been attained. In the reaction with norbornylene, the exo-hydroacylated product was produced because of steric hindrance. In the case of norbornadiene, the endo-product was obtained because of chelation effect. Lastly, because of chelation and remote substituent effects, the product formed in the reaction of 7-tert-butoxynorbornadiene was the endo,syn-product. Deuterium-labeling experiments revealed that the hydroacylation stereoselectively proceeded via endo- and exo-intermediates.     

Synthesis of Aliphatic Esters of Cinnamic Acid as Potential Lipophilic Antioxidants Catalyzed by Lipase B from Candida antarctica

Immobilized lipase from Candida antarctica (Novozyme 435) was tested for the synthesis of various phenolic acid esters (ethyl and n-butyl cinnamate, ethyl p-coumarate and n-butyl p-methoxycinnamate). The second-order kinetic model was used to mathematically describe the reaction kinetics and to compare present processes quantitatively. It was found that the model agreed well with the experimental data. Further, the effect of alcohol type on the esterification of cinnamic acid was investigated. The immobilized lipase showed more ability to catalyze the synthesis of butyl cinnamate. Therefore, the process was optimized for the synthesis of butyl cinnamate as a function of solvent polarity (logP) and amount of biocatalyst. The highest ester yield of 60.7 % was obtained for the highest enzyme concentration tested (3 % w/w), but the productivity was for 34 % lower than the corresponding value obtained for the enzyme concentration of 1 % (w/w). The synthesized esters were purified, identified, and screened for antioxidant activities. Both DPPH assay and cyclic voltammetry measurement have shown that cinnamic acid esters have better antioxidant properties than cinnamic acid itself.     

Dilute solutions of polyelectrolytes—IV. Unperturbed dimensions of N,N-diethylacrylamide-N,N-dimethyldiallylammonium chloride copolymers

The behaviour of copolymers of N,N-diethylacrylamide with N,N-dimethyldiallylammonium chloride in aqueous NaCl solution has been studied by light-scattering. The parameters characterizing the short- and long-range interactions have been calculated. The influence of copolymer composition on the gyration radius and unperturbed dimensions shows that the macromolecules have maximum flexibility for a composition near equimolar. This behaviour was attributed to decrease of both the electrostatic repulsions and the steric hindrance of the structural units, as a result of pronounced alternation.     

Dielectric relaxation and effect of plasticisers on siloxane polymers

Studies of dielectric relaxation of polydimethyl siloxane have shown that there is anomalous behaviour near its melting point (≈ ?50°), probably due to the presence of “Rotator Phases”. A detailed study of polyphenyl methyl siloxane, with various polar and non-polar diluents, has been carried out. The most interesting aspect of this study is the systematic broadening of the loss curves with increasing concentration of diluents while retaining conformity with the empirical decay function π(t) = exp ? (t/τ_o)^β. The broadening of loss curves was explained in terms of a distribution of local concentration of the diluents. The range of concentration (ΔC) was calculated for various diluents. It was found that ΔC was larger for the polar diluents than for the non-polar diluents. This result shows that polar plasticiser molecules have changed considerably the environment of the segmental motion of the basic polymer. There is also a linear relationship between the loss factor maximum (?^″_m) with the number of carbon atoms in the plasticiser molecule.     

Enthalpic interactions between some amino acids and cyclohexanone in aqueous solutions at 298.15 K

The enthalpies of mixing of glycine, l-α-alanine, l-γ-aminobutyric acid, l-α-valine, l-α-serine and l-α-threonine with cyclohexanone in aqueous solutions and their respective enthalpies of dilution have been measured by calorimetry at 298.15 K. Experimental enthalpies of dilution and mixing have been correlated with the virial expansion equation that was obtained with the McMillan-Mayer theory. The enthalpic interaction parameters h_xy, h_xxy and h_xyy of the amino acids studied with cyclohexanone in aqueous solutions have been evaluated, and the heterotactic enthalpic pair interaction coefficients (h_xy) are discussed in terms of solute-solute interactions.     

Antiproliferation and Induction of Apoptosis in Ca9-22 Oral Cancer Cells by Ethanolic Extract of <em>Gracilaria tenuistipitata</em>

The water extract of Gracilaria tenuistipitata have been found to be protective against oxidative stress-induced cellular DNA damage, but the biological function of the ethanolic extracts of G. tenuistipitata (EEGT) is still unknown. In this study, the effect of EEGT on oral squamous cell cancer (OSCC) Ca9-22 cell line was examined in terms of the cell proliferation and oxidative stress responses. The cell viability of EEGT-treated OSCC cells was significantly reduced in a dose-response manner (p < 0.0001). The annexin V intensity and pan-caspase activity of EEGT-treated OSCC cells were significantly increased in a dose-response manner (p < 0.05 to 0.0001). EEGT significantly increased the reactive oxygen species (ROS) level (p < 0.0001) and decreased the glutathione (GSH) level (p < 0.01) in a dose-response manner. The mitochondrial membrane potential (MMP) of EEGT-treated OSCC cells was significantly decreased in a dose-response manner (p < 0.005). In conclusion, we have demonstrated that EEGT induced the growth inhibition and apoptosis of OSCC cells, which was accompanied by ROS increase, GSH depletion, caspase activation, and mitochondrial depolarization. Therefore, EEGT may have potent antitumor effect against oral cancer cells.     

One-pot synthesis of meso-tris-aryl-substituted N-21-methyl- and N-21-benzyl-corroles

A simple and versatile synthesis of meso-substituted N-21-alkylcorroles was achieved directly from aldehydes, pyrrole and N-alkylpyrroles via mix-condensation. Compounds inaccessible via previous routes have been obtained in acceptable yields. It was proved that meso-substituted N-21-alkylcorroles differ from N-unsubstituted corroles in absorption spectra, stability and solubility.     

The critical phenomena of (water + AOT + decane) microemulsion with the molar ratio (ω = 30.0) of water to AOT

The coexistence curves of a ternary microemulsion system of {water + sodium di(2-ethylhexyl) sulfosuccinate (AOT) + n-decane} with the molar ratio (30.0) of water to AOT have been determined by measurements of refractive index at constant pressure within about 8 K from the critical temperature T_c. The critical exponent β and the critical amplitude B have been deduced from the coexistence curves. The experimental results have been analysed and compared with the system with molar ratio of 40.8 studied previously. It was found that the critical exponents β for both systems were consistent with the 3D-Ising value in a region sufficiently close to the critical temperature. The critical concentration was slightly affected by the molar ratio ω, but the critical temperature significantly was raised as the molar ratio ω was decreased. The volume fraction ϕ was the better choice of the concentration variable than the effective volume fraction ψ and the refractive index n used for constructing the order parameter for both systems.     

Antiviral-guided fractionation and isolation of phenolic compounds from Limonium densiflorum hydroalcoholic extract

A preliminary antiviral plate assay of the green solvent (hydro-ethanolic) shoot extract of Limonium densiflorum showed a potent activity against the herpes simplex virus type 1 (HSV-1). In order to isolate the active compounds, an in vitro bio-guided fractionation was undertaken by preparative chromatographic techniques. On the basis of nuclear magnetic resonance techniques, the structure of the isolated compounds was determined as gallic acid, epigallocatechin gallate, quercitrin, dihydrokaempferol, pinoresinol, N-trans-ferulolyl tyramine and (myricetin 3-O-α-rhamnopyranoside and myricetin 3-O-L-arabinofuranoside). Moreover, all isolated molecules were evaluated for their virucidality against HSV-1. Results showed that gallic acid and epigallocatechin gallate have strong activity, while pinoresinol and N-trans-ferulolyl tyramine have moderate activity. Whereas, the other molecules were inactive.