Production and Stability of Protease from <Emphasis Type="Italic">Candida buinensis</Emphasis>

Cow raw milk from dairy cooperatives was examined for its microbial composition. Among the isolates identified, 17.6% were yeasts. The most frequent genus was Candida, although members belonging to the genera Brettanomyces, Dekkera, and Geotricum were also identified. Although qualitative and quantitative tests for extracellular proteolytic activity were positive for all the species isolated, Candida buinensis showed the highest response (23.5 U/mg); therefore, it was selected for subsequent investigation. The results of fermentations carried out at variable temperature, pH, and soybean flour concentration, according to a 2³ full factorial design, demonstrated that this yeast ensured the highest production of extracellular proteases (573 U/mL) when cultivated at 35 °C, pH 6.5, and using soybean flour concentrations in the range 0.1–0.5% (w/v). The cell-free supernatants showed the highest activity at 25 °C and pH 7.0, and satisfactory stability in the ranges 25–30 °C and pH 7–9. The first-order rate constants of protease inactivation in the cell-free supernatants were calculated at different temperatures from semi-log plots of the residual activity versus time and then used in Arrhenius and Eyring plots to estimate the main thermodynamic parameters of thermoinactivation (E* = 40.0 kJ/mol; ΔH* = 37.3 kJ/mol; ΔS* = −197.5 J/mol K; ΔG* = 101 kJ/mol).     

Essential oil polymorphism of wild growing Hungarian thyme (Thymus pannonicus) populations in the Carpathian Basin

The volatile oil compositions of Thymus pannonicus All. from nineteen different localities of Hungary were analyzed by GC/MS. The essential oil content of the Hungarian thyme samples varied between very low (0.14 mL/100 g DW) and fairly high (1.9 mL/100 g DW) values. Significant essential oil polymorphism was found: altogether twelve chemovarieties may have been determined, representing a way of adaptation to different habitat conditions. The main volatile compound of chemotype 1 was thymol (24.6-67.5%), while in the case of chemotype 2, thymol (36.5-63.7%) and p-cymene (11.5-27.3%) predominated. Thymol (28.4-63.7%), p-cymene (11.5-31.8%) and gamma-terpinene (9.7-20.9%) were identified as the chief monoterpenes of chemotype 3, while chemotype 4 contained thymol (36.5%), p-cymene (27.3%) and neral (11.2%). Chemotype 5 accumulated thymol (38.5%), p-cymene (20.6%), gamma-terpinene (12.0%) and beta-bisabolene (10.3%) as its main volatiles. The oil of chemotype 6 can be characterized by thymol (41.9%), p-cymene (20.2%), isoborneol (10.3%) and gamma-terpinene (9.9%), while that of chemotype 7 consisted of thymol (27.7%), linalyl acetate (18.8%), gamma-terpinene (18.6%) and alpha-cubebene (13.9%). In the oil of chemotype 8, p-cymene (45.0%), geraniol (13.6%) and linalyl acetate (9.9%) were found in higher percentages, while chemotype 9 mainly produced linalyl acetate (36.2%) and geranyl acetate (20.2%). Chemotype 10 accumulated germacrene-D (43.4) and beta-caryophyllene (15.0%), while the oil of chemotype 11 contained caryophyllene oxide (45.2%), alpha-cubebene (15.7%) and linalool (13.8%) in high proportions. Germacrene-D (29.7%), beta-caryophyllene (22.0%) and farnesol (10.4%) were identified as main essential oil compounds of chemotype 12. The last nine chemotypes were new for the literature, while the first seven contained thymol as their chief compound. The role of certain sesquiterpenes was found to be considerable.     

Can glandular hair density be a breeding marker for Origanum vulgare subsp. hirtum with high essential oil content?

Origanum vulgare subsp. hirtum (Link) Ietswaart is an essential oil rich plant traditionally used as oregano. Based on the interest of the essential oil producing sector, in 2000 we have started a breeding program of O. vulgare subsp. hirtum. Plant material for our breeding work consists of 6 progeny. Individual evaluation of the plant material was carried out in 2008-2009 with the primary aim of finding mother plants with appropriate morphological features, high essential oil content (> 7%) and with carvacrol as the main essential oil component. Among the survey of morphological characteristics special attention was given to glandular hair density in order to test the usability of it as a morphological marker for screening progeny for high essential oil content. The characteristics of the progeny can be described with high variability ensuring the possibility of a good selection base. Evaluating the morphology, essential oil content and constitution of the individuals, 20 plants were selected on the grounds of their high (7-8.6%) essential oil content, high ratio (70-93%) of carvacrol in the essential oil and typical morphological features of O. vulgare subsp. hirtum. From the results of glandular hair density it can be stated that the correlation between glandular hair density of the upper, middle and lower leaves either on vegetative or generative shoots and essential oil content was never strong enough (correlation coefficient < or = 0.5) to use it exclusively as a morphological marker for individual selection.     

Sensitive high-performance anion-exchange chromatographic determination of paeoniflorin and albiflorin by pulsed amperometric detection after solid-phase extraction

We developed a method to simultaneously determine paeoniflorin and albiflorin levels using high-performance anion-exchange liquid chromatography with pulsed amperometric detection (HPAEC-PAD). The main principle of our method includes solid-phase extraction step using Amberlite XAD-2 sorbent to remove sugars and to selectively determine glycosides by PAD. Under these conditions, the linear dynamic range was 0.01–100 μg/mL, and the albiflorin and paeoniflorin detection limits (S/N = 3) were 5 and 10 pg, respectively. The intra- and inter-day precisions (RSDs) were <5.07%, and the average recoveries from Paeoniae Radix and Si-ni-san ranged from 97.12 to 101.15%. Our method showed high selectivity, high sensitivity, and good repeatability for analyzing albiflorin and paeoniflorin in oriental medicinal preparation.     

Thermomorphic fluorous phosphines as organocatalysts for Michael addition reactions

The fluorous phosphines P[(CH₂)_mR_fn]₃ (R_fn = (CF₂)_n−1CF₃; m/n = 2/8, 3/8, 3/10) are efficient nucleophilic catalysts of Michael addition reactions. They can be easily recycled based upon their highly temperature-dependent solubilities (thermomorphism), with recovery by simple liquid/solid phase separation. The phosphonium salt formed by reaction of the nucleophilic phosphine with the α,β-unsaturated system appears to be a significant component of the catalyst rest state.     

Cellulose nanofibers from white and naturally colored cotton fibers

Suspensions of white and colored nanofibers were obtained by the acid hydrolysis of white and naturally colored cotton fibers. Possible differences among them in morphology and other characteristics were investigated. The original fibers were subjected to chemical analysis (cellulose, lignin and hemicellulose content), X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM). The nanofibers were analyzed with respect to yield, elemental composition (to assess the presence of sulfur), zeta potential, morphology (by scanning transmission electron microscopy (STEM)) and atomic force microscopy (AFM), crystallinity (XRD) and thermal stability by thermogravimetric analysis in air under dynamic and isothermal temperature conditions. Morphological study of several cotton nanofibers showed a length of 85–225 nm and diameter of 6–18 nm. The micrographs also indicated that there were no significant morphological differences among the nanostructures from different cotton fibers. The main differences found were the slightly higher yield, sulfonation effectiveness and thermal stability under dynamic temperature conditions of the white nanofiber. On the other hand, in isothermal conditions at 180 °C, the colored nanofibers showed a better thermal stability than the white.     

Short, asymmetric synthesis of epi-morphine ACNO analogues

A concise and efficient asymmetric synthesis of ACNO analogues of morphine is reported.     

Polynuclear vanadium complexes from thermal decomposition of [V3O(O2CPh)6(H2O)3]Cl

Solid-state decomposition of [V3O(O2CPh)6(H2O)3]Cl at 300 degrees C followed by alcoholysis of the product gives the new vanadium complexes [V6O6(PhCO2)6(CH3O)6(CH3OH)3] (1), [V6O6(PhCO2)6(C2H5O)6(C2H5OH)3] (2), [V6O6(PhCO2)6(C3H7O)6(C3H7OH)3] (3), [V6O6(PhCO2)6(C4H9O)6(C4H9OH)3] (4) and [V4O4(OCH3)6(O2CPh)2(HOCH3)2] (5). Complexes 2, 3 and 5 have been crystallographically characterised. DC magnetic susceptibility studies on complex shows antiferromagnetic coupling leading to a S = 0 spin ground state.