NeuN immunoreactivity in the brain of Xenopus laevis

Neuronal nuclear antigen (NeuN), discovered in mice brain cell nuclei by Mullen et al. (1992), is used as an excellent marker of post-mitotic neurons in vertebrates. In this study, the expression pattern of NeuN was examined in the Xenopus brain to explore phylogenetic differences in NeuN expression. Anti-NeuN antibody showed selective staining in mouse and Xenopus brain extracts, but the number and molecular weight of the bands differed in Western blotting analysis. In immunostaining, anti-NeuN antibody showed selective staining of neurons, but not glial cells, in the Xenopus brain. Most neurons, including olfactory bulb mitral cells and cerebellar Purkinjie cells, which show no immunoreactivity in birds/mammals, showed NeuN immunoreactivity in Xenopus. This study revealed that anti-NeuN antibody is a useful marker of post-mitotic neurons in amphibians, but it also stains neurons that show no reactivity in more derived animals.     

Artificial dispersal of the lichen Crocodia aurata (Lobariaceae) using asexual propagules and gel‐filled gauze packets

Lichens are an essential component of ecosystem processes. Many lichen species are habitat specialists that rely on specific tree substrates and moisture regimes of old‐growth forests and are not found in early‐successional forests, small isolated forest fragments or restoration projects, making them useful bioindicators of forest health. Pressures from habitat loss and fragmentation have affected the viability and survival of lichen species that are often limited by low dispersal ability. As a rule, lichens are rarely included in ecological restoration programmes despite translocation methods being available. We trialled a combination of two of the more successful methods (gauze packets and use of adhesive gels). Three different gelling agents were used in attempt to immobilize living soredia of the lichen Crocodia aurata on trunks of Ti Kouka/Cabbage Tree (Cordyline australis) for long enough for them to develop into thallus lobes. The effectiveness of these methods was tracked over a 2‐year period. Our results show that all three gel treatments were effective at immobilizing soredia in the gauze packets. Lobe formation occurred in all three gel treatments after 36 weeks, with methyl cellulose the most successful with six packets producing lobes, five Ac‐Di‐Sol^® and two agarose packets also producing lobes, out of a possible total 100 gauze packets. Lobe formation was slightly more successful on the south sides of trees (seven of thirteen packets), despite initial survival and vitality of soredia being higher on the north sides of the trees.     

Kinetic modelling of the production of methyl oleate by Celite® supported lipase sol–gels

This study illustrates the benefits of Celite^® supported lipase sol–gels for the transesterification of triolein to produce methyl oleate. A ping–pong bi–bi kinetic model was developed and validated taking into account the inhibition effects of methanol and glycerol as well as the effect of temperature. Although initial reaction rate models are useful for predicting the kinetics in the absence of products, a kinetic model beyond the initial conditions that considers glycerol inhibition is important. The model developed was consistent with the experimental data (R² = 0.95) predicting an increase in methyl oleate production with increasing methanol concentration up to an optimal range of 1.3 M to 2.0 M depending on the temperature. In general, increasing the temperature increased the initial reaction rate for the immobilized lipase over the temperature range of 40–60 °C. Based on the kinetic constants, the maximum velocity of the reverse reaction is about 25% slower than that of the forward reaction and glycerol inhibition has a more significant effect on the reaction kinetics than methanol inhibition. The model developed would be useful for understanding the effects of methanol and glycerol inhibition as well as temperature on the production of methyl oleate using lipase-mediated enzymatic transesterification.     

Environmental Effect of Sol-Gel Encapsulation on Photochromic andThermocliromic Anils

Photochromic and thermochromicanus have been encapsulated in an organic-inorganichybrid network, produced by theSol-Gel method. It was found that the photochromic anils have been transformed to thermochromic, something observed for the first time in rigid glasses. Spectroscopic investigations indicate a common infrastructure responsible for the coloured xerogel.     

Kinetic study of the colloidal and enzymatic stability of β-galactosidase,for designing its encapsulation route through sol–gel route assisted by Triton X-100 surfactant

The kinetic study of the colloidal and enzymatic stability for the β-galactosidase of Bacillus circulans was carried out in function of the presence of Triton X-100 surfactant, under orbital agitation and varying the pH and temperature. The correlation between the Dynamic Light Scattering and enzyme assay data, supported by z-potential and Differential Scanning Calorimetry analyses, gave insights about the mechanism of the protective role of the surfactant against the enzyme deactivation during its incubation. The best conditions for preserving the enzymatic activity, under orbital agitation, were: presence of 1 × 10⁻³M Triton X-100, at pH 6.0 and 25 °C or 40 °C during less than 24 h, even in the presence of 0.1 M sodium cations or 4% ethanol. As these conditions also affect the polycondensation of the siliceous species and the enzyme-silica interactions, these could be considered as primary information for designing and optimizing an encapsulation route of β-galactosidase in silica, by a sol–gel process assisted by surfactant.     

Pharmacological properties of dibenzo[a,c]cyclooctene derivatives isolated from Fructus Schizandrae chinensis I. Interaction with rat liver cytochrome P-450 and inhibition of xenobiotic metabolism and mutagenicity

Seven compounds isolated from Fructus Schizandrae chinensis, a traditional Chinese tonic, which is also able to decrease liver lesions by hepatoxic chemicals, are named Schizandrin (Sin) A, B and C, Schizandrol (Sol) A and B and Schizandrer (Ser) A and B. They are dibenzo[a,c]cyclooctene derivatives. Dimethyl-4,4′-dimethoxy-5,6,5′,6′-dimethylenedioxy-biphenyl-2,2′-dicarboxylate (DDB) is an intermediate for synthesizing Sin C. The interactions of these compounds with rat liver microsomes in vitro have been investigated. Sol A and Sol B gave type I difference spectrum, the other six compounds gave ‘reverse type I’ difference spectrum. When Schizandrins or DDB were incubated with NADPH-reduced microsomes, Sin B, Sin C, Sol B, Ser A and Ser B generated dual Soret peaks at 455–460 nm and 425–430 nm, the other three compounds caused a difference spectrum without 455 nm peak. All these compounds more or less inhibit liver microsomal hydroxylation of benzo[a]pyrene (BP) demethylation of aminopyrine. Sin B, Sol B and DDB decreased mutagenicity of BP in Ames test.