Quality Assessment of Bee Pollen-Honey Mixtures Using Thin-Layer Chromatography in Combination with Chemometrics

The aim of this study is to develop a rapid, effect-directed screening method for quality assessment of bee pollen-honey mixtures. The comparative antioxidant potential and phenolic content of honey, bee pollen, and the bee pollen-honey mixtures, was performed using spectrophotometry. The total phenolic content and antioxidative activity of bee pollen-honey mixtures with 20 % bee pollen share were in the range 3.03–3.11 mg GAE/g, and 6.02–6.96 mmol TE/kg, respectively, while mixtures with 30 % bee pollen share contained 3.92–4.18 mg GAE/g, and 9.69–10.11 mmol TE/kg. Chromatographic fingerprint of bee pollen-honey mixtures was performed by high-performance thin-layer chromatography with conditions developed by authors and reported for the first time. Fingerprint analysis hyphenated with chemometrics enabled authenticity assessments of honey in mixtures. Results indicate that bee pollen-honey mixtures represent a food with highly, both, nutritious characteristics and health-promoting effect.     

Novel Miscanthus hybrids: Modelling productivity on marginal land in Europe using dynamics of canopy development determined by light interception

New biomass crop hybrids for bioeconomic expansion require yield projections to determine their potential for strategic land use planning in the face of global challenges. Our biomass growth simulation incorporates radiation interception and conversion efficiency. Models often use leaf area to predict interception which is demanding to determine accurately, so instead we use low-cost rapid light interception measurements using a simple laboratory-made line ceptometer and relate the dynamics of canopy closure to thermal time, and to measurements of biomass. We apply the model to project the European biomass potentials of new market-ready hybrids for 2020–2030. Field measurements are easier to collect, the calibration is seasonally dynamic and reduces influence of weather variation between field sites. The model obtained is conservative, being calibrated by crops of varying establishment and varying maturity on less productive (marginal) land. This results in conservative projections of miscanthus hybrids for 2020–2030 based on 10% land use conversion of the least (productive) grassland and arable for farm diversification, which show a European potential of 80.7–89.7 Mt year⁻¹ biomass, with potential for 1.2–1.3 EJ year⁻¹ energy and 36.3–40.3 Mt year⁻¹ carbon capture, with seeded Miscanthus sacchariflorus × sinensis displaying highest yield potential. Simulated biomass projections must be viewed in light of the field measurements on less productive land with high soil water deficits. We are attempting to model the results from an ambitious and novel project combining new hybrids across Europe with agronomy which has not been perfected on less productive sites. Nevertheless, at the time of energy sourcing issues, seed-propagated miscanthus hybrids for the upscaled provision of bioenergy offer an alternative source of renewable energy. If European countries provide incentives for growers to invest, seeded hybrids can improve product availability and biomass yields over the current commercial miscanthus variety.     

Induction and axial patterning of the neural plate: Planar and vertical signals

In this review I summarize recent findings on the contributions of different cell groups to the formation of the basic plan of the nervous system of vertebrate embryos. Midline cells of the mesoderm—the organizer, notochord, and prechordal plate—and midline cells of the neural ectoderm—the notoplate and floor plate—appear to have a fundamental role in the induction and patterning of the neural plate. Vertical signals acting across tissue layers and planar signals acting through the neural epithelium have distinct roles and cooperate in induction and pattern formation. Whereas the prechordal plate and notochord have distinct vertical signaling properties, the initial anteroposterior (A-P) pattern of the neural plate may be induced by planar signals originating from the organizer region. Planar signals from the notoplate may also contribute to the mediolateral (M-L) patterning of the neural plate. These and other findings suggest a general view of neural induction and axial patterning. © 1993 John Wiley & Sons, Inc.     

The effect of deoxycholate on yeast cell permeability

1. (1)
   Мембраны ненарушенных клеток дрожжей непроницаемы для солей янтарной кислоты и феррицианида, так что в их суспензии не наблюдается сукцинодегидрогеназы с феррикианидом как акцептором электронов.     

Effect of small doses of X-rays on formation of colour variants bySerratia marcescens

1. (1)
   Клетки Serratia marcescens, которые выжили после повторных облучений лучами Х, при новй однокртном облучении процент цветных мутантов. Процент мутаций возрастает в зависимости от дозы облучения ночти линейно.     

Illegitimate integration of single-stranded DNA in Saccharomyces cerevisiae

We studied illegitimate recombination by transforming yeast with a single-stranded (ss) non-replicative plasmid. Plasmid pCW12, containing the ARG4gene, was used for transformation of yeast strains deleted for the ARG4, either in native (circular) form or after linearization within the vector sequence by the restriction enzyme ScaI. Both circular and linearized ss plasmids were shown to be much more efficient in illegitimate integration than their double-stranded (ds) counterparts and more than two-thirds of the transformants analysed contained multiple tandem integrations of the plasmid. Pulsed-field gel electrophoresis of genomic DNA revealed significant changes in the karyotype of some transformants. Plasmid DNA was frequently detected on more than one chromosome and on mitotically unstable, autonomously replicating elements. Our results show that the introduction of nonhomologous ss DNA into yeast cells can lead to different types of alterations in the yeast genome.     

Temperature and dissolved oxygen concentration as parameters of Azotobacter chroococcum cultivation for use in biofertilizers

Summary Azotobacter chroococcum was grown in continuous culture at two temperatures (30 °C and 20 °C) and different dissolved oxygen tensions (DOT) (30 % to 40 % and 70 % to 80 % of air saturation), respectively. At the temperature of 30 °C and low DOT a relatively high volumetric productivity and efficiency of nitrogen fixation were obtained. After lowering the temperature to 20 °C, an intensive formation of cysts was observed associated with a drastic decrease of the bacterial growth. Bacteria in the form of cysts kept their physiological activity for a long period of time depending on temperature and preparation.