Isolation and characterization of a major allergen in kiwi fruit

 The isolation of an important allergen in kiwi fruit (Actinidia chinensis) by ion-exchange chromatography (IEC) and micropreparative SDS-PAGE followed by electroelution is reported. The purity of the allergen was analysed by SDS-PAGE and immunoblotting with sera from patients who have an allergy to kiwi. The allergen was shown to have a molecular weight of 43 kDa by SDS-PAGE/immunoblotting and an isoelectric point of approximately 6.9 as estimated by IEC. In accordance with World Health Organization nomenclature, this allergen is called Act c 2. By immunoblot inhibition it was shown that epitopes from different allergens in kiwi fruit are also located on Act c 2. N-terminal amino acid sequencing of 17 amino acid residues did not reveal homology with the major allergens in birch pollen (Bet v 1), apple (Mal d 1) or with other proteins of allergenic plant foods. In addition, the isoelectric point of a 67-kDa allergen in kiwi fruit was estimated to be 7.4 by IEC, but micropreparative isolation of this allergen failed because of its very low content in the fruit. Received: 14 April 1997     

State-of-the art comparability of corrected emission spectra. 1. Spectral correction with physical transfer standards and spectral fluorescence standards by expert laboratories

The development of fluorescence applications in the life and material sciences has proceeded largely without sufficient concern for the measurement uncertainties related to the characterization of fluorescence instruments. In this first part of a two-part series on the state-of-the-art comparability of corrected emission spectra, four National Metrology Institutes active in high-precision steady-state fluorometry performed a first comparison of fluorescence measurement capabilities by evaluating physical transfer standard (PTS)-based and reference material (RM)-based calibration methods. To identify achievable comparability and sources of error in instrument calibration, the emission spectra of three test dyes in the wavelength region from 300 to 770 nm were corrected and compared using both calibration methods. The results, obtained for typical spectrofluorometric (0°/90° transmitting) and colorimetric (45°/0° front-face) measurement geometries, demonstrated a comparability of corrected emission spectra within a relative standard uncertainty of 4.2% for PTS- and 2.4% for RM-based spectral correction when measurements and calibrations were performed under identical conditions. Moreover, the emission spectra of RMs F001 to F005, certified by BAM, Federal Institute for Materials Research and Testing, were confirmed. These RMs were subsequently used for the assessment of the comparability of RM-based corrected emission spectra of field laboratories using common commercial spectrofluorometers and routine measurement conditions in part 2 of this series (subsequent paper in this issue).     

Genotypic and climatic influences on the concentration and composition of flavonoids in kale (Brassica oleracea var. sabellica)

The aim of this study was to determine the composition and concentration of flavonoid aglycones in kale, the dependence on genotype and their interaction with decreasing temperature and global radiation. Eight kale cultivars, comprising hybrid and traditional, old cultivars, were grown in a field experiment and harvested four times at 4-week intervals. The traditional, old cultivars in particular contained high concentrations of flavonoids. In all of the investigated cultivars, kaempferol was the main flavonoid aglycone, followed by quercetin and isorhamnetin, which was quantified in six of the eight cultivars. Furthermore, in six of the eight cultivars, the total concentration of flavonoids remained unchanged with decreasing temperature and global radiation. The quercetin concentration increased in five of these six cultivars, whereas the kaempferol concentration decreased. Interestingly, the quercetin-to-kaempferol ratio increased in all of the investigated cultivars, despite the fact that the radiation level decreased, suggesting that the impact of the decline in temperature could be responsible for this effect.     

Modeling and physical analysis of an out-of-plane capacitive MEMS transducer with dynamically coupled electrodes

Microsystem Technologies - This paper presents a physics-based system-level compact model of a novel out-of-plane capacitive MEMS transducer for detection of mechanical forces, pressure variations...     

Plant-Origin Stabilizer as an Alternative of Natural Additive to Polymers Used in Packaging Materials

Over the past 25 years, cannabis plants have gained major popularity in the research community. This study aimed to evaluate the antioxidant capacity and stabilization efficiency of cannabidiol (CBD) extract in two different polymers: polylactide (PLA) and ethylene–norbornene copolymer (Topas) that are used in packaging materials more often. The research technology included weathering in a special chamber, surface free energy and color change measurements, surface morphology and Fourier-transform infrared spectroscopy (FTIR) analysis, thermogravimetry, and determination of the oxidation induction time or temperature (OIT) values, based on which the effectiveness of the cannabidiol extract could be estimated. Obtained results showed that the addition of CBD to polymer mixtures significantly increased their resistance to oxidation, and it can be used as a natural stabilizer for polymeric products. Moreover, samples with cannabidiol changed their coloration as a result of weathering. Therefore, this natural additive can also be considered as a colorimetric indicator of aging that informs about the changes in polymeric materials during their lifetime. On the other hand, surface properties of samples with cannabidiol content did not alter much compared to pure Topas and PLA.     

Session and intersession experience related to treatment outcome in bulimia nervosa.

Treatment in bulimia nervosa is challenging, with rates of successful treatments for only about 50% of all patients. This study aimed to identify predictors of outcome through secondary analysis of data from a randomized clinical trial that compared inpatient and day hospital treatment for bulimia. Process measures included assessments of patients' in-session experiences, therapeutic alliance, and therapy-related intersession experiences (ISE). ISE measures were better predictors of outcome than pretreatment variables (e.g., social adjustment) or global therapeutic alliance. Outcome at 3 month follow-up was strongly related to the ISE dimension Recreating Therapeutic Dialogue with Negative Emotions, indicating a heightened risk of failure. Prediction of outcome by these variables showed a sensitivity of 0.86 and a specificity of 0.78, and 83% of patients could be correctly classified. These results show that certain aspects of ISE may serve as early and reliable indicators of long term treatment failure, prompting alternate treatment approaches and opening new directions of research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preliminary studies on the effect of processing on the IgE reactivity of tomato products

Tomatoes and tomato products, obtained from a market, from companies or prepared in research laboratories, were tested in order to investigate how different processes could modulate the IgE reactivity of these products. The protein fraction of the samples was extracted by using a low‐temperature method in order to avoid degradation, and then separated on SDS PAGE to evaluate the protein profile. All the separated samples were blotted onto nitrocellulose membranes and then individually tested with pooled human sera that had been obtained from patients allergic to tomato, in order to evaluate the potential IgE binding of the protein bands. Heat treatments conventionally employed for the production of tomato‐based products were found to strongly degrade proteins thus dramatically reducing their IgE reactivity; characteristic protein profiles were found for specific processes such as hot and cold break. Ultra‐high‐pressure treatments were found to generally preserve the integrity of tomato proteins and this was reflected by the unaltered IgE reactivity observed. Copyright © 2007 Society of Chemical Industry     

Evaluation of the reliability of transport networks based on the stochastic flow of moving objects

In transport networks, human beings are moving objects whose moving direction is stochastic in emergency situations. Based on this idea, a new model—stochastic moving network (SMN) is proposed. It is different from binary-state networks and stochastic-flow networks. The flow of SMNs has multiple-saturated states, that correspond to different flow values in each arc. In this paper, we try to evaluate the system reliability, defined as the probability that the saturated flow of the network is not less than a given demand d. Based on this new model, we obtain the flow probability distribution of every arc by simulation. An algorithm based on the blocking cutset of the SMN is proposed to evaluate the network reliability. An example is used to show how to calculate the corresponding reliabilities for different given demands of the SMN. Simulation experiments of different size were made and the system reliability precision was calculated. The precision of simulation results also discussed.     

In situ hybridization of microcolonies using catalyzed reporter deposition with tetramethylbenzidine: a method for detecting low numbers of bacterial cells in drinking water

In this study, catalyzed reporter deposition in situ hybridization (CARD—ISH) with tetramethylbenzidine (TMB) was used for rapid detection of the food pathogens Salmonella typhimurium and Escherichia coli. The bacteria in a sample were concentrated by membrane filtration. The filter membranes with the cells thus removed were incubated on nutrient agar for 4–5 h to allow the formation of microcolonies. Instead of fluorescent tyramide, 3,3′,5,5′-tetramethylbenzidine (TMB), which yields a blue precipitate, was used for signal amplification after in situ hybridization. Microcolonies amplified with TMB produced blue signals, which were sufficiently intense to allow visual evaluation either using a stereomicroscope, or even with the naked eye. Therefore even low cell numbers of hygienically critical bacteria can be detected on the filter membrane without a protracted examination. This enables the detection of low cell numbers (<10 cfu) in a sample of 100 ml tap water within 9–10 h.     

Microscopy of the Drosophila facet eye: vademecum for standardized fixation, embedding, and sectioning

We describe here a standardized method for histological processing of the Drosophila compound eye. Primary fixation with 2.5% glutaraldehyde, obligatorily supplemented with 0.1% household detergent regularly yielded the best structural preservation, as compared with that of other, more complicated fixation protocols tested. Notably, it proved indispensable not only to cut off the fly's head to facilitate the penetration of the reagents but also to open the chitinous head capsule. For this, we locally pierced the cuticle between the eyes, leaving the head structurally almost intact, a prerequisite for precisely aligning the head for microtomy. We developed a two-step re-embedding procedure allowing for exact and reproducible orientation of the fly heads. Thus, highly comparable series of cross sections through a representative number of ommatidia were obtained. The feasibility of our embedding and sectioning approach is finally demonstrated by three-dimensional reconstructions of the middle segments of the R1, R7, and R8 photoreceptor cells. We present reconstructions from structurally modified ommatidia, as seen after RNAi-mediated depletion of the endosomal adaptor protein p14, and from normal ommatidia corresponding to the wildtype.