Purification and preliminary characterization of a frog-derived proteinaceous chemoattractant eliciting prey attack by checkered garter snakes (Thamnophis marcianus)

A potent proteinaceous chemoattractant, eliciting prey attack by checkered garter snakes (Thamnophis marcianus) was isolated from aqueous washes of the common frogRana temporaria and purified by preparative continuous-elution electrophoresis. The biological activity of the frog crude extract or of the purified chemoattractive protein, measured by a snake bioassay, was unaffected by freezing, lyophilization, or dialysis but was lost after proteolytic digestion. The purified chemoattractant is glycosylated, has an apparent molecular mass of 24 kDa, estimated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE), and a pI of 4.8. It gave one spot in two-dimensional electrophoresis. The bioassay showed that this protein is highly attractive to snakes. The lowest concentration yielding positive responses in the snake bioassay was approximately 25 µg/ml. These results suggest that a water-soluble Mr 24 kDa glycoprotein molecule produced by the common frog may be a vomeronasal stimulus used by checkered garter snakes for prey recognition.     

Larvicidal Effect of a Cell-Wall Fraction Isolated from Alder Decaying Leaves

Decaying alder leaves in water from Alpine Aedes breeding sites, particularly their toxicity to larval Culicidae, were investigated and characterized with comparative toxicological and chemical methods. Bioassays that used third-instar Aedes aegypti as a reference species indicated that the larvicidal effect of crude leaf litter varied with decaying age of the litter, while no toxicity was detected from leaching water of the mosquito breeding sites. Ten-month-old leaf litter was the most toxic. Comparison of the different soluble and insoluble fractions obtained after sequential extraction of decomposed litter allowed us to localize the toxicity factor to an insoluble cell-wall fraction. The toxicity seems to be linked to phenolic activity. It is higher than that found for tannic acid solutions used as a reference to mimic the larvicidal effects of the molecules naturally occurring in decaying litter. The pattern of establishing the larvicidal effect of alder leaf litter in water of Alpine Aedes breeding sites is discussed.     

Introduction of disulfide bonds into Bacillus subtilis neutral protease

The effects of engineered disulfide bonds on autodigestion andthermostability of Bacillus subtilis neutral protease (NP-sub)were studied using site-directed mutagenesis. After modellingstudies two locations that might be capable of forming disulfidebonds, both near previously determined autodigestion sites inNP-sub, were selected for the introduction of cysteines. Analysisof mutant enzymes showed that disulfide bonds were indeed formedin vivo, and that the mutant enzymes were fully active. Theintroduced disulfides did not alter the autodigestion patternof the NP-sub. All mutant NP-subs exhibited decreased thermostability,which, by using reducing agents, was shown to be caused by theintroduction of the cysteines and not by the formation of thedisulfides. Mutants containing one cysteine exhibited intermoleculardisulfide formation at elevated temperatures, which, however,was shown not to be the cause of the decreased thermostability.Combining the present data with literature data, it would seemthat the introduction of disulfide bridges is unsuitable forthe stabilization of proteases. Possible explanations for thisphenomenon are discussed.     

Spin coating of hydrophilic polymeric films for enhanced centrifugal flow control by serial siphoning

In this paper, we implement rotational flow control on a polymeric microfluidic “lab-on-a-disc” platform by combining serial siphoning and capillary valving for sequential release of a set of on-board stored liquid reagents into a common (assay) channel. The functionality of this integrated, multi-step, multi-reagent centrifugal assay platform critically depends on the capability to establish very reproducible, capillary-driven priming of the innately only weakly hydrophilic siphon microchannels made from common poly(methyl methacrylate) (PMMA) substrates. Due to the relatively high contact angle of the native PMMA substrate, it was practically impossible to ensure sequential release of on-board stored reagents using the capillary-driven serial siphon valves. In this work, we demonstrate that spin-coated hydrophilic films of poly(vinyl alcohol) (PVA) and (hydroxypropyl)methyl cellulose (HPMC) provide stable contact angles on PMMA substrates for more than 60 days. The deposited films were characterized using contact angle measurements, surface energy calculations and X-ray photoelectron spectroscopy spectra. The PVA and HPMC films reduced the water contact angle of the PMMA substrate from 68° to 22° and 27° while increasing their surface energies from 47 to 62 and 57 mN m^?1, respectively. On the centrifugal microfluidic platform, the films were validated to enable the effective and reproducible priming of the serial siphon microchannels at low rotational frequencies while ensuring that the in-line capillary valves are not opened until their respective burst frequencies are passed. Furthermore, the biocompatibility of the proposed surface modification method was examined, and the platform was used to run a sandwich immunoassay for the detection of human immunoglobulin G, and its performance was proven to be comparable to dynamic coating using surfactants.     

Supercritical carbon dioxide extraction ofDimorphotheca pluvialis oil seeds

The possibility of extraction ofDimorphotheca oil with supercritical carbon dioxide is demonstrated in this article. Before extraction, the seeds have to be pretreated to improve extraction yield. Experiments showed that the best pretreatment procedure forDimorphotheca was heating the seeds under reduced pressure to 100°C for 60 min, followed by flaking or milling. To give an impression about the efficiency of the supercritical extraction, a mathematical model has been developed to estimate the overall mass transfer coefficient (A _p K). Also, an empirical relation betweenA _p K and the interstitial velocity has been found. The physical properties of the supercriticalDimorphotheca oil are in good agreement with those of conventionally extracted oil, except for a lower phospholipid content. It is expected that further refining of supercriticalDimorphotheca oil will be marginal.     

Taxonomic data integration from multilingual Wikipedia editions

Information systems are increasingly making use of taxonomic knowledge about words and entities. A taxonomic knowledge base may reveal that the Lago di Garda is a lake and that lakes as well as ponds, reservoirs, and marshes are all bodies of water. As the number of available taxonomic knowledge sources grows, there is a need for techniques to integrate such data into combined, unified taxonomies. In particular, the Wikipedia encyclopedia has been used by a number of projects, but its multilingual nature has largely been neglected. This paper investigates how entities from all editions of Wikipedia as well as WordNet can be integrated into a single coherent taxonomic class hierarchy. We rely on linking heuristics to discover potential taxonomic relationships, graph partitioning to form consistent equivalence classes of entities, and a Markov chain-based ranking approach to construct the final taxonomy. This results in MENTA (Multilingual Entity Taxonomy), a resource that describes 5.4 million entities and is one of the largest multilingual lexical knowledge bases currently available.     

Sorption characteristics of polycyclic aromatic hydrocarbons in aluminum smelter residues

High temperature carbon oxidation in primary aluminum smelters results in the release of polycyclic aromatic hydrocarbons (PAH) into the environment. The main source of PAH are the anodes, which are composed of petroleum coke (black carbon, BC) and coal tar pitch. To elucidate the dominant carbonaceous phase controlling the environmental fate of PAH in aluminum smelter residues (coke BC and/or coal tar), the sorptive behavior of PAHs has been determined, using passive samplers and infinitesink desorption methods. Samples directly from the wet scrubber were studied as well as ones from an adjacent 20-year old storage lagoon and roof dust from the smelter. Carbon-normalized distribution coefficients of native PAHs were 2 orders of magnitude higher than expected based on amorphous organic carbon (AOC)/water partitioning, which is in the same order of magnitude as reported literature values for soots and charcoals. Sorption isotherms of laboratory-spiked deuterated phenanthrene showed strong (-100 times stronger than AOC) but nonetheless linear sorption in both fresh and aged aluminum smelter residues. The absence of nonlinear behavior typical for adsorption to BC indicates that PAH sorption in aluminum smelter residues is dominated by absorption into the semi-solid coal tar pitch matrix. Desorption experiments using Tenax showed that fresh smelter residues had a relatively large rapidly desorbing fraction of PAH (35-50%), whereas this fraction was strongly reduced (11-16%) in the lagoon and roof dust material. Weathering of the coal tar residue and/or redistribution of PAH between coal tar and BC phases could explain the reduced availability in aged samples.     

Quasi-flat-top frequency-doubled Nd:glass laser for pumping of high-power Ti:sapphire amplifiers at a 0.1 Hz repetition rate

A Nd:glass laser based on a novel design delivers up to 120 J energy pulses with a quasi-flat-top spatial profile at a 0.1 Hz repetition rate. The laser output is frequency-doubled with 50% efficiency and used to pump Ti:sapphire amplifiers. The developed design is perspective for use in the currently contemplated next step in ultra-high-intensity laser development.     

Multivariate analysis of attenuated total reflection-Fourier transform infrared spectroscopic data to confirm the origin of honeys

Fourier transform infrared (FT-IR) spectroscopy and chemometrics were used to verify the origin of honey samples (n=150) from Europe and South America. Authentic honey samples were collected from five sources, namely unfiltered samples from Mexico in 2004, commercially filtered samples from Ireland and Argentina in 2004, commercially filtered samples from the Czech Republic in 2005 and 2006, and commercially filtered samples from Hungary in 2006. Samples were diluted with distilled water to a standard solids content (70 degrees Brix) and their spectra (2500-12 500 nm) recorded at room temperature using an FT-IR spectrometer equipped with a germanium attenuated total reflection (ATR) accessory. First- and second-derivative and standard normal variate (SNV) data pretreatments were applied to the recorded spectra, which were analyzed using partial least squares (PLS) regression analysis, factorial discriminant analysis (FDA), and soft independent modeling of class analogy (SIMCA). In general, when an attenuated wavelength range (6800-11 500 nm) rather than the whole spectrum (2500-12 500 nm) was studied, higher correct classification rates were achieved. An overall correct classification of 93.3% was obtained for honeys by PLS discriminant analysis, while FDA techniques correctly classified 94.7% of honey samples. Correct classifications of up to 100% were achieved using SIMCA, but models describing some classes had very high false positive rates.     

Social networks and partner stress as predictors of adherence to medication, rehabilitation attendance, and quality of life following acute coronary syndrome.

Objective: This study examined whether social network size and partner stress predicted medication adherence, cardiac rehabilitation attendance, and quality of life 12 months following hospitalization for an acute coronary syndrome (ACS). Design: ACS patients (N = 193, M age = 60.6 years, SD = 11.4 years, 23% female) were recruited shortly following admission to 4 local hospitals. A prospective design was employed with follow-up data collected 12 months following hospital admission. Main Outcome Measures: Data were gathered on social network size and partner stress. The main outcomes assessed at 12 months were medication adherence, cardiac rehabilitation attendance, and quality of life (Short Form 36). Results: Partner stress predicted medication nonadherence, odds ratio: 2.89, (95% CI = 1.21, 6.95). ACS patients with large social networks were more likely to attend rehabilitation, odds ratio: 3.42, (95% CI = 1.42, 8.25). Analyses were adjusted for age, gender, clinical risk scores, readmission/recurrence, and negative affectivity. Both partner stress and smaller social network size were associated with poorer quality of life. Conclusion: Social network size and partner stress may partly exert their influence on coronary heart disease morbidity and mortality through recovery behaviors and maintenance of quality of life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)