Universities of Applied Sciences.

When the SARS-CoV-2 pandemic started,[1] science came to the immediate attention of the broad public. People and politicians were hanging on every word of medical doctors, virologists, molecular biologists, data scientists and many others in the hope of finding other protective measures than those used for centuries such as basic hygiene, distance, or quarantine. Here, at the Institute of Chemistry and Biotechnology at the Zurich University of Applied Sciences (ZHAW) we were also willing to provide scientific solutions to overcome the pandemic. Together with our partners from industry, we contributed to the development of a Swiss vaccine, are working on filters for active ventilated full protective suits and are developing tests to show the efficacy and safety of an active antiviral textile that allows controlled virus inactivation through an electrochemical reaction by applying a small current.

Assessing High Performers in the Life Sciences: Characteristics of Exams Used at the International Biology Olympiad (IBO) and Their Implications for Life Science Education.

For decades, studies have revealed students' decreasing interest in science. Extracurricular learning opportunities-the Science Olympiads being a publicly well-known example-are an important means identified to tackle this challenge and help students further differentiate their interests. Better understanding the underlying constructs and characteristics of Science Olympiad exams can provide several implications not just for Science Olympiads, but also science education more broadly, for example, with regard to how the competitions' international juries defines expectations for high performance in the life sciences. This study analyzes exams set by the International Biology Olympiad (IBO) as an example for a top-tier international competition in the life sciences. The findings extend previous works on test item characteristics toward student competitions and high-performer education. We conducted a systematic analysis of N = 703 closed-ended and laboratory test items from six IBO assessment years across the competition's history. A categorical framework was developed to analyze items according to four areas: formal characteristics, content and practices, cognitive aspects, and the use of representations. Our findings highlight assessment characteristics used to challenge high-performing students. We derive implications for general life sciences education, as well as for further developing the assessments of Science Olympiads.

Unravelling the potential of seaweeds from the Black Sea coast of Romania as bioactive compounds sources. Part I: Cystoseira barbata (Stackhouse) C. Agardh.

The Romanian coastlines of the Black Sea have abundant seaweed resources, but little effort has been done to investigate their biological potential. The aim of the present study was to assess the in vitro antioxidant and anti-proliferative effects of Cystoseira barbata (Stackhouse) C. Agardh (Sargassaceae), a brown alga inhabiting the Black Sea coast of Romania. The 70% acetone, methanol and water extracts of C. barbata were evaluated for their total phenolic content, antioxidant activity and anti-proliferative potential against human tumor cell lines (pulmonary A549, colon HT-29, mammary MCF-7) and the non-tumor mammary epithelial MCF-10A cell line. C. barbata 70% acetone extract (CBAE) displayed the highest antioxidant and cytotoxic activities. The mechanism of CBAE anti-proliferative activity involved initially increased intracellular ROS accumulation, followed by increased DNA content in the subG1 phase and DNA fragmentation leading to excessive apoptosis. Thus, our study provides a theoretical basis for the use of CBAE as a tumor preventive agent. Furthermore, UHPLC-DAD-QTOF-MS analysis of CBAE tentatively identified 18 phlorotannins as fucophlorethol and eckol derivatives, containing three up to seven phloroglucinol units. In conclusion, C. barbata represents a valuable source for the development of macroalgal-based products with putative use as nutraceuticals and pharmaceuticals.

Is comfrey root more than toxic pyrrolizidine alkaloids? Salvianolic acids among antioxidant polyphenols in comfrey (Symphytum officinale L.) roots.

Comfrey root preparations are used for the external treatment of joint distortions and myalgia, due to its analgesic and anti-inflammatory properties. Up to date, key activity-determining constituents of comfrey root extracts have not been completely elucidated. Therefore, we applied different approaches to further characterize a comfrey root extract (65% ethanol). The phenolic profile of comfrey root sample was characterized by HPLC-DAD-QTOF-MS/MS. Rosmarinic acid was identified as main phenolic constituent (7.55 mg/g extract). Moreover, trimers and tetramers of caffeic acid (isomers of salvianolic acid A, B and C) were identified and quantified for the first time in comfrey root. In addition, pyrrolizidine alkaloids were evaluated by HPLC-QQQ-MS/MS and acetylintermedine, acetyllycopsamine and their N-oxides were determined as major pyrrolizidine alkaloids in the comfrey root sample. Lastly, the antioxidant activity was determined using four assays: DPPH and ABTS radicals scavenging assays, reducing power assay and 15-lipoxygenase inhibition assay. Comfrey root extract exhibited significant antioxidant activities when compared to known antioxidants. Thus, comfrey root is an important source of phenolic compounds endowed with antioxidant activity which may contribute to the overall bioactivity of Symphytum preparations.

Time-Resolved Gravimetric Method To Assess Degassing of Roasted Coffee.

During the roasting of coffee, thermally driven chemical reactions lead to the formation of gases, of which a large fraction is carbon dioxide (CO2). Part of these gases is released during roasting while part is retained inside the porous structure of the roasted beans and is steadily released during storage or more abruptly during grinding and extraction. The release of CO2 during the various phases from roasting to consumption is linked to many important properties and characteristics of coffee. It is an indicator for freshness, plays an important role in shelf life and in packaging, impacts the extraction process, is involved in crema formation, and may affect the sensory profile in the cup. Indeed, and in view of the multiple roles it plays, CO2 is a much underappreciated and little examined molecule in coffee. Here, we introduce an accurate, quantitative, and time-resolved method to measure the release kinetics of gases from whole beans and ground coffee using a gravimetric approach. Samples were placed in a container with a fitted capillary to allow gases to escape. The time-resolved release of gases was measured via the weight loss of the container filled with coffee. Long-term stability was achieved using a customized design of a semimicro balance, including periodic and automatic zero value measurements and calibration procedures. The novel gravimetric methodology was applied to a range of coffee samples: (i) whole Arabica beans and (ii) ground Arabica and Robusta, roasted to different roast degrees and at different speeds (roast air temperatures). Modeling the degassing rates allowed structural and mechanistic interpretation of the degassing process.

Understanding the Effects of Roasting on Antioxidant Components of Coffee Brews by Coupling On-line ABTS Assay to High Performance Size Exclusion Chromatography.

INTRODUCTION: Coffee is a widely consumed beverage containing antioxidant active compounds. During roasting the phytochemical composition of the coffee bean changes dramatically and highly polymeric substances are produced. Besides chlorogenic acids that are already present in green coffee beans, melanoidins show antioxidant capacity as well. OBJECTIVE: To employ post-column derivatisation by coupling high performance size exclusion chromatography (HPSEC) to an antioxidant assay to investigate the effect of roasting on the properties of antioxidant active compounds in coffee brews. METHODOLOGY: We have investigated the antioxidant capacity of Coffea arabica (Arabica) and C. canephora (Robusta) beans that were roasted over the full spectrum of roast conditions (four roasting speeds to three roast degrees) by comparing the results from HPSEC coupled on-line to the ABTS assay with those from two batch assays, Folin Ciocalteu (FC) and oxygen radical absorbance capacity (ORAC) assay. RESULTS: The antioxidant capacity showed a general decrease towards slower and darker roasted coffee for all three assays, indicative of heat degradation of active compounds. Hence, low molecular weight (LMW) compounds such as chlorogenic acids (CGAs) decreased progressively already from relatively mild roasting conditions. In contrast, high molecular weight (HMW) compounds (e.g. melanoidins) increased from light to dark roast degrees with lowering magnitude towards slower roasting profiles. CONCLUSION: By coupling HPSEC on-line to the ABTS assay we were able to separately quantify the contribution of HMW and LMW compounds to the total antioxidant capacity, increasing our understanding of the roast process. © 2016 The Authors. Phytochemical Analysis Published by John Wiley & Sons Ltd.

Large fractions of CO2-fixing microorganisms in pristine limestone aquifers appear to be involved in the oxidation of reduced sulfur and nitrogen compounds.

The traditional view of the dependency of subsurface environments on surface-derived allochthonous carbon inputs is challenged by increasing evidence for the role of lithoautotrophy in aquifer carbon flow. We linked information on autotrophy (Calvin-Benson-Bassham cycle) with that from total microbial community analysis in groundwater at two superimposed-upper and lower-limestone groundwater reservoirs (aquifers). Quantitative PCR revealed that up to 17% of the microbial population had the genetic potential to fix CO2 via the Calvin cycle, with abundances of cbbM and cbbL genes, encoding RubisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) forms I and II, ranging from 1.14 × 10(3) to 6 × 10(6) genes liter(-1) over a 2-year period. The structure of the active microbial communities based on 16S rRNA transcripts differed between the two aquifers, with a larger fraction of heterotrophic, facultative anaerobic, soil-related groups in the oxygen-deficient upper aquifer. Most identified CO2-assimilating phylogenetic groups appeared to be involved in the oxidation of sulfur or nitrogen compounds and harbored both RubisCO forms I and II, allowing efficient CO2 fixation in environments with strong oxygen and CO2 fluctuations. The genera Sulfuricella and Nitrosomonas were represented by read fractions of up to 78 and 33%, respectively, within the cbbM and cbbL transcript pool and accounted for 5.6 and 3.8% of 16S rRNA sequence reads, respectively, in the lower aquifer. Our results indicate that a large fraction of bacteria in pristine limestone aquifers has the genetic potential for autotrophic CO2 fixation, with energy most likely provided by the oxidation of reduced sulfur and nitrogen compounds.

Oxygen availability and distance to surface environments determine community composition and abundance of ammonia-oxidizing prokaroytes in two superimposed pristine limestone aquifers in the Hainich region, Germany.

We followed the abundance and compared the diversity of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in the groundwater of two superimposed pristine limestone aquifers located in the Hainich region (Thuringia, Germany) over 22 months. Groundwater obtained from the upper aquifer (12 m depth) was characterized by low oxygen saturation (0-20%) and low nitrate concentrations (0-20 µM), contrasting with 50-80% oxygen saturation and 40-200 µM nitrate in the lower aquifer (48 m and 88 m depth). Quantitative PCR targeting bacterial and archaeal amoA and 16S rRNA genes suggested a much higher ammonia oxidizer fraction in the lower aquifer (0.4-7.8%) compared with the upper aquifer (0.01-0.29%). In both aquifers, AOB communities were dominated by one phylotype related to Nitrosomonas ureae, while AOA communities were more diverse. Multivariate analysis of amoA DGGE profiles revealed a stronger temporal variation of AOA and AOB community composition in the upper aquifer, pointing to a stronger influence of surface environments. Parallel fluctuations of AOA, AOB, and total microbial abundance suggested that hydrological factors (heavy rain falls, snow melt) rather than specific physicochemical parameters were responsible for the observed community dynamics.

Antioxidant Generation during Coffee Roasting: A Comparison and Interpretation from Three Complementary Assays.

Coffee is a major source of dietary antioxidants; some are present in the green bean, whereas others are generated during roasting. However, there is no single accepted analytical method for their routine determination. This paper describes the adaption of three complementary assays (Folin-Ciocalteu (FC), ABTS and ORAC) for the routine assessment of antioxidant capacity of beverages, their validation, and use for determining the antioxidant capacities of extracts from coffee beans at different stages in the roasting process. All assays showed a progressive increase in antioxidant capacity during roasting to a light roast state, consistent with the production of melanoidins having a higher antioxidant effect than the degradation of CGAs. However, the three assays gave different numbers for the total antioxidant capacity of green beans relative to gallic acid (GA), although the range of values was much smaller when chlorogenic acid (CGA) was used as reference. Therefore, although all three assays indicated that there was an increase in antioxidant activity during coffee roasting, and the large differences in responses to GA and CGA illustrate their different sensitivities to different types of antioxidant molecule.

Exploring the nitrogen ingestion of aphids--a new method using electrical penetration graph and (15)N labelling.

Studying plant-aphid interactions is challenging as aphid feeding is a complex process hidden in the plant tissue. Here we propose a combination of two well established methods to study nutrient acquisition by aphids focusing on the uptake of isotopically labelled nitrogen ((15)N). We combined the Electrical Penetration Graph (EPG) technique that allows detailed recording of aphid feeding behaviour and stable isotope ratio mass spectrometry (IRMS) to precisely measure the uptake of nitrogen. Bird cherry-oat aphids Rhopalosiphum padi L. (Hemiptera, Aphididae) fed for 24 h on barley plants (Hordeum vulgare L., cultivar Lina, Poaceae) that were cultivated with a (15)N enriched nutrient solution. The time aphids fed in the phloem was strongly positive correlated with their (15)N uptake. All other single behavioural phases were not correlated with (15)N enrichment in the aphids, which corroborates their classification as non-feeding EPG phases. In addition, phloem-feeding and (15)N enrichment of aphids was divided into two groups. One group spent only short time in the phloem phase and was unsuccessful in nitrogen acquisition, while the other group displayed longer phloem-feeding phases and was successful in nitrogen acquisition. This suggests that several factors such as the right feeding site, time span of feeding and individual conditions play a role for the aphids to acquire nutrients successfully. The power of this combination of methods for studying plant-aphid interactions is discussed.

How does roasting affect the antioxidants of a coffee brew? Exploring the antioxidant capacity of coffee via on-line antioxidant assays coupled with size exclusion chromatography.

During coffee roasting major changes occur in coffee bean composition. Among others dark coloured melanoidins are formed, which are high molecular weight Maillard reaction products. A new approach is presented here to monitor the influence of roasting conditions on the antioxidant capacity of melanoidins and chlorogenic acids (CGAs) in a coffee brew. Validated Folin-Ciocalteu (FC) and ABTS assays were used as on-line antioxidant assays coupled (post-column) with high performance size-exclusion chromatography (HPSEC). HPSEC enabled the separation of melanoidins from CGAs and the determination of the antioxidant capacity of each fraction, within a total elution time of 25 min. Besides the on-line assay measurements, both assays were also applied off-line with flow injection analysis (FIA). The maximum antioxidant capacity was determined to be at a light-to-medium roast degree, measured with both ABTS-FIA and FC-FIA assays as well as on-line ABTS assay. With FC on-line assay the maximum was found to be at a very light roast degree. Based on the peak areas obtained with the new coupled technique the roasting effects on the variability of melanoidin and CGA contents in coffee brews were studied. The majority of melanoidins are already formed in the early stage of the roasting process and the relative contribution of melanoidins to the total antioxidant capacity increases towards darker roasts, mainly because CGAs degrade during roasting. A new parameter, the ratio of melanoidin to CGA peak area, was introduced as a possible predictor of the roast degree.

Host shifts from Lamiales to Brassicaceae in the sawfly genus Athalia.

Plant chemistry can be a key driver of host shifts in herbivores. Several species in the sawfly genus Athalia are important economic pests on Brassicaceae, whereas other Athalia species are specialized on Lamiales. These host plants have glucosides in common, which are sequestered by larvae. To disentangle the possible direction of host shifts in this genus, we examined the sequestration specificity and feeding deterrence of iridoid glucosides (IGs) and glucosinolates (GSs) in larvae of five species which either naturally sequester IGs from their hosts within the Plantaginaceae (Lamiales) or GSs from Brassicaceae, respectively. Furthermore, adults were tested for feeding stimulation by a neo-clerodane diterpenoid which occurs in Lamiales. Larvae of the Plantaginaceae-feeders did not sequester artificially administered p-hydroxybenzylGS and were more deterred by GSs than Brassicaceae-feeders were by IGs. In contrast, larvae of Brassicaceae-feeders were able to sequester artificially administered catalpol (IG), which points to an ancestral association with Lamiales. In line with this finding, adults of all tested species were stimulated by the neo-clerodane diterpenoid. Finally, in a phylogenetic tree inferred from genetic marker sequences of 21 Athalia species, the sister species of all remaining 20 Athalia species also turned out to be a Lamiales-feeder. Fundamental physiological pre-adaptations, such as the establishment of a glucoside transporter, and mechanisms to circumvent activation of glucosides by glucosidases are therefore necessary prerequisites for successful host shifts between Lamiales and Brassicaceae.

Desulfation followed by sulfation: metabolism of benzylglucosinolate in Athalia rosae (Hymenoptera: Tenthredinidae).

The sawfly species Athalia rosae (L.) (Hymenoptera: Tenthredinidae) is phytophagous on plants of the family Brassicaceae and thus needs to cope with the plant defence, the glucosinolate-myrosinase system. The larvae sequester glucosinolates in their haemolymph. We investigated how these compounds are metabolized by this specialist. When larvae were fed with ([(14) C]-labelled) benzylglucosinolate, one major degradation metabolite, with the same sum formula as benzylglucosinolate, was defecated. This metabolite was also found in the haemolymph along with desulfobenzylglucosinolate, which continuously increased in concentration. NMR spectroscopy in conjunction with LC-TOF-MS measurements revealed the major degradation metabolite to be desulfobenzylglucosinolate-3-sulfate, probably converted from desulfobenzylglucosinolate after sulfation at the sugar moiety. The enzymes responsible must be located in the haemolymph. Additionally, a putative sulfotransferase forms benzylglucosinolate sulfate in the gut from intact, non-sequestered glucosinolate. The corresponding desulfoglucosinolate sulfates were also detected in faeces after feeding experiments with phenylethylglucosinolate and prop-2-enylglucosinolate, which indicates a similar degradation mechanism for various glucosinolates in the larvae. This is the first report on glucosinolate metabolism of a glucosinolate-sequestering insect species.

Sequestration of glucosinolates and iridoid glucosides in sawfly species of the genus Athalia and their role in defense against ants.

In this study, the larval sequestration abilities and defense effectiveness of four sawfly species of the genus Athalia (Hymenoptera: Tenthredinidae) that feed as larvae either on members of the Brassicaceae or Plantaginaceae were investigated. Brassicaceae are characterized by glucosinolates (GLSs), whereas Plantaginaceae contain iridoid glucosides (IGs) as characteristic secondary compounds. Athalia rosae and A. liberta feed on members of the Brassicaceae. Larvae of A. rosae sequester aromatic and aliphatic GLSs of Sinapis alba in their hemolymph, as shown previously, but no indolic GLSs; A. liberta larvae with a narrower host range sequester aliphatic as well as indolic GLSs from their host plant Alliaria petiolata. Larvae of A. circularis and A. cordata are specialized on members of the Plantaginaceae. Athalia circularis utilizes mainly Veronica beccabunga as host plant, whereas A. cordata feeds additionally on Plantago lanceolata. Both sawfly species sequester the IGs aucubin and catalpol. In V. beccabunga, catalpol esters and carboxylated IGs also occur. The high catalpol concentrations in hemolymph of A. circularis can only be explained by a metabolization of catalpol esters and subsequent uptake of the resulting catalpol. The carboxylated IGs of the plant are excreted. The IG-sequestering sawfly species are able to accumulate much higher glucoside concentrations in their hemolymph than the GLS-sequestering species, and the concentration of IGs in hemolymph increases constantly during larval development. The defensive effectiveness of hemolymph that contains GLSs or IGs and of the respective glucosides was tested in feeding-bioassays against a potential predator, the ant Myrmica rubra (Hymenoptera: Formicidae). Hemolymph of IG-sequestering cryptic A. cordata larvae has a higher deterrence potential than hemolymph of the GLS-sequestering conspicuous A. rosae larvae. The results show that glucoside sequestration is widespread in the genus Athalia, but that the specific glucoside uptake can result in different defense effectiveness against a predator species.