Optimized lipid extraction and annotation pipeline customization for individual chitinous mesozooplankton using UPLC-HRMS

Comparison of electrospray and UniSpray™ ion sources with post-column hydrochloric acid infusion for 119 abuse relevant substances

Despite escalating anthropogenic alteration of food webs, how the carbon cycle in ecosystems is regulated by food web processes remains poorly understood. We quantitatively synthesize the effects of consumers (herbivores, omnivores and carnivores) on the carbon cycle of coastal wetland ecosystems, 'blue carbon' ecosystems that store the greatest amount of carbon per unit area among all ecosystems. Our results reveal that consumers strongly affect many processes of the carbon cycle. Herbivores, for example, generally reduce carbon absorption and carbon stocks (e.g. aboveground plant carbon by 53% and aboveground net primary production by 23%) but may promote some carbon emission processes (e.g. litter decomposition by 32%). The average strengths of these effects are comparable with, or even times higher than, changes driven by temperature, precipitation, nitrogen input, CO2 concentration, and plant invasions. Furthermore, consumer effects appear to be stronger on aboveground than belowground carbon processes and vary markedly with trophic level, body size, thermal regulation strategy and feeding type. Despite important knowledge gaps, our results highlight the powerful impacts of consumers on the carbon cycle and call for the incorporation of consumer control into Earth system models that predict anthropogenic climate change and into management strategies of Earth's carbon stocks. This article is part of the theme issue 'Integrative research perspectives on marine conservation'.

It is demonstrated that the signal intensity in a RARE (TSE, FS...)-sequence with low refocusing flip angle alpha can be significantly increased by setting the flip angle of the first refocusing pulse to 90 degrees +alpha/2. In addition to the gain in signal intensity, the initial signal modulations over the first few echoes are reduced compared to a CPMG-echo train with constant alpha.

Microalgae are well considered to be promising feedstocks for biodiesel production. Microalgae can be grown under different types of cultivation conditions and their biomass has tremendous potential to be used as biofuel feedstock and for other applications such as feed, food, cosmetics, pharmaceutical etc. Despite the many benefits and the significant development in the field of microalgal biodiesel production, there are several challenges including high cultivation cost and developing efficient downstream processing methods. The biomass production cost is high, which significantly hinders the use of microalgae as a feedstock. Most of the available literature is focused on upstream, single strain and single product strategy, where mainly algal lipids are used for biofuel production. Hence, for improving the sustainability of the algal biofuel production processes and related process economics, a multiple applications approach using integrated biorefinery and exploiting microalgae for environmental benefits is required. To explore the microalgal biorefinery concept it is vital to understand the various cultivation conditions and applications of biomass in different sectors. There are various strategies, which have potential to make algal biofuel technologies more economically feasible and environmentally sustainable. Use of alternative culture media, improving the biomass production and the efficiency of downstream processing (drying, cell disruption, lipid extraction etc.) algal biofuel technology economical. Utilizing lipid-extracted algae (LEA) for energy and aqua feed application will maximize overall economic return and will leave minimal residues as by-product. The major focus of this thesis was to utilize LEA as substrate for biomethane production and protein source in aquaculture feed. However, effect of preceding steps such as microalgae cultivation, biomass drying and cell disruption on major metabolites extraction was also studied. Microalgae were cultivated in different medium (domestic wastewater and BG11) and their biomass yields and biochemical composition (lipid, protein and carbohydrate) were compared. Different drying and cell disruption techniques were employed for lipid extraction and their effect on lipid, protein and carbohydrate yields were evaluated. The yield of major metabolites on whole cell and LEA were also compared. Suitable solvent systems were selected for optimum lipid extraction from wet and dry biomass with minimal toxic effect on LEA metabolites so that LEA can be further used for biomethane and aquaculture feed production. The choice of microalgae at large scale depends upon the number of factors such as their adaptability to large-scale cultivation, biomass production, major metabolites content, robustness towards the open system cultivation and contamination. In this study, S. obliquus and C. sorokiniana were cultivated in wastewater and BG11 medium at laboratory scale. Both strains are indigenous to KwaZulu-Natal. C. sorokiniana showed lower biomass and major metabolites (lipid, protein and carbohydrate) production at large scale compared to S. obliquus. Considering better adaptability to open cultivation, high biomass and metabolites yields, S. obliquus strain was selected for the LEA application study. Microalgae species, C. sorokiniana and S. obliquus were cultivated on BG11 and using different ratios of raw domestic wastewater and post-chlorinated wastewater as nutrient media. The cultivation of S. obliquus and C. sorokiniana showed biomass yield of 1.2-3.5 and 0.78-1.8 g L-1 in BG11 medium, respectively. While biomass yield observed in wastewater was 0.59-1.59 g L-1 for S. obliquus and 0.67-1.45 g L-1 for C. sorokiniana. The higher biomass yield in BG11 medium attributed to the higher nutrient contents in this medium compared to wastewater. The lipid contents for S. obliquus and C. sorokiniana were 20 and 16.5% dry cell weight (DCW), respectively when grown using BG11 medium. While increases in lipid contents of 26.25 and 29.4% DCW were found for S. obliquus and C. sorokiniana, respectively when cultivated using wastewater. Similarly, carbohydrate contents for S. obliquus and C. sorokiniana were 18 and 17% DCW, respectively for BG11 medium. Increased in carbohydrate contents of 25% for S. obliquus, 28.4% DCW for C. sorokiniana were observed for wastewater. Microalgae tend to accumulate more lipids and/or carbohydrates under nutrient stress condition. The nitrogen and phosphorus contents in wastewater are lower than BG11 medium, which were responsible for stressed condition for microalgae. With limited nutrients in wastewater compared to BG11 medium, growth of microalgae is also lower which resulted in lower protein content. Protein content for S. obliquus and C. sorokiniana in BG11 medium were 37.83-48.8 and 25-35.3% DCW, respectively. The protein contents for S. obliquus and C. sorokiniana in wastewater medium were 16.4-27.29 and 15.8-27.3% DCW, respectively. The biochemical composition depends upon the nutrient composition of the medium and cultivation conditions. The two selected microalgae have shown potential for nutrient removal while cultivated in wastewater. The removal efficiency by S. obliquus was found to be 76.13% for COD, 98.54% for nitrogen and 97.99% for phosphate. Microalgae C. sorokiniana cultivation in wastewater removed 69.38% COD, 86.93% nitrogen and 68.24% phosphates. Increased lipid accumulation in the cells was also recorded in stressed conditions due to low nutrient availability from wastewater. After harvesting of microalgae from culture media, the water content in thick algal slurry (>85% DCW) lowers the products recovery. To overcome this challenge drying and cell disruption are required to enhance the efficiency of lipid extraction. Where drying and cell disruption increase the viability of biomass for lipid extraction process. Three biomass-drying techniques viz. sun, oven and freeze-drying and four-cell disruption techniques viz. microwave, sonication, osmotic shock and autoclave disruption were studied for their effect on recovery of major metabolites from S. obliquus. Microalgae metabolites recovery from whole cell and LEA were analysed and compared. The results showed that after lipid extraction, LEA still contained comparable protein to whole algae biomass however, the carbohydrate concentration was reduced. Oven drying exhibited the highest recovery of all the major metabolites followed by freeze-drying; sun drying however, showed lower yields. Despite lower metabolites recovery sun-drying technique is preferable at large scale due to its easy application and cost-effective nature. The main drawback of sun drying technique is weather dependence and required longer period to dry. The microwave and autoclave microalgal cell disruption improved the lipid yield but loss of other compounds was observed. In osmotic shock treatment, due to poor cell disruption efficiency low lipid were obtained and comparably lower protein loss was noticed during lipid extraction. Lipid extraction is crucial step for microalgae biodiesel production. Solvent-assisted lipid extraction is widely used technique for lipid recovery from dry or wet algae biomass. In a biorefinery approach, it is vital to choose appropriate solvents for the optimum lipid extraction whilst having minimal effect on the remaining metabolites (protein and carbohydrates) in LEA. LEA could be used for energy generation or aquaculture feed applications. Six commonly used organic solvents/ solvent systems were used for lipid extraction from wet and dry biomass. The results showed that the lipid extraction efficiency depends strongly on types of biomass as well as solvent systems selected. Lipid extraction from wet algal biomass could reduce the processing steps and save energy incurred in drying. However, the water present in wet algal slurry acts as a barrier, which results in lower lipid yield compared to the dry biomass. The results revealed that among all six-selected solvents, chloroform: ethanol (1:1 v/v) was most effective if wet biomass used specifically for lipid purpose only. To explore the biorefinery concept, isopropanol/hexane composition is the most suitable solvent system because it is less toxic and resulted in high protein (20.07% DCW) and carbohydrate (22.87%) yields in LEA. For dry algal biomass, chloroform: methanol (2:1 v/v) is an appropriate solvent system if biomass used especially for lipid (19.25%) extraction. If LEA to be used for energy and/or aquaculture feed application, DCM: methanol was found to be a suitable solvent system, which gave 32.79% protein and 26.92% carbohydrate yield. Comparatively hexane has lower lipid recovery but shown higher protein and carbohydrate yield in LEA. Due to less toxic, easy to scale up and inexpensive, hexane is preferable as a solvent for lipid extraction if LEA is to be further utilized at large scale for energy or feed application. Anaerobic digestion (AD) of organic residues is well-researched technology for biomethane production. Whole microalgae and LEA has promising potential for biomethane production. The anaerobic sludge used as inoculum for microalgal biomass digestion. Biomethane production from whole algae and products extracted algae highly depends on sludge to algae biomass ratio for higher methane production. The extraction of metabolites also changes the biochemical composition of residual biomass, which can affect the biomethane production. It is vital to understand the effect of various product-extracted algae and as well as pre-treated algae on the biochemical methane potential. In order to compare biomethane potential, four types of biomass were selected namely sun dried powder algae (SDPA), mild heat-treated algae (MHTA), LEA (using hexane as lipid extracting solvent) and protein-extracted algae (PEA). The average methane (CH4) production rate was ~ 2.5 times higher for protein and lipid ex

Modulation-aided signal enhancement in the magic angle spinning NMR of spin-5/2 nuclei

Analytical method for ubiquinone-9 and ubiquinone-10 in rat tissues by liquid chromatography/turbo ion spray tandem mass spectrometry with 1-alkylamine as an additive to the mobile phase

Recent years have confirmed the ubiquitous applicability of lateral flow assays (LFA) in point-of-care testing (POCT). To make this technology available for low abundance analytes, strategies towards lower limits of detections (LOD), while maintaining the LFA’s ease of use, are still being sought. Here, we demonstrate how liposomes can significantly improve the LOD of traditional gold nanoparticle (AuNP)–based assays while fully supporting a ready-to-use system for commercial application. We fine-tuned liposomes towards photometric and fluorescence performance on the synthesis level and applied them in an established interleukin 6 (IL-6) immunoassay normally using commercial AuNP labels. IL-6’s low abundance (< 10 pg mL−1) and increasing relevance as prognostic marker for infections make it an ideal model analyte. It was found that liposomes with a high encapsulant load (150 mmol L−1 sulforhodamine B (SRB)) easily outperform AuNPs in photometric LFAs. Specifically, liposomes with 350 nm in diameter yield a lower LOD even in complex matrices such as human serum below the clinically relevant range (7 pg mL−1) beating AuNP by over an order of magnitude (81 pg mL−1). When dehydrated on the strip, liposomes maintained their signal performance for over a year even when stored at ambient temperature and indicate extraordinary stability of up to 8 years when stored as liquid. Whereas no LOD improvement was obtained by exploiting the liposomes’ fluorescence, an extraordinary gain in signal intensity was achieved upon lysis which is a promising feature for high-resolution and low-cost detection devices. Minimizing the procedural steps by inherently fluorescent liposomes, however, is not feasible. Finally, liposomes are ready for commercial applications as they are easy to mass-produce and can simply be substituted for the ubiquitously used AuNPs in the POCT market.Graphical abstract

An intermediate electrode was developed to improve the transfer of ions in atmospheric pressure from a first location, the ion source, to a second location, the mass spectrometer. The new apparatus increase the efficiency of mass analysis of molecular constituents of liquids, including trace analysis of chemical entities, in which an electrospray (ES) or IonSpray™ (IS) technique is used to produce electrically charged droplets which divide and evaporate to form gaseous ions of the molecular constituents. The gas phase ions are transported to the mass spectrometer by an electric field generated by a new electrode design that separates the two fundamental functions of an electrospray or an IonSpray™, which are the nebulization of charged droplets and the transport of ions into the mass analyzer. The results suggest that the new apparatus provide a gain in signal intensity up to 10 compared with the commercial product. A significant improvement in ion transport results in higher precision and accuracy and/or reduction of the amount of material needed for analysis.

INADEQUATE-CR Experiments in the Solid State

Nanostructures of polyvinyledenedifluoride-tetrafluoroethylene (PVDF-TrFE), a semicrystalline polymer with high piezoelectricity, results in significant enhancement of crystallinity and better device performance as sensors, actuators, and energy harvesters. Using electrospinning of PVDF to manufacture nanofibers, we demonstrate a new method to pattern high-density, highly aligned nanofibers. To further boost the charge transfer from such a bundle of nanofibers, we fabricated novel core-shell structures. Finally, we developed pressure sensors utilizing these fiber structures for endovascular applications. The sensors were tested in vitro under simulated physiological conditions. We observed significant improvements using core-shell electrospun fibers (4.5 times gain in signal intensity, 4000 μV/mmHg sensitivity) over PVDF nanofibers (280 μV/mmHg). The preliminary results showed that core-shell fiber-based devices exhibit nearly 40-fold higher sensitivity, compared to the thin-film structures demonstrated earlier.

Comparative evaluation of SARS-CoV-2 antigens as capture and detection elements in an in-house antigen-based ELISA for COVID-19 total antibody detection.

In mass spectrometry, the type and design of ionization source play a key role on the performance of a given instrument. Therefore, it is of paramount importance to evaluate newly developed sources for their suitability to analyze food contaminants like pesticide residues. Here, we carried out a head-to-head comparison of key extraction and analytical performance parameters of an electrospray ionization (ESI) source with a new atmospheric pressure ionization source, UniSpray (US). The two interfaces were evaluated in three matrices of different properties (coffee, apple, and water) to determine if multiresidue analysis of 81 pesticides by QuEChERS extraction and LC-MS/MS analysis could be improved. Depending on the matrix and irrespective of the chemical class, US provided a tremendous gain in signal intensity (22- to 32-fold in peak area, 6- to 7-fold in peak height), a threefold to fourfold increase in signal-to-noise ratio, a mild gain in the range of compounds that can be quantified, and up to twofold improvement of recovery. UniSpray offered comparable linearity and precision of the analyses with ESI, and did not affect the ion ratio. A gain in sensitivity of many compounds was observed with US, but in general, the two ionization interfaces did not show significant difference in LOD and LOQ. UniSpray suffered less signal suppression; the matrix effect was in average 3 to 4 times more pronounced, but showed better values than ESI. With no effect on recovery efficiency, US improved the overall process efficiency 3 to 4 times more than ESI.Graphical abstract

Contrast of trueFISP images depends mainly on the T2/T1 ratio. Consequently, there is a potential gain in signal intensity after administration of paramagnetic contrast medium despite the strong T2 weighting. The purpose of this study was to analyze signal intensities of abdominal organs after applying contrast medium and to determine whether this yields an improved contrast for pathologies compared with precontrast trueFISP. Fifty patients underwent an abdominal examination, including the trueFISP sequence before and after the administration of contrast medium. All images were obtained with a 1.5 T system. The mean signal-to-noise ratio before and after contrast medium was assessed for abdominal organs, vessels, muscle, and fat. The contrast-to-noise ratio (CNR) of pathologic lesions was calculated. The trueFISP sequence yielded a higher signal-to-noise ratio after application of contrast medium for all organs except for fat and the aorta. CNR of solid lesions (angiomyolipoma, liver adenoma, liver hemangioma, hepatocellular carcinoma) increased whereas contrast of cysts decreased. TrueFISP imaging after application of contrast medium led to better CNR for many solid lesions while cysts showed a diminished contrast. We advise trueFISP imaging sequences before and after contrast medium application.

Two single-shot localization techniques, STEAM and PRESS, are analyzed with regard to specifications for in vivo localized proton NMR. In particular, attention is paid to optimum signal intensity per unit volume, sensitivity to motion and diffusion, shortest attainable echo time, water suppression and editing possibilities. Experimental results are shown for cat brain at 4.7 T and human brain at 1.5 T. Both STEAM and PRESS are highly effective localization methods. For long echo times, PRESS is the method of choice, because it offers a factor of two gain in signal intensity. In addition, the method is less sensitive to motion and diffusion, and not susceptible to multiple-quantum effects. STEAM offers advantages for observation of (coupled) metabolites with short T2, because (a) shorter TEs can be attained and (b) effective water suppression sequences can be implemented without penalty in echo time. Differences relating to editing possibilities and B1 dependence, possibly important in choosing a method, are discussed.

Signal loss and absolute quantitation errors in 1H-MRS (localized proton MR spectroscopy) because of physiologic brain motion are analyzed quantitatively. Cardiac and respiratory related motion lead to substantial phase dispersion when using a standard, short echo-time STEAM sequence. The loss in signal area varies from 6-7% with TM (middle interval time in a STEAM sequence) = 13.7 ms, to 25-39% with TM = 100 ms. The variation in signal area because of motion-related phase dispersion is up to 16% for TM = 100 ms. The signal phase as a function of the position in the cardiac cycle is shown to be reproducible. Maximal differences in the signal phase are over 180 degrees for long TMs. ECG-gating reduces the phase dispersion considerably but introduces problems with variable repetition times. Using a phase calibration curve recorded with the water suppression turned off, it is possible to retrogate subsequent untriggered acquisitions with the water suppression activated, if the time points in the cardiac cycle are recorded for each acquisition. The gain in signal intensity is between 3 and 21%. For absolute quantification via brain water, this phase analysis has the important consequence that reference scans must be phased individually before co-adding, otherwise metabolite concentrations may be severely overestimated.