Acid-based deep eutectic solvents followed by GFAAS for the speciation of As(III), As(V), total inorganic arsenic and total arsenic in rice samples.

In the present study, an efficacious, safe, inexpensive and eco-friendly microextraction was provided by deep eutectic solvents based on dispersive liquid-liquid microextraction (DLLME - DES) followed by GFAAS. A series of DESs were synthesised using l-menthol as hydrogen bond acceptor (HBA) and carboxylic acids with 4, 6, 8 and 10 carbon atoms as hydrogen bond donors (HBD). The synthesised DESs were used as extractants of arsenic ions. Under optimised conditions, good linearity with coefficient of determination (r2) 0.992 and an acceptable linear range of 0.3-100 µg kg-1 was obtained. The limit of detection was 0.1 µg kg-1 (S/N = 3) for arsenite (As(III)) ions, and a high enrichment factor (EF = 200) was obtained. The enhancement factor and extraction recovery (ER%) of the method were 340 and 60%, respectively. RSDs including inter- and intra-day ranged from 3.2% to 5.8% in three examined concentrations. After a specific digestion, the capability of the synthesised DES in the extraction of As(III) from rice was tested. Total inorganic arsenic was separated similarly after reduction of arsenate (As(V)) to As(III), and As(V) concentration was calculated by difference. Using a second digestion method, total arsenic concentration (sum of organic and inorganic arsenic) in the samples was determined.

Compartmentalization of lutein in simple and double emulsions containing protein nanoparticles: Effects on stability and bioaccessibility.

Delivery systems designed through protein stabilized emulsions are promising for incorporating carotenoids in different products. Nevertheless, the versatility in structures of such systems raises questions regarding the effect of the bioactive compound localization on their bio-efficacy, in particular for double emulsions. In this context, the aims of this study were to determine the impact of the localization of lutein in different water/oil/water double emulsions versus a single oil/water emulsion on the stability and in vitro bioaccessibility of lutein, a lipophilic carotenoid. The inner aqueous phase, which contained whey protein isolate (WPI) nanoparticles obtained by desolvation, was emulsified in sunflower oil stabilized by polyglycerol polyricinoleate (PGPR). The primary emulsion was then emulsified in a continuous aqueous phase containing whey protein isolate (WPI) and xanthan gum, the latter to increase the viscosity of the outer phase and delay creaming. Lutein was incorporated using different strategies: (1) lutein entrapped by WPI nanoparticles within the inner water phase of a double emulsion (W-L/O/W); (2) lutein incorporated into the oil phase of the double emulsion (W/O-L/W); (3) lutein incorporated in the oil phase of a single emulsion (O-L/W). All systems contained similar whey protein concentrations, as well as all other stabilizers. W-L/O/W sample showed the lowest lutein stability against light exposure during storage, and the highest lutein bioaccessibility after in vitro digestion, for freshly made samples. Furthermore, the in vitro bioaccessibility of lutein incorporated into the single emulsion was considerably lower than those observed for the double emulsions. The results reinforce the importance of designing appropriate structures for delivering improved stability and bioaccessibility of bioactive compounds.

Arteriovenous thrombosis, a complication of induction therapy with all-trans retinoic acid for acute promyelocytic leukemia: A case report.

We report a case of arterial and venous thrombosis during induction therapy. This case emphasizes considering some degree of caution for thrombotic events in APL patients which was represented in our case as abdominal pain. Rapid initiation of anticoagulation and preventive measures is suggested for better management of the condition.

Coupling in vitro food digestion with in vitro epithelial absorption; recommendations for biocompatibility.

As food transits the gastrointestinal tract, food structures are disrupted and nutrients are absorbed across the gut barrier. In the past decade, great efforts have focused on the creation of a consensus gastrointestinal digestion protocol (i.e., INFOGEST method) to mimic digestion in the upper gut. However, to better determine the fate of food components, it is also critical to mimic food absorption in vitro. This is usually performed by treating polarized epithelial cells (i.e., differentiated Caco-2 monolayers) with food digesta. This food digesta contains digestive enzymes and bile salts, and if following the INFOGEST protocol, at concentrations that although physiologically relevant are harmful to cells. The lack of a harmonized protocol on how to prepare the food digesta samples for downstream Caco-2 studies creates challenges in comparing inter laboratory results. This article aims to critically review the current detoxification practices, highlight potential routes and their limitations, and recommend common approaches to ensure food digesta is biocompatible with Caco-2 monolayers. Our ultimate aim is to agree a harmonized consensus protocol or framework for in vitro studies focused on the absorption of food components across the intestinal barrier.

Semi-rational Engineering of a Promiscuous Fatty Acid Hydratase for Alteration of Regioselectivity.

Fatty acid hydratases (FAHs) catalyze regio- and stereo-selective hydration of unsaturated fatty acids to produce hydroxy fatty acids. Fatty acid hydratase-1 (FA-HY1) from Lactobacillus Acidophilus is the most promiscuous and regiodiverse FAH identified so far. Here, we engineered binding site residues of FA-HY1 (S393, S395, S218 and P380) by semi-rational protein engineering to alter regioselectivity. Although it was not possible to obtain a completely new type of regioselectivity with our mutant libraries, a significant shift of regioselectivity was observed towards cis-5, cis-8, cis-11, cis-14, cis-17-eicosapentaenoic acid (EPA). We identified mutants (S393/S395 mutants) with excellent regioselectivity, generating a single hydroxy fatty acid product from EPA (15-OH product), which is advantageous from application perspective. This result is impressive given that wild-type FA-HY1 produces a mixture of 12-OH and 15-OH products at 63 : 37 ratio (12-OH : 15-OH). Moreover, our results indicate that native FA-HY1 is at its limit in terms of promiscuity and regiospecificity, thus it may not be possible to diversify its product portfolio with active site engineering. This behavior of FA-HY1 is unlike its orthologue, fatty acid hydratase-2 (FA-HY2; 58 % sequence identity to FA-HY1), which has been shown earlier to exhibit significant promiscuity and regioselectivity changes by a few active site mutations. Our reverse engineering from FA-HY1 to FA-HY2 further demonstrates this conclusion.

Rhodopsin-based voltage imaging tools for use in muscles and neurons of Caenorhabditis elegans.

Genetically encoded voltage indicators (GEVIs) based on microbial rhodopsins utilize the voltage-sensitive fluorescence of all-trans retinal (ATR), while in electrochromic FRET (eFRET) sensors, donor fluorescence drops when the rhodopsin acts as depolarization-sensitive acceptor. In recent years, such tools have become widely used in mammalian cells but are less commonly used in invertebrate systems, mostly due to low fluorescence yields. We systematically assessed Arch(D95N), Archon, QuasAr, and the eFRET sensors MacQ-mCitrine and QuasAr-mOrange, in the nematode Caenorhabditis elegans ATR-bearing rhodopsins reported on voltage changes in body wall muscles (BWMs), in the pharynx, the feeding organ [where Arch(D95N) showed approximately 128% ΔF/F increase per 100 mV], and in neurons, integrating circuit activity. ATR fluorescence is very dim, yet, using the retinal analog dimethylaminoretinal, it was boosted 250-fold. eFRET sensors provided sensitivities of 45 to 78% ΔF/F per 100 mV, induced by BWM action potentials, and in pharyngeal muscle, measured in simultaneous optical and sharp electrode recordings, MacQ-mCitrine showed approximately 20% ΔF/F per 100 mV. All sensors reported differences in muscle depolarization induced by a voltage-gated Ca2+-channel mutant. Optogenetically evoked de- or hyperpolarization of motor neurons increased or eliminated action potential activity and caused a rise or drop in BWM sensor fluorescence. Finally, we analyzed voltage dynamics across the entire pharynx, showing uniform depolarization but compartmentalized repolarization of anterior and posterior parts. Our work establishes all-optical, noninvasive electrophysiology in live, intact C. elegans.