Microwave-assisted deep eutectic solvents/dimethyl sulfoxide system for efficient valorization of sugar bagasse waste into platform chemicals: A biorefinery approach for circular bioeconomy

The exploitation of lignocellulosic biomass (LB) such as sugar bagasse waste in biorefineries is the most cost-effective and favourable sustainable approach to producing essential platform chemicals, materials, and energy environmentally benignly. Herein, a microwave-mediated deep eutectic solvents (DESs)/dimethyl sulfoxide (DMSO) system for efficiently processing LB waste into platform chemicals was proposed thereof. Under optimized appropriate diverse parameters such as solvent varieties, catalyst dosage, DMSO addition, reaction time and temperature, the proposed catalytic system (i.e., microwave mediated DESs/DMSO system) has demonstrated significant yields of 5-hydroxymethylfurfural (5-HMF), furfural (FF) and levulinic acid (LevA) of 31.29 %, 28.38 % and 35.65 %, respectively. These favourable results were obtained at the reaction temperature of 140 °C for 40 min. The anticipated catalytic system's activation energy (Ea) was found to be 29.11 kJ/mol. Hence, a practical, inexpensive and sustainable process with the potential of high-value platform chemicals, explicitly for a sustainable strategy in a circular bioeconomy was proposed.

The effect of ingredients commonly used in nasal and inhaled solutions on the secretion of mucus in vitro

Hypersecretion of mucus is associated with impaired mucociliary clearance that can influence the retention of active pharmaceutical ingredients in the airway but is also linked with recurrent airway disease. Therefore, the effect on mucin secretion of a range of ingredients used in solutions delivered to the nose and lung was studied. Mucin secretion from explants of ovine epithelium was quantified using an enzyme-linked lectin assay (ELLA) or sandwich ELLA depending on the compatibility of the ingredients with the assay. Benzalkonium chloride (0.015% w/w), Methocel™ E50 premium LV (1.0% w/w), propylene glycol (1.5% w/w), potassium sorbate + propylene glycol (0.3% w/w + 1.5% w/w) and polysorbate 80 (0.025% w/w), used at common working concentrations, all increased the secretion of mucin from the explants (P < 0.05). Ethylenediamine tetraacetic acid-disodium salt (EDTA) (0.015% w/w), Avicel® RC591 (1.5% w/w), fluticasone furoate (0.0004% w/w, concentration in solution) and dimethyl sulfoxide (DMSO) (0.2% w/w) did not affect mucin secretion. Compounds increasing mucin secretion could alter the rate of mucociliary clearance and the mucus could provide a barrier to drug absorption. This could predispose patients to disease and affect the activity of delivered drugs, decreasing or increasing their clinical efficacy.

Cryoprotectant-dependent control of intracellular ice recrystallization in hepatocytes using small molecule carbohydrate derivatives

To promote the recovery of cells that undergo intracellular ice formation (IIF), it is imperative that the recrystallization of intracellular ice is minimized. Hepatocytes are more prone to IIF than most mammalian cells, and thus we assessed the ability of novel small molecule carbohydrate-based ice recrystallization inhibitors (IRIs) to permeate and function within hepatocytes. HepG2 monolayers were treated with N-(4-chlorophenyl)-d-gluconamide (IRI 1), N-(2-fluorophenyl)-d-gluconamide (IRI 2), or para-methoxyphenyl-β-D-glycoside (IRI 3) and fluorescent cryomicroscopy was used for real time visualization of intracellular ice recrystallization. Both IRI 2 and IRI 3 reduced rates of intracellular recrystallization, whereas IRI 1 did not. IRI 2 and IRI 3, however, demonstrated a marked reduction in efficiency in the presence of the most frequently used permeating cryoprotectants (CPAs): glycerol, propylene glycol (PG), dimethyl sulfoxide (DMSO), and ethylene glycol (EG). Nevertheless, IRI 3 reduced rates of intracellular recrystallization relative to CPA-only controls in the presence of glycerol, PG, and DMSO. Interestingly, IRI preparation in trehalose, a commonly used non-permeating CPA, did not impact the activity of IRI 3. However, trehalose did increase the activity of IRI 1 while decreasing that of IRI 2. While this study suggests that each of these compounds could prove relevant in hepatocyte cryopreservation protocols where IIF would be prominent, CPA-mediated modulation of intracellular IRI activity is apparent and warrants further investigation.

Effects of ectoine on behavioral, physiological and biochemical parameters of Daphnia magna exposed to dimethyl sulfoxide

DMSO is a very common solvent for hydrophobic chemicals that may pose a threat to aquatic organisms. Ectoine (ECT) is a protective amino acid produced by various strains of halophilic bacteria with high potential to alleviate detrimental effects induced by environmental stressors. This amino acid is used in many cosmetics and pharmaceuticals may enter aquatic ecosystems interacting with ions and macromolecules. Little is known on the effects of DMSO and its interaction with ECT on behavioral, physiological and biochemical endpoints of aquatic invertebrates. Therefore, the purpose of the present study was to determine protective effects of DMSO alone and in the combination with ECT on hopping frequency, swimming speed, heart rate, thoracic limb activity, catalase activity and NOx level in an animal model, Daphnia magna subjected to 0.1% and 1% DMSO alone and during combinatorial exposure to ECT (0-25 mg/L) and DMSO for 24 h and 48 h. The results showed that swimming speed, heart rate and thoracic limb activity were inhibited by both 0.1% and 1% DMSO alone however alleviating effects were observed in the combination DMSO + ECT. Thoracic limb activity was higher in the animals exposed to both solutions of DMSO alone, however the parameter was more stimulated at DMSO + ECT. The results suggest that DMSO alone may alter Daphnia behavior and physiological parameters, therefore use of the control group of non-treated animals with DMSO alone would be recommended to avoid data misinterpretation.

Adoptive transfer of DMSO-induced regulatory T cells exhibits a similar preventive effect compared to an in vivo DMSO treatment for chemical-induced experimental encapsulating peritoneal sclerosis in mice

Encapsulating peritoneal sclerosis (EPS) is a severe complication of peritoneal dialysis (PD). This disease leads to intestinal obstruction with or without peritonitis. The imbalance between the populations of Th17 and regulatory T (Treg) cells (higher Th17 cells and lower Treg cells) is part of the pathogenesis of EPS formation. We demonstrated that dimethyl sulfoxide (DMSO) effectively inhibited autoimmune diabetes recurrence in the islet transplantation of NOD mice via the induction of the differentiation of Treg cells. In this study, we investigated the therapeutic potential of DMSO in the inhibition of EPS formation by a mouse model. Under DMSO treatment, the thickening of the parietal and visceral peritoneum was significantly reduced. The populations of CD4, CD8, and IFN-γ-producing CD4 and CD8 T cells were decreased. The populations of IL-4-producing CD4 T lymphocytes, IL-10-producing CD4 T lymphocytes, CD4 CD69 T lymphocytes and Treg lymphocytes were increased. The expression levels of the cytokines IFN-γ, IL-17a, TNF-α and IL-23, in ascites, were significantly decreased following the DMSO treatment. Furthermore, the differentiation of Treg cells was induced by DMSO from naïve CD4 T cells in vitro, and these cells were adoptively transferred into the EPS mice and significantly prevented EPS formation, exhibiting a comparable effect to the in vivo DMSO treatment. We also demonstrated that the differentiation of Treg cells by DMSO occurred via the activation of STAT5 by its epigenetic effect, without altering the PI3K-AKT-mTOR or Raf-ERK pathways. Our results demonstrated, for the first time, that in vivo DMSO treatment suppresses EPS formation in a mouse model. Furthermore, the adoptive transfer of Treg cells that were differentiated from naïve CD4 T cells by an in vitro DMSO treatment exhibited a similar effect to the in vivo DMSO treatment for the prevention of EPS formation.

The role of dimethyl sulfoxide (DMSO) in ex-vivo examination of human skin burn injury treatment

Dimethyl sulfoxide (DMSO) is one of the most versatile solvents in biological science, therefore it is frequently used as a solvent in biological studies and as a vehicle for drug therapy. DMSO readily penetrates, diffuses through biological membranes and ipso facto increases fluidity of liposomal membranes modelling stratum corneum. Thermal injury is associated with the appearance of lipid peroxidation products in the burned skin. The influence of DMSO on protein structure and stability is concentration and temperature dependant. The aim of this study was to assess the impact of DMSO on human burn wounds and examine the interactions between DMSO and skin surface. The real problem in burn treatment is hypoalbuminemia. At the level of the laboratory studies there was an attempt at answering the question of whether the DMSO will modify the standard serum solution. In the case of the incubation of skin fragments in 1%-100% DMSO, the following findings were reported: modification of the serum, appearance of low molecular weight oligomer bands, disappearance of albumin bands or reconstruction of native serum bands during incubation in antioxidant solutions. The result of the modification is also the exposure of FTIR 1603 and 1046cm^-1 bands observed in frozen serum solutions. In the case of modification of the burned skin by DMSO solutions or antioxidants - frequency shifts, an increase in the intensity of amide I band as well as the appearance of the 1601cm^-1 band can be specific biomarkers of the tissue regeneration process. In this study the areas 1780-1580cm^-1 and 1418-1250cm^-1 on the Raman spectra are particularly rich in spectral information.

DMSO: A Mixed-Competitive Inhibitor of Human Acetylcholinesterase

Dimethyl sulfoxide (DMSO) is the most common organic solvent used in biochemical and cellular assays during drug discovery programs. Despite its wide use, the effect of DMSO on several enzyme classes, which are crucial targets of the new therapeutic agents, are still unexplored. Here, we report the detailed biochemical analysis of the effects of DMSO on the human acetylcholine-degrading enzyme, acetylcholinesterase (AChE), the primary target of current Alzheimer's therapeutics. Our analysis showed that DMSO is a considerably potent and highly selective irreversible mixed-competitive inhibitor of human AChE with IC₅₀ values in the lower millimolar range, corresponding to 0.88% to 2.6% DMSO (v/v). Most importantly, 1-4% (v/v) DMSO, the commonly used experimental concentrations, showed ∼37-80% inhibition of human AChE activity. We believe that our results will assist in developing stringent protocols and help in the better interpretation of experimental outcomes during screening and biological evaluation of new drugs.

Detection and confirmation of α-cobratoxin in equine plasma by solid-phase extraction and liquid chromatography coupled to mass spectrometry

α-Cobratoxin (CTX) is a large peptide (71 amino acids) with strong analgesic effect and may be misused in sports such as horse racing. To prevent such misuse, a sensitive method is required for detection and confirmation of the toxin in equine samples. CTX was extracted from equine plasma using an optimized mixed-mode solid-phase extraction (SPE) procedure. Extracted CTX was reduced with dithiothreitol and alkylated with iodoacetamide, and then was digested by trypsin at 56°C for 30min. The digest was analysed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), and tryptic peptides T2 (³CFITPDITSK¹²) and T4 (²⁴TWCDAFCSIR³³) were monitored for detection and confirmation of CTX. The limit of detection (LOD) was 0.05ng/mL for CTX in plasma, and the limit of confirmation (LOC) 0.2ng/mL. Unlike small peptides consisting of the 20 canonical amino acids, CTX was stable in equine plasma at ambient temperature for at least 24h. The developed analytical method was successfully applied to analysis of incurred plasma samples; CTX was detected in plasma collected 15min through 36h post subcutaneous administration of CTX (2.0mg dose) to a research horse, and confirmed 30min through 24h. Additionally, an approach named "reliable targeted SEQUEST search" has been proposed for assessing the specificity of T2 at product ion spectrum level for confirmation of CTX. T2 is uniquely specific for CTX, as evaluated with this approach and BLAST search. Furthermore, the effect of dimethyl sulfoxide (DMSO) as a mobile phase additive on electrospray (ESI) response of T2 and T4, background noise level and signal to noise ratio (S/N) was examined; DMSO increased signal intensity of T2 and T4 by a factor of less than 2. It is the first report that DMSO raised background noise level and did not improve S/N for the peptides, to the authors' knowledge. The developed analytical method may be applicable for analysis of CTX in plasma from other species such as greyhound dogs or even human beings.

The assessment of electrophysiological activity in human-induced pluripotent stem cell-derived cardiomyocytes exposed to dimethyl sulfoxide and ethanol by manual patch clamp and multi-electrode array system

INTRODUCTION

Recently, electrophysiological activity has been effectively measured in human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to predict drug-induced arrhythmia. Dimethyl sulfoxide (DMSO) and ethanol have been used as diluting agents in many experiments. However, the maximum DMSO and ethanol concentrations that can be effectively used in the measurement of electrophysiological parameters in hiPSC-CMs-based patch clamp and multi-electrode array (MEA) have not been fully elucidated.

METHODS

We investigated the effects of varying concentrations of DMSO and ethanol used as diluting agents on several electrophysiological parameters in hiPSC-CMs using patch clamp and MEA.

RESULTS

Both DMSO and ethanol at concentrations>1% in external solution resulted in osmolality >400mOsmol/kg, but pH was not affected by either agent. Neither DMSO nor ethanol led to cell death at the concentrations examined. However, resting membrane potential, action potential amplitude, action potential duration at 90% and 40%, and corrected field potential duration were decreased significantly at 1% ethanol concentration. DMSO at 1% also significantly decreased the sodium spike amplitude. In addition, the waveform of action potential and field potential was recorded as irregular at 3% concentrations of both DMSO and ethanol. Concentrations of up to 0.3% of either agent did not affect osmolality, pH, cell death, or electrophysiological parameters in hiPSC-CMs.

DISCUSSION

Our findings suggest that 0.3% is the maximum concentration at which DMSO or ethanol should be used for dilution purposes in hiPSC-CMs-based patch clamp and MEA.

Evaluation of Serum-Free, Xeno-Free Cryopreservation Solutions for Human Adipose-Derived Mesenchymal Stem Cells

Adipose-derived mesenchymal stem cells (ASCs) have the potential to differentiate into cells of mesodermal origin, such as osteoblasts, adipocytes, myocytes, and chondrocytes, and cryopreservation is currently performed as a routine method for preserving ASCs to safely acquire large numbers of cells. For clinical application of ASCs, serum-free, xeno-free cryopreservation solutions should be used. This study determined the viability and adipo-osteogenic potential of cryopreserved ASCs using four cryopreservation solutions: 10% DMSO, Cell Banker 2 (serum free), Stem Cell Banker (=Cell Banker 3: serum free, xeno free), and TC protector (serum free, xeno free). The viability of the cryopreserved ASCs was over 80% with all cryopreservation solutions. No difference in the adipo-osteogenic potential was found between the cells that did or did not undergo cryopreservation in these cryopreservation solutions. These data suggest that Cell Banker 3 and TC protector are comparable with 10% DMSO and Cell Banker 2 for ASCs, and cryopreserved as well as noncryopreserved ASCs could be applied for regenerative medicine.

The use of dimethyl sulfoxide in contact lens disinfectants is a potential preventative strategy against contracting Acanthamoeba keratitis

Acanthamoeba castellanii is the causative agent of blinding keratitis. Though reported in non-contact lens wearers, it is most frequently associated with improper use of contact lens. For contact lens wearers, amoebae attachment to the lens is a critical first step, followed by amoebae binding to the corneal epithelial cells during extended lens wear. Acanthamoeba attachment to surfaces (biological or inert) and migration is an active process and occurs during the trophozoite stage. Thus retaining amoebae in the cyst stage (dormant form) offers an added preventative measure in impeding parasite traversal from the contact lens onto the cornea. Here, we showed that as low as 3% DMSO, abolished A. castellanii excystation. Based on the findings, it is proposed that DMSO should be included in the contact lens disinfectants as an added preventative strategy against contracting Acanthamoeba keratitis.

Biogenesis of Escherichia coli DMSO Reductase: A Network of Participants for Protein Folding and Complex Enzyme Maturation

Protein folding and structure have been of interest since the dawn of protein chemistry. Following translation from the ribosome, a protein must go through various steps to become a functional member of the cellular society. Every protein has a unique function in the cell and is classified on this basis. Proteins that are involved in cellular respiration are the bioenergetic workhorses of the cell. Bacteria are resilient organisms that can survive in diverse environments by fine tuning these workhorses. One class of proteins that allow survival under anoxic conditions are anaerobic respiratory oxidoreductases, which utilize many different compounds other than oxygen as its final electron acceptor. Dimethyl sulfoxide (DMSO) is one such compound. Respiration using DMSO as a final electron acceptor is performed by DMSO reductase, converting it to dimethyl sulfide in the process. Microbial respiration using DMSO is reviewed in detail by McCrindle et al. (Adv Microb Physiol 50:147-198, 2005). In this chapter, we discuss the biogenesis of DMSO reductase as an example of the participant network for complex iron-sulfur molybdoenzyme maturation pathways.

Cryopreservation of Adipose-Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) have the potential to differentiate into cells of mesodermal origin such as osteoblasts, adipocytes, myocytes, and chondrocytes. They possess an immunosuppressive effect, which makes them a viable cell population for the cell-based therapy of treatment-resistant immune diseases. Adipose-derived mesenchymal stem cells (ASCs) have been demonstrated to have the ability to acquire the properties of subcutaneous adipose tissue particularly easily, and cryopreservation is currently performed as a routine method for preserving ASCs to safely acquire large numbers of cells. However, many studies have reported that cellular activity after freezing and thawing may be affected by the solutions used for cryopreservation. Dimethyl sulfoxide (DMSO) is commonly used as a cryopreservation medium as it diffuses into the cell through the plasma membrane and protects the cells from the damage caused by freezing. As substitutes for DMSO or animal-derived serum, cell banker series, polyvinylpyrrolidone (PVP), sericin and maltose, and methyl cellulose (MC) have been investigated for their clinical applications. It is critical to develop a reliable cell cryopreservation protocol for regenerative medicine using MSCs.

Characterization of odor emission from alternating aerobic and anoxic activated sludge systems using real-time total reduced sulfur analyzer

Anaerobic biodegradation of sulfur-containing compounds always generates volatile sulfur compounds (VSCs) including H2S, methyl mercaptan, and dimethyl sulfide (DMS). VSC emissions from wastewater treatment plants (WWTPs) result in odor complaints from people living nearby. To control odor-causing compounds in WWTPs, it is important to know the odor emission quantity particularly with continuous monitoring. Since modified activated sludge processes always include anaerobic, anoxic and aerobic conditions for nutrient removal, odor emission from these different environmental settings is expected. In this study, continuous monitoring of VSCs from the headspace of an alternating aerobic and anoxic (AAA) activated sludge process via total reduced sulfur (TRS) analyzer was performed. There is clear pattern of the initial TRS peak immediately after the initiation of the aeration in the AAA system and TRS concentration begins to drop through the remaining air-on cycle. On the other hand, during the air-off period, TRS concentrations increase with time. In particular, a clear inflection point in the TRS profile could be observed after complete removal of nitrate during air-off, meaning more VSCs formation. Since the highest odor emission occurs after the initiation of aeration, the future control of exhausted air should only deal with air collected during the initial aeration period (e.g., 30min), a similar concept for the treatment of first flush in combined sewer overflow. In addition, application of a control scheme to initiate aeration immediately after denitrification is completed during air-off should be beneficial in reducing odor emission.