Optimization Strategies for Mass Spectrometry-Based Untargeted Metabolomics Analysis of Small Polar Molecules in Human Plasma.

The untargeted approach to mass spectrometry-based metabolomics has a wide potential to investigate health and disease states, identify new biomarkers for diseases, and elucidate metabolic pathways. All this holds great promise for many applications in biological and chemical research. However, the complexity of instrumental parameters on advanced hybrid mass spectrometers can make the optimization of the analytical method immensely challenging. Here, we report a strategy to optimize the selected settings of a hydrophilic interaction liquid chromatography-tandem mass spectrometry method for untargeted metabolomics studies of human plasma, as a sample matrix. Specifically, we evaluated the effects of the reconstitution solvent in the sample preparation procedure, the injection volume employed, and different mass spectrometry-related operating parameters including mass range, the number of data-dependent fragmentation scans, collision energy mode, duration of dynamic exclusion time, and mass resolution settings on the metabolomics data quality and output. This study highlights key instrumental variables influencing the detection of metabolites along with suggested settings for the IQ-X tribrid system and proposes a new methodological framework to ensure increased metabolome coverage.

Occurrence and fate of contaminants of emerging concern and their transformation products after uptake by pak choi (Brassica rapa subsp. chinensis).

Recovery and reuse of nutrients is a major challenge in agriculture. A new process contributing to a circular economy is the anaerobic digestion of food waste, which is a sustainable way of recycling nutrients as the digestate can be used as fertiliser in agriculture and horticulture. However, the digestate may be polluted with contaminants of emerging concern (CECs) that can be circulated back into the food chain, posing a risk to the environment and human health. In this work, the nutrient solution was spiked with 18 selected CECs frequently detected in food waste biogas facilities, and subsequent uptake and fate of these CECs were evaluated in pak choi grown in two different nutrient solutions (mineral and organic). All spiked compounds except two (propylparaben, fenbendazole) were taken up by pak choi plants, with perfluorobutanoic acid (PFBA) and sertraline displaying the highest concentrations (270 and 190 µg/kg fresh weight, respectively). There were no statistically significant differences in uptake between mineral and organic nutrient solutions. Uptake of per- and polyfluoroalkyl substances (PFAS) was negatively correlated with perfluorocarbon chain length and dependent on the functional group (r = -0.73). Sixteen transformation products (TPs) were tentatively identified using suspect screening, most of which were Phase II or even Phase III metabolites. Six of these TPs were identified for the first time in plant metabolism and their metabolic pathways were considered.

A preliminary evaluation of oxidative stress in patients with gastric cancer before chemotherapy.

Introduction: Due to an imbalanced redox status, cancer cells generate intrinsically higher levels of reactive oxygen species (ROS) compared to normal cells. Targeting ROS is an important therapeutic strategy for cancer as exemplified by cancer drugs, which induce ROS-dependent synergistic cytotoxicity in gastric cancer cells. The present study was designed to assess the level of selected oxidative stress biomarkers in blood plasma derived from gastric cancer patients. Material and methods: The study assessed the oxidative/nitrative biomarkers in blood plasma isolated from 51 gastric (adenocarcinoma) cancer patients, compared to a control group of 32 healthy volunteers. Oxidative stress was evaluated using a panel of biomarkers such as plasma protein thiol groups and 3-nitrotyrosine levels as well as indicators of plasma lipid peroxidation, i.e. lipid hydroperoxides (LOOH) and thiobarbituric acid-reactive substances (TBARS). Additionally, the total antioxidant capacity of blood plasma (non-enzymatic capacity of blood plasma, NEAC) was also estimated. Results: Our results showed that patients with gastric cancer had significantly different levels of thiol groups (lower, p < 0.001) and 3-nitrotyrosine (higher, p < 0.0001), LOOH (higher, p < 0.05), TBARS (higher, p < 0.05), NEAC (lower, p < 0.0001), compared to the control group. Conclusions: The present study indicates considerable oxidative/nitrative stress in gastric cancer patients. Our pilot study shows that not a single marker, but a biomarker panel, may be a more reliable representation of oxidative stress in patients with gastric cancer.

Uptake of perfluoroalkyl substances, pharmaceuticals, and parabens by oyster mushrooms (Pleurotus ostreatus) and exposure risk in human consumption.

Organic micropollutants (MPs) pose potential threats to environmental ecosystems and human health. This study investigated uptake of perfluoroalkyl substances (PFASs), pharmaceuticals, and paraben by edible oyster mushrooms (Pleurotus ostreatus), cultivated on spiked growth substrate. Concentrations of pharmaceuticals and paraben in substrate showed a decreasing trend over a 20-day harvesting period, whereas PFAS concentrations were variable over the harvesting period. However, only propylparaben, clarithromycin, and PFASs were detected in fruiting bodies of oyster mushroom. Uptake of PFASs by oyster mushroom fruit bodies was negatively correlated with perfluorocarbon chain length. An impact of MPs on fungal colonization was observed, with decreased respiration in treatments with the highest concentration of MPs, but production of fruiting bodies was not affected by exposure level. The potential human risk from ingestion of MPs was evaluated for oyster mushrooms exposed to the highest concentration of MPs in substrate, based on acceptable daily intake (ADI).

Evaluation of selected balance indices on the stabilometric platform in children after mild head trauma.

INTRODUCTION: The aim of the study was to investigate the occurrence of balance disorders in children after mild head trauma. MATERIAL AND METHODS: Ninety patients after mild head trauma, aged 7-18 years, were examined on a stabilometric platform 48 h and 12 weeks after injury. The results were compared with 50 healthy children. Seven selected parameters of the stabilogram were measured and analyzed. RESULTS: Children hospitalized after head trauma represented 3.78% of all surgical admissions and 6.6% of all patients after head trauma reporting to the emergency department. The values of all parameters in the entire study group 48 h after injury were significantly higher than 12 weeks later (p < 0.03), when they decreased to the level of the values in the controls. An inverse relationship between the value of each parameter and the child's age, both in the study group 48 h after injury (p < 0.014) and in the controls (p < 0.008), was found. The values of all parameters in children of the study group aged 11-15 years 48 h after the injury were significantly higher than 12 weeks later (p < 0.05), and significantly higher than in the controls (p < 0.05). The best indicators describing disorders and normalization of body balance control processes were the total path length of center of pressure (SP-EO), the average center of pressure deflection (MA-EO) and the average center of pressure sagittal deflection (MAAP-EO). CONCLUSIONS: Minor head trauma clearly, though temporarily, disturbed body postural control, especially affecting children aged 11-15. However, all examined patients 3 months after injury controlled the body balance, like their healthy peers.

Polycistronic Expression System for Pichia pastoris Composed of Chitino- and Chitosanolytic Enzymes.

Chitin is one of the most abundant biopolymers. Due to its recalcitrant nature and insolubility in accessible solvents, it is often considered waste and not a bioresource. The products of chitin modification such as chitosan and chitooligosaccharides are highly sought, but their preparation is a challenging process, typically performed with thermochemical methods that lack specificities and generate hazardous waste. Enzymatic treatment is a promising alternative to these methods, but the preparation of multiple biocatalysts is costly. In this manuscript, we biochemically characterised chitin deacetylases of Mucor circinelloides IBT-83 and utilised one of them for the construction of the first eukaryotic, polycistronic expression system employing self-processing 2A sequences. The three chitin-processing enzymes; chitin deacetylase of M. circinelloides IBT-83, chitinase from Thermomyces lanuginosus, and chitosanase from Aspergillus fumigatus were expressed under the control of the same promoter in methylotrophic yeast Pichia pastoris and characterised for their synergistic action towards their respective substrates.

Transformation of Transient Overvoltages by Inductive Voltage Transformers.

Overvoltage transients occur after any type of switching activity in a power network, such as breaker operation, fault occurrence/clearance and rapid load change. This distortion of voltage is transformed to the secondary circuit of a voltage transformer. The maximum values of such impulses may many times exceed the rated value of its secondary voltage. This can lead to malfunction of measuring or protection devices connected to the secondary circuit of a voltage transformer and even their damage. The paper presents the application of determined values of ratio error at harmonics of the inductive voltage of the transformer to predict the value of transformed slow-front transient overvoltage to their secondary circuits. This will help to prevent malfunction of measuring or protection devices connected to the secondary side of the voltage transformer and increase their safety of operation. The inductive voltage transformer equivalent circuit for transformation of higher frequency components of distorted voltage must be extended with internal capacitances of windings. This is caused by the fact that the resonance phenomenon of the slow-front transient overvoltage results from leakage inductance and capacitance of primary winding, not from the magnetic core. Therefore, this behaviour is independent from the value of the applied voltage.

Wideband Self-Calibration Method of Inductive CTs and Verification of Determined Values of Current and Phase Errors at Harmonics for Transformation of Distorted Current.

Self-calibration of a designed wideband inductive current transformer (CT) was carried out in the ampere-turns condition. This method does not require a reference transducer. The values of current and phase errors at the harmonics of frequencies from 100 Hz to 5 kHz were determined for the distorted primary current of the rated main frequency equal to 50 Hz. These results were verified based on the comparison of values measured between two CTs and calculated as the difference between values obtained from their calibration. Moreover, from vectorial diagrams drawn for transformation of the higher harmonics, the source of the change in the values of current and phase errors with frequency is explained. Furthermore, the method for calculation of the values of the corresponding harmonics of the current associated with the active power losses in the core and the magnetization current is presented.

Enzymatic Modifications of Chitin, Chitosan, and Chitooligosaccharides.

Chitin and its N-deacetylated derivative chitosan are two biological polymers that have found numerous applications in recent years, but their further deployment suffers from limitations in obtaining a defined structure of the polymers using traditional conversion methods. The disadvantages of the currently used industrial methods of chitosan manufacturing and the increasing demand for a broad range of novel chitosan oligosaccharides (COS) with a fully defined architecture increase interest in chitin and chitosan-modifying enzymes. Enzymes such as chitinases, chitosanases, chitin deacetylases, and recently discovered lytic polysaccharide monooxygenases had attracted considerable interest in recent years. These proteins are already useful tools toward the biotechnological transformation of chitin into chitosan and chitooligosaccharides, especially when a controlled non-degradative and well-defined process is required. This review describes traditional and novel enzymatic methods of modification of chitin and its derivatives. Recent advances in chitin processing, discovery of increasing number of new, well-characterized enzymes and development of genetic engineering methods result in rapid expansion of the field. Enzymatic modification of chitin and chitosan may soon become competitive to conventional conversion methods.

Accelerated CO2 Hydration with Thermostable Sulfurihydrogenibium azorense Carbonic Anhydrase-Chitin Binding Domain Fusion Protein Immobilised on Chitin Support.

Carbonic anhydrases (CAs) represent a group of enzymes that catalyse important reactions of carbon dioxide hydration and dehydration, a reaction crucial to many biological processes and environmental biotechnology. In this study we successfully constructed a thermostable fusion enzyme composed of the Sulfurihydrogenibium azorense carbonic anhydrase (Saz_CA), the fastest CA discovered to date, and the chitin binding domain (ChBD) of chitinase from Bacillus circulans. Introduction of ChBD to the Saz_CA had no major impact on the effect of ions or inhibitors on the enzymatic activity. The fusion protein exhibited no negative effects up to 60 °C, whilst the fusion partner appears to protect the enzyme from negative effects of magnesium. The prepared biocatalyst appears to be thermally activated at 60 °C and could be partially purified with heat treatment. Immobilisation attempts on different kinds of chitin-based support results have shown that the fusion enzyme preferentially binds to a cheap, untreated chitin with a large crystallinity index over more processed forms of chitin. It suggests significant potential economic benefits for large-scale deployment of immobilised CA technologies such as CO2 utilisation or mineralisation.

Thermosynechococcus as a thermophilic photosynthetic microbial cell factory for CO2 utilisation.

Thermophilic unicellular cyanobacterium Thermosynechococcus elongatus PKUAC-SCTE542, has been developed as a thermophilic photosynthetic microbial cell factory for CO2 utilisation. The strain exhibits its highest growth rate around 55 °C, can withstand up to 15% CO2, and up to 0.5 M concentration of sodium bicarbonate. The strain is also capable of resisting a 200 ppm concentration of NO and SO2 in simulated flue gasses, and these compounds have a positive effect on its growth. Whole genome sequencing of the strain revealed the presence of numerous forms of active transport of nutrients and additional chaperones acting as the predominant mechanism of strain adaptation to high temperatures. Based on the sequenced genome, two neutral gene insertion sites have been identified and engineered using modular vectors. Site-specific knock-ins and knock-outs have been performed using the spectinomycin resistance gene and proved functional, enabling future application of the strain to produce biofuels and biochemicals from waste CO2.

ArcD1 and ArcD2 Arginine/Ornithine Exchangers Encoded in the Arginine Deiminase Pathway Gene Cluster of Lactococcus lactis.

UNLABELLED: The arginine deiminase (ADI) pathway gene cluster in Lactococcus lactis contains two copies of a gene encoding an l-arginine/l-ornithine exchanger, the arcD1 and arcD2 genes. The physiological function of ArcD1 and ArcD2 was studied by deleting the two genes. Deletion of arcD1 resulted in loss of the growth advantage observed in the presence of high l-arginine in different growth media. Uptake of l-arginine and l-ornithine by resting cells was reduced to the low level observed for an ArcD1/ArcD2 double deletion mutant. Deletion of the arcD2 gene did not affect the growth enhancement, and uptake activities were slightly reduced. Nevertheless, recombinant expression of ArcD2 in the ArcD1/ArcD2 double mutant did recover the growth advantage. Kinetic characterization of ArcD1 and ArcD2 showed high affinities for both l-arginine and l-ornithine (Km in the micromolar range). A difference between the two transporters was the significantly lower affinity of ArcD2 for the cationic amino acids l-ornithine, l-lysine, and l-histidine. In contrast, the affinity of ArcD2 was higher for the neutral amino acid l-alanine. Moreover, ArcD2 efficiently translocated l-alanine, while ArcD1 did not. Both transporters revealed affinities in the mM range for agmatine, cadaverine, histamine, and putrescine. These amines bind but are not translocated. It is concluded that ArcD1 is the main l-arginine/l-ornithine exchanger in the ADI pathway and that ArcD2 is not functionally expressed in the media used. ArcD2 is proposed to function together with the arcT gene that encodes a putative transaminase and is found adjacent to the arcD2 gene. IMPORTANCE: The arginine deiminase (ADI) pathway gene cluster in Lactococcus lactis contains two copies of a gene encoding an l-arginine/l-ornithine exchanger, the arcD1 and arcD2 genes. The physiological function of ArcD1 and ArcD2 was studied by deleting the two genes. It is concluded that ArcD1 is the main l-arginine/l-ornithine exchanger in the ADI pathway. ArcD2 is proposed to function as a l-arginine/l-alanine exchanger in a pathway together with the arcT gene, which is found adjacent to the arcD2 gene in the ADI gene cluster.

Symptoms of depression in elderly patients with osteoarticular diseases undergoing hospital rehabilitation.

BACKGROUND: To evaluate the impact of hospital rehabilitation on depression among patients with osteo articular diseases. MATERIAL AND METHODS: An ad hoc questionnaire designed by the authors were the Beck scale and Laitinen scale administered to 50 hospitalized patients with osteoarticular diseases before and after rehabilitation. RESULTS: Symptoms of depression were found in 16 of the 50 patients (32%) on admission to the hospital compared to 8 (16%) after completing rehabilitation (Chi 2 = 4.08, p = 0.0433). The differences in the Beck scale for each of the respondents before and after physiotherapy were statistically significant (p <0.0001). We found a correlation between the occurrence of depression, and the presence of co-morbidities before and after rehabilitation (r = 0.29, r = 0.34). Before (r = 0.36, p = 0.0094) and after rehabilitation (r = 0.64, p <0.0001), symptoms of depression correlated with pain severity. 49 patients (98%), including all 16 with depression, complained of pain. Rehabilitation produced a reduction in pain frequency (p <0.0001), intensity (p <0.0001), medi cation use (p <0.0001) and movement limitation (p = 0.0004). CONCLUSIONS: 1. Patient age, osteoarticular diseases and comorbidities correlated positively with symptoms of depression. 2. Hospital-based rehabilitation of patients with osteoarticular diseases had a significant impact on reducing the incidence and severity of pain and reducing the consumption of analgesics. 3. Hospital rehabilitation helps eliminate or reduce the severity of symptoms of depression and markedly improves patients' daily functioning.

Potential of nano-ZnS as electrocatalyst.

ZnS is a versatile wide-gap semiconductor that shows remarkable chemical stability against oxidation and hydrolysis. These properties are retained when the particle size steps down to 10 nm and below, and thus ZnS nanoparticles are interesting entities for optical and catalytic functions, where they might be exposed to quite aggressive environments. Moreover, ZnS may be doped by a host of elements, so that the electrical and optical properties can be tuned over an extended range. Neither Zn nor S are in short supply, and ZnS as compound or in view of the constituting elements is not toxic. Therefore, functional materials based on ZnS will be ideal for "green chemistry" applications, since they are suited also for large scale manufacture and will pose no additional problems when released into the environment. The article describes first results for ZnS-nanoparticles acting as electrocatalysts, a field that has not been covered so far by ZnS-derived materials. The catalytic action is evaluated for the decomposition of ethanol, a potentially abundant fuel for mobile electricity generation, since it can be fabricated by fermentation from a broad range of organic materials.

1-Methyl-2-(4-methyl-phen-yl)-4-morpholinopyridazine-3,6(1H,2H)-dione.

The structure analysis of the title compound, C(16)H(19)N(3)O(3), has been undertaken in order to facilitate the inter-pretation of (1)H and (13)C NMR data and to determine the position of the morpholine residue in this nucleophilic substitution product. The main result is that the morpholine group, with a chair conformation, is connected at the 4-position of the pyridazine ring. The benzene and pyridazine rings make a dihedral angle of 62.17 (5)°. Mol-ecules are linked into a two-dimensional network by non-classical C-H⋯O hydrogen bonds, in which O atoms serve as double or triple acceptors.

Dynamics of tear fluid components transportation through contact lenses.

The interference optical method has been applied to monitor the transportation of Na(+) and Cl(-) in solution through new and used contact lenses. The phenomenon of passive transportation (simple diffusion), induced by differences in osmotic pressure on both sides of the contact lenses has been discussed. Permeability coefficient of contact lenses of different optical power: -2.75 D and -3.75 D has been calculated.