Low Molecular Weight Compounds Research Articles

High content of low molecular weight organics does not always affect pharmaceutical adsorption on activated carbon: The case of acetate, propionate and ethanol in source-separated urine

Adsorption on activated carbon is a common process to remove pharmaceuticals in wastewater treatment. Activated carbon adsorption is usually applied to wastewater with a low content of biological degradable organics, i.e. after biological treatment. Especially low molecular weight (LMW) compounds are known to compete with pharmaceuticals for adsorption sites. The goal of this study was to test the hypothesis that biological treatment is necessary for efficient pharmaceutical removal. Source-separated urine after anaerobic storage (anaerobically stored urine) and after aerobic biological removal of organics without nitrification (organics-depleted urine) were used in this study. In anaerobically stored urine 60% of the organic compounds were LMW organics, of which about 40% were acetate and propionate. 74% of the DOC and 100% of acetate and propionate were removed during aerobic biological treatment. To investigate the effect of the organic compounds on pharmaceutical removal, sorption experiments with 19 spiked pharmaceuticals and one artificial sweetener were conducted with powdered activated carbon. Ethanol, another LMW organic, was included in the study, as it is regularly used for pharmaceutical spiking thereby strongly increasing the DOC content. The experiments showed that the adsorption of the pharmaceuticals and the sweetener were hardly affected by the easily biodegradable LMW organics or ethanol. Therefore, it was concluded that biological pre-treatment is not necessary for efficient pharmaceutical adsorption. Since acetate, propionate and ethanol contribute substantially to the DOC content but do not absorb UV light, the latter is recommended as indicator for pharmaceutical removal in solutions with high contents of biodegradable LMW organics.

The Effect of Organic Matter from Sewage Sludge as an Interfacial Layer on the Surface of Nano-Al and Fluoride.

Due to its high reactivity, the nano aluminum particle (n-Al) has attracted more attention in energetic materials but is easily oxidized during processing. In order to realize sewage sludge (SS) resource and n-Al coating, the organic matter was extracted from SS, using the deep eutectic solvent method due to its strong dissolving capacity, and then the organic matter was pretreated by ball milling, which was used as an interfacial layer between n-Al and fluoride. It was found that organic matter was successfully extracted from SS. The main organic matter is proteins. The ball milling method can effectively destroy the secondary structure of proteins to release more active functional groups. During the pretreatment, the Maillard reaction broke the proteins structure to form more active low molecular weight compounds. It was confirmed that n-Al can be coated by PBSP under mild conditions to form a uniform core-shell structure. PFOA can effectively coat the n-Al@PBSP to form n-Al@PBSP/PFOA, which can enhance the combustion of n-Al. The gas phase flame temperature can notably improve to 2892 K. The reaction mechanism between n-Al and coating was analyzed. The results could help SS treatment and provide new insights for n-Al coating and SS-based organic matter recovery and utilization.

Aspects of the study on some aromatic species of the genus Agastache Gronov

The study has been focused on the field of introduction, conservation and use of aromatic and medicinal plants, which represent inexhaustible sources of raw materials for the pharmaceutical, cosmetic and food industries. The article describes the results of the evaluation of the prospects for the introduction of 4 species of the genus Agastache Gronov: Agastache foeniculum ( Pursh) Kuntze, Agastache rugosa (Fisch & C. A Mey.) O. Kuntze, Agastache urticifolia (Benth.) Kuntze, Agastache nepetoides L., species that have not been studied in much detail, but of high therapeutic value. The studies focused on the bio-ecological and phytochemical research on the plants, in order to highlight the biomorphological peculiarities, the essential oil content and the possibility of using them in various branches of the national economy. Far from being an exhausted source of remedies, natural products continue to provide low molecular weight compounds with important biological properties that can be used for pharmaceutical purposes.

Oxygen consumption and formation of recalcitrant organic carbon from the decomposition of free-floating macrophyte leachates.

Aquatic macrophytes contain high levels of hydrosoluble compounds. These compounds disproportionately support microbial breakdown and affect biological oxygen demand in eutrophic waters. In this study, we investigated the fate of leachates from free-floating macrophytes (Pistia stratiotes and Eichhornia crassipes) usually present in eutrophic tropical lacustrine environments. After extraction, the leachates were fractioned into high and low molecular weight compounds and incubated under aerobic conditions, in the dark and at 20.0 ± 1.3°C. The concentrations of dissolved oxygen and the total, dissolved, and particulate organic carbon (TOC, DOC, and POC) were determined during 60days. The selected leachates supported the detritus trophic chain of the Barra Bonita Reservoir. High rates of carbon transfer were measured, which were ascribed to the temperature selected (20°C), nutrient availability, and labile fractions of the leachates. Decomposition occurred mainly through catabolic pathways (mineralization), with the formation of POC (immobilization) being only minor. In the early stages of P. stratiotes and E. crassipes decomposition, the mineralization of leachates (mainly the low molecular weight) led to declines in dissolved oxygen. Owing to the low rates of mass loss, the recalcitrant fractions of these leachates should constitute the main forms of organic carbon exported from the reservoir.

A tandem of GC‐MS and electroanalysis for a rapid chemical profiling of bacterial extracellular matrix

AbstractHerein an assay toward a rapid and reliable profiling of extracellular matrix of Escherichia coli (E. coli) utilizing a tandem of GC‐MS as a tool for definition of the exact chemical nature of low molecular weight compounds and cyclic voltammetry for their high throughput detection is presented.Briefly, during a set of investigations the formation of glycerol in the extracellular matrix (ECM) of E. coli at physiological relevant conditions of cells was revealed. Based on the obtained knowledge, the electrochemical protocol allowing both qualitative and quantitative analyses of glycerol in E. coli ECMs at palladium ink‐modified screen printed electrodes with precision values (RSD) <10 % and recovery rates ranged from 98 % to 102 % was proposed.The provided protocol for a rapid electrochemical profiling of the bacterial ECMs can readily be used as a guideline for the controlled electroanalysis of target electroactive signaling analytes in complex biological samples.

Application of Alcohol-Salt Aqueous Biphasic System for the Recovery of Ectoine

Ectoine is an osmoregulatory compound synthesized by halophiles which has attracted attention in the biotechnology, pharmaceuticals, and cosmetics industries due to its stabilizing and protective properties. Conventional methods for ectoine recovery are complex, costly, and often result in low yields. Therefore, there is a growing interest in exploring simple and cost-effective strategies for ectoine recovery. The aqueous biphasic system (ABS) has been employed for the recovery and purification of numerous biocompounds, but the study of low-molecular weight compounds partitioning in ABS remains limited. This study aimed to investigate the feasibility of alcohol–salt ABS for ectoine recovery from Halomonas salina DSM5928T cells. The influences of types and compositions of phase-forming components, crude load concentration, pH, and adjuvants on ectoine recovery were evaluated. Results revealed that ectoine favoured partitioning into the salt-rich bottom phase of alcohol–salt ABS owing to its inherent hydrophilic characteristic. ABS consisting of 16% (w/w) 1-propanol, 20% (w/w) sulphate at pH 6.0, 30% (w/w) crude load, and 1% (w/w) sodium chloride resulted in a partition coefficient (KE) of 9.61 ± 0.05 and a yield (YB) of 97.50% ± 0.21. A purity (PE) of 86.73% was achieved with the 1-propanol-sulphate ABS. Alcohol–salt ABS proved to be an effective approach for ectoine recovery, meeting the raising market demand for industrial applications.

Exoproteomic Study and Transcriptional Responses of Laccase and Ligninolytic Peroxidase Genes of White-Rot Fungus Trametes hirsuta LE-BIN 072 Grown in the Presence of Monolignol-Related Phenolic Compounds.

Being an abundant renewable source of aromatic compounds, lignin is an important component of future bio-based economy. Currently, biotechnological processing of lignin through low molecular weight compounds is one of the conceptually promising ways for its valorization. To obtain lignin fragments suitable for further inclusion into microbial metabolism, it is proposed to use a ligninolytic system of white-rot fungi, which mainly comprises laccases and peroxidases. However, laccase and peroxidase genes are almost always represented by many non-allelic copies that form multigene families within the genome of white-rot fungi, and the contributions of exact family members to the overall process of lignin degradation has not yet been determined. In this article, the response of the Trametes hirsuta LE-BIN 072 ligninolytic system to the presence of various monolignol-related phenolic compounds (veratryl alcohol, p-coumaric acid, vanillic acid, and syringic acid) in culture media was monitored at the level of gene transcription and protein secretion. By showing which isozymes contribute to the overall functioning of the ligninolytic system of the T. hirsuta LE-BIN 072, the data obtained in this study will greatly contribute to the possible application of this fungus and its ligninolytic enzymes in lignin depolymerization processes.

Use of carbon-13 NMR to identify known natural products by querying a nuclear magnetic resonance database-An assessment.

The quick identification of known organic low molecular weight compounds, also known as structural dereplication, is a highly important task in the chemical profiling of natural resource extracts. To that end, a method that relies on carbon-13 nuclear magnetic resonance (NMR) spectroscopy, elaborated in earlier works of the author's research group, requires the availability of a dedicated database that establishes relationships between chemical structures, biological and chemical taxonomy, and spectroscopy. The construction of such a database, called acd_lotus, was reported earlier, and its usefulness was illustrated by only three examples. This article presents the results of structure searches carried out starting from 58 carbon-13 NMR data sets recorded on compounds selected in the metabolomics section of the biological magnetic resonance bank (BMRB). Two compound retrieval methods were employed. The first one involves searching in the acd_lotus database using commercial software. The second one operates through the freely accessible web interface of the nmrshiftdb2 database, which includes the compounds present in acd_lotus and many others. The two structural dereplication methods have proved to be efficient and can be used together in a complementary way.

Regulation on copper-tolerance in Citrus sinensis seedlings by boron addition: Insights from root exudates, related metabolism, and gene expression

Boron (B) can alleviate Citrus copper (Cu)-toxicity. However, the underlying mechanism by which B mitigates Cu-toxicity is unclear. ‘Xuegan’ (Citrus sinensis) seedlings were exposed to 0.5 (control) or 350 (Cu-toxicity) µM Cu and 2.5 or 25 µM B for 24 weeks. Thereafter, we investigated the secretion of low molecular weight compounds [LMWCs; citrate, malate, total soluble sugars (TSS), total phenolics (TP), and total free amino acids (TFAA)] by excised roots and their concentrations in roots and leaves, as well as related enzyme gene expression and activities in roots and leaves. Cu-stress stimulated root release of malate and TFAA, which might contribute to citrus Cu-tolerance. However, B-mediated-mitigation of Cu-stress could not be explained in this way, since B addition failed to further stimulate malate and TFAA secretion. Indeed, B addition decreased Cu-stimulated-secretion of malate. Further analysis suggested that Cu-induced-exudation of malate and TFAA was not regulated by their levels in roots. By contrast, B addition increased malate, citrate, and TFAA concentrations in Cu-toxic roots. Cu-toxicity increased TP concentration in 25 μM B-treated leaves, but not in 2.5 μM B-treated leaves. Our findings suggested that the internal detoxification of Cu by LMWCs played a role in B-mediated-alleviation of Cu-toxicity.

Modeling the Biocatalytic Method of Lipid Extraction Using Artificial Neural Networks

The paper presents the data on lipid fraction extraction from the raw fat of hibernating hunting animals. The processing of valuable raw materials must be maximized. For this purpose, various methods of rendering are used. As a result of temperature exposure, the protein part of raw fat undergoes significant changes. The protein denatures under the influence of temperature, and the dross formed during the rendering process absorbs and retains up to 30% of the fat. The authors propose using proteolytic enzyme preparations for a more complete extraction of fats, as the enzymes will hydrolyze the protein into compounds of lower molecular weight both before and during the rendering process. The experiment proved that the biocatalytic method allows achieving a fat yield of more than 95%. The best result can be obtained if the rendering is carried out at optimal parameters, which can be defined using a mathematical model. Mathematical modeling was carried out using an artificial neural network. During the study, a fully connected neural network was designed; it had eight hidden layers with 64 neurons in each, and its accuracy was measured by mean relative error, which amounted to 5.16%. With the help of the network, the optimal values of applied concentration, temperature and duration of rendering, at which a fat yield of more than 98% is achieved, were determined for each enzyme preparation. After that, the obtained values were confirmed experimentally. Thus, the study showed the efficiency of using artificial neural networks for modeling the biocatalytic method of lipid extraction.

Recent advances in lignins: fundamentals and applications

Lignin, one of the most abundant biopolymers on Earth, is a constant object of numerous fundamental and applied studies. Lignin processing is a challenging task of biorefining. Recent publications mainly concern various directions of valorization of technical lignins, as well as applications of lignin in medicine and pharmacology, 3D printing, synthesis of carbon fibres and biofuels. In the field of fundamental research, studies on lignin biosynthesis are of special attention. The review is devoted to the latest advances in the chemistry of lignin. The currently available data on the structure and biosynthesis of lignin are discussed. The trends in lignin valorization, such as pyrolysis and carbonation, production of composites, copolymers and nanoparticles, synthesis of practically valuable low-molecular-weight substances, production of hydro- and aerogels, <i>etc</i>., are analyzed in detail. It is noted that at present, the practical application of lignin is developing in two directions: valorization of technical lignins <i>per se</i>, without prior depolymerization, and valorization <i>via</i> low molecular weight compounds, mainly monomers, formed through lignin degradation by various methods.<br> The bibliography includes 130 references.

A comparative study for evaluating the binding affinity of MARAS-selected aptamer and a patented aptamer towards aflatoxin B1 by electrochemical impedimetric aptasensing

Magnetic-assisted rapid aptamer selection (MARAS) is a technique that uses magnetic nanoparticles to efficiently separate aptamer-target complexes under an alternating magnetic field, thereby reducing the time and number of selection rounds required. This study investigated the applicability of MARAS in selecting aptamers against a small molecule, aflatoxin B1 (AFB1). Among the six MARAS-selected aptamers, DNA 1 demonstrated the highest binding affinity. Its Kd value, further estimated from aptasensing data, was 43.7 nM, which is comparable to the Kd value of the patented aptamer (55.6 nM). The DNA 1-immobilized aptasensor exhibited good repeatability (RSD < 7 %, N = 3), linearity (R2 = 0.9613 from 1 to 100 nM), and a calculated LOD of 0.42 nM. Specificity testing indicated that interferences from ochratoxin A, aflatoxin B2, aflatoxin G1, and aflatoxin G2 were all below 7 %. The developed aptasensor was also applied to detect AFB1 content in the peanut sample matrix, achieving a good recovery rate ranging from 94.3 % to 112.2 %. Overall, this study confirms the potential of MARAS as a promising technique for identifying aptamers with strong binding affinities towards low molecular weight compounds such as AFB1. Additionally, the DNA 1-immobilized aptasensor provided a simple, accurate, and cost-effective alternative for AFB1 monitoring.

Position matters in ester thiolysis by cysteine-containing peptides in micelles and vesicles

HypothesisThe interaction of peptides with nanoaggregates is an active research topic. Cysteine (Cys)-containing peptides open opportunities for developing low molecular weight compounds with interesting properties and potential applications. Knowledge of the relationship between the position of the Cys in the peptides and the aggregate interface is essential. ExperimentsWe synthesized a series of Cys-containing peptides having a variable number of glycines (Gly) as spacers between the N-palmitoyl chain at their N-terminal portion and Cys at their carboxy-terminal. The apparent pKa of the Cys-thiol group of each peptide was measured in micelles of CTAC (hexadecyltrimethylammonium chloride) and vesicles of DHDAC (dihexadecyldimethylammonium chloride). No clear correlation existed between the pKa’s and the number of Gly in the peptides. However, the rate of p-nitro-phenyl-octanoate (NPO) thiolysis by the peptides in micelles and vesicles decreased regularly with peptide length. Molecular Dynamics (MD) analysis of the peptides in CTAC micelles was carried out. FindingspKa determinations and rate dependence of the peptides in a thiolysis reaction and MD analysis strongly suggested that the higher rates observed with shorter peptides can be attributed to an increased probability of Cys being located below the micellar surface, where the carbonyl reaction center of NPO resides.

Cyanotoxins, biosynthetic gene clusters, and factors modulating cyanotoxin biosynthesis.

Cyanobacterial harmful algal blooms (CHABs) are a global environmental concern that encompasses public health issues, water availability, and water quality owing to the production of various secondary metabolites (SMs), including cyanotoxins in freshwater, brackish water, and marine ecosystems. The frequency, extent, magnitude, and duration of CHABs are increasing globally. Cyanobacterial species traits and changing environmental conditions, including anthropogenic pressure, eutrophication, and global climate change, together allow cyanobacteria to thrive. The cyanotoxins include a diverse range of low molecular weight compounds with varying biochemical properties and modes of action. With the application of modern molecular biology techniques, many important aspects of cyanobacteria are being elucidated, including aspects of their diversity, gene-environment interactions, and genes that express cyanotoxins. The toxicological, environmental, and economic impacts of CHABs strongly advocate the need for continuing, extensive efforts to monitor cyanobacterial growth and to understand the mechanisms regulating species composition and cyanotoxin biosynthesis. In this review, we critically examined the genomic organization of some cyanobacterial species that lead to the production of cyanotoxins and their characteristic properties discovered to date.

Infection Meets Inflammation: N6-Methyladenosine, an Internal Messenger RNA Modification as a Tool for Pharmacological Regulation of Host-Pathogen Interactions.

The significance of internal mRNA modifications for the modulation of transcript stability, for regulation of nuclear export and translation efficiency, and their role in suppressing innate immunity is well documented. Over the years, the molecular complexes involved in the dynamic regulation of the most prevalent modifications have been characterized-we have a growing understanding of how each modification is set and erased, where it is placed, and in response to what cues. Remarkably, internal mRNA modifications, such as methylation, are emerging as an additional layer of regulation of immune cell homeostasis, differentiation, and function. A fascinating recent development is the investigation into the internal modifications of host/pathogen RNA, specifically N6-methyladenosine (m6A), its abundance and distribution during infection, and its role in disease pathogenesis and in shaping host immune responses. Low molecular weight compounds that target RNA-modifying enzymes have shown promising results in vitro and in animal models of different cancers and are expanding the tool-box in immuno-oncology. Excitingly, such modulators of host mRNA methyltransferase or demethylase activity hold profound implications for the development of new broad-spectrum therapeutic agents for infectious diseases as well. This review describes the newly uncovered role of internal mRNA modification in infection and in shaping the function of the immune system in response to invading pathogens. We will also discuss its potential as a therapeutic target and identify pitfalls that need to be overcome if it is to be effectively leveraged against infectious agents.

Experimental and computational study of polystyrene sulfonate breakdown by a Fenton reaction

Experimental studies and ab initio quantum chemistry calculations were combined to investigate the process by which a Fenton reaction breaks down polystyrene sulfonate. The experimental results show that both molecular weight reduction and loss of aromaticity occur nearly simultaneously, a finding that is supported by the calculations. The results show that more than half of the material is broken down to low molecular weight compounds (< 500 g/mol) with two molar equivalents of H2O2 per styrene monomer. The calculations provide insights into the reaction pathways and indicate that at least two hydroxyl radicals are required to cleave backbone CC bonds or to eliminate aromaticity. The calculations also show that, of the aromatic carbons, hydroxyl radical is most likely to add to the carbon bonded to sulfur. This finding explains the loss of hydrogen sulfite anion early in the process and also the efficient reduction of Fe(III) to Fe(II) through semiquinone formation. Taken together the experimental and computational results indicate that the reaction is very efficient and that very little H2O2 is lost to unproductive reactions. This high efficiency is attributed to the close association of Fe atoms with the sulfonate group such that hydroxyl radicals are generated near the polymer chains.

Custom-modified oligolactide-cyclodextrin derivatives for electrospun drug formulations

Custom-synthesized cyclodextrin-oligolactide derivatives (CDLA) were used to produce electrospun nanofibers. The modified cyclodextrins were obtained through solution ring-opening oligomerization initiated by α-, β-, or γ-cyclodextrin in the presence of 4-dimethylaminopyridine. Following the NMR spectroscopy and mass spectrometry structural characterization, the CDLA derivatives are described as low molecular weight compounds having the lactate monomer units placed on the smaller rim of cyclodextrins as multiple short chains. The electrospinning (ESP) of the α-, β- and γ-CDLA homologous series was optimized for the use of high-concentration water/ethanol feed solutions. Scanning electron microscopy was employed for the morphology investigation of the nanofibrous webs, while the dynamic vapor sorption revealed the hygroscopicity changes induced through the ESP process. Further, the applicative potential was investigated by preparing α-, β- and γ-CDLA/curcumin nanofibrous webs. FTIR and NMR spectroscopy characterization, and thermogravimetric analysis were used to describe the particularities of curcumin association with CDLA in ESP process. The preservation of the curcumin antioxidative potential upon the ESP processing was tested, showing that β- and γ-CDLA/curcumin nanofibrous webs are better suited for curcumin formulations.

NUDT6 and NUDT9, two mitochondrial members of the NUDIX family, have distinct hydrolysis activities

The 22 members of the NUDIX (NUcleoside DIphosphate linked to another moiety, X) hydrolase superfamily can hydrolyze a variety of phosphorylated molecules including (d)NTPs and their oxidized forms, nucleotide sugars, capped mRNAs and dinucleotide coenzymes such as NADH and FADH. Beside this broad range of enzymatic substrates, the NUDIX proteins can also be found in different cellular compartments, mainly in the nucleus and in the cytosol, but also in the peroxisome and in the mitochondria. Here we studied two members of the family, NUDT6 and NUDT9. We showed that NUDT6 is expressed in human cells and localizes exclusively to mitochondria and we confirmed that NUDT9 has a mitochondrial localization. To elucidate their potential role within this organelle, we investigated the functional consequences at the mitochondrial level of NUDT6- and NUDT9-deficiency and found that the depletion of either of the two proteins results in an increased activity of the respiratory chain and an alteration of the mitochondrial respiratory chain complexes expression. We demonstrated that NUDT6 and NUDT9 have distinct substrate specificity in vitro, which is dependent on the cofactor used. They can both hydrolyze a large range of low molecular weight compounds such as NAD+(H), FAD and ADPR, but NUDT6 is mainly active towards NADH, while NUDT9 displays a higher activity towards ADPR.

Bioactive compound profile of propolis product from Beekeeping (Meliponiculture) in Turi Yogyakarta Indonesia

Medicinal bio-products have been used all over the world for the treatment and prevention of various ailments, particularly in developing countries where infectious diseases are endemic and modern health facilities and services are inadequate. There is growing evidence in the correlation of the bio-chemical constituents found in medicinal bio-products with their pharmacological activities. One source of natural bioproduct medicine is propolis from the stingless bee. The objective of this research was to analyze the composition of bioactive compunds found in the methanolic extract of raw propolis from the stingless bee farmed in the meliponiculture practice in Turi, Yogyakarta, Indonesia. The raw propolis sample was extracted with methanol by using the soxhlet extractor and the obtained crude methanolic extract was then analyzed using the gas chromatography-mass spectrometry (GC-MS) method. The qualitative analyses of the methanolic crude extract using the GC-MS showed that the profile of the propolis’ chromatogram has different types of high and low molecular weight compounds consisting of 26 bioactive compounds which can be categorized in 3 (three) different groups: terpenoids, phenolic, and steroids. Most of the bioactive compounds are found to be biologically important. Futher research is still needed to further analyze the presence of other various bioactive compounds and to confirm and isolate their individual bio-chemical constituents for treatment of various ailment and the bioprospecting of potential antimicrobial drugs.

Concentration of polycyclic aromatic hydrocarbons (PAHs) and histological changes in Anomalocardia brasiliana and Crassostrea rhizophorae from Pernambuco, Brazil after the 2019 oil spill

The present study aimed to analyze the concentrations of polycyclic aromatic hydrocarbons (PAHs) in populations of the shellfish Anomalocardia brasiliana and oysters Crassostrea rhizophorae three years after the 2019 oil spill, as well as evaluate histopathological changes on the gill tissues of the bivalves. Individuals of both species were sampled at points along the northern and southern coast of Pernambuco, Brazil. The permanence of oil residues was confirmed, evidenced by the total concentration of PAHs in the shellfish from the northern coast, which was roughly four times higher than the southern one. Among the PAHs analyzed, the low molecular weight compounds naphthalene and anthracene were the main contributors to the total concentration. Histological changes in the gills of the bivalves, were more severe in the specimens sampled on the north coast indicating alterations in the bivalve's health, mainly on the state's northern coast.