Examination of primary aromatic amines content in polylactic acid straws and migration into food simulants using SERS with LC-MS.

Polylactic acid (PLA) straws hold eco-friendly potential; however, residual diisocyanates used to enhance the mechanical strength can generate carcinogenic primary aromatic amines (PAAs), posing health risks. Herein, we present a rapid, comprehensive strategy to detecting PAAs in 18 brands of food-grade PLA straws and assessing their migration into diverse food simulants. Surface-enhanced Raman spectroscopy was conducted to rapidly screen straws for PAAs. Subsequently, qualitative determination of migrating PAAs into various food simulants (4 % acetic acid, 10 % ethanol, 50 % ethanol) occurred at 70 °C for 2 h using liquid chromatography-mass spectrometry. Three PAAs including 4,4'-methylenedianiline, 2,4'-methylenedianiline, and 2,4-diaminotoluene were detected in all straws. Specifically, 2,4-diaminotoluene in 50 % ethanol exceeded specific migration limit of 2 µg/kg, raising safety concerns. Notably, PAAs migration to 10 % and 50 % ethanol surpassed that to 4 % acetic acid within a short 2-hour period. Moreover, PLA straws underwent varying degrees of shape changes before and after migration. Straws with poly(butylene succinate) resisted deformation compared to those without, indicating enhanced heat resistance, while poly(butyleneadipate-co-terephthalate) improved hydrolysis resistance. Importantly, swelling study unveiled swelling effect wasn't the primary factor contributing to the increased PAAs migration in ethanol food simulant, as there was no significant disparity in swelling degrees across different food simulants. FT-IR and DSC analysis revealed higher PAAs content in 50 % ethanol were due to highly concentrated polar ethanol disrupting hydrogen bonds and van der Waal forces holding PLA molecules together. Overall, minimizing contact between PLA straws and alcoholic foods is crucial to avoid potential safety risks posed by PAAs.

Carbonyl-amine condensation coupled ozonolysis of dipropylamine and styrene: Decay kinetics, reaction mechanism, secondary organic aerosol formation and cytotoxicity.

Oxidation of organic amines (OAs) or aromatic hydrocarbons (AHs) produces carbonyls, which further react with OAs to form carbonyl-amine condensation products, threatening environmental quality and human health. However, there is still a lack of systematic understanding of the carbonyl-amine condensation reaction processes of OAs or between OAs and AHs, and subsequent environmental health impact. This work systematically investigated the carbonyl-amine condensation coupled ozonolysis kinetics, reaction mechanism, secondary organic aerosol (SOA) formation and cytotoxicity from the mixture of dipropylamine (DPA) and styrene (STY) by a combined method of product mass spectrometry identification, particle property analysis and cell exposure evaluation. The results from ozonolysis of DPA and STY mixture revealed that STY inhibited the ozonolysis of DPA to different degrees to accelerate its own decay rate. The barycenter of carbonyl-amine condensation reactions was shifted from inside of DPA to between DPA and STY, which accelerated STY ozonolysis, but slowed down DPA ozonolysis. For the first time, ozonolysis of DPA and STY mixture to complex carbonyl-amine condensation products through the reactions of DPA with its carbonyl products, DPA with STY's carbonyl products and DPA's bond breakage product with STY's carbonyl products was confirmed. These condensation products significantly contributed to the formation and growth of SOA. The SOA containing particulate carbonyl-amine condensation products showed definite cytotoxicity. These findings are helpful to deeply and comprehensively understand the transformation, fate and environmental health effects of mixed organics in atmospheric environment.

Quantitative Spermidine Detection in Cosmetics using an Organic Transistor-based Chemical Sensor.

Spermidine is an essential biomarker related to antiaging. Although the detection of spermidine levels is in high demand in life science fields, easy-to-use analytical tools without sample purification have not yet been fully established. Herein, we propose an organic field-effect transistor-based chemical sensor for quantifying the spermidine concentration in commercial cosmetics. An extended-gate structure was employed for organic field-effect transistor (OFET)-based chemical sensing in aqueous media. A coordination-bond-based sensing system was introduced into the OFET device to visualize the spermidine detection information through changes in the transistor characteristics. The extended-gate-type OFET has shown quantitative responses to spermidine, which indicates sufficient detectability (i. e., the limit of detection for spermidine: 2.3 µM) considering actual concentrations in cosmetics. The applicability of the OFET-based chemical sensor for cosmetic analysis was validated by instrumental analysis using high-performance liquid chromatography. The estimated recovery rates for spermidine in cosmetic ingredient products (108-111 %) suggest the feasibility of cosmetic analysis based on the OFET-based chemical sensor.

Asymmetric organocatalytic synthesis of chiral homoallylic amines.

In recent decades, the chiral allylation of imines emerged as a key methodology in the synthesis of alkaloids and natural products with 4-, 5- and 6-membered cyclic amine motifs. Initially reliant on stoichiometric reagents, synthetic chemists predominantly used N-substituted chiral imines, organometallic chiral reagents and achiral reagents with an equimolar chiral controller. However, recent years have witnessed the rise of asymmetric transition-metal catalysts and, importantly, organocatalytic allylation, reshaping the landscape of modern synthetic chemistry. This review explores the latest developments in the asymmetric allylation of imines, encompassing cutting-edge advances in hydrogen-bond catalysis and non-classical approaches. Furthermore, practical examples showcasing the application of these innovative methodologies in total synthesis are presented.

Formation of acetonitrile (CH3CN) under cold interstellar, tropospheric and combustion mediums.

The knowledge of the formation of gas-phase carcinogenic acetonitrile (CH3CN) is limited in interstellar, troposphere, and combustion mediums; thus, its formation and fate are of great importance for all these gas-phase environments when accessing its toxicity and its wide range of applications. In this work, we propose a mechanism for the formation of CH3CN from the reaction of OH/O2 on ethanimine (CH3CH=NH) using ab initio/Density Functional Theory (DFT) potential energy surface in combination with microcanonical variational transition state theory (µVTST) and Ramsperger-Kassel-Marcus (RRKM)/master equation (ME) simulation to predict the rate constants and branching fraction in the temperature range of 100 K to 1000 K and pressure range of 0.0001 bar to 100 bar. The reaction starts with cis (Z) and trans (E) CH3CH=NH isomer with OH radical followed by spontaneous formation via pre-reactive complex, forming the carbon and nitrogen-centered radicals. The O2 radical then attacks the carbon and nitrogen-centered radicals to form acetonitrile (CH3CN) and HO2 radicals. The results show that N-H and C-H dominate the H-atoms abstraction by OH radicals is similar to its isoelectronic analogous reaction system, i.e., CH3CHO + OH/O2 and CH3CHCH2 + OH/O2 and similar to methanimine (CH2NH) systems. The calculated rate constants for OH-initiated oxidation of CH3CH=NH are in the range of ~ 10-11 cm3 molecule-1 s-1 (at 300 K) and are in very good agreement with previous experimental values of its isoelectronic reaction system. The atmospheric lifetime due to the loss of CH3CHNH by OH radical (10 to 11 h) is in very good agreement with the similar pollutants in the troposphere temperature range between 200 and 320 K. The results indicate that its contribution to global warming is negligible. However, the formation of products such as CH3CN may interact with other atmospheric species, which could lead to the production of potentially hazardous compounds such as cyanogen (N2C2) and hydrogen cyanide (HCN).

Alterations of Ceramides, Acylcarnitines, GlyceroLPLs, and Amines in NSCLC Tissues.

Abnormal lipid metabolism plays an important role in cancer development. In this study, nontargeted lipidomic study on 230 tissue specimens from 79 nonsmall cell lung cancer (NSCLC) patients was conducted using ultraperformance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS). Downregulation of sphingosine and medium-long-chain ceramides and short-medium-chain acylcarnitine, upregulation of long-chain acylcarnitine C20:0, and enhanced histamine methylation were revealed in NSCLC tissues. Compared with paired noncancerous tissues, adenocarcinoma (AC) tissues had significantly decreased levels of sphingosine, medium-long-chain ceramides (Cer d18:1/12:0 and Cer d16:1/14:0, Cer d18:0/16:0, Cer d18:1/16:0, Cer d18:2/16:0, Cer d18:2/18:0), short-medium-chain (C2-C16) acylcarnitines, LPC 20:0 and LPC 22:1, and significantly increased levels of the long-chain acylcarnitine C20:0, LPC 16:0, LPC P-16:0, LPC 20:1, LPC 20:2, glyceroPC, LPE 16:0, and LPE 18:2. In squamous cell carcinoma (SCC) tissues, sphingosine, Cer d18:2/16:0 and Cer d18:2/18:0, and short-medium-chain acylcarnitines had significantly lower levels, while long-chain acylcarnitines (C20:0, and C22:0 or C22:0 M), LPC 20:1, LPC 20:2, and N1,N12-diacetylspermine had significantly higher levels compared to controls. In AC and SCC tissues, the levels of LPG 18:0, LPG 18:1, and LPS 18:1 were significantly decreased, while the levels of ceramide-1-phosphate (C1P) d18:0/3:0 or LPE P-16:0, N1-acetylspermidine, and 1-methylhistamine were significantly increased than controls. Furthermore, an orthogonal partial least-squares-discriminant analysis (OPLS-DA) model based on a 4-lipid panel was established, showing good discrimination ability between cancerous and noncancerous tissues.

Thermally-stable single-site Pd on CeO2 catalyst for selective amination of phenols to aromatic amines without external hydrogen.

Developing a new route to produce aromatic amines as key chemicals from renewable phenols is a benign alternative to current fossil-based routes like nitroaromatic hydrogenation, but is challenging because of the high dissociation energy of the Ar-OH bond and difficulty in controlling side reactions. Herein, an aerosolizing-pyrolysis strategy was developed to prepare high-density single-site cationic Pd species immobilized on CeO2 (Pd1/CeO2) with excellent sintering resistance. The obtained Pd1/CeO2 catalysts achieved remarkable selectivity of important aromatic amines (yield up to 76.2%) in the phenols amination with amines without external hydrogen sources, while Pd nano-catalysts mainly afforded phenyl-ring-saturation products. The excellent catalytic properties of the Pd1/CeO2 are closely related to high-loading Pd single-site catalysts with abundant surface defect sites and suitable acid-base properties. This report provides a sustainable route for producing aromatic amines from renewable feedstocks.

The Influence of Heat Treatment on the Photoactivity of Amine-Modified Titanium Dioxide in the Reduction of Carbon Dioxide.

Modification of titanium dioxide using ethylenediamine (EDA), diethylamine (DEA), and triethylamine (TEA) has been studied. As the reference material, titanium dioxide prepared by the sol-gel method using titanium(IV) isopropoxide as a precursor was applied. The preparation procedure involved heat treatment in the microwave reactor or in the high-temperature furnace. The obtained samples have been characterized in detail. The phase composition was determined through the X-ray diffraction method, and the average crystallite size was calculated based on it. Values for specific surface areas and the total pore volumes were calculated based on the isotherms obtained through the low-temperature nitrogen adsorption method. The bang gap energy was estimated based on Tauc's plots. The influence of the type and content of amine, as well as heat treatment on the photocatalytic activity of modified titanium dioxide in the photocatalytic reduction of carbon dioxide, was determined and discussed. It was clear that, regardless of the amount and content of amine introduced, the higher photoactivity characterized the samples prepared in the microwave reactor. The highest amounts of hydrogen, carbon monoxide, and methane have been achieved using triethylamine-modified titanium dioxide.

Cellulose-based colorimetric/ratiometric fluorescence sensor for visual detecting amines and anti-counterfeiting.

Many amines with high toxicity always cause a serious threat to the ecological environment and human health; thus, their detection is important. Herein, a dual-mode colorimetric and ratiometric fluorescent sensor based on cellulose for detecting amines has been constructed by a new strategy. This sensor is made of a "negative response" indicator (Lum-MDI-CA) and a "positive response" indicator (perylene tetracarboxylic acid, PTCA). Lum-MDI-CA was obtained by attaching luminol onto cellulose chains, which emitted blue fluorescence and was quenched upon contact with amines. A possible mechanism of fluorescence quenching phenomenon is proposed by the intramolecular charge transfer (ICT) of Lum-MDI-CA. Subsequently, by simply mixing Lum-MDI-CA with PTCA, a dual-mode fluorescence sensor was designed for visual detection and classification of amines. When adding ammonia (NH3), morpholine (MOR), benzylamine (BNZ), diethylamine (DEA), and triethylamine (TEA), respectively, the dual-mode sensor showed visible different color changes under both UV light and daylight. In addition, owing to the excellent processibility and formability of cellulose acetate backbone, the prepared sensor can be easily processed into different material forms, including inks, coatings, films, and fibers, which still exhibit excellent fluorescence emission. Such sensors based on cellulose fluorescent materials are of great value in anti-counterfeiting and information encryption.

Metal-Free Aminophosphonation: Eco-friendly Synthesis and Photophysical Properties of Fluorescent 3-(Aminoimidazo[1,2-a]pyridin-2-yl)phosphonates.

We report a novel, metal-free procedure for the direct aminophosphonation of imidazo[1,2-a]pyridines in green solvents under open air conditions. This method is characterized by its mild and sustainable conditions, ease of operation, scalability, and excellent functional group compatibility. The synthesized compounds exhibit promising photophysical properties, including significant Stokes shifts and quantum yields, making them potential candidates for innovative fluorescent probes.

Manipulating the Substituent Sphere of a Bicyclic Silicon(I) Ring Compound Results in Anionic Cubane-Type Clusters and a Tetrahedral Silanide.

The reaction of the bicyclic silicon(I) ring compound Si4{N(SiMe3)Mes}4 1 with strong zwitterionic character and moderate sterical demand of the amido substituents with two equivalents of KC8 was investigated. This resulted in the unexpected abstraction of two amido substituents from 1 and additionally in dimerization to a dianionic Si8 cluster compound 2 with four unsubstituted silicon atoms and two [K([18]crown-6)]+ counter cations. Performing this reaction in the absence of [18]crown-6 results in release of only one amido substituent from 1 and dimerization to a dianionic Si8 cluster compound 3 with only two unsubstituted silicon atoms. This reaction with KC8 was repeated and trapping agents such as SiMe3Cl and tBuCl were added in-situ whereupon the second isolated homocyclic silylene 4 and a monoanionic hydride and tBu substituted Si8 cluster 5 with one unsubstituted silicon atom were isolated. Furthermore, 1 was reacted with KOtBu which resulted in the selective abstraction of one SiMe3 group and formation of the tetrahedral silanide 6 with one imido substituent bridging an edge of the tetrahedron.

Influence of flor yeast starters on volatile and nitrogen compounds during a controlled biological aging.

Fino Sherry wine undergoes biological aging carried out by a velum of flor yeast within a traditional dynamic system known as "criaderas and solera". The complex microbiota of biofilm-forming Saccharomyces cerevisiae strains play a crucial role in shaping the distinctive organoleptic profile of these types of wines. For this reason, the aim of this study is to analyze the changes produced by different flor yeast strains in the volatilome and the aminogram of different wines from the criaderas and solera system during biological aging in the laboratory, simulating a flor yeast velum condition at different stages of the system. Results suggest that each strain metabolizes wine differently, finding that depending on the wine, some strains are better suited for the process than others. In addition, it is found that the content of biogenic amines in Fino Sherry wines, previously attributed to malolactic bacteria, varies according to the yeast strain metabolizing the wine, suggesting that flor yeast could be used to modify biogenic amines content during biological aging. Results indicate that the use of selected flor yeast starters in biological aging may be of interest to modulate some parameters during Fino Sherry wine aging.

Reappraisal of the mechanism of cardiovascular responses to sympathomimetic amines in anaesthetised rats: dual α1-adrenoceptor and trace amine receptor mechanisms.

Established dogma is that sympathomimetic amines, including ß-phenylethylamine (PEA), increase blood pressure by releasing noradrenaline from sympathetic neurons. Recent evidence allowing longer contact with isolated immersed tissues indicates other mechanisms. The present study re-evaluates the mechanism of pressor responses to PEA in anaesthetised rats with longer exposure to infusions. Blood pressure and heart rate were monitored by cannulating a common carotid artery of anaesthetised male Sprague-Dawley rats. Drugs were administered by bolus doses or by 20-min infusions via a cannulated jugular vein. Increases in blood pressure by bolus doses of the α-adrenoceptor agonist, phenylephrine, were converted to depressor responses by prazosin and therefore α-adrenoceptor-mediated. Pressor responses to bolus doses of PEA were reduced. PEA infusions yielded four-phase responses: An initial increase in pressure (phase 1) blocked by prazosin was due to α-adrenoceptor vasoconstriction and a secondary fall in pressure (phase 2) due to vasodilatation by nitric oxide release. A later pressure increase (phase 3), further elevated after infusion stopped (phase 4), was not attenuated by prazosin and therefore non-adrenergic. This study showed for the first time that the sympathomimetic amine, ß-phenylethylamine, increases blood pressure by two mechanisms. The established indirect sympathomimetic mechanism applies to bolus dose administration. However, with prolonged exposure to infusions, an additional slow-onset sustained non-adrenergic blood pressure increase occurs, most likely mediated via trace amine-associated receptors (TAAR-1). This response will dominate with prolonged exposures in clinical practice. These results prompt a re-evaluation of established dogma on the indirect sympathomimetic mechanisms of these amines.

Additive-assisted macroscopic self-assembly and control of the shape of assemblies based on host-guest interaction.

In these decades, considerable attention has focused on supramolecular polymers due to their unique structures and properties. More recently, macroscopic supramolecular polymers have attracted increasing interest from not only biologists but also materials scientists inspired by the sophisticated structures and functions of living organisms. Since the functions of supramolecular polymers are strongly dependent on their shape, control of the shape is an important issue in controlling the functions of supramolecular polymers. However, the control of shape in macroscopic supramolecular assemblies has not yet been sufficiently investigated. Previously, we studied the macroscopic self-assembly behavior of super absorbent polymer (SAP) microparticles modified with ß-cyclodextrin (ßCD) and adamantane (Ad) residues (ßCD(x)-SAP and Ad(y)-SAP microparticles, where x and y are the mol% contents of ßCD and Ad residues, respectively). More elongated assemblies were formed at higher y, indicating that the shape of assemblies can be controlled by varying the interaction strength. The noteworthy is that 1-adamantanamine hydrochloride (AdNH3Cl) assisted the formation of assemblies from ßCD(x)-SAP and Ad(y)-SAP microparticles, indicating that AdNH3Cl acts as a chemical stimulus for macroscopic assemblies of ßCD(x)-SAP and Ad(y)-SAP microparticles. In this study, we have thus studied the assembling behavior of ßCD(x)-SAP microparticles with Ad(y)-SAP microparticles and unmodified SAP microparticles assisted by AdNH3Cl, as well as the shape of the resulting macroscopic assemblies. AdNH3Cl assisted the formation of assemblies from ßCD(16.2)-SAP and Ad(15.1)-SAP microparticles, in which AdNH3Cl crosslinked the SAP microparticles through the formation of inclusion complexes of ßCD residues with the Ad residue and the electrostatic interaction of ammonium and carboxylate residues. Assemblies of ßCD(26.7)-SAP and unmodified SAP microparticles were formed at the concentrations of AdNH3Cl ([AdNH3Cl]0) higher than a certain level (ca. 0.05 mM). The aspect ratio (a/b) of assemblies showed a maximum at [AdNH3Cl]0 ~ 0.10 mM, indicating that the chemical stimulus, i.e., addition of AdNH3Cl, controls the shape of assemblies formed from ßCD(26.7)-SAP and unmodified SAP microparticles. This study suggests that other stimuli, e.g., heat, pH, light, redox, and force, can be utilized to control the shape of macroscopic assemblies based on supramolecular interactions.

Microfiltration Membrane Pore Functionalization with Primary and Quaternary Amines for PFAS Remediation: Capture, Regeneration, and Reuse.

The widespread production and use of multi-fluorinated carbon-based substances for a variety of purposes has contributed to the contamination of the global water supply in recent decades. Conventional wastewater treatment can reduce contaminants to acceptable levels, but the concentrated retentate stream is still a burden to the environment. A selective anion-exchange membrane capable of capture and controlled release could further concentrate necessary contaminants, making their eventual degradation or long-term storage easier. To this end, commercial microfiltration membranes were modified using pore functionalization to incorporate an anion-exchange moiety within the membrane matrix. This functionalization was performed with primary and quaternary amine-containing polymer networks ranging from weak to strong basic residues. Membrane loading ranged from 0.22 to 0.85 mmol/g membrane and 0.97 to 3.4 mmol/g membrane for quaternary and primary functionalization, respectively. Modified membranes exhibited a range of water permeances within approximately 45-131 LMH/bar. The removal of PFASs from aqueous streams was analyzed for both "long-chain" and "short-chain" analytes, perfluorooctanoic acid and perfluorobutyric acid, respectively. Synthesized membranes demonstrated as high as 90% rejection of perfluorooctanoic acid and 50-80% rejection of perfluorobutyric acid after 30% permeate recovery. Regenerated membranes maintained the capture performance for three cycles of continuous operation. The efficiency of capture and reuse can be improved through the consideration of charge density, water flux, and influent contaminant concentration. This process is not limited by the substrate and, thus, is able to be implemented on other platforms. This research advances a versatile membrane platform for environmentally relevant applications that seek to help increase the global availability of safe drinking water.

The relationship between the deterioration of frying oil and the generation of hazards during frying.

Deep-fat frying gives food a desirable color and flavor but inevitably leads to oil deterioration and production of hazards. In this study, the simultaneous generation of multiple hazards under different frying conditions was investigated, the deterioration of frying oil was evaluated, and finally, their correlation was analyzed. The results showed that as the temperature of frying chicken wings increased from 150 to 190 °C, the levels of acrylamide (AA), heterocyclic amines (HCAs), and polycyclic aromatic hydrocarbons (PAHs) in the oil also increased proportionally. At 190 °C, the fried potato oil contained the highest AA content of 2.60 mg·kg-1, while the content of HCAs and PAHs was the highest in fried chicken wings oil, with values of 5.06 µg·kg-1 and 5.18 µg·kg-1, respectively. 5-Hydroxymethylfurfural was detected only in fried potato oil. Oil quality deteriorated gradually with increasing frying temperature and heating time, as indicated by increased acid value, carbonyl value, and levels of total polar compounds. Overall, the results indicated hazards were positively correlated with oil deterioration, suggesting that oil deterioration contributed to the generation of hazards. This work links hazards and oil deterioration, which is crucial for improving the quality and safety of fried foods, while reducing negative environmental impacts, and achieving clean production.

Inhibitory action of antimicrobial peptides against the formation of carcinogenic and mutagenic heterocyclic amines in meat.

Thermal processing of meat leads to the development of Maillard's reaction intermediates, and carcinogenic toxicants. For the first time, the effectiveness of three (HX-12A, HX-12B and HX-12C) antimicrobial peptides (AMPs) against the formation of heterocyclic amines (HAs) in chemical and meat model systems. The results showed that AMPs especially 12A and 12C have strong metal chelation potential (48 and 40% at 1 mg/ml) and antioxidant activity (35 and 25% at 1 mg/ml), respectively, which were endorsed by their secondary structure (FTIR analysis) in terms of high ß-sheets (1628 cm-1 and 1672 cm-1) in those AMPs. UPLC-MS analysis revealed that 12A and 12C were the most capable AMPs in MeIQx and PhIP-producing chemical models, respectively, whereas 12B promoted the HAs formation even higher than control. In particular, 12C AMP significantly (P < 0.05) decreased the most abundant carcinogenic HAs (PhIP) up to 90% at 9 mg/100 g of fresh meat, whereas 12A inhibited up to 80% of mutagenic HAs at same level compared to control and 12B. Low Field Nuclear Magnetic Resonance (LF-NMR) test showed that inhibitory effect of 12A and 12C was mediated by means of retaining water (lower T22 and T23 relaxation time) inside the macromolecules. This favorable effect was also evidenced by significantly enhanced tryptophan fluorescent intensity. Finally, based on correlation and principle component analysis, the mechanism of action has been proposed. These outcomes recommend that 12A and 12C are potential AMPs for the attenuation of HAs in thermally processed meat-based products.

Synthesis, Characterization, and Biological Evaluation of N-Methyl Derivatives of Norbelladine.

Norbelladine derivatives have garnered attention in recent years due to their diverse biological activities and pivotal role in the biosynthetic pathway of Amaryllidaceae alkaloids. This study reports the synthesis and biological evaluation of four O,N-methylated derivatives of norbelladine. These derivatives were synthesized through a three-step process: forming imine intermediates from benzaldehydes with tyramine, hydrogenating them to secondary amines, and N-methylating these amines. The products were purified and characterized by 1H and 13C NMR spectroscopy. Their biological activities were assessed by evaluating their ability to inhibit Alzheimer's disease-related enzymes acetylcholinesterase and butyrylcholinesterase. Additionally, the cytotoxic activity of the novel derivatives was tested against cancer cell lines derived from hepatocarcinoma (Huh7), adenocarcinoma (HCT-8), and acute myeloid leukemia (THP-1) cells, and their antiviral properties against a human coronavirus (HCoV-OC43), a flavivirus (dengue virus), and a lentivirus (pseudotyped HIV-1). Docking analysis was performed to understand the impact of the N-methylation on their pharmacological relevance. The results indicate that while N-methylation does not significantly affect antiviral activity, it enhances butyrylcholinesterase inhibition for N-methylnorbelladine and 4'-O,N-dimethylnorbelladine. Overall, this work enhances our understanding of norbelladine derivatives, provides new tools for Alzheimer's disease research, and lays the groundwork for future pharmaceutical developments.

Biochemical and Structural Characterization of a Novel Psychrophilic Laccase (Multicopper Oxidase) Discovered from Oenococcus oeni 229 (ENOLAB 4002).

Recently, prokaryotic laccases from lactic acid bacteria (LAB), which can degrade biogenic amines, were discovered. A laccase enzyme has been cloned from Oenococcus oeni, a very important LAB in winemaking, and it has been expressed in Escherichia coli. This enzyme has similar characteristics to those previously isolated from LAB as the ability to oxidize canonical substrates such as 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,6-dimethoxyphenol (2,6-DMP), and potassium ferrocyanide K4[Fe(CN6)], and non-conventional substrates as biogenic amines. However, it presents some distinctiveness, the most characteristic being its psychrophilic behaviour, not seen before among these enzymes. Psychrophilic enzymes capable of efficient catalysis at low temperatures are of great interest due to their potential applications in various biotechnological processes. In this study, we report the discovery and characterization of a new psychrophilic laccase, a multicopper oxidase (MCO), from the bacterium Oenococcus oeni. The psychrophilic laccase gene, designated as LcOe 229, was identified through the genomic analysis of O. oeni, a Gram-positive bacterium commonly found in wine fermentation. The gene was successfully cloned and heterologously expressed in Escherichia coli, and the recombinant enzyme was purified to homogeneity. Biochemical characterization of the psychrophilic laccase revealed its optimal activity at low temperatures, with a peak at 10 °C. To our knowledge, this is the lowest optimum temperature described so far for laccases. Furthermore, the psychrophilic laccase demonstrated remarkable stability and activity at low pH (optimum pH 2.5 for ABTS), suggesting its potential for diverse biotechnological applications. The kinetic properties of LcOe 229 were determined, revealing a high catalytic efficiency (kcat/Km) for several substrates at low temperatures. This exceptional cold adaptation of LcOe 229 indicates its potential as a biocatalyst in cold environments or applications requiring low-temperature processes. The crystal structure of the psychrophilic laccase was determined using X-ray crystallography demonstrating structural features similar to other LAB laccases, such as an extended N-terminal and an extended C-terminal end, with the latter containing a disulphide bond. Also, the structure shows two Met residues at the entrance of the T1Cu site, common in LAB laccases, which we suggest could be involved in substrate binding, thus expanding the substrate-binding pocket for laccases. A structural comparison of LcOe 229 with Antarctic laccases has not revealed specific features assigned to cold-active laccases versus mesophilic. Thus, further investigation of this psychrophilic laccase and its engineering could lead to enhanced cold-active enzymes with improved properties for future biotechnological applications. Overall, the discovery of this novel psychrophilic laccase from O. oeni expands our understanding of cold-adapted enzymes and presents new opportunities for their industrial applications in cold environments.

Contrasting alterations in brain chemistry in a crustacean intermediate host of two acanthocephalan parasites.

The dynamic properties of neural systems throughout life can be hijacked by so-called manipulative parasites. This study investigated changes in the brain chemistry of the amphipod Gammarus fossarum in response to infection with two trophically-transmitted helminth parasites known to induce distinct behavioral alterations: the bird acanthocephalan Polymorphus minutus and the fish acanthocephalan Pomphorhynchus tereticollis. We quantified brain antioxidant capacity as a common marker of homeostasis and neuroprotection, and brain total protein, on 72 pools of six brains. We analyzed the concentration of serotonin (5HT), dopamine (DA) and tyramine in 52 pools of six brains, by using ultrafast high performance liquid chromatography with electrochemical detection (UHPLC-ECD). Brain total protein concentration scaled hypo-allometrically to dry body weight, and was increased in infected gammarids compared to uninfected ones. The brain of gammarids infected with P. minutus had significantly lower total antioxidant capacity relative to total proteins. Infection with P. tereticollis impacted DA level compared to uninfected ones, and in opposite direction between spring and summer. Brain 5HT level was higher in summer compared to spring independently of infection status, and was decreased by infection after correcting for brain total protein concentration estimated from dry whole-body weight. The potential implication of 5HT/DA balance in parasite manipulation, as a major modulator of the reward-punishment axis, is discussed. Taken together, these findings highlight the need to consider both brain homeostatic and/or structural changes (antioxidant and total protein content) together with neurotransmission balance and flexibility, in studies investigating the impact of parasites on brain and behavior.