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Collagen prolyl 4-hydroxylases (C-P4H) are α2ß2 tetramers, which catalyze the prolyl 4-hydroxylation of procollagen, allowing for the formation of the stable triple-helical collagen structure in the endoplasmic reticulum. The C-P4H α-subunit provides the N-terminal dimerization domain, the middle peptide-substrate-binding (PSB) domain, and the C-terminal catalytic (CAT) domain, whereas the ß-subunit is identical to the enzyme protein disulfide isomerase (PDI). The structure of the N-terminal part of the α-subunit (N-terminal region and PSB domain) is known, but the structures of the PSB-CAT linker region and the CAT domain as well as its mode of assembly with the ß/PDI subunit, are unknown. Here, we report the crystal structure of the CAT domain of human C-P4H-II complexed with the intact ß/PDI subunit, at 3.8 Å resolution. The CAT domain interacts with the a, b', and a' domains of the ß/PDI subunit, such that the CAT active site is facing bulk solvent. The structure also shows that the C-P4H-II CAT domain has a unique N-terminal extension, consisting of α-helices and a ß-strand, which is the edge strand of its major antiparallel ß-sheet. This extra region of the CAT domain interacts tightly with the ß/PDI subunit, showing that the CAT-PDI interface includes an intersubunit disulfide bridge with the a' domain and tight hydrophobic interactions with the b' domain. Using this new information, the structure of the mature C-P4H-II α2ß2 tetramer is predicted. The model suggests that the CAT active-site properties are modulated by α-helices of the N-terminal dimerization domains of both subunits of the α2-dimer.
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Prolil Hidroxilases , Isomerases de Dissulfetos de Proteínas , Humanos , Domínio Catalítico , Colágeno/metabolismo , Peptídeos/metabolismo , Pró-Colágeno-Prolina Dioxigenase/metabolismo , Prolil Hidroxilases/metabolismo , Isomerases de Dissulfetos de Proteínas/metabolismo , Conformação ProteicaRESUMO
Integrin activation and clustering by talin are early steps of cell adhesion. Membrane-bound talin head domain and kindlin bind to the ß integrin cytoplasmic tail, cooperating to activate the heterodimeric integrin, and the talin head domain induces integrin clustering in the presence of Mn2+ Here we show that kindlin-1 can replace Mn2+ to mediate ß3 integrin clustering induced by the talin head, but not that induced by the F2-F3 fragment of talin. Integrin clustering mediated by kindlin-1 and the talin head was lost upon deletion of the flexible loop within the talin head F1 subdomain. Further mutagenesis identified hydrophobic and acidic motifs in the F1 loop responsible for ß3 integrin clustering. Modeling, computational and cysteine crosslinking studies showed direct and catalytic interactions of the acidic F1 loop motif with the juxtamembrane domains of α- and ß3-integrins, in order to activate the ß3 integrin heterodimer, further detailing the mechanism by which the talin-kindlin complex activates and clusters integrins. Moreover, the F1 loop interaction with the ß3 integrin tail required the newly identified compact FERM fold of the talin head, which positions the F1 loop next to the inner membrane clasp of the talin-bound integrin heterodimer.This article has an associated First Person interview with the first author of the paper.
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Integrina beta3 , Talina , Adesão Celular , Análise por Conglomerados , Integrina beta3/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , Talina/genética , Talina/metabolismoRESUMO
The phosphonium-decorated phenanthro-imidazolyl pyridine ligand, LP+Br, readily reacts with zinc(II) and cadmium(II) bromides to give inorganic-organic zero-dimensional compounds [LP+ZnBr2]2[ZnBr4] (1) and [(LP+)2Cd2Br4][CdBr4] (2), respectively, upon crystallization. These salts are moderately fluorescent in the solid state under ambient conditions (λem = 458 nm, Φem = 0.11 for 1; λem = 460 nm, Φem = 0.13 for 2). Their emission results from spin-allowed electronic transitions localized on the organic component with the negligible effect of [MBr4]2- and MBr2 units. Contrary to ionic species 1 and 2, lead(II) bromide affords a neutral and water-stable complex [(LP+)2Pb3Br8] (3), showing weak room-temperature phosphorescence arising from spin-orbit coupling due to the heavy atom effect. The emission, which is substantially enhanced for the amorphous sample of 3 (λem = 575 nm, Φem = 0.06), is assigned to the intraligand triplet excited state, which is a rare phenomenon among Pb(II) molecular materials.
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INTRODUCTION: Coniferous trees, especially their needles and bark, are a rich source of bioactive compounds. The developing needles of Norway spruce (Picea abies), also known as spruce sprouts, are enriched with vitamin C and other antioxidants, and thus they are used as a dietary supplement and have been traditionally used to treat various inflammatory disorders such as rheumatism and gout. Their chemical composition is only limitedly known, however. OBJECTIVES: The main objective of this work was to have a deeper understanding on the chemical composition of spruce sprouts to assess their full potential in different pharmaceutical, nutraceutical, or technochemical applications. MATERIALS AND METHODS: Ultrahigh-resolution Fourier-transform ion cyclotron (FT-ICR) mass spectrometry, coupled to direct-infusion electrospray ionisation (ESI) or atmospheric pressure photoionisation (APPI) techniques, was used for in-depth compositional analysis of solvent extracts and essential oil of spruce sprouts. RESULTS: A combined use of ESI and APPI techniques offered a great complementary insight into the rich chemistry of different spruce sprout extracts, allowing detection of thousands of chemical constituents with over 200 secondary metabolites tentatively identified. These compounds belonged to different classes such as organic acids, terpenes, flavonoids, stilbenes, sterols, and nitrogen alkaloids. CONCLUSION: Spruce sprouts have a complex metabolite profile that differs considerably from that of the old, developed needles.
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Óleos Voláteis , Picea , Espectrometria de Massas , Picea/química , Picea/metabolismo , Solventes , Terpenos/análiseRESUMO
Caulobacter crescentus xylonolactonase (Cc XylC, EC 3.1.1.68) catalyzes an intramolecular ester bond hydrolysis over a nonenzymatic acid/base catalysis. Cc XylC is a member of the SMP30 protein family, whose members have previously been reported to be active in the presence of bivalent metal ions, such as Ca2+, Zn2+, and Mg2+. By native mass spectrometry, we studied the binding of several bivalent metal ions to Cc XylC and observed that it binds only one of them, namely, the Fe2+ cation, specifically and with a high affinity (Kd = 0.5 µM), pointing out that Cc XylC is a mononuclear iron protein. We propose that bivalent metal cations also promote the reaction nonenzymatically by stabilizing a short-lived bicyclic intermediate on the lactone isomerization reaction. An analysis of the reaction kinetics showed that Cc XylC complexed with Fe2+ can speed up the hydrolysis of d-xylono-1,4-lactone by 100-fold and that of d-glucono-1,5-lactone by 10-fold as compared to the nonenzymatic reaction. To our knowledge, this is the first discovery of a nonheme mononuclear iron-binding enzyme that catalyzes an ester bond hydrolysis reaction.
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Proteínas de Bactérias/química , Hidrolases de Éster Carboxílico/química , Caulobacter crescentus/enzimologia , Proteínas de Bactérias/metabolismo , Hidrolases de Éster Carboxílico/metabolismo , Gluconatos/química , Hidrólise , Ferro/química , Ferro/metabolismo , Cinética , Lactonas/química , Espectrometria de Massas/métodos , Ligação ProteicaRESUMO
Cyanobacteria are important photosynthetic organisms inhabiting a range of dynamic environments. This phylum is distinctive among photosynthetic organisms in containing genes encoding uncharacterized cystathionine ß-synthase (CBS)-chloroplast protein (CP12) fusion proteins. These consist of two domains, each recognized as stand-alone photosynthetic regulators with different functions described in cyanobacteria (CP12) and plants (CP12 and CBSX). Here we show that CBS-CP12 fusion proteins are encoded in distinct gene neighborhoods, several unrelated to photosynthesis. Most frequently, CBS-CP12 genes are in a gene cluster with thioredoxin A (TrxA), which is prevalent in bloom-forming, marine symbiotic, and benthic mat cyanobacteria. Focusing on a CBS-CP12 from Microcystis aeruginosa PCC 7806 encoded in a gene cluster with TrxA, we reveal that the domain fusion led to the formation of a hexameric protein. We show that the CP12 domain is essential for hexamerization and contains an ordered, previously structurally uncharacterized N-terminal region. We provide evidence that CBS-CP12, while combining properties of both regulatory domains, behaves different from CP12 and plant CBSX. It does not form a ternary complex with phosphoribulokinase (PRK) and glyceraldehyde-3-phosphate dehydrogenase. Instead, CBS-CP12 decreases the activity of PRK in an AMP-dependent manner. We propose that the novel domain architecture and oligomeric state of CBS-CP12 expand its regulatory function beyond those of CP12 in cyanobacteria.
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Proteínas de Bactérias/genética , Proteínas de Cloroplastos/genética , Cistationina beta-Sintase/genética , Microcystis/genética , Família Multigênica , Proteínas de Bactérias/metabolismo , Proteínas de Cloroplastos/metabolismo , Cistationina beta-Sintase/metabolismo , Microcystis/metabolismo , Domínios ProteicosRESUMO
This study assessed the pyrolysis liquids obtained by slow pyrolysis of industrial hemp leaves, hurds, and roots. The liquids recovered between a pyrolysis temperature of 275-350 °C, at two condensation temperatures 130 °C and 70 °C, were analyzed. Aqueous and bio-oil pyrolysis liquids were produced and analyzed by proton nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), and atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS). NMR revealed quantitative concentrations of the most abundant compounds in the aqueous fractions and compound groups in the oily fractions. In the aqueous fractions, the concentration range of acetic acid was 50-241 gL-1, methanol 2-30 gL-1, propanoic acid 5-20 gL-1, and 1-hydroxybutan-2-one 2 gL-1. GC-MS was used to compare the compositions of the volatile compounds and APPI FT-ICR MS was utilized to determine the most abundant higher molecular weight compounds. The different obtained pyrolysis liquids (aqueous and oily) had various volatile and nonvolatile compounds such as acetic acid, 2,6-dimethoxyphenol, 2-methoxyphenol, and cannabidiol. This study provides a detailed understanding of the chemical composition of pyrolysis liquids from different parts of the industrial hemp plant and assesses their possible economic potential.
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Cannabis/química , Folhas de Planta/química , Raízes de Plantas/química , Cromatografia Gasosa-Espectrometria de Massas , Espectrometria de Massas/métodos , Espectroscopia de Prótons por Ressonância Magnética/métodos , Pirólise , Espectroscopia de Infravermelho com Transformada de Fourier/métodosRESUMO
The SCP2 (sterol carrier protein 2)-thiolase (type-1) functions in the vertebrate peroxisomal, bile acid synthesis pathway, converting 24-keto-THC-CoA and CoA into choloyl-CoA and propionyl-CoA. This conversion concerns the ß-oxidation chain shortening of the steroid fatty acyl-moiety of 24-keto-THC-CoA. This class of dimeric thiolases has previously been poorly characterized. High-resolution crystal structures of the zebrafish SCP2-thiolase (type-1) now reveal an open catalytic site, shaped by residues of both subunits. The structure of its non-dimerized monomeric form has also been captured in the obtained crystals. Four loops at the dimer interface adopt very different conformations in the monomeric form. These loops also shape the active site and their structural changes explain why a competent active site is not present in the monomeric form. Native mass spectrometry studies confirm that the zebrafish SCP2-thiolase (type-1) as well as its human homolog are weak transient dimers in solution. The crystallographic binding studies reveal the mode of binding of CoA and octanoyl-CoA in the active site, highlighting the conserved geometry of the nucleophilic cysteine, the catalytic acid/base cysteine and the two oxyanion holes. The dimer interface of SCP2-thiolase (type-1) is equally extensive as in other thiolase dimers; however, it is more polar than any of the corresponding interfaces, which correlates with the notion that the enzyme forms a weak transient dimer. The structure comparison of the monomeric and dimeric forms suggests functional relevance of this property. These comparisons provide also insights into the structural rearrangements that occur when the folded inactive monomers assemble into the mature dimer.
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Acil Coenzima A/química , Proteínas de Transporte/química , Modelos Moleculares , Proteínas de Peixe-Zebra/química , Animais , Domínio Catalítico , Humanos , Especificidade por Substrato , Peixe-ZebraRESUMO
Many protein complexes are assembled from a varying number of subunits, which are continuously exchanging with diverse time scales. This structural dynamics is considered to be important for many regulatory and sensory adaptation processes that occur in vivo. We have developed an accurate method for monitoring protein subunit exchange by using native electrospray ionization mass spectrometry (ESI-MS), exemplified here for an extremely stable Rad50 zinc hook (Hk) dimer assembly, Zn(Hk)2. The method has two steps: appropriate protein/peptide mutation and native ESI-MS analysis using a variable-temperature sample inlet. In this work, two Hk mutants were produced, mixed with wild-type Hk, and measured at three different temperatures. A thermokinetic analysis of heterodimer formation allowed us to determine the enthalpy, entropy, and Gibbs free energy of activation for subunit exchange, showing that the reaction is slow and associated with a high enthalpic barrier, consistent with the exceptionally high stability of the Zn(Hk)2 assembly.
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Proteínas de Ligação a DNA/química , Espectrometria de Massas , Subunidades Proteicas/química , Temperatura , Sequência de Aminoácidos , Proteínas de Ligação a DNA/metabolismo , Cinética , Modelos Moleculares , Conformação Proteica , Subunidades Proteicas/metabolismoRESUMO
Catechol oxidases and tyrosinases are coupled binuclear copper enzymes that oxidize various o-diphenolic compounds to corresponding o-quinones. Tyrosinases have an additional monooxygenation ability to hydroxylate monophenol to o-diphenol. It is still not clear what causes the difference in the catalytic activities. We solved a complex structure of Aspergillus oryzae catechol oxidase with resorcinol bound into the active site. Catalytic activity of A.â oryzae catechol oxidase was studied, for the first time, by high-resolution FT-ICR mass spectrometry to shed light on the reaction mechanism. The enzyme was also found to catalyze monooxygenation of small phenolics, which provides a novel perspective for the discussion of differences in the catalytic activity between tyrosinases and catechol oxidases. According to the results, two binding modes for resorcinol are suggested and a reaction mechanism for coupled binuclear copper enzymes is discussed.
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Aspergillus oryzae/enzimologia , Catecol Oxidase , Monofenol Mono-Oxigenase/metabolismo , Sítios de Ligação , Catálise , Domínio Catalítico , Catecol Oxidase/química , Catecol Oxidase/metabolismo , Cobre/química , Cristalografia por Raios X , Modelos Moleculares , Oxirredução , Conformação Proteica , Especificidade por SubstratoRESUMO
Combining the star-shaped alkynyl ligands with low-nuclearity gold-copper triphosphane clusters produces 3D metallocage aggregates, which demonstrate room temperature phosphorescence in solution (max Φem =0.6). Their luminescence mainly originates from cluster-localized metal-to-ligand charge transfer excited state. These supramolecular assemblies can be easily converted into the isostructural gold-silver congeners by the direct exchange of the metal ions. Such modification of the terminal metal cores switches the emission to the intraligand (alkyne) electronic transitions of the triplet manifold, that represents an unusual optical functionality among the metallocycle/metallocage complexes.
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Platinum-based micromotors have shown many exciting applications when functionalized using gold-thiol chemistry. However, thiols are known to bind to the Pt surface, which can lead to serious deactivation of the catalyst. In this paper, it is demonstrated that MnO2 can be used to protect Pt-based micromotors prior to the thiol treatment, thus fully avoiding the catalyst poisoning. This approach will greatly facilitate the use of the functionalized Pt micromotors for which the thiol toxicity has been a limiting factor.
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Manganese oxide (MnO2 ) based micromotors exhibiting a dual effect, that is, catalytic degradation and adsorptive bubble separation, were employed for water remediation. The dual effect of MnO2 microparticles led to a greater than 90 % of decolorization of non-biodegradable organic dyes in just 1â h, without the need for external agitation or bubble generation. These findings suggest high potential of MnO2 micromotors for decontamination of organic pollutants from wastewaters or natural water reserves.
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Substâncias Perigosas/química , Compostos de Manganês/química , Óxidos/química , Poluentes Químicos da Água/química , Catálise , Corantes/química , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/análise , Purificação da ÁguaRESUMO
Coinage metal cyanides efficiently react with a triphosphine. PPh2C6H4-PPh-C6H4PPh2 (P(3)). to give the complexes M(P(3))CN, where M = Cu (1), Ag (2), and Au (3), which can further interact with coordinatively unsaturated metal centers [M(P(3))](+) to give the homobimetallic [(P(3))M-CN-M(P(3))](+)X(-) [M = Cu (4a with X(-) = CF3SO3(-) and 4b with X(-) = BF4(-)), Ag (5)] or heterometallic [(P(3))Au-CN-Ag(P(3))](+) (6) species. Extension of this approach also provided the trinuclear complex [(P(3))Cu-NC-Au-CN-Cu(P(3))](+) (7). Compounds 1-5 were characterized in the solid state by X-ray crystallography. The NMR spectroscopic studies revealed that all of the complexes except 6 retain their structures in solution. The title compounds are luminescent in the solid state, with quantum yields ranging from 8 to 87%. The observed photoemission originates mainly from the metal-to-ligand charge-transfer states according to time-dependent density functional theory computational studies. The crystalline bimetallic Cu complexes 4a/4b demonstrate extremely high sensitivity of the emission intensity to molecular O2 (KSV1 = 639 atm(-1) and LOD = 0.010% for 3 times the signal-to-noise ratio).
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Agrobacterium tumefaciens (At) strain C58 contains an oxidative enzyme pathway that can function on both d-glucuronic and d-galacturonic acid. The corresponding gene coding for At keto-deoxy-d-galactarate (KDG) dehydratase is located in the same gene cluster as those coding for uronate dehydrogenase (At Udh) and galactarolactone cycloisomerase (At Gci) which we have previously characterized. Here, we present the kinetic characterization and crystal structure of At KDG dehydratase, which catalyzes the next step, the decarboxylating hydrolyase reaction of KDG to produce α-ketoglutaric semialdehyde (α-KGSA) and carbon dioxide. The crystal structures of At KDG dehydratase and its complexes with pyruvate and 2-oxoadipic acid, two substrate analogues, were determined to 1.7 Å, 1.5 Å, and 2.1 Å resolution, respectively. Furthermore, mass spectrometry was used to confirm reaction end-products. The results lead us to propose a structure-based mechanism for At KDG dehydratase, suggesting that while the enzyme belongs to the Class I aldolase protein family, it does not follow a typical retro-aldol condensation mechanism.
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Agrobacterium tumefaciens/enzimologia , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Hidroliases/química , Hidroliases/metabolismo , Agrobacterium tumefaciens/genética , Aldeído Liases/química , Aldeído Liases/genética , Aldeído Liases/metabolismo , Proteínas Arqueais/química , Proteínas Arqueais/genética , Proteínas Arqueais/metabolismo , Proteínas de Bactérias/genética , Domínio Catalítico/genética , Cristalografia por Raios X , Hidroliases/genética , Concentração de Íons de Hidrogênio , Cinética , Redes e Vias Metabólicas , Modelos Moleculares , Mutagênese Sítio-Dirigida , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Açúcares Ácidos/química , Açúcares Ácidos/metabolismo , Sulfolobus solfataricus/enzimologia , Sulfolobus solfataricus/genética , Espectrometria de Massas em TandemRESUMO
Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry, coupled with electrospray ionization (ESI) or atmospheric-pressure photoionization (APPI), was employed for chemical fingerprinting of baijiu, a traditional Chinese liquor. Baijiu is the most consumed distilled alcoholic beverage globally, with over 10 billion liters sold annually. It is a white (transparent) spirit that exhibits similarities to dark spirits such as whisky or rum in terms of aroma and mouthfeel. In this study, direct-infusion FT-ICR mass spectrometry was used to analyze 10 commercially available baijiu liquors, enabling the examination of both volatile and nonvolatile constituents without the need for tedious sample extractions or compound derivatizations. The chemical fingerprints obtained by FT-ICR MS revealed substantial compositional diversity among different baijiu liquors, reflecting variations in the raw materials and production methods. The main compounds identified included a variety of acids, esters, aldehydes, lactones, terpenes, and phenolic compounds. The use of ESI and APPI provided complementary compositional information; while ESI demonstrated greater selectivity toward polar, aliphatic sample constituents, APPI also ionized semipolar and nonpolar (aromatic) ones.
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In the development of proteins, aptamers, and molecular imprints for diagnostic purposes, a major goal is to obtain a molecule with both a high binding affinity and specificity for the target ligand. Cushing syndrome or Addison's disease can be diagnosed by cortisol level tests. We have previously characterized and solved the crystal structure of an anti-cortisol (17) Fab fragment having a high affinity to cortisol but also significant cross-reactivity to other glucocorticoids, especially the glucocorticoid drug prednisolone. We used native mass spectrometry (MS) to determine the binding affinities of nine steroid hormones to anti-cortisol (17) Fab, including steroidogenic precursors of cortisol. Based on the results, the number of hydroxyl groups in the structure of a steroid ligand plays a key role in the antigen recognition by the Fab fragment as the ligands with three hydroxyl groups, cortisol and prednisolone, had the highest affinities. The antibody affinity toward steroid hormones often decreases with a decrease in the number of hydroxyl groups in the structure. The presence of the hydroxyl group at position C11 increased the affinity more than did the other hydroxyl groups at positions C17 or C21. The binding affinities obtained by native MS were compared to the values determined by surface plasmon resonance (SPR), and the affinities were found to correlate well between these two techniques. Our study demonstrates that native MS with a large dynamic range and high sensitivity is a versatile tool for ligand binding studies of proteins.
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Hydroxymethylbilane synthase (HMBS), involved in haem biosynthesis, catalyses the head-to-tail coupling of four porphobilinogens (PBGs) via a dipyrromethane (DPM) cofactor. DPM is composed of two PBGs, and a hexapyrrole is built before the tetrapyrrolic 1-hydroxymethylbilane product is released. During this elongation, stable enzyme (E) intermediates are formed from the holoenzyme, with additional PBG substrates (S): ES, ES2 , ES3 and ES4 . Native PAGE and mass spectrometry of the acute intermittent porphyria (AIP)-associated HMBS variant p.Arg167Gln demonstrated an increased amount of ES3 . Kinetic parameters indicated catalytic dysfunction, however, the product release was not entirely prevented. Isolation and crystal structure analysis of the ES3 intermediate (PDB: 8PND) showed that a pentapyrrole was fully retained within the active site, revealing that polypyrrole elongation proceeds within the active site via a third interaction site, intermediate pyrrole site 3 (IPS3). The AIP-associated HMBS variant p.Arg195Cys, located on the opposite side to p.Arg167Gln in the active site, accumulated the ES4 intermediate in the presence of excess PBG, implying that product hydrolysis was obstructed. Arg167 is thus involved in all elongation steps and is a determinant for the rate of enzyme catalysis, whereas Arg195 is important for releasing the product. Moreover, by substituting residues in the vicinity of IPS3, our results indicate that a fully retained hexapyrrole could be hydrolysed in a novel site in proximity of the IPS3.
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Hidroximetilbilano Sintase , Porfiria Aguda Intermitente , Humanos , Hidroximetilbilano Sintase/química , Hidroximetilbilano Sintase/genética , Hidroximetilbilano Sintase/metabolismo , Polímeros , Pirróis , Domínio Catalítico , MutaçãoRESUMO
The ongoing challenge of viral transmission, exemplified by the Covid pandemic and recurrent viral outbreaks, necessitates the exploration of sustainable antiviral solutions. This study investigates the underexplored antiviral potential of wooden surfaces. We evaluated the antiviral efficacy of various wood types, including coniferous and deciduous trees, against enveloped coronaviruses and nonenveloped enteroviruses like coxsackie virus A9. Our findings revealed excellent antiviral activity manifesting already within 10 to 15 min in Scots pine and Norway spruce, particularly against enveloped viruses. In contrast, other hardwoods displayed varied efficacy, with oak showing effectiveness against the enterovirus. This antiviral activity was consistently observed across a spectrum of humidity levels (20 to 90 RH%), while the antiviral efficacy manifested itself more rapidly at 37 °C vs 21 °C. Key to our findings is the chemical composition of these woods. Resin acids and terpenes were prevalent in pine and spruce, correlating with their antiviral performance, while oak's high phenolic content mirrored its efficacy against enterovirus. The pine surface absorbed a higher fraction of the coronavirus in contrast to oak, whereas enteroviruses were not absorbed on those surfaces. Thermal treatment of wood or mixing wood with plastic, such as in wood-plastic composites, strongly compromised the antiviral functionality of wood materials. This study highlights the role of bioactive chemicals in the antiviral action of wood and opens new avenues for employing wood surfaces as a natural and sustainable barrier against viral transmissions.
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Antivirais , Enterovirus , Madeira , Madeira/química , Antivirais/química , Antivirais/farmacologia , Enterovirus/efeitos dos fármacos , Coronavirus/efeitos dos fármacos , Inativação de Vírus/efeitos dos fármacos , Propriedades de Superfície , Quercus/química , Humanos , Pinus/química , Picea/química , Árvores/virologiaRESUMO
Brominated flame retardants (BFRs) are persistent organic pollutants that pose a major threat to the environment. In this study, a direct insertion probe (DIP) coupled with atmospheric pressure chemical ionization (APCI) quadrupole time-of-flight mass spectrometry (QTOF-MS) was used to characterize additives, especially BFRs, from solid polymer samples with minimal sample preparation. A temperature-programmed DIP analysis, from 150 to 450 °C within 10 min, was utilized to achieve temporal separation of analytes based on their boiling or degradation temperatures, thereby facilitating their easier identification within a single run. Studied BFRs showed different behaviors during the analysis: decabromodiphenyl ether and tetrabromobisphenol A were found to be stable within the studied temperature range, while hexabromocyclododecane already started to debrominate. Our study showed that the DIP-APCI-MS method suited well for the direct qualitative identification of BFRs from polymer matrices. Furthermore, by optimizing the sampling procedure with cryogenic grinding, even quantitative analysis could be performed. The DIP measurements also provided important information about the composition of polymer matrices, including the identification of the comonomers present. Overall, DIP-APCI QTOF-MS was found to be an excellent tool for the compositional analysis of plastic samples. Developing rapid and reliable analysis methods can pave the way for more efficient plastic recycling and the safer use of plastic recyclates.