RESUMO
Most eukaryotic cells express small regulatory RNAs. The purpose of one class, the somatic endogenous siRNAs (endo-siRNAs), remains unclear. Here, we show that the endo-siRNA pathway promotes odor adaptation in C. elegans AWC olfactory neurons. In adaptation, the nuclear Argonaute NRDE-3, which acts in AWC, is loaded with siRNAs targeting odr-1, a gene whose downregulation is required for adaptation. Concomitant with increased odr-1 siRNA in AWC, we observe increased binding of the HP1 homolog HPL-2 at the odr-1 locus in AWC and reduced odr-1 mRNA in adapted animals. Phosphorylation of HPL-2, an in vitro substrate of the EGL-4 kinase that promotes adaption, is necessary and sufficient for behavioral adaptation. Thus, environmental stimulation amplifies an endo-siRNA negative feedback loop to dynamically repress cognate gene expression and shape behavior. This class of siRNA may act broadly as a rheostat allowing prolonged stimulation to dampen gene expression and promote cellular memory formation. PAPERFLICK:
Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiologia , Regulação para Baixo , Guanilato Ciclase/genética , Interferência de RNA , Células Receptoras Sensoriais/metabolismo , Adaptação Fisiológica , Animais , Butanonas/química , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Odorantes , Fosforilação , RNA de Helmintos/metabolismo , RNA Interferente Pequeno/metabolismo , Proteínas de Ligação a RNA/metabolismoRESUMO
Reactive carbonyl species (RCS), which are abundant in the environment and are produced in vivo under stress, covalently bind to nucleophilic residues such as Cys in proteins. Disruption of protein function by RCS exposure is predicted to play a role in the development of various diseases such as cancer and metabolic disorders, but most studies on RCS have been limited to simple cytotoxicity validation, leaving their target proteins and resulting physiological changes unknown. In this study, we focused on methyl vinyl ketone (MVK), which is one of the main RCS found in cigarette smoke and exhaust gas. We found that MVK suppressed PI3K-Akt signaling, which regulates processes involved in cellular homeostasis, including cell proliferation, autophagy, and glucose metabolism. Interestingly, MVK inhibits the interaction between the epidermal growth factor receptor and PI3K. Cys656 in the SH2 domain of the PI3K p85 subunit, which is the covalently binding site of MVK, is important for this interaction. Suppression of PI3K-Akt signaling by MVK reversed epidermal growth factor-induced negative regulation of autophagy and attenuated glucose uptake. Furthermore, we analyzed the effects of the 23 RCS compounds with structures similar to MVK and showed that their analogs also suppressed PI3K-Akt signaling in a manner that correlated with their similarities to MVK. Our study demonstrates the mechanism of MVK and its analogs in suppressing PI3K-Akt signaling and modulating physiological functions, providing a model for future studies analyzing environmental reactive species.
Assuntos
Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Butanonas/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Humanos , Linhagem Celular Tumoral , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologiaRESUMO
Transcription initiates the formation of single-stranded DNA (ssDNA) regions within the genome, delineating transcription bubbles, a highly dynamic genomic process. Kethoxal-assisted single-stranded DNA sequencing (KAS-seq) utilizing N3-kethoxal has emerged as a potent tool for mapping specific guanine positions in ssDNA on a genome-wide scale. However, the original KAS-seq method required the costly Accel-NGS Methyl-seq DNA library kit. This study introduces an optimized iteration of the KAS-seq technique, referred to as adapter-tagged KAS-seq (atKAS-seq), incorporating an adapter tagging strategy. This modification involves integrating sequencing adapters via complementary strand synthesis using random N9 tagging. Additionally, by harnessing the potential of ascorbic acid (ASC), recognized for inducing global epigenetic changes, we employed the atKAS-seq methodology to elucidate critical pathways influenced by short-term, high-dose ASC treatment. Our findings underscore that atKAS-seq enables rapid and precise analyses of transcription dynamics and enhancer activities concurrently. This method offers a streamlined, cost-efficient, and low-input approach, affirming its utility in probing intricate genomic regulatory mechanisms.
Assuntos
Ácido Ascórbico , DNA de Cadeia Simples , Ácido Ascórbico/farmacologia , Butanonas , Sequências Reguladoras de Ácido Nucleico , Sequenciamento de Nucleotídeos em Larga Escala/métodosRESUMO
Many people convicted for drunken driving suffer from an alcohol use disorder and some traffic offenders consume denatured alcohol for intoxication purposes. Venous blood samples from people arrested for driving under the influence of alcohol were analyzed in triplicate by headspace gas chromatography (HS-GC) using three different stationary phases. The gas chromatograms from this analysis sometimes showed peaks with retention times corresponding to acetone, ethyl methyl ketone (2-butanone), 2-propanol, and 2-butanol in addition to ethanol and the internal standard (1-propanol). Further investigations showed that these drink-driving suspects had consumed an industrial alcohol (T-Red) for intoxication purposes, which contained > 90% w/v ethanol, acetone (~ 2% w/v), 2-butanone (~ 5% w/v) as well as Bitrex to impart a bitter taste. In n = 75 blood samples from drinkers of T-Red, median concentrations of ethanol, acetone, 2-butanone, 2-propanol and 2-butanol were 2050 mg/L (2.05 g/L), 97 mg/L, 48 mg/L, 26 mg/L and 20 mg/L, respectively. In a separate GC analysis, 2,3-butanediol (median concentration 87 mg/L) was identified in blood samples containing 2-butanone. When the redox state of the liver is shifted to a more reduced potential (excess NADH), which occurs during metabolism of ethanol, this favors the reduction of low molecular ketones into secondary alcohols via the alcohol dehydrogenase (ADH) pathway. Routine toxicological analysis of blood samples from apprehended drivers gave the opportunity to study metabolism of acetone and 2-butanone without having to administer these substances to human volunteers.
Assuntos
Acetona , Butanonas , Etanol , Oxirredução , Humanos , Etanol/sangue , Cetonas/sangue , Cromatografia Gasosa , Masculino , Adulto , Feminino , Intoxicação Alcoólica , Condução de Veículo , 2-Propanol , Concentração Alcoólica no Sangue , Consumo de Bebidas Alcoólicas , Álcoois , Pessoa de Meia-IdadeRESUMO
Cisplatin (CDDP) is a widely used chemotherapeutic agent that has remarkable antineoplastic effects. However, CDDP can cause severe acute kidney injury (AKI), which limits its clinical application. Agrimol B is the main active ingredient found in Agrimonia pilosa Ledeb and has a variety of pharmacological activities. The effect of agrimol B on CDDP-induced renal toxicity has not been determined. To investigate whether agrimol B has a protective effect against CDDP-induced AKI, we first identify Sirtuin 1 (Sirt1) as a critical target protein of agrimol B in regulating AKI through network pharmacology analysis. Subsequently, the AKI mouse model is induced by administering a single dose of CDDP via intraperitoneal injection. By detecting the serum urea nitrogen and creatinine levels, as well as the histopathological changes, we confirm that agrimol B effectively reduces CDDP-induced AKI. In addition, treatment with agrimol B counteracts the increase in renal malondialdehyde level and the decrease in superoxide dismutase (SOD), catalase and glutathione levels induced by CDDP. Moreover, western blot results reveal that agrimol B upregulates the expressions of Sirt1, SOD2, nuclear factor erythroid2-related factor 2, and downstream molecules, including heme oxygenase 1 and NAD(P)H quinone dehydrogenase 1. However, administration of the Sirt1 inhibitor EX527 abolishes the effects of agrimol B. Finally, we establish a tumor-bearing mouse model and find that agrimol B has a synergistic antitumor effect with CDDP. Overall, agrimol B attenuates CDDP-induced AKI by activating the Sirt1/Nrf2 signaling pathway to counteract oxidative stress, suggesting that this compound is a potential therapeutic agent for the treatment of CDDP-induced AKI.
Assuntos
Injúria Renal Aguda , Butanonas , Cisplatino , Fenóis , Camundongos , Animais , Cisplatino/toxicidade , Sirtuína 1/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/tratamento farmacológico , Injúria Renal Aguda/prevenção & controle , Transdução de Sinais , Rim/metabolismo , Estresse OxidativoRESUMO
Invasive fruit flies (Diptera: Tephritidae) pose a serious threat to the production and export of many commercially important fruits and vegetables. Detection of the agricultural pests Bactrocera dorsalis (Hendel) and Zeugodacus cucurbitae (Coquillett) relies heavily on traps baited with male-specific attractants. For B. dorsalis, traps are typically baited with liquid methyl eugenol (ME), and for Z. cucurbitae, traps are baited with liquid cue-lure (CL). Operating large-scale trapping networks is costly, consequently, there is much interest in identifying ways to maintain network sensitivity while reducing costs. One cost-cutting approach is the possibility of combining different male lures in the same dispenser, thus reducing the number of traps requiring servicing. The chief objective of this study was to compare captures of B. dorsalis and Z. cucurbitae males in Jackson traps baited with polymeric wafers impregnated with both ME and raspberry ketone (RK, a hydrolyzed form of CL) versus traps baited with liquid ME or CL freshly applied to cotton wicks. Captures were measured when the ME/RK wafers had been weathered for 12, 18, or 24 wk. Captures of B. dorsalis and Z. cucurbitae males were similar between fresh lure and weathered wafers over all trapping periods, with a single exception apparently due to the lessened potency of the associated killing agent. The residual amount and release rate of ME and RK from the wafers were also measured to examine possible relationships between wafer chemistry and trap catch. The possible implications of the present results to area-wide trapping programs are discussed.
Assuntos
Eugenol , Controle de Insetos , Longevidade , Tephritidae , Animais , Tephritidae/efeitos dos fármacos , Tephritidae/fisiologia , Masculino , Controle de Insetos/métodos , Controle de Insetos/instrumentação , Eugenol/farmacologia , Eugenol/análogos & derivados , Longevidade/efeitos dos fármacos , Butanonas/farmacologia , Feromônios/farmacologiaRESUMO
The soil-dwelling bacterium Pseudomonas putida S16 can survive on nicotine as its sole carbon and nitrogen source. The enzymes nicotine oxidoreductase (NicA2) and pseudooxynicotine amine oxidase (Pnao), both members of the flavin-containing amine oxidase family, catalyze the first two steps in the nicotine catabolism pathway. Our laboratory has previously shown that, contrary to other members of its enzyme family, NicA2 is actually a dehydrogenase that uses a cytochrome c protein (CycN) as its electron acceptor. The natural electron acceptor for Pnao is unknown; however, within the P. putida S16 genome, pnao forms an operon with cycN and nicA2, leading us to hypothesize that Pnao may also be a dehydrogenase that uses CycN as its electron acceptor. Here we characterized the kinetic properties of Pnao and show that Pnao is poorly oxidized by O2, but can be rapidly oxidized by CycN, indicating that Pnao indeed acts as a dehydrogenase that uses CycN as its oxidant. Comparing steady-state kinetics with transient kinetic experiments revealed that product release primarily limits turnover by Pnao. We also resolved the crystal structure of Pnao at 2.60 Å, which shows that Pnao has a similar structural fold as NicA2. Furthermore, rigid-body docking of the structure of CycN with Pnao and NicA2 identified a potential conserved binding site for CycN on these two enzymes. Taken together, our results demonstrate that although Pnao and NicA2 show a high degree of similarity to flavin containing amine oxidases that use dioxygen directly, both enzymes are actually dehydrogenases.
Assuntos
Proteínas de Bactérias , Oxirredutases , Pseudomonas putida , Proteínas de Bactérias/metabolismo , Butanonas , Citocromos c/metabolismo , Flavinas/metabolismo , Cinética , Monoaminoxidase/metabolismo , Nicotina/análogos & derivados , Nicotina/química , Oxirredutases/metabolismo , Pseudomonas putida/enzimologiaRESUMO
Transcription is a highly dynamic process that generates single-stranded DNA (ssDNA) in the genome as 'transcription bubbles'. Here we describe a kethoxal-assisted single-stranded DNA sequencing (KAS-seq) approach, based on the fast and specific reaction between N3-kethoxal and guanines in ssDNA. KAS-seq allows rapid (within 5 min), sensitive and genome-wide capture and mapping of ssDNA produced by transcriptionally active RNA polymerases or other processes in situ using as few as 1,000 cells. KAS-seq enables definition of a group of enhancers that are single-stranded and enrich unique sequence motifs. These enhancers are associated with specific transcription-factor binding and exhibit more enhancer-promoter interactions than typical enhancers do. Under conditions that inhibit protein condensation, KAS-seq uncovers a rapid release of RNA polymerase II (Pol II) from a group of promoters. KAS-seq thus facilitates fast and accurate analysis of transcription dynamics and enhancer activities simultaneously in both low-input and high-throughput manner.
Assuntos
Aldeídos/química , DNA de Cadeia Simples/análise , DNA de Cadeia Simples/química , Elementos Facilitadores Genéticos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Regiões Promotoras Genéticas , Análise de Sequência de DNA/métodos , Animais , Butanonas , DNA de Cadeia Simples/genética , Regulação da Expressão Gênica , Humanos , Camundongos , Transcrição GênicaRESUMO
ABSTRACT: Eutylone is an emerging synthetic stimulant that is quickly gaining popularity due to its affordability and wide availability. A recent surge has been observed in Upstate New York. This study presents a retrospective review of deaths in which eutylone was identified in postmortem samples from January 2018 to December 2021 in the electronic database of the Onondaga County medical examiner's office in Syracuse, NY. Of the 176 subjects who met the study criteria, 128 (73%) were male and 48 (27%) were female, with a mean age of 37.6 years. Most of the subjects were listed as White (89%), followed by African American (9%). Most of the cases had multiple medical comorbidities (89%), with anxiety and hypertension being the most common illnesses. Chromatography/mass spectrometry was used to perform a qualitative analysis of femoral blood and urine samples to detect multiple drugs, including eutylone. Substance abuse disorder was present in 135 (77%) cases, with opiates and cocaine being the most common additional drugs detected. The most common cause and manner of death were drug toxicity and accident, in 137 (78%) and 143 (81%) cases, respectively. Overall, the study suggests that eutylone is a growing concern in Upstate New York, and its use is increasing in prevalence. Policymakers and health care providers should take steps to address this emerging issue and prevent further harm to individuals and communities affected by drug overdose.
Assuntos
Butanonas , Overdose de Drogas , Transtornos Relacionados ao Uso de Substâncias , Adulto , Feminino , Humanos , Masculino , New York , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Butanonas/toxicidadeRESUMO
Early detection of biomarkers in lung cancer is one of the best preventive strategies. Although many attempts have been made to understand the early events of lung carcinogenesis including cigarette smoking (CS) induced lung carcinogenesis, the integrative metabolomics and next-generation sequencing approaches are lacking. In this study, we treated the female A/J mice with CS carcinogen 4-[methyl(nitroso)amino]-1-(3-pyridinyl)-1-butanone (NNK) and naturally occurring organosulphur compound, diallyl sulphide (DAS) for 2 and 4 weeks after NNK injection and examined the metabolomic and DNA CpG methylomic and RNA transcriptomic profiles in the lung tissues. NNK drives metabolic changes including mitochondrial tricarboxylic acid (TCA) metabolites and pathways including Nicotine and its derivatives like nicotinamide and nicotinic acid. RNA-seq analysis and Reactome pathway analysis demonstrated metabolism pathways including Phase I and II drug metabolizing enzymes, mitochondrial oxidation and signaling kinase activation pathways modulated in a sequential manner. DNA CpG methyl-seq analyses showed differential global methylation patterns of lung tissues from week 2 versus week 4 in A/J mice including Adenylate Cyclase 6 (ADCY6), Ras-related C3 botulinum toxin substrate 3 (Rac3). Oral DAS treatment partially reversed some of the mitochondrial metabolic pathways, global methylation and transcriptomic changes during this early lung carcinogenesis stage. In summary, our result provides insights into CS carcinogen NNK's effects on driving alterations of metabolomics, epigenomics and transcriptomics and the chemopreventive effect of DAS in early stages of sequential lung carcinogenesis in A/J mouse model.
Assuntos
Neoplasias Pulmonares , Nitrosaminas , Animais , Feminino , Camundongos , Compostos Alílicos , Butanonas/metabolismo , Carcinogênese , Carcinógenos/metabolismo , Carcinógenos/toxicidade , DNA/metabolismo , Epigênese Genética , Epigenômica , Pulmão/metabolismo , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/prevenção & controle , Camundongos Endogâmicos , Nitrosaminas/metabolismo , Sulfetos , Nicotiana/efeitos adversosRESUMO
RibB (3,4-dihydroxy-2-butanone 4-phosphate synthase) is a magnesium-dependent enzyme that excises the C4 of d-ribulose-5-phosphate (d-Ru5P) as formate. RibB generates the four-carbon substrate for lumazine synthase that is incorporated into the xylene moiety of lumazine and ultimately the riboflavin isoalloxazine. The reaction was first identified by Bacher and co-workers in the 1990s, and their chemical mechanism hypothesis became canonical despite minimal direct evidence. X-ray crystal structures of RibB typically show two metal ions when solved in the presence of non-native metals and/or liganding non-substrate analogues, and the consensus hypothetical mechanism has incorporated this cofactor set. We have used a variety of biochemical approaches to further characterize the chemistry catalyzed by RibB from Vibrio cholera (VcRibB). We show that full activity is achieved at metal ion concentrations equal to the enzyme concentration. This was confirmed by electron paramagnetic resonance of the enzyme reconstituted with manganese and crystal structures liganded with Mn2+ and a variety of sugar phosphates. Two transient species prior to the formation of products were identified using acid quench of single turnover reactions in combination with NMR for singly and fully 13C-labeled d-Ru5P. These data indicate that dehydration of C1 forms the first transient species, which undergoes rearrangement by a 1,2 migration, fusing C5 to C3 and generating a hydrated C4 that is poised for elimination as formate. Structures determined from time-dependent Mn2+ soaks of VcRibB-d-Ru5P crystals show accumulation in crystallo of the same intermediates. Collectively, these data reveal for the first time crucial transient chemical states in the mechanism of RibB.
Assuntos
Transferases Intramoleculares , Riboflavina , Butanonas , Formiatos , Transferases Intramoleculares/química , Fosfatos , Riboflavina/biossíntese , Riboflavina/química , Riboflavina Sintase/químicaRESUMO
Nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a Group 1 human carcinogen, as classified by the International Agency for Research of Cancer (IARC), and plays a significant role in lung carcinogenesis. However, its carcinogenic mechanism has not yet been fully elucidated. In this study, we performed colony formation assays, soft-agar assays, and tumor growth in nude mice to show that 100 mg/L NNK facilitates the malignant transformation of human bronchial epithelial Beas-2B cells. Transcriptome sequencing showed that insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), a post-transcriptional regulator, was differentially expressed in NNK-induced malignant transformed Beas-2B cells (2B-NNK cells). Small interfering RNA (SiRNA) was used to downregulate the expression of the IGF2BP1 gene. The reduction in protein expression, cell proliferation rate, and colony-forming ability and the increase in the apoptosis rate of Beas-2B cells transfected with the SiRNA indicated a role for IGF2BP1 in NNK-induced malignant transformation. IGF2BP1 is an N6-methyladenosine (m6A) regulatory factor, but it is not known whether its association with m6A mediates the malignant transformation of cells. Therefore, we measured the overall levels of m6A in Beas-2B cells. We found that the overall m6A level was lower in 2B-NNK cells, and knocking down IGF2BP1, the overall level of m6A was restored. Hence, we concluded that IGF2BP1 is involved in the NNK-induced malignant transformation of Beas-2B cells, possibly via m6A modification. This study therefore contributes novel insights into the environmental pathogenesis of lung cancer and the gene regulatory mechanisms of chemical carcinogenesis.
Assuntos
Brônquios/efeitos dos fármacos , Butanonas/farmacologia , Transformação Celular Neoplásica/genética , Células Epiteliais/efeitos dos fármacos , Metiltransferases/metabolismo , Nicotiana/efeitos adversos , Nitrosaminas/farmacologia , Proteínas de Ligação a RNA/genética , Adulto , Idoso , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Carcinógenos/farmacologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Transformação Celular Neoplásica/induzido quimicamente , Regulação para Baixo/fisiologia , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/genética , Humanos , Pulmão/efeitos dos fármacos , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/genética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Pessoa de Meia-Idade , Transfecção/métodosRESUMO
RNA secondary structure is critical to RNA regulation and function. We report a new N3-kethoxal reagent that allows fast and reversible labeling of single-stranded guanine bases in live cells. This N3-kethoxal-based chemistry allows efficient RNA labeling under mild conditions and transcriptome-wide RNA secondary structure mapping.
Assuntos
Aldeídos/química , RNA/química , Animais , Butanonas , Células-Tronco Embrionárias , Guanina/química , Células HeLa , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Camundongos , Conformação de Ácido Nucleico , Ácidos Nucleicos Heteroduplexes , Dobramento de RNA , TranscriptomaRESUMO
Tobacco smoke is a complex mixture of more than 7000 chemicals, of which many are toxic and/or carcinogenic. Many hazard assessments of tobacco have focused on individual chemical exposures without consideration of how the chemicals may interact with one another. Two chemicals, the human carcinogen 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK) and a possible human carcinogen, acrolein, were hypothesized to interact with one another, possibly owing to the additive effects of DNA adduct formation or influence on the repair of mutagenic DNA adducts. To test our hypothesis that coexposure to NNK and acrolein is more carcinogenic than either chemical alone, A/J mice were exposed to NNK (i.p., 0, 2.5, or 7.5 µmol in saline) in the presence or absence of inhaled acrolein (15 ppmV). While the single 3 h exposure to acrolein alone did not induce lung adenomas, it significantly enhanced NNK's lung carcinogenicity. In addition, mice receiving both NNK and acrolein had more adenomas with dysplasia or progression than those receiving only NNK, suggesting that acrolein may also increase the severity of NNK-induced lung adenomas. To test the hypothesis that the interaction was due to effects on DNA adduct formation and repair, NNK- and acrolein pulmonary DNA adduct levels were assessed. There was no consistent effect of the coexposure on NNK-derived DNA adducts, and acrolein DNA adducts were not elevated above endogenous levels. This study supports the hypothesis that tobacco smoke chemicals combine to contribute to the carcinogenic potency of tobacco smoke, and the mechanism of interaction cannot be explained by alterations of DNA adduct levels.
Assuntos
Adenoma , Neoplasias Pulmonares , Nitrosaminas , Poluição por Fumaça de Tabaco , Acroleína/toxicidade , Animais , Butanonas , Carcinogênese/induzido quimicamente , Carcinógenos/toxicidade , Adutos de DNA , Humanos , Pulmão , Neoplasias Pulmonares/induzido quimicamente , Camundongos , Nitrosaminas/toxicidade , Fumaça , NicotianaRESUMO
The rotational spectra of 4-hydroxy-2-butanone and its monohydrate were investigated by Fourier transform microwave spectroscopy complemented by quantum chemical calculations. One conformer of 4-hydroxy-2-butanone, with the intramolecular O-Hâ¯O hydrogen bond, has been observed in the pulsed jet. Rotational spectra of the six isotopologues (including four 13C and one 18O mono-substitution species) in natural abundance were measured and assigned, enabling the accurate structural determination of the molecular skeleton. The most stable isomer of its monohydrate, in which water inserts into the intramolecular hydrogen bond and serves the dual role of being a proton donor and acceptor, was also detected. The rotational spectra of HOD, DOH, D2O and H218O isotopologues were also measured allowing the accurate evaluation of the parameters of the intermolecular hydrogen bonds. This rotational spectroscopic investigation demonstrates that upon complexation, the weak intramolecular hydrogen bond in the monomer is replaced by two strong intermolecular O-Hâ¯O hydrogen bonds, leading to a change in the orientation of the -OH group of 4-hydroxy-2-butanone.
Assuntos
Butanonas/química , Micro-Ondas , Água , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Imageamento de Micro-Ondas , Espectroscopia de Infravermelho com Transformada de Fourier , Água/químicaRESUMO
The detection of volatile organic compounds by gas sensors is of great interest for environmental quality monitoring and the early-stage and noninvasive diagnosis of diseases. Experiments found hexane, toluene, aniline, butanone, acetone, and propanol gases in the exhaled breath of patients suffering from COVID-19, lung cancer, and diabetes. However, no studies are available to systematically elucidate the selectivity of these gases on nanosheets of zinc oxide for chemiresistive and direct thermoelectric gas sensors. Therefore, this work performed the elucidation by studying the electronic, electrical, and thermal properties of the bilayered ZnO nanosheets with polar (0001) and non-polar (112Ì0) surfaces under the adsorption of the gases. The interaction between the gases and the nanosheets belongs to two groups: electrostatic attraction and charge exchange. The second one occurs due to the peak resonance of the same type of orbitals between the substrates and the gases along the surface normal and the first one for the other cases. The characteristics of the Seebeck coefficient exhibited distinct selectivity of butanone and acetone.
Assuntos
COVID-19 , Compostos Orgânicos Voláteis , Óxido de Zinco , Acetona/química , Butanonas , Gases , Humanos , Óxido de Zinco/químicaRESUMO
Criegee intermediates are important atmospheric oxidants, formed via the reaction of ozone with volatile alkenes emitted into the troposphere. Small Criegee intermediates (e.g., CH2OO and CH3CHOO) are highly reactive, and their removal via unimolecular decay or bimolecular chemistry dominates their atmospheric lifetimes. As the molecular complexity of Criegee intermediates increases, their electronic absorption spectra show a bathochromic shift within the solar spectrum relevant to the troposphere. In these cases, solar photolysis may become a competitive contributor to their atmospheric removal. In this article, we report the conformer-dependent simulated electronic absorption spectra of two four-carbon-centered Criegee intermediates, methyl vinyl ketone oxide (MVK-oxide) and methacrolein oxide (MACR-oxide). Both MVK-oxide and MACR-oxide contain four low-energy conformers, which are convoluted in the experimentally measured spectra. Here, we deconvolute each conformer and estimate contributions from each of the four conformers to the experimentally measured spectra. We also estimate the photolysis rates and predict that solar photolysis should be a more competitive removal process for MVK-oxide and MACR-oxide (cf. CH2OO and CH3CHOO).
Assuntos
Eletrônica , Óxidos , Acroleína/análogos & derivados , Butanonas , FotóliseRESUMO
Atmospheric ozonolysis of biogenic and anthropogenic alkenes generates zwitterionic carbonyl oxide intermediates (R1R2CâO+O-), known as Criegee intermediates, with different structural motifs and conformations. This study reports a systematic laboratory study of substituent effects on the electronic spectroscopy of four-carbon Criegee intermediates (CIs) with methyl-ethyl (MECI) and isopropyl (IPCI) groups, which are isomers produced in ozonolysis of asymmetric branched alkenes. The four-carbon CIs are separately generated by an alternative synthetic route, and spectroscopically characterized on the strong π* â π transition associated with the carbonyl oxide group in a pulsed supersonic expansion with VUV photoionization at 118 nm and UV-induced depletion of the m/z 88 signal. The resultant broad and unstructured UV spectral features for MECI and IPCI are peaked at ca. 320 and 330 nm, respectively, with large absorption cross-sections of ca. 10-17 cm2. Comparisons are made with the four-carbon CIs formed in isoprene ozonolysis, methyl vinyl ketone oxide (MVK-oxide) and methacrolein oxide (MACR-oxide), which have the same backbone connectivity as MECI and IPCI but have extended conjugation across the vinyl and carbonyl groups. A remarkable 50 nm shift of the peak absorption to longer wavelength is observed for MVK-oxide and MACR-oxide compared to MECI and IPCI, respectively. Vertical excitation energies computed theoretically agree well with the experimental findings, confirming that the spectral shifts are caused by the extended π conjugation in the isoprene-derived Criegee intermediates.
Assuntos
Carbono , Ozônio , Acroleína/análogos & derivados , Alcenos/química , Butadienos , Butanonas , Eletrônica , Hemiterpenos , Óxidos , Ozônio/química , Análise EspectralRESUMO
A novel D-π-A type fluorescent probe (probe 1) was developed for water content detection in organic solvents. By analyzing the relationship between fluorescence and water content, the probe was successfully applied to determine trace water content in tetrahydrofuran, ethyl acetate, 2-butanone, acetone, dimethylformamide, and acetonitrile. High water content in THF and ethyl acetate was associated with a gradual colour change from yellowish green to earthy yellow. The red/green value had a linear relationship with the water content in THF and ethyl acetate. There was a linear relationship between the red/blue value and water content in 2-butanone and acetone. Furthermore, probe 1 could be used for human serum albumin detection. Unexpectedly, probe 1 had a different colour response in deuterated and nondeuterated solvents, and had different fluorescence intensity and fluorescence emission wavelength. Probe 1 is rare tool that can distinguish between deuterated and nondeuterated reagents.
Assuntos
Corantes Fluorescentes , Água , Acetatos , Acetona , Butanonas , Humanos , SolventesRESUMO
The current investigation was accomplished to evaluate the hepatoprotective effect of White tea and Raspberry Ketone against toxicity induced by acrylamide in rats. Sixty adult male rats were divided randomly into group (I) control; group (II) rats received RK with dose (6 mg/kg/day); Group III: rats received 5 ml of WT extract/kg/day; Group IV rats received AA (5 mg/kg/day); Group V: rats administrated with both AA (5 mg/kg/day) and RK (6 mg/kg/day) and Group VI: rats administrated AA (5 mg/kg/day) and 5 ml of WT extract/kg/day. The biochemical assays exhibited a significant increase in serum levels of Adiponectin, AST, ALT, ALP of the group treated with acrylamide if compared to the control group and an improvement in their levels of groups V and VI. The histopathological and immunohistochemical findings confirm the biochemical observations. In conclusion, the present investigation proved that the supplementation of WT and RK enhanced the liver histology, immunohistochemistry and biochemistry against the oxidative stress induced by acrylamide.