Six New Antimicrobial Metabolites from the Deep-Sea Sediment-Derived Fungus Aspergillus fumigatus SD-406

Six new metabolites, including a pair of inseparable mixtures of secofumitremorgins A (1a) and B (1b), which differed in the configuration of the nitrogen atom, 29-hydroxyfumiquinazoline C (6), 10R-15-methylpseurotin A (7), 1,4,23-trihydroxy-hopane-22,30-diol (10), and sphingofungin I (11), together with six known compounds (2–5 and 8–9), were isolated and identified from the deep-sea sediment-derived fungus Aspergillus fumigatus SD-406. Their structures were determined by detailed spectroscopic analysis of NMR and MS data, chiral HPLC analysis of the acidic hydrolysate, X-ray crystallographic analysis, J-based configuration analysis, and quantum chemical calculations of ECD, OR, and NMR (with DP4+ probability analysis). Among the compounds, 1a/1b represent a pair of novel scaffolds derived from indole diketopiperazine by cleavage of the amide bond following aromatization to give a pyridine ring. Compounds 1, 4, 6, 7, 10 and 11 showed inhibitory activities against pathogenic bacteria and plant pathogenic fungus, with MIC values ranging from 4 to 64 μg/mL.

Diacetyl and Other Ketones in e-Cigarette Aerosols: Some Important Sources and Contributing Factors

Background: Concerns over the presence of the diketones 2,4 butanedione (DA) and 2,3 pentanedione (AP) in e-cigarettes arise from their potential to cause respiratory diseases. Their presence in e-liquids is a primary source, but they may potentially be generated by glycerol (VG) and propylene glycol (PG) when heated to produce aerosols. Factors leading to the presence of AP, DA and acetoin (AC) in e-cigarette aerosols were investigated. We quantified direct transfer from e-liquids, examined thermal degradation of major e-liquid constituents VG, PG and 1,3 propanediol (1,3 PD) and the potential for AC, AP and DA production from sugars and flavor additives when heated in e-cigarettes.Method: Transfers of AC, AP and DA from e-liquids to e-cigarette aerosols were quantified by comparing aerosol concentrations to e-liquid concentrations. Thermal generation from VG, PG or 1,3 PD e-liquids was investigated by measuring AC, AP and DA emissions as a function of temperature in an e-cigarette. Thermal generation of AC, AP and DA from sugars was examined by aerosolising e-liquids containing sucrose, fructose or glucose in an e-cigarette. Pyrolytic formation of AP and DA from a range of common flavors was assessed using flash pyrolysis techniques.Results: AC transfer efficiency was >90%, while AP and DA were transferred less efficiently (65%) indicating losses during aerosolisation. Quantifiable levels of DA were generated from VG and PG, and to a lesser extent 1,3 PD at coil temperatures >300°C. Above 350°C AP was generated from VG and 1,3 PD but not PG. AC was not generated from major constituents, although low levels were generated by thermal reduction of DA. Aerosols from e-liquids containing sucrose contained quantifiable (>6 ng/puff) levels of DA at all sucrose concentrations tested, with DA emissions increasing with increasing device power and concentration. 1% glucose, fructose or sucrose e-liquids gave comparable DA emissions. Furanose ring compounds also generate DA and AP when heated to 250°C.Conclusions: In addition to less than quantitative direct transfer from the e-liquid, DA and AP can be present in the e-cigarette aerosol due to thermal decomposition reactions of glycols, sugars and furanonse ring flavors under e-cigarette operating conditions.

Sources of PM2.5-Associated PAHs and n-Alkanes in Changzhou China

Polycyclic aromatic hydrocarbons (PAHs) and n-alkanes are important specific organic constituents in fine particulate matter (PM2.5). Seventy-five PM2.5 samples were collected in Spring Changzhou, to investigate the concentrations and sources of n-alkanes (C9–C40) and PAHs. The average concentrations of total PAHs (∑PAHs) and n-alkanes (∑n-alkanes) were 4.37 ± 4.95 ng/m3 and 252.37 ± 184.02 ng/m3, ranging from 0.43 to 22.22 ng/m3 and 57.37 to 972.17 ng/m3, respectively. The average concentrations of ∑n-alkanes and ∑PAHs were higher in severely polluted days (PM2.5 ≥ 150 μg/m3) in comparison to other days. Up to 85% of PAHs were four- and five-ring compounds, and the middle-chain-length n-alkanes (C25–C35) were the most abundant species (80.9%). The molecular distribution of n-alkanes was characterized by odd-number carbon predominance (carbon preference index, CPI > 1), with a maximum centered at C27, C29, and C31 revealing a significant role of biogenic sources. Principal component analysis suggested that the biogenic sources that contributed the most to n-alkanes and PAHs were from coal combustion (46.3%), followed by biomass burning (16.0%), and vehicular exhaust (10.3%). The variation in the concentration of n-alkanes and PAHs from different air mass transports was not agreement with the change in PM2.5 mass, indicating that regional transport had important impacts on the characterization of PM2.5. The results of our study can provide useful information for evaluating the influence of anthropogenic and biogenic activities on organic matters (n-alkanes and PAHs).

Recent Advancements in the Synthesis and Chemistry of Benzo-fused Nitrogen- and Oxygen-based Bioactive Heterocycles

: Since a variety of benzo-fused nitrogen- and oxygen-based bioactive heterocyclic moieties are present in the form of benzoxazinones, spirooxindole-based heterocyclic compounds, coumarin-fused heterocyclic compounds and 2H-indazoles. This review article briefly describes some of the significant advancements and developments in the area of 1,4-benzoxazine-3-ones, 1,4-benzoxazin-2-ones, spiropyrrolidine and spiropyrrolizine-based ring compounds, coumarin-fused compounds, benzopyran-fused coumarins, and a 2H-indazoles class of bioheterocycles. Thus, keeping in view the medicinal importance of these bioactive benzo-fused heterocycles, particular attention has been given to their synthesis and medicinal/pharmaceutical properties in detail.

Polycyclic Aromatic Hydrocarbons in Costal Sediments and Indian Halibuts of Asaluyeh, Kangan, Khark, Emam Hasan and Bushehr Coasts, Iran: Distribution Pattern and Health Risk Assessment

A total 20 sediment and 20 Indian halibut samples were sampled from Asaluyeh, Kangan, Khark, Emam Hasan and Bushehr coast, Bushehr province, Iran for studying distribution and health risk assessment of polycyclic aromatic hydrocarbons (PAHs). PAHs were analyzed using HPLC. The mean ƩPAHs concentrations in sediment and Indian halibut samples were 6.894 ± 1.4301 and 14.807 ± 7.486 mg/kg, respectively. There was a significant positive relationship (P < 0.05) between ƩPAHs, 2–3 ring compounds, and 4 ring compounds in the sediments and Indian halibut samples. ƩPAHs concentration in sediments and Indian halibuts was higher in Asaluyeh area followed by Khark area. The values of PAHs pollution in the Bushehr province coastline were low to very high. The toxic equivalent quotient (TEQ), excess cancer risk (ECR), and the incremental lifetime cancer risk (ILCR) were applied for health risk assessment. Based on TEQ calculation, DA was a good marker in assessing PAHs related to health risk. DDI values for ∑PAHs and ∑CPAHs (carcinogenic PAHs) were also highest in Asaluyeh and Kangan, respectively. ILCR values for sediments in 10% of all stations and cumulative ECR values for Indian halibuts in all studied areas exceeded the USEPA acceptable level thus suggesting a potential cancer risk. Thus, regular monitoring of PAHs pollutants in the coastlines of Bushehr province is recommended.

Different biological strategies for the bioremediation of naturally polluted soils

Finding an appropriate method with the highest rate of polycyclic aromatic hydrocarbon (PAH) removal from naturally polluted soils is an important research issue. A pot factorial experiment (using contaminated soil samples from the Isfahan Refinery, Iran) was conducted in a 90-day period to compare the following bioremediation strategies: (1) natural attenuation (NA): the inherent ability of soil for bioremediation; (2) bioaugmentation (BA): inoculating soil with PAH degrading microbes Marinobacter hydrocarbonoclasticus; (3) biostimulation (BS): using N, P and K nutrients for the stimulation of bioremediating soil bacteria to achieve the C : N : P ratio of 100 : 10 : 1, and(4) bioaugmentation + biostimulation (BS + BA). Treatments NA (22.8%) and BA + BS (63.9%) resulted in the least and the highest rate of PAH removal from the soil. The 2–4 ring compounds had a significantly (P ≤ 0.05) higher rate of degradation than the 5–6 ring compounds. The highest rates were resulted by fluorene (76.41%) and acenaphthylene (72.28%) using the BA + BS treatment. However, the lowest degradation rates were resulted by indeno (1,2,3-cd) pyrene (10.05%), benzo [b] fluoranthene (10.17%), benzo (g, h, i) perylene (12.53%), and benzo [k] fluoranthene (13.67%), using NA treatment. The BA + BS treatments are the most effective method for the bioremediation of PAH polluted soils.

Enantioselective Functionalization of Prochiral Cyclobutanones and Cyclobutenones

Enantioselective synthesis of cyclobutane derivatives is still a challenging topic in asymmetric synthesis. [2+2]-Cycloaddition and skeleton rearrangement are two primary strategies to this end. Recently, functionalization of cyclobutanones and cyclobutenones, which are readily available via [2+2]-cycloadditions as prochiral substrates, has emerged as a powerful tool to access versatile four-membered ring compounds. Herein, we summarize some recent advances in these areas from our and other groups.

Ultrasonically assisted macrocyclic ring compound coatings for corrosion protection of copper in 3.5% NaCl solution

ABSTRACT: Macrocyclic ring compounds are potential corrosion inhibitors due to their high planarity, rigidity, and presence of many heteroatoms such as nitrogen, oxygen, phosphorus, and sulfur. However, their application as corrosion inhibitors has been faced with a challenge of insolubility in most organic and aqueous solvents. To overcome this challenge and to harness the untapped hydrophobic property of these compounds, this research, via ultrasonication method dispersed a macrocyclic ring compound known as free-based Phthalocyanine (Pc) to fabricate a corrosion-resistant coating on the Cu surface. The Cu samples were coated through a 24 h immersion by self-assembly method in different systems of sonicated and non-sonicated solutions of the compound in dimethyl sulfoxide (DMSO). The effect of sonication and immersion duration on the coating morphology, compactness, and consequent corrosion inhibition was analyzed. Electrochemical and surface imaging techniques revealed higher corrosion protection in 3.5% NaCl for the Pc coated Cu samples after sonication compared to the non-sonicated systems.