Synthesis and laccase-mediated oxidation of new condensed 1,4-dihydropyridine derivatives

We describe herein the synthesis and laccasemediated oxidation of six novel 1,4-dihydropyridine (DHP)-based hexahydroquinolines (DHP1-DHP3) and decahydroacridines (DHP4-DHP6). We employed different laccase enzymes with varying redox potential to convert DHP1-DHP3 and DHP4- DHP6 to the corresponding pyridine-containing tetrahydroquinoline and octahydroacridine derivatives, respectively. Intensively coloured products were detected in all biocatalytic reactions using laccase from Trametes versicolor (TvLacc), possibly due to the presence of conjugated chromophores formed in products after oxidation. The NMR assessment confirmed that the oxidation product of DHP1 was its corresponding pyridine-bearing tetrahydroquinoline derivative. Laccase from Bacillus subtillis (BacillusLacc) was the most efficient enzyme for this group of substrates using HPLC assessment. Overall, it could be concluded that DHP2 and DHP5, bearing catecholic structures, were easily oxidized by all tested laccases, while DHP3 and DHP6 containing electron-withdrawing nitro-groups are not readily oxidized by laccases. DHP4 with decahydroacridine moiety consisting of three condensed six-membered rings that contribute not only to the volume but also to the higher redox potential of the substrate rendered this compound not to be biotransformed with any of the mentioned enzymes. Overall, we showed that multiple analytical approaches are needed in order to assess biocatalytical reactions

Degradabilnost normalnih alkana za vreme ex situ prirodne bioremedijacije zemljišta zagađenog mazutom

It is well known that during biodegradation of oil under natural geological conditions, or oil pollutants in the environment, degradation of hydrocarbons occurs according to a well-defined sequence. For example, the major changes during the degradation process of n-alkanes occur in the second, slight and third, moderate level (on the biodegradation scale from 1 to 10). According to previous research, in the fourth, heavy level, when intensive changes of phenanthrene and its methyl isomers begin, n-alkanes have already been completely removed. In this paper, the ex situ natural bioremediation (non-stimulated bioremediation, without addition of biomass, nutrient substances and biosurfactant) of soil contaminated with heavy residual fuel oil (mazut) was conducted during a period of 6 months. Low abundance of n-alkanes in the fraction of total saturated hydrocarbons in the initial sample (identification was possible only after concentration by the urea adduction technique) showed that the investigated oil pollutant was at the boundary between the third and the fourth biodegradation level. During the experiment, an intense degradation of phenanthrene and its methyl-, dimethyl- and trimethyl-isomers was not accompanied by the removal of the remaining n-alkanes. The abundance of n-alkanes remained at the initial low level, even at end of the experiment when the pollutant reached one of the highest biodegradation levels. These results showed that the non-stimulated biodegradation of some hydrocarbons, despite their high biodegradability, had not proceeded completely to the end, even at final degradation stages. Under the condition of reduced availability of some hydrocarbons, microorganisms tend to opt for the less biodegradable but more accessible hydrocarbons.Dobro je poznato da se u toku biodegradacije nafte u prirodnim geološkim uslovima, ili naftnog zagađivača u životnoj sredini, degradacija ugljovodonika odigrava prema definisanom rasporedu. Na primer, glavne promene u procesu razgradnje normalnih alkana dešavaju se u toku drugog, "blagog", i trećeg, "umerenog", stupnja (na skali biodegradacije od 1 do 10). Prema dosadašnjim istraživanjima, u četvrtom stupnju, kada počinju intenzivne promene fenantrena i njegovih metil izomera, normalni alkani su već u potpunosti uklonjeni. U ovom radu u toku perioda od 6 meseci izvođena je ex situ prirodna bioremedijacija (nestimulisana bioremedijacija bez dodatka biomase, hranljivih sastojaka i biosurfaktanata) zemljišta zagađenog mazutom. Niska obilnost normalnih alkana u frakciji ukupnih zasićenih alkana u početnom uzorku (identifikacija je bila mogućna tek nakon koncentrovanja pomoću karbamida) pokazala je da je ispitivani naftni zagađivač na granici između trećeg i četvrtog stupnja biodegradacije. Tokom eksperimenta, intenzivnu razgradnju fenantrena i njegovih metil, dimetil i trimetil izomera nije pratilo uklanjanje ostatka normalnih alkana. Njihova obilnost je ostala na početnom, niskom nivou i na kraju eksperimenta kada je zagađivač dostigao jedan od najviših stepena biodegradacije. Dobijeni rezultati su pokazali da se razgradnja pojedinih ugljovodonika uprkos njihovoj visokoj biodegradabilnosti ne odigrava do potpunog kraja ni u završnim fazama degradacije. U uslovima njihove smanjene dostupnosti, mikroorganizmi se opredeljuju za teže degradabilne, ali dostupnije ugljovodonike

Novel 90Sr-90Y generator system based on a cross-flow hollow fiber supported liquid membrane contactor

Separation of yttrium(III) from strontium(II) with 15% (v/v) di(2-ethylhexyl)phosphoric acid (DEHPA) in dodecane was carried out in a hollow fiber supported liquid membrane (SLM) extraction system operated under closed-loop recirculation of the donor and acceptor phase. The donor phase was a mixture of 5.7 mmol dm-3 of Sr(II) and 0.23 mmol dm-3 of Y(III) in 0.1 mol dm-3 HCl, the acceptor solution was 3 mol dm-3 HCl, and the donor to acceptor phase volume ratio was 6.2. At the donor flow rate of 4.7 cm3 min-1 and the acceptor flow rate of 0.8 cm3 min-1, the yield of Y(III) in the acceptor phase reached 60% after 360 min with a molar ratio of Y(III) to Sr(II) in the acceptor of 250:1, as compared to 1:25 in the donor phase. The yield of Y(III) was 72% at the acceptor flow rate to 1.9 cm3 min-1, but a breakthrough of Sr(II) through liquid membrane increased from 0.02 to 0.2%

Antioxidant and Antiproliferative Activity of Allium ursinum and Their Associated Microbiota During Simulated in vitro Digestion in the Presence of Food Matrix

In this study, for the first time, the comprehensive analysis of antiproliferative and antioxidant activities of ramson, followed by the analysis of its associated microbiota and health-promoting effects of lactic acid bacteria (LAB), was performed. Ramson (Allium ursinum) is recognized as a medicinal plant with a long history of use in traditional medicine due to its antimicrobial and antioxidant activity. In this study the influence of in vitro gastrointestinal digestion on the cytotoxic activity of A. ursinum extracts against human malignant cell lines was demonstrated. Seven sulfur compounds, the degradation products of thiosulfinates, including diallyl disulfide were shown to inhibit proliferation of malignant cells by inducing accumulation within G2/M phase as well as to induce apoptosis through activation of caspase-3 and mitochondrial signaling pathway. Further, the A. ursinum microbiota, particularly LAB with potential probiotic effects, was analyzed by culture-dependent method and culture-independent method [denaturing gradient gel electrophoresis (DGGE)]. The obtained results revealed that the most abundant genera were Streptococcus, Lactobacillus, and Bacillus. The Lactobacillus genus was mainly represented by L. fermentum. The pulsed-field gel electrophoresis (PFGE) analysis revealed the presence of two PFGE pulsotypes. The probiotic potential of the strain L. fermentum BGSR163 belonging to PFGE pulsotype 1 and the strain L. fermentum BGSR227 belonging to the PFGE pulsotype 2 was characterized. The results revealed that both strains are safe for human use, successfully survive the simulated gastrointestinal conditions, have potential to transiently colonize the gastrointestinal tract (GIT) and have a protective immunomodulatory effect, inducing the production of proinflammatory cytokine IL17 and regulatory cytokine IL10, while decreasing the production of proinflammatory cytokine IFN-gamma. In conclusion, the results of this study suggest that consumption of A. ursinum might have health-promoting properties, including anticancer effects, while L. fermentum strains isolated from A. ursinum leaves could be used as probiotics for human consumption

Pyrrolizidine alkaloids from seven wild-growing Senecio species in Serbia and Montenegro

The genus Senecio (family Asteraceae) is one of the largest in the world. It comprises about 1100 species which are the rich source of pyrrolizidine alkaloids. Plants containing pyrrolizidine alkaloids are among the most important sources of human and animal exposure to plant toxins and carcinogens. The pyrrolizidine alkaloids of seven Senecio species (S. erucifolius, S. othonnae, S. wagneri, S. subalpinus, S. carpathicus, S. paludosus and S. rupestris) were studied. Fourteen alkaloids were isolated and their structures determined from spectroscopic data (1H- and 13C-NMR, IR and MS). Five of them were identified in S. erucifolius, four in S. othonnae, two in S. wagneri, four in S. subalpinus, two in S. carpathicus, three in S. paludosus and three in S. rupestris. Seven pyrrolizidine alkaloids were found for the first time in particular species. The results have chemotaxonomic importance. The cytotoxic activity and antimicrobial activity of some alkaloids were also studied

Separation of yttrium from strontium by hollow fibre supported liquid membrane containing di(2-ethylhexyl)phosphoric acid

Separation of Y(III) from Sr(II) was performed using the hollow fibre membrane contactor operated in a recirculation mode. The steady-state was established after ~5 h of operation and the maximum removal of Y(III) from the donor to the acceptor was achieved at the donor flow rate of 4.7 cm3 min-1 . The investigated system showed promising results as a method which could be potentially applied for the preparation of 90Sr/ 90Y generator system

VARIJABILNOST SESKVITERPENA ETARSKIH ULJA VRSTE TEUCRIUM MONTANUM L

The aim of this study is to determine the qualitative variability and relative presence of sesquiterpene hydrocarbons in essential oils samples of Teucrium montanum L. collected from two different substrate types. Four samples of essential oils from serpentinite and four from calcareous were obtained by the method of hydrodistillation from aboveground plant parts. Based on the results, it was shown that populations from serpentinite habitats synthesize 2 times more sesquiterpenes than from calcareous ones, while the compound 6-epi-β-cubeben was detected only in populations from calcareous. Edaphic characteristics of habitats affect the qualitative composition and relative presence of sesquiterpenes in essential oils, which has a significant application in biotechnology.Publishe

Characterisation of levan and levan/gelatin blend films using AFM and FTIR spectroscopy

Food packaging concerns a preservation and protection of all types of food and therefore is important part of food technology. Today, synthetic packaging films are predominantly used, however they are very slow or only partially degradable. Due to incomplete degradation of synthetic polymers, micro and nanoplastic could be produced, which is in last year’s considered as a new threat to human health. Microbial polysaccharide levan is natural biopolymer produced by broad range of microorganisms and has promising properties such as biocompatibility, renewability, high molecular height, low viscous nature, antioxidant and prebiotic activities. Gelatine, due to its affordability, biodegradability, low cost and excellent functional and film properties is currently the most preferred protein derivative

Separation of yttrium from strontium by hollow fibre supported liquid membrane containing di(2-ethylhexyl)phosphoric acid

Separation of Y(III) from Sr(II) was performed using the hollow fibre membrane contactor operated in a recirculation mode. The steady-state was established after ~5 h of operation and the maximum removal of Y(III) from the donor to the acceptor was achieved at the donor flow rate of 4.7 cm3 min-1. The investigated system showed promising results as a method which could be potentially applied for the preparation of 90Sr/90Y generator system

Influence of oxic/anoxic condition on sorption behavior of PFOS in sediment

Sediment components and redox properties change with oxic/anoxic condition, which affect the environmental transport of perfluorooctane sulfonate (PFOS). Herein, the influence of oxic/anoxic condition on the variation of redox and residual components of sediments, where organic matter, iron and manganese oxides are separated from the original sediment collected from Lake Taihu, China, are investigated. Meanwhile, the distinguishing sorption behaviors of PFOS on various residual sediments under oxic and anoxic condition are studied. Sediment after extracting iron and manganese (S-FeMn), which possessed the highest organic carbon (0.99%), had the highest affinity for PFOS under oxic condition. However, anoxic environment resulted in an increase of the pH, dissolving of organic carbon and de-protonation of S-FeMn, which caused the lower sorption capacity of PFOS on S-FeMn. Sediment after extracting manganese (S-Mn) had the higher sorption ability in anoxic environment because the Fe2+ from S-Mn provided more effective electrostatic sites for anionic PFOS. When the environment changed to oxic condition, the iron existed as trivalent form in S-Mn, which resulted in a block of effective sorption site and reduced the sorption amounts of PFOS. The higher percentage of manganese oxides restrained the sorption of PFOS. Hence, whether or not oxic/anoxic condition promoted the PFOS sorption depended on both the percentage and form of various components in the sediment. The study generated further insight into the environmental transport of PFOS in the sediments with different properties and the wetland system, where oxic/anoxic subsurface flow was constructed