Studies on the lipolytic activity of sonicated enzymes from Yarrowia lipolytica

The aim of this study was to evaluate the efficiency of sonication in releasing protein from a widespread lipase-producing yeast, Yarrowia lipolytica KKP 379, and to examine the impact of ultrasound waves generated in a horn-type sonicator on the lipolytic activity of Y. lipolytica in the hydrolysis of p-nitrophenyl laurate. In this paper, we focused on a few parameters of ultrasound cell disruption, such as the time of sonication, acoustic power, storage time of the frozen yeast biomass used in sonication and the solvent used to suspend the yeast cells which were considered as the most important part in the process of obtaining a biocatalyst from Y. lipolytica for organic synthesis. The most effective additive in protein release proved to be 2% Tween 80; other ideal parameters of the process were ultrasonic power at 150 W for 15 min and 9 weeks of frozen biomass storage time. The sonication parameters, which were the best for protein release, did not seem to be the most effective for obtaining high lipolytic activity due to denaturation as an effect of cavitation.     

Dimorphism in 3′‐amino­cyclo­hexane­spiro‐5′‐hydantoin

The title compound [systematic name: 1′‐amino­cyclo­hexane­spiro‐4′‐imidazole‐2′,5′(3′H,4′H)‐dione], C₈H₁₃N₃O₂, has been synthesized and was found to crystallize in two different structures, both monoclinic and both with the same P2₁/c space group. In the first structure, there are two mol­ecules in the asymmetric unit, one of which uses all of its hydrogen‐bond donors and acceptors and forms undulating layers, while the other forms chains propagating perpendicular to the layers. In the second structure, there is only one independent mol­ecule and the packing is based on a chain structure mediated by hydrogen bonding between the hydantoin moieties and further grouped into hydro­philic layers separated by layers of the hydro­phobic cyclo­hex­yl groups.     

Hydro­gen‐bonding patterns in two structural isomers of 3,6‐bis(2‐chloro­phenyl)‐1,4‐di­hydro‐1,2,4,5‐tetrazine

Two structural isomers, 3,6‐bis(2‐chloro­phenyl)‐1,4‐di­hydro‐1,2,4,5‐tetrazine, (I), and 3,5‐bis(2‐chloro­phenyl)‐4‐amino‐1H‐1,2,4‐triazole, (II), both C₁₄H₁₀Cl₂N₄, form chain‐like structures in the solid state, stabilized by N—H⋯N and N—H⋯Cl hydrogen bonds. A contribution from weak interactions to the strong hydrogen‐bond network is observed in both structures. The secondary graph sets for intermolecular hydrogen bonds [(11) for (I) and (12) for (II)] indicate the similarity between the networks.     

Uranium determination in water samples with elevated salinity from Southern Poland by micro coprecipitation using alpha spectrometry

Due to the importance of water in human life, its quality must be strictly controlled; so simple and reliable analytical methods must be available. For this purpose a rapid procedure for the determination of uranium isotopes in natural water samples with elevated salinity was adopted. It was tested in 16 water samples from Upper and Lower Silesia Regions in Poland. Water samples had salinity in a range of 290–26,925 mg l^{− 1}.In water samples the concentrations of ²³⁴U and ²³⁸U ranged from 2.07 to 52.08 mBq l^{– 1} and from 2.18 to 43.38 mBq l^{– 1} respectively, while ²³⁵U level was below MDA (0.7 mBq l^{− 1}).The isotopic ratio of ²³⁴U/²³⁸U varies in the range from 0.949 to 3.344 in all investigated waters which means that there is usually no radioactive equilibrium between the parent nuclide ²³⁸U and its daughter product ²³⁴U.These results do not show a correlation between total dissolved solids (TDS) values and concentration of dissolved uranium isotopes.Committed effective dose for adults due to uranium intake as a result of drinking water usage was in range of 0.15–3.29 µSv y^{− 1} with an average value of 1.09 µSv y^{− 1} far below the 100 µSv y^{− 1} WHO recommendation.     

Gold-vanadium-niobium catalysts in environmental protection—adsorption and interaction of NO, C3H6 and O2—FT-IR study

FT-IR study of NO and C₃H₆ adsorption, co-adsorption and interaction in the presence of oxygen were performed in order to estimate the catalytic behaviour of Au and V-containing MCM-41 materials in NO-SCR with propene. MCM-41 were modified with gold, vanadium and niobium by their introduction during the synthesis (co-precipitation) carried out with the use of HCl or H₂SO₄ as pH adjustment agent. The texture/structure properties of the prepared samples were investigated by N₂ adsorption, XRD, XPS and TEM techniques. It has been found that the nature of acid used for the pH adjustment during the synthesis determines the gold particles size and dispersion and influences the interaction of NO+O₂+C₃H₆ with the catalyst surfaces. In both types of AuVMCM-41 catalysts, the SCR reaction route occurs via NO₂ formation. In the case of AuVMCM-41(HCl) and AuVNbMCM-41(HCl) nitrites are formed and stored, and upon heating NO₂ is released. These kinds of nitrites are not formed on AuVMCM-41(H₂SO₄) and AuVNbMCM-41(H₂SO₄). Instead of that NO₂ is chemisorbed on metallic gold, niobium and vanadium species and reacts with propene and/or oxygenates.     

The Antioxidant,Cytotoxic and Antimicrobial Potential of Phenolic Acids-Enriched Extract of Elicited Hairy Roots of Salvia bulleyana

Hairy root cultures are valuable sources of a range of phytochemicals. Among them, Salvia bulleyana root culture is a promising source of polyphenols, especially rosmarinic acid (RA), a phenolic acid depside with pleiotropic activity and a wide application in medicine and cosmetology. The aim of the study was to enhance the culture productivity by finding suitable elicitation protocol and to determine its biological potential in terms of antioxidant, anticancer and antimicrobial properties. The total content of phenols and the levels of particular constituents in root extracts were analyzed using HPLC-PDA. Among four elicitors tested (yeast extract; methyl jasmonate, MJA; trans-anethol; and cadmium chloride), MJA was found to be the most effective. The greatest boost in phenolic production (up to 124.4 mg/g dry weight) was observed after three-day treatment with MJA at 100 µM, with an almost 100% improvement compared to the controls (non-treated root culture). The hydromethanolic extract from the elicited culture exhibited strong antioxidant activity with IC₅₀ values of 11.1 µg/mL, 6.5 µg/mL and 69.5 µg/mL for DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid)) and superoxide anion radical, respectively. Moreover, in concentrations of 0.5–5 mg/mL the extract inhibited the growth of LoVo, AGS and HeLa cell lines, but was safe for the L929 cells up to the concentration of 5 mg/mL. The extract also exhibited moderate antimicrobial activity. Thus, the results confirmed that elicitation can be a beneficial strategy for increase the phenolic acid biosynthesis in hairy roots of S. bulleyana, and that such a highly productive culture can show significant biological potential.     

Implementing Silica Nanoparticles in the Study of the Airborne Transmission of SARS-CoV-2

Aerosol transmission constitutes one of the major transmission routes of the SARS-CoV-2 pathogen. Due to the pathogen’s properties, research on its airborne transmission has some limitations. This paper focuses on silica nanoparticles (SiO₂) of 40 and 200 nm sizes as the physicochemical markers of a single SARS-CoV-2 particle enabling experiments on the transmission of bioaerosols in public spaces. Mixtures of a determined silica concentration were sprayed on as an aerosol, whose particles, sedimented on dedicated matrices, were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Since it was not possible to quantitatively identify the markers based on the obtained images, the filters exposed with the AirSampler aspirator were analyzed based on inductively coupled plasma optical emission spectroscopy (ICP-OES). The ICP-OES method enabled us to determine the concentration of silica after extracting the marker from the filter, and consequently to estimate the number of markers. The developed procedure opens up the possibility of the quantitative estimation of the spread of the coronavirus, for example in studies on the aerosol transmission of the pathogen in an open environment where biological markers—surrogates included—cannot be used.     

A stopped-flow study on the kinetics and mechanism of CO<Subscript>2</Subscript> uptake by chromium(III) complexes with histamine and pyridoxamine

The mechanism and kinetics of the reaction between an aqueous solution of CO₂ and coordinate ions, cis-[Cr(C₂O₄)(L–L)(OH₂)₂]⁺, where L–L denotes histamine (hm) or pyridoxamine (pm), were investigated using the stopped-flow technique. The studies were carried out at 5 to 25 °C over the pH range 6.04–8.15 at a fixed ionic strength solution (1 M NaClO₄). The results enabled determination of the number of steps of the reactions studied. Based on the kinetic equations, rate constants were determined for each step. Finally, thermodynamic activation parameter values H, were calculated for the reaction studied from temperature relationships.