Removal of Phenol from Wastewater Using Fenton-Like Reaction over Iron Oxide–Modified Silicates

Iron-containing active phase was deposited on natural layered silicate (vermiculite) using several techniques such as ion exchange, precipitation, and forced hydrolysis during hydrothermal digestion. Tuning of the synthesis conditions resulted in preparation of the catalysts with different loading of active phase and physicochemical properties. The composite materials were characterized with respect to their structure (X-ray diffraction), agglomeration state of Fe (diffuse reflectance UV-vis spectroscopy), and chemical composition. Catalytic tests were performed in semi-batch reactor under atmospheric pressure. Aqueous solution of phenol was used as a model industrial effluent, and hydrogen peroxide was added as an oxidant. Spectral techniques were used for identification of intermediate oxidation products. Spent catalysts were also characterized, and structural and chemical changes were determined, e.g., leaching degree of active phase

Replication of plasmids derived from Shiga toxinconverting bacteriophages in starved Escherichia coli

The pathogenicity of Shiga toxin-producing Escherichia coli (STEC) depends on the expression of stx genes that are located on lambdoid prophages. Effective toxin production occurs only after prophage induction, and one may presume that replication of the phage genome is important for an increase in the dosage of stx genes, positively influencing their expression. We investigated the replication of plasmids derived from Shiga toxin (Stx)-converting bacteriophages in starved E. coli cells, as starvation conditions may be common in the intestine of infected humans. We found that, unlike plasmids derived from bacteriophage lambda, the Shiga toxin phage-derived replicons did not replicate in amino acid-starved relA+ and relA” cells (showing the stringent and relaxed responses to starvation, respectively). The presence of the stable fraction of the replication initiator O protein was detected in all tested replicons. However, while ppGpp, the stringent response effector, inhibited the activities of the l PR promoter and its homologues from Shiga toxin-converting bacteriophages, these promoters, except for lambda PR, were only weakly stimulated by the DksA protein. We suggest that this less efficient (relative to lambda) positive regulation of transcription responsible for transcriptional activation of the origin contributes to the inhibition of DNA replication initiation of Shiga toxin-converting bacteriophages in starved host cells, even in the absence of ppGpp (as in starved relA” hosts). Possible clinical implications of these results are discussed

Differential inhibition of transcription from σ70- and σ32-dependent promoters by rifampicin

AbstractRifampicin is an antibiotic which binds to the β subunit of prokaryotic RNA polymerases and prevents initiation of transcription. It was found previously that production of heat shock proteins in Escherichia coli cells after a shift from 30°C to 43°C is not completely inhibited by this antibiotic. Here we demonstrate that while activity of a pL-lacZ fusion (pL is a σ70-dependent promoter) in E. coli cells is strongly inhibited by rifampicin, a pgroE-lacZ fusion, whose activity is dependent on the σ32 factor, retains significant residual activity even at relatively high rifampicin concentrations. Differential sensitivity to this antibiotic of RNA polymerase holoenzymes containing either the σ70 or the σ32 subunit was confirmed in vitro. Since the effects of an antibiotic that binds to the β subunit can be modulated by the presence of either the σ70 or the σ32 subunit in the holoenzyme, it is tempting to speculate that binding of various σ factors to the core of RNA polymerase results in different conformations of particular holoenzymes, including changes in the core enzyme

Contribution to knowledge of the mycobiota of "Bory Tucholskie" National Park (Northwestern Poland) : macromycetes of Central European lichen Scots pine forests of the Cladonio-Pinetum Juraszek 1927 type

This paper presents the results of mycological observations of the Cladonio- Pinetum community in the “Bory Tucholskie” National Park in 2018. Active protection treatments have been performed to protect disappearing communities. This study was conducted using the permanent circular plot method, with each plot having an area of approximately 100 m2. Observations were also carried out using the route method outside the plots. Consequently, 71 fungal taxa were found. Among the identified species of macromycetes are Boletopsis grisea, which is on the list of protected fungi, and seven species (Boletopsis grisea, Cortinarius armeniacus, Dacrymyces capitatus, Deconica montana, Entoloma rhodocalix, Tricholoma equestre, and Tricholoma colossus) that are on the red list of macrofungi in Poland

Selective catalytic oxidation (SCO) of ammonia to nitrogen over hydrotalcite originated Mg-Cu-Fe mixed metal oxides

Mg-Cu-Fe oxide systems, obtained from hydrotalcite-like precursors, were tested as catalysts for the selective catalytic oxidation (SCO) of ammonia. Copper containing catalysts were active in low-temperature SCO processes; however, their selectivity to nitrogen significantly decreased at higher temperatures. The optimum composition of the catalyst to guarantee high activity and selectivity to N2 was proposed. Temperature-programmed experiments, SCO catalytic tests performed with various contact times and additional tests on the samples in the selective catalytic reduction of NO with ammonia showed that the SCO process over the studied calcined hydrotalcites proceeds according to the internal SCR mechanism and oxidation of ammonia to NO is a rate-determining step in the low-temperature range

Genetic response to metabolic fluctuations: correlation between central carbon metabolism and DNA replication in Escherichia coli

BACKGROUND: Until now, the direct link between central carbon metabolism and DNA replication has been demonstrated only in Bacillus. subtilis. Therefore, we asked if this is a specific phenomenon, characteristic for this bacterium and perhaps for its close relatives, or a more general biological rule. RESULTS: We found that temperature-sensitivity of mutants in particular genes coding for replication proteins could be suppressed by deletions of certain genes coding for enzymes of the central carbon metabolism. Namely, the effects of dnaA46(ts) mutation could be suppressed by dysfunction of pta or ackA, effects of dnaB(ts) by dysfunction of pgi or pta, effects of dnaE486(ts) by dysfunction of tktB, effects of dnaG(ts) by dysfunction of gpmA, pta or ackA, and effects of dnaN159(ts) by dysfunction of pta or ackA. The observed suppression effects were not caused by a decrease in bacterial growth rate. CONCLUSIONS: The genetic correlation exists between central carbon metabolism and DNA replication in the model Gram-negative bacterium, E. coli. This link exists at the steps of initiation and elongation of DNA replication, indicating the important global correlation between metabolic status of the cell and the events leading to cell reproduction

Catalytic photodegradation of organic compounds using TiO2/pillared clays synthesized using a nonconventional aluminum source

This study evaluates the photocatalytic degradation of 2,6-dichlorophenol (2,6-DCP), triclosan (TCS) and bisphenol A (BPA) by ultraviolet (UV) and visible (VIS) light in the presence of TiO2/catalysts synthesized by wet impregnation followed by calcination. The catalyst supports used were three alumina pillared clays (Al-PILC) synthesized using various aluminum sources and montmorillonite (Mt) as raw material. One of the Al-PILC was prepared following the conventional method (Al-PILCCM), using a commercial aluminum salt, and the other two were synthesized using a saline slag, with the aluminum used being extracted with the alkaline (Al-PILCBE) or the acid (Al-PILCAE) method. Mt was impregnated with various amounts of titanium (1, 5, 10, and 20 wt% Ti) and evaluated for the photodegradation of the aforementioned pollutants, comparing the results with those obtained using commercial anatase. Due to the higher conversion rates, 10 and 20 wt% Ti were chosen to impregnate the Al-PILC and to evaluate the photocatalytic performance. All materials were characterized by several techniques, which confirmed the successful formation of TiO2 in the anatase phase. In all cases, photodegradation was higher when using UV light and the most photodegraded pollutant was TCS (85.15 ± 0.49%), followed by 2,6-DCP (65.43 ± 0.79%) and, to a lesser degree, BPA (36.15 ± 0.65%). Al-PILC showed higher photodegradation percentages, with Al-PILCAE exhibiting the highest values for both types of light. An analysis of the photoproducts by HPLC-MS suggested that the preferred pathway for TCS and 2,6-DCP photodegradation depends on the type of light used.The authors are grateful for financial support from the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033) through project PID2020-112656RB-C21. YC thanks the Universidad Pública de Navarra for a pre-doctoral grant (IberusTalent, European Union's H2020 research and innovation program under Marie Sklodowska-Curie grant agreement N° 801586). AG also thanks Banco Santander for funding via the Research Intensification Program

Incomplete degradation of lichen usnic acid and atranorin in Svalbard reindeer (Rangifer tarandus platyrhynchus)

Previous studies of Eurasian tundra reindeer (Rangifer tarandus tarandus) in Norway indicate that their rumen microbiota play a key role in degrading lichen secondary metabolites. We investigated the presence of usnic acid and atranorin in faecal samples from Svalbard reindeer (R. tarandus platyrhynchus). Samples were collected in Bolterdalen valley together with vegetation samples from the study site. The mesic tundra in this area was dominated by vascular plants (59% of vegetation cover). Bryophytes (16%) and lichens (25%) were also present. Qualitative and quantitative analyses of usnic acid and atranorin in lichen and faeces samples were performed using high-performance liquid chromatography. Contents of atranorin averaged 12.49 ± 0.41 mg g–1 in the thalli of Stereocaulon alpinum, while the average level of usnic acid was lowest in Cladonia mitis (12.75 ± 2.86 mg g–1) and highest in Flavocetraria cucullata (34.87 ± 0.47 mg g–1). Atranorin and usnic acid were detected in the faecal samples, averaging 0.41 ± 0.53 and 0.74 ± 1.11 (mean ± SD) mg g–1 dry matter, respectively. The presence of lichen secondary compounds in faeces from Svalbard reindeer shows that lichens are indeed included in their diet, although probably in small amounts because of depleted pastures. Contrary to previous findings in reindeer on mainland Norway, atranorin and usnic acid are not completely degraded or absorbed in Svalbard reindeer. To elucidate the mechanisms behind detoxification of lichen secondary compounds in reindeer, more research is needed on their respective rumen microbiomes and digestive enzymes

Data regarding particle size distribution, thermal properties and gaseous phase hydration of co-milled solid dispersions composed of tadalafil and Soluplus

A mechanical activation of the solid particles upon high-energy ball milling may considerably change the physicochemical properties of pharmaceutical compounds, including the morphology, particle size distribution, thermal properties, and surface interactions with water vapour upon gaseous phase hydration. Assessment of these changes is crucial for optimizing the manufacturing process of enabling drug products. In this article, we provide a detailed characterization of binary co-milled solid dispersions composed of tadalafil and Soluplus using a laser diffraction method, differential scanning calorimetry (DSC), gravimetric measurements and solid state (1)H- NMR spectroscopy. The data presented in this article is directly related to our previously published research article. They complement information on the impact that both formulation and process variables may have on the properties of these binary powder formulations