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Ergosterol, a precursor of vitamin D2, is present in the cell membrane of all fungi. It can be transformed into vitamin D2 by UV-B exposure. In this study, a basidiomycete, Pleurotus sapidus, cultivated in liquid malt extract medium was exposed to UV-B light. In addition, autoclaved, abiotic mycelium was put through UV-B exposure for the first time. The effects of different UV-B exposure times, surface areas and temperatures on vitamin D2 formation were analyzed. The conversion of ergosterol to vitamin D2 at ambient temperature almost reached completion within 10 min resulting in vitamin D2 concentrations of 365 µg (g dry matter)−1. Prolonged exposure of the biotic mycelium for up to 60 min resulted in a reduced vitamin D2 concentration with stagnation at about 280 µg (g dry matter)−1. Exposure of the abiotic mycelium showed a slower increase but also leveled off at the same concentration. Furthermore, it could be shown that vitamin D2 formation depends on the temperature and the exposed surface area. The vitamin D2 concentration augmented after increasing the exposed surface from 65.0 to 298.6 cm2. The ergosterol content of P. sapidus was analyzed in a way similar to vitamin D2 and resulted in 3.75 ± 0.06 mg (g dry matter)−1 ergosterol. [ABSTRACT FROM AUTHOR]

Purpose: To conceptualize the journey that veterinary antibiotics (VAs) follow between the animal stall and the field, two experiments were conducted. (1) The VAs sulfadiazine, sulfamethazine, sulfamethoxazole and tetracycline were mixed into cow excrement; prepared with three dry solid content variations. (2) Cow excrement containing the same VAs was mixed into sandy and clayey saturated soils. The aim was to quantify the solid-liquid partitioning and time-dependent behaviour of VAs at each stage of the journey, to enable mathematical replication of the process in the future. Materials and methods: In each case, the mixtures were partitioned into their solid and liquid phases and the VA concentration in each was determined using liquid chromatography tandem mass spectrometry. Sorption isotherms ( K values) and elimination constants ( k: solid form, k: liquid form) were calculated after various incubation periods. Results and discussion: Sulfamethoxazole exhibits fast elimination in excrement; environmental contamination is unlikely. Sulfadiazine and sulfamethazine behave similarly in excrement and soils; tetracycline is more sorptive. Small percentages of the sulfadiazine, sulfamethazine and tetracycline masses initially found in excrement may subsequently be transported to environmental compartments in liquid form. However, the majority of these VAs are speculated to accumulate in soil or be transported to surface water systems via soil erosion. Conclusions: The VA journey has been mathematically conceptualized for the first time and is supported by sorption isotherms and eliminations constants for four commonly detected VAs. Critical findings for sulfadiazine, sulfamethazine and tetracycline are (1) the majority of an initial VA mass resides in excrement liquid; (2) following incorporation into soil, the majority of the same initial VA mass resides in soil solid; (3) VAs found in soil liquid are assumed to be eliminated within a few months; (4) VAs found in soil solid are assumed to persist and accumulate; and (5) VAs are most likely to be transported to surface water systems in solid form (via soil erosion). Due to its rapid elimination in excrement, sulfamethoxazole that stems from veterinary medicine is not assumed to be a major environmental contaminant. [ABSTRACT FROM AUTHOR]

Pharmaceuticals are widely distributed in low concentrations in the water compartment. Conventional sewage treatment plants (STP) are not capable to remove pharmaceuticals to the full extent, so alternative methods such as ozonization or photooxidation are tested as additional stage. However, it has been shown that in many cases no complete mineralization is achieved during these processes and transformation products occur. Up to now only little is known about these transformation products in terms of their structure and toxicity. The antibiotic sulfathiazole (STZ) is used in veterinary medicine and it can be detected in different water matrices such as STP effluent or surface water. We tested the ability of photooxidation for degradation of STZ using a medium pressure mercury lamp. LC-UV showed the formation of several minor compounds and one main transformation product which has been isolated subsequently. Using NMR and high resolution mass spectrometry techniques, we were able to reveal the structure of promizole, an antituberculotic, used in the 1950s. This compound showed a reduced microbial activity in Brilliant Black Reduction Maximum Residue Level test. Furthermore, there was no difference in the effects of promizole when compared to STZ on cell toxicity and cell proliferation in two murine cell lines. [ABSTRACT FROM AUTHOR]