Synthesis of BiVO4/TiO2 composites and evaluation of their photocatalytic activity under indoor illumination

BiVO₄/TiO₂ composites with different weight ratios have been prepared by coprecipitation-based reactions followed by either thermal or hydrothermal treatment with the aim of evaluating the TiO₂ photosensitization by BiVO₄. The obtained materials present in all cases the desired monoclinic phase of BiVO₄ and anatase phase of TiO₂. Visible light absorption increased with increasing amount of bismuth vanadate. XPS results reveal the surface enrichment of Ti with respect to the bulk composition in samples characterised by a higher content of BiVO₄. The photocatalytic activity of the prepared materials was tested for the degradation of isopropanol in the gas phase under indoor illumination conditions. Although none of the composites was able to improve the activity of TiO₂, the low BiVO₄ containing samples appear as more suitable for further synthesis tuning.     

Antifungal activity of the pygidial gland secretion of <Emphasis Type="Italic">Laemostenus punctatus</Emphasis> (Coleoptera: Carabidae) against cave-dwelling micromycetes

The antifungal potential of the pygidial gland secretion of the troglophilic ground beetle Laemostenus punctatus from a cave in Southeastern Serbia against cave-dwelling micromycetes, isolated from the same habitat, has been investigated. Eleven collected samples were analyzed and 32 isolates of cave-dwelling fungi were documented. A total of 14 fungal species were identified as members of the genera Aspergillus, Penicillium, Alternaria, Cladosporium, Rhizopus, Trichoderma, Arthrinium, Aureobasidium, Epicoccum, Talaromyces, and Fusarium. Five isolates were selected for testing the antifungal activity of the pygidial gland secretion: Talaromyces duclauxi, Aspergillus brunneouniseriatus, Penicillium sp., Rhizopus stolonifer, and Trichoderma viride. The microdilution method has been applied to detect minimal inhibitory concentrations (MICs) and minimal fungicidal concentrations (MFCs). The most sensitive isolate was Penicillium sp., while the other isolates demonstrated a high level of resistance to the tested agent. L. punctatus has developed a special mechanism of producing specific compounds that act synergistically within the secretion mixture, which are responsible for the antifungal action against pathogens from the cave. The results open opportunities for further research in the field of ground beetle defense against pathogens, which could have an important application in human medicine, in addition to the environmental impact, primarily.     

Induction and reversion of multixenobiotic resistance in the marine snail Monodonta turbinata

Many marine organisms inherently express the presence and function of a new defence mechanism, termed multixenobiotic resistance mechanism (MXRM) because of its similarity to multidrug resistance (MDR) found in tumor cell lines resistant to chemotherapeutic drugs. However, previously no information was available on a possible induction of the activity of MXRM in organisms living at polluted sites. The purpose of the present study was to demonstrate the inducibility of this defence mechanism in the marine snail Monodonta turbinata, an organism known to inhabit a wide range of environmental conditions existing along a pollution gradient. Specimens of M. turbinata used in the present study were collected from March 1993 through March 1994 near Rovinj, Croatia. The accumulation of generally labelled ³H-vincristine (³H-VCR) in the gills of snails living at an unpolluted site was 67% higher and very sensitive to verapamil, an inhibitor of P-glycoprotein activity in comparison to snails living at a polluted site. The accumulation of vincristine (VCR) in snails from a polluted site was reduced and insensitive to verapamil due to the induced state of P-glycoprotein, as was demonstrated immunochemically by the enhanced concentration of a 140 kDa protein cross-reacting with the polyclonal antibodies raised against mammalian P-glycoprotein. MXRM could be induced in snails from the unpolluted site to the level found in snails living at a polluted site either by transplantation for 3 d to a polluted site, or by exposure for 3 d to sea water polluted with Diesel-2 oil (hydrocarbon concentration equivalent to 50 ppb of Kuwait oil). Discovery of the inducibility of this new defence mechanism in aquatic organisms may have important implications in ecotoxicology, as was demonstrated by a 104% enhanced accumulation of VCR in the presence of the MXRM-inhibitor, the so-called chemosensitizer. Besides, a striking difference in the levels of MXRM-elements (the sensitivity of the accumulation rate of xenobiotics to verapamil, immunochemical expression of P-glycoprotein, and the sensitivity of the binding of xenobiotics on membrane vesicles to verapamil) found between specimens living at the polluted and unpolluted sites offers a new molecular biomarker for exposure to pollutants.     

Metabolic fate of aromatic amines in the mussel Mytilus galloprovincialis

The postmitochondrial fraction of the digestive gland from the marine mussel Mytilus galloprovincialis possesses FAD-containing monooxygenase (EC 1.14.38) but lacks cytochrome P-450 dependent benzo(a)pyrene monooxygenase (EC 11.4.14.1). This is also evidenced by the ability of the mussel preparation to activate carcinogenic aromatic amines, but not carcinogenic benzo(a)pyrene, to Salmonella typhimurium TA 98 mutagens. This metabolic activity is NADPH dependent. Mussel digestive gland postmitochondrial fraction also possesses the enzymes needed for the detoxicating part of the aromatic amine metabolism: UDP-glucuronyl transferase (EC 2.4.1.17) and -glucuronidase (EC 3.2.1.31). Under the experimental conditions used here, this aromatic amine metabolic pathway converts up to 8% of 2-acetylamino(9-¹⁴C)fluorene, but not (G-³H)benzo(a)pyrene, to water soluble glucuronides. Glucuronic acid stimulates the formation of these glucuronides. The metabolites liberated from these glucuronides by the -glucuronidase treatment could be converted to TA 98 strain mutagens by the carp liver postmitochondrial fraction, but not by the mussel's digestive gland preparation. The presence of such a selective potential for the bioactivation and detoxication of aromatic amines, and not polycyclic aromatic hydrocarbons, in the marine invertebrate(s) may bring new insight to our understanding of the effects and the fate of carcinogens in the marine environment.     

Fostering collaboration between universities regarding regional sustainability initiatives – the University of Maribor

This paper presents the current position and role of the University of Maribor (UM) in linking stakeholders, in order to achieve sustainable regional development. A strategic approach is proposed for facilitating collaboration of the UM with regional development agencies, the local community and industry, based on collaborative learning and development. Furthermore, elements contributing to a successful learning partnership are identified together with the barriers. The results show that regional stakeholders (university, municipality, NGOs, and companies) are commonly engaged in a sustainable regional development, but their activities are not sufficiently linked. The strategic approach, and collaborative learning have led to many on-going SD projects within the University of Maribor. Room for improvement exists, regarding external university collaboration, especially in the fields of research, knowledge transfer, technological development, dissemination of information, education, and innovations.     

Fractionation and bioavailability of Cu in soil remediated by EDTA leaching and processed by earthworms (<Emphasis Type="Italic">Lumbricus terrestris</Emphasis> L.)

Background, aim, and scope  

Soil remediation with ethylenediamine tetraacetic acid (EDTA) leaching is capable of removing only part of the total metal concentration in the soil, mostly the labile, bioavailable metal species (metal bioavailability stripping). However, reintroduction of remediated soil in the environment exposes the soil to various environmental factors, which could potentially shift nonlabile residual metals back to labile bioavailable forms. We studied the effect of autochthonous earthworm species as model biotic environmental factor on the fractionation and bioavailability of Cu residual in soil after remediation.