One of the main mechanisms of nanoparticle toxicity is known to be the generation of reactive oxygen species (ROS) which primarily damage cell membranes. However, very limited data on membrane ...effects in anaerobic environments (where ROS could not be the cause of membrane damage) are available. In the following study, rumen anaerobe
Ruminococcus flavefaciens
007C was used as a bacterial model to assess the potential effects of Al
2
O
3
and TiO
2
nanoparticles on membranes in an anaerobic environment. Fatty acid profiles of cultures after exposure to Al
2
O
3
or TiO
2
nanoparticles were analyzed and compared with the profiles of non-exposed cultures or cultures exposed to bulk materials. Analysis revealed dose–effect changes in membrane composition exclusively when cells were exposed to Al
2
O
3
nanoparticles in a concentration range of 3–5 g/L, but were not present in cultures exposed to bulk material. On the other hand, the tested concentrations of nano-TiO
2
did not significantly affect the membrane profile of the exposed bacterium. The results suggest the possibility that Al
2
O
3
induces changes in bacterial membranes by direct physical interaction, which was supported by TEM image analysis.
Case studies of environmental impact assessment were performed for production steps of three traditional food production lines (dairy cow breeding, dry-cured ham, Brassica sp. growing) in order to ...examine the previously constructed methodological framework. The emission inventory was obtained on the basis of initial experimental data. The emissions were aggregated accordingly for the characterization to environmental impact categories. The contribution of studied process steps to several environmental impact categories was assessed (greenhouse gas emission, acidification potential, eutrophication potential, use of resources and use of agricultural land).
V tem prispevku predstavljamo končne rezultate ocenjevanja vplivov konkretnih primerov iz proizvodnih linij tradicionalnih živil na okolje. Na primerih uvajanja inovacij v proizvodnje linije v proizvodnji tradicionalnih živil (sir, pršut, cvetača) smo preverili ustreznost vnaprej vzpostavljenega metodološkega ogrodja za ocenjevanje vplivov na okolje. Na podlagi eksperimentalnih podatkov smo opravili popis emisij, iz popisa pa smo izračunali doprinos proizvodnih postopkov k posameznim kategorijam okoljskih vplivov. Glede na dostopnost in kakovost podatkov smo ocenili doprinos različnih postopkov pridelave k več kategorijam obremenjevanja okolja (izpusti toplogrednih plinov, prekurzorji kislega dežja, prekomerno kopičenje hranil v okolju, potencial za nastajanje ozonskih lukenj, raba kmetijskih površin in raba drugih virov).
Probiotiki so živi mikroorganizmi, ki zaužiti v ustreznem številu, ugodno vplivajo na zdravje gostitelja. Njihovi učinki so praviloma povezani z vzpostavitvijo ugodnega mikrobnega ravnovesja v ...prebavilih gostitelja ter uravnavanjem njegovega imunskega odziva. Pri domačih živalih so ključni učinki probiotikov povezani z izboljšano učinkovitostjo prireje. Poleg ugodnega vpliva na zdravstveno stanje (predvsem mladih) živali, slednje obsega tudi izboljšano konverzijo krme, povečano hitrost rasti in nekatere druge. Probiotični krmni dodatki registrirani v EU vsebujejo predvsem Gram-pozitivne bakterije iz rodov Bacillus, Enterococcus, Lactobacillus, Pediococcus, Streptococcus ter kvasovke Saccharomyces cerevisiae in Kluyveromyces sp. Medtem, ko je večina omenjenih mikroorganizmov načeloma varnih, imajo nekateri lastnosti, ki so lahko škodljive tako za živali, kot tudi za ljudi. Tak primer so enterokoki, pri katerih pogosto opažajo zapise za prenosljive determinante odpornosti proti antibiotikom. Slednji tako predstavljajo potencialno nevarnost za širjenje odpornosti v patogenih mikrobnih populacijah ljudi in živali. Hiter napredek na področju sintetične in sistemske biologije združen s podporo bioinformatike in novimi orodji genskega inženirstva v prihodnosti obeta skoraj neskončne možnosti za pripravo probiotičnih sevov s poljubnimi lastnostmi, vendar pa bodo le-ti lahko prestopili meje laboratorijev šele ob ustrezni spremembi zakonodaje in javnega mnenja.
In order to improve the knowledge on environmental impacts of current production systems and to find the solutions to reduce the negative impacts effective multi-approach environmental assessment ...methodologies are required. The environmental impacts assessed in complex systems, such as agriculture and food production, are prone to higher uncertainties. Therefore, field-specific standardization of the assessment procedures based on multiple screening studies are required to make the assessment outcome less vulnerable. The procedure array pairing for the formation of production step emission inventory is an important methodological process in environmental impact assessment. Initial production data was coupled with specialized databases, models found in scientific literature and environmental category characterization guidelines in order to construct an environmental impact methodological framework specific to four case studies of traditional food production.
Analiza okoljskih vplivov dejavnosti agroživilskega sektorja je večplastno opravilo, ki nas pogosto privede do precej negotovih ocen. Oceno vpliva na okolje, v kateri hkrati obravnavamo več vidikov obremenjevanja okolja, lahko izboljšamo s področno-specifično standardizacijo postopkov presoje, ki temelji na podlagi konkretnih primerov iz proizvodnje. Oblikovanje nabora postopkov za pripravo emisijske evidence posameznih proizvodnih korakov je pomemben proces ocenjevanja vplivov na okolje. V našem delu smo eksperimentalne in proizvodne podatke podprli s specializiranimi zbirkami podatkov, modeli iz strokovne literature ter smernicami za karakterizacijo okoljskih kategorij. Predstavljen metodološki okvir smo oblikovali za oceno okoljskega vpliva štirih primerov iz proizvodnje tradicionalnih živil.
Abstract
In order to study the effects of nanoparticles (NPs) with different physicochemical properties on cellular viability and structure, Saccharomyces cerevisiae were exposed to different ...concentrations of TiO2-NPs (1-3 nm), ZnO-NPs (<100 nm), CuO-NPs (<50 nm), their bulk forms, Ag-NPs (10 nm) and single-walled carbon nanotubes (SWCNTs). The GreenScreen assay was used to measure cyto- and genotoxicity, and transmission electron microscopy (TEM) used to assess ultrastructure. CuO-NPs were highly cytotoxic, reducing the cell density by 80% at 9 cm2/ml, and inducing lipid droplet formation. Cells exposed to Ag-NPs (19 cm2/ml) and TiO2-NPs (147 cm2/ml) contained dark deposits in intracellular vacuoles, the cell wall and vesicles, and reduced cell density (40 and 30%, respectively). ZnO-NPs (8 cm2/ml) caused an increase in the size of intracellular vacuoles, despite not being cytotoxic. SWCNTs did not cause cytotoxicity or significant alterations in ultrastructure, despite high oxidative potential. Two genotoxicity assays, GreenScreen and the comet assay, produced different results and the authors discuss the reasons for this discrepancy. Classical assays of toxicity may not be the most suitable for studying the effects of NPs in cellular systems, and the simultaneous assessment of other measures of the state of cells, such as TEM are highly recommended.
A total of 11 ruminal strains currently assigned to Butyrivibrio fibrisolvens and Pseudobutyrivibrio xylanivorans were cultivated in two different media, rumen fluid containing M2 and short-chain ...fatty acid (SCFA) containing M330, and their cellular fatty acid methyl esters (FAME) and dimethylacetals (DMA) were analyzed using gas chromatography. A comparison of the FAME/DMA compositions revealed that the difference in SCFA contents in the growth medium induced a pronounced quantitative effect on the cellular branched-chain fatty acid and aldehydes proportions only in the P. xylanivorans strains. This study shows that FAME/DMA analysis is a powerful chemotaxonomic tool in the group of phenotypically similar rumen butyrivibria especially when the influence of the growth medium is evaluated.
Evaluating the environmental impact of agricultural food production systems is a relatively recent research activity and the present methods for assessing the environmental impact associated with ...production-consumption systems are input-output accounting, ecological footprint analysis, life cycle assessment, financial evaluation of environmental externalities, farm cost and food miles. Complete environmental impact analyses require considerable amounts of data and time and are very likely to be expensive. Preliminary identification of the most-evident environmental hot spots is beneficial in aiding the determination of the analysis scope and goal and in setting the borders of the studied system. In the present study a reconstruction of the production schemes was performed and the identification of evident environmental impact hot spots was performed expert-wise for four selected model food products (hard cooked cheese, dry-cured ham, beer and cauliflower), traditional in Europe. This preliminary hot spot identification was preformed specifically for a conceptual life cycle assessment (LCA) technique in prosecution. In our opinion, these results can also be employed as a basis for many other environmental impact assessment approaches.
Abstract
We have studied the genotoxicity of TiO2 particles with a Comet assay on a unicellular organism, Tetrahymena thermophila. Exposure to bulk- or nano-TiO2 of free cells, cells embedded in gel ...or nuclei embedded in gel, all resulted in a positive Comet assay result but this outcome could not be confirmed by cytotoxicity measures such as lipid peroxidation, elevated reactive oxygen species or cell membrane composition. Published reports state that in the absence of cytotoxicity, nano- and bulk-TiO2 genotoxicity do not occur directly, and a possible explanation of our Comet assay results is that they are false positives resulting from post festum exposure interactions between particles and DNA. We suggest that before Comet assay is used for nanoparticle genotoxicity testing, evidence for the possibility of post festum exposure interactions should be considered. The acellular Comet test described in this report can be used for this purpose.
Case studies of environmental impact assessment were performed for production steps of three traditional food production lines (dairy cow breeding, dry-cured ham, Brassica sp. growing) in order to ...examine the previously constructed methodological framework. The emission inventory was obtained on the basis of initial experimental data. The emissions were aggregated accordingly for the characterization to environmental impact categories. The contribution of studied process steps to several environmental impact categories was assessed (greenhouse gas emission, acidification potential, eutrophication potential, use of resources and use of agricultural land).
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