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Povzetek: V letu 2011 smo izvedli monitoring 17 izbranih vrst ptic na 20 IBA. Identificirali smo naslednje grožnje za ptice na IBA: 1. lov, katerega posledica sta vznemirjanje in nenamerni odstrel (kostanjevka) 2. elektroudar (velika uharica) 3. vznemirjanje na gnezdiščih zaradi rekreacije (velika uharica) 4. intenzifikacija kmetijstva – premena ekstenzivnih travnikov v intenzivne travnike, njive, pašnike; komasacije z odstranjevanjem drevesnih mejic in nekošenih pasov, manjšanje površine visokodebelnih sadovnjakov (zlatovranka, kosec, črnočeli srakoper, hribski škrjanec, veliki skovik itd.) 5. neustrezen vodni režim na gnezdišču (navadna čigra, kostanjevka) 6. uničevanje pomembnih elementov za gnezdenje in prehranjevanje: odstranitev kolonij (navadna čigra), požiganje trstičja in druge obvodne vegetacije (grahasta tukalica, kostanjevka), odstranjevanje grmišč in mejic (črnočeli srakoper, hribski škrjanec, veliki skovik), sekanje primernih gnezditvenih in prehranjevalnih dreves (triprsti in srednji detel) 7. gradbeni in energetski projekti (vrtni strnad) 8. pomlajevanje gozdnih sestojev z neprimernimi ali alohtonimi drevesnimi vrstami (smreka in zeleni bor v Krakovskem gozdu) (srednji detel + ostale kvalifikacijske vrste tega IBA)
Objavljeno v DiRROS: 16.09.2024; Ogledov: 653; Prenosov: 647
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Povzetek: Wood is considered a promising raw material for the circular bioeconomy and has the ability to store biogenic carbon, and this is one reason why we want to extend the service life of the wood. In order to consider the influence of durability in our study, we used two wood species with different lifespans. Beech (Fagus sylvatica L.) belongs to the group of very sensitive wood species, as the durability of the untreated wood is estimated to be around 5 years; meanwhile, pine (Pinus sylvestris L.) belongs to the group of moderately resistant wood species, where the durability of the untreated wood is estimated to be up to 15 years. While toxic chemicals are often used for wood preservation, hydroxyapatite offers an environmentally friendly solution for wood mineralization. This study presents life cycle assessment (LCA) and life cycle cost (LCC) analyses comparing a novel hydroxyapatite (HAp) mineralization method with a service life of 50 years to a non-mineralized reference alternative. LCA was based on EN ISO 14040 and EN ISO 14044, while LCC was adapted from the European Commission’s LCC tool for public procurement. The results of the LCA show that mineralized wood has a lower overall impact on the environment than surface-treated beech wood but a higher impact than surface-treated pine wood. Most impact categories were determined by electricity consumption with the exception of stratospheric ozone depletion, water consumption, and land use. Water consumption proved to be the category where the mineralization process was problematic due to water consumption during the leaching process. The LCC showed that mineralized wood is the most cost-effective solution for the exterior façade, as all costs, but especially investment costs, were lower. The differences in the LCA and LCC results are mainly due to the different lifetimes of the two alternatives. It can be concluded that if energy-intensive processes and chemicals are used in the production of the material, the extended lifetime must be sufficient to account for the additional impacts that occur during the production phase.
Ključne besede: environmental impacts, hydroxyapatite, life cycle assessment (LCA), life cycle cost analysis (LCC), wood mineralization
Objavljeno v DiRROS: 09.09.2024; Ogledov: 136; Prenosov: 2518
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Povzetek: Water can be an important source of plant pathogenic viruses. Usually they are present in low concentrations, but environmental waters still represent a potential pathway for virus transmission. Already over 30 years ago, plant viruses have been shown to be present in environmental waters in considerable amounts (Koenig, 1986). Since then, many questions concerning the origin, survival, and spread of plant viruses by water have been raised, especially in the light of increased irrigation and use of hydroponic systems in agriculture (Mehle and Ravnikar 2012). The majority of the plant pathogenic viruses recovered from environmental waters so far are very stable. They can infect plants via the roots without the aid of a vector and often have a wide host range (Mehle and Ravnikar 2012). The release of such viruses from plants can lead to their diffusion in streams, rivers and lakes, thereby ensuring the long-distance spread of viruses that would otherwise remain restricted to limited areas (Mehle et al., 2014; Mehle and Ravnikar, 2012).
Objavljeno v DiRROS: 03.09.2024; Ogledov: 136; Prenosov: 51
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Povzetek: Recombinant adeno-associated viruses (rAAVs) play a pivotal role in the treatment of genetic diseases. However, current production and purification processes yield AAV-based preparations that often contain unwanted empty, partially filled or damaged viral particles and impurities, including residual host cell DNA and proteins, plasmid DNA, and viral aggregates. To precisely understand the composition of AAV preparations, we systematically compared four different single-stranded AAV (ssAAV) and self-complementary (scAAV) fractions extracted from the CsCl ultracentrifugation gradient using established methods (transduction efficiency, analytical ultracentrifugation (AUC), quantitative and digital droplet PCR (qPCR and ddPCR), transmission electron microscopy (TEM) and enzyme-linked immunosorbent assay (ELISA)) alongside newer techniques (multiplex ddPCR, multi-angle light-scattering coupled to size-exclusion chromatography (SEC-MALS), multi-angle dynamic light scattering (MADLS), and high-throughput sequencing (HTS)). Suboptimal particle separation within the fractions resulted in unexpectedly similar infectivity levels. No single technique could simultaneously provide comprehensive insights in the presence of both bioactive particles and contaminants. Notably, multiplex ddPCR revealed distinct vector genome fragmentation patterns, differing between ssAAV and scAAV. This highlights the urgent need for innovative analytical and production approaches to optimize AAV vector production and enhance therapeutic outcomes.
Ključne besede: recombinant adeno-associated viruses (rAAVs), CsCl ultracentrifugation gradient, analytical methods, digital droplet PCR (ddPCR), transmission electron microscopy (TEM), analytical ultracentrifugation (AUC), size-exclusion chromatography coupled with multi-angle light scattering (SEC-MALS), Illumina sequencing, virology
Objavljeno v DiRROS: 07.08.2024; Ogledov: 215; Prenosov: 235
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Povzetek: Background Erythromycin is a medically important antibiotic, biosynthesized by the actinomycete Saccharopolyspora erythraea. Genes encoding erythromycin biosynthesis are organized in a gene cluster, spanning over 60 kbp of DNA. Most often, gene clusters encoding biosynthesis of secondary metabolites contain regulatory genes. In contrast, the erythromycin gene cluster does not contain regulatory genes and regulation of its biosynthesis has therefore remained poorly understood, which has for a long time limited genetic engineering approaches for erythromycin yield improvement. Results We used a comparative proteomic approach to screen for potential regulatory proteins involved in erythromycin biosynthesis. We have identified a putative regulatory protein SACE_5599 which shows significantly higher levels of expression in an erythromycin high-producing strain, compared to the wild type S. erythraea strain. SACE_5599 is a member of an uncharacterized family of putative regulatory genes, located in several actinomycete biosynthetic gene clusters. Importantly, increased expression of SACE_5599 was observed in the complex fermentation medium and at controlled bioprocess conditions, simulating a high-yield industrial fermentation process in the bioreactor. Inactivation of SACE_5599 in the high-producing strain significantly reduced erythromycin yield, in addition to drastically decreasing sporulation intensity of the SACE_5599-inactivated strains when cultivated on ABSM4 agar medium. In contrast, constitutive overexpression of SACE_5599 in the wild type NRRL23338 strain resulted in an increase of erythromycin yield by 32%. Similar yield increase was also observed when we overexpressed the bldD gene, a previously identified regulator of erythromycin biosynthesis, thereby for the first time revealing its potential for improving erythromycin biosynthesis. Conclusions SACE_5599 is the second putative regulatory gene to be identified in S. erythraea which has positive influence on erythromycin yield. Like bldD, SACE_5599 is involved in morphological development of S. erythraea, suggesting a very close relationship between secondary metabolite biosynthesis and morphological differentiation in this organism. While the mode of action of SACE_5599 remains to be elucidated, the manipulation of this gene clearly shows potential for improvement of erythromycin production in S. erythraea in industrial setting. We have also demonstrated the applicability of the comparative proteomics approach for identifying new regulatory elements involved in biosynthesis of secondary metabolites in industrial conditions.
Ključne besede: erythromycin, polyketide, regulator, SACE_5599, lmbU, differentiation (biology), sporulation, strain improvement, metabolic engineering
Objavljeno v DiRROS: 02.08.2024; Ogledov: 184; Prenosov: 201
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