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1521 - 1530 / 2000
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1521.
Polysaccharide-based bilayer coatings for biofilm-inhibiting surfaces of medical devices
Urban Ajdnik, Thomas Luxbacher, Alenka Vesel, Alja Štern, Bojana Žegura, Janja Trček, Lidija Fras Zemljič, 2021, original scientific article

Abstract: Chitosan (Chi) and 77KS, a lysine-derived surfactant, form polyelectrolyte complexes that reverse their charge from positive to negative at higher 77KS concentrations, forming aggregates that have been embedded with amoxicillin (AMOX). Dispersion of this complex was used to coat polydimethylsiloxane (PDMS) films, with an additional layer of anionic and hydrophilic hyaluronic acid (HA) as an outer adsorbate layer to enhance protein repulsion in addition to antimicrobial activity by forming a highly hydrated layer in combination with steric hindrance. The formed polysaccharide-based bilayer on PDMS was analyzed by water contact angle measurements, X-ray photoelectron spectroscopy (XPS), and surface zeta (ζ)-potential. All measurements show the existence and adhesion of the two layers on the PDMS surface. Part of this study was devoted to understanding the underlying protein adsorption phenomena and identifying the mechanisms associated with biofouling. Thus, the adsorption of a mixed-protein solution (bovine serum albumin, fibrinogen, γ-globulin) on PDMS surfaces was studied to test the antifouling properties. The adsorption experiments were performed using a quartz crystal microbalance with dissipation monitoring (QCM-D) and showed improved antifouling properties by these polysaccharide-based bilayer coatings compared to a reference or for only one layer, i.e., the complex. This proves the benefit of a second hyaluronic acid layer. Microbiological and biocompatibility tests were also performed on real samples, i.e., silicone discs, showing the perspective of the prepared bilayer coating for medical devices such as prostheses, catheters (balloon angioplasty, intravascular), delivery systems (sheaths, implants), and stents.
Keywords: polysaccharides, chitosan, hyaluronic acid, anti-biofilm, silicone
Published in DiRROS: 19.07.2024; Views: 495; Downloads: 229
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1522.
Succinylation of polyallylamine: influence on biological efficacy and the formation of electrospun fibers
Lucija Jurko, Matej Bračič, Silvo Hribernik, Damjan Makuc, Janez Plavec, Filip Jerenec, Sonja Žabkar, Nenad Gubeljak, Alja Štern, Rupert Kargl, 2021, original scientific article

Abstract: Succinylation of proteins is a commonly encountered reaction in biology and introduces negatively charged carboxylates on previously basic primary amine groups of amino acid residues. In analogy, this work investigates the succinylation of primary amines of the synthetic polyelectrolyte polyallylamine (PAA). It investigates the influence of the degree of succinylation on the cytotoxicity and antibacterial activity of the resulting polymers. Succinylation was performed in water with varying amounts of succinic anhydride and at different pH values. The PAA derivatives were analyzed in detail with respect to molecular structure using nuclear magnetic resonance and infrared absorbance spectroscopy. Polyelectrolyte and potentiometric charge titrations were used to elucidate charge ratios between primary amines and carboxylates in the polymers. The obtained materials were then evaluated with respect to their minimum inhibitory concentration against Staphylococcus aureus and Pseudomonas aeruginosa. The biocompatibility was assessed using mouse L929 fibroblasts. The degree of succinylation decreased cytotoxicity but more significantly reduced antibacterial efficacy, demonstrating the sensitivity of the fibroblast cells against this type of ampholytic polyelectrolytes. The obtained polymers were finally electrospun into microfiber webs in combination with neutral water-soluble polyvinyl alcohol. The resulting non-woven could have the potential to be used as wound dressing materials or coatings.
Keywords: polyallylamine hydrochloride, succinylation, aqueous chemistry, cytotoxicity, antimicrobial effect, electrospinning, nanofibers, mouse L929 fibroblasts, Staphylococcus aureus, Pseudomonas aeruginosa
Published in DiRROS: 19.07.2024; Views: 307; Downloads: 286
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1523.
Single-use plastic bans pollution : exploring stakeholder perspectives on best practices for reducing plastic
Emily Cowan, Andy M. Booth, Andreas Misund, Katja Klun, Ana Rotter, Rachel Tiller, 2021, original scientific article

Abstract: Abstract In this study, we conducted and documented workshops and interviews in Norway and Slovenia to identify stakeholder and future generation opinions and mitigation strategies for solving one of the most prominent environmental issues: plastic pollution. As part of the EU H2020 project GoJelly, stakeholders were brought together to explore their perceptions on considering jellyfish mucus as a new resource to contribute to reducing plastic pollution from entering the marine environment. The study was conducted in the spring of 2019, in a context directly after the European Union (EU) announced its Directive to ban the most commonly used single-use plastic (SUP) items. The study applied the snowball method as a methodological choice to identify relevant stakeholders. Systems thinking was utilized as a participatory modelling approach, which allowed for the creation of conceptual mind maps from the various workshops and interviews, to understand consumers’ consciousness, and to map out ideas on plastic pollution reduction. Plastic pollution takes place on a global scale and stakeholders discussed their individual perceptions of national and international solutions that could be put in place to solve it, including the opportunities around utilizing jellyfish mucus to filter and capture micro- and nanoplastic. We found that industry stakeholders in both case areas were generally more accepting of policy and increased innovation moving forward, but placed weight on the scientific community to conduct more research on the pollution issue and propose solutions. Future generation stakeholders (youth aged 14–18), however, put emphasis on consumer behavior and buying patterns of single-use products fueling the plastic crisis.
Keywords: ecology, plastics, single-use plastic, stakeholder integration, plastic pollution, systems thinking
Published in DiRROS: 19.07.2024; Views: 404; Downloads: 212
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1524.
Grass growth and ▫$N_2O$▫ emissions from soil after application of jellyfish in coastal areas
Florian Borchert, Iraj Emadodin, Christof Kluß, Ana Rotter, Thorsten Reinsch, 2021, original scientific article

Abstract: The supply of nutrients for agricultural production faces enormous challenges as food security and sustainability goals have to be ensured. Processing of marine biomass has high potential to provide nutrients for agricultural purposes in coastal areas. One underexplored resource are jellyfish, which occur as blooms and by-catch of the fishing industry. In this context, a pot experiment investigated the effects of jellyfish as a fertilizer on biomass accumulation of annual ryegrass (Lolium multiflorum), and its effect on the important greenhouse gas N2O as a sustainability indicator of novel fertilizers. Dried and ground jellyfish was applied [3 species: Aurelia aurita (AA), Cyanea capillata (CC), Periphylla periphylla (PP)] and compared with an unfertilized and a mineral fertilized (calcium-ammonium-nitrate, CAN) treatment. Dried jellyfish and CAN were applied at equal N rates of 5 g N per m2. The N2O-fluxes from soil were measured over 56 days after fertilizer application. Grass dry matter yields, when using CC and PP treatments, were not significantly different to the CAN treatment (p > 0.05). After reducing its salinity, AA also showed no differences to CAN on plant growth and the lowest coefficient of variation for dry matter yield as an indicator for yield stability. Accumulated N2O-emissions were lowest in the control and were 3-times higher in AA and CC compared to CAN (p < 0.05). If salinity levels are moderate, jellyfish application to soil can compete with artificial mineral fertilizers in terms of N-supply for above- and belowground yield response, regardless of jellyfish species used. However, elevated N2O-emissions are likely to affect its suitability for large-scale application. Nevertheless, if energy-efficient methods of drying and desalination of jellyfish can be developed, in coastal areas dried jellyfish is a valuable fertilizer in coastal areas, particularly in situations where nutrient supplies for agriculture are limited.
Published in DiRROS: 19.07.2024; Views: 337; Downloads: 218
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1525.
Biochemical and functional characterization of mutant KRAS epitopes validates this oncoprotein for immunological targeting.
Adham S. Bear, Tatiana Blanchardt, Joseph Cesare, Michael J. Ford, Lee P. Richman, Chong Xu, Miren L. Baroja, Sarah McCuaig, Christina Costeas, Khatuna Gabunia, John Scholler, Avery D. Posey, Mark H. OʹHara, Anže Smole, Daniel J. Powell, Benjamin A. Garcia, Robert H. Vonderheide, Gerald P. Linette, Beatriz M Carreno, 2021, original scientific article

Abstract: Activating RAS missense mutations are among the most prevalent genomic alterations observed in human cancers and drive oncogenesis in the three most lethal tumor types. Emerging evidence suggests mutant KRAS (mKRAS) may be targeted immunologically, but mKRAS epitopes remain poorly defined. Here we employ a multi-omics approach to characterize HLA class I-restricted mKRAS epitopes. We provide proteomic evidence of mKRAS epitope processing and presentation by high prevalence HLA class I alleles. Select epitopes are immunogenic enabling mKRAS-specific TCRαβ isolation. TCR transfer to primary CD8+ T cells confers cytotoxicity against mKRAS tumor cell lines independent of histologic origin, and the kinetics of lytic activity correlates with mKRAS peptide-HLA class I complex abundance. Adoptive transfer of mKRAS-TCR engineered CD8+ T cells leads to tumor eradication in a xenograft model of metastatic lung cancer. This study validates mKRAS peptides as bona fide epitopes facilitating the development of immune therapies targeting this oncoprotein.
Published in DiRROS: 19.07.2024; Views: 313; Downloads: 213
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1526.
Sequestration of polystyrene microplastics by jellyfish mucus
Živa Lengar, Katja Klun, Iztok Dogša, Ana Rotter, David Stopar, 2021, original scientific article

Abstract: The worldwide microplastics pollution is a serious environmental and health problem that is currently not effectively mitigated. In this work we tested jellyfish mucus as a new bioflocculent material capable of sequestration of polystyrene microplastics in aqueous environments. Mucus material was collected from different jellyfish species and was used to trap fluorescently tagged polystyrene microspheres. The efficiency of removal was tested using varying concentrations of microplastics and mucus. The interaction between the microplastics and mucus was determined by viscosity measurements and confocal laser scanning microscopy. Different mucus preparation methods were also tested: freshly prepared, mechanically sheared, freeze-thawed, freeze-dried, and hydrolyzed mucus. The results demonstrate that jellyfish mucus can efficiently sequester polystyrene microplastics particles from the suspension. The fraction of the removed microplastics was highest with freshly prepared mucus and decreased with freeze-thawing and freeze-drying. The mucus ability to sequester microplastics was completely lost in the hydrolyzed mucus. The results imply that the intact jellyfish mucus has the potential to be used as a biopolymer capable of removing microplastics material.
Published in DiRROS: 19.07.2024; Views: 327; Downloads: 231
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1527.
Comparison of in-situ chlorophyll-a time series and sentinel-3 ocean and land color instrument data in Slovenian national waters (Gulf of Trieste, Adriatic Sea)
El Khalil Cherif, Patricija Mozetič, Janja Francé, Vesna Flander-Putrle, Jana Faganeli Pucer, Martin Vodopivec, 2021, original scientific article

Abstract: While satellite remote sensing of ocean color is a viable tool for estimating large-scale patterns of chlorophyll-a (Chl-a) and global ocean primary production, its application in coastal waters is limited by the complex optical properties. An exploratory study was conducted in the Gulf of Trieste (Adriatic Sea) to assess the usefulness of Sentinel-3 satellite data in the Slovenian national waters. OLCI (Ocean and Land Colour Instrument) Chl-a level 2 products (OC4Me and NN) were compared to monthly Chl-a in-situ measurements at fixed sites from 2017 to 2019. In addition, eight other methods for estimating Chl-a concentration based on reflectance in different spectral bands were tested (OC3M, OC4E, MedOC4, ADOC4, AD4, 3B-OLCI, 2B-OLCI and G2B). For some of these methods, calibration was performed on in-situ data to achieve a better agreement. Finally, L1-regularized regression and random forest were trained on the available dataset to test the capabilities of the machine learning approach. The results show rather poor performance of the two originally available products. The same is true for the other eight methods and the fits to the measured values also show only marginal improvement. The best results are obtained with the blue-green methods (OC3, OC4 and AD4), especially the AD4SI (a designated fit of AD4) with R = 0.56 and RMSE = 0.4 mg/m³, while the near infrared (NIR) methods show underwhelming performance. The machine learning approach can only explain 30% of the variability and the RMSE is of the same order as for the blue-green methods. We conclude that due to the low Chl-a concentration and the moderate turbidity of the seawater, the reflectance provided by the Sentinel-3 OLCI spectrometer carries little information about Chl-a in the Slovenian national waters within the Gulf of Trieste and is therefore of limited use for our purposes. This requires that we continue to improve satellite products for use in those marine waters that have not yet proven suitable. In this way, satellite data could be effectively integrated into a comprehensive network that would allow a reliable assessment of ecological status, taking into account environmental regulations.
Keywords: hydrobiology, coastal waters, Gulf of Trieste, chlorophyll-a, Sentinel-3, OLCI, machine learning
Published in DiRROS: 19.07.2024; Views: 379; Downloads: 697
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1528.
The pathogens spillover and incidence correlation in bumblebees and honeybees in Slovenia
Metka Pislak, Ivan Toplak, Urška Zajc, Danilo Bevk, 2021, original scientific article

Abstract: Slovenia has a long tradition of beekeeping and a high density of honeybee colonies, but less is known about bumblebees and their pathogens. Therefore, a study was conducted to define the incidence and prevalence of pathogens in bumblebees and to determine whether there are links between infections in bumblebees and honeybees. In 2017 and 2018, clinically healthy workers of bumblebees (Bombus spp.) and honeybees (Apis mellifera) were collected on flowers at four different locations in Slovenia. In addition, bumblebee queens were also collected in 2018. Several pathogens were detected in the bumblebee workers using PCR and RT-PCR methods: 8.8% on acute bee paralysis virus (ABPV), 58.5% on black queen cell virus (BQCV), 6.8% on deformed wing virus (DWV), 24.5% on sacbrood bee virus (SBV), 15.6% on Lake Sinai virus (LSV), 16.3% on Nosema bombi, 8.2% on Nosema ceranae, 15.0% on Apicystis bombi and 17.0% on Crithidia bombi. In bumblebee queens, only the presence of BQCV, A. bombi and C. bombi was detected with 73.3, 26.3 and 33.3% positive samples, respectively. This study confirmed that several pathogens are regularly detected in both bumblebees and honeybees. Further studies on the pathogen transmission routes are required.
Published in DiRROS: 19.07.2024; Views: 322; Downloads: 166
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1529.
A review of constraints and solutions for collecting raptor samples and contextual data for a European Raptor Biomonitoring Facility
Maria Dulsat-Masvidal, Rui Lorenço, Silvia Lacorte, Tamer Albayarak, Marcello DʹAmico, Jovan Andevski, Al Vrezec, Arianna Aradis, Emanuel Baltag, Oded Berger-Tal, 2021, original scientific article

Abstract: The COST Action ‘European Raptor Biomonitoring Facility’ (ERBFacility) aims to develop pan-European raptor biomonitoring in support of better chemicals management in Europe, using raptors as sentinel species. This presents a significant challenge involving a range of constraints that must be identified and addressed. The aims of this study were to: (1) carry out a comprehensive review of the constraints that may limit the gathering in the field of raptor samples and contextual data, and assess their relative importance across Europe; and (2) identify and discuss possible solutions to the key constraints that were identified. We applied a participatory approach to identify constraints and to discuss feasible solutions. Thirty-one constraints were identified, which were divided into four categories: legal, methodological, spatial coverage, and skills constraints. To assess the importance of the constraints and their possible solutions, we collected information through scientific workshops and by distributing a questionnaire to stakeholders in all the countries involved in ERBFacility. We obtained 74 answers to the questionnaire, from 24 of the 39 COST participating countries. The most important constraints identified were related to the collection of complex contextual data about sources of contamination, and the low number of existing raptor population national/regional monitoring schemes and ecological studies that could provide raptor samples. Legal constraints, such as permits to allow the collection of invasive samples, and skills constraints, such as the lack of expertise to practice necropsies, were also highlighted. Here, we present solutions for all the constraints identified, thus suggesting the feasibility of establishing a long-term European Raptor Sampling Programme as a key element of the planned European Raptor Biomonitoring Facility.
Published in DiRROS: 19.07.2024; Views: 386; Downloads: 307
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1530.
Systems toxicology approach for assessing developmental neurotoxicity in Larval zebrafish
Roman Li, Marja Talikka, Vincenzo Belcastro, Colette vom Berg, Florian Martin, Manuel C. Peitsch, Julia Hoeng, Anže Županič, 2021, original scientific article

Abstract: Adverse outcomes that result from chemical toxicity are rarely caused by dysregulation of individual proteins; rather, they are often caused by system-level perturbations in networks of molecular events. To fully understand the mechanisms of toxicity, it is necessary to recognize the interactions of molecules, pathways, and biological processes within these networks. The developing brain is a prime example of an extremely complex network, which makes developmental neurotoxicity one of the most challenging areas in toxicology. We have developed a systems toxicology method that uses a computable biological network to represent molecular interactions in the developing brain of zebrafish larvae. The network is curated from scientific literature and describes interactions between biological processes, signaling pathways, and adverse outcomes associated with neurotoxicity. This allows us to identify important signaling hubs, pathway interactions, and emergent adverse outcomes, providing a more complete understanding of neurotoxicity. Here, we describe the construction of a zebrafish developmental neurotoxicity network and its validation by integration with publicly available neurotoxicity-related transcriptomic datasets. Our network analysis identified consistent regulation of tumor suppressors p53 and retinoblastoma 1 (Rb1) as well as the oncogene Krüppel-like factor (Klf8) in response to chemically induced developmental neurotoxicity. The developed network can be used to interpret transcriptomic data in a neurotoxicological context.
Published in DiRROS: 19.07.2024; Views: 311; Downloads: 200
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