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23. Molecular screening for cyanobacteria and their cyanotoxin potential in diverse habitatsMaša Jablonska, Tina Eleršek, Polona Kogovšek, Sara Skok, Andreea Oarga-Mulec, Janez Mulec, 2024, izvirni znanstveni članek Povzetek: Cyanobacteria are adaptable and dominant organisms that exist in many harsh and extreme environments due to their great ecological tolerance. They produce various secondary metabolites, including cyanotoxins. While cyanobacteria are well studied in surface waters and some aerial habitats, numerous other habitats and niches remain underexplored. We collected 61 samples of: (i) biofilms from springs, (ii) aerial microbial mats from buildings and subaerial mats from caves, and (iii) water from borehole wells, caves, alkaline, saline, sulphidic, thermal, and iron springs, rivers, seas, and melted cave ice from five countries (Croatia, Georgia, Italy, Serbia, and Slovenia). We used (q)PCR to detect cyanobacteria (phycocyanin intergenic spacer—PC-IGS and cyanobacteria-specific 16S rRNA gene) and cyanotoxin genes (microcystins—mcyE, saxitoxins—sxtA, cylindrospermopsins—cyrJ), as well as amplicon sequencing and morphological observations for taxonomic identification. Cyanobacteria were detected in samples from caves, a saline spring, and an alkaline spring. While mcyE or sxtA genes were not observed in any sample, cyrJ results showed the presence of a potential cylindrospermopsin producer in a biofilm from a sulphidic spring in Slovenia. This study contributes to our understanding of cyanobacteria occurrence in diverse habitats, including rare and extreme ones, and provides relevant methodological considerations for future research in such environments. Ključne besede: extreme environments, cylindrospermopsin, sulphidic springs, caves, qPCR, PC-IGS Objavljeno v DiRROS: 05.08.2024; Ogledov: 208; Prenosov: 140 Celotno besedilo (1,09 MB) Gradivo ima več datotek! Več... |
24. Adjusting the operational potential window as a tool for prolonging the durability of carbon-supported Pt-alloy nanoparticles as oxygen reduction reaction electrocatalystsTina Đukić, Leonard Moriau, Iva Klofutar, Martin Šala, Luka Pavko, Francisco Javier Gonzalez Lopez, Francisco Ruiz-Zepeda, Andraž Pavlišič, Miha Hotko, Matija Gatalo, Nejc Hodnik, 2024, izvirni znanstveni članek Objavljeno v DiRROS: 05.08.2024; Ogledov: 230; Prenosov: 164 Celotno besedilo (1,99 MB) Gradivo ima več datotek! Več... |
25. The epiplankton community in the southern Adriatic: multiple trophic levels along the south - north and inshore-offshore gradientsValentina Turk, Davor Lučić, Jakica Njire, Senka Terzić, Tinkara Tinta, Adam Benović, Alenka Malej, 2012, izvirni znanstveni članek Povzetek: The epiplankton community was investigated during Meduza cruises along south - north and offshore – inshore transects in the middle and southern Adriatic in spring 2002. The diel and vertical distribution of heterotrophic bacteria, phytoplankton pigment composition, micro- and mesozooplankton were assessed. At most stations we observed a thermocline at approximately 20 m and a prominent chlorophyll a peak at about 70 m depth. The integrated phytoplankton and bacterial biomass were lower at the station in the central part of the southern Adriatic, and increased gradually towards middle Adriatic and towards coastal stations. Vertical profiles of both bacterial abundance and production showed a distinct peak in the surface layer. Bacterial abundance was high also in the layer of the deep chlorophyll a maximum. Higher bacterial production was associated with elevated abundance of pico- and nanoplankton feeding zooplankton indicating that bacterial populations were generally controlled by predation. Ključne besede: Meduza project, heterotrophic bacteria, Adriatic Sea, South Adriatic Sea, phytoplankton pigments, open sea, microzooplankton, mesozooplankton, research cruises Objavljeno v DiRROS: 05.08.2024; Ogledov: 219; Prenosov: 107 Celotno besedilo (584,09 KB) Gradivo ima več datotek! Več... |
26. Seasonal variation in marine-snow-associated and ambient-water prokaryotic communities in the northern Adriatic SeaJana Vojvoda, Dominique Lamy, Eva Sintes, Juan A.L. Garcia, Valentina Turk, Gerhard J. Herndl, 2014, izvirni znanstveni članek Povzetek: The structure and activity of prokaryotic communities were determined in marine snow and in the ambient water of the northern Adriatic Sea in different seasons (autumn, spring and summer). The seasonal variation in the composition of marine-snow-associated and ambient-water bacterial communities was assessed by T-RFLP (Terminal Restriction Fragment Length Polymorphism) on the 16S rRNA gene (16S rDNA) and 16S rRNA transcript (16S rRNA) level. On the 16S rDNA level, the bacterial community composition of the marine snow and ambient water was similar in summer and autumn, but not in spring. In contrast, on the 16S rRNA level, indicative of the active bacterial community, the marine-snow-associated bacterial community was different from that of the ambient-water, and different from the bacterial community on the 16S rDNA level, except in autumn. To phylogenetically characterize the bacterial and archaeal community composition associated with marine snow and the ambient water, clone libraries of 16S rDNA and 16S rRNA were constructed from 2 contrasting seasons. Phylogenetic profiling revealed a higher similarity among bacterial communities in summer compared to late autumn. Certain bacterial and archaeal groups were exclusively associated with summer or autumn marine snow, suggesting that marine-snow-associated prokaryotic communities are subjected to successional changes similar to ambient-water communities. Moreover, the presence of bacterial groups enriched in marine snow including Vibrionales and sulphate-reducing bacteria is consistent with niche partitioning and metabolic adaptations of the particle-associated microbiota. Ključne besede: marine snow, free-living-bacteria, Northern Adriatic sea Objavljeno v DiRROS: 02.08.2024; Ogledov: 218; Prenosov: 109 Celotno besedilo (387,65 KB) Gradivo ima več datotek! Več... |
27. Mixtures of Chemical Pollutants at European Legislation Safety Concentrations: How Safe are They?Raquel Negrão Carvalho, Augustine Aruqwe, Selim Ait-Aissa, Anne Bado-Nilles, Stefania Balzamo, Anders Baun, Shimshon Belkin, Ludek Blaha, Francois Brion, Daniela Conti, Vesna Flander-Putrle, Valentina Turk, 2014, izvirni znanstveni članek Povzetek: The risk posed by complex chemical mixtures in the environment to wildlife and humans is increasingly debated, but has been rarely tested under environmentally relevant scenarios. To address this issue, two mixtures of 14 or 19 substances of concern (pesticides, pharmaceuticals, heavy metals, polyaromatic hydrocarbons, a surfactant, and a plasticizer), each present at its safety limit concentration imposed by the European legislation, were prepared and tested for their toxic effects. The effects of the mixtures were assessed in 35 bioassays, based on 11 organisms representing different trophic levels. A consortium of 16 laboratories was involved in performing the bioassays. The mixtures elicited quantifiable toxic effects on some of the test systems employed, including i) changes in marine microbial composition, ii) microalgae toxicity, iii) immobilization in the crustacean Daphnia magna, iv) fish embryo toxicity, v) impaired frog embryo development, and vi) increased expression on oxidative stress-linked reporter genes. Estrogenic activity close to regulatory safety limit concentrations was uncovered by receptor-binding assays. The results highlight the need of precautionary actions on the assessment of chemical mixtures even in cases where individual toxicants are present at seemingly harmless concentrations. Ključne besede: morje, analizna kemija, biologija, evtrofikacija, hranilne snovi, fitoplankton, onesnaževanje, Piranski zaliv Objavljeno v DiRROS: 02.08.2024; Ogledov: 220; Prenosov: 212 Celotno besedilo (4,50 MB) Gradivo ima več datotek! Več... |
28. Combined use of chlorophyll a and phycocyanin fluorescence sensors for quantification and differentiation of phytoplankton : a useful approach for small surface water bodiesTinkara Rozina, Tina Eleršek, Maja Zupančič Justin, Andrej Meglič, 2018, izvirni znanstveni članek Povzetek: Sensors based on in vivo measurements of photosynthetic pigments fluorescence enable real-time phytoplankton monitoring with high spatial and temporal resolution. A combination of chlorophyll a (CHL) and phycocyanin (PC) fluorescence sensors was used for phytoplankton quantification and differentiation in two small water bodies, Koseze Pond and pond in Hotinja vas. The high correlation of CHL and PC fluorescence signals with biovolume was confirmed during the two-year monitoring in anatural pond environment in spite of a seasonal succession of the phytoplankton. Additionally, disturbances of the sensors were investigated. Water bodies containing predominantly algae yielded false positive signals of the PC sensor, which reached up to 1% of the intensity of the CHL signal. Similarly, underestimated counts of cyanobacteria measured with CHL fluorescence sensor can be adjusted using PC fluorescence sensor. Ključne besede: small water bodies, algae, cyanobacteria, fluorescence sensors, biovolume Objavljeno v DiRROS: 01.08.2024; Ogledov: 187; Prenosov: 130 Celotno besedilo (699,64 KB) Gradivo ima več datotek! Več... |
29. "Only introduced" or "invasive" : spread of the alga Aulacoseira ambigua f. japonica from Asia to Africa and EuropeTina Eleršek, 2018, izvirni znanstveni članek Povzetek: Many non-native algal species are found in waters all over the world. Many terms are used to describe such organisms that have expanded their distribution. However, a unified model or concept remains to be defined, as how biological ‘invasions’ are seen depends on the perspective. Understanding invasive organisms is important for biodiversity, science policy and water management. During monitoring sampling at Slivniško Lake (Slovenia) in 2016, the curved diatom Aulacoseira ambigua f. japonica Tuji & D.M. Williams was identified. This species originates from Japan, from where it was described more than 100 years ago. The chronology of the published distributions of A. ambigua f. japonica defines its spread from Japan to Asia, then to western Russia and South Africa, and now to central Europe. This study provides further evidence that A. ambigua f. japonica has become established in Europe (Slovenia), as supported by light microscopy and scanning electron microscopy. To the best of our knowledge, this is the first qualitative and quantitative description of A. ambigua f. japonica in Europe. It has been suggested that the shape of these algal colonies is significant for the interpretation of ecological information, and indeed, also in the present case, spiral colonies were found in this eutrophic water body. Although curved cells and colonies can also be interpreted as (sub)populations or morphological variants, only detailed molecular studies can reveal if these also have taxonomic significance. Ključne besede: algae, introduced species, invasive species, scanning electron microscopy Objavljeno v DiRROS: 01.08.2024; Ogledov: 222; Prenosov: 192 Celotno besedilo (2,56 MB) Gradivo ima več datotek! Več... |
30. Extraction of DNA from different sample types - a practical approach for GMO testingJana Žel, Tina Demšar, Dejan Štebih, Mojca Milavec, Kristina Gruden, 2015, izvirni znanstveni članek Povzetek: Current methods based on DNA targets for the detection, identification and quantification of genetically modified organisms (GMOs) involve extraction of the DNA. Different extraction procedures have been developed for the great variety of samples from food, feed, seeds and particular plant parts. This makes the operation of routine analytical laboratories complex and workloads heavy. Here we present a decision-making system, developed over many years of GMO testing on different samples, that result in the application of only a few extraction methods for the majority of samples. Developed decision-making system enables quicker and more cost effective testing of GMOs. In addition, the performance of DNA extraction resulting from the use of the selected extraction methods is presented for use in subsequent testing of GMOs by real time PCR methods. This approach can be used as a model for similar systems based on nucleic acid analysis in food, feed, seeds and plants. Ključne besede: extraction methods, genetically modified organisms, GMO, decision- making system (biology), GMO testing, cetyltrimethylammonium bromide, CTAB Objavljeno v DiRROS: 29.07.2024; Ogledov: 187; Prenosov: 130 Celotno besedilo (793,24 KB) Gradivo ima več datotek! Več... |