731. Double strand breaks and cell-cycle arrest induced by the cyanobacterial toxin cylindrospermopsin in HepG2 cellsAlja Štern, Metka Filipič, Matjaž Novak, Bojana Žegura, 2013, original scientific article Abstract: The newly emerging cyanobacterial cytotoxin cylindrospermopsin (CYN) is increasingly found in surface freshwaters, worldwide. It poses a potential threat to humans after chronic exposure as it was shown to be genotoxic in a range of test systems and is potentially carcinogenic. However, the mechanisms of CYN toxicity and genotoxicity are not well understood. In the present study CYN induced formation of DNA double strand breaks (DSBs), after prolonged exposure (72 h), in human hepatoma cells, HepG2. CYN (0.1–0.5 µg/mL, 24–96 h) induced morphological changes and reduced cell viability in a dose and time dependent manner. No significant increase in lactate dehydrogenase (LDH) leakage could be observed after CYN exposure, indicating that the reduction in cell number was due to decreased cell proliferation and not due to cytotoxicity. This was confirmed by imunocytochemical analysis of the cell-proliferation marker Ki67. Analysis of the cell-cycle using flow-cytometry showed that CYN has an impact on the cell cycle, indicating G0/G1 arrest after 24 h and S-phase arrest after longer exposure (72 and 96 h). Our results provide new evidence that CYN is a direct acting genotoxin, causing DSBs, and these facts need to be considered in the human health risk assessment.
Keywords: cylindrospermopsin, cell-cycle, cell-proliferation, double-strand breaks, HepG2 cells
Published in DiRROS: 02.08.2024; Views: 313; Downloads: 224
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732. APS8, a polymeric alkylpyridinium salt blocks [alpha]7 nAChR and induces apoptosis in non-small cell lung carcinomaAna Zovko, Kristina Viktorsson, Rolf Lewensohn, Katja Kološa, Metka Filipič, Hong Xing, William R. Kem, Laura Paleari, Tom Turk, 2013, original scientific article Abstract: Naturally occurring 3-alkylpyridinium polymers (poly-APS) from the marine sponge Reniera sarai, consisting of monomers containing polar pyridinium and nonpolar alkyl chain moieties, have been demonstrated to exert a wide range of biological activities, including a selective cytotoxicity against non-small cell lung cancer (NSCLC) cells. APS8, an analog of poly-APS with defined alkyl chain length and molecular size, non-competitively inhibits α7 nicotinic acetylcholine receptors (nAChRs) at nanomolar concentrations that are too low to be acetylcholinesterase (AChE) inhibitory or generally cytotoxic. In the present study we show that APS8 inhibits NSCLC tumor cell growth and activates apoptotic pathways. APS8 was not toxic for normal lung fibroblasts. Furthermore, in NSCLC cells, APS8 reduced the adverse anti-apoptotic, proliferative effects of nicotine. Our results suggest that APS8 or similar compounds might be considered as lead compounds to develop antitumor therapeutic agents for at least certain types of lung cancer.
Keywords: 3-alkylpyridinium polymers, apoptosis, nicotine, nicotinic acetylcholine receptor, non-small cell lung carcinoma
Published in DiRROS: 02.08.2024; Views: 257; Downloads: 208
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733. Exceptional dense water formation on the Adriatic shelf in the winter of 2012Hrvoje Mihanović, Ivica Vilibić, Sandro Carniel, M. Tudor, A. Russo, A. Bergamasco, N. Bubić, Z. Ljubešić, Damir Viličić, A. Boldrin, Vlado Malačič, Massimo Celio, Cinzia Comici, F. Raicich, 2013, original scientific article Abstract: In this paper we document dense water formation throughout the Adriatic shelf and coastal area in January/February 2012, resulting in record-breaking densities observed during and after the event. The unprecedented dense water generation was preconditioned by a dry and warm year which resulted in a significant reduction of coastal freshwaters, superimposed on a long-term basin-wide salinity increase. The final event that triggered the dense water formation was an extended period of cold weather with strong and severe winds. Record-breaking potential density anomalies (above 30 kg m−3) were measured at several formation sites. Accumulated surface net heat and water losses in some coastal regions exceeded 1.5 GJ m−2 and 250 kg m−2 over 21 days, respectively. Excessiveness, importance of shelf-type dense water formation and effects on the thermohaline circulation and deep aquatic systems are discussed.
Keywords: sea, marine water, density, physical oceanography, dense water, water density, Adriatic sea, Mediterranean sea, Adriatic shelf
Published in DiRROS: 02.08.2024; Views: 314; Downloads: 266
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734. Structural and functional responses of harpacticoid copepods to anoxia in the Northern Adriatic: an experimental approachMarleen Roelofs, Marleen De Troch, Bettina Riedel, Mateja Grego, 2013, original scientific article Abstract: Combined in situ and laboratory studies were conducted to document the effects of anoxia on the structure and functioning of meiobenthic communities, with special focus on harpacticoid copepods. In a first step, anoxia was created artificially by means of an underwater chamber at 24 m depth in the Northern Adriatic, Gulf of Trieste (Mediterranean). Nematodes were found as the most abundant taxon, followed by harpacticoid copepods. While nematode densities were not affected by treatment (anoxia/normoxia) or sediment depth, these factors had a significant impact on copepod abundances. Harpacticoid copepod family diversity, in contrast, was not affected by anoxic conditions, only by depth. Ectinosomatidae and Cletodidae were most abundant in both normoxic and anoxic samples.
The functional response of harpacticoid copepods to anoxia was studied in a laboratory tracer experiment by adding 13C pre-labelled diatoms to sediment cores in order to test (1) if there is a difference in food uptake by copepods under normoxic and anoxic conditions and (2) whether initial (normoxia) feeding of harpacticoid copepods on diatoms results in a better survival of copepods in subsequent anoxic conditions. Independent of the addition of diatoms, there was a higher survival rate in normoxia than anoxia. The supply of additional food did not result in a higher survival rate of copepods in anoxia, which might be explained by the presence of a nutritionally better food source and/or a lack of starvation before adding the diatoms. However, there was a reduced grazing pressure by copepods on diatoms in anoxic conditions. This resulted in a modified fatty acid composition of the sediment. We concluded that anoxia not only impacts the survival of consumers (direct effect) but also of primary producers (indirect effect), with important implications for the recovery phase.
Keywords: morje, plankton, kopepodi, živalski plankton, trofični status, morski plankton, harpaktikoidi, anoksije
Published in DiRROS: 02.08.2024; Views: 276; Downloads: 240
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735. CellTracker Green labelling vs. Rose Bengal staining: CTG wins by points in distinguishing living from dead anoxia-impacted copepods and nematodsMateja Grego, Michael Stachowitsch, Marleen De Troch, Bettina Riedel, 2013, original scientific article Abstract: Hypoxia and anoxia have become a key threat to shallow coastal seas. Much is known about their impact on macrofauna, less on meiofauna. In an attempt to shed more light on the latter group, in particular from a process-oriented view, we experimentally induced short-term anoxia (1 week) in the northern Adriatic Sea (Mediterranean) and examined the two most abundant meiofauna taxa – harpacticoid copepods and nematodes. Both taxa also represent different ends of the tolerance spectrum, with copepods being the most sensitive and nematodes among the most tolerant. We compared two methods: CellTracker Green (CTG) – new labelling approach for meiofauna – with the traditional rose bengal (RB) staining method. CTG binds to active enzymes and therefore colours live organisms only. The two methods show considerable differences in the number of living and dead individuals of both meiofauna taxa. Generally, RB will stain dead but not yet decomposed copepods and nematodes equally as it does live ones. Specifically, RB significantly overestimated the number of living copepods in all sediment layers in anoxic samples, but not in any normoxic samples. In contrast, for nematodes, the methods did not show such a clear difference between anoxia and normoxia. RB overestimated the number of living nematodes in the top sediment layer of normoxic samples, which implies an overestimation of the overall live nematofauna. For monitoring and biodiversity studies, the RB method might be sufficient, but for more precise quantification of community degradation, especially after an oxygen depletion event, CTG labelling is a better tool. Moreover, it clearly highlights the surviving species within the copepod or nematode community. As already accepted for foraminiferal research, we demonstrate that the CTG labelling is also valid for other meiofauna groups.
Keywords: morje, plankton, kopepodi, živalski plankton, trofični status, morski plankton, CTG, CellTracker Green
Published in DiRROS: 02.08.2024; Views: 284; Downloads: 204
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736. Vloga matičnih celic pri napredovanju in zdravljenju gliomaUrška Verbovšek, Tamara Lah Turnšek, Helena Motaln, Mateja Robič, 2013, original scientific article Abstract: Izvor tumorjev in stohastično naravo procesa karcinogeneze najbolje opisuje hierarhični model, ki predvideva obstoj tumorskih matičnih celic (TMC). Slednje predstavljajo populacijo celic z neomejenim samoobnovitvenim potencialom, ki so se sposobne diferencirati v vrste celic vseh treh zarodnih linij in so manj občutljive na večino protirakavih učinkovin. Zato predstavljajo glavni vir za razvoj in rast tumorja, zaradi svoje odpornosti na kemoterapijo pa so vzrok za ponovitev bolezni. Za uspešno zdravljenje možganskega tumorja glioma in njegove najbolj maligne oblike, glioblastoma multiformae (GBM), bi zato bilo potrebno odstraniti prav vse TMC. Žal slednjega zaradi prehitre infiltrativne vrasti subpopulacije GBM celic z visoko izraženimi geni za gibljivost (migratom) v okolno zdravo možgansko tkivo, ni možno doseči s trenutno uporabljanimi načini zdravljenja (npr. kirurškim izrezom)
Poleg TMC, ki so ključne za razvoj in razrast tumorja, tkivo tumorja vsebuje še hematopoetske matične celice, endotelne predniške celice in mezenhimske matične celice (MMC). Delovanje teh drugih vrst matičnih celic, kjer je bila celicam MMC že dokazana protitumorska aktivnost v GBM, pa je odvisno od tumorskega mikrookolja. Žal mehanizmi in delovanje MMC med modulacijo rasti tumorja preko parakrinih in neposrednih interakcij z GBM (matičnimi) celicami še niso znani. Kljub temu pa matične celice, s poudarkom na MMC, predstavljajo nove nosilce npr. za ciljni vnos terapevtske učinkovine v tumor, ki bi lahko izboljšali učinkovitost trenutnih protitumorskih terapij. Razvoj celičnih zdravil veliko obeta, saj so MMC, poleg svojih imunomodulacijskih lastnosti, sposobne tudi usmerjenega gibanja v GBM in tam učinkovati, o čemer razpravlja ta prispevek.
Keywords: tumorske matične celice, mezenhimske matične celice, mikrookolje tumorja, celična terapija
Published in DiRROS: 02.08.2024; Views: 470; Downloads: 184
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737. Identification of plasma biomarker candidates in glioblastoma using an antibody-array-based proteomic approachKlemen Zupančič, Marjan Koršič, Urška Verbovšek, Primož Rožman, Tamara Lah Turnšek, Andrej Blejec, Kristina Gruden, Helena Motaln, Miomir Knežević, Matija Veber, Ana Herman, 2014, original scientific article Abstract: Background. Glioblastoma multiforme (GBM) is a brain tumour with a very high patient mortality rate, with a median survival of 47 weeks. This might be improved by the identification of novel diagnostic, prognostic and predictive
therapy-response biomarkers, preferentially through the monitoring of the patient blood. The aim of this study was to define the impact of GBM in terms of alterations of the plasma protein levels in these patients.
Materials and methods. We used a commercially available antibody array that includes 656 antibodies to analyse
blood plasma samples from 17 healthy volunteers in comparison with 17 blood plasma samples from patients with
GBM.
Results. We identified 11 plasma proteins that are statistically most strongly associated with the presence of GBM.
These proteins belong to three functional signalling pathways: T-cell signalling and immune responses; cell adhesion and migration; and cell-cycle control and apoptosis. Thus, we can consider this identified set of proteins as potential diagnostic biomarker candidates for GBM. In addition, a set of 16 plasma proteins were significantly associated with the overall survival of these patients with GBM. Guanine nucleotide binding protein alpha (GNAO1) was associated with both GBM presence and survival of patients with GBM.
Conclusions. Antibody array analysis represents a useful tool for the screening of plasma samples for potential cancer biomarker candidates in small-scale exploratory experiments; however, clinical validation of these candidates requires their further evaluation in a larger study on an independent cohort of patients.
Keywords: glioblastoma, proteomics, biomarker
Published in DiRROS: 02.08.2024; Views: 297; Downloads: 231
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738. New records of opistobranch gastropods in the waters off Slovenia (Gulf of Trieste, Northern Adriatic Sea)Lovrenc Lipej, Borut Mavrič, Jan Simič, Domen Trkov, 2014, original scientific article Abstract: The paper deals with four opisthobranch molluscs, which were found in the Slovenian marine waters as new records. The pleurobranchomorph Pleurobranchea meckeli was found on two occasions on muddy detritic bottom in the Gulf of Piran in June of 2013 and 2014. The nudibranch Favorinus branchialis was found in May and June 2014 on turf vegetation in a very shallow area off the pier in Koper harbour. Its spawn with white eggs was also found nearby. The second nudibranch Facelina rubrovittata was found in March 2010 crawling in the intertidal zone of the Nature reserve Strunjan. The third nudibranch Dondice banyulensis was found in waters of the Nature Monument Debeli rtic on sedimentary bottom. With the fi nding of these four species, the total number of opisthobranchs recorded to date in the Slovenian part of the Adriatic Sea increased to 75 species.
Keywords: opistobranch fauna, sea, Slovenia, Mediterranean Sea, Gulf of Trieste
Published in DiRROS: 02.08.2024; Views: 306; Downloads: 140
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739. The lesser-known medusa Drymonema dalmatinum Haeckel 1880 (Scyphozoa, Discomedusae) in the Adriatic SeaAlenka Malej, Martin Vodopivec, Davor Lučić, Ivona Onofri, Branka Pestorić, 2014, original scientific article Abstract: Authors report historical and recent records of the little-known medusa Drymonema dalmatinum in the Adriatic
Sea. This large scyphomedusa, which may develop a bell diameter of more than 1 m, was fi rst described in 1880 by
Haeckel based on four specimens collected near the Dalmatian island Hvar. The paucity of this species records since
its description confi rms its rarity, however, in the last 15 years sightings of D. dalmatinum have been more frequent.
Keywords: scyphomedusae, historical occurrence, recent observations, Adriatic Sea
Published in DiRROS: 02.08.2024; Views: 301; Downloads: 121
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740. Recurrence of Sargassum vulgare C. Agardh in Slovenian coastal waters (Adriatic Sea)Martina Orlando-Bonaca, Borut Mavrič, 2014, original scientific article Abstract: Perennial species from the genus Sargassum are considered to be indicators of high environmental quality and are therefore used in the assessment of the Ecological Status of Mediterranean coastal waters according to the European Water Framework Directive (WFD, 2000/60/EC). Over the past three decades a signifi cant decline in Sargassum populations has been reported in the Gulf of Trieste, as well as in other Adriatic and Mediterranean areas. In Slovenian coastal waters the presence of Sargassum spp. had not been confi rmed since 1980, after a severe decline due to overgrazing by the sea urchin Paracentrotus lividus. Recently, however, some thalli of S. vulgare were found in Piran Bay. The recurrence of this species is discussed in the paper, as well as the possible causes that led to the non-recovery in its populations in last decades in Slovenian coastal waters.
Keywords: macroalgae, Gulf of Trieste, Sargassum, Mediterranean Sea, non-recovery of populations
Published in DiRROS: 02.08.2024; Views: 278; Downloads: 148
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