1021. Preliminary study on vertical migrations of dinoflagellates in a dynamic coastal sea (Gulf of Trieste, northern Adriatic)Janja Francé, Patricija Mozetič, 2012, original scientific article Abstract: The purpose of this preliminary study was to define the vertical migration pattern in the dinoflagellate community in the shallow coastal sea. Migrations were followed in an area of mussel farming, through two 24-hour samplings, first during mixed and second during stratified water column conditions. Despite variable physical environment we were able to follow vertical migrations of some autotrophic dinoflagellate species in the period of stratified water column. The results also suggest that Heterocapsa sp. may preserve its vertical migration pattern also under mixed conditions. Migrations were observed also for Dinophysis sacculus that can cause DSP problems in the area.
Keywords: dinoflagellates, vertical migrations, eastern Adriatic coast, Adriatic Sea, dynamic environment, coastal sea, Adriatic
Published in DiRROS: 05.08.2024; Views: 433; Downloads: 129
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1022. Evaluation of metallothioneins in blue mussel (Mytilus galloprovincialis) as a biomarker of mercury and cadmium exposure in the Slovenian waters (Gulf of Trieste): a long-term field studyAndreja Ramšak, Janez Ščančar, Milena Horvat, 2012, original scientific article Abstract: In order to assess the spatial distribution and temporal trends of pollution with metals in the coastal sea of Slovenia, the level of metallothioneins (MT) was determined in blue mussels from three sampling locations, twice per year for a period of 10 years. MT concentrations ranged from 45 to 163 μg g-1 w.w. in March, and from 46 to 144 μg g-1 w.w. in the September sampling. The metals content was determined in whole mussel tissue once per year at two stations. The cadmium (Cd) concentration was in the range from 0.50 to 1.11 mg kg-1, while the concentration of mercury (Hg) was in the range from 0.70 to 0.237 mg kg-1. Results revealed no significant seasonal differences or differences between sampling sites in MT content, as well as variations in the content of Cd and Hg in mussels’ tissue during the examined period. The MT and metal content in mussels are not well correlated and other factors may have caused the fluctuations observed in MT content between years. This supports the notion that biomonitoring data have to be interpreted cautiously, taking into account various other factors that may influence MT induction.
Keywords: monitoring, coastal waters, biodiversity, bio-indicators, macrozoobenthos, metallothioneins, biocoenoses, ecological aspects, Gulf of Trieste
Published in DiRROS: 05.08.2024; Views: 884; Downloads: 166
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1023. Quantifying the intersexual and interspecific morphometric variation in two resembling sympatric lacertids : Iberolacerta horvathi and Podarcis muralisAnamarija Žagar, Nadja Osojnik, Miguel A. Carretero, Al Vrezec, 2012, original scientific article Abstract: Podarcis muralis and Iberolacerta horvathi are sympatric, frequently syntopic, lacertids through the entire range of I. horvathi and very similar in their general body size and shape, as well as in most ecological traits. We morphologically compared adults from the area of sympatry using biometric measurements and performed analyses to investigate their sexual size and shape dimorphism. A total of 34 males and 24 females of I. horvathi, and 25 males and 23 females of P. muralis, all adult individuals, were measured. Both species showed sexual size dimorphism with females being longer (snout-vent length, SVL) than males. After SVL correction (ANCOVA), head width, length and height and mass showed to be sexually dimorphic in both species. Males carry relatively wider, longer and higher heads and were heavier than conspecific females. I. horvathi heads were more flattened than those of P. muralis and P. muralis were heavier than I. horvathi. Both species displayed the same pattern of sexual dimorphism regarding body size, head size and shape not only in direction but also in magnitude. All results confirm that both species are very similar in studied biometric characters and, together with their ecological similarities, these suggest in absence of other factors they are likely to interact when living together.
Keywords: biometric characters, sexual dimorphism, southern Slovenia, Podarcis muralis, Iberolacerta horvathi, Lacertidae
Published in DiRROS: 05.08.2024; Views: 345; Downloads: 337
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1024. Reproductive biology, mating behavior, and vibratory communication of the brown-winged stink bug, Edessa meditabunda (Fabr.) (Heteroptera: Pentatomidae)Cleonor Cavalcante A. Silva, Raúl Alberto Laumann, Jonatas Barbosa Cavalcante Ferreira, Maria Carolina Blassioli Moraes, Miguel Borges, Andrej Čokl, 2012, original scientific article Abstract: We describe different aspects of the reproductive biology, mating behavior, and vibratory communication of the pentatomid Edessa meditabunda (Fabr.). This species shows lower copulation frequency and reproductive potential with longer sexual maturation period compared to other species of pentatomids. Females with multiple mating show increased fecundity when compared with single-mated females and both increased fecundity and reduced longevity when compared with virgin females. Courtship and mating behavior and vibratory signals are typical and similar to what was observed in other species of pentatomids, except that males started the courtship. These results constitute the first paper on biology, behavior, and vibratory communication among species of the subfamily Edessinae.
Keywords: animal ecology, animal communication
Published in DiRROS: 05.08.2024; Views: 486; Downloads: 322
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1025. Gene expression profiling of recombinant protein producing E. coli at suboptimal growth temperatureMitja Mahnič, Špela Baebler, Andrej Blejec, Špela Jalen, Kristina Gruden, Viktor Menart, Simona Jevševar, 2012, original scientific article Abstract: Recent studies have revealed that at lower cultivation temperatures (25 °C) much higher percentage of correctly folded recombinant hG-CSF protein can be extracted from inclusion bodies. Hence, the goal of our research was to investigate mechanisms determining characteristics of non-classical inclusion bodies production using gene expression profiling, focusing on proteases and chaperones gene expression. Statistical analysis of microarray data showed prominent changes in energy metabolism, in metabolism of amino acids and nucleotides, as well as in biosynthesis of cofactors and secondary metabolites if the culture was grown below its optimal temperature. Moreover, 24 differentially expressed up to now known genes classified among proteases, chaperones and other heat or stress related genes. Among chaperones UspE and among proteases YaeL and YeaZ might play an important role in accumulation of correctly folded recombinant proteins. Membrane localized protease yaeL gene was found to have higher activity at 25 °C and is thus potentially functionally related to the more efficient recombinant protein production at lower temperatures. The results of this study represent advance in the understanding of recombinant protein production in E. coli. Genes potentially influencing production of recombinant protein at lower growth temperature represent basis for further research towards improvement of E. coli production strains as well as fermentation process.
Keywords: recombinant protein production, non-classical inclusion bodies, expression microarrays, YaeL protease, GroEL chaperone
Published in DiRROS: 05.08.2024; Views: 498; Downloads: 396
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1026. Comparison and transfer testing of multiplex ligation detection methods for GM plantsGabriella Ujhelyi, Jeroen P. van Dijk, Theo W. Prins, Marleen Voorhuijzen, Angeline Van Hoef, Henriek G. Beenen, Dany Morisset, Kristina Gruden, Esther Kok, 2012, original scientific article Abstract: Background
With the increasing number of GMOs on the global market the maintenance of European GMO regulations is becoming more complex. For the analysis of a single food or feed sample it is necessary to assess the sample for the presence of many GMO-targets simultaneously at a sensitive level. Several methods have been published regarding DNA-based multidetection. Multiplex ligation detection methods have been described that use the same basic approach: i) hybridisation and ligation of specific probes, ii) amplification of the ligated probes and iii) detection and identification of the amplified products. Despite they all have this same basis, the published ligation methods differ radically. The present study investigated with real-time PCR whether these different ligation methods have any influence on the performance of the probes. Sensitivity and the specificity of the padlock probes (PLPs) with the ligation protocol with the best performance were also tested and the selected method was initially validated in a laboratory exchange study.
Results
Of the ligation protocols tested in this study, the best results were obtained with the PPLMD I and PPLMD II protocols and no consistent differences between these two protocols were observed. Both protocols are based on padlock probe ligation combined with microarray detection. Twenty PLPs were tested for specificity and the best probes were subjected to further evaluation. Up to 13 targets were detected specifically and simultaneously. During the interlaboratory exchange study similar results were achieved by the two participating institutes (NIB, Slovenia, and RIKILT, the Netherlands).
Conclusions
From the comparison of ligation protocols it can be concluded that two protocols perform equally well on the basis of the selected set of PLPs. Using the most ideal parameters the multiplicity of one of the methods was tested and 13 targets were successfully and specifically detected. In the interlaboratory exchange study it was shown that the selected method meets the 0.1% sensitivity criterion. The present study thus shows that specific and sensitive multidetection of GMO targets is now feasible.
Keywords: geneticallz modified organisms, GMO
Published in DiRROS: 05.08.2024; Views: 445; Downloads: 284
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1027. Vodne ptice in ujede Cerkniškega polja (Južna Slovenija) v letih 2007 in 2008, s pregledom zanimivejših opazovanj do konca leta 2010Dejan Bordjan, 2012, original scientific article Abstract: Od konca februarja 2007 do sredine februarja 2008 je bilo na Cerkniškem polju (južna Slovenija) v desetdnevnih obdobjih (dekadah) opravljenih 73 sistematičnih popisov vodnih ptic in ujed. Cilji raziskave so bili: ugotoviti številčnost in časovno dinamiko pojavljanja vrst, opredeliti njihov status, napraviti primerjavo s preteklim obdobjem sistematičnega zbiranja podatkov v letih 1991–1992, podati ocene gnezdečih, selitvenih in prezimujočih populacij ter na njihovi osnovi naravovarstveno ovrednotiti to območje. Zbrani so bili tudi drugi ornitološki podatki, pridobljeni do konca leta 2010. Med začetkom maja in začetkom septembra leta 2007 je voda na območju raziskave presahnila, tako da se je zadržala le v strugah potokov, vodna površina pa je bila deloma ali v celoti zaledenela od sredine novembra 2007 do začetka februarja 2008. Do konca leta 2010 je bilo na Cerkniškem polju skupaj zabeleženih 129 vrst vodnih ptic in ujed, v obdobju 2007/2008 pa 83. Dinamika pojavljanja vrst z več kot devetimi opazovanji je podrobneje predstavljena v pregledu vrst. Status gnezdilke ima 27 vrst, še nadaljnjih sedem pa je prehranskih gostov, ki gnezdijo v okolici območja raziskave. Največ vrst (118) ima status preletnega gosta, medtem ko je vrst s statusom poletnega (34) oziroma zimskega gosta (40) manj. Med zabeleženimi vrstami je 34 izjemnih in 21 redkih gostov. Prezimovalcev je 16, letovalcev sedem, vse leto pa se je tukaj zadrževalo šest vrst. V vseh dekadah obdobja raziskave so bile opažene štiri vrste: mlakarica Anas plathyrhynchos, siva čaplja Ardea cinerea, kanja Buteo buteo in postovka Falco tinnunculus. V več kot 90 % dekad je bila zabeležena še velika bela čaplja Ardea alba. Dve vrsti sta bili v obdobju 2007/2008 evdominantni (mlakarica 27,2 %, kanja 10,1 %), še dve pa dominantni (reglja Anas querquedula 7,4 %, liska Fulica atra 6,4 %). Največ osebkov je bilo zabeleženih konec marca in v začetku aprila (do 1978 os.), največ vrst (48) pa sredi aprila. Število vrst in osebkov je bilo med majem in avgustom zaradi presahlega jezera majhno. Najmanjše območje pojavljanja so imeli kormoran Phalacrocorax carbo ter skupina rac iz rodov Aythya, Bucephala in Mergellus. Galebi, čaplje, pobrežniki, lunji Circus sp. in rdečenoga postovka Falco vespertinus so se pojavljali na večjem delu območja raziskave. 10 gnezdilk izpolnjuje kriterije za oznako varstveno najpomembnejše vrste, od katerih sta dve (kostanjevka Aythya nyroca, veliki škurh Numenius arquata) vrsti globalne varstvene pozornosti, sedem pa vrste evropske varstvene pozornosti. Med negnezdilkami se 14 vrst vodnih ptic in ujed pojavlja v pomembnem številu (> 0,1 % biogeografske populacije), od tega se jih pet vsaj občasno pojavlja z več kot 1 % biogeografske populacije. Dve vrsti (rjavovrati ponirek Podiceps grisegena, kozica Gallinago gallinago) v Sloveniji gnezdita samo na Cerkniškem polju, še šest vrst pa ima tukaj vsaj 40 % slovenske gnezdeče populacije.
Keywords: vodne ptice, ujede, številčnost (biologija), dinamika pojavljanja (biologija), naravovarstveno vrednotenje
Published in DiRROS: 02.08.2024; Views: 382; Downloads: 230
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1028. In vitro corrosion-fatigue behaviour of rare-earth containing magnesium WE43 in sterile complex cell culture mediumJulia Nachtsheim, Songyun Ma, Jaka Burja, Alexander Köppl, Jan-Marten Seitz, Bernd Markert, 2024, original scientific article Abstract: Rare-earth containing magnesium alloys are promising biomedical materials for a new generation of biodegradable orthopaedic implant systems due to their excellent biocompatibility, mechanical and biodegradation properties. However, chemo-mechanical interactions in aggressive physiological corrosion environments result in rapid degradation and early loss of mechanical integrity, limiting its broader application for orthopaedic implants. To date, only few studies have assessed the corrosion-fatigue behaviour of medical-grade magnesium alloys in an organic physiological corrosion environment, especially under sterile test conditions. In the present work, the corrosion-fatigue behaviour of fine-grained medical-grade magnesium alloy WE43MEO was systematically analysed under in vitro conditions using an organic physiological fluid DMEM. The experimental results showed that the fatigue strength of the alloy is nearly unaffected by a 1-day precorrosion, while a 7-day precorrosion resulted in a significant deterioration of mechanical integrity. In corrosion-fatigue experiments, the fatigue life was considerably reduced by interactions between corrosion and fatigue damages. The SEM analysis revealed that the mixed mode of intergranular and transgranular fracture in the crack propagation zone transits to intergranular cracking dominant mode under the corrosion-fatigue conditions due to hydrogen embrittlement.
Keywords: corrosion-fatigue behaviour, stress corrosion mechanisms, biodegradable magnesium alloys, WE43, DMEM
Published in DiRROS: 02.08.2024; Views: 408; Downloads: 268
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1029. VEGF levels in plasma in relation to platelet activation, glycemic control, and microvascular complications in type 1 diabetesReinier O. Schlingemann, Cornelis J. F. van Noorden, Mattheus J.M. Diekman, Anna Tiller, Joost C.M. Meijers, Pieter Koolwijk, Wilmar M. Wiersinga, 2013, original scientific article Abstract: OBJECTIVE
Increased levels of vascular endothelial growth factor (VEGF) in human plasma samples have suggested that circulating VEGF is a cause of endothelial dysfunction in diabetes mellitus. However, artificial release of VEGF from platelets as a source of VEGF in plasma samples, as also occurs in serum samples, has not been ruled out in these studies.
RESEARCH DESIGN AND METHODS
We determined VEGF levels in plasma collected in both citrate and PECT, a medium that inactivates platelets, in a cross-sectional cohort of 21 healthy subjects and 64 patients with type 1 diabetes. In addition, we evaluated whether VEGF levels in both types of plasma correlated with the presence of diabetes, glycemic control, markers of in vivo or ex vivo platelet activation, and degree of diabetic retinopathy and nephropathy.
RESULTS
VEGF levels were invariably low in PECT plasma of both nondiabetic and diabetic subjects and were unrelated to any other diabetes-related variable studied. In contrast, VEGF levels in citrate plasma were 150% higher in diabetic patients than in control subjects and correlated with diabetes-related variables. Multiple linear regression analysis showed that levels of platelet factor 4, a marker for ex vivo platelet activation, and HbA1c were the independent predictors of VEGF levels in citrate plasma. Platelet activation, in vivo and ex vivo, was similar in diabetic persons and control subjects.
CONCLUSIONS
Like serum, citrate plasma is not suitable for reliable measurements of circulating VEGF. The low levels of VEGF in vivo, as represented by measurements in PECT plasma in our study, do not support a role of circulating VEGF in endothelial dysfunction in type 1 diabetes. Higher levels of VEGF in citrate plasma samples of diabetic persons do not represent the in vivo situation, but mainly originate from higher artificial ex vivo release from platelets correlating with the degree of glycemic control.
Keywords: vascular endothelial growth factor, VEGF, diabetes mellitus
Published in DiRROS: 02.08.2024; Views: 350; Downloads: 172
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1030. |
