Sirvi Kuupäev , alustades "2020-06" järgi

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Pronominaalsete viitesuhete automaatne lahendamine eesti keeles närvivõrkude abil
(Tartu Ülikool, 2020-06) Freienthal, Linda; Muischnek, Kadri, juhendaja; Tartu Ülikool. Humanitaarteaduste ja kunstide valdkond; Tartu Ülikool. Eesti ja üldkeeleteaduse instituut
Maa ilmarekordid aina uuenevad 1
(Eesti Loodus, 2020-06) Kallis, Ain
Individually cultured bovine embryos produce extracellular vesicles that have the potential to be used as non-invasive embryo quality markers
(2020-06) Dissanayake, Keerthie; Nõmm, Monika; Lättekivi, Freddy; Ressaissi, Yosra; Godakumara, Kasun; Lavrits, Arina; Midekessa, Getnet; Viil, Janeli; Bæk, Rikke; Møller Jørgensen, Malene; Bhattacharjee, Sourav; Aneta, Andronowska; Salumets, Andres; Jaakma, Ülle; Fazeli, Alireza
Extracellular vesicles (EVs) are membrane-bound biological nanoparticles (NPs) and have gained wide attention as potential biomarkers. We aimed to isolate and characterize EVs from media conditioned by individually cultured preimplantation bovine embryos and to assess their relationship with embryo quality. Presumptive zygotes were cultured individually in 60 μl droplets of culture media, and 50 μl of media were collected from the droplets either on day 2, 5 or 8 post-fertilization. After sampling, the embryo cultures were continued in the remaining media until day 8, and the embryo development was evaluated at day 2 (cleavage), day 5 (morula stage) and day 8 (blastocyst stage). EVs were isolated using qEVsingle® columns and characterized. Based on EV Array, EVs isolated from embryo conditioned media were strongly positive for EV-markers CD9 and CD81 and weakly positive for CD63 and Alix among others. They had a cup-like shape typical to EVs as analyzed by transmission electron microscopy and spherical shape in scanning electron microscopy, and hence regarded as EVs. However, the NPs isolated from control media were negative for EV markers. Based on nanoparticle tracking analysis, at day 2, the mean concentration of EVs isolated from media conditioned by embryos that degenerated after cleaving (8.25 × 108/ml) was higher compared to that of embryos that prospectively developed to blastocysts (5.86 × 108/ml, p < 0.05). Moreover, at day 8, the concentration of EVs isolated from media conditioned by degenerating embryos (7.17 × 108/ml) was higher compared to that of blastocysts (5.68 × 108/ml, p < 0.05). Furthermore, at day 8, the mean diameter of EVs isolated from media conditioned by degenerating embryos (153.7 nm) was smaller than EVs from media conditioned by blastocysts (163.5 nm, p < 0.05). In conclusion, individually cultured preimplantation bovine embryos secrete EVs in the culture media and their concentration and size are influenced by embryo quality and may indicate their prospective development potential.
Õpilaste väärarusaamad hingamisel toimuvatest protsessidest kasutades õpilaste poolt hingamisprotsesside animeerimist
(Tartu Ülikool, 2020-06-08) Hedy, Suurmets; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Loodusteadusliku hariduse keskus
Füüsika õppimise motivatsioon gümnaasiumi õpilaste näitel
(Tartu Ülikool, 2020-06-08) Raido, Johanson; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Loodusteadusliku hariduse keskus
Tartu koorimuusika maastiku inventuur 2017-2019
(Tartu Ülikool, 2020-06-08) Arak, Triinu; Kuutma, Kristin, juhendaja; Tartu Ülikool. Humanitaarteaduste ja kunstide valdkond; Tartu Ülikool. etnoloogia osakond
Riikliku õppekava (RÕK) ja waldorf avatud tuumõppekava (WATÕK) järgi õppivate lõpuklasside õpilaste hinnangud bioloogia ja geograafia õpihuvile ning üldpädevuste arendamisele bioloogia ja geograafia tundides
(Tartu Ülikool, 2020-06-08) Malve, Marjak; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Loodusteadusliku hariduse keskus
Laste disainipõhisest õppest saadud kogemused Hullu Teadlase laagrites
(Tartu Ülikool, 2020-06-08) Anna, Katt; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Loodusteadusliku hariduse keskus
Gümnaasiumi kursus “Globaliseeruv maailm” praktikas: läbiviimine ja õpilaste tagasiside
(Tartu Ülikool, 2020-06-08) Maria, Metsaorg; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Loodusteadusliku hariduse keskus
Õuesõpe mobiilse tehnoloogia abil Saatse avastusraja näitel
(Tartu Ülikool, 2020-06-08) Meeli, Mets; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Loodusteadusliku hariduse keskus
Füüsika loovülesande lahendamise mõju õpilaste subjektiivselt tajutavale heaolule
(Tartu Ülikool, 2020-06-08) Enn, Ööpik; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Loodusteadusliku hariduse keskus
Elektriteatri külastajate persoonad ja külastusteekond
(Tartu Ülikool, 2020-06-08) Reitalu, Liisi; Koppel, Helleka, juhendaja; Tartu Ülikool. Humanitaarteaduste ja kunstide valdkond; Tartu Ülikool. etnoloogia osakond
Paternal effects in a wild-type zebrafish implicate a role of sperm-derived small RNAs
(Wiley Online Library, 2020-06-11) Ord, James; Heath, Paul R.; Fazeli, Alireza; Watt, Penelope J.
While the importance of maternal effects has long been appreciated, a growing body of evidence now points to the paternal environment having an important influence on offspring phenotype. Indeed, research on rodent models suggests that paternal stress leaves an imprint on the behaviour and physiology of offspring via nonge netic information carried in the spermatozoa; however, fish have been understudied with regard to these sperm-mediated effects. Here, we investigated whether the ze brafish was subjected to heritable influences of paternal stress by exposing males to stressors (conspecific-derived alarm cue, chasing and bright light) before mating and assessing the behavioural and endocrine responses of their offspring, including their behavioural response to conspecific-derived alarm cue. We found that after males are exposed to stress, their larval offspring show weakened responses to stressors. Small RNA sequencing subsequently revealed that the levels of several small noncoding RNAs, including microRNAs, PIWI-interacting RNAs and tRNA-derived small RNAs, were altered in the spermatozoa of stressed fathers, suggesting that stress-induced alterations to the spermatozoal RNA landscape may contribute to shaping offspring phenotype. The work demonstrates that paternal stress should not be overlooked as a source of phenotypic variation and that spermatozoal small RNAs may be important intergenerational messengers in fish.
Zeta Potential of Extracellular Vesicles: Toward Understanding the Attributes that Determine Colloidal Stability
(ACS Publications, 2020-06-30) Midekessa, Getnet; Godakumara, Kasun; Ord, James; Viil, Janeli; Lättekivi, Freddy; Dissanayake, Keerthie; Kopanchuk, Sergei; Rinken, Ago; Aneta, Andronowska; Bhattacharjee, Sourav; Rinken, Toonika; Fazeli, Alireza
Extracellular vesicles (EVs), including exosomes and microvesicles (<200 nm), play a vital role in intercellular communication and carry a net negative surface charge under physiological conditions. Zeta potential (ZP) is a popular method to measure the surface potential of EVs, while used as an indicator of surface charge, and colloidal stability influenced by surface chemistry, bioconjugation, and the theoretical model applied. Here, we investigated the effects of such factors on ZP of well-characterized EVs derived from the human choriocarcinoma JAr cells. The EVs were suspended in phosphate-buffered saline (PBS) of various phosphate ionic concentrations (0.01, 0.1, and 1 mM), with or without detergent (Tween-20), or in the presence (10 mM) of different salts (NaCl, KCl, CaCl2, and AlCl3) and at different pH values (4, 7, and 10) while the ZP was measured. The ZP changed inversely with the buffer concentration, while Tween-20 caused a significant (p < 0.05) lowering of the ZP. Moreover, the ZP was significantly (p < 0.05) less negative in the presence of ions with higher valency (Al3+/Ca2+) than in the presence of monovalent ones (Na+/K+). Besides, the ZP of EVs became less negative at acidic pH, and vice versa. The integrated data underpins the crucial role of physicochemical attributes that influence the colloidal stability of EVs.