10 research outputs found

    Dynamics of phytoplankton pigments in water and surface sediments of a large shallow lake

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    Our aim was to find out to which extent fossil phytoplankton pigments in the large shallow and turbid Lake Võrtsjärv carry information on the history of phytoplankton communities. For this purpose we examined how the changes in the pigment composition of surface sediments follow their changes in the water column. Depth-integrated lake water and surface sediment samples were collected weekly in May–October 2007. Considering cyanobacterial and diatom dominance in phytoplankton, we analysed fucoxanthin, diadinoxanthin and diatoxanthin as marker pigments for diatoms, zeaxanthin as a marker pigment for total cyanobacteria and canthaxanthin as a marker pigment for colonial cyanobacteria. Chlorophyll a and its derivative pheophytin a were applied as indicators for total phytoplankton. The dynamics of phytoplankton pigments in surface sediments generally did not follow their dynamics in the water column, possibly due to intensive resuspension and a high sedimentation rate in a large and shallow lake. It was noticed that the surface sediment carries information on pigment degradation intensity and on weight and size characteristics of phytoplankton cells, which affect their sinking and floating velocities. Higher pigment contents of sediment in spring were presumably caused by lower resuspension due to high water level and slower degradation in cold water. Pheophytin a and the marker pigments of cyanobacteria were found to be persistent against degradation in upper sediment layers, which makes them useful indicators for tracking the historical changes in phytoplankton communities also in a shallow lake. Sharp decrease in chemically unstable pigment contents between the sediment surface and deeper layers indicates that only the uppermost sediment surface is resuspended in Lake Võrtsjärv. The transformation of the diatom marker carotenoid diadinoxanthin to diatoxanthin was found to occur mainly in sediments and not in the water column, and the process is not induced by excess light

    Veise sigimine: kõrgkooliõpik

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    Eestis on veisekasvatusest lugu peetud juba kiviajast peale. Meil on heade tõuomadustega ja suure toodanguga piimakari ja kiiresti kasvav lihakari ning me suudame toota kvaliteetset piima ja veiseliha nii kohalikele tarbijatele kui ka ekspordiks. Veiste sigimisprobleemid on oluliseks veisekasvatuse kasumlikkust mõjutavaks teguriks. Selleks, et sigimisprobleemide olemust mõista ja nende teket ennetada või neid ravida, on vajalikud põhjalikud teadmised veise sigimise erinevatest aspektidest. Seni puudub üks terviklik veise sigimise alast teavet koondav eestikeelne õppevahend. Käesoleva õpiku abil soovime seda lünka täita. Oleme õpikusse kokku kogunud teadmised suguorganite morfoloogiast ja füsioloogiast, tiinusest ja sünnitusest ning poegimisjärgsetest haigustest. Suguorganite anatoomiat käsitletakse õpikus mitte klassikalise, vaid funktsionaalse anatoomia seisukohast. Veise tiinuse ja sünnituse

    Individually cultured bovine embryos produce extracellular vesicles that have the potential to be used as non-invasive embryo quality markers

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    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 Peer reviewe

    Veise sigimine : kõrgkooliõpik

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    KõrgkooliõpikÜlle Jaakma ja Mihkel Jalakase toimetatud õpik „Veise sigimine“ valiti 2018. aasta parimaks eestikeelseks kõrgkooliõpikuks.Eestis on veisekasvatusest lugu peetud juba kiviajast peale. Meil on heade tõuomadustega ja suure toodanguga piimakari ja kiiresti kasvav lihakari ning me suudame toota kvaliteetset piima ja veiseliha nii kohalikele tarbijatele kui ka ekspordiks. Veiste sigimisprobleemid on oluliseks veisekasvatuse kasumlikkust mõjutavaks teguriks. Selleks, et sigimisprobleemide olemust mõista ja nende teket ennetada või neid ravida, on vajalikud põhjalikud teadmised veise sigimise erinevatest aspektidest. Seni puudub üks terviklik veise sigimise alast teavet koondav eestikeelne õppevahend. Käesoleva õpiku abil soovime seda lünka täita. Oleme õpikusse kokku kogunud teadmised suguorganite morfoloogiast ja füsioloogiast, tiinusest ja sünnitusest ning poegimisjärgsetest haigustest. Suguorganite anatoomiat käsitletakse õpikus mitte klassikalise, vaid funktsionaalse anatoomia seisukohast. Veise tiinuse ja sünnituse patoloogia osas antakse ülevaade ka väärarendite ja abordi problemaatikast. Esmakordselt käsitletakse eestikeelses õpikus kaasaegset sigimise biotehnoloogiat, sh embrüotehnoloogiat ja transgeenset tehnoloogiat, koos võimalike rakendustega aretustöös. Õpik on mõeldud eeskätt veterinaarmeditsiini eriala üliõpilastele, aga seda saavad käsiraamatuna kasutada ka praktiseerivad loomaarstid, seemendustehnikud ja loomakasvatuse spetsialistid. Lisaks sellele saavad siit informatsiooni bioloogia eriala üliõpilased ja biotehnoloogia ning kliinilise diagnostika spetsialistid, samuti bioloogiaõpetajad. Õpiku autorid on õppejõud ja teadlased, kes on oma kitsama valdkonna tunnustatud asjatundjad ning puutuvad oma töös käsitletud teemade ringi puudutavate probleemidega kokku iga päev. Täname kõiki autoreid nende suure panuse eest õpiku valmimisse. Suur tänu Eha Järvele, kes on rahulikult ja asjatundlikult aidanud eri autorite kirjutatud osad üheks tervikuks ühendada. Oleme tänulikud kõigile kolleegidele, kes oma tähelepanekute ja soovitustega on selle raamatu valmimisel kaasa aidanud. Loodame, et õpik pakub nii õppuritele kui ka praktikutele kasulikku ja vajalikku informatsiooni. Ülle Jaakma õpiku toimetaj

    Detecting Embryo Developmental Potential by Single Blastomere RNA-Seq

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    Recent advances in preimplantation embryo diagnostics enable a wide range of applications using single cell biopsy and molecular-based selection techniques without compromising embryo production. This study was conducted to develop a single cell embryo biopsy technique and gene expression analysis method with a very low input volume to ensure normal embryo development and to see if there are differences in gene expression profiles between day-5 biopsied bovine embryos that developed into blastocysts and embryos arrested at morula stage. Out of the 65 biopsied morulae, 32 developed to blastocysts (49.2%). Out of the 13,580 successfully annotated genes, 1204 showed a difference in mRNA expression level. Out of these, 155 genes were expressed in embryos developing to blastocysts. The pathway enrichment analysis revealed significant enrichment in “organelle biogenesis and maintenance”, “mRNA splicing” and “mitochondrial translation” pathways. These findings suggest principal differences in gene expression patterns and functional networks of embryos able to reach the blastocyst stage compared to embryos arrested in development. Our preliminary data suggest that single blastomere biopsy and selected gene expression profiles at morula stage could offer additional possibilities for early preimplantation embryo selection before transfer

    Animal reproduction, technology and welfare, December 3-4, 2018, Estonian University of Life Sciences, Tartu, Estonia : [photos]

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    PhotosPhotos of the final conference of the SEARMET "Animal reproduction, technology and welfare".Photos 1, 2, 3, 4, 11, 12, 17, 28, 29 by Mari-Liis Koemets. Photos 20, 23, 36, 37, 38, 39, 40, 41, 44, 45, 46 by Monika Nõmm. Photos 5, 6, 7, 8, 9, 10, 13, 14, 15, 16, 18, 19, 21, 22, 24, 25, 26, 27, 30, 31, 32, 33, 34, 35, 42, 43, 47, 48, 49, 50, 51, 52, 53 by Marilin Ivask

    Holocene shifts in the primary producer community of large, shallow European Lake Peipsi, inferred from sediment pigment analysis

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    We used HPLC to identify and quantify pigments in a Holocene sediment record from large, shallow Lake Peipsi, Estonia. The aim of our study was to track the influence of long-term climate change (i.e. temperature fluctuations) on past dynamics of aquatic primary producers. Sedimentary pigments were separated and quantified in 182 samples that span the last ca. 10,000 years. There was an increasing trend in sedimentary pigment concentrations from basal to upper sediment layers, suggesting a gradual increase in lake trophic status through time. Using additive models, our results suggested that primary producer dynamics in Lake Peipsi were closely related to temperature fluctuations. We, however, identified two periods (early Holocene and after ca. 2.5 cal ka BP) when the relationship between primary producer composition and temperature was weak, suggesting the influence of additional drivers on the primary producer community. We postulate that: (a) the increase of primary producer biomass in the early Holocene could have been caused by input of allochthonous organic matter and nutrients from the flooded areas when water level in Lake Peipsi was increasing, and (b) changes in the abundance and structure of primary producer assemblages since ca. 2.5 cal ka BP was related to widespread agricultural activities in the Lake Peipsi catchment. These results suggest that human activities can disrupt the relationship between the primary producer community and temperature in large, shallow lakes.This research was supported by institutional research grants IUT21-2, IUT1-8 and PRG323 and Estonian Science Foundation Grants Nos. 6741, 7888 and 9102. We acknowledge colleagues S. Veski, A. Heinsalu and J. Vassiljev for sediment coring and establishing the chronology, and A. Leeben for participating in the early stage of manuscript development. We are grateful for the comments and corrections made by two anonymous reviewers of the manuscript.This research was supported by institutional research grants IUT21-2, IUT1-8 and PRG323 and Estonian Science Foundation Grants Nos. 6741, 7888 and 9102. We acknowledge colleagues S. Veski, A. Heinsalu and J. Vassiljev for sediment coring and establishing the chronology, and A. Leeben for participating in the early stage of manuscript development. We are grateful for the comments and corrections made by two anonymous reviewers of the manuscript

    Spermatozoa induce transcriptomic alterations in bovine oviductal epithelial cells prior to initial contact

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    The capability of spermatozoa to directly influence maternal gene expression is already established. Indeed, some of the changes induced by spermatozoa may have a direct functional importance in the pre-conceptional period. Although the mechanisms underlying these sperm-maternal interactions are not well characterized, it is possible that they could involve ligands that are released from the spermatozoa. This study therefore aimed to test whether physical contact between bovine spermatozoa and bovine oviductal epithelial cells (BOECs) is a prerequisite for spermatozoa-induced gene expression changes. We used two co-culture models: a contact co-culture model in which spermatozoa interact directly with BOECs, and a non-contact co-culture model in which an insert with the pore size of 0.4 μm was placed between spermatozoa and BOECs. Messenger RNA sequencing analysis of BOECs by RNA-seq revealed ten differentially expressed genes in contact system and 108 differentially expressed genes in the non-contact system after 10 h of co-culture. Retinol metabolism pathway and ovarian steroidogenesis pathway were significantly enriched in the non-contact co-culture system. Q-PCR analysis revealed that transcriptional responses can be rapid, with increased expression of four genes (DHRS3, CYP1B1, PTGS2, and ATF3) detectable within just 90 min of co-incubation, but with expression levels highly dependent on the type of co-culture system. The findings from our study demonstrate that direct contact with spermatozoa is not necessary to induce changes in gene expression of oviductal epithelial cells, suggesting that spermatozoa may be able to signal to maternal tissues in advance of their arrival
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