BMP ja Pax signaalmolekulide avaldumine inimese ja roti embrüote kesknärvisüsteemi varajastel arenguetappidel

A Thesis for applying for the degree of Doctor of Philosophy in Veterinary ScienceThe roles of BMP and Pax in the embryonic development have been extensively studied in recent years and the formation of the neural tube is usually described as a self-evident process, but formation of nervous system in human embryos has actually not been examined in detail. In the present study 40 human embryos at Carnegie stages (CS) 10-20 were obtained, and the expression of BMP-2, BMP-4, Pax2, Pax6 and Pax7 proteins were examined in the developing brain. 22 rat embryos of CS 14, 18 and 20 were employed to compare the BMP-2, BMP-4 and Pax2 expression in the developing spinal cord of human and rat embryos throughout early stages of the nervous system development. To detect expression of proteins the method of immunohistochemistry was used. BMP-2 and BMP-4 are essential signalling molecules for the formation of the neural tube in human embryos as their expression was seen throughout all studied developmental stages 10-20. The expression of both proteins, BMP-2 and BMP-4, had a tendency to decline in the later stages of the development. In the developing CNS of rat embryos BMP-2 and BMP-4 have a similar spatial and temporal expression pattern compared to the corresponding stages of the human embryos. However, slight differences were noted as in the spinal cord of rat embryos BMP-2 and BMP-4 expression was weaker compared to human embryos. In the human embryos Pax2, Pax6 and Pax7 were identified as signalling molecules that are involved in the formation of the early spinal cord and brain. The expression of Pax2, Pax6 and Pax7 had a tendency to increase in the later stages of the development both in the spinal cord and the brain. Significantly weaker expression of the Pax proteins was observed at CS 10. The similar temporal expression pattern of Pax2 to human embryos was seen in the forming spinal cord of rat embryos, as the Pax2 expression was found to increase at the later stages of the development. Differently from human embryos, no clear regional differences in Pax2 expression in the developing spinal cord of the rat embryos were not seen. It can be said that in the human and rat embryos BMP-2, BMP-4, Pax2, Pax6 and Pax7 proteins are associated with the establishment of neuroepithelial cells within the developing neural tube and with the migration and the differentiation of specific neural cell populations. In particular, the studied signalling molecules play an essentially important role in the determining of the dorsal-ventral and rostral-caudal axis of the developing brain.BMP ja Pax valgud on ühed olulisemad signaalmolekulid imetajate neuraaltoru moodustumisel ja edasises kesknärvisüsteemi arengus. BMP ja Pax valkude osalusest inimembrüo närvisüsteemi varajases arengus on siiani ilmunud üksikud teadusartiklid. Käesoleva töö eesmärgiks oli uurida BMP-2, BMP-4, Pax2, Pax6 ja Pax7 ekspressiooni inimembrüo arenevas pea- ja seljaajus. Lisaks inimembrüotele analüüsiti BMP-2, BMP-4 ja Pax2 avaldumist rottide embrüote seljaajus. Uuringuteks kogutud embrüod jäid Carnegie arenguetappidesse 10–20, roti embrüod vastavalt 14, 18 ja 20 arenguetappi. BMP ja Pax valkude ekspressiooni hindamiseks kasutati immunohistokeemilist meetodit. BMP ja Pax signaalmolekulide ekspressioon avaldus kõigis uuritud etappides 10–20. Nii BMP-2 kui ka BMP-4 avaldumisel ilmnes hilisemates arenguetappides ekspressiooni nõrgenemise tendents. BMP-2 ja BMP-4 on olulised kasvufaktorid inimembrüo seljaaju dorsoventraalse telje väljakujunemisel, eriti etappides 16–18, kus antud töö tulemused näitasid BMP-de tugevamat ekspressiooni areneva seljaaju dorsaalosas võrreldes ventraalosaga. Roti arenevas seljaajus ilmnes võrreldes inimembrüote vastavate arenguetappidega ajalise ja ruumilise BMP-2 ja BMP-4 ekspressiooni sarnasus. Nii Pax2, Pax6 kui Pax7 avaldumise hindamisel selgus ekspressiooni tugevnemine hilisematel arenguetappidel. Pax valkude ekspressioon etappidel 10–14 näitab antud signaalmolekulide vajalikkust seljaaju dorsoventraalse telje ja ajuvatsakeste moodustumisel. Hilisemates etappides 16–20 on Pax2, Pax6 ja Pax7 kaasatud ees-, kesk- ja tagaaju mitmete erinevate piirkondade arengusse. Roti ja inimembrüo arenevas seljaajus avaldus sarnane Pax2 ajaline ekspressioon – Pax2 signaal tugevnes hilisematel arenguetappidel. Erinevalt inimembrüotest, ei ilmnenud rottide embrüotel arenevas seljaajus Pax2 avaldumises selgeid regionaalseid erinevusi dorsaalse ja ventraalse poole vahel. Kokkuvõtlikult võib öelda, et BMP-2, BMP-4, Pax2, Pax6 ja Pax7 on olulisel määral seotud neuroepiteeli rakkude formeerumise, migreerumise ja diferentseerumisega erinevateks närvirakkude populatsioonideks. Uuritud singnaalmolekulid on inimese ja roti embrüote varajases kesknärvisüsteemi arengus määrava tähtsusega dorsoventraalse ja kraniokaudaalse telje väljakujunemisel.Publication of this dissertation is granted by the Estonian University of Life Science

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Delineating Wetlands in Serpentinitic Soils

Wetlands serve an important ecological and functional role in the environment. In order to protect wetlands from degradation, the determination of wetland hydrology, hydrophytic vegetation, and hydric soils is necessary. Soils formed from serpentine parent material on hillside slump blocks do not meet any of the current morphological Field Indicators of Hydric Soils. Although these areas seem to be wetlands based on wetland hydrology and hydrophytic vegetation, there is no approved hydric soil indicator that includes the properties exhibited by serpentinitic soils on these landscapes. The objectives of this research were: (1) to examine soil chemical, physical, and morphological properties to determine if they meet the criteria for hydric soils; and (2) to develop a new test Field Indicator of Hydric Soil for use in soils formed in serpentinitic parent materials along the Central Coast of California. Two research sites in Poly Canyon, north of California Polytechnic State University in San Luis Obispo, were instrumented with Indicator of Reduction in Soil (IRIS) tubes over a three month period to measure the amount of Fe reduction in the soil profiles to a depth of 50 cm. The results of the IRIS tube analyses displayed anaerobic conditions persisting for longer than 14 days during the growing season; therefore, these soils are in fact hydric. The development of a new test Field Indicator of Hydric Soil is necessary. Preliminarily, the following is proposed as a new test indicator: soils formed in serpentine parent material occurring on a slump block landforms with a layer at least 10 cm (4 in) thick, no chroma color with a value of 2 or less, and few or less concentrations. The layer is entirely within 30 cm (12 in) of the soil surface. Further research to test this new field indicator includes an additional research site and a year of supplementary data

Pax proteins in embryogenesis and their role in nervous system development

The mammalian Pax genes encode a family of transcription factors, which play important roles in embryonic development and organogenesis. During the central nervous system development Pax genes have substantial roles in neural differentiation and regional specification. Pax proteins are expressed in populations of nerve cells within the developing forebrain, midbrain, hindbrain and spinal cord. In this article the fundamental roles of Pax proteins in the embryogenesis are outlined and the temporal and spatial influences of Pax on the formation of the central nervous system are discussed

Expression of Pax2 protein during the formation of the central nervous system in human embryos

Members of the paired box (Pax) gene family are expressed in distinctive regions of the developing central nervous system, supporting a role of neural patterning. In this study, Pax2 protein expression was examined in the developing neural tube by immunohistochemistry methods in 30 human embryos of Carnegiestages (CS) 10–20 collected after legal abortions. Pax2 expression was detected along the boundaries of main divisions of the developing brain and spinal cord. However, Pax2 expression was found to be stronger in the developing brain than in the spinal cord of the same young embryos in CS 10–14, which was the mostremarkable at CS 10. Pax2 expression was detected in the developing forebrain,midbrain and hindbrain. At later stages (CS 16–20) Pax2 expression was observed in the midbrain-hindbrain boundary and also in the developing diencephalon and cerebellum. In the wall of developing spinal cord Pax2 expression was detected in the ventricular, mantel and marginal layers. Pax2 staining was seen to increase throughout the later stages of spinal cord development and significantly stronger expression was found at CS 16–20 compared to CS 10. Furthermore, spatially restricted expression of Pax2 was observed along the compartmental dorsal-ventralaxis of the spinal cord as Pax2 staining was weaker in the ventricular layer of the ventral part of the developing spinal cord compared with developing area of dorsal part

Testing the myths of transition: was Estonia following the shock therapy model and Slovenia following the gradualist model in 1991-2000?

The aim of this paper is to conduct an exploratory analysis of factors that might explain the cross-national variations in the level tax morality across the European Union. In order to do this, three competing explanations for the cross-national variations in tax morality will be evaluated which variously view lower levels of tax morality to be a result of either: under-development (a modernisation explanation); high taxes, state corruption and too much state interference (a neo-liberal explanation), or too little state redistribution and intervention to protect citizens (a structuralist explanation). Evaluating the cross-national variations in tax morality reported in a 2007 Eurobarometer survey using multi level econometric techniques, the finding is that the tax morality of a baseline European citizen is higher in more developed and less corrupt nations and in countries with higher levels of taxation, social protection and redistribution. The outcome is a call for a synthesis of the three explanations in the form of a new neo-modernisation explanation which, contrary to neo-liberal discourse, argues that developed nations with higher levels of taxation, greater levels of social protection and higher levels of redistribution have higher levels of tax morality. The tentative policy implications are then discussed

BMP-2 and BMP-4 signalling in the developing spinal cord of human and rat embryos

Bone morphogenetic proteins (BMPs) are multifunctional growth factors implicated in multiple biological events. Studies on mice, chickens and other experimental animals have shown that BMP signalling plays critical role in embryonic development, in particular in the neural patterning. In our study we comparatively evaluated BMP-2 and BMP-4 protein expression in the developing spinal cord of human and rat embryos. The human and rat embryos of Carnegie stages 14, 18 and 20 were embedded in paraffin and cut serially in transversal direction. BMP-2 and BMP-4 were detected by immunohistochemical staining. Spatial and temporal expression pattern of BMP-s during early stages of spinal cord development was similar in human and rat embryos. Higher expression of BMP-s was seen in the dorsal and lower expression in the ventral part of the developing spinal cord both in human and rat embryos. However, temporal difference in the expression of BMPs in the non-neural ectoderm between human and rat embryos was noted. Staining of BMP-s in the non-neural ectoderm adjacent to the developing spinal cord in the human embryos seemed to have a tendency to decrease from earlier to later developmental stages, while in rat embryos there was an opposite tendenc

Autoriõiguste kaitse ja rahvusvaheline võltsimisvastane kaubandusleping

http://tartu.ester.ee/record=b2612626~S1*es