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Abstract: ZEB2 is a transcription factor with established roles in neurogenesis but no defined function in postnatal brain despite extensive neuronal expression in telencephalic structures. Multiple, incompletely annotated transcripts derive from the Zeb2 locus; the purpose of the present study was to structurally characterize rat brain Zeb2 transcripts with respect to 3′ untranslated (UTR) sequence in order to understand Zeb2 transcript regulation including possible interactions with regulatory molecules such as neuronal miRNAs. We cloned a 5054-nucleotide Zeb2 3′ UTR that is included in the most abundant Zeb2 transcript in neonatal rat brain. Unique features of the distal 3′ UTR region included a number of brain-specific miRNA target sites; a highly conserved miR-9 target site at 3′ UTR position 4097 was selected for functional verification in transfection experiments. Parallel analysis of Zeb2 transcript, ZEB2 protein and miR-9 levels across postnatal brain cortical development revealed a significant accumulation of ZEB2 protein levels only between postnatal days P2 and P5 that was associated with an acute loss of postnatal miR-9 expression in cortex. These studies demonstrate novel features of Zeb2 gene expression in postnatal rat brain and highlight the importance of full transcript annotation for identifying the complement of potential transcript-interacting regulators.
Keywords: transcription factor, RNA, untranslated region, miRNA, brain, rat
Published in RUNG: 11.11.2024; Views: 194; Downloads: 3
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Keywords: black carbon, emission factor, source apportionment
Published in RUNG: 24.01.2023; Views: 2553; Downloads: 22
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Abstract: Polycyclic aromatic hydrocarbons (PAHs) are compounds known for their adverse effects on human health. Many of them are proven carcinogens, especially those with 5 and 6 aromatic rings, which under normal tropospheric conditions are found in the particle-phase. Benzo(a)pyrene (BaP) is often measured as their general representative. Sarajevo, the capital of Bosnia and Herzegovina, is among the European cities with the poorest air quality. However, in Sarajevo PAHs are neither routinely measured within the air quality monitoring network nor have been a subject of extended, continuous field studies during the most polluted cold periods of the year. The capital of Croatia, Zagreb, is located approximately 300 km air distance north-west from Sarajevo. PAH mass concentrations in Zagreb have been measured continuously since 1994 within air quality monitoring networks. During winter 2017/2018, the SAFICA project (Sarajevo Canton Winter Field Campaign 2018) was carried out in order to characterize the chemical composition of organic and inorganic aerosol in the Sarajevo Canton. This paper presents the results of PAH measurements in the cities of Sarajevo and Zagreb at one urban location per city. Daily (24 h), continuous samples of PM10 (particulate matter with aerodynamic diameters ≤10 μm) were collected during heating season, from December 27, 2017 to February 27, 2018. Mass concentrations of eleven particle-phase PAHs in Sarajevo and Zagreb from filter samples collected during the same period were compared. The average BaP ambient mass concentrations in Sarajevo and Zagreb were 6.93 ng m−3 and 3.11 ng m−3, respectively. The contribution of BaP to the total PAH mass concentration was similar at both locations (11%). However, much higher contributions of particle-phase fluoranthene and pyrene were found in Sarajevo. Contributions of individual PAH, diagnostic ratios and factor analysis indicate that combustion of gasoline and diesel from vehicle traffic are a potential source of PAHs at both locations, as well as combustion of other liquid fossil fuels (petroleum and fuel oil). Wood burning was occasionally indicated as a PAH emission source in Zagreb, while in Sarajevo the contribution of PAHs from wood and coal combustion was more evident. Calculated value for total carcinogenic potency (TCP) of PAHs, which was estimated using toxic equivalence factors from the literature, in PM10 samples collected in Sarajevo was more than twice higher than in Zagreb (10.6 ng m−3 and 4.7 ng m−3, respectively). BaP had the highest contribution to the TCP at both locations (69 and 67%).
Keywords: carcinogenic potency, diagnostic ratio, factor analysis, PM10, polycyclic aromatic hydrocarbons
Published in RUNG: 09.04.2021; Views: 3052; Downloads: 0
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Abstract: Inventories of methyl halide emissions from domestic burning of biomass in Africa, from 1950 to the present day and projected to 2030, have been constructed. By combining emission factors from Andreae and Merlet [2001. Emission of trace gases and aerosols from biomass burning. Global Biogeochemical Cycles 15, 955-966], the biomass burning estimates from Yevich and Logan [2003. An assessment of biofuel use and burning of agricultural waste in the developing world. Global Biogeochemical Cycles 17(4), 1095, doi:10.1029/2002GB001952] and the population data from the UN population division, the emission of methyl halides from domestic biomass usage in Africa has been estimated. Data from this study suggest that methyl halide emissions from domestic biomass burning have increased by a factor of 4-5 from 1950 to 2005 and based on the expected population growth could double over the next 25 years. This estimated change has a non-negligible impact on the atmospheric budgets of methyl halides.
Keywords: Africa, Biofuel, Domestic biomass burning, Emission factor, Methyl halide
Published in RUNG: 17.07.2019; Views: 4069; Downloads: 0
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Abstract: In my master's thesis, I have focused on radon gas in 43 buildings used for different purposes (23 schools, 3 kindergartens, 16 offices and a residential house) in which preliminary measurements had shown higher concentrations of radon gas. I carried out measurements of radon and short-lived radon products whilst simultaneously employing different measurement techniques. In all 43 buildings, I measured the instantaneous concentration of radon by using scintillation cells; in 18 buildings, I additionally measured the average concentration of radon by using solid state nuclear track detectors and in 10 buildings, I measured concentration retrospectively with solid state nuclear track detectors. In four selected buildings (a school, a kindergarten, an office and a residential house), I carried out the measurements by using all of the available equipment. I monitored the daily fluctuations of concentration of radon and short-lived radon products by using continuous monitors in 14 buildings. This is how I obtained the factor of radioactive equilibrium between radon and its short-lived products. Based on the results obtained, I calculated the effective doses. As the basis for calculating the doses, I used the instantaneous and average concentrations of radon and the equilibrium factor taken from literature (0.40) or own measurements. I compared the doses and critically evaluated them. In contrast to the previous research, I researched radon exclusively in areas with increased risk for radon. I studied the influence of the working regime on the concentration of radon in different working environments (i.e. a school, a kindergarten and an office).
Keywords: Radon, short-lived radon products, measurement technique, scintillation cell, solid-state nuclear track detector, retrospective detector, equilibrium factor, effective dose, comparison.
Published in RUNG: 28.09.2016; Views: 7376; Downloads: 289
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