Cloning and developmental expression of the murine neurofilament gene family.

DNA clones encoding the 3 mouse neurofilament (NF) genes have been isolated by cross-hybridization with a previously described NF-L cDNA probe from the rat. Screening of a lambda gt10 cDNA library prepared from mouse brain RNA led to the cloning of an NF-L cDNA of 2.0 kb that spans the entire coding region of 541 amino acids and of an NF-M cDNA that covers 219 amino acids from the internal alpha-helical region and the carboxy-terminal domains of the protein. These cDNA clones were used as probes to screen mouse genomic libraries, and cosmid clones containing both NF-L and NF-M sequences were isolated as well as overlapping cosmids containing the NF-H gene. This strongly suggests that the 3 neurofilament genes are organised in a cluster and derived by gene duplication of a common ancestral gene. RNA blot analyses using specific DNA probes for each of the genes indicate that NF mRNAs are differentially expressed during brain development. The NF-L and NF-M mRNAs are detected early in the embryonal brain, with a progressive increase in their levels during development, while the NF-H mRNA is barely detectable at embryonal stages and accumulates later in the postnatal brain

Seasonal Variation, Chemical Composition, and PMF-Derived Sources Identification of Traffic-Related PM₁, PM_2.5, and PM_2.5–10 in the Air Quality Management Region of Žilina, Slovakia

Particulate matter (PM) air pollution in the urban environment is mainly related to the presence of potential sources throughout the year. Road transport is one of the most important sources of PM in the urban environment, because it directly affects pedestrians. PM measurements were performed in the city of Žilina, Slovakia, at various road-traffic-related measurement stations over the course of several years. This paper evaluates changes in the concentration of the fine fraction (PM2.5), the ultrafine fraction (PM1), and the coarse fraction (PM2.5–10) over time. PM concentrations were measured by reference gravimetric method. Significant changes in PM concentrations over time due to the diversification of pollution sources and other, secondary factors can be observed from the analysis of the measured data. PM samples were subjected to chemical analysis inductively coupled plasma mass spectrometry (ICP-MS) to determine the concentrations of elements (Mg, Al, Ca, Cr, Cu, Fe, Cd, Sb, Ba, Pb, Ni, and Zn). The seasonal variation of elements was evaluated, and the sources of PM2.5, PM1, and PM2.5–10 were estimated using principal component analysis (PCA) and positive matrix factorization (PMF). PM2.5 (maximum concentration of 148.95 µg/m3 over 24 h) and PM1 (maximum concentration of 110.51 µg/m3 over 24 h) showed the highest concentrations during the heating season, together with the elements Cd, Pb, and Zn, which showed a significant presence in these fractions. On the other hand, PM2.5–10 (maximum concentration of 38.17 µg/m3 over 24 h) was significantly related to the elements Cu, Sb, Ba, Ca, Cr, Fe, Mg, and Al. High correlation coefficients (r ≥ 0.8) were found for the elements Mg, Ca, Fe, Al, Cd, Pb, and Zn in the PM1 fraction, Cd, Pb, and Zn in PM2.5, and Ba, Sb, Fe, Cu, Cr, Mg, Al, and Ca in PM2.5–10. Using PMF analysis, three major sources of PM (abrasion from tires and brakes, road dust resuspension/winter salting, and combustion processes) were identified for the PM2.5 and PM1 fractions, as well as for the coarse PM2.5–10 fraction. This study reveals the importance of non-exhaust PM emissions in the urban environment