Gender differences in pay levels : an examination of the compensation of university presidents

Our paper studies how gender and organizational status affect a university president’s compensation. Similar to previous findings, we hypothesize that women will receive less pay than men. However, we go beyond a dyadic view of individual differences to examine gender’s impact on compensation, and we explicate the importance of institutional forces in understanding the gender pay gap. In doing so, we rely on organizational status and hypothesize that the gender pay gap will be less pronounced as a university’s status rises. Although we find that the gender pay gap persists within the university president context, we also find that as a university’s status rises, the pay gap declines. Moreover, our findings show that the gender pay gap disappears at higher-status universities. Hence, accounting for where the glass ceiling is broken is an important consideration in understanding the gender pay gap. In sum, by integrating a broader institutional perspective to explain gender differences in pay levels, our paper demonstrates the importance of contextualizing gender to better understand its effects on compensation.https://pubsonline.informs.org/journal/orschj2019Human Resource Managemen

The RNA modification database, RNAMDB: 2011 update

Since its inception in 1994, The RNA Modification Database (RNAMDB, http://rna-mdb.cas.albany.edu/RNAmods/) has served as a focal point for information pertaining to naturally occurring RNA modifications. In its current state, the database employs an easy-to-use, searchable interface for obtaining detailed data on the 109 currently known RNA modifications. Each entry provides the chemical structure, common name and symbol, elemental composition and mass, CA registry numbers and index name, phylogenetic source, type of RNA species in which it is found, and references to the first reported structure determination and synthesis. Though newly transferred in its entirety to The RNA Institute, the RNAMDB continues to grow with two notable additions, agmatidine and 8-methyladenosine, appended in the last year. The RNA Modification Database is staying up-to-date with significant improvements being prepared for inclusion within the next year and the following year. The expanded future role of The RNA Modification Database will be to serve as a primary information portal for researchers across the entire spectrum of RNA-related research

Formation of m2G6 in Methanocaldococcus jannaschii tRNA catalyzed by the novel methyltransferase Trm14

The modified nucleosides N2-methylguanosine and N22-dimethylguanosine in transfer RNA occur at five positions in the D and anticodon arms, and at positions G6 and G7 in the acceptor stem. Trm1 and Trm11 enzymes are known to be responsible for several of the D/anticodon arm modifications, but methylases catalyzing post-transcriptional m2G synthesis in the acceptor stem are uncharacterized. Here, we report that the MJ0438 gene from Methanocaldococcus jannaschii encodes a novel S-adenosylmethionine-dependent methyltransferase, now identified as Trm14, which generates m2G at position 6 in tRNACys. The 381 amino acid Trm14 protein possesses a canonical RNA recognition THUMP domain at the amino terminus, followed by a γ-class Rossmann fold amino-methyltransferase catalytic domain featuring the signature NPPY active site motif. Trm14 is associated with cluster of orthologous groups (COG) 0116, and most closely resembles the m2G10 tRNA methylase Trm11. Phylogenetic analysis reveals a canonical archaeal/bacterial evolutionary separation with 20–30% sequence identities between the two branches, but it is likely that the detailed functions of COG 0116 enzymes differ between the archaeal and bacterial domains. In the archaeal branch, the protein is found exclusively in thermophiles. More distantly related Trm14 homologs were also identified in eukaryotes known to possess the m2G6 tRNA modification

Biosynthesis of Selenocysteine on Its tRNA in Eukaryotes

Selenocysteine (Sec) is cotranslationally inserted into protein in response to UGA codons and is the 21st amino acid in the genetic code. However, the means by which Sec is synthesized in eukaryotes is not known. Herein, comparative genomics and experimental analyses revealed that the mammalian Sec synthase (SecS) is the previously identified pyridoxal phosphate-containing protein known as the soluble liver antigen. SecS required selenophosphate and O-phosphoseryl-tRNA([Ser]Sec) as substrates to generate selenocysteyl-tRNA([Ser]Sec). Moreover, it was found that Sec was synthesized on the tRNA scaffold from selenide, ATP, and serine using tRNA([Ser]Sec), seryl-tRNA synthetase, O-phosphoseryl-tRNA([Ser]Sec) kinase, selenophosphate synthetase, and SecS. By identifying the pathway of Sec biosynthesis in mammals, this study not only functionally characterized SecS but also assigned the function of the O-phosphoseryl-tRNA([Ser]Sec) kinase. In addition, we found that selenophosphate synthetase 2 could synthesize monoselenophosphate in vitro but selenophosphate synthetase 1 could not. Conservation of the overall pathway of Sec biosynthesis suggests that this pathway is also active in other eukaryotes and archaea that synthesize selenoproteins

Imaging of the Inner Zone of Blast Furnaces Using MuonRadiography: The BLEMAB Project

The aim of the BLEMAB project (BLast furnace stack density Estimation through online Muons ABsorption measurements) is the application of muon radiography techniques, to image a blast furnace’s inner zone. In particular, the goal of the study is to characterize the geometry and size of the so-called “cohesive zone”, i.e., the spatial region where the slowly downward-moving material begins to soften and melt, which plays such an important role in the performance of the blast furnace itself. Thanks to the high penetration power of natural cosmic-ray muon radiation, muon transmission radiography could be an appropriate non invasive methodology for the imaging of large high-density structures such as a blast furnace, whose linear dimensions can be up to a few tens of meters. A state-of-the-art muon tracking system is currently in development and will be installed at a blast furnace on the ArcelorMittal site in Bremen (Germany), where it will collect data for a period of various months. In this paper, the status of the project and the expectations based on preliminary simulations are presented and briefly discussed

The BLEMAB European project: Muon radiography as an imaging tool in the industrial field

The European project called BLEMAB (BLast furnace stack density Estimation through on-line Muons ABsorption measurements), provides for the application of the muon radiography technique in the industrial environment. The project represents a non-invasive way of monitoring a blast furnace and in particular aims to study the geometric and density development of the so-called “cohesive zone”, which is important for the performance of the blast furnace itself. The installation of the detectors is expected in 2022 at the ArcelorMittal site in Bremen (Germany). This paper describes the status of the project, the experimental setup and the first results obtained with preliminary simulations. © 2022 Societa Italiana di Fisica. All rights reserved

An ancient family of SelB elongation factor-like proteins with a broad but disjunct distribution across archaea

<p>Abstract</p> <p>Background</p> <p>SelB is the dedicated elongation factor for delivery of selenocysteinyl-tRNA to the ribosome. In archaea, only a subset of methanogens utilizes selenocysteine and encodes archaeal SelB (aSelB). A SelB-like (aSelBL) homolog has previously been identified in an archaeon that does not encode selenosysteine, and has been proposed to be a pyrrolysyl-tRNA-specific elongation factor (EF-Pyl). However, elongation factor EF-Tu is capable of binding archaeal Pyl-tRNA in bacteria, suggesting the archaeal ortholog EF1A may also be capable of delivering Pyl-tRNA to the ribosome without the need of a specialized factor.</p> <p>Results</p> <p>We have phylogenetically characterized the aSelB and aSelBL families in archaea. We find the distribution of aSelBL to be wider than both selenocysteine and pyrrolysine usage. The aSelBLs also lack the carboxy terminal domain usually involved in recognition of the selenocysteine insertion sequence in the target mRNA. While most aSelBL-encoding archaea are methanogenic Euryarchaea, we also find aSelBL representatives in Sulfolobales and Thermoproteales of Crenarchaea, and in the recently identified phylum Thaumarchaea, suggesting that aSelBL evolution has involved horizontal gene transfer and/or parallel loss. Severe disruption of the GTPase domain suggests that some family members may employ a hitherto unknown mechanism of nucleotide hydrolysis, or have lost their GTPase ability altogether. However, patterns of sequence conservation indicate that aSelBL is still capable of binding the ribosome and aminoacyl-tRNA.</p> <p>Conclusions</p> <p>Although it is closely related to SelB, aSelBL appears unlikely to either bind selenocysteinyl-tRNA or function as a classical GTP hydrolyzing elongation factor. We propose that following duplication of aSelB, the resultant aSelBL was recruited for binding another aminoacyl-tRNA. In bacteria, aminoacylation with selenocysteine is essential for efficient thermodynamic coupling of SelB binding to tRNA and GTP. Therefore, change in tRNA specificity of aSelBL could have disrupted its GTPase cycle, leading to relaxation of selective pressure on the GTPase domain and explaining its apparent degradation. While the specific role of aSelBL is yet to be experimentally tested, its broad phylogenetic distribution, surpassing that of aSelB, indicates its importance.</p

Structural conservation of an ancient tRNA sensor in eukaryotic glutaminyl-tRNA synthetase

In all organisms, aminoacyl tRNA synthetases covalently attach amino acids to their cognate tRNAs. Many eukaryotic tRNA synthetases have acquired appended domains, whose origin, structure and function are poorly understood. The N-terminal appended domain (NTD) of glutaminyl-tRNA synthetase (GlnRS) is intriguing since GlnRS is primarily a eukaryotic enzyme, whereas in other kingdoms Gln-tRNAGln is primarily synthesized by first forming Glu-tRNAGln, followed by conversion to Gln-tRNAGln by a tRNA-dependent amidotransferase. We report a functional and structural analysis of the NTD of Saccharomyces cerevisiae GlnRS, Gln4. Yeast mutants lacking the NTD exhibit growth defects, and Gln4 lacking the NTD has reduced complementarity for tRNAGln and glutamine. The 187-amino acid Gln4 NTD, crystallized and solved at 2.3 Å resolution, consists of two subdomains, each exhibiting an extraordinary structural resemblance to adjacent tRNA specificity-determining domains in the GatB subunit of the GatCAB amidotransferase, which forms Gln-tRNAGln. These subdomains are connected by an apparent hinge comprised of conserved residues. Mutation of these amino acids produces Gln4 variants with reduced affinity for tRNAGln, consistent with a hinge-closing mechanism proposed for GatB recognition of tRNA. Our results suggest a possible origin and function of the NTD that would link the phylogenetically diverse mechanisms of Gln-tRNAGln synthesis

Ancient horizontal gene transfer and the last common ancestors

Background The genomic history of prokaryotic organismal lineages is marked by extensive horizontal gene transfer (HGT) between groups of organisms at all taxonomic levels. These HGT events have played an essential role in the origin and distribution of biological innovations. Analyses of ancient gene families show that HGT existed in the distant past, even at the time of the organismal last universal common ancestor (LUCA). Most gene transfers originated in lineages that have since gone extinct. Therefore, one cannot assume that the last common ancestors of each gene were all present in the same cell representing the cellular ancestor of all extant life. Results Organisms existing as part of a diverse ecosystem at the time of LUCA likely shared genetic material between lineages. If these other lineages persisted for some time, HGT with the descendants of LUCA could have continued into the bacterial and archaeal lineages. Phylogenetic analyses of aminoacyl-tRNA synthetase protein families support the hypothesis that the molecular common ancestors of the most ancient gene families did not all coincide in space and time. This is most apparent in the evolutionary histories of seryl-tRNA synthetase and threonyl-tRNA synthetase protein families, each containing highly divergent “rare” forms, as well as the sparse phylogenetic distributions of pyrrolysyl-tRNA synthetase, and the bacterial heterodimeric form of glycyl-tRNA synthetase. These topologies and phyletic distributions are consistent with horizontal transfers from ancient, likely extinct branches of the tree of life. Conclusions Of all the organisms that may have existed at the time of LUCA, by definition only one lineage is survived by known progeny; however, this lineage retains a genomic record of heterogeneous genetic origins. The evolutionary histories of aminoacyl-tRNA synthetases (aaRS) are especially informative in detecting this signal, as they perform primordial biological functions, have undergone several ancient HGT events, and contain many sites with low substitution rates allowing deep phylogenetic reconstruction. We conclude that some aaRS families contain groups that diverge before LUCA. We propose that these ancient gene variants be described by the term “hypnologs”, reflecting their ancient, reticulate origin from a time in life history that has been all but erased”.National Science Foundation (U.S.) (Grant DEB 0830024)Exobiology Program (U.S.) (Grant NNX10AR85G)United States. National Aeronautics and Space Administration (Postdoctoral Program