Getting Educated : Working Class and First-Generation Students and the Extra-Curriculum

Previous research shows that participation in the extra-curriculum supports college students\u27 integration, but participation varies based on students\u27 background: working class students and first-generation college students tend to participate less. I contribute to this literature by analyzing interview data. I find students differ in how they participate in activities and integrate into college based on their likelihood of attending an elite institution. Working-class and first-generation students participate in activities as an extension of academics, while other students participate for social reasons, resulting in different experiences of campus life. This difference can restrict students\u27 gains in social and cultural capital, potentially limiting any decrease in inequality that results from elite college access

Chromosome structure: improved immunolabeling for electron microscopy

To structurally dissect mitotic chromosomes, we aim to position along the folded chromatin fiber proteins involved in long-range order, such as topoisomerase IIα (topoIIα) and condensin. Immuno-electron microscopy (EM) of thin-sectioned chromosomes is the method of choice toward this goal. A much-improved immunoprocedure that avoids problems associated with aldehyde fixation, such as chemical translinking and networking of chromatin fibers, is reported here. We show that ultraviolet irradiation of isolated nuclei or chromosomes facilitates high-level specific immunostaining, as established by fluorescence microscopy with a variety of antibodies and especially by immuno-EM. Ultrastructural localizations of topoIIα and condensin I component hBarren (hBar; hCAP-H) in mitotic chromosomes were studied by immuno-EM. We show that the micrographs of thin-sectioned chromosomes map topoIIα and hBar to the center of the chromosomal body where the chromatin fibers generally converge. This localization is defined by many clustered gold particles with only rare individual particles in the peripheral halo. The data obtained are consistent with the view that condensin and perhaps topoIIα tether chromatin to loops according to a scaffolding-type mode

Experimental data from flesh quality assessment and shelf life monitoring of high pressure processed European sea bass (Dicentrarchus labrax) fillets

Fresh fish are highly perishable food products and their short shelf-life limits their commercial exploitation and leads to waste, which has a negative impact on aquaculture sustainability. New non-thermal food processing methods, such as high pressure (HP) processing, prolong shelf-life while assuring high food quality. The effect of HP processing (600MPa, 25 °C, 5min) on European sea bass (Dicentrarchus labrax) fillet quality and shelf life was investigated. The data presented comprises microbiome and proteome profiles of control and HP-processed sea bass fillets from 1 to 67 days of isothermal storage at 2 °C. Bacterial diversity was analysed by Illumina high-throughput sequencing of the 16S rRNA gene in pooled DNAs from control or HP-processed fillets after 1, 11 or 67 days and the raw reads were deposited in the NCBI-SRA database with accession number PRJNA517618. Yeast and fungi diversity were analysed by high-throughput sequencing of the internal transcribed spacer (ITS) region for control and HP-processed fillets at the end of storage (11 or 67 days, respectively) and have the SRA accession number PRJNA517779. Quantitative label-free proteomics profiles were analysed by SWATH-MS (Sequential Windowed data independent Acquisition of the Total High-resolution-Mass Spectra) in myofibrillar or sarcoplasmic enriched protein extracts pooled for control or HP-processed fillets after 1, 11 and 67 days of storage. Proteome data was deposited in the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifiers PXD012737. These data support the findings reported in the associated manuscript "High pressure processing of European sea bass (Dicentrarchus labrax) fillets and tools for flesh quality and shelf life monitoring", Tsironi et al., 2019, JFE 262:83-91, doi.org/10.1016/j.jfoodeng.2019.05.010.FCT (Foundation of Science and Technology) COFASP/0002/2015; Portuguese Foundation for Science and Technology UID/Multi/04326/2019 POCI-01-0145-FEDER007440 UID/NEU/04539/2019info:eu-repo/semantics/publishedVersio

Mutation analysis of the different tfd genes for degradation of chloroaromatic compounds in Ralstonia eutropha JMP134

Ralstonia eutropha JMP134 possesses two sets of similar genes for degradation of chloroaromatic compounds, tfdCDEFB (in short: tfd I cluster) and tfdD II C II E II F II B II (tfd II cluster). The significance of two sets of tfd genes for the organism has long been elusive. Here, each of the tfd genes in the two clusters on the original plasmid pJP4 was replaced by double recombination with a gene fragment in which a kanamycin resistance gene was inserted into the respective tfd gene's reading frame. The insertion mutants were all tested for growth on 2,4-dichlorophenoxyacetic acid (2,4-D), 2-methyl-4-chlorophenoxyacetic acid (MCPA), and 3-chlorobenzoate (3-CBA). None of the tfdD II C II E II F II B II genes appeared to be essential for growth on 2,4-D or on 3-CBA. Mutations in tfdC, tfdD and tfdF also did not abolish but only retarded growth on 2,4-D, indicating that they were redundant to some extent as well. Of all tfd genes tested, only tfdE and tfdB were absolutely essential, and interruption of those two reading frames abolished growth on 2,4-D, 3-CBA (tfdE only), and MCPA completely. Interestingly, strains with insertion mutations in the tfd I cluster and those in tfdD II , tfdC II , tfdE II and tfdB II were severely effected in their growth on MCPA, compared to the wild-type. This indicated that not only the tfd I cluster but also the tfd II cluster has an essential function for R. eutropha during growth on MCPA. In contrast, insertion mutation of tfdD II resulted in better growth of R. eutropha JMP134 on 3-CBA, which is most likely due to the prevention of toxic metabolite production in the absence of TfdDII activit

Immunocytochemical localization of chromatin regions UV-microirradiated in S phase or anaphase : Evidence for a territorial organization of chromosomes during cell cycle of cultured Chinese hamster cells

Chinese hamster cells (M3-1 line) in S phase were laser-UV-microirradiated (λ, 257 nm) at a small site of the nucleus. Cells were fixed either immediately thereafter or in subsequent stages of the cell cycle, including prophase and metaphase. The microirradiated chromatin was visualized by indirect immunofluorescence microscopy using antibodies specific for UV-irradiated DNA. During the whole post-incubation period (4–15 h) immunofluorescent labelling was restricted to a small part of the nucleus ( , 4.5 % of the total nuclear area). In mitotic cells segments of a few chromosomes only were labelled. Following microirradiation of chromosome segments in anaphase, immunofluorescent labelling was observed over a small part of the resulting interphase nucleus. A territorial organization of interphase chromosomes, i.e. interphase chromosomes occupying distinct domains, has previously been demonstrated by our group for the nucleus of Chinese hamster cells in G1. Our present findings provide evidence that this organization pattern is maintained during the entire cell cycle

Purification of alpha-toxin from Staphylococcus aureus and application to cell permeabilization

Crude alpha-toxin was produced by Staphylococcus aureus, strain Wood 46. The amount of exotoxin was monitored during growth and all subsequent purification steps by determination of its hemolytic activity against rabbit erythrocytes. The culture supernatant was treated with ammonium sulfate (75% saturation). The resulting precipitate was dialyzed and subjected to cation-exchange chromatography. The fractions containing the hemolytic activity were further purified by gel chromatography. The final product was enriched by a factor of 8.5 compared to the crude toxin. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis the purified toxin exhibited one major band. It caused the release of 86Rb+ and ATP from rat insulinoma (RIN A2) as well as pheochromocytoma cells (PC12) in culture, indicating efficient permeabilization of their plasma membranes for small molecules

Latent acetylcholinesterase in secretory vesicles isolated from adrenal medulla

A new procedure is described for the preparation of highly purified and stable secretory vesicles from adrenal medulla. Two forms of acetylcholinesterase, a membrane bound form as well as a soluble form, were found within these vesicles. The secretory vesicles, isolated by differential centrifugation, were further purified on a continuous isotonic Percoll™ gradient. In this way, secretory vesicles were separated from mitochondrial, microsomal and cell membrane contamination. The secretory vesicles recovered from the gradient contained an average of 2.26 μmol adrenalin/mg protein. On incubation for 30 min at 37°C in media differing in ionic strength, pH, Mg2+ and Ca2+ concentration, the vesicles released less than 20% of total adrenalin. Acetylcholinesterase could hardly be detected in the secretory vesicle fraction when assayed in isotonic media. However, in hypotonic media (<400 mosmol/kg) or in Triton X-100 (0.2% final concentration) acetylcholinesterase activity was markedly higher. During hypotonic treatment or when secretory vesicles were specifically lyzed with 2 mM Mg2+ and 2 mM ATP, adrenalin as well as part of acetylcholinesterase was released from the vesicular content. On polyacrylamide gel electrophoresis this soluble enzyme exhibited the same electrophoretic mobility as the enzyme released into the perfusate from adrenal glands upon stimulation. In addition to the soluble enzyme a membrane bound form of acetylcholinesterase exists within secretory vesicles, which sediments with the secretory vesicle membranes and exhibits a different electrophoretic mobility compared to the soluble enzyme. It is concluded, that the soluble enzyme found within isolated secretory vesicles is secreted via exocytosis, whilst the membrane-bound form is transported to the cell membrane during this process, contributing to the biogenesis of the cell membrane

Sterol 3β-glucosyltransferase biocatalysts with a range of selectivities, including selectivity for testosterone

The main objectives of this work were to characterise a range of purified recombinant sterol 3β-glucosyltransferases and show that rational sampling of the diversity that exists within sterol 3β-glucosyltransferase sequence space can result in a range of enzyme selectivities. In our study the catalytically active domain of the Saccharomyces cerevisiae 3β-glucosyltransferase was used to mine putative sterol 3β-glucosyltransferases from the databases. Selected diverse sequences were expressed in and purified from Escherichia coli and shown to have different selectivities for the 3β-hydroxysteroids ergosterol and cholesterol. Surprisingly, three enzymes were also selective for testosterone, a 17β-hydroxysteroid. This study therefore reports for the first time sterol 3β-glucosyltransferases with selectivity for both 3β- and 17β-hydroxysteroids and is also the first report of recombinant 3β-glucosyltransferases with selectivity for steroids with a hydroxyl group at positions other than C-3. These enzymes could therefore find utility in the pharmaceutical industry for the green synthesis of a range of glycosylated compounds of medicinal interest

Human complement factor H. Two factor H proteins are derived from alternatively spliced transcripts

The human complement factor H is an important component in the control of the alternative pathway of complement activation. We have previously shown that at least three factor H homologous mRNA species of 4.3 kb, 1.8 kb and 1.4 kb in length are constitutively expressed in human liver. In addition, several factor Hrelated proteins have been detected in human sera using antibodies directed against the classical human factor H glycoprotein of 150 kDa.The structure of the additional polypeptides has not been shown so far. Circumstantial evidence suggests that the 1.8-kb mRNA might encode the 43-kDa factor H-like polypeptide. Here we report the isolation, characterization and eukaryotic expression of the first full-length cDNA representing the major 4.3-kb mRNA and the 1.8-kb mRNA of human factor H. We show that the 4.3-kb transcript encodes the 150-kDa-factor H glycoprotein and the 1.8-kb mRNA the 43-kDa factorH polypeptide. The identity of the two cDNA in a region of 1400 nucleotides suggests that the two factor H-related transcripts are derived from one gene by a process of alternative splicing

Extracellular aspartic protease SAP2 of Candida albicans yeast cleaves human kininogens and releases proinflammatory peptides, Met-Lys-bradykinin and des-Arg(9)-Met-Lys-bradykinin

Bradykinin-related peptides, universal mediators of inflammation collectively referred to as the kinins, are often produced in excessive amounts during microbial infections. We have recently shown that the yeast Candida albicans, the major fungal pathogen to humans, can exploit two mechanisms to enhance kinin levels at the sites of candidial infection, one depending on adsorption and activation of the endogenous kinin-generating system of the host on the fungal cell wall and the other relying on cleavage of kinin precursors, the kininogens, by pathogen-secreted proteases. This work aimed at assigning this kininogenase activity to the major secreted aspartic protease of C. albicans (SAP2). The purified SAP2 was shown to cleave human kininogens, preferably the low molecular mass form (LK) and optimally in an acidic environment (pH 3.5-4.0), and to produce two kinins, Met-Lys-bradykinin and its derivative, {[}Hydroxyproline(3)]-Met-Lys-bradykinin, both of which are capable of interacting with cellular bradykinin receptors of the B2 subtype. Additionally, albeit with a lower yield, des-Arg(9)-Met-Lys-bradykinin, an effective agonist of B1-subtype receptors, was released. The pathophysiological potential of these kinins and des-Arg-kinin was also proven by presenting their ability to stimulate human promonocytic cells U937 to release proinflammatory interleukin 1 beta (IL-1 beta) and IL-6