Die Voortrekker-Monument

Die Eeufeesjaar is vir die Afrikaner ’n tydperk van besieling. Nog nooit sedert die ontstaan van ons volk het een enkele gebeurtenis soveel nasietrots gewek as die honderdjarige herdenking van die Groot Trek. Vir die eerste keer in ons geskiedenis voel ons ons nie meer Kapenaars, Vrystaters, Natalers, en Transvalers nie, maar Afrikaners, saamgesnoer deur die tradisies van ’n selfstandige kultuurvolk. Wanneer die klimaks van die Ossewatrek met die hocksteenlegging van die Voortrekker-Monument bereik word, sal die besieling nie uitsterf nie, die krag wat geskep is sal bly voortgroei tot ’n onweerstaanbare mag. Die Afrikaner sal homself vind, en as die Monument na sowat vyf jaar onthul word, sal die saad wat in hierdie jaar gesaai is, tot voile rypheid gekom het. Dan sal die Monument self tot die volk spreek; intussen egter, is dit wenslik, nee noodsaaklik selfs, om die Monument aan die Afrikaners te verklaar, om ‘n uiteensetting te gee van die noodsaaklikheid van so ’n Monument, sowel as om die motief te verduidelik wat as inspirasie gedien het vir die ontwerpdaar van

Design and application of N,Nʹ-diamidocarbenes: expanding the constraints of stable carbene chemistry.

Strategic incorporation of carbonyl groups into an N-heterocyclic carbene (NHC) scaffold via rapid and high-yielding methodologies culminating in classical deprotonation methods or the novel reduction of geminal dichlorides afforded stable and relatively electrophilic diamidocarbenes (DACs). Similar to transient, electrophilic carbenes and unlike NHCs, DACs underwent a variety of transformations with a broad range of small molecules including the unprecedented reversible coupling of carbon monoxide, metal-free transfer hydrogenations, and insertion into pnictogen-H bonds. Additionally, formal [2+1] cycloadditions were observed between DACs and a variety of alkenes, aldehydes, alkynes, and nitriles including the first examples between an isolable carbene and alkynes or electron-rich alkenes. DACs also effected the only uncatalyzed intermolecular C–H insertions of a stable carbene with non-acidic substrates to date. Beyond unprecedented reactivity scope, hydrolysis of the resultant diamidocyclopropenes or cyclopropanes afforded cyclopropenones or linear carboxylic acids. The latter constituted the formal, metal- and CO-free anti-Markovnikov hydrocarboxylation of an olefin and illustrated the ability of DACs to function as a reactive synthetic equivalent of carbon monoxide. Mechanistically, DACs were found to function primarily as nucleophiles in cycloadditions with alkynes, aldehydes, and various styrene derivatives and as an electrophile in the activation of primary amines. Thus, DACs may best be considered as ambiphiles which alters the paradigm of stable carbenes functioning exclusively as nucleophilic species. The reversibility of numerous small molecule-DAC interactions under mild conditions also suggested the potential of these systems in catalytic applications wherein dynamic association and release assume critical roles. Regardless, the reactivity associated with transient, electrophilic carbenes was largely achieved within a stable carbene scaffold and is envisioned to aid and influence the design and application of stable carbenes.Chemistr

A Translation of the Minutes of the First Reformed Church of Holland, Michigan

A translation of the minutes of the First Reformed Church of Holland, Michigan, of the stormy session when the congregation (males only at that time) voted to leave the denomination of the Reformed Church in America.https://digitalcommons.hope.edu/vrp_1880s/1005/thumbnail.jp

The complexity of cognitive structure in relation to scholastic achievement.

Thesis (M.A.)-University of Natal, Durban, 1973.This study is concerned with patterns of information search and utilisation, and the effect these have on the areas of academic interest and the level of achievement within these areas as a result a fit between the individual and his environment. In particular, the study deals with the scholar's level of cognitive complexity as described by Harvey, Hunt and Schroder (1961) and the effect such complexity level has upon subject preference in the final school year and whether this in turn effects the level of competence and achievement of the pupil. It will be argued that individual differences in cognitive style or information processing strategies act as moderator variables, resulting in a preference for and relative success in some rather than other domains of intellectual activity. A distinction is drawn between styles that encourage the consideration of a fairly wide range of variables, and those that favour a more restricted range in any given situation. Furthermore, it is argued that the natural sciences, in nature and educational aims, favour individuals with restricted styles, while the arts and humanities favour the "broader" cognitive styles. A link is drawn between these styles and the complexity of the individual's cognitive structure, and the hypothesis is tested that a preference for and success in the arts as against the sciences is a function of an increase in complexity. Results in support of the hypothesis is presented and implications of the findings are discussed

Analysis of virion associated host proteins in vesicular stomatitis virus using a proteomics approach

<p>Abstract</p> <p>Background</p> <p>Vesicular stomatitis virus (VSV) is the prototypic rhabdovirus and the best studied member of the order <it>Mononegavirales</it>. There is now compelling evidence that enveloped virions released from infected cells carry numerous host (cellular) proteins some of which may play an important role in viral replication. Although several cellular proteins have been previously shown to be incorporated into VSV virions, no systematic study has been done to reveal the host protein composition for virions of VSV or any other member of <it>Mononegavirales</it>.</p> <p>Results</p> <p>Here we used a proteomics approach to identify cellular proteins within purified VSV virions, thereby creating a "snapshot" of one stage of virus/host interaction that can guide future experiments aimed at understanding molecular mechanisms of virus-cell interactions. Highly purified preparations of VSV virions from three different cell lines of human, mouse and hamster origin were analyzed for the presence of cellular proteins using mass spectrometry. We have successfully confirmed the presence of several previously-identified cellular proteins within VSV virions and identified a number of additional proteins likely to also be present within the virions. In total, sixty-four cellular proteins were identified, of which nine were found in multiple preparations. A combination of immunoblotting and proteinase K protection assay was used to verify the presence of several of these proteins (integrin β1, heat shock protein 90 kDa, heat shock cognate 71 kDa protein, annexin 2, elongation factor 1a) within the virions.</p> <p>Conclusion</p> <p>This is, to our knowledge, the first systematic study of the host protein composition for virions of VSV or any other member of the order <it>Mononegavirales</it>. Future experiments are needed to determine which of the identified proteins have an interaction with VSV and whether these interactions are beneficial, neutral or antiviral with respect to VSV replication. Identification of host proteins-virus interactions beneficial for virus would be particularly exciting as they can provide new ways to combat viral infections via control of host components.</p

Analysis of vaccinia virus temperature-sensitive I7L mutants reveals two potential functional domains

As an approach to initiating a structure-function analysis of the vaccinia virus I7L core protein proteinase, a collection of conditional-lethal mutants in which the mutation had been mapped to the I7L locus were subjected to genomic sequencing and phenotypic analyses. Mutations in six vaccinia virus I7L temperature sensitive mutants fall into two groups: changes at three positions at the N-terminal end between amino acids 29 and 37 and two different substitutions at amino acid 344, near the catalytic domain. Regardless of the position of the mutation, mutants at the non-permissive temperature failed to cleave core protein precursors and had their development arrested prior to core condensation. Thus it appears that the two clusters of mutations may affect two different functional domains required for proteinase activity

A role for DNA-dependent activator of interferon regulatory factor in the recognition of herpes simplex virus type 1 by glial cells

<p>Abstract</p> <p>Background</p> <p>The rapid onset of potentially lethal neuroinflammation is a defining feature of viral encephalitis. Microglia and astrocytes are likely to play a significant role in viral encephalitis pathophysiology as they are ideally positioned to respond to invading central nervous system (CNS) pathogens by producing key inflammatory mediators. Recently, DNA-dependent activator of IFN regulatory factor (DAI) has been reported to function as an intracellular sensor for DNA viruses. To date, the expression and functional role of DAI in the inflammatory responses of resident CNS cells to neurotropic DNA viruses has not been reported.</p> <p>Methods</p> <p>Expression of DAI and its downstream effector molecules was determined in C57BL/6-derived microglia and astrocytes, either at rest or following exposure to herpes simplex virus type 1 (HSV-1) and/or murine gammaherpesvirus-68 (MHV-68), by immunoblot analysis. In addition, such expression was studied in ex vivo microglia/macrophages and astrocytes from uninfected animals or mice infected with HSV-1. Inflammatory cytokine production by glial cultures following transfection with a DAI specific ligand (B-DNA), or following HSV-1 challenge in the absence or presence of siRNA directed against DAI, was assessed by specific capture ELISA. The production of soluble neurotoxic mediators by HSV-1 infected glia following DAI knockdown was assessed by analysis of the susceptibility of neuron-like cells to conditioned glial media.</p> <p>Results</p> <p>We show that isolated microglia and astrocytes constitutively express DAI and its effector molecules, and show that such expression is upregulated following DNA virus challenge. We demonstrate that these resident CNS cells express DAI <it>in situ</it>, and show that its expression is similarly elevated in a murine model of HSV-1 encephalitis. Importantly, we show B-DNA transfection can elicit inflammatory cytokine production by isolated glial cells and DAI knockdown can significantly reduce microglial and astrocyte responses to HSV-1. Finally, we demonstrate that HSV-1 challenged microglia and astrocytes release neurotoxic mediators and show that such production is significantly attenuated following DAI knockdown.</p> <p>Conclusions</p> <p>The functional expression of DAI by microglia and astrocytes may represent an important innate immune mechanism underlying the rapid and potentially lethal inflammation associated with neurotropic DNA virus infection.</p

Structure-function analysis of the vaccinia virus I7L proteinase

Vaccinia virus is the prototypic member of the Orthopoxvirus genus. It undergoes a complex replication process where a key step in the transition from immature virion to intracellular mature virion is the cleavage of the major core protein precursors. The product of the I7L open reading frame (ORF) is a protein with an apparent molecular weight of 47kDa and has been shown to be responsible for these cleavages. However, relatively little is known about the biochemistry of the cleavage reaction, the structural features which allow I7L to direct regulated catalysis, or mechanisms by which I7L activity is regulated. As one approach to answering these questions, a phenotypic analysis was conducted on a collection of six conditional-lethal mutants in which the mutation had been mapped to the I7L locus. Genomic sequencing showed all the mutants have single amino acid substitutions within the I7L ORF. The mutations fall into two groups: changes at three positions at the N-terminus between amino acids 29 and 37 and two different substitutions at amino acid 344, near the catalytic cysteine. Two of the mutants had the exact same change. Regardless of where the mutation occurred, mutants at the non-permissive temperature failed to cleave core protein precursors and had their development arrested after immature virion assembly but prior to core condensation. Thus, we propose that the two clusters of mutations may affect two different functional domains required for proteinase activity. In a second approach, by using a combination of immunoprecipitation, immunoblotting and mass spectrometry, we showed that I7L can form a homodimer and be cleaved into a product with a molecular weight of approximately 40kDa. Mass spectrometry analysis of proteins that co-immunoprecipitated with I7L failed to provide leads on potential I7L cofactors. I7L proteins with mutations matching those in the temperature-sensitive mutants described above were capable of forming dimers and being cleaved. Thus the mechanism by which the N-terminal mutants obtain their conditional-lethal phenotype remains unknown. Taken together, this suggests several possible new models for the regulation of I7L

APOBEC3 Mediates Resistance to Oncolytic Viral Therapy

Tumor cells frequently evade applied therapies through the accumulation of genomic mutations and rapid evolution. In the case of oncolytic virotherapy, understanding the mechanisms by which cancer cells develop resistance to infection and lysis is critical to the development of more effective viral-based platforms. Here, we identify APOBEC3 as an important factor that restricts the potency of oncolytic vesicular stomatitis virus (VSV). We show that VSV infection of B16 murine melanoma cells upregulated APOBEC3 in an IFN-β-dependent manner, which was responsible for the evolution of virus-resistant cell populations and suggested that APOBEC3 expression promoted the acquisition of a virus-resistant phenotype. Knockdown of APOBEC3 in B16 cells diminished their capacity to develop resistance to VSV infection in vitro and enhanced the therapeutic effect of VSV in vivo. Similarly, overexpression of human APOBEC3B promoted the acquisition of resistance to oncolytic VSV both in vitro and in vivo. Finally, we demonstrate that APOBEC3B expression had a direct effect on the fitness of VSV, an RNA virus that has not previously been identified as restricted by APOBEC3B. This research identifies APOBEC3 enzymes as key players to target in order to improve the efficacy of viral or broader nucleic acid-based therapeutic platforms

South African Ebola diagnostic response in Sierra Leone : a modular high biosafety field laboratory

BACKGROUND : In August 2014, the National Institute for Communicable Diseases (NICD) in South Africa established a modular high-biosafety field Ebola diagnostic laboratory (SA FEDL) near Freetown, Sierra Leone in response to the rapidly increasing number of Ebola virus disease (EVD) cases. METHODS AND FINDINGS : The SA FEDL operated in the Western Area of Sierra Leone, which remained a ªhotspotº of the EVD epidemic for months. The FEDL was the only diagnostic capacity available to respond to the overwhelming demand for rapid EVD laboratory diagnosis for several weeks in the initial stages of the EVD crisis in the capital of Sierra Leone. Furthermore, the NICD set out to establish local capacity amongst Sierra Leonean nationals in all aspects of the FEDL functions from the outset. This led to the successful hand-over of the FEDL to the Sierra Leone Ministry of Health and Sanitation in March 2015. Between 25 August 2014 and 22 June 2016, the laboratory tested 11,250 specimens mostly from the Western Urban and Western Rural regions of Sierra Leone, of which 2,379 (21.14%) tested positive for Ebola virus RNA. CONCLUSIONS : he bio-safety standards and the portability of the SA FEDL, offered a cost-effective and practical alternative for the rapid deployment of a field-operated high biocontainment facility. The SA FEDL teams demonstrated that it is highly beneficial to train the national staff in the course of formidable disease outbreak and accomplished their full integration into all operational and diagnostic aspects of the laboratory. This initiative contributed to the international efforts in bringing the EVD outbreak under control in Sierra Leone, as well as capacitating local African scientists and technologists to respond to diagnostic needs that might be required in future outbreaks of highly contagious pathogens.S1 Video. ªHotº processing of Ebola clinical specimens, PPE and decontamination procedures in South African modular, field-operated biocontainment facility in Sierra Leone.Janusz T Paweska was supported by funding from National Research Foundation and the Global Disease Detection Programmehttp://www.plosntds.orgam2017Microbiology and Plant Patholog