The thermal stability of the tryptic fragment of bovine microsomal cytochrome b5 and a variant containing six additional residues

AbstractThermally induced denaturation has been measured for both oxidised and reduced forms of the tryptic fragment or bovine microsomal cytochrome b5 using spectrophotometric methods. In the oxidised state, the tryptic fragment of cytochrome b5 (Ala7-Lys90) denatures in a single cooperative transition with a midpoint temperature (Tm) of ∼ 67°C (pH 7.0). The reduced form of the tryptic fragment of cytochrome b5 shows a higher transition temperature of ∼ 73°C at pH 7.0 and this is reflected in the values of ΔHm, ΔSm, and Δ(ΔG) of ∼ 310kJ · mol−1, 900J · mol−1 · K−1 and 5 kJ · mol−1. Increased thermal stability is demonstrated for a variant protein that contains the first 90 amino acid residues of cytochrome b5. These novel increases in stability are observed in both redox states and result from the presence of six additional residues at the amino-terminus. The two forms of cytochrome b5 do not differ significantly in structure with the results suggesting that the reorganisation energy (λ) of the variant protein, as measured indirectly from redox-linked differences in conformational stability, is small. Consequently the reported subtle differences in reactivity between variants of cytochrome b5 may result from the presence of additional N-terminal residues on the surface of the protein

Contribución de los modelos murino y primate al estudio de las enfermedades por arenavirus y fiebres hemorrágicas

ABSTRACT: This manuscript is an inedited part of my PhD dissertation, based on historical and recent findings on animal models, that was presented as part of the requirements to fulfill the conditions to become a philosophical doctor on Veterinary Sciences at the University of Wisconsin on October of 2003.The current mini-review written on a free-version style, underlines some of the cornerstones of immunology as a science, understood thanks to the use of the Lymphocytic Choriomeningitis virus (LCMV) experimentally and naturally infected mouse model. It should suffice to say that there have been two Nobel prices of Medicine for discoveries made through the employment of this animal model, in order to recognize the right importance to it. In addition, several laboratories, Dr. Salvato´s among them, have also employed the LCMV-infected Rhesus monkey model as a tool to unravel the mysteries of arenaviral hemorrhagic fever, and particularly the physiopathology of Lassa disease in humans. Here I show some of the knowledge generated through the study of both animal infections.RESUMEN: El siguiente manuscrito, es un capítulo inédito de mi tesis doctoral, basado en hallazgos históricos y recientes sobre modelos animales, que fue presentado como parte de los requisitos para obtener el título de Ph.D. en Ciencias veterinarias en la Universidad de Wisconsin, en Octubre de 2003.La actual minirevisión escrita en estilo de versión libre, subraya algunas de las piedras angulares de la inmunología como ciencia, entendidas gracias al uso del modelo murino infectado natural y experimentalmente con el virus de Coriomeningitis Linfocítica (LCMV). Sería suficiente mencionar que han existido dos premios Nóbel de Medicina por descubrimientos realizados a través del empleo de este modelo animal, para reconocer la real importancia del mismo. Adicionalmente, varios laboratorios, el de la Dra. Salvato entre ellos, también han empleado el modelo del mono Rhesus como un instrumento para desvelar los misterios de las fiebres hemorrágicas por arenavirus, y particularmente la fisiopatología de la enfermedad de Lassa en humanos. Aquí yo muestro algo del conocimiento generado a través del estudio de ambas infecciones animales

Imaging bond order near non-magnetic impurities in square lattice antiferromagnets

We study the textures of generalized "charge densities" (scalar objects invariant under time reversal), in the vicinity of non-magnetic impurities in square-lattice quantum anti-ferromagnets, by order parameter field theories. Our central finding is the structure of the "vortex" in the generalized density wave order parameter centered at the non-magnetic impurity. Using exact numerical data from quantum Monte Carlo simulations on an antiferromagnetic spin model, we are able to verify the results of our field theoretic study. We extend our phenomenological approach to the period-4 bond-centered density wave found in the underdoped cuprates.Comment: 4 pages, 4 figure

Operationalizing Cooperative Research for Infectious Disease Surveillance: Lessons Learned and Ways Forward.

The current COVID-19 pandemic demonstrates the need for urgent and on-demand solutions to provide diagnostics, treatment and preventative measures for infectious disease outbreaks. Once solutions are developed, meeting capacities depends on the ability to mitigate technical, logistical and production issues. While it is difficult to predict the next outbreak, augmenting investments in preparedness, such as infectious disease surveillance, is far more effective than mustering last-minute response funds. Bringing research outputs into practice sooner rather than later is part of an agile approach to pivot and deliver solutions. Cooperative multi- country research programs, especially those funded by global biosecurity programs, develop capacity that can be applied to infectious disease surveillance and research that enhances detection, identification, and response to emerging and re-emerging pathogens with epidemic or pandemic potential. Moreover, these programs enhance trust building among partners, which is essential because setting expectation and commitment are required for successful research and training. Measuring research outputs, evaluating outcomes and justifying continual investments are essential but not straightforward. Lessons learned include those related to reducing biological threats and maturing capabilities for national laboratory diagnostics strategy and related health systems. Challenges, such as growing networks, promoting scientific transparency, data and material sharing, sustaining funds and developing research strategies remain to be fully resolved. Here, experiences from several programs highlight successful partnerships that provide ways forward to address the next outbreak

Climate change and infectious disease: A prologue on multidisciplinary cooperation and predictive analytics

Climate change impacts global ecosystems at the interface of infectious disease agents and hosts and vectors for animals, humans, and plants. The climate is changing, and the impacts are complex, with multifaceted effects. In addition to connecting climate change and infectious diseases, we aim to draw attention to the challenges of working across multiple disciplines. Doing this requires concentrated efforts in a variety of areas to advance the technological state of the art and at the same time implement ideas and explain to the everyday citizen what is happening. The world's experience with COVID-19 has revealed many gaps in our past approaches to anticipating emerging infectious diseases. Most approaches to predicting outbreaks and identifying emerging microbes of major consequence have been with those causing high morbidity and mortality in humans and animals. These lagging indicators offer limited ability to prevent disease spillover and amplifications in new hosts. Leading indicators and novel approaches are more valuable and now feasible, with multidisciplinary approaches also within our grasp to provide links to disease predictions through holistic monitoring of micro and macro ecological changes. In this commentary, we describe niches for climate change and infectious diseases as well as overarching themes for the important role of collaborative team science, predictive analytics, and biosecurity. With a multidisciplinary cooperative “all call,” we can enhance our ability to engage and resolve current and emerging problems

Apoptosis-Specific Protein (ASP) Identified in Apoptotic Xenopus Thymus Tumor Cells

A novel apoptosis-specific protein (ASP) has recently been identified in the cytoplasm of apoptotic mammalian cells. This paper investigates whether ASP is found in Xenopus thymus tumor-derived lymphoid cell lines undergoing apoptosis and also in apoptotic, nontransformed splenocytes. Cultured Xenopus tumor lymphoid cells induced to undergo, apoptosis by serum deprivation or treatment with the calcium ionophore, ionomycin, displayed altered morphology typical of apoptotic cells, as judged by flow cytometric light-scatter characteristics and by fluorescence microscopy of acridine-orange-stained cells. Flow cytometry of permeabilized cells and fluorescence microscopy of acetone-fixed cytospins revealed that apoptotic Xenopus tumor cells, especially those displaying loss or condensation of DNA, displayed increased expression of epitopes recognized by a rabbit polyclonal antibody against ASP. Flow cytometry confirmed that ASP is also expressed in splenocytes induced to apoptose by culture in ionomycin or following concanavalin A stimulation. No increased expression of ASP was seen when lymphoid tumor cells or splenocytes were induced into necrosis by overdose with the antifungal agent amphotericin B. Western blotting with antibody against ASP identified the emergence of several protein bands in cell lysates from apoptotic, but not necrotic, Xenopus tumor cells. The new and simple methodology for identifying apoptotic cells described here is likely to be of value to those studying immune system development and associated programmed cell death in Xenopus

Prevalence of Antibodies against Hantaviruses in Serum and Saliva of Adults Living or Working on Farms in Yorkshire, United Kingdom

We acknowledge Clement and colleagues for their comments [1] on our paper [2]. We agree that many controversies are being discussed by the hantavirus community, particularly surrounding the interpretation of serological results and the designation of new species and strains. Within this setting, we are grateful for the opportunity to respond to the key factual and methodological points raised by Clements et al. [...

Comparison of Zaire ebolavirus realtime RT-PCRs targeting the nucleoprotein gene

In last five years, the Africa has faced two outbreaks of Zaire ebolavirus. These outbreaks have been the largest so far, and latest outbreak is still ongoing and affecting the Democratic Republic of the Congo. We tested in parallel three different Zaire ebolavirus (EBOV) realtime RT-PCRs targeting the nucleoprotein gene (EBOV NP-RT-qPCRs) described by Trombley et al. (2010); Huang et al. (2012) and Weidmann et al. (2004). These assays are used regularly in diagnostic laboratories. The limit of detection (LOD), intra-assay repeatability using different matrixes, sensitivity and specificity were determined. In addition, the primers and probes were aligned with the sequences available in ongoing and past outbreaks in order to check the mismatches. The specificity of all three EBOV NP-RT-qPCRs were excellent (100 %), and LODs were under or 10 copies per PCR reaction. Intra-assay repeatability was good in all assays, however the Ct-values were bit higher using the EDTA-blood based matrix. All of the primers and probes in EBOV NP-RT-qPCR assays have one or more mismatches in the probes and primers when the 2267 Zaire EBOV NP sequences, including strains Ituri from DRC outbreak (year 2018), was aligned. The EBOV strain of Bikoro (year 2018) circulating in DRC was 100 % match in Trombley and Weidmann assay, but had one mismatch in Huang assay.Peer reviewe