Mammalian Cells Engineered To Produce New Steroids

Steroids can be difficult to modify through traditional organic synthesis methods, but many enzymes regio‐ and stereoselectively process a wide variety of steroid substrates. We tested whether steroid‐modifying enzymes could make novel steroids from non‐native substrates. Numerous genes encoding steroid‐modifying enzymes, including some bacterial enzymes, were expressed in mammalian cells by transient transfection and found to be active. We made three unusual steroids by stable expression, in HEK293 cells, of the 7α‐hydroxylase CYP7B1, which was selected because of its high native product yield. These cells made 7α,17α‐dihydroxypregnenolone and 7β,17α‐dihydroxypregnenolone from 17α‐hydroxypregnenolone and produced 11α,16α‐dihydroxyprogesterone from 16α‐hydroxyprogesterone. The last two products were the result of CYP7B1‐catalyzed hydroxylation at previously unobserved sites. A Rosetta docking model of CYP7B1 suggested that these substrates’ D‐ring hydroxy groups might prevent them from binding in the same way as the native substrates, bringing different carbon atoms close to the active ferryl oxygen atom. This new approach could potentially use other enzymes and substrates to produce many novel steroids for drug candidate testing.     

Preventing Brain Injury in the Preterm Infant—Current Controversies and Potential Therapies

Preterm birth is associated with a high risk of morbidity and mortality including brain damage and cerebral palsy. The development of brain injury in the preterm infant may be influenced by many factors including perinatal asphyxia, infection/inflammation, chronic hypoxia and exposure to treatments such as mechanical ventilation and corticosteroids. There are currently very limited treatment options available. In clinical trials, magnesium sulfate has been associated with a small, significant reduction in the risk of cerebral palsy and gross motor dysfunction in early childhood but no effect on the combined outcome of death or disability, and longer-term follow up to date has not shown improved neurological outcomes in school-age children. Recombinant erythropoietin has shown neuroprotective potential in preclinical studies but two large randomized trials, in extremely preterm infants, of treatment started within 24 or 48 h of birth showed no effect on the risk of severe neurodevelopmental impairment or death at 2 years of age. Preclinical studies have highlighted a number of promising neuroprotective treatments, such as therapeutic hypothermia, melatonin, human amnion epithelial cells, umbilical cord blood and vitamin D supplementation, which may be useful at reducing brain damage in preterm infants. Moreover, refinements of clinical care of preterm infants have the potential to influence later neurological outcomes, including the administration of antenatal and postnatal corticosteroids and more accurate identification and targeted treatment of seizures.     

Effect of encapsulation with zeolite and coating with TiO2 on the thermal stability of caffeine during melt extrusion of a PET/TiO2@(zeolite/caffeine) nanocomposite

The practice of encapsulating a functional material in a thermally stable porous material displays great potential in preventing decomposition during high-temperature processing. In this study, caffeine encapsulated in zeolite was coated with TiO₂ to withstand high-temperature melt extrusion with poly(ethylene terephthalate) (PET). Two coating processes were trialed: in situ encapsulation and coating where TiO₂ precursor was added to zeolite/caffeine solution; and ex situ coating in which pre prepared zeolite/caffeine capsules were added to the TiO₂ precursor for coating. The TiO₂-coated nanocomposites were melt-extruded with PET at 285?°C. Residual amounts of caffeine confirmed the shielding effect of the TiO₂ coating during the high-temperature melt extrusion. The in situ TiO₂ coating process was more effective than the ex situ process.     

Innovative green nanocomposites based on silicate clays/lignin/natural fibres

A new type of nanocomposite based on silicate clays, lignin and natural fibres has been elaborated by shear mixing in a twin-screw extruder. Either sepiolite or organically modified montmorillonite (Org-MMT) have been chosen for being dispersed into lignin/natural fibres system. The morphological aspect of the obtained nanocomposites has been controlled by Transmission Electronic Microscopy (TEM). For sepiolite-based nanocomposites, individual needles have been observed while Org-MMT-based nanocomposites have exhibited partial delamination of silicate layers into intercalated and exfoliated nanostructures. The properties of the specimens have been studied by thermogravimetry (TGA), Dynamic Mechanical Analysis (DMA) and flexural tests. Incorporation of 2% or 5% w/w of sepiolite does not influence the mechanical and thermal behaviour compared to the reference lignin/natural fibres composite while Org-MMT-based nanocomposites have shown improved properties.     

Of Marriages and Mortgages: The Second Demographic Transition and the Relationship between Marriage and Homeownership in Sweden

Past research has established a positive relationship between transitions to marriage and transitions into ownership. This paper explores how this relationship is changing by following a population as it advances through the Second Demographic Transition. Following a rational choice model for tenure decisions, it is hypothesized that the Second Demographic Transition is likely to affect the relationship between partnership and tenure in two ways. First, the preferences for ownership unique to marriage are likely to decline. Second, the importance of an extra income, especially for men, is likely to increase. Evidence is found supporting both these assertions for the population of Gävle, Sweden, between 1975 and 1990.     

Chemical Interrogation of the Malaria Kinome

Malaria, an infectious disease caused by eukaryotic parasites of the genus Plasmodium, afflicts hundreds of millions of people every year. Both the parasite and its host utilize protein kinases to regulate essential cellular processes. Bioinformatic analyses of parasite genomes predict at least 65 protein kinases, but their biological functions and therapeutic potential are largely unknown. We profiled 1358 small‐molecule kinase inhibitors to evaluate the role of both the human and the malaria kinomes in Plasmodium infection of liver cells, the parasites' obligatory but transient developmental stage that precedes the symptomatic blood stage. The screen identified several small molecules that inhibit parasite load in liver cells, some with nanomolar efficacy, and each compound was subsequently assessed for activity against blood‐stage malaria. Most of the screening hits inhibited both liver‐ and blood‐stage malaria parasites, which have dissimilar gene expression profiles and infect different host cells. Evaluation of existing kinase activity profiling data for the library members suggests that several kinases are essential to malaria parasites, including cyclin‐dependent kinases (CDKs), glycogen synthase kinases, and phosphoinositide‐3‐kinases. CDK inhibitors were found to bind to Plasmodium protein kinase 5, but it is likely that these compounds target multiple parasite kinases. The dual‐stage inhibition of the identified kinase inhibitors makes them useful chemical probes and promising starting points for antimalarial development.     

Fluorescent Visualization of Src by Using Dasatinib‐BODIPY

Many biological experiments are not compatible with the use of immunofluorescence, genetically encoded fluorescent tags, or FRET‐based reporters. Conjugation of existing kinase inhibitors to cell‐permeable fluorophores can provide a generalized approach to develop fluorescent probes of intracellular kinases. Here, we report the development of a small molecule probe of Src through conjugation of BODIPY to two well‐established dual Src‐Abl kinase inhibitors, dasatinib and saracatinib. We show that this approach is not successful for saracatinib but that dasatinib‐BODIPY largely retains the biological activity of its parent compound and can be used to monitor the presence of Src kinase in individual cells by flow cytometry. It can also be used to track the localization of Src by fixed and live‐cell fluorescence microscopy. This strategy could enable generation of additional kinase‐specific probes useful in systems not amenable to genetic manipulation or could be used together with fluorescent proteins to enable a multiplexed assay readout.     

Probabilistic framework for evaluating food security of households in the aftermath of a disaster

For households of all income levels, and especially for those that are food insecure, food access can be threatened by natural hazards. Extreme natural hazards can disrupt critical infrastructure systems, such as the transportation or electrical power networks, damaging the roads and bridges critical for food supply chains or electrical transmission lines providing electricity for food preservation. Interdependencies among infrastructure systems within the food supply chain make it vulnerable to unanticipated and cascading consequences. Maintaining food security in the aftermath of a natural hazard challenges a community’s resilience, recovery, and social well-being. This study introduces a methodology to consider how the interconnectedness among civil infrastructure systems impacts food-security of urban inhabitants. To this end, different infrastructure systems along with their spatial distribution are modeled to evaluate the restoration of food security within a community. Food security metrics, including food availability, accessibility, and affordability, are defined and quantified to provide risk-informed decision support to policymakers in the aftermath of an extreme natural hazard. The methodology proposed herein that considers system interconnectedness and uncertainties in demand and supply can be applied to identify practical policy interventions to hasten recovery of food systems and reduce the adverse impacts of food-insecurity on a community.