Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E )-1-(2-benzylidene-1-methylhydrazinyl)-3- hydroxy-1-oxopropan-2-yl]carbamates

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Mutations in the Schmallenberg virus Gc glycoprotein facilitate cellular protein synthesis shutoff and restore pathogenicity of NSs deletion mutants in mice

Serial passage of viruses in cell culture has been traditionally used to attenuate virulence and identify determinants of viral pathogenesis. In a previous study, we found that a strain of Schmallenberg virus (SBV) serially passaged in tissue culture (termed SBVp32) unexpectedly displayed increased pathogenicity in suckling mice compared to wild type SBV. In this study, we mapped the determinants of SBVp32 virulence to the viral genome M segment. SBVp32 virulence is associated with the capacity of this virus to reach higher titers in the brains of experimentally infected suckling mice. We also found that the Gc glycoprotein, encoded by the M segment of SBVp32, facilitates host cell protein shutoff in vitro. Interestingly, while the M segment of SBVp32 is a virulence factor, we found that the S segment of the same virus confers by itself an attenuated phenotype to wild type SBV as has lost the ability to block the innate immune system of the host. Single mutations present in the Gc glycoprotein of SBVp32 are sufficient to compensate both the attenuated phenotype of the SBVp32 S segment and the attenuated phenotype of NSs deletion mutants. Our data also indicate that the SBVp32 M segment does not act as an IFN antagonist. Therefore SBV mutants can retain pathogenicity even when they are unable to fully control the production of IFN by the infected cells. Overall, this study suggests that the viral glycoprotein of orthobunyaviruses can compensate, at least in part, the function of NSs. In addition, we also provide evidence that the induction of total cellular protein shutoff by SBV is determined by multiple viral proteins while the ability to control the production of IFN maps to the NSs protein. Importance The identification of viral determinants of pathogenesis is key to the development of prophylactic and interventions measures. In this study we found that the bunyavirus Gc glycoprotein is a virulence factor. Importantly, we show that mutations in the Gc glycoprotein can restore pathogenicity of attenuated mutants resulting from deletions or mutations in the non-structural protein NSs. Our findings highlight the fact that careful consideration should be taken when designing live attenuated vaccines based on deletions of non-structural proteins since single mutations in the viral glycoproteins appear to revert attenuated mutants to virulent phenotypes

4-aminopyridyl-based lead compounds targeting CYP51 prevent spontaneous parasite relapse in a chronic model and improve cardiac pathology in an acute model of Trypanosoma cruzi infection.

BackgroundChagas disease, caused by the protozoan Trypanosoma cruzi, is the leading cause of heart failure in Latin America. The clinical treatment of Chagas disease is limited to two 60 year-old drugs, nifurtimox and benznidazole, that have variable efficacy against different strains of the parasite and may lead to severe side effects. CYP51 is an enzyme in the sterol biosynthesis pathway that has been exploited for the development of therapeutics for fungal and parasitic infections. In a target-based drug discovery program guided by x-ray crystallography, we identified the 4-aminopyridyl-based series of CYP51 inhibitors as being efficacious versus T.cruzi in vitro; two of the most potent leads, 9 and 12, have now been evaluated for toxicity and efficacy in mice.Methodology/principal findingsBoth acute and chronic animal models infected with wild type or transgenic T. cruzi strains were evaluated. There was no evidence of toxicity in the 28-day dosing study of uninfected animals, as judged by the monitoring of multiple serum and histological parameters. In two acute models of Chagas disease, 9 and 12 drastically reduced parasitemia, increased survival of mice, and prevented liver and heart injury. None of the compounds produced long term sterile cure. In the less severe acute model using the transgenic CL-Brenner strain of T.cruzi, parasitemia relapsed upon drug withdrawal. In the chronic model, parasitemia fell to a background level and, as evidenced by the bioluminescence detection of T. cruzi expressing the red-shifted luciferase marker, mice remained negative for 4 weeks after drug withdrawal. Two immunosuppression cycles with cyclophosphamide were required to re-activate the parasites. Although no sterile cure was achieved, the suppression of parasitemia in acutely infected mice resulted in drastically reduced inflammation in the heart.Conclusions/significanceThe positive outcomes achieved in the absence of sterile cure suggest that the target product profile in anti-Chagasic drug discovery should be revised in favor of safe re-administration of the medication during the lifespan of a Chagas disease patient. A medication that reduces parasite burden may halt or slow progression of cardiomyopathy and therefore improve both life expectancy and quality of life

Different packing motifs of isomeric (E)-N1-(halophenylmethylidene)-N-methyl-2-(thiophen-2-yl)-acetohydrazides controlled by C—HO interactions

We thank the EPSRC National Crystallography Service (University of Southampton) for the X-ray data collectionsPeer reviewedPublisher PD

Defective DNA base excision repair in brain from individuals with Alzheimer's disease and amnestic mild cognitive impairment

Oxidative stress is thought to play a role in the pathogenesis of Alzheimer's disease (AD) and increased oxidative DNA damage has been observed in brain tissue from AD patients. Base excision repair (BER) is the primary DNA repair pathway for small base modifications such as alkylation, deamination and oxidation. In this study, we have investigated alterations in the BER capacity in brains of AD patients. We employed a set of functional assays to measure BER activities in brain tissue from short post-mortem interval autopsies of 10 sporadic AD patients and 10 age-matched controls. BER activities were also measured in brain samples from 9 amnestic mild cognitive impairment (MCI) subjects. We found significant BER deficiencies in brains of AD patients due to limited DNA base damage processing by DNA glycosylases and reduced DNA synthesis capacity by DNA polymerase β. The BER impairment was not restricted to damaged brain regions and was also detected in the brains of amnestic MCI patients, where it correlated with the abundance of neurofibrillary tangles. These findings suggest that BER dysfunction is a general feature of AD brains which could occur at the earliest stages of the disease. The results support the hypothesis that defective BER may play an important role in the progression of AD

Comparative analysis of genome-encoded viral sequences reveals the evolutionary history of flavivirids (family Flaviviridae)

The flavivirids (family Flaviviridae) are a group of positive-strand RNA viruses that pose serious risks to human and animal health on a global scale. Here we use flavivirid-derived DNA sequences, identified in animal genomes, to reconstruct the long-term evolutionary history of family Flaviviridae. We demonstrate that flavivirids are >100 million years old and show that this timing can be combined with dates inferred from co-phyletic analysis to produce a cohesive overview of their evolution, distribution and diversity wherein the main flavivirid subgroups originate in early animals and broadly co-diverge with major animal phyla. In addition, we reveal evidence that the ‘classical flaviviruses’ of vertebrates, most of which are transmitted via blood-feeding arthropod vectors, originally evolved in hematophagous arachnids and later acquired the capacity to be transmitted by insects. Our findings imply that the biological properties of flavivirids have been acquired gradually over the course of animal evolution. Thus, broad-scale comparative analysis will likely reveal fundamental insights into their biology. We therefore published our results via an open, extensible, database (Flavivirid-GLUE), which we constructed to facilitate the wider utilisation of genomic data and evolution-related domain knowledge in flavivirid research

Livestock integration into soybean systems improves long‐term system stability and profts without compromising crop yields

Climate models project greater weather variability over the coming decades. High yielding systems that can maintain stable crop yields under variable environmental scenarios are critical to enhance food security. However, the efect of adding a trophic level (i.e. herbivores) on the long-term stability of agricultural systems is not well understood. We used a 16-year dataset from an integrated soybean- beef cattle experiment to measure the impacts of grazing on the stability of key crop, pasture, animal and whole-system outcomes. Treatments consisted of four grazing intensities (10, 20, 30 and 40 cm sward height) on mixed black oat (Avena strigosa) and Italian ryegrass (Lolium multiforum) pastures and an ungrazed control. Stability of both human-digestible protein production and proftability increased at moderate to light grazing intensities, while over-intensifcation or absence of grazing decreased system stability. Grazing did not afect subsequent soybean yields but reduced the chance of crop failure and fnancial loss in unfavorable years. At both lighter and heavier grazing intensities, tradeofs occurred between the stability of herbage production and animal live weight gains. We show that ecological intensifcation of specialized soybean systems using livestock integration can increase system stability and proftability, but the probability of win–win outcomes depends on management

Different packing motifs mediated by weak inter­actions and polymorphism in the crystal structures of five 2-(benzyl­­idene)benzosuberone derivatives

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Different weak interactions in the crystals of three isomeric (E)-N-methyl-N0-(nitrobenzylidene)- 2-(thiophen-2-yl)acetohydrazides

We thank the EPSRC National Crystallography Service (University of Southampton) for X-ray data collection.Peer reviewedPublisher PD