Alkaloid-like Molecules for Drug Discovery

The alkaloid class of natural compounds is extensively known for their variety of biological activities. A high percentage of currently employed chemotherapeutic drugs - more than 60% for cancer are of plant origin, and many are alkaloids.[1] Synthetic compounds that display similar structures to alkaloids are known as alkaloid-like molecules. Alkaloids are commonly documented to poses pharmacological properties such as antineoplasticity and acetylcholinesterase (AChE) inhibition. The Aristotelia alkaloids (1 and 2) have a broad spectrum of biological activities,[2] several of which contain the same 3-aza-bicyclo[3.3.1]nonane core structure architecture, seen in blue in Figure 2. Figure 1: Aristotelia alkaloids, 1 and 2. As these Alkaloids are both rare and require complex isolation, it is more resourceful to generate libraries of molecules with the same core scaffold through synthetic pathways, such as the Bridging Ritter reaction.[3] Through the use of the Bridging Ritter reaction with (-)-β-pinene (3) and various nitriles, a small library of alkaloid-like molecules has been synthesized. Figure 2: The bridging Ritter reaction of (-)-β-pinene with various nitriles. AChE inhibitors are currently the front line of drugs used for relieving the symptoms of Alzheimer’s disease (AD) by restoring natural levels neurotransmitter acetylcholine, found to be low in the synapse of AD suffers.[4] All of the currently approved AChE inhibitors have severe undesirable side-effects and with the diseases mortality rate expected to increase greatly, it is imperative that more suitable drug candidates be developed. Therefore, these alkaloid-like compounds were screened for AChE inhibitory activity using The TLC bioautographic method[5] and Ellman Assay[6]. A library of 27 alkaloid-like molecules has been synthesised. The library is currently undergoing in-house anticancer testing using the MTS assay[7] against the MDA-MB-231 breast cancer cell line. External screening has revealed one series of compounds to show potent inhibition properties against MCF-7 and one inparticular to be inactive against healthy mammalian (Vero cell line) and human oral cavity carcinoma (KB) respectively. Screening against AChE showed that the current library act only as weak inhibitors but combined with molecular modeling, has provided useful SAR data to guide the synthesis of more potent hits. Of significant interest is the importance the alkene functionality plays in providing activity. The recent finding of our work will be presented in details in this presentation

Robust and stable transcriptional repression in Giardia using CRISPRi.

Giardia lamblia is a binucleate protistan parasite causing significant diarrheal disease worldwide. An inability to target Cas9 to both nuclei, combined with the lack of nonhomologous end joining and markers for positive selection, has stalled the adaptation of CRISPR/Cas9-mediated genetic tools for this widespread parasite. CRISPR interference (CRISPRi) is a modification of the CRISPR/Cas9 system that directs catalytically inactive Cas9 (dCas9) to target loci for stable transcriptional repression. Using a Giardia nuclear localization signal to target dCas9 to both nuclei, we developed efficient and stable CRISPRi-mediated transcriptional repression of exogenous and endogenous genes in Giardia. Specifically, CRISPRi knockdown of kinesin-2a and kinesin-13 causes severe flagellar length defects that mirror defects with morpholino knockdown. Knockdown of the ventral disk MBP protein also causes severe structural defects that are highly prevalent and persist in the population more than 5 d longer than defects associated with transient morpholino-based knockdown. By expressing two guide RNAs in tandem to simultaneously knock down kinesin-13 and MBP, we created a stable dual knockdown strain with both flagellar length and disk defects. The efficiency and simplicity of CRISPRi in polyploid Giardia allows rapid evaluation of knockdown phenotypes and highlights the utility of CRISPRi for emerging model systems

Synthesis and crystal structure of unexpected (1S,4R,5R,6S)-4-cyano-2,2,6-trimethyl-3-azabicyclo[3.3.1]nonan-6-yl acetate

The reaction of (-)-β-pinene with KCN under a mild bridged Ritter reaction gave (1S,5R,6S)-2,2,6-trimethyl-3-aza-bicyclo[3.3.1]non-3-en-6-yl acetate that subsequently reacted to provide an unexpected (1S,4R,5R,6S)-4-cyano-2,2,6-trimethyl-3-azabicyclo[3.3.1]nonane-6-yl acetate. The structure of the compound was determined by high-resolution mass spectrometry, and IR and NMR spectroscopy and confirmed by single crystal X-ray crystallography. The compound crystallises in the monoclinic P21 space group, with unit cell parameters a 8.6120 (17), b 7.4570 (15), c 11.189 (2) Å, and β 110.16 (3)°

Projections of coral cover and habitat change on turbid reefs under future sea-level rise

This is the final version. Available on open access from the Royal Society via the DOI in this recordData accessibility: All field datasets are available from the NERC datacentre: http://www.bgs.ac.uk/services/ngdc/accessions/index.html?simpleText=Great%20Barrier%20Reef#item76769. The model data that support the findings of this study are openly available at: https://github.com/rudyarthur/coral.Global sea-level rise (SLR) is projected to increase water depths above coral reefs. Although the impacts of climate disturbance events on coral cover and three-dimensional complexity are well documented, knowledge of how higher sea levels will influence future reef habitat extent and bioconstruction is limited. Here, we use 31 reef cores, coupled with detailed benthic ecological data, from turbid reefs on the central Great Barrier Reef, Australia, to model broad-scale changes in reef habitat following adjustments to reef geomorphology under different SLR scenarios. Model outputs show that modest increases in relative water depth above reefs (Representative Concentration Pathway (RCP) 4.5) over the next 100 years will increase the spatial extent of habitats with low coral cover and generic diversity. More severe SLR (RCP8.5) will completely submerge reef flats and move reef slope coral communities below the euphotic depth, despite the high vertical accretion rates that characterize these reefs. Our findings suggest adverse future trajectories associated with high emission climate scenarios which could threaten turbid reefs globally and their capacity to act as coral refugia from climate change.Natural Environment Research Council (NERC

Prostate cancer

The management of prostate cancer continues to evolve rapidly, with substantial advances being made in understanding the genomic landscape and biology underpinning both primary and metastatic prostate cancer. Similarly, the emergence of more sensitive imaging methods has improved diagnostic and staging accuracy and refined surveillance strategies. These advances have introduced personalised therapeutics to clinical practice, with treatments targeting genomic alterations in DNA repair pathways now clinically validated. An important shift in the therapeutic framework for metastatic disease has taken place, with metastatic-directed therapies being evaluated for oligometastatic disease, aggressive management of the primary lesion shown to benefit patients with low-volume metastatic disease, and with several novel androgen pathway inhibitors significantly improving survival when used as a first-line therapy for metastatic disease. Research into the molecular characterisation of localised, recurrent, and progressive disease will undoubtedly have an impact on clinical management. Similarly, emerging research into novel therapeutics, such as targeted radioisotopes and immunotherapy, holds much promise for improving the lives of patients with prostate cancer

Life stress and mental disorders in the South African Stress and Health study

Background. Although stressful life events (SLEs) are associated with psychopathology, the contribution from distal and proximal events and the specificity of their association with common mental disorders require further exploration. We examined the association of recent life events and past adversities to mood, anxiety, substance use and impulse control disorders in South Africa.Methods. Data were analysed from the South African Stress and Health study, a population-based study of mental disorders in a nationally representative sample of 4 351 adults. Psychiatric disorders were assessed with the Composite International Diagnostic Interview (CIDI). This included questions covering early and later SLEs (negativelife events, relationship stress, partner violence, social strain and adverse events during childhood) and various sociodemographicvariables. Logistic regression models were constructed for 3 957 respondents (2 371 female, 1 586 male) with no missing covariate data, to assess life stress and sociodemographic predictors of 12-month and lifetime disorder.Results. Recent negative life events and relationship problems were significant predictors of any 12-month disorder and any lifetime disorder. Physical partner violence predicted any lifetime disorder. There was evidence of specificity for the prediction of mood versus anxiety disorders, with childhood adversity specifically associated with mood disorders but not anxiety disorders. Single marital status was the strongest socio-demographic predictor of any 12-month and anylifetime disorder.Conclusions. Stressful life events, distal and proximal, contribute significantly and independently to the prediction of major psychiatric disorders among South Africans, underscoring the importance of screening adversities in adults with common mental disorders, and of providing appropriate adjunctive interventions

The South African Stress and Health (SASH) study: 12- month and lifetime prevalence of common mental disorders

Background. The South African Stress and Health (SASH) study is the first large-scale population-based study of common mental disorders in the country. This paper provides data on the 12-month and lifetime prevalence of these conditions.Methods. Data from a nationally representative sample of 4 351 adults were analysed. Mental disorders were assessed with the Composite International Diagnostic Interview (CIDI). An extensive survey questionnaire detailed contextual and socio-demographic factors, onset and course of mental disorders, and risk factors. Simple weighted cross-tabulation methods were used to estimate prevalence, and logistic regression analysis was used to study correlates of 12-monthand lifetime prevalence.Results. The lifetime prevalence for any disorder was 30.3%, and the most prevalent 12-month and lifetime disorders were the anxiety disorders. The Western Cape had the highest 12-month and lifetime prevalence rates, and the lowest rates were in the Northern Cape.Conclusions. The SASH study shows relatively high 12-monthand lifetime prevalence rates. These findings have significant implications for planning mental health services

Binding interface change and cryptic variation in the evolution of protein-protein interactions

Background:Physical interactions between proteins are essential for almost all biological functions and systems. To understand the evolution of function it is therefore important to understand the evolution of molecular interactions. Of key importance is the evolution of binding specificity, the set of interactions made by a protein, since change in specificity can lead to “rewiring” of interaction networks. Unfortunately, the interfaces through which proteins interact are complex, typically containing many amino-acid residues that collectively must contribute to binding specificity as well as binding affinity, structural integrity of the interface and solubility in the unbound state. Results: In order to study the relationship between interface composition and binding specificity, we make use of paralogous pairs of yeast proteins. Immediately after duplication these paralogues will have identical sequences and protein products that make an identical set of interactions. As the sequences diverge, we can correlate amino-acid change in the interface with any change in the specificity of binding. We show that change in interface regions correlates only weakly with change in specificity, and many variants in interfaces are functionally equivalent. We show that many of the residue replacements within interfaces are silent with respect to their contribution to binding specificity. Conclusions: We conclude that such functionally-equivalent change has the potential to contribute to evolutionary plasticity in interfaces by creating cryptic variation, which in turn may provide the raw material for functional innovation and coevolution.BBSRCWellcome Trust Institutional Strategic Support Awar