Piperazine sulfonamide BACE1 inhibitors: Design,synthesis, and in vivo characterization

With collaboration between chemistry, X-ray crystallography, and molecular modeling, we designed and synthesized a series of novel piperazine sulfonamide BACE1 inhibitors. Iterative exploration of the non-prime side and S2′ sub-pocket of the enzyme culminated in identification of an analog that potently lowers peripheral Aβ₄₀ in transgenic mice with a single subcutaneous dose.     

Automated Bayesian model development for frequency detection in biological time series

Background

The ability to perform quantitative studies using isotope tracers and metabolic flux analysis (MFA) is critical for detecting pathway bottlenecks and elucidating network regulation in biological systems, especially those that have been engineered to alter their native metabolic capacities. Mathematically, MFA models are traditionally formulated using separate state variables for reaction fluxes and isotopomer abundances. Analysis of isotope labeling experiments using this set of variables results in a non-convex optimization problem that suffers from both implementation complexity and convergence problems.

Results

This article addresses the mathematical and computational formulation of ¹³C MFA models using a new set of variables referred to as fluxomers. These composite variables combine both fluxes and isotopomer abundances, which results in a simply-posed formulation and an improved error model that is insensitive to isotopomer measurement normalization. A powerful fluxomer iterative algorithm (FIA) is developed and applied to solve the MFA optimization problem. For moderate-sized networks, the algorithm is shown to outperform the commonly used 13CFLUX cumomer-based algorithm and the more recently introduced OpenFLUX software that relies upon an elementary metabolite unit (EMU) network decomposition, both in terms of convergence time and output variability.

Conclusions

Substantial improvements in convergence time and statistical quality of results can be achieved by applying fluxomer variables and the FIA algorithm to compute best-fit solutions to MFA models. We expect that the fluxomer formulation will provide a more suitable basis for future algorithms that analyze very large scale networks and design optimal isotope labeling experiments.     

Identification and characterization of 17 microsatellite primers for the tick,Ixodes ricinus,using enriched genomic libraries

Ixodes ricinus is the main vector for important infectious diseases in both humans and in animals. Microsatellite loci were isolated from a dinucleotide‐enriched library made from I. ricinus sampled in Norway. Seventeen polymorphic microsatellites were further characterized among 24 individuals sampled from an island in the Oslofjord region. The number of observed alleles ranged from two to 17 and the observed heterozygosities between 0.10 and 0.83. Analysis of family materials gives evidence of non‐Mendelian inheritance of several of the characterized loci, among which most could be explained by presence of null alleles.     

First Record of Teratopactus nodicollis (Coleoptera: Curculionidae) in Dry Bean (Phaseolus vulgaris)

Observations on the bioecology and damage of Teratopactus nodicollis Boheman on Phaseolus vulgaris were carried out on field samples by assessing the number of larvae and root damage in 40?ha of a dry bean field from the Federal District, Brazil (16°4??28.41???W; 47°30??21.13???S). Larvae caused the greatest damage at the stage of germination, emergence, and primary leaves, producing 50?% stand reduction. Most larvae pupated in August and September, and adult emergence occurred in middle October. Some larvae were infected with the fungus Metarhizium spp., a biological agent that would be naturally controlling this insect.     

Genetic Characterisation of Malawian Pneumococci Prior to the Roll-Out of the PCV13 Vaccine Using a High-Throughput Whole Genome Sequencing Approach

Background

Malawi commenced the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) into the routine infant immunisation schedule in November 2011. Here we have tested the utility of high throughput whole genome sequencing to provide a high-resolution view of pre-vaccine pneumococcal epidemiology and population evolutionary trends to predict potential future change in population structure post introduction.

Methods

One hundred and twenty seven (127) archived pneumococcal isolates from randomly selected adults and children presenting to the Queen Elizabeth Central Hospital, Blantyre, Malawi underwent whole genome sequencing.

Results

The pneumococcal population was dominated by serotype 1 (20.5% of invasive isolates) prior to vaccine introduction. PCV13 is likely to protect against 62.9% of all circulating invasive pneumococci (78.3% in under-5-year-olds). Several Pneumococcal Molecular Epidemiology Network (PMEN) clones are now in circulation in Malawi which were previously undetected but the pandemic multidrug resistant PMEN1 lineage was not identified. Genome analysis identified a number of novel sequence types and serotype switching.

Conclusions

High throughput genome sequencing is now feasible and has the capacity to simultaneously elucidate serotype, sequence type and as well as detailed genetic information. It enables population level characterization, providing a detailed picture of population structure and genome evolution relevant to disease control. Post-vaccine introduction surveillance supported by genome sequencing is essential to providing a comprehensive picture of the impact of PCV13 on pneumococcal population structure and informing future public health interventions.     

Novel racemosin B derivatives as new therapeutic agents for aggressive breast cancer

Carbazole derivatives show anti-cancer activity and are of great interest for drug development. In this study, we synthesized and analyzed several new alkylamide derivatives of racemocin B, a natural indolo[3,2-a]carbazole molecule originally isolated from the green alga Caulerpa racemose. Several alkylamide derivatives were found to exhibit moderate to strong growth inhibition against human breast cancer cell lines. They induced G2/M cell cycle arrest and apoptosis in the aggressive triple-negative breast cancer cell line MDA-MB-231. Among these derivatives, compound 25 with the lowest IC₅₀ induced cell death by suppressing autophagy. This was accompanied by inhibition of autophagic flux and accumulation of autophagy protein 1 light chain 3, LC3II, and p62. The novel alkylamide derivative offers a potential new treatment for human breast cancer.     

Optimising informed consent for participants in a randomised controlled trial in rural Uganda: a comparative prospective cohort mixed-methods study

Background

Poor participant understanding of research information can be a problem in community interventional studies with rural African women, whose levels of illiteracy are high. This study aimed to improve the informed consent process for women living in rural eastern Uganda. We assessed the impact of alternative consent models on participants’ understanding of clinical trial information and their contribution to the informed consent process in rural Uganda.

Methods

The study applied a parallel mixed-methods design for a prospective comparative cohort, nested within a pilot study on the community distribution of an alcohol-based hand rub to prevent neonatal sepsis (BabyGel pilot trial). Women of at least 34 weeks’ pregnancy, suitable for inclusion in the BabyGel pilot trial, were recruited into this study from their homes in 13 villages in Mbale District. As part of the informed consent process, information about the trial was presented using one of three consent methods: standard researcher-read information, a slide show using illustrated text on a flip chart or a video showing the patient information being read as if by a newsreader in either English or the local language. In addition, all women received the patient information sheet in their preferred language. Each information-giving method was used in recruitment for 1 week. Two days after recruitment, women’s understanding of the clinical trial was evaluated using the modified Quality of Informed Consent (QuIC) tool. They were also shown the other two methods and their preference assessed using a 5-point Likert scale. Semi-structured interviews were administered to each participant. The interviews were audio-recorded, transcribed and translated verbatim, and thematically analysed.

Results

A total of 30 pregnant women in their homes participated in this study. Their recall of the trial information within the planned 48 h was assessed for the majority (90%, 27/30). For all three consent models, women demonstrated a high understanding of the study. There was no statistically significant difference between the slide-show message (mean 4.7; standard deviation, SD 0.47; range 4–5), video message (mean 4.9; SD 0.33; range 4–5) and standard method (mean 4.5; SD 0.53; range 4–5; all one-way ANOVA, p =?0.190). The slide-show message resulted in the most objective understanding of question items with the highest average QuIC score of 100 points. For women who had been recruited using any of the three models, the slide show was the most popular method, with a mean score for all items of not less than 4.2 (mean 4.8; SD 0.6; range 4–5). Most women (63%, 19/30) preferred the slide-show message, compared with 17% (5/30) and 20% (6/30) for the standard and video messages, respectively. The reasons given included the benefits of having pictures to aid understanding and the logical progression of the information.

Conclusion

Our results from this small study suggest that slide-show messages may be an effective and popular alternative way of presenting trial information to women in rural Uganda, many of whom have little or no literacy.

Trial registration

ISRCTN, ISRCTN67852437. Registered on 18 March 2018.

     

The telocentric complement of Tradescantia micrantha

Stable telocentrics are present in a number of plant species but rarely form a major part of a complement and almost never constitute its whole. T. micrantha (2n=24) is an exceptional, possibly unique, plant in which all the chromosomes are of this type. They fall into three size categories (L, M, and S) each forming quadrivalents with frequencies positively correlated with chromosome length: it is concluded that the species is autotetraploid. Pairing and segregational errors result in high frequencies of gametic aneuploidy — a fact which is taken to reflect the vegetative vigour of the species and a low level of selection for sexual fertility. The cytological features determined in this study provide a basis for discussing the significance and mode of evolution of the complement.     

The Diagnostic and Prognostic Accuracy of Five Markers of Serious Bacterial Infection in Malawian Children with Signs of Severe Infection

Background

Early recognition and prompt and appropriate antibiotic treatment can significantly reduce mortality from serious bacterial infections (SBI). The aim of this study was to evaluate the utility of five markers of infection: C-reactive protein (CRP), procalcitonin (PCT), soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), CD163 and high mobility group box-1 (HMGB1), as markers of SBI in severely ill Malawian children.

Methodology and Principal Findings

Children presenting with a signs of meningitis (n = 282) or pneumonia (n = 95), were prospectively recruited. Plasma samples were taken on admission for CRP, PCT, sTREM-1 CD163 and HMGB1 and the performance characteristics of each test to diagnose SBI and to predict mortality were determined. Of 377 children, 279 (74%) had SBI and 83 (22%) died. Plasma CRP, PCT, CD163 and HMGB1 and were higher in HIV-infected children than in HIV-uninfected children (p<0.01). In HIV-infected children, CRP and PCT were higher in children with SBI compared to those with no detectable bacterial infection (p<0.0005), and PCT and CD163 were higher in non-survivors (p = 0.001, p = 0.05 respectively). In HIV-uninfected children, CRP and PCT were also higher in children with SBI compared to those with no detectable bacterial infection (p<0.0005), and CD163 was higher in non-survivors (p = 0.05). The best predictors of SBI were CRP and PCT, and areas under the curve (AUCs) were 0.81 (95% CI 0.73–0.89) and 0.86 (95% CI 0.79–0.92) respectively. The best marker for predicting death was PCT, AUC 0.61 (95% CI 0.50–0.71).

Conclusions

Admission PCT and CRP are useful markers of invasive bacterial infection in severely ill African children. The study of these markers using rapid tests in a less selected cohort would be important in this setting.