Describing the current status of Plasmodium falciparum population structure and drug resistance within mainland Tanzania using molecular inversion probes

High‐throughput Plasmodium genomic data is increasingly useful in assessing prevalence of clinically important mutations and malaria transmission patterns. Understanding parasite diversity is important for identification of specific human or parasite populations that can be targeted by control programmes, and to monitor the spread of mutations associated with drug resistance. An up‐to‐date understanding of regional parasite population dynamics is also critical to monitor the impact of control efforts. However, this data is largely absent from high‐burden nations in Africa, and to date, no such analysis has been conducted for malaria parasites in Tanzania countrywide. To this end, over 1,000 P. falciparum clinical isolates were collected in 2017 from 13 sites in seven administrative regions across Tanzania, and parasites were genotyped at 1,800 variable positions genome‐wide using molecular inversion probes. Population structure was detectable among Tanzanian P. falciparum parasites, approximately separating parasites from the northern and southern districts and identifying genetically admixed populations in the north. Isolates from nearby districts were more likely to be genetically related compared to parasites sampled from more distant districts. Known drug resistance mutations were seen at increased frequency in northern districts (including two infections carrying pfk13‐R561H), and additional variants with undetermined significance for antimalarial resistance also varied by geography. Malaria Indicator Survey (2017) data corresponded with genetic findings, including average region‐level complexity‐of‐infection and malaria prevalence estimates. The parasite populations identified here provide important information on extant spatial patterns of genetic diversity of Tanzanian parasites, to which future surveys of genetic relatedness can be compared.     

The Solanum pimpinellifolium Cf-ECP1 and Cf-ECP4 genes for resistance to Cladosporium fulvum are located at the Milky Way locus on the short arm of chromosome 1

The interaction between tomato and the leaf mould pathogen Cladosporium fulvum is an excellent model to study gene-for-gene interactions and plant disease resistance gene evolution. Most Cf genes were introgressed into cultivated tomato (Solanum lycopersicum) from wild relatives such as S. pimpinellifolium and novel Cf-ECP genes were recently identified in this species. Our objective is to isolate Cf-ECP1, Cf-ECP2, Cf-ECP4 and Cf-ECP5 to increase our understanding of Cf gene evolution, and the molecular basis for recognition specificity in Cf proteins. The map locations of Cf-ECP2 and Cf-ECP5 have been reported previously and we report here that Cf-ECP1 and Cf-ECP4 map to a different locus on the short arm of chromosome 1. The analysis of selected recombinants and allelism tests showed both genes are located at Milky Way together with Cf-9 and Cf-4. Our results emphasise the importance of this locus in generating novel Cf genes for resistance to C. fulvum. Candidate genes for Cf-ECP1 and Cf-ECP4 were also identified by DNA gel blot analysis of bulked segregant pools. In addition, we generated functional cassettes for expression of the C. fulvum ECP1, ECP2, ECP4 and ECP5 proteins using recombinant Potato Virus X, and three ECPs were also expressed in stable transformed plants. Using marker-assisted selection we have also identified recombinants containing Cf-ECP1, Cf-ECP2, Cf-ECP4 or Cf-ECP5 in cis with a linked T-DNA carrying the non-autonomous Zea mays transposon Dissociation. Using these resources it should now be possible to isolate all four Cf-ECPs using transposon tagging, or a candidate gene strategy. Eleni Soumpourou and Michael Iakovidis contributed equally to this work.     

Colony size, cell number, carbon and nitrogen contents of Phaeocystis pouchetii from western Norway

Phaeocystis pouchetii is an ecologically important colony-formingmarine phytoplankton species in northern hemisphere cold waters.It plays a central role in the processing of biogeochemicallyimportant elements in the upper ocean during spring blooms.Here, we report highly significant quantitative relationshipsamong colony size, cell number and particulate carbon and nitrogencontents of field populations of P. pouchetii, which providethe means to quantitatively convert its biological expressioninto units of biogeochemical significance. Populations weresampled from mesocosms incubated in situ in western Norway andeither fertilized with nitrate and phosphate or left unamended.Phaeocystis colony blooms developed in both scenarios, but weremuch greater in fertilized treatments. Colonies from the lattertreatments were larger, contained higher concentrations of cellsand more particulate carbon and nitrogen than those in the unfertilizedmesocosm. Considering all data, log cell number increased linearlywith log colony volume with a slope of 0.54. Log carbon andnitrogen increased with log colony volume, with respective slopesof 0.92 and 1.22, indicating a significant component of non-cellularcarbon and nitrogen within the colonies. Carbon and nitrogencontents of colonies were linearly related, and fertilized coloniescontained more nitrogen relative to carbon than unfertilizedcolonies. These equations are particularly applicable to contemporarystudies of P. pouchetii because they represent colonies growingin environments that mimic a continuum from natural to eutrophicatedecosystems.     

Novel nucleotide triphosphates as potent P2Y2 agonists with enhanced stability over UTP

The synthesis of a series of novel C-linked nucleotide triphosphates is reported. These exhibit excellent agonist potency and selectivity for the P2Y2 receptor with a number of examples having EC50 values below 10 nM. Representative compounds from the N-linked and C-linked series showed enhanced metabolic stability compared with that of the natural ligand UTP.     

Patients’ preferences for osteoporosis drug treatment: a discrete-choice experiment

Introduction

The patient’s perspective is becoming increasingly important in clinical and policy decisions. In this study, we aimed to evaluate the preferences of patients with, or at risk of, osteoporosis for medication attributes, and to establish how patients trade between these attributes.

Methods

A discrete choice experiment survey was designed and patients were asked to choose between two hypothetical unlabelled drug treatments (and an opt-out option) that vary in five attributes: efficacy in reducing the risk of fracture, type of potential common side-effects, mode and frequency of administration and out-of-pocket costs. An efficient experimental design was used to construct the treatment option choice sets and a mixed logit panel data model was used to estimate patients’ preferences and trade-offs between attributes.

Results

A total of 257 patients with, or at risk of, osteoporosis completed the experiment. As expected, patients preferred treatment with higher effectiveness and lower cost. They also preferred either an oral monthly tablet or 6-month subcutaneous injection above weekly oral tablets, 3-month subcutaneous, 3-month intravenous or yearly intravenous injections. Patients disliked being at risk of gastro-intestinal disorders more than being at risk of skin reactions and flu-like symptoms. There was significant variation in preferences across the sample for all attributes except subcutaneous injection.

Conclusions

This study revealed that osteoporotic patients preferred 6-month subcutaneous injection and oral monthly tablet, and disliked gastro-intestinal disorders. Moreover, patients were willing to pay a personal contribution or to trade treatment efficacy for better levels of other attributes. Preferences for treatment attributes varied across patients and this highlights the importance of clinical decision-making taking individual preferences into account to improve osteoporosis care.     

Synthesis and profile of SCH351591, a novel PDE4 inhibitor

The syntheses and pharmacological profiles of some 2-trifluoromethyl-8-methoxyquinoline-5-carboxamides are described. SCH351591 is a potent selective inhibitor of phosphodiesterase type 4 (PDE4).     

IRAK-4 inhibitors. Part III: a series of imidazo[1,2-a]pyridines

Following the identification of a potent IRAK inhibitor through routine project cross screening, a novel class of IRAK-4 inhibitor was established. The SAR of imidazo[1,2-a]pyridino-pyridines and benzimidazolo-pyridines was explored.     

Nonlinear CO2 flux response to 7 years of experimentally induced permafrost thaw

Rapid Arctic warming is expected to increase global greenhouse gas concentrations as permafrost thaw exposes immense stores of frozen carbon (C) to microbial decomposition. Permafrost thaw also stimulates plant growth, which could offset C loss. Using data from 7 years of experimental Air and Soil warming in moist acidic tundra, we show that Soil warming had a much stronger effect on CO₂ flux than Air warming. Soil warming caused rapid permafrost thaw and increased ecosystem respiration (R_eco), gross primary productivity (GPP), and net summer CO₂ storage (NEE). Over 7 years R_eco, GPP, and NEE also increased in Control (i.e., ambient plots), but this change could be explained by slow thaw in Control areas. In the initial stages of thaw, R_eco, GPP, and NEE increased linearly with thaw across all treatments, despite different rates of thaw. As thaw in Soil warming continued to increase linearly, ground surface subsidence created saturated microsites and suppressed R_eco, GPP, and NEE. However R_eco and GPP remained high in areas with large Eriophorum vaginatum biomass. In general NEE increased with thaw, but was more strongly correlated with plant biomass than thaw, indicating that higher R_eco in deeply thawed areas during summer months was balanced by GPP. Summer CO₂ flux across treatments fit a single quadratic relationship that captured the functional response of CO₂ flux to thaw, water table depth, and plant biomass. These results demonstrate the importance of indirect thaw effects on CO₂ flux: plant growth and water table dynamics. Nonsummer R_eco models estimated that the area was an annual CO₂ source during all years of observation. Nonsummer CO₂ loss in warmer, more deeply thawed soils exceeded the increases in summer GPP, and thawed tundra was a net annual CO₂ source.