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Malaria-causing Plasmodium sporozoites are deposited in the dermis by the bite of an infected mosquito and move by gliding motility to the liver where they invade and develop within host hepatocytes. Although extracellular interactions between Plasmodium sporozoite ligands and host receptors provide important guidance cues for productive infection and are good vaccine targets, these interactions remain largely uncharacterized. Thrombospondin- related anonymous protein (TRAP) is a parasite cell surface ligand that is essential for both gliding motility and invasion because it couples the extracellular binding of host receptors to the parasite cytoplasmic actinomyosin motor; however, the molecular nature of the host TRAP receptors is poorly defined. Here, we use a systematic extracellular protein interaction screening approach to identify the integrin αvβ3 as a directly interacting host receptor for Plasmodium falciparum TRAP. Biochemical characterization of the interaction suggests a two-site binding model, requiring contributions from both the von Willebrand factor A domain and the RGD motif of TRAP for integrin binding. We show that TRAP binding to cells is promoted in the presence of integrinactivating proadhesive Mn2+ ions, and that cells genetically targeted so that they lack cell surface expression of the integrin αvsubunit are no longer able to bind TRAP. P. falciparum sporozoites moved with greater speed in the dermis of Itgb3-deficient mice, suggesting that the interaction has a role in sporozoite migration. The identification of the integrin αvβ3 as the host receptor for TRAP provides an important demonstration of a sporozoite surface ligand that directly interacts with host receptors. [ABSTRACT FROM AUTHOR]

The possibility of linking paper to digital information is enhanced by recent developments in printed electronics. In this article we report the design and evaluation of a local newspaper augmented with capacitive touch regions and an embedded Bluetooth chip working with an adjunct device. These allowed the interactive playback of associated audio and the registration of manual voting actions on the web. Design conventions inherited from paper and the web were explored by showing four different versions of an interactive newspaper to 16 community residents. The diverse responses of residents are described, outlining the potential of the approach for local journalism and recommendations for the design of interactive newsprint. [ABSTRACT FROM AUTHOR]

The low-temperature properties of glass are distinct from those of crystals due to the presence of poorly understood low-energy excitations. The tunneling model proposes that these are atoms tunneling between nearby equilibria, forming tunneling two-level systems (TLSs). This model is rather successful, but it does not explain the remarkably universal value of the mechanical dissipation $$Q^{-1}$$ near 1 K. The only known exceptions to this universality are the $$Q^{-1}$$ of certain thin films of amorphous silicon, carbon and germanium. Recently, it was found that $$Q^{-1}$$ of amorphous silicon (a-Si) films can be reduced by two orders of magnitude by increasing the temperature of the substrate during deposition. According to the tunneling model, the reduction in $$Q^{-1}$$ at 1 K implies a reduction in $$P_{0}\gamma ^{2}$$ , where $$P_{0}$$ is the density of TLSs and $$\gamma $$ is their coupling to phonons. In this preliminary report, we demonstrate elastic measurements of a-Si films down to 20 mK. This will allow us, in future work, to determine whether $$P_{0}$$ or $$\gamma $$ is responsible for the reduction in $$Q^{-1}$$ with deposition temperature. [ABSTRACT FROM AUTHOR]

Summary The genomes of malaria parasites contain many genes of unknown function. To assist drug development through the identification of essential genes and pathways, we have measured competitive growth rates in mice of 2,578 barcoded Plasmodium berghei knockout mutants, representing >50% of the genome, and created a phenotype database. At a single stage of its complex life cycle, P. berghei requires two-thirds of genes for optimal growth, the highest proportion reported from any organism and a probable consequence of functional optimization necessitated by genomic reductions during the evolution of parasitism. In contrast, extreme functional redundancy has evolved among expanded gene families operating at the parasite-host interface. The level of genetic redundancy in a single-celled organism may thus reflect the degree of environmental variation it experiences. In the case of Plasmodium parasites, this helps rationalize both the relative successes of drugs and the greater difficulty of making an effective vaccine. [ABSTRACT FROM AUTHOR]

Malaria transmission to mosquitoes requires a developmental switch in asexually dividing blood-stage parasites to sexual reproduction. In Plasmodium berghei, the transcription factor AP2-G is required and sufficient for this switch, but how a particular sex is determined in a haploid parasite remains unknown. Using a global screen of barcoded mutants, we here identify genes essential for the formation of either male or female sexual forms and validate their importance for transmission. High-resolution single-cell transcriptomics of ten mutant parasites portrays the developmental bifurcation and reveals a regulatory cascade of putative gene functions in the determination and subsequent differentiation of each sex. A male-determining gene with a LOTUS/OST-HTH domain as well as the protein interactors of a female-determining zinc-finger protein indicate that germ-granule-like ribonucleoprotein complexes complement transcriptional processes in the regulation of both male and female development of a malaria parasite., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Influenza is a common respiratory infection associated with a substantial clinical, humanistic, and economic burden globally. Vaccines are essential to prevent and control influenza and are recommended by public-health agencies, such as the WHO and US CDC; however, vaccination rates vary considerably across the globe. This review aimed to investigate the perceived barriers and attitudes to influenza vaccination in the global population, in order to identify strategies that may improve influenza vaccination coverage. A structured literature search was undertaken to identify studies that reported on patient-reported attitudes towards influenza vaccination, focused on the adult general population in 16 prespecified countries. Eighty studies were included in this review. Negative attitude towards healthcare were found to be the most agreed upon barrier to vaccine uptake (31.1% agreement). The most agreed promoter of influenza vaccination was trust in healthcare services (62.0% agreement). Approximately 50% of participants intended to receive the influenza vaccine in the following season. To improve influenza vaccination coverage, healthcare workers must strengthen the foundation of substantial trust in healthcare services and provide educational materials that improve influenza vaccination knowledge among the adult general population.

The crossing of the mosquito midgut epithelium by the malaria parasite motile ookinete form represents the most extreme population bottleneck in the parasite life cycle and is a prime target for transmission blocking strategies. However, we have little understanding of the clonal variation that exists in a population of ookinetes in the vector, partially because the parasites are difficult to access and are found in low numbers. Within a vector, variation may result as a response to specific environmental cues or may exist independent of those cues as a potential bet-hedging strategy. Here we use single-cell RNA-seq to profile transcriptional variation in Plasmodium berghei ookinetes across different vector species, and between and within individual midguts. We then compare our results to low-input transcriptomes from individual Anopheles coluzzii midguts infected with the human malaria parasite Plasmodium falciparum . Although the vast majority of transcriptional changes in ookinetes are driven by development, we have identified candidate genes that may be responding to environmental cues or are clonally variant within a population. Our results illustrate the value of single-cell and low-input technologies in understanding clonal variation of parasite populations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Witmer, Dahalan, Metcalf, Talman, Howick and Lawniczak.)

Sporozoites are a motile form of malaria-causing Plasmodium falciparum parasites that migrate from the site of transmission in the dermis through the bloodstream to invade hepatocytes. Sporozoites interact with many cells within the host, but the molecular identity of these interactions and their role in the pathology of malaria is poorly understood. Parasite proteins that are secreted and embedded within membranes are known to be important for these interactions, but our understanding of how they interact with each other to form functional complexes is largely unknown. Here, we compile a library of recombinant proteins representing the repertoire of cell surface and secreted proteins from the P. falciparum sporozoite and use an assay designed to detect extracellular interactions to systematically identify complexes. We identify three protein complexes including an interaction between two components of the p24 complex that is involved in the trafficking of glycosylphosphatidylinositol-anchored proteins through the secretory pathway. Plasmodium parasites lacking either gene are strongly inhibited in the establishment of liver-stage infections. These findings reveal an important role for the p24 complex in malaria pathogenesis and show that the library of recombinant proteins represents a valuable resource to investigate P. falciparum sporozoite biology., Competing Interests: Conflict of interest The authors declare no competing interests., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Intracellular pathogens mobilize host signaling pathways of their host cell to promote their own survival. Evidence is emerging that signal transduction elements are activated in a-nucleated erythrocytes in response to infection with malaria parasites, but the extent of this phenomenon remains unknown. Here, we fill this knowledge gap through a comprehensive and dynamic assessment of host erythrocyte signaling during infection with Plasmodium falciparum. We used arrays of 878 antibodies directed against human signaling proteins to interrogate the activation status of host erythrocyte phospho-signaling pathways at three blood stages of parasite asexual development. This analysis reveals a dynamic modulation of many host signalling proteins across parasite development. Here we focus on the hepatocyte growth factor receptor (c-MET) and the MAP kinase pathway component B-Raf, providing a proof of concept that human signaling kinases identified as activated by malaria infection represent attractive targets for antimalarial intervention.

Plasmodium gene functions in mosquito and liver stages remain poorly characterized due to limitations in the throughput of phenotyping at these stages. To fill this gap, we followed more than 1,300 barcoded P. berghei mutants through the life cycle. We discover 461 genes required for efficient parasite transmission to mosquitoes through the liver stage and back into the bloodstream of mice. We analyze the screen in the context of genomic, transcriptomic, and metabolomic data by building a thermodynamic model of P. berghei liver-stage metabolism, which shows a major reprogramming of parasite metabolism to achieve rapid growth in the liver. We identify seven metabolic subsystems that become essential at the liver stages compared with asexual blood stages: type II fatty acid synthesis and elongation (FAE), tricarboxylic acid, amino sugar, heme, lipoate, and shikimate metabolism. Selected predictions from the model are individually validated in single mutants to provide future targets for drug development., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Malaria is caused by parasites of the genus Plasmodium. All human-infecting Plasmodium species can establish long-lasting chronic infections 1-5 , creating an infectious reservoir to sustain transmission 1,6 . It is widely accepted that the maintenance of chronic infection involves evasion of adaptive immunity by antigenic variation 7 . However, genes involved in this process have been identified in only two of five human-infecting species: Plasmodium falciparum and Plasmodium knowlesi. Furthermore, little is understood about the early events in the establishment of chronic infection in these species. Using a rodent model we demonstrate that from the infecting population, only a minority of parasites, expressing one of several clusters of virulence-associated pir genes, establishes a chronic infection. This process occurs in different species of parasites and in different hosts. Establishment of chronicity is independent of adaptive immunity and therefore different from the mechanism proposed for maintenance of chronic P. falciparum infections 7-9 . Furthermore, we show that the proportions of parasites expressing different types of pir genes regulate the time taken to establish a chronic infection. Because pir genes are common to most, if not all, species of Plasmodium 10 , this process may be a common way of regulating the establishment of chronic infections.