ABSTRACT
We describe a next-generation Drosophila protein interaction map-"DPIM2"-established from affinity purification-mass spectrometry of 5,805 baits, covering the largest fraction of the Drosophila proteome. The network contains 32,668 interactions among 3,644 proteins, organized into 632 clusters representing putative functional modules. Our analysis expands the pool of known protein interactions in Drosophila, provides annotation for poorly studied genes, and postulates previously undescribed protein interaction relationships. The predictive power and functional relevance of this network are probed through the lens of the Notch signaling pathway, and we find that newly identified members of complexes that include known Notch modifiers can also modulate Notch signaling. DPIM2 allows direct comparisons with a recently published human protein interaction network, defining the existence of functional interactions conserved across species. Thus, DPIM2 defines a valuable resource for predicting protein co-complex memberships and functional associations as well as generates functional hypotheses regarding specific protein interactions.
ABSTRACT
Patient-led advocacy organizations in the anaplastic lymphoma kinase (ALK)-positive lung cancer space are becoming increasingly influential. ALK Positive Inc. (hereafter "ALK Positive") is probably the most widely known among these organizations. Evolving from a private Facebook Support Group created in 2015 to provide a forum for ALK-positive lung cancer patients and caregivers to exchange information, empathy and support, ALK Positive transitioned in 2021 into a 501(c)(3) non-profit organization (NPO), with the mission to improve the life expectancy and quality of life for ALK-positive cancer patients worldwide. This review provides a historical perspective on the growth, activities and aspirations of ALK Positive to pursue patient advocacy and enable development of new therapies for individuals with ALK-positive cancers. This growth has been enabled by the collaborative efforts of ALK-positive cancer patients, their care-partners and oncologists, academic researchers, other NPO advocacy organizations, and members of the biotech and pharma communities who develop new therapies for ALK-positive cancers. ALK Positive has grown to provide a variety of patient services, to award competitive support for translational research and clinical trials intended to enable new therapies and improved quality and extent of life for ALK-positive cancer patients, and to collaborate with industry and academia to accelerate the development of improved therapies for ALK-positive cancer patients. ALK Positive continues grappling with a variety of challenges including further improving patient quality of life, enabling the development of new therapies, and extending its already substantial global reach and impact. This review summarizes many of the tangible impacts and aspirations engendered by ALK Positive for ALK-positive cancer patients in the past, present and future tenses-where we have been, where we stand and where we hope to go. The content is based on the historical recollections of the authors, and is accurate as of November 30, 2022, to the best of the authors' knowledge.
ABSTRACT
Myelinating oligodendrocytes are essential for central nervous system (CNS) formation and function. Their disruption is implicated in numerous neurodevelopmental, neuropsychiatric and neurodegenerative disorders. However, recent studies have indicated that oligodendrocytes may be tractable for treatment of disease. In recent years, zebrafish have become well established for the study of myelinating oligodendrocyte biology and drug discovery in vivo. Here, by automating the delivery of zebrafish larvae to a spinning disk confocal microscope, we were able to automate high-resolution imaging of myelinating oligodendrocytes in vivo. From there, we developed an image analysis pipeline that facilitated a screen of compounds with epigenetic and post-translational targets for their effects on regulating myelinating oligodendrocyte number. This screen identified novel compounds that strongly promote myelinating oligodendrocyte formation in vivo. Our imaging platform and analysis pipeline is flexible and can be employed for high-resolution imaging-based screens of broad interest using zebrafish.
Subject(s)
Genetic Testing , Myelin Sheath/metabolism , Zebrafish/genetics , Animals , Animals, Genetically Modified , Automation , Cell Count , Fluorescence , High-Throughput Screening Assays , Image Processing, Computer-Assisted , Larva/metabolism , Naphthalenes/pharmacology , Oligodendroglia/cytology , Pyrones/pharmacology , Reproducibility of Results , Spinal Cord/metabolism , Time-Lapse ImagingABSTRACT
BACKGROUND: Insect metamorphosis relies on temporal and spatial cues that are precisely controlled. Previous studies in Drosophila have shown that untimely activation of genes that are essential to metamorphosis results in growth defects, developmental delay and death. Multiple factors exist that safeguard these genes against dysregulated expression. The list of identified negative regulators that play such a role in Drosophila development continues to expand. RESULTS: By using RNAi transgene-induced gene silencing coupled to spatio/temporal assessment, we have unraveled an important role for the Drosophila dopamine 1-like receptor, Dop1R2, in development. We show that Dop1R2 knockdown leads to pre-adult lethality. In adults that escape death, abnormal wing expansion and/or melanization defects occur. Furthermore we show that salivary gland expression of this GPCR during the late larval/prepupal stage is essential for the flies to survive through adulthood. In addition to RNAi-induced effects, treatment of larvae with the high affinity D1-like receptor antagonist flupenthixol, also results in developmental arrest, and in morphological defects comparable to those seen in Dop1R2 RNAi flies. To examine the basis for pupal lethality in Dop1R2 RNAi flies, we carried out transcriptome analysis. These studies revealed up-regulation of genes that respond to ecdysone, regulate morphogenesis and/or modulate defense/immunity. CONCLUSION: Taken together our findings suggest a role for Dop1R2 in the repression of genes that coordinate metamorphosis. Premature release of this inhibition is not tolerated by the developing fly.
Subject(s)
Drosophila Proteins/genetics , Drosophila melanogaster/genetics , Gene Expression Regulation, Developmental , Metamorphosis, Biological/genetics , Receptors, Dopamine D1/genetics , Animals , Animals, Genetically Modified , Drosophila melanogaster/growth & development , Drosophila melanogaster/metabolism , Gene Expression Profiling/methods , Larva/genetics , Larva/growth & development , Pupa/genetics , Pupa/growth & development , RNA Interference , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
RNA interference (RNAi), a naturally occurring phenomenon in eukaryotic organisms, is an extremely valuable tool that can be utilized in the laboratory for functional genomic studies. The ability to knockdown individual genes selectively via this reverse genetic technique has allowed many researchers to rapidly uncover the biological roles of numerous genes within many organisms, by evaluation of loss-of-function phenotypes. In the major human malaria vector Anopheles gambiae, the predominant method used to reduce the function of targeted genes involves injection of double-stranded (dsRNA) into the hemocoel of the adult mosquito. While this method has been successful, gene knockdown in adults excludes the functional assessment of genes that are expressed and potentially play roles during pre-adult stages, as well as genes that are expressed in limited numbers of cells in adult mosquitoes. We describe a method for the injection of Serine Protease Inhibitor 2 (SRPN2) dsRNA during the early pupal stage and validate SRPN2 protein knockdown by observing decreased target protein levels and the formation of melanotic pseudo-tumors in SRPN2 knockdown adult mosquitoes. This evident phenotype has been described previously for adult stage knockdown of SRPN2 function, and we have recapitulated this adult phenotype by SRPN2 knockdown initiated during pupal development. When used in conjunction with a dye-labeled dsRNA solution, this technique enables easy visualization by simple light microscopy of injection quality and distribution of dsRNA in the hemocoel.
Subject(s)
Anopheles/genetics , Gene Transfer Techniques , Pupa/genetics , RNA Interference/physiology , Animals , Female , Genetic Techniques , Malaria , Male , PhenotypeABSTRACT
We understand little about photo-preference and the molecular mechanisms governing vision-dependent behavior in vector mosquitoes. Investigations of the influence of photo-preference on adult mosquito behaviors such as endophagy and exophagy and endophily and exophily will enhance our ability to develop and deploy vector-targeted interventions and monitoring techniques. Our laboratory-based analyses have revealed that crepuscular period photo-preference differs between An. gambiae and An. stephensi. We employed qRT-PCR to assess crepuscular transcriptional expression patterns of long wavelength-, short wavelength-, and ultraviolet wavelength-sensing opsins (i.e., rhodopsin-class G-protein coupled receptors) in An. gambiae and in An. stephensi. Transcript levels do not exhibit consistent differences between species across diurnal cycles, indicating that differences in transcript abundances within this gene set are not correlated with these behavioral differences. Using developmentally staged and gender-specific RNAseq data sets in An. gambiae, we show that long wavelength-sensing opsins are expressed in two different patterns (one set expressed during larval stages, and one set expressed during adult stages), while short wavelength- and ultraviolet wavelength-sensing opsins exhibit increased expression during adult stages. Genomic organization of An. gambiae opsins suggests paralogous gene expansion of long wavelength-sensing opsins in comparison with An. stephensi. We speculate that this difference in gene number may contribute to variation between these species in photo-preference behavior (e.g., visual sensitivity).
Subject(s)
Anopheles/physiology , Insect Proteins/genetics , Opsins/genetics , Animals , Anopheles/genetics , Anopheles/growth & development , Circadian Rhythm , Female , Insect Proteins/metabolism , Larva/physiology , Male , Molecular Sequence Data , Opsins/metabolism , Real-Time Polymerase Chain Reaction , Sequence Analysis, RNA , Species SpecificityABSTRACT
BACKGROUND: Long non-coding RNAs (lncRNAs) have been defined as mRNA-like transcripts longer than 200 nucleotides that lack significant protein-coding potential, and many of them constitute scaffolds for ribonucleoprotein complexes with critical roles in epigenetic regulation. Various lncRNAs have been implicated in the modulation of chromatin structure, transcriptional and post-transcriptional gene regulation, and regulation of genomic stability in mammals, Caenorhabditis elegans, and Drosophila melanogaster. The purpose of this study is to identify the lncRNA landscape in the malaria vector An. gambiae and assess the evolutionary conservation of lncRNAs and their secondary structures across the Anopheles genus. RESULTS: Using deep RNA sequencing of multiple Anopheles gambiae life stages, we have identified 2,949 lncRNAs and more than 300 previously unannotated putative protein-coding genes. The lncRNAs exhibit differential expression profiles across life stages and adult genders. We find that across the genus Anopheles, lncRNAs display much lower sequence conservation than protein-coding genes. Additionally, we find that lncRNA secondary structure is highly conserved within the Gambiae complex, but diverges rapidly across the rest of the genus Anopheles. CONCLUSIONS: This study offers one of the first lncRNA secondary structure analyses in vector insects. Our description of lncRNAs in An. gambiae offers the most comprehensive genome-wide insights to date into lncRNAs in this vector mosquito, and defines a set of potential targets for the development of vector-based interventions that may further curb the human malaria burden in disease-endemic countries.
Subject(s)
Anopheles/genetics , Epigenesis, Genetic , Nucleic Acid Conformation , RNA, Long Noncoding/genetics , Animals , Conserved Sequence , Drosophila melanogaster/genetics , Gene Expression Regulation , Humans , RNA, Messenger/geneticsABSTRACT
Epigenetic control of gene expression has important implications for the regulation of developmental processes, for mediating homeostasis and responses to the external environment, and for transgenerational inheritance of gene expression patterns. Genes that mediate epigenetic control have been well-characterized in Drosophila melanogaster, and we have identified and analyzed an orthologous gene ensemble in Anopheles gambiae that comprises 169 orthologs related to a 215-member epigenetic gene ensemble in D. melanogaster. We find that this ensemble is highly conserved among anopheline mosquitoes, as we identify only seven gene family expansion/contraction events within the ensemble among 12 mosquito species we have studied within the genus Anopheles. Comparative analyses of the epigenetic gene expression across the genera Drosophila and Anopheles reveal distinct tissue-associated expression patterns in the two genera, but similar temporal expression patterns. The A. gambiae complex and D. melanogaster subgroup epigenetic gene ensembles exhibit similar evolutionary rates, as assessed by their respective dN/dS values. These differences in tissue-associated expression patterns, in contrast to similarities in evolutionary rates and temporal expression patterns, may imply that some members of the epigenetic gene ensemble have been redeployed within one or both genera, in comparison to the most recent common ancestor of these two clades. Members of this epigenetic gene ensemble may constitute another set of potential targets for vector control and enable further reductions in the burden of human malaria, by analogy to recent success in development of small molecule antagonists for mammalian epigenetic machinery.
Subject(s)
Anopheles/genetics , Epigenesis, Genetic , Evolution, Molecular , Genes, Insect , Animals , Drosophila melanogaster/genetics , Insect Proteins/classification , Insect Proteins/genetics , Multigene Family , PhylogenyABSTRACT
Malaria control relies heavily on pyrethroid insecticides, to which susceptibility is declining in Anopheles mosquitoes. To combat pyrethroid resistance, application of alternative insecticides is advocated for indoor residual spraying (IRS), and carbamates are increasingly important. Emergence of a very strong carbamate resistance phenotype in Anopheles gambiae from Tiassalé, Côte d'Ivoire, West Africa, is therefore a potentially major operational challenge, particularly because these malaria vectors now exhibit resistance to multiple insecticide classes. We investigated the genetic basis of resistance to the most commonly-applied carbamate, bendiocarb, in An. gambiae from Tiassalé. Geographically-replicated whole genome microarray experiments identified elevated P450 enzyme expression as associated with bendiocarb resistance, most notably genes from the CYP6 subfamily. P450s were further implicated in resistance phenotypes by induction of significantly elevated mortality to bendiocarb by the synergist piperonyl butoxide (PBO), which also enhanced the action of pyrethroids and an organophosphate. CYP6P3 and especially CYP6M2 produced bendiocarb resistance via transgenic expression in Drosophila in addition to pyrethroid resistance for both genes, and DDT resistance for CYP6M2 expression. CYP6M2 can thus cause resistance to three distinct classes of insecticide although the biochemical mechanism for carbamates is unclear because, in contrast to CYP6P3, recombinant CYP6M2 did not metabolise bendiocarb in vitro. Strongly bendiocarb resistant mosquitoes also displayed elevated expression of the acetylcholinesterase ACE-1 gene, arising at least in part from gene duplication, which confers a survival advantage to carriers of additional copies of resistant ACE-1 G119S alleles. Our results are alarming for vector-based malaria control. Extreme carbamate resistance in Tiassalé An. gambiae results from coupling of over-expressed target site allelic variants with heightened CYP6 P450 expression, which also provides resistance across contrasting insecticides. Mosquito populations displaying such a diverse basis of extreme and cross-resistance are likely to be unresponsive to standard insecticide resistance management practices.
Subject(s)
Anopheles/genetics , Cytochrome P-450 Enzyme System/genetics , Insecticide Resistance/genetics , Malaria/transmission , Acetylcholinesterase/genetics , Africa, Western , Animals , Animals, Genetically Modified/genetics , Carbamates/pharmacology , Drosophila/drug effects , Drosophila/genetics , Malaria/genetics , Phenotype , Phenylcarbamates/pharmacology , Pyrethrins/pharmacologyABSTRACT
The development of resistance to insecticides has become a classic exemplar of evolution occurring within human time scales. In this study we demonstrate how resistance to DDT in the major African malaria vector Anopheles gambiae is a result of both target-site resistance mechanisms that have introgressed between incipient species (the M- and S-molecular forms) and allelic variants in a DDT-detoxifying enzyme. Sequencing of the detoxification enzyme, Gste2, from DDT resistant and susceptible strains of An. gambiae, revealed a non-synonymous polymorphism (I114T), proximal to the DDT binding domain, which segregated with strain phenotype. Recombinant protein expression and DDT metabolism analysis revealed that the proteins from the susceptible strain lost activity at higher DDT concentrations, characteristic of substrate inhibition. The effect of I114T on GSTE2 protein structure was explored through X-ray crystallography. The amino acid exchange in the DDT-resistant strain introduced a hydroxyl group nearby the hydrophobic DDT-binding region. The exchange does not result in structural alterations but is predicted to facilitate local dynamics and enzyme activity. Expression of both wild-type and 114T alleles the allele in Drosophila conferred an increase in DDT tolerance. The 114T mutation was significantly associated with DDT resistance in wild caught M-form populations and acts in concert with target-site mutations in the voltage gated sodium channel (Vgsc-1575Y and Vgsc-1014F) to confer extreme levels of DDT resistance in wild caught An. gambiae.
Subject(s)
Anopheles/genetics , Anopheles/metabolism , DDT/pharmacology , Insecticide Resistance/genetics , Insecticides/pharmacology , Africa , Alleles , Amino Acid Substitution , Animals , Anopheles/drug effects , Catalysis , Enzyme Activation , Female , Gene Expression , Genes, Insect , Genetic Variation , Haplotypes , Models, Molecular , Mutation , Phylogeography , Protein Binding , Protein Conformation , Protein Interaction Domains and Motifs , Recombinant ProteinsABSTRACT
Genetic variation in the mosquito Anopheles gambiae profoundly influences its ability to transmit malaria. Mosquito gut bacteria are shown to influence the outcome of infections with Plasmodium parasites and are also thought to exert a strong drive on genetic variation through natural selection; however, a link between antibacterial effects and genetic variation is yet to emerge. Here, we combined SNP genotyping and expression profiling with phenotypic analyses of candidate genes by RNAi-mediated silencing and 454 pyrosequencing to investigate this intricate biological system. We identified 138 An. gambiae genes to be genetically associated with the outcome of Serratia marcescens infection, including the peptidoglycan recognition receptor PGRPLC that triggers activation of the antibacterial IMD/REL2 pathway and the epidermal growth factor receptor EGFR. Silencing of three genes encoding type III fibronectin domain proteins (FN3Ds) increased the Serratia load and altered the gut microbiota composition in favor of Enterobacteriaceae. These data suggest that natural genetic variation in immune-related genes can shape the bacterial population structure of the mosquito gut with high specificity. Importantly, FN3D2 encodes a homolog of the hypervariable pattern recognition receptor Dscam, suggesting that pathogen-specific recognition may involve a broader family of immune factors. Additionally, we showed that silencing the gene encoding the gustatory receptor Gr9 that is also associated with the Serratia infection phenotype drastically increased Serratia levels. The Gr9 antibacterial activity appears to be related to mosquito feeding behavior and to mostly rely on changes of neuropeptide F expression, together suggesting a behavioral immune response following Serratia infection. Our findings reveal that the mosquito response to oral Serratia infection comprises both an epithelial and a behavioral immune component.
Subject(s)
Anopheles/genetics , Intestinal Mucosa/microbiology , Serratia Infections/genetics , Animals , Anopheles/immunology , Insect Vectors/parasitology , Intestinal Mucosa/immunology , Oligonucleotide Array Sequence Analysis , Polymorphism, Single Nucleotide , Serratia Infections/immunology , Serratia marcescens , TranscriptomeABSTRACT
We report the imminent completion of a set of reference genome assemblies for 16 species of Anopheles mosquitoes. In addition to providing a generally useful resource for comparative genomic analyses, these genome sequences will greatly facilitate exploration of the capacity exhibited by some Anopheline mosquito species to serve as vectors for malaria parasites. A community analysis project will commence soon to perform a thorough comparative genomic investigation of these newly sequenced genomes. Completion of this project via the use of short next-generation sequence reads required innovation in both the bioinformatic and laboratory realms, and the resulting knowledge gained could prove useful for genome sequencing projects targeting other unconventional genomes.
Subject(s)
Anopheles/genetics , Biological Evolution , Genome, Insect , Malaria/genetics , Animals , Base Sequence , Computational Biology , Genomics , Humans , Insect Vectors/genetics , Malaria/parasitology , Malaria/transmission , Sequence Analysis, DNAABSTRACT
BACKGROUND: Mosquitoes transmit many important diseases including malaria, dengue and yellow fever. Disease transmission from one vertebrate host to another depends on repeated blood feedings by single mosquitoes. In order for the mosquito to acquire the blood that it needs to complete oogenesis, the insect must locate a suitable host. Olfactory cues (including carbon dioxide) released by the host and detected by the mosquito are the primary signals that vector insects use for host location. Previous studies have suggested that the physiological status - including bacterial, fungal, viral and Plasmodium infections - can modulate aspects of behavior in haematophagous insects. METHODS: Standard electrophysiological techniques were used to record extracellular responses from the receptor neurons located in sensilla found on the maxillary palps of the insects. The recording microelectrode was inserted through the cuticle at the base of an individual sensillum and the extracellular electrical signals obtained from the three neurons within the sensillum were recorded. Stimulations consisted of 2 s pulses of the desired concentrations of CO(2) or dosages of 1-octen-3-ol. RESULTS: Accordingly, we were interested in determining whether Plasmodium infection affects the sensitivity of those peripheral olfactory sensors that are involved in host-seeking in mosquitoes. Our studies indicate that infection of female Anopheles stephensi with Plasmodium berghei does not alter the response characteristics of the neurons innervating the maxillary palp sensilla that respond to the attractants carbon dioxide and 1-octen-3-ol. Although the response characteristics of the peripheral sensory neurons are not affected by infection status, we found that the age of the mosquito alone does affect the threshold of sensitivity of these neurons to carbon dioxide. The proportion of older insects (21-30 d post-emergence) that responds to 150 ppm carbon dioxide is higher than the proportion that responds among younger insects (1-10 d post-emergence). CONCLUSIONS: Anopheles stephensi infected with Plasmodium berghei exhibit sensitivities to stimulation with carbon dioxide and 1-octen-3-ol similar to those of uninfected mosquitoes. However, the age of the infected or uninfected mosquito does affect the threshold of sensitivity of these neurons to carbon dioxide.
Subject(s)
Anopheles/physiology , Anopheles/parasitology , Plasmodium berghei/growth & development , Sensilla/physiology , Animals , Carbon Dioxide/metabolism , Electrophysiological Phenomena , Female , Neurons/physiology , Octanols/metabolism , Pheromones/metabolismABSTRACT
Understanding genetic causes and effects of speciation in sympatric populations of sexually reproducing eukaryotes is challenging, controversial, and of practical importance for controlling rapidly evolving pests and pathogens. The major African malaria vector mosquito Anopheles gambiae sensu stricto (s.s.) is considered to contain two incipient species with strong reproductive isolation, hybrids between the M and S molecular forms being very rare. Following recent observations of higher proportions of hybrid forms at a few sites in West Africa, we conducted new surveys of 12 sites in four contiguous countries (The Gambia, Senegal, Guinea-Bissau, and Republic of Guinea). Identification and genotyping of 3499 A. gambiae s.s. revealed high frequencies of M/S hybrid forms at each site, ranging from 5 to 42%, and a large spectrum of inbreeding coefficient values from 0.11 to 0.76, spanning most of the range expected between the alternative extremes of panmixia and assortative mating. Year-round sampling over 2 years at one of the sites in The Gambia showed that M/S hybrid forms had similar relative frequencies throughout periods of marked seasonal variation in mosquito breeding and abundance. Genome-wide scans with an Affymetrix high-density single-nucleotide polymorphism (SNP) microarray enabled replicate comparisons of pools of different molecular forms, in three separate populations. These showed strong differentiation between M and S forms only in the pericentromeric region of the X chromosome that contains the molecular form-specific marker locus, with only a few other loci showing minor differences. In the X chromosome, the M/S hybrid forms were more differentiated from M than from S forms, supporting a hypothesis of asymmetric introgression and backcrossing.
Subject(s)
Anopheles/genetics , Genetic Speciation , Africa, Western , Animals , Breeding , Chimera , Chromosomes, Insect/genetics , Gene Frequency , Genome, Insect , Genotype , Phylogeography , Polymorphism, Single Nucleotide , Population/genetics , Seasons , X Chromosome/geneticsABSTRACT
Anopheles gambiae M and S are thought to be undergoing ecological speciation by adapting to different larval habitats. Toward an improved understanding of the genetic determinants and evolutionary processes shaping their divergence, we used a 400,000 single-nucleotide polymorphism (SNP) genotyping array to characterize patterns of genomic differentiation between four geographically paired M and S population samples from West and Central Africa. In keeping with recent studies based on more limited genomic or geographic sampling, divergence was not confined to a few isolated "speciation islands." Divergence was both widespread across the genome and heterogeneous. Moreover, we find consistent patterns of genomic divergence across sampling sites and mutually exclusive clustering of M and S populations using genetic distances based on all 400,000 SNPs, implying that M and S are evolving collectively across the study area. Nevertheless, the clustering of local M and S populations using genetic distances based on SNPs from genomic regions of low differentiation is consistent with recent gene flow and introgression. To account for these data and reconcile apparent paradoxes in reported patterns of M-S genomic divergence and hybridization, we propose that extrinsic ecologically based postmating barriers vary in strength as environmental conditions fluctuate or change.
Subject(s)
Anopheles/genetics , Ecosystem , Evolution, Molecular , Genome, Insect , Africa, Central , Africa, Western , Animals , Anopheles/classification , Environment , Gene Flow , Oligonucleotide Array Sequence Analysis , Polymorphism, Single Nucleotide , Population/genetics , Sequence Analysis, DNAABSTRACT
With the paradigm shift from the reduction of morbidity and mortality to the interruption of transmission, the focus of malaria control broadens from symptomatic infections in children ≤5 years of age to include asymptomatic infections in older children and adults. In addition, as control efforts intensify and the number of interventions increases, there will be decreases in prevalence, incidence and transmission with additional decreases in morbidity and mortality. Expected secondary consequences of these changes include upward shifts in the peak ages for infection (parasitemia) and disease, increases in the ages for acquisition of antiparasite humoral and cellular immune responses and increases in false-negative blood smears and rapid diagnostic tests. Strategies to monitor these changes must include: (1) studies of the entire population (that are not restricted to children ≤5 or ≤10 years of age), (2) study sites in both cities and rural areas (because of increasing urbanization across sub-Saharan Africa) and (3) innovative strategies for surveillance as the prevalence of infection decreases and the frequency of false-negative smears and rapid diagnostic tests increases.
Subject(s)
Communicable Disease Control/methods , Disease Transmission, Infectious/prevention & control , Malaria, Falciparum/prevention & control , Plasmodium falciparum/pathogenicity , Africa, Western/epidemiology , Animals , Anopheles/parasitology , Antibodies, Protozoan/immunology , Antimalarials/pharmacology , Communicable Disease Control/legislation & jurisprudence , Communicable Disease Control/organization & administration , Drug Resistance, Microbial , Genotype , Humans , Immunity, Cellular , Incidence , Malaria, Falciparum/epidemiology , Malaria, Falciparum/immunology , Malaria, Falciparum/parasitology , National Health Programs/organization & administration , Parasitemia/epidemiology , Parasitemia/immunology , Parasitemia/parasitology , Parasitemia/prevention & control , Plasmodium falciparum/drug effects , Plasmodium falciparum/genetics , Plasmodium falciparum/immunology , Prevalence , Seasons , Sensitivity and SpecificityABSTRACT
The study sites for the West African ICEMR are in three countries (The Gambia, Senegal, Mali) and are located within 750 km of each other. In addition, the National Malaria Control Programmes of these countries have virtually identical policies: (1) Artemisinin Combination Therapies (ACTs) for the treatment of symptomatic Plasmodium falciparum infection, (2) Long-Lasting Insecticide-treated bed Nets (LLINs) to reduce the Entomololgic Inoculation Rate (EIR), and (3) sulfadoxine-pyrimethamine for the Intermittent Preventive Treatment of malaria during pregnancy (IPTp). However, the prevalence of P. falciparum malaria and the status of malaria control vary markedly across the four sites with differences in the duration of the transmission season (from 4-5 to 10-11 months), the intensity of transmission (with EIRs from unmeasurably low to 4-5 per person per month), multiplicity of infection (from a mean of 1.0 to means of 2-5) and the status of malaria control (from areas which have virtually no control to areas that are at the threshold of malaria elimination). The most important priority is the need to obtain comparable data on the population-based prevalence, incidence and transmission of malaria before new candidate interventions or combinations of interventions are introduced for malaria control.
Subject(s)
Communicable Disease Control/legislation & jurisprudence , Health Policy/legislation & jurisprudence , Malaria, Falciparum/prevention & control , Africa, Western/epidemiology , Animals , Antimalarials/pharmacology , Artemisinins/pharmacology , Communicable Disease Control/organization & administration , Culicidae/drug effects , Culicidae/parasitology , Disease Transmission, Infectious/prevention & control , Drug Combinations , Female , Humans , Insect Bites and Stings/parasitology , Insecticide-Treated Bednets , Insecticides/pharmacology , Malaria, Falciparum/drug therapy , Malaria, Falciparum/epidemiology , Malaria, Falciparum/parasitology , National Health Programs/legislation & jurisprudence , National Health Programs/organization & administration , Plasmodium falciparum/pathogenicity , Pregnancy , Pregnancy Complications, Parasitic/drug therapy , Pregnancy Complications, Parasitic/parasitology , Pregnancy Complications, Parasitic/prevention & control , Prevalence , Pyrimethamine/therapeutic use , Seasons , Sulfadoxine/therapeutic useABSTRACT
Success of the global research agenda toward eradication of malaria will depend on development of new tools, including drugs, vaccines, insecticides and diagnostics. Genomic information, now available for the malaria parasites, their mosquito vectors, and human host, can be leveraged to both develop these tools and monitor their effectiveness. Although knowledge of genomic sequences for the malaria parasites, Plasmodium falciparum and Plasmodium vivax, have helped advance our understanding of malaria biology, simply knowing this sequence information has not yielded a plethora of new interventions to reduce the burden of malaria. Here we review and provide specific examples of how genomic information has increased our knowledge of parasite biology, focusing on P. falciparum malaria. We then discuss how population genetics can be applied toward the epidemiological and transmission-related goals outlined by the International Centers of Excellence for Malaria Research groups recently established by the National Institutes of Health. Finally, we propose genomics is a research area that can promote coordination and collaboration between various ICEMR groups, and that working together as a community can significantly advance the value of this information toward reduction of the global malaria burden.
Subject(s)
Genome, Protozoan , Genomics , International Cooperation , Malaria, Falciparum/prevention & control , Research/organization & administration , Animals , Disease Eradication/methods , Disease Eradication/organization & administration , Disease Transmission, Infectious/prevention & control , Genetic Markers , Genetic Variation , Humans , Insect Vectors/parasitology , Malaria, Falciparum/epidemiology , Malaria, Falciparum/parasitology , Plasmodium falciparum/genetics , Plasmodium falciparum/pathogenicity , Research DesignABSTRACT
DSL proteins are transmembrane ligands of the Notch receptor. They associate with a RING (really interesting new gene) family E3 ubiquitin ligase, either Neuralized (Neur) or Mindbomb 1 (Mib1), as a prerequisite to signaling. Although Neur and Mib1 stimulate internalization of DSL ligands, it is not known how ubiquitylation contributes to signaling. We present a molecular dissection of the intracellular domain (ICD) of Drosophila melanogaster Delta (Dl), a prototype DSL protein. Using a cell-based assay, we detected ubiquitylation of Dl by both Neur and Mib1. The two enzymes use distinct docking sites and displayed different acceptor lysine preferences on the Dl ICD. We generated Dl variants that selectively perturb its interactions with Neur or Mib1 and analyzed their signaling activity in two in vivo contexts. We found an excellent correlation between the ability to undergo ubiquitylation and signaling. Therefore, ubiquitylation of the DSL ICD seems to be a necessary step in the activation of Notch.
Subject(s)
Drosophila Proteins/metabolism , Drosophila melanogaster/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Membrane Proteins/metabolism , Ubiquitin-Protein Ligases/metabolism , Ubiquitination , Amino Acid Motifs , Animals , Catalytic Domain , Endocytosis , Receptors, Notch/metabolism , Signal TransductionABSTRACT
Discriminating among sensory stimuli is critical for animal survival. This discrimination is particularly essential when evaluating whether a stimulus is noxious or innocuous. From insects to humans, transient receptor potential (TRP) channels are key transducers of thermal, chemical and other sensory cues. Many TRPs are multimodal receptors that respond to diverse stimuli, but how animals distinguish sensory inputs activating the same TRP is largely unknown. Here we determine how stimuli activating Drosophila TRPA1 are discriminated. Although Drosophila TRPA1 responds to both noxious chemicals and innocuous warming, we find that TRPA1-expressing chemosensory neurons respond to chemicals but not warmth, a specificity conferred by a chemosensory-specific TRPA1 isoform with reduced thermosensitivity compared to the previously described isoform. At the molecular level, this reduction results from a unique region that robustly reduces the channel's thermosensitivity. Cell-type segregation of TRPA1 activity is critical: when the thermosensory isoform is expressed in chemosensors, flies respond to innocuous warming with regurgitation, a nocifensive response. TRPA1 isoform diversity is conserved in malaria mosquitoes, indicating that similar mechanisms may allow discrimination of host-derived warmth--an attractant--from chemical repellents. These findings indicate that reducing thermosensitivity can be critical for TRP channel functional diversification, facilitating their use in contexts in which thermal sensitivity can be maladaptive.