Biology subjects

Marti, M.

Publications and source records attributed to Marti, M..

At least 19 recordsLinked to original sources

bioRxiv2026

Severe malarial anaemia is associated with parasite enrichment and host alterations in the bone marrow

BackgroundMalaria poses a significant global health challenge, with over 200 million infections and around 500,000 deaths annually, predominantly affecting children under 5 in sub-Saharan Africa. Severe malarial anaemia (SMA), a major contributor to morbidity and mortality in this demographic, results from various factors including red blood cell destruction and immune-mediated clearance. The role of these mechanisms in SMA differs based on age and infection history. Recent studies indicate increased accumulation of P. falciparum in the bone marrow and spleen, highlighting the need for understanding localized host-parasite interactions. MethodsThis study examines the bone marrow response to malarial infection in young children with SMA or mild malarial malaria in Mozambique, contrasting it with responses observed in peripheral blood in the two cohorts. Results and conclusionsThe study demonstrated that SMA is associated with increased red blood cell production, iron metabolism and tissue injury, as well as higher total parasite biomass including peripheral and bone marrow parasitaemia. We also demonstrate that direct analysis of bone marrow aspirates provides far more resolution in stratifying host signatures and drivers of malarial anaemia across a spectrum of severity than systemic measures from blood samples.

microbiology↗

bioRxiv2026

Solving the Diagnostic Odyssey with Synthetic Phenotype Data

The space of possible phenotype profiles over the Human Phenotype Ontology (HPO) is combinatorially vast, whereas the space of candidate disease genes is far smaller. Phenotype-driven diagnosis is therefore highly non-bijective: many distinct symptom profiles can correspond to the same gene, but only a small fraction of the theoretical phenotype space is biologically and clinically plausible. When a structured ontology exists, this constraint can be exploited to generate realistic synthetic cases. We introduce GraPhens, a simulation framework that uses gene-local HPO structure together with two empirically motivated soft priors, over the number of observed phenotypes per case and phenotype specificity, to generate synthetic phenotype-gene pairs that are novel yet clinically plausible. We use these synthetic cases to train GenPhenia, a graph neural network that reasons over patient-specific phenotype subgraphs rather than flat phenotype sets. Despite being trained entirely on synthetic data, GenPhenia generalizes to real, previously unseen clinical cases and outperforms existing phenotype-driven gene-prioritization methods on two real-world datasets. These results show that when patient-level data are scarce but a structured ontology is available, principled simulation can provide effective training data for end-to-end neural diagnosis models.

bioinformatics↗

bioRxiv2025

Regional adaptation to mosquito vectors shapes Plasmodium falciparum populations

Transmission of Plasmodium falciparum through mosquitoes represents the most severe population bottleneck in the parasites life cycle, yet the genetic basis of parasite-vector compatibility remains poorly understood. Here, we show that mosquito species-specific transmissibility depends on allelic variation in multiple P. falciparum genes expressed during midgut invasion, beyond the well-studied Pfs47. Using an allelic replacement strategy, we targeted highly geographically differentiated SNPs in P. falciparum that match regional variation in vector community composition. Transmissibility was compared across four mosquito species representing distinct geographic ranges (An. gambiae, An. stephensi, An. minimus, and An. albimanus). Two of five tested polymorphisms showed increased oocyst and sporozoite burdens in sympatric parasite-vector combinations compared to allopatric ones. Both substitutions occurred in ookinete micronemal proteins, CTRP and WARP, within von Willebrand factor A domains, suggesting that regional allelic variation modulates Plasmodium-vector compatibility by altering midgut adhesion interactions. These findings reveal that vector compatibility is a polygenic trait shaped by molecular interactions across several loci. Understanding this complexity refines models of parasite adaptation and can inform the design of transmission-blocking interventions effective across diverse vector-parasite combinations.

microbiology↗

bioRxiv2024

Reversible host cell surface remodelling limits immune recognition and maximizes transmission of Plasmodium falciparum gametocytes

Reducing malaria transmission has been a major pillar of control programmes and is considered crucial for achieving malaria elimination. Gametocytes, the transmissible forms of the P. falciparum parasite, arise during the blood stage of the parasite and develop through 5 morphologically distinct stages. Immature gametocytes (stage I-IV) sequester and develop in the extravascular niche of the bone marrow and possibly spleen. Only mature stage V gametocytes re-enter peripheral circulation to be taken up by mosquitoes for successful onward transmission. We have recently shown that immature, but not mature gametocytes are targets of host immune responses and identified putative target surface antigens. We hypothesize that these antigens play a role in gametocyte sequestration and contribute to acquired transmission-reducing immunity. Here we demonstrate that surface antigen expression, serum reactivity by human IgG, and opsonic phagocytosis by macrophages all show similar dynamics during gametocyte maturation, i.e., on in immature and off in mature gametocytes. Moreover, the switch in surface reactivity coincides with reversal in phosphatidylserine (PS) surface exposure, a marker for red blood cell age and clearance. PS is exposed on the surface of immature gametocytes (as well as in late asexual stages) but is removed from the surface in later gametocyte stages (IV-V). Using parasite reverse genetics and drug perturbations, we confirm that parasite protein export into the host cell and phospholipid scramblase activity are required for the observed surface modifications in asexual and sexual P. falciparum stages. These findings suggest that the dynamic surface remodelling allows (i) immature gametocyte sequestration in bone marrow and (ii) mature gametocyte release into peripheral circulation and immune evasion, therefore contributing to mature gametocyte survival in vivo and onward transmission to mosquitoes. Importantly, blocking scramblase activity during gametocyte maturation results in efficient clearance of mature gametocytes, revealing a potential path for transmission blocking interventions. Our studies have important implications for our understanding of parasite biology and form a starting point for novel intervention strategies to simultaneously reduce parasite burden and transmission. IMPORTANTO_LIManuscripts submitted to Review Commons are peer reviewed in a journal-agnostic way. C_LIO_LIUpon transfer of the peer reviewed preprint to a journal, the referee reports will be available in full to the handling editor. C_LIO_LIThe identity of the referees will NOT be communicated to the authors unless the reviewers choose to sign their report. C_LIO_LIThe identity of the referee will be confidentially disclosed to any affiliate journals to which the manuscript is transferred. C_LI GUIDELINESO_LIFor reviewers: https://www.reviewcommons.org/reviewers C_LIO_LIFor authors: https://www.reviewcommons.org/authors C_LI CONTACTThe Review Commons office can be contacted directly at: office@reviewcommons.org

microbiology↗

bioRxiv2023

A non-canonical Arp2/3 complex is essential for Plasmodium DNA segregation and transmission of malaria.

The malaria-causing parasite Plasmodium has a complex life cycle involving both vertebrate and mosquito hosts. Sexual stages or gametocytes are the only stage competent for transmission to mosquitoes. Formation of flagellated male gametes from gametocytes requires rapid rounds of genome replication. Here we discovered a non-canonical Plasmodium actin-related protein 2/3 (Arp2/3) complex essential for DNA segregation during male gametogenesis. Plasmodium Arp2/3 dynamically localizes within the nucleus to the endomitotic spindles and interacts with a kinetochore protein. Deletion of key Arp2/3 subunits or interfering with actin polymerisation leads to the formation of sub-haploid male gametes and a complete block in transmission through delayed developmental arrest at the oocyst stage. Our work identified an evolutionary divergent protein complex in malaria parasites that offers potential targets for transmission-blocking interventions.

microbiology↗

bioRxiv2023

Repeated Plasmodium vivax blood stage infection provides sterile protection against homologous challenge in non-human primates

The malaria parasite Plasmodium vivax remains a major global public health challenge, causing major morbidity across tropical and subtropical regions. Several candidate vaccines are in preclinical and clinical trials, however no vaccine against P. vivax malaria is approved for use in humans. Here we assessed whether P. vivax strain-transcendent immunity can be achieved by repeated infection in Aotus monkeys. For this purpose, we repeatedly infected six animals with blood stages of the P. vivax Salvador 1 (SAL-1) strain until sterile immune, and then challenged with the AMRU-1 strain. Sterile immunity was achieved in 4/4 Aotus monkeys after two homologous infections with the SAL-1 strain, while partial protection against a heterologous AMRU-1 challenge (i.e., delay to infection and reduction in peak parasitemia compared to control) was achieved in 3/3 monkeys. IgG levels based on P. vivax lysate ELISA and protein microarray increased with repeated infections and correlated with the level of homologous protection. Analysis of parasite transcriptional profiles across inoculation levels provided no evidence of major antigenic switching upon homologous or heterologous challenge. In contrast, we observed significant transcriptional differences in the P. vivax core gene repertoire between SAL-1 and AMRU-1. Together with the strain-specific genetic diversity between SAL-1 and AMRU-1 these data suggest that the partial protection upon heterologous challenge is due to molecular differences between strains (at genome and transcriptome level) rather than immune evasion by antigenic switching. Our study demonstrates that sterile immunity against P. vivax can be achieved by repeated homologous blood stage infection in Aotus monkeys, thus providing a benchmark to test the efficacy of candidate blood stage P. vivax malaria vaccines. Author summaryPlasmodium vivax is the most widespread human malaria parasite. Elimination efforts are complicated due to the peculiar biology of P. vivax including dormant liver forms, cryptic reservoirs in bone marrow and spleen and a large asymptomatic infectious reservoir in affected populations. Currently there is no vaccine against malaria caused by P. vivax. Here we induce sterile immunity by repeated P. vivax infection with the SAL-1 strain in non-human primates. In contrast, heterologous challenge with the AMRU-1 strain only provided partial protection. Antibody levels against a crude antigen and a protein microarray correlated with the level of homologous protection. Parasite transcriptional profiles across inoculation levels failed to show major antigenic switching across SAL-1 infections or upon heterologous challenge, instead suggesting other mechanisms of immune evasion. Our study demonstrates that sterile immunity against P. vivax can be achieved by repeated blood stage infection in Aotus monkeys, thus providing a benchmark to test the efficacy of candidate blood stage P. vivax malaria vaccines.

microbiology↗

bioRxiv2022

FKBP35 secures ribosome homeostasis in Plasmodium falciparum

Plasmodium falciparum accounts for the majority of over 600000 malaria-associated deaths annually. Parasites resistant to nearly all antimalarials have emerged and the need for drugs with alternative modes of action is thus undoubted. The FK506-binding protein PfFKBP35 has gained attention as a promising drug target due to its high affinity to the macrolide compound FK506 (tacrolimus). Whilst there is considerable interest in targeting PfFKBP35 with small molecules, a genetic validation of this factor as a drug target is missing and its function in parasite biology remains elusive. Here, we show that limiting PfFKBP35 levels are lethal to P. falciparum and result in a delayed death-like phenotype that is characterized by defective ribosome homeostasis and stalled protein synthesis. Our data furthermore suggest that FK506, unlike the action of this drug in model organisms, exerts its anti-proliferative activity in a PfFKBP35-independent manner and, using cellular thermal shift assays, we identify putative FK506-targets beyond PfFKBP35. In addition to revealing first insights into the function of PfFKBP35, our results show that FKBP-binding drugs can adopt non-canonical modes of action - with major implications for the development of FK506-derived molecules active against Plasmodium parasites and other eukaryotic pathogens.

molecular biology↗

bioRxiv2022

Plasmodium falciparum adapts its investment into replication versus transmission according to the host environment

The malaria parasite life cycle includes asexual replication in human blood, with a proportion of parasites differentiating to gametocytes required for transmission to mosquitoes. Commitment to differentiate into gametocytes, which is marked by activation of the parasite transcription factor ap2-g, is known to be influenced by host factors but a comprehensive model remains uncertain. Here we analyze data from 828 children in Kilifi, Kenya with severe, uncomplicated, and asymptomatic malaria infection over 18 years of falling malaria transmission. We examine markers of host immunity and metabolism, and markers of parasite growth and transmission investment. We find that inflammatory responses and reduced plasma lysophosphatidylcholine levels are associated with markers of increased investment in parasite sexual reproduction (i.e., transmission investment) and reduced growth (i.e., asexual replication). This association becomes stronger with falling transmission and suggests that parasites can rapidly respond to the within-host environment, which in turn is subject to changing transmission.

microbiology↗

bioRxiv2022

A quinolin-8-ol sub-millimolar inhibitor of UGGT, the ER glycoprotein folding quality control checkpoint

The Endoplasmic Reticulum (ER) glycoprotein folding Quality Control (ERQC) machinery aids folding of glycoproteins in the ER. Misfolded glycoprotein recognition and ER-retention is mediated by the ERQC checkpoint enzyme, the 170 kDa UDP-Glucose glycoprotein glucosyltransferase (UGGT). UGGT modulation is a promising strategy for broad-spectrum antivirals, rescue-of-secretion therapy in rare disease caused by responsive mutations in glycoprotein genes, and many cancers, but to date no selective UGGT inhibitors are known. Towards the generation of selective UGGT inhibitors, we determined the crystal structures of the catalytic domain of Chaetomium thermophilum UGGT (CtUGGTGT24), alone and in complex with the inhibitor UDP-2-deoxy-2-fluoro-D-glucose (U2F). Using the CtUGGTGT24 crystals, we carried out a fragment-based lead discovery screen via X-ray crystallography and discovered that the small molecule 5-[(morpholin-4-yl)methyl]quinolin-8-ol (5M-8OH-Q) binds a CtUGGTGT24 WY conserved surface motif that is not present in other GT24 family glycosyltransferases. The 5M-8OH-Q molecule has a 613 {micro}M binding affinity for human UGGT1in vitro as measured by saturation transfer difference NMR spectroscopy. The 5M-8OH-Q molecule inhibits both human UGGT1and UGGT2 activity at concentrations higher than 750 {micro}M in modified HEK293-6E cells. The compound is toxic in cellula and in planta at concentrations higher than 1 mM. A few off-target effects are also observed upon 5M-8OH-Q treatment. Based on an in silico model of the interaction between UGGT and its substrate N -glycan, the 5M-8OH-Q molecule likely works as a competitive inhibitor, binding to the site of recognition of the first GlcNAc residue of the substrate N -glycan. Significance StatementWhen a candidate drug target is the product of a housekeeping gene - i.e. it is important for the normal functioning of the healthy cell - availability of inhibitors for tests and assays is of paramount importance. One such housekeeping protein is UGGT, the enzyme that makes sure that only correctly folded glycoproteins can leave the endoplasmic reticulum for further trafficking through the secretory pathway. UGGT is a potential drug target against viruses, in certain instances of congenital rare disease, and against some cancers, but no UGGT inhibitors are known yet. We discovered and describe here a small molecule that binds human UGGT1 in vitro and inhibits both isoforms of human UGGT in cellula. The compound paves the way to testing of UGGT inhibition as a potential pharmacological strategy in a number of medical contexts.

biochemistry↗

bioRxiv2021

Molecular basis of unidirectional information transmission in two-component systems: lessons from the DesK-DesR thermosensor

Cellular signaling systems transmit information over long distances using allosteric transitions and/or post-translational modifications. In two-component systems the sensor histidine kinase and response regulator are wired through phosphoryl-transfer reactions, using either a uni- or bi-directional transmission mode, allowing to build rich regulatory networks. Using the thermosensor DesK-DesR two-component system from Bacillus subtilis and combining crystal structures, QM/MM calculations and integrative kinetic modeling, we uncover that: i) longer or shorter distances between the phosphoryl-acceptor and -donor residues can shift the phosphoryl-transfer equilibrium; ii) the phosphorylation-dependent dimerization of the regulator acts as a sequestering mechanism by preventing the interaction with the histidine kinase; and iii) the kinases intrinsic conformational equilibrium makes the phosphotransferase state unlikely in the absence of histidine phosphorylation, minimizing backwards transmission. These mechanisms allow the system to control the direction of signal transmission in a very efficient way, showcasing the key role that structure-encoded allostery plays in signaling proteins to store and transmit information.

biophysics↗

bioRxiv2021

Antiviral face mask functionalized with solidified hand soap: low-cost infection prevention clothing against enveloped viruses such as SARS-CoV-2

Infection prevention clothing is becoming an essential protective tool in the current pandemic, especially because now we know that SARS-CoV-2 can easily infect humans in poorly ventilated indoor spaces. However, commercial infection prevention clothing is made of fabrics that are not capable of inactivating the virus. Therefore, viral infections of symptomatic and asymptomatic individuals wearing protective clothing such as masks can occur through aerosol transmission or by contact with the contaminated surfaces of the masks, which are suspected as an increasing source of highly infectious biological waste. Herein, we report an easy fabrication method of a novel antiviral non-woven fabric containing polymer filaments that were coated with solidified hand soap. This extra protective fabric is capable of inactivating enveloped viruses such as SARS-CoV-2 and phi 6 in one minute of contact. In this study, this antiviral fabric was used to fabricate an antiviral face mask and did not show any cytotoxic effect in human keratinocyte HaCaT cells. Furthermore, this antiviral non-woven fabric could be used for the fabrication of other infection prevention clothing such as caps, scrubs, shirts, trousers, disposable gowns, overalls, hoods, aprons, and shoe covers. Therefore, this low-cost technology could provide a wide range of infection protective tools to combat COVID-19 and future pandemics in developed and underdeveloped countries.

bioengineering↗

bioRxiv2021

Next generation infection prevention clothing: Non-woven Fabrics Coated with Cranberry Extracts Capable of Inactivating Enveloped Viruses such as SARS-CoV-2 and Multidrug-resistant Bacteria

The Coronavirus Disease (COVID-19) pandemic is demanding rapid action of the authorities and scientific community in order to find new antimicrobial solutions that could inactivate the pathogen SARS-CoV-2 that causes this disease. Gram-positive bacteria contribute to severe pneumonia associated with COVID-19, and their resistance to antibiotics is increasing at an alarming rate. In this regard, non-woven fabrics are currently used for the fabrication of infection prevention clothing such as face masks, caps, scrubs, shirts, trousers, disposable gowns, overalls, hoods, aprons and shoe covers as protective tools against viral and bacterial infections. However, these non-woven fabrics are made of materials that do not possess antimicrobial activity. Thus, we have developed here non-woven fabrics with antimicrobial coatings of cranberry extracts capable of inactivating enveloped viruses such as SARS-CoV-2 and the phage phi 6, and two multidrug-resistant bacteria: the methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis. The non-toxicity of these advanced technology was ensured using a Caenorhabditis elegans in vivo model. These results open up a new prevention path using natural and biodegradable compounds for the fabrication of infection prevention clothing in the current COVID-19 and future pandemics.

bioengineering↗

bioRxiv2021

From contigs to chromosomes: automatic Improvement of Long Read Assemblies (ILRA)

Recent advances in long read technologies not only enable large consortia to aim to sequence all eukaryotes on Earth, but they also allow individual laboratories to sequence their species of interest with relatively low investment. Although there is a promise of long read technologies to obtain "perfect genomes", the number of contigs often exceeds the number of chromosomes by far, containing many insertion and deletion errors around homopolymer tracks. To overcome these issues, we implemented the ILRA pipeline to correct long read-based assemblies, so contigs are reordered, renamed, merged, circularized, or filtered if erroneous or contaminated, and Illumina reads are used to correct homopolymer errors. We successfully tested our approach by improving the genomes of Trypanosoma brucei and Leptosphaeria spp, and generated four novel Plasmodium falciparum assemblies from field samples. We found that correcting homopolymer tracks reduced the number of genes incorrectly annotated as pseudogenes, but an iterative correction seems to be required to correct larger numbers of sequencing errors. In summary, we described and compared the performance of our new tool, which improved the quality of novel long read assemblies of genomes up to 1Gbp. AvailabilityThe tool is available at GitHub: https://github.com/ThomasDOtto/ILRA.

bioinformatics↗

bioRxiv2021

3D printed cobalt-chromium-molybdenum porous superalloy with superior antiviral activity

COVID-19 pandemic and associated supply-chain disruptions emphasise the requirement for antimicrobial materials for on-demand manufacturing. Besides aerosol transmission, SARS-CoV-2 is also propagated through contact with virus-contaminated surfaces. As such, the development of effective biofunctional materials that can inactivate SARS-CoV-2 are critical for pandemic preparedness. Such materials will enable the rational development of antiviral devices with prolonged serviceability reducing the environmental burden of disposable alternatives. This research reveals the novel use of Laser Powder Bed Fusion (LPBF) to 3D print porous Cobalt-Chromium-Molybdenum (Co-Cr-Mo) superalloy with potent antiviral activity (100% viral inactivation in 30 mins). The porous material was rationally conceived using a multi-objective surrogate model featuring track thickness (tt) and pore diameter ({phi}d) as responses. The regression analysis found the most significant parameters for Co-Cr-Mo track formation to be the interaction effects of scanning rate (Vs) and laser power (Pl) in the order PlVs > Vs > Pl. Contrastively, the pore diameter was found to be primarily driven by the hatch spacing (Sh). The study is the first to demonstrate the superior antiviral properties of 3D printed Co-Cr-Mo superalloy against an enveloped virus used as biosafe viral model of SARS-CoV-2. The material significantly outperforms the viral inactivation time of other broadly used antiviral metals such as copper and silver from 5 hours to 30 minutes. As such the study goes beyond the current state-of-the-art in antiviral alloys to provide extra-protection to combat the SARS-COV-2 viral spread. The evolving nature of the COVID-19 pandemic brings new and unpredictable challenges where on-demand 3D printing of antiviral materials can achieve rapid solutions while reducing the environmental impact of disposable devices. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=148 SRC="FIGDIR/small/454385v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@992f2forg.highwire.dtl.DTLVardef@e8dbe5org.highwire.dtl.DTLVardef@1bcb8adorg.highwire.dtl.DTLVardef@100a345_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2021

Host cell maturation modulates parasite invasion and sexual differentiation in Plasmodium.

Malaria remains a global health problem with over 400,000 deaths annually1. Plasmodium parasites, the causative agents of malaria, replicate asexually in red blood cells (RBCs) of their vertebrate host, while a subset differentiates into sexual stages (gametocytes) for mosquito transmission. Parasite replication and gametocyte maturation in the erythropoietic niches of the bone marrow and spleen contribute to pathogenesis and drive transmission2, but the mechanisms underlying this organ enrichment remain unknown. We performed a comprehensive single cell analysis of rodent P. berghei in spleen, bone marrow and blood to define parasite phenotypes specific to those niches. Single cell RNA-seq analysis of host and parasite cells reveals an interferon-driven host response to infection as well as transcriptional adaptations of Plasmodium to RBC maturation status. We show that P. berghei exhibits a bimodal invasion pattern into either normocytes or early reticulocytes and, using functional assays, identify CD71 as a host receptor for reticulocyte invasion. Importantly, we observe an increased rate of gametocyte formation in reticulocytes that is nutrient-dependent and triggered post invasion (i.e., same cycle sexual commitment). Our data provides a thorough characterisation of host-parasite interactions in erythropoietic niches and defines host cell maturation state as the key driver of parasite adaptation.

microbiology↗

bioRxiv2021

Carotenoid and tocopherol fortification of zucchini fruits using a viral RNA vector

Carotenoids and tocopherols are health-promoting metabolites in livestock and human diets. Some important crops have been genetically modified to increase their content. Although the usefulness of transgenic plants to alleviate nutritional deficiencies is obvious, their social acceptance has been controversial. Here, we demonstrate an alternative biotechnological strategy for carotenoid and tocopherol fortification of edible fruits in which no transgenic DNA is involved. A viral RNA vector derived from Zucchini yellow mosaic virus (ZYMV) was modified to express a bacterial phytoene synthase (crtB), and inoculated in zucchini (Cucurbita pepo L.) leaves nurturing pollinated flowers. After the viral vector moved to the developing fruit and expressed crtB, the rind and flesh of the fruits developed yellow-orange rather than green color. Metabolite analyses showed a substantial enrichment in health-promoting carotenoids, such as - and {beta}-carotene (pro-vitamin A), lutein and phytoene, in both rind and flesh. Considerably higher accumulation of - and {gamma}-tocopherol was also detected, particularly in fruit rind. Although this strategy is perhaps not free from controversy due to the use of genetically modified viral RNA, our work does demonstrate the possibility of metabolically fortifying edible fruits using an approach in which no transgenes are involved.

plant biology↗

bioRxiv2020

Protective face mask filter capable of inactivating SARS-CoV-2, and methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis

Face masks have globally been accepted to be an effective protective tool to prevent bacterial and viral transmission, especially against indoor aerosol transmission. However, commercial face masks contain filters that are made of materials that are not capable of inactivating neither SARS-CoV-2 nor multidrug-resistant bacteria. Therefore, symptomatic and asymptomatic individuals can infect other people even if they wear them because some viable viral or bacterial loads can escape from the masks. Furthermore, viral or bacterial contact transmission can occur after touching the mask, which constitutes an increasing source of contaminated biological waste. Additionally, bacterial pathogens contribute to the SARS-CoV-2 mediated pneumonia disease complex and their resistance to antibiotics in pneumonia treatment is increasing at an alarming rate. In this regard, herein, we report the development of a novel protective non-woven face mask filter fabricated with a biofunctional coating of benzalkonium chloride that is capable of inactivating SARS-CoV-2 in one minute of contact, and the life-threatening methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis. Nonetheless, despite the results obtained, further studies are needed to ensure the safety and correct use of this technology for the mass production and commercialization of this broad-spectrum antimicrobial face mask filter. Our novel protective non-woven face mask filter would be useful for many health care workers and researchers working in this urgent and challenging field.

bioengineering↗

bioRxiv2020

Population Genomics of Plasmodium vivax in Panama to Assess the Risk of Case Importation on Malaria Elimination

Malaria incidence in Panama has plateaued in recent years in spite of elimination efforts, with almost all cases caused by Plasmodium vivax. Notwithstanding, overall malaria prevalence remains low (fewer than 1 case per 1000 persons). We used selective whole genome amplification to sequence 96 P. vivax samples from Panama collected between 2007 and 2019 to study the population structure and transmission dynamics of the parasite. Imported cases resulting from increased levels of human migration could threaten malaria elimination prospects, and four of the samples evaluated came from individuals with travel history. We explored patterns of recent common ancestry among the samples and observed that a single highly genetically related lineage was dominant among the samples (47 out of 59 samples with good sequencing coverage), spanning the entire period of the collection (2007-2019) and all regions of the country. We also found a second, smaller clonal lineage of four parasites collected between 2017 and 2019. To explore the regional context of Panamanian P. vivax we conducted principal components analysis and constructed a neighbor-joining tree using these samples and samples collected worldwide from a previous study. Three of the four samples with travel history clustered with samples collected from their suspected country of origin (consistent with importation), while one appears to have been a result of local transmission. The small number of genetically unique Panamanian P. vivax samples clustered with samples collected from Colombia, suggesting they represent the genetically similar ancestral P. vivax population in Panama or were recently imported from Colombia. The low diversity we observe in Panama indicates that this parasite population has been previously subject to a severe bottleneck and may be eligible for elimination. Additionally, while we confirmed that P. vivax is imported to Panama from diverse geographic locations, the lack of impact from imported cases on the overall parasite population genomic profile suggests that onward transmission from such cases is limited and that imported cases may not presently pose a major barrier to elimination. Author SummaryPanama has greatly reduced P. vivax incidence, however, this progress has plateaued. Understanding parasite transmission patterns and identifying imported cases is critical to help Panama and other countries succeed in their elimination efforts. Genomic epidemiology and population genomics can help provide information needed to inform malaria control policy. In this study, we collected 100 Panamanian P. vivax samples from two collection periods (2007-2009 and 2017-2019), of which 59 yielded usable sequencing data. 4 samples had patient travel history data associated with them. We found that the majority of samples belong to a single highly related lineage, termed CL1. This lineage has persisted since at least 2007. We also highlight how genomic epidemiology can be used to spotlight parasites that may be imported as a result of human migration, as well as corroborate or refute the country of origin as suggested by patient travel history. We observe no evidence of outcrossing between these potentially imported parasites and the local Panamanian parasite population, suggesting that imported parasites are not driving ongoing malaria transmission in Panama. The low diversity we observe in Panama indicates that this parasite population has been previously subject to a severe bottleneck and may be eligible for elimination.

microbiology↗