Jan Strauss | European Molecular Biology Laboratory (original) (raw)

Papers by Jan Strauss

Nature Ecology & Evolution

The Microbiomes of Humans, Animals, Plants, and the Environment, 2022

Communications Biology

Merozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria ... more Merozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria parasite Plasmodium falciparum. Proteins involved with RBC binding and invasion are secreted from dual-club shaped organelles at the apical tip of the merozoite called the rhoptries. Here we characterise P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 2 (PfCERLI2), as a rhoptry bulb protein that is essential for merozoite invasion. Phylogenetic analyses show that cerli2 arose through an ancestral gene duplication of cerli1. We show that PfCERLI2 is essential for blood-stage growth and localises to the cytosolic face of the rhoptry bulb. Inducible knockdown of PfCERLI2 led to a proportion of merozoites failing to invade and was associated with elongation of the rhoptry organelle during merozoite development and inhibition of rhoptry antigen processing. These findings identify PfCERLI2 as a protein that has key roles in rhoptry biology during merozoite invasion.

Abstract. The malacological collections of the German Oceanographic Museum (GOM) in Stralsund and... more Abstract. The malacological collections of the German Oceanographic Museum (GOM) in Stralsund and the Zoological Museum of the University Rostock (ZSRO) keep Cephalopod specimens from all over the world. The inventory and taxonomic revision presented in this study provides an overview of the cephalopod samples present in both collections. The total of 252 specimen records (GOM: 193, ZSRO: 59) represent 51 different species, mainly from northern Atlantic, Mediterranean and western Pacific locations. Special reference is made to species collected from the North Sea. Kurzfassung. In den wissenschaftlichen Mollusken-Sammlungen des Deutschen Meeresmuseums (DMM) in Stralsund und der Zoologischen Sammlung Rostock (ZSRO) werden Cephalopoden-Exemplare aus allen Teilen des Weltmeeres aufbewahrt. Die vorliegende Inventur und taxonomische Revision gibt einen Überblick über das vorhandene Sammlungsmaterial. Unter insgesamt 252

Membrane transport proteins perform crucial roles in cell physiology. The obligate intracellular ... more Membrane transport proteins perform crucial roles in cell physiology. The obligate intracellular parasite Plasmodium falciparum, an agent of human malaria, relies on membrane transport proteins for the uptake of nutrients from the host, disposal of metabolic waste, exchange of metabolites between organelles and generation and maintenance of transmembrane electrochemical gradients for its growth and replication within human erythrocytes. Despite their importance for Plasmodium cellular physiology, the functional roles of a number of membrane transport proteins remain unclear, which is particularly true for orphan membrane transporters that have no or limited sequence homology to transporter proteins in other evolutionary lineages. Therefore, in the current study, we applied endogenous tagging, targeted gene disruption, conditional knockdown and knockout approaches to investigate the subcellular localization and essentiality of six membrane transporters during intraerythrocytic develo...

mSphere

Malaria parasites live and multiply inside cells. To facilitate their extremely fast intracellula... more Malaria parasites live and multiply inside cells. To facilitate their extremely fast intracellular proliferation, they hijack and transform their host cells.

The Southern Ocean houses a diverse and productive community of organisms 1,2. Unicellular eukary... more The Southern Ocean houses a diverse and productive community of organisms 1,2. Unicellular eukaryotic diatoms are the main primary producers in this environment, where photosynthesis is limited by low concentrations of dissolved iron and large seasonal fluctuations in light, temperature and the extent of sea ice 3-7. How diatoms have adapted to this extreme environment is largely unknown. Here we present insights into the genome evolution of a cold-adapted diatom from the Southern Ocean, Fragilariopsis cylindrus 8,9 , based on a comparison with temperate diatoms. We find that approximately 24.7 per cent of the diploid F. cylindrus genome consists of genetic loci with alleles that are highly divergent (15.1 megabases of the total genome size of 61.1 megabases). These divergent alleles were differentially expressed across environmental conditions, including darkness, low iron, freezing, elevated temperature and increased CO 2. Alleles with the largest ratio of non-synonymous to synonymous nucleotide substitutions also show the most pronounced condition-dependent expression, suggesting a correlation between diversifying selection and allelic differentiation. Divergent alleles may be involved in adaptation to environmental fluctuations in the Southern Ocean. The pennate diatom genus Fragilariopsis is especially successful in the Southern Ocean, with the cold-adapted species F. cylindrus (Fig. 1a) regarded as an indicator species for polar water 8-10. It is frequently found to form large populations in both the bottom layer of sea ice and the wider sea-ice zone, including open waters 9 (Fig. 1b). Sea ice is characterized by temperatures under 0 °C, high salinity and, owing to the semi-enclosed pore system within the ice, low diffusion rates of dissolved gases and exchange of inorganic nutrients 11. However, unlike in ice-free surface waters of the Southern Ocean 12 , dissolved iron is not considered to be limiting to phytoplankton growth within sea ice 13. Most phytoplankton in the Southern Ocean face inclusion into sea ice every winter and are released again in summer when most of the sea ice melts 14 ; certain species such as F. cylindrus have therefore evolved adaptations to cope with this drastic environmental change. Thus, comparative analyses of the genome of the psychrophile F. cylindrus with those of diatoms that evolved in temperate oceans provide an opportunity to obtain insights into how this species has adapted to conditions in Southern Ocean surface waters. We found many loci with highly divergent alleles in the diploid F. cylindrus draft genome sequence. To resolve the divergent alleles from paralogous genes, we independently carried out Sanger and PacBio sequencing and used haplotyped Sanger-finished fosmids to validate the haplotype-resolved genome assemblies (Supplementary Data 1-3). Using complementary approaches, we found that the F. cylindrus genome assembly consists of 15.1 Mb of loci with highly divergent alleles that were assigned to different scaffolds. The remaining 46 Mb of sequence consists of alleles similar enough to be assembled onto the same scaffold (Supplementary Information 2-5). The haplotype assembly size of the genome (61.1 Mb; Extended Data Table 1) was confirmed by quantitative PCR with reverse-transcription (qRT-PCR) (57.9 Mb). The genome completeness according to the Core Eukaryotic Genes Mapping Approach 15 is 95.6% and the nuclear scaffold N50/L50 is 16/1.3 Mb, corresponding to assembly size (Extended Data Table 1). The haplotype-resolved genome contains 21,066 predicted protein-coding genes (Extended Data Table 1) with 6,071 genes (29%) being represented by diverged alleles (Allele sets 1 and 2, Supplementary Data 1). Sequence divergence between alleles was up to 6%, but this was still significantly less (Mann-Whitney, P < 0.001

eLife

Sequestration of Plasmodium falciparum(P. falciparum)-infected erythrocytes to host endothelium t... more Sequestration of Plasmodium falciparum(P. falciparum)-infected erythrocytes to host endothelium through the parasite-derived P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion proteins is central to the development of malaria pathogenesis. PfEMP1 proteins have diversified and expanded to encompass many sequence variants, conferring each parasite a similar array of human endothelial receptor-binding phenotypes. Here, we analyzed RNA-seq profiles of parasites isolated from 32 P. falciparum-infected adult travellers returning to Germany. Patients were categorized into either malaria naive (n = 15) or pre-exposed (n = 17), and into severe (n = 8) or non-severe (n = 24) cases. For differential expression analysis, PfEMP1-encoding var gene transcripts were de novo assembled from RNA-seq data and, in parallel, var-expressed sequence tags were analyzed and used to predict the encoded domain composition of the transcripts. Both approaches showed in concordance that severe malaria...

Communications Biology

Merozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria ... more Merozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria parasite Plasmodium falciparum. Proteins involved with RBC binding and invasion are secreted from dual-club shaped organelles at the apical tip of the merozoite called the rhoptries. Here we characterise P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 2 (PfCERLI2), as a rhoptry bulb protein that is essential for merozoite invasion. Phylogenetic analyses show that cerli2 arose through an ancestral gene duplication of cerli1. We show that PfCERLI2 is essential for blood-stage growth and localises to the cytosolic face of the rhoptry bulb. Inducible knockdown of PfCERLI2 led to a proportion of merozoites failing to invade and was associated with elongation of the rhoptry organelle during merozoite development and inhibition of rhoptry antigen processing. These findings identify PfCERLI2 as a protein that has key roles in rhoptry biology during merozoite invasion.

Abstract. The malacological collections of the German Oceanographic Museum (GOM) in Stralsund and... more Abstract. The malacological collections of the German Oceanographic Museum (GOM) in Stralsund and the Zoological Museum of the University Rostock (ZSRO) keep Cephalopod specimens from all over the world. The inventory and taxonomic revision presented in this study provides an overview of the cephalopod samples present in both collections. The total of 252 specimen records (GOM: 193, ZSRO: 59) represent 51 different species, mainly from northern Atlantic, Mediterranean and western Pacific locations. Special reference is made to species collected from the North Sea. Kurzfassung. In den wissenschaftlichen Mollusken-Sammlungen des Deutschen Meeresmuseums (DMM) in Stralsund und der Zoologischen Sammlung Rostock (ZSRO) werden Cephalopoden-Exemplare aus allen Teilen des Weltmeeres aufbewahrt. Die vorliegende Inventur und taxonomische Revision gibt einen Überblick über das vorhandene Sammlungsmaterial. Unter insgesamt 252

mSphere

Malaria parasites live and multiply inside cells. To facilitate their extremely fast intracellula... more Malaria parasites live and multiply inside cells. To facilitate their extremely fast intracellular proliferation, they hijack and transform their host cells.

ABSTRACTFor its replication within red blood cells, the malaria parasite is highly dependent on c... more ABSTRACTFor its replication within red blood cells, the malaria parasite is highly dependent on correctly regulated lipid metabolism. Enzymes involved in lipid metabolic processes are therefore potential drug targets. We here provide a functional analysis of the 20 putative phospholipases that are expressed by asexual blood stages of Plasmodium falciparum. We reveal a high level of redundancy among members of this group, but using conditional mislocalization and gene disruption techniques we show that the phosphoinositide-specific phospholipase C (PF3D7_1013500) has a previously unrecognized essential role in intracellular parasite maturation. In addition, we demonstrate that the patatin-like phospholipase PF3D7_1358000 localizes to the mitochondrion. Parasites lacking this enzyme display a severe growth phenotype and defects in mitochondrial morphogenesis and function leading to hypersensitivity towards proguanil and inhibitors of the mitochondrial electron transport chain includin...

The Southern Ocean houses a diverse and productive community of organisms 1,2. Unicellular eukary... more The Southern Ocean houses a diverse and productive community of organisms 1,2. Unicellular eukaryotic diatoms are the main primary producers in this environment, where photosynthesis is limited by low concentrations of dissolved iron and large seasonal fluctuations in light, temperature and the extent of sea ice 3-7. How diatoms have adapted to this extreme environment is largely unknown. Here we present insights into the genome evolution of a cold-adapted diatom from the Southern Ocean, Fragilariopsis cylindrus 8,9 , based on a comparison with temperate diatoms. We find that approximately 24.7 per cent of the diploid F. cylindrus genome consists of genetic loci with alleles that are highly divergent (15.1 megabases of the total genome size of 61.1 megabases). These divergent alleles were differentially expressed across environmental conditions, including darkness, low iron, freezing, elevated temperature and increased CO 2. Alleles with the largest ratio of non-synonymous to synonymous nucleotide substitutions also show the most pronounced condition-dependent expression, suggesting a correlation between diversifying selection and allelic differentiation. Divergent alleles may be involved in adaptation to environmental fluctuations in the Southern Ocean. The pennate diatom genus Fragilariopsis is especially successful in the Southern Ocean, with the cold-adapted species F. cylindrus (Fig. 1a) regarded as an indicator species for polar water 8-10. It is frequently found to form large populations in both the bottom layer of sea ice and the wider sea-ice zone, including open waters 9 (Fig. 1b). Sea ice is characterized by temperatures under 0 °C, high salinity and, owing to the semi-enclosed pore system within the ice, low diffusion rates of dissolved gases and exchange of inorganic nutrients 11. However, unlike in ice-free surface waters of the Southern Ocean 12 , dissolved iron is not considered to be limiting to phytoplankton growth within sea ice 13. Most phytoplankton in the Southern Ocean face inclusion into sea ice every winter and are released again in summer when most of the sea ice melts 14 ; certain species such as F. cylindrus have therefore evolved adaptations to cope with this drastic environmental change. Thus, comparative analyses of the genome of the psychrophile F. cylindrus with those of diatoms that evolved in temperate oceans provide an opportunity to obtain insights into how this species has adapted to conditions in Southern Ocean surface waters. We found many loci with highly divergent alleles in the diploid F. cylindrus draft genome sequence. To resolve the divergent alleles from paralogous genes, we independently carried out Sanger and PacBio sequencing and used haplotyped Sanger-finished fosmids to validate the haplotype-resolved genome assemblies (Supplementary Data 1-3). Using complementary approaches, we found that the F. cylindrus genome assembly consists of 15.1 Mb of loci with highly divergent alleles that were assigned to different scaffolds. The remaining 46 Mb of sequence consists of alleles similar enough to be assembled onto the same scaffold (Supplementary Information 2-5). The haplotype assembly size of the genome (61.1 Mb; Extended Data Table 1) was confirmed by quantitative PCR with reverse-transcription (qRT-PCR) (57.9 Mb). The genome completeness according to the Core Eukaryotic Genes Mapping Approach 15 is 95.6% and the nuclear scaffold N50/L50 is 16/1.3 Mb, corresponding to assembly size (Extended Data Table 1). The haplotype-resolved genome contains 21,066 predicted protein-coding genes (Extended Data Table 1) with 6,071 genes (29%) being represented by diverged alleles (Allele sets 1 and 2, Supplementary Data 1). Sequence divergence between alleles was up to 6%, but this was still significantly less (Mann-Whitney, P < 0.001

eLife

Sequestration of Plasmodium falciparum(P. falciparum)-infected erythrocytes to host endothelium t... more Sequestration of Plasmodium falciparum(P. falciparum)-infected erythrocytes to host endothelium through the parasite-derived P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion proteins is central to the development of malaria pathogenesis. PfEMP1 proteins have diversified and expanded to encompass many sequence variants, conferring each parasite a similar array of human endothelial receptor-binding phenotypes. Here, we analyzed RNA-seq profiles of parasites isolated from 32 P. falciparum-infected adult travellers returning to Germany. Patients were categorized into either malaria naive (n = 15) or pre-exposed (n = 17), and into severe (n = 8) or non-severe (n = 24) cases. For differential expression analysis, PfEMP1-encoding var gene transcripts were de novo assembled from RNA-seq data and, in parallel, var-expressed sequence tags were analyzed and used to predict the encoded domain composition of the transcripts. Both approaches showed in concordance that severe malaria...

ABSTRACTFor its replication within red blood cells, the malaria parasite is highly dependent on c... more ABSTRACTFor its replication within red blood cells, the malaria parasite is highly dependent on correctly regulated lipid metabolism. Enzymes involved in lipid metabolic processes are therefore potential drug targets. We here provide a functional analysis of the 20 putative phospholipases that are expressed by asexual blood stages of Plasmodium falciparum. We reveal a high level of redundancy among members of this group, but using conditional mislocalization and gene disruption techniques we show that the phosphoinositide-specific phospholipase C (PF3D7_1013500) has a previously unrecognized essential role in intracellular parasite maturation. In addition, we demonstrate that the patatin-like phospholipase PF3D7_1358000 localizes to the mitochondrion. Parasites lacking this enzyme display a severe growth phenotype and defects in mitochondrial morphogenesis and function leading to hypersensitivity towards proguanil and inhibitors of the mitochondrial electron transport chain includin...

ABSTRACTDuring the symptomatic human blood phase, malaria parasites replicate within red blood ce... more ABSTRACTDuring the symptomatic human blood phase, malaria parasites replicate within red blood cells. Parasite proliferation relies on the uptake of nutrients, such as amino acids, from the host cell and the blood plasma, requiring transport across multiple membranes. Amino acids are delivered to the parasite through the parasite surrounding vacuolar compartment by specialized nutrient-permeable channels of the erythrocyte membrane and the parasitophorous vacuole membrane (PVM). However, further transport of amino acid across the parasite plasma membrane (PPM) is currently not well characterized. In this study, we focused on a family of Apicomplexan amino acid transporters (ApiATs) that comprises five members in Plasmodium falciparum. First, we localized four of the PfApiATs at the PPM using endogenous GFP-tagging. Next, we applied reverse genetic approaches to probe into their essentiality during asexual replication and gametocytogenesis. Upon inducible knockdown and targeted gene ...

Cellular Microbiology

The inner membrane complex (IMC) is a defining feature of apicomplexan parasites, which confers s... more The inner membrane complex (IMC) is a defining feature of apicomplexan parasites, which confers stability and shape to the cell, functions as a scaffolding compartment during the formation of daughter cells and plays an important role in motility and invasion during different life cycle stages of these single-celled organisms. To explore the IMC proteome of the malaria parasite Plasmodium falciparum we applied a proximity-dependent biotin identification (BioID)-based proteomics approach, using the established IMC marker protein Photosensitized INA-Labelled protein 1 (PhIL1) as bait in asexual blood-stage parasites. Subsequent mass spectrometry-based peptide identification revealed enrichment of 12 known IMC proteins and several uncharacterized candidate proteins. We validated nine of these previously uncharacterized proteins by endogenous GFP-tagging. Six of these represent new IMC proteins, while three proteins have a distinct apical localization that most likely represents structures described as apical annuli in Toxoplasma gondii. Additionally, various Kelch13 interacting candidates were identified, suggesting an association of the Kelch13 compartment and the IMC in schizont and merozoite stages. This work extends the number of validated IMC proteins in the malaria parasite and reveals for the first time the existence of apical annuli proteins in P. falciparum. Additionally, it provides evidence for a spatial association between the Kelch13 compartment and the IMC in late blood-stage parasites. 1 | INTRODUCTION Plasmodium sp. are members of the phylogenetic clade Alveolata that comprises a diverse group of unicellular eukaryotes including wellestablished phylogenetic groups such as Ciliates, Dinoflagellates and Apicomplexa (Cavalier-Smith, 1993). A defining feature of the Alveolata is a double-membrane system underlying the plasma membrane that is termed "alveoli" in ciliates and dinoflagellates

ABSTRACTMerozoite invasion of host red blood cells (RBCs) is essential for survival of the human ... more ABSTRACTMerozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria parasite Plasmodium falciparum. Proteins involved with RBC binding and invasion are secreted from dual-club shaped organelles at the apical tip of the merozoite called the rhoptries. Here we characterise P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 2 (PfCERLI2), as a rhoptry bulb protein that is essential for merozoite invasion. Phylogenetic analyses show that cerli2 arose through an ancestral gene duplication of cerli1, a related cytosolically exposed rhoptry bulb protein. We show that PfCERLI2 is essential for blood-stage growth and localises to the cytosolic face of the rhoptry bulb. Inducible knockdown of PfCERLI2 led to an inhibition of merozoite invasion after tight junction formation. PfCERLI2 knockdown was associated with inhibition of rhoptry antigen processing and a significant elongation of the rhoptries, suggesting that the inability of mero...

Cell Reports

Highlights d Crystal structure of the malaria parasite lipocalin d Comparative analysis of lipoca... more Highlights d Crystal structure of the malaria parasite lipocalin d Comparative analysis of lipocalin superfamily members in alveolate genomes d Localization of PfLipocalin to the parasitophorous vacuole and food vacuole d Reverse genetics reveal PfLipocalin function in oxidative damage control

Nature Ecology & Evolution

The Microbiomes of Humans, Animals, Plants, and the Environment, 2022

Communications Biology

Merozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria ... more Merozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria parasite Plasmodium falciparum. Proteins involved with RBC binding and invasion are secreted from dual-club shaped organelles at the apical tip of the merozoite called the rhoptries. Here we characterise P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 2 (PfCERLI2), as a rhoptry bulb protein that is essential for merozoite invasion. Phylogenetic analyses show that cerli2 arose through an ancestral gene duplication of cerli1. We show that PfCERLI2 is essential for blood-stage growth and localises to the cytosolic face of the rhoptry bulb. Inducible knockdown of PfCERLI2 led to a proportion of merozoites failing to invade and was associated with elongation of the rhoptry organelle during merozoite development and inhibition of rhoptry antigen processing. These findings identify PfCERLI2 as a protein that has key roles in rhoptry biology during merozoite invasion.

Abstract. The malacological collections of the German Oceanographic Museum (GOM) in Stralsund and... more Abstract. The malacological collections of the German Oceanographic Museum (GOM) in Stralsund and the Zoological Museum of the University Rostock (ZSRO) keep Cephalopod specimens from all over the world. The inventory and taxonomic revision presented in this study provides an overview of the cephalopod samples present in both collections. The total of 252 specimen records (GOM: 193, ZSRO: 59) represent 51 different species, mainly from northern Atlantic, Mediterranean and western Pacific locations. Special reference is made to species collected from the North Sea. Kurzfassung. In den wissenschaftlichen Mollusken-Sammlungen des Deutschen Meeresmuseums (DMM) in Stralsund und der Zoologischen Sammlung Rostock (ZSRO) werden Cephalopoden-Exemplare aus allen Teilen des Weltmeeres aufbewahrt. Die vorliegende Inventur und taxonomische Revision gibt einen Überblick über das vorhandene Sammlungsmaterial. Unter insgesamt 252

Membrane transport proteins perform crucial roles in cell physiology. The obligate intracellular ... more Membrane transport proteins perform crucial roles in cell physiology. The obligate intracellular parasite Plasmodium falciparum, an agent of human malaria, relies on membrane transport proteins for the uptake of nutrients from the host, disposal of metabolic waste, exchange of metabolites between organelles and generation and maintenance of transmembrane electrochemical gradients for its growth and replication within human erythrocytes. Despite their importance for Plasmodium cellular physiology, the functional roles of a number of membrane transport proteins remain unclear, which is particularly true for orphan membrane transporters that have no or limited sequence homology to transporter proteins in other evolutionary lineages. Therefore, in the current study, we applied endogenous tagging, targeted gene disruption, conditional knockdown and knockout approaches to investigate the subcellular localization and essentiality of six membrane transporters during intraerythrocytic develo...

mSphere

Malaria parasites live and multiply inside cells. To facilitate their extremely fast intracellula... more Malaria parasites live and multiply inside cells. To facilitate their extremely fast intracellular proliferation, they hijack and transform their host cells.

The Southern Ocean houses a diverse and productive community of organisms 1,2. Unicellular eukary... more The Southern Ocean houses a diverse and productive community of organisms 1,2. Unicellular eukaryotic diatoms are the main primary producers in this environment, where photosynthesis is limited by low concentrations of dissolved iron and large seasonal fluctuations in light, temperature and the extent of sea ice 3-7. How diatoms have adapted to this extreme environment is largely unknown. Here we present insights into the genome evolution of a cold-adapted diatom from the Southern Ocean, Fragilariopsis cylindrus 8,9 , based on a comparison with temperate diatoms. We find that approximately 24.7 per cent of the diploid F. cylindrus genome consists of genetic loci with alleles that are highly divergent (15.1 megabases of the total genome size of 61.1 megabases). These divergent alleles were differentially expressed across environmental conditions, including darkness, low iron, freezing, elevated temperature and increased CO 2. Alleles with the largest ratio of non-synonymous to synonymous nucleotide substitutions also show the most pronounced condition-dependent expression, suggesting a correlation between diversifying selection and allelic differentiation. Divergent alleles may be involved in adaptation to environmental fluctuations in the Southern Ocean. The pennate diatom genus Fragilariopsis is especially successful in the Southern Ocean, with the cold-adapted species F. cylindrus (Fig. 1a) regarded as an indicator species for polar water 8-10. It is frequently found to form large populations in both the bottom layer of sea ice and the wider sea-ice zone, including open waters 9 (Fig. 1b). Sea ice is characterized by temperatures under 0 °C, high salinity and, owing to the semi-enclosed pore system within the ice, low diffusion rates of dissolved gases and exchange of inorganic nutrients 11. However, unlike in ice-free surface waters of the Southern Ocean 12 , dissolved iron is not considered to be limiting to phytoplankton growth within sea ice 13. Most phytoplankton in the Southern Ocean face inclusion into sea ice every winter and are released again in summer when most of the sea ice melts 14 ; certain species such as F. cylindrus have therefore evolved adaptations to cope with this drastic environmental change. Thus, comparative analyses of the genome of the psychrophile F. cylindrus with those of diatoms that evolved in temperate oceans provide an opportunity to obtain insights into how this species has adapted to conditions in Southern Ocean surface waters. We found many loci with highly divergent alleles in the diploid F. cylindrus draft genome sequence. To resolve the divergent alleles from paralogous genes, we independently carried out Sanger and PacBio sequencing and used haplotyped Sanger-finished fosmids to validate the haplotype-resolved genome assemblies (Supplementary Data 1-3). Using complementary approaches, we found that the F. cylindrus genome assembly consists of 15.1 Mb of loci with highly divergent alleles that were assigned to different scaffolds. The remaining 46 Mb of sequence consists of alleles similar enough to be assembled onto the same scaffold (Supplementary Information 2-5). The haplotype assembly size of the genome (61.1 Mb; Extended Data Table 1) was confirmed by quantitative PCR with reverse-transcription (qRT-PCR) (57.9 Mb). The genome completeness according to the Core Eukaryotic Genes Mapping Approach 15 is 95.6% and the nuclear scaffold N50/L50 is 16/1.3 Mb, corresponding to assembly size (Extended Data Table 1). The haplotype-resolved genome contains 21,066 predicted protein-coding genes (Extended Data Table 1) with 6,071 genes (29%) being represented by diverged alleles (Allele sets 1 and 2, Supplementary Data 1). Sequence divergence between alleles was up to 6%, but this was still significantly less (Mann-Whitney, P < 0.001

eLife

Sequestration of Plasmodium falciparum(P. falciparum)-infected erythrocytes to host endothelium t... more Sequestration of Plasmodium falciparum(P. falciparum)-infected erythrocytes to host endothelium through the parasite-derived P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion proteins is central to the development of malaria pathogenesis. PfEMP1 proteins have diversified and expanded to encompass many sequence variants, conferring each parasite a similar array of human endothelial receptor-binding phenotypes. Here, we analyzed RNA-seq profiles of parasites isolated from 32 P. falciparum-infected adult travellers returning to Germany. Patients were categorized into either malaria naive (n = 15) or pre-exposed (n = 17), and into severe (n = 8) or non-severe (n = 24) cases. For differential expression analysis, PfEMP1-encoding var gene transcripts were de novo assembled from RNA-seq data and, in parallel, var-expressed sequence tags were analyzed and used to predict the encoded domain composition of the transcripts. Both approaches showed in concordance that severe malaria...

Communications Biology

Merozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria ... more Merozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria parasite Plasmodium falciparum. Proteins involved with RBC binding and invasion are secreted from dual-club shaped organelles at the apical tip of the merozoite called the rhoptries. Here we characterise P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 2 (PfCERLI2), as a rhoptry bulb protein that is essential for merozoite invasion. Phylogenetic analyses show that cerli2 arose through an ancestral gene duplication of cerli1. We show that PfCERLI2 is essential for blood-stage growth and localises to the cytosolic face of the rhoptry bulb. Inducible knockdown of PfCERLI2 led to a proportion of merozoites failing to invade and was associated with elongation of the rhoptry organelle during merozoite development and inhibition of rhoptry antigen processing. These findings identify PfCERLI2 as a protein that has key roles in rhoptry biology during merozoite invasion.

Abstract. The malacological collections of the German Oceanographic Museum (GOM) in Stralsund and... more Abstract. The malacological collections of the German Oceanographic Museum (GOM) in Stralsund and the Zoological Museum of the University Rostock (ZSRO) keep Cephalopod specimens from all over the world. The inventory and taxonomic revision presented in this study provides an overview of the cephalopod samples present in both collections. The total of 252 specimen records (GOM: 193, ZSRO: 59) represent 51 different species, mainly from northern Atlantic, Mediterranean and western Pacific locations. Special reference is made to species collected from the North Sea. Kurzfassung. In den wissenschaftlichen Mollusken-Sammlungen des Deutschen Meeresmuseums (DMM) in Stralsund und der Zoologischen Sammlung Rostock (ZSRO) werden Cephalopoden-Exemplare aus allen Teilen des Weltmeeres aufbewahrt. Die vorliegende Inventur und taxonomische Revision gibt einen Überblick über das vorhandene Sammlungsmaterial. Unter insgesamt 252

mSphere

Malaria parasites live and multiply inside cells. To facilitate their extremely fast intracellula... more Malaria parasites live and multiply inside cells. To facilitate their extremely fast intracellular proliferation, they hijack and transform their host cells.

ABSTRACTFor its replication within red blood cells, the malaria parasite is highly dependent on c... more ABSTRACTFor its replication within red blood cells, the malaria parasite is highly dependent on correctly regulated lipid metabolism. Enzymes involved in lipid metabolic processes are therefore potential drug targets. We here provide a functional analysis of the 20 putative phospholipases that are expressed by asexual blood stages of Plasmodium falciparum. We reveal a high level of redundancy among members of this group, but using conditional mislocalization and gene disruption techniques we show that the phosphoinositide-specific phospholipase C (PF3D7_1013500) has a previously unrecognized essential role in intracellular parasite maturation. In addition, we demonstrate that the patatin-like phospholipase PF3D7_1358000 localizes to the mitochondrion. Parasites lacking this enzyme display a severe growth phenotype and defects in mitochondrial morphogenesis and function leading to hypersensitivity towards proguanil and inhibitors of the mitochondrial electron transport chain includin...

The Southern Ocean houses a diverse and productive community of organisms 1,2. Unicellular eukary... more The Southern Ocean houses a diverse and productive community of organisms 1,2. Unicellular eukaryotic diatoms are the main primary producers in this environment, where photosynthesis is limited by low concentrations of dissolved iron and large seasonal fluctuations in light, temperature and the extent of sea ice 3-7. How diatoms have adapted to this extreme environment is largely unknown. Here we present insights into the genome evolution of a cold-adapted diatom from the Southern Ocean, Fragilariopsis cylindrus 8,9 , based on a comparison with temperate diatoms. We find that approximately 24.7 per cent of the diploid F. cylindrus genome consists of genetic loci with alleles that are highly divergent (15.1 megabases of the total genome size of 61.1 megabases). These divergent alleles were differentially expressed across environmental conditions, including darkness, low iron, freezing, elevated temperature and increased CO 2. Alleles with the largest ratio of non-synonymous to synonymous nucleotide substitutions also show the most pronounced condition-dependent expression, suggesting a correlation between diversifying selection and allelic differentiation. Divergent alleles may be involved in adaptation to environmental fluctuations in the Southern Ocean. The pennate diatom genus Fragilariopsis is especially successful in the Southern Ocean, with the cold-adapted species F. cylindrus (Fig. 1a) regarded as an indicator species for polar water 8-10. It is frequently found to form large populations in both the bottom layer of sea ice and the wider sea-ice zone, including open waters 9 (Fig. 1b). Sea ice is characterized by temperatures under 0 °C, high salinity and, owing to the semi-enclosed pore system within the ice, low diffusion rates of dissolved gases and exchange of inorganic nutrients 11. However, unlike in ice-free surface waters of the Southern Ocean 12 , dissolved iron is not considered to be limiting to phytoplankton growth within sea ice 13. Most phytoplankton in the Southern Ocean face inclusion into sea ice every winter and are released again in summer when most of the sea ice melts 14 ; certain species such as F. cylindrus have therefore evolved adaptations to cope with this drastic environmental change. Thus, comparative analyses of the genome of the psychrophile F. cylindrus with those of diatoms that evolved in temperate oceans provide an opportunity to obtain insights into how this species has adapted to conditions in Southern Ocean surface waters. We found many loci with highly divergent alleles in the diploid F. cylindrus draft genome sequence. To resolve the divergent alleles from paralogous genes, we independently carried out Sanger and PacBio sequencing and used haplotyped Sanger-finished fosmids to validate the haplotype-resolved genome assemblies (Supplementary Data 1-3). Using complementary approaches, we found that the F. cylindrus genome assembly consists of 15.1 Mb of loci with highly divergent alleles that were assigned to different scaffolds. The remaining 46 Mb of sequence consists of alleles similar enough to be assembled onto the same scaffold (Supplementary Information 2-5). The haplotype assembly size of the genome (61.1 Mb; Extended Data Table 1) was confirmed by quantitative PCR with reverse-transcription (qRT-PCR) (57.9 Mb). The genome completeness according to the Core Eukaryotic Genes Mapping Approach 15 is 95.6% and the nuclear scaffold N50/L50 is 16/1.3 Mb, corresponding to assembly size (Extended Data Table 1). The haplotype-resolved genome contains 21,066 predicted protein-coding genes (Extended Data Table 1) with 6,071 genes (29%) being represented by diverged alleles (Allele sets 1 and 2, Supplementary Data 1). Sequence divergence between alleles was up to 6%, but this was still significantly less (Mann-Whitney, P < 0.001

eLife

Sequestration of Plasmodium falciparum(P. falciparum)-infected erythrocytes to host endothelium t... more Sequestration of Plasmodium falciparum(P. falciparum)-infected erythrocytes to host endothelium through the parasite-derived P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion proteins is central to the development of malaria pathogenesis. PfEMP1 proteins have diversified and expanded to encompass many sequence variants, conferring each parasite a similar array of human endothelial receptor-binding phenotypes. Here, we analyzed RNA-seq profiles of parasites isolated from 32 P. falciparum-infected adult travellers returning to Germany. Patients were categorized into either malaria naive (n = 15) or pre-exposed (n = 17), and into severe (n = 8) or non-severe (n = 24) cases. For differential expression analysis, PfEMP1-encoding var gene transcripts were de novo assembled from RNA-seq data and, in parallel, var-expressed sequence tags were analyzed and used to predict the encoded domain composition of the transcripts. Both approaches showed in concordance that severe malaria...

ABSTRACTFor its replication within red blood cells, the malaria parasite is highly dependent on c... more ABSTRACTFor its replication within red blood cells, the malaria parasite is highly dependent on correctly regulated lipid metabolism. Enzymes involved in lipid metabolic processes are therefore potential drug targets. We here provide a functional analysis of the 20 putative phospholipases that are expressed by asexual blood stages of Plasmodium falciparum. We reveal a high level of redundancy among members of this group, but using conditional mislocalization and gene disruption techniques we show that the phosphoinositide-specific phospholipase C (PF3D7_1013500) has a previously unrecognized essential role in intracellular parasite maturation. In addition, we demonstrate that the patatin-like phospholipase PF3D7_1358000 localizes to the mitochondrion. Parasites lacking this enzyme display a severe growth phenotype and defects in mitochondrial morphogenesis and function leading to hypersensitivity towards proguanil and inhibitors of the mitochondrial electron transport chain includin...

ABSTRACTDuring the symptomatic human blood phase, malaria parasites replicate within red blood ce... more ABSTRACTDuring the symptomatic human blood phase, malaria parasites replicate within red blood cells. Parasite proliferation relies on the uptake of nutrients, such as amino acids, from the host cell and the blood plasma, requiring transport across multiple membranes. Amino acids are delivered to the parasite through the parasite surrounding vacuolar compartment by specialized nutrient-permeable channels of the erythrocyte membrane and the parasitophorous vacuole membrane (PVM). However, further transport of amino acid across the parasite plasma membrane (PPM) is currently not well characterized. In this study, we focused on a family of Apicomplexan amino acid transporters (ApiATs) that comprises five members in Plasmodium falciparum. First, we localized four of the PfApiATs at the PPM using endogenous GFP-tagging. Next, we applied reverse genetic approaches to probe into their essentiality during asexual replication and gametocytogenesis. Upon inducible knockdown and targeted gene ...

Cellular Microbiology

The inner membrane complex (IMC) is a defining feature of apicomplexan parasites, which confers s... more The inner membrane complex (IMC) is a defining feature of apicomplexan parasites, which confers stability and shape to the cell, functions as a scaffolding compartment during the formation of daughter cells and plays an important role in motility and invasion during different life cycle stages of these single-celled organisms. To explore the IMC proteome of the malaria parasite Plasmodium falciparum we applied a proximity-dependent biotin identification (BioID)-based proteomics approach, using the established IMC marker protein Photosensitized INA-Labelled protein 1 (PhIL1) as bait in asexual blood-stage parasites. Subsequent mass spectrometry-based peptide identification revealed enrichment of 12 known IMC proteins and several uncharacterized candidate proteins. We validated nine of these previously uncharacterized proteins by endogenous GFP-tagging. Six of these represent new IMC proteins, while three proteins have a distinct apical localization that most likely represents structures described as apical annuli in Toxoplasma gondii. Additionally, various Kelch13 interacting candidates were identified, suggesting an association of the Kelch13 compartment and the IMC in schizont and merozoite stages. This work extends the number of validated IMC proteins in the malaria parasite and reveals for the first time the existence of apical annuli proteins in P. falciparum. Additionally, it provides evidence for a spatial association between the Kelch13 compartment and the IMC in late blood-stage parasites. 1 | INTRODUCTION Plasmodium sp. are members of the phylogenetic clade Alveolata that comprises a diverse group of unicellular eukaryotes including wellestablished phylogenetic groups such as Ciliates, Dinoflagellates and Apicomplexa (Cavalier-Smith, 1993). A defining feature of the Alveolata is a double-membrane system underlying the plasma membrane that is termed "alveoli" in ciliates and dinoflagellates

ABSTRACTMerozoite invasion of host red blood cells (RBCs) is essential for survival of the human ... more ABSTRACTMerozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria parasite Plasmodium falciparum. Proteins involved with RBC binding and invasion are secreted from dual-club shaped organelles at the apical tip of the merozoite called the rhoptries. Here we characterise P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 2 (PfCERLI2), as a rhoptry bulb protein that is essential for merozoite invasion. Phylogenetic analyses show that cerli2 arose through an ancestral gene duplication of cerli1, a related cytosolically exposed rhoptry bulb protein. We show that PfCERLI2 is essential for blood-stage growth and localises to the cytosolic face of the rhoptry bulb. Inducible knockdown of PfCERLI2 led to an inhibition of merozoite invasion after tight junction formation. PfCERLI2 knockdown was associated with inhibition of rhoptry antigen processing and a significant elongation of the rhoptries, suggesting that the inability of mero...

Cell Reports

Highlights d Crystal structure of the malaria parasite lipocalin d Comparative analysis of lipoca... more Highlights d Crystal structure of the malaria parasite lipocalin d Comparative analysis of lipocalin superfamily members in alveolate genomes d Localization of PfLipocalin to the parasitophorous vacuole and food vacuole d Reverse genetics reveal PfLipocalin function in oxidative damage control