International journal for parasitology最新文献

{"title":"Chromosome-contiguous genome for the Haecon-5 strain of Haemonchus contortus reveals marked genetic variability and enables the discovery of essential gene candidates","authors":"Yuanting Zheng ,&nbsp;Neil D. Young ,&nbsp;Tulio L. Campos ,&nbsp;Pasi K. Korhonen ,&nbsp;Tao Wang ,&nbsp;Sunita B. Sumanam ,&nbsp;Aya C. Taki ,&nbsp;Joseph J. Byrne ,&nbsp;Bill C.H. Chang ,&nbsp;Jiangning Song ,&nbsp;Robin B. Gasser","doi":"10.1016/j.ijpara.2024.08.003","DOIUrl":"10.1016/j.ijpara.2024.08.003","url":null,"abstract":"<div><div>Millions of livestock animals worldwide are infected with the haematophagous barber’s pole worm, <em>Haemonchus contortus</em>, the aetiological agent of haemonchosis. Despite the major significance of this parasite worldwide and its widespread resistance to current treatments, the lack of a high-quality genome for the well-defined strain of this parasite from Australia, called Haecon-5, has constrained research in a number of areas including host-parasite interactions, drug discovery and population genetics. To enable research in these areas, we report here a chromosome-contiguous genome (∼280 Mb) for Haecon-5 with high-quality models for 19,234 protein-coding genes. Comparative genomic analyses show significant genomic similarity (synteny) with a UK strain of <em>H. contortus</em>, called MHco3(ISE).N1 (abbreviated as “ISE”), but we also discover marked differences in genomic structure/gene arrangements, distribution of nucleotide variability (single nucleotide polymorphisms (SNPs) and indels) and orthology between Haecon-5 and ISE. We used the genome and extensive transcriptomic resources for Haecon-5 to predict a subset of essential single-copy genes employing a “cross-species” machine learning (ML) approach using a range of features from nucleotide/protein sequences, protein orthology, subcellular localisation, single-cell RNA-seq and/or histone methylation data available for the model organisms <em>Caenorhabditis elegans</em> and <em>Drosophila melanogaster</em>. From a set of 1,464 conserved single copy genes, transcribed in key life-cycle stages of <em>H. contortus</em>, we identified 232 genes whose homologs have critical functions in <em>C. elegans</em> and/or <em>D. melanogaster</em>, and prioritised 10 of them for further characterisation; nine of the 10 genes likely play roles in neurophysiological processes, germline, hypodermis and/or respiration, and one is an unknown (orphan) gene for which no detailed functional information exists. Future studies of these genes/gene products are warranted to elucidate their roles in parasite biology, host-parasite interplay and/or disease. Clearly, the present Haecon-5 reference genome and associated resources now underpin a broad range of fundamental investigations of <em>H. contortus</em> and could assist in accelerating the discovery of novel intervention targets and drug candidates to combat haemonchosis.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 13","pages":"Pages 705-715"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142017329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Micro RNA profiles of host extracellular vesicles are modulated by Ascaris suum infection but parasite extracellular vesicle miRNAs are systemically undetectable using in-depth miRNA sequencing","authors":"Bradley Whitehead ,&nbsp;Litten Sørensen Rossen ,&nbsp;Mads Zippor ,&nbsp;Anders T. Boysen ,&nbsp;Vineesh Indira Chandran ,&nbsp;Per Skallerup ,&nbsp;Stig M. Thamsborg ,&nbsp;Peter Nejsum","doi":"10.1016/j.ijpara.2024.08.001","DOIUrl":"10.1016/j.ijpara.2024.08.001","url":null,"abstract":"<div><div>The intestinal helminth <em>Ascaris lumbricoides</em> infects over 800 million people. Infections are often chronic and immunity is not sterilizing due to host-immune modulation, therefore reinfection is common after antihelmintic treatment. We have previously demonstrated a role for <em>Ascaris</em> spp. extracellular vesicles (EVs) in host immune modulation but whether EVs are recognized by the adaptive immune system and are present systemically in the host remains unknown. Therefore, we employed a well-established trickle infection model in pigs to mimic natural <em>Ascaris</em> infection in humans. EVs were isolated from adult <em>Ascaris suum</em> followed by immunoblotting of EV and EV-depleted secretory fractions using plasma from infected and uninfected pigs. Next, EVs were isolated from pig plasma at day 56 post first infection and subjected to deep small RNAseq analysis. RNAs were aligned to <em>A. suum</em> and <em>Sus scrofa</em> miRNA complements to detect <em>A. suum</em> EVs and elucidate the host EV micro RNA (miRNA) response to infection, respectively. Infection generates robust antibody responses against <em>A. suum</em> EVs that is distinct from EV-depleted fractions. However, <em>A. suum</em> miRNAs were not detectable in EVs from the peripheral blood. Notably, host plasma-derived EV miRNA profiles showed significant changes between infected and uninfected pigs, indicating that <em>Ascaris</em> infection drives systemic changes in host EV composition.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 13","pages":"Pages 691-696"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141906580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DNA N-glycosylases Ogg1 and EndoIII as components of base excision repair in Plasmodium falciparum organelles","authors":"Anupama Tiwari ,&nbsp;Neetu Verma ,&nbsp;Himadri Shukla ,&nbsp;Shivani Mishra ,&nbsp;Kit Kennedy ,&nbsp;Tribeni Chatterjee ,&nbsp;Jitendra Kuldeep ,&nbsp;Shahid Parwez ,&nbsp;MI Siddiqi ,&nbsp;Stuart A. Ralph ,&nbsp;Satish Mishra ,&nbsp;Saman Habib","doi":"10.1016/j.ijpara.2024.06.005","DOIUrl":"10.1016/j.ijpara.2024.06.005","url":null,"abstract":"<div><div>The integrity of genomes of the two crucial organelles of the malaria parasite — an apicoplast and mitochondrion in each cell − must be maintained by DNA repair mediated by proteins targeted to these compartments. We explored the localisation and function of <em>Plasmodium falciparum</em><span> base excision repair (BER) DNA N-glycosylase homologs </span><em>Pf</em>EndoIII and <em>Pf</em>Ogg1. These N-glycosylases would putatively recognise DNA lesions prior to the action of apurinic/apyrimidinic (AP)-endonucleases. Both Ape1 and Apn1 endonucleases have earlier been shown to function solely in the parasite mitochondrion. Immunofluorescence localisation showed that <em>Pf</em>EndoIII was exclusively mitochondrial. <em>Pf</em>Ogg1 was not seen clearly in mitochondria when expressed as a <em>Pf</em>Ogg1_leader-GFP fusion, although chromatin immunoprecipitation assays showed that it could interact with both mitochondrial and apicoplast DNA. Recombinant <em>Pf</em>EndoIII functioned as a DNA N-glycosylase as well as an AP-lyase on thymine glycol (Tg) lesions. We further studied the importance of Ogg1 in the malaria life cycle using reverse genetic approaches in <em>Plasmodium berghei</em>. Targeted disruption of <em>Pb</em>Ogg1 resulted in loss of 8-oxo-G specific DNA glycosylase/lyase activity. <em>Pb</em>Ogg1 knockout did not affect blood, mosquito or liver stage development but caused reduced blood stage infection after inoculation of sporozoites in mice. A significant reduction in erythrocyte infectivity by <em>Pb</em>Ogg1 knockout hepatic merozoites was also observed, thus showing that <em>Pb</em>Ogg1 ensures smooth transition from liver to blood stage infection. Our results strengthen the view that the <em>Plasmodium</em><span> mitochondrial genome is an important site for DNA repair by the BER pathway.</span></div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 13","pages":"Pages 675-689"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141534413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The concentration McMaster method for diagnosis of patent Ascaris and Trichuris infections in humans","authors":"Sozan Kader ,&nbsp;Christine E. Helmersen ,&nbsp;Stig M. Thamsborg ,&nbsp;Lise T. Erikstrup ,&nbsp;Peter Nejsum","doi":"10.1016/j.ijpara.2024.08.004","DOIUrl":"10.1016/j.ijpara.2024.08.004","url":null,"abstract":"<div><div>In tropical and subtropical regions, soil-transmitted helminth (STH) infections such as <em>Ascaris lumbricoides</em>, <em>Trichuris trichiura</em>, and hookworms have a significant impact on public health. Globally, <em>A. lumbricoides</em> infects approximately 0.8 billion people, while <em>T. trichiura</em> infects around 500 million. This study involved a comparison of three diagnostic methods, Kato-Katz and two flotation methods (concentration McMaster, and simple McMaster), for the detection of <em>Ascaris</em> and <em>Trichuris</em> in human faeces. We conducted a comparison of the number of eggs in faeces (or faecal egg counts (FECs)) obtained with these methods using freshly collected samples that were positive for <em>T. trichiura</em> and spiked with a known quantity of <em>Ascaris</em> sp. eggs. Additionally, for the concentration McMaster method we assessed FECs after storing the samples at 5 °C for up to 21 days. The concentration McMaster method demonstrated superiority over the simple McMaster method in terms of higher detection levels for both helminths, while the Kato-Katz method yielded FEC values very close to the ’true’ spiking values. Importantly, the concentration McMaster method was considerably easier to read compared with the Kato-Katz method, and it allowed for sample storage at 5 °C for up to 14 days without affecting FEC results. Consequently, we conclude that the concentration McMaster method is an effective and user-friendly alternative for diagnosis of <em>Ascaris</em> and <em>Trichuris</em> infections in humans. Furthermore, it offers the advantage of sample storage before analysis, enhancing flexibility in the workflow.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 13","pages":"Pages 717-722"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142107085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potential effects of host competence and schooling behavior on parasite transmission in a host-pathogen system: a test of the dilution effect","authors":"Shun Zhou ,&nbsp;Xiao Jin ,&nbsp;Ming Duan ,&nbsp;Hong Zou ,&nbsp;Ming Li ,&nbsp;David J. Marcogliese ,&nbsp;Guitang Wang ,&nbsp;Wenxiang Li","doi":"10.1016/j.ijpara.2024.08.002","DOIUrl":"10.1016/j.ijpara.2024.08.002","url":null,"abstract":"<div><div>High species diversity in a community may reduce the risk of infectious disease, termed the dilution effect. However, the generality of the dilution effect in different disease systems remains controversial as both host competence and behaviors of hosts may play roles in dilution or amplification of disease. Using the goldfish (<em>Carassius auratus</em>)-monogenean ectoparasite (<em>Gyrodactylus kobayashii</em>) system, effects of host competence and schooling behavior on parasite transmission were investigated while holding focal host density constant. Following competency tests of 12 fish species as potential hosts for the parasite, infection by <em>G. kobayashii</em> was determined on fins of goldfish mixed with each of three different species based on their level of host competence, including Prussian carp, <em>Carassius gibelio</em> (low competence), grass carp, <em>Ctenopharyngodon idellus</em> (non-competent), swordtail, <em>Xiphophorus helleri</em> (non-competent), and the four species combined. Compared with mean abundance (85.8 ± 25.1) on goldfish in the control group, the mean abundance on goldfish decreased significantly when paired with 10 Prussian carp (30.0 ± 16.5), but did not differ significantly when paired with 10 swordtail (70.0 ± 22.2), 10 grass carp (116.1 ± 33.2), or the multi-species of three Prussian carp, four grass carp and three swordtail (75.9 ± 30.8) during the 11-day experiment. The parasite was also found on the Prussian carp in the Prussian carp group and the multi-species group at a mean abundance of 7.1 and 10.9, respectively. Video recording showed that the school of goldfish mixed well with the Prussian carp, while they maintained separation from the grass carp and swordtail when mixed together. The distance between goldfish increased, and swimming speed and contact time decreased with the additional of other fish species for all groups. The results suggested that the presence of a low-competence host in sufficient numbers was a necessary condition for a dilution effect due to encounter reduction, and the dilution effect may also be enhanced by changes in schooling behavior of goldfish in the presence of low competence hosts. However, the presence of non-competent hosts did not result in any dilution effect owing to the specialist nature of the parasites and the lack of mixing with schools of goldfish.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 13","pages":"Pages 697-703"},"PeriodicalIF":3.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141987900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acanthamoeba castellanii trophozoites need oxygen for normal functioning and lipids are their preferred substrate, offering new possibilities for treatment.","authors":"Maarten J Sarink, Anna Z Mykytyn, Aïsha Jedidi, Martin Houweling, Jos F Brouwers, George Ruijter, Annelies Verbon, Jaap J van Hellemond, Aloysius G M Tielens","doi":"10.1016/j.ijpara.2024.10.004","DOIUrl":"10.1016/j.ijpara.2024.10.004","url":null,"abstract":"<p><p>Acanthamoebae, pathogenic free-living amoebae, can cause Granulomatous Amoebic Encephalitis (GAE) and keratitis, and for both types of infection, no adequate treatment options are available. As the metabolism of pathogens is an attractive treatment target, we set out to examine the energy metabolism of Acanthamoeba castellanii and studied the aerobic and anaerobic capacities of the trophozoites. Under anaerobic conditions, or in the presence of inhibitors of the electron-transport chain, A. castellanii trophozoites became rounded, moved sluggishly and stopped multiplying. This demonstrates that oxygen and the respiratory chain are essential for movement and replication. Furthermore, the simultaneous activities of both terminal oxidases, cytochrome c oxidase and the plant-like alternative oxidase, are essential for normal functioning and replication. The inhibition of normal function caused by the inactivity of the respiratory chain was reversible. Once respiration was made possible again, the rounded, rather inactive amoebae formed acanthopodia within 4 h and resumed moving, feeding and multiplying. Experiments with radiolabelled nutrients revealed a preference for lipids over glucose and amino acids as food. Subsequent experiments showed that adding lipids to a standard culture medium of trophozoites strongly increased the growth rate. Acanthamoeba castellanii trophozoites have a strictly aerobic energy metabolism and β-oxidation of fatty acids, the Krebs cycle, and an aerobic electron-transport chain coupled to the ATP synthase, producing most of the used ATP. The preference for lipids can be exploited, as we show that three known inhibitors of lipid oxidation strongly inhibited the growth of A. castellanii. In particular, thioridazine and perhexiline showed potent effects in low micromolar concentrations. Therefore, this study revealed a new drug target with possibly new options to treat Acanthamoeba infections.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142568484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Different life strategies of closely related louse species in sympatry: specialist and \"generalist\" lineages of Polyplax serrata.","authors":"Jana Martinů, Jan Štefka, Kateřina Vránková, Václav Hypša","doi":"10.1016/j.ijpara.2024.10.003","DOIUrl":"10.1016/j.ijpara.2024.10.003","url":null,"abstract":"<p><p>The origin and significance of host specificity are intriguing questions in parasitology. In the case of single-host versus multiple-host parasites, this topic integrates with the concept of the specialist/generalist trade-off. We use the model of sucking lice Polyplax serrata and rodent hosts Apodemus, to address these concepts. Polyplax serrata was shown to form a complex genetic structure, with a strictly specific S lineage living on Apodemus flavicollis, and a less specific N lineage on A. flavicollis and Apodemus sylvaticus. Moreover, the S lineage formed two mitochondrial clades with geographically exclusive distributions and a narrow hybrid zone, providing an opportunity to test the hypothesis that hybrids suffer a decrease in fitness. We sampled 451 individual lice from two host species at 103 localities. We used prevalences and intensities as proxies of fitness, which the parasites realize on their host. The S lineage, strictly specific to Apodemus flavicollis, reached significantly higher prevalences and intensities on its host compared with the N lineage. Conversely, the N lineage occurred with high prevalence and intensity on A. sylvaticus but tended to use also A. flavicollis when the louse populations became too dense. We discuss possible mechanisms behind this difference (particularly interspecific competition as a typical phenomenon in the specialist/generalist systems). We conclude that a parasite's \"choice\", not accessibility of the host or interspecific competition, is the main factor affecting the louse prevalences. We suggest that historical differences in geographic distribution of both lice and mice may provide a possible explanation for the observed life strategy differences. In contrast to the convincing picture in S and N lineage prevalences, we did not detect an expected drop in fitness in hybrids. We consider instability of the hybrid zone, or decline in abundance of the respective hosts, as possible explanations for this result.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142464482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Northward migration past the nearctic biogeographical divide; neotropical Gyrodactylus spp. infecting Astyanax have crossed the Trans-Mexican Volcanic Belt.","authors":"Daniel Augusto Pozos-Carré, Carlos Daniel Pinacho-Pinacho, Miguel Calixto-Rojas, Juan Manuel Caspeta-Mandujano, Juan Pablo Ramírez-Herrejón, Adriana García-Vásquez, Juan José Barrios-Gutiérrez, Ismael Guzmán-Valdivieso, Miguel Rubio-Godoy","doi":"10.1016/j.ijpara.2024.10.001","DOIUrl":"10.1016/j.ijpara.2024.10.001","url":null,"abstract":"<p><p>The neotropical fish genus Astyanax (Characidae) and its associated helminths migrated northward from South America following the Great American Biotic Interchange (GABI): ca. 150 Astyanax spp. are found throughout South and Central America, up to the Mexico-USA border. Most characids are distributed south of the Trans-Mexican Volcanic Belt (TMVB), which bisects the country and represents a major transition zone between the neotropical and nearctic realms. Here, we characterize parasites of the monogenean genus Gyrodactylus infecting Astyanax spp. in Mexico: Astyanax aeneus south of the TMBV, Astyanax mexicanus north of it. Based on morphological, phylogenetic (internal transcribed spacer (ITS) and cytochrome oxidase subunit II (cox 2)) and statistical analyses of morphometric data, we confirmed the validity of Gyrodactylus pakan and Gyrodactylus teken, and erected two new species, Gyrodactylus aphaa n. sp. and Gyrodactylus ricardoi n. sp. These four gyrodactylids are part of a complex of morphologically cryptic species, which are phylogenetically closely related to each other, and sister species to Gyrodactylus carolinae and Gyrodactylus heteracanthus, parasites of characins in Brazil. Four gyrodactylid lineages (G. pakan, G. ricardoi n. sp., G. teken, Gyrodactylus sp. A) are distributed north of the TMVB; G. pakan is also widely distributed south of the TMVB, together with G. aphaa n. sp. Based on the ITS phylogeny, Brazilian parasites form a sister clade to all Mexican gyrodactylids, whose derived clades are distributed in progressively more northerly latitudes in Mexico - the three most-derived species north of the TMVB. This would suggest that gyrodactylid species diverged gradually, presumably as their characid fish hosts colonized and adapted to new environments north of the TMVB.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142406394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unravelling the patterns of exo-erythrocytic development of Haemoproteus parasites (Haemoproteidae, Haemosporida), with a case of abortive tissue stages in a naturally infected bird.","authors":"Mélanie Tchoumbou, Tatjana Iezhova, Carolina Hernández-Lara, Mélanie Duc, Gediminas Valkiūnas","doi":"10.1016/j.ijpara.2024.10.002","DOIUrl":"10.1016/j.ijpara.2024.10.002","url":null,"abstract":"<p><p>Haemoproteus species (Haemosporida, Haemoproteidae) are cosmopolitan blood parasites that affect bird fitness and health. Recent discoveries based on the application of molecular markers showed that exo-erythrocytic or tissue stages of haemoproteids damage various internal organs including the brain. However, the patterns of exo-erythrocytic development remain unclear for most of the described species. This study aimed to understand the exo-erythrocytic development of Haemoproteus parasites in naturally infected Thrush nightingales Luscinia luscinia (Muscicapidae). Infections were confirmed in eight bird individuals by microscopic examination and PCR-based methods. Organs were examined using histology and in situ hybridization, which applied genus-specific and lineage-specific oligonucleotide probes targeting the 18S rRNA of the parasites. Exo-erythrocytic meronts of Haemoproteus attenuatus (lineage hROBIN1) were found and described for the first known time in this avian host. Most meronts were seen in the lungs, with a few also present in the liver, heart, and pectoral muscle. The available data suggest that this parasite produces only meronts, and not megalomeronts. However, numerous megalomeronts at different stages of development were observed in the gizzard and the heart of one individual. Based on the morphology, location in organs, and diagnostics using the lineage-specific probes, the megalomeronts were attributed to Haemoproteus majoris (lineage hWW2). Two cases of empty capsular-like walls of megalomeronts were seen in the gizzard, indicating that the megalomeronts had already ruptured and degenerated. The extensive microscopic examination did not reveal gametocytes of H. majoris, obviously indicating an abortive development. Abortive haemosporidian infections were often speculated to occur in wildlife but have not been documented in naturally infected birds. This study recognised patterns in the exo-erythrocytic development of H. attenuatus, and is to our knowledge the first documentation of abortive Haemoproteus infection in a naturally infected bird during exo-erythrocytic development.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142406395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimized plasmid loading of human erythrocytes for Plasmodium falciparum DNA transfections","authors":"","doi":"10.1016/j.ijpara.2024.04.011","DOIUrl":"10.1016/j.ijpara.2024.04.011","url":null,"abstract":"<div><div>In vitro modification of <span><span>Plasmodium falciparum</span></span> genes is the cornerstone of basic and translational malaria research. Achieved through DNA transfection, these modifications may entail altering protein sequence or abundance. Such experiments are critical for defining the molecular mechanisms of key parasite phenotypes and for validation of drug and vaccine targets. Despite its importance, successful transfection remains difficult and is a resource-intensive, rate-limiting step in <em>P. falciparum</em> research. Here, we report that inefficient loading of plasmid into erythrocytes limits transfection efficacy with commonly used electroporation methods. As these methods also require expensive instrumentation and consumables that are not broadly available, we explored a simpler method based on plasmid loading through hypotonic lysis and resealing of erythrocytes. We used parasite expression of a sensitive NanoLuc reporter for rapid evaluation and optimization of each step. Hypotonic buffer composition, resealing buffer volume and composition, and subsequent incubation affected plasmid retention and successful transfection. While ATP was critical for erythrocyte resealing, addition of Ca⁺⁺ or glutathione did not improve transfection efficiency, with increasing Ca⁺⁺ concentrations proving detrimental to outcomes. Compared with either the standard electroporation method or a previously reported hypotonic loading protocol, the optimized method yields greater plasmid loading and higher expression of the NanoLuc reporter 48 h after transfection. It also produced significantly faster outgrowth of parasites in transfections utilizing either episomal expression or CRISPR-Cas9 mediated integration. This new method produces higher <em>P. falciparum</em> transfection efficiency, reduces resource requirements and should accelerate molecular studies of malaria drug and vaccine targets.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":"54 12","pages":"Pages 597-605"},"PeriodicalIF":3.7,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140891695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}