International journal for parasitology最新文献

{"title":"MicroRNA-1 targets ribosomal protein genes to regulate the growth, development and reproduction of Schistosoma japonicum","authors":"Chengsong Sun ,&nbsp;Fang Luo ,&nbsp;Yanmin You ,&nbsp;Mengjie Gu ,&nbsp;Wenbin Yang ,&nbsp;Cun Yi ,&nbsp;Wei Zhang ,&nbsp;Zheng Feng ,&nbsp;Jipeng Wang ,&nbsp;Wei Hu","doi":"10.1016/j.ijpara.2023.03.007","DOIUrl":"10.1016/j.ijpara.2023.03.007","url":null,"abstract":"<div><p>Eggs laid by mature female schistosomes are primarily responsible for the pathogenesis of schistosomiasis and critical for transmission. Consequently, elucidating the mechanism of sexual maturation as well as egg production may lead to new strategies for the control of schistosomiasis. MicroRNAs (miRNAs) are involved in multiple biological processes including reproduction in many organisms, yet their roles have not been well characterized in schistosomes. Here, we investigated microRNA-1 (<em>miR-1</em>), which was downregulated gradually in both male and female <em>Schistosoma japonicum</em> after they reached sexually maturity. The expression of <em>miR-1</em>, as shown with quantitative reverse transcription PCR (qRT-PCR), was lower in the reproductive organs of adult females compared with the somatic tissues. Overexpression of <em>miR-1</em> in adult worms destroyed the morphological architecture of reproductive organs and reduced the subsequent oviposition, which may be due to the activation of apoptosis pathways. Through in silico analysis, 34 potential target genes of <em>miR-1</em> were identified, including five ribosomal protein genes, called <em>rp-s13</em>, <em>rp-l7ae</em>, <em>rp-l14</em>, <em>rp-l11</em> and <em>rp-s24e</em>. In vitro dual-luciferase reporter gene assays and miRNA overexpression experiments further validated that these ribosomal protein genes were directly regulated by <em>miR-1</em>. In contrast to the gene expression of <em>miR-1</em>, qRT-PCR and in situ hybridization experiments demonstrated these ribosomal protein genes were enriched in the sexual organs of adult females. Using RNA interference to silence the ribosomal protein genes in different developmental stages in a mouse model system, we demonstrated that these <em>miR-1</em> target genes not only participated in the reproductive development of <em>S. japonicum</em>, but also were required for the growth and survival of the parasite in the early developmental stages. Taken together, our data suggested that <em>miR-1</em> may affect the growth, reproduction and oviposition of <em>S. japonicum</em> by targeting the ribosomal protein genes, which provides insights for exploration of new anti-schistosome strategies.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10198091","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":"Molecular characterization of Blastocystis and Entamoeba of muskoxen and sheep in Greenland","authors":"Christen Rune Stensvold ,&nbsp;Rebecca P.K.D. Berg ,&nbsp;Jenny G. Maloney ,&nbsp;Aleksey Molokin ,&nbsp;Monica Santin","doi":"10.1016/j.ijpara.2023.05.005","DOIUrl":"10.1016/j.ijpara.2023.05.005","url":null,"abstract":"<div><p>Molecular characterisation of endobionts that are shared among human and non-human hosts can help shed light on the epidemiology and inform studies that aim to unravel the role of these organisms in health and disease. Two of the most common of shared endobionts include the single-celled intestinal protists <em>Blastocystis</em> and <em>Entamoeba</em>. Here, we present the first known data on genetic diversity and host specificity of these two genera in Greenland. Faecal DNA samples from 243 muskoxen and 44 sheep were submitted to metabarcoding of nuclear small subunit ribosomal DNA. <em>Entamoeba-</em> and <em>Blastocystis</em>-specific sequences were clustered, and consensus sequences were subjected to taxonomic query. Using MinION-based sequencing, near-complete nuclear small subunit ribosomal DNA sequences were obtained from four faecal samples. Of the 243 muskox samples, 180 (74%) and 19 (8%) were positive for <em>Blastocystis</em> and <em>Entamoeba</em>, respectively. Forty (91%) and six (14%) of the 44 sheep samples were positive for <em>Blastocystis</em> and <em>Entamoeba</em>, respectively. <em>Blastocystis</em> subtypes (ST) 10, 14, 21, 24–26, and a novel subtype (ST40) were identified. Colonisation by more than one subtype was common. ST40 was common in muskoxen but limited to Northeast Greenland. <em>Entamoeba bovis</em> and the <em>E. bovis</em><span>-associated ribosomal lineages (RL) 1 and 8 were found, and three conditional lineages (CL) 3, 4, and 10 were confirmed; CL10 was promoted to RL12. Several novel lineages were identified, all of which were linked to the </span><em>E. bovis</em> complex. In conclusion, <em>Blastocystis</em> was far more common than <em>Entamoeba</em> and found in approximately three of every four animals; both can be considered common colonisers of large herbivorous mammals in Greenland. Multiple subtypes/lineages of both genera were commonly observed, some of which were novel, but most of which are seen in many other parts of the world.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10204818","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":"Morphological constraint obscures richness: a mitochondrial exploration of cryptic richness in Transversotrema (Trematoda: Transversotrematidae)","authors":"Scott C. Cutmore ,&nbsp;Richard D. Corner ,&nbsp;Thomas H. Cribb","doi":"10.1016/j.ijpara.2023.06.006","DOIUrl":"10.1016/j.ijpara.2023.06.006","url":null,"abstract":"<div><p>Species of <em>Transversotrema</em> Witenberg, 1944 (Transversotrematidae) occupy a unique ecological niche for the Trematoda, living externally under the scales of their teleost hosts. Previous studies of the genus have been impeded partly by limited variation in ribosomal DNA sequence data between closely related species and partly by a lack of morphometrically informative characters. Here, we assess richness of the tropical Indo-west Pacific species through parallel phylogenetic and morphometric analyses, generating cytochrome c oxidase subunit 1 mitochondrial sequence data and morphometric data for hologenophore specimens from Australia, French Polynesia, Japan and Palau. These analyses demonstrate that molecular data provide the only reliable basis for species identification; host distribution, and to a lesser extent morphology, are useful for identifying just a few species of <em>Transversotrema</em>. We infer that a combination of morphological simplicity and infection site constraint has led to the group displaying exceptionally low morphological diversification. Phylogenetic analyses of the mitochondrial data broadly support previous systematic interpretations based on ribosomal data, but also demonstrate the presence of several morphologically and ecologically cryptic species. Ten new species are described, eight from the Great Barrier Reef, Australia (<em>Transversotrema chrysallis</em> n. sp., <em>Transversotrema daphnidis</em> n. sp., <em>Transversotrema enceladi</em> n. sp., <em>Transversotrema hyperionis</em> n. sp., <em>Transversotrema iapeti</em> n. sp., <em>Transversotrema rheae</em> n. sp., <em>Transversotrema tethyos</em> n. sp., and <em>Transversotrema titanis</em> n. sp.) and two from off Japan (<em>Transversotrema methones</em> n. sp. and <em>Transversotrema panos</em> n. sp.). There are now 26 <em>Transversotrema</em> species known from Australian marine fishes, making it the richest trematode genus for the fauna.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10205850","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":"Multinomial logistic regression based on neural networks reveals inherent differences among dairy farms depending on the differential exposure to Fasciola hepatica and Ostertagia ostertagi","authors":"Andreas W. Oehm ,&nbsp;Markus Leinmueller ,&nbsp;Yury Zablotski ,&nbsp;Amely Campe ,&nbsp;Martina Hoedemaker ,&nbsp;Andrea Springer ,&nbsp;Daniela Jordan ,&nbsp;Christina Strube ,&nbsp;Gabriela Knubben-Schweizer","doi":"10.1016/j.ijpara.2023.05.006","DOIUrl":"10.1016/j.ijpara.2023.05.006","url":null,"abstract":"<div><p><em>Fasciola hepatica</em> and <em>Ostertagia ostertagi</em> are cattle parasites with worldwide relevance for economic outcome as well as animal health and welfare. The on-farm exposure of cattle to both parasites is a function of host-associated, intrinsic, as well as environmental and farm-specific, extrinsic, factors. Even though knowledge on the biology of both parasites exists, sophisticated and innovative modelling approaches can help to deepen our understanding of key aspects fostering the exposure of dairy cows to these pathogens. In the present study, multiple multinomial logistic regression models were fitted via neural networks to describe the differences among farms where cattle were not exposed to either <em>F. hepatica</em> or <em>O. ostertagi</em>, to one parasite, or to both, respectively. Farm-specific production and management characteristics were used as covariates to portray these differences. This elucidated inherent farm characteristics associated with parasite exposure. In both studied regions, pasture access for cows, farm-level milk yield, and lameness prevalence were identified as relevant factors. In region ‘South’, adherence to organic farming principles was a further covariate of importance. In region ‘North’, the prevalence of cows with a low body condition score, herd size, hock lesion prevalence, farm-level somatic cell count, and study year appeared to be of relevance. The present study broadens our understanding of the complex epidemiological scenarios that could predict differential farm-level parasite status. The analyses have revealed the importance of awareness of dissimilarities between farms in regard to the differential exposure to <em>F. hepatica</em> and <em>O. ostertagi</em>. This provides solid evidence that dynamics and relevant factors differ depending on whether or not cows are exposed to <em>F. hepatica, O. ostertagi</em>, or to both.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10198095","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":"Functional characterization of a conserved membrane protein, Pbs54, involved in gamete fertilization in Plasmodium berghei","authors":"Wei Pang ,&nbsp;Jie Bai ,&nbsp;Liying Zhu ,&nbsp;Fei Liu ,&nbsp;Yudi Wu ,&nbsp;Fan Yang ,&nbsp;Li Zheng ,&nbsp;Pengbo Liu ,&nbsp;Yaowen Zhang ,&nbsp;Meilian Wang ,&nbsp;Jun Li ,&nbsp;Xiaotong Zhu ,&nbsp;Liwang Cui ,&nbsp;Yaming Cao","doi":"10.1016/j.ijpara.2023.08.003","DOIUrl":"10.1016/j.ijpara.2023.08.003","url":null,"abstract":"<div><p>The successful completion of gamete fertilization is essential for malaria parasite transmission, and this process can be targeted by intervention strategies. In this study, we identified a conserved gene (PBANKA_0813300) in the rodent malaria parasite <em>Plasmodium berghei</em>, which encodes a protein of 54 kDa (designated as Pbs54). Localization studies indicated that Pbs54 is associated with the plasma membranes of gametes and ookinetes. Functional studies by gene disruption showed that the <em>Δpbs54</em> parasites had no defect in asexual proliferation, gametocyte development, or gametogenesis. However, the interactions between male and female gametes were significantly decreased compared with wild-type parasites. The <em>Δpbs54</em> lines did not show a further reduction in zygote and ookinete numbers during in vitro culture, indicating that the defects were probably restricted to gamete fertilization. Consistent with this finding, mosquitoes fed on <em>Δpbs54</em>-infected mice showed a 30.1% reduction in infection prevalence and a 74.7% reduction in oocyst intensity. Cross-fertilization assay indicated that both male and female gametes were impaired in the <em>Δpbs54</em> parasites. To evaluate its transmission-blocking potential, we obtained polyclonal antibodies from mice immunized with the recombinant Pbs54 (rPbs54) protein. In vitro assays showed that anti-rPbs54 sera inhibited ookinete formation by 42.7%. Our experiments identified Pbs54 as a fertility factor required for mosquito transmission and a novel candidate for a malaria transmission-blocking vaccine.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41123160","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":"Cryptosporidium equi n. sp. (Apicomplexa: Cryptosporidiidae): Biological and genetic characterisations","authors":"Jianbo Huang ,&nbsp;Ming Chen ,&nbsp;Yongli He ,&nbsp;Haoyu Chen ,&nbsp;Mingming Huang ,&nbsp;Na Li ,&nbsp;Una Ryan ,&nbsp;Martin Kváč ,&nbsp;Yaoyu Feng ,&nbsp;Lihua Xiao ,&nbsp;Yaqiong Guo","doi":"10.1016/j.ijpara.2023.02.008","DOIUrl":"10.1016/j.ijpara.2023.02.008","url":null,"abstract":"<div><p>The horse genotype is one of three common <em>Cryptosporidium</em> spp. in equine animals and has been identified in some human cases. The species status of <em>Cryptosporidium</em> horse genotype remains unclear due to the lack of extensive morphological, biological, and genetic data. In the present study, we have conducted biological and whole genome sequence analyses of an isolate of the genotype from hedgehogs and proposed to name it <em>Cryptosporidium equi</em> n. sp. to reflect its common occurrence in equine animals. Oocysts of <em>C. equi</em> measured 5.12 ± 0.36 μm × 4.46 ± 0.21 μm with a shape index of 1.15 ± 0.08 (<em>n</em> = 50). <em>Cryptosporidium equi</em> was infectious to 3-week-old four-toed hedgehogs (<em>Atelerix albiventris</em>) and mice, with a prepatent period of 2–9 days and a patent period of 30–40 days in hedgehogs. It was not infectious to rats and rabbits. Phylogenetic analyses of small subunit rRNA, 70 kDa heat shock protein, actin, 60 kDa glycoprotein and 100 other orthologous genes revealed that <em>C. equi</em> is genetically distinct from other known <em>Cryptosporidium</em> species and genotypes. The sequence identity between <em>C. equi</em> and <em>Cryptosporidium parvum</em> genomes is 97.9%. Compared with <em>C. parvum</em>, <em>C. equi</em> has lost two MEDLE genes and one insulinase-like protease gene and gained one SKSR gene. In addition, 60 genes have highly divergent sequences (sequence differences ≥ 5.0%), including those encoding mucin-like glycoproteins, insulinase-like peptidases, and MEDLE and SKSR proteins. The genetic uniqueness of <em>C. equi</em> supports its increasing host range and the naming of it as a valid <em>Cryptosporidium</em> species. This is the first known use of whole genome sequence data in delineating new <em>Cryptosporidium</em> species.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10317503","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":"Complete mitochondrial exploration of Echinococcus multilocularis from French alveolar echinococcosis patients","authors":"Louis Bohard ,&nbsp;Séverine Lallemand ,&nbsp;Romain Borne ,&nbsp;Sandra Courquet ,&nbsp;Solange Bresson-Hadni ,&nbsp;Carine Richou ,&nbsp;Laurence Millon ,&nbsp;Anne-Pauline Bellanger ,&nbsp;Jenny Knapp","doi":"10.1016/j.ijpara.2023.03.006","DOIUrl":"10.1016/j.ijpara.2023.03.006","url":null,"abstract":"<div><p>Alveolar echinococcosis (AE) is a parasitosis that is expanding worldwide, including in Europe. The development of genotypic markers is essential to follow its spatiotemporal evolution. Sequencing of the commonly used mitochondrial genes <em>cob</em>, <em>cox1</em>, and <em>nad2</em> shows low discriminatory power, and analysis of the microsatellite marker EmsB does not allow nucleotide sequence analysis. We aimed to develop a new method for the genotyping of <em>Echinococcus multilocularis</em> based on whole mitochondrial genome (mitogenome) sequencing, to determine the genetic diversity among 30 human visceral samples from French patients, and compare this method with those currently in use. Sequencing of the whole mitochondrial genome was carried out after amplification by PCR, using one uniplex and two multiplex reactions to cover the 13,738 bp of the mitogenome, combined with Illumina technology. Thirty complete mitogenome sequences were obtained from AE lesions. One showed strong identity with Asian genotypes (99.98% identity) in a patient who had travelled to China. The other 29 mitogenomes could be differentiated into 13 haplotypes, showing higher haplotype and nucleotide diversity than when using the <em>cob</em>, <em>cox1</em>, and <em>nad2</em> gene sequences alone. The mitochondrial genotyping data and EmsB profiles did not overlap, probably because one method uses the mitochondrial genome and the other the nuclear genome. The pairwise fixation index (F_st) value between individuals living inside and those living outside the endemic area was high (F_st = 0.222, <em>P</em> = 0.002). This is consistent with the hypothesis of an expansion from historical endemic areas to peripheral regions.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9943289","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":"Host brood traits, independent of adult behaviours, reduce Varroa destructor mite reproduction in resistant honeybee populations","authors":"Nicholas Scaramella ,&nbsp;Ashley Burke ,&nbsp;Melissa Oddie ,&nbsp;Bjørn Dahle ,&nbsp;Joachim R. de Miranda ,&nbsp;Fanny Mondet ,&nbsp;Peter Rosenkranz ,&nbsp;Peter Neumann ,&nbsp;Barbara Locke","doi":"10.1016/j.ijpara.2023.04.001","DOIUrl":"10.1016/j.ijpara.2023.04.001","url":null,"abstract":"<div><p>The ectoparasitic mite <em>Varroa destructor</em> is an invasive species of Western honey bees (<em>Apis mellifera</em>) and the largest pathogenic threat to their health world-wide. Its successful invasion and expansion is related to its ability to exploit the worker brood for reproduction, which results in an exponential population growth rate in the new host. With invasion of the mite, wild honeybee populations have been nearly eradicated from Europe and North America, and the survival of managed honeybee populations relies on mite population control treatments. However, there are a few documented honeybee populations surviving extended periods without control treatments due to adapted host traits that directly impact <em>Varroa</em> mite fitness. The aim of this study was to investigate if <em>Varroa</em> mite reproductive success was affected by traits of adult bee behaviours or by traits of the worker brood, in three mite-resistant honey bee populations from Sweden, France and Norway. The mite’s reproductive success was measured and compared in broods that were either exposed to, or excluded from, adult bee access. Mite-resistant bee populations were also compared with a local mite-susceptible population, as a control group. Our results show that mite reproductive success rates and mite fecundity in the three mite-resistant populations were significantly different from the control population, with the French and Swedish populations having significantly lower reproductive rates than the Norwegian population. When comparing mite reproduction in exposed or excluded brood treatments, no differences were observed, regardless of population. This result clearly demonstrates that <em>Varroa</em> mite reproductive success can be suppressed by traits of the brood, independent of adult worker bees.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9945959","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":"mt-LAF3 is a pseudouridine synthase ortholog required for mitochondrial rRNA and mRNA gene expression in Trypanosoma brucei","authors":"Suzanne M. McDermott ,&nbsp;Vy Pham ,&nbsp;Isaac Lewis ,&nbsp;Maxwell Tracy ,&nbsp;Kenneth Stuart","doi":"10.1016/j.ijpara.2023.04.002","DOIUrl":"10.1016/j.ijpara.2023.04.002","url":null,"abstract":"<div><p><em>Trypanosoma brucei</em> and related kinetoplastid parasites possess unique RNA processing pathways, including in their mitochondria, that regulate metabolism and development. Altering RNA composition or conformation through nucleotide modifications is one such pathway, and modifications including pseudouridine regulate RNA fate and function in many organisms. We surveyed pseudouridine synthase (PUS) orthologs in trypanosomatids, with a particular interest in mitochondrial enzymes due to their potential importance for mitochondrial function and metabolism. <em>Trypanosoma brucei</em> mitochondrial (mt)-LAF3 is an ortholog of human and yeast mitochondrial PUS enzymes, and a mitoribosome assembly factor, but structural studies differ in their conclusion as to whether it has PUS catalytic activity. Here, we generated <em>T. brucei</em> cells that are conditionally null (CN) for mt-LAF3 expression and showed that mt-LAF3 loss is lethal and disrupts mitochondrial membrane potential (ΔΨm). Addition of a mutant gamma ATP synthase allele to the CN cells permitted ΔΨm maintenance and cell survival, allowing us to assess primary effects on mitochondrial RNAs. As expected, these studies showed that loss of mt-LAF3 dramatically decreases levels of mitochondrial <em>12S</em> and <em>9S</em> rRNAs. Notably, we also observed decreases in mitochondrial mRNA levels, including differential effects on edited vs. pre-edited mRNAs, indicating that mt-LAF3 is required for mitochondrial rRNA and mRNA processing, including of edited transcripts. To assess the importance of PUS catalytic activity in mt-LAF3 we mutated a conserved aspartate that is necessary for catalysis in other PUS enzymes and showed it is not essential for cell growth, or maintenance of ΔΨm and mitochondrial RNA levels. Together, these results indicate that mt-LAF3 is required for normal expression of mitochondrial mRNAs in addition to rRNAs, but that PUS catalytic activity is not required for these functions. Instead, our work, combined with previous structural studies, suggests that <em>T. brucei</em> mt-LAF3 acts as a mitochondrial RNA-stabilizing scaffold.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10527287/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9997488","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":"Exo-erythrocytic development of two Haemoproteus species (Haemosporida, Haemoproteidae), with description of Haemoproteus dumbbellus, a new blood parasite of bunting birds (Emberizidae)","authors":"Mélanie Duc ,&nbsp;Tanja Himmel ,&nbsp;Mikas Ilgūnas ,&nbsp;Vytautas Eigirdas ,&nbsp;Herbert Weissenböck ,&nbsp;Gediminas Valkiūnas","doi":"10.1016/j.ijpara.2023.02.009","DOIUrl":"10.1016/j.ijpara.2023.02.009","url":null,"abstract":"<div><p>Avian haemosporidians are widespread parasites categorized into four families of the order Haemosporida (Apicomplexa). Species of the subgenus <em>Parahaemoproteus</em> (genus <em>Haemoproteus</em>) belong to the Haemoproteidae and are transmitted by <em>Culicoides</em> biting midges. Reports of death due to tissue damage during haemoproteosis in non-adapted birds have raised concerns about these pathogens, especially as their exo-erythrocytic development is known for only a few <em>Haemoproteus</em> spp. More research is needed to better understand the patterns of the parasites’ development in tissues and their impact on avian hosts. Yellowhammers <em>Emberiza citrinella</em> (Emberizidae) and common house martins <em>Delichon urbicum</em> (Hirundinidae) were screened for <em>Haemoproteus</em> parasites by microscopic examination of blood films and PCR-based testing. Individuals with single infection were selected for histological investigations. H &amp; E-stained sections were screened for detection and characterization of the exo-erythrocytic stages, while chromogenic <em>in situ</em> hybridization (CISH) and phylogenetic analysis were performed to confirm the <em>Haemoproteus</em> origin and their phylogenetic relationships. <em>Haemoproteus dumbbellus</em> n. sp. was discovered in <em>Emberiza citrinella</em> single<em>-</em>infected with the lineage hEMCIR01. Meronts of <em>H. dumbbellus</em> n. sp. developed in various organs of five of six tested individuals, a pattern which was reported in other <em>Haemoproteus</em> species clustering in the same clade, suggesting this could be a phylogenetic trait. By contrast, in <em>Delichon urbicum</em> infected with the <em>Haemoproteus</em> lineage hDELURB2, which was linked to the more distantly related parasite <em>Haemoproteus hirundinis</em>, only megalomeronts were found in the pectoral muscles of two of six infected individuals. All exo-erythrocytic stages were confirmed to be <em>Haemoproteus</em> parasites by CISH using a <em>Haemoproteus</em> genus-specific probe. While the development of meronts seems to be typical for species of the clade containing <em>H. dumbbellus</em>, further investigations and data from more species are needed to explore whether a phylogenetic pattern occurs in meront or megalomeront formation.</p></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10299804","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}