Pub Date : 2024-10-26DOI: 10.1016/j.ijpara.2024.10.004
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
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.
棘阿米巴虫是一种致病性自由生活阿米巴虫,可引起肉芽肿阿米巴脑炎(GAE)和角膜炎,对于这两种类型的感染,目前还没有适当的治疗方案。由于病原体的新陈代谢是一个有吸引力的治疗目标,我们开始研究卡斯特拉氏阿米巴原虫的能量代谢,并研究滋养体的需氧和厌氧能力。在厌氧条件下,或在存在电子传递链抑制剂的情况下,卡斯特拉氏棘阿米巴滋养体变得浑圆,运动迟缓并停止繁殖。这表明氧气和呼吸链对运动和复制至关重要。此外,细胞色素 c 氧化酶和植物样替代氧化酶这两种末端氧化酶的同时活动对正常功能和复制至关重要。呼吸链不活跃对正常功能的抑制是可逆的。一旦呼吸作用得以恢复,这些圆形的、相当不活跃的变形虫就会在 4 小时内形成棘足,并恢复运动、进食和繁殖。用放射性标记的营养物质进行的实验表明,阿米巴虫更喜欢脂类而不是葡萄糖和氨基酸作为食物。随后的实验表明,在滋养体的标准培养基中添加脂质可大大提高滋养体的生长速度。卡氏棘阿米巴滋养体具有严格的有氧能量代谢和脂肪酸的β-氧化、克雷布斯循环,以及与 ATP 合成酶耦合的有氧电子传递链,可产生大部分用过的 ATP。我们发现,三种已知的脂质氧化抑制剂都能强烈抑制卡斯特氏菌的生长。特别是,硫利达嗪和过氧苯胺在低微摩尔浓度下显示出了强效作用。因此,这项研究揭示了一个新的药物靶点,可能是治疗棘阿米巴感染的新选择。
{"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":"https://doi.org/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":null,"pages":null},"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}
Pub Date : 2024-10-11DOI: 10.1016/j.ijpara.2024.10.003
Jana Martinů, Jan Štefka, Kateřina Vránková, Václav Hypša
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.
寄主特异性的起源和意义是寄生虫学中引人入胜的问题。就单宿主寄生虫与多宿主寄生虫而言,这一课题与专一性/专一性权衡的概念结合在一起。我们利用吸虱多浆虱和啮齿类宿主 Apodemus 的模型来探讨这些概念。研究表明,血清多浆吸虱形成了复杂的遗传结构,其中一个严格特异的 S 系生活在黄腹角雉上,而一个特异性较低的 N 系则生活在黄腹角雉和啮齿目猿猴上。此外,S系形成了两个线粒体支系,它们在地理分布上具有排他性,而且杂交区很窄,这就为检验杂交后体质下降的假说提供了机会。我们在 103 个地点从两种宿主物种中采集了 451 个虱子个体样本。我们使用流行率和强度作为寄生虫在宿主身上实现的适应性的代用指标。与 N 系寄生虫相比,S 系寄生虫在寄主上的流行率和强度明显更高,而 N 系寄生虫在寄主上的流行率和强度明显更低。相反,N系在A. sylvaticus上的流行率和强度都很高,但当虱子种群过于密集时,N系也倾向于使用A. flavicollis。我们讨论了这种差异背后的可能机制(特别是种间竞争,这是专科/专科系统中的典型现象)。我们的结论是,影响虱子流行的主要因素是寄生虫的 "选择",而不是宿主的可及性或种间竞争。我们认为,虱子和老鼠在地理分布上的历史差异可以为观察到的生活策略差异提供可能的解释。与令人信服的 S 系和 N 系流行情况相反,我们并没有在杂交种中发现预期的适应性下降。我们认为杂交区的不稳定性或各自宿主丰度的下降是这一结果的可能解释。
{"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":null,"pages":null},"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}
Pub Date : 2024-10-10DOI: 10.1016/j.ijpara.2024.10.001
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
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.
新热带鱼类蓑鲉属(蓑鲉科)及其相关的蠕虫随着美洲生物大交汇(GABI)从南美洲向北迁移:约 150 种蓑鲉属鱼类遍布南美洲和中美洲,直至墨西哥-美国边境。大多数蛛形纲动物分布在跨墨西哥火山带(TMVB)以南,该火山带将墨西哥一分为二,是新热带地区和近北极地区的主要过渡地带。在这里,我们描述了感染墨西哥Astyanax属的单基因Gyrodactylus属寄生虫的特征:在TMBV以南为Astyanax aeneus,在TMBV以北为Astyanax mexicanus。根据形态学、系统发生学(内部转录隔距(ITS)和细胞色素氧化酶亚单位 II(cox 2))和形态计量数据统计分析,我们确认了 Gyrodactylus pakan 和 Gyrodactylus teken 的有效性,并建立了两个新种 Gyrodactylus aphaa n. sp.这四种旋毛虫是形态上隐蔽物种复合体的一部分,它们在系统发育上彼此密切相关,是寄生于巴西颊蟾蜍的Gyrodactylus carolinae和Gyrodactylus heteracanthus的姊妹物种。四个天旋地转虫系(G. pakan、G. ricardoi n. sp、根据 ITS 系统发育,巴西的寄生虫与所有墨西哥旋毛虫形成姊妹支系,其衍生支系分布在墨西哥逐渐偏北的纬度地区--这是 TMVB 以北衍生最多的三个物种。这表明旋毛虫物种是逐渐分化的,可能是随着其腥臭鱼类宿主在TMVB以北地区定居并适应新环境而分化的。
{"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":null,"pages":null},"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}
Pub Date : 2024-10-09DOI: 10.1016/j.ijpara.2024.10.002
Mélanie Tchoumbou, Tatjana Iezhova, Carolina Hernández-Lara, Mélanie Duc, Gediminas Valkiūnas
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 parasitesin 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 oligonucleotideprobes 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 Haemoproteu smajoris (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.
{"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":"https://doi.org/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 parasitesin 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 oligonucleotideprobes 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 Haemoproteu smajoris (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":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-09","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}
Pub Date : 2024-10-01DOI: 10.1016/j.ijpara.2024.04.011
In vitro modification of Plasmodium falciparum 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 P. falciparum 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 P. falciparum transfection efficiency, reduces resource requirements and should accelerate molecular studies of malaria drug and vaccine targets.
恶性疟原虫基因的体外改造是疟疾基础研究和转化研究的基石。通过 DNA 转染,这些修饰可能会改变蛋白质序列或丰度。此类实验对于确定关键寄生虫表型的分子机制以及验证药物和疫苗靶点至关重要。尽管转染很重要,但成功转染仍然很困难,是恶性疟原虫研究中一个资源密集型的限制性步骤。在此,我们报告了质粒在红细胞中的低效负载限制了常用电穿孔方法的转染效果。由于这些方法还需要昂贵的仪器和耗材,而这些仪器和耗材并不能广泛使用,因此我们探索了一种更简单的方法,即通过低渗裂解红细胞并重新封口来装载质粒。我们利用寄生虫表达敏感的 NanoLuc 报告器来快速评估和优化每个步骤。低渗缓冲液的成分、再封闭缓冲液的容量和成分以及随后的培养都会影响质粒的保留和成功转染。虽然 ATP 对红细胞再封闭至关重要,但添加 Ca++ 或谷胱甘肽并不能提高转染效率,Ca++ 浓度的增加对转染结果不利。与标准电穿孔方法或之前报道的低渗装载方案相比,优化方法能在转染 48 小时后产生更多的质粒装载和更高的 NanoLuc 报告基因表达。在利用外显子表达或 CRISPR-Cas9 介导的整合进行转染时,它还能明显加快寄生虫的生长速度。这种新方法可提高恶性疟原虫的转染效率,减少资源需求,并可加速疟疾药物和疫苗靶标的分子研究。
{"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<sup>++</sup> or glutathione did not improve transfection efficiency, with increasing Ca<sup>++</sup> 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":null,"pages":null},"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}
Pub Date : 2024-10-01DOI: 10.1016/j.ijpara.2024.07.002
Ticks, as hematophagous ectoparasites, can manipulate host immune and metabolic processes, causing tick-borne allergies such as α-Gal syndrome (AGS). Glycolipids with bound galactose-alpha-1–3-galactose (α-Gal) are potential allergenic molecules associated with AGS. Nevertheless, proteins and lipids lacking α-Gal modifications may contribute to tick salivary allergies and be linked to AGS. In this study, we characterized the effect of deglycosylated tick salivary proteins without lipids on treated zebrafish fed with dog food formulated with mammalian (beef, lamb, pork) meat by quantitative proteomics analysis of intestinal samples. The characterization and functional annotations of tick salivary lipids with low representation of glycolipids was conducted using a lipidomics approach. Results showed a significant effect of treatment with saliva and saliva deglycosylated protein fraction on zebrafish abnormal or no feeding (p < 0.005). Treatment with this fraction affected multiple metabolic pathways, defense responses to pathogens and protein metabolism, which correlated with abnormal or no feeding. Lipidomics analysis identified 23 lipid classes with low representation of glycolipids (0.70% of identified lipids). The lipid class with highest representation was phosphatidylcholine (PC; 26.66%) and for glycolipids it corresponded to diacylglycerol (DG; 0.48%). Qualitative analysis of PC antibodies revealed that individuals bitten by ticks were more likely to produce PC-IgG antibodies (p < 0.001). DG levels were significantly higher in tick salivary glands (p < 0.05) compared with tick saliva and salivary fractions. The α-Gal content was higher in tick saliva than in deglycosylated saliva and lipid fractions. These results support a possible role for tick salivary proteins and lipids without α-Gal modifications in AGS.
{"title":"Tick salivary proteome and lipidome with low glycan content correlate with allergic type reactions in the zebrafish model","authors":"","doi":"10.1016/j.ijpara.2024.07.002","DOIUrl":"10.1016/j.ijpara.2024.07.002","url":null,"abstract":"<div><div>Ticks, as hematophagous ectoparasites, can manipulate host immune and metabolic processes, causing tick-borne allergies such as α-Gal syndrome (AGS). Glycolipids with bound galactose-alpha-1–3-galactose (α-Gal) are potential allergenic molecules associated with AGS. Nevertheless, proteins and lipids lacking α-Gal modifications may contribute to tick salivary allergies and be linked to AGS. In this study, we characterized the effect of deglycosylated tick salivary proteins without lipids on treated zebrafish fed with dog food formulated with mammalian (beef, lamb, pork) meat by quantitative proteomics analysis of intestinal samples. The characterization and functional annotations of tick salivary lipids with low representation of glycolipids was conducted using a lipidomics approach. Results showed a significant effect of treatment with saliva and saliva deglycosylated protein fraction on zebrafish abnormal or no feeding (<em>p</em> < 0.005). Treatment with this fraction affected multiple metabolic pathways, defense responses to pathogens and protein metabolism, which correlated with abnormal or no feeding. Lipidomics analysis identified 23 lipid classes with low representation of glycolipids (0.70% of identified lipids). The lipid class with highest representation was phosphatidylcholine (PC; 26.66%) and for glycolipids it corresponded to diacylglycerol (DG; 0.48%). Qualitative analysis of PC antibodies revealed that individuals bitten by ticks were more likely to produce PC-IgG antibodies (<em>p</em> < 0.001). DG levels were significantly higher in tick salivary glands (<em>p</em> < 0.05) compared with tick saliva and salivary fractions. The α-Gal content was higher in tick saliva than in deglycosylated saliva and lipid fractions. These results support a possible role for tick salivary proteins and lipids without α-Gal modifications in AGS.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141792396","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}
Pub Date : 2024-10-01DOI: 10.1016/j.ijpara.2024.06.001
Oocysts of the protozoan Toxoplasma gondii are found in felid feces and can be washed into coastal waters, where they persist for months, attaching to algae and accumulating in invertebrates. We used wild bivalves to assess contamination of coastal waters of the Kerguelen and Galapagos archipelagos by this zoonotic parasite. Additionally, we leveraged the contrasting situations of these archipelagos to identify some potential drivers of contamination. In the Galapagos, with a cat density reaching 142 per km2, 15.38% of the sampled oysters (Saccostrea palmula) tested positive for T. gondii by quantitative real-time PCR (qPCR) (n = 260), and positive samples were found in all eight sampling sites. In Kerguelen, with 1-3 cats per km2, 40.83% of 120 tested mussels (Mytilus edulis platensis) were positive, and positive samples were found in four out of the five sampling sites. These findings provide evidence of T. gondii contamination in the coastal waters of these archipelagos. Furthermore, T. gondii-positive bivalves were found on islands located 20 km away (Galapagos) and 5 km away (Kerguelen) from the nearest cat population, indicating that T. gondii oocysts can disperse through waterborne mechanisms over several kilometers from their initial deposition site. In the Galapagos, where runoff is infrequent and all sites are exposed to currents, the prevalence of qPCR-positive bivalves did not show significant variations between sites (p = 0.107). In Kerguelen where runoff is frequent and site exposure variable, the prevalence varied significantly (p < 0.001). The detection of T. gondii in Kerguelen mussels was significantly correlated with the site exposure to currents (odds ratio (OR) 60.2, p < 0.001) and the on-site density of giant kelp forests (OR 2.624, p < 0.001). This suggests that bivalves can be contaminated not only by oocysts transported by currents but also by consuming marine aggregates containing oocysts that tend to form in kelp forests.
{"title":"Detection of Toxoplasma gondii in wild bivalves from the Kerguelen and Galapagos archipelagos: influence of proximity to cat populations, exposure to marine currents and kelp density","authors":"","doi":"10.1016/j.ijpara.2024.06.001","DOIUrl":"10.1016/j.ijpara.2024.06.001","url":null,"abstract":"<div><div>Oocysts of the protozoan <em>Toxoplasma gondii</em> are found in felid feces and can be washed into coastal waters, where they persist for months, attaching to algae and accumulating in invertebrates. We used wild bivalves to assess contamination of coastal waters of the Kerguelen and Galapagos archipelagos by this zoonotic parasite. Additionally, we leveraged the contrasting situations of these archipelagos to identify some potential drivers of contamination. In the Galapagos, with a cat density reaching 142 per km<sup>2</sup>, 15.38% of the sampled oysters (<em>Saccostrea palmula</em>) tested positive for <em>T. gondii</em> by quantitative real-time PCR (qPCR) (<em>n</em> = 260), and positive samples were found in all eight sampling sites. In Kerguelen, with 1-3 cats per km<sup>2</sup>, 40.83% of 120 tested mussels (<em>Mytilus edulis platensis</em>) were positive, and positive samples were found in four out of the five sampling sites. These findings provide evidence of <em>T. gondii</em> contamination in the coastal waters of these archipelagos. Furthermore, <em>T. gondii</em>-positive bivalves were found on islands located 20 km away (Galapagos) and 5 km away (Kerguelen) from the nearest cat population, indicating that <em>T. gondii</em> oocysts can disperse through waterborne mechanisms over several kilometers from their initial deposition site. In the Galapagos, where runoff is infrequent and all sites are exposed to currents, the prevalence of qPCR-positive bivalves did not show significant variations between sites (<em>p</em> = 0.107). In Kerguelen where runoff is frequent and site exposure variable, the prevalence varied significantly (<em>p</em> < 0.001). The detection of <em>T. gondii</em> in Kerguelen mussels was significantly correlated with the site exposure to currents (odds ratio (OR) 60.2, <em>p</em> < 0.001) and the on-site density of giant kelp forests (OR 2.624, <em>p</em> < 0.001). This suggests that bivalves can be contaminated not only by oocysts transported by currents but also by consuming marine aggregates containing oocysts that tend to form in kelp forests.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141410628","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}
Pub Date : 2024-10-01DOI: 10.1016/j.ijpara.2024.06.002
Fasciola hepatica and Dicrocoelium dendriticum are parasitic trematodes residing in the bile ducts of mammalian hosts, causing, in some cases, impairment of liver function and hepatic fibrosis. Previous studies have shown that extracellular vesicles released by F. hepatica (FhEVs) and D. dendriticum (DdEVs) induce a distinct phenotype in human macrophages, but there is limited information on the effect of parasitic EVs on liver cells, which interact directly with the worms in natural infections. In this study, we isolated FhEVs and DdEVs by size exclusion chromatography and labeled them with a lipophilic fluorescent dye to analyze their uptake by human hepatic stellate cells (HSC) and hepatocytes, important cell types in liver pathology, using synthetic liposomes as internal labeling and uptake control. We analyzed EV uptake and the proteome profiles after the treatment with EVs for both cell types. Our results reveal that EVs establish unique and specific interactions with stellate cells and hepatocytes, suggesting a different role of EVs derived from each parasite, depending on the migration route to reach their final niche. FhEVs have a cytostatic effect on HSCs, but induce the extracellular matrix secretion and elicit anti-inflammatory responses in hepatocytes. DdEVs have a more potent anti-proliferative effect than FhEVs and trigger a global inflammatory response, increasing the levels of NF-κB and other inflammatory mediators in both cell types. These interactions may have a major influence on the progression of the disease, serving to generate conditions that may favor the establishment of the helminths in the host.
{"title":"Unraveling new players in helminth pathology: extracellular vesicles from Fasciola hepatica and Dicrocoelium dendriticum exert different effects on hepatic stellate cells and hepatocytes","authors":"","doi":"10.1016/j.ijpara.2024.06.002","DOIUrl":"10.1016/j.ijpara.2024.06.002","url":null,"abstract":"<div><div><em>Fasciola hepatica</em> and <em>Dicrocoelium dendriticum</em> are parasitic trematodes residing in the bile ducts of mammalian hosts, causing, in some cases, impairment of liver function and hepatic fibrosis. Previous studies have shown that extracellular vesicles released by <em>F. hepatica</em> (<em>Fh</em>EVs) and <em>D. dendriticum</em> (<em>Dd</em>EVs) induce a distinct phenotype in human macrophages, but there is limited information on the effect of parasitic EVs on liver cells, which interact directly with the worms in natural infections. In this study, we isolated <em>Fh</em>EVs and <em>Dd</em>EVs by size exclusion chromatography and labeled them with a lipophilic fluorescent dye to analyze their uptake by human hepatic stellate cells (HSC) and hepatocytes, important cell types in liver pathology, using synthetic liposomes as internal labeling and uptake control. We analyzed EV uptake and the proteome profiles after the treatment with EVs for both cell types. Our results reveal that EVs establish unique and specific interactions with stellate cells and hepatocytes, suggesting a different role of EVs derived from each parasite, depending on the migration route to reach their final niche. <em>Fh</em>EVs have a cytostatic effect on HSCs, but induce the extracellular matrix secretion and elicit anti-inflammatory responses in hepatocytes. <em>Dd</em>EVs have a more potent anti-proliferative effect than <em>Fh</em>EVs and trigger a global inflammatory response, increasing the levels of NF-κB and other inflammatory mediators in both cell types. These interactions may have a major influence on the progression of the disease, serving to generate conditions that may favor the establishment of the helminths in the host.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141456592","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}
Pub Date : 2024-10-01DOI: 10.1016/j.ijpara.2024.06.004
During their journeys, migratory birds encounter a wider range of parasites than residents, transporting them over vast distances. While some parasites are widely distributed, transmission is not inevitable and depends on the presence of competent arthropod vectors as well as parasite compatibility with native bird species. Distinguishing between parasite distribution and transmission areas is crucial for monitoring and assessing risks to native bird species, as distribution areas, with the appropriate conditions, could become potential transmission areas. In this study, blood samples from 455 reed-living birds of the genera Acrocephalus, Locustella, and Emberiza, collected in the nature reserve “Die Reit” in Hamburg, Germany were screened, targeting haemosporidian parasites, trypanosomes, and filarioid nematodes. Determination of migratory bird age was employed to ascertain the transmission area of the detected parasites. Transmission areas were determined, based on information provided by resident and juvenile birds as well as findings in competent vectors. Long-distance migratory birds of the genus Acrocephalus showed a higher prevalence and diversity of blood parasites compared with partially migratory birds such as Emberiza schoeniclus. Notably, an age-dependent difference in parasite prevalence was observed in Acrocephalus spp., but not in E. schoeniclus. Nematodes were absent in all examined bird species. Proposed transmission areas were identified for nine haemosporidian lineages, showing three different types of transmission area, either with limited transmission in Europe or Africa, or active transmission in both regions.
候鸟在旅途中会遇到比本地鸟类更多的寄生虫,并将它们带到很远的地方。虽然有些寄生虫分布广泛,但传播并非不可避免,这取决于是否存在有能力的节肢动物媒介以及寄生虫与本地鸟类物种的兼容性。区分寄生虫分布区和传播区对于监测和评估本地鸟类面临的风险至关重要,因为分布区在适当的条件下可能成为潜在的传播区。本研究对在德国汉堡 "Die Reit "自然保护区采集的 455 只芦苇属鸟类的血液样本进行了筛查,目标是血孢子虫寄生虫、锥虫和丝状线虫。通过确定候鸟年龄来确定检测到的寄生虫的传播区域。根据留鸟和幼鸟提供的信息以及合格病媒的调查结果确定传播区域。与Emberiza schoeniclus等部分候鸟相比,Acrocephalus属的长途迁徙鸟类血液寄生虫的流行率和多样性更高。值得注意的是,在 Acrocephalus 属鸟类中,寄生虫的流行率与年龄有关,而在 E. schoeniclus 中则没有。所有检查过的鸟类都没有线虫。为九个血孢子虫品系确定了拟议的传播区域,显示出三种不同类型的传播区域,要么在欧洲或非洲传播有限,要么在这两个地区传播活跃。
{"title":"Parasite airlines: mapping the distribution and transmission of avian blood parasites in migratory birds","authors":"","doi":"10.1016/j.ijpara.2024.06.004","DOIUrl":"10.1016/j.ijpara.2024.06.004","url":null,"abstract":"<div><div>During their journeys, migratory birds encounter a wider range of parasites than residents, transporting them over vast distances. While some parasites are widely distributed, transmission is not inevitable and depends on the presence of competent arthropod vectors as well as parasite compatibility with native bird species. Distinguishing between parasite distribution and transmission areas is crucial for monitoring and assessing risks to native bird species, as distribution areas, with the appropriate conditions, could become potential transmission areas. In this study, blood samples from 455 reed-living birds of the genera <em>Acrocephalus</em>, <em>Locustella</em>, and <em>Emberiza,</em> collected in the nature reserve “Die Reit” in Hamburg, Germany were screened, targeting haemosporidian parasites, trypanosomes, and filarioid nematodes. Determination of migratory bird age was employed to ascertain the transmission area of the detected parasites. Transmission areas were determined, based on information provided by resident and juvenile birds as well as findings in competent vectors. Long-distance migratory birds of the genus <em>Acrocephalus</em> showed a higher prevalence and diversity of blood parasites compared with partially migratory birds such as <em>Emberiza schoeniclus</em>. Notably, an age-dependent difference in parasite prevalence was observed in <em>Acrocephalus</em> spp., but not in <em>E. schoeniclus</em>. Nematodes were absent in all examined bird species. Proposed transmission areas were identified for nine haemosporidian lineages, showing three different types of transmission area, either with limited transmission in Europe or Africa, or active transmission in both regions.</div></div>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141467799","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}
Pub Date : 2024-09-26DOI: 10.1016/j.ijpara.2024.09.004
Frédéric Douhard, Xavier Matthey, Didier Marcon, Camille Coffre-Thomain, Lucie Estivalet, Delphine Serreau, Fabrice Guégnard, Guillaume Sallé, Papa Moussa Drame, Frédéric Elleboudt, François Lecompte, Hans Adriaensen
Although benefits of selection for host resistance to gastro-intestinal nematodes have long been recognized, its costs on production traits remain unclear. A main difficulty when studying those costs is to disentangle genetic effects due to selection from plastic responses induced by infection. Putative costs of host resistance have been extensively investigated in growing sheep. However, while most of those studies have relied on live weight to assess body growth, more comprehensive assessments accounting for body composition are advocated to detect trade-offs. In this study we used 90 female lambs from lines divergently selected on resistance to Haemonchus contortus that we experimentally infected (n = 60) or not (n = 30) under controlled conditions. As those conditions were defined to enable uninfected lambs to fully express their growth potential, we sought to precisely identify the effects of selection for host resistance on health traits and on growth traits. We assessed muscular and fat growth based on repeated measurements with dorsal ultrasonography for all lambs on farm, and with whole-body computed tomography (CT) scans for a subgroup of 18 infected lambs. Lambs achieved a high growth rate, including infected ones despite their high worm burden (confirmed at necropsy in the subgroup). As expected, lambs from the resistant (R) line were less infected than those from the susceptible (S) line. However, the clear pathogenic effects observed on muscular growth and voluntary feed intake were similar between lines. In contrast, a line difference in body fat was supported both by dorsal and volumetric CT measurements. Specifically, lower fat in the R line compared with the S line was observed equally in infected and uninfected groups, thus providing evidence for a constitutive cost of host resistance. Although this cost is not necessarily disadvantageous in nutrient-rich environments exposing animals to excess fat deposition, its consequences in nutrient-scarce environments may be important to promote sustainable breeding strategies for host resistance.
{"title":"Evidence for a constitutive cost of host resistance on body fat growth in ewe lambs from lines selected for resistance or susceptibility to experimental infections with Haemonchus contortus.","authors":"Frédéric Douhard, Xavier Matthey, Didier Marcon, Camille Coffre-Thomain, Lucie Estivalet, Delphine Serreau, Fabrice Guégnard, Guillaume Sallé, Papa Moussa Drame, Frédéric Elleboudt, François Lecompte, Hans Adriaensen","doi":"10.1016/j.ijpara.2024.09.004","DOIUrl":"10.1016/j.ijpara.2024.09.004","url":null,"abstract":"<p><p>Although benefits of selection for host resistance to gastro-intestinal nematodes have long been recognized, its costs on production traits remain unclear. A main difficulty when studying those costs is to disentangle genetic effects due to selection from plastic responses induced by infection. Putative costs of host resistance have been extensively investigated in growing sheep. However, while most of those studies have relied on live weight to assess body growth, more comprehensive assessments accounting for body composition are advocated to detect trade-offs. In this study we used 90 female lambs from lines divergently selected on resistance to Haemonchus contortus that we experimentally infected (n = 60) or not (n = 30) under controlled conditions. As those conditions were defined to enable uninfected lambs to fully express their growth potential, we sought to precisely identify the effects of selection for host resistance on health traits and on growth traits. We assessed muscular and fat growth based on repeated measurements with dorsal ultrasonography for all lambs on farm, and with whole-body computed tomography (CT) scans for a subgroup of 18 infected lambs. Lambs achieved a high growth rate, including infected ones despite their high worm burden (confirmed at necropsy in the subgroup). As expected, lambs from the resistant (R) line were less infected than those from the susceptible (S) line. However, the clear pathogenic effects observed on muscular growth and voluntary feed intake were similar between lines. In contrast, a line difference in body fat was supported both by dorsal and volumetric CT measurements. Specifically, lower fat in the R line compared with the S line was observed equally in infected and uninfected groups, thus providing evidence for a constitutive cost of host resistance. Although this cost is not necessarily disadvantageous in nutrient-rich environments exposing animals to excess fat deposition, its consequences in nutrient-scarce environments may be important to promote sustainable breeding strategies for host resistance.</p>","PeriodicalId":13725,"journal":{"name":"International journal for parasitology","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142346128","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}