Pub Date : 2024-10-24DOI: 10.1016/j.jip.2024.108224
Sebastian Prati , Sonja Rückert , Daniel S. Grabner , Bernd Sures , Jamie Bojko
We describe a novel sanguicolous parasitic ciliate, Metacollinia emscheri n. sp., found in the freshwater amphipods Gammarus pulex and G. fossarum. This ciliate infected 8.05 % of the amphipods collected in a German stream catchment, the Boye, a tributary of the river Emscher. The ciliate showed morphological characteristics fitting the genus Metacollinia. Different life stages of variable size occurred simultaneously in the hemocoel throughout the hosts’ body. The tomont had 40–47 slightly spiraled kineties, a non-ciliated cortical band, a large macronucleus, and contractile vacuoles arranged in rows or scattered throughout the cytoplasm. The protomites/tomites with nine somatic kineties presented evidence of the buccal kineties x, y, and z reminiscent of those of the order Foettingeriida. Phylogenetic analyses of the 18S rRNA and COI regions confirm the ciliate placement in the Collinidae and a close relatedness to the type species of the genus Metacollinia, Metacollinia luciensis.
We formally describe this new parasite as Metacollinia emscheri n. sp. using pathological, morphological, and nuclear/mitochondrial genetic data. The systemic infections observed in histological preparations and the pathogenicity of Metacollinia emscheri n. sp. suggest that this parasite might influence host population dynamics. Given the ecological importance of amphipods as keystone species in freshwater ecosystems, an outbreak of this parasite might indirectly impact ecosystem functioning.
我们描述了一种寄生在淡水片脚类动物 Gammarus pulex 和 G. fossarum 身上的新型鞘翅目纤毛虫 Metacollinia emscheri n. sp.。这种纤毛虫感染了 8.05%在德国埃姆舍尔河支流博耶河流域收集到的片脚类动物。这种纤毛虫的形态特征符合 Metacollinia 属。大小不一的不同生命阶段同时出现在宿主全身的血肠中。体细胞内有 40-47 个略呈螺旋状的动子、一条无纤毛的皮质带、一个大核和成排或散布在整个细胞质中的收缩空泡。具有九个体节的原节/体节显示了颊节x、y和z,让人联想到Foettingeriida目。18S rRNA 和 COI 区域的系统发育分析证实,该纤毛虫属于科林科,与 Metacollinia 属的模式种 Metacollinia luciensis 关系密切。我们利用病理学、形态学和核/半知子体遗传学数据将这种新寄生虫正式描述为 Metacollinia emscheri n. sp.。组织学制剂中观察到的系统性感染以及 Metacollinia emscheri n. sp.的致病性表明,这种寄生虫可能会影响宿主的种群动态。鉴于片脚类动物在淡水生态系统中作为关键物种的生态重要性,这种寄生虫的爆发可能会间接影响生态系统的功能。
{"title":"Metacollinia emscheri n. sp., a novel sanguicolous apostome ciliate of freshwater amphipods (Gammarus spp.)","authors":"Sebastian Prati , Sonja Rückert , Daniel S. Grabner , Bernd Sures , Jamie Bojko","doi":"10.1016/j.jip.2024.108224","DOIUrl":"10.1016/j.jip.2024.108224","url":null,"abstract":"<div><div>We describe a novel sanguicolous parasitic ciliate, <em>Metacollinia emscheri</em> n. sp., found in the freshwater amphipods <em>Gammarus pulex</em> and <em>G. fossarum</em>. This ciliate infected 8.05 % of the amphipods collected in a German stream catchment, the Boye, a tributary of the river Emscher. The ciliate showed morphological characteristics fitting the genus <em>Metacollinia</em>. Different life stages of variable size occurred simultaneously in the hemocoel throughout the hosts’ body. The tomont had 40–47 slightly spiraled kineties, a non-ciliated cortical band, a large macronucleus, and contractile vacuoles arranged in rows or scattered throughout the cytoplasm. The protomites/tomites with nine somatic kineties presented evidence of the buccal kineties x, y, and z reminiscent of those of the order Foettingeriida. Phylogenetic analyses of the 18S rRNA and COI regions confirm the ciliate placement in the Collinidae and a close relatedness to the type species of the genus <em>Metacollinia</em>, <em>Metacollinia luciensis</em>.</div><div>We formally describe this new parasite as <em>Metacollinia emscheri</em> n. sp. using pathological, morphological, and nuclear/mitochondrial genetic data. The systemic infections observed in histological preparations and the pathogenicity of <em>Metacollinia emscheri</em> n. sp. suggest that this parasite might influence host population dynamics. Given the ecological importance of amphipods as keystone species in freshwater ecosystems, an outbreak of this parasite might indirectly impact ecosystem functioning.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"207 ","pages":"Article 108224"},"PeriodicalIF":3.6,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142502200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-23DOI: 10.1016/j.jip.2024.108225
Antonella Cuniolo , María Victoria Martin , Corina M Berón
Culex quinquefasciatus is a hematophagous mosquito, widely distributed around the world, that plays a crucial role in public and veterinary health. As an efficient vector of etiological agents, it exhibits a marked preference for urban environments and human blood. Despite advances in mosquito-borne disease control, managing mosquito populations remains an economically efficient and safe strategy to reduce the impact of epidemic outbreaks. However, achieving this goal requires ecologically acceptable tools that ensure sustainability and minimize adverse environmental impacts. In the present work, we investigated the effect of a non-toxigenic model cyanobacterium on Cx. quinquefasciatus larvae through regulated cell death. We observed that heat stress treatment of Synechocystis PCC 6803 inducing ferroptosis, results in larval lipid oxidation, leading to their death. This effect can be mitigated by rearing larvae in an environment containing canonical inhibitors of ferroptosis, such as ferrostatin 1, or antioxidants, like glutathione and ascorbic acid. Furthermore, larval cell death induced by ferroptotic cyanobacteria is closely linked to oxidative dysregulation and lipid peroxidation, both hallmarks of ferroptosis. Moreover, while ferroptotic Synechocystis significantly affects larval development, it does not influence oviposition site selection by gravid females.
{"title":"Ferroptotic cyanobacteria as biocontrol agent of the southern house mosquito Culex quinquefasciatus","authors":"Antonella Cuniolo , María Victoria Martin , Corina M Berón","doi":"10.1016/j.jip.2024.108225","DOIUrl":"10.1016/j.jip.2024.108225","url":null,"abstract":"<div><div><em>Culex quinquefasciatus</em> is a hematophagous mosquito, widely distributed around the world, that plays a crucial role in public and veterinary health. As an efficient vector of etiological agents, it exhibits a marked preference for urban environments and human blood. Despite advances in mosquito-borne disease control, managing mosquito populations remains an economically efficient and safe strategy to reduce the impact of epidemic outbreaks. However, achieving this goal requires ecologically acceptable tools that ensure sustainability and minimize adverse environmental impacts. In the present work, we investigated the effect of a non-toxigenic model cyanobacterium on <em>Cx. quinquefasciatus</em> larvae through regulated cell death. We observed that heat stress treatment of <em>Synechocystis</em> PCC 6803 inducing ferroptosis, results in larval lipid oxidation, leading to their death. This effect can be mitigated by rearing larvae in an environment containing canonical inhibitors of ferroptosis, such as ferrostatin 1, or antioxidants, like glutathione and ascorbic acid. Furthermore, larval cell death induced by ferroptotic cyanobacteria is closely linked to oxidative dysregulation and lipid peroxidation, both hallmarks of ferroptosis. Moreover, while ferroptotic <em>Synechocystis</em> significantly affects larval development, it does not influence oviposition site selection by gravid females.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"207 ","pages":"Article 108225"},"PeriodicalIF":3.6,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142502202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ribosomal proteins are considered to be involved in the immunity of different animals against pathogens. The protein level of RPL23 increased after fungal infection in termites, but how it influence active immunity in termites is unknown. The role of RPL23 gene was studied to evaluate its impact on active immunity of termite Reticulitermes chinensis against entomopathogenic fungus (EPF) Metarhizium anisopliae. The RPL23 gene fragment (414 bp) was cloned and phylogenetic analysis revealed that it’s very close to termite Coptotermes formosanus. Expression of RPL23 gene was significantly higher in abdomen as compared to thorax and head. Silencing RPL23 gene had no significant impact on the frequency and time of allogrooming towards fungus exposed termites from nestmates, which showed that nestmates acquired spores from infected termites through allogrooming. Expression of immune genes (GNBP1, GNBP2 and phenoloxidase) and apoptosis related genes (TNF-α, caspase 1, caspase 3 and caspase 8) decreased significantly in nestmates of fungus-treated termites after silencing of RPL23 gene as compared to control. Antifungal activity and survival of RPL23 silenced nestmates of fungus-treated termites also decreased. To sum up, this study found that silencing of RPL23 gene broke the active immunity against M. anisopliae infection, reduced the antifungal activity of termites, weakened cell apoptosis, and led to increased mortality of termites, which may help to find a potential alternative for chemical insecticides to control termites.
{"title":"Study on the role of RPL23 gene in active immunity of termite Reticulitermes chinensis against Metarhizium anisopliae","authors":"Shuxin Yu , Ali Hassan , Nasir Mehmood , Wei Zhou , Taqi Raza , Qiuying Huang","doi":"10.1016/j.jip.2024.108226","DOIUrl":"10.1016/j.jip.2024.108226","url":null,"abstract":"<div><div>Ribosomal proteins are considered to be involved in the immunity of different animals against pathogens. The protein level of RPL23 increased after fungal infection in termites, but how it influence active immunity in termites is unknown. The role of <em>RPL23</em> gene was studied to evaluate its impact on active immunity of termite <em>Reticulitermes chinensis</em> against entomopathogenic fungus (EPF) <em>Metarhizium anisopliae</em>. The <em>RPL23</em> gene fragment (414 bp) was cloned and phylogenetic analysis revealed that it’s very close to termite <em>Coptotermes formosanus</em>. Expression of <em>RPL23</em> gene was significantly higher in abdomen as compared to thorax and head. Silencing <em>RPL23</em> gene had no significant impact on the frequency and time of allogrooming towards fungus exposed termites from nestmates, which showed that nestmates acquired spores from infected termites through allogrooming. Expression of immune genes (<em>GNBP1</em>, <em>GNBP2</em> and phenoloxidase) and apoptosis related genes (<em>TNF-α,</em> caspase 1, caspase 3 and caspase 8) decreased significantly in nestmates of fungus-treated termites after silencing of <em>RPL23</em> gene as compared to control. Antifungal activity and survival of <em>RPL23</em> silenced nestmates of fungus-treated termites also decreased. To sum up, this study found that silencing of <em>RPL23</em> gene broke the active immunity against <em>M. anisopliae</em> infection, reduced the antifungal activity of termites, weakened cell apoptosis, and led to increased mortality of termites, which may help to find a potential alternative for chemical insecticides to control termites.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"207 ","pages":"Article 108226"},"PeriodicalIF":3.6,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142502201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-15DOI: 10.1016/j.jip.2024.108217
Maria D. Cassells , Niamh Treanor , Emigdio Jordán Muñoz-Adalia , Christine T. Griffin
Insect cadavers infected by entomopathogenic nematodes (EPN) are defended against scavengers by chemical mechanisms and other means. Despite these defences, the cadaver may be bitten before being rejected. In this study, we investigated the effect of damage to the cadaver cuticle on the fitness of nematodes (Heterorhabditis downesi Stock, Griffin & Burnell or Steinernema feltiae Filipjev) developing inside. We first quantified the severity of scavenger damage to EPN-infected Galleria mellonella Linnaeus cadavers in the field, and separately, with crickets (Gryllus bimaculatus De Geer) in the laboratory. In both field and laboratory, EPN-infected cadavers suffered less damage than freeze-killed controls, and damage consisted mainly of small lesions to the cuticle. In further experiments, scavenging damage was simulated shortly after death of infected cadavers by piercing the cuticle 0, 1, 3 or 5 times and incubating in moist (100% relative humidity (RH)) or dry (60–70% RH) conditions. The greater the level of damage, the greater the loss of moisture from the cadaver (estimated by weight loss), and this was exacerbated in dry conditions. The number of infective juveniles (IJs) emerging from H. downesi-infected cadavers was significantly reduced by damage, especially in dry conditions. In addition, emerging IJs were progressively smaller with increasing damage. For this species, the number of IJs was negatively correlated with moisture loss, indicating that the reduction in fitness was mediated by desiccation. For S. feltiae, damage impacted IJ number to a lesser extent and size was not affected. The reduction in numbers was not explained by moisture loss, indicating that for S. feltiae, some factor other than desiccation (perhaps competition with opportunistic microbes) impacts the nematodes when the cuticle is damaged. The greater vulnerability of H. downesi, compared to S. feltiae, to scavenger damage to the host cadaver may be due to its longer developmental time in the host resulting in longer exposure to damaging conditions. In conclusion, damage simulating biting by scavengers impacts the fitness of EPN, with the effect depending on nematode species, environmental conditions and the extent of damage. These findings have implications for the success of field application of EPN in infected cadavers.
被昆虫病原线虫(EPN)感染的昆虫尸体会通过化学和其他手段来抵御食腐动物。尽管有这些防御措施,昆虫尸体仍有可能在被排斥前被咬伤。在这项研究中,我们调查了尸体角质层受损对在其内部发育的线虫(Heterorhabditis downesi 或 Steinernema feltiae)生存能力的影响。我们首先在野外量化了清道夫对受EPN感染的林奈瘿蚊尸体的破坏程度,并在实验室分别量化了蟋蟀(Gryllus bimaculatus De Geer)的破坏程度。在野外和实验室中,与冷冻杀死的对照组相比,受 EPN 感染的尸体受到的损害较小,损害主要是角质层的小损伤。在进一步的实验中,在受感染的尸体死后不久,通过刺穿表皮 0、1、3 或 5 次,并在潮湿(相对湿度为 100%)或干燥(相对湿度为 60-70%)的条件下培养,来模拟清扫损伤。损伤程度越大,尸体的水分损失越多(按体重损失估算),而在干燥条件下,这种损失会加剧。受 H. downesi 感染的尸体中出现的感染性幼体(IJs)数量因损坏而显著减少,尤其是在干燥条件下。此外,随着损害程度的增加,新出现的感染幼体的数量也在逐渐减少。该物种的 IJ 数量与水分损失呈负相关,这表明适应性的降低是由干燥引起的。对于 S. feltiae 而言,损害对 IJ 数量的影响较小,而大小则不受影响。水分损失无法解释数量减少的原因,这表明对于 S. feltiae 而言,当角质层受损时,除干燥外的其他因素(也许是与机会微生物的竞争)也会影响线虫。H. downesi比 S. feltiae更容易受到清道夫对宿主尸体的破坏,这可能是由于它在宿主体内的发育时间更长,导致暴露在破坏性条件下的时间更长。总之,食腐动物模拟咬噬的损害会影响 EPN 的适应性,影响程度取决于线虫种类、环境条件和损害程度。这些发现对在受感染尸体中实地应用 EPN 的成功与否有影响。
{"title":"Damage to the host cadaver, simulating the effects of scavenging, differentially affects fitness of entomopathogenic nematode species","authors":"Maria D. Cassells , Niamh Treanor , Emigdio Jordán Muñoz-Adalia , Christine T. Griffin","doi":"10.1016/j.jip.2024.108217","DOIUrl":"10.1016/j.jip.2024.108217","url":null,"abstract":"<div><div>Insect cadavers infected by entomopathogenic nematodes (EPN) are defended against scavengers by chemical mechanisms and other means. Despite these defences, the cadaver may be bitten before being rejected. In this study, we investigated the effect of damage to the cadaver cuticle on the fitness of nematodes (<em>Heterorhabditis downesi Stock, Griffin & Burnell</em> or <em>Steinernema feltiae Filipjev</em>) developing inside. We first quantified the severity of scavenger damage to EPN-infected <em>Galleria mellonella</em> Linnaeus cadavers in the field, and separately, with crickets <em>(Gryllus bimaculatus</em> De Geer) in the laboratory. In both field and laboratory, EPN-infected cadavers suffered less damage than freeze-killed controls, and damage consisted mainly of small lesions to the cuticle. In further experiments, scavenging damage was simulated shortly after death of infected cadavers by piercing the cuticle 0, 1, 3 or 5 times and incubating in moist (100% relative humidity (RH)) or dry (60–70% RH) conditions. The greater the level of damage, the greater the loss of moisture from the cadaver (estimated by weight loss), and this was exacerbated in dry conditions. The number of infective juveniles (IJs) emerging from <em>H. downesi-</em>infected cadavers was significantly reduced by damage, especially in dry conditions. In addition, emerging IJs were progressively smaller with increasing damage. For this species, the number of IJs was negatively correlated with moisture loss, indicating that the reduction in fitness was mediated by desiccation. For <em>S. feltiae,</em> damage impacted IJ number to a lesser extent and size was not affected. The reduction in numbers was not explained by moisture loss, indicating that for <em>S. feltiae</em>, some factor other than desiccation (perhaps competition with opportunistic microbes) impacts the nematodes when the cuticle is damaged. The greater vulnerability of <em>H. downesi,</em> compared to <em>S. feltiae,</em> to scavenger damage to the host cadaver may be due to its longer developmental time in the host resulting in longer exposure to damaging conditions. In conclusion, damage simulating biting by scavengers impacts the fitness of EPN, with the effect depending on nematode species, environmental conditions and the extent of damage. These findings have implications for the success of field application of EPN in infected cadavers.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"207 ","pages":"Article 108217"},"PeriodicalIF":3.6,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142467749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-15DOI: 10.1016/j.jip.2024.108222
Xiao-Meng Guo , Wen Gao , Hai-Liang Wang , Prapatsorn Wongkhaluang , Suparat Taengchaiyaphum , Guo-Si Xie , Chen Li , Ruo-Heng Zhao , Kallaya Sritunyalucksana , Jie Huang
Microsporidium Ecytonucleospora hepatopenaei (EHP) spores were purified from the hepatopancreas of Penaeus vannamei infected with EHP by percoll density gradient centrifugation and differential centrifugation. The EHP spores contain a thick chitin wall and might not rupture using the routine DNA extraction protocol. In this study, three enzymes were used, including chitinase, proteinase K, and DNase I. Chitinase or proteinase K digestions caused weakened fluorescence of chitin showing by a blurred edge of EHP spores stained with calcofluor white under a fluorescence microscope. Different combinations of these enzymes followed by DNA extraction with phenol–chloroform from EHP spores showed significant increases in the copy number of the EHP SSU gene per spore. The combination of the chitinase and proteinase K treatments resulted 4.46 ± 1.07 copies/spore detected, which is 31.6 ± 20.7 folds of no treatment groups, accounting to (55.7 ± 13.4)% of the total copies of the gene in the spore. The additional treatment with chitinase to the conventional extraction protocol with a proteinase K digestion step for feces and hepatopancreas samples of P. vannamei resulted in a significant difference in EHP copies in the DNA of (83.8 ± 64.1)% and (55.3 ± 88.0)% increases. The study proved that chitinase and proteinase K treatment enhance the DNA extraction from microsporidian spores resulting in high yield.
通过 percoll 密度梯度离心法和差速离心法,从感染了 EHP 的万年青(Penaeus vannamei)肝胰腺中纯化了 Ecytonucleospora hepatopenaei(EHP)小孢子。EHP 孢子含有厚厚的几丁质壁,常规的 DNA 提取方案可能无法使其破裂。甲壳素酶或蛋白酶 K 可使甲壳素的荧光减弱,在荧光显微镜下,用钙氟白染色的 EHP 孢子边缘模糊不清。用酚-氯仿从 EHP 孢子中提取 DNA 后,这些酶的不同组合显示每个孢子的 EHP SSU 基因拷贝数显著增加。几丁质酶和蛋白酶 K 组合处理的结果是每孢子检测到 4.46 ± 1.07 个拷贝,是未处理组的 31.6 ± 20.7 倍,占孢子中该基因总拷贝数的(55.7 ± 13.4)%。在对凡纳滨贝类粪便和肝胰腺样本进行蛋白酶 K 消化步骤的常规提取方案的基础上,再使用几丁质酶处理,结果发现 DNA 中的 EHP 拷贝数有显著差异,分别增加了(83.8 ± 64.1)%和(55.3 ± 88.0)%。该研究证明,几丁质酶和蛋白酶 K 处理可提高微孢子虫孢子的 DNA 提取率,从而获得高产率。
{"title":"Chitinase and proteinase K treatments enhance the DNA yield of microsporidium Ecytonucleospora hepatopenaei spores","authors":"Xiao-Meng Guo , Wen Gao , Hai-Liang Wang , Prapatsorn Wongkhaluang , Suparat Taengchaiyaphum , Guo-Si Xie , Chen Li , Ruo-Heng Zhao , Kallaya Sritunyalucksana , Jie Huang","doi":"10.1016/j.jip.2024.108222","DOIUrl":"10.1016/j.jip.2024.108222","url":null,"abstract":"<div><div>Microsporidium <em>Ecytonucleospora hepatopenaei</em> (EHP) spores were purified from the hepatopancreas of <em>Penaeus vannamei</em> infected with EHP by percoll density gradient centrifugation and differential centrifugation. The EHP spores contain a thick chitin wall and might not rupture using the routine DNA extraction protocol. In this study, three enzymes were used, including chitinase, proteinase K, and DNase I. Chitinase or proteinase K digestions caused weakened fluorescence of chitin showing by a blurred edge of EHP spores stained with calcofluor white under a fluorescence microscope. Different combinations of these enzymes followed by DNA extraction with phenol–chloroform from EHP spores showed significant increases in the copy number of the EHP SSU gene per spore. The combination of the chitinase and proteinase K treatments resulted 4.46 ± 1.07 copies/spore detected, which is 31.6 ± 20.7 folds of no treatment groups, accounting to (55.7 ± 13.4)% of the total copies of the gene in the spore. The additional treatment with chitinase to the conventional extraction protocol with a proteinase K digestion step for feces and hepatopancreas samples of <em>P. vannamei</em> resulted in a significant difference in EHP copies in the DNA of (83.8 ± 64.1)% and (55.3 ± 88.0)% increases. The study proved that chitinase and proteinase K treatment enhance the DNA extraction from microsporidian spores resulting in high yield.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"207 ","pages":"Article 108222"},"PeriodicalIF":3.6,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142467751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-12DOI: 10.1016/j.jip.2024.108220
Robert L. Harrison, Charlotte B. Francoeur, Daniel L. Rowley
A baculovirus had been previously identified in larvae of the zebra caterpillar, Melanchra (formerly Ceramica) picta Harris. To further characterize this virus, two isolates, Melanchra picta nucleopolyhedrovirus-185 (MepiNPV-185) and MepiNPV-600, were fully sequenced. Analysis of the genome sequences revealed that both isolates are members of alphabaculovirus species Alphabaculovirus maconfiguratae, along with alphabaculoviruses of the bertha armyworm, Mamestra configurata Walker. MepiNPV-600 displayed relatively low virulence against larvae of Trichoplusia ni Hübner in bioassays compared to other T. ni-pathogenic alphabaculoviruses. MepiNPV likely arose from a cross-species transfer between M. configurata and M. picta larvae, which often occur together.
以前曾在斑马毛虫 Melanchra(原名 Ceramica)picta Harris 的幼虫体内发现过一种杆状病毒。为了进一步确定这种病毒的特征,对两个分离物--Melanchra picta nucleopolyhedrovirus-185(MepiNPV-185)和 MepiNPV-600 进行了全面测序。对基因组序列的分析表明,这两个分离株都属于阿尔法巴库洛病毒(Alphabaculovirus maconfiguratae)种,同时也是柏树军虫(Mamestra configurata Walker)的阿尔法巴库洛病毒(Alphabaculovirus)种。在生物测定中,MepiNPV-600 对黑毛虫(Trichoplusia ni Hübner)幼虫的致病力相对较低。MepiNPV 很可能是由 M. configurata 和 M. picta 幼虫之间的跨种转移产生的,这两种幼虫经常同时出现。
{"title":"An alphabaculovirus from the zebra caterpillar, Melanchra picta Harris, is an isolate of species Alphabaculovirus maconfiguratae","authors":"Robert L. Harrison, Charlotte B. Francoeur, Daniel L. Rowley","doi":"10.1016/j.jip.2024.108220","DOIUrl":"10.1016/j.jip.2024.108220","url":null,"abstract":"<div><div>A baculovirus had been previously identified in larvae of the zebra caterpillar, <em>Melanchra</em> (formerly <em>Ceramica</em>) <em>picta</em> Harris. To further characterize this virus, two isolates, Melanchra picta nucleopolyhedrovirus-185 (MepiNPV-185) and MepiNPV-600, were fully sequenced. Analysis of the genome sequences revealed that both isolates are members of alphabaculovirus species <em>Alphabaculovirus maconfiguratae</em>, along with alphabaculoviruses of the bertha armyworm, <em>Mamestra configurata</em> Walker. MepiNPV-600 displayed relatively low virulence against larvae of <em>Trichoplusia ni</em> Hübner in bioassays compared to other <em>T. ni</em>-pathogenic alphabaculoviruses. MepiNPV likely arose from a cross-species transfer between <em>M. configurata</em> and <em>M. picta</em> larvae, which often occur together.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"207 ","pages":"Article 108220"},"PeriodicalIF":3.6,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","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.jip.2024.108218
Juliette Gilbert , Laurianne Paris , Aurore Dubuffet, Catherine Texier, Frédéric Delbac, Marie Diogon
Nosema ceranae is an intestinal parasite frequently found in Apis mellifera colonies. This parasite belongs to Microsporidia, a group of obligate intracellular parasites known to be strongly dependent on their host for energy and resources. Previous studies have shown that N. ceranae could alter several metabolic pathways, including those involved in the nutrient storage. To explore the impact of N. ceranae on the fat body reserves, newly emerged summer bees were experimentally infected, and we measured (1) the lipid percentage of the abdominal fat body at 2-, 7- and 14-days post-inoculation (p.i.) using diethyl ether lipid extraction, (2) the triglyceride and protein concentrations by spectrophotometric assay methods, and (3) the amount of intracellular lipid droplets in trophocytes at 14- and 21-days p.i. using Nile Red staining. Comparing the three methods used to evaluate lipid stores, our data revealed that Nile Red staining seemed to be the simplest, fastest and reliable method. Our results first revealed that the percentage of fat body lipids significantly decreased in infected bees at D14 p.i. The protein stores did not seem to be affected by the infection, while triglyceride concentration was reduced by 30% and lipid droplet amount by 50% at D14 p.i. Finally, a similar decrease in lipid droplet reserves in response to N. ceranae infection was observed in bees collected in fall.
{"title":"Nosema ceranae infection reduces the fat body lipid reserves in the honeybee Apis mellifera","authors":"Juliette Gilbert , Laurianne Paris , Aurore Dubuffet, Catherine Texier, Frédéric Delbac, Marie Diogon","doi":"10.1016/j.jip.2024.108218","DOIUrl":"10.1016/j.jip.2024.108218","url":null,"abstract":"<div><div><em>Nosema ceranae</em> is an intestinal parasite frequently found in <em>Apis mellifera</em> colonies. This parasite belongs to Microsporidia, a group of obligate intracellular parasites known to be strongly dependent on their host for energy and resources. Previous studies have shown that <em>N. ceranae</em> could alter several metabolic pathways, including those involved in the nutrient storage. To explore the impact of <em>N. ceranae</em> on the fat body reserves, newly emerged summer bees were experimentally infected, and we measured (1) the lipid percentage of the abdominal fat body at 2-, 7- and 14-days post-inoculation (p.i.) using diethyl ether lipid extraction, (2) the triglyceride and protein concentrations by spectrophotometric assay methods, and (3) the amount of intracellular lipid droplets in trophocytes at 14- and 21-days p.i. using Nile Red staining. Comparing the three methods used to evaluate lipid stores, our data revealed that Nile Red staining seemed to be the simplest, fastest and reliable method. Our results first revealed that the percentage of fat body lipids significantly decreased in infected bees at D14 p.i. The protein stores did not seem to be affected by the infection, while triglyceride concentration was reduced by 30% and lipid droplet amount by 50% at D14 p.i. Finally, a similar decrease in lipid droplet reserves in response to <em>N. ceranae</em> infection was observed in bees collected in fall.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"207 ","pages":"Article 108218"},"PeriodicalIF":3.6,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142406503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","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.jip.2024.108219
Gahyeon Jin , Ji-Seon Jeong , Il-Hwan Kim , Yonggyun Kim
A nematode-symbiotic bacterium, Xenorhabdus hominickii, exhibits two distinct lifestyles. Upon infection of its host nematode into a target insect, X. hominickii is released into the insect hemocoel and becomes pathogenic. This study examines the critical transformation in bacterial life forms concerning the activity of a transcriptional regulator, HexA. When X. hominickii was cultured in tryptic soy broth, HexA was expressed during the stationary phase of bacterial growth. Conversely, HexA was expressed in the early growth stage within the insect host, Spodoptera exigua, when infected with X. hominickii. The transient expression of HexA was succeeded by the expression of another transcriptional regulator, Lrp, which led to the production of bacterial virulent factors. Expression of HexA was manipulated by replacing its promoter with an inducible promoter controlled by the inducer, l-arabinose. In the absence of the inducer, the mutant bacteria expressed HexA at a low level, resulting in a bacterial culture broth that was more effective at suppressing insect immune responses than the wild type. When the inducer was added, HexA was expressed at high levels, rendering the culture broth ineffective in immunosuppression. Interestingly, expression of HexA inhibited the expression of another transcriptional regulator, Lrp, which in turn induced the expression of a non-ribosomal peptide synthetase, gxpS, leading to the production of an immunosuppressive metabolite, GXP. Suppression of HexA expression in mutant bacteria augmented GXP levels in secondary metabolites. This indicates that infection of X. hominickii into the insect host represses HexA expression and upregulates Lrp expression, leading to GXP production. The GXP metabolites inhibit insect immunity, thus protecting the bacteria-nematode complex. Therefore, the suppression of HexA expression in the insect hemocoel is crucial for the bacteria’s transition from a symbiotic to a pathogenic life form.
{"title":"Suppression of a transcriptional regulator, HexA, is essential for triggering the bacterial virulence of the entomopathogen, Xenorhabdus hominickii","authors":"Gahyeon Jin , Ji-Seon Jeong , Il-Hwan Kim , Yonggyun Kim","doi":"10.1016/j.jip.2024.108219","DOIUrl":"10.1016/j.jip.2024.108219","url":null,"abstract":"<div><div>A nematode-symbiotic bacterium, <em>Xenorhabdus hominickii</em>, exhibits two distinct lifestyles. Upon infection of its host nematode into a target insect, <em>X. hominickii</em> is released into the insect hemocoel and becomes pathogenic. This study examines the critical transformation in bacterial life forms concerning the activity of a transcriptional regulator, HexA. When <em>X. hominickii</em> was cultured in tryptic soy broth, <em>HexA</em> was expressed during the stationary phase of bacterial growth. Conversely, <em>HexA</em> was expressed in the early growth stage within the insect host, <em>Spodoptera exigua</em>, when infected with <em>X. hominickii</em>. The transient expression of <em>HexA</em> was succeeded by the expression of another transcriptional regulator, <em>Lrp</em>, which led to the production of bacterial virulent factors. Expression of <em>HexA</em> was manipulated by replacing its promoter with an inducible promoter controlled by the inducer, <span>l</span>-arabinose. In the absence of the inducer, the mutant bacteria expressed <em>HexA</em> at a low level, resulting in a bacterial culture broth that was more effective at suppressing insect immune responses than the wild type. When the inducer was added, <em>HexA</em> was expressed at high levels, rendering the culture broth ineffective in immunosuppression. Interestingly, expression of <em>HexA</em> inhibited the expression of another transcriptional regulator, <em>Lrp</em>, which in turn induced the expression of a non-ribosomal peptide synthetase, <em>gxpS</em>, leading to the production of an immunosuppressive metabolite, GXP. Suppression of <em>HexA</em> expression in mutant bacteria augmented GXP levels in secondary metabolites. This indicates that infection of <em>X. hominickii</em> into the insect host represses <em>HexA</em> expression and upregulates <em>Lrp</em> expression, leading to GXP production. The GXP metabolites inhibit insect immunity, thus protecting the bacteria-nematode complex. Therefore, the suppression of <em>HexA</em> expression in the insect hemocoel is crucial for the bacteria’s transition from a symbiotic to a pathogenic life form.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"207 ","pages":"Article 108219"},"PeriodicalIF":3.6,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142406504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","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.jip.2024.108216
Vince Neil B. Fuertes, Yuho Watanabe, Naoki Itoh
Understanding the factors determining the host ranges of Perkinsus spp., a significant group of pathogenic protozoans affecting shellfish, is essential for preventing their spread and designing effective control measures. Considering that differences in the ability to proliferate within the host may influence the determination of host range, we first injected six Perkinsus spp. into Manila clams Ruditapes philippinarum and monitored the variations of trophozoite numbers. Although all six species were detected in the challenged clams 28 days post infection, the infection intensities varied among species, and particularly two species showed contrasting infection trends: P. mediterraneus showed a decreasing trend of infection, declining to the lowest intensity, whereas that of P. olseni continuously increased, reaching the highest intensity. In vitro exposure to Manila clam hemocytes revealed that the survival of P. mediterraneus trophozoites was suppressed, in contrast to P. olseni, which maintained their viability. Despite similar phagocytic indices for both species, the rate of phagosome acidification was significantly higher for hemocytes phagocytizing P. mediterraneus than those targeting P. olseni. Notably, phagosome acidification was significantly suppressed in hemocytes phagocytizing live P. olseni trophozoites, suggesting that P. olseni may secrete a substance that modulates phagosome acidification, and thereby evades intracellular digestion by the host’s hemocytes. Conversely, P. mediterraneus, with a lower affinity for infecting Manila clams, did not exhibit such modulation. Based on these results, we consider that the ability to modulate phagosome acidification in host hemocytes might be at least one factor in determining the host range of Perkinsus species.
{"title":"Differences in phagosome acidification of Manila clam hemocytes in response to two Perkinsus species with contrasting proliferation dynamics in the host: P. olseni and P. mediterraneus","authors":"Vince Neil B. Fuertes, Yuho Watanabe, Naoki Itoh","doi":"10.1016/j.jip.2024.108216","DOIUrl":"10.1016/j.jip.2024.108216","url":null,"abstract":"<div><div>Understanding the factors determining the host ranges of <em>Perkinsus</em> spp., a significant group of pathogenic protozoans affecting shellfish, is essential for preventing their spread and designing effective control measures. Considering that differences in the ability to proliferate within the host may influence the determination of host range, we first injected six <em>Perkinsus</em> spp. into Manila clams <em>Ruditapes philippinarum</em> and monitored the variations of trophozoite numbers. Although all six species were detected in the challenged clams 28 days post infection, the infection intensities varied among species, and particularly two species showed contrasting infection trends: <em>P. mediterraneus</em> showed a decreasing trend of infection, declining to the lowest intensity, whereas that of <em>P. olseni</em> continuously increased, reaching the highest intensity. <em>In vitro</em> exposure to Manila clam hemocytes revealed that the survival of <em>P. mediterraneus</em> trophozoites was suppressed, in contrast to <em>P. olseni</em>, which maintained their viability. Despite similar phagocytic indices for both species, the rate of phagosome acidification was significantly higher for hemocytes phagocytizing <em>P. mediterraneus</em> than those targeting <em>P. olseni</em>. Notably, phagosome acidification was significantly suppressed in hemocytes phagocytizing live <em>P. olseni</em> trophozoites, suggesting that <em>P. olseni</em> may secrete a substance that modulates phagosome acidification, and thereby evades intracellular digestion by the host’s hemocytes. Conversely, <em>P. mediterraneus</em>, with a lower affinity for infecting Manila clams, did not exhibit such modulation. Based on these results, we consider that the ability to modulate phagosome acidification in host hemocytes might be at least one factor in determining the host range of <em>Perkinsus</em> species.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"207 ","pages":"Article 108216"},"PeriodicalIF":3.6,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142400509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1016/j.jip.2024.108215
M. Shantal Rodríguez-Flores , Ana R. Lopes , Ana Diéguez-Antón , M Carmen Seijo , M. Alice Pinto
Apiaries in Galicia, northwestern Spain, are currently facing the invasive alien species Vespa velutina, which is well established in the region. The pressure on honey bee colonies is high, resulting in both economic and ecological losses. Honey bee colonies also face the challenge of viruses, which are becoming increasingly diverse. In recent years, honey bee viruses have been spreading across taxonomic groups beyond Apoidea, infecting the Vespoidea superfamily. This cross-species spillover has raised concerns in the scientific community due to the potential risk of viruses spreading in ecosystems. Currently, there is a lack of knowledge on this topic, and further research is needed to address this issue. This study employed qPCR and sequencing to investigate the prevalence, loads, and presence of replicative forms of important honey bee viruses in V. velutina individuals collected from 11 apiaries in Galicia. All V. velutina individuals tested positive for DWV, BQCV, AKI complex (ABPV, KBV, and IAPV), or LSV but not for CBPV. DWV showed the highest prevalence (97.0 %) and loads, with both DWV-A (67.4 %) and DWV-B (32.6 %) being detected. The AKI complex (46.3 %) and LSV (43.3 %) were also common, whereas BQCV (11.9 %) was rarer. LSV is detected for the first time in V. velutina. LSV-2 was the dominant strain (82.1 %), and two less frequent (17.9 %) unknown strains were also detected. All 44 screened V. velutina samples carried the replicative form of DWV, and six of these also carried the replicative form of LSV, raising for the first time the possibility of co-infection in the hornet. The detection of honey bee viruses in V. velutina, and the ability of these viruses to spread to other species, may indicate a potential risk of spillover in the apiaries.
{"title":"Honey bee viruses in the yellow-legged hornet Vespa velutina (Lepelieter 1836): Prevalence, loads, and detection of replicative DWV and LSV forms","authors":"M. Shantal Rodríguez-Flores , Ana R. Lopes , Ana Diéguez-Antón , M Carmen Seijo , M. Alice Pinto","doi":"10.1016/j.jip.2024.108215","DOIUrl":"10.1016/j.jip.2024.108215","url":null,"abstract":"<div><div>Apiaries in Galicia, northwestern Spain, are currently facing the invasive alien species <em>Vespa velutina,</em> which is well established in the region. The pressure on honey bee colonies is high, resulting in both economic and ecological losses. Honey bee colonies also face the challenge of viruses, which are becoming increasingly diverse. In recent years, honey bee viruses have been spreading across taxonomic groups beyond Apoidea, infecting the Vespoidea superfamily. This cross-species spillover has raised concerns in the scientific community due to the potential risk of viruses spreading in ecosystems. Currently, there is a lack of knowledge on this topic, and further research is needed to address this issue. This study employed qPCR and sequencing to investigate the prevalence, loads, and presence of replicative forms of important honey bee viruses in <em>V. velutina</em> individuals collected from 11 apiaries in Galicia. All <em>V. velutina</em> individuals tested positive for DWV, BQCV, AKI complex (ABPV, KBV, and IAPV), or LSV but not for CBPV. DWV showed the highest prevalence (97.0 %) and loads, with both DWV-A (67.4 %) and DWV-B (32.6 %) being detected. The AKI complex (46.3 %) and LSV (43.3 %) were also common, whereas BQCV (11.9 %) was rarer. LSV is detected for the first time in <em>V. velutina</em>. LSV-2 was the dominant strain (82.1 %), and two less frequent (17.9 %) unknown strains were also detected. All 44 screened <em>V. velutina</em> samples carried the replicative form of DWV, and six of these also carried the replicative form of LSV, raising for the first time the possibility of co-infection in the hornet. The detection of honey bee viruses in <em>V. velutina</em>, and the ability of these viruses to spread to other species, may indicate a potential risk of spillover in the apiaries.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":"207 ","pages":"Article 108215"},"PeriodicalIF":3.6,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142400510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}