Pub Date : 2024-11-01DOI: 10.1016/j.jip.2024.108221
Silk is an economically and culturally important product of Thailand that is threatened by the outbreaks of the Bombyx mori nucleopolyhedrovirus (BmNPV) in silkworm rearings. BmNPV infects the larval stages of the silkworm Bombyx mori, causing fatal viral infection and preventing the larvae from reaching the pupal stage. Numerous BmNPV isolates have been described from silk-producing countries from all over the world. In this study, the geographic distribution of BmNPV in Thailand was analyzed by collecting 18 samples from different regions. The BmNPV samples were analyzed by PCR and whole genome sequencing was performed for eight specimens. Their genome size ranged from 125,888 bp to 126,783 bp, comprising 138 open reading frames. Although the sequenced BmNPV genomes could be phylogenetically differentiated, no correlation between geographic and genetic distance was observed, indicating a close relationship between the BmNPV from Thailand.
{"title":"Distribution and genetic diversity of Bombyx mori nucleopolyhedrovirus in mass-reared silkworms in Thailand","authors":"","doi":"10.1016/j.jip.2024.108221","DOIUrl":"10.1016/j.jip.2024.108221","url":null,"abstract":"<div><div>Silk is an economically and culturally important product of Thailand that is threatened by the outbreaks of the Bombyx mori nucleopolyhedrovirus (BmNPV) in silkworm rearings. BmNPV infects the larval stages of the silkworm <em>Bombyx mori</em>, causing fatal viral infection and preventing the larvae from reaching the pupal stage. Numerous BmNPV isolates have been described from silk-producing countries from all over the world. In this study, the geographic distribution of BmNPV in Thailand was analyzed by collecting 18 samples from different regions. The BmNPV samples were analyzed by PCR and whole genome sequencing was performed for eight specimens. Their genome size ranged from 125,888 bp to 126,783 bp, comprising 138 open reading frames. Although the sequenced BmNPV genomes could be phylogenetically differentiated, no correlation between geographic and genetic distance was observed, indicating a close relationship between the BmNPV from Thailand.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142467750","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 : 2024-11-01DOI: 10.1016/j.jip.2024.108228
Translucent post-larva vibriosis (VTPD) in Penaeus vannamei, caused by the virulence factor Vibrio high virulent protein 2 (vhvp-2) gene, poses a significant threat to the shrimp aquaculture industry in China. This study conducted a comprehensive analysis of the vhvp-2 gene distribution and genetic diversity among Vibrio, which play a key role in the pathogenesis of translucent post-larvae disease (TPD). A total of 6281 Vibrio genomes from the NCBI database were screened, revealing the presence of the vhvp-2 gene in 26 strains, predominantly in V. parahaemolyticus, with diverse locations on both plasmids and chromosomes. Comparative analysis of the genomes, plasmids, and the vhvp-2 gene successfully differentiated three distinct clusters of Vibrio species and identified at least two major plasmid groups. However, these plasmid groups did not exhibit the same evolutionary relationships as the host bacteria themselves. The analysis also revealed the conserved presence of the vhvp-2 gene along with genetic variations. Moreover, the widespread presence of antimicrobial resistance genes (ARGs) and virulence factors in Vibrio strains enhances their pathogenicity and poses increased public health risks. The findings underscore the importance of understanding the adaptability, evolution, and ecological characteristics of Vibrio strains harboring vhvp-2 gene. This research provides a scientific foundation for the development of effective disease prevention and control strategies, contributing to the mitigation of TPD’s impact on the shrimp aquaculture industry and supporting its sustainable and healthy growth.
{"title":"Characteristics of vhvp-2 gene distribution and diversity within the Vibrio causing translucent post-larvae disease (TPD)","authors":"","doi":"10.1016/j.jip.2024.108228","DOIUrl":"10.1016/j.jip.2024.108228","url":null,"abstract":"<div><div>Translucent post-larva vibriosis (<em>V</em><sub>TPD</sub>) in <em>Penaeus vannamei</em>, caused by the virulence factor <em>Vibrio</em> high virulent protein 2 (<em>vhvp-2</em>) gene, poses a significant threat to the shrimp aquaculture industry in China. This study conducted a comprehensive analysis of the <em>vhvp-2</em> gene distribution and genetic diversity among <em>Vibrio</em>, which play a key role in the pathogenesis of translucent post-larvae disease (TPD). A total of 6281 <em>Vibrio</em> genomes from the NCBI database were screened, revealing the presence of the <em>vhvp-2</em> gene in 26 strains, predominantly in <em>V. parahaemolyticus</em>, with diverse locations on both plasmids and chromosomes. Comparative analysis of the genomes, plasmids, and the <em>vhvp-2</em> gene successfully differentiated three distinct clusters of <em>Vibrio</em> species and identified at least two major plasmid groups. However, these plasmid groups did not exhibit the same evolutionary relationships as the host bacteria themselves. The analysis also revealed the conserved presence of the <em>vhvp-2</em> gene along with genetic variations. Moreover, the widespread presence of antimicrobial resistance genes (ARGs) and virulence factors in <em>Vibrio</em> strains enhances their pathogenicity and poses increased public health risks. The findings underscore the importance of understanding the adaptability, evolution, and ecological characteristics of <em>Vibrio</em> strains harboring <em>vhvp-2</em> gene. This research provides a scientific foundation for the development of effective disease prevention and control strategies, contributing to the mitigation of TPD’s impact on the shrimp aquaculture industry and supporting its sustainable and healthy growth.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142568930","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 : 2024-11-01DOI: 10.1016/j.jip.2024.108227
The use of herbicides and their long persistence in the environment have raised concerns about potential harm to ecosystems and human health. However, there is a gap in the knowledge regarding the effects of continuous exposure to residues or admitted field doses on non-target organisms such as insects that inhabit croplands and play key ecological roles. Furthermore, the potential impact of this exposure on host-pathogen interactions remains largely unstudied. This study adopted an eco-immunological perspective, investigating the influence of herbicides on an organism’s interaction with natural pathogens. The impact of this combination of multiple stressors was studied in larvae of the red flour beetle, Tribolium castaneum Herbst, 1797, previously treated with a pendimethalin-based commercial formulation (PND) and exposed to the natural entomopathogen Bacillus thuringiensis (1x109, 1x1010 cells/mL). The effects of three PND concentrations (i.e. a recommended field rate, a soil contaminant concentration and the maximum residue limit admitted in grain in EU countries: 4L/ha, 13 and 0.05 ppm, respectively) on life history traits such as developmental time, pupation rate and survival rate and the expression levels of antimicrobial peptides (AMPs) were assessed. The results showed that even at doses considered safe for human consumption or field application, exposure to PND had an impact on beetle larvae, affecting their vulnerability to B. thuringiensis. The combined experience of exposure to PND and B. thuringiensis at the larval stage resulted in a delay of larval development, a reduction in the number of pupae and emerging adults, and alterations in their body condition. Moreover, changes in the expression levels of the analysed AMPs, including Attacin 1, Defensin 2 and Coleoptericin 2, were recorded as markers for immune activity against the bacterium. The findings of this study highlight the general need for further studies on the effects of commonly used herbicides on the physiology of non-target organisms and on host-pathogen interactions at the community level. Additionally, there is a need for the establishment of revised residual levels that are deemed non-toxic to soil organisms and humans.
{"title":"The combined effect of herbicide and Bacillus thuringiensis exposure delays development in the red flour beetle","authors":"","doi":"10.1016/j.jip.2024.108227","DOIUrl":"10.1016/j.jip.2024.108227","url":null,"abstract":"<div><div>The use of herbicides and their long persistence in the environment have raised concerns about potential harm to ecosystems and human health. However, there is a gap in the knowledge regarding the effects of continuous exposure to residues or admitted field doses on non-target organisms such as insects that inhabit croplands and play key ecological roles. Furthermore, the potential impact of this exposure on host-pathogen interactions remains largely unstudied. This study adopted an eco-immunological perspective, investigating the influence of herbicides on an organism’s interaction with natural pathogens. The impact of this combination of multiple stressors was studied in larvae of the red flour beetle, <em>Tribolium castaneum</em> Herbst, 1797, previously treated with a pendimethalin-based commercial formulation (PND) and exposed to the natural entomopathogen <em>Bacillus thuringiensis</em> (1x10<sup>9</sup>, 1x10<sup>10</sup> cells/mL)<em>.</em> The effects of three PND concentrations (i.e. a recommended field rate, a soil contaminant concentration and the maximum residue limit admitted in grain in EU countries: 4L/ha, 13 and 0.05 ppm, respectively) on life history traits such as developmental time, pupation rate and survival rate and the expression levels of antimicrobial peptides (AMPs) were assessed. The results showed that even at doses considered safe for human consumption or field application, exposure to PND had an impact on beetle larvae, affecting their vulnerability to <em>B. thuringiensis</em>. The combined experience of exposure to PND and <em>B. thuringiensis</em> at the larval stage resulted in a delay of larval development, a reduction in the number of pupae and emerging adults, and alterations in their body condition. Moreover, changes in the expression levels of the analysed AMPs, including Attacin 1, Defensin 2 and Coleoptericin 2, were recorded as markers for immune activity against the bacterium. The findings of this study highlight the general need for further studies on the effects of commonly used herbicides on the physiology of non-target organisms and on host-pathogen interactions at the community level. Additionally, there is a need for the establishment of revised residual levels that are deemed non-toxic to soil organisms and humans.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142545942","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 : 2024-10-24DOI: 10.1016/j.jip.2024.108224
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":"","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":null,"pages":null},"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 : 2024-10-24DOI: 10.1016/j.jip.2024.108223
Cristian Montalva, Cristian González, Cecilia Ruiz, Isabel Vives, Andrea Díaz, Luis Devotto, Juscelino Rodrigues, Luiz F N Rocha, Javiera Manríquez, Tania Vásquez, Richard A Humber, Christian Luz
Drosophila suzukii is an invasive pest of berries and other soft-skinned fruits, was first detected in Chile in 2017, and has since spread over 2,800 km from north to south. Sustainable control of the spotted-wing drosophila (SWD) is essential due the negative attitude of the consumers toward the excessive use of insecticides. During a survey in Chile for biological control agents, thirty-two isolates of entomopathogenic fungi (EPF) were isolated from mycotized insects and soil samples, identified through sequence analysis, and tested against D. suzukii adults under laboratory conditions. The EPF identified are Akanthomyces muscarius, Beauveria bassiana, Beauveria pseudobassiana, Clonostachys rosea, Metarhizium alvesii, Metarhizium brunneum and Metarhizium robertsii. Six isolates caused 100 % of mortality of D. suzukii adults within ten days after the initial exposition to conidia; these included four B. bassiana isolates (LSB 110, LSB 114, LSB 122 and LSB 125), one M. robertsii isolate (LSB 115) and one M. brunneum isolate (LSB 127). LSB 122 and LSB 125 induced the shortest lethal time (LT50 4 and 4.2 days, respectively), while Akanthomyces and Clonostachys caused ≤ 36 % cumulative mortality of the adults at 10 days of exposure. These results indicate that isolates of B. bassiana, M. robertsii and M. brunneum have significant potential as microbial control agents against D. suzukii adults. This study marks a critical step forward in identifying and validating native entomopathogenic fungi in Chile for sustainable pest management. Future work will focus on further testing these isolates under laboratory, semi-field and field conditions to optimize their application in real-world agricultural settings.
{"title":"Isolation and identification of native Chilean entomopathogenic fungi and their potential for the control of Drosophila suzukii.","authors":"Cristian Montalva, Cristian González, Cecilia Ruiz, Isabel Vives, Andrea Díaz, Luis Devotto, Juscelino Rodrigues, Luiz F N Rocha, Javiera Manríquez, Tania Vásquez, Richard A Humber, Christian Luz","doi":"10.1016/j.jip.2024.108223","DOIUrl":"10.1016/j.jip.2024.108223","url":null,"abstract":"<p><p>Drosophila suzukii is an invasive pest of berries and other soft-skinned fruits, was first detected in Chile in 2017, and has since spread over 2,800 km from north to south. Sustainable control of the spotted-wing drosophila (SWD) is essential due the negative attitude of the consumers toward the excessive use of insecticides. During a survey in Chile for biological control agents, thirty-two isolates of entomopathogenic fungi (EPF) were isolated from mycotized insects and soil samples, identified through sequence analysis, and tested against D. suzukii adults under laboratory conditions. The EPF identified are Akanthomyces muscarius, Beauveria bassiana, Beauveria pseudobassiana, Clonostachys rosea, Metarhizium alvesii, Metarhizium brunneum and Metarhizium robertsii. Six isolates caused 100 % of mortality of D. suzukii adults within ten days after the initial exposition to conidia; these included four B. bassiana isolates (LSB 110, LSB 114, LSB 122 and LSB 125), one M. robertsii isolate (LSB 115) and one M. brunneum isolate (LSB 127). LSB 122 and LSB 125 induced the shortest lethal time (LT<sub>50</sub> 4 and 4.2 days, respectively), while Akanthomyces and Clonostachys caused ≤ 36 % cumulative mortality of the adults at 10 days of exposure. These results indicate that isolates of B. bassiana, M. robertsii and M. brunneum have significant potential as microbial control agents against D. suzukii adults. This study marks a critical step forward in identifying and validating native entomopathogenic fungi in Chile for sustainable pest management. Future work will focus on further testing these isolates under laboratory, semi-field and field conditions to optimize their application in real-world agricultural settings.</p>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142502199","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 : 2024-10-23DOI: 10.1016/j.jip.2024.108225
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":"","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":null,"pages":null},"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}
Pub Date : 2024-10-22DOI: 10.1016/j.jip.2024.108226
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":"","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":null,"pages":null},"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
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":"","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":null,"pages":null},"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
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":"","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":null,"pages":null},"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
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":"","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":null,"pages":null},"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}
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