Journal of invertebrate pathology最新文献

{"title":"Molecular and ultrastructural characterization of a novel cryptic species of the Mesomycetozoea clade isolated from Manila clam, Ruditapes philippinarum, on the west coast of Korea","authors":"","doi":"10.1016/j.jip.2024.108202","DOIUrl":"10.1016/j.jip.2024.108202","url":null,"abstract":"<div><div>In the present study, a cryptic species (IchX) was isolated from the hemolymph of the Manila clam, <em>Ruditapes philippinarum</em>, collected from the west coast region of South Korea. Following comprehensive molecular analysis, a partial sequence resembling the small subunit of the ribosomal RNA (SSU rRNA) gene was obtained, indicating that this species belonged to the class Mesomycetozoea, also known as Ichthyosporea. Detailed phylogenetic analyses based on SSU rRNA sequences placed IchX in a distinct clade within the order Dermocystida, class Mesomycetozoea, and showed that IchX is closely related to <em>Ichthyosporea</em> sp. Microscopic examination of <em>in vitro</em> cultured IchX cells revealed life-cycle stages of different sizes, from the endospore to sporangium through vegetative stages. An ameboid-like structure was observed in the early endospore stages as the characteristic feature of zoospores. Ultrastructural analyses using scanning electron microscopy revealed that all endospores and vegetative cell stages are spherical. Transmission electron microscopy revealed characteristic features, including a spindle pole body and membrane-decorated hyaline vesicles, consistent with those previously described in Mesomycetozoea. In addition, a prominent fibrillar structure was observed. Notably, the cell wall of mature IchX sporangia was digested with 2 M NaOH, while that of the endospores was resistant. This is the first report of a novel Mesomycetozoean from the Manila clams. Further taxonomic study of this organism and elucidation of its pathological characteristics are necessary.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142318606","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}

{"title":"Co-infection is linked to infection prevalence and intensity in oysters amidst high environmental and spatial variation","authors":"","doi":"10.1016/j.jip.2024.108201","DOIUrl":"10.1016/j.jip.2024.108201","url":null,"abstract":"<div><div>Co-infecting parasites modify infection outcomes in the wild. However, it is unclear how multiple environmental factors influence co-infection. The Chesapeake Bay metapopulation of the eastern oyster, <em>Crassostrea virginica</em>, provides an opportunity to test the importance of co-infection across heterogeneous environments because multiple parasites infect oysters across a broad salinity gradient. This study leverages Maryland and Virginia oyster monitoring for a large-scale survey of four co-infecting organisms, including two tissue parasites and two shell bio-eroding parasites. We diagnosed infection in 440 oysters across 16 paired harvested and unharvested reefs and tested the importance of co-infecting organisms for each parasite relative to environmental conditions, host traits, and marine spatial management. Microscopic visual methods were used to diagnose prevalence and intensity of tissue infections with <em>Perkinsus marinus</em> (the causative agent of dermo disease) and <em>Haplosporidium nelsoni</em> (the causative agent of MSX disease). Macroscopic visual methods were used to diagnose prevalence and intensity of shell infections with <em>Cliona</em> boring sponges and blister-inducing <em>Polydora</em> worms. For the three oyster parasites that were detected [<em>H. nelsoni</em> infections were absent in all oysters], salinity was the overall strongest predictor, corresponding to bay-wide patterns of parasite prevalence and/or intensity. Despite high environmental and spatial variation, co-infections corresponded to altered prevalence and/or intensity for all three oyster parasites. The correlational patterns suggest that <em>P. marinus</em> acts as a lynchpin in co-infection, as its intensity increased with <em>Cliona</em> sponge prevalence and <em>P. marinus</em> co-infection predicted higher <em>Polydora</em> blister intensity. Oyster shell height, reef habitat, and harvest status also predicted parasite prevalence and intensity, further reflecting the multivariate drivers of infections in this system. Unharvested reefs had greater vertical habitat structure and higher intensities of <em>Cliona</em> sponge infections, but no differences in the prevalence of any of the three parasites. Spatial patterns unexpectedly show that reef-level predictors of parasite patterns were more important than differences between tributaries. This correlational survey provides novel insights through the statistical relationships between the three oyster parasites, environmental conditions, host traits, and human resource management. New and more detailed scenarios are needed to expand disease ecological theory to encompass co-infection in anthropogenically impacted wildlife populations.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142348369","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}

{"title":"Starvation increases susceptibility to bacterial infection and promotes systemic pathogen proliferation in Drosophila melanogaster females","authors":"","doi":"10.1016/j.jip.2024.108209","DOIUrl":"10.1016/j.jip.2024.108209","url":null,"abstract":"<div><div>Defense against pathogens and parasites requires substantial investment of energy and resources on part of the host. This makes the host immune function dependent on availability and accessibility of resources. A resource deprived host is therefore expected to be more susceptible to infections, although empirical results do not always align with this prediction. Limiting host access to resources can additionally impact within-host pathogen numbers, either directly by altering the amount of resources available to the pathogens for proliferation or indirectly by altering the efficiency of the host immune system. We tested for the effects of host starvation (complete deprivation of resources) on susceptibility to bacterial pathogens, and within-host pathogen proliferation, in <em>Drosophila melanogaster</em> females. Our results show that starvation increases post-infection mortality of the host, but in a pathogen-specific manner. This increase in mortality is always accompanied by increased within-host pathogen proliferation. We therefore propose that starvation compromises host resistance to bacterial infections in <em>Drosophila melanogaster</em> females thereby increasing susceptibility to infections.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327026","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}

{"title":"The sandwich feeding assay for use with first instar nymphs of the Asian citrus psyllid, Diaphorina citri confirms the high susceptibility of this life stage to bacterial pesticidal proteins","authors":"","doi":"10.1016/j.jip.2024.108208","DOIUrl":"10.1016/j.jip.2024.108208","url":null,"abstract":"<div><div>Citrus greening or huanglongbing is the most important disease of citrus and threatens citrus production worldwide. As nymphs of <em>Diaphorina citri</em> play a crucial role in the acquisition and transmission of the citrus greening bacterium, suppression of this life stage is particularly important. However, the lack of a tractable feeding assay for use with first instar <em>D. citri</em> nymphs has impeded assessment of the toxicity of bioactives. Of several bacterial pesticidal proteins (BPP) that are toxic to <em>D. citri</em> adults, Mpp51Aa1 and Cry1Ba1, which have LC₅₀ values of 110 and 120 µg/mL respectively in adults, were fed to 1st instar nymphs in a newly developed assay. For this new sandwich feeding assay, parafilm layers containing feeding solution were placed on top of two 35 mm Petri dishes, with a concave surface created on each. Fifty nymphs were transferred to the membrane on one Petri dish, and the second Petri dish placed on the top to create a “sandwich” with the 1st instar nymphs in the middle. Nymphs were fed for four days and the LC₅₀ values for Mpp51Aa1 and Cry1Ba1 were calculated at 6.7 and 41.6 µg/mL respectively. Bioassays with bioengineered plants expressing Cry1Ba1 confirmed that the majority of <em>D. citri</em> mortality occurs during the 1st instar nymph stage, while egg laying adults are much less susceptible. Taken together, these results confirm that 1st instar <em>D. citri</em> nymphs are more susceptible to BPP than adults and demonstrate the utility of the sandwich feeding assay for effective screening of BPPs prior to investment into production of transgenic plants.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323105","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}

{"title":"Entomopathogenic nematodes in insect pest biocontrol: Diversity and function of excretory/secretory proteins","authors":"","doi":"10.1016/j.jip.2024.108205","DOIUrl":"10.1016/j.jip.2024.108205","url":null,"abstract":"<div><div>Entomopathogenic nematodes (EPNs) are obligate parasitic “biopesticides” that play a vital role in pest management. A thorough understanding of their pathogenic mechanisms is essential for promoting their widespread use in agricultural pest control. The pathogenicity of EPNs arises from two key factors: the pathogenicity of their symbiotic bacteria and the nematodes’ intrinsic pathogenic mechanisms. This review concentrates on the latter, offering an exploration of the excretory/secretory products of EPNs, along with their pathogenic mechanisms and key components. Particular attention is given to specific excretory/secretory proteins (ESPs) identified in various EPN species. The aim is to provide a foundational reference for comprehending the role of these ESPs in pest control. Furthermore, the review discusses the potential of these findings to advance the development of eco-friendly biopesticides, thereby supporting sustainable agricultural practices.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307891","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}

{"title":"MaEng1, an endo-1,3-glucanase, contributes to the conidiation pattern shift through changing the cell wall structure in Metarhizium acridum","authors":"","doi":"10.1016/j.jip.2024.108204","DOIUrl":"10.1016/j.jip.2024.108204","url":null,"abstract":"<div><div>Microcycle conidiation has displayed the greater potential than normal conidiation in large-scale production of mycopesticides. Fungi require partial hydrolysis of the cell wall to achieve the necessary plasticity during their morphological changes. Therefore, various cell wall-associated hydrolases are crucial for fungal morphogenesis. Eng1, as an endo-β-1,3-glucanase, is involved in the cell separation of fungi, but its role in morphological changes of entomopathogenic fungi is not yet clear. Here, the endo-β-1,3-glucanase gene <em>MaEng1</em> was characterized in the model entomopathogenic fungi <em>M. acridum</em>. MaEng1 possesses a typical carbohydrate hydrolase domain and belongs to the GH81 family. The functions of <em>MaEng1</em> in fungal growth, stress tolerance, pathogenicity, and conidiation capacity were analyzed using targeted gene disruption. The results displayed that the absence of <em>MaEng1</em> does not affect the fungal growth, stress tolerances, and pathogenicity in <em>M. acridum</em>. However, the knockout of <em>MaEng1</em> led to the normal conidiation of <em>M. acridum</em> on the SYA medium, which can induce the microcycle conidiation. Moreover, the content of β-1,3-glucan in the cell wall of the <em>MaEng1</em>-disruption strain were significantly reduced and the exposures of β-1,3-glucan on the surface of the mature conidia and mycelia in Δ<em>MaEng1</em> were declined, indicating that MaEng1 contributes to the conversion of conidiation mode in <em>M. acridum</em> by affecting the cell wall structure.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307892","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}

{"title":"Comparative genomic analysis of copepod humoral immunity genes with sex-biased expression in Labidocera rotunda","authors":"","doi":"10.1016/j.jip.2024.108198","DOIUrl":"10.1016/j.jip.2024.108198","url":null,"abstract":"<div><div>Studies of innate immune system function in invertebrates have contributed significantly to our understanding of the mammalian innate immune system. However, in-depth research on innate immunity in marine invertebrates remains sparse. We generated the first <em>de novo</em> genome and transcriptome sequences of copepod <em>Labidocera rotunda</em> using Illumina paired-end data and conducted a comparative genome analysis including five crustaceans (four copepods and one branchiopod species). We cataloged the presence of Toll, Imd, JAK/STAT, and JNK pathway components among them and compared them with 17 previously reported diverse arthropod species representative of insects, myriapods, chelicerates, and malacostracans. Our results indicated that copepod Gram-negative binding proteins may function in direct digestion or pathogen killing. The phylogenetic analysis of arthropod TEP and copepod-specific GCGEQ motif patterns suggested that the evolutionary history of copepod TEPs may have diverged from that of other arthropods. We classified the copepod Toll-like receptors identified in our analysis as either vertebrate or protostome types based on their cysteine motifs and the tree built with their Toll/interleukin-1 receptor domains. LrotCrustin, the first copepod AMP, was identified based on the structure of its WAP domain and deep-learning AMP predictors. Gene expression level analysis of <em>L. rotunda</em> innate immunity-related transcripts in each sex showed higher Toll pathway-related expression in male <em>L. rotunda</em> than in females, which may reflect an inverse correlation between allocation of reproductive investment and elevated immune response in males. Taken together, the results of our study provide insight into copepod innate immunity-related gene families and illuminate the evolutionary potential of copepods relative to other crustaceans.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307890","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}

{"title":"Prevalence and population genetic analyses of parasites in invasive Vespa velutina and native Hymenoptera","authors":"","doi":"10.1016/j.jip.2024.108203","DOIUrl":"10.1016/j.jip.2024.108203","url":null,"abstract":"<div><div>Invasive species pose a threat to the ecological balance of the ecosystems they invade by altering local host-pathogen dynamics. To investigate these relationships and their potential consequences, we examined the prevalence and genetic diversity patterns of Trypanosomatidae, Lipotrophidae, and Nosematidae in a collection of sympatric isolates of the invasive hornet <em>Vespa velutina</em> and local Hymenoptera from two recently colonized areas: Europe and South Korea. Data were gathered through PCR amplification and massive parallel sequencing, and analyses were conducted using population genetics tools. Parasite prevalences showed substantial variation depending on (i) the parasite family (Trypanosomatidae and Nosematidae were the most and less prevalent, respectively), (ii) location (e.g. Galicia displayed the highest pooled values), (iii) the season (highest in spring for Trypanosomatidae and Lipotrophidae), and (iv) the host. <em>V. velutina</em> exhibited significantly lower parasite occurrence than native Hymenoptera across all parasite families (consistent with the enemy release hypothesis), although this difference was less pronounced during the periods of heightened predatory activity, suggestive of trophic transmission. Parasite species displayed significant genetic differentiation between European and South Korean isolates, yet no differentiation was observed across hosts, suggesting that all Hymenoptera are exposed to a common local pathogen population. There was no indication that <em>V. velutina</em> acted as a carrier of foreign parasites to the invaded territories.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307893","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}

{"title":"A novel fungal sensor (Ngs1) of N-acetylglucosamine (GlcNAc) mediates the fungal response to GlcNAc in the interaction between entomopathogenic Beauveria bassiana and insect host","authors":"","doi":"10.1016/j.jip.2024.108206","DOIUrl":"10.1016/j.jip.2024.108206","url":null,"abstract":"<div><div>As <em>N</em>-acetylglucosamine (GlcNAc) ubiquitously exists in both insect cuticle and fungal cell walls, the GlcNAc sensor (Ngs1) potentially plays important roles in the interactions between entomopathogenic fungi and their insect hosts. However, the roles of the Ngs1 derived from the entomopathogens in response to the host’s cuticle remain completely unexplored. In this study, a putative Ngs1 homolog was identified in the entomopathogenic fungus <em>Beauveria bassiana</em>. Deletion of <em>Ngs1</em> significantly reduced virulence towards <em>Galleria mellonella</em> larvae either through cuticle infection (by 23%) or by bypassing the cuticle (by 44%). To investigate the role of <em>Ngs1</em> in fungal virulence, an analysis of the transcriptome induced by <em>Locusta migratoria</em> exoskeleton was conducted, highlighting the regulatory mechanism of <em>Ngs1</em> in carbohydrate metabolic process, particularly chitin metabolism and GlcNAc metabolism. Consistent with the transcriptomic data, <em>Ngs1</em>-deletion mutants showed reduced activities of both secreted chitinase (17% reduction) and Pr1 protease (35% reduction). Loss of <em>Ngs1</em> down-regulated the transcript levels of GlcNAc-catabolism genes, resulting in a 17% decrease in fungal growth on GlcNAc-supported media. Furthermore, <em>Ngs1</em> deficiency attenuated the fungal response to GlcNAc, leading to the alteration of fungal resistance to diverse stress cues. All of these changes contribute to the reduction in virulence in <em>Ngs1</em>-deficient <em>B. bassiana</em>. These findings support that Ngs1 plays a critical role in responding to insect-derived GlcNAc, affecting the production of cuticle-degrading enzymes to penetrate insect epidermis, GlcNAc-induced changes of stress resistance, and contribute to the fungal virulence against insects.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142289348","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}

{"title":"Representative honey bee viruses do not replicate in the small hive beetle, Aethina tumida Murray","authors":"","doi":"10.1016/j.jip.2024.108207","DOIUrl":"10.1016/j.jip.2024.108207","url":null,"abstract":"<div><div>The small hive beetle (SHB), <em>Aethina tumida</em> Murray, is an invasive pest of the honey bee and causes significant damage through the consumption of colony resources and brood. Two assumptions related to honey bee virus transmission have been made about SHB: first, that SHB vectors honey bee viruses and second, that these viruses replicate in SHB based on the detection of both positive and negative strand viral genomic RNA within SHB. To clarify the role of SHB in virus transmission, we sought to address whether selected honey bee viruses replicate in SHB. Sequences derived from five honey bee viruses were identified in the transcriptomes of field-caught SHB from the U.S., but not in those of lab-reared SHB, suggesting that these viruses do not replicate in SHB. To elucidate whether the representative viruses, <em>Israeli acute paralysis virus</em> (IAPV; <em>Dicistroviridae</em>) and <em>Deformed wing virus</em> (DWV; <em>Iflaviridae</em>) replicate in SHB, we tested for replication <em>in vitro</em> in an SHB-derived cell line (BCIRL-AtumEN-1129-D6). Following treatment of the cell line with viral particles or viral RNA, the number of virus genomes was monitored by reverse transcription quantitative PCR (RT-qPCR). In contrast to the positive control, IAPV and DWV RNA levels steadily decreased over a period of 8 days. Collectively, these results from bioinformatic observations and <em>in vitro</em> experiments indicate that IAPV and DWV do not replicate in SHB. These results are consistent with the host specificity of most insect viruses within a single insect order and indicate that while SHB may serve as a mechanical vector of honey bee viruses within and between hives, this insect does not serve as a biological vector for these honey bee viruses.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142289349","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}