Pub Date : 2024-10-10DOI: 10.1016/j.jip.2024.108218
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":"","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":null,"pages":null},"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
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":"","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":null,"pages":null},"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
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":"","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":null,"pages":null},"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
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":"","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":null,"pages":null},"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}
Pub Date : 2024-10-05DOI: 10.1016/j.jip.2024.108200
As primary producers, plants play a central role in mediating interactions across trophic levels. Although plants are the primary food source for herbivorous insects, they can protect themselves from herbivore damage. Many plants produce toxic compounds that directly reduce herbivore feeding, but plants also protect themselves indirectly by attracting natural enemies of the attacking herbivore through volatile signaling. These so-called tri-trophic interactions have historically been documented aboveground in aerial plant parts but are also known to occur belowground in root systems. In addition to herbivores, plants directly interact with other organisms, which can influence the outcomes of tri-trophic interactions. Arbuscular mycorrhizal fungi (AMF) are symbiotic soil microbes that colonize the roots of plants and facilitate nutrient uptake. These microbes can alter plant chemistry and subsequent resistance to herbivores. Few studies, however, have shown how AMF affect tri-trophic interactions above- or belowground. This study examines how AMF colonization affects the emission of root volatiles when plants are under attack by western corn rootworm, a problematic pest of corn, and subsequent attraction of entomopathogenic nematodes, a natural enemy of western corn rootworm. Mycorrhizal fungi increased rootworm survival but decreased larval weight. Differences were detected across root volatile profiles, but there was not a clear link between volatile signaling and nematode behavior. Nematodes were more attracted to non-mycorrhizal plants without rootworms and AMF alone in soil, suggesting that AMF may interfere with cues that are used in combination with volatiles which nematodes use to locate prey.
{"title":"Arbuscular mycorrhizal fungi influence belowground interactions between a specialist root-feeder and its natural enemy","authors":"","doi":"10.1016/j.jip.2024.108200","DOIUrl":"10.1016/j.jip.2024.108200","url":null,"abstract":"<div><div>As primary producers, plants play a central role in mediating interactions across trophic levels. Although plants are the primary food source for herbivorous insects, they can protect themselves from herbivore damage. Many plants produce toxic compounds that directly reduce herbivore feeding, but plants also protect themselves indirectly by attracting natural enemies of the attacking herbivore through volatile signaling. These so-called tri-trophic interactions have historically been documented aboveground in aerial plant parts but are also known to occur belowground in root systems. In addition to herbivores, plants directly interact with other organisms, which can influence the outcomes of tri-trophic interactions. Arbuscular mycorrhizal fungi (AMF) are symbiotic soil microbes that colonize the roots of plants and facilitate nutrient uptake. These microbes can alter plant chemistry and subsequent resistance to herbivores. Few studies, however, have shown how AMF affect tri-trophic interactions above- or belowground. This study examines how AMF colonization affects the emission of root volatiles when plants are under attack by western corn rootworm, a problematic pest of corn, and subsequent attraction of entomopathogenic nematodes, a natural enemy of western corn rootworm. Mycorrhizal fungi increased rootworm survival but decreased larval weight. Differences were detected across root volatile profiles, but there was not a clear link between volatile signaling and nematode behavior. Nematodes were more attracted to non-mycorrhizal plants without rootworms and AMF alone in soil, suggesting that AMF may interfere with cues that are used in combination with volatiles which nematodes use to locate prey.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142391122","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 : 2024-10-02DOI: 10.1016/j.jip.2024.108214
Beauveria bassiana (B. bassiana) is a common fungal disease in sericulture. Previous research has primarily focused on investigating genes involved in innate immunity. However, the response of Bombyx mori (B. mori) to B. bassiana requires the coordination of other biological processes in addition to the immune system. We measured protein expression profile of B. mori after inoculating B. bassiana using iTRAQ technology in previous. Here we constructed a co-expression protein–protein interaction network of B. mori in response to B. bassiana infection. Subnetworks and modules were analyzed, and the functions of these modules were annotated. The results revealed the identification of numerous proteins associated with cellular immunity, including those involved in phagosomes, lysosomes, mTOR signaling, sugar metabolism, and the ubiquitin–proteasome pathway. Meanwhile, we observed that the pathways involved in protein synthesis were activated, including pyruvate and purine metabolism, RNA transport, ribosome, protein processing in endoplasmic reticulum, and protein export pathways, during B. bassiana infection. Based on this analysis, we selected six candidate genes (shock protein, ribosome, translocon, actin muscle-type A2, peptidoglycan recognition protein, and collagenase) that were found to be related to the response to B. bassiana. Further verification experiments demonstrated significant changes in their expression levels after inoculation with B. bassiana. These research findings provide new insights into the molecular mechanism of insect immune response to fungal infection.
Beauveria bassiana（B. bassiana）是一种常见的养蚕真菌疾病。以往的研究主要集中于研究先天免疫相关基因。然而，桑蚕（Bombyx mori）对 B. bassiana 的反应除了需要免疫系统外，还需要其他生物过程的协调。以前我们曾利用 iTRAQ 技术测量了 B. mori 接种 B. bassiana 后的蛋白质表达谱。在此，我们构建了森蝽在应对 B. bassiana 感染时的共表达蛋白-蛋白相互作用网络。我们分析了子网络和模块，并对这些模块的功能进行了注释。结果发现了许多与细胞免疫相关的蛋白质，包括参与吞噬体、溶酶体、mTOR 信号转导、糖代谢和泛素-蛋白酶体通路的蛋白质。同时，我们观察到，在 B. bassiana 感染期间，参与蛋白质合成的途径被激活，包括丙酮酸和嘌呤代谢、RNA 转运、核糖体、内质网蛋白质加工和蛋白质输出途径。根据这一分析，我们选出了六个候选基因（休克蛋白、核糖体、转座子、肌动蛋白 A2 型、肽聚糖识别蛋白和胶原酶），发现它们与 B. bassiana 的反应有关。进一步的验证实验表明，接种 B. bassiana 后，它们的表达水平发生了显著变化。这些研究成果为昆虫对真菌感染的免疫反应分子机制提供了新的见解。
{"title":"Identification of function modules in the co-expression protein–protein interaction network of Bombyx mori in response to Beauveria bassiana infection","authors":"","doi":"10.1016/j.jip.2024.108214","DOIUrl":"10.1016/j.jip.2024.108214","url":null,"abstract":"<div><div><em>Beauveria bassiana</em> (<em>B. bassiana</em>) is a common fungal disease in sericulture. Previous research has primarily focused on investigating genes involved in innate immunity. However, the response of <em>Bombyx mori</em> (<em>B. mori</em>) to <em>B. bassiana</em> requires the coordination of other biological processes in addition to the immune system. We measured protein expression profile of <em>B. mori</em> after inoculating <em>B. bassiana</em> using iTRAQ technology in previous. Here we constructed a co-expression protein–protein interaction network of <em>B. mori</em> in response to <em>B. bassiana</em> infection. Subnetworks and modules were analyzed, and the functions of these modules were annotated. The results revealed the identification of numerous proteins associated with cellular immunity, including those involved in phagosomes, lysosomes, mTOR signaling, sugar metabolism, and the ubiquitin–proteasome pathway. Meanwhile, we observed that the pathways involved in protein synthesis were activated, including pyruvate and purine metabolism, RNA transport, ribosome, protein processing in endoplasmic reticulum, and protein export pathways, during <em>B. bassiana</em> infection. Based on this analysis, we selected six candidate genes (shock protein, ribosome, translocon, actin muscle-type A2, peptidoglycan recognition protein, and collagenase) that were found to be related to the response to <em>B. bassiana</em>. Further verification experiments demonstrated significant changes in their expression levels after inoculation with <em>B. bassiana</em>. These research findings provide new insights into the molecular mechanism of insect immune response to fungal infection.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142375571","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 : 2024-09-28DOI: 10.1016/j.jip.2024.108213
Entomopathogenic Xenorhabdus spp. bacteria, symbiont of the nematode Steinernema spp., shows potential for mitigating agricultural pests and diseases through bioactive compound production. The plant-parasitic nematode (PPN) Meloidogyne incognita affects the yield and quality of numerous crops, causing significant economic losses. We speculate that Cell-Free Supernatants (CFS) from Xenorhabdus spp. could reduce the impact of the root-knot nematode (RKN) M. incognita without negatively affecting entomopathogenic nematodes (EPNs), which are considered beneficial organisms. This study explored the activity of seven CFS against M. incognita (two populations, AL05 and Chipiona) and their possible effects on EPNs. The in vitro impact of CFS at 10 %, 40 %, and 90 % concentrations on nematode motility at four and 24 h were tested on the PPN M. incognita and two EPNs, S. feltiae and H. bacteriophora. Additionally, EPN viability and virulence were evaluated at two and five days. On the other hand, tomato plant-mesocosm experiments examined the activity of four CFS on M. incognita reproductive capacity and EPN virulence. In vitro exposure of M. incognita to 90 % concentration of CFS resulted in reductions of activity over 60 % after four hours of expossure in four out of seven CFS. In the in vitro evaluation of two species of EPNs, none of the CFS affected the activity across any tested doses after four hours of exposure nor after 24 h. Plant-mesocosm experiments showed that CFS application significantly reduced RKN galls, egg masses, and galling index. However, the virulence of both EPN species decreased 15 days after application, with a significant impact on S. feltiae. Overall, these findings suggest that CFS could be used as a bio-tool against M. incognita in tomato crops, mitigating its impact on plant growth. However, this study also highlights the necessity of investigating the effects of CFS on non-target organisms.
{"title":"Direct effects of Xenorhabdus spp. cell-free supernatant on Meloidogyne incognita in tomato plants and its impact on entomopathogenic nematodes","authors":"","doi":"10.1016/j.jip.2024.108213","DOIUrl":"10.1016/j.jip.2024.108213","url":null,"abstract":"<div><div>Entomopathogenic <em>Xenorhabdus</em> spp. bacteria, symbiont of the nematode <em>Steinernema</em> spp., shows potential for mitigating agricultural pests and diseases through bioactive compound production. The plant-parasitic nematode (PPN) <em>Meloidogyne incognita</em> affects the yield and quality of numerous crops, causing significant economic losses. We speculate that Cell-Free Supernatants (CFS) from <em>Xenorhabdus</em> spp. could reduce the impact of the root-knot nematode (RKN) <em>M. incognita</em> without negatively affecting entomopathogenic nematodes (EPNs), which are considered beneficial organisms. This study explored the activity of seven CFS against <em>M. incognita</em> (two populations, AL05 and Chipiona) and their possible effects on EPNs. The <em>in vitro</em> impact of CFS at 10 %, 40 %, and 90 % concentrations on nematode motility at four and 24 h were tested on the PPN <em>M. incognita</em> and two EPNs, <em>S. feltiae</em> and <em>H. bacteriophora.</em> Additionally, EPN viability and virulence were evaluated at two and five days. On the other hand, tomato plant-mesocosm experiments examined the activity of four CFS on <em>M. incognita</em> reproductive capacity and EPN virulence. <em>In vitro</em> exposure of <em>M. incognita</em> to 90 % concentration of CFS resulted in reductions of activity over 60 % after four hours of expossure in four out of seven CFS. In the <em>in vitro</em> evaluation of two species of EPNs, none of the CFS affected the activity across any tested doses after four hours of exposure nor after 24 h. Plant-mesocosm experiments showed that CFS application significantly reduced RKN galls, egg masses, and galling index. However, the virulence of both EPN species decreased 15 days after application, with a significant impact on <em>S. feltiae</em>. Overall, these findings suggest that CFS could be used as a bio-tool against <em>M. incognita</em> in tomato crops, mitigating its impact on plant growth. However, this study also highlights the necessity of investigating the effects of CFS on non-target organisms.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142348367","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 : 2024-09-27DOI: 10.1016/j.jip.2024.108211
Acanthocephalan parasites, specifically from the genus Profilicollis, are known to infect decapod crustaceans, including mole crabs like Emerita brasiliensis, which serve as intermediate hosts in their complex life cycles. This study reports the first occurrence of the acanthocephalan parasite Profilicollis altmani infecting the mole crab Emerita brasiliensis on a sandy beach in southeastern Brazil, thereby expanding the known geographic range of this parasite. Additionally, the study provides novel molecular data that enhance our understanding of the parasite’s taxonomy and distribution, including the first evidence of genetic variation within populations of the intermediate host E. brasiliensis. Phylogenetic analysis based on mitochondrial COX1 gene sequences confirmed the identification of the parasite and underlined small genetic differences among P. altmani populations. These findings suggest a weak genetic population structure of the parasite and underscore the need for further studies to understand gene flow among these populations. This work contributes to the knowledge of parasite-host interactions in sandy beach ecosystems. It highlights the importance of monitoring parasitic infections in species like E. brasiliensis, which play a crucial ecological role in these environments.
据了解，棘头蚴寄生虫，特别是Profilicollis属的棘头蚴寄生虫，会感染十足目甲壳类动物，包括巴西雌鲎等鼹形蟹，这些鼹形蟹是棘头蚴寄生虫复杂生命周期中的中间宿主。本研究报告了巴西东南部沙滩上首次出现的棘头蚴寄生虫Profilicollis altmani感染鼹蟹Emerita brasiliensis的情况，从而扩大了这种寄生虫的已知地理范围。此外，该研究还提供了新的分子数据，加深了我们对该寄生虫的分类和分布的了解，包括首次证明中间宿主巴西鲎（E. brasiliensis）种群内的遗传变异。基于线粒体 COX1 基因序列的系统发育分析证实了寄生虫的身份，并强调了 P. altmani 种群之间的微小遗传差异。这些发现表明寄生虫的遗传种群结构较弱，并强调有必要开展进一步研究，以了解这些种群之间的基因流动情况。这项研究有助于了解沙滩生态系统中寄生虫与宿主之间的相互作用。它强调了监测巴西鳗等物种寄生虫感染的重要性，这些物种在这些环境中发挥着至关重要的生态作用。
{"title":"Acanthocephalan Profilicollis altmani infecting the mole crab Emerita brasiliensis in southeastern Brazil","authors":"","doi":"10.1016/j.jip.2024.108211","DOIUrl":"10.1016/j.jip.2024.108211","url":null,"abstract":"<div><div>Acanthocephalan parasites, specifically from the genus <em>Profilicollis</em>, are known to infect decapod crustaceans, including mole crabs like <em>Emerita brasiliensis</em>, which serve as intermediate hosts in their complex life cycles. This study reports the first occurrence of the acanthocephalan parasite <em>Profilicollis altmani</em> infecting the mole crab <em>Emerita brasiliensis</em> on a sandy beach in southeastern Brazil, thereby expanding the known geographic range of this parasite. Additionally, the study provides novel molecular data that enhance our understanding of the parasite’s taxonomy and distribution, including the first evidence of genetic variation within populations of the intermediate host <em>E. brasiliensis</em>. Phylogenetic analysis based on mitochondrial COX1 gene sequences confirmed the identification of the parasite and underlined small genetic differences among <em>P. altmani</em> populations. These findings suggest a weak genetic population structure of the parasite and underscore the need for further studies to understand gene flow among these populations. This work contributes to the knowledge of parasite-host interactions in sandy beach ecosystems. It highlights the importance of monitoring parasitic infections in species like <em>E. brasiliensis</em>, which play a crucial ecological role in these environments.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142348365","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 : 2024-09-27DOI: 10.1016/j.jip.2024.108212
DIV1 has the characteristics of fast transmission and a broad host range. Its infection leads to a high mortality rate, posing a serious threat to the global crustacean aquaculture industry. In order to increase the accuracy of DIV1 detection and reduce the difficulty of result interpretation, this study modified the original nested PCR method targeting the DIV1 ATPase gene. The internal primers for the nested PCR were redesigned to produce a 338 bp amplification product in the second step PCR, effectively distinguishing the target band from primer dimers. The newly established nested PCR method exhibits strong specificity and high sensitivity, with a detection limit as low as 1.37 × 101 copies/reaction. The developed nested PCR assay provides new technical support for the accurate detection of DIV1 in global crustacean aquaculture.
{"title":"Optimizing the nested PCR method for Decapod iridescent virus 1 (DIV1) targeting ATPase gene by reselecting the inner primers","authors":"","doi":"10.1016/j.jip.2024.108212","DOIUrl":"10.1016/j.jip.2024.108212","url":null,"abstract":"<div><div>DIV1 has the characteristics of fast transmission and a broad host range. Its infection leads to a high mortality rate, posing a serious threat to the global crustacean aquaculture industry. In order to increase the accuracy of DIV1 detection and reduce the difficulty of result interpretation, this study modified the original nested PCR method targeting the DIV1 ATPase gene. The internal primers for the nested PCR were redesigned to produce a 338 bp amplification product in the second step PCR, effectively distinguishing the target band from primer dimers. The newly established nested PCR method exhibits strong specificity and high sensitivity, with a detection limit as low as 1.37 × 10<sup>1</sup> copies/reaction. The developed nested PCR assay provides new technical support for the accurate detection of DIV1 in global crustacean aquaculture.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142348368","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 : 2024-09-27DOI: 10.1016/j.jip.2024.108210
Vibrio parahaemolyticus, a halophilic food-borne pathogen, possesses an arsenal of virulence factors. The pathogenicity of V. parahaemolyticus results from a combination of various virulence factors. HlyA and hlyIII genes are presumed to function in hemolysis, in addition to tdh and trh in V. parahaemolyticus. To confirm the hemolytic function of genes hlyA and hlyIII, ΔhlyA and ΔhlyIII strains of V. parahaemolyticus were separately constructed via homologous recombination. The cytotoxicity and pathogenicity of the ΔhlyA and ΔhlyIII strains were evaluated using a Tetrahymena-Vibrio co-culture model and an immersion challenge in Litopenaeus vannamei. Results indicated that the hemolytic activity of the ΔhlyA and ΔhlyIII strains decreased by approximately 31.4 % and 24.9 % respectively, compared to the WT strain. Both ΔhlyA and ΔhlyIII exhibited reduced cytotoxicity towards Tetrahymena. Then shrimp infection experiments showed LD50 values for ΔhlyA and ΔhlyIII of 3.06 × 108 CFU/mL and 1.23 × 108 CFU/mL, respectively, both higher than the WT strain’s value of 2.57 × 107 CFU/mL. Histopathological observations revealed that hepatopancreas from shrimps challenged with ΔhlyA and ΔhlyIII exhibited mild symptoms, whereas those challenged with the WT strain displayed severe AHPND. These findings indicate that the ΔhlyA and ΔhlyIII strains are significantly less virulent than the WT strain. In conclusion, both hlyA and hlyIII are vital virulence genes involved in hemolytic and cytotoxic of V. parahaemolyticus.
{"title":"Construction and characterization of different hemolysin gene deletion strains in Vibrio parahaemolyticus (ΔhlyA, ΔhlyIII) and evaluation of their virulence","authors":"","doi":"10.1016/j.jip.2024.108210","DOIUrl":"10.1016/j.jip.2024.108210","url":null,"abstract":"<div><div><em>Vibrio parahaemolyticus</em>, a halophilic food-borne pathogen, possesses an arsenal of virulence factors. The pathogenicity of <em>V. parahaemolyticus</em> results from a combination of various virulence factors. <em>HlyA</em> and <em>hlyIII</em> genes are presumed to function in hemolysis, in addition to <em>tdh</em> and <em>trh</em> in <em>V. parahaemolyticus</em>. To confirm the hemolytic function of genes <em>hlyA</em> and <em>hlyIII</em>, Δ<em>hlyA</em> and Δ<em>hlyIII</em> strains of <em>V. parahaemolyticus</em> were separately constructed via homologous recombination. The cytotoxicity and pathogenicity of the Δ<em>hlyA</em> and Δ<em>hlyIII</em> strains were evaluated using a Tetrahymena-<em>Vibrio</em> co-culture model and an immersion challenge in <em>Litopenaeus vannamei</em>. Results indicated that the hemolytic activity of the Δ<em>hlyA</em> and Δ<em>hlyIII</em> strains decreased by approximately 31.4 % and 24.9 % respectively, compared to the WT strain. Both Δ<em>hlyA</em> and Δ<em>hlyIII</em> exhibited reduced cytotoxicity towards Tetrahymena<em>.</em> Then shrimp infection experiments showed LD<sub>50</sub> values for Δ<em>hlyA</em> and Δ<em>hlyIII</em> of 3.06 × 10<sup>8</sup> CFU/mL and 1.23 × 10<sup>8</sup> CFU/mL, respectively, both higher than the WT strain’s value of 2.57 × 10<sup>7</sup> CFU/mL. Histopathological observations revealed that hepatopancreas from shrimps challenged with Δ<em>hlyA</em> and Δ<em>hlyIII</em> exhibited mild symptoms, whereas those challenged with the WT strain displayed severe AHPND. These findings indicate that the Δ<em>hlyA</em> and Δ<em>hlyIII</em> strains are significantly less virulent than the WT strain. In conclusion, both <em>hlyA</em> and <em>hlyIII</em> are vital virulence genes involved in hemolytic and cytotoxic of <em>V. parahaemolyticus</em>.</div></div>","PeriodicalId":16296,"journal":{"name":"Journal of invertebrate pathology","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142348366","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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