Multigene, genus-wide phylogenetic studies have uncovered the limited taxonomic resolution power of commonly used gene markers, particularly of rRNA genes, to discriminate closely related species of the nematode genus Heterorhabditis. In addition, conflicting tree topologies are often obtained using the different gene markers, which limits our understanding of the phylo- and co-phylogenetic relationships and biogeography of the entomopathogenic nematode genus Heterorhabditis. Here we carried out phylogenomic reconstructions using whole nuclear and mitochondrial genomes, and whole ribosomal operon sequences, as well as multiple phylogenetic reconstructions using various single nuclear and mitochondrial genes. Using the inferred phylogenies, we then investigated co-phylogenetic relationships between Heterorhabditis and their Photorhabdus bacterial symbionts and biogeographical patterns. Robust, well-resolved, and highly congruent phylogenetic relationships were reconstructed using both whole nuclear and mitochondrial genomes. Similarly, whole ribosomal operon sequences proved valuable for phylogenomic reconstructions, though they have limited value to discriminate closely related species. In addition, two mitochondrial genes, the cytochrome c oxidase subunit I (cox-1) and the NADH dehydrogenase subunit 4 (nad-4), and two housekeeping genes, the fanconi-associated nuclease 1 (fan-1) and the serine/threonine-protein phosphatase 4 regulatory subunit 1 (ppfr-1), provided the most robust phylogenetic reconstructions compared to other individual genes. According to our findings, whole nuclear and/or mitochondrial genomes are strongly recommended for reconstructing phylogenetic relationships of the genus Heterorhabditis. If whole nuclear and/or mitochondrial genomes are unavailable, a combination of nuclear and mitochondrial genes can be used as an alternative. Under these circumstances, sequences of multiple conspecific isolates in a genus-wide phylogenetic context should be analyzed to avoid artefactual species over-splitting driven by the high intraspecific sequence divergence of mitochondrial genes and to avoid artefactual species lumping driven by the low interspecific sequence divergence of some nuclear genes. On the other hand, we observed that the genera Heterorhabditis and Photorhabdus exhibit diverse biogeographic patterns, ranging from cosmopolitan species to potentially endemic species, and show high phylogenetic congruence, although host switches have also occurred. Our study contributes to a better understanding of the biodiversity and phylo- and co-phylogenetic relationships of an important group of biological control agents and advances our efforts to develop more tools that are compatible with sustainable and eco-friendly agricultural practices.

• Klíčová slova
• Biological control, Molecular systematics, Phylogenetic species concept, Phylogenetics, Phylogenomics, Sustainable agriculture, Taxonomy,
• MeSH
• Bayesova věta MeSH
• fylogeneze * MeSH
• fylogeografie MeSH
• genetická variace * MeSH
• genom mitochondriální genetika   MeSH
• Photorhabdus genetika   klasifikace   MeSH
• Rhabditoidea genetika   klasifikace   mikrobiologie   MeSH
• sekvenční analýza DNA MeSH
• symbióza genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Entomopathogenic nematodes (EPNs) are biological control agents that naturally kill insect pests, providing an eco-friendly alternative to chemical pesticides. Despite extensive research, the mechanisms behind the recovery process, where infective juveniles (IJs) transition to a parasitic state upon contact with the host, remain unclear. This study investigates the stimulatory effect of insect-derived materials on the recovery of Heterorhabditis bacteriophora IJs. Three materials from Galleria mellonella larvae-bioactive homogenates from live and frozen larvae, and heat-inactivated homogenate-were tested, along with non-host stimuli including filtered water and phosphate-buffered saline (PBS). While none of the materials induced complete recovery of IJs, all triggered the release of excreted/secreted products (ESPs), with consistent protein concentrations across treatments. However, mass spectrometry revealed significant differences in ESP protein composition. IJs exposed to PBS released the highest number of proteins, while bioactive homogenates induced the fewest. Proteins linked to host-parasite interactions, such as alpha-2-macroglobulins and trypsin inhibitor-like proteins, were more abundant in ESPs following exposure to insect-derived materials and PBS. Interestingly, nematodes exposed to water released a substantial number of proteins, comparable to stimulation by heat-inactivated homogenates, though their protein profiles were distinct, reflecting stress responses in the former and host-parasite interaction-related proteins in the latter. Our findings demonstrate that both host-derived and non-biological stimuli can trigger IJs recovery and ESPs release, underscoring the complexity of host-nematode interactions. These results provide novel insights into molecular mechanisms underlying H. bacteriophora parasitism and may contribute to optimizing biocontrol strategies through a better understanding of nematode activation and released ESPs.

• MeSH
• biologická kontrola škůdců MeSH
• hmyz MeSH
• interakce hostitele a parazita * MeSH
• larva MeSH
• můry parazitologie   MeSH
• proteiny červů metabolismus   MeSH
• Rhabditida fyziologie   MeSH
• Rhabditoidea fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• proteiny červů MeSH

Iceland is an isolated, sub-Arctic, oceanic island of volcanic origin in the northern North Atlantic. With a limited faunal diversity and being the most northern point in the distributional range for some species, it is an intriguing model region to study parasite biodiversity and biogeography. Since 2006, there has been a history of intense biodiversity discoveries of freshwater trematodes (Trematoda, Digenea), thanks to the use of integrative taxonomic methods. The majority of digeneans (28 out of 41 known) were characterised with molecular genetic methods and morphological analyses, with some of their life-cycle stages and geographical distribution assessed. A surprising diversity has been discovered, comprising species of the families Allocreadiidae, Cyclocoeliidae, Diplostomidae, Echinostomatidae, Gorgoderidae, Plagiorchiidae, Notocotylidae, Schistosomatidae, and Strigeidae. Many of the recorded species complete their life cycles within Iceland, with three snail species (Ampullaceana balthica, Gyraulus parvus, Physa acuta) known as intermediate hosts. No trematodes endemic for Iceland were found; they appear to be generalists with wide geographical ranges dispersed mainly by migratory birds. Interestingly, fish trematodes recorded in Iceland were found in mainland Europe, indicating that they might be dispersed by anadromous fishes, by human activity, or by migratory birds carrying intermediate hosts. The trematode fauna is mainly Palaearctic, with few species recorded in North America. We highlight the ongoing need for precise species identification via integrative taxonomic methods, which is a baseline for any further ecological studies and adequate epidemiological and conservation measures. Also, there is still a need of obtaining well-preserved vouchers of adults for definite species delimitation.

• Klíčová slova
• Digenea, Gastropoda, Lymnaeidae, Planorbidae, cercariae,
• MeSH
• biodiverzita * MeSH
• hlemýždi parazitologie   MeSH
• infekce červy třídy Trematoda * parazitologie   veterinární   epidemiologie   MeSH
• ryby parazitologie   MeSH
• sladká voda * parazitologie   MeSH
• stadia vývoje MeSH
• Trematoda * klasifikace   genetika   izolace a purifikace   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Geografické názvy
• Island MeSH

BACKGROUND: Venom allergen-like proteins (VALs) are abundant in the excretory-secretory products (ESPs) of numerous parasitic helminths and have been extensively studied for over 30 years because of their potential to interact with host systems. Despite substantial research, however, the precise functions of these proteins remain largely unresolved. Schistosomes, parasites of the circulatory system, are no exception, with 29 SmVAL genes identified in the genome of Schistosoma mansoni to date. The eggs of these parasites, as primary pathogenic agents, interact directly with host tissues and release excretory-secretory products that aid their egress from the host. Although SmVALs have been detected in the egg secretome in the past, direct evidence of their secretion and functional interaction with host molecules has never been demonstrated. These findings fuel the ongoing debate as to whether egg-expressed SmVALs interact with the mammalian host or are rather miracidial proteins synthesized within the egg during larval development. RESULTS: Based on complete revision of the SmVAL family and an associated robust transcriptomic meta-analysis of gene expression across the life cycle, we show that many of SmVAL genes, including 6 newly identified genes, are expressed in the infective larvae-producing stages (eggs and sporocysts). Following localization of two "egg-specific" SmVAL9 and SmVAL29 did not prove active secretion of these molecules into surrounding tissues but were aligned with miracidial structures interfacing with the molluscan host, specifically the larval surface and penetration glands. Finally, we show the complete lack of interactions between candidate SmVAL proteins and an array of 755 human cell receptors via a state-of-the-art SAVEXIS screen. CONCLUSIONS: Overall, we conclude that these "egg" SmVALs are not involved in direct host‒parasite interactions in the mammalian host and are rather proteins employed during intermediate host invasion. Our study revisits and updates the SmVAL gene family, highlighting the limitations of in silico protein function predictions while emphasizing the need for up-to-date datasets and tools together with experimental validation in host-parasite interactions. By uncovering the diversity, expression patterns, and interaction dynamics of SmVALs, we open new avenues for understanding host manipulation and reevaluating orthologous proteins in other helminths.

• Klíčová slova
• CAP, Egg, Miracidium, SAVEXIS, SCP, Schistosomiasis, Transcriptome, Venom allergen-like,
• MeSH
• alergeny * genetika   MeSH
• interakce hostitele a parazita * genetika   MeSH
• ovum metabolismus   MeSH
• proteiny červů * genetika   metabolismus   MeSH
• Schistosoma mansoni * genetika   MeSH
• stanovení celkové genové exprese MeSH
• transkriptom MeSH
• živočišné jedy genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• alergeny * MeSH
• proteiny červů * MeSH
• živočišné jedy MeSH

In this study, morphological and molecular features were used to identify a new Steinernema sp. from Kerala, India. Morphological and molecular features provide evidence for placing the new species into the longicaudum clade. The new species is characterized by the following morphological features: infective juveniles with a body length of 1067 μm (914-1268 μm); a distance from the anterior end to excretory pore of 82 μm (73-92 μm); a distance from anterior end to nerve ring of 105 μm (91-118 μm). The distinguishing feature of the infective juveniles of S. keralense n. sp. is the presence of seven ridges in the mid-body region, while all other species classified within the logicaudum clade to date are characterized by eight ridges. The first-generation males are characterised by 25 genital papillae, very short spicules, with a length of 68 μm (60-72 μm), and the SW% ratio is 136 (114-169). The new species is further characterized by sequences of the internal transcribed spacer and partial 28S regions of the ribosomal DNA. Phylogenetic analyses show that S. keralense n. sp. is closely related to species within the longicaudum clade.

• Klíčová slova
• glaseri-group, longicaudum clade, molecular characterization, phylogenetic systematics, taxonomy,
• MeSH
• DNA helmintů * genetika   MeSH
• fylogeneze * MeSH
• mezerníky ribozomální DNA * genetika   MeSH
• Rhabditida * anatomie a histologie   klasifikace   genetika   izolace a purifikace   MeSH
• ribozomální DNA genetika   MeSH
• RNA ribozomální 28S * genetika   MeSH
• sekvenční analýza DNA MeSH
• shluková analýza MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Indie MeSH
• Názvy látek
• DNA helmintů * MeSH
• mezerníky ribozomální DNA * MeSH
• ribozomální DNA MeSH
• RNA ribozomální 28S * MeSH

Toxocara canis is a widespread parasite of canids with a wide range of paratenic hosts, but also one of the overlooked agents causing nervous system infections of humans. Previous experimental infections of mice demonstrated the impact of high infection doses of larvae on neurobehavioral disorders and pathological changes. In contrast to previous studies, we aimed to investigate the long-term (up to 100 weeks) impact of low- to high-dose infection in mice. We focused on their physical condition, motor skills, and the accompanying pathologies in the brain. Three groups of BALB/c mice were infected with 10, 100, and 1000 T. canis larvae/mouse and specific anti-T. canis excretory-secretory antigens immunoglobulin G antibody response, general condition, and motor skills were tested in defined intervals within 100 weeks after infection. The number of larvae in selected organs was assessed and the pathological changes in the brain were studied histologically. As a result, subtle to severe impairments in general condition and motor skills were detected, with generally earlier onsets occurring the higher the infection dose was. The specific immunoglobulin G antibody levels corresponding to the infection dose were detected in all infected groups. Necrosis, cellular infiltrations, and foamy cells developed in moderate- and high-infection dose mice, in contrast with hemorrhages detected in all groups. This study demonstrated the long-term negative impact of T. canis infection on the paratenic host, particularly at moderate and high infectious doses. Although pathological changes in the brain were observed even in low-infection dose mice, their physical and motor condition was comparable to the control group.

• Klíčová slova
• Toxocara canis, brain pathology, helminth infection, mice, motor impairment, nematode infection, parasite, toxocarosis,
• MeSH
• imunoglobulin G * krev   MeSH
• larva MeSH
• modely nemocí na zvířatech MeSH
• mozek * parazitologie   patologie   MeSH
• myši inbrední BALB C * MeSH
• myši MeSH
• protilátky helmintové * krev   MeSH
• Toxocara canis * imunologie   MeSH
• toxokaróza * parazitologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• imunoglobulin G * MeSH
• protilátky helmintové * MeSH

Extracellular vesicles (EVs) from parasites have been identified as potent modulators of host-parasite interactions. However, their biogenesis and secretory activity are still poorly understood. Here we present a comprehensive examination of the secretory dynamics of two distinct EV fractions isolated from the adult tapeworm Hymenolepis diminuta. Additionally, we perform a detailed analysis of changes in proteomic content and morphology during EV secretion, utilising electron tomography to shed light on a previously described novel mechanism of EV biogenesis via bead-like protrusion. Our findings reveal a significant decrease in EV secretion between 24 and 48 h of in vitro cultivation when external host stimuli are no longer present. Finally, this study addresses, for the first known time, the potential bias in EV analysis resulting from extended in vitro cultivation of model parasites.

• Klíčová slova
• ESP, Electron microscopy, Exosomes, LC–MS/MS, Proteins, Secretion, Size exclusion chromatography,
• MeSH
• extracelulární vezikuly * metabolismus   MeSH
• hymenolepiáza parazitologie   metabolismus   MeSH
• Hymenolepis diminuta * metabolismus   MeSH
• interakce hostitele a parazita * MeSH
• proteomika MeSH
• tomografie elektronová MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Intracellular protein aggregation causes proteotoxic stress, underlying highly debilitating neurodegenerative disorders in parallel with decreased proteasome activity. Nevertheless, under such stress conditions, the expression of proteasome subunits is upregulated by Nuclear Factor Erythroid 2-related factor 1 (NRF1), a transcription factor that is encoded by NFE2L1. Activating the NRF1 pathway could accordingly delay the onset of neurodegenerative and other disorders with impaired cell proteostasis. Here, we present a series of small-molecule compounds based on bis(phenylmethylen)cycloalkanones and their heterocyclic analogues, identified via targeted library screening, that can induce NRF1-dependent downstream events, such as proteasome synthesis, heat shock response, and autophagy, in both model cell lines and Caenorhabditis elegans strains. These compounds increase proteasome activity and decrease the size and number of protein aggregates without causing any cellular stress or inhibiting the ubiquitin-proteasome system (UPS). Therefore, our compounds represent a new promising therapeutic approach for various protein conformational diseases, including the most debilitating neurodegenerative diseases.

• Klíčová slova
• DDI2, NGLY1, NRF1(NFE2L1), Proteasome, Protein aggregates, Small molecules,
• MeSH
• aktivace transkripce účinky léků   MeSH
• autofagie účinky léků   MeSH
• Caenorhabditis elegans * účinky léků   metabolismus   MeSH
• faktor 1 související s NF-E2 metabolismus   genetika   MeSH
• knihovny malých molekul farmakologie   MeSH
• lidé MeSH
• patologická konformace proteinů metabolismus   farmakoterapie   MeSH
• proteasomový endopeptidasový komplex * metabolismus   MeSH
• proteinové agregáty * účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• faktor 1 související s NF-E2 MeSH
• knihovny malých molekul MeSH
• proteasomový endopeptidasový komplex * MeSH
• proteinové agregáty * MeSH

The human pathogens Plasmodium and Schistosoma are each responsible for over 200 million infections annually, especially in low- and middle-income countries. There is a pressing need for new drug targets for these diseases, driven by emergence of drug-resistance in Plasmodium and an overall dearth of drug targets against Schistosoma. Here, we explored the opportunity for pathogen-hopping by evaluating a series of quinoxaline-based anti-schistosomal compounds for their activity against P. falciparum. We identified compounds with low nanomolar potency against 3D7 and multidrug-resistant strains. In vitro resistance selections using wildtype and mutator P. falciparum lines revealed a low propensity for resistance. Only one of the series, compound 22, yielded resistance mutations, including point mutations in a non-essential putative hydrolase pfqrp1, as well as copy number amplification of a phospholipid-translocating ATPase, pfatp2, a potential target. Notably, independently generated CRISPR-edited mutants in pfqrp1 also showed resistance to compound 22 and a related analogue. Moreover, previous lines with pfatp2 copy number variations were similarly less susceptible to challenge with the new compounds. Finally, we examined whether the predicted hydrolase activity of PfQRP1 underlies its mechanism of resistance, showing that both mutation of the putative catalytic triad and a more severe loss of function mutation elicited resistance. Collectively, we describe a compound series with potent activity against two important pathogens and their potential target in P. falciparum.

• MeSH
• antimalarika * farmakologie   MeSH
• chinoxaliny * farmakologie   MeSH
• léková rezistence účinky léků   MeSH
• lidé MeSH
• Plasmodium falciparum * účinky léků   MeSH
• protozoální proteiny metabolismus   genetika   MeSH
• Schistosoma účinky léků   MeSH
• schistosomóza farmakoterapie   MeSH
• tropická malárie farmakoterapie   parazitologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antimalarika * MeSH
• chinoxaliny * MeSH
• protozoální proteiny MeSH

Acanthocephalan parasites are often overlooked in many areas of research, and satellitome and cytogenetic analyzes are no exception. The species of the genus Acanthocephalus are known for their very small chromosomes with ambiguous morphology, which makes karyotyping difficult. In this study, we performed the first satellitome analysis of three Acanthocephalus species to identify species- and chromosome-specific satellites that could serve as cytogenetic markers. RepeatExplorer2 revealed a remarkably high number of species-specific repeats, with a predominance of satellite DNAs, alongside variations in repetitive content between sexes. Five satellites in A. anguillae, two in A. lucii and six in A. ranae were successfully mapped to chromosomes using FISH. Each satellite showed a clustered hybridization signal at specific chromosomal locations, which allowed us to create a schematic representation of the distribution of satellites for each species. These newly identified satellites proved to be useful chromosomal markers for the accurate identification of homologous chromosome pairs. No FISH-positive signals were observed on the supernumerary chromosomes of A. anguillae and A. lucii, supporting the hypothesis that these chromosomes have recent origin.

• Klíčová slova
• Acanthocephala, Fluorescence in situ hybridization, Repeat, RepeatExplorer2, Satellite DNA,
• MeSH
• Acanthocephala * genetika   klasifikace   MeSH
• chromozomy genetika   MeSH
• cytogenetické vyšetření metody   MeSH
• druhová specificita * MeSH
• genetické markery MeSH
• hybridizace in situ fluorescenční * MeSH
• karyotyp MeSH
• karyotypizace metody   MeSH
• satelitní DNA * genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• genetické markery MeSH
• satelitní DNA * MeSH