Presence Of Nematodes Research Articles

AoSte12 Is Required for Mycelial Development, Conidiation, Trap Morphogenesis, and Secondary Metabolism by Regulating Hyphal Fusion in Nematode-Trapping Fungus Arthrobotrys oligospora.

Nematode-trapping (NT) fungi are a unique group of carnivorous microorganisms that can capture and digest nematodes by producing ingenious trapping devices (traps). Arthrobotrys oligospora, a representative NT fungus, can develop adhesive three-dimensional networks for nematode predation. Hyphal fusion is indispensable for the trap formation of A. oligospora. Here, we characterized an orthologous Ste12 protein (AoSte12) in A. oligospora via gene disruption, DNA affinity purification sequencing (DAP-Seq), and multi-omics approaches. The disruption of the Aoste12 gene caused an increase in hyphal fusion and resulted in defects in mycelial growth, conidiation, trap morphology, and stress resistance, as well as reducing the number of nuclei and lipid droplet accumulation. Moreover, transcriptome and DAP-Seq analysis revealed that AoSte12 was involved in cellular processes associated with growth, cell fusion, the tricarboxylic acid cycle, vesicles, actin filaments, and lipid metabolism. In addition, combining metabolome with transcriptome and DAP-Seq analysis indicated that AoSte12 was involved in the mitogen-activated protein kinase signaling pathway, lipid metabolism, and secondary metabolites. A yeast two-hybrid assay revealed that AoSte12 can interact with diverse proteins, such as the MAK-2 orthologue protein Fus3, the vacuolar sorting protein Pep3, and UDP-glycosyltransferase. Our results suggest that AoSte12 plays an indispensable role in hyphal fusion and thus regulates sporulation and trap morphogenesis. These results provide deep insights into the connection between hyphal fusion and trap formation in NT fungi. IMPORTANCE Nematode-trapping (NT) fungi are an important natural enemy of nematodes and can capture their prey by producing traps. Hyphal anastomosis and fusion are important for mycelial growth and the colony morphological development of filamentous fungi and are also crucial for the trap morphogenesis of NT fungi. Arthrobotrys oligospora can form complex three-dimensional networks (traps) when sensing the presence of nematodes. This study revealed that AoSte12 is indispensable for hyphal fusion and that it regulates mycelial growth, conidiation, trap morphogenesis, stress resistance, the number of nuclei, and lipid droplet accumulation in A. oligospora. In addition, DNA affinity purification sequencing, transcriptome, and metabolome analyses further revealed that AoSte12 is involved in the mitogen-activated protein kinase pathway, lipid metabolism, and secondary metabolism. Overall, these findings expand the important role of AoSte12 in NT fungus A. oligospora and provide a broad foundation for elucidating the regulatory mechanism of trap development and the lifestyle transitions of pathogenic fungi.

The Infestation of Fleas of the Long-Tailed Souslik with Entomoparasitic Nematodes in Tuva Mountain Natural Plague Focus

Entomoparasitic nematodes are supposed to be a link between parts of Yersinia pestis population in the environment and the flea vector. The aim of the study was to assess the prevalence and intensity of infestation in the fleas of the long-tailed souslik with entomoparasitic nematodes on the territory of Mongun-Taiginsky station in the Tuva natural plague focus. Materials and methods. Fleas were collected during the scheduled epizootiological surveys in 2019–2021. In the course of taxonomic identification the presence of parasitic nematodes was registered. In order to evaluate the intensity of nematode invasion, a total of 190 fleas were dissected. The number of adult parasitizing females and presence of larvae was recorded. Statistical processing of the data was performed with the help of conventional methods using the Excel software. The criterion χ2 was applied; the influence of various factors (species, gender of fleas) on the studied parameters was assessed through single- and two-factor analysis of variance. Results and discussion. During three years of observations, entomoparasitic nematodes were found in six species of fleas: Citellophilus tesquorum, Frontopsylla elatoides, Rhadinopsylla li transbaikalica, Frontopsylla hetera, Oropsylla alaskensis, and Neopsylla mana. The differences in infestation with nematodes between the species are presented. The highest invasion rate – 25.1–25.6 % – is observed in Rh. li transbaikalica. The gender of leas does not influence their infestation. It is established that invaded fleas are more often found in the nest than in the fur of animals, they are less actively migrate to the burrow entrance compared to not invaded ones. Evaluation of infestation prevalence has revealed that fleas Rh. li transbaikalica are the hosts for nematodes of mono- or oligoxenic species, which do not occur in other fleas.

Genetic diversity of Contracaecum rudolphii sp. A (Nematoda: Anisakidae) parasitizing the European Shag Phalacrocorax aristotelis desmarestii from the Spanish Mediterranean coast.

Sibling species of the Contracaecum rudolphii (s.l.) complex are habitual endoparasites of cormorants of the Phalacrocoracidae family, worldwide. In Europe, the two species, C. rudolphii sp. A and C. rudolphii sp. B, have been identified. However, information regarding the occurrence and distribution of these anisakids in cormorants from Spain is scarce. In the present study, 20 specimens of the European Shag, Ph. aristotelis desmarestii, from the western Mediterranean Spanish marine coast were parasitologically analyzed for the presence of nematodes. All hosts were found parasitized with Contracaecum specimens (n = 1,517). A representative subsample was genetically identified as C. rudolphii sp. A by sequence analysis of the mtDNA cox2 gene and the ITS1 and ITS2 regions of the rDNA. This represents the first report of C. rudolphii sp. A from the Spanish Mediterranean waters. Population genetic analysis was performed including other C. rudolphii sp. A specimens from the west Sardinian and the Tyrrhenian Sea. At the intraspecific level, a significant genetic differentiation (Fst ≈ 0.08, p < 0.00001) between the metapopulation from the Spanish Mediterranean coast and that from the Sardinian waters was observed; whereas, no differentiation was found between metapopulations of the parasite from the Spanish and the Tyrrhenian Italian coast. The findings highly support the hypothesis of the adaptation of the life cycle of C. rudolphii sp. A in brackish and marine ecosystems. Furthermore, the results on the population genetics of C. rudolphii sp. A suggest the possible role of the migration routes of wintering populations of cormorants in the Mediterranean Sea in influencing the parasite genetic structure.

Six Genera of Plant-Parasitic Nematodes From Bangladesh

The presence of plant-parasitic nematodes causing crop loss every year had been overlooked in the existing fruits, vegetables and flowers cultivation system in Bangladesh. Therefore, the study was conducted to isolate and identify plantparasitic nematodes from soil and infected plant-parts of fruits (banana, orange), vegetables (pointed gourd, tomato and brinjal) and flower (gerbera) from the districts of Jashore, Jhenaidah, Gazipur and Sylhet during 2017-18 and 2018-19 cropping seasons. A total of 68 samples of which 20 fruit samples, 45 vegetables samples and 3 flower samples were collected and observed for nematode infestation. Baermann funnel method was used to extract the active nematodes from plant parts and Cobb’s method was used for the isolation of nematodes from soil samples. Different morphological structures of the nematodes viz. esophagus, median bulb, basal bulb, intestine, reproductive structures (vulba, bursa), etc. were used to identify the nematodes. To identify Meloidogyne spp. from root knot of tomato, brinjal and gerbera, juvenile larvae J2 and perineal pattern of female nematodes were used. A total of six genera of nematodes were identified and all of them were under the order Tylenchida. The nematode genera were Tylenchorhynchus sp., Tylenchus sp., Hoplolaimus sp., Helicotylenchus sp., Pratylenchus sp. and Meloidogyne spp. The root-knot nematode, Meloidogyne incognita was recorded for the first time in flower crop gerbera in Bangladesh.&#x0D; Bangladesh J. Agril. Res. 46(3): 275-284, September 2021

The presence of zoonotic protozoans and nematodes on contaminated street food dipping Sauce in Tangub City, Mindanao, Philippines | IJMM 2023

The presence of zoonotic protozoans and nematodes on contaminated street food dipping Sauce in Tangub City, Mindanao, Philippines | IJMM 2023

CARACTERIZACIÓN DE LA MICROBIOTA FECAL EN CABALLOS CON CIATOSTOMOSIS EN MÉXICO

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; The excess of antimicrobials and anthelmintics cause important dysbiosis processes in equines, as well as resistance phenomena mainly in the communities of bacteria, archaea, protozoa, and helminths. The study of the equine microbiome is becoming more and more relevant to understand the biotic processes of the gastrointestinal tract. In colon and cecum, the role of cyathostomins as part of the microbiome is still unexplored. While interaction with certain bacterial groups may be key to the understanding of parasitism. &lt;strong&gt;Objective:&lt;/strong&gt; To characterize the microbiota in feces of yearling naturally infected with cyathostomins in a quarter-horse farm in Sierra de Lobos, Guanajuato, Mexico. &lt;strong&gt;Methodology:&lt;/strong&gt; Weights were measured and obtained the parasite burden in feces, from which samples were transfer and processing in the laboratory for DNA extraction and later sent for sequencing and analysis. &lt;strong&gt;Results:&lt;/strong&gt; Average weight of the colts was 399 kg, and the average weight of the fillies was 432 kg. All horses were high shedders: 1,390 ± 698 egg per gram of feces. Alpha and beta diversity analyses indicated no differences within the microbial community between colts and fillies. Main bacteria at Phyla in both groups (females; males) were Bacteroidetes (37%; 37%), Firmicutes (46%; 37%), Verrucomicrobia (4%; 10%), Spirochaetes 5%; 4%) and Proteobacteria (1%; 3%). At Class level the principal identified groups were Bacteroidia (31%; 31%), Clostridia (43%; 35%), at Order level are Bacteroidales (31%; 31%) and Clostridiales (43%; 35%). Main bacteria at Family level were Ruminococcaceae (19%; 11%), Lachnospiraceae (15%; 6%) and non-assigned family Bacteriodales (19%; 21%). The most abundant non-assigned bacterial Genra were Bacteroidales (26%; 27%), Ruminococcaceae (10%; 5%) y Lachnospiraceae (9%; 6%); the assigned bacterial Genra were &lt;em&gt;Clostridium&lt;/em&gt; (5%; 9%) and &lt;em&gt;Treponema&lt;/em&gt; (4% y 3%). The most abundant non-assigned bacterial Species were&lt;em&gt; Methanocorpusculaceae&lt;/em&gt; sp (19%; 22%), &lt;em&gt;Pedobacter&lt;/em&gt; sp (10%; 5%), &lt;em&gt;Bacteroidales&lt;/em&gt; sp (9% y 6%) and &lt;em&gt;Prevotella&lt;/em&gt; sp (4% y 3%); the assigned bacterial species were &lt;em&gt;Fibrobacter succinogenes&lt;/em&gt; (2%; 1%), &lt;em&gt;Succinispira mobilis&lt;/em&gt; (1%; 1%). &lt;strong&gt;Implications:&lt;/strong&gt; It is suggested that environmental factors and feeding are aspects that regulate the parasitic burden and the bacterial composition in this studied population. This is a short communication of the finding of the components of the microbiota and is relevant in Mexico for future studies, however it is imperative to explore the composition of the metacommunity of a horse free of cyathostomines. &lt;strong&gt;Conclusion:&lt;/strong&gt; Considering that these nematodes are in the cecum and colon, where this microbiota was inferred, and that it is not known whether this interaction is beneficial or detrimental, the study of the microbiome is imperative. In the study, no horse presented clinical signs or colic due to the presence of nematodes.&lt;/p&gt;

Prospects for fungal bioremediation of unburied waste packages from the Goiânia radiological accident.

Goiânia, the Goiás State capital, starred in 1987, where one of the largest radiological accidents in the world happened. A teletherapy machine was subtracted from a derelict radiotherapy clinic and disassembled by scavengers who distributed fragments of the 50 TBq 137CsCl source among relatives and acquaintances, enchanted by the blue shine of the substance. During the 15days before the accident was acknowledged, contaminated recycling materials were delivered to recycling factories in four cities in the state of São Paulo, Brazil, in the form of recycling paper bales. The contaminated bales were spotted, collected, and stored in fifty 1.6 m3 steel boxes at the interim storage facility of the Nuclear and Energy Research Institute (IPEN). In 2017, a check of the content was performed in a few boxes and the presence of high moisture content was observed even though the bales were dry when conditioned and the packages were kept sealed since then. The main objective of this work was to report the fungi found in the radioactive waste after they evolved for 30years in isolation inside the waste boxes and their role in the decay of the waste. Examination of the microbiome showed the presence of nematodes and fungal communities. The fungi species isolated were Aspergillus quadricinctus, Fusarium oxysporum, Lecanicillium coprophilumi, Scedosporium boydii, Scytalidium lignicola, Xenoacremonium recifei, and Pleurostoma richardsiae. These microorganisms showed a significant capacity to digest cellulose in our trials, which could be one of the ways they survive in such a harsh environment, reducing the volume of radioactive paper waste. These metabolic abilities give us a future perspective of using these fungi in biotechnology to remediate radioactively contaminated materials, particularly cellulose-based waste.

Manejo de nematoides-de-galha em quiabeiro por meio de enxertia em vinagreira-roxa e vinagreira-flor-de-veludo

Abstract The objective of this work was to evaluate the performance of okra grafted onto Hibiscus spp. in the presence and absence of three root knot nematode species. The experimental design was completely randomized in a 4x4 factorial arrangement with ten replicates. The first factor consisted of the following four rootstocks: kenaf (Hibiscus cannabinus), false roselle (Hibiscus acetosella), self-grafted, and non-grafted. The second factor was the inoculation of 5,000 eggs and second-stage juveniles of Meloidogyne incognita, Meloidogyne javanica, and Meloidogyne enterolobii in okra plants, plus an uninoculated control. Vegetative development, agronomic performance, and nematode reproduction were evaluated. The grafting of okra onto Hibiscus spp. in the presence of root-knot nematodes provided a greater plant height, scion length, fresh shoot mass, number of fruits, and yield, when compared with self-grafted and non-grafted plants. The averages of the root-knot nematode reproduction factor were low in the plants grafted onto Hibiscus spp., indicating that grafting in the presence of root-knot nematodes is capable of maintaining okra vegetative development and yield.

Gurltia paralysans infection in a domestic cat in the São Paulo state, southeastern Brazil

Gurltia paralysans is a nematode first described in 1933 in Chile, causing a syndrome called feline crural parasitic paraplegia. Insects, mollusks, frogs, lizards, and rodents are paratenic hosts of this nematode, and cats probably become infected by ingesting them. This report aims to discuss the main anatomopathological findings of gurltiosis in a cat submitted to necropsy in a laboratory in Ribeirão Preto city, São Paulo state, southeastern Brazil, being the first case reported in this state. The main necroscopic findings were extramedullary reddened areas below the leptomeninges in the cervical and lumbar segments of the spinal cord. The histopathological examination showed marked thickening of the leptomeninges in the lumbar segment of the spinal cord, with marked neovascularization and fibrosis associated with eosinophilic and mononuclear inflammatory infiltration, as well as the presence of intravascular nematodes. The diagnosis of this lesion was chronic segmental meningomyelitis associated with intralesional parasites. Although uncommon, feline gurltiosis is a neglected parasitic disease that should be included as a differential diagnosis of paraparesis in domestic cats.

Diversity and abundance of terrestrial molluscs and their associated nematode fauna in urban kitchen gardens in the city of Rio de Janeiro, Brazil

Terrestrial molluscs can become agricultural pests and transmit parasites, playing an important role in different biological communities. In the present study, we evaluated the diversity and abundance of this group in two horticultural areas in Rio de Janeiro (Manguinhos and Jacarepaguá neighborhoods), as well the presence of parasitic nematodes associated with these molluscs. We collected specimens in the austral spring and summer, with four sites being sampled within each study area, including malabar spinach, sweet potato, chicory greens, and cassava plantations, and one site in an adjacent, non-cultivated area. We collected a total of 522 live mollusc specimens and identified 16 species from 10 different families. The greatest abundance of molluscs was recorded in summer (363) and at Jacarepaguá (309). Overall, 174 (57%) of the 303 specimens analyzed parasitologically were positive for nematodes. Larvae of superfamily Metastrongyloidea, which includes nematodes that are a concern for public health and veterinary medicine, were found parasitizing the slug Sarasinula linguaeformis, in Manguinhos. Our results contribute to understanding of the diversity of terrestrial molluscs occurring in kitchen gardens in the city of Rio de Janeiro, and provide important insights for generating subsidies for health education actions and control of parasitic diseases transmitted by them.

Evaluation of Soybean Genotypes (&amp;lt;i&amp;gt;Glycine max&amp;lt;/i&amp;gt; L. Merr.) Susceptibility to Parasitic Nematodes in Western Part of Burkina Faso

Parasitic nematodes have been reported as one of the major constraints to soybean production worldwide. The majority of nematodes are so-called “free-living” and feed mainly on bacteria, fungi, protozoa and other nematodes. In Burkina Faso, the presence of parasitic nematodes has been reported in crops such as rice and sorghum. The objective of this study was to identify the genera and species of nematodes associated with soybean production in Burkina Faso. Investigations were carried out on 24 genotypes of a medium-maturity group of soybean at the Farako-Ba research station. Soil samples were taken from the trial soil before its installation. At harvest, soil samples with roots were taken from each genotype in the elementary plots. The composite sample is represented by 4 lots of soil samples with roots. Extractions and counts of nematodes were performed on the different lots. In total, 7 genera of plant-parasitic nematodes associated with soybean were identified. Among these genera, Pratylenchus (100% of infected genotypes), Helicotylenchus (97.28%) and Scutellonema (94.44%) were the most prevalent in terms of frequency and abundance. Some soybean genotypes were less susceptible to the genus Pratylenchus is known to be highly pathogenic in soybean. These were mainly the genotypes TGX2025-10E, TGX2023-3E and TGX2025-14E.

Soil Census of Kentucky High Tunnels Reveals Statewide Distribution of Two Meloidogyne Species

High tunnels are passively heated and cooled structures used for specialty crop production that can increase marketable yields, extend the growing season, and protect crops from harsh weather. Kentucky has more than 1,500 high tunnels, and although there are many benefits, production still has several challenges. High soil temperatures, lack of rotation and sanitation, and intensive and continuous cropping make high tunnels hospitable environments for the root-knot nematode (RKN; Meloidogyne spp.). This plant parasite infects roots, causing chlorosis, wilting, stunting, and yield loss. Determining the presence, population density, and species of RKN is important to inform management strategies. To our knowledge, this is the first research aimed at determining the presence and distribution of RKN across Kentucky. From 2019 to 2022, we sampled the soil in 175 high tunnels in 62 counties. The characteristics of production system, soil type, crop rotation, and high tunnel age were collected to analyze with RKN presence, species, and soil population density. Of the soil samples collected, 45% had no presence of RKN. Among those samples where RKNs were observed, 55% were identified as M. incognita, 39% as M. hapla, and 4% as M. arenaria. RKN presence was dependent on production system and crop rotation, whereas RKN species was dependent on production system and soil type. With over half of the sampled high tunnels infested with RKN, this project justifies further research for management strategies for RKN, especially those that are sustainable species-specific options and appropriate for commercial high tunnels.

The effect of auxin status driven by bacterivorous nematodes on root growth of Arabidopsis thaliana

Bacterivorous nematodes are one of the dominant microbial organisms and play an important role in shaping the bacterial community and hormone dynamics in rhizosphere soils. It has been found that the presence of bacterivorous nematodes potentially regulate indole-3-acetic acid (IAA) content in soils by interacting with the status of IAA-producing bacteria, and eventually act on the growth of plant roots. However, the mechanism behind this interaction in broad soil ecosystems remains unknown. This study reveals the interaction between bacterivorous nematodes and the soil bacterial community, especially IAA-producing bacteria, based on denaturing gradient gel electrophoresis (DGGE) analysis. The results of DGGE showed that the bacterial diversity in soil was increased by inoculation of nematodes during certain periods of plant culture, and was also affected by the genotype of the Arabidopsis thaliana (Johannes Thal, 1577) plants. The variation in soil bacterial communities among the treatments with different genotypes of A. thaliana and nematodes indicated that the soil bacterial community structure was affected by both genotype and nematode grazing. Furthermore, we measured the root architectures of four genotypes of A. thaliana, including wild type (Col-0), two IAA-insensitive mutants (Axr5 and Axr3–1), and DR5::GUS transgenic type (IAA sensitive) under different conditions of bacterivorous nematode inoculation. We found that the root architecture of the IAA-sensitive A. thaliana developed more tips and slender roots under inoculation with activated bacterivorous nematodes, while the root architectures of auxin-insensitive A. thaliana mutants showed no significant differences between alive and inactivated bacterivorous nematodes, even though the IAA content increased in the soil under inoculation with alive nematodes. This study confirms that the presence of bacterivorous nematodes in soils increases the soil IAA content significantly by regulating the bacterial community structure, which leads to an accumulation of auxin in the root tips of A. thaliana, and eventually enhances the plant root growth.

Analysis of supplemental wildlife feeding in Mississippi and environmental gastrointestinal parasite load.

Wildlife species are host to a variety of gastrointestinal parasites (GIPs). Artificially concentrating animals may increase the risk of disease spread due to increased GIP load and associated environmental load. Supplemental feeding of deer is common among hunters and known to concentrate animals, but there is limited knowledge of how it affects GIP environmental load. GIP load was compared between ecologically-equivalent pairs of sites in Mississippi with and without year-round supplemental feeding (average distance between pairs = 147 m). During May-August in 2019 and 2020, feces from white-tailed deer and raccoons were collected and examined for the presence of nematodes, coccidia, Giardia spp., Cryptosporidium spp., and Baylisascaris procyonis. On average, fed sites had 8 more deer (241% increase) and 2 more raccoon fecal piles (540% increase) than unfed sites. Average parasite loads for individual fecal samples did not differ between fed and unfed sites, but the greater number of deer and raccoon fecal piles at fed sites (p < 0.0001) produced 231% and 308% greater environmental loads of nematodes and coccidia, respectively. Spin feeders, the only feeder type that distributed feed on the ground, had 326% more coccidia in feces on average compared to other feeder types (p < 0.03). These results show that supplemental feeding of white-tailed deer, especially with spin feeders, increases environmental loads of GIP and the potential for transmission of parasitic diseases.

Antarctic biodiversity predictions through substrate qualities and environmental DNA

Antarctic conservation science is crucial for enhancing Antarctic policy and understanding alterations to terrestrial Antarctic biodiversity. Antarctic conservation will have limited long‐term impacts in the absence of large‐scale biodiversity data, but if such data were available, it is likely to improve environmental protection regimes. To enable the prediction of Antarctic biodiversity across continental spatial scales through proxy variables, in the absence of baseline surveys, we linked Antarctic substrate‐derived environmental DNA (eDNA) sequence data from the remote Antarctic Prince Charles Mountains to a selected range of concomitantly collected measurements of substrate properties. We achieved this through application of a statistical method commonly used in machine learning. Our analysis indicated that neutral substrate pH, low conductivity, and certain substrate minerals are important predictors of the presence of basidiomycetes, chlorophytes, ciliophorans, nematodes, and tardigrades. A bootstrapped regression revealed how variations in the identified substrate parameters influence probabilities of detecting eukaryote phyla across vast and remote areas of Antarctica. We believe that our work will improve future taxon distribution modeling and aid in developing more targeted surveys of biodiversity conducted under logistically challenging conditions.

Moxidectin use in Scottish sheep flocks suggests a need for clearer product labelling and communication of updated SCOPS guidelines.

Guidelines for sustainable use of moxidectin were established in 2020. This study aimed to identify how Scottish sheep farmers are using this key endectocide and estimate its effectiveness against gastrointestinal nematodes. Questionnaires were distributed to sheep farmers across Scotland, and analysis focused on moxidectin use in relation to Sustainable Control of Parasites in Sheep (SCOPS) guidelines. Farmers using moxidectin in their flock volunteered to submit post-treatment sheep faecal samples, which were analysed for the presence of gastrointestinal nematodes using faecal egg counts with polymerase chain reaction to determine species. Despite 70% of farmers using moxidectin in 2020, knowledge levels varied: 24% of farmers included other anthelmintics when asked about moxidectin use. Moxidectin was used for a wide variety of reasons, and most farmers did not consistently follow SCOPS guidelines. Despite only 2 of 76 farmers reporting failure of moxidectin treatment, gastrointestinal nematodes were found following moxidectin treatment on five out of six farms tested and included Teladorsagia circumcincta, Cooperia curticei, Haemonchus contortus and Nematodirus sp. Findings from this project indicate the need for improved anthelmintic product labelling and farmer support to encourage sustainable use. The presence of nematodes in treated animals is suggestive of anthelmintic resistance.

The cAMP-PKA pathway regulates prey sensing and trap morphogenesis in the nematode-trapping fungus Arthrobotrys oligospora.

Sensing environmental factors and responding swiftly to them is essential for all living organisms. For instance, predators must act rapidly once prey is sensed. Nematode-trapping fungi (NTF) are predators that use “traps” differentiated from vegetative hyphae to capture, kill, and consume nematodes. These traps undergo drastic and rapid morphological changes upon nematode induction. Multiple signaling hubs have been shown to regulate this remarkable process. Here, we demonstrate that the conserved cAMP-PKA signaling pathway exerts a crucial role in trap morphogenesis of the nematode-trapping fungi Arthrobotrys oligospora. A gene deletion mutant of the PKA catalytic subunit TPK2 proved insensitive toward nematode presence. Moreover, we show that the G protein alpha subunit GPA2 acts upstream of adenylate cyclase, with GPA2 deletion resulting in substantially reduced trap formation, whereas exogenous provision of cAMP rescued the prey-sensing and trap morphogenesis defects of a gpa2 mutant. Thus, we show that cAMP production triggered by G protein signaling and downstream PKA activity are vital for prey-sensing and trap development in A. oligospora, demonstrating that this highly conserved signaling pathway is critical for nematode-trapping fungi and nematode predator–prey interactions.

Nematode Parasites of the European Pilchard, Sardina pilchardus (Walbaum, 1792): A Genuine Human Hazard?

Simple SummaryThe European pilchard is one of the most frequently consumed fish species in Mediterranean countries, especially in Italy and Spain, and has been reported as the cause of at least eight human anisakidosis cases in Spain since 1991, the parasitic disease caused by the ingestion of fish or cephalopods infested by the larval stage of anisakid nematodes. With the aim to shed light on the potential human parasitosis risk posed by these nematode larvae, we helminthologically analyzed a total of 350 sardines (European pilchard) captured in the Atlantic Ocean (175 sardines) and the Mediterranean Sea (175 specimens), acquired in various Spanish nationwide supermarket chains. The statistical analysis of some helminth parameters revealed a higher presence of nematodes belonging to the genus Hysterothylacium (frequency of parasitation of 24.29%; total mean parasite burden of 2.36), usually considered non-parasitic for humans (only three cases reported worldwide), when compared to nematodes of the genus Anisakis (5.71%; 0.16). The human anisakidosis risk after the consumption of raw or undercooked sardines and the role of Hysterothylacium, the most frequent nematode, is discussed, providing information to consumers. To avoid human infection by anisakid larval nematodes, the established preventive measures are confirmed and new ones are proposed.The European pilchard is one of the most frequently consumed fish species in Mediterranean countries, especially in Italy and Spain, and has been reported as the cause of at least eight human anisakidosis cases in Spain. With the aim to shed light on the potential human parasitosis risk posed by nematode larvae belonging to families Anisakidae or Raphidascarididae, a total of 350 sardines captured in the Atlantic Ocean (175 specimens) and the Mediterranean Sea (175 specimens), acquired in various Spanish nationwide supermarket chains, were helminthologically analyzed. The statistical analysis of some helminth parameters revealed a higher presence of nematodes belonging to the genus Hysterothylacium (prevalence 24.29%; mean abundance of 2.36), usually considered non-parasitic for humans (only three cases reported worldwide), when compared to nematodes of the genus Anisakis (5.71%; 0.16). The human anisakidosis risk after the consumption of raw or undercooked sardines and the role of Hysterothylacium, the most frequent nematode, is discussed, providing information to consumers. To avoid human infection by anisakid larval nematodes, the established preventive measures are confirmed and new ones are proposed, such as the consumption of sardines preferably caught in the Mediterranean and of small-sized specimens available, and the immediate evisceration after fishing.

Response of the legume Macrotyloma axillare ‘Java’ to different inoculum levels of Meloidogyne javanica and defence responses

This study aimed to examine the relationship between Macrotyloma axillare ‘Java’ and Meloidogyne javanica at different levels of nematode inoculum, and to assess the activity of plant defence enzymes in the presence of nematodes. In Experiment 1, ‘Java’ and soybean (control) were inoculated with 300 to 8000 eggs + second-stage juveniles (J2) of M. javanica in two different periods (Trials 1 and 2). To confirm the results, a third trial was conducted using 1000 to 4000 eggs + J2 per plant. In Experiment 2, β-1,3-glucanase (GLU), phenylalanine ammonia-lyase (PAL), peroxidase (POX), and polyphenol oxidase (PPO) activities were measured in non-inoculated plants and in plants inoculated with 2000 eggs + J2. ‘Java’ presented a reproduction factor (RF) < 1 at all inoculum levels in Trial 1 (RF of 0.17–0.78) and at 2000, 3000, and 6000 eggs + J2 in Trial 2 (RF of 0.47, 0.86, and 0.59, respectively). In Trial 3, ‘Java’ showed a RF < 1 at all inoculum levels except for 3000 eggs + J2 (RF = 1.1). There was no difference in ‘Java’ vegetative variables in relation to inoculum levels in any experiment. In Experiment 2, inoculated plants showed increased GLU, PAL, POX, and PPO activities, when compared with non-inoculated plants. ‘Java’ appears to be moderately resistant to M. javanica, reducing nematode reproduction at different inoculum levels. The plant exhibits increased GLU, PAL, POX, and PPO activities in the presence of M. javanica.

Black Root Rot of Strawberry: A Disease Complex

Historically, root diseases have been a production-limiting problem for the strawberry industry worldwide. Even though this disease is of great economic importance, the etiology remains unresolved. However, soilborne fungal root pathogens, particularly Pythium and Rhizoctonia spp. have been implicated as major role players. Presence of nematodes in soil and favourable environmental conditions also play significant role in the disease development. Development of integrated disease management strategies is dependent upon a more complete understanding of the etiology, biology and ecology of the disease complex.