bluuebunny/crossref_metadata_2025 huggingface dataset:
Zig, Zag, and ’Zyme: leveraging structural biology to engineer disease resistance
Authors: McClelland Alexander J. , Ma Wenbo
Published: April 2024

Dynamic host–pathogen interactions determine whether disease will occur. Pathogen effector proteins are central players in such disease development. On one hand, they improve susceptibility by manipulating host targets; on the other hand, they can trigger immunity after recognition by host immune receptors. A major research direction in the study of molecular plant pathology is to understand effector-host interactions, which has informed the development and breeding of crops with enhanced disease resistance. Recent breakthroughs on experiment- and artificial intelligence-based structure analyses significantly accelerate the development of this research area. Importantly, the detailed molecular insight of effector–host interactions enables precise engineering to mitigate disease. Here, we highlight a recent study by Xiao et al., who describe the structure of an effector-receptor complex that consists of a fungal effector, with polygalacturonase (PG) activity, and a plant-derived polygalacturonase-inhibiting protein (PGIP). PGs weaken the plant cell wall and produce immune-suppressive oligogalacturonides (OGs) as a virulence mechanism; however, PGIPs directly bind to PGs and alter their enzymatic activity. When in a complex with PGIPs, PGs produce OG polymers with longer chains that can trigger immunity. Xiao et al. demonstrate that a PGIP creates a new active site tunnel, together with a PG, which favors the production of long-chain OGs. In this way, the PGIP essentially acts as both a PG receptor and enzymatic manipulator, converting virulence to defense activation. Taking a step forward, the authors used the PG-PGIP complex structure as a guide to generate PGIP variants with enhanced long-chain OG production, likely enabling further improved disease resistance. This study discovered a novel mechanism by which a plant receptor plays a dual role to activate immunity. It also demonstrates how fundamental knowledge, obtained through structural analyses, can be employed to guide the design of proteins with desired functions in agriculture.
Linguistic negotiation in non-profit organization regarding identity. A study on narratives, metaphors and the use of ‘we’
Authors: Vogel Anna
Published: April 2024

The political role of Sweden’s third sector is currently being renegotiated. Are services performed by the voluntary sector a necessary alternative to an inefficient welfare system, or do these services constitute a threat to the universal welfare state? This negotiation is the focus of the paper. My aim is to use linguistic theory, methods, and analysis of empirical data to capture how this negotiation took place within a voluntary non-profit organization. Based on a case study on Save the Children Sweden (where I was an embedded researcher for two years), I suggest that advocates in favour of third sector services gain advantages from certain linguistic features, such as by using ‘we’ in an inclusive, action-oriented way, by using metaphors grounded in activity, and by highlighting a specific version of the organization’s historical narrative.
Addressing Plastic Concern: Behavioral Insights into Recycled Plastic Products and Packaging in a Circular Economy
Authors: Corsini Filippo , Gusmerotti Natalia Marzia , Bartoletti Edoardo , Testa Francesco , Appolloni Andrea , Iraldo Fabio
Published: April 2024

The excessive production and use of new plastic materials pose a critical environmental challenge, and reducing its consumption has emerged as a major global hurdle. Understanding human behavior is thus essential for creating a circular economy for plastics. The study aims to gain insights into consumers' buying habits concerning recycled plastic, which has received relatively little attention in prior research on the subject of environmentally friendly consumer behavior. This study draws on the Theory of Planned Behavior to analyze the factors influencing consumer behavior regarding products and packaging made from recycled plastic. To this end, we employed a questionnaire, which was administered to 511 consumers in Italy. Results support that concerns about plastics and perceived efficacy exert a direct influence on attitudes. Additionally, our findings demonstrate that social norms, attitudes, and perceived behavioral control significantly shape purchasing behaviors concerning recycled plastic. The research contributes to extending the Theory of Planned Behavior model in predicting environmental-friendly behavior by adding new empirical evidence and provides valuable suggestions for companies to develop effective communication strategies and policies to redirect plastic consumption behavior towards less-impacting use of plastic.
Early dementia detection with speech analysis and machine learning techniques
Authors: Jahan Zerin , Khan Surbhi Bhatia , Saraee Mo
Published: April 2024

This in-depth study journey explores the context of natural language processing and text analysis in dementia detection, revealing their importance in a variety of fields. Beginning with an examination of the widespread and influence of text data. The dataset utilised in this study is from TalkBank's DementiaBank, which is basically a vast database of multimedia interactions built with the goal of examining communication patterns in the context of dementia. The various communication styles dementia patients exhibit when communicating with others are seen from a unique perspective by this specific dataset. Thorough data preprocessing procedures, including cleansing, tokenization, and structuring, are undertaken, with a focus on improving prediction capabilities through the combination of textual and non-textual information in the field of feature engineering. In the subsequent phase, the precision, recall, and F1-score metrics of Support Vector Machines (SVM), K-Nearest Neighbours (KNN), Random Forest, and Artificial Neural Networks (ANN) are assessed. Empirical facts are synthesized using text analysis methods and models to formulate a coherent conclusion. The significance of text data analysis, the revolutionary potential of natural language processing, and the direction for future research are highlighted in this synthesis. Throughout this paper, readers are encouraged to leverage text data to embark on their own adventures in the evolving, data-centric world of dementia detection.
Beyond phase-in: assessing impacts on disinformation of the EU Digital Services Act
Authors: Nannini Luca , Bonel Eleonora , Bassi Davide , Maggini Michele Joshua
Published: April 2024

This work proposes a comprehensive research agenda to empirically evaluate the real-world impacts of the European Union’s Digital Services Act (DSA) on combating online disinformation. It provides background on the DSA’s context, mechanisms, timeline, and expected effects on platforms to situate the need for rigorous impact assessment. A detailed legal, technical, psychological, behavioral and ethical critique reveals meaningful gaps in the DSA requiring ongoing regulatory refinement and oversight. Most critically, the paper puts forth an encompassing framework spanning computational analytics, interviews, ethnography, surveys, discourse analysis and mixed methods to rigorously assess the DSA’s multi-dimensional effects on complex factors enabling disinformation proliferation. Priorities include evaluating notice-and-takedown efficacy, advertising transparency improvements, risk assessment outcomes, oversight integration, and procedural shifts in platform governance. Coordinated efforts between researchers, regulators and platforms are needed to address methodological challenges around isolating DSA impacts amidst an evolving EU regulatory landscape, constrained data access from platforms, and difficulties generalizing findings across the sociotechnical diversity of platforms and national contexts in EU Member States.
An Efficient Deep Learning Approach for DNA-Binding Proteins Classification from Primary Sequences
Authors: Ahmed Nosiba Yousif , Alsanousi Wafa Alameen , Hamid Eman Mohammed , Elbashir Murtada K. , Al-Aidarous Khadija Mohammed , Mohammed Mogtaba , Musa Mohamed Elhafiz M.
Published: April 2024

As the number of identified proteins has expanded, the accurate identification of proteins has become a significant challenge in the field of biology. Various computational methods, such as Support Vector Machine (SVM), K-nearest neighbors (KNN), and convolutional neural network (CNN), have been proposed to recognize deoxyribonucleic acid (DNA)-binding proteins solely based on amino acid sequences. However, these methods do not consider the contextual information within amino acid sequences, limiting their ability to adequately capture sequence features. In this study, we propose a novel approach to identify DNA-binding proteins by integrating a CNN with bidirectional long-short-term memory (LSTM) and gated recurrent unit (GRU) as (CNN-BiLG). The CNN-BiLG model can explore the potential contextual relationships of amino acid sequences and obtain more features than traditional models. Our experimental results demonstrate a validation set prediction accuracy of 94% for the proposed CNN-BiLG, surpassing the accuracy of machine learning models and deep learning models. Furthermore, our model is both effective and efficient, exhibiting commendable classification accuracy based on comparative analysis.
Universal hypothesis of autocorrelation function from Krylov complexity
Authors: Zhang Ren , Zhai Hui
Published: April 2024

In a quantum many-body system, autocorrelation functions can determine linear responses nearby equilibrium and quantum dynamics far from equilibrium. In this letter, we bring out the connection between the operator complexity and the autocorrelation function. In particular, we focus on a particular kind of operator complexity called the Krylov complexity. We find that a set of Lanczos coefficients $\{b_{n}\}$
{

b
n

}
computed for determining the Krylov complexity can reveal the universal behaviors of autocorrelations, which are otherwise impossible. When the time axis is scaled by $b_{1}$

b
1

, different autocorrelation functions obey a universal function form at short time. We further propose a characteristic parameter deduced from $\{b_{n}\}$
{

b
n

}
that can largely determine the behavior of autocorrelations at the intermediate time. This parameter can also largely determine whether the autocorrelation function oscillates or monotonically decays in time. We present numerical evidences and physical intuitions to support these universal hypotheses of autocorrelations. We emphasize that these universal behaviors are held across different operators and different physical systems.
Metric localization for lunar rovers via cross-view image matching
Authors: Chen Zihao , Li Kunhong , Li Haoran , Fu Zhiheng , Zhang Hanmo , Guo Yulan
Published: April 2024

Accurate localization is critical for lunar rovers exploring lunar terrain features. Traditionally, lunar rover localization relies on sensor data from odometers, inertial measurement units and stereo cameras. However, localization errors accumulate over long traverses, limiting the rover’s localization accuracy. This paper presents a metric localization framework based on cross-view images (ground view from a rover and air view from an orbiter) to eliminate accumulated localization errors. First, we employ perspective projection to reduce the geometric differences in cross-view images. Then, we propose an image-based metric localization network to extract image features and generate a location heatmap. This heatmap serves as the basis for accurate estimation of query locations. We also create the first large-area lunar cross-view image (Lunar-CV) dataset to evaluate the localization performance. This dataset consists of 30 digital orthophoto maps (DOMs) with a resolution of 7 m/pix, collected by the Chang’e-2 lunar orbiter, along with 8100 simulated rover panoramas. Experimental results on the Lunar-CV dataset demonstrate the superior performance of our proposed framework. Compared to the second best method, our method significantly reduces the average localization error by 26% and the median localization error by 22%.
Experimental studies on the Hartmann tube
Authors: Rathakrishnan E.
Published: April 2024

The effect of tube depth, the separation distance between the tube and nozzle exit, and the nozzle pressure ratio on the characteristics of the flow coming out of the Hartmann tube was studied experimentally. The configuration used in this work consists of an underexpanded sonic jet emanating from a convergent nozzle directed into a closed-ended cylindrical tube of the same diameter (D) as the nozzle exit. The nozzle was operated at two levels of underexpansion corresponding to nozzle pressure ratio (NPR) 3 and 5. The distance (S) from nozzle exit and tube inlet was varied from 0.4D to 4D. Discrete high-amplitude tones (the jet regurgitant, JRG) were produced, only at certain (periodic) intervals (near the shock-cell terminations) of spacing for NPR 3, while for NPR 5 the JRG tones are produced at all points beyond the first shock-cell. For locations other than these, high-frequency tones (screech mode) were observed. The connection between the jet structure and operating modes revealed that the location of standoff shock ahead of the tube with respect to the jet structure plays a dominant role in the observed ‘modes’ rather than the nozzle tube separation. The results reveal that the frequency response of longer tubes in JRG mode approaches their quarter wave frequencies. The high-frequency oscillations observed in the screech mode showed independency with cavity (pipe) depth, contrary to the available literature, the transition between ‘different modes’ oscillation is a function of cavity depth.
Impact of large-scale free-stream turbulence on a pitching airfoil
Authors: Boye ThankGod Enatimi , Djidjeli Kamal , Xie Zheng-Tong
Published: April 2024

This paper investigates the impact of large-scale turbulence on the aerodynamic characteristics of a pitching wind turbine blade at Reynolds number 135 000, whose cross-section is a NACA0012 airfoil with constant chord length. Large-eddy simulations at reduced frequencies,

$k_{red} = 0.05$

and 0.1, were validated against reference data from the literature. An efficient method capable of generating synthetic large-scale turbulence at the inlet was applied by using two streamwise integral length scales

$L_{x} = 1c$

and 1.5

$c$

, which represent energetic turbulence eddies at the height where the wind turbine operates. For

$k_{red}= 0.1$

, the change in the maximum lift coefficient at the dynamic stall angle near the maximum angle of attack is on average 20 % lower and during the downstroke it is on average 22 % lower, compared with the smooth inflow. A higher reduced frequency (

$k_{red} = 0.2$

) apparently does not further change the lift, drag and moment coefficients, and the inflow turbulence disordered leading-edge vortices. The turbulent shear stress and the phase-averaged dispersive shear stress in the wake are of the same magnitude, but with negative and positive signs, respectively, suggesting that the large-scale phase-averaged fluctuations transfer momentum in the opposite direction compared with the turbulent fluctuations, reducing the drag on the suction-side flow, and subsequently increasing the averaged lift coefficient. This demonstrates the critical importance of the large-scale non-turbulent unsteadiness in the wake of a pitching wing.
Nurturing families: A feasibility randomised controlled trial of a whole-family intervention with vulnerable families in Jordan
Authors: Brown Felicity L. , Yousef Hind , Bleile Alexandra C.E. , Mansour Hadeel , Barrett Anna , Ghatasheh Maha , Puffer Eve S. , Mansour Zeinab , Hayef Karam , Kurdi Samer , Ali Qaasim , Tol Wietse A. , El-Khani Aala , Calam Rachel , Abu Hassan Hana , Jordans Mark J.D.
Published: April 2024

Armed conflict and forced displacement can significantly strain nurturing family environments, which are essential for child well-being. Yet, limited evidence exists on the effectiveness of family-systemic interventions in these contexts. We conducted a two-arm, single-masked, feasibility Randomised Controlled Trial (fRCT) of a whole-family intervention with Syrian, Iraqi and Jordanian families in Jordan. We aimed to determine the feasibility of intervention and study procedures to inform a fully-powered RCT. Eligible families were randomised to receive the Nurturing Families intervention or enhanced usual care (1:1). Masked assessors measured outcomes at baseline and endline; primary outcome measures were caregiver psychological distress, family functioning, and parenting practices. Families and implementing staff participated in qualitative interviews at endline. Of the 62 families screened, 60 (98%) were eligible, 97% completed the baseline and 90% completed the endline. Qualitative feedback indicated specific improvements in adolescent well-being, caregiver distress and parenting, and family relationships. Data highlighted high participant engagement and adequate facilitator fidelity and competence. Outcome measures had good psychometric properties (most α > 0.80) and sensitivity to change, with significant changes seen on most measures in the intervention but not control group. Findings indicate the acceptability and feasibility of intervention and study procedures. Subsequent full-scale evaluation is needed to determine effectiveness.
Turbulent flows over porous lattices: alteration of near-wall turbulence and pore-flow amplitude modulation
Authors: Habibi Khorasani Seyed Morteza , Luhar Mitul , Bagheri Shervin
Published: April 2024

Turbulent flows over porous lattices consisting of rectangular cuboid pores are investigated using scale-resolving direct numerical simulations. Beyond a certain threshold which is primarily determined by the wall-normal Darcy permeability,

${{\mathsf{K}}_y}$

, near-wall turbulence transitions from its canonical regime, marked by the presence of streak-like structures, to another marked by the presence of Kelvin–Helmholtz-like (K–H-like) spanwise-coherent structures. The threshold agrees well with that previously established in studies where permeable-wall boundary conditions had been used as surrogates for a porous substrate (Gómez-de Segura & García-Mayoral, J. Fluid Mech., vol. 875, 2019, pp. 124–172). In the smooth-wall-like regime, none of the investigated substrates demonstrate any reduction in drag relative to a smooth-wall flow. At the permeable surface, a notable component of the flow is that which adheres to the pore geometry and undergoes modulation by the turbulent scales of motions due to the interaction mechanism described by Abderrahaman-Elena et al. (J. Fluid Mech., vol. 865, 2019, pp. 1042–1071). Its resulting effect can be quantified in terms of an amplitude modulation (AM) using the approach of Mathis et al. (J. Fluid Mech., vol. 628, 2009, pp. 311–337). This pore-coherent flow component persists throughout the porous substrate, highlighting the importance of a given substrate's microstructure in the presence of an overlying turbulent flow. This geometry-related aspect of the flow is not accounted for when continuum-based models for a porous medium or effective representations of them, such as wall boundary conditions, are used. The intensity of the AM effect is enhanced in the K–H-like regime and becomes strengthened with larger permeability. As a result, structured porous materials may be designed to exploit or mitigate these flow features depending upon the intended application.
MORE ON GALOIS COHOMOLOGY, DEFINABILITY, AND DIFFERENTIAL ALGEBRAIC GROUPS
Authors: LEÓN SÁNCHEZ OMAR , MERETZKY DAVID , PILLAY ANAND
Published: April 2024

As a continuation of the work of the third author in [5], we make further observations on the features of Galois cohomology in the general model theoretic context. We make explicit the connection between forms of definable groups and first cohomology sets with coefficients in a suitable automorphism group. We then use a method of twisting cohomology (inspired by Serre’s algebraic twisting) to describe arbitrary fibres in cohomology sequences—yielding a useful “finiteness” result on cohomology sets.

Applied to the special case of differential fields and Kolchin’s constrained cohomology, we complete results from [3] by proving that the first constrained cohomology set of a differential algebraic group over a bounded, differentially large, field is countable.
Identification and maturation of the metacercaria of Indodidymozoon pearsoni
Authors: Anderson G.R.
Published: April 2024

The metacercaria of Indodidymozoon pearsoni (Digenea: Didymozoidae) is identified by DNA sequencing of second internal transcribed spacer (ITS2) ribosomal DNA and described. Its development into the adult is documented. Morphological features that may assist the matching of didymozoid metacercariae to adults are discussed. Those that may be of greatest use are the size of the oral and ventral suckers and the presence or absence of a chamber at the posterior extremity of the oesophagus.
Fasciola hepatica: an unusual development of redial generations in an isolate of Lymnaea truncatula
Authors: Augot D. , Abrous M. , Rondelaud D. , Dreyfuss G. , Cabaret J.
Published: April 2024

Single-miracidium infections of Lymnaea truncatula by Fasciola hepatica were experimentally carried out to identify the redial generations of this trematode when the larval development was unusual (when the first-appearing mother redia, or R1a redia, died after its exit from the sporocyst). Four parameters were measured in the body and pharyngeal region at weekly intervals. At day 49 post-exposure at 20°C, the body of the second mother rediae (R1b) was significantly longer than that of the subsequent generations, R2a and R2b/R3a (a mean of 3.0 mm instead of 1.0 and 0.9 mm, respectively). The body was significantly wider in the R1b and R2a groups than in the R2b/R3a rediae. The pharyngeal lumen was significantly wider in the R1b group than in the R2a and R2b/R3a rediae (a mean of 48.6 μm instead of 10.8 and 3.3 μm at day 49). The thickness of the pharyngeal wall did not differ in the R1b and R2b/R3a groups, but was significantly lower in the R2a group (19.5 μm instead of 23.0–23.6 at day 49). There was better development of R1b and R2b/R3a rediae in the snails when the R1a redia died, compared with normal larval development (with a living R1a redia).
A kinetic model for Ascaridia galli populations in chickens treated with mixed salts of copper and zinc
Authors: Gabrashanska M. , Teodorova S. , Galvez-Morros M. , Martinez O. Garcia
Published: April 2024

The action of mixed salts of copper and zinc (basic and neutral) on Hisex chickens experimentally infected with Ascaridia galli has been studied. The data show that the lowest host mortality and decrease in body weight gain and the highest reduction in nematode loading occurs in infected chickens treated with basic salts (in comparison with infected chickens, untreated or treated with neutral salts). A mathematical model has been proposed to provide a quantitative interpretation of the observed results. The model solutions of the kinetics of parasite numbers and of the gain in body weight are in a good agreement with the experimental data. One of the kinetic parameters in the model is defined as a phenomenological constant of the host immune response. Its value is determined in the case of infected and untreated chickens.
Phototactic responses of the cercaria of Echinoparyphium recurvatum during phases of sub-maximal and maximal infectivity
Authors: McCarthy A.M.
Published: April 2024

Phototactic responses of cercariae of the echinostome Echinoparyphium recurvatum (Digenea: Echinostomatidae) were investigated during phases of sub-maximal and maximal infectivity using a simple light/dark choice chamber. The phototactic responses of a total of 400 cercariae were examined in 20 replicate experiments during their sub-maxinal infectivity dispersal phase (0.5 h post-emergence from the first intermediate host Lymnaea peregra) and during their maximal infectivity phase (2.5 h post-emergence). Cercariae in the sub-maximal infectivity dispersal phase were found to be positively phototactic, significantly larger numbers of them occurring on the light side of a light/dark choice chamber P < 0.001. Cercariae in the maximal infectivity phase were found to be negatively phototactic, significantly larger numbers of them being found on the dark side of the choice chamber, P < 0.001. This report of ‘phototactic switching’ demonstrated by the cercariae of E. recurvatum from a positively phototactic dispersal phase to a negatively phototactic infection phase constitutes the first record of such behaviour in the cercaria of an echinostome.
Attachment tests of Pasteuria penetrans to the cuticle of plant and animal parasitic nematodes, free living nematodes and srf mutants of Caenorhabditis elegans
Authors: de Gives P. Mendoza , Davies K.G. , Morgan M. , Behnke J.M.
Published: April 2024

Populations of Pasteuria penetrans isolated from root-knot nematodes (Meloidogyne spp.) and cyst nematodes (Heterodera spp.) were tested for their ability to adhere to a limited selection of sheathed and exsheathed animal parasitic nematodes, free living nematodes, including Caenorhabditis elegans wild type and several srf mutants, and plant parasitic nematodes. The attachment of spores of Pasteuria was restricted and no spores were observed adhering to any of the animal parasitic nematodes either with or without their sheath or to any of the free living nematodes including C. elegans and the srf mutants. All spore attachment was restricted to plant parasitic nematodes; however, spores isolated from cyst nematodes showed the ability to adhere to other genera of plant parasitic nematodes which was not the case with spores isolated from root-knot nematodes. The results are discussed in relationship to cuticular heterogeneity.
Morphology of inhibited larvae of the bovine lungworm Dictyocaulus viviparus
Authors: Samson-Himmelstjerna G. von , Schnieder T.
Published: April 2024

Some morphological features of inhibited fourth stage (L4) and fourth moult larvae (4M) of the bovine lungworm Dictyocaulus viviparus are described. Inhibition was induced by maintaining the third stage larvae (L3) for 6 weeks at 4°C. Inhibited fourth stage (L4) and fourth moult larvae (4M) were collected by perfusion of the lungs of experimentally infected calves after necropsy at 15 and 68 days post infection (d.p.i.), respectively. Inhibited 4M, isolated at 68 d.p.i., were about ten times larger than inhibited L4 isolated at 15 d.p.i.
Thermal tolerance of Hymenolepis diminuta eggs does not limit the parasite's distribution
Authors: Pappas P.W. , Rutherford K.H. , Barley A.J.
Published: April 2024

Eggs of the tapeworm, Hymenolepis diminuta, and adults of the beetle, Tenebrio molitor, were incubated at high and low temperatures. The tapeworm's eggs survived at higher and lower temperatures and for longer periods of time than did adult beetles, indicating that the thermal tolerance of the eggs does not limit the parasite's distribution.
Microhabitat characteristics and reproductive status of male Euchordodes nigromaculatus (Nematomorpha)
Authors: Thomas F. , Schmidt-Rhaesa A. , Poulin R.
Published: April 2024

In a sample of 61 free-living, postparasitic male Euchordodes nigromaculatus collected from a mountain stream in New Zealand, we found that only large males are found in areas of high current velocity. Thirty-five of the 61 males still contained gametes; these worms were found in wider, deeper, and slower-flowing parts of the stream relative to worms that had released their gametes. These results suggest that the physical characteristics of the immediate microhabitat of male worms can determine their probability of mating.
Pomphorhynchus laevis in its intermediate host Echinogammarus stammeri in the River Brenta, Italy
Authors: Dezfuli B.S. , Rossetti E. , Bellettato C.M. , Maynard B.J.
Published: April 2024

Infection rates of larval Pomphorhynchus laevis Mu¨ller, 1776 (Acanthocephala) were studied in its intermediate host Echinogammarus stammeriS. Karaman, 1931 (Amphipoda). Crustaceans were collected monthly, from July 1990 to July 1997, at two sites on the River Brenta (northern Italy). Of over 50,000 E. stammeri examined, more than 24% were parasitized with P. laevis larvae. The differences in the prevalence of infection between the two stations were significant. The intensity of infection varied from one to 15 acanthocephalans per host. Amphipods with multiple infections constituted 28–32% of each monthly sample. During the 7 years of investigation, the prevalence of infection typically reached its highest and lowest levels in the summer and spring months, respectively. Acanthocephalan larvae showed no preference for host sex. Infected ovigerous females of E. stammeri were found carrying eggs or juveniles in their brood pouches, but had fewer and smaller eggs. Pomphorhynchus laevis larvae co-occurred with Acanthocephalus clavula (Dujardin, 1845) and also with the tapeworm Cyathocephalus truncatus (Pallas, 1781) in the same host.
The ability of the nematode-trapping fungus Duddingtonia flagrans to reduce the transmission of
Authors: Fernández A.S. , Larsen M. , Nansen P. , Henningsen E. , Grønvold J. , Wolstrup J. , Henriksen S.A. , Bjørn H.
Published: April 2024

The ability of two isolates of the nematode-trapping fungus Duddingtonia flagrans to reduce the numbers of gastrointestinal nematode larvae on herbage was tested in three plot studies. Artificially prepared cow pats containing Ostertagia ostertagi eggs, with and without fungal spores, were deposited on pasture plots two or three times during the grazing season in 1995, 1996 and 1997. The herbage around each pat was sampled fortnightly over a period of 2 months and the number of infective larvae was recorded. At the end of the sampling period, the remainder of the faecal pats was collected to determine the wet weight, dry weight, and content of organic matter. The infective larvae remaining in the pats were extracted. Faecal cultures showed that both fungal isolates significantly reduced the number of infective larvae. Significantly fewer larvae were recovered from herbage surrounding fungus-treated pats compared with control pats in all three experiments, reflecting the ability of the fungus to destroy free-living larval stages in the faecal pat environment. After 8 weeks on pasture there were no differences between control and fungus-treated pats with respect to wet weight, dry weight, and organic matter content. This indicates that the degradation of faeces was not negatively affected by the presence of the fungus.
Ultrastructural aspects of feeding and secretion–excretion by the equine parasite Strongylus vulgaris
Authors: Mobarak M.S. , Ryan M.F.
Published: April 2024

Light, scanning, and transmission electron microscopy were employed to provide further data on the putative origins of the immunogenic secretory–excretory product (ESP) of Strongylus vulgaris (Looss 1900). The sharply delineated but superficial attachment to the equine caecum by the mouth leaves behind an oval area devoid of epithelial cells. Attachment does not extend deeply enough to reach the muscularis mucosa layer of the equine intestine. The progressive digestion of the ingested plug of tissue (epithelial cells, blood cells and mucous) was visualized. The coelomocytes, floating cells and membranous structures located in the pseudocoelom and intimately associated with the digestive, excretory and reproductive systems, and with the somatic muscles are described. The secretory–excretory system comprises two, ventrally-located, secretory–excretory glands connected to tubular elements. These glands synthesize granules of various sizes and densities that are delineated.
The dynamics of nematode transmission in the red grouse (Lagopus lagopus scoticus) : studies on the recovery of Trichostrongylus tenuis larvae from vegetation
Authors: Saunders L.M. , Tompkins D.M. , Hudson P.J.
Published: April 2024

Attempts to recover the infective third-stage larvae of Trichostrongylus tenuis from heather (Calluna vulgaris) vegetation in the field are rarely successful because the larvae may be: (i) concealed within heather leaflets; (ii) concentrated in dew droplets which are lost from the plants upon sampling; or (iii) simply highly aggregated in the field. Heather plants were exposed to T. tenuis larvae in the laboratory and kept under suitable conditions for larval migration. Few larvae were found in dew droplets or concealed within heather leaflets; most larvae were recovered from the plant surface. This suggests that the low larval recovery from vegetation in the field simply reflects a highly aggregated distribution of few larvae. In a second experiment, the efficiency with which infective larvae migrate up the structurally complex heather plants was compared with migration up two control plant species with simpler structures: a monocotyledon, wheat, and a dicotyledon, hebe. After constant exposure, significantly more larvae were recovered from heather than from either of the control plants. This implies that the structural complexity of heather causes no problems for the infective larvae.
Survival and infectivity of Hypoderaeum conoideum and Euparyphium albuferensis cercariae under laboratory conditions
Authors: Toledo R. , Muñoz-Antoli C. , Pérez M. , Esteban J.G.
Published: April 2024

The survival characteristics of the cercariae of Hypoderaeumconoideum and Euparyphiumalbuferensis (Trematoda: Echinostomatidae) at 20°C and 30°C are described, and the age dependency of their infectivity at 20°C is studied to determine their respective transmission efficiencies. Cercarial survival was found to be age-dependent and was higher at 20°C. For both cercariae, the maximum life-span was 26 h at 20°C and 16 h at 30°C, and their respective times to 50% mortality were similar at each temperature. Both cercariae seem to be well adapted to transmission in their natural habitat, though cercarial infectivity of H. conoideum was higher than that of E. albuferensis, this being correlated with their prevalences in nature. The age-dependency of cercarial survival may be related to steadily diminishing endogenous energy levels, though the delay in attaining maximum infectivity suggests that other factors not related to energy considerations are involved in the delimitation of the cercarial infective period. However, this latter observation may constitute an adaptative mechanism allowing cercarial dissemination.
Oncospheres of Taenia solium and T. saginata asiatica develop into metacestodes in normal and immunosuppressed mice
Authors: Wang I.C. , Ma Y.X. , Guo J.X. , Chung W.C. , Lu S.C. , Ito A. , Fan P.C.
Published: April 2024

Normal and immunosuppressed mice were infected with oncospheres of Taenia saginata asiatica and T. solium. Although normal ICR mice were not susceptible to these two parasites, cysticerci were recovered from the immunosuppressed ones following venous injection. For T. s. asiatica, immunosuppressed ICR mice had an infection rate of 12.5% and six cysticerci of this parasite were recovered from three males. After injection of T. solium oncospheres, a high infection rate of 57% was obtained and 23 cysticerci were collected from 13 male immunosuppressed ICR mice. The immunosuppressed C57 mice had the highest infection rate (100%) and cysticercus recovery rate (2.4%) for T. solium. The infection rate and cysticercus recovery rate in six normal C57 mice were 40% and 3% respectively. The immunosuppressed ICR, Balb/c and C3H mice were also susceptible to T. s. asiatica.
Diagnosis of Strongyloides stercoralis by acid-fast staining
Authors: Siddiqui A.A. , Gutierrez C. , Berk S.L.
Published: April 2024

Faecal smears of patients and Strongyloides stercoralis obtained from dogs were acid-fast stained with Kinyoun and Auramine O staining procedures. Both larval (rhabditiform and filariform) and adult parasites were effectively stained by these methods. Acid-fast staining can serve as a useful procedure for diagnosing strongyloidiasis.
Paramphistomum daubneyi and Fasciola hepatica: the prevalence of natural or experimental infections in four species of freshwater snails in eastern France
Authors: Degueurce F. , Abrous M. , Dreyfuss G. , Rondelaud D. , Gevrey J.
Published: April 2024

Parasitological investigations were performed in July and September–October 1997 in six farms located in the department of Saône et Loire (eastern France) to determine the prevalence of natural infections with Paramphistomum daubneyi and Fasciola hepatica in four species of freshwater snails. Cercaria-containing rediae of P. daubneyi and/or F. hepatica were found in Lymnaea palustris (one snail only) and Lymnaea truncatula. Some living sporocysts and immature rediae were noted in Lymnaea ovata (P. daubneyi or F. hepatica) and in Physa acuta (P. daubneyi only). The prevalence of each trematode infection was often less than 10%. Experimental infections of juvenile and preadult snails (1 and 4 mm in height, respectively) were also performed to test the susceptibility of these four snail species to P. daubneyi, either singly or in combination with F. hepatica. Both 1 and 4 mm high L. truncatula could sustain the full development of P. daubneyi, whether in single or double infections. In L. palustris dually exposed to both trematodes, cercaria-containing rediae of P. daubneyi were found in one juvenile and one preadult snails, while immature infections were noted in ten juvenile and two preadult snails. The overall prevalence of P. daubneyi infection in L. palustris was 11.1% in juvenile snails and 2.1% in preadults. Larval forms of P. daubneyi and F. hepatica were only noted in dually-exposed juvenile L. ovata and P. acuta. In L. ovata, mature and immature rediae of F. hepatica were detected in 17.6% of snails, while immature rediae of P. daubneyi were noted in 4.4% of snails. In P. acuta, only immature infections were detected (5.1% of snails with P. daubneyi, and 1.2% with F. hepatica). These results demonstrated that Lymnaea species other than L. truncatula could sustain the full development of P. daubneyi and that immature larvae of this trematode might be found in naturally- or experimentally-infected L. ovata and P. acuta.
The parasite community infecting flounders, Platichthys flesus, in the tidal Thames
Authors: El-Darsh H.E.M. , Whitfield P.J.
Published: April 2024

The composition of the parasite fauna of the flounder, Platichthys flesus, retrieved from two locations in the tidal Thames is described in detail for the first time. The combined parasite species list of the flounders from Lots Road in the upper tideway and West Thurrock in the middle tideway consisted of one protozoan (Glugea stephani), one monogenean (Gyrodactylus sp.), four larval digeneans (Cryptocotyle concava, Timoniella imbutiforme, T. praeterita, and Labratrema minimus), five adult digeneans (Derogenes varicus, Lecithaster gibbosus, Podocotyle sp., Plagioporus varius, and Zoogonoides viviparus), one larval cestode (unidentified tetraphyllidean), one or possibly more larval nematodes (unidentified) plus five adult nematodes (Capillaria sp., Cucullanus heterochrous, C. minutus, Contracaecum sp. and Goezia sp.), two acanthocephalans (Pomphorhynchus laevis and Acanthocephalus anguillae), three copepods (Lepeophtheirus pectoralis, Acanthochondria sp. and Lernaeocera branchialis), and one mollusc (unidentified glochidia). The overall parasite community of flounders from Lots Road and West Thurrock were compared in terms of species richness and diversity. The parasite community in flounders from the former location in the upper tideway was found to be less diverse than that of its counterpart at West Thurrock in the middle estuary. The component community of Lots Road flounders was dominated by the acanthocephalan Pomphorhynchus laevis.
Schistosome cercariae as the causative agent of swimmer's itch in Iceland
Authors: Kolářová L. , Skirnisson K. , Horák P.
Published: April 2024

During late summer in 1995 to 1997, repeated outbreaks of maculopapular skin eruptions were noted on the legs of children after wading in the pond in the Family Park in Laugardalur, Reykjavík, Iceland. Clinical symptoms developing on the legs resembled those of cercarial dermatitis. An examination of Lymnaea peregra snails from this pond and from the adjacent Lake Tjornin resulted in detection of previously undescribed schistosome cercariae. This is the first report of schistosomes in Iceland and also the most northern occurrence of these parasites in Europe.
An enhanced humoral immune response against the swimbladder nematode, Anguillicola crassus, in the Japanese eel, Anguilla japonica, compared with the European eel, A. anguilla
Authors: Nielsen M.E.
Published: April 2024

The humoral immune response in the two eel species, Anguilla japonica and Anguilla anguilla against two fractions of antigens in Anguillicola crassus were studied.Within species, both eel species showed significantly elevated titres compared with controls when immunized with antigens from Anguillicola crassus.In interspecific comparison, Anguilla japonicashowed significantly elevated titres in comparison with Anguilla anguilla. Immunization of Anguilla anguillacaused a significantly decrease in the plasma levels of protein in comparison with control fish and all groups of Anguilla japonica. In contrast, Anguilla japonica showed significantly lower plasma levels of Ig in all groups compared with Anguilla anguilla.The different susceptibilities to Anguillicola crassus between the natural host, Anguilla japonica, and the naı¨ve, Anguilla anguilla, is partly due to differences in the ability of the two eel species to mount a humoral immune response.
Hepatic [2-13C]acetate metabolism by jirds infected with Echinococcus multilocularis
Authors: Schoen J. , Novak M. , Blackburn B.J.
Published: April 2024

Carbon-13 decoupled 1H spin echo NMR spectroscopy, with and without population inversion, was used to study carbon flow between the host, Meriones unguiculatus, and the parasite, Echinococcus multilocularis. This was accomplished by monitoring [2-13C]acetate metabolism in the liver of jirds infected with metacestodes of this parasite. Thirty minutes after injection of labelled acetate solution into the portal vein, 13C enrichment was observed in hepatic acetate, β–hydroxybutyrate, succinate, alanine, lactate and glucose. For E. multilocularis cysts, at this time,13C enrichment was observed in the same metabolites as in livers and, in addition, citrate. At 120 min there was a significant decrease in the amount of label present in all hepatic metabolites whereas more label was found in the majority of the parasite metabolites. The results confirm that exogenous acetate, through randomization of the 13C in biochemical pathways of host liver, ends up in hepatic glucose. As this biosynthetic route is not available to the parasite, the presence of 13C enriched glucose in the cysts clearly indicates that the parasite is siphoning off glucose that is newly synthesized by the host. At 120 min some of this labelled glucose was stored in parasite glycogen whereas some of it had been catabolized to succinate, alanine, lactate and acetate, end products which are excreted back into the host.
Biochemical profiles of hydatid cyst fluids of Echinococcus granulosus of human and animal origin in Libya
Authors: Shaafie I.A. , Khan A.H. , Rambabu K.
Published: April 2024

A comparative study on the biochemical parameters in hydatid cyst fluids of sheep, goats, camels, cattle and human cystic forms of Echinococcus granulosus has been made in Libya. Quantitative variations in the levels of sodium, potassium, calcium, cholesterol, glucose, urea, creatinine and gamma glutamyl transpeptidase (γGT) were found in the cystic fluids of different host origins although these differences were statistically insignificant compared with the hydatid fluids of sheep. However, the concentration of triglycerides and proteins were significantly elevated in the cyst fluids of sheep compared with the other fluids studied. Similarities in the biochemical composition of different hydatid cyst fluids suggest the existence of sheep strains of E. granulosus in human and other domestic animal intermediate hosts in Libya.
Nucella lapillus as a paratenic host for Maritrema arenaria
Authors: McCarthy H.O. , Irwin S.W.B. , Fitzpatrick S.M.
Published: April 2024

Metacercariae of the microphallid trematode Maritrema arenaria are found in the shore barnacle Semibalanoides balanoides which is heavily predated by the dog whelk, Nucella lapillus. This study demonstrated that, under experimental and natural conditions, M. arenaria metacercarial cysts were ingested by N. lapillus and the metacercariae retained their viability while passing through the molluscs' digestive systems. Dog whelks are a known food source for numerous bird species, leading to the conclusion that they may act as paratenic hosts of M. arenaria. The strategic importance of the adoption by M. arenaria of N. lapillus as a paratenic host is discussed.
Patterns in metazoan parasite communities of some oyster species
Authors: Aguirre-Macedo M.L. , Kennedy C.R.
Published: April 2024

Metazoan parasite communities of Crassostrea gigas and Ostrea edulis from Great Britain, Crassostrea virginica from Mexico, and Saccostrea commercialis from Australia are described and summarized in terms of species composition, species richness, total number of individuals and dominance. Metazoan parasite communities in all host species were composed of turbellarians and the metacercarial stage of digeneans, with the exception of S. commercialis where only metacercariae were found. Arthropods, including one copepod and one mite species, were present only in British oyster species. All metazoan parasite communities of oysters had few species and low density of individuals. Richest communities were found in C. virginica at both component and infracommunity level. The least diverse component community occurred in S. commercialis. Infracommunities in O. edulis and S. commercialis never exceeded one species per host. The host response against parasites is suggested as the principal factor responsible for depauperate parasite communities of oysters. Environmental factors characteristic of tropical latitudes are likely to have enhanced both the number of species and the densities of parasites per host in the infracommunities of C. virginica.