Ability Of Parasite Research Articles

Expression Patterns of Plasmodium falciparum Clonally Variant Genes at the Onset of a Blood Infection in Malaria-Naive Humans.

ABSTRACTClonally variant genes (CVGs) play fundamental roles in the adaptation of Plasmodium falciparum to fluctuating conditions of the human host. However, their expression patterns under the natural conditions of the blood circulation have been characterized in detail for only a few specific gene families. Here, we provide a detailed characterization of the complete P. falciparum transcriptome across the full intraerythrocytic development cycle (IDC) at the onset of a blood infection in malaria-naive human volunteers. We found that the vast majority of transcriptional differences between parasites obtained from the volunteers and the parental parasite line maintained in culture occurred in CVGs. In particular, we observed a major increase in the transcript levels of most genes of the pfmc-2tm and gbp families and of specific genes of other families, such as phist, hyp10, rif, or stevor, in addition to previously reported changes in var and clag3 gene expression. Increased transcript levels of individual pfmc-2tm, rif, and stevor genes involved activation in small subsets of parasites. Large transcriptional differences correlated with changes in the distribution of heterochromatin, confirming their epigenetic nature. Furthermore, the similar expression of several CVGs between parasites collected at different time points along the blood infection suggests that the epigenetic memory for multiple CVG families is lost during transmission stages, resulting in a reset of their transcriptional state. Finally, the CVG expression patterns observed in a volunteer likely infected by a single sporozoite suggest that new epigenetic patterns are established during liver stages.

Ecological niche models of biotic interactions predict increasing pest risk to olive cultivars with changing climate

AbstractSimple, single‐species approaches in distributional ecology leave open questions of possible roles of biotic interactions. We sought to understand impacts of climate change on current and future potential distributions of Olea europaea sensu lato (host) and Bactrocera oleae (parasite) in Europe, the Middle East, and Africa (EMEA), taking into account potential interspecific interactions. We used ecological niche modeling approaches: For biotic interactions, an initial host model was incorporated into the calibration of the parasite model and an initial parasite model was incorporated into calibration of the host model, as host and parasite populations may respond to the presence of the other species. Absence of olive fruits could reduce the flight ability of the fly parasite, whereas presence of the parasite may make a site less suitable for the olives. The host model was improved by inclusion of the parasite information; the converse was not true for the parasite model. Our results anticipated a significant reduction in the potential distribution of Olea europeae in Africa and Europe under future climate scenarios; in contrast, future climates appear more broadly favorable for the parasite species, which poses new and increasing risks for olive cultivation in the Mediterranean region.

Evaluación de la seroprevalencia de toxoplasma gondii en poblaciones de riesgo: una revisión narrativa

Objective To elaborate a narrative review in order to evaluate the prevalence of toxoplasmosis in high-risk population groups with a global perspective to promote the development of strategies for the prevention and management of the infection among the referred groups. Introduction: Toxoplasmosis is an infection present in both humans and animals, considered a public health problem that is distributed globally. Among the population groups with a higher risk of developing alterations when acquiring this zoonosis are immunocompromised individuals, newborns born to mothers infected during pregnancy and women of childbearing age; the latter are considered to be at high risk due to the parasite's ability to cross the placental barrier. Many studies have been published regarding the seroprevalence of this infection, but there is insufficient information regarding the decrease or increase of the pathology in populations considered at risk. Methodology: A searched was carried out for articles in Spanish, English and Portuguese in the databases Google Scholar, ScienceDirect, PubMed, Scopus, Springer, ProQuest, Epistemonikos and Scielo, with a range of years between 2005 and 2020, using the keywords: newborn, immunosuppression, pregnant women, toxoplasmosis and prevalence. Results: The observed prevalence of toxoplasmosis in newborns ranged from 0.06% to 93% for IgG and IgM antibodies. The reported prevalence of IgG anti-Toxoplasma gondii antibodies in women of childbearing age ranged from 18% to 88.7%, and of IgM anti-Toxoplasma gondii antibodies ranged from 1.34% to 30.9% and finally in the group of people with Immunosuppression the prevalence of IgG anti-Toxoplasma gondii antibodies ranged from 8.8% to 94.3% for IgG and IgM antibodies. Conclusion: the routes of transmission of this infection are known and the population groups at risk are identified; however, it has not been possible to reduce the seroprevalence in the different countries, which indicates that it is necessary to create more adequate strategies to educate individuals and drastically reduce the presence of this zoonosis.

Impairment of effector molecules response in diabetes induces susceptibility to Leishmania amazonensis infection

Type 2 Diabetes is a chronic disease resulting from insulin dysfunction that triggers a low-grade inflammatory state and immune impairment. Leishmaniasis is an infectious disease characterized by chronic inflammation resulted from the parasite's immunomodulation ability. Thus, due to the delicate immune balance required in the combat and resistance to Leishmania infection and the chronic deregulation of the inflammatory response observed in type 2 diabetes, we evaluated the response of PBMC from diabetic patients to in vitro Leishmania amazonensis infection. For that, peripheral blood was collected from 25 diabetic patients and 25 healthy controls matched for age for cells extraction and subsequent experimental infection for 2 or 24 h and analyzed for phagocytic and leishmanicidal capacity by optical microscopy, oxidative stress by GSSG generation, labeling of intracellular mediators by enzyme-Linked immunosorbent assay, and cytokines measurement with cytometric beads array technique. We found that the diabetic group had a higher percentage of infected cells and a greater number of amastigotes per cell. Also, even inducing NF-kB phosphorylation and increasing TNF production after infection, cells from diabetic patients were unable to downregulate NRF2 and generate oxidative stress, which may be associated with the exacerbated levels of IL-6 observed. PBMC of diabetic individuals are more susceptible to infection by L. amazonensis and fail to control the infection over time due to the inability to generate effector microbicidal molecules.

Transformation of an artificial microRNA to soybean (Glycine max (L.) Merr.) to reduce the parasitism of Meloidogyne incognita

Effectors are specific proteins secreted by nematodes into plant cells that facilitate their parasitism to host plants. Inactivation of these effectors could reduce the parasitic ability of nematodes on plants and the damage caused by nematodes. Gene Minc14137encodes an effector unknown function that is cloned from the Meloidogyne incognita. Artificial microRNAs capable of inactivating the gene Minc14137 were synthesised and inserted into an expression vector in soybean. This construct was transformed into the soybean cotyledon node mediated by Agrobacterium tumefaciens and regenerated transgenic plants. Copy number and the expression level of miRNA in T0 transgenic plants were determined by the qPCR technique. In T1 transgenic soybean plants, the pathogenic ability of root-knot nematode is reduced by 44.6-50.5% compared to the control plants. Results show that effector MINC14137 could play an important role in the parasitism of Meloidogyne incognita.

A survey of sheep dicrocoeliosis in Sulaymaniyah slaughterhouse, northern Iraq in 2013-2014.

Dicrocoelium dendriticum is a helminth which lives in the bile ducts and gall bladder of mammalian definitive hosts. Dicrocoeliosis is thought to be endemic in some countries and it has an increasing prevalence in Northern Iraq, potentially due to increased importation of infected animals, particularly sheep, in high numbers from neighboring countries. The parasite's ability to infect rodents, wild animals, livestock and humans means this parasite is of significant interest in veterinary and human medicine. While D. dendriticum causes relatively mild clinical disease in animals, infection leads to liver condemnation at slaughter and subsequent economic losses to farmers. In this study, the livers of 91,486 sheep slaughtered at Sulaymaniyah New Slaughterhouse (Northern Iraq) were visually inspected for D. dendriticum infection between November 2013 and March 2014, with 1269 livers rejected due to D. dendriticum in this period, representing 29.4% of all condemned livers. The highest rate of rejection due to D. dendriticum infection was seen in December, possibly linked to increased numbers of intermediate host snails during the wet season. Routine inspection of condemned livers revealed adult flukes of D. dendriticum and eggs were seen in the faeces of imported sheep, indicating these animals may be a vector for introduction of D. dendriticum to this region. Due to the complex life cycle and wide range of animals which it infects, we cannot establish the exact route of introduction into Iraq; however, our study suggests that slaughterhouse workers, farmers and local health authorities should be aware of the presence of D. dendriticum, and the potential risks it represents to both human and animal health. Our data also suggest that some level of quarantine or border checks may be useful to prevent further introduction of D. dendriticum or other pathogens into Iraq, although this may prove difficult until accurate diagnostic assays are developed.

Right place, right time: Environmental sensing and signal transduction directs cellular differentiation and motility in Trypanosoma brucei.

Trypanosoma brucei and other African trypanosomes are vector-borne parasites that cause substantial human suffering across sub-Saharan Africa. The T. brucei life cycle is punctuated by numerous developmental stages, each occurring in a specific environmental niche and characterized by a unique morphology, metabolism, surface protein coat, and gene expression profile. The environmental cues and signaling pathways that drive transitions between these stages remain incompletely understood. Recent studies have started to fill this gap in knowledge. Likewise, several new studies have expanded our understanding of parasite movement through specific tissues and the parasite's ability to alter movement in response to external cues. Life cycle stage differentiation and motility are intimately integrated phenomena, as parasites must be at the right place (i.e., within a specific environmental milieu) at the right time (i.e., when they are appropriately staged and preadapted for perceiving and responding to signals) in order to complete their life cycle. In this review, we highlight some of the recent work that has transformed our understanding of signaling events that control parasite differentiation and motility. Increased knowledge of T. brucei environmental sensing and signal transduction advances our understanding of parasite biology and may direct prospective chemotherapeutic and transmission blockade strategies that are critical to eradication efforts.

What do the terms resistance, tolerance, and resilience mean in the case of Ostrea edulis infected by the haplosporidian parasite Bonamia ostreae

The decline of the European flat oyster Ostrea edulis represents a loss to European coastal economies both in terms of food security and by affecting the Good Environmental Status of the marine environment as set out by the European Council’s Marine Strategy Framework Directive (2008/56/EC). Restoration of O. edulis habitat is being widely discussed across Europe, addressing key challenges such as the devastating impact of the haplosporidian parasite Bonamia ostreae. The use of resistant, tolerant, or resilient oysters as restoration broodstock has been proposed by restoration practitioners, but the definitions and implications of these superficially familiar terms have yet to be defined and agreed by all stakeholders. This opinion piece considers the challenges of differentiating Bonamia resistance, tolerance, and resilience; challenges which impede the adoption of robust definitions. We argue that, disease-resistance is reduced susceptibility to infection by the parasite, or active suppression of the parasites ability to multiply and proliferate. Disease-tolerance is the retention of fitness and an ability to neutralise the virulence of the parasite. Disease-resilience is the ability to recover from illness and, at population level, tolerance could be interpreted as resilience. We concede that further work is required to resolve practical uncertainty in applying these definitions, and argue for a collaboration of experts to achieve consensus. Failure to act now might result in the future dispersal of this disease into new locations and populations, because robust definitions are important components of regulatory mechanisms that underpin marine management.

Biological traits of Cosmocomoidea annulicornis (Hymenoptera: Mymaridae), an egg parasitoid of the sharpshooter Tapajosa rubromarginata (Hemiptera: Cicadellidae), a vector of Xylella fastidiosa in citrus orchards

The parasitic ability of Cosmocomoidea annulicornis (Hymenoptera: Mymaridae) was tested on eggs of the sharpshooter Tapajosa rubromarginata (Hemiptera: Cicadellidae), vector of the bacterium Xylella fastidiosa that causes citrus variegated chlorosis (CVC), among other plant diseases. In the present study, we evaluated biological traits of C. annulicornis such as parasitism and emergence rates, developmental time, longevity and sex ratio in laboratory conditions on leaves of Citrus aurantium, C. limon, Zea mays and Sorghum halepense. In addition, the functional response of C. annulicornis on host egg masses laid on C. aurantium leaves was studied and new distribution sites of the parasitoid in Argentina are reported. The overall parasitism of C. annulicornis was 49.20 ± 2.90%. Of those parasitized eggs, 83.30 ± 6.51% adults emerged. Parasitism of C. annulicornis was significantly lower in host eggs laid on S. halepense and developmental time was longer in C. limon compared to the other host plant species tested. In all host plant species tested, females developed faster than males. Individuals lived on average 5.94 ± 0.23 days and statistically significant differences were found between the longevity of females and males. Sex ratio of parasitoids was balanced in all host plant species tested, excepted for maize plants, in which sex ratio was female biased. Cosmocomoidea annulicornis females exhibited a type III functional response, indicating a greater searching efficiency at high host densities compared to low densities. Previous reports of field parasitism in combination with our results of C. annulicornis performance on eggs of T. rubromarginata are indicators of a potential biological control agent against the vector of X. fastidiosa, though further studies are needed regarding its biology.

Symbiotic bracovirus of a parasite manipulates host lipid metabolism via tachykinin signaling.

Parasites alter host energy homeostasis for their own development, but the mechanisms underlying this phenomenon remain largely unknown. Here, we show that Cotesia vestalis, an endoparasitic wasp of Plutella xylostella larvae, stimulates a reduction of host lipid levels. This process requires excess secretion of P. xylostella tachykinin (PxTK) peptides from enteroendocrine cells (EEs) in the midgut of the parasitized host larvae. We found that parasitization upregulates PxTK signaling to suppress lipogenesis in midgut enterocytes (ECs) in a non-cell-autonomous manner, and the reduced host lipid level benefits the development of wasp offspring and their subsequent parasitic ability. We further found that a C. vestalis bracovirus (CvBV) gene, CvBV 9–2, is responsible for PxTK induction, which in turn reduces the systemic lipid level of the host. Taken together, these findings illustrate a novel mechanism for parasite manipulation of host energy homeostasis by a symbiotic bracovirus gene to promote the development and increase the parasitic efficiency of an agriculturally important wasp species.

Natural history of extraparenchymal neurocysticercosis

In patients affected by neurocysticercosis (NCC), the extraparenchymal location of the parasites generates the most severe form of the disease. Due to the difficulty in its diagnosis and management, there are still many questions; in particular, the natural history of parasites at this location is not well known. We included 21 patients with vesicular extraparenchymal NCC who had not received treatment for at least 18months. We collected their demographic and clinical data, compared their imaging studies at the beginning and the end of the period without treatment and classified the patients, taking into account the evolution of their parasitic burden. A total of 10 men and 11 women were included. Patients had undergone a period of 63±48months without treatment. During this period, 8 patients (38.1%) showed an increase, 7 (33.3%) a decrease and 6 (28.6%) showed no change in parasite burden. The natural history of extraparenchymal cysticerci is heterogeneous. The results show the ability of parasites to survive for a long time in the extraparenchymal location and explain the chronicity of the disease in some patients. The links between these findings and the difficulties in the therapeutic management of extraparenchymal NCC patients should be studied.

TgIF2K-B Is an eIF2α Kinase in Toxoplasma gondii That Responds to Oxidative Stress and Optimizes Pathogenicity.

Toxoplasma gondii is an obligate intracellular parasite that persists in its vertebrate hosts in the form of dormant tissue cysts, which facilitate transmission through predation. The parasite must strike a balance that allows it to disseminate throughout its host without killing it, which requires the ability to properly counter host cell defenses. For example, oxidative stress encountered by Toxoplasma is suggested to impair parasite replication and dissemination. However, the strategies by which Toxoplasma mitigates oxidative stress are not yet clear. Among eukaryotes, environmental stresses induce the integrated stress response via phosphorylation of a translation initiation factor, eukaryotic initiation factor 2 (eIF2). Here, we show that the Toxoplasma eIF2 kinase TgIF2K-B is activated in response to oxidative stress and affords protection. Knockout of the TgIF2K-B gene, Δtgif2k-b, disrupted parasite responses to oxidative stresses and enhanced replication, diminishing the ability of the parasite to differentiate into tissue cysts. In addition, parasites lacking TgIF2K-B exhibited resistance to activated macrophages and showed greater virulence in an in vivo model of infection. Our results establish that TgIF2K-B is essential for Toxoplasma responses to oxidative stress, which are important for the parasite's ability to establish persistent infection in its host.IMPORTANCEToxoplasma gondii is a single-celled parasite that infects nucleated cells of warm-blooded vertebrates, including one-third of the human population. The parasites are not cleared by the immune response and persist in the host by converting into a latent tissue cyst form. Development of tissue cysts can be triggered by cellular stresses, which activate a family of TgIF2 kinases to phosphorylate the eukaryotic translation initiation factor TgIF2α. Here, we establish that the TgIF2 kinase TgIF2K-B is activated by oxidative stress and is critical for maintaining oxidative balance in the parasite. Depletion of TgIF2K-B alters gene expression, leading to accelerated growth and a diminished ability to convert into tissue cysts. This study establishes that TgIF2K-B is essential for the parasite's oxidative stress response and its ability to persist in the host as a latent infection.

Avian Malaria and Related Parasites from Resident and Migratory Birds in the Brazilian Atlantic Forest, with Description of a New Haemoproteus Species.

Determining the prevalence and local transmission dynamics of parasitic organisms are necessary to understand the ability of parasites to persist in host populations and disperse across regions, yet local transmission dynamics, diversity, and distribution of haemosporidian parasites remain poorly understood. We studied the prevalence, diversity, and distributions of avian haemosporidian parasites of the genera Plasmodium, Haemoproteus, and Leucocytozoon among resident and migratory birds in Serra do Mar, Brazil. Using 399 blood samples from 66 Atlantic Forest bird species, we determined the prevalence and molecular diversity of these pathogens across avian host species and described a new species of Haemoproteus. Our molecular and morphological study also revealed that migratory species were infected more than residents. However, vector infective stages (gametocytes) of Leucocytozoon spp., the most prevalent parasites found in the most abundant migrating host species in Serra do Mar (Elaenia albiceps), were not seen in blood films of local birds suggesting that this long-distance Austral migrant can disperse Leucocytozoon parasite lineages from Patagonia to the Atlantic Forest, but lineage sharing among resident species and local transmission cannot occur in this part of Brazil. Our study demonstrates that migratory species may harbor a higher diversity and prevalence of parasites than resident species, but transportation of some parasites by migratory hosts may not always affect local transmission.

First Report on Megaselia scalaris Loew (Diptera: Phoridae) Infestation of the Invasive Pest Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in China.

Simple SummaryThe invasive pest Spodoptera frugiperda first emerged in China in 2019, and therefore the information on indigenous natural enemies of S. frugiperda has been limited in China. In this study, we reported that a dipteran species was observed to infest S. frugiperda collected from maize fields in four different regions of China. Further morphological and molecular recognition identified all the flies as Megaselia scalaris. The findings of this study will improve our understanding on natural enemies to S. frugiperda and potentially provide new ideas for integrated pest management strategies in China.The invasive pest Spodoptera frugiperda first emerged in China in January 2019 and has, to date, migrated to 29 provinces and municipalities in China, causing heavy crop damage in large areas. As a response to this invasive species from the environment, some indigenous natural enemies have been discovered and reported after S. frugiperda invasion. In this paper, parasitic flies were collected and identified from S. frugiperda collected in the Yunnan, Guangxi, and Henan provinces and the Chongqing municipality in China. By using both conventional and molecular approaches, we were able to show that all the parasitic flies of S. frugiperda identified in the four regions were Megaselia. scalaris, and that they attacked the pest larvae and pupae. This is the first report on an indigenous Chinese Megaselia species that has parasitic ability against the invasive pest S. frugiperda, potentially providing new ideas for pest control in China.

Toxoplasma gondii and Psychopathology: Latent Infection Is Associated with Interpersonal Sensitivity, Psychoticism, and Higher Testosterone Levels in Men, but Not in Women

ObjectiveThe ability of parasites to hijack the nervous system, manipulating the host’s physiology and behavior in ways that enhance the parasite’s fitness while damaging host fitness, is a topic of ongoing research interest in evolutionary biology, but is largely overlooked in mental health research. Nevertheless, recent evidence has shown that Toxoplasma gondii infection can change host testosterone levels and influence the development of some psychiatric disorders. Here, we tested this hypothesis in a mixed sample of 213 non-clinical subjects.MethodsParticipants (nmales = 108, nfemales = 105) provided 5 ml of blood to quantify testosterone levels and Toxoplasma gondii antibodies. The Symptom Checklist-90-Revised was used to assess psychopathological symptoms.ResultsThe results showed that Toxoplasma-infected men had higher testosterone levels and scored higher in Interpersonal Sensitivity and Psychoticism symptoms than non-infected men. Toxoplasma-infected women did not differ from control women.ConclusionsFramed in an evolutionary framework, the findings suggest that the elevated testosterone levels and the expression of psychopathological symptoms can be seen as the result of the manipulation exerted by Toxoplasma gondii either to reach its definitive host or to increase its spread. Future research can benefit from integrating insights from evolutionary biology and parasite-host interactions with physiology, immunology, and mental health to develop a better understanding of mental health etiology.

Introductory Chapter: The Importance of Heat Shock Proteins in Survival and Pathogenesis of the Malaria Parasite Plasmodium falciparum.

Malaria did not die with the end of the age of western colonization but is still a major public health issue in large parts of the world. Despite repeated and concerted efforts to eradicate this disease, it has proved remarkably resilient, and constant vigilance and continuous research are required to discover new chinks in the parasite's armor and alleviate the suffering at both the individual and societal levels. A deeper understanding of the fundamental processes underlying parasite survival, propagation, virulence, and ability to cause disease is the key to the development of desperately needed new therapies and prophylactic drugs. Malaria parasites, by the nature of their lifecycle, are subject to a number of environmental and cellular stresses which they must overcome to survive. To this end, they express a number of heat shock proteins (HSPs), molecules specialized on buffering the effects of external stimuli, but which are also essential for normal cellular biochemistry. In this introductory chapter, I give a brief overview of the diversity of structure, function, and importance of these HSPs, and highlight some of the current and future research questions in this field. Additionally, this chapter acts as a bridge to the other chapters in this book. These chapters, I think you will agree, demonstrate that with regard to HSPs malaria parasites, as in so many things, obey the adage "Same same, but different."

Cold water reduces the severity of parasite-inflicted damage: support for wintertime recuperation in aquatic hosts.

The reduction in host fitness caused by parasite infections (virulence) depends on infection intensity and the degree of damage caused per parasite. Environmental conditions can shape both virulence components, but in contrast to infection intensity, environmental impacts on per-parasite damage are poorly understood. Here, we studied the effect of ambient temperature on per-parasite damage, which is jointly determined by the ability of parasites to induce harm (per-parasite pathogenicity) and the ability of hosts to limit damage (tolerance). We experimentally exposed two salmonid species, Atlantic salmon (Salmo salar) and sea trout (Salmo trutta), to replicated genotypes of the eye fluke Diplostomum pseudospathaceum. After development of health damage (eye cataracts) in warm water (16°C) during the first 12weeks post exposure, we maintained the fish at either 5°C (cold water) or 16°C for another 8weeks and quantified changes in cataracts as a function of parasite load. We found that per-parasite damage was reduced in cold compared to warm water, suggesting that cold temperatures improved host health. Per-parasite damage was also affected by parasite genotype and host species, but these effects did not change with temperature. Our findings suggest that cold-water seasons, which are often neglected in host-parasite studies due to low infection risk, could allow hosts to recuperate and thus, may have important implications for the ecology and epidemiology of parasite infections.

Analysis of the Distributed Immune Inspection Equipment Sensor Scheduling Model Based on Adaptive Dynamic Probabilistic Particle Swarm Optimization

Based on the analysis of bacterial parasitic behavior and biological immune mechanism, this paper puts forward the basic idea and implementation method of an embedding adaptive dynamic probabilistic parasitic immune mechanism into a particle swarm optimization algorithm and constructs particle swarm optimization based on an adaptive dynamic probabilistic parasitic immune mechanism algorithm. The specific idea is to use the elite learning mechanism for the parasitic group with a strong parasitic ability to improve the ability of the algorithm to jump out of the local extreme value, and the host will generate acquired immunity against the parasitic behavior of the parasitic group to enhance the diversity of the host population’s particles. Parasitic behavior occurs when the number of times reaches a predetermined algebra. In this paper, an example simulation is carried out for the prescheduling and dynamic scheduling of immune inspection. The effectiveness of prescheduling for immune inspection is verified, and the rules constructed by the adaptive dynamic probability particle swarm algorithm and seven commonly used scheduling rules are tested on two common dynamic events of emergency task insertion and subdistributed immune inspection equipment failure. In contrast, the experimental data was analyzed. From the analysis of experimental results, under the indicator of minimum completion time, the overall performance of the adaptive dynamic probability particle swarm optimization algorithm in 20 emergency task insertion instances and 20 subdistributed immune inspection equipment failure instances is better than that of seven scheduling rules. Therefore, in the two dynamic events of emergency task insertion and subdistributed immune inspection equipment failure, the adaptive dynamic probabilistic particle swarm algorithm proposed in this paper can construct effective scheduling rules for the rescheduling of the system when dynamic events occur and the constructed scheduling. The performance of the rules is better than that of the commonly used scheduling rules. Among the commonly used scheduling rules, the performance of the FIFO scheduling rules is also better. In general, the immune inspection scheduling multiagent system in this paper can complete the prescheduling of immune inspection and process dynamic events of the inspection process and realize the prereactive scheduling of the immune inspection process.

Binding of human serum proteins to Plasmodium falciparum-infected erythrocytes and its association with malaria clinical presentation

BackgroundThe pathogenesis of Plasmodium falciparum malaria is related to the ability of parasite‑infected erythrocytes (IEs) to adhere to the vascular endothelium (cytoadhesion/sequestration) or to surrounding uninfected erythrocytes (rosetting). Both processes are mediated by the expression of members of the clonally variant PfEMP1 parasite protein family on the surface of the IEs. Recent evidence obtained with laboratory-adapted clones indicates that P. falciparum can exploit human serum factors, such as IgM and α2-macroglobulin (α2M), to increase the avidity of PfEMP1-mediated binding to erythrocyte receptors, as well as to evade host PfEMP1-specific immune responses. It has remained unclear whether PfEMP1 variants present in field isolates share these characteristics, and whether they are associated with clinical malaria severity. These issues were investigated here.MethodsChildren 1–12 years reporting with P. falciparum malaria to Hohoe Municipal Hospital, Ghana were enrolled in the study. Parasites from children with uncomplicated (UM) and severe malaria (SM) were collected. Binding of α2M and IgM from non-immune individuals to erythrocytes infected by P. falciparum isolates from 34 children (UM and SM) were analysed by flow cytometry. Rosetting in the presence of IgM or α2M was also evaluated. Experimental results were analysed according to the clinical presentation of the patients.ResultsClinical data from 108 children classified as UM (n = 54) and SM cases (n = 54) were analysed. Prostration, severe malaria anaemia, and hyperparasitaemia were the most frequent complications. Three children were diagnosed with cerebral malaria, and one child died. Parasite isolates from UM (n = 14) and SM (n = 20) children were analysed. Most of the field isolates bound non-immune IgM (33/34), whereas the α2M-binding was less common (23/34). Binding of both non-immune IgM and α2M was higher but not significant in IEs from children with SM than from children with UM. In combination, IgM and α2M supported rosette formation at levels similar to that observed in the presence of 10% human serum.ConclusionsThe results support the hypothesis that binding of non-immune IgM and/or α2M to IEs facilitates rosette formation and perhaps contributes to P. falciparum malaria severity.

Adaptive Radiation of Four-Legged Mites of the Family Phytoptidae (Acariformes, Eriophyoidea) on Dicotyledons: Host–Parasite Relationships and Ability to Induce Gallogenesis

Four-legged mites of the family Phytoptidae (Acariformes, Eriophyoidea) are represented on eudicot plants by 31 species of two subfamilies: Phytoptinae (1 genus, 19 species) and Sierraphytoptinae (7 genera, 12 species). Most phytoptid species that are capable of inducing various growth abnormalities in plants (galls, erinea, bud growth, and other injuries) belong to the subfamily Phytoptinae. Analysis of the quantitative traits has shown that no groups of phytoptid species associated with eudicots can be outlined based on the currently available morphometric characters. The correlation between the prodorsal shield ornamentation, the presence of the tibial solenidion, and the geographic distribution of phytoptid mites is analyzed, and groups of phytoptine species with similar prodorsum topography are discussed. Analysis of host associations of phytoptids from eudicots has revealed no cophylogenetic patterns; many hosts of phytoptids are narrow-range endemics and relicts. It is supposed that phytoptids originated in the tropics or in the Southern Hemisphere. The current classification of phytoptids into subfamilies is probably artificial; it does not reflect the phylogeny of this group and needs a revision based on molecular phylogenetic data.