Parasite Invasion Research Articles

Architecture of the Toxoplasma gondii apical polar ring and its role in gliding motility and invasion

In Toxoplasma gondii, the conoid comprises a cone with spiraling tubulin fibers, preconoidal rings, and intraconoidal microtubules. This dynamic organelle undergoes extension and retraction through the apical polar ring (APR) during egress, gliding, and invasion. The forces involved in conoid extrusion are beginning to be understood, and its role in directing F-actin flux to the pellicular space, thereby controlling parasite motility, has been proposed. However, the contribution of the APR and its interactions with the conoid remain unclear. To gain insight into the APR architecture, ultrastructure expansion microscopy was applied to pinpoint known and newly identified APR proteins (APR2 to APR7). Our results revealed that the APR is constructed as a fixed multilayered structure. Notably, conditional depletion of APR2 resulted in significant impairments in motility and invasion. Electron microscopy and cryoelectron tomography revealed that depletion of APR2 alters APR integrity, affecting conoid extrusion and causing cytosolic leakage of F-actin. These findings implicate the APR structure in directing the apico-basal flux of F-actin to regulate parasite motility and invasion.

Advance in Nrf2 Signaling Pathway in Leishmaniasis

One of the main components of innate defense against invasive parasites is oxidative stress, which is brought on by reactive oxygen species (ROS). On the other hand, oxidative stressors serve two purposes: free radicals aid in the elimination of pathogens, but they can also set off inflammation, which leads to tissue damage. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that controls the expression of numerous genes involved in the body’s defense against oxidative stress brought on by aging, inflammation, tissue damage, and other pathological consequences. From cutaneous to visceral forms, Leishmania parasites invade macrophages and cause a wide range of human pathologies. Leishmania parasites have a wide range of adaptive mechanisms that disrupt several macrophage functions by altering host signaling pathways. An increasing amount of data are corroborating the idea that one of the primary antioxidant routes to counteract this oxidative burst against parasites is NRF2 signaling, which also interferes with immune responses. The nature and potency of the host immune response, as well as interactions between the invading Leishmania spp., will ascertain the course of infection and the parasites’ eventual survival or eradication. The molecular processes via which Nrf2 coordinates such intricate networks comprising various pathways remain to be completely understood. In light of NRF2’s significant contribution to oxidative stress, we examine the NRF2 antioxidant pathway’s activation mechanism in Leishmania infection in this review. Thus, this review will examine the relationship between Nrf2 signaling and leishmaniasis, as well as explore potential therapeutic strategies for modifying this system.

Potential Role of the Eastern Mosquitofish (Gambusia holbrooki) in the Spread of the Harmful Fish Parasite, Asian Tapeworm Schyzocotyle (Bothriocephalus) acheilognathi

Biological control of undesirable organisms and pathogens often involves the introduction of alien species into new regions. However, alien species themselves pose a potential threat to local ecosystems and economies. The Eastern mosquitofish Gambusia holbrooki is recognised as a dangerous invasive species, but despite this, it is still used for biological control of mosquito larvae, a potential vector of malaria plasmodium transmission to humans, on the Black Sea coast of the Caucasus. We focused on the species composition of helminths in this fish species. We detected adult nematodes Pseudocapillaria (Pseudocapillaria) tomentosa and cestodes Schyzocotyle acheilognathi (formely Bothriocephalus acheilognathi). The above nematode was observed for the first time in fish of the genus Gambusia. Importantly, the cestode S. acheilognathi, which we found in G. holbrooki, is the most successful invasive alien parasite species in freshwaters of the planet and is extremely hazardous to natural ecosystems and aquaculture as it can cause mass mortality of young fish. Thus, the current practice of transferring mosquitofish between water bodies on the Black Sea coast of the Caucasus to control mosquito larvae may contribute to the undesirable spread of a harmful quarantine fish parasite.

Designing a multi-epitope subunit vaccine against Toxoplasma gondii through reverse vaccinology approach

The parasite Toxoplasma gondii, or T. gondii, is zoonotic that both individuals as well as animals can contract resulting in toxoplasmosis, a life-threatening illness. We used an immunoinformatic technique in our research to construct a vaccine with multi-epitopes so that it can decrease the devastating impact caused by this dangerous parasite. In order to construct the vaccine, GRA6 and MIC3 proteins were targeted, which are engaged in T. gondii identification, infection, and immune response. Novel epitopes for linear B lymphocytes (LBL), cytotoxic T lymphocytes (CTL), and helper T lymphocytes (HTL) were found by epitope mapping, every anticipated epitope was assessed through rigorous screening to determine the top choices for epitopes which were entirely preserved, very antigenic in nature, nonallergenic, and nontoxic. 4 CTLs, 3 HTLs and 4 LBL epitopes were chosen and combined along with proper linkers and adjuvants to design a vaccine with several epitopes. Linkers as well as adjuvants were provided to make the vaccine more immunogenic, antigenic, and stable. The proposed vaccination was identified to possess the necessary biophysical properties, be soluble, extremely antigenic, and non-allergic. Reliability of the vaccine design was demonstrated by secondary along with tertiary structure prediction. It was anticipated that the vaccine's three-dimensional structure would likely link up with TLR-2 and TLR-4 via the investigation of molecular docking. TLR-2 and TLR-4 are crucial for the parasite's invasion and the body's response. In our docking investigation, both TLRs demonstrated strong binding affinities utilizing the vaccine structure. After that, the vaccine construct's elevated expression rate, which was observed in Escherichia coli strain K12, was confirmed by an investigation using in silico cloning and codon adaptation. The results of the research are really encouraging and some properties of the vaccine were found to be significantly better than existing the T. gondii multi-epitope vaccination based on the same proteins. Nonetheless, in vivo trials are strongly suggested for potential future studies.

An endoplasmic reticulum localized acetyl-CoA transporter is required for efficient fatty acid synthesis in Toxoplasma gondii.

Toxoplasma gondii is an obligate intracellular parasite that can infect humans and diverse animals. Fatty acids are critical for the growth and proliferation of T. gondii, which has at least two pathways to synthesize fatty acids, including the type II de novo synthesis pathway in the apicoplast and the elongation pathway in the endoplasmic reticulum (ER). Acetyl-CoA is the key substrate for both fatty acid synthesis pathways. In the apicoplast, acetyl-CoA is mainly provided by the pyruvate dehydrogenase complex. However, how the ER acquires acetyl-CoA is not fully understood. Here, we identified a putative acetyl-CoA transporter (TgAT1) that localized to the ER of T. gondii. Deletion of TgAT1 impaired parasite growth and invasion in vitro and attenuated tachyzoite virulence in vivo. Metabolic tracing using 13C-acetate found that loss of TgAT1 reduced the incorporation of 13C into certain fatty acids, suggesting reduced activities of elongation. Truncation of AT1 was previously reported to confer resistance to the antimalarial compound GNF179 in Plasmodium falciparum. Interestingly, GNF179 had much weaker inhibitory effect on Toxoplasma than on Plasmodium. In addition, deletion of AT1 did not affect the susceptibility of Toxoplasma to GNF179, suggesting that this compound might be taken up differently or has different inhibitory mechanisms in these parasites. Together, our data show that TgAT1 has important roles for parasite growth and fatty acid synthesis, but its disruption does not confer GNF179 resistance in T. gondii.

The Description of Microbial Pattern and Antibiotic Sensitivity Among Pediatric Patients at RSUP M Djamil Padang

Background Infection alludes to the invasion and multiplication of either microorganisms or parasites inside bodily tissues. The management of such infections is closely interrelated to the use of antibiotics. Ineffective use of antibiotics is contributed to the antibiotic resistance. Severe disease complications and lengthy hospital stays are among essential reasons why physicians may prescribe myriad types of antibiotics for longer durations. In effort to diminish resistance, the selection of antibiotics ought to be based on information about the bacterial spectrum causing the infection and the patterns of sensitivity to antibiotics. Annual reporting of microbial patterns and sensitivity testing is essential, particularly for pediatric ward patients, as it provides a guide for administering relevant antibiotics and preventing further spread of infections. Objectives This study evaluated microbial patterns, sensitivity test results, and antibiotic resistance among patients in the pediatric ward of RSUP M Djamil Padang from January-December 2020, with a total of 138 samples. Results The proportion of gram-negative and gram-positive bacteria are 83.3% and 16.7%, respectively. The most prevalent gram-negative bacteria are Klebsiella pneumoniae (28.9%), Escherichia coli (26.1%). Pseudomonas aeruginosa (7.9%), Staphylococcus epidermidis (7.2%) and Acinetobacter baumannii (3.7%) also present. These bacteria are predominantly found in samples of feces, urine, and blood. Gram-positive bacteria show notable resistance to the antibiotics such as erythromycin (22.2%), trimethoprim-sulfamethoxazole (19%), and ciprofloxacin (15.8%), while being sensitive to chloramphenicol (17.4%), vancomycin (15.1%), and tetracycline (12%). In contrast, gram-negative bacteria exhibit resistance to ampicillin (16.5%), ceftriaxone (12.1%), and ceftazidime (11.3%), but are sensitive to amikacin (19.8%), meropenem (19.4%), and gentamicin (10.9%). Keywords: microbial patterns, antibiotic sensitivity, pediatric ward

An in vitro platform for the enzymatic characterization of the rhomboid protease RHBDL4.

Rhomboid proteases are ubiquitous intramembrane serine proteases that can cleave transmembrane substrates within lipid bilayers. They exhibit many and diverse functions, such as but not limited to, growth factor signaling, immune and inflammatory response, protein quality control, and parasitic invasion. Human rhomboid protease RHBDL4 has been demonstrated to play a critical role in removing misfolded proteins from the Endoplasmic Reticulum and is implicated in severe diseases such as various cancers and Alzheimer's disease. Therefore, RHBDL4 is expected to constitute an important therapeutic target for such devastating diseases. Despite its critical role in many biological processes, the enzymatic properties of RHBDL4 remain largely unknown. To enable a comprehensive characterization of RHBDL4's kinetics, catalytic parameters, substrate specificity, and binding modality we expressed and purified recombinant RHBDL4, and employed it in a Förster Resonance Energy Transfer-based cleavage assay. Until now, kinetic studies have been limited mostly to bacterial rhomboid proteases. Our in vitro platform offers a new method for studying RHBDL4's enzymatic function and substrate preferences. Furthermore, we developed and tested potential inhibitors using our assay and successfully identifying peptidyl α-ketoamide inhibitors of RHBDL4 that are highly effective against recombinant RHBDL4. We utilize ensemble docking and molecular dynamics (MD) simulations to explore the binding modality of substrate-derived peptides bound to RHBDL4. Our analysis focused on key interactions and dynamic movements within RHBDL4's active site that contributed to binding stability, offering valuable insights for optimizing the non-prime side of RHBDL4 ketoamide inhibitors. In summary, our study offers fundamental insights into RHBDL4's catalytic activities and substrate preferences, laying the foundation for downstream applications such as drug inhibitor screenings and structure-function studies, which will enable the identification of lead drug compounds for RHBDL4.

Onametostat, a PfPRMT5 inhibitor, exhibits antimalarial activity to Plasmodium falciparum.

Protein arginine methyltransferases (PRMTs) play critical roles in Plasmodium falciparum, a protozoan causing the deadliest form of malaria, making them potential targets for novel antimalarial drugs. Here, we screened 11 novel PRMT inhibitors against P. falciparum asexual growth and found that onametostat, an inhibitor for type II PRMTs, exhibited strong antimalarial activity with a half-maximal inhibitory concentration (IC50) value of 1.69 ± 0.04 µM. In vitro methyltransferase activities of purified PfPRMT5 were inhibited by onametostat, and a shift of IC50 to onametostat was found in the PfPRTM5 disruptant parasite line, indicating that PfPRTM5 is the primary target of onametostat. Consistent with the function of PfPRMT5 in mediating symmetric dimethylation of histone H3R2 (H3R2me2s) and in regulating invasion-related genes, onametostat treatment led to the reduction of H3R2me2s level in P. falciparum and caused the defects on the parasite's invasion of red blood cells. This study provides a starting point for identifying specific PRMT inhibitors with the potential to serve as novel antimalarial drugs.

Historical invasion rates vary among insect trophic groups.

Globalization has spread thousands of invasive insect species into new world regions,1,2,3 causing severe losses in ecosystem services. Previous work proposed that plant invasions facilitate insect invasions through the creation of niches for non-native herbivores.3,4,5,6 Despite the impact of insect invasions, a comprehensive understanding is lacking on how invasion success varies among insect feeding groups. We therefore compiled the predominant larval trophic groups (herbivores, predators, parasites, detritivores, and brood-carers) for 5,839 non-native insect species in nine world regions to compare (1) proportions of species in each group between non-native species and the world's fauna, (2) how invasion success for each trophic group has changed over the last three centuries, and (3) how historical herbivore invasions are related to plant invasions over time and parasite invasions are related to herbivores. We find that herbivores represent a significantly larger proportion (52.4%) among non-native insects compared with the world fauna (38.4%), whereas proportions of non-native detritivores (including fungivores), predators, and brood-carers are significantly lower; parasite proportions do not significantly differ. Predators and detritivores dominated among invasions in the 18th century but subsequently diminished, likely due to changing invasion pathways, whereas proportions of herbivores, parasites, and brood-carers increased over time. We found herbivore invasions to lag 80 years behind plant invasions, whereas parasitoids appear to co-invade with their herbivore hosts. The dominance of herbivores among non-native insects and their strong cross-correlation with plant invasions further strengthens the hypothesis that plant invasions drive the global rise in numbers of non-native insects.

Whole-Transcriptome Analysis Reveals Potential CeRNA Regulatory Mechanism in Takifugu rubripes against Cryptocaryon irritans Infection.

Cryptocaryon irritans (C. irritans) is a proto-ciliate parasite that infects marine fishes, including the cultured species Takifugu rubripes (T. rubripes), causing disease and potential mortality. In host organisms, infection by parasites triggers an immune response that is modulated by regulatory elements including proteins and non-coding RNAs. In this study, the whole transcriptome RNA sequencing of T. rubripes gill tissue before and after infection with C. irritans was performed to reveal the competitive endogenous RNA (ceRNA) regulatory network. Histomorphology revealed gill segment swelling and parasitic invasion in the infected group. The analysis identified 18 differentially expressed miRNAs (DEMs), 214 lncRNAs (DELs), 2501 genes (DEGs), and 7 circRNAs (DECs) in the infected group. Gene Ontology (GO) enrichment analysis revealed that these genes were notably enriched in the Wnt signaling pathway and mTOR signaling pathway. The co-expression networks (lncRNA/circRNA-miRNA-mRNA) were constructed based on correlation analysis of the differentially expressed RNAs. Further analysis suggested that the LOC105418663-circ_0000361-fru-miR-204a-fzd3a ceRNA axis was potentially involved in the regulation of immune responses against C. irritans infection. Finally, the expression levels of DEG, DEL, and DEM were validated. This study reveals the regulatory mechanism of a candidate ceRNA network, providing insights into the potential mechanism of T. rubripes' infection with C. irritans.

In silico analysis and structural vaccinology prediction of Toxoplasma gondii ROP41 gene via immunoinformatics methods as a vaccine candidate

IntroductionToxoplasma gondii (T. gondii) infects all warm-blooded animals, including humans. Currently, no effective treatments exist to prevent the generation of chronic tissue cysts in infected hosts. Therefore, developing a vaccine to protect to deal with toxoplasmosis is a promising strategy, as a single immunization could provide lifelong protective immunity. Rhoptry proteins (ROPs) play a vital role for the parasite's survival within host cells and perform critical functions during different phases of parasite invasion. Little is known about ROP41 gene. Nevertheless, Understanding the characteristics of ROP41 will enhance diagnostic and vaccine research. Materials and MethodsThe current article provides a comprehensive analysis of the essential components of the ROP41 protein, including its transmembrane domain, physico-chemical properties, subcellular location, tertiary and secondary structures, and potential T- and B-cell epitopes. These features were determined by many bioinformatics approaches to identify possible epitopes for developing a highly effective vaccine. ResultsROP41 protein showed 36 possible post-translational modification regions. The ROP41 protein secondary structure contains 17.35 % extended strand, 33.47 % alpha-helix, and 49.18 % random coil. Also, ROP41 showed many possible B- and T-cell epitopes. According to the Ramachandran plot, 90.78 % of amino acid residues had been placed in favored, 3.28 % in outlier, and 5.94 % in allowed areas. Also, the allergenicity and antigenicity evaluation indicated that ROP41 is non-allergenic and immunogenic. ConclusionThe current study offered critical basic and conceptual information on ROP41 to increase a successful vaccine in opposition to continual and acute toxoplasmosis for in addition in vivo assessments. Further research is necessary for the development of vaccines utilizing ROP41 alone or combined with various antigens.

KORELASI PERILAKU HIDUP BERSIH DAN SEHAT DENGAN KECACINGAN PADA SISWA SEKOLAH DASAR DI KABUPATEN PROBOLINGGO

Background: Soil-transmitted worms are still a health problem in Probolinggo Regency, especially related to clean and healthy living behavior. Health and hygiene education is an effort to reduce worm transmission and infection. The purpose of this study was to identify clean and healthy living behaviors related to worms. Method: The study design was observational analytic with a Cross-Sectional Study approach. The population was elementary school students in Probolinggo Regency with a sample size of 607 students taken by cluster sampling with a single-stage method. Identification was carried out on clean and healthy living behaviors and the number of worm eggs in feces and soil. Data analysis used Chi Square with an alpha of 0.05. Results: The data showed that 96.4% of respondents were negative and 3.6% were positive with a distribution of worm eggs of 2.1% Ascaris lumbricoides, 1.3% Hookworm and 0.5% Trichuris trichiura with mild infection intensity. The results of the Chi Square test showed no relationship between washing hands before eating, washing hands after defecating, wearing footwear, and nail conditions with worms in students with p values of 0.748, 0.584, 0.550, 0.777, respectively. Conclusion: These results are due to the history of exposure and the body's immunity in overcoming parasite invasion. Long exposure to children with positive worms will make the parasite colony maintain a clean and healthy lifestyle. Conversely, low exposure and strong immunity keep children free from worm infections.

Effective Laboratory Diagnosis of Parasitic Infections of the Gastrointestinal Tract: Where, When, How, and What Should We Look For?

(1) Introduction: Gastrointestinal parasites (GIPs) are one of the most common causes of disease in the world. Clinical diagnosis of most parasitic diseases is difficult because they do not produce characteristic symptoms. (2) Methods: The PubMed, Science Direct, and Wiley Online Library medical databases were reviewed using the following phrases: "parasitic infections and diagnostics", "intestinal parasites", "gastrointestinal parasites", "parasitic infections and diagnostics", and their combinations. (3) Results and Conclusions: Correct diagnosis of GIP involves determining the presence of a parasite and establishing a relationship between parasite invasion and disease symptoms. The diagnostic process should consider the possibility of the coexistence of infection with several parasites at the same time. In such a situation, diagnostics should be planned with consideration of their frequency in each population and the local epidemiological situation. The importance of the proper interpretation of laboratory test results, based on good knowledge of the biology of the parasite, should be emphasized. The presence of the parasite may not be causally related to the disease symptoms. Due to wide access to laboratories, patients often decide to perform tests themselves without clinical justification. Research is carried out using various methods which are often unreliable. This review briefly covers current laboratory methods for diagnosing the most common gastrointestinal parasitic diseases in Europe. In particular, we provide useful information on the following aspects: (i) what to look for and where to look for it (suitability of feces, blood, duodenal contents, material taken from endoscopy or biopsy, tissue samples, and locations for searching for eggs, cysts, parasites, parasite genetic material, and characteristics of immune responses indicating parasitic infections); (ii) when material should be collected for diagnosis and/or to check the effectiveness of treatment; (iii) how-that is, by what methods-laboratory diagnostics should be carried out. Here, the advantages and disadvantages of direct and indirect methods of detecting parasites will be discussed. False-positive or false-negative results are a problem facing many tests. Available tests have different sensitivities and specificities. Therefore, especially in doubtful situations, tests for the presence of the pathogen should be performed using various available methods. It is important that the methods used make it possible to distinguish an active infection from a past infection. Finally, we present laboratory "case reports", in which we will discuss the diagnostic procedure that allows for the successful identification of parasites. Additionally, we briefly present the possibilities of using artificial intelligence to improve the effectiveness of diagnosing parasitic diseases.

Host preference and physiological performance of the invasive hemiparasite of coastal communities <i>Cassytha filiformis</i> L. (Lauraceae)

Background: Invasive parasitic species have barely been studied despite their impact on the communities they invade. Questions: What is the host range used by the invasive parasite Cassytha filiformis in the coastal scrubland of northern Yucatan? Does C. filiformis show host preference? Does the physiological performance of C. fliformis (water deficit and chlorophyll content) vary among hosts on which it establishes and reproduces? Study species: Cassytha filiformis, an invasive hemiparasitic vine of coastal communities. Study sites and dates: Telchac, Yucatán, México. The study lasted from October 2022 to June 2023. Methods: The incidence of C. filiformis parasitism was recorded. Histological analysis confirmed parasitism, and the water potential and chlorophyll concentration of C. filiformis in its main hosts were determined. Results: C. filiformis parasitized 10 species, showing a preference for shrubs. Its main hosts were Scaevola plumieri, Phitecellobium keyense and Croton punctatus. Differences between hosts were observed in water potential variation and total chlorophyll concentration. Differences between stem types (young and mature) in chlorophyll concentration were also observed. Conclusions: C. filiformis prefers shrub species to establish. The physiological performance of C. filiformis varied depending on host identity. Differences in chlorophyll concentration between stem types of C. filiformis suggest functional physiological differences between them.

Leucinostatins from fungal extracts block malaria transmission to mosquitoes

BackgroundMalaria is a mosquito-transmitted disease that kills more than half a million people annually. The lack of effective malaria vaccines and recently increasing malaria cases urge innovative approaches to prevent malaria. Previously, we reported that the extract from the soil-dwelling fungus Purpureocillium lilacinum, a common fungus from the soil, reduced Plasmodium falciparum oocysts in Anopheles gambiae midguts after mosquitoes contacted the treated surface before feeding.MethodsWe used liquid chromatography to fraction fungal crude extract and tract the active fraction using a contact-wise approach and standard membrane feeding assays. The purified small molecules were analyzed using precise mass spectrometry and tandem mass spectrometry.ResultsWe isolated four active small molecules from P. lilacinum and determined them as leucinostatin A, B, A2, and B2. Pre-exposure of mosquitoes via contact with very low-concentration leucinostatin A significantly reduced the number of oocysts. The half-maximal response or inhibition concentration (EC50) via pre-exposure was 0.7 mg/m2, similar to atovaquone but lower than other known antimalarials. The inhibitory effect of leucinostatin A against P. falciparum during intraerythrocytic development, gametogenesis, sporogonic development, and ookinete formation, with the exception of oocyst development, suggests that leucinostatins play a part during parasite invasion of new cells.ConclusionsLeucinostatins, secondary metabolites from P. lilacinum disrupt malaria development, particular transmission to mosquitoes by contact. The contact-wise malaria control as a nonconventional approach is highly needed in malaria-endemic areas.Graphical

HBeeID: a molecular tool that identifies honey bee subspecies from different geographic populations

BackgroundHoney bees are the principal commercial pollinators. Along with other arthropods, they are increasingly under threat from anthropogenic factors such as the incursion of invasive honey bee subspecies, pathogens and parasites. Better tools are needed to identify bee subspecies. Genomic data for economic and ecologically important organisms is increasing, but in its basic form its practical application to address ecological problems is limited.ResultsWe introduce HBeeID a means to identify honey bees. The tool utilizes a knowledge-based network and diagnostic SNPs identified by discriminant analysis of principle components and hierarchical agglomerative clustering. Tests of HBeeID showed that it identifies African, Americas-Africanized, Asian, and European honey bees with a high degree of certainty even when samples lack the full 272 SNPs of HBeeID. Its prediction capacity decreases with highly admixed samples.ConclusionHBeeID is a high-resolution genomic, SNP based tool, that can be used to identify honey bees and screen species that are invasive. Its flexible design allows for future improvements via sample data additions from other localities.

Do Babesia microti Hosts Share a Blood Group System Gene Ortholog, Which Could Generate an Erythrocyte Antigen That Is Essential for Parasite Invasion?

The United States of America (US) has the highest annual number of human babesiosis cases caused by Babesia microti (Bm). Babesia, like malaria-causing Plasmodium, are protozoan parasites that live within red blood cells (RBCs). Both infectious diseases can be associated with hemolysis and organ damage, which can be fatal. Since babesiosis was made a nationally notifiable condition by the Centers for Disease Control and Prevention (CDC) in January 2011, human cases have increased, and drug-resistant strains have been identified. Both the Bm ligand(s) and RBC receptor(s) needed for invasion are unknown, partly because of the difficulty of developing a continuous in vitro culture system. Invasion pathways are relevant for therapies (e.g., RBC exchange) and vaccines. We hypothesize that there is at least one RBC surface antigen that is essential for Bm invasion and that all Bm hosts express this. Because most RBC surface antigens that impact Plasmodium invasion are in human blood group (hBG) systems, which are generated by 51 genes, they were the focus of this study. More than 600 animals with at least one hBG system gene ortholog were identified using the National Center for Biotechnology Information (NCBI) command-line tools. Google Scholar searches were performed to determine which of these animals are susceptible to Bm infection. The literature review revealed 28 Bm non-human hosts (NHH). For 5/51 (9.8%) hBG system genes (e.g., RhD), no NHH had orthologs. This means that RhD is unlikely to be an essential receptor for invasion. For 24/51 (47.1%) hBG system genes, NHH had 4-27 orthologs. For the ABO gene, 15/28 NHH had an ortholog, meaning that this gene is also unlikely to generate an RBC antigen, which is essential for Bm invasion. Our prior research showed that persons with blood type A, B, AB, O, RhD+, and RhD- can all be infected with Bm, supporting our current study's predictions. For 22/51 (43.1%) hBG system genes, orthologs were found in all 28 NHH. Nineteen (37.3%) of these genes encode RBC surface proteins, meaning they are good candidates for generating a receptor needed for Bm invasion. In vitro cultures of Bm, experimental Bm infection of transgenic mice (e.g., a CD44 KO strain), and analyses of Bm patients can reveal further clues as to which RBC antigens may be essential for invasion.

Three odorant-binding proteins of small hive beetles, Aethina tumida, participate in the response of bee colony volatiles

Aethina tumida (small hive beetle, SHB) is a rapidly spreading invasive parasite of bee colonies. The olfactory system plays a key role in insect behavior, and odorant-binding proteins (OBPs) are involved in the first step of the olfactory signal transduction pathway and the detection of host volatiles. However, the olfactory mechanism of OBPs in SHB-localized bee colonies is unclear. In this study, electroantennogram (EAG) and behavioral bioassay showed that only three compounds (2-heptanone, ocimene, and ethyl palmitate) from bee colonies triggered high electrophysiological and behavioral responses. Three antenna-specific OBP genes (OBP6, OBP11, and OBP19) were identified, and they were significantly expressed on adult days 6–7. Furthermore, by combining RNA interference (RNAi) with EAG, olfactometer bioassay, competitive fluorescence binding assays, and molecular docking, we found that these three OBP genes were involved in the recognition of 2-heptanone and ethyl palmitate, and AtumOBP6 is also involved in the recognition of ocimene. These data indicate that AtumOBP6, AtumOBP11, and AtumOBP19 play an important role in the olfactory response to bee colony volatiles. Our results provide new insights into the functions of the OBP families in A. tumida and help to explore more potential target genes for environmentally friendly pest control strategies.

Analysis of the diverse antigenic landscape of the malaria protein RH5 identifies a potent vaccine-induced human public antibody clonotype

The highly conserved and essential Plasmodium falciparum reticulocyte-binding protein homolog 5 (PfRH5) has emerged as the leading target for vaccines against the disease-causing blood stage of malaria. However, the features of the human vaccine-induced antibody response that confer highly potent inhibition of malaria parasite invasion into red blood cells are not well defined. Here, we characterize 236 human IgG monoclonal antibodies, derived from 15 donors, induced by the most advanced PfRH5 vaccine. We define the antigenic landscape of this molecule and establish that epitope specificity, antibody association rate, and intra-PfRH5 antibody interactions are key determinants of functional anti-parasitic potency. In addition, we identify a germline IgG gene combination that results in an exceptionally potent class of antibody and demonstrate its prophylactic potential to protect against P.falciparum parasite challenge invivo. This comprehensive dataset provides a framework to guide rational design of next-generation vaccines and prophylactic antibodies to protect against blood-stage malaria.

On the fauna of parasites of the gastrointestinal tract of small ruminants in the mountainous zone of Armenia

The aim of the research is to study the parasitic invasion of small ruminants in the mountainous zone of Armenia during summer and autumn, in this case to determine the invasiveness of parasites of the digestive tract of sheep.The material was feces collected from sheep on pastures in the coastal zone of the Getik River during 2022. The work was carried out at the Scientific Centre of Zoology and Hydroecology, National Academy of Sciences, Republic of Armenia. The material researched also included mollusks and oribatid mites – intermediate hosts of biohelminths.As a result of the study of parasitic invasion of small ruminants in the mountain zone of Armenia, the taxonomic composition of parasites was determined. Helminths found in sheep belong to the classes Trematoda, Nematoda, and Cestoda, protozoa – to the class Protozoa.In the autumn season, representatives of seven genera of parasites of the gastrointestinal tract were found – Moniezia, Dicrocoelium, Fasciola, Nematodirus, Strongylus, Trichuris, Eimeria, while in the summer season, only representatives of five genera were found – Moniezia, Dicrocoelium, Nematodirus, Strongylus, Eimeria.As a result of these studies, it can be concluded that natural and climatic factors of the environment have a significant impact on the structure of the helminth complex of sheep in the mountain region of Armenia.All parasites found can have a detrimental effect on the sheep's body. However, the severity of the invasion in the samples taken is not at the level that could lead to serious diseases in sheep. This suggests that the treatment methods used on farms are at a fairly high level.