The role of small heat shock proteins in parasites

The role of heat shock protein B8 in neuronal protection against oxidative stress and mitochondrial dysfunction: A literature review

Excessive oxidative stress triggers cerebrovascular and neurodegenerative diseases resulting in acute and chronic brain injury. However, the underlying mechanisms remain unknown. Levels of small heat shock protein B8 (HSPB8), which is highly expressed in the brain, are known to be significantly elevated in cerebral injury models. Exogenous HSPB8 protects the brain against mitochondrial damage. One potential mechanism underlying this protection is that HSPB8 overexpression alleviates the mitochondria-dependent pathways of apoptosis; mitochondrial biogenesis, fission, and mitophagy. Overexpression of HSPB8 may therefore have potential as a clinical therapy for cerebrovascular and neurodegenerative diseases. This review provides an overview of advances in the protective effects of HSPB8 against excessive cerebral oxidative stress, including the modulation of mitochondrial dysfunction and potent signaling pathways.

Proteomic analysis of extracellular vesicles and extracellular vesicle-depleted excretory-secretory products of Toxocara canis and Toxocara cati larval cultures

Toxocara canis and Toxocara cati are parasitic nematodes in the order Ascaridida, which inhabit the small intestines of dogs and cats, respectively, as adults. Although often nonpathogenic as adults, nematodes within this genus are capable of causing widespread disease throughout the host while in a larval stage, during which time larvae migrate throughout the body in a process termed larva migrans. Larvae are also capable of surviving within host tissues in an encysted arrested stage, without immune clearance by the host. The ability of larvae to survive within host tissues during migration and encystment may be attributed to immunomodulatory molecules released by the excretory cells of larvae in excretory-secretory (ES) products. ES products of parasites contain a variety of molecules, including proteins, lipids, and extracellular vesicles (EVs). Toxocara excretory-secretory (TES) products have been studied to some degree, with proteomic analysis of TES proteins described previously; however, investigation of the EVs within TES is lacking, despite the suggested role for these molecules in host interaction and potential immunomodulation. To further characterize the protein cargo within EVs in TES, EVs were isolated from larval cultures of T. canis and T. cati via ultrafiltration, with concurrent collection of EV-depleted TES filtrate for additional study. Isolated EVs and EV-depleted TES from both T. canis and T. cati were submitted for proteomic analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS). Proteomic identification results revealed 140 proteins across all samples, with 16 shared by all samples, and 76 total proteins shared between T. canis and T. cati, present within EVs and EV-depleted TES. There were 17 proteins shared exclusively by EV samples, and 15 were shared exclusively between EV-depleted TES samples. Many shared proteins were associated with the host immune response. Several proteins were specific to either T. canis or T. cati, highlighting the potential use of these proteins as diagnostic tools in the differentiation of etiologic agents in cases of toxocariasis. The results of this study build upon previously reported proteomic evaluations of TES, contributing new information in regards to newly identified proteins, EV protein cargo within TES, and potential immunomodulatory functions of these proteins.

The identification of small molecule inhibitors with anthelmintic activities that target conserved proteins among ruminant gastrointestinal nematodes

Gastrointestinal nematode (GIN) infections are a major concern for the ruminant industry worldwide and result in significant production losses. Naturally occurring polyparasitism and increasing drug resistance that potentiate disease outcomes are observed among the most prevalent GINs of veterinary importance. Within the five major taxonomic clades, clade Va represents a group of GINs that predominantly affect the abomasum or small intestine of ruminants. However, the development of effective broad-spectrum anthelmintics against ruminant clade Va GINs has been challenged by a lack of comprehensive druggable genome resources. Here, we first assembled draft genomes for three clade Va species (Cooperia oncophora, Trichostrongylus colubriformis, and Ostertagia ostertagi) and compared them with closely related ruminant GINs. Genome-wide phylogenetic reconstruction showed a relationship among ruminant GINs structured by taxonomic classification. Orthogroup (OG) inference and functional enrichment analyses identified 220 clade Va-specific and Va-conserved OGs, enriched for functions related to cell cycle and cellular senescence. Further transcriptomic analysis identified 61 taxonomically and functionally conserved clade Va OGs that may function as drug targets for new broad-spectrum anthelmintics. Chemogenomic screening identified 11 compounds targeting homologs of these OGs, thus having potential anthelmintic activity. In in vitro phenotypic assays, three kinase inhibitors (digitoxigenin, K-252a, and staurosporine) exhibited broad-spectrum anthelmintic activities against clade Va GINs by obstructing the motility of exsheathed L3 (xL3) or molting of xL3 to L4. These results demonstrate valuable applications of the new ruminant GIN genomes in gaining better insights into their life cycles and offer a contemporary approach to discovering the next generation of anthelmintics.IMPORTANCEGastrointestinal nematode (GIN) infections in ruminants are caused by parasites that inhibit normal function in the digestive tract of cattle, sheep, and goats, thereby causing morbidity and mortality. Coinfection and increasing drug resistance to current therapeutic agents will continue to worsen disease outcomes and impose significant production losses on domestic livestock producers worldwide. In combination with ongoing therapeutic efforts, advancing the discovery of new drugs with novel modes of action is critical for better controlling GIN infections. The significance of this study is in assembling and characterizing new GIN genomes of Cooperia oncophora, Ostertagia ostertagi, and Trichostrongylus colubriformis for facilitating a multi-omics approach to identify novel, biologically conserved drug targets for five major GINs of veterinary importance. With this information, we were then able to demonstrate the potential of commercially available compounds as new anthelmintics.

Screening and Structural Characterization of Heat Shock Response Elements (HSEs) in Entamoeba histolytica Promoters

Entamoeba histolytica (E. histolytica) exhibits a remarkable capacity to respond to thermal shock stress through a sophisticated genetic regulation mechanism. This process is carried out via Heat Shock Response Elements (HSEs), which are recognized by Heat Shock Transcription Factors (EhHSTFs), enabling fine and precise control of gene expression. Our study focused on screening for HSEs in the promoters of the E. histolytica genome, specifically analyzing six HSEs, including Ehpgp5, EhrabB1, EhrabB4, EhrabB5, Ehmlbp, and Ehhsp100. We discovered 2578 HSEs, with 1412 in promoters of hypothetical genes and 1166 in coding genes. We observed that a single promoter could contain anywhere from one to five HSEs. Gene ontology analysis revealed the presence of HSEs in essential genes for the amoeba, including cysteine proteinases, ribosomal genes, Myb family DNA-binding proteins, and Rab GTPases, among others. Complementarily, our molecular docking analyses indicate that these HSEs are potentially recognized by EhHSTF5, EhHSTF6, and EhHSTF7 factors in their trimeric conformation. These findings suggest that E. histolytica has the capability to regulate a wide range of critical genes via HSE-EhHSTFs, not only for thermal stress response but also for vital functions of the parasite. This is the first comprehensive study of HSEs in the genome of E. histolytica, significantly contributing to the understanding of its genetic regulation and highlighting the complexity and precision of this mechanism in the parasite's survival.

A Mini-Review on Elisa-Based Diagnosis of Schistosomiasis

BACKGROUND

Schistosomiasis is a neglected tropical parasitic disease caused by trematode worms of the genus schistosoma, which affects approximately 240 million people worldwide. the diagnosis of the disease can be performed by parasitological, molecular, and/or immunological methods, however, the development of new diagnostic methods still essential to guide policy decisions, monitor disease trends and assess the effectiveness of interventions.

OBJECTIVE

in this sense, the current work summarizes the findings of a systematic review regarding antigens applied in the enzyme-linked immunosorbent assay test, which were patented and published over the last ten years.

METHODS

the literature search strategy used medical subject heading (mesh) terms to define as descriptors. "schistosoma mansoni" was used in arrangement with the descriptors "immunoassay", "enzyme-linked immunosorbent assay", "elisa", and "antigens", using the "and" connector. the patent search was done using keywords, including diagnosis and schistosoma or schistosomiasis or schistosome. several databases were employed for the patent search, such as intellectual property national institute; european patent office; the united states patent and trademark office; patent scope, and google patents.

RESULTS

forty-one articles were retrieved, of which only five met the eligibility criteria. seventeen patents were taken from the databases, and a brief description of the most relevant inventions is given here.

CONCLUSION

schistosomiasis is considered the most important helminthic disease in worldwide. therefore, it is important to of searching for and develops diagnostic methods based on serology to reduce morbidity and mortality caused by the disease.

Proteomic analysis of proteins released by Tritrichomonas foetus: Identification of potential targets for the development of new diagnostic methods

Bovine trichomonosis (BT), a disease of the bovine urogenital tract, is caused by the protozoan Tritrichomonas foetus (Tf). Tf causes endometritis, infertility, and premature death of the embryo, which generates considerable economic losses. The proteins released can mediate fundamental interactions between the pathogen and the host, triggering factors associated with the symptomatology, immune evasion and pathogenesis characteristic of the species. However, little is known about the profile of the proteins released by Tf. In order to contribute to their knowledge, we performed an isolation protocol and a proteomic profiling of the supernatant (SN) content of six Tf isolates. A total of 662 proteins present in the SN of Tf were detected, out of which 121 were shared by the six isolates, while the remaining 541 were found in at least one of the isolates studied. The comparative analyses using the databases of Tf strain genome K revealed 32.9% of uncharacterized proteins. The bioinformatic analyses showed that the main molecular functions predicted were binding (47.9%) and catalytic activity (38.2%). Additionally, we performed immunodetection assays to evidence the antigenic potential of SN proteins. Interestingly, we observed great ability to detect SN proteins from all six isolates using serum from immunized mice and infected bulls. A complementary mass spectrometry assay allowed us to determine that the proteins that showed the strongest signal intensity in the immunoassays were Grp78 (A0A1J4IZS3) and Ap65 (A0A1J4JSR1). This work represents the first proteomic characterization of Tf SN proteins and their antigenic potential, which might be interesting for the future design of new diagnosis and treatment methods for BT.

Proteomic characterization of extracellular vesicles released by third stage larvae of the zoonotic parasite Anisakis pegreffii (Nematoda: Anisakidae)

Introduction

Anisakis pegreffii is a sibling species within the A. simplex (s.l.) complex requiring marine homeothermic (mainly cetaceans) and heterothermic (crustaceans, fish, and cephalopods) organisms to complete its life cycle. It is also a zoonotic species, able to accidentally infect humans (anisakiasis). To investigate the molecular signals involved in this host-parasite interaction and pathogenesis, the proteomic composition of the extracellular vesicles (EVs) released by the third-stage larvae (L3) of A. pegreffii, was characterized.

Methods

Genetically identified L3 of A. pegreffii were maintained for 24 h at 37°C and EVs were isolated by serial centrifugation and ultracentrifugation of culture media. Proteomic analysis was performed by Shotgun Analysis.

Results and discussion

EVs showed spherical shaped structure (size 65-295 nm). Proteomic results were blasted against the A. pegreffii specific transcriptomic database, and 153 unique proteins were identified. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis predicted several proteins belonging to distinct metabolic pathways. The similarity search employing selected parasitic nematodes database revealed that proteins associated with A. pegreffii EVs might be involved in parasite survival and adaptation, as well as in pathogenic processes. Further, a possible link between the A. pegreffii EVs proteins versus those of human and cetaceans’ hosts, were predicted by using HPIDB database. The results, herein described, expand knowledge concerning the proteins possibly implied in the host-parasite interactions between this parasite and its natural and accidental hosts.

Heat shock protein 60 in parasitic helminths: A role in immune responses and therapeutic applications

Heat shock protein 60 (HSP60) is an unique member of the heat shock protein family, being involved in parasite infections. To cope with harsh environments where parasites live, HSP60s are indispensable and involved in a variety of biological processes. HSP60s have relative low similarity among parasites, but their ATPase /Mg²⁺ active sites are highly conserved. The interactions of HSP60s with signaling pathway regulators in immune cells suggest a crucial role in immune responses, rendering them a potential therapeutic target. This paper reviews the current understandings of HSP60s in parasitic helminths in aspects of molecular characteristics, immunoregulatory responses and HSP60-based therapeutics.

Structural Basis of Parasitic HSP90 ATPase Inhibition by Small Molecules

Protozoan parasites are responsible for several harmful and widespread human diseases that cause high morbidity and mortality. Currently available treatments have serious limitations due to poor efficiency, strong adverse effects, and high cost. Hence, the identification of new targets and the development of specific drug therapies against parasitic diseases are urgent needs. Heat shock protein 90 (HSP90) is an ATP-dependent molecular chaperone that plays a key role in parasite survival during the various differentiation stages, spread over the vector insect and the human host, which they undergo during their life cycle. The N-terminal domain (NTD) of HSP90, containing the main determinants for ATPase activity, represents the most druggable domain for inhibitor targeting. The molecules investigated on parasite HSP90 are mainly developed from known inhibitors of the human counterpart, and they have strong limitations due to selectivity issues, accounting for the high conservation of the ATP-binding site between the parasite and human proteins. The current review highlights the recent structural progress made to support the rational design of new molecules able to effectively block the chaperone activity of parasite HSP90.

Management of potato cyst nematodes with special focus on biological control and trap cropping strategies

Potato cyst nematodes (PCNs; Globodera spp.) are one of the most difficult pests of potato to manage worldwide. Indiscriminate use of pesticides and their hazardous effects discourage the use of many chemicals for the management of PCNs. As a result, biological control agents and trap crops have received more attention from growers as safer ways to manage PCNs. The biological control agents such as Pochonia chlamydosporia, Purpureocillium lilacinum, Trichoderma spp., Pseudomonas fluorescens, Bacillus spp., Pasteuria spp., and others are recognized as potential candidates for the management of PCNs. Moreover recently, the use of trap crop Solanum sisymbriifolium also showed promise by drastically reducing soil populations of PCNs. Integration of these management strategies along with other practices including identification, conservation, and multiplication of native antagonists, will facilitate efficient management of the PCNs in potato cropping system. Some of the promising research approaches that are being used against PCNs are addressed in this review. © 2022 Society of Chemical Industry.

Transcriptomic Differences between Free-Living and Parasitic Chilodonella uncinata (Alveolata, Ciliophora)

Chilodonella uncinata is a facultatively parasitic ciliate, which can opportunistically parasitize on fish gills and fins, and sometimes even cause host mortality. Previous molecular studies of C. uncinata mainly focused on genetic diversity and molecular evolution. There are currently no transcriptome reports studying differences between free-living and parasitic C. uncinata. We addressed this by sequencing transcriptomes of these two C. uncinata lifestyle types using Smart-seq2 and Illumina HiSeq technologies. In total, 1040 differentially expressed genes (DEGs) were identified. Compared with the free-living type, 494 genes of the parasitic type were downregulated and 546 genes were upregulated. These DEGs were identified through BLAST with NCBI-nr, Swiss-Port, and Pfam databases and then annotated by GO enrichment and KEGG pathway analysis. The results showed that parasitism-related genes such as heat shock proteins (HSPs), actin I, and leishmanolysin were significantly upregulated in parasitic C. uncinata. The ciliary-related dynein heavy chain also had a higher expression in parasitic C. uncinata. Furthermore, there were significant differences in the amino acid metabolism, fatty acid metabolism, lipid metabolism, and TCA cycle. This study increases the volume of molecular data available for C. uncinata and contributes to our understanding of the mechanisms underlying the transition from a free-living to a parasitic lifestyle.

Comparative proteomics of adult Paragonimus kellicotti excretion/secretion products released in vitro or present in the lung cyst nodule

Paragonimus kellicotti is a zoonotic lung fluke infection, the agent of North American paragonimiasis, and an excellent model for other Paragonimus infections. The excretory/secretory proteins (ESP) released by parasites and presented at the parasite-host interface are frequently proposed to be useful targets for drugs and/or vaccines In vitro culture conditions may alter ESP compared to those produced in vivo. In order to investigate ESPs produced in vivo we took advantage of the fact that adult P. kellicotti reproduce in the lungs of experimentally infected gerbils in tissue cysts. We performed a mass-spectrometric analysis of adult P. kellicotti soluble somatic protein (SSPs) extracts, excreted/secreted proteins (ESPs) produced by adult worms during in vitro culture, and lung cyst fluid proteins (CFPs) from experimentally infected gerbils. We identified 2,137 P. kellicotti proteins that were present in at least two of three biological replicates and supported by at least two peptides. Among those were 1,914 proteins found in SSP, 947 in ESP and 37 in CFP. In silico analysis predicted that only 141 of the total 2,137 proteins were secreted via classical or non-classical pathways. The most abundant functional categories in SSP were storage and oxidative metabolism. The most abundant categories in ESP were proteins related to metabolism and signal transduction. The 37 parasite-related proteins in CFP belonged to 11 functional categories. The largest groups were proteins with unknown function, cytoskeletal proteins and proteasome machinery. 29 of these 37 proteins were shared among all three sample types. To our knowledge, this is the first study that compares in vitro and in vivo ESP for any Paragonimus species. This study has provided new insights into ESPs of food-borne trematodes that are produced and released in vivo. Proteins released at the host-parasite interface may help the parasite evade host immunity and may represent new targets for novel treatments or diagnostic tests for paragonimiasis.

Belowground Chemical Interactions: An Insight Into Host-Specific Behavior of Globodera spp. Hatched in Root Exudates From Potato and Its Wild Relative, Solanum sisymbriifolium

Understanding belowground chemical interactions between plant roots and plant-parasitic nematodes is immensely important for sustainable crop production and soilborne pest management. Due to metabolic diversity and ever-changing dynamics of root exudate composition, the impact of only certain molecules, such as nematode hatching factors, repellents, and attractants, has been examined in detail. Root exudates are a rich source of biologically active compounds, which plants use to shape their ecological interactions. However, the impact of these compounds on nematode parasitic behavior is poorly understood. In this study, we specifically address this knowledge gap in two cyst nematodes, Globodera pallida, a potato cyst nematode and the newly described species, Globodera ellingtonae. Globodera pallida is a devastating pest of potato (Solanum tuberosum) worldwide, whereas potato is a host for G. ellingtonae, but its pathogenicity remains to be determined. We compared the behavior of juveniles (J2s) hatched in response to root exudates from a susceptible potato cv. Desirée, a resistant potato cv. Innovator, and an immune trap crop Solanum sisymbriifolium (litchi tomato - a wild potato relative). Root secretions from S. sisymbriifolium greatly reduced the infection rate on a susceptible host for both Globodera spp. Juvenile motility was also significantly influenced in a host-dependent manner. However, reproduction on a susceptible host from juveniles hatched in S. sisymbriifolium root exudates was not affected, nor was the number of encysted eggs from progeny cysts. Transcriptome analysis by using RNA-sequencing (RNA-seq) revealed the molecular basis of root exudate-mediated modulation of nematode behavior. Differentially expressed genes are grouped into two major categories: genes showing characteristics of effectors and genes involved in stress responses and xenobiotic metabolism. To our knowledge, this is the first study that shows genome-wide root exudate-specific transcriptional changes in hatched preparasitic juveniles of plant-parasitic nematodes. This research provides a better understanding of the correlation between exudates from different plants and their impact on nematode behavior prior to the root invasion and supports the hypothesis that root exudates play an important role in plant-nematode interactions.

Dynamically expressed genes provide candidate viability biomarkers in a model coccidian

Eimeria parasites cause enteric disease in livestock and the closely related Cyclosporacayetanensis causes human disease. Oocysts of these coccidian parasites undergo maturation (sporulation) before becoming infectious. Here, we assessed transcription in maturing oocysts of Eimeria acervulina, a widespread chicken parasite, predicted gene functions, and determined which of these genes also occur in C. cayetanensis. RNA-Sequencing yielded ~2 billion paired-end reads, 92% of which mapped to the E. acervulina genome. The ~6,900 annotated genes underwent temporally-coordinated patterns of gene expression. Fifty-three genes each contributed >1,000 transcripts per million (TPM) throughout the study interval, including cation-transporting ATPases, an oocyst wall protein, a palmitoyltransferase, membrane proteins, and hypothetical proteins. These genes were enriched for 285 gene ontology (GO) terms and 13 genes were ascribed to 17 KEGG pathways, defining housekeeping processes and functions important throughout sporulation. Expression differed in mature and immature oocysts for 40% (2,928) of all genes; of these, nearly two-thirds (1,843) increased their expression over time. Eight genes expressed most in immature oocysts, encoding proteins promoting oocyst maturation and development, were assigned to 37 GO terms and 5 KEGG pathways. Fifty-six genes underwent significant upregulation in mature oocysts, each contributing at least 1,000 TPM. Of these, 40 were annotated by 215 GO assignments and 9 were associated with 18 KEGG pathways, encoding products involved in respiration, carbon fixation, energy utilization, invasion, motility, and stress and detoxification responses. Sporulation orchestrates coordinated changes in the expression of many genes, most especially those governing metabolic activity. Establishing the long-term fate of these transcripts in sporulated oocysts and in senescent and deceased oocysts will further elucidate the biology of coccidian development, and may provide tools to assay infectiousness of parasite cohorts. Moreover, because many of these genes have homologues in C. cayetanensis, they may prove useful as biomarkers for risk.

Heat Shock Proteins as Targets for Novel Antimalarial Drug Discovery

Plasmodium falciparum, the parasitic agent that is responsible for a severe and dangerous form of human malaria, has a history of long years of cohabitation with human beings with attendant negative consequences. While there have been some gains in the fight against malaria through the application of various control measures and the use of chemotherapeutic agents, and despite the global decline in malaria cases and associated deaths, the continual search for new and effective therapeutic agents is key to achieving sustainable development goals. An important parasite survival strategy, which is also of serious concern to the scientific community, is the rate at which the parasites continually develop resistance to drugs. Among the key players in the parasite's ability to develop resistance, maintain cellular integrity, and survives within an unusual environment of the red blood cells are the molecular chaperones of the heat shock proteins (HSP) family. HSPs constitute a novel avenue for antimalarial drug discovery and by exploring their ubiquitous nature and multifunctional activities, they may be suitable targets for the discovery of multi-targets antimalarial drugs, needed to fight incessant drug resistance. In this chapter, features of selected families of plasmodial HSPs that can be exploited in drug discovery are presented. Also, known applications of HSPs in small molecule screening, their potential usefulness in high throughput drug screening, as well as possible challenges are highlighted.

The Implication Inferred from the Expression of Small Heat-Shock Protein Genes in Dinoflagellate Resting Cysts Buried in Marine Sediment

Dinoflagellates are unicellular eukaryotic microalgae, occupying pivotal niches in aquatic ecosystems with great ecological, biological, and economic significance. Small heat shock proteins (sHsps) are the most omnipresent, but the least conserved, family of molecular chaperones found in all domains of life. Although their common name (small Hsp) implies to exclusively stress their heat shock-responsive function, many sHsps in fact engage in a variety of physiological processes, from cell growth and proliferation to embryogenesis, development, differentiation, apoptosis, and even to human disease prevention. Recent years have greatly expanded our understanding of sHsps in higher plants; however, comprehensive study aiming to delineate the composition and expression pattern of dinoflagellate sHsp gene family has not yet been performed. In this study, we constructed dinoflagellate-specific environmental cDNA library from marine sediment and sequenced using the third-generation sequencing technique. Screening of sHsp genes from the library returned 13 entries with complete coding regions, which were considered to be transcriptionally activated in the natural community of dinoflagellate resting cysts. All the 13 dinoflagellate sHsps consisted of a solely characteristic α-crystallin domain, covering 88–123 amino acid residues with the typical A-X-X-X-N-G-V-L motif, flanked by variable N- and C-terminal extensions. Multiple alignment revealed considerable amino acid divergence (~26.7% average similarity) among them. An unexpected close relationship was revealed between dinoflagellate and green algal sHsps in the phylogenetic tree, seemingly reflecting a close evolutionary relationship of these sHsps themselves. We confirmed that sHsp mRNAs are expressed during dormancy of the resting cyst assemblages of dinoflagellates that were buried in marine sediment, which raised the possibility that the sHsp expression is part of the machinery of maintaining the dormancy or/and the adaptation to ambient conditions of dinoflagellate resting cysts. Our results, although preliminary, gained an important glance on the universal presence of sHsps in dinoflagellates and their active expressions in the assemblage of resting cysts that were buried in the marine sediment. The essentiality of sHsps functioning in resting cysts necessitate more intensive and extensive investigations on all possible functions of Hsps in dinoflagellates, a group of protists with vital ecological and biological importance.

Transcriptome Analysis Reveals Possible Virulence Factors of Paragonimus proliferus

Objective:

To identify the possible virulence factors (VFs) of P. proliferus.

Methods:

By Illumina HiSeq 4000 RNA-Seq platform, transcriptomes of adult P. proliferus worms were sequenced to predict VFs via screening the homologues of traditional VFs of parasites based on the annotations in the functional databases. Homology analysis was also performed to screen homologous genes between P. proliferus and other four Paragonimus species (i.e., P. kellicotti, P. skrjabini, P. miyazakii and P. westermani) whose transcriptomes were downloaded from the National Center for Biotechnology Information (NCBI) database, and then the differential-expressed homologous genes (DEHGs) were screened via comparisons of P. proliferus and P. kellicotti, P. skrjabini, P. miyazakii and P. westermani, respectively. Finally, an overlap of the predicted VFs and DEHGs was performed to identify possible key VFs that do not only belong to the predicted VFs but also DEHGs.

Results:

A total of 1,509 genes of P. proliferus homologous to traditional VFs, including surface antigens (SAGs), secreted proteins (SPs), ATP-Binding Cassette (ABC) Transporters, actin-related proteins (ARPs), aminopeptidases (APases), glycoproteins (GPs), cysteine proteases (CPs), and heat shock proteins (HSPs), were identified. Meanwhile, homology analysis identified 6279 DEHGs among the five species, of which there were 48 DEHGs being mutually differentialexpressed among the four pairs of comparisons, such as MRP, Tuba 3, PI3K, WASF2, ADK, Nop56, DNAH1, PFK-2/FBPase2, Ppp1r7, SSP7. Furthermore, the overlap between the predicted VFs and DEHGs showed 97 genes of the predicted VFs that simultaneously belonged to DEHGs. Strikingly, of these 97 genes, only 26, including Chymotrypsin, Leucine APases, Cathepsin L, HSP 70, and so on, were higher expressed in P. proliferus while all the remaining were lower expressed than in the four other species.

Conclusions:

This work provides a fundamental context for further studies of the pathogenicity of P. proliferus. Most of the predicted VFs which simultaneously belonged to DEHGs were lower expressed in P. proliferus.

Comparative proteomic profiling of newly acquired, virulent and attenuated Neoparamoeba perurans proteins associated with amoebic gill disease

The causative agent of amoebic gill disease, Neoparamoeba perurans is reported to lose virulence during prolonged in vitro maintenance. In this study, the impact of prolonged culture on N. perurans virulence and its proteome was investigated. Two isolates, attenuated and virulent, had their virulence assessed in an experimental trial using Atlantic salmon smolts and their bacterial community composition was evaluated by 16S rRNA Illumina MiSeq sequencing. Soluble proteins were isolated from three isolates: a newly acquired, virulent and attenuated N. perurans culture. Proteins were analysed using two-dimensional electrophoresis coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS). The challenge trial using naïve smolts confirmed a loss in virulence in the attenuated N. perurans culture. A greater diversity of bacterial communities was found in the microbiome of the virulent isolate in contrast to a reduction in microbial community richness in the attenuated microbiome. A collated proteome database of N. perurans, Amoebozoa and four bacterial genera resulted in 24 proteins differentially expressed between the three cultures. The present LC-MS/MS results indicate protein synthesis, oxidative stress and immunomodulation are upregulated in a newly acquired N. perurans culture and future studies may exploit these protein identifications for therapeutic purposes in infected farmed fish.

Trichuris trichiura egg extract proteome reveals potential diagnostic targets and immunomodulators

Embryonated eggs are the infectious developmental stage of Trichuris trichiura and are the primary stimulus for the immune system of the definitive host. The intestinal-dwelling T. trichiura affects an estimated 465 million people worldwide with an estimated global burden of disease of 640 000 DALYs (Disability Adjusted Life Years). In Latin America and the Caribbean, trichuriasis is the most prevalent soil transmitted helminthiasis in the region (12.3%; 95% CI). The adverse health consequences impair childhood school performance and reduce school attendance resulting in lower future wage-earning capacity. The accumulation of the long-term effects translates into poverty promoting sequelae and a cycle of impoverishment. Each infective T. trichiura egg carries the antigens needed to face the immune system with a wide variety of proteins present in the shell, larvae’s surface, and the accompanying fluid that contains their excretions/secretions. We used a proteomic approach with tandem mass spectrometry to investigate the proteome of soluble non-embryonated egg extracts of T. trichiura obtained from naturally infected African green monkeys (Chlorocebus sabaeus). A total of 231 proteins were identified, 168 of them with known molecular functions. The proteome revealed common proteins families which are known to play roles in energy and metabolism; the cytoskeleton, muscle and motility; proteolysis; signaling; the stress response and detoxification; transcription and translation; and lipid binding and transport. In addition to the study of the T. trichiura non-embryonated egg proteome, the antigenic profile of the T. trichiura non-embryonated egg and female soluble proteins against serum antibodies from C. sabaeus naturally infected with trichuriasis was investigated. We used an immunoproteomic approach by Western blot and tandem mass spectrometry from the corresponding SDS-PAGE gels. Vitellogenin N and VWD and DUF1943 domain containing protein, poly-cysteine and histidine tailed protein isoform 2, heat shock protein 70, glyceraldehyde-3-phosphate dehydrogenase, actin, and enolase, were among the potential immunoactive proteins. To our knowledge, this is the first study on the T. trichiura non-embryonated egg proteome as a novel source of information on potential targets for immunodiagnostics and immunomodulators from a neglected tropical disease. This initial list of T. trichiura non-embryonated egg proteins (proteome and antigenic profile) can be used in future research on the immunobiology and pathogenesis of human trichuriasis and the treatment of human intestinal immune-related diseases.

Who came first the worm or its egg? In the case of whipworm, we know it is the egg. The infective life cycle stage of the human whipworm (Trichuris trichiura) is the primary stimulus for the immune system of the definitive host. Each infective whipworm egg carries the information needed to face the immune system of the host with a wide variety of proteins present in the shell, larvae’s surface, and the accompanying fluid that contains their excretions/secretions. We investigated the soluble proteins of the non-embryonated egg using an immunoproteomic approach and then selected the top five proteins using a series of bioinformatic analysis. We used these top five proteins to recognize potential targets for immunodiagnostics and immunomodulation while comparing them to known female worm proteins. We found that the proteins we selected were involved in lipid transport, energy and metabolism, and muscle and motility. One protein has unknown function.

Identification and Immunological Characterization of Somatic Proteins from Adults of Toxocara cati by Proteomics Technique

Background:

Toxocara cati is considered as one of the main etiological agents of toxocariasis with global and regional importance. As there is no information on proteomics of T. cati, herein, we reported the results obtained by proteomic analysis of somatic proteins extract, using a mass spectrometry (LC–MS/MS) approach.

Methods:

Somatic extract fractions were separated by two-dimensional SDS-PAGE and were electro blotted on to PVDF membranes for immunoblot analysis, then collected the immunogenic spots which response of antibodies of the paratenic hosts (mice) to the antigens (Mashhad, 2017), and analyzed by LC–MS/MS. The LC-MS/MS data were analyzed by Mascot database, Taxonomy Toxocara, and common contaminants, in Omics Center, Biotechnology Medical University of Graz (Austria, 2018).

Result:

The protein spots were isolated between 15–140 kDa ranges using 3–10 non-linear IPG strips and Brilliant Blue Coomassie. Ten proteins were characterized as immunogenic proteins, seven of them were identified and three of them were unknown proteins.

Conclusion:

This study provided additional information about the somatic antigens of T. cati, which can lead to the development of new strategies for novel immuno-modulators, drug targets, subunit vaccines and immunodiagnostic kits for toxocariasis.

Immunoproteomic Analysis of Dirofilaria repens Microfilariae and Adult Parasite Stages

Dirofilariarepens is a parasitic nematode causing a vector-borne zoonotic infection (dirofilariosis), considered an emerging problem in human and veterinary medicine. Currently, diagnosis is based on the detection of the adult parasite and microfilariae in the host tissues. However, the efficacy of tests relying on microfilariae detection is limited by microfilariae periodic occurrence. Therefore, a new reliable and affordable serological diagnostic method is needed. Better characteristic of the parasite biology and its interaction with host immune system should help to achieve this goal. This study analyzes adult and microfilariae proteomes, and the use of one-dimensional electrophoresis (1-DE) and two-dimensional electrophoresis (2-DE) proteomics, immunoproteomics, and LC-MS/MS mass spectrometry allowed us to identify 316 potentially immunogenic proteins (75 belong to adult stage, 183 to microfilariae, and 58 are common for both). Classified by their ontology, the proteins showed important similarities and differences between both parasite stages. The most frequently identified proteins are structural, metabolic, and heat shock proteins. Additionally, real-time PCR analysis of some immunogenic targets revealed significant differences between microfilariae and adult life stages. We indicated molecules involved in parasite-host interactions and discussed their importance in parasite biology, which may help to reveal potential diagnostic antigens or select drug and vaccine targets.

Proteomic analysis of soluble protein extract of adult Toxocara cati

Toxocara cati is a cat roundworm and the causative agent of toxocariasis as a cosmopolitan zoonotic disease. As no information has been reported so far, identification of T. cati proteins can be useful for the development of new diagnostic strategies. This study was conducted to identify the major proteins in the adult T. cati tegument using bi-dimensional electrophoresis (2-DE) and shotgun proteomics. A total proteins were identified, among them the metabolic enzymes were the largest group, including: Enolase, triose phosphate isomerase, fructose-bisphosphate aldolase, aldehyde dehydrogenase. The other important protein groups recognized in T. cati, belong to the HSP-family, the structure and motor proteins, such as actin. The role of these proteins have been implicated in parasite-host interactions and modulating cellular immune response, immune regulation in evasion mechanisms of the host immune response. Characterizing T. cati adult proteins play a key role not only in host-parasite interactions, but also in the discovery of drug targets, subunit vaccines against toxocariasis, immunodiagnostic kits for toxocariasis and the identification of novel immuno-modulators that can form the next generation of therapeutic possibilities for inflammatory diseases.

TrypOx, a Novel Eukaryotic Homolog of the Redox-Regulated Chaperone Hsp33 in Trypanosoma brucei

ATP-independent chaperones are widespread across all domains of life and serve as the first line of defense during protein unfolding stresses. One of the known crucial chaperones for bacterial survival in a hostile environment (e.g., heat and oxidative stress) is the highly conserved, redox-regulated ATP-independent bacterial chaperone Hsp33. Using a bioinformatic analysis, we describe novel eukaryotic homologs of Hsp33 identified in eukaryotic pathogens belonging to the kinetoplastids, a family responsible for lethal human diseases such as Chagas disease as caused by Trypanosoma cruzi, African sleeping sickness caused by Trypanosoma brucei spp., and leishmaniasis pathologies delivered by various Leishmania species. During their pathogenic life cycle, kinetoplastids need to cope with elevated temperatures and oxidative stress, the same conditions which convert Hsp33 into a powerful chaperone in bacteria, thus preventing aggregation of a wide range of misfolded proteins. Here, we focused on a functional characterization of the Hsp33 homolog in one of the members of the kinetoplastid family, T. brucei, (Tb927.6.2630), which we have named TrypOx. RNAi silencing of TrypOx led to a significant decrease in the survival of T. brucei under mild oxidative stress conditions, implying a protective role of TrypOx during the Trypanosomes growth. We then adopted a proteomics-driven approach to investigate the role of TrypOx in defining the oxidative stress response. Depletion of TrypOx significantly altered the abundance of proteins mediating redox homeostasis, linking TrypOx with the antioxidant system. Using biochemical approaches, we identified the redox-switch domain of TrypOx, showing its modularity and oxidation-dependent structural plasticity. Kinetoplastid parasites such as T. brucei need to cope with high levels of oxidants produced by the innate immune system, such that parasite-specific antioxidant proteins like TrypOx - which are depleted in mammals - are highly promising candidates for drug targeting.

Proteomic analysis of Ascocotyle longa (Trematoda: Heterophyidae) metacercariae

Ascocotyle longa is parasitic trematode with wide distribution throughout America, Europe, Africa, and Middle East. Despite the fact that this fish-borne pathogen has been considered an agent of human heterophyiasis in Brazil, the molecules involved in the host-parasite interaction remain unknown. The present study reports the proteome profile of A. longa metacercariae collected from the fish Mugil liza from Brazil. This infective stage for humans, mammals and birds was analyzed using nLC-MS/MS approach. We identified a large repertoire of proteins, which are mainly involved in energy metabolism and cell structure. Peptidases and immunogenic proteins were also identified, which might play roles in host-parasite interface. Our data provided unprecedented insights into the biology of A. longa and represent a first step to understand the natural host-parasite interaction. Moreover, as the first proteome characterized in this trematode, it will provide an important resource for future studies.

Fate of Ascaris at various pH, temperature and moisture levels

Soil-transmitted helminths (STH) are intestinal worms that infect 24% of the world's population. Stopping the spread of STH is difficult, as the eggs are resilient (can withstand high pH) and persistent (can remain viable in soils for several years). To ensure that new sanitation systems can inactivate STH, a better understanding of their resilience is required. This study assessed the inactivation of Ascaris eggs under various conditions, in terms of moisture content (MC) (<20 to >90%), temperature (20-50 °C) and pH (7-12.5). The results highlight that the exposure of Ascaris eggs to elevated pH (10.5-12.5) at temperatures ≤27.5 °C for >70 days had no effect on egg viability. Compounding effects of alkaline pH (≥10.5) or decreasing MC (<20%) was observed at 35 °C, with pH having more of an effect than decreasing MC. To accelerate the inactivation of STH, an increase in the treatment temperature is more effective than pH increase. Alkaline pH alone did not inactivate the eggs but can enhance the effect of ammonia, which is likely to be present in organic wastes.

Toxocara "omics" and the promises it holds for medicine and veterinary medicine

Toxocariasis is one of the most neglected worldwide zoonoses that is caused by larval nematode parasites of the genus Toxocara, Toxocara canis, and to a lesser extent, Toxocara cati, whose migration mechanism is still largely unknown. Fortunately, some advanced tools have been employed, such as genomics, transcriptomics, and proteomics, to better understand the molecular biology and regulatory mechanisms of Toxocara. Using genomics and transcriptomics, we can identify a large number of genes that participate in the development of Toxocara and the interaction of parasites and their hosts and can predict the functions of unknown genes by comparing them with other relevant species. Using proteomics, we can identify somatic proteins and excretory and secretory (ES) proteins that perform specific biological functions in tissue degradation, pathogen invasion, immune evasion or modulation. These "omics" techniques also can contribute enormously to the development of new drugs, vaccines and diagnostic tools for toxocariasis. In a word, by utilizing "omics", we can better understand the Toxocara and toxocariasis. In this review, we summarized the representative achievements in Toxocara and the interaction between Toxocara spp. and their hosts based on expressed sequence tags (ESTs), microarray gene expression, next-generation sequencing (NGS) technologies and liquid chromatography-tandem mass spectrometry (LC-MS/MS), hoping to better understand the molecular biology of Toxocara, and contribute to new progress in the application areas of new drugs, vaccines and diagnostic tool for toxocariasis in the future.

Transcriptome analysis of Globodera pallida from the susceptible host Solanum tuberosum or the resistant plant Solanum sisymbriifolium

A transcriptome analysis of G. pallida juveniles collected from S. tuberosum or S. sisymbriifolium 24 h post infestation was performed to provide insights into the parasitic process of this nematode. A total of 41 G. pallida genes were found to be significantly differentially expressed when parasitizing the two plant species. Among this set, 12 were overexpressed when G. pallida was parasitizing S. tuberosum and 29 were overexpressed when parasitizing S. sisymbriifolium. Out of the 12 genes, three code for secretory proteins; one is homologous to effector gene Rbp-4, the second is an uncharacterized protein with a signal peptide sequence, and the third is an ortholog of a Globodera rostochiensis effector belonging to the 1106 effector family. Other overexpressed genes from G. pallida when parasitizing S. tuberosum were either unknown, associated with a stress or defense response, or associated with sex differentiation. Effector genes namely Eng-1, Cathepsin S-like cysteine protease, cellulase, and two unknown genes with secretory characteristics were over expressed when G. pallida was parasitizing S. sisymbriifolium relative to expression from S. tuberosum. Our findings provide insight into gene regulation of G. pallida while infecting either the trap crop S. sisymbriifolium or the susceptible host, S. tuberosum.

Protein quality control machinery in intracellular protozoan parasites: hopes and challenges for therapeutic targeting

Intracellular protozoan parasites have evolved an efficient protein quality control (PQC) network comprising protein folding and degradation machineries that protect the parasite's proteome from environmental perturbations and threats posed by host immune surveillance. Interestingly, the components of PQC machinery in parasites have acquired sequence insertions which may provide additional interaction interfaces and diversify the repertoire of their biological roles. However, the auxiliary functions of PQC machinery remain poorly explored in parasite. A comprehensive understanding of this critical machinery may help to identify robust biological targets for new drugs against acute or latent and drug-resistant infections. Here, we review the dynamic roles of PQC machinery in creating a safe haven for parasite survival in hostile environments, serving as a metabolic sensor to trigger transformation into phenotypically distinct stages, acting as a lynchpin for trafficking of parasite cargo across host membrane for immune evasion and serving as an evolutionary capacitor to buffer mutations and drug-induced proteotoxicity. Versatile roles of PQC machinery open avenues for exploration of new drug targets for anti-parasitic intervention and design of strategies for identification of potential biomarkers for point-of-care diagnosis.

An immunoproteomic approach to identifying immunoreactive proteins in Leishmania infantum amastigotes using sera of dogs infected with canine visceral leishmaniasis

Visceral leishmaniasis (VL), the most severe form of leishmaniasis, is caused by Leishmania donovani and Leishmania infantum. The infected dogs with canine visceral leishmaniasis (CVL) are important reservoirs for VL in humans, so the diagnosis, treatment and vaccination of the infected dogs will ultimately decrease the rate of human VL. Proteomics and immunoproteomics techniques have facilitated the introduction of novel drug, vaccine and diagnostic targets. Our immunoproteomic study was conducted to identify new immunoreactive proteins in amastigote form of L. infantum. The strain of L. infantum (MCAN/IR/07/Moheb-gh) was obtained from CVL-infected dogs. J774 macrophage cells were infected with the L. infantum promastigotes. The infected macrophages were ruptured, and pure amastigotes were extracted from the macrophages. After protein extraction, two-dimensional gel electrophoresis was employed for protein separation followed by Western blotting. Western blotting was performed, using symptomatic and asymptomatic sera of the infected dogs with CVL. Thirteen repeatable immunoreactive spots were identified by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Some, including prohibitin, ornithine aminotransferase, annexin A4, and apolipoprotein A-I, have been critically involved in metabolic pathways, survival, and pathogenicity of Leishmania parasites. Further investigations are required to confirm our identified immunoreactive proteins as a biomarker for CVL.

Characterization and functional analysis of hsp18.3 gene in the red flour beetle, Tribolium castaneum

Small heat shock proteins (sHSPs) are diverse and mainly function as molecular chaperones to protect organisms and cells from various stresses. In this study, hsp18.3, one Tribolium castaneum species-specific shsp, has been identified. Quantitative real-time polymerase chain reaction illustrated that Tchsp18.3 is expressed in all developmental stages, and is highly expressed at early pupal and late adult stages, while it is highly expressed in ovary and fat body at the adult period. Moreover, it was up-regulated 4532 ± 396-fold in response to enhanced heat stress but not to cold stress; meanwhile the lifespan of adults in ds-Tchsp18.3 group reduced by 15.8% from control group under starvation. Laval RNA interference (RNAi) of Tchsp18.3 caused 86.1% ± 4.5% arrested pupal eclosion and revealed that Tchsp18.3 played an important role in insect development. In addition, parental RNAi of Tchsp18.3 reduced the oviposition amount by 94.7%. These results suggest that Tchsp18.3 is not only essential for the resistance to heat and starvation stress, but also is critical for normal development and reproduction in T. castaneum.

Molecular characterisation and expression analysis of two heat-shock proteins in Taenia multiceps

Background

Taenia multiceps is a harmful tapeworm and its larval form (coenurus cerebralis) is the causative agent of coenurosis, a disease affecting the health of herbivores, resulting in great economic loss to animal husbandry. Heat-shock proteins (HSPs), expressed in all prokaryotes and eukaryotes, act as molecular chaperones and can affect pathogenicity.

Methods

Herein, cDNAs of T. multiceps genes Tm-HSP60 and Tm-p36 were cloned and molecularly characterised by bioinformatics analyses. The immunogenicity and immunoreactivity of recombinant rTm-HSP60 and rTm-p36 proteins were investigated by immunoblotting and indirect ELISA was established to evaluate their serodiagnostic potential. Tissue localisation and transcriptional level at different life stages of T. multiceps were determined by immunohistochemical and quantitative real-time PCR analyses.

Result

The 533 residue rTm-HSP60 and the 314 residue rTm-p36 proteins share typical highly conserved features of HSPs. Tm-p36 shares structural characteristics with metazoan small HSPs, with two N-terminal α-crystallin domains. Compared with Tm-p36, Tm-HSP60 displayed stronger immunogenicity, and the indirect ELISA based on rTm-HSP60 exhibited a sensitivity of 83.3% and a specificity of 87.5%, while rTm-p36 was not suitable to develop indirect ELISA. Tm-HSP60 was widely distributed in all stages of T. multiceps, albeit at relatively low levels, while Tm-p36 was specifically distributed in the protoscolex and oncosphere.

Conclusions

The sequence, structural and functional analyses of these two HSPs indicates that they may play important roles in the life-cycle of T. multiceps as molecular chaperones. Tm-HSP60 displayed stronger immunogenicity compare to Tm-p36, and has the potential for antibody detection. Tm-p36 was strongly associated with the activation of oncospheres and has potential interest for vaccination.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3352-8) contains supplementary material, which is available to authorized users.

Trichinella britovi muscle larvae and adult worms: stage-specific and common antigens detected by two-dimensional gel electrophoresis-based immunoblotting

Background

Trichinella britovi is the second most common species of Trichinella that may affect human health. As an early diagnosis of trichinellosis is crucial for effective treatment, it is important to identify sensitive, specific and common antigens of adult T. britovi worms and muscle larvae. The present study was undertaken to uncover the stage-specific and common proteins of T. britovi that may be used in specific diagnostics.

Methods

Somatic extracts obtained from two developmental stages, muscle larvae (ML) and adult worms (Ad), were separated using two-dimensional gel electrophoresis (2-DE) coupled with immunoblot analysis. The positively-visualized protein spots specific for each stage were identified through liquid chromatography-tandem mass spectrometry (LC-LC/MS).

Results

A total of 272 spots were detected in the proteome of T. britovi adult worms (Ad) and 261 in the muscle larvae (ML). The somatic extracts from Ad and ML were specifically recognized by T. britovi-infected swine sera at 10 days post infection (dpi) and 60 dpi, with a total of 70 prominent protein spots. According to immunoblotting patterns and LC-MS/MS results, the immunogenic spots recognized by different pig T. britovi-infected sera were divided into three groups for the two developmental stages: adult stage-specific proteins, muscle larvae stage-specific proteins, and proteins common to both stages. Forty-five Ad proteins (29 Ad-specific and 16 common) and thirteen ML proteins (nine ML-specific and four common) cross-reacted with sera at 10 dpi. Many of the proteins identified in Ad (myosin-4, myosin light chain kinase, paramyosin, intermediate filament protein B, actin-depolymerizing factor 1 and calreticulin) are involved in structural and motor activity. Among the most abundant proteins identified in ML were 14-3-3 protein zeta, actin-5C, ATP synthase subunit d, deoxyribonuclease-2-alpha, poly-cysteine and histide-tailed protein, enolase, V-type proton ATPase catalytic and serine protease 30. Heat-shock protein, intermediate filament protein ifa-1 and intermediate filament protein B were identified in both proteomes.

Conclusions

To our knowledge, this study represents the first immunoproteomic identification of the antigenic proteins of adult worms and muscle larvae of T. britovi. Our results provide a valuable basis for the development of diagnostic methods. The identification of common components for the two developmental stages of T. britovi may be useful in the preparation of parasitic antigens in recombinant forms for diagnostic use.

Genome-wide identification of evolutionarily conserved Small Heat-Shock and eight other proteins bearing α-crystallin domain-like in kinetoplastid protists

Small Heat-Shock Proteins (sHSPs) and other proteins bearing alpha-crystallin domains (ACD) participate in defense against heat and oxidative stress and play important roles in cell cycle, cytoskeleton dynamics, and immunological and pathological mechanisms in eukaryotes. However, little is known about these proteins in early-diverging lineages of protists such as the kinetoplastids. Here, ACD-like proteins (ACDp) were investigated in genomes of 61 species of 12 kinetoplastid genera, including Trypanosoma spp. (23 species of mammals, reptiles and frogs), Leishmania spp. (mammals and lizards), trypanosomatids of insects, Phytomonas spp. of plants, and bodonids. Comparison of ACDps based on domain architecture, predicted tertiary structure, phylogeny and genome organization reveals a kinetoplastid evolutionarily conserved repertoire, which diversified prior to trypanosomatid adaptation to parasitic life. We identified 9 ACDp orthologs classified in 8 families of TryACD: four previously recognized (HSP20, Tryp23A, Tryp23B and ATOM69), and four characterized for the first time in kinetoplastids (TryACDP, TrySGT1, TryDYX1C1 and TryNudC). A single copy of each ortholog was identified in each genome alongside TryNudC1/TrypNudC2 homologs and, overall, ACDPs were under strong selection pressures at main phylogenetic lineages. Transcripts of all ACDPs were identified across the life stages of T. cruzi, T. brucei and Leishmania spp., but proteomic profiles suggested that most ACDPs may be species- and stage-regulated. Our findings establish the basis for functional studies, and provided evolutionary and structural support for an underestimated repertoire of ACDps in the kinetoplastids.

Silencing of a Meloidogyne incognita selenium-binding protein alters the cuticular adhesion of Pasteuria penetrans endospores

Pasteuria penetrans is an endospore forming hyperparasitic bacterium of the plant-pathogenic root-knot nematode, Meloidogyne incognita. For successful parasitization, the first step is adherence of bacterial endospores onto the cuticle surface of nematode juveniles. The knowledge of molecular intricacies involved during this adherence is sparse. Here, we identified a M. incognita selenium-binding protein (Mi-SeBP-1) differentially expressed during the initial interaction of M. incognita and P. penetrans, and show that it is involved in modulating parasitic adhesion of bacterial endospores onto nematode cuticle. Selenium-binding proteins (SeBPs) are selenium associated proteins important for growth regulation, tumor prevention and modulation of oxidation/reduction in cells. Although reported to be present in several nematodes, the function of SeBPs is not known in Phylum Nematoda. In situ hybridization assay localized the Mi-SeBP-1 mRNA to the hypodermal cells. RNAi-mediated silencing of Mi-SeBP-1 significantly increased the adherence of P. penetrans endospores to the nematode juvenile cuticle. Silencing of Mi-SeBP-1 did not change the nematode's ability to parasitize plants and reproduction potential within the host. These results suggest that M. incognita Mi-SeBP-1 might be involved in altering the attachment of microbial pathogens on the nematode cuticle, but is not involved in nematode-host plant interaction. This is the first report for a function of SeBP in Phylum Nematoda.

The somatic proteins of Toxocara canis larvae and excretory-secretory products revealed by proteomics

Toxocariasis is a widespread helminth infection of dogs and cats, caused by Toxocara canis and Toxocara cati larvae, respectively. Toxocara spp. can cause zoonotic infections in humans by invading tissues and organs causing pathology. Toxocara spp. larvae release excretory-secretory molecules (TES) into the body of their host that are fundamental to the host-parasite interaction and could be used as targets for novel diagnostics and vaccines. In the present study, we identified 646 T. canis proteins from TES and larval extract using 1D-SDS PAGE followed by mass spectrometry. A wide range of proteins was identified that may play a role both in the induction of the host immune response and host pathology, and in parasite metabolism and survival. Among these proteins there are potential candidates for novel diagnostics and vaccines for dogs and cats toxocariases.

Utilization of Different Omic Approaches to Unravel Stress Response Mechanisms in the Parasite Entamoeba histolytica

During its life cycle, the unicellular parasite Entamoeba histolytica is challenged by a wide variety of environmental stresses, such as fluctuation in glucose concentration, changes in gut microbiota composition, and the release of oxidative and nitrosative species from neutrophils and macrophages. The best mode of survival for this parasite is to continuously adapt itself to the dynamic environment of the host. Our ability to study the stress-induced responses and adaptive mechanisms of this parasite has been transformed through the development of genomics, proteomics or metabolomics (omics sciences). These studies provide insights into different facets of the parasite's behavior in the host. However, there is a dire need for multi-omics data integration to better understand its pathogenic nature, ultimately paving the way to identify new chemotherapeutic targets against amebiasis. This review provides an integration of the most relevant omics information on the mechanisms that are used by E. histolytica to resist environmental stresses.

Identification of immunogenic proteins of the cysticercoid of Hymenolepis diminuta

Background

A wide range of molecules are used by tapeworm metacestodes to establish successful infection in the hostile environment of the host. Reports indicating the proteins in the cestode-host interactions are limited predominantly to taeniids, with no previous data available for non-taeniid species. A non-taeniid, Hymenolepis diminuta, represents one of the most important model species in cestode biology and exhibits an exceptional developmental plasticity in its life-cycle, which involves two phylogenetically distant hosts, arthropod and vertebrate.

Results

We identified H. diminuta cysticercoid proteins that were recognized by sera of H. diminuta-infected rats using two-dimensional gel electrophoresis (2DE), 2D-immunoblotting, and LC-MS/MS mass spectrometry. Proteomic analysis of 42 antigenic spots revealed 70 proteins. The largest number belonged to structural proteins and to the heat-shock protein (HSP) family. These results show a number of the antigenic proteins of the cysticercoid stage, which were present already in the insect host prior to contact with the mammal host. These are the first parasite antigens that the mammal host encounters after the infection, therefore they may represent some of the molecules important in host-parasite interactions at the early stage of infection.

Conclusions

These results could help in understanding how H. diminuta and other cestodes adapt to their diverse and complex parasitic life-cycles and show universal molecules used among diverse groups of cestodes to escape the host response to infection.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2519-4) contains supplementary material, which is available to authorized users.

Characterization and expression analysis of a new small heat shock protein Hsp20.4 from Eimeria tenella

Small heat shock proteins (sHsps) are ubiquitous and diverse molecular chaperones. Found in almost all organisms, they regulate protein refolding and protect cells from stress. Until now, no sHsp has been characterized in Eimeria tenella. In this study, the novel EtsHsp20.4 gene was cloned from E. tenella by rapid amplification of cDNA ends based on a previously identified expressed sequence tag. The full-length cDNA was 1019bp in length and contained an open reading frame of 558bp that encoded a 185-amino acid polypeptide with a calculated molecular weight of 20.4 kDa. The EtsHsp20.4 protein contained a distinct HSP20/alpha-crystallin domain that is the key determinant of their function as molecular chaperones and belongs to the HSP20 protein family. EtsHsp20.4 mRNA levels were higher in sporulated oocysts than in sporozoites or second-generation merozoites by real-time quantitative PCR, the transcription of EtsHsp20.4 was barely detectable in unsporulated oocysts. Immunolocalization with EtsHsp20.4 antibody showed that EtsHsp20.4 was mainly located on the surface of sporozoites, first-generation merozoites and second-generation merozoites. Following the development of parasites in DF-1 cells, EtsHsp20.4 protein was uniformly dispersed in trophozoites, immature schizonts, and mature schizonts. Malate dehydrogenase thermal aggregation assays indicated that recombinant EtsHsp20.4 had molecular chaperone activity in vitro. These results suggested that EtsHsp20.4 might be involved in sporulation in external environments and intracellular growth of the parasite in the host.

Comparative proteomics of hydatid fluids from two Echinococcus multilocularis isolates

The hydatid fluid (HF) that fills Echinococcus multilocularis metacestode vesicles is a complex mixture of proteins from both parasite and host origin. Here, a LC-MS/MS approach was used to compare the HF composition of E. multilocularis H95 and G8065 isolates (EmH95 and EmG8065, respectively), which present differences in terms of growth and fertility. Overall, 446 unique proteins were identified, 392 of which (88%) were from parasite origin and 54 from culture medium. At least 256 of parasite proteins were sample exclusive, and 82 of the 136 shared proteins presented differential abundance between E. multilocularis isolates. The parasite's protein repertoires in EmH95 and EmG8065 HF samples presented qualitative and quantitative differences involving antigens, signaling proteins, proteolytic enzymes, protease inhibitors and chaperones, highlighting intraspecific singularities that could be correlated to biological features of each isolate. The repertoire of medium proteins found in the HF was also differential between isolates, and the relevance of the HF exogenous protein content for the parasite's biology is discussed. The repertoires of identified proteins also provided potential molecular markers for important biological features, such as parasite growth rate and fertility, as well potential protein targets for the development of novel diagnostic and treatment strategies for alveolar echinococcosis.

BIOLOGICAL SIGNIFICANCE

E. multilocularis metacestode infection of mammal hosts involve complex interactions mediated by excretory/secretory (ES) products. The hydatid fluid (HF) that fills the E. multilocularis metacestode vesicles contains complex repertoires of parasite ES products and host proteins that mediate important molecular interactions determinant for parasite survival and development, and, consequently, to the infection outcome. HF has been also extensively reported as the main source of proteins for the immunodiagnosis of echinococcosis. The performed proteomic analysis provided a comprehensive profiling of the HF protein composition of two E. multilocularis isolates. This allowed us to identify proteins of both parasite and exogenous (medium) origin, many of which present significant differential abundances between parasite isolates and may correlate to their differential biological features, including fertility and growth rate.

Leishmania donovani chaperonin 10 regulates parasite internalization and intracellular survival in human macrophages

Protozoa of the genus Leishmania infect macrophages in their mammalian hosts causing a spectrum of diseases known as the leishmaniases. The search for leishmania effectors that support macrophage infection is a focus of significant interest. One such candidate is leishmania chaperonin 10 (CPN10) which is secreted in exosomes and may have immunosuppressive properties. Here, we report for the first time that leishmania CPN10 localizes to the cytosol of infected macrophages. Next, we generated two genetically modified strains of Leishmania donovani (Ld): one strain overexpressing CPN10 (CPN10+++) and the second, a CPN10 single allele knockdown (CPN10+/-), as the null mutant was lethal. When compared with the wild-type (WT) parental strain, CPN10+/- Ld showed higher infection rates and parasite loads in human macrophages after 24 h of infection. Conversely, CPN10+++ Ld was associated with lower initial infection rates. This unexpected apparent gain-of-function for the knockdown could have been explained either by enhanced parasite internalization or by enhanced intracellular survival. Paradoxically, we found that CPN10+/- leishmania were more readily internalized than WT Ld, but also displayed significantly impaired intracellular survival. This suggests that leishmania CPN10 negatively regulates the rate of parasite uptake by macrophages while being required for intracellular survival. Finally, quantitative proteomics identified an array of leishmania proteins whose expression was positively regulated by CPN10. In contrast, many macrophage proteins involved in innate immunity were negatively regulated by CPN10. Taken together, these findings identify leishmania CPN10 as a novel effector with broad based effects on macrophage cell regulation and parasite survival.

Proteomic analysis and immunodetection of antigens from early developmental stages of Trichinella spiralis

Trichinella spiralis is an ubiquitous parasitic nematode that lives in muscle tissue of many hosts and causes trichinellosis in humans. Numerous efforts have been directed at specific detection of this infection and strategies for its control. TSL-1 and other antigens, mainly from muscle larvae (ML), have been used to induce partial protection in rodents. An improvement in protective immunity may be achieved by using antigens from other parasite stages. Further, identification of other parasite antigens may provide insights into their role in the host-parasite interaction. In this study, T. spiralis antigens from early developmental parasite stages, namely ML and pre-adult (PA) obtained at 6h, 18h and 30h post-infection, were identified by proteomic and mass spectrometry analyses. Our findings showed a differential expression of several proteins with molecular weights in the range of 13-224kDa and pI range of 4.54-9.89. Bioinformatic analyses revealed a wide diversity of functions in the identified proteins, which include structural, antioxidant, actin binding, peptidyl prolyl cis-trans isomerase, motor, hydrolase, ATP binding, magnesium and calcium binding, isomerase and translation elongation factor. This, together with the differential recognition of antigens from these parasite stages by antibodies present in intestinal fluid, in supernatants from intestinal explants, and in serum samples from mice infected with T. spiralis or re-infected with this parasite, provides information that may lead to alternatives in the design of vaccines against this parasite or for modulation of immune responses.