Varroa destructor from the Laboratory to the Field: Control, Biocontrol and IPM Perspectives—A Review

Varroadestructor is a real challenger for beekeepers and scientists: fragile out of the hive, tenacious inside a bee colony. From all the research done on the topic, we have learned that a better understanding of this organism in its relationship with the bee but also for itself is necessary. Its biology relies mostly on semiochemicals for reproduction, nutrition, or orientation. Many treatments have been developed over the years based on hard or soft acaricides or even on biocontrol techniques. To date, no real sustainable solution exists to reduce the pressure of the mite without creating resistances or harming honeybees. Consequently, the development of alternative disruptive tools against the parasitic life cycle remains open. It requires the combination of both laboratory and field results through a holistic approach based on health biomarkers. Here, we advocate for a more integrative vision of V. destructor research, where in vitro and field studies are more systematically compared and compiled. Therefore, after a brief state-of-the-art about the mite’s life cycle, we discuss what has been done and what can be done from the laboratory to the field against V. destructor through an integrative approach.

Recombinant cystatin-like protein-based competition ELISA for Trichinella spiralis antibody test in multihost sera

Objectives Trichinella spiralis is a zoonotic parasite with a complex parasitic life cycle and exposed to animals or humans by infectious meat. To control transmissions of T. spiralis through the food chain to humans, sensitive and selective multihost sera-diagnosis is urgent needed for monitoring T. spiralis exposure. Methods A competition enzyme-linked immunosorbent assay (cELISA) for T. spiralis infection diagnosis in multihost sera was developed based on recombinant cystatin-like protein (rCLP-cELISA) as well as monoclonal antibodies. The sensitivity and accuracy of the rCLP-cELISA were quantified using swine (n = 1316), mice (n = 189) and human (n = 157) serum samples. T. spiralis-antibody targeting test ability of the rCLP-cELISA in swine (n = 22) and human (n = 36), instead of other parasites or viruses antibodies, was evaluated. Results The rCLP-cELISA showed high agreement with commercial ELISA kits in field swine sera assessed by Cohen’s kappa value (κ = 0.7963). And it showed 100% specificity in human trichinellosis detection with sensitivity of 96.49%, no cross-reaction with other parasite or virus infections, and high positive detection rate of 87.5% in low-dose infected swine. Besides, the rCLP-cELISA exhibited potential in the detection of T. spiralis, T. nelsoni and Trichinella T8 infections. Conclusions The rCLP-cELISA can be used for T. spiralis-associated antibody test in multihost sera.

Sex-specific glycosylation of secreted immunomodulatory proteins in the filarial nematode Brugia malayi

The extended persistence of filarial nematodes within a host suggests immunomodulatory mechanisms that allow the parasites to resist or evade the host immune response. There is increasing evidence for immunomodulatory glycans expressed by a diversity of parasitic worms. In this study, we integrate multiple layers of the host-parasite interface to investigate the glycome of a model filarial parasite, Brugia malayi. We report a significant overrepresentation of terminal GalNAc moieties in adult female worms coupled with an overall upregulation in O-glycosylation, T-antigen expression, and a bias for galactose containing glycans. Adult males preferentially displayed a bias for terminal GlcNAc containing glycans, and fucosylated epitopes. Subsequent proteomic analysis confirmed sex-biases in protein glycosylation and highlighted the sex-specific glycosylation of well characterized immunomodulators expressed and secreted by B. malayi. We identify sex-specific effectors at that interface and suggest approaches to selectively interfere with the parasitic life cycle and potentially control transmission.

Are Antarctic Nanohaloarchaeota Emerging Viral Lineages?

A recent report in PNAS that Candidatus Nanohaloarchaeum antarcticus requires haloarchaeon Halorubrum lacusprofundi for growth expands the list of known symbiotic or parasitic associations between the members of DPANN archaea, which are relatively small cells with reduced genomes and limited metabolic capacity, and free-living archaea. In line with previous studies addressing the enigmatic mechanism(s) for the transfer of metabolites from Ignicoccus hospitalis to Nanoarchaeum equitans, this new study presents additional evidence supporting a direct cytoplasmic connection facilitated by the fusion of parasite’s membrane with that of its host. Here I show that this novel mechanism for accessing the host resources by a membrane fusing mechanism, which eliminates the need for sophisticated multivalent transport systems, is fundamentally similar to that employed by several viral lineages. These new findings support an evolutionary model on the origin of incipient viral lineages from parasitic cellular lineages that started their parasitic life cycle by fusing with their host cells.

Structure-Reactivity Relationships on Substrates and Inhibitors of the Lysine Deacylase Sirtuin 2 from Schistosoma Mansoni (SmSirt2)

The only drug for treatment of Schistosomiasis is Praziquantel, and the possible emergence of resistance makes research on novel therapeutic agents necessary. Targeting of Schistosoma mansoni epigenetic enzymes, which regulate the parasitic life cycle, emerged as promising approach. Due to the strong effects of human Sirtuin inhibitors on parasite survival and reproduction, Schistosoma sirtuins were postulated as therapeutic targets. In vitro testing of synthetic substrates of S. mansoni Sirtuin 2 (SmSirt2) and kinetic experiments on a myristoylated peptide demonstrated lysine long chain deacylation as an intrinsic SmSirt2 activity for the first time. Focused in vitro screening of the GSK Kinetobox library and structure-activity relationships (SAR) of identified hits, led to the first SmSirt2 inhibitors with activity in the low micromolar range. Several SmSirt2 inhibitors showed potency against both larval schistosomes (viability) and adult worms (pairing, egg laying) in culture without general toxicity to human cancer cells.<br>

Structure-Reactivity Relationships on Substrates and Inhibitors of the Lysine Deacylase Sirtuin 2 from Schistosoma Mansoni (SmSirt2)

The only drug for treatment of Schistosomiasis is Praziquantel, and the possible emergence of resistance makes research on novel therapeutic agents necessary. Targeting of Schistosoma mansoni epigenetic enzymes, which regulate the parasitic life cycle, emerged as promising approach. Due to the strong effects of human Sirtuin inhibitors on parasite survival and reproduction, Schistosoma sirtuins were postulated as therapeutic targets. In vitro testing of synthetic substrates of S. mansoni Sirtuin 2 (SmSirt2) and kinetic experiments on a myristoylated peptide demonstrated lysine long chain deacylation as an intrinsic SmSirt2 activity for the first time. Focused in vitro screening of the GSK Kinetobox library and structure-activity relationships (SAR) of identified hits, led to the first SmSirt2 inhibitors with activity in the low micromolar range. Several SmSirt2 inhibitors showed potency against both larval schistosomes (viability) and adult worms (pairing, egg laying) in culture without general toxicity to human cancer cells.<br>

Structure-Reactivity Relationships on Substrates and Inhibitors of the Lysine Deacylase Sirtuin 2 from Schistosoma Mansoni (SmSirt2)

The standard drug for treatment of the neglected disease Schistosomiasis is Praziquantel, and the possible emergence of resistance to this treatment makes the research on novel therapeutic agents necessary and urgent. To this end, the targeting of <i>Schistosoma mansoni </i>epigenetic enzymes, which regulate the parasitic life cycle, emerged as promising approach. Due to strong effects of human Sirtuin inhibitors on parasite survival and reproduction, <i>Schistosoma </i>sirtuins were postulated as potential therapeutic targets. <i>In vitro</i> testing of synthetic substrates of <i>Sm</i>Sirt2 and kinetic experiments on a myristoylated peptide newly demonstrated lysine long chain deacylation as an intrinsic <i>Sm</i>Sirt2 activity in addition to the known deacetylation. Focused <i>in vitro</i> screening of the GSK Kinetobox library and structure-activity relationships (SAR) of identified hits, led to the first <i>Sm</i>Sirt2 inhibitors with activity in the low micromolar range. Several <i>Sm</i>Sirt2 inhibitors showed potency against both larval schistosomes (viability) and adult worms (pairing, egg laying) in culture without general toxicity to human cancer cells. <br>