Exploring the Potential of Venom from Nasonia vitripennis as Therapeutic Agent with High-Throughput Screening Tools.

The venom from the ectoparasitoid wasp Nasonia vitripennis (Hymenoptera: Pteromalidae) contains at least 80 different proteins and possibly even more peptides or other small chemical compounds, demonstrating its appealing therapeutic application. To better understand the dynamics of the venom in mammalian cells, two high-throughput screening tools were performed. The venom induced pathways related to an early stress response and activated reporters that suggest the involvement of steroids. Whether these steroids reside from the venom itself or show an induced release/production caused by the venom, still remains unsolved. The proinflammatory cytokine IL-1ß was found to be down-regulated after venom and LPS co-treatment, confirming the anti-inflammatory action of N. vitripennis venom. When analyzing the expression levels of the NF-κB target genes, potentially not only the canonical but also the alternative NF-κB pathway can be affected, possibly explaining some counterintuitive results. It is proposed that next to an NF-κB binding site, the promoter of the genes tested by the PCR array may also contain binding sites for other transcription factors, resulting in a complex puzzle to connect the induced target gene with its respective transcription factor. Interestingly, Nasonia venom altered the expression of some drug targets, presenting the venom with an exciting therapeutical potential.

Reproduction of honeybee workers is regulated by epidermal growth factor receptor signaling.

Eusocial insect societies display a remarkable reproductive division of labor between a single fertile queen and thousands of largely sterile workers. In most species, however, the workers retain the capacity to reproduce, particularly in queenless colonies where typically many workers lay eggs. As yet, the molecular determinants that initiate this shift in worker fertility are still poorly documented. By using RNA interference we here demonstrate that the knockdown of epidermal growth factor receptor, a gene which was previously shown to be involved in queen-worker caste differentiation, also induces reproduction in worker honeybees (Apis mellifera). These data show that worker fertility and queen-worker caste determination partly rely on the same gene regulatory networks, thereby providing a major breakthrough in our understanding of the molecular determinants of the social insects' spectacular reproductive division of labor.

Early changes in the pupal transcriptome of the flesh fly Sarcophagha crassipalpis to parasitization by the ectoparasitic wasp, Nasonia vitripennis.

We investigated changes in the pupal transcriptome of the flesh fly Sarcophaga crassipalpis, 3 and 25 h after parasitization by the ectoparasitoid wasp, Nasonia vitripennis. These time points are prior to hatching of the wasp eggs, thus the results document host responses to venom injection, rather than feeding by the wasp larvae. Only a single gene appeared to be differentially expressed 3 h after parasitization. However, by 25 h, 128 genes were differentially expressed and expression patterns of a subsample of these genes were verified using RT-qPCR. Among the responsive genes were clusters of genes that altered the fly's metabolism, development, induced immune responses, elicited detoxification responses, and promoted programmed cell death. Envenomation thus clearly alters the metabolic landscape and developmental fate of the fly host prior to subsequent penetration of the pupal cuticle by the wasp larva. Overall, this study provides new insights into the specific action of ectoparasitoid venoms.

The role of serine- and metalloproteases in Nasonia vitripennis venom in cell death related processes towards a Spodoptera frugiperda Sf21 cell line.

Proteases are predominant venom components of the ectoparasitoid Nasonia vitripennis. Two protease families, serine proteases and metalloproteases were examined for their possible cytotoxic functions in the Spodoptera frugiperda (Sf21) cell line using protease inhibitors that inactivate one or both protease families. Viability assays on adherent cells indicated that both protease families are among the main cytotoxic compounds of N. vitripennis venom. However, viability assays and flow cytometry performed on suspension cells 24h after envenomation revealed that inactivation of metalloproteases did not improve cell survival. These results indicate that both protease families may have tissue specific functions. Time course experiments indicate that serine proteases of N. vitripennis venom are responsible for inducing apoptosis in the Sf21 cell line. However, other venom compounds could also be involved in this process and different cell death pathways may take over when a specific type of cell death is inhibited. During parasitation of their natural hosts, both protease families may possibly function in immune related processes and tissue destruction, enabling venom distribution. Overall, this study provides important insights into the functions of serine and metalloproteases in the venom of N. vitripennis.

Worker honeybee sterility: a proteomic analysis of suppressed ovary activation.

Eusocial behavior is extensively studied in the honeybee, Apis mellifera, as it displays an extreme form of altruism. Honeybee workers are generally obligatory sterile in a bee colony headed by a queen, but the inhibition of ovary activation is lifted upon the absence of queen and larvae. Worker bees are then able to develop mature, viable eggs. The detailed repressive physiological mechanisms that are responsible for this remarkable phenomenon are as of yet largely unknown. Physiological studies today mainly focus on the transcriptome, while the proteome stays rather unexplored. Here, we present a quantitative 2-dimensional differential gel electrophoresis comparison between activated and inactivated worker ovaries and brains of reproductive and sterile worker bees, including a spot map of ovaries, containing 197 identified spots. Our findings suggest that suppression of ovary activation might involve a constant interplay between primordial oogenesis and subsequent degradation, which is probably mediated through steroid and neuropeptide hormone signaling. Additionally, the observation of higher viral protein loads in both the brains and ovaries of sterile workers is particularly noteworthy. This data set will be of great value for future research unraveling the physiological mechanisms underlying the altruistic sterility in honeybee workers.