Disruption of insect immunity using analogs of the pleiotropic insect peptide hormone Neb-colloostatin: a nanotech approach for pest control II.

This work continues our studies on the pleiotropic activity of the insect peptide Neb-colloostatin in insects. In vivo immunological bioassays demonstrated that hemocytotoxic analogs of Neb-colloostatin injected into Tenebrio molitor significantly reduced the number of hemocytes in the hemolymph and impaired phagocytosis, nodulation and phenoloxidase activities in the insects. Among the analogs tested, [Ala1]-,[Val1]-, [Hyp4]- and [Ach4]-colloostatin were particularly potent in disrupting cellular immunity in larvae, pupae and adult insects. This result suggests that the most effective analogs showed increases in the bioactivity period in the hemolymph of insects when compared to Neb-colloostatin. Recently, we demonstrated that it is possible to introduce Neb-colloostatin through the cuticle of an insect into the hemolymph when the peptide is coupled with nanodiamonds. In this study, we showed that [Ala1]-, [Val1]-, [Hyp4]- and [Ach4]-colloostatin, when complexed with nanodiamonds, may also pass through the cuticle into the hemolymph and induce long-term impairments of immunity in T. molitor at all developmental stages. Studies on the tissue selectivity and effectiveness of Neb-colloostatin analogs and efficient methods for their introduction into insects may contribute to the development of eco-friendly pest control methods based on bioactive peptidomimetics.

[Nanodiamonds: unique nanoparticles for use in biomedicine and biotechnology]. / Nanodiamenty: unikalne nanoczasteczki do zastosowania w biomedycynie i biotechnologii.

Nanodiamonds are ultra-fine diamond particles, which due to their nano-scale size, unique physico-chemical properties, and a large ratio of easily chemically modifiable surface to volume, are of interest to biologists, chemists and physicists. This work is a review of the literature on their preparation, properties and perspectives related to the possibility of their use in biomedical sciences. The high biocompatibility of nanodiamonds, confirmed by a number of in vivo and in vitro studies, distinguishes them from other nanoparticles and allows their use as a neutral system for transporting biologically active compounds. Such nanoparticles can be used as carriers of peptides, proteins, nucleic acids, drugs or other synthetic compounds that will cause the intended biological effect in the body, in bioimaging and tissue engineering. Promising results of studies on different biological models suggest practical applications of nanotechnological solutions based on nanodiamonds.

Non-cytotoxic hydroxyl-functionalized exfoliated boron nitride nanoflakes impair the immunological function of insect haemocytes in vivo.

To induce the water solubility of hexagonal boron nitride (h-BN), we exfoliated and functionalized bulk h-BN with hydroxyl groups (h-BN-OH-n). Short-term studies showed that h-BN-OH-n induced low cytotoxicity in different models: insect haemocytes (in vivo), human erythrocytes and mouse fibroblasts (in vitro). We also demonstrated that Alexa Fluor 647-h-BN-OH-n administered topically to the insects passed through the cuticle barrier and was phagocytosed by haemocytes. Nanoflakes did not affect the haemocyte cell membrane and did not interfere with the phagocytosis of latex beads. Long-term immunoassays showed that h-BN-OH-n, despite not inducing haemocytotoxicity, impaired nodulation, the most important cellular immune response in insects. The haemocytes exposed to h-BN-OH-n and then to bacteria differed in morphology and adhesiveness from the haemocytes exposed only to bacteria and exhibited the same morphology and adhesiveness as the control haemocytes. The h-BN-OH-n-induced decrease in nodulation can therefore result from the reduced ability of haemocytes to recognize bacteria, migrate to them or form microaggregates around them, which can lead to dysfunction of the immune system during pathogen infection. Long-term in vivo studies with animal models are still necessary to unambiguously confirm that h-BN is biocompatible and useful for application as a platform for drug delivery or for bioimaging.

Impairment of the immune response after transcuticular introduction of the insect gonadoinhibitory and hemocytotoxic peptide Neb-colloostatin: A nanotech approach for pest control.

This article shows that nanodiamonds can transmigrate through the insect cuticle easily, and the doses used were not hemocytotoxic and did not cause inhibition of cellular and humoral immune responses in larvae, pupae and adults of Tenebrio molitor. The examination of the nanodiamond biodistribution in insect cells demonstrated the presence of nanodiamond aggregates mainly in hemocytes, where nanoparticles were efficiently collected as a result of phagocytosis. To a lesser extent, nanodiamond aggregates were also detected in fat body cells, while they were not observed in Malpighian tubule cells. We functionalized nanodiamonds with Neb-colloostatin, an insect hemocytotoxic and gonadoinhibitory peptide, and we showed that this conjugate passed through the insect cuticle into the hemolymph, where the peptide complexed with the nanodiamonds induced apoptosis of hemocytes, significantly decreased the number of hemocytes circulating in the hemolymph and inhibited cellular and humoral immune responses in all developmental stages of insects. The results indicate that it is possible to introduce a peptide that interferes with the immunity and reproduction of insects to the interior of the insect body by means of a nanocarrier. In the future, the results of these studies may contribute to the development of new pest control agents.