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This letter comments on a recent article by Halawani et al. (10.1016/j.xphs.2021.07.017), which claimed a complex hydrogel formulation of thiamine nanospheres is a topical insect repellent. The authors did not thoroughly review the extensive prior literature on the subject that found no evidence of repellency for thiamine, and the experiment described lacked negative controls. Its results are not conclusive. [ABSTRACT FROM AUTHOR]

Background Insects are touted as a “food of the future” due to their lower environmental footprint relative to traditional livestock, raising interest in entomophagy as a sustainable diet. As such, they appeared at future-food themed Universal Exposition 2015 in Milan, Italy, in which 145 countries presented their nations’ food culture and contributions to innovative food science and technology. Scope and approach The presence and absence of entomophagy in all the national and themed pavilions of Expo 2015 and the way developing and developed nations differed in their presentation of insects were analyzed as a microcosm of global attitudes to insects as food and the barriers towards its wider adoption. Key findings and conclusions Only Belgium and the Netherlands presented insects in their vision for the future, and only Angola as traditional cuisine. Nations noted for active entomophagy today such as Mexico and Thailand did not mention insects at all. Efforts to serve insects faced obstacles in Italian import restrictions, which changed by the event's end. Expo 2015 illustrates challenges in promoting global entomophagy, including the need for improved rearing methods, the risks of associating insects with starvation scenarios, and the preference of Westerners for processed insects over whole. [ABSTRACT FROM AUTHOR]

The Phasmatodea (stick insects) have multiple, endogenous, highly expressed copies of glycoside hydrolase family 9 (GH9) genes. The purpose for retaining so many was unknown. We cloned and expressed the enzymes in transfected insect cell lines, and tested the individual proteins against different plant cell wall component poly- and oligosaccharides. Nearly all isolated enzymes were active against carboxymethylcellulose, however most could also degrade glucomannan, and some also either xylan or xyloglucan. The latter two enzyme groups were each monophyletic, suggesting the evolution of these novel substrate specificities in an early ancestor of the order. Such enzymes are highly unusual for Metazoa, for which no xyloglucanases had been reported. Phasmatodea gut extracts could degrade multiple plant cell wall components fully into sugar monomers, suggesting that enzymatic breakdown of plant cell walls by the entire Phasmatodea digestome may contribute to the Phasmatodea nutritional budget. The duplication and neofunctionalization of GH9s in the ancestral Phasmatodea may have enabled them to specialize as folivores and diverge from their omnivorous ancestors. The structural changes enabling these unprecedented activities in the cellulases require further study. [ABSTRACT FROM AUTHOR]

A Diffusion of Innovations framework is used to review entomophagy, the human consumption of insects, and its promotion. Overemphasis on changing values and unrealistic goals of insects as alternative to meat hampered entomophagy's diffusion. Supply-side developments to fight passive rejection are essential before a majority of consumers will accept insects as food. Marketing insects appropriately or using them as livestock feed will also facilitate diffusion. [ABSTRACT FROM AUTHOR]

Highlights: [•] A cellulase enzyme and several cDNA sequences for cellulases were isolated from stick insects (Phasmatodea). [•] Phasmids produce beta-1,4-endoglucanases endogenously. [•] Phasmatodea cellulase enzymes are similar to those of other polyneopterans. [•] The anterior midgut of the phasmid is the primary location of cellulose digestion by the isolated enzyme. [•] The ubiquity and importance of cellulases in obligate leaf-eaters are greater than once thought. [ABSTRACT FROM AUTHOR]

The comparative analysis of innate immunity across different insect taxa has revealed unanticipated evolutionary plasticity, providing intriguing examples of immunity-related effector gene expansion and loss. Phasmatodea, the stick and leaf insects, is an order of hemimetabolous insects that can provide insight into ancestral innate immunity genes lost by later insect clades. We injected the stick insect Peruphasma schultei with a mixture of microbial elicitors to activate a strong immune response, followed by RNA-Seq analysis to screen for induced immunity-related effector genes. This revealed a highly diverse spectrum of antimicrobial peptides (AMPs) belonging to the attacin, coleoptericin, defensin, thaumatin, and tachystatin families. In addition, we identified a large group of short, cysteine-rich putative AMPs, some of which were strongly elicited. The immunity-related effector gene repertoire also included c-type and i-type lysozymes and several pattern-recognition proteins, such as proteins that recognize Gram-negative bacteria and peptidoglycans. Finally, we identified 45 hemolymph lipopolysaccharide-binding protein sequences, an unusually large number for insects. Taken together, our results indicate that at least some phasmids synthesize a broad spectrum of diverse AMPs that deserve further in-depth analysis. • The stick insect Peruphasma schultei has a strong immune response to microbial challenges. • Phasmatodea have a greater diversity of antimicrobial peptides than related insects. • These include attacins, coleoptericins, defensins, thaumatins, and tachystatins. • They express a large number of hemolymph lipopolysaccharide-binding proteins. [ABSTRACT FROM AUTHOR]

Ensuring food security in the developing world faces new challenges as climate change and population growth strain resources. Genetically modified (GM) crops are a promising technology but face opposition due to perceptions of possible health risks and external interests, which ultimately affect trade policies between nations. Additionally, the lack of appropriate infrastructure in food insecure regions—poor access to financing, inadequate government support for agricultural extension, and unenforced laws on land tenure—make growers reluctant to adopt new technologies. In this paper, we present these themes and their interactions to help inform the discussion on the adoption of GM technology in the developing world. We focus our review on Sub-Saharan Africa, as it is often the target of new agricultural redevelopment programs from developed nations. [ABSTRACT FROM AUTHOR]