Growing antimicrobial resistance has prompted researchers to identify new natural molecules with antimicrobial potential. In this perspective, attention has been focused on biopolymers that could ...also be functional in the medical field. Chitin is the second most abundant biopolymer on Earth and with its deacetylated derivative, chitosan, has several applications in biomedical and pharmaceutical fields. Currently, the main source of chitin is the crustacean exoskeleton, but the growing demand for these polymers on the market has led to search for alternative sources. Among these, insects, and in particular the bioconverter Hermetia illucens, is one of the most bred. Chitin can be extracted from larvae, pupal exuviae and dead adults of H. illucens, by applying chemical methods, and converted into chitosan. Fourier-transformed infrared spectroscopy confirmed the identity of the chitosan produced from H. illucens and its structural similarity to commercial polymer. Recently, studies showed that chitosan has intrinsic antimicrobial activity. This is the first research that investigated the antibacterial activity of chitosan produced from the three developmental stages of H. illucens through qualitative and quantitative analysis, agar diffusion tests and microdilution assays, respectively. Our results showed the antimicrobial capacity of chitosan of H. illucens, opening new perspectives for its use in the biological area.
Due to their properties and applications, the growing demand for chitin and chitosan has stimulated the market to find more sustainable alternatives to the current commercial source (crustaceans). ...Bioconverter insects, such as Hermetia illucens, are the appropriate candidates, as chitin is a side stream of insect farms for feed applications. This is the first report on production and characterization of chitin and chitosan from different biomasses derived from H. illucens, valorizing the overproduced larvae in feed applications, the pupal exuviae and the dead adults. Pupal exuviae are the best biomass, both for chitin and chitosan yields and for their abundance and easy supply from insect farms. Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscope analysis revealed the similarity of insect-derived polymers to commercial ones in terms of purity and structural morphology, and therefore their suitability for industrial and biomedical applications. Its fibrillary nature makes H. illucens chitin suitable for producing fibrous manufacts after conversion to chitin nanofibrils, particularly adults-derived chitin, because of its high crystallinity. A great versatility emerged from the evaluation of the physicochemical properties of chitosan obtained from H. illucens, which presented a lower viscosity-average molecular weight and a high deacetylation degree, fostering its putative antimicrobial properties.
Organic waste is a rapidly increasing problem due to the growth of the agricultural production needed to meet global food demands. Development of sustainable waste management solutions is essential. ...Black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae) (BSF), larvae are voracious consumers of a wide range of organic materials ranging from fruits and vegetables to animal remains, and manure. Thanks to this ability and considering the larval high protein and lipid content, BSF larvae are a useful additive in animal feeds and biodiesel production. Unfortunately, the feasibility of using the black soldier fly as a tool for waste valorization and feed production has primarily been investigated at the benchtop scale. Thus, mobilization of current practices to an industrial scale is challenging because scaling up from small laboratory studies to large industrial studies is not necessarily linear. The goal of this study was to demonstrate the ability of the BSF to recycle organic waste at an industrial scale. To accomplish this goal, three organic waste streams were used (e.g., apples, bananas, and spent grain from a brewery) to test six diet treatments (1) apple, (2) banana, (3) spent grain, (4) apple and banana, (5) apple and spent grain, and (6) banana and spent grain. Working at scale of 10,000 BSF larvae life history traits, waste valorization, protein and lipid profiles were measured for each diet treatment. Differences were recorded across all variables, except substrate conversion, for larvae fed on fruit and spent grain (alone or with fruit). Growth rate significantly differed across treatments; larvae reared on spent grain grew twice as fast as those fed apples alone, but those reared on the apple and spent grain mixture produced twice as much insect biomass. However, it should be noted that larvae resulting from the apple diet contained 50% more fat than larvae fed the fruit and spent grain mixtures. Commonly-available organic wastes were successfully used at an industrial scale to produce BSF larvae that have the potential to substitute other sources of protein and lipids in different industrial applications. Industrialization efforts are encouraged to assess these impacts when integrating diverse ingredients into larval diets as a means to more precisely predict output, such as larval development time and final larval biomass.
Antibiotics are essential drugs used to treat pathogenic bacteria, but their prolonged use contributes to the development and spread of drug-resistant microorganisms. Antibiotic resistance is a ...serious challenge and has led to the need for new alternative molecules less prone to bacterial resistance. Antimicrobial peptides (AMPs) have aroused great interest as potential next-generation antibiotics, since they are bioactive small proteins, naturally produced by all living organisms, and representing the first line of defense against fungi, viruses and bacteria. AMPs are commonly classified according to their sources, which are represented by microorganisms, plants and animals, as well as to their secondary structure, their biosynthesis and their mechanism of action. They find application in different fields such as agriculture, food industry and medicine, on which we focused our attention in this review. Particularly, we examined AMP potential applicability in wound healing, skin infections and metabolic syndrome, considering their ability to act as potential Angiotensin-Converting Enzyme I and pancreatic lipase inhibitory peptides as well as antioxidant peptides. Moreover, we argued about the pharmacokinetic and pharmacodynamic approaches to develop new antibiotics, the drug development strategies and the formulation approaches which need to be taken into account in developing clinically suitable AMP applications.
During oviposition, ectoparasitoid wasps not only inject their eggs but also a complex mixture of proteins and peptides (venom) in order to regulate the host physiology to benefit their progeny. ...Although several endoparasitoid venom proteins have been identified, little is known about the components of ectoparasitoid venom. To characterize the protein composition of Torymus sinensis Kamijo (Hymenoptera: Torymidae) venom, we used an integrated transcriptomic and proteomic approach and identified 143 venom proteins. Moreover, focusing on venom gland transcriptome, we selected additional 52 transcripts encoding putative venom proteins. As in other parasitoid venoms, hydrolases, including proteases, phosphatases, esterases, and nucleases, constitute the most abundant families in T. sinensis venom, followed by protease inhibitors. These proteins are potentially involved in the complex parasitic syndrome, with different effects on the immune system, physiological processes and development of the host, and contribute to provide nutrients to the parasitoid progeny. Although additional in vivo studies are needed, initial findings offer important information about venom factors and their putative host effects, which are essential to ensure the success of parasitism.
Between the 1970s and the 1990s, cities in Southern Europe experienced a progressive delocalisation of population, settlements and activities over larger regions. Economic downturns have increasingly ...influenced more recent waves of metropolitan growth, shaping differentiated patterns of urban change. While some cities evolved towards accelerated population dynamics in central districts responding to re-urbanisation impulses, other agglomerations were intrinsically bounded in a sort of ‘late suburbanisation’, with demographic shrinkage of both inner districts and rural areas, and uneven expansion of suburban population. By providing a comprehensive interpretation of the socioeconomic mechanisms underlying recent urban expansion, this study illustrates a diachronic analysis of population dynamics over multiple spatial scales and time frames in a metropolitan region of Southern Europe (Athens, Greece) between 1999 and 2019. Natural population balance was investigated vis à vis selected territorial indicators using descriptive, inferential and multivariate statistics. Results of the analysis identify different social forces underlying suburban population growth during economic expansion (2000s) and recession (2010s), evidencing a distinctive response of local communities to economic downturns that depends mostly on the background context (affluent versus disadvantaged neighbourhoods). Given the multiplicity of territorial dimensions involved in urban growth, our findings highlight how economic downturns distinctively shape metropolitan development based on locally differentiated demographic dynamics.
Insects, the most varied group of known organisms on Earth, are arousing great interest also for the possibility to use them as a feed and food source. The mass rearing of some species, defined as ..."bioconverters", is spreading worldwide, thanks to their sustainability. At the end of the bioconversion process, breeders obtain eco-friendly biomolecules of high biological and economic value, including proteins and lipids, from larvae of bioconverter insects, in particular
. Besides the most classical use of insect lipids as food additives, they are also used in the formulation of several products for personal care. The composition of insect lipids depends on the substrate on which the insects are reared but also on the insect species, so the cosmetic producers should consider these features to choose their insect starting point. The most abundant fatty acids detected in
are lauric, myristic, palmitic, and oleic acids, regardless of feed substrate; its fatty acids composition is favorable for soap composition, while their derivatives are used for detergent and shampoo. Here, we offer an overview of insect lipids, their extraction methods, and their application in cosmetics and personal care products.
•This study evaluates statistical robustness of 6 indicators of land degradation.•Indicators’ stability was tested at six spatial scale simulating different planning levels.•Statistical analysis ...identified two non-redundant dimensions of land degradation.•Average sensitivity and ESAI coefficient of variation are non-redundant indicators.•Multi-scale analysis provides appropriate insights into ecological-economic processes.
This work provides a multi-scale, multi-temporal assessment of the robustness of 6 indicators of land degradation aggregated at various spatial domains relevant to environmental reporting. Based on the Environmentally Sensitive Area (ESA) approach – widely used for environmental reporting of land degradation in Europe – we tested six indicators including (i) the average ESA score, (ii) the maximum ESA score, (iii) the coefficient of variation in the ESA scores, (iv) the normalized range in the ESA scores, as well as the extent of (v) ‘fragile’ and (vi) ‘critical’ areas based on a standard land classification developed on behalf of the ESA framework. Statistical robustness and intrinsic stability of these indicators were verified at six spatial domains (administrative regions, provinces, elevation belts, homogeneous economic districts, rural districts, municipalities) separately for three time points (early-1960s, early-1990s, and early-2010s). Results of a mixed parametric/non-parametric correlation analysis indicate that pair-wise relationships between indicators were mostly linear. A Principal Component Analysis identified two non-redundant dimensions associated with the average level of land degradation sensitivity and its intrinsic variability over space; indicators resulted to be associated exclusively with one of these two dimensions for all study years. Average level of sensitivity and variability over space provide, together, a comprehensive and statistically robust assessment of land degradation at vastly different planning levels, irrespective of the territorial domain adopted for environmental reporting.
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