Chitin

In this work we have characterized and compared chitin sourced from exoskeleton of Tenebrio molitor larvae fed with polystyrene or plastic kitchen wrap combined with bran in the ratio 1: 1 with chitin sourced from larvae exoskeleton fed only with bran. Analysis of the frass by ATR-FTIR showed very similar spectra and confirmed degradation of the plastic feed components, while ATR-FTIR analysis of the exoskeleton verified the absence of any plastic residue. Deproteinization followed by demineralization produced 6...

Thermophilic endo-chitinases are essential for production of highly polymerized chitooligosaccharides, which are advantageous for plant immunity, animal nutrition and health. However, thermophilic endo-chitinases are scarce and the transformation from exo- to endo-activity of chitinases is still a challenging problem. In this study, to enhance the endo-activity of the thermophilic chitinase Chi304, we proposed two approaches for rational design based on comprehensive structural and evolutionary analyses. Four effective single-point mutants were identified among 28 designed mutations...

Fomes fomentarius is a widespread, wood-rotting fungus of temperate, broadleaved forests. Although the fruiting bodies of F. fomentarius persist for multiple years, little is known about its associated microbiome or how these recalcitrant structures are ultimately decomposed. Here we used metagenomics and metatranscriptomics to analyse the microbial community associated with healthy living and decomposing F. fomentarius fruiting bodies to assess the functional potential of the fruiting body-associated microbiome and to determine the main players involved in fruiting body decomposition...

Biological nanofibrils not only are characteristic of many species of biomasses but also serve as a promising type of sustainable nanomaterials for various applications. However, their production has long relied on an invasive and energy-consuming mechanical shear. A noninvasive and versatile approach remains challenging to exfoliate different types of biomasses into nanofibrils. In this study, we showed a versatile and nonaggressive intercalative deprotonation agent of organic base, which could efficiently deprotonate various biomasses for energy-saving exfoliation and functionalization, including cellulose, chitin, and silk...

Ctenostomes are a group of gymnolaemate bryozoans with an uncalcified chitinous body wall having few external, skeletal characters. Hence, species identification is challenging and their systematics remain poorly understood, even more so when they exhibit an endolithic (boring) lifestyle. Currently, there are four Recent families of endolithic bryozoans that live inside mineralized substrates like mollusk shells. In particular, Penetrantiidae Silén, 1946 has received considerable attention and its systematic affinity to either cheilostomes or ctenostomes has been debated...

Macins are a family of antimicrobial peptides, which play multiple roles in the elimination of invading pathogens. In the present study, a macin was cloned and characterized from Pacific abalone Haliotis discus hannai (Designated as HdMac). Analysis of the conserved domain suggested that HdMac was a new member of the macin family. In non-stimulated abalones, HdMac transcripts were constitutively expressed in all five tested tissues, especially in hemocytes. After Vibrio harveyi stimulation, the expression of HdMac mRNA in hemocytes was significantly up-regulated at 12 hr (P < 0...

Extracellular proteases, such as chitinases secreted by Arthrobotrys oligospora (A. oligospora), play a crucial role in the process of nematode infection. However, post-transcriptional regulation of gene expression involving microRNAs (miRNAs) in A. oligospora remains scarcely described. Hereto, transcriptome sequencing was carried out to analyze the expression profiles of chitin-responsive miRNAs in A. oligospora. Based on the RNA-seq data, the differential expression of miRNAs (DEmiRNAs) in response to chitin was screened, identified and characterized in A...

Ubiquitination-mediated protein degradation is integral to plant immunity, with E3 ubiquitin ligases acting as key factors in this process. Here, we report the functions of OsATL32, a plasma membrane-localized Arabidopsis Tóxicos En Levadura (ATL)-type E3 ubiquitin ligase, in rice (Oryza sativa) immunity and its associated regulatory network. We found that the expression of OsATL32 is downregulated in both compatible and incompatible interactions between rice and the rice blast fungus Magnaporthe oryzae...

The majority of bioactive polysaccharides are present in some marine creatures. These polysaccharides are considered as promising anti-obesity agents, their anti-obesity properties involve a number of mechanisms, including suppression of lipid metabolism and absorption, impact on satiety, and prevention of adipocyte differentiation. Obesity is linked to type 2 diabetes, cardiovascular disease, and other metabolic syndromes. In this review various bioactive polysaccharides like chitin, chitosan, fucosylated chondroitin sulphate, chitooligosaccharides and glycosaminoglycans have been discussed for their anti-obesity effects through various pathways...

N-acetylglucosamine (GlcNAc) is an important structural component of the cell wall chitin, N-glycans, glycolipids, and GPI-anchors in eukaryotes. GlcNAc kinase phosphorylates GlcNAc into GlcNAc-6-phosphate, a precursor of uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) that serves as a substrate for glycan synthesis. Although GlcNAc kinase is found widely in organisms ranging from microorganisms to mammals, it has never been found in the model yeast Saccharomyces cerevisiae. Here, we demonstrate the presence of GlcNAc metabolism for UDP-GlcNAc biosynthesis in S...

Toxocara cati and T. canis are parasitic nematodes found in the intestines of cats and dogs respectively, with a cosmopolitan distribution, and the potential for anthropozoonotic transmission, resulting in human toxocariasis. Spread of Toxocara spp. is primarily through the ingestion of embryonated eggs contaminating surfaces or uncooked food, or through the ingestion of a paratenic host containing a third-stage larva. The Toxocara spp. eggshell is composed of a lipid layer providing a permeability barrier, a chitinous layer providing structural strength, and thin vitelline and uterine layers, which combined create a biologically resistant structure, making the Toxocara spp...

The crustacean cuticle is a biological composite material consisting of chitin-protein fibres in a mineralized matrix. Recent research has revealed a surprising range of fibre architectures and mineral compositions of crustacean skeletal structures adapted to various mechanical demands. It is becoming increasingly clear that the organic fibres in the cuticle may be organized in patterns differing from the standard twisted plywood model. Observed fibre architectures in protruding skeletal structures include longitudinal and circular parallel fibre arrays...

Cuttlefish bone biowaste is a potential source of a composite matrix based on chitin and aragonite. In the present work, we propose for the first time the elaboration of biocomposites based on chitosan and aragonite through the valorization of bone waste. The composition of the ventral and dorsal surfaces of bone is well studied by ICP-OES. An extraction process has been applied to the dorsal surface to extract β-chitin and chitosan with controlled physico-chemical characteristics. In parallel, aragonite isolation was carried out on the ventral side...

A novel β-galactosidase (TsGal48) from Thermus scotoductus was cloned, and the enzyme was biochemically characterized. TsGal48 catalyzed the synthesis of lacto- N -neotetraose (LNnT) from lactose via the transglycosylation reaction with a maximal yield of 20%, which is the highest yield for the synthesis of LNnT so far. To further improve the yield of LNnT, TsGal48 was successfully engineered by directed evolution and site-saturation mutagenesis. A mutated β-galactosidase (mTsGal48) was selected and characterized...

Unsaturated fatty acids present in fish oil offer various physiological benefits to the human body. However, their susceptibility to oxidation severely limits their potential applications. The purpose of this study was to develop Pickering emulsions stabilized from a composite of resveratrol-loaded gliadin nanoparticles and oxidized chitin nanocrystals (GR/OC) to protect fish oil from oxidation. The effects of the GR/OC composite on the characterizations of fish oil Pickering emulsions were investigated, including the microstructure, physicochemical properties (stability and rheological behavior), and digestion properties in vitro...

Candida albicans is a prevalent fungal pathogen that displays antibiotic resistance. The polyene antifungal amphotericin B (AmB) has been the gold standard because of its broad antifungal spectra, and its liposomal formulation, AmBisome, has been used widely and clinically in treating fungal infections. Herein, we explored enhancing the antifungal activity of AmBisome by integrating a small chitin-binding domain (LysM) of chitinase A derived from Pteris ryukyuensis . LysM conjugated with a lipid (LysM-lipid) was initially prepared through microbial transglutaminase (MTG)-mediated peptide tag-specific conjugation of LysM with a lipid-peptide substrate...

Spodoptera frugiperda , the fall armyworm (FAW), is a highly invasive polyphagous insect pest that is considered a source of severe economic losses to agricultural production. Currently, the majority of chemical insecticides pose tremendous threats to humans and animals besides insect resistance. Thus, there is an urgent need to develop new pest management strategies with more specificity, efficiency, and sustainability. Chitin-degrading enzymes, including chitinases, are promising agents which may contribute to FAW control...

Chitosan is a derivative of chitin that is one of the most abundant biopolymers in nature, found in crustacean shells as well as in fungi cell walls. Most of the commercially available chitosans are produced from the exoskeletons of crustaceans. The extraction process involves harsh chemicals, has limited potential due to the seasonal and limited supply and could cause allergic reactions. However, chitosan has been shown to alleviate the negative effect of environmental stressors in plants, but there is sparse evidence of how chitosan source affects this bioactivity...

Chitin and chitosan are important structural macromolecules for most fungi and marine crustaceans. The functions and application areas of the two molecules are also adjacent beyond their similar molecular structure, such as tissue engineering and food safety where solution systems are involved. However, the elasticities of chitin and chitosan in solution lack comparison at the molecular level. In this study, the single-molecule elasticities of chitin and chitosan in different solutions are investigated via atomic force microscope (AFM) based single-molecule spectroscopy (SMFS)...

Semi-crystalline natural polymers are involved in many technological processes. Biopolymers having identical chemical compositions can differ in reactivity in heterogeneous transformations depending on their crystal structure (polymorphic modification). This paper compares the crystal structure recrystallization processes occurring in natural polysaccharides (cellulose, chitin, and starch) in the individual form and as a component of native biomass. Aqueous treatment of pre-amorphized semi-crystalline biopolymers was shown to result in swelling, thus alleviating the kinetic restrictions imposed on the restoration of crystalline regions and phase transition to the thermodynamically more stable polymorphic modification...