Plasma-Activated Water Boosts the Activity of Lytic Polysaccharide Monooxygenase and the Conversion of Chitin by a Chitinolytic Enzyme Cocktail.

The plasma-activated water (PAW) containing numerous reactive species can facilitate chitin degradation. Given the intricate interplay between PAW treatment and the diverse activities of chitinolytic enzymes, further investigation is imperative for enhancing the chitin bioconversion efficiency. This study revealed that PAW-treated chitin exhibited improved degradability toward LPMO10A, endochitinases ChtI, ChtII-B4C1, and exochitinase Chi-h.

High-speed atomic force microscopy reveals opposite traffic of processive chitinases impairs α-chitin biodegradation.

The antiparallelly organized α-chitin exhibits greater thermodynamic stability and is more recalcitrant to degradation than its parallel allomorph, β-chitin, thereby impeding the efficient utilization of this natural resource. The processive chitinases usually provide the majority of catalytic potential for chitin biodegradation. Using high-speed atomic force microscopy (HS-AFM), we revealed that the opposite traffic of OfChi-h, the only processive chitinase involved in chitin biodegradation in the insect Ostrinia furnacalis, is a key factor that significantly affects α-chitin degradation.

Tissue-specific alternative splicing and the functional differentiation of LmLPMO15-1 in Locusta migratoria.

Insect lytic polysaccharide monooxygenases (LPMO15s) are newly discovered copper-dependent enzymes that promote chitin degradation in insect through oxidative cleavage of glycosidic bonds. They are potential pesticide targets due to their critical role for chitin turnover in the integument, trachea, and peritrophic matrix of the midgut during insect molting. However, the knowledge about whether and how LPMO15s participate in chitin turnover in other tissues is still insufficient.

Biochemical Properties of a Novel Cold-Adapted GH19 Chitinase with Three Chitin-Binding Domains from CSC-1 and Its Potential in Biocontrol of Plant Pathogenic Fungi.

GH19 (glycoside hydrolase 19) chitinases play crucial roles in the enzymatic conversion of chitin and biocontrol of phytopathogenic fungi. Herein, a novel multifunctional chitinase of GH19 (Chi19A), which contains three chitin-binding domains (ChBDs), was successfully cloned from CSC-1 and heterologously expressed in . We also generated truncated mutants of Chi19A_ΔI, Chi19A_ΔIΔII, and Chi19A_CatD consisting of two ChBDs and a catalytic domain, one ChBD and a catalytic domain, and only a catalytic domain, respectively.

Functional role of carbohydrate-binding modules in multi-modular chitinase OfChtII.

The primary distinction between insect and bacterial chitin degradation systems lies in the presence of a multi-modular endo-acting chitinase ChtII, in contrast to a processive exo-acting chitinase. Although the essential role of ChtII during insect development and its synergistic action with processive chitinase during chitin degradation has been established, the mechanistic understanding of how it deconstructs chitin remains largely elusive. Here OfChtII from the insect Ostrinia furnacalis was investigated employing comprehensive approaches encompassing biochemical and microscopic analyses.

Alternative relay regulates the adenosine triphosphatase activity of Locusta migratoria striated muscle myosin.

Locust (Locusta migratoria) has a single striated muscle myosin heavy chain (Mhc) gene, which contains 5 clusters of alternative exclusive exons and 1 differently included penultimate exon. The alternative exons of Mhc gene encode 4 distinct regions in the myosin motor domain, that is, the N-terminal SH3-like domain, one lip of the nucleotide-binding pocket, the relay, and the converter. Here, we investigated the role of the alternative regions on the motor function of locust muscle myosin.

Group h Chitinase: A Molecular Target for the Development of Lepidopteran-Specific Insecticides.

Sustainable agriculture requires insecticides that are selective between insects and mammals and even between harmful and beneficial insects. Lepidoptera includes the largest number of insect pests that threaten crops, and Hymenoptera contains the natural enemies for these pests. Discovery of lepidopteran-specific molecular targets is one route to develop such selective pesticides.

AA15 lytic polysaccharide monooxygenase is required for efficient chitinous cuticle turnover during insect molting.

Microbial lytic polysaccharide monooxygenases (LPMOs) catalyze the oxidative cleavage of crystalline polysaccharides including chitin and cellulose. The discovery of a large assortment of LPMO-like proteins widely distributed in insect genomes suggests that they could be involved in assisting chitin degradation in the exoskeleton, tracheae and peritrophic matrix during development. However, the physiological functions of insect LPMO-like proteins are still undetermined.

A midgut-specific lytic polysaccharide monooxygenase of Locusta migratoria is indispensable for the deconstruction of the peritrophic matrix.

Lytic polysaccharide monooxygenases (LPMOs) are important enzymes that boost the hydrolysis of recalcitrant polysaccharides, such as chitin. They are found extensively in different insect species and are classified as auxiliary activities family 15 (AA15) LPMOs (LPMO15). Some of them were identified from the insect midgut and proven to act on chitin.

Phylogenetic relationships and biological features reveal that male Ostrinia furnacalis (Lepidoptera: Crambidae) in Northeast China can be categorized into postmedial line-based clades.

Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae), often called the Asian corn borer, is a complicated pest because of its complex biological features, such as its adult dynamics, host choice, and life span. This complexity has been causing difficulties in both pest forecasting and control for more than 60 years. One likely explanation for this complexity is that O.

Insect group II chitinase OfChtII promotes chitin degradation during larva-pupa molting.

The insect group II chitinase (ChtII, also known as Cht10) is a unique chitinase with multiple catalytic and chitin-binding domains. It has been proven genetically to be an essential chitinase for molting. However, ChtII's role in chitin degradation during insect development remains poorly understood.

Structural and biochemical insights into the catalytic mechanisms of two insect chitin deacetylases of the carbohydrate esterase 4 family.

Insect chitin deacetylases (CDAs) catalyze the removal of acetyl groups from chitin and modify this polymer during its synthesis and reorganization. CDAs are essential for insect survival and therefore represent promising targets for insecticide development. However, the structural and biochemical characteristics of insect CDAs have remained elusive.

Biochemical characterization of three midgut chitin deacetylases of the Lepidopteran insect Bombyx mori.

Peritrophic membrane (PM) is a chitin and protein-containing extracellular matrix that lines the midgut in most insect species, functioning as a barrier to exogenous toxins and pathogens. Midgut chitin deacetylases (CDAs) are chitin-modifying enzymes known to alter the mechanical property and permeability of PM. However, biochemical properties and specific roles of these enzymes remain elusive.

The deduced role of a chitinase containing two nonsynergistic catalytic domains.

The glycoside hydrolase family 18 chitinases degrade or alter chitin. Multiple catalytic domains in a glycoside hydrolase family 18 chitinase function synergistically during chitin degradation. Here, an insect group III chitinase from the agricultural pest Ostrinia furnacalis (OfChtIII) is revealed to be an arthropod-conserved chitinase that contains two nonsynergistic GH18 domains according to its catalytic properties.

Structural analysis of group II chitinase (ChtII) catalysis completes the puzzle of chitin hydrolysis in insects.

Chitin is a linear homopolymer of -acetyl-β-d-glucosamines and a major structural component of insect cuticles. Chitin hydrolysis involves glycoside hydrolase family 18 (GH18) chitinases. In insects, chitin hydrolysis is essential for periodic shedding of the old cuticle ecdysis and proceeds via a pathway different from that in the well studied bacterial chitinolytic system.

Fully deacetylated chitooligosaccharides act as efficient glycoside hydrolase family 18 chitinase inhibitors.

Small molecule inhibitors against chitinases have potential applications as pesticides, fungicides, and antiasthmatics. Here, we report that a series of fully deacetylated chitooligosaccharides (GlcN)2-7 can act as inhibitors against the insect chitinase OfChtI, the human chitinase HsCht, and the bacterial chitinases SmChiA and SmChiB with IC50 values at micromolar to millimolar levels. The injection of mixed (GlcN)2-7 into the fifth instar larvae of the insect Ostrinia furnacalis resulted in 85% of the larvae being arrested at the larval stage and death after 10 days, also suggesting that (GlcN)2-7 might inhibit OfChtI in vivo.

Proteomic analysis of insect molting fluid with a focus on enzymes involved in chitin degradation.

Cuticular chitin degradation is extremely important for insect growth and development, which has not been fully understood thus far. One obstacle to understanding this mechanism is the lack of a systematic analysis of the chitinolytic enzymes involved in cuticular chitin degradation. In this study, we used the silkmoth Bombyx mori as a model organism and compared proteomic analyses for larval-pupal (L-P) and pupal-adult (P-A) molting fluids using tandem mass tag quantitative mass spectrometry.

A sperm-plasma β-N-acetyl-D-hexosaminidase interacting with a Chitinolytic β-N-Acetyl-D-hexosaminidase in insect molting fluid.

Insects require molting fluids to shed the old cuticle during molting. β-N-acetyl-D-hexosaminidase, known as Hex1, together with various chitinases, is responsible for degrading the chitin component of the old cuticle. This study showed that another β-N-acetyl-D-hexosaminidase, termed OfHex3, interacted with Hex1 and functioned in the molting fluid, although the homolog of OfHex3 was known as a sperm-plasma enzyme functioning in egg-sperm recognition.

Biochemical characterization of a novel β-N-acetylhexosaminidase from the insect Ostrinia furnacalis.

The β-N-acetylhexosaminidase FDL specifically removes the β-1,2-GlcNAc residue conjugated to the α-1,3-mannose residue of the core structure of insect N-glycans, playing significant physiological roles in post-translational modification in the Golgi apparatus. Little is known about its enzymatic properties. We obtained the OfFDL gene from the insect Ostrinia furnacalis by RT-PCR.

Molecular and biochemical characterization of a novel β-N-acetyl-D-hexosaminidase with broad substrate-spectrum from the Aisan corn borer, Ostrinia furnacalis.

Insect β-N-acetyl-D-hexosaminidases with broad substrate-spectrum (IBS-Hex) are the homologues of human β-N-acetyl-D-hexosaminidase A/B (HsHex A/ B). These enzymes are distributed in most insect species and vary in physiological roles. In this study, the gene encoding an IBS-Hex, OfHEX2, was cloned from the Asian corn borer, Ostrinia furnacalis.

A novel alternative splicing site of class A chitin synthase from the insect Ostrinia furnacalis - gene organization, expression pattern and physiological significance.

Insect chitin synthase A (CHSA) catalyzes chitin biosynthesis in tissues that develop from ectoderm. Since only one gene copy encodes CHSA, we hypothesized that CHSA is very likely to exist as isoforms through alternative splicing, and the functions of these isoforms may be tissue-specific. Besides the known alternative splicing exons in the mid-ORF region, we report here the alternative exons (OfCHSA-2a and OfCHSA-2b) of OfCHSA, the chitin synthase A from the lepidopteran pest Ostrinia furnacalis.

The gene, expression pattern and subcellular localization of chitin synthase B from the insect Ostrinia furnacalis.

Insect midgut peritrophic membrane (PM) is a functional structure that protects insects against chemical damage and microorganism infection. The essential component in PM is chitin and its synthesis is catalyzed by Class B chitin synthase (CHSB), which plays a unique role in chitin-containing organisms and thus represents a potential target for eco-friendly pesticides. cDNA and gDNA of CHSB from a widely spread pest Ostrinia furnacalis (OfCHSB) were obtained and their sequences and transcription patterns were characterized.

A novel beta-N-acetyl-D-hexosaminidase from the insect Ostrinia furnacalis (Guenée).

Exploiting specific targets is of specific interest in developing eco-friendly pesticides. We isolated, purified and characterized a novel beta-N-acetyl-D-hexosaminidase (OfHex1) from the fifth instar larva integument of the Asian corn borer, Ostrinia furnacalis (Guenée). OfHex1 was purified 1468-fold to homogeneity with an activity yield of 20% by four column chromatography steps.