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1.
PLoS One ; 19(6): e0304614, 2024.
Article in English | MEDLINE | ID: mdl-38870218

ABSTRACT

Humanity is often fascinated by structures and materials developed by Nature. While structural materials such as wood have been widely studied, the structural and mechanical properties of fungi are still largely unknown. One of the structurally interesting fungi is the polypore Fomes fomentarius. The present study deals with the investigation of the light but robust fruiting body of F. fomentarius. The four segments of the fruiting body (crust, trama, hymenium, and mycelial core) were examined. The comprehensive analysis included structural, chemical, and mechanical characterization with particular attention to cell wall composition, such as chitin/chitosan and glucan content, degree of deacetylation, and distribution of trace elements. The hymenium exhibited the best mechanical properties even though having the highest porosity. Our results suggest that this outstanding strength is due to the high proportion of skeletal hyphae and the highest chitin/chitosan content in the cell wall, next to its honeycomb structure. In addition, an increased calcium content was found in the hymenium and crust, and the presence of calcium oxalate crystals was confirmed by SEM-EDX. Interestingly, layers with different densities as well as layers of varying calcium and potassium depletion were found in the crust. Our results show the importance of considering the different structural and compositional characteristics of the segments when developing fungal-inspired materials and products. Moreover, the porous yet robust structure of hymenium is a promising blueprint for the development of advanced smart materials.


Subject(s)
Fruiting Bodies, Fungal , Fruiting Bodies, Fungal/chemistry , Chitin/chemistry , Chitin/metabolism , Cell Wall/chemistry , Coriolaceae/metabolism , Coriolaceae/chemistry , Chitosan/chemistry , Compressive Strength , Glucans/chemistry , Glucans/metabolism , Porosity
2.
Int J Biol Macromol ; 272(Pt 1): 132799, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38830496

ABSTRACT

Peritrophic membrane (PM) is a pellicle structure present in the midgut of some invertebrates, such as insects and crustaceans. It could isolate harmful components and pathogens in food from intestinal epithelial cells; and it also plays a role in improving digestion and absorption efficiency. So PM is important for survival of its owner. In current study, 44 PM proteins were identified in Litopenaeus vannamei by PM proteome analysis. Among these PM proteins, the Peritrophin-44 homologous protein (LvPT44) was further studied. Chitin-binding assay indicated that LvPT44 could bind to colloidal chitin, and immunoeletron microscopy analysis shown that it was located to PM of L. vannamei. Furthermore, LvPT44 promoter was found to be activated by L. vannamei STAT and c-Jun. Besides, LvPT44 was induced by ER-stress as well as white spot syndrome virus infection. Knocked-down expression of LvPT44 by RNA inference increased the cumulative mortality of shrimp that caused by ER-stress or white spot syndrome virus. These results suggested that LvPT44 has an important role in disease resistance.


Subject(s)
Disease Resistance , Penaeidae , White spot syndrome virus 1 , Animals , Penaeidae/genetics , Penaeidae/virology , Penaeidae/metabolism , Disease Resistance/genetics , White spot syndrome virus 1/genetics , Arthropod Proteins/genetics , Arthropod Proteins/metabolism , Chitin/metabolism , Promoter Regions, Genetic/genetics , Gene Expression Regulation
3.
Carbohydr Res ; 541: 109170, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38830279

ABSTRACT

The development of chitinase tailored for the bioconversion of chitin to chitin oligosaccharides has attracted significant attention due to its potential to alleviate environmental pollution associated with chemical conversion processes. In this present investigation, we purified extracellular chitinase derived from marine Bacillus haynesii to homogeneity and subsequently characterized it. The molecular weight of BhChi was approximately 35 kDa. BhChi displayed its peak catalytic activity at pH 6.0, with an optimal temperature of 37 °C. It exhibited stability across a pH range of 6.0-9.0. In addition, BhChi showed activation in the presence of Mn2+ with the improved activity of 105 U mL-1. Ca2+ and Fe2+ metal ions did not have any significant impact on enzyme activity. Under the optimized enzymatic conditions, there was a notable enhancement in catalytic activity on colloidal chitin with Km of 0.01 mg mL-1 and Vmax of 5.75 mmol min-1. Kcat and catalytic efficiency were measured at 1.91 s-1 and 191 mL mg-1 s-1, respectively. The product profiling of BhChi using thin layer chromatography and Mass spectrometric techniques hinted an exochitinase mode of action with chitobiose and N-Acetyl glucosamine as the products. This study represents the first report on an exochitinase from Bacillus haynesii. Furthermore, the chitinase showcased promising antifungal properties against key pathogens, Fusarium oxysporum and Penicillium chrysogenum, reinforcing its potential as a potent biocontrol agent.


Subject(s)
Antifungal Agents , Bacillus , Chitin , Chitinases , Chitinases/metabolism , Chitinases/isolation & purification , Chitinases/chemistry , Chitinases/pharmacology , Chitin/chemistry , Chitin/metabolism , Chitin/pharmacology , Antifungal Agents/pharmacology , Antifungal Agents/chemistry , Antifungal Agents/isolation & purification , Antifungal Agents/metabolism , Bacillus/enzymology , Fusarium/enzymology , Fusarium/drug effects , Hydrogen-Ion Concentration , Temperature
4.
Pestic Biochem Physiol ; 202: 105962, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38879310

ABSTRACT

Lufenuron, a benzoylurea chitin synthesis inhibitor, is effective against many insect pests. However, the insecticidal activity of lufenuron has not been completely elucidated, nor has its disturbing effect on chitin synthesis genes. In this study, bioassay results demonstrated an outstanding toxicity of lufenuron against Helicoverpa armigera larvae. The treated larvae died from abortive molting and metamorphosis defects, and severe separation of epidermis and subcutaneous tissues was observed. Treatment of 3rd- and 4th-instar larvae with LC25 lufenuron significantly extended the duration of larval and pupal stage, reduced the rates of pupation and emergence, and adversely affected pupal weight. Besides, lufenuron can severely reduce chitin content in larval integument, and the lufenuron-treated larvae showed reduced trehalose content in their hemolymph. Further analysis using RNA sequencing revealed that five chitin synthesis genes were down-regulated, whereas the expressions of two chitin degradation genes were significantly enhanced. Knockdown of chitin synthase 1 (HaCHS1), uridine diphosphate-N-acetylglucosamine-pyrophosphorylase (HaUAP), phosphoacetyl glucosamine mutase (HaPGM), and glucosamine 6-phosphate N-acetyl-transferase (HaGNPAT) in H. armigera led to significant increase in larval susceptibilities to LC25 lufenuron by 75.48%, 65.00%, 68.42% and 28.00%, respectively. Our findings therefore revealed the adverse effects of sublethal doses of lufenuron on the development of H. armigera larvae, elucidated the perturbations on chitin metabolism, and proved that the combination of RNAi and lufenuron would improve the control effect of this pest.


Subject(s)
Benzamides , Chitin , Insecticides , Larva , Moths , Animals , Chitin/biosynthesis , Benzamides/pharmacology , Larva/drug effects , Insecticides/pharmacology , Insecticides/toxicity , Moths/drug effects , Moths/metabolism , Moths/growth & development , Insect Proteins/metabolism , Insect Proteins/genetics , Chitin Synthase/metabolism , Chitin Synthase/genetics , Helicoverpa armigera , Fluorocarbons
5.
Biomacromolecules ; 25(6): 3449-3463, 2024 Jun 10.
Article in English | MEDLINE | ID: mdl-38739908

ABSTRACT

Using supramolecular self-assembled nanocomposite materials made from protein and polysaccharide components is becoming more popular because of their unique properties, such as biodegradability, hierarchical structures, and tunable multifunctionality. However, the fabrication of these materials in a reproducible way remains a challenge. This study presents a new evaporation-induced self-assembly method producing layered hydrogel membranes (LHMs) using tropocollagen grafted by partially deacetylated chitin nanocrystals (CO-g-ChNCs). ChNCs help stabilize tropocollagen's helical conformation and fibrillar structure by forming a hierarchical microstructure through chemical and physical interactions. The LHMs show improved mechanical properties, cytocompatibility, and the ability to control drug release using octenidine dihydrochloride (OCT) as a drug model. Because of the high synergetic performance between CO and ChNCs, the modulus, strength, and toughness increased significantly compared to native CO. The biocompatibility of LHM was tested using the normal human dermal fibroblast (NHDF) and the human osteosarcoma cell line (Saos-2). Cytocompatibility and cell adhesion improved with the introduction of ChNCs. The extracted ChNCs are used as a reinforcing nanofiller to enhance the performance properties of tropocollagen hydrogel membranes and provide new insights into the design of novel LHMs that could be used for various medical applications, such as control of drug release in the skin and bone tissue regeneration.


Subject(s)
Hydrogels , Humans , Hydrogels/chemistry , Hydrogels/pharmacology , Nanoparticles/chemistry , Chitin/chemistry , Cell Line, Tumor , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology , Fibroblasts/drug effects , Fibroblasts/cytology , Membranes, Artificial , Nanocomposites/chemistry , Cell Adhesion/drug effects
7.
Cell Rep Med ; 5(5): 101560, 2024 May 21.
Article in English | MEDLINE | ID: mdl-38729159

ABSTRACT

Stimulator of IFN genes (STING) is a promising target for adjuvants utilized in in situ cancer vaccination approaches. However, key barriers remain for clinical translation, including low cellular uptake and accessibility, STING variability necessitating personalized STING agonists, and interferon (IFN)-independent signals that can promote tumor growth. Here, we identify C100, a highly deacetylated chitin-derived polymer (HDCP), as an attractive alternative to conventional STING agonists. C100 promotes potent anti-tumor immune responses, outperforming less deacetylated HDCPs, with therapeutic efficacy dependent on STING and IFN alpha/beta receptor (IFNAR) signaling and CD8+ T cell mediators. Additionally, C100 injection synergizes with systemic checkpoint blockade targeting PD-1. Mechanistically, C100 triggers mitochondrial stress and DNA damage to exclusively activate the IFN arm of the cGAS-STING signaling pathway and elicit sustained IFNAR signaling. Altogether, these results reveal an effective STING- and IFNAR-dependent adjuvant for in situ cancer vaccines with a defined mechanism and distinct properties that overcome common limitations of existing STING therapeutics.


Subject(s)
Adjuvants, Immunologic , CD8-Positive T-Lymphocytes , Chitin , Membrane Proteins , Mice, Inbred C57BL , Receptor, Interferon alpha-beta , Signal Transduction , Animals , Membrane Proteins/metabolism , Membrane Proteins/immunology , Membrane Proteins/genetics , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , Receptor, Interferon alpha-beta/metabolism , Receptor, Interferon alpha-beta/genetics , Mice , Adjuvants, Immunologic/pharmacology , Adjuvants, Immunologic/administration & dosage , Signal Transduction/drug effects , Humans , Cancer Vaccines/immunology , Cancer Vaccines/administration & dosage , Cell Line, Tumor , Female , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/genetics , Programmed Cell Death 1 Receptor/metabolism , Programmed Cell Death 1 Receptor/immunology , Neoplasms/immunology , Neoplasms/therapy
8.
Int J Biol Macromol ; 270(Pt 2): 132283, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38735605

ABSTRACT

A new conjugate, galloyl-oligochitosan nanoparticles (GOCNPs), was fabricated and used as nano-vehicle for effective and controlled delivery of propolis extract (PE) in the form of PE#GOCNPs, targeting improving its pharmaceutical potential. H-bonding interactions between the carboxyl, amino, and hydroxyl groups of the GOCNPs and PE resulted in successful encapsulation, with an entrapment efficacy of 97.3 %. The PE#GOCNPs formulation also exhibited excellent physicochemical stability and time-triggered drug release characteristics under physiological conditions. Furthermore, PE#GOCNPs showed significant activity against MCF-7 and HEPG2 carcinoma cells by scavenging free oxygen radicals and upregulating antioxidant enzymes. Additionally, PE#GOCNPs displayed anti-inflammatory properties by increasing IL10 and reducing pro-inflammatory cytokines more effectively than celecoxib. Furthermore, PE#GOCNPs reduced the expression of epidermal growth factor receptor (EGFR) and survivin genes. Furthermore, the encapsulated PE demonstrated significant activity in suppressing sonic hedgehog protein (SHH). The use of GOCNPs in combination with propolis presents a promising new strategy for chemotherapy with reduced toxicity and enhanced biocompatibility. This novel approach has the potential to revolutionize the field of chemotherapy. Future studies should focus on the application of the encapsulated PE in various cancer cell lines, distinct gene expression factors, and cell cycles.


Subject(s)
Antioxidants , Cell Proliferation , Chitin , Chitosan , Nanoparticles , Oligosaccharides , Propolis , Humans , Propolis/chemistry , Propolis/pharmacology , Chitosan/chemistry , Antioxidants/pharmacology , Antioxidants/chemistry , Nanoparticles/chemistry , Oligosaccharides/chemistry , Oligosaccharides/pharmacology , Chitin/analogs & derivatives , Chitin/chemistry , Chitin/pharmacology , Cell Proliferation/drug effects , Hep G2 Cells , MCF-7 Cells , Drug Liberation , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry , Drug Carriers/chemistry , Drug Delivery Systems
9.
Food Chem ; 453: 139675, 2024 Sep 30.
Article in English | MEDLINE | ID: mdl-38781901

ABSTRACT

Bioproduction of diverse N-acetyl chitooligosaccharides from chitin is of great value. In the study, a novel GH family 18 bifunctional chitinase gene (PsChi82) from Paenibacillus shirakamiensis was identified, expressed and biochemically characterized. PsChi82 was most active at pH 5.0, and 55 °C, and displayed remarkable pH stability with the broad pH range of 3.0-12.0. It showed high chitosanase activity of 10.6 U mg-1 and diverse hydrolysis products of GlcNAc, (GlcNAc)2, GlcN-GlcNAc and (GlcN)2-GlcNAc, which may facilitate comprehensively understanding of structure-function relationships of N-acetyl COSs. Three engineered variants were then expressed and characterized. Among them, PsChi82-CBM26 possessed specific activity of 25.1 U mg-1 against colloidal chitin, which was 2.1 folds higher than that of PsChi82. The diverse N-acetyl COSs were subsequently produced by PsChi82-CBM26 with a sugar content of 23.2 g L-1. These excellent properties may make PsChi82-CBM26 potentially useful for N-acetyl COSs production in the food and chemical industries.


Subject(s)
Bacterial Proteins , Chitin , Chitinases , Chitosan , Oligosaccharides , Paenibacillus , Chitinases/chemistry , Chitinases/genetics , Chitinases/metabolism , Oligosaccharides/chemistry , Oligosaccharides/metabolism , Chitin/chemistry , Chitin/analogs & derivatives , Chitin/metabolism , Chitosan/chemistry , Chitosan/metabolism , Paenibacillus/enzymology , Paenibacillus/genetics , Paenibacillus/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Hydrogen-Ion Concentration , Enzyme Stability , Hydrolysis , Protein Engineering
10.
Toxins (Basel) ; 16(5)2024 May 09.
Article in English | MEDLINE | ID: mdl-38787069

ABSTRACT

The fungal cell wall serves as the primary interface between fungi and their external environment, providing protection and facilitating interactions with the surroundings. Chitin is a vital structural element in fungal cell wall. Chitin deacetylase (CDA) can transform chitin into chitosan through deacetylation, providing various biological functions across fungal species. Although this modification is widespread in fungi, the biological functions of CDA enzymes in Aspergillus flavus remain largely unexplored. In this study, we aimed to investigate the biofunctions of the CDA family in A. flavus. The A. flavus genome contains six annotated putative chitin deacetylases. We constructed knockout strains targeting each member of the CDA family, including Δcda1, Δcda2, Δcda3, Δcda4, Δcda5, and Δcda6. Functional analyses revealed that the deletion of CDA family members neither significantly affects the chitin content nor exhibits the expected chitin deacetylation function in A. flavus. However, the Δcda6 strain displayed distinct phenotypic characteristics compared to the wild-type (WT), including an increased conidia count, decreased mycelium production, heightened aflatoxin production, and impaired seed colonization. Subcellular localization experiments indicated the cellular localization of CDA6 protein within the cell wall of A. flavus filaments. Moreover, our findings highlight the significance of the CBD1 and CBD2 structural domains in mediating the functional role of the CDA6 protein. Overall, we analyzed the gene functions of CDA family in A. flavus, which contribute to a deeper understanding of the mechanisms underlying aflatoxin contamination and lay the groundwork for potential biocontrol strategies targeting A. flavus.


Subject(s)
Aflatoxins , Amidohydrolases , Aspergillus flavus , Aspergillus flavus/genetics , Aspergillus flavus/enzymology , Aspergillus flavus/metabolism , Amidohydrolases/genetics , Amidohydrolases/metabolism , Aflatoxins/biosynthesis , Aflatoxins/metabolism , Aflatoxins/genetics , Fungal Proteins/genetics , Fungal Proteins/metabolism , Chitin/metabolism , Cell Wall/metabolism
11.
Carbohydr Res ; 540: 109140, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38759342

ABSTRACT

Herein, we describe in first the application of squid pens for the preparation of pharmaceutical-grade oligochitosan hydrochloride with the physicochemical characteristics corresponding with the requirements of the European Pharmacopoeia. It is shown that the use of specific properties of squid pens as a source of parent chitosan allows preparing the product with a high yield at relatively moderate process conditions used for squid pens treatments and chitosan depolymerization.


Subject(s)
Chitin , Chitosan , Decapodiformes , Oligosaccharides , Chitosan/chemistry , Decapodiformes/chemistry , Oligosaccharides/chemistry , Oligosaccharides/chemical synthesis , Animals , Chitin/chemistry , Chitin/analogs & derivatives
12.
Carbohydr Res ; 540: 109144, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38733729

ABSTRACT

Chitooligosaccharides, the hydrolysis products of chitin, have superior biological activities and application value to those of chitin itself; however, the ordered and highly crystalline structure of chitin renders its degradation by chitinase difficult. Herein, the effects of plasma-activated water (PAW) pre-treatment on the physicochemical properties, crystal structure, and enzymatic hydrolysis of chitin were investigated. The hydrolysis of PAW-pre-treated chitin (PAW activation time of 5 min) using chitinase from Vibrio harveyi (VhChit2) yielded 71 % more reducing sugar, compared with that from untreated chitin, with the degree of chitin hydrolysis increasing from 13 % without pre-treatment to 23 % post-treatment. Moreover, the amount of VhChit2 adsorbed by chitin increased from 41.7 to 58.2 mg/g. Fourier transform infrared spectrometry revealed that PAW could break the ß-1,4-glycosidic bonds of chitin (but had no effects on the hydrogen and amido bonds), thereby decreasing the molecular weight and crystallinity of the polysaccharide, which caused its structural damage and enhanced its enzymatic hydrolysis by chitinase. Consequently, PAW pre-treatment can be considered a simple, effective, and environmentally-friendly method for the biotransformation of chitin as its easier hydrolysis yields high-value products.


Subject(s)
Chitin , Chitinases , Molecular Weight , Vibrio , Water , Chitinases/chemistry , Chitinases/metabolism , Chitin/chemistry , Chitin/metabolism , Chitin/analogs & derivatives , Water/chemistry , Hydrolysis , Vibrio/enzymology
13.
ACS Appl Mater Interfaces ; 16(23): 29856-29866, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38812116

ABSTRACT

The black corals possess a branched, tree-like skeleton that is composed of chitin fibrils embedded within a protein matrix. This skeleton exhibits growth rings interlocked by spines. The lamellae are tightly wrapped around the spines, creating a structure akin to an onion. The indentation hardness and Young's modulus of the spines are comparable to those of the chitin rings. The compressive stress and the fracture toughness are increased by approximately 14.6% and 32.2% at higher loading rate in the dry state, but remain comparable at different loading rates in the wet state. The lamellar interfaces have a tendency to resist sliding in the dry state. As a result, the lamellae that curve around the spines are prone to fracturing one by one, just like an onion being peeled. This allows the material to absorb more fracture energy, ensuring that the spines can effectively resist the lamellar delamination.


Subject(s)
Anthozoa , Anthozoa/chemistry , Animals , Elastic Modulus , Chitin/chemistry , Hardness
14.
mBio ; 15(6): e0092024, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38742885

ABSTRACT

Cryptococcus neoformans causes cryptococcal meningoencephalitis, a disease that kills more than 180,000 people annually. Contributing to its success as a fungal pathogen is its cell wall surrounded by a capsule. When the cryptococcal cell wall is compromised, exposed pathogen-associated molecular pattern molecules (PAMPs) could trigger host recognition and initiate attack against this fungus. Thus, cell wall composition and structure are tightly regulated. The cryptococcal cell wall is unusual in that chitosan, the acetylated form of chitin, is predominant over chitin and is essential for virulence. Recently, it was shown that acidic pH weakens the cell wall and increases exposure of PAMPs partly due to decreased chitosan levels. However, the molecular mechanism responsible for the cell wall remodeling in acidic pH is unknown. In this study, by screening for genes involved in cryptococcal tolerance to high levels of CO2, we serendipitously discovered that the aspartyl peptidase May1 contributes to cryptococcal sensitivity to high levels of CO2 due to acidification of unbuffered media. Overexpression of MAY1 increases the cryptococcal cell size and elevates PAMP exposure, causing a hyper-inflammatory response in the host while MAY1 deletion does the opposite. We discovered that May1 weakens the cell wall and reduces the chitosan level, partly due to its involvement in the degradation of Chs3, the sole chitin synthase that supplies chitin to be converted to chitosan. Consistently, overexpression of CHS3 largely rescues the phenotype of MAY1oe in acidic media. Collectively, we demonstrate that May1 remodels the cryptococcal cell wall in acidic pH by reducing chitosan levels through its influence on Chs3. IMPORTANCE: The fungal cell wall is a dynamic structure, monitoring and responding to internal and external stimuli. It provides a formidable armor to the fungus. However, in a weakened state, the cell wall also triggers host immune attack when PAMPs, including glucan, chitin, and mannoproteins, are exposed. In this work, we found that the aspartyl peptidase May1 impairs the cell wall of Cryptococcus neoformans and increases the exposure of PAMPs in the acidic environment by reducing the chitosan level. Under acidic conditions, May1 is involved in the degradation of the chitin synthase Chs3, which supplies chitin to be deacetylated to chitosan. Consistently, the severe deficiency of chitosan in acidic pH can be rescued by overexpressing CHS3. These findings improve our understanding of cell wall remodeling and reveal a potential target to compromise the cell wall integrity in this important fungal pathogen.


Subject(s)
Cell Wall , Cryptococcus neoformans , Fungal Proteins , Cryptococcus neoformans/genetics , Cryptococcus neoformans/enzymology , Cryptococcus neoformans/pathogenicity , Cell Wall/metabolism , Animals , Mice , Fungal Proteins/genetics , Fungal Proteins/metabolism , Aspartic Acid Proteases/genetics , Aspartic Acid Proteases/metabolism , Hydrogen-Ion Concentration , Cryptococcosis/microbiology , Cryptococcosis/pathology , Chitin/metabolism , Virulence , Inflammation/microbiology , Chitosan/metabolism , Host-Pathogen Interactions
15.
Nature ; 629(8014): 1158-1164, 2024 May.
Article in English | MEDLINE | ID: mdl-38750355

ABSTRACT

Plant pattern-recognition receptors perceive microorganism-associated molecular patterns to activate immune signalling1,2. Activation of the pattern-recognition receptor kinase CERK1 is essential for immunity, but tight inhibition of receptor kinases in the absence of pathogen is crucial to prevent autoimmunity3,4. Here we find that the U-box ubiquitin E3 ligase OsCIE1 acts as a molecular brake to inhibit OsCERK1 in rice. During homeostasis, OsCIE1 ubiquitinates OsCERK1, reducing its kinase activity. In the presence of the microorganism-associated molecular pattern chitin, active OsCERK1 phosphorylates OsCIE1 and blocks its E3 ligase activity, thus releasing the brake and promoting immunity. Phosphorylation of a serine within the U-box of OsCIE1 prevents its interaction with E2 ubiquitin-conjugating enzymes and serves as a phosphorylation switch. This phosphorylation site is conserved in E3 ligases from plants to animals. Our work identifies a ligand-released brake that enables dynamic immune regulation.


Subject(s)
Oryza , Plant Immunity , Plant Proteins , Ubiquitin , Animals , Chitin/metabolism , Homeostasis , Ligands , Oryza/enzymology , Oryza/immunology , Oryza/metabolism , Oryza/microbiology , Phosphorylation , Plant Proteins/antagonists & inhibitors , Plant Proteins/immunology , Plant Proteins/metabolism , Ubiquitin/metabolism , Ubiquitin-Conjugating Enzymes/metabolism , Ubiquitin-Protein Ligases/antagonists & inhibitors , Ubiquitin-Protein Ligases/chemistry , Ubiquitin-Protein Ligases/metabolism , Ubiquitination , Phosphoserine/metabolism , Conserved Sequence
16.
Molecules ; 29(9)2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38731405

ABSTRACT

Chitin, a ubiquitous biopolymer, holds paramount scientific and economic significance. Historically, it has been primarily isolated from marine crustaceans. However, the surge in demand for chitin and the burgeoning interest in biopolymers have necessitated the exploration of alternative sources. Among these methods, the mulberry silkworm (Bombyx mori) has emerged as a particularly intriguing prospect. To isolate chitin from Bombyx mori, a chemical extraction methodology was employed. This process involved a series of meticulously orchestrated steps, including Folch extraction, demineralization, deproteinization, and decolorization. The resultant chitin was subjected to comprehensive analysis utilizing techniques such as attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), 13C nuclear magnetic resonance (NMR) spectroscopy, and wide-angle X-ray scattering (WAXS). The obtained results allow us to conclude that the Bombyx mori represents an attractive alternative source of α-chitin.


Subject(s)
Bombyx , Chitin , Bombyx/chemistry , Animals , Chitin/chemistry , Chitin/isolation & purification , Spectroscopy, Fourier Transform Infrared , X-Ray Diffraction , Magnetic Resonance Spectroscopy , Morus/chemistry
17.
J Appl Microbiol ; 135(5)2024 May 01.
Article in English | MEDLINE | ID: mdl-38724455

ABSTRACT

AIMS: We aimed to investigate the function of an unidentified gene annotated as a PIG-L domain deacetylase (cspld) in Chitiniphilus shinanonensis SAY3. cspld was identified using transposon mutagenesis, followed by negatively selecting a mutant incapable of growing on chitin, a polysaccharide consisting of N-acetyl-d-glucosamine (GlcNAc). We focused on the physiological role of CsPLD protein in chitin utilization. METHODS AND RESULTS: Recombinant CsPLD expressed in Escherichia coli exhibited GlcNAc-6-phosphate deacetylase (GPD) activity, which is involved in the metabolism of amino sugars. However, SAY3 possesses two genes (csnagA1 and csnagA2) in its genome that code for proteins whose primary sequences are homologous to those of typical GPDs. Recombinant CsNagA1 and CsNagA2 also exhibited GPD activity with 23 and 1.6% of catalytic efficiency (kcat/Km), respectively, compared to CsPLD. The gene-disrupted mutant, Δcspld was unable to grow on chitin or GlcNAc, whereas the three mutants, ΔcsnagA1, ΔcsnagA2, and ΔcsnagA1ΔcsnagA2 grew similarly to SAY3. The determination of GPD activity in the crude extracts of each mutant revealed that CsPLD is a major enzyme that accounts for almost all cellular activities. CONCLUSIONS: Deacetylation of GlcNAc-6P catalyzed by CsPLD (but not by typical GPDs) is essential for the assimilation of chitin and its constituent monosaccharide, GlcNAc, as a carbon and energy source in C. shinanonensis.


Subject(s)
Chitin , Chitin/metabolism , Amidohydrolases/metabolism , Amidohydrolases/genetics , Acetylglucosamine/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism , Gammaproteobacteria/genetics , Gammaproteobacteria/enzymology , Gammaproteobacteria/metabolism
18.
Anal Methods ; 16(20): 3278-3286, 2024 May 23.
Article in English | MEDLINE | ID: mdl-38738557

ABSTRACT

Dextromethorphan (DXM) is a widely utilized central antitussive agent, which is frequently abused by individuals seeking its recreational effect. But DXM overdose can cause some adverse effects, including brain damage, loss of consciousness, and cardiac arrhythmias, and hence its detection is significant. Herein, an electrochemical sensor based on a Cu-coordinated molecularly imprinted polymer (Cu-MIP) was fabricated for its detection. For constructing the sensor, nitrogen-doped carbon nanosheets (CCNs) were prepared through calcining chitin under an argon atmosphere, and molybdenum disulfide (MoS2) was allowed to grow on their surface. Subsequently, the obtained MoS2/CCNs composite was employed to modify a glassy carbon electrode (GCE), and the Cu-MIP was electrodeposited on the electrode in a Cu-1,10-phenanthroline (Cu-Phen) solution containing DXM, where Cu2+ played a role in facilitating electron transfer and binding DXM. Due to the large specific surface area, good electrocatalytic properties and recognition of the resulting composite, the resulting Cu-MIP/MoS2/CCNs/GCE showed high selectivity and sensitivity. Under optimized experimental conditions, the peak current of DXM and its concentration exhibited a good linear relationship over the concentration range of 0.1-100 µM, and the limit of detection (S/N = 3) was 0.02 µM. Furthermore, the electrochemical sensor presented good stability, and it was successfully used for the determination of DXM in pharmaceutical, human serum and urine samples.


Subject(s)
Carbon , Copper , Dextromethorphan , Disulfides , Electrochemical Techniques , Molecularly Imprinted Polymers , Molybdenum , Molybdenum/chemistry , Disulfides/chemistry , Dextromethorphan/analysis , Dextromethorphan/chemistry , Dextromethorphan/urine , Copper/chemistry , Electrochemical Techniques/methods , Carbon/chemistry , Molecularly Imprinted Polymers/chemistry , Chitin/chemistry , Humans , Limit of Detection , Electrodes , Antitussive Agents/chemistry , Antitussive Agents/analysis , Antitussive Agents/urine
19.
Environ Res ; 252(Pt 4): 119065, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38723990

ABSTRACT

The present research study combines chitin from shrimp waste with the oxide-rich metakaolin. Metakaolin is a blend of mixed oxides rich in silica and alumina with good adsorbent properties. The chitin@metakaolin (CHt@M.K.) composite was synthesized and characterized using FTIR, SEM, TGA, XRD and XPS techniques. Cr(VI) removal studies were compared for chitin and CHt@M.K. through adsorption. It was found that the adsorption capacity of CHt@M.K. is 278.88 mg/g, almost double that of chitin, at pH 5.0 in just 120 min of adsorption. Isotherm models like Langmuir, Freundlich, Temkin and Dubinin-Radushkevich were investigated to comprehend the adsorption process. It was revealed that Langmuir adsorption isotherm is most suitable to elucidate Cr(VI) adsorption on CHt@M.K. The adsorption kinetics indicate that pseudo first order was followed, indicating that the physisorption was the process that limited the sorption process rate. The positive enthalpy change (20.23 kJ/mol) and positive entropy change (0.083 kJ/mol K) showed that the adsorption process was endothermic and more random at the solid-liquid interface. The negative free energy change over entire temperature range was an indicator of spontaneity of the process. Apart from all these, the non-covalent interactions between Cr(VI) and composite were explained by quantum calculations based models.


Subject(s)
Animal Shells , Chitin , Chromium , Water Pollutants, Chemical , Chitin/chemistry , Animals , Chromium/chemistry , Adsorption , Water Pollutants, Chemical/chemistry , Animal Shells/chemistry , Brachyura/chemistry , Kinetics
20.
J Agric Food Chem ; 72(22): 12655-12664, 2024 Jun 05.
Article in English | MEDLINE | ID: mdl-38775266

ABSTRACT

Using Lactiplantibacillus plantarum as a food-grade carrier to create non-GMO whole-cell biocatalysts is gaining popularity. This work evaluates the immobilization yield of a chitosanase (CsnA, 30 kDa) from Bacillus subtilis and a mannanase (ManB, 40 kDa) from B. licheniformis on the surface of L. plantarum WCFS1 using either a single LysM domain derived from the extracellular transglycosylase Lp_3014 or a double LysM domain derived from the muropeptidase Lp_2162. ManB and CsnA were fused with the LysM domains of Lp_3014 or Lp_2162, produced in Escherichia coli and anchored to the cell surface of L. plantarum. The localization of the recombinant proteins on the bacterial cell surface was successfully confirmed by Western blot and flow cytometry analysis. The highest immobilization yields (44-48%) and activities of mannanase and chitosanase on the displaying cell surface (812 and 508 U/g of dry cell weight, respectively) were obtained when using the double LysM domain of Lp_2162 as an anchor. The presence of manno-oligosaccharides or chito-oligosaccharides in the reaction mixtures containing appropriate substrates and ManB or CsnA-displaying cells was determined by high-performance anion exchange chromatography. This study indicated that non-GMO Lactiplantibacillus chitosanase- and mannanase-displaying cells could be used to produce potentially prebiotic oligosaccharides.


Subject(s)
Bacillus subtilis , Bacterial Proteins , Glycoside Hydrolases , Peptidoglycan , Bacillus subtilis/genetics , Bacillus subtilis/enzymology , Bacillus subtilis/chemistry , Bacillus subtilis/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Bacterial Proteins/chemistry , Glycoside Hydrolases/genetics , Glycoside Hydrolases/chemistry , Glycoside Hydrolases/metabolism , Peptidoglycan/metabolism , Peptidoglycan/chemistry , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/genetics , Enzymes, Immobilized/metabolism , Protein Domains , Lactobacillus plantarum/genetics , Lactobacillus plantarum/enzymology , Lactobacillus plantarum/metabolism , Lactobacillus plantarum/chemistry , Chitin/metabolism , Chitin/chemistry
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