Search Results (290)

Melting leakage and low thermal conductivity of stearic acid (SA) restrict its application in thermal storage. In this work, a shape-stabilized phase change material (ECNX/SA) with enhanced thermal storage performance and photothermal conversion is designed based on expanded graphite/chitin-derived carbon (ECNX). Thermal storage performance, including phase change temperature, enthalpy, thermal conductivity and shape stability, of ECNX/SA is investigated. With this, the influence mechanism of ECNX on the thermal storage performance is characterized via N₂ isothermal adsorption–desorption, FTIR, XRD and SEM. Results show that the prepared ECN15/SA has ideal thermal storage performance, where its phase change enthalpy and thermal conductivity are 121.59 J/g and 1.573 W/(m·K), respectively, and possesses superior shape stability. Moreover, the thermal storage performance of ECN15/SA keeps stable even undergoing several thermal cycles, and its photothermal conversion is as high as 89.2%. Characterizations suggest that ECN15 with a hierarchical pore structure and a high graphitization degree to enhance the shape stability and thermal conductivity of SA. Therefore, the prepared ECN15/SA is potential using in thermal storage. Full article

As the demand for chitin grows, new chitin sources with unique physicochemical properties are required. Abundant biofouling species, such as amphipods and hydroids, have chitinous skeletal systems that can be utilized for chitin production. However, little is known about these chitin sources. This study investigated the viability of amphipods (Jassa sp.) and hydroids (Coryne sp.) obtained from aquaculture biofouling assemblages as novel sources of chitin. Chitin was extracted from these sources and characterized in terms of its degree of acetylation (DA), crystallinity index (CrI), molecular weight (MW), thermal stability, and surface morphology. Physiochemical characteristics where then compared against commercially available shrimp chitin. Results show that a 32.75% chitin yield can be obtained from hydroids. The percentage DA for amphipod (AC) and hydroid (HC) chitin is 58.4–59.2% and 64.8–66.7%, respectively. AC is characterized as α-chitin with a low molecular weight (MW), while HC is medium-MW β-chitin. This finding is significant because it shows hydroids to be a new source of rare β-chitin. In addition, AC has higher thermal stability than HC. AC and HC greatly differ in terms of surface morphology. Therefore, the chitin biomaterials extracted from amphipods and hydroids have different but favorable properties that can be used for diverse applications. Full article

This study presents the first assessment of the combined effect of vanillin and chitin particles on the rheological, oil retention, textural, and oxidative properties of chitosan-based oleogels formulated with olive oil. Oleogels were prepared with and without vanillin; in the latter case, the vanillin-to-chitosan ratio was kept constant (1.3), while chitin concentrations (% w/w) were variable (0.0, 0.5, 1.5, and 2.0). Fresh oleogels and those stored for 15 days were characterized. Results demonstrated that vanillin promotes the formation of compact viscoelastic networks, enhances the elastic modulus by approximately 1.3 times, improves oil binding capacity from 75.1% to 89.2%, and significantly improves oxidative stability by minimizing lipid degradation. In contrast, the influence of chitin was dependent on its content and the presence of vanillin. At intermediate content, chitin positively affected cohesiveness and elasticity, particularly in vanillin-free systems. However, in formulations containing vanillin, even low chitin concentration disrupted the gel network, leading to a decrease in hardness, low oil retention, and a higher oxidation degree. Significant correlations between hardness and elastic modulus, oil binding capacity, adhesiveness, and damping factor were obtained for fresh and stored oleogels. Full article

The black bug, Antiteuchus tripterus (Hemiptera: Pentatomidae), is one of the most important pests of cacao in Peru. Its control relies primarily on synthetic insecticides, which negatively impact the environment and the health of cacao farmers. Therefore, the use of natural enemies, such as entomopathogenic fungi, represents a promising and sustainable alternative. In this study, we aimed to characterize entomopathogenic fungal isolates obtained from naturally infected A. tripterus adults in Peru. Using morphological and molecular approaches, we identified the isolates as Purpureocillium takamizusanense. Then, we assessed their pathogenic potential against A. tripterus and identified their functional cell wall groups. To evaluate pathogenicity, A. tripterus nymphs were exposed to serially diluted conidial suspensions (10⁵–10⁹ conidia mL⁻¹; isolate 24M) in both laboratory and field trials. The isolates exhibited conidial viability above 99%. Concentration-mortality bioassays confirmed the lethal effect of P. takamizusanense against A. tripterus nymphs. The LC₅₀ was 1.65 × 10⁶ conidia mL^–1, while the LT₅₀ and LT₉₀ were 3.08 and 7.29 days, respectively. The field mortality rate was about 52%, which can be explained by the influence of the environment. Spectroscopy analyses revealed functional groups including chitin, glucans, lipids, aliphatic chains, and proteins, which may contribute to infection and fungal persistence. This study presents the first record of P. takamizusanense in the Americas and highlights its potential as a biocontrol agent against A. tripterus in cacao plantations. Full article

Fusarium head blight (FHB) negatively affects wheat yield and quality worldwide. As wheat varieties differ in terms of their resistance to FHB, the identification of FHB-resistant genes is of great importance for the genetic improvement for FHB resistance in wheat breeding. Although sugar transporter proteins (STPs) play vital roles in plant–pathogen interactions, the functions of STP genes in wheat FHB resistance remain poorly understood. In this study, bioinformatics analyses were conducted to identify novel STP genes and characterize their expression profiles in wheat. We confirmed the presence of the 81 TaSTP genes previously reported and identified one additional member, designated as TaSTP6-2D. Based on RNA-seq profiles, 50 TaSTP genes that showed differential expression under biotic or abiotic stress were selected to explore the potential function in the resistance to Fusarium head blight. RT-qPCR analysis revealed that 11 TaSTP genes (TaSTP1-2D, TaSTP3-2A, TaSTP3-2B, TaSTP6-2A, TaSTP6-2B, TaSTP13-4B, TaSTP13-4D, TaSTP19-4A, TaSTP26-5A, TaSTP28-3A and TaSTP28-3D) were differential expressed following the treatment with chitin, Fusarium graminearum or deoxynivalenol. Among them, TaSTP26-5A showed a 28-fold upregulation to chitin in “Yangmai 158” compared to a 6-fold change in “Fielder”. These findings establish a foundation for understanding the function of TaSTP genes in FHB resistance and provide potential genetic targets for improving disease resistance in wheat. Full article

Chitin synthase (CHS) is essential for maintaining exoskeletal integrity and environmental adaptability in insects. CHS genes are categorized into two types, CHS1 and CHS2. Hemipteran insects possess only the CHS1 gene due to the absence of a peritrophic matrix (PM) in their midgut. However, the identification and functional characterization of the CHS1 gene in Pentatomidae species have not been reported. This study reports the first identification of a CHS gene, ArmaCHS1, from the predatory stink bug, Arma chinensis, and investigates its role in response to temperature stress. The ArmaCHS1 open reading frame spans 4407 bp, encoding a protein of 1468 amino acids, with 14 transmembrane helices and seven N-glycosylation sites. Phylogenetic analysis confirmed its classification within the CHS1 clade, closely related to CHS1 from Halyomorpha halys. qRT-PCR analysis revealed that ArmaCHS1 is predominantly expressed in the exoskeleton and displays developmentally regulated expression (lowest in eggs, highest in adults). Temperature stress experiments demonstrated that ArmaCHS1 expression was significantly upregulated at low temperatures (12 °C, 19 °C) and markedly downregulated at high temperatures (33 °C, 40 °C). These findings indicate that ArmaCHS1 likely contributes to thermal adaptation in A. chinensis by modulating chitin biosynthesis, providing new insights into the environmental stress responses of beneficial predatory insects. Full article

Microorganisms with chitin-degrading capabilities play a crucial role in the biological control of crop pests and diseases as well as in the treatment of organic waste. In this study, a chitin-degrading bacterium, designated L2-2, was isolated from the intestine of Odorrana margaretae collected in Mount Emei, Sichuan, China. Based on physiological and biochemical characteristics, 16S rRNA gene sequencing, and phylogenetic analysis of 31 conserved housekeeping genes in the whole genome, strain L2-2 was identified as a member of the genus Roseateles, named Roseateles sp. L2-2. This strain is able to grow on agar medium with colloidal chitin as the sole carbon source and form clear hydrolysis zones. After optimizing fermentation conditions (including concentrations of nitrogen and carbon sources, culture time, and pH), the enzyme activity was increased to 3.46 U/mL, which was 24 times higher than the initial enzyme activity. Functional genome annotation showed that the strain contains genes encoding endochitinases of the GH18, GH23, and GH46 families, as well as genes encoding β-glucosidases of the GH1, GH2, GH3, and GH109 families, indicating its genetic basis for chitin-degrading potential. This study expands the diversity of known chitin-degrading bacteria and provides a promising microbial resource for the bioremediation of chitinous waste and sustainable pest control in agriculture. Full article

The velvet complex is a master regulator of multiple physiological processes in filamentous fungi. In this study, we characterized the functions of velvet gene FpvelC in Fusarium proliferatum, which was the causative agent of rice spikelet rot disease. Compared with the wild-type Fp9 strain, deletion of FpvelC hindered conidiation, leading to a low level of trehalose content but excessive accumulation of chitin in conidia. Lack of FpvelC resulted in increased sensitivity to oxidative stress and decreased expression of antioxidant genes. Notably, ΔFpvelC exhibited attenuated pathogenicity on rice and maize, failure to produce invasive hyphae, and downregulation of genes encoding xylanases and xyloglucanases during infection processes. Nevertheless, disruption of FpvelC enhanced production of fumonisin B1 (FB1) and fusaric acid concomitantly; transcripts of the clustering genes responsible for the two mycotoxins’ biosynthesis were significantly increased. Additionally, the absence of FpvelC was displayed as more sensitive to rapamycin than the Fp9 strain, accompanied with less intracellular glutamine. Overall, FpvelC played versatile roles in conidiation, response to oxidative stress, pathogenicity and mycotoxins production in F. proliferatum. Full article

Biopolymers have gained significant attention due to their environmental advantages, with insects emerging as a promising but underutilized source of chitin and chitosan. In this study, chitosan was extracted from the larval exuviae of Tenebrio molitor through sequential demineralization, deproteinization, and deacetylation steps. For selected analyses, the extracted chitosan was further purified via reprecipitation from an acid solution using a basic precipitant (1 M NaOH). Chitosan was then characterized using chemical and instrumental methods. The results indicated that the chitosan had a medium degree of deacetylation (72.27%) and viscosity-average molecular weight (612 kDa), along with minimal ash (0.33%) and amino acid (0.14%) content, suggesting high product quality. FTIR analysis identified characteristic functional groups present, and SEM analysis highlighted a fibrous and porous microstructure in the purified chitosan. The prepared films exhibited favorable properties, including low thickness (0.0197 mm), high swelling degree (335.07%), moderate water solubility (46.99%), and moisture content of 32.39%, supporting their practical applicability. T. molitor exuviae thus represents a sustainable and environmentally friendly source of high-quality chitosan, with beneficial structural and functional properties, supporting its use in a wide array of value-added applications. Full article

Lytic polysaccharide monooxygenases (LPMOs) represent copper-dependent enzymes pivotal in breaking down resilient polysaccharides like cellulose and chitin by means of oxidation, creating more accessible sites for glycoside hydrolases. To elevate the conversion efficiency of chitin, an AA10 LPMO was identified from the genome of Saccharophagus degradans 2-40^T and heterologously expressed. The optimal pH for the activity of recombinant SdLPMO10A is 9.0, and the optimal temperature is 60 °C. Assessment of SdLPMO10A’s synergism with commercial chitinase indicated that when comparing the enzyme combination’s activity to the activity of chitinase alone, the synergistic effect was significant, and a one-pot reaction appeared superior to a two-step reaction. This discovery of a functional AA10 family LPMO presents a promising avenue for developing highly efficient catalysts for biomass conversion of chitin-rich food processing waste (e.g., shrimp shells) into bioactive chitooligosaccharides with applications in functional foods, such as prebiotics and antioxidants. Full article

The Colorado potato beetle (Leptinotarsa decemlineata, CPB) is a major pest in potato crops, notorious for its rapid dispersal and insecticide resistance, which are enabled by its robust elytra and flight-capable hindwings. The Miniature (Mi) gene, encoding a protein with a zona pellucida (ZP) domain, is involved in wing development and cuticle integrity, yet its functional role in beetles remains underexplored. In this study, we cloned and characterized the LdMi gene in the CPB and investigated its function using RNA interference (RNAi), morphological analyses, and spectroscopy. LdMi encodes a 146.35 kDa transmembrane protein with a conserved ZP domain, clusters with coleopteran homologs, and exhibits relative conservation across insect species. Expression profiling showed high LdMi transcript levels in the hindwings, the elytra, and the pupal stages. RNAi knockdown in fourth-instar larvae resulted in severe eclosion defects, including malformed wings and reduced adult weight. Scanning electron microscopy (SEM) revealed disrupted elytral patterns and deformed hindwing veins in knockdown individuals. Spectroscopic analyses using Fourier-transform infrared (FTIR) and Raman spectroscopy indicated a reduction in protein–chitin crosslinking and diminished hydrogen bonding, suggesting compromised cuticular integrity. These results highlight the essential role of LdMi in cuticle formation and the surface morphology of the elytra and hindwings, offering new insights into ZP domain proteins in insects. Full article

Brettanomyces bruxellensis has been described as the main spoilage microorganism in wines due to its ability to produce volatile phenols, which negatively impact the final product’s organoleptic properties. This yeast can grow and survive in environments that are too nutritionally poor and stressful for other microorganisms, and one of the stressful conditions it can endure is the high alcohol content in wine. In this study, cell wall morphology and the expression of some genes related to its composition were characterized under increasing ethanol concentrations to establish a possible ethanol resistance mechanism. B. bruxellensis LAMAP2480 showed greater resistance to β-1,3-glucanase activity when grown in media supplemented with 5% or 10% ethanol compared with the control assay (without ethanol). Transmission electron microscopy showed no significant differences in cell wall thickness during the different adaptation stages. However, the amount of wall polysaccharides and chitin briefly increased at 1% ethanol but returned to baseline at 5% and 10%. The amount of wall-associated protein increased progressively with each increment in ethanol concentration. In addition, overexpression of the ROM2 and KNR4/SMI1 genes was observed at 10% ethanol. These results suggest that the integrity of the cell wall might play an important role in the adaptation of B. bruxellensis to an ethanol-containing medium. Full article

This study is an effort to optimize the thermal properties of refined, bleached, and deodorized (RBD) oil by incorporating bionanoparticles. This study investigates the impact on thermal conductivity and thermal diffusivity by incorporating chitosan nanoparticles (CS-NPs) at different temperatures with varying weight fractions of NPs. To the best of our knowledge, these synthesized CS-NPs from oyster mushrooms (Pleurotus ostreatus) and commercial marine-sourced CS-NPs are used for the first time to prepare nanofluids. These nanofluids offer high potential for industrial applications due to their biodegradability, biocompatibility, and nontoxicity. Fungal-sourced chitosan is a vegan-friendly alternative and does not contain allergic compounds, such as marine-sourced chitosan. The CS-NPs were synthesized using a chemical and mechanical treatment process at three different amplitudes, and CS-NPs at amplitude 80 were selected to prepare the nanofluid. Chitin, chitosan, and CS-NPs were characterized by the FTIR-ATR method, while the size and morphology of the CNs were analyzed by SEM. Thermal conductivity and thermal diffusivity of nanofluids and base fluid were measured using a multifunctional thermal conductivity meter (Flucon LAMBDA thermal conductivity meter) by ASTM D7896-19 within the temperature range 40–160 °C with step size 20. The thermal conductivity values were compared between commercial CS-NPs and synthesized CS-NPs treated with RBD palm olein with different weight percentages (0.01, 0.05, and 0.1 wt.%). It was confirmed that the thermal properties were enhanced in both kinds of nanoparticles added to RBD palm olein, and higher enhancement was observed in fungal-sourced CS-NPs treated with RBD palm olein. Maximum enhancement of thermal conductivity of commercial and synthesized CS-NPs treated with RBD palm olein were 4.28% and 7.33%, respectively, at 0.05 wt.%. Enhanced thermal conductivity of RBD palm olein by the addition of CS-NPs facilitates more effective heat transfer, resulting in quicker and more consistent cooking and other potential heat transfer applications. Full article

The exoskeleton of insects, known as the cuticle, necessitates regular renewal during molting and metamorphosis, with chitin being its primary structural component. Consequently, the molting and metamorphosis processes in insects are characterized by periodic degradation and synthesis of chitin, which are tightly regulated by juvenile hormone (JH) and 20-hydroxyecdysone (20E). Propsilocerus akamusi, a species that plays a crucial role in freshwater ecosystems, demonstrates remarkable resilience to environmental pollutants, including metallic elements found in industrial waste. In this investigation, we systematically analyzed and summarized the metabolic pathways associated with JH, 20E, chitin, and heavy metal transport in P. akamusi. Based on previous genome assembly, we conducted a systematic annotation and functional analysis of genes involved in these metabolic pathways in P. akamusi. This was achieved by querying conserved domains using Pfam and SMART, as well as identifying gene-specific classical consensus regions through amino acid sequence alignment using DNAMAN. Through our validation, a total of 109 genes were definitively categorized into four distinct metabolic pathways: 27 genes were involved in the JH metabolic pathway, 24 in the 20E metabolic pathway, 27 in the chitin metabolic pathway, and 31 in metal transport pathways. A total of 30 genes failed our validation and were temporarily excluded. Furthermore, through RNA sequencing (RNA-seq)-based transcriptome analysis, we observed that under copper (Cu) stress, the expression levels of the majority of genes participating in these metabolic pathways in P. akamusi were altered. This finding suggests that copper exposure influences the molting process in P. akamusi. Full article

Chitin synthase (CHS) plays a key role in chitin synthesis. CHS1 is ubiquitous in insects, and some studies have found that the RNA interference with CHS1 can hinder three types of molting processes (larva–larva, larva–pupa and pupa–adult). In the present study, the CHS1 of Monochamus alternatus was identified and characterized by a bioinformatics analysis. The developmental stage-specific expression of the MalCHS1 (Monochamus alternatus CHS1) gene was obtained by a RT-qPCR, and the corresponding dsRNA was designed for functional verification. The RNA interference experiment was conducted using the microinjection method, and the injection site was selected from the abdominal segments of fifth-instar larvae. The results showed that after silencing the CHS1 gene, the larvae of M. alternatus showed morphological abnormalities, such as the softening of the body wall, a transparent abdomen and the swelling of somites, indicating that MalCHS1 mediates the molting, growth and development of M. alternatus. RNAi-mediated MalCHS1 gene silencing may become a promising new biological pesticide that can provide a new target gene for pest control. Full article