Chitin is an abundant aminopolysaccharide found in insect pests and phytopathogenic microorganisms but absent in higher plants and vertebrates. It is crucial for mitigating threats posed by chitin-containing organisms...Chitin is an abundant aminopolysaccharide found in insect pests and phytopathogenic microorganisms but absent in higher plants and vertebrates. It is crucial for mitigating threats posed by chitin-containing organisms to human health, food safety, and agriculture. Therefore, targeting the chitin biosynthesisassociated bioprocess holds a promise for developing human-safe and eco-friendly antifungal agents or pesticides. Chitin biosynthesis requires chitin synthase and associated factors, which are involved in the modification, regulation, organization or turnover of chitin during its biosynthesis. A number of enzymes such as chitinases, hexosaminidases, chitin deacetylases are closely related and therefore are promising targets for designing novel agrochemicals that target at chitin biosynthesis. This review summarizes the advances in understanding chitin biology over the past decade by our research group and collaborates,specifically regarding essential proteins linked to chitin biosynthesis that can be exploited as promising pesticide targets. Examples of small bioactive molecules that against the activity of these targets are given.展开更多
Chitin is an abundant natural biopolymer that plays a crucial role in insect growth and development as a fundamental structural component of the exoskeleton.The membrane-integralβ-glycosyltransferase,chitin synthase,...Chitin is an abundant natural biopolymer that plays a crucial role in insect growth and development as a fundamental structural component of the exoskeleton.The membrane-integralβ-glycosyltransferase,chitin synthase,has been identified as the central component in chitin biosynthesis.However,the precise roles of other proteins in facilitating chitin synthase in chitin biosynthesis remain unclear.In this study,we employed split-ubiquitin membrane yeast two-hybrid(MYTH)and pull-down assays to demonstrate the physical interaction between Twinstar(Tsr),a small molecular protein in the actin-depolymerizing factor ADF/Cofilin protein family,and chitin synthase Krotzkopf verkehrt(Kkv)in Drosophila melanogaster in vitro.The RNA interference(RNAi)-mediated global knockdown of Tsr in D.melanogaster resulted in larval lethality.Furthermore,targeted suppression of Tsr in the tracheal and epidermal tissues also led to larval mortality,while knocking down Tsr in the wing tissues led to wrinkled wings.Additionally,silencing Tsr not only reduced the chitin content in the first longitudinal vein of the wings but also led to the absence of the chitin lamellar structure.To validate the functional conservation of Tsr in other insect orders,the two agricultural pests Ostrinia furnacalis and Tribolium castaneum,representing lepidoptera and coleoptera insects,respectively,were investigated.Knockdown experiments targeting the Drosophila Tsr orthologues OfTsr in O.furnacalis and TcTsr in T.castaneum produced abnormal larvae during molting or pupation in O.furnacalis and lethality in T.castaneum.Our findings not only improve ourknowledge of the chitin biosynthesis machinery in insect cuticles but also provide new potential targets for the control of major agricultural pests.展开更多
LysM proteins contain the lysin domain(LysM),bind chitin and are found in various organisms including fungi.In phytopathogenic fungi,certain LysM proteins act as effectors to inhibit host immunity,thus increasing fung...LysM proteins contain the lysin domain(LysM),bind chitin and are found in various organisms including fungi.In phytopathogenic fungi,certain LysM proteins act as effectors to inhibit host immunity,thus increasing fungal virulence.However,our understanding of the LysM protein family in Setosphaeria turcica is limited.In this study,eight StLysM genes are identified and designated as StLysM1 to StLysM8.The analysis of sequence features indicates that five proteins(StLysM1,StLysM2,StLysM5,StLysM6,and StLysM7)are potential effectors.Phylogenetic analysis suggests that the StLysMs are divided into fungal/bacterial and fungus-specific subclasses.Domain architecture analysis reveals that the five StLysM effectors exclusively harbor the LysM domain,whereas the other three StLysM proteins contain additional functional domains.Sequence conservation analysis shows that the fungal-specific LysM domain sequences share the ^(8)GDxTC^(12) and ^(29)WNP^(31) motifs as well as three highly conserved cysteine residues.Conversely,the LysM domain sequences from the bacterial/fungal branch have few conserved sites.Moreover,expression profiling analysis shows that the StLysM1 gene is significantly upregulated during the infection of maize.Yeast secretion assays and transient expression experiments demonstrate that StLysM1 is a secreted protein that can suppress BAX/INF1-induced programmed cell death in Nicotiana benthamiana.Further functional analysis suggests that St Lys M1 cannot interact with itself but it can bind chitin.The transient expression of StLysM1 inhibits the chitin-triggered plant immune response,increasing susceptibility to the phytopathogenic fungus Botrytis cinerea in N.benthamiana.This study reveals that the S.turcica LySM protein family consists of eight members,highlighting the significance of StLysM1 as a vital effector in regulating plant immunity.The results provide insight into StLysMs and establish a foundation for understanding the roles of StLysM proteins in the pathogenic process of S.turcica.展开更多
In the last decade,shell biorefinery,a novel concept referring to the extraction of the main components of crustacean shells and the transformation of each component into valuable products,was proposed and has attract...In the last decade,shell biorefinery,a novel concept referring to the extraction of the main components of crustacean shells and the transformation of each component into valuable products,was proposed and has attracted increasing attentions.Chitin is one of main components of crustacean shells.Owing to the bio-fixed nitrogen element,chitin biomass has been regarded as a good candidate to produce nitrogen-containing chemicals.Among these,3-acetamido-5-acetylfuran(3A5AF)is an interesting furanic compound derived from the hydrolysis and sequential dehydration of chitin.Similar to cellulose-derived platform chemical 5-hydromethylfurfural(HMF),3A5AF is an emerging platform compound and also can be converted into various useful chemicals by oxidation,reduction,hydrolysis,substitution,and so on.This review showcases the recent advances in the synthesis of 3A5AF from chitin and N-acetyl glucosamine(NAG)employing various catalytic systems.The conversion of 3A5AF into valuable compounds was introduced then.There are still some challenges in this area,for example,the rational design of green and efficient catalytic systems for the synthesis of 3A5AF and its derivatives.The outlooks also were discussed at the end of the review.展开更多
Chitin,distinguished by its nitrogen-rich acetamido and amino groups,imparts a distinctive cationic nature,enabling chitin to have indispensable features in various applications.Despite its significant promise in the ...Chitin,distinguished by its nitrogen-rich acetamido and amino groups,imparts a distinctive cationic nature,enabling chitin to have indispensable features in various applications.Despite its significant promise in the textile industry,particularly for sustainable and functional fabric applications,the practical utilization of chitin fibers remains constrained by insufficient mechanical strength.The degree of deacetylation(DD),a key molecular-level structural determinant,has not been adequately addressed in previous studies despite its critical role in influencing chitin properties across multiple scales.In this study,a deacetylation-mediated design strategy was used to achieve enhanced mechanical performance coupled with multifunctional efficacy using an aqueous KOH/urea solution dissolution system.We prepared a series of deacetylated chitins with different DD values and systematically studied the effect of deacetylation on the multiple-scale structure of regenerated fibers,such as intermolecular interactions and chain orientation at the molecular level,and the aggregation behavior of chitin nanofibers within the gel-state and dried fibers at the micro/nano scale.To achieve an enhanced mechanical performance coupled with multifunctional efficacy by relying on an aqueous KOH/urea solution dissolution system.Moreover,deacetylation enhances intermolecular interactions,resulting in densified internal structures and improved fiber orientation.Concomitantly,it augmented the antimicrobial functionality of the fibers.This deacetylation-mediated design strategy provides a deeper understanding of the structure and properties of regenerated chitin and advances the utility of chitin in strong and sustainable fibers.展开更多
The conversion process of chitin,one of the abundant biomass resources on the earth,not only follows the principles of green chemistry,but also has significant value in industrial applications.However,it is a great ch...The conversion process of chitin,one of the abundant biomass resources on the earth,not only follows the principles of green chemistry,but also has significant value in industrial applications.However,it is a great challenge to directly convert insoluble and rigid structured chitin to 5-hydroxymethylfurfural(HMF).To address this issue,we developed a green conversion process combining pretreatment and catalytic system.Chitin was first pretreated by hexafluoro isopropanol(HFIP),which somewhat disrupted the hydrogen bonding network within the chitin structure.Subsequently,formic acid(FA)and silicotungstic acid(STA)synergistically catalyzed the conversion to HMF in a biphasic system of 2-methyltetrahydrofuran(2-Me-THF)/H2O,and high yields(40.2%)HMF was obtained under the optimism conditions.The product distribution was analyzed by HPLC-MS and the co-catalysis of FA with STA was evidenced.A dual-function catalytic system with both Lewis and Br?nsted acids was created,the catalytic system that significantly improved the efficiency of complex tandem catalytic reactions with chitin.Based on the experimental results,a possible pathway for chitin conversion was deduced,providing a new catalytic idea for the efficient conversion of chitin to HMF.展开更多
[Objective] The aim of this study was to optimize the conditions of chitinase-produce strains.[Method] A kind of screened chitinase-produce strain G-254 was habituated cultured,and then the single factor experiment wa...[Objective] The aim of this study was to optimize the conditions of chitinase-produce strains.[Method] A kind of screened chitinase-produce strain G-254 was habituated cultured,and then the single factor experiment was carried out to explore the effects of different carbon source,nitrogen source and inorganic salt on the activity of produced chitinase;the response surface test was used to determine the optimal conditions for chitinase production.[Result] The optimal conditions for chitinase production were：8% of glucose,5% of beef extract and 0.07% of MgSO4,and the activity of chitinase reached the maximal value（6.86 U）under these conditions.[Conclusion] The study improved the activity of chitinase produced by strain G-254 and provided good foundation for industrial production.展开更多
The industrial processing of shrimp produces massive quantities of solid waste that is a notable source of animal protein, chitin, carotenoids, and other bioactive compounds that are not appropriately utilized. In the...The industrial processing of shrimp produces massive quantities of solid waste that is a notable source of animal protein, chitin, carotenoids, and other bioactive compounds that are not appropriately utilized. In the present study, chitin and protein extraction from shrimp head with autolysis and fermentation using Bacillus licheniformis were investigated. The results showed that when shrimp heads were autolyzed with a natural pH at 50℃ for 4 h, the total amino acid nitrogen in the supernatant was 5.01 mg mL^-1. Then, when a 50%(v/m) inoculum of the hydrolysate was incubated at 60℃ for 10 h, a deproteinization rate of 88.3% could be obtained. The fermented supernatant was processed into a dry protein powder, while the residues were demineralized by 10% citric acid for chitin. The recovered protein powder contained 5.5% moisture, 11.5% ash, and 66.7% protein, while the chitin contained 3.5% moisture, 2.1% ash, and 3.1% protein. In addition, amino acids, minerals, heavy metals, the degree of acetylation, microstructure, and Fourier-transform infrared(FT-IR) spectroscopy results were analyzed. Furthermore, the statistics of the large scale trial after treatment with 20 kg of shrimp heads were analyzed. Thus, this work made the shrimp waste utilization environmentally sound and valuable.展开更多
Chitin is an abundant natural nitrogen-containing biopolymer with great application potential in materials,environment,energy,and health.However,the structure characteristics and processing technologies have required ...Chitin is an abundant natural nitrogen-containing biopolymer with great application potential in materials,environment,energy,and health.However,the structure characteristics and processing technologies have required intense research in related applications.In particular,there have been great efforts to developing solvents for chitin,and the results s0 far are quite encouraging.This review summarizes the main solvent systems used for chitin,namely the aqueous solvent systems(mineral acids,inorganic salt aqueous solutions,alkali aqueous solutions)and non aqueous ones(LiCl-dimethylacetamide solvents,CaCl22H2O saturated methanol,ionic liquids,deep eutectic solvents,and protic organic solvents).The solvent properties,dissolution methods,and solution properties are discussed in detail.Special attention is paid to the dissolution mechanism in each system.This review can provide a reference for understanding the dissolution behavior of chitin and finding suitable solvents for it.展开更多
This study intends to examine the effects of different concentrations of four kinds of degradations of chitin： glucosamine （GLC）, N-acetyl-D-glucosamine （NAG）, chitooligosaccharide（COS）, CM-chitooligosaccharide...This study intends to examine the effects of different concentrations of four kinds of degradations of chitin： glucosamine （GLC）, N-acetyl-D-glucosamine （NAG）, chitooligosaccharide（COS）, CM-chitooligosaccharide （CM-COS）—on the proliferation of MC3T3-E1 cell line cultured in vitro. Results suggest that all of the glucoses mentioned above promoted the proliferation of osteoblast, and various concentrations have different effects： the proliferation was remarkable when the concentration of GLC, NAG, COS, CM-COS was 100 , 100, 500, 500 μg/mL ,respectively. Furthermore we choose the glucosamine as the material and study the effect on the bone strength in ovariectomized rats. The results showed that the middle does of glucosamine can significantly increase the hone strength of femur in ovariectomized rats.展开更多
Previous studies have demonstrated that deacetyl chitin conduit nerve bridging or electrical stimulation can effectively promote the regeneration of the injured peripheral nerve. We hypoth-esized that the combination ...Previous studies have demonstrated that deacetyl chitin conduit nerve bridging or electrical stimulation can effectively promote the regeneration of the injured peripheral nerve. We hypoth-esized that the combination of these two approaches could result in enhanced regeneration. Rats with right sciatic nerve injury were subjected to deacetyl chitin conduit bridging combined with electrical stimulation （0.1 ms, 3 V, 20 Hz, for 1 hour）. At 6 and 12 weeks after treatment, nerve conduction velocity, myelinated axon number, ifber diameter, axon diameter and the thickness of the myelin sheath in the stimulation group were better than in the non-stimulation group. The results indicate that deacetyl chitin conduit bridging combined with temporary electrical stimu-lation can promote peripheral nerve repair.展开更多
Twenty-six novel benzoylphenylurea chitin inhibitor derivatives have been synthesized in over 30~50% yield from chlorothalonil 1 via sequential fluorine exchange, aminolysis, hydrolysis, decarboxylation and acylation ...Twenty-six novel benzoylphenylurea chitin inhibitor derivatives have been synthesized in over 30~50% yield from chlorothalonil 1 via sequential fluorine exchange, aminolysis, hydrolysis, decarboxylation and acylation reactions.展开更多
Although autologous nerve transplantation is the gold standard for treating peripheral nerve defects,it has many clinical limitations.As an alternative,various tissue-engineered nerve grafts have been developed to sub...Although autologous nerve transplantation is the gold standard for treating peripheral nerve defects,it has many clinical limitations.As an alternative,various tissue-engineered nerve grafts have been developed to substitute for autologous nerves.In this study,a novel nerve graft composed of chitin scaffolds and a small autologous nerve was used to repair sciatic nerve defects in rats.The novel nerve graft greatly facilitated regeneration of the sciatic nerve and myelin sheath,reduced atrophy of the target muscle,and effectively restored neurological function.When the epineurium of the small autogenous nerve was removed,the degree of nerve regeneration was similar to that which occurs after autogenous nerve transplantation.These findings suggest that our novel nerve graft might eventually be a new option for the construction of tissue-engineered nerve scaffolds.The study was approved by the Research Ethics Committee of Peking University People's Hospital(approval No.2019 PHE27)on October 18,2019.展开更多
The adsorption properties of chitin adsorbent from mycelium of fermentation industries for the removal of heavy metal ions were studied. The result shows that the chitin adsorbent has high adsorption capacity for many...The adsorption properties of chitin adsorbent from mycelium of fermentation industries for the removal of heavy metal ions were studied. The result shows that the chitin adsorbent has high adsorption capacity for many heavy metal ions and Ni2+ in citric acid. The influence of pH was significant:When pH is higher than 4.0, the high adsorption capacity is obtained,otherwise H+ ion inhibits the adsorption of heavy metal ions. The comparison of the chitin adsorbent with some other commercial adsorbents was made, in which that the adsorption behaviorchitin adsorbent is close to that of commercial cation exchange adsorbents, and its cost is much lower than those commercial adsorbents.展开更多
Chitin was first discovered by its name from the Greek word“chiton”,which means“mail coat”.It is indeed a polysaccharide made up of naturally occurring acetyl-D-glucosamine monomers.Hatchett was the first research...Chitin was first discovered by its name from the Greek word“chiton”,which means“mail coat”.It is indeed a polysaccharide made up of naturally occurring acetyl-D-glucosamine monomers.Hatchett was the first researcher who extracted chitin from the shells of mollusks(crabs and lobsters),prawns,and crayfish in 1799.Later in 1811,Henri Braconnot discovered chitin in the cell walls of mushrooms and called it“fungine”.Chitin and chitosan are abundant in the biosphere as essential components of many organisms’exoskeletons and as by-products of the global seafood industry.The biopolymer must be deacetylated before chitosan can be produced.It can also be extracted using microbes in a biological extraction procedure.The development of products that take advantage of the bioactivities of the existing primary commercial source of chitin(crustacean)has lagged expectations.Also,the disadvantages of the present commercial source such as seasonality and competition for other uses among others has been one of the driving forces towards seeking alternative sources of chitin and chitosan in nature.This review highlights some of the efforts made by environmental scholars to locate possible commercial sources of chitin and chitosan in nature over time.展开更多
Objective: To investigate the cytotoxicity and cytocompatibility of chitin fiber reinforced polycaprolactone composite in vitro in order to provide useful scientific basis for clinical application. Methods: Cell morph...Objective: To investigate the cytotoxicity and cytocompatibility of chitin fiber reinforced polycaprolactone composite in vitro in order to provide useful scientific basis for clinical application. Methods: Cell morphology observation, MTT and DNA assay were used to evaluate the influence of the composite on the morphology, growth and proliferation of cultured L-929 cells. Results: The composite did not impair the morphology of cultured cells in vitro. MTT and DNA assay demonstrated that the growth and proliferation of the cultured cells were not significantly inhibited by the composite. Conclusion : The composites have fine cytocompatibility and are safe for clinical use of reconstruction of chest wall defects.展开更多
Chitin powder and chitin-aerogel were prepared from shrimp wastes and used to uptake Y^(3+)from aqueous solutions and concentrate this rare earth element from phosphogypsum(PG).Chitin aerogel displays a specific surfa...Chitin powder and chitin-aerogel were prepared from shrimp wastes and used to uptake Y^(3+)from aqueous solutions and concentrate this rare earth element from phosphogypsum(PG).Chitin aerogel displays a specific surface area of 945 m^(2)/g,while chitin powder is 3.6 m^(2)/g,which largely influences its adsorption ability.Regarding the adsorption in synthetic solutions,the effect of pH on Y^(3+)removal is strong for chitin powder adsorbent.In contrast,no big pH influence was detected for chitin aerogel.Electrostatic interactions and chelation can highlight the proposed mechanism of Y^(3+)on chitin adsorbents for the powder and aerogel.Furthermore,in addition to these interactions,pore filling/pore diffusion is the main mechanism of Y^(3+)removal in the chitin aerogel.Chitin aerogel is efficient in concentrating 8 times the Y^(3+)from PG,a very complex matrix.The complex chitin aerogel-Y^(3+)can be a secondary source of rare earth elements for other applications.展开更多
基金supported by the National Key Research and Development Program of China (No. 2022YFD1700200)the National Natural Science Foundation of China (Nos. 32161133010, 3230170969)+1 种基金the Innovation Program of Chinese Academy of Agricultural Sciences, the Shenzhen Science and Technology Program (No. KQTD20180411143628272)the Special Funds for Science Technology Innovation and Industrial Development of Shenzhen Dapeng New District (No. PT202101–02)。
文摘Chitin is an abundant aminopolysaccharide found in insect pests and phytopathogenic microorganisms but absent in higher plants and vertebrates. It is crucial for mitigating threats posed by chitin-containing organisms to human health, food safety, and agriculture. Therefore, targeting the chitin biosynthesisassociated bioprocess holds a promise for developing human-safe and eco-friendly antifungal agents or pesticides. Chitin biosynthesis requires chitin synthase and associated factors, which are involved in the modification, regulation, organization or turnover of chitin during its biosynthesis. A number of enzymes such as chitinases, hexosaminidases, chitin deacetylases are closely related and therefore are promising targets for designing novel agrochemicals that target at chitin biosynthesis. This review summarizes the advances in understanding chitin biology over the past decade by our research group and collaborates,specifically regarding essential proteins linked to chitin biosynthesis that can be exploited as promising pesticide targets. Examples of small bioactive molecules that against the activity of these targets are given.
基金supported by the National Natural Science Foundation of China(32161133010)the National Key Research and Development Program of China(2022YFD1700200)+2 种基金the Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CSCB-202302)the Shenzhen Science and Technology Program,China(KQTD20180411143628272)the Special Funds for Science Technology Innovation and Industrial Development of Shenzhen Dapeng New District,China(PT202101-02).
文摘Chitin is an abundant natural biopolymer that plays a crucial role in insect growth and development as a fundamental structural component of the exoskeleton.The membrane-integralβ-glycosyltransferase,chitin synthase,has been identified as the central component in chitin biosynthesis.However,the precise roles of other proteins in facilitating chitin synthase in chitin biosynthesis remain unclear.In this study,we employed split-ubiquitin membrane yeast two-hybrid(MYTH)and pull-down assays to demonstrate the physical interaction between Twinstar(Tsr),a small molecular protein in the actin-depolymerizing factor ADF/Cofilin protein family,and chitin synthase Krotzkopf verkehrt(Kkv)in Drosophila melanogaster in vitro.The RNA interference(RNAi)-mediated global knockdown of Tsr in D.melanogaster resulted in larval lethality.Furthermore,targeted suppression of Tsr in the tracheal and epidermal tissues also led to larval mortality,while knocking down Tsr in the wing tissues led to wrinkled wings.Additionally,silencing Tsr not only reduced the chitin content in the first longitudinal vein of the wings but also led to the absence of the chitin lamellar structure.To validate the functional conservation of Tsr in other insect orders,the two agricultural pests Ostrinia furnacalis and Tribolium castaneum,representing lepidoptera and coleoptera insects,respectively,were investigated.Knockdown experiments targeting the Drosophila Tsr orthologues OfTsr in O.furnacalis and TcTsr in T.castaneum produced abnormal larvae during molting or pupation in O.furnacalis and lethality in T.castaneum.Our findings not only improve ourknowledge of the chitin biosynthesis machinery in insect cuticles but also provide new potential targets for the control of major agricultural pests.
基金supported by the S&T Program of Hebei,China(23567601H)the Hebei Provincial Central Leading Local Science and Technology Development Fund Project,China(236Z6508G)+1 种基金the Basic Research Funds for Provincial Universities in Hebei Province,China(KY2022037 and KY2021042)the Natural Science Foundation of Hebei Province,China(C2023204100 and C2021204136)。
文摘LysM proteins contain the lysin domain(LysM),bind chitin and are found in various organisms including fungi.In phytopathogenic fungi,certain LysM proteins act as effectors to inhibit host immunity,thus increasing fungal virulence.However,our understanding of the LysM protein family in Setosphaeria turcica is limited.In this study,eight StLysM genes are identified and designated as StLysM1 to StLysM8.The analysis of sequence features indicates that five proteins(StLysM1,StLysM2,StLysM5,StLysM6,and StLysM7)are potential effectors.Phylogenetic analysis suggests that the StLysMs are divided into fungal/bacterial and fungus-specific subclasses.Domain architecture analysis reveals that the five StLysM effectors exclusively harbor the LysM domain,whereas the other three StLysM proteins contain additional functional domains.Sequence conservation analysis shows that the fungal-specific LysM domain sequences share the ^(8)GDxTC^(12) and ^(29)WNP^(31) motifs as well as three highly conserved cysteine residues.Conversely,the LysM domain sequences from the bacterial/fungal branch have few conserved sites.Moreover,expression profiling analysis shows that the StLysM1 gene is significantly upregulated during the infection of maize.Yeast secretion assays and transient expression experiments demonstrate that StLysM1 is a secreted protein that can suppress BAX/INF1-induced programmed cell death in Nicotiana benthamiana.Further functional analysis suggests that St Lys M1 cannot interact with itself but it can bind chitin.The transient expression of StLysM1 inhibits the chitin-triggered plant immune response,increasing susceptibility to the phytopathogenic fungus Botrytis cinerea in N.benthamiana.This study reveals that the S.turcica LySM protein family consists of eight members,highlighting the significance of StLysM1 as a vital effector in regulating plant immunity.The results provide insight into StLysMs and establish a foundation for understanding the roles of StLysM proteins in the pathogenic process of S.turcica.
基金support of the National Natural Science Foundation of China(22408032)the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202000826 and KJQN202300836)+2 种基金Research Start-up Funding project of Chongqing Technology and Business University(1856011)Science and Technology Project of Chongqing Technology and Business University(2152027)Graduate Innovative Research Project from Chongqing Technology and Business University(yjscxx2024-284-29).
文摘In the last decade,shell biorefinery,a novel concept referring to the extraction of the main components of crustacean shells and the transformation of each component into valuable products,was proposed and has attracted increasing attentions.Chitin is one of main components of crustacean shells.Owing to the bio-fixed nitrogen element,chitin biomass has been regarded as a good candidate to produce nitrogen-containing chemicals.Among these,3-acetamido-5-acetylfuran(3A5AF)is an interesting furanic compound derived from the hydrolysis and sequential dehydration of chitin.Similar to cellulose-derived platform chemical 5-hydromethylfurfural(HMF),3A5AF is an emerging platform compound and also can be converted into various useful chemicals by oxidation,reduction,hydrolysis,substitution,and so on.This review showcases the recent advances in the synthesis of 3A5AF from chitin and N-acetyl glucosamine(NAG)employing various catalytic systems.The conversion of 3A5AF into valuable compounds was introduced then.There are still some challenges in this area,for example,the rational design of green and efficient catalytic systems for the synthesis of 3A5AF and its derivatives.The outlooks also were discussed at the end of the review.
文摘Chitin,distinguished by its nitrogen-rich acetamido and amino groups,imparts a distinctive cationic nature,enabling chitin to have indispensable features in various applications.Despite its significant promise in the textile industry,particularly for sustainable and functional fabric applications,the practical utilization of chitin fibers remains constrained by insufficient mechanical strength.The degree of deacetylation(DD),a key molecular-level structural determinant,has not been adequately addressed in previous studies despite its critical role in influencing chitin properties across multiple scales.In this study,a deacetylation-mediated design strategy was used to achieve enhanced mechanical performance coupled with multifunctional efficacy using an aqueous KOH/urea solution dissolution system.We prepared a series of deacetylated chitins with different DD values and systematically studied the effect of deacetylation on the multiple-scale structure of regenerated fibers,such as intermolecular interactions and chain orientation at the molecular level,and the aggregation behavior of chitin nanofibers within the gel-state and dried fibers at the micro/nano scale.To achieve an enhanced mechanical performance coupled with multifunctional efficacy by relying on an aqueous KOH/urea solution dissolution system.Moreover,deacetylation enhances intermolecular interactions,resulting in densified internal structures and improved fiber orientation.Concomitantly,it augmented the antimicrobial functionality of the fibers.This deacetylation-mediated design strategy provides a deeper understanding of the structure and properties of regenerated chitin and advances the utility of chitin in strong and sustainable fibers.
基金Supported by the National Natural Science Foundation of China(No.42076126)the Shandong Key R&D Plan+2 种基金Major Scientific and Technological Innovation Project(No.2022CXGC020413)the Natural Science Foundation of Shandong Province(Nos.ZR2020MD072,ZR2021QD014)the Liaoning Provincial Natural Science Foundation:Joint Open Fund of the State Key Laboratory for the Creation and Development of New Pesticides(No.2022-KF-25-03)。
文摘The conversion process of chitin,one of the abundant biomass resources on the earth,not only follows the principles of green chemistry,but also has significant value in industrial applications.However,it is a great challenge to directly convert insoluble and rigid structured chitin to 5-hydroxymethylfurfural(HMF).To address this issue,we developed a green conversion process combining pretreatment and catalytic system.Chitin was first pretreated by hexafluoro isopropanol(HFIP),which somewhat disrupted the hydrogen bonding network within the chitin structure.Subsequently,formic acid(FA)and silicotungstic acid(STA)synergistically catalyzed the conversion to HMF in a biphasic system of 2-methyltetrahydrofuran(2-Me-THF)/H2O,and high yields(40.2%)HMF was obtained under the optimism conditions.The product distribution was analyzed by HPLC-MS and the co-catalysis of FA with STA was evidenced.A dual-function catalytic system with both Lewis and Br?nsted acids was created,the catalytic system that significantly improved the efficiency of complex tandem catalytic reactions with chitin.Based on the experimental results,a possible pathway for chitin conversion was deduced,providing a new catalytic idea for the efficient conversion of chitin to HMF.
基金Supported by Science and Technology Support Project of Guangdong Academy of Agricultural Science and Technology(07-Supporting-04)Agricultural Research Projects in Guangdong Province (2007A0201000043)Earmarked Fund for Modern Agro-Industry Technology Research System of China~~
文摘[Objective] The aim of this study was to optimize the conditions of chitinase-produce strains.[Method] A kind of screened chitinase-produce strain G-254 was habituated cultured,and then the single factor experiment was carried out to explore the effects of different carbon source,nitrogen source and inorganic salt on the activity of produced chitinase;the response surface test was used to determine the optimal conditions for chitinase production.[Result] The optimal conditions for chitinase production were：8% of glucose,5% of beef extract and 0.07% of MgSO4,and the activity of chitinase reached the maximal value（6.86 U）under these conditions.[Conclusion] The study improved the activity of chitinase produced by strain G-254 and provided good foundation for industrial production.
基金supported by China Agriculture Research System (No. CARS-48)the Major Special Science and Technology Projects in Shandong Province (No. 2016 YYSP016)+2 种基金the Ningbo Science and Technology Projects (No. 2017C110006)the Shandong Provincial Natural Science Foundation, China (No. ZR2015CQ021)the Fundamental Research Funds for the Central Universities (No. 201564018)
文摘The industrial processing of shrimp produces massive quantities of solid waste that is a notable source of animal protein, chitin, carotenoids, and other bioactive compounds that are not appropriately utilized. In the present study, chitin and protein extraction from shrimp head with autolysis and fermentation using Bacillus licheniformis were investigated. The results showed that when shrimp heads were autolyzed with a natural pH at 50℃ for 4 h, the total amino acid nitrogen in the supernatant was 5.01 mg mL^-1. Then, when a 50%(v/m) inoculum of the hydrolysate was incubated at 60℃ for 10 h, a deproteinization rate of 88.3% could be obtained. The fermented supernatant was processed into a dry protein powder, while the residues were demineralized by 10% citric acid for chitin. The recovered protein powder contained 5.5% moisture, 11.5% ash, and 66.7% protein, while the chitin contained 3.5% moisture, 2.1% ash, and 3.1% protein. In addition, amino acids, minerals, heavy metals, the degree of acetylation, microstructure, and Fourier-transform infrared(FT-IR) spectroscopy results were analyzed. Furthermore, the statistics of the large scale trial after treatment with 20 kg of shrimp heads were analyzed. Thus, this work made the shrimp waste utilization environmentally sound and valuable.
基金This work was financially supported by the National Natural Science Foundation of China(No.21875170)The authors thank to the facility support of the Special Fund for the Development of Strategic Emerging Industries of Shenzhen City of China(Nos.JCYJ20180507184711069 and JCYJ20170818112409808)+1 种基金Fundamental Research Funds for the Central Universities(No.2042019kf0276)Wuhan Morning Light Plan of Youth Science and Technology(No.2017050304010312).
文摘Chitin is an abundant natural nitrogen-containing biopolymer with great application potential in materials,environment,energy,and health.However,the structure characteristics and processing technologies have required intense research in related applications.In particular,there have been great efforts to developing solvents for chitin,and the results s0 far are quite encouraging.This review summarizes the main solvent systems used for chitin,namely the aqueous solvent systems(mineral acids,inorganic salt aqueous solutions,alkali aqueous solutions)and non aqueous ones(LiCl-dimethylacetamide solvents,CaCl22H2O saturated methanol,ionic liquids,deep eutectic solvents,and protic organic solvents).The solvent properties,dissolution methods,and solution properties are discussed in detail.Special attention is paid to the dissolution mechanism in each system.This review can provide a reference for understanding the dissolution behavior of chitin and finding suitable solvents for it.
基金Supported by the Key Technologies Research andDevelopment Programof the Tenth five-year Plan of the Nation Scien-tific and Technological Development .(2001BA708B04-07)
文摘This study intends to examine the effects of different concentrations of four kinds of degradations of chitin： glucosamine （GLC）, N-acetyl-D-glucosamine （NAG）, chitooligosaccharide（COS）, CM-chitooligosaccharide （CM-COS）—on the proliferation of MC3T3-E1 cell line cultured in vitro. Results suggest that all of the glucoses mentioned above promoted the proliferation of osteoblast, and various concentrations have different effects： the proliferation was remarkable when the concentration of GLC, NAG, COS, CM-COS was 100 , 100, 500, 500 μg/mL ,respectively. Furthermore we choose the glucosamine as the material and study the effect on the bone strength in ovariectomized rats. The results showed that the middle does of glucosamine can significantly increase the hone strength of femur in ovariectomized rats.
基金funded by National Program on Key Basic Research Project of China(973 Program),No.2014CB542200the National Natural Science Foundation of China,No.31171150,31271284,30801169+2 种基金the Chinese Educational Ministry New Century Excellent Talent Support Project,No.BMU20110270the Beijing City Science&Technology New Star Classification,No.2008A010the Ministry of Education New Teachers of Institutions of Higher Learning Doctoral Fund,No.20070001780
文摘Previous studies have demonstrated that deacetyl chitin conduit nerve bridging or electrical stimulation can effectively promote the regeneration of the injured peripheral nerve. We hypoth-esized that the combination of these two approaches could result in enhanced regeneration. Rats with right sciatic nerve injury were subjected to deacetyl chitin conduit bridging combined with electrical stimulation （0.1 ms, 3 V, 20 Hz, for 1 hour）. At 6 and 12 weeks after treatment, nerve conduction velocity, myelinated axon number, ifber diameter, axon diameter and the thickness of the myelin sheath in the stimulation group were better than in the non-stimulation group. The results indicate that deacetyl chitin conduit bridging combined with temporary electrical stimu-lation can promote peripheral nerve repair.
基金support of the Natural Science Foundation of Yunnan Province(1999B0005M)the Open Foundation of State Key Laboratory of Elemento-Organic Chemistry,Nankai University
文摘Twenty-six novel benzoylphenylurea chitin inhibitor derivatives have been synthesized in over 30~50% yield from chlorothalonil 1 via sequential fluorine exchange, aminolysis, hydrolysis, decarboxylation and acylation reactions.
基金supported by the National Natural Science Foundation of China,Nos.31571236(to YHK),81971177(to BGJ)Key Laboratory of Trauma and Neural Regeneration(Peking University)of the Ministry of Education of China,No.BMU2020XY005-03(to BGJ)+2 种基金the National Key Research and Development Program of China,No.2016YFC1101604(to DYZ)the Ministry of Education Innovation Program of China,No.IRT_16R01(to BGJ)China Postdoctoral Science Foundation-Funded Project,No.2019M664007(to ZYL)。
文摘Although autologous nerve transplantation is the gold standard for treating peripheral nerve defects,it has many clinical limitations.As an alternative,various tissue-engineered nerve grafts have been developed to substitute for autologous nerves.In this study,a novel nerve graft composed of chitin scaffolds and a small autologous nerve was used to repair sciatic nerve defects in rats.The novel nerve graft greatly facilitated regeneration of the sciatic nerve and myelin sheath,reduced atrophy of the target muscle,and effectively restored neurological function.When the epineurium of the small autogenous nerve was removed,the degree of nerve regeneration was similar to that which occurs after autogenous nerve transplantation.These findings suggest that our novel nerve graft might eventually be a new option for the construction of tissue-engineered nerve scaffolds.The study was approved by the Research Ethics Committee of Peking University People's Hospital(approval No.2019 PHE27)on October 18,2019.
基金Supported by National Natural Science Foundation of China(No. 29976004 and 20136020) and Fok Ying-tung Education Foundation(No. 71067).
文摘The adsorption properties of chitin adsorbent from mycelium of fermentation industries for the removal of heavy metal ions were studied. The result shows that the chitin adsorbent has high adsorption capacity for many heavy metal ions and Ni2+ in citric acid. The influence of pH was significant:When pH is higher than 4.0, the high adsorption capacity is obtained,otherwise H+ ion inhibits the adsorption of heavy metal ions. The comparison of the chitin adsorbent with some other commercial adsorbents was made, in which that the adsorption behaviorchitin adsorbent is close to that of commercial cation exchange adsorbents, and its cost is much lower than those commercial adsorbents.
基金This study is funded by the Long Term Research Grant Scheme(LRGS/1/2018/USM/01/1/1)(LRGS/2018/USM-UKM/EWS/01)granted by Ministry of Higher Education Malaysia for funding this research project.
文摘Chitin was first discovered by its name from the Greek word“chiton”,which means“mail coat”.It is indeed a polysaccharide made up of naturally occurring acetyl-D-glucosamine monomers.Hatchett was the first researcher who extracted chitin from the shells of mollusks(crabs and lobsters),prawns,and crayfish in 1799.Later in 1811,Henri Braconnot discovered chitin in the cell walls of mushrooms and called it“fungine”.Chitin and chitosan are abundant in the biosphere as essential components of many organisms’exoskeletons and as by-products of the global seafood industry.The biopolymer must be deacetylated before chitosan can be produced.It can also be extracted using microbes in a biological extraction procedure.The development of products that take advantage of the bioactivities of the existing primary commercial source of chitin(crustacean)has lagged expectations.Also,the disadvantages of the present commercial source such as seasonality and competition for other uses among others has been one of the driving forces towards seeking alternative sources of chitin and chitosan in nature.This review highlights some of the efforts made by environmental scholars to locate possible commercial sources of chitin and chitosan in nature over time.
基金Supported by the Sci & Tech Development Foundation of Shang-hai (No. 024419076)
文摘Objective: To investigate the cytotoxicity and cytocompatibility of chitin fiber reinforced polycaprolactone composite in vitro in order to provide useful scientific basis for clinical application. Methods: Cell morphology observation, MTT and DNA assay were used to evaluate the influence of the composite on the morphology, growth and proliferation of cultured L-929 cells. Results: The composite did not impair the morphology of cultured cells in vitro. MTT and DNA assay demonstrated that the growth and proliferation of the cultured cells were not significantly inhibited by the composite. Conclusion : The composites have fine cytocompatibility and are safe for clinical use of reconstruction of chest wall defects.
基金Project supported by Brazilian National Council for Scientific and Technological Development/CNPq(405982/2022-4,303992/2021-2)Coordination for the Improvement of Higher Education Personnel/CAPES(CAPESPRINT Program)。
文摘Chitin powder and chitin-aerogel were prepared from shrimp wastes and used to uptake Y^(3+)from aqueous solutions and concentrate this rare earth element from phosphogypsum(PG).Chitin aerogel displays a specific surface area of 945 m^(2)/g,while chitin powder is 3.6 m^(2)/g,which largely influences its adsorption ability.Regarding the adsorption in synthetic solutions,the effect of pH on Y^(3+)removal is strong for chitin powder adsorbent.In contrast,no big pH influence was detected for chitin aerogel.Electrostatic interactions and chelation can highlight the proposed mechanism of Y^(3+)on chitin adsorbents for the powder and aerogel.Furthermore,in addition to these interactions,pore filling/pore diffusion is the main mechanism of Y^(3+)removal in the chitin aerogel.Chitin aerogel is efficient in concentrating 8 times the Y^(3+)from PG,a very complex matrix.The complex chitin aerogel-Y^(3+)can be a secondary source of rare earth elements for other applications.
