Short-Chain Chitin Oligomers: Promoters of Plant Growth

PubMed Central

Winkler, Alexander J.; Dominguez-Nuñez, Jose Alfonso; Aranaz, Inmaculada; Poza-Carrión, César; Ramonell, Katrina; Somerville, Shauna; Berrocal-Lobo, Marta

2017-01-01

Chitin is the second most abundant biopolymer in nature after cellulose, and it forms an integral part of insect exoskeletons, crustacean shells, krill and the cell walls of fungal spores, where it is present as a high-molecular-weight molecule. In this study, we showed that a chitin oligosaccharide of lower molecular weight (tetramer) induced genes in Arabidopsis that are principally related to vegetative growth, development and carbon and nitrogen metabolism. Based on plant responses to this chitin tetramer, a low-molecular-weight chitin mix (CHL) enriched to 92% with dimers (2mer), trimers (3mer) and tetramers (4mer) was produced for potential use in biotechnological processes. Compared with untreated plants, CHL-treated plants had increased in vitro fresh weight (10%), radicle length (25%) and total carbon and nitrogen content (6% and 8%, respectively). Our data show that low-molecular-weight forms of chitin might play a role in nature as bio-stimulators of plant growth, and they are also a known direct source of carbon and nitrogen for soil biomass. The biochemical properties of the CHL mix might make it useful as a non-contaminating bio-stimulant of plant growth and a soil restorer for greenhouses and fields. PMID:28212295

Short-Chain Chitin Oligomers: Promoters of Plant Growth.

PubMed

Winkler, Alexander J; Dominguez-Nuñez, Jose Alfonso; Aranaz, Inmaculada; Poza-Carrión, César; Ramonell, Katrina; Somerville, Shauna; Berrocal-Lobo, Marta

2017-02-15

Chitin is the second most abundant biopolymer in nature after cellulose, and it forms an integral part of insect exoskeletons, crustacean shells, krill and the cell walls of fungal spores, where it is present as a high-molecular-weight molecule. In this study, we showed that a chitin oligosaccharide of lower molecular weight (tetramer) induced genes in Arabidopsis that are principally related to vegetative growth, development and carbon and nitrogen metabolism. Based on plant responses to this chitin tetramer, a low-molecular-weight chitin mix (CHL) enriched to 92% with dimers (2mer), trimers (3mer) and tetramers (4mer) was produced for potential use in biotechnological processes. Compared with untreated plants, CHL-treated plants had increased in vitro fresh weight (10%), radicle length (25%) and total carbon and nitrogen content (6% and 8%, respectively). Our data show that low-molecular-weight forms of chitin might play a role in nature as bio-stimulators of plant growth, and they are also a known direct source of carbon and nitrogen for soil biomass. The biochemical properties of the CHL mix might make it useful as a non-contaminating bio-stimulant of plant growth and a soil restorer for greenhouses and fields.

KRE5 Suppression Induces Cell Wall Stress and Alternative ER Stress Response Required for Maintaining Cell Wall Integrity in Candida glabrata

PubMed Central

Sasaki, Masato; Ito, Fumie; Aoyama, Toshio; Sato-Okamoto, Michiyo; Takahashi-Nakaguchi, Azusa; Chibana, Hiroji; Shibata, Nobuyuki

2016-01-01

The maintenance of cell wall integrity in fungi is required for normal cell growth, division, hyphae formation, and antifungal tolerance. We observed that endoplasmic reticulum stress regulated cell wall integrity in Candida glabrata, which possesses uniquely evolved mechanisms for unfolded protein response mechanisms. Tetracycline-mediated suppression of KRE5, which encodes a predicted UDP-glucose:glycoprotein glucosyltransferase localized in the endoplasmic reticulum, significantly increased cell wall chitin content and decreased cell wall β-1,6-glucan content. KRE5 repression induced endoplasmic reticulum stress-related gene expression and MAP kinase pathway activation, including Slt2p and Hog1p phosphorylation, through the cell wall integrity signaling pathway. Moreover, the calcineurin pathway negatively regulated cell wall integrity, but not the reduction of β-1,6-glucan content. These results indicate that KRE5 is required for maintaining both endoplasmic reticulum homeostasis and cell wall integrity, and that the calcineurin pathway acts as a regulator of chitin-glucan balance in the cell wall and as an alternative mediator of endoplasmic reticulum stress in C. glabrata. PMID:27548283

Large-Scale Phylogenetic Classification of Fungal Chitin Synthases and Identification of a Putative Cell-Wall Metabolism Gene Cluster in Aspergillus Genomes

PubMed Central

Pacheco-Arjona, Jose Ramon; Ramirez-Prado, Jorge Humberto

2014-01-01

The cell wall is a protective and versatile structure distributed in all fungi. The component responsible for its rigidity is chitin, a product of chitin synthase (Chsp) enzymes. There are seven classes of chitin synthase genes (CHS) and the amount and type encoded in fungal genomes varies considerably from one species to another. Previous Chsp sequence analyses focused on their study as individual units, regardless of genomic context. The identification of blocks of conserved genes between genomes can provide important clues about the interactions and localization of chitin synthases. On the present study, we carried out an in silico search of all putative Chsp encoded in 54 full fungal genomes, encompassing 21 orders from five phyla. Phylogenetic studies of these Chsp were able to confidently classify 347 out of the 369 Chsp identified (94%). Patterns in the distribution of Chsp related to taxonomy were identified, the most prominent being related to the type of fungal growth. More importantly, a synteny analysis for genomic blocks centered on class IV Chsp (the most abundant and widely distributed Chsp class) identified a putative cell wall metabolism gene cluster in members of the genus Aspergillus, the first such association reported for any fungal genome. PMID:25148134

Heterologous Expression of an Entamoeba histolytica Chitin Synthase in Saccharomyces cerevisiae

PubMed Central

Van Dellen, Katrina L.; Bulik, Dorota A.; Specht, Charles A.; Robbins, Phillips W.; Samuelson, John C.

2006-01-01

Chitin in the cyst wall of Entamoeba histolytica is made by two chitin synthases (Chs), one of which is unique (EhCHS-1) and one of which resembles those of insects and nematodes (EhCHS-2). EhCHS-1 is deposited chitin in the lateral wall of transformed Saccharomyces cerevisiae Chs mutants, independent of accessory proteins (Chs4p to Chs7p) required by yeast Chs3p. PMID:16400183

Heterologous expression of an Entamoeba histolytica chitin synthase in Saccharomyces cerevisiae.

PubMed

Van Dellen, Katrina L; Bulik, Dorota A; Specht, Charles A; Robbins, Phillips W; Samuelson, John C

2006-01-01

Chitin in the cyst wall of Entamoeba histolytica is made by two chitin synthases (Chs), one of which is unique (EhCHS-1) and one of which resembles those of insects and nematodes (EhCHS-2). EhCHS-1 is deposited chitin in the lateral wall of transformed Saccharomyces cerevisiae Chs mutants, independent of accessory proteins (Chs4p to Chs7p) required by yeast Chs3p.

Aspergillus Cell Wall Chitin Induces Anti- and Proinflammatory Cytokines in Human PBMCs via the Fc-γ Receptor/Syk/PI3K Pathway.

PubMed

Becker, K L; Aimanianda, V; Wang, X; Gresnigt, M S; Ammerdorffer, A; Jacobs, C W; Gazendam, R P; Joosten, L A B; Netea, M G; Latgé, J P; van de Veerdonk, F L

2016-05-31

Chitin is an important cell wall component of Aspergillus fumigatus conidia, of which hundreds are inhaled on a daily basis. Previous studies have shown that chitin has both anti- and proinflammatory properties; however the exact mechanisms determining the inflammatory signature of chitin are poorly understood, especially in human immune cells. Human peripheral blood mononuclear cells were isolated from healthy volunteers and stimulated with chitin from Aspergillus fumigatus Transcription and production of the proinflammatory cytokine interleukin-1β (IL-1β) and the anti-inflammatory cytokine IL-1 receptor antagonist (IL-1Ra) were measured from the cell culture supernatant by quantitative PCR (qPCR) or enzyme-linked immunosorbent assay (ELISA), respectively. Chitin induced an anti-inflammatory signature characterized by the production of IL-1Ra in the presence of human serum, which was abrogated in immunoglobulin-depleted serum. Fc-γ-receptor-dependent recognition and phagocytosis of IgG-opsonized chitin was identified as a novel IL-1Ra-inducing mechanism by chitin. IL-1Ra production induced by chitin was dependent on Syk kinase and phosphatidylinositol 3-kinase (PI3K) activation. In contrast, costimulation of chitin with the pattern recognition receptor (PRR) ligands lipopolysaccharide, Pam3Cys, or muramyl dipeptide, but not β-glucan, had synergistic effects on the induction of proinflammatory cytokines by human peripheral blood mononuclear cells (PBMCs). In conclusion, chitin can have both pro- and anti-inflammatory properties, depending on the presence of pathogen-associated molecular patterns and immunoglobulins, thus explaining the various inflammatory signatures reported for chitin. Invasive aspergillosis and allergic aspergillosis are increasing health care problems. Patients get infected by inhalation of the airborne spores of Aspergillus fumigatus A profound knowledge of how Aspergillus and its cell wall components are recognized by the host cell and

Recognition and Blocking of Innate Immunity Cells by Candida albicans Chitin ▿ †

PubMed Central

Mora-Montes, Héctor M.; Netea, Mihai G.; Ferwerda, Gerben; Lenardon, Megan D.; Brown, Gordon D.; Mistry, Anita R.; Kullberg, Bart Jan; O'Callaghan, Chris A.; Sheth, Chirag C.; Odds, Frank C.; Brown, Alistair J. P.; Munro, Carol A.; Gow, Neil A. R.

2011-01-01

Chitin is a skeletal cell wall polysaccharide of the inner cell wall of fungal pathogens. As yet, little about its role during fungus-host immune cell interactions is known. We show here that ultrapurified chitin from Candida albicans cell walls did not stimulate cytokine production directly but blocked the recognition of C. albicans by human peripheral blood mononuclear cells (PBMCs) and murine macrophages, leading to significant reductions in cytokine production. Chitin did not affect the induction of cytokines stimulated by bacterial cells or lipopolysaccharide (LPS), indicating that blocking was not due to steric masking of specific receptors. Toll-like receptor 2 (TLR2), TLR4, and Mincle (the macrophage-inducible C-type lectin) were not required for interactions with chitin. Dectin-1 was required for immune blocking but did not bind chitin directly. Cytokine stimulation was significantly reduced upon stimulation of PBMCs with heat-killed chitin-deficient C. albicans cells but not with live cells. Therefore, chitin is normally not exposed to cells of the innate immune system but is capable of influencing immune recognition by blocking dectin-1-mediated engagement with fungal cell walls. PMID:21357722

Aspergillus Cell Wall Chitin Induces Anti- and Proinflammatory Cytokines in Human PBMCs via the Fc-γ Receptor/Syk/PI3K Pathway

PubMed Central

Becker, K. L.; Aimanianda, V.; Wang, X.; Gresnigt, M. S.; Ammerdorffer, A.; Jacobs, C. W.; Gazendam, R. P.; Joosten, L. A. B.; Netea, M. G.

2016-01-01

ABSTRACT Chitin is an important cell wall component of Aspergillus fumigatus conidia, of which hundreds are inhaled on a daily basis. Previous studies have shown that chitin has both anti- and proinflammatory properties; however the exact mechanisms determining the inflammatory signature of chitin are poorly understood, especially in human immune cells. Human peripheral blood mononuclear cells were isolated from healthy volunteers and stimulated with chitin from Aspergillus fumigatus. Transcription and production of the proinflammatory cytokine interleukin-1β (IL-1β) and the anti-inflammatory cytokine IL-1 receptor antagonist (IL-1Ra) were measured from the cell culture supernatant by quantitative PCR (qPCR) or enzyme-linked immunosorbent assay (ELISA), respectively. Chitin induced an anti-inflammatory signature characterized by the production of IL-1Ra in the presence of human serum, which was abrogated in immunoglobulin-depleted serum. Fc-γ-receptor-dependent recognition and phagocytosis of IgG-opsonized chitin was identified as a novel IL-1Ra-inducing mechanism by chitin. IL-1Ra production induced by chitin was dependent on Syk kinase and phosphatidylinositol 3-kinase (PI3K) activation. In contrast, costimulation of chitin with the pattern recognition receptor (PRR) ligands lipopolysaccharide, Pam3Cys, or muramyl dipeptide, but not β-glucan, had synergistic effects on the induction of proinflammatory cytokines by human peripheral blood mononuclear cells (PBMCs). In conclusion, chitin can have both pro- and anti-inflammatory properties, depending on the presence of pathogen-associated molecular patterns and immunoglobulins, thus explaining the various inflammatory signatures reported for chitin. PMID:27247234

Fungal Chitin Dampens Inflammation through IL-10 Induction Mediated by NOD2 and TLR9 Activation

PubMed Central

Wagener, Jeanette; Malireddi, R. K. Subbarao; Lenardon, Megan D.; Köberle, Martin; Vautier, Simon; MacCallum, Donna M.; Biedermann, Tilo; Schaller, Martin; Netea, Mihai G.; Kanneganti, Thirumala-Devi; Brown, Gordon D.; Brown, Alistair J. P.; Gow, Neil A. R.

2014-01-01

during fungal infection and restore immune balance after an infection has been cleared. By increasing the chitin content in the cell wall pathogenic fungi may influence the immune system in their favour, by down-regulating protective inflammatory immune responses. Furthermore, gene mutations and dysregulated enzyme activity in the described chitin recognition pathway are implicated in inflammatory conditions such as Crohn's Disease and asthma, highlighting the importance of the discovered mechanism in human health. PMID:24722226

Analysis of Chitin in Contaminated Fuels

DTIC Science & Technology

1975-09-01

medium (12) Glucosamine hydrochloride (Iml = 8.6 mg glucosamine ). Store frozen at -IOOC. 2. Procedure. a. Take at least 10 bottles (bottle dimensions are...DISCUSSION 6. Discussion 5 V CONCLUSIONS 7. Conclusions 5 :1IBLIOGRAPHY 7 APIYFNDIX - Analytical Procedure for the Determination of Chitin As Glucosamine 8...concentration of the aminosugar. Chitin, a polymer of glucosamine . is present in the cell wall of most fungi3 and, thus, if determined quantitatively serves to

Investigating chitin deacetylation and chitosan hydrolysis during vegetative growth in Magnaporthe oryzae

PubMed Central

Geoghegan, Ivey A.

2017-01-01

Summary Chitin deacetylation results in the formation of chitosan, a polymer of β1,4‐linked glucosamine. Chitosan is known to have important functions in the cell walls of a number of fungal species, but its role during hyphal growth has not yet been investigated. In this study, we have characterized the role of chitin deacetylation during vegetative hyphal growth in the filamentous phytopathogen Magnaporthe oryzae. We found that chitosan localizes to the septa and lateral cell walls of vegetative hyphae and identified 2 chitin deacetylases expressed during vegetative growth—CDA1 and CDA4. Deletion strains and fluorescent protein fusions demonstrated that CDA1 is necessary for chitin deacetylation in the septa and lateral cell walls of mature hyphae in colony interiors, whereas CDA4 deacetylates chitin in the hyphae at colony margins. However, although the Δcda1 strain was more resistant to cell wall hydrolysis, growth and pathogenic development were otherwise unaffected in the deletion strains. The role of chitosan hydrolysis was also investigated. A single gene encoding a putative chitosanase (CSN) was discovered in M. oryzae and found to be expressed during vegetative growth. However, chitosan localization, vegetative growth, and pathogenic development were unaffected in a CSN deletion strain, rendering the role of this enzyme unclear. PMID:28371146

A Glycosylphosphatidylinositol Anchor Is Required for Membrane Localization but Dispensable for Cell Wall Association of Chitin Deacetylase 2 in Cryptococcus neoformans

PubMed Central

Gilbert, Nicole M.; Baker, Lorina G.; Specht, Charles A.; Lodge, Jennifer K.

2012-01-01

ABSTRACT Cell wall proteins (CWPs) mediate important cellular processes in fungi, including adhesion, invasion, biofilm formation, and flocculation. The current model of fungal cell wall organization includes a major class of CWPs covalently bound to β-1,6-glucan via a remnant of a glycosylphosphatidylinositol (GPI) anchor. This model was established by studies of ascomycetes more than a decade ago, and relatively little work has been done with other fungi, although the presumption has been that proteins identified in the cell wall which contain a predicted GPI anchor are covalently linked to cell wall glucans. The pathogenic basidiomycete Cryptococcus neoformans encodes >50 putatively GPI-anchored proteins, some of which have been identified in the cell wall. One of these proteins is chitin deacetylase 2 (Cda2), an enzyme responsible for converting chitin to chitosan, a cell wall polymer recently established as a virulence factor for C. neoformans infection of mammalian hosts. Using a combination of biochemistry, molecular biology, and genetics, we show that Cda2 is GPI anchored to membranes but noncovalently associated with the cell wall by means independent of both its GPI anchor and β-1,6-glucan. We also show that Cda2 produces chitosan when localized to the plasma membrane, but association with the cell wall is not essential for this process, thereby providing insight into the mechanism of chitosan biosynthesis. These results increase our understanding of the surface of C. neoformans and provide models of cell walls likely applicable to other undercharacterized basidiomycete pathogenic fungi. PMID:22354955

An interactional network of genes involved in chitin synthesis in Saccharomyces cerevisiae.

PubMed

Lesage, Guillaume; Shapiro, Jesse; Specht, Charles A; Sdicu, Anne-Marie; Ménard, Patrice; Hussein, Shamiza; Tong, Amy Hin Yan; Boone, Charles; Bussey, Howard

2005-02-16

In S. cerevisiae the beta-1,4-linked N-acetylglucosamine polymer, chitin, is synthesized by a family of 3 specialized but interacting chitin synthases encoded by CHS1, CHS2 and CHS3. Chs2p makes chitin in the primary septum, while Chs3p makes chitin in the lateral cell wall and in the bud neck, and can partially compensate for the lack of Chs2p. Chs3p requires a pathway of Bni4p, Chs4p, Chs5p, Chs6p and Chs7p for its localization and activity. Chs1p is thought to have a septum repair function after cell separation. To further explore interactions in the chitin synthase family and to find processes buffering chitin synthesis, we compiled a genetic interaction network of genes showing synthetic interactions with CHS1, CHS3 and genes involved in Chs3p localization and function and made a phenotypic analysis of their mutants. Using deletion mutants in CHS1, CHS3, CHS4, CHS5, CHS6, CHS7 and BNI4 in a synthetic genetic array analysis we assembled a network of 316 interactions among 163 genes. The interaction network with CHS3, CHS4, CHS5, CHS6, CHS7 or BNI4 forms a dense neighborhood, with many genes functioning in cell wall assembly or polarized secretion. Chitin levels were altered in 54 of the mutants in individually deleted genes, indicating a functional relationship between them and chitin synthesis. 32 of these mutants triggered the chitin stress response, with elevated chitin levels and a dependence on CHS3. A large fraction of the CHS1-interaction set was distinct from that of the CHS3 network, indicating broad roles for Chs1p in buffering both Chs2p function and more global cell wall robustness. Based on their interaction patterns and chitin levels we group interacting mutants into functional categories. Genes interacting with CHS3 are involved in the amelioration of cell wall defects and in septum or bud neck chitin synthesis, and we newly assign a number of genes to these functions. Our genetic analysis of genes not interacting with CHS3 indicate expanded

An interactional network of genes involved in chitin synthesis in Saccharomyces cerevisiae

PubMed Central

Lesage, Guillaume; Shapiro, Jesse; Specht, Charles A; Sdicu, Anne-Marie; Ménard, Patrice; Hussein, Shamiza; Tong, Amy Hin Yan; Boone, Charles; Bussey, Howard

2005-01-01

Background In S. cerevisiae the β-1,4-linked N-acetylglucosamine polymer, chitin, is synthesized by a family of 3 specialized but interacting chitin synthases encoded by CHS1, CHS2 and CHS3. Chs2p makes chitin in the primary septum, while Chs3p makes chitin in the lateral cell wall and in the bud neck, and can partially compensate for the lack of Chs2p. Chs3p requires a pathway of Bni4p, Chs4p, Chs5p, Chs6p and Chs7p for its localization and activity. Chs1p is thought to have a septum repair function after cell separation. To further explore interactions in the chitin synthase family and to find processes buffering chitin synthesis, we compiled a genetic interaction network of genes showing synthetic interactions with CHS1, CHS3 and genes involved in Chs3p localization and function and made a phenotypic analysis of their mutants. Results Using deletion mutants in CHS1, CHS3, CHS4, CHS5, CHS6, CHS7 and BNI4 in a synthetic genetic array analysis we assembled a network of 316 interactions among 163 genes. The interaction network with CHS3, CHS4, CHS5, CHS6, CHS7 or BNI4 forms a dense neighborhood, with many genes functioning in cell wall assembly or polarized secretion. Chitin levels were altered in 54 of the mutants in individually deleted genes, indicating a functional relationship between them and chitin synthesis. 32 of these mutants triggered the chitin stress response, with elevated chitin levels and a dependence on CHS3. A large fraction of the CHS1-interaction set was distinct from that of the CHS3 network, indicating broad roles for Chs1p in buffering both Chs2p function and more global cell wall robustness. Conclusion Based on their interaction patterns and chitin levels we group interacting mutants into functional categories. Genes interacting with CHS3 are involved in the amelioration of cell wall defects and in septum or bud neck chitin synthesis, and we newly assign a number of genes to these functions. Our genetic analysis of genes not interacting with

Investigating chitin deacetylation and chitosan hydrolysis during vegetative growth in Magnaporthe oryzae.

PubMed

Geoghegan, Ivey A; Gurr, Sarah J

2017-09-01

Chitin deacetylation results in the formation of chitosan, a polymer of β1,4-linked glucosamine. Chitosan is known to have important functions in the cell walls of a number of fungal species, but its role during hyphal growth has not yet been investigated. In this study, we have characterized the role of chitin deacetylation during vegetative hyphal growth in the filamentous phytopathogen Magnaporthe oryzae. We found that chitosan localizes to the septa and lateral cell walls of vegetative hyphae and identified 2 chitin deacetylases expressed during vegetative growth-CDA1 and CDA4. Deletion strains and fluorescent protein fusions demonstrated that CDA1 is necessary for chitin deacetylation in the septa and lateral cell walls of mature hyphae in colony interiors, whereas CDA4 deacetylates chitin in the hyphae at colony margins. However, although the Δcda1 strain was more resistant to cell wall hydrolysis, growth and pathogenic development were otherwise unaffected in the deletion strains. The role of chitosan hydrolysis was also investigated. A single gene encoding a putative chitosanase (CSN) was discovered in M. oryzae and found to be expressed during vegetative growth. However, chitosan localization, vegetative growth, and pathogenic development were unaffected in a CSN deletion strain, rendering the role of this enzyme unclear. © 2017 The Authors Cellular Microbiology Published by John Wiley & Sons Ltd.

Implications of molecular diversity of chitin and its derivatives.

PubMed

Khan, Faez Iqbal; Rahman, Safikur; Queen, Aarfa; Ahamad, Shahzaib; Ali, Sher; Kim, Jihoe; Hassan, Md Imtaiyaz

2017-05-01

Chitin is a long unbranched polysaccharide, made up of β-1,4-linked N-acetylglucosamine which forms crystalline fiber-like structure. It is present in the fungal cell walls, insect and crustacean cuticles, nematode eggshells, and protozoa cyst. We provide a critical appraisal on the chemical modifications of chitin and its derivatives in the context of their improved efficacy in medical applications without any side effect. Recent advancement in nanobiotechnology has helped to synthesize several chitin derivatives having significant biological applications. Here, we discuss the molecular diversity of chitin and its applications in enzyme immobilization, wound healing, packaging material, controlled drug release, biomedical imaging, gene therapy, agriculture, biosensor, and cosmetics. Also, we highlighted chitin and its derivatives as an antioxidant, antimicrobial agent, anticoagulant material, food additive, and hypocholesterolemic agent. We envisage that chitin and chitosan-based nanomaterials with their potential applications would augment nanobiotechnology and biomedical industries.

Chitin based polyurethanes using hydroxyl terminated polybutadiene, part III: surface characteristics.

PubMed

Zia, Khalid Mahmood; Zuber, Mohammad; Saif, Muhammad Jawwad; Jawaid, Mohammad; Mahmood, Kashif; Shahid, Muhammad; Anjum, Muhammad Naveed; Ahmad, Mirza Nadeem

2013-11-01

Hydroxy terminated polybutadiene (HTPB)-chitin based polyurethanes (PUs) with controlled hydrophobicity were synthesized using HTPB and toluene diisocyanate (TDI). The prepolymer was extended with different mass ratios of chitin and 1,4-butane diol (BDO). The effect of chitin contents in chain extender (CE) proportions on surface properties was studied and investigated. Incorporation of chitin contents into the final PU showed decrease in contact angle value of water drop, water absorption (%) and swelling behavior. The antibacterial activity of the prepared samples was affected by varying the chitin contents in the chemical composition of the final PU. The results demonstrated that the use of prepared material can be suggested as non-absorbable suture. Copyright © 2013 Elsevier B.V. All rights reserved.

Salmonella biofilm formation on Aspergillus niger involves cellulose--chitin interactions.

PubMed

Brandl, Maria T; Carter, Michelle Q; Parker, Craig T; Chapman, Matthew R; Huynh, Steven; Zhou, Yaguang

2011-01-01

Salmonella cycles between host and nonhost environments, where it can become an active member of complex microbial communities. The role of fungi in the environmental adaptation of enteric pathogens remains relatively unexplored. We have discovered that S. enterica Typhimurium rapidly attaches to and forms biofilms on the hyphae of the common fungus, Aspergillus niger. Several Salmonella enterica serovars displayed a similar interaction, whereas other bacterial species were unable to bind to the fungus. Bacterial attachment to chitin, a major constituent of fungal cell walls, mirrored this specificity. Pre-incubation of S. Typhimurium with N-acetylglucosamine, the monomeric component of chitin, reduced binding to chitin beads by as much as 727-fold and inhibited attachment to A. niger hyphae considerably. A cellulose-deficient mutant of S. Typhimurium failed to attach to chitin beads and to the fungus. Complementation of this mutant with the cellulose operon restored binding to chitin beads to 79% of that of the parental strain and allowed for attachment and biofilm formation on A. niger, indicating that cellulose is involved in bacterial attachment to the fungus via the chitin component of its cell wall. In contrast to cellulose, S. Typhimurium curli fimbriae were not required for attachment and biofilm development on the hyphae but were critical for its stability. Our results suggest that cellulose-chitin interactions are required for the production of mixed Salmonella-A. niger biofilms, and support the hypothesis that encounters with chitinaceous alternate hosts may contribute to the ecological success of human pathogens.

Process for electrospinning chitin fibers from chitinous biomass solution

DOEpatents

Swatloski, Richard P.; Barber, Patrick S.; Opichka, Terrance; Bonner, Jonathan R.; Gurau, Gabriela; Griggs, Christopher Scott; Rogers, Robin D.

2017-06-20

Disclosed are methods for electrospinning chitinous biomass solution to form chitin fibers, using ionic liquids or other ion-containing liquids as solvent. Chitin fibers produced thereby and articles containing such chitin fibers are also disclosed. The chitin fiber thus obtained has very high surface area and improved strength over currently commercially available chitin materials.

High temperature induced disruption of the cell wall integrity and structure in Pleurotus ostreatus mycelia.

PubMed

Qiu, Zhiheng; Wu, Xiangli; Gao, Wei; Zhang, Jinxia; Huang, Chenyang

2018-05-30

Fungal cells are surrounded by a tight cell wall to protect them from harmful environmental conditions and to resist lysis. The synthesis and assembly determine the shape, structure, and integrity of the cell wall during the process of mycelial growth and development. High temperature is an important abiotic stress, which affects the synthesis and assembly of cell walls. In the present study, the chitin and β-1,3-glucan concentrations in the cell wall of Pleurotus ostreatus mycelia were changed after high-temperature treatment. Significantly higher chitin and β-1,3-glucan concentrations were detected at 36 °C than those incubated at 28 °C. With the increased temperature, many aberrant chitin deposition patches occurred, and the distribution of chitin in the cell wall was uneven. Moreover, high temperature disrupts the cell wall integrity, and P. ostreatus mycelia became hypersensitive to cell wall-perturbing agents at 36 °C. The cell wall structure tended to shrink or distorted after high temperature. The cell walls were observed to be thicker and looser by using transmission electron microscopy. High temperature can decrease the mannose content in the cell wall and increase the relative cell wall porosity. According to infrared absorption spectrum, high temperature broke or decreased the glycosidic linkages. Finally, P. ostreatus mycelial cell wall was easily degraded by lysing enzymes after high-temperature treatment. In other words, the cell wall destruction caused by high temperature may be a breakthrough for P. ostreatus to be easily infected by Trichoderma.

Salmonella Biofilm Formation on Aspergillus niger Involves Cellulose – Chitin Interactions

PubMed Central

Brandl, Maria T.; Carter, Michelle Q.; Parker, Craig T.; Chapman, Matthew R.; Huynh, Steven; Zhou, Yaguang

2011-01-01

Salmonella cycles between host and nonhost environments, where it can become an active member of complex microbial communities. The role of fungi in the environmental adaptation of enteric pathogens remains relatively unexplored. We have discovered that S. enterica Typhimurium rapidly attaches to and forms biofilms on the hyphae of the common fungus, Aspergillus niger. Several Salmonella enterica serovars displayed a similar interaction, whereas other bacterial species were unable to bind to the fungus. Bacterial attachment to chitin, a major constituent of fungal cell walls, mirrored this specificity. Pre-incubation of S. Typhimurium with N-acetylglucosamine, the monomeric component of chitin, reduced binding to chitin beads by as much as 727-fold and inhibited attachment to A. niger hyphae considerably. A cellulose-deficient mutant of S. Typhimurium failed to attach to chitin beads and to the fungus. Complementation of this mutant with the cellulose operon restored binding to chitin beads to 79% of that of the parental strain and allowed for attachment and biofilm formation on A. niger, indicating that cellulose is involved in bacterial attachment to the fungus via the chitin component of its cell wall. In contrast to cellulose, S. Typhimurium curli fimbriae were not required for attachment and biofilm development on the hyphae but were critical for its stability. Our results suggest that cellulose–chitin interactions are required for the production of mixed Salmonella-A. niger biofilms, and support the hypothesis that encounters with chitinaceous alternate hosts may contribute to the ecological success of human pathogens. PMID:22003399

A chitin deacetylase from the endophytic fungus Pestalotiopsis sp. efficiently inactivates the elicitor activity of chitin oligomers in rice cells.

PubMed

Cord-Landwehr, Stefan; Melcher, Rebecca L J; Kolkenbrock, Stephan; Moerschbacher, Bruno M

2016-11-30

To successfully survive in plants, endophytes need strategies to avoid being detected by the plant immune system, as the cell walls of endophytes contain easily detectible chitin. It is possible that endophytes "hide" this chitin from the plant immune system by modifying it, or oligomers derived from it, using chitin deacetylases (CDA). To explore this hypothesis, we identified and expressed a CDA from Pestalotiopsis sp. (PesCDA), an endophytic fungus, in E. coli and characterized this enzyme and its chitosan oligomer products. We found that when PesCDA modifies chitin oligomers, the products are partially deacetylated chitosan oligomers with a specific acetylation pattern: GlcNAc-GlcNAc-(GlcN) n -GlcNAc (n ≥ 1). Then, in a bioactivity assay where suspension-cultured rice cells were incubated with the PesCDA products (processed chitin hexamers), we found that, unlike the substrate hexamers, chitosan oligomer products no longer elicited the plant immune system. Thus, this endophytic enzyme can prevent the endophyte from being recognized by the plant immune system; this might represent a more general hypothesis for how certain fungi are able to live in or on their hosts.

A chitin deacetylase from the endophytic fungus Pestalotiopsis sp. efficiently inactivates the elicitor activity of chitin oligomers in rice cells

PubMed Central

Cord-Landwehr, Stefan; Melcher, Rebecca L. J.; Kolkenbrock, Stephan; Moerschbacher, Bruno M.

2016-01-01

To successfully survive in plants, endophytes need strategies to avoid being detected by the plant immune system, as the cell walls of endophytes contain easily detectible chitin. It is possible that endophytes “hide” this chitin from the plant immune system by modifying it, or oligomers derived from it, using chitin deacetylases (CDA). To explore this hypothesis, we identified and expressed a CDA from Pestalotiopsis sp. (PesCDA), an endophytic fungus, in E. coli and characterized this enzyme and its chitosan oligomer products. We found that when PesCDA modifies chitin oligomers, the products are partially deacetylated chitosan oligomers with a specific acetylation pattern: GlcNAc-GlcNAc-(GlcN)n-GlcNAc (n ≥ 1). Then, in a bioactivity assay where suspension-cultured rice cells were incubated with the PesCDA products (processed chitin hexamers), we found that, unlike the substrate hexamers, chitosan oligomer products no longer elicited the plant immune system. Thus, this endophytic enzyme can prevent the endophyte from being recognized by the plant immune system; this might represent a more general hypothesis for how certain fungi are able to live in or on their hosts. PMID:27901067

Chitin synthase III: synthetic lethal mutants and "stress related" chitin synthesis that bypasses the CSD3/CHS6 localization pathway.

PubMed

Osmond, B C; Specht, C A; Robbins, P W

1999-09-28

We screened Saccharomyces strains for mutants that are synthetically lethal with deletion of the major chitin synthase gene CHS3. In addition to finding, not surprisingly, that mutations in major cell wall-related genes such as FKS1 (glucan synthase) and mutations in any of the Golgi glycosylation complex genes (MNN9 family) are lethal in combination with chs3Delta, we found that a mutation in Srv2p, a bifunctional regulatory gene, is notably lethal in the chs3 deletion. In extending studies of fks1-chitin synthase 3 interactions, we made the surprising discovery that deletion of CSD3/CHS6, a gene normally required for Chs3p delivery and activity in vivo, was not lethal with fks1 and, in fact, that lack of Csd3p/Chs6p did not decrease the high level of stress-related chitin made in the fks1 mutant. This finding suggests that "stress response" chitin synthesis proceeds through an alternate Chs3p targeting pathway.

Substantial decrease in cell wall α-1,3-glucan caused by disruption of the kexB gene encoding a subtilisin-like processing protease in Aspergillus oryzae.

PubMed

Mizutani, Osamu; Shiina, Matsuko; Yoshimi, Akira; Sano, Motoaki; Watanabe, Takeshi; Yamagata, Youhei; Nakajima, Tasuku; Gomi, Katsuya; Abe, Keietsu

2016-09-01

Disruption of the kexB encoding a subtilisin-like processing protease in Aspergillus oryzae (ΔkexB) leads to substantial morphological defects when the cells are grown on Czapek-Dox agar plates. We previously found that the disruption of kexB causes a constitutive activation of the cell wall integrity pathway. To understand how the disruption of the kexB affects cell wall organization and components, we analyzed the cell wall of ΔkexB grown on the plates. The results revealed that both total N-acetylglucosamine content, which constitutes chitin, and chitin synthase activities were increased. Whereas total glucose content, which constitutes β-1,3-glucan and α-1,3-glucan, was decreased; this decrease was attributed to a remarkable decrease in α-1,3-glucan. Additionally, the β-1,3-glucan in the alkali-insoluble fraction of the ΔkexB showed a high degree of polymerization. These results suggested that the loss of α-1,3-glucan in the ΔkexB was compensated by increases in the chitin content and the average degree of β-1,3-glucan polymerization.

Chitin Research Revisited

PubMed Central

Khoushab, Feisal; Yamabhai, Montarop

2010-01-01

Two centuries after the discovery of chitin, it is widely accepted that this biopolymer is an important biomaterial in many aspects. Numerous studies on chitin have focused on its biomedical applications. In this review, various aspects of chitin research including sources, structure, biosynthesis, chitinolytic enzyme, chitin binding protein, genetic engineering approach to produce chitin, chitin and evolution, and a wide range of applications in bio- and nanotechnology will be dealt with. PMID:20714419

Chitin in the Silk Gland Ducts of the Spider Nephila edulis and the Silkworm Bombyx mori

PubMed Central

Davies, Gwilym J. G.; Knight, David P.; Vollrath, Fritz

2013-01-01

Here we report the detection and localisation of chitin in the cuticle of the spinning ducts of both the spider Nephila edulis and the silkworm Bombyx mori. Our observations demonstrate that the duct walls of both animals contain chitin notwithstanding totally independent evolutionary pathways of the systems. We conclude that chitin may well be an essential component for the construction of spinning ducts; we further conclude that in both species chitin may indicate the evolutionary origin of the spinning ducts. PMID:24015298

Chitin and Chitosan: Production and Application of Versatile Biomedical Nanomaterials

PubMed Central

Elieh-Ali-Komi, Daniel; Hamblin, Michael R

2016-01-01

Chitin is the most abundant aminopolysaccharide polymer occurring in nature, and is the building material that gives strength to the exoskeletons of crustaceans, insects, and the cell walls of fungi. Through enzymatic or chemical deacetylation, chitin can be converted to its most well-known derivative, chitosan. The main natural sources of chitin are shrimp and crab shells, which are an abundant byproduct of the food-processing industry, that provides large quantities of this biopolymer to be used in biomedical applications. In living chitin-synthesizing organisms, the synthesis and degradation of chitin require strict enzymatic control to maintain homeostasis. Chitin synthase, the pivotal enzyme in the chitin synthesis pathway, uses UDP-N-acetylglucosamine (UDPGlcNAc), produce the chitin polymer, whereas, chitinase enzymes degrade chitin. Bacteria are considered as the major mediators of chitin degradation in nature. Chitin and chitosan, owing to their unique biochemical properties such as biocompatibility, biodegradability, non-toxicity, ability to form films, etc, have found many promising biomedical applications. Nanotechnology has also increasingly applied chitin and chitosan-based materials in its most recent achievements. Chitin and chitosan have been widely employed to fabricate polymer scaffolds. Moreover, the use of chitosan to produce designed-nanocarriers and to enable microencapsulation techniques is under increasing investigation for the delivery of drugs, biologics and vaccines. Each application is likely to require uniquely designed chitosan-based nano/micro-particles with specific dimensions and cargo-release characteristics. The ability to reproducibly manufacture chitosan nano/microparticles that can encapsulate protein cargos with high loading efficiencies remains a challenge. Chitosan can be successfully used in solution, as hydrogels and/or nano/microparticles, and (with different degrees of deacetylation) an endless array of derivatives with

Chitin synthase III: Synthetic lethal mutants and “stress related” chitin synthesis that bypasses the CSD3/CHS6 localization pathway

PubMed Central

Osmond, Barbara C.; Specht, Charles A.; Robbins, Phillips W.

1999-01-01

We screened Saccharomyces strains for mutants that are synthetically lethal with deletion of the major chitin synthase gene CHS3. In addition to finding, not surprisingly, that mutations in major cell wall-related genes such as FKS1 (glucan synthase) and mutations in any of the Golgi glycosylation complex genes (MNN9 family) are lethal in combination with chs3Δ, we found that a mutation in Srv2p, a bifunctional regulatory gene, is notably lethal in the chs3 deletion. In extending studies of fks1-chitin synthase 3 interactions, we made the surprising discovery that deletion of CSD3/CHS6, a gene normally required for Chs3p delivery and activity in vivo, was not lethal with fks1 and, in fact, that lack of Csd3p/Chs6p did not decrease the high level of stress-related chitin made in the fks1 mutant. This finding suggests that “stress response” chitin synthesis proceeds through an alternate Chs3p targeting pathway. PMID:10500155

N-acetylglucosamine affects Cryptococcus neoformans cell-wall composition and melanin architecture.

PubMed

Camacho, Emma; Chrissian, Christine; Cordero, Radames J B; Liporagi-Lopes, Livia; Stark, Ruth E; Casadevall, Arturo

2017-11-01

Cryptococcus neoformans is an environmental fungus that belongs to the phylum Basidiomycetes and is a major pathogen in immunocompromised patients. The ability of C. neoformans to produce melanin pigments represents its second most important virulence factor, after the presence of a polysaccharide capsule. Both the capsule and melanin are closely associated with the fungal cell wall, a complex structure that is essential for maintaining cell morphology and viability under conditions of stress. The amino sugar N-acetylglucosamine (GlcNAc) is a key constituent of the cell-wall chitin and is used for both N-linked glycosylation and GPI anchor synthesis. Recent studies have suggested additional roles for GlcNAc as an activator and mediator of cellular signalling in fungal and plant cells. Furthermore, chitin and chitosan polysaccharides interact with melanin pigments in the cell wall and have been found to be essential for melanization. Despite the importance of melanin, its molecular structure remains unresolved; however, we previously obtained critical insights using advanced nuclear magnetic resonance (NMR) and imaging techniques. In this study, we investigated the effect of GlcNAc supplementation on cryptococcal cell-wall composition and melanization. C. neoformans was able to metabolize GlcNAc as a sole source of carbon and nitrogen, indicating a capacity to use a component of a highly abundant polymer in the biospherenutritionally. C. neoformans cells grown with GlcNAc manifested changes in the chitosan cell-wall content, cell-wall thickness and capsule size. Supplementing cultures with isotopically 15 N-labelled GlcNAc demonstrated that the exogenous monomer serves as a building block for chitin/chitosan and is incorporated into the cell wall. The altered chitin-to-chitosan ratio had no negative effects on the mother-daughter cell separation; growth with GlcNAc affected the fungal cell-wall scaffold, resulting in increased melanin deposition and assembly. In

N-acetylglucosamine affects Cryptococcus neoformans cell-wall composition and melanin architecture

PubMed Central

Camacho, Emma; Chrissian, Christine; Cordero, Radames J. B.; Liporagi-Lopes, Livia; Stark, Ruth E.; Casadevall, Arturo

2017-01-01

Cryptococcus neoformans is an environmental fungus that belongs to the phylum Basidiomycetes and is a major pathogen in immunocompromised patients. The ability of C. neoformans to produce melanin pigments represents its second most important virulence factor, after the presence of a polysaccharide capsule. Both the capsule and melanin are closely associated with the fungal cell wall, a complex structure that is essential for maintaining cell morphology and viability under conditions of stress. The amino sugar N-acetylglucosamine (GlcNAc) is a key constituent of the cell-wall chitin and is used for both N-linked glycosylation and GPI anchor synthesis. Recent studies have suggested additional roles for GlcNAc as an activator and mediator of cellular signalling in fungal and plant cells. Furthermore, chitin and chitosan polysaccharides interact with melanin pigments in the cell wall and have been found to be essential for melanization. Despite the importance of melanin, its molecular structure remains unresolved; however, we previously obtained critical insights using advanced nuclear magnetic resonance (NMR) and imaging techniques. In this study, we investigated the effect of GlcNAc supplementation on cryptococcal cell-wall composition and melanization. C. neoformans was able to metabolize GlcNAc as a sole source of carbon and nitrogen, indicating a capacity to use a component of a highly abundant polymer in the biospherenutritionally. C. neoformans cells grown with GlcNAc manifested changes in the chitosan cell-wall content, cell-wall thickness and capsule size. Supplementing cultures with isotopically 15N-labelled GlcNAc demonstrated that the exogenous monomer serves as a building block for chitin/chitosan and is incorporated into the cell wall. The altered chitin-to-chitosan ratio had no negative effects on the mother–daughter cell separation; growth with GlcNAc affected the fungal cell-wall scaffold, resulting in increased melanin deposition and assembly. In

Drosophila Chitinase 2 is expressed in chitin producing organs for cuticle formation.

PubMed

Pesch, Yanina-Yasmin; Riedel, Dietmar; Behr, Matthias

2017-01-01

The architecture of the outer body wall cuticle is fundamental to protect arthropods against invading pathogens and numerous other harmful stresses. Such robust cuticles are formed by parallel running chitin microfibrils. Molting and also local wounding leads to dynamic assembly and disassembly of the chitin-matrix throughout development. However, the underlying molecular mechanisms that organize proper chitin-matrix formation are poorly known. Recently we identified a key region for cuticle thickening at the apical cell surface, the cuticle assembly zone, where Obstructor-A (Obst-A) coordinates the formation of the chitin-matrix. Obst-A binds chitin and the deacetylase Serpentine (Serp) in a core complex, which is required for chitin-matrix maturation and preservation. Here we present evidence that Chitinase 2 (Cht2) could be essential for this molecular machinery. We show that Cht2 is expressed in the chitin-matrix of epidermis, trachea, and the digestive system. There, Cht2 is enriched at the apical cell surface and the dense chitin-matrix. We further show that in Cht2 knockdown larvae the assembly zone is rudimentary, preventing normal cuticle formation and pore canal organization. As sequence similarities of Cht2 and the core complex proteins indicate evolutionarily conserved molecular mechanisms, our findings suggest that Cht2 is involved in chitin formation also in other insects. Copyright © 2016 Elsevier Ltd. All rights reserved.

A chitin synthase and its regulator protein are critical for chitosan production and growth of the fungal pathogen Cryptococcus neoformans.

PubMed

Banks, Isaac R; Specht, Charles A; Donlin, Maureen J; Gerik, Kimberly J; Levitz, Stuart M; Lodge, Jennifer K

2005-11-01

Chitin is an essential component of the cell wall of many fungi. Chitin also can be enzymatically deacetylated to chitosan, a more flexible and soluble polymer. Cryptococcus neoformans is a fungal pathogen that causes cryptococcal meningoencephalitis, particularly in immunocompromised patients. In this work, we show that both chitin and chitosan are present in the cell wall of vegetatively growing C. neoformans yeast cells and that the levels of both rise dramatically as cells grow to higher density in liquid culture. C. neoformans has eight putative chitin synthases, and strains with any one chitin synthase deleted are viable at 30 degrees C. In addition, C. neoformans genes encode three putative regulator proteins, which are homologs of Saccharomyces cerevisiae Skt5p. None of these three is essential for viability. However, one of the chitin synthases (Chs3) and one of the regulators (Csr2) are important for growth. Cells with deletions in either CHS3 or CSR2 have several shared phenotypes, including sensitivity to growth at 37 degrees C. The similarity of their phenotypes also suggests that Csr2 specifically regulates chitin synthesis by Chs3. Lastly, both chs3Delta and the csr2Delta mutants are defective in chitosan production, predicting that Chs3-Csr2 complex with chitin deacetylases for conversion of chitin to chitosan. These data suggest that chitin synthesis could be an excellent antifungal target.

Identification of potential cell wall component that allows Taka-amylase A adsorption in submerged cultures of Aspergillus oryzae.

PubMed

Sato, Hiroki; Toyoshima, Yoshiyuki; Shintani, Takahiro; Gomi, Katsuya

2011-12-01

We observed that α-amylase (Taka-amylase A; TAA) activity in the culture broth disappeared in the later stage of submerged cultivation of Aspergillus oryzae. This disappearance was caused by adsorption of TAA onto the cell wall of A. oryzae and not due to protein degradation by extracellular proteolytic enzymes. To determine the cell wall component(s) that allows TAA adsorption efficiently, the cell wall was fractionated by stepwise alkali treatment and enzymatic digestion. Consequently, alkali-insoluble cell wall fractions exhibited high levels of TAA adsorption. In addition, this adsorption capacity was significantly enhanced by treatment of the alkali-insoluble fraction with β-glucanase, which resulted in the concomitant increase in the amount of chitin in the resulting fraction. In contrast, the adsorption capacity was diminished by treating the cell wall fraction with chitinase. These results suggest that the major component that allows TAA adsorption is chitin. However, both the mycelium and the cell wall demonstrated the inability to allow TAA adsorption in the early stage of cultivation, despite chitin content in the cell wall being identical in both early and late stages of cultivation. These results suggest the existence of unidentified factor(s) that could prevent the adsorption of TAA onto the cell wall. Such factor(s) is most likely removed or diminished from the cell wall following longer cultivation periods.

[In Vivo Study of Chitin in Fungal Hyphae Based on Confocal Raman Microscopy].

PubMed

Li, Xiao-li; Luo, Liu-bin; Zhou, Bin-xiong; Hu, Xiao-qian; Sun, Chan-jun; He, Yong

2016-01-01

Chitin is an important structural polysaccharide of fungal cell wall. In this paper, aerial hyphae of Colletotrichum camelliae Massee was first studied by confocal Raman microscopy in vivo. Firstly, the optimal experimental parameters of hyphae for collecting the Raman spectra were determined, and the typical Raman spectra of hyphae, chitin standard and background were acquired. By comparing analysis, characteristic peaks of chitin were found in hyphae. Then, a region of interesting on hyphae was selected for Raman scanning. Through principal component analysis, the Raman signal of hyphae and background in the scanning area can be separated clearly. Combined with loading weight plot, two main characteristic peaks of hyphae were obtained, 1 622 cm(-1) was belong to chitin and 1 368 cm(-1) was assigned to pectic polysaccharide. Finally, two and three dimension chemical images of fungal hyphae were realized based on Raman fingerprint spectra of chitin in a nondestructive way.

A Chitin Synthase and Its Regulator Protein Are Critical for Chitosan Production and Growth of the Fungal Pathogen Cryptococcus neoformans†

PubMed Central

Banks, Isaac R.; Specht, Charles A.; Donlin, Maureen J.; Gerik, Kimberly J.; Levitz, Stuart M.; Lodge, Jennifer K.

2005-01-01

Chitin is an essential component of the cell wall of many fungi. Chitin also can be enzymatically deacetylated to chitosan, a more flexible and soluble polymer. Cryptococcus neoformans is a fungal pathogen that causes cryptococcal meningoencephalitis, particularly in immunocompromised patients. In this work, we show that both chitin and chitosan are present in the cell wall of vegetatively growing C. neoformans yeast cells and that the levels of both rise dramatically as cells grow to higher density in liquid culture. C. neoformans has eight putative chitin synthases, and strains with any one chitin synthase deleted are viable at 30°C. In addition, C. neoformans genes encode three putative regulator proteins, which are homologs of Saccharomyces cerevisiae Skt5p. None of these three is essential for viability. However, one of the chitin synthases (Chs3) and one of the regulators (Csr2) are important for growth. Cells with deletions in either CHS3 or CSR2 have several shared phenotypes, including sensitivity to growth at 37°C. The similarity of their phenotypes also suggests that Csr2 specifically regulates chitin synthesis by Chs3. Lastly, both chs3Δ and the csr2Δ mutants are defective in chitosan production, predicting that Chs3-Csr2 complex with chitin deacetylases for conversion of chitin to chitosan. These data suggest that chitin synthesis could be an excellent antifungal target. PMID:16278457

Identification and characterization of a class III chitin synthase gene of Moniliophthora perniciosa, the fungus that causes witches' broom disease of cacao.

PubMed

Souza, Catiane S; Oliveira, Bruno M; Costa, Gustavo G L; Schriefer, Albert; Selbach-Schnadelbach, Alessandra; Uetanabaro, Ana Paula T; Pirovani, Carlos P; Pereira, Gonçalo A G; Taranto, Alex G; Cascardo, Júlio Cézar de M; Góes-Neto, Aristóteles

2009-08-01

Chitin synthase (CHS) is a glucosyltransferase that converts UDP-N-acetylglucosamine into chitin, one of the main components of fungal cell wall. Class III chitin synthases act directly in the formation of the cell wall. They catalyze the conversion of the immediate precursor of chitin and are responsible for the majority of chitin synthesis in fungi. As such, they are highly specific molecular targets for drugs that can inhibit the growth and development of fungal pathogens. In this work, we have identified and characterized a chitin synthase gene of Moniliophthora perniciosa (Mopchs) by primer walking. The complete gene sequence is 3,443 bp, interrupted by 13 small introns, and comprises a cDNA with an ORF with 2,739 bp, whose terminal region was experimentally determined, encoding a protein with 913 aa that harbors all the motifs and domains typically found in class III chitin synthases. This is the first report on the characterization of a chitin synthase gene, its mature transcription product, and its putative protein in basidioma and secondary mycelium stages of M. perniciosa, a basidiomycotan fungus that causes witches' broom disease of cacao.

Complement Component 3C3 and C3a Receptor Are Required in Chitin-Dependent Allergic Sensitization to Aspergillus fumigatus but Dispensable in Chitin-Induced Innate Allergic Inflammation

PubMed Central

Roy, René M.; Paes, Hugo C.; Nanjappa, Som G.; Sorkness, Ron; Gasper, David; Sterkel, Alana; Wüthrich, Marcel; Klein, Bruce S.

2013-01-01

ABSTRACT Levels of the anaphylatoxin C3a are increased in patients with asthma compared with those in nonasthmatics and increase further still during asthma exacerbations. However, the role of C3a during sensitization to allergen is poorly understood. Sensitization to fungal allergens, such as Aspergillus fumigatus, is a strong risk factor for the development of asthma. Exposure to chitin, a structural polysaccharide of the fungal cell wall, induces innate allergic inflammation and may promote sensitization to fungal allergens. Here, we found that coincubation of chitin with serum or intratracheal administration of chitin in mice resulted in the generation of C3a. We established a model of chitin-dependent sensitization to soluble Aspergillus antigens to test the contribution of complement to these events. C3−/− and C3aR−/− mice were protected from chitin-dependent sensitization to Aspergillus and had reduced lung eosinophilia and type 2 cytokines and serum IgE. In contrast, complement-deficient mice were not protected against chitin-induced innate allergic inflammation. In sensitized mice, plasmacytoid dendritic cells from complement-deficient animals acquired a tolerogenic profile associated with enhanced regulatory T cell responses and suppressed Th2 and Th17 responses specific for Aspergillus. Thus, chitin induces the generation of C3a in the lung, and chitin-dependent allergic sensitization to Aspergillus requires C3aR signaling, which suppresses regulatory dendritic cells and T cells and induces allergy-promoting T cells. PMID:23549917

Fungal effector Ecp6 outcompetes host immune receptor for chitin binding through intrachain LysM dimerization

PubMed Central

Kombrink, Anja; Hansen, Guido; Valkenburg, Dirk-Jan

2013-01-01

While host immune receptors detect pathogen-associated molecular patterns to activate immunity, pathogens attempt to deregulate host immunity through secreted effectors. Fungi employ LysM effectors to prevent recognition of cell wall-derived chitin by host immune receptors, although the mechanism to compete for chitin binding remained unclear. Structural analysis of the LysM effector Ecp6 of the fungal tomato pathogen Cladosporium fulvum reveals a novel mechanism for chitin binding, mediated by intrachain LysM dimerization, leading to a chitin-binding groove that is deeply buried in the effector protein. This composite binding site involves two of the three LysMs of Ecp6 and mediates chitin binding with ultra-high (pM) affinity. Intriguingly, the remaining singular LysM domain of Ecp6 binds chitin with low micromolar affinity but can nevertheless still perturb chitin-triggered immunity. Conceivably, the perturbation by this LysM domain is not established through chitin sequestration but possibly through interference with the host immune receptor complex. DOI: http://dx.doi.org/10.7554/eLife.00790.001 PMID:23840930

Characterization of a Novel, Antifungal, Chitin-Binding Protein from Streptomyces tendae Tü901 That Interferes with Growth Polarity

PubMed Central

Bormann, Christiane; Baier, Daniel; Hörr, Ingmar; Raps, Claudia; Berger, Jürgen; Jung, Günther; Schwarz, Heinz

1999-01-01

The afp1 gene, which encodes the antifungal protein AFP1, was cloned from nikkomycin-producing Streptomyces tendae Tü901, using a nikkomycin-negative mutant as a host and screening transformants for antifungal activity against Paecilomyces variotii in agar diffusion assays. The 384-bp afp1 gene has a low G+C content (63%) and a transcription termination structure with a poly(T) region, unusual attributes for Streptomyces genes. AFP1 was purified from culture filtrate of S. tendae carrying the afp1 gene on the multicopy plasmid pIJ699. The purified protein had a molecular mass of 9,862 Da and lacked a 42-residue N-terminal peptide deduced from the nucleotide sequence. AFP1 was stable at extreme pH values and high temperatures and toward commercial proteinases. AFP1 had limited similarity to cellulose-binding domains of microbial plant cell wall hydrolases and bound to crab shell chitin, chitosan, and cell walls of P. variotii but showed no enzyme activity. The biological activity of AFP1, which represents the first chitin-binding protein from bacteria exhibiting antifungal activity, was directed against specific ascomycetes, and synergistic interaction with the chitin synthetase inhibitor nikkomycin inhibited growth of Aspergillus species. Microscopy studies revealed that fluorescein-labeled AFP1 strongly bound to the surface of germinated conidia and to tips of growing hyphae, causing severe alterations in cell morphogenesis that gave rise to large spherical conidia and/or swollen hyphae and to atypical branching. PMID:10601197

Comparison of Extraction Methods of Chitin from Ganoderma lucidum Mushroom Obtained in Submerged Culture

PubMed Central

Ospina Álvarez, Sandra Patricia; Ramírez Cadavid, David Alexander; Ossa Orozco, Claudia Patricia; Zapata Ocampo, Paola; Atehortúa, Lucía

2014-01-01

The chitin was isolated from the Ganoderma lucidum submerged cultures mycelium as potential source of chitin under biotechnological processes. The extraction of chitin was carried out through 5 different assays which involved mainly three phases: pulverization of the mushroom, deproteinization of the mycelia with NaOH solution, and a process of decolorization with potassium permanganate and oxalic acid. The chitin contents extracted from 9-day mycelia were 413, 339, 87, 78, and 144 mg/g−1 (milligrams of chitin/grams of dry biomass) for A1, A2, A3, A4, and A5, respectively. Obtained chitin was characterized by X-Ray Diffraction (XRD), by Fourier transform infrared spectroscopy (FTIR), and by thermal analysis (TGA). The results showed that Ganoderma lucidum chitin has similar characteristic of chitin from different fonts. The advantage of the biotechnological processes and the fact that Ganoderma lucidum fungus may be used as a potential raw material for chitin production were demonstrated. PMID:24551839

Go Fly a Chitin: The Mystery of Chitin and Chitinases in Vertebrate Tissues.

PubMed

Stern, Robert

2017-01-01

A controversy arose decades ago whether the DG42 gene product expressed during frog embryogenesis synthesized hyaluronan or chitin. Both sets of investigators were correct. It is now possible to understand how prescient those findings were. Synthesis of a seven to nine chitin sugar chain fragment is required before hyaluronan synthesis begins. Thus, DG42 indeed synthesizes both hyaluronan and chitin. Hyaluronan turns over rapidly in vertebrate tissues, but chitin oligomers are difficult to degrade. They accumulate and can cause pathology. Chitin is a simple beta-linked repeating sugar homopolymer found prominently in the building block structures of fungi, molluscs, arthropods, and other forms of invertebrate life. It is a highly resistant insoluble material requiring chitin synthases for production and chitinases for degradation. Mysteriously, chitins and chitinases also occur in vertebrate tissues, while it had previously been assumed that no chitins were contained therein. That assumption is now challenged based on recent biochemical evidence. Chitin does accumulate in many tissues, but may be particularly toxic to neurons. Its accumulation in the brain may account for the cognitive decline found in patients with Alzheimer's disease. The DG42 observations together with the participation of chitins and chitinases in several human diseases, among which in addition to Alzheimer's disease include Gaucher's disease, asthma, and aspects of abnormal immune recognition justify a reexamination of these topics. The purpose of this review is to summarize data in order to place chitins and their attendant enzymes in a rational framework in an attempt to create a cohesive story.

Preparation of Chitin-PLA laminated composite for implantable application.

PubMed

Nasrin, Romana; Biswas, Shanta; Rashid, Taslim Ur; Afrin, Sanjida; Jahan, Rumana Akhter; Haque, Papia; Rahman, Mohammed Mizanur

2017-12-01

The present study explores the possibilities of using locally available inexpensive waste prawn shell derived chitin reinforced and bioabsorbable polylactic acid (PLA) laminated composites to develop new materials with excellent mechanical and thermal properties for implantable application such as in bone or dental implant. Chitin at different concentration (1-20% of PLA) reinforced PLA films (CTP) were fabricated by solvent casting process and laminated chitin-PLA composites (LCTP) were prepared by laminating PLA film (obtained by hot press method) with CTP also by hot press method at 160 °C. The effect of variation of chitin concentration on the resulting laminated composite's behavior was investigated. The detailed physico-mechanical, surface morphology and thermal were assessed with different characterization technique such as FT-IR, XRD, SEM and TGA. The FTIR spectra showed the characteristic peaks for chitin and PLA in the composites. SEM images showed an excellent dispersion of chitin in the films and composites. Thermogravimetric analysis (TGA) showed that the complete degradation of chitin, PLA film, 5% chitin reinforced PLA film (CTP2) and LCTP are 98%, 95%, 87% and 98% respectively at temperature of 500 °C. The tensile strength of the LCTP was found 25.09 MPa which is significantly higher than pure PLA film (18.55 MPa) and CTP2 film (8.83 MPa). After lamination of pure PLA and CTP2 film, the composite (LCTP) yielded 0.265-1.061% water absorption from 30 min to 24 h immerse in water that is much lower than PLA and CTP. The increased mechanical properties of the laminated films with the increase of chitin content indicated good dispersion of chitin into PLA and strong interfacial actions between the polymer and chitin. The improvement of mechanical properties and the results of antimicrobial and cytotoxicity of the composites also evaluated and revealed the composite would be a suitable candidate for implant application in biomedical sector.

Gut immunity in a protochordate involves a secreted immunoglobulin-type mediator binding host chitin and bacteria.

PubMed

Dishaw, Larry J; Leigh, Brittany; Cannon, John P; Liberti, Assunta; Mueller, M Gail; Skapura, Diana P; Karrer, Charlotte R; Pinto, Maria R; De Santis, Rosaria; Litman, Gary W

2016-02-15

Protochordate variable region-containing chitin-binding proteins (VCBPs) consist of immunoglobulin-type V domains and a chitin-binding domain (CBD). VCBP V domains facilitate phagocytosis of bacteria by granulocytic amoebocytes; the function of the CBD is not understood. Here we show that the gut mucosa of Ciona intestinalis contains an extensive matrix of chitin fibrils to which VCBPs bind early in gut development, before feeding. Later in development, VCBPs and bacteria colocalize to chitin-rich mucus along the intestinal wall. VCBP-C influences biofilm formation in vitro and, collectively, the findings of this study suggest that VCBP-C may influence the overall settlement and colonization of bacteria in the Ciona gut. Basic relationships between soluble immunoglobulin-type molecules, endogenous chitin and bacteria arose early in chordate evolution and are integral to the overall function of the gut barrier.

Pharyngeal Polysaccharide Deacetylases Affect Development in the Nematode C. elegans and Deacetylate Chitin In Vitro

PubMed Central

Heustis, Ronald J.; Ng, Hong K.; Brand, Kenneth J.; Rogers, Meredith C.; Le, Linda T.; Specht, Charles A.; Fuhrman, Juliet A.

2012-01-01

Chitin (β-1,4-linked-N-acetylglucosamine) provides structural integrity to the nematode eggshell and pharyngeal lining. Chitin is synthesized in nematodes, but not in plants and vertebrates, which are often hosts to parasitic roundworms; hence, the chitin metabolism pathway is considered a potential target for selective interventions. Polysaccharide deacetylases (PDAs), including those that convert chitin to chitosan, have been previously demonstrated in protists, fungi and insects. We show that genes encoding PDAs are distributed throughout the phylum Nematoda, with the two paralogs F48E3.8 and C54G7.3 found in C. elegans. We confirm that the genes are somatically expressed and show that RNAi knockdown of these genes retards C. elegans development. Additionally, we show that proteins from the nematode deacetylate chitin in vitro, we quantify the substrate available in vivo as targets of these enzymes, and we show that Eosin Y (which specifically stains chitosan in fungal cells walls) stains the C. elegans pharynx. Our results suggest that one function of PDAs in nematodes may be deacetylation of the chitinous pharyngeal lining. PMID:22808160

Pharyngeal polysaccharide deacetylases affect development in the nematode C. elegans and deacetylate chitin in vitro.

PubMed

Heustis, Ronald J; Ng, Hong K; Brand, Kenneth J; Rogers, Meredith C; Le, Linda T; Specht, Charles A; Fuhrman, Juliet A

2012-01-01

Chitin (β-1,4-linked-N-acetylglucosamine) provides structural integrity to the nematode eggshell and pharyngeal lining. Chitin is synthesized in nematodes, but not in plants and vertebrates, which are often hosts to parasitic roundworms; hence, the chitin metabolism pathway is considered a potential target for selective interventions. Polysaccharide deacetylases (PDAs), including those that convert chitin to chitosan, have been previously demonstrated in protists, fungi and insects. We show that genes encoding PDAs are distributed throughout the phylum Nematoda, with the two paralogs F48E3.8 and C54G7.3 found in C. elegans. We confirm that the genes are somatically expressed and show that RNAi knockdown of these genes retards C. elegans development. Additionally, we show that proteins from the nematode deacetylate chitin in vitro, we quantify the substrate available in vivo as targets of these enzymes, and we show that Eosin Y (which specifically stains chitosan in fungal cells walls) stains the C. elegans pharynx. Our results suggest that one function of PDAs in nematodes may be deacetylation of the chitinous pharyngeal lining.

Expression of a chitin deacetylase gene, up-regulated in Cryptococcus laurentii strain RY1, under nitrogen limitation.

PubMed

Chakraborty, Writachit; Sarkar, Soumyadev; Chakravorty, Somnath; Bhattacharya, Semantee; Bhattacharya, Debanjana; Gachhui, Ratan

2016-05-01

This study reports the identification of a chitin deacetylase gene in Cryptococcus laurentii strain RY1 over-expressing under nitrogen limitation by differential display. The up-regulation took place in robustly growing cells rather than in starving quiescent autophagic cells. Quantitative Real Time-PCR, enzyme activity in cell lysate and cell wall analysis corroborated the up-regulation of chitin deacetylase under nitrogen limitation. These results suggest chitin deacetylase might play a significant role in nitrogen limiting growth of Cryptococcus laurentii strain RY1. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Graft polymerization of acrylic acid onto chitin nanofiber to improve dispersibility in basic water.

PubMed

Ifuku, Shinsuke; Iwasaki, Masayoshi; Morimoto, Minoru; Saimoto, Hiroyuki

2012-09-01

Graft copolymerization of acrylic acid (AA) on chitin nanofibers was carried out with potassium persulfate as a free radical initiator in an aqueous medium. The molar ratio of grafted AA increased with the AA concentration. The grafted chitin nanofibers were characterized by FT-IR, FE-SEM, UV-vis, XRD, and TGA. After polymerization, the characteristic morphology of chitin nanofibers was maintained. Chitin nanofibers grafted with AA were efficiently dissociated and dispersed homogeneously in basic water because of the electrostatic repulsion effect between nanofibers. AA was grafted on the surface and amorphous part of chitin nanofibers, and the original crystalline structure of α-chitin was maintained. At 330 °C, the weight residue of the graft copolymer increased with the grafted AA content. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of purification method of β-chitin from squid pen on the properties of β-chitin nanofibers.

PubMed

Suenaga, Shin; Nikaido, Nozomi; Totani, Kazuhide; Kawasaki, Kazunori; Ito, Yoshihito; Yamashita, Kazuhiko; Osada, Mitsumasa

2016-10-01

The relationship between purification methods of β-chitin from squid pen and the physicochemical properties of β-chitin nanofibers (NFs) were investigated. Two types of β-chitin were prepared, with β-chitin (a→b) subjected to acid treatment for decalcification and then base treatment for deproteinization, while β-chitin (b→a) was treated in the opposite order. These β-chitins were disintegrated into NFs using wet pulverization. The β-chitin (b→a) NF dispersion has higher transmittance and viscosity than the β-chitin (a→b) NF dispersion. For the first time, we succeeded in obtaining 3D images of the β-chitin NF dispersion in water by using quick-freeze deep-etch replication with high-angle annular dark field scanning transmission electron microscopy. The β-chitin (b→a) NF dispersion has a denser and more uniform 3D network structure than the β-chitin (a→b) NF dispersion. Widths of the β-chitin (a→b) and (b→a) NFs were approximately 8-25 and 3-10nm, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

"Chitin-specific" peroxidases in plants.

PubMed

Maksimov, I V; Cherepanova, E A; Khairullin, R M

2003-01-01

The activity of various plant peroxidases and the ability of their individual isoforms to bind chitin was studied. Some increase in peroxidase activity was observed in crude extracts in the presence of chitin. Activated peroxidases of some species fell in the fraction not sorbed on chitin and those of other species can bind chitin. Only anionic isoperoxidases from oat (Avena sativa), rice (Oryza sativa), horseradish (Armoracia rusticana), garden radish (Raphanus sativus var. radicula), peanut (Arachis hypogaea), and tobacco (Nicotiana tabacum Link et Otto) were sorbed on chitin. Both anionic and cationic isoforms from pea (Pisum sativum), galega(Galega orientalis), cucumber (Cucumis sativus), and zucchini (Cucurbita pepo L.) were sorbed on chitin. Peroxidase activation under the influence of chitin was correlated to the processes that occur during hypersensitive reaction and lignification of sites, in which pathogenic fungus penetrates into a plant. The role of chitin-specific isoperoxidases in inhibition of fungal growth and connection of this phenomenon with structural characteristics of isoperoxidases are also discussed.

Cytotoxicity and mechanical behavior of chitin-bentonite clay based polyurethane bio-nanocomposites.

PubMed

Zia, Khalid Mahmood; Zuber, Mohammad; Barikani, Mehdi; Hussain, Rizwan; Jamil, Tahir; Anjum, Sohail

2011-12-01

Chitin based polyurethane bio-nanocomposites (PUBNC) were prepared using chitin, Delite HPS bentonite nanoclay enriched in montmorillonite (MMT), 4,4'-diphenylmethane diisocyanate (MDI) and polycaprolactone polyol CAPA 231 (3000 g/mol(-1)). The prepolymers having different concentration of Delite HPS bentonite nanoclay were extended with 2 moles of chitin. The structures of the resulted polymers were determined by FT-IR technique. The effect of nanoclay contents on mechanical properties and in vitro biocompatibility was investigated. The mechanical properties of the synthesized materials were improved with increase in the Delite HPS bentonite nanoclay contents. Optimum mechanical properties were obtained from the PU bio-nanocomposite samples having 4% Delite HPS bentonite nanoclay. The results revealed that the final PU bio-nanocomposite having 2% Delite HPS bentonite nanoclay contents is ideal contenders for surgical threads with on going investigations into their in vitro biocompatibility, non-toxicity, and mechanical properties. Copyright © 2011 Elsevier B.V. All rights reserved.

Preparation and biocompatibility of a chitin nanofiber/gelatin composite film.

PubMed

Ogawa, Yoko; Azuma, Kazuo; Izawa, Hironori; Morimoto, Minoru; Ochi, Kosuke; Osaki, Tomohiro; Ito, Norihiko; Okamoto, Yoshiharu; Saimoto, Hiroyuki; Ifuku, Shinsuke

2017-11-01

The development of chitin-based materials with favorable mechanical properties and biocompatibility is an important research goal owing to the wide-ranging practical applications. In this study, a composite film was prepared using chitin nanofibers and gelatin. The CNF/gelatin composite film was highly viscous and had a fine nanofiber structure. The transmittances indicated high transparency, regardless of nanofiber content. The water content of the CNF/gelatin composite film increased linearly as the gelatin content increased. Although the CNF/gelatin composite film did not induce severe inflammation, it strongly induced fibroblast proliferation, indicating high biocompatibility. Based on these results, the films are suitable for biological applications, e.g., tissue engineering, medicines, and cosmetics. Copyright © 2017 Elsevier B.V. All rights reserved.

Chitin hoops obtained from Ommatoiulus sabulosus (Diplopoda, Julidae) used for bovine serum albumin adsorption.

PubMed

Šatkauskienė, Ingrida; Jarusevičiūtė, Simona; Baublys, Vykintas; Maheta, Mansi; Tubelytė, Vaida

2017-01-01

A new hoop shaped three dimensional chitin was obtained successfully from the body segment of a diplopod species (Ommatoiulus sabulosus) by following the procedure decolorization, demineralization and deproteinization. Purity of the hoop shaped three-dimensional chitin was proved by FT-IR analysis and chitinase digestive test. The important bands for α-chitin such as 1654.2, 1619.7 and 1552cm -1 were found after FT-IR analysis. And the chitinase digestive test revealed the purity of chitin (with digestion rate of 94.7%). SEM analysis showed that the chitin surface consisted of highly porous structure with nanofibers. Thermal stability of the hoop shaped chitin was recorded quite high (DTG max =383°C). The nitrogen, carbon and hydrogen contents of the hoop shaped chitin were determined as 6.81%, 46.23% and 6.43% respectively. And also degree of acetylation (DA) of the chitin indicated the purity with 95.85%. Chitin hoops-BSA interaction was conducted at different pH, protein concentration and contact time. This new type of three-dimensional chitin obtained from the diplopod body segments can find more effective applications in further studies comparing to the conventional dust forms. Copyright © 2016 Elsevier B.V. All rights reserved.

Cloning and characterization of chsD, a chitin synthase-like gene of Aspergillus fumigatus.

PubMed

Mellado, E; Specht, C A; Robbins, P W; Holden, D W

1996-09-15

A chitin synthase-like gene (chsD) was isolated from an Aspergillus fumigatus genomic DNA library. Comparisons with the predicted amino acid sequence from chsD reveals low but significant similarity to chitin synthases, to other N-acetylglucosaminyltransferases (NodC from Rhizopus spp., HasA from Streptococcus spp. and DG42 from vertebrates. A chsD- mutant strain constructed by gene disruption has a 20% reduction in total mycelial chitin content; however, no differences between the wild-type strain and the chsD- strain were found with respect to morphology, chitin synthase activity or virulence in a neutropenic murine model of aspergillosis. The results show that the chsD product has an important but inessential role in the synthesis of chitin in A. fumigatus.

The influence of HCl concentration and demineralization temperature of Atrina pectinata shells on quality of chitin

NASA Astrophysics Data System (ADS)

Nugroho, Intan Lazuardi; Pursetyo, Kustiawan Tri; Masithah, Endang Dewi

2017-02-01

Atrina pectinata is one of shells species widely consumed by people, which means the high consumption will generate the availability of shells in the environment as waste. Chitin can be produced from the shells. Shells contain quite high minerals that it should be demineralized to reduce the mineral content from the shells. This study aimed to determine the effect of HCl concentration and temperature affect chitin characteristics as the result of demineralization process from pen shells. The method based on two steps, there were demineralization and deproteination. This study used Completely Randomized Design (CRD) with two factors, including HCl concentration (2N, 4N, and 6N) and temperature (33°C and 60°C) which consists six combination treatments and three replications. Data was analyzed by using Analysis of Variance (ANOVA) and followed by Duncan's Multiple Range Test. The results showed that interaction of HCl concentration and temperature has significant effect (p<0.05) to ash content of chitin. The use concentration of 6N and 33°C produced the lowest ash content. Characteristics chitin resulted from the treatment of 6N and 33°C produced ash content 25.33% ± 6.82, moisture content 3.67% ± 1.10, yield 0.72% ± 0.12 and protein content 5.86%.

Chitin: 'Forgotten' Source of Nitrogen: From Modern Chitin to Thermally Mature Kerogen: Lessons from Nitrogen Isotope Ratios

USGS Publications Warehouse

Schimmelmann, A.; Wintsch, R.P.; Lewan, M.D.; DeNiro, M.J.

1998-01-01

Chitinous biomass represents a major pool of organic nitrogen in living biota and is likely to have contributed some of the fossil organic nitrogen in kerogen. We review the nitrogen isotope biogeochemistry of chitin and present preliminary results suggesting interaction between kerogen and ammonium during thermal maturation. Modern arthropod chitin may shift its nitrogen isotope ratio by a few per mil depending on the chemical method of chitin preparation, mostly because N-containing non-amino-sugar components in chemically complex chitin cannot be removed quantitatively. Acid hydrolysis of chemically complex chitin and subsequent ion-chromatographic purification of the "deacetylated chitin-monomer" D-glucosamine (in hydrochloride form) provides a chemically well-defined, pure amino-sugar substrate for reproducible, high-precision determination of ??15N values in chitin. ??15N values of chitin exhibited a variability of about one per mil within an individual's exoskeleton. The nitrogen isotope ratio differed between old and new exoskeletons by up to 4 per mil. A strong dietary influence on the ??15N value of chitin is indicated by the observation of increasing ??15N values of chitin from marine crustaceans with increasing trophic level. Partial biodegradation of exoskeletons does not significantly influence ??15N values of remaining, chemically preserved amino sugar in chitin. Diagenesis and increasing thermal maturity of sedimentary organic matter, including chitin-derived nitrogen-rich moieties, result in humic compounds much different from chitin and may significantly change bulk ??15N values. Hydrous pyrolysis of immature source rocks at 330??C in contact with 15N-enriched NH4Cl, under conditions of artificial oil generation, demonstrates the abiogenic incorporation of inorganic nitrogen into carbon-bound nitrogen in kerogen. Not all organic nitrogen in natural, thermally mature kerogen is therefore necessarily derived from original organic matter, but may

Characterization of chitin and chitosan synthesized from red snapper (Lutjanus sp.) scale's waste

NASA Astrophysics Data System (ADS)

Takarina, N. D.; Fanani, A. A.

2017-07-01

Chitin and chitosan are natural biopolymer which are useful for industrial, medical and environmental field. Study about using fish scale sources especially saltwater fish is still limited. Red snapper (Lutjanus sp) is common tropical saltwater fish that known as important source of marine products, particularly in Indonesia. Correspondingly, the consumption of this species has generated significant amount of discarded scale wastes recently and hence can cause adverse impact on the environment. Utilizing the fish scale as alternative sources of chitin and chitosan can be one solution dealing with environmental problem. Therefore, this research aimed to characterize the chitin and chitosan derived from the red snapper scale wastes. Chitin were extracted by deproteination and demineralization while chitosan using deacetylation. Morphology of the chitin and chitosan were analyzed using electron dispersal spectroscopy (EDS) and scanning electron microscope (SEM), while degree of deacetylation using fourier transform infrared spectroscopy (FTIR). Proximate analysis showed that content of moisture, ash, and nitrogen in chitin were 3.20 %, 2.40 %, 0.04 %, respectively while in chitosan were 6.14 %, 1.18 %, 0.03 % respectively. Furthermore, amount of C, O, Na, Al, P and Ca elements were obtained from chitin and chitosan samples by energy dispersed spectroscopy respectively. The degree of deacetylation for both chitin and chitosan showed high value more than 75 %. Hence, by considering the chemical properties of red snapper scales, it confirms that this species is a promising alternative source for both chitin and chitosan.

Chitin-Like Molecules Associate with Cryptococcus neoformans Glucuronoxylomannan To Form a Glycan Complex with Previously Unknown Properties

PubMed Central

Ramos, Caroline L.; Fonseca, Fernanda L.; Rodrigues, Jessica; Guimarães, Allan J.; Cinelli, Leonardo P.; Miranda, Kildare; Nimrichter, Leonardo; Casadevall, Arturo; Travassos, Luiz R.

2012-01-01

In prior studies, we demonstrated that glucuronoxylomannan (GXM), the major capsular polysaccharide of the fungal pathogen Cryptococcus neoformans, interacts with chitin oligomers at the cell wall-capsule interface. The structural determinants regulating these carbohydrate-carbohydrate interactions, as well as the functions of these structures, have remained unknown. In this study, we demonstrate that glycan complexes composed of chitooligomers and GXM are formed during fungal growth and macrophage infection by C. neoformans. To investigate the required determinants for the assembly of chitin-GXM complexes, we developed a quantitative scanning electron microscopy-based method using different polysaccharide samples as inhibitors of the interaction of chitin with GXM. This assay revealed that chitin-GXM association involves noncovalent bonds and large GXM fibers and depends on the N-acetyl amino group of chitin. Carboxyl and O-acetyl groups of GXM are not required for polysaccharide-polysaccharide interactions. Glycan complex structures composed of cryptococcal GXM and chitin-derived oligomers were tested for their ability to induce pulmonary cytokines in mice. They were significantly more efficient than either GXM or chitin oligomers alone in inducing the production of lung interleukin 10 (IL-10), IL-17, and tumor necrosis factor alpha (TNF-α). These results indicate that association of chitin-derived structures with GXM through their N-acetyl amino groups generates glycan complexes with previously unknown properties. PMID:22562469

A carnivorous sundew plant prefers protein over chitin as a source of nitrogen from its traps.

PubMed

Pavlovič, Andrej; Krausko, Miroslav; Adamec, Lubomír

2016-07-01

Carnivorous plants have evolved in nutrient-poor wetland habitats. They capture arthropod prey, which is an additional source of plant growth limiting nutrients. One of them is nitrogen, which occurs in the form of chitin and proteins in prey carcasses. In this study, the nutritional value of chitin and protein and their digestion traits in the carnivorous sundew Drosera capensis L. were estimated using stable nitrogen isotope abundance. Plants fed on chitin derived 49% of the leaf nitrogen from chitin, while those fed on the protein bovine serum albumin (BSA) derived 70% of its leaf nitrogen from this. Moreover, leaf nitrogen content doubled in protein-fed in comparison to chitin-fed plants indicating that the proteins were digested more effectively in comparison to chitin and resulted in significantly higher chlorophyll contents. The surplus chlorophyll and absorbed nitrogen from the protein digestion were incorporated into photosynthetic proteins - the light harvesting antennae of photosystem II. The incorporation of insect nitrogen into the plant photosynthetic apparatus may explain the increased rate of photosynthesis and plant growth after feeding. This general response in many genera of carnivorous plants has been reported in many previous studies. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Changes in physicochemical properties of chitin at developmental stages (larvae, pupa and adult) of Vespa crabro (wasp).

PubMed

Kaya, Murat; Sofi, Karwan; Sargin, Idris; Mujtaba, Muhammad

2016-07-10

It is already known that chitin in a single organism can exhibit huge differences depending on the functions it serves in different body parts, but the alterations in the characteristics of chitin in course of developmental stages of an organism still remain unknown. This study presents findings on how chitin matrix is changing physicochemically through discrete morphological stages - larva, pupa and adult - of an insect (Vespa crabro). Chitin content of the organisms were found to increase gradually as the organism grew; 2.1, 6.2 and 10.3%, with a dramatic increase in chitin deposition (nearly 3 folds) during the instar from larva to pupa. Enzymatic digestion test demonstrated that chitin isolates were close to pure. Chitin isolates were also subjected to thermal pyrolysis and no variations were observed in the thermal stability of the samples. However, it was observed that surface characteristics of chitin changed greatly as the insect grew. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chitin nanowhisker-supported sulfonated poly(ether sulfone) proton exchange for fuel cell applications.

PubMed

Zhang, Chan; Zhuang, Xupin; Li, Xiaojie; Wang, Wei; Cheng, Bowen; Kang, Weimin; Cai, Zhanjun; Li, Mengqin

2016-04-20

To balance the relationship among proton conductivity and mechanic strength of sulfonated poly(ether sulfone) (SPES) membrane, chitin nanowhisker-supported nanocomposite membranes were prepared by incorporating whiskers into SPES. The as-prepared chitin whiskers were prepared by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) mediated oxidation of α-chitin from crab shells. The structure and properties of the composite membranes were examined as proton exchange membrane (PEM). Results showed that chitin nanowhiskers were dispersed incompactly in the SPES matrix. Thermal stability, mechanical properties, water uptake and proton conductivity of the nanocomposite films were improved from those of the pure SPES film with increasing whisker content, which ascribed to strong interactions between whiskers and between SPES molecules and chitin whiskers via hydrogen bonding. These indicated that composition of filler and matrix got good properties and whisker-supported membranes are promising materials for PEM. Copyright © 2015 Elsevier Ltd. All rights reserved.

The hard parts (trophi) of the rotifer mastax do contain chitin: evidence from studies on Brachionus plicatilis.

PubMed

Klusemann, J; Kleinow, W; Peters, W

1990-01-01

The jaws (trophi) of the rotifer Brachionus plicatilis are soluble in strong acids but are resistant to long treatments by strong alkali. They show the same buoyant density as chitin and also as the chitin-containing layers of rotifer egg-shells. The presence of chitin in these structures was confirmed using the following techniques: chitosan-tests, thin-layer chromatography of trophi-hydrolysates which revealed glucosamine, by dissolving trophi with chitinase and electron microscopic WGA/gold-labelling. The content of chitin in the trophi was estimated by two different methods to be approx. 64% (50-75%).

chs-4, a class IV chitin synthase gene from Neurospora crassa.

PubMed

Din, A B; Specht, C A; Robbins, P W; Yarden, O

1996-02-05

In Saccharomyces cerevisiae, most of the cellular chitin is produced by chitin synthase III, which requires the product encoded by the CSD2/CAL1/DIT101/KT12 gene. We have identified, isolated and structurally characterized as CSD2/CAL1/DIT101/KT12 homologue in the filamentous ascomycete Neurospora crassa and have used a "reverse genetics" approach to determine its role in vivo. The yeast gene was used as a heterologous probe for the isolation of a N. crassa gene(designated chs-4) encoding a polypeptide belonging to a class of chitin synthases which we have designated class IV. The predicted polypeptide encoded by this gene is highly similar to those of S. cerevisiae and Candida albicans. N. crassa strains in which chs-4 had been inactivated by the Repeat-Induced point mutation (RIP) process grew and developed in a normal manner under standard growth conditions. However, when grown in the presence of sorbose (a carbon source which induces morphological changes accompanied by elevated chitin content), chitin levels in the chs-4RIP strain were significantly lower than those observed in the wild type. We suggest that CHS4 may serve as an auxiliary enzyme in N. crassa and that, in contrast to yeasts, it is possible that filamentous fungi may have more than one class IV chitin synthase.

Heterologous Expression and Characterization of a Novel Chitinase (ChiEn1) from Coprinopsis cinerea and its Synergism in the Degradation of Chitin.

PubMed

Niu, Xin; Zhou, Jiang-Sheng; Wang, Yan-Xin; Liu, Cui-Cui; Liu, Zhong-Hua; Yuan, Sheng

2017-08-16

Chitinase ChiEn1 did not hydrolyze insoluble chitin but showed hydrolysis and transglycosylation activities toward chitin-oligosaccharides. Interestingly, the addition of ChiEn1 increased the amount of reducing sugars released from chitin powder by endochitinase ChiIII by 105.0%, and among the released reducing sugars the amount of (GlcNAc) 2 was increased by 149.5%, whereas the amount of GlcNAc was decreased by 10.3%. The percentage of GlcNAc in the products of chitin powder with the combined ChiIII and ChiEn1 was close to that in the products of chitin-oligosaccharides with ChiEn1, rather than that with ChiIII. These results indicate that chitin polymers are first degraded into chitin oligosaccharides by ChiIII and the latter are further degraded to monomers and dimers by ChiEn1, and the synergistic action of ChiEn1 and ChiIII is involved in the efficient degradation of chitin in cell walls during pileus autolysis. The structure modeling explores the molecular base of ChiEn1 action.

Chitin receptor CERK1 links salt stress and chitin-triggered innate immunity in Arabidopsis.

PubMed

Espinoza, Catherine; Liang, Yan; Stacey, Gary

2017-03-01

In nature, plants need to respond to multiple environmental stresses that require the involvement and fine-tuning of different stress signaling pathways. Cross-tolerance, in which plants pre-treated with chitin (a fungal microbe-associated molecular pattern) have improved salt tolerance, was observed in Arabidopsis, but is not well understood. Here, we show a unique link between chitin and salt signaling mediated by the chitin receptor CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1). Transcriptome analysis revealed that salt stress-induced genes are highly correlated with chitin-induced genes, although this was not observed with other microbe-associated molecular patterns (MAMPs) or with other abiotic stresses. The cerk1 mutant was more susceptible to NaCl than was the wild type. cerk1 plants had an irregular increase of cytosolic calcium ([Ca 2+ ] cyt ) after NaCl treatment. Bimolecular fluorescence complementation (BiFC) and co-immunoprecipitation experiments indicated that CERK1 physically interacts with ANNEXIN 1 (ANN1), which was reported to form a calcium-permeable channel that contributes to the NaCl-induced [Ca 2+ ] cyt signal. In turn, ann1 mutants showed elevated chitin-induced rapid responses. In short, molecular components previously shown to function in chitin or salt signaling physically interact and intimately link the downstream responses to fungal attack and salt stress. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Surface morphology of chitin highly related with the isolated body part of butterfly (Argynnis pandora).

PubMed

Kaya, Murat; Bitim, Betül; Mujtaba, Muhammad; Koyuncu, Turgay

2015-11-01

This study was conducted to understand the differences in the physicochemical properties of chitin samples isolated from the wings and the other body parts except the wings (OBP) of a butterfly species (Argynnis pandora). The same isolation method was used for obtaining chitin specimens from both types of body parts. The chitin content of the wings (22%) was recorded as being much higher than the OBP (8%). The extracted chitin samples were characterized via FT-IR, TGA, XRD, SEM, and elemental analysis techniques. Results of these characterizations revealed that the chitins from both structures (wings and OBP) were very similar, except for their surface morphologies. SEM results demonstrated one type of surface morphology for the wings and four different surface morphologies for the OBP. Therefore, it can be hypothesized that the surface morphology of the chitin is highly related with the body part. Copyright © 2015 Elsevier B.V. All rights reserved.

The transcription factor Rap1p is required for tolerance to cell-wall perturbing agents and for cell-wall maintenance in Saccharomyces cerevisiae.

PubMed

Azad, Gajendra Kumar; Singh, Vikash; Baranwal, Shivani; Thakare, Mayur Jankiram; Tomar, Raghuvir S

2015-01-02

Yeast repressor activator protein (Rap1p) is involved in genomic stability and transcriptional regulation. We explored the function of Rap1p in yeast physiology using Rap1p truncation mutants. Our results revealed that the N-terminal truncation of Rap1p (Rap1ΔN) leads to hypersensitivity towards elevated temperature and cell-wall perturbing agents. Cell wall analysis showed an increase in the chitin and glucan content in Rap1ΔN cells as compared with wild type cells. Accordingly, mutant cells had a twofold thicker cell wall, as observed by electron microscopy. Furthermore, Rap1ΔN cells had increased levels of phosphorylated Slt2p, a MAP kinase of the cell wall integrity pathway. Mutant cells also had elevated levels of cell wall integrity response transcripts. Taken together, our findings suggest a connection between Rap1p and cell wall homeostasis. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Development of Coprocessed Chitin-Calcium Carbonate as Multifunctional Tablet Excipient for Direct Compression.

PubMed

Chaheen, Mohammad; Sanchez-Ballester, Noelia M; Bataille, Bernard; Yassine, Ahmad; Belamie, Emmanuel; Sharkawi, Tahmer

2018-04-24

Owing to the increasing interest in multifunctional excipients for tableting, coprocessing of individual excipients is regularly used to produce excipients of improved multifunctionality superior to individual excipients or their physical mix. The use of chitin as an excipient in tablet formulation is limited because of certain drawbacks such as poor flowability and low true density. The objective of this work is to improve these properties through coprocessing of chitin with calcium carbonate (CaCO 3 ) by precipitating CaCO 3 on chitin particles using different methods. In addition, optimization of the coprocessed chitin was carried out to improve the excipient's properties. Physicochemical (CaCO 3 content, true density, X-ray diffraction, infrared spectroscopy, and scanning electron microscopy) and functional testing (swelling force, flowability, tensile strength, deformation mechanism, and disintegration time) were used to characterize the coprocessed product. Results showed that the calcite CaCO 3 polymorph is precipitated on the chitin surface and that it interacts with chitin at carbonyl- and amide-group level. In addition, the coprocessed excipient has an improved true density and powder flowability, with CaCO 3 forming single layer on the chitin particles surface. Tableting studies showed that the coprocessed powder exhibited an intermediate deformation behavior between CaCO 3 (most brittle) and chitin (most plastic). Tablets showed acceptable tensile strength and rapid disintegration (2-4 s). These results show the potential use of coprocessed chitin-CaCO 3 as a multifunctional excipient for fast disintegration of tablets produced by direct compression. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Fabrication of optically transparent chitin nanocomposites

NASA Astrophysics Data System (ADS)

Shams, M. Iftekhar; Ifuku, Shinsuke; Nogi, Masaya; Oku, Takeshi; Yano, Hiroyuki

2011-02-01

This paper demonstrates the preparation of chitin nanofibers from crab shells using a simple mechanical treatment. The nanofibers are small enough to retain the transparency of neat acrylic resin. Possessing hydroxyl and amine/ N-acetyl functionalities, water suspension of chitin nanofibers was vacuum-filtered 9 times faster than cellulose nanofibers to prepare a nanofiber sheet of 90 mm in diameter. This is a prominent advantage of chitin nanofibers over cellulose nanofibers in terms of commercial application. Interestingly, chitin acrylic resin films exhibited much higher transparency than cellulose acrylic resin films owing to the close affinity between less hydrophilic chitin and hydrophobic resin. Furthermore, the incorporation of chitin nanofibers contributes to the significant improvement of the thermal expansion and mechanical properties of the neat acrylic resin. The properties of high light transmittance and low thermal expansion make chitin nanocomposites promising candidates for the substrate in a continuous roll-to-roll process in the manufacturing of various optoelectronic devices such as flat panel displays, bendable displays, and solar cells.

A LysM receptor-like kinase plays a critical role in chitin signaling and fungal resistance in Arabidopsis.

PubMed

Wan, Jinrong; Zhang, Xue-Cheng; Neece, David; Ramonell, Katrina M; Clough, Steve; Kim, Sung-Yong; Stacey, Minviluz G; Stacey, Gary

2008-02-01

Chitin, a polymer of N-acetyl-d-glucosamine, is found in fungal cell walls but not in plants. Plant cells can perceive chitin fragments (chitooligosaccharides) leading to gene induction and defense responses. We identified a LysM receptor-like protein (LysM RLK1) required for chitin signaling in Arabidopsis thaliana. The mutation in this gene blocked the induction of almost all chitooligosaccharide-responsive genes and led to more susceptibility to fungal pathogens but had no effect on infection by a bacterial pathogen. Additionally, exogenously applied chitooligosaccharides enhanced resistance against both fungal and bacterial pathogens in the wild-type plants but not in the mutant. Together, our data indicate that LysM RLK1 is essential for chitin signaling in plants (likely as part of the receptor complex) and is involved in chitin-mediated plant innate immunity. The LysM RLK1-mediated chitin signaling pathway is unique, but it may share a conserved downstream pathway with the FLS2/flagellin- and EFR/EF-Tu-mediated signaling pathways. Additionally, our work suggests a possible evolutionary relationship between the chitin and Nod factor perception mechanisms due to the similarities between their potential receptors and between the signal molecules perceived by them.

RNA interference of chitin synthase genes inhibits chitin biosynthesis and affects larval performance in Leptinotarsa decemlineata (Say).

PubMed

Shi, Ji-Feng; Mu, Li-Li; Chen, Xu; Guo, Wen-Chao; Li, Guo-Qing

2016-01-01

Dietary introduction of bacterially expressed double-stranded RNA (dsRNA) has great potential for management of Leptinotarsa decemlineata . Identification of the most attractive candidate genes for RNA interference (RNAi) is the first step. In the present paper, three complete chitin synthase cDNA sequences ( LdChSAa , LdChSAb and LdChSB ) were cloned. LdChSAa and LdChSAb , two splicing variants of LdChSA gene, were highly expressed in ectodermally-derived epidermal cells forming epidermis, trachea, foregut and hindgut, whereas LdChSB was mainly transcribed in midgut cells. Feeding bacterially expressed ds ChSA (derived from a common fragment of LdChSAa and LdChSAb ), ds ChSAa , ds ChSAb and ds ChSB in the second- and fourth-instar larvae specifically knocked down their target mRNAs. RNAi of LdChSAa + LdChSAb and LdChSAa lowered chitin contents in whole body and integument samples, and thinned tracheal taenidia. The resulting larvae failed to ecdyse, pupate, or emerge as adults. Comparably, knockdown of LdChSAb mainly affected pupal-adult molting. The LdChSAb RNAi pupae did not completely shed the old larval exuviae, which caused failure of adult emergence. In contrast, silencing of LdChSB significantly reduced foliage consumption, decreased chitin content in midgut sample, damaged midgut peritrophic matrix, and retarded larval growth. As a result, the development of the LdChSB RNAi hypomorphs was arrested. Our data reveal that these LdChS s are among the effective candidate genes for an RNAi-based control strategy against L. decemlineata .

Architecture and Biosynthesis of the Saccharomyces cerevisiae Cell Wall

PubMed Central

Orlean, Peter

2012-01-01

The wall gives a Saccharomyces cerevisiae cell its osmotic integrity; defines cell shape during budding growth, mating, sporulation, and pseudohypha formation; and presents adhesive glycoproteins to other yeast cells. The wall consists of β1,3- and β1,6-glucans, a small amount of chitin, and many different proteins that may bear N- and O-linked glycans and a glycolipid anchor. These components become cross-linked in various ways to form higher-order complexes. Wall composition and degree of cross-linking vary during growth and development and change in response to cell wall stress. This article reviews wall biogenesis in vegetative cells, covering the structure of wall components and how they are cross-linked; the biosynthesis of N- and O-linked glycans, glycosylphosphatidylinositol membrane anchors, β1,3- and β1,6-linked glucans, and chitin; the reactions that cross-link wall components; and the possible functions of enzymatic and nonenzymatic cell wall proteins. PMID:23135325

Chitin Liquid-Crystal-Templated Oxide Semiconductor Aerogels.

PubMed

Chau, Trang The Lieu; Le, Dung Quang Tien; Le, Hoa Thi; Nguyen, Cuong Duc; Nguyen, Long Viet; Nguyen, Thanh-Dinh

2017-09-13

Chitin nanocrystals have been used as a liquid crystalline template to fabricate layered oxide semiconductor aerogels. Anisotropic chitin liquid crystals are transformed to sponge-like aerogels by hydrothermally cross-linked gelation and lyophilization-induced solidification. The hydrothermal gelation of chitin aqueous suspensions then proceeds with peroxotitanate to form hydrogel composites that recover to form aerogels after freeze-drying. The homogeneous peroxotitanate/chitin composites are calcined to generate freestanding titania aerogels that exhibit the nanostructural integrity of layered chitin template. Our extended investigations show that coassembling chitin nanocrystals with other metal-based precursors also yielded semiconductor aerogels of perovskite BaTiO 3 and CuO x nanocrystals. The potential of these materials is great to investigate these chitin sponges for biomedicine and these semiconductor aerogels for photocatalysis, gas sensing, and other applications. Our results present a new aerogel templating method of highly porous, ultralight materials with chitin liquid crystals.

High similarity in physicochemical properties of chitin and chitosan from nymphs and adults of a grasshopper.

PubMed

Erdogan, Sevil; Kaya, Murat

2016-08-01

This is the first study to explain the differences in the physicochemical properties of chitin and chitosan obtained from the nymphs and adults of Dociostaurus maroccanus using the same method. Fourier transform infrared spectroscopy, thermogravimetric analysis and x-ray diffraction analysis results demonstrated that the chitins from both the adults and nymphs were in the α-form. The chitin contents of the adults (14%) and nymphs (12%) were of the same order of magnitude. The crystalline index values of chitins from the adult and nymph grasshoppers were 71% and 74%, respectively. Thermal stabilities of the chitins and chitosans from adult and nymph grasshoppers were close to each other. Both the adult (7.2kDa) and nymph (5.6kDa) chitosans had low molar masses. Environmental scanning electron microscopy revealed that the surface morphologies of both chitins consisted of nanofibers and nanopores together, and they were very similar to each other. Consequently, it was determined that the physicochemical properties of the chitins and chitosans from adults and nymphs of D. maroccanus were not very different, so it can be hypothesized that the development of the chitin structure in the nymph has almost been completed and the nymph chitin has the same characteristics as the adult. Copyright © 2016 Elsevier B.V. All rights reserved.

Cell wall α-1,3-glucan prevents α-amylase adsorption onto fungal cell in submerged culture of Aspergillus oryzae.

PubMed

Zhang, Silai; Sato, Hiroki; Ichinose, Sakurako; Tanaka, Mizuki; Miyazawa, Ken; Yoshimi, Akira; Abe, Keietsu; Shintani, Takahiro; Gomi, Katsuya

2017-07-01

We have previously reported that α-amylase (Taka-amylase A, TAA) activity disappears in the later stage of submerged Aspergillus oryzae culture as a result of TAA adsorption onto the cell wall. Chitin, one of the major components of the cell wall, was identified as a potential factor that facilitates TAA adsorption. However, TAA adsorption only occurred in the later stage of cultivation, although chitin was assumed to be sufficiently abundant in the cell wall regardless of the submerged culture period. This suggested the presence a factor that inhibits TAA adsorption to the cell wall in the early stage of cultivation. In the current study, we identified α-1,3-glucan as a potential inhibiting factor for TAA adsorption. We constructed single, double, and triple disruption mutants of three α-1,3-glucan synthase genes (agsA, agsB, and agsC) in A. oryzae. Growth characteristics and cell wall component analysis of these disruption strains showed that AgsB plays a major role in α-1,3-glucan synthesis. In the ΔagsB mutant, TAA was adsorbed onto the mycelium in all stages of cultivation (early and later), and the ΔagsB mutant cell walls had a significantly high capacity for TAA adsorption. Moreover, the α-1,3-glucan content of the cell wall prepared from the wild-type strain in the later stage of cultivation was markedly reduced compared with that in the early stage. These results suggest that α-1,3-glucan is a potential inhibiting factor for TAA adsorption onto the cell wall component, chitin, in the early stage of submerged culture in A. oryzae. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

The kinase LYK5 is a major chitin receptor in Arabidopsis and forms a chitin-induced complex with related kinase CERK1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Yangrong; Liang, Yan; Tanaka, Kiwamu

Chitin is a fungal microbe-associated molecular pattern recognized in Arabidopsis by a lysin motif receptor kinase (LYK), AtCERK1. Previous research suggested that AtCERK1 is the major chitin receptor and mediates chitin-induced signaling through homodimerization and phosphorylation. However, the reported chitin binding affinity of AtCERK1 is quite low, suggesting another receptor with high chitin binding affinity might be present. Here, we propose that AtLYK5 is the primary chitin receptor in Arabidopsis. Mutations in AtLYK5 resulted in a significant reduction in chitin response. AtLYK5 shares overlapping function with AtLYK4 and, therefore, Atlyk4/Atlyk5-2 double mutants show a complete loss of chitin response. AtLYK5more » interacts with AtCERK1 in a chitin-dependent manner. Chitin binding to AtLYK5 is indispensable for chitin-induced AtCERK1 phosphorylation. AtLYK5 binds chitin at a much higher affinity than AtCERK1. The data suggest that AtLYK5 is the primary receptor for chitin, forming a chitin inducible complex with AtCERK1 to induce plant immunity.« less

The kinase LYK5 is a major chitin receptor in Arabidopsis and forms a chitin-induced complex with related kinase CERK1

DOE PAGES

Cao, Yangrong; Liang, Yan; Tanaka, Kiwamu; ...

2014-10-23

Chitin is a fungal microbe-associated molecular pattern recognized in Arabidopsis by a lysin motif receptor kinase (LYK), AtCERK1. Previous research suggested that AtCERK1 is the major chitin receptor and mediates chitin-induced signaling through homodimerization and phosphorylation. However, the reported chitin binding affinity of AtCERK1 is quite low, suggesting another receptor with high chitin binding affinity might be present. Here, we propose that AtLYK5 is the primary chitin receptor in Arabidopsis. Mutations in AtLYK5 resulted in a significant reduction in chitin response. AtLYK5 shares overlapping function with AtLYK4 and, therefore, Atlyk4/Atlyk5-2 double mutants show a complete loss of chitin response. AtLYK5more » interacts with AtCERK1 in a chitin-dependent manner. Chitin binding to AtLYK5 is indispensable for chitin-induced AtCERK1 phosphorylation. AtLYK5 binds chitin at a much higher affinity than AtCERK1. The data suggest that AtLYK5 is the primary receptor for chitin, forming a chitin inducible complex with AtCERK1 to induce plant immunity.« less

Defense Against Pathogens: Structural Insights into the Mechanism of Chitin Induced Activation of Innate Immunity.

PubMed

Squeglia, Flavia; Berisio, Rita; Shibuya, Naoto; Kaku, Hanae

2017-11-24

Pattern recognition receptors on the plant cell surface mediate the recognition of microbe-associated molecular patterns, in a process which activates downstream immune signaling. These receptors are plasma membrane-localized kinases which need to be autophosphorylated to activate downstream responses. Perception of attacks from fungi occurs through recognition of chitin, a polymer of an N-acetylglucosamine which is a characteristic component of the cell walls of fungi. This process is regulated in Arabidopsis by chitin elicitor receptor kinase CERK1. A more complex process characterizes rice, in which regulation of chitin perception is operated by a complex composed of OsCERK1, a homolog of CERK1, and the chitin elicitor binding protein OsCEBiP. Recent literature has provided a mechanistic description of the complex regulation of activation of innate immunity in rice and an advance in the structural description of molecular players involved in this process. This review describes the current status of the understanding of molecular events involved in innate immunity activation in rice. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Squid pen-inspired chitinous functional materials: Hierarchical chitin fibers by centrifugal jet-spinning and transparent chitin fiber-reinforced composite

NASA Astrophysics Data System (ADS)

Jeong, Seung-Hwan; Kim, Joong-Kwon; Lim, Young-Woo; Hwang, Hyun-Bin; Kwon, Hee-Young; Bae, Byeong-Soo; Jin, Jungho

2018-01-01

Here, inspired by the fibrous composite structure of a squid pen, we introduce hierarchical chitin fibers (herein, termed "Chiber") and their transparent composites and demonstrate the potential of these chitinous functional materials as a sustainable separation-membrane and reinforcing filler for composites. We employ a centrifugal jet-spinning process to fabricate Chiber with aligned chitin nanofibrillar architectures, for which we discuss the processing-morphology relationship. A nonwoven fiber-mat made of Chiber exhibits excellent adsorbing performance for a toxic ionic dye (Congo Red), and has a low coefficient of thermal expansion comparable to that of glass fibers. Finally, we demonstrate a squid pen-mimetic transparent composite using Chiber and investigate its optical property.

Synthesis and physicochemical characterization of chitin dihexanoate--A new biocompatible chitin derivative--In comparison to chitin dibutyrate.

PubMed

Skołucka-Szary, Karolina; Ramięga, Aleksandra; Piaskowska, Wanda; Janicki, Bartosz; Grala, Magdalena; Rieske, Piotr; Bartczak, Zbigniew; Piaskowski, Sylwester

2016-03-01

Chitin dihexanoate (DHCH) is the novel biocompatible and technologically friendly highly substituted chitin diester. Here we described optimization of DHCH and chitin dibutyrate (dibutyryl chitin, DBC) synthesis conditions (temperature and reaction time) to obtain desired polymers with high reaction yield, high substitution degree (close to 2) and appropriately high molecular weights. A two-step procedure, employing acidic anhydrides (hexanoic or butyric anhydride) as the acylation agent and methanesulfonic acid both as the catalyst and the reaction medium, was applied. Chemical structures of DBC and DHCH were confirmed by NMR ((1)H and (13)C) and IR investigations. Mechanical properties, thermogravimetric analysis, differential scanning calorimetry and biocompatibility (Neutral red uptake assay, Skin Sensitization and Irritation Tests) were assessed. Both polymers proved highly biocompatible (non-cytotoxic in vitro, non-irritating and non-allergic to skin) and soluble in several organic solvents (dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, acetone, ethanol and others). It is worth emphasizing that DHCH and DBC can be easily processed by solvent casting method and the salt-leaching method, what gives the opportunity to prepare highly porous structures, which can be further successfully applied as the material for wound dressings and scaffolds for tissue engineering. Copyright © 2015 Elsevier B.V. All rights reserved.

Cell wall of pathogenic yeasts and implications for antimycotic therapy.

PubMed

Cassone, A

1986-01-01

Yeast cell wall is a complex, multilayered structure where amorphous, granular and fibrillar components interact with each other to confer both the specific cell shape and osmotic protection against lysis. Thus it is widely recognized that as is the case with bacteria, yeast cell wall is a major potential target for selective chemotherapeutic drugs. Despite intensive research, very few such drugs have been discovered and none has found substantial application in human diseases to date. Among the different cell wall components, beta-glucan and chitin are the fibrillar materials playing a fundamental role in the overall rigidity and resistance of the wall. Inhibition of the metabolism of these polymers, therefore, should promptly lead to lysis. This indeed occurs and aculeacin, echinocandin and polyoxins are examples of agents producing such an action. Particular attention should be focused on chitin synthesis. Although quantitatively a minor cell wall component, chitin is important in the mechanism of dimorphic transition, especially in Candida albicans, a major human opportunistic pathogen. This transition is associated with increased invasiveness and general virulence of the fungus. Yeast cell wall may also limit the effect of antifungals which owe their action to disturbance of the cytoplasmic membrane or of cell metabolism. Indeed, the cell wall may hinder access to the cell interior both under growing conditions and, particularly, during cell ageing in the stationary phase, when important structural changes occur in the cell wall due to unbalanced wall growth (phenotypic drug resistance).

Structural and Functional Analysis of a Lytic Polysaccharide Monooxygenase Important for Efficient Utilization of Chitin in Cellvibrio japonicus*

PubMed Central

Forsberg, Zarah; Nelson, Cassandra E.; Dalhus, Bjørn; Mekasha, Sophanit; Loose, Jennifer S. M.; Crouch, Lucy I.; Røhr, Åsmund K.; Gardner, Jeffrey G.; Eijsink, Vincent G. H.; Vaaje-Kolstad, Gustav

2016-01-01

Cellvibrio japonicus is a Gram-negative soil bacterium that is primarily known for its ability to degrade plant cell wall polysaccharides through utilization of an extensive repertoire of carbohydrate-active enzymes. Several putative chitin-degrading enzymes are also found among these carbohydrate-active enzymes, such as chitinases, chitobiases, and lytic polysaccharide monooxygenases (LPMOs). In this study, we have characterized the chitin-active LPMO, CjLPMO10A, a tri-modular enzyme containing a catalytic family AA10 LPMO module, a family 5 chitin-binding module, and a C-terminal unclassified module of unknown function. Characterization of the latter module revealed tight and specific binding to chitin, thereby unraveling a new family of chitin-binding modules (classified as CBM73). X-ray crystallographic elucidation of the CjLPMO10A catalytic module revealed that the active site of the enzyme combines structural features previously only observed in either cellulose or chitin-active LPMO10s. Analysis of the copper-binding site by EPR showed a signal signature more similar to those observed for cellulose-cleaving LPMOs. The full-length LPMO shows no activity toward cellulose but is able to bind and cleave both α- and β-chitin. Removal of the chitin-binding modules reduced LPMO activity toward α-chitin compared with the full-length enzyme. Interestingly, the full-length enzyme and the individual catalytic LPMO module boosted the activity of an endochitinase equally well, also yielding similar amounts of oxidized products. Finally, gene deletion studies show that CjLPMO10A is needed by C. japonicus to obtain efficient growth on both purified chitin and crab shell particles. PMID:26858252

Structural and Functional Analysis of a Lytic Polysaccharide Monooxygenase Important for Efficient Utilization of Chitin in Cellvibrio japonicus.

PubMed

Forsberg, Zarah; Nelson, Cassandra E; Dalhus, Bjørn; Mekasha, Sophanit; Loose, Jennifer S M; Crouch, Lucy I; Røhr, Åsmund K; Gardner, Jeffrey G; Eijsink, Vincent G H; Vaaje-Kolstad, Gustav

2016-04-01

Cellvibrio japonicusis a Gram-negative soil bacterium that is primarily known for its ability to degrade plant cell wall polysaccharides through utilization of an extensive repertoire of carbohydrate-active enzymes. Several putative chitin-degrading enzymes are also found among these carbohydrate-active enzymes, such as chitinases, chitobiases, and lytic polysaccharide monooxygenases (LPMOs). In this study, we have characterized the chitin-active LPMO,CjLPMO10A, a tri-modular enzyme containing a catalytic family AA10 LPMO module, a family 5 chitin-binding module, and a C-terminal unclassified module of unknown function. Characterization of the latter module revealed tight and specific binding to chitin, thereby unraveling a new family of chitin-binding modules (classified as CBM73). X-ray crystallographic elucidation of theCjLPMO10A catalytic module revealed that the active site of the enzyme combines structural features previously only observed in either cellulose or chitin-active LPMO10s. Analysis of the copper-binding site by EPR showed a signal signature more similar to those observed for cellulose-cleaving LPMOs. The full-length LPMO shows no activity toward cellulose but is able to bind and cleave both α- and β-chitin. Removal of the chitin-binding modules reduced LPMO activity toward α-chitin compared with the full-length enzyme. Interestingly, the full-length enzyme and the individual catalytic LPMO module boosted the activity of an endochitinase equally well, also yielding similar amounts of oxidized products. Finally, gene deletion studies show thatCjLPMO10A is needed byC. japonicusto obtain efficient growth on both purified chitin and crab shell particles. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

The kinase LYK5 is a major chitin receptor in Arabidopsis and forms a chitin-induced complex with related kinase CERK1

DOE PAGES

Cao, Yangrong; Liang, Yan; Tanaka, Kiwamu; ...

2014-10-23

Chitin is a fungal microbe-associated molecular pattern (MAMP) that is recognized in Arabidopsis by a lysin motif receptor kinase (LYK), AtCERK1. Previous research suggested that AtCERK1 is the major chitin receptor in plants and mediates chitin-induced signaling through homodimerization and phosphorylation. However, the reported chitin binding affinity of AtCERK1 is quite low, suggesting another receptor with high chitin binding affinity might be present. Here, we propose that AtLYK5 is the primary chitin receptor in Arabidopsis. Mutations in AtLYK5 resulted in a significant reduction in the plant chitin response. However, AtLYK5 shares overlapping function with AtLYK4 and, therefore, only AtLYK4/AtLYK5-2 doublemore » mutants show a complete loss of chitin response. AtLYK5 interacts with AtCERK1 in a chitin-dependent manner. Chitin binding to AtLYK5 is indispensable for chitin-induced AtCERK1 phosphorylation. AtLYK5 binds chitin at a much higher affinity than AtCERK1. Furthermore, the data suggest that AtLYK5 is the primary plant receptor for chitin, forming a chitin inducible complex with AtCERK1 to induce plant innate immunity.« less

The kinase LYK5 is a major chitin receptor in Arabidopsis and forms a chitin-induced complex with related kinase CERK1

PubMed Central

Cao, Yangrong; Liang, Yan; Tanaka, Kiwamu; Nguyen, Cuong T; Jedrzejczak, Robert P; Joachimiak, Andrzej; Stacey, Gary

2014-01-01

Chitin is a fungal microbe-associated molecular pattern recognized in Arabidopsis by a lysin motif receptor kinase (LYK), AtCERK1. Previous research suggested that AtCERK1 is the major chitin receptor and mediates chitin-induced signaling through homodimerization and phosphorylation. However, the reported chitin binding affinity of AtCERK1 is quite low, suggesting another receptor with high chitin binding affinity might be present. Here, we propose that AtLYK5 is the primary chitin receptor in Arabidopsis. Mutations in AtLYK5 resulted in a significant reduction in chitin response. However, AtLYK5 shares overlapping function with AtLYK4 and, therefore, Atlyk4/Atlyk5-2 double mutants show a complete loss of chitin response. AtLYK5 interacts with AtCERK1 in a chitin-dependent manner. Chitin binding to AtLYK5 is indispensable for chitin-induced AtCERK1 phosphorylation. AtLYK5 binds chitin at a much higher affinity than AtCERK1. The data suggest that AtLYK5 is the primary receptor for chitin, forming a chitin inducible complex with AtCERK1 to induce plant immunity. DOI: http://dx.doi.org/10.7554/eLife.03766.001 PMID:25340959

The kinase LYK5 is a major chitin receptor in Arabidopsis and forms a chitin-induced complex with related kinase CERK1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Yangrong; Liang, Yan; Tanaka, Kiwamu

Chitin is a fungal microbe-associated molecular pattern (MAMP) that is recognized in Arabidopsis by a lysin motif receptor kinase (LYK), AtCERK1. Previous research suggested that AtCERK1 is the major chitin receptor in plants and mediates chitin-induced signaling through homodimerization and phosphorylation. However, the reported chitin binding affinity of AtCERK1 is quite low, suggesting another receptor with high chitin binding affinity might be present. Here, we propose that AtLYK5 is the primary chitin receptor in Arabidopsis. Mutations in AtLYK5 resulted in a significant reduction in the plant chitin response. However, AtLYK5 shares overlapping function with AtLYK4 and, therefore, only AtLYK4/AtLYK5-2 doublemore » mutants show a complete loss of chitin response. AtLYK5 interacts with AtCERK1 in a chitin-dependent manner. Chitin binding to AtLYK5 is indispensable for chitin-induced AtCERK1 phosphorylation. AtLYK5 binds chitin at a much higher affinity than AtCERK1. Furthermore, the data suggest that AtLYK5 is the primary plant receptor for chitin, forming a chitin inducible complex with AtCERK1 to induce plant innate immunity.« less

Umchs5, a gene coding for a class IV chitin synthase in Ustilago maydis.

PubMed

Xoconostle-Cázares, B; Specht, C A; Robbins, P W; Liu, Y; León, C; Ruiz-Herrera, J

1997-12-01

A fragment corresponding to a conserved region of a fifth gene coding for chitin synthase in the plant pathogenic fungus Ustilago maydis was amplified by means of the polymerase chain reaction (PCR). The amplified fragment was utilized as a probe for the identification of the whole gene in a genomic library of the fungus. The predicted gene product of Umchs5 has highest similarity with class IV chitin synthases encoded by the CHS3 genes from Saccharomyces cerevisiae and Candida albicans, chs-4 from Neurospora crassa, and chsE from Aspergillus nidulans. Umchs5 null mutants were constructed by substitution of most of the coding sequence with the hygromycin B resistance cassette. Mutants displayed significant reduction in growth rate, chitin content, and chitin synthase activity, specially in the mycelial form. Virulence to corn plantules was also reduced in the mutants. PCR was also used to obtain a fragment of a sixth chitin synthase, Umchs6. It is suggested that multigenic control of chitin synthesis in U. maydis operates as a protection mechanism for fungal viability in which the loss of one activity is partially compensated by the remaining enzymes. Copyright 1997 Academic Press.

N-acetylglucosamine, the building block of chitin, inhibits growth of Neurospora crassa.

PubMed

Gaderer, Romana; Seidl-Seiboth, Verena; de Vries, Ronald P; Seiboth, Bernhard; Kappel, Lisa

2017-10-01

N-acetylglucosamine (GlcNAc) is the monomer of the polysaccharide chitin, an essential structural component of the fungal cell wall and the arthropod exoskeleton. We recently showed that the genes encoding the enzymes for GlcNAc catabolism are clustered in several ascomycetes. In the present study we tested these fungi for growth on GlcNAc and chitin. All fungi, containing the GlcNAc gene cluster, could grow on GlcNAc with the exception of four independent Neurospora crassa wild-type isolates, which were however able to grow on chitin. GlcNAc even inhibited their growth in the presence of other carbon sources. Genes involved in GlcNAc catabolism were strongly upregulated in the presence of GlcNAc, but during growth on chitin their expression was not increased. Deletion of hxk-3 (encoding the first catabolic enzyme, GlcNAc-hexokinase) and ngt-1 (encoding the GlcNAc transporter) improved growth of N. crassa on GlcNAc in the presence of glycerol. A crucial step in GlcNAc catabolism is enzymatic conversion from glucosamine-6-phosphate to fructose-6-phosphate, catalyzed by the glucosamine-6-phosphate deaminase, DAM-1. To assess, if DAM-1 is compromised in N. crassa, the orthologue from Trichoderma reesei, Trdam1, was expressed in N. crassa. Trdam1 expression partially alleviated the negative effects of GlcNAc in the presence of a second carbon source, but did not fully restore growth on GlcNAc. Our results indicate that the GlcNAc-catabolism pathway is bypassed during growth of N. crassa on chitin by use of an alternative pathway, emphasizing the different strategies that have evolved in the fungal kingdom for chitin utilization. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Chitosan but Not Chitin Activates the Inflammasome by a Mechanism Dependent upon Phagocytosis*

PubMed Central

Bueter, Chelsea L.; Lee, Chrono K.; Rathinam, Vijay A. K.; Healy, Gloria J.; Taron, Christopher H.; Specht, Charles A.; Levitz, Stuart M.

2011-01-01

Chitin is an abundant polysaccharide found in fungal cell walls, crustacean shells, and insect exoskeletons. The immunological properties of both chitin and its deacetylated derivative chitosan are of relevance because of frequent natural exposure and their use in medical applications. Depending on the preparation studied and the end point measured, these compounds have been reported to induce allergic responses, inflammatory responses, or no response at all. We prepared highly purified chitosan and chitin and examined the capacity of these glycans to stimulate murine macrophages to release the inflammasome-associated cytokine IL-1β. We found that although chitosan was a potent NLRP3 inflammasome activator, acetylation of the chitosan to chitin resulted in a near total loss of activity. The size of the chitosan particles played an important role, with small particles eliciting the greatest activity. An inverse relationship between size and stimulatory activity was demonstrated using chitosan passed through size exclusion filters as well as with chitosan-coated beads of defined size. Partial digestion of chitosan with pepsin resulted in a larger fraction of small phagocytosable particles and more potent inflammasome activity. Inhibition of phagocytosis with cytochalasin D abolished the IL-1β stimulatory activity of chitosan, offering an explanation for why the largest particles were nearly devoid of activity. Thus, the deacetylated polysaccharide chitosan potently activates the NLRP3 inflammasome in a phagocytosis-dependent manner. In contrast, chitin is relatively inert. PMID:21862582

Chitosan but not chitin activates the inflammasome by a mechanism dependent upon phagocytosis.

PubMed

Bueter, Chelsea L; Lee, Chrono K; Rathinam, Vijay A K; Healy, Gloria J; Taron, Christopher H; Specht, Charles A; Levitz, Stuart M

2011-10-14

Chitin is an abundant polysaccharide found in fungal cell walls, crustacean shells, and insect exoskeletons. The immunological properties of both chitin and its deacetylated derivative chitosan are of relevance because of frequent natural exposure and their use in medical applications. Depending on the preparation studied and the end point measured, these compounds have been reported to induce allergic responses, inflammatory responses, or no response at all. We prepared highly purified chitosan and chitin and examined the capacity of these glycans to stimulate murine macrophages to release the inflammasome-associated cytokine IL-1β. We found that although chitosan was a potent NLRP3 inflammasome activator, acetylation of the chitosan to chitin resulted in a near total loss of activity. The size of the chitosan particles played an important role, with small particles eliciting the greatest activity. An inverse relationship between size and stimulatory activity was demonstrated using chitosan passed through size exclusion filters as well as with chitosan-coated beads of defined size. Partial digestion of chitosan with pepsin resulted in a larger fraction of small phagocytosable particles and more potent inflammasome activity. Inhibition of phagocytosis with cytochalasin D abolished the IL-1β stimulatory activity of chitosan, offering an explanation for why the largest particles were nearly devoid of activity. Thus, the deacetylated polysaccharide chitosan potently activates the NLRP3 inflammasome in a phagocytosis-dependent manner. In contrast, chitin is relatively inert.

Effect of Moisture Content of Chitin-Calcium Silicate on Rate of Degradation of Cefotaxime Sodium.

PubMed

Al-Nimry, Suhair S; Alkhamis, Khouloud A

2018-04-01

Assessment of incompatibilities between active pharmaceutical ingredient and pharmaceutical excipients is an important part of preformulation studies. The objective of the work was to assess the effect of moisture content of chitin calcium silicate of two size ranges (two specific surface areas) on the rate of degradation of cefotaxime sodium. The surface area of the excipient was determined using adsorption method. The effect of moisture content of a given size range on the stability of the drug was determined at 40°C in the solid state. The moisture content was determined at the beginning and the end of the kinetic study using TGA. The degradation in solution was studied for comparison. Increasing the moisture content of the excipient of size range 63-180 μm (surface area 7.2 m 2 /g) from 3.88 to 8.06% increased the rate of degradation of the drug more than two times (from 0.0317 to 0.0718 h -1 ). While an opposite trend was observed for the excipient of size range < 63 μm (surface area 55.4 m 2 /g). The rate of degradation at moisture content < 3% was 0.4547 h -1 , almost two times higher than that (0.2594 h -1 ) at moisture content of 8.54%, and the degradation in solid state at both moisture contents was higher than that in solution (0.0871 h -1 ). In conclusion, the rate of degradation in solid should be studied taking into consideration the specific surface area and moisture content of the excipient at the storage condition and it may be higher than that in solution.

Extraction and physicochemical characterization of chitin and chitosan from Zophobas morio larvae in varying sodium hydroxide concentration.

PubMed

Soon, Chu Yong; Tee, Yee Bond; Tan, Choon Hui; Rosnita, Abdul Talib; Khalina, Abdan

2018-03-01

Large amount of sodium hydroxide (NaOH) is consumed to remove the protein content in chitin biomass during deproteinization. However, excessive NaOH concentration used might lead to the reduction of cost effectiveness during chitin extraction. Hence, the present study aimed to extract and evaluate the physicochemical properties of chitin and chitosan isolated from superworm (Zophobas morio) larvae using 0.5M-2.0M of NaOH. The extracted chitin and chitosan were subjected to Fourier Transform Infrared Spectroscopy (FT-IR), elemental analysis, Scanning Electron Microscope (SEM), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and X-ray Diffraction (XRD). The 0.5M NaOH treatment resulted in the highest yield of chitin (5.43%), but produced the lowest yield (65.84%) of chitosan. The extracted chitin samples had relatively high degree of acetylation (DA) (82.39%-101.39%). Both chitin and chitosan showed smooth surface with tiny pores. The extracted chitin samples were confirmed as α-chitin based on the FT-IR and TGA. The chitin samples were amorphous with low degree of crystallinity. From TGA, the Chitosan 3 extracted was partially deacetylated. Both DPPH radical scavenging and ferric-chelating assay showed positive correlation with DD of chitosan isolates. However, the chitosan isolates were not fully dissolved, resulting in lower radical scavenging and ferric-chelating ability compared to commercial chitosan. Copyright © 2017. Published by Elsevier B.V.

The chitin-binding domain of a GH-18 chitinase from Vibrio harveyi is crucial for chitin-chitinase interactions.

PubMed

Suginta, Wipa; Sirimontree, Paknisa; Sritho, Natchanok; Ohnuma, Takayuki; Fukamizo, Tamo

2016-12-01

Vibrio harveyi chitinase A (VhChiA) is a GH-18 glycosyl hydrolase with a structure containing three distinct domains: i) the N-terminal chitin-binding domain; ii) the (α/β) 8 TIM barrel catalytic domain; and iii) the α+β insertion domain. In this study, we cloned the gene fragment encoding the chitin-binding domain of VhChiA, termed ChBD Vh ChiA . The recombinant ChBD Vh ChiA was heterologously expressed in E. coli BL21 strain Tuner(DE3)pLacI host cells, and purified to homogeneity. CD measurements suggested that ChBD Vh ChiA contained β-sheets as major structural components and fluorescence spectroscopy showed that the protein domain was folded correctly, and suitable for functional characterization. Chitin binding assays showed that ChBD Vh ChiA bound to both α- and β-chitins, with the greatest affinity for β-colloidal chitin, but barely bound to polymeric chitosan. These results identified the tandem N-acetamido functionality on chitin chains as the specific sites of enzyme-substrate interactions. The binding affinity of the isolated domain was significantly lower than that of intact VhChiA, suggesting that the catalytic domain works synergistically with the chitin-binding domain to guide the polymeric substrate into the substrate binding cleft. These data confirm the physiological role of the chitin-binding domain of the marine bacterial GH-18 chitinase A in chitin-chitinase interactions. Copyright © 2016 Elsevier B.V. All rights reserved.

Chitin synthetase in encysting Giardia lamblia and Entamoeba invadens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, S.; Gillin, F.D.

1987-05-01

Giardia lamblia (Gl) and Entamoeba invadens (Ei) are protozoan parasites with two morphologic stages in their life cycles. Motile trophozoites colonize the intestine of humans and reptiles respectively. Water resistant cysts, which can survive outside the host, transmit infection. In vitro cyst formation of Ei from trophozoites has been reported, and the authors have recently induced in vitro encystation of Gl. Although the cyst walls of both parasites contain chitin, it synthesis by encysting trophozoites has not been reported. The authors now show that encystation conditions greatly increase chitin synthetase (CS) specific activity (incorporation of /sup 3/H GlcNAc from UDP-GlcNAcmore » into TCA-or alcohol-precipitable material). Extracts of encysting Gl incorporated 3.6 nmol/mg protein in 5 hr compared to < 0.005 in controls. Extracts of encysting Fi incorporated 4.8 n mol/mg protein, compared to 1.7 in the control. CS activity of both parasites requires preformed chitin. The Gl enzyme requires a reducing agent, is inhibited by digitonin and the CS inhibitors, polyoxin D and Nikkomycin, but not by tunicamycin. The product is digested by chitinase. Ei enzyme does not require a reducing agent and is stimulated by 1 mg/ml digitonin, but inhibited by higher concentrations. These studies demonstrate CS enzymes which may play important roles in encystation of Gl and Ei.« less

The Tribolium chitin synthase genes TcCHS1 and TcCHS2 are specialized for synthesis of epidermal cuticle and midgut peritrophic matrix.

PubMed

Arakane, Y; Muthukrishnan, S; Kramer, K J; Specht, C A; Tomoyasu, Y; Lorenzen, M D; Kanost, M; Beeman, R W

2005-10-01

Functional analysis of the two chitin synthase genes, TcCHS1 and TcCHS2, in the red flour beetle, Tribolium castaneum, revealed unique and complementary roles for each gene. TcCHS1-specific RNA interference (RNAi) disrupted all three types of moult (larval-larval, larval-pupal and pupal-adult) and greatly reduced whole-body chitin content. Exon-specific RNAi showed that splice variant 8a of TcCHS1 was required for both the larval-pupal and pupal-adult moults, whereas splice variant 8b was required only for the latter. TcCHS2-specific RNAi had no effect on metamorphosis or on total body chitin content. However, RNAi-mediated down-regulation of TcCHS2, but not TcCHS1, led to cessation of feeding, a dramatic shrinkage in larval size and reduced chitin content in the midgut.

Chitin-natural clay nanotubes hybrid hydrogel.

PubMed

Liu, Mingxian; Zhang, Yun; Li, Jingjing; Zhou, Changren

2013-07-01

Novel hybrid hydrogel was synthesized from chitin NaOH/urea aqueous solution in presence of halloysite nanotubes (HNTs) via crosslinking with epichlorohydrin. Fourier transform infrared (FT-IR) spectra and atomic force microscopy (AFM) results confirmed the interfacial interactions in the chitin-HNTs hybrid hydrogel. The compressive strength and shear modulus of chitin hydrogel were significantly increased by HNTs as shown in the static compressive experiment and rheology measurement. The hybrid hydrogels showed highly porous microstructures by scanning electron microscopy (SEM). The swelling ratio of chitin hydrogel decreased because of the addition of HNTs. The malachite green's absorption experiment result showed that the hybrid hydrogel exhibited much higher absorption rate than the pure chitin hydrogel. The prepared hybrid hydrogel had potential applications in waste treatment and biomedical areas. Copyright © 2013 Elsevier B.V. All rights reserved.

Strategies To Discover the Structural Components of Cyst and Oocyst Walls

PubMed Central

Bushkin, G. Guy; Chatterjee, Aparajita; Robbins, Phillips W.

2013-01-01

Cysts of Giardia lamblia and Entamoeba histolytica and oocysts of Toxoplasma gondii and Cryptosporidium parvum are the infectious and sometimes diagnostic forms of these parasites. To discover the structural components of cyst and oocyst walls, we have developed strategies based upon a few simple assumptions. Briefly, the most abundant wall proteins are identified by monoclonal antibodies or mass spectrometry. Structural components include a sugar polysaccharide (chitin for Entamoeba, β-1,3-linked glucose for Toxoplasma, and β-1,3-linked GalNAc for Giardia) and/or acid-fast lipids (Toxoplasma and Cryptosporidium). Because Entamoeba cysts and Toxoplasma oocysts are difficult to obtain, studies of walls of nonhuman pathogens (E. invadens and Eimeria, respectively) accelerate discovery. Biochemical methods to dissect fungal walls work well for cyst and oocyst walls, although the results are often unexpected. For example, echinocandins, which inhibit glucan synthases and kill fungi, arrest the development of oocyst walls and block their release into the intestinal lumen. Candida walls are coated with mannans, while Entamoeba cysts are coated in a dextran-like glucose polymer. Models for cyst and oocyst walls derive from their structural components and organization within the wall. Cyst walls are composed of chitin fibrils and lectins that bind chitin (Entamoeba) or fibrils of the β-1,3-GalNAc polymer and lectins that bind the polymer (Giardia). Oocyst walls of Toxoplasma have two distinct layers that resemble those of fungi (β-1,3-glucan in the inner layer) or mycobacteria (acid-fast lipids in the outer layer). Oocyst walls of Cryptosporidium have a rigid bilayer of acid-fast lipids and inner layer of oocyst wall proteins. PMID:24096907

Three-dimensional chitin rings from body segments of a pet diplopod species: Characterization and protein interaction studies.

PubMed

Kaya, Murat; Mulerčikas, Povilas; Sargin, Idris; Kazlauskaitė, Sonata; Baublys, Vykintas; Akyuz, Bahar; Bulut, Esra; Tubelytė, Vaida

2016-11-01

Physicochemical characterization of new chitin isolates can provide valuable insights into designing of biomimetic materials. Chitin isolates with a definite three-dimensional (3D) structure can exhibit characteristics that distinguish them from other chitin specimens that are in form of powder or flakes without a definite and uniform shape. Herein, 3D chitin rings were produced from body segments of a diplopod (Archispirostreptus gigas) inhabiting tropical regions. This organism is cultured easily and can reach 38cm in length, which makes it a suitable source for isolation of chitin. The chitin rings were characterized via TGA, FT-IR, SEM and XRD analyses. Enzymatic digestion test with chitinase demonstrated that chitin isolates had high purity (digestion rate: 97.4%). The source organism had high chitin content; 21.02±2.23% on dry weight. Interactions of the chitin rings with bovine serum albumin (BSA) protein were studied under different conditions (pH: 4.0-8.0, chitin amount: 6-14mg, contact time: 30-360min, protein concentration: 0.2-1mg/mL). The highest BSA adsorption was observed at pH5.0 at 20°C. The adsorption equilibrium data exhibited a better fit to Langmuir adsorption and the pseudo-first order kinetic models. The findings presented here can be useful for further studies aiming to develop biocompatible and nontoxic biomaterials. Copyright © 2016 Elsevier B.V. All rights reserved.

Cooperative Degradation of Chitin by Extracellular and Cell Surface-Expressed Chitinases from Paenibacillus sp. Strain FPU-7

PubMed Central

Itoh, Takafumi; Hibi, Takao; Fujii, Yutaka; Sugimoto, Ikumi; Fujiwara, Akihiro; Suzuki, Fumiko; Iwasaki, Yukimoto; Kim, Jin-Kyung; Taketo, Akira

2013-01-01

Chitin, a major component of fungal cell walls and invertebrate cuticles, is an exceedingly abundant polysaccharide, ranking next to cellulose. Industrial demand for chitin and its degradation products as raw materials for fine chemical products is increasing. A bacterium with high chitin-decomposing activity, Paenibacillus sp. strain FPU-7, was isolated from soil by using a screening medium containing α-chitin powder. Although FPU-7 secreted several extracellular chitinases and thoroughly digested the powder, the extracellular fluid alone broke them down incompletely. Based on expression cloning and phylogenetic analysis, at least seven family 18 chitinase genes were found in the FPU-7 genome. Interestingly, the product of only one gene (chiW) was identified as possessing three S-layer homology (SLH) domains and two glycosyl hydrolase family 18 catalytic domains. Since SLH domains are known to function as anchors to the Gram-positive bacterial cell surface, ChiW was suggested to be a novel multimodular surface-expressed enzyme and to play an important role in the complete degradation of chitin. Indeed, the ChiW protein was localized on the cell surface. Each of the seven chitinase genes (chiA to chiF and chiW) was cloned and expressed in Escherichia coli cells for biochemical characterization of their products. In particular, ChiE and ChiW showed high activity for insoluble chitin. The high chitinolytic activity of strain FPU-7 and the chitinases may be useful for environmentally friendly processing of chitin in the manufacture of food and/or medicine. PMID:24077704

Presence of a Large β(1-3)Glucan Linked to Chitin at the Saccharomyces cerevisiae Mother-Bud Neck Suggests Involvement in Localized Growth Control

PubMed Central

Blanco, Noelia; Arroyo, Javier

2012-01-01

Previous results suggested that the chitin ring present at the yeast mother-bud neck, which is linked specifically to the nonreducing ends of β(1-3)glucan, may help to suppress cell wall growth at the neck by competing with β(1-6)glucan and thereby with mannoproteins for their attachment to the same sites. Here we explored whether the linkage of chitin to β(1-3)glucan may also prevent the remodeling of this polysaccharide that would be necessary for cell wall growth. By a novel mild procedure, β(1-3)glucan was isolated from cell walls, solubilized by carboxymethylation, and fractionated by size exclusion chromatography, giving rise to a very high-molecular-weight peak and to highly polydisperse material. The latter material, soluble in alkali, may correspond to glucan being remodeled, whereas the large-size fraction would be the final cross-linked structural product. In fact, the β(1-3)glucan of buds, where growth occurs, is solubilized by alkali. A gas1 mutant with an expected defect in glucan elongation showed a large increase in the polydisperse fraction. By a procedure involving sodium hydroxide treatment, carboxymethylation, fractionation by affinity chromatography on wheat germ agglutinin-agarose, and fractionation by size chromatography on Sephacryl columns, it was shown that the β(1-3)glucan attached to chitin consists mostly of high-molecular-weight material. Therefore, it appears that linkage to chitin results in a polysaccharide that cannot be further remodeled and does not contribute to growth at the neck. In the course of these experiments, the new finding was made that part of the chitin forms a noncovalent complex with β(1-3)glucan. PMID:22366124

Presence of a large β(1-3)glucan linked to chitin at the Saccharomyces cerevisiae mother-bud neck suggests involvement in localized growth control.

PubMed

Cabib, Enrico; Blanco, Noelia; Arroyo, Javier

2012-04-01

Previous results suggested that the chitin ring present at the yeast mother-bud neck, which is linked specifically to the nonreducing ends of β(1-3)glucan, may help to suppress cell wall growth at the neck by competing with β(1-6)glucan and thereby with mannoproteins for their attachment to the same sites. Here we explored whether the linkage of chitin to β(1-3)glucan may also prevent the remodeling of this polysaccharide that would be necessary for cell wall growth. By a novel mild procedure, β(1-3)glucan was isolated from cell walls, solubilized by carboxymethylation, and fractionated by size exclusion chromatography, giving rise to a very high-molecular-weight peak and to highly polydisperse material. The latter material, soluble in alkali, may correspond to glucan being remodeled, whereas the large-size fraction would be the final cross-linked structural product. In fact, the β(1-3)glucan of buds, where growth occurs, is solubilized by alkali. A gas1 mutant with an expected defect in glucan elongation showed a large increase in the polydisperse fraction. By a procedure involving sodium hydroxide treatment, carboxymethylation, fractionation by affinity chromatography on wheat germ agglutinin-agarose, and fractionation by size chromatography on Sephacryl columns, it was shown that the β(1-3)glucan attached to chitin consists mostly of high-molecular-weight material. Therefore, it appears that linkage to chitin results in a polysaccharide that cannot be further remodeled and does not contribute to growth at the neck. In the course of these experiments, the new finding was made that part of the chitin forms a noncovalent complex with β(1-3)glucan.

Helicoidal Organization of Chitin in the Cuticle of the Migratory Locust Requires the Function of the Chitin Deacetylase2 Enzyme (LmCDA2)*

PubMed Central

Yu, Rongrong; Liu, Weimin; Li, Daqi; Zhao, Xiaoming; Ding, Guowei; Zhang, Min; Ma, Enbo; Zhu, KunYan; Li, Sheng; Moussian, Bernard; Zhang, Jianzhen

2016-01-01

In the three-dimensional extracellular matrix of the insect cuticle, horizontally aligned microfibrils composed of the polysaccharide chitin and associated proteins are stacked either parallel to each other or helicoidally. The underlying molecular mechanisms that implement differential chitin organization are largely unknown. To learn more about cuticle organization, we sought to study the role of chitin deacetylases (CDA) in this process. In the body cuticle of nymphs of the migratory locust Locusta migratoria, helicoidal chitin organization is changed to an organization with unidirectional microfibril orientation when LmCDA2 expression is knocked down by RNA interference. In addition, the LmCDA2-deficient cuticle is less compact suggesting that LmCDA2 is needed for chitin packaging. Animals with reduced LmCDA2 activity die at molting, underlining that correct chitin organization is essential for survival. Interestingly, we find that LmCDA2 localizes only to the initially produced chitin microfibrils that constitute the apical site of the chitin stack. Based on our data, we hypothesize that LmCDA2-mediated chitin deacetylation at the beginning of chitin production is a decisive reaction that triggers helicoidal arrangement of subsequently assembled chitin-protein microfibrils. PMID:27637332

Synthesis and characterization of polypyrrole grafted chitin

NASA Astrophysics Data System (ADS)

Ramaprasad, A. T.; Latha, D.; Rao, Vijayalakshmi

2017-05-01

Synthesis and characterization of chitin grafted with polypyrrole (PPy) is reported in this paper. Chitin is soaked in pyrrole solution of various concentrations for different time intervals and polymerized using ammonium peroxy disulphate (APS) as an initiator. Grafting percentage of polypyrrole onto chitin is calculated from weight of chitin before and after grafting. Grafting of polymer is further verified by dissolution studies. The grafted polymer samples are characterized by FTIR, UV-Vis absorption spectrum, XRD, DSC, TGA, AFM, SEM and conductivity studies.

Biodegradation of the chitin-protein complex in crustacean cuticle

USGS Publications Warehouse

Artur, Stankiewicz B.; Mastalerz, Maria; Hof, C.H.J.; Bierstedt, A.; Flannery, M.B.; Briggs, D.E.G.; Evershed, R.P.

1998-01-01

Arthropod cuticles consist predominantly of chitin cross-linked with proteins. While there is some experimental evidence that this chitin-protein complex may resist decay, the chemical changes that occur during degradation have not been investigated in detail. The stomatopod crustacean Neogonodactylus oerstedii was decayed in the laboratory under anoxic conditions. A combination of pyrolysis-gas chromatography/mass spectrometry and FTIR revealed extensive chemical changes after just 2 weeks that resulted in a cuticle composition dominated by chitin. Quantitative analysis of amino acids (by HPLC) and chitin showed that the major loss of proteins and chitin occurred between weeks 1 and 2. After 8 weeks tyrosine, tryptophan and valine are the most prominent amino acid moieties, showing their resistance to degradation. The presence of cyclic ketones in the pyrolysates indicates that mucopolysaccharides or other bound non-chitinous carbohydrates are also resistant to decay. There is no evidence of structural degradation of chitin prior to 8 weeks when FTIR revealed a reduction in chitin-specific bands. The chemical changes are paralleled by structural changes in the cuticle, which becomes an increasingly open structure consisting of loose chitinous fibres. The rapid rate of decay in the experiments suggests that where chitin and protein are preserved in fossil cuticles degradation must have been inhibited.Arthropod cuticles consist predominantly of chitin cross-linked with proteins. While there is some experimental evidence that this chitin-protein complex may resist decay, the chemical changes that occur during degradation have not been investigated in detail. The stomatopod crustacean Neogonodactylus oerstedii was decayed in the laboratory under anoxic conditions. A combination of pyrolysis-gas chromatography/mass spectrometry and FTIR revealed extensive chemical changes after just 2 weeks that resulted in a cuticle composition dominated by chitin. Quantitative

Preparation and characterization of high purity β-chitin from squid pens (Loligo chenisis).

PubMed

Cuong, Hoang Ngoc; Minh, Nguyen Cong; Van Hoa, Nguyen; Trung, Trang Si

2016-12-01

Squid pens were extracted by a NaOH solution at 80°C for 10h to remove protein and minerals. The as-prepared β-chitin had a high molecular weight (8.5±0.1×10 3 kDa), a low protein content (0.63±0.02wt.%), and a negligible amount of minerals. This method avoids the conventional method for the removal of minerals from shrimp and crab shells by HCl. The purity of resulting products was measured by NMR and FTIR. Moreover, the morphology and crystallinity of β-chitin was characterized by SEM and XRD. The β-chitin with long chains and high purity is suitable for producing high quantity β-chitosan for various potential applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultrasonication and steam-explosion as chitin pretreatments for chitin oligosaccharide production by chitinases of Lecanicillium lecanii.

PubMed

Villa-Lerma, Guadalupe; González-Márquez, Humberto; Gimeno, Miquel; López-Luna, Alberto; Bárzana, Eduardo; Shirai, Keiko

2013-10-01

In this study, chitin oligosaccharides have been successfully produced using chitinases from submerged fermentation of Lecanicillium lecanii. The highest Hex, Chit and Prot production was 0.14, 0.26 and 2.05 U/mg of protein, respectively, which were attained varying pH from 5 to 8 after 96 h. Culture conditions conducted at constant pH of 6 resulted in significantly lower enzyme production. The crude enzyme was partially purified by salting out with (NH4)2SO4 followed by size exclusion chromatography to isolate the chitinase mixture for further chitin hydrolysis assays. In this regard, chitin substrates were pretreated with sonication and steam explosion prior to enzymatic reaction. Structural changes were observed with steam explosion with 11.28% reduction of the crystallinity index attained with the lowest chitin/water ratio (0.1g/mL). Pretreated chitins reached the highest production of reducing sugars (0.37 mg/mL) and GlcNAc (0.59 mg/mL) in 23.6% yield. Copyright © 2013 Elsevier Ltd. All rights reserved.

Helicoidal Organization of Chitin in the Cuticle of the Migratory Locust Requires the Function of the Chitin Deacetylase2 Enzyme (LmCDA2).

PubMed

Yu, Rongrong; Liu, Weimin; Li, Daqi; Zhao, Xiaoming; Ding, Guowei; Zhang, Min; Ma, Enbo; Zhu, KunYan; Li, Sheng; Moussian, Bernard; Zhang, Jianzhen

2016-11-18

In the three-dimensional extracellular matrix of the insect cuticle, horizontally aligned microfibrils composed of the polysaccharide chitin and associated proteins are stacked either parallel to each other or helicoidally. The underlying molecular mechanisms that implement differential chitin organization are largely unknown. To learn more about cuticle organization, we sought to study the role of chitin deacetylases (CDA) in this process. In the body cuticle of nymphs of the migratory locust Locusta migratoria, helicoidal chitin organization is changed to an organization with unidirectional microfibril orientation when LmCDA2 expression is knocked down by RNA interference. In addition, the LmCDA2-deficient cuticle is less compact suggesting that LmCDA2 is needed for chitin packaging. Animals with reduced LmCDA2 activity die at molting, underlining that correct chitin organization is essential for survival. Interestingly, we find that LmCDA2 localizes only to the initially produced chitin microfibrils that constitute the apical site of the chitin stack. Based on our data, we hypothesize that LmCDA2-mediated chitin deacetylation at the beginning of chitin production is a decisive reaction that triggers helicoidal arrangement of subsequently assembled chitin-protein microfibrils. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Chitovibrin: a chitin-binding lectin from Vibrio parahemolyticus.

PubMed

Gildemeister, O S; Zhu, B C; Laine, R A

1994-12-01

A novel 134 kDa, calcium-independent chitin-binding lectin, 'chitovibrin', is secreted by the marine bacterium Vibrio parahemolyticus, inducible with chitin or chitin-oligomers. Chitovibrin shows no apparent enzymatic activity but exhibits a strong affinity for chitin and chito-oligomers > dp9. The protein has an isoelectric pH of 3.6, shows thermal tolerance, binds chitin with an optimum at pH 6 and is active in 0-4 M NaCl. Chitovibrin appears to be completely different from other reported Vibrio lectins and may function to bind V. parahemolyticus to chitin substrates, or to capture or sequester chito-oligomers. It may be a member of a large group of recently described proteins in Vibrios related to a complex chitinoclastic (chitinivorous) system.

LYK4, a Lysin Motif Receptor-Like Kinase, Is Important for Chitin Signaling and Plant Innate Immunity in Arabidopsis1[C][W][OA

PubMed Central

Wan, Jinrong; Tanaka, Kiwamu; Zhang, Xue-Cheng; Son, Geon Hui; Brechenmacher, Laurent; Nguyen, Tran Hong Nha; Stacey, Gary

2012-01-01

Chitin is commonly found in fungal cell walls and is one of the well-studied microbe/pathogen-associated molecular patterns. Previous studies showed that lysin motif (LysM)-containing proteins are essential for plant recognition of chitin, leading to the activation of plant innate immunity. In Arabidopsis (Arabidopsis thaliana), the LYK1/CERK1 (for LysM-containing receptor-like kinase1/chitin elicitor receptor kinase1) was shown to be essential for chitin recognition, whereas in rice (Oryza sativa), the LysM-containing protein, CEBiP (for chitin elicitor-binding protein), was shown to be involved in chitin recognition. Unlike LYK1/CERK1, CEBiP lacks an intracellular kinase domain. Arabidopsis possesses three CEBiP-like genes. Our data show that mutations in these genes, either singly or in combination, did not compromise the response to chitin treatment. Arabidopsis also contains five LYK genes. Analysis of mutations in LYK2, -3, -4, or -5 showed that LYK4 is also involved in chitin signaling. The lyk4 mutants showed reduced induction of chitin-responsive genes and diminished chitin-induced cytosolic calcium elevation as well as enhanced susceptibility to both the bacterial pathogen Pseudomonas syringae pv tomato DC3000 and the fungal pathogen Alternaria brassicicola, although these phenotypes were not as dramatic as that seen in the lyk1/cerk1 mutants. Similar to LYK1/CERK1, the LYK4 protein was also localized to the plasma membrane. Therefore, LYK4 may play a role in the chitin recognition receptor complex to assist chitin signal transduction and plant innate immunity. PMID:22744984

Chitin and Its Effects on Inflammatory and Immune Responses.

PubMed

Elieh Ali Komi, Daniel; Sharma, Lokesh; Dela Cruz, Charles S

2018-04-01

Chitin, a potential allergy-promoting pathogen-associated molecular pattern (PAMP), is a linear polymer composed of N-acetylglucosamine residues which are linked by β-(1,4)-glycosidic bonds. Mammalians are potential hosts for chitin-containing protozoa, fungi, arthropods, and nematodes; however, mammalians themselves do not synthetize chitin and thus it is considered as a potential target for recognition by mammalian immune system. Chitin is sensed primarily in the lungs or gut where it activates a variety of innate (eosinophils, macrophages) and adaptive immune cells (IL-4/IL-13 expressing T helper type-2 lymphocytes). Chitin induces cytokine production, leukocyte recruitment, and alternative macrophage activation. Intranasal or intraperitoneal administration of chitin (varying in size, degree of acetylation and purity) to mice has been applied as a routine approach to investigate chitin's priming effects on innate and adaptive immunity. Structural chitin present in microorganisms is actively degraded by host true chitinases, including acidic mammalian chitinases and chitotriosidase into smaller fragments that can be sensed by mammalian receptors such as FIBCD1, NKR-P1, and RegIIIc. Immune recognition of chitin also involves pattern recognition receptors, mainly via TLR-2 and Dectin-1, to activate immune cells to induce cytokine production and creation of an immune network that results in inflammatory and allergic responses. In this review, we will focus on various immunological aspects of the interaction between chitin and host immune system such as sensing, interactions with immune cells, chitinases as chitin degrading enzymes, and immunologic applications of chitin.

Chemical Organization of the Cell Wall Polysaccharide Core of Malassezia restricta

PubMed Central

Stalhberger, Thomas; Simenel, Catherine; Clavaud, Cécile; Eijsink, Vincent G. H.; Jourdain, Roland; Delepierre, Muriel; Latgé, Jean-Paul; Breton, Lionel; Fontaine, Thierry

2014-01-01

Malassezia species are ubiquitous residents of human skin and are associated with several diseases such as seborrheic dermatitis, tinea versicolor, folliculitis, atopic dermatitis, and scalp conditions such as dandruff. Host-Malassezia interactions and mechanisms to evade local immune responses remain largely unknown. Malassezia restricta is one of the most predominant yeasts of the healthy human skin, its cell wall has been investigated in this paper. Polysaccharides in the M. restricta cell wall are almost exclusively alkali-insoluble, showing that they play an essential role in the organization and rigidity of the M. restricta cell wall. Fractionation of cell wall polymers and carbohydrate analyses showed that the polysaccharide core of the cell wall of M. restricta contained an average of 5% chitin, 20% chitosan, 5% β-(1,3)-glucan, and 70% β-(1,6)-glucan. In contrast to other yeasts, chitin and chitosan are relatively abundant, and β-(1,3)-glucans constitute a minor cell wall component. The most abundant polymer is β-(1,6)-glucans, which are large molecules composed of a linear β-(1,6)-glucan chains with β-(1,3)-glucosyl side chain with an average of 1 branch point every 3.8 glucose unit. Both β-glucans are cross-linked, forming a huge alkali-insoluble complex with chitin and chitosan polymers. Data presented here show that M. restricta has a polysaccharide organization very different of all fungal species analyzed to date. PMID:24627479

Chemical organization of the cell wall polysaccharide core of Malassezia restricta.

PubMed

Stalhberger, Thomas; Simenel, Catherine; Clavaud, Cécile; Eijsink, Vincent G H; Jourdain, Roland; Delepierre, Muriel; Latgé, Jean-Paul; Breton, Lionel; Fontaine, Thierry

2014-05-02

Malassezia species are ubiquitous residents of human skin and are associated with several diseases such as seborrheic dermatitis, tinea versicolor, folliculitis, atopic dermatitis, and scalp conditions such as dandruff. Host-Malassezia interactions and mechanisms to evade local immune responses remain largely unknown. Malassezia restricta is one of the most predominant yeasts of the healthy human skin, its cell wall has been investigated in this paper. Polysaccharides in the M. restricta cell wall are almost exclusively alkali-insoluble, showing that they play an essential role in the organization and rigidity of the M. restricta cell wall. Fractionation of cell wall polymers and carbohydrate analyses showed that the polysaccharide core of the cell wall of M. restricta contained an average of 5% chitin, 20% chitosan, 5% β-(1,3)-glucan, and 70% β-(1,6)-glucan. In contrast to other yeasts, chitin and chitosan are relatively abundant, and β-(1,3)-glucans constitute a minor cell wall component. The most abundant polymer is β-(1,6)-glucans, which are large molecules composed of a linear β-(1,6)-glucan chains with β-(1,3)-glucosyl side chain with an average of 1 branch point every 3.8 glucose unit. Both β-glucans are cross-linked, forming a huge alkali-insoluble complex with chitin and chitosan polymers. Data presented here show that M. restricta has a polysaccharide organization very different of all fungal species analyzed to date.

A chitin deacetylase of Podospora anserina has two functional chitin binding domains and a unique mode of action.

PubMed

Hoßbach, Janina; Bußwinkel, Franziska; Kranz, Andreas; Wattjes, Jasper; Cord-Landwehr, Stefan; Moerschbacher, Bruno M

2018-03-01

Chitosan is a structurally diverse biopolymer that is commercially derived from chitin by chemical processing, but chitin deacetylases (CDAs) potentially offer a sustainable and more controllable approach allowing the production of chitosans with tailored structures and biological activities. We investigated the CDA from Podospora anserina (PaCDA) which is closely related to Colletotrichum lindemuthianum CDA in the catalytic domain, but unique in having two chitin-binding domains. We produced recombinant PaCDA in Hansenula polymorpha for biochemical characterization and found that the catalytic domain of PaCDA is also functionally similar to C. lindemuthianum CDA, though differing in detail. When studying the enzyme's mode of action on chitin oligomers by quantitative mass-spectrometric sequencing, we found almost all possible sequences up to full deacetylation but with a clear preference for specific products. Deletion muteins lacking one or both CBDs confirmed their proposed function in supporting the enzymatic conversion of the insoluble substrate colloidal chitin. Copyright © 2017. Published by Elsevier Ltd.

Deletion of a Chitin Synthase Gene in a Citric Acid Producing Strain of Aspergillus niger

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rinker, Torri E.; Baker, Scott E.

Citric acid production by the filamentous fungus Aspergillus niger is carried out in a process that causes the organism to drastically alter its morphology. This altered morphology includes hyphal swelling and highly limited polar growth resulting in clumps of swollen cells that eventually aggregate into pellets of approximately 100 microns in diameter. In this pelleted form, A. niger has increased citric acid production as compared to growth in filamentous form. Chitin is a crucial component of the cell wall of filamentous fungi. Alterations in the deposition or production of chitin may have profound effects on the morphology of the organism.more » In order to study the role of chitin synthesis in pellet formation we have deleted a chitin synthase gene (csmA) in Aspergillus niger strain ATCC 11414 using a PCR based deletion construct. This class of chitin synthases is only found in filamentous fungi and is not present in yeasts. The csmA genes contain a myosin motor domain at the N-terminus and a chitin synthesis domain at the C-terminus. They are believed to contribute to the specialized polar growth observed in filamentous fungi that is lacking in yeasts. The csmA deletion strain (csmAΔ) was subjected to minimal media with and without osmotic stabilizers as well as tested in citric acid production media. Without osmotic stabilizers, the mutant germlings were abnormally swollen, primarily in the subapical regions, and contained large vacuoles. However, this swelling is ultimately not inhibitory to growth as the germlings are able to recover and undergo polar growth. Colony formation was largely unaffected in the absence of osmotic stabilizers. In citric acid production media csmAΔ was observed to have a 2.5 fold increase in citric acid production. The controlled expression of this class of chitin synthases may be useful for improving production of organic acids in filamentous fungi.« less

LYM2-dependent chitin perception limits molecular flux via plasmodesmata

PubMed Central

Faulkner, Christine; Petutschnig, Elena; Benitez-Alfonso, Yoselin; Beck, Martina; Robatzek, Silke; Lipka, Volker; Maule, Andrew J.

2013-01-01

Chitin acts as a pathogen-associated molecular pattern from fungal pathogens whose perception triggers a range of defense responses. We show that LYSIN MOTIF DOMAIN-CONTAINING GLYCOSYLPHOSPHATIDYLINOSITOL-ANCHORED PROTEIN 2 (LYM2), the Arabidopsis homolog of a rice chitin receptor-like protein, mediates a reduction in molecular flux via plasmodesmata in the presence of chitin. For this response, lym2-1 mutants are insensitive to the presence of chitin, but not to the flagellin derivative flg22. Surprisingly, the chitin-recognition receptor CHITIN ELCITOR RECEPTOR KINASE 1 (CERK1) is not required for chitin-induced changes to plasmodesmata flux, suggesting that there are at least two chitin-activated response pathways in Arabidopsis and that LYM2 is not required for CERK1-mediated chitin-triggered defense responses, indicating that these pathways are independent. In accordance with a role in the regulation of intercellular flux, LYM2 is resident at the plasma membrane and is enriched at plasmodesmata. Chitin-triggered regulation of molecular flux between cells is required for defense responses against the fungal pathogen Botrytis cinerea, and thus we conclude that the regulation of symplastic continuity and molecular flux between cells is a vital component of chitin-triggered immunity in Arabidopsis. PMID:23674687

First report on chitinous holdfast in sponges (Porifera).

PubMed

Ehrlich, Hermann; Kaluzhnaya, Oksana V; Tsurkan, Mikhail V; Ereskovsky, Alexander; Tabachnick, Konstantin R; Ilan, Micha; Stelling, Allison; Galli, Roberta; Petrova, Olga V; Nekipelov, Serguei V; Sivkov, Victor N; Vyalikh, Denis; Born, René; Behm, Thomas; Ehrlich, Andre; Chernogor, Lubov I; Belikov, Sergei; Janussen, Dorte; Bazhenov, Vasilii V; Wörheide, Gert

2013-07-07

A holdfast is a root- or basal plate-like structure of principal importance that anchors aquatic sessile organisms, including sponges, to hard substrates. There is to date little information about the nature and origin of sponges' holdfasts in both marine and freshwater environments. This work, to our knowledge, demonstrates for the first time that chitin is an important structural component within holdfasts of the endemic freshwater demosponge Lubomirskia baicalensis. Using a variety of techniques (near-edge X-ray absorption fine structure, Raman, electrospray ionization mas spectrometry, Morgan-Elson assay and Calcofluor White staining), we show that chitin from the sponge holdfast is much closer to α-chitin than to β-chitin. Most of the three-dimensional fibrous skeleton of this sponge consists of spicule-containing proteinaceous spongin. Intriguingly, the chitinous holdfast is not spongin-based, and is ontogenetically the oldest part of the sponge body. Sequencing revealed the presence of four previously undescribed genes encoding chitin synthases in the L. baicalensis sponge. This discovery of chitin within freshwater sponge holdfasts highlights the novel and specific functions of this biopolymer within these ancient sessile invertebrates.

Suppressing the activity of trehalase with validamycin disrupts the trehalose and chitin biosynthesis pathways in the rice brown planthopper, Nilaparvata lugens.

PubMed

Tang, Bin; Yang, Mengmeng; Shen, Qida; Xu, Yanxia; Wang, Huijuan; Wang, Shigui

2017-04-01

Trehalase (TRE) is a key enzyme in trehalose degradation and has important functions in insect growth and chitin synthesis. Though validamycin has the potential for pest control by suppressing TRE activities, it is not known whether validamycin acts on both trehalose and chitin metabolism. TRE1 and TRE2 activities and glucose and glycogen contents decreased significantly after the injection of different doses of validamycin solution compared with the control group, while the trehalose content increased significantly. Overall, it showed that about 13 to 38% insects was appeared abnormal phenotypes, and 10 to 57% of insects died 48h after injection of solutions with different concentrations of validamycin; the chitin content also decreased significantly. Validamycin altered the relative expression levels of trehalose, glycogen and chitin metabolism-related genes by suppressing the activities of two TREs. We showed that the expression levels of three TRE and two trehalose-6-phosphate synthase (TPS) genes increased, while the expression levels of GP; CHS1 and its two transcripts, CHS1a, CHS1b; six chitinases, including Cht3, Cht4, Cht5, Cht6, Cht7, Cht9; and the HK, G6PI2, GFAT, GNPNA, PAGM1, UAP, VVL, CI and AP genes decreased significantly 48h after the injection of any validamycin concentration compared with the control group. These results demonstrate that by inhibiting the activities of two TREs, validamycin alters N. lugens chitin synthesis and degradation and affects trehalose and chitin metabolism-related gene expression. The development of TRE inhibitors may provide effective pest control in the future. Copyright © 2016 Elsevier Inc. All rights reserved.

Salinity-dependent toxicity of water-dispersible, single-walled carbon nanotubes to Japanese medaka embryos.

PubMed

Kataoka, Chisato; Nakahara, Kousuke; Shimizu, Kaori; Kowase, Shinsuke; Nagasaka, Seiji; Ifuku, Shinsuke; Kashiwada, Shosaku

2017-04-01

To investigate the effects of salinity on the behavior and toxicity of functionalized single-walled carbon nanotubes (SWCNTs), which are chemical modified nanotube to increase dispersibility, medaka embryos were exposed to non-functionalized single-walled carbon nanotubes (N-SWCNTs), water-dispersible, cationic, plastic-polymer-coated, single-walled carbon nanotubes (W-SWCNTs), or hydrophobic polyethylene glycol-functionalized, single-walled carbon nanotubes (PEG-SWCNTs) at different salinities, from freshwater to seawater. As reference nanomaterials, we tested dispersible chitin nanofiber (CNF), chitosan-chitin nanofiber (CCNF) and chitin nanocrystal (CNC, i.e. shortened CNF). Under freshwater conditions, with exposure to 10 mg l -1  W-SWCNTs, the yolk sacks of 57.8% of embryos shrank, and the remaining embryos had a reduced heart rate, eye diameter and hatching rate. Larvae had severe defects of the spinal cord, membranous fin and tail formation. These toxic effects increased with increasing salinity. Survival rates declined with increasing salinity and reached 0.0% in seawater. In scanning electron microscope images, W-SWCNTs, CNF, CCNF and CNC were adsorbed densely over the egg chorion surface; however, because of chitin's biologically harmless properties, only W-SWCNTs had toxic effects on the medaka eggs. No toxicity was observed from N-SWCNT and PEG-SWCNT exposure. We demonstrated that water dispersibility, surface chemistry, biomedical properties and salinity were important factors in assessing the aquatic toxicity of nanomaterials. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Fabrication of cationic chitin nanofiber/alginate composite materials.

PubMed

Sato, Koki; Tanaka, Kohei; Takata, Yusei; Yamamoto, Kazuya; Kadokawa, Jun-Ichi

2016-10-01

We have already found that an amidinated chitin, which was prepared by the reaction of a partially deacetylated chitin with N,N-dimethylacetamide dimethyl acetal, was converted into an amidinium chitin bicarbonate with nanofiber morphology by CO2 gas bubbling and ultrasonic treatments in water. In this study, we performed the fabrication of composite materials of such cationic chitin nanofibers with an anionic polysaccharide, sodium alginate, by ion exchange. When the amidinium chitin bicarbonate nanofiber aqueous dispersion was added to an aqueous solution of sodium alginate, the composite material was agglomerated, which was isolated by centrifugation, filtration, and lyophilization, to form a manipulatable sheet. The morphology of the resulting sheet at nano-scale was evaluated by SEM measurement. Copyright © 2016 Elsevier B.V. All rights reserved.

The effect of rumen ciliates on chitinolytic activity, chitin content and the number of fungal zoospores in the rumen fluid of sheep.

PubMed

Miltko, Renata; Bełżecki, Grzegorz; Herman, Andrzej; Kowalik, Barbara; Skomiał, Jacek

2016-12-01

The objective of this study was to investigate the effect of selected protozoa on the degradation and concentration of chitin and the numbers of fungal zoospores in the rumen fluid of sheep. Three adult ewes were fed a hay-concentrate diet, defaunated, then monofaunated with Entodinium caudatum or Diploplastron affine alone and refaunated with natural rumen fauna. The average density of the protozoa population varied from 6.1 · 10(4) (D. affine) to 42.2 · 10(4) cells/ml rumen fluid (natural rumen fauna). The inoculation of protozoa in the rumen of defaunated sheep increased the total activity of chitinolytic enzymes from 2.9 to 3.6 μmol N-acetylglucosamine/g dry matter (DM) of rumen fluid per min, the chitin concentration from 6.3 to 7.2 mg/g DM of rumen fluid and the number of fungal zoospores from 8.1 to 10.9 · 10(5) cells/ml rumen fluid. All examined indices showed diurnal variations. Ciliate population density was highest immediately prior to feeding and lowest at 4 h thereafter. The opposite effects were observed for the numbers of fungal zoospores, the chitin concentration and chitinolytic activity. Furthermore, it was found that chitin from zoospores may account for up to 95% of total microbial chitin in the rumen fluid of sheep. In summary, the examined ciliate species showed the ability of chitin degradation as well as a positive influence on the development of the ruminal fungal population.

Candida albicans Adheres to Chitin by Recognizing N-acetylglucosamine (GlcNAc).

PubMed

Ishijima, Sanae A; Yamada, Tsuyoshi; Maruyama, Naho; Abe, Shigeru

2017-01-01

The binding of Candida albicans cells to chitin was examined in a cell-binding assay. Microscopic observations indicated that both living and heat-killed Candida cells bound to chitin-coated substrates. C. albicans preferentially bound to chitin-coated plastic plates over chitosan-coated and uncoated plates. We prepared 125 I-labeled Candida cells for quantitative analysis of their binding to chitin. Heat-killed 125 I-labeled Candida cells bound to chitin-coated plates in a time-dependent manner until 1.5 hours after start of incubation at 4℃. The binding of 125 I-labeled Candida cells to chitin-coated plates was inhibited by adding unlabeled living or unlabeled heat-killed Candida cells. The binding of Candida to chitin was also reduced by addition of 25 mg/ml chitin or chitosan up to 10%. N-acetylglucosamine (GlcNAc), which is a constituent of chitin, inhibited binding of Candida to chitin in a dose-dependent manner between 12.5 and 200 mM. Glucosamine, which is a constituent of chitosan, showed no such inhibitory effect. These findings suggest that the binding of Candida to chitin may be mediated by recognition of GlcNAc.

Dopamine-Mediated Sclerotization of Regenerated Chitin in Ionic Liquid.

PubMed

Oh, Dongyeop X; Shin, Sara; Lim, Chanoong; Hwang, Dong Soo

2013-09-06

Chitin is a promising structural material for biomedical applications, due to its many advantageous properties and abundance in nature. However, its usage and development in the biomedical field have been stagnant, because of chitin's poor mechanical properties in wet conditions and the difficulties in transforming it into an applicable form. To overcome these challenges, we created a novel biomimetic chitin composite. This regenerated chitin, prepared with ionic liquid, showed improved mechanical properties in wet conditions by mimicking insect cuticle and squid beak sclerotization, i.e. , catechol-meditated cross-linking. By ionic liquid-based heat treatment, dopamine oxidation produced melanin-like compounds and dopamine-meditated cross-links without any solvent evaporation and oxidant utilization. The dopamine-meditated sclerotization increased the ultimate tensile strength (UTS) of the regenerated chitin by 2.52-fold, measured after six weeks of phosphate-buffered saline (PBS) submersion. In addition, the linear swelling ratio (LSR) of the chitin film was reduced by about 22%. This strategy raises a possibility of using regenerated chitin as an artificial hard tissue in wet conditions.

Chitin utilization by the insect-transmitted bacterium Xylella fastidiosa.

PubMed

Killiny, Nabil; Prado, Simone S; Almeida, Rodrigo P P

2010-09-01

Xylella fastidiosa is an insect-borne bacterium that colonizes xylem vessels of a large number of host plants, including several crops of economic importance. Chitin is a polysaccharide present in the cuticle of leafhopper vectors of X. fastidiosa and may serve as a carbon source for this bacterium. Biological assays showed that X. fastidiosa reached larger populations in the presence of chitin. Additionally, chitin induced phenotypic changes in this bacterium, notably increasing adhesiveness. Quantitative PCR assays indicated transcriptional changes in the presence of chitin, and an enzymatic assay demonstrated chitinolytic activity by X. fastidiosa. An ortholog of the chitinase A gene (chiA) was identified in the X. fastidiosa genome. The in silico analysis revealed that the open reading frame of chiA encodes a protein of 351 amino acids with an estimated molecular mass of 40 kDa. chiA is in a locus that consists of genes implicated in polysaccharide degradation. Moreover, this locus was also found in the genomes of closely related bacteria in the genus Xanthomonas, which are plant but not insect associated. X. fastidiosa degraded chitin when grown on a solid chitin-yeast extract-agar medium and grew in liquid medium with chitin as the sole carbon source; ChiA was also determined to be secreted. The gene encoding ChiA was cloned into Escherichia coli, and endochitinase activity was detected in the transformant, showing that the gene is functional and involved in chitin degradation. The results suggest that X. fastidiosa may use its vectors' foregut surface as a carbon source. In addition, chitin may trigger X. fastidiosa's gene regulation and biofilm formation within vectors. Further work is necessary to characterize the role of chitin and its utilization in X. fastidiosa.

A Venom Gland Extracellular Chitin-Binding-Like Protein from Pupal Endoparasitoid Wasps, Pteromalus Puparum, Selectively Binds Chitin

USDA-ARS?s Scientific Manuscript database

Chitin-binding proteins (CBPs) existed in various species and involved in different biology processes. In the present study, we cloned a full length cDNA of chitin-binding protein-like (PpCBP-like) from Pteromalus puparum, a pupal endoparasitoid of Pieris rapae. PpCBP-like encoded a 96 putative amin...

Applications of magnetic resonance spectroscopy to chitin from insect cuticles.

PubMed

Gonil, Pattarapond; Sajomsang, Warayuth

2012-11-01

Chitin is the second most abundant polysaccharide in nature after cellulose. At the present time, the main commercial sources of chitin are the crab and shrimp shells which are major waste products from the seafood industry. However, current chitin resources have some inherent problems including seasonal availability, limited supplies, and environmental pollution. As an alternative, insect cuticle is proposed as an unconventional but viable source of chitin. This review focuses on the recent sources of insect chitin and the application of various magnetic resonance spectroscopic techniques to native insect cuticles, particularly cicada sloughs and chitin extracted from insect sloughs. In addition, the physicochemical properties, isolation process, and degree of N-acetylation (DA) is reviewed and discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

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

PubMed

Chen, Wei; Qu, Mingbo; Zhou, Yong; Yang, Qing

2018-02-23

Chitin is a linear homopolymer of N -acetyl-β-d-glucosamines and a major structural component of insect cuticles. Chitin hydrolysis involves glycoside hydrolase family 18 (GH18) chitinases. In insects, chitin hydrolysis is essential for periodic shedding of the old cuticle ecdysis and proceeds via a pathway different from that in the well studied bacterial chitinolytic system. Group II chitinase (ChtII) is a widespread chitinolytic enzyme in insects and contains the greatest number of catalytic domains and chitin-binding domains among chitinases. In Lepidopterans, ChtII and two other chitinases, ChtI and Chi-h, are essential for chitin hydrolysis. Although ChtI and Chi-h have been well studied, the role of ChtII remains elusive. Here, we investigated the structure and enzymology of Of ChtII, a ChtII derived from the insect pest Ostrinia furnacalis We present the crystal structures of two catalytically active domains of Of ChtII, Of ChtII-C1 and Of ChtII-C2, both in unliganded form and complexed with chitooligosaccharide substrates. We found that Of ChtII-C1 and Of ChtII-C2 both possess long, deep substrate-binding clefts with endochitinase activities. Of ChtII exhibited structural characteristics within the substrate-binding cleft similar to those in Of Chi-h and Of ChtI. However, Of ChtII lacked structural elements favoring substrate binding beyond the active sites, including an extra wall structure present in Of Chi-h. Nevertheless, the numerous domains in Of ChtII may compensate for this difference; a truncation containing one catalytic domain and three chitin-binding modules ( Of ChtII-B4C1) displayed activity toward insoluble polymeric substrates that was higher than those of Of Chi-h and Of ChtI. Our observations provide the last piece of the puzzle of chitin hydrolysis in insects. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Elucidating the influence of polymorph-dependent interfacial solvent structuring at chitin surfaces.

PubMed

Brown, Aaron H; Walsh, Tiffany R

2016-10-20

Interfacial solvent structuring is thought to be influential in mediating the adsorption of biomolecules at aqueous materials interfaces. However, despite the enormous potential for exploitation of aqueous chitin interfaces in industrial, medical and drug-delivery applications, little is known at the molecular-level about such interfacial solvent structuring for chitin. Here we use molecular simulation to predict the structure of the [100] and [010] interfaces of α-chitin and β-chitin dihydrate in contact with liquid water and saline solution. We find the α-chitin [100] interface supports lateral high-density regions in the first water layer at the interface, which are also present, but not as pronounced, for β-chitin. The lateral structuring of interfacial ions at the saline/chitin interface is also more pronounced for α-chitin compared with β-chitin. Our findings provide a foundation for the systematic design of biomolecules with selective binding affinity for different chitin polymorphs. Copyright © 2016 Elsevier Ltd. All rights reserved.

The occurrence of chitin in the hemocytes of invertebrates

PubMed Central

Heath-Heckman, Elizabeth A.C.; McFall-Ngai, Margaret J.

2011-01-01

The light-organ symbiosis of Euprymna scolopes, the Hawaiian bobtail squid, is a useful model for the study of animal–microbe interactions. Recent analyses have demonstrated that chitin breakdown products play a role in communication between E. scolopes and its bacterial symbiont Vibrio fischeri. In this study, we sought to determine the source of chitin in the symbiotic organ. We used a commercially available chitin-binding protein (CBP) conjugated to fluorescein to label the polymeric chitin in host tissues. Confocal microscopy revealed that the only cells in contact with the symbionts that labeled with the probe were the macrophage-like hemocytes, which traffic into the light-organ crypts where the bacteria reside. Labeling of extracted hemocytes by CBP was markedly decreased following treatment with purified chitinase, providing further evidence that the labeled molecule is polymeric chitin. Further, CBP-positive areas co-localized with both a halide peroxidase antibody and Lysotracker, a lysosomal marker, suggesting that the chitin-like biomolecule occurs in the lysosome or acidic vacuoles. Reverse transcriptase polymerase chain reaction (PCR) of hemocytes revealed mRNA coding for a chitin synthase, suggesting that the hemocytes synthesize chitin de novo. Finally, upon surveying blood cells from other invertebrate species, we observed CBP-positive regions in all granular blood cells examined, suggesting that this feature is a shared character among the invertebrates; the vertebrate blood cells that we sampled did not label with CBP. Although the function of the chitin-like material remains undetermined, its presence and subcellular location in invertebrate hemocytes suggests a conserved role for this polysaccharide in the immune system of diverse animals. PMID:21723107

Degradation and mineralization of chitin in an estuary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyer, J.

1987-01-01

A method for measuring microbial degradation and mineralization of radiolabeled native chitin is described. /sup 14/C-labeled chitin was synthesized in vivo by injecting shed blue crabs (Callinectes sapidus) with N-acetyl-D-(/sup 14/C)-glucosamine, allowing for its incorporation into the exoskeleton. Rates of chitin degradation and mineralization in estuarine water and sediments were determined as functions of temperature, inoculum source, and oxygen condition. Significant differences in rates between temperature treatments were evident. Q/sub 10/ values ranged from 1.2 to 2.5 for water and sediment, respectively. Increased incubation temperature also resulted in decreased lag times before onset of chitinoclastic bacterial growth and chitin degradation.more » The anaerobic pathway of chitin decomposition by chitinoclastic bacteria was examined with an emphasis on end product coupling to other bacterial types. Actively growing chitinoclastic bacterial isolates produced primarily acetate, hydrogen, and carbon dioxide in broth culture.« less

Crab shell chitin whiskers reinforced natural rubber nanocomposites. 3. Effect of chemical modification of chitin whiskers.

PubMed

Gopalan Nair, Kalaprasad; Dufresne, Alain; Gandini, Alessandro; Belgacem, Mohamed Naceur

2003-01-01

The purpose of this study was to chemically modify the surface of chitin whiskers and to investigate the effect of the incorporation of these modified whiskers into a natural rubber (NR) matrix on the properties of the ensuing nanocomposite. Different chemical coupling agents were tested, namely, phenyl isocyanate (PI), alkenyl succinic anhydride (ASA) (Accosize 18 from American Cyanamid), and 3-isopropenyl-alpha,alpha'-dimethylbenzyl isocyanate (TMI). The extent of chemical modification was evaluated by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and surface energy analysis. After chemical modification, nanocomposite films were obtained using a toluene natural rubber solution in which the whiskers were dispersed. Their mechanical properties were found to be inferior to those of unmodified chitin/NR composites presented in our previous study. In fact, even though there is an increase in filler-matrix interaction as a result of chemical modification of the chitin whiskers, this does not contribute to the improvement in the mechanical properties of the resulting nanocomposite. It is concluded that this loss of performance is due to the partial destruction of the three-dimensional network of chitin whiskers assumed to be present in the unmodified composites.

A chitin-like component in Aedes aegypti eggshells, eggs and ovaries.

PubMed

Moreira, Mônica F; Dos Santos, Amanda S; Marotta, Humberto R; Mansur, Juliana F; Ramos, Isabela B; Machado, Ednildo A; Souza, Gustavo H M F; Eberlin, Marcos N; Kaiser, Carlos R; Kramer, Karl J; Muthukrishnan, Subbaratnam; Vasconcellos, Ana Maria H

2007-12-01

An insoluble white substance was prepared from extracts of eggshells of Aedes aegypti, the yellow fever mosquito and dengue vector. Its infrared and proton NMR spectra were similar to that of standard commercial chitin. This putative chitin-like material, also obtained from ovaries, newly laid and dark eggs, was hydrolyzed in acid and a major product was identified by HPLC to be glucosamine. The eggshell acid hydrolysate was also analyzed by ESI-MS and an ion identical to a glucosamine monoprotonated species was detected. The presence of chitin was also analyzed during different developmental stages of the ovary using a fluorescent microscopy technique and probes specific for chitin. The results showed that a chitin-like material accumulates in oocytes during oogenesis. Streptomyces griseus chitinase pre-treatment of oocytes greatly reduced the chitin-derived fluorescence. Chitinase activity was detected in newborn larvae and eggs prior to hatching. Feeding experiments indicated that the chitin synthesis inhibitor lufenuron inhibited chitin synthesis, either when mosquitoes were allowed to feed directly on lufenuron-treated chickens or when an artificial feeding system was used. Lufenuron inhibited egg hatch, larval development and reduced mosquito viability. These data demonstrate for the first time that (1) a chitin-like material is present in A. aegypti eggs, ovaries and eggshells; (2) a chitin synthesis inhibitor can be used to inhibit mosquito oogenesis; and (3) chitin synthesis inhibitors have potential for controlling mosquito populations.

Chitin and chitinase: Role in pathogenicity, allergenicity and health.

PubMed

Patel, Seema; Goyal, Arun

2017-04-01

Chitin, a polysaccharide with particular abundance in fungi, nematodes and arthropods is immunogenic. It acts as a threat to other organisms, to tackle which they have been endowed with chitinase enzyme. Even if this enzyme is not present in all organisms, they possess proteins having chitin-binding domain(s) (ChtBD). Many lethal viruses like Ebola, and HCV (Hepatitis C virus) have these domains to manipulate their carriers and target organisms. In keeping with the basic rule of survival, the self-origin (own body component) chitins and chitinases are protective, but that of non-self origin (from other organisms) are detrimental to health. The exogenous chitins and chitinases provoke human innate immunity to generate a deluge of inflammatory cytokines, which injure organs (leading to asthma, atopic dermatitis etc.), and in persistent situations lead to death (multiple sclerosis, systemic lupus erythromatosus (SLE), cancer, etc.). Unfortunately, chitin-chitinase-stimulated hypersensitivity is a common cause of occupational allergy. On the other hand, chitin, and its deacetylated derivative chitosan are increasingly proving useful in pharmaceutical, agriculture, and biocontrol applications. This critical review discusses the complex nexus of chitin and chitinase and assesses both their pathogenic as well as utilitarian aspects. Copyright © 2017 Elsevier B.V. All rights reserved.

Dopamine-Mediated Sclerotization of Regenerated Chitin in Ionic Liquid

PubMed Central

Oh, Dongyeop X.; Shin, Sara; Lim, Chanoong; Hwang, Dong Soo

2013-01-01

Chitin is a promising structural material for biomedical applications, due to its many advantageous properties and abundance in nature. However, its usage and development in the biomedical field have been stagnant, because of chitin’s poor mechanical properties in wet conditions and the difficulties in transforming it into an applicable form. To overcome these challenges, we created a novel biomimetic chitin composite. This regenerated chitin, prepared with ionic liquid, showed improved mechanical properties in wet conditions by mimicking insect cuticle and squid beak sclerotization, i.e., catechol-meditated cross-linking. By ionic liquid-based heat treatment, dopamine oxidation produced melanin-like compounds and dopamine-meditated cross-links without any solvent evaporation and oxidant utilization. The dopamine-meditated sclerotization increased the ultimate tensile strength (UTS) of the regenerated chitin by 2.52-fold, measured after six weeks of phosphate-buffered saline (PBS) submersion. In addition, the linear swelling ratio (LSR) of the chitin film was reduced by about 22%. This strategy raises a possibility of using regenerated chitin as an artificial hard tissue in wet conditions. PMID:28788308

Chitin, Chitosan, and Its Derivatives for Wound Healing: Old and New Materials

PubMed Central

Azuma, Kazuo; Izumi, Ryotaro; Osaki, Tomohiro; Ifuku, Shinsuke; Morimoto, Minoru; Saimoto, Hiroyuki; Minami, Saburo; Okamoto, Yoshiharu

2015-01-01

Chitin (β-(1-4)-poly-N-acetyl-d-glucosamine) is widely distributed in nature and is the second most abundant polysaccharide after cellulose. It is often converted to its more deacetylated derivative, chitosan. Previously, many reports have indicated the accelerating effects of chitin, chitosan, and its derivatives on wound healing. More recently, chemically modified or nano-fibrous chitin and chitosan have been developed, and their effects on wound healing have been evaluated. In this review, the studies on the wound-healing effects of chitin, chitosan, and its derivatives are summarized. Moreover, the development of adhesive-based chitin and chitosan are also described. The evidence indicates that chitin, chitosan, and its derivatives are beneficial for the wound healing process. More recently, it is also indicate that some nano-based materials from chitin and chitosan are beneficial than chitin and chitosan for wound healing. Clinical applications of nano-based chitin and chitosan are also expected. PMID:25780874

Chitin biosynthesis: does it involve a lipid-bound intermediate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bade, M.L.

1983-01-01

In plants and animals, mechanical support is provided by insoluble extracellular fibers of high molecular weight which, in many invertebrates and fungi, consist in part of the nitrogen-containing carbohydrate chitin. At least in animals, chitin may be covalently bonded to protein. This possibility has given rise to the persistent search for a lipid-bound intermediate in chitin biosynthesis, since for certain glycoproteins such involvement is well established. Cell-free chitin synthetase systems from yeasts have been prepared, purified, and to some extent characterized. For such systems, in the cases where the product has been unequivocally identified as chitin, involvement of a lipid-boundmore » intermediate is most unlikely. Chitin synthesis by particulate cell-free preparations has been claimed for both crustaceans and insects. Careful inspection of the evidence in the latter instances reveals either that the synthetase is probably of microorganismic origin, or that the available results do not convincingly support the conclusions drawn from them. Semi-in vitro work involving short- or longer-term culture of epithelial cells synthesizing chitin has been done successfully in a number of laboratories. In cases where the question of lipid-bound intermediates has been addressed, the evidence has tended to militate against such involvement in insects and for it in crustaceans, but the evidence is as yet inconclusive. Further work is needed.« less

Chitin Utilization by the Insect-Transmitted Bacterium Xylella fastidiosa▿ †

PubMed Central

Killiny, Nabil; Prado, Simone S.; Almeida, Rodrigo P. P.

2010-01-01

Xylella fastidiosa is an insect-borne bacterium that colonizes xylem vessels of a large number of host plants, including several crops of economic importance. Chitin is a polysaccharide present in the cuticle of leafhopper vectors of X. fastidiosa and may serve as a carbon source for this bacterium. Biological assays showed that X. fastidiosa reached larger populations in the presence of chitin. Additionally, chitin induced phenotypic changes in this bacterium, notably increasing adhesiveness. Quantitative PCR assays indicated transcriptional changes in the presence of chitin, and an enzymatic assay demonstrated chitinolytic activity by X. fastidiosa. An ortholog of the chitinase A gene (chiA) was identified in the X. fastidiosa genome. The in silico analysis revealed that the open reading frame of chiA encodes a protein of 351 amino acids with an estimated molecular mass of 40 kDa. chiA is in a locus that consists of genes implicated in polysaccharide degradation. Moreover, this locus was also found in the genomes of closely related bacteria in the genus Xanthomonas, which are plant but not insect associated. X. fastidiosa degraded chitin when grown on a solid chitin-yeast extract-agar medium and grew in liquid medium with chitin as the sole carbon source; ChiA was also determined to be secreted. The gene encoding ChiA was cloned into Escherichia coli, and endochitinase activity was detected in the transformant, showing that the gene is functional and involved in chitin degradation. The results suggest that X. fastidiosa may use its vectors' foregut surface as a carbon source. In addition, chitin may trigger X. fastidiosa's gene regulation and biofilm formation within vectors. Further work is necessary to characterize the role of chitin and its utilization in X. fastidiosa. PMID:20656858

Preparation of monolithic silica-chitin composite under extreme biomimetic conditions.

PubMed

Bazhenov, Vasilii V; Wysokowski, Marcin; Petrenko, Iaroslav; Stawski, Dawid; Sapozhnikov, Philipp; Born, René; Stelling, Allison L; Kaiser, Sabine; Jesionowski, Teofil

2015-05-01

Chitin is a widespread renewable biopolymer that is extensively distributed in the natural world. The high thermal stability of chitin provides an opportunity to develop novel inorganic-organic composites under hydrothermal synthesis conditions in vitro. For the first time, in this work we prepared monolithic silica-chitin composite under extreme biomimetic conditions (80°C and pH 1.5) using three dimensional chitinous matrices isolated from the marine sponge Aplysina cauliformis. The resulting material was studied using light and fluorescence microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy. A mechanism for the silica-chitin interaction after exposure to these hydrothermal conditions is proposed and discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Chitin-induced and CHITIN ELICITOR RECEPTOR KINASE1 (CERK1) phosphorylation-dependent endocytosis of Arabidopsis thaliana LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE5 (LYK5).

PubMed

Erwig, Jan; Ghareeb, Hassan; Kopischke, Michaela; Hacke, Ronja; Matei, Alexandra; Petutschnig, Elena; Lipka, Volker

2017-07-01

To detect potential pathogens, plants perceive the fungal polysaccharide chitin through receptor complexes containing lysin motif receptor-like kinases (LysM-RLKs). To investigate the ligand-induced spatial dynamics of chitin receptor components, we studied the subcellular behaviour of two Arabidopsis thaliana LysM-RLKs involved in chitin signalling, CHITIN ELICITOR RECEPTOR KINASE1 (CERK1) and LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE5. We performed standard and quantitative confocal laser scanning microscopy on stably transformed A. thaliana plants expressing fluorescently tagged CERK1 and LYK5 from their native promoters. Microscopy approaches were complemented by biochemical analyses in plants and in vitro. Both CERK1 and LYK5 localized to the plasma membrane and showed constitutive endomembrane trafficking. After chitin treatment, however, CERK1 remained at the plasma membrane while LYK5 relocalized into mobile intracellular vesicles. Detailed analyses revealed that chitin perception transiently induced the internalization of LYK5 into late endocytic compartments. Plants that lacked CERK1 or expressed an enzymatically inactive CERK1 variant did not exhibit chitin-induced endocytosis of LYK5. CERK1 could phosphorylate LYK5 in vitro and chitin treatment induced CERK1-dependent phosphorylation of LYK5 in planta. Our results suggest that chitin-induced phosphorylation by CERK1 triggers LYK5 internalization. Thus, our work identifies phosphorylation as a key regulatory step in endocytosis of plant RLKs and also provides evidence for receptor complex dissociation after ligand perception. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Chitins and chitosans as immunoadjuvants and non-allergenic drug carriers.

PubMed

Muzzarelli, Riccardo A A

2010-02-21

Due to the fact that some individuals are allergic to crustaceans, the presumed relationship between allergy and the presence of chitin in crustaceans has been investigated. In vivo, chitin is part of complex structures with other organic and inorganic compounds: in arthropods chitin is covalently linked to proteins and tanned by quinones, in fungi it is covalently linked to glucans, while in bacteria chitin is diversely combined according to Gram(+/-) classification. On the other hand, isolated, purified chitin is a plain polysaccharide that, at the nano level, presents itself as a highly associated structure, recently refined in terms of regularity, nature of bonds, crystallinity degree and unusual colloidal behavior. Chitins and modified chitins exert a number of beneficial actions, i.e., (i) they stimulate macrophages by interacting with receptors on the macrophage surface that mediate the internalization of chitin particles to be degraded by lysozyme and N-acetyl-beta-glucosaminidase (such as Nod-like, Toll-like, lectin, Dectin-1, leukotriene 134 and mannose receptors); (ii) the macrophages produce cytokines and other compounds that confer non-specific host resistance against bacterial and viral infections, and anti-tumor activity; (iii) chitin is a strong Th1 adjuvant that up-regulates Th1 immunity induced by heat-killed Mycobacterium bovis, while down- regulating Th2 immunity induced by mycobacterial protein; (iv) direct intranasal application of chitin microparticles into the lung was also able to significantly down-regulate allergic response to Dermatophagoids pteronyssinus and Aspergillus fumigatus in a murine model of allergy; (v) chitin microparticles had a beneficial effect in preventing and treating histopathologic changes in the airways of asthmatic mice; (vi) authors support the fact that chitin depresses the development of adaptive type 2 allergic responses. Since the expression of chitinases, chitrotriosidase and chitinase-like proteins is greatly

Ultrasound stimulated release of gallic acid from chitin hydrogel matrix.

PubMed

Jiang, Huixin; Kobayashi, Takaomi

2017-06-01

Ultrasound (US) stimulated drug release was examined in this study using a chitin hydrogel matrix loaded with gallic acid (GA), a drug used for wound healing and anticancer. Using phase inversion, GA-chitin hydrogels were prepared from chitin-dimethylacetamide (DMAc)/lithium chloride (LiCl) solution in the presence of GA, with 24h exposure of the solution to water vapor. The GA release from the GA-chitin hydrogel was examined under different US powers of 0-30W at 43kHz. The effects of GA loading amounts in the hydrogels (0.54, 0.43, and 0.25mg/cm 3 ) and chitin concentrations (0.1, 0.5, and 1wt%) on the release behaviors were recorded under 43kHz US exposure at 30W. Results show that US accelerated the release efficiencies for all samples. Furthermore, the release efficiency increased concomitantly with increasing US power, GA loading amount, and decrease of the chitin concentration. The highest release rate of 0.74μg/mL·min was obtained from 0.54mg/cm 3 of GA-loaded hydrogel fabricated from a 0.1wt% chitin mixture solution under 43kHz US exposure at 30W: nine times higher than that of the sample without US exposure. The hydrogel viscoelasticity demonstrated that the US irradiation rigidified the material. FT-IR showed that US can break the hydrogen bonds in the GA-chitin hydrogels. Copyright © 2017 Elsevier B.V. All rights reserved.

Multifilament cellulose/chitin blend yarn spun from ionic liquids.

PubMed

Mundsinger, Kai; Müller, Alexander; Beyer, Ronald; Hermanutz, Frank; Buchmeiser, Michael R

2015-10-20

Cellulose and chitin, both biopolymers, decompose before reaching their melting points. Therefore, processing these unmodified biopolymers into multifilament yarns is limited to solution chemistry. Especially the processing of chitin into fibers is rather limited to distinctive, often toxic or badly removable solvents often accompanied by chemical de-functionalization to chitosan (degree of acetylation, DA, <50%). This work proposes a novel method for the preparation of cellulose/chitin blend fibers using ionic liquids (ILs) as gentle, removable, recyclable and non-deacetylating solvents. Chitin and cellulose are dissolved in ethylmethylimidazolium propionate ([C2mim](+)[OPr](-)) and the obtained one-pot spinning dope is used to produce multifilament fibers by a continuous wet-spinning process. Both the rheology of the corresponding spinning dopes and the structural and physical properties of the obtained fibers have been determined for different biopolymer ratios. With respect to medical or hygienic application, the cellulose/chitin blend fiber show enhanced water retention capacity compared to pure cellulose fibers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Maternal control of seed oil content in Brassica napus: the role of silique wall photosynthesis.

PubMed

Hua, Wei; Li, Rong-Jun; Zhan, Gao-Miao; Liu, Jing; Li, Jun; Wang, Xin-Fa; Liu, Gui-Hua; Wang, Han-Zhong

2012-02-01

Seed oil content is an important agronomic trait in rapeseed. However, our understanding of the regulatory processes controlling oil accumulation is still limited. Using two rapeseed lines (zy036 and 51070) with contrasting oil content, we found that maternal genotype greatly affects seed oil content. Genetic and physiological evidence indicated that difference in the local and tissue-specific photosynthetic activity in the silique wall (a maternal tissue) was responsible for the different seed oil contents. This effect was mimicked by in planta manipulation of silique wall photosynthesis. Furthermore, the starch content and expression of the important lipid synthesis regulatory gene WRINKLED1 in developing seeds were linked with silique wall photosynthetic activity. 454 pyrosequencing was performed to explore the possible molecular mechanism for the difference in silique wall photosynthesis between zy036 and 51070. Interestingly, the results suggested that photosynthesis-related genes were over-represented in both total silique wall expressed genes and genes that were differentially expressed between genotypes. A potential regulatory mechanism for elevated photosynthesis in the zy036 silique wall is proposed on the basis of knowledge from Arabidopsis. Differentially expressed ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco)-related genes were used for further investigations. Oil content correlated closely with BnRBCS1A expression levels and Rubisco activities in the silique wall, but not in the leaf. Taken together, our results highlight an important role of silique wall photosynthesis in the regulation of seed oil content in terms of maternal effects. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

Chitin synthases are required for survival, fecundity and egg hatch in the red flour beetle, Tribolium castaneum.

PubMed

Arakane, Yasuyuki; Specht, Charles A; Kramer, Karl J; Muthukrishnan, Subbaratnam; Beeman, Richard W

2008-10-01

The synthesis of chitin, the beta-1,4-linked polymer of N-acetylglucosamine, is catalyzed by chitin synthase (CHS). Chitin is essential for the structural integrity of the exoskeletal cuticle and midgut peritrophic membrane (PM) of insects. To study the functions of the two chitin synthase genes, TcCHS-A and TcCHS-B, during embryonic and adult development in the red flour beetle, Tribolium castaneum, RNA interference (RNAi) experiments were carried out. When dsRNA for TcCHS-A was injected into male or female pharate adults, all insects died 5-7 d after the adult molt, and the females failed to oviposit prior to death. When dsTcCHS-A was injected into young adults 1-2 d post-eclosion, a similar lethal phenotype was obtained after 5 d and no oviposition occurred. When dsTcCHS-A injections were delayed until after adult maturation (7-10 d post-eclosion), the treated females did oviposit and the resulting embryos appeared to develop normally. However, the chitin content of the eggs was dramatically reduced, the embryos became twisted and enlarged, and the eggs did not hatch. Adults treated with dsRNA for TcCHS-B exhibited little or no chitin in their PM and died about 2 wk after injection. None of the TcCHS-B-treated females oviposited, which was probably a secondary effect caused by starvation. These results extend our previous findings that CHS genes are required for all types of molt. The present study also demonstrates that these genes have additional roles in embryonic and adult development.

Deciphering the Genetic Programme Triggering Timely and Spatially-Regulated Chitin Deposition

PubMed Central

Rotstein, Bárbara; Casali, Andreu; Llimargas, Marta

2015-01-01

Organ and tissue formation requires a finely tuned temporal and spatial regulation of differentiation programmes. This is necessary to balance sufficient plasticity to undergo morphogenesis with the acquisition of the mature traits needed for physiological activity. Here we addressed this issue by analysing the deposition of the chitinous extracellular matrix of Drosophila, an essential element of the cuticle (skin) and respiratory system (tracheae) in this insect. Chitin deposition requires the activity of the chitin synthase Krotzkopf verkehrt (Kkv). Our data demonstrate that this process equally requires the activity of two other genes, namely expansion (exp) and rebuf (reb). We found that Exp and Reb have interchangeable functions, and in their absence no chitin is produced, in spite of the presence of Kkv. Conversely, when Kkv and Exp/Reb are co-expressed in the ectoderm, they promote chitin deposition, even in tissues normally devoid of this polysaccharide. Therefore, our results indicate that both functions are not only required but also sufficient to trigger chitin accumulation. We show that this mechanism is highly regulated in time and space, ensuring chitin accumulation in the correct tissues and developmental stages. Accordingly, we observed that unregulated chitin deposition disturbs morphogenesis, thus highlighting the need for tight regulation of this process. In summary, here we identify the genetic programme that triggers the timely and spatially regulated deposition of chitin and thus provide new insights into the extracellular matrix maturation required for physiological activity. PMID:25617778

Soil Bacterial Community Shifts after Chitin Enrichment: An Integrative Metagenomic Approach

PubMed Central

Jacquiod, Samuel; Franqueville, Laure; Cécillon, Sébastien; M. Vogel, Timothy; Simonet, Pascal

2013-01-01

Chitin is the second most produced biopolymer on Earth after cellulose. Chitin degrading enzymes are promising but untapped sources for developing novel industrial biocatalysts. Hidden amongst uncultivated micro-organisms, new bacterial enzymes can be discovered and exploited by metagenomic approaches through extensive cloning and screening. Enrichment is also a well-known strategy, as it allows selection of organisms adapted to feed on a specific compound. In this study, we investigated how the soil bacterial community responded to chitin enrichment in a microcosm experiment. An integrative metagenomic approach coupling phylochips and high throughput shotgun pyrosequencing was established in order to assess the taxonomical and functional changes in the soil bacterial community. Results indicate that chitin enrichment leads to an increase of Actinobacteria, γ-proteobacteria and β-proteobacteria suggesting specific selection of chitin degrading bacteria belonging to these classes. Part of enriched bacterial genera were not yet reported to be involved in chitin degradation, like the members from the Micrococcineae sub-order (Actinobacteria). An increase of the observed bacterial diversity was noticed, with detection of specific genera only in chitin treated conditions. The relative proportion of metagenomic sequences related to chitin degradation was significantly increased, even if it represents only a tiny fraction of the sequence diversity found in a soil metagenome. PMID:24278158

Anti-Icing Chitin Coating System Development

DTIC Science & Technology

1990-06-30

chitosan additives plus eight control samples were selected for the initial fungi testing. AsDeraillus oryzae (ATCC No. 10196) and Aspergillus niger...Task II work will determine the chitin/chitosan- paint suspensions standard ASTM test characteristics . Tasks III, IV and V will then center on the...five minutes to determine if full exposure of the chitin would increase the icephobic characteristics . Samples P2- BT-100 & 200-D and S7-BT-100 & 200-D

Chitin and carbon nanotube composites as biocompatible scaffolds for neuron growth

NASA Astrophysics Data System (ADS)

Singh, Nandita; Chen, Jinhu; Koziol, Krzysztof K.; Hallam, Keith R.; Janas, Dawid; Patil, Avinash J.; Strachan, Ally; G. Hanley, Jonathan; Rahatekar, Sameer S.

2016-04-01

The design of biocompatible implants for neuron repair/regeneration ideally requires high cell adhesion as well as good electrical conductivity. Here, we have shown that plasma-treated chitin carbon nanotube composite scaffolds show very good neuron adhesion as well as support of synaptic function of neurons. The addition of carbon nanotubes to a chitin biopolymer improved the electrical conductivity and the assisted oxygen plasma treatment introduced more oxygen species onto the chitin nanotube scaffold surface. Neuron viability experiments showed excellent neuron attachment onto plasma-treated chitin nanotube composite scaffolds. The support of synaptic function was evident on chitin/nanotube composites, as confirmed by PSD-95 staining. The biocompatible and electrically-conducting chitin nanotube composite scaffold prepared in this study can be used for in vitro tissue engineering of neurons and, potentially, as an implantable electrode for stimulation and repair of neurons.

Chitin and carbon nanotube composites as biocompatible scaffolds for neuron growth.

PubMed

Singh, Nandita; Chen, Jinhu; Koziol, Krzysztof K; Hallam, Keith R; Janas, Dawid; Patil, Avinash J; Strachan, Ally; G Hanley, Jonathan; Rahatekar, Sameer S

2016-04-21

The design of biocompatible implants for neuron repair/regeneration ideally requires high cell adhesion as well as good electrical conductivity. Here, we have shown that plasma-treated chitin carbon nanotube composite scaffolds show very good neuron adhesion as well as support of synaptic function of neurons. The addition of carbon nanotubes to a chitin biopolymer improved the electrical conductivity and the assisted oxygen plasma treatment introduced more oxygen species onto the chitin nanotube scaffold surface. Neuron viability experiments showed excellent neuron attachment onto plasma-treated chitin nanotube composite scaffolds. The support of synaptic function was evident on chitin/nanotube composites, as confirmed by PSD-95 staining. The biocompatible and electrically-conducting chitin nanotube composite scaffold prepared in this study can be used for in vitro tissue engineering of neurons and, potentially, as an implantable electrode for stimulation and repair of neurons.

Chitin: a cell-surface component of Phytomonas françai.

PubMed

Nakamura, C V; Esteves, M J; Andrade, A F; Alviano, C S; de Souza, W; Angluster, J

1993-01-01

The occurrence of chitin as a structural component of the surface of the phytopathogenic protozoan Phytomonas françai was demonstrated by paper and gas-liquid chromatographic analysis of the products of enzymatic and chemical hydrolysis of alkali-resistant polysaccharides, lectin binding, glycosidase digestion, and infrared spectra. Chitin was characterized by its insolubility in hot alkali and chromatographic immobility as well as by the release of glucosamine on hydrolysis with strong acid and of N-acetylglucosamine (GlcNAc) on hydrolysis with chitinase. The presence of chitin was also shown directly by binding of wheat-germ agglutinin (WGA), which recognizes GlcNAc units, to the parasite surface. Fluorescein-labeled WGA binding was completely abolished by treatment with chitinase. This effect was specific since it could be prevented by incubating the enzyme with chitin before treatment of the phytomonads. These findings indicate that chitin is an exposed cell-surface polysaccharide in Phytomonas françai. The data were confirmed by the infrared spectrum of an alkali-insoluble residue, which showed a pattern typical of chitin.

Chitin Scaffolds in Tissue Engineering

PubMed Central

Jayakumar, Rangasamy; Chennazhi, Krishna Prasad; Srinivasan, Sowmya; Nair, Shantikumar V.; Furuike, Tetsuya; Tamura, Hiroshi

2011-01-01

Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine. PMID:21673928

Wet spinning of fibers made of chitosan and chitin nanofibrils.

PubMed

Yudin, Vladimir E; Dobrovolskaya, Irina P; Neelov, Igor M; Dresvyanina, Elena N; Popryadukhin, Pavel V; Ivan'kova, Elena M; Elokhovskii, Vladimir Yu; Kasatkin, Igor A; Okrugin, Boris M; Morganti, Pierfrancesco

2014-08-08

Biocompatible and bioresorbable composite fibers consisting of chitosan filled with anisotropic chitin nanofibrils with the length of 600-800 nm and cross section of about 11-12 nm as revealed by SEM and XRD were prepared by coagulation. Both chitin and chitosan components of the composite fibers displayed preferred orientations. Orientation of chitosan molecules induced by chitin nanocrystallites was confirmed by molecular modeling. The incorporation of 0.1-0.3 wt.% of chitin nanofibrils into chitosan matrix led to an increase in strength and Young modulus of the composite fibers. Copyright © 2014 Elsevier Ltd. All rights reserved.

Emerging chitin and chitosan nanofibrous materials for biomedical applications

NASA Astrophysics Data System (ADS)

Ding, Fuyuan; Deng, Hongbing; Du, Yumin; Shi, Xiaowen; Wang, Qun

2014-07-01

Over the past several decades, we have witnessed significant progress in chitosan and chitin based nanostructured materials. The nanofibers from chitin and chitosan with appealing physical and biological features have attracted intense attention due to their excellent biological properties related to biodegradability, biocompatibility, antibacterial activity, low immunogenicity and wound healing capacity. Various methods, such as electrospinning, self-assembly, phase separation, mechanical treatment, printing, ultrasonication and chemical treatment were employed to prepare chitin and chitosan nanofibers. These nanofibrous materials have tremendous potential to be used as drug delivery systems, tissue engineering scaffolds, wound dressing materials, antimicrobial agents, and biosensors. This review article discusses the most recent progress in the preparation and application of chitin and chitosan based nanofibrous materials in biomedical fields.

Systematic genetic dissection of chitin degradation and uptake in Vibrio cholerae.

PubMed

Hayes, Chelsea A; Dalia, Triana N; Dalia, Ankur B

2017-10-01

Vibrio cholerae is a natural resident of the aquatic environment, where a common nutrient is the chitinous exoskeletons of microscopic crustaceans. Chitin utilization requires chitinases, which degrade this insoluble polymer into soluble chitin oligosaccharides. These oligosaccharides also serve as an inducing cue for natural transformation in Vibrio species. There are 7 predicted endochitinase-like genes in the V. cholerae genome. Here, we systematically dissect the contribution of each gene to growth on chitin as well as induction of natural transformation. Specifically, we created a strain that lacks all 7 putative chitinases and from this strain, generated a panel of strains where each expresses a single chitinase. We also generated expression plasmids to ectopically express all 7 chitinases in our chitinase deficient strain. Through this analysis, we found that low levels of chitinase activity are sufficient for natural transformation, while growth on insoluble chitin as a sole carbon source requires more robust and concerted chitinase activity. We also assessed the role that the three uptake systems for the chitin degradation products GlcNAc, (GlcNAc) 2 and (GlcN) 2 , play in chitin utilization and competence induction. Cumulatively, this study provides mechanistic details for how this pathogen utilizes chitin to thrive and evolve in its environmental reservoir. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Benzoylurea Chitin Synthesis Inhibitors.

PubMed

Sun, Ranfeng; Liu, Chunjuan; Zhang, Hao; Wang, Qingmin

2015-08-12

Benzoylurea chitin synthesis inhibitors are widely used in integrated pest management (IPM) and insecticide resistance management (IRM) programs due to their low toxicity to mammals and predatory insects. In the past decades, a large number of benzoylurea derivatives have been synthesized, and 15 benzoylurea chitin synthesis inhibitors have been commercialized. This review focuses on the history of commercial benzolyphenylureas (BPUs), synthetic methods, structure-activity relationships (SAR), action mechanism research, environmental behaviors, and ecotoxicology. Furthermore, their disadvantages of high risk to aquatic invertebrates and crustaceans are pointed out. Finally, we propose that the para-substituents at anilide of benzoylphenylureas should be the functional groups, and bipartite model BPU analogues are discussed in an attempt to provide new insight for future development of BPUs.

Nature-Inspired One-Step Green Procedure for Enhancing the Antibacterial and Antioxidant Behavior of a Chitin Film: Controlled Interfacial Assembly of Tannic Acid onto a Chitin Film.

PubMed

Wang, Yuntao; Li, Jing; Li, Bin

2016-07-20

The final goal of this study was to develop antimicrobial food-contact materials based on a natural phenolic compound (tannic acid) and chitin, which is the second most abundant polysaccharide on earth, using an interfacial assembly approach. Chitin film has poor antibacterial and antioxidant ability, which limits its application in industrial fields such as active packaging. Therefore, in this study, a novel one-step green procedure was applied to introduce antibacterial and antioxidant properties into a chitin film simultaneously by incorporation of tannic acid into the chitin film through interfacial assembly. The antibacterial and antioxidant behavior of chitin film has been greatly enhanced. Hydrogen bonds and hydrophobic interaction were found to be the main driving forces for interfacial assembly. Therefore, controlled interfacial assembly of tannic acid onto a chitin film demonstrated a good way to develop functional materials that can be potentially applied in industry.

Protective Effect of Chitin Urocanate Nanofibers against Ultraviolet Radiation

PubMed Central

Ito, Ikuko; Yoneda, Toshikazu; Omura, Yoshihiko; Osaki, Tomohiro; Ifuku, Shinsuke; Saimoto, Hiroyuki; Azuma, Kazuo; Imagawa, Tomohiro; Tsuka, Takeshi; Murahata, Yusuke; Ito, Norihiko; Okamoto, Yoshiharu; Minami, Saburo

2015-01-01

Urocanic acid is a major ultraviolet (UV)-absorbing chromophore. Chitins are highly crystalline structures that are found predominantly in crustacean shells. Alpha-chitin consists of microfibers that contain nanofibrils embedded in a protein matrix. Acid hydrolysis is a common method used to prepare chitin nanofibrils (NFs). We typically obtain NFs by hydrolyzing chitin with acetic acid. However, in the present study, we used urocanic acid to prepare urocanic acid chitin NFs (UNFs) and examined its protective effect against UVB radiation. Hos: HR-1 mice coated with UNFs were UVB irradiated (302 nm, 150 mJ/cm2), and these mice showed markedly lower UVB radiation-induced cutaneous erythema than the control. Additionally, sunburn cells were rarely detected in the epidermis of UNFs-coated mice after UVB irradiation. Although the difference was not as significant as UNFs, the number of sunburn cells in mice treated with acetic acid chitin nanofibrils (ANFs) tended to be lower than in control mice. These results demonstrate that ANFs have a protective effect against UVB and suggest that the anti-inflammatory and antioxidant effects of NFs influence the protective effect of ANFs against UVB radiation. The combination of NFs with other substances that possess UV-protective effects, such as urocanic acid, may provide an enhanced protective effect against UVB radiation. PMID:26703629

Chitin degradation and electricity generation by Aeromonas hydrophila in microbial fuel cells.

PubMed

Li, Shan-Wei; He, Hui; Zeng, Raymond J; Sheng, Guo-Ping

2017-02-01

Chitin is one of the most abundant biopolymers in nature and the main composition of shrimp and crab shells (usually as food wastes). Thus it is essential to investigate the potential of degrading chitin for energy recovery. This study investigated the anaerobic degradation of chitin by Aeromonas hydrophila, a chitinolytic and popular electroactive bacterium, in both fermentation and microbial fuel cell (MFC) systems. The primary chitin metabolites produced in MFC were succinate, lactate, acetate, formate, and ethanol. The total metabolite concentration from chitin degradation increased seven-fold in MFC compared to the fermentation system, as well as additional electricity generation. Moreover, A. hydrophila degraded GlcNAc (the intermediate of chitin hydrolysis) significantly faster (0.97 and 0.94 mM C/d/mM-GlcNAc) than chitin (0.13 and 0.03 mM C/d/mM-GlcNAc) in MFC and fermentation systems, indicating that extracellular hydrolysis of chitin was the rate-limiting step and this step could be accelerated in MFC. Furthermore, more chemicals produced by the addition of exogenous mediators in MFC. This study proves that the chitin could be degraded effectively by an electroactive bacterium in MFC, and our results suggest that this bioelectrochemical system might be useful for the degradation of recalcitrant biomass to recover energy. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chitin degradation and utilization by virulent Aeromonas hydrophila strain ML10-51K.

PubMed

Zhang, Dunhua; Xu, De-Hai; Qiu, Junqiang; Rasmussen-Ivey, Cody R; Liles, Mark R; Beck, Benjamin H

2017-05-01

Virulent Aeromonas hydrophila (vAh) is one of the most important bacterial pathogens that causes persistent outbreaks of motile Aeromonas septicemia in warm-water fishes. The survivability of this pathogen in aquatic environments is of great concern. The aim of this study was to determine the capability of the vAh strain ML10-51K to degrade and utilize chitin. Genome-wide analysis revealed that ML10-51K encodes a suite of proteins for chitin metabolism. Assays in vitro showed that four chitinases, one chitobiase and one chitin-binding protein were secreted extracellularly and participated in chitin degradation. ML10-51K was shown to be able to use not only N-acetylglucosamine and colloidal chitin but also chitin flakes as sole carbon sources for growth. This study indicates that ML10-51K is a highly chitinolytic bacterium and suggests that the capability of effective chitin utilization could enable the bacterium to attain high densities when abundant chitin is available in aquatic niches.

Immobilization of Lipase Inhibitor on the Biopolymers from Agaricus bisporus Cell Walls

PubMed Central

2017-01-01

Summary One of the methods for curing obesity is the inclusion of some substances with the antilipase activity in the diet and thus reducing the uptake of fat components from food. The aim of this research is to provide a stabilized form of lipase inhibitor by immobilization of enzyme on the biopolymers from Agaricus bisporus cell walls. The phenolic compounds extracted from the rapeseed were considered as the lipase inhibitor. The activity of the inhibitor was considerably reduced in the gastric juice, as well as at temperatures above 37 °C and during its storage, which determined the suitability of the inhibitor for stabilization on the matrix. The effectiveness of the phenolic compound stabilization was investigated by means of immobilization on the biopolymers from Agaricus bisporus cell wall matrix. The biopolymers used were β-glucan, chitin, melanin and proteins. A number of samples, which differed both in the content of the inhibitor (from 1 to 16%) and in the ratio of biopolymers in the matrix composition, was obtained. The conditions of immobilization (temperature, duration of the process) were also varied. The expediency of obtaining the sample with the inhibitor content of 12% and matrix containing 47.9% of glucan, 18.8% of chitin, 18.8% of melanin and 11.1% of proteins was shown. The best immobilization was carried out at 20–25 °C for 30 min. Thermal analysis and infrared spectroscopy data confirmed that immobilization of the lipase inhibitor on the matrix was due to the hydrogen bonds. The immobilized inhibitor had higher pH stability and higher thermal stability than the original one. The remaining activity of the immobilized inhibitor was higher than the original one after incubation in the gastric acid and bile. The immobilized inhibitor was characterized by a low loss of activity after 12 months of storage. PMID:29540987

Isolation and characterization of chitin and chitosan from marine origin.

PubMed

Nwe, Nitar; Furuike, Tetsuya; Tamura, Hiroshi

2014-01-01

Nowadays, chitin and chitosan are produced from the shells of crabs and shrimps, and bone plate of squid in laboratory to industrial scale. Production of chitosan involved deproteinization, demineralization, and deacetylation. The characteristics of chitin and chitosan mainly depend on production processes and conditions. The characteristics of these biopolymers such as appearance of polymer, turbidity of polymer solution, degree of deacetylation, and molecular weight are of major importance on applications of these polymers. This chapter addresses the production processes and conditions to produce chitin, chitosan, and chito-oligosaccharide and methods for characterization of chitin, chitosan, and chito-oligosaccharide. © 2014 Elsevier Inc. All rights reserved.

SEM characterization of anatomical variation in chitin organization in insect and arthropod cuticles.

PubMed

Chandran, Rakkiyappan; Williams, Lee; Hung, Albert; Nowlin, Kyle; LaJeunesse, Dennis

2016-03-01

The cuticles of insects and arthropods have some of the most diverse material properties observed in nature, so much so that it is difficult to imagine that all cutciles are primarily composed of the same two materials: a fibrous chitin network and a matrix composed of cuticle proteins. Various factors contribute to the mechanical and optical properties of an insect or arthropod cuticle including the thickness and composition. In this paper, we also identified another factor that may contribute to the optical, surface, and mechanical properties of a cuticle, i.e. the organization of chitin nanofibers and chitin fiber bundles. Self-assembled chitin nanofibers serve as the foundation for all higher order chitin structures in the cuticles of insects and other arthropods via interactions with structural cuticle proteins. Using a technique that enables the characterization of chitin organization in the cuticle of intact insects and arthropod exoskeletons, we demonstrate a structure/function correlation of chitin organization with larger scale anatomical structures. The chitin scaffolds in cuticles display an extraordinarily diverse set of morphologies that may reflect specific mechanical or physical properties. After removal of the proteinaceous and mineral matrix of a cuticle, we observe using SEM diverse nanoscale and micro scale organization of in-situ chitin in the wing, head, eye, leg, and dorsal and ventral thoracic regions of the periodical cicada Magicicada septendecim and in other insects and arthropods. The organization of chitin also appears to have a significant role in the organization of nanoscale surface structures. While microscale bristles and hairs have long been known to be chitin based materials formed as cellular extensions, we have found a nanostructured layer of chitin in the cuticle of the wing of the dog day annual cicada Tibicen tibicens, which may be the scaffold for the nanocone arrays found on the wing. We also use this process to examine

Chitin Adsorbents for Toxic Metals: A Review

PubMed Central

Anastopoulos, Ioannis; Bhatnagar, Amit; Bikiaris, Dimitrios N.; Kyzas, George Z.

2017-01-01

Wastewater treatment is still a critical issue all over the world. Among examined methods for the decontamination of wastewaters, adsorption is a promising, cheap, environmentally friendly and efficient procedure. There are various types of adsorbents that have been used to remove different pollutants such as agricultural waste, compost, nanomaterials, algae, etc., Chitin (poly-β-(1,4)-N-acetyl-d-glucosamine) is the second most abundant natural biopolymer and it has attracted scientific attention as an inexpensive adsorbent for toxic metals. This review article provides information about the use of chitin as an adsorbent. A list of chitin adsorbents with maximum adsorption capacity and the best isotherm and kinetic fitting models are provided. Moreover, thermodynamic studies, regeneration studies, the mechanism of adsorption and the experimental conditions are also discussed in depth. PMID:28067848

Chitin enhances biocontrol of Rhodotorula mucilaginosa to postharvest decay of peaches.

PubMed

Zhang, Hongyin; Yang, Qiya; Ge, Lingling; Zhang, Guochao; Zhang, Xiaoli; Zhang, Xiaoyun

2016-07-01

Biological control using microbial antagonists is a promising alternative approach to synthetic fungicides. However, effective biological control requires enhancing the consistency and efficacy of the antagonists used to control postharvest diseases. This study investigated the effect of chitin on the biocontrol efficacy of Rhodotorula mucilaginosa against blue mold and Rhizopus decay of peaches and on the protein expression profiles of R. mucilaginosa. The antagonistic activity of R. mucilaginosa harvested from the nutrient yeast dextrose broth (NYDB) with 0.5% chitin added was significantly improved compared with culture in NYDB without chitin. The R. mucilaginosa population cultured in chitin-supplement NYDB and nutrient yeast chitin borth (NYCB) harvested from peach wounds was more than that of R. mucilaginosa cultured in NYDB without chitin throughout the storage period except at 1 d. The protein expression profiles findings revealed that there were several differentially expressed proteins of R. mucilaginosa in the 0.5% chitin-supplemented NYDB and NYCB compared with that of R. mucilaginosa in NYDB. Most of these were cellular proteomes relating to the primary metabolic reactions such as glycoside hydrolases, phosphoribosyl pyrophosphate, and NADH dehydrogenases. Some proteins were also related to signal transmission and stress response. Copyright © 2016 Elsevier B.V. All rights reserved.

A comparative study of sorption of chromium (III) onto chitin and chitosan

NASA Astrophysics Data System (ADS)

Singh, Pooja; Nagendran, R.

2016-06-01

Heavy metals have always been the most hazardous components in the wastewater of industries like electroplating, automobiles, mining facilities and fertilizer manufacturers. Treatment of heavy metal laden wastewater requires expensive operational and maintenance systems. Food processing industries create a huge amount of shell waste which is sold to poultry farms in powdered form but the quantity thus used is still not comparable to the left over waste. The shell contains chitin which acts as an adsorbent for the heavy metals and can be used to treat heavy metal wastewater. The paper presents a study on the use of chitin and its processed product, chitosan, to remove chromium. Shake flask experiment was conducted to compare the adsorptive capacity of chitin and chitosan for chromium removal from simulated solution and isotherm studies were carried out. The studies showed that the chitosan was a better adsorbent than chitin. Both chitin and chitosan gave best adsorption results at pH 3. Chitin exhibited maximum chromium removal of 49.98 % in 20 min, whereas chitosan showed 50 % removal efficiency at a contact time of 20 min showing higher adsorptive capacity for chromium than chitin. The Langmiur and Freundlich isotherm studies showed very good adsorption capacity and monolayer interaction according to the regression coefficient 0.973 for chitosan and 0.915 for chitin. The regression coefficient for Freundlich isotherm was 0.894 and 0.831 for chitosan and chitin, respectively.

In situ chitin isolation from body parts of a centipede and lysozyme adsorption studies.

PubMed

Bulut, Esra; Sargin, Idris; Arslan, Ozlem; Odabasi, Mehmet; Akyuz, Bahar; Kaya, Murat

2017-01-01

Isolation of structurally intact chitin samples for biotechnological applications has gained much recent attention. So far, three-dimensional chitin isolates have been obtained from only diplopods and sponges. In this study, three-dimensional chitin isolates were obtained from the body parts of centipede Scolopendra sp. (antennae, head, forcipule, collum, trunk, trunk legs and last pair of legs) without leading to structural failure. FT-IR spectra of chitin isolates confirmed that chitin samples are in α allomorph. TGA, XRD and SEM analyses and lysozyme adsorption studies revealed that each chitin isolate had different thermal stability, crystallinity and surface characteristics. Among the chitin isolates, Cu(II)-immobilized forcipule chitin showed the highest affinity for lysozyme (54.1mg/g), whereas chitin from last pair of legs exhibited the lowest affinity (3.7mg/g). This study demonstrated that structurally intact chitin isolates can be obtained from the body parts of centipede Scolopendra sp. (antennae, head, forcipule, collum, trunk, trunk legs and last pair of legs) by using a simple chemical procedure. Also, it gives a biotechnological perspective to the organisms in the group of Chilipoda. Copyright © 2016 Elsevier B.V. All rights reserved.

Heterologous expression of an active chitin synthase from Rhizopus oryzae.

PubMed

Salgado-Lugo, Holjes; Sánchez-Arreguín, Alejandro; Ruiz-Herrera, José

2016-12-01

Chitin synthases are highly important enzymes in nature, where they synthesize structural components in species belonging to different eukaryotic kingdoms, including kingdom Fungi. Unfortunately, their structure and the molecular mechanism of synthesis of their microfibrilar product remain largely unknown, probably because no fungal active chitin synthases have been isolated, possibly due to their extreme hydrophobicity. In this study we have turned to the heterologous expression of the transcript from a small chitin synthase of Rhizopus oryzae (RO3G_00942, Chs1) in Escherichia coli. The enzyme was active, but accumulated mostly in inclusion bodies. High concentrations of arginine or urea solubilized the enzyme, but their dilution led to its denaturation and precipitation. Nevertheless, use of urea permitted the purification of small amounts of the enzyme. The properties of Chs1 (Km, optimum temperature and pH, effect of GlcNAc) were abnormal, probably because it lacks the hydrophobic transmembrane regions characteristic of chitin synthases. The product of the enzyme showed that, contrasting with chitin made by membrane-bound Chs's and chitosomes, was only partially in the form of short microfibrils of low crystallinity. This approach may lead to future developments to obtain active chitin synthases that permit understanding their molecular mechanism of activity, and microfibril assembly. Copyright © 2016. Published by Elsevier Inc.

Transmembrane myosin chitin synthase involved in mollusc shell formation produced in Dictyostelium is active

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schoenitzer, Veronika; Universitaet Regensburg, Biochemie I, Universitaetsstrasse 31, D-93053 Regensburg; Eichner, Norbert

Highlights: Black-Right-Pointing-Pointer Dictyostelium produces the 264 kDa myosin chitin synthase of bivalve mollusc Atrina. Black-Right-Pointing-Pointer Chitin synthase activity releases chitin, partly associated with the cell surface. Black-Right-Pointing-Pointer Membrane extracts of transgenic slime molds produce radiolabeled chitin in vitro. Black-Right-Pointing-Pointer Chitin producing Dictyostelium cells can be characterized by atomic force microscopy. Black-Right-Pointing-Pointer This model system enables us to study initial processes of chitin biomineralization. -- Abstract: Several mollusc shells contain chitin, which is formed by a transmembrane myosin motor enzyme. This protein could be involved in sensing mechanical and structural changes of the forming, mineralizing extracellular matrix. Here we report themore » heterologous expression of the transmembrane myosin chitin synthase Ar-CS1 of the bivalve mollusc Atrina rigida (2286 amino acid residues, M.W. 264 kDa/monomer) in Dictyostelium discoideum, a model organism for myosin motor proteins. Confocal laser scanning immunofluorescence microscopy (CLSM), chitin binding GFP detection of chitin on cells and released to the cell culture medium, and a radiochemical activity assay of membrane extracts revealed expression and enzymatic activity of the mollusc chitin synthase in transgenic slime mold cells. First high-resolution atomic force microscopy (AFM) images of Ar-CS1 transformed cellulose synthase deficient D. discoideumdcsA{sup -} cell lines are shown.« less

Customizing Properties of β-Chitin in Squid Pen (Gladius) by Chemical Treatments

PubMed Central

Ianiro, Alessandro; Di Giosia, Matteo; Fermani, Simona; Samorì, Chiara; Barbalinardo, Marianna; Valle, Francesco; Pellegrini, Graziella; Biscarini, Fabio; Zerbetto, Francesco; Calvaresi, Matteo; Falini, Giuseppe

2014-01-01

The squid pen (gladius) from the Loligo vulgaris was used for preparation of β-chitin materials characterized by different chemical, micro- and nano-structural properties that preserved, almost completely the macrostructural and the mechanical ones. The β-chitin materials obtained by alkaline treatment showed porosity, wettability and swelling that are a function of the duration of the treatment. Microscopic, spectroscopic and synchrotron X-ray diffraction techniques showed that the chemical environment of the N-acetyl groups of the β-chitin chains changes after the thermal alkaline treatment. As a consequence, the crystalline packing of the β-chitin is modified, due to the intercalation of water molecules between β-chitin sheets. Potential applications of these β-chitin materials range from the nanotechnology to the regenerative medicine. The use of gladii, which are waste products of the fishing industry, has also important environmental implications. PMID:25517216

A protocol for the simultaneous identification of chitin-containing particles and their associated bacteria.

PubMed

Biancalana, Florencia; Kopprio, Germán A; Lara, Rubén J; Alonso, Cecilia

2017-07-01

Chitin is the second most abundant polymer on Earth, playing a crucial role in the biogeochemical cycles. A core issue for studying its processing in aquatic systems is the identification and enumeration of chitin-containing particles and organisms, ideally in a manner that can be directly linked to bulk chitin quantification. The aim of this study was the development of such a technique. We successfully combined the methodology of bulk chitin determination using wheat germ agglutinin (FITC-WGA) for staining chitin-containing particles and organisms along with CARD-FISH staining of either chitin-containing eukaryotic cells or bacteria associated with them. Environmental chitin staining was successfully applied to natural water samples. Fungal hyphae, diatoms, and dinoflagellates, sestonic aggregates and chitin-containing structures derived from metazoa were observed. Also, hybridized bacteria attached to chitinaceous debris were clearly visualized. Finally, as proof of principle, cultured yeast cells were simultaneously-targeted by FITC-WGA and the EUK516 probe without exhibiting any interference between both stains. The presented approach appears as a powerful tool to evaluate the contribution of different size classes and organisms to chitin production and consumption, opening the possibility for application of single-cell approaches targeting the ecophysiology of chitin transformations in aquatic systems. Copyright © 2017 Elsevier GmbH. All rights reserved.

Bacterial chitinolytic communities respond to chitin and pH alteration in soil.

PubMed

Kielak, Anna M; Cretoiu, Mariana Silvia; Semenov, Alexander V; Sørensen, Søren J; van Elsas, Jan Dirk

2013-01-01

Chitin amendment is a promising soil management strategy that may enhance the suppressiveness of soil toward plant pathogens. However, we understand very little of the effects of added chitin, including the putative successions that take place in the degradative process. We performed an experiment in moderately acid soil in which the level of chitin, next to the pH, was altered. Examination of chitinase activities revealed fast responses to the added crude chitin, with peaks of enzymatic activity occurring on day 7. PCR-denaturing gradient gel electrophoresis (DGGE)-based analyses of 16S rRNA and chiA genes showed structural changes of the phylogenetically and functionally based bacterial communities following chitin addition and pH alteration. Pyrosequencing analysis indicated (i) that the diversity of chiA gene types in soil is enormous and (i) that different chiA gene types are selected by the addition of chitin at different prevailing soil pH values. Interestingly, a major role of Gram-negative bacteria versus a minor one of Actinobacteria in the immediate response to the added chitin (based on 16S rRNA gene abundance and chiA gene types) was indicated. The results of this study enhance our understanding of the response of the soil bacterial communities to chitin and are of use for both the understanding of soil suppressiveness and the possible mining of soil for novel enzymes.

Morphological and thermal studies of chitin-curcumin blends derived polyurethanes.

PubMed

Mahmood, Kashif; Zia, Khalid Mahmood; Zuber, Mohammad; Tabasum, Shazia; Rehman, Saima; Zia, Fatima; Noreen, Aqdas

2017-12-01

The present study describes a novel ecofriendly series of chitin/curcumin/1,4-butane diol (BDO) blend derived polyurethanes (PUs), using hydroxy terminated polybutadiene (HTPB) and hexamethylene diisocyanate (HDI) along with different mole ratio of chitin, curcumin and BDO. The structural and morphological elucidation of the prepared films was done by FTIR and SEM techniques. The swelling behavior of the films was analyzed in both water and DMSO, which showed that incorporation of chitin increases the hydrophobicity and decreases the rate of swelling. Thermal analysis of synthesized PU blends revealed better thermal stability with following mole ratio 1:0.5:0.5 of chitin: curcumin: BDO as determined by TGA and DSC techniques. Copyright © 2017 Elsevier B.V. All rights reserved.

Three-dimensional (3D) structure prediction and function analysis of the chitin-binding domain 3 protein HD73_3189 from Bacillus thuringiensis HD73.

PubMed

Zhan, Yiling; Guo, Shuyuan

2015-01-01

Bacillus thuringiensis (Bt) is capable of producing a chitin-binding protein believed to be functionally important to bacteria during the stationary phase of its growth cycle. In this paper, the chitin-binding domain 3 protein HD73_3189 from B. thuringiensis has been analyzed by computer technology. Primary and secondary structural analyses demonstrated that HD73_3189 is negatively charged and contains several α-helices, aperiodical coils and β-strands. Domain and motif analyses revealed that HD73_3189 contains a signal peptide, an N-terminal chitin binding 3 domains, two copies of a fibronectin-like domain 3 and a C-terminal carbohydrate binding domain classified as CBM_5_12. Moreover, analysis predicted the protein's associated localization site to be the cell wall. Ligand site prediction determined that amino acid residues GLU-312, TRP-334, ILE-341 and VAL-382 exposed on the surface of the target protein exhibit polar interactions with the substrate.

Chitin and Chitosan as Direct Compression Excipients in Pharmaceutical Applications

PubMed Central

Badwan, Adnan A.; Rashid, Iyad; Al Omari, Mahmoud M.H.; Darras, Fouad H.

2015-01-01

Despite the numerous uses of chitin and chitosan as new functional materials of high potential in various fields, they are still behind several directly compressible excipients already dominating pharmaceutical applications. There are, however, new attempts to exploit chitin and chitosan in co-processing techniques that provide a product with potential to act as a direct compression (DC) excipient. This review outlines the compression properties of chitin and chitosan in the context of DC pharmaceutical applications. PMID:25810109

Physicochemical and antifungal properties of bio-nanocomposite film based on gelatin-chitin nanoparticles.

PubMed

Sahraee, Samar; Milani, Jafar M; Ghanbarzadeh, Babak; Hamishehkar, Hamed

2017-04-01

The gelatin-based nanocomposite films containing chitin nanoparticles (N-chitin) with concentrations of 0, 3, 5 and 10% were prepared and their physical, thermal and anti-microbial properties were investigated. Scanning electron microscopy (SEM) micrographs showed that N-chitin size distribution was around 60-70nm which dispersed appropriately at low concentration in gelatin matrix. The results showed that incorporation of N-chitin significantly influenced apparent color and transparency of the gelatin films. The reduced water vapor permeability (WVP) and solubility and higher surface hydrophobicity of the nanocomposite films were obtained by enhancing N-chitin concentration in film formulation. The use of N-chitin up to 5% concentration in the gelatin based nanocomposite film led to improved mechanical properties. Also, the results of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) confirmed improved stability of nanocomposite films against melting and degradation at high temperatures in comparison to neat gelatin film. The well compatibility of chitin nanoparticles with gelatin polymer was concluded from Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD) plots. Finally, the gelatin based nanocomposite films had anti-fungal properties against Aspergillus niger in the contact surface zone. Increasing the concentration of N-chitin up to 5% enlarged inhibition zone diameter, but the nanocomposite film containing 10% N-chitin showed smaller inhibition zone. Copyright © 2016 Elsevier B.V. All rights reserved.

Microbial responses to chitin and chitosan in oxic and anoxic agricultural soil slurries

NASA Astrophysics Data System (ADS)

Wieczorek, A. S.; Hetz, S. A.; Kolb, S.

2014-06-01

Microbial degradation of chitin in soil substantially contributes to carbon cycling in terrestrial ecosystems. Chitin is globally the second most abundant biopolymer after cellulose and can be deacetylated to chitosan or can be hydrolyzed to N,N'-diacetylchitobiose and oligomers of N-acetylglucosamine by aerobic and anaerobic microorganisms. Which pathway of chitin hydrolysis is preferred by soil microbial communities is unknown. Supplementation of chitin stimulated microbial activity under oxic and anoxic conditions in agricultural soil slurries, whereas chitosan had no effect. Thus, the soil microbial community likely was more adapted to chitin as a substrate. In addition, this finding suggested that direct hydrolysis of chitin was preferred to the pathway that starts with deacetylation. Chitin was apparently degraded by aerobic respiration, ammonification, and nitrification to carbon dioxide and nitrate under oxic conditions. When oxygen was absent, fermentation products (acetate, butyrate, propionate, hydrogen, and carbon dioxide) and ammonia were detected, suggesting that butyric and propionic acid fermentation, along with ammonification, were likely responsible for anaerobic chitin degradation. In total, 42 different chiA genotypes were detected of which twenty were novel at an amino acid sequence dissimilarity of less than 50%. Various chiA genotypes responded to chitin supplementation and affiliated with a novel deep-branching bacterial chiA genotype (anoxic conditions), genotypes of Beta- and Gammaproteobacteria (oxic and anoxic conditions), and Planctomycetes (oxic conditions). Thus, this study provides evidence that detected chitinolytic bacteria were catabolically diverse and occupied different ecological niches with regard to oxygen availability enabling chitin degradation under various redox conditions on community level.

Microbial responses to chitin and chitosan in oxic and anoxic agricultural soil slurries

NASA Astrophysics Data System (ADS)

Wieczorek, A. S.; Hetz, S. A.; Kolb, S.

2014-02-01

Chitin is the second most abundant biopolymer in terrestrial ecosystems and is subject to microbial degradation. Chitin can be deacetylated to chitosan or can be hydrolyzed to N,N'-diacetylchitobiose and oligomers of N-acetylglucosamine by aerobic and anaerobic microorganisms. Which pathway of chitin hydrolysis is preferred by soil microbial communities has previously been unknown. Supplementation of chitin stimulated microbial activity under oxic and anoxic conditions in agricultural soil slurries, whereas chitosan had no effect. Thus, the soil microbial community likely was more adapted to chitin as a substrate. In addition, this finding suggested that direct hydrolysis of chitin was preferred to the pathway that starts with deacetylation. Chitin was apparently degraded by aerobic respiration, ammonification, and nitrification to carbon dioxide and nitrate under oxic conditions. When oxygen was absent, fermentation products (acetate, butyrate, propionate, hydrogen, carbon dioxide) and ammonia were detected, suggesting that butyric and propionic acid fermentation were along with ammonification likely responsible for apparent anaerobic chitin degradation. In total, 42 different chiA genotypes were detected of which twenty were novel at an amino acid sequence dissimilarity of >50%. Various chiA genotypes responded to chitin supplementation and affiliated with a novel deep-branching bacterial chiA genotype (anoxic conditions), genotypes of Beta- and Gammaproteobacteria (oxic and anoxic conditions), and Planctomycetes (oxic conditions). Thus, this study provides evidence that detected chitinolytic bacteria were catabolically diverse and occupied different ecological niches with regard to oxygen availability enabling chitin degradation under various redox conditions at the level of the community.

The first report of the physicochemical structure of chitin isolated from Hermetia illucens.

PubMed

Waśko, Adam; Bulak, Piotr; Polak-Berecka, Magdalena; Nowak, Katarzyna; Polakowski, Cezary; Bieganowski, Andrzej

2016-11-01

This is the first report on the physicochemical properties of chitin obtained from larvae and imagoes of black soldier flies (Hermetia illucens). Scanning electron microscopy revealed differences in surface morphologies of the two types of chitin. The crystalline index values of chitins from adult flies and larvae were 24.9% and 35%, respectively. This is a trait that differentiates these biopolymers from chitins extracted from other sources described so far. X-ray diffraction patterns and IR spectroscopy revealed that both types of samples of chitin were in an α crystalline form. Also, the results of elemental analysis, thermal stabilities and FTIR spectroscopy of the chitins from larvae and adults of H. illucens were similar, which points to a general similarity in their physicochemical structure. Copyright © 2016 Elsevier B.V. All rights reserved.

Regulation of Neurospora crassa cell wall remodeling via the cot-1 pathway is mediated by gul-1.

PubMed

Herold, Inbal; Yarden, Oded

2017-02-01

Impairment of the Neurospora crassa Nuclear DBF2-related kinase-encoding gene cot-1 results in pleiotropic effects, including abnormally thick hyphal cell walls and septa. An increase in the transcript abundance of genes encoding chitin and glucan synthases and the chitinase gh18-5, but not the cell wall integrity pathway transcription factor rlm-1, accompany the phenotypic changes observed. Deletion of chs-5 or chs-7 in a cot-1 background results in a reduction of hyperbranching frequency characteristic of the cot-1 parent. gul-1 (a homologue of the yeast SSD1 gene) encodes a translational regulator and has been shown to partially suppress cot-1. We demonstrate that the high expression levels of the cell wall remodeling genes analyzed is curbed, and reaches near wild type levels, when gul-1 is inactivated. This is accompanied by morphological changes that include reduced cell wall thickness and restoration of normal chitin levels. We conclude that gul-1 is a mediator of cell wall remodeling within the cot-1 pathway.

Facile nanofibrillation of chitin derivatives by gas bubbling and ultrasonic treatments in water.

PubMed

Tanaka, Kohei; Yamamoto, Kazuya; Kadokawa, Jun-ichi

2014-10-29

In this paper, we report that nanofiber network structures were constructed from chitin derivatives by gas bubbling and ultrasonic treatments in water. When chitin was first subjected to N2 gas bubbling with ultrasonication in water, the SEM images of the product showed nanofiber network morphology. However, nanofiber network was not re-constructed by the same N2 gas bubbling and ultrasonic treatments after agglomeration. We then have paid attention to an amidine group to provide the agglomeration-nanofibrillation behavior of chitin derivatives. An amidinated chitin was synthesized by the reaction of the amino groups in a partially deacetylated chitin with N,N-dimethylacetamide dimethyl acetal, which was subjected to CO2 gas bubbling and ultrasonic treatments in water to convert into an amidinium chitin by protonation. The SEM images of the product clearly showed nanofiber network morphology. We further examined re-nanofibrillation of the agglomerated material, which was obtained by mixing the nanofibrillated amidinium chitin with water, followed by drying under reduced pressure. Consequently, the material was re-nanofibrillated by N2 gas bubbling with ultrasonication in water owing to electrostatic repulsion between the amidinium groups. Furthermore, deprotonation of the amidinium chitin and re-protonation of the resulting amidinated chitin were conducted by alkaline treatment and CO2 gas bubbling-ultrasonic treatments, respectively. The material showed the agglomeration-nanofibrillation behavior during the processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Recent trends in biological extraction of chitin from marine shell wastes: a review.

PubMed

Kaur, Surinder; Dhillon, Gurpreet Singh

2015-03-01

The natural biopolymer chitin and its deacetylated product chitosan are widely used in innumerable applications ranging from biomedicine, pharmaceuticals, food, agriculture and personal care products to environmental sector. The abundant and renewable marine processing wastes are commercially exploited for the extraction of chitin. However, the traditional chitin extraction processes employ harsh chemicals at elevated temperatures for a prolonged time which can harm its physico-chemical properties and are also held responsible for the deterioration of environmental health. In view of this, green extraction methods are increasingly gaining popularity due to their environmentally friendly nature. The bioextraction of chitin from crustacean shell wastes has been increasingly researched at the laboratory scale. However, the bioextraction of chitin is not currently exploited to its maximum potential on the commercial level. Bioextraction of chitin is emerging as a green, cleaner, eco-friendly and economical process. Specifically in the chitin extraction, microorganisms-mediated fermentation processes are highly desirable due to easy handling, simplicity, rapidity, controllability through optimization of process parameters, ambient temperature and negligible solvent consumption, thus reducing environmental impact and costs. Although, chitin production from crustacean shell waste through biological means is still at its early stage of development, it is undergoing rapid progress in recent years and showing a promising prospect. Driven by reduced energy, wastewater or solvent, advances in biological extraction of chitin along with valuable by-products will have high economic and environmental impact.

Surface modification of chitin and chitosan with poly(3-hexylthiophene) via oxidative polymerization

NASA Astrophysics Data System (ADS)

Hai, Thien An Phung; Sugimoto, Ryuichi

2018-03-01

In the present work, the modification of biomaterials such as chitin and chitosan were successfully prepared by directly grafting poly(3-hexylthiophene) (P3HT) to their surfaces using simple oxidative polymerization with FeCl3. The thermal stability and crystallinity of grafted chitin and chitosan changed upon grafting with P3HT. The build-up of π-π* structure from the P3HT on the surface of chitin and chitosan resulted in the appearance of UV-vis absorption and fluorescence emission peaks in the range from 500 to 600 nm. Introducing P3HT to the surface of chitin and chitosan improved significantly the electrical property of chitin and chitosan with the increase in conductivity from 10-9 to 10-7 S/cm. Furthermore, the usual behavior of hydrophilic surface of chitin and chitosan that turned to hydrophobic with water contact angle of 97.7° and 107.0°, respectively in the presence of P3HT. The mechanism for graft reaction of P3HT to chitin and chitosan was also proposed and discussed.

Bacterial Chitin Hydrolysis in Two Lakes with Contrasting Trophic Statuses

PubMed Central

Carstens, Dörte; Keller, Esther; Vazquez, Francisco; Schubert, Carsten J.; Zeyer, Josef; Bürgmann, Helmut

2012-01-01

Chitin, which is a biopolymer of the amino sugar glucosamine (GlcN), is highly abundant in aquatic ecosystems, and its degradation is assigned a key role in the recycling of carbon and nitrogen. In order to study the significance of chitin decomposition in two temperate freshwater lakes with contrasting trophic and redox conditions, we measured the turnover rate of the chitin analog methylumbelliferyl-N,N′-diacetylchitobioside (MUF-DC) and the presence of chitinase (chiA) genes in zooplankton, water, and sediment samples. In contrast to the eutrophic and partially anoxic lake, chiA gene fragments were detectable throughout the oligotrophic water column and chiA copy numbers per ml of water were up to 15 times higher than in the eutrophic waters. For both lakes, the highest chiA abundance was found in the euphotic zone—the main habitat of zooplankton, but also the site of production of easily degradable algal chitin. The bulk of chitinase activity was measured in zooplankton samples and the sediments, where recalcitrant chitin is deposited. Both, chiA abundance and chitinase activity correlated well with organic carbon, nitrogen, and concentrations of particulate GlcN. Our findings show that chitin, although its overall contribution to the total organic carbon is small (∼0.01 to 0.1%), constitutes an important microbial growth substrate in these temperate freshwater lakes, particularly where other easily degradable carbon sources are scarce. PMID:22101058

Interaction of chitin/chitosan with salivary and other epithelial cells-An overview.

PubMed

Patil, Sharvari Vijaykumar; Nanduri, Lalitha S Y

2017-11-01

Chitin and its deacetylated form, chitosan, have been widely used for tissue engineering of both epithelial and mesenchymal tissues. Epithelial cells characterised by their sheet-like tight cellular arrangement and polarised nature, constitute a major component in various organs and play a variety of roles including protection, secretion and maintenance of tissue homeostasis. Regeneration of damaged epithelial tissues has been studied using biomaterials such as chitin, chitosan, hyaluronan, gelatin and alginate. Chitin and chitosan are known to promote proliferation of various embryonic and adult epithelial cells. However it is not clearly understood how this activity is achieved or what are the mechanisms involved in the chitin/chitosan driven proliferation of epithelial cells. Mechanistic understanding of influence of chitin/chitosan on epithelial cells will guide us to develop more targeted regenerative scaffold/hydrogel systems. Therefore, current review attempts to elicit a mechanistic insight into how chitin and chitosan interact with salivary, mammary, skin, nasal, lung, intestinal and bladder epithelial cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Distinct roles of cell wall biogenesis in yeast morphogenesis as revealed by multivariate analysis of high-dimensional morphometric data

PubMed Central

Okada, Hiroki; Ohnuki, Shinsuke; Roncero, Cesar; Konopka, James B.; Ohya, Yoshikazu

2014-01-01

The cell wall of budding yeast is a rigid structure composed of multiple components. To thoroughly understand its involvement in morphogenesis, we used the image analysis software CalMorph to quantitatively analyze cell morphology after treatment with drugs that inhibit different processes during cell wall synthesis. Cells treated with cell wall–affecting drugs exhibited broader necks and increased morphological variation. Tunicamycin, which inhibits the initial step of N-glycosylation of cell wall mannoproteins, induced morphologies similar to those of strains defective in α-mannosylation. The chitin synthase inhibitor nikkomycin Z induced morphological changes similar to those of mutants defective in chitin transglycosylase, possibly due to the critical role of chitin in anchoring the β-glucan network. To define the mode of action of echinocandin B, a 1,3-β-glucan synthase inhibitor, we compared the morphology it induced with mutants of Fks1 that contains the catalytic domain for 1,3-β-glucan synthesis. Echinocandin B exerted morphological effects similar to those observed in some fks1 mutants, with defects in cell polarity and reduced glucan synthesis activity, suggesting that echinocandin B affects not only 1,3-β-glucan synthesis, but also another functional domain. Thus our multivariate analyses reveal discrete functions of cell wall components and increase our understanding of the pharmacology of antifungal drugs. PMID:24258022

Chitin-Induced Airway Epithelial Cell Innate Immune Responses Are Inhibited by Carvacrol/Thymol

PubMed Central

Erle, David J.

2016-01-01

Chitin is produced in large amounts by fungi, insects, and other organisms and has been implicated in the pathogenesis of asthma. Airway epithelial cells are in direct contact with environmental particles and serve as the first line of defense against inhaled allergens and pathogens. The potential contributions of airway epithelial cells to chitin-induced asthma remain poorly understood. We hypothesized that chitin directly stimulates airway epithelial cells to release cytokines that promote type 2 immune responses and to induce expression of molecules which are important in innate immune responses. We found that chitin exposure rapidly induced the expression of three key type 2-promoting cytokines, IL-25, IL-33 and TSLP, in BEAS-2B transformed human bronchial epithelial cells and in A549 and H292 lung carcinoma cells. Chitin also induced the expression of the key pattern recognition receptors TLR2 and TLR4. Chitin induced the expression of miR-155, miR-146a and miR-21, each of which is known to up-regulate the expression of pro-inflammatory cytokines. Also the expression of SOCS1 and SHIP1 which are known targets of miR-155 was repressed by chitin treatment. The monoterpene phenol carvacrol (Car) and its isomer thymol (Thy) are found in herbal essential oils and have been shown to inhibit allergic inflammation in asthma models. We found that Car/Thy inhibited the effects of chitin on type 2-promoting cytokine release and on the expression of TLRs, SOCS1, SHIP1, and miRNAs. Car/Thy could also efficiently reduce the protein levels of TLR4, inhibit the increase in TLR2 protein levels in chitin plus Car/Thy-treated cells and increase the protein levels of SHIP1 and SOCS1, which are negative regulators of TLR-mediated inflammatory responses. We conclude that direct effects of chitin on airway epithelial cells are likely to contribute to allergic airway diseases like asthma, and that Car/Thy directly inhibits epithelial cell pro-inflammatory responses to chitin. PMID

Chitin: Formation of Helically Structured Chitin/CaCO3 Hybrids through an Approach Inspired by the Biomineralization Processes of Crustacean Cuticles (Small 38/2015).

PubMed

Matsumura, Shunichi; Kajiyama, Satoshi; Nishimura, Tatsuya; Kato, Takashi

2015-10-01

Biomineral-inspired hybrids forming helically ordered structures are developed by T. Kato and co-workers on page 5127. These helical hybrids consist of liquid-crystalline chitin and CaCO3 . They resemble the structures of crustacean cuticles such as the exoskeleton of a lobster or crayfish. These hybrids are formed through CaCO3 crystallization on the liquidcrystalline chitin templates. Polymer-stabilized amorphous CaCO3 is incorporated into the liquid-crystalline chitin templates. This approach is useful for the development of new hierarchical hybrid materials from abundant natural resources. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ChtVis-Tomato, a genetic reporter for in vivo visualization of chitin deposition in Drosophila

PubMed Central

Sobala, Lukasz F.; Wang, Ying; Adler, Paul N.

2015-01-01

Chitin is a polymer of N-acetylglucosamine that is abundant and widely found in the biological world. It is an important constituent of the cuticular exoskeleton that plays a key role in the insect life cycle. To date, the study of chitin deposition during cuticle formation has been limited by the lack of a method to detect it in living organisms. To overcome this limitation, we have developed ChtVis-Tomato, an in vivo reporter for chitin in Drosophila. ChtVis-Tomato encodes a fusion protein that contains an apical secretion signal, a chitin-binding domain (CBD), a fluorescent protein and a cleavage site to release it from the plasma membrane. The chitin reporter allowed us to study chitin deposition in time lapse experiments and by using it we have identified unexpected deposits of chitin fibers in Drosophila pupae. ChtVis-Tomato should facilitate future studies on chitin in Drosophila and other insects. PMID:26395478

Hierarchical Microspheres Constructed from Chitin Nanofibers Penetrated Hydroxyapatite Crystals for Bone Regeneration.

PubMed

Duan, Bo; Shou, Kangquan; Su, Xiaojuan; Niu, Yahui; Zheng, Guan; Huang, Yao; Yu, Aixi; Zhang, Yu; Xia, Hong; Zhang, Lina

2017-07-10

Chitin exists abundantly in crab and shrimp shells as the template of the minerals, which inspired us to mineralize it for fabricating bone grafting materials. In the present work, chitin nanofibrous microspheres were used as the matrix for in situ synthesis of hydroxyapatite (HA) crystals including microflakes, submicron-needles, and submicron-spheres, which were penetrated by long chitin nanofibers, leading to the hierarchical structure. The shape and size of the HA crystals could be controlled by changing the HA synthesis process. The tight interface adhesion between chitin and HA through the noncovanlent bonds occurred in the composite microspheres, and HAs were homogeneously dispersed and bounded to the chitin nanofibers. In our findings, the inherent biocompatibilities of the both chitin and HA contributed the bone cell adhesion and osteoconduction. Moreover, the chitin microsphere with submicron-needle and submicron-sphere HA crystals remarkably promoted in vitro cell adhesion and in vivo bone healing. It was demonstrated that rabbits with 1.5 cm radius defect were almost cured completely within three months in a growth factor- and cell-free state, as a result of the unique surface microstructure and biocompatibilities of the composite microspheres. The microsphere scaffold displayed excellent biofunctions and an appropriate biodegradability. This work opened up a new avenue to construct natural polymer-based organic-inorganic hybrid microspheres for bone regeneration.

Conservation of Chitin-Induced MAPK Signaling Pathways in Rice and Arabidopsis.

PubMed

Yamada, Kenta; Yamaguchi, Koji; Yoshimura, Satomi; Terauchi, Akira; Kawasaki, Tsutomu

2017-06-01

Perception of microbe-associated molecular patterns (MAMPs) including chitin by pattern recognition receptors (PRRs) rapidly induces activation of mitogen-activated protein kinase (MAPK) cascades. However, how PRRs transmit immune signals to the MAPK cascade is largely unknown. Recently, Arabidopsis receptor-like cytoplasmic kinase PBL27 has been reported to activate MAPKs through phosphorylation of AtMAPKKK5 in the chitin signaling pathway. In this study, we found that OsRLCK185, a rice ortholog of PBL27, regulates chitin-induced MAPK activation in a similar fashion to PBL27 in rice. Upon chitin perception, OsRLCK185 is phosphorylated by OsCERK1, a component of the chitin receptor complex. OsRLCK185 interacted with OsMAPKKK11 and OsMAPKKK18, rice orthologs of AtMAPKKK5, in yeast two-hybrid assays. Silencing of both OsMAPKKK11 and OsMAPKKK18 significantly reduced chitin-induced activation of OsMPK3 and OsMPK6. Expression levels of OsMAPKKK18 were much higher than that of OsMAPKKK11 in rice cells, which was consistent with the fact that the Osmapkkk11 single mutation did not affect MAPK activation. This result suggested that OsMAPKKK18 plays a more important role than OsMAPKKK11 in the chitin-induced activation of OsMPK3 and OsMPK6. The bimolecular fluorescence complementation (BiFC) experiment indicated that OsRLCK185 interacted with OsMAPKKK18 at the plasma membrane in planta. In vitro phosphorylation experiments showed that OsRLCK185 directly phosphorylates OsMAPKKK18. Furthermore, OsMAPKKK18 interacted with the MAPKK OsMKK4, the upstream component of OsMPK3/6. These results suggested that OsRLCK185 connects the chitin receptor to the MAPK cascade consisting of OsMAPKKK18-OsMKK4-OsMPK3/6. Our data revealed that chitin-induced MAPK activation in rice and Arabidopsis is regulated by common homologous elements. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please

Cloning and expression of two chitin deacetylase genes of Saccharomyces cerevisiae.

PubMed

Mishra, C; Semino, C E; McCreath, K J; de la Vega, H; Jones, B J; Specht, C A; Robbins, P W

1997-03-30

Chitin deacetylase (EC 3.5.1.41), which hydrolyses the N-acetamido groups of N-acetyl-D-glucosamine residues in chitin, has been demonstrated in crude extracts from sporulating Saccharomyces cerevisiae. Two S. cerevisiae open reading frames (ORFs), identified by the Yeast Genome Project, have protein sequence homology to a chitin deacetylase from Mucor rouxii. Northern blot hybridizations show each ORF was transcribed in diploid cells after transfer to sporulation medium and prior to formation of asci. Each ORF was cloned in a vector under transcriptional control of the GAL 1, 10 promoter and introduced back into haploid strains of S. cerevisiae. Chitin deacetylase activity was detected by in vitro assays from vegetative cells grown in galactose. Chemical analysis of these cells also demonstrated the synthesis of chitosam in vivo. Both recombinant chitin deacetylases showed similar qualitative and quantitative activities toward chitooligosaccharides in vitro. A diploid strain deleted to both ORFs, when sporulated, did not show deacetylase activity. The mutant spores were hypersensitive to lytic enzymes (Glusulase or Zymolyase).

Value-added organonitrogen chemicals evolution from the pyrolysis of chitin and chitosan.

PubMed

Liu, Chao; Zhang, Huiyan; Xiao, Rui; Wu, Shubin

2017-01-20

Thermogravimetric characteristics of chitin and chitosan and their potentials to produce value-added organonitrogen chemicals were separately evaluated via TG/DSC-FTIR and Py-GC/MS. Results shown that chitin had the better thermal stability and higher activation energy than chitosan because of the abundant acetamido group. Furthermore, the dominated volatilization in active pyrolysis of chitin contributed to its endothermic property, whereas the charring in chitosan led to the exothermal. During fast pyrolysis, the acetamido group in chitin and chitosan was converted into acetic acid or acetamide. Typical products from chitosan pyrolysis were aza-heterocyclic chemicals, i.e. pyridines, pyrazines, and pyrroles, with the total selectivity of 50.50% at 600°C. Herein, selectivity of pyrazine compounds was up to 22.99%. These aza-heterocyclic chemicals came from the nucleophilic addition reaction of primary amine and carbonyl. However, main reaction during chitin pyrolysis was ring-opening degradation, which led to the formation of acetamido chemicals, especially acetamido acetaldehyde with the highest selectivity of 27.27% at 450°C. In summary, chitosan had the potential to produce aza-heterocyclic chemicals, and chitin to acetamido chemicals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Immunotherapeutic effects of chitin in comparison with chitosan against Leishmania major infection.

PubMed

Hoseini, Mostafa Haji Molla; Moradi, Maryam; Alimohammadian, Mohammad Hossein; Shahgoli, Vahid Khaze; Darabi, Hayedeh; Rostami, Ali

2016-04-01

Chitin and chitosan microparticles (MPs) are important immune system stimulators. The aim of this study was to evaluate the protective effects of these compounds in comparison with each other against Leishmania infection in BALB/c mice infected with Leishmania major (L. major). Female BALB/c mice were injected subcutaneously with 2×10(5) promastigotes. Chitin and/or chitosan MPs (<40 μm) were subcutaneously injected in the BALB/c mice with two-day intervals until two weeks. Mice in all groups were sacrificed at 12 weeks post-infection. Enumeration of viable parasites was performed using limiting dilution assay. Furthermore, the animals (5 mice/group) were sacrificed two weeks post-infection. The lymph node cells were isolated and the effects of the chitinous MPs on the proliferation and production of cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10) were determined. The mean sizes of lesions were significantly smaller in chitin (0.6±0.12 mm) and chitosan treated groups (1.2±0.8 mm) than in the control group (6.2±1.7 mm) (P<0.05). The parasite load in the lymph nodes of the treated mice was significantly lower than that in the lymph nodes of controls (1.31×10(6) vs 8.24×10(7) parasite/lymph node [P=0.032] and 7.49×10(6) vs 8.24×10(7) parasite/lymph node [P=0.05] for chitin and chitosan MPs treatment, respectively). We found that chitinous MPs induced cell proliferation and that chitin but not chitosan increased TNF-α and IL-10 production. Chitin appears that it has more effect than chitosan against leishmaniasis. The current study revealed that chitinous MPs had significant activity against L. major and could be considered as new therapeutic modality in leishmaniasis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

VP24 Is a Chitin-Binding Protein Involved in White Spot Syndrome Virus Infection

PubMed Central

Li, Zaipeng; Han, Yali; Xu, Limei

2015-01-01

ABSTRACT Oral ingestion is the major route of infection for the white spot syndrome virus (WSSV). However, the mechanism by which virus particles in the digestive tract invade host cells is unknown. In the present study, we demonstrate that WSSV virions can bind to chitin through one of the major envelope proteins (VP24). Mutagenesis analysis indicated that amino acids (aa) 186 to 200 in the C terminus of VP24 were required for chitin binding. Moreover, the P-VP24186–200 peptide derived from the VP24 chitin binding region significantly inhibited the VP24-chitin interaction and the WSSV-chitin interaction, implying that VP24 participates in WSSV binding to chitin. Oral inoculation experiments showed that P-VP24186–200 treatment reduced the number of virus particles remaining in the digestive tract during the early stage of infection and greatly hindered WSSV proliferation in shrimp. These data indicate that binding of WSSV to chitin through the viral envelope protein VP24 is essential for WSSV per os infection and provide new ideas for preventing WSSV infection in shrimp farms. IMPORTANCE In this study, we show that WSSV can bind to chitin through the envelope protein VP24. The chitin-binding domain of VP24 maps to amino acids 186 to 200 in the C terminus. Binding of WSSV to chitin through the viral envelope protein VP24 is essential for WSSV per os infection. These findings not only extend our knowledge of WSSV infection but also provide new insights into strategies to prevent WSSV infection in shrimp farms. PMID:26512091

A simple procedure for preparing chitin oligomers through acetone precipitation after hydrolysis in concentrated hydrochloric acid.

PubMed

Kazami, Nao; Sakaguchi, Masayoshi; Mizutani, Daisuke; Masuda, Tatsuhiko; Wakita, Satoshi; Oyama, Fumitaka; Kawakita, Masao; Sugahara, Yasusato

2015-11-05

Chitin oligomers are of interest because of their numerous biologically relevant properties. To prepare chitin oligomers containing 4-6 GlcNAc units [(GlcNAc)4-6], α- and β-chitin were hydrolyzed with concentrated hydrochloric acid at 40 °C. The reactant was mixed with acetone to recover the acetone-insoluble material, and (GlcNAc)4-6 was efficiently recovered after subsequent water extraction. Composition analysis using gel permeation chromatography and MALDI-TOF mass spectrometry indicated that (GlcNAc)4-6 could be isolated from the acetone-insoluble material with recoveries of approximately 17% and 21% from the starting α-chitin and β-chitin, respectively. The acetone precipitation method is highly useful for recovering chitin oligomers from the acid hydrolysate of chitin. The changes in the molecular size and higher-order structure of chitin during the course of hydrolysis were also analyzed, and a model that explains the process of oligomer accumulation is proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Chitin binding proteins act synergistically with chitinases in Serratia proteamaculans 568.

PubMed

Purushotham, Pallinti; Arun, P V Parvati Sai; Prakash, Jogadhenu S S; Podile, Appa Rao

2012-01-01

Genome sequence of Serratia proteamaculans 568 revealed the presence of three family 33 chitin binding proteins (CBPs). The three Sp CBPs (Sp CBP21, Sp CBP28 and Sp CBP50) were heterologously expressed and purified. Sp CBP21 and Sp CBP50 showed binding preference to β-chitin, while Sp CBP28 did not bind to chitin and cellulose substrates. Both Sp CBP21 and Sp CBP50 were synergistic with four chitinases from S. proteamaculans 568 (Sp ChiA, Sp ChiB, Sp ChiC and Sp ChiD) in degradation of α- and β-chitin, especially in the presence of external electron donor (reduced glutathione). Sp ChiD benefited most from Sp CBP21 or Sp CBP50 on α-chitin, while Sp ChiB and Sp ChiD had major advantage with these Sp CBPs on β-chitin. Dose responsive studies indicated that both the Sp CBPs exhibit synergism ≥ 0.2 µM. The addition of both Sp CBP21 and Sp CBP50 in different ratios to a synergistic mixture did not significantly increase the activity. Highly conserved polar residues, important in binding and activity of CBP21 from S. marcescens (Sm CBP21), were present in Sp CBP21 and Sp CBP50, while Sp CBP28 had only one such polar residue. The inability of Sp CBP28 to bind to the test substrates could be attributed to the absence of important polar residues.

Chitin Binding Proteins Act Synergistically with Chitinases in Serratia proteamaculans 568

PubMed Central

Purushotham, Pallinti; Arun, P. V. Parvati Sai; Prakash, Jogadhenu S. S.; Podile, Appa Rao

2012-01-01

Genome sequence of Serratia proteamaculans 568 revealed the presence of three family 33 chitin binding proteins (CBPs). The three Sp CBPs (Sp CBP21, Sp CBP28 and Sp CBP50) were heterologously expressed and purified. Sp CBP21 and Sp CBP50 showed binding preference to β-chitin, while Sp CBP28 did not bind to chitin and cellulose substrates. Both Sp CBP21 and Sp CBP50 were synergistic with four chitinases from S. proteamaculans 568 (Sp ChiA, Sp ChiB, Sp ChiC and Sp ChiD) in degradation of α- and β-chitin, especially in the presence of external electron donor (reduced glutathione). Sp ChiD benefited most from Sp CBP21 or Sp CBP50 on α-chitin, while Sp ChiB and Sp ChiD had major advantage with these Sp CBPs on β-chitin. Dose responsive studies indicated that both the Sp CBPs exhibit synergism ≥0.2 µM. The addition of both Sp CBP21 and Sp CBP50 in different ratios to a synergistic mixture did not significantly increase the activity. Highly conserved polar residues, important in binding and activity of CBP21 from S. marcescens (Sm CBP21), were present in Sp CBP21 and Sp CBP50, while Sp CBP28 had only one such polar residue. The inability of Sp CBP28 to bind to the test substrates could be attributed to the absence of important polar residues. PMID:22590591

Discovery of chitin in skeletons of non-verongiid Red Sea demosponges.

PubMed

Ehrlich, Hermann; Shaala, Lamiaa A; Youssef, Diaa T A; Żółtowska-Aksamitowska, Sonia; Tsurkan, Mikhail; Galli, Roberta; Meissner, Heike; Wysokowski, Marcin; Petrenko, Iaroslav; Tabachnick, Konstantin R; Ivanenko, Viatcheslav N; Bechmann, Nicole; Joseph, Yvonne; Jesionowski, Teofil

2018-01-01

Marine demosponges (Porifera: Demospongiae) are recognized as first metazoans which have developed over millions of years of evolution effective survival strategies based on unique metabolic pathways to produce both biologically active secondary metabolites and biopolymer-based stiff skeletons with 3D architecture. Up to date, among marine demosponges, only representatives of the Verongiida order have been known to synthetize biologically active substances as well as skeletons made of structural polysaccharide chitin. This work, to our knowledge, demonstrates for the first time that chitin is an important structural component within skeletons of non-verongiid demosponges Acarnus wolffgangi and Echinoclathria gibbosa collected in the Red Sea. Calcofluor white staining, FTIR and Raman analysis, ESI-MS, SEM, and fluorescence microscopy as well as a chitinase digestion assay were applied in order to confirm, with strong evidence, the finding of α-chitin in the skeleton of both species. We suggest that, the finding of chitin within these representatives of Poecilosclerida order is a promising step in the evaluation of these sponges as novel renewable sources for both biologically active metabolites and chitin, which are of prospective application for pharmacology and biomedicine.

The demosponge Pseudoceratina purpurea as a new source of fibrous chitin.

PubMed

Żółtowska-Aksamitowska, Sonia; Tsurkan, Mikhail V; Lim, Swee-Cheng; Meissner, Heike; Tabachnick, Konstantin; Shaala, Lamiaa A; Youssef, Diaa T A; Ivanenko, Viatcheslav N; Petrenko, Iaroslav; Wysokowski, Marcin; Bechmann, Nicole; Joseph, Yvonne; Jesionowski, Teofil; Ehrlich, Hermann

2018-06-01

Among marine demosponges (Porifera: Demospongiae), only representatives of the order Verongiida have been recognized to synthetize both biologically active substances as well as scaffolds-like fibrous skeletons made of structural aminopolysaccharide chitin. The unique 3D architecture of such scaffolds open perspectives for their applications in waste treatment, biomimetics and tissue engineering. Here, we focus special attention to the demosponge Pseudoceratina purpurea collected in the coastal waters of Singapore. For the first time the detailed description of the isolation of chitin from the skeleton of this sponge and its identification using diverse bioanalytical tools were carried out. Calcofluor white staining, FTIR analysis, electrospray ionization mass spectrometry (ESI-MS), SEM, and fluorescence microscopy as well as a chitinase digestion assay were applied in order to confirm with strong evidence the finding of alpha-chitin in the skeleton of P. purpurea. We suggest that the discovery of chitin within representatives of Pseudoceratinidae family is a perspective step in evaluation of these verongiid sponges as novel renewable sources for both chitin and biologically active metabolites, which are of prospective use for marine oriented biomedicine and pharmacology, respectively. Copyright © 2018 Elsevier B.V. All rights reserved.

Application of Spectroscopic Methods for Structural Analysis of Chitin and Chitosan

PubMed Central

Kumirska, Jolanta; Czerwicka, Małgorzata; Kaczyński, Zbigniew; Bychowska, Anna; Brzozowski, Krzysztof; Thöming, Jorg; Stepnowski, Piotr

2010-01-01

Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds. PMID:20559489

Characterization and role of a metalloprotease induced by chitin in Serratia sp. KCK.

PubMed

Kim, Hyun-Soo; Golyshin, Peter N; Timmis, Kenneth N

2007-11-01

A metalloprotease induced by chitin in a new chitinolytic bacterium Serratia sp. Strain KCK was purified and characterized. Compared with other Serratia enzymes, it exhibited a rather broad pH activity range (pH 5.0-8.0), and thermostability. The cognate ORF, mpr, was cloned and expressed. Its deduced amino acid sequence showed high similarity to those of bacterial zinc-binding metalloproteases and a well-conserved serralysin family motif. Pretreatment of chitin with the Mpr protein promoted chitin degradation by chitinase A, which suggests that Mpr participates in, and facilitates, chitin degradation by this microorganism.

Anticancer activity of silver and copper embedded chitin nanocomposites against human breast cancer (MCF-7) cells.

PubMed

Solairaj, Dhanasekaran; Rameshthangam, Palanivel; Arunachalam, Gnanapragasam

2017-12-01

Chitin is a natural biopolymer widely used in biomedical and environmental applications due to its distinctive physical, chemical and mechanical properties. Although the anticancer property of chitin nanoforms and chitin derivatives against various cancers were studied earlier, there is no report in the chitin nanostructure incorporated metal nanocomposite. The present study was aimed to investigate the cytotoxicity of chitin incorporated silver and copper nanocomposite against human breast cancer (MCF-7) cells. Cytotoxicity of chitin nanoparticles (CNP), silver nanoparticles (AgNP), copper nanoparticles (CuNP), chitin/silver nanocomposite (CNP/AgNP) and chitin/copper nanocomposite (CNP/CuNP) was evaluated. Among all the above, CNP/AgNP has shown a lower of 31 mg as inhibitory concentration (IC 50 ) value. Our study further showed the increased generation of reactive oxygen species with decreased activity of antioxidant enzymes and damage in the membrane integrity, thus confirms the cellular cytotoxic action of CNP/AgNP. In conclusion, the present study validates that, incorporating chitin nanoparticles with metallic nanostructure could be an effective and promising therapeutic agent against breast cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

An overview of chitin or chitosan/nano ceramic composite scaffolds for bone tissue engineering.

PubMed

Deepthi, S; Venkatesan, J; Kim, Se-Kwon; Bumgardner, Joel D; Jayakumar, R

2016-12-01

Chitin and chitosan based nanocomposite scaffolds have been widely used for bone tissue engineering. These chitin and chitosan based scaffolds were reinforced with nanocomponents viz Hydroxyapatite (HAp), Bioglass ceramic (BGC), Silicon dioxide (SiO 2 ), Titanium dioxide (TiO 2 ) and Zirconium oxide (ZrO 2 ) to develop nanocomposite scaffolds. Plenty of works have been reported on the applications and characteristics of the nanoceramic composites however, compiling the work done in this field and presenting it in a single article is a thrust area. This review is written with an aim to fill this gap and focus on the preparations and applications of chitin or chitosan/nHAp, chitin or chitosan/nBGC, chitin or chitosan/nSiO 2 , chitin or chitosan/nTiO 2 and chitin or chitosan/nZrO 2 in the field of bone tissue engineering in detail. Many reports so far exemplify the importance of ceramics in bone regeneration. The effect of nanoceramics over native ceramics in developing composites, its role in osteogenesis etc. are the gist of this review. Copyright © 2016 Elsevier B.V. All rights reserved.

Self-bonded composite films based on cellulose nanofibers and chitin nanocrystals as antifungal materials.

PubMed

Robles, Eduardo; Salaberria, Asier M; Herrera, Rene; Fernandes, Susana C M; Labidi, Jalel

2016-06-25

Cellulose nanofibers and chitin nanocrystals, two main components of agricultural and aquacultural by-products, were obtained from blue agave and yellow squat lobster industrial residues. Cellulose nanofibers were obtained using high pressure homogenization, while chitin nanocrystals were obtained by hydrolysis in acid medium. Cellulose nanofibers and chitin nanocrystals were characterized by X-ray diffraction, Atomic Force Microscopy and Infrared spectroscopy. Self-bonded composite films with different composition were fabricated by hot pressing and their properties were evaluated. Antifungal activity of chitin nanocrystals was studied using a Cellometer(®) cell count device, mechanical properties at tension were measured with a universal testing machine, water vapor permeability was evaluated with a thermohygrometer and surface tension with sessile drop contact angle method. The addition of chitin nanocrystals reduced slightly the mechanical properties of the composite. Presence of chitin nanocrystals influenced the growth of Aspergillus sp fungus in the surface of the composites as expected. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fabrication of magnetic and fluorescent chitin and dibutyrylchitin sub-micron particles by oil-in-water emulsification.

PubMed

Blanco-Fernandez, Barbara; Chakravarty, Shatadru; Nkansah, Michael K; Shapiro, Erik M

2016-11-01

Chitin is a carbohydrate polymer with unique pharmacological and immunological properties, however, because of its unwieldy chemistry, the synthesis of discreet sized sub-micron particles has not been well reported. This work describes a facile and flexible method to fabricate biocompatible chitin and dibutyrylchitin sub-micron particles. This technique is based on an oil-in-water emulsification/evaporation method and involves the hydrophobization of chitin by the addition of labile butyryl groups onto chitin, disrupting intermolecular hydrogen bonds and enabling solubility in the organic solvent used as the oil phase during fabrication. The subsequent removal of butyryl groups post-fabrication through alkaline saponification regenerates native chitin while keeping particles morphology intact. Examples of encapsulation of hydrophobic dyes and nanocrystals are demonstrated, specifically using iron oxide nanocrystals and coumarin 6. The prepared particles had diameters between 300-400nm for dibutyrylchitin and 500-600nm for chitin and were highly cytocompatible. Moreover, they were able to encapsulate high amounts of iron oxide nanocrystals and were able to label mammalian cells. We describe a technique to prepare sub-micron particles of highly acetylated chitin (>90%) and dibutyrylchitin and demonstrate their utility as carriers for imaging. Chitin is a polysaccharide capable of stimulating the immune system, a property that depends on the acetamide groups, but its insolubility limits its use. No method for sub-micron particle preparation with highly acetylated chitins have been published. The only approach for the preparation of sub-micron particles uses low acetylation chitins. Dibutyrylchitin, a soluble chitin derivative, was used to prepare particles by oil in water emulsification. Butyryl groups were then removed, forming chitin particles. These particles could be suitable for encapsulation of hydrophobic payloads for drug delivery and cell imaging, as well as

Structural effect of quaternary ammonium chitin derivatives on their bactericidal activity and specificity.

PubMed

Morkaew, Tirut; Pinyakong, Onruthai; Tachaboonyakiat, Wanpen

2017-08-01

The effect of the quaternary ammonium chitin structure on the bactericidal activity and specificity against Escherichia coli and Staphylococcus aureus was investigated. Quaternary ammonium chitins were synthesized by the separate acylation of chitin (CT) with carboxymethyl trimethylammonium chloride (CMA), 3-carboxypropyl trimethylammonium chloride (CPA) and N-dodecyl-N,N-(dimethylammonio)butyrate (DDMAB). The successful acylation was confirmed by newly formed ester linkage. All three derivatives had a higher surface charge than chitin due to the additional positively charged quaternary ammonium groups. The N-short alkyl substituent (methyl) of CTCMA and CTCPA increased the hydrophilicity whilst the N-long alkyl substituent (dodecyl) of CTDDMAB increased the hydrophobicity compared to chitin. Chitin did not exhibit any bactericidal activity, while CTCMA and CTCPA completely killed E. coli and S. aureus in 30 and 60min, respectively, and CTDDMAB completely killed S. aureus in 10min but did not kill E. coli after a 2-h exposure. Therefore, the N-short alkyl substituent was more effective for killing E. coli and the N-long alkyl substituent conferred specific bactericidal activity against S. aureus. Copyright © 2017 Elsevier B.V. All rights reserved.

Squid-derived chitin oligosaccharides are a chemotactic signal during colonization by Vibrio fischeri.

PubMed

Mandel, Mark J; Schaefer, Amy L; Brennan, Caitlin A; Heath-Heckman, Elizabeth A C; Deloney-Marino, Cindy R; McFall-Ngai, Margaret J; Ruby, Edward G

2012-07-01

Chitin, a polymer of N-acetylglucosamine (GlcNAc), is noted as the second most abundant biopolymer in nature. Chitin serves many functions for marine bacteria in the family Vibrionaceae ("vibrios"), in some instances providing a physical attachment site, inducing natural genetic competence, and serving as an attractant for chemotaxis. The marine luminous bacterium Vibrio fischeri is the specific symbiont in the light-emitting organ of the Hawaiian bobtail squid, Euprymna scolopes. The bacterium provides the squid with luminescence that the animal uses in an antipredatory defense, while the squid supports the symbiont's nutritional requirements. V. fischeri cells are harvested from seawater during each host generation, and V. fischeri is the only species that can complete this process in nature. Furthermore, chitin is located in squid hemocytes and plays a nutritional role in the symbiosis. We demonstrate here that chitin oligosaccharides produced by the squid host serve as a chemotactic signal for colonizing bacteria. V. fischeri uses the gradient of host chitin to enter the squid light organ duct and colonize the animal. We provide evidence that chitin serves a novel function in an animal-bacterial mutualism, as an animal-produced bacterium-attracting synomone.

Characterization of Chitin and Chitosan Molecular Structure in Aqueous Solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franca, Eduardo D.; Lins, Roberto D.; Freitas, Luiz C.

Molecular dynamics simulations have been used to characterize the structure of chitin and chitosan fibers in aqueous solutions. Chitin fibers, whether isolated or in the form of a β-chitin nanoparticle, adopt the so-called 2-fold helix with Φ and φ values similar to its crystalline state. In solution, the intramolecular hydrogen bond HO3(n)•••O5(n+1) responsible for the 2-fold helical motif is stabilized by hydrogen bonds with water molecules in a well-defined orientation. On the other hand, chitosan can adopt five distinct helical motifs and its conformational equilibrium is highly dependent on pH. The hydrogen bond pattern and solvation around the O3 atommore » of insoluble chitosan (basic pH) are nearly identical to these quantities in chitin. Our findings suggest that the solubility and conformation of these polysaccharides are related to the stability of the intrachain HO3(n)•••O5(n+1) hydrogen bond, which is affect by the water exchange around the O3-HO3 hydroxyl group.« less

Preparation, assessment, and comparison of α-chitin nano-fiber films with different surface charges

NASA Astrophysics Data System (ADS)

Zhang, Yan; Jiang, Jie; Liu, Liang; Zheng, Ke; Yu, Shiyuan; Fan, Yimin

2015-05-01

Chitin nano-fibers with positive and negative charges have been, respectively, produced from partially deacetylated and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidized α-chitin. The average diameters and lengths of the TEMPO-oxidized chitin nano-fibers (TOChN) were 14 ± 4.3 and 190 ± 140 nm, respectively, and the average diameters and lengths of the partially deacetylated chitin nano-fibers (DEChN) were 6 ± 1.7 and 320 ± 105 nm, respectively. A partially deacetylated chitin nano-fiber film (DEChN-F), a TEMPO-mediated and oxidized chitin nano-fiber film (TOChN-F), and a composite film (DE-TO-ChN-F) consisting of a combination of the two were prepared by drying the dispersions at 40 °C. The DEChN-F, TOChN-F, and DE-TO-ChN-F all have similar tensile strengths of approximately 90 MPa; however, the chitosan film (Chitosan-F) had a tensile strength of approximately 30 MPa. In addition, TOChN-F and DE-TO-ChN-F have a thermal weight loss at 210 °C, and DEChN-F has a thermal weight loss at 280 °C. DEChN-F was found to have antimicrobial activity with regards to Escherichia coli. Finally, the chitin nano-fiber films could be slightly degraded by cellulase, which provided a novel biological performance of the chitin nano-material.

Accumulation of N-Acetylglucosamine Oligomers in the Plant Cell Wall Affects Plant Architecture in a Dose-Dependent and Conditional Manner1[W][OPEN

PubMed Central

Vanholme, Bartel; Vanholme, Ruben; Turumtay, Halbay; Goeminne, Geert; Cesarino, Igor; Goubet, Florence; Morreel, Kris; Rencoret, Jorge; Bulone, Vincent; Hooijmaijers, Cortwa; De Rycke, Riet; Gheysen, Godelieve; Ralph, John; De Block, Marc; Meulewaeter, Frank; Boerjan, Wout

2014-01-01

To study the effect of short N-acetylglucosamine (GlcNAc) oligosaccharides on the physiology of plants, N-ACETYLGLUCOSAMINYLTRANSFERASE (NodC) of Azorhizobium caulinodans was expressed in Arabidopsis (Arabidopsis thaliana). The corresponding enzyme catalyzes the polymerization of GlcNAc and, accordingly, β-1,4-GlcNAc oligomers accumulated in the plant. A phenotype characterized by difficulties in developing an inflorescence stem was visible when plants were grown for several weeks under short-day conditions before transfer to long-day conditions. In addition, a positive correlation between the oligomer concentration and the penetrance of the phenotype was demonstrated. Although NodC overexpression lines produced less cell wall compared with wild-type plants under nonpermissive conditions, no indications were found for changes in the amount of the major cell wall polymers. The effect on the cell wall was reflected at the transcriptome level. In addition to genes encoding cell wall-modifying enzymes, a whole set of genes encoding membrane-coupled receptor-like kinases were differentially expressed upon GlcNAc accumulation, many of which encoded proteins with an extracellular Domain of Unknown Function26. Although stress-related genes were also differentially expressed, the observed response differed from that of a classical chitin response. This is in line with the fact that the produced chitin oligomers were too small to activate the chitin receptor-mediated signal cascade. Based on our observations, we propose a model in which the oligosaccharides modify the architecture of the cell wall by acting as competitors in carbohydrate-carbohydrate or carbohydrate-protein interactions, thereby affecting noncovalent interactions in the cell wall or at the interface between the cell wall and the plasma membrane. PMID:24664205

Analysis of chitin-binding proteins from Manduca sexta provides new insights into evolution of peritrophin A-type chitin-binding domains in insects.

PubMed

Tetreau, Guillaume; Dittmer, Neal T; Cao, Xiaolong; Agrawal, Sinu; Chen, Yun-Ru; Muthukrishnan, Subbaratnam; Haobo, Jiang; Blissard, Gary W; Kanost, Michael R; Wang, Ping

2015-07-01

In insects, chitin is a major structural component of the cuticle and the peritrophic membrane (PM). In nature, chitin is always associated with proteins among which chitin-binding proteins (CBPs) are the most important for forming, maintaining and regulating the functions of these extracellular structures. In this study, a genome-wide search for genes encoding proteins with ChtBD2-type (peritrophin A-type) chitin-binding domains (CBDs) was conducted. A total of 53 genes encoding 56 CBPs were identified, including 15 CPAP1s (cuticular proteins analogous to peritrophins with 1 CBD), 11 CPAP3s (CPAPs with 3 CBDs) and 17 PMPs (PM proteins) with a variable number of CBDs, which are structural components of cuticle or of the PM. CBDs were also identified in enzymes of chitin metabolism including 6 chitinases and 7 chitin deacetylases encoded by 6 and 5 genes, respectively. RNA-seq analysis confirmed that PMP and CPAP genes have differential spatial expression patterns. The expression of PMP genes is midgut-specific, while CPAP genes are widely expressed in different cuticle forming tissues. Phylogenetic analysis of CBDs of proteins in insects belonging to different orders revealed that CPAP1s from different species constitute a separate family with 16 different groups, including 6 new groups identified in this study. The CPAP3s are clustered into a separate family of 7 groups present in all insect orders. Altogether, they reveal that duplication events of CBDs in CPAP1s and CPAP3s occurred prior to the evolutionary radiation of insect species. In contrast to the CPAPs, all CBDs from individual PMPs are generally clustered and distinct from other PMPs in the same species in phylogenetic analyses, indicating that the duplication of CBDs in each of these PMPs occurred after divergence of insect species. Phylogenetic analysis of these three CBP families showed that the CBDs in CPAP1s form a clearly separate family, while those found in PMPs and CPAP3s were clustered

Effect of Acetyl Group on Mechanical Properties of Chitin/Chitosan Nanocrystal: A Molecular Dynamics Study

PubMed Central

Cui, Junhe; Yu, Zechuan; Lau, Denvid

2016-01-01

Chitin fiber is the load-bearing component in natural chitin-based materials. In these materials, chitin is always partially deacetylated to different levels, leading to diverse material properties. In order to understand how the acetyl group enhances the fracture resistance capability of chitin fiber, we constructed atomistic models of chitin with varied acetylation degree and analyzed the hydrogen bonding pattern, fracture, and stress-strain behavior of these models. We notice that the acetyl group can contribute to the formation of hydrogen bonds that can stabilize the crystalline structure. In addition, it is found that the specimen with a higher acetylation degree presents a greater resistance against fracture. This study describes the role of the functional group, acetyl groups, in crystalline chitin. Such information could provide preliminary understanding of nanomaterials when similar functional groups are encountered. PMID:26742033

Experimental evaluation of new chitin-chitosan graft for duraplasty.

PubMed

Pogorielov, M; Kravtsova, A; Reilly, G C; Deineka, V; Tetteh, G; Kalinkevich, O; Pogorielova, O; Moskalenko, R; Tkach, G

2017-02-01

Natural materials such as collagen and alginate have promising applications as dural graft substitutes. These materials are able to restore the dural defect and create optimal conditions for the development of connective tissue at the site of injury. A promising material for biomedical applications is chitosan-a linear polysaccharide obtained by the deacetylation of chitin. It has been found to be nontoxic, biodegradable, biofunctional and biocompatible in addition to having antimicrobial characteristics. In this study we designed new chitin-chitosan substitutes for dura mater closure and evaluated their effectiveness and safety. Chitosan films were produced from 3 % of chitosan (molar mass-200, 500 or 700 kDa, deacetylation rate 80-90%) with addition of 20% of chitin. Antimicrobial effictively and cell viability were analysed for the different molar masses of chitosan. The film containing chitosan of molar mass 200 kDa, had the best antimicrobial and biological activity and was successfully used for experimental duraplasty in an in vivo model. In conclusion the chitin-chitosan membrane designed here met the requirements for a dura matter graft exhibiting the ability to support cell growth, inhibit microbial growth and biodegradade at an appropriate rate. Therefore this is a promising material for clinical duroplasty.

Lignin composition is more important than content for maize stem cell wall degradation.

PubMed

He, Yuan; Mouthier, Thibaut Mb; Kabel, Mirjam A; Dijkstra, Jan; Hendriks, Wouter H; Struik, Paul C; Cone, John W

2018-01-01

The relationship between the chemical and molecular properties - in particular the (acid detergent) lignin (ADL) content and composition expressed as the ratio between syringyl and guaiacyl compounds (S:G ratio) - of maize stems and in vitro gas production was studied in order to determine which is more important in the degradability of maize stem cell walls in the rumen of ruminants. Different internodes from two contrasting maize cultivars (Ambrosini and Aastar) were harvested during the growing season. The ADL content decreased with greater internode number within the stem, whereas the ADL content fluctuated during the season for both cultivars. The S:G ratio was lower in younger tissue (greater internode number or earlier harvest date) in both cultivars. For the gas produced between 3 and 20 h, representing the fermentation of cell walls in rumen fluid, a stronger correlation (R 2 = 0.80) was found with the S:G ratio than with the ADL content (R 2 = 0.68). The relationship between ADL content or S:G ratio and 72-h gas production, representing total organic matter degradation, was weaker than that with gas produced between 3 and 20 h. The S:G ratio plays a more dominant role than ADL content in maize stem cell wall degradation. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Chitin synthases are required for survival, fecundity and egg-hatch in the red flour beetle, Tribolium castaneum

USDA-ARS?s Scientific Manuscript database

The synthesis of chitin, the Beta-1,4-linked polymer of N-acetylglucosamine, is catalyzed by chitin synthase (CHS). Chitin is essential for the structural integrity of the exoskeletal cuticle and midgut peritrophic membrane (PM) of insects. To study the functions of the two chitin synthase genes, ...

Viscoelastic behavior of mineralized (CaCO3) chitin based PVP-CMC hydrogel scaffolds

NASA Astrophysics Data System (ADS)

Čadež, Vida; Saha, Nabanita; Sikirić, Maja Dutour; Saha, Petr

2017-05-01

Enhancement of the mechanical as well as functional properties of the perspective mineralized PVP-CMC-CaCO3 hydrogel scaffold applicable for bone tissue engineering is quite essential. Therefore, the incorporation feasibility of chitin, a bioactive, antibacterial and biodegradable material, was examined in order to test its ability to enchance mechanical properties of the PVP-CMC-CaCO3 hydrogel scaffold. Chitin based PVP-CMC hydrogels were prepared and characterized both as non-mineralized and mineralized (CaCO3) form of hydrogel scaffolds. Both α-chitin (commercially bought) and β-chitin (isolated from the cuttlebone) were individually tested. It was observed that at 1% strain all hydrogel scaffolds have linear trend, with highly pronounced elastic properties in comparison to viscous ones. The complex viscosity has directly proportional behavior with negative slope against angular frequency within the range of ω = 0.1 - 100 rad.s-1. Incorporation of β-chitin increased storage modulus of all mineralized samples, making it interesting for further research.

Chitin based heteroatom-doped porous carbon as electrode materials for supercapacitors.

PubMed

Zhou, Jie; Bao, Li; Wu, Shengji; Yang, Wei; Wang, Hui

2017-10-01

Chitin biomass has received much attention as an amino-functional polysaccharide precursor for synthesis of carbon materials. Rich nitrogen and oxygen dual-doped porous carbon derived from cicada slough (CS), a renewable biomass mainly composed of chitin, was synthesized and employed as electrode materials for electrochemical capacitors, for the first time ever. The cicada slough-derived carbon (CSC) was prepared by a facile process via pre-carbonization in air, followed by KOH activation. The weight ratio of KOH and char plays an important role in fabricating the microporous structure and tuning the surface chemistry of CSC. The obtained CSC had a large specific surface area (1243-2217m 2 g -1 ), fairly high oxygen content (28.95-33.78 at%) and moderate nitrogen content (1.47-4.35 at%). The electrochemical performance of the CS char and CSC as electrodes for capacitors was evaluated in a three-electrode cell configuration with 6M KOH as the electrolyte. Electrochemical studies showed that the as-prepared CSC activated at the KOH-to-char weight ratio of 2 exhibited the highest specific capacitance (266.5Fg -1 at a current density of 0.5Ag -1 ) and excellent rate capability (196.2Fg -1 remained at 20Ag -1 ) and cycle durability. In addition, the CSC-2-based symmetrical device possessed the desirable energy density and power density of about 15.97Whkg -1 and 5000Wkg -1 at 5Ag -1 , respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spontaneous Chitin Accumulation in Airways and Age-Related Fibrotic Lung Disease.

PubMed

Van Dyken, Steven J; Liang, Hong-Erh; Naikawadi, Ram P; Woodruff, Prescott G; Wolters, Paul J; Erle, David J; Locksley, Richard M

2017-04-20

The environmentally widespread polysaccharide chitin is degraded and recycled by ubiquitous bacterial and fungal chitinases. Although vertebrates express active chitinases from evolutionarily conserved loci, their role in mammalian physiology is unclear. We show that distinct lung epithelial cells secrete acidic mammalian chitinase (AMCase), which is required for airway chitinase activity. AMCase-deficient mice exhibit premature morbidity and mortality, concomitant with accumulation of environmentally derived chitin polymers in the airways and expression of pro-fibrotic cytokines. Over time, these mice develop spontaneous pulmonary fibrosis, which is ameliorated by restoration of lung chitinase activity by genetic or therapeutic approaches. AMCase-deficient epithelial cells express fibrosis-associated gene sets linked with cell stress pathways. Mice with lung fibrosis due to telomere dysfunction and humans with interstitial lung disease also accumulate excess chitin polymers in their airways. These data suggest that altered chitin clearance could exacerbate fibrogenic pathways in the setting of lung diseases characterized by epithelial cell dysfunction. Copyright © 2017 Elsevier Inc. All rights reserved.

Preparation, assessment, and comparison of α-chitin nano-fiber films with different surface charges.

PubMed

Zhang, Yan; Jiang, Jie; Liu, Liang; Zheng, Ke; Yu, Shiyuan; Fan, Yimin

2015-01-01

Chitin nano-fibers with positive and negative charges have been, respectively, produced from partially deacetylated and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidized α-chitin. The average diameters and lengths of the TEMPO-oxidized chitin nano-fibers (TOChN) were 14 ± 4.3 and 190 ± 140 nm, respectively, and the average diameters and lengths of the partially deacetylated chitin nano-fibers (DEChN) were 6 ± 1.7 and 320 ± 105 nm, respectively. A partially deacetylated chitin nano-fiber film (DEChN-F), a TEMPO-mediated and oxidized chitin nano-fiber film (TOChN-F), and a composite film (DE-TO-ChN-F) consisting of a combination of the two were prepared by drying the dispersions at 40 °C. The DEChN-F, TOChN-F, and DE-TO-ChN-F all have similar tensile strengths of approximately 90 MPa; however, the chitosan film (Chitosan-F) had a tensile strength of approximately 30 MPa. In addition, TOChN-F and DE-TO-ChN-F have a thermal weight loss at 210 °C, and DEChN-F has a thermal weight loss at 280 °C. DEChN-F was found to have antimicrobial activity with regards to Escherichia coli. Finally, the chitin nano-fiber films could be slightly degraded by cellulase, which provided a novel biological performance of the chitin nano-material.

Inside-the-wall detection of objects with low metal content using the GPR sensor: effects of different wall structures on the detection performance

NASA Astrophysics Data System (ADS)

Dogan, Mesut; Yesilyurt, Omer; Turhan-Sayan, Gonul

2018-04-01

Ground penetrating radar (GPR) is an ultra-wideband electromagnetic sensor used not only for subsurface sensing but also for the detection of objects which may be hidden behind a wall or inserted within the wall. Such applications of the GPR technology are used in both military and civilian operations such as mine or IED (improvised explosive device) detection, rescue missions after earthquakes and investigation of archeological sites. Detection of concealed objects with low metal content is known to be a challenging problem in general. Use of A-scan, B-scan and C-scan GPR data in combination provides valuable information for target recognition in such applications. In this paper, we study the problem of target detection for potentially explosive objects embedded inside a wall. GPR data is numerically simulated by using an FDTD-based numerical computation tool when dielectric targets and targets with low metal content are inserted into different types of walls. A small size plastic bottle filled with trinitrotoluene (TNT) is used as the target with and without a metal fuse in it. The targets are buried into two different types of wall; a homogeneous brick wall and an inhomogeneous wall constructed by bricks having periodically located air holes in it. Effects of using an inhomogeneous wall structure with internal boundaries are investigated as a challenging scenario, paying special attention to preprocessing.

Crystallinity of chitin and carbonate mineral components independently record crustacean biomineralization

NASA Astrophysics Data System (ADS)

Mergelsberg, S. T.; Michel, F. M.; Mukhopadhyay, B.; Dove, P. M.

2016-02-01

Some of the earliest evidence for crustacean organisms is attributed to the discovery of Peytoia nathorsti, a predatory arthropod from 500 Ma (Cong, P. et al., 2014). These animals presumably began with a soft exoskeleton and evolved to fill diverse ecological niches while adopting a mineralized skeleton that is rarely preserved in its entirety (Klompmaker, A.A. et al., 2015). That is, one or more of the primary skeleton components (calcium carbonate minerals, the polysaccharide chitin, and minor proteins) were subject to decomposition during fossilization and preservation. These missing pieces present a significant obstacle to reconstructing ecosystem variability over long time periods. Our recent study of the exoskeletons from ten Malacostraca species suggests the physical and chemical structure of chitin holds promise as a secondary proxy for reconstructing skeleton reinforcement. Using high-energy X-ray diffraction and a novel Raman spectroscopy technique to enhance resolution, we determined the detailed nanostructures of chitin and the associated calcium carbonate minerals that comprise the cuticles of multiple body parts. Crab cuticles from the order Brachyura (Dungeness and Rock crabs) exhibit elevated crystallinities of the chitin and calcite in the more reinforced structures (such as the claw). In contrast, the cuticle of lobster body parts show a much greater variability of calcium carbonate crystallinity and a very consistent crystallinity of chitin. Calcite and chitin crystallinity exhibit a dependency within a species (body part to body part), but these dependencies can be different between taxa. Insights from this study suggest high resolution structural analyses hold promise for developing new proxies for the paleo-environment and paleo-ecology of specific Malacostraca animals, regardless of how well the specimen is preserved.

The use of flow cytometry to monitor chitin synthesis in regenerating protoplasts of Candida albicans.

PubMed

Hector, R F; Braun, P C; Hart, J T; Kamarck, M E

1990-01-01

Flow cytometry was used to monitor chitin synthesis in regenerating protoplasts of the yeast Candida albicans. Comparisons of cells stained with Calcofluor White, a fluorochrome with known affinity for chitin, and cells incubated in the presence of N-[3H]-acetylglucosamine, the precursor substrate for chitin, showed a linear relationship between fluorescence and incorporation of label over time. Changes in both the fluorescence and light scatter of regenerating protoplasts treated with inhibitors of fungal chitin synthase were also quantitated by flow cytometry.

Adaptation of Candida albicans to environmental pH induces cell wall remodelling and enhances innate immune recognition

PubMed Central

Sorsby, Eleanor; Mahtey, Nabeel; Brown, Ian

2017-01-01

Candida albicans is able to proliferate in environments that vary dramatically in ambient pH, a trait required for colonising niches such as the stomach, vaginal mucosal and the GI tract. Here we show that growth in acidic environments involves cell wall remodelling which results in enhanced chitin and β-glucan exposure at the cell wall periphery. Unmasking of the underlying immuno-stimulatory β-glucan in acidic environments enhanced innate immune recognition of C. albicans by macrophages and neutrophils, and induced a stronger proinflammatory cytokine response, driven through the C-type lectin-like receptor, Dectin-1. This enhanced inflammatory response resulted in significant recruitment of neutrophils in an intraperitoneal model of infection, a hallmark of symptomatic vaginal colonisation. Enhanced chitin exposure resulted from reduced expression of the cell wall chitinase Cht2, via a Bcr1-Rim101 dependent signalling cascade, while increased β-glucan exposure was regulated via a non-canonical signalling pathway. We propose that this “unmasking” of the cell wall may induce non-protective hyper activation of the immune system during growth in acidic niches, and may attribute to symptomatic vaginal infection. PMID:28542528

Mining marine shellfish wastes for bioactive molecules: chitin and chitosan--Part A: extraction methods.

PubMed

Hayes, Maria; Carney, Brian; Slater, John; Brück, Wolfram

2008-07-01

Legal restrictions, high costs and environmental problems regarding the disposal of marine processing wastes have led to amplified interest in biotechnology research concerning the identification and extraction of additional high grade, low-volume by-products produced from shellfish waste treatments. Shellfish waste consisting of crustacean exoskeletons is currently the main source of biomass for chitin production. Chitin is a polysaccharide composed of N-acetyl-D-glucosamine units and the multidimensional utilization of chitin derivatives including chitosan, a deacetylated derivative of chitin, is due to a number of characteristics including: their polyelectrolyte and cationic nature, the presence of reactive groups, high adsorption capacities, bacteriostatic and fungistatic influences, making them very versatile biomolecules. Part A of this review aims to consolidate useful information concerning the methods used to extract and characterize chitin, chitosan and glucosamine obtained through industrial, microbial and enzymatic hydrolysis of shellfish waste.

Roles of the Skn7 response regulator in stress resistance, cell wall integrity and GA biosynthesis in Ganoderma lucidum.

PubMed

Wang, Shengli; Shi, Liang; Hu, Yanru; Liu, Rui; Ren, Ang; Zhu, Jing; Zhao, Mingwen

2018-05-01

The transcription factor Skn7 is a highly conserved fungal protein that participates in a variety of processes, including oxidative stress adaptation, fungicide sensitivity, cell wall biosynthesis, cell cycle, and sporulation. In this study, a homologous gene of Saccharomyces cerevisiae Skn7 was cloned from Ganoderma lucidum. RNA interference (RNAi) was used to study the functions of Skn7, and the two knockdown strains Skn7i-5 and Skn7i-7 were obtained in G. lucidum. The knockdown of GlSkn7 resulted in hypersensitivity to oxidative and cell wall stresses. The concentrations of chitin and β-1,3-glucan distinctly decreased in the GlSkn7 knockdown strains compared with those of the wild type (WT). In addition, the expression of cell wall biosynthesis related genes was also significantly down-regulated and the thickness of the cell wall also significantly reduced in the GlSkn7 knockdown strains. The intracellular reactive oxygen species (ROS) content and ganoderic acids biosynthesis increased significantly in the GlSkn7 knockdown strains. Interestingly, the level of intracellular ROS and the content of ganoderic acids decreased after N-acetyl-L-cysteine (NAC), an ROS scavenger, was added, indicating that GlSkn7 might regulate ganoderic acids biosynthesis via the intracellular ROS level. The transcript level of GlSkn7 were up-regulated in osmotic stress, heat stress and fungicide condition. At the same time, the content of ganoderic acids in the GlSkn7 knockdown strains also changed distinctly in these conditions. Overall, GlSkn7 is involved in stress resistance, cell wall integrity and ganoderic acid biosynthesis in G. lucidum. Copyright © 2018 Elsevier Inc. All rights reserved.

Preparation of Chitin Nanofibers-Gold Metallic Nanocomposite by Phase Transfer Method

NASA Astrophysics Data System (ADS)

Shervani, Zameer; Taisuke, Yukawa; Ifuku, Shinsuke; Saimoto, Hiroyuki; Morimoto, Minoru

2012-10-01

Chitin nanofibers (CNFs)-Au(0) nanoparticles (Au NPs) blends in dispersion, flakes and thin film or sheet forms were first prepared by mixing pre-organized Au NPs prepared in triblock copolymer with diluted CNFs suspension. Water soluble polymer triblock copolymer poly (methyl vinyl ether, PMVE) in the amount 0.6 wt.% was used to prepare NPs and 0.12 wt.% net chitin content was used as CNFs suspension to prepare the blended composite. Au NPs of size 4.4 nm (σ = 1.2) were obtained when Au salt (HAuCl4ṡ3H2O (hydrogen tetrachloroaurate (III) trihydrate) was reduced by 5 equivalents of NaBH4. PMVE polymer acted as a stabilizing or capping agent for pre-organized NPs. Completion of reaction was fast, all salt reduced to metallic form in just 15 min after the addition of NaBH4. CNFs (1 wt.% chitin) which was used to prepare CNFs-Au NPs blend composite were prepared from crab shell in never dried acidic condition by established combination of chemical and mechanical processes that gave 25-40 nm width and high aspect ratio CNFs. When polymer capped Au NPs mixed with CNF suspension, all Au NPs and 56% polymer were mass transferred from water phase to entangle with more polar moieties of CNFs-water suspension as no trace of Au NPs were noticed in water-polymer mother liquor after blending with CNFs suspension. Particles size of CNFs-Au NPs composite was measured by employing TEM, SAXS and SEM techniques. CNFs-Au NPs composite were characterized in solution and compressed dried sheet form by recording digital images, UV-vis and XRD spectroscopies. CNFs-Au NPs suspension had antibacterial activity against gram positive bacteria S. aureus.

Embryonic desiccation resistance in Aedes aegypti: presumptive role of the chitinized Serosal Cuticle

PubMed Central

Rezende, Gustavo Lazzaro; Martins, Ademir Jesus; Gentile, Carla; Farnesi, Luana Cristina; Pelajo-Machado, Marcelo; Peixoto, Alexandre Afrânio; Valle, Denise

2008-01-01

Background One of the major problems concerning dengue transmission is that embryos of its main vector, the mosquito Aedes aegypti, resist desiccation, surviving several months under dry conditions. The serosal cuticle (SC) contributes to mosquito egg desiccation resistance, but the kinetics of SC secretion during embryogenesis is unknown. It has been argued that mosquito SC contains chitin as one of its components, however conclusive evidence is still missing. Results We observed an abrupt acquisition of desiccation resistance during Ae. aegypti embryogenesis associated with serosal cuticle secretion, occurring at complete germ band extension, between 11 and 13 hours after egglaying. After SC formation embryos are viable on dry for at least several days. The presence of chitin as one of the SC constituents was confirmed through Calcofluor and WGA labeling and chitin quantitation. The Ae. aegypti Chitin Synthase A gene (AaCHS1) possesses two alternatively spliced variants, AaCHS1a and AaCHS1b, differentially expressed during Ae. aegypti embryonic development. It was verified that at the moment of serosal cuticle formation, AaCHS1a is the sole variant specifically expressed. Conclusion In addition to the peritrophic matrix and exoskeleton, these findings confirm chitin is also present in the mosquito serosal cuticle. They also point to the role of the chitinized SC in the desiccation resistance of Ae. aegypti eggs. AaCHS1a expression would be responsible for SC chitin synthesis. With this embryological approach we expect to shed new light regarding this important physiological process related to the Ae. aegypti life cycle. PMID:18789161

The role of novel chitin-like polysaccharides in Alzheimer disease.

PubMed

Castellani, Rudy J; Perry, George; Smith, Mark A

2007-12-01

While controversy over the role of carbohydrates in amyloidosis has existed since the initial recognition of amyloid, current understanding of the role of polysaccharides in the pathogenesis of amyloid deposition of Alzheimer disease and other amyloidoses is limited to studies of glyco-conjugates such as heparin sulfate proteoglycan. We hypothesized that polysaccharides may play a broader role in light of 1) the impaired glucose utilization in Alzheimer disease; 2) the demonstration of amylose in the Alzheimer disease brain; 3) the role of amyloid in Alzheimer disease pathogenesis. Specifically, as with glucose polymers (amyloid), we wanted to explore whether glucosamine polymers such as chitin were being synthesized and deposited as a result of impaired glucose utilization and aberrant hexosamine pathway activation. To this end, using calcofluor histochemistry, we recently demonstrated that amyloid plaques and blood vessels affected by amyloid angiopathy in subjects with sporadic and familial Alzheimer disease elicit chitin-type characteristics. Since chitin is a highly insoluble molecule and a substrate for glycan-protein interactions, chitin-like polysaccharides within the Alzheimer disease brain could provide a scaffolding for amyloid-beta deposition. As such, glucosamine may facilitate the process of amyloidosis, and /or provide neuroprotection in the Alzheimer disease brain.

Cell Wall Remodeling Enzymes Modulate Fungal Cell Wall Elasticity and Osmotic Stress Resistance

PubMed Central

Ene, Iuliana V.; Walker, Louise A.; Schiavone, Marion; Lee, Keunsook K.; Martin-Yken, Hélène; Dague, Etienne; Gow, Neil A. R.; Munro, Carol A.

2015-01-01

ABSTRACT The fungal cell wall confers cell morphology and protection against environmental insults. For fungal pathogens, the cell wall is a key immunological modulator and an ideal therapeutic target. Yeast cell walls possess an inner matrix of interlinked β-glucan and chitin that is thought to provide tensile strength and rigidity. Yeast cells remodel their walls over time in response to environmental change, a process controlled by evolutionarily conserved stress (Hog1) and cell integrity (Mkc1, Cek1) signaling pathways. These mitogen-activated protein kinase (MAPK) pathways modulate cell wall gene expression, leading to the construction of a new, modified cell wall. We show that the cell wall is not rigid but elastic, displaying rapid structural realignments that impact survival following osmotic shock. Lactate-grown Candida albicans cells are more resistant to hyperosmotic shock than glucose-grown cells. We show that this elevated resistance is not dependent on Hog1 or Mkc1 signaling and that most cell death occurs within 10 min of osmotic shock. Sudden decreases in cell volume drive rapid increases in cell wall thickness. The elevated stress resistance of lactate-grown cells correlates with reduced cell wall elasticity, reflected in slower changes in cell volume following hyperosmotic shock. The cell wall elasticity of lactate-grown cells is increased by a triple mutation that inactivates the Crh family of cell wall cross-linking enzymes, leading to increased sensitivity to hyperosmotic shock. Overexpressing Crh family members in glucose-grown cells reduces cell wall elasticity, providing partial protection against hyperosmotic shock. These changes correlate with structural realignment of the cell wall and with the ability of cells to withstand osmotic shock. PMID:26220968

Identification and first insights into the structure and biosynthesis of chitin from the freshwater sponge Spongilla lacustris.

PubMed

Ehrlich, Hermann; Kaluzhnaya, Oksana V; Brunner, Eike; Tsurkan, Mikhail V; Ereskovsky, Alexander; Ilan, Micha; Tabachnick, Konstantin R; Bazhenov, Vasilii V; Paasch, Silvia; Kammer, Martin; Born, René; Stelling, Allison; Galli, Roberta; Belikov, Sergei; Petrova, Olga V; Sivkov, Victor V; Vyalikh, Denis; Hunoldt, Sebastian; Wörheide, Gert

2013-09-01

This work demonstrates that chitin is an important structural component within the skeletal fibers of the freshwater sponge Spongilla lacustris. Using a variety of analytical techniques ((13)C solid state NMR, FT-IR, Raman, NEXAFS, ESI-MS, Morgan-Elson assay and Calcofluor White Staining); we show that this sponge chitin is much closer to α-chitin, known to be present in other animals, than to β-chitin. Genetic analysis confirmed the presence of chitin synthases, which are described for the first time in a sponge. The presence of chitin in both marine (demosponges and hexactinellids) and freshwater sponges indicates that this important structural biopolymer was already present in their common ancestor. Copyright © 2013 Elsevier Inc. All rights reserved.

Infiltration of chitin by protein coacervates defines the squid beak mechanical gradient.

PubMed

Tan, YerPeng; Hoon, Shawn; Guerette, Paul A; Wei, Wei; Ghadban, Ali; Hao, Cai; Miserez, Ali; Waite, J Herbert

2015-07-01

The beak of the jumbo squid Dosidicus gigas is a fascinating example of how seamlessly nature builds with mechanically mismatched materials. A 200-fold stiffness gradient begins in the hydrated chitin of the soft beak base and gradually increases to maximum stiffness in the dehydrated distal rostrum. Here, we combined RNA-Seq and proteomics to show that the beak contains two protein families. One family consists of chitin-binding proteins (DgCBPs) that physically join chitin chains, whereas the other family comprises highly modular histidine-rich proteins (DgHBPs). We propose that DgHBPs play multiple key roles during beak bioprocessing, first by forming concentrated coacervate solutions that diffuse into the DgCBP-chitin scaffold, and second by inducing crosslinking via an abundant GHG sequence motif. These processes generate spatially controlled desolvation, resulting in the impressive biomechanical gradient. Our findings provide novel molecular-scale strategies for designing functional gradient materials.

Cell wall chitosan is necessary for virulence in the opportunistic pathogen Cryptococcus neoformans.

PubMed

Baker, Lorina G; Specht, Charles A; Lodge, Jennifer K

2011-09-01

Cryptococcus neoformans is an opportunistic fungal pathogen that causes meningoencephalitis. Its cell wall is composed of glucans, proteins, chitin, and chitosan. Multiple genetic approaches have defined a chitosan-deficient syndrome that includes slow growth and decreased cell integrity. Here we demonstrate chitosan is necessary for virulence and persistence in the mammalian host.

Knickkopf protein protects and organizes chitin in the newly synthesized insect exoskeleton

PubMed Central

Chaudhari, Sujata S.; Arakane, Yasuyuki; Specht, Charles A.; Moussian, Bernard; Boyle, Daniel L.; Park, Yoonseong; Kramer, Karl J.; Beeman, Richard W.; Muthukrishnan, Subbaratnam

2011-01-01

During each molting cycle of insect development, synthesis of new cuticle occurs concurrently with the partial degradation of the overlying old exoskeleton. Protection of the newly synthesized cuticle from molting fluid enzymes has long been attributed to the presence of an impermeable envelope layer that was thought to serve as a physical barrier, preventing molting fluid enzymes from accessing the new cuticle and thereby ensuring selective degradation of only the old one. In this study, using the red flour beetle, Tribolium castaneum, as a model insect species, we show that an entirely different and unexpected mechanism accounts for the selective action of chitinases and possibly other molting enzymes. The molting fluid enzyme chitinase, which degrades the matrix polysaccharide chitin, is not excluded from the newly synthesized cuticle as previously assumed. Instead, the new cuticle is protected from chitinase action by the T. castaneum Knickkopf (TcKnk) protein. TcKnk colocalizes with chitin in the new cuticle and organizes it into laminae. Down-regulation of TcKnk results in chitinase-dependent loss of chitin, severe molting defects, and lethality at all developmental stages. The conservation of Knickkopf across insect, crustacean, and nematode taxa suggests that its critical roles in the laminar ordering and protection of exoskeletal chitin may be common to all chitinous invertebrates. PMID:21930896

Knickkopf protein protects and organizes chitin in the newly synthesized insect exoskeleton.

PubMed

Chaudhari, Sujata S; Arakane, Yasuyuki; Specht, Charles A; Moussian, Bernard; Boyle, Daniel L; Park, Yoonseong; Kramer, Karl J; Beeman, Richard W; Muthukrishnan, Subbaratnam

2011-10-11

During each molting cycle of insect development, synthesis of new cuticle occurs concurrently with the partial degradation of the overlying old exoskeleton. Protection of the newly synthesized cuticle from molting fluid enzymes has long been attributed to the presence of an impermeable envelope layer that was thought to serve as a physical barrier, preventing molting fluid enzymes from accessing the new cuticle and thereby ensuring selective degradation of only the old one. In this study, using the red flour beetle, Tribolium castaneum, as a model insect species, we show that an entirely different and unexpected mechanism accounts for the selective action of chitinases and possibly other molting enzymes. The molting fluid enzyme chitinase, which degrades the matrix polysaccharide chitin, is not excluded from the newly synthesized cuticle as previously assumed. Instead, the new cuticle is protected from chitinase action by the T. castaneum Knickkopf (TcKnk) protein. TcKnk colocalizes with chitin in the new cuticle and organizes it into laminae. Down-regulation of TcKnk results in chitinase-dependent loss of chitin, severe molting defects, and lethality at all developmental stages. The conservation of Knickkopf across insect, crustacean, and nematode taxa suggests that its critical roles in the laminar ordering and protection of exoskeletal chitin may be common to all chitinous invertebrates.

Acitretin and aloe-emodin loaded chitin nanogel for the treatment of psoriasis.

PubMed

Divya, G; Panonnummal, Rajitha; Gupta, Swati; Jayakumar, R; Sabitha, M

2016-10-01

The present study focuses on the development of an effective topical nanogel formulation of two anti-psoriatic drugs; Acitretin (Act) and Aloe-emodin (AE) using natural polymer chitin. Simple regeneration chemistry was used to prepare Chitin Nanogel Systems (CNGs). The developed control chitin (CNGs) nanogels, acitretin loaded chitin nanogels (ActCNGs) and aloe-emodin loaded chitin nanogels (AECNGs) were characterized by DLS, SEM, FTIR, XRD and TG-DTA. The systems were found to be spherical in shape with a size range of 98±10, 138±8 and 238±6nm having zeta potential values of +28±3, +27±3 and +25±6mV for CNGs, ActCNGs and AECNGs respectively. The in vitro haemolysis assay revealed that all the nanogel systems are blood compatible. The systems exhibited higher swelling and release at acidic pH. The ex vivo skin permeation studies using porcine skin confirmed the higher deposition of the systems at epidermal and dermal layers, which was confirmed further by fluorescent imaging. The in vivo anti-psoriatic activity study using Perry's mouse tail model and skin safety studies confirmed the potential benefit of the system for topical delivery of acitretin and aloe-emodin in psoriasis. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydrogen and oxygen in brine shrimp chitin reflect environmental water and dietary isotopic composition

NASA Astrophysics Data System (ADS)

Nielson, Kristine E.; Bowen, Gabriel J.

2010-03-01

Hydrogen and oxygen isotope ratios of the common structural biopolymer chitin are a potential recorder of ecological and environmental information, but our understanding of the mechanisms of incorporation of H and O from environmental substrates into chitin is limited. We report the results of a set of experiments in which the isotopic compositions of environmental water and diet were varied independently in order to assess the contribution of these variables to the H and O isotopic composition of Artemia franciscana chitin. Hydrogen isotope ratios of chitin were strongly linearly correlated with both food and water, with approximately 26% of the hydrogen signal reflecting food and approximately 38% reflecting water. Oxygen isotopes were also strongly correlated with the isotopic composition of water and food, but whereas 69% of oxygen in chitin exchanged with environmental water, only 10% was derived from food. We propose that these observations reflect the position-specific, partial exchange of H and O atoms with brine shrimp body water during the processes of digestion and chitin biosynthesis. Comparison of culture experiments with a set of natural samples collected from the Great Salt Lake, UT in 2006 shows that, with some exceptions, oxygen isotope compositions of chitin track those of water, whereas hydrogen isotopes vary inversely with those of lake water. The different behavior of the two isotopic systems can be explained in terms of a dietary shift from allochthonous particulate matter with relatively higher δ 2H values in the early spring to autochthonous particulate matter with significantly lower δ 2H values in the late summer to autumn. These results suggest oxygen in chitin may be a valuable proxy for the oxygen isotopic composition of environmental water, whereas hydrogen isotope values from the same molecule may reveal ecological and biogeochemical changes within lakes.

Identification and Characterization of Novel Chitin-Binding Proteins from the Larval Cuticle of Silkworm, Bombyx mori.

PubMed

Dong, Zhaoming; Zhang, Weiwei; Zhang, Yan; Zhang, Xiaolu; Zhao, Ping; Xia, Qingyou

2016-05-06

Cuticle is mainly made of chitin filaments embedded in a matrix of cuticular proteins (CPs). Cuticular chitins have minor differences, whereas CPs are widely variable with respect to their sequences and structures. To understand the molecular basis underlying the mechanical properties of cuticle, it is necessary to know which CPs interact with chitin and how they are assembled into the cuticle structure. In the present study, a chitin-binding assay was performed followed by liquid chromatography-tandem mass spectrometry to identify the extracted proteins from the larval cuticle of silkworm, Bombyx mori. There were 463 proteins identified from the silkworm larval cuticle, 200 of which were recovered in the chitin-binding fraction. A total of 103 proteins were annotated as CPs, which were classified into 11 CP families based on their conserved motifs, including CPR, CPAP, CPT, CPF and CPFL, CPCFC, chitin_bind 3, BmCPH2 homologues, BmCPH9 homologues, BmCPG1 homologues, BmCPG20 homologues, and BmCPG21 homologues. A total of five CP families were newly identified in the chitin-binding fraction, thereby providing new information and insight into the composition, structure, and function of the silkworm larval cuticle.

Chitin-induced T6SS in Vibrio cholerae is dependent on ChiS activation.

PubMed

Chourashi, Rhishita; Das, Suman; Dhar, Debarpan; Okamoto, Keinosuke; Mukhopadhyay, Asish K; Chatterjee, Nabendu Sekhar

2018-05-01

Vibrio cholerae regularly colonizes the chitinous exoskeleton of crustacean shells in the aquatic region. The type 6 secretion system (T6SS) in V. cholerae is an interbacterial killing device. This system is thought to provide a competitive advantage to V. cholerae in a polymicrobial community of the aquatic region under nutrient-poor conditions. V. cholerae chitin sensing is known to be initiated by the activation of a two-component sensor histidine kinase ChiS in the presence of GlcNAc2 (N,N'-diacetylchitobiose) residues generated by the action of chitinases on chitin. It is known that T6SS in V. cholerae is generally induced by chitin. However, the effect of ChiS activation on T6SS is unknown. Here, we found that ChiS inactivation resulted in impaired bacterial killing and reduced expression of T6SS genes. Active ChiS positively affected T6SS-mediated natural transformation in V. cholerae. ChiS depletion or inactivation also resulted in reduced colonization on insoluble chitin surfaces. Therefore, we have shown that V. cholerae colonization on chitinous surfaces activates ChiS, which promotes T6SS-dependent bacterial killing and horizontal gene transfer. We also highlight the importance of chitinases in T6SS upregulation.

Chitin elicits CCL2 from airway epithelial cells and induces CCR2-dependent innate allergic inflammation in the lung

PubMed Central

Roy, René M.; Wüthrich, Marcel; Klein, Bruce S.

2012-01-01

Chitin exposure in the lung induces eosinophilia and alternative activation of macrophages, and is correlated with allergic airway disease. However, the mechanism underlying chitin-induced polarization of macrophages is poorly understood. Here, we show that chitin induces alternative activation of macrophages in vivo, but does not do so directly in vitro. We further show that airway epithelial cells bind chitin in vitro and produce CCL2 in response to chitin both in vitro and in vivo. Supernatants of chitin exposed epithelial cells promoted alternative activation of macrophages in vitro, whereas antibody neutralization of CCL2 in the supernate abolished the alternative activation of macrophages. CCL2 acted redundantly in vivo, but mice lacking the CCL2 receptor, CCR2, showed impaired alternative activation of macrophages in response to chitin, as measured by arginase I, CCL17 and CCL22 expression. Furthermore, CCR2KO mice exposed to chitin had diminished ROS products in the lung, blunted eosinophil and monocyte recruitment, and impaired eosinophil functions as measured by expression of CCL5, IL13 and CCL11. Thus, airway epithelial cells secrete CCL2 in response to chitin and CCR2 signaling mediates chitin-induced alternative activation of macrophages and allergic inflammation in vivo. PMID:22851704

Isolation and identification of chitin in the black coral Parantipathes larix (Anthozoa: Cnidaria).

PubMed

Bo, Marzia; Bavestrello, Giorgio; Kurek, Denis; Paasch, Silvia; Brunner, Eike; Born, René; Galli, Roberta; Stelling, Allison L; Sivkov, Viktor N; Petrova, Olga V; Vyalikh, Denis; Kummer, Kurt; Molodtsov, Serguei L; Nowak, Dorota; Nowak, Jakub; Ehrlich, Hermann

2012-01-01

Until now, there is a lack of knowledge about the presence of chitin in numerous representatives of corals (Cnidaria). However, investigations concerning the chitin-based skeletal organization in different coral taxa are significant from biochemical, structural, developmental, ecological and evolutionary points of view. In this paper, we present a thorough screening for the presence of chitin within the skeletal formations of a poorly investigated Mediterranean black coral, Parantipathes larix (Esper, 1792), as a typical representative of the Schizopathidae family. Using a wide array variety of techniques ((13)C solid state NMR, Fourier transform infrared (FTIR), Raman, NEXAFS, Morgan-Elson assay and Calcofluor White Staining), we unambiguously show for the first time that chitin is an important component within the skeletal stalks as well as pinnules of this coral. Copyright © 2012 Elsevier B.V. All rights reserved.

Studies on the chitin/chitosan binding properties of six cuticular proteins analogous to peritrophin 3 from Bombyx mori.

PubMed

Qu, M; Ren, Y; Liu, Y; Yang, Q

2017-08-01

Chitin deacetylation is required to make the cuticle rigid and compact through chitin chain crosslinking. Thus it is presumed that specialized proteins are required to bind deacetylated chitin chains together. However, deacetylated-chitin binding proteins have not ever been reported. In a previous work, six cuticular proteins analogous to peritrophin 3 (CPAP3s) were found to be abundant in the moulting fluid of Bombyx mori. In this study, these BmCPAP3s (BmCPAP3-A1, BmCPAP3-A2, BmCPAP3-B, BmCPAP3-C, BmCPAP3-D1 and BmCPAP3-D2) were cloned and expressed in Escherichia coli and purified using metal-chelating affinity chromatography. Their binding activities demonstrated that although all of the BmCPAP3s showed similar binding abilities toward crystalline chitin and colloidal chitin, they differed in their affinities toward partially and fully deacetylated chitin. Amongst them, BmCPAP3-D1 exhibited the highest binding activity toward deacetylated chitin. The gene expression pattern of BmCPAP3-D1 was similar to BmCPAP3-A1 and BmCPAP3-C at most stages except that it was dramatically upregulated at the beginning of the pupa to adult transition stage. This work is the first report of a chitin-binding protein, BmCPAP3-D1, which exhibits high binding affinity to deacetylated chitin. © 2017 The Royal Entomological Society.

The role of chitin, chitinases, and chitinase-like proteins in pediatric lung diseases.

PubMed

Mack, Ines; Hector, Andreas; Ballbach, Marlene; Kohlhäufl, Julius; Fuchs, Katharina J; Weber, Alexander; Mall, Marcus A; Hartl, Dominik

2015-12-01

Chitin, after cellulose, the second most abundant biopolymer on earth, is a key component of insects, fungi, and house-dust mites. Lower life forms are endowed with chitinases to defend themselves against chitin-bearing pathogens. Unexpectedly, humans were also found to express chitinases as well as chitinase-like proteins that modulate immune responses. Particularly, increased levels of the chitinase-like protein YKL-40 have been associated with severe asthma, cystic fibrosis, and other inflammatory disease conditions. Here, we summarize and discuss the potential role of chitin, chitinases, and chitinase-like proteins in pediatric lung diseases.

β-1,3-Glucan, Which Can Be Targeted by Drugs, Forms a Trabecular Scaffold in the Oocyst Walls of Toxoplasma and Eimeria

PubMed Central

Bushkin, G. Guy; Motari, Edwin; Magnelli, Paula; Gubbels, Marc-Jan; Dubey, Jitender P.; Miska, Katarzyna B.; Bullitt, Esther; Costello, Catherine E.; Robbins, Phillips W.; Samuelson, John

2012-01-01

ABSTRACT The walls of infectious pathogens, which are essential for transmission, pathogenesis, and diagnosis, contain sugar polymers that are defining structural features, e.g., β-1,3-glucan and chitin in fungi, chitin in Entamoeba cysts, β-1,3-GalNAc in Giardia cysts, and peptidoglycans in bacteria. The goal here was to determine in which of three walled forms of Toxoplasma gondii (oocyst, sporocyst, or tissue cyst) is β-1,3-glucan, the product of glucan synthases and glucan hydrolases predicted by whole-genome sequences of the parasite. The three most important discoveries were as follows. (i) β-1,3-glucan is present in oocyst walls of Toxoplasma and Eimeria (a chicken parasite that is a model for intestinal stages of Toxoplasma) but is absent from sporocyst and tissue cyst walls. (ii) Fibrils of β-1,3-glucan are part of a trabecular scaffold in the inner layer of the oocyst wall, which also includes a glucan hydrolase that has a novel glucan-binding domain. (iii) Echinocandins, which target the glucan synthase and kill fungi, arrest development of the Eimeria oocyst wall and prevent release of the parasites into the intestinal lumen. In summary, β-1,3-glucan, which can be targeted by drugs, is an important component of oocyst walls of Toxoplasma but is not a component of sporocyst and tissue cyst walls. PMID:23015739

Bioconversion of Chitin to Bioactive Chitooligosaccharides: Amelioration and Coastal Pollution Reduction by Microbial Resources.

PubMed

Kumar, Manish; Brar, Amandeep; Vivekanand, V; Pareek, Nidhi

2018-04-10

Chitin-metabolizing products are of high industrial relevance in current scenario due to their wide biological applications, relatively lower cost, greater abundance, and sustainable supply. Chitooligosaccharides have remarkably wide spectrum of applications in therapeutics such as antitumor agents, immunomodulators, drug delivery, gene therapy, wound dressings, as chitinase inhibitors to prevent malaria. Hypocholesterolemic and antimicrobial activities of chitooligosaccharides make them a molecule of choice for food industry, and their functional profile depends on the physicochemical characteristics. Recently, chitin-based nanomaterials are also gaining tremendous importance in biomedical and agricultural applications. Crystallinity and insolubility of chitin imposes a major hurdle in the way of polymer utilization. Chemical production processes are known to produce chitooligosaccharides with variable degree of polymerization and properties along with ecological concerns. Biological production routes mainly involve chitinases, chitosanases, and chitin-binding proteins. Development of bio-catalytic production routes for chitin will not only enhance the production of commercially viable chitooligosaccharides with defined molecular properties but will also provide a means to combat marine pollution with value addition.

Increased chitin biosynthesis contributes to the resistance of Penicillium polonicum against the antifungal protein PgAFP.

PubMed

Delgado, Josué; Owens, Rebecca A; Doyle, Sean; Asensio, Miguel A; Núñez, Félix

2016-01-01

Antifungal proteins from molds have been proposed as a valuable tool against unwanted molds, but the resistance of some fungi limits their use. Resistance to antimicrobial peptides has been suggested to be due to lack of interaction with the mold or to a successful response. The antifungal protein PgAFP produced by Penicillium chrysogenum inhibits the growth of various ascomycetes, but not Penicillium polonicum. To study the basis for resistance to this antifungal protein, localization of PgAFP and metabolic, structural, and morphological changes were investigated in P. polonicum. PgAFP bound the outer layer of P. polonicum but not regenerated chitin, suggesting an interaction with specific molecules. Comparative two-dimensional gel electrophoresis (2D-PAGE) and comparative quantitative proteomics revealed changes in the relative abundance of several proteins from ribosome, spliceosome, metabolic, and biosynthesis of secondary metabolite pathways. The proteome changes and an altered permeability reveal an active reaction of P. polonicum to PgAFP. The successful response of the resistant mold seems to be based on the higher abundance of protein Rho GTPase Rho1 that would lead to the increased chitin deposition via cell wall integrity (CWI) signaling pathway. Thus, combined treatment with chitinases could provide a complementary means to combat resistance to antifungal proteins.

First Report on Chitin in a Non-Verongiid Marine Demosponge: The Mycale euplectellioides Case.

PubMed

Żółtowska-Aksamitowska, Sonia; Shaala, Lamiaa A; Youssef, Diaa T A; Elhady, Sameh S; Tsurkan, Mikhail V; Petrenko, Iaroslav; Wysokowski, Marcin; Tabachnick, Konstantin; Meissner, Heike; Ivanenko, Viatcheslav N; Bechmann, Nicole; Joseph, Yvonne; Jesionowski, Teofil; Ehrlich, Hermann

2018-02-20

Sponges (Porifera) are recognized as aquatic multicellular organisms which developed an effective biochemical pathway over millions of years of evolution to produce both biologically active secondary metabolites and biopolymer-based skeletal structures. Among marine demosponges, only representatives of the Verongiida order are known to synthetize biologically active substances as well as skeletons made of structural polysaccharide chitin. The unique three-dimensional (3D) architecture of such chitinous skeletons opens the widow for their recent applications as adsorbents, as well as scaffolds for tissue engineering and biomimetics. This study has the ambitious goal of monitoring other orders beyond Verongiida demosponges and finding alternative sources of naturally prestructured chitinous scaffolds; especially in those demosponge species which can be cultivated at large scales using marine farming conditions. Special attention has been paid to the demosponge Mycale euplectellioides (Heteroscleromorpha: Poecilosclerida: Mycalidae) collected in the Red Sea. For the first time, we present here a detailed study of the isolation of chitin from the skeleton of this sponge, as well as its identification using diverse bioanalytical tools. Calcofluor white staining, Fourier-transform Infrared Spcetcroscopy (FTIR), electrospray ionization mass spectrometry (ESI-MS), scanning electron microscopy (SEM), and fluorescence microscopy, as well as a chitinase digestion assay were applied in order to confirm with strong evidence the finding of a-chitin in the skeleton of M. euplectellioides . We suggest that the discovery of chitin within representatives of the Mycale genus is a promising step in their evaluation of these globally distributed sponges as new renewable sources for both biologically active metabolites and chitin, which are of prospective use for pharmacology and biomaterials oriented biomedicine, respectively.

First Report on Chitin in a Non-Verongiid Marine Demosponge: The Mycale euplectellioides Case

PubMed Central

Żółtowska-Aksamitowska, Sonia; Petrenko, Iaroslav; Wysokowski, Marcin; Tabachnick, Konstantin; Meissner, Heike; Jesionowski, Teofil; Ehrlich, Hermann

2018-01-01

Sponges (Porifera) are recognized as aquatic multicellular organisms which developed an effective biochemical pathway over millions of years of evolution to produce both biologically active secondary metabolites and biopolymer-based skeletal structures. Among marine demosponges, only representatives of the Verongiida order are known to synthetize biologically active substances as well as skeletons made of structural polysaccharide chitin. The unique three-dimensional (3D) architecture of such chitinous skeletons opens the widow for their recent applications as adsorbents, as well as scaffolds for tissue engineering and biomimetics. This study has the ambitious goal of monitoring other orders beyond Verongiida demosponges and finding alternative sources of naturally prestructured chitinous scaffolds; especially in those demosponge species which can be cultivated at large scales using marine farming conditions. Special attention has been paid to the demosponge Mycale euplectellioides (Heteroscleromorpha: Poecilosclerida: Mycalidae) collected in the Red Sea. For the first time, we present here a detailed study of the isolation of chitin from the skeleton of this sponge, as well as its identification using diverse bioanalytical tools. Calcofluor white staining, Fourier-transform Infrared Spcetcroscopy (FTIR), electrospray ionization mass spectrometry (ESI-MS), scanning electron microscopy (SEM), and fluorescence microscopy, as well as a chitinase digestion assay were applied in order to confirm with strong evidence the finding of a-chitin in the skeleton of M. euplectellioides. We suggest that the discovery of chitin within representatives of the Mycale genus is a promising step in their evaluation of these globally distributed sponges as new renewable sources for both biologically active metabolites and chitin, which are of prospective use for pharmacology and biomaterials oriented biomedicine, respectively. PMID:29461501

Chitinase Chi1 from Myceliophthora thermophila C1, a Thermostable Enzyme for Chitin and Chitosan Depolymerization

PubMed Central

2018-01-01

A thermostable Chitinase Chi1 from Myceliophthora thermophila C1 was homologously produced and characterized. Chitinase Chi1 shows high thermostability at 40 °C (>140 h 90% activity), 50 °C (>168 h 90% activity), and 55 °C (half-life 48 h). Chitinase Chi1 has broad substrate specificity and converts chitin, chitosan, modified chitosan, and chitin oligosaccharides. The activity of Chitinase Chi1 is strongly affected by the degree of deacetylation (DDA), molecular weight (Mw), and side chain modification of chitosan. Chitinase Chi1 releases mainly (GlcNAc)2 from insoluble chitin and chito-oligosaccharides with a polymerization degree (DP) ranging from 2 to 12 from chitosan, in a processive way. Chitinase Chi1 shows higher activity toward chitin oligosaccharides (GlcNAc)4–6 than toward (GlcNAc)3 and is inactive for (GlcNAc)2. During hydrolysis, oligosaccharides bind at subsites −2 to +2 in the enzyme’s active site. Chitinase Chi1 can be used for chitin valorisation and for production of chitin- and chito-oligosaccharides at industrial scale. PMID:29359934

Chitinase Chi1 from Myceliophthora thermophila C1, a Thermostable Enzyme for Chitin and Chitosan Depolymerization.

PubMed

Krolicka, Malgorzata; Hinz, Sandra W A; Koetsier, Martijn J; Joosten, Rob; Eggink, Gerrit; van den Broek, Lambertus A M; Boeriu, Carmen G

2018-02-21

A thermostable Chitinase Chi1 from Myceliophthora thermophila C1 was homologously produced and characterized. Chitinase Chi1 shows high thermostability at 40 °C (>140 h 90% activity), 50 °C (>168 h 90% activity), and 55 °C (half-life 48 h). Chitinase Chi1 has broad substrate specificity and converts chitin, chitosan, modified chitosan, and chitin oligosaccharides. The activity of Chitinase Chi1 is strongly affected by the degree of deacetylation (DDA), molecular weight (Mw), and side chain modification of chitosan. Chitinase Chi1 releases mainly (GlcNAc) 2 from insoluble chitin and chito-oligosaccharides with a polymerization degree (DP) ranging from 2 to 12 from chitosan, in a processive way. Chitinase Chi1 shows higher activity toward chitin oligosaccharides (GlcNAc) 4-6 than toward (GlcNAc) 3 and is inactive for (GlcNAc) 2 . During hydrolysis, oligosaccharides bind at subsites -2 to +2 in the enzyme's active site. Chitinase Chi1 can be used for chitin valorisation and for production of chitin- and chito-oligosaccharides at industrial scale.

Cell Wall Chitosan Is Necessary for Virulence in the Opportunistic Pathogen Cryptococcus neoformans ▿

PubMed Central

Baker, Lorina G.; Specht, Charles A.; Lodge, Jennifer K.

2011-01-01

Cryptococcus neoformans is an opportunistic fungal pathogen that causes meningoencephalitis. Its cell wall is composed of glucans, proteins, chitin, and chitosan. Multiple genetic approaches have defined a chitosan-deficient syndrome that includes slow growth and decreased cell integrity. Here we demonstrate chitosan is necessary for virulence and persistence in the mammalian host. PMID:21784998

Crystal defects induced by chitin and chitinolytic enzymes in the prismatic layer of Pinctada fucata.

PubMed

Kintsu, Hiroyuki; Okumura, Taiga; Negishi, Lumi; Ifuku, Shinsuke; Kogure, Toshihiro; Sakuda, Shohei; Suzuki, Michio

2017-07-22

Biomineralization, in which organisms create biogenic hard tissues, with hardness or flexibility enhanced by organic-inorganic interaction is an interesting and attractive focus for application of biomimetic functional materials. Calcites in the prismatic layer of Pinctada fucata are tougher than abiotic calcites due to small crystal defects. However, the molecular mechanism of the defect formation remains unclear. Here, chitin and two chitinolytic enzymes, chitinase and chitobiase, were identified as organic matrices related to for the formation of small crystal defects in the prismatic layer. Experiments with a chitinase inhibitor in vivo showed chitinase is necessary to form the prismatic layer. Analysis of calcite crystals, which were synthesized in a chitin hydrogel treated with chitinolytic enzymes, by electron microscopy and X-ray diffraction showed that crystal defects became larger as chitin was more degraded. These results suggest that interactions between chitin and calcium carbonate increase as chitin is thinner. Copyright © 2017. Published by Elsevier Inc.

AFM PeakForce QNM mode: Evidencing nanometre-scale mechanical properties of chitin-silica hybrid nanocomposites.

PubMed

Smolyakov, G; Pruvost, S; Cardoso, L; Alonso, B; Belamie, E; Duchet-Rumeau, J

2016-10-20

PeakForce Quantitative Nanomechanical Mapping (QNM) AFM mode was used to explore the mechanical properties of textured chitin-silica hybrid films at the nanoscale. The influence of the force applied by the tip on the sample surface was studied for standard homogeneous samples, for chitin nanorods and for chitin-silica hybrid nanocomposites. Thick films of superimposed chitin nanorods showed a monotonous increase of DMT modulus (based on the Derjaguin-Muller-Toporov model) owing to an increase in modulus at the interface between nanorods due to geometrical constraints of the AFM acquisition. A similar variation of DMT modulus was obtained for chitin-silica hybrid thick films related to mechanical strengthening induced by the presence of silica. This work revealed the role of the organic-inorganic interface, at the nanoscale, in the mechanical behaviour of textured materials using PeakForce QNM mode, with optimized analysis conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chiral nematic self-assembly of minimally surface damaged chitin nanofibrils and its load bearing functions

NASA Astrophysics Data System (ADS)

Oh, Dongyeop X.; Cha, Yun Jeong; Nguyen, Hoang-Linh; Je, Hwa Heon; Jho, Yong Seok; Hwang, Dong Soo; Yoon, Dong Ki

2016-03-01

Chitin is one of the most abundant biomaterials in nature, with 1010 tons produced annually as hierarchically organized nanofibril fillers to reinforce the exoskeletons of arthropods. This green and cheap biomaterial has attracted great attention due to its potential application to reinforce biomedical materials. Despite that, its practical use is limited since the extraction of chitin nanofibrils requires surface modification involving harsh chemical treatments, leading to difficulties in reproducing their natural prototypal hierarchical structure, i.e. chiral nematic phase. Here, we develop a chemical etching-free approach using calcium ions, called “natural way”, to disintegrate the chitin nanofibrils while keeping the essential moiety for the self-assembly, ultimately resulting in the reproduction of chitin’s natural chiral structure in a polymeric matrix. This chiral chitin nanostructure exceptionally toughens the composite. Our resultant chiral nematic phase of chitin materials can contribute to the understanding and use of the reinforcing strategy in nature.

Chiral nematic self-assembly of minimally surface damaged chitin nanofibrils and its load bearing functions

PubMed Central

Oh, Dongyeop X.; Cha, Yun Jeong; Nguyen, Hoang-Linh; Je, Hwa Heon; Jho, Yong Seok; Hwang, Dong Soo; Yoon, Dong Ki

2016-01-01

Chitin is one of the most abundant biomaterials in nature, with 1010 tons produced annually as hierarchically organized nanofibril fillers to reinforce the exoskeletons of arthropods. This green and cheap biomaterial has attracted great attention due to its potential application to reinforce biomedical materials. Despite that, its practical use is limited since the extraction of chitin nanofibrils requires surface modification involving harsh chemical treatments, leading to difficulties in reproducing their natural prototypal hierarchical structure, i.e. chiral nematic phase. Here, we develop a chemical etching-free approach using calcium ions, called “natural way”, to disintegrate the chitin nanofibrils while keeping the essential moiety for the self-assembly, ultimately resulting in the reproduction of chitin’s natural chiral structure in a polymeric matrix. This chiral chitin nanostructure exceptionally toughens the composite. Our resultant chiral nematic phase of chitin materials can contribute to the understanding and use of the reinforcing strategy in nature. PMID:26988392

Candida albicans Chitin Increases Arginase-1 Activity in Human Macrophages, with an Impact on Macrophage Antimicrobial Functions

PubMed Central

MacCallum, Donna M.; Brown, Gordon D.

2017-01-01

ABSTRACT   The opportunistic human fungal pathogen Candida albicans can cause a variety of diseases, ranging from superficial mucosal infections to life-threatening systemic infections. Phagocytic cells of the innate immune response, such as neutrophils and macrophages, are important first-line responders to an infection and generate reactive oxygen and nitrogen species as part of their protective antimicrobial response. During an infection, host cells generate nitric oxide through the enzyme inducible nitric oxide synthase (iNOS) to kill the invading pathogen. Inside the phagocyte, iNOS competes with the enzyme arginase-1 for a common substrate, the amino acid l-arginine. Several pathogenic species, including bacteria and parasitic protozoans, actively modulate the production of nitric oxide by inducing their own arginases or the host’s arginase activity to prevent the conversion of l-arginine to nitric oxide. We report here that C. albicans blocks nitric oxide production in human-monocyte-derived macrophages by induction of host arginase activity. We further determined that purified chitin (a fungal cell wall polysaccharide) and increased chitin exposure at the fungal cell wall surface induces this host arginase activity. Blocking the C. albicans-induced arginase activity with the arginase-specific substrate inhibitor Nω-hydroxy-nor-arginine (nor-NOHA) or the chitinase inhibitor bisdionin F restored nitric oxide production and increased the efficiency of fungal killing. Moreover, we determined that C. albicans influences macrophage polarization from a classically activated phenotype toward an alternatively activated phenotype, thereby reducing antimicrobial functions and mediating fungal survival. Therefore, C. albicans modulates l-arginine metabolism in macrophages during an infection, potentiating its own survival. PMID:28119468

Rim Pathway-Mediated Alterations in the Fungal Cell Wall Influence Immune Recognition and Inflammation.

PubMed

Ost, Kyla S; Esher, Shannon K; Leopold Wager, Chrissy M; Walker, Louise; Wagener, Jeanette; Munro, Carol; Wormley, Floyd L; Alspaugh, J Andrew

2017-01-31

Compared to other fungal pathogens, Cryptococcus neoformans is particularly adept at avoiding detection by innate immune cells. To explore fungal cellular features involved in immune avoidance, we characterized cell surface changes of the C. neoformans rim101Δ mutant, a strain that fails to organize and shield immunogenic epitopes from host detection. These cell surface changes are associated with an exaggerated, detrimental inflammatory response in mouse models of infection. We determined that the disorganized strain rim101Δ cell wall increases macrophage detection in a contact-dependent manner. Using biochemical and microscopy methods, we demonstrated that the rim101Δ strain shows a modest increase in the levels of both cell wall chitin and chitosan but that it shows a more dramatic increase in chito-oligomer exposure, as measured by wheat germ agglutinin staining. We also created a series of mutants with various levels of cell wall wheat germ agglutinin staining, and we demonstrated that the staining intensity correlates with the degree of macrophage activation in response to each strain. To explore the host receptors responsible for recognizing the rim101Δ mutant, we determined that both the MyD88 and CARD9 innate immune signaling proteins are involved. Finally, we characterized the immune response to the rim101Δ mutant in vivo, documenting a dramatic and sustained increase in Th1 and Th17 cytokine responses. These results suggest that the Rim101 transcription factor actively regulates the C. neoformans cell wall to prevent the exposure of immune stimulatory molecules within the host. These studies further explored the ways in which immune cells detect C. neoformans and other fungal pathogens by mechanisms that include sensing N-acetylglucosamine-containing structures, such as chitin and chitosan. Infectious microorganisms have developed many ways to avoid recognition by the host immune system. For example, pathogenic fungi alter their cell surfaces to

The N-Linked Outer Chain Mannans and the Dfg5p and Dcw1p Endo-α-1,6-Mannanases Are Needed for Incorporation of Candida albicans Glycoproteins into the Cell Wall

PubMed Central

Ao, Jie; Chinnici, Jennifer L.; Maddi, Abhiram

2015-01-01

A biochemical pathway for the incorporation of cell wall protein into the cell wall of Neurospora crassa was recently proposed. In this pathway, the DFG-5 and DCW-1 endo-α-1,6-mannanases function to covalently cross-link cell wall protein-associated N-linked galactomannans, which are structurally related to the yeast outer chain mannans, into the cell wall glucan-chitin matrix. In this report, we demonstrate that the mannosyltransferase enzyme Och1p, which is needed for the synthesis of the N-linked outer chain mannan, is essential for the incorporation of cell wall glycoproteins into the Candida albicans cell wall. Using endoglycosidases, we show that C. albicans cell wall proteins are cross-linked into the cell wall via their N-linked outer chain mannans. We further demonstrate that the Dfg5p and Dcw1p α-1,6-mannanases are needed for the incorporation of cell wall glycoproteins into the C. albicans cell wall. Our results support the hypothesis that the Dfg5p and Dcw1p α-1,6-mannanases incorporate cell wall glycoproteins into the C. albicans cell wall by cross-linking outer chain mannans into the cell wall glucan-chitin matrix. PMID:26048011

Biosorption of gold from computer microprocessor leachate solutions using chitin.

PubMed

Côrtes, Letícia N; Tanabe, Eduardo H; Bertuol, Daniel A; Dotto, Guilherme L

2015-11-01

The biosorption of gold from discarded computer microprocessor (DCM) leachate solutions was studied using chitin as a biosorbent. The DCM components were leached with thiourea solutions, and two procedures were tested for recovery of gold from the leachates: (1) biosorption and (2) precipitation followed by biosorption. For each procedure, the biosorption was evaluated considering kinetic, equilibrium, and thermodynamic aspects. The general order model was able to represent the kinetic behavior, and the equilibrium was well represented by the BET model. The maximum biosorption capacities were around 35 mg g(-1) for both procedures. The biosorption of gold on chitin was a spontaneous, favorable, and exothermic process. It was found that precipitation followed by biosorption resulted in the best gold recovery, because other species were removed from the leachate solution in the precipitation step. This method enabled about 80% of the gold to be recovered, using 20 g L(-1) of chitin at 298 K for 4 h. Copyright © 2015 Elsevier Ltd. All rights reserved.

Radiation absorbed dose to bladder walls from positron emitters in the bladder content.

PubMed

Powell, G F; Chen, C T

1987-01-01

A method to calculate absorbed doses at depths in the walls of a static spherical bladder from a positron emitter in the bladder content has been developed. The beta ray dose component is calculated for a spherical model by employing the solutions to the integration of Loevinger and Bochkarev point source functions over line segments and a line segment source array technique. The gamma ray dose is determined using the specific gamma ray constant. As an example, absorbed radiation doses to the bladder walls from F-18 in the bladder content are presented for static spherical bladder models having radii of 2.0 and 3.5 cm, respectively. Experiments with ultra-thin thermoluminescent dosimeters (TLD's) were performed to verify the results of the calculations. Good agreement between TLD measurements and calculations was obtained.

Paradoxical Growth of Candida albicans in the Presence of Caspofungin Is Associated with Multiple Cell Wall Rearrangements and Decreased Virulence

PubMed Central

Rueda, Cristina; Cuenca-Estrella, Manuel

2014-01-01

In the last decade, echinocandins have emerged as an important family of antifungal drugs because of their fungicidal activity against Candida spp. Echinocandins inhibit the enzyme β-1,3-d-glucan synthase, encoded by the FKS genes, and resistance to echinocandins is associated with mutations in this gene. In addition, echinocandin exposure can produce paradoxical growth, defined as the ability to grow at high antifungal concentrations but not at intermediate concentrations. In this work, we have demonstrated that paradoxical growth of Candida albicans in the presence of caspofungin is not due to antifungal degradation or instability. Media with high caspofungin concentrations recovered from wells where C. albicans showed paradoxical growth inhibited the growth of a Candida krusei reference strain. Cells exhibiting paradoxical growth at high caspofungin concentrations showed morphological changes such as enlarged size, abnormal septa, and absence of filamentation. Chitin content increased from the MIC to high caspofungin concentrations. Despite the high chitin levels, around 23% of cells died after treatment with caspofungin, indicating that chitin is required but not sufficient to protect the cells from the fungicidal effect of caspofungin. Moreover, we found that after paradoxical growth, β-1,3-glucan was exposed at the cell wall surface. Cells grown at high caspofungin concentrations had decreased virulence in the invertebrate host Galleria mellonella. Cells grown at high caspofungin concentrations also induced a proinflammatory response in murine macrophages compared to control cells. Our work highlights important aspects about fungal adaptation to caspofungin, and although this adaptation is associated with reduced virulence, the clinical implications remain to be elucidated. PMID:24295973

Optimization of conditions for isolation of high quality chitin from shrimp processing raw byproducts using response surface methodology and its characterization.

PubMed

Nidheesh, T; Suresh, P V

2015-06-01

Chitin is one of the most abundant bioactive biopolymer on earth. It is commercially extracted from seafood processing crustacean shell byproducts by harsh thermochemical treatments. The extraction conditions, the source and pretreatment of raw material significantly affect its quality and bioactivity. In this investigation response surface methodology (RSM) has been applied to optimize and evaluate the interaction of variables for extraction of high quality chitin from shrimp processing raw byproducts. Variables such as, concentration of HCl (%, v/v) 4.5 (for wet) and 4.9 (for dry), reaction time 3 h, solid liquid ratio of HCl (w/v) 1:5.5 (for wet) and 1:7.9 (for dry) with two treatments achieved >98 % demineralization of shrimp byproduct. Variables such as, concentration of NaOH 3.6 % (w/v), reaction time 2.5 h, temperature 69.0 ± 1 °C, solid liquid ratio of NaOH 7.4 (w/v) and two treatments accomplished >98 % deproteinization of demineralized byproducts. Significant (p ≤ 0.05-0.001) interactive effects were observed between different variables. Chitin obtained in these conditions had residual content (%, w/w) of ash <0.4 and protein <0.8 and the degree of N-acetylation was >93 % with purity of >98 %. In conclusion, the optimized conditions by RSM can be applied for large scale preparation of high quality chitin from raw shrimp byproduct.

Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition.

PubMed

Esher, Shannon K; Ost, Kyla S; Kohlbrenner, Maria A; Pianalto, Kaila M; Telzrow, Calla L; Campuzano, Althea; Nichols, Connie B; Munro, Carol; Wormley, Floyd L; Alspaugh, J Andrew

2018-06-01

The human fungal pathogen, Cryptococcus neoformans, dramatically alters its cell wall, both in size and composition, upon entering the host. This cell wall remodeling is essential for host immune avoidance by this pathogen. In a genetic screen for mutants with changes in their cell wall, we identified a novel protein, Mar1, that controls cell wall organization and immune evasion. Through phenotypic studies of a loss-of-function strain, we have demonstrated that the mar1Δ mutant has an aberrant cell surface and a defect in polysaccharide capsule attachment, resulting in attenuated virulence. Furthermore, the mar1Δ mutant displays increased staining for exposed cell wall chitin and chitosan when the cells are grown in host-like tissue culture conditions. However, HPLC analysis of whole cell walls and RT-PCR analysis of cell wall synthase genes demonstrated that this increased chitin exposure is likely due to decreased levels of glucans and mannans in the outer cell wall layers. We observed that the Mar1 protein differentially localizes to cellular membranes in a condition dependent manner, and we have further shown that the mar1Δ mutant displays defects in intracellular trafficking, resulting in a mislocalization of the β-glucan synthase catalytic subunit, Fks1. These cell surface changes influence the host-pathogen interaction, resulting in increased macrophage activation to microbial challenge in vitro. We established that several host innate immune signaling proteins are required for the observed macrophage activation, including the Card9 and MyD88 adaptor proteins, as well as the Dectin-1 and TLR2 pattern recognition receptors. These studies explore novel mechanisms by which a microbial pathogen regulates its cell surface in response to the host, as well as how dysregulation of this adaptive response leads to defective immune avoidance.

Modification of Chitin with Kraft Lignin and Development of New Biosorbents for Removal of Cadmium(II) and Nickel(II) Ions

PubMed Central

Wysokowski, Marcin; Klapiszewski, Łukasz; Moszyński, Dariusz; Bartczak, Przemysław; Szatkowski, Tomasz; Majchrzak, Izabela; Siwińska-Stefańska, Katarzyna; Bazhenov, Vasilii V.; Jesionowski, Teofil

2014-01-01

Novel, functional materials based on chitin of marine origin and lignin were prepared. The synthesized materials were subjected to physicochemical, dispersive-morphological and electrokinetic analysis. The results confirm the effectiveness of the proposed method of synthesis of functional chitin/lignin materials. Mechanism of chitin modification by lignin is based on formation of hydrogen bonds between chitin and lignin. Additionally, the chitin/lignin materials were studied from the perspective of waste water treatment. The synthetic method presented in this work shows an attractive and facile route for producing low-cost chitin/lignin biosorbents with high efficiency of nickel and cadmium adsorption (88.0% and 98.4%, respectively). The discovery of this facile method of synthesis of functional chitin/lignin materials will also have a significant impact on the problematic issue of the utilization of chitinous waste from the seafood industry, as well as lignin by-products from the pulp and paper industry. PMID:24727394

The mitogen-activated protein kinase GlSlt2 regulates fungal growth, fruiting body development, cell wall integrity, oxidative stress and ganoderic acid biosynthesis in Ganoderma lucidum.

PubMed

Zhang, Guang; Sun, Zehua; Ren, Ang; Shi, Liang; Shi, Dengke; Li, Xiongbiao; Zhao, Mingwen

2017-07-01

The mitogen-activated protein kinases (MAPKs) are crucial signaling instruments in eukaryotes that play key roles in regulating fungal growth, development, and secondary metabolism and in adapting to the environment. In this study, we characterized an Slt2-type MAPK in Ganoderma lucidum, GlSlt2, which was transcriptionally induced during the primordium and fruiting body stages. RNA interference was used to examine the function of GlSlt2. Knockdown of GlSlt2 caused defects in growth and increased hyphal branching as well as hypersensitivity to cell wall-disturbing substances. Consistently, the chitin and β-1,3-d-glucan contents and the expression of cell wall biosynthesis genes were decreased and down-regulated, respectively, in GlSlt2 knockdown strains compared with those in the wild type (WT). In addition, no primordium or fruiting body could be observed in GlSlt2 knockdown strains. Furthermore, the intracellular reactive oxygen species (ROS) content and ganoderic acid biosynthesis also decreased in GlSlt2 knockdown strains. Addition of H 2 O 2 could recover the decreased ganoderic acid content in GlSlt2 knockdown strains, indicating that GlSlt2 might regulate ganoderic acid biosynthesis via the intracellular ROS level. Overall, GlSlt2 is involved in hyphal growth, fruiting body development, cell wall integrity, oxidative stress and ganoderic acid biosynthesis in G. lucidum. Copyright © 2017 Elsevier Inc. All rights reserved.

Sesquiterpene furan compound CJ-01, a novel chitin synthase 2 inhibitor from Chloranthus japonicus SIEB.

PubMed

Yim, Nam Hui; Hwang, Eui Il; Yun, Bong Sik; Park, Ki Duk; Moon, Jae Sun; Lee, Sang Han; Sung, Nack Do; Kim, Sung Uk

2008-05-01

A novel sesquiterpene furan compound CJ-01 was isolated from the methanol extract of the whole plant of Chloranthus japonicus SIEB. by monitoring the inhibitory activity of chitin synthase 2 from Saccharomyces cerevisiae. Based on spectroscopic analysis, the structure of compound CJ-01 was determined as 3,4,8a-trimethyl-4a,7,8,8a-tetrahydro-4a-naphto[2,3-b]furan-9-one. The compound inhibited chitin synthase 2 of Saccharomyces cerevisiae in a dose-dependent manner with an IC50 of 39.6 microg/ml, whereas it exhibited no inhibitory activities against chitin synthase 1 and 3 of S. cerevisiae up to 280 microg/ml. CJ-01 has 1.7-fold stronger inhibitory activity than polyoxin D (IC50=70 microg/ml), a well-known chitin synthase inhibitor. These results indicate that the compound is a specific inhibitor of chitin synthase 2 from S. cerevisiae. In addition, CJ-01 showed antifungal activities against various human and phytopathogenic fungi. Therefore, the compound might be an interesting lead to develop effective antifungal agents.

Thin-film Nanofibrous Composite Membranes Containing Cellulose or Chitin Barrier Layers Fabricated by Ionic Liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

H Ma; B Hsiao; B Chu

The barrier layer of high-flux ultrafiltration (UF) thin-film nanofibrous composite (TFNC) membranes for purification of wastewater (e.g., bilge water) have been prepared by using cellulose, chitin, and a cellulose-chitin blend, regenerated from an ionic liquid. The structures and properties of regenerated cellulose, chitin, and a cellulose-chitin blend were analyzed with thermogravimetric analysis (TGA) and wide-angle X-ray diffraction (WAXD). The surface morphology, pore size and pore size distribution of TFNC membranes were determined by SEM images and molecular weight cut-off (MWCO) methods. An oil/water emulsion, a model of bilge water, was used as the feed solution, and the permeation flux andmore » rejection ratio of the membranes were investigated. TFNC membranes based on the cellulose-chitin blend exhibited 10 times higher permeation flux when compared with a commercial UF membrane (PAN10, Sepro) with a similar rejection ratio after filtration over a time period of up to 100 h, implying the practical feasibility of such membranes for UF applications.« less

Green Conversion of Agroindustrial Wastes into Chitin and Chitosan by Rhizopus arrhizus and Cunninghamella elegans Strains

PubMed Central

Berger, Lúcia Raquel Ramos; Stamford, Thayza Christina Montenegro; Stamford-Arnaud, Thatiana Montenegro; de Alcântara, Sergio Roberto Cabral; da Silva, Antonio Cardoso; da Silva, Adamares Marques; do Nascimento, Aline Elesbão; de Campos-Takaki, Galba Maria

2014-01-01

This article sets out a method for producing chitin and chitosan by Cunninghamella elegans and Rhizopus arrhizus strains using a green metabolic conversion of agroindustrial wastes (corn steep liquor and molasses). The physicochemical characteristics of the biopolymers and antimicrobial activity are described. Chitin and chitosan were extracted by alkali-acid treatment, and characterized by infrared spectroscopy, viscosity and X-ray diffraction. The effectiveness of chitosan from C. elegans and R. arrhizus in inhibiting the growth of Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica, Escherichia coli and Yersinia enterocolitica were evaluated by determining the minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC). The highest production of biomass (24.60 g/L), chitin (83.20 mg/g) and chitosan (49.31 mg/g) was obtained by R. arrhizus. Chitin and chitosan from both fungi showed a similar degree of deacetylation, respectively of 25% and 82%, crystallinity indices of 33.80% and 32.80% for chitin, and 20.30% and 17.80% for chitosan. Both chitin and chitosan presented similar viscosimetry of 3.79–3.40 cP and low molecular weight of 5.08 × 103 and 4.68 × 103 g/mol. They both showed identical MIC and MBC for all bacteria assayed. These results suggest that: agricultural wastes can be produced in an environmentally friendly way; chitin and chitosan can be produced economically; and that chitosan has antimicrobial potential against pathogenic bacteria. PMID:24853288

Characterization of chitin extracted from fish scales of marine fish species purchased from local markets in North Sulawesi, Indonesia

NASA Astrophysics Data System (ADS)

Rumengan, I. F. M.; Suptijah, P.; Wullur, S.; Talumepa, A.

2017-10-01

Chitin is a biodegradable biopolymer with a variety of commercial applications, including in the food food-supplement industries as a marine-derived nutraceutical. The purpose of this study was to characterize the molecular structure of chitin extracted from fish scales of important marine fish purchased from local markets in North Sulawesi. Chitin compound material was obtained from a specific fish scale, and then sequentially carrying out a boiling treatment to separate it from a complex with collagen. From the scales of two fish species, parrotfish (Chlorurus sordidus) and red snapper (Lutjanus argentimaculatus), the rendemen of chitin obtained were 45 % and 33%, respectively. Structural characteristics of the chitin were discussed by FTIR (Fourier Transform Infrared) analysis data. FTIR analysis was done using infrared spectroscopy, which is the resulting spectrum represents the molecular absorption and transmission, creating a molecular fingerprint of the sample. The molecular structure of chitin, C18H26N2O10, where the hydroxyl group on the second carbon replaced by acetyl amide, was shown by the infrared spectra. In the infrared spectra, chitin from parrot fish scales indicated the amide band at 1627.13 cm-1, and chitin from red snapper fish scales the amide band at 1648.09 cm-1 which are a typical one for marine chitin. The hydroxyl and amino bands at the ranged spectra up to 3500 cm-1. The yields of chitin isolated from fish scale were relatively huge. Some treatments are necessary to confirm the molecular conformation and deacetylation behavior. All products from the extraction of fish scales could be more accessible for structural modifications to develop biocompatible materials for pharmaceutical purposes.

Isolation and identification of chitin from heavy mineralized skeleton of Suberea clavata (Verongida: Demospongiae: Porifera) marine demosponge.

PubMed

Ehrlich, Hermann; Bazhenov, Vasilii V; Debitus, Cecile; de Voogd, Nicole; Galli, Roberta; Tsurkan, Mikhail V; Wysokowski, Marcin; Meissner, Heike; Bulut, Esra; Kaya, Murat; Jesionowski, Teofil

2017-11-01

Since the discovery of chitin in skeletal structures of sponges (Porifera) in 2007, studies on search of novel species which possess this structural aminopolysaccharide continue up today. The most potential source of chitin is suggested to be localized in the four families of sponges related to the order Verongida (Demospongiae) which nevertheless require further clarification. Here, we report for the first time the isolation and identification of α-chitin from the Suberea clavata demosponge (Aplysinidae: Verongida). Raman spectroscopy, Calcofluor White staining, chitinase test and ESI-MS techniques were used to identify chitin. We suggest that the presence of chitin within fibrous skeletons of diverse species of Verongida order, and, especially in all species of the Aplysinidae family, may be useful for the identification of novel, previously unidentified marine demosponges. Copyright © 2017 Elsevier B.V. All rights reserved.

Lipo-chitin oligosaccharides, plant symbiosis signalling molecules that modulate mammalian angiogenesis in vitro.

PubMed

Djordjevic, Michael A; Bezos, Anna; Susanti; Marmuse, Laurence; Driguez, Hugues; Samain, Eric; Vauzeilles, Boris; Beau, Jean-Marie; Kordbacheh, Farzaneh; Rolfe, Barry G; Schwörer, Ralf; Daines, Alison M; Gresshoff, Peter M; Parish, Christopher R

2014-01-01

Lipochitin oligosaccharides (LCOs) are signaling molecules required by ecologically and agronomically important bacteria and fungi to establish symbioses with diverse land plants. In plants, oligo-chitins and LCOs can differentially interact with different lysin motif (LysM) receptors and affect innate immunity responses or symbiosis-related pathways. In animals, oligo-chitins also induce innate immunity and other physiological responses but LCO recognition has not been demonstrated. Here LCO and LCO-like compounds are shown to be biologically active in mammals in a structure dependent way through the modulation of angiogenesis, a tightly-regulated process involving the induction and growth of new blood vessels from existing vessels. The testing of 24 LCO, LCO-like or oligo-chitin compounds resulted in structure-dependent effects on angiogenesis in vitro leading to promotion, or inhibition or nil effects. Like plants, the mammalian LCO biological activity depended upon the presence and type of terminal substitutions. Un-substituted oligo-chitins of similar chain lengths were unable to modulate angiogenesis indicating that mammalian cells, like plant cells, can distinguish between LCOs and un-substituted oligo-chitins. The cellular mode-of-action of the biologically active LCOs in mammals was determined. The stimulation or inhibition of endothelial cell adhesion to vitronectin or fibronectin correlated with their pro- or anti-angiogenic activity. Importantly, novel and more easily synthesised LCO-like disaccharide molecules were also biologically active and de-acetylated chitobiose was shown to be the primary structural basis of recognition. Given this, simpler chitin disaccharides derivatives based on the structure of biologically active LCOs were synthesised and purified and these showed biological activity in mammalian cells. Since important chronic disease states are linked to either insufficient or excessive angiogenesis, LCO and LCO-like molecules may have the

The Effect of Specific Surface Area of Chitin-Metal Silicate Coprocessed Excipient on the Chemical Decomposition of Cefotaxime Sodium.

PubMed

Al-Nimry, Suhair S; Alkhamis, Khouloud A; Alzarieni, Kawthar Z

2017-02-01

Chitin-metal silicates are multifunctional excipients used in tablets. Previously, a correlation between the surface acidity of chitin-calcium and chitin-magnesium silicate and the chemical decomposition of cefotaxime sodium was found but not with chitin-aluminum silicate. This lack of correlation could be due to the catalytic effect of silica alumina or the difference in surface area of the excipients. The objective of this study was to investigate the effect of the specific surface area of the excipient on the chemical decomposition of cefotaxime sodium in the solid state. Chitin was purified and coprocessed with different metal silicates to prepare the excipients. The specific surface area was determined using gas adsorption. The chemical decomposition was studied at constant temperature and relative humidity. Also, the degradation in solution was studied. A correlation was found between the degradation rate constant and the surface area of chitin-aluminum and chitin-calcium silicate but not with chitin-magnesium silicate. This was due to the small average pore diameter of this excipient. Also, the degradation in solution was slower than in solid state. In conclusion, the stability of cefotaxime sodium was dependent on the surface area of the excipient in contact with the drug. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

One-pot production of chitin with high purity from lobster shells using choline chloride-malonic acid deep eutectic solvent.

PubMed

Zhu, Ping; Gu, Zhongji; Hong, Shu; Lian, Hailan

2017-12-01

For the first time in this study, chitin was solely extracted from lobster shells through a fast, easy and eco-friendly method using deep eutectic solvents (DESs), consisting of mixtures of choline chloride-thiourea (CCT), choline chloride-urea (CCU), choline chloride-glycerol (CCG) and choline chloride-malonic acid (CCMA). The physiochemical properties of the isolated chitins were compared with those of the chemically prepared one and commercial one from shrimp shells. Results showed that CCT, CCU and CCG DESs had no important effect on the elimination of proteins and minerals, while chitin obtained by CCMA DES showed a high purity. The yield (20.63±3.30%) of chitin isolated by CCMA DES was higher than that (16.53±2.35%) of the chemically prepared chitin. The chitin obtained by CCMA DES could be divided into two parts with different crystallinity (67.2% and 80.6%), which also had different thermal stability. Chitin from lobster shells showed porous structure, which is expected to be used for adsorption materials and tissue engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hemocyanin with phenoloxidase activity in the chitin matrix of the crayfish gastrolith.

PubMed

Glazer, Lilah; Tom, Moshe; Weil, Simy; Roth, Ziv; Khalaila, Isam; Mittelman, Binyamin; Sagi, Amir

2013-05-15

Gastroliths are transient extracellular calcium deposits formed by the crayfish Cherax quadricarinatus von Martens on both sides of the stomach wall during pre-molt. Gastroliths are made of a rigid chitinous organic matrix, constructed as sclerotized chitin-protein microfibrils within which calcium carbonate is deposited. Although gastroliths share many characteristics with the exoskeleton, they are simpler in structure and relatively homogeneous in composition, making them an excellent cuticle-like model for the study of cuticular proteins. In searching for molt-related proteins involved in gastrolith formation, two integrated approaches were employed, namely the isolation and mass spectrometric analysis of proteins from the gastrolith matrix, and 454-sequencing of mRNAs from both the gastrolith-forming and sub-cuticular epithelia. SDS-PAGE separation of gastrolith proteins revealed a set of bands at apparent molecular masses of 75-85 kDa; mass spectrometry data matched peptide sequences from the deduced amino acid sequences of seven hemocyanin transcripts. This assignment was then examined by immunoblot analysis using anti-hemocyanin antibodies, also used to determine the spatial distribution of the proteins in situ. Apart from contributing to oxygen transport, crustacean hemocyanins were previously suggested to be involved in several aspects of the molt cycle, including hardening of the new post-molt exoskeleton via phenoloxidation. The phenoloxidase activity of gastrolith hemocyanins was demonstrated. It was also noted that hemocyanin transcript expression during pre-molt was specific to the hepatopancreas. Our results thus reflect a set of functionally versatile proteins, expressed in a remote metabolic tissue and dispersed via the hemolymph to perform different roles in various organs and structures.

Alkali- or acid-induced changes in structure, moisture absorption ability and deacetylating reaction of β-chitin extracted from jumbo squid (Dosidicus gigas) pens.

PubMed

Jung, Jooyeoun; Zhao, Yanyun

2014-01-01

Alkali- or acid-induced structural modifications in β-chitin from squid (Dosidicus gigas, d'Orbigny, 1835) pens and their moisture absorption ability (MAA) and deacetylating reaction were investigated and compared with α-chitin from shrimp shells. β-Chitin was converted into the α-form after 3h in 40% NaOH or 1-3 h in 40% HCl solution, and α-chitin obtained from NaOH treatment had higher MAA than had native α-chitin, due to polymorphic destructions. In contrast, induced α-chitin from acid treatment of β-chitin had few polymorphic modifications, showing no significant change (P>0.05) in MAA. β-Chitin was more susceptible to alkali deacetylation than was α-chitin, and required a lower concentration of NaOH and shorter reaction time. These results demonstrate that alkali- or acid-treated β-chitin retained high susceptibility toward solvents, which in turn resulted in good biological activity of β-chitosan for use as a natural antioxidant and antimicrobial substance or application as edible coatings and films for various food applications. Published by Elsevier Ltd.

Chitin amendment increases soil suppressiveness toward plant pathogens and modulates the actinobacterial and oxalobacteraceal communities in an experimental agricultural field.

PubMed

Cretoiu, Mariana Silvia; Korthals, Gerard W; Visser, Johnny H M; van Elsas, Jan Dirk

2013-09-01

A long-term experiment on the effect of chitin addition to soil on the suppression of soilborne pathogens was set up and monitored for 8 years in an experimental field, Vredepeel, The Netherlands. Chitinous matter obtained from shrimps was added to soil top layers on two different occasions, and the suppressiveness of soil toward Verticillium dahliae, as well as plant-pathogenic nematodes, was assessed, in addition to analyses of the abundances and community structures of members of the soil microbiota. The data revealed that chitin amendment had raised the suppressiveness of soil, in particular toward Verticillium dahliae, 9 months after the (second) treatment, extending to 2 years following treatment. Moreover, major effects of the added chitin on the soil microbial communities were detected. First, shifts in both the abundances and structures of the chitin-treated soil microbial communities, both of total soil bacteria and fungi, were found. In addition, the abundances and structures of soil actinobacteria and the Oxalobacteraceae were affected by chitin. At the functional gene level, the abundance of specific (family-18 glycoside hydrolase) chitinase genes carried by the soil bacteria also revealed upshifts as a result of the added chitin. The effects of chitin noted for the Oxalobacteraceae were specifically related to significant upshifts in the abundances of the species Duganella violaceinigra and Massilia plicata. These effects of chitin persisted over the time of the experiment.

Chitin Amendment Increases Soil Suppressiveness toward Plant Pathogens and Modulates the Actinobacterial and Oxalobacteraceal Communities in an Experimental Agricultural Field

PubMed Central

Cretoiu, Mariana Silvia; Korthals, Gerard W.; Visser, Johnny H. M.

2013-01-01

A long-term experiment on the effect of chitin addition to soil on the suppression of soilborne pathogens was set up and monitored for 8 years in an experimental field, Vredepeel, The Netherlands. Chitinous matter obtained from shrimps was added to soil top layers on two different occasions, and the suppressiveness of soil toward Verticillium dahliae, as well as plant-pathogenic nematodes, was assessed, in addition to analyses of the abundances and community structures of members of the soil microbiota. The data revealed that chitin amendment had raised the suppressiveness of soil, in particular toward Verticillium dahliae, 9 months after the (second) treatment, extending to 2 years following treatment. Moreover, major effects of the added chitin on the soil microbial communities were detected. First, shifts in both the abundances and structures of the chitin-treated soil microbial communities, both of total soil bacteria and fungi, were found. In addition, the abundances and structures of soil actinobacteria and the Oxalobacteraceae were affected by chitin. At the functional gene level, the abundance of specific (family-18 glycoside hydrolase) chitinase genes carried by the soil bacteria also revealed upshifts as a result of the added chitin. The effects of chitin noted for the Oxalobacteraceae were specifically related to significant upshifts in the abundances of the species Duganella violaceinigra and Massilia plicata. These effects of chitin persisted over the time of the experiment. PMID:23811512

Chitin's Functionality as a Novel Disintegrant: Benchmarking Against Commonly Used Disintegrants in Different Physicochemical Environments.

PubMed

Chaheen, Mohammad; Soulairol, Ian; Bataille, Bernard; Yassine, Ahmad; Belamie, Emmanuel; Sharkawi, Tahmer

2017-07-01

Disintegrants are used as excipients to ensure rapid disintegration of pharmaceutical tablets and further ensure proper dissolution of the active pharmaceutical ingredient. This study investigates disintegration mechanisms of chitin and common disintegrants. Swelling assessment (swelling force and swelling ratio) in different media, and compaction behavior (pure or mixed with other excipients) tabletability, deformation (Heckel modeling), and compact disintegration times were investigated on the tested disintegrants (alginic acid calcium salt, crospovidone, sodium starch glycolate, croscarmellose sodium, and chitin). Results show that the physicochemical properties of the disintegration medium such as pH and ionic strength, as well as other formulation ingredients, affect the disintegrant functionalities. Heckel analysis using the mean yield pressure "Py" shows that alginic acid calcium salt is the most brittle among the studied disintegrants, while crospovidone has the most plastic deformation mechanism, followed by chitin. Chitin showed good tabletability and disintegration properties that were not influenced by the physicochemical formulation environment. Chitin is largely available and easily modifiable and thus a promising material that could be used as a multifunctional excipient in tablet formulation. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Chitin and Chitosan Preparation from Marine Sources. Structure, Properties and Applications

PubMed Central

Younes, Islem; Rinaudo, Marguerite

2015-01-01

This review describes the most common methods for recovery of chitin from marine organisms. In depth, both enzymatic and chemical treatments for the step of deproteinization are compared, as well as different conditions for demineralization. The conditions of chitosan preparation are also discussed, since they significantly impact the synthesis of chitosan with varying degree of acetylation (DA) and molecular weight (MW). In addition, the main characterization techniques applied for chitin and chitosan are recalled, pointing out the role of their solubility in relation with the chemical structure (mainly the acetyl group distribution along the backbone). Biological activities are also presented, such as: antibacterial, antifungal, antitumor and antioxidant. Interestingly, the relationship between chemical structure and biological activity is demonstrated for chitosan molecules with different DA and MW and homogeneous distribution of acetyl groups for the first time. In the end, several selected pharmaceutical and biomedical applications are presented, in which chitin and chitosan are recognized as new biomaterials taking advantage of their biocompatibility and biodegradability. PMID:25738328

Powdered Chitin Agar as a Selective Medium for Enumeration of Actinomycetes in Water and Soil1

PubMed Central

Hsu, S. C.; Lockwood, J. L.

1975-01-01

Agar media made with 0.4% colloidal chitin plus mineral salts and adjusted to pH 8.0 was superior to four other commonly used media for the isolation and enumeration of actinomycetes from water samples. More actinomycetes developed on chitin agar, and the development of bacteria and fungi was suppressed. Frozen and vacuum-dried chitin from aqueous colloidal suspensions was finely divided and gave results comparable to those obtained with media prepared from colloidal suspensions. Images PMID:234719

Current Status and New Perspectives on Chitin and Chitosan as Functional Biopolymers.

PubMed

Philibert, Tuyishime; Lee, Byong H; Fabien, Nsanzabera

2017-04-01

The natural biopolymer chitin and its deacetylated product chitosan are found abundantly in nature as structural building blocks and are used in all sectors of human activities like materials science, nutrition, health care, and energy. Far from being fully recognized, these polymers are able to open opportunities for completely novel applications due to their exceptional properties which an economic value is intrinsically entrapped. On a commercial scale, chitosan is mainly obtained from crustacean shells rather than from the fungal and insect sources. Significant efforts have been devoted to commercialize chitosan extracted from fungal and insect sources to completely replace crustacean-derived chitosan. However, the traditional chitin extraction processes are laden with many disadvantages. The present review discusses the potential bioextraction of chitosan from fungal, insect, and crustacean as well as its superior physico-chemical properties. The different aspects of fungal, insects, and crustacean chitosan extraction methods and various parameters having an effect on the yield of chitin and chitosan are discussed in detail. In addition, this review also deals with essential attributes of chitosan for high value-added applications in different fields and highlighted new perspectives on the production of chitin and deacetylated chitosan from different sources with the concomitant reduction of the environmental impact.

[Applications of near infrared reflectance spectroscopy in detecting chitin, ergosterol and mycotoxins].

PubMed

Yi, Yong-Yan; Li, De-Rong; Zhang, Yun-Wei; Yang, Fu-Yu

2009-07-01

The invasion extent and harmfulness of fungi can be determined by chitin, ergosterol and mycotoxins. It is important to monitor chitin, ergosterol and mycotoxins changes to prevent contamination of forage and feed products, and effectively control the sustainable development of the mildew. Predication of these chemical materials was often completed by laboratory analysis, which was time-consuming and cumbersome and could not reflect the results in time in the past. Near infrared reflectance spectroscopy (NIRS) is a rapid, convenient, highly efficient, nondestructive and low-cost analytical technique, which has been widely used in various fields such as food field and feed field for quantitative and qualitative analysis. It has a great potentiality of application in quality analysis. In this paper, the principle and the characteristic of NIRS and its applications in food, forage, feed and other agriculture products quality analysis were introduced. Its applications in fungal biomass (chitin, ergosterol) and mycotoxins were mainly reviewed. NIRS was used to quantify chitin, ergosterol and mycotoxins. Calibration equations and validation equations for these materials were developed. It is also expected that NIRS will play a more and more important role in the field of fungi with the establishment of calibration equation and improvement of model database.

Cell wall domain and moisture content influence southern pine electrical conductivity

Treesearch

Samuel L. Zelinka; Leandro Passarini; José L. Colon Quintana; Samuel V. Glass; Joseph E. Jakes; Alex C. Wiedenhoeft

2016-01-01

Recent work has highlighted the importance of movement of chemicals and ions through the wood cell wall. This movement depends strongly on moisture content and is necessary for structural damage mechanisms such as fastener corrosion and wood decay. Here, we present the first measurements of electrical resistance of southern pine at the subcellular level as a function...

The cell wall: a carbohydrate armour for the fungal cell.

PubMed

Latgé, Jean-Paul

2007-10-01

The cell wall is composed of a polysaccharide-based three-dimensional network. Considered for a long time as an inert exoskeleton, the cell wall is now seen as a dynamic structure that is continuously changing as a result of the modification of culture conditions and environmental stresses. Although the cell wall composition varies among fungal species, chemogenomic comparative analysis have led to a better understanding of the genes and mechanisms involved in the construction of the common central core composed of branched beta1,3 glucan-chitin. Because of its essential biological role, unique biochemistry and structural organization and the absence in mammalian cells of most of its constitutive components, the cell wall is an attractive target for the development of new antifungal agents. Genomic as well as drug studies have shown that the death of the fungus can result from inhibition of cell wall polysaccharide synthases. To date, only beta1,3 glucan synthase inhibitors have been launched clinically and many more targets remain to be explored.

One-pot synthesis of MnO2-chitin hybrids for effective removal of methylene blue.

PubMed

Dassanayake, Rohan S; Rajakaruna, Erandathi; Moussa, Hanna; Abidi, Noureddine

2016-12-01

Manganese dioxide (MnO 2 )-chitin-hybrid material was prepared by a facile "one-pot" synthesis method. MnO 2 -chitin hybrid was used for the effective removal of methylene blue (MB) from liquid solution as model for wastewater treatment. The hybrid obtained was characterized by field emission scanning electron microscopy and energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. The effect of pH and temperature were studied. MnO 2 -chitin hybrid showed high performance for oxidative decolorization and removal of MB. Typically, 25mL of MB (20mg/L) can be completely decolorized in 2.5min with 8.5mg of the MnO 2 -chitin hybrid. The hybrid material exhibited excellent recyclability and durability with the degradation value of 99% for MB after ten consecutive cycles. Copyright © 2016 Elsevier B.V. All rights reserved.

Chitin synthase in the filarial parasite, Brugia malayi.

PubMed

Harris, M T; Lai, K; Arnold, K; Martinez, H F; Specht, C A; Fuhrman, J A

2000-12-01

Fragments of putative chitin synthase (chs) genes from two filarial species (Brugia malayi and Dirofilaria immitis) were amplified by PCR using degenerate primers. The full genomic and cDNA sequences were obtained for the B. malayi chs gene (Bm-chs-1); the predicted amino acid sequence is highly similar, over a large region, to two CHS sequences of the nematode Caenorhabditis elegans and also to two insect CHS sequences. Bm-chs-1 is abundantly transcribed in B. malayi adult females, independent of their fertilization status, but is also expressed in males and microfilariae. Oocytes and early embryos contain large amounts of Bm-chs-1 transcript by in situ hybridization, but later stage embryos within the maternal uterus show little or no Bm-chs-1 transcript. No specific hybridization could be demonstrated in maternal somatic tissues. Polyclonal antibodies were raised against a peptide expressed from a recombinant cDNA fragment of Bm-chs-1; immunostaining detected CHS protein in oocytes and early to midstage embryos. These studies characterize a gene that is likely to be essential to oogenesis and embryonic development in a parasitic nematode. Because chitin synthesis and eggshell formation begin after fertilization, the presence of CHS protein in early oocytes suggests that the enzyme must be activated as a result of fertilization. These studies also demonstrate that chitin synthesis may not be restricted to eggshell formation in nematodes, as the Bm-chs-1 gene is transcribed in life cycle stages other than adult females.

Papain incorporated chitin dressings for wound debridement sterilized by gamma radiation

NASA Astrophysics Data System (ADS)

Singh, Durgeshwer; Singh, Rita

2012-11-01

Wound debridement is essential for the removal of necrotic or nonviable tissue from the wound surface to create an environment conducive to healing. Nonsurgical enzymatic debridement is an attractive method due to its effectiveness and ease of use. Papain is a proteolytic enzyme derived from the fruit of Carica papaya and is capable of breaking down a variety of necrotic tissue substrates. The present study was focused on the use of gamma radiation for sterilization of papain dressing with wound debriding activity. Membranes with papain were prepared using 0.5% chitin in lithium chloride/dimethylacetamide solvent and sterilized by gamma radiation. Fluid absorption capacity of chitin-papain membranes without glycerol was 14.30±6.57% in 6 h. Incorporation of glycerol resulted in significant (p<0.001) increase in the absorption capacity. Moisture vapour transmission rate of the membranes was 4285.77±455.61 g/m2/24 h at 24 h. Gamma irradiation at 25 kGy was found suitable for sterilization of the dressings. Infrared (IR) spectral scanning has shown that papain was stable on gamma irradiation at 25-35 kGy. The irradiated chitin-papain membranes were impermeable to different bacterial strains and also exhibited strong bactericidal action against both Gram-positive and Gram-negative bacteria. The fluid handling characteristics and the antimicrobial properties of chitin-papain membranes sterilized by gamma radiation were found suitable for use as wound dressing with debriding activity.

Optimization of extraction of chitin from procambarus clarkia shell by Box-Behnken design

NASA Astrophysics Data System (ADS)

Dong, Fang; Qiu, Hailong; Jia, Shaoqian; Dai, Cuiping; Kong, Qingxin; Xu, Changliang

2018-06-01

This paper investigated the optimizing extraction processing of chitin from procambarus clarkia shell by Box-Behnken design. Firstly, four independent variables were explored in single factor experiments, namely, concentration of hydrochloric acid, soaking time, concentration of sodium hydroxide and reaction time. Then, based on the results of the above experiments, four factors and three levels experiments were planned by Box-Behnken design. According to the experimental results, we harvested a second-order polynomial equation using multiple regression analysis. In addition, the optimum extraction process of chitin of the model was obtained: concentration of HCl solution 1.54mol/L, soaking time 19.87h, concentration of NaOH solution 2.9mol/L and reaction time 3.54h. For proving the accuracy of the model, we finished the verification experiment under the following conditions: concentration of hydrochloric acid 1.5mol/L, soaking time 20h, concentration of sodium hydroxide 3mol/L and reaction time 3.5h. The actual yield of chitin reached 18.76%, which was very close to the predicted yield (18.66%) of the model. The result indicated that the optimum extraction processing of chitin was feasible and practical.

Effect of acidity on the physicochemical properties of α- and β-chitin nanofibers.

PubMed

Suenaga, Shin; Totani, Kazuhide; Nomura, Yoshihiro; Yamashita, Kazuhiko; Shimada, Iori; Fukunaga, Hiroshi; Takahashi, Nobuhide; Osada, Mitsumasa

2017-09-01

We have investigated whether acidity can be used to control the physicochemical properties of chitin nanofibers (ChNFs). In this study, we define acidity as the molar ratio of dissociated protons from the acid to the amino groups in the raw chitin powder. The effect of acidity on the physicochemical properties of α- and β-ChNFs was compared. The transmittance and viscosity of the β-ChNFs drastically and continuously increased with increasing acidity, while those of the α-ChNFs were not affected by acidity. These differences are because of the higher ability for cationization based on the more flexible crystal structure of β-chitin than α-chitin. In addition, the effect of the acid species on the transmittance of β-ChNFs was investigated. The transmittance of β-ChNFs can be expressed by the acidity regardless of the acid species, such as hydrochloric acid, phosphoric acid, and acetic acid. These results indicate that the acidity defined in this work is an effective parameter to define and control the physicochemical properties of ChNFs. Copyright © 2017 Elsevier B.V. All rights reserved.

Isolation of proteolytic bacteria from mealworm (Tenebrio molitor) exoskeletons to produce chitinous material.

PubMed

da Silva, Fernanda Kerche Paes; Brück, Dieter W; Brück, Wolfram M

2017-09-15

The use of insects as a source of protein is becoming an important factor for feeding an increasing population. After protein extraction for food use, the insect exoskeleton may offer the possibility for the production of added value products. Here, the aim was to isolate bacteria from the surface of farmed mealworms (Tenebrio molitor Linnaeus, 1758) for the production of chitinous material from insect exoskeletons using microbial fermentation. Isolates were screened for proteases and acid production that may aid deproteination and demineralisation of insects through fermentation to produce chitin. Selected isolates were used single-step (isolated bacteria only) or two-step fermentations with Lactobacillus plantarum (DSM 20174). Two-step fermentations with isolates from mealworm exoskeletons resulted in a demineralisation of 97.9 and 98.5% from deproteinated mealworm fractions. Attenuated total reflectance-Fourier- transform infrared spectroscopy analysis showed that crude chitin was produced. However, further optimisation is needed before the process can be upscaled. This is, to our knowledge, the first report using microbial fermentation for the extraction of chitin from insects. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Chitin recognition via chitotriosidase promotes pathologic type-2 helper T cell responses to cryptococcal infection.

PubMed

Wiesner, Darin L; Specht, Charles A; Lee, Chrono K; Smith, Kyle D; Mukaremera, Liliane; Lee, S Thera; Lee, Chun G; Elias, Jack A; Nielsen, Judith N; Boulware, David R; Bohjanen, Paul R; Jenkins, Marc K; Levitz, Stuart M; Nielsen, Kirsten

2015-03-01

Pulmonary mycoses are often associated with type-2 helper T (Th2) cell responses. However, mechanisms of Th2 cell accumulation are multifactorial and incompletely known. To investigate Th2 cell responses to pulmonary fungal infection, we developed a peptide-MHCII tetramer to track antigen-specific CD4+ T cells produced in response to infection with the fungal pathogen Cryptococcus neoformans. We noted massive accruement of pathologic cryptococcal antigen-specific Th2 cells in the lungs following infection that was coordinated by lung-resident CD11b+ IRF4-dependent conventional dendritic cells. Other researchers have demonstrated that this dendritic cell subset is also capable of priming protective Th17 cell responses to another pulmonary fungal infection, Aspergillus fumigatus. Thus, higher order detection of specific features of fungal infection by these dendritic cells must direct Th2 cell lineage commitment. Since chitin-containing parasites commonly elicit Th2 responses, we hypothesized that recognition of fungal chitin is an important determinant of Th2 cell-mediated mycosis. Using C. neoformans mutants or purified chitin, we found that chitin abundance impacted Th2 cell accumulation and disease. Importantly, we determined Th2 cell induction depended on cleavage of chitin via the mammalian chitinase, chitotriosidase, an enzyme that was also prevalent in humans experiencing overt cryptococcosis. The data presented herein offers a new perspective on fungal disease susceptibility, whereby chitin recognition via chitotriosidase leads to the initiation of harmful Th2 cell differentiation by CD11b+ conventional dendritic cells in response to pulmonary fungal infection.

Chitin Recognition via Chitotriosidase Promotes Pathologic Type-2 Helper T Cell Responses to Cryptococcal Infection

PubMed Central

Wiesner, Darin L.; Specht, Charles A.; Lee, Chrono K.; Smith, Kyle D.; Mukaremera, Liliane; Lee, S. Thera; Lee, Chun G.; Elias, Jack A.; Nielsen, Judith N.; Boulware, David R.; Bohjanen, Paul R.; Jenkins, Marc K.; Levitz, Stuart M.; Nielsen, Kirsten

2015-01-01

Pulmonary mycoses are often associated with type-2 helper T (Th2) cell responses. However, mechanisms of Th2 cell accumulation are multifactorial and incompletely known. To investigate Th2 cell responses to pulmonary fungal infection, we developed a peptide-MHCII tetramer to track antigen-specific CD4+ T cells produced in response to infection with the fungal pathogen Cryptococcus neoformans. We noted massive accruement of pathologic cryptococcal antigen-specific Th2 cells in the lungs following infection that was coordinated by lung-resident CD11b+ IRF4-dependent conventional dendritic cells. Other researchers have demonstrated that this dendritic cell subset is also capable of priming protective Th17 cell responses to another pulmonary fungal infection, Aspergillus fumigatus. Thus, higher order detection of specific features of fungal infection by these dendritic cells must direct Th2 cell lineage commitment. Since chitin-containing parasites commonly elicit Th2 responses, we hypothesized that recognition of fungal chitin is an important determinant of Th2 cell-mediated mycosis. Using C. neoformans mutants or purified chitin, we found that chitin abundance impacted Th2 cell accumulation and disease. Importantly, we determined Th2 cell induction depended on cleavage of chitin via the mammalian chitinase, chitotriosidase, an enzyme that was also prevalent in humans experiencing overt cryptococcosis. The data presented herein offers a new perspective on fungal disease susceptibility, whereby chitin recognition via chitotriosidase leads to the initiation of harmful Th2 cell differentiation by CD11b+ conventional dendritic cells in response to pulmonary fungal infection. PMID:25764512

Sensitivity of Aspergillus nidulans to the Cellulose Synthase Inhibitor Dichlobenil: Insights from Wall-Related Genes’ Expression and Ultrastructural Hyphal Morphologies

PubMed Central

Obersriebnig, Michael; Salerno, Marco; Pum, Dietmar; Strauss, Joseph

2013-01-01

The fungal cell wall constitutes an important target for the development of antifungal drugs, because of its central role in morphogenesis, development and determination of fungal-specific molecular features. Fungal walls are characterized by a network of interconnected glycoproteins and polysaccharides, namely α-, β-glucans and chitin. Cell walls promptly and dynamically respond to environmental stimuli by a signaling mechanism, which triggers, among other responses, modulations in wall biosynthetic genes’ expression. Despite the absence of cellulose in the wall of the model filamentous fungus Aspergillus nidulans, we found in this study that fungal growth, spore germination and morphology are affected by the addition of the cellulose synthase inhibitor dichlobenil. Expression analysis of selected genes putatively involved in cell wall biosynthesis, carried out at different time points of drug exposure (i.e. 0, 1, 3, 6 and 24 h), revealed increased expression for the putative mixed linkage β-1,3;1,4 glucan synthase celA together with the β-1,3-glucan synthase fksA and the Rho-related GTPase rhoA. We also compared these data with the response to Congo Red, a known plant/fungal drug affecting both chitin and cellulose biosynthesis. The two drugs exerted different effects at the cell wall level, as shown by gene expression analysis and the ultrastructural features observed through atomic force microscopy and scanning electron microscopy. Although the concentration of dichlobenil required to affect growth of A. nidulans is approximately 10-fold higher than that required to inhibit plant cellulose biosynthesis, our work for the first time demonstrates that a cellulose biosynthesis inhibitor affects fungal growth, changes fungal morphology and expression of genes connected to fungal cell wall biosynthesis. PMID:24312197

Constitutive expression of cell wall invertase genes increases grain yield and starch content in maize.

PubMed

Li, Bei; Liu, Hua; Zhang, Yue; Kang, Tao; Zhang, Li; Tong, Jianhua; Xiao, Langtao; Zhang, Hongxia

2013-12-01

Grain size, number and starch content are important determinants of grain yield and quality. One of the most important biological processes that determine these components is the carbon partitioning during the early grain filling, which requires the function of cell wall invertase. Here, we showed the constitutive expression of cell wall invertase-encoding gene from Arabidopsis, rice (Oryza sativa) or maize (Zea mays), driven by the cauliflower mosaic virus (CaMV) 35S promoter, all increased cell wall invertase activities in different tissues and organs, including leaves and developing seeds, and substantially improved grain yield up to 145.3% in transgenic maize plants as compared to the wild-type plants, an effect that was reproduced in our 2-year field trials at different locations. The dramatically increased grain yield is due to the enlarged ears with both enhanced grain size and grain number. Constitutive expression of the invertase-encoding gene also increased total starch content up to 20% in the transgenic kernels. Our results suggest that cell wall invertase gene can be genetically engineered to improve both grain yield and grain quality in crop plants. © 2013 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Fabrication of chitin-chitosan/nano TiO2-composite scaffolds for tissue engineering applications.

PubMed

Jayakumar, R; Ramachandran, Roshni; Divyarani, V V; Chennazhi, K P; Tamura, H; Nair, S V

2011-03-01

In this study, we prepared chitin-chitosan/nano TiO(2) composite scaffolds using lyophilization technique for bone tissue engineering. The prepared composite scaffold was characterized using SEM, XRD, FTIR and TGA. In addition, swelling, degradation and biomineralization capability of the composite scaffolds were evaluated. The developed composite scaffold showed controlled swelling and degradation when compared to the control scaffold. Cytocompatibility of the scaffold was assessed by MTT assay and cell attachment studies using osteoblast-like cells (MG-63), fibroblast cells (L929) and human mesenchymal stem cells (hMSCs). Results indicated no sign of toxicity and cells were found attached to the pore walls within the scaffolds. These results suggested that the developed composite scaffold possess the prerequisites for tissue engineering scaffolds and it can be used for tissue engineering applications. Copyright © 2010 Elsevier B.V. All rights reserved.

Analysis of expression and chitin-binding activity of the wing disc cuticle protein BmWCP4 in the silkworm, Bombyx mori.

PubMed

Deng, Hui-Min; Li, Yong; Zhang, Jia-Ling; Liu, Lin; Feng, Qi-Li

2016-12-01

The insect exoskeleton is mainly composed of chitin filaments linked by cuticle proteins. When insects molt, the cuticle of the exoskeleton is renewed by degrading the old chitin and cuticle proteins and synthesizing new ones. In this study, chitin-binding activity of the wing disc cuticle protein BmWCP4 in Bombyx mori was studied. Sequence analysis showed that the protein had a conservative hydrophilic "R&R" chitin-binding domain (CBD). Western blotting showed that BmWCP4 was predominately expressed in the wing disc-containing epidermis during the late wandering and early pupal stages. The immunohistochemistry result showed that the BmWCP4 was mainly present in the wing disc tissues containing wing bud and trachea blast during day 2 of wandering stage. Recombinant full-length BmWCP4 protein, "R&R" CBD peptide (CBD), non-CBD peptide (BmWCP4-CBD - ), four single site-directed mutated peptides (M 1 , M 2 , M 3 and M 4 ) and four-sites-mutated peptide (M F ) were generated and purified, respectively, for in vitro chitin-binding assay. The results indicated that both the full-length protein and the "R&R" CBD peptide could bind with chitin, whereas the BmWCP4-CBD - could not bind with chitin. The single residue mutants M 1 , M 2 , M 3 and M 4 reduced but did not completely abolish the chitin-binding activity, while four-sites-mutated protein M F completely lost the chitin-binding activity. These data indicate that BmWCP4 protein plays a critical role by binding to the chitin filaments in the wing during larva-to-pupa transformation. The conserved aromatic amino acids are critical in the interaction between chitin and the cuticle protein. © 2015 Institute of Zoology, Chinese Academy of Sciences.

Targeting of Chitin Synthase 3 to Polarized Growth Sites in Yeast Requires Chs5p and Myo2p

PubMed Central

Santos, Beatriz; Snyder, Michael

1997-01-01

Chitin is an essential structural component of the yeast cell wall whose deposition is regulated throughout the yeast life cycle. The temporal and spatial regulation of chitin synthesis was investigated during vegetative growth and mating of Saccharomyces cerevisiae by localization of the putative catalytic subunit of chitin synthase III, Chs3p, and its regulator, Chs5p. Immunolocalization of epitope-tagged Chs3p revealed a novel localization pattern that is cell cycledependent. Chs3p is polarized as a diffuse ring at the incipient bud site and at the neck between the mother and bud in small-budded cells; it is not found at the neck in large-budded cells containing a single nucleus. In large-budded cells undergoing cytokinesis, it reappears as a ring at the neck. In cells responding to mating pheromone, Chs3p is found throughout the projection. The appearance of Chs3p at cortical sites correlates with times that chitin synthesis is expected to occur. In addition to its localization at the incipient bud site and neck, Chs3p is also found in cytoplasmic patches in cells at different stages of the cell cycle. Epitope-tagged Chs5p also localizes to cytoplasmic patches; these patches contain Kex2p, a late Golgi-associated enzyme. Unlike Chs3p, Chs5p does not accumulate at the incipient bud site or neck. Nearly all Chs3p patches contain Chs5p, whereas some Chs5p patches lack detectable Chs3p. In the absence of Chs5p, Chs3p localizes in cytoplasmic patches, but it is no longer found at the neck or the incipient bud site, indicating that Chs5p is required for the polarization of Chs3p. Furthermore, Chs5p localization is not affected either by temperature shift or by the myo2-66 mutation, however, Chs3p polarization is affected by temperature shift and myo2-66. We suggest a model in which Chs3p polarization to cortical sites in yeast is dependent on both Chs5p and the actin cytoskeleton/Myo2p. PMID:9008706

Proteomic investigation of the secretome of Cellvibrio japonicus during growth on chitin.

PubMed

Tuveng, Tina Rise; Arntzen, Magnus Øverlie; Bengtsson, Oskar; Gardner, Jeffrey G; Vaaje-Kolstad, Gustav; Eijsink, Vincent G H

2016-07-01

Studies of the secretomes of microbes grown on insoluble substrates are important for the discovery of novel proteins involved in biomass conversion. However, data in literature and this study indicate that secretome samples tend to be contaminated with cytoplasmic proteins. We have examined the secretome of the Gram-negative soil bacterium Cellvibrio japonicus using a simple plate-based culturing technique that yields samples with high fractions (60-75%) of proteins that are predicted to be secreted. By combining this approach with label-free quantification using the MaxLFQ algorithm, we have mapped and quantified proteins secreted by C. japonicus during growth on α- and β-chitin. Hierarchical clustering of the detected protein quantities revealed groups of up-regulated proteins that include all five putative C. japonicus chitinases as well as a chitin-specific lytic polysaccharide monooxygenase (CjLPMO10A). A small set of secreted proteins were co-regulated with known chitin-specific enzymes, including several with unknown catalytic functions. These proteins provide interesting targets for further studies aimed at unraveling the enzymatic machineries used by C. japonicus for recalcitrant polysaccharide degradation. Studies of chitin degradation indicated that C. japonicus indeed produces an efficient chitinolytic enzyme cocktail. All MS data have been deposited in the ProteomeXchange with the dataset identifier PXD002843 (http://proteomecentral.proteomexchange.org/dataset/PXD002843). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sequence of a cDNA and expression of the gene encoding a putative epidermal chitin synthase of Manduca sexta.

PubMed

Zhu, Yu-Cheng; Specht, Charles A; Dittmer, Neal T; Muthukrishnan, Subbaratnam; Kanost, Michael R; Kramer, Karl J

2002-11-01

Glycosyltransferases are enzymes that synthesize oligosaccharides, polysaccharides and glycoconjugates. One type of glycosyltransferase is chitin synthase, a very important enzyme in biology, which is utilized by insects, fungi, and other invertebrates to produce chitin, a polysaccharide of beta-1,4-linked N-acetylglucosamine. Chitin is an important component of the insect's exoskeletal cuticle and gut lining. To identify and characterize a chitin synthase gene of the tobacco hornworm, Manduca sexta, degenerate primers were designed from two highly conserved regions in fungal and nematode chitin synthase protein sequences and then used to amplify a similar region from Manduca cDNA. A full-length cDNA of 5152 nucleotides was assembled for the putative Manduca chitin synthase gene, MsCHS1, and sequencing of genomic DNA verified the contiguity of the sequence. The MsCHS1 cDNA has an ORF of 4692 nucleotides that encodes a transmembrane protein of 1564 amino acid residues with a mass of approximately 179 kDa (GenBank no. AY062175). It is most similar, over its entire length of protein sequence, to putative chitin synthases from other insects and nematodes, with 68% identity to enzymes from both the blow fly, Lucilia cuprina, and the fruit fly, Drosophila melanogaster. The similarity with fungal chitin synthases is restricted to the putative catalytic domain, and the MsCHS1 protein has, at equivalent positions, several amino acids that are essential for activity as revealed by mutagenesis of the fungal enzymes. A 5.3-kb transcript of MsCHS1 was identified by northern blot hybridization of RNA from larval epidermis, suggesting that the enzyme functions to make chitin deposited in the cuticle. Further examination by RT-PCR showed that MsCHS1 expression is regulated in the epidermis, with the amount of transcript increasing during phases of cuticle deposition.

The role of the cell wall in fungal pathogenesis

PubMed Central

Arana, David M.; Prieto, Daniel; Román, Elvira; Nombela, César; Alonso‐Monge, Rebeca; Pla, Jesús

2009-01-01

Summary Fungal infections are a serious health problem. In recent years, basic research is focusing on the identification of fungal virulence factors as promising targets for the development of novel antifungals. The wall, as the most external cellular component, plays a crucial role in the interaction with host cells mediating processes such as adhesion or phagocytosis that are essential during infection. Specific components of the cell wall (called PAMPs) interact with specific receptors in the immune cell (called PRRs), triggering responses whose molecular mechanisms are being elucidated. We review here the main structural carbohydrate components of the fungal wall (glucan, mannan and chitin), how their biogenesis takes place in fungi and the specific receptors that they interact with. Different model fungal pathogens are chosen to illustrate the functional consequences of this interaction. Finally, the identification of the key components will have important consequences in the future and will allow better approaches to treat fungal infections. PMID:21261926

Evaluation of wound healing potential of β-chitin hydrogel/nano zinc oxide composite bandage.

PubMed

P T, Sudheesh Kumar; Lakshmanan, Vinoth-Kumar; Raj, Mincy; Biswas, Raja; Hiroshi, Tamura; Nair, Shantikumar V; Jayakumar, Rangasamy

2013-02-01

β-chitin hydrogel/nZnO composite bandage was fabricated and evaluated in detail as an alternative to existing bandages. β-chitin hydrogel was synthesized by dissolving β-chitin powder in Methanol/CaCl(2) solvent, followed by the addition of distilled water. ZnO nanoparticles were added to the β-chitin hydrogel and stirred for homogenized distribution. The resultant slurry was frozen at 0°C for 12 h. The frozen samples were lyophilized for 24 h to obtain porous composite bandages. The bandages showed controlled swelling and degradation. The composite bandages showed blood clotting ability as well as platelet activation, which was higher when compared to the control. The antibacterial activity of the bandages were proven against Staphylococcus aureus (S. aureus) and Escherichia coli (E.coli). Cytocompatibility of the composite bandages were assessed using human dermal fibroblast cells (HDF) and these cells on the composite bandages were viable similar to the Kaltostat control bandages and bare β-chitin hydrogel based bandages. The viability was reduced to 50-60% in bandages with higher concentration of zinc oxide nanoparticles (nZnO) and showed 80-90% viability with lower concentration of nZnO. In vivo evaluation in Sprague Dawley rats (S.D. rats) showed faster healing and higher collagen deposition ability of composite bandages when compared to the control. The prepared bandages can be used on various types of infected wounds with large volume of exudates.

Removal of 2,4-D from aqueous solutions by adsorption processes using two biopolymers: chitin and chitosan and their optical properties

NASA Astrophysics Data System (ADS)

El Harmoudi, H.; El Gaini, L.; Daoudi, E.; Rhazi, M.; Boughaleb, Y.; El Mhammedi, M. A.; Migalska-Zalas, A.; Bakasse, M.

2014-07-01

Chitin, extracted primarily from exoskeleton shellfish, is one of the most abundant biopolymer in the world. It is estimated to be produced annually almost as much as cellulose. The development of fishing activities in Morocco (coastline of 3500 km on both the Atlantic and the Mediterranean) induced an important fish industry waste. The aim of this work is to recover chitin, extracted from shellfish waste, and chitosan, produced by deacetylation of chitin, in the adsorption of organic pesticide 2,4-dichlorophenoxyacetate (2,4-D). The chitosan samples were prepared from chitin from crustacean shells. The chitin deacetylation was carried out in aqueous sodium hydroxide. Characterization of chitin and chitosan was performed by infrared spectroscopy, nuclear magnetic resonance and theoretical calculation of UV-Vis spectra and optical parameters. Analysis of theoretical spectra shows a substantial sensitivity to the hydroxyl and amino groups. The presented hydroxyl group in chitin determines the conformation of the molecule and also the stereochemistry of chemical reactions and kinetics. The presence of functional groups causes the substantial changes of both absorption spectra as well as permanent dipole moment. The adsorption of 2,4-D by chitin and chitosan was performed at different pH values, the pesticide-adsorbent contact time and initial pesticide concentration. The adsorption is described by Langmuir-type isotherm and Freundlich-type isotherm. Recovery tests of 2,4-D confirm the initial interest in using chitin and chitosan as a depolluting agent.

Extraction of chitin from red crab shell waste by cofermentation with Lactobacillus paracasei subsp. tolerans KCTC-3074 and Serratia marcescens FS-3.

PubMed

Jung, W J; Jo, G H; Kuk, J H; Kim, K Y; Park, R D

2006-06-01

For one-step extraction of chitin from red crab shell waste, cofermentation with Lactobacillus paracasei subsp. tolerans KCTC-3074, a lactic-acid-producing bacterium, and Serratia marcescens FS-3, a protease-producing bacterium, was conducted. Fermentation with single strain (L. 3074 or FS-3) was also conducted. At day 7, the pH in L. 3074, FS-3, and L. 3074+FS-3 (1:1) treatment decreased from 6.90 to 3.30, 5.88, and 3.48, respectively. Ash content in the residue after fermentation treatment of crab shells in L. 3074 and L. 3074+FS-3 (1:1) treatment drastically decreased from 41.2% to 3.19 and 1.15%, respectively. In L. 3074+FS-3 (1:1) cofermentation, the level of demineralization was the highest value of 97.2%, but the level of deproteinization in the cofermentation was 52.6% at day 7. Protein content in the treatment of FS-3 alone reduced from 22.4 to 3.62%. These results indicate that cofermentation of the shells using the two strains is efficient and applicable for the one-step extraction of crude chitin from red crab shell waste.

In vitro bioconversion of chitin to pyruvate with thermophilic enzymes.

PubMed

Honda, Kohsuke; Kimura, Keisuke; Ninh, Pham Huynh; Taniguchi, Hironori; Okano, Kenji; Ohtake, Hisao

2017-09-01

Chitin is the second most abundant organic compound on the planet and thus has been regarded as an alternative resource to petroleum feedstocks. One of the key challenges in the biological conversion of biomass-derived polysaccharides, such as cellulose and chitin, is to close the gap between optimum temperatures for enzymatic saccharification and microbial fermentation and to implement them in a single bioreactor. To address this issue, in the present study, we aimed to perform an in vitro, one-pot bioconversion of chitin to pyruvate, which is a precursor of a wide range of useful metabolites. Twelve thermophilic enzymes, including that for NAD + regeneration, were heterologously produced in Escherichia coli and semi-purified by heat treatment of the crude extract of recombinant cells. When the experimentally decided concentrations of enzymes were incubated with 0.5 mg mL -1 colloidal chitin (equivalent to 2.5 mM N-acetylglucosamine unit) and an adequate set of cofactors at 70°C, 0.62 mM pyruvate was produced in 5 h. Despite the use of a cofactor-balanced pathway, determination of the pool sizes of cofactors showed a rapid decrease in ATP concentration, most probably due to the thermally stable ATP-degrading enzyme(s) derived from the host cell. Integration of an additional enzyme set of thermophilic adenylate kinase and polyphosphate kinase led to the deceleration of ATP degradation, and the final product titer was improved to 2.1 mM. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Endoplasmic reticulum localized PerA is required for cell wall integrity, azole drug resistance, and virulence in Aspergillus fumigatus

PubMed Central

Chung, Dawoon; Thammahong, Arsa; Shepardson, Kelly M.; Blosser, Sara J.; Cramer, Robert A.

2014-01-01

Summary GPI-anchoring is a universal and critical post-translational protein modification in eukaryotes. In fungi, many cell wall proteins are GPI-anchored, and disruption of GPI-anchored proteins impairs cell wall integrity. After being synthesized and attached to target proteins, GPI anchors undergo modification on lipid moieties. In spite of its importance for GPI-anchored protein functions, our current knowledge of GPI lipid remodeling in pathogenic fungi is limited. In this study, we characterized the role of a putative GPI lipid remodeling protein, designated PerA, in the human pathogenic fungus Aspergillus fumigatus. PerA localizes to the endoplasmic reticulum and loss of PerA leads to striking defects in cell wall integrity. A perA null mutant has decreased conidia production, increased susceptibility to triazole antifungal drugs, and is avirulent in a murine model of invasive pulmonary aspergillosis. Interestingly, loss of PerA increases exposure of β-glucan and chitin content on the hyphal cell surface, but diminished TNF production by bone marrow derived macrophages relative to wild type. Given the structural specificity of fungal GPI-anchors, which is different from humans, understanding GPI lipid remodeling and PerA function in A. fumigatus is a promising research direction to uncover a new fungal specific antifungal drug target. PMID:24779420

On the function of chitin synthase extracellular domains in biomineralization.

PubMed

Weiss, Ingrid M; Lüke, Florian; Eichner, Norbert; Guth, Christina; Clausen-Schaumann, Hauke

2013-08-01

Molluscs with various shell architectures evolved around 542-525 million years ago, as part of a larger phenomenon related to the diversification of metazoan phyla. Molluscs deposit minerals in a chitin matrix. The mollusc chitin is synthesized by transmembrane enzymes that contain several unique extracellular domains. Here we investigate the assembly mechanism of the chitin synthase Ar-CS1 via its extracellular domain ArCS1_E22. The corresponding transmembrane protein ArCS1_E22TM accumulates in membrane fractions of the expression host Dictyostelium discoideum. Soluble recombinant ArCS1_E22 proteins can be purified as monomers only at basic pH. According to confocal fluorescence microscopy experiments, immunolabeled ArCS1_E22 proteins adsorb preferably to aragonitic nacre platelets at pH 7.75. At pH 8.2 or pH 9.0 the fluorescence signal is less intense, indicating that protein-mineral interaction is reduced with increasing pH. Furthermore, ArCS1_E22 forms regular nanostructures on cationic substrates as revealed by atomic force microscopy (AFM) experiments on modified mica cleavage planes. These experiments suggest that the extracellular domain ArCS1_E22 is involved in regulating the multiple enzyme activities of Ar-CS1 such as chitin synthesis and myosin movements by interaction with mineral surfaces and eventually by protein assembly. The protein complexes could locally probe the status of mineralization according to pH unless ions and pCO2 are balanced with suitable buffer substances. Taking into account that the intact enzyme could act as a force sensor, the results presented here provide further evidence that shell formation is coordinated physiologically with precise adjustment of cellular activities to the structure, topography and stiffness at the mineralizing interface. Copyright © 2013 Elsevier Inc. All rights reserved.

Glucose-Specific Enzyme IIA of the Phosphoenolpyruvate:Carbohydrate Phosphotransferase System Modulates Chitin Signaling Pathways in Vibrio cholerae.

PubMed

Yamamoto, Shouji; Ohnishi, Makoto

2017-09-15

In Vibrio cholerae , the genes required for chitin utilization and natural competence are governed by the chitin-responsive two-component system (TCS) sensor kinase ChiS. In the classical TCS paradigm, a sensor kinase specifically phosphorylates a cognate response regulator to activate gene expression. However, our previous genetic study suggested that ChiS stimulates the non-TCS transcriptional regulator TfoS by using mechanisms distinct from classical phosphorylation reactions (S. Yamamoto, J. Mitobe, T. Ishikawa, S. N. Wai, M. Ohnishi, H. Watanabe, and H. Izumiya, Mol Microbiol 91:326-347, 2014, https://doi.org/10.1111/mmi.12462). TfoS specifically activates the transcription of tfoR , encoding a small regulatory RNA essential for competence gene expression. Whether ChiS and TfoS interact directly remains unknown. To determine if other factors mediate the communication between ChiS and TfoS, we isolated transposon mutants that turned off tfoR :: lacZ expression but possessed intact chiS and tfoS genes. We demonstrated an unexpected association of chitin-induced signaling pathways with the glucose-specific enzyme IIA (EIIA glc ) of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) for carbohydrate uptake and catabolite control of gene expression. Genetic and physiological analyses revealed that dephosphorylated EIIA glc inactivated natural competence and tfoR transcription. Chitin-induced expression of the chb operon, which is required for chitin transport and catabolism, was also repressed by dephosphorylated EIIA glc Furthermore, the regulation of tfoR and chb expression by EIIA glc was dependent on ChiS and intracellular levels of ChiS were not affected by disruption of the gene encoding EIIA glc These results define a previously unknown connection between the PTS and chitin signaling pathways in V. cholerae and suggest a strategy whereby this bacterium can physiologically adapt to the existing nutrient status. IMPORTANCE The EIIA glc

Fourier Transform Infrared Spectroscopic Imaging-Derived Collagen Content and Maturity Correlates with Stress in the Aortic Wall of Abdominal Aortic Aneurysm Patients.

PubMed

Cheheltani, Rabee; Pichamuthu, Joseph E; Rao, Jayashree; Weinbaum, Justin S; Kiani, Mohammad F; Vorp, David A; Pleshko, Nancy

2017-03-01

Abdominal aortic aneurysm (AAA) is a degenerative disease of the aorta characterized by severe disruption of the structural integrity of the aortic wall and its major molecular constituents. From the early stages of disease, elastin in the aorta becomes highly degraded and is replaced by collagen. Questions persist as to the contribution of collagen content, quality and maturity to the potential for rupture. Here, using our recently developed Fourier transform infrared imaging spectroscopy (FT-IRIS) method, we quantified collagen content and maturity in the wall of AAA tissues in pairs of specimens with different wall stresses. CT scans of AAAs from 12 patients were used to create finite element models to estimate stress in different regions of tissue. Each patient underwent elective repair of the AAA, and two segments of the AAA tissues from anatomic regions more proximal or distal with different wall stresses were evaluated by histology and FT-IRIS after excision. For each patient, collagen content was generally greater in the tissue location with lower wall stress, which corresponded to the more distal anatomic regions. The wall stress/collagen ratio was greater in the higher stress region compared to the lower stress region (1.01 ± 1.09 vs. 0.55 ± 0.084, p = 0.02). The higher stress region also corresponded to the location with reduced intraluminal thrombus thickness. Further, collagen maturity tended to decrease with increased collagen content (p = 0.068, R = 0.38). Together, these results suggest that an increase in less mature collagen content in AAA patients does not effectively compensate for the loss of elastin in the aortic wall, and results in a reduced capability to endure wall stresses.

Yeast casein kinase 2 governs morphology, biofilm formation, cell wall integrity, and host cell damage of Candida albicans

PubMed Central

Irrizary, Jihyun; Liboro, Karl; Bogarin, Thania; Macias, Marlene; Eivers, Edward; Porter, Edith; Filler, Scott G.

2017-01-01

The regulatory networks governing morphogenesis of a pleomorphic fungus, Candida albicans are extremely complex and remain to be completely elucidated. This study investigated the function of C. albicans yeast casein kinase 2 (CaYck2p). The yck2Δ/yck2Δ strain displayed constitutive pseudohyphae in both yeast and hyphal growth conditions, and formed enhanced biofilm under non-biofilm inducing condition. This finding was further supported by gene expression analysis of the yck2Δ/yck2Δ strain which showed significant upregulation of UME6, a key transcriptional regulator of hyphal transition and biofilm formation, and cell wall protein genes ALS3, HWP1, and SUN41, all of which are associated with morphogenesis and biofilm architecture. The yck2Δ/yck2Δ strain was hypersensitive to cell wall damaging agents and had increased compensatory chitin deposition in the cell wall accompanied by an upregulation of the expression of the chitin synthase genes, CHS2, CHS3, and CHS8. Absence of CaYck2p also affected fungal-host interaction; the yck2Δ/yck2Δ strain had significantly reduced ability to damage host cells. However, the yck2Δ/yck2Δ strain had wild-type susceptibility to cyclosporine and FK506, suggesting that CaYck2p functions independently from the Ca+/calcineurin pathway. Thus, in C. albicans, Yck2p is a multifunctional kinase that governs morphogenesis, biofilm formation, cell wall integrity, and host cell interactions. PMID:29107946

Yeast casein kinase 2 governs morphology, biofilm formation, cell wall integrity, and host cell damage of Candida albicans.

PubMed

Jung, Sook-In; Rodriguez, Natalie; Irrizary, Jihyun; Liboro, Karl; Bogarin, Thania; Macias, Marlene; Eivers, Edward; Porter, Edith; Filler, Scott G; Park, Hyunsook

2017-01-01

The regulatory networks governing morphogenesis of a pleomorphic fungus, Candida albicans are extremely complex and remain to be completely elucidated. This study investigated the function of C. albicans yeast casein kinase 2 (CaYck2p). The yck2Δ/yck2Δ strain displayed constitutive pseudohyphae in both yeast and hyphal growth conditions, and formed enhanced biofilm under non-biofilm inducing condition. This finding was further supported by gene expression analysis of the yck2Δ/yck2Δ strain which showed significant upregulation of UME6, a key transcriptional regulator of hyphal transition and biofilm formation, and cell wall protein genes ALS3, HWP1, and SUN41, all of which are associated with morphogenesis and biofilm architecture. The yck2Δ/yck2Δ strain was hypersensitive to cell wall damaging agents and had increased compensatory chitin deposition in the cell wall accompanied by an upregulation of the expression of the chitin synthase genes, CHS2, CHS3, and CHS8. Absence of CaYck2p also affected fungal-host interaction; the yck2Δ/yck2Δ strain had significantly reduced ability to damage host cells. However, the yck2Δ/yck2Δ strain had wild-type susceptibility to cyclosporine and FK506, suggesting that CaYck2p functions independently from the Ca+/calcineurin pathway. Thus, in C. albicans, Yck2p is a multifunctional kinase that governs morphogenesis, biofilm formation, cell wall integrity, and host cell interactions.

Future questions in insect chitin biology: A microreview.

PubMed

Muthukrishnan, Subbaratnam; Arakane, Yasuyuki; Yang, Qing; Zhang, Chuan-Xi; Zhang, Jianzhen; Zhang, Wenqing; Moussian, Bernard

2018-06-01

This microreview stems from the Second Symposium on Insect Molecular Toxicology and Chitin Metabolism held at Shanxi University in Taiyuan, China (June 27 to 30, 2017) at the institute for Applied Biology headed by Professor Enbo Ma and Professor Jianzhen Zhang. © 2018 Wiley Periodicals, Inc.

Chitin biological absorbable catheters bridging sural nerve grafts transplanted into sciatic nerve defects promote nerve regeneration.

PubMed

Wang, Zhi-Yong; Wang, Jian-Wei; Qin, Li-Hua; Zhang, Wei-Guang; Zhang, Pei-Xun; Jiang, Bao-Guo

2018-06-01

To investigate the efficacy of chitin biological absorbable catheters in a rat model of autologous nerve transplantation. A segment of sciatic nerve was removed to produce a sciatic nerve defect, and the sural nerve was cut from the ipsilateral leg and used as a graft to bridge the defect, with or without use of a chitin biological absorbable catheter surrounding the graft. The number and morphology of regenerating myelinated fibers, nerve conduction velocity, nerve function index, triceps surae muscle morphology, and sensory function were evaluated at 9 and 12 months after surgery. All of the above parameters were improved in rats in which the nerve graft was bridged with chitin biological absorbable catheters compared with rats without catheters. The results of this study indicate that use of chitin biological absorbable catheters to surround sural nerve grafts bridging sciatic nerve defects promotes recovery of structural, motor, and sensory function and improves muscle fiber morphology. © 2018 John Wiley & Sons Ltd.

Effect of Chitin Isolated from Crustaceans and Cephalopods on Denaturation of Fish Myofibrillar Protein and the State of Water during Frozen Storage

NASA Astrophysics Data System (ADS)

Yamashita, Yasumitsu; Zhang, Nong; Nozaki, Yukinori

The effect of chitin hydrolysate made from shell of crustaceans and cartilage of cephalopods on the denaturation and the state of water of lizard fish myofibrillar protein (Mf) during frozen storage at -250°C for 120 days were investigated. 5.0% chitin hydrolysate (dried matter) added Mf samples were frozen at -25°C and storage for 120 days, and the change of inactivation of Mf Ca-ATPase and the change of unfrozen water in Mf were examined during the frozen storage. The decrease of Mf Ca-ATPase during frozen storage were slow by addition of chitin hydrolysate. The amount of unfrozen water in Mf were increased by addition of chitin hydrolysate, and decreaced gradually during frozen storage. On the other hand, the amount of unfrozen water of the control were decreaced suddenly during frozen storage. Above results suggest that chitin hydrolysate has cryoprotective effect on Mf. It is guessed that the mechanism of cryoprotective effect of chitin hydrolysate may be caused by an interaction between hydration sphere of Mf and equatorial OH groups in the molecular structure of chitin hydrolysate.

Traffic of chitin synthase 1 (CHS-1) to the Spitzenkörper and developing septa in hyphae of Neurospora crassa: actin dependence and evidence of distinct microvesicle populations.

PubMed

Sánchez-León, Eddy; Verdín, Jorge; Freitag, Michael; Roberson, Robert W; Bartnicki-Garcia, Salomon; Riquelme, Meritxell

2011-05-01

We describe the subcellular location of chitin synthase 1 (CHS-1), one of seven chitin synthases in Neurospora crassa. Laser scanning confocal microscopy of growing hyphae showed CHS-1-green fluorescent protein (GFP) localized conspicuously in regions of active wall synthesis, namely, the core of the Spitzenkörper (Spk), the apical cell surface, and developing septa. It was also present in numerous fine particles throughout the cytoplasm plus some large vacuoles in distal hyphal regions. Although the same general subcellular distribution was observed previously for CHS-3 and CHS-6, they did not fully colocalize. Dual labeling showed that the three different chitin synthases were contained in different vesicular compartments, suggesting the existence of a different subpopulation of chitosomes for each CHS. CHS-1-GFP persisted in the Spk during hyphal elongation but disappeared from the septum after its development was completed. Wide-field fluorescence microscopy and total internal reflection fluorescence microscopy revealed subapical clouds of particles, suggestive of chitosomes moving continuously toward the Spk. Benomyl had no effect on CHS-1-GFP localization, indicating that microtubules are not strictly required for CHS trafficking to the hyphal apex. Conversely, actin inhibitors caused severe mislocalization of CHS-1-GFP, indicating that actin plays a major role in the orderly traffic and localization of CHS-1 at the apex.

Emerging Biomedical Applications of Nano-Chitins and Nano-Chitosans Obtained via Advanced Eco-Friendly Technologies from Marine Resources

PubMed Central

Muzzarelli, Riccardo A. A.; El Mehtedi, Mohamad; Mattioli-Belmonte, Monica

2014-01-01

The present review article is intended to direct attention to the technological advances made in the 2010–2014 quinquennium for the isolation and manufacture of nanofibrillar chitin and chitosan. Otherwise called nanocrystals or whiskers, n-chitin and n-chitosan are obtained either by mechanical chitin disassembly and fibrillation optionally assisted by sonication, or by e-spinning of solutions of polysaccharides often accompanied by poly(ethylene oxide) or poly(caprolactone). The biomedical areas where n-chitin may find applications include hemostasis and wound healing, regeneration of tissues such as joints and bones, cell culture, antimicrobial agents, and dermal protection. The biomedical applications of n-chitosan include epithelial tissue regeneration, bone and dental tissue regeneration, as well as protection against bacteria, fungi and viruses. It has been found that the nano size enhances the performances of chitins and chitosans in all cases considered, with no exceptions. Biotechnological approaches will boost the applications of the said safe, eco-friendly and benign nanomaterials not only in these fields, but also for biosensors and in targeted drug delivery areas. PMID:25415349

Implementation of a repeated fed-batch process for the production of chitin-glucan complex by Komagataella pastoris.

PubMed

Farinha, Inês; Freitas, Filomena; Reis, Maria A M

2017-07-25

The yeast Komagataella pastoris was cultivated under different fed-batch strategies for the production of chitin-glucan complex (CGC), a co-polymer of chitin and β-glucan. The tested fed-batch strategies included DO-stat mode, predefined feeding profile and repeated fed-batch operation. Although high cell dry mass and high CGC production were obtained under the tested DO-stat strategy in a 94h cultivation (159 and 29g/L, respectively), the overall biomass and CGC productivities were low (41 and 7.4g/Lday, respectively). Cultivation with a predefined profile significantly improved both biomass and CGC volumetric productivity (87 and 10.8g/Lday, respectively). Hence, this strategy was used to implement a repeated fed-batch process comprising 7 consecutive cycles. A daily production of 119-126g/L of biomass with a CGC content of 11-16wt% was obtained, thus proving this cultivation strategy is adequate to reach a high CGC productivity that ranged between 11 and 18g/Lday. The process was stable and reproducible in terms of CGC productivity and polymer composition, making it a promising strategy for further process development. Copyright © 2016 Elsevier B.V. All rights reserved.

A transcriptional regulator linking quorum sensing and chitin induction to render Vibrio cholerae naturally transformable

PubMed Central

Lo Scrudato, Mirella; Blokesch, Melanie

2013-01-01

The human pathogen Vibrio cholerae is an aquatic bacterium associated with zooplankton and their chitinous exoskeletons. On chitinous surfaces, V. cholerae initiates a developmental programme, known as natural competence, to mediate transformation, which is a mode of horizontal gene transfer. Competence facilitates the uptake of free DNA and recombination into the bacterial genome. Recent studies have indicated that chitin surfaces are required, but not sufficient to induce competence. Two additional regulatory pathways, i.e. catabolite repression and quorum sensing (QS), are components of the regulatory network that controls natural competence in V. cholerae. In this study, we investigated the link between chitin induction and QS. We show that the major regulators of these two pathways, TfoX and HapR, are both involved in the activation of a gene encoding a transcriptional regulator of the LuxR-type family, which we named QS and TfoX-dependent regulator (QstR). We demonstrate that HapR binds the promoter of qstR in a site-specific manner, indicating a role for HapR as an activator of qstR. In addition, epistasis experiments indicate that QstR compensates for the absence of HapR. We also provide evidence that QstR is required for the proper expression of a small but essential subset of competence genes and propose a new regulatory model in which QstR links chitin-induced TfoX activity with QS. PMID:23382174

Eco-Friendly Extraction of Biopolymer Chitin and Carotenoids from Shrimp Waste

NASA Astrophysics Data System (ADS)

Prameela, K.; Venkatesh, K.; Divya vani, K.; Sudesh Kumar, E.; Mohan, CH Murali

2017-08-01

Astaxanthin a nutraceutical and chitin a natural biopolymer present in shrimp waste. In current chemical extraction methods HCl and NaOH are used for extraction and these chemicals are introduced into aquatic ecosystems are spoiling aquatic flora and fauna, pollute the environment and destroy astaxanthin. Lactobacillus species were isolated from gut of Solenocera melantho and characterized phenotypically and genotypically. Initial screening experiments have shown to be an effective and identified as Lactobacillus plantaram based on morphological, biochemical characteristics and molecular analysis. Efficiency of fermentation has shown with good yield of astaxanthin and recovery of chitin. Hence this alternative microbial process is having advantage than existing hazardous, non-economical chemical process.

Enzymatic production of defined chitosan oligomers with a specific pattern of acetylation using a combination of chitin oligosaccharide deacetylases

NASA Astrophysics Data System (ADS)

Hamer, Stefanie Nicole; Cord-Landwehr, Stefan; Biarnés, Xevi; Planas, Antoni; Waegeman, Hendrik; Moerschbacher, Bruno Maria; Kolkenbrock, Stephan

2015-03-01

Chitin and chitosan oligomers have diverse biological activities with potentially valuable applications in fields like medicine, cosmetics, or agriculture. These properties may depend not only on the degrees of polymerization and acetylation, but also on a specific pattern of acetylation (PA) that cannot be controlled when the oligomers are produced by chemical hydrolysis. To determine the influence of the PA on the biological activities, defined chitosan oligomers in sufficient amounts are needed. Chitosan oligomers with specific PA can be produced by enzymatic deacetylation of chitin oligomers, but the diversity is limited by the low number of chitin deacetylases available. We have produced specific chitosan oligomers which are deacetylated at the first two units starting from the non-reducing end by the combined use of two different chitin deacetylases, namely NodB from Rhizobium sp. GRH2 that deacetylates the first unit and COD from Vibrio cholerae that deacetylates the second unit starting from the non-reducing end. Both chitin deacetylases accept the product of each other resulting in production of chitosan oligomers with a novel and defined PA. When extended to further chitin deacetylases, this approach has the potential to yield a large range of novel chitosan oligomers with a fully defined architecture.

Ethylene-responsive element-binding factor 5, ERF5, is involved in chitin-induced innate immunity response.

PubMed

Son, Geon Hui; Wan, Jinrong; Kim, Hye Jin; Nguyen, Xuan Canh; Chung, Woo Sik; Hong, Jong Chan; Stacey, Gary

2012-01-01

Our recent work demonstrated that chitin treatment modulated the expression of 118 transcription factor (TF) genes in Arabidopsis. To investigate the potential roles of these TF in chitin signaling and plant defense, we initiated an interaction study among these TF proteins, as well as two chitin-activated mitogen-activated protein kinases (MPK3 and MPK6), using a yeast two-hybrid system. This study revealed interactions among the following proteins: three ethylene-responsive element-binding factors (ERF), five WRKY transcription factors, one scarecrow-like (SCL), and the two MPK, in addition to many other interactions, reflecting a complex TF interaction network. Most of these interactions were subsequently validated by other methods, such as pull-down and in planta bimolecular fluorescence complementation assays. The key node ERF5 was shown to interact with multiple proteins in the network, such as ERF6, ERF8, and SCL13, as well as MPK3 and MPK6. Interestingly, ERF5 appeared to negatively regulate chitin signaling and plant defense against the fungal pathogen Alternaria brassicicola and positively regulate salicylic acid signaling and plant defense against the bacterial pathogen Pseudomonas syringae pv. tomato DC3000. Therefore, ERF5 may play an important role in plant innate immunity, likely through coordinating chitin and other defense pathways in plants in response to different pathogens.

Effects of Chitin and Contact Insecticide Complexes on Rove Beetles in Commercial Orchards

PubMed Central

Balog, A.; Ferencz, L.; Hartel, T.

2011-01-01

A five-year research project was performed to explore the potential effects of contact insecticide applications on the change of abundance and species richness of predatory rove beetles (Coleoptera: Staphylinidae) in conventionally managed orchards. Twelve blocks of nine orchards were used for this study in Central Europe. High sensitivity atomic force microscopic examination was carried out for chitin structure analyses as well as computer simulation for steric energy calculation between insecticides and chitin. The species richness of rove beetles in orchards was relatively high after insecticide application. Comparing the mean abundance before and after insecticide application, a higher value was observed before spraying with alphacypermethrin and lambda-cyhalothrin, and a lower value was observed in the cases of diflubenzuron, malathion, lufenuron, and phosalone. The species richness was higher only before chlorpyrifos-methyl application. There was a negative correlation between abundance and stability value of chitin-insecticides, persistence time, and soil absorption coefficients. Positive correlation was observed with lipo- and water solubility. PMID:21870981

Chitin/clay microspheres with hierarchical architecture for highly efficient removal of organic dyes.

PubMed

Xu, Rui; Mao, Jie; Peng, Na; Luo, Xiaogang; Chang, Chunyu

2018-05-15

Numerous adsorbents have been reported for efficient removal of dye from water, but the high cost raw materials and complicated fabrication process limit their practical applications. Herein, novel nanocomposite microspheres were fabricated from chitin and clay by a simple thermally induced sol-gel transition. Clay nanosheets were uniformly embedded in a nanofiber weaved chitin microsphere matrix, leading to their hierarchical architecture. Benefiting from this unique structure, microspheres could efficiently remove methylene blue (MB) through a spontaneous physic-sorption process which fit well with pseudo-second-order and Langmuir isotherm models. The maximal values of adsorption capability obtained by calculation and experiment were 152.2 and 156.7 mg g -1 , respectively. Chitin/clay microspheres (CCM2) could remove 99.99% MB from its aqueous solution (10 mg g -1 ) within 20 min. These findings provide insight into a new strategy for fabrication of dye adsorbents with hierarchical structure from low cost raw materials. Copyright © 2018 Elsevier Ltd. All rights reserved.

Curcumin loaded chitin nanogels for skin cancer treatment via the transdermal route

NASA Astrophysics Data System (ADS)

Mangalathillam, Sabitha; Rejinold, N. Sanoj; Nair, Amrita; Lakshmanan, Vinoth-Kumar; Nair, Shantikumar V.; Jayakumar, Rangasamy

2011-12-01

In this study, curcumin loaded chitin nanogels (CCNGs) were developed using biocompatible and biodegradable chitin with an anticancer curcumin drug. Chitin, as well as curcumin, is insoluble in water. However, the developed CCNGs form a very good and stable dispersion in water. The CCNGs were analyzed by DLS, SEM and FTIR and showed spherical particles in a size range of 70-80 nm. The CCNGs showed higher release at acidic pH compared to neutral pH. The cytotoxicity of the nanogels were analyzed on human dermal fibroblast cells (HDF) and A375 (human melanoma) cell lines and the results show that CCNGs have specific toxicity on melanoma in a concentration range of 0.1-1.0 mg mL-1, but less toxicity towards HDF cells. The confocal analysis confirmed the uptake of CCNGs by A375. The apoptotic effect of CCNGs was analyzed by a flow-cytometric assay and the results indicate that CCNGs at the higher concentration of the cytotoxic range showed comparable apoptosis as the control curcumin, in which there was negligible apoptosis induced by the control chitin nanogels. The CCNGs showed a 4-fold increase in steady state transdermal flux of curcumin as compared to that of control curcumin solution. The histopathology studies of the porcine skin samples treated with the prepared materials showed loosening of the horny layer of the epidermis, facilitating penetration with no observed signs of inflammation. These results suggest that the formulated CCNGs offer specific advantage for the treatment of melanoma, the most common and serious type of skin cancer, by effective transdermal penetration.

Curcumin loaded chitin nanogels for skin cancer treatment via the transdermal route.

PubMed

Mangalathillam, Sabitha; Rejinold, N Sanoj; Nair, Amrita; Lakshmanan, Vinoth-Kumar; Nair, Shantikumar V; Jayakumar, Rangasamy

2012-01-07

In this study, curcumin loaded chitin nanogels (CCNGs) were developed using biocompatible and biodegradable chitin with an anticancer curcumin drug. Chitin, as well as curcumin, is insoluble in water. However, the developed CCNGs form a very good and stable dispersion in water. The CCNGs were analyzed by DLS, SEM and FTIR and showed spherical particles in a size range of 70-80 nm. The CCNGs showed higher release at acidic pH compared to neutral pH. The cytotoxicity of the nanogels were analyzed on human dermal fibroblast cells (HDF) and A375 (human melanoma) cell lines and the results show that CCNGs have specific toxicity on melanoma in a concentration range of 0.1-1.0 mg mL(-1), but less toxicity towards HDF cells. The confocal analysis confirmed the uptake of CCNGs by A375. The apoptotic effect of CCNGs was analyzed by a flow-cytometric assay and the results indicate that CCNGs at the higher concentration of the cytotoxic range showed comparable apoptosis as the control curcumin, in which there was negligible apoptosis induced by the control chitin nanogels. The CCNGs showed a 4-fold increase in steady state transdermal flux of curcumin as compared to that of control curcumin solution. The histopathology studies of the porcine skin samples treated with the prepared materials showed loosening of the horny layer of the epidermis, facilitating penetration with no observed signs of inflammation. These results suggest that the formulated CCNGs offer specific advantage for the treatment of melanoma, the most common and serious type of skin cancer, by effective transdermal penetration.

Chitin, Chitosan, and Glycated Chitosan Regulate Immune Responses: The Novel Adjuvants for Cancer Vaccine

PubMed Central

Li, Xiaosong; Min, Min; Du, Nan; Gu, Ying; Hode, Tomas; Naylor, Mark; Chen, Dianjun; Nordquist, Robert E.; Chen, Wei R.

2013-01-01

With the development of cancer immunotherapy, cancer vaccine has become a novel modality for cancer treatment, and the important role of adjuvant has been realized recently. Chitin, chitosan, and their derivatives have shown their advantages as adjuvants for cancer vaccine. In this paper, the adjuvant properties of chitin and chitosan were discussed, and some detailed information about glycated chitosan and chitosan nanoparticles was also presented to illustrate the trend for future development. PMID:23533454

Cell Wall Remodeling Enzymes Modulate Fungal Cell Wall Elasticity and Osmotic Stress Resistance.

PubMed

Ene, Iuliana V; Walker, Louise A; Schiavone, Marion; Lee, Keunsook K; Martin-Yken, Hélène; Dague, Etienne; Gow, Neil A R; Munro, Carol A; Brown, Alistair J P

2015-07-28

The fungal cell wall confers cell morphology and protection against environmental insults. For fungal pathogens, the cell wall is a key immunological modulator and an ideal therapeutic target. Yeast cell walls possess an inner matrix of interlinked β-glucan and chitin that is thought to provide tensile strength and rigidity. Yeast cells remodel their walls over time in response to environmental change, a process controlled by evolutionarily conserved stress (Hog1) and cell integrity (Mkc1, Cek1) signaling pathways. These mitogen-activated protein kinase (MAPK) pathways modulate cell wall gene expression, leading to the construction of a new, modified cell wall. We show that the cell wall is not rigid but elastic, displaying rapid structural realignments that impact survival following osmotic shock. Lactate-grown Candida albicans cells are more resistant to hyperosmotic shock than glucose-grown cells. We show that this elevated resistance is not dependent on Hog1 or Mkc1 signaling and that most cell death occurs within 10 min of osmotic shock. Sudden decreases in cell volume drive rapid increases in cell wall thickness. The elevated stress resistance of lactate-grown cells correlates with reduced cell wall elasticity, reflected in slower changes in cell volume following hyperosmotic shock. The cell wall elasticity of lactate-grown cells is increased by a triple mutation that inactivates the Crh family of cell wall cross-linking enzymes, leading to increased sensitivity to hyperosmotic shock. Overexpressing Crh family members in glucose-grown cells reduces cell wall elasticity, providing partial protection against hyperosmotic shock. These changes correlate with structural realignment of the cell wall and with the ability of cells to withstand osmotic shock. The C. albicans cell wall is the first line of defense against external insults, the site of immune recognition by the host, and an attractive target for antifungal therapy. Its tensile strength is conferred by

Synthesis and characteristics of chitin and chitosan with the (2-hydroxy-3-trimethylammonium)propyl functionality, and evaluation of their antioxidant activity in vitro.

PubMed

Zhang, Xiao; Geng, Xiaodong; Jiang, Hengjun; Li, Jianrong; Huang, Jianying

2012-06-20

Quaternary amino groups were introduced into chitin and chitosan to obtain O-(2-hydroxy-3-trimethylammonium)propyl chitin (OHT-chitin) and N-(2-hydroxy-3-trimethylammonium)propyl chitosan (NHT-chitosan). They were characterized by FTIR spectra, and GPC. The molecular weight Mw of OHT-chitin and NHT-chitosan were 8986 and 9723 with polydispersity of 1.01 and 1.0 2, respectively. Their antioxidant activities in vitro were further studied. It was found that β-carotene-linoleic acid values of OHT-chitin and NHT-chitosan at 0.8 mg/mL were up to 91% and 96%, while that of chitosan was 40%. Based on photobleaching of α,α-diphenyl-β-picrylhydrazyl (DPPH) at 326 nm, the DPPH inhibitory activity of OHT-chitin and NHT-chitosan was 30.9% and 31.9% at 5 mg/mL, whereas chitosan only gave 4.8%. It was also exhibited that OHT-chitin and NHT-chitosan had better antioxidant activity than chitosan according to the reducing power as well as H2O2 scavenging activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Candida antarctica Lipase B Immobilized onto Chitin Conjugated with POSS® Compounds: Useful Tool for Rapeseed Oil Conversion

PubMed Central

Zdarta, Jakub; Wysokowski, Marcin; Norman, Małgorzata; Kołodziejczak-Radzimska, Agnieszka; Moszyński, Dariusz; Maciejewski, Hieronim; Ehrlich, Hermann; Jesionowski, Teofil

2016-01-01

A new method is proposed for the production of a novel chitin-polyhedral oligomeric silsesquioxanes (POSS) enzyme support. Analysis by such techniques as X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed the effective functionalization of the chitin surface. The resulting hybrid carriers were used in the process of immobilization of the lipase type b from Candida antarctica (CALB). Fourier transform infrared spectroscopy (FTIR) confirmed the effective immobilization of the enzyme. The tests of the catalytic activity showed that the resulting support-biocatalyst systems remain hydrolytically active (retention of the hydrolytic activity up to 87% for the chitin + Methacryl POSS® cage mixture (MPOSS) + CALB after 24 h of the immobilization), as well as represents good thermal and operational stability, and retain over 80% of its activity in a wide range of temperatures (30–60 °C) and pH (6–9). Chitin-POSS-lipase systems were used in the transesterification processes of rapeseed oil at various reaction conditions. Produced systems allowed the total conversion of the oil to fatty acid methyl esters (FAME) and glycerol after 24 h of the process at pH 10 and a temperature 40 °C, while the Methacryl POSS® cage mixture (MPOSS) was used as a chitin-modifying agent. PMID:27657054

Halogenation of microcapsule walls

NASA Technical Reports Server (NTRS)

Davis, T. R.; Schaab, C. K.; Scott, J. C.

1972-01-01

Procedure for halogenation of confining walls of both gelatin and gelatin-phenolic resin capsules is similar to that used for microencapsulation. Ten percent halogen content renders capsule wall nonburning; any higher content enhances flame-retardant properties of selected internal phase material. Halogenation decreases permeability of wall material to encapsulated materials.

Selective Modification of Chitin and Chitosan: En Route to Tailored Oligosaccharides.

PubMed

Carvalho, Luísa C R; Queda, Fausto; Santos, Cátia V Almeida; Marques, M Manuel B

2016-12-19

Chitin and chitosan are attractive biopolymers with enormous structural possibilities for chemical modification, creating platforms for new chemical entities with a broad scope of applications, ranging from material science to medicine. During the last few years, incredible efforts have been dedicated to the regioselective modification of these biopolymers paving the way for improved properties and tailored activities. Herein, the most recent advances in chitin/chitosan regioselective modification, reaction conditions, selectivity, and the impact on its applications are highlighted. Moreover, the recent focus on chitooligosaccharides, their regioselective and chemoselective functionalization, as well as their role in biological studies, including molecular recognition with several biological targets are also covered. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of sub- and supercritical water treatments on the physicochemical properties of crab shell chitin and its enzymatic degradation.

PubMed

Osada, Mitsumasa; Miura, Chika; Nakagawa, Yuko S; Kaihara, Mikio; Nikaido, Mitsuru; Totani, Kazuhide

2015-12-10

This study examined the effects of sub- and supercritical water pretreatments on the physicochemical properties of crab shell α-chitin and its enzymatic degradation to obtain N,N'-diacetylchitobiose (GlcNAc)2. Following sub- and supercritical water pretreatments, the protein in the crab shell was removed and the residue of crab shell contained α-chitin and CaCO3. Prolonged pretreatment led to α-chitin decomposition. The reaction of pure α-chitin in sub- and supercritical water pretreatments was investigated separately; we observed lower mean molecular weight and weaker hydrogen bonds compared with untreated α-chitin. (GlcNAc)2 yields from enzymatic degradation of subcritical (350 °C, 7 min) and supercritical water (400 °C, 2.5 min) pretreated crab shell were 8% and 6%, compared with 0% without any pretreatment. This study shows that sub- and supercritical water pretreatments of crab shell provide to an alternative method to the use of acid and base for decalcification and deproteinization of crab shell required for (GlcNAc)2 production. Copyright © 2015 Elsevier Ltd. All rights reserved.

Tracking developmentally regulated post-synthetic processing of homogalacturonan and chitin using reciprocal oligosaccharide probes.

PubMed

Mravec, Jozef; Kračun, Stjepan K; Rydahl, Maja G; Westereng, Bjørge; Miart, Fabien; Clausen, Mads H; Fangel, Jonatan U; Daugaard, Mathilde; Van Cutsem, Pierre; De Fine Licht, Henrik H; Höfte, Herman; Malinovsky, Frederikke G; Domozych, David S; Willats, William G T

2014-12-01

Polysaccharides are major components of extracellular matrices and are often extensively modified post-synthetically to suit local requirements and developmental programmes. However, our current understanding of the spatiotemporal dynamics and functional significance of these modifications is limited by a lack of suitable molecular tools. Here, we report the development of a novel non-immunological approach for producing highly selective reciprocal oligosaccharide-based probes for chitosan (the product of chitin deacetylation) and for demethylesterified homogalacturonan. Specific reciprocal binding is mediated by the unique stereochemical arrangement of oppositely charged amino and carboxy groups. Conjugation of oligosaccharides to fluorophores or gold nanoparticles enables direct and rapid imaging of homogalacturonan and chitosan with unprecedented precision in diverse plant, fungal and animal systems. We demonstrated their potential for providing new biological insights by using them to study homogalacturonan processing during Arabidopsis thaliana root cap development and by analyzing sites of chitosan deposition in fungal cell walls and arthropod exoskeletons. © 2014. Published by The Company of Biologists Ltd.

Effect of low shear modeled microgravity on phenotypic and central chitin metabolism in the filamentous fungi Aspergillus niger and Penicillium chrysogenum.

PubMed

Sathishkumar, Yesupatham; Velmurugan, Natarajan; Lee, Hyun Mi; Rajagopal, Kalyanaraman; Im, Chan Ki; Lee, Yang Soo

2014-08-01

Phenotypic and genotypic changes in Aspergillus niger and Penicillium chrysogenum, spore forming filamentous fungi, with respect to central chitin metabolism were studied under low shear modeled microgravity, normal gravity and static conditions. Low shear modeled microgravity (LSMMG) response showed a similar spore germination rate with normal gravity and static conditions. Interestingly, high ratio of multiple germ tube formation of A. niger in LSMMG condition was observed. Confocal laser scanning microscopy images of calcofluor flurophore stained A. niger and P. chrysogenum showed no significant variations between different conditions tested. Transmission electron microscopy images revealed number of mitochondria increased in P. chrysogenum in low shear modeled microgravity condition but no stress related-woronin bodies in fungal hyphae were observed. To gain additional insight into the cell wall integrity under different conditions, transcription level of a key gene involved in cell wall integrity gfaA, encoding the glutamine: fructose-6-phosphate amidotransferase enzyme, was evaluated using qRT-PCR. The transcription level showed no variation among different conditions. Overall, the results collectively indicate that the LSMMG has shown no significant stress on spore germination, mycelial growth, cell wall integrity of potentially pathogenic fungi, A. niger and P. chrysogenum.

Expression and characterization of an enhanced recombinant heparinase I with chitin binding domain.

PubMed

Xu, Shuqin; Qiu, Meiling; Zhang, Xuanyue; Chen, Jinghua

2017-12-01

Heparinase I (Hep I) can efficiently depolymerize heparin and heparin sulfate to oligosaccharides or unsaturated disaccharides, which resulted in loss of physiological function such as blood coagulation. In order to realize the immobilization of Hep I on chitin carriers, we cloned Hep I with the chitin binding domain (ChBD) as a chitin-affinity tag, and the Small Ubiquitin-like MOdifier (SUMO) linker as a solvation enhancer in different fusion sequence. DNA and protein gels suggested that 4 kinds of recombinants were successfully constructed and expressed in Escherichia coli (E. coli). And the triple functional heparinases isolated from cell lysate could be efficiently purified by chitin beads. After optimizing fermentation conditions, it gave the specific enzyme activities of 1.88±0.11, 3.69±0.45, 3.44±0.38, and 2.73±0.29IU/mg total proteins for ChBD-Hep I, ChBD-SUMO-Hep I, SUMO-ChBD-Hep I, and ChBD-Hep I-SUMO, respectively, with unfractionated heparin as substrate. The optimal reaction temperature and pH were determined to be 30°C and 7.0 for all the fusion enzymes. ChBD-SUMO-Hep I exhibited the maximum half-life (48min) at 30°C and best thermo-stability under 15-50°C. All the fusion enzymes showed broad pH-stability in the range of 5.4-9.0. Copyright © 2017 Elsevier B.V. All rights reserved.

A Mitogen-Activated Protein Kinase Tmk3 Participates in High Osmolarity Resistance, Cell Wall Integrity Maintenance and Cellulase Production Regulation in Trichoderma reesei

PubMed Central

Wang, Mingyu; Zhao, Qiushuang; Yang, Jinghua; Jiang, Baojie; Wang, Fangzhong; Liu, Kuimei; Fang, Xu

2013-01-01

The mitogen-activated protein kinase (MAPK) pathways are important signal transduction pathways conserved in essentially all eukaryotes, but haven't been subjected to functional studies in the most important cellulase-producing filamentous fungus Trichoderma reesei. Previous reports suggested the presence of three MAPKs in T. reesei: Tmk1, Tmk2, and Tmk3. By exploring the phenotypic features of T. reesei Δtmk3, we first showed elevated NaCl sensitivity and repressed transcription of genes involved in glycerol/trehalose biosynthesis under higher osmolarity, suggesting Tmk3 participates in high osmolarity resistance via derepression of genes involved in osmotic stabilizer biosynthesis. We also showed significant downregulation of genes encoding chitin synthases and a β-1,3-glucan synthase, decreased chitin content, ‘budded’ hyphal appearance typical to cell wall defective strains, and increased sensitivity to calcofluor white/Congo red in the tmk3 deficient strain, suggesting Tmk3 is involved in cell wall integrity maintenance in T. reesei. We further observed the decrease of cellulase transcription and production in T. reesei Δtmk3 during submerged cultivation, as well as the presence of MAPK phosphorylation sites on known transcription factors involved in cellulase regulation, suggesting Tmk3 is also involved in the regulation of cellulase production. Finally, the expression of cell wall integrity related genes, the expression of cellulase coding genes, cellulase production and biomass accumulation were compared between T. reesei Δtmk3 grown in solid state media and submerged media, showing a strong restoration effect in solid state media from defects resulted from tmk3 deletion. These results showed novel physiological processes that fungal Hog1-type MAPKs are involved in, and present the first experimental investigation of MAPK signaling pathways in T. reesei. Our observations on the restoration effect during solid state cultivation suggest that T. reesei

Effects of Chitin and Its Derivative Chitosan on Postharvest Decay of Fruits: A Review

PubMed Central

Zhang, Hongyin; Li, Renping; Liu, Weimin

2011-01-01

Considerable economic losses to harvested fruits are caused by postharvest fungal decay during transportation and storage, which can be significantly controlled by synthetic fungicides. However, considering public concern over pesticide residues in food and the environment, there is a need for safer alternatives for the control of postharvest decay to substitute synthetic fungicides. As the second most abundant biopolymer renewable source in nature, chitin and its derivative chitosan are widely used in controlling postharvest decay of fruits. This review aims to introduce the effect of chitin and chitosan on postharvest decay in fruits and the possible modes of action involved. We found most of the actions discussed in these researches rest on physiological mechanisms. All of the mechanisms are summarized to lay the groundwork for further studies which should focus on the molecular mechanisms of chitin and chitosan in controlling postharvest decay of fruits. PMID:21541034

3D chitinous scaffolds derived from cultivated marine demosponge Aplysina aerophoba for tissue engineering approaches based on human mesenchymal stromal cells.

PubMed

Mutsenko, Vitalii V; Bazhenov, Vasilii V; Rogulska, Olena; Tarusin, Dmitriy N; Schütz, Kathleen; Brüggemeier, Sophie; Gossla, Elke; Akkineni, Ashwini R; Meißner, Heike; Lode, Anja; Meschke, Stephan; Ehrlich, Andre; Petović, Slavica; Martinović, Rajko; Djurović, Mirko; Stelling, Allison L; Nikulin, Sergey; Rodin, Sergey; Tonevitsky, Alexander; Gelinsky, Michael; Petrenko, Alexander Y; Glasmacher, Birgit; Ehrlich, Hermann

2017-11-01

The recently discovered chitin-based scaffolds derived from poriferans have the necessary prosperities for potential use in tissue engineering. Among the various demosponges of the Verongida order, Aplysina aerophoba is an attractive target for more in-depth investigations, as it is a renewable source of unique 3D microporous chitinous scaffolds. We found these chitinous scaffolds were cytocompatible and supported attachment, growth and proliferation of human mesenchymal stromal cells (hMSCs) in vitro. Cultivation of hMSCs on the scaffolds for 7days resulted in a two-fold increase in their metabolic activity, indicating increased cell numbers. Cells cultured onto chitin scaffolds in differentiation media were able to differentiate into the chondrogenic, adipogenic and osteogenic lineages, respectively. These results indicate A. aerophoba is a novel source of chitin scaffolds to futher hMSCs-based tissue engineering strategies. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced removal of hazardous dye form aqueous solutions and real textile wastewater using bifunctional chitin/lignin biosorbent.

PubMed

Wawrzkiewicz, Monika; Bartczak, Przemysław; Jesionowski, Teofil

2017-06-01

A new biomaterial based on chitin and lignin was prepared and applied for the removal of hazardous dye C.I. Direct Blue 71 (DB71) from aqueous solutions and wastewaters. The dye sorption on the chitin/lignin biosorbent (Ch/L) was examined depending on the initial dye concentration (50-200mg/L), phase contact time (1-1440min), kind of auxiliaries (NaCl, Na 2 SO 4 , anionic surfactant SDS) and their concentrations (1-20g/L salts, 0.1-0.75g/L SDS), initial solution pH as well as temperature (20-50°C). The equilibrium and kinetic characteristics of C.I. Direct Blue 71 uptake by chitin/lignin followed by the Freundlich isotherm model and the pseudo-second order model rather than the Langmuir, Tempkin models, and pseudo-first order model. C.I. Direct Blue 71 adsorption on chitin/lignin was spontaneous (-2.86 to -8.14kJ/mol) and endothermic (60.1kJ/mol). The possibilities of dye elution and reuse by means of the batch method were investigated and as follows the chemical reaction is an inseparable sorption mechanism. Purification of wastewaters containing direct dyes was made with 91% efficiency after 1h of phase contact time. For comparison, data obtained or obtained results in the DB71-chitin (Ch) system were also presented. Copyright © 2017 Elsevier B.V. All rights reserved.

Injectable Shear-Thinning CaSO4/FGF-18-Incorporated Chitin-PLGA Hydrogel Enhances Bone Regeneration in Mice Cranial Bone Defect Model.

PubMed

Sivashanmugam, A; Charoenlarp, Pornkawee; Deepthi, S; Rajendran, Arunkumar; Nair, Shantikumar V; Iseki, Sachiko; Jayakumar, R

2017-12-13

For craniofacial bone regeneration, shear-thinning injectable hydrogels are favored over conventional scaffolds because of their improved defect margin adaptability, easier handling, and ability to be injected manually into deeper tissues. The most accepted method, after autografting, is the use of recombinant human bone morphogenetic protein-2 (BMP-2); however, complications such as interindividual variations, edema, and poor cost-efficiency in supraphysiological doses have been reported. The endogenous synthesis of BMP-2 is desirable, and a molecule which induces this is fibroblast growth factor-18 (FGF-18) because it can upregulate the BMP-2 expression  by supressing noggin. We developed a chitin-poly(lactide-co-glycolide) (PLGA) composite hydrogel by regeneration chemistry and then incorporated CaSO 4 and FGF-18 for this purpose. Rheologically, a 7-fold increase in the elastic modulus was observed in the CaSO 4 -incorporated chitin-PLGA hydrogels as compared to the chitin-PLGA hydrogel. Shear-thinning Herschel-Bulkley fluid nature was observed for both hydrogels. Chitin-PLGA/CaSO 4 gel showed sustained release of FGF-18. In vitro osteogenic differentiation showed an enhanced alkaline phosphatase (ALP) expression in the FGF-18-containing chitin-PLGA/CaSO 4 gel when compared to cells alone. Further, it was confirmed by studying the expression of osteogenic genes [RUNX2, ALP, BMP-2, osteocalcin (OCN), and osteopontin (OPN)], immunofluorescence staining of BMP-2, OCN, and OPN, and alizarin red S staining. Incorporation of FGF-18 in the hydrogel increased the endothelial cell migration. Further, the regeneration potential of the prepared hydrogels was tested in vivo, and longitudinal live animal μ-CT was performed. FGF-18-loaded chitin-PLGA/CaSO 4 showed early and almost complete bone healing in comparison with chitin-PLGA/CaSO 4 , chitin-PLGA/FGF-18, chitin-PLGA, and sham control systems, as confirmed by hematoxylin and eosin and osteoid tetrachrome stainings

Hydrogels based on cellulose and chitin: fabrication, properties, and applications

DOE PAGES

Shen, Xiaoping; Shamshina, Julia L.; Berton, Paula; ...

2015-11-16

A review of the synthesis and applications of renewable, biocompatible, and biodegradable hydrogels made from cellulose, chitin, and some of their derivatives indicates increased attention due to their excellent processability, high absorbency, porosity, bioactivity, and abundant active groups.

Hydrogels based on cellulose and chitin: fabrication, properties, and applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Xiaoping; Shamshina, Julia L.; Berton, Paula

A review of the synthesis and applications of renewable, biocompatible, and biodegradable hydrogels made from cellulose, chitin, and some of their derivatives indicates increased attention due to their excellent processability, high absorbency, porosity, bioactivity, and abundant active groups.

Antioxidant and antimicrobial proprieties of chitin and chitosan extracted from Parapenaeus Longirostris shrimp shell waste.

PubMed

Hafsa, J; Smach, M A; Charfeddine, B; Limem, K; Majdoub, H; Rouatbi, S

2016-01-01

Chitosan, the linear polymer, is produced by alkali deacetylation of chitin (CHI). Recently chitin and chitosan were attracted marked interest due to their biocompatibility, biodegradability and non-toxicity. In this study, chitin was extracted from shrimp shell (Parapenaeus longirostris) and chitosan was deacetylated by classical and ultrasound-assisted method. The identification of functional groups and the determination of degree of deacetylation of chitin (CHI), classical deacetylated chitosan (CDC) and ultrasound-assisted deacetylated chitosan (UDC) were carried through Fourier Transform-Infrared Spectroscopy. Their antimicrobial and antioxidant activity were also investigated. The degree of deacetylation of CHI, CDC and UDC is 33.64%, 73.68% and 83.55%, respectively. Results showed that CHI, CDC and UDC exhibited a good antimicrobial activity against (S. aureus, E. coli, P. aeruginosa, K. pneumonia) and (C. albicans and C. parapsilosis). The scavenging ability of CHI, CDC and UDC on 1,1-diphenyl-2-picrylhydrazyl radicals is ranging from 4.71% to 21.25%, 11.45% to 32.78% and 18.27% to 44.17%, respectively, at the concentrations of 0.25 to 1mg/mL. The inhibition of lipid peroxidation with thiobarbituric acid-reacting substances is ranging from 11.7% to 51.63%, 17.24% to 63.52% and 29.31% to 77.39%, respectively, at varying concentrations of 0.25 to 1mg/mL. The effectiveness of CHI, CDC and UDC is correlated with their degree of deacetylation. The results indicate the possibility of exploiting chitin and chitosan as antimicrobial agent. Copyright © 2015 Académie Nationale de Pharmacie. Published by Elsevier Masson SAS. All rights reserved.

Reinforcement of thermoplastic chitosan hydrogel using chitin whiskers optimized with response surface methodology.

PubMed

Sun, Guohui; Zhang, Xin; Bao, Zixian; Lang, Xuqian; Zhou, Zhongzheng; Li, Yang; Feng, Chao; Chen, Xiguang

2018-06-01

To strengthen the mechanical strength of thermo-sensitive hydroxybutyl chitosan (HBC) hydrogel, chitin whiskers were used as sticker to fabricate reinforced HBC (HBCW) hydrogel by using response surface methodology. Unlike the intrinsic network of HBC hydrogel, HBCW hydrogel showed a laminar shape with firm structure. The preparation condition was optimized by three-factor-three-level Box-Behnken design. The maximum mechanical strength (1011.11 Pa) was achieved at 50 °C, when the concentrations of HBC and chitin whiskers were 5.1 wt% and 2.0 wt%, respectively. The effects of temperature, pH value and NaCl concentration on mechanical strength of HBCW hydrogels were investigated via the oscillatory stress sweeps. The results showed that HBCW hydrogel could reach the maximum stiffness (∼1126 Pa) at 37 °C pH 12.0. Low pH and high salty ions could decrease the stability of hydrogel, while chitin whiskers could increase the stress tolerance and related ruptured strain of HBCW hydrogels. Copyright © 2018. Published by Elsevier Ltd.

In vitro evaluation of paclitaxel loaded amorphous chitin nanoparticles for colon cancer drug delivery.

PubMed

Smitha, K T; Anitha, A; Furuike, T; Tamura, H; Nair, Shantikumar V; Jayakumar, R

2013-04-01

Chitin and its derivatives have been widely used in drug delivery applications due to its biocompatible, biodegradable and non-toxic nature. In this study, we have developed amorphous chitin nanoparticles (150±50 nm) and evaluated its potential as a drug delivery system. Paclitaxel (PTX), a major chemotherapeutic agent was loaded into amorphous chitin nanoparticles (AC NPs) through ionic cross-linking reaction using TPP. The prepared PTX loaded AC NPs had an average diameter of 200±50 nm. Physico-chemical characterization of the prepared nanoparticles was carried out. These nanoparticles were proven to be hemocompatible and in vitro drug release studies showed a sustained release of PTX. Cellular internalization of the NPs was confirmed by fluorescent microscopy as well as by flow cytometry. Anticancer activity studies proved the toxicity of PTX-AC NPs toward colon cancer cells. These preliminary results indicate the potential of PTX-AC NPs in colon cancer drug delivery. Copyright © 2012 Elsevier B.V. All rights reserved.

Chitin-induced activation of immune signaling by the rice receptor CEBiP relies on a unique sandwich-type dimerization

PubMed Central

Hayafune, Masahiro; Berisio, Rita; Marchetti, Roberta; Silipo, Alba; Kayama, Miyu; Desaki, Yoshitake; Arima, Sakiko; Squeglia, Flavia; Ruggiero, Alessia; Tokuyasu, Ken; Molinaro, Antonio; Kaku, Hanae; Shibuya, Naoto

2014-01-01

Perception of microbe-associated molecular patterns (MAMPs) through pattern recognition receptors (PRRs) triggers various defense responses in plants. This MAMP-triggered immunity plays a major role in the plant resistance against various pathogens. To clarify the molecular basis of the specific recognition of chitin oligosaccharides by the rice PRR, CEBiP (chitin-elicitor binding protein), as well as the formation and activation of the receptor complex, biochemical, NMR spectroscopic, and computational studies were performed. Deletion and domain-swapping experiments showed that the central lysine motif in the ectodomain of CEBiP is essential for the binding of chitin oligosaccharides. Epitope mapping by NMR spectroscopy indicated the preferential binding of longer-chain chitin oligosaccharides, such as heptamer-octamer, to CEBiP, and also the importance of N-acetyl groups for the binding. Molecular modeling/docking studies clarified the molecular interaction between CEBiP and chitin oligosaccharides and indicated the importance of Ile122 in the central lysine motif region for ligand binding, a notion supported by site-directed mutagenesis. Based on these results, it was indicated that two CEBiP molecules simultaneously bind to one chitin oligosaccharide from the opposite side, resulting in the dimerization of CEBiP. The model was further supported by the observations that the addition of (GlcNAc)8 induced dimerization of the ectodomain of CEBiP in vitro, and the dimerization and (GlcNAc)8-induced reactive oxygen generation were also inhibited by a unique oligosaccharide, (GlcNβ1,4GlcNAc)4, which is supposed to have N-acetyl groups only on one side of the molecule. Based on these observations, we proposed a hypothetical model for the ligand-induced activation of a receptor complex, involving both CEBiP and Oryza sativa chitin-elicitor receptor kinase-1. PMID:24395781

Solution structure, backbone dynamics and chitin binding of the anti-fungal protein from Streptomyces tendae TU901.

PubMed

Campos-Olivas, R; Hörr, I; Bormann, C; Jung, G; Gronenborn, A M

2001-05-11

AFP1 is a recently discovered anti-fungal, chitin-binding protein from Streptomyces tendae Tü901. Mature AFP1 comprises 86 residues and exhibits limited sequence similarity to the cellulose-binding domains of bacterial cellulases and xylanases. No similarity to the Cys and Gly-rich domains of plant chitin-binding proteins (e.g. agglutinins, lectins, hevein) is observed. AFP1 is the first chitin-binding protein from a bacterium for which anti-fungal activity was shown. Here, we report the three-dimensional solution structure of AFP1, determined by nuclear magnetic resonance spectroscopy. The protein contains two antiparallel beta-sheets (five and four beta-strands each), that pack against each other in a parallel beta-sandwich. This type of architecture is conserved in the functionally related family II of cellulose-binding domains, albeit with different connectivity. A similar fold is also observed in other unrelated proteins (spore coat protein from Myxococcus xanthus, beta-B2 and gamma-B crystallins from Bos taurus, canavalin from Jack bean). AFP1 is therefore classified as a new member of the betagamma-crystallin superfamily. The dynamics of the protein was characterized by NMR using amide 15N relaxation and solvent exchange data. We demonstrate that the protein exhibits an axially symmetric (oblate-like) rotational diffusion tensor whose principal axis coincides to within 15 degrees with that of the inertial tensor. After completion of the present structure of AFP1, an identical fold was reported for a Streptomyces killer toxin-like protein. Based on sequence comparisons and clustering of conserved residues on the protein surface for different cellulose and chitin-binding proteins, we postulate a putative sugar-binding site for AFP1. The inability of the protein to bind short chitin fragments suggests that certain particular architectural features of the solid chitin surface are crucial for the interaction. Copyright 2001 Academic Press.

Cloning of cDNA sequences encoding cowpea (Vigna unguiculata) vicilins: Computational simulations suggest a binding mode of cowpea vicilins to chitin oligomers.

PubMed

Rocha, Antônio J; Sousa, Bruno L; Girão, Matheus S; Barroso-Neto, Ito L; Monteiro-Júnior, José E; Oliveira, José T A; Nagano, Celso S; Carneiro, Rômulo F; Monteiro-Moreira, Ana C O; Rocha, Bruno A M; Freire, Valder N; Grangeiro, Thalles B

2018-05-27

Vicilins are 7S globulins which constitute the major seed storage proteins in leguminous species. Variant vicilins showing differential binding affinities for chitin have been implicated in the resistance and susceptibility of cowpea to the bruchid Callosobruchus maculatus. These proteins are members of the cupin superfamily, which includes a wide variety of enzymes and non-catalytic seed storage proteins. The cupin fold does not share similarity with any known chitin-biding domain. Therefore, it is poorly understood how these storage proteins bind to chitin. In this work, partial cDNA sequences encoding β-vignin, the major component of cowpea vicilins, were obtained from developing seeds. Three-dimensional molecular models of β-vignin showed the characteristic cupin fold and computational simulations revealed that each vicilin trimer contained 3 chitin-binding sites. Interaction models showed that chito-oligosaccharides bound to β-vignin were stabilized mainly by hydrogen bonds, a common structural feature of typical carbohydrate-binding proteins. Furthermore, many of the residues involved in the chitin-binding sites of β-vignin are conserved in other 7S globulins. These results support previous experimental evidences on the ability of vicilin-like proteins from cowpea and other leguminous species to bind in vitro to chitin as well as in vivo to chitinous structures of larval C. maculatus midgut. Copyright © 2018. Published by Elsevier B.V.

Systematic dynamic viscoelasticity measurements for chitin nanofibers prepared with various concentrations, disintegration times, acidities, and crystalline structures.

PubMed

Suenaga, Shin; Osada, Mitsumasa

2018-04-17

Dynamic viscoelasticities were measured for chitin nanofiber (ChNF) dispersions prepared with various concentrations, disintegration times, acidities, and crystalline structures. The 0.05 w/v% dispersions of pH neutral ChNFs continuously exhibited elastic behavior. The 0.05 w/v% dispersions of acidified ChNFs, on the other hand, transitioned from a colloidal dispersion to a critical gel and then exhibited elastic behavior with increasing ChNF concentration. A double-logarithmic chart of the concentration vs. the storage modulus was prepared and indicated the fractal dimension and the nanostructure in the dispersion. The results determined that the neutral α- and β-ChNFs were dispersed but showed some remaining aggregations and that the acidified β-ChNFs were completely individualized. In addition, the α-chitin steadily disintegrated with increasing disintegration time, and the aspect ratio of the β-chitin decreased as a result of the exscessive disintegration. The storage moduli of the ChNFs were greater than those of chitin solutions, nanorods, and nanowhiskers with the same solids concentrations. Copyright © 2018 Elsevier B.V. All rights reserved.

Homogeneous synthesis of quaternized chitin in NaOH/urea aqueous solution as a potential gene vector.

PubMed

Peng, Na; Ai, Ziye; Fang, Zehong; Wang, Yanfeng; Xia, Zhiping; Zhong, Zibiao; Fan, Xiaoli; Ye, Qifa

2016-10-05

Water-soluble quaternized chitins (QCs) were homogeneously synthesized by reacting chitin with (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC) in 8wt% NaOH/4wt% urea aqueous solutions. The chemical structure and solution properties of the quaternized chitins were characterized by (1)H NMR, FT-IR, elemental analysis, dynamic light scattering (DLS) and zeta potential measurements. The results demonstrated that the water-soluble QCs, with a degree of substitution (DS) values of 0.27-0.54, could be obtained by varying the concentration of chitin, the molar ratio of CHPTAC to chitin unit, and the reaction time at room temperature (25°C). Two QCs (DS=0.36 and 0.54) were selected and studied as gene carriers. Agarose gel retardation assay revealed that both QCs could condense DNA efficiently when N/P ratio>3. The results of particle size and zeta potential indicated that both QCs had a good ability of condensing plasmid DNA into compact nanoparticles with the size of 100-200nm and zeta potential of +18 to +36mV. Compared to polyethylenimine (PEI, 25kDa), the QCs exhibited outstanding low cytotoxicity. Transfection efficiencies of the QCs/DNA complexes were measured using pGL-3 encoding luciferase as the foreign DNA, and the QCs/DNA complexes showed effective transfection efficiencies in 293T cells. These results revealed that the QCs prepared in NaOH/urea aqueous solutions could be used as promising non-viral gene carriers owing to their excellent characteristics. Copyright © 2016. Published by Elsevier Ltd.

Lysin Motif–Containing Proteins LYP4 and LYP6 Play Dual Roles in Peptidoglycan and Chitin Perception in Rice Innate Immunity[W][OA

PubMed Central

Liu, Bing; Li, Jian-Feng; Ao, Ying; Qu, Jinwang; Li, Zhangqun; Su, Jianbin; Zhang, Yang; Liu, Jun; Feng, Dongru; Qi, Kangbiao; He, Yanming; Wang, Jinfa; Wang, Hong-Bin

2012-01-01

Plant innate immunity relies on successful detection of microbe-associated molecular patterns (MAMPs) of invading microbes via pattern recognition receptors (PRRs) at the plant cell surface. Here, we report two homologous rice (Oryza sativa) lysin motif–containing proteins, LYP4 and LYP6, as dual functional PRRs sensing bacterial peptidoglycan (PGN) and fungal chitin. Live cell imaging and microsomal fractionation consistently revealed the plasma membrane localization of these proteins in rice cells. Transcription of these two genes could be induced rapidly upon exposure to bacterial pathogens or diverse MAMPs. Both proteins selectively bound PGN and chitin but not lipopolysaccharide (LPS) in vitro. Accordingly, silencing of either LYP specifically impaired PGN- or chitin- but not LPS-induced defense responses in rice, including reactive oxygen species generation, defense gene activation, and callose deposition, leading to compromised resistance against bacterial pathogen Xanthomonas oryzae and fungal pathogen Magnaporthe oryzae. Interestingly, pretreatment with excess PGN dramatically attenuated the alkalinization response of rice cells to chitin but not to flagellin; vice versa, pretreatment with chitin attenuated the response to PGN, suggesting that PGN and chitin engage overlapping perception components in rice. Collectively, our data support the notion that LYP4 and LYP6 are promiscuous PRRs for PGN and chitin in rice innate immunity. PMID:22872757

CHITIN TRANSFORMATION AND PESTICIDE INTERACTIONS IN A SIMULATED AQUATIC MICROENVIRONMENTAL SYSTEM

EPA Science Inventory

Interactions between the structural animo-polysaccharide, chitin, and the organophosphate pesticide, azinphosmethyl (Guthion), have been studied in a controlled continuous flow-through microcosm. Pesticide-induced microbial population changes and increases in substrate utilizatio...

Two homologous genes, DCW1 (YKL046c) and DFG5, are essential for cell growth and encode glycosylphosphatidylinositol (GPI)-anchored membrane proteins required for cell wall biogenesis in Saccharomyces cerevisiae.

PubMed

Kitagaki, Hiroshi; Wu, Hong; Shimoi, Hitoshi; Ito, Kiyoshi

2002-11-01

The cell wall of Saccharomyces cerevisiae consists of glucan, chitin and various kinds of mannoproteins. Major parts of mannoproteins are synthesized as glycosylphosphatidylinositol (GPI)-anchored proteins and are then transferred to cell wall beta-1,6-glucan. A glycosyltransferase has been hypothesized to catalyse this transfer reaction. A database search revealed that the products of YKL046c and DFG5 are homologous to bacterial mannosidase. These genes are homologous to each other and have primary structures characteristic of GPI-anchored proteins. Although single disruptants of ykl046c and dfg5 were viable, ykl046cDelta was hypersensitive to a cell wall-digesting enzyme (zymolyase), suggesting that this gene is involved in cell wall biosynthesis. We therefore designated this gene as DCW1 (defective cell wall). A double disruptant of dcw1 and dfg5 was synthetically lethal, indicating that the functions of these gene products are redundant, and at least one of them is required for cell growth. Cells deficient in both Dcw1p and Dfg5p were round and large, had cell walls that contained an increased amount of chitin and secreted a major cell wall protein, Cwp1p, into the medium. Biochemical analyses showed that epitope-tagged Dcw1p is an N-glycosylated, GPI-anchored membrane protein and is localized in the membrane fraction including the cell surface. These results suggest that both Dcw1p and Dfg5p are GPI-anchored membrane proteins and are required for normal biosynthesis of the cell wall.

Concurrent protein synthesis is required for in vivo chitin synthesis in postmolt blue crabs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horst, M.N.

1990-12-01

Chitin synthesis in crustaceans involves the deposition of a protein-polysaccharide complex at the apical surface of epithelial cells which secrete the cuticle or exoskeleton. The present study involves an examination of in vivo incorporation of radiolabeled amino acids and amino sugars into the cuticle of postmolt blue crabs, Callinectes sapidus. Rates of incorporation of both 3H leucine and 3H threonine were linear with respect to time of incubation. Incorporation of 3H threonine into the endocuticle was inhibited greater than 90% in the presence of the protein synthesis inhibitor, puromycin. Linear incorporation of 14C glucosamine into the cuticle was also demonstrated;more » a significant improvement of radiolabeling was achieved by using 14C-N-acetylglucosamine as the labeled precursor. Incorporation of 3H-N-acetylglucosamine into the cuticle of postmolt blue crabs was inhibited 89% by puromycin, indicating that concurrent protein synthesis is required for the deposition of chitin in the blue crab. Autoradiographic analysis of control vs. puromycin-treated crabs indicates that puromycin totally blocks labeling of the new endocuticle with 3H glucosamine. These results are consistent with the notion that crustacean chitin is synthesized as a protein-polysaccharide complex. Analysis of the postmolt and intermolt blue crab cuticle indicates that the exoskeleton contains about 60% protein and 40% chitin. The predominant amino acids are arginine, glutamic acid, alanine, aspartic acid, and threonine.« less

Kinetics of de-N-acetylation of the chitin disaccharide in aqueous sodium hydroxide solution.

PubMed

Khong, Thang Trung; Aachmann, Finn L; Vårum, Kjell M

2012-05-01

Chitosan is prepared from chitin, a process which is carried out at highly alkaline conditions, and that can be performed either on chitin in solution (homogeneous deacetylation) or heterogeneously with the chitin as a solid throughout the reaction. We report here a study of the de-N-acetylation reaction of the chitin dimer (GlcNAc-GlcNAc) in solution. The reaction was followed by (1)H NMR spectroscopy in deuterated aqueous sodium hydroxide solution as a function of time, sodium-hydroxide concentration and temperature. The (1)H NMR spectrum of GlcNAc-GlcNAc in 2.77 M deuterated aqueous sodium hydroxide solution was assigned. The interpretation of the (1)H NMR spectra allowed us to determine the rates of de-N-acetylation of the reducing and non-reducing ends, showing that the reaction rate at the reducing end is twice the rate at the non-reducing end. The total deacetylation reaction rate was determined as a function of the hydroxide ion concentration, showing for the first time that this de-N-acetylation reaction is second order with respect to hydroxide ion concentration. No significant difference in the deacetylation rates in deuterated water compared to water was observed. The activation energy for the reaction (26-54 °C) was determined to 114.4 and 98.6 kJ/mol at 2.77 and 5.5 M in deuterated aqueous sodium hydroxide solution, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Cell wall staining with Trypan blue enables quantitative analysis of morphological changes in yeast cells.

PubMed

Liesche, Johannes; Marek, Magdalena; Günther-Pomorski, Thomas

2015-01-01

Yeast cells are protected by a cell wall that plays an important role in the exchange of substances with the environment. The cell wall structure is dynamic and can adapt to different physiological states or environmental conditions. For the investigation of morphological changes, selective staining with fluorescent dyes is a valuable tool. Furthermore, cell wall staining is used to facilitate sub-cellular localization experiments with fluorescently-labeled proteins and the detection of yeast cells in non-fungal host tissues. Here, we report staining of Saccharomyces cerevisiae cell wall with Trypan Blue, which emits strong red fluorescence upon binding to chitin and yeast glucan; thereby, it facilitates cell wall analysis by confocal and super-resolution microscopy. The staining pattern of Trypan Blue was similar to that of the widely used UV-excitable, blue fluorescent cell wall stain Calcofluor White. Trypan Blue staining facilitated quantification of cell size and cell wall volume when utilizing the optical sectioning capacity of a confocal microscope. This enabled the quantification of morphological changes during growth under anaerobic conditions and in the presence of chemicals, demonstrating the potential of this approach for morphological investigations or screening assays.

Cell walls of the dimorphic fungal pathogens Sporothrix schenckii and Sporothrix brasiliensis exhibit bilaminate structures and sloughing of extensive and intact layers

PubMed Central

Walker, Louise A.; Niño-Vega, Gustavo; Mora-Montes, Héctor M.; Neves, Gabriela W. P.; Villalobos-Duno, Hector; Barreto, Laura; Garcia, Karina; Franco, Bernardo; Martínez-Álvarez, José A.; Munro, Carol A.; Gow, Neil A. R.

2018-01-01

Sporotrichosis is a subcutaneous mycosis caused by pathogenic species of the Sporothrix genus. A new emerging species, Sporothrix brasiliensis, is related to cat-transmitted sporotrichosis and has severe clinical manifestations. The cell wall of pathogenic fungi is a unique structure and impacts directly on the host immune response. We reveal and compare the cell wall structures of Sporothrix schenckii and S. brasiliensis using high-pressure freezing electron microscopy to study the cell wall organization of both species. To analyze the components of the cell wall, we also used infrared and 13C and 1H NMR spectroscopy and the sugar composition was determined by quantitative high-performance anion-exchange chromatography. Our ultrastructural data revealed a bi-layered cell wall structure for both species, including an external microfibrillar layer and an inner electron-dense layer. The inner and outer layers of the S. brasiliensis cell wall were thicker than those of S. schenckii, correlating with an increase in the chitin and rhamnose contents. Moreover, the outer microfibrillar layer of the S. brasiliensis cell wall had longer microfibrils interconnecting yeast cells. Distinct from those of other dimorphic fungi, the cell wall of Sporothrix spp. lacked α-glucan component. Interestingly, glycogen α-particles were identified in the cytoplasm close to the cell wall and the plasma membrane. The cell wall structure as well as the presence of glycogen α-particles varied over time during cell culture. The structural differences observed in the cell wall of these Sporothrix species seemed to impact its uptake by monocyte-derived human macrophages. The data presented here show a unique cell wall structure of S. brasiliensis and S. schenckii during the yeast parasitic phase. A new cell wall model for Sporothrix spp. is therefore proposed that suggests that these fungi molt sheets of intact cell wall layers. This observation may have significant effects on localized and

Micro-CT Imaging of Denatured Chitin by Silver to Explore Honey Bee and Insect Pathologies

PubMed Central

Butzloff, Peter R.

2011-01-01

Background Chitin and cuticle coatings are important to the environmental and immune defense of honey bees and insect pollinators. Pesticides or environmental effects may target the biochemistry of insect chitin and cuticle coating. Denaturing of chitin involves a combination of deacetylation, intercalation, oxidation, Schweiger-peeling, and the formation of amine hydrochloride salt. The term “denatured chitin” calls attention to structural and property changes to the internal membranes and external carapace of organisms so that some properties affecting biological activities are diminished. Methodology/Principal Findings A case study was performed on honey bees using silver staining and microscopic computer-tomographic x-ray radiography (micro-CT). Silver nitrate formed counter-ion complexes with labile ammonium cations and reacted with amine hydrochloride. Silver was concentrated in the peritrophic membrane, on the abdomen, in the glossa, at intersegmental joints (tarsi), at wing attachments, and in tracheal air sacs. Imaged mono-esters and fatty acids from cuticle coating on external surfaces were apparently reduced by an alcohol pretreatment. Conclusions/Significance The technique provides 3-dimensional and sectional images of individual honey bees consistent with the chemistries of silver reaction and complex formation with denatured chitin. Environmental exposures and influences such as gaseous nitric oxide intercalant, trace oxidants such as ozone gas, oligosachharide salt conversion, exposure to acid rain, and chemical or biochemical denaturing by pesticides may be studied using this technique. Peritrophic membranes, which protect against food abrasion, microorganisms, and permit efficient digestion, were imaged. Apparent surface damage to the corneal lenses of compound eyes by dilute acid exposure consistent with chitin amine hydrochloride formation was imaged. The technique can contribute to existing insect pathology research, and may provide an

Colloidal chitin nanogels: A plethora of applications under one shell.

PubMed

Vishnu Priya, M; Sabitha, M; Jayakumar, R

2016-01-20

Chitin nanogels (CNGs) are a relatively new class of natural polymeric nanomaterials which have a large potential in the field of drug delivery and nanotherapeutics. These nanogels being very biocompatible are non-toxic when internalized by cells. In this review various properties, preparation techniques and applications of CNGs have been described. CNGs because of their nano-size possess certain unique properties which enable them to be used in a number of biomedical applications. CNGs are prepared by simple regeneration technique without using any cross-linkers. Various polymers, drugs and fluorescent dyes can be blended or incorporated or labelled with the chitin hydrogel network. Drugs and molecules encapsulated within CNGs can be used for targeted delivery, in vivo monitoring or even for therapeutic purposes. Here various applications of CNGs in the field of drug delivery, imaging, sensing and therapeutics have been discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Overexpression of a BAHD Acyltransferase, OsAt10, Alters Rice Cell Wall Hydroxycinnamic Acid Content and Saccharification1[C][W][OA

PubMed Central

Bartley, Laura E.; Peck, Matthew L.; Kim, Sung-Ryul; Ebert, Berit; Manisseri, Chithra; Chiniquy, Dawn M.; Sykes, Robert; Gao, Lingfang; Rautengarten, Carsten; Vega-Sánchez, Miguel E.; Benke, Peter I.; Canlas, Patrick E.; Cao, Peijian; Brewer, Susan; Lin, Fan; Smith, Whitney L.; Zhang, Xiaohan; Keasling, Jay D.; Jentoff, Rolf E.; Foster, Steven B.; Zhou, Jizhong; Ziebell, Angela; An, Gynheung; Scheller, Henrik V.; Ronald, Pamela C.

2013-01-01

Grass cell wall properties influence food, feed, and biofuel feedstock usage efficiency. The glucuronoarabinoxylan of grass cell walls is esterified with the phenylpropanoid-derived hydroxycinnamic acids ferulic acid (FA) and para-coumaric acid (p-CA). Feruloyl esters undergo oxidative coupling with neighboring phenylpropanoids on glucuronoarabinoxylan and lignin. Examination of rice (Oryza sativa) mutants in a grass-expanded and -diverged clade of BAHD acyl-coenzyme A-utilizing transferases identified four mutants with altered cell wall FA or p-CA contents. Here, we report on the effects of overexpressing one of these genes, OsAt10 (LOC_Os06g39390), in rice. An activation-tagged line, OsAT10-D1, shows a 60% reduction in matrix polysaccharide-bound FA and an approximately 300% increase in p-CA in young leaf tissue but no discernible phenotypic alterations in vegetative development, lignin content, or lignin composition. Two additional independent OsAt10 overexpression lines show similar changes in FA and p-CA content. Cell wall fractionation and liquid chromatography-mass spectrometry experiments isolate the cell wall alterations in the mutant to ester conjugates of a five-carbon sugar with p-CA and FA. These results suggest that OsAT10 is a p-coumaroyl coenzyme A transferase involved in glucuronoarabinoxylan modification. Biomass from OsAT10-D1 exhibits a 20% to 40% increase in saccharification yield depending on the assay. Thus, OsAt10 is an attractive target for improving grass cell wall quality for fuel and animal feed. PMID:23391577

Towards the Shell Biorefinery: Sustainable Synthesis of the Anticancer Alkaloid Proximicin A from Chitin.

PubMed

Sadiq, Alejandro D; Chen, Xi; Yan, Ning; Sperry, Jonathan

2018-02-09

A shell biorefinery would involve fractionation of crustacean shells and incorporation of the components into value-added products, particularly those that contain nitrogen. In a proof-of-concept study that validates this concept, the anticancer alkaloid proximicin A has been synthesized from the chitin-derived platform chemical 3-acetamido-5-acetylfuran (3A5AF). This study accentuates the leading role chitin is likely to play in the sustainable production of nitrogen-containing fine chemicals that are not directly attainable from lignocellulose. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exploiting fungal cell wall components in vaccines.

PubMed

Levitz, Stuart M; Huang, Haibin; Ostroff, Gary R; Specht, Charles A

2015-03-01

Innate recognition of fungi leads to strong adaptive immunity. Investigators are trying to exploit this observation in vaccine development by combining antigens with evolutionarily conserved fungal cell wall carbohydrates to induce protective responses. Best studied is β-1,3-glucan, a glycan that activates complement and is recognized by dectin-1. Administration of antigens in association with β-1,3-glucan, either by direct conjugation or complexed in glucan particles, results in robust humoral and cellular immune responses. While the host has a host of mannose receptors, responses to fungal mannoproteins generally are amplified if cells are cooperatively stimulated with an additional danger signal such as a toll-like receptor agonist. Chitosan, a polycationic homopolymer of glucosamine manufactured by the deacetylation of chitin, is being studied as an adjuvant in DNA and protein-based vaccines. It appears particularly promising in mucosal vaccines. Finally, universal and organism-specific fungal vaccines have been formulated by conjugating fungal cell wall glycans to carrier proteins. A major challenge will be to advance these experimental findings so that at risk patients can be protected.

Exploiting fungal cell wall components in vaccines

PubMed Central

Levitz, Stuart M.; Huang, Haibin; Ostroff, Gary R.; Specht, Charles A.

2014-01-01

Innate recognition of fungi leads to strong adaptive immunity. Investigators are trying to exploit this observation in vaccine development by combining antigens with evolutionarily conserved fungal cell wall carbohydrates to induce protective responses. Best studied is β-1,3-glucan, a glycan that activates complement and is recognized by Dectin-1. Administration of antigens in association with β-1,3-glucan, either by direct conjugation or complexed in glucan particles, results in robust humoral and cellular immune responses. While the host has a host of mannose receptors, responses to fungal mannoproteins generally are amplified if cells are cooperatively stimulated with an additional danger signal such as a toll-like receptor agonist. Chitosan, a polycationic homopolymer of glucosamine manufactured by the deacetylation of chitin, is being studied as an adjuvant in DNA and protein-based vaccines. It appears particularly promising in mucosal vaccines. Finally, universal and organism-specific fungal vaccines have been formulated by conjugating fungal cell wall glycans to carrier proteins. A major challenge will be to advance these experimental findings so that at risk patients can be protected. PMID:25404118

Regulatory functions of trehalose-6-phosphate synthase in the chitin biosynthesis pathway in Tribolium castaneum (Coleoptera: Tenebrionidae) revealed by RNA interference.

PubMed

Chen, Q W; Jin, S; Zhang, L; Shen, Q D; Wei, P; Wei, Z M; Wang, S G; Tang, B

2018-06-01

RNA interference (RNAi) is a very effective technique for studying gene function and may be an efficient method for controlling pests. Trehalose-6-phosphate synthase (TPS), which plays a key role in the synthesis of trehalose and insect development, was cloned in Tribolium castaneum (Herbst) (TcTPS) and the putative functions were studied using RNAi via the injection of double-stranded RNA (dsRNA) corresponding to conserved TPS and trehalose-6-phosphate phosphatase domains. Expression analyses show that TcTPS is expressed higher in the fat body, while quantitative real-time polymerase chain reaction results show that the expression of four trehalase isoforms was significantly suppressed by dsTPS injection. Additionally, the expression of six chitin synthesis-related genes, such as hexokinase 2 and glutamine-fructose-6-phosphate aminotransferase, was suppressed at 48 and 72 h post-dsTPS-1 and dsTPS-2 RNA injection, which were two dsTPS fragments that had been designed for two different locations in TcTPS open reading frame, and that trehalose content and trehalase 1 activity decreased significantly at 72 h post-dsRNA injection. Furthermore, T. castaneum injected with dsTPS-1 and dsTPS-2 RNA displayed significantly lower levels of chitin and could not complete the molting process from larvae to pupae, revealing abnormal molting phenotypes. These results demonstrate that silencing TPS gene leads to molting deformities and high mortality rates via regulation of gene expression in the chitin biosynthetic pathway, and may be a promising approach for pest control in the future.

Co-Processed Chitin-Mannitol as a New Excipient for Oro-Dispersible Tablets

PubMed Central

Daraghmeh, Nidal; Chowdhry, Babur Z.; Leharne, Stephen A.; Al Omari, Mahmoud M. H.; Badwan, Adnan A.

2015-01-01

This study describes the preparation, characterization and performance of a novel excipient for use in oro-dispersible tablets (ODT). The excipient (Cop–CM) consists of chitin and mannitol. The excipient with optimal physicochemical properties was obtained at a chitin: mannitol ratio of 2:8 (w/w) and produced by roll compaction (RC). Differential scanning calorimetry (DSC), Fourier transform-Infrared (FT-IR), X-ray powder diffraction (XRPD) and scanning electron microscope (SEM) techniques were used to characterize Cop–CM, in addition to characterization of its powder and ODT dosage form. The effect of particle size distribution of Cop–CM was investigated and found to have no significant influence on the overall tablet physical properties. The compressibility parameter (a) for Cop–CM was calculated from a Kawakita plot and found to be higher (0.661) than that of mannitol (0.576) due to the presence of the highly compressible chitin (0.818). Montelukast sodium and domperidone ODTs produced, using Cop–CM, displayed excellent physicochemical properties. The exceptional binding, fast wetting and superdisintegration properties of Cop–CM, in comparison with commercially available co-processed ODT excipients, results in a unique multifunctional base which can successfully be used in the formulation of oro-dispersible and fast immediate release tablets. PMID:25830680

Genome-wide identification of chitinase and chitin deacetylase gene families in the oriental fruit fly, Bactrocera dorsalis (Hendel).

PubMed

Liu, Shi-Huo; Li, Hong-Fei; Yang, Yang; Yang, Rui-Lin; Yang, Wen-Jia; Jiang, Hong-Bo; Dou, Wei; Smagghe, Guy; Wang, Jin-Jun

2018-05-01

Chitinases (Chts) and chitin deacetylases (CDAs) are important enzymes required for chitin metabolism in insects. In this study, 12 Cht-related genes (including seven Cht genes and five imaginal disc growth factor genes) and 6 CDA genes (encoding seven proteins) were identified in Bactrocera dorsalis using genome-wide searching and transcript profiling. Based on the conserved sequences and phylogenetic relationships, 12 Cht-related proteins were clustered into eight groups (group I-V and VII-IX). Further domain architecture analysis showed that all contained at least one chitinase catalytic domain, however, only four (BdCht5, BdCht7, BdCht8 and BdCht10) possessed chitin-binding domains. The subsequent phylogenetic analysis revealed that seven CDAs were clustered into five groups (group I-V), and all had one chitin deacetylase catalytic domain. However, only six exhibited chitin-binding domains. Finally, the development- and tissue-specific expression profiling showed that transcript levels of the 12 Cht-related genes and 6 CDA genes varied considerably among eggs, larvae, pupae and adults, as well as among different tissues of larvae and adults. Our findings illustrate the structural differences and expression patterns of Cht and CDA genes in B. dorsalis, and provide important information for the development of new pest control strategies based on these vital enzymes. Copyright © 2018. Published by Elsevier Inc.

Cell wall formation in zoospores of Allomyces arbuscula. II. Development of surface structure of encysted haploid zoospores, rhizoids, and hyphae.

PubMed

Kroh, M; Hendriks, H; Kirby, E G; Sassen, M M

1976-08-01

Development of haploid meiospores of Allomyces arbuscula into germling cells with rhizoids and hyphae was followed during incubation in complete growth medium. The surface structure of encysted meiospores, rhizoids and hyphae before and after extraction of amorphous materials with ethanolic KOH was studied by means of carbon-platinum replicas. After 2--3 min incubation in complete medium 10% of the meiospores were surrounded by a cell wall containing microfibrils embedded in a matrix. Structure of cell walls of encysted meiospores, rhizoids, and hyphae differ from one another by the location of amorphous materials and by the arrangement of chitin microfibrils.

Role of the C-terminal and chitin insertion domains on enzymatic activity of endochitinase ChiA74 of Bacillus thuringiensis.

PubMed

Juárez-Hernández, Estefania O; Casados-Vázquez, Luz E; Bideshi, Dennis K; Salcedo-Hernández, R; Barboza-Corona, José E

2017-09-01

ChiA74 has modular structure that includes a secretion signal peptide (sp) sequence, and catalytic (CD), chitin insertion (CID), fibronectin type-III (FnIII) and chitin binding (CBD) domains. We described for the first time the existence of a putative CID in ChiA74. Mature ChiA74 lacking its sp sequence (rChiA74Δsp, ∼70kDa) and two truncated versions, rChiA74Δsp-60, rChiA74Δsp-50 lacking, respectively, CBD and CDB-FnIII were produced. rChiA74Δsp and rChiA74Δsp-60 are unstable and were processed to generate stable proteins of ∼50kDa. With colloidal chitin, rChiA74Δsp and rChiA74Δsp-50 had higher activity than rChiA74Δsp-60. rChiA74Δsp showed similar ability to bind chitin than rChiA74Δsp-50. The catalytic efficiencies (kcat/Km) of rChiA74Δsp and rChiA74Δsp-50 were higher, ∼ 21-fold than rChiA74Δsp-60, using chitin as the substrate. Optimal activity was detected at pH 7 and 40°C. Data suggest that the CBD in ChiA74 is important for binding to chitin, but not necessary as the presence of a CID together with the CD in a stable truncated version (i.e. ChiA74Δsp-50) has similar affinity and hydrolytic activity as the mature enzyme. The CID of ChiA74 showed identities of ∼ 55% with CIDs of other chitinases such as those from B. circulans and B. licheniformis, respectively, and conserved residues important for interacting with chitin. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of Chitin Isolated from Crustaceans and Cephalopods on Denaturation of Fish Myofibrillar Protein and the State of Water during Frozen Storage

NASA Astrophysics Data System (ADS)

Arredondo Romero, Eduardo; Nakamura, Yukio; Yamashita, Yasumitsu; Ichikawa, Hisashi; Goto, Shingi; Osatomi, Kiyoshi; Nozaki, Yukinori

From the point of view of utilization of shells as a waste product of fishery industry, the cryoprotective effect of chitin made from shell of crustaceans (Japanese fan lobster and Japanese swimming crab) and cartilage of cephalopods (spear squid) are studied. Chitin from the shells and cartilage were added to lizard fish myofibrils, and the changes of unfrozen water in myofibrils and ATPase activity of myofibrillar protein were observed during frozen storage at -250°C for 120days. The amount of unfrozen water were increased by addition of three kinds of chitin, and decreased moderately during forzen storage. Whereas, in the chitin free sample, the amount of unfrozen water were decreased rapidly during frozen storage. Changes of ATPase activity of samples showed similar tendency to that of the amount of unfrozen water. The present moderate cryoprotective effect of chitin and data of unfrozen water and ATPase activity of myofibrillar protein suggest the importance of the amount of unfrozen water in frozen matrix.

Identification of the Mamestra configurata (Lepidoptera: Noctuidae) peritrophic matrix proteins and enzymes involved in peritrophic matrix chitin metabolism.

PubMed

Toprak, Umut; Erlandson, Martin; Baldwin, Doug; Karcz, Steve; Wan, Lianglu; Coutu, Cathy; Gillott, Cedric; Hegedus, Dwayne D

2016-10-01

The peritrophic matrix (PM) is essential for insect digestive system physiology as it protects the midgut epithelium from damage by food particles, pathogens, and toxins. The PM is also an attractive target for development of new pest control strategies due to its per os accessibility. To understand how the PM performs these functions, the molecular architecture of the PM was examined using genomic and proteomic approaches in Mamestra configurata (Lepidoptera: Noctuidae), a major pest of cruciferous oilseed crops in North America. Liquid chromatography-tandem mass spectrometry analyses of the PM identified 82 proteins classified as: (i) peritrophins, including a new class with a CBDIII domain; (ii) enzymes involved in chitin modification (chitin deacetylases), digestion (serine proteases, aminopeptidases, carboxypeptidases, lipases and α-amylase) or other reactions (β-1,3-glucanase, alkaline phosphatase, dsRNase, astacin, pantetheinase); (iii) a heterogenous group consisting of polycalin, REPATs, serpin, C-Type lectin and Lsti99/Lsti201 and 3 novel proteins without known orthologs. The genes encoding PM proteins were expressed predominantly in the midgut. cDNAs encoding chitin synthase-2 (McCHS-2), chitinase (McCHI), and β-N-acetylglucosaminidase (McNAG) enzymes, involved in PM chitin metabolism, were also identified. McCHS-2 expression was specific to the midgut indicating that it is responsible for chitin synthesis in the PM, the only chitinous material in the midgut. In contrast, the genes encoding the chitinolytic enzymes were expressed in multiple tissues. McCHS-2, McCHI, and McNAG were expressed in the midgut of feeding larvae, and NAG activity was present in the PM. This information was used to generate an updated model of the lepidopteran PM architecture. © 2015 Institute of Zoology, Chinese Academy of Sciences.

Facile Fabrication of Nanofibrillated Chitin/Ag2O Heterostructured Aerogels with High Iodine Capture Efficiency.

PubMed

Gao, Runan; Lu, Yun; Xiao, Shaoliang; Li, Jian

2017-06-27

Nanofibrillated chitin/Ag 2 O aerogels were fabricated for radioiodine removal. Chitin was first fabricated into nanofibers with abundant acetyl amino groups (-NHCOCH 3 ) on the surface. Then, highly porous chitin nanofiber (ChNF) aerogels were obtained via freeze-drying. The ChNF aerogels exhibited a low bulk density of 2.19 mg/cm 3 and a high specific surface area of 179.71 m 2 /g. Ag 2 O nanoparticles were evenly anchored on the surfaces of ChNF scaffolds via strong interactions with -NHCOCH 3 groups, subsequently yielding Ag 2 O@ChNF heterostructured aerogels. The composites were used as efficient absorbents to remove radioiodine anions from water and capture a high amount of I 2 vapor in the forms of AgI and iodine molecules. The adsorption capacity of the composite monoliths can reach up to 2.81 mmol/g of I - anions. The high adsorbability of the composite monolithic aerogel signifies its potential applications in radioactive waste disposal.

A shared mechanism of defense against predators and parasites: chitin regulation and its implications for life-history theory.

PubMed

Beckerman, Andrew P; de Roij, Job; Dennis, Stuart R; Little, Tom J

2013-12-01

Defenses against predators and parasites offer excellent illustrations of adaptive phenotypic plasticity. Despite vast knowledge about such induced defenses, they have been studied largely in isolation, which is surprising, given that predation and parasitism are ubiquitous and act simultaneously in the wild. This raises the possibility that victims must trade-off responses to predation versus parasitism. Here, we propose that arthropod responses to predators and parasites will commonly be based on the endocrine regulation of chitin synthesis and degradation. The proposal is compelling because many inducible defenses are centered on temporal or spatial modifications of chitin-rich structures. Moreover, we show how the chitin synthesis pathway ends in a split to carapace or gut chitin, and how this form of molecular regulation can be incorporated into theory on life-history trade-offs, specifically the Y-model. Our hypothesis thus spans several biological scales to address advice from Stearns that "Endocrine mechanisms may prove to be only the tip of an iceberg of physiological mechanisms that modulate the expression of genetic covariance".

Resistance mutation conserved between insects and mites unravels the benzoylurea insecticide mode of action on chitin biosynthesis.

PubMed

Douris, Vassilis; Steinbach, Denise; Panteleri, Rafaela; Livadaras, Ioannis; Pickett, John Anthony; Van Leeuwen, Thomas; Nauen, Ralf; Vontas, John

2016-12-20

Despite the major role of chitin biosynthesis inhibitors such as benzoylureas (BPUs) in the control of pests in agricultural and public health for almost four decades, their molecular mode of action (MoA) has in most cases remained elusive. BPUs interfere with chitin biosynthesis and were thought to interact with sulfonylurea receptors that mediate chitin vesicle transport. Here, we uncover a mutation (I1042M) in the chitin synthase 1 (CHS1) gene of BPU-resistant Plutella xylostella at the same position as the I1017F mutation reported in spider mites that confers etoxazole resistance. Using a genome-editing CRISPR/Cas9 approach coupled with homology-directed repair (HDR) in Drosophila melanogaster, we introduced both substitutions (I1056M/F) in the corresponding fly CHS1 gene (kkv). Homozygous lines bearing either of these mutations were highly resistant to etoxazole and all tested BPUs, as well as buprofezin-an important hemipteran chitin biosynthesis inhibitor. This provides compelling evidence that BPUs, etoxazole, and buprofezin share in fact the same molecular MoA and directly interact with CHS. This finding has immediate effects on resistance management strategies of major agricultural pests but also on mosquito vectors of serious human diseases such as Dengue and Zika, as diflubenzuron, the standard BPU, is one of the few effective larvicides in use. The study elaborates on how genome editing can directly, rapidly, and convincingly elucidate the MoA of bioactive molecules, especially when target sites are complex and hard to reconstitute in vitro.

Resistance mutation conserved between insects and mites unravels the benzoylurea insecticide mode of action on chitin biosynthesis

PubMed Central

Steinbach, Denise; Panteleri, Rafaela; Livadaras, Ioannis; Van Leeuwen, Thomas; Nauen, Ralf; Vontas, John

2016-01-01

Despite the major role of chitin biosynthesis inhibitors such as benzoylureas (BPUs) in the control of pests in agricultural and public health for almost four decades, their molecular mode of action (MoA) has in most cases remained elusive. BPUs interfere with chitin biosynthesis and were thought to interact with sulfonylurea receptors that mediate chitin vesicle transport. Here, we uncover a mutation (I1042M) in the chitin synthase 1 (CHS1) gene of BPU-resistant Plutella xylostella at the same position as the I1017F mutation reported in spider mites that confers etoxazole resistance. Using a genome-editing CRISPR/Cas9 approach coupled with homology-directed repair (HDR) in Drosophila melanogaster, we introduced both substitutions (I1056M/F) in the corresponding fly CHS1 gene (kkv). Homozygous lines bearing either of these mutations were highly resistant to etoxazole and all tested BPUs, as well as buprofezin—an important hemipteran chitin biosynthesis inhibitor. This provides compelling evidence that BPUs, etoxazole, and buprofezin share in fact the same molecular MoA and directly interact with CHS. This finding has immediate effects on resistance management strategies of major agricultural pests but also on mosquito vectors of serious human diseases such as Dengue and Zika, as diflubenzuron, the standard BPU, is one of the few effective larvicides in use. The study elaborates on how genome editing can directly, rapidly, and convincingly elucidate the MoA of bioactive molecules, especially when target sites are complex and hard to reconstitute in vitro. PMID:27930336

Formation of Helically Structured Chitin/CaCO3 Hybrids through an Approach Inspired by the Biomineralization Processes of Crustacean Cuticles.

PubMed

Matsumura, Shunichi; Kajiyama, Satoshi; Nishimura, Tatsuya; Kato, Takashi

2015-10-01

Chitin/CaCO3 hybrids with helical structures are formed through a biomineralization-inspired crystallization process under ambient conditions. Liquid-crystalline chitin whiskers are used as helically ordered templates. The liquid-crystalline structures are stabilized by acidic polymer networks which interact with the chitin templates. The crystallization of CaCO3 is conducted by soaking the templates in the colloidal suspension of amorphous CaCO3 (ACC) at room temperature. At the initial stage of crystallization, ACC particles are introduced inside the templates, and they crystallize to CaCO3 nanocrystals. The acidic polymer networks induce CaCO3 crystallization. The characterization of the resultant hybrids reveals that they possess helical order and homogeneous hybrid structures of chitin and CaCO3 , which resemble the structure and composition of the exoskeleton of crustaceans. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Genes Associated with Food Allergy and Eosinophilic Esophagitis

DTIC Science & Technology

2013-11-01

conserved enzymes present not only in lower life forms but also inmammals that can cleave chitin a nat- urally occurring polysaccharide composed of N...acetylglucosamine re- peats [1,2]. Chitin is highly expressed in insects and crustacean exoskeletons, fungal cell walls, and microfilarial nematode...sheaths [3]. Levels of chitin are regulated by enzymes synthesizing chitin (i.e. chitin synthase) or degrading chitin (i.e. chitinases). Although

The preparation and characterization of chitin and chitosan under large-scale submerged fermentation level using shrimp by-products as substrate.

PubMed

Zhang, Hongcai; Yun, Sanyue; Song, Lingling; Zhang, Yiwen; Zhao, Yanyun

2017-03-01

The crustacean shells of crabs and shrimps produces quantities of by-products, leading to seriously environmental pollution and human health problems during industrial processing, yet they turned into high-value useful products, such as chitin and chitosan. To prepare them under large-scale submerged fermentation level, shrimp shell powders (SSPs) was fermented by successive three-step fermentation of Serratia marcescens B742, Lactobacillus plantarum ATCC 8014 and Rhizopus japonicus M193 to extract chitin and chitosan based on previously optimal conditions. Moreover, the key parameters was investigated to monitor the changes of resulted products during fermentation process. The results showed that the yield of prepared chitin and chitosan reached 21.35 and 13.11% with the recovery rate of 74.67 and 63.42%, respectively. The degree of deacetylation (DDA) and molecular mass (MM) of produced chitosan were 81.23% and 512.06kDa, respectively. The obtained chitin and chitosan was characterized using Fourier transform infrared spectrometer (FT-IR) and X-ray diffraction (XRD) analysis. The established microbial fermentation method can be applied for the industrial large-scale production of chitin and chitosan, while the use of chemical reagents was significantly reduced. Copyright © 2016 Elsevier B.V. All rights reserved.

Cell Wall and Secreted Proteins of Candida albicans: Identification, Function, and Expression

PubMed Central

Chaffin, W. Lajean; López-Ribot, José Luis; Casanova, Manuel; Gozalbo, Daniel; Martínez, José P.

1998-01-01

The cell wall is essential to nearly every aspect of the biology and pathogenicity of Candida albicans. Although it was intially considered an almost inert cellular structure that protected the protoplast against osmotic offense, more recent studies have demonstrated that it is a dynamic organelle. The major components of the cell wall are glucan and chitin, which are associated with structural rigidity, and mannoproteins. The protein component, including both mannoprotein and nonmannoproteins, comprises some 40 or more moieties. Wall proteins may differ in their expression, secretion, or topological location within the wall structure. Proteins may be modified by glycosylation (primarily addition of mannose residues), phosphorylation, and ubiquitination. Among the secreted enzymes are those that are postulated to have substrates within the cell wall and those that find substrates in the extracellular environment. Cell wall proteins have been implicated in adhesion to host tissues and ligands. Fibrinogen, complement fragments, and several extracellular matrix components are among the host proteins bound by cell wall proteins. Proteins related to the hsp70 and hsp90 families of conserved stress proteins and some glycolytic enzyme proteins are also found in the cell wall, apparently as bona fide components. In addition, the expression of some proteins is associated with the morphological growth form of the fungus and may play a role in morphogenesis. Finally, surface mannoproteins are strong immunogens that trigger and modulate the host immune response during candidiasis. PMID:9529890

Extracellular Vesicle-Associated Transitory Cell Wall Components and Their Impact on the Interaction of Fungi with Host Cells.

PubMed

Nimrichter, Leonardo; de Souza, Marcio M; Del Poeta, Maurizio; Nosanchuk, Joshua D; Joffe, Luna; Tavares, Patricia de M; Rodrigues, Marcio L

2016-01-01

Classic cell wall components of fungi comprise the polysaccharides glucans and chitin, in association with glycoproteins and pigments. During the last decade, however, system biology approaches clearly demonstrated that the composition of fungal cell walls include atypical molecules historically associated with intracellular or membrane locations. Elucidation of mechanisms by which many fungal molecules are exported to the extracellular space suggested that these atypical components are transitorily located to the cell wall. The presence of extracellular vesicles (EVs) at the fungal cell wall and in culture supernatants of distinct pathogenic species suggested a highly functional mechanism of molecular export in these organisms. Thus, the passage of EVs through fungal cell walls suggests remarkable molecular diversity and, consequently, a potentially variable influence on the host antifungal response. On the basis of information derived from the proteomic characterization of fungal EVs from the yeasts Cryptoccocus neoformans and Candida albicans and the dimorphic fungi Histoplasma capsulatum and Paracoccidioides brasiliensis, our manuscript is focused on the clear view that the fungal cell wall is much more complex than previously thought.

Elevated Cell Wall Serine in Pleiotropic Staphylococcal Mutants

PubMed Central

Korman, Ruth Z.

1966-01-01

Korman, Ruth Z. (Cornell University, Ithaca, N.Y.). Elevated cell wall serine in pleiotropic staphylococcal mutants. J. Bacteriol. 92:762–768. 1966.—Physically purified cell walls were prepared from two staphylococcal strains and from pleiotropic variants derived from them. The quantitative amino acid and amino sugar content of these walls is reported. The pleiotypes, which are identified culturally by their failure to elaborate coagulase, their resistance to bacteriophage, and their sensitivity to mannitol, have altered molar ratios of amino acids and amino sugars in their cell walls. In comparison with lysine content, the serine content of the mutant wall is elevated and the glycine content is reduced. The glucosamine content is reduced also. It is postulated that the pleiotropic mutants possess an altered cell wall biosynthetic pathway. Images PMID:5922547

Chitinase and chitin synthase 1: counterbalancing activities in cell separation of Saccharomyces cerevisiae.

PubMed

Cabib, E; Silverman, S J; Shaw, J A

1992-01-01

Previous results [E. Cabib, A. Sburlati, B. Bowers & S. J. Silverman (1989) Journal of Cell Biology 108, 1665-1672] strongly suggested that the lysis observed in daughter cells of Saccharomyces cerevisiae defective in chitin synthase 1 (Chs1) was caused by a chitinase that partially degrades the chitin septum in the process of cell separation. Consequently, it was proposed that in wild-type cells, Chs1 acts as a repair enzyme by replenishing chitin during cytokinesis. The chitinase requirement for lysis has been confirmed in two different ways: (a) demethylallosamidin, a more powerful chitinase inhibitor than the previously used allosamidin, is also a much better protector against lysis and (b) disruption of the chitinase gene in chs1 cells eliminates lysis. Reintroduction of a normal chitinase gene, by transformation of those cells with a suitable plasmid, restores lysis. The percentage of lysed cells in strains lacking Chs1 was not increased by elevating the chitinase level with high-copy-number plasmids carrying the hydrolase gene. Furthermore, the degree of lysis varied in different chs1 strains; lysis was abolished in chs1 mutants containing the scs1 suppressor. These results indicate that, in addition to chitinase, lysis requires other gene products that may become limiting.

Binary Gene Expression Patterning of the Molt Cycle: The Case of Chitin Metabolism

PubMed Central

Abehsera, Shai; Glazer, Lilah; Tynyakov, Jenny; Plaschkes, Inbar; Chalifa-Caspi, Vered; Khalaila, Isam; Aflalo, Eliahu D.; Sagi, Amir

2015-01-01

In crustaceans, like all arthropods, growth is accompanied by a molting cycle. This cycle comprises major physiological events in which mineralized chitinous structures are built and degraded. These events are in turn governed by genes whose patterns of expression are presumably linked to the molting cycle. To study these genes we performed next generation sequencing and constructed a molt-related transcriptomic library from two exoskeletal-forming tissues of the crayfish Cherax quadricarinatus, namely the gastrolith and the mandible cuticle-forming epithelium. To simplify the study of such a complex process as molting, a novel approach, binary patterning of gene expression, was employed. This approach revealed that key genes involved in the synthesis and breakdown of chitin exhibit a molt-related pattern in the gastrolith-forming epithelium. On the other hand, the same genes in the mandible cuticle-forming epithelium showed a molt-independent pattern of expression. Genes related to the metabolism of glucosamine-6-phosphate, a chitin precursor synthesized from simple sugars, showed a molt-related pattern of expression in both tissues. The binary patterning approach unfolds typical patterns of gene expression during the molt cycle of a crustacean. The use of such a simplifying integrative tool for assessing gene patterning seems appropriate for the study of complex biological processes. PMID:25919476

Identification and characterization of a chitin deacetylase from a metagenomic library of deep-sea sediments of the Arctic Ocean.

PubMed

Liu, Jinlin; Jia, Zhijuan; Li, Sha; Li, Yan; You, Qiang; Zhang, Chunyan; Zheng, Xiaotong; Xiong, Guomei; Zhao, Jin; Qi, Chao; Yang, Jihong

2016-09-15

The chemical and biological compositions of deep-sea sediments are interesting because of the underexplored diversity when it comes to bioprospecting. The special geographical location and climates make Arctic Ocean a unique ocean area containing an abundance of microbial resources. A metagenomic library was constructed based on the deep-sea sediments of Arctic Ocean. Part of insertion fragments of this library were sequenced. A chitin deacetylase gene, cdaYJ, was identified and characterized. A metagenomic library with 2750 clones was obtained and ten clones were sequenced. Results revealed several interesting genes, including a chitin deacetylase coding sequence, cdaYJ. The CdaYJ is homologous to some known chitin deacetylases and contains conserved chitin deacetylase active sites. CdaYJ protein exhibits a long N-terminal and a relative short C-terminal. Phylogenetic analysis revealed that CdaYJ showed highest homology to CDAs from Alphaproteobacteria. The cdaYJ gene was subcloned into the pET-28a vector and the recombinant CdaYJ (rCdaYJ) was expressed in Escherichia coli BL21 (DE3). rCdaYJ showed a molecular weight of 43kDa, and exhibited deacetylation activity by using p-nitroacetanilide as substrate. The optimal pH and temperature of rCdaYJ were tested as pH7.4 and 28°C, respectively. The construction of metagenomic library of the Arctic deep-sea sediments provides us an opportunity to look into the microbial communities and exploiting valuable gene resources. A chitin deacetylase CdaYJ was identified from the library. It showed highest deacetylation activity under slight alkaline and low temperature conditions. CdaYJ might be a candidate chitin deacetylase that possesses industrial and pharmaceutical potentials. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of a chitin-binding vicilin from Enterolobium contortisiliquum seeds on bean bruchid pests (Callosobruchus maculatus and Zabrotes subfasciatus) and phytopathogenic fungi (Fusarium solani and Colletrichum lindemuntianum).

PubMed

Moura, Fabiano T; Oliveira, Adeliana S; Macedo, Leonardo L P; Vianna, André L B R; Andrade, Lucia B S; Martins-Miranda, A S; Oliveira, Jose T A; Santos, Elizeu A; de Sales, Mauricio P

2007-01-24

Chitin-binding vicilin from Enterolobium contortisiliquum seeds was purified by ammonium sulfate followed by gel filtration on Sephacryl 300-SH and on Sephacryl 200-SH. The vicilin, called EcV, is a dimeric glycoprotein composed of 1.03% carbohydrates and a Mr of 151 kDa, consisting of two subunits of Mr of 66.2 and 63.8 kDa. The EcV homogeneity was confirmed in a PAGE where it was observed to be a unique acid protein band with slow mobility in this native gel. E. contortisiliquum vicilin (EcV) was tested for anti-insect activity against C. maculatus and Zabrotes subfasciatus larvae and for phytopathogenic fungi, F. solani and C. lindemuntianum. EcV was very effective against both bruchids, producing 50% mortality for Z. subfasciatus at an LD50 of 0.43% and affected 50% of the larvae mass with an ED50 of 0.65%. In artificial diets given to C. maculatus, 50% of the larvae mass was affected with an ED50 of 1.03%, and larva mortality was 50% at LD50 of 1.11%. EcV was not digested by midgut homogenates of C. maculatus and Z. Subfasciatus until 12 h of incubation, and at 24 h EcV was more resistant to Z. subfasciatus larval proteases. The binding to chitin present in larvae gut associated to low EcV digestibility could explain its lethal effects. EcV also exerted an inhibitory effect on the germination of F. solani at concentrations of 10 and 20 microg mL-1. The effect of EcV on fungi is possibly due to binding to chitin-containing structures of the fungal cell wall.

Inhibition of chitin biosynthesis in cultured imaginal discs: Effects of alpha-amanitin, actinomycin-D, cycloheximide, and puromycin.

PubMed

Oberlander, Herbert; Ferkovich, Stephen; Leach, Eddie; Van Essen, Frank

1980-02-01

Wing imaginal discs isolated from last instar larvae of the Indian meal moth,Plodia interpunctella, produced chitin when incubated in vitro with ≧2×10 -7 M 20-hydroxyecdysone. Chitin biosynthesis was initiated 8 h after the conclusion of a 24-h treatment with hormone. Simulataneous incubation of wing discs with 20-hydroxyecdysone and either inhibitors of RNA synthesis (alpha-amanitin, actinomycin-D) or inhibitors of protein systhesis (cycloheximide, puromycin) prevented chitin biosynthesis. We conclude from our results that RNA and protein synthesis must continue undiminished during the hormone-contact period, and that synthesis of protein, but not of new RNA is required during the posthormone culture period. Our findings are consistent with the hypothesis that ecdysteroids stimulate insect metamorphosis by promoting the synthesis of new RNA and protein during a hormone-dependent phase followed by hormone-independent protein synthesis.

Improved fluorescent labeling of chitin oligomers: Chitinolytic properties of acidic mammalian chitinase under somatic tissue pH conditions.

PubMed

Wakita, Satoshi; Kimura, Masahiro; Kato, Naoki; Kashimura, Akinori; Kobayashi, Shunsuke; Kanayama, Naoto; Ohno, Misa; Honda, Shotaro; Sakaguchi, Masayoshi; Sugahara, Yasusato; Bauer, Peter O; Oyama, Fumitaka

2017-05-15

Acidic mammalian chitinase (AMCase) has been implicated in various pathophysiological conditions including asthma, allergic inflammation and food processing. AMCase is most active at pH 2.0, and its activity gradually decreases to up to pH 8. Here we analyzed chitin degradation by AMCase in weak acidic to neutral conditions by fluorophore-assisted carbohydrate electrophoresis established originally for oligosaccharides analysis. We found that specific fragments with slower-than-expected mobility as defined by chitin oligosaccharide markers were generated at pH 5.0∼8.0 as by-products of the reaction. We established an improved method for chitin oligosaccharides suppressing this side reaction by pre-acidification of the fluorophore-labeling reaction mixture. Our improved method specifically detects chitin oligosaccharides and warrants quantification of up to 50nmol of the material. Using this strategy, we found that AMCase produced dimer of N-acetyl-d-glucosamine (GlcNAc) at strong acidic to neutral condition. Moreover, we found that AMCase generates (GlcNAc) 2 as well as (GlcNAc) 3 under physiological conditions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Receptor-mediated chitin perception in legume roots is functionally separable from Nod factor perception.

PubMed

Bozsoki, Zoltan; Cheng, Jeryl; Feng, Feng; Gysel, Kira; Vinther, Maria; Andersen, Kasper R; Oldroyd, Giles; Blaise, Mickael; Radutoiu, Simona; Stougaard, Jens

2017-09-19

The ability of root cells to distinguish mutualistic microbes from pathogens is crucial for plants that allow symbiotic microorganisms to infect and colonize their internal root tissues. Here we show that Lotus japonicus and Medicago truncatula possess very similar LysM pattern-recognition receptors, Lj LYS6/ Mt LYK9 and Mt LYR4, enabling root cells to separate the perception of chitin oligomeric microbe-associated molecular patterns from the perception of lipochitin oligosaccharide by the Lj NFR1/ Mt LYK3 and Lj NFR5/ Mt NFP receptors triggering symbiosis. Inactivation of chitin-receptor genes in Ljlys6 , Mtlyk9 , and Mtlyr4 mutants eliminates early reactive oxygen species responses and induction of defense-response genes in roots. Ljlys6 , Mtlyk9 , and Mtlyr4 mutants were also more susceptible to fungal and bacterial pathogens, while infection and colonization by rhizobia and arbuscular mycorrhizal fungi was maintained. Biochemical binding studies with purified Lj LYS6 ectodomains further showed that at least six GlcNAc moieties (CO6) are required for optimal binding efficiency. The 2.3-Å crystal structure of the Lj LYS6 ectodomain reveals three LysM βααβ motifs similar to other LysM proteins and a conserved chitin-binding site. These results show that distinct receptor sets in legume roots respond to chitin and lipochitin oligosaccharides found in the heterogeneous mixture of chitinaceous compounds originating from soil microbes. This establishes a foundation for genetic and biochemical dissection of the perception and the downstream responses separating defense from symbiosis in the roots of the 80-90% of land plants able to develop rhizobial and/or mycorrhizal endosymbiosis.

Chitin and chitosan from the Norway lobster by-products: Antimicrobial and anti-proliferative activities.

PubMed

Sayari, Nadhem; Sila, Assaâd; Abdelmalek, Baha Eddine; Abdallah, Rihab Ben; Ellouz-Chaabouni, Semia; Bougatef, Ali; Balti, Rafik

2016-06-01

Chitin was recovered through enzymatic deproteinization of the Norway lobster (Nephrops norvegicus) processing by-products. The obtained chitin was characterized and converted into chitosan by N-deacetylation, the acid-soluble form of chitin. Chitosan samples were then characterized by Fourier transform infrared spectroscopy (FTIR) and 13 Cross polarization magic angle spinning nuclear magnetic resonance (CP/MAS)-NMR spectroscopy. The antimicrobial activity and anti-proliferative capacity of chitosan were evaluated. Antimicrobial activity assays indicated that prepared chitosan exhibited marked inhibitory activity against the bacterial and fungal strains tested. Further, cytotoxic effects of chitosan samples on human colon carcinoma cells HCT116 was evaluated using the MTT assay. Chitosan showed the antiproliferative capacity against the colon-cancer-cell HCT116 in a dose dependent manner with IC50 of 4.6mg/ml. Indeed, HCT116 cell proliferation was significantly inhibited (p<0.05) between 13.5 and 67.5% at 0.5-6mg/mL of chitosan after 24h of cell treatment. The chitosan showed high antitumor activity which seemed to be dependent on its characteristics such as acetylation degree. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of green method for chitin deacetylation

NASA Astrophysics Data System (ADS)

Anwar, Muslih; Anggraeni, Ayu Septi; Amin, M. Harisuddin Al

2017-03-01

Developing highly environmentally friendly and cost-effective approaches for the chitosan production has paramount important in the future technology. Deacetylation process is one of the most importing steps to classify the quality of chitosan. This research aimed to study the best method for deacetylation of chitin considered by several factors like the concentration of base, temperature, time and reaction method. From the green chemistry point of view, conventional refluxing method relatively wasted energy compared to another method such as maceration, grinding and sonication. The degree of deacetylation (DD) of chitosan was studied by sonication, resulted in slightly increasing of DD from 73.14 to 73.28% during the time from 0.5 h to 1 h. Deacetylation of chitin with various sodium hydroxide concentration 60, 70 and 80% gave 73.14, 76.36 and 77.88% of DD, respectively. Variation of temperature at 40, 60, and 80 °C was slightly affected on increasing DD from 67.53, 72.84 and 73.14%, respectively. The DD of chitosan significantly increased from 60.19, 74.27 and 81.20% respectively correspondent to varying NaOH concentration 60, 70 and 80% using the maceration method. Solid phase grinding method for half hour resulted in 79.49% of DD. The application of ultrasound grinding method not only was enhanced toward the deacetylation but also favoured the depolymerization process. Moreover, maceration for 7 days with 80% NaOH can be as an alternative method.

Disruption of Bcchs4, Bcchs6 or Bcchs7 chitin synthase genes in Botrytis cinerea and the essential role of class VI chitin synthase (Bcchs6).

PubMed

Morcx, Serena; Kunz, Caroline; Choquer, Mathias; Assie, Sébastien; Blondet, Eddy; Simond-Côte, Elisabeth; Gajek, Karina; Chapeland-Leclerc, Florence; Expert, Dominique; Soulie, Marie-Christine

2013-03-01

Chitin synthases play critical roles in hyphal development and fungal pathogenicity. Previous studies on Botrytis cinerea, a model organism for necrotrophic pathogens, have shown that disruption of Bcchs1 and more particularly Bcchs3a genes have a drastic impact on virulence (Soulié et al., 2003, 2006). In this work, we investigate the role of other CHS including BcCHS4, BcCHS6 and BcCHS7 during the life cycle of B. cinerea. Single deletions of corresponding genes were carried out. Phenotypic analysis indicates that: (i) BcCHS4 enzyme is not essential for development and pathogenicity of the fungus; (ii) BcCHS7 is required for pathogenicity in a host dependant manner. For Bcchs6 gene disruption, we obtained only heterokaryotic strains. Indeed, sexual or asexual purification assays were unsuccessful. We concluded that class VI chitin synthase could be essential for B. cinerea and therefore BcCHS6 represents a valuable antifungal target. Copyright © 2012 Elsevier Inc. All rights reserved.

Enzyme activity and expression pattern of intra- and extracellular chitinase and β-1,3-glucanase of Wickerhamomyces anomalus EG2 using glycol chitin and glucan-containing high polymer complex.

PubMed

Hong, Sin-Hyoung; Song, Yong-Su; Seo, Dong-Jun; Kim, Kil-Yong; Jung, Woo-Jin

2017-12-01

We investigated cell growth and activity of intra- and extracellular chitinase, β-1,3-glucanase, and chitin deacetylase with SDS-PAGE by incubating W. anomalus EG2 in PDB and YPD media for 24h in presence of different concentrations (0%, 0.1%, 0.3%, and 0.5%) of colloidal chitin. Maximum cell growth was observed in both PDB and YPD media without colloidal chitin. In the absence of colloidal chitin, maximum extracellular β-1,3-glucanase activity of 32.96 and 47.28 units/mL was reported at 18h in PDB medium and 6h in YPD medium, respectively. In addition, extracellular chitinase was unaffected by various concentrations of carboxymethyl chitin in both PDB and YPD media. In the absence of colloidal chitin, maximum intracellular chitinase activity was indicated to be 9.82 and 9.86 units/mg protein in PDB and YPD media, respectively. Maximum intracellular β-1,3-glucanase activity reported was 17.34 units/mg protein in PDB medium containing 0.5% colloidal chitin and 15.0 units/mg protein in YPD medium containing 0.3% colloidal chitin. Five major isozymes, GN1, GN2, GN3, GN4, and GN5, of intracellular β-1,3-glucanase were detected with glucan-containing high polymer complex as a substrate with or without colloidal chitin. Copyright © 2017 Elsevier B.V. All rights reserved.

Sporothrix schenckii sensu stricto and Sporothrix brasiliensis Are Differentially Recognized by Human Peripheral Blood Mononuclear Cells

PubMed Central

Martínez-Álvarez, José A.; Pérez-García, Luis A.; Mellado-Mojica, Erika; López, Mercedes G.; Martínez-Duncker, Iván; Lópes-Bezerra, Leila M.; Mora-Montes, Héctor M.

2017-01-01

Sporothrix schenckii sensu stricto and S. brasiliensis are usually associated to sporotrichosis, a subcutaneous mycosis worldwide distributed. Comparative analyses between these two species indicate they contain genetic and physiological differences that are likely to impact the interaction with host cells. Here, we study the composition of the cell wall from conidia, yeast-like cells and germlings of both species and found they contained the same sugar composition. The carbohydrate proportion in the S. schenckii sensu stricto wall was similar across the three cell morphologies, with exception in the chitin content, which was significantly different in the three morphologies. The cell wall from germlings showed lower rhamnose content and higher glucose levels than other cell morphologies. In S. brasiliensis, the wall sugars were constant in the three morphologies, but glucose was lower in yeast-like cells. In S. schenckii sensu stricto cells most of chitin and β1,3-glucan were underneath wall components, but in S. brasiliensis germlings, chitin was exposed at the cell surface, and β1,3-glucan was found in the outer part of the conidia wall. We also compared the ability of these cells to stimulate cytokine production by human peripheral blood mononuclear cells. The three S. schenckii sensu stricto morphologies stimulated increased levels of pro-inflammatory cytokines, when compared to S. brasiliensis cells; while the latter, with exception of conidia, stimulated higher IL-10 levels. Dectin-1 was a key receptor for cytokine production during stimulation with the three morphologies of S. schenckii sensu stricto, but dispensable for cytokine production stimulated by S. brasiliensis germlings. TLR2 and TLR4 were also involved in the sensing of Sporothrix cells, with a major role for the former during cytokine stimulation. Mannose receptor had a minor contribution during cytokine stimulation by S. schenckii sensu stricto yeast-like cells and germlings, but S. schenckii

Morphological changes of the filamentous fungus Mucor mucedo and inhibition of chitin synthase activity induced by anethole.

PubMed

Yutani, Masahiro; Hashimoto, Yukie; Ogita, Akira; Kubo, Isao; Tanaka, Toshio; Fujita, Ken-ichi

2011-11-01

trans-Anethole (anethole), a major component of anise oil, has a broad antimicrobial spectrum with antimicrobial activity relatively weaker than those of well-known antibiotics, and significantly enhances the antifungal activity of polygodial and dodecanol against the baker's yeast Saccharomyces cerevisiae and human pathogenic yeast Candida albicans. However, the antifungal mechanism of anethole is unresolved. Anethole demonstrated antifungal activity against the filamentous fungus, Mucor mucedo IFO 7684, accompanied by hyphal morphological changes such as swollen hyphae at the tips. Its minimum growth inhibitory concentration was 0.625 mM. A hyperosmotic condition (1.2 M sorbitol) restricted the induction of morphological changes, while hypoosmotic treatment (distilled water) induced bursting of hyphal tips and leakage of cytoplasmic constituents. Furthermore, anethole dose-dependently inhibited chitin synthase (CHS) activity in permeabilized hyphae in an uncompetitive manner. These results suggest that the morphological changes of M. mucedo could be explained by the fragility of cell walls caused by CHS inhibition. Copyright © 2011 John Wiley & Sons, Ltd.

Novel chitin scaffolds derived from marine sponge Ianthella basta for tissue engineering approaches based on human mesenchymal stromal cells: Biocompatibility and cryopreservation.

PubMed

Mutsenko, Vitalii V; Gryshkov, Oleksandr; Lauterboeck, Lothar; Rogulska, Olena; Tarusin, Dmitriy N; Bazhenov, Vasilii V; Schütz, Kathleen; Brüggemeier, Sophie; Gossla, Elke; Akkineni, Ashwini R; Meißner, Heike; Lode, Anja; Meschke, Stephan; Fromont, Jane; Stelling, Allison L; Tabachnik, Konstantin R; Gelinsky, Michael; Nikulin, Sergey; Rodin, Sergey; Tonevitsky, Alexander G; Petrenko, Alexander Y; Glasmacher, Birgit; Schupp, Peter J; Ehrlich, Hermann

2017-11-01

The extraordinary biocompatibility and mechanical properties of chitinous scaffolds from marine sponges endows these structures with unique properties that render them ideal for diverse biomedical applications. In the present work, a technological route to produce "ready-to-use" tissue-engineered products based on poriferan chitin is comprehensively investigated for the first time. Three key stages included isolation of scaffolds from the marine demosponge Ianthella basta, confirmation of their biocompatibility with human mesenchymal stromal cells, and cryopreservation of the tissue-like structures grown within these scaffolds using a slow cooling protocol. Biocompatibility of the macroporous, flat chitin scaffolds has been confirmed by cell attachment, high cell viability and the ability to differentiate into the adipogenic lineage. The viability of cells cryopreserved on chitin scaffolds was reduced by about 30% as compared to cells cryopreserved in suspension. However, the surviving cells were able to retain their differentiation potential; and this is demonstrated for the adipogenic lineage. The results suggest that chitin from the marine demosponge I. basta is a promising, highly biocompatible biomaterial for stem cell-based tissue-engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Morintides: cargo-free chitin-binding peptides from Moringa oleifera.

PubMed

Kini, Shruthi G; Wong, Ka H; Tan, Wei Liang; Xiao, Tianshu; Tam, James P

2017-03-31

Hevein-like peptides are a family of cysteine-rich and chitin-binding peptides consisting of 29-45 amino acids. Their chitin-binding property is essential for plant defense against fungi. Based on the number of cysteine residues in their sequences, they are divided into three sub-families: 6C-, 8C- and 10C-hevein-like peptides. All three subfamilies contain a three-domain precursor comprising a signal peptide, a mature hevein-like peptide and a C-terminal domain comprising a hinge region with protein cargo in 8C- and 10C-hevein-like peptides. Here we report the isolation and characterization of two novel 8C-hevein-like peptides, designated morintides (mO1 and mO2), from the drumstick tree Moringa oleifera, a drought-resistant tree belonging to the Moringaceae family. Proteomic analysis revealed that morintides comprise 44 amino acid residues and are rich in cysteine, glycine and hydrophilic amino acid residues such as asparagine and glutamine. Morintides are resistant to thermal and enzymatic degradation, able to bind to chitin and inhibit the growth of phyto-pathogenic fungi. Transcriptomic analysis showed that they contain a three-domain precursor comprising an endoplasmic reticulum (ER) signal sequence, a mature peptide domain and a C-terminal domain. A striking feature distinguishing morintides from other 8C-hevein-like peptides is a short and protein-cargo-free C-terminal domain. Previously, a similar protein-cargo-free C-terminal domain has been observed only in ginkgotides, the 8C-hevein-like peptides from a gymnosperm Ginkgo biloba. Thus, morintides, with a cargo-free C-terminal domain, are a stand-alone class of 8C-hevein-like peptides from angiosperms. Our results expand the existing library of hevein-like peptides and shed light on molecular diversity within the hevein-like peptide family. Our work also sheds light on the anti-fungal activity and stability of 8C-hevein-like peptides.

Bio-responsive chitin-poly(L-lactic acid) composite nanogels for liver cancer.

PubMed

Arunraj, T R; Sanoj Rejinold, N; Ashwin Kumar, N; Jayakumar, R

2014-01-01

Hepatic carcinoma (HCC) is one of the most common cancer and its treatment has been considered a therapeutic challenge. Doxorubicin (Dox) is one of the most important chemotherapeutic agents used in the treatment for liver cancer. However, the efficacy of Dox therapy is restricted by the dose-dependent toxic side effects. To overcome the cardiotoxicity of Dox as well as the current problems of conventional modality treatment of HCC, we developed a locally injectable, biodegradable, and pH sensitive composite nanogels for site specific delivery. Both control and Dox loaded composite nanogel systems were analyzed by DLS, SEM, FTIR and TG/DTA. The size ranges of the control composite nanogels and their drug loaded counterparts were found to be 90±20 and 270±20 nm, respectively. The control chitin-PLA CNGs and Dox-chitin-PLA CNGs showed higher swelling and degradation in acidic pH. Drug entrapment efficiency and in vitro drug release studies were carried out and showed a higher drug release at acidic pH compared to neutral pH. Cellular internalization of the nanogel systems was confirmed by fluorescent microscopy. The cytotoxicity of the composite nanogels was analyzed toward HepG2 (human liver cancer) cell lines. Furthermore, the results of in vitro hemolytic assay and coagulation assay substantiate the blood compatibility of the system. Overall Dox-chitin-PLA CNGs system could be a promising anticancer drug delivery system for liver cancer therapy. Copyright © 2013 Elsevier B.V. All rights reserved.

Abnormal swelling of the peritrophic membrane in Eri silkworm gut caused by MLX56 family defense proteins with chitin-binding and extensin domains.

PubMed

Konno, Kotaro; Shimura, Sachiko; Ueno, Chihiro; Arakawa, Toru; Nakamura, Masatoshi

2018-03-01

MLX56 family defense proteins, MLX56 and its close homolog LA-b, are chitin-binding defense proteins found in mulberry latex that show strong growth-inhibitions against caterpillars when fed at concentrations as low as 0.01%. MLX56 family proteins contain a unique structure with an extensin domain surrounded by two hevein-like chitin-binding domains, but their defensive modes of action remain unclear. Here, we analyzed the effects of MLX56 family proteins on the peritrophic membrane (PM), a thin and soft membrane consisting of chitin that lines the midgut lumen of insects. We observed an abnormally thick (>1/5 the diameter of midgut) hard gel-like membrane consisted of chitin and MLX56 family proteins, MLX56 and LA-b, in the midgut of the Eri silkworms, Samia ricini, fed a diet containing MLX56 family proteins, MLX56 and LA-b. When polyoxin AL, a chitin-synthesis-inhibitor, was added to the diet containing MLX56 family proteins, the toxicity of MLX56 family proteins disappeared and PM became thinner and fragmented. These results suggest that MLX56 family proteins, through their chitin-binding domains, bind to the chitin framework of PM, then through their extensin-domain (gum arabic-like structure), which functions as swelling agent, expands PM into an abnormally thick membrane that inhibits the growth of insects. This study shows that MLX56 family proteins are plant defense lectins with a totally unique mode of action, and reveals the functions of extensin domains and arabinogalactan proteins as swelling (gel-forming) agents of plants. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enzymatic hydrolysis of chitin pretreated by rapid depressurization from supercritical 1,1,1,2-tetrafluoroethane toward highly acetylated oligosaccharides.

PubMed

Villa-Lerma, Guadalupe; González-Márquez, Humberto; Gimeno, Miquel; Trombotto, Stéphane; David, Laurent; Ifuku, Shinsuke; Shirai, Keiko

2016-06-01

The hydrolysis of chitin treated under supercritical conditions was successfully carried out using chitinases obtained by an optimized fermentation of the fungus Lecanicillium lecanii. The biopolymer was subjected to a pretreatment based on suspension in supercritical 1,1,1,2-tetrafluoroethane (scR134a), which possesses a critical temperature and pressure of 101°C and 40bar, respectively, followed by rapid depressurization to atmospheric pressure and further fibrillation. This methodology was compared to control untreated chitins and chitin subjected to steam explosion showing improved production of reducing sugars (0.18mg/mL), enzymatic hydrolysis and high acetylation (FA of 0.45) in products with degrees of polymerization between 2 and 5. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Antifungal Activity of Functionalized Chitin Nanocrystals in Poly (Lactid Acid) Films

PubMed Central

Salaberria, Asier M.; H. Diaz, Rene; Andrés, María A.; Fernandes, Susana C.M.; Labidi, Jalel

2017-01-01

As, in the market, poly (lactic acid) (PLA) is the most used polymer as an alternative to conventional plastics, and as functionalized chitin nanocrystals (CHNC) can provide structural and bioactive properties, their combination sounds promising in the preparation of functional nanocomposite films for sustainable packaging. Chitin nanocrystals were successfully modified via acylation using anhydride acetic and dodecanoyl chloride acid to improve their compatibility with the matrix, PLA. The nanocomposite films were prepared by extrusion/compression approach using different concentrations of both sets of functionalized CHNC. This investigation brings forward that both sets of modified CHNC act as functional agents, i.e., they slightly improved the hydrophobic character of the PLA nanocomposite films, and, very importantly, they also enhanced their antifungal activity. Nonetheless, the nanocomposite films prepared with the CHNC modified with dodecanoyl chloride acid presented the best properties. PMID:28772902

Multiple chitinases of an endophytic Serratia proteamaculans 568 generate chitin oligomers.

PubMed

Purushotham, Pallinti; Sarma, P V S R N; Podile, Appa Rao

2012-05-01

Serratia proteamaculans 568 genome revealed the presence of four family 18 chitinases (Sp ChiA, Sp ChiB, Sp ChiC, and Sp ChiD). Heterologous expression and characterization of Sp ChiA, Sp ChiB, and Sp ChiC showed that these enzymes were optimally active at pH 6.0-7.0, and 40°C. The three Sp chitinases displayed highest activity/binding to β-chitin and showed broad range of substrate specificities, and released dimer as major end product from oligomeric and polymeric substrates. Longer incubation was required for hydrolysis of trimer for the three Sp chitinases. The three Sp chitinases released up to tetramers from colloidal chitin substrate. Sp ChiA and Sp ChiB were processive chitinases, while Sp ChiC was a non-processive chitinase. Based on the known structures of ChiA and ChiB from S. marcescens, 3D models of Sp ChiA and Sp ChiB were generated. Copyright © 2012 Elsevier Ltd. All rights reserved.

Bioconversion of α-chitin into N-acetyl-glucosamine using chitinases produced by marine-derived Aeromonas caviae isolates.

PubMed

Cardozo, Flávio Augusto; Gonzalez, Juan Miguel; Feitosa, Valker Araujo; Pessoa, Adalberto; Rivera, Irma Nelly Gutierrez

2017-10-27

N-Acetyl-D-glucosamine (GlcNAc) is a monosaccharide with great application potential in the food, cosmetic, pharmaceutical, and biomaterial areas. GlcNAc is currently produced by chemical hydrolysis of chitin, but the current processes are environmentally unfriendly, have low yield and high cost. This study demonstrates the potential to produce GlcNAc from α-chitin using chitinases of ten marine-derived Aeromonas isolates as a sustainable alternative to the current chemical process. The isolates were characterized as Aeromonas caviae by multilocus sequence analysis (MLSA) using six housekeeping genes (gltA, groL, gyrB, metG, ppsA, and recA), not presented the virulence genes verified (alt, act, ast, ahh1, aer, aerA, hlyA, ascV and ascFG), but showed hemolytic activity on blood agar. GlcNAc was produced at 37 °C, pH 5.0, 2% (w/v) colloidal chitin and crude chitinase extracts (0.5 U mL -1 ) by all the isolates with yields from 14 to 85% at 6 h, 17-89% at 12 h and 19-93% after 24 h. The highest yield of GlcNAc was observed by A. caviae CH129 (93%). This study demonstrates one of the most efficient chitin enzymatic hydrolysis procedures and A. caviae isolates with great potential for chitinases expression and GlcNAc production.

Preparation, characterization, drug release and computational modelling studies of antibiotics loaded amorphous chitin nanoparticles.

PubMed

Gayathri, N K; Aparna, V; Maya, S; Biswas, Raja; Jayakumar, R; Mohan, C Gopi

2017-12-01

We present a computational investigation of binding affinity of different types of drugs with chitin nanocarriers. Understanding the chitn polymer-drug interaction is important to design and optimize the chitin based drug delivery systems. The binding affinity of three different types of anti-bacterial drugs Ethionamide (ETA) Methacycline (MET) and Rifampicin (RIF) with amorphous chitin nanoparticles (AC-NPs) were studied by integrating computational and experimental techniques. The binding energies (BE) of hydrophobic ETA, hydrophilic MET and hydrophobic RIF were -7.3kcal/mol, -5.1kcal/mol and -8.1kcal/mol respectively, with respect to AC-NPs, using molecular docking studies. This theoretical result was in good correlation with the experimental studies of AC-drug loading and drug entrapment efficiencies of MET (3.5±0.1 and 25± 2%), ETA (5.6±0.02 and 45±4%) and RIF (8.9±0.20 and 53±5%) drugs respectively. Stability studies of the drug encapsulated nanoparticles showed stable values of size, zeta and polydispersity index at 6°C temperature. The correlation between computational BE and experimental drug entrapment efficiencies of RIF, ETA and MET drugs with four AC-NPs strands were 0.999 respectively, while that of the drug loading efficiencies were 0.854 respectively. Further, the molecular docking results predict the atomic level details derived from the electrostatic, hydrogen bonding and hydrophobic interactions of the drug and nanoparticle for its encapsulation and loading in the chitin-based host-guest nanosystems. The present results thus revealed the drug loading and drug delivery insights and has the potential of reducing the time and cost of processing new antibiotic drug delivery nanosystem optimization, development and discovery. Copyright © 2017 Elsevier Ltd. All rights reserved.