|
Show legend Show as text |
Found 1 structure.
Displayed structure 1
| -4)-b-D-GlcpNAc-(1- | Show graphically |
|
Show legend Show as text |
Structure type: homopolymer
Trivial name: chitin
Compound class: O-polysaccharide, cell wall polysaccharide, glucan, polysaccharide, chitin
Contained glycoepitopes: IEDB_135813,IEDB_137340,IEDB_141807,IEDB_151531,IEDB_153212,IEDB_241099,IEDB_423114,IEDB_423150,SB_74,SB_85
This chapter describes the range of glycan structures and pathways that are found in different parasitic protozoa. All parasitic protists express a range of glycoconjugates that form protective protein-rich or carbohydrate-rich surface coats. Protein-rich coats are typically found on developmental stages that inhabit nonhydrolytic niches, such as the bloodstream and nonacidified intracellular vacuoles. These coats are commonly dominated by a limited repertoire of antigenically diverse proteins that are commonly, but not always, glycosylphosphatidylinositol- (GPI-) anchored and modified with N- or O-glycans. Carbohydrate-rich coats are commonly found on developmental stages that dwell within hydrolytic environments, such as vertebrate and arthropod digestive tracts and lysosomal vacuoles. These coats are dominated by GPI-anchored glycoproteins that are heavily modified with N-glycans, O-glycans, or phosphoglycans. Free GPI glycolipids (not attached to protein) can also be abundant or dominant components of these coats. Some parasitic protists can also form highly resistant cyst stages encased within polysaccharide-rich cell walls. Considerable progress has been made in defining the structures of the surface and intracellular glycans of the parasitic protists, their biosynthesis and the role that individual components play in parasite infectivity.
O-glycosylation, Glycosylphosphatidylinositol, N-glycosylation, protozoan parasites, Phosphoglycosylation
Publication DOI: 10.1016/B978-0-12-374546-0.00012-2The impact of fungal infections on humans is a serious public health issue that has received much less attention than bacterial infection and treatment, despite ever-increasing incidence exacerbated by an increased incidence of immunocompromised individuals in the population. Candida species, in particular, cause some of the most prevalent hospital-related fungal infections. Fungal infections are also detrimental to the well-being of grazing livestock, with milk production in dairy cows, and body and coat condition adversely affected by fungal infections. Fungal cell walls are essential for viability, morphogenesis and pathogenesis: numerous anti-fungal drugs rely on targeting either the cell wall or cell membrane, but the pipeline of available bioactives is limited. There is a clear and unmet need to identify novel targets and develop new classes of anti-fungal agents. This mini review focuses on fungal cell wall structure, composition and biosynthesis in Candida spp., including C. auris. In addition, an overview of current advances in the development of cell wall targeted therapies is considered.
vaccines, glycoproteins, inhibitors, chitin, fungal cell wall
NCBI PubMed ID: 34746525The cell wall of Trichosporon cutaneum consists of 11% protein, 63% neutral carbohydrate, 9% glucosamine and 13% glucuronic acid. The sugars include glucose (32%), mannose (6%) and traces of xylose and galactose. The cell wall was fractionated with alkali to yield a mixture of alkali-soluble matrix components, and an alkali-insoluble glucan associated with chitin. The alkali-insoluble glucan contained a mixture of (1-3) and (1-6) glycosidic linkages. It was only partly susceptible to digestion by the β(1-3) glucanase, Zymolyase. The alkali-soluble fraction contained glucan, mannan and acidic polymers. The glucan was (1-3)-linked with no (1-6) linkages and only trace amounts of (1-3-6)-linked glucose. It was resistant to digestion by Zymolyase. Extensive hydrolysis of this fraction with trifluoroacetic acid released a high-molecular-mass glucuronan which had 1H- and 13C-NMR profiles matching those of the β(1-4) glucuronan, mucoric acid. Xylomannan was purified from isolated cell walls and from whole cells. It contained glucose, mannose, xylose, and D-glucuronic acid. It was very similar in composition and structure to the capsular polysaccharides of Cryptococcus neoformans, and to an extracellular polysaccharide produced by another yeast described as T. cutaneum. Electron microscopy showed that the cell wall of T. cutaneum has a lamellar structure characteristic of a basidiomycetous yeast rather than the electron-dense 'fuzzy coat' seen in Candida albicans.
NCBI PubMed ID: 8245838Deproteinated A. niger biomass contains several covalently bound amino acids. The most abundant are arginine, serine, and proline in molar ratio of 3: 2: 2. One order of magnitude less is the amount of valine, phenylalanine, leucine and glycine. On deacetylation and separation of chitosan from glucan, the main three amino acids remain bound predominantly to chitosan, whereas the hydrophobic amino acids accompany mainly glucan. The presence of arginine could be the cause of stronger basicity of fungal chitosan compared to polyglucosamine.
Publication DOI: 10.1007/BF00805812During the past few years, cyto- and immunocytochemical techniques have been developed and widely used for locating and identifying various molecules in plant cell compartments. The last decade has witnessed tremendous improvements in molecular cytology, thus allowing an accurate in situ detection of various components thought to play important biological functions in the plant metabolism. The use of immunocytochemistry to investigate resistance mechanisms of plants upon pathogen attack has provided key information on the defense strategy that plants elaborate during a host-pathogen interaction. Of the various proteins induced in response to infection, chitinases and β-1,3-glucanases have been the focus of particular attention due to their believed antimicrobial activity through the hydrolysis of the main fungal wall components, chitin and β-1,3-glucans. Attention has also been paid to β-fructosidase, the enzyme that hydrolyzes sucrose into glucose and fructoside. The marked accumulation of this enzyme upon pathogen infection has led to the consideration that infection may greatly influence the metabolic activity of colonized tissues by creating alterations of source-sink relationships. Another facet of the plant's defense strategy that has been the focus of considerable interest is related to the accumulation of structural compounds, such as hydroxyproline-rich glycoproteins and callose, to reinforce the wall architecture, thus decreasing vulnerability to microbial enzymes. A number of alternatives designed to improve plant protection towards pathogen invasion have been suggested. Among these, the production of transgenic plants expressing constitutively a foreign resistance gene and the pretreatment of plants with elicitors of defense reactions have been the subject of intensive studies at the molecular, biochemical, and cytological levels. Results of such studies clearly demonstrate the important contribution that cyto- and immunocytochemical approaches can make to our knowledge of how plants defend themselves and how plant disease resistance can be directly enhanced. These approaches will undoubtedly be active areas for future research in the development of biological control alternatives in which the mode of action of the product used is of key importance.
NCBI PubMed ID: 7626800The cell-wall components of the interface compartment in functioning mycorrhizal roots of maize (Zea mays L. cv. W64A) have been investigated with the use of immunocytochemistry and enzyme/lectin-gold techniques. The distribution of specific cell-wall probes was determined in the apical and differentiated regions of maize roots in the presence and in the absence of the mycorrhizal fungus, Glomus versiforme. Labelling experiments showed that a maize hydroxyproline-rich glycoprotein (HRGP), identified with a specific antibody, was particularly abundant in the apical dividing cells of the root meristem. Cellulose, located with a cellobiohydrolase-gold complex, showed a similar labelling pattern in the walls of both meristematic and differentiated parts of the roots. When the cortex was colonized by the mycorrhizal fungus, the HRGP and cellulose were expressed in two sites: the wall and the interface area created by invagination of the host membrane around the developing fungus. In contrast, in uninfected roots of the same age, they were only present in the inner part of the wall. A specific antibody against β-1,3-glucans demonstrated that these glucans were not laid down at the interface between the plant and fungus, while they appeared to be a skeletal component of the fungal wall, together with chitin.
cell wall, cellulose, β-1, arbuscular mycorrhizae, 3-glucans, hydroxyproline-rich glycoprotein, zea root meristem
Publication DOI: 10.1007/BF00199680Glycosylphosphatidylinositol (GPI) membrane anchors are essential for the integration of yeast cell adhesion proteins into the cell wall, but mature cell-wall proteins are unlikely to be attached directly to the membrane. We thus propose that GPI-anchored glycoprotein forms are intermediates in a process that crosslinks the major components of the cell wall by transglycosylation. This mechanism may be critical for both the biosynthesis and overall architecture of the cell wall.
NCBI PubMed ID: 14731865We have previously shown that mutations in the yeast KNR4 gene resulted in pleiotropic cell wall defects, including resistance to killer 9 toxin, elevated osmotic sensitivity to SDS and increased resistance to zymolyase, a (1→3)-β-glucanase. In this report, we further demonstrated that knr4 mutant cells were more permeable to a chromogenic substrate, X-GAL, suggesting that the mutant cell walls were leakier to certain non-permeable molecules. To determine if these defects resulted from structural changes in the cell walls, we analysed the alkali-insoluble cell wall components using HPLC assays developed for this purpose. Comparative analysis using four isogenic strains from a 'knr4 disrupted' tetrad demonstrated that mutant cell walls contained much less (1→3)-β-glucan and (1→6)-β-glucan; however, the level of chitin, a minor cell wall component, was found to be five times higher in the mutant strains compared to the wild-type strains. The data suggested that the knr4 mutant cell walls were dramatically weakened, which may explain the pleiotropic cell wall defects.
NCBI PubMed ID: 7992508In recent years it has become evident that the structural polysaccharide chitin is synthesized from a family of enzymes encoded by multiple CHS chitin synthase genes, and regulated by an array of ancillary gene products that influence CHS activation and localization. Considerable attention has therefore been given to elucidating the function of specific CHS gene products in individual fungi. In those fungi in which individual CHS genes have been deleted systematically, there is little evidence for redundancy of function in family members. Chs enzymes are now known that participate in lateral wall biosynthesis, septum synthesis and spore formation but the phenotype of some CHS gene mutations is subtle, and so the role of the corresponding isoenzymes remains obscure. Nonetheless, it has become clear that certain members of the CHS gene families of fungi are more important for growth, integrity and viability than others, and this knowledge has already led to the design of new classes of antifungal agents that are targeted against key enzyme activities. Future work in this area will help define how individual Chs enzymes are targeted to specific regions of the cell wall and at specific times of the cell cycle, and should facilitate the rational development of novel and highly specific antifungal agents.
cell wall, mutagenesis, morphogenesis, antifungal drugs, chitin synthesis
Publication DOI: 10.1080/mmy.39.1.41.53N-Acetylchitooligosaccharides (oligochitin, chitin oligosaccharides) of a specific size can act as potent elicitor signals for suspension-cultured rice cells as well as various plant cells which include many monocots and some dicots. We recently isolated and characterized a highly elicitor-active glucopentaose from the cell wall P-Glucan from rice blast disease fungus. The results indicated that rice and soybean cells recognize different structural units of fugal glucans as elicitor signals. Because this elicitor treatment can induce many defense reactions, it has been serving as an excellent model system for the study of the signal transduction cascade leading to the activation of defense-related genes. It is critically important to identify and characterize the receptor molecules which perceive the elicitor signal to clarify the whole signal transduction cascade. A 75 kDa chitin oligosaccharide binding protein in the plasma membrane of suspension-cultured rice cells was identified as a putative receptor for the elicitor and purified. Recent studies on the structure and function of the binding proteins for these oligosaccharide elicitors will provide a clue to understanding how these elicitors are perceived and transduced in rice and other plant cells and also how such recognition systems have evolved.
receptor, signal transduction, elicitor
Publication DOI: 10.4052/tigg.12.113Background: To explore chitin synthesis initiation, the effect of addition of exogenous oligosaccharides on in vitro chitin synthesis was studied. Oligosaccharides of various natures and lengths were added to a chitin synthase assay performed on a Saccharomyces cerevisiae membrane fraction. Findings. N-acetylchito-tetra, -penta and -octaoses resulted in 11 to 25% [14C]-GlcNAc incorporation into [14C]-chitin, corresponding to an increase in the initial velocity. The activation appeared specific to N-acetylchitooses as it was not observed with oligosaccharides in other series, such as β-(1,4), β-(1,3) or α-(1,6) glucooligosaccharides. Conclusions: The effect induced by the N-acetylchitooses was a saturable phenomenon and did not interfere with free GlcNAc and trypsin which are two known activators of yeast chitin synthase activity in vitro. The magnitude of the activation was dependent on both oligosaccharide concentration and oligosaccharide size.
Oligosaccharides, glycosyltransferase, chitin synthase, polymerization activation, polysaccharide synthase
NCBI PubMed ID: 22032207Chitin (β-(1-4)-poly-N-acetyl-D-glucosamine) is widely distributed in nature and is the second most abundant polysaccharide after cellulose. Chitin occurs in nature as ordered macrofibrils. It is the major structural component in the exoskeleton of crab and shrimp shells and the cell wall of fungi and yeast. As chitin is not readily dissolved in common solvents, it is often converted to its more deacetylated derivative, chitosan. Chitin, chitosan, and its derivatives are widely used in tissue engineering, wound healing, and as functional foods. Recently, easy methods for the preparation of chitin and chitosan nanofibers have been developed, and studies on biomedical applications of chitin and chitosan nanofibers are ongoing. Chitin and chitosan nanofibers are considered to have great potential for various biomedical applications, because they have several useful properties such as high specific surface area and high porosity. This review summarizes methods for the preparation of chitin and chitosan nanofibers. Further, biomedical applications of chitin and chitosan nanofibers in (i) tissue engineering, (ii) wound dressing, (iii) cosmetic and skin health, (iv) stem cell technology, (v) anti-cancer treatments and drug delivery, (vi) anti-inflammatory treatments, and (vii) obesity treatment are summarized. Many studies indicate that chitin and chitosan nanofibers are suitable materials for various biomedical applications.
drug delivery, cosmetics, chitosan, chitin, obesity, nanofibers, biomedical applications, tissue engineering, stem cells
NCBI PubMed ID: 25992423Chitin synthases (CHS) produce chitin, an essential component of the fungal cell wall. The molecular mechanism of processive chitin synthesis is not understood, limiting the discovery of new inhibitors of this enzyme class. We identified the bacterial glycosyltransferase NodC as an appropriate model system to study the general structure and reaction mechanism of CHS. A high throughput screening-compatible novel assay demonstrates that a known inhibitor of fungal CHS also inhibit NodC. A structural model of NodC, on the basis of the recently published BcsA cellulose synthase structure, enabled probing of the catalytic mechanism by mutagenesis, demonstrating the essential roles of the DD and QXXRW catalytic motifs. The NodC membrane topology was mapped, validating the structural model. Together, these approaches give insight into the CHS structure and mechanism and provide a platform for the discovery of inhibitors for this antifungal target.
cell wall, chitin, chitin synthase
NCBI PubMed ID: 24942743Chitin and β-glucan are conserved throughout evolution in the fungal cell wall and are the most common polysaccharides in fungal species. Together, these two polysaccharides form a structural scaffold that is essential for the survival of the fungus. In the present study, we demonstrated that Aspergillus fumigatus alkali-insoluble cell wall fragments (AIF), composed of chitin linked covalently to β-glucan, induced enhanced immune responses when compared with individual cell wall polysaccharides. Intranasal administration of AIF induced eosinophil and neutrophil recruitment, chitinase activity, TNF-α and TSLP production in mice lungs. Selective destruction of chitin or β-glucan from AIF significantly reduced eosinophil and neutrophil recruitment as well as chitinase activity and cytokine expression by macrophages, indicating the synergistic effect of the cell wall polysaccharides when presented together as a composite PAMP. We also showed that these cell wall polysaccharides induced chitin-specific IgM in mouse serum. Our in vivo and in vitro data indicate that chitin and β-glucan play important roles in activating innate immunity when presented as composite cell wall PAMPs.
inflammation, glucan, innate immunity, lung, chitin, Fungal cell wall polysaccharides
NCBI PubMed ID: 24286790Polysaccharides such as α- and β-glucans, chitin, and glycoproteins extensively modified with both N- and O-linked carbohydrates are the major components of fungal surfaces. The fungal cell wall is an excellent target for the action of antifungal agents, since most of its components are absent from mammalian cells. Recognition of these carbohydrate-containing molecules by the innate immune system triggers inflammatory responses and activation of microbicidal mechanisms by leukocytes. This review will discuss the structure of surface fungal glycoconjugates and polysaccharides and their recognition by innate immune receptors.
glycoconjugates, polysaccharides, innate immunity, fungal pathogens, pattern recognition receptors
NCBI PubMed ID: 25353009Candida albicans is a major life-threatening human fungal pathogen in the immunocompromised host. Host defense against systemic Candida infection relies heavily on the capacity of professional phagocytes of the innate immune system to ingest and destroy fungal cells. A number of pathogens, including C. albicans, have evolved mechanisms that attenuate the efficiency of phagosome-mediated inactivation, promoting their survival and replication within the host. Here we visualize host-pathogen interactions using live-cell imaging and show that viable, but not heat- or UV-killed C. albicans cells profoundly delay phagosome maturation in macrophage cell lines and primary macrophages. The ability of C. albicans to delay phagosome maturation is dependent on cell wall composition and fungal morphology. Loss of cell wall O-mannan is associated with enhanced acquisition of phagosome maturation markers, distinct changes in Rab GTPase acquisition by the maturing phagosome, impaired hyphal growth within macrophage phagosomes, profound changes in macrophage actin dynamics, and ultimately a reduced ability of fungal cells to escape from macrophage phagosomes. The loss of cell wall O-mannan leads to exposure of β-glucan in the inner cell wall, facilitating recognition by Dectin-1, which is associated with enhanced phagosome maturation.
cell wall, β-glucan, Candida albicans, b-glucan
NCBI PubMed ID: 25467440GPI-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 remodelling in pathogenic fungi is limited. In this study, we characterized the role of a putative GPI lipid remodelling 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 remodelling and PerA function in A. fumigatus is a promising research direction to uncover a new fungal specific antifungal drug target.
Aspergillus fumigatus, GPI
NCBI PubMed ID: 24779420The cell wall structure of mushroom sclerotium was investigated by a fractionation of its soluble cell wall polysaccharides followed by chemical, physico-chemical and microscopic analyses. The present results suggest that cell wall structure of Pleurotus tuber regium sclerotium contains three main layers: an outer layer of glycoproteins, a middle layer of hyper-branched glucans and an inner layer of complex between hyper-branched glucan and chitin. The structure of the hyper-branched glucans were elucidated by the methylation analysis to be composed of →1)-Glcp-(4→ linkages as the backbone with some →1)-Glcp(6→ linkages existed in the side chains, while some →1)-Glcp-(3→ linkages might exist in the backbone or side chains. SEC-MALLS analysis revealed that hyper-branched β-glucans had a M-w ranging from 1400000 to 5200000 g/mol and R.M.S. radius ranging from 26 nm to 38.5 nm. SEM and AFM further showed that hyper-branched β-glucans were spherical in shape when dispersed in water.
Publication DOI: 10.1016/j.foodhyd.2013.09.023Within the domain of Eukarya, the fungi form a seperate kingdom. The typical formation of branched mycelia from single hyphae is based on cell wall production at the growing hyphal tip. There, excretory vesicle fuse with the membrane releasing cell wall synthesis enzymes like chitin synthase forming the polymer of N-acetyl glucosamin, the backbone of fungal cell walls. In addition, glucan synthases form the structural component β-1,3-glucan. Via β-1,6-glucan, cell wall proteins can be linked to the maturing cell wall, and α-1,3-glucan can form a matrix within the cell wall, but also a slimy matrix secreted into the medium. A layer of hydrophobins allows for growth into the air, but also facilitates formation of macroscopic structures like mushrooms.
cell wall, glucan, fungi, chitin
Publication DOI: 10.1002/biuz.201610599This study was devoted to polysaccharides extraction (chitin and chitosan) from Penicillium camembertii cell wall. A culture on solid medium was adopted under carefully selected conditions, appropriate to mycelium growth: duration 6 days, medium YPGA and pH 5. The temperature was adjusted (20 °C to 28 °C) in order to study the effect of temperature on chitin/chitosan production. Biomass decreased with increasing temperatures: 13 g/L at 20 °C and 11.6 g/L at 28 °C. For all tested temperatures, the yields of insoluble alkaline fractions (AIM) were almost identical (200 mg/g). The solubility of fractions in 2% acetic acid allowed obtaining two fractions: an insoluble fraction (AcIM) with 18% of maximum yield and soluble fraction (AcSM) with 1% yield. The SEM micrographs of AcIM fractions were similar to AIM fractions. These showed a compact structure different from commercial chitin. The presence of chitin in P. Camembertii cultured in YPGA medium was also confirmed by ATR spectroscopy.
chitin, Biomass, free chitosan, Penicillium camembertii, YPGA
NCBI PubMed ID: 31004649In 1799, Hatchett decalcified shells of crabs, lobsters, prawns and crayfish with mineral acids, observing that they produced a moderate effervescence and in a short time were found to be soft and plastic of a yellowish color and like a cartilage, which retained the original figure. Although this is the first mention of calcified chitin in invertebrates, the discovery of chitin is usually attributed both to Braconnot in 1811 who discovered chitin from fungi, and to Odier in 1823 who obtained a hornlike material after treatment of cockchafer elytra with potassium hydroxide. Chitin was first named fongine by Braconnot and then chitine by Odier. Children revealed the nitrogenous nature of chitin in 1824. The history of chitosan, the main derivative of chitin, dates back to 1859 with the work of Rouget. The name of chitosan was, however, introduced in 1894 by Hoppe-Seyler. In 1876, Ledderhose hydrolyzed arthropod chitin and discovered glykosamin, the first derivative of chitin. This review describes the 220 years of the development of chitin. I have roughly divided the story into five periods: discovery from 1799 to 1894, a period of confusion and controversy from 1894 to 1930, exploration in 1930–1950, a period of doubt from 1950 to 1970, and finally the period of application from 1970. The different periods are illustrated by examples of published studies, in particular from outstanding scholars who have left their mark on the history of this polysaccharide. Although this historic review is not exhaustive, it highlights the work of researchers who have contributed to the development of our knowledge of chitin throughout the 220 years of its history.
History, chitosan, chitin, discovery, Braconnot, controversy, exploration, period of doubt, period of application
Publication DOI: 10.1007/s10311-019-00901-0Chitin is a linear polysaccharide of the amino sugar N-acetyl glucosamine. It is present in the extracellular matrix of a variety of invertebrates including sponges, molluscs, nematodes and arthropods and fungi. Generally, it is an important component of protective or supportive extracellular matrices that cover the tissue that produces it or the whole body of the organism. Chitin fibres associate with each other adopting one of three possible crystalline organisations, i.e. α-, β- or γ-chitin. Usually, chitin fibre bundles interact with chitin-binding proteins forming higher order structures. Chitin laminae, which are two-dimensional sheets of α-chitin crystals with antiparallel running chitin fibres in association with β-folded proteins, are primary constituents of the arthropod cuticle and the fibrous extracellular matrix in sponges. A tri-dimensional composite material of proteins coacervates and β-chitin constitute hard biomaterials such as the squid beak. The molecular composition of γ-chitin-based structures that contribute to the physical barrier found in insect cocoons is less well studied. In principle, chitin is a versatile extracellular polysaccharide that in association with proteins defines the mechanical properties of tissues and organisms.
evolution, Extracellular matrix, barrier, Cuticle, body shape
NCBI PubMed ID: 31102240Chitin is an important structural polysaccharide, which supports and organizes extracellular matrices in a variety of taxonomic groups including bacteria, fungi, protists, and animals. Additionally, chitin has been recognized as a molecule that is required for Rhizobia-legume symbiosis and involved in arbuscular mycorrhizal signaling in the symbiotic interaction between terrestrial plants and fungi. Moreover, it serves as a unique molecular pattern in the plant defense system against pathogenic fungi and parasites, and in the innate and adaptive immune response of mammals and humans. In this review, we will focus on the prevalence and structural function of chitin in bacteria, fungi, and protists, with a particular focus on the evolution of chitin synthases and the function of chitin oligosaccharides as a signaling molecule in symbiosis and immunity.
Rhizobia, cell wall, fungi, protists, skeleton
NCBI PubMed ID: 31102241Chitin is one of the most important carbohydrates of the fungal cell wall, and is synthesized by chitin synthases. Chitin can be degraded by chitinases, which are important virulence factors in pathogenic fungi. Knowledge about the biosynthesis and degradation of chitin, and the enzymes responsible, has accumulated in recent years. In this review, we analyze the amino acid sequences of chitin synthases from several typical fungi. These enzymes can be divided into seven groups. While the different chitin synthases from a single fungus share a low degree of similarity, the same type of chitin synthase from different fungi shows high similarity. The number of chitinase genes in fungi display wide variation, from a single gene in Schizosaccharomyces pombe, to 36 genes in Trichoderma virens. Chitinases from different fungi can be divided into four groups. The functions of chitin synthases and chitinases in several typical fungi are summarized, and the crystal structures of chitinases and chitinase modification are also discussed.
crystal structure, modification, chitin, chitin synthase, chitinase
NCBI PubMed ID: 31102246The traditional yeast Saccharomyces cerevisiae has been widely used as a host for the production of recombinant proteins and metabolites with industrial potential. However, its thick and rigid cell wall presents problems for the effective recovery of products. In this study, we modulated the expression of ScOCH1, encoding the α-1,6-mannosyltransferase responsible for outer chain biosynthesis of N-glycans, and ScCHS3, encoding the chitin synthase III required for synthesis of the majority of cell wall chitin, by exploiting the repressible ScMET3 promoter. The conditional single mutants PMET3-OCH1 and PMET3-CHS3 and the double mutant PMET3-OCH1/PMET3-CHS3 showed comparable growth to the wild-type strain under normal conditions but exhibited increased sensitivity to temperature and cell wall-disturbing agents in the presence of methionine. Such conditional growth defects were fully recovered by supplementation with 1 M sorbitol. The osmotic lysis of the conditional mutants cultivated with methionine was sufficient to release the intracellularly expressed recombinant protein, nodavirus capsid protein, with up to 60% efficiency, compared to lysis by glass bead breakage. These mutant strains also showed approximately three-fold-enhanced secretion of a recombinant extracellular glycoprotein, Saccharomycopsis fibuligera β-glucosidase, with markedly reduced hypermannosylation, particularly in the PMET3-OCH1 mutants. Furthermore, a substantial increase of extracellular glutathione production, up to four-fold, was achieved with the conditional mutant yeast cells. Together, our data support that the conditional cell wall lysis mutants constructed based on the modulation of ScOCH1 and ScCHS3 expression would likely be useful hosts for the improved recovery of proteins and metabolites with industrial application.
α-1, conditional mutant, Saccharomyces cerevisiae, 6-mannosyltransferase, chitin synthase III, MET3 promoter
NCBI PubMed ID: 30706115This review discusses the wealth of information available for the N. crassa cell wall. The basic organization and structure of the cell wall is presented and how the wall changes during the N. crassa life cycle is discussed. Over forty cell wall glycoproteins have been identified by proteomic analyses. Genetic and biochemical studies have identified many of the key enzymes needed for cell wall biogenesis, and the roles these enzymes play in cell wall biogenesis are discussed. The review includes a discussion of how the major cell wall components (chitin, β-1,3-glucan, mixed β-1,3-/β-1,4- glucans, glycoproteins, and melanin) are synthesized and incorporated into the cell wall. We present a four-step model for how cell wall glycoproteins are covalently incorporated into the cell wall. In N. crassa, the covalent incorporation of cell wall glycoproteins into the wall occurs through a glycosidic linkage between lichenin (a mixed β-1,3-/β-1,4- glucan) and a "processed" galactomannan that has been attached to the glycoprotein N-linked oligosaccharides. The first step is the addition of the galactomannan to the N-linked oligosaccharide. Mutants affected in galactomannan formation are unable to incorporate glycoproteins into their cell walls. The second step is carried out by the enzymes from the GH76 family of α-1,6-mannanases, which cleave the galactomannan to generate a processed galactomannan. The model suggests that the third and fourth steps are carried out by members of the GH72 family of glucanosyltransferases. In the third step the glucanosyltransferases cleave lichenin and generate enzyme/substrate intermediates in which the lichenin is covalently attached to the active site of the glucanosyltransferases. In the final step, the glucanosyltransferases attach the lichenin onto the processed galactomannans, which creates new glycosidic bonds and effectively incorporates the glycoproteins into the cross-linked cell wall glucan/chitin matrix.
cell wall, Galactomannan, glucan, filamentous fungi, melanin, Neurospora, glucanosyltransferase, mannanase
NCBI PubMed ID: 31649638Invasive fungal infections are some of the most life-threatening infectious diseases in the hospital setting. In industrialized countries, the most common fungal species isolated from immunocompromised patients are Candida and Aspergillus spp. However, the number of infections due to Mucorales spp. is constantly increasing and little is known about the virulence factors of these fungi. The fungal cell wall is an important structure protecting fungi from the environment. A better knowledge of its composition should improve our understanding of host-pathogen interactions. Cell wall molecules are involved in tissue adherence, immune escape strategies, and stimulation of host defenses including phagocytosis and mediators of humoral immunity. The fungal cell wall is also a target of choice for the development of diagnostic or therapeutic tools. The present review discusses our current knowledge on the cell wall structure of Mucorales in terms of the polysaccharides and glyco-enzymes involved in its biosynthesis and degradation, with an emphasis on the missing gaps in our knowledge.
cell wall, polysaccharides, glucuronic acid, Mucorales, glyco-enzymes
NCBI PubMed ID: 30941108Chitin, chitosan and their complexes with β-glucan (chitin–glucan complex, CGC, and chitosan–glucan complex, ChGC) are value-added polysaccharides extracted from the cell-walls of many fungi. Commercial chitin and its deacetylated form, chitosan, are currently obtained from marine waste material, mostly animal sources (crustaceans and marine invertebrates), through harsh chemical procedures that have low reproducibility due to the variability of the composition of the sources and their seasonal character. These disadvantages are overcome by using fungi as sources of chitinous polymers. The extraction of chitin/chitosan from fungi cell-walls has the great advantage of yielding products with stable composition and properties, using simpler procedures, with the added benefit of also generating CGC and ChGC, two copolymers that combine the proven properties of chitin/chitosan with those of β-glucans. Over the last decades, fungal chitinous polymers have been the focus of extensive research that included optimization of the cultivation conditions of a wide range of species and the development of optimized extraction, purification and characterization techniques, as well as the demonstration of the biopolymers' biological properties, which include immunomodulatory, anticancer, antioxidant and antimicrobial activity. Given these properties, several attempts were made to develop applications for them in areas ranging from biomedicine and pharmaceuticals to food and agriculture. Despite their wide range of proven functional properties that include the ability to form different polymeric structures, as well as biological activity, fungal chitinous biopolymers are still underexplored. Nevertheless, these biopolymers hold great potential for development into valuable products or applications that are surely worth further investigation.
fungi, chitosan, chitin, cell-wall polysaccharides, chitin–glucan complex (CGC), chitosan–glucan complex (ChGC)
Publication DOI: 10.1002/jctb.6325Chitin is a unique structural exopolysaccharide abundantly found in nature. This exopolysaccharide has a unique chemical structure that acts as a protective outermost covering for most of the crustaceans in aquatic ecosystem. This fortification is because of the insoluble nature of this exopolysaccharide which consist of a linear chain of β-(1→4)-linked-N-acetylglucosamine units. Chitin is hydrolyzed with the help of a hydrolase known as chitinase. Variety of microbial species have been explored for chitinase production. Chitinolytic microbial species can be alternatively used for degradation of chitin instead of chemical treatment in agricultural sector. This biological approach has lesser environmental impact because of its apparently safe nature. In the current study, bioprospecting of chitinase producing species was conducted and different chitinolytic bacterial strains were screened for chitinase production which could have anti-fungal potential. Bacterial isolates were identified based on polyphasic approach and the enzyme production was optimized using one-variable-at-a-time technique. Hyphal extension method was used for determination of anti-fungal potential of chitinase.Glutamicibacter uratoxydans was indigenously isolated and identified for chitinase production. G. uratoxydans is a novel bacterial species which has not been previously explored to produce chitinase or other hydrolases. G. uratoxydans biosynthesized chitinase utilizing colloidal chitin as a sole source of carbon. The chitinase biosynthesized by G. uratoxydans is effectively potent against Aspergillus fumigatus thus, suggesting that this extracellular enzyme could be used for the treatment of fungal infection caused by filamentous fungi.
cell wall, antifungal activity, chitin, chitinase, Glutamicibacter uratoxydans
Publication DOI: 10.1007/s12649-019-00746-2Chitin and chitosan are two related polysaccharides that provide important structural stability to fungal cell walls. Often embedded deeply within the cell wall structure, these molecules anchor other components at the cell surface. Chitin-directed organization of the cell wall layers allows the fungal cell to effectively monitor and interact with the external environment. For fungal pathogens, this interaction includes maintaining cellular strategies to avoid excessive detection by the host innate immune system. In turn, mammalian and plant hosts have developed their own strategies to process fungal chitin, resulting in chitin fragments of varying molecular size. The size-dependent differences in the immune activation behaviors of variably sized chitin molecules help to explain how chitin and related chitooligomers can both inhibit and activate host immunity. Moreover, chitin and chitosan have recently been exploited for many biomedical applications, including targeted drug delivery and vaccine development.
NCBI PubMed ID: 31807896The fungal cell wall serves as the interface between the cell and the environment. Fungal cell walls are composed largely of polysaccharides, primarily glucans and chitin, though in many fungi stress-resistant cell types elaborate additional cell wall structures. Here, we use solid-state nuclear magnetic resonance spectroscopy to compare the architecture of cell wall fractions isolated from Saccharomyces cerevisiae spores and Cryptococcus neoformans melanized cells. The specialized cell walls of these two divergent fungi are highly similar in composition. Both use chitosan, the deacetylated derivative of chitin, as a scaffold on which a polyaromatic polymer, dityrosine and melanin, respectively, is assembled. Additionally, we demonstrate that a previously identified but uncharacterized component of the S. cerevisiae spore wall is composed of triglycerides, which are also present in the C. neoformans melanized cell wall. Moreover, we identify a tyrosine-derived constituent in the C. neoformans wall that, although it is not dityrosine, is a non-pigment constituent of the cell wall. The similar composition of the walls of these two phylogenetically distant species suggests that triglycerides, polyaromatics, and chitosan are basic building blocks used to assemble highly stress-resistant cell walls and the use of these constituents may be broadly conserved in other fungal species.
chitosan, Saccharomyces cerevisiae, chitin, fungal cell wall, solid-state NMR, Cryptococcus neoformans, melanin, macromolecular assembly, dityrosine, triglycerides
NCBI PubMed ID: 33271921Cryptococcus neoformans and Cryptococcus gattii are two species complexes in the large fungal genus Cryptococcus and are responsible for potentially lethal disseminated infections. These two complexes share several phenotypic traits, such as production of the protective compound melanin. In C. neoformans, the pigment associates with key cellular constituents that are essential for melanin deposition within the cell wall. Consequently, melanization is modulated by changes in cell-wall composition or ultrastructure. However, whether similar factors influence melanization in C. gattii is unknown. Herein, we used transmission EM, biochemical assays, and solid-state NMR spectroscopy of representative isolates and "leaky melanin" mutant strains from each species complex to examine the compositional and structural factors governing cell-wall pigment deposition in C. neoformans and C. gattii. The principal findings were the following. 1) C. gattii R265 had an exceptionally high chitosan content compared with C. neoformans H99; a rich chitosan composition promoted homogeneous melanin distribution throughout the cell wall but did not increase the propensity of pigment deposition. 2) Strains from both species manifesting the leaky melanin phenotype had reduced chitosan content, which was compensated for by the production of lipids and other nonpolysaccharide constituents that depended on the species or mutation. 3) Changes in the relative rigidity of cell-wall chitin were associated with aberrant pigment retention, implicating cell-wall flexibility as an independent variable in cryptococcal melanin assembly. Overall, our results indicate that cell-wall composition and molecular architecture are critical factors for the anchoring and arrangement of melanin pigments in both C. neoformans and C. gattii species complexes.
Molecular Structure, cell wall, polysaccharides, virulence factor, opportunistic pathogen, nuclear magnetic resonance (NMR), fungi, Cryptococcus, solid-state NMR, melanin
NCBI PubMed ID: 31896575The human gut microbiota has been revealed in recent years as a factor that plays a decisive role in the maintenance of human health, as well as in the development of many non-communicable diseases. This microbiota can be modulated by various dietary factors, among which complex carbohydrates have a great influence. Although most complex carbohydrates included in the human diet come from vegetables, there are also options to include complex carbohydrates from non-vegetable sources, such as chitin and its derivatives. Chitin, and its derivatives such as chitosan can be obtained from non-vegetable sources, the best being insects, crustacean exoskeletons and fungi. The present review offers a broad perspective of the current knowledge surrounding the impacts of chitin and its derived polysaccharides on the human gut microbiota and the profound need for more in-depth investigations into this topic. Overall, the effects of whole insects or meal on the gut microbiota have contradictory results, possibly due to their high protein content. Better results are obtained for the case of chitin derivatives, regarding both metabolic effects and effects on the gut microbiota composition.
polysaccharides, insect, gut microbiota, prebiotic, chitosan, chitin, crustacean
NCBI PubMed ID: 32545663Two chitosan extracts were prepared by chemical and enzymatic treatment of Ganoderma lucidum mushroom, as an alternative source to crustacean shells. The molecular weight of the enzymatic extract was lower than that of the chemical one and of shrimp chitosan, as determined by viscosity measurements. Characteristic signals were identified in the 1 H-NMR spectra and high deacetylation degree indicated good physico-chemical properties for both mushroom chitosan extracts. The scavenging capacity of mushroom chitosan extracts was moderate against the synthetic radicals of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH), but higher values were observed for the enzymatic extract, compared to the chemical extract and shrimp chitosan. In vitro cytotoxicity was evaluated in L929 mouse fibroblast cell lines and the results of MTT assay showed good cytocompatibility in the tested range of concentrations. The growth of Gram-positive bacteria was inhibited more than Gram-negative bacteria in the presence of mushroom chitosan extracts, in particular by the chemical one, indicating their efficiency as antimicrobial agents. All these results strengthen the evidence of mushroom polysaccharide preparations availability for biomedical applications.
extraction, deacetylation, fungi, radical scavenging activity, α-amylase
NCBI PubMed ID: 32333466To develop more ecologically sustainable agricultural practices requires that we reduce our reliance on synthetic chemical pesticides for crop protection. This will likely involve optimized biocontrol approaches - the use of beneficial soil microbes to attack potential plant pathogens to protect plants from diseases. Many bacterial species, including strains of Bacillus subtilis, have been explored for their biocontrol properties, as they can control the growth of harmful fungi, often by disrupting the fungal cell wall. A strain that is not often considered for this particular application is Bacillus subtilis natto, primarily known for fermenting soybeans via cell wall degradation in the Japanese probiotic dish "natto." Because deconstruction of the fungal cell wall is considered an important biocontrol trait, we were motivated to explore the possible anti-fungal properties of the B. subtilis natto strain. We show that B. subtilis natto can use complex fungal material as a carbon source for growth, and can effectively deconstruct fungal cell walls. We found degradation of fungal cell wall proteins, and showed that growth on a mix of peptides was very strong. We also found that intact fungal cell walls can induce the secretion of chitinases and proteases. Surprisingly, we could show that chitin, the bulk component of the fungal cell wall, does not permit successful growth of the natto strain or induce the secretion of chitinolytic enzymes, although these were produced during exposure to proteins or to complex fungal material. We have further shown that protease secretion is likely a constitutively enabled mechanism for nutrient scavenging by B. subtilis natto, as well as a potent tool for the degradation of fungal cell walls. Overall, our data highlight B. subtilis natto as a promising candidate for biocontrol products, with relevant behaviors that can be optimized by altering growth conditions. Whereas it is common for bacterial biocontrol products to be supplied with chitin or chitosan as a priming polysaccharide, our data indicate that this is not a useful approach with this particular bacterium, which should instead be supplied with either glucose or attenuated fungal material.
protease, secretome, fungal cell wall, chitinase, biocontrol, Bacillus subtilis natto
NCBI PubMed ID: 32296406Vast efforts have been devoted to the development of antifungal drugs targeting the cell wall, but the supramolecular architecture of this carbohydrate-rich composite remains insufficiently understood. Here we compare the cell wall structure of a fungal pathogen Aspergillus fumigatus and four mutants depleted of major structural polysaccharides. High-resolution solid-state NMR spectroscopy of intact cells reveals a rigid core formed by chitin, β-1,3-glucan, and α-1,3-glucan, with galactosaminogalactan and galactomannan present in the mobile phase. Gene deletion reshuffles the composition and spatial organization of polysaccharides, with significant changes in their dynamics and water accessibility. The distribution of α-1,3-glucan in chemically isolated and dynamically distinct domains supports its functional diversity. Identification of valines in the alkali-insoluble carbohydrate core suggests a putative function in stabilizing macromolecular complexes. We propose a revised model of cell wall architecture which will improve our understanding of the structural response of fungal pathogens to stresses.
polysaccharides, Aspergillus fumigatus, chitin, fungal cell wall, solid-state NMR
NCBI PubMed ID: 34732740Background: During the last three decades systemic fungal infections associated to immunosuppressive therapies have become a serious healthcare problem. Clinical development of new antifungals is an urgent requirement. Since fungal but not mammalian cells are encased in a carbohydrate-containing cell wall, which is required for the growth and viability of fungi, the inhibition of cell wall synthesizing machinery, such as β(1,3)-D-glucan synthases (GS) and chitin synthases (CS) that catalyze the synthesis of β(1-3)-D-glucan and chitin, respectively, represent an ideal mode of action of antifungal agents. Although the echinocandins anidulafungin, caspofungin and micafungin are clinically well-established GS inhibitors for the treatment of invasive fungal infections, much effort must still be made to identify inhibitors of other enzymes and processes involved in the synthesis of the fungal cell wall. Purpose: Since natural products (NPs) have been the source of several antifungals in clinical use and also have provided important scaffolds for the development of semisynthetic analogues, this review was devoted to investigate the advances made to date in the discovery of NPs from plants that showed capacity of inhibiting cell wall synthesis targets. The chemical characterization, specific target, discovery process, along with the stage of development are provided here. Methods: An extensive systematic search for NPs against the cell wall was performed considering all the articles published until the end of 2020 through the following scientific databases: NCBI PubMed, Scopus and Google Scholar and using the combination of the terms 'natural antifungals' and 'plant extracts' with 'fungal cell wall'. Results: The first part of this review introduces the state of the art of the structure and biosynthesis of the fungal cell wall and considers exclusively those naturally produced GS antifungals that have given rise to both existing semisynthetic approved drugs and those derivatives currently in clinical trials. According to their chemical structure, natural GS inhibitors can be classified as 1) cyclic lipopeptides, 2) glycolipids and 3) acidic terpenoids. We also included nikkomycins and polyoxins, NPs that inhibit the CS, which have traditionally been considered good candidates for antifungal drug development but have finally been discarded after enduring unsuccessful clinical trials. Finally, the review focuses in the most recent findings about the growing field of plant-derived molecules and extracts that exhibit activity against the fungal cell wall. Thus, this search yielded sixteen articles, nine of which deal with pure compounds and seven with plant extracts or fractions with proven activity against the fungal cell wall. Regarding the mechanism of action, seven (44%) produced GS inhibition while five (31%) inhibited CS. Some of them (56%) interfered with other components of the cell wall. Most of the analyzed articles refer to tests carried out in vitro and therefore are in early stages of development. Conclusion: This report delivers an overview about both existing natural antifungals targeting GS and CS activities and their mechanisms of action. It also presents recent discoveries on natural products that may be used as starting points for the development of potential selective and non-toxic antifungal drugs.
Plant Extracts, chitin, fungal cell wall, antifungal drugs, bioactive natural products, cell wall synthases, systemic fungal infection
NCBI PubMed ID: 33958276Extracellular matrixes (ECMs), such as the cell walls and biofilms, are important for supporting cell integrity and function and regulating intercellular communication. These biomaterials are also of significant interest to the production of biofuels and the development of antimicrobial treatment. Solid-state nuclear magnetic resonance (ssNMR) and magic-angle spinning-dynamic nuclear polarization (MAS-DNP) are uniquely powerful for understanding the conformational structure, dynamical characteristics, and supramolecular assemblies of carbohydrates and other biomolecules in ECMs. This review highlights the recent high-resolution investigations of intact ECMs and native cells in many organisms spanning across plants, bacteria, fungi, and algae. We spotlight the structural principles identified in ECMs, discuss the current technical limitation and underexplored biochemical topics, and point out the promising opportunities enabled by the recent advances of the rapidly evolving ssNMR technology.
bacteria, algae, Plants, fungi, ssNMR
NCBI PubMed ID: 34878762Halophilic fungi thrive in hypersaline habitats and face a range of extreme conditions. These fungal species have gained considerable attention due to their potential applications in harsh industrial processes, such as bioremediation and fermentation under unfavorable conditions of hypersalinity, low water activity, and extreme pH. However, the role of the cell wall in surviving these environmental conditions remains unclear. Here we employ solid-state NMR spectroscopy to compare the cell wall architecture of Aspergillus sydowii across salinity gradients. Analyses of intact cells reveal that A. sydowii cell walls contain a rigid core comprising chitin, β-glucan, and chitosan, shielded by a surface shell composed of galactomannan and galactosaminogalactan. When exposed to hypersaline conditions, A. sydowii enhances chitin biosynthesis and incorporates α-glucan to create thick, stiff, and hydrophobic cell walls. Such structural rearrangements enable the fungus to adapt to both hypersaline and salt-deprived conditions, providing a robust mechanism for withstanding external stress. These molecular principles can aid in the optimization of halophilic strains for biotechnology applications.
cell wall, solid-state NMR, Aspergillus sydowii, halophilic fungi
NCBI PubMed ID: 37925437Solid-state NMR (ssNMR) spectroscopy facilitates the non-destructive characterization of structurally heterogeneous biomolecules in their native setting, for example, comprising proteins, lipids and polysaccharides. Here we demonstrate the utility of high and ultra-high field 1 H-detected fast MAS ssNMR spectroscopy, which exhibits increased sensitivity and spectral resolution, to further elucidate the atomic-level composition and structural arrangement of the cell wall of Schizophyllum commune, a mushroom-forming fungus from the Basidiomycota phylum. These advancements allowed us to reveal that Cu(II) ions and the antifungal peptide Cathelicidin-2 mainly bind to cell wall proteins at low concentrations while glucans are targeted at high metal ion concentrations. In addition, our data suggest the presence of polysaccharides containing N-acetyl galactosamine (GalNAc) and proteins, including the hydrophobin proteins SC3, shedding more light on the molecular make-up of cells wall as well as the positioning of the polypeptide layer. Obtaining such information may be of critical relevance for future research into fungi in material science and biomedical contexts.
NMR, NMR spectroscopy, cell wall, peptide, Schizophyllum commune, proton detection
NCBI PubMed ID: 36181715Pleurotus ostreatus, also known as the oyster mushroom, is a popular edible mushroom cultivated worldwide. This review aims to survey recent progress in the molecular genetics of this fungus and demonstrate its potential as a model mushroom for future research. The development of modern molecular genetic techniques and genome sequencing technologies has resulted in breakthroughs in mushroom science. With efficient transformation protocols and multiple selection markers, a powerful toolbox, including techniques such as gene knockout and genome editing, has been developed, and numerous new findings are accumulating in P. ostreatus. These include molecular mechanisms of wood component degradation, sexual development, protein secretion systems, and cell wall structure. Furthermore, these techniques enable the identification of new horizons in enzymology, biochemistry, cell biology, and material science through protein engineering, fluorescence microscopy, and molecular breeding
cell wall, genome editing, agaricomycete, breeding, mycelial materials, wood degradation
NCBI PubMed ID: 38372792Integral and membrane-associated proteins extracted from neuron-enriched perirhopalial tissue of the jellyfish Cyanea capillata were probed with a panel of lectins that recognize sugar epitopes of varying complexity. Of the 13 lectins tested, only concanavalin A, jacalin lectin and tomato lectin stained distinct bands on Western blots, indicating the presence of repeating α-1,6-mannoses, terminal Gal-α-1,6-GalNAc and repeating β-1,4-linked GlcNAc, respectively. In whole-mounted perirhopalial tissue, jacalin lectin stained several cell types, including neurons, muscle, cilia and mucus strands. Tomato lectin stained secretory cells intensely, and neurons in a punctate fashion. Concanavalin A stained cytoplasmic epitopes in both ecto-and endodermal cells, and ectodermal secretory cells and the mucus strands emanating from them. With the exception of tomato lectin's sugar epitope, the other sugar epitopes identified in this study are “non-complex.” This study suggests that while glycosylation of integral and membrane-associated proteins occurs in Cyanea, the sugars post-translationally linked to these proteins tend to be simple.
carbohydrate, linkage, sugar, Scyphozoa, nerve, Cyanea capillata (Cnidaria)
Publication DOI: 10.1007/BF00318487| New query | Export IDs | Home | Help |
Execution: <1 sec