Effective Deacetylation of Chitin under Conditions of 15 psi/121 °C

No, Hong Kyoon; Cho, Young In; Kim, Hyeung Rak; Meyers, Samuel P.

doi:10.1021/jf990842l

Cited by 62 publications

(33 citation statements)

References 7 publications

(10 reference statements)

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“…The alternative was treatment of the cell walls with concentrated (50%) sodium hydroxide at high temperature. Although usually this treatment is carried out for many hours, No et al (15) found that 20 to 30 min is sufficient if the reaction is carried out in the autoclave. This was the chosen treatment (see Materials and Methods).…”

Section: Resultsmentioning

confidence: 99%

Two Novel Techniques for Determination of Polysaccharide Cross-Links Show that Crh1p and Crh2p Attach Chitin to both β(1-6)- and β(1-3)Glucan in the Saccharomyces cerevisiae Cell Wall

Cabib

2009

Eukaryot Cell

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Previous work, using solubilization of yeast cell walls by carboxymethylation, before or after digestion with ␤(1-3)-or ␤(1-6)glucanase, followed by size chromatography, showed that the transglycosylases Crh1p and Crh2p/Utr2p were redundantly required for the attachment of chitin to ␤(1-6)glucan. With this technique, crh1⌬ crh2⌬ mutants still appeared to contain a substantial percentage of chitin linked to ␤(1-3)glucan. Two novel procedures have now been developed for the analysis of polysaccharide cross-links in the cell wall. One is based on the affinity of curdlan, a ␤(1-3)glucan, for ␤(1-3)glucan chains in carboxymethylated cell walls. The other consists of in situ deacetylation of cell wall chitin, generating chitosan, which can be extracted with acetic acid, either directly (free chitosan) or after digestion with different glucanases (bound chitosan). Both methodologies indicated that all of the chitin in crh1⌬ crh2⌬ strains is free. Reexamination of the previously used procedure revealed that the ␤(1-3)glucanase preparation used (zymolyase) is contaminated with a small amount of endochitinase, which caused erroneous results with the double mutant. After removing the chitinase from the zymolyase, all three procedures gave coincident results. Therefore, Crh1p and Crh2p catalyze the transfer of chitin to both ␤(1-3)-and ␤(1-6)glucan, and the biosynthetic mechanism for all chitin cross-links in the cell wall has been established.The fungal cell wall protects the cell against internal turgor pressure and external mechanical injury. To fulfill these functions, it must be endowed with a resilient structure. Presumably, the cell wall strength is largely due to the cross-links that bind together its components, mainly polysaccharides, giving rise to a tightly knit mesh (6,(11)(12)(13). Interestingly, the crosslinks must be created outside the plasma membrane, because most of the polysaccharides are extruded as they are synthesized at the membrane; therefore, they do not exist inside the cell. This posits a thermodynamic problem, because there are no obvious sources of energy in the periplasmic space. About 20 years ago we proposed that the free energy may come from existing bonds in the polysaccharide chains and that the new cross-links may be originated by transglycosylation, thus creating a new linkage for each one that is broken (5).Ascertaining the mechanism of cross-link formation seemed a worthwhile endeavor, both because of the theoretical implications and because the cell wall is a proven target for antifungal compounds; therefore, more knowledge about its synthesis can be of practical interest. For this type of investigation to proceed, it was necessary to devise some method for the quantitative analysis of cell wall cross-links. We developed such a procedure for the evaluation of the proportion of cell wall chitin that is free or bound to ␤(1-3)-or ␤(1-6)glucan (4). In this methodology, chitin was specifically labeled in vivo with [ 14 C]glucosamine; cell walls were isolated, and their proteins were elim...

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Section: Resultsmentioning

confidence: 99%

Two Novel Techniques for Determination of Polysaccharide Cross-Links Show that Crh1p and Crh2p Attach Chitin to both β(1-6)- and β(1-3)Glucan in the Saccharomyces cerevisiae Cell Wall

Cabib

2009

Eukaryot Cell

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“…Because there was no obvious degradation in the microstructure at the mandible edge, presumably, the treatment did not extract structural elements. Cuticle is comprised of chitin chains and surrounding proteins; however, a harsher protocol (5% NaOH at 100°C) than that used would be needed to remove those proteins attached directly to the chitin fibres (Vincent and Wegst 2004) or cause chitin to undergo significant deacetylation (45% NaOH for 30 min at 15 psi and 121°C; No et al 2000). It is, therefore, likely that proteins were principally affected.…”

Section: Discussionmentioning

confidence: 99%

Unique zinc mass in mandibles separates drywood termites from other groups of termites

Cribb

Stewart

Huang

et al. 2008

Naturwissenschaften

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Previously, the presence of metals in arthropod mandibles has been linked with harder cuticle, and in termites, a 20% increase in hardness has been found for mandibles containing major quantities of zinc. The current study utilises electron microscopy and energy-dispersive X-ray microanalysis to assess incidence and abundance of metals in all extant subfamilies of the Isoptera. The basal clades contain no zinc and little to no manganese in the cutting edge of the mandible cuticle, suggesting that these states are ancestral for termites. However, experimentation with mandibles in vitro indicates the presence of some elements of the cuticular biochemistry necessary to enable uptake of zinc. The Termopsidae, Serritermitidae, Rhinotermitidae and Termitidae all contain minor quantities of manganese, while trace to minor quantities of zinc occur in all except the Serritermitidae. In contrast, all Kalotermitidae or drywood termites contain major levels of zinc in the mandible edge. Diet and life type are explored as links to metal profiles across the termites. The presence of harder mandibles in the drywood termites may be related to lack of access to free water with which to moisten wood. Scratch tests were applied to a set of mandibles. The coefficient of friction for Cryptotermes primus (Kalotermitidae) mandibles, when compared with species from other subfamilies, indicates that zinc-containing mandibles are likely to be more scratch resistant.

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“…Graft copolymerization of vinyl monomers onto chitosan using free radical initiation has attracted the interest of many scientists in the last two decades [109]. Grafting with hydroxyethylmethacrylate (MMA) using azobisisobutironitrile (AIBN) [110], methyl methacrylate using Fenton's reagent as redox initiator [111], dimethylamino ethyl methacrylate and N,N-dimethyl-Nmethacryloxyethyl-N-(3-sulfopropyl)ammonium using ceric(IV)salt as redox initiator [112][113], and N-isopropylacrylamide by y-irradiation method [114] have been reported in the literature.…”

Section: Graft C O P O L Y M E R I Z a T I O Nmentioning

confidence: 99%

Chitosan: The Most Valuable Derivative of Chitin

Nayak¹

2011

Biopolymers

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Effective Deacetylation of Chitin under Conditions of 15 psi/121 °C

Cited by 62 publications

References 7 publications

Two Novel Techniques for Determination of Polysaccharide Cross-Links Show that Crh1p and Crh2p Attach Chitin to both β(1-6)- and β(1-3)Glucan in the Saccharomyces cerevisiae Cell Wall

Two Novel Techniques for Determination of Polysaccharide Cross-Links Show that Crh1p and Crh2p Attach Chitin to both β(1-6)- and β(1-3)Glucan in the Saccharomyces cerevisiae Cell Wall

Unique zinc mass in mandibles separates drywood termites from other groups of termites

Chitosan: The Most Valuable Derivative of Chitin

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