keyword
MENU ▼
Read by QxMD icon Read
search

Chitin

keyword
https://www.readbyqxmd.com/read/28736299/n-acetylglucosamine-the-building-block-of-chitin-inhibits-growth-of-neurospora-crassa
#1
Romana Gaderer, Verena Seidl-Seiboth, Ronald P de Vries, Bernhard Seiboth, Lisa Kappel
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...
July 20, 2017: Fungal Genetics and Biology: FG & B
https://www.readbyqxmd.com/read/28735006/chitosan-as-a-bioactive-polymer-processing-properties-and-applications
#2
REVIEW
A Muxika, A Etxabide, J Uranga, P Guerrero, K de la Caba
Chitin is one of the most abundant natural polysaccharides in the world and it is mainly used for the production of chitosan by a deacetylation process. Chitosan is a bioactive polymer with a wide variety of applications due to its functional properties such as antibacterial activity, non-toxicity, ease of modification, and biodegradability. This review summarizes the most common chitosan processing methods and highlights some applications of chitosan in various industrial and biomedical fields. Finally, environmental concerns of chitosan-based films, considering the stages from raw materials extraction up to the end of life after disposal, are also discussed with the aim of finding more eco-friendly alternatives...
July 19, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28732918/hydrophobic-structural-modification-of-chitosan-and-its-impact-on-nanoparticle-synthesis-a-physicochemical-study
#3
B Jothimani, S Sureshkumar, B Venkatachalapathy
Chitin is a naturally occurring fully N-acylated biopolymer which cannot be converted into nanomaterial easily due to its inherent rigidity and chemical inertness. These properties limit the utility of chitin in nanomaterial-based applications. Therefore, our aim in the present work was, to prepare chitin like fully N-acylated derivatives with a hydrophobic moiety and study the impact on nanoparticles synthesis. We report such a fully substituted derivative, N-(Thiophene-2-acetyl)chitosan, its characterization and physicochemical studies of the nanoparticles synthesized...
October 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28732905/preparation-of-fungus-derived-chitin-nanocrystals-and-their-dispersion-stability-evaluation-in-aqueous-media
#4
Ning Lin, Shasha Zhao, Lin Gan, Peter R Chang, Tao Xia, Jin Huang
The chitin nanocrystal is a promising nano-reinforcing agent, but the parasitic pathogens carried on crabs and shrimp shells as main sources limit its application in some fields. In this study, the ChNs which avoided possible safety risks were extracted from mushrooms via protein/mineral-purification and subsequent HCl-hydrolysis. Such fungus-derived ChNs presented an α-chitin crystalline structure with a length of 143±24nm and a diameter of 10±2nm. Since the dispersion stability of ChNs suspension determines their further applications, this present study emphasized the dispersity of ChNs in aqueous media evaluated by the viscosity under steady-shear flow and UV-vis absorption, whose results indicated that ChNs in dispersion would aggregate when the concentration of homogeneous dispersion reached 0...
October 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28732872/chitin-based-heteroatom-doped-porous-carbon-as-electrode-materials-for-supercapacitors
#5
Jie Zhou, Li Bao, Shengji Wu, Wei Yang, Hui Wang
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...
October 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28732869/in-situ-formation-of-supramolecular-aggregates-between-chitin-nanofibers-and-silver-nanoparticles
#6
Ruchira N Wijesena, Nadeeka D Tissera, Charith Abeyratne, Osura M Bangamuwa, Natalie Ludowyke, Damayanthi Dahanayake, Sunanda Gunasekara, Nuwan de Silva, Rohini M de Silva, K M Nalin de Silva
Chitin and chitin derivatives have gained significant research interest over the years due to a number of beneficial properties that can be exploited in various application fields. Particularly, interactions between their nanostructures and other nanomaterials are of great interest. In situ photo-reduction of AgCl in chitin nanofiber aqueous dispersions resulted in significant loss of colloidal stability of both chitin nanofibers (CNF) and silver nanoparticles. UV-vis spectroscopy was used to characterize the extinction profiles of in-situ prepared CNF and several silver nanoparticle mixtures over the reaction steps...
October 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28729276/draft-genome-sequence-of-paenibacillus-sp-strain-my03-a-terrestrial-bacterium-capable-of-degrading-multiple-marine-derived-polysaccharides
#7
Huihui Liu, Yuanyuan Cheng, Jingyan Gu, Yanhui Wang, Junge Li, Fuchuan Li, Wenjun Han
The bacterium Paenibacillus sp. strain MY03, isolated from the root soil of cypress, can effectively degrade marine-derived polysaccharides such as agar, alginate, and chitin. Here, we present the draft genome sequence of MY03. Putative enzymes, including 3 agarases, 1 alginate lyase, and 1 chitinase, were found.
July 20, 2017: Genome Announcements
https://www.readbyqxmd.com/read/28727825/differentially-expressed-genes-in-the-head-of-the-2nd-instar-pre-molting-larvae-of-the-nm2-mutant-of-the-silkworm-bombyx-mori
#8
Pingyang Wang, Simin Bi, Fan Wu, Pingzhen Xu, Xingjia Shen, Qiaoling Zhao
Molting is an important physiological process in the larval stage of Bombyx mori and is controlled by various hormones and peptides. The silkworm mutant that exhibits the phenotype of non-molting in the 2nd instar (nm2) is incapable of molting in the 2nd instar and dies after seven or more days. The ecdysone titer in the nm2 mutant is lower than that in the wildtype, and the mutant can be rescued by feeding with 20E and cholesterol. The results of positional cloning indicated that structural alteration of BmCPG10 is responsible for the phenotype of the nm2 mutant...
2017: PloS One
https://www.readbyqxmd.com/read/28727439/solid-state-nmr-study-of-the-cicada-wing
#9
John David Gullion, Terry Gullion
Wings of flying insects are part of the cuticle which forms the exoskeleton. The primary molecular components of cuticle are protein, chitin, and lipid. How these components interact with one another to form the exoskeleton is not completely understood. The difficulty in characterizing the cuticle arises because it is insoluble and noncrystalline. These properties severely limit the experimental tools that can be used for molecular characterization. Solid-state nuclear magnetic resonance experiments have been used in the past to characterize the exoskeleton of beetles and have found that chitin and protein make comparable contributions to the molecular matrix...
July 20, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28726011/thermal-structural-and-acetylation-behavior-of-snail-and-periwinkle-shells-chitin
#10
Oluwashina Philips Gbenebor, Emmanuel Isaac Akpan, Samson Oluropo Adeosun
This article reports a successful removal of CaCO3 from snail and periwinkle shells for the purpose of producing high quality chitin for possible application as bio-fillers in bone fixation materials. Experiment was designed with varying concentrations of acid and alkali for demineralization, deproteinization and deacetylation of the samples. Thermal characteristics, morphology, degree of de-acetylation, crystalline structure and hydrogen bonding characteristics of the extracted chitin were examined. Infra-red spectra, thermogravimetric analysis and X-ray diffraction patterns show that demineralization with 1...
July 19, 2017: Progress in biomaterials
https://www.readbyqxmd.com/read/28721730/heterologous-expression-and-characterization-of-a-novel-chitinase-chien1-from-coprinopsis-cinerea-and-its-synergism-in-the-degradation-of-chitin
#11
Xin Niu, Jiang-Sheng Zhou, Yan-Xin Wang, Cuicui Liu, Zhonghua Liu, Sheng Yuan
Chitinase ChiEn1 did not hydrolyze insoluble chitin but showed hydrolysis and transglycosylation activities towards 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...
July 19, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28720940/recovery-of-protein-hydrolysate-and-chitosan-from-black-tiger-shrimp-penaeus-monodon-heads-approaching-a-zero-waste-process
#12
Pham Thi Dan Phuong, Nguyen Cong Minh, Hoang Ngoc Cuong, Nguyen Van Minh, Nguyen The Han, Nguyen Van Hoa, Ha Thi Hai Yen, Trang Si Trung
Shrimp heads are considered as a potential source for the recovery of many valuable components such as chitin, protein and carotenoids. In the present study, both protein hydrolysate and chitin/chitosan were recovered using combination of physical, biological and chemical treatments. Shrimp heads were separated from liquid phase by a facile and efficient physical pretreatment. The liquid fraction was then hydrolyzed using formic acid and vacuum concentrated to obtain an astaxanthin-rich protein hydrolysate...
June 2017: Journal of Food Science and Technology
https://www.readbyqxmd.com/read/28719186/elastomer-reinforced-with-regenerated-chitin-from-alkaline-urea-aqueous-system
#13
Peng Yu, Hui He, Yuanfang Luo, Demin Jia, Alain Dufresne
Novel hybrid elastomer/regenerated chitin (R-chitin) composites were developed, for the first time, by introducing chitin solution (dissolved in alkaline/urea aqueous solution at low temperature) into rubber latex, and then co-coagulating using ethanol as the co-coagulant. During the rapid co-precipitation process, the chitin solution showed rapid coagulant-induced gelation and a porous chitin phase was generated, while the rubber latex particles were synchronously demulsificated to form the rubbery phase. The two phases interlaced and interpenetrated simultaneously to form an Interpenetrating Polymer Network (IPN) structure, which was evidenced by SEM observation...
July 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28716752/anticancer-activity-of-silver-and-copper-embedded-chitin-nanocomposites-against-human-breast-cancer-mcf-7-cells
#14
Dhanasekaran Solairaj, Palanivel Rameshthangam, Gnanapragasam Arunachalam
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...
July 14, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28712778/hydrothermal-carbonization-for-the-preparation-of-hydrochars-from-glucose-cellulose-chitin-chitosan-and-wood-chips-via-low-temperature-and-their-characterization
#15
Hamza Simsir, Nurettin Eltugral, Selhan Karagoz
In this work, the hydrothermal carbonization of glucose, cellulose, chitin, chitosan and wood chips at 200°C at processing times between 6 and 48h was studied. The carbonization degree of wood chips, cellulose and chitosan obviously increases as function of time. The heating value of glucose increases to 88% upon carbonization for 48h, while it is only 5% for chitin. It is calculated to be between 44 and 73% for wood chips, chitosan and cellulose. Glucose yielded complete formation of spherical hydrochar structures at a shorter processing time, as low as 12h...
July 6, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28712648/elucidating-biochemical-features-and-biological-roles-of-streptomyces-proteins-recognizing-crystalline-chitin-and-cellulose-types-and-their-soluble-derivatives
#16
Hildgund Schrempf
Pioneering biochemical, immunological, physiological and microscopic studies in combination with gene cloning allowed uncovering previously unknown genes encoding proteins of streptomycetes to target crystalline chitin and cellulose as well as their soluble degradation-compounds via binding protein dependent transporters. Complementary analyses provoked an understanding of novel regulators governing transcription of selected genes. These discoveries induced detecting close and distant homologues of former orphan proteins encoded by genes from different bacteria...
June 20, 2017: Carbohydrate Research
https://www.readbyqxmd.com/read/28711613/enzyme-activity-and-expression-pattern-of-intra-and-extracellular-chitinase-and-%C3%AE-1-3-glucanase-of-wickerhamomyces-anomalus-eg2-using-glycol-chitin-and-glucan-containing-high-polymer-complex
#17
Sin-Hyoung Hong, Yong-Su Song, Dong-Jun Seo, Kil-Yong Kim, Woo-Jin Jung
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...
July 12, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28698589/transglycosylation-by-a-chitinase-from-enterobacter-cloacae-subsp-cloacae-generates-longer-chitin-oligosaccharides
#18
Mohan Krishna Mallakuntla, Papa Rao Vaikuntapu, Bhoopal Bhuvanachandra, Subha Narayan Das, Appa Rao Podile
Humans have exploited natural resources for a variety of applications. Chitin and its derivative chitin oligosaccharides (CHOS) have potential biomedical and agricultural applications. Availability of CHOS with the desired length has been a major limitation in the optimum use of such natural resources. Here, we report a single domain hyper-transglycosylating chitinase, which generates longer CHOS, from Enterobacter cloacae subsp. cloacae 13047 (EcChi1). EcChi1 was optimally active at pH 5.0 and 40 °C with a Km of 15...
July 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28697307/prawn-shell-derived-chitin-nanofiber-membranes-as-advanced-sustainable-separators-for-li-na-ion-batteries
#19
Tianwen Zhang, Bao Shen, Hong-Bin Yao, Tao Ma, Lei-Lei Lu, Fei Zhou, Shu-Hong Yu
Separators, necessary components to isolate cathodes and anodes in Li/Na-ion batteries, are consumed in a large amount per year and thus their sustainability should be concerned for renewable energy storage systems. However, eco-efficient and environmentally friendly fabrication of separators with high mechanical strength, excellent thermal stability and good electrolyte wettability is still challenging. Herein, we reported the fabrication of a new type of separators for Li/Na-ion batteries through the self-assembly of eco-friendly chitin nanofibers derived from prawn shells...
July 11, 2017: Nano Letters
https://www.readbyqxmd.com/read/28691246/formation-and-function-of-the-xestoleberis-spot-in-xestoleberis-hanaii-crustacea-ostracoda
#20
Shinnosuke Yamada
The crescent sculpture of the so-called "Xestoleberis-spot" develops inside the calcified valve of the family Xestoleberididae. Electron microscopic observations on both, intermoult and postmoult stages of Xestoleberis species reveal that the "Xestoleberis-spot" system consists of three elements; two calcified chambers, a vesicle of electron-dense material and an uncalcified procuticle. The formation and function of the "Xestoleberis-spot" system are discussed. In conclusion, the "Xestoleberis-spot" system functions as the muscle attachment site for several antennal muscles, and provides the material for chitinous fibers in the exocuticle of outer lamella...
July 10, 2017: Journal of Morphology
keyword
keyword
59661
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"