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Jonas O Wolff, Michael Seiter, Stanislav N Gorb
The cuticle of arthropods is usually composed of layers of a chitin-protein-microcomposite, a proteinacous epicuticle and a thin lipid coating. However, in some instances a thick cement layer (cerotegument) covers the cuticle and may produce elaborate microstructures. This has previously been described for millipedes and mites. Here we report the previously unknown presence of a superhydrophobic cerotegument in whip-spiders (Ambypygi) and reveal its variation in ultrastructure and water-repellence between species...
October 14, 2016: Arthropod Structure & Development
Farkhanda Manzoor, Mahnoor Pervez
Baiting systems have been introduced using slow-acting bait toxicants to provide environment-friendly and target-specific termite management. In the present study, the Exterra termite bait system (USA) with chlorfluazuron, a chitin synthesis inhibitor, as the active ingredient was tested against termite colonies. Ten residential areas of Lahore, infested with subterranean termites were selected for the study. The study period was from 2013 to 2015. In-ground stations were installed at 10 sites and above-ground stations were only installed at four test sites...
October 15, 2016: Journal of Economic Entomology
Laura Vannini, Judith H Willis
Previous work with EM immunolocalization examined the intracuticular placement of several antibodies directed against cuticular proteins (CPs) in various structures of Anopheles gambiae. Those structures had long stretches of fairly uniform cuticle. We have now used 19 antibodies directed against members of five CP families on two adult structures with considerable complexity, Johnston's organ and the corneal lens of the compound eye. We also localized chitin with colloidal-gold labeled wheat germ agglutinin...
October 12, 2016: Arthropod Structure & Development
Yojana R Chikate, Vishal V Dawkar, Ranjit S Barbole, Priyadarshini V Tilak, Vidya S Gupta, Ashok P Giri
Helicoverpa armigera is one of the major crop pests and is less amenable to current pest control approaches. RNA interference (RNAi) is emerging as a potent arsenal for the insect pest control over current methods. Here, we examined the effect on growth and development in H. armigera by targeting various enzymes/proteins such as proteases like trypsins (HaTry2, 3, 4 and 6), chymotrypsin (HaChy4) and cysteine protease like cathepsin (HaCATHL); glutathione S-transferases (HaGST1a, 6 and 8); esterases (HaAce4, HaJHE); catalase (HaCAT); super-oxide-dismutase (HaCu/ZnSOD); fatty acid binding protein (HaFabp) and chitin deacetylase (HaCda5b) through dsRNA approach...
October 2016: Pesticide Biochemistry and Physiology
Dámaris Núñez-Gómez, Alcione Aparecida de Almeida Alves, Flavio Rubens Lapolli, María A Lobo-Recio
Mine-impacted water (MIW) is one of the most serious mining problems and has a high negative impact on water resources and aquatic life. The main characteristics of MIW are a low pH (between 2 and 4) and high concentrations of SO4(2-) and metal ions (Cd, Cu, Ni, Pb, Zn, Fe, Al, Cr, Mn, Mg, etc.), many of which are toxic to ecosystems and human life. Shrimp shell was selected as a MIW treatment agent because it is a low-cost metal-sorbent biopolymer with a high chitin content and contains calcium carbonate, an acid-neutralizing agent...
October 9, 2016: Chemosphere
Liang Liu, Rong Wang, Juan Yu, Jie Jiang, Ke Zheng, Lijiang Hu, Zhiguo Wang, Yimin Fan
Partially deacetylated α-chitin nanofibers/nanowhiskers mixtures (DEChNs) and TEMPO-oxidized α-chitin nanowhiskers (TOChNs) that had positive and negative charges, respectively, were transformed into hydrogels with mass concentrations of 0.2, 0.4, 0.6, 0.8 and 1.0% under ammonium hydroxide or hydrochloric acid "gas phase coagulation". To the best of our knowledge, 0.2% is the lowest mass content reported for the successful preparation of physical self-standing hydrogels based on chitin nanofibers/nanowhiskers...
October 12, 2016: Biomacromolecules
Rony Huys, Eduardo Suárez-Morales, María de Lourdes Serrano-Sánchez, Elena Centeno-García, Francisco J Vega
Copepods are aquatic microcrustaceans and represent the most abundant metazoans on Earth, outnumbering insects and nematode worms. Their position of numerical world predominance can be attributed to three principal radiation events, i.e. their major habitat shift into the marine plankton, the colonization of freshwater and semiterrestrial environments, and the evolution of parasitism. Their variety of life strategies has generated an incredible morphological plasticity and disparity in body form and shape that are arguably unrivalled among the Crustacea...
October 12, 2016: Scientific Reports
Zunyong Liu, Xiaoping Zhang, Xin Liu, Chaoyu Fu, Xinyue Han, Yanni Yin, Zhonghua Ma
Fusarium graminearum contains eight chitin synthase (Chs) genes belonging to seven classes. Previous studies have found that deletion of FgChs3b is lethal to F. graminearum, and deletion of FgChs1, FgChs2, FgChs7 and FgChs5 caused diverse defects in chitin content, mycelial growth, conidiation, virulence or stress responses. However, little is known about the functional relationships among these FgChss. In this study, FgChs2 deletion mutant ΔFgChs2 exhibited reduced mycelial growth and virulence as reported previously...
October 11, 2016: Scientific Reports
Maria M Marques, Fausto Queda, Luisa Carvalho, Cátia Santos
Chitin and chitosan are attractive biopolymers with an enormous structural possibility for chemical modification creating the platform for new chemical entities with a broad scope of applications, ranging from material science to medicine. During the last years incredible efforts have been dedicated to the regioselective modification of these biopolymers paving the way to improved properties and tailored activities. Herein the most recent advances on chitin/chitosan regioselective modification, reaction conditions, selectivity and the impact on its applications are highlighted...
October 10, 2016: Chemistry, An Asian Journal
Rebecca C Gregory, Glyn R Hemsworth, Johan P Turkenburg, Samuel J Hart, Paul H Walton, Gideon J Davies
The enzymatic deconstruction of recalcitrant polysaccharide biomass is central to the conversion of these substrates for societal benefit, such as in biofuels. Traditional models for enzyme-catalysed polysaccharide degradation involved the synergistic action of endo-, exo- and processive glycoside hydrolases working in concert to hydrolyse the substrate. More recently this model has been succeeded by one featuring a newly discovered class of mononuclear copper enzymes: lytic polysaccharide monooxygenases (LPMOs; classified as Auxiliary Activity (AA) enzymes in the CAZy classification)...
September 29, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Alireza Chackoshian Khorasani, Seyed Abbas Shojaosadati
Incorporation of nanofibers of chitin (NC), lignocellulose (NLC) and bacterial cellulose (BNC) in pectin was studied to improve prebiotic activity and gastrointestinal resistance of the pectin-nanofibers biocomposites for protection of probiotics under simulated gastrointestinal conditions. The biocomposites were prepared using various compositions of pectin and nanofibers, which were designed using D-optimal mixture method. The incorporation of the nanofibers in pectin led to a slow degradation of the pectin-nanofibers biocomposites in contrast to their rapid swelling...
October 6, 2016: International Journal of Biological Macromolecules
Mi Young Noh, Subbaratnam Muthukrishnan, Karl J Kramer, Yasuyuki Arakane
Adult beetles (Coleoptera) are covered primarily by a hard exoskeleton or cuticle. For example, the beetle elytron is a cuticle-rich highly modified forewing structure that shields the underlying hindwing and dorsal body surface from a variety of harmful environmental factors by acting as an armor plate. The elytron comes in a variety of colors and shapes depending on the coleopteran species. As in many other insect species, the cuticular tanning pathway begins with tyrosine and is responsible for production of a variety of melanin-like and other types of pigments...
October 2016: Current Opinion in Insect Science
M S Fernández, F J I A J L Valenzuela Arias Neira-Carrillo Arias
Biominerals are inorganic-organic hybrid composites formed via self-assembled bottom up processes under mild conditions. Biominerals show interesting physical properties, controlled hierarchical structures and robust remodeling or repair mechanisms. Biological processes associated with biominerals remain to be developed into practical engineering processes. Therefore, the formation of biominerals is inspiring for the design of materials, especially those fabricated at ambient temperatures. The study described herein involves the influence of chicken outer eggshell membrane on the type of calcium carbonate (CaCO3) polymorph deposited on the shell of the land snail Helix aspersa during the repair process after an injury...
October 4, 2016: Journal of Structural Biology
Laura Vannini, Judith H Willis
The largest Arthropod cuticular protein family, CPR, has the Rebers and Riddiford (R&R) Consensus that in an extended form confers chitin-binding properties. Two forms of the Consensus, RR-1 and RR-2, have been recognized and initial data suggested that the RR-1 and RR-2 proteins were present in different regions within the cuticle itself. Thus, RR-2 proteins would contribute to exocuticle that becomes sclerotized, while RR-1s would be found in endocuticle that remains soft. An alternative, and more common, suggestion is that RR-1 proteins are used for soft, flexible cuticles such as intersegmental membranes, while RR-2s are associated with hard cuticle such as sclerites and head capsules...
October 4, 2016: Arthropod Structure & Development
Masahiro Kimura, Satoshi Wakita, Kotarou Ishikawa, Kazutaka Sekine, Satoshi Yoshikawa, Akira Sato, Kazuaki Okawa, Akinori Kashimura, Masayoshi Sakaguchi, Yasusato Sugahara, Daisuke Yamanaka, Naohito Ohno, Peter O Bauer, Fumitaka Oyama
Chitotriosidase (Chit1) is an enzyme associated with various diseases, including Gaucher disease, chronic obstructive pulmonary disease, Alzheimer disease and cystic fibrosis. In this study, we first expressed mouse mature Chit1 fused with V5 and (His)6 tags at the C-terminus (Chit1-V5-His) in the cytoplasm of Escherichia coli and found that most of the expressed protein was insoluble. In contrast, Chit1 tagged with Protein A at the N-terminus and V5-His at the C-terminus, was expressed in the periplasmic space of E...
2016: PloS One
Annegret Wiedemann, Anja Spadinger, Axel Löwe, Allison Seeger, Frank Ebel
Treatment of invasive fungal infections often fails due to the limited number of therapeutic options. In this study, we have analyzed the impact of agents activating the High Osmolarity Glycerol (HOG) pathway on molds that cause infections in humans and livestock. We found that agents like fludioxonil and iprodione, have a clear anti-fungal activity against pathogenic Aspergillus, Lichtheimia, Rhizopus and Scedosporium species. Only A. terreus turned out to be resistant to fludioxonil, even though it is sensitive to iprodione and able to adapt to hyperosmotic conditions...
September 28, 2016: International Journal of Medical Microbiology: IJMM
Jiaul Hoque, Padma Akkapeddi, Chandardhish Ghosh, Divakara S S M Uppu, Jayanta Haldar
Bacterial colonization and subsequent formation of biofilms onto surfaces of medical devices and implants is a major source of nosocomial infections. Most antibacterial coatings to combat infections are either metal-based or non-degradable polymer-based and hence limited by their non-degradability and unpredictable toxicity. Moreover, to combat infections effectively, the coatings are required to display simultaneous antibacterial and antibiofilm activity. Herein we report biocompatible and biodegradable coatings based on organo-soluble quaternary chitin polymers which were immobilized non-covalently onto surfaces as bactericidal paint...
October 6, 2016: ACS Applied Materials & Interfaces
Lukasz F Sobala, Ying Wang, Paul N Adler
No abstract text is available yet for this article.
October 1, 2016: Development
Carlos F C João, Coro Echeverria, Alexandre Velhinho, Jorge C Silva, Maria H Godinho, João P Borges
Inspired by chitin based hierarchical structures observed in arthropods exoskeleton, this work reports the capturing of chitin nanowhiskers' chiral nematic order into a chitosan matrix. For this purpose, highly crystalline chitin nanowhiskers (CTNW) with spindle-like morphology and average aspect ratio of 24.9 were produced by acid hydrolysis of chitin. CTNW were uniformly dispersed at different concentrations in aqueous suspensions. The suspensions liquid crystalline phase domain was determined by rheological measurements and polarized optical microscopy (POM)...
January 2, 2017: Carbohydrate Polymers
Khadijeh Alishah, Sedigheh Asad, Khosro Khajeh, Neda Akbari
Uric acid, a side product of nucleotide metabolism, should be cleared from blood stream since its accumulation can cause cardiovascular diseases and gout. Uricase (urate oxidase) converts uric acid to 5-hydroxyisourate, but it is absent in human and other higher apes. Yet, the recombinant form of uricase, Rasburicase, is now commercially available to cure tumor lysis syndrome by lowering serum uric acid level. Developing new methods to efficiently purify pharmaceutical proteins like uricase has attracted researchers' attention...
November 2016: Enzyme and Microbial Technology
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