Notes

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

Since the expression of chitinases, chitrotriosidase and chitinase-like proteins is greatly amplified during many infections and diseases, the common feature of chitinase-like proteins and chitinase activity in all organisms appears to be the biochemical defense of the host. Unfortunately, conceptual and methodological errors are present in certain of mammalian chitinase and/or chitotriosidase secretion, accompanied by inactive chitinase-like proteins, as an ancestral defensive means against invasion, fact that the mammalian organism recognizes more promptly the secreted water soluble chitinase produced by a pathogen, rather than the insoluble and well reports and investigations on chitin as an allergen, without mentioning the the importance of the chemical/biochemical characteristics of the isolated chitin or chitosan for the replication of experiments and optimization of knowledge today on the use of chitosans as biomaterials, and more specifically as drug carriers for a variety of applications: the delivery routes being the same as those adopted for the immunological studies. Said Seebio Light-Induced Acid Source , that devote attention to the safety and biocompatibility aspects, never reported intolerance or allergy in individuals and animals, even when the quantities of chitosan used in single experiments were quite large. Therefore, it is concluded that crab, shrimp, prawn and lobster chitins, as well as chitosans of all grades, once purified, should not be considered as "crustacean derivatives", because the isolation procedures have removed proteins, fats and other contaminants to such an extent as to allow them to be classified as chemicals regardless of their 10002/1521-3773(20001103)39:21<3915::AID-ANIE3915>3.CO;2-O2, 91054 Erlangen (Germany) Fax: (+49) 9131-85-26864.Photomodulating Gene Expression by Using Caged siRNAs with Single-Aptamer Caged siRNAs incorporating terminal modification were rationally designed for photochemical regulation of gene silencing induced by RNA interference (RNAi). Through the conjugation of a single oligonucleotide aptamer at the 5' terminus of the antisense RNA strand, enhancement of the blocking effect for RNA-induced silencing complex (RISC) formation/processing was expected, due both/either to the aptamers themselves and/or to their interaction with large binding proteins.

Two oligonucleotide aptamers (AS1411 and MUC-1) were chosen for aptamer-siRNA conjugation through a photolabile linker. This caging strategy was successfully used to photoregulate gene expression both of firefly luciferase and of green fluorescent protein (GFP) in cells. Further patterning experiments revealed that spatial regulation of GFP expression was successfully achieved by using the aptamer-modified caged siRNA and light activation. We expect that further optimized caged siRNAs featuring aptamer conjugation will be promising for practical applications to spatiotemporal photoregulation of gene expression in © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.Oxygenated Aromatic Compounds are Important Precursors of Secondary Organic Colorado, Boulder 80309, Colorado, United States.Technology, Boston 02139, Massachusetts, United States.

Environmental Sciences, University of Colorado Boulder, Boulder 80309, Colorado, Berkeley, Berkeley 94720-3114, California, United States.Pasadena 91125, California, United States.
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