Controlling the absorption and emission properties of polyparaphenylenevinylene films

In this work we used the conversion process of a precursor polymer into polyparaphenylenevinylene (PPV) at low temperatures in order to control the effective conjugation degree of spin-casted PPV films. The absorption and emission spectra of the films were studied by following a partial substitution of chloride counterions from poly(xylylidene tetrahydrothiophenium chloride) (PTHT), used as a precursor, by sodium acid dodecyl benzenesulfonate (DBS), added as a surfactant salt. Upon controlling the DBS amount and conversion temperature (T-c) of PTHT/DBS to PPV films, the band gap of PPV changed from 409 to 506 nm, and 505 to 532 nm, values obtained from absorbance and emission measurements, respectively. Based on these experimental data, we proposed a physical model which represents the chemical structure of PPV as a distribution of conjugated chain segments (like oligomers) alternated by non-conjugated segments (structural defects and/or from the precursor polymer). (C) 2008 Elsevier B.V. All rights reserved.

Metabotropic glutamate receptors transduce signals for neurite outgrowth after binding of the prion protein to laminin gamma 1 chain

The prion protein (PrP(C)) is highly expressed in the nervous system, and its abnormal conformer is associated with prion diseases. PrP(C) is anchored to cell membranes by glycosylphosphatidylinositol, and transmembrane proteins are likely required for PrP(C)-mediated intracellular signaling. Binding of laminin (Ln) to PrP(C) modulates neuronal plasticity and memory. We addressed signaling pathways triggered by PrP(C)-Ln interaction in order to identify transmembrane proteins involved in the transduction of PrP(C)-Ln signals. The Ln gamma 1-chain peptide, which contains the Ln binding site for PrP(C), induced neuritogenesis through activation of phospholipase C (PLC), Ca(2+) mobilization from intracellular stores, and protein kinase C and extracellular signal-regulated kinase (ERK1/2) activation in primary cultures of neurons from wild-type, but not PrP(C)-null mice. Phage display, coimmunoprecipitation, and colocalization experiments showed that group I metabotropic glutamate receptors (mGluR1/5) associate with PrP(C). Expression of either mGluR1 or mGluR5 in HEK293 cells reconstituted the signaling pathways mediated by PrP(C)-Ln gamma 1 peptide interaction. Specific inhibitors of these receptors impaired PrP(C)-Ln gamma 1 peptide-induced signaling and neuritogenesis. These data show that group I mGluRs are involved in the transduction of cellular signals triggered by PrP(C)-Ln, and they support the notion that PrP(C) participates in the assembly of multiprotein complexes with physiological functions on neurons.-Beraldo, F. H., Arantes, C. P., Santos, T. G., Machado, C. F., Roffe, M., Hajj, G. N., Lee, K. S., Magalhaes, A. C., Caetano, F. A., Mancini, G. L., Lopes, M. H., Americo, T. A., Magdesian, M. H., Ferguson, S. S. G., Linden, R., Prado, M. A. M., Martins, V. R. Metabotropic glutamate receptors trans-duce signals for neurite outgrowth after binding of the prion protein to laminin gamma 1 chain. FASEB J. 25, 265-279 (2011). www.fasebj.org

Phenol-furfural resins to elaborate composites, reinforced with sisal fibers - Molecular analysis of resin and properties of composites

Resol type resins were prepared in alkaline conditions (potassium hydroxide or potassium carbonate) using furfural obtained by acid hydrolysis of abundant renewable resources from agricultural and forestry waste residues. The structures of the resins were fully determined by H-1, C-13, and 2D NMR spectrometries with the help of four models compounds synthesized specially for this study. MALDI-Tof mass spectrometry experiments indicated that a majority of linear oligomers and a minority of cyclic ones constituted them. Composites were prepared with furfural-phenol resins and sisal fibers. These fibers were chosen mainly because they came from natural lignocellulosic material and they presented excellent mechanical microscopy images indicated that the composites displayed excellent adhesion between resin and fibers. Impact strength measurement showed that mild conditions were more suitable to prepare thermosets. Nevertheless, mild conditions induced a high-diffusion coefficient for water absorption by composites. Composites with good properties could be prepared using high proportion of materials obtained from biomass without formaldehyde. (c) 2008 Wiley Periodicals, Inc.

New insights into the structures of diorganotellurium Oxides. The first polymeric diorganotelluroxane[(p-MeOC6H4)2TEO]n

The characterization of the previously reported diorganotellurium oxides R₂TeO (R = Ph (1) and p-MeOC₆H₄ (2)) was revisited by osmometric molecular weight determinations, ¹²⁵Te NMR spectroscopy, and electrospray spectrometry (ESMS) in solution and by 125Te MAS NMR spectroscopy in the solid state. The single-crystal X-ray structure of 2 revealed a polymeric arrangement that features a zigzag configured Te-O backbone without any secondary Te···O interactions. In solution 1 and 2 exist predominantly as monomers but appear to be in equilibrium with higher oligomers to a minor extent.

Recent advances in chloroplast and mitochondrial division

Stomatin, originally identified as a major protein of the human erythrocyte membrane, is widely expressed in various tissues. Orthologues are found in vertebrates, invertebrates, plants, and microorganisms. Related proteins exhibit a common core structure, termed the prohibitin (PHB) domain, with varying extensions. Stomatin has an unusual topology, similar to caveolin-1, with a hydrophobic domain embedded at the cytoplasmic side of the membrane. Additional anchoring is provided by palmitoylation and the membrane affinity of the PHB domain. Stomatin associates with cholesterol-rich microdomains (lipid rafts), forms oligomers, and thereby displays a scaffolding function by generating large protein-lipid complexes. It regulates the activity of various membrane proteins by reversibly recruiting them to lipid rafts. This mechanism of regulation has been shown for GLUT-1 and may also apply for ion channels. Stomatin is located at the plasma membrane, particularly in microvilli, in endocytic and exocytic vesicles, and cytoplasmic granules. Stomatin-carrying endosomes are highly dynamic and interact with lipid droplets suggesting a role in intracellular lipid transport. This subcellular distribution and the caveolin-like protein structure suggest important membrane organizing functions for stomatin. A general picture emerges now that cell membranes contain cholesterol-rich domains that are generated and regulated by scaffolding proteins like caveolins, stomatins, and flotillin/reggie proteins.

Purification and characterisation of endo-β-1,4-glucanase and laminarinase enzymes from the gecarcinid land crab Gecarcoidea natalis and the aquatic crayfish Cherax destructor

Laminarinase and endo-β-1,4-glucanase were purified and characterised from the midgut gland of the herbivorous land crab Gecarcoidea natalis and the crayfish Cherax destructor. The laminarinase isolated from G. natalis was estimated to have a molecular mass of 41 kDa by SDS-PAGE and 71 kDa by gel filtration chromatography. A similar discrepancy was noted for C. destructor. Possible reasons for this are discussed. Laminarinase (EC 3.2.1.6) from G. natalis had a V_max of 42.0 µmol reducing sugars produced min–¹ mg protein–¹, a K_m of 0.126% (w/v) and an optimum pH range of 5.5–7, and hydrolysed mainly β-1,3-glycosidic bonds. In addition to the hydrolysis of β-1,3-glycosidic bonds, laminarinase (EC 3.2.1.39) from C. destructor was capable of significant hydrolysis of β-1,4-glycosidic bonds. It had a V_max of 19.6 µmol reducing sugars produced min^–1 mg protein^–1, a K_m of 0.059% (w/v) and an optimum pH of 5.5. Laminarinase from both species produced glucose and other short oligomers from the hydrolysis of laminarin. Endo-β-1,4-glucanase (EC 3.2.1.4) from G. natalis had a molecular mass of 52 kDa and an optimum pH of 4–7. It mainly hydrolysed β-1,4-glycosidic bonds, but was also capable of significant hydrolysis of β-1,3-glycosidic bonds. Two endo-β-1,4-glucanases, termed 1 and 2, with respective molecular masses of 53±3 and 52 kDa, were purified from C. destructor. Endo-β-1,4-glucanase 1 was only capable of hydrolysing β-1,4-glycosidic bonds and had an optimum pH of 5.5. Endo-β-1,4-glucanases from both species produced some glucose, cellobiose and other short oligomers from the hydrolysis of carboxymethyl cellulose.

Studies on the behaviour of polystyrene in reversed phase chromatography

Polystyrene behaviour in reversed phase high performance liquid chromatography was influenced mainly by the solvent system, but secondary affects were observed depending on the stationary phase. A variety of reversed phase columns were investigated using mobile phase combinations of dichlorom ethane-methanol, dichloromethane-acetonitrile, ethyl acetate-methanol and ethyl acetate-acetonitrile. Several different modes of behaviour were observed depending on the polymer solubility in the solvent system. In the dichloromethane-methanol solvent system, polymer-stationary phase interactions only occurred when the molecules had pore access. Retention of excluded polystyrene depended on the kinetics of precipitation and redissolution of the polymer. Peak splitting and band broadening occurred when the kinetics were slow and molecular weight separations were limited !o oligomers and polystyrenes lower than 5-10(4) dalton. Excellent molecular weight separations of polystyrenes were obtained using gradient elution reversed phase chromatography with a dichloromethane-acetonitrile mobile phase on C18 columns. The retention was based on polymer-stationary phase interactions regardless of the column pore size. Separations were obtained on large diameter pellicular adsorbents that were almost as good as those obtained on porous adsorbents, showing that pore access was not essential for the retention of high molecular weight polystyrenes. In the best example, the separation ranged from the monomer to 10(6) dalton in a single analysis. Very little adsorption of excluded polymers was observed on C8 or phenyl columns. Polystyrene molecular weight separations to 7-10(5) dalton were obtained in an ethyl acetate-acetonitrile solvent system on C18 columns. Adsorption was responsible for retention. When an ethyl acetate-methanol solvent system was used, no molecular weight separations were obtained because of complex peak splitting. Reversed phase chromatography was compared to size exclusion chromatography for the analysis of polydisperse polystyrenes. Similar results were obtained using both methods. However, the reversed phase method was less sensitive to concentration effects and gave better resolution.

Mechanism of permanganate chemiluminescence

Spectroscopic and synthetic methods have been exploited to deduce the mechanism for acidic potassium permanganate chemiluminescence. We have employed electron paramagnetic resonance (EPR) spectroscopy with a continuous flow assembly to monitor the formation of radical intermediates in real time generated from substrate oxidation by manganese(VII). These transient species react with manganese(III) in solution to produce the  previously characterized manganese(II)* emission source. Using UV-vis, EPR, attenuated total reflection (ATR)-FTIR, and chemiluminescence spectroscopies, we have established that there are two distinct enhancement mechanisms that in combination afford a 50-fold increase in emission intensity when the reaction is conducted in the presence of phosphate oligomers. In addition to preventing disproportionation of the manganese(III) precursor, the phosphate oligomers form protective "cagelike” structures around the manganese(II)* emitter, thus preventing nonradiative relaxation pathways.

The last piece in the cellulase puzzle : the characterisation of β-glucosidase from the herbivorous gecarcinid land crab Gecarcoidea natalis

A 160 kDa enzyme with β-glucosidase activity was purified from the midgut Gland of the land crab Gecarcoidea natalis. The enzyme was capable of releasing glucose progressively from cellobiose, cellotriose or cellotetraose. Although β-glucosidases (EC 3.2.1.21) have some activity towards substrates longer than cellobiose, the enzyme was classified as a glucohydrolase (EC 3.2.1.74) as it had a preference for larger substrates (cellobiose<cellotriose=cellotetraose). It was able to synthesise some cellotetraose by the transglycosylation of smaller substrates – another common feature of glucohydrolases. The interaction between the glucohydrolase described here and the endo-β-1,4-glucanases described previously for G. natalis provides a complete model for cellulose hydrolysis in crustaceans and possibly in other invertebrates. After mechanical fragmentation by the gastric mill, multiple endo-β-1,4-glucanases would initially cleave β-1,4-glycosidic bonds within native cellulose, releasing small oligomers, including cellobiose, cellotriose and cellotetraose. The glucohydrolase would then attach to these oligomers, progressively releasing glucose. The glucohydrolase might also attach directly to crystalline cellulose to release glucose from free chain ends. This two-enzyme system differs from the traditional model, which suggests that total cellulose hydrolysis requires the presence an endo-β-1,4-glucanse, a cellobiohydrolase and a β-glucosidase

Electrochemiluminescent monomers for solid support syntheses of Ru(II)-PNA bioconjugates : multimodal biosensing tools with enhanced duplex stability

The feasibility of devising a solid support mediated approach to multimodal Ru(II)-peptide nucleic acid (PNA) oligomers is explored. Three Ru(II)-PNA-like monomers, [Ru(bpy)2(Cpp-L-PNA-OH)]2+ (M1), [Ru(phen)2(Cpp-L-PNA-OH)]2+ (M2), and [Ru(dppz)2(Cpp-L-PNA-OH)]2+ (M3) (bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline, dppz = dipyrido[3,2-a:2′,3′-c]phenazine, Cpp-L-PNA-OH = [2-(N-9-fluorenylmethoxycarbonyl)aminoethyl]-N-[6-(2-(pyridin-2yl)pyrimidine-4-carboxamido)hexanoyl]-glycine), have been synthesized as building blocks for Ru(II)-PNA oligomers and characterized by IR and 1H NMR spectroscopy, mass spectrometry, electrochemistry and elemental analysis. As a proof of principle, M1 was incorporated on the solid phase within the PNA sequences H-g-c-a-a-t-a-a-a-a-Lys-NH2 (PNA1) and H-P-K-K-K-R-K-V-g-c-a-a-t-a-a-a-a-lys-NH2 (PNA4) to give PNA2 (H-g-c-a-a-t-a-a-a-a-M1-lys-NH2) and PNA3 (H-P-K-K-K-R-K-V-g-c-a-a-t-a-a-a-a-M1-lys-NH2), respectively. The two Ru(II)-PNA oligomers, PNA2 and PNA3, displayed a metal to ligand charge transfer (MLCT) transition band centered around 445 nm and an emission maximum at about 680 nm following 450 nm excitation in aqueous solutions (10 mM PBS, pH 7.4). The absorption and emission response of the duplexes formed with the cDNA strand (DNA: 5′-T-T-T-T-T-T-T-A-T-T-G-C-T-T-T-3′) showed no major variations, suggesting that the electronic properties of the Ru(II) complexes are largely unaffected by hybridization. The thermal stability of the PNA·DNA duplexes, as evaluated from UV melting experiments, is enhanced compared to the corresponding nonmetalated duplexes. The melting temperature (Tm) was almost 8 °C higher for PNA2·DNA duplex, and 4 °C for PNA3·DNA duplex, with the stabilization attributed to the electrostatic interaction between the cationic residues (Ru(II) unit and positively charged lysine/arginine) and the polyanionic DNA backbone. In presence of tripropylamine (TPA) as co-reactant, PNA2, PNA3, PNA2·DNA and PNA3·DNA displayed strong electrochemiluminescence (ECL) signals even at submicromolar concentrations. Importantly, the combination of spectrochemical, thermal and ECL properties possessed by the Ru(II)-PNA sequences offer an elegant approach for the design of highly sensitive multimodal biosensing tools.

Molecular aspects of boundary lubrication by human lubricin : effect of disulfide bonds and enzymatic digestion

Lubricin (LUB) is a glycoprotein of the synovial cavity of human articular joints, where it serves as an antiadhesive, boundary lubricant, and regulating factor for the cartilage surface. It has been proposed that these properties are related to the presence of a long, extended, heavily glycosylated and highly hydrated mucinous domain in the central part of the LUB molecule. In this work, we show that LUB has a contour length of 220 ± 30 nm and a persistence length of ≤10 nm. LUB molecules aggregate in oligomers where the protein extremities are linked by disulfide bonds. We have studied the effect of proteolytic digestion by chymotrypsin and removal of the disulfide bonds, both of which mainly affect the N− and C− terminals of the protein, on the adsorption, normal forces, friction (lubrication) forces, and wear of LUB layers adsorbed on smooth, negatively charged mica surfaces, where the protein naturally forms lubricating polymer brush-like layers. After in situ digestion, the surface coverage was drastically reduced, the normal forces were altered, and both the coefficient of friction and the wear were dramatically increased (the COF increased to μ = 1.1−1.9), indicating that the mucinous domain was removed from the surface. Removal of disulfide bonds did not change the surface coverage or the overall features of the normal forces; however, we find an increase in the friction coefficient from μ = 0.02−0.04 to μ = 0.13−1.17 in the pressure regime below 6 atm, which we attribute to a higher affinity of the protein terminals for the surface. The necessary condition for LUB to be a good lubricant is that the protein be adsorbed to the surface via its terminals, leaving the central mucin domain free to form a low-friction, surface-protecting layer. Our results suggest that this “end-anchoring” has to be strong enough to impart the layer a sufficient resistance to shear, but without excessively restricting the conformational freedom of the adsorbed proteins.

Expressão de uma quitinase de Metarhizium anisopliae em Nicotiana tabacum : obtenção de plantas transgênicas resistentes a doenças fúngicas

A resistência a doenças em plantas transgênicas tem sido obtida por meio da expressão de genes isolados de bactérias, fungos micoparasitas e plantas. Neste trabalho, relatamos a utilização de um gene do fungo entomopatogênico Metarhizium anisopliae como modo de gerar resistência a doenças fúngicas em plantas. O gene chit1 codifica a quitinase CHIT42 (EC 3.2.1.14), pertencente a uma classe de glicosil-hidrolases capazes de converter quitina em oligômeros de N-acetil-glicosamina (NAcGlc). Quando presentes em tecidos vegetais, supõese que as quitinases ataquem especificamente a parede celular de fungos invasores, provocando danos às hifas e causando a morte por lise das células fúngicas. Deste modo, dois diferentes grupos de plantas transgênicas de Nicotiana tabacum foram produzidos: no primeiro deles, denominado chitplus, os indivíduos possuem o gene chit1 sob o controle do promotor CaMV 35S. O segundo grupo, demoninado chitless, consiste de plantas transformadas com um T-DNA não contendo o gene do fungo. Trinta e quatro plantas transgênicas resistentes à canamicina (17 de cada grupo) foram regeneradas a partir de discos de folhas infectados por Agrobacterium tumefaciens. A produção da quitinase em extratos protéicos de folhas foi analisada por zimogramas em SDS-PAGE contendo glicol-quitina e corados por calcoflúor branco, na forma de um screening dos transgênicos primários. As plantas transgênicas foram testadas, ainda, por meio de ensaios colorimétricos empregando oligômeros sintéticos de NAcGlc como substratos específicos, além de immunoblot e Western blot com soro anti-quitinase. A quantidade de enzima recombinante nas plantas chitplus variou desde nenhuma atividade detectável a elevados níveis de expressão da enzima. A hibridização de Southern blot demonstrou que o número de cópias do gene chit1 integradas no genoma vegetal foi estimado entre uma e quatro. A primeira geração de plantas transgênicas geradas por autofecundação de parentais portadores de duas cópias do transgene foi testada com relação à estabilidade da herança do transgene e em 43 de um total de 67 descendentes, originados de quatro cruzamentos independentes, o padrão de segregação não diferiu das proporções Mendelianas esperadas. Ensaios de resistência, desafiando as plantas transgênicas com o basidiomiceto Rhizoctonia solani foram realizados e uma evidente diminuição da área foliar contendo lesões fúngicas foi observada entre as linhagens transgênicas, embora variações na atividade quitinolítica tenham influenciado o nível de resistência. Nossos resultados sugerem uma relação direta entre a atividade específica de quitinase e ao aumento nos níveis de resistência às lesões causadas pela infecção por R. solani.

Produção e caracterização de quitooligossacarídeos produzidos pelo fungo Metarhizium anisopliae e avaliação da citotoxicidade em células tumorais

Chitosan is a natural polymer, biodegradable, nontoxic, high molecular weight derived from marine animals, insects and microorganisms. Oligomers of glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) have interesting biological activities, including antitumor effects, antimicrobial activity, antioxidant and others. The alternative proposed by this work was to study the viability of producing chitooligosaccharides using a crude enzymes extract produced by the fungus Metarhizium anisopliae. Hydrolysis of chitosan was carried out at different times, from 10 to 60 minutes to produce chitooligosaccharides with detection and quantification performed by High Performace Liquid Chromatography (HPLC). The evaluation of cytotoxicity of chitosan oligomers was carried out in tumor cells (HepG2 and HeLa) and non-tumor (3T3). The cells were treated for 72 hours with the oligomers and cell viability investigated using the method of MTT. The production of chitosan oligomers was higher for 10 minutes of hydrolysis, with pentamers concentration of 0.15 mg/mL, but the hexamers, the molecules showing greater interest in biological properties, were observed only with 30 minutes of hydrolysis with a concentration of 0.004 mg/mL. A study to evaluate the biological activities of COS including cytotoxicity in tumor and normal cells and various tests in vitro antioxidant activity of pure chitosan oligomers and the mixture of oligomers produced by the crude enzyme was performed. Moreover, the compound with the highest cytotoxicity among the oligomers was pure glucosamine, with IC50 values of 0.30; 0.49; 0.44 mg/mL for HepG2 cells, HeLa and 3T3, respectively. Superoxide anion scavenging was the mainly antioxidant activity showed by the COS and oligomers. This activity was also depending on the oligomer composition in the chitosan hydrolysates. The oligomers produced by hydrolysis for 20 minutes was analyzed for the ability to inhibit tumor cells showing inhibition of proliferation only in HeLa cells, did not show any effect in HepG2 cells and fibroblast cells (3T3)

Modificação superficial do tecido 100% algodão tratado com plasma

The 100% cotton fabric (CO)* treated with plasma of methane CH4 has direct application in all areas that needs of aqueous solutions repellent material like coatings and uniforms applied biomedical, aeronautics, and automobile between others. 100% cotton fabric (CO) samples were treated by plasma with two differents atmosphere: Methane gas (CH4), treatment time was varied in 10 in 10 min. until 60 min., and mixture methane/argon (CH4/Ar), it was varied the proportion 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2 e 9:1, with treatment time of 30 minutes. In both, the fluxe was 5 sccm (second cubic centimeter), pressure 6 mbar, voltage 490 V and current 0,15A. The objective of work was measure the superficial tension of 100% CO then it treated with plasma, using contact angle measures of water and glycerol with the surface. The samples were tested after treatment, with 8 and 12 months to verify the superficial modification effects. It was verified an increase of hydrophobility with the Sessile drop values varied between 116,69º to 137,85º and it carried on after 12 months. The no treated samples shows contact angle equal 0º. OES analysis and Raman spectroscopy were accomplished. In the SEM analysis was verified oligomers. The plasma treatment is correct environmental, It turning greater than conventional treatments

Estudo do mecanismo de produção de oligossacarídeos com atividades nutracêuticas a partir da quitosana por hidrólise enzimática com processo fermentativo simultâneo

The obtaining of the oligosaccharides from chitosanase, has showed interest of the pharmaceutical area in the last years due their countless functional properties. Although, the great challenge founded out is how to keep a constant and efficient production. The alternative proposed by this present work was to study the viability to develop an integrated technology, with reduced costs. The strategy used was the obtaining of the oligomers through enzymatic hydrolysis using chitosanolitic enzymes obtained straight from the fermented broth, eliminating this way the phases involved in the enzymes purification. The two chitosanases producing strains chosen for the work, Paenibacillus chitinolyticus and Paenibacillus ehimensis, were evaluated according to the behavior in the culture medium with simple sugar and in relation to the pH medium variations. The culture medium for the chitosanases induction and production was developed through addition of soluble chitosan as carbon source. The soluble chitosan was obtained using hydrochloric acid solution 0.1 M and afterwards neutralization with NaOH 10 M. The enzymatic complexes were obtained from induction process in culture medium with 0.2% of soluble chitosan. The enzymes production was verified soon after the consumption of the simple sugars by the microorganisms and the maximum chitosanolitic activity obtained in the fermented broth by Paenibacillus chitinolyticus was 249 U.L-1 and by Paenibacillus ehimensis was 495U.L-1. These two enzymatic complexes showed stability when stored at 20°C for about 91 days. The enzymes in the fermented broth by Paenibacillus chitinolyticus, when exposed at temperature of 55°C and pH 6.0, where the activity is maximum, showed 50% lost of activity after 3 hours Meanwhile, for the complex produced by Paenibacillus ehimensis, after 6 days of exposure, it was detected 100% of the activity. The chito-oligosaccharides obtained by the hydrolysis of a 1% chitosan solution, using the enzymatic complex produced by Paenibacillus chitinolyticus showed larger quantity after 9 hours hydrolysis and using the complex produced by Paenibacillus ehimensis after 20 minutes was observed the chito-ligosacharides with polymerization degree between 3 and 6 units. Evaluating these results, it was verified that the production of chitosan-oligosaccharides is possible, using a simultaneous process