Aplicação da RMN na caracterização estrutural de glicolipideos e polissacarideos de Achatina fulica

Orientadores: Prof. Dr. Marcello Iacomini, Prof. Dr. Philip Albert James GorinDissertação( Mestrado ) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Curso de Pós-Graduação em BioquímicaInclui referências: p. 69-81Resumo: Glândulas de albúmen do molusco comestível Achatina fulica foram submetidas a processos de extração a fim de se obter glicolipídeos e polissacarídeos. Os deslocamentos químicos destas estruturas foram determinados. Assim foi caracterizado um polissacarídeo que demonstrou se uma galactan. Na análise destes métodos químicos foram empregados, como: produção por hidrolise acida parcial e purificação de oligossacarídeos, e degradações sequenciadas de Smith. O glicolipídeo isolado, através da interpretação dos dados de RMN demonstrou ser o composto O-B-D-Glcp-(11)-D-glicerol, e que os principais ácidos graxos presentes são ác. palmítico e aracdônico

The GRAVITY+ Project: Towards All-sky, Faint-Science, High-Contrast Near-Infrared Interferometry at the VLTI

The GRAVITY instrument has been revolutionary for near-infrared interferometry by pushing sensitivity and precision to previously unknown limits. With the upgrade of GRAVITY and the Very Large Telescope Interferometer (VLTI) in GRAVITY+, these limits will be pushed even further, with vastly improved sky coverage, as well as faint-science and high-contrast capabilities. This upgrade includes the implementation of wide-field off-axis fringe-tracking, new adaptive optics systems on all Unit Telescopes, and laser guide stars in an upgraded facility. GRAVITY+ will open up the sky to the measurement of black hole masses across cosmic time in hundreds of active galactic nuclei, use the faint stars in the Galactic centre to probe General Relativity, and enable the characterisation of dozens of young exoplanets to study their formation, bearing the promise of another scientific revolution to come at the VLTI.Comment: Published in the ESO Messenge

Production of Cellulose and Profile Metabolites by Fermentation of Glycerol by Gluconacetobacter Xylinus

ABSTRACT Because of the widespread occurrence of cellulose in nature, many organisms use glycerol as a source of carbon and energy, so these organisms have drawn attention to the potential use of glycerol bioconversion. The bacteria Gluconacetobacter xylinus, a strictly aerobic strain that performing incomplete oxidation of various sugars and alcohols to cellulose biosynthesis. For this reason, we modify the Hestrim-Schram medium, associating glycerol, glucose and sucrose varying their concentration. The fermentations were performed statically at a temperature of 28˚C for a period of 10 days. The pH, membrane formation, crystallinity and the production of some metabolites of the 4th, 7th and 10th days was evaluated. The results showed a higher yield of membrane in the medium containing glucose, gly 1 + glu2 on 10 fermentation of 3.5 g %. Through solid-state NMR gave the crystallinity of the membranes, where there was a clear trend toward higher crystallinity membranes with 7 days of fermentation. Metabolic products found in the media by analysis of NMR spectroscopy in liquid were similar, especially for the production of alanine and lactate that were present in all media. The leucine and threonine were present in various media, although in small quantities has been found glutamate

Bacterial cellulose and hyaluronic acid hybrid membranes: Production and characterization

AbstractIn this study, the effect of the addition of hyaluronic acid (HA) on bacterial cellulose (BC) production, under static conditions was evaluated in terms of the properties of the resulting BC hybrid membranes. HA was added to the fermentation process in three distinct time points: first day (BC-T0), third day (BC-T3) and sixth day (BC-T6). Analyses of FT-IR and CP/MAS 13C NMR confirmed the presence of HA in bacterial cellulose membranes. The crystal structure, crystallinity index (Ic) surface roughness, thermal stability and hybrophobic/hydrophilic character changed. Membranes with higher roughness were produced with HA added on the first and third day of fermentation process. The surface energy of BC/HA membranes was calculated and more hydrophilic membranes were produced by the addition of HA on the third and sixth day, also resulting in more thermally stable materials. The results demonstrate that bacterial cellulose/hyaluronic acid hybrid membranes can be produced in situ and suggest that HA interacts with the sub-elementary bacterial cellulose fibrils, changing the properties of the membranes. The study and understanding of the factors that affect those properties are of utmost importance for the safe and efficient use of BC as biomaterials in numerous applications, specifically in the biological field

Preparation of cellulose II and IIII films by allomorphic conversion of bacterial cellulose I pellicles

International audienc

ISOLATION AND CHARACTERIZATION OF NANOFIBRILLATED CELLULOSE FROM OAT HULLS

The objectives of this work were to investigate the microstructure, crystallinity and thermal stability of nanofibrillated cellulose obtained from oat hulls using bleaching and acid hydrolysis at a mild temperature (45 ºC) followed by ultrasonication. The oat hulls were bleached with peracetic acid, and after bleaching, the compact structure around the cellulosic fibers was removed, and the bundles became individualized. The extraction time (30 or 60 min) did not affect the properties of the nanofibrillated cellulose, which presented a higher crystallinity index and thermal stability than the raw material (oat hulls). The nanocellulose formed interconnected webs of tiny fibers with diameters of 70-100 nm and lengths of several micrometers, producing nanofibers with a relatively high aspect ratio, thus indicating that these materials are suitable for polymer reinforcement

A bioinspired light induced avenue for the design of patterned functional interfaces

An avenue for the development of spatially resolved functional interfaces is presented. By introducing a novel, photo-reactive molecule-carrying a DOPA functionality and a photo-reactive group-we merge the ability of mussels to adhere to any surface with the spatial and temporal control of photo-click reactions, opening a plethora of applications in the biomedical and materials fields

Komagataeibacter intermedius V-05, bakterija octenog vrenja izolirana tijekom industrijske proizvodnje octa, s velikom sposobnošću proizvodnje bakterijske celuloze u podlozi od sojine melase

Research background. Despite the great properties of bacterial cellulose, its manufacture is still limited due to difficulties in large-scale production. These problems are mainly related to low production yields and high overall costs of the conventional culture media normally used. To surpass these problems, it is necessary to identify new cheap and sustainable carbon sources. Thus, this work aims to isolate and select a high cellulose-producing Komagataeibacter strain from vinegar industry, and study its potential for bacterial cellulose synthesis in an industrial soybean co-product, known as soybean molasses, used as fermentation medium. Experimental approach. One isolated strain was able to produce high amount of cellulose in the standard Hestrin-Schramm medium, so we tested its ability to produce this biopolymer in a soybean molasses medium. The characteristics and properties of the produced bacterial cellulose membranes were analyzed by thermogravimetric analysis, X-ray diffraction, infrared spectroscopy, water-holding capacity and rehydration ratio. Genetic analysis of the selected strain served to determine its genus and species. Results and conclusions. An isolated strain that produced the highest amount of cellulose in Hestrin-Schramm medium (3.7 g/L) was genetically identified as Komagataeibacter intermedius V-05. This strain produced 10.0 g/L of cellulose in soybean molasses medium. Membranes from both substrates had similar chemical structure, crystallinity and thermal degradation. Soybean molasses proved to be a suitable alternative medium for biosynthesis of cellulose in comparison with the standard medium. In addition to providing higher production yield, the membranes showed great structural characteristics, similar to those obtained from standard medium. Novelty and scientific contribution. In this research, we have isolated and identified a Komagataeibacter strain which exhibits a high capacity for cellulose production in soybean molasses. The isolation and selection of strains with high capacity for microbial metabolite production is important for decreasing bioprocess costs. Furthermore, as there is a necessity today to find cheaper carbon sources to obtain microbial products at a lower cost, soybean molasses represents an interesting alternative medium to produce bacterial cellulose for its industrial application.Pozadina istraživanja. Usprkos izvrsnim svojstvima bakterijske celuloze, njezina je proizvodnja još uvijek ograničena zbog poteškoća u provođenju proizvodnje na veliko, uglavnom zbog niskog prinosa i visokih troškova uzgoja u uobičajeno korištenim podlogama. Da bi se ti problemi zaobišli, potrebno je pronaći nove jeftine i održive izvore ugljika. Stoga je svrha ovoga rada bila tijekom postupka proizvodnje octa izolirati i odabrati soj bakterije Komagataeibacter koji može proizvesti velike količine celuloze, te ispitati njegovu sposobnost sinteze bakterijske celuloze u podlozi od sojine melase, jednom od nusproizvoda industrijskog uzgoja soje. Eksperimentalni pristup. Jedan je od izoliranih sojeva proizveo veliku količinu celuloze u standardnoj Hestrin-Schramm podlozi, pa smo ispitali može li proizvesti taj biopolimer i u podlozi od sojine melase. Glavne značajke i svojstva dobivene bakterijske celuloze ispitane su termogravimetrijskom analizom, rentgenskom difrakcijom, infracrvenom spektroskopijom, te mjerenjem sposobnosti vezanja vode i stupnja rehidracije. Genetičkom su analizom određeni rod i vrsta izoliranog soja bakterije. Rezultati i zaključci. Soj bakterije koji je proizveo najviše celuloze u Hestrin-Schramm podlozi (3,7 g/L) genetičkom je analizom identificiran kao Komagataeibacter intermedius V-05. U podlozi sa sojinom melasom taj je soj proizveo 10,0 g/L celuloze. Celulozne membrane dobivene uzgojem bakterije u obje podloge imale su sličnu kemijsku strukturu, podjednako svojstvo kristaliničnosti i sličnu toplinsku stabilnost. Sojina melasa pokazala se kao dobra alternativna standardnoj podlozi za biosintezu celuloze. Osim što je pomoću nje dobiven veći prinos celuloze, struktura dobivenih membrana bila je izuzetno dobra, slična membranama dobivenim uzgojem u standardnoj podlozi. Novina i znanstveni doprinos. U ovom smo radu izolirali i identificirali soj bakterije Komagataeibacter koji može uspješno proizvesti celulozu u podlozi od sojine melase. Izolacija i odabir sojeva koji mogu proizvesti velike količine mikrobnih metabolita vrlo su važni za smanjenje troškova bioprocesa. Uz to, budući da je u današnje vrijeme neophodno pronaći ekonomičnije izvore ugljika za jeftiniju proizvodnju mikrobnih proizvoda, sojina melasa predstavlja zanimljivu alternativu uobičajenoj podlozi za industrijsku proizvodnju bakterijske celuloze

Photo-patterning of non-fouling polymers and biomolecules on paper

Functional cellulose substrates with tetrazole moieties are generated to serve as universal platforms for the spatio-temporal immobilization of synthetic ultra-low fouling polymer brushes and protein species via a nitrile imine-mediated tetrazole-ene cycloaddition (NITEC)-based protocol. Poly(carboxybetaine acrylamide) brushes are grafted from initiators photo-patterned by NITEC utilizing single electron transfer living radical polymerization. Streptavidin is photo-immobilized with remarkable efficiency, opening the possibility to generate new materials for biomedical and biosensing applications