The gut microbiota of the wood-feeding termite Reticulitermes lucifugus (Isoptera; Rhinotermitidae)

Termite gut is host to a complex microbial community consisting of prokaryotes, and in some cases flagellates, responsible for the degradation of lignocellulosic material. Here we report data concerning the analysis of the gut microbiota of Reticulitermes lucifugus (Rossi), a lower termite species that lives in underground environments and is widespread in Italy, where it causes damage to wood structures of historical and artistic monuments. A 16S rRNA gene clone library revealed that the R. lucifugus gut is colonized by members of five phyla in the domain Bacteria: Firmicutes (49 % of clones), Proteobacteria (24 %), Spirochaetes (14 %), the candidatus TG1 phylum (12 %), and Bacteroidetes (1 %). A collection of cellulolytic aerobic bacteria was isolated from the gut of R. lucifugus by enrichment cultures on different cellulose and lignocellulose substrates. Results showed that the largest amount of culturable cellulolytic bacteria of R. lucifugus belongs to Firmicutes in the genera Bacillus and Paenibacillus (67 %). These isolates are also able to grow on xylan and show the largest clear zone diameter in the Congo red test. Reticulitermes lucifugus hosts a diverse community of bacteria and could be considered an acceptable source of hydrolytic enzymes for biotechnological applications

Transcatheter closure of atrial septal defect in young children Results and follow-up

AbstractObjectivesThis study sought to analyze the safety, efficacy, and follow-up results of percutaneous closure of secundum atrial septal defect (ASD) in young children.BackgroundResults of ASD transcatheter closure in adults are widely reported but there are no large published series concerning young children.MethodsBetween December 1996 and February 2002, 48 of 553 patients percutaneously treated at our institution were children age ≤5 years. Indications for closure were: elective closure in 32 patients; frequent respiratory infections in 8; failure to thrive in 2; liver transplantation in 5; and a fenestrated Fontan in 1. The procedure was carried out under general anesthesia with fluoroscopy and transesophageal control. Two different devices were used: 1) the CardioSEAL/StarFLEX (CS/SF) and 2) the Amplatzer septal occluder (ASO). Basal physical examinations and echocardiograms were performed prior to the procedure and at follow-ups (1, 6, and 12 months, and yearly thereafter).ResultsThe mean age at closure was 3.6 ± 1.3 years. A CS/SF was used in 10 subjects; an ASO was used in 38 patients. No deaths or immediate major complications occurred. The total occlusion rate was 87% at procedure, rising to 94% at discharge. The mean follow-up was 18 ± 14 months. No midterm major or minor complications occurred. The occlusion rate rose to 100% at 12 months of follow-up. Symptomatic patients improved significantly.ConclusionsIn the current era and in experienced hands, ASD closure can be performed safely and successfully, even in very young children

Regeneration of cellulose by water addition to phosphoric acid/cellulose mixture

In the last years, phosphoric acid has been increasingly considered as a simple and economic solvent for cellulose pretreatment before its degradation to glucose. Cellulose swells in 71–80% phosphoric acid solutions, whereas at higher H3PO4 concentrations dissolution appears to occur. In addition, it is reported that regenerated cellulose is more easily fermentable to bioethanol. The aim of the present study was to elucidate the mechanism for cellulose regeneration following treatment with phosphoric acid at room temperature. CPMAS 13C NMR spectra revealed a downfield shift of the 13C NMR signals from the regenerated cellulose as compared to the crystalline one. CPMAS 31P NMR spectroscopy showed presence of organic phosphate in the regenerated cellulose. These results suggested that cellulose regeneration consisted in the precipitation of a phosphorylated polymer. Fast field cycling NMR relaxometry confirmed such hypothesis. In fact, the correlation time of water saturated crystalline cellulose was shorter than that measured for the water saturated regenerated cellulose. The phosphate groups bound to the regenerated cellulose surface allow restriction of water mobility, thereby producing longer correlation times. Finally turbidimetric analyses revealed that the mechanism of regeneration consisted in a first reduction of the colloidal cellulose size followed by aggregation, colloidal size increment and flocculation. This study is of paramount importance to understand how phosphoric acid interact with cellulose in order to address its possible uses in biomass transformation for bioenergy purposes

Transcatheter Closure of Perimembranous Ventricular Septal Defects

n/

Analisi della comunità microbica intestinale di Reticulitermes lucifugus (Rossi) (Isoptera: Rhinotermitidae).

L’intestino delle termiti ospita una comunità microbica di batteri e flagellati anaerobi, responsabile della degradazione del materiale lignocellulosico. La digestione della lignocellulosa da parte delle termiti dipende dalla simbiosi con microrganismi procarioti ed eucarioti che vivono nel loro intestino. I microrganismi trasformano la cellulosa in zuccheri e acetato, producendo idrogeno, metano e anidride carbonica. Abbiamo analizzato la comunità microbica intestinale di Reticulitermes lucifugus lucifugus, una delle due specie di termiti italiane, che vive in ambienti sotterranei, è distruttiva per le strutture legnose degli ambienti urbani causando seri danni ai monumenti storici e può colonizzare le abitazioni, scavando gallerie all'interno di pali di sostegno, travi e tavole. Studi preliminari sulla comunità microbica dei simbionti di R. lucifugus, hanno descritto alcune specie di protozoi (e.g. Dynenympha sp., Pyrsonimpha flagellata Leidy, Spyrotriconimpha flagellata Grassi e Foà, Holomastigotes elongatum, Triconympha agilis Leidy) ma non ci sono ancora informazioni sui simbionti batterici. Dall’intestino della termite è stato estratto il DNA metagenomico, da cui è stato amplificato l’rDNA 16S tramite PCR (polymerase chain reaction), usando primers universali per i procarioti. E’ stata costruita una libreria i cui cloni sono stati raggruppati in OTU (Operational Taxonomic Units) tramite analisi ARDRA (Amplified Ribosomal DNA Restriction Analysis). Per ogni OTU sono stati sequenziati uno o più cloni e le sequenze sono state confrontate con quelle presenti in banca dati. L’analisi delle sequenze ha evidenziato che la comunità microbica di Reticulitermes lucifugus lucifugus è molto diversificata, sono presenti clostridi, beta e delta proteobatteri, batteri appartenenti al genere Treponema and Uncultured Termite group I, presenti nel microbiota di altre temiti Inoltre per isolare la frazione di batteri cellulosolitici dall’intestino di Reticulitermes lucifugus lucifugus, sono state allestite colture di arricchimento su diversi substrati, quali carta, eucalipto, pino, noce e CMC (carbossimetilcellulosa). Gli isolati ottenuti sono stati caratterizzati e alcuni, risultati positivi al test del rosso congo, identificati. I risultati preliminari di questa analisi mostrano una prevalenza di batteri gram positivi low GC appartenenti al genere Bacillus, ma anche di alpha e beta proteobacteria.La conoscenza più approfondita delle specie batteriche presenti nell’intestino di Reticulitermes lucifugus lucifugus potrebbe fornire utili informazioni per contrastare il loro attacco alle strutture legnose, contribuendo così a preservare il patrimonio artistico italiano

BIOCHAR SURFACE PROPERTIES THROUGH APPLICATION OF AN INNOVATIVE NMR TECHNIQUE: FAST FIELD CYCLING RELAXOMETRY

Biochar is a carbonaceous material obtained by pyrolysis of biomass feedstocks. It is applied to soils in order to improve fertility and mitigate greenhouse-gases emissions. In fact, from the one hand, biochar changes physical-chemical soil properties, thereby affecting soil fertility. From the other hand, biochar is resistant to chemical and biochemical degradation. For this reason, its use allows carbon sequestration in soils and consequent reduction of carbon dioxide to the atmosphere. Here, dynamics of water at the liquid-solid interface of water saturated biochars is discussed. Results revealed that water dynamics is affected by the nature of biochar parent biomasses. Moreover, biochar chemical physical properties are affected by conditions for their production. It was understood that water undergoes to an inner-sphere interaction mechanism with biochar surface through formation of weak unconventional hydrogen bonds. Recognition of the interaction mechanisms between water and biochar is of paramount importance in order to understand why biochar soil amendments improve soil fertility and crop production

Effect of texture on the dynamics of a water saturated biochar

Biochar is defined as charred organic matter applied to soil in a deliberate manner, with the intent to improve soil properties (Lehmann et al., 2009). Biomass-derived char can be used as energy carrier, as adsorber and as material for the improvement of soil properties. Carbonized organic matter can have different physical and chemical properties depending on the technology used for its production. Moreover char texture influences deeply physical and chemical properties. In this work effect of texture on the dynamics of a water saturated biochar was analyzed by FFC NMR. An industrial biochar derived from gasification of poplar wood was sieved to determine influence of texture on water dynamic on particles surface. Sieves with 2, 1 and 0.3 mm have been used to separate three different texture fractions. Each sample has been saturated with water and then analysed by FFC NMR relaxometry by applying a range of magnetic field from 40MHz to 0.01MHz. Three profiles with different longitudinal relaxation rate have been carried out. Sample with texture 1-2mm has a profile with the lowest longitudinal relaxation rate (R1). Profile of sample with textures <0.3mm has the profile with highest R1. Behavior of water can be explained associating an increment of longitudinal relaxation rate with an increment of porosity. Surface area reduction is achieved when the sizes of the pores increase. As water molecules flow through larger sized pores, their motion occurs at a frequency that is broader than that of water molecules constrained in smaller sized pores. For this reason quickly moving water can not efficaciously interact with either neighboring molecules or with the molecular sites on the surface at the liquid-solid interface. As a consequence intermolecular dipolar interactions are weakened and a reduction of the proton longitudinal relaxation rate (shorter R1 values) can be observed compared with the R1 values for slowly moving or immobilized water systems

Degradazione termica di biomasse lignocellulosiche in acido fosforico

La lignocellulosa è la più abbondante fonte rinnovabile per la produzione di bioetanolo. Sfortunatamente la produzione di biocarburanti liquidi da scarti lignocellulosici presenta molti inconvenienti a causa della compattezza e della complessità di questi materiali, caratteristiche che rendono molto più difficoltosa la loro degradazione enzimatica in zuccheri fermentabili rispetto ad altri biopolimeri come l’amido. Inoltre il costo della produzione di bioetanolo da biomasse lignocellulosiche è ancora molto alto rispetto a quello dei processi industriali che utilizzano come materiale di partenza l’amido. Obiettivo del presente studio è quello di testare su campioni di biomassa lignocellulosica un metodo di degradazione acida messo a punto sulla cellulosa microcristallina, al fine di ottenere zuccheri fermentabili per la produzione di bioetanolo. La biomassa utilizzata in questo studio è ottenuta dalla potatura di viti. Un’aliquota di biomassa viene posta in acido fosforico e riscaldata a 80°C per un tempo variabile nell’intervallo 15-300 minuti. Il supernatante viene separato ed analizzato mediante analisi colorimetrica per individuare la concentrazione di zuccheri riducenti. Il residuo solido viene prima lavato, poi seccato ed infine analizzato in spettroscopia CPMAS 13C NMR. Il risultato delle indagini colorimetriche ha mostrato che a circa 120 minuti si raggiunge il massimo della concentrazione di zuccheri riducenti. A partire da 150 minuti si osserva la diminuzione della concentrazione di zuccheri dovuta alla degradazione degli stessi come descritto già in Butera et al. (2011). Le analisi in spettroscopia CPMAS 13C NMR hanno messo in evidenza come il trattamento in acido fosforico consenta l’estrazione della cellulosa dalla biomassa solida. Infatti gli spettri NMR della componente solida dopo 60 minuti di trattamento contengono unicamente segnali di lignina. Questi risultati hanno trovato conferma nelle misure di rilassometria FFC NMR condotte sulla biomassa tal quale e sui solidi sottoposti ad idrolisi acida. Dopo trattamento con acido fosforico si osserva una diminuzione del T1(H) seguita da un progressivo aumento. La diminuzione è attribuibile al fatto che si ha depolimerizzazione dovuta all’idrolisi acida della cellulosa e dell’emicellulosa, i principali componenti delle biomasse lignocellulosiche. Man mano che si allontana il residuo polisaccaridico, si ottiene un innalzamento del T1(H) perché si «isola» la lignina altro polimero funzionale del residuo usato per questi esperimenti

Thermal degradation of microcrystalline cellulose in concentrated phosphoric acid

The most common renewable fuel is ethanol. It is a liquid produced by fermentation of glucose which is very abundant in cellulose based materials. Bioethanol is achieved in a two-steps process: 1. hydrolysis of the cellulose included in the ligno-cellulosic materials to fermentable reducing sugars; 2. fermentation of such sugars to ethanol. While the second fermentation step, mediated by yeasts or bacteria, is very well established, the first one must be still assessed for process optimization. Many efforts have been made to identify solvents for cellulose in order to develop methods for the achievement of fermentable glucose. In the presence of mineral acid, cellulose undergoes hydrolysis whose extent depends on acid concentration, reaction temperature and duration of treatment. In the last years, dissolution in phosphoric acid (a weak mineral acid, non toxic and safer to use as compared to other inorganic acids) has been increasingly considered as a simple and economic method for cellulose pretreatment before its degradation to glucose. Up to now, it has not been reported yet cellulose conversion to glucose in H3PO4 solutions. Aim of the present study was to evaluate kinetic of glucose formation during cellulose degradation by using 85% phosphoric acid. It was investigated the role of residence time on the efficiency of glucose release during the hydrolysis of microcrystalline- cellulose in H3PO4 at the constant reaction temperature of 80°C. Moreover, High field NMR measurements showed that heating treatment is fundamental to have conversion of cellulose in glucose with formation of same degradation products, how supported by GC MS analysis results. In addition, relaxometry measurements with a fast field cycling setup have been carried out in order to observe how heating treatment change the relaxation time distribution of cellulose acid solutions, thereby suggesting that as cellulose degradation occurred , presence of smaller units determined the restoring of the T1 distribution of the complex mixture to a value close to that of pure phosphoric acid