In this work, fundamental aspects on the ultrasonic velocity monitoring of alcoholic fermentations in synthetic broths (glucose, fructose and sucrose) and natural media (must and wort) are reported. Results are explained in terms of monosaccharide catabolism, polysaccharide hydrolysis, gas production and microorganism growth. The effect of each one of these subprocesses upon ultrasonic velocity has been independently studied. It is shown that, regarding the sound propagation, the simplest systems behave as ternary dissolutions of sugar and ethanol in water, where, in the course of time, substrates are transformed into metabolites according to the fermentation reaction. A semi-empirical approach, based on the excess volume concept and the density and velocity measurements of binary mixtures, has been used to calculate these magnitudes in the ternary mixtures and to obtain the concentrations of the main solutes throughout the fermentations, reaching a good correlation (especially for the media of simplest composition). In all the processes analyzed, the data obtained from the ultrasonic measurements followed the changes caused by the yeast metabolism, asserting the potential of mechanical waves to monitor fermentations and, in general, biotechnological processes.
OBJECTIVES:To date, this is the largest prospective series in patients with malignant colorectal obstruction to evaluate the effectiveness and safety of colonic self-expanding metal stents (SEMSs) as an alternative to emergency surgery. SEMSs allow restoration of bowel transit and careful tumor staging in preparation for elective surgery, hence avoiding the high morbidity and mortality associated with emergency surgery and stoma creation.
METHODS:This report is on the SEMS bridge-to-surgery subset enrolled in two multicenter international registries. Patients were treated per standard of practice, with documentation of clinical and procedural success, safety, and surgical outcomes.
RESULTS:A total of 182 patients were enrolled with obstructive tumor in the left colon (85 % ), rectum (11 % ), or splenic fl exure (4 % ). Of these patients, 86 % had localized colorectal cancer without metastasis. Procedural success was 98 % (177 / 181). Clinical success was 94 % (141 / 150). Elective surgery was performed in 150 patients (9 stomas) and emergency surgery in 7 patients for treatment of a complication (3 stomas). The overall complication rate was 7.8 % (13 / 167), including perforation in 3 % (5 / 167), stent migration in 1.2 % (2 / 167), bleeding in 0.6 % (1 / 167), persistent colonic obstruction in 1.8 % (3 / 167), and stent occlusion due to fecal impaction in 1.2 % (2 / 167). One patient died from complications related to surgical management of a perforation.CONCLUSIONS: SEMSs provide an effective bridge to surgery treatment with an acceptable complication rate in patients with acute malignant colonic obstruction, restoring luminal patency and allowing elective surgery with primary anastomosis in most patients.
a b s t r a c tRepresenting around 40% of the cell wall dry weight, mannoproteins are complex macromolecules structurally composed of polymers of sugar, 98% being mannose, covalently linked to peptides. Along the last two decades, these compounds have gained ground as very relevant molecules in the field of winemaking, mainly due to their positive contributions in the development of appreciated organoleptic features and to their contribution in the chemical stabilization of wine. Several methodologies have been recently proposed to achieve the quantification of these compounds. However, these methodologies are laborious, time consuming and do not allow a global quantification of these macromolecules. In this paper, an easy, reliable and fast forward methodology for the quantification of mannoproteins in model must is proposed and evaluated. Its application in the quantification of mannoproteins content in yeast cell wall is also demonstrated.
The gene in the locus GALLO_1609 from Streptococcus gallolyticus UCN34 was cloned and expressed as an active protein in Escherichia coli BL21 (DE3). The protein was named TanSg1 since it shows similarity to bacterial tannases previously described. The recombinant strain produced His-tagged TanSg1 which was purified by affinity chromatography. Purified TanSg1 protein showed tannase activity, having a specific activity of 577 U/mg which is 41 % higher than the activity of Lactobacillus plantarum tannase. Remarkably, TanSg1 displayed optimum catalytic activity at pH 6-8 and 50-70 °C and showed high stability over a broad range of temperatures. It retained 25 % of its relative activity after prolonged incubation at 45 °C. The specific activity of TanSg1 is enhanced by the divalent cation Ca(2+) and is dramatically reduced by Zn(2+) and Hg(2+). The enzyme was highly specific for gallate and protocatechuate esters and showed no catalytic activity against other phenolic esters. The protein TanSg1 hydrolyzes efficiently tannic acid, a complex and polymeric gallotanin, allowing its complete conversion to gallic acid, a potent antioxidant. From its biochemical properties, TanSg1 is a tannase with potential industrial interest regarding the biodegradation of tannin waste or its bioconversion into biologically active products.
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