Topographical characteristics through the study of the thermal and hydrological disuniformity of the soil from the mesoscale. An appplication to local forecasting of ambient temperature from the TELLUS project

There are no author-identified significant results in this report

Modulating D-amino acid oxidase substrate specificity: production of an enzyme for analytical determination of all D-amino acids by directed evolution

Recent research on the flavoenzyme D-amino acid oxidase from Rhodotorula gracilis (RgDAAO) has revealed new, intriguing properties of this catalyst and offers novel biotechnological applications. Among them, the reaction of RgDAAO has been exploited in the analytical determination of the D-amino acid content in biological samples. However, because the enzyme does not oxidize acidic D-amino acids, it cannot be used to detect the total amount of D-amino acids. We now present the results obtained using a random mutagenesis approach to produce RgDAAO mutants with a broader substrate specificity. The libraries of RgDAAO mutants were generated by error-prone PCR, expressed in BL21(DE3)pLysS Escherichia coli cells and screened for their ability to oxidize different substrates by means of an activity assay. Five random mutants that have a 'modified' substrate specificity, more useful for the analytical determination of the entire content of D-amino acids than wild-type RgDAAO, have been isolated. With the only exception of Y223 and G199, none of the effective amino acid substitutions lie in segments predicted to interact directly with the bound substrate. The substitutions appear to cluster on the protein surface: it would not have been possible to predict that these substitutions would enhance DAAO activity. We can only conclude that these substitutions synergistically generate small structural changes that affect the dynamics and/or stability of the protein in a way that enhances substrate binding or subsequently catalytic turnover

Whole-Cell Bioconversion of Renewable Biomasses-Related Aromatics to cis,cis-Muconic Acid

Lignin and wheat bran represent renewable feedstocks for generation of useful and value-added compounds such as vanillin (a popular flavoring agent) and cis,cis-muconic acid (ccMA, a building block for the synthesis of plastic materials). In the present work, we report on the setup of an efficient and green process for producing such valuable compounds based on (a) the optimization of the extraction procedures for vanillin from lignin and ferulic acid from wheat bran and (b) the genetic engineering of an Escherichia coli strain with up to three plasmids differing in copy numbers to modulate the expression of up to seven recombinant enzymes. In detail, we used two sequential reactions catalyzed by the decarboxylase Fdc and the dioxygenase Ado to convert wheat bran-derived ferulic acid into vanillin: nature-identical vanillin was produced in one pot with a >85% yield in 20 h. Next, the dehydrogenase LigV, the demethylase VanAB, the decarboxylase AroY, and the dioxygenase C12O converted lignin-derived vanillin into ccMA with a >95% conversion yield and a productivity of 4.2 mg of ccMA/g of Kraft lignin in 30 min. Finally, when the optimized E. coli strain expressing all the abovementioned enzymes was used, ccMA was produced with a >95% conversion yield starting from ferulic acid in 10 h following product isolation, corresponding to 0.73 g of ccMA/g of ferulic acid, 1.4 g of ccMA/L, and 2.2 g of ccMA/g of wheat bran biomass. The optimized whole-cell system represents a sustainable and cost-competitive process for producing high value-added products from renewable resources

Practical use of blactchford score

Aim: To retrospectively evaluate the use of proton pump inhibitor infusions. Methods: A retrospective chart review was conducted of all patients who received an 80 mg bolus of esomeprazole follow by an infusion at 8 mg/hr. An analysis was performed to determine if a Blatchford Score of \u3e 5 was a predictor of upper gastrointestinal ulcers. Results: 300 patients received high dose esomeprazole over a 15 month period. 32% had an ulcer identified on endoscopy. Gastritis and esophagitis were the second most common diagnosis accounting for 16% of patients. A Blatchford Score of \u3e5 as a predictor of upper gastrointestinal ulcers had a sensitivity of 86.5% with a specificity of 32%. Conclusion: Utilizing the Blatchford Score to predict patients that have an upper gastrointestinal ulcer does not appear to be effective in clinical practice

Antibacterial Properties of D-Amino Acid Oxidase: Impact on the Food Industry

Food quality is also related to safety and prevention of spoilage. Biological antimicrobial agents represent suitable alternatives to clinical preservatives in food industry to increase both safety and stability of aliments. Here, we focused on the enzyme D-amino acid oxidase (DAAO) from the yeast Rhodotorula gracilis, a well-studied protein for biotechnological use based on its stability, high activity, and easy recombinant production. DAAO catalyzes the O-2-dependent oxidative deamination of D-enantiomer of amino acids generating alpha -keto acids, ammonia, and hydrogen peroxide. DAAO shows antibacterial activity on both Gram-positive and Gram-negative bacteria in the presence of D-alanine when tested on plates and reduced by half their growth when tested on liquid cultures. Control experiments performed with alternative amino acid-specific flavoenzymes (able or not to generate H2O2 acting on amino acids), a DAAO inactive variant, catalase (H2O2 scavenger), and L-amino acids instead of D-alanine identified H2O2 as the antibacterial agent. DAAO showed a good ability to decrease the bacterial growth on various food stuffs: e.g., 10-fold less colonies were formed on grated cheese incubated for 16 h at 37 degrees C when a tiny amount (0.01 mg corresponding to 1.2 units) of DAAO was added. No exogenous D-amino acids were added since DAAO used the ones naturally occurring or the ones generated during ripening. Notably, simultaneously to H2O2 generation, DAAO also acts as O-2-scavenger thus further hampering food deterioration

Treatment of malignant hypercalcaemia with aminohexane bisphosphonate (neridronate).

Twenty patients with hypercalcaemia due to malignancy, which persisted following rehydration, were treated with the bisphosphonate, aminohexane bisphosphonate (AHBP), which is structurally similar to pamidronate. The treatment given was a single infusion of 125 mg of AHBP in 500 ml of normal saline infused over 4 h. Serum and urine biochemistry were measured before and after treatment. Acute toxicity was evaluated with particular attention to gastrointestinal symptoms, acute-phase reaction and change in renal function, as judged by serum creatinine. The infusion of AHBP induced a rapid fall apparent by day 3 (P < 0.001), with a nadir at day 7. The serum calcium remained lower at days 14 and 28 than at day 0, but the numbers followed up were low (n = 5 and n = 4). In all 20 patients there was a fall in serum calcium after treatment, and in 13 (65%) normocalcaemia was achieved. Failure to respond completely to AHBP appeared to be associated with a renal mechanism of hypercalcaemia. Treatment was associated with a significant decrease in fasting urinary calcium excretion (P < 0.05). There was no change in white cell count or renal function following AHBP and only two cases of mild pyrexia after infusion. We conclude that aminohexane bisphosphonate is an effective agent in the treatment of tumour-induced hypercalcaemia, with rapid onset of effect and low toxicity

Autosomal recessive cerebellar ataxias: a diagnostic classification approach according to ocular features.

Autosomal recessive cerebellar ataxias (ARCAs) are a heterogeneous group of neurodegenerative disorders affecting primarily the cerebellum and/or its afferent tracts, often accompanied by damage of other neurological or extra-neurological systems. Due to the overlap of clinical presentation among ARCAs and the variety of hereditary, acquired, and reversible etiologies that can determine cerebellar dysfunction, the differential diagnosis is challenging, but also urgent considering the ongoing development of promising target therapies. The examination of afferent and efferent visual system may provide neurophysiological and structural information related to cerebellar dysfunction and neurodegeneration thus allowing a possible diagnostic classification approach according to ocular features. While optic coherence tomography (OCT) is applied for the parametrization of the optic nerve and macular area, the eye movements analysis relies on a wide range of eye-tracker devices and the application of machine-learning techniques. We discuss the results of clinical and eye-tracking oculomotor examination, the OCT findings and some advancing of computer science in ARCAs thus providing evidence sustaining the identification of robust eye parameters as possible markers of ARCAs