Xylanase and beta-Xylosidase Production by Aspergillus ochraceus: New Perspectives for the Application of Wheat Straw Autohydrolysis Liquor

The xylanase biosynthesis is induced by its substrate-xylan. The high xylan content in some wastes such as wheat residues (wheat bran and wheat straw) makes them accessible and cheap sources of inducers to be mainly applied in great volumes of fermentation, such as those of industrial bioreactors. Thus, in this work, the main proposal was incorporated in the nutrient medium wheat straw particles decomposed to soluble compounds (liquor) through treatment of lignocellulosic materials in autohydrolysis process, as a strategy to increase and undervalue xylanase production by Aspergillus ochraceus. The wheat straw autohydrolysis liquor produced in several conditions was used as a sole carbon source or with wheat bran. The best conditions for xylanase and beta-xylosidase production were observed when A. ochraceus was cultivated with 1% wheat bran added of 10% wheat straw liquor (produced after 15 min of hydrothermal treatment) as carbon source. This substrate was more favorable when compared with xylan, wheat bran, and wheat straw autohydrolysis liquor used separately. The application of this substrate mixture in a stirred tank bioreactor indicated the possibility of scaling up the process to commercial production.

Production of xylanase and beta-xylosidase from autohydrolysis liquor of corncob using two fungal strains

Agroindustrial residues are materials often rich in cellulose and hemicellulose. The use of these substrates for the microbial production of enzymes of industrial interest is mainly due to their high availability associated with their low cost. In this work, corncob (CCs) particles decomposed to soluble compounds (liquor) were incorporated in the microbial growth medium through autohydrolysis, as a strategy to increase and undervalue xylanase and beta-xylosidase production by Aspergillus terricola and Aspergillus ochraceus. The CCs autohydrolysis liquor produced at 200 A degrees C for 5, 15, 30 or 50 min was used as the sole carbon source or associated with untreated CC. The best condition for enzyme synthesis was observed with CCs submitted to 30 min of autohydrolysis. The enzymatic production with untreated CCs plus CC liquor was higher than with birchwood xylan for both microorganisms. A. terricola produced 750 total U of xylanase (144 h cultivation) and 30 total U of beta-xylosidase (96-168 h) with 0.75% untreated CCs and 6% CCs liquor, against 650 total U of xylanase and 2 total U of beta-xylosidase in xylan; A. ochraceus produced 605 total U of xylanase and 56 total U of beta-xylosidase (168 h cultivation) with 1% untreated CCs and 10% CCs liquor against 400 total U of xylanase and 38 total U of beta-xylosidase in xylan. These results indicate that the treatment of agroindustrial wastes through autohydrolysis can be a viable strategy in the production of high levels of xylanolytic enzymes.

Self-potential signals from an analog biogeobattery mode

A tank experiment was conducted to check if self-potential (SP) signals can be generated when buried organic matter is wire-connected to a near-surface, oxygen-rich, sediment layer. This experiment demonstrated that once wired, there was a flux of electrons (hence an electric current) between the lower and upper layers of the sandbox with the system responding as a large-scale microbial fuel cell (a type of bioelectrochemical system). An electric current was generated by this process in the wire and the SP method was used to monitor the associated electric potential distribution at the top of the tank.. The electric field was controlled by the flux of electrons through the wire, the oxidation of the organic matter, the reduction of oxygen used as a terminal electron acceptor, and the distribution of the DC resistivity in the tank. The current density through the wire was limited by the availability of oxygen and not by the oxidation of the organic matter. This laboratory experiment incorporated key elements of the biogeobattery observed in some organic-rich contaminant plumes. This analogy includes the generation of SP signals associated with a flux of electrons, the capacity of buried organic matter in sustaining anodic reactions, network resistance connecting terminal redox reactions spatially separated in space, and the existence of anodic secondary coupled reactions. A resistivity tomogram of the tank, after almost a year in operation, suggests that oxidative processes triggered by this geobattery can be imaged with this method to determine the radius of influence of the bioelectrochemical system.

Novel insights into the genomic basis of citrus canker based on the genome sequences of two strains of Xanthomonas fuscans subsp. aurantifolii

Abstract Background Citrus canker is a disease that has severe economic impact on the citrus industry worldwide. There are three types of canker, called A, B, and C. The three types have different phenotypes and affect different citrus species. The causative agent for type A is Xanthomonas citri subsp. citri, whose genome sequence was made available in 2002. Xanthomonas fuscans subsp. aurantifolii strain B causes canker B and Xanthomonas fuscans subsp. aurantifolii strain C causes canker C. Results We have sequenced the genomes of strains B and C to draft status. We have compared their genomic content to X. citri subsp. citri and to other Xanthomonas genomes, with special emphasis on type III secreted effector repertoires. In addition to pthA, already known to be present in all three citrus canker strains, two additional effector genes, xopE3 and xopAI, are also present in all three strains and are both located on the same putative genomic island. These two effector genes, along with one other effector-like gene in the same region, are thus good candidates for being pathogenicity factors on citrus. Numerous gene content differences also exist between the three cankers strains, which can be correlated with their different virulence and host range. Particular attention was placed on the analysis of genes involved in biofilm formation and quorum sensing, type IV secretion, flagellum synthesis and motility, lipopolysacharide synthesis, and on the gene xacPNP, which codes for a natriuretic protein. Conclusion We have uncovered numerous commonalities and differences in gene content between the genomes of the pathogenic agents causing citrus canker A, B, and C and other Xanthomonas genomes. Molecular genetics can now be employed to determine the role of these genes in plant-microbe interactions. The gained knowledge will be instrumental for improving citrus canker control.

Non-HFE hemochromatosis

Hereditary hemochromatosis (HH) is an autosomal recessive disorder classically related to HFE mutations. However, since 1996, it is known that HFE mutations explain about 80% of HH cases, with the remaining around 20% denominated non-HFE hemochromatosis. Nowadays, four main genes are implicated in the pathophysiology of clinical syndromes classified as non-HFE hemochromatosis: hemojuvelin (HJV, type 2Ajuvenile HH), hepcidin (HAMP, type 2B juvenile HH), transferrin receptor 2 (TFR2, type 3 HH) and ferroportin (SLC40A1, type 4 HH). The aim of this review is to explore molecular, clinical and management aspects of non-HFE hemochromatosis.

Angiotensin II type 1 receptor blockade partially attenuates hypoxia-induced pulmonary hypertension in newborn piglets: relationship with the nitrergic system

The objective of this study was to observe possible interactions between the renin-angiotensin and nitrergic systems in chronic hypoxia-induced pulmonary hypertension in newborn piglets. Thirteen chronically instrumented newborn piglets (6.3 +/- 0.9 days; 2369 +/- 491 g) were randomly assigned to receive saline (placebo, P) or the AT(1) receptor (AT(1)-R) blocker L-158,809 (L) during 6 days of hypoxia (FiO(2) = 0.12). During hypoxia, pulmonary arterial pressure (Ppa; P < 0.0001), pulmonary vascular resistance (PVR; P < 0.02) and the pulmonary to systemic vascular resistance ratio (PVR/SVR; P < 0.05) were significantly attenuated in the L (N = 7) group compared to the P group (N = 6). Western blot analysis of lung proteins showed a significant decrease of endothelial NOS (eNOS) in both P and L animals, and of AT(1)-R in P animals during hypoxia compared to normoxic animals (C group, N = 5; P < 0.01 for all groups). AT(1)-R tended to decrease in L animals. Inducible NOS (iNOS) did not differ among P, L, and C animals and iNOS immunohistochemical staining in macrophages was significantly more intense in L than in P animals (P < 0.01). The vascular endothelium showed moderate or strong eNOS and AT(1)-R staining. Macrophages and pneumocytes showed moderate or strong iNOS and AT(1)-R staining, but C animals showed weak iNOS and AT(1)-R staining. Macrophages of L and P animals showed moderate and weak AT(2)-R staining, respectively, but the endothelium of all groups only showed weak staining. In conclusion, pulmonary hypertension induced by chronic hypoxia in newborn piglets is partially attenuated by AT(1)-R blockade. We suggest that AT(1)-R blockade might act through AT(2)-R and/or Mas receptors and the nitrergic system in the lungs of hypoxemic newborn piglets.

Cost-effectiveness and budget impact of saxagliptine as additional therapy to metformin for the treatment of diabetes mellitus type 2 in the Brazilian private health system

Cost-effectiveness and budget impact of saxagliptine as additional therapy to metformin for the treatment of diabetes mellitus type 2 in the Brazilian private health system Objectives: To compare costs and clinical benefits of three additional therapies to metformin (MF) for patients with diabetes mellitus type 2 (DM2). Methods: A discrete event simulation model seas built to estimate the cost-utility ratio (cost per quality-adjusted life years [QALY)) of saxagliptine as an additional therapy to MF when compared to rosiglitazone or pioglitazone. A budget impact model (BIM) was built to simulate the economic impact of saxagliptine use in the context of the Brazilian private health system. Results: The acquiring medication costs for the hypothetical patient group analyzed in a time frame of three years, were R$ 10,850,185, R$ 14,836,265 and R$ 14,679,099 for saxagliptine, pioglitazone and rosiglitazone, respectively. Saxagliptine showed lower costs and greater effectiveness in both comparisons, with projected savings for the first three years of R$ 3,874 and R$ 3,996, respectively. The BIM estimated cumulative savings of R$ 417,958 with the repayment of saxagliptine in three years from the perspective of a health plan with 1,000,000 covered individuals. Conclusion: From the perspective of private paying source, the projection is that adding saxagliptine with MF save costs when compared with the addition of rosiglitazone or pioglitazone in patients with DM2 that have not reached the HbA1c goal with metformin monotherapy. The BIM of including saxagliptine in the reimbursement lists of health plans indicated significant savings on the three-year horizon.

Structure and Ionic Conductivity in the Mixed-Network Former Chalcogenide Glass System [Na2S](2/3)[(B2S3)(x)(P2S5)(1-x)](1/3)

Glasses in the system [Na2S](2/3)[(B2S3)(x)(P2S5)(1-x)](1/3) (0.0 <= x <= 1.0) were prepared by the melt quenching technique, and their properties were characterized by thermal analysis and impedance spectroscopy. Their atomic-level structures were comprehensively characterized by Raman spectroscopy and B-11, P-31, and Na-23 high resolution solid state magic-angle spinning (MAS) NMR techniques. P-31 MAS NMR peak assignments were made by the presence or absence of homonuclear indirect P-31-P-31 spin-spin interactions as detected using homonuclear J-resolved and refocused INADEQUATE techniques. The extent of B-S-P connectivity in the glassy network was quantified by P-31{B-11} and B-11{P-31} rotational echo double resonance spectroscopy. The results clearly illustrate that the network modifier alkali sulfide, Na2S, is not proportionally shared between the two network former components, B and P. Rather, the thiophosphate (P) component tends to attract a larger concentration of network modifier species than predicted by the bulk composition, and this results in the conversion of P2S74-, pyrothiophosphate, Na/P = 2:1, units into PS43-, orthothiophosphate, Na/P = 3:1, groups. Charge balance is maintained by increasing the net degree of polymerization of the thioborate (B) units through the formation of covalent bridging sulfur (BS) units, B S B. Detailed inspection of the B-11 MAS NMR spectra reveals that multiple thioborate units are formed, ranging from neutral BS3/2 groups all the way to the fully depolymerized orthothioborate (BS33-) species. On the basis of these results, a comprehensive and quantitative structural model is developed for these glasses, on the basis of which the compositional trends in the glass transition temperatures (T-g) and ionic conductivities can be rationalized. Up to x = 0.4, the dominant process can be described in a simplified way by the net reaction equation P-1 + B-1 reversible arrow P-0 + B-4, where the superscripts denote the number of BS atoms for the respective network former species. Above x = 0.4, all of the thiophosphate units are of the P-0 type and both pyro-(B-1) and orthothioborate (B-0) species make increasing contributions to the network structure with increasing x. In sharp contrast to the situation in sodium borophosphate glasses, four-coordinated thioborate species are generally less abundant and heteroatomic B-S-P linkages appear to not exist. On the basis of this structural information, compositional trends in the ionic conductivities are discussed in relation to the nature of the charge-compensating anionic species and the spatial distribution of the charge carriers.