Evidence of high production levels of thermostable dextrinizing and saccharogenic amylases by Aspergillus niveus

The aim of this work was to analyze the effect of several nutritional and environmental parameters on amylase production by a novel, isolated from the thermotolerant filamentous fungus Aspergillus niveus. This strain produced high levels of amylolytic activity in Khanna liquid medium supplemented with commercial starch, initial pH 6.5, under static conditions for 72 h. Among the tested carbon sources, milled corn, oatmeal, soluble potato starch and maisena were the best inducers of enzymatic secretion (220, 180, 170 and 150 U/mL), respectively. The main products of hydrolysis analyzed by thin layer chromatography were glucose, maltose and traces of maltooligosaccharides, suggesting the presence of α-amylase and glucoamylase activities in the crude extract. The optimal pH were 4.5 and 5.5 and the optimum temperature was 65°C. The enzymes were fully stable up to 1 h at 55°C. It was possible to verify the presence of three bands with amylolytic activity in non-denaturing polyacrylamide gel electrophoresis (PAGE). These aspects and other properties suggested that the amylases produced by A. niveus might be suitable for biotechnological applications.KKeywords: Starch, α-amylase, glucoamylase, Aspergillus niveus, submerged fermentation, thermostabilityAfrican Journal of Biotechnology Vol. 12(15), pp. 1874-188

Biotechnological Potential of Agro-Industrial Wastes as a Carbon Source to Thermostable Polygalacturonase Production in Aspergillus niveus

Agro-industrial wastes are mainly composed of complex polysaccharides that might serve as nutrients for microbial growth and production of enzymes. The aim of this work was to study polygalacturonase (PG) production by Aspergillus niveus cultured on liquid or solid media supplemented with agro-industrial wastes. Submerged fermentation (SbmF) was tested using Czapeck media supplemented with 28 different carbon sources. Among these, orange peel was the best PG inducer. On the other hand, for solid state fermentation (SSF), lemon peel was the best inducer. By comparing SbmF with SSF, both supplemented with lemon peel, it was observed that PG levels were 4.4-fold higher under SSF. Maximum PG activity was observed at 55°C and pH 4.0. The enzyme was stable at 60°C for 90 min and at pH 3.0–5.0. The properties of this enzyme, produced on inexpensive fermentation substrates, were interesting and suggested several biotechnological applications

Biotechnological potential of alternative carbon sources for production of pectinases by Rhizopus microsporus var. rhizopodiformis

Fungi collected from Brazilian soil and decomposing plants were screened for pectinase production. R. microsporus var. rhizopodiformis was the best producer and was selected to evaluate the pectic enzyme production under several nutritional and environmental conditions. The pectinase production was studied at 40ºC, under 28 carbon sources-supplemented medium. The inducer effect of several agro-industrial residues such as sugar cane bagasse, wheat flour and corncob on polygalacturonase (PG) activity was 4-, 3- and 2-fold higher than the control (pectin). In glucose-medium, a constitutive pectin lyase (PL) activity was detected. The results demonstrated that R. microsporus produced high levels of PG (57.7 U/mg) and PL (88.6 U/mg) in lemon peel-medium. PG had optimum temperature at 65 ºC and was totally stable at 55 ºC for 90 min. Half-life at 70 ºC was 68 min. These results suggested that the versatility of waste carbon sources utilization by R. microsporus, produce pectic enzymes, which could be useful to reduce production costs and environmental impacts related to the waste disposal.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)(CNPq) Conselho de Desenvolvimento Científico e Tecnológic

A thermostable xylanase from a new strain of Aspergillus fumigatus presents high ability to hydrolyze hemicellulose from corn straw / Uma xilanase termoestável de uma nova estirpe de Aspergillus fumigatus apresenta elevada capacidade de hidrolisar hemicelulose a partir de palha de milho

ABSTRACTIn order to optimize the production of xylanase from a new thermophilic strain of Aspergillus fumigatus (OI-1R-T), Plackett-Burman design (PBD) and central composite rotational design (CCRD) were performed. The response surface plots indicated a trend for increased xylanase biosynthesis with increasing concentrations of corn straw. The optimized xylanase activity was 530 U mL-1 in the presence of 6.5% (w/v) of the residual biomass, which was 11 times (1,157%) higher than that obtained with only the PBD (45.8 U mL-1). Interestingly, xylanase thermostability was maintained at 90% at 50 °C for 6 h. Enzymatic hydrolysis assays conducted for 96 h with 2 U mL-1 of xylanase and crude corn straw, pre-treated corn straw (hemicellulose) and xylan from beechwood, resulted in the net production of 3.89, 20.96 and 21.64 µmol mL-1of reducing sugars, respectively. Thus, A. fumigatus xylanase was equally able to hydrolyzes hemicellulose from corn straw and xylan from beechwood. The present data indicate that the xylanase activity of A. fumigatus could be applied to the production of low molecular weight sugars for use by pentose-fermenting yeast for the production of fuels and chemicals, among other products. 

Survival Analysis of Patients with Heart Failure: Implications of Time-Varying Regression Effects in Modeling Mortality

Background: Several models have been designed to predict survival of patients with heart failure. These, while available and widely used for both stratifying and deciding upon different treatment options on the individual level, have several limitations. Specifically, some clinical variables that may influence prognosis may have an influence that change over time. Statistical models that include such characteristic may help in evaluating prognosis. The aim of the present study was to analyze and quantify the impact of modeling heart failure survival allowing for covariates with time-varying effects known to be independent predictors of overall mortality in this clinical setting. Methodology: Survival data from an inception cohort of five hundred patients diagnosed with heart failure functional class III and IV between 2002 and 2004 and followed-up to 2006 were analyzed by using the proportional hazards Cox model and variations of the Cox's model and also of the Aalen's additive model. Principal Findings: One-hundred and eighty eight (188) patients died during follow-up. For patients under study, age, serum sodium, hemoglobin, serum creatinine, and left ventricular ejection fraction were significantly associated with mortality. Evidence of time-varying effect was suggested for the last three. Both high hemoglobin and high LV ejection fraction were associated with a reduced risk of dying with a stronger initial effect. High creatinine, associated with an increased risk of dying, also presented an initial stronger effect. The impact of age and sodium were constant over time. Conclusions: The current study points to the importance of evaluating covariates with time-varying effects in heart failure models. The analysis performed suggests that variations of Cox and Aalen models constitute a valuable tool for identifying these variables. The implementation of covariates with time-varying effects into heart failure prognostication models may reduce bias and increase the specificity of such models.CNPq Brazilian Foundation for Scientific and Technological DevelopmentCNPq - Brazilian Foundation for Scientific and Technological Development [150653/2008-5

Pharmacological Analyses of Protein Kinases Regulating Egg Maturation in Marine Nemertean Worms: A Review and Comparison with Mammalian Eggs

For development to proceed normally, animal eggs must undergo a maturation process that ultimately depends on phosphorylations of key regulatory proteins. To analyze the kinases that mediate these phosphorylations, eggs of marine nemertean worms have been treated with pharmacological modulators of intracellular signaling pathways and subsequently probed with immunoblots employing phospho-specific antibodies. This article both reviews such analyses and compares them with those conducted on mammals, while focusing on how egg maturation in nemerteans is affected by signaling pathways involving cAMP, mitogen-activated protein kinases, Src-family kinases, protein kinase C isotypes, AMP-activated kinase, and the Cdc2 kinase of maturation-promoting factor

A genetic investigation of sex bias in the prevalence of attention-deficit/hyperactivity disorder

Background Attention-deficit/hyperactivity disorder (ADHD) shows substantial heritability and is 2-7 times more common in males than females. We examined two putative genetic mechanisms underlying this sex bias: sex-specific heterogeneity and higher burden of risk in female cases. Methods We analyzed genome-wide autosomal common variants from the Psychiatric Genomics Consortium and iPSYCH Project (20,183 cases, 35,191 controls) and Swedish populationregister data (N=77,905 cases, N=1,874,637 population controls). Results Genetic correlation analyses using two methods suggested near complete sharing of common variant effects across sexes, with rg estimates close to 1. Analyses of population data, however, indicated that females with ADHD may be at especially high risk of certain comorbid developmental conditions (i.e. autism spectrum disorder and congenital malformations), potentially indicating some clinical and etiological heterogeneity. Polygenic risk score (PRS) analysis did not support a higher burden of ADHD common risk variants in female cases (OR=1.02 [0.98-1.06], p=0.28). In contrast, epidemiological sibling analyses revealed that the siblings of females with ADHD are at higher familial risk of ADHD than siblings of affected males (OR=1.14, [95% CI: 1.11-1.18], p=1.5E-15). Conclusions Overall, this study supports a greater familial burden of risk in females with ADHD and some clinical and etiological heterogeneity, based on epidemiological analyses. However, molecular genetic analyses suggest that autosomal common variants largely do not explain the sex bias in ADHD prevalence

Ação das enzimas celulase, invertase, pectinase e xilanase na produção de vinhos – uma revisão sistemática da literatura / Activity of celulase, invertase, pectinase and xylanase enzymes in wine production - a systematic literature review

O vinho é uma bebida popular no mundo todo e a prática de vinificação é uma técnica complexa de elevadas operações convenientes às particularidades da uva para a fabricação do produto desejado. A potencialização destas operações sucede-se por ações enzimáticas. Desta forma, essa revisão objetiva reunir evidências de estudos biotecnológicos que visam o uso das enzimas celulase, pectinase, invertase e xilanase durante o processamento de vinhos. Essas macromoléculas apresentam uma gama de aplicações industriais e agem em função de promover melhorias na produção de vinhos em etapas como: fermentação, maceração, estabilidade, clarificação e extração de compostos fenólicos. Além disso, quando atuam em conjunto, algumas enzimas podem ter seus efeitos biotecnológicos intensificados. Portanto, as enzimas estudadas proporcionam benefícios ao vinho, tais como: aumento da clarificação e do rendimento, maior liberação de compostos bioativos, potencializam a recuperação de fenóis e antocianinas, diminuição da acidez e melhora das propriedades organolépticas como textura, sabor e aroma