Heat Stress Modulates Brain Monoamines and Their Metabolites Production in Broiler Chickens Co-Infected with Clostridium perfringens Type A and Eimeria spp.

Heat stress has been related to the impairment of behavioral and immunological parameters in broiler chickens. However, the literature is not clear on the involvement of neuroimmune interactions in a heat stress situation associated with bacterial and parasitic infections. The present study evaluated the production of monoamines and their metabolites in brain regions (rostral pallium, hypothalamus, brain stem, and midbrain) in broiler chickens submitted to chronic heat stress and/or infection and co-infection with Eimeria spp. and Clostridium perfringens type A. The heat stress and avian necrotic enteritis (NE) modulated the neurochemical profile of monoamines in different areas of the central nervous system, in particular, those related to the activity of the hypothalamus-hypophysis-adrenal (HPA) axis that is responsible for sickness behavior. C. perfringens and/or Eimeria infection, heat stress increased 5-hydroxytryptamine (5-HT), 4,4 dihydroxyphenylacetic acid (DOPAC), and DOPAC/dopamine (DA) in the rostral pallium; 3-methoxy-4-hydroxyphenylethylene glycol (MHPG), homovanillic acid (HVA), HVA/DA, DOPAC/DA, and 5-hydroxyindoleacetic acid (5-HIAA)/5-HT in the hypothalamus; MHPG, 5-HIAA/5-HT, DOPAC/DA, and HVA/DA in the midbrain; and MHPG, DOPAC, HVA, HVA/DA, DOPAC/DA, and 5-HIAA/5-HT in the brainstem. Heat stress decreased noradrenaline + norepinephrine (NOR + AD) in all brain regions analyzed; 5-HT in the hypothalamus, midbrain, and brainstem; and DA in the midbrain. The results also showed the existence and activity of the brain-gut axis in broiler chickens. The brain neurochemical profile and corticosterone production are consistent with those observed in chronic stressed mammals, in animals with sickness behavior, and an overloading of the HPA axis

Structural basis for glucose tolerance in GH1 b-glucosidases

Submitted by Tatiana Souza ([email protected]) on 2014-10-24T14:05:46Z No. of bitstreams: 1 J. Biol. Chem.-1997-Nare-13883-91.pdf: 1511856 bytes, checksum: 1819e3063bfd29935a7afcb91b0aa294 (MD5)Approved for entry into archive by Tatiana Souza ([email protected]) on 2014-11-25T17:03:08Z (GMT) No. of bitstreams: 1 J. Biol. Chem.-1997-Nare-13883-91.pdf: 1511856 bytes, checksum: 1819e3063bfd29935a7afcb91b0aa294 (MD5)Made available in DSpace on 2014-11-25T17:03:08Z (GMT). No. of bitstreams: 1 J. Biol. Chem.-1997-Nare-13883-91.pdf: 1511856 bytes, checksum: 1819e3063bfd29935a7afcb91b0aa294 (MD5) Previous issue date: 2014Centro Nacional de Pesquisa em Energia e Materiais. Laboratório Nacional de Biociências. Campinas, SP, Brasil. Campinas, SP, Brasil.Centro Nacional de Pesquisa em Energia e Materiais. Laboratório Nacional de Biociências. Campinas, SP, Brasil. Campinas, SP, Brasil / Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.Universidade de São Paulo. Faculdade de Filosofia, Ciências e Letras. Departamento de Química. Ribeirão Preto, SP, Brasil.Universidade Estadual de Campinas. Instituto de Química. Departamento de Química Orgânica. Campinas, SP, Brasil.Universidade de São Paulo. Faculdade de Filosofia, Ciências e Letras. Departamento de Química. Ribeirão Preto, SP, Brasil / Centro Nacional de Pesquisa em Energia e Materiais. Laboratório Nacional de de Ciência e Tecnologia do Bioetanol. Campinas, SP, Brasil.Universidade de São Paulo. Faculdade de Filosofia, Ciências e Letras. Departamento de Química. Ribeirão Preto, SP, Brasil / Centro Nacional de Pesquisa em Energia e Materiais. Laboratório Nacional de de Ciência e Tecnologia do Bioetanol. Campinas, SP, Brasil.Universidade de São Paulo. Faculdade de Filosofia, Ciências e Letras. Departamento de Biologia. Ribeirão Preto, SP, Brasil.Universidade de São Paulo. Faculdade de Filosofia, Ciências e Letras. Departamento de Química. Ribeirão Preto, SP, Brasil.Centro Nacional de Pesquisa em Energia e Materiais. Laboratório Nacional de Biociências. Campinas, SP, Brasil. Campinas, SP, Brasil.Product inhibition of β-glucosidases (BGs) by glucose is considered to be a limiting step in enzymatic technologies for plant-biomass saccharification. Remarkably, some β-glucosidases belonging to the GH1 family exhibit unusual properties, being tolerant to, or even stimulated by, high glucose concentrations. However, the structural basis for the glucose tolerance and stimulation of BGs is still elusive. To address this issue, the first crystal structure of a fungal β-glucosidase stimulated by glucose was solved in native and glucose-complexed forms, revealing that the shape and electrostatic properties of the entrance to the active site, including the +2 subsite, determine glucose tolerance. The aromatic Trp168 and the aliphatic Leu173 are conserved in glucose-tolerant GH1 enzymes and contribute to relieving enzyme inhibition by imposing constraints at the +2 subsite that limit the access of glucose to the -1 subsite. The GH1 family β-glucosidases are tenfold to 1000-fold more glucose tolerant than GH3 BGs, and comparative structural analysis shows a clear correlation between active-site accessibility and glucose tolerance. The active site of GH1 BGs is located in a deep and narrow cavity, which is in contrast to the shallow pocket in the GH3 family BGs. These findings shed light on the molecular basis for glucose tolerance and indicate that GH1 BGs are more suitable than GH3 BGs for biotechnological applications involving plant cell-wall saccharification

Bioprospection and characterization of the amylolytic activity by filamentous fungi from Brazilian Atlantic Forest

<div><p>Abstract Filamentous fungi are widely diverse and ubiquitous organisms. Such biodiversity is barely known, making room for a great potential still to be discovered, especially in tropical environments - which are favorable to growth and species variety. Filamentous fungi are extensively applied to the production of industrial enzymes, such as the amylases. This class of enzymes acts in the hydrolysis of starch to glucose or maltooligosaccharides. In this work twenty-five filamentous fungi were isolated from samples of decomposing material collected in the Brazilian Atlantic Forest. The two best amylase producers were identified as Aspergillus brasiliensis and Rhizopus oryzae. Both are mesophilic, they grow well in organic nitrogen-rich media produce great amounts of glucoamylases. The enzymes of A. brasiliensis and R. oryzae are different, possibly because of their phylogenetical distance. The best amylase production of A. brasiliensis occurred during 120 hours with initial pH of 7.5; it had a better activity in the pH range of 3.5-5.0 and at 60-75°C. Both fungal glucoamylase had wide pH stability (3-8) and were activated by Mn2+. R. oryzae best production occurred in 96 hours and at pH 6.5. Its amylases had a greater activity in the pH range of 4.0-5.5 and temperature at 50-65ºC. The most significant difference between the enzymes produced by both fungi is the resistance to thermal denaturation: A. brasiliensis glucoamylase had a T50 of 60 minutes at 70ºC. The R. oryzae glucoamylase only had a residual activity when incubated at 50°C with a 12 min T50.</p></div

Co-cultivation of Aspergillus nidulans recombinant strains produces an enzymatic cocktail as alternative to alkaline sugarcane bagasse pretreatment

Plant materials represent a strategic energy source because they can give rise to sustainable biofuels through the fermentation of their carbohydrates. A clear example of a plant-derived biofuel resource is the sugar cane bagasse exhibiting 60 % - 80 % of fermentable sugars in its composition. However, the current methods of plant bioconversion employ severe and harmful chemical/physical pretreatments raising biofuel cost production and environmental degradation. Replacing these methods with co-cultivated enzymatic cocktails is an alternative. Here we propose a pretreatment for sugarcane bagasse using a multi-enzymatic cocktail from the co-cultivation of four Aspergillus nidulans recombinant strains. The co-cultivation resulted in the simultaneous production of GH51 arabinofuranosidase (AbfA), GH11 endo-1,4-xylanase (XlnA), GH43 endo-1,5-arabinanase (AbnA) and GH12 xyloglucan specific endo-β-1,4-glucanase (XegA). This core set of recombinant enzymes was more efficient than the alternative alkaline method in maintaining the cellulose integrity and exposing this cellulose to the following saccharification process. Thermogravimetric and differential thermal analysis revealed residual byproducts on the alkali pretreated biomass, which were not found in the enzymatic pretreatment. Therefore, the enzymatic pretreatment was residue-free and seemed to be more efficient than the applied alkaline method, which makes it suitable for bioethanol production