Co-cultivation of Thermoanaerobacter strains with a methanogenic partner enhances glycerol conversion

Glycerol-rich waste streams produced by the biodiesel, bioethanol and oleochemical industries can be treated and valorized by anaerobic microbial communities to produce methane. As current knowledge of the microorganisms involved in thermophilic glycerol conversion to methane is scarce, thermophilic glycerol-degrading methanogenic communities were enriched. A co-culture of Thermoanaerobacter and Methanothermobacter species was obtained, pointing to a non-obligately syntrophic glycerol degradation. This hypothesis was further studied by incubating Thermoanaerobacter brockii subsp. finnii and T. wiegelii with glycerol (10 mM) in pure culture and with different hydrogenotrophic methanogens. The presence of the methanogen accelerated glycerol fermentation by the two Thermoanaerobacter strains up to 3.3 mM day⁻¹, corresponding to 12 times higher volumetric glycerol depletion rates in the methanogenic co-cultures than in the pure bacterial cultures. The catabolic pathways of glycerol conversion were identified by genome analysis of the two Thermoanaerobacter strains. NADH and reduced ferredoxin formed in the pathway are linked to proton reduction, which becomes thermodynamically favourable when the hydrogen partial pressure is kept low by the hydrogenotrophic methanogenic partner.     

Novel exon nucleotide deletion causes adrenoleukodystrophy in a Brazilian family

Adrenoleukodystrophy is a neurodegenerative X-linked recessive disorder. It is characterized by abnormal function of peroxisomes, which leads to an accumulation of very long-chain fatty acids in plasma and tissues, especially in the cortex of adrenal glands and white matter of the central nervous system, causing demyelinating disease and adrenocortical insufficiency (Addison's disease). It is caused by a mutation in the ABCD1 gene (ATP-binding cassette, subfamily D, member 1), which encodes the protein adrenoleukodystrophy that is involved in the transport of fatty acids into the peroxisome for degradation. Variable expression has been recognized in families of patients who have this disease. A Brazilian family from Minas Gerais State, Brazil, was studied. The proband is an adult living in Minas Gerais State, Brazil; he had adrenomyeloneuropathy, adrenocortical insufficiency and a stable cerebral form. DNA was extracted from a blood sample and was sequenced to identify the mutation. The patient's exons were cloned for confirmation. A new mutation was found in exon 5 of the ABCD1 gene (c.1430delA), as well as a single-nucleotide polymorphism in exon 6. The mutation causes a frame shift, resulting in a truncated protein with almost total absence of the ATP binding domain.     

Comparative analysis of gonadal morphology in six fish species of the Incertae Sedis genera in Characidae of occurrence in the São Francisco River Basin,Brazil

Martins, Y.S., Arantes, F.P., Sato, Y., dos Santos, J.E., Rizzo, E. and Bazzoli, N. 2012. Comparative analysis of gonadal morphology in six fish species of the Incertae Sedis genera in Characidae of occurrence in the São Francisco River Basin, Brazil. —Acta Zoologica (Stockholm) 93 : 48–56. This study presents a comparative analysis aiming to show the remarkable differences found in gonad morphology between six fish species from the genera Incertae Sedis in the Characidae family. Maturing ovaries of Astyanax fasciatus presented grayish color whilst the other species’ were yellowish in color. The cortical alveoli of the analyzed species are small (5.20 ± 1.44–8.28 ± 2.02 μm) and are formed by various discontinuous layers of vesicles except in the Bryconops affinis, where they are large (12.87 ± 2.41 μm) and form various continuous layers of vesicles. The pellucid zone is thin and varies from 2.44 ± 0.90 to 5.79 ± 1.90 μm and is thickest in B. affinis (10.57 ± 2.08 μm). Folds in the pellucid zone were observed in Astyanax bimaculatus, A. fasciatus, Hemigrammus marginatus, and Moenkhausia costae. The follicular cells of B. affinis are columnar (28.19 ± 13.71 μm), while they are squamous in other species (1.52 ± 0.64–2.12 ± 0.78 μm). This study showed that the morphologic and biometric characteristics of the B. affinis vitellogenic oocytes are statistically different than the analyzed other ones Incertae Sedis of the Characidae family. In advanced maturing testis of A. bimaculatus and A. fasciatus, the spermatozoa were embedded in acidophilic secretion which was gradually reabsorbed in the seminiferous tubules when males were partially spent.     

The adsorption and enzyme activity profiles of specific Trichoderma reesei cellulase/xylanase components when hydrolyzing steam pretreated corn stover

Recycling of enzymes during biomass conversion is one potential strategy to reduce the cost of the hydrolysis step of cellulosic ethanol production. Devising an efficient enzyme recycling strategy requires a good understanding of how the enzymes adsorb, distribute, and interact with the substrate during hydrolysis. We investigated the interaction of individual Trichoderma reesei enzymes present in a commercial cellulase mixture during the hydrolysis of steam-pretreated corn stover (SPCS). The enzyme profiles were followed using zymograms, gel electrophoresis, enzyme activity assays and mass spectrometry. The adsorption and activity profiles of 6 specific enzymes Cel7A (CBH I), Cel7B (EG I), Cel5A (EG II), Xyn 10 (endo-1,4-β-xylanase III), Xyn 11 (endo-xylanase II), and β-glucosidase were characterized. Initially, each of the enzymes rapidly adsorbed onto the SPCS. However, this was followed by partial desorption to an adsorption equilibrium where the Cel7A, Cel7B, Xyn 10, and β-glucosidase were partially adsorbed to the SPCS and also found free in solution throughout the course of hydrolysis. In contrast, the Cel5A and Xyn 11 components remained primarily free in the supernatant. The Cel7A component also exhibited a partial desorption when the rate of hydrolysis leveled off as evidenced by MUC zymogram and SDS-PAGE. Those cellulase components that did not bind to the substrate were generally less stable and lost their activities within the first 24h when compared to enzymes that were distributed in both the liquid and solid phases. Therefore, to ensure maximum enzyme activity recovery, enzyme recycling seems to be most effective when short-term rounds of hydrolysis are combined with the recovery of enzymes from both the liquid and the solid phases and potentially enzyme supplementation to replenish lost activity.     

Carbon source pulsed feeding to attain high yield and high productivity in poly(3-hydroxybutyrate) (PHB) production from soybean oil using <Emphasis Type="Italic">Cupriavidus necator</Emphasis>

Poly(3-hydroxybutyrate) (PHB) biosynthesis from soybean oil by Cupriavidus necator was studied using a bench scale bioreactor. The highest cell concentration (83 g l⁻¹) was achieved using soybean oil at 40 g l⁻¹ and a pulse of the same concentration. The PHB content was 81% (w/w), PHB productivity was 2.5 g l⁻¹ h⁻¹, and the calculated Y_p/s value was 0.85 g g⁻¹. Growth limitation and the onset of PHB biosynthesis took place due to exhaustion of P, and probably also Cu, Ca, and Fe.     

Environmental Mapping of Paracoccidioides spp. in Brazil Reveals New Clues into Genetic Diversity,Biogeography and Wild Host Association

BackgroundParacoccidioides brasiliensis and Paracoccidioides lutzii are the etiological agents of Paracoccidioidomycosis (PCM), and are easily isolated from human patients. However, due to human migration and a long latency period, clinical isolates do not reflect the spatial distribution of these pathogens. Molecular detection of P. brasiliensis and P. lutzii from soil, as well as their isolation from wild animals such as armadillos, are important for monitoring their environmental and geographical distribution. This study aimed to detect and, for the first time, evaluate the genetic diversity of P. brasiliensis and P. lutzii for Paracoccidioidomycosis in endemic and non-endemic areas of the environment, by using Nested PCR and in situ hybridization techniques.Conclusions/SignificanceData may reflect the actual occurrence of Paracoccidioides species in their saprobic habitat, despite their absence/non-detection in seven armadillos evaluated in regions with high prevalence of PCM infection by P. lutzii. These results may indicate a possible ecological difference between P. brasiliensis and P. lutzii concerning their wild hosts.     

Scorpion venom increases mRNA expression of lung cytokines

Previous studies have demonstrated that scorpion toxins increase the serum levels of IL-1, IL-6, INF-gamma, and GM-CSF in patients with severe shock and pulmonary edema. Moreover, it has been shown that experimental models of scorpion envenomation presented an increase in serum levels of IL-1, IL-6, IFN-gamma and nitric oxide. Thus, it is possible that the cytokine release may contribute to the onset and maintenance of the pulmonary edema induced by scorpion venom. This study was designed to investigate whether inflammatory and non-inflammatory cytokines, contribute to the pulmonary injury induced by infusion of Tityus serrulatus scorpion toxin in rats. We show that scorpion venom not only increases the expression of mRNA pulmonary inflammatory cytokines but also non-inflammatory cytokines as well. Moreover, the expression of IL-1alpha, IL-1beta and IL-6 mRNA was shown to be higher among the remaining detectable cytokines. The findings of this study provide additional insight towards the understanding of the pathophysiology of the pulmonary edema induced by scorpion venom. The increased level of pulmonary cytokines observed during the pulmonary edema may be responsible for the exacerbation and maintenance of the inflammatory response to scorpion venom in the lungs.     

Trypanosoma cruzi: treatment with the iron chelator desferrioxamine reduces parasitemia and mortality in experimentally infected mice

The effects of prolonged treatment with iron chelator (desferrioxamine) on the development of infection in mice inoculated with Y Trypanosoma cruzi were determined. Infected/treated mice presented lower levels of parasitemia and reduced mortality rate compared with infected/non-treated animals. The five out of twenty infected/treated mice that survived the acute phase of infection showed negative hemoculture and positive ELISA in the acute and chronic phases and positive PCR in the acute phase: in the chronic phase, three of the animals presented negative PCR. The single surviving infected/non-treated animal exhibited positive hemoculture, PCR and ELISA in both phases of infection. Infected groups presented lower levels of iron in the liver compared with treated/non-infected or non-treated/non-infected animals. The serum iron levels of the infected/non-treated group were higher on the 21st day post-infection in comparison with control and infected/treated groups. These results suggest that decrease of iron in the host leads to T. cruzi infection attenuation.