Comparing lactate and glycerol as a single-electron donor for sulfate reduction in fluidized bed reactors.

Among the greatest challenges to the full implementation of biological sulfate reduction are the cost and availability of the electron source. With the development of the biofuel industry, new organic substrates have become available. Therefore, this work sought to compare the performance of a sulfidogenic process utilizing either lactate or glycerol as the substrate for sulfate-reducing bacteria (SRB) growth. Although sulfate reduction is energetically more favorable with lactate, glycerol is a less expensive alternative because excess production is forecasted with the worldwide development of the biodiesel industry. Continuous experiments were performed in a fluidized bed (FB) reactor containing activated carbon as a carrier for a mixed bacterial population composed of sulfate-reducing and fermentative bacteria. During the lactate-fed phases, incomplete oxidation of lactate to acetate by SRB was the dominant metabolic pathway resulting in as much as 90 % sulfate reduction and high acetate concentrations (2.7 g L-1). Conversely, in the glycerol-fed phases, glycerol degradation resulted from syntrophic cooperation between sulfate-reducing and fermentative bacteria that produce butyrate along with acetate (1.0 g L-1) as oxidation products. To our knowledge, this is the first report of butyrate formation during sulfate reduction in a glycerol-fed continuousflow reactor. Sulfate concentrations were reduced by about 90 % (from 2,000 to 100–300 mg L-1) when glycerol was being fed to the reactor. Since the FB reactor was able to stand a change from lactate to glycerol, this reactor is recommended as the preferred option should glycerol be selected as a cost-effective alternative to lactate for continuous sulfate reduction

Schistosoma mansoni : functional proteasomes are required for development in the vertebrate host.

Proteasomes are multi-subunit proteases involved in several mechanisms and thought to contribute to the regulation of cellular homeostasis. Here, we report for the Wrst time biochemical evidence for the existence of a ubiquitin–proteasome proteolytic pathway in this parasite. Proteasomes from both cercariae and adult worms exhibited a high preference for hydrolysis of the substrate Suc- LLVY-AMC, although in the cercariae extract the rate of hydrolysis was 50% lower when compared to adult worms extracts. The same diVerence in proteasome activities was observed when endogenous proteins were broken down in the presence of ATP and ubiquitin. Additionally, accumulation of high molecular weight conjugates was observed when cercariae were pre-incubated with proteasome inhibitors. Finally, we present evidence that during experimental schistosomiasis, proteasome inhibitors were able to reduce the number of lung stage schistosomula, reduce the worm burden and consequently decrease the egg output in infected mice

Characterisation of the COP9 signalosome in Schistosoma mansoni parasites.

The COP9 signalosome (CSN) is an eight-subunit complex found in all eukaryotes and shares structural features with both the 26S proteasome ‘lid’ and translation factor eIF3. Recent data have demonstrated that the CSN is a regulator of the ubiquitin (Ub) proteasome system (UPS). CSN controls substrate ubiquitination by cullin-RING Ub ligases, a step which determines substrate specificity of the UPS. Here, we reconstructed the CSN complex in Schistosoma mansoni and identified eight homologous components. Among these homologues, five subunits were predicted with their full-length sequences. Phylogenetic analysis confirmed the evolutionary conservation and the architecture of CSN, as well as the 26S proteasome ‘lid’. We performed quantitative reverse transcrip tion-polymerase chain reaction to detect the expression of the SmCSN transcripts. The Smcsn1, Smcsn2, Smcsn3, Smcsn4, Smcsn5, Smcsn6, Smcsn7 and Smcsn8 genes were upregulated in adult worms compared to cercariae, and the expression levels were similar to that of in vitro cultivated schistosomula. Taken together, these results suggest that the CSN complex may be important during cercariae, schistosome and adult worm development and might explain, at least in part, the differences among UPSs during the parasite life cycle

Neuropeptide Y in the medial basal hypothalamus and medial preoptic area during the induction of LH surge may be controlled by locus coeruleus.

The multiple control of gonadotropin releasing hormone (GnRH)/luteinizing hormone (LH) secretion involves locus coeruleus (LC) and neuropeptide Y (NPY). The objective of the present study was to analyze the possible contribution of the LC to the control of NPY activity in the medial basal hypothalamus (MBH) and medial preoptic area (MPOA) during the LH surge induced by estrogen (E2) and progesterone (P4). Ovariectomized adult Wistar rats were submitted to the hormone replacement and to the LC bilateral lesion (lesioned groups) or sham surgery (control groups). On the day of the experiment the rats were decapitated at 11:00, 13:00, 15:00 and 17:00 h for plasma and brain collection. Plasma LH was determined by radioimmunoassay. MBH and MPOA were microdissected for the measurement of NPY by enzyme immunoassay. NPY mRNA levels in MBH were assessed by the ribonuclease protection assay. The results showed that LC lesion: decreased the plasma LH; increased the content of NPY in the MBH and reduced the increase of NPY content in the MPOA during afternoon in which LH surge was induced. The increased NPY content in MBH was not associated with an increase of the respective mRNA content, suggesting the action of postranscriptional and/or posttranslational mechanisms. In conclusion, the NPY activity in the MPOA on LH surge induced by estrogen and progesterone could be controlled by LC through two ways, at least: one direct way, by the release of NPY from LC neurons terminals that innervate the MPOA and they release NA and NPY; one indirect way, by the control of release but not synthesis of NPY from neurons in the MBH which innervate the MPOA

Implications of volatile fatty acid profile on the metabolic pathway during continuous sulfate reduction.

Volatile fatty acid (VFA) profile is an important parameter in anaerobic reactors because it enables the assessment of metabolic pathways. Volatile fatty acids were monitored during sulfate reduction in a UASB (upflow anaerobic sludge blanket) reactor treating 2 g/L sulfate concentration and with the organic loading increasing from 3.5 kg COD/m3 d to 5.9 kg COD/m3 d, for a 1-day residence time. In the absence of recirculation, the best outcome (65% reduction) was noticed with the lowest organic loading (3.55 kg/m3 d). When recirculation was applied, sulfate reduction yields increased to 89%, corresponding to a sulfate removal rate of 1.94 kg SO4 2_/m3 d. The reactor performance was discussed in relation to microbial diversity and metabolic pathways. At high organic loading, two metabolic pathways account for lactate degradation: (i) lactate is oxidized to acetate and carbon dioxide by the incomplete-oxidizer SRB (sulfate-reducing bacteria) Desulfomonas, Desulfovibrio, Desulfolobus, Desulfobulbus and Desulfotomaculum spp.; (ii) lactate is converted to acetate by fermenting bacteria such as Clostridium sp. High propionate concentrations imply that there are low sulfate reduction efficiencies

Computational identification and evolutionary relationships of the MicroRNA gene cluster miR-71/2 in protostomes.

MicroRNAs (miRNAs) are small noncoding RNA molecules which are processed into *20–24 nt molecules that can regulate the gene expression posttranscriptionally. MiRNA gene clusters have been identified in a range of species, where in miRNAs are often processed from polycistronic transcripts. In this study, a computational approach is used to investigate the extent of evolutionary conservation of the miR-71/2 cluster in animals, and to identify novel miRNAs in the miRNA cluster miR-71/2. The miR-71/2 cluster, consisting of copies of the miR-71 and miR-2 (including miR-13) families, was found to be Protostome-specific. Although, this cluster is highly conserved across the Protostomia, the miR-2 family is completely absent from the Deuterostomia species, while miR-71 is absent from the Vertebrata and Urochordata. The evolutionary conservation and clustering propensity of the miR-71/2 family across the Protostomes could indicate the common functional roles across the member species of the Protostomia

Bowman-Birk inhibitors, proteasome peptidase activities and colorectal pre neoplasias induced by 1,2-dimethylhydrazine in Swiss mice.

Bowman-Birk inhibitors (BBIs) are protein molecules containing two inhibitory domains for enzymes similar to trypsin and chymotrypsin. Interest in these inhibitors arose from their properties against the cancer chemically induced by 1,2-dimethylhydrazine (DMH). In this study the effect of two BBI preparations (from Glycine max and Macrotyloma axillare) were evaluated for the prevention of colorectal neoplasia induced by intraperitoneal injections of DMH, given at a dose of 30 mg/kg, during 12 weeks. Mice treated with DMH presented histopathological alterations consistent with tumor development, augmented CD44 expression and increased proteasome peptidase activities. Lysosomal fractions, obtained from the intestines, were chromatographed in a Sepharose-BBI column and increased activity for trypsin and chymotrypsin-like proteases recovered from DMH-treated animals. In parallel, mice treated for eight weeks with BBIs showed a decrease in the chymotrypsin and trypsin-like proteasome activities compared to animals fed on normal diet. For the groups receiving simultaneous treatment with DMH and BBIs, dysplasic lesions were not observed and proteasome peptidase activities were similar to the control group after the 24th week. These results suggest that the mechanism by which BBIs could prevent the appearance of pre neoplastic lesions is associated with inhibition of both the lysosomal and proteasome- dependent proteolytic pathways

Endurance training blocks uncoupling protein 1 up-regulation in brown adipose tissue while increasing uncoupling protein 3 in the muscle tissue of rats fed with a high-sugar diet.

The mitochondrial uncoupling proteins (UCPs) of interscapular brown adipose tissue (iBAT) and of muscles play important roles in energy balance. For instance, the expression of UCP1 and UCP3 are modulated by free fatty acid gradients induced by high-sugar diets and acute exercise that is dependent on sympathetic stimulation. However, the effects of endurance training in animals fed with high-sugar diets are unknown. This study aims to evaluate the long-term effects of diet and exercise on UCP1 and UCP3 levels and energy balance efficiency. Rats fed with standard or high-sugar (HSD) diets were simultaneously subjected to running training over an 8-week period. After the training period, the rats were decapitated, and the iBAT and gastrocnemius muscle tissues were removed for evaluation of the β3-receptor, Ucp1, and Ucp3 mRNA and protein expression, which were analyzed by quantitative reverse transcriptase polymerase chain reaction and Western blot, respectively. Groups fed with an HSD displayed a higher adiposity index and iBAT weight (P < .05), whereas exhibited an up-regulation of Ucp1 mRNA and protein levels (P < .05). Training increased β3-receptor mRNA in iBAT and reduced the Ucp3 mRNA in muscle tissues. In association with an HSD, training restored the increasing β3-receptor mRNA and greatly up-regulated the levels of Ucp3 mRNA. Therefore, training blocked the HSD-induced up-regulation of UCP1 expression in iBAT, whereas it up-regulated the expression of Ucp3 mRNA in muscle. These results suggest that training enhances the relationship between Ucp1/Ucp3 mRNA levels, which could result in higher energy efficiency, but not when HSDinduced elevated sympathetic activity is maintained

Endurance training increases leptin expression in the retroperitoneal adipose tissue of rats fed with a high-sugar diet.

The presence of leptin receptors in white adipose tissue (WAT) suggests a type of peripheral control during the development of obesity and other metabolic disorders. Both diet composition and exercise influence serum leptin; however, the effect of their combination on long-term WAT leptin metabolism is unknown. In this study, rats fed with standard or high-sugar diets (HSD) were simultaneously subjected to running training for 4- and 8-week periods, and the retroperitoneal WAT (rWAT) was evaluated for adipocyte cell size, lipid and catecholamine content, Lep, OB-Rb and Ucp2 mRNA transcription levels, and circulating leptin and non-esterified fatty acids (NEFA). The HSD groups displayed a higher adiposity index and rWAT weight, Lep mRNA and protein upregulation, and a period-dependent effect on OB-Rb mRNA expression. Exercise decreased serum leptin and upregulated the OB-Rb mRNA levels. However, in rats fed with an HSD, the increase in OB-Rb mRNA and reduction in catecholamine levels resulted in a high level of adiposity and hyperleptinemia. The combination of training and an HSD decreases the NEFA levels and upregulating the Ucp2 mRNA expression in the 4-week period, while downregulating the Ucp2 mRNA expression in the 8-week period without changing the NEFA levels. Our results suggest that an HSD induces an increase in leptin expression in rWAT, while reducing adipocytes via leptin-mediated lipolysis after an 8-week period. In exercised rats fed an HSD, TAG synthesis and storage overlaps with lipolysis, promoting fat store development and Lep mRNA and plasma protein upregulation in adult rats

The 20S proteasome of Schistosoma mansoni : a proteomic analysis.

Proteasomes are molecular machines found in virtually all cells that provide one of the mechanisms for protein turnover. We have analysed the 20S proteasome of Schistosoma mansoni, the first multimeric complex isolated from this helminth parasite. Three chromatographic steps were employed to yield a highly homogeneous preparation. 2-DE of the purified complex revealed 58 spots, of which 46 could be assigned either an a or a b proteasome signature by MS. Most of the 14 transcripts (7a and 7b) encoded by the parasite genome were represented by multiple spots and we suggest that this diversity is due to PTMs of subunits. For most of the isoforms, variations in pI predominated although alterations in mass were also observed. 2-DE separations of extracts from infective cercariae and blood-dwelling adult worms probed by Western blotting, using a human anti-a subunit antibody, revealed different patterns of reactivity, most probably in a3 and a6 subunits, on the basis of sequence conservation. This difference was rapidly lost following transformation of the cercaria to the skin schistosomulum stage, suggesting that changes in the proteasome structure, likely caused by the introduction of a new set of PTMs, precede remodelling of the parasite body prior to intravascular migration