Power consumption evaluation of different fed-batch strategies for enzymatic hydrolysis of sugarcane bagasse

The minimization of costs in the distillation step of lignocellulosic ethanol production requires the use of a high solids loading during the enzymatic hydrolysis to obtain a more concentrated glucose liquor. However, this increase in biomass can lead to problems including increased mass and heat transfer resistance, decreased cellulose conversion, and increased apparent viscosity with the associated increase in power consumption. The use of fed-batch operation offers a promising way to circumvent these problems. In this study, one batch and four fed-batch strategies for solids and/or enzyme feeding during the enzymatic hydrolysis of sugarcane bagasse were evaluated. Determinations of glucose concentration, power consumption, and apparent viscosity were made throughout the experiments, and the different strategies were compared in terms of energy efficiency (mass of glucose produced according to the energy consumed). The best energy efficiency was obtained for the strategy in which substrate and enzyme were added simultaneously (0.35 kg_glucose kWh^?1). This value was 52 % higher than obtained in batch operation.     

Life span and reproductive cost explain interspecific variation in the optimal onset of reproduction

Fitness can be profoundly influenced by the age at first reproduction (AFR), but to date the AFR–fitness relationship only has been investigated intraspecifically. Here, we investigated the relationship between AFR and average lifetime reproductive success (LRS) across 34 bird species. We assessed differences in the deviation of the Optimal AFR (i.e., the species‐specific AFR associated with the highest LRS) from the age at sexual maturity, considering potential effects of life history as well as social and ecological factors. Most individuals adopted the species‐specific Optimal AFR and both the mean and Optimal AFR of species correlated positively with life span. Interspecific deviations of the Optimal AFR were associated with indices reflecting a change in LRS or survival as a function of AFR: a delayed AFR was beneficial in species where early AFR was associated with a decrease in subsequent survival or reproductive output. Overall, our results suggest that a delayed onset of reproduction beyond maturity is an optimal strategy explained by a long life span and costs of early reproduction. By providing the first empirical confirmations of key predictions of life‐history theory across species, this study contributes to a better understanding of life‐history evolution.     

Unusual records of deepwater teleosteans trawled off the western coast of Mexico

The first records of three midwater species for the Mexican ichthyofauna (Holtbyrnia laticauda, Brama dussumieri and Cubiceps baxteri), caught off the coast of Baja California, Mexico, in mid 2014, are reported. As far as is known, they are the first verified specimens, geo‐referenced and catalogued in a reference fish collection for the west coast of Mexico. The species' known distributions were extended northward in the eastern Pacific Ocean, ranging from 3495 to 8300 km.     

Synthesis and biological evaluation of trifluralin analogues as antileishmanial agents

A series of new analogues of trifluralin (TFL) were synthesized and characterized in view of changing the unfavorable properties that limits its use as antileishmanial agent. Some of the TFL analogues display more activity than a standard drug (miltefosine) against the promastigote forms of Leishmania infantum and Leishmania donovani and the intracellular form (THP-1 infected with L. infantum). All analogues showed a clear advantage over miltefosine, as they are not hemolytic. Some analogues can conjugate these characteristics with reduced cell toxicity and improved intracellular activity.     

Weight–length relationships of six batoids in the Ecuadorian Pacific

Weight–length relationships (WLR) were estimated for six batoids, namely: Urotrygon chilensis, Narcine entemedor, Rhinobatos leucorhynchus, Rhinobatos planiceps, Rhinobatos prahli and Urobatis tumbesensis captured in the Ecuadorian Pacific. Data were collected between October 2013 and August 2014 in two artisanal fishing ports. In addition, this represents the first WLR estimations for five of the species.     

Leptin activation of mTOR pathway in intestinal epithelial cell triggers lipid droplet formation,cytokine production and increased cell proliferation

Accumulating evidence suggests that obesity and enhanced inflammatory reactions are predisposing conditions for developing colon cancer. Obesity is associated with high levels of circulating leptin. Leptin is an adipocytokine that is secreted by adipose tissue and modulates immune response and inflammation. Lipid droplets (LD) are organelles involved in lipid metabolism and production of inflammatory mediators, and increased numbers of LD were observed in human colon cancer. Leptin induces the formation of LD in macrophages in a PI3K/mTOR pathway-dependent manner. Moreover, the mTOR is a serine/threonine kinase that plays a key role in cellular growth and is frequently altered in tumors. We therefore investigated the role of leptin in the modulation of mTOR pathway and regulation of lipid metabolism and inflammatory phenotype in intestinal epithelial cells (IEC-6 cells). We show that leptin promotes a dose- and time-dependent enhancement of LD formation. The biogenesis of LD was accompanied by enhanced CXCL1/CINC-1, CCL2/MCP-1 and TGF-β production and increased COX-2 expression in these cells. We demonstrated that leptin-induced increased phosphorylation of STAT3 and AKT and a dose and time-dependent mTORC activation with enhanced phosphorilation of the downstream protein P70S6K protein. Pre-treatment with rapamycin significantly inhibited leptin effects in LD formation, COX-2 and TGF-β production in IEC-6 cells. Moreover, leptin was able to stimulate the proliferation of epithelial cells on a mTOR-dependent manner. We conclude that leptin regulates lipid metabolism, cytokine production and proliferation of intestinal cells through a mechanism largely dependent on activation of the mTOR pathway, thus suggesting that leptin-induced mTOR activation may contribute to the obesity-related enhanced susceptibility to colon carcinoma.     

Comparison of Rates of Local Cerebral Glucose Utilization Determined with Deoxy[l-14C]glucose and Deoxy[6-14C]glucose

The activity of the pentose phosphate shunt pathway in brain is thought to be linked to neurotransmitter metabolism, glutathione reduction, and synthetic pathways requiring NADPH. There is currently no method available to assess flux of glucose through the pentose phosphate pathway in localized regions of the brain of conscious animals in vivo. Because metabolites of deoxy[1-14C]glucose are lost from brain when the experimental period of the deoxy[14C]glucose method exceeds 45 min, the possibility was considered that the loss reflected activity of this shunt pathway and that this hexose might be used to assay regional pentose phosphate shunt pathway activity in brain. Decarboxylation of deoxy[1-14C]glucose by brain extracts was detected in vitro, and small quantities of 14C were recovered in the 6-phosphodeoxygluconate fraction when deoxy[14C]glucose metabolites were isolated from freeze-blown brains and separated by HPLC. Local rates of glucose utilization determined with deoxy[1-14C]glucose and deoxy[6-14C]glucose were, however, similar in 20 brain structures at 45, 60, 90, and 120 min after the pulse, indicating that the rate of loss of 14CO2 from deoxy[1-14C]glucose-6-phosphate in normal adult rat brain is too low to permit assay pentose phosphate shunt activity in vivo. Further metabolism of deoxy[1-14]glucose-6-phosphate via this pathway does not interfere during routine use of the deoxyglucose method or explain the progressive decrease in calculated metabolic rate when the experimental period exceeds 45 min.     

Differential Gene Expression and Infection Profiles of Cutaneous and Mucosal Leishmania braziliensis Isolates from the Same Patient

BackgroundLeishmaniasis is a complex disease in which clinical outcome depends on factors such as parasite species, host genetics and immunity and vector species. In Brazil, Leishmania (Viannia) braziliensis is a major etiological agent of cutaneous (CL) and mucosal leishmaniasis (MCL), a disfiguring form of the disease, which occurs in ~10% of L. braziliensis-infected patients. Thus, clinical isolates from patients with CL and MCL may be a relevant source of information to uncover parasite factors contributing to pathogenesis. In this study, we investigated two pairs of L. (V.) braziliensis isolates from mucosal (LbrM) and cutaneous (LbrC) sites of the same patient to identify factors distinguishing parasites that migrate from those that remain at the primary site of infection.Conclusions/SignificanceDespite sharing high similarity at the genome structure and ploidy levels, the parasites exhibited divergent expressed genomes. The proteome and metabolome results indicated differential profiles between the cutaneous and mucosal isolates, primarily related to inflammation and chemotaxis. BALB/c infection revealed that the cutaneous isolates were more virulent than the mucosal parasites. Furthermore, our data suggest that the LbrPGF2S protein is a candidate to contribute to parasite virulence profiles in the mammalian host.     

Feeding behavior,life history,and virus transmission ability of Bemisia tabaci Mediterranean species (Hemiptera: Aleyrodidae) under elevated CO2

The continuous rise of CO₂ concentrations in the atmosphere is reducing plant nutritional quality for herbivores and indirectly affects their performance. The whitefly (Bemisia tabaci, Gennadius) is a major worldwide pest of agricultural crops causing significant yield losses. This study investigated the plant‐mediated indirect effects of elevated CO₂ on the feeding behavior and life history of B. tabaci Mediterranean species. Eggplants were grown under elevated and ambient CO₂ concentrations for 3 weeks after which plants were either used to monitor the feeding behavior of whiteflies using the Electrical Penetration Graph technique or to examine fecundity and fertility of whiteflies. Plant leaf carbon, nitrogen, phenols and protein contents were also analyzed for each treatment. Bemisia tabaci feeding on plants exposed to elevated CO₂ showed a longer phloem ingestion and greater fertility compared to those exposed to ambient CO₂ suggesting that B. tabaci is capable of compensating for the plant nutritional deficit. Additionally, this study looked at the transmission of the virus Tomato yellow leaf curl virus (Begomovirus) by B. tabaci exposing source and receptor tomato plants to ambient or elevated CO₂ levels before or after virus transmission tests. Results indicate that B. tabaci transmitted the virus at the same rate independent of the CO₂ levels and plant treatment. Therefore, we conclude that B. tabaci Mediterranean species prevails over the difficulties that changes in CO₂ concentrations may cause and it is predicted that under future climate change conditions, B. tabaci would continue to be considered a serious threat for agriculture worldwide.