Anaerobic biotechnological approaches for production of liquid energy carriers from biomass

In recent years, increasing attention has been paid to the use of renewable biomass for energy production. Anaerobic biotechnological approaches for production of liquid energy carriers (ethanol and a mixture of acetone, butanol and ethanol) from biomass can be employed to decrease environmental pollution and reduce dependency on fossil fuels. There are two major biological processes that can convert biomass to liquid energy carriers via anaerobic biological breakdown of organic matter: ethanol fermentation and mixed acetone, butanol, ethanol (ABE) fermentation. The specific product formation is determined by substrates and microbial communities available as well as the operating conditions applied. In this review, we evaluate the recent biotechnological approaches employed in ethanol and ABE fermentation. Practical applicability of different technologies is discussed taking into account the microbiology and biochemistry of the processes.     

How do low dispersal species establish large range sizes? The case of the water beetle Graphoderus bilineatus

Species’ dispersal abilities have been considered a major driving force in establishment and maintenance of large range sizes. However, recent studies question the general validity of this relationship because the relationship between dispersal ability and range size might in some cases be less important than species phylogeny or local spatial attributes. In this study we used the water beetle Graphoderus bilineatus a philopatric species of conservation concern in Europe as a model to explain large range size and to support effective conservation measures for such species that also have limited dispersal. We recorded the presence/absence of G. bilineatus and measured 14 habitat and 20 landscape variables at 228 localities in Estonia, Poland and Sweden within the core range of the species. Using information theory and average multivariate logistic regression models we determined that presence of G. bilineatus depended on landscape connectivity, distance to a possible source habitat, and stability of the site; however, specificity of habitat characteristics was not vital for the species. We reason that the large range of G. bilineatus is best explained by the historical combination of lakes, river systems and wetlands which used to be highly connected throughout the central plains of Europe. Our data suggest that a broad habitat niche can prevent landscape elements from becoming barriers for species like G. bilineatus. Therefore, we question the usefulness of site protection as conservation measures for G. bilineatus and similar philopatric species. Instead, conservation actions should be focused at the landscape level to ensure a long‐term viability of such species across their range.     

Hydrothermal treatment of wheat straw at pilot plant scale using a three-step reactor system aiming at high hemicellulose recovery, high cellulose digestibility and low lignin hydrolysis

A pilot plant (IBUS) consisting of three reactors was used for hydrothermal treatment of wheat straw (120-150 kg/h) aiming at co-production of bioethanol (from sugars) and electricity (from lignin). The first reactor step was pre-soaking at 80 degrees C, the second extraction of hemicellulose at 170-180 degrees C and the third improvement of the enzymatic cellulose convertibility at 195 degrees C. Water added to the third reactor passed countercurrent to straw. The highest water addition (600 kg/h) gave the highest hemicellulose recovery (83%). With no water addition xylose degradation occurred resulting in low hemicellulose recovery (33%) but also in high glucose yield in the enzymatic hydrolysis (72 g/100g glucose in straw). Under these conditions most of the lignin was retained in the fibre fraction, which resulted in a lignin rich residue with high combustion energy (up to 31 MJ/kg) after enzymatic hydrolysis of cellulose and hemicellulose.     

Discovery and SAR of new benzazepines as potent and selective 5-HT(2C) receptor agonists for the treatment of obesity

We report on the synthesis, biological evaluation and structure-activity relationships for a series of 3-benzazepine derivatives as 5-HT(2C) receptor agonists. The compounds were evaluated in functional assays measuring [3H] phosphoinositol turnover in HEK-293 cells transiently transfected with h5-HT(2C), h5-HT(2A) or h5-HT(2B) receptors. Several compounds are shown to be potent and selective 5-HT(2C) receptor agonists, which decrease food intake in a rat feeding model.     

Mass Spectrometric Studies of the Effect of pH on the Accumulation of Intermediates in Denitrification by Paracoccus denitrificans

We have used a quadrupole mass spectrometer with a gas-permeable membrane inlet for continuous measurements of the production of N₂O and N₂ from nitrate or nitrite by cell suspensions of Paracoccus denitrificans. The use of nitrate and nitrite labeled with ¹⁵N was shown to simplify the interpretation of the results when these gases were measured. This approach was used to study the effect of pH on the production of denitrification intermediates from nitrate and nitrite under anoxic conditions. The kinetic patterns observed were quite different at acidic and alkaline pH values. At pH 5.5, first nitrate was converted to nitrite, then nitrite was converted to N₂O, and finally N₂O was converted to N₂. At pH 8.5, nitrate was converted directly to N₂, and the intermediates accumulated to only low steady-state concentrations. The sequential usage of nitrate, nitrite, and nitrous oxide observed at pH 5.5 was simulated by using a kinetic model of a branched electron transport chain in which alternative terminal reductases compete for a common reductant.     

Analysis of qPCR data by converting exponentially related Ct values into linearly related X0 values

A common method for calculating results from qPCR experiments is the comparative Ct method, also called the 2(-ΔΔCt) method. However, several assumptions are included in the 2(-ΔΔCt) method and standard statistical analyses are not directly applicable. Here, we describe a different method, the X(0) method, for result calculations and statistical analysis from qPCR experiments. The X(0) method differs from the 2(-ΔΔCt) method by introducing a conversion of the exponentially related Ct values into linearly related X(0) values, which represent the amount of starting material in a qPCR experiment. Results calculated by the X(0) method are illustrated for qPCR experiments with technical and biological replicates, including procedures to calculate standard deviations. Incorporation of primer efficiencies in calculations by the X(0) method is also described. Altogether, the X(0) method constitutes a very simple and accurate alternative to the 2(-ΔΔCt) method for result calculations from qPCR data.     

EVIDENCE FOR IMPACTS OF NONINDIGENOUS MACROALGAE: A META‐ANALYSIS OF EXPERIMENTAL FIELD STUDIES1

Invasions by nonindigenous macroalgal species (NIMS) potentially cause severe impacts on native species. We conducted a meta‐analysis of 18 field‐based manipulative experiments to quantify the direction and magnitude of impacts (Hedges effect size d, hereafter ES). We found significant small‐to‐medium negative effects on “macrophyte abundance” (cover, biomass of native taxa; ES_cumulative = ?0.30) and medium‐to‐large negative effects on “macrophyte assemblages” (richness, diversity, total abundance; ES_cumulative = ?0.70). In contrast, ES_cumulative were not significant for “macrophyte processes” (growth, mortality; ES_cumulative = ?0.39), “animal abundance” (densities; ES_cumulative = ?0.13), or “animal assemblages” (richness, diversity; ES_cumulative = 0.75). The nonsignificant effect sizes were characterized by low sample sizes and should be interpreted with caution. Three study‐specific effect sizes were particularly large (cumulative are likely biased toward larger effects because only the most conspicuous NIMS have been tested and because nonsignificant results are less likely to be published. To better understand the impacts of NIMS, more manipulative experiments are needed, testing more species and under contrasting environmental conditions. Future studies should include procedural control treatments and report the abundance of the NIMS to avoid ambiguous interpretations. In conclusion, current experimental evidence shows that NIMS have, on average, small‐to‐large negative impacts on native plant species and assemblages. It is possible that these effects can result in severe consequences when accumulated over long time periods and large spatial scales.     

Targeting of Non-Dominant Antigens as a Vaccine Strategy to Broaden T-Cell Responses during Chronic Viral Infection

In this study, we compared adenoviral vaccine vectors with the capacity to induce equally potent immune responses against non-dominant and immunodominant epitopes of murine lymphocytic choriomeningitis virus (LCMV). Our results demonstrate that vaccination targeting non-dominant epitopes facilitates potent virus-induced T-cell responses against immunodominant epitopes during subsequent challenge with highly invasive virus. In contrast, when an immunodominant epitope was included in the vaccine, the T-cell response associated with viral challenge remained focussed on that epitope. Early after challenge with live virus, the CD8+ T cells specific for vaccine-encoded epitopes, displayed a phenotype typically associated with prolonged/persistent antigenic stimulation marked by high levels of KLRG-1, as compared to T cells reacting to epitopes not included in the vaccine. Notably, this association was lost over time in T cells specific for the dominant T cell epitopes, and these cells were fully capable of expanding in response to a new viral challenge. Overall, our data suggests a potential for broadening of the antiviral CD8+ T-cell response by selecting non-dominant antigens to be targeted by vaccination. In addition, our findings suggest that prior adenoviral vaccination is not likely to negatively impact the long-term and protective immune response induced and maintained by a vaccine-attenuated chronic viral infection.