Measuring ecological impact of water consumption by bioethanol using life cycle impact assessment

Purpose  

Though the development of biofuel has attracted numerous studies for quantifying potential water demand applying life cycle thinking, the impacts of biofuel water consumption still remain unknown. In this study, we aimed to quantify ecological impact associated with corn-based bioethanol water consumption in Minnesota in responding to different refinery expansion scenarios by applying a life cycle impact assessment method.     

Neuronal Basis of Innate Olfactory Attraction to Ethanol in Drosophila

The decision to move towards a mating partner or a food source is essential for life. The mechanisms underlying these behaviors are not well understood. Here, we investigated the role of octopamine – the invertebrate analogue of noradrenaline – in innate olfactory attraction to ethanol. We confirmed that preference is caused via an olfactory stimulus by dissecting the function of the olfactory co-receptor Orco (formally known as OR83b). Orco function is not required for ethanol recognition per se, however it plays a role in context dependent recognition of ethanol. Odor-evoked ethanol preference requires the function of Tbh (Tyramine β hydroxalyse), the rate-limiting enzyme of octopamine synthesis. In addition, neuronal activity in a subset of octopaminergic neurons is necessary for olfactory ethanol preference. Notably, a specific neuronal activation pattern of tyraminergic/octopaminergic neurons elicit preference and is therefore sufficient to induce preference. In contrast, dopamine dependent increase in locomotor activity is not sufficient for olfactory ethanol preference. Consistent with the role of noradrenaline in mammalian drug induced rewards, we provide evidence that in adult Drosophila the octopaminergic neurotransmitter functions as a reinforcer and that the molecular dissection of the innate attraction to ethanol uncovers the basic properties of a response selection system.     

State-of-the art data normalization methods improve NMR-based metabolomic analysis

Extracting biomedical information from large metabolomic datasets by multivariate data analysis is of considerable complexity. Common challenges include among others screening for differentially produced metabolites, estimation of fold changes, and sample classification. Prior to these analysis steps, it is important to minimize contributions from unwanted biases and experimental variance. This is the goal of data preprocessing. In this work, different data normalization methods were compared systematically employing two different datasets generated by means of nuclear magnetic resonance (NMR) spectroscopy. To this end, two different types of normalization methods were used, one aiming to remove unwanted sample-to-sample variation while the other adjusts the variance of the different metabolites by variable scaling and variance stabilization methods. The impact of all methods tested on sample classification was evaluated on urinary NMR fingerprints obtained from healthy volunteers and patients suffering from autosomal polycystic kidney disease (ADPKD). Performance in terms of screening for differentially produced metabolites was investigated on a dataset following a Latin-square design, where varied amounts of 8 different metabolites were spiked into a human urine matrix while keeping the total spike-in amount constant. In addition, specific tests were conducted to systematically investigate the influence of the different preprocessing methods on the structure of the analyzed data. In conclusion, preprocessing methods originally developed for DNA microarray analysis, in particular, Quantile and Cubic-Spline Normalization, performed best in reducing bias, accurately detecting fold changes, and classifying samples.

     

Infection of Coscinodiscus spp. by the parasitoid nanoflagellate Pirsonia diadema: II. Selective infection behaviour for host species and individual host cells

The parasitoid nanoflagellate (PNF) Pirsonia diadema is hostspecific for the marine centric diatom Coscinodiscus spp. Experimentsshowed that flagellates significantly prefer C. wailesii overC.granii as host species (interspecific selectivity). This preferencewas independent of light conditions (dark, irradiance of 10and 70 µmol m^–2 s^–1) and temperature (10 and15C). Among unicellular host diatoms, the infection behaviourwas selective for individual cells: already infected C.graniicells were more attractive for further flagellate attachmentthan non-infected cells (intraspecific selectivity). Individualcells (     

Role of arginine in chemical cross-linking with N-hydroxysuccinimide esters

In order to clarify whether arginine has a promoting effect on the acylation of hydroxyl groups of serine, threonine, or tyrosine by homobifunctional cross-linking agents in aqueous solution, we carried out systematic experiments with model peptides, comparing relative reaction yields with covalently protected and unprotected arginines by MALDI-MS. The guanidinium group could be demonstrated to contribute to the reactivity of hydroxyl groups toward N-hydroxysuccinimide esters and catalyze the nucleophilic substitution, probably via hydrogen bonds.     

The activation of the decapping enzyme DCP2 by DCP1 occurs on the EDC4 scaffold and involves a conserved loop in DCP1

The removal of the 5′-cap structure by the decapping enzyme DCP2 and its coactivator DCP1 shuts down translation and exposes the mRNA to 5′-to-3′ exonucleolytic degradation by XRN1. Although yeast DCP1 and DCP2 directly interact, an additional factor, EDC4, promotes DCP1–DCP2 association in metazoan. Here, we elucidate how the human proteins interact to assemble an active decapping complex and how decapped mRNAs are handed over to XRN1. We show that EDC4 serves as a scaffold for complex assembly, providing binding sites for DCP1, DCP2 and XRN1. DCP2 and XRN1 bind simultaneously to the EDC4 C-terminal domain through short linear motifs (SLiMs). Additionally, DCP1 and DCP2 form direct but weak interactions that are facilitated by EDC4. Mutational and functional studies indicate that the docking of DCP1 and DCP2 on the EDC4 scaffold is a critical step for mRNA decapping in vivo. They also revealed a crucial role for a conserved asparagine–arginine containing loop (the NR-loop) in the DCP1 EVH1 domain in DCP2 activation. Our data indicate that DCP2 activation by DCP1 occurs preferentially on the EDC4 scaffold, which may serve to couple DCP2 activation by DCP1 with 5′-to-3′ mRNA degradation by XRN1 in human cells.     

Non-Selective Calcium Channel Blocker Bepridil Decreases Secondary Pathology in Mice after Photothrombotic Cortical Lesion

Experimental studies have identified a complex link between neurodegeneration, β-amyloid (Aβ) and calcium homeostasis. Here we asked whether early phase β-amyloid pathology in transgenic hAPP_SL mice exaggerates the ischemic lesion and remote secondary pathology in the thalamus, and whether a non-selective calcium channel blocker reduces these pathologies. Transgenic hAPP_SL (n = 33) and non-transgenic (n = 30) male mice (4–5 months) were subjected to unilateral cortical photothrombosis and treated with the non-selective calcium channel blocker bepridil (50 mg/kg, p.o., once a day) or vehicle for 28 days, starting administration 2 days after the operation. Animals were then perfused for histological analysis of infarct size, Aβ and calcium accumulation in the thalamus. Cortical photothrombosis resulted in a small infarct, which was associated with atypical Aβ and calcium accumulation in the ipsilateral thalamus. Transgenic mice had significantly smaller infarct volumes than non-transgenic littermates (P<0.05) and ischemia-induced rodent Aβ accumulation in the thalamus was lower in transgenic mice compared to non-transgenic mice (P<0.01). Bepridil decreased calcium load in the thalamus (P<0.01). The present data suggest less pronounced primary and secondary pathology in hAPP_SL transgenic mice after ischemic cortical injury. Bepridil particularly decreased calcium pathology in the thalamus following ischemia.     

The β-Hemolysin and Intracellular Survival of Streptococcus agalactiae in Human Macrophages

S. agalactiae (group B streptococci, GBS) is a major microbial pathogen in human neonates and causes invasive infections in pregnant women and immunocompromised individuals. The S. agalactiae β-hemolysin is regarded as an important virulence factor for the development of invasive disease. To examine the role of β-hemolysin in the interaction with professional phagocytes, the THP-1 monocytic cell line and human granulocytes were infected with a serotype Ia S. agalactiae wild type strain and its isogenic nonhemolytic mutant. We could show that the nonhemolytic mutants were able to survive in significantly higher numbers than the hemolytic wild type strain, in THP-1 macrophage-like cells and in assays with human granulocytes. Intracellular bacterial multiplication, however, could not be observed. The hemolytic wild type strain stimulated a significantly higher release of Tumor Necrosis Factor-α than the nonhemolytic mutant in THP-1 cells, while similar levels of the chemokine Interleukin-8 were induced. In order to investigate bacterial mediators of IL-8 release in this setting, purified cell wall preparations from both strains were tested and found to exert a potent proinflammatory stimulus on THP-1 cells. In conclusion, our results indicate that the β-hemolysin has a strong influence on the intracellular survival of S. agalactiae and that a tightly controlled regulation of β-hemolysin expression is required for the successful establishment of S. agalactiae in different host niches.     

Location of a dicyclohexylcarbodiimide-reactive glutamate residue in the Neurospora crassa plasma membrane H+-ATPase

The proton pump (H+-ATPase) found in the plasma membrane of the fungus Neurospora crassa is inactivated by dicyclohexylcarbodiimide (DCCD). Kinetic and labeling experiments have suggested that inactivation at 0 degrees C results from the covalent attachment of DCCD to a single site in the Mr = 100,000 catalytic subunit (Sussman, M. R., and Slayman, C. W. (1983) J. Biol. Chem. 258, 1839-1843). In the present study, when [14C]DCCD-labeled enzyme was treated with the cleavage reagent, N-bromosuccinimide, a single major radioactive peptide fragment migrating at about Mr = 5,300 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was produced. The fragment was coupled to glass beads and partially sequenced by automated solid-phase Edman degradation at the amino terminus and at an internal tryptic cleavage site. By comparison to the DNA-derived amino acid sequence for the entire Mr = 100,000 polypeptide (Hager, K., and Slayman, C. W. (1986) Proc. Natl. Acad. Sci. U. S. A. 83, 7693-7697), the fragment has been identified as arising by cleavage at tyrosine 100 and tryptophan 141. Covalently incorporated [14C]DCCD was released at a position corresponding to glutamate 129. The DCCD-reactive glutamate is located in the middle of the first of eight predicted transmembrane sequences. When the sequence surrounding the DCCD site is compared to that surrounding the DCCD-reactive residue of two other proton pumps, the F0F1-ATPase and cytochrome c oxidase, no homology is apparent apart from an abundance of hydrophobic amino acids.