Glycerotoxin stimulates neurotransmitter release from N-type Ca2+ channel expressing neurons

Glycerotoxin (GLTx) is capable of stimulating neurotransmitter release at the frog neuromuscular junction by directly interacting with N-type Ca2+ (Cav2.2) channels. Here we have utilized GLTx as a tool to investigate the functionality of Cav2.2 channels in various mammalian neuronal preparations. We first adapted a fluorescent-based high-throughput assay to monitor glutamate release from rat cortical synaptosomes. GLTx potently stimulates glutamate secretion and Ca2+ influx in synaptosomes with an EC50 of 50 pm. Both these effects were prevented using selective Cav2.2 channel blockers suggesting the functional involvement of Cav2.2 channels in mediating glutamate release in this system. We further show that both Cav2.1 (P/Q-type) and Cav2.2 channels contribute equally to depolarization-induced glutamate release. We then investigated the functionality of Cav2.2 channels at the neonatal rat neuromuscular junction. GLTx enhances both spontaneous and evoked neurotransmitter release causing a significant increase in the frequency of postsynaptic action potentials. These effects were blocked by specific Cav2.2 channel blockers demonstrating that either GLTx or its derivatives could be used to selectively enhance the neurotransmitter release from Cav2.2-expressing mammalian neurons.     

Apolipoprotein E gene polymorphism effects triglycerides but not CAD risk in Caucasian women younger than 65 years

The pathogenesis of CAD is similar in man and woman, yet some risk factors have a greater impact on the CAD risk in woman than in man. In this study we assessed the effect of the apoE gene polymorphism on lipid metabolism and risk for CAD in women younger than 65 years (premature CAD). In a cross-sectional case-control study, 147 female Caucasian patients with premature CAD (confirmed by coronarography) were compared with a control group of 114 healthy Caucasian women. The apoE allele frequencies of patients vs. controls were 5.1% vs. 5.7% for 2, 85.4% vs. 83.3% for 3, and 9.5% vs. 11% for epsilon4. The subjects with epsilon2/3 genotype had statistically significantly higher triglycerides levels than the subjects with epsilon3/3 genotype (2.23 +/- 2.13 mmol.L(-1) vs. 1.73 +/- 0.84 mmol.L(-1); p<0.05). Logistic regression analysis revealed no association between risk genotypes (3/4 and 4/4) of the apoE gene polymorphism and CAD risk (OR 0.9; 95% CI 0. 5-1.7, P=0.7). We observed metabolic clustering of diabetes mellitus, arterial hypertension, higher BMI and triglycerides, and lower HDL cholesterol in the CAD group compared to the control group. Arterial hypertension, diabetes, HDL cholesterol level, and BMI were independent risk factors for premature CAD in female population, whereas, the risk genotype of the apoE gene polymorphism was not. In conclusion, in Slovene women risk genotypes of the apoE gene polymorphism are not associated with premature CAD; a metabolic clustering of diabetes, HDL, triglycerides and arterial hypertension is frequently present in Caucasian women with premature CAD.     

Dry calcareous grasslands from two neighboring biogeographic regions: relationship between plant traits and rarity

European dry grasslands formed of the Festuco-Brometea type are among the most diverse plant communities within agricultural landscapes. We examined floristic composition, functional trait structure and threatened species occurrence in grasslands of this type from in two distinct biogeographic regions, Dinaric (NW Balkan) and the Central European. In the Central European region this type of grassland is threatened by a decline in traditional extensive management. We tested, if differences in the level of threat between regions are matched by differences in community-weighted means for resource use strategy traits and occurrence of Red List (threatened) species. We then tested if threatened species differed in their traits from other species and if threatened species richness was related to CWM for resource use strategy traits. The communities from the Central European region had significantly higher SLA and lower LDMC, which perhaps reflects an increase in intensive agriculture promoting fast-growing species. Threatened species occurrence did not differ significantly between regions, but threatened species richness was significantly negatively correlated with CWM for height and SLA. This may suggest that threatened species are less likely to occur in high productivity communities where light competition is intense. This study provides initial evidence that changes in CWM for resource use strategy traits may provide a useful means for predicting threatened species loss in dry grassland ecosystems.     

Political Systems Affect Mobile and Sessile Species Diversity – A Legacy from the Post-WWII Period

Political ideologies, policies and economy affect land use which in turn may affect biodiversity patterns and future conservation targets. However, few studies have investigated biodiversity in landscapes with similar physical properties but governed by different political systems. Here we investigate land use and biodiversity patterns, and number and composition of birds and plants, in the borderland of Austria, Slovenia and Hungary. It is a physically uniform landscape but managed differently during the last 70 years as a consequence of the political “map” of Europe after World War I and II. We used a historical map from 1910 and satellite data to delineate land use within three 10-kilometre transects starting from the point where the three countries meet. There was a clear difference between countries detectable in current biodiversity patterns, which relates to land use history. Mobile species richness was associated with current land use whereas diversity of sessile species was more associated with past land use. Heterogeneous landscapes were positively and forest cover was negatively correlated to bird species richness. Our results provide insights into why landscape history is important to understand present and future biodiversity patterns, which is crucial for designing policies and conservation strategies across the world.     

Limited Evidence for Parent-of-Origin Effects in Inflammatory Bowel Disease Associated Loci

Background

Genome-wide association studies of two main forms of inflammatory bowel diseases (IBD), Crohn’s disease (CD) and ulcerative colitis (UC), have identified 99 susceptibility loci, but these explain only ∼23% of the genetic risk. Part of the ‘hidden heritability’ could be in transmissible genetic effects in which mRNA expression in the offspring depends on the parental origin of the allele (genomic imprinting), since children whose mothers have CD are more often affected than children with affected fathers. We analyzed parent-of-origin (POO) effects in Dutch and Indian cohorts of IBD patients.

Methods

We selected 28 genetic loci associated with both CD and UC, and tested them for POO effects in 181 Dutch IBD case-parent trios. Three susceptibility variants in NOD2 were tested in 111 CD trios and a significant finding was re-evaluated in 598 German trios. The UC-associated gene, BTNL2, reportedly imprinted, was tested in 70 Dutch UC trios. Finally, we used 62 independent Indian UC trios to test POO effects of five established Indian UC risk loci.

Results

We identified POO effects for NOD2 (L1007fs; OR = 21.0, P-value = 0.013) for CD; these results could not be replicated in an independent cohort (OR = 0.97, P-value = 0.95). A POO effect in IBD was observed for IL12B (OR = 3.2, P-value = 0.019) and PRDM1 (OR = 5.6, P-value = 0.04). In the Indian trios the IL10 locus showed a POO effect (OR = 0.2, P-value = 0.03).

Conclusions

Little is known about the effect of genomic imprinting in complex diseases such as IBD. We present limited evidence for POO effects for the tested IBD loci. POO effects explain part of the hidden heritability for complex genetic diseases but need to be investigated further.     

Discovery of (phenylureido)piperidinyl benzamides as prospective inhibitors of bacterial autolysin E from Staphylococcus aureus

Autolysin E (AtlE) is a cell wall degrading enzyme that catalyzes the hydrolysis of the β-1,4-glycosidic bond between the N-acetylglucosamine and N-acetylmuramic acid units of the bacterial peptidoglycan. Using our recently determined crystal structure of AtlE from Staphylococcus aureus and a combination of pharmacophore modeling, similarity search, and molecular docking, a series of (Phenylureido)piperidinyl benzamides were identified as potential binders and surface plasmon resonance (SPR) and saturation-transfer difference (STD) NMR experiments revealed that discovered compounds bind to AtlE in a lower micromolar range. (phenylureido)piperidinyl benzamides are the first reported non-substrate-like compounds that interact with this enzyme and enable further study of the interaction of small molecules with bacterial AtlE as potential inhibitors of this target.     

Life-cycle assessment of a hydrogen-based uninterruptible power supply system using renewable energy

Purpose

The paper provides an empirical assessment of an uninterruptible power supply (UPS) system based on hydrogen technologies (HT-UPS) using renewable energy sources (RES) with regard to its environmental impacts and a comparison to a UPS system based on the internal combustion engine (ICE-UPS).

Methods

For the assessment and comparison of the environmental impacts, the life-cycle assessment (LCA) method was applied, while numerical models for individual components of the UPS systems (electrolyser, storage tank, fuel cell and ICE) were developed using GaBi software. The scope of analysis was cradle-to-end of utilisation with functional unit 1 kWh of uninterrupted electricity produced. For the life-cycle inventory analysis, quantitative data was collected with on-site measurements on an experimental system, project documentation, GaBi software generic databases and literature data. The CML 2001 method was applied to evaluate the system’s environmental impacts. Energy consumption of the manufacturing phase was estimated from gross value added (GVA) and the energy intensity of the industry sector in the manufacturer’s country.

Results and discussion

In terms of global warming (GW), acidification (A), abiotic depletion (AD) and eutrophication (E), manufacturing phase of HT-UPS accounts for more than 97 % of environmental impacts. Electrolyser in all its life-cycle phases contributes above 50 % of environmental impacts to the system’s GW, A and AD. Energy return on investment (EROI) for the HT-UPS has been calculated to be 0.143 with distinction between renewable (roughly 60 %) and non-renewable energy resources inputs. HT-UPS’s life-cycle GW emissions have been calculated to be 375 g of CO₂ eq per 1 kWh of uninterruptible electric energy supplied. All these values have also been calculated for the ICE-UPS and show that in terms of GW, A and AD, the ICE-UPS has bigger environmental impacts and emits 1,190 g of CO₂ eq per 1 kWh of uninterruptible electric energy supplied. Both systems have similar operation phase energy efficiency. The ICE-UPS has a higher EROI but uses almost none RES inputs.

Conclusions

The comparison of two different technologies for providing UPS has shown that in all environmental impact categories, except eutrophication, the HT-UPS is the sounder system. Most of HT-UPS’s environmental impacts result from the manufacturing phase. On the contrary, ICE-UPS system’s environmental impacts mainly result from operational phase. Efficiency of energy conversion from electricity to hydrogen to electricity again is rather low, as is EROI, but these will likely improve as the technology matures.