Effect of electrical charges and fields on injury and viability of airborne bacteria

In this study, the effects of the electric charges and fields on the viability of airborne microorganisms were investigated. The electric charges of different magnitude and polarity were imparted on airborne microbial cells by a means of induction charging. The airborne microorganisms carrying different electric charge levels were then extracted by an electric mobility analyzer and collected using a microbial sampler. It was found that the viability of Pseudomonas fluorescens bacteria, used as a model for sensitive bacteria, carrying a net charge from 4100 negative to 30 positive elementary charges ranged between 40% and 60%; the viability of the cells carrying >2700 positive charges was below 1.5%. In contrast, the viability of the stress-resistant spores of Bacillus subtilis var. niger (used as simulant of anthrax-causing Bacillus anthracis spores when testing bioaerosol sensors in various studies), was not affected by the amount of electric charges on the spores. Because bacterial cells depend on their membrane potential for basic metabolic activities, drastic changes occurring in the membrane potential during aerosolization and the local electric fields induced by the imposed charges appeared to affect the sensitive cells' viability. These findings facilitate applications of electric charging for environmental control purposes involving sterilization of bacterial cells by imposing high electric charges on them. The findings from this study can also be used in the development of new bioaerosol sampling methods based on electrostatic principles.     

Riedel's thyroiditis in a patient with multiple sclerosis

Our patient developed Riedel's thyroiditis soon after having an exacerbation of multiple sclerosis (MS). MS has been associated with other autoimmune diseases, including thyroiditis, and both Hashimoto's thyroiditis and subacute thyroiditis have been described in connection with MS. Yet, we are not aware of any other patient reported to have concomitant MS and Riedel's thyroiditis. The association between MS and Riedel's thyroiditis remains obscure but may reflect an autoimmune disorder common to both diseases.     

Modelling Nutrient Uptake by Individual Hyphae of Arbuscular Mycorrhizal Fungi: Temporal and Spatial Scales for an Experimental Design

Arbuscular mycorrhizas, associations between plant roots and soil fungi, are ubiquitous among land plants. Arbuscular mycorrhizas can be beneficial for plants by overcoming limitations in nutrient supply. Hyphae, which are long and thin fungal filaments extending from the root surface into the soil, increase the volume of soil accessible for plant nutrient uptake. However, no models so far specifically consider individual hyphae. We developed a mathematical model for nutrient uptake by individual fungal hyphae in order to assess suitable temporal and spatial scales for a new experimental design where fungal uptake parameters are measured on the single hyphal scale. The model was developed based on the conservation of nutrients in an artificial cylindrical soil pore (capillary tube) with adsorbing wall, and analysed based on parameter estimation and non-dimensionalisation. An approximate analytical solution was derived using matched asymptotic expansion. Results show that nutrient influx into a hypha from a small capillary tube is characterized by three phases: Firstly, uptake rapidly decreases as the hypha takes up nutrients, secondly, the depletion zone reaches the capillary wall and thus uptake is sustained by desorption of nutrients from the capillary wall, and finally, uptake goes to zero after nutrients held on the capillary wall have been completely depleted. Simulating different parameter regimes resulted in recommending the use of capillaries filled with hydrogel instead of water in order to design an experiment operating over measurable time scales.     

Relationships among Doppler-derived umbilical artery absolute velocities, cardiac function, and placental volume blood flow and resistance in fetal sheep

We hypothesized that umbilical artery (UA) absolute blood flow velocities measured by Doppler ultrasonography reflect placental volume blood flow (Q(UA)) and placental vascular resistance (R(UA)) in a late gestation fetal sheep model. In addition, we examined the relationships between umbilical artery absolute blood flow velocities and parameters of fetal cardiac function. Twenty-six sheep fetuses were instrumented at 112-132 days of gestation. After a 5-day recovery period, experiments were performed under general anesthesia in 16 normal fetuses, in 5 fetuses after maternal administration of phenylephrine, and in 5 fetuses after placental embolization. The Q(UA) and arterial blood pressures were measured using a transit-time ultrasonic flow probe and a catheter placed into the descending aorta, respectively. UA peak systolic velocity (PSV), end-diastolic velocity (EDV), time-averaged maximum velocity (TAMXV), pulsatility index (PI), mean velocity (V(mean)), fetal cardiac output, ventricular ejection forces, and the proportion of isovolumetric relaxation time (IRT%) in the cardiac cycle were measured with the use of Doppler ultrasonography. Significant positive linear correlations were found between UA EDV, TAMXV, and V(mean) versus Q(UA), whereas UA PI had a significant negative correlation with Q(UA). Significant negative correlations were shown between UA EDV, TAMXV, and V(mean) versus R(UA). A significant positive correlation was present between UA PI and R(UA). Doppler-derived UA parameters did not correlate with fetal arterial blood pressures, cardiac output, ventricular ejection forces or IRT%. In fetal sheep, Doppler-derived UA PI and absolute velocities, except PSV, are closely related to directly measured Q(UA) and R(UA), validating the use of noninvasive Doppler velocimetry in the assessment of placental circulation.     

RTN4B interacting protein FAM134C promotes ER membrane curvature and has a functional role in autophagy

The endoplasmic reticulum (ER) is composed of a controlled ratio of sheets and tubules, which are maintained by several proteins with multiple functions. Reticulons (RTNs), especially RTN4, and DP1/Yop1p family members are known to induce ER membrane curvature. RTN4B is the main RTN4 isoform expressed in nonneuronal cells. In this study, we identified FAM134C as a RTN4B interacting protein in mammalian, nonneuronal cells. FAM134C localized specifically to the ER tubules and sheet edges. Ultrastructural analysis revealed that overexpression of FAM134C induced the formation of unbranched, long tubules or dense globular structures composed of heavily branched narrow tubules. In both cases, tubules were nonmotile. ER tubulation was dependent on the reticulon homology domain (RHD) close to the N-terminus. FAM134C plays a role in the autophagy pathway as its level elevated significantly upon amino acid starvation but not during ER stress. Moreover, FAM134C depletion reduced the number and size of autophagic structures and the amount of ER as a cargo within autophagic structures under starvation conditions. Dominant-negative expression of FAM134C forms with mutated RHD or LC3 interacting region also led to a reduced number of autophagic structures. Our results suggest that FAM134C provides a link between regulation of ER architecture and ER turnover by promoting ER tubulation required for subsequent ER fragmentation and engulfment into autophagosomes.     

RNA reveals a succession of active fungi during the decay of Norway spruce logs

Current knowledge of the succession of fungi in decaying wood is mostly based on fruit bodies and in vitro culture. Here, we investigated the changing community of metabolically active fungi during the decomposition of fallen Picea abies logs by directly extracting and barcode sequencing precursor rRNA. We also compared rRNA-derived amplicons of the 18S and ITS regions in 21 isolates and discuss the use of RNA as a marker of metabolically active fungi. The richness of active fungi, revealed as separated bands in DGGE, peaked in logs at an advanced stage of decay. Soft-rot fungi were common in the early stages but white- and brown-rot fungi became dominant as decay progressed. Ectomycorrhizal fungi were detected at an early stage, and they became the most abundant group in the late stages of succession. A comparison of rRNA-derived amplicons revealed that although ITS was detected in the form of precursor rRNA, introns within 18S rDNA were already spliced. As such, rRNA- and rDNA-derived amplicons would yield different profiles of active and total communities if profiling method is affected by amplicon length.     

Forest biomass,soil and biodiversity relationships originate from biogeographic affinity and direct ecological effects

Ecosystem biomass, soil conditions and the diversity of different taxa are often interrelated. These relationships could originate from biogeographic affinity (varying species pools) or from direct ecological effects within local communities. Disentangling regional and local causes is challenging as the former might mask the latter in natural ecosystems with varying habitat conditions. However, when the species pool contribution is considered in statistics, local ecological effects might be detected. In this study we disentangle the indirect effects of the species pool and direct ecological effects on the complex relationships among wood volume, soil conditions and diversities of different plant and fungal groups in 100 old‐growth forest sites (10 × 10 m) at the border of boreal and nemoral zones in northern Europe. We recorded all species for different vegetation groups: woody and herbaceous vascular plants, terricolous and epiphytic bryophytes and lichens. Fungal communities were detected by DNA‐based analyses from soil samples. Above‐ground wood volume was used as a proxy of biomass. We measured soil pH and nutrient content and obtained modelled climate parameters for each site. Species pool effect was considered by dividing sites into boreal and nemoral groups based on community composition. In order to disentangle direct and indirect effects, we applied variation partitioning, and raw and partial correlations. We found many significant positive relationships among studied variables. Many of these relationships were associated to boreal and nemoral species pools, thus indicating that biogeographic affinity of interacting plants and fungi largely defines forest diversity and functioning. At the same time, several relationships were significant also after considering biogeography: woody plant and ectomycorrhizal fungi diversities with wood volume, many plant and fungal groups with each other, or with soil conditions. These direct ecological interactions could be considered in forestry practices to achieve both economic gain and maintenance of biodiversity.     

Eco-efficiency indicator framework implemented in the metallurgical industry: part 2—a case study from the copper industry

Purpose

Sustainability differentiation has become an important issue for companies throughout the value chain. There is thus a need for detailed and credible analyses, which show the current status and point out where improvements can be done and how. The study describes how a comprehensive product-centric eco-efficiency indicator framework can be used to evaluate, benchmark, and communicate the sustainability of a copper production value chain. The indicator framework, together with the suggested data collection and simulation methods, aims at evaluating the whole system, while still enabling a focus on scopes of different width. The status of the environment, current production technologies, location-specific and process-specific issues all play a role in achieving sustainable development.

Methods

Copper cathode production from copper ore was chosen to exemplify the developed framework. Data sets from a simulation tool were used when available and LCI databases and LCA software were utilized for the remaining steps. The value chain is analyzed and the benchmark for each indicator built according to the new Gaia Refiner indicator framework. This method enables analysis of specific production steps with a higher degree of accuracy.

Results and discussion

The case study shows how some important environmental sustainability issues in copper production can be analyzed and benchmarked within a product group. Benchmark data is collected and used in the analysis for the selected system scope. Data availability is still an issue and the example shows which areas require more information in this context so that products and value chains can be benchmarked in the future on a more consistent basis. The energy mix, chemical use, and land use contribute to potential environmental sustainability risks within the product benchmarking group, while emissions control shows competitive environmental sustainability advantages for the case study.

Conclusions

The methodology is shown to work well in highlighting the sustainability advantages and risks of value chains in copper production with the selected system scope in a visual manner through the Sustainability Indicator “Flower.” The importance of a baseline is clear. The effect of the metal ore grade on the results shows that the scalability of the analysis system is very important. Scaling the system scope up will show the differences in varying value chains and scaling the system scope down will show efficiency differences between more similar value chains, thus visualizing where innovation has the biggest impact.

     

Glucose transport in a methylotrophic yeast Hansenula polymorpha

Glucose transport was studied in a methylotrophic yeast Hansenula polymorpha . Two kinetically different glucose transport systems were revealed in cells grown under different growth conditions. Glucose-repressed cells exhibited a low-affinity transport system ( K _m for glucose 1.75 mM) while glucose-derepressed and ethanol-grown cells had a high-affinity transport system ( K _m for glucose 0.05–0.06 mM). The high- and low-affinity transport systems differed in substrate specificity, sensitivity to pH, dinitrophenol and protonophore carbonyl cyanide- m -chlorophenyl-hydrazone. The kinetic rearrangement of the glucose transport system in response to altered growth conditions was dependent on de novo protein synthesis.