Magnesium and iron deficiencies alter Cd accumulation in Salix viminalis L.

Evidence exists that Cd and certain nutrient elements, such as Fe and Mg, could share similar mechanisms of plant uptake and accumulation. Here we report that Mg and Fe deficiency in mature plants of Salix viminalis, grown in hydroponic solutions containing 5 µg ml^?1 of Cd, caused a significant increase in Cd accumulation in roots, stems and leaves. Cd (µg g^?1 dry weight) was determined following three treatments: 1) Cd treatment in complete nutrient solution; 2) Cd treatment with Fe deficiency; and 3) Cd treatment with Mg deficiency, yielding, respectively: in young leaves (65.3, 76.1, and 92.2), mature leaves (51.5 to 76.3 and 87.1), upper stems (80.6, 116.8, and 130.6) lower stems (67.2, 119, and 102.3), roots (377.1, 744.8, and 442,5). Our results suggest that Cd utilizes the same uptake and transport pathways as Mg and Fe. Evidence exists that Mg and Fe uptake and translocation could be further facilitated by plants as an adaptive response to deficiency of these elements. Such physiological reaction could additionally stimulate Cd accumulation. Although Cd uptake was mostly confined in roots, high Cd content in aerial plant parts (51.5–130.6 µg g^?1) indicates that the analysed Salix viminalis genotype is suitable for phytoextraction.     

The contribution of endophytic bacteria to Albizia lebbeck-mediated phytoremediation of tannery effluent contaminated soil

Toxicity of chromium often impairs the remediation capacity of plants used in phytoremediation of polluted soils. In this study, we have identified Albizia lebbeck as a prospective chromium hyperaccumulator and examined cultivable diversity of endophytes present in chromium-treated and control saplings. High numbers (22–100%) of endophytic bacteria, isolated from root, stem, and leaf tissues, could tolerate elevated (1–3 mM) concentrations of K₂CrO₇. 16S rRNA gene sequence-based phylogenetic analysis showed that the 118 isolates obtained comprised of 17 operational taxonomic units affiliated with the proteobacterial genera Rhizobium (18%), Marinomonas (1%), Pseudomonas (16%), and Xanthomonas (7%) but also with members of Firmicutes genera, such as Bacillus (35%) and Salinococcus (3%). The novel isolates belonging to Salinococcus and Bacillus could tolerate high K₂CrO₇ concentrations (3 mM) and also showed elevated activity of chromate reductase. In addition, majority (%) of the endophytic isolates also showed production of indole-3-acetic acid. Taken together, our results indicate that the innate endophytic bacterial community assists plants in reducing heavy metal toxicity.     

Seasonality of Antarctic minke whale (Balaenoptera bonaerensis) calls off the western Antarctic Peninsula

The Antarctic minke whale (Balaenoptera bonaerensis) is a difficult species to study because of its low visual detectability and preference for living within the sea ice habitat, accessible only by ice‐strengthened vessels. Recent identification of the Antarctic minke whale as the source of the seasonally ubiquitous bio‐duck call has allowed the use of this sound, as well as downsweeps, to investigate seasonality trends and diel patterns in Antarctic minke whale call production, and their relationship to sea ice cover. Passive acoustic data were collected using an autonomous Acoustic Recording Package (ARP) off the western Antarctic Peninsula. Bio‐duck calls were classified into four distinct call variants, with one variant having two subtypes. Bio‐duck calls were detected between April and November, with increasing call duration during the austral winter, indicating a strong seasonality in call production. Downsweeps, which were also attributed to Antarctic minke whales, were present throughout most months during the recording period, with a peak in July, and an absence in March and April. Both bio‐duck and downsweeps were significantly correlated with sea ice cover. No diel patterns were observed in bio‐duck calls or in downsweep call production at this site.     

Effect of Cultivation Time on Production of Antifungal Metabolite(s) by Streptomyces hygroscopicus in Laboratory‐Scale Bioreactor

Biological control agents offer one of the best alternatives to reduce the use of pesticides . Fungi from the genera Alternaria, Colletotrichum and Fusarium are listed among the most important storage pathogens of apple fruits. During storage, transport and marketing, pathogenic fungi can cause significant losses of apple fruits. This investigation studied the potential of Streptomyces hygroscopicus as a biocontrol agent against pathogenic fungi obtained from apple fruit samples expressing rot symptoms. Production of antifungal metabolites by S. hygroscopicus was carried out in 3‐l bench‐scale bioreactor (Biostat^® Aplus, Sartorius AG, Germany) during 7 days. Fermentation was carried out at 27°C with aeration rate of 0.5 vvm and agitation rate of 200 rpm. The aim was to analyse bioprocess parameters of batch biofungicide production in medium containing glucose as a carbon source and to examine at which stage of bioprocess production of antifungal metabolite(s) against six phytopathogenic fungi occurs. In vitro antifungal activity of the produced metabolites against six fungi of the genera Colletotrichum, Fusarium and Alternaria grown on potato dextrose agar were determined every 24 h using wells technique. Antifungal activity of cell‐free culture filtrate and filtrate treated with high temperature were tested. The filtrate treated with high temperature did not show any antifungal activity suggesting that active components are thermo unstable. Stationary phase of growth occurred between the third and fourth day of cultivation when production of secondary metabolites begins. Obtained results showed that maximal antifungal activity is achieved on fifth and sixth day of S. hygroscopicus cultivation under defined conditions (inhibition zone diameter higher than 30 mm for all test fungi).     

High pressure effect on photosynthetic properties of green plant leaves

We investigated the effects of high pressure treatment on green plant leaves of two species, red rose (Rosa rubiginosa L.) and silver birch male (Betula pendula Roth). Both species were treated with pressure up to 100 bar in order to explore stress reactions, including desirable or undesirable metabolites in plant. When increasing the pressure, chlorophyll (Chl) fluorescence maximum shifts to the wavelength of about 680 nm for both red rose and silver birch, with shift rates–0.062 nm/bar and–0.082 nm/bar, respectively. High pressure induces the changes of the position for the second fluorescence maximum at approximately 730 nm in both species with the same shift rate–0.083 nm/bar. When increasing pressure the change of the photosynthetic apparatus efficiency decreases for both plant species slowly and nonlinearly. High-pressure treatments irreversibly damaged the leaf tissue and at this way induced changes of Chl fluorescence and photosynthetic efficiency.     

Contribution to the knowledge on relic Stipa spp.-dominated ultramafic grasslands of the Central Balkans

The heterogeneity of the ultramafic vegetation of the Central Balkans is rather great. Although this vegetation has been continuously investigated, some gaps are still to be filled. For example, the lack of available data on ultramafic vegetation of the Republic of Macedonia is evident. In that light, we have investigated different relic Stipa species-dominated dry grasslands over ultramafic bedrock. Twenty relevés were made and compared to the similar vegetation types (i.e. Potentilla visianii, Centaureo kosaninii-Bromion fibrosi, “Thymion jankae”, Saturejo-Thymion and Alyssion heldreichii) by means of numerical analyses. We distinguished one new association and one informal community, providing them with diagnosis and lists of diagnostic, constant and dominant species. We also determined their syntaxonomic positions and relations to ultramafic syntaxa from the neighboring countries.     

High-quality draft genome sequence of Pseudomonas aeruginosa san ai,an environmental isolate resistant to heavy metals

Extremophiles - The strain Pseudomonas aeruginosa san ai, isolated from an extreme environment (industrial mineral cutting oil, pH 10), is able to survive and persist in the presence of a variety...     

A compact multiphoton 3D imaging system for recording fast neuronal activity

We constructed a simple and compact imaging system designed specifically for the recording of fast neuronal activity in a 3D volume. The system uses an Yb:KYW femtosecond laser we designed for use with acousto-optic deflection. An integrated two-axis acousto-optic deflector, driven by digitally synthesized signals, can target locations in three dimensions. Data acquisition and the control of scanning are performed by a LeCroy digital oscilloscope. The total cost of construction was one order of magnitude lower than that of a typical Ti:sapphire system. The entire imaging apparatus, including the laser, fits comfortably onto a small rig for electrophysiology. Despite the low cost and simplicity, the convergence of several new technologies allowed us to achieve the following capabilities: i) full-frame acquisition at video rates suitable for patch clamping; ii) random access in under ten microseconds with dwelling ability in the nominal focal plane; iii) three-dimensional random access with the ability to perform fast volume sweeps at kilohertz rates; and iv) fluorescence lifetime imaging. We demonstrate the ability to record action potentials with high temporal resolution using intracellularly loaded potentiometric dye di-2-ANEPEQ. Our design proffers easy integration with electrophysiology and promises a more widespread adoption of functional two-photon imaging as a tool for the study of neuronal activity. The software and firmware we developed is available for download at http://neurospy.org/ under an open source license.