Removal of selenite from wastewater using microbial fuel cells

Simultaneous electricity generation and selenium removal was evaluated in single-chamber microbial fuel cells (MFCs) with acetate and glucose as carbon sources. Power output was not affected by selenite up to 125 mg l⁻¹ with glucose as substrate. Coulombic efficiencies of MFCs with glucose increased from 25% to 38% at 150 mg Se l⁻¹. About 99% of 50 and 200 mg Se l⁻¹ selenite was removed in 48 and 72 h for MFCs fed with acetate and glucose, respectively, demonstrating the potential of using MFC technology for Se remediation.     

Quantification of indole-3-acetic acid from plant associated <Emphasis Type="Italic">Bacillus</Emphasis> spp. and their phytostimulatory effect on <Emphasis Type="Italic">Vigna radiata</Emphasis> (L.)

Sixteen Bacillus strains isolated from rhizosphere, histoplane and phyllosphere of different plant species were identified by 16S rDNA gene sequencing and evaluated for in vitro auxin production as well as growth stimulation of Vigna radiata (L.) Wilczek. Auxin production by Bacillus spp. in L-broth medium supplemented with 1,000 μg ml⁻¹ L-tryptophan ranges from 0.60 to 3.0 μg IAA ml⁻¹ as revealed by gas chromatography and mass spectrometric (GC–MS) analysis. Rhizospheric isolates exhibit relatively more IAA synthesis than histoplane and phyllosphere isolates. Plant microbe interaction experiments conducted under gnotobiotic conditions recorded 55.55, 46.46 and 46.20% increase in shoot length with Bacillus megaterium MiR-4, B. pumilus NpR-1 and B. subtilis TpP-1, respectively, over control. Bacillus inoculations also increased shoot fresh weight with B. megaterium MiR-4 (60.94%) and B. pumilus NpR-1 (37.76%). Highly significant positive correlation between auxin production analyzed by GC–MS and shoot length (r = 0.687**, P = 0.01) and shoot fresh weight (r = 0.703**, P = 0.01) was noted under gnotobiotic conditions. Similarly, significant correlation was also found between auxin production by Bacillus spp. (GC–MS analysis) and different growth parameters such as shoot length (r = 0.495*, P = 0.05), number of pods (r = 0.498*, P = 0.05) and grain weight (r = 0.537*, P = 0.05) at full maturity under natural wire house conditions. Results showed that auxin production potential of plant associated Bacillus spp. can be effectively exploited to enhance the growth and yield of V. radiata.     

Assessment of the eutrophication status of transitional,coastal and marine waters within OSPAR

Eutrophication (nutrient enrichment and subsequent processes) and its adverse ecosystem effects have been discussed as main issues over the last 20 years in international conferences and conventions for the protection of the marine environment such as the North Sea Conferences and the 1992 OSPAR Convention (OSPAR; which combined and updated the 1972 Oslo Convention on dumping waste at the sea and the 1974 Paris Convention on land-based sources of marine pollution). OSPAR committed itself to reduce phosphorus and nitrogen inputs (in the order of 50% compared with 1985) into the marine areas and ‘to combat eutrophication to achieve, by the year 2010, a healthy marine environment where eutrophication does not occur’. Within OSPAR, the Comprehensive Procedure (COMPP) has been developed and used to assess the eutrophication status of the OSPAR maritime area in an harmonised way. This is based on classification in terms of the following types of areas Non-Problem Areas (no effects), Potential Problem Areas (not enough data to assess effects) and Problem Areas (effects due to elevated nutrients and/or due to transboundary transport from adjacent areas). The COMPP consists of a set of harmonised assessment criteria with their area-specific assessment levels and an integrated area classification approach. The criteria cover all aspects of nutrient enrichment (nutrient inputs, concentrations and ratios) as well as possible direct effects (e.g. increased levels of nuisance and/or toxic phytoplankton species, shifts and/or losses of submerged aquatic vegetation) and indirect effects (e.g. oxygen deficiency, changes and/or death of benthos, death of fish, algal toxins). The COMPP also includes supporting environmental factors. It takes account of synergies and harmonisation with the EC Water Framework Directive, and has formed a major basis for the EC eutrophication guidance. Recently, additional components, such as total nitrogen, total phosphorus and transboundary transports have been included in the assessment of, e.g. the German Bight. The second application of the COMPP resulting in an update of the eutrophication status of the OSPAR maritime area will be finalised in 2008, and will include the agreed integrated set of Ecological Quality Objectives (EcoQOs) with respect to eutrophication. Guest editors: J. H. Andersen & D. J. Conley Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark     

Assessment of antifungal effects of a novel compound from <Emphasis Type="Italic">Burkholderia cepacia</Emphasis> against <Emphasis Type="Italic">Fusarium solani</Emphasis> by fluorescent staining

A novel compound CF66I produced by Burkholeria cepacia was investigated for its antifungal effects against Fusarium solani by three different fluorescent dyes. Dual staining with propidium iodide (PI) and fluorescein diacetate (FDA) demonstrated high doses of CF66I (120.0 μg ml⁻¹) killed the fungi by acting primarily on the cell membrane. However, at fungistatic concentration (20.0 μg ml⁻¹) of this compound, microscopic observations revealed swelling hyphae with abnormal chitin deposition, as determined by Calcofluor white (CFW) staining, which was indicative of the alterations in cell wall structure. In addition, inhibition of intracellular esterases activity was observed. These results led us to conclude that low doses of CF66I probably inhibited the fungal growth by interfering with the cell metabolic pathways.     

Antioxidant properties of aqueous extracts from red tide plankton cultures

The antioxidant properties of aqueous extracts from the dinophycean flagellates Gymnodinium impudicum and Alexandrium affine and the raphidophycean flagellate Chattonella ovata were examined. An electron spin resonance (ESR)-spin trapping method coupled with steady state kinetic analysis showed that all of the extracts directly scavenge superoxide, and that the superoxide scavenging potential of any of the extracts was comparable to that of L-ascorbic acid. As for hydroxyl radical scavenging, the Fenton reaction and the method of ultraviolet radiation to hydrogen peroxide were used as hydroxyl radical generation systems. All of extracts reduced the level of hydroxyl radicals in both of the systems, indicating that the extracts also directly scavenge hydroxyl radicals. Since the levels of phenolic compounds did not correlate with the antioxidant activities of the extracts, substances other than phenolic compounds also appeared to be attributable to the activities. It is of our interest that the scavenging activities of extract from G. impudicum against superoxide and hydroxyl radicals were increased by heat exposure at 100 degrees C and 200 degrees C respectively. Although the reason for the increased activities of the aqueous extract from G. impudicum is not clear, the heat-resistance of the extract from G. impudicum might make it a desirable antioxidant.     

Sex chromosomes of basal placental mammals

Placental (eutherian) mammals are currently classified into four superordinal clades (Afrotheria, Xenarthra, Laurasiatheria and Supraprimates) of which one, the Afrotheria (a unique lineage of African origin), is generally considered to be basal. Therefore, Afrotheria provide a pivotal evolutionary link for studying fundamental differences between the sex chromosomes of human/mouse (both representatives of Supraprimates and the index species for studies of sex chromosomes) and those of the distantly related marsupials. In this study, we use female fibroblasts to investigate classical features of X chromosome inactivation including replication timing of the X chromosomes and Barr body formation. We also examine LINE-1 accumulation on the X chromosomes of representative afrotherians and look for evidence of a pseudoautosomal region (PAR). Our results demonstrate that asynchronous replication of the X chromosomes is common to Afrotheria, as with other mammals, and Barr body formation is observed across all Placentalia, suggesting that mechanisms controlling this evolved before their radiation. Finally, we provide evidence of a PAR (which marsupials lack) and demonstrate that LINE1 is accumulated on the afrotherian and xenarthran X, although this is probably not due to transposition events in a common ancestor, but rather ongoing selection to retain recently inserted LINE1 on the X.     

Seasonal variation in leaf-litter input and leaf dispersal distances to streams: the effect of converting broadleaf riparian zones to conifer plantations in central Japan

Sugi (Cryptomeria japonica D. Don) is one of the most important evergreen coniferous plantation species in Japan. Much of the riparian forest that was originally dominated by deciduous broadleaf trees has been converted into sugi plantations. The present study investigated the seasonality of leaf-litter input and leaf dispersal to streams to assess the effects of converting riparian forest to sugi plantations. The seasonality of leaf-litter input was assessed at three streams in Nagoya University Forest. At one stream dominated by deciduous broadleaf trees, input was limited to autumn. At two streams in a sugi plantation, input was prolonged from autumn to early spring, and was dominated by sugi needles from winter to early spring. These results suggest that sugi plantations alter the seasonality of leaf-litter input from riparian forests and affect stream ecosystems. Leaf dispersal was assessed by considering the relationship between leaf dispersal distance from three forest layers to the stream and leaf-litter input into two streams. The maximum leaf dispersal distance was 26–28 m for deciduous broadleaf trees from mid-October to November and 10–12 m for sugi needles from December to April. Leaf dispersal distance depended on the tree species. Four species of deciduous broadleaf tree showed greater leaf dispersal than that of sugi. The mean weight of individual sugi needles was higher than that of the broadleaf trees’ leaves, and dispersal depended on strong winds in winter and early spring. Although the leaf dispersal distance from the understory was within 2–4 m, it could be a significant source of leaf-litter input to streams.     

The spatial scale of density-dependent growth and implications for dispersal from nests in juvenile Atlantic salmon

By dispersing from localized aggregations of recruits, individuals may obtain energetic benefits due to reduced experienced density. However, this will depend on the spatial scale over which individuals compete. Here, we quantify this scale for juvenile Atlantic salmon (Salmo salar) following emergence and dispersal from nests. A single nest was placed in each of ten replicate streams during winter, and information on the individual positions (±1 m) and the body sizes of the resulting young-of-the-year (YOY) juveniles was obtained by sampling during the summer. In six of the ten streams, model comparisons suggested that individual body size was most closely related to the density within a mean distance of 11 m (range 2–26 m). A link between body size and density on such a restricted spatial scale suggests that dispersal from nests confers energetic benefits that can counterbalance any survival costs. For the four remaining streams, which had a high abundance of trout and older salmon cohorts, no single spatial scale could best describe the relation between YOY density and body size. Energetic benefits of dispersal associated with reduced local density therefore appear to depend on the abundance of competing cohorts or species, which have spatial distributions that are less predictable in terms of distance from nests. Thus, given a trade-off between costs and benefits associated with dispersal, and variation in benefits among environments, we predict an evolving and/or phenotypically plastic growth rate threshold which determines when an individual decides to disperse from areas of high local density.     

<Emphasis Type="Italic">Chlamydomonas reinhardtii:</Emphasis> duration of its cell cycle and phases at growth rates affected by light intensity

In the cultures of the alga Chlamydomonas reinhardtii, division rhythms of any length from 12 to 75 h were found at a range of different growth rates that were set by the intensity of light as the sole source of energy. The responses to light intensity differed in terms of altered duration of the phase from the beginning of the cell cycle to the commitment to divide, and of the phase after commitment to cell division. The duration of the pre-commitment phase was determined by the time required to attain critical cell size and sufficient energy reserves (starch), and thus was inversely proportional to growth rate. If growth was stopped by interposing a period of darkness, the pre-commitment phase was prolonged corresponding to the duration of the dark interval. The duration of the post-commitment phase, during which the processes leading to cell division occurred, was constant and independent of growth rate (light intensity) in the cells of the same division number, or prolonged with increasing division number. It appeared that different regulatory mechanisms operated through these two phases, both of which were inconsistent with gating of cell division at any constant time interval. No evidence was found to support any hypothetical timer, suggested to be triggered at the time of daughter cell release.     

Does Breeding Ornamentation Signal Genetic Quality in Arctic charr, <Emphasis Type=Italic>Salvelinus alpinus</Emphasis>?

Genetic theories of sexual selection predict that most ornamental secondary sexual traits provide reliable indication of the genetic quality of their bearers. Accordingly, also the offspring of mates with elaborate mating display should perform better than those of less conspicuous counterparts. In this study, we used Arctic charr (Salvelinus alpinus) as a model species to investigate whether the variation in a carotenoid-based red breeding coloration (a sexually dichromatic trait) in different sexes would reflect differences in individual genetic variability, one measure of individual quality, and/or indirectly, be manifested in variation in the offspring’s early viability and growth. We created maternal half-sibling families by artificially fertilizing the eggs with milt from bright- and pale-coloured males and then held the resulting progenies under identical hatchery conditions. The expression of red coloration among parental fish was not associated with their genetic diversity estimates in either sex nor did offspring sired by bright males consistently differ in terms of embryo survival or endogenous growth efficiency from offspring sired by pale males. By contrast, maternal effects were notably strong and, additionally, the degree of female coloration was negatively linked to their reproductive potential. The more intensely coloured females had a smaller relative fecundity and they also produced offspring of lower viability, implying a significant trade-off in resource allocation between ornamentation and offspring. Our results indicate that the red breeding ornamentation of Arctic charr is likely to be informative rather among females than males when the reproductive quality is predicted on grounds of the number of offspring produced. Nevertheless, this study does not support the direct selection hypothesis in explaining the evolution of female ornamentation, but rather suggests that the less intense coloration of female charr compared to males may reflect inter-sexual differences in the trade-off between natural and sexual selection.