The bacterial communities of bioelectrochemical systems associated with the sulfate removal under different pHs

Sulfate contamination in ecosystems has been a serious problem. Among various technologies, bioelectrochemical systems (BESs) show the advantage of no-pollution and low-cost for removing sulfate. In order to further expound the biological process of sulfate removal in BESs, 454 pyrosequencing was applied to analyze the bacterial communities under different pH conditions. The bacterial community profiles were analyzed from three aspects: (a) the α-diversity and β-diversity of bacterial communities, (b) the distribution of bacterial phylotypes, and (c) the characterizations of dominant operational taxonomic units (OTUs). We demonstrated that the indexes of phylotype richness and phylogenetic diversity were positively correlated across the pH gradient in the BESs. Among the dominant OTUs, the OTUs which were highly similar to Desulfatirhabdium butyrativorans, Desulfovibrio marrakechensis and Desulfomicrobium sp. might participate in removing sulfate. Standing on genus level, Desulfomicrobium and Sulfuricurvum play conducing and adverse roles for sulfate removal in alkaline condition, respectively. Desulfovibrio contributed to removing sulfate in the neutral and acidic conditions, while Thiomonas mainly weakened the performance of sulfate removal in neutral pH condition. These results further clarified how pH condition directly affected the bacterial communities, which consequently affected the performance of sulfate pollutant treatment using BESs.     

Evaluation of pilot-scale modified A2O processes for the removal of nitrogen compounds from sewage

In this study, pilot-scale experiments for the removal of nitrogen from sewage obtained from a county Y sewer system were performed using modified A₂O processes. Using this approach, the total amount of nitrogen discharged during denitrification of the influent was average 38.6 mg/L and a level of average 10.8 mg/L was maintained throughout the denitrification process, which resulted in an average removal efficiency that was greater than 72%. The nitrogen components in the effluent water consisted of 22% ammonia nitrogen, 6% nitrite nitrogen and 72% nitrate nitrogen, reaching a nitrification efficiency of 94%. In conclusion, since these advanced treatment methods, which involve modified A₂O processes, were successfully employed to remove nitrogen from sewage discharge, they hold promise for wide spread use by treatment plants.     

Enhanced lymph node retention of subcutaneously injected IgG1-PEG2000-liposomes through pentameric IgM antibody-mediated vesicular aggregation

An efficient strategy for enhancing the lymph node deposition of rapidly drained liposomes from the interstitial injection site is described. Subcutaneously injected small-sized immuno-poly(ethyleneglycol)-liposomes (immuno-PEG-liposomes), containing 10 mol% mPEG₃₅₀-phospholipid and 1 mol% PEG₂₀₀₀-phospholipid in their bilayer and where IgG1 is coupled to the distal end of PEG₂₀₀₀, not only drain rapidly from the interstitial spaces into the initial lymphatic system, but also accumulate efficiently among the lymph nodes draining the region when compared with non-PEG-bearing immunoliposomes where IgG is directly coupled to the phospholipid. Liposome deposition among the draining lymph nodes, however, was further enhanced dramatically following an adjacent subcutaneous injection of a pentameric IgM against the surface attached IgG molecules (IgM:IgG, 10:1) without compromising vesicle drainage from the interstitium. This is suggested to arise either as a result of formation of large immuno-aggregates within the lymphatic vessels with subsequent transport to and trapping among the regional lymph nodes and/or following IgM binding to Fc receptors of the lymph node sinus macrophages forming a platform for subsequent trapping of drained IgG-coupled liposomes. This lymph node targeting approach may be amenable for the design and surface engineering of any rapidly drained nanoparticulate system bearing peptides and proteins that can be aggregated with a desired monoclonal pentameric IgM.     

Hunting of Mammals Reduces Seed Removal and Dispersal of the Afrotropical Tree Antrocaryon klaineanum (Anacardiaceae)

Throughout the tropics, mammalian seed dispersers are being driven to local extinction by intense hunting pressure, generating concern not only about the loss of these species, but also about the consequences for the plants they disperse. We compared two rain forest sites in Cameroon—one with heavy hunting pressure and one protected from hunting—to appraise the loss of mammalian seed dispersers and to assess the impact of this loss on seed removal and seed dispersal of Antrocaryon klaineanum (Anacardiaceae), a mammal-dispersed tree. Surveys of arboreal frugivores indicate that three of the five monkey species, as well as chimpanzee and gorilla, have been extirpated from the hunted forest. Diaspore counts underneath A. klaineanum adults (six trees per site) indicate that seed removal is severely reduced in the hunted forest. Finally, genetic maternity exclusion analysis (using 3–7 nuclear microsatellite loci) of maternally inherited endocarp tissue from diaspores collected under the canopies of 12 fruiting "mother" trees (six trees per site) revealed that seed dispersal in the hunted forest is also greatly reduced. In the hunted forest with reduced mammal dispersal agents, only 1 of the 53 assayed endocarps (2%) did not match the mother and was determined to be from a dispersed diaspore. By contrast, in the protected forest, 20 of the 48 assayed endocarps (42%) were from dispersed diaspores. This study provides strong evidence that loss of dispersal agents can lead to reduced seed removal and loss of seed dispersal, disrupting the seed dispersal cycle.     

Copper removal by immobilized Microcystis aeruginosa in continuous flow columns at different bed heights: study of the adsorption/desorption cycle

Microcystis aeruginosa immobilized in a natural polymer was tested for its potential to remove Cu²⁺ ions from aqueous solution in a continuous, downflow packed columnar reactor. Various parameters like flow rate, bed height and contact time required for maximum removal of test metals by the immobilized Microcystis aeruginosa were optimized. An increase in bed height from 2 to 10 cm resulted in an apparent decrease in biosorption capacity from 8.94 to 5.34 mg g^–1, but more Cu²⁺ solution was purified at the higher bed height. Efficiency of metal recovery from Cu²⁺-loaded biomass and its subsequent regeneration was also determined. Immobilized M. aeruginosa was found to be effective in Cu²⁺ removal from solution for up to 10 cycles of adsorption–desorption and 1 M HCl is very efficient desorbent for regeneration of Microcystis biomass for reuse.     

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.     

Kidney proteome responses in the teleost fish Paralichthys olivaceus indicate a putative immune response against Streptococcus parauberis

The proteomic response to bacterial infection in a teleost fish (Paralichthys olivaceus) infected with Streptococcus parauberis was analyzed using label-free protein quantitation coupled with LC-MS(E) tandem mass spectrometry. A total of 82 proteins from whole kidney, a major lymphoid organ in this fish, were found to be differentially expressed between healthy and diseased fish analyzed 6, 24, 72 and 120 h post-infection. Among the differentially expressed proteins, those involved in mediating immune responses (e.g., heat shock proteins, cathepsins, goose-type lysozyme and complement components) were most significantly up-regulated by infection. In addition, cell division cycle 48 (CDC48) and calreticulin, which are associated with cellular recovery and glycoprotein synthesis, were up-regulated in the universal protein group, whereas the other proteins in that group were down-regulated. There was continuous activation of expression of immune-associated proteins during infection, but there was also loss of expression of proteins not involved in immune function. We expect that our findings regarding immune response at the protein level would offer new insight into the systemic response to bacterial infection of a major immune organ in teleost fish.     

Environmental restoration effects of Ranunculus sceleratus L. in a eutrophic sewage system

This study investigated the environmental restoration effects of Ranunculus sceleratus in a sewage system microcosm trial, including the removal of pollutants and algal inhibition. We compared the removal of pollutants by R. sceleratus in a eutrophic sewage system in the presence and the absence of algae. The rate of removal without algae was 16.2–20.5% of that with algae. ${\text{NH}}_4^{+}–\text{N}$ was removed most readily by R. sceleratus. The effects of R. sceleratus on the growth of Microcystis aeruginosa were also investigated in two allelopathic modes. The level of algal inhibition after the addition of an extract of Ranunculus scleratus was 57.1–78.9% greater than that in a co-culture test. To understand the role of allelopathy interference with algal development, we also determined the total flavonoid contents of plants, which ranged from 3.57 g to 20.19 g per plant. The cell density of Microcystis aeruginosa was negatively correlated with the total flavonoids in R. sceleratus, although aquatic macrophytes may contain other allelochemicals involved with algal inhibition in addition to flavonoid compounds. The environmental effects of R. sceleratus were significantly correlated with its growth stage (or water retention time), plant height, and biomass. This study suggests that R. sceleratus has potential for the low-effort and sustainable management of freshwaters, particularly the removal of nutrient pollutants and the reduction of excessive algal growth, which may be attributable to allelochemicals such as flavonoids. The in situ environmental restoration effects of R. sceleratus require further investigation at the ecosystem level.     

Sperm displacement behavior of the cuttlefish Sepia esculenta (Cephalopoda: Sepiidae)

Sperm displacement behavior of cuttlefish (Sepia esculenta) was observed in a tank. Before ejaculation, male cuttlefish used their arms III to scrape out sperm masses attached to the buccal membranes of females. The removed sperm mass debris was directly visible and countable. Active sperm were present within the removed sperm debris, implying that the aim of this behavior is to remove competing male sperm. However, many sperm masses remained on the female buccal membrane even after the removal behavior, showing that sperm removal in S. esculenta is incomplete. The duration of sperm removal (an indicator of male investment in that process) was unaffected by the body sizes of mated pair, the duration of spermatangia placement at the current mating (for the hypothesis that the sperm removal serves to creat attachment space of spermatophores), or the estimated amount of sperm masses deposited from previous matings. Moreover, male S. esculenta performed sperm removal regardless of whether the last male to mate with the partner was himself, suggesting males remove not only the sperm of rivals but also their own. Although the number of removed sperm masses increased with the time spent on removal of sperm, male cuttlefish may shorten the duration of sperm removal to avoid the risk of mating interruption. We conclude that this time restriction would likely influence the degree of partial sperm removal in S. esculenta. A digital video image relating to the article is available at .This revised version was published online in April 2005 with corrections in the abstract.