Treatment of landfill leachate using UASB-MBR-SHARON–Anammox configuration

Leachate treatment is a challenging issue due to its high pollutant loads. There are several studies on feasible treatment methods of leachate. In the scope of this study, high organic content of young leachate was eliminated using an upflow anaerobic sludge blanket (UASB) and a membrane bioreactor (MBR) in sequence and effluent of the system was given to single reactor for high activity ammonia removal over nitrite (SHARON) and anaerobic ammonia oxidation (Anammox) reactors to remove nitrogen content. All reactors were set up at lab scale in order to evaluate the usage of these processes in sequencing order for leachate treatment. COD and TKN removal efficiencies were over 90 % in the combined processes which were operated during the study. The biodegradable portion of organic matter was removed with an efficiency of 99 %. BOD₅ concentration decreased to 50 mg/L by UASB and MBR in sequence even the influent BOD₅ concentration was over 8,000 mg/L. Although high nitrogen concentrations were observed in raw leachate, successful removal of nitrogen was accomplished by consecutive operations of SHARON and Anammox reactors. The results of this study demonstrated that with an efficient pretreatment of leachate, the combination of SHARON–Anammox processes is an effective method for the treatment of high nitrogen content in leachate.     

Convergent evolution of floral signals underlies the success of Neotropical orchids

The great majority of plant species in the tropics require animals to achieve pollination, but the exact role of floral signals in attraction of animal pollinators is often debated. Many plants provide a floral reward to attract a guild of pollinators, and it has been proposed that floral signals of non-rewarding species may converge on those of rewarding species to exploit the relationship of the latter with their pollinators. In the orchid family (Orchidaceae), pollination is almost universally animal-mediated, but a third of species provide no floral reward, which suggests that deceptive pollination mechanisms are prevalent. Here, we examine floral colour and shape convergence in Neotropical plant communities, focusing on certain food-deceptive Oncidiinae orchids (e.g. Trichocentrum ascendens and Oncidium nebulosum) and rewarding species of Malpighiaceae. We show that the species from these two distantly related families are often more similar in floral colour and shape than expected by chance and propose that a system of multifarious floral mimicry—a form of Batesian mimicry that involves multiple models and is more complex than a simple one model–one mimic system—operates in these orchids. The same mimetic pollination system has evolved at least 14 times within the species-rich Oncidiinae throughout the Neotropics. These results help explain the extraordinary diversification of Neotropical orchids and highlight the complexity of plant–animal interactions.     

Effect of some analgesics on Paraoxonase-1 purified from human serum

The in vitro effects of the analgesic drugs, lornoxicam, indomethacin, tenoxicam, diclofenac sodium, ketoprofen and lincomycine, on the activity of purified human serum paraoxonase (hPON1) (EC 3.1.8.1.) were evaluated. hPON1 was purified from human serum with a final specific activity of 3840 U mg^?1 and a purity of 25.3 % using simple chromatographic methods, including DEAE-Sephadex anion exchange and Sepharose 4B-L-tyrozine-1-napthylamine hydrophobic interaction chromatography. SDS-polyacrylamide gel electrophoresis indicated a single protein band corresponding to hPON1. The six analgesics dose-dependently decreased in vitro hPON1 activity, with IC₅₀ values for lornoxicam, indomethacin, tenoxicam, diclofenac sodium, ketoprofen and lincomycine of 0.136, 0.195, 0.340, 1.639, 6.23 and 9.638 mM, respectively. K_i constants were 0.009, 0.097, 0.306, 0.805, 13.010 and 11.116 mM, respectively. Analgesics showed different inhibition mechanisms: lornoxicam, diclofenac sodium and lincomycine were uncompetitive, indomethacin and tenoxicam were competitive, ketoprofen was noncompetitive. According to the results, inhibition potency was lornoxicam>indomethacin>tenoxicam> diclofenac sodium>ketoprofen> lincomycine.     

A novel spectrofluorimetric method for the determination of calcitonin in ampules through derivatization with fluorescamine

In this study, a simple, sensitive and selective spectroflourimetric method has been developed for the determination of salmon calcitonin (sCT) in ampules. The method is based on the reaction between sCT and fluorescamine at pH 8.5 in borate buffer, resulting in a highly fluorescent derivative. Fluorescence of derivatized sCT solutions was measured by setting the excitation and emission monochromators and slit widths to 390, 484 and 10 nm, respectively. Sevaral derivatization parameters were optimized. A calibration graph was constructed using standard solutions of the derivatized calcitonin in the range 0.5–6.0 µg/mL. Limit of detection and limit of quantification values were determined to be 0.124 and 0.372 µg/mL, respectively. The proposed method was successfully applied for the determination of sCT in commercially available ampules. High recovery values (101.0–102.0 %), and a low relative standard deviation (RSD %) value (5.3–5.4) proved the accuracy and precision of the proposed method. An isocratic reversed‐phase high‐performance liquid chromatographic (HPLC) method, as a reference, was also developed for the determination of sCT. A reversed‐phase Nucleosil® C₁₈ column (250 mm × 4.6 mm i.d., 10 µm particle size, 120 Å pore size) was used and the detector was set at 210 nm. Statistical comparison of the results of the two methods showed clearly that there was no significant difference between them. Copyright © 2012 John Wiley & Sons, Ltd.     

Protein folding at single-molecule resolution

The protein folding reaction carries great significance for cellular function and hence continues to be the research focus of a large interdisciplinary protein science community. Single-molecule methods are providing new and powerful tools for dissecting the mechanisms of this complex process by virtue of their ability to provide views of protein structure and dynamics without associated ensemble averaging. This review briefly introduces common FRET and force methods, and then explores several areas of protein folding where single-molecule experiments have yielded insights. These include exciting new information about folding landscapes, dynamics, intermediates, unfolded ensembles, intrinsically disordered proteins, assisted folding and biomechanical unfolding. Emerging and future work is expected to include advances in single-molecule techniques aimed at such investigations, and increasing work on more complex systems from both the physics and biology standpoints, including folding and dynamics of systems of interacting proteins and of proteins in cells and organisms. This article is part of a Special Issue entitled: Protein Dynamics: Experimental and Computational Approaches.     

Effects of a modified zeolite on P and N processes and fluxes across the lake sediment–water interface using core incubations

A new locally produced P-inactivation agent, Z2G1, was tested on sediment cores from Lake Okaro, New Zealand, for phosphorus (P) removal efficacy and any non-target side effects prior to a whole lake trial to manage internal P loading. Z2G1 is a granular product which settles rapidly, and was designed as a sediment capping material. It is a modified zeolite which acts as a carrier for the aluminium (Al)-based P-binding agent. It was found to have a high affinity for P and did not release Al into the water column. Continuous-flow incubation study results showed that a thin layer of Z2G1 (~2 mm) could completely block the release of P from the sediment under aerobic and anoxic conditions, and remove P from the overlying water in contact with the capping layer. The Z2G1 capping layer neither released metals itself nor did it induce the release of metals from the sediments, and the zeolite substrate absorbed arsenic and mercury from the geothermally influenced Lake Okaro sediments. In general, zeolites are strong cation absorbers and the zeolite substrate of Z2G1 absorbed ammoniacal nitrogen, making it the only sediment capping material to actively remove both P and N. There were, however, indications of a suppression effect on microbial denitrification by the Z2G1 capping layer under aerobic conditions. Overall, the Z2G1 sediment capping material is a highly effective P-inactivation agent which might be a useful material for managing internal P loads in eutrophic lakes.     

Cytotoxic and haemolytic steroidal glycosides from the Caribbean sponge Pandaros acanthifolium

Six new steroidal saponins, pandarosides K–M (1–3) and their methyl esters (4–6), were isolated as minor components, after a careful chemical reinvestigation of the Caribbean sponge Pandaros acanthifolium. Their structures were established on the basis of spectroscopic analyses and comparison with the data obtained from previous metabolites of this family. All new compounds showed moderate to weak activity against four parasitic protozoa. Additionally, these compounds and previously reported pandarosides and acanthifoliosides were tested on three human tumour cell lines, and their haemolytic and liposome permeabilizing activity were assessed. Two pandarosides exhibited moderate to strong cytotoxic effect, while three acanthifoliosides showed strong haemolytic activity.     

Hunger states switch a flip-flop memory circuit via a synaptic AMPK-dependent positive feedback loop

Synaptic plasticity in response to changes in physiologic state is coordinated by hormonal signals across multiple neuronal cell types. Here, we combine cell-type-specific electrophysiological, pharmacological, and optogenetic techniques to dissect neural circuits and molecular pathways controlling synaptic plasticity onto AGRP neurons, a population that regulates feeding. We find that food deprivation elevates excitatory synaptic input, which is mediated by a presynaptic positive feedback loop involving AMP-activated protein kinase. Potentiation of glutamate release was triggered by the orexigenic hormone ghrelin and exhibited hysteresis, persisting for hours after ghrelin removal. Persistent activity was reversed by the anorexigenic hormone leptin, and optogenetic photostimulation demonstrated involvement of opioid release from POMC neurons. Based on these experiments, we propose a memory storage device for physiological state constructed from bistable synapses that are flipped between two sustained activity states by transient exposure to hormones signaling energy levels.     

The first report described as an important study: The association of mannose-binding lectin gene 2 polymorphisms in children with Down syndrome

BACKGROUND:

Mannose-binding lectin gene 2 (MBL2) plays a very important role in the first line of host immune response in Down syndrome (DS). The importance of MBL2 gene polymorphisms in children with DS is unclear, and no research has addressed MBL2 gene polymorphisms in patients with DS. This is the first report describing an important association between MBL2 gene polymorphisms and infections in children with DS.

MATERIALS AND METHODS:

We compared the frequency of single-nucleotide polymorphisms (SNPs) at two codons of the MBL2 gene in a cross sectional cohort of 166 children with DS and 229 controls. Polymorphisms at codons 54 (GGC→GAC) and 57 (GGA→GAA) in exon 1 of the MBL2 gene were typed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique using the restriction enzymes BshN1 (derivated from Bacillus sphaericus) and MboII (derivated from Moraxella bovis), respectively.

RESULTS:

MBL2 codon 54 GA genotype frequency was found to be lower in patients with DS (22.9%) than those of healthy controls (35.8%), differences were statistically significant (OR = 0.532, 95% CI = 0.339-0.836, P = 0.008). On the other hand, codon 57 polymorphism in the MBL2 gene was detected in none of the DS patients, but only one person in the control group showed codon 57 GA genotype (OR = 1.004, 95% CI = 0.996-1.013, P = 1.000).

CONCLUSION:

Our data provides an evidence for the first time that a homozygote or heterozygote for the variant, MBL2 alleles, is not associated with infections in patients with DS, and do not influence the incidence of infections.