Anaerobic ammonia oxidation in a fertilized paddy soil

Evidence for anaerobic ammonium oxidation in a paddy field was obtained in Southern China using an isotope-pairing technique, quantitative PCR assays and 16S rRNA gene clone libraries, along with nutrient profiles of soil cores. A paddy field with a high load of slurry manure as fertilizer was selected for this study and was shown to contain a high amount of ammonium (6.2–178.8 mg kg⁻¹). The anaerobic oxidation of ammonium (anammox) rates in this paddy soil ranged between 0.5 and 2.9 nmolN per gram of soil per hour in different depths of the soil core, and the specific cellular anammox activity observed in batch tests ranged from 2.9 to 21 fmol per cell per day. Anammox contributed 4–37% to soil N2 production, the remainder being due to denitrification. The 16S rRNA gene sequences of surface soil were closely related to the anammox bacteria ‘Kuenenia'', ‘Anammoxoglobus'' and ‘Jettenia''. Most of the anammox 16S rRNA genes retrieved from the deeper soil were affiliated to ‘Brocadia''. The retrieval of mainly bacterial amoA sequences in the upper part of the paddy soil indicated that nitrifying bacteria may be the major source of nitrite for anammox bacteria in the cultivated horizon. In the deeper oxygen-limited parts, only archaeal amoA sequences were found, indicating that archaea may produce nitrite in this part of the soil. It is estimated that a total loss of 76 g N m⁻² per year is linked to anammox in the paddy field.     

Duodenase activates rat peritoneal mast cells via protease-activated receptors of type 1

It was found that duodenase, a serine protease from the bovine duodenum, activates rat peritoneal mast cells (PMC) in vitro presumably via protease-activated receptors (PARs). Like thrombin (a serine protease from the blood coagulation system) and the PAR1 agonist peptide (PAR1-AP), duodenase was shown to accelerate the secretion of β-hexosaminidase (a marker of cell degranulation) by PMC in a dose-dependent manner. The blockage of the proteolytic activity of duodenase toward the substrate Tos-Gly-Pro-Lys-pNA by the soybean Bauman-Birk protease inhibitor substantially reduced (by 40%) the ability of duodenase to stimulate the secretory activity of PMC. Pretreatment of PMC with duodenase decreased the β-hexosaminidase secretion induced by thrombin and PAR1-AP by 35 and 41.7 %, respectively, and abolished the antiinflammatory effect of activated protein C. At the same time, pretreatment of PMC with duodenase did not affect the secretion of β-hexosaminidase induced by compound 48/80, a nonspecific degranulator of mast cells. Duodenase, unlike PAR1-AP (30–100 μM), in a broad concentration range (10–100 nM) did not induce aggregation of human platelets, but suppressed the platelet aggregation elicited by PAR1-AP.     

Biomechanical Energy‐Driven Hybridized Generator as a Universal Portable Power Source for Smart/Wearable Electronics

The fast growth of smart electronics requires novel solutions to power them sustainably. Portable power sources capable of harvesting biomechanical energy are a promising modern approach to reduce battery dependency. Herein, a novel elastic impact‐based nonresonant hybridized generator (EINR‐HG) is reported to effectively harvest biomechanical energy from diverse human activities outdoors. Through the rational integration of a nonlinear electromagnetic generator with two contact‐mode triboelectric nanogenerators, the proposed EINR‐HG generates hybrid electrical output simultaneously under the same mechanical excitations. By introducing a flux‐concentrator with a nanowire‐nanofiber surface modification, significant improvement in the energy harvesting efficiency of the EINR‐HG is achieved. After optimizing using simulations and vibration tests, the as‐fabricated EINR‐HG delivers an outstanding normalized power density of 3.13 mW cm^?3 g^?2 across a matching resistance of 1.5 kΩ at 6 Hz under 1 g acceleration. Under human motion testing, the EINR‐HG generates an optimal output power of 131.4 mW with horizontal handshaking. With a customized power management circuit, the EINR‐HG serves as a universal power source that successfully drives commercial smart electronics, including smart bands and smartphones. This work shows the massive potential of biomechanical energy‐driven hybridized generators for powering personal electronics and portable healthcare monitoring devices.     

Identifying the neural circuitry of alcohol craving and relapse vulnerability

With no further intervention, relapse rates in detoxified alcoholics are high and usually exceed 80% of all detoxified patients. It has been suggested that stress and exposure to priming doses of alcohol and to alcohol-associated stimuli (cues) contribute to the relapse risk after detoxification. This article focuses on neuronal correlates of cue responses in detoxified alcoholics. Current brain imaging studies indicate that dysfunction of dopaminergic, glutamatergic and opioidergic neurotransmission in the brain reward system (ventral striatum including the nucleus accumbens) can be associated with alcohol craving and functional brain activation in neuronal systems that process attentional relevant stimuli, reward expectancy and experience. Increased functional brain activation elicited by such alcohol-associated cues predicted an increased relapse risk, whereas high brain activity elicited by affectively positive stimuli may represent a protective factor and was correlated with a decreased prospective relapse risk. These findings are discussed with respect to psychotherapeutic and pharmacological treatment options.     

<i>In vitro</i> evaluation of antifungal activity of Agave (<i>Agave scabra</i>, Salm Dyck) extracts against post-harvest mushrooms

The agricultural sector, and particularly the horticultural production, has a singular importance in agriculture, considering that it ranks second on agricultural products, nationally and worldwide. Fungal diseases are one of the major causes of vegetable loss during storage, reducing their nutritional value, quality and sale price. Vegetables are usually exposed to diverse treatments with chemical products before storage; as a result, fungal populations develop an increased resistance over time becoming more difficult to control. Because of this, research efforts toward finding more suitable chemicals to control fungal diseases are needed. Natural extracts may be an alternative solve this problem. In the present investigation the fungicidal activity of aqueous and ethanol extracts of Agave scabra was evaluated on the growth of Botrytis cinerea, Mucor sp., Aspergillus niger, Fusarium sp. and Penicillium sp., whose strains were isolated from potato and tomato. To assess their effects, the agar-dilution and agar-well techniques were performed. The ethanol extract was more effective against Botrytis cinerea and Mucor sp. when the agar-well method was used. However, when using the agar-dilution method the ethanol extract of Agave scabra inhibited the growth of Botrytis cinerea, Mucor sp. and Penicillium sp.     

Alpha-thrombin stimulation of heparin secretion by the peritoneal mast cells in rats

The interaction of alpha-thrombin with connective tissue-type mast cells (CTMC) purified by Ficoll density gradient centrifugation has been examined. It was demonstrated that exposure of CTMC to polymixin (widely used histamine liberator) (3 mg/ml) induced the release of heparin and histamine. Exposure of CTMC to 10(-11) M alpha-thrombin resulted in increase of heparin secretion by 75.5% in relation to basal level. CTMC which were stimulated by very low concentrations of alpha-thrombin (10(-11)-10(-8) M) can release high level of heparin, but not histamine. We have a suggestion that the thrombin specificity is connected with the additional recognition binding site for high molecular substrates (HMS) distinct from the active centre. Unlike alpha-thrombin which has both the active centre and the recognition site for HMS, beta/gamma-thrombin with catalytic activity but with disrupted recognition site induced the heparin release from mast cells only at higher concentrations than alpha-thrombin. It was revealed that DIP-alpha-thrombin without proteolytic activity was unable to activate mast cells in contrast to alpha-thrombin. We consider that alpha-thrombin induced release of heparin by CTMC account for proteolytic and hormone-like activity enzyme by means of both the active centre and the additional recognition site for HMS.     

Metal contamination and human health risk associated with the consumption of Labeo rosae from the Olifants River system,South Africa

The Olifants River, a tributary of the Limpopo River system, is one of the most polluted rivers in South Africa. In May 2011 the concentrations of metals in fish muscle tissue from two impoundments, Loskop and Flag Boshielo dams, on the Olifants River were measured and a human health risk assessment conducted to investigate whether it was safe to consume Labeo rosae from these impoundments. Labeo rosae is one of the most common pan fish in these impoundments and is readily available to rural communities. Metals are accumulating in the muscle tissue of L. rosae even although the fish populations appear to be healthy. At Loskop Dam all L. rosae analysed exceeded the recommended hazard quotient (HQ) of 1 for antimony, and less than 50% exceeded that for lead. At Flag Boshielo Dam, the recommended HQ was exceeded for lead in less than 50% of L. rosae analysed, and more than 50% exceeded that for antimony. The weekly consumption of 150?g of L. rosae muscle tissue from these impoundments may pose an unacceptable health risk to rural communities.     

Mast cell population in rats with experimental atherosclerosis

Mast cell population was studied in rats with experimental atherosclerosis. It has been established that animals kept for 8 months on atherogenic diet revealed marked changes in mast cell population. Predominance of light cells and cell defects were noted. Heparin saturation index was reduced (0.35), as compared to the control (3.9). Stimulation of anticoagulation system by DIP-alpha-thrombin in such animals revealed no heparin in the blood. Mast cell subpopulation was characterized by light cell predominance and low heparin saturation index. The nature of cell degradation remained unchanged. The data obtained indicate the defects in mast cell pool in animals with experimental atherosclerosis.     

Comparison of the catalytic properties of alpha- and beta-forms of thrombin

18-25-fold purified alpha-thrombin, having high esterase activity and coagulating ability of 2500 NIH u per 1 mg of protein, was isolated using chromatography of commercial thrombin through SP-Sephadex C-50. Limited proteolysis of alpha-thrombin on the column with immobilized trypsin resulted in the appearance of beta-thrombin with alpha-thrombin-like esterase activity and tracing coagulating activity (2-5 NIH u per 1 mg of protein). Molecular weight analysis of alpha- and beta-thrombin forms suggests that a peptide (or peptides) with Mr of 1100 is splitted off under proteolysis. Some similarity is revealed in kinetic parameters (Km(app) and kkat) of TAME and BAME hydrolysis by alpha- and beta-thrombin, although Km(app) is somewhat low (approximately 2-fold) for alpha-thrombin. Investigation of TAME hydrolysis kinetics by both thrombin forms at a wide range of substrate concentrations has revealed the effect of substrate activation. Kinetic constants Ks and beta for high substrate concentrations are calculated. It is suggested that the similarity of alpha- and beta-thrombin action on arginine esters and sharp differences in their effect on fibrinogen may be a result of a disturbance of substrate-binding region of beta-thrombin active site.