Biological sulphate reduction and redox mediator effects on azo dye decolourisation in anaerobic–aerobic sequencing batch reactors

In this work, the anaerobic period of an anaerobic–aerobic sequencing batch reactor was found to allow the reductive decolourisation of azo dyes. 1-l reactors were operated in 24-h cycles comprising anaerobic and aerobic reaction phases, fed with a simulated textile effluent including a reactive type (Remazol Brilliant Violet 5R) or an acid type (Acid Orange 7) azo dye. The aim was to assess the role of different redox phenomena in the anaerobic decolourisation process. Selective inhibition of sulphate reducing bacteria was carried out in the sulphate-containing, reactive dye fed reactor, resulting in nearly complete, though reversible and inhibition of decolourisation. The acid dye fed reactor's supplementation with sulphate, though resulting in sulphate reduction, did not improve decolourisation. Other redox mediators, namely quinones, were more effective in promoting electron transfer to the azo bond. Bio-augmentation of the acid dye fed reactor with a pure sulphate reducer strain known to decolourise azo dyes, Desulfovibrio alaskensis, was also carried out. Decolourisation was improved, but apparently as a result of the carbon source change required to support D. alaskensis growth. A chemically mediated reduction of the azo bond coupled to biological sulphate reduction, thus seemed to account for the high decolourisation yields of both dyes.     

Amylose–dye complexes in cationic micelles: an optical spectroscopy study

The formation of amylose complexes with rose bengal (RB), erythrosine B (ER), and phenolphthalein (PP) in the presence of the cationic detergent tetradecyltrimethylammonium bromide (TTABr) was studied using optical spectroscopy methods. Absorption spectroscopy, steady-state fluorescence spectroscopy and picosecond time-resolved fluorescence spectroscopy were used to derive association constants k_s of the dyes, critical micelle concentration (CMC) values and structural information on the complexes formed. It seems that PP fits very well into amylose sites, where it forms an efficient inclusion complex with k_s=44,500 M⁻¹. The molecular diameter of RB is too big to fit the amylose cavity. Only part of the xanthene unit may be adopted in the helical cavity of amylose, whereas most of the interaction occurs through electrostatic and/or dipole–dipole interactions with the amylose chain. The ER molecule is an intermediate case, because it may fit the amylose cavity or adsorb on the amylose surface to form a complex. The presence of a surfactant in the amylose–ligand system increases the association constant for all dyes. In the presence of amylose, a decrease of the detergent CMC value of about one order of magnitude is observed. It is probable that the increased number of micelles incorporate more dyes into the amylose vicinity, which finally changes the structure of the amylose chain. On a macro scale, it was noted that the samples with dyes and detergent have a lower tendency to precipitate and the gelation process is delayed compared to that in water.     

Decolorization of anthraquinone dye intermediate and its accelerating effect on reduction of azo acid dyes by Sphingomonas xenophaga in anaerobic–aerobic process

Decolorization of 1-aminoanthraquinone-2-sulfonic acid (ASA-2) and its accelerating effect on the reduction of azo acid dyes by Sphingomonas xenophaga QYY were investigated. The study showed that ASA-2 could be efficiently decolorized by strain QYY under aerobic conditions according to the analysis of total organic carbon removal and UV-VIS spectra changes. Moreover, strain QYY was able to reduce azo acid dyes under anaerobic conditions. The effects of various operating conditions such as carbon sources, temperature, and pH on the reduction rate were studied. It was demonstrated that ASA-2 used as a redox mediator could accelerate the reduction process. Consequently the reduction of azo acid dyes mediated by ASA-2 and the decolorization of ASA-2 with strain QYY could be achieved in an anaerobic-aerobic process.     

Is Congo red an amyloid-specific dye?

Congo red (CR) binding, monitored by characteristic yellow-green birefringence under crossed polarization has been used as a diagnostic test for the presence of amyloid in tissue sections for several decades. This assay is also widely used for the characterization of in vitro amyloid fibrils. In order to probe the structural specificity of Congo red binding to amyloid fibrils we have used an induced circular dichroism (CD) assay. Amyloid fibrils from insulin and the variable domain of Ig light chain demonstrate induced CD spectra upon binding to Congo red. Surprisingly, the native conformations of insulin and Ig light chain also induced Congo red circular dichroism, but with different spectral shapes than those from fibrils. In fact, a wide variety of native proteins exhibited induced CR circular dichroism indicating that CR bound to representative proteins from different classes of secondary structure such as alpha (citrate synthase), alpha + beta (lysozyme), beta (concavalin A), and parallel beta-helical proteins (pectate lyase). Partially folded intermediates of apomyoglobin induced different Congo red CD bands than the corresponding native conformation, however, no induced CD bands were observed with unfolded protein. Congo red was also found to induce oligomerization of native proteins, as demonstrated by covalent cross-linking and small angle x-ray scattering. Our data suggest that Congo red is sandwiched between two protein molecules causing protein oligomerization. The fact that Congo red binds to native, partially folded conformations and amyloid fibrils of several proteins shows that it must be used with caution as a diagnostic test for the presence of amyloid fibrils in vitro.     

Development of sustainable dye adsorption system using nutraceutical industrial fennel seed spent—studies using Congo red dye

Fennel seed spent (FSS)—an inexpensive nutraceutical industrial spent has been used as an efficient biosorbent for the removal of Congo red (CR) from aqueous media. Results show that the conditions for maximum adsorption would be pH 2-4 and 30°C were ideal for maximum adsorption. Based on regression fitting of the data, it was determined that the Sips isotherm (R² = 0.994, χ² = 0.5) adequately described the mechanism of adsorption, suggesting that the adsorption occurs homogeneously with favorable interaction between layers with favorable interaction between layers. Thermodynamic analysis showed that the adsorption is favorable (negative values for ΔG°) and endothermic (ΔH° = 12–20 kJ mol^?1) for initial dye concentrations of 25, 50, and 100 ppm. The low ΔH° value indicates that the adsorption is a physical process involving weak chemical interactions like hydrogen bonds and van der Waals interactions. The kinetics revealed that the adsorption process showed pseudo-second-order tendencies with the equal influence of intraparticle as well as film diffusion. The scanning electron microscopy images of FSS show a highly fibrous matrix with a hierarchical porous structure. The Fourier transform infrared spectroscopy analysis of the spent confirmed the presence of cellulosic and lignocellulosic matter, giving it both hydrophilic and hydrophobic properties. The investigations indicate that FSS is a cost-effective and efficient biosorbent for the remediation of toxic CR dye.     

Studies on α-Glucosidase in Rice

Two kinds of αglucosidase which were homogeneous in disc electrophoretic and ultra-centrifugal analysis were isolated from rice seeds by means of ammonium sulfate fractionation and CM-cellulose, Sephadex G–100 and DEAE-cellulose column chromatography and designated as α-glucosidase I and α-glucosidase II.

Both α-glucosidases hydrolyzed maltose and soluble starch to glucose and showed same optimal pH (4.0) on the both substrates. In addition, both enzymes acted on various α-linked gluco-oligosaccharides and soluble starch but little or not on α-linked hetero-glucosides and α-l,6-glucan (dextran).

Activity of the enzymes on maltose and soluble starch was inhibited by Tris and erythritol. α-Glucosidase II was more sensitive to the inhibitors than α-glucosidase I.

Km value for maltose was 1.1 mM for α-glucosidase I and 2.0 mM for α-glucosidase II.     

Homing in on intracellular Abeta?

In this issue of Neuron, a study by Billings et al. points to intracellular Abeta as a possible cause of neuronal dysfunction. In a mouse model of Alzheimer's disease, Billings et al. link appearance of intraneuronal Abeta to cognitive impairments and then show that "clearance" of intraneuronal Abeta by anti-Abeta antibodies restores cognitive deficits.     

Decolorization of azo dye by immobilized Pseudomonas luteola entrapped in alginate–silicate sol–gel beads

Pseudomonas luteola was immobilized by entrapment in alginate–silicate sol–gel beads for decolorization of the azo dye, Reactive Red 22. The influences of biomass loading and operating conditions on specific decolorization rate and dye removal efficiency were studied in details. The immobilized cells were found to be less sensitive to changes in agitation rates (dissolved oxygen levels) and pH values. Michaelis–Menten kinetics could be used to describe the decolorization kinetics with the kinetic parameters being 36.5 mg g⁻¹ h⁻¹, 300.1 mg l⁻¹ and 18.2 mg g⁻¹ h⁻¹, 449.8 mg l⁻¹ for free and immobilized cells, respectively. After five repeated batch cycles, the decolorization rate of the free cells decreased by nearly 54%, while immobilized cells still retained 82% of their original activity. The immobilized cells exhibited better thermal stability during storage and reaction when compared with free cells. From SEM observation, a dense silicate gel layer was found to surround the macroporous alginate–silicate core, which resulted in much improved mechanical stability over that of alginate beads when tested under shaking conditions. Alginate–silicate matrices appeared to be the best matrix for immobilization of P. luteola in decolorization of Reactive Red 22 when compared with previous results using synthetic or natural polymer matrices.     

Are Phragmites australis enzymes involved in the degradation of the textile azo dye acid orange 7?

The role of antioxidant and detoxification enzymes of Phragmites australis, in the degradation of an azo dye, acid orange 7 (AO7), was studied. Activities of several enzymes involved in plant protection against stress were assayed through the activity characterization of superoxide dismutase (SOD), peroxidases (POD), catalase (CAT), ascorbate peroxidase (APOX), dehydroascorbate reductase (DHAR) and glutathione S-transferase (GST), obtained from P. australis crude extracts of leaves, stems and roots. A sub-surface vertical flow constructed wetland, planted with P. australis was used to test the plants response to the AO7 exposure at two different concentrations (130 and 700 mg l(-1)). An activity increase was detected for an AO7 concentration of 130 mg l(-1) for most enzymes studied (SOD, CAT and APOX), especially in leaves, suggesting a response of the reactive oxygen species scavenging enzymes to the chemical stress imposed. GST activity increase in this situation can also be interpreted as an activation of the detoxification pathway and subsequent AO7 conjugation. A totally different behaviour was observed for AO7 at 700 mg l(-1). An evident decrease in activity was observed for SOD, CAT, APOX and GST, probably due to enzymatic inhibition by AO7. Contrarily, DHAR activity augmented drastically in this situation. POD activity was not greatly affected during trial. Altogether these results suggest that P. australis effectively uses the ascorbate-glutathione pathway for the detoxification of AO7.     

Studies on the Flavors in Saké

A very small amount of vanillin was found in Saké, but the mechanism of its formation during Saké brewing has not yet been elucidated. Therefore, shaking culture of a Saké yeast (Kyokai No. 7 strain) was carried out in the Hayduck’s solution containing ferulic acid which was considered to be a precursor of vanillin. By the analysis of the fermentation products, formation of p-hydroxybenzoic acid and vanillic acid was elucidated. On the other hand, in the similar experiment using vanillin in place of ferulic acid, p-hydroxybenzoic acid, p-hydroxybenzaldehyde and vanillic acid were identified.

On these results, it was suggested that vanillin might be formed as an intermediate of the degradation reaction of ferulic acid, and also, the demethoxylation of vanillin might be occurred in the fermentation of yeast.     

Direct Interference on Competition in a Chemostat

Thispaperstudiestheglobaldynamicsofcompetitioninchemostatinwhichtwopopulationsofmicrooganismscompeteexploitativelyforasingle,essential,nonreproducing,growth-limitingsubstrateandthereisadirectinterferencebetweencompetitors.Inordertounderstandthedifferencesintheeffectsofintraspecificandinterspecificinterference,thebothcasesareconsideredrespectively.Keywords:##4Populationdynamicsecology;;chemostat;;competition;;interference;;interspecific;;intraspecific;;principalofcompetitiveexclusion     

Studies on 5′-Phosphodiesterases in Microorganisms

5′-Phosphodiesterase, which degrades RNA into nucleoside-5′-monophosphates but does not attack DNA, is present not only in mycelium but also in culture filtrate of Penicillium citrinum Thorn 1131. For the formation of this enzyme pH of the culture medium must be kept below 7.0 during culture, as this enzyme is inactivated rapidly in alkaline solution. The pH optimum of this enzyme is in the region of pH 5. Cysteine, Mg⁺⁺, sodium fluoride, and inorganic ortho- or pyrophosphate are without appreciable effect on this enzyme. Nucleoside-5′-monophosphates, which have been regarded as new chemical seasonings, can be produced economically in a large scale by using the microbial 5′-phosphodiesterase.     

Governmental policies on HIV infection in China

This article is a general review of the evolvement of HIV/AIDS-related public policies in China since 1980＇s. It tracks the important laws, regulations and other governmental documents in regard to HIV/AIDS prevention mainly at central level.     

Benefits in Cash or in Kind? A Community Consultation on Types of Benefits in Health Research on the Kenyan Coast

BackgroundProviding benefits and payments to participants in health research, either in cash or in kind, is a common but ethically controversial practice. While much literature has concentrated on appropriate levels of benefits or payments, this paper focuses on less well explored ethical issues around the nature of study benefits, drawing on views of community members living close to an international health research centre in Kenya.MethodsThe consultation, including 90 residents purposively chosen to reflect diversity, used a two-stage deliberative process. Five half-day workshops were each followed by between two and four small group discussions, within a two week period (total 16 groups). During workshops and small groups, facilitators used participatory methods to share information, and promote reflection and debate on ethical issues around types of benefits, including cash, goods, medical and community benefits. Data from workshop and field notes, and voice recordings of small group discussions, were managed using Nvivo 10 and analysed using a Framework Analysis approach.

Findings and Conclusions

The methods generated in-depth discussion with high levels of engagement. Particularly for the most-poor, under-compensation of time in research carries risks of serious harm. Cash payments may best support compensation of costs experienced; while highly valued, goods and medical benefits may be more appropriate as an ‘appreciation’ or incentive for participation. Community benefits were seen as important in supporting but not replacing individual-level benefits, and in building trust in researcher-community relations. Cash payments were seen to have higher risks of undue inducement, commercialising relationships and generating family conflicts than other benefits, particularly where payments are high. Researchers should consider and account for burdens families may experience when children are involved in research. Careful context-specific research planning and skilled and consistent communication about study benefits and payments are important, including in mitigating potential negative effects.     

Growth in Crustacea – twenty years on

Developments during the past 20 years are reviewed for four aspects of crustacean growth. These are the hormonal control of moulting, the effects of external factors on growth rate, the patterns of growth and the determination of age. Hormonal control. The nature and structure of Moult Inhibiting Hormone has been determined, though the mechanism by which it inhibits crustecdysone production is still unclear. A role in moult control by Crustacean Hyperglycaemic Hormone has been demonstrated, but needs clarification. Methyl farnesoate, a juvenile hormone like substance, occurs in Crustacea: however, a clear function as a juvenile hormone has yet to be shown. External factors. The effect of increased temperature in reducing moult increments is supported by further data. Reduced food supply causes smaller moult increments and longer intermoult periods: the latter effect is generally proportionately greater. A role for CHH in this process is hypothesised. Patterns of growth. Little advance has occurred in understanding the rationale for the diversity of growth patterns. Computer modelling offers promise, but is constrained by lack of data on natural mortality for validation. Determination of age. The basic methods available remain size frequency analysis and tagging programmes. There have been advances in technology and methods of analysis, but no major breakthrough. Novel methods include radionuclide ratios (expensive, complex and give only duration of current intermoult), lipofuschin pigment assay (promising, but needs further validation), and annular structures in the infra-cerebral organ (still very speculative).     

Living on the edge – The predicted impact of renewed hunting on moose in national parks in Poland

Protected areas are the foundation of biodiversity conservation. However, due to their limited size, unfavourable shape, and isolation they often rarely provide sufficient protection. This problem particularly concerns large mammals, which play the role of key-species and usually have high spatial demands. Since 2001 the moose has been under a hunting ban in Poland after the species experienced a sharp decline due to overharvesting. As there are plans to reopen moose hunting in eastern Poland (excluding national parks and nature reserves), we analysed the potential impact of renewed hunting in areas neighbouring Biebrza and Polesie National Parks (eastern Poland) on moose populations inhabiting these protected areas and investigated the suitability of the existing buffer zones to provide additional protection to moose outside the park boundaries. Analyses were based on the tracking data derived from 33 GPS collared moose (24 – Biebrza NP and 9 – Polesie NP). All of the tracked moose utilized areas both inside and outside national parks. In the Biebrza PN, moose spent 46.9% of their time in areas surrounding the national park, whilst in Polesie NP the proportion was 64.5%. The highest utilization of areas outside both study sites occurred in autumn and winter (October–March), a period that considerably overlaps with the planned hunting season. The southern part of Biebrza NP and its official buffer zone covered 96.2% of all moose fixes, while Polesie NP, its official buffer zone and neighbouring landscape park covered 60.3% of moose records. The buffer zones proposed in this paper, whose widths were calculated on the basis of moose tracking data, would protect from 90.5 (Polesie) to 91.2% (Biebrza) of moose fixes. Proper delineation and adequate management plans in buffer zones would prevent the negative impacts of moose hunting, which has the potential to significantly influence ecotourism in national parks and their vicinity.     

In?vitro and in?vivo study on the effect of antifungal agents on hematopoietic cells in mice

Liposomal amphotericin B, voriconazole, and caspofungin are currently used for systemic and severe fungal infections. Patients with malignant diseases are treated with granulocyte-colony stimulating factor (G-CSF) for the recovery of granulocytes after chemotherapy or hematopoietic cell (HC) transplantation. Since they have a high incidence of fungal infections, they inevitably receive antifungal drugs for treatment and prophylaxis. Despite their proven less toxicity for various cell types comparatively with amphotericin B and the decrease in the number of leukocytes that has been reported as a possible complication in clinical studies, the effect of liposomal amphotericin B, voriconazole, and caspofungin on HCs has not been clarified. The present study aimed to examine the in vitro and in vivo effect of these three modern antifungals on HCs. Colony-forming unit (CFU) assays of murine bone marrow cells were performed in methylcellulose medium with or without cytokines and in the presence or absence of various concentrations of liposomal amphotericin B, voriconazole, and caspofungin. In the in vivo experiments, the absolute number of granulocytes was determined during leukocyte recovery in sublethally irradiated mice receiving each antifungal agent separately, with or without G-CSF. In vitro, all three antifungal drugs were nontoxic and, interestingly, they significantly increased the number of CFU-granulocyte-macrophage colonies in the presence of cytokines, at all concentrations tested. This was contrary to the concentration-dependent toxicity and the significant decrease caused by conventional amphotericin B. In vivo, the number of granulocytes was significantly higher with caspofungin plus G-CSF treatment, higher and to a lesser extent higher, but not statistically significantly, with voriconazole plus G-CSF and liposomal amphotericin B plus G-CSF treatments, respectively, as compared with G-CSF alone. These data indicate a potential synergistic effect of these antifungals with the cytokines, in vitro and in vivo, with subsequent positive effect on hematopoiesis.     

Comparison of static and shake culture in the decolorization of textile dyes and dye effluents byPhanerochœte chrysosporium

Decolorization of several dyes (Red HE-8B, Malachite Green, Navy Blue HE-2R, Magenta, Crystal Violet) and an industrial effluent with growing cells ofPhanerochœte chrysosporium in shake and static culture was demonstrated. All the dyes and the industrial effluent were decolorized to some extent with varying percentages of decolorization (20–100%). The rate of decolorization was very rapid with Red HE-8B, an industrial dye. Decolorization rates for all the dyes in static condition were found to be less than the shake culture and also dependent on biomass concentration.