Microbiome assembly mechanism and functional potential in enhanced biological phosphorus removal system enriched with Tetrasphaera-related polyphosphate accumulating organisms.

Tetrasphaera-related polyphosphate accumulating organisms (PAOs) are the key functional guilds for enhanced biological phosphorus removal (EBPR) systems. Their biomass enrichment can be enhanced by the nitrification inhibitor allylthiourea (ATU). However, the underlying assembly mechanism and the functional potential of the EBPR microbiome regulated by ATU are unclear. This study investigates the effect of ATU on microbiome assembly and functional potential by closely following the microbiota dynamics in an EBPR system enriched with Tetrasphaera-related PAOs for 288-days before, during and after ATU addition. The results showed that ATU addition increased microbiota structural similarity and compositional convergence, and enhanced determinism in the assembly of EBPR microbiome. During exposure to ATU, Tetrasphaera-related PAOs were governed by homogeneous selection and the dominant species revealed by 16S rRNA gene-based phylogenetic analysis shifted from clade III to clade I. Meanwhile, ATU supply promoted significant enrichment of functional genes involved in phosphate transport (pit) and polyphosphate synthesis and degradation (ppk1 and ppk2), whereas both Nitrosomonas and ammonia monooxygenase-encoding genes (amoA/B/C) assignable to this group of nitrifying bacteria decreased. Moreover, ATU addition relieved the significant abundance correlation between filamentous bacteria Ca. Promineofilum and denitrifying Brevundimonas (FDR-adjusted P < 0.01), damaging their potential synergic or cooperative interactions, thus weakening their competitiveness against Tetrasphaera-related PAOs. Notably, ATU withdrawn created opportunistic conditions for the unexpected explosive growth and predominance of Thiothrix filaments, leading to a serious bulking event. Our study provides new insights into the microbial ecology of Tetrasphaera-related PAOs in EBPR system, which could guide the establishment of an efficient microbiota for EBPR.

Measuring Responses of Dicyandiamide-, 3,4-Dimethylpyrazole Phosphate-, and Allylthiourea-Induced Nitrification Inhibition to Soil Abiotic and Biotic Factors.

Nitrification inhibitors (NIs) such as dicyandiamide (DCD), 3,4-dimethylpyrazole phosphate (DMPP), and allylthiourea (AT) are commonly used to suppress ammonia oxidization at different time scales varying from a few hours to several months. Although the responses of NIs to edaphic and temperature conditions have been studied, the influence of the aforementioned factors on their inhibitory effect remains unknown. In this study, laboratory-scale experiments were conducted to assess the short-term (24 h) influence of eight abiotic and biotic factors on the inhibitory effects of DCD, DMPP, and AT across six cropped and non-cropped soils at two temperature conditions with three covariates of soil texture. Simultaneously, the dominant contributions of ammonia-oxidizing archaea (AOA) and bacteria (AOB) to potential ammonia oxidization (PAO) were distinguished using the specific inhibitor 2 phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO). Our results revealed that AT demonstrated a considerably greater inhibitory effect (up to 94.9% for an application rate of 75 mg of NI/kg of dry soil) than DCD and DMPP. The inhibitory effect of AT was considerably affected by the relative proportions of silt, sand, and clay in the soil and total PAO. In contrast to previous studies, the inhibitory effects of all three NIs remained largely unaffected by the landcover type and temperature conditions for the incubation period of 24 h. Furthermore, the efficacy of all three tested NIs was not affected by the differential contributions of AOA and AOB to PAO. Collectively, our results suggested a limited influence of temperature on the inhibitory effects of all three NIs but a moderate dependence of AT on the soil texture and PAO. Our findings can enhance the estimation of the inhibitory effect in soil, and pure cultures targeting the AOA and AOB supported ammonia oxidization and, hence, nitrogen dynamics under NI applications.

Responses of AOA and AOB activity and DNA/cDNA community structure to allylthiourea exposure in the water level fluctuation zone soil.

Ammonia oxidation is mainly performed by ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Allylthiourea (ATU) has been found to specifically inhibit ammonia oxidation. However, the effect of ATU on AOA and AOB transcription has been infrequently studied. In the present study, we examined the responses of AOA and AOB activity and DNA/cDNA community structure to ATU exposure. The ammonia oxidation activity in the 100-mg/L ATU group was 4.3% of that in the control group after 7 days. When exposed to ATU, the gene abundance of AOA was favored compared with that of AOB, and there were no statistically significant differences in the abundance of AOB amoA in DNA and cDNA between the two groups. Compared with the control group, the gene abundance of AOA significantly increased by 5.23 times, while the transcription of AOA significantly decreased by 0.70 times. Moreover, the transcriptional ratio of AOA in the ATU group was only 0.05 times as high as that in the control group. ATU selectively affected AOB and completely inhibited Nitrosomonas europaea and Bacterium amoA.22.HaldeII.kultur at the genetic level. Under ATU exposure, all AOA clusters were transcribed, but three AOB clusters were not transcribed. Our results indicated that the ammonia oxidation potential of the soil of water level fluctuation areas, based on ATU inhibition, was associated mainly with AOA amoA gene abundance and AOB community shifts in DNA and cDNA.

Anticancer evaluation of N-benzoyl-3-allylthiourea as potential antibreast cancer agent through enhances HER-2 expression.

Breast cancer with HER-2 overexpression is sensitive to drugs which target the receptor or its kinase activity. Although the anti-HER-2 therapies commonly used have improved patient outcome, resistance usually occurs. In this present study, we investigated a modification of the chemical structure of allylthiourea derivatives in order to enhance the cytotoxicity effect on breast cancer cells with HER-2 overexpression. The aim of this research was to predict the absorption, distribution, metabolism, excretion, and toxicity by in silico study and to explore the effect N-benzoyl-3-allylthiourea (BATU) on MCF-7 cell line with overexpressing of HER-2 using MTT assay and western blot. The result showed that the cytotoxicity effects of BATU on MCF-7/HER-2 cell line (IC50 value 0.64 mM) were higher than on MCF-7 cell lines (IC50 value 1.47 mM). In addition, the cytotoxic effects of BATU on MCF-7 and MCF-7/HER-2 were higher than allylthiourea as a lead compound (IC50 value 5.22 and 3.17 mM). The results also confirmed that the BATU compound has the ability to effectively enhance its cytotoxicity against MCF-7/HER-2 through enhanced HER-2 expression and inhibition of nuclear factor kappa B (NF-kB) activation. Above all, the BATU compound is effective in increasing HER-2 expression and inactivating NF-kB transcription factors, thereby resulting in inhibition of protein expression which works a significant part in cell proliferation. Therefore, the BATU compound has the potential to be developed as a complementary drug in breast cancer therapy with HER-2 positive.

Performance of restricted access copper-imprinted poly(allylthiourea) in an on-line preconcentration and sample clean-up FIA-FAAS system for copper determination in milk samples.

A new on-line solid phase preconcentration method using an ion-imprinted polymer with restrict access material based on copper-imprinted poly(allylthiourea) modified with 2-hydroxyethyl methacrylate and bovine serum (IIP-HEMA-BSA) to preconcentrate Cu2+ ions and exclude protein from milk samples via FIA-FAAS was developed. The samples were on-line preconcentrated at pH 4.5 through a mini-column packed with 50.0 mg of IIP-HEMA-BSA at a flow rate of 7.6 mL min-1 followed by a counter-current elution with 1.00 mol L-1 HCl towards the FAAS detector. The interference of ions commonly found in milk samples and the presence of BSA were investigated in the Cu2+ ions preconcentration. The method provided an analytical curve ranging from 3.6 to 100.0 µg L-1, preconcentration factor of 24-fold, limit of detection of 1.1 µg L-1 and sample throughput of 20 h-1. The accuracy of the method was attested by Cu2+ ions addition/recovery tests as well as by using GFAAS of samples microwave-assisted digested. The proposed method was successfully applied to the copper determination in milk samples, requiring only pH adjustment followed by preconcentration step as sample pretreatment. Copper content in bovine milk sample was 0.635 ±â€¯0.042 mg kg-1, while to soybean milk samples were between 0.048 ±â€¯0.008 and 0.094 ±â€¯0.005 mg kg-1. To the best of our knowledge, the potential of IIP-HEMA-BSA for Cu2+ ions extraction from biological samples and simultaneous removal of macromolecules employing minimal sample pretreatment was demonstrated for the first time. The proposed extraction method stands out by being simple, fast and a low-cost analytical strategy when compared to the conventional microwave-assisted acid digestion.

Preparation of Poly (Allylthiourea-Co-Acrylic Acid) Derived Carbon Materials and Their Applications in Wastewater Treatment.

Functional carbon materials have been developed and applied in various sewage treatment applications in recent years. This article reports the fabrication, characterization, and application of a new kind of poly (allylthiourea-co-acrylic acid) (PAT⁻PAC) hydrogel-based carbon monolith. The results indicated that the poly acrylic acid component can endow the PAT⁻PAC hydrogel with an increased swelling ratio and enhanced thermal stability. During the carbonization process, O⁻H, N⁻H, C=N, and ⁻COO⁻ groups, etc. were found to be partly decomposed, leading to the conjugated C=C double bonds produced and the clear red shift of C=O bonds. Particularly, it was found that this shift was accelerated under higher carbonization temperature, which ultimately resulted in the complex conjugated C=C network with oxygen, nitrogen, and sulfur atoms doped in-situ. The as-obtained carbon monoliths showed good removal capacity for Ni(II) ions, organic solvents, and dyes, respectively. Further analysis indicated that the Ni(II) ion adsorption process could be well described by pseudo-second-order and Freundlich models under our experimental conditions, respectively. The adsorption capacity for Ni(II) ions and paraffin oil was as high as 557 mg/g and 1.75 g/g, respectively. More importantly, the as-obtained carbon monoliths can be recycled and reused for Ni(II) ions, acetone, and paraffin oil removal. In conclusion, the proposed PAT⁻PAC-based carbonaceous monoliths are superior adsorbents for wastewater treatment.

Relative contribution of ammonia oxidizing bacteria and other members of nitrifying activated sludge communities to micropollutant biotransformation.

Improved micropollutant (MP) biotransformation during biological wastewater treatment has been associated with high ammonia oxidation activities, suggesting co-metabolic biotransformation by ammonia oxidizing bacteria as an underlying mechanism. The goal of this study was to clarify the contribution of ammonia oxidizing bacteria to increased MP degradation in nitrifying activated sludge (NAS) communities using a series of inhibition experiments. To this end, we treated a NAS community with two different ammonia oxidation inhibitors, namely octyne (OCT), a mechanistic inhibitor that covalently binds to ammonia monooxygenases, and allylthiourea (ATU), a copper chelator that depletes copper ions from the active center of ammonia monooxygenases. We investigated the biotransformation of 79 structurally different MPs by the inhibitor-treated and untreated sludge communities. Fifty-five compounds exhibited over 20% removal in the untreated control after a 46 h-incubation. Of these, 31 compounds were significantly inhibited by either ATU and/or OCT. For 17 of the 31 MPs, the inhibition by ATU at 46 h was substantially higher than by OCT despite the full inhibition of ammonia oxidation by both inhibitors. This was particularly the case for almost all thioether and phenylurea compounds tested, suggesting that in nitrifying activated sludge communities, ATU does not exclusively act as an inhibitor of bacterial ammonia oxidation. Rather, ATU also inhibited enzymes contributing to MP biotransformation but not to bulk ammonia oxidation. Thus, inhibition studies with ATU tend to overestimate the contribution of ammonia-oxidizing bacteria to MP biotransformation in nitrifying activated sludge communities. Biolog tests revealed only minor effects of ATU on the heterotrophic respiration of common organic substrates by the sludge community, suggesting that ATU did not affect enzymes that were essential in energy conservation and central metabolism of heterotrophs. By comparing ATU- and OCT-treated samples, as well as before and after ammonia oxidation was recovered in OCT-treated samples, we were able to demonstrate that ammonia-oxidizing bacteria were highly involved in the biotransformation of four compounds: asulam, clomazone, monuron and trimethoprim.

Ammonia-limited conditions cause of Thaumarchaeal dominance in volcanic grassland soil.

The first step of nitrification is carried out by ammonia-oxidizing bacteria (AOB) and archaea (AOA). It is largely unknown, by which mechanisms these microbes are capable of coexistence and how their respective contribution to ammonia oxidation may differ with varying soil characteristics. To determine how different levels of ammonium availability influence the extent of archaeal and bacterial contributions to ammonia oxidation, microcosm incubations with controlled ammonium levels were conducted. Net nitrification was monitored and ammonia-oxidizer communities were quantified. Additionally, the nitrification inhibitor allylthiourea (ATU) was applied to discriminate between archaeal and bacterial contributions to soil ammonia oxidation. Thaumarchaeota, which were the only ammonia oxidizers detectable at the start of the incubation, grew in all microcosms, but AOB later became detectable in ammonium amended microcosms. Low and high additions of ammonium increasingly stimulated AOB growth, while AOA were only stimulated by the low addition. Treatment with ATU had no effect on net nitrification and sizes of ammonia-oxidizing communities suggesting that the effective concentration of ATU to discriminate between archaeal and bacterial ammonia oxidation is not the same in different soils. Our results support the niche-differentiating potential of ammonium concentration for AOA and AOB, and we conclude that ammonium limitation can be a major reason for absence of detectable AOB in soil.

Molecularly imprinted polymer dedicated to the extraction of glyphosate in natural waters.

Three molecularly imprinted polymers (MIPs) have been synthesized in order to bind efficiently glyphosate (GLY) in natural waters (mineral and underground). Since the target analyte is polar and hydrophilic, electrostatic interactions and hydrogen bonds have been favored with two templates (phenylphosphonic acid and diethyl(α-aminobenzyl)-phosphonic acid) and two functional monomers (1-allyl-2-thiourea and methacrylic acid). MIPs have been assessed by comparison of the recoveries obtained with MIP and NIP (non imprinted polymer) by solid-phase extraction (SPE). The selectivity of MIP versus NIP was satisfactory for the three imprinted polymers with a very straightforward protocol: conditioning of 250 mg of MIP or NIP packed in 3-mL polypropylene cartridges with 3 mL Milli-Q water, loading of Milli-Q water (15 mL) spiked with 5 mg L(-1) of GLY and its metabolite, aminomethylphosphonic acid (AMPA) and elution by 3 mL NH4OH (10mM) or 3 mL HCl (100mM). SPE fractions were directly analyzed by capillary electrophoresis (CE). Thus, the recoveries of both analytes were greater than 80% for all MIPs and less than 25% for most NIPs. Moreover, the MIP prepared with 1-allyl-2-thiourea as functional monomer and phenylphosphonic acid as template displayed a capacity of 0.033 µmol/mg for GLY. However, the substitution of Milli-Q water by mineral water caused the decrease of MIP recoveries, for that, a pretreatment of the sample by ionic exchange resins was set up and succeeded in improving recoveries (about 50% for GLY and 25% for AMPA). Then, groundwaters were spiked with low concentrations of GLY and AMPA (0.5 µgL(-1)) and directly percolated through MIP cartridges. The extractions were carried out by triplicate and the elution fractions were analyzed by UPLC-MS/MS. The results showed no retention of AMPA but a total retention of GLY by MIP.

Nitrification performance in a membrane bioreactor treating industrial wastewater.

The influence of industrial (pharmaceutical and chemical) wastewater composition on membrane bioreactor (MBR) performance was investigated in a pilot-scale installation. The study focussed on nitrification performance, which was evaluated based on influent and effluent parameters as well as batch nitrification rate tests. The industrial wastewater was pumped into the MBR in a mixture with municipal wastewater at constant flow rate. The loading of the MBR with industrial wastewater was increased stepwise from 0 to 75% share in the mixed influent to study the adaptation of nitrifying bacteria. Stable nitrification performance was observed until the content of industrial wastewater in the influent reached 40%, with effluent values of around 0.56 mg L(-1) NH4-N and 98.3% ammonia removal. Breakdown of nitratation was observed at a 40% industrial wastewater dose and breakdown of nitritation at a 50% dose, respectively. However, after several months of adaptation, both processes recovered. No nitrification was observed when the industrial wastewater share exceeded 50%. Adaptation of nitrifying bacteria in the MBR was also confirmed by results of kinetic tests. The inhibition effect of the concentrated industrial wastewater to the MBR sludge decreased substantially after several months of exposure, while the inhibition of referential activated sludge remained constant.