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Applied Microbiology and Biotechnology Jun 2024Direct ammonia oxidation (Dirammox) might be of great significance to advance the innovation of biological nitrogen removal process in wastewater treatment systems....
Direct ammonia oxidation (Dirammox) might be of great significance to advance the innovation of biological nitrogen removal process in wastewater treatment systems. However, it remains unknown whether Dirammox bacteria can be selectively enriched in activated sludge. In this study, a lab-scale bioreactor was established and operated for 2 months to treat synthetic wastewater with hydroxylamine as a selection pressure. Three Dirammox strains (Alcaligenes aquatilis SDU_AA1, Alcaligenes aquatilis SDU_AA2, and Alcaligenes sp. SDU_A2) were isolated from the activated sludge, and their capability to perform Dirammox process was confirmed. Although these three Dirammox bacteria were undetectable in the seed sludge (0%), their relative abundances rapidly increased after a month of operation, reaching 12.65%, 0.69%, and 0.69% for SDU_A2, SDU_AA1, and SDU_AA2, respectively. Among them, the most dominant Dirammox (SDU_A2) exhibited higher nitrogen removal rate (32.35%) than the other two strains (13.57% of SDU_AA1 and 14.52% of SDU_AA2). Comparative genomic analysis demonstrated that the most dominant Dirammox bacterium (SDU_A2) possesses fewer complete metabolic modules compared to the other two less abundant Alcaligenes strains. Our findings expanded the understanding of the application of Dirammox bacteria as key functional microorganisms in a novel biological nitrogen and carbon removal process if they could be well stabilized. KEY POINTS: • Dirammox-dominated microbial community was enriched in activated sludge bioreactor. • The addition of hydroxylamine played a role in Dirammox enrichment. • Three Dirammox bacterial strains, including one novel species, were isolated.
Topics: Wastewater; Bioreactors; Nitrogen; Alcaligenes; Oxidation-Reduction; Sewage; Ammonia; Water Purification; Hydroxylamine; Phylogeny; RNA, Ribosomal, 16S; Bacteria; Microbiota
PubMed: 38904674
DOI: 10.1007/s00253-024-13214-2 -
RSC Advances Jun 2024Interlocked compounds such as rotaxanes and catenanes exhibit unique kinetic properties in response to external chemical or physical stimuli and are therefore expected...
Interlocked compounds such as rotaxanes and catenanes exhibit unique kinetic properties in response to external chemical or physical stimuli and are therefore expected to be applied to molecular machines and molecular sensors. To develop a novel rotaxane for this application, an isophthalamide macrocycle and a neutral phenanthroline axle were used. Stable pseudorotaxanes are known to be formed using hydrogen bonds and π-π interactions. In this study, we designed a non-symmetric axial molecule and synthesized a [2]rotaxane with the aim of introducing two different stations; a phenanthroline and a secondary amine/ammonium unit. Furthermore, H NMR measurements demonstrated that the obtained rotaxane acts as a molecular switch upon application of external acid/base stimuli.
PubMed: 38903675
DOI: 10.1039/d4ra03532a -
Nature Communications Jun 2024Enzymes of the central metabolism tend to assemble into transient supramolecular complexes. However, the functional significance of the interactions, particularly...
Enzymes of the central metabolism tend to assemble into transient supramolecular complexes. However, the functional significance of the interactions, particularly between enzymes catalyzing non-consecutive reactions, remains unclear. Here, by co-localizing two non-consecutive enzymes of the TCA cycle from Bacillus subtilis, malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICD), in phase separated droplets we show that MDH-ICD interaction leads to enzyme agglomeration with a concomitant enhancement of ICD catalytic rate and an apparent sequestration of its reaction product, 2-oxoglutarate. Theory demonstrates that MDH-mediated clustering of ICD molecules explains the observed phenomena. In vivo analyses reveal that MDH overexpression leads to accumulation of 2-oxoglutarate and reduction of fluxes flowing through both the catabolic and anabolic branches of the carbon-nitrogen intersection occupied by 2-oxoglutarate, resulting in impeded ammonium assimilation and reduced biomass production. Our findings suggest that the MDH-ICD interaction is an important coordinator of carbon-nitrogen metabolism.
Topics: Citric Acid Cycle; Nitrogen; Carbon; Malate Dehydrogenase; Bacillus subtilis; Isocitrate Dehydrogenase; Ketoglutaric Acids; Bacterial Proteins; Ammonium Compounds
PubMed: 38902266
DOI: 10.1038/s41467-024-49646-7 -
Scientific Reports Jun 2024Newly synthesized gemini quaternary ammonium salts (QAS) with different counterions (bromide, hydrogen chloride, methylcarbonate, acetate, lactate), chain lengths (C12,...
Newly synthesized gemini quaternary ammonium salts (QAS) with different counterions (bromide, hydrogen chloride, methylcarbonate, acetate, lactate), chain lengths (C12, C14, C16) and methylene linker (3xCH) were tested. Dihydrochlorides and dibromides with 12 carbon atoms in hydrophobic chains were characterized by the highest biological activity against planktonic forms of yeast and yeast-like fungi. The tested gemini surfactants also inhibited the production of filaments by C. albicans. Moreover, they reduced the adhesion of C. albicans cells to the surfaces of stainless steel, silicone and glass, and slightly to polystyrene. In particular, the gemini compounds with 16-carbon alkyl chains were most effective against biofilms. It was also found that the tested surfactants were not cytotoxic to yeast cells. Moreover, dimethylcarbonate (2xCMeCOG) did not cause hemolysis of sheep erythrocytes. Dihydrochlorides, dilactate and diacetate showed no mutagenic potential.
Topics: Biofilms; Quaternary Ammonium Compounds; Antifungal Agents; Candida albicans; Animals; Sheep; Surface-Active Agents; Hemolysis; Erythrocytes; Microbial Sensitivity Tests; Cell Adhesion; Stainless Steel
PubMed: 38898117
DOI: 10.1038/s41598-024-64859-y -
Molecules (Basel, Switzerland) Jun 2024Ammonium polyphosphate (APP), a pivotal constituent within environmentally friendly flame retardants, exhibits notable decomposition susceptibility and potentially...
Ammonium polyphosphate (APP), a pivotal constituent within environmentally friendly flame retardants, exhibits notable decomposition susceptibility and potentially engenders ecological peril. Consequently, monitoring the APP concentration to ensure product integrity and facilitate the efficacious management of wastewater from production processes is of great significance. A fluorescent assay was devised to swiftly discern APP utilizing 4',6'-diamino-2-phenylindole (DAPI). With increasing APP concentrations, DAPI undergoes intercalation within its structure, emitting pronounced fluorescence. Notably, the flame retardant JLS-PNA220-A, predominantly comprising APP, was employed as the test substrate. Establishing a linear relationship between fluorescence intensity (F-F0) and JLS-PNA220-A concentration yielded the equation y = 76.08x + 463.2 (R = 0.9992), with a LOD determined to be 0.853 mg/L. The method was used to assess the degradation capacity of APP-degrading bacteria. Strain D-3 was isolated, and subsequent analysis of its 16S DNA sequence classified it as belonging to the genus. D-3 demonstrated superior APP degradation capabilities under pH 7 at 37 °C, with degradation rates exceeding 85% over a four-day cultivation period. It underscores the sensitivity and efficacy of the proposed method for APP detection. Furthermore, D-3 exhibits promising potential for remediation of residual APP through environmental biodegradation processes.
Topics: Biodegradation, Environmental; Acinetobacter; Polyphosphates; Indoles; Ammonium Compounds; Flame Retardants
PubMed: 38893541
DOI: 10.3390/molecules29112667 -
Molecules (Basel, Switzerland) Jun 2024Recovering valuable active substances from the by-products of agricultural processing is a crucial concern for scientific researchers. This paper focuses on the...
Recovering valuable active substances from the by-products of agricultural processing is a crucial concern for scientific researchers. This paper focuses on the enrichment of soybean trypsin inhibitor (STI) from soybean whey wastewater using either ammonium sulfate salting or ethanol precipitation, and discusses their physicochemical properties. The results show that at a 60% ethanol content, the yield of STI was 3.983 mg/mL, whereas the yield was 3.833 mg/mL at 60% ammonium sulfate saturation. The inhibitory activity of STI obtained by ammonium sulfate salting out (A-STI) was higher than that obtained by ethanol precipitation (E-STI). A-STI exhibited better solubility than E-STI at specific temperatures and pH levels, as confirmed by turbidity and surface hydrophobicity measurements. Thermal characterization revealed that both A-STI and E-STI showed thermal transition temperatures above 90 °C. Scanning electron microscopy demonstrated that A-STI had a smooth surface with fewer pores, while E-STI had a rough surface with more pores. In conclusion, there was no significant difference in the yield of A-STI and E-STI ( < 0.05); however, the physicochemical properties of A-STI were superior to those of E-STI, making it more suitable for further processing and utilization. This study provides a theoretical reference for the enrichment of STI from soybean whey wastewater.
Topics: Glycine max; Wastewater; Whey; Trypsin Inhibitors; Ammonium Sulfate; Chemical Precipitation; Hydrogen-Ion Concentration; Solubility; Hydrophobic and Hydrophilic Interactions; Temperature
PubMed: 38893489
DOI: 10.3390/molecules29112613 -
Nutrients May 2024Studies have suggested that alkalinized foods may reduce the effects of the acidogenic Western diet in promoting obesity, metabolic syndrome, type 2 diabetes, cancer,...
Studies have suggested that alkalinized foods may reduce the effects of the acidogenic Western diet in promoting obesity, metabolic syndrome, type 2 diabetes, cancer, and coronary heart disease. Indeed, a recent study in mice fed a high-fat diet containing dietary beef supplemented with ammonium hydroxide showed improvement in a suite of metabolic outcomes. However, the effects of dietary protein ammonium supplementation on the microbiome remain unknown. In this study, the effects of ammonium supplementation on beef protein towards microbiome taxa and function in a high-fat diet were analyzed. Fecal microbiomes were characterized using a shotgun metagenomic approach for 16-month-old male and female mice after long-term diet treatments. The results for ammoniated diets showed that several bacteria known to be associated with health benefits increased significantly, including , , and . The beneficial mucin-degrader was especially abundant, with a high prevalence (~86%) in females. Concurrently, the phyla Actinomycetota (Actinobacteria) and Bacteroidota (Bacteroidetes) were significantly reduced. While sex was a confounding factor affecting microbiome responses to ammonium supplementation in dietary protein, it is worth noting that several putatively beneficial microbiome functions increased with ammonium supplementation, such as glycine betaine transport, xenobiotic detoxification, enhanced defense, and others. Conversely, many disease-associated microbiome functions reduced. Importantly, modifying protein pH alone via ammonium supplementation induced beneficial microbiota changes. Taken together, these results suggest that ammonium-supplemented proteins may mediate some negative microbiome-associated effects of high-fat/Western diets.
Topics: Animals; Diet, High-Fat; Female; Male; Gastrointestinal Microbiome; Mice; Dietary Supplements; Ammonium Hydroxide; Feces; Red Meat; Dietary Proteins; Bacteria; Cattle
PubMed: 38892546
DOI: 10.3390/nu16111613 -
International Journal of Molecular... May 2024Esterquats constitute a unique group of quaternary ammonium salts (QASs) that contain an ester bond in the structure of the cation. Despite the numerous advantages of... (Review)
Review
Esterquats constitute a unique group of quaternary ammonium salts (QASs) that contain an ester bond in the structure of the cation. Despite the numerous advantages of this class of compounds, only two mini-reviews discuss the subject of esterquats: the first one (2007) briefly summarizes their types, synthesis, and structural elements required for a beneficial environmental profile and only briefly covers their applications whereas the second one only reviews the stability of selected betaine-type esterquats in aqueous solutions. The rationale for writing this review is to critically reevaluate the relevant literature and provide others with a "state-of-the-art" snapshot of choline-type esterquats and betaine-type esterquats. Hence, the first part of this survey thoroughly summarizes the most important scientific reports demonstrating effective synthesis routes leading to the formation of both types of esterquats. In the second section, the susceptibility of esterquats to hydrolysis is explained, and the influence of various factors, such as the pH, the degree of salinity, or the temperature of the solution, was subjected to thorough analysis that includes quantitative components. The next two sections refer to various aspects associated with the ecotoxicity of esterquats. Consequently, their biodegradation and toxic effects on microorganisms are extensively analyzed as crucial factors that can affect their commercialization. Then, the reported applications of esterquats are briefly discussed, including the functionalization of macromolecules, such as cotton fabric as well as their successful utilization on a commercial scale. The last section demonstrates the most essential conclusions and reported drawbacks that allow us to elucidate future recommendations regarding the development of these promising chemicals.
Topics: Betaine; Choline; Cations; Esters; Quaternary Ammonium Compounds; Humans
PubMed: 38891947
DOI: 10.3390/ijms25115761 -
BMC Oral Health Jun 2024One of the most prevalent health problems affecting children worldwide is untreated caries in primary teeth. Agents to arrest caries are used to manage untreated decay... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
One of the most prevalent health problems affecting children worldwide is untreated caries in primary teeth. Agents to arrest caries are used to manage untreated decay in children in disadvantaged communities. Nano Silver Fluoride (NSF) overcomes the staining problems of Silver Diamine Fluoride (SDF). This study compared the clinical cariostatic effect of NSF to 38% SDF for arresting caries lesions.
METHODS
The study included 360 children younger than 4 years, with at least one active lesion, ICDAS score ≥ 3, recruited from nurseries in a rural area in Alexandria, Egypt, in 2022. They were randomly assigned to receive a single application of NSF at baseline, or two applications of SDF at baseline and after 6 months. The arrest of active carious lesions was assessed after 6 and 12 months using ICDAS criteria, and parents' satisfaction with child appearance was also assessed. Chi-Square test was used to compare the groups and multi-level multiple logistic regression was used to assess the effect of the intervention on caries arrest at lesion level and binary logistic regression was used to assess the effect at patient level.
RESULTS
1853 active lesions were included in children whose mean (SD) age was 42.3 (8.2) months. The arrest rate was significantly higher in the NSF than the SDF group at lesion level (78.4% and 65.0% at 6 months and 71.3% and 56.3% at 12 months, p < 0.001). In regression analysis, NSF had significantly higher odds of caries arrest than SDF at lesion level (at 6 months, AOR = 2.57, 95% CI: 1.55, 4.26 and at 12 month, AOR = 3.27, 95% CI: 1.89, 5.67). Parents of children receiving NSF had significantly greater satisfaction with their children's dental appearance than those receiving SDF: (97.2% and 76.1%, respectively, p < 0.001).
CONCLUSION
NSF demonstrated greater effectiveness in arresting caries in preschool children without inducing black staining of teeth and with greater parental satisfaction than SDF. NSF can be an alternative to SDF in arresting caries especially in underprivileged communities.
TRIAL REGISTRATION
The trial was registered in the clinicaltrials.gov registry (#NCT05255913)-16/02/2022.
Topics: Humans; Dental Caries; Silver Compounds; Fluorides, Topical; Quaternary Ammonium Compounds; Child, Preschool; Female; Male; Cariostatic Agents; Fluorides; Infant; Treatment Outcome
PubMed: 38890627
DOI: 10.1186/s12903-024-04406-3 -
BMC Plant Biology Jun 2024Nitrogen (N) availability is crucial in regulating plants' abiotic stress resistance, particularly at the seedling stage. Nevertheless, plant responses to N under...
BACKGROUND
Nitrogen (N) availability is crucial in regulating plants' abiotic stress resistance, particularly at the seedling stage. Nevertheless, plant responses to N under salinity conditions may vary depending on the soil's NH to NO ratio.
METHODS
In this study, we investigated the effects of different NH:NO ratios (100/0, 0/100, 25/75, 50/50, and 75/25) on the growth and physio-biochemical responses of soybean seedlings grown under controlled and saline stress conditions (0-, 50-, and 100-mM L NaCl and NaSO, at a 1:1 molar ratio).
RESULTS
We observed that shoot length, root length, and leaf-stem-root dry weight decreased significantly with increased saline stress levels compared to control. Moreover, there was a significant accumulation of Na, Cl, hydrogen peroxide (HO), and malondialdehyde (MDA) but impaired ascorbate-glutathione pools (AsA-GSH). They also displayed lower photosynthetic pigments (chlorophyll-a and chlorophyll-b), K ion, K/Na ratio, and weakened O-HO-scavenging enzymes such as superoxide dismutase, catalase, peroxidase, monodehydroascorbate reductase, glutathione reductase under both saline stress levels, while reduced ascorbate peroxidase, and dehydroascorbate reductase under 100-mM stress, demonstrating their sensitivity to a saline environment. Moreover, the concentrations of proline, glycine betaine, total phenolic, flavonoids, and abscisic acid increased under both stresses compared to the control. They also exhibited lower indole acetic acid, gibberellic acid, cytokinins, and zeatine riboside, which may account for their reduced biomass. However, NH:NO ratios caused a differential response to alleviate saline stress toxicity. Soybean seedlings supplemented with optimal ratios of NH:NO (T3 = 25:75 and T = 4 50:50) displayed lower Na and Cl and ABA but improved K and K/Na, pigments, growth hormones, and biomass compared to higher NH:NO ratios. They also exhibited higher O-HO-scavenging enzymes and optimized HO, MDA, and AsA-GSH pools status in favor of the higher biomass of seedlings.
CONCLUSIONS
In summary, the NH and NO ratios followed the order of 50:50 > 25:75 > 0:100 > 75:25 > 100:0 for regulating the morpho-physio-biochemical responses in seedlings under SS conditions. Accordingly, we suggest that applying optimal ratios of NH and NO (25/75 and 50:50) can improve the resistance of soybean seedlings grown in saline conditions.
Topics: Glycine max; Seedlings; Antioxidants; Plant Growth Regulators; Salt Tolerance; Nitrates; Ammonium Compounds; Salt Stress; Ions
PubMed: 38890574
DOI: 10.1186/s12870-024-05294-z