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Applied Microbiology and Biotechnology Jun 2024Non-symbiotic N-fixation would greatly increase the versatility of N-biofertilizers for sustainable agriculture. Genetic modification of diazotrophic bacteria has...
Non-symbiotic N-fixation would greatly increase the versatility of N-biofertilizers for sustainable agriculture. Genetic modification of diazotrophic bacteria has successfully enhanced NH release. In this study, we compared the competitive fitness of A. vinelandii mutant strains, which allowed us to analyze the burden of NH release under a broad dynamic range. Long-term competition assays under regular culture conditions confirmed a large burden for NH release, exclusion by the wt strain, phenotypic instability, and loss of the ability to release NH. In contrast, co-inoculation in mild autoclaved soil showed a much longer co-existence with the wt strain and a stable NH release phenotype. All genetically modified strains increased the N content and changed its chemical speciation in the soil. This study contributes one step forward towards bridging a knowledge gap between molecular biology laboratory research and the incorporation of N from the air into the soil in a molecular species suitable for plant nutrition, a crucial requirement for developing improved bacterial inoculants for economic and environmentally sustainable agriculture. KEY POINTS: • Genetic engineering for NH excretion imposes a fitness burden on the culture medium • Large phenotypic instability for NH-excreting bacteria in culture medium • Lower fitness burden and phenotypic instability for NH-excreting bacteria in soil.
Topics: Soil Microbiology; Azotobacter vinelandii; Ammonium Compounds; Nitrogen Fixation; Nitrogen; Genetic Fitness; Phenotype; Soil; Culture Media; Genetic Engineering
PubMed: 38888816
DOI: 10.1007/s00253-024-13231-1 -
BMC Oral Health Jun 2024The black staining effect of silver-containing solutions for use to arrest caries can have a negative aesthetic impact on children and parents. This study aims to assess...
BACKGROUND
The black staining effect of silver-containing solutions for use to arrest caries can have a negative aesthetic impact on children and parents. This study aims to assess the staining effects of Silver Diamine Fluoride/Potassium Iodide (SDF/KI), SDF and Nanosilver Fluoride (NSF).
MATERIALS AND METHODS
Forty-four extracted carious primary molars were collected and randomly divided into four groups (n = 11). The carious tissue in all teeth was removed using a chemo-mechanical caries removal agent with an excavator. After caries removal in all groups, SDF, SDF/KI, and NSF were applied to the different groups, while no solution was applied to the control group. Subsequently, the teeth in all groups were restored with compomer. Color values L*, a* and b* were measured using a spectrophotometer at three time points: immediately after compomer restoration (T), one week later (T), and four week later (T). Changes in brightness (ΔL) and color (ΔE) over time were calculated and comparisons among groups were made.
RESULTS
The SDF solution induced statistically significant black staining (p = 0.013) and a decrease in L* value (p < 0.001) on the compomer material compared to the other groups over time.
CONCLUSIONS
It was observed that SDF/KI has the potential to reduce the black staining effect of SDF, though not entirely. Novel experimental solutions like NSF may offer an alternative to counteract the staining effect of SDF.
Topics: Silver Compounds; Quaternary Ammonium Compounds; Potassium Iodide; Humans; Fluorides, Topical; In Vitro Techniques; Cariostatic Agents; Dental Caries; Tooth Discoloration; Tooth, Deciduous; Spectrophotometry; Molar
PubMed: 38880907
DOI: 10.1186/s12903-024-04370-y -
Scientific Reports Jun 2024Gemini-type imidazoline quaternary ammonium salt is a new type of environmentally friendly corrosion inhibitor has been widely used in engineering materials. However,...
Gemini-type imidazoline quaternary ammonium salt is a new type of environmentally friendly corrosion inhibitor has been widely used in engineering materials. However, most of them are hazardous/toxic compounds derived from petroleum-based products, which did harm to environment. In this work, an environmentally friendly Gemini-shaped imidazoline quaternary ammonium salt corrosion inhibitor (G211) was synthesized using cheap fatty acid recycled from dimer acid industry as feedstock. The corrosion inhibition effects of G211 on Q235 steel in 1 M HCl solution were investigated through weight loss experiments, potential polarization curves, and alternating current impedance spectroscopy experiments. The results show that the inhibition rate of G211 as a mixed-type inhibitor is up to 94.4% and the concentration drop as low as 500 ppm at 25 ℃. The adsorption of G211 on Q235 surface follows Langmuir adsorption isothermal curve. The chemical composition of the Q235 steel surface was analyzed through scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Furthermore, the possible corrosion inhibition mechanism of G211 on the surface of Q235 steel is proposed. This article not only presents an outstanding solution for safeguarding Q235 steel against corrosion but also introduces a feasible method for high-value utilization of monomer acid (MA).
PubMed: 38879631
DOI: 10.1038/s41598-024-64671-8 -
Environment International Jul 2024The linkage between biocides and antibiotic resistance has been widely suggested in laboratories and various environments. However, the action mechanism of biocides on...
The linkage between biocides and antibiotic resistance has been widely suggested in laboratories and various environments. However, the action mechanism of biocides on antibiotic resistance genes (ARGs) spread is still unclear. Thus, 6 quaternary ammonium biocides (QACs) with different bonded substituents or alkyl chain lengths were selected to assess their effects on the conjugation transfer of ARGs in this study. Two conjugation models with the same donor (E. coli DH5α (RP4)) into two receptors, E. coli MG1655 and pathogenic S. sonnei SE6-1, were constructed. All QACs were found to significantly promote intra- and inter-genus conjugative transfer of ARGs, and the frequency was highly impacted by their structure and receptors. At the same environmental exposure level (4 × 10 mg/L), didecyl dimethyl ammonium chloride (DDAC (C10)) promoted the most frequency of conjugative transfer, while benzathine chloride (BEC) promoted the least. With the same donor, the enhanced frequency of QACs of intra-transfer is higher than inter-transfer. Then, the acquisition mechanisms of two receptors were further determined using biochemical combined with transcriptome analysis. For the recipient E. coli, the promotion of the intragenus conjugative transfer may be associated with increased cell membrane permeability, reactive oxygen species (ROS) production and proton motive force (PMF)-induced enhancement of flagellar motility. Whereas, the increase of cell membrane permeability and decreased flagellar motility due to PMF disruption but encouraged biofilm formation, maybe the main reasons for promoting intergenus conjugative transfer in the recipient S. sonnei. As one pathogenic bacterium, S. sonnei was first found to acquire ARGs by biocide exposure.
Topics: Disinfectants; Quaternary Ammonium Compounds; Escherichia coli; Conjugation, Genetic; Drug Resistance, Bacterial; Anti-Bacterial Agents; Drug Resistance, Microbial; Gene Transfer, Horizontal
PubMed: 38878503
DOI: 10.1016/j.envint.2024.108812 -
Ecotoxicology and Environmental Safety Jul 2024Simultaneous heterotrophic nitrification and aerobic denitrification (SND) is gaining tremendous attention due to its high efficiency and low cost in water treatment....
Simultaneous heterotrophic nitrification and aerobic denitrification (SND) is gaining tremendous attention due to its high efficiency and low cost in water treatment. However, SND on an industrial scale is still immature since effects of coexisting pollutants, for example, heavy metals, on nitrogen removal remains largely unresolved. In this study, a HNAD bacterium (Pseudomonas sp. XF-4) was isolated. It could almost completely remove ammonium and nitrate at pH 5-9 and temperature 20 ℃-35 ℃ within 10 h, and also showed excellently simultaneous nitrification and denitrification efficiency under the coexistence of any two of inorganic nitrogen sources with no intermediate accumulation. XF-4 could rapidly grow again after ammonium vanish when nitrite or nitrate existed. There was no significant effects on nitrification and denitrification when Cd(II) was lower than 10 mg/L, and 95 % of Cd(II) was removed by XF-4. However, electron carrier and electron transport system activity was inhibited, especially at high concentration of Cd(II). Overall, this study reported a novel strain capable of simultaneous nitrification and denitrification coupled with Cd(II) removal efficiently. The results provided new insights into treatment of groundwater or wastewater contaminated by heavy metals and nitrogen.
Topics: Cadmium; Denitrification; Nitrification; Pseudomonas; Water Pollutants, Chemical; Nitrogen; Heterotrophic Processes; Nitrates; Wastewater; Biodegradation, Environmental; Aerobiosis; Water Purification; Ammonium Compounds
PubMed: 38878332
DOI: 10.1016/j.ecoenv.2024.116588 -
Ecotoxicology and Environmental Safety Jul 2024Screening and prioritizing research on frequently detected mixture systems in the environment is of great significance, as conducting toxicity testing on all mixtures is...
Screening and prioritizing research on frequently detected mixture systems in the environment is of great significance, as conducting toxicity testing on all mixtures is impractical. Therefore, the frequent itemset mining (FIM) was introduced and applied in this paper to identify variables that commonly co-occur in a dataset. Based on the dataset of the quaternary ammonium compounds (QACs) in the water environment, the four frequent QAC mixture systems with detection rate ≥ 35 % were found, including [BDMM]Cl-[BTMM]Cl (M1), [BDMM]Cl-[BHMM]Cl (M2), [BTMM]Cl -[BHMM]Cl (M3), and [BDMM]Cl-[BTMM]Cl-[BHMM]Cl (M4). [BDMM]Cl, [BTMM]Cl, and [BHMM]Cl are benzyl dodecyl dimethyl ammonium chloride, benzyl tetradecyl dimethyl ammonium chloride, and benzyl hexadecyl dimethyl ammonium chloride, respectively. Then, the toxicity of the representative mixture rays and components for the four frequently detected mixture systems was tested using Vibrio qinghaiensis sp.-Q67 (Q67) as a luminescent indicator organism at 0.25 and 12 h. The toxicity of the mixtures was predicted using concentration addition (CA) and independent action (IA) models. It was shown that both the components and the representative mixture rays for the four frequently detected mixture systems exhibited obvious acute and chronic toxicity to Q67, and their median effective concentrations (EC) were below 7 mg/L. Both CA and IA models predicted the toxicity of the four mixture systems well. However, the CA model had a better predictive ability for the toxicity of the M3 and M4 mixtures than IA at 12 h.
Topics: Quaternary Ammonium Compounds; Water Pollutants, Chemical; Environmental Monitoring; Toxicity Tests; Data Mining
PubMed: 38875820
DOI: 10.1016/j.ecoenv.2024.116581 -
BMC Oral Health Jun 2024Using Silver Diamine Fluoride (SDF) may be an effective public health approach for managing dental caries in children. Parental acceptance of SDF has rarely been...
BACKGROUND
Using Silver Diamine Fluoride (SDF) may be an effective public health approach for managing dental caries in children. Parental acceptance of SDF has rarely been investigated in low-income and middle-income countries (LMICs). The aim of this study was to evaluate parental acceptance of SDF to manage dental caries in children aged 2-12 in Iran and Tajikistan.
METHODS
This cross-sectional study was conducted in the Kurdistan province of Iran and Khatlon region of Tajikistan, 2022-2023. Parents watched a video about SDF and its weaknesses and strengths as compared to conventional approaches before completing the questionnaire. We also reported Prevalence Ratios with 95% confidence intervals for the relationship between parental acceptance and associated demographic factors as well as dental attitude and experience.
RESULTS
Participants were 245 and 160 parents in Iran and Tajikistan, respectively. In both countries, a majority (Iran: 61.6%, Tajikistan: 77.9%) accepted SDF over conventional treatments for all primary teeth. The majority also accepted SDF only for posterior permanent teeth (Iran: 73.5%, Tajikistan: 78.7%). Black discoloration was the main reason for rejecting SDF. Overall, demographic factors and dental experience and attitude were not significantly associated with SDF acceptance.
CONCLUSIONS
SDF was widely accepted by Iranian and Tajik parents. Establishing parental acceptance of SDF is an important step toward its application in LMICs where inexpensive solutions are needed.
Topics: Humans; Cross-Sectional Studies; Fluorides, Topical; Child; Parents; Female; Male; Iran; Silver Compounds; Tajikistan; Child, Preschool; Quaternary Ammonium Compounds; Cariostatic Agents; Dental Caries; Adult; Surveys and Questionnaires; Patient Acceptance of Health Care
PubMed: 38872123
DOI: 10.1186/s12903-024-04434-z -
Nanomaterials (Basel, Switzerland) May 2024Titanium silicon molecular zeolite (TS-1) plays an important role in catalytic reactions due to its unique nanostructure. The straight channel on TS-1 was parallel to...
Titanium silicon molecular zeolite (TS-1) plays an important role in catalytic reactions due to its unique nanostructure. The straight channel on TS-1 was parallel to the orientation of the short b-axis and directly exposed to the aperture of the 10-member ring with a diameter of 0.54 nm × 0.56 nm. This structure could effectively reduce the diffuse restriction of bulk organic compounds during the oxidative desulfurization process. As a kind of cationic polymer electrolyte, polydimethyldiallyl ammonium chloride (PDDA) contains continuous [CHNCl] chain segments, in which the Cl could function as an effective structure-directing agent in the synthesis of nanomaterials. The chain of PDDA could adequately interact with the [0 1 0] plane in the preparation process of zeolite, and then the TS-1 nanosheet with short b-axis thickness (6 nm) could be obtained. The pore structure of the TS-1 nanosheet is controlled by regulating the content of PDDA. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N physical adsorption analysis, infrared absorption spectrum and ultraviolet-visible spectrum were used to determine the TS-1. The thinner nanosheets exhibit excellent catalytic performance in oxidative desulfurization of dibenzothiophene (DBT), in which the removal rate could remain at 100% after three recycles. Here, the TS-1 nanosheet with short b-axis thickness has a promising future in catalytic reactions.
PubMed: 38869578
DOI: 10.3390/nano14110953 -
Journal of Hazardous Materials Aug 2024Progress in the development of biodegradable or biobased ionic liquids (ILs) has led to the design of green compounds for several applications. Herein, four...
Progress in the development of biodegradable or biobased ionic liquids (ILs) has led to the design of green compounds for several applications. Herein, four biocompatible dicationic ionic liquids (DILs) with ammonium-phosphonium cations and amino acid anions were synthesized and investigated their environmental impact. The structures of the DILs were confirmed by spectral analyses (H, C and P NMR). Furthermore, physicochemical properties such as density, viscosity and refractive index were determined. Water content, bromide content and solubility were thereafter determined as the parameters needed for further studies. Subsequently, their antifeedant activity towards economically important pests of grain in storage warehouses: the granary weevil, the confused flour beetle, and the khapra beetle was examined, showing the dependence on structure. Moreover, selected DILs were investigated for toxicity towards white mustard, Daphnia magna, and Artemia franciscana to specify the environmental impact. These studies were complemented by understand the biodegradation of DILs by bacterial communities derived from soil at the agricultural land. The result was DILs with limited environmental footprints that have great potential for further application studies.
Topics: Ionic Liquids; Animals; Amino Acids; Daphnia; Artemia; Ammonium Compounds; Organophosphorus Compounds; Cations; Anions; Environment; Biodegradation, Environmental; Coleoptera
PubMed: 38850954
DOI: 10.1016/j.jhazmat.2024.134793 -
Science Advances Jun 2024Heterotrophic nitrifiers continue to be a hiatus in our understanding of the nitrogen cycle. Despite their discovery over 50 years ago, the physiology and environmental...
Heterotrophic nitrifiers continue to be a hiatus in our understanding of the nitrogen cycle. Despite their discovery over 50 years ago, the physiology and environmental role of this enigmatic group remain elusive. The current theory is that heterotrophic nitrifiers are capable of converting ammonia to hydroxylamine, nitrite, nitric oxide, nitrous oxide, and dinitrogen gas via the subsequent actions of nitrification and denitrification. In addition, it was recently suggested that dinitrogen gas may be formed directly from ammonium. Here, we combine complementary high-resolution gas profiles, N isotope labeling studies, and transcriptomics data to show that hydroxylamine is the major product of nitrification in . We demonstrated that denitrification and direct ammonium oxidation to dinitrogen gas did not occur under the conditions tested. Our results indicate that is capable of hydroxylamine production from an organic intermediate. These results fundamentally change our understanding of heterotrophic nitrification and have important implications for its biotechnological application.
Topics: Alcaligenes faecalis; Nitrification; Hydroxylamine; Heterotrophic Processes; Ammonium Compounds; Nitrites; Oxidation-Reduction
PubMed: 38848370
DOI: 10.1126/sciadv.adl3587