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Scientific Reports Jun 2024We previously reported that asthma prevalence was higher in the United States (US) compared to Mexico (MX) (25.8% vs. 8.4%). This investigation assessed differences in...
We previously reported that asthma prevalence was higher in the United States (US) compared to Mexico (MX) (25.8% vs. 8.4%). This investigation assessed differences in microbial dust composition in relation to demographic and housing characteristics on both sides of the US-MX Border. Forty homes were recruited in the US and MX. Home visits collected floor dust and documented occupants' demographics, asthma prevalence, housing structure, and use characteristics. US households were more likely to have inhabitants who reported asthma when compared with MX households (30% vs. 5%) and had significantly different flooring types. The percentage of households on paved roads, with flushing toilets, with piped water and with air conditioning was higher in the US, while dust load was higher in MX. Significant differences exist between countries in the microbial composition of the floor dust. Dust from Mexican homes was enriched with Alishewanella, Paracoccus, Rheinheimera genera and Intrasporangiaceae family. A predictive metagenomics analysis identified 68 significantly differentially abundant functional pathways between US and MX. This study documented multiple structural, environmental, and demographic differences between homes in the US and MX that may contribute to significantly different microbial composition of dust observed in these two countries.
Topics: Dust; Arizona; Humans; Mexico; Housing; Asthma; Bacteria; Female; Family Characteristics; Male; Metagenomics
PubMed: 38834753
DOI: 10.1038/s41598-024-63356-6 -
Toxics Aug 2023Nitrification inhibitors are recognized as a key approach that decreases the denitrification process to inhibit the loss of nitrogen to the atmosphere in the form of NO....
Nitrification inhibitors are recognized as a key approach that decreases the denitrification process to inhibit the loss of nitrogen to the atmosphere in the form of NO. Targeting denitrification microbes directly could be one of the mitigation approaches. However, minimal attempts have been devoted towards the development of denitrification inhibitors. In this study, we aimed to investigate the molecular docking behavior of the nitrous oxide reductase (NOR) and nitrite reductase (NIR) involved in the microbial denitrification pathway. Specifically, in silico screening was performed to detect the inhibitors of nitrous oxide reductase (NOR) and nitrite reductase (NIR) using the PatchDock tool. Additionally, a toxicity analysis based on insecticide-likeness, Bee-Tox screening, and a STITCH analysis were performed using the SwissADME, Bee-Tox, and pkCSM free online servers, respectively. Among the twenty-two compounds tested, nine ligands were predicted to comply well with the TICE rule. Furthermore, the Bee-Tox screening revealed that none of the selected 22 ligands exhibited toxicity on honey bees. The STITCH analysis showed that two ligands, namely procyanidin B2 and thiocyanate, have interactions with both the and microbial proteins. The molecular docking results indicated that ammonia exhibited the second least atomic contact energy (ACE) of -15.83 kcal/mol with nitrous oxide reductase (NOR) and an ACE of -15.20 kcal/mol with nitrite reductase (NIR). The inhibition of both the target enzymes (NOR and NIR) supports the view of a low denitrification property and suggests the potential future applications of natural/synthetic compounds as significant nitrification inhibitors.
PubMed: 37624165
DOI: 10.3390/toxics11080660 -
Water Science and Technology : a... Dec 2023To investigate energy-saving approaches in wastewater treatment plants and decrease aeration energy consumption, this study successfully established a floc-granule...
To investigate energy-saving approaches in wastewater treatment plants and decrease aeration energy consumption, this study successfully established a floc-granule coexistence system in a sequencing batch airlift reactor (SBAR) employing micro-bubble aeration. The analysis focused on granule formation and pollutant removal under various aeration intensities, and compared its performance with a traditional floc-based coarse-bubble aeration system. The results showed that granulation efficiency was positively associated with aeration intensity, which enhanced the secretion of extracellular polymeric substances (EPSs) and facilitated granule formation. The SBAR with the micro-aeration intensity of 30 mL·min showed the best granulation performance (granulation efficiency 52.6%). In contrast to the floc-based system, the floc-granule coexistence system showed better treatment performance, and the best removal efficiencies of NH-N, TN, and TP were 100.0, 77.0, and 89.5%, respectively. The floc-granule coexistence system also enriched higher abundance of nutrients removal microbial species, such as Nitrosomonas (0.05-0.14%), Nitrospira (0.14-2.32%), Azoarcus (2.95-12.17%), Thauera (0.43-1.95%), and Paracoccus (0.76-2.89%). The energy-saving potential was evaluated, which indicated it is feasible for the micro-aeration floc-granule coexistence system to decrease the aeration consumption by 14.4% as well as improve the effluent.
Topics: Sewage; Waste Disposal, Fluid; Bioreactors; Bacteria; Aerobiosis; Nitrogen
PubMed: 38096087
DOI: 10.2166/wst.2023.376 -
The Science of the Total Environment Jan 2024The abundant Fe (hydr-) oxides present in wetland sediments can form stable iron (Fe)-organic carbon (OC) complexes (Fe-OC), which are key mechanisms contributing to the...
The abundant Fe (hydr-) oxides present in wetland sediments can form stable iron (Fe)-organic carbon (OC) complexes (Fe-OC), which are key mechanisms contributing to the stability of sedimentary OC stocks in coastal wetland ecosystems. However, the effects of increased flooding and salinity stress, resulting from global change, on the Fe-OC complexes in sediments remain unclear. In this study, we conducted controlled experiments in a climate chamber to quantify the impacts of flooding and salinity on the different forms of Fe (hydr-) oxides binding to OC in the rhizosphere sediments of S. mariqueter as well as the influence on Fe redox cycling bacteria in the rhizosphere. The results of this study demonstrated that prolonged flooding and high salinity treatments significantly reduced the content of organo-metal complexes (Fe) in the rhizosphere. Under high salinity conditions, the content of Fe-OC increased significantly, while flooding led to a decrease in Fe-OC content, inhibiting co-precipitation processes. The association of amorphous Fe (hydr-) oxides (Fe) with OC showed no significant differences under different flooding and salinity treatments. Prolonged flooding significantly increased the relative abundance of Fe-reducing bacteria (FeRB) Deferrisoma and Geothermobacter and decreased polyphenol oxidase in the rhizosphere, while the relative abundance of Fe-oxidizing bacteria (FeOB) Paracoccus and Pseudomonas decreased with increasing salinity and duration of flooding. Overall, short-term water and salinity stress promoted the binding of Fe to OC in the rhizosphere of S. mariqueter, leading to a reduction in the OC content held by Fe. However, there were no significant differences observed in the OC stocks or the total Fe-OC content in the rhizosphere sediments. The findings suggest a degree of consistency in the Fe-OC of the "plant-soil" complex system within tidal flat wetlands, showing resilience to abrupt shifts in flooding and salinity over short periods.
Topics: Oxides; Ecosystem; Rhizosphere; Carbon; Salinity; Iron; Wetlands; Soil
PubMed: 37956840
DOI: 10.1016/j.scitotenv.2023.168447 -
Heliyon Jan 2024The cotton mealybug, Tinsley and papaya mealybug, Williams and Granara de Willink (Hemiptera: Pseudococcidae) are becoming major threats to the production of R. Br....
The cotton mealybug, Tinsley and papaya mealybug, Williams and Granara de Willink (Hemiptera: Pseudococcidae) are becoming major threats to the production of R. Br. (Asclepiadaceae) in India. Management mainly depends on chemical insecticides which cause a serious problem of pesticide residue and insecticide resistance. The use of biorational insecticides such as biopesticides, botanicals, insect growth regulators, and microbial insecticides is important components of an Integrated Pest Management (IPM) program for successful management. We evaluated the bio-efficacy of twelve biorational insecticides, including entomopathogenic fungi (EPF), using the leaf spray method in laboratory conditions at 25 ± 1 °C, 70 % ± 5 % RH. The results revealed that the highest percent mortality was recorded by acetamiprid 20 % SP (100.00 %), followed by azadirachtin (98.27 %), (2 × 10 spores/mL) (85.70 %) and leaf extract (76.87 %) at 120 h after treatment (HAT) in . In , 100.00 %, 96.39 % and 85.67 % and 74.90 % mortalities were achieved by acetamiprid 20 % SP, azadirachtin, (2 × 10 spores/mL) and leaf extract, respectively, at 120 HAT during the first spray. Various biorational insecticides showed a more or less similar trend of percent mortality in both species during the second spray. In both species, the lowest percent mortality was recorded by leaf extract (46.29, 44.54) and (41.03, 46.39) at 120 Hours after treatment in the first and second spray, respectively. It was concluded that all the prescribed treatments are more effective than the control. Overall, azadirachtin recorded the highest percent mortality after acetamiprid and had the shortest LT (12.52 h) and (13.87 h) values in and , respectively. Our study emphasizes that biopesticides like Azadirachtin 1 % EC (10000 ppm), (2 × 10 spores/mL) (5 mL/L) and leaf extract (5 %) may be recommended as alternatives to synthetic insecticides. Botanicals and EPF would be the most effective approach for sustainable integrated management of and in the ecosystem.
PubMed: 38187271
DOI: 10.1016/j.heliyon.2023.e23648 -
Environmental Research Feb 2024Aerobic granular sludge (AGS) needs a long start-up time and always shows unstable performance when it is used to treat low-strength wastewater. In this study, a rapid...
Aerobic granular sludge (AGS) needs a long start-up time and always shows unstable performance when it is used to treat low-strength wastewater. In this study, a rapid static feeding combined with Fe addition as a novel strategy was employed to improve the formation and stability of AGS in treating low-strength wastewater. Fe-AGS was formed within only 7 days and showed favorable pollutant removal capability and settling performance. The ammonia nitrogen (NH-N) and chemical oxygen demand (COD) concentration in the effluent were lower than 5 mg/L and 50 mg/L after day 23, respectively. The sludge volume index (SVI) and mixed liquid suspended solids (MLSS) was 37 mL/g and 2.15 g/L on day 50, respectively. Rapid static feeding can accelerate granules formation by promoting the growth of heterotrophic bacteria, but the granules are unstable due to filamentous bacteria overgrowth. Fe addition can inhibit the growth of filamentous bacteria and promote the aggregation of functional bacteria (eg. Nitrosomonas, Nitrolancea, Paracoccus, Diaphorobacter) by enhancing the secretion of extracellular polymeric substances (EPS). This study provides a new way for AGS application in low-strength wastewater treatment.
Topics: Wastewater; Sewage; Waste Disposal, Fluid; Aerobiosis; Bioreactors; Nitrogen
PubMed: 38029821
DOI: 10.1016/j.envres.2023.117770 -
Environmental Research Jun 2024The key to the resource recycling of saline wastes in form of polyhydroxyalkanoates (PHA) is to enrich mixed cultures with salt tolerance and PHA synthesis ability....
The key to the resource recycling of saline wastes in form of polyhydroxyalkanoates (PHA) is to enrich mixed cultures with salt tolerance and PHA synthesis ability. However, the comparison of saline sludge from different sources and the salt tolerance mechanisms of salt-tolerant PHA producers need to be clarified. In this study, three kinds of activated sludge from different salinity environments were selected as the inoculum to enrich salt-tolerant PHA producers under aerobic dynamic feeding (ADF) mode with butyric acid dominated mixed volatile fatty acid as the substrate. The maximum PHA content (PHAm) reached 0.62 ± 0.01, 0.62 ± 0.02, and 0.55 ± 0.03 g PHA/g VSS at salinity of 0.5%, 0.8%, and 1.8%, respectively. Microbial community analysis indicated that Thauera, Paracoccus, and Prosthecobacter were dominant salt-tolerant PHA producers at low salinity, Thauera, NS9_marine, and SM1A02 were dominant salt-tolerant PHA producers at high salinity. High salinity and ADF mode had synergistic effects on selection and enrichment of salt-tolerant PHA producers. Combined correlation network with redundancy analysis indicated that trehalose synthesis genes and betaine related genes had positive correlation with PHAm, while extracellular polymeric substances (EPS) content had negative correlation with PHAm. The compatible solutes accumulation and EPS secretion were the main salt tolerance mechanisms of the PHA producers. Therefore, adding compatible solutes is an effective strategy to improve PHA synthesis in saline environment.
Topics: Polyhydroxyalkanoates; Salinity; Salt Tolerance; Sewage; Bacteria
PubMed: 38499223
DOI: 10.1016/j.envres.2024.118722 -
The Science of the Total Environment Mar 2024Autotrophic denitrification (AD) without carbon source is an inevitable choice for denitrification of municipal wastewater under the carbon peaking and carbon neutrality...
Autotrophic denitrification (AD) without carbon source is an inevitable choice for denitrification of municipal wastewater under the carbon peaking and carbon neutrality goals. This study first employed sulfur-tourmaline-AD (STAD) as an innovative nitrate removal trial technique in wastewater. STAD demonstrated a 2.23-fold increase in nitrate‑nitrogen (NO-N) removal rate with reduced nitrite‑nitrogen (NO-N) accumulation, effectively removing 99 % of nitrogen pollutants compared to sulfur denitrification. Some denitrifiers microorganisms that could secrete tyrosine, tryptophan, and aromatic protein (extracellular polymeric substances (EPS)). Moreover, according to the EPS composition and characteristics analysis, the secretion of loosely bound extracellular polymeric substances (LB-EPS) that bound to the bacterial endogenous respiration and enriched microbial abundance, was produced more in the STAD system, further improving the system stability. Furthermore, the addition of tourmaline (Tm) facilitated the discovery of a new genus (Paracoccus) that enhanced nitrate decomposition. Applying optimal electron donors through metabolic pathways and the microbial community helps to strengthen the AD process and treat low carbon/nitrogen ratio wastewater efficiently.
Topics: Wastewater; Denitrification; Nitrates; Electrons; Sulfur; Nitrogen; Carbon; Bioreactors; Silicates
PubMed: 38185169
DOI: 10.1016/j.scitotenv.2023.169847 -
Environmental Science and Pollution... Dec 2023Paracoccus sp. strain DMF (P. DMF from henceforth) is a gram-negative heterotroph known to tolerate and utilize high concentrations of N,N-dimethylformamide (DMF). The...
Paracoccus sp. strain DMF (P. DMF from henceforth) is a gram-negative heterotroph known to tolerate and utilize high concentrations of N,N-dimethylformamide (DMF). The work presented here elaborates on the metabolic pathways involved in the degradation of C1 compounds, many of which are well-known pollutants and toxic to the environment. Investigations on microbial growth and detection of metabolic intermediates corroborate the outcome of the functional genome analysis. Several classes of C1 compounds, such as methanol, methylated amines, aliphatic amides, and naturally occurring quaternary amines like glycine betaine, were tested as growth substrates. The detailed growth and kinetic parameter analyses reveal that P. DMF can efficiently aerobically degrade trimethylamine (TMA) and grow on quaternary amines such as glycine betaine. The results show that the mechanism for halotolerant adaptation in the presence of glycine betaine is dissimilar from those observed for conventional trehalose-mediated halotolerance in heterotrophic bacteria. In addition, a close genomic survey revealed the presence of a Co(I)-based substrate-specific corrinoid methyltransferase operon, referred to as mtgBC. This demethylation system has been associated with glycine betaine catabolism in anaerobic methanogens and is unknown in denitrifying aerobic heterotrophs. This report on an anoxic-specific demethylation system in an aerobic heterotroph is unique. Our finding exposes the metabolic potential for the degradation of a variety of C1 compounds by P. DMF, making it a novel organism of choice for remediating a wide range of possible environmental contaminants.
Topics: Dimethylformamide; Amides; Betaine; Paracoccus; Metabolic Networks and Pathways
PubMed: 38010547
DOI: 10.1007/s11356-023-30858-1 -
MSystems Feb 2024A genome scale metabolic model of the bacterium has been constructed. The model containing 972 metabolic genes, 1,371 reactions, and 1,388 unique metabolites has been...
A genome scale metabolic model of the bacterium has been constructed. The model containing 972 metabolic genes, 1,371 reactions, and 1,388 unique metabolites has been reconstructed. The model was used to carry out quantitative predictions of biomass yields on 10 different carbon sources under aerobic conditions. Yields on C1 compounds suggest that formate is oxidized by a formate dehydrogenase O, which uses ubiquinone as redox co-factor. The model also predicted the threshold methanol/mannitol uptake ratio, above which ribulose biphosphate carboxylase has to be expressed in order to optimize biomass yields. Biomass yields on acetate, formate, and succinate, when NO is used as electron acceptor, were also predicted correctly. The model reconstruction revealed the capability of to grow on several non-conventional substrates such as adipic acid, 1,4-butanediol, 1,3-butanediol, and ethylene glycol. The capacity to grow on these substrates was tested experimentally, and the experimental biomass yields on these substrates were accurately predicted by the model.IMPORTANCE has been broadly used as a model denitrifying organism. It grows on a large portfolio of carbon sources, under aerobic and anoxic conditions. These characteristics, together with its amenability to genetic manipulations, make a promising cell factory for industrial biotechnology. This paper presents and validates the first functional genome-scale metabolic model for , which is a key tool to enable as a platform for metabolic engineering and industrial biotechnology. Optimization of the biomass yield led to accurate predictions in a broad scope of substrates.
Topics: Paracoccus denitrificans; Bacteria; Oxidation-Reduction; Carbon; Formates
PubMed: 38180324
DOI: 10.1128/msystems.01077-23