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Bioresource Technology Jul 2023A highly efficient aerobic denitrifying microbe was isolated from sewage sludge by using a denitrifier enrichment strategy based on decreasing carbon content. The...
A highly efficient aerobic denitrifying microbe was isolated from sewage sludge by using a denitrifier enrichment strategy based on decreasing carbon content. The microbe was identified as Pseudomonas mendocina HITSZ-D1 (hereafter, D1). Investigation of the conditions under which D1 grew and denitrified revealed that it performed good growth and nitrate removal performance under a wide range of conditions. In particular, D1 rapidly removed all types of inorganic nitrogen without accumulation of the intermediate products nitrite and nitrous oxide. Overall, D1 showed a total nitrogen removal efficiency >96% at a C/N ratio of 8. The biotransformation modes and fates of three typical types of inorganic nitrogen were also assessed. Moreover, D1 had significantly higher denitrification efficiency and enzyme activities than other aerobic denitrifying microbes (Paracoccus denitrificans, Pseudomonas aeruginosa, and Pseudomonas putida). These results suggest that D1 has great potential for treating wastewater containing high concentrations of nitrogen.
Topics: Nitrites; Pseudomonas mendocina; Sewage; Denitrification; Nitrates; Nitrogen; Nitrification; Aerobiosis
PubMed: 37037332
DOI: 10.1016/j.biortech.2023.129039 -
MicroPublication Biology 2022experiences and microbiome have been shown to shape its responses to certain stimuli; a recent study found that grown on JUb39 exhibited increased attraction to that...
experiences and microbiome have been shown to shape its responses to certain stimuli; a recent study found that grown on JUb39 exhibited increased attraction to that same growth bacteria while also lowered repulsion to the odor 1-octanol (O’Donnell et al. 2020). This prompted us to ask whether other strains of bacteria could likewise alter responses to bacterial food and volatile chemicals. So, to expand upon current knowledge, we cultured wild-type (N2) on an unidentified ( sp?), (MSPm1), (MYb11), (JUb19), or strain ( sp?). After several generations, we examined how their choice of bacterial food was affected. In addition, we looked at their response to the olfactory stimuli 2-butanone; 2,3-butanedione; 2,3-pentanedione; and 2-nonanone, as well as their response to the gustatory stimulus sodium chloride. Interestingly, we found that growth on any of these bacterial strains led to their bacterial preferences and behavioral responses to 2-butanone; 2,3-pentanedione; diacetyl; and sodium chloride remaining unchanged. However, we also saw that showed a preference for MSPm1 and sp? to HB101, and HB101 to MYb11. Furthermore, worms that are grown on MSPm1 showed stronger attraction to a 1:10 dilution of 2-nonanone (AWB-sensed odorant) as compared to worms grown on the other bacterial strains.
PubMed: 35622520
DOI: 10.17912/micropub.biology.000535 -
Foodborne Pathogens and Disease Nov 2023The purpose of this research was to analyze the functional portraits and genomic features of carbapenem-resistant carrying and . The resistance mechanism of the strain...
The purpose of this research was to analyze the functional portraits and genomic features of carbapenem-resistant carrying and . The resistance mechanism of the strain was verified by experiments. Genomic data were aligned and analyzed in the NCBI database. Growth curve measurements were used to describe the growth characteristics of the bacteria. The virulence of strain was analyzed by serum killing assay and biofilm formation assay. Plasmid conjugation experiments were performed to verify the transferability of plasmids carrying drug-resistance genes. The strain was highly resistant to carbapenems. In addition, ST typing is unknown and has been submitted to Genebank. The strain carried two carbapenemase genes, including and . Among them, was located on a 5.62832 Mb chromosome, and was located on a 172.851 Kb transferable plasmid, which was a very close relative of pIMP-NY7610 in China. The strain also had a variety of virulence genes, which were expressed in the siderophore, capsule, pilus, alginate, flagella, etc. The study suggests that the functional portrait and genomic features of carbapenem-resistant harboring and are unique to China. This outcome represents antibiotic resistance exhibited in the genus by acquiring chromosomes and plasmid genes. The monitoring and supervision of antimicrobial usage must be strengthened since the multi-drug-resistant and moderately virulent will attract much attention in the near future.
Topics: Carbapenems; Pseudomonas mendocina; beta-Lactamases; Plasmids; Drug Resistance, Microbial; Microbial Sensitivity Tests; Genomics; China; Anti-Bacterial Agents
PubMed: 37729068
DOI: 10.1089/fpd.2023.0055 -
Chemosphere Nov 2022Soil that contained polybutylene adipate-co-terephthalate (PBAT) was incubated with Priestia megaterium, Pseudomonas mendocina, and Pseudomonas pseudoalcaligenes to...
Soil that contained polybutylene adipate-co-terephthalate (PBAT) was incubated with Priestia megaterium, Pseudomonas mendocina, and Pseudomonas pseudoalcaligenes to improve the biodegradative process of this polymer. The mixture of Pr. megaterium and Ps. mendocina was highly effective at biodegrading the PBAT, and after eight weeks of soil incubation, approximately 84% of the PBAT film weight was lost. Mixtures of the other two species also positively affected the synergistic degradation of PBAT film in the soil, but the mixture of three species had a negative effect. The residual PBAT film microstructure clearly demonstrated the degradation of PBAT, and the degree of degradation was related to the different species. Cleavage of the PBAT film ester bond after soil microbial action affected its properties. The incubation of PBAT in soil that contained these species affected soil dehydrogenase and soil lipase in particular. The secretion of lipase by these species could play an important role in the degradation of PBAT in the soil.
Topics: Adipates; Bacillus megaterium; Esters; Lipase; Oxidoreductases; Phthalic Acids; Polyenes; Polyesters; Polymers; Pseudomonas mendocina; Pseudomonas oleovorans; Pseudomonas pseudoalcaligenes; Soil
PubMed: 35850225
DOI: 10.1016/j.chemosphere.2022.135700 -
Journal of Hazardous Materials Feb 2021A cocultivation of the Pseudomonas mendocina with Actinomucor elegans was developed and investigated to improve the biodegradation of polylactic acid/polybutylene...
A cocultivation of the Pseudomonas mendocina with Actinomucor elegans was developed and investigated to improve the biodegradation of polylactic acid/polybutylene adipate-co-terephthalate (PLA/PBAT). And the coculture system could produce an efficient PLA/PBAT-degrading enzymes system to degrade PLA/PBAT films. The results showed that the protease activity (11.50 U/mL) and lipase activity (40.46 U/mL) of the coculture exceeded that of the monoculture (P. mendocina of 7.31 U/mL, A. elegans of 32.47 U/mL). The degradation rate of PLA/PBAT films using the coculture system was 18.95 w% within 5 days, which was considerably higher than that of P. mendocina (12.94 w%) and A. elegans (9.27 w%) individually, suggesting that P. mendocina and A. elegans had synergistic degradation. In addition, P. mendocina and A. elegans could secrete proteases and lipases, respectively, which could catalyze the ester bonds of PLA and PBAT in PLA/PBAT films, respectively, and hydrolyze them into different monomers and oligomers as nutrition sources. Therefore, the PLA/PBAT films could be completely degraded. In this study, the PLA/PBAT films were efficiently degraded in the coculture system for the first time, which significantly improved the biodegradation of PLA/PBAT films.
Topics: Adipates; Coculture Techniques; Mucorales; Phthalic Acids; Polyenes; Polyesters; Pseudomonas mendocina
PubMed: 33264878
DOI: 10.1016/j.jhazmat.2020.123679 -
3 Biotech Nov 2019was identified as a novel endophytic isolate of with squalene cyclase activity. The PCR amplification of squalene hopene cyclase () gene from the isolate with the...
was identified as a novel endophytic isolate of with squalene cyclase activity. The PCR amplification of squalene hopene cyclase () gene from the isolate with the primers PA1/PA2 showed a band at 1980 bp specific for the enzyme squalene hopene cyclase. The in silico translation of the squalene hopene cyclase gene showed 96% sequence similarity with squalene hopene cyclase of (WP-060782422). Docking studies of the template and the modeled protein with the ligand squalene showed that the main interacting residues were Asp376 and Asp377. Squalene hopene cyclase template 1 sqc.1A sequence from was used as the template for docking experiments. The gene coding for squalene hopene cyclase from has been cloned in pET-28a vector to produce recombinant vector and was expressed in BL21 (DE3) expression system. Squalene hopene cyclase enzyme was isolated, purified and the molecular weight was confirmed by SDS-PAGE as 75 KDa.
PubMed: 31588405
DOI: 10.1007/s13205-019-1901-7 -
Bioresource Technology Jan 2021Six bacterial strains with simultaneous nitrification-denitrification abilities were isolated from a Beijing sewage treatment plant to improve nitrogen biodegradation...
Six bacterial strains with simultaneous nitrification-denitrification abilities were isolated from a Beijing sewage treatment plant to improve nitrogen biodegradation efficiency. One of these strains, X49, was identified as Pseudomonas mendocina, and was characterized as the best strain with which to rapidly degrade a high concentration of inorganic nitrogen. X49 completely converted 5-100 mg.L of ammonia in 12 h, with no nitrite accumulation; the maximum removal rate of 26.39 mg (N).L.h was achieved between 4 h and 6 h. In 16 h, the strain removed 100 mg.L nitrite and 72.61 mg.L nitrate under aerobic conditions, at degredation rates which reached 4.54 and 6.25 mg (N).L.h, respectively. Our results suggest that P. mendocina X49 achieved efficient and simultaneous nitrification and denitrification ability under heterotrophic aerobic conditions.
Topics: Aerobiosis; Ammonium Compounds; Beijing; Denitrification; Heterotrophic Processes; Nitrification; Nitrites; Nitrogen; Pseudomonas mendocina
PubMed: 33038648
DOI: 10.1016/j.biortech.2020.124198 -
Scientific Reports Dec 2022PmlR2, a class II LitR/CarH family transcriptional regulator, and PmSB-LOV, a "short" LOV-type blue light photoreceptor, are adjacently encoded in Pseudomonas mendocina...
PmlR2, a class II LitR/CarH family transcriptional regulator, and PmSB-LOV, a "short" LOV-type blue light photoreceptor, are adjacently encoded in Pseudomonas mendocina NBRC 14162. An effector protein for the "short" LOV-type photoreceptor in Pseudomonas has not yet been identified. Here, we show that PmlR2 is an effector protein of PmSB-LOV. Transcriptional analyses revealed that the expression of genes located near pmlR2 and its homolog gene, pmlR1, was induced in response to illumination. In vitro DNA-protein binding analyses showed that recombinant PmlR2 directly binds to the promoter region of light-inducible genes. Furthermore PmSB-LOV exhibited a typical LOV-type light-induced spectral change. Gel-filtration chromatography demonstrated that the illuminated PmSB-LOV was directly associated with PmlR2, whereas non-illuminated proteins did not interact. The inhibition of PmlR2 function following PmSB-LOV binding was verified by surface plasmon resonance: the DNA-binding ability of PmlR2 was specifically inhibited in the presence of blue light-illuminated-PmSB-LOV. An In vitro transcription assay showed a dose-dependent reduction in PmlR2 repressor activity in the presence of illuminated PmSB-LOV. Overall, evidence suggests that the DNA-binding activity of PmlR2 is inhibited by its direct association with blue light-activated PmSB-LOV, enabling transcription of light-inducible promoters by RNA polymerase.
Topics: Pseudomonas mendocina; Bacterial Proteins; Promoter Regions, Genetic; Protein Binding; DNA
PubMed: 36526696
DOI: 10.1038/s41598-022-26254-3 -
Environmental Research Aug 2023Nitrogen (N) and phosphorous (P) removal by a single bacterium could improve the biological reaction efficiency and reduce the operating cost and complexity in...
Nitrogen (N) and phosphorous (P) removal by a single bacterium could improve the biological reaction efficiency and reduce the operating cost and complexity in wastewater treatment plants (WWTPs). Here, an isolated strain was identified as Pseudomonas mendocina SCZ-2 and showed high performance of heterotrophic nitrification (HN) and aerobic denitrification (AD) without intermediate accumulation. During the AD process, the nitrate removal efficiency and rate reached a maximum of 100% and 47.70 mg/L/h, respectively, under optimal conditions of sodium citrate as carbon source, a carbon-to-nitrogen ratio of 10, a temperature of 35 °C, and shaking a speed of 200 rpm. Most importantly, the strain SCZ-2 could rapidly and simultaneously eliminate N and P with maximum NH-N, NO-N, NO-N, and PO-P removal rates of 14.38, 17.77, 20.13 mg N/L/h, and 2.93 mg P/L/h, respectively. Both the N and P degradation curves matched well with the modified Gompertz model. Moreover, the amplification results of functional genes, whole genome sequencing, and enzyme activity tests provided theoretical support for simultaneous N and P removal pathways. This study deepens our understanding of the role of HN-AD bacteria and provides more options for simultaneous N and P removal from actual sewage.
Topics: Denitrification; Pseudomonas mendocina; Nitrogen; Aerobiosis; Nitrification; Phosphorus; Carbon; Nitrites
PubMed: 37149028
DOI: 10.1016/j.envres.2023.116062 -
International Journal of Biological... Nov 2020Pseudomonas mendocina NK-01 previously isolated by our lab is able to accumulate medium-chain-length polyhydroxyalkanoate (mcl-PHA) intracellularly and secrete alginate...
Pseudomonas mendocina NK-01 previously isolated by our lab is able to accumulate medium-chain-length polyhydroxyalkanoate (mcl-PHA) intracellularly and secrete alginate oligosaccharide (AO) to the extracellular milieu. The present study aimed at investigating whether improved production of mcl-PHA and AO by P. mendocina can be accomplished by genome reduction. In this study, 14 large genomic fragments accounting for 7.7% of the genome of P. mendocina NK-01 were sequentially deleted to generate a series of genome-reduced strains by an upp-based markerless knockout method. As a result, the intracellular ATP/ADP ratio of the strain NKU421 with the largest deletion improved by 11 times compared to NK-01. More importantly, the mcl-PHA and AO yields of NKU421 increased by 114.8% and 27.8%, respectively. Enhancing mcl-PHA and AO production by NKU421 may be attributed to improved transcriptional levels of PHA synthase genes and AO secretion-related genes. The present study suggests that rational reduction of bacterial genome is a feasible approach to construct an optimal chassis for enhanced production of bacterial metabolites. In the future, further reduction of the NKU421 genome can be expected to create high-performance chassis for the development of microbial cell factories.
Topics: Acyltransferases; Alginates; Genome, Bacterial; Metabolic Engineering; Oligosaccharides; Polyhydroxyalkanoates; Pseudomonas mendocina
PubMed: 32941898
DOI: 10.1016/j.ijbiomac.2020.09.067