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Pest Management Science Apr 2024Aedes aegypti is a widespread mosquito in tropical and subtropical regions that causes significant mortality and morbidity in humans by transmitting diseases, such as...
BACKGROUND
Aedes aegypti is a widespread mosquito in tropical and subtropical regions that causes significant mortality and morbidity in humans by transmitting diseases, such as dengue fever and Zika virus disease. Synthetic insecticides, such as pyrethroids, have been used to control Ae. aegypti, but these insecticides can also affect nontarget organisms and contaminate soil and water. This study aimed to investigate the mosquitocidal activity of Pseudomonas mosselii isolated from pond sludge against larvae of Ae. aegypti.
RESULTS
Based on the initial results, similar time-course profiles were obtained for the mosquitocidal activity of the bacterial culture and its supernatant, and the pellet resuspended in Luria-Bertani (LB) medium also showed delayed toxicity. These results imply that the toxic component can be released into the medium from live bacteria. Further research indicated that the toxic component appeared in the supernatant approximately 4 h after a 3-mL stock was cultured in 200 mL of LB medium. The stabilities of the P. mosselii culture and supernatant stored at different temperatures were also evaluated, and the best culture stability was obtained at 28 °C and supernatant stability at 4 °C. The bacterial culture and supernatant were toxic to larvae and pupae of not only susceptible Ae. aegypti but also pyrethroid-resistant strains.
CONCLUSION
This study highlights the value of the mosquitocidal activity of P. mosselii, which has potential as an alternative insecticide to control pyrethroid-resistant Ae. aegypti in the field. © 2024 Society of Chemical Industry.
PubMed: 38634536
DOI: 10.1002/ps.8139 -
Polymers Nov 2023The treatment and reuse of wastewater are crucial for the effective utilization and protection of global water resources. Polycyclic aromatic hydrocarbons (PAHs), as one...
The treatment and reuse of wastewater are crucial for the effective utilization and protection of global water resources. Polycyclic aromatic hydrocarbons (PAHs), as one of the most common organic pollutants in industrial wastewater, are difficult to remove due to their relatively low solubility and bioavailability in the water environment. However, biosurfactants with both hydrophilic and hydrophobic groups are effective in overcoming these difficulties. Therefore, a biosurfactant-producing strain MP-6 was isolated in this study to enhance the bioavailability and biodegradation of PAHs, especially high-molecular-weight PAHs (HMW-PAHs). FTIR and LC-MS analysis showed that the MP-6 surfactant belongs to rhamnolipids, a type of biopolymer, which can reduce the water surface tension from 73.20 mN/m to 30.61 mN/m at a critical micelle concentration (CMC = 93.17 mg/L). The enhanced solubilization and biodegradation of PAHs, particularly HMW-PAHs (when MP-6 was introduced), were also demonstrated in experiments. Furthermore, comprehensive environmental stress tolerance tests were conducted to confirm the robustness of the MP-6 biosurfactant, which signifies the potential adaptability and applicability of this biosurfactant in diverse environmental remediation scenarios. The results of this study, therefore, have significant implications for future applications in the treatment of wastewater containing HMW-PAHs, such as coking wastewater.
PubMed: 38232027
DOI: 10.3390/polym15234571 -
Toxics Dec 2023The use of bacteria of the genus -destructors of persistent pollutants for biotechnologies of environmental purification-is an interesting area of research. The aim of...
The use of bacteria of the genus -destructors of persistent pollutants for biotechnologies of environmental purification-is an interesting area of research. The aim of this work was to study the potential of strain 5(3) isolated from pesticide-contaminated soil as a degrader of C-C perfluorocarboxylic acids (PFCAs) and analyze its complete genome. The genome of the strain has been fully sequenced. It consists of a chromosome with a length of 5,676,241 b.p. and containing a total of 5134 genes, in particular, haloalkane dehalogenase gene (), haloacetate dehalogenase H-1 gene (), fluoride ion transporter gene () and alkanesulfonate monooxygenase gene (), responsible for the degradation of fluorinated compounds. The strain 5(3) for was cultivated for 7 days in a liquid medium with various C-C PFCAs as the sole source of carbon and energy, and completely disposed of them. The results of LC-MS analysis showed that the transformation takes place due to perfluorohexanoic acid with the release of various levels of stoichiometry (depending on PFCA) of fluorine ion mineralization indicators determined by ion chromatography. Thus, strain 5(3) demonstrates a genetically confirmed high potential for the decomposition of C-C PFCA.
PubMed: 38133402
DOI: 10.3390/toxics11121001 -
Microbiology Resource Announcements Dec 2023The P 5(3) strain is a potential degrader of persistent perfluorinated pollutants, particularly C-C perfluorinated acids. The genome of the strain has been fully...
The P 5(3) strain is a potential degrader of persistent perfluorinated pollutants, particularly C-C perfluorinated acids. The genome of the strain has been fully sequenced. It consists of a chromosome with a length of 5,676,241 base pairs and a G-C content of 64.38%.
PubMed: 37955621
DOI: 10.1128/MRA.00839-23 -
Canadian Journal of Microbiology Jan 2024Cold stress is an important factor limiting rice production and distribution. Identifying factors that contribute to cold tolerance in rice is of primary importance....
Cold stress is an important factor limiting rice production and distribution. Identifying factors that contribute to cold tolerance in rice is of primary importance. While some plant specific genetic factors involved in cold tolerance have been identified, the role of the rice microbiome remains unexplored. In this study, we evaluated the influence of plant growth promoting bacteria (PGPB) with the ability of phosphate solubilization on rice cold tolerance and survival. To reach this goal, inoculated and uninoculated 2-week-old seedlings were cold stressed and evaluated for survival and other phenotypes such as electrolyte leakage (EL) and necessary elements for cold tolerance. The results of this study showed that of the five bacteria, , improved both and varietal plants' survival and decreased EL, indicating increased membrane integrity. We observed different possible cold tolerance mechanisms in and plants such as increases in proline and reduced glutathione levels, respectively. This bacterium also improved the shoot growth of cold exposed plants during the recovery period. This study confirmed the host genotype dependent activity of and indicated that there is an interaction between specific plant genes and bacterial genes that causes different plant responses to cold stress.
Topics: Glutathione; Oryza; Proline; Genotype; Cold Temperature
PubMed: 37699259
DOI: 10.1139/cjm-2023-0030 -
Bioresource Technology Sep 2023This study was designed to develop a cellulase-producing bacterial consortium (CBC) from wood-feeding termites that could effectively degrade willow sawdust (WSD) and...
This study was designed to develop a cellulase-producing bacterial consortium (CBC) from wood-feeding termites that could effectively degrade willow sawdust (WSD) and consequently enhance methane production. The bacterial strains Shewanella sp. SSA-1557, Bacillus cereus SSA-1558, and Pseudomonas mosselii SSA-1568 exhibited significant cellulolytic activity. Their CBC consortium showed positive effects on cellulose bioconversion, resulting in accelerated WSD degradation. After nine days of pretreatment, the WSD had lost 63%, 50%, and 28% of its cellulose, hemicellulose, and lignin, respectively. The hydrolysis rate of treated WSD (352 mg/g) was much higher than that of untreated WSD (15.2 mg/g). The highest biogas production (66.1 NL/kg VS) with 66% methane was observed in the anaerobic digester M-2, which contained a combination of pretreated WSD and cattle dung in a 50/50 ratio. The findings will enrich knowledge for the development of cellulolytic bacterial consortia from termite guts for biological wood pretreatment in lignocellulosic anaerobic digestion biorefineries.
Topics: Animals; Cattle; Isoptera; Salix; Wood; Cellulase; Lignin; Cellulose; Bacteria; Biofuels; Methane; Anaerobiosis
PubMed: 37244303
DOI: 10.1016/j.biortech.2023.129232 -
Nature Communications Feb 2023Natural products largely produced by Pseudomonads-like soil-dwelling microorganisms are a consistent source of antimicrobial metabolites and pesticides. Herein we report...
Natural products largely produced by Pseudomonads-like soil-dwelling microorganisms are a consistent source of antimicrobial metabolites and pesticides. Herein we report the isolation of Pseudomonas mosselii strain 923 from rice rhizosphere soils of paddy fields, which specifically inhibit the growth of plant bacterial pathogens Xanthomonas species and the fungal pathogen Magnaporthe oryzae. The antimicrobial compound is purified and identified as pseudoiodinine using high-resolution mass spectra, nuclear magnetic resonance and single-crystal X-ray diffraction. Genome-wide random mutagenesis, transcriptome analysis and biochemical assays define the pseudoiodinine biosynthetic cluster as psdABCDEFG. Pseudoiodinine biosynthesis is proposed to initiate from guanosine triphosphate and 1,6-didesmethyltoxoflavin is a biosynthetic intermediate. Transposon mutagenesis indicate that GacA is the global regulator. Furthermore, two noncoding small RNAs, rsmY and rsmZ, positively regulate pseudoiodinine transcription, and the carbon storage regulators CsrA2 and CsrA3, which negatively regulate the expression of psdA. A 22.4-fold increase in pseudoiodinine production is achieved by optimizing the media used for fermentation, overexpressing the biosynthetic operon, and removing the CsrA binding sites. Both of the strain 923 and purified pseudoiodinine in planta inhibit the pathogens without affecting the rice host, suggesting that pseudoiodinine can be used to control plant diseases.
Topics: Bacterial Proteins; Pseudomonas; RNA, Untranslated; Operon; Plant Diseases; Oryza
PubMed: 36759518
DOI: 10.1038/s41467-023-36433-z -
Antibiotics (Basel, Switzerland) Nov 2022The emergence of drug resistant microbes over recent decades represents one of the greatest threats to human health; the resilience of many of these organisms can be...
The emergence of drug resistant microbes over recent decades represents one of the greatest threats to human health; the resilience of many of these organisms can be attributed to their ability to produce biofilms. Natural products have played a crucial role in drug discovery, with microbial natural products in particular proving a rich and diverse source of antimicrobial agents. During antimicrobial activity screening, the strain P33 was found to inhibit the growth of multiple pathogens. Following chemical investigation of this strain, pseudopyronines A-C were isolated as the main active principles, with all three pseudopyronines showing outstanding activity against . The analogue pseudopyronine C, which has not been well-characterized previously, displayed sub-micromolar activity against , and . Moreover, the inhibitory abilities of the pseudopyronines against the biofilms of were further studied. The results indicated all three pseudopyronines could directly reduce the growth of biofilm in both adhesion stage and maturation stage, displaying significant activity at micromolar concentrations.
PubMed: 36421300
DOI: 10.3390/antibiotics11111655 -
Journal of Natural Products Nov 2022The secondary metabolite pseudopyronine B, isolated from P33, was biotransformed by human P450 enzymes, heterologously expressed in the fission yeast . Small-scale...
The secondary metabolite pseudopyronine B, isolated from P33, was biotransformed by human P450 enzymes, heterologously expressed in the fission yeast . Small-scale studies confirmed that both CYP4F2 and CYP4F3A were capable of oxidizing the substrate, with the former achieving a higher yield. In larger-scale studies using CYP4F2, three new oxidation products were obtained, the structures of which were elucidated by UV-vis, 1D and 2D NMR, and HR-MS spectroscopy. These corresponded to hydroxylated, carboxylated, and ester derivatives (-) of pseudopyronine B, all of which had been oxidized exclusively at the ω-position of the C-6 alkyl chain. homology modeling experiments highlighted key interactions between oxygen atoms of the pyrone ring and two serine residues and a histidine residue of CYP4F2, which hold the substrate in a suitable orientation for oxidation at the terminus of the C-6 alkyl chain. Additional modeling studies with all three pseudopyronines revealed that the seven-carbon alkyl chain of pseudopyronine B was the perfect length for oxidation, with the terminal carbon lying close to the heme iron. The antibacterial activity of the substrates and three oxidation products was also assessed, revealing that oxidation at the ω-position removes all antimicrobial activity. This study both increases the range of known substrates for human CYF4F2 and CYP4F3A enzymes and demonstrates their utility in producing additional natural product derivatives.
Topics: Humans; Anti-Bacterial Agents; Biotransformation; Cytochrome P-450 Enzyme System; Cytochrome P450 Family 4; Hydroxylation; Oxidation-Reduction; Pyrones; Schizosaccharomyces
PubMed: 36327116
DOI: 10.1021/acs.jnatprod.2c00616 -
Biology Aug 2022The environmental bacterium produces antagonistic secondary metabolites with inhibitory effects on multiple plant pathogens, including the causal agent of bacterial...
The environmental bacterium produces antagonistic secondary metabolites with inhibitory effects on multiple plant pathogens, including the causal agent of bacterial wilt. In this study, an engineered strain was generated to express , which determines the incompatible interactions with tobacco plants. The gene, together with its native promoter, was integrated into the chromosome. The resulting strain showed no difference in antimicrobial activity against . Promoter-LacZ fusion and RT-PCR experiments demonstrated that the gene was transcribed in culture media. Compared with that of the wild type, the engineered strain reduced the disease index by 9.1% for bacterial wilt on tobacco plants. A transcriptome analysis was performed to identify differentially expressed genes in tobacco plants, and the results revealed that ethylene- and jasmonate-dependent defense signaling pathways were induced. These data demonstrates that the engineered expressing can improve biological control against tobacco bacterial wilt by the activation of host defense responses.
PubMed: 36009798
DOI: 10.3390/biology11081170