Bacterial community dynamics and biodegradation processes were examined in a highly creosote-contaminated soil undergoing a range of laboratory-based bioremediation treatments. The dynamics of the eubacterial community, the number of heterotrophs and polycyclic aromatic hydrocarbon (PAH) degraders, and the total petroleum hydrocarbon (TPH) and PAH concentrations were monitored during the bioremediation process. TPH and PAHs were significantly degraded in all treatments (72 to 79% and 83 to 87%, respectively), and the biodegradation values were higher when nutrients were not added, especially for benzo(a)anthracene and chrysene. The moisture content and aeration were determined to be the key factors associated with PAH bioremediation. Neither biosurfactant addition, bioaugmentation, nor ferric octate addition led to differences in PAH or TPH biodegradation compared to biodegradation with nutrient treatment. All treatments resulted in a high first-order degradation rate during the first 45 days, which was markedly reduced after 90 days. A sharp increase in the size of the heterotrophic and PAH-degrading microbial populations was observed, which coincided with the highest rates of TPH and PAH biodegradation. At the end of the incubation period, PAH degraders were more prevalent in samples to which nutrients had not been added. Denaturing gradient gel electrophoresis analysis and principal-component analysis confirmed that there was a remarkable shift in the composition of the bacterial community due to both the biodegradation process and the addition of nutrients. At early stages of biodegradation, the alpha-Proteobacteria group (genera Sphingomonas and Azospirillum) was the dominant group in all treatments. At later stages, the gamma-Proteobacteria group (genus Xanthomonas), the alpha-Proteobacteria group (genus Sphingomonas), and the Cytophaga-Flexibacter-Bacteroides group (Bacteroidetes) were the dominant groups in the nonnutrient treatment, while the gamma-Proteobacteria group (genus Xathomonas), the beta-Proteobacteria group (genera Alcaligenes and Achromobacter), and the alpha-Proteobacteria group (genus Sphingomonas) were the dominant groups in the nutrient treatment. This study shows that specific bacterial phylotypes are associated both with different phases of PAH degradation and with nutrient addition in a preadapted PAH-contaminated soil. Our findings also suggest that there are complex interactions between bacterial species and medium conditions that influence the biodegradation capacity of the microbial communities involved in bioremediation processes.
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http://dx.doi.org/10.1128/AEM.71.11.7008-7018.2005 | DOI Listing |
Genome Biol
January 2025
The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, 2800, Denmark.
Background: Streptomyces is a highly diverse genus known for the production of secondary or specialized metabolites with a wide range of applications in the medical and agricultural industries. Several thousand complete or nearly complete Streptomyces genome sequences are now available, affording the opportunity to deeply investigate the biosynthetic potential within these organisms and to advance natural product discovery initiatives.
Results: We perform pangenome analysis on 2371 Streptomyces genomes, including approximately 1200 complete assemblies.
Proc Biol Sci
January 2025
The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, People's Republic of China.
Plants have evolved different life-history strategies to overcome limited amounts of available resources; however, when and how divergent strategies of sexual reproduction evolved in early land plants are not well understood. As one of the notable and vital components of early terrestrial vegetation, the Zosterophyllopsida and its type genus reached maximum species diversity during the Pragian (Early Devonian; 410.8-407.
View Article and Find Full Text PDFMedicine (Baltimore)
November 2024
Department of Endocrinology, The First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou, P. R. China.
Studies have shown that gut microbiota (GM) and its metabolites, short-chain fatty acids (SCFAs), are associated with the development of postmenopausal osteoporosis (PMO). This study explored the clinical and laboratory evidence of the relationship of GM and SCFAs to PMO and attempted to determine the potential mechanism of action. 18 patients (Collected from the First Affiliated Hospital of Guangdong Pharmaceutical University between January 2021 and August 2021) were included in this retrospective study, including 10 PMO women and 8 healthy young women as the healthy control (HC) group from Guangzhou, China.
View Article and Find Full Text PDFPLoS One
January 2025
Staatliche Naturwissenschaftliche Sammlungen Bayerns-Bayerische Staatssammlung für Paläontologie und Geologie, Munich, Germany.
The first partial skeleton of a carcharodontosaurid theropod was described from the Egyptian Bahariya Oasis by Ernst Stromer in 1931. Stromer referred the specimen to the species Megalosaurus saharicus, originally described on the basis of isolated teeth from slightly older rocks in Algeria, under the new genus name Carcharodontosaurus saharicus. Unfortunately, almost all of the material from the Bahariya Oasis, including the specimen of Carcharodontosaurus was destroyed during World War II.
View Article and Find Full Text PDFMicrosc Res Tech
January 2025
Faculty of Science, Department of Molecular Biology and Genetics, Pamukkale University, Denizli, Türkiye.
This study investigates the pollen morphology of 13 taxa of Turkish Gentiana using a statistical approach, contributing to their taxonomy. The aim is to elucidate the palynological characteristics of the taxa and to reveal their contributions to the systematic understanding of the genus Gentiana. The pollen grains are monad, radially symmetrical, isopolar, and tricolporate.
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