Biofilms are a major source of human pathogenic Legionella pneumophila in aquatic systems. In this study, we investigated the capacity of L. pneumophila to colonize floating biofilms and the impact of Acanthamoeba castellanii on the replication of biofilm-associated Legionella. Biofilms were grown in Petri dishes and consisted of Aeromonas hydrophila, Escherichia coli, Flavobacterium breve, and Pseudomonas aeruginosa. Six hours following inoculation, Legionella were detected in floating biofilms in mean concentrations of 1.4 x 10(4) cells/cm(2 )(real-time polymerase chain reaction) and 8.3 x 10(2) CFU/cm(2 )(culture). Two-way analysis of variance tests and fluorescent in situ hybridization clearly proved that increased biofilm-associated L. pneumophila concentrations were the result of intracellular replication in A. castellanii. Forty-eight hours after the introduction of A. castellanii in the Petri dishes, 90 +/- 0.8% of the amoebae (infection rate) were completely filled with highly metabolic active L. pneumophila (mean infection intensity).
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Environ Microbiol Rep
December 2024
Area of Microbiology, Department of Health Sciences, Faculty of Experimental Sciences, University of Jaén, Jaén, Spain.
Spore-forming organisms are an integral component of the rhizosphere, providing plants with significant advantages. Previous studies determined the antimicrobial activity of the olive sporobiota, identifying five candidates of particular relevance, belonging to the Bacillus subtilis, Peribacillus simplex and Bacillus cereus clade. This study aimed to determine their biotechnological properties, safety aspects, spore structure and resistance, and interaction with the environment through a combined microbiological and genomic approach.
View Article and Find Full Text PDFBiosensors (Basel)
November 2024
Université de Lorraine, CNRS, LIEC, F-54000 Nancy, France.
ISME Commun
January 2024
Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju 28644, Republic of Korea.
Soil microorganisms often thrive as microcolonies or biofilms within pores of soil aggregates exposed to the soil atmosphere. However, previous studies on the physiology of soil ammonia-oxidizing microorganisms (AOMs), which play a critical role in the nitrogen cycle, were primarily conducted using freely suspended AOM cells (planktonic cells) in liquid media. In this study, we examined the growth of two representative soil ammonia-oxidizing archaea (AOA), EN76 and "" MY2, and a soil ammonia-oxidizing bacterium, ATCC 19718 on polycarbonate membrane filters floated on liquid media to observe their adaptation to air-exposed solid surfaces.
View Article and Find Full Text PDFScientifica (Cairo)
October 2024
Department of Applied Life Sciences, Faculty of Agriculture, Shizuoka University, Shizuoka 422-8529, Japan.
Biofilms are major virulence factors formed by pathogenic bacteria to invade their host and maintain their colony. While biofilms usually develop on diverse solid surfaces, floating biofilms, also called pellicles, are formed at the air-liquid interface. To address the problem of biofilm formation by bacterial pathogens, honey has been extensively studied.
View Article and Find Full Text PDFUnlabelled: Many fundamental insights into microbiology have come from imaging, which is typically synonymous with optical techniques. However, the sample preparation needed for many optical microscopy methods such as labeling, fixing, or genetic modification, limits the range of species and environments we can investigate. Here we demonstrate the use of electrical capacitance measurements as a non-optical method for imaging live microbial samples.
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