scholarly journals In situ modelling of biofilm formation in a hydrothermal spring cave

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Dóra Anda ◽  
Attila Szabó ◽  
Petra Kovács-Bodor ◽  
Judit Makk ◽  
Tamás Felföldi ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Biofilm Formation ◽  
Taxonomic Composition ◽  
Metabolic Potential ◽  
Stagnant Water ◽  
Complex Processes ◽  
Hydrothermal Spring ◽  
Biofilm Development ◽  
Buda Thermal Karst

AbstractAttachment of microorganisms to natural or artificial surfaces and the development of biofilms are complex processes which can be influenced by several factors. Nevertheless, our knowledge on biofilm formation in karstic environment is quite incomplete. The present study aimed to examine biofilm development for a year under controlled conditions in quasi-stagnant water of a hydrothermal spring cave located in the Buda Thermal Karst System (Hungary). Using a model system, we investigated how the structure of the biofilm is formed from the water and also how the growth rate of biofilm development takes place in this environment. Besides scanning electron microscopy, next-generation DNA sequencing was used to reveal the characteristic taxa and major shifts in the composition of the bacterial communities. Dynamic temporal changes were observed in the structure of bacterial communities. Bacterial richness and diversity increased during the biofilm formation, and 9–12 weeks were needed for the maturation. Increasing EPS production was also observed from the 9–12 weeks. The biofilm was different from the water that filled the cave pool, in terms of the taxonomic composition and metabolic potential of microorganisms. In these karstic environments, the formation of mature biofilm appears to take place relatively quickly, in a few months.

scholarly journals Effects of in situ Remediation With Nanoscale Zero Valence Iron on the Physicochemical Conditions and Bacterial Communities of Groundwater Contaminated With Arsenic

2021 ◽  
Vol 12 ◽  
Author(s):  
Ana Castaño ◽  
Alexander Prosenkov ◽  
Diego Baragaño ◽  
Nerea Otaegui ◽  
Herminio Sastre ◽  
...  
Keyword(s):  
Organic Contaminants ◽  
Bacterial Communities ◽  
Intergenic Spacer ◽  
Cost Effective ◽  
Taxonomic Composition ◽  
Sulfate Reducing ◽  
Oxidation Reduction ◽  
Before And After ◽  
Complete Study

Nanoscale Zero-Valent Iron (nZVI) is a cost-effective nanomaterial that is widely used to remove a broad range of metal(loid)s and organic contaminants from soil and groundwater. In some cases, this material alters the taxonomic and functional composition of the bacterial communities present in these matrices; however, there is no conclusive data that can be generalized to all scenarios. Here we studied the effect of nZVI application in situ on groundwater from the site of an abandoned fertilizer factory in Asturias, Spain, mainly polluted with arsenic (As). The geochemical characteristics of the water correspond to a microaerophilic and oligotrophic environment. Physico-chemical and microbiological (cultured and total bacterial diversity) parameters were monitored before and after nZVI application over six months. nZVI treatment led to a marked increase in Fe(II) concentration and a notable fall in the oxidation-reduction potential during the first month of treatment. A substantial decrease in the concentration of As during the first days of treatment was observed, although strong fluctuations were subsequently detected in most of the wells throughout the six-month experiment. The possible toxic effects of nZVI on groundwater bacteria could not be clearly determined from direct observation of those bacteria after staining with viability dyes. The number of cultured bacteria increased during the first two weeks of the treatment, although this was followed by a continuous decrease for the following two weeks, reaching levels moderately below the initial number at the end of sampling, and by changes in their taxonomic composition. Most bacteria were tolerant to high As(V) concentrations and showed the presence of diverse As resistance genes. A more complete study of the structure and diversity of the bacterial community in the groundwater using automated ribosomal intergenic spacer analysis (ARISA) and sequencing of the 16S rRNA amplicons by Illumina confirmed significant alterations in its composition, with a reduction in richness and diversity (the latter evidenced by Illumina data) after treatment with nZVI. The anaerobic conditions stimulated by treatment favored the development of sulfate-reducing bacteria, thereby opening up the possibility to achieve more efficient removal of As.

scholarly journals Inhibition of Candida albicans Biofilm Formation by Farnesol, a Quorum-Sensing Molecule

2002 ◽  
Vol 68 (11) ◽  
pp. 5459-5463 ◽  
Author(s):  
Gordon Ramage ◽  
Stephen P. Saville ◽  
Brian L. Wickes ◽  
José L. López-Ribot
Keyword(s):  
Candida Albicans ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Northern Blot Analysis ◽  
Adherent Cell ◽  
Naturally Occurring ◽  
Biofilm Development ◽  
Further Development ◽  
Quorum Sensing Molecule

ABSTRACT Farnesol is a quorum-sensing molecule that inhibits filamentation in Candida albicans. Both filamentation and quorum sensing are deemed to be important factors in C. albicans biofilm development. Here we examined the effect of farnesol on C. albicans biofilm formation. C. albicans adherent cell populations (after 0, 1, 2, and 4 h of adherence) and preformed biofilms (24 h) were treated with various concentrations of farnesol (0, 3, 30, and 300 μM) and incubated at 37°C for 24 h. The extent and characteristics of biofilm formation were then assessed microscopically and with a semiquantitative colorimetric technique based on the use of 2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide. The results indicated that the effect of farnesol was dependent on the concentration of this compound and the initial adherence time, and preincubation with 300 μM farnesol completely inhibited biofilm formation. Supernatant media recovered from mature biofilms inhibited the ability of planktonic C. albicans to form filaments, indicating that a morphogenetic autoregulatory compound is produced in situ in biofilms. Northern blot analysis of RNA extracted from cells in biofilms indicated that the levels of expression of HWP1, encoding a hypha-specific wall protein, were decreased in farnesol-treated biofilms compared to the levels in controls. Our results indicate that farnesol acts as a naturally occurring quorum-sensing molecule which inhibits biofilm formation, and we discuss its potential for further development and use as a novel therapeutic agent.

Biofilm Formation by Listeria monocytogenes Utilizes a Primary Colonizing Microorganism in Flowing Systems

1993 ◽  
Vol 56 (12) ◽  
pp. 1022-1028 ◽  
Author(s):  
KYLE C. SASAHARA ◽  
EDMUND A. ZOTTOLA
Keyword(s):  
Electron Microscopy ◽  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Pseudomonas Fragi ◽  
Transmission Electron ◽  
Test Organisms ◽  
Pure Cultures ◽  
Inert Surfaces ◽  
Biofilm Development

Listeria monocytogenes serotype 3a and Pseudomonas fragi ATCC 4973 were examined for attachment capability and biofilm development on glass coverslips under flowing systems. Tryptic soy broth supplemented with yeast extract was the growth medium. A continuous flow slide chamber was developed for in situ observations using phase-contrast microscopy. Glass coverslips were examined by epifluorescent and scanning electron microscopy for biofilm formation. The ultrastructure of attached test organisms was examined for the presence of exopolymers using transmission electron microscopy. In pure cultures, attachment of L. monocytogenes to glass coverslips was sparse, while P. fragi accumulated on glass coverslips as a confluent layer of cells. When L. monocytogenes was grown in mixed culture with P. fragi, an exopolymer-producing microorganism, attachment and microcolony formation by L. monocytogenes was enhanced. Results suggest that under flowing conditions the presence of an exopolymer-producing microorganism may be more important than hydrophobicity, surface charge, or flagellar movement in attachment of L. monocytogenes to inert surfaces.

THE ROLE OF BACTERIAL COMMUNITIES ON IN-SITU ARSENIC AND IRON CYCLING IN RIVERBANKS ALONG THE MEGHNA RIVER, BANGLADESH

2020 ◽  
Author(s):  
Kimberly D. Myers ◽  
◽  
Katrina Lee Jewell ◽  
P.S.K. Knappett ◽  
Mehtaz M. Lipsi ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Iron Cycling

scholarly journals Sodium Salicylate Influences the Pseudomonas aeruginosa Biofilm Structure and Susceptibility Towards Silver

2021 ◽  
Vol 22 (3) ◽  
pp. 1060
Author(s):  
Erik Gerner ◽  
Sofia Almqvist ◽  
Peter Thomsen ◽  
Maria Werthén ◽  
Margarita Trobos
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Sodium Salicylate ◽  
Treatment Strategies ◽  
Cell Aggregation ◽  
Wound Fluid ◽  
Global Challenge ◽  
3D Collagen ◽  
Biofilm Development ◽  
Biofilm Structure

Hard-to-heal wounds are typically infected with biofilm-producing microorganisms, such as Pseudomonas aeruginosa, which strongly contribute to delayed healing. Due to the global challenge of antimicrobial resistance, alternative treatment strategies are needed. Here, we investigated whether inhibition of quorum sensing (QS) by sodium salicylate in different P. aeruginosa strains (QS-competent, QS-mutant, and chronic wound strains) influences biofilm formation and tolerance to silver. Biofilm formation was evaluated in simulated serum-containing wound fluid in the presence or absence of sodium salicylate (NaSa). Biofilms were established using a 3D collagen-based biofilm model, collagen coated glass, and the Calgary biofilm device. Furthermore, the susceptibility of 48-h-old biofilms formed by laboratory and clinical strains in the presence or absence of NaSa towards silver was evaluated by assessing cell viability. Biofilms formed in the presence of NaSa were more susceptible to silver and contained reduced levels of virulence factors associated with biofilm development than those formed in the absence of NaSa. Biofilm aggregates formed by the wild-type but not the QS mutant strain, were smaller and less heterogenous in size when grown in cultures with NaSa compared to control. These data suggest that NaSa, via a reduction of cell aggregation in biofilms, allows the antiseptic to become more readily available to cells.

The AMPIX electrochemical cell: a versatile apparatus forin situX-ray scattering and spectroscopic measurements

2012 ◽  
Vol 45 (6) ◽  
pp. 1261-1269 ◽  
Author(s):  
Olaf J. Borkiewicz ◽  
Badri Shyam ◽  
Kamila M. Wiaderek ◽  
Charles Kurtz ◽  
Peter J. Chupas ◽  
...  
Keyword(s):  
Electrochemical Cell ◽  
Function Analysis ◽  
Kinetic Studies ◽  
Spectroscopic Measurements ◽  
Battery Materials ◽  
X Ray ◽  
Complex Processes ◽  
Electrochemical Cycling ◽  
Ray Scattering

This article presents a versatile easy-to-use electrochemical cell suitable forin operando,in situmeasurements of battery materials during electrochemical cycling using a variety of X-ray techniques. Argonne's multi-purposein situX-ray (AMPIX) cell provides reliable electrochemical cycling over extended periods owing to the uniform stack pressure applied by rigid X-ray windows and the formation of a high-fidelity hermetic seal. The suitability of the AMPIX cell for a broad range of synchrotron-based X-ray scattering and spectroscopic measurements has been demonstrated with studies at eight Advanced Photon Source beamlines to date. Compatible techniques include pair distribution function analysis, high-resolution powder diffraction, small-angle scattering and X-ray absorption spectroscopy. These techniques probe a broad range of electronic, structural and morphological features relevant to battery materials. The AMPIX cell enables experiments providing greater insight into the complex processes that occur in operating batteries by allowing the electrochemical reactions to be probed at fine reaction intervals with greater consistency (within the charge–discharge cycle and between different methodologies) with potential for new time-dependent kinetic studies or studies of transient species. Representative X-ray and electrochemical data to demonstrate the functionality of the AMPIX cell are presented.

scholarly journals The Role of Exopolysaccharides in Oral Biofilms

2019 ◽  
Vol 98 (7) ◽  
pp. 739-745 ◽  
Author(s):  
C. Cugini ◽  
M. Shanmugam ◽  
N. Landge ◽  
N. Ramasubbu
Keyword(s):  
Biofilm Formation ◽  
Bacterial Colonization ◽  
Super Resolution ◽  
Extracellular Proteins ◽  
Extracellular Polysaccharides ◽  
Oral Biofilms ◽  
The Matrix ◽  
Oral Microbes ◽  
Biofilm Development

The oral cavity contains a rich consortium of exopolysaccharide-producing microbes. These extracellular polysaccharides comprise a major component of the oral biofilm. Together with extracellular proteins, DNA, and lipids, they form the biofilm matrix, which contributes to bacterial colonization, biofilm formation and maintenance, and pathogenesis. While a number of oral microbes have been studied in detail with regard to biofilm formation and pathogenesis, the exopolysaccharides have been well characterized for only select organisms, namely Streptococcus mutans and Aggregatibacter actinomycetemcomitans. Studies on the exopolysaccharides of other oral organisms, however, are in their infancy. In this review, we present the current research on exopolysaccharides of oral microbes regarding their biosynthesis, regulation, contributions to biofilm formation and stability of the matrix, and immune evasion. In addition, insight into the role of exopolysaccharides in biofilms is highlighted through the evaluation of emerging techniques such as pH probing of biofilm colonies, solid-state nuclear magnetic resonance for macromolecular interactions within biofilms, and super-resolution microscopy analysis of biofilm development. Finally, exopolysaccharide as a potential nutrient source for species within a biofilm is discussed.

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