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Acanthamoeba
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
In addition, Acanthamoeba may harbor various microbial endosymbionts (e.g., Candidatus Caedibacter acanthamoebae, Candidatus Odyssella thessalonicensis, Candidatus Paracaedibacter acanthamoebae, Candidatus Paracaedibacter symbiosus, Comamonas acidovorans, Legionella pneumophila, Pseudomonas aeruginosa, mimivirus, megavirus, and pandoravirus). Further, a large number of other bacterial species (e.g., Aeromonas, Bacillus cereus, Bartonella, Burkholderia, Campylobacter jejuni, Chlamydia pnuemoniae, Coxiella burnetii, Cytophaga, E. coli O157:H7, Flavobacterium, Francisella tularensis, Helicobacter pylori, Listeria, Mycobacterium, Pasteurella multocida, Prevotella intermedia, Porphyromonas gingivalis, Rickettsia, Salmonella Typhimurium, Shigella, Simkania negevensis, Staphylococcus aureus, Vibrio, and Waddlia chondrophila) have been shown to survive and multiply within Acanthamoeba. This highlights the potential role of Acanthamoeba in serving as bacterial reservoirs for human infections [2,12].
Introduction — History and Importance of Acinetobacter spp., Role in Infections, Treatment and Cost Implications
Published in E. Bergogne-Bénézin, M.L. Joly-Guillou, K.J. Towner, Acinetobacter, 2020
E. Bergogne-Bérézin, M.-L. Joly-Guillou, K.J. Towner
Before a particular bacterial species or genus can be implicated in infections and recognised as potentially pathogenic in man, it must be clearly defined, classified and identified. The genus Acinetobacter has undergone extensive and confusing taxonomic changes over many years, and these organisms have been classified previously in various genera (see Appendix I), the most common being designated Bacterium anitratum (Schaub et al., 1948), Herellea vaginicola and Mima polymorpha(Debord, 1939), Achromobacter, Alcaligenes, Neisseria, Micrococcus calcoaceticus, Diplococcus, ‘B5W’ and Cytophaga (Juni, 1972). The genus Acinetobacter, as conceived originally by Brisou and Prevot (1954), included oxidase-positive (Moraxella) and oxidase-negative strains (Piechaud, 1961; Bovre and Henriksen, 1976). In 1961, in the Annales de I’lnstitut Pasteur, Piechaud described strictly aerobic, oxidase-negative, Gram-negative coccobacilli, that he considered should be classified as either Moraxella glucidolytica (including ‘B5W’ and Bacterium anitratum),for strains acidifying glucose, or Moraxella Iwoffii. Both species were penicillin resistant, and the identification of strains was based on phenotypic characters (cultural and metabolic) and morphology, which was described in precise detail, including cell division stages revealed by the Piekarski-Robinow dyeing technique. Piéchaud stated at the end of the article "Rien ne justifie l’inclusion de M. Iwoffii, de M. glucidolyticaet de leurs variétés dans un genre Acinetobacter (Brisou, 1957), groupe hétérogène (dont la plupart des espèces sont decrites comme anaerobies facultatives) tels Acinetobacter stenohalis, butyri, eurydice, delmarvae, marshalli, metalcaligenes…."*
High-throughput method development for in-situ quantification of aquatic phototrophic biofilms
Published in Biofouling, 2022
Maria Papadatou, Mollie Knight, Maria Salta
The utilisation of plate readers has been successfully adapted for laboratory assessment of bacterial (e.g. Stafslien et al. 2006, 2007) and microalgal (e.g. Cassé et al. 2007a, 2007b) biofilm attachment. Stafslien et al. (2006) developed a fabricated temperature-controlled, circulated water bath incubator tank. The novel high-throughput method based on crystal violet staining and plate reader absorbance measurements, enabled the assessment of marine bacterial biofilm growth. Effectiveness and versatility of the bioassay was then tested for assessment of bacterial biofilm retention (Pseudoalteromonas atlantica, Cobetia marina, Halomonas pacifica, Cytophaga lytica) on antifouling surfaces, and demonstrated to be successful in the primary screening of antifouling coatings for identification of promising candidates (Stafslien et al. 2007). Cassé et al. (2007a) constructed a water-controlled spinjet apparatus with variable pressure (application of hydrodynamic forces) to facilitate biomass quantification of Navicula perminuta diatom and Ulva linza macroalga sporelings using fluorescence plate reader, and cell adhesion strength using epifluorescence microscope. The laboratory bioassay facilitated the screening of the adhesion strength of algae that allowed evaluation of novel fouling-release coatings. Cassé et al. (2007b) established an algorithm to quantify the algal (Ulva linza zoospores) biomass coverage from coatings using digital image analysis for visual assessment, which proved to be reproducible semi-high-throughput for characterising coatings performance.
Characterization of oral bacteria in the tongue coating of patients with halitosis using 16S rRNA analysis
Published in Acta Odontologica Scandinavica, 2020
Akiko Oshiro, Takashi Zaitsu, Masayuki Ueno, Yoko Kawaguchi
Analysis of the bacterial composition at the phylum level revealed that Actinobacteria, Bacteroidetes, Firmicutes, Fusobacteria, and Proteobacteria, inhabited the tongue coating in all subjects regardless of the halitosis status. The Actinobacteria phylum includes 15 genera, and most of them are found in dental caries and denture plaque [29,30]. The Bacteroidetes phylum is part of Cytophaga-Flavobacterium-Bacteroidetes (CFB) and is a major constituent of the intestinal flora, possibly originating from the oral cavity [30]. The Firmicutes phylum includes nearly 200 genera, and Streptococcus is one of them [29–32]. Bacteria from the Fusobacteria phylum are often found in dental plaque, and they represent periodontopathic bacteria [30,32,33]. The Proteobacteria phylum includes many classes and a wide variety of pathogenic intestinal bacteria. These bacterial phyla are commonly identified in the oral cavity and are detected in most people.
Characterization and removal of biofouling from reverse osmosis membranes (ROMs) from a desalination plant in Northern Chile, using Alteromonas sp. Ni1-LEM supernatant
Published in Biofouling, 2020
Hernán Vera-Villalobos, Vilma Pérez, Francisco Contreras, Valezka Alcayaga, Vladimir Avalos, Carlos Riquelme, Fernando Silva-Aciares
Marine bacteria spend extended periods in the stationary phase and produce active secondary metabolites (Silva-Aciares and Riquelme 2008). Lovejoy et al. (1998) suggested that microorganisms with molecules that inhibit algal growth act through direct and indirect mechanisms. An example of a direct mechanism is the effective lysis of microalgal cultures by Cytophaga sp. strain J18/M01, whilst when microalgae are treated with extracellular compounds of Cytophaga sp. an effect was absent (Imai et al. 1993). In contrast, an indirect mechanism corresponds to the inhibition of microalgal growth or attachment by secreted molecules. Lovejoy et al. (1998) evaluated the effect of two isolated Pseudoalteromonas strains from Huon Estuary, Tasmania, Australia on growth rates of Gymnodinium catenatum, Chattonella marina, and Heterosigma akashiwo. The presence of bacterial compounds of high molecular weight inhibited the growth rates in the dinoflagellates studied. Alteromonas sp. Ni1-LEM, in its prolonged stationary growth phase, produces metabolites that actively inhibit fouling organisms (Infante et al. 2018). The antialgal compound secreted by Alteromonas sp. Ni1-LEM is water-soluble, heat-sensitive, polar, and has a molecular size of 3,500 Da (Silva-Aciares and Riquelme 2008). Previous research has shown that Alteromonas sp. Ni1-LEM and its extracellular products inhibit the settlement of a wide range of marine biofouling organisms including the mussel Semimytilus algosus (Ayala et al. 2006), tunicate larvae of Ciona intestinalis, Pyura praeputialis (Zapata et al. 2007), zoospores of Ulva lactuca and eight species of common benthic diatoms of the marine intertidal zone of Chile (Silva-Aciares and Riquelme 2008). Nevertheless, the effects of the secreted products of Alteromonas sp. Ni1-LEM on microalgae from ROMs have not been reported. In this study, the antifouling properties of the Alteromonas sp. Ni1-LEM supernatant in the adherence of the seven diatoms isolated from ROMs were evaluated. The results revealed that 100 µg ml−1 of the Alteromonas sp. Ni1-LEM supernatant increased cell detachment by approximately 50% in the microalgae isolated from the ROMs (Table 2). Moreover, this concentration was previously tested against Nitzschia ovalis (Infante et al. 2018), used as a positive control in this study, showing a 54% decrease in cell adherence of this microalga. Thus, the action of the supernatant of Alteromonas sp. Ni1-LEM is not species-specific and it can be successfully used against a broad spectrum of microalgal biofilms, adding to its potential as a cleaning agent against complex biofilms in RO plants (Chiellini et al. 2012; Belila et al. 2016).