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Arnett, C. M., A. M. Beckman, M. D. Ginsberg, and V. F. Hock. "Influence of bacterial biofilms on Bacillus globigii spore viability in model chlorinated water distribution systems." Water Supply 10, no. 3 (2010): 277–85. http://dx.doi.org/10.2166/ws.2010.036.
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Viability of Bacillus globigii spores in chlorinated polyvinyl chloride (PVC) pipe loop systems were examined under oligotrophic conditions. Three 2.5 cm × 10 m pipe loops having poised free chlorine concentrations of 0.0, 0.5, and 1.0 mg/L were seeded with 3.0 × 108B. globigii spores each and viability was assessed over a 21 day period in both the recirculating waters and within the biofilms associated with pipe wall surfaces. After 10 min of exposure, viable spores were found to be associated within the pipe biofilms. In the untreated pipe loop spore counts remained statistically consistent in both the bulk water and biofilm until 1.0 mg/L free chlorine was introduced, then spores were completely inactivated in less than seven days. Spores within the pipe loop poised at 0.5 mg/L free chlorine showed a 7.6-log10 inactivation in the bulk water phase, but only a 2.7-log10 inactivation was observed within the biofilm after 14 days of treatment. Complete inactivation was observed in the 1.0 mg/L free chlorine system in both the biofilm and the bulk water phase in less than 10 min. These data demonstrated that B. globigii spores were readily incorporated into PVC pipe biofilms, which decreased spore inactivation nearly five orders of magnitude under moderate free chlorine concentrations.
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Wijman, Janneke G. E., Patrick P. L. A. de Leeuw, Roy Moezelaar, Marcel H. Zwietering, and Tjakko Abee. "Air-Liquid Interface Biofilms of Bacillus cereus: Formation, Sporulation, and Dispersion." Applied and Environmental Microbiology 73, no. 5 (2007): 1481–88. http://dx.doi.org/10.1128/aem.01781-06.
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ABSTRACT Biofilm formation by Bacillus cereus was assessed using 56 strains of B. cereus, including the two sequenced strains, ATCC 14579 and ATCC 10987. Biofilm production in microtiter plates was found to be strongly dependent on incubation time, temperature, and medium, as well as the strain used, with some strains showing biofilm formation within 24 h and subsequent dispersion within the next 24 h. A selection of strains was used for quantitative analysis of biofilm formation on stainless steel coupons. Thick biofilms of B. cereus developed at the air-liquid interface, while the amount of biofilm formed was much lower in submerged systems. This suggests that B. cereus biofilms may develop particularly in industrial storage and piping systems that are partly filled during operation or where residual liquid has remained after a production cycle. Moreover, depending on the strain and culture conditions, spores constituted up to 90% of the total biofilm counts. This indicates that B. cereus biofilms can act as a nidus for spore formation and subsequently can release their spores into food production environments.
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LINDSAY, D., V. S. BRÖZEL, and A. von HOLY. "Spore Formation in Bacillus subtilis Biofilms." Journal of Food Protection 68, no. 4 (2005): 860–65. http://dx.doi.org/10.4315/0362-028x-68.4.860.
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Spore formation by a Bacillus strain (Bacillus subtilis SpoIVFB-GFP) engineered with a green fluorescent protein (GFP) fused to a polytopic membrane protein (SpoIVF) that fluoresces during sporulation was observed. Biofilms of B. subtilis SpoIVFB-GFP containing ca. 8 log CFU/ml vegetative cells and spores below the lower detection limit (i.e., <1 log CFU/ml) were allowed to develop on glass wool (37°C). These biofilms were subsequently exposed to nutrient limitation to stimulate spore formation, which was monitored for fluorescence by confocal scanning laser microscopy. Sporulation in corresponding planktonic cells was also monitored for comparative purposes. Planktonic B. subtilis SpoIVFB-GFP cells began fluorescing after 5 h, while B. subtilis SpoIVFB-GFP biofilm cells began fluorescing after 30 h. Results suggested that an existing biofilm of vegetative B. subtilis cells may be stimulated to form spores when exposed to conditions of nutrient limitation. From a practical point of view, it may be suggested that a window of time does exist before sporulation occurs in attached Bacillus biofilms highlighting the need for shorter operating runs between cleaning and sanitation of food-processing equipment surfaces.
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Hu, Wen Si, Dong U. Woo, Yang Jae Kang, and Ok Kyung Koo. "Biofilm and Spore Formation of Clostridium perfringens and Its Resistance to Disinfectant and Oxidative Stress." Antibiotics 10, no. 4 (2021): 396. http://dx.doi.org/10.3390/antibiotics10040396.
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Clostridium perfringens is a major human pathogen that causes gastroenteritis via enterotoxin production and has the ability to form spores and biofilms for environmental persistence and disease transmission. This study aimed to compare the disinfectant and environmental resistance properties of C. perfringens vegetative cells and spores in planktonic and sessile conditions, and to examine the nucleotide polymorphisms and transcription under sessile conditions in C. perfringens strains isolated from meat. The sporulation rate of sessile C. perfringens TYJAM-D-66 (cpe+) was approximately 19% at day 5, while those of CMM-C-80 (cpe−) and SDE-B-202 (cpe+) were only 0.26% and 0.67%, respectively, at day 7. When exposed to aerobic conditions for 36 h, TYJAM-D-66, CMM-C-80, and SDE-B-202 vegetative cells showed 1.70 log, 5.36 log, and 5.67 log reductions, respectively. After treatment with sodium hypochlorite, the survival rates of TYJAM-D-66 vegetative cells (53.6%) and spores (82.3%) in biofilms were higher than those of planktonic cells (9.23%). Biofilm- and spore-related genes showed different expression within TYJAM-D-66 (–4.66~113.5), CMM-C-80 (–3.02~2.49), and SDE-B-202 (–5.07~2.73). Our results indicate the resistance of sessile cells and spores of C. perfringens upon exposure to stress conditions after biofilm formation.
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LINDSAY, D., V. S. BRÖZEL, and A. VON HOLY. "Biofilm-Spore Response in Bacillus cereus and Bacillus subtilis during Nutrient Limitation." Journal of Food Protection 69, no. 5 (2006): 1168–72. http://dx.doi.org/10.4315/0362-028x-69.5.1168.
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This study aimed to trace the dynamics of biofilm formation by vegetative cells and endospores of Bacillus cereus DL5 and Bacillus subtilis 168. Counts of B. cereus DL5 and B. subtilis 168 vegetative cells and spores either attached to glass wool or, correspondingly, planktonic cells were determined by standard plate-counting methods. Results from this study highlighted the biofilm-forming potential of both spores and vegetative cells of two different Bacillus species. It was shown that once Bacillus spores had attached to a surface, the spores germinated under favorable (B. cereus DL5) and even unfavorable (B. subtilis 168) nutrient conditions, resulting in biofilms containing both spores and vegetative populations. Furthermore, it was suggested that vegetative B. cereus DL5 cells exhibited a low propensity for spore formation in attached and planktonic growth forms in nutrient-limited growth medium. By contrast, vegetative B. subtilis 168 cells readily formed spores in planktonic and attached microcosms when exposed to nutrient-limited growth conditions. Sporulation in attached Bacillus populations is an important practical consideration for many food industries, such as dairy processing, where bacilli are routinely isolated from populations attached to processing-equipment surfaces.
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Hupka, Megan, Raj Kedia, Rylee Schauer, et al. "Morphology of Penicillium rubens Biofilms Formed in Space." Life 13, no. 4 (2023): 1001. http://dx.doi.org/10.3390/life13041001.
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Fungi biofilms have been found growing on spacecraft surfaces such as windows, piping, cables, etc. The contamination of these surfaces with fungi, although undesirable, is highly difficult to avoid. While several biofilm forming species, including Penicillium rubens, have been identified in spacecraft, the effect of microgravity on fungal biofilm formation is unknown. This study sent seven material surfaces (Stainless Steel 316, Aluminum Alloy, Titanium Alloy, Carbon Fiber, Quartz, Silicone, and Nanograss) inoculated with spores of P. rubens to the International Space Station and allowed biofilms to form for 10, 15, and 20 days to understand the effects of microgravity on biofilm morphology and growth. In general, microgravity did not induce changes in the shape of biofilms, nor did it affect growth in terms of biomass, thickness, and surface area coverage. However, microgravity increased or decreased biofilm formation in some cases, and this was incubation-time- and material-dependent. Nanograss was the material with significantly less biofilm formation, both in microgravity and on Earth, and it could potentially be interfering with hyphal adhesion and/or spore germination. Additionally, a decrease in biofilm formation at 20 days, potentially due to nutrient depletion, was seen in some space and Earth samples and was material-dependent.
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Gong, Jinglei, Die Hu, Jinzhi He, Ling Zou, Zhu Chen, and Mingyun Li. "Effect of LongZhang Gargle on Dual-Species Biofilm of Candida albicans and Streptococcus mutans." BioMed Research International 2021 (March 22, 2021): 1–10. http://dx.doi.org/10.1155/2021/6654793.
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Bioactive natural products have become a hot spot for oral disease treatments. At the present study, LongZhang Gargle was investigated for its effects on single-species biofilms of Candida albicans and dual-species biofilms of Candida albicans and Streptococcus mutans. Two different models of single and dual-species biofilms were grown in YNBB medium under appropriate conditions. Biofilm biomass, biofilm architecture, and cell activity in biofilms were assessed using Crystal Violet Staining, MTT, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Significant reductions of biofilm biomass and fungus activity were obtained when treated with LongZhang Gargle at 2% ( P < 0.05 ), 4% ( P < 0.05 ), and 8% ( P < 0.05 ) in single-species biofilms of C. albicans, and at 4% ( P < 0.05 ) and 8% ( P < 0.05 ) in double-species biofilms. Suppression of density, thickness, and the proportion of hyphae and fungal spores were obtained under SEM and CLSM. In conclusion, LongZhang Gargle affects single and dual-species biofilms by inhibiting biofilm biomass, cell activity, and formation of hyphae, but it does not affect the production of Extracellular polysaccharides (EPS). We speculate that LongZhang Gargle would be a promising natural drug, which can be used in treatment against C. albicans and S. mutans in oral diseases.
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Pizarro-Guajardo, Marjorie, Paulina Calderón-Romero, and Daniel Paredes-Sabja. "Ultrastructure Variability of the Exosporium Layer of Clostridium difficile Spores from Sporulating Cultures and Biofilms." Applied and Environmental Microbiology 82, no. 19 (2016): 5892–98. http://dx.doi.org/10.1128/aem.01463-16.
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ABSTRACTThe anaerobic sporeformerClostridium difficileis the leading cause of nosocomial antibiotic-associated diarrhea in developed and developing countries. The metabolically dormant spore form is considered the morphotype responsible for transmission, infection, and persistence, and the outermost exosporium layer is likely to play a major role in spore-host interactions during recurrent infections, contributing to the persistence of the spore in the host. A recent study (M. Pizarro-Guajardo, P. Calderón-Romero, P. Castro-Córdova, P. Mora-Uribe, and D. Paredes-Sabja, Appl Environ Microbiol 82:2202–2209, 2016,http://dx.doi.org/10.1128/AEM.03410-15) demonstrated by transmission electron microscopy the presence of two ultrastructural morphotypes of the exosporium layer in spores formed from the same sporulating culture. However, whether these distinct morphotypes appeared due to purification techniques and whether they appeared during biofilm development remain unclear. In this communication, we demonstrate through transmission electron microscopy that these two exosporium morphotypes are formed under sporulation conditions and are also present in spores formed during biofilm development. In summary, this work provides definitive evidence that in a population of sporulating cells, spores with a thick outermost exosporium layer and spores with a thin outermost exosporium layer are formed.IMPORTANCEClostridium difficilespores are recognized as the morphotype of persistence and transmission ofC. difficileinfections. Spores ofC. difficileare intrinsically resistant to all known antibiotic therapies. Development of spore-based removal strategies requires a detailed knowledge of the spore surface for proper antigen selection. In this context, in this work we provide definitive evidence that two types of spores, those with a thick outermost exosporium layer and those with a thin outermost exosporium layer, are formed in the sameC. difficilesporulating culture or during biofilm development.
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ANJOS, MÁRCIA MARIA dos, SUELEN PEREIRA RUIZ, CELSO VATARU NAKAMURA, and BENÍCIO ALVES de ABREU FILHO. "Resistance of Alicyclobacillus acidoterrestris Spores and Biofilm to Industrial Sanitizers." Journal of Food Protection 76, no. 8 (2013): 1408–13. http://dx.doi.org/10.4315/0362-028x.jfp-13-020.
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This study evaluated the adhesion and biofilm formation of Alicyclobacillus acidoterrestris on industrial orange juice processing equipment and the bactericidal efficacy of peracetic acid, sodium hypochlorite, and quaternary ammonia after biofilm formation. The efficacy of these sanitizers against the spores of this microorganism was also evaluated. Stainless steel and nylon surfaces exhibited higher cell adhesion levels than did polyvinyl chloride surfaces. Peracetic acid was the most effective in removing biofilms from all surfaces (P &lt; 0.05) and also reduced bacterial counts by 3 log CFU/cm2 on the surface of polyvinyl chloride, but the other sanitizers also reduced the bacterial counts by 2 log CFU/cm2. Quaternary ammonia exhibited the optimal minimum sporicidal concentration, preventing spore germination after only 15 s of contact at a concentration of 82 ppm. The flow cytometry results indicated that the spores and cells had low incidences of plasma membrane lysis after treatment with sanitizer, suggesting that lysis is not the principal mode of action for these sanitizers on A. acidoterrestris.
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Gerwig, Jan, Taryn B. Kiley, Katrin Gunka, Nicola Stanley-Wall, and Jörg Stülke. "The protein tyrosine kinases EpsB and PtkA differentially affect biofilm formation in Bacillus subtilis." Microbiology 160, no. 4 (2014): 682–91. http://dx.doi.org/10.1099/mic.0.074971-0.
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The Gram-positive soil bacterium Bacillus subtilis is able to choose between motile and sessile lifestyles. The sessile way of life, also referred to as biofilm, depends on the formation of an extracellular polysaccharide matrix and some extracellular proteins. Moreover, a significant proportion of cells in a biofilm form spores. The first two genes of the 15-gene operon for extracellular polysaccharide synthesis, epsA and epsB, encode a putative transmembrane modulator protein and a putative protein tyrosine kinase, respectively, with similarity to the TkmA/PtkA modulator/kinase couple. Here we show that the putative kinase EpsB is required for the formation of structured biofilms. However, an epsB mutant is still able to form biofilms. As shown previously, a ptkA mutant is also partially defective in biofilm formation, but this defect is related to spore formation in the biofilm. The absence of both kinases resulted in a complete loss of biofilm formation. Thus, EpsB and PtkA fulfil complementary functions in biofilm formation. The activity of bacterial protein tyrosine kinases depends on their interaction with modulator proteins. Our results demonstrate the specific interaction between the putative kinase EpsB and its modulator protein EpsA and suggest that EpsB activity is stimulated by its modulator EpsA.
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Singh, Rachna, M. R. Shivaprakash, and Arunaloke Chakrabarti. "Biofilm formation by zygomycetes: quantification, structure and matrix composition." Microbiology 157, no. 9 (2011): 2611–18. http://dx.doi.org/10.1099/mic.0.048504-0.
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Most studies on fungal biofilms have focused on Candida in yeasts and Aspergillus in mycelial fungi. To the authors’ knowledge, biofilm formation by zygomycetes has not been reported previously. In this study, the biofilm-forming capacity of Rhizopus oryzae, Lichtheimia corymbifera, Rhizomucor pusillus and Apophysomyces elegans was evaluated. At appropriate seeding spore densities, Rhp . oryzae (105 c.f.u. ml−1), L. corymbifera (104 c.f.u. ml−1) and Rhm. pusillus (104 c.f.u. ml−1) produced highly intertwined, adherent structures on flat-bottomed polystyrene microtitre plates after 24 h at 37 °C. The adhered fungal hyphae were encased in an extracellular matrix, as confirmed by phase-contrast and confocal microscopy. The thickness of Rhp. oryzae, L. corymbifera and Rhm. pusillus biofilms was 109.67±10.02, 242±23.07 and 197±9.0 µm (mean±sd), respectively. Biochemical characterization of the biofilm matrix indicated the presence of glucosamine, constituting 74.54–82.22 % of its dry weight, N-acetylglucosamine, glucose and proteins. Adherence and biofilm formation were not observed in A. elegans. Although A. elegans spores germinated at all three seeding densities tested (1×107, 1×106 and 1×105 c.f.u. ml−1), no significant difference was observed (P>0.05) between the A 490 of wells inoculated with A. elegans and the cut-off A 490 for biofilm detection. This study highlights the potential for biofilm formation by at least three medically important species of zygomycetes.
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Veening, Jan-Willem, Oscar P. Kuipers, Stanley Brul, Klaas J. Hellingwerf, and Remco Kort. "Effects of Phosphorelay Perturbations on Architecture, Sporulation, and Spore Resistance in Biofilms of Bacillus subtilis." Journal of Bacteriology 188, no. 8 (2006): 3099–109. http://dx.doi.org/10.1128/jb.188.8.3099-3109.2006.
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ABSTRACT The spore-forming bacterium Bacillus subtilis is able to form highly organized multicellular communities called biofilms. This coordinated bacterial behavior is often lost in domesticated or laboratory strains as a result of planktonic growth in rich media for many generations. However, we show here that the laboratory strain B. subtilis 168 is still capable of forming spatially organized multicellular communities on minimal medium agar plates, exemplified by colonies with vein-like structures formed by elevated bundles of cells. In line with the current model for biofilm formation, we demonstrate that overproduction of the phosphorelay components KinA and Spo0A stimulates bundle formation, while overproduction of the transition state regulators AbrB and SinR leads to repression of formation of elevated bundles. Time-lapse fluorescence microscopy studies of B. subtilis green fluorescent protein reporter strains show that bundles are preferential sites for spore formation and that flat structures surrounding the bundles contain vegetative cells. The elevated bundle structures are formed prior to sporulation, in agreement with a genetic developmental program in which these processes are sequentially activated. Perturbations of the phosphorelay by disruption and overexpression of genes that lead to an increased tendency to sporulate result in the segregation of sporulation mutations and decreased heat resistance of spores in biofilms. These results stress the importance of a balanced control of the phosphorelay for biofilm and spore development.
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Zhao, Yu, Martien P. M. Caspers, Karin I. Metselaar, et al. "Abiotic and Microbiotic Factors Controlling Biofilm Formation by Thermophilic Sporeformers." Applied and Environmental Microbiology 79, no. 18 (2013): 5652–60. http://dx.doi.org/10.1128/aem.00949-13.
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ABSTRACTOne of the major concerns in the production of dairy concentrates is the risk of contamination by heat-resistant spores from thermophilic bacteria. In order to acquire more insight in the composition of microbial communities occurring in the dairy concentrate industry, a bar-coded 16S amplicon sequencing analysis was carried out on milk, final products, and fouling samples taken from dairy concentrate production lines. The analysis of these samples revealed the presence of DNA from a broad range of bacterial taxa, including a majority of mesophiles and a minority of (thermophilic) spore-forming bacteria. Enrichments of fouling samples at 55°C showed the accumulation of predominantlyBrevibacillusandBacillus, whereas enrichments at 65°C led to the accumulation ofAnoxybacillusandGeobacillusspecies. Bacterial population analysis of biofilms grown using fouling samples as an inoculum indicated that bothAnoxybacillusandGeobacilluspreferentially form biofilms on surfaces at air-liquid interfaces rather than on submerged surfaces. Three of the most potent biofilm-forming strains isolated from the dairy factory industrial samples, includingGeobacillus thermoglucosidans,Geobacillus stearothermophilus, andAnoxybacillus flavithermus, have been characterized in detail with respect to their growth conditions and spore resistance. Strikingly,Geobacillus thermoglucosidans, which forms the most thermostable spores of these three species, is not able to grow in dairy intermediates as a pure culture but appears to be dependent for growth on other spoilage organisms present, probably as a result of their proteolytic activity. These results underscore the importance of abiotic and microbiotic factors in niche colonization in dairy factories, where the presence of thermophilic sporeformers can affect the quality of end products.
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Burgess, S. A., J. D. Brooks, J. Rakonjac, K. M. Walker, and S. H. Flint. "The formation of spores in biofilms ofAnoxybacillus flavithermus." Journal of Applied Microbiology 107, no. 3 (2009): 1012–18. http://dx.doi.org/10.1111/j.1365-2672.2009.04282.x.
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KRESKE, AUDREY C., JEE-HOON RYU, CHARLES A. PETTIGREW, and LARRY R. BEUCHAT. "Lethality of Chlorine, Chlorine Dioxide, and a Commercial Produce Sanitizer to Bacillus cereus and Pseudomonas in a Liquid Detergent, on Stainless Steel, and in Biofilm." Journal of Food Protection 69, no. 11 (2006): 2621–34. http://dx.doi.org/10.4315/0362-028x-69.11.2621.
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Many factors that are not fully understood may influence the effectiveness of sanitizer treatments for eliminating pathogens and spoilage microorganisms in food or detergent residues or in biofilms on food contact surfaces. This study was done to determine the sensitivities of Pseudomonas cells and Bacillus cereus cells and spores suspended in a liquid dishwashing detergent and inoculated onto the surface of stainless steel to treatment with chlorine, chlorine dioxide, and a commercial produce sanitizer (Fit). Cells and spores were incubated in a liquid dishwashing detergent for 16 to 18 h before treatment with sanitizers. At 50 μg/ml, chlorine dioxide killed a significantly higher number of Pseudomonas cells (3.82 log CFU/ml) than did chlorine (a reduction of 1.34 log CFU/ml). Stainless steel coupons were spot inoculated with Pseudomonas cells and B. cereus cells and spores, with water and 5% horse serum as carriers. Chlorine was more effective than chlorine dioxide in killing cells and spores of B. cereus suspended in horse serum. B. cereus biofilm on stainless steel coupons that were treated with chlorine dioxide or chlorine at 200 μg/ml had total population reductions (vegetative cells plus spores) of ≥4.42 log CFU per coupon; the number of spores was reduced by ≥3.80 log CFU per coupon. Fit (0.5%) was ineffective for killing spot-inoculated B. cereus and B. cereus in biofilm, but treatment with mixtures of Fit and chlorine dioxide caused greater reductions than did treatment with chlorine dioxide alone. In contrast, when chlorine was combined with Fit, the lethality of chlorine was completely lost. This study provides information on the survival and sanitizer sensitivity of Pseudomonas and B. cereus in a liquid dishwashing detergent, on the surface of stainless steel, and in a biofilm. This information will be useful for developing more effective strategies for cleaning and sanitizing contact surfaces in food preparation and processing environments.
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KİLİC, TUGBA. "Biofilm-Forming Ability and Effect of Sanitation Agents on Biofilm-Control of Thermophile Geobacillus sp. D413 and Geobacillus toebii E134." Polish Journal of Microbiology 69, no. 4 (2020): 411–19. http://dx.doi.org/10.33073/pjm-2020-042.
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Geobacillus sp. D413 and Geobacillus toebii E134 are aerobic, non-pathogenic, endospore-forming, obligately thermophilic bacilli. Gram-positive thermophilic bacilli can produce heat-resistant spores. The bacteria are indicator organisms for assessing the manufacturing process’s hygiene and are capable of forming biofilms on surfaces used in industrial sectors. The present study aimed to determine the biofilm-forming properties of Geobacillus isolates and how to eliminate this formation with sanitation agents. According to the results, extracellular DNA (eDNA) was interestingly not affected by the DNase I, RNase A, and proteinase K. However, the genomic DNA (gDNA) was degraded by only DNase I. It seemed that the eDNA had resistance to DNase I when purified. It is considered that the enzymes could not reach the target eDNA. Moreover, the eDNA resistance may result from the conserved folded structure of eDNA after purification. Another assumption is that the eDNA might be protected by other extracellular polymeric substances (EPS) and/or extracellular membrane vesicles (EVs) structures. On the contrary, DNase I reduced unpurified eDNA (mature biofilms). Biofilm formation on surfaces used in industrial areas was investigated in this work: the D413 and E134 isolates adhered to all surfaces. Various sanitation agents could control biofilms of Geobacillus isolates. The best results were provided by nisin for D413 (80%) and α-amylase for E134 (98%). This paper suggests that sanitation agents could be a solution to control biofilm structures of thermophilic bacilli.
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Tam, Nguyen K. M., Nguyen Q. Uyen, Huynh A. Hong, et al. "The Intestinal Life Cycle of Bacillus subtilis and Close Relatives." Journal of Bacteriology 188, no. 7 (2006): 2692–700. http://dx.doi.org/10.1128/jb.188.7.2692-2700.2006.
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ABSTRACT Bacillus subtilis is considered a soil organism for which endospore formation provides a means to ensure long-term survival in the environment. We have addressed here the question of what happens to a spore when ingested. Spores displaying on their surface a heterologous antigen, tetanus toxin fragment C (TTFC), were shown to generate anti-TTFC responses not to the antigen contained in the primary oral inoculum but to those displayed on spores that had germinated and then resporulated. We then used reverse transcription-PCR to determine expression of vegetative genes and sporulation-specific genes in the mouse gut following oral dosing with spores. Significant levels of germination and sporulation were documented. Using natural isolates of B. subtilis that could form biofilms, we showed that these strains could persist in the mouse gut for significantly longer than the laboratory strain. Moreover, these isolates could grow and sporulate anaerobically and exhibited a novel phenomenon of being able to form spores in almost half the time required for the laboratory isolate. This suggests that spores are not transient passengers of the gastrointestinal tract but have adapted to carry out their entire life cycle within this environment. This is the first report showing an intestinal life cycle of B. subtilis and suggests that other Bacillus species could also be members of the gut microflora.
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Huang, Yiying, Steve H. Flint, and Jon S. Palmer. "Bacillus cereus spores and toxins – The potential role of biofilms." Food Microbiology 90 (September 2020): 103493. http://dx.doi.org/10.1016/j.fm.2020.103493.
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K, Capriotti, Pelletier J, Barone S, and Capriotti J. "Efficacy of Dilute Povidone-Iodine against Multi- Drug Resistant Bacterial Biofilms, Fungal Biofilms and Fungal Spores." Journal of Clinical Research in Dermatology 5, no. 1 (2018): 1–5. http://dx.doi.org/10.15226/2378-1726/5/1/00174.
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Dobretsov, Sergey, and Daniel Rittschof. "Love at First Taste: Induction of Larval Settlement by Marine Microbes." International Journal of Molecular Sciences 21, no. 3 (2020): 731. http://dx.doi.org/10.3390/ijms21030731.
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Marine biofilms are composed of many species of bacteria, unicellular algae, and protozoa. Biofilms can induce, inhibit, or have no effect on settlement of larvae and spores of algae. In this review, we focus on induction of larval settlement by marine bacteria and unicellular eukaryotes and review publications from 2010 to September 2019. This review provides insights from meta-analysis on what is known about the effect of marine biofilms on larval settlement. Of great interest is the impact of different components of marine biofilms, such as bacteria and diatoms, extracellular polymeric substances, quorum sensing signals, unique inductive compounds, exoenzymes, and structural protein degradation products on larval settlement and metamorphosis. Molecular aspects of larval settlement and impact of climate change are reviewed and, finally, potential areas of future investigations are provided.
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Wang, Kai-Ling, Zheng-Rong Dou, Gao-Fen Gong, Hai-Feng Li, Bei Jiang, and Ying Xu. "Anti-Larval and Anti-Algal Natural Products from Marine Microorganisms as Sources of Anti-Biofilm Agents." Marine Drugs 20, no. 2 (2022): 90. http://dx.doi.org/10.3390/md20020090.
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Bacteria growing inside biofilms are more resistant to hostile environments, conventional antibiotics, and mechanical stresses than their planktonic counterparts. It is estimated that more than 80% of microbial infections in human patients are biofilm-based, and biofouling induced by the biofilms of some bacteria causes serious ecological and economic problems throughout the world. Therefore, exploring highly effective anti-biofilm compounds has become an urgent demand for the medical and marine industries. Marine microorganisms, a well-documented and prolific source of natural products, provide an array of structurally distinct secondary metabolites with diverse biological activities. However, up to date, only a handful of anti-biofilm natural products derived from marine microorganisms have been reported. Meanwhile, it is worth noting that some promising antifouling (AF) compounds from marine microbes, particularly those that inhibit settlement of fouling invertebrate larvae and algal spores, can be considered as potential anti-biofilm agents owing to the well-known knowledge of the correlations between biofilm formation and the biofouling process of fouling organisms. In this review, a total of 112 anti-biofilm, anti-larval, and anti-algal natural products from marine microbes and 26 of their synthetic analogues are highlighted from 2000 to 2021. These compounds are introduced based on their microbial origins, and then categorized into the following different structural groups: fatty acids, butenolides, terpenoids, steroids, phenols, phenyl ethers, polyketides, alkaloids, flavonoids, amines, nucleosides, and peptides. The preliminary structure-activity relationships (SAR) of some important compounds are also briefly discussed. Finally, current challenges and future research perspectives are proposed based on opinions from many previous reviews.
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Permpoonpattana, P., H. A. Hong, R. Khaneja, and S. M. Cutting. "Evaluation of Bacillus subtilis strains as probiotics and their potential as a food ingredient." Beneficial Microbes 3, no. 2 (2012): 127–35. http://dx.doi.org/10.3920/bm2012.0002.
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Spores of Bacillus subtilis including one strain used commercially were evaluated for their potential value as a probiotic and as potential food additives. Two isolates of B. subtilis examined here were HU58, a human isolate and PXN21, a strain used in an existing commercial product. Compared to a domesticated laboratory strain of B. subtilis both isolates carried traits that could prove advantageous in the human gastro-intestinal tract. This included full resistance to gastric fluids, rapid sporulation and the formation of robust biofilms. We also showed that PXN21 spores when administered weekly to mice conferred non-specific cellular immune responses, indicative signs of the stimulation of innate immunity. Spores mixed in wholemeal biscuits were found to survive baking at 235 °C for 8 minutes with only a 1-log reduction in viability. That spores can survive the baking process offers the possibility of using spores as probiotic supplements in a range of novel food products.
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Puttaiah, Raghunath, Kathy KH Svoboda, Shih Ming Lin, et al. "Evaluation of an Automated Dental Unit Water System's Contamination Control Protocol." Journal of Contemporary Dental Practice 13, no. 1 (2012): 1–10. http://dx.doi.org/10.5005/jp-journals-10024-1087.
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ABSTRACT Background This study addresses the efficacy of an automated decontamination protocol using the germicide ‘tetra acetyl ethylene diamine (TAED) perborate’ (Farmec SpA, Italy). The germicide TAED perborate protocol is used in the Castellini Dental Units fitted with an Autosteril unit (an automated device that can cycle 0.26% TAED perborate solution and sterile water for cleaning the water system between patients and overnight). Prior to testing the Autosteril and the 0.26% TAED perborate protocol on the Logos Jr Dental Unit (Castellini SpA, Italy), TAED perborate was used on a dental unit water system simulation device. Methods A dental unit water system simulation device equipped with four dental unit water systems and with naturally grown and mature biofilm contamination was used in this study (three treatment units and one control). One treatment group used a simulated 5 minutes contact with TAED perborate and sterile water for irrigation; the second used a simulated 5 minutes contact with TAED perborate and 2 ppm ClO2 for irrigation; the third used a simulated 5 minutes contact with TAED perborate and municipal water for irrigation. The control group used municipal water for irrigation with no cleaning/disinfection protocols. This protocol was repeated for 30 cycles. Laser scanning confocal microscopy (LSCM) was used to study the effects on natural and mature biofilms, and R2A agar used to quantify heterotrophic plate counts in the effluent irrigant. Antimicrobial efficacy was evaluated by challenging TAED perborate with microbes and spores (M. smegmatis and B. subtilis). Deleterious effects of the germicide were evaluated on metal and nonmetal parts of dental unit water systems. Heterotrophic plate counts using R2A agar and LSCM of the lines were conducted to assess biofilm and microbial control. Results Baseline water samples showed mean contamination >5.6 log10 cfu/ml. After initial cleaning, all three groups maintained mean contamination levels of less than 1.1 (SD <0.3) log10 cfu/ml. LSCM of baseline samples was positive for live biofilm in all groups. At the end of the study, viable biofilm was only present in the control. In the microbial challenge test, all vegetative organisms were killed within 30 seconds of contact, while spores were killed within 5 minutes. Corrosion was seen in metals used in US-manufactured dental unit materials, while not observed in those used in the Castellini Logos Jr dental unit. Conclusion In this study, the TAED perborate protocol was effective in biofilm control and control of dental treatment water contamination. Use of sterile water or 2 ppm ClO2 along with TAED treatment also controlled planktonic contamination effectively. Clinical significance Environmental biofilms contaminate dental unit water systems over time and affect the quality of dental treatment water. Contaminants include environmental biofilms, microbes, including gram-negative rods and endotoxins in high doses that are not of acceptable quality for treating patients. There are many germicidal protocols for treating this contamination and one such is the prescribed use of TAED perborate used in conjunction with sterile water for irrigation in the autosteril device, an integral component of the Castellini dental units for between patient decontamination of dental unit water systems. This study was conducted on an automated simulation dental unit water system to test the TAED perborate protocol's efficacy on naturally grown, mature environmental biofilms, it's efficacy on microbes and spores and it's effects on materials used in dental unit water systems. This translational research addresses both microbial control and material effects of TAED perborate in studying efficacy and possible deleterious effects and simulated use in dentistry. Currently, this antimicrobial use protocol is followed worldwide in the Castellini dental units that are used in day-to-day dental patient care. How to cite this article Puttaiah R, Svoboda KKH, Lin SM, Montebugnoli L, Dolci G, Spratt D, Siebert J. Evaluation of an Automated Dental Unit Water System's Contamination Control Protocol. J Contemp Dent Pract 2012;13(1):1-10.
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Holzman, David C. "Agent from Soil Microbe Blocks B. subtilis from Forming Biofilms, Spores." Microbe Magazine 10, no. 6 (2015): 230. http://dx.doi.org/10.1128/microbe.10.230.1.
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Doggett, M. Steven. "Characterization of Fungal Biofilms within a Municipal Water Distribution System." Applied and Environmental Microbiology 66, no. 3 (2000): 1249–51. http://dx.doi.org/10.1128/aem.66.3.1249-1251.2000.
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ABSTRACT Biofilms of a municipal water distribution system were characterized to assess the occurrence of fungi within surface matrixes. Densities of filamentous fungi ranged from 4.0 to 25.2 CFU cm−2, whereas yeast densities ranged from 0 to 8.9 CFU cm−2. Observations by scanning electron microscopy further suggested that spores, not hyphae or vegetative cells, comprised the primary source of viable propagules.
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Park, Hyong Seok, Jungwoo Yang, Hee Jung Choi, and Kyoung Heon Kim. "Effective Thermal Inactivation of the Spores of Bacillus cereus Biofilms Using Microwave." Journal of Microbiology and Biotechnology 27, no. 7 (2017): 1209–15. http://dx.doi.org/10.4014/jmb.1702.02009.
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Houry, A., R. Briandet, S. Aymerich, and M. Gohar. "Involvement of motility and flagella in Bacillus cereus biofilm formation." Microbiology 156, no. 4 (2010): 1009–18. http://dx.doi.org/10.1099/mic.0.034827-0.
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Bacillus cereus is a food-borne pathogen and a frequent contaminant of food production plants. The persistence of this pathogen in various environments results from the formation of spores and of biofilms. To investigate the role of the B. cereus flagellar apparatus in biofilm formation, we constructed a non-flagellated mutant and a flagellated but non-motile mutant. Unexpectedly, we found that the presence of flagella decreased the adhesion of the bacterium to glass surfaces. We hypothesize that this decrease is a consequence of the flagella hindering a direct interaction between the bacterial cell wall and the surface. In contrast, in specific conditions, motility promotes biofilm formation. Our results suggest that motility could influence biofilm formation by three mechanisms. Motility is necessary for the bacteria to reach surfaces suitable for biofilm formation. In static conditions, reaching the air–liquid interface, where the biofilm forms, is a strong requirement, whereas in flow cells bacteria can have access to the bottom glass slide by sedimentation. Therefore, motility is important for biofilm formation in glass tubes and in microtitre plates, but not in flow cells. Motility also promotes recruitment of planktonic cells within the biofilm by allowing motile bacteria to invade the whole biofilm. Finally, motility is involved in the spreading of the biofilm on glass surfaces.
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Tirloni, Erica, Simone Stella, Francesco Celandroni, Diletta Mazzantini, Cristian Bernardi, and Emilia Ghelardi. "Bacillus cereus in Dairy Products and Production Plants." Foods 11, no. 17 (2022): 2572. http://dx.doi.org/10.3390/foods11172572.
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Spore-forming Bacillus cereus is a common contaminant of dairy products. As the microorganism is widespread in the environment, it can contaminate milk at the time of milking, but it can also reach the dairy products in each phase of production, storage and ripening. Milk pasteurization treatment is not effective in reducing contamination and can instead act as an activator of spore germination, and a potential associated risk still exists with the consumption of some processed foods. Prevalences and concentrations of B. cereus in milk and dairy products are extremely variable worldwide: in pasteurized milk, prevalences from 2% to 65.3% were reported, with concentrations of up to 3 × 105 cfu/g, whereas prevalences in cheeses ranged from 0 to 95%, with concentrations of up to 4.2 × 106 cfu/g. Bacillus cereus is also well known to produce biofilms, a serious concern for the dairy industry, with up to 90% of spores that are resistant to cleaning and are easily transferred. As the contamination of raw materials is not completely avoidable, and the application of decontamination treatments is only possible for some ingredients and is limited by both commercial and regulatory reasons, it is clear that the correct application of hygienic procedures is extremely important in order to avoid and manage the circulation of B. cereus along the dairy supply chain. Future developments in interventions must consider the synergic application of different mild technologies to prevent biofilm formation and to remove or inactivate the microorganism on the equipment.
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Pirog, T. P., L. V. Kliuchka, T. A. Shevchuk, and G. O. Iutynska. "Destruction of Biofilms on Silicone Tubes under the Action of a Mixture of Nocardia vaccinii IMV B-7405 Surfactants with other Biocides." Mikrobiolohichnyi Zhurnal 83, no. 4 (2021): 43–53. http://dx.doi.org/10.15407/microbiolj83.04.043.
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The formation of pathogenic microorganisms biofilms on the central venous catheter is the cause of catheter-associated infections. An alternative method of combating biofilms is the use of “antibacterial” and “antifungal” locks, which are solutions of antibiotics or antifungal drugs in a mixture with other natural compounds, which can be microbial surface-active substances (surfactants) or essential oils. Aim. To investigate the role of Nocardia vaccinii IMV B-7405 surfactants mixture with other antimicrobial compounds in the destruction of biofilm on silicone tubes. Methods. N. vaccinii IMV B-7405 was grown in medium containing as carbon source purified glycerol and waste from biodiesel production, refined sunflower oil, oil after frying French-fried potatoes, Potato wedges and meat. The surfactants were extracted from supernatant of cultural liquid by modified Folch mixture. 2 mL of surfactant solutions, antifungal drugs (nystatin, fluconazole) or tea tree essential oil of the same concentration (5–640 μg/mL) were added to test tubes with silicone tubes (with pre-formed biofilm from test culture). To study the synergistic effect of the biofilms destruction, a mixture of surfactant solutions and antifungal substances (or essential oil) of the same concentration in a ratio of 1:1 (1 mL of each solution) was added to the test tubes. Sterile tap water (2 mL) was added to control test tubes instead of surfactants preparations, antifungal substances or essential oil. The degree of biofilm destruction (%) was determined as the difference between the adhesion of cells on the inner side of silicone tubes, untreated and treated with surfactants, antifungal drugs, essential oil, or their mixture. Results. It was found that surfactants synthesized by N. vaccinii IMV B-7405 on all substrates showed synergism of yeast and bacterial biofilms destruction on silicone tubes in a mixture with nystatin, fluconazole and tea essential oil in the whole range of investigated concentrations (5–640 μg/mL), but the highest effect was achieved at a concentration of 20–40 μg/mL. Thus, the degree of Candida albicans D-6, Candida utilis BVS-65 and Candida tropicalis PE-2 biofilms destruction under the action of a mixture of surfactants synthesized on waste from the biodiesel production and waste oil, with antifungal drugs was 45.8–71.8% and was higher than with only surfactants (21.2–41.6%), nystatin (22.4–24.1%) or fluconazole (28.1–31.3%). The destruction of Candida genus yeast biofilms under the action of surfactants synthesized on oil-containing substrates in a mixture with both nystatin and fluconazole reached 50.1–71.2%, which is 10–30% higher compared to the use of surfactants alone or only antifungal agents. The degree of Pseudomonas sp. MI-2, Escherichia coli IEM-1, Staphylococcus aureus BMS-1, Bacillus subtilis BT-2 (spores) biofilms destruction on silicone tubes treated with a mixture of tea tree essential oil and surfactants synthesized on all oil-containing substrates was 10–29% higher than in the case of using only solutions of surfactants (11.5–45.4%) or essential oil (21.4–34.5%) for the tubes treatment. Conclusions. The data obtained make it possible to consider surfactants synthesized by N. vaccinii IMV B-7405 on a wide range of cheap and accessible substrates as promising components of “antibacterial” and “antifungal” locks in combination with essential oils and antifungal agents.
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Hoque, Enamul, Stephan Pflugmacher, Johannes Fritscher, and Manfred Wolf. "Induction of Glutathione S-Transferase in Biofilms and Germinating Spores of Mucor hiemalis Strain EH5 from Cold Sulfidic Spring Waters." Applied and Environmental Microbiology 73, no. 8 (2007): 2697–707. http://dx.doi.org/10.1128/aem.02786-06.
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ABSTRACT The occurrence and activation of glutathione S-transferase (GST) and the GST activities in biofilms in cold sulfidic spring waters were compared to the occurrence and activation of GST and the GST activities of the aquatic fungal strains EH5 and EH7 of Mucor hiemalis isolated for the first time from such waters. Using fluorescently labeled polyclonal anti-GST antibodies and GST activity measurements, we demonstrated that a high level of GST occurred in situ in natural biofilms and pure cultures of strain EH5. Measurement of microsomal and cytosolic soluble GST activities using different xenobiotic substrates, including 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene, 1,2-epoxy-3-(4-nitrophenoxy)propane, 1-iodo-2,4-dinitrobenzene, and fluorodifen, showed that the overall biotransforming abilities of biofilms were at least sixfold greater than that of strain EH5 alone. Increasing the level of sodium thiosulfate (STS) in the medium stimulated the microsomal and cytosolic GST activities with CDNB of strain EH5 about 44- and 94-fold, respectively, compared to the activities in the control. The induction of microsomal GST activity with fluorodifen by STS was strongly linear, but the initial strong linear increase in cytosolic GST activity with fluorodifen showed saturation-like effects at STS concentrations higher than approximately 1 mM. Using laser scanning confocal and conventional fluorescence microscopy, abundant fluorescently labeled GST proteins were identified in germinating sporangiospores of strain EH5 after activation by STS. High-performance size exclusion chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of at least two main GSTs (∼27.8- and ∼25.6-kDa subunits) in the cytosol of EH5, whereas the major 27.8-kDa subunit was the only GST in microsomes. We suggest that differential cellular GST expression takes place in strain EH5 depending on spore and hyphal development. Our results may contribute to our understanding of induction of GST by sulfurous compounds, as well as to the immunofluorescence visualization of GST in aquatic fungus and fungus-bacterium biofilms.
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Hosni, Ahmed A., Jeffery G. Szabo, and Paul L. Bishop. "Efficacy of Chlorine Dioxide as a Disinfectant for Bacillus Spores in Drinking-Water Biofilms." Journal of Environmental Engineering 137, no. 7 (2011): 569–74. http://dx.doi.org/10.1061/(asce)ee.1943-7870.0000355.
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Rabochová, M., M. Kulišová, J. Lorinčík, et al. "Assessing the antimicrobial efficacy of nonthermal plasma treatment on filamentous fungi spores and biofilms." Food Control 163 (September 2024): 110522. http://dx.doi.org/10.1016/j.foodcont.2024.110522.
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SVENSSON, BIRGITTA, ÅSA ENEROTH, JOHANNE BRENDEHAUG, GÖRAN MOLIN, and ANDERS CHRISTIANSSON. "Involvement of a pasteurizer in the contamination of milk by Bacillus cereus in a commercial dairy plant." Journal of Dairy Research 67, no. 3 (2000): 455–60. http://dx.doi.org/10.1017/s0022029900004313.
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Bacillus cereus is a common contaminant in raw milk. The spores survive pasteurization and psychrotrophic strains of B. cereus often limit the keeping quality of pasteurized milk stored at > 6 °C (Griffiths, 1992). High numbers of B. cereus in pasteurized milk are most frequent when the cows are grazing (Slaghuis et al. 1997), mainly owing to increased levels of spores in raw milk resulting from teat contamination by soil (Christiansson et al. 1999). However, high numbers can also be found in pasteurized milk while the cows are housed indoors, and this is probably caused by additional contamination at the dairy plant (te Giffel et al. 1996; Larsen & Jørgensen, 1997; Lin et al. 1998). There is little information available about the sites of recontamination in the dairy. The use of typing techniques capable of discrimination below the species level, such as fatty acid profiles and random amplification of polymorphic DNA–polymerase chain reaction (RAPD–PCR), could be helpful in demonstrating contamination routes (Lin et al. 1998; Nilsson et al. 1998).Spores of B. cereus are very hydrophobic and readily adhere to surfaces of steel, glass and rubber (Rönner et al. 1990), and short cleaning-in-place programmes do not always eliminate all the spores (Rönner & Husmark, 1992). Spores adhering to surfaces are more difficult to eliminate by disinfectants than spores in solution (te Giffel et al. 1995). Many B. cereus spores germinate rapidly in milk upon heat activation and, if allowed to propagate undisturbed on surfaces, may form biofilms that are extremely difficult to eliminate (Mosteller & Bishop, 1993; Wirtanen et al. 1996; Kumar & Anand, 1998).This paper describes how we demonstrated the involvement of a pasteurizer in the contamination of pasteurized milk by B. cereus in a commercial dairy plant using a combination of classic microbiological analyses and typing of strains by RAPD–PCR.
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Giglio, Krista M., Chengjun Zhu, Courtney Klunder, Shelley Kummer, and Anthony G. Garza. "The Enhancer Binding Protein Nla6 Regulates Developmental Genes That Are Important for Myxococcus xanthus Sporulation." Journal of Bacteriology 197, no. 7 (2015): 1276–87. http://dx.doi.org/10.1128/jb.02408-14.
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ABSTRACTIn the bacteriumMyxococcus xanthus, starvation triggers the formation of multicellular fruiting bodies containing thousands of stress-resistant spores. Recent work showed that fruiting body development is regulated by a cascade of transcriptional activators called enhancer binding proteins (EBPs). The EBP Nla6 is a key component of this cascade; it regulates the promoters of other EBP genes, including a downstream-functioning EBP gene that is crucial for sporulation. In recent expression studies, hundreds of Nla6-dependent genes were identified, suggesting that the EBP gene targets of Nla6 may be part of a much larger regulon. The goal of this study was to identify and characterize genes that belong to the Nla6 regulon. Accordingly, a direct repeat [consensus, C(C/A)ACGNNGNC] binding site for Nla6 was identified usingin vitroandin vivomutational analyses, and the sequence was subsequently used to find 40 potential developmental promoter (88 gene) targets. We showed that Nla6 binds to the promoter region of four new targets (asgE,exo, MXAN2688, and MXAN3259)in vitroand that Nla6 is important for their normal expressionin vivo. Phenotypic studies indicate that all of the experimentally confirmed targets of Nla6 are primarily involved in sporulation. These targets include genes involved in transcriptional regulation, cell-cell signal production, and spore differentiation and maturation. Although sporulation occurs late in development, all of the developmental loci analyzed here show an Nla6-dependent burst in expression soon after starvation is induced. This finding suggests that Nla6 starts preparing cells for sporulation very early in the developmental process.IMPORTANCEBacterial development yields a remarkable array of complex multicellular forms. One such form, which is commonly found in nature, is a surface-associated aggregate of cells known as a biofilm. Mature biofilms are structurally complex and contain cells that are highly resistant to antibacterial agents. When starving, the model bacteriumMyxococcus xanthusforms a biofilm containing a thin mat of cells and multicellular structures that house a highly resistant cell type called a myxospore. Here, we identify the promoter binding site of the transcriptional activator Nla6, identify genes in the Nla6 regulon, and show that several of the genes in the Nla6 regulon are important for production of stress-resistant spores in starvation-inducedM. xanthusbiofilms.
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Tsarelunga, А. А., and Е. Yu Blagoveschenskaya. "Phylloplane as fungi habitat." Журнал общей биологии 84, no. 4 (2023): 263–78. http://dx.doi.org/10.31857/s0044459623040073.
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As currently shown the phylloplane of different plants is actively colonized by yeasts and filamentous fungi of different taxonomic groups. The features of the leaf as a microhabitat are low humidity, susceptibility to mechanical effects of rain and wind, lack of nutrients on the surface, and high insolation, which causes the allocation of epiphytic fungi as a separate ecological group. Although the data vary from plant to plant, in general it can be said that basidial yeasts and such filamentous fungi as Alternaria, Epicoccum, Cladosporium, Phoma and Trichoderma are most commonly found on plant surfaces. The biological cycle of epiphytic fungi has not yet been studied, but it is assumed that it begins with the specific adhesion of the spore on the surface, followed by the formation of biofilms or the so-called “aggregates” that combine bacteria, yeast and filamentous fungi and ends with the formation of spores either on the surface of a living plant or on dead and decaying leaves.
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Schuerger, Andrew C., Steven Trigwell, and Carlos I. Calle. "Use of non-thermal atmospheric plasmas to reduce the viability ofBacillus subtilison spacecraft surfaces." International Journal of Astrobiology 7, no. 1 (2008): 47–57. http://dx.doi.org/10.1017/s1473550407004016.
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AbstractAtmospheric pressure glow-discharge (APGD) plasmas have been proposed for sterilizing spacecraft surfaces prior to launch. The advantages of APGD plasmas for the sterilization of spacecraft surfaces include low temperatures at treatment sites, rapid inactivation kinetics of exposed microbial cells, physical degradation and removal of microbial cells, physical removal of organic biosignature molecules, and short exposure times for the materials. However, few studies have tested APGD plasmas on spacecraft materials for their effectiveness in both sterilizing surfaces and removal of microbial cells or spores. A helium (He)+oxygen (O2) APGD plasma was used to expose six spacecraft materials (aluminum 6061, polytetrafluoroethylene (PTFE), polycarbonate, Saf-T-Vu, Rastex, and Herculite 20) doped with spores of the common spacecraft contaminant,Bacillus subtilis, for periods of time up to 6 min. Results indicated that greater than six orders of magnitude reductions in viability were observed forB. subtilisspores in as short of time as 40 s exposure to the APGD plasmas. Spacecraft materials were not affected by exposures to the APGD plasmas. However, Saf-T-Vu was the only material in which spores ofB. subtilisadhered more aggressively to plasma-treated coupons when compared to non-plasma treated coupons; all other materials exhibited no significant differences between plasma and non-plasma treated coupons. In addition, spores ofB. subtiliswere physically degraded by exposures to the plasmas beginning at the terminal ends of spores, which appeared to be ruptured after only 30 s. After 300 s, most bacteria were removed from aluminium coupons, and only subtle residues of bacterial secretions or biofilms remained. Results support the conclusion that APGD plasmas can be used as a prelaunch cleaning and sterilization treatment on spacecraft materials provided that the biocidal and cleaning times are shorter than those required to alter surface properties of materials.
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Mowat, Eilidh, John Butcher, Sue Lang, Craig Williams, and Gordon Ramage. "Development of a simple model for studying the effects of antifungal agents on multicellular communities of Aspergillus fumigatus." Journal of Medical Microbiology 56, no. 9 (2007): 1205–12. http://dx.doi.org/10.1099/jmm.0.47247-0.
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Aspergillus fumigatus is an increasingly prevalent opportunistic fungal pathogen of various immunocompromised individuals. It has the ability to form filaments within the lungs, producing dense intertwined mycelial balls, which are difficult to treat. The aim of this study was to develop a suitable model of A. fumigatus to examine the effects of antifungal challenge on these intertwined filamentous communities. A. fumigatus NCPF 7367 growth conditions were optimized on both Thermanox coverslips and on flat-bottomed microtitre plates to establish optimal conidial seeding densities. Isolates were treated with itraconazole, voriconazole, amphotericin B and caspofungin and their overall killing efficiency was measured using an XTT formazan metabolic dye assay. This was compared with the CLSI (formerly NCCLS) methodology of broth microdilution of moulds (standard M38-A). It was shown that 1×105 conidia ml−1 in RPMI 1640 was the optimum concentration of spores for biofilm formation. Filamentous growth characteristics were not observed until 10 h incubation, followed by an exponential increase in the biofilm biomass (hyphae and extracellular material) and cellular activity (metabolism). When susceptibility testing of biofilms was compared with that of planktonic cells by CLSI broth microdilution testing, all antifungal drugs were at least 1000 times less effective at reducing the overall metabolic activity of 90 % of the cells. Overall, this study showed that A. fumigatus has the ability to form coherent multicellular biofilm structures that are resistant to the effects of antifungal drugs.
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Engel, Tobias, Paul E. Verweij, Joost van den Heuvel, et al. "Parasexual recombination enables Aspergillus fumigatus to persist in cystic fibrosis." ERJ Open Research 6, no. 4 (2020): 00020–2020. http://dx.doi.org/10.1183/23120541.00020-2020.
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Aspergillus fumigatus is a saprobic fungus that causes a range of pulmonary diseases, some of which are characterised by fungal persistence such as is observed in cystic fibrosis (CF) patients. Creation of genetic variation is critical for A. fumigatus to adapt to the lung environment, but biofilm formation, especially in CF patients, may preclude mutational supply in A. fumigatus due to its confinement to the hyphal morphotype. We tested our hypothesis that genetic variation is created through parasexual recombination in chronic biofilms by phenotypic and genetic analysis of A. fumigatus isolates cultured from different origins.As diploids are the hallmark of parasex, we screened 799 A. fumigatus isolates obtained from patients with CF, chronic pulmonary lung disease and acute invasive aspergillosis, and from the environment for spore size. Benomyl sensitivity, nuclear content measurements through fluorescence-activated cell sorting and scanning electron microscopy were used to confirm the diploid state of large size spores. Whole genome sequencing was used to characterise diploid-associated genetic variation.We identified 11 diploids in isolates recovered from six of 11 (55%) CF patients and from one of 24 (4%) chronic aspergillosis patients, but not in 368 isolates from patients with acute Aspergillus infection and the environment. Diploid formation was associated with accumulation of mutations and variable haploid offspring including a voriconazole-resistant isolate.Parasexual recombination allows A. fumigatus to adapt and persist in CF patients, and plays a role in azole resistance development. Our findings are highly significant for understanding the genetics and biology of A. fumigatus in the human lung.
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Mohsin, Muhammad Zubair, Rabia Omer, Jiaofang Huang, et al. "Advances in engineered Bacillus subtilis biofilms and spores, and their applications in bioremediation, biocatalysis, and biomaterials." Synthetic and Systems Biotechnology 6, no. 3 (2021): 180–91. http://dx.doi.org/10.1016/j.synbio.2021.07.002.
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AXELSSON, L., A. HOLCK, I. RUD, et al. "Cleaning of Conveyor Belt Materials Using Ultrasound in a Thin Layer of Water." Journal of Food Protection 76, no. 8 (2013): 1401–7. http://dx.doi.org/10.4315/0362-028x.jfp-12-563.
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Cleaning of conveyor belts in the food industry is imperative for preventing the buildup of microorganisms that can contaminate food. New technologies for decreasing water and energy consumption of cleaning systems are desired. Ultrasound can be used for cleaning a wide range of materials. Most commonly, baths containing fairly large amounts of water are used. One possibility to reduce water consumption is to use ultrasonic cavitation in a thin water film on a flat surface, like a conveyor belt. In order to test this possibility, a model system was set up, consisting of an ultrasound transducer/probe with a 70-mm-diameter flat bottom, operating at 19.8 kHz, and contaminated conveyor belt materials in the form of coupons covered with a thin layer of water or water with detergent. Ultrasound was then applied on the water surface at different power levels (from 46 to 260 W), exposure times (10 and 20 s), and distances (2 to 20 mm). The model was used to test two different belt materials with various contamination types, such as biofilms formed by bacteria in carbohydrate- or protein-fat–based soils, dried microorganisms (bacteria, yeasts, and mold spores), and allergens. Ultrasound treatment increased the reduction of bacteria and yeast by 1 to 2 log CFU under the most favorable conditions compared with water or water-detergent controls. The effect was dependent on the type of belt material, the power applied, the exposure time, and the distance between the probe and the belt coupon. Generally, dried microorganisms were more easily removed than biofilms. The effect on mold spores was variable and appeared to be species and material dependent. Spiked allergens were also efficiently removed by using ultrasound. The results in this study pave the way for new cleaning designs for flat conveyor belts, with possibilities for savings of water, detergent, and energy consumption.
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Khan, Mahjabeen, Murray McDonald, Kaustubh Mundada, and Mark Willcox. "Efficacy of Ultraviolet Radiations against Coronavirus, Bacteria, Fungi, Fungal Spores and Biofilm." Hygiene 2, no. 3 (2022): 120–31. http://dx.doi.org/10.3390/hygiene2030010.
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Ultra-violet (UV) C (200–280 wavelength) light has long been known for its antimicrobial and disinfecting efficacy. It damages DNA by causing the dimerization of pyrimidines. A newly designed technology (MUVi-UVC; Mobile UV Innovations Pty Ltd., Melbourne, VIC, Australia) that emits UVC at 240 nm is composed of an enclosed booth with three UVC light stands each with four bulbs, and has been developed for disinfecting mobile medical equipment. The aim of this project was to examine the spectrum of antimicrobial activity of this device. The experiments were designed following ASTM E1052-20, EN14561, BSEN14476-2005, BSEN14562-2006 and AOAC-Official-Method-966.04 standards for surface disinfection after drying microbes on surfaces. The disinfection was analyzed using Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (6294), Candida auris (CBS 12373), spores of Aspergillus niger (ATCC 16404), coronavirus (SARS-CoV-2 surrogate ATCC VR-261) as well as a methicillin-resistant Staphylococcus aureus (SA31), a carbapenem- and polymyxin-resistant Pseudomonas aeruginosa (PA219), Escherichia coli K12 (ATCC 10798) and Salmonella typhi (ATCC 700730). The parameters of time, the number of lights and direction of the sample facing the lights were examined. The MUVi-UVC was able to kill 99.999% of all of the tested bacteria, fungi, coronavirus and bacteria in the biofilms if used for 5 min using all three lights in the setup with the glass slides in a vertical position. However, for fungal spores, 30 min were required to achieve 99.999% killing. There was a small but insignificant effect of having the surface horizontally or vertically aligned to the UV lights. Therefore, this UVC device is an effective technology to disinfect medical devices.
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Huang, Yiying, Steve H. Flint, and Jon S. Palmer. "The heat resistance of spores from biofilms of Bacillus cereus grown in tryptic soy broth and milk." International Dairy Journal 123 (December 2021): 105169. http://dx.doi.org/10.1016/j.idairyj.2021.105169.
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Koval’ová, Zuzana, Kataŕna Tarabová, Karol Hensel, and Zdenko Machala. "Decontamination of Streptococci biofilms and Bacillus cereus spores on plastic surfaces with DC and pulsed corona discharges." European Physical Journal Applied Physics 61, no. 2 (2013): 24306. http://dx.doi.org/10.1051/epjap/2012120449.
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Prado, Daniela Biral do, Márcia Maria dos Anjos Szczerepa, Otávio Augusto Capeloto, et al. "Effect of ultraviolet (UV-C) radiation on spores and biofilms of Alicyclobacillus spp. in industrialized orange juice." International Journal of Food Microbiology 305 (September 2019): 108238. http://dx.doi.org/10.1016/j.ijfoodmicro.2019.108238.
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Akishev, Yuri, Michail Grushin, Vladimir Karalnik, et al. "Atmospheric-pressure, nonthermal plasma sterilization of microorganisms in liquids and on surfaces." Pure and Applied Chemistry 80, no. 9 (2008): 1953–69. http://dx.doi.org/10.1351/pac200880091953.
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Gas discharge plasma inactivation of microorganisms at low (close to ambient) temperature is a promising area of investigation that is attracting widespread interest. This paper describes atmospheric-pressure, nonthermal plasma (NTP) methods for cold sterilization of liquids and thermal sensitive surfaces. These methods are based on the use of direct current (DC) gas discharge plasma sources fed with steady-state high voltage. Parameters characterizing the plasma sources used (plasma-forming gas, gas flow rate, electric power consumed, etc.) are given. The results for plasma sterilization of different microorganisms (vegetative cells, spores, fungi, biofilms) are presented. An empirical mathematical approach is developed for describing NTP inactivation of microorganisms. This approach takes into account not only the destruction of different components of the cells, but their reparation as well.
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Gómez-Pérez, Daniel, Vasvi Chaudhry, Ariane Kemen, and Eric Kemen. "Amyloid Proteins in Plant-Associated Microbial Communities." Microbial Physiology 31, no. 2 (2021): 88–98. http://dx.doi.org/10.1159/000516014.
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Amyloids have proven to be a widespread phenomenon rather than an exception. Many proteins presenting the hallmarks of this characteristic beta sheet-rich folding have been described to date. Particularly common are functional amyloids that play an important role in the promotion of survival and pathogenicity in prokaryotes. Here, we describe important developments in amyloid protein research that relate to microbe-microbe and microbe-host interactions in the plant microbiome. Starting with biofilms, which are a broad strategy for bacterial persistence that is extremely important for plant colonization. Microbes rely on amyloid-based mechanisms to adhere and create a protective coating that shelters them from external stresses and promotes cooperation. Another strategy generally carried out by amyloids is the formation of hydrophobic surface layers. Known as hydrophobins, these proteins coat the aerial hyphae and spores of plant pathogenic fungi, as well as certain bacterial biofilms. They contribute to plant virulence through promoting dissemination and infectivity. Furthermore, antimicrobial activity is an interesting outcome of the amyloid structure that has potential application in medicine and agriculture. There are many known antimicrobial amyloids released by animals and plants; however, those produced by bacteria or fungi remain still largely unknown. Finally, we discuss amyloid proteins with a more indirect mode of action in their host interactions. These include virulence-promoting harpins, signaling transduction that functions through amyloid templating, and root nodule bacteria proteins that promote plant-microbe symbiosis. In summary, amyloids are an interesting paradigm for their many functional mechanisms linked to bacterial survival in plant-associated microbial communities.
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KOSEKI, SHIGENOBU, KYOICHIRO YOSHIDA, SEIICHIRO ISOBE, and KAZUHIKO ITOH. "Decontamination of Lettuce Using Acidic Electrolyzed Water." Journal of Food Protection 64, no. 5 (2001): 652–58. http://dx.doi.org/10.4315/0362-028x-64.5.652.
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The disinfectant effect of acidic electrolyzed water (AcEW), ozonated water, and sodium hypochlorite (NaOCl) solution on lettuce was examined. AcEW (pH 2.6; oxidation reduction potential, 1140 mV; 30 ppm of available chlorine) and NaOCl solution (150 ppm of available chlorine) reduced viable aerobes in lettuce by 2 log CFU/g within 10 min. For lettuce washed in alkaline electrolyzed water (AlEW) for 1 min and then disinfected in AcEW for 1 min, viable aerobes were reduced by 2 log CFU/g. On the other hand, ozonated water containing 5 ppm of ozone reduced viable aerobes in lettuce 1.5 log CFU/g within 10 min. It was discovered that AcEW showed a higher disinfectant effect than did ozonated water significantly at P &lt; 0.05. It was confirmed by swabbing test that AcEW, ozonated water, and NaOCl solution removed aerobic bacteria, coliform bacteria, molds, and yeasts on the surface of lettuce. Therefore, residual microorganisms after the decontamination of lettuce were either in the inside of the cellular tissue, such as the stomata, or making biofilm on the surface of lettuce. Biofilms were observed by a scanning electron microscope on the surface of the lettuce treated with AcEW. Moreover, it was shown that the spores of bacteria on the surface were not removed by any treatment in this study. However, it was also observed that the surface structure of lettuce was not damaged by any treatment in this study. Thus, the use of AcEW for decontamination of fresh lettuce was suggested to be an effective means of controlling microorganisms.
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Syrchina, N. V., L. V. Pilip, E. P. Kolevatykh, and T. Ya Ashikhmina. "Effect of various processing methods on the numbers of Clostridium (Clostridia, Bacteria) in animal by-products." Povolzhskiy Journal of Ecology, no. 4 (December 12, 2023): 466–80. http://dx.doi.org/10.35885/1684-7318-2023-4-466-480.
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Clostridia are one of the largest genera of eubacteria living in water, soil, the intestines of humans and animals. The genus Clostridium includes both pathogenic and non-pathogenic species. Representatives of this genus occupy a leading position among all types of bacteria in producing a variety of toxins. Due to their ability to form spores, these microorganisms can survive in the most unfavorable conditions. Antibiotic-resistant Clostridia, which are released to the environment as part of farm animal manure, are of particular environmental danger. We have studied the influence of various treatment methods (aeration, acidification, and surfactant application) of the liquid fraction of pig manure effluents (ME) on the species composition and the numbers of Clostridia. Cl. septicum and Cl. perfringens were found to occupy a dominant position in the ME of manure storage baths. Both species are actively involved in the ammonification of organic compounds, releasing a wide range of volatile substances with an unpleasant odor into the environment. Most of the Clostridia were detected in biofilms formed on the surface of ME under anaerobic conditions. Such conditions are formed during storage of the liquid fraction in closed lagoons, which increases the environmental risks of the release of undesirable microorganisms into the environment. Round-the-clock aeration and acidification of ME to pH 5.5 reduce the numbers of Clostridia. Such conditions contribute to the formation of microorganism consortia with fungi to occupy a dominant position. Cl. difficile (32.52%), Cl. putrificum (31.62%) and Cl. septicum (30.72%) predominated in biofilms of acidified ME, whilst only Cl. difficile (69.98–95.26%) did in options with surfactants added. The largest relative numbers of pathogenic Cl. difficile (95.26%) were observed in the option with the addition of a cationic surfactant (benzalkonium chloride).
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Rao, Dhana, Jeremy S. Webb, Carola Holmström, et al. "Low Densities of Epiphytic Bacteria from the Marine Alga Ulva australis Inhibit Settlement of Fouling Organisms." Applied and Environmental Microbiology 73, no. 24 (2007): 7844–52. http://dx.doi.org/10.1128/aem.01543-07.
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ABSTRACT Bacteria that produce inhibitory compounds on the surface of marine algae are thought to contribute to the defense of the host plant against colonization of fouling organisms. However, the number of bacterial cells necessary to defend against fouling on the plant surface is not known. Pseudoalteromonas tunicata and Phaeobacter sp. strain 2.10 (formerly Roseobacter gallaeciensis) are marine bacteria often found in association with the alga Ulva australis and produce a range of extracellular inhibitory compounds against common fouling organisms. P. tunicata and Phaeobacter sp. strain 2.10 biofilms with cell densities ranging from 102 to 108 cells cm−2 were established on polystyrene petri dishes. Attachment and settlement assays were performed with marine fungi (uncharacterized isolates from U. australis), marine bacteria (Pseudoalteromonas gracilis, Alteromonas sp., and Cellulophaga fucicola), invertebrate larvae (Bugula neritina), and algal spores (Polysiphonia sp.) and gametes (U. australis). Remarkably low cell densities (102 to 103 cells cm−2) of P. tunicata were effective in preventing settlement of algal spores and marine fungi in petri dishes. P. tunicata also prevented settlement of invertebrate larvae at densities of 104 to 105 cells cm−2. Similarly, low cell densities (103 to 104cells cm−2) of Phaeobacter sp. strain 2.10 had antilarval and antibacterial activity. Previously, it has been shown that abundance of P. tunicata on marine eukaryotic hosts is low (<1 × 103 cells cm−2) (T. L. Skovhus et al., Appl. Environ. Microbiol. 70:2373-2382, 2004). Despite such low numbers of P. tunicata on U. australis in situ, our data suggest that P. tunicata and Phaeobacter sp. strain 2.10 are present in sufficient quantities on the plant to inhibit fouling organisms. This strongly supports the hypothesis that P. tunicata and Phaeobacter sp. strain 2.10 can play a role in defense against fouling on U. australis at cell densities that commonly occur in situ.
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Karkalic, Radovan, Mina Mandic, Jasmina Nikodinovic-Runic, Dalibor Jovanovic, Zoran Lukovic, and Sandra Vojnovic. "Antimicrobial and anti-biofilm activity and biological decontamination efficiency of ED-1 emulsion." Journal of the Serbian Chemical Society 84, no. 1 (2019): 99–110. http://dx.doi.org/10.2298/jsc180716087k.
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Antimicrobial and antibiofilm activity, as well as biological decontamination potential of emulsion ED-1, highly efficient in radiological decontamination of metal surfaces contaminated with uranium isotopes, was assessed. The antimicrobial potency of ED-1 was evaluated against 10 different microorganisms including four Gram-negative bacteria (Acinetobacter baumannii ATCC 19606, Escherichia coli NCTC 9001, Klebsiella pneumoniae ATCC 13803 and Pseudomonas aeruginosa NCTC 10662), four Gram-positive bacteria (Enterococcus faecalis ATCC 29212, Enterococcus faecium ATCC 6057, Listeria monocytogenes NCTC 11994, Staphylococcus aureus NCTC 6571) and two fungi (Candida albicans ATCC 10231 and Candida parapsilosis ATCC 22019). Although without strong bactericidal and fungicidal properties in standard agar diffusion assays, ED-1 effectively inhibited the growth of P. aeruginosa cells in liquid culture and more importantly, showed high potential to disperse P. aeruginosa biofilms. ED-1 was also capable to efficiently remove Bacillus subtilis ATCC 6633 spores in quantitative and a semi-quantitative biological decontamination tests on metal surfaces. Antimicrobial and antibiofilm activity and biological decontamination efficiency of ED-1 was comparable to and better than that of calcium hypochlorite solution or commercial decontaminant BX-24. This study highlighted the possibility to use ED-1, with up to 5-fold reduced amounts of calcium hypochlorite in comparison to currently used methodology, for both biological and radiological decontamination, resulting in both environmental and financial benefits.