Displaying publications 41 - 60 of 318 in total

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  1. The influence of dissolved oxygen level and medium on biofilm formation by Campylobacter jejuni
    Teh AHT, Lee SM, Dykes GA
    Food Microbiol, 2017 Feb;61:120-125.
    PMID: 27697161 DOI: 10.1016/j.fm.2016.09.008
    Campylobacter jejuni survival in aerobic environments has been suggested to be mediated by biofilm formation. Biofilm formation by eight C. jejuni strains under both aerobic and microaerobic conditions in different broths (Mueller-Hinton (MH), Bolton and Brucella) was quantified. The dissolved oxygen (DO) content of the broths under both incubation atmospheres was determined. Biofilm formation for all strains was highest in MH broth under both incubation atmospheres. Four strains had lower biofilm formation in MH under aerobic as compared to microaerobic incubation, while biofilm formation by the other four strains did not differ under the 2 atm. Two strains had higher biofilm formation under aerobic as compared to microaerobic atmospheres in Bolton broth. Biofilm formation by all other strains in Bolton, and all strains in Brucella broth, did not differ under the 2 atm. Under aerobic incubation DO levels in MH > Brucella > Bolton broth. Under microaerobic conditions levels in MH = Brucella > Bolton broth. Levels of DO in MH and Brucella broth were lower under microaerobic conditions but those of Bolton did not differ under the 2 atm. Experimental conditions and especially the DO of broth media confound previous conclusions drawn about aerobic biofilm formation by C. jejuni.
    Matched MeSH terms: Biofilms/growth & development*
  2. Fulltext Evaluation of algal biofilms on indium tin oxide (ITO) for use in biophotovoltaic platforms based on photosynthetic performance
    Ng FL, Phang SM, Periasamy V, Yunus K, Fisher AC
    PLoS One, 2014;9(5):e97643.
    PMID: 24874081 DOI: 10.1371/journal.pone.0097643
    In photosynthesis, a very small amount of the solar energy absorbed is transformed into chemical energy, while the rest is wasted as heat and fluorescence. This excess energy can be harvested through biophotovoltaic platforms to generate electrical energy. In this study, algal biofilms formed on ITO anodes were investigated for use in the algal biophotovoltaic platforms. Sixteen algal strains, comprising local isolates and two diatoms obtained from the Culture Collection of Marine Phytoplankton (CCMP), USA, were screened and eight were selected based on the growth rate, biochemical composition and photosynthesis performance using suspension cultures. Differences in biofilm formation between the eight algal strains as well as their rapid light curve (RLC) generated using a pulse amplitude modulation (PAM) fluorometer, were examined. The RLC provides detailed information on the saturation characteristics of electron transport and overall photosynthetic performance of the algae. Four algal strains, belonging to the Cyanophyta (Cyanobacteria) Synechococcus elongatus (UMACC 105), Spirulina platensis. (UMACC 159) and the Chlorophyta Chlorella vulgaris (UMACC 051), and Chlorella sp. (UMACC 313) were finally selected for investigation using biophotovoltaic platforms. Based on power output per Chl-a content, the algae can be ranked as follows: Synechococcus elongatus (UMACC 105) (6.38×10(-5) Wm(-2)/µgChl-a)>Chlorella vulgaris UMACC 051 (2.24×10(-5) Wm(-2)/µgChl-a)>Chlorella sp.(UMACC 313) (1.43×10(-5) Wm(-2)/µgChl-a)>Spirulina platensis (UMACC 159) (4.90×10(-6) Wm(-2)/µgChl-a). Our study showed that local algal strains have potential for use in biophotovoltaic platforms due to their high photosynthetic performance, ability to produce biofilm and generation of electrical power.
    Matched MeSH terms: Biofilms*
  3. Fulltext Does Campylobacter jejuni form biofilms in food-related environments?
    Teh AH, Lee SM, Dykes GA
    Appl Environ Microbiol, 2014 Sep;80(17):5154-60.
    PMID: 24928882 DOI: 10.1128/AEM.01493-14
    Campylobacter jejuni is one of the most frequent causes of bacterial gastrointestinal food-borne infection worldwide. This species is part of the normal flora of the gastrointestinal tracts of animals used for food production, including poultry, which is regarded as the primary source of human Campylobacter infections. The survival and persistence of C. jejuni in food processing environments, especially in poultry processing plants, represent significant risk factors that contribute to the spread of this pathogen through the food chain. Compared to other food-borne pathogens, C. jejuni is more fastidious in its growth requirements and is very susceptible to various environmental stressors. Biofilm formation is suggested to play a significant role in the survival of C. jejuni in the food production and processing environment. The aims of this minireview were (i) to examine the evidence that C. jejuni forms biofilms and (ii) to establish the extent to which reported and largely laboratory-based studies of C. jejuni biofilms provide evidence for biofilm formation by this pathogen in food processing environments. Overall existing studies do not provide strong evidence for biofilm formation (as usually defined) by most C. jejuni strains in food-related environments under the combined conditions of atmosphere, temperature, and shear that they are likely to encounter. Simple attachment to and survival on surfaces and in existing biofilms of other species are far more likely to contribute to C. jejuni survival in food-related environments based on our current understanding of this species.
    Matched MeSH terms: Biofilms/growth & development*
  4. Adhesion of Pseudomonas fluorescens biofilms to glass, stainless steel and cellulose
    Wan Dagang WR, Bowen J, O'Keeffe J, Robbins PT, Zhang Z
    Biotechnol Lett, 2016 May;38(5):787-92.
    PMID: 26892223 DOI: 10.1007/s10529-016-2047-x
    The adhesion of colloidal probes of stainless steel, glass and cellulose to Pseudomonas fluorescens biofilms was examined using atomic force microscopy (AFM) to allow comparisons between surfaces to which biofilms might adhere.
    Matched MeSH terms: Biofilms
  5. Characterization of multiscale interactions between high intensity focused ultrasound (HIFU) and tooth dentin: the effect on matrix-metalloproteinases, bacterial biofilms and biological properties
    Daood U, Aati S, Akram Z, Yee J, Yong C, Parolia A, et al.
    Biomater Sci, 2021 Jul 27;9(15):5344-5358.
    PMID: 34190236 DOI: 10.1039/d1bm00555c
    The aim of this study was to characterize multiscale interactions between high intensity focused ultrasound (HIFU) and dentin collagen and associated matrix-metalloproteinases, in addition to the analysis of the effect of HIFU on bacterial biofilms and biological properties. Dentin specimens were subjected to 5, 10 or 20 s HIFU. XPS spectra were acquired and TEM was performed on dentin slabs. Collagen orientation was performed using Raman spectroscopy. Calcium measurements in human dental pulpal cells (hDPCs) were carried out after 7 and 14 days. For macrophages, CD36+ and CD163+ were analysed. Biofilms were analyzed using CLSM. Tandem mass spectroscopy was performed for the detection of hydroxyproline sequences along with human MMP-2 quantification. Phosphorus, calcium, and nitrogen were detected in HIFU specimens. TEM images demonstrated the collagen network appearing to be fused together in the HIFU 10 and 20 s specimens. The band associated with 960 cm-1 corresponds to the stretching ν1 PO43-. The control specimens showed intensive calcium staining followed by HIFU 20 s > HIFU 10 s > HIFU 5 s specimens. Macrophages in the HIFU specimens co-expressed CD80+ and CD163+ cells. CLSM images showed the HIFU treatment inhibiting bacterial growth. SiteScore propensity determined the effect of HIFU on the binding site with a higher DScore representing better site exposure on MMPs. Multiscale mapping of dentin collagen after HIFU treatment showed no deleterious alterations on the organic structure of dentin.
    Matched MeSH terms: Biofilms
  6. Streptococcus salivarius K12 inhibits Candida albicans aggregation, biofilm formation and dimorphism
    Mokhtar M, Rismayuddin NAR, Mat Yassim AS, Ahmad H, Abdul Wahab R, Dashper S, et al.
    Biofouling, 2021 08;37(7):767-776.
    PMID: 34425729 DOI: 10.1080/08927014.2021.1967334
    Candida albicans causes candidiasis, particularly in immunocompromised patients. Streptococcus salivarius K12 (K12) is a probiotic isolated from a healthy oral cavity. The study aimed to determine the effect of K12 on C. albicans aggregation, biofilm formation and dimorphism. C. albicans ATCC MYA-4901, acquired immunodeficiency syndrome (AIDS) isolate (ALC2), and oral cancer isolate (ALC3) and K12 were used in the study. All C. albicans strains and K12 were grown in yeast peptone dextrose agar and brain heart infusion agar, respectively, prior to aggregation, biofilm and dimorphism assays. Auto-aggregation of C. albicans MYA-4901 and ALC2 was categorised as high, while the co-aggregation of the strains was low in the presence of K12. C. albicans total cell count decreased significantly when co-cultured with K12 compared with monocultured C. albicans biofilm (p 
    Matched MeSH terms: Biofilms
  7. Fulltext Efficiency of four Malaysian commercial disinfectants on removing Listeria monocytogenes biofilm
    Afsah-Hejri, L., Rukayadi, Y., Fouladynezhad, N., Son, R., Nakaguchi, Y., Nishibuchi, M.
    International Food Research Journal, 2013;20(3):1485-1490.
    MyJurnal
    Listeria monocytogenes (L. monocytogenes) is a gram positive food-borne pathogen that is able to form biofilm on food factory surfaces. Formation of biofilm makes the bacteria much more resistance to environmental stresses such as disinfectant. The extracellular polymeric matrix (biofilm structure) which is mostly comprised of sticky extracellular polysaccharides (EPS) and proteins can protect bacteria in a harsh condition. The efficiency of four disinfectants on removing L. monocytogenes biofilm was investigated. Five concentration levels (100, 50, 25, 12.5, and 6.25%) of disinfectants were tested. In the microtitre assay, the optical density at 595 nm CV-OD595 value, was used to measure the amount of remained biofilm after 24 h. Results showed that disinfectants did not have significant effect on removing L. monocytogenes biofilm. Formation of L. monocytogenes biofilm significantly decreased the efficiency of disinfectants. Biofilm produced by strain number 9 showed higher resistance to disinfectant. Low concentrations (
    Matched MeSH terms: Biofilms
  8. Antibacterial and anti-adherence effects of a plant extract mixture (PEM) and its individual constituent extracts (Psidium sp., Mangifera sp., and Mentha sp.) on single- and dual-species biofilms
    Shafiei Z, Haji Abdul Rahim Z, Philip K, Thurairajah N
    PeerJ, 2016;4:e2519.
    PMID: 27761322
    Plant extracts mixture (PEM) and its individual constituent plant extracts(Psidium sp., Mangifera sp., Mentha sp.) are known to have an anti-adhering effect towards oral bacteria in the single-species biofilm. To date, the adhering ability of the early and late plaque colonisers (Streptococcus sanguinis and Streptococcus mutans) to PEM-treated experimental pellicle have not been investigated in dual-species biofilms.
    Matched MeSH terms: Biofilms
  9. Fulltext Ime course detachment of biofilms in pipes by hydrochlorination
    Shanzay, A., Siddra, T. A., Warda, F., Sheeza, A., Maryam, A., Aina, S. Z., et al.
    Asian Journal of Medicine and Biomedicine, 2018;1(1):28-31.
    MyJurnal
    Bacterial biofilms are a complex community of microbes in which the cells are embedded in a polysaccharide matrix.
    This slime is a mean of protection in hostile environments. Biofilms in hospital settings are perilous as they not only
    make treatment difficult, cause blockage of pipes but are also cause of serious nosocomial infections thus making their
    dispersal an even more important phenomenon. Any foaming method is not applicable at all places for the cleaning of
    biofilms hence biofilm dispersal by household sweep containing hydrochloric acid was checked using the microliter
    plate assay as dispersal strategy. Bacteria from hospital waste disposal pipes were isolated, its ability to form biofilm
    was noted under different time intervals and then finally biofilm degradation was done using different concentrations
    of household sweep. It was noted that household sweep can be successfully employed at many places especially waste
    disposal pipes and acid resistant tubes. Our results indicated that 20% sweep (HCl conc. 1%) if used for only one
    minute can reduce the biofilms to 50%. Similarly increasing contact time can reduce the biofilms further.
    Matched MeSH terms: Biofilms
  10. Going Beyond Antibiotics: Natural Plant Extracts as an Emergent Strategy to Combat Biofilm-Associated Infections
    Kou J, Xin TY, McCarron P, Gupta G, Dureja H, Satija S, et al.
    J Environ Pathol Toxicol Oncol, 2020;39(2):125-136.
    PMID: 32749122 DOI: 10.1615/JEnvironPatholToxicolOncol.2020032665
    Biofilms are a collective of multiple types of bacteria that develop on a variety of surfaces. Biofilm development results in heightened resistance to antibiotics. Quorum sensing plays an important role in biofilm development as it is one of the common communication mechanisms within cells, which balances and stabilizes the environment, when the amount of bacteria increases. Because of the important implications of the roles biofilms play in infectious diseases, it is crucial to investigate natural antibacterial agents that are able to regulate biofilm formation and development. Various studies have suggested that natural plant products have the potential to suppress bacterial growth and exhibit chemopreventive traits in the modulation of biofilm development. In this review, we discuss and collate potential antibiofilm drugs and biological molecules from natural sources, along with their underlying mechanisms of action. In addition, we also discuss the antibiofilm drugs that are currently under clinical trials and highlight their potential future uses.
    Matched MeSH terms: Biofilms
  11. Nanoparticles approach to eradicate bacterial biofilm-related infections: A critical review
    Al-Wrafy FA, Al-Gheethi AA, Ponnusamy SK, Noman EA, Fattah SA
    Chemosphere, 2022 Feb;288(Pt 2):132603.
    PMID: 34678351 DOI: 10.1016/j.chemosphere.2021.132603
    Biofilm represents one of the crucial factors for the emergence of multi-drug resistance bacterial infections. The high mortality, morbidity and medical device-related infections are associated with biofilm formation, which requires primarily seek alternative treatment strategies. Recently, nanotechnology has emerged as a promising method for eradicating bacterial biofilm-related infection. The efficacy of nanoparticles (NPs) against bacterial infections interest great attention, and the researches on the subject are rapidly increasing. However, the majority of studies continue to focus on the antimicrobial effects of NPs in vitro, while only a few achieved in vivo and very few registered as clinical trials. The present review aimed to organize the scattered available information regarding NPs approach to eradicate bacterial biofilm-related infections. The current review highlighted the advantages and disadvantages associated with this approach, in addition to the challenges that prevent reaching the clinical applications. It was appeared that the production of NPs either as antimicrobials or as drug carriers requires further investigations to overcome the obstacles associated with their kinetic and biocompatibility.
    Matched MeSH terms: Biofilms
  12. Formulation of a Semisolid Emulsion Containing Leptospermum scoparium Essential Oil and Evaluation of In Vitro Antimicrobial and Antibiofilm Efficacy
    Porter GC, Safii SH, Medlicott NJ, Duncan WJ, Tompkins GR, Coates DE
    Planta Med, 2021 Mar;87(3):253-266.
    PMID: 33434939 DOI: 10.1055/a-1330-8765
    Manuka oil, an essential oil derived from the Leptospermum scoparium, has been traditionally used for wound care and as a topical antibacterial, antifungal, and anti-inflammatory. However, the essential oil is not well retained at mucosal sites, such as the oral cavity, where the benefits of the aforementioned properties could be utilized toward the treatment of persistent biofilms. Within this study, L. scoparium essential oil was incorporated into a semisolid emulsion for improved delivery. The safety profile of L. scoparium essential oil on human gingival fibroblasts was determined via cell viability, cytotoxicity, and caspase activation. The minimal bactericidal concentration of L. scoparium essential oil was determined, and the emulsion's antibiofilm effects visualized using confocal laser scanning microscopy. L. scoparium essential oil demonstrated a lower IC50 (0.02% at 48 h) when compared to the clinical control chlorhexidine (0.002% at 48 h) and displayed lower cumulative cytotoxicity. Higher concentrations of L. scoparium essential oil (≥ 0.1%) at 6 h resulted in higher caspase 3/7 activation, suggesting an apoptotic pathway of cell death. A minimal bactericidal concentration of 0.1% w/w was observed for 6 oral bacteria and 0.01% w/v for Porphyromonas gingivalis. Textural and rheometric analysis indicated increased stability of emulsion with a 1 : 3 ratio of L. scoparium essential oil: Oryza sativa carrier oil. The optimized 5% w/w L. scoparium essential oil emulsion showed increased bactericidal penetrative effects on Streptococci gordonii biofilms compared to oil alone and to chlorhexidine controls. This study has demonstrated the safety, formulation, and antimicrobial activity of L. scoparium essential oil emulsion for potential antibacterial applications at mucosal sites.
    Matched MeSH terms: Biofilms
  13. The performance of simultaneous partial nitritation, anammox, denitrification, and COD oxidation (SNADCO) method in the treatment of digested effluent of fish processing wastewater
    Sanjaya EH, Chen Y, Guo Y, Wu J, Chen H, Din MFM, et al.
    Bioresour Technol, 2022 Feb;346:126622.
    PMID: 34958906 DOI: 10.1016/j.biortech.2021.126622
    The simultaneous partial nitritation, anammox, denitrification, and COD oxidation (SNADCO) method was successfully carried out in an air-lift moving bed biofilm reactor (AL-MBBR) with cylinders carriers for the treatment of digested fish processing wastewater (FPW). Synthetic wastewater was used as substrate at stage 1. It changed into the digested FPW with dilution variation in order to increase the nitrogen and COD loading rates. With influent concentration of NH4+-N of 909 ± 101 mg-N/L and COD of 731 ± 26 mg/L, the nitrogen removal efficiency was 86.8% (nitrogen loading rate of 1.21 g-TN/L/d) and the COD removal efficiency was 50.5% (COD loading rate at 0.98 g-COD/L/d). This study showed that the process has the advantages in treating the real high ammonia concentration of digested wastewater containing organic compounds. The nitritation and anammox route was predominant in nitrogen removal, while COD oxidation and microbe proliferation played the main role in COD removal.
    Matched MeSH terms: Biofilms
  14. Fulltext In Vitro Assessment on Designing Novel Antibiofilms of Pseudomonas aeruginosa Using a Computational Approach
    Rachmawati D, Fahmi MZ, Abdjan MI, Wasito EB, Siswanto I, Mazlan N, et al.
    Molecules, 2022 Dec 15;27(24).
    PMID: 36558064 DOI: 10.3390/molecules27248935
    An anti-biofilm that can inhibit the matrix of biofilm formation is necessary to prevent recurrent and chronic Pseudomonas aeruginosa infection. This study aimed to design compounds with a new mechanism through competitive inhibitory activity against phosphomannomutase/phosphoglucomutase (PMM/PGM), using in vitro assessment and a computational (in silico) approach. The active site of PMM/PGM was assessed through molecular redocking using L-tartaric acid as the native ligand and other small molecules, such as glucaric acid, D-sorbitol, and ascorbic acid. The docking program set the small molecules to the active site, showing a stable complex formation. Analysis of structural similarity, bioavailability, absorption, distribution, metabolism, excretion, and toxicity properties proved the potential application of ligands as an anti-biofilm. In vitro assessment with crystal violet showed that the ligands could reach up to 95.87% inhibition at different concentrations. The nitrocellulose membrane and scanning electron microscopic visualization showed that the untreated P. aeruginosa biofilm was denser than the ligand-treated biofilm.
    Matched MeSH terms: Biofilms
  15. Influence of Fe2O3 and bacterial biofilms on Cu(II) distribution in a simulated aqueous solution: A feasibility study to sediments in the Pearl River Estuary (PR China)
    Kurniawan TA, Lo W, Othman MHD, Liang X, Goh HH, Chew KW
    J Environ Manage, 2023 Mar 01;329:117047.
    PMID: 36563449 DOI: 10.1016/j.jenvman.2022.117047
    This study investigated physico-chemical interactions among Cu(II), biogenic materials, and Fe2O3 in a continuous-flow biofilm reactor system under a well-controlled environment. The effects of Fe2O3 and bacterial biofilms on the distribution of Cu(II) in a simulated aquatic environment were studied. To control biological and abiotic elements in the marine environment, a biofilm reactor was designed to understand the metal speciation of Cu(II) and its distribution. The reactor consisted of a biofilm chamber equipped with glass slides for biofilms attachment. Due to its ability to grow as biofilm in the medium, Pseudomonas atlantica was cultivated to adsorb trace Cu(II) to attached and suspended cells. It was found that biofilms with 170-285 mequiv chemical oxygen demand (COD) concentration/m2 of total oxidizable materials accelerated the Cu(II) adsorption to the surface of the reactor significantly by a factor of five. A significant inhibition to the bacterial growth took place (p ≤ 0.05; t-test) when Cu(II) concentration was higher than 0.5 mg/L. In the absence of Cu(II), bacterial cells grew normally to 0.075 of optical density (OD). However, at the Cu(II) concentration of 0.2 mg/L, the cells grew to a lower OD of 0.58. The presence of glycine and EDTA substantially reduced the toxicity of Cu(II) on bacterial growth (p ≤ 0.05; paired t-test). Their complexation with Cu(II) rendered the metal ions less available to bacterial cells. This implies that the Fe2O3 and bacterial biofilm affected Cu(II) distribution and speciation in the aquatic environment.
    Matched MeSH terms: Biofilms
  16. Mechanistic behaviour of Chlorella vulgaris biofilm formation onto waste organic solid support used to treat palm kernel expeller in the recent Anthropocene
    Rawindran H, Syed R, Alangari A, Khoo KS, Lim JW, Sahrin NT, et al.
    Environ Res, 2023 Apr 01;222:115352.
    PMID: 36716802 DOI: 10.1016/j.envres.2023.115352
    The capacity to maximize the proliferation of microalgal cells by means of topologically textured organic solid surfaces under various pH gave rise to the fundamental biophysical analysis of cell-surface attachment in this study. The substrate used in analysis was palm kernel expeller (PKE) in which the microalgal cells had adhered onto its surface. The findings elucidated the relevance of surface properties in terms of surface wettability and surface energy in relation to the attached microalgal growth with pH as the limiting factor. The increase in hydrophobicity of PKE-microalgae attachment was able to facilitate the formation of biofilm better. The pH 5 and pH 11 were found to be the conditions with highest and lowest microalgal growths, respectively, which were in tandem with the highest contact angle value at pH 5 and conversely for pH 11. The work of attachment (Wcs) had supported the derived model with positive values being attained for all the pH conditions, corroborating the thermodynamic feasibility. Finally, this study had unveiled the mechanism of microalgal attachment onto the surface of PKE using the aid of extracellular polymeric surfaces (EPS) from microalgae. Also, the hydrophobic nature of PKE enabled excellent attachment alongside with nutrients for microalgae to grow and from layer-by-layer (LbL) assembly. This assembly was then isolated using organosolv method by means of biphasic solvents, namely, methanol and chloroform, to induce detachment.
    Matched MeSH terms: Biofilms
  17. Antifungal susceptibility profile and biofilm-producing capability of Candida tropicalis isolates in a tertiary medical centre
    Navarathinam SD, Neoh HM, Tan TL, Wahab AA, Mohd Nizam Tzar MN, Ding CH
    Malays J Pathol, 2023 Dec;45(3):417-424.
    PMID: 38155383
    BACKGROUND: Candida tropicalis is a globally distributed yeast that has been popping up in the medical literature lately, albeit for unenviable reasons. C. tropicalis is associated with substantial morbidity, mortality as well as drug resistance. The aims of this study were to ascertain the antifungal susceptibility profile and the biofilm-producing capability of this notorious yeast in our centre.

    METHODS: C. tropicalis isolates from sterile specimens were collected over a 12-month period. Conclusive identification was achieved biochemically with the ID 32 C kit. Susceptibility to nine antifungal agents was carried out using the colourimetric broth microdilution kit Sensititre YeastOne YO10. Biofilm-producing capability was evaluated by quantifying biomass formation spectrophotometrically following staining with crystal violet.

    RESULTS: Twenty-four non-repetitive isolates of C. tropicalis were collected. The resistance rates to the triazole agents were 29.2% for fluconazole, 16.7% for itraconazole, 20.8% for voriconazole and 8.3% for posaconazole-the pan-azole resistance rate was identical to that of posaconazole. No resistance was recorded for amphotericin B, flucysosine or any of the echinocandins tested. A total of 16/24 (66.7%) isolates were categorized as high biomass producers and 8/24 (33.3%) were moderate biomass producers. None of our isolates were low biomass producers.

    CONCLUSION: The C. tropicalis isolates from our centre were resistant only to triazole agents, with the highest resistance rate being recorded for fluconazole and the lowest for posaconazole. While this is not by itself alarming, the fact that our isolates were prolific biofilm producers means that even azole-susceptible isolates can be paradoxically refractory to antifungal therapy.

    Matched MeSH terms: Biofilms
  18. Fulltext Scaling up of dual-chamber microbial electrochemical systems - An appraisal using systems design approach
    Fathima A, Ilankoon IMSK, Zhang Y, Chong MN
    Sci Total Environ, 2024 Feb 20;912:169186.
    PMID: 38086487 DOI: 10.1016/j.scitotenv.2023.169186
    Impetus to minimise the energy and carbon footprints of evolving wastewater resource recovery facilities has promoted the development of microbial electrochemical systems (MES) as an emerging energy-neutral and sustainable platform technology. Using separators in dual-chamber MES to isolate anodic and cathodic environments creates endless opportunities for its myriad applications. Nevertheless, the high internal resistance and the complex interdependencies among various system factors have challenged its scale-up. This critical review employed a systems approach to examine the complex interdependencies and practical issues surrounding the implementation and scalability of dual-chamber MES, where the anodic and cathodic reactions are mutually appraised to improve the overall system efficiency. The robustness and stability of anodic biofilms in large-volume MES is dependent on its inoculum source, antecedent history and enrichment strategies. The composition and anode-respiring activity of these biofilms are modulated by the anolyte composition, while their performance demands a delicate balance between the electrode size, macrostructure and the availability of substrates, buffers and nutrients when using real wastewater as anolyte. Additionally, the catholyte governed the reduction environment and associated energy consumption of MES with scalable electrocatalysts needed to enhance the sluggish reaction kinetics for energy-efficient resource recovery. A comprehensive assessment of the dual-chamber reactor configuration revealed that the tubular, spiral-wound, or plug-in modular MES configurations are suitable for pilot-scale, where it could be designed more effectively using efficient electrode macrostructure, suitable membranes and bespoke strategies for continuous operation to maximise their performance. It is anticipated that the critical and analytical understanding gained through this review will support the continuous development and scaling-up of dual-chamber MES for prospective energy-neutral treatment of wastewater and simultaneous circular management of highly relevant environmental resources.
    Matched MeSH terms: Biofilms
  19. In vitro activity of xanthorrhizol isolated from the rhizome of Javanese turmeric (Curcuma xanthorrhiza Roxb.) against Candida albicans biofilms
    Rukayadi Y, Hwang JK
    Phytother Res, 2013 Jul;27(7):1061-6.
    PMID: 22969012 DOI: 10.1002/ptr.4834
    The purpose of this study was to investigate the activity of xanthorrhizol isolated from Curcuma xanthorrhiza Roxb. on Candida albicans biofilms at adherent, intermediate, and mature phase of growth. C. albicans biofilms were formed in flat-bottom 96-well microtiter plates. The biofilms of C. albicans at different phases of development were exposed to xanthorrhizol at different concentrations (0.5 µg/mL-256 µg/mL) for 24 h. The metabolic activity of cells within the biofilms was quantified using the XTT reduction assay. Sessile minimum inhibitory concentrations (SMICs) were determined at 50% and 80% reduction in the biofilm OD₄₉₀ compared to the control wells. The SMIC₅₀ and SMIC₈₀ of xanthorrhizol against 18 C. albicans biofilms were 4--16 µg/mL and 8--32 µg/mL, respectively. The results demonstrated that the activity of xanthorrhizol in reducing C. albicans biofilms OD₄₉₀ was dependent on the concentration and the phase of growth of biofilm. Xanthorrhizol at concentration of 8 µg/mL completely reduced in biofilm referring to XTT-colorimetric readings at adherent phase, whereas 32 µg/mL of xanthorrhizol reduced 87.95% and 67.48 % of biofilm referring to XTT-colorimetric readings at intermediate and mature phases, respectively. Xanthorrhizol displayed potent activity against C. albicans biofilms in vitro and therefore might have potential therapeutic implication for biofilm-associated candidal infections.
    Matched MeSH terms: Biofilms/drug effects*; Biofilms/growth & development
  20. Application of Phenotype Microarray for Profiling Carbon Sources Utilization between Biofilm and Non-Biofilm of Pseudomonas aeruginosa from Clinical Isolates
    Ismail NS, Subbiah SK, Taib NM
    Curr Pharm Biotechnol, 2020;21(14):1539-1550.
    PMID: 32598252 DOI: 10.2174/1389201021666200629145217
    BACKGROUND: This is the fastest work in obtaining the metabolic profiles of Pseudomonas aeruginosa in order to combat the infection diseases which leads to high morbidity and mortality rates. Pseudomonas aeruginosa is a high versatility of gram-negative bacteria that can undergo aerobic and anaerobic respiration. Capabilities in deploying different carbon sources, energy metabolism and regulatory system, ensure the survival of this microorganism in the diverse environment condition. Determination of differences in carbon sources utilization among biofilm and non-biofilm of Pseudomonas aeruginosa provides a platform in understanding the metabolic activity of the microorganism.

    METHODS: The study was carried out from September 2017 to February 2019. Four archive isolates forming strong and intermediate biofilm and non-biofilms producer were subcultured from archive isolates. ATCC 27853 P. aeruginosa was used as a negative control or non-biofilm producing microorganism. Biofilm formation was confirmed by Crystal Violet Assay (CVA) and Congo Red Agar (CRA). Metabolic profiles of the biofilm and non-biofilms isolates were determined by phenotype microarrays (Biolog Omnilog).

    RESULTS AND DISCUSSION: In this study, Pseudomonas aeruginosa biofilm isolates utilized uridine, L-threonine and L-serine while non-biofilm utilized adenosine, inosine, monomethyl, sorbic acid and succinamic acid.

    CONCLUSION: The outcome of this result will be used for future studies to improve detection or inhibit the growth of P. aeruginosa biofilm and non-biofilm respectively.

    Matched MeSH terms: Biofilms/drug effects; Biofilms/growth & development*
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