共查询到20条相似文献,搜索用时 531 毫秒
1.
A. Nur K. Hirota H. Yumoto K. Hirao D. Liu K. Takahashi K. Murakami T. Matsuo R. Shu Y. Miyake 《Journal of applied microbiology》2013,115(1):260-270
Aims
The aim of this study was to clarify the effects of homologous and heterologous extracellular DNAs (eDNAs) and histone‐like DNA‐binding protein (HLP) on Streptococcus intermedius biofilm development and rigidity.Methods and Results
Formed biofilm mass was measured with 0·1% crystal violet staining method and observed with a scanning electron microscope. The localizations of eDNA and extracellular HLP (eHLP) in formed biofilm were detected by staining with 7‐hydoxyl‐9H‐(1,3‐dichloro‐9,9‐dimethylacridin‐2‐one) and anti‐HLP antibody without fixation, respectively. DNase I treatment (200 U ml?1) markedly decreased biofilm formation and cell density in biofilms. Colocalization of eHLP and eDNA in biofilm was confirmed. The addition of eDNA (up to 1 μg ml?1) purified from Strep. intermedius, other Gram‐positive bacteria, Gram‐negative bacteria, or human KB cells into the Strep. intermedius culture increased the biofilm mass of all tested strains of Strep. intermedius, wild‐type, HLP‐downregulated strain and control strains. In contrast, the addition of eDNA (>1 μg ml?1) decreased the biofilm mass of all Strep. intermedius strains.Conclusions
These findings demonstrated that eDNA and eHLP play crucial roles in biofilm development and its rigidity.Significance and Impact of the Study
eDNA‐ and HLP‐targeting strategies may be applicable to novel treatments for bacterial biofilm‐related infectious diseases. 相似文献2.
Hideo Yonezawa Takako Osaki Satoshi Kurata Minoru Fukuda Hayato Kawakami Kuniyasu Ochiai Tomoko Hanawa Shigeru Kamiya 《BMC microbiology》2009,9(1):197
Background
Helicobacter pylori forms biofilms on glass surfaces at the air-liquid interface in in vitro batch cultures; however, biofilms of H. pylori have not been well characterized. In the present study, we analyzed the ability of H. pylori strains to form biofilms and characterized the underlying mechanisms of H. pylori biofilm formation. 相似文献3.
Trevor R Zuroff Hans Bernstein Jenna Lloyd-Randolfi Lourdes Jimenez-Taracido Philip S Stewart Ross P Carlson 《BMC microbiology》2010,10(1):185
Background
Biofilms are ubiquitous. For instance, the majority of medical infections are thought to involve biofilms. However even after decades of investigation, the in vivo efficacy of many antimicrobial strategies is still debated suggesting there is a need for better understanding of biofilm antimicrobial tolerances. The current study's goal is to characterize the robustness of biofilm antibiotic tolerance to medically and industrially relevant culturing perturbations. By definition, robust systems will return similar, predictable responses when perturbed while non-robust systems will return very different and potentially unpredictable responses. The predictability of an antibiotic tolerance response is essential to developing, testing, and employing antimicrobial strategies. 相似文献4.
This study was performed in order to characterize the relationship between adhesion and biofilm formation abilities of drinking
water-isolated bacteria (Acinetobacter calcoaceticus, Burkholderia cepacia, Methylobacterium sp., Mycobacterium mucogenicum, Sphingomonas capsulata and Staphylococcus sp.). Adhesion was assessed by two distinct methods: thermodynamic prediction of adhesion potential by quantifying hydrophobicity
and the free energy of adhesion; and by microtiter plate assays. Biofilms were developed in microtiter plates for 24, 48 and
72 h. Polystyrene (PS) was used as adhesion substratum. The tested bacteria had negative surface charge and were hydrophilic.
PS had negative surface charge and was hydrophobic. The free energy of adhesion between the bacteria and PS was > 0 mJ/m2 (thermodynamic unfavorable adhesion). The thermodynamic approach was inappropriate for modelling adhesion of the tested drinking
water bacteria, underestimating adhesion to PS. Only three (B. cepacia, Sph. capsulata and Staphylococcus sp.) of the six bacteria were non-adherent to PS. A. calcoaceticus, Methylobacterium sp. and M. mucogenicum were weakly adherent. This adhesion ability was correlated with the biofilm formation ability when comparing with the results
of 24 h aged biofilms. Methylobacterium sp. and M. mucogenicum formed large biofilm amounts, regardless the biofilm age. Given time, all the bacteria formed biofilms; even those non-adherents
produced large amounts of matured (72 h aged) biofilms. The overall results indicate that initial adhesion did not predict
the ability of the tested drinking water-isolated bacteria to form a mature biofilm, suggesting that other events such as
phenotypic and genetic switching during biofilm development and the production of extracellular polymeric substances (EPS),
may play a significant role on biofilm formation and differentiation. This understanding of the relationship between adhesion
and biofilm formation is important for the development of control strategies efficient in the early stages of biofilm development. 相似文献
5.
Background
Pseudomonas fluorescens is an important food spoilage organism, usually found in the form of biofilms. Bacterial biofilms are inherently resistant to a variety of antimicrobial agents, therefore alternative methods to biofilm control, such as bacteriophages (phages) have been suggested. Phage behavior on biofilms is still poorly investigated and needs further understanding. Here we describe the application of phage ϕIBB-PF7, a newly isolated phage, to control P. fluorescens biofilms. The biofilms were formed under static or dynamic conditions and with or without renewal of medium. 相似文献6.
Aims: To investigate the structural organization and dynamics of exopolysaccharides (EPS) matrix and microcolonies formation by Streptococcus mutans during the biofilm development process. Methods and Results: Biofilms of Strep. mutans were formed on saliva‐coated hydroxyapatite (sHA) discs in the presence of glucose or sucrose (alone or mixed with starch). At specific time points, biofilms were subjected to confocal fluorescence imaging and computational analysis. EPS matrix was steadily formed on sHA surface in the presence of sucrose during the first 8 h followed by a threefold biomass increase between 8 and 30 h of biofilm development. The initial formation and further development of three‐dimensional microcolony structure occurred concomitantly with EPS matrix synthesis. Tridimensional renderings showed EPS closely associated with microcolonies throughout the biofilm development process forming four distinct domains (i) between sHA surface and microcolonies, (ii) within, (iii) covering and (iv) filling the spaces between microcolonies. The combination of starch and sucrose resulted in rapid formation of elevated amounts of EPS matrix and faster assembly of microcolonies by Strep. mutans, which altered their structural organization and susceptibility of the biofilm to acid killing (vs sucrose‐grown biofilms; P < 0·05). Conclusions: Our data indicate that EPS modulate the development, sequence of assembly and spatial distribution of microcolonies by Strep. mutans. Significance and Impact of the Study: Simultaneous visualization and analysis of EPS matrix and microcolonies provide a more precise examination of the structural organization of biofilms than labelling bacteria alone, which could be a useful approach to elucidate the exact mechanisms by which Strep. mutans influences oral biofilm formation and possibly identify novel targets for effective antibiofilm therapies. 相似文献
7.
Moshe Shemesh Avshalom Tam Miriam Kott-Gutkowski Mark Feldman Doron Steinberg 《BMC microbiology》2008,8(1):236
Background
A biofilm is a complex community of microorganisms that develop on surfaces in diverse environments. The thickness of the biofilm plays a crucial role in the physiology of the immobilized bacteria. The most cariogenic bacteria, mutans streptococci, are common inhabitants of a dental biofilm community. In this study, DNA-microarray analysis was used to identify differentially expressed genes associated with the thickness of S. mutans biofilms. 相似文献8.
Sander Croes Ruud H Deurenberg Marie-Louise L Boumans Patrick S Beisser Cees Neef Ellen E Stobberingh 《BMC microbiology》2009,9(1):229
Background
Since bacteria embedded in biofilms are far more difficult to eradicate than planktonic infections, it would be useful to know whether certain Staphylococcus aureus lineages are especially involved in strong biofilm formation. For this reason, in vitro biofilm formation of 228 clinical S. aureus isolates of distinct clonal lineages was investigated. 相似文献9.
Background
Pseudomonas aeruginosa is a common pathogen in chronic respiratory tract infections. It typically makes a biofilm, which makes treatment of these infections difficult. In this study, we investigated the inhibitory effects of N-acetylcysteine (NAC) on biofilms produced by P. aeruginosa. 相似文献10.
Heleen Nailis Tom Coenye Filip Van Nieuwerburgh Dieter Deforce Hans J Nelis 《BMC molecular biology》2006,7(1):25-9
Background
Candida albicans biofilms are commonly found on indwelling medical devices. However, the molecular basis of biofilm formation and development is not completely understood. Expression analysis of genes potentially involved in these processes, such as the ALS (Agglutinine Like Sequence) gene family can be performed using quantitative PCR (qPCR). In the present study, we investigated the expression stability of eight housekeeping genes potentially useful as reference genes to study gene expression in Candida albicans (C. albicans) biofilms, using the geNorm Visual Basic Application (VBA) for Microsoft Excel. To validate our normalization strategies we determined differences in ALS1 and ALS3 expression levels between C. albicans biofilm cells and their planktonic counterparts. 相似文献11.
Zhao GQ Ye LH Huang YC Yang DK Li L Xu G Lei YJ 《Cell biochemistry and biophysics》2011,61(2):371-376
The aim of the study was to establish an in vitro model of Staphylococcus epidermidis biofilms on polyvinyl chloride (PVC) material, and to investigate bacterial biofilm formation and its structure using the
combined approach of confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM). Staphylococcus epidermidis bacteria (stain RP62A) were incubated with PVC pieces in Tris buffered saline to form biofilms. Biofilm formation was examined
at 6, 12, 18, 24, 30, and 48 h. Thicknesses of these biofilms and the number, and percentage of viable cells in biofilms were
measured. CT scan images of biofilms were obtained using CLSM and environmental SEM. The results of this study showed that
Staphylococcus epidermidis biofilm is a highly organized multi-cellular structure. The biofilm is constituted of large number of viable and dead bacterial
cells. Bacterial biofilm formation on the surface of PVC material was found to be a dynamic process with maximal thickness
being attained at 12–18 h. These biofilms became mature by 24 h. There was significant difference in the percentage of viable
cells along with interior, middle, and outer layers of biofilms (P < 0.05). Staphylococcus epidermidis biofilm is sophisticated in structure and the combination method involving CLSM and SEM was ideal for investigation of biofilms
on PVC material. 相似文献
12.
Background
Adhesion and successful colonization of bacteria onto solid surfaces play a key role in biofilm formation. The initial adhesion and the colonization of bacteria may differ between the various types of surfaces found in oral cavity. Therefore, it is conceivable that diverse biofilms are developed on those various surfaces. The aim of the study was to investigate the molecular modifications occurring during in vitro biofilm development of Streptococcus mutans UA159 on several different dental surfaces. 相似文献13.
Sound Waves Effectively Assist Tobramycin in Elimination of Pseudomonas aeruginosa Biofilms In vitro
H. M. H. N. Bandara A. Harb D. Kolacny Jr. P. Martins H. D. C. Smyth 《AAPS PharmSciTech》2014,15(6):1644-1654
Microbial biofilms are highly refractory to antimicrobials. The aim of this study was to investigate the use of low-frequency vibration therapy (20–20 kHz) on antibiotic-mediated Pseudomonas aeruginosa biofilm eradication. In screening studies, low-frequency vibrations were applied on model biofilm compositions to identify conditions in which surface standing waves were observed. Alginate surface tension and viscosity were also measured. The effect of vibration on P. aeruginosa biofilms was studied using a standard biofilm assay. Subminimal inhibitory concentrations (sub-MIC) of tobramycin (5 μg/ml) were added to biofilms 3 h prior, during, and immediately after vibration and quantitatively assessed by (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) reduction assay (XTT) and, qualitatively, by confocal laser scanning microscopy (CLSM). The standing waves occurred at frequencies <1,000 Hz. Biofilms vibrated without sub-MIC tobramycin showed a significantly reduced metabolism compared to untreated controls (p < 0.05). Biofilms treated with tobramycin and vibrated simultaneously (450, 530, 610, and 650 Hz), or vibrated (450 and 650 Hz) then treated with tobramycin subsequently, or vibrated (610Hz, 650Hz) after 3 h of tobramycin treatment showed significantly lower metabolism compared to P. aeruginosa biofilm treated with tobramycin alone (p < 0.05). CLSM imaging further confirmed these findings. Low frequency vibrations assisted tobramycin in killing P. aeruginosa biofilms at sub-MIC. Thus, sound waves together with antibiotics are a promising approach in eliminating pathogenic biofilms.KEY WORDS: alginate, biofilm, Pseudomonas, tobramycin, vibration 相似文献
14.
15.
Kristina Jonas Henrik Tomenius Abdul Kader Staffan Normark Ute Römling Lyubov M Belova Öjar Melefors 《BMC microbiology》2007,7(1):70
Background
Curli, cellulose and the cell surface protein BapA are matrix components in Salmonella biofilms. In this study we have investigated the roles of these components for the morphology of bacteria grown as colonies on agar plates and within a biofilm on submerged mica surfaces by applying atomic force microscopy (AFM) and light microscopy. 相似文献16.
Adnane Sellam Thamir Al-Niemi Kathleen McInnerney Susan Brumfield Andre Nantel Peter A Suci 《BMC microbiology》2009,9(1):25-22
Background
Dispersal from Candida albicans biofilms that colonize catheters is implicated as a primary factor in the link between contaminated catheters and life threatening blood stream infections (BSI). Appropriate in vitro C. albicans biofilm models are needed to probe factors that induce detachment events. 相似文献17.
Ye Zhang Hanieh Gholizadeh Paul Young Daniela Traini Ming Li Hui Xin Ong Shaokoon Cheng 《Biotechnology and bioengineering》2023,120(3):702-714
Biofilms are communities of bacterial cells encased in a self-produced polymeric matrix that exhibit high tolerance toward environmental stress. Despite the plethora of research on biofilms, most P. aeruginosa biofilm models are cultured on a solid–liquid interface, and the longitudinal growth characteristics of P. aeruginosa biofilm are unclear. This study demonstrates the real-time and noninvasive monitoring of biofilm growth using a novel dual-chamber microfluidic device integrated with electrochemical detection capabilities to monitor pyocyanin (PYO). The growth of P. aeruginosa biofilms on the air–liquid interface (ALI) was monitored over 48 h, and its antibiotic susceptibility to 6 h exposure of 50, 400, and 1600 µg/ml of ciprofloxacin solutions was analyzed. The biofilm was treated directly on its surface and indirectly from the substratum by delivering the CIP solution to the top or bottom chamber of the microfluidic device. Results showed that P. aeruginosa biofilm developed on ALI produces PYO continuously, with the PYO production rate varying longitudinally and peak production observed between 24 and 30 h. In addition, this current study shows that the amount of PYO produced by the ALI biofilm is proportional to its viable cell numbers, which has not been previously demonstrated. Biofilm treated with ciprofloxacin solution above 400 µg/ml showed significant PYO reduction, with biofilms being killed more effectively when treatment was applied to their surfaces. The electrochemical measurement results have been verified with colony-forming unit count results, and the strong correlation between the PYO electrical signal and the viable cell number highlights the usefulness of this approach for fast and low-cost ALI biofilm study and antimicrobial tests. 相似文献
18.
Arnold JW 《Journal of industrial microbiology & biotechnology》2008,35(11):1475-1480
Controlling bacterial biofilms is necessary for food safety and industrial processing in clean room environments. Our goal
was to develop a method to quantitatively measure biofilm produced by pathogens under wet poultry production and processing
conditions. Stainless steel and glass coupons were incubated in aqueous media containing reduced nutrients and exposed to
Listeria monocytogenes under static temperature and humidity conditions. Samples were measured separately by biofilm assay and viable cell density,
and then confirmed by spectrophotometry and microscopy. The biofilm assay resulted in different t groupings from the cell density. The mean from the biofilm assay was 0.50, and the error% was 0.595. The mean of the log10 density (cfu/cm2) was 5.90, and the standard deviation ranged from 0.127 to 0.438 on 24 coupons. The typical sequence of biofilm development,
followed by microscopy of biofilm grown on glass coupons, exhibited a change from dispersed single cells to an all-over pattern
of clumps with few dispersed cells. L. monocytogenes formed biofilms on all of the substrata tested. Bacterial counts from planktonic cultures at 24, 48, 72, and 144 h confirmed
that L. monocytogenes remained viable throughout the experiment and reached equilibrium between 6 and 24 h. The cell density log10/ml was 8.01, 8.03, 7.69, and 6.66, respectively; and the standard deviation ranged from 0.156 to 0.394. The data will be
used to grow stable biofilms of Listeria spp. collected from the food processing environment for further study. This is the first use of the crystal violet assay
for measurement of bacterial biofilms on stainless steel under these conditions. The methods tested are applicable to other
bacteria and substrata. 相似文献
19.
Biofilm and capsule formation of the diatom Achnanthidium minutissimum are affected by a bacterium 下载免费PDF全文
Photoautotrophic biofilms play an important role in various aquatic habitats and are composed of prokaryotic and/or eukaryotic organisms embedded in extracellular polymeric substances (EPS). We have isolated diatoms as well as bacteria from freshwater biofilms to study organismal interactions between representative isolates. We found that bacteria have a strong impact on the biofilm formation of the pennate diatom Achnanthidium minutissimum. This alga produces extracellular capsules of insoluble EPS, mostly carbohydrates (CHO), only in the presence of bacteria (xenic culture). The EPS themselves also have a strong impact on the aggregation and attachment of the algae. In the absence of bacteria (axenic culture), A. minutissimum did not form capsules and the cells grew completely suspended. Fractionation and quantification of CHO revealed that the diatom in axenic culture produces large amounts of soluble CHO, whereas in the xenic culture mainly insoluble CHO were detected. For investigation of biofilm formation by A. minutissimum, a bioassay was established using a diatom satellite Bacteroidetes bacterium that had been shown to induce capsule formation of A. minutissimum. Interestingly, capsule and biofilm induction can be achieved by addition of bacterial spent medium, indicating that soluble hydrophobic molecules produced by the bacterium may mediate the diatom/bacteria interaction. With the designed bioassay, a reliable tool is now available to study the chemical interactions between diatoms and bacteria with consequences for biofilm formation. 相似文献
20.
Heleen Nailis Soňa Kucharíková Markéta Řičicová Patrick Van Dijck Dieter Deforce Hans Nelis Tom Coenye 《BMC microbiology》2010,10(1):114