Real-time PCR analysis of Vibrio vulnificus from oysters.
AuthorsCampbell MS, Wright AC
JournalAppl Environ Microbiol
PubMed ID14660359
Vibrio vulnificus is an opportunistic human pathogen commonly found in estuarine environments. Infections are associated with raw oyster consumption and can produce rapidly fatal septicemia in susceptible individuals. Standard enumeration of this organism in shellfish or seawater is laborious and inaccurate; therefore, more efficient assays are needed. An oligonucleotide probe ... More
Ethidium monoazide for DNA-based differentiation of viable and dead bacteria by 5'-nuclease PCR.
AuthorsNogva HK, Drømtorp SM, Nissen H, Rudi K
JournalBiotechniques
PubMed ID12703305
'PCR techniques have significantly improved the detection and identification of bacterial pathogens. Even so, the lack of differentiation between DNA from viable and dead cells is one of the major challenges for diagnostic DNA-based methods. Certain nucleic acid-binding dyes can selectively enter dead bacteria and subsequently be covalently linked to ... More
Escherichia coli cells with increased levels of DnaA and deficient in recombinational repair have decreased viability.
'The dnaA operon of Escherichia coli contains the genes dnaA, dnaN, and recF encoding DnaA, beta clamp of DNA polymerase III holoenzyme, and RecF. When the DnaA concentration is raised, an increase in the number of DNA replication initiation events but a reduction in replication fork velocity occurs. Because DnaA ... More
Substratum topography influences susceptibility of Salmonella enteritidis biofilms to trisodium phosphate.
AuthorsKorber DR, Choi A, Wolfaardt GM, Ingham SC, Caldwell DE
JournalAppl Environ Microbiol
PubMed ID9292984
'Established (48- and 72-h) Salmonella enteritidis biofilms grown in glass flow cells with or without artificial crevices (0.5-, 0.3-, and 0.15-mm widths) were subjected to a 10% trisodium phosphate (TSP) solution under different flow regimens (0.3, 0.6, 1.2, and 1.8 cm s-1). The abundance of biofilm remaining after TSP treatment, ... More
Phagosomal maturation and intracellular survival of Mycobacterium avium subspecies paratuberculosis in J774 cells.
AuthorsHostetter J, Steadham E, Haynes J, Bailey T, Cheville N
JournalComp Immunol Microbiol Infect Dis
PubMed ID12676127
'The mechanisms by which Mycobacterium avium subspecies paratuberculosis (M. a. ptb) survives within macrophages are not well characterized. One strategy for intracellular survival developed by Mycobacterium tuberculosis is inhibition of phagosomal maturation. In this study it was hypothesized that M. a. ptb is capable of survival within macrophages by residing ... More
Combination of immunosensor detection with viability testing and confirmation using the polymerase chain reaction and culture.
AuthorsJohnson-White B, Lin B, Ligler FS
JournalAnal Chem
PubMed ID17194131
'Rapid and accurate differential determination of viable versus nonviable microbes is critical for formulation of an appropriate response after pathogen detection. Sensors for rapid bacterial identification can be used for applications ranging from environmental monitoring and homeland defense to food process monitoring, but few provide viability information. This study combines ... More
Effect of acid stress on the physiology of biofilm cells of Streptococcus mutans.
AuthorsMcNeill K, Hamilton IR,
JournalMicrobiology
PubMed ID14993323
'Streptococcus mutans is a component of the dental plaque biofilm and an important aetiological agent in dental caries. Although this organism growing in the suspended (planktonic) state has been well characterized, relatively little is known about its physiology in biofilms, particularly in the acidic environments associated with caries development. The ... More
Analysis of molecular diffusion in ftsK cell-division mutants using laser surgery.
AuthorsGoksör M, Diez A, Enger J, Hanstorp D, Nyström T
JournalEMBO Rep
PubMed ID12947413
'Escherichia coli cells that lack the carboxy-terminal part of FtsK fail to segregate their chromosomes properly during cytokinesis and tend to form chains. These chains are possibly formed as a result of DNA being trapped in the division planes or a failure to fuse the membrane during septum formation. If ... More
Survival of FimH-expressing enterobacteria in macrophages relies on glycolipid traffic.
AuthorsBaorto DM, Gao Z, Malaviya R, Dustin ML, van der Merwe A, Lublin DM, Abraham SN
JournalNature
PubMed ID9335508
'Strains of Escherichia coli persist within the human gut as normal commensals, but are frequent pathogens and can cause recurrent infection. Here we show that, in contrast to E. coli subjected to opsonic interactions stimulated by the host''s immune response, E. coli that bind to the macrophage surface exclusively through ... More
Identity and effects of quorum-sensing inhibitors produced by Penicillium species.
AuthorsRasmussen TB, Skindersoe ME, Bjarnsholt T, Phipps RK, Christensen KB, Jensen PO, Andersen JB, Koch B, Larsen TO, Hentzer M, Eberl L, Hoiby N, Givskov M,
JournalMicrobiology
PubMed ID15870443
'Quorum sensing (QS) communication systems are thought to afford bacteria with a mechanism to strategically cause disease. One example is Pseudomonas aeruginosa, which infects immunocompromised individuals such as cystic fibrosis patients. The authors have previously documented that blockage of the QS systems not only attenuates Ps. aeruginosa but also renders ... More
The role of polyhydroxyalkanoate biosynthesis by Pseudomonas aeruginosa in rhamnolipid and alginate production as well as stress tolerance and biofilm formation.
AuthorsPham TH, Webb JS, Rehm BH,
JournalMicrobiology
PubMed ID15470118
'Pseudomonas aeruginosa is capable of synthesizing polyhydroxyalkanoic acids (PHAs) and rhamnolipids, both of which are composed of 3-hydroxydecanoic acids connected by ester bonds, as well as synthesizing the biofilm matrix polymer alginate. In order to study the influence of PHA biosynthesis on rhamnolipid and alginate biosynthesis, as well as stress ... More
Catheter lock solutions influence staphylococcal biofilm formation on abiotic surfaces.
'BACKGROUND: Microbial biofilms form on central venous catheters and may be associated with systemic infections as well as decreased dialysis efficiency due to catheter thrombosis. The most widely used anticoagulant catheter lock solution in the US is sodium heparin. We have previously shown that sodium heparin in clinically relevant concentrations ... More
Mechanisms of killing of Bacillus subtilis spores by hypochlorite and chlorine dioxide.
AuthorsYoung SB, Setlow P
JournalJ Appl Microbiol
PubMed ID12807454
'AIMS: To determine the mechanisms of Bacillus subtilis spore killing by hypochlorite and chlorine dioxide, and its resistance against them. METHODS AND RESULTS: Spores of B. subtilis treated with hypochlorite or chlorine dioxide did not accumulate damage to their DNA, as spores with or without the two major DNA protective ... More
Detection of bacterial contamination in starch and resin-based papermaking chemicals using fluorescence techniques.
AuthorsNohynek L, Saski E, Haikara A, Raaska L
JournalJ Ind Microbiol Biotechnol
PubMed ID12720090
'Rapid fluorescence techniques were evaluated for the detection of bacterial contaminants in papermaking chemicals including starch and the resin-based sizes and starch slurries used in the paper industry. Viable and non-viable bacterial cells were visualised by fluorescent probes and detected by epifluorescence microscopy and flow cytometry. The best discrimination ability ... More
Direct in situ viability assessment of bacteria in probiotic dairy products using viability staining in conjunction with confocal scanning laser microscopy.
AuthorsAuty MA, Gardiner GE, McBrearty SJ, O'Sullivan EO, Mulvihill DM, Collins JK, Fitzgerald GF, Stanton C, Ross RP
JournalAppl Environ Microbiol
PubMed ID11133474
'The viability of the human probiotic strains Lactobacillus paracasei NFBC 338 and Bifidobacterium sp. strain UCC 35612 in reconstituted skim milk was assessed by confocal scanning laser microscopy using the LIVE/DEAD BacLight viability stain. The technique was rapid (<30 min) and clearly differentiated live from heat-killed bacteria. The microscopic enumeration ... More
Starvation of Flavobacterium psychrophilum in broth, stream water and distilled water.
AuthorsVatsos IN, Thompson KD, Adams A
JournalDis Aquat Organ
PubMed ID14598987
'Physical changes in Flavobacterium psychrophilum, the causative agent of rainbow trout fry syndrome (RTFS), were examined over a 19 wk period of starvation. Bacteria were maintained in either Cytophaga broth, filtered stream water, or filtered distilled water, or were maintained in broth after disinfection as a negative control for dead ... More
Novel alpha-pyrones produced by a marine Pseudomonas sp. F92S91: taxonomy and biological activities.
AuthorsSingh MP, Kong F, Janso JE, Arias DA, Suarez PA, Bernan VS, Petersen PJ, Weiss WJ, Carter G, Greenstein M
JournalJ Antibiot (Tokyo)
PubMed ID15015731
'Inhibitors of the enzymes involved in fatty acid biosynthesis (FAB) have been reported as antibacterial agents. These include thiolactomycin, cerulenin, triclosan, diazoborine, naphthyridinones, aminopyridines and pyridoindoles. Our search for new FAB inhibitors, using a lacZ reporter cell-based screen, led to several confirmed hits. Culture F92S91, later identified as a Pseudomonas ... More
Nuclease activities and cell death processes associated with the development of surface cultures of Streptomyces antibioticus ETH 7451.
AuthorsFernández M, Sánchez J
JournalMicrobiology
PubMed ID11832504
'The presence and significance of developmentally regulated nucleases in Streptomyces antibioticus ETH 7451 has been studied in relation to the lytic processes occurring during differentiation. The cell-death processes have been followed in surface cultures by a propidium iodide viability assay. This has allowed the visualization of dead (membrane-damaged, red fluorescent) ... More
Significance of size and nucleic acid content heterogeneity as measured by flow cytometry in natural planktonic bacteria.
AuthorsGasol JM, Zweifel UL, Peters F, Fuhrman JA, Hagström A
JournalAppl Environ Microbiol
PubMed ID10508078
'Total bacterial abundances estimated with different epifluorescence microscopy methods (4'',6-diamidino-2-phenylindole [DAPI], SYBR Green, and Live/Dead) and with flow cytometry (Syto13) showed good correspondence throughout two microcosm experiments with coastal Mediterranean water. In the Syto13-stained samples we could differentiate bacteria with apparent high DNA (HDNA) content and bacteria with apparent low ... More
Telavancin, a multifunctional lipoglycopeptide, disrupts both cell wall synthesis and cell membrane integrity in methicillin-resistant Staphylococcus aureus.
AuthorsHiggins DL, Chang R, Debabov DV, Leung J, Wu T, Krause KM, Sandvik E, Hubbard JM, Kaniga K, Schmidt DE, Gao Q, Cass RT, Karr DE, Benton BM, Humphrey PP
JournalAntimicrob Agents Chemother
PubMed ID15728913
'The emergence and spread of multidrug-resistant gram-positive bacteria represent a serious clinical problem. Telavancin is a novel lipoglycopeptide antibiotic that possesses rapid in vitro bactericidal activity against a broad spectrum of clinically relevant gram-positive pathogens. Here we demonstrate that telavancin''s antibacterial activity derives from at least two mechanisms. As observed ... More
Molecular, biochemical and ecological characterisation of a bio-catalytic calcification reactor.
AuthorsHammes F, Boon N, Clement G, de Villiers J, Siciliano SD, Verstraete W
JournalAppl Microbiol Biotechnol
PubMed ID12883864
'Bio-catalytic calcification (BCC) reactors utilise microbial urea hydrolysis by autochthonous bacteria for the precipitation-removal of calcium, as calcite, from industrial wastewater. Due to the limited knowledge available concerning natural ureolytic microbial calcium carbonate (CaCO(3)) precipitation, the microbial ecology of BCC reactors has remained a black box to date. This paper ... More
High-content screening for biofilm assays.
AuthorsPeng F, Hoek EM, Damoiseaux R,
JournalJ Biomol Screen
PubMed ID20639506
'The authors describe a novel high-throughput screening platform that provides rapid, reliable, quantitative assessment of biofilm formation and removal on engineered surfaces. Unlike traditional biofilm assays based on plate readers, this assay platform is based on high-content screening, which allows for multiplexing to simultaneously quantify the number of bacterial adhesions ... More
Mechanistic aspects in the generation of apparent ultrahigh efficiencies for colloidal (microbial) electrokinetic separations.
AuthorsArmstrong DW, Girod M, He L, Rodriguez MA, Wei W, Zheng J, Yeung ES
JournalAnal Chem
PubMed ID12433083
'Under specific experimental conditions, the electrokinetic separation of certain microorganisms can produce peaks of very high apparent efficiencies (approximately 10(6)-10(10) theoretical plates/m). This is unusual in that no deliberate focusing mechanism was employed. To investigate this process further, the separation was monitored in real time using a charge-coupled device (CCD) ... More
Induction of TNF in human alveolar macrophages as a potential evasion mechanism of virulent Mycobacterium tuberculosis.
AuthorsEngele M, Stössel E, Castiglione K, Schwerdtner N, Wagner M, Bölcskei P, Röllinghoff M, Stenger S
JournalJ Immunol
PubMed ID11801673
'The ability of macrophages to release cytokines is crucial to the host response to intracellular infection. In particular, macrophage-derived TNF plays an important role in the host response to infection with the intracellular pathogen Mycobacterium tuberculosis. In mice, TNF is indispensable for the formation of tuberculous granulomas, which serve to ... More
Predicting the effects of chlorine on the micro-organisms of filamentous bulking activated sludges.
AuthorsSéka MA, Hammes F, Verstraete W
JournalAppl Microbiol Biotechnol
PubMed ID12764574
'Rapid and definite assessment of the effect that a specific biocide has on a specific case of filamentous bulking sludge is a much-needed tool in activated sludge wastewater treatment. The Live/Dead stain (LIVE/DEAD BacLight) distinguishing "living" and "non-living" cells, a nitrifying activity (NA) test and the oxygen uptake rate (OUR) ... More
Synthesis and characterization of non-leaching biocidal polyurethanes.
AuthorsGrapski JA, Cooper SL
JournalBiomaterials
PubMed ID11456063
'The biocidal activities of a series of quaternized polyurethanes were examined against Staphylococcus aureus and Escherichia coli. The percentage of dead cells on a surface was found to depend on the alkyl halide used for quaternization, the concentration of quaternized moieties in the polyurethane, the gram-type of the microorganism, and ... More
Surfaces of fluorinated pyridinium block copolymers with enhanced antibacterial activity.
AuthorsKrishnan S, Ward RJ, Hexemer A, Sohn KE, Lee KL, Angert ER, Fischer DA, Kramer EJ, Ober CK
JournalLangmuir
PubMed ID17154613
'Polystyrene-b-poly(4-vinylpyridine) copolymers were quaternized with 1-bromohexane and 6-perfluorooctyl-1-bromohexane. Surfaces prepared from these polymers were characterized by contact angle measurements, near-edge X-ray absorption fine structure spectroscopy and X-ray photoelectron spectroscopy. The fluorinated pyridinium surfaces showed enhanced antibacterial activity compared to their nonfluorinated counterparts. Even a polymer with a relatively low molecular ... More
Localizing and identifying living bacteria in an abiotic environment by a combination of Raman and fluorescence microscopy.
AuthorsKrause M, Rösch P, Radt B, Popp J,
JournalAnal Chem
PubMed ID18847286
'A fast, easy, and reliable identification of microorganisms is indispensable in many fields such as medicine, food production, or the pharmaceutical industry. However, in native samples, biotic particles often appear together with abiotic particles. Therefore, it is a prerequisite that biotic particles can be differentiated from abiotic particles appearing in ... More
A role for triggering receptor expressed on myeloid cells-1 in host defense during the early-induced and adaptive phases of the immune response.
'Triggering receptor expressed on myeloid cells (TREM)-1 is a cell surface molecule expressed on neutrophils and monocytes implicated in the propagation of the inflammatory response. To further characterize the function of this molecule in different phases of the immune response, we examined TREM-1 in the context of host defense against ... More
Rapid, absolute, and simultaneous quantification of specific pathogenic strain and total bacterial cells using an ultrasensitive dual-color flow cytometer.
AuthorsYang L, Wu L, Zhu S, Long Y, Hang W, Yan X,
JournalAnal Chem
PubMed ID20039721
'This paper describes a rapid and sensitive strategy for the absolute and simultaneous quantification of specific pathogenic strain and total bacterial cells in a mixture. A laboratory-built compact, high-sensitivity, dual channel flow cytometer (HSDCFCM) was modified to enable dual fluorescence detection. A bacterial cell mixture comprising heat-killed pathogenic Escherichia coli ... More
In vitro and in vivo antimicrobial activity of covalently coupled quaternary ammonium silane coatings on silicone rubber.
AuthorsGottenbos B, van der Mei HC, Klatter F, Nieuwenhuis P, Busscher HJ
JournalBiomaterials
PubMed ID11829437
'Biomaterial-centered infection is a dreaded complication associated with the use of biomedical implants. In this paper, the antimicrobial activity of silicone rubber with a covalently coupled 3-(trimethoxysilyl)-propyldimethyloctadecylammonium chloride (QAS) coating was studied in vitro and in vivo. Gram-positive Staphylococcus aureus ATCC 12600, Staphylococcus epidermidis HBH, 102, and Gram-negative Esherichia coli ... More
LIVE/DEAD BacLight : application of a new rapid staining method for direct enumeration of viable and total bacteria in drinking water.
AuthorsBoulos L, Prévost M, Barbeau B, Coallier J, Desjardins R
JournalJ Microbiol Methods
PubMed ID10395466
'A rapid epifluorescence staining method using the LIVE/DEAD Bacterial Viability Kit (BacLight) was applied to estimate both viable and total counts of bacteria in drinking water. BacLight is composed of two nucleic acid-binding stains: SYTO 9 and propidium iodide. SYTO 9 penetrates all bacterial membranes and stains the cells green, ... More
Influence of storage on monodispersed cells of Mycobacterium terrae used for quantitative carrier test prEN 14563.
AuthorsWoelk E, Goroncy-Bermes P, Sand W
JournalAppl Environ Microbiol
PubMed ID14602657
'The degree of cell clumping increased with time of storage (1% cell clumps immediately after homogenization and 3 and 6.5% after 48 and 96 h of storage, respectively), and the number of living single cells decreased. Quantitative carrier tests were carried out with these cells using ortho-phthaldialdehyde (OPA) and coco ... More
Persistence and cell culturability of biocontrol strain Pseudomonas fluorescens CHA0 under plough pan conditions in soil and influence of the anaerobic regulator gene anr.
AuthorsMascher F, Schnider-Keel U, Haas D, Défago G, Moënne-Loccoz Y
JournalEnviron Microbiol
PubMed ID12558593
'Certain fluorescent pseudomonads can protect plants from soil-borne pathogens, and it is important to understand how these biocontrol agents survive in soil. The persistence of the biocontrol strain Pseudomonas fluorescens CHA0-Rif under plough pan conditions was assessed in non-sterile soil microcosms by counting total cells (immunofluorescence microscopy), intact cells (BacLight ... More
Growth characteristics of Bartonella henselae in a novel liquid medium: primary isolation, growth-phase-dependent phage induction, and metabolic studies.
AuthorsChenoweth MR, Somerville GA, Krause DC, O'Reilly KL, Gherardini FC
JournalAppl Environ Microbiol
PubMed ID14766538
'Bartonella henselae is a zoonotic pathogen that usually causes a self-limiting infection in immunocompetent individuals but often causes potentially life-threatening infections, such as bacillary angiomatosis, in immunocompromised patients. Both diagnosis of infection and research into the molecular mechanisms of pathogenesis have been hindered by the absence of a suitable liquid ... More
Survival of Helicobacter pylori in a natural freshwater environment.
AuthorsAdams BL, Bates TC, Oliver JD
JournalAppl Environ Microbiol
PubMed ID14660399
'The mode by which Helicobacter pylori, the causative agent of most gastric ulcers, is transmitted remains undetermined. Epidemiological evidence suggests these organisms are waterborne; however, H. pylori has rarely been grown from potential water sources. This may be due to the ability of this organism to rapidly enter the viable ... More
par genes and the pathology of chromosome loss in Vibrio cholerae.
AuthorsYamaichi Y, Fogel MA, Waldor MK
JournalProc Natl Acad Sci U S A
PubMed ID17197419
'The causes and consequences of chromosome loss in bacteria with multiple chromosomes are unknown. Vibrio cholerae, the causative agent of the severe diarrheal disease cholera, has two circular chromosomes. Like many other bacterial chromosomes, both V. cholerae chromosomes contain homologues of plasmid partitioning (par) genes. In plasmids, par genes act ... More
Cell lysis and protein extraction in a microfluidic device with detection by a fluorogenic enzyme assay.
AuthorsSchilling EA, Kamholz AE, Yager P
JournalAnal Chem
PubMed ID11985310
'A critical requirement for achieving a micro total analytical system for the analysis of cells and their constituent proteins is to integrate the lysis and fractionation steps on-chip. Here, an experimental microfluidic system integrating the lysis of bacterial cells and the extraction of a large intracellular enzyme, beta-galactosidase, is demonstrated. ... More
Survival of Wolbachia pipientis in cell-free medium.
AuthorsRasgon JL, Gamston CE, Ren X,
JournalAppl Environ Microbiol
PubMed ID16950898
'Wolbachia pipientis is an obligate intracellular bacterium found in a wide range of invertebrate taxa. While over ecological timescales Wolbachia infections are maintained by strict maternal inheritance, horizontal transfer events are common over evolutionary time. To be horizontally transferred between organisms, Wolbachia bacteria must pass through and survive an extracellular ... More
Modeling shifts in microbial populations associated with health or disease.
AuthorsDalwai F, Spratt DA, Pratten J,
JournalAppl Environ Microbiol
PubMed ID16672517
'Stable microbial communities associated with health can be disrupted by altered environmental conditions. Periodontal diseases are associated with changes in the resident oral microflora. For example, as gingivitis develops, a key change in the microbial composition of dental plaque is the ascendancy of Actinomyces spp. and gram-negative rods at the ... More
Comparison of the antimicrobial effects of chlorine, silver ion, and tobramycin on biofilm.
AuthorsKim J, Pitts B, Stewart PS, Camper A, Yoon J,
JournalAntimicrob Agents Chemother
PubMed ID18195062
'The systematic understanding of how various antimicrobial agents are involved in controlling biofilms is essential in order to establish an effective strategy for biofilm control, since many antimicrobial agents are effective against planktonic cells but are ineffective when they are used against the same bacteria growing in a biofilm state. ... More
Differential trafficking of live and dead Mycobacterium marinum organisms in macrophages.
AuthorsBarker LP, George KM, Falkow S, Small PL
JournalInfect Immun
PubMed ID9119492
'We characterized the Mycobacterium marinum phagosome by using a variety of endocytic markers to follow the path of the bacteria through a mouse macrophage cell line. Using a laser confocal microscope, we found that the majority of viable M. marinum cells were in nonacidic vacuoles that did not colocalize with ... More
Phylogenetic and physiological diversity of microorganisms isolated from a deep greenland glacier ice core.
AuthorsMiteva VI, Sheridan PP, Brenchley JE
JournalAppl Environ Microbiol
PubMed ID14711643
'We studied a sample from the GISP 2 (Greenland Ice Sheet Project) ice core to determine the diversity and survival of microorganisms trapped in the ice at least 120,000 years ago. Previously, we examined the phylogenetic relationships among 16S ribosomal DNA (rDNA) sequences in a clone library obtained by PCR ... More
Laser-induced fluorescence-capillary electrophoresis and fluorescence microplate reader measurement: two methods to quantify the effect of antibiotics.
AuthorsHoerr V, Ziebuhr W, Kozitskaya S, Katzowitsch E, Holzgrabe U,
JournalAnal Chem
PubMed ID17784732
'Putative antibiotic drugs have to be classified according to their bactericidal potential. Two new methods by means of fluorescence spectroscopy (FS) using a fluorescence microplate reader (FMR) and laser-induced fluorescence capillary electrophoresis (LIF-CE), respectively, were developed for the assessment of the bactericidal efficiency using the LIVE/DEAD BacLight viability kit composed ... More
Okadaic acid-induced apoptosis in neuronal cells: evidence for an abortive mitotic attempt.
AuthorsNuydens R, de Jong M, Van Den Kieboom G, Heers C, Dispersyn G, Cornelissen F, Nuyens R, Borgers M, Geerts H
JournalJ Neurochem
PubMed ID9489733
'There is increasing evidence that apoptosis in postmitotic neurons is associated with a frustrated attempt to reenter the mitotic cycle. Okadaic acid, a specific protein phosphatase inhibitor, is currently used in models of Alzheimer''s research to increase the degree of phosphorylation of various proteins, such as the microtubule-associated protein tau. ... More
EliCell: a gel-phase dual antibody capture and detection assay to measure cytokine release from eosinophils.
AuthorsBandeira-Melo C, Gillard G, Ghiran I, Weller PF
JournalJ Immunol Methods
PubMed ID11033023
'Eosinophils contain many preformed cytokines and chemokines, which are stored in specific granules along with cationic granule proteins. Mobilization and release of these granule contents can be selective and mediated by vesicular transport. We have developed a sensitive method to detect and quantitate eosinophil vesicular transport-mediated release of specific eosinophil ... More
Assessment and interpretation of bacterial viability by using the LIVE/DEAD BacLight Kit in combination with flow cytometry.
AuthorsBerney M, Hammes F, Bosshard F, Weilenmann HU, Egli T,
JournalAppl Environ Microbiol
PubMed ID17384309
'The commercially available LIVE/DEAD BacLight kit is enjoying increased popularity among researchers in various fields of microbiology. Its use in combination with flow cytometry brought up new questions about how to interpret LIVE/DEAD staining results. Intermediate states, normally difficult to detect with epifluorescence microscopy, are a common phenomenon when the ... More
Influence of trehalose 6,6'-dimycolate (TDM) during mycobacterial infection of bone marrow macrophages.
AuthorsIndrigo J, Hunter RL, Actor JK
JournalMicrobiology
PubMed ID12101287
'The relative role of surface lipids in the innate macrophage response to infection with mycobacteria remains unknown. Trehalose 6,6''-dimycolate (TDM), a major component of the mycobacterial cell wall, can elicit hypersensitive as well as T-cell-independent foreign body responses. The T-cell-independent contribution of TDM to the primary macrophage response to mycobacterial ... More
Phylogenetic analysis of anaerobic psychrophilic enrichment cultures obtained from a greenland glacier ice core.
AuthorsSheridan PP, Miteva VI, Brenchley JE
JournalAppl Environ Microbiol
PubMed ID12676695
'The examination of microorganisms in glacial ice cores allows the phylogenetic relationships of organisms frozen for thousands of years to be compared with those of current isolates. We developed a method for aseptically sampling a sediment-containing portion of a Greenland ice core that had remained at -9 degrees C for ... More
Fluorescent method for monitoring cheese starter permeabilization and lysis.
'A fluorescence method to monitor lysis of cheese starter bacteria using dual staining with the LIVE/DEAD BacLight bacterial viability kit is described. This kit combines membrane-permeant green fluorescent nucleic acid dye SYTO 9 and membrane-impermeant red fluorescent nucleic acid dye propidium iodide (PI), staining damaged membrane cells fluorescent red and ... More
Epifluorescence microscope methods for bacterial enumeration in a 4-chlorophenol degrading consortium.
AuthorsPacheco CC, Alves CC, Barreiros L, Castro PM, Teixeira PC
JournalBiotechnol Lett
PubMed ID14969414
'Epifluorescence microscope methods, namely BacLight, direct epifluorescence filter technique and Rhodamine 123, consistently underestimated plate bacterial counts in a 4-chlorophenol degrading consortium. Cells capable of passing through 0.2 microm filters, referred as ''ultramicrocells'', were found. Although cell counts were higher when traditional methods were used, BacLight and direct epifluorescence filter ... More
Clinical significance of seeding dispersal in biofilms.
AuthorsKirov SM, Webb JS, Kjelleberg S,
JournalMicrobiology
PubMed ID16272368
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Evaluation of the LIVE/DEAD BacLight kit for detection of extremophilic archaea and visualization of microorganisms in environmental hypersaline samples.
AuthorsLeuko S, Legat A, Fendrihan S, Stan-Lotter H
JournalAppl Environ Microbiol
PubMed ID15528557
Extremophilic archaea were stained with the LIVE/DEAD BacLight kit under conditions of high ionic strength and over a pH range of 2.0 to 9.3. The reliability of the kit was tested with haloarchaea following permeabilization of the cells. Microorganisms in hypersaline environmental samples were detectable with the kit, which suggests ... More
A high-throughput screen for MscL channel activity and mutational phenotyping.
AuthorsMaurer JA, Dougherty DA
JournalBiochim Biophys Acta
PubMed ID11557017
A novel fluorescence-based screen for bacterial mechanosensitive ion-channel activity has been developed. This assay is capable of clearly distinguishing the previously observed gain of function and loss of function phenotypes for the Escherichia coli mechanosensitive channel of large conductance (Ec-MscL). The method modifies Molecular Probes' Live/Dead BacLight bacterial viability assay ... More
Biofilm formation by hyperpiliated mutants of Pseudomonas aeruginosa.
AuthorsChiang P, Burrows LL
JournalJ Bacteriol
PubMed ID12644510
Under static growth conditions, hyperpiliated, nontwitching pilT and pilU mutants of Pseudomonas aeruginosa formed dense biofilms, showing that adhesion, not twitching motility, is necessary for biofilm initiation. Under flow conditions, the pilT mutant formed mushroom-like structures larger than those of the wild type but the pilU mutant was defective in ... More
Expression of Vibrio vulnificus capsular polysaccharide inhibits biofilm formation.
AuthorsJoseph LA, Wright AC
JournalJ Bacteriol
PubMed ID14729720
Vibrio vulnificus is a human pathogen that produces lethal septicemia in susceptible persons, and the primary virulence factor for this organism is capsular polysaccharide (CPS). The role of the capsule in V. vulnificus biofilms was examined under a variety of conditions, by using either defined CPS mutants or spontaneous CPS ... More
Monitoring biofilm formation and activity in drinking water distribution networks under oligotrophic conditions.
AuthorsBoe-Hansen R, Martiny AC, Arvin E, Albrechtsen HJ
JournalWater Sci Technol
PubMed ID12701912
In this study, the construction a model distribution system suitable for studies of attached and suspended microbial consisted of two loops connected in series with a total of 140 biofilm sampling points. The biofilm from the system was studied using 11 different microbial methods and the results were compared and ... More
Comparison of animal infectivity and nucleic acid staining for assessment of Cryptosporidium parvum viability in water.
AuthorsNeumann NF, Gyürek LL, Gammie L, Finch GR, Belosevic M
JournalAppl Environ Microbiol
PubMed ID10618255
Cryptosporidium parvum oocysts were stained with the fluorogenic dyes SYTO-9 and SYTO-59 and sorted by flow cytometry in order to determine whether the fluorescent staining intensity correlated with the ability of oocysts to infect neonatal CD-1 mice. Oocysts that did not fluoresce or that displayed weak fluorescent intensity when stained ... More
Optimization of a rapid and sensitive identification system for Salmonella enteritidis by capillary electrophoresis with laser-induced fluorescence.
AuthorsShintani T, Yamada K, Torimura M
JournalFEMS Microbiol Lett
PubMed ID12044682
A system coupling capillary electrophoresis (CE) with a laser-induced fluorescence (LIF) system for the identification of Salmonella enteritidis was developed. Addition of an appropriate amount of sodium alginate and NaCl to the running buffer made it possible to obtain a reproducible sharp peak. Two fluorescent staining methods using a cell-permeable ... More
Determination of cell viability in single or mixed samples using capillary electrophoresis laser-induced fluorescence microfluidic systems.
AuthorsArmstrong DW, He L
JournalAnal Chem
PubMed ID11605830
The advent of high-efficiency microbial separations will have a profound effect on both chemistry and microbiology. For the first time, it appears that it may be possible to obtain qualitative and quantitative information on microbial systems with the accuracy, precision, speed, and throughput that currently is found for chemical systems. ... More
A death round affecting a young compartmentalized mycelium precedes aerial mycelium dismantling in confluent surface cultures of Streptomyces antibioticus.
AuthorsManteca A, Fernández M, Sánchez J,
JournalMicrobiology
PubMed ID16272390
Development-associated cell-death processes were investigated in detail during the growth and differentiation of Streptomyces antibioticus ATCC 11891 on confluent surface cultures, by using fluorescent viability probes, membrane and activity fluorescence indicators, and electron microscopy analysis. A previously unsuspected complexity was revealed, namely the presence of a very young compartmentalized mycelium ... More
Physiological changes of Salmonella typhimurium cells under osmotic and starvation conditions by image analysis.
AuthorsCaro A, Got P, Baleux B
JournalFEMS Microbiol Lett
PubMed ID10518725
The effects of starvation and salinity on the physiology of Salmonella typhimurium were investigated in a microcosm study. The physiological changes were monitored by using fluorochromes dyes such as DAPI (4',6-diamidino-2-phenylindole) for evaluation of the genomic content, CTC (5-cyano-2,3-ditolyl tetrazolium chloride) for respiratory activity and syto 9 and propidium iodide ... More
Hyaluronan release from Streptococcus pyogenes: export by an ABC transporter.
AuthorsOuskova G, Spellerberg B, Prehm P
JournalGlycobiology
PubMed ID15215229
Capsular hyaluronan of Streptococcus pyogenes is synthesized at the protoplast membrane. It is widely assumed that hyaluronan is exported by the synthase itself and that no additional protein is required for transfer through plasma membranes. However, we produced an insertional mutation that reduced the mucoid phenotype, hyaluronan production, and capsule ... More
Double-staining method for differentiation of morphological changes and membrane integrity of Campylobacter coli cells.
AuthorsAlonso JL, Mascellaro S, Moreno Y, Ferrús MA, Hernández J
JournalAppl Environ Microbiol
PubMed ID12324366
We developed a double-staining procedure involving NanoOrange dye (Molecular Probes, Eugene, Oreg.) and membrane integrity stains (LIVE/DEAD BacLight kit; Molecular Probes) to show the morphological and membrane integrity changes of Campylobacter coli cells during growth. The conversion from a spiral to a coccoid morphology via intermediary forms and the membrane ... More
Establishment of a pure culture of the hitherto uncultured unicellular cyanobacterium Aphanothece sacrum, and phylogenetic position of the organism.
AuthorsFujishiro T, Ogawa T, Matsuoka M, Nagahama K, Takeshima Y, Hagiwara H
JournalAppl Environ Microbiol
PubMed ID15184129
Aphanothece sacrum, an edible freshwater unicellular cyanobacterium, was isolated by using novel synthetic media (designated AST and AST-5xNP). The media were designed on the basis of the ratio of inorganic elements contained in A. sacrum cells cultured in a natural pond. The isolated strain exhibits unicellular rod-shaped cells approximately 6 ... More
Microbial biofilm formation and contamination of dental-unit water systems in general dental practice.
Dental-unit water systems (DUWS) harbor bacterial biofilms, which may serve as a haven for pathogens. The aim of this study was to investigate the microbial load of water from DUWS in general dental practices and the biofouling of DUWS tubing. Water and tube samples were taken from 55 dental surgeries ... More
Evidence of a charge-density threshold for optimum efficiency of biocidal cationic surfaces.
AuthorsKügler R, Bouloussa O, Rondelez F,
JournalMicrobiology
PubMed ID15870444
The deposition of organic monolayers containing quaternary ammonium groups has been shown by many authors to confer biocidal properties on a large variety of solid surfaces. In a search for the controlling factors, the authors have grafted quaternized poly(vinylpyridine) chains on glass surfaces by two different methods and varied the ... More
Planktonic-cell yield of a pseudomonad biofilm.
AuthorsBester E, Wolfaardt G, Joubert L, Garny K, Saftic S,
JournalAppl Environ Microbiol
PubMed ID16332753
Biofilm cells differ phenotypically from their free-floating counterparts. Differential growth rates in biofilms are often referred to, particularly in response to limited diffusion of oxygen and nutrients. We observed growth rates of attached Pseudomonas sp. strain CT07 cells that were notably higher than the maximum specific growth rate measured in ... More
Thermococcus coalescens sp. nov., a cell-fusing hyperthermophilic archaeon from Suiyo Seamount.
AuthorsKuwabara T, Minaba M, Iwayama Y, Inouye I, Nakashima M, Marumo K, Maruyama A, Sugai A, Itoh T, Ishibashi J, Urabe T, Kamekura M,
JournalInt J Syst Evol Microbiol
PubMed ID16280518
A cell-fusing hyperthermophilic archaeon was isolated from hydrothermal fluid obtained from Suiyo Seamount of the Izu-Bonin Arc. The isolate, TS1(T), is an irregular coccus, usually 0.5-2 microm in diameter and motile with a polar tuft of flagella. Cells in the exponential phase of growth fused at room temperature in the ... More
Calcium influences cellular and extracellular product formation during biofilm-associated growth of a marine Pseudoalteromonas sp.
AuthorsPatrauchan MA, Sarkisova S, Sauer K, Franklin MJ,
JournalMicrobiology
PubMed ID16151201
Bacteria undergo a variety of physiological changes following a switch from planktonic growth to surface-associated biofilm growth. Here, it is shown that biofilm development of a marine isolate, Pseudoalteromonas sp. 1398, results in global changes in its cytosolic and extracellular proteomes. Calcium influences these proteome responses, and affects the amount ... More
Susceptibility of Streptococcus mutans biofilms to photodynamic therapy: an in vitro study.
OBJECTIVES: The purpose of this study was to evaluate the antimicrobial effect of toluidine blue O (TBO), in combination with either a helium/neon (HeNe) laser or a light-emitting diode (LED), on the viability and architecture of Streptococcus mutans biofilms. METHODS: Biofilms were grown on hydroxyapatite discs in a constant depth ... More
Enhanced inactivation of salmonella and pseudomonas biofilms on stainless steel by use of T-128, a fresh-produce washing aid, in chlorinated wash solutions.
AuthorsShen C, Luo Y, Nou X, Bauchan G, Zhou B, Wang Q, Millner P,
JournalAppl Environ Microbiol
PubMed ID22752180
The effect of the washing aid T-128 (generally recognized as safe [GRAS] formulation, composed mainly of phosphoric acid and propylene glycol) on inactivation of Salmonella and Pseudomonas populations in biofilms on stainless steel was evaluated under conditions of increasing organic matter loads in chlorinated wash solutions dominated by hypochlorous acid. ... More
Biofilm formation by mycoplasma species and its role in environmental persistence and survival.
AuthorsMcAuliffe L, Ellis RJ, Miles K, Ayling RD, Nicholas RA,
JournalMicrobiology
PubMed ID16549656
Although mycoplasmas possess a very limited genome, little is known about their virulence mechanisms and methods of persistence in the host. Examination of a wide range of mycoplasma species found considerable variation in their ability to form a biofilm. Mycoplasma putrefaciens, M. cottewii, M. yeatsii, M. agalactiae and M. bovis ... More
Noncomplementing diploidy resulting from spontaneous zygogenesis in Escherichia coli.
AuthorsGratia JP,
JournalMicrobiology
PubMed ID16151206
With the aim of understanding sexual reproduction and phenotypic expression, a novel type of mating recently discovered in Escherichia coli was investigated. Termed spontaneous zygogenesis (or Z-mating), it differs from F-mediated conjugation. Its products proved phenotypically unstable, losing part of the phenotype for which they were selected. Inactivation of a ... More
Six month tracking of microbial growth in a metalworking fluid after system cleaning and recharging.
AuthorsVeillette M, Thorne PS, Gordon T, Duchaine C,
JournalAnn Occup Hyg
PubMed ID15280164
Large volumes of metalworking fluids (MWFs) are used in manufacturing industries for cooling and lubrication of metal pieces and tools during machining. MWFs accumulate microbial growth through continuous recirculation and reuse. We studied the progression of microbial contamination for 6 months after dumping, cleaning and recharging (DCR) of a large ... More
Persistence of Enterococcus faecalis in aquatic environments via surface interactions with copepods.
Several human pathogens and fecal-pollution indicators may persist as viable organisms in natural environments, owing to their ability to activate different types of survival strategies. These strategies include adhesion on both abiotic and biotic surfaces and the entrance to the so-called viable but nonculturable (VBNC) state. In an 18-month survey ... More
Imbalanced secretion of IL-1beta and IL-1RA in Chlamydia pneumoniae-infected mononuclear cells from COPD patients.
AuthorsRupp J, Kothe H, Mueller A, Maass M, Dalhoff K,
JournalEur Respir J
PubMed ID12952260
Balanced secretion of pro- and anti-inflammatory cytokines is essential in limiting pulmonary inflammation in respiratory infections. It was hypothesised that, in acute infection with Chlamydia pneumoniae, mononuclear cells from chronic obstructive pulmonary disease (COPD) patients lack the opportunity to compensate for the inflammatory immune response by secreting adequate amounts of ... More
Vibrio cholerae strains possess multiple strategies for abiotic and biotic surface colonization.
Despite its notoriety as a human pathogen, Vibrio cholerae is an aquatic microbe suited to live in freshwater, estuarine, and marine environments where biofilm formation may provide a selective advantage. Here we report characterization of biofilms formed on abiotic and biotic surfaces by two non-O1/O139 V. cholerae strains, TP and ... More
Solid-phase capture of proteins, spores, and bacteria.
AuthorsWeimer BC, Walsh MK, Beer C, Koka R, Wang X,
JournalAppl Environ Microbiol
PubMed ID11229925
Current methods for the detection of pathogens in food and water samples generally require a preenrichment step that allows selective enrichment of the test organism. The objective of this research was to eliminate an enrichment step to allow detection of bacteria directly in food and water samples in 30 min. ... More
Bacterial adhesion to and viability on positively charged polymer surfaces.
AuthorsTerada A, Yuasa A, Kushimoto T, Tsuneda S, Katakai A, Tamada M,
JournalMicrobiology
PubMed ID17159210
Secondary and tertiary amino groups were introduced into polymer chains grafted onto a polyethylene flat-sheet membrane to evaluate the effects of surface properties on the adhesion and viability of a strain of the Gram-negative bacterium Escherichia coli and a strain of the Gram-positive bacterium Bacillus subtilis. The characterization of the ... More
Lichens survive in space: results from the 2005 LICHENS experiment.
AuthorsSancho LG, de la Torre R, Horneck G, Ascaso C, de Los Rios A, Pintado A, Wierzchos J, Schuster M,
JournalAstrobiology
PubMed ID17630840
This experiment was aimed at establishing, for the first time, the survival capability of lichens exposed to space conditions. In particular, the damaging effect of various wavelengths of extraterrestrial solar UV radiation was studied. The lichens used were the bipolar species Rhizocarpon geographicum and Xanthoria elegans, which were collected above ... More
Carnobacterium pleistocenium sp. nov., a novel psychrotolerant, facultative anaerobe isolated from permafrost of the Fox Tunnel in Alaska.
A novel, psychrotolerant, facultative anaerobe, strain FTR1T, was isolated from Pleistocene ice from the permafrost tunnel in Fox, Alaska. Gram-positive, motile, rod-shaped cells were observed with sizes 0.6-0.7 x 0.9-1.5 microm. Growth occurred within the pH range 6.5-9.5 with optimum growth at pH 7.3-7.5. The temperature range for growth of ... More
Comparison of assays for detection of agents causing membrane damage in Staphylococcus aureus.
AuthorsO'Neill AJ, Miller K, Oliva B, Chopra I,
JournalJ Antimicrob Chemother
PubMed ID15531595
OBJECTIVES: To develop a novel beta-galactosidase leakage assay for Staphylococcus aureus and to evaluate this alongside other simple methods for detection of agents that cause membrane damage in staphylococci. METHODS: Using a PCR-based approach, a derivative of S. aureus RN4220 was constructed carrying the Escherichia coli lacZ gene under the ... More
Mechanism and use of the commercially available viability stain, BacLight.
AuthorsStocks SM,
JournalCytometry A
PubMed ID15382024
BACKGROUND: BacLight (Molecular Probes, Eugene, OR, USA) is a popular fluorescence-based two-component stain for determining bacterial cell viability. The main purpose of this work was to fully elucidate the mechanism and to determine why it is sometimes reported that cells stain simultaneously live and dead. METHODS: Solutions of DNA were ... More
Viability of endolithic micro-organisms in rocks from the McMurdo Dry Valleys of Antarctica established by confocal and fluorescence microscopy.
AuthorsWierzchos J, De Los Ríos A, Sancho LG, Ascaso C,
JournalJ Microsc
PubMed ID15369484
The rocks of the McMurdo Dry Valleys desert in Antarctica harbour endolithic communities of micro-organisms such as lichens, fungi, cyanobacteria and bacteria. Establishing the physiological status and viability of these microbial colonies in their natural microhabitat has far-reaching implications for understanding the microbial ecology of the harsh environment of this ... More
The response of Cupriavidus metallidurans CH34 to spaceflight in the international space station.
AuthorsLeys N, Baatout S, Rosier C, Dams A, s'Heeren C, Wattiez R, Mergeay M,
JournalAntonie Van Leeuwenhoek
PubMed ID19572210
The survival and behavior of Cupriavidus metallidurans strain CH34 were tested in space. In three spaceflight experiments, during three separate visits to the 'International Space Station' (ISS), strain CH34 was grown for 10-12 days at ambient temperature on mineral agar medium. Space- and earth-grown cells were compared post-flight by flow ... More
Viability staining and terminal deoxyribonucleotide transferase-mediated dUTP nick end labelling of the mycelium in submerged cultures of Streptomyces antibioticus ETH7451.
AuthorsFernandez M, Sanchez J
JournalJ Microbiol Methods
PubMed ID11714519
Viability stain and terminal deoxyribonucleotide transferase-mediated dUTP nick end labelling (TUNEL) have been applied to submerged cultures of Streptomyces antibioticus ETH7451, the last technique after a suitable permeabilization treatment. Areas of dead mycelium can be clearly delineated by the viability stain within the network of hyphae which forms the mycelial ... More
Dendritic cells are host cells for mycobacteria in vivo that trigger innate and acquired immunity.
AuthorsJiao X, Lo-Man R, Guermonprez P, Fiette L, Dériaud E, Burgaud S, Gicquel B, Winter N, Leclerc C
JournalJ Immunol
PubMed ID11801668
In the present study, we investigated in vivo the infection and APC functions of dendritic cells (DC) and macrophages (Mphi) after administration of live mycobacteria to mice. Experiments were conducted with Mycobacterium bovis bacillus Calmette-Guerin (BCG) or a rBCG expressing a reporter Ag. Following infection of mice, DC and Mphi ... More
Nucleic acid stains as indicators of Cryptosporidium parvum oocyst viability.
AuthorsBelosevic M, Guy RA, Taghi-Kilani R, Neumann NF, Gyürék LL, Liyanage LR, Millard PJ, Finch GR
JournalInt J Parasitol
PubMed ID9279581
We developed nucleic acid dye staining methodology for untreated, heat-treated and chemically inactivated C. parvum oocysts. The nucleic acid staining was compared to in vitro excystation and animal infectivity using split samples of oocysts. Among the nucleic acid stains tested, SYTO-9, hexidium and SYTO-59 stained the oocysts consistently, and the ... More
Flow cytometry demonstrates bacteriocin-induced injury to Listeria monocytogenes.
AuthorsSwarts AJ, Hastings JW, Roberts RF, von Holy A
JournalCurr Microbiol
PubMed ID9541561
Flow cytometry was used to study the effect of the bacteriocin leucocin B-TA11a on Listeria (L.) monocytogenes. Mixed proportions of dead and live control populations were analyzed by flow cytometry to determine detection limits of the Dead/Live Baclight Bacterial Viability KitTM. High correlations for flow cytometric detection of defined proportions ... More
Differential oxidative damage and expression of stress defence regulons in culturable and non-culturable Escherichia coli cells.
Potentially pathogenic bacteria, such as Escherichia coli and Vibrio cholerae, become non-culturable during stasis. The analysis of such cells has been hampered by difficulties in studying bacterial population heterogeneity. Using in situ detection of protein oxidation in single E. coli cells, and using a density-gradient centrifugation technique to separate culturable ... More
Cutting edge: dendritic cells copulsed with microbial and helminth antigens undergo modified maturation, segregate the antigens to distinct intracellular compartments, and concurrently induce microbe-specific Th1 and helminth-specific Th2 responses.
AuthorsCervi L, MacDonald AS, Kane C, Dzierszinski F, Pearce EJ
JournalJ Immunol
PubMed ID14764665
To examine the ability of dendritic cells (DC) to discriminate between helminth and microbial Ag and induce appropriately polarized Th responses, mouse DC were copulsed with the helminth Ag, schistosome egg Ag (SEA), along with the bacterium Proprionebacterium acnes, Pa, and transferred into wild-type mice. Strikingly, SEA/Pa-copulsed DC induced concurrent ... More
The ability of direct fluorescence-based, two-colour assays to detect different physiological states of oral streptococci.
AuthorsDecker EM
JournalLett Appl Microbiol
PubMed ID11555201
AIMS: To investigate the ability of six fluorescent-based, two-colour viability assays to detect different physiological growth stages of two oral streptococci species. METHODS AND RESULTS: The growth of Streptococcus sanguinis and Strep. mutans from 0 to 73 h culture periods was monitored by cell labelling with six mixtures of fluorescent ... More
Validation of an in vitro biofilm model of supragingival plaque.
AuthorsGuggenheim B, Giertsen E, Schüpbach P, Shapiro S
JournalJ Dent Res
PubMed ID11269730
The study of biofilm structure and function mandates the use of model systems for which a host of environmental variables can be rigorously controlled. We describe a model of supragingival plaque containing Actinomyces naeslundii, Veillonella dispar, Fusobacterium nucleatum, Streptococcus sobrinus, and Streptococcus oralis wherein cells are cultivated anaerobically in a ... More
Method for collecting air-water interface microbes suitable for subsequent microscopy and molecular analysis in both research and teaching laboratories.
AuthorsHenk MC
JournalAppl Environ Microbiol
PubMed ID15066847
A method has been developed for collecting air-water interface (AWI) microbes and biofilms that enables analysis of the same sample with various combinations of bright-field and fluorescence light microscopy optics, scanning and transmission electron microscopy (TEM), and atomic force microscopy. The identical sample is then subjected to molecular analysis. The ... More
Two-pronged survival strategy for the major cystic fibrosis pathogen, Pseudomonas aeruginosa, lacking the capacity to degrade nitric oxide during anaerobic respiration.
Protection from NO gas, a toxic byproduct of anaerobic respiration in Pseudomonas aeruginosa, is mediated by nitric oxide (NO) reductase (NOR), the norCB gene product. Nevertheless, a norCB mutant that accumulated approximately 13.6 microM NO paradoxically survived anaerobic growth. Transcription of genes encoding nitrate and nitrite reductases, the enzymes responsible ... More
A microfluidic bioreactor based on hydrogel-entrapped E. coli: cell viability, lysis, and intracellular enzyme reactions.
AuthorsHeo J, Thomas KJ, Seong GH, Crooks RM
JournalAnal Chem
PubMed ID12530814
Viable E. coli cells were entrapped in hydrogel micropatches photopolymerized within microfluidic systems. The microfluidic channels and the micropatches have sizes on the order of 100-500 microm. Small molecules, such as dyes and surfactants, present in the solution surrounding the hydrogel, are able to diffuse into the gel and encounter ... More
Nucleic acid stains as indicators of Giardia muris viability following cyst inactivation.
AuthorsTaghi-Kilani R, Gyürék LL, Millard PJ, Finch GR, Belosevic M
JournalInt J Parasitol
PubMed ID8875309
A reliable viability assay for Giardia is required for the development of disinfection process design criteria and pathogen monitoring by water treatment utilities. Surveys of single-staining nucleic acid dyes (stain dead parasites only), and double-staining vital dye kits from Molecular Probes (stain live and dead parasites) were conducted to assess ... More
Cold and carbon dioxide used as multi-hurdle preservation do not induce appearance of viable but non-culturable Listeria monocytogenes.
AuthorsLi J, Kolling GL, Matthews KR, Chikindas ML
JournalJ Appl Microbiol
PubMed ID12492922
AIMS: To study whether the exposure to cold (4 degrees C) and carbon dioxide which results in the elongation of Listeria cells, induces a viable but nonculturable (VBNC) state. METHODS AND RESULTS: When cold and CO2 stressed L. monocytogenes were observed under a fluorescence microscope, using the LIVE/DEAD BacLight bacteria ... More