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At least 451 records · Page 25Linked to original sources
PubMed2004

Efficacy of ozone on survival and permeability of oral microorganisms.

In the present study, we examined the effect of ozonated water on oral microorganisms and dental plaque. Almost no microorganisms were detected after being treated with ozonated water (4 mg/l) for 10 s. To estimate the ozonated water-treated Streptococcus mutans, bacterial cells were stained with LIVE/DEAD BacLight Bacterial Viability Kit. Fluorescence microscopic analysis revealed that S. mutans cells were killed instantaneously in ozonated water. Some breakage of ozonated water-treated S. mutans was found by electron microscopy. When the experimental dental plaque was exposed to ozonated water, the number of viable S. mutans remarkably decreased. Ozonated water strongly inhibited the accumulation of experimental dental plaque in vitro. After the dental plaque samples from human subjects were exposed to ozonated water in vitro, almost no viable bacterial cells were detected. These results suggest that ozonated water should be useful in reducing the infections caused by oral microorganisms in dental plaque.

Aggregatibacter actinomycetemcomitans↗
PubMed1998

Influence of different uropathogenic microorganisms on human sperm motility parameters in an in vitro experiment.

The influence of different uropathogenic microorganisms (E. coli, enterococcus, Pseudomonas aeruginosa, Staphylococcus saprophyticus, Candida albicans) on human sperm motility was studied in vitro with a computer-assisted sperm analyser (CASA). Native ejaculates were prepared with the swim-up technique and adjusted to 22 x 10(6) spermatozoa ml-1. The sperm suspension was artificially infected with microorganisms in concentrations varying from 2 x 10(3) to 2 x 10(7). Sperm motility was examined directly after incubation, 2, 4 and 6 h later using the Mika motion analysis, a computer-based, automatic motility analysis. Former results with E. coli (serotype 06) could be confirmed that a significant inhibitory effect on sperm motility was associated with bacterial growth. Experiments with the enterococcus strain and Staphylococcus saprophyticus indicated no significant influence on sperm motility parameters. Tests with Pseudomonas aeruginosa showed a decrease of progressive motility according to time, but not to different bacterial concentrations. A significant inhibitory effect of Candida albicans was only detected in the samples with the initial bacterial concentration of 2 x 10(7) microorganisms ml-1.

Bacteria↗
PubMed1992

Arachidonic acid production by microorganisms.

Arachidonic acid (AA) is a natural precursor of prostaglandins, thromboxanes, leukotrienes, prostacyclins, and a large group of C20 compounds which are of intrinsic medical interest. At present, the only source of AA is animal tissues. However, it is present in several microorganisms. This review describes the production of AA by microorganisms and its recovery and the potential of microorganisms as a source of AA.

Arachidonic Acids↗
PubMed2001

Phenotypic biomonitoring using multivariate flow cytometric analysis of multi-stained microorganisms.

A new method for monitoring phenotypic profiles of pure cultures and complex microbial communities was evaluated. The approach was to stain microorganisms with a battery of fluorescent dyes prior to flow cytometry analysis (FCM) and to analyse the data using multivariate methods, including principal component analysis and partial least squares. The FCM method was quantitatively evaluated using different mixtures of pure cultures as well as microbial communities. The results showed that the method could quantitatively and reproducibly resolve both populations and communities of microorganisms with 5% abundance in a diverse microbial background. The feasibility of monitoring complex microbial communities over time during the biodegradation of naphthalene using the FCM method was demonstrated. The biodegradation of naphthalene occurred to differing extents in microcosms representing three different types of aromatic-contaminated groundwater and a sample of bio-basin water. The FCM method distinguished each of these four microbial communities. The phenotypic profiles were compared with genotypic profiles generated by random-amplified polymorphic DNA analysis. The genotypic profiles of the microbial communities described only the microbial composition, and not their functional change, whereas the phenotypic profiles seemed to contain information on both the composition and the functional change of the microorganisms. Furthermore, event analysis of the FCM data showed that microbial communities with initially differing compositions could converge towards a similar composition if they had a capacity for high levels of degradation, whereas microbial communities with similar initial compositions could diverge if they differed in biodegrading ability.

Journal Article↗
PubMed1994

Microorganisms surviving for 5300 years.

Recently, the well-preserved corpse of a prehistoric man with an age of approximately 5300 years bp was discovered in the Central European Alps. Analysis of materials associated with the individual has revealed the presence of microorganisms which are believed to have survived since the time of death. So far, two fungi have been isolated and identified as species of the genera Chaetomium and Absidia, respectively. In addition, we have obtained one bacterial isolate which we have identified as a Streptomyces species. Our findings demonstrate that microorganisms can remain viable under appropriate circumstances for thousands of years. The isolates may enable us to study evolutionary trends within microorganisms.

Animals↗
PubMed1988

The effects of periodontal therapy on serum antibody (IgG) levels to plaque microorganisms.

The influence of periodontal therapy on serum antibody titers to selected periodontal disease-associated microorganisms was assessed in 23 patients having chronic inflammatory periodontal disease (CIPD). The immunoglobulin G (IgG) titers were determined by the microELISA technique in serum samples obtained prior to treatment; following a hygienic phase which included scaling, root planing, and oral hygiene instruction; following surgical treatment; and one year and two years following hygienic phase (maintenance phase). Considerable individual variability existed in the magnitude of immune response to specific bacterial preparations. Significant reductions in the mean antibody titers were seen to A. viscosus, S. sanguis, F. nucleatum, S. sputigena, B. gingivalis, B. intermedius, B. melaninogenicus, T. vincentii, and T. denticola by the end of the second year of maintenance. There was no consistent response to Capnocytophaga. When individual patient responses were examined, 6 of the 23 were found to have elevated titers to at least one of the microorganisms in the interval between pretreatment and the end of the hygienic phase; however, in all but one case, the titers at the end of the second year of maintenance were below pretreatment levels. Antibody levels to bacteria such as S. sanguis were modified during therapy. This would indicate that immune responses to microbes not generally considered to be "periodontal pathogens" may be modified by adjuvant activity associated with subgingival plaque or changes in the environment of the sulcus and that subsequent changes in titer do not necessarily reflect a role of that microorganism in the disease process.

Adult↗
PubMed1994

Systemic diseases caused by oral microorganisms.

Human endodontic and periodontal infections are associated with complex microfloras in which approximately 150, (in apical periodontitis) and 350 (in marginal periodontitis) bacterial species have been encountered. These infections are predominantly anaerobic, with gram-negative rods being the most common isolates. The anatomic closeness of this microflora to the bloodstream can facilitate bacteremia and systemic spread of bacterial by-products and immunocomplexes. A variety of clinical procedures such as tooth extraction, periodontal and endodontic treatment, may cause translocation of microorganisms from the oral cavity to the bloodstream. The microorganisms that gain entrance to the blood circulate throughout the body, but are usually eliminated by the host (reticuloendothelial system) within minutes. However, in patients with ineffective heart valves or vascular diseases, bacteremia can be a potential danger, leading most commonly to infective endocarditis and myocardial or cerebral infarction. Other forms of systemic diseases such as brain abscesses, hematological infections and implant infections have also been related to oral microorganisms.

Bacteremia↗
PubMed1991

Radiation resistance of microorganisms on unsterilized infusion sets.

Three different methods were used for detecting and isolating microorganisms with high radiation resistance from the microbial contamination on infusion sets prior to sterilization. By all three methods, microorganisms with a radiation resistance high enough to be a critical factor in a sterilization process (D-6 value greater than or equal to 30 kGy) were found with a frequency of approximately two colony forming units (cfu) per 100 product items, even though the product items in two of the series of analyses were irradiated with doses of 3-6 kGy. The frequency of occurrence of isolates with D-6 values greater than or equal to 30 kGy was 0.45 per 1000 cfu of the total aerobic count. Eight different isolates of microorganisms had D-6 values greater than or equal to 40 kGy when irradiated in dried laboratory preparation. All but one of these were classified according to morphologic criteria as Deinococcus, and all but one had nonlinear dose-response relationships in semilogarithmic presentation.

Bacteria↗
PubMed1986

Elastase-producing microorganisms in horse lungs: their possible role in the pathogenesis of chronic pulmonary disease in the horse.

Seventeen out of 21 horses had pulmonary microbial organisms which reached considerable numbers in seven cases. Elastase-producing microorganisms from the environment (Streptomyces species and to a lesser extent Bacillus species) constituted 22 per cent to 99 per cent (mean 79 per cent) of the total growth. There was a considerable number of microorganisms with in vitro-produced elastases which were not or only slightly affected by horse serum. There was no correlation between numbers of organisms and pulmonary histopathological findings thus the significance of these microorganisms in the pathogenesis of alveolar emphysema is unknown. The growth of a strain of Streptomyces collinus/diastatochromogus isolated from the lungs was suppressed by fresh horse serum but not by decomplemented horse serum. Complement activation in response to this organism could contribute to airway inflammation through the production of mediators.

Animals↗
PubMedDate not supplied

Automatic identification of biological microorganisms using three-dimensional complex morphology.

We propose automated identification of microorganisms using three-dimensional (3-D) complex morphology. This 3-D complex morphology pattern includes the complex amplitude (magnitude and phase) of computationally reconstructed holographic images at arbitrary depths. Microscope-based single-exposure on-line (SEOL) digital holography records and reconstructs holographic images of the biological microorganisms. The 3-D automatic recognition is processed by segmentation, feature extraction by Gabor-based wavelets, automatic feature vector selection by graph matching, training rules, and a decision process. Graph matching combined with Gabor feature vectors measures the similarity of complex geometrical shapes between a reference microorganism and unknown biological samples. Automatic selection of the training data is proposed to achieve a fully automatic recognition system. Preliminary experimental results are presented for 3-D image recognition of Sphacelaria alga and Tribonema aequale alga.

Algorithms↗
PubMedDate not supplied

Volumetric three-dimensional recognition of biological microorganisms using multivariate statistical method and digital holography.

We present a new statistical approach to real-time sensing and recognition of microorganisms using digital holographic microscopy. We numerically produce many section images at different depths along a longitudinal direction from the single digital hologram of three-dimensional (3D) microorganisms in the Fresnel domain. For volumetric 3D recognition, the test pixel points are randomly selected from the section image; this procedure can be repeated with different specimens of the same microorganism. The multivariate joint density functions are calculated from the pixel values of each section image at the same random pixel points. The parameters of the statistical distributions are compared using maximum likelihood estimation and statistical inference algorithms. The performance of the proposed system is illustrated with preliminary experimental results.

Artificial Intelligence↗
PubMed2002

Isolating "uncultivable" microorganisms in pure culture in a simulated natural environment.

The majority (>99%) of microorganisms from the environment resist cultivation in the laboratory. Ribosomal RNA analysis suggests that uncultivated organisms are found in nearly every prokaryotic group, and several divisions have no known cultivable representatives. We designed a diffusion chamber that allowed the growth of previously uncultivated microorganisms in a simulated natural environment. Colonies of representative marine organisms were isolated in pure culture. These isolates did not grow on artificial media alone but formed colonies in the presence of other microorganisms. This observation may help explain the nature of microbial uncultivability.

Bacteria↗
PubMed1980

Natural products from microorganisms.

Microorganisms are capable of producing natural products with widely divergent chemical structures. Greatest attention in the past has been paid to natural products that have antibiotic properties. Natural products accumulate in fermentation broths during secondary metabolism, a characteristic of the incomplete metabolic control operative in growth-inhibited microorganisms. With this general mechanism of biosynthesis, the natural products synthesized by microorganisms would be expected to have a broad range of pharmacological activities. The directed screening for non-antibiotic natural products has been of limited scope. The expectation that new compounds of interest would be found has been validated. The pharmacologically active natural products provide previously unrecognized structures as tools for fundamental research programs, as well as offering the possibility of direct use in medicine or in industrial processes.

Anti-Bacterial Agents↗
PubMed1981

Primaquine: metabolism by microorganisms and 13C nuclear magnetic resonance assignments.

Primaquine (I), a 6-methoxy-8-aminoquinoline derivatives used for the treatment of malaria, has been subjected to metabolic studies using microorganisms. A total of 77 microorganisms (fungi and Streptomyces spp.) were evaluated for their ability to metabolize primaquine. Of these, 23 were found to convert primaquine to one or more metabolites (thin-layer chromatography analysis). Preparative scale fermentation of primaquine with four different microorganisms resulted in the isolation of two metabolites, identified as 8-(4-acetamido-1-methylbutylamino)-6-methoxyquinoline (II) and 8-(3-carboxyl-1-methylpropylamino)-6-methoxyquinoline (III). The structures of the metabolites were proposed based primarily on a comparison of the 13C nuclear magnetic resonance spectra of II and the methyl ester of III (IV) with that of primaquine. The structures of both metabolites II and III were confirmed by direct comparison with authentic samples.

Aspergillus flavus↗
PubMed1983

Correlation of microenvironmental drug concentration with inhibition of growth of microorganisms on surfaces.

Methodologies have been developed to study the concept of microenvironmental drug concentration (C*) near or around microorganisms. C* may be calculated from data on drug release from a depot site by using appropriate diffusion relationships. By following C* and correlating this with the minimum inhibitory concentration (CMIC), one could attempt to predict the effectiveness of an antiplaque agent. When C* is less than CMIC, growth would be expected to occur; when C* is higher than or equal to CMIC, growth would not be expected. Chlorhexidine diacetate was chosen for this study, which used a system involving microorganisms present on the surface of drug-treated hydroxyapatite pellets. CMIC, defined as the lowest concentration to inhibit bacterial growth, was determined independently and under conditions similar to those used in the C* experiments. Surface growth of adhering microorganisms (Streptococcus mutans SL1) was followed by scanning electron microscopy. The parameters used in the calculation of C* were determined independently. Diffusion coefficients of the drugs and the diffusion layer thickness were determined under conditions similar to those employed in the release rate studies. Surface growth was generally found to be inhibited whenever C* was significantly greater than CMIC, and growth occurred whenever C* was significantly smaller than CMIC. These findings demonstrate how C* may determine the action of a topically administered antimicrobial agent and how the various physical and chemical factors play roles in influencing this quantity.

Anti-Infective Agents, Local↗
PubMed2006

Use of flow cytometry to follow the physiological states of microorganisms in cider fermentation processes.

The flow cytometry (FC) technique used with certain fluorescent dyes (ChemChrome V6 [CV6], DRAQ5, and PI) has proven useful to label and to detect different physiological states of yeast and malolactic bacterium starters conducting cider fermentation over time (by performing sequential inoculation of microorganisms). First, the technique was tested with pure cultures of both types of microorganisms grown in synthetic media under different induced stress conditions. Metabolically active cells detected by FC and by the standard plate-counting method for both types of microorganisms in fresh overnight pure cultures gave good correlations between the two techniques in samples taken at this stage. Otherwise, combining the results obtained by FC and plating during alcoholic and malolactic fermentation over time in the cider-making process, different subpopulations were detected, showing significant differences between the methods. A small number of studies have applied the FC technique to analyze fermentation processes and mixed cultures over time. The results were used to postulate equations explaining the different physiological states in cell populations taken from fresh, pure overnight cultures under nonstress conditions or cells subjected to stress conditions over time, either under a pure-culture fermentation process (in this work, corresponding to alcoholic fermentation) or under mixed-fermentation conditions (for the malolactic-fermentation phase), that could be useful to improve the control of the processes.

Alcoholic Beverages↗
PubMed1976

Enumeration of petroleum-degrading microorganisms.

A variety of factors, including concentration of oil, antibiotics, dyes, and inoculum washes, were examined to determine their effect on the total counts of microorganisms on oil-containing media. The media found to be best for enumerating petroleum-degrading microorganisms contained 0.5% (vol/vol) oil and 0.003% phenol red, with Fungizone added for isolating bacteria and streptomycin and tetracycline added for isolating yeasts and fungi. Washing the inoculum did not improve recovery of petroleum degraders. Specifically, silica gel-oil medium and a yeast medium are recommended for enumeration of petroleum-degrading bacteria and yeasts and fungi, respectively. It is suggested that counts of petroleum degraders be expressed as percentage of the total population rather than total numbers of petroleum degraders per se. Incubation temperature and presence of oil was found to influence the numbers of petroleum-degrading microorganisms at a given sampling site.

Amphotericin B↗
PubMed1977

Response of microorganisms to an accidental gasoline spillage in an arctic freshwater ecosystem.

The response of microorganisms to an accidental spillage of 55,000 gallons of leaded gasoline into an Arctic freshwater lake was studied. Shifts in microbial populations were detected after the spillage, reflecting the migration pattern of the gasoline, enrichment for hydrocarbon utilizers, and selection for leaded-gasoline-tolerant microorganisms. Ratios of gasoline-tolerant/utilizing heterotrophs to "total" heterotrophs were found to be a sensitive indicator of the degree of hydrocarbon contamination. Respiration rates were elevated in the highly contaminated area, but did not reflect differences between moderately and lightly contaminated areas. Hydrocarbon biodegradation potential experiments showed that indigenous microorganisms could extensively convert hydrocarbons to CO(2). In situ measurement of gasoline degradation showed that, if untreated, sediment samples retained significant amounts of gasoline hydrocarbons including "volatile components" at the time the lake froze for the winter. Nutrient addition and bacterial inoculation resulted in enhanced biodegradative losses, significantly reducing the amount of residual hydrocarbons. Enhanced biodegradation, however, resulted in the appearance of compounds not detected in the gasoline. Since the contaminated lake serves as a drinking water supply, treatment to enhance microbial removal of much of the remaining gasoline still may be advisable.

Alaska↗