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1.
Capillary electrophoresis approaches have been utilized for the study of bacteria under specific experimental conditions.
The main objective within our research work was to study electrophoretic behaviors of Pseudomonas aeruginosa by means of capillary electrophoresis with UV and fluorescence detection. Edwardsiella tarda and Enteropathogenic escherichia coli were also included in the study. The results showed that proper pretreatment (vortexing or sonication) for each bacterial
sample before injection was necessary to disperse the clusters of cells, which is helpful to observe the single peaks and
better peak shape of bacteria during electrophoresis. Apart from this, it was found that ionic strength of buffer affected
mobilities of Pseudomonas aeruginosa as a result of increasing of buffer concentration from 25 mM to 150 mM. Moreover, sharp and single peaks were still observed
without significant increase of noise in the concentration range. Eventually, mixtures of bacteria were well separated under
optimized separation conditions with UV and fluorescence detection. In the mean time, comparison of concentration sensitivities
for Pseudomonas aeruginosa by UV and fluorescence detection was made. Blue light emitting diode induced fluorescence detection was found to be more
sensitive (8.5-fold higher) than UV detection with home-made fluorescence detection system. Generally, proposed CE methods for the analysis of bacteria could be potentially valuable for the monitoring of bacteria contamination in real life. 相似文献
2.
Santos Alexandre S. Sampaio Ana Paula W. Vasquez Gina S. Santa Anna Lídia M. Pereira Nei Freire Denise M. G. 《Applied biochemistry and biotechnology》2002,98(1-9):1025-1035
Culture conditions involving variations in carbon and nitrogen sources and different C:N ratios were examined with the aim
of increasing productivity in the process of rhamnolipid synthesis by Pseudomonas aeruginosa. In addition to the differences in productivity, the use of different carbon sources resulted in several proportions related
to the types of rhamnolipids synthesized (monorhamnolipids and dirhamnolipids). Furthermore, the variation in nutrients, mainly
the nitrogen source, resulted in different amounts of virulence factors, as phenazines and extracellular proteins. The data
point out a new concern in the choice of substrate to be used for rhamnolipid production by P. aeruginosa: toxic byproducts. 相似文献
3.
Fernando J. S. Oliveira Leonardo Vazquez Norberto P. De Campos Francisca P. de Fran?a 《Applied biochemistry and biotechnology》1996,131(1-3):727-737
Biosurfactants production by a strain of Pseudomonas aeruginosa using palm oil as a sole carbon source was investigated. The experiments were carried out in 500-mL conical flasks containing
100 mL of mineral media supplemented with palm oil as the sole carbon source. The P. aeruginosa FR strain was able to reduce surface tension of three tested inorganic media. Rotation velocities from 100 to 150 rpm provided
free-cell fermented media with the lowest surface tension of approx 33 mN/m. Emulsification index results of even 100% were
achieved when diesel was used as oil phase. Eight surface-active compounds produced by the bacterium were identified by mass
spectrometry. 相似文献
4.
Recent decades have revealed that many bacterial species are capable of communicating with each other, and this observation
has been largely responsible for a paradigm shift in microbiology. Whereas it was previously believed that bacteria lived
as individual cells, it is now acknowledged that bacteria preferentially live in communities in the form of primitive organisms
in which the behavior of individual cells is coordinated by cell–cell communication, known as quorum sensing (QS). Bacteria
use QS for regulation of the processes involved in their interaction with each other, their environment, and, particularly,
higher organisms We have focused on Pseudomonas aeruginosa, an opportunistic pathogen producing more than 30 QS-regulated virulence factors. P. aeruginosa causes several types of nosocomial infection, and lung infection in cystic fibrosis (CF) patients. We review the role of
QS in the protective mechanisms of P. aeruginosa and show how disruption of the QS can be used as an approach to control this cunning aggressor. 相似文献
5.
Arelí Durón-Castellanos Vanesa Zazueta-Novoa Hortencia Silva-Jiménez Yolanda Alvarado-Caudillo Eduardo Peña Cabrera Roberto Zazueta-Sandoval 《Applied biochemistry and biotechnology》2005,121(1-3):279-288
Different soluble NAD+-dependent alcohol dehydrogenase (ADH) isozymes were detected in cell-free homogenates from aerobically grown mycelia of YR-1
strain of Mucor circinelloides isolated from petroleumcontaminated soil samples. Depending on the carbon source present in the growth media, multiple NAD+-dependent ADHs were detected when hexadecane or decane was used as the sole carbon source in the culture media. ADH activities
from aerobically or anaerobically grown mycelium or yeast cells, respectively, were detected when growth medium with glucose
added was the sole carbon source; the enzyme activity exhibited optimum pH for the oxidation of different alcohols (methanol,
ethanol, and hexadecanol) similar to that of the corresponding aldehyde (≈7.0). Zymogram analysis conducted with partially
purified fractions of extracts from aerobic mycelium or anaerobic yeast cells of the YR-1 strain grown in glucose as the sole
carbon source indicated the presence of a single NAD+-dependent ADH enzyme in each case, and the activity level was higher in the yeast cells. ADH enzyme from mycelium grown in
different carbon sources showed high activity using ethanol as substrate, although higher activity was displayed when the
cells were grown in hexadecane as the sole carbon source. Zymogram analysis with these extracts showed that this particular
strain of M. circinelloides has four different isozymes with ADH activity and, interestingly, one of them, ADH4, was identified also as phenanthrene-diol-dehydrogenase,
an enzyme that possibly participates in the aromatic hydrocarbon biodegradation pathway. 相似文献
6.
《Analytical letters》2012,45(3):461-472
Abstract A new method for monitoring Pseudomonas aeruginosa growth with dimethoate (DMA) as sole carbon using the series piezoelectric quartz crystal (SPQC) and high-performance liquid chromatography (HPLC) was described. Compared with the general methods, SPQC gives real-time, multidimensional information. The determination limit of HPLC was 1.08 ng. A combined novel response model for Pseudomonas aeruginosa degrading DMA was derived. By fitting DMA reducing data, the value of the reduction rate constant (k) was obtained and in line with the actual trend. The proposed kinetic model was successfully applied to Pseudomonas aeruginosa degrading DMA. 相似文献
7.
Anti-quorum sensing activity of the diterpene phytol was evaluated in vitro for the first time. This compound (at three sub-MIC concentrations – 0.5, 0.25 and 0.125 MIC, respectively) reduced the formation of Pseudomonas aeruginosa PAO1 biofilm in the range of 74.00–84.33% exhibiting higher activity than the both positive controls used, streptomycin and ampicillin. Phytol (0.5 MIC) also effectively reduced P. aeruginosa twitching and flagella motility. Indeed, the bacteria treated were incapable of producing a twitching zone and had almost round, smooth and regular colony edges. Finally, the tested compound (0.5 MIC) exhibited good P. aeruginosa pyocyanin inhibitory activity (51.94%) practically to the same extent as streptomycin (52.09%). According to the experimental data obtained, this phytol property may inspire design of medical foods targeting P. aeruginosa quorum sensing activity. 相似文献
8.
Boris Pejin Ana Ciric Ivo Karaman Mladen Horvatovic Jasmina Glamoclija Milos Nikolic 《Natural product research》2016,30(16):1847-1850
The antibiofilm and possible antiquorum sensing effects against the strain Pseudomonas aeruginosa PAO1 of five crude extracts of the freshwater bryozoan Hyalinella punctata (Hancock, 1850) were evaluated in vitro for the first time. H. punctata ethyl acetate extract (HpEtAc) exhibited the highest antibiofilm activity reducing the biofilm formation of P. aeruginosa PAO1 in the range of 80.63–88.13%. While all tested extracts reduced the twitching motility of the aforementioned bacterial strain, HpEtAc showed to be the most effective. Finally, at a concentration of 0.5 MIC, the same extract mostly inhibited the production of pyocyanin by P. aeruginosa PAO1 (71.53%). In comparison both with the positive controls used (streptomycin and ampicillin, 67.13 and 69.77%, respectively), HpEtAc was found to inhibit pyocyanin in a higher extent. An extensive chemical characterisation of this particular extract may result in isolation and identification of novel lead compounds targeting P. aeruginosa, an opportunistic human pathogen. 相似文献
9.
《Analytical letters》2012,45(1):58-67
Abstract A new method for the rapid identification and quantification of Pseudomonas aeruginosa using multichannel series piezoelectric quartz crystal (MSPQC) was proposed. The identification of P. aeruginosa was based on the development of acetamide broth, which can selective culture P. aeruginosa and performed perfectly in MSPQC. The quantitative detection of P. aeruginosa was based on the fact that the frequency detection time (FDT) detected by MSPQC in developed medium had a linear relationship with the logarithm of its initial concentration in the range of 10–108 colony ? forming units (cfu) ml–1 (R=?0.984). The detection limit was 10 cfu ml–1. 相似文献
10.
R. P. Tengerdy J. E. Johnson J. Holló J. Tóth 《Applied biochemistry and biotechnology》1981,6(1):3-13
Pseudomonas fluorescens, immobilized on soft polyvinyl chloride granules containing up to 35% softeners as carbon source, was used for simultaneous
removal of nitrate and heavy metals. In typical continuous column operation, a 100 mg/L nitrate input solution was reduced
to a 20 mg/L output at a feeding rate of 1500 mL/h, with a capacity of 14 kg/day/m3, and with an efficiency of 79%. In the same column, Pb(NO3)2 concentration was reduced from 1.0 to 0.05−0.1 mg/L and ZnSO4 concentration was reduced from 10 to 5 mg/L.Pseudomonas aeruginosa immobilized on an O2 plasma-treated melt blown polypropylene web was used for removing 95% of a 1.7 nCi PuCl4 activity from a nuclear plant waste water in a batch operation. 相似文献
11.
Azadeh Kermanshahi Pour Orval A. Mamer David G. Cooper Milan Maric Jim A. Nicell 《Journal of mass spectrometry : JMS》2009,44(5):662-671
Metabolites from the biodegradation of a potential plasticizer 1,6‐hexanediol dibenzoate in the presence of n‐hexadecane as a co‐substrate by the common soil organism Rhodococcus rhodochrous were identified using GC/MS and Fourier transform mass spectroscopy (FTMS) techniques. Trimethylsilylation of compounds from the biodegradation broth permitted detection of the following metabolites: 1‐hexadecyl benzoate, 6‐benzoyloxyhexanoic acid, 4‐benzoyloxybutanoic acid, 6‐benzoyloxyhexan‐1‐ol and benzoic acid. The presence of these metabolites was confirmed by repeating the biodegradation with 1,6‐hexanediol di[2H5]benzoate, by measurement of their exact masses in FTMS and by comparison with available authentic materials. The results show that biodegradation of 1,6‐hexanediol dibenzoate by R. rhodochrous does not lead to the accumulation of persistent metabolites as has been reported for commercial dibenzoate plasticizers. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
12.
Kronemberger Fde A Santa Anna LM Fernandes AC Menezes RR Borges CP Freire DM 《Applied biochemistry and biotechnology》2008,147(1-3):33-45
Rhamnolipids have been pointed out as promising biosurfactants. The most studied microorganisms for the aerobic production
of these molecules are the bacteria of the genus Pseudomonas. The aim of this work was to produce a rhamnolipid-type biosurfactant in a bench-scale bioreactor by one strain of Pseudomonas aeruginosa isolated from oil environments. To study the microorganism growth and production dependency on oxygen, a nondispersive oxygenation
device was developed, and a programmable logic controller (PLC) was used to set the dissolved oxygen (DO) concentration. Using
the data stored in a computer and the predetermined characteristics of the oxygenation device, it was possible to evaluate
the oxygen uptake rate (OUR) and the specific OUR (SOUR) of this microorganism. These rates, obtained for some different DO
concentrations, were then compared to the bacterial growth, to the carbon source consumption, and to the rhamnolipid and other
virulence factors production. The SOUR presented an initial value of about 60.0 mgO2/gDW h. Then, when the exponential growth phase begins, there is a rise in this rate. After that, the SOUR reduces to about 20.0 mgO2/gDW h. The carbon source consumption is linear during the whole process. 相似文献
13.
Surface modification of PVC endotracheal tubes by oxygen glow discharge to reduce bacterial adhesion
《Surface and interface analysis : SIA》2003,35(3):301-309
A d.c. oxygen glow discharge was used to modify medical‐grade poly(vinyl chloride) (PVC) to study how surface chemistry and hydrophilicity influence Pseudomonas aeruginosa adhesion. The effects of plasma exposure time on the resulting surface, including chemical composition, wettability and roughness, were assessed using x‐ray photoelectron spectroscopy, contact angle measurements and atomic force microscopy analysis. A significant alteration in the hydrophilicity of the native PVC surface was observed after oxygen glow discharge treatment. The water contact angle decreased from ~80° to 8–20°, with a weak dependence of the exposure time used. The change in surface wettability resulted from the incorporation of oxygenated functional groups, including esters, ketones and acids, as indicated by XPS analysis. The amount of oxygen incorporation was shown to be essentially independent of plasma exposure time. However, prolonged plasma exposure resulted in increased surface roughness. Bacterial adhesion efficiency was evaluated for PVC modified by 120 s of plasma exposure, because this exposure time was determined to yield the maximum decrease in contact angle. Oxygen plasma treatment of native PVC was found to yield a 70% reduction in bacterial adhesion for the four strains of Pseudomonas aeruginosa tested. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
14.
Epithelial cell lines from several tissues show a differential sensitivity to Pseudomonas aeruginosa adherence. A549 (lung), HepG2 (liver) and Caco-2 (colon) cells presented an adhesion index of about 3, 1.5 and 5 CFU/cell, respectively, whereas Mz-Ch cell lines (gallbladder cholangiocytes) presented adhesion indexes up to 35. These variations could be associated with the variable amount of sialic acid in cell surface glycoconjugates. Moreover, the presence of free sialic acid in culture media induces the secretion by P. aeruginosa of a sialidase which is able to hydrolyze glycoconjugate-linked sialic acid. As shown with A549 cells, this specific hydrolysis increases bacterial adhesion, probably by unmasking new binding sites onto the cell surface. 相似文献
15.
There are many changes, both qualitative and quantitative, in eucalypt waste during growth and fructification of Lentinula edodes. Wet chemical analysis and near-infrared (NIR) spectroscopy were used in conjunction with multivariate regression and principal
components analysis to monitor biodegradation of eucalyptus waste during growth of several L. edodes strains. Weight and component losses of eucalypt residue after biodegradation by L. edodes strains were compared for periods of 1 to 5 mo. Decrease in cellulose, hemicellulose, and lignin contents occurred, however
it was not concomitant. Measurement of lignin degradation by NIR and wet chemical analysis indicated its attack in the early
stages of biodegradation. Selective lignin degradation by L. edodes was observed up to 2 mo of biodegradation for strains DEBIQ and FEB-14. One group of degraded substrate was identified based
on the principal component analysis (PCA) of the data on their biodegradation time. Samples treated for 5 months by L. edodes strains (DEBIQ, UFV or FEB-14) differed from other, but no discrimination was observed among them. By the end of 5 mo, NIR
analyses showed decrease of about 18–47% cellulose, 35–47% polyose and 39–60% lignin. These data were used for comparison
with those obtained by wet chemical method for the degradation of the substrate by other five L. edodes strains cultivated at the same conditons. NIR calibration developed in this study was proven to be perfectly suitable as
an analytical method to predict the changes in lignocellulose composition during biodegradation. 相似文献
16.
Bonartseva GA Myshkina VL Nikolaeva DA Kevbrina MV Kallistova AY Gerasin VA Iordanskii AL Nozhevnikova AN 《Applied biochemistry and biotechnology》2003,109(1-3):285-301
Food industry wastewater served as a carbon source for the synthesis of poly-β-hydroxybutyrate (PHB) by Azotobacter chroococcum. The content of polymer in bacterial cells grown on the raw materials reached 75%. PHB films were degraded under aerobic,
microaerobic, and anaerobic conditions in the presence and absence of nitrate by microbial populations of soil, sludges from
anaerobic and nitrifying/denitrifying reactors, and sediment from a sludge deposit site. Changes in molecular mass, crystallinity,
and mechanical properties of PHB were studied. Anaerobic degradation was accompanied by acetate formation, which was the main
intermediate utilized by denitrifying bacteria or methanogenic archaea. On a decrease in temperature from 20 to 5° C in the
presence of nitrate, the rate of PHB degradation was 7.3 times lower. Under anaerobic conditions and in the absence of nitrate,
no PHB degradation was observed, even at 11°C. The enrichment cultures of denitrifying bacteria obtained from soil and anaerobic
sludge degraded PHB films for a short time (3–7 d). The dominant species in the enrichment culture from soil were Pseudomonas fluorescens and Pseudomonas stutzeri. The rate of PHB degradation by the enrichment cultures depended on the polymer molecular weight, which reduced with time
during biodegradation. 相似文献
17.
Santa Anna L. M. Sebastian G. V. Pereira N. Alves T. L. M. Menezes E. P. Freire D. M. G. 《Applied biochemistry and biotechnology》2001,91(1-9):459-467
The Pseudomonas aeruginosa PA1 strain, isolated from the water of oil production in Sergipe, Northeast Brazil, wasevaluated as a potential rhamnolipid
type of biosurfactant producer. The production of biosurfactants was investigated using different carbon sources (n-hexadecane, paraffin oil, glycerol, and babassu oil) and inoculum concentrations (0.0016–0.008 g/L) The best results were
obtained with glycerol as the substrate and an initial cell concentration of 0.004 g/L. AC:N ratio of 22.8 led to the greatest
production of rhamnolipids (1700 mg/L) and efficiency (1.18 g of rhamnolipid/g of dry wt). 相似文献
18.
Peyton B. M. Skeen R. S. Hooker B. S. Lundman R. W. Cunningham A. B. 《Applied biochemistry and biotechnology》1995,(1):785-797
The ability of published biomass detachment rate expressions to describe experimental data obtained from porous media reactors
usingPseudomonas aeruginosa grown aerobically on glucose was evaluated. A first-order rate expression on attached biomass concentration best reflected
effluent substrate concentration for combined data sets. Detachment rate coefficientk
d1 was dependent on initial substrate concentration. Simulation of porous media reactor experiments indicated that responses
using higher influent substrate concentrations possessed greater sensitivity to variations ink
d1. Simulations of field bioremediation systems suggest the use of accurate biofilm development kinetics is important in the
prediction of well bore biofouling. 相似文献
19.
Several members of the genus Streptococcus, including S. sobrinus, S. cricetus, S. sanguis and S. mutans, are known to produce proteins capable of complexing with α-1,6 glucans. Of all the oral streptococcal groups, S. sobrinus and S. cricetus are the most readily aggregated by high molecular weight glucan (glucan T-2000), but the aggregation may be inhibited by low molecular weight glucans (glucan T-10). Some of the oral streptococci are also known to express surface hydrophobins, molecules which impart hydrophobic characteristics to their cell surfaces. When glucan T-10 was added to suspensions of S. cricetus or S. sobrinus, the bacteria were less able to adhere to hexadecane, to bind to plastics or to be aggregated by ammonium sulfate. It is concluded that the glucan rendered the bacteria more hydrophilic. In contrast, streptococci such as S. sanguis and S. mutans, incapable of aggregation by high molecular weight α-1,6 glucan, retained their hydrophobic characteristics in the presence of glucan T-10. Other bacteria, such as Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa, exhibited their same abilities to bind to hexadecane, to adhere to plastics or to be aggregated by ammonium sulfate, regardless of the presence of α-1,6 glucan. When S. cricetus or S. sobrinus were grown under conditions to minimize expression of glucan-binding lectin or when glucan-binding lectin was denatured, glucan T-10 had no effect on their hydrophobic characteristics. It appears that the complexing of α-1,6 glucan by streptococci bearing glucan-binding lectin causes the bacteria to assume a more hydrophilic character. 相似文献
20.
N. Lago J. L. Legido M. I. Paz Andrade I. Arias L. M. Casás 《Journal of Thermal Analysis and Calorimetry》2011,105(2):651-655
Microcalorimetry is an experimental technique which allows us to precisely measure the energy released as a consequence of
any transformation process. All organisms produce heat as a consequence of metabolism. The rate of heat production is an adequate
measurement of metabolic activity of organisms and their constituent parts, cells and sub-cellular levels. Microorganisms
produce small amounts of heat, in the order of 1–3 pW per cell. Despite the low quantity of heat produced by bacteria, their
exponential replication in culture medium allows their detection using microcalorimetry. This study is a microcalorimetric
study of the growth and metabolism of the bacterium Pseudomonas aeruginosa, using the heat liberated as a consequence of bacterial metabolism. With this aim, we used a Calvet microcalorimeter, inside
which two Teflon screw-capped stainless steel cells were located (sample and reference). Experiments were carried out at final
concentrations of 106, 105, 103 and 10 CFU/mL, and a constant temperature of 309.65 K was maintained within the microcalorimeter. Recording the difference
in calorific potential over time we obtained P. aeruginosa’s growth curves. The shape of these curves is characteristic and has a single phase. Thus, the heat flow curves were mathematically
studied to calculate the growth constant and generation time of this bacterium. 相似文献