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At least 847 records · Page 47Linked to original sources
PubMed1975

Effect of tweens on the production of ergot alkaloids by Aspergillus fumigatus.

Tween 80, which caused increased biomass formation, also produced the highest increase in the uptake rate of all components of the medium. The fatty acid components of the respective Tweens, i.e. palmitic acid (Tween 40), stearic acid (Tween 60), and oleic acid (Tween 80), have no effect either on alkaloid production or on substrate uptake. The fatty acid composition was different in the cell membrane of the culture supplemented with Tween 60 and facilitated the transport of metabolites into the cells.

Amino Acids↗
PubMed1982

Valine production from hydrocarbon by Micrococcus varians.

A bacterium isolated from Assam (India) soil was found to accumulate L-valine in the growth medium and was identified as Micrococcus varians. The strain grew and accumulated valine in a purely synthetic medium, but supplementation with either casamino acids or yeast extract or with both, improved the yield. The entire fermentation period could be divided into a growth phase and a production (phase which could be prolonged by adjustment of pH to neutral range. Among the different hydrocarbon and nitrogen sources tested straight run gas-oil and ammonium sulphate, respectively, were found most suitable. Antibiotics inhibited growth but stimulated extracellular valine accumulation. Vitamins stimulated growth and valine yield and an inoculum level of 10% was found to be optimal. The yield of L-valine under optimal conditions was 2.95 g/L.

Anti-Bacterial Agents↗
PubMed1977

Phosphate uptake and involvement of binding protein in Tween-80 supplemented culture of Aspergillus fumigatus.

Tween-80 supplementation in submerged culture of Aspergillus fumigatus resulted in an increase of phosphate uptake. The uptake system was characterized as saturable, energy-dependent and operating against the concentration gradient. Control and Tween 80 cultures showed similar Km values for phosphate uptake (50 micrometer). Cold osmotic shock treatment of the cultures was found to cause considerable reduction in the ability to take up phosphorus with concomitant release of the binding protein into the shock fluid. Binding protein preparation from Tween-80 supplemented cells showed more activity than that from control cells.

Aspergillus fumigatus↗
PubMed2003

Passing of fluorescein derivatives into the hyphae of Phanerochaete chrysosporium.

Fluorescein derivatives added into the growth medium were decolorized during submerged cultivation of Phanerochaete chrysosporium. The highest decrease of absorbance A450 was observed in the growth phase regardless of the presence of inducers Tween 80 or poly(ethylene glycol) (PEG). Fluorescein linked to PEG was prepared and, after addition to cultures, shown to stimulate the production of lignin peroxidase. Passing of fluorescing substances into hyphae (observed by confocal microscopy) showed that they were concentrated on some structures inside hyphae.

Culture Media↗
PubMed2003

Some properties of Plesiomonas shigelloides treated with aminoglycosides.

The effect of aminoglycoside antibiotics (amikacin, gentamicin, netilmicin and tobramycin) at sublethal concentrations (sub-MICs) on some properties of Plesiomonas shigelloides strains was evaluated. All agents decreased the bacterial surface hydrophobicity. Amikacin (1/4 of the MIC) and netilmicin (1/4 and 1/8 of the MIC) changed the hydrophobic character of P. shigelloides surface to a hydrophilic one. Treatment of the strains with aminoglycosides decreased also motility, netilmicin being the most effective. No significant changes were found in lipolytic activity of antibiotic-treated strains. In the majority of cases aminoglycosides increased sensitivity of bacteria to hydrogen peroxide. The tested antibiotics did not induce production of short-chained N-acylhomoserine lactones signal molecules. Aminoglycosides at sub-MICs affected important activities of P. shigelloides potentially associated with their virulence in dependence on strain, antibiotic and concentration.

Amikacin↗
PubMed2001

Immunogenicity and safety of three commercial influenza vaccines in institutionalized elderly.

Influenza is a leading cause of morbidity and mortality in elderly people. This prospective, observed-blind, randomized, multicenter trial compares the immunogenicity and safety of three influenza vaccines in a sample of 635 elderly residents of four nursing homes in Milano (Italy). All vaccines were well tolerated: no serious adverse events were recorded, and a small number (9 subjects) of local and systemic reactions were observed. Twenty-nine oropharyngeal swabs were taken during the season from ILI (influenza-like illness) patients, none of whom was positive for influenza and other respiratory viruses. Immunogenicity was evaluated in a subgroup of 111 subjects with blood samples obtained just before vaccination and after 4 and 12 weeks. The adjuvanted vaccines, subunit vaccine with MF59 (a-SUV) and virosome subunit vaccine (v-SUV), induced a higher antibody response than whole virus vaccine (WVV). There was no significant difference between groups that received a-SUV and v-SUV, but the a-SUV group had higher values of geometric mean titres than the v-SUV group for H1N1 and B influenza strains. These findings suggest that influenza vaccination is effective, and they underscore the importance of vaccination programs for institutionalized elderly. Further studies are needed to compare other adjuvanted vaccines in order to define their different properties.

Adjuvants, Immunologic↗
PubMed2006

Investigation of several parameters influencing signal generation in flow-through membrane-based enzyme immunoassay.

Rapid-response analytical tests that can be performed at the point of sampling are based on a visual detection system. The influence of different factors on the signal generation in a membrane-based enzyme immunoassay was investigated. The research was applied to a flow-through immunoassay for the detection of ochratoxin A (OTA). This assay format is a very convenient, simple and fast qualitative screening tool. Conjugates of OTA with horseradish peroxidase (HRP) and alkaline phosphatase (AP) were used as enzyme tracers. A new conjugate OTA-AP has been synthesized in our laboratory and its performance in the assay was compared with that of OTA-HRP. Different substrate systems for HRP and AP were compared. Several reagents, including polymers and surfactants, were tested for their possible effect on signal generation with the use of OTA-HRP conjugate. Polymers such as poly(vinyl alcohol) (PVA) and poly(ethylene glycol) (PEG) 6000 exerted a favourable effect on signal amplification, whereas surfactants negatively affected assay performance. The highest signal amplification (30-70% compared to the standard assay procedure) was achieved using 0.5% PVA in tetramethylbenzidine (TMB) Colorburst substrate solution and phosphate-buffered saline (PBS) for the washing step. It allowed more reliable visual estimation of the results from OTA-HRP assay. Exclusion of the detergent (Tween 20) from the washing solution exerted a favourable effect on assay performance using both enzyme tracers. The assay using OTA-HRP was more susceptible to matrix interferences than the assay with OTA-AP. Signal development in the matrix was better for the OTA-AP assay and visual estimation of the results was easier to perform in this case. For the analysis of spiked wheat samples, OTA-AP conjugate gave a more sensitive, stable and reproducible assay with a cut-off level of 4 microg kg(-1) for OTA. The application of the new OTA-AP conjugate resulted in improved assay performance for the food samples.

Alkaline Phosphatase↗
PubMed2001

Tween-20 activates and solubilizes the mitochondrial membrane-bound, calmodulin dependent NAD+ finase of Avena sativa L.

Among different treatments assayed, a mix of a nonionic detergent (5% Tween-20) with 0.5 m NaCl was found to solubilize a large part of the calmodulin-dependent NAD+ kinase bound to the inner mitochondrial membrane. It also stimulated its activity by increasing 7 times the maximal velocity. Activity stimulation was also observed with phosphatidylcholine, phosphatidylethanolamine and with reductants (HSO3 and DTT). This solubilized NAD+ kinase and the calmodulin-dependent cytosoluble isoform displayed distinct molecular masses, as well as different kinetic parameters. We propose that solubilization of membrane-bound NAD+ kinase could occur in vivo in Avena sativa and could generate a soluble isoform.

Avena↗
PubMed2004

Evaluation of chemical pretreatment of contaminated soil for improved PAH bioremediation.

The efficiency of several chemical treatments as potential enhancers of the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil was evaluated by analyzing the mineralization of 14C-labeled phenanthrene, pyrene, and benzo(a)pyrene. The effect of nonionic surfactants with Fenton oxidation and combinations of surfactants with the Fenton oxidation was evaluated in a microtiter plate assay. The surfactants selected for the study were Tween 80, Brij 35, Tergitol NP-10, and Triton X-100. The addition of Fenton's reagent significantly enhanced the mineralization of pyrene at the two concentrations studied: 2.8 M H2O2 with 0.1 M FeSO4 and 0.7 M H2O2 with 0.025 M FeSO4. Phenanthrene mineralization was also positively induced by the Fenton treatments. However, none of the treatments had a significant effect on benzo(a)pyrene mineralization. Surfactant additions at concentrations of 20% and 80% of the aqueous critical micelle concentration did not significantly affect the mineralization rates. When surfactant addition was combined with the Fenton oxidation, reduced mineralization rates were obtained when compared with mineralization after Fenton's treatment alone. The results indicate that the addition of Fenton's reagent may enhance the mineralization of PAHs in contaminated soil, whereas the addition of surfactants has no significant beneficial effect. The efficiency of the Fenton oxidation may decrease when surfactants are added simultaneously with Fenton's reagent to contaminated soil.

Benzo(a)pyrene↗
PubMed2005

Investigation on bioremediation of oil-polluted wetland at Liaodong Bay in northeast China.

An investigation on the effect of various microbes on degradation was carried out as part of the study on bioremediation of oil-polluted wetland at LiaoDong Bay in northeast China. The method used involved direct inoculation of selected bacteria, which were capable of degrading oil, to the soil samples. The combination of various bacteria showed better results in terms of oil degradation than any single ones due to their synergetic effects. The operation conditions [pH 8.0, 25 degrees C, C/N/P (40:5.6:1)] for these bacteria to degrade the oil content in the soil samples were also studied and optimized. Addition of appropriate surfactants was helpful for bacteria growth, thus favoring the oil degradation. For instance, after adding Tween 80 (300 mg/kg) for 8 days, the number of bacteria was amplified 6.22 times and the rate of oil degradation increased by 20%. Adequate amount of H2O2 was also beneficial for microbes to decompose oil. However, overdosage may cause the death of the bacteria. The addition of 400 mg/l H2O2 each time was suitable. Seven thousand milligrams of H2O2 was added entirely in 11 days, and the rate of oil degradation increased significantly from 27% (without H2O2) up to 67%. The study clearly demonstrated that the direct soil inoculation was an effective method for environmental bioremediation.

Biodegradation, Environmental↗
PubMed2006

Determination of soluble and granular inorganic polyphosphate in Corynebacterium glutamicum.

Corynebacterium glutamicum forms inorganic polyphosphate (poly P) that may occur as soluble (cytosolic) poly P and/or as volutin granules. A suitable method for monitoring soluble and granular poly P in C. glutamicum was developed and applied to C. glutamicum cells cultivated under different growth conditions. Under phosphate-limiting conditions, C. glutamicum did not accumulate poly P, but it rebuilt its poly P storages when phosphate became available. The poly P content of C. glutamicum growing on glucose minimal medium with sufficient phosphate varied considerably during growth. While the poly P content was minimal in the midexponential growth phase, two maxima were observed in the early exponential growth phase and at entry into the stationary growth phase. Cells in the early exponential growth phase primarily contained granular poly P, while cells entering the stationary growth phase contained soluble, cytosolic poly P. These results and those obtained for C. glutamicum cells cultivated under hypo- or hyperosmotic conditions or during glutamate production revealed that the poly P content of C. glutamicum and the partitioning between cytosolic and granular forms of poly P are dynamics and depend on the growth conditions.

Anti-Bacterial Agents↗
PubMed2006

The inhibition of aggregation of recombinant human consensus interferon-alpha mutant during Pichia pastoris fermentation.

Lower induction temperature and polyoxyethylene sorbitan monolaurate (Tween-20) were successfully used to inhibit the aggregation of recombinant human consensus interferon-alpha mutant (cIFN) during Pichia pastoris fermentation. When the induction temperature was decreased from 30 to 20 degrees C, the cIFN secreted into the medium was in the form of monomers instead of aggregates. The maximum specific activity at 20 degrees C was 4.04 times as high as that at 30 degrees C. There was no obvious effect on the cell growth at 20 degrees C, but the total protein level was decreased. Similar inhibition effect on cIFN aggregation was observed when 0.2 g l(-1) Tween-20 was added during induction. Furthermore, there was a synergistic effect found between induction temperature and Tween-20 on the inhibition of cIFN aggregation. The maximum specific activity with Tween-20 at 20 degrees C was 19.9-fold higher than that without Tween-20 at 30 degrees C.

Detergents↗