Search results for "Microbio"

The effect of amphiphilic compounds on the secretion of levansucrase by Zymomonas mobilis

2005

Abstract The effect of some aliphatic (n-butanol to n-hexadecanol) and aromatic (benzyl and phenethyl alcohols), anesthetics (procaine) and surfactants (Tween 20 to Tween 80) on the secretion of levansucrase by the levan-producing strain of Gram-negative ethanologenic bacteria Zymomonas mobilis 113S were examined in this study. During incubation of Z. mobilis cells with sucrose (10 mM) a decrease of the levansucrase activity was observed in the presence of these amphiphilic compounds concomitantly with an increase of a total amount of protein in the medium. Since none of the compounds under study had any effect on enzyme activity in vitro observed structure- and concentration-dependent rela…

High aerobic growth with low respiratory rate: The ndh-deficient Zymomonas mobilis

2007

High-Temperature Short-Time Inactivation of Peroxidase by Direct Heating with a Five-Channel Computer-Controlled Thermoresistometer

1997

The thermal inactivation kinetics of horseradish and asparagus peroxidase in high-temperature short-time conditions was studied by heating in a five-channel computer-controlled thermoresistometer. Horseradish peroxidase was heated between 111.5 and 145°C and the reaction was analyzed assuming that two isoenzymes with EaL = 44.1 and Eas = 22.0 kcal/mol were present. Asparagus peroxidase heated from 110 to l20°C reacted with first-order kinetics, with Ea = 20 kcal/mol. The five-channel computer-controlled thermoresistometer enabled us to study the inactivation kinetics of the more labile fraction of horseradish peroxidase at temperatures above 100°C; this equipment was suitable for studying t…

Propanediol-1,2-dehydratase and metabolism of glycerol of Lactobacillus brevis

1984

While most strains of heterofermentative lactobacilli and strains of Leuconostoc species contained only traces of a dehydratase reacting with glycerol or propanediol-1,2, three strains of Lactobacillus brevis and one strain of L. buchneri that metabolized glycerol readily in the presence of glucose, contained propanediol-1,2 dehydratase (EC 4.2.1.28). This cobamide requiring enzyme from L. brevis B 18 was partially purified. It reacts with the substrates propanediol-1,2, glycerol and ethanediol-1,2 with the relative activities of about 3:2:1. This ratio remained unchanged throughout the purification procedure. The substrate affinities were measured: propanediol-1,2 K m=0.6 mM, glycerol K m=…

PHB-based films as matrices for pesticides

2002

Abstract The effects of pesticides incorporated into PHB-based polymeric matrices on the biodegradability of films and antifungal efficiency of immobilised pesticides to Botrytis cinerea was studied. The mass loss of tested PHB-based films for 2 weeks was 40–50% and after 4 weeks 92–96% of the initial mass. The fungicides Ronilan and Sumilex immobilised into the polymeric matrices did not depress the film degradation rate. PHB-based films caused changes in the soil microorganism association. Fungicides immobilised in PHB-based matrices decreased the count of the phytopathogenic fungus B. cinerea.

Nitric Oxide Reductase (P450nor) from Fusarium oxysporum

2008

Inhibition of bacterial virulence factors of foodborne pathogens by paprika (Capsicum annuum L.) extracts

2022

Abstract Capsicum annuum extracts of different polarities were tested for their antimicrobial, antibiofilm, and anti-Quorum sensing (QS) activity against several pathogenic microorganisms and possible toxic effects using an in vivo model (Galleria mellonella L.). Hexane (HE) and Chloroform extract (CE) were the most active in inhibiting biofilm formation of the eight bacteria tested, with inhibition percentages between 22 and 88% for a concentration of 100 μg/mL. These extracts were potent inhibitors of Staphylococcus aureus biofilm, and microscopy analysis confirmed a significant reduction in adhered cells. Moreover, polystyrene surfaces coated with these extracts decreased Staph. aureus a…

DNA strand break induction, mutagenicity, and cytotoxicity of the mycotoxins 11-β-hydroxy-7-deoxy-rosenonolactone, rosenonolactone, and trichothecin.

1992

11-β-hydroxy-7-deoxy-rosenonolactone (TSS1), a mycotoxin of the rosenane class, was tested on cytotoxicity, induction of DNA single strand breaks and muta-genicity. Its effects were compared to those of rosenonolactone and trichothecin. TSS1 had stronger antibiotic activity againstEscherichia coli (EC 50: 10μg/mL) than rosenonolactone (EC 50: >200μg/mL) but weaker activity than trichothecin (EC 50: 3μg/mL). The same order of activity was found for the inhibition of yeast fermentation (EC 50 of TSS1: 45μg/mL; EC 50 of rosenonolactone: > 120μg/mL; EC 50 of trichothecin: 3.4μg/mL). In the trypan blue exclusion test using V79 Chinese hamster cells, TSS1 proved to be cytotoxic (EC50: 30μg/mL) at…

Thermal Degradation of Green Asparagus Texture

2019

A cutting cell was developed to evaluate the texture of green asparagus by measuring its resistance to being cut with a wire. The cell was used in conjunction with a universal texturometer and improved on the single-point method of the Wilder fibrometer. Experimental conditions were determined for using the cell to measure the cutting resistance of asparagus subjected to different extents of heat treatment. Better discrimination between samples was obtained than with a Kramer cell. The fresh asparagus spears. were heated at temperatures between 70 and 100°C for different lengths of time and the kinetics of the degradation of texture was studied. A biphasic (two-component) behavior was obser…

ChemInform Abstract: One-Step Synthesis, Crystallographic Studies and Antimicrobial Activity of New 4-Diazopyrazole Derivatives.

2010

Summary A number of new 4-diazopyrazole derivatives were prepared by the reaction of 1- R -3-methyl-5(R 1 -substituted)benzamidopyrazoles with a sevenfold excess of nitrous acid in acetic medium. The compounds were tested for activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus faecalis, Listeria monocytogenes, Candida albicans, Candida tropicalis and Paecilomyces varioti . The highest microbial susceptibility was shown by Gram-positive bacteria, with minimum inhibitory concentrations (MIC) in the range 0.5–12.5 μg/mL. For S aureus the R 1 substituents were screened utilizing the Topliss operational scheme. The 4-nitro g…