Effect of pH, dextrose and yeast extract on cadmium toxicity on Saccharomyces cerevisiae PE-2

Mariano-da-Silva, Samuel; Oliveira, Silvio Luiz de; Leite, César Augusto Oliveira; Prado, Renata Silva do; Faria, Francys Pimenta de; Oliveira, Rangel Camillo Nunes; Mariano-da-Silva, Fabiana Maria de Siqueira

doi:10.1590/s0101-20612009000200009

Cited by 5 publications

(2 citation statements)

References 22 publications

(28 reference statements)

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“…EN 13697 (21)). Yeast extract has been shown to decrease the toxicity of heavy metals such as cadmium (22) and heavily glycosylated mucins in respiratory droplets may offer some protection against inactivation by drying in case of enveloped viruses (23) that could be considered somewhat similar to Gram-negative bacteria with their environmentally exposed outer membrane. To put the organic content in soil load into a context, the commonly used lysogeny broth (LB; (24)) often used in laboratory conditions as a growth-supporting exposure medium contains double the amount, i.e., 15 g/L of organic ingredients.…”

Section: Resultsmentioning

confidence: 99%

Antibacterial activity of solid surfaces is critically dependent on relative humidity, inoculum volume and organic soiling

Kaur¹,

Rosenberg²,

Kook

et al. 2023

Preprint

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Antimicrobial surfaces can potentially prevent pathogen transfer between people in critical applications, e.g., health care or food industry. Antimicrobial efficacy of solid surfaces is usually assessed using wet exposure following ISO 22196 standard known to largely overestimate antimicrobial activity compared to dry conditions. While several dry test formats can be found in the literature, the semi-dry exposure scenarios e.g., oral spray or water droplets exposed to ambient environment, are less studied. Here we conducted a systematic series of experiments to determine the extent to which environmental exposure conditions influence antibacterial activity against the Gram-negativeEscherichia coliand Gram-positiveStaphylococcus aureus. Five solid surfaces based on copper, silver, and quaternary ammonium compounds with known or claimed antimicrobial properties were tested in conditions mimicking microdroplet spray or larger water droplets exposed to variable relative air humidity in the presence and absence of organic soiling. All the studied environmental parameters critically affected the antibacterial activity of the tested surfaces from no effect in high organic content and low humidity conditions to higher effect in low organic content and high humidity conditions but not reaching the effect size demonstrated in ISO 22169 format. Copper proved to be the most efficient antibacterial surface across the tested conditions followed by silver and quaternary ammonium based coating. Antimicrobial testing of surfaces using spray and droplet contamination in application-relevant environmental conditions could therefore be considered as one of the worst-case exposure scenarios relevant to dry use surfaces.

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Section: Resultsmentioning

confidence: 99%

Antibacterial activity of solid surfaces is critically dependent on relative humidity, inoculum volume and organic soiling

Kaur¹,

Rosenberg²,

Kook

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…This is probably due to the increase of metabolic activity. It was found that the chromium transport into the bacterial cell depends on energy, therefore, it is glucose dependent [33]. Thus, at high dextrose strength, chromium removal was enhanced.…”

Section: Resultsmentioning

confidence: 99%

Optimization of Chromium Removal by the Indigenous Bacterium Bacillus spp. REP02 Using the Response Surface Methodology

et al. 2011

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An indigenous bacterium, Bacillus REP02, was isolated from locally sourced chromium electroplating industrial effluents. Response surface methodology was employed to optimize the five critical medium parameters responsible for higher % Cr2+ removal by the bacterium Bacillus REP02. A three-level Box-Behnken factorial design was used to optimize K2HPO4, yeast extract, MgSO4, NH4NO3, and dextrose for Cr2+ removal. A coefficient of determination (R 2) value (0.93), model F-value (3.92) and its low P-value (F < 0.0008) along with lower value of coefficient of variation (5.39) indicated the fitness of response surface quadratic model during the present study. At optimum parameters of K2HPO4 (0.6 g L−1), yeast extract (5.5 g L−1), MgSO4 (0.04 g L−1), NH4NO3 (0.20 g L−1), and dextrose (12.50 g L−1), the model predicted 98.86% Cr2+ removal, and experimentally, 99.08% Cr2+ removal was found.

show abstract

Antibacterial activity of solid surfaces is critically dependent on relative humidity, inoculum volume, and organic soiling

Kaur,

Rosenberg,

Kook

et al. 2023

FEMS Microbes

View full text Add to dashboard Cite

Antimicrobial surface materials potentially prevent pathogen transfer from contaminated surfaces. Efficacy of such surfaces is assessed by standard methods using wet exposure conditions known to overestimate antimicrobial activity compared to dry exposure. Some dry test formats have been proposed but semi-dry exposure scenarios e.g., oral spray or water droplets exposed to ambient environment, are less studied. We aimed to determine the impact of environmental test conditions on antibacterial activity against the model species Escherichia coli and Staphylococcus aureus. Surfaces based on copper, silver, and quaternary ammonium with known or claimed antimicrobial properties were tested in conditions mimicking microdroplet spray or larger water droplets exposed to variable relative air humidity in the presence or absence of organic soiling. All the environmental parameters critically affected antibacterial activity of the tested surfaces from no effect in high-organic dry conditions to higher effect in low-organic humid conditions but not reaching the effect size demonstrated in the ISO 22169 wet format. Copper was the most efficient antibacterial surface followed by silver and quaternary ammonium based coating. Antimicrobial testing of surfaces using small droplet contamination in application-relevant conditions could therefore be considered as one of the worst-case exposure scenarios relevant to dry use surfaces.

show abstract

Effect of pH, dextrose and yeast extract on cadmium toxicity on Saccharomyces cerevisiae PE-2

Cited by 5 publications

References 22 publications

Antibacterial activity of solid surfaces is critically dependent on relative humidity, inoculum volume and organic soiling

Antibacterial activity of solid surfaces is critically dependent on relative humidity, inoculum volume and organic soiling

Optimization of Chromium Removal by the Indigenous Bacterium Bacillus spp. REP02 Using the Response Surface Methodology

Antibacterial activity of solid surfaces is critically dependent on relative humidity, inoculum volume, and organic soiling

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