scholarly journals Molecular Assay Development to Monitor the Kinetics of Viable Populations of Two Biocontrol Agents, Bacillus subtilis QST 713 and Gliocladium catenulatum J1446, in the Phyllosphere of Lettuce Leaves

Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 224
Author(s):  
Gurkan Tut ◽  
Naresh Magan ◽  
Philip Brain ◽  
Xiangming Xu
Keyword(s):  
Bacillus Subtilis ◽  
Production Systems ◽  
Biocontrol Agents ◽  
Effective Control ◽  
Propidium Monoazide ◽  
Viable Cells ◽  
Halogen Light ◽  
Temporal Tracking ◽  
Kinetics Of ◽  
Accurate Quantification

Optimising the use of biocontrol agents (BCAs) requires the temporal tracking of viable populations in the crop phyllosphere to ensure that effective control can be achieved. No sensitive systems for quantifying viable populations of commercially available BCAs, such as Bacillus subtilis and Gliocladium catenulatum, in the phyllosphere of crop plants are available. The objective of this study was to develop a method to quantify viable populations of these two BCAs in the crop phyllosphere. A molecular tool based on propidium monoazide (PMA) (PMAxx™-qPCR) capable of quantifying viable populations of these two BCAs was developed. Samples were treated with PMAxx™ (12.5–100 μM), followed by 15 min incubation, exposure to a 800 W halogen light for 30 min, DNA extraction, and quantification using qPCR. This provided a platform for using the PMAxx™-qPCR technique for both BCAs to differentiate viable from dead cells. The maximum number of dead cells blocked, based on the DNA, was 3.44 log10 for B. subtilis and 5.75 log10 for G. catenulatum. Validation studies showed that this allowed accurate quantification of viable cells. This method provided effective quantification of the temporal changes in viable populations of the BCAs in commercial formulations on lettuce leaves in polytunnel and glasshouse production systems.

scholarly journals Kinetic Analysis of tRNA-Directed Transcription Antitermination of the Bacillus subtilis glyQS Gene In Vitro

2004 ◽  
Vol 186 (16) ◽  
pp. 5392-5399 ◽  
Author(s):  
Frank J. Grundy ◽  
Tina M. Henkin
Keyword(s):  
Bacillus Subtilis ◽  
Assay System ◽  
Nascent Transcript ◽  
Vitro Assay ◽  
T Box ◽  
Transcription Antitermination ◽  
Transcriptional Pausing ◽  
Transcription Complexes ◽  
Kinetics Of

ABSTRACT Binding of uncharged tRNA to the nascent transcript promotes readthrough of a leader region transcription termination signal in genes regulated by the T box transcription antitermination mechanism. Each gene in the T box family responds independently to its cognate tRNA, with specificity determined by base pairing of the tRNA to the leader at the anticodon and acceptor ends of the tRNA. tRNA binding stabilizes an antiterminator element in the transcript that sequesters sequences that participate in formation of the terminator helix. tRNAGly-dependent antitermination of the Bacillus subtilis glyQS leader was previously demonstrated in a purified in vitro assay system. This assay system was used to investigate the kinetics of transcription through the glyQS leader and the effect of tRNA and transcription elongation factors NusA and NusG on transcriptional pausing and antitermination. Several pause sites, including a major site in the loop of stem III of the leader, were identified, and the effect of modulation of pausing on antitermination efficiency was analyzed. We found that addition of tRNAGly can promote antitermination as long as the tRNA is added before the majority of the transcription complexes reach the termination site, and variations in pausing affect the requirements for timing of tRNA addition.

scholarly journals Viability of Bacillus subtilis Cells in Airborne Bioaerosols on Face Masks

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1496
Author(s):  
Eun-Hee Lee ◽  
Yunsoo Chang ◽  
Seung-Woo Lee
Keyword(s):  
Bacillus Subtilis ◽  
World Health ◽  
The Novel ◽  
Fine Dust ◽  
Health Crisis ◽  
Viable Cells ◽  
Mask Material ◽  
Novel Coronavirus ◽  
Health Organization ◽  
Sand Dust

The coronavirus disease 2019 (COVID-19) pandemic is a general health crisis and has irreversible impacts on human societies. Globally, all people are at risk of being exposed to the novel coronavirus through transmission of airborne bioaerosols. Public health actions, such as wearing a mask, are highly recommended to reduce the transmission of infectious diseases. The appropriate use of masks is necessary for effectively preventing the transmission of airborne bioaerosols. The World Health Organization (WHO) suggests washing fabric masks or throwing away disposable masks after they are used. However, people often use masks more than once without washing or disposing them. The prolonged use of a single mask might—as a result of the user habitually touching the mask—promote the spread of pathogens from airborne bioaerosols that have accumulated on the mask. Therefore, it is necessary to evaluate how long the living components of bioaerosols can be viable on the masks. Here, we evaluated the viability of airborne Bacillus subtilis (B. subtilis) in bioaerosols filtered on woven and anti-droplet (non-woven) face masks. As a simulation of being simultaneously exposed to sand dust and bioaerosols, the viability rates of bioaerosols that had accumulated on masks were also tested against fine dust and airborne droplets containing bacteria. The bioaerosols survived on the masks immediately after the masks were used to filter the bioaerosols, and the bacteria significantly proliferated after one day of storage. Thereafter, the number of viable cells in the filtered bioaerosols gradually decreased over time, and the viability of B. subtilis in bioaerosols on the masks varied, depending on the mask material used (woven or non-woven). Despite the reduction in viability, bioaerosols containing living components were still found in both woven and anti-droplet masks even after six days of storage and it took nine days not to have found them on masks. The number of viable cells in bioaerosols on masks significantly decreased upon exposure of the masks to fine dust. The results of this study should provide useful information on how to appropriately use masks to increase their duration of effectiveness against bioaerosols.

scholarly journals Effect of Lyophilization on Survivability and Growth Kinetic of Trichoderma Strains Preserved on Various Agriculture By-Products

2017 ◽  
Vol 66 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Danuta Witkowska ◽  
Katarzyna Buska-Pisarek ◽  
Wojciech Łaba ◽  
Michał Piegza ◽  
Anna Kancelista
Keyword(s):  
Survival Rate ◽  
Growth Kinetic ◽  
High Growth ◽  
High Growth Rate ◽  
Actual Number ◽  
Viable Cells ◽  
Colony Forming Units ◽  
Beet Pulp ◽  
Kinetics Of ◽  
By Products

Growth kinetics of four Trichoderma strains was tested on lignocellulosic by-products in solid state fermentation (SSF). The strains were also analyzed for their survival rate and growth after lyophilization on these carriers. All applied monocomponent and bicomponent media were substrates for the production and preservation of Trichoderma biomass. However, the maximum number of colony forming units (CFU/g dm) was acquired on bicomponent media based on dried grass and beet pulp or grass with corn cobs, when compared to monocomponent media. Although the process of lyophilization reduced the survival rate by 50%-60%, the actual number of viable cells in obtained biopreparations remained relatively high (0.58 × 108 - 1.68 × 108 CFU/g dm). The studied strains in the preserved biopreparations were characterized by a high growth rate, as evaluated in microcultures using the Bioscreen C system.

Effective control of black Sigatoka disease using a microbial fungicide based on Bacillus subtilis EA-CB0015 culture

2015 ◽  
Vol 87 ◽  
pp. 39-46 ◽  
Author(s):  
Jaime A. Gutierrez-Monsalve ◽  
Sandra Mosquera ◽  
Lina María González-Jaramillo ◽  
John J. Mira ◽  
Valeska Villegas-Escobar
Keyword(s):  
Bacillus Subtilis ◽  
Effective Control ◽  
Black Sigatoka ◽  
Black Sigatoka Disease

scholarly journals Kinetics of saccharose fermentation by Kombucha

2014 ◽  
Vol 20 (3) ◽  
pp. 345-352 ◽  
Author(s):  
Eva Loncar ◽  
Katarina Kanuric ◽  
Radomir Malbasa ◽  
Mirjana Djuric ◽  
Spasenija Milanovic
Keyword(s):  
Empirical Model ◽  
Black Tea ◽  
Reaction Rates ◽  
Yeast Cells ◽  
Inoculum Concentration ◽  
Viable Cells ◽  
Rate Of Reaction ◽  
Kinetics Of ◽  
Derivatives Of ◽  
Very High

Kinetics of saccharose fermentation by Kombucha is not yet well defined due to lack of knowledge of reaction mechanisms taking place during this process. In this research kinetics of saccharose fermentation by Kombucha was analysed using the suggested empirical model. The data were obtained on 1.5 g L-1 of black tea, with 66.47 g L-1 of saccharose and using 10% (v/v) or 15% (v/v) of Kombucha. Total number of viable cells was as follows: approximately 5x105 of yeast cells per mL of the inoculum and approximately 2x106 of bacteria cells per mL of the inoculum. The samples were analysed after 0, 3, 4, 5, 6, 7 and 10 days. Their pH values and contents of saccharose, glucose, fructose, total acids and ethanol were determined. A saccharose concentration model was defined as sigmoidal function at 22oC and 30oC, and with 10% (v/v) and 15% (v/v) of inoculum quantity. Determination coefficients of the functions were very high (R2>0.99). Reaction rates were calculated as first derivatives of Boltzmann?s functions. No simple correlation between rate of reaction and independent variables (temperature and inoculum concentration) was found. Analysis of empirical model indicated that saccharose fermentation by Kombucha occurred according to very complex kinetics.

Electrochemical Study of Mannitol Oxidation at Nickel Oxide Electrode

2003 ◽  
Vol 68 (9) ◽  
pp. 1636-1646
Author(s):  
Domenica Tonelli ◽  
Barbara Ballarin ◽  
Mario Berrettoni ◽  
Marcello Trevisani
Keyword(s):  
Nickel Oxide ◽  
Culture Medium ◽  
Electrochemical Reaction ◽  
Oxide Electrode ◽  
Experimental Conditions ◽  
Liquid Culture Medium ◽  
Viable Cells ◽  
Nickel Oxide Electrode ◽  
Kinetics Of ◽  
Overall Kinetics

The electrocatalytic oxidation of mannitol at a nickel oxide electrode was investigated. The experimental conditions for determining mannitol concentrations have been optimised taking into account the involved electrochemistry. Unlike what previously reported in the literature, our findings lead to the conclusion that both the electrochemical reaction involving the Ni(II)/Ni(III) couple and the chemical reaction between mannitol and Ni(III) are effective in determining the overall kinetics of the electrocatalytic process. The calibration line for mannitol was linear up to 20.0 mmol l-1. Mannitol determination with the nickel oxide electrode was performed in a liquid culture medium selective for Staphylococcus aureus in order to make an indirect calibration of bacterial viable cells, but the results were not satisfactory.

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