scholarly journals Malachite Green Interferes with Postantibiotic Recovery of Mycobacteria

2012 ◽  
Vol 56 (7) ◽  
pp. 3610-3614 ◽  
Author(s):  
Ekaterina Gelman ◽  
John D. McKinney ◽  
Neeraj Dhar
Keyword(s):  
Cell Wall ◽  
Malachite Green ◽  
Culture Medium ◽  
Inhibitory Effect ◽  
Solid Culture ◽  
Content Type ◽  
Cell Wall Biogenesis ◽  
Solid Media ◽  
Solid Culture Medium ◽  
High Concentrations

ABSTRACTThe genusMycobacteriumcomprises slow-growing species with generation times ranging from hours to weeks. The protracted incubation time before colonies appear on solid culture medium can result in overgrowth by faster-growing microorganisms. To prevent contamination, the solid media used in laboratories and clinics for cultivation of mycobacteria contain the arylmethane compound malachite green, which has broad-spectrum antimicrobial activity. Malachite green has no impact on the plating efficiency of mycobacteria when cells are grown under normal conditions. However, we found that malachite green interfered with colony formation when bacteria were preexposed to antibiotics targeting cell wall biogenesis (isoniazid, ethionamide, ethambutol). This inhibitory effect of malachite green was not observed when bacteria were preexposed to antibiotics targeting cellular processes other than cell wall biogenesis (rifampin, moxifloxacin, streptomycin). Sputum specimens from tuberculosis patients are routinely evaluated on solid culture medium containing high concentrations of malachite green. This practice could lead to underestimation of bacterial loads and overestimation of chemotherapeutic efficacy.

scholarly journals Genomewide Profiling of the Enterococcus faecalis Transcriptional Response to Teixobactin Reveals CroRS as an Essential Regulator of Antimicrobial Tolerance

mSphere ◽  
2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Rachel L. Darnell ◽  
Melanie K. Knottenbelt ◽  
Francesca O. Todd Rose ◽  
Ian R. Monk ◽  
Timothy P. Stinear ◽  
...  
Keyword(s):  
Cell Wall ◽  
Enterococcus Faecalis ◽  
Transcriptional Response ◽  
Multidrug Resistant ◽  
Molecular Response ◽  
Mechanisms Of Resistance ◽  
Content Type ◽  
Development Of Resistance ◽  
Cell Wall Biogenesis ◽  
High Concentrations

ABSTRACT Teixobactin is a new antimicrobial of significant interest. It is active against a number of multidrug-resistant pathogens, including Staphylococcus aureus and Enterococcus faecalis, with no reported mechanisms of teixobactin resistance. However, historically, mechanisms of resistance always exist and arise upon introduction of a new antimicrobial into a clinical setting. Therefore, for teixobactin to remain effective long term, we need to understand how mechanisms of resistance could develop. Here we demonstrate that E. faecalis shows a remarkable intrinsic tolerance to high concentrations of teixobactin. This is of critical importance, as antimicrobial tolerance has been shown to precede the development of antimicrobial resistance. To identify potential pathways responsible for this tolerance, we determined the genomewide expression profile of E. faecalis strain JH2-2 in response to teixobactin using RNA sequencing. A total of 573 genes were differentially expressed (2.0-fold log2 change in expression) in response to teixobactin, with genes involved in cell wall biogenesis and division and transport/binding being among those that were the most upregulated. Comparative analyses of E. faecalis cell wall-targeting antimicrobial transcriptomes identified CroRS, LiaRS, and YclRK to be important two-component regulators of antimicrobial-mediated stress. Further investigation of CroRS demonstrated that deletion of croRS abolished tolerance to teixobactin and to other cell wall-targeting antimicrobials. This highlights the crucial role of CroRS in controlling the molecular response to teixobactin. IMPORTANCE Teixobactin is a new antimicrobial with no known mechanisms of resistance. Understanding how resistance could develop will be crucial to the success and longevity of teixobactin as a new potent antimicrobial. Antimicrobial tolerance has been shown to facilitate the development of resistance, and we show that E. faecalis is intrinsically tolerant to teixobactin at high concentrations. We subsequently chose E. faecalis as a model to elucidate the molecular mechanism underpinning teixobactin tolerance and how this may contribute to the development of teixobactin resistance.

scholarly journals Temporary immersion biorreators: efficient technique for the propagation of the ‘Pircinque’ strawberry

2019 ◽  
Vol 41 (1) ◽  
Author(s):  
Samila Silva Camargo ◽  
Leo Rufato ◽  
Maicon Magro ◽  
André Luiz Kulkamp de Souza
Keyword(s):  
Liquid Medium ◽  
Culture Medium ◽  
Culture Media ◽  
Time Factors ◽  
Efficient Technique ◽  
Control Treatment ◽  
Solid Culture ◽  
Temporary Immersion ◽  
Solid Culture Medium

Abstract The in vitro propagation technique via temporary immersion bioreactors is a tool that, through the culture in a liquid medium, allows an increase in the efficiency of seedling production. Several researches with the strawberry crop have shown greater efficiency of the system compared to the conventional process of micropropagation in solid medium. In this sense, the objective herein was to establish a protocol of multiplication and rooting of the ‘Pircinque’ strawberry, in temporary immersion bioreactors. Two distinct and independent studies were carried out, characterized by the multiplication and rooting stages of strawberry explants, newly introduced and registered in Brazil. Two culture media (MS and KNOP) were studied and, as a control treatment, the growth of the explants in solid culture medium was evaluated with the addition of 5 g L-1 of agar. Different immersion times of the culture medium were explored: five or eight times a day, for 15 minutes. The study was composed of the culture medium and immersion time factors, as well as the control (solid) treatment. It was verified that the use of temporary immersion bioreactors system is an efficient technique for the multiplication and rooting of explants of strawberry cv. Pircinque, when compared to the conventional method of micropropagation with the use of solid culture medium, making it possible to optimize the production of seedlings in biofactories. The MS liquid medium, in contact with explants of ‘Pircinque’ strawberry five times a day, increased the growth of the aerial part and the root system.

scholarly journals Dual Roles of FmtA in Staphylococcus aureus Cell Wall Biosynthesis and Autolysis

2012 ◽  
Vol 56 (7) ◽  
pp. 3797-3805 ◽  
Author(s):  
Aneela Qamar ◽  
Dasantila Golemi-Kotra
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Wall Stress ◽  
Microscopy Study ◽  
Dual Roles ◽  
Content Type ◽  
Teichoic Acids ◽  
Low Concentrations ◽  
High Concentrations ◽  
Wall Teichoic Acids

ABSTRACTThefmtAgene is a member of theStaphylococcus aureuscore cell wall stimulon. The FmtA protein interacts with β-lactams through formation of covalent species. Here, we show that FmtA has weakd-Ala-d-Ala-carboxypeptidase activity and is capable of covalently incorporating C14-Gly into cell walls. The fluorescence microscopy study showed that the protein is localized to the cell division septum. Furthermore, we show that wall teichoic acids interact specifically with FmtA and mediate recruitment of FmtA to theS. aureuscell wall. Subjection ofS. aureusto FmtA concentrations of 0.1 μM or less induces autolysis and biofilm production. This effect requires the presence of wall teichoic acids. At FmtA concentrations greater than 0.2 μM, autolysis and biofilm formation inS. aureusare repressed and growth is enhanced. Our findings indicate dual roles of FmtA inS. aureusgrowth, whereby at low concentrations, FmtA may modulate the activity of the major autolysin (AtlA) ofS. aureusand, at high concentrations, may participate in synthesis of cell wall peptidoglycan. These two roles of FmtA may reflect dual functions of FmtA in the absence and presence of cell wall stress, respectively.

Intracellular Biosynthesis of Fluorescent CdSe Quantum Dots inBacillus subtilis:A Strategy to Construct Signaling Bacterial Probes for Visually Detecting Interaction BetweenBacillus subtilisandStaphylococcus aureus

2015 ◽  
Vol 22 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Zheng-Yu Yan ◽  
Xiao-Xia Ai ◽  
Yi-Long Su ◽  
Xin-Ying Liu ◽  
Xiao-Hui Shan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Culture Medium ◽  
Imaging Mass Spectrometry ◽  
Cdse Quantum Dots ◽  
Mass Spectrometry Detection ◽  
New Paradigm ◽  
Solid Culture ◽  
Bacterial Interaction ◽  
Solid Culture Medium ◽  
Good Uniformity

AbstractIn this work, fluorescentBacillus subtilis(B. subtilis) cells were developed as probes for imaging applications and to explore behaviorial interaction betweenB. subtilisandStaphylococcus aureus(S. aureus). A novel biological strategy of coupling intracellular biochemical reactions for controllable biosynthesis of CdSe quantum dots by livingB. subtiliscells was demonstrated, through which highly luminant and photostable fluorescentB. subtiliscells were achieved with good uniformity. With the help of the obtained fluorescentB. subtiliscells probes,S. aureuscells responded to co-culturedB. subtilisand to aggregate. The degree of aggregation was calculated and nonlinearly fitted to a polynomial model. Systematic investigations of their interactions implied thatB. subtiliscells inhibit the growth of neighboringS. aureuscells, and this inhibition was affected by both the growth stage and the amount of surroundingB. subtiliscells. Compared to traditional methods of studying bacterial interaction between two species, such as solid culture medium colony observation and imaging mass spectrometry detection, the procedures were more simple, vivid, and photostable due to the efficient fluorescence intralabeling with less influence on the cells’ surface, which might provide a new paradigm for future visualization of microbial behavior.

scholarly journals STUDIES ON CERTAIN GROWTH PARAMETERS OF DIFFERENT PROBIOTIC STRAINS

2017 ◽  
Vol 23 (4) ◽  
pp. 19-24
Author(s):  
DUMITRA RĂDUCANU ◽  
ANA-MARIA GEORGESCU
Keyword(s):  
Nutrient Medium ◽  
Growth And Development ◽  
Culture Medium ◽  
Growth Parameters ◽  
Probiotic Bacteria ◽  
Solid Culture ◽  
Solid Culture Medium ◽  
Probiotic Strains ◽  
Direct Counting ◽  
Better Than

The researchers found that probiotics contain microorganisms belonging to genus: Streptococcus, Lactobacillus, Bacillus, Aspergillus, Saccharomyces, Enterococcus, Pediococcus, enzymes (lactoperoxidase, gluconase, nonspecific enzymes) and rumen extracts. In this study, commercial probiotic bacteria known as "Linex" were used as samples. Cultural characteristics of these probiotic bacteria have been isolated and studied. It has been found that solid culture medium (nutritional gelose) favored the growth and development of bifidobacteria better than the liquid nutrient medium (nutrient broth). Thus, the number of bifidobacteria resulting from direct counting with Thoma chamber was of 7890 cells.

scholarly journals Cultivation and growth dynamics of endophytic fungi in a solid culture medium based on sugar beet pulp

2019 ◽  
Vol 100 (1) ◽  
pp. 441-446 ◽  
Author(s):  
Beatriz R Vázquez‐de‐Aldana ◽  
María José Cuesta ◽  
Iñigo Zabalgogeazcoa
Keyword(s):  
Sugar Beet ◽  
Endophytic Fungi ◽  
Culture Medium ◽  
Growth Dynamics ◽  
Sugar Beet Pulp ◽  
Solid Culture ◽  
Solid Culture Medium ◽  
Beet Pulp

scholarly journals Msb2 Signaling Mucin Controls Activation of Cek1 Mitogen-Activated Protein Kinase in Candida albicans

2009 ◽  
Vol 8 (8) ◽  
pp. 1235-1249 ◽  
Author(s):  
Elvira Román ◽  
Fabien Cottier ◽  
Joachim F. Ernst ◽  
Jesús Pla
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Protein Kinase ◽  
Osmotic Shock ◽  
Mitogen Activated Protein Kinase ◽  
Hog Pathway ◽  
High Osmolarity ◽  
Cell Wall Biogenesis ◽  
Solid Media ◽  
Mitogen Activated Protein

ABSTRACT We have characterized the role that the Msb2 protein plays in the fungal pathogen Candida albicans by the use of mutants defective in the putative upstream components of the HOG pathway. Msb2, in cooperation with Sho1, controls the activation of the Cek1 mitogen-activated protein kinase under conditions that damage the cell wall, thus defining Msb2 as a signaling element of this pathway in the fungus. msb2 mutants display altered sensitivity to Congo red, caspofungin, zymolyase, or tunicamycin, indicating that this protein is involved in cell wall biogenesis. Msb2 (as well as Sho1 and Hst7) is involved in the transmission of the signal toward Cek1 mediated by the Cdc42 GTPase, as revealed by the use of activated alleles (Cdc42G12V) of this protein. msb2 mutants have a stronger defective invasion phenotype than sho1 mutants when tested on certain solid media that use mannitol or sucrose as a carbon source or under hypoxia. Interestingly, Msb2 contributes to growth under conditions of high osmolarity when both branches of the HOG pathway are altered, as triple ssk1 msb2 sho1 mutants (but not any single or double mutant) are osmosensitive. However, this phenomenon is independent of the presence of Hog1, as Hog1 phosphorylation, Hog1 translocation to the nucleus, and glycerol accumulation are not affected in this mutant following an osmotic shock. These results reveal essential functions in morphogenesis, invasion, cell wall biogenesis, and growth under conditions of high osmolarity for Msb2 in C. albicans and suggest the divergence and specialization of this signaling pathway in filamentous fungi.

Use of temporary immersion bioreactors and solid culture medium in the in vitro propagation of pear rootstocks

2021 ◽  
pp. 113-120
Author(s):  
A.L. Arruda ◽  
F.R. Nerbass ◽  
A.A. Kretzschmar ◽  
L. Rufato ◽  
A.J. Posser ◽  
...  
Keyword(s):  
In Vitro Propagation ◽  
Culture Medium ◽  
Solid Culture ◽  
Temporary Immersion ◽  
Solid Culture Medium

scholarly journals Metabolomics Guides Rational Development of a Simplified Cell Culture Medium for Drug Screening against Trypanosoma brucei

2013 ◽  
Vol 57 (6) ◽  
pp. 2768-2779 ◽  
Author(s):  
Darren J. Creek ◽  
Brunda Nijagal ◽  
Dong-Hyun Kim ◽  
Federico Rojas ◽  
Keith R. Matthews ◽  
...  
Keyword(s):  
Cell Culture ◽  
Trypanosoma Brucei ◽  
Culture Medium ◽  
Culture Media ◽  
Culture Methods ◽  
Content Type ◽  
Drug Activity ◽  
Rational Development ◽  
High Concentrations

ABSTRACTIn vitroculture methods underpin many experimental approaches to biology and drug discovery. The modification of established cell culture methods to make them more biologically relevant or to optimize growth is traditionally a laborious task. Emerging metabolomic technology enables the rapid evaluation of intra- and extracellular metabolites and can be applied to the rational development of cell culture media. In this study, untargeted semiquantitative and targeted quantitative metabolomic analyses of fresh and spent media revealed the major nutritional requirements for the growth of bloodstream formTrypanosoma brucei. The standard culture medium (HMI11) contained unnecessarily high concentrations of 32 nutrients that were subsequently removed to make the concentrations more closely resemble those normally found in blood. Our new medium, Creek's minimal medium (CMM), supportsin vitrogrowth equivalent to that in HMI11 and causes no significant perturbation of metabolite levels for 94% of the detected metabolome (<3-fold change; α = 0.05). Importantly, improved sensitivity was observed for drug activity studies in whole-cell phenotypic screenings and in the metabolomic mode of action assays. Four-hundred-fold 50% inhibitory concentration decreases were observed for pentamidine and methotrexate, suggesting inhibition of activity by nutrients present in HMI11. CMM is suitable for routine cell culture and offers important advantages for metabolomic studies and drug activity screening.

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