An Assessment of Optimal Growth Conditions for Escherichia Coli

2020 ◽  
Author(s):  
Pareeni Shah
Keyword(s):  
Escherichia Coli ◽  
Optimal Growth ◽  
Growth Conditions

scholarly journals Bicarbonate Ion Stimulates the Expression of Locus of Enterocyte Effacement-Encoded Genes in Enterohemorrhagic Escherichia coli O157:H7

2002 ◽  
Vol 70 (7) ◽  
pp. 3500-3509 ◽  
Author(s):  
Hiroyuki Abe ◽  
Ichiro Tatsuno ◽  
Toru Tobe ◽  
Akiko Okutani ◽  
Chihiro Sasakawa
Keyword(s):  
Escherichia Coli ◽  
Intestinal Tract ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Luria Bertani ◽  
Enterohemorrhagic Escherichia Coli ◽  
Bacterial Adherence ◽  
Escherichia Coli O157 ◽  
Factors Affecting ◽  
Enterocyte Effacement

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) strains adhere to the intestinal mucosa and produce an attaching and effacing (A/E) lesion. Most of the genes required to produce A/E lesions are thought to be encoded by the 36-kb pathogenicity island termed the locus for enterocyte effacement (LEE). Although the mechanisms underlying the bacterial adherence, including the genes involved, are still poorly understood, the preferential adherence phenotype of EHEC is thought to depend on the nature of the genes and/or the response of these genes to changes in environmental conditions. To explore the environmental factors affecting EHEC adherence, we used an O157:H7 strain and investigated the optimal growth conditions for its adherence to Caco-2 cells. We observed that EHEC grown in Dulbecco's modified Eagle's medium (DMEM) adhered more efficiently to Caco-2 cells than EHEC grown in Luria-Bertani (LB) broth. Among the components of DMEM, only NaHCO3 was found to remarkably stimulate bacterial adherence. When bacteria were grown in LB broth containing NaHCO3, the production of intimin, Tir, EspA, and EspB was greatly enhanced compared with the production in LB broth. Indeed, the transcription of ler required for LEE-encoded gene expression was promoted in response to the concentration of NaHCO3 in LB broth. Since the concentration of NaHCO3 in the lower intestinal tract has been shown to be relatively high compared with that in the upper small intestine, our results may imply that NaHCO3 is an important signaling factor for promoting colonization of EHEC in the lower intestinal tract in humans.

scholarly journals Effects of Stress, Reactive Oxygen Species, and the SOS Response onDe NovoAcquisition of Antibiotic Resistance in Escherichia coli

2015 ◽  
Vol 60 (3) ◽  
pp. 1319-1327 ◽  
Author(s):  
Nadine Händel ◽  
Marloes Hoeksema ◽  
Marina Freijo Mata ◽  
Stanley Brul ◽  
Benno H. ter Kuile
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Cellular Response ◽  
De Novo ◽  
Sos Response ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Regulation Of Transcription ◽  
Ph Homeostasis ◽  
Content Type

Strategies to prevent the development of antibiotic resistance in bacteria are needed to reduce the threat of infectious diseases to human health. Thede novoacquisition of resistance due to mutations and/or phenotypic adaptation occurs rapidly as a result of interactions of gene expression and mutations (N. Handel, J. M. Schuurmans, Y. Feng, S. Brul, and B. H. Ter Kuile, Antimicrob Agents Chemother 58:4371–4379, 2014,http://dx.doi.org/10.1128/AAC.02892-14). In this study, the contribution of several individual genes to thede novoacquisition of antibiotic resistance inEscherichia coliwas investigated using mutants with deletions of genes known to be involved in antibiotic resistance. The results indicate thatrecA, vital for the SOS response, plays a crucial role in the development of antibiotic resistance. Likewise, deletion of global transcriptional regulators, such asgadEorsoxS, involved in pH homeostasis and superoxide removal, respectively, can slow the acquisition of resistance to a degree depending on the antibiotic. Deletion of the transcriptional regulatorsoxS, involved in superoxide removal, slowed the acquisition of resistance to enrofloxacin. Acquisition of resistance occurred at a lower rate in the presence of a second stress factor, such as a lowered pH or increased salt concentration, than in the presence of optimal growth conditions. The overall outcome suggests that a central cellular mechanism is crucial for the development of resistance and that genes involved in the regulation of transcription play an essential role. The actual cellular response, however, depends on the class of antibiotic in combination with environmental conditions.

scholarly journals Spermidine Acetyltransferase Is Required To Prevent Spermidine Toxicity at Low Temperatures in Escherichia coli

2000 ◽  
Vol 182 (19) ◽  
pp. 5373-5380 ◽  
Author(s):  
Kornvika Limsuwun ◽  
Pamela G. Jones
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Low Temperature ◽  
Low Temperatures ◽  
Cold Shock ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Cellular Growth ◽  
Ribosome Inactivation ◽  
Shock Proteins

ABSTRACT Polyamines are required for optimal growth in most cells; however, polyamine accumulation leads to inhibition of cellular growth. To reduce intracellular polyamine levels, spermidine is monoacetylated in both prokaryotes and eukaryotes. In Escherichia coli, thespeG gene encodes the spermidine acetyltransferase, which transfers the acetyl group to either the N-1 or N-8 position. In addition to polyamine accumulation, stress conditions, such as cold shock, cause an increase in the level of spermidine acetylation, suggesting an adaptive role for reduced polyamine levels under stressful growth conditions. The effect of spermidine accumulation on the growth of E. coli at low temperature was examined using a speG mutant. At 37°C, growth of the speGmutant was normal in the presence of 0.5 or 1 mM spermidine. However, following a shift to 7°C, the addition of 0.5 or 1 mM spermidine resulted in inhibition of cellular growth or cell lysis, respectively. Furthermore, at 7°C, spermidine accumulation resulted in a decrease in total protein synthesis accompanied by an increase in the synthesis of the major cold shock proteins CspA, CspB, and CspG. However, the addition of 50 mM Mg2+ restored growth and protein synthesis in the presence of 0.5 mM spermidine. The results indicate that the level of spermidine acetylation increases at low temperature to prevent spermidine toxicity. The data suggest that the excess spermidine replaces the ribosome-bound Mg2+, resulting in ribosome inactivation at low temperatures.

scholarly journals Isolation of a gene required for programmed initiation of development by Aspergillus nidulans.

1992 ◽  
Vol 12 (9) ◽  
pp. 3827-3833 ◽  
Author(s):  
T H Adams ◽  
W A Hide ◽  
L N Yager ◽  
B N Lee
Keyword(s):  
Life Cycle ◽  
Aspergillus Nidulans ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Nutrient Deprivation ◽  
Deletion Mutants ◽  
Wild Type ◽  
Microbial Development ◽  
Type Strains ◽  
Posttranscriptional Level

In contrast to many other cases in microbial development, Aspergillus nidulans conidiophore production initiates primarily as a programmed part of the life cycle rather than as a response to nutrient deprivation. Mutations in the acoD locus result in "fluffy" colonies that appear to grow faster than the wild type and proliferate as undifferentiated masses of vegetative cells. We show that unlike wild-type strains, acoD deletion mutants are unable to make conidiophores under optimal growth conditions but can be induced to conidiate when growth is nutritionally limited. The requirement for acoD in conidiophore development occurs prior to activation of brlA, a primary regulator of development. The acoD transcript is present both in vegetative hyphae prior to developmental induction and in developing cultures. However, the effects of acoD mutations are detectable only after developmental induction. We propose that acoD activity is primarily controlled at the posttranscriptional level and that it is required to direct developmentally specific changes that bring about growth inhibition and activation of brlA expression to result in conidiophore development.

scholarly journals A Rhodobacter sphaeroides Protein Mechanistically Similar to Escherichia coli DksA Regulates Photosynthetic Growth

mBio ◽  
2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Christopher W. Lennon ◽  
Kimberly C. Lemmer ◽  
Jessica L. Irons ◽  
Max I. Sellman ◽  
Timothy J. Donohue ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Structure Function ◽  
Rhodobacter Sphaeroides ◽  
Fatty Acid Content ◽  
Regulatory Protein ◽  
Growth Conditions ◽  
Globular Domain ◽  
Content Type ◽  
E Coli

ABSTRACTDksA is a global regulatory protein that, together with the alarmone ppGpp, is required for the “stringent response” to nutrient starvation in the gammaproteobacteriumEscherichia coliand for more moderate shifts between growth conditions. DksA modulates the expression of hundreds of genes, directly or indirectly. Mutants lacking a DksA homolog exhibit pleiotropic phenotypes in other gammaproteobacteria as well. Here we analyzed the DksA homolog RSP2654 in the more distantly relatedRhodobacter sphaeroides, an alphaproteobacterium. RSP2654 is 42% identical and similar in length toE. coliDksA but lacks the Zn finger motif of theE. coliDksA globular domain. Deletion of the RSP2654 gene results in defects in photosynthetic growth, impaired utilization of amino acids, and an increase in fatty acid content. RSP2654 complements the growth and regulatory defects of anE. colistrain lacking thedksAgene and modulates transcriptionin vitrowithE. coliRNA polymerase (RNAP) similarly toE. coliDksA. RSP2654 reduces RNAP-promoter complex stabilityin vitrowith RNAPs fromE. coliorR. sphaeroides, alone and synergistically with ppGpp, suggesting that even though it has limited sequence identity toE. coliDksA (DksAEc), it functions in a mechanistically similar manner. We therefore designate the RSP2654 protein DksARsp. Our work suggests that DksARsphas distinct and important physiological roles in alphaproteobacteria and will be useful for understanding structure-function relationships in DksA and the mechanism of synergy between DksA and ppGpp.IMPORTANCEThe role of DksA has been analyzed primarily in the gammaproteobacteria, in which it is best understood for its role in control of the synthesis of the translation apparatus and amino acid biosynthesis. Our work suggests that DksA plays distinct and important physiological roles in alphaproteobacteria, including the control of photosynthesis inRhodobacter sphaeroides. The study of DksARsp, should be useful for understanding structure-function relationships in the protein, including those that play a role in the little-understood synergy between DksA and ppGpp.

scholarly journals Characterization of the Antibiotic Compound No. 70 Produced byStreptomycessp. IMV-70

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Lyudmila P. Trenozhnikova ◽  
Almagul K. Khasenova ◽  
Assya S. Balgimbaeva ◽  
Galina B. Fedorova ◽  
Genrikh S. Katrukha ◽  
...  
Keyword(s):  
Optimal Growth ◽  
Growth Conditions ◽  
Culture Broth ◽  
Producer Strain ◽  
New Class ◽  
New Antibiotics ◽  
Actinomycete Strain ◽  
Main Component

We describe the actinomycete strain IMV-70 isolated from the soils of Kazakhstan, which produces potent antibiotics with high levels of antibacterial activity. After the research of its morphological, chemotaxonomic, and cultural characteristics, the strain with potential to be developed further as a novel class of antibiotics with chemotherapeutics potential was identified asStreptomycessp. IMV-70. In the process of fermentation, the strainStreptomycesspp. IMV-70 produces the antibiotic no. 70, which was isolated from the culture broth by extraction with organic solvents. Antibiotic compound no. 70 was purified and separated into individual components by HPLC, TLC, and column chromatography methods. The main component of the compound is the antibiotic 70-A, which was found to be identical to the peptolide etamycin A. Two other antibiotics 70-B and 70-C have never been described and therefore are new antibiotics. The physical-chemical and biological characteristics of these preparations were described and further researched. Determination of the optimal growth conditions to cultivate actinomycete-producer strain IMV-70 and development of methods to isolate, purify, and accumulate preparations of the new antibiotic no. 70 enable us to research further the potential of this new class of antibiotics.

Toxic properties of Aeromonas proteolytica

1974 ◽  
Vol 20 (10) ◽  
pp. 1403-1409 ◽  
Author(s):  
B. G. Foster ◽  
Mary O. Hanna
Keyword(s):  
Thermal Stability ◽  
Culture Filtrate ◽  
Hemolytic Activity ◽  
Optimal Growth ◽  
Growth Conditions ◽  
The Other ◽  
Activity Peak ◽  
Endopeptidase Activity ◽  
Time Periods ◽  
Thermal Stability Of

Aeromonas proteolytica was grown for various time periods in nutrient broth, tryptic soy broth, a semisynthetic medium, and 1 and 5% peptone under different conditions involving temperature and in continuous shake and stationary flasks. The cell-free culture filtrates were tested for hemolytic, endopeptidase, and dermonecrotic activity and optimal growth conditions for their production were determined. The dermonecrotic activity and endopeptidase activity was found to be parallel in all tests, while hemolysin was independent of the other two. Studies on the thermal stability of the culture filtrate revealed that hemolysin and dermonecrotic and endopeptidase activity were destroyed at 70 °C for 30 min. Fractionation of the filtrate by Sephadex G-200 resolved three peaks at 280 nm. Peak I was inactive; peak II contained endopeptidase and dermonecrotic and hemolytic activity; peak III contained pigment and hemolysin. Evidence is presented that the endopeptidase and dermonecrotic substance found in the cell-free filtrates of A. proteolytica grown medium appear at the same time and thus may be the same entity.

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