scholarly journals Plasticity in Escherichia coli cell wall metabolism promotes fitness and mediates intrinsic antibiotic resistance across environmental conditions

2018 ◽  
Author(s):  
Elizabeth A Mueller ◽  
Petra Anne Levin
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Growth Parameter ◽  
Culture Conditions ◽  
Cell Wall Integrity ◽  
Bacterial Cells ◽  
Intrinsic Resistance ◽  
Wide Range ◽  
Peptidoglycan Cell Wall ◽  
Wide Ph Range

ABSTRACTAlthough the peptidoglycan cell wall is an essential structural and morphological feature of most bacterial cells, the extracytoplasmic enzymes involved in its synthesis are frequently dispensable under standard culture conditions. By modulating a single growth parameter—extracellular pH—we discovered a subset of these so-called “redundant” enzymes in Escherichia coli are required for maximal fitness across pH environments. Among these pH specialists are the class A penicillin binding proteins PBP1 a and PBP1 b; defects in these enzymes attenuate growth in alkaline and acidic conditions, respectively. Genetic, biochemical, and cytological studies demonstrate that synthase activity is required for cell wall integrity across a wide pH range, and differential activity across pH environments significantly alters intrinsic resistance to cell wall active antibiotics. Together, our findings reveal previously thought to be redundant enzymes are instead specialized for distinct environmental niches, thereby ensuring robust growth and cell wall integrity in a wide range of conditions.

scholarly journals Plasticity of Escherichia coli cell wall metabolism promotes fitness and antibiotic resistance across environmental conditions

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Elizabeth A Mueller ◽  
Alexander JF Egan ◽  
Eefjan Breukink ◽  
Waldemar Vollmer ◽  
Petra Anne Levin
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Growth Parameter ◽  
Culture Conditions ◽  
Cell Wall Integrity ◽  
Editorial Note ◽  
Bacterial Cells ◽  
Wide Range ◽  
Peptidoglycan Cell Wall ◽  
Wide Ph Range

Although the peptidoglycan cell wall is an essential structural and morphological feature of most bacterial cells, the extracytoplasmic enzymes involved in its synthesis are frequently dispensable under standard culture conditions. By modulating a single growth parameter—extracellular pH—we discovered a subset of these so-called ‘redundant’ enzymes in Escherichia coli are required for maximal fitness across pH environments. Among these pH specialists are the class A penicillin binding proteins PBP1a and PBP1b; defects in these enzymes attenuate growth in alkaline and acidic conditions, respectively. Genetic, biochemical, and cytological studies demonstrate that synthase activity is required for cell wall integrity across a wide pH range and influences pH-dependent changes in resistance to cell wall active antibiotics. Altogether, our findings reveal previously thought to be redundant enzymes are instead specialized for distinct environmental niches. This specialization may ensure robust growth and cell wall integrity in a wide range of conditions.Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).

Genetic engineering: possibilities and prospects for its application in industrial microbiology

1980 ◽  
Vol 290 (1040) ◽  
pp. 369-386 ◽  
Keyword(s):  
Escherichia Coli ◽  
Genetic Engineering ◽  
Detailed Analysis ◽  
Bacterial Cells ◽  
Bacterial Enzymes ◽  
Distant Future ◽  
Cells In Culture ◽  
Wide Range ◽  
Hybrid Dna

A wide range of techniques is now available for the construction of hybrid DNA molecules comprising components from disparate species. Transfer of segments of DNA from other organisms, and especially eukaryotes, to Escherichia coli permits their preparation in quantities sufficient for detailed analysis of their structure and mechanism of expression. This information could be exploited to enhance the quantity or quality of polypeptide products from bacterial cells. Greatly increased yields of bacterial enzymes have been obtained in this way in several instances. The approaches that have been pioneered with bacteria are currently being applied to higher organisms. Much work is in progress with yeasts, in which transformation has been successfully demonstrated, with animal viruses and cells in culture and with some plant systems and offers the promise of wider applications of genetic engineering in the not too distant future.

Analysis of the Crushing Effect about Ultrasound on E. coli and B. subtilis

2012 ◽  
Vol 260-261 ◽  
pp. 1017-1021
Author(s):  
Xin Ying Wang ◽  
Yong Tao Liu ◽  
Min Hui ◽  
Ji Fei Xu
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Bacillus Subtilis ◽  
Bacterial Cell ◽  
Logarithmic Phase ◽  
Growth Stages ◽  
Bacterial Cells ◽  
E Coli ◽  
Different Growth Stages ◽  
Main Factor

Escherichia coli and Bacillus subtilis as objects of the study, ultrasonic fragmentation acted on the bacterial cells in different growth stages, results showed that, it’s similar to the crushing effect of ultrasound on E. coli and B. subtilis cells of different growth stages, the highest crushing rate in the logarithmic phase, reached to 95.8% and 94.3% respectively, the crushing rate of adjustment phase is lowest, maintained at around 60%, the crushing rate stability cell was centered, which can be achieved 90%. The structure of the bacterial cell wall didn’t the main factor to decide the ultrasonic fragmentation effect, but different growth periods of bacterial cells did the determinant.

scholarly journals Simulations suggest a constrictive force is required for Gram-negative bacterial cell division

2018 ◽  
Author(s):  
Lam T. Nguyen ◽  
Catherine M. Oikonomou ◽  
H. Jane Ding ◽  
Mohammed Kaplan ◽  
Qing Yao ◽  
...  
Keyword(s):  
Cell Wall ◽  
Simulation System ◽  
Mechanistic Models ◽  
Bacterial Cells ◽  
Bacterial Cell Division ◽  
Cell Wall Synthesis ◽  
Gram Negative ◽  
Division Site ◽  
Cell Wall Remodeling ◽  
Peptidoglycan Cell Wall

AbstractTo divide, Gram-negative bacterial cells must remodel their peptidoglycan cell wall to a smaller and smaller radius at the division site, but how this process occurs remains debated. While the tubulin homolog FtsZ is thought to generate a constrictive force, it has also been proposed that cell wall remodeling alone is sufficient to drive membrane constriction, possibly via a make-before-break mechanism in which new hoops of cell wall are made inside the existing hoops (make) before bonds in the existing wall are cleaved (break). Previously, we constructed software, REMODELER 1, to simulate cell wall remodeling in rod-shaped bacteria during growth. Here, we used this software as the basis for an expanded simulation system, REMODELER 2, which we used to explore different mechanistic models of cell wall division. We found that simply organizing the cell wall synthesis complexes at the midcell was not sufficient to cause wall invagination, even with the implementation of a make-before-break mechanism. Applying a constrictive force at the midcell could drive division if the force was sufficiently large to initially constrict the midcell into a compressed state before new hoops of relaxed cell wall were incorporated between existing hoops. Adding a make-before-break mechanism could drive division with a smaller constrictive force sufficient to bring the midcell peptidoglycan into a relaxed, but not necessarily compressed, state.

scholarly journals Spatial organization of Clostridium difficile S-layer biogenesis

2018 ◽  
Author(s):  
Peter Oatley ◽  
Joseph A. Kirk ◽  
Shuwen Ma ◽  
Simon Jones ◽  
Robert P. Fagan
Keyword(s):  
Cell Wall ◽  
Clostridium Difficile ◽  
Spatial Organization ◽  
Protein A ◽  
Layer Growth ◽  
Bacterial Cells ◽  
Surface Layers ◽  
Positive Bacterium ◽  
Absolute Requirement ◽  
Peptidoglycan Cell Wall

AbstractSurface layers (S-layers) are protective protein coats which form around all archaea and most bacterial cells. Clostridium difficile is a Gram-positive bacterium with an S-layer covering its peptidoglycan cell wall. The S-layer in C. difficile is constructed mainly of S-layer protein A (SlpA), which is a key virulence factor and an absolute requirement for disease. S-layer biogenesis is a complex multi-step process, disruption of which has severe consequences for the bacterium. We examined the subcellular localization of SlpA secretion and S-layer growth; observing formation of S-layer at specific sites that coincide with cell wall synthesis, while the secretion of SlpA from the cell is relatively delocalized. We conclude that this delocalized secretion of SlpA leads to a pool of precursor in the cell wall which is available to repair openings in the S-layer formed during cell growth or following damage.

scholarly journals A MurF Inhibitor That Disrupts Cell Wall Biosynthesis in Escherichia coli

2007 ◽  
Vol 51 (12) ◽  
pp. 4420-4426 ◽  
Author(s):  
Ellen Z. Baum ◽  
Steven M. Crespo-Carbone ◽  
Alexandra Klinger ◽  
Barbara D. Foleno ◽  
Ignatius Turchi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Antibacterial Activity ◽  
Binding Assay ◽  
Pharmacophore Model ◽  
Fold Increase ◽  
Cell Wall Biosynthesis ◽  
Bacterial Cells ◽  
E Coli ◽  
Essential Enzyme

ABSTRACT MurF is an essential enzyme of bacterial cell wall biosynthesis. Few MurF inhibitors have been reported, and none have displayed measurable antibacterial activity. Through the use of a MurF binding assay, a series of 8-hydroxyquinolines that bound to the Escherichia coli enzyme and inhibited its activity was identified. To derive additional chemotypes lacking 8-hydroxyquinoline, a known chelating moiety, a pharmacophore model was constructed from the series and used to select compounds for testing in the MurF binding and enzymatic inhibition assays. Whereas the original diverse library yielded 0.01% positive compounds in the binding assay, of which 6% inhibited MurF enzymatic activity, the pharmacophore-selected set yielded 14% positive compounds, of which 37% inhibited the enzyme, suggesting that the model enriched for compounds with affinity to MurF. A 4-phenylpiperidine (4-PP) derivative identified by this process displayed antibacterial activity (MIC of 8 μg/ml against permeable E. coli) including cell lysis and a 5-log10-unit decrease in CFU. Importantly, treatment of E. coli with 4-PP resulted in a 15-fold increase in the amount of the MurF UDP-MurNAc-tripeptide substrate, and a 50% reduction in the amount of the MurF UDP-MurNAc-pentapeptide product, consistent with inhibition of the MurF enzyme within bacterial cells. Thus, 4-PP is the first reported inhibitor of the MurF enzyme that may contribute to antibacterial activity by interfering with cell wall biosynthesis.

scholarly journals THE EFFECT ON THE GENETIC APPARATUS OF THE MICROBIAL CELL OF COMPOUNDS BASED ON SUBSTITUTED 1H-INDOL-4-, 5-, 6-, 7-YLAMINES

2019 ◽  
Author(s):  
A. Maseykina ◽  
I. Stepanenko ◽  
S. Yamashkin ◽  
E. Slastnikov
Keyword(s):  
Escherichia Coli ◽  
Alkaline Phosphatase ◽  
Microbial Cell ◽  
Transcriptional Analysis ◽  
Antimicrobial Compounds ◽  
Bacterial Cells ◽  
Response Curves ◽  
Sos Induction ◽  
Sos Chromotest ◽  
Wide Range

The study of new antimicrobial compounds includes determining the mechanism of their effect on the microbial cell. As a rule, the effect of most modern synthetic antimicrobials is associated either with the suppression of DNA synthesis, or with the suppression of bacterial protein synthesis at the level of translation or transcription.There are sensitive and simple methods for screening and monitoring the potential genotoxic activity of a wide range of natural and synthetic compounds. To date, the Ames test has been widely used, based on the sensitivity of Salmonella strains to carcinogenic chemicals, although some compounds that cause Ames negative reactions could actually be carcinogenic to animals.Similarly, the SOS chromotest is an SOS transcriptional analysis that can evaluate DNA damage caused by chemical and physical mutagens. It measures the expression of a reporter gene (β-galactosidase). The β-galactosidase enzyme processes ortho-nitrophenyl galactopyranoside to form a yellow compound detected at 420 nm. Then, the induction of β-galactosidase normalizes the activity of alkaline phosphatase, an enzyme expressed constitutively by Escherichia coli. SOS chromotest is also widely used for genotoxicological studies. The answer is quick (several hours) and does not require the survival of the test strain. Dose response curves for various chemicals include a linear region. The slope of this area is taken as a measure of SOS induction.Therefore, an SOS chromotest was selected for the study, which allows one to identify the DNA-mediated effect of the studied compounds.The aim of the work was to evaluate the SOS-inducing activity of antimicrobial compounds based on substituted 1H-indol-4-, 5-, 6-, 7-ylamines.The strain Escherichia coli PQ 37 with the genotype F-thr leu his-4 pyrD thi galE lacΔU169 srl300 :: Th10 rpoB rpsL uvrA rfa trp :: Mis + sfi A :: Mud (Ar, lac) cts, Due to the presence of sfi A genes :: lac Z, lacZ β-galactosidase gene expression in strain PQ 37 is controlled by the promoter of the sfiA gene, one of the components of the E. coli SOS regulon. The indicator of the SOS-inducing activity of the studied compounds in the SOS chromotest is the activity of β-galactosidase, which evaluates the activity of active microorganisms - alkaline phosphatase, which also allows you to control the toxic effect of the studied compounds on bacterial cells.The results showed that 4,4,4-trifluoro-N-(6-methoxy-1,2,3-trimethyl-1H-indol-5-yl)-3-oxobutanamide (1), 4,4,4-trifluoro-N-(6-methyl-2-phenyl-1H-indol-5-yl)-3-oxobutanamide (2) and N-(1,5-dimethyl-2-phenyl-1H-indol-6-yl)-4,4,4-trifluoro-3-oxobutanamide (3) does not possess SOS-inducing activity in the studied concentrations. 4-Hydroxy-8-phenyl-4-(trifluoromethyl)-1,3,4,7-tetrahydro-2H-pyrrolo [2,3-h] -quinolin-2-one (4), 9-hydroxy-5-methyl-2-phenyl-9-(trifluoromethyl)-1,6,8,9-tetrahydro-7Н-pyrrolo-[2,3-f]quinolin-7-one (5), 6-hydroxy-2,3-dimethyl-6-(trifluoromethyl)-1,6,7,9-tetrahydro-8H-pyrrolo[3,2-h]quinolin-8-one (6) and 1,2,3,9-tetramethyl-6-(trifluoromethyl)-1,9-dihydro-8H-pyrrolo [3,2-h]quinolin-8-one (7) showed dose-dependent SOS-inducing activity in bactericidal concentrations. The obtained research results allowed us to identify compounds 4, 5, 6, 7, the mechanism of action of which includes exposure to DNA of a microbial cell.

scholarly journals Optical Tweezers Cause Physiological Damage to Escherichia coli and Listeria Bacteria

2008 ◽  
Vol 74 (8) ◽  
pp. 2441-2446 ◽  
Author(s):  
M. B. Rasmussen ◽  
L. B. Oddershede ◽  
H. Siegumfeldt
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Optical Tweezers ◽  
Laser Power ◽  
Fluorescent Protein ◽  
Growth Conditions ◽  
Ph Gradient ◽  
Bacterial Cells ◽  
E Coli

ABSTRACT We investigated the degree of physiological damage to bacterial cells caused by optical trapping using a 1,064-nm laser. The physiological condition of the cells was determined by their ability to maintain a pH gradient across the cell wall; healthy cells are able to maintain a pH gradient over the cell wall, whereas compromised cells are less efficient, thus giving rise to a diminished pH gradient. The pH gradient was measured by fluorescence ratio imaging microscopy by incorporating a pH-sensitive fluorescent probe, green fluorescent protein or 5(6)-carboxyfluorescein diacetate succinimidyl ester, inside the bacterial cells. We used the gram-negative species Escherichia coli and three gram-positive species, Listeria monocytogenes, Listeria innocua, and Bacillus subtilis. All cells exhibited some degree of physiological damage, but optically trapped E. coli and L. innocua cells and a subpopulation of L. monocytogenes cells, all grown with shaking, showed only a small decrease in pH gradient across the cell wall when trapped by 6 mW of laser power for 60 min. However, another subpopulation of Listeria monocytogenes cells exhibited signs of physiological damage even while trapped at 6 mW, as did B. subtilis cells. Increasing the laser power to 18 mW caused the pH gradient of both Listeria and E. coli cells to decrease within minutes. Moreover, both species of Listeria exhibited more-pronounced physiological damage when grown without shaking than was seen in cells grown with shaking, and the degree of damage is therefore also dependent on the growth conditions.

scholarly journals Humidity-Dependent Bacterial Cells Functional Morphometry Investigations Using Atomic Force Microscope

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Hike Nikiyan ◽  
Alexey Vasilchenko ◽  
Dmitry Deryabin
Keyword(s):  
Cell Wall ◽  
Relative Humidity ◽  
Morphological Properties ◽  
Wall Structure ◽  
Bacterial Cells ◽  
Wall Roughness ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Wide Range

The effect of a relative humidity (RH) in a range of 93–65% on morphological and elastic properties ofBacillus cereusandEscherichia colicells was evaluated using atomic force microscopy. It is shown that gradual dehumidification of bacteria environment has no significant effect on cell dimensional features and considerably decreases them only at 65% RH. The increasing of the bacteria cell wall roughness and elasticity occurs at the same time. Observed changes indicate that morphological properties ofB. cereusare rather stable in wide range of relative humidity, whereasE. coliare more sensitive to drying, significantly increasing roughness and stiffness parameters at RH 84% RH. It is discussed the dependence of the response features on differences in cell wall structure of gram-positive and gram-negative bacterial cells.

scholarly journals Assessment of Photodynamic Destruction of Escherichia coli O157:H7 and Listeria monocytogenes by Using ATP Bioluminescence

2003 ◽  
Vol 69 (11) ◽  
pp. 6393-6398 ◽  
Author(s):  
N. A. Romanova ◽  
L. Y. Brovko ◽  
L. Moore ◽  
E. Pometun ◽  
A. P. Savitsky ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Yeast Cells ◽  
Bacterial Cells ◽  
E Coli ◽  
Intracellular Atp ◽  
Microdilution Method ◽  
Wide Range ◽  
Atp Bioluminescence ◽  
Time Courses

ABSTRACT Antimicrobial photodynamic therapy was shown to be effective against a wide range of bacterial cells, as well as for fungi, yeasts, and viruses. It was shown previously that photodestruction of yeast cells treated with photosensitizers resulted in cell destruction and leakage of ATP. Three photosensitizers were used in this study: tetra(N-methyl-4-pyridyl)porphine tetratosylate salt (TMPyP), toluidine blue O (TBO), and methylene blue trihydrate (MB). A microdilution method was used to determine MICs of the photosensitizers against both Escherichia coli O157:H7 and Listeria monocytogenes. To evaluate the effects of photodestruction on E. coli and L. monocytogenes cells, a bioluminescence method for detection of ATP leakage and a colony-forming assay were used. All tested photosensitizers were effective for photodynamic destruction of both bacteria. The effectiveness of photosensitizers (in microgram-per-milliliter equivalents) decreased in the order TBO > MB > TMPyP for both organisms. The MICs were two- to fourfold higher for E. coli O157:H7 than for L. monocytogenes. The primary effects of all of the photosensitizers tested on live bacterial cells were a decrease in intracellular ATP and an increase in extracellular ATP, accompanied by elimination of viable cells from the sample. The time courses of photodestruction and intracellular ATP leakage were different for E. coli and L. monocytogenes. These results show that bioluminescent ATP-metry can be used for investigation of the first stages of bacterial photodestruction.

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