Bacterial Cell Mechanics

Auer, George K.; Weibel, Douglas B.

doi:10.1021/acs.biochem.7b00346

Cited by 182 publications

(148 citation statements)

References 132 publications

(322 reference statements)

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“…These results are to be expected, since the membranes of Gram-positive bacteria are more susceptible to the action of antimicrobial agents. [9] A previous study [2] showed that the EO obtained from the pericarp and the leaves of I. juruensis were active against E. coli and against C. albicans, while in the present study, the EOs from I. polyneura were not effective against the same species of the yeast. Also, the same study [2] revealed a lack of antibacterial activity of the EOs from the pericarp and the leaves of I. juruensis against P. aeruginosa, which are results consistent with those reported in this study.…”

Section: Resultscontrasting

confidence: 54%

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Interference of Seasonal Variation on the Antimicrobial and Cytotoxic Activities of the Essential Oils from the Leaves of Iryanthera polyneura in the Amazon Rain Forest

Martins¹,

Díaz

Paciência³

et al. 2019

Chemistry & Biodiversity

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The essential oils (EOs) obtained from the leaves of Iryanthera polyneura Ducke trees was chemically Assessed and tested for the ability of inhibiting the growth of Candida albicans, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans and S. sanguinis. The oil was also tested against breast (MCF‐7) and prostate (PC‐3) cancer cell lines. Minimum bactericidal concentrations (MBCs) and 50 % inhibition concentrations (IC50) values were obtained. EOs were active against Gram‐positive bacteria. Spathulenol, α‐cadinol and τ‐muurolol were major components of EOs. The oils showed a higher cytotoxicity against PC‐3 than MCF‐7 cells, although the oils were active against both cell types. Oils obtained from leaves collected in the dry season were more active against E. faecalis, S. aureus and PC‐3, while the oils obtained from leaves collected in the rainy season were more active against S. mutans, S. sanguinis and MCF‐7. The antibacterial and cytotoxic activities of the essential oils from the leaves of I. polyneura are related to the seasonal climate variation and are influenced by compounds that are minor components of the oils.

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Section: Resultscontrasting

confidence: 54%

“…The oils were more efficient against the Gram‐positive Enterococcus faecalis , Staphylococcus aureus and Streptococcus mutans . These results are to be expected, since the membranes of Gram‐positive bacteria are more susceptible to the action of antimicrobial agents …”

Section: Resultsmentioning

confidence: 77%

Interference of Seasonal Variation on the Antimicrobial and Cytotoxic Activities of the Essential Oils from the Leaves of Iryanthera polyneura in the Amazon Rain Forest

Martins¹,

Díaz

Paciência³

et al. 2019

Chemistry & Biodiversity

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“…Bacterial cell mechanics is generally attributed to the peptidoglycan (PG) layer of the cell wall, which has a thickness of ∼3-50 nm and surrounds the cytoplasmic membrane (11). Very little is known about mechanical regulation in bacteria (12–17) and we are unaware of studies connecting swarming to changes in cell mechanics. We quantified changes in swarmer-cell stiffness using cell-bending assays in a reloadable, poly(dimethylsiloxane) microfluidic system (Fig.…”

Section: Resultsmentioning

confidence: 99%

Bacterial swarming reducesProteus mirabilisandVibrio parahaemolyticuscell stiffness and increases β-lactam susceptibility

Auer¹,

Oliver

Rajendram

et al. 2018

Preprint

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1Swarmer cells of the gram-negative uropathogenic bacteria Proteus mirabilis and Vibrio 2 parahaemolyticus become long (>10-100 µm) and multinucleate during their growth and 3 motility on polymer surfaces. We demonstrate increasing cell length is accompanied by 4 a large increase in flexibility. Using a microfluidic assay to measure single-cell 5 mechanics, we identified large differences in swarmer cell stiffness of (bending rigidity 6 of P. mirabilis, 9.6 x 10 -22 N m 2 ; V. parahaemolyticus, 9.7 x 10 -23 N m 2 ) compared to 7 vegetative cells (1.4 x 10 -20 N m 2 and 3.2 x 10 -22 N m 2 , respectively). The reduction in 8 bending rigidity (~3-24 fold) was accompanied by a decrease in the average 9 polysaccharide strand length of the peptidoglycan layer of the cell wall from 28-30 to 10 19-22 disaccharides. Atomic force microscopy revealed a reduction in P. mirabilis 11 peptidoglycan thickness from 1.5 nm (vegetative) to 1.0 nm (swarmer) and electron 12 cryotomography indicated changes in swarmer cell wall morphology. P. mirabilis and V. 13 parahaemolyticus swarmer cells became increasingly sensitive to osmotic pressure and 14 susceptible to cell wall-modifying antibiotics (compared to vegetative cells)-they were 15 ~30% more likely to die after 3 h of treatment with minimum inhibitory concentrations 16 of the β-lactams cephalexin and penicillin G. The adaptive cost of swarming is offset by 17 the increase in cell susceptibility to physical and chemical changes in their environment, 18 thereby suggesting the development of new chemotherapies for bacteria that leverage 19 swarming for the colonization of hosts and survival. 20 Importance 1Proteus mirabilis and Vibrio parahaemolyticus are bacteria that infect humans. To adapt to 2 environmental changes, these bacteria alter their cell morphology and move collectively 3 to access new sources of nutrients in a process referred to as 'swarming'. We found that 4 a change in the composition and thickness of the peptidoglycan layer of the cell wall 5 makes swarmer cells of P. mirabilis and V. parahaemolyticus more flexible (i.e., reduced 6 cell stiffness) and increases their sensitivity to osmotic pressure and cell-wall targeting 7 antibiotics (e.g., β-lactams). These results highlight the importance of assessing the 8 extracellular environment in determining antibiotic doses and the use of β-lactams 9 antibiotics for treating infections caused by swarmer cells of P. mirabilis and V. 10 parahaemolyticus. 11 12 13 14 15 16 17 18 19 20

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“…However, Pa was submitted to 8 times the MIC of 2h, the growth was suppressed until 12 h and then the regrowth occurred. This regrowth was attributed to adaptation, 47,48) because the doubling rate of the cell collected after 24 h in the experiment of 8 times MIC of 2h was the same as that for the growth curve when the same experiment was repeated at 8 times MIC of 2h. This bacterial regrowth was not observed for AgNO 3 .…”

mentioning

confidence: 99%

Synthesis and Antimicrobial Activity of 2-Trifluoroacetonylbenzoxazole Ligands and Their Metal Complexes

Watanabe

Sekiya

Tamai

et al. 2018

CHEMICAL & PHARMACEUTICAL BULLETIN

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Key words antibacterial activity; fluorinated benzoxazole; metal complex; trifluoroacetylBacterial infection remains a serious threat to human lives due to rapid development of resistance to the existing antibiotics. In order to prevent this major medical problem, the discovery of new types of antimicrobial agents is a very important but challenging task.1,2) Transition metal complexes have received great attention because many drugs such as antibiotics and quinolone antibiotics possess better pharmaceutical properties when they are in the form of metal complexes. 3-7)Benzoxazole heterocycle system is an important pharmacophore and privileged structure in the medicinal chemistry. 8-10)Its derivatives and particularly, 2-substituted benzoxazoles exert various biological activities such as antimicrobial, antiviral, antifungal, and anticancer. [11][12][13][14][15] In previous studies, we have identified 2-trifluoroacetonylbenzoxazole (1a) with in vitro antimicrobial activity against Helicobacter pylori and Escherichia coli (Ec) from our compound library of trifluoromethyl ketones obtained by our developed reactions. 16,17) The heteroaryl-substituted alkenol systems such as 1a are known to chelate some metal ions such as aluminum 18) and to form a stable six-membered metal complexes in a bidentate mode, where the complexes were reinforced by a positive inductive effect of the heterocyclic moiety and a negative inductive effect of the CF 3 groups. [19][20][21][22][23] In the light of these knowledge, three 2-fluoroacetonylbenzoxazole ligands 1a-c and their new Zn(II) complexes 2a-c have been synthesized in order to check how the metal ion binding may influence their antibacterial activity (Chart 1). In addition, syntheses of new metal [Mg(II), Ni(II), Cu(II), Pd(II), and Ag(I)] complexes 2d-h from 1a have been also described ( Table 1). The structures of six metal complexes 2b and 2d-h were determined by single-crystal X-ray diffraction analyses. In vitro antimicrobial activities of the ligands 1a-c and their metal complexes 2a-h were investigated against six Gram-positive (G(+)) and six Gram-negative (G(−)) bacteria and the results were compared with those of silver nitrate and appropriate antibiotics such as Kanamycin, Gentamicin, Norfloxacin, and/or Linezolid. The most potent Ag(I) complex 2h is bacteriostatic, disrupts membrane integrity observed by scanning electron microscopy (SEM) and is less likely to develop resistance development against Pseudomonas aeruginosa (Pa). Results and DiscussionChemistry First, three benzoxazole ligands 1a-c and their new Zn(II) complexes 2a-c have been prepared in order to investigate the relationship of the ligands and their Zn(II) complexes with their antibacterial activities.Our synthetic protocol to obtain the ligand 1a consists of a trifluoroacetylation of 2-methylbenzoxazole with trifluoroacetic anhydride (TFAA) in the presence of pyridine 24) (Chart 1). The Zn(II) complex 2a was prepared by the reaction of 1a with zinc dust in MeCN in 78% yield, consisting of 1a with zinc(...

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Bacterial Cell Mechanics

Cited by 182 publications

References 132 publications

Interference of Seasonal Variation on the Antimicrobial and Cytotoxic Activities of the Essential Oils from the Leaves of Iryanthera polyneura in the Amazon Rain Forest

Interference of Seasonal Variation on the Antimicrobial and Cytotoxic Activities of the Essential Oils from the Leaves of Iryanthera polyneura in the Amazon Rain Forest

Bacterial swarming reducesProteus mirabilisandVibrio parahaemolyticuscell stiffness and increases β-lactam susceptibility

Synthesis and Antimicrobial Activity of 2-Trifluoroacetonylbenzoxazole Ligands and Their Metal Complexes

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