Roughness of the plasma membrane as an independent morphological parameter to study RBCs: A quantitative atomic force microscopy investigation

Girasole, M.; Pompeo, G.; Cricenti, A.; Congiu‐Castellano, A.; Andreola, F.; Serafino, Annalucia; Frazer, B. H.; Boumis, G.; Amiconi, Gino

doi:10.1016/j.bbamem.2007.01.014

Cited by 135 publications

(127 citation statements)

References 29 publications

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“…where, N is the total number of data points, z i is the height of the ith point, and z m is the mean height (19). Roughness values were measured over the entire bacterial cell surface on areas with a fixed size of 125 ϫ 125 nm 2 .…”

Section: Methodsmentioning

confidence: 99%

Escherichia coli Cell Surface Perturbation and Disruption Induced by Antimicrobial Peptides BP100 and pepR

Alves

Melo

Franquelim

et al. 2010

Journal of Biological Chemistry

205

213

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The potential of antimicrobial peptides (AMPs) as an alternative to conventional therapies is well recognized. Insights into the biological and biophysical properties of AMPs are thus key to understanding their mode of action. In this study, the mechanisms adopted by two AMPs in disrupting the Gram-negative Escherichia coli bacterial envelope were explored. BP100 is a short cecropin A-melittin hybrid peptide known to inhibit the growth of phytopathogenic Gram-negative bacteria. pepR, on the other hand, is a novel AMP derived from the dengue virus capsid protein. Both BP100 and pepR were found to inhibit the growth of E. coli at micromolar concentrations. Zeta potential measurements of E. coli incubated with increasing peptide concentrations allowed for the establishment of a correlation between the minimal inhibitory concentration (MIC) of each AMP and membrane surface charge neutralization. While a neutralization-mediated killing mechanism adopted by either AMP is not necessarily implied, the hypothesis that surface neutralization occurs close to MIC values was confirmed. Atomic force microscopy (AFM) was then employed to visualize the structural effect of the interaction of each AMP with the E. coli cell envelope. At their MICs, BP100 and pepR progressively destroyed the bacterial envelope, with extensive damage already occurring 2 h after peptide addition to the bacteria. A similar effect was observed for each AMP in the concentration-dependent studies. At peptide concentrations below MIC values, only minor disruptions of the bacterial surface occurred.

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Section: Methodsmentioning

confidence: 99%

Escherichia coli Cell Surface Perturbation and Disruption Induced by Antimicrobial Peptides BP100 and pepR

Alves

Melo

Franquelim

et al. 2010

Journal of Biological Chemistry

205

213

View full text Add to dashboard Cite

show abstract

“…On the other hand, previous studies demonstrated roughness values, average roughness (Ra) and root-mean-square roughness (Rq), to be markers of the degree of change to cell membranes. [44][45][46] As shown in Figure 4B and C, both the Ra and Rq of two different areas increased in a dose-and time-dependent manner. The Ra and Rq values of the cells in the control group were low, indicating a smooth surface ( Figure 4A).…”

mentioning

confidence: 76%

Effect of dacarbazine on CD44 in live melanoma cells as measured by atomic force microscopy-based nanoscopy

Huang

Zhang

et al. 2017

IJN

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CD44 ligand–receptor interactions are known to be involved in regulating cell migration and tumor cell metastasis. High expression levels of CD44 correlate with a poor prognosis of melanoma patients. In order to understand not only the mechanistic basis for dacarbazine (DTIC)-based melanoma treatment but also the reason for the poor prognosis of melanoma patients treated with DTIC, dynamic force spectroscopy was used to structurally map single native CD44-coupled receptors on the surface of melanoma cells. The effect of DTIC treatment was quantified by the dynamic binding strength and the ligand-binding free-energy landscape. The results demonstrated no obvious effect of DTIC on the unbinding force between CD44 ligand and its receptor, even when the CD44 nanodomains were reduced significantly. However, DTIC did perturb the kinetic and thermodynamic interactions of the CD44 ligand–receptor, with a resultant greater dissociation rate, lower affinity, lower binding free energy, and a narrower energy valley for the free-energy landscape. For cells treated with 25 and 75 μg/mL DTIC for 24 hours, the dissociation constant for CD44 increased 9- and 70-fold, respectively. The CD44 ligand binding free energy decreased from 9.94 for untreated cells to 8.65 and 7.39 kcal/mol for DTIC-treated cells, which indicated that the CD44 ligand–receptor complexes on DTIC-treated melanoma cells were less stable than on untreated cells. However, affinity remained in the micromolar range, rather than the millimolar range associated with nonaffinity ligands. Hence, the CD44 receptor could still be activated, resulting in intracellular signaling that could trigger a cellular response. These results demonstrate DTIC perturbs, but not completely inhibits, the binding of CD44 ligand to membrane receptors, suggesting a basis for the poor prognosis associated with DTIC treatment of melanoma. Overall, atomic force microscopy-based nanoscopic methods offer thermodynamic and kinetic insight into the effect of DTIC on the CD44 ligand-binding process.

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“…This challenge is seen both at the cellular and humoral levels involving white blood cells and their significant roles in the wound healing of diabetic rats administered sildenafil citrate (Tas et al, 2011). This study which involves analysis of red blood cells count in diabetic rats with wound formation following treatment with sildenafil citrate is of significance because wound healing also depend on oxygenation which is supplied to the bodily parts via hemoglobin in the circulating red blood cells (Girasole et al, 2007;Hamed et al, 2010). The roles of nitric oxide in the regulation of vasodilation (Furchgott, 1996), control of the cell cycling and apoptosis, cell proliferation and differentiation (Weller et al, 1998) have been described in previous studies.…”

Section: Introductionmentioning

confidence: 95%

Haematological changes and wound healing effects of sildenafil citrate in diabetic albino rats

Mahre¹,

Umaru²,

Ngulde³

et al. 2017

Sokoto J. Vet. Sc.

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This study presents baseline data on the effect of sildenafil citrate on some of the haematological and biochemical parameters in wistar rats with diabetes and wound formation. Forty two albino rats weighing between 139 and 225 g were separated at random into seven groups (A, B, C, D, E, F and G) of six rats per group. Type 1 diabetes mellitus was induced in groups A, B, C and D by a single intra-peritoneal injection of 130 mg/kg Alloxan. Rats in group A were treated with orally dose of 50 mg/kg sildenafil citrate for 21 days and rats in group B were administered 10 IU of insulin intramuscularly once and sildenafil citrate as in Group A. The rats in group C were treated with a single dose of 10 IU of insulin intramuscularly, and rats in group D with only distilled water. Groups E and F were normal rats with wounds similar to those of diabetic rats in the previous groups and each rat in group E was also treated with sildenafil citrate as in Group A and those in group F were treated with only distilled water. Group G were normal rats without wound treated with sildenafil citrate as in Group A. Blood samples were taken before (day 0) and after the administration of the sildenafil citrate on day 7, 14 and 21. The results of the study showed significant decreased in red blood cells count from 6.28 ± 0.46 × 10 6 to 2.81 ± 0.46 × 10 6 in diabetic rats during the 14 days of treatment with sildenafil citrate, however, there was an indication that continues treatment for up to 21 days reduced the blood glucose and increased the red blood cells count and this may be an indication that sildenafil citrate improves insulin mediated glucose pathways.

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Roughness of the plasma membrane as an independent morphological parameter to study RBCs: A quantitative atomic force microscopy investigation

Cited by 135 publications

References 29 publications

Escherichia coli Cell Surface Perturbation and Disruption Induced by Antimicrobial Peptides BP100 and pepR

Escherichia coli Cell Surface Perturbation and Disruption Induced by Antimicrobial Peptides BP100 and pepR

Effect of dacarbazine on CD44 in live melanoma cells as measured by atomic force microscopy-based nanoscopy

Haematological changes and wound healing effects of sildenafil citrate in diabetic albino rats

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