BACKGROUND: In a previous study of the properties of red blood cells (RBC) trapped in an optical tweezers trap, an increase in the spectrum of Brownian fluctuations for RBCs from a Plasmodium falciparum culture (due to increased rigidity) compared with normal RBCs was measured. A bystander effect was observed, whereby RBCs actually hosting the parasite had an effect on the physical properties of remaining non-hosting RBCs. METHODS: The distribution of corner frequency (fc) in the power spectrum of single RBCs held in an optical tweezers trap was studied. Two tests were done to confirm the bystander effect. In the first, RBCs from an infected culture were separated into hosting and non-hosting RBCs. In the second, all RBCs were removed from the infected culture, and normal RBCs were incubated in the spent medium. The trapping environment was the same for all measurements so only changes in the properties of RBCs were measured. RESULTS: In the first experiment, a similar and statistically significant increase was measured both for hosting and non-hosting RBCs. In the second experiment, normal RBCs incubated in spent medium started to become rigid after a few hours and showed complete changes (comparable with RBCs from the infected culture) after 24 h. CONCLUSION: These experiments provide direct evidence of medium-induced changes in the properties of RBCs in an infected culture, regardless of whether the RBCs actually host the parasite.
BACKGROUND: In a previous study of the properties of red blood cells (RBC) trapped in an optical tweezers trap, an increase in the spectrum of Brownian fluctuations for RBCs from a Plasmodium falciparum culture (due to increased rigidity) compared with normal RBCs was measured. A bystander effect was observed, whereby RBCs actually hosting the parasite had an effect on the physical properties of remaining non-hosting RBCs. METHODS: The distribution of corner frequency (fc) in the power spectrum of single RBCs held in an optical tweezers trap was studied. Two tests were done to confirm the bystander effect. In the first, RBCs from an infected culture were separated into hosting and non-hosting RBCs. In the second, all RBCs were removed from the infected culture, and normal RBCs were incubated in the spent medium. The trapping environment was the same for all measurements so only changes in the properties of RBCs were measured. RESULTS: In the first experiment, a similar and statistically significant increase was measured both for hosting and non-hosting RBCs. In the second experiment, normal RBCs incubated in spent medium started to become rigid after a few hours and showed complete changes (comparable with RBCs from the infected culture) after 24 h. CONCLUSION: These experiments provide direct evidence of medium-induced changes in the properties of RBCs in an infected culture, regardless of whether the RBCs actually host the parasite.
Authors: Paulo R R Totino; Cláudio T Daniel-Ribeiro; Maria de Fátima Ferreira-da-Cruz Journal: Front Cell Infect Microbiol Date: 2016-12-09 Impact factor: 5.293
Authors: Nicole Toepfner; Christoph Herold; Oliver Otto; Philipp Rosendahl; Angela Jacobi; Martin Kräter; Julia Stächele; Leonhard Menschner; Maik Herbig; Laura Ciuffreda; Lisa Ranford-Cartwright; Michal Grzybek; Ünal Coskun; Elisabeth Reithuber; Geneviève Garriss; Peter Mellroth; Birgitta Henriques-Normark; Nicola Tregay; Meinolf Suttorp; Martin Bornhäuser; Edwin R Chilvers; Reinhard Berner; Jochen Guck Journal: Elife Date: 2018-01-13 Impact factor: 8.140