Open Access. Powered by Scholars. Published by Universities.®
Biochemistry, Biophysics, and Structural Biology Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Publication Type
Articles 1 - 5 of 5
Full-Text Articles in Biochemistry, Biophysics, and Structural Biology
Loading Peptides Into Dictyostelium Discoideum Using Pinocytosis, Electroporation, Cell Penetrating Peptides, And Myristoylation, Lorena Lazo De La Vega
Loading Peptides Into Dictyostelium Discoideum Using Pinocytosis, Electroporation, Cell Penetrating Peptides, And Myristoylation, Lorena Lazo De La Vega
Senior Theses and Projects
The phospholipid bilayer of the cell is fluid and allows transport of small, hydrophobic compounds across the membrane. However, larger molecules such as peptides cannot cross the bilayer as easily. Therefore, my goal is to identify and optimize a method for loading exogenous peptides, such as reporters, hormones, or drugs, through the cell membrane. For these studies, we are using Dictyostelium discoideum as a model organism to test four peptide loading methods: pinocytosis, electroporation, cell-penetrating peptides and myristoylation. Pinocytosis uses changes in osmotic pressure to load the peptides through vesicles. The cells were exposed to a hypertonic solution for 10 …
Cellular Regulation Of Extension And Retraction Of Pseudopod-Like Blebs Produced By Nanosecond Pulsed Electric Field, Mikhail A. Rassokhin, Andrei G. Pakhomov
Cellular Regulation Of Extension And Retraction Of Pseudopod-Like Blebs Produced By Nanosecond Pulsed Electric Field, Mikhail A. Rassokhin, Andrei G. Pakhomov
Bioelectrics Publications
Recently we described a new phenomenon of anodotropic pseudopod-like blebbing in U937 cells exposed to nanosecond pulsed electric field (nsPEF). In Ca2+ -free buffer such exposure initiates formation of pseudopod-like blebs (PLBs), protrusive cylindrical cell extensions that are distinct from apoptotic and necrotic blebs. PLBs nucleate predominantly on anode-facing cell pole and extend toward anode during nsPEF exposure. Bleb extension depends on actin polymerization and availability of actin monomers. Inhibition of intracellular Ca2+ , cell contractility, and RhoA produced no effect on PLB initiation. Meanwhile, inhibition of WASP by wiskostatin causes dose-dependent suppression of PLB growth. Soon after …
Disassembly Of Actin Structures By Nanosecond Pulsed Electric Field Is A Downstream Effect Of Cell Swelling, Andrei G. Pakhomov, Shu Xiao, Olga N. Pakhomova, Iurii Semenov, Marjorie A. Kuipers, Bennett L. Ibey
Disassembly Of Actin Structures By Nanosecond Pulsed Electric Field Is A Downstream Effect Of Cell Swelling, Andrei G. Pakhomov, Shu Xiao, Olga N. Pakhomova, Iurii Semenov, Marjorie A. Kuipers, Bennett L. Ibey
Bioelectrics Publications
Disruption of the actin cytoskeleton structures was reported as one of the characteristic effects of nanosecond-duration pulsed electric field (nsPEF) in both mammalian and plant cells. We utilized CHO cells that expressed the monomeric fluorescent protein (mApple) tagged to actin to test if nsPEF modifies the cell actin directly or as a consequence of cell membrane permeabilization. A train of four 600-ns pulses at 19.2 kV/cm (2 Hz) caused immediate cell membrane poration manifested by YO-PRO-1 dye uptake, gradual cell rounding and swelling. Concurrently, bright actin features were replaced by dimmer and uniform fluorescence of diffuse actin. To block the …
Cancellation Of Cellular Responses To Nanoelectroporation By Reversing The Stimulus Polarity, Andrei G. Pakhomov, Iurii Semenov, Shu Xiao, Olga N. Pakhomova, Betsy Gregory, Karl H. Schoenbach
Cancellation Of Cellular Responses To Nanoelectroporation By Reversing The Stimulus Polarity, Andrei G. Pakhomov, Iurii Semenov, Shu Xiao, Olga N. Pakhomova, Betsy Gregory, Karl H. Schoenbach
Bioelectrics Publications
Nanoelectroporation of biomembranes is an effect of high-voltage, nanosecond-duration electric pulses (nsEP). It occurs both in the plasma membrane and inside the cell, and nanoporated membranes are distinguished by ion-selective and potential-sensitive permeability. Here we report a novel phenomenon of bioeffects cancellation that puts nsEP cardinally apart from the conventional electroporation and electrostimulation by milli- and microsecond pulses. We compared the effects of 60- and 300-ns monopolar, nearly rectangular nsEP on intracellular Ca2+mobilization and cell survival with those of bipolar 60 + 60 and 300 + 300 ns pulses. For diverse endpoints, exposure conditions, pulse numbers (1-60), and …
Calcium-Mediated Pore Expansion And Cell Death Following Nanoelectroporation, Olga N. Pakhomova, Betsy Gregory, Iurii Semenov, Andrei G. Pakhomov
Calcium-Mediated Pore Expansion And Cell Death Following Nanoelectroporation, Olga N. Pakhomova, Betsy Gregory, Iurii Semenov, Andrei G. Pakhomov
Bioelectrics Publications
Opening of long-lived pores in the cell membrane is the principal primary effect of intense, nanosecond pulsed electric field (nsPEF). Here we demonstrate that the evolution of pores, cell survival, the time and the mode of cell death (necrotic or apoptotic) are determined by the level of external Ca2+ after nsPEF. We also introduce a novel, minimally disruptive technique for nsEP exposure of adherent cells on indium tin oxide (ITO)-coated glass coverslips, which does not require cell detachment and enables fast exchanges of bath media. Increasing the Ca2+ level from the nominal 2–5 μM to 2 mM for …