Effect of Direct Current Electric Fields on Cone Like Retinal Photoreceptor Cells.

Introduction: Studies show that electric fields are used as therapy during nerve and tissue injuries along with trans-retinal stimulation. However, cellular and molecular changes induced by such treatments remain largely unknown especially in retinal photoreceptor cells. studies show that direct current electric fields (dcEF) were known to influence cell division, polarity, shape, and motility.

Comparison between mouse and sea urchin orthologs of voltage-gated proton channel suggests role of S3 segment in activation gating.

The voltage-gated proton channel, Hv1, is expressed in blood cells, airway epithelium, sperm and microglia, playing important roles in diverse biological contexts including phagocytosis or sperm maturation through its regulation of membrane potential and pH. The gene encoding Hv1, HVCN1, is widely found across many species and is also conserved in unicellular organisms such as algae or dinoflagellates where Hv1 plays role in calcification or bioluminescence. Voltage-gated proton channels exhibit a large variation of activation rate among different species.

NHE3 phosphorylation via PKCη marks the polarity and orientation of directionally migrating cells.

Endogenous electric fields (EF) may provide an overriding cue for directional cell migration during wound closure. Perceiving a constant direction requires active sodium-hydrogen exchanger (pNHE3) at the leading edge of HEK 293 cells but its activation mechanism is not yet fully understood. Because protein kinase C (PKC) is required in electrotaxis, we asked whether NHE3 is activated by PKC during wound healing.

Phospho-NHE3 forms membrane patches and interacts with beta-actin to sense and maintain constant direction during cell migration.

The Na(+)/H(+) exchanger NHE3 colocalizes with beta-actin at the leading edge of directionally migrating cells. Using human osteosarcoma cells (SaOS-2), rat osteoblasts (calvaria), and human embryonic kidney (HEK) cells, we identified a novel role for NHE3 via beta-actin in anode and cathode directed motility, during electrotaxis. NHE3 knockdown by RNAi revealed that NHE3 expression is required to achieve constant directionality and polarity in migrating cells.

Correlative light and electron microscopy of intermediate stages of meiotic spindle assembly in the early Caenorhabditis elegans embryo.

This chapter is an update of the previously published book chapter "Correlative Light and Electron Microscopy of Early C. elegans Embryos in Mitosis" (Müller-Reichert, Srayko, Hyman, O'Toole, & McDonald, 2007). Here, we have adapted and improved the protocol for the isolated meiotic embryos, which was necessary to meet the specific challenges a researcher faces while investigating the development of very early Caenorhabditis elegans embryos ex-utero.

Three-dimensional reconstruction methods for Caenorhabditis elegans ultrastructure.

The roundworm Caenorhabditis elegans is one of the major model organisms in modern cell and developmental biology. Here, we present methods for the three-dimensional (3D) reconstruction of the worm ultrastructure. We describe the use of (1) serial-section analysis, (2) electron tomography, and (3) serial block face imaging by scanning electron microscopy (SEM).

The elegans of spindle assembly.

The Caenorhabditis elegans one-cell embryo is a powerful system in which to study microtubule organization because this large cell assembles both meiotic and mitotic spindles within the same cytoplasm over the course of 1 h in a stereotypical manner. The fertilized oocyte assembles two consecutive acentrosomal meiotic spindles that function to reduce the replicated maternal diploid set of chromosomes to a single-copy haploid set. The resulting maternal DNA then unites with the paternal DNA to form a zygotic diploid complement, around which a centrosome-based mitotic spindle forms.

Characteristics of highly flexible PDMS membranes for long-term mechanostimulation of biological tissue.

Measurement of mechanical properties of soft biological tissue remains a challenging task in mechanobiology. Recently, we presented a bioreactor for simultaneous mechanostimulation and analysis of the mechanical properties of soft biological tissue samples. In this bioreactor, the sample is stretched via deflection of a flexible membrane.