C-type inactivation of potassium channels fine-tunes the electrical signaling in excitable cells through an internal timing mechanism that is mediated by a hydrogen bond network in the channels' selectively filter. Previously, we used nonsense suppression to highlight the role of the conserved Trp434-Asp447 indole hydrogen bond in Shaker potassium channels with a non-hydrogen bonding homologue ...

Sadeq H. Bakhy, Shaker S. Hassan, Somer M. Nacy, K. Dermitzakis and Alejandro Hernandez Arieta Robotica / Volume 31 / Issue 04 / July 2013, pp 599 ­ 609 DOI: 10.1017/S0263574712000653, Published online: 31 October 2012 Link to this article: http://journals.cambridge.org/abstract_S0263574712000653 How to cite this article: Sadeq H. Bakhy, Shaker S. Hassan, Somer M. Nacy, K. Dermitzakis and Aleja...

We sought to determine the contribution of an individual voltage sensor to Shaker's function. Concatenated heterotetramers of Shaker zH4 Delta(6-46) wild type (wt) in combination with a neutral S4 segment Shaker mutant (mut) with stoichiometries 2wt/2mut and 1wt/3mut were studied and compared with the 4wt concatenated homotetramer. A single charged voltage sensor is sufficient to open Shaker co...

Electrodynamic shakers are widely used in experimental investigations of vibrated fluids and granular materials. However, they are plagued by undesirable internal resonances that can significantly impact the quality of vibration. In this work, we measure the performance of a typical shaker and characterize the influence that a payload has on its developed by Goldman (2002) [1] which consists of...

Dihydropyridines (DHPs) are well known for their effects on L-typed voltage-dependent Ca2+ channels, However, these drugs also affect other voltage-dependent ion channels, including Shaker K+ channels. We examined the effects of DHPs on the Shaker K+ channels expressed in Xenopus oocytes. Intracellular applications of DHPs quickly and reversibly induced apparent inactivation in the Shaker K+ mu...

Three new toxins from the venom of the scorpion Leiurus quinquestriatus var. hebraeus have been identified on the basis of their ability to block the Shaker K+ channel. These toxins have been purified using HPLC techniques and characterized as 38 amino acid peptides by mass spectroscopy, amino acid analysis, and sequence determination. Their chemical identity was confirmed by producing fully fu...

Increased neuronal activity (eag Shaker mutants) and cAMP concentration (dunce mutants) lead to increased synaptic structure and function at the Drosophila neuromuscular junction. Here, we show that the increase in synaptic growth is accompanied by an approximately 50% decrease in synaptic levels of the cell adhesion molecule Fasciclin II (Fas II). This decrease in Fas II is both necessary and ...

Milled rice from a laboratory mill and a commercial–scale mill was evaluated for head rice yield using a shaker table and a machine–vision system called the GrainCheck. Comparisons were made for both medium– and long–grain rice varieties. For each variety, samples with different levels of broken kernels were analyzed to determine the performance of the two instruments over a range of head rice ...

The Drosophila neuromuscular junction (NMJ) ranks as one of the preeminent model systems for studying synaptic development, function, and plasticity. This protocol describes the use of the two-electrode voltage clamp (TEVC) to examine potassium (K(+)) currents mediated by voltage-gated ion channels, and gives several genetic and pharmacological methods that are used to study the currents. Droso...

We describe the in situ modulation of potassium channels in a semi-intact preparation of the Drosophila retina. In whole-cell recordings of photoreceptors, rapidly inactivating Shaker channels are characterized by a conspicuously negative voltage operating range; together with a delayed rectifier, these channels are specifically modulated by the putative efferent neurotransmitter serotonin. Con...