We have used the patch-clamp electrical recording technique on giant spheroplasts of Escherichia coli and discovered pressure-activated ion channels. The channels following properties: activation by slight positive or negative pressure; voltage dependence; large conductance; selectivity for anions over cations; dependence activity species permeant ions. believe that these may be involved in bacterial osmoregulation osmotaxis.

Previous ERP studies have often reported two components—LAN and P600—in response to subject-verb (S-V) agreement violations (e.g., the boys *runs). However, latency, amplitude scalp distribution of these components been shown vary depending on various experiment-related factors. One factor that has not received attention is extent which relative perceptual salience related either utterance position (verbal inflection in utterance-medial vs. utterance-final contexts) or type violation (errors...

As a first step in the biochemical analysis of membrane excitation wild-type Paramecium and its behavioral mutants we have defined protein composition ciliary cells. The techniques for isolation cilia vesicles were refined. Membranes high purity integrity obtained without use detergents. fractions characterized by electron microscopy, proteins whole cilia, axonemes, resolved SDS polyacrylamide gel electrophoresis isoelectric focusing one two dimensions. Protein patterns EM appearance highly...

MscL is a channel that opens large pore in the Escherichia coli cytoplasmic membrane response to mechanical stress. Previously, we highly enriched protein by using patch clamp as functional assay and cloned corresponding gene. The predicted contains largely hydrophobic core spanning two-thirds of molecule more hydrophilic carboxyl terminal tail. Because had no homology characterized proteins, it was impossible predict regions simple inspection. Here, mutagenesis, have searched for...

The COT1 gene of Saccharomyces cerevisiae has been isolated as a dosage-dependent suppressor cobalt toxicity. Overexpression the confers increased tolerance to and rhodium ions but not other divalent cations. Strains containing null alleles are viable yet more sensitive than wild-type strains. Transcription responds minimally extracellular concentration. Addition growth media results in twofold increase mRNA abundance. encodes 48-kDa protein which is found mitochondrial membrane fractions...

We report the isolation of an essential pair Saccharomyces cerevisiae genes that encode protein kinase homologues. The two were independently isolated as dosage-dependent suppressors. Increased dosage YCK1 suppressed defects caused by reduced SNF1 activity, and increased YCK2 relieved sensitivity wild-type cells to salt stress. function identically in growth assays, loss either gene alone has no discernible effect on growth. However, both results inviability. predicted products share 77%...

The patch-clamp technique was used to examine the plasma membranes of sensitive yeast spheroplasts exposed partially purified killer toxin preparations. Asolectin liposomes in which incorporated were also examined. Excised inside-out patches from these preparations often revealed at 118 pS conductance appearing pairs. current through this flickered rapidly among three states: dwelling mostly unit-open state, less frequently two-unit-open and more rarely closed state. Membrane voltages -80 80...

The orientation and configuration of the central-pair microtubules in cilia were studied by serial thin-section analysis "instantaneously fixed" paramecia. Cilia frozen various positions metachronal waves such a fixation. spatial sequence these across wave represents temporal during active beat cycle cilium. Systematic shifts indicate that central pair rotates 360 degrees counterclockwise (viewed from outside) with each ciliary (C. K. Omoto, 1979, Thesis, University Wisconsin, Madison; C....

The morphology of the transition zone between terminal plate basal body and 9 + 2 region somatic (non-oral) cilium has been examined in Paramecium tetraurelia. Freeze-fracture thin-section techniques disclosed both membrane specializations various internal structural linkages. material revealed sets particles interrupting unit membrane. more distal these form plaquelike arrays while proximal set forms ciliary "necklace." plaque regions correspond to anionic sites on outer surface as by...

Two mutants of Paramecium tetraurelia, called "pantophobiacs," were found to lack most the slow Ca2+-induced K+ outward current. Passive properties, transient Ca2+ inward current, and fast depolarization-induced current remain normal. The mutant defect reduces ability shut off a normal, excited state membrane results in repeated, long backward swimming instead wild-type jerks response variety ions, heat, touch.

Abstract The crystal structure of calmodulin (CaM; M r 16, 700, 148 residues) from the ciliated protozoan Paramecium tetraurelia (PCaM) has been determined and refined using 1.8 Å resolution area detector data. crystals are triclinic, space group P1, a = 29.66, b 53.79, c 25.49 Å, α 92.84, β 97.02, γ 88.54° with one molecule in unit cell. Crystals mammalian CaM (MCaM; Babu et al., 1988) Drosophila (DCaM; Taylor 1991) also belong to same very similar cell dimensions. All three CaMs have...

We have developed a procedure to isolate the ciliary membranes of Paramecium and analysed membrane proteins by electrophoresis on polyacrylamide gels containing either Triton X-100 or sodium dodecyl sulphate. The electrophoretic pattern sulphate showed 12-15 minor bands mol.wt. 25 000-150 000 major band 200 000-300 that contained approximately three-quarters total protein. 2. present evidence protein is related to, but not identical with, immobilization antigen (i-antigen), which large (250...

Recent ERP research with adults has shown that the online processing of subject-verb (S-V) agreement violations is mediated by relative perceptual salience violation (Dube et al. 2016). These findings corroborate infant perception research, which also influences infants' sensitivity to grammatical (Sundara, Demuth & Kuhl 2011). This raises possibility similar effects may manifest in school-aged children. To investigate this possibility, we recorded ERPs while 9–11-year-old English-speaking...

Metal ion requirements for the proliferation of Saccharomyces cerevisiae were investigated. We used bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA), a relatively tolerant chelator, to reduce free metal concentrations in culture media. Chelatable ions added back individually and combination. In addition requirement approximately 10 pM external Zn2+ we found an interchangeable either 66 nM Ca2+ or only 130 Mn2+. Cells depleted Mn2+ arrested as viable cells with 2 N nuclei tended...

Hyperpolarization of Paramecium tetraurelia under conditions where K+ currents are suppressed elicits an inward current that activates rapidly toward a peak at 25-80 ms and decays thereafter. This (Ihyp) is not affected by removing Cl ions from the microelectrodes used to clamp membrane potential, or changing extracellular Cl- concentration, but lost upon Ca2+. Ihyp also replacing Ca2+ with equimolar concentrations Ba2+, Co2+, Mg2+, Mn2+, Sr2+, suggesting permeability mechanism mediates...

The Paramecium mutant, pantophobiac A, has a defect that results in an vivo loss of calcium-dependent potassium efflux channel activity. This is corrected fully by the microinjection wild-type calmodulin into A cells and partially restored calmodulins from other organisms, but it cannot be calmodulin. Overall, these suggested unique features allow to restore normal phenotype might altered molecule. Previous studies established amino acid sequence showed several differences calmodulins,...

The escape of motile organisms from high concentrations chemicals was studied in Escherichia coli. We have found all tested to be osmorepellents. It shown both a spatial assay and temporal that the known sensory receptors for chemotaxis are not used osmotaxis, so different mechanism appears employed. According assay, between flagella is also tumbling response (at least solutions above 0.4 osmolar).

The isolated Ca2+ current from Paramecium caudatum was examined under voltage clamp with long conditioning depolarizations lasting for up to 5 min. transient inactivates tens of milliseconds due ‐dependent ‐channel inactivation (Brehm & Eckert, 1978). When this fast blocked by internally delivered EGTA, a much slower the discovered. This slow had time constants seconds, depending on voltage. development further following after 1 s interruptions depolarization. is dependent; rate higher...