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1.
Brain Topogr ; 29(4): 524-38, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26936595

RESUMEN

Relaxation and meditation techniques are generally characterized by focusing attention, which is associated with an increase of frontal EEG Theta. Some studies on music perception suggest an activation of Frontal Midline Theta during emotionally positive attribution, others display a lateralization of electrocortical processes in the attribution of music induced emotion of different valence. The present study examined the effects of vibroacoustic stimulation using a Body Monochord and the conventional relaxation music from an audio CD on the spontaneous EEG of patients suffering from psychosomatic disorders (N = 60). Each treatment took about 20 min and was presented to the patients in random order. Subjective experience was recorded via self-rating scale. EEG power spectra of the Theta, Alpha-1 and Alpha-2 bands were analysed and compard between the two treatment conditions. There was no lateralization of electrocortical activity in terms of the emotional experience of the musical pieces. A reduction in Alpha-2 power occurred during both treatments. An emotionally positive attribution of the experience of the vibroacoustically induced relaxation state is characterized by a more pronounced release of control. In the context of focused attention this is interpreted as flow experience. The spontaneous EEG showed an increase in Theta power, particularly in the frontal medial and central medial area, and a greater reduction in Alpha-2 power. The intensity of positive emotional feelings during the CD music showed no significant effect on the increase in Theta power.


Asunto(s)
Estimulación Acústica/métodos , Ritmo alfa , Emociones , Música/psicología , Trastornos Psicofisiológicos/psicología , Ritmo Teta , Adulto , Anciano , Electroencefalografía , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Vibración , Adulto Joven
2.
Ocul Immunol Inflamm ; 9(2): 75-84, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11449323

RESUMEN

PURPOSE: Gyrate atrophy (GA) is a rare hereditary disease that causes retinal destruction. Retinal damage in GA and other heredodegenerative diseases such as retinitis pigmentosa (RP) releases sequestered antigens and may trigger immune response to these molecules. Here, we studied the immune response to retinal antigens in patients with GA and RP and compared it with that of patients with inactive posterior uveitis and normal volunteers. PATIENTS AND METHODS: Peripheral blood was collected from 24 patients with RP, 10 patients with GA, 10 patients with inactive posterior uveitis, and 16 normal volunteers. Cell-mediated immune responses to human S-antigen (HS-Ag), bovine S-antigen (BS-Ag), and interphotoreceptor retinoid-binding protein (IRBP) were investigated by lymphocyte proliferation assay. In addition, serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were studied by ELISA. Immunologic data were correlated with clinical and electrophysiological findings. RESULTS: Patients with GA or RP responded to HS-Ag and BS-Ag more vigorously than patients with uveitis or healthy controls, as shown by higher mean stimulation indices and larger proportions of responders. Unlike S-Ag, IRBP stimulated low lymphocyte responses in only a small proportion of RP patients. The mean sVCAM-1 levels were significantly higher in the sera from patients with GA than in that from normal controls. CONCLUSION: An elevated cellular immune response to S-Ag is common in patients with GA and RP. This elevated cellular immune response to S-Ag may exacerbate retinal destruction in patients with GA and RP.


Asunto(s)
Arrestina/inmunología , Proteínas del Ojo , Atrofia Girata/inmunología , Retina/inmunología , Retinitis Pigmentosa/inmunología , Proteínas de Unión al Retinol/inmunología , Uveítis Posterior/inmunología , Adolescente , Adulto , Anciano , Autoantígenos/inmunología , Niño , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunidad Celular , Molécula 1 de Adhesión Intercelular/sangre , Activación de Linfocitos/inmunología , Masculino , Persona de Mediana Edad , Molécula 1 de Adhesión Celular Vascular/sangre
3.
Genome ; 43(2): 377-81, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10791827

RESUMEN

A dominant powdery mildew resistance gene introduced from Triticum timopheevii in line 146-155-T of common wheat, Triticum aestivum, was located on chromosome 6B by monosomic analysis. Restriction fragment length polymorphism (RFLP) and microsatellite analyses detected the presence of a T. timopheevii segment, translocated to chromosome 6B, with breakpoints between the loci Xpsr8/Xpsr964 on 6BS and Xpsr154/Xpsr546 on 6BL. The novel powdery mildew resistance gene, which has been designated Pm27, was shown to cosegregate with the microsatellite locus Xpsp3131, which is located on the introgressed T. timopheevii segment. The molecular data confirm the location of Pm27 on the translocated 6B chromosome.


Asunto(s)
Triticum/genética , Alelos , Mapeo Cromosómico , Electroforesis en Gel de Poliacrilamida , Inmunidad Innata/genética , Repeticiones de Microsatélite , Modelos Genéticos , Enfermedades de las Plantas/genética , Polimorfismo de Longitud del Fragmento de Restricción
4.
Am J Pathol ; 156(4): 1425-32, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10751366

RESUMEN

Telomerase activation, being a cardinal requirement for immortalization, is a crucial step in the development of malignancy. With a view toward diagnostic and biological aspects in melanocytic neoplasia, we investigated the relative levels of telomerase activity in 72 nevi and 16 malignant melanomas by means of a modified telomeric repeat amplification protocol (TRAP) assay, including an internal amplification standard. We further compared telomerase activity with the expression of two different proliferation-specific proteins, Ki-67 and repp86, a protein expressed exclusively in the cell cycle phases S, G2, and M. Telomerase activity was associated with the overall growth fraction (Ki-67) but showed a closer correlation with the expression of repp86. Both telomerase activity and proliferation indices discriminated clearly between malignant melanomas and nevi, but not between common and dysplastic nevi. Nonetheless, a portion of nevi exhibited markedly elevated telomerase activity levels without proportionally increased proliferation. This was independent of discernible morphological changes. Clinicopathological correlations showed an association between high telomerase activity and early metastatic spread in melanomas, linking telomerase to tumor biology. Our results provide arguments in favor of an occasional progression from nevi to melanomas and imply that proliferation measurements in combination with telomerase assays may help to elicit early malignant transformation that is undetectable by conventional morphology.


Asunto(s)
Síndrome del Nevo Displásico/enzimología , Melanocitos/enzimología , Melanoma/enzimología , Telomerasa/metabolismo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor , Niño , Preescolar , Síndrome del Nevo Displásico/patología , Femenino , Humanos , Inmunohistoquímica , Lactante , Masculino , Melanoma/patología , Persona de Mediana Edad
5.
Cell Motil Cytoskeleton ; 43(2): 145-58, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10379839

RESUMEN

We investigated the nature of the locomotory waves of Koruga and Deltotrichonympha, flagellates living symbiotically in the hindgut of the Australian termite Mastotermes darwiniensis. The locomotory waves consist of two components: metachronal waves of flagellar beating and undulations of the cell surface, which propagate synchronously with the same wavelength, frequency, and velocity. We asked, do body waves cause flagellar waves, or vice versa? Using video microscopy and selective inhibitors and drugs, we found that (1) the amplitude of flagellar waves remains constant independent of variations in the amplitude of body waves, (2) flagellar waves can occur in the complete absence of body waves, (3) flagellar waves can induce body waves on swollen regions, (4) inhibition of flagellar beating by dynein inhibitors causes disappearance of body waves, and (5) cytochalasin D induces changes in cell shape but does not inhibit locomotory waves. Therefore, flagellar waves are not produced passively by an active contractile system in the cell cortex; instead, metachronally beating flagella exert waves of pressure that induce passive undulations of a pliant cell surface. These results support Machemer's [1974] theoretical analysis of the data of Cleveland and Cleveland [1966: Arch. Protistenk. 109:39-63], who believed the opposite.


Asunto(s)
Eucariontes/fisiología , Isópteros/parasitología , Animales , Eucariontes/ultraestructura
6.
Microsc Res Tech ; 44(4): 293-303, 1999 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-10098929

RESUMEN

Cell-cell adhesion in the various types of intercellular junctions of differentiated tissues is relatively stable and permanent. In migrating cells of embryos, or in wound closure, inflammatory responses and tumors of adult tissues, however, bonds between cells are made and broken and made again, i.e., cell-cell adhesions are transient and reversible. These nonjunctional contacts lack the organized structure of intercellular junctions, but may initiate their tissue-specific formation during development. Investigation of dynamic, nonjunctional cell-cell adhesions has been hampered by the asynchronous and heterogeneous distribution of these transient contacts among groups of moving cells. We recently discovered a novel system of reversible cell adhesion in a differentiated tissue that overcomes this difficulty. Here I review our current knowledge of this system, particularly its unique experimental advantages for investigating the mechanisms and control of dynamic cell adhesion.


Asunto(s)
Actinas/metabolismo , Adhesión Celular/fisiología , Cnidarios/fisiología , Citoesqueleto/química , Boca/fisiología , Animales , Microscopía Electrónica , Boca/ultraestructura
7.
Nucleic Acids Res ; 25(4): 919-21, 1997 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-9016650

RESUMEN

Human somatic cells have essentially no telomerase activity. Telomerase is linked to tumor genesis and is a valuable marker for malignant growth. Extreme paucity of the enzyme neccessitated development of a PCR-based assay, 'telomeric repeat amplification protocol' (TRAP). Unfortunately, this method is not without difficulties. Amplification products are not related to the size of the amplified telomerase products. Furthermore, false positive results can occur, and careful control of reaction conditions is crucial. We analyzed in detail the molecular basis of artifacts. Based on these data, reverse PCR primer was changed and both problems in the TRAP assay were eliminated.


Asunto(s)
Artefactos , Cartilla de ADN , Técnicas de Amplificación de Ácido Nucleico , Telomerasa/metabolismo , Secuencia de Bases , Reacciones Falso Positivas , Humanos , Datos de Secuencia Molecular
8.
J Neurocytol ; 24(9): 711-23, 1995 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-7500125

RESUMEN

We present ultrastructural evidence for the first known example of a giant nerve net in the phylum Ctenophora. The giant fibre system in Beroë underlies paired strips of adherent epithelial cells that run inside the lips. Interlocking actin-lined cell junctions between opposing adhesive strips keep Beroë's large mouth closed while the ctenophore searches for prey. The giant neurons, up to 6-8 microns in diameter, form a continuous lattice-like plexus rich in vesicles, microtubules, and 'presynaptic triads'. A novel feature is that individual giant axons make synaptic contacts with more than one type of effector, i.e. longitudinal muscle fibres and epithelial adhesive cells. Contact of prey with sensory receptors on the lips of Beroë induces rapid disappearance of the actin-lined adhesive cell junctions, and muscular opening of the mouth to ingest prey. Electron microscopy of food-opened mouths shows local thickening of longitudinal muscles and widening of the basal ends of epithelial cells in the adhesive strip, correlated with retraction of the adhesive epithelium into the mesoglea. Addition of 1% Triton X-100 to formaldehyde fixative in the absence of prey also elicits regional thickening of longitudinal muscles at the location of the adhesive strips (visualized by rhodamine-phalloidin staining). The giant neuron system may serve as a final common pathway to rapidly signal disassembly of actin-based junctions between adhesive cells as well as contractions of longitudinal muscles underlying the adhesive strips, thereby enabling Beroë to open its mouth rapidly to engulf prey.


Asunto(s)
Invertebrados/anatomía & histología , Red Nerviosa/ultraestructura , Sinapsis/ultraestructura , Animales , Adhesión Celular , Colorantes , Ingestión de Alimentos/fisiología , Epitelio/ultraestructura , Formaldehído , Microscopía Electrónica , Microscopía Fluorescente , Boca/inervación , Contracción Muscular , Neuronas/ultraestructura , Octoxinol , Faloidina , Rodaminas
9.
J Fr Ophtalmol ; 18(6-7): 481-3, 1995.
Artículo en Francés | MEDLINE | ID: mdl-7560791

RESUMEN

In the ocular area, myxoma is a benign and uncommon tumor located essentially in the lids, more rarely in the conjunctiva. We report the case of a 31-year-old male suffering from the recent growth of an epibulbar painless tumefaction located in the temporal conjunctiva. This gelatinous mass was excised and has revealed a conjunctival myxoma. Surgical excision and histopathologic examination of such epibulabar lesions are necessary because they are few malignant tumors, like botryoid rhabdomyosarcoma or fibrosarcoma, which may have a similar clinical aspect.


Asunto(s)
Neoplasias de la Conjuntiva/patología , Mixoma/patología , Adulto , Neoplasias de la Conjuntiva/cirugía , Humanos , Masculino , Mixoma/cirugía
10.
Trends Cell Biol ; 4(9): 305-10, 1994 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-14731466

RESUMEN

Ca(2+) plays a key role in the regulation of ciliary and flagellar movement. This article focuses on the initial steps of this regulation: how and where Ca(2+) enters cilia and flagella to trigger specific changes in axonemal motility. This knowledge is fundamental for understanding the sites, molecular targets and mechanisms of action of Ca(2+) within the cilium of flagellum.

11.
J Cell Biol ; 125(5): 1127-35, 1994 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8195294

RESUMEN

To image changes in intraciliary Ca controlling ciliary motility, we microinjected Ca Green dextran, a visible wavelength fluorescent Ca indicator, into eggs or two cell stages of the ctenophore Mnemiopsis leidyi. The embryos developed normally into free-swimming, approximately 0.5 mm cydippid larvae with cells and ciliary comb plates (approximately 100 microns long) loaded with the dye. Comb plates of larvae, like those of adult ctenophores, undergo spontaneous or electrically stimulated reversal of beat direction, triggered by Ca influx through voltage-sensitive Ca channels. Comb plates of larvae loaded with Ca Green dextran emit spontaneous or electrically stimulated fluorescent flashes along the entire length of their cilia, correlated with ciliary reversal. Fluorescence intensity peaks rapidly (34-50 ms), then slowly falls to resting level in approximately 1 s. Electrically stimulated Ca Green emissions often increase in steps to a maximum value near the end of the stimulus pulse train, and slowly decline in 1-2 s. In both spontaneous and electrically stimulated flashes, measurements at multiple sites along a single comb plate show that Ca Green fluorescence rises within 17 ms (1 video field) and to a similar relative extent above resting level from base to tip of the cilia. The decline of fluorescence intensity also begins simultaneously and proceeds at similar rates along the ciliary length. Ca-free sea water reversibly abolishes spontaneous and electrically stimulated Ca Green ciliary emissions as well as reversed beating. Calculations of Ca diffusion from the ciliary base show that Ca must enter the comb plate along the entire length of the ciliary membranes. The voltage-dependent Ca channels mediating changes in beat direction are therefore distributed over the length of the comb plate cilia. The observed rapid and virtually instantaneous Ca signal throughout the intraciliary space may be necessary for reprogramming the pattern of dynein activity responsible for reorientation of the ciliary beat cycle.


Asunto(s)
Calcio/fisiología , Cilios/fisiología , Animales , Estimulación Eléctrica , Colorantes Fluorescentes , Invertebrados , Larva , Movimiento
12.
Klin Monbl Augenheilkd ; 203(3): 230-1, 1993 Sep.
Artículo en Alemán | MEDLINE | ID: mdl-8264216

RESUMEN

A 49-year-old patient with relapsing polychondritis, who presented in the first instance to an eye department, is described. The patient had episcleritis, papilloedema and posterior scleritis. Both auricles were red, swollen and tender under pressure. The patient responded well to systemic steroid therapy for two weeks. Relapsing polychondritis is a rare connective tissue disorder. Early diagnosis is important, as progressive disease may cause lesions of vital organs (lung, heart).


Asunto(s)
Enfermedades de los Cartílagos/diagnóstico , Enfermedades del Tejido Conjuntivo/diagnóstico , Enfermedades del Oído/diagnóstico , Oído Externo , Hiperemia/diagnóstico , Escleritis/diagnóstico , Diagnóstico Diferencial , Oído Externo/irrigación sanguínea , Angiografía con Fluoresceína , Humanos , Masculino , Persona de Mediana Edad , Papiledema/diagnóstico
13.
J Cell Sci ; 106 ( Pt 1): 355-64, 1993 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-7903672

RESUMEN

We used rhodamine-phalloidin and ultrastructural methods to follow dynamic changes in adhesive cell junctions and associated actin filaments during reversible epithelial adhesion in the mouth of the ctenophore Beroë. A cruising Beroë keeps its mouth closed by interdigitated actin-coated appositions between paired strips of cells lining the lips. The mouth opens rapidly (in 0.2-0.3 s) by muscular action to engulf prey (other ctenophores), then re-seals after ingestion. We found that the interlocking surface architecture of the adhesive cells, including the actin-coated junctions, rapidly disappears after food-induced opening of the mouth. In contrast, forcible separation of the lips in the absence of food rips the junctions, still intact, from the surfaces of the cells. The prey-stimulated loss of adhesive cell junctions and associated actin cytoskeleton is one of the most rapid changes in actin-based junctions yet observed. This system provides unique experimental advantages for investigating the dynamic control of reversible cell adhesions and membrane-associated actin filaments.


Asunto(s)
Actinas/metabolismo , Cnidarios/fisiología , Ingestión de Alimentos/fisiología , Uniones Intercelulares/ultraestructura , Animales , Adhesión Celular , Cnidarios/ultraestructura , Citoesqueleto/ultraestructura , Células Epiteliales , Estrés Mecánico
14.
J Cell Sci ; 104 ( Pt 4): 1251-62, 1993 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8391017

RESUMEN

Cilia with a distal membrane expansion enclosing a coiled end of the axoneme (paddle cilia or discocilia) have been commonly reported in marine invertebrates. We recently showed that paddle cilia in molluscan veligers are artifacts of non-physiological conditions. Here we investigated the possible mechanisms of formation of paddle cilia under hypotonic conditions; particularly, whether a helical conformational change of doublet microtubules induced by Ca or proton flux is responsible. Typical paddle cilia are induced by hypotonic Ca-free solutions at normal or low pH, showing that axonemal coiling does not require Ca influx or proton efflux. In addition, Triton-demembranated straight axonemes do not coil in high Ca solutions. Most decisively, complete removal of paddle ciliary membranes with detergents, but not mere permeabilization, causes immediate uncoiling and straightening of the axonemes to approximately their original length before hypotonic treatment. These findings and other data show that axonemal coiling in paddles is due to membrane tensile stress acting on an elastic axoneme. Light and electron microscopy of paddles show that axonemes coil uniformly toward the direction of the effective stroke (doublets nos 5-6), even when beating is inhibited by sodium azide or glutaraldehyde before hypotonic treatment. This indicates that axonemes possess an intrinsic asymmetry of stiffness within the beat plane, independent of active microtubule sliding. Paddle cilia thus reveal important mechanical properties of ciliary axonemes and membranes that should be useful for understanding ciliary function.


Asunto(s)
Cilios/ultraestructura , Membranas Intracelulares/fisiología , Animales , Fenómenos Biomecánicos , Calcio/farmacología , Elasticidad , Soluciones Hipotónicas , Microscopía Electrónica , Moluscos , Presión Osmótica , Protones , Estroncio/farmacología
15.
Philos Trans R Soc Lond B Biol Sci ; 339(1287): 1-16, 1993 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-8096084

RESUMEN

The electromotor behaviour of ciliary comb plates was studied during prey-stimulated and electrically stimulated feeding by intact Pleurobrachia pileus (Müller). Comb plate electrical activity was recorded by extracellular electrodes attached directly to the cilia; comb plate motility was recorded by high-speed video microscopy. Comb plate electrical activity fell into two distinct classes, identified by waveform and amplitude: (i) excitatory postsynaptic potentials (EPSPS) in the comb plate (polster) cells and (ii) regenerative potentials in the cilia, as described previously (Moss & Tamm 1987). Slow phasic bursts of regenerative potentials (reversal volleys) were observed in comb plates of rows undergoing reversed beating during capture of prey or by rhythmic electrical stimulation of the tentacles. All plates of a given comb row exhibited virtually identical electrical activity. Timing and development of electrical activity in comb plates of the subtentacular (ST) rows were nearly identical even though separated by several centimetres; onset of the reversal volleys of plates of subsagittal (ss) rows were delayed on average by about 0.5 s relative to the ST rows, although individual EPSPS displayed very similar timing. Microsurgery, combined with extracellular recording from comb plates and the tentacle and associated basal structures, revealed the presence of an integrative center in the tentacular bulb. This communicates with the comb plates by means of a diffuse pathway, presumably the nerve net, which itself is maximally sensitive to rhythmic input. The pathway underlying the reversal volley may innervate only the stimulated hemisphere. In addition to the rhythmic pathway, a through-conducting pathway runs from distal regions of the tentacle to the comb plate cells. Yet another excitatory pathway, possibly distinct from the tentacular through-conducting pathway, may mediate certain cases of global postsynaptic activity. The pathway that controls mouth movements during feeding is entirely independent of any comb plate pathway.


Asunto(s)
Invertebrados/fisiología , Animales , Cilios/fisiología , Estimulación Eléctrica , Electrofisiología , Conducta Alimentaria/fisiología , Invertebrados/anatomía & histología , Movimiento/fisiología , Fenómenos Fisiológicos del Sistema Nervioso
16.
Mech Ageing Dev ; 62(2): 209-21, 1992 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-1569790

RESUMEN

The age-related changes of the ciliary muscle of human eyes (33-87 years) were studied on histological meridional sections. Eighty-five melanoma eyes and 10 eyes of normal donors were investigated. The total area and the length of the muscle, the area of the three main portions and the distance of the inner apex of the muscle to the scleral spur were determined and correlated with age. Total area and length of the muscle show a continuous and significant decrease with age. The area of the longitudinal and reticular portion continuously decreases, whereas the area of the circular portion significantly increases with age. The decrease in area is more pronounced in the longitudinal portion than in the reticular portion of the muscle, which shows an age-related increase in connective tissue. In addition, the distance of the inner apex of the muscle to the scleral spur shortens continuously. Thus, with increasing age the ciliary muscle adopts an anterior-inward position. A similar form is seen in young eyes after ciliary muscle contraction only. There might be a functional relationship between the observed age-changes in the ciliary muscle system and the phenomenon of the so-called 'lens paradox' (steepening of the anterior and posterior curvatures of the disaccommodated lens with age).


Asunto(s)
Envejecimiento/patología , Músculos Oculomotores/anatomía & histología , Adulto , Anciano , Anciano de 80 o más Años , Tejido Conectivo/patología , Femenino , Humanos , Cristalino/patología , Masculino , Persona de Mediana Edad , Atrofia Muscular/patología , Músculos Oculomotores/patología , Presbiopía/etiología , Presbiopía/patología
17.
Biol Bull ; 182(3): 382-390, 1992 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29304584

RESUMEN

We investigated arrest and inactivation responses of stigmatal cilia in the branchial basket of the ascidian, Ciona intestinalis. Using an improved preparation of living tissue for microscopic imaging of ciliary responses, we found that Ca-ionophore A23187 in seawater + 50 mM Ca caused actively beating cilia to assume the upright inactive posture, while A23187 in seawater + 100 mM Ca caused transient (5-10 s) stigma-wide arrests in which the cilia lie flat against the stigmatal walls. Both responses are therefore Ca dependent, but the inactive state has a lower threshold for Ca than does arrest. Membrane permeant cAMP analogues induced >40% of the quiescent cilia within a stigma to begin beating. Saponin-extracted models of stigmatal cilia were developed to study the ionic and molecular control of ciliary activity in Ciona. Extracted cilia were stimulated to beat vigorously for >45 min by ATP-containing reactivation solution (RS). Addition of 10-5 to 10-3 M Ca to reactivation solution caused the cilia to stand upright (inactivate), but not to arrest. The calmodulin antagonists trifluoperazine and calmidazolium (100 µM) restored active beating when included in RS + 50-100 µM Ca, thereby reversing Ca-dependent inactivation. Addition of bovine brain calmodulin to RS + 100 µM Ca did not cause arrest of reactivated cilia. RS + 100 µM cAMP + 1 mM 3-isobutyl-1-methyl-xanthine or the catalytic subunit of cAMP-dependent protein kinase increased both the proportion and vigor of reactivated beating. Addition of 100 µM Ca to the RS + cAMP + IBMX solution caused reactivated cilia to vibrate or twitch in an upright position, suggesting that Ca and cAMP have antagonistic effects on stigmatal cilia.

18.
Mol Biol (Mosk) ; 25(3): 614-23, 1991.
Artículo en Ruso | MEDLINE | ID: mdl-1658617

RESUMEN

The plasmid-transposon Tn9-322 was constructed by inverted transposition from the pBR322::Tn9 plasmid. The precise excision of the Tn9-322 transposon from the proB gene site can proceed by the Campbell's model. This fact was demonstrated by appearance of the plasmid-transposons after their precise excision. They contain two IS1 elements flanking a short direct repeat of the target DNA. The recombinational mechanism of precise excision of Tn9 type transposons seems not to be alternative but looks as an additional one to a well-known slippage mechanism proved for Tn5 and Tn10.


Asunto(s)
Elementos Transponibles de ADN , Escherichia coli/genética , Secuencia de Bases , ADN Bacteriano/genética , Genes Bacterianos , Datos de Secuencia Molecular , Plásmidos
19.
Cell Tissue Res ; 264(1): 151-9, 1991 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1711417

RESUMEN

We have investigated the actin content and ultrastructure of two kinds of presumed sensory projections on the lip epidermis of beroid ctenophores. Transmission electron microscopy showed that conical pegs contain a large bundle of densely packed, parallel microfilaments. Rhodamine-phalloidin brightly stained the pegs, confirming that they contain filamentous actin. Epidermal cells with actin pegs also bear a single long cilium with an onion-root structure, previously described as arising from a different type of cell. The actin peg and onion-root cilium project side-by-side, defining a polarized axis of the cell which is shared by neighboring cells. The onion-root body is surrounded by a flattened membrane sac which lies immediately below the plasma membrane. The perimeter of the membrane sac is encircled by aggregates of dense material. An extra layer of dense material is found along the side of the membrane sac facing the peg; this material often makes direct contact with the adjacent actin filament bundle. Cells with actin pegs and onion-root cilia synapse onto adjacent neurites and secretory gland cells, indicating that one or both types of projections are sensory elements. Since the feeding responses of beroids are reported to depend on chemical and tactile stimuli to the lips, the cells bearing pegs and cilia may function as both mechanoreceptors and chemoreceptors, that is, as double sensory receptors.


Asunto(s)
Cnidarios/ultraestructura , Células Receptoras Sensoriales/ultraestructura , Actinas/metabolismo , Actinas/ultraestructura , Animales , Cnidarios/metabolismo , Microscopía Electrónica , Faloidina , Rodaminas , Células Receptoras Sensoriales/metabolismo , Coloración y Etiquetado
20.
Biol Bull ; 181(2): 355-356, 1991 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29304610
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