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Results for “PLETHORA”

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At least 37 records · Page 2Linked to original sources
PubMed1999

A plethora of presynaptic proteins associated with ATP-storing organelles in cultured astrocytes.

Cultured astrocytes can release a variety of messenger substances via receptor-mediated mechanisms, implicating their potential for regulated exocytosis and the participation of proteins of the SNARE complex. Here we demonstrate the astrocytic expression and organellar association of a large variety of synaptic proteins (synaptobrevin II, synaptotagmin I, synaptophysin, rab3a, synapsin I, SNAP-25, and syntaxin I) and also of the ubiquitous cellubrevin. As revealed by immunoblotting the expression of synaptic proteins was highest within the first few days after plating. Synaptophysin and SNAP-25 showed the most significant decline with prolonged culture time. Rab3a and synaptobrevin II were retained at a high level and synaptotagmin I, synapsin I, and syntaxin I at a lower level until 20 DIV. The immunoreaction for cellubrevin was low at the beginning and increased with prolonged culture time. As revealed by light microscopical immunocytochemistry the proteins are expressed by GFAP-positive astrocytes and associated with organelles of varying size. Immunoelectron microscopical analysis allocates synaptobrevin II and synaptophysin to the membranes of vesicular organelles. Double labeling experiments for pairs of synaptic proteins reveal that individual synaptic proteins can be entirely colocalized or partly reside on different organelles. Subcellular fractionation of astrocyte cultures by sucrose density gradient centrifugation after 2, 6, 13, and 20 DIV showed that the proteins sediment with ATP containing organelles of a broad density range. Our data suggest that messenger substances may be released from cultured astrocytes via receptor-mediated, Ca2+-dependent exocytosis.

Adenosine Triphosphate↗
PubMed1996

The transcriptional regulation of heat shock genes: a plethora of heat shock factors and regulatory conditions.

The inducible regulation of heat shock gene transcription is mediated by a family of heat shock factors (HSF) that respond to diverse forms of physiological and environmental stress including elevated temperature, amino acid analogs, heavy metals, oxidative stress, anti-inflammatory drugs, arachidonic acid, and a number of pathophysiological disease states. The vertebrate genome encodes a family of HSFs which are expressed ubiquitously, yet the DNA binding properties of each factor are negatively regulated and activated in response to specific conditions. This chapter will discuss the regulation of the HSF multi-gene family and the role of these transcriptional activators in the inducible expression of genes encoding heat shock proteins and molecular chaperones.

DNA-Binding Proteins↗
PubMed1993

Tapping an Amazônian plethora: four medicinal plants of Marajó Island, Pará (Brazil).

This study focused its attention on four medicinal plants (Carapa guianensis, Elephantopus scaber, Piper umbellatum, Stachytarpheta cayenensis) used by Caboclo communities on Marajó, the main island of the Amazon delta. In the field, interviews were conducted with Caboclos and the medicinal usages and preparation procedures of the four plants were recorded. In the laboratory, the plant extracts were subjected to bioassays and their crude chemical composition was established. All four plants showed significant bioactivity and the chemical tests confirmed the presence of bioactive compounds. In addition, the results of both the field and laboratory studies corresponded well with those of a literature search. The ethnopharmacological significance of the four plants is discussed.

Animals↗
PubMed1992

A plethora of intercellular signals during Caenorhabditis elegans development.

Reproducible cell-cell interactions contribute to the invariance of Caenorhabditis elegans development and allow high resolution study of molecular mechanisms of intercellular signaling. A number of new cell interactions have been discovered in the past year. The power of nematode molecular genetics has been increased through several technical advances and the genome project, and these new approaches are now being successfully applied both to familiar and new signaling mechanisms.

Animals↗
PubMed2005

A plethora of interacting organellar Ca2+ stores.

The endoplasmic reticulum is not the only major agonist-releasable Ca2+ store within cells; it is now clear that virtually all organelles so far studied have the ability to act as mobilizable Ca2+ stores. From recent findings with regard to Ca2+ transportation and Ca2+ homeostasis within a variety of cell organelles such as the mitochondria, nucleus, Golgi and lysosomes, it emerges that many of these organellar Ca2+ stores appear to interact with each other, adding a further level of complexity to Ca2+ signalling events.

Animals↗
PubMed2004

The PLETHORA genes mediate patterning of the Arabidopsis root stem cell niche.

A small organizing center, the quiescent center (QC), maintains stem cells in the Arabidopsis root and defines the stem cell niche. The phytohormone auxin influences the position of this niche by an unknown mechanism. Here, we identify the PLETHORA1 (PLT1) and PLT2 genes encoding AP2 class putative transcription factors, which are essential for QC specification and stem cell activity. The PLT genes are transcribed in response to auxin accumulation and are dependent on auxin response transcription factors. Distal PLT transcript accumulation creates an overlap with the radial expression domains of SHORT-ROOT and SCARECROW, providing positional information for the stem cell niche. Furthermore, the PLT genes are activated in the basal embryo region that gives rise to hypocotyl, root, and root stem cells and, when ectopically expressed, transform apical regions to these identities. Thus, the PLT genes are key effectors for establishment of the stem cell niche during embryonic pattern formation.

Arabidopsis↗
PubMed2004

A plethora of painful molecules.

Pain is a fundamental experience with a complex and multi-layered neurobiological basis. In recent years a powerful battery of techniques has been brought to bear to unravel the mechanisms by which painful stimuli are transduced and processed. There have been several recent discoveries regarding the molecular transduction mechanisms in nociceptors and novel molecular and cellular mechanisms underlying the spinal processing of painful stimuli. The mechanisms by which sensory neurons initiate hyperalgesia and touch evoked pain (allodynia) have been addressed particularly successfully in recent studies. The rich variety of key molecular players that have emerged in physiological and pathophysiological pain states reflects the sophistication and uniqueness of this vitally important sense.

Action Potentials↗