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  • 1
    Electronic Resource
    Electronic Resource
    Introduction of impermeable molecules into pollen grains by electroporation (1995)
    Springer
    Protoplasma 187 (1995), S. 132-137 
    Details
    ISSN: 1615-6102
    Keywords: Electroporation ; Electropermeabilization ; Lilium longiflorum ; Pollen grains
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Electroporation was used to introduce plasma membrane impermeable molecules into the cytoplasm of pollen grains ofLilium longiflorum. Ungerminated pollen grains were exposed to the fluorescent dye quin2 or FITC-labelled dextrans and electroporated with exponentially decaying voltage pulses of 250 to 2000 V/cm and time constants of 0.01 to 10 μs. The number of electroporated pollen grains increased with the strength and duration of the voltage pulses, and with the osmolarity of the external medium. Optimal results were obtained with pulses of 1000 V/cm and 10 μs time constant, and with 900 mM mannitol in the electroporation buffer. The size of the pores produced in the plasma membrane by electroporation allowed uptake of 40 kDa dextran but not 70 kDa dextran. The rate of germination of pollen grains was low immediately after electroporation, but increased with time in pollen growth medium. The conditions of electroporation reported here may be used to load genetic material into pollen grains for the production of transgenic plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01280241
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Localization and release of allergens from tapetum and pollen grains ofBetula pendula (1999)
    Springer
    Protoplasma 208 (1999), S. 37-46 
    Details
    ISSN: 1615-6102
    Keywords: Allergens ; Allergy ; Betula pendula ; Immunolabelling ; Pollen grains ; Tapetum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Although intact pollen grains are assumed to be the primary carrier of pollen allergens, specific immunoreactive components have been found in other aerosol fractions, e.g., starch grains and remains of tapetal cells Cryo-scanning-electron-microscopy results demonstrate the presence of a clear network of strands connecting the tapetum with the microspores. The distribution of protein in tapetal orbicules, pollen wall, and pollen cytoplasm was tested by histochemical stains for light microscopy and transmission electron microscopy. The protein is mainly localized at the apertures and starch grains in the cytoplasm of pollen and in the core and on the surface of tapetal orbicules. Monoclonal antibodies Bv-10, BIP3, and BIP4 have been used to locate the cellular sites of pollen and tapetal allergens inBetula pendula (syn.B. verrucosa). The application of rapid-freeze fixation prevented relocation of allergens from their native sites. The allergens are predominantly found in the starch grains and to lesser extent in the exine. We also tested interactions between mature birch pollen and human fluids: saliva, nostrils fluid, and eyes solution. The aim was to mimic more closely the in vivo situation during allergenic response. In all cases we observed several pollen grains that were burst and had released their cytoplasmic contents. In the nose the allergens are released from the pollen within minutes. In rhinitis, nasal pH is increased from the normal pH 6.0 to 8.0. When we used nasal fluid at pH 8.0, the number of ruptured pollen grains increased. The mechanism that might induce formation of small allergen-bearing particles from living plant cells is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279073
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  • 3
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    Glutamate receptor-like genes form Ca2+ channels in pollen tubes and are regulated by pistil D-serine (2011)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2011-03-19
    Description: Elevations in cytosolic free calcium concentration ([Ca(2+)](cyt)) constitute a fundamental signal transduction mechanism in eukaryotic cells, but the molecular identity of Ca(2+) channels initiating this signal in plants is still under debate. Here, we show by pharmacology and loss-of-function mutants that in tobacco and Arabidopsis, glutamate receptor-like channels (GLRs) facilitate Ca(2+) influx across the plasma membrane, modulate apical [Ca(2+)](cyt) gradient, and consequently affect pollen tube growth and morphogenesis. Additionally, wild-type pollen tubes grown in pistils of knock-out mutants for serine-racemase (SR1) displayed growth defects consistent with a decrease in GLR activity. Our findings reveal a novel plant signaling mechanism between male gametophyte and pistil tissue similar to amino acid-mediated communication commonly observed in animal nervous systems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Michard, Erwan -- Lima, Pedro T -- Borges, Filipe -- Silva, Ana Catarina -- Portes, Maria Teresa -- Carvalho, Joao E -- Gilliham, Matthew -- Liu, Lai-Hua -- Obermeyer, Gerhard -- Feijo, Jose A -- New York, N.Y. -- Science. 2011 Apr 22;332(6028):434-7. doi: 10.1126/science.1201101. Epub 2011 Mar 17.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Instituto Gulbenkian de Ciencia, Rua da Quinta Grande, 6, P-2780-156 Oeiras, Portugal.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21415319" target="_blank"〉PubMed〈/a〉
    Keywords: 6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology ; Arabidopsis/genetics/metabolism ; Calcium/*metabolism ; Calcium Channels/genetics/*metabolism ; Calcium Signaling ; Cell Membrane/metabolism ; Cytosol/metabolism ; Excitatory Amino Acid Agonists/pharmacology ; Excitatory Amino Acid Antagonists/pharmacology ; Flowers/genetics/*metabolism ; Gene Expression Regulation, Plant ; Genes, Plant/*genetics ; Glycine/pharmacology ; Morphogenesis/drug effects ; Patch-Clamp Techniques ; Plants, Genetically Modified ; Pollen Tube/drug effects/growth & development/*metabolism ; Racemases and Epimerases/genetics/metabolism ; Receptors, Glutamate/*genetics/metabolism ; Serine/*metabolism/pharmacology ; Tobacco/genetics/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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