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In plants, the outer epidermal cell wall and cuticle presents a semipermeable barrier that maintains the external integrity of the plant and regulates the passage of various classes of molecules into and out of the organism. During vegetative development, the epidermal cells remain relatively inert, failing to respond to wounding or grafting. During(More)
Although the plant epidermis serves primarily a protective role, during plant development some epidermal cells specialize, becoming competent to interact not only with pollen but also with other epidermal cells. In the former case, these interactions mediate recognition, germination, and pollen growth responses and, in the latter case, result in interorgan(More)
During male meiosis in wild-type Arabidopsis the pollen mother cell (PMC) undergoes two meiotic nuclear divisions in the absence of cell division. Only after telophase II is a wall formed which partitions the PMC into four microspores. Each microspore undergoes two subsequent mitotic divisions to produce one vegetative cell and two sperm cells in the mature(More)
A full-length cDNA of the M1 double-stranded RNA killer preprotoxin coding region successfully directed the synthesis of secreted K1 toxin when expressed in Saccharomyces cerevisiae from a plasmid vector. Three protein species immunoreactive with antitoxin antiserum were detected intracellularly in transformants harboring this killer cDNA plasmid. These(More)
Two cDNA clones of the segment of Saccharomyces cerevisiae M1 double-stranded RNA, which codes for the yeast killer toxin, have been expressed in yeast using the expression vector pYT760. Toxin expression and secretion depended upon the presence of a yeast promoter. Transformants not only contain an authentic preprotoxin precursor, as determined by(More)
We have examined the effects of seven different “barrier breakers” (including ethanol, aspirin, salicylic acid, isobutyric acid, Na taurocholate, thermal injury, and hyperosmotic glucose) on chambered gastric mucosae of rats in an attempt to identify variations in accepted indicators of mucosal barrier integrity which would accurately predict the extent of(More)
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