Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0277787 (stigma)
 13,352 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The spadix of skunk cabbage, Symplocarpus foetidus, is thermogenic and maintains an internal temperature of around 20 degrees C even when the ambient air temperature drops below freezing. This homeothermic heat production is observed only during the stigma stage, and thereafter ceases at the male stage when pollen is shed. To clarify the regulatory mechanism by which the stigma stage-specific heat production occurs in the spadix, sugars, organic acids, and amino acids in xylem sap were analyzed and compared with those of post-thermogenic plants. Interestingly, no significant difference was observed in the total volume of xylem sap per fresh weight of the spadix between thermogenic (31.2+/-24.7 microl h(-1) g(-1)) and post-thermogenic (50.5+/-30.4 microl h(-1) g(-1)) plants. However, concentrations of sugars (sucrose, glucose, and fructose), organic acids (malate and succinate), and amino acids (Asp, Asn, Glu, Gln, Gly, and Ala) in xylem sap decreased remarkably in post-thermogenic plants. Our results indicate that the composition of the xylem sap differs during the development of the spadix of S. foetidus.
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PMID:Changes in the composition of xylem sap during development of the spadix of skunk cabbage (Symplocarpus foetidus). 1597 47

Lily pollen tubes grow adhering to an extracellular matrix produced by the transmitting tract epidermis in a hollow style. SCA, a small ( approximately 9.4 kDa), basic protein plus low esterified pectin from this extracellular matrix are involved in the pollen tube adhesion event. The mode of action for this adhesion event is unknown. We partially separated three SCA isoforms from the lily stigma in serial size exclusion column fractions (SCA1, 9370 Da; SCA2, 9384 Da; SCA3, 9484 Da). Peptide sequencing analysis allowed us to determine two amino acid variations in SCA3, compared with SCA1. For SCA2, however, there are more sequence variations yet to be identified. Our structural homology and molecular dynamics modeling results show that SCA isoforms have the plant nonspecific lipid transfer protein-like structure: a globular shape of the orthogonal 4-helix bundle architecture, four disulfide bonds, an internal hydrophobic and solvent-inaccessible cavity, and a long C-terminal tail. The Ala(71) in SCA3, replacing the Gly(71) in SCA1, has no predictable effect on structure. The Arg(26) in SCA3, replacing the Gly(26) in SCA1, is predicted to cause structural changes that result in a significantly reduced volume for the internal hydrophobic cavity in SCA3. The volume of the internal cavity fluctuates slightly during the molecular dynamics simulation, but overall, SCA1 displays a larger cavity than SCA3. SCA1 displays higher activity than SCA3 in the in vitro pollen tube adhesion assay. No differences were found between the two SCAs in a binding assay with pectin. The larger size of the hydrophobic cavity in SCA1 correlates with its higher adhesion activity.
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PMID:Two SCA (stigma/style cysteine-rich adhesin) isoforms show structural differences that correlate with their levels of in vitro pollen tube adhesion activity. 1787 66

A number of Cucurbita pepo genotypes showing instable monoecy or partial andromonoecy, i.e. an incomplete conversion of female into bisexual flowers, have been detected. Given that in melon and cucumber andromonoecy is the result of reduction of ethylene production in female floral buds, caused by mutations in the ethylene biosynthesis genes CmACS7 and CsACS2; we have cloned and characterized two related C. pepo genes, CpACS27A and CpACS27B. The molecular structure of CpACS27A and its specific expression in the carpels of female flowers during earlier stages of flower development suggests that this gene is the Cucurbita ortholog of CmACS7 and CsACS2. CpACS27B is likely to be a paralogous pseudogene since it has not been found to be expressed in any of the analyzed tissues. CpACS27A was sequenced in Bolognese (Bog) and Vegetable Spaghetti (Veg), two monoecious inbred lines whose F2 was segregating for partial andromonoecy. The Bog allele of CpACS27A carried a missense mutation that resulted in a substitution of the conserved serine residue in position 176 by an alanine. Segregation analysis indicated that this mutant variant is necessary but not sufficient to confer the andromonoecious phenotype in squash. In concordance with its involvement in stamen arrest, a reduction in CpACS27A expression has been found in bisexual flower buds at earlier stages of development. This reduction in CpACS27A expression was concomitant with a downregulation of other ethylene biosynthesis and signaling genes during earlier and later stages of ovary development. The role of CpACS27A is discussed regarding the regulation of ethylene biosynthesis and signaling genes in the control of andromonoecy-associated traits, such as the delayed maturation of corolla and stigma as well as the parthenocarpic development of the fruit.
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PMID:Molecular and functional characterization of CpACS27A gene reveals its involvement in monoecy instability and other associated traits in squash (Cucurbita pepo L.). 2459 16