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 binding of soluble components of pollen grains to plant-stigma receptors can be inhibited by concanavalin A. This lectin-like activity of pollen components is important in the genetic control of plant reproduction. Aqueous extracts of allergenic pollens also react with concanavalin A. Agarose gel-diffusion precipitates were used to survey and characterize the ability of allergenic pollen extracts to react with concanavalin A and other lectins. Concanavalin A alone precipitated with extracts of plantain, American beech, white ash, and corn pollens. Surprisingly, extracts of the pollen from certain plants also precipitated when the extracts were diffused against pollen extracts from other plants. Pollen extracts of alfalfa, white ash, American beech, burweed marsh elder, redtop grass, corn, plantain, orchard grass, and aspen reacted with one or more other pollen extracts. Extract precipitin activity was reliably obtained after extracting pollens for 20 min with pH 7.5, 0.05M Tris buffer in 0.2M of saline. Optimal agarose gel conditions for detecting the precipitin reactions were pH 8.5 to 9.0, 75 mM borate buffer made to an ionic strength of 1.5M with NaCl for concanavalin A pollen reactions and 0.015M with NaCl for pollen-pollen reactions. The presence of the borate ion was necessary for optimal detection of the agarose gel precipitates. Studies of the inhibition of the lectin-pollen and pollen-pollen reactions with specific mono and disaccharides revealed many similarities and differences between the two types of reactions. The high concentrations of glycerol used to stabilize pollen extracts also inhibit these reactions.
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PMID:The lectin reactivity and lectin-like activity of allergenic pollen extracts. 642 89

Brassica self-incompatibility, a highly discriminating outbreeding mechanism, has become a paradigm for the study of plant cell-cell communications. When self-pollen lands on a stigma, the male ligand S cysteine-rich (SCR), which is present in the pollen coat, is transmitted to the female receptor, S-locus receptor kinase (SRK). SRK is a membrane-spanning serine/threonine receptor kinase present in the stigmatic papillar cell membrane. Haplotype-specific binding of SCR to SRK brings about pollen rejection. The extracellular receptor domain of SRK (eSRK) is responsible for binding SCR. Based on sequence homology, eSRK can be divided into three subdomains: B lectin-like, hypervariable, and PAN. Biochemical analysis of these subdomains showed that the hypervariable subdomain is responsible for most of the SCR binding capacity of eSRK, whereas the B lectin-like and PAN domains have little, if any, affinity for SCR. Fine mapping of the SCR binding region of SRK using a peptide array revealed a region of the hypervariable subdomain that plays a key role in binding the SCR molecule. We show that residues within the hypervariable subdomain define SRK binding and are likely to be involved in defining haplotype specificity.
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PMID:S cysteine-rich (SCR) binding domain analysis of the Brassica self-incompatibility S-locus receptor kinase. 1768 75

In Primula obconica, a species with a heteromorphic self-incompatibility system, the distinction between compatible and incompatible pollen tubes takes place on the stigma surface in thrum flowers, self tubes growing randomly over the papillar cells. No differences were seen between self and cross tube behaviour on the pin stigma surface, but self tubes were inhibited within the stigmatic tissue with differences in tube length evident after 24 h. The stigma surface bears a proteinaceous pellicle and binds the lectin Concanavalin A. Removal of the stigma removes the incompatibility barrier in mature gynoecia. Bud pollination shows that pollen tubes cannot grow in a normal manner on immature stigmas; the random growth of tubes over the stigma surface resembles that of mature thrum selfs. Fewer compatible tubes reach the style base of young gynoecia and smaller numbers of seeds are set than in mature flowers. Pin and thrum pollen grains germinate and grow in aqueous media, thrum tubes growing longer than pin. The presence of H3BO4 and CaCl2 in the growth medium promotes tube elongation and lengths equivalent to compatible styles can be obtained. The pollen grains have proteinaceous materials in their walls which diffuse out on moistening. Prolonged washing in aqueous media removes these materials but the incompatibility reaction remains unchanged. Thus the incompatibility reaction is between pollen tubes and stigmatic tissue and differs from the homomorphic, sporophytic system where pollen wall proteins elicit the incompatibility response.
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PMID:Studies on heteromorphic self-incompatibility systems: Physiological aspects of the incompatibility system of Primula obconica. 2427 Apr 36

Leprosy is a chronic inflammatory disease caused by Mycobacterium leprae that mainly affects the skin and peripheral nervous system, leading to a high disability rate and social stigma. Previous studies have shown a contribution of genes encoding products of the lectin pathway of complement in the modulation of the susceptibility to leprosy; however, the ficolin-3/FCN3 gene impact on leprosy is currently unknown. The aim of the present study was to investigate if FCN3 polymorphisms (rs532781899: g.1637delC, rs28362807: g.3524_3532insTATTTGGCC and rs4494157: g.4473C>A) and ficolin-3 serum levels play a role in the susceptibility to leprosy. We genotyped up to 190 leprosy patients (being 114 (60%) lepromatous), and up to 245 controls with sequence-specific PCR. We also measured protein levels using ELISA in 61 leprosy and 73 controls. FCN3 polymorphisms were not associated with disease, but ficolin-3 levels were higher in patients with FCN3 *2B1 (CinsA) haplotype (p = 0.032). Median concentration of ficolin-3 was higher in leprosy per se (26034 ng/mL, p = 0.005) and lepromatous patients (28295 ng/mL, p = 0.016) than controls (18231 ng/mL). In addition, high ficolin-3 levels (>33362 ng/mL) were more common in leprosy per se (34.4%) and in lepromatous patients (35.5%) than controls (19.2%; p = 0.045 and p = 0.047, respectively). Our results lead us to suggest that polymorphisms in the FCN3 gene cooperate to increase ficolin-3 concentration and that it might contribute to leprosy susceptibility by favoring M. leprae infection.
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PMID:Association of a new FCN3 haplotype with high ficolin-3 levels in leprosy. 2824 Oct 35