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Microfluorometry of pectic materials in the dehiscence zone of almond (Prunus dulcis [Mill.] DA Webb) fruits 总被引:2,自引:0,他引:2
K G Weis V S Polito J M Labavitch 《The journal of histochemistry and cytochemistry》1988,36(8):1037-1041
We examined the middle lamella and the primary and secondary walls in almond pericarp dehiscence zone cells using a fluorescent cytochemical method which permitted specific, quantitative detection of pectic cell wall materials. Glycol methacrylate-embedded sections were stained with coriphosphine and pectin-specific fluorescent emissions at 630 nm were quantified using green excitation (546 nm). Examination of sectioned material extracted with purified pecto-lytic enzyme preparations was used to demonstrate the relative specificity of the staining reaction for pectic substances. 相似文献
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Summary Dynamics of F-actin organization during activation and germination ofPyrus communis (pear) pollen was examined using rhodaminephalloidin. Prior to activation, the rhodamine-phalloidin labelling pattern appeared as circular profiles in the peripheral cytoplasm of the vegetative cell and as coarse granules around the vegetative nucleus. In activated pollen, parallel arrays of cortical F-actin were aligned circumferentially, along the polar axis in non-apertural areas of the pollen grain, and at 45° to 90° to the polar axis beneath the apertures. Some pollen also showed fluorescent granules or fusiform bodies dispersed throughout the cytoplasm, but as the number of such pollen diminished with prolonged incubation, these are being considered as intermediate patterns. In later stages, the filaments became organized as interapertural bundles traversing the three apertures. However, prior to emergence of the pollen tube, labelling became confined to a single aperture. In germinated pollen grains, actin microfilaments are aligned more or less axially with respect to the axis of the developing pollen tube.The granular labelling pattern seen around the vegetative nucleus prior to pollen activation also became clearly filamentous with pollen activation; this filamentous pattern persisted until germination when it was replaced by cables that aligned longitudinally with respect to the emerging tube axis.The results demonstrate that the organization of actin undergoes considerable changes in the period preceding pollen germination and that microfilament polarization is achieved before pollen germination. 相似文献
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Vito S. Polito 《American journal of botany》1980,67(3):274-277
A microspectrophotometric analysis of the DNA content of cell populations in the shoot apical meristem of young and adult stages of the filicalean fern Ceratopteris thalictroides was conducted to determine if the previously reported uptake of labeled DNA precursors by the apical cell was a consequence of endomitotic DNA replication or of DNA synthesis preceeding mitosis. Results demonstrate that in both the young and adult plants the estimated DNA content of the apical cell nuclei parallels that of the other cells of the meristem. There was no evidence of an “apical zone” of endopolyploid cells. 相似文献
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The mosquito fern, Azolla filiculoides Lam., was grown in a growth chamber on a nitrogen-free culture solution at 24 C under the following photoperiod: 16 hr light/8 hr darkness. Shoot tips were fixed every 2 hr for 24 hr to determine the mitotic index for the apical cell, immediate derivatives, and remaining cells to the level of the first leaf or lateral shoot primordium. Mitotic indices were 6.9%, 6.5% and 6.3%, respectively. The colchicine method was employed to determine the cell-cycle durations and duration of mitosis for the same populations of cells. The cell-cycle duration and duration of mitosis of the apical cell were 28.2 hr and 2.8 hr, respectively; for the immediate derivatives, 26.7 hr and 2.5 hr; for the remaining cells, 23.6 hr and 2.1 hr. Conclusions: the apical cell is as mitotically active as its immediate derivatives, and there is no evidence of a quiescent apical cell. 相似文献
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Alex D. Rogers Adam D. Leaché Kate L. Ciborowski Michael J. Polito Heather J. Lynch Michael J. Dunn Tom Hart 《Ecology and evolution》2016,6(6):1834-1853
Climate change, fisheries' pressure on penguin prey, and direct human disturbance of wildlife have all been implicated in causing large shifts in the abundance and distribution of penguins in the Southern Ocean. Without mark‐recapture studies, understanding how colonies form and, by extension, how ranges shift is challenging. Genetic studies, particularly focused on newly established colonies, provide a snapshot of colonization and can reveal the extent to which shifts in abundance and occupancy result from changes in demographic rates (e.g., reproduction and survival) or migration among suitable patches of habitat. Here, we describe the population structure of a colonial seabird breeding across a large latitudinal range in the Southern Ocean. Using multilocus microsatellite genotype data from 510 Gentoo penguin (Pygoscelis papua) individuals from 14 colonies along the Scotia Arc and Antarctic Peninsula, together with mitochondrial DNA data, we find strong genetic differentiation between colonies north and south of the Polar Front, that coincides geographically with the taxonomic boundary separating the subspecies P. p. papua and P. p. ellsworthii. Using a discrete Bayesian phylogeographic approach, we show that southern Gentoos expanded from a possible glacial refuge in the center of their current range, colonizing regions to the north and south through rare, long‐distance dispersal. Our findings show that this dispersal is important for new colony foundation and range expansion in a seabird species that ordinarily exhibits high levels of natal philopatry, though persistent oceanographic features serve as barriers to movement. 相似文献
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Stefania Raimondo Ornella Urzì Serena Meraviglia Marta Di Simone Anna Maria Corsale Nima Rabienezhad Ganji Antonio Palumbo Piccionello Giulia Polito Elena Lo Presti Francesco Dieli Alice Conigliaro Riccardo Alessandro 《Journal of cellular and molecular medicine》2022,26(15):4195
Chronic inflammation is associated with the occurrence of several diseases. However, the side effects of anti‐inflammatory drugs prompt the identification of new therapeutic strategies. Plant‐derived extracellular vesicles (PDEVs) are gaining increasing interest in the scientific community for their biological properties. We isolated PDEVs from the juice of Citrus limon L. (LEVs) and characterized their flavonoid, limonoid and lipid contents through reversed‐phase high‐performance liquid chromatography coupled to electrospray ionization quadrupole time‐of‐flight mass spectrometry (RP‐HPLC–ESI‐Q‐TOF‐MS). To investigate whether LEVs have a protective role on the inflammatory process, murine and primary human macrophages were pre‐treated with LEVs for 24 h and then were stimulated with lipopolysaccharide (LPS). We found that pre‐treatment with LEVs decreased gene and protein expression of pro‐inflammatory cytokines, such as IL‐6, IL1‐β and TNF‐α, and reduced the nuclear translocation and phosphorylation of NF‐κB in LPS‐stimulated murine macrophages. The inhibition of NF‐κB activation was associated with the reduction in ERK1‐2 phosphorylation. Furthermore, the ability of LEVs to decrease pro‐inflammatory cytokines and increase anti‐inflammatory molecules was confirmed ex vivo in human primary T lymphocytes. In conclusion, we demonstrated that LEVs exert anti‐inflammatory effects both in vitro and ex vivo by inhibiting the ERK1‐2/NF‐κB signalling pathway. 相似文献
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