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PubMed2026

Comparative transcriptomics reveals hormone signaling and MADS-box genes in divergent development of inflorescences and tendrils in grapevine lateral shoots.

Hormone signaling and MADS-box genes regulate grapevine tendril and inflorescence growth divergence, offering molecular insights for managing tendril growth. Grapevine (Vitis vinifera L.) tendrils and inflorescences are homologous organs; however, their divergent development has important agronomic consequences because excessive tendril growth increases vineyard management costs. To explore the regulatory mechanisms, we compared the inflorescence-prone cultivar 'Einset Seedless' (ENT) with the tendril-prone cultivar 'Pinot Noir' (PN) using anatomical observation, transcriptome analysis of specific tendril nodes, and functional characterization of MADS-box genes. ENT exhibited a higher flowering rate at tendril nodes 1-4 than PN. Transcriptome profiling of specific tendril nodes uncovered 549 differentially expressed genes (DEGs) through an intersection/exclusion strategy, with Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment indicating that hormone and mitogen-activated protein kinase (MAPK) signaling were the primary candidates driving the divergence. To assess the spatiotemporal dynamics of these DEGs, we performed Mfuzz clustering, which revealed that multiple expression trajectories were highly consistent with the flowering gradient across different ENT and PN nodes. Plant hormone signal transduction was the predominantly enriched pathway across all dynamic clusters, highlighting the centrality of phytohormones in this process. Guided by this transcriptional evidence, we measured endogenous zeatin and gibberellin (GA₃) contents in the nodal tissues. Remarkably, the zeatin-to-GA₃ ratio not only paralleled the flowering gradient but also correlated with the cluster expression trajectories, providing physiological evidence for a cytokinin-gibberellin interaction model governing organ divergence. Additionally, we analyzed the differentially expressed transcription factors among the DEGs and identified a MADS-box gene, FRUITFULL-LIKE (VvFUL-L), which was markedly upregulated in PN tendrils. Heterologous overexpression of VvFUL-L in arabidopsis promoted early flowering and reduced inflorescence branching, suggesting its potential role in regulating lateral meristem development and affecting tendril formation. Collectively, these findings establish that Hormone Signaling, particularly cytokinin-GA crosstalk, and MADS-box regulators, such as VvFUL-L, are key regulators of inflorescence versus tendril growth in grapevines, providing a basis for future molecular and breeding studies.

Vitis↗

PubMed2026

Pleiotropic mutation in a tendril TCP gene underlies the yield-enhancing multiple-flowering trait in summer squash (Cucurbita pepo).

Crop yield is a focal point in plant breeding. Regulation of lateral budding through apical dominance was a central target of crop domestication, directly affecting crop production. The young fruits of Cucurbita pepo, summer squash, are produced on plants characterized by apical dominance and differentiation of a single flower bud per leaf axil. A single recessive mutation, mf, results in differentiation of more than one flower per leaf axil, thereby directly increasing production because of the continual day-to-day harvest of the summer squash crop. Positional cloning of the Cucurbita pepo mf (Cpmf) gene denoted a frameshift mutation in a TCP transcription factor, Cp4.1LG13g07780, as causative for the increase in axillary flowering. Cpmf is an ortholog of a tendril-development TCP gene in other cucurbits, and likewise, the recessive allele of Cpmf is associated with distorted tendril development. Gene function is context dependent, and we propose that multiple flowering is a unique pleiotropic attribute of mutation in a tendril-development gene of C. pepo. Characterization of a C. pepo collection confirmed a significant association of the Cpmf mutation with multiple flowering and showed that the mutant allele is absent in ancestral C. pepo and one of its two cultivated subspecies. The beneficial mutation occurred and was selected after the domestication of the other subspecies, during its cultivation for young fruit production. We demonstrate the discovery of a causative yield-increasing sequence variant and its practical utilization in breeding. Our findings provide a molecular target for creation of high-yielding, multiple-flowering summer squash cultivars through marker-assisted breeding or precise genome editing.

Cucurbita↗

PubMed1979

Scanning electron-microscopic observations on the surfaces of chorionic villi of young and mature placentas.

Mature placental material of full-term spontaneous births and 4-, 6-, 8- and 10-week-old placentas obtained from curettage cases were fixed in glutaraldehyde and osmium tetroxide for SEM examination. In young placentas, the ramifications of the chorionic villi start in the form of buds. The buds are transformed into tendrils with swollen extremities. These swellings resemble buds ready to bloom. The villi intertwine in different positions; both the villi and their tendrils are covered with dense layers of microvilli. In mature placentas, the surfaces of the chorionic villi and their ramifications are covered with microvilli. However, in comparison with the microvilli of young placentas, the microvilli here are less numerous and shorter. Invaginations were clearly visible on the surfaces of the villi; younger and newly budding microvilli, similar to those observed in young placentas, were seen in the invaginated regions. We had the impression that the mature placentas must regenerate in order to meet the increasing physiological requirements of the fetus.

Chorionic Villi↗

PubMed1976

Some observations on the ultrastructure of developing rat cerebral capillaries.

Developing blood vessels in rat cerebral cortex were studied at a number of stages between 3 and 28 days postnatal, in an attempt to obtain data on the mechanisms by which the lumen is established within cords of mesodermal cells. A combination of techniques was utilized in an attempt to elucidate these mechanisms. These were: (a) aldehyde fixation and block staining with phosphotungstic acid; (b) aldehyde perfusion followed by perfusion of a lead solution and post-fixation in osmium tetroxide; (c) conventional preparation of tissue with aldehyde and osmium fixation. Support for interendothelial lumen formation was readily forthcoming, including vessels with junctions between two or more endothelial cells cut transversely. There was some support for intraendothelial lumen formation, in the form of "seamless" endothelial cells. Other features noted included the presence of free ribosomes and vacuoles in the endothelial cells, endothelial flaps, sprouts and tendrils, intraluminal debris, endothelial degeneration and a junction with a nonendothelial cell. Large numbers of endothelial vacuoles were noted, many of them occurring at the abluminal edge of the cells. These vacuoles may be involved in the formation of intraendothelial lumina and also in the enlargement of both types of lumina. This study provides evidence that besides the well-established interendothelial lumen formation, intraendothelial mechanisms may also be operative in rat cerebral cortex. The techniques employed in this study offer the potential for clarifying these and related issues.

Animals↗

PubMed1978

A spectroscopic and electron microscopic examination of the highly condensed DNA structures formed by denaturation in Mg(ClO4)2.

1. Thermal denaturation in 1.5 M Mg(ClO4)2 of the DNA from bacteriophage lambda results in four well-separated subtransitions, as monitored by the accompanying increase in absorbance. The midpoint of the hyperchromic spectrum is significantly lowered compared to either 1.5 M MgCl2 or 3.0 M NaClO4. 2. The first two subtransitions are associated with the melting of the A . T-richest regions of the lambda DNA, as revealed by electron micrographs following fixation with formaldehyde. 3. Commencing with the third subtransition, an unusual DNA structure is observed in electron micrographs. In this structure the A . T-rich half of the molecule appears completely condensed, whereas the G . C-rich half remains native. 4. During the fourth subtransition DNA molecules condense completely and eventually aggregate to form extremely high molecular weight particles containing centers of electron density. Tendrils of DNA, primarily duplex, radiate outward from these centers. 5. The aggregation may be reversed by the removal of magnesium. The intramolecular condensation may be at least partly reversed by increasing the Mg(ClO4)2 concentrations to saturating levels.

Coliphages↗

PubMed1979

Ultrastructural examination of urinary sediment. Value in renal amyloidosis.

Examination of urinary sediment has been recommended as a useful diagnostic aid for renal amyloidosis. This procedure was evaluated in the cases of 57 patients, including 11 with proven renal amyloidosis and 13 considered very likely to have the disease. At least three types of urinary fibrillar material were observed: 10-12-nm-diameter fibrils similar to amyloid; 7-10-nm-diameter fibrils with characteristics of intracellular tonofibrils; and 15-30-nm-diameter fibrils suggestive of fibrin tendrils. Only four of 24 patients who had renal amyloidosis proven or suspected had amyloid-like fibrils in the urinary sediment, while four control patients, including three with diabetic nephropathy, had similar fibrils. Sixty-eight per cent of all urines contained material consistent with tonofibrils. Ultrastructural examination of urinary sediment as a diagnostic aid for renal amyloidosis lacks sensitivity and specificity and has very limited clinical value.

Amyloid↗