Anatomical observations on somatic embryogenesis from scutellar tissues of immature zygotic embryos of Triticum aestivum

Somatic embryos were observed as early as six days after subculturing immature embryos of Triticum aestivum L. (cvs Froid-Centurk and Helge) in vitro on 2,4-dichloro-phenoxyacetate-containing nutrient media. Embryo formation followed three pathways, each involving one of the scutellum's three basic tissue systems: dermal, ground and vascular.
(1) Single epithelial layer cells divided tangentially to give pseudothallus-like structures which, through radial and oblique divisions, assumed polar, proembryoid symmetry.
(2) In actively dividing ground tissues, localized asymmetrical division in some cells resulted in proembryoids. When contiguous with each other, the proembryoids could be identified as a proembryonic mass.
(3) Oblique divisions in some cells of the scutellum's procambium resulted in daughter cells of unequal size, from the smaller of which the embryoid's root would eventually form.     

Single-cell analysis of embryoids reveals lineage diversification roadmaps of early human development

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Ginsenoside Rg1 facilitates neural differentiation of mouse embryonic stem cells via GR-dependent signaling pathway

Ginsenoside Rg1, a steroidal saponin of high abundance in ginseng, possesses the neuroprotective effects. In this study, we tried to explore the effect of Rg1 on promoting differentiation of mouse embryonic stem (ES) cells towards the neuronal lineage and its potential role involved in glucocorticoid receptor (GR) activation. Rg1 treatment induced a remarkable increase in the population of neuron-like cells in a time-dependent manner. More than 80% of Rg1-treated embryoid bodies (EBs) differentiated into neuron-like cells on d 8 + 10. Furthermore, the gradually increased protein expression of neurofilament (NEFM) and β-tubulin III (a neuronal specific protein) was determined. GR expression gradually increased during the differentiation course. RU486, an antagonist of GR, could efficiently block the neurogenesis-promoting activity of Rg1. On the other side, Rg1 stimulated the phosphorylation of ERK1/2 and Akt at different time points through GR activation-dependent mechanisms. Treatment of both U0126 (an inhibitor of MEK) and LY294002 (an inhibitor of PI3 K), hampered the neuronal differentiation induced by Rg1. Meantime, U0126 further decreased Rg1-induced p-Akt expression. In conclusion, Rg1 possesses the effects on inducing differentiation of mouse ES cells into neurons in vitro via the GR-MEK-ERK1/2-PI3 K-Akt signaling pathway.     

Induction of haploid callus and embryogenesis in in vitro cultured anthers of mulberry (Morus indica)

Anthers of Morus indica L., with microspores at the uninucleate stage were cultured; and the influence of temperature and kinetin pretreatment on induction of androgenic calluses was examined. The effects of various pretreatments revealed that 24 h cold pretreatment increased the percentage of cultures inducing callus. First microspore division was observed after 16 to 20 days of culture. Th anthers split and developed embryogenic calluses on MB medium supplemented with NAA (0.5 mg l^–1 and BA (1.0 mg l^–1)) using 8% sucrose. Rhizogenesis was induced on medium supplemented with NAA and BA (each 0.5 mg l^–1) with reduced myo-inositol (75 mg l^–1). Cytological study of induced roots confirmed the haploid nature of calluses. Different type of embryos were initiated upon transfer of calluses to medium supplemented with NAA, BA (each 0.5 mg l^–1), 2,4-d (1.0 mg l^–1) and PVP (600 mg l^–1). These embryoids further developed roots on removal of 2,4-d from the medium and developed precociously without developing cotyledons and formed elongated shoots.Abbreviations BA 6 benzylaminopurine - 2,4-d 2,4-dichlorophenoxyacetic acid - FAA formalin: Acetic acid: Alcohol - GA₃ gibberellic acid - IBA indole-3-butyric acid - MB modifed Bourgin (Qian et al., 1982) - NAA 1-naphthalene acetic acid - PVP polyvinylpyrrolidone - RFS-135 rainfed selection 135 - SE standard error     

Embryoid formation in alfalfa cell suspension cultures from different plants

Summary Cell suspension cultures were initiated from shoot tips of nine plants of alfalfa. Our results indicated that considerably different nutritional conditions were required to induce embryogenesis in the cell cultures derived from these plants. By proper adjustment of the hormone level and mineral salt concentration it was possible to induce embryogenesis in all of the nine cultures tested. The embryoids from seven of the nine cultures were able to develop into plants.     

In vitro attachment and symmetry breaking of a human embryo model assembled from primed embryonic stem cells

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