Zygotic embryo development in Daucus carota

1996 ◽  
Vol 74 (7) ◽  
pp. 990-998 ◽  
Author(s):  
Sharon Lackie ◽  
Edward C. Yeung
Keyword(s):  
Cell Wall ◽  
Basal Cell ◽  
Daucus Carota ◽  
Staining Pattern ◽  
Zygotic Embryo ◽  
Nile Red ◽  
Cell Lineage ◽  
Terminal Cell ◽  
Zygotic Embryogenesis ◽  
Cotyledon Stage

After fertilization, the zygote divided unequally, giving rise to a larger basal cell and a smaller terminal cell. Derivatives from the basal cell gave rise to the suspensor and the terminal cell gave rise to the embryo proper. The suspensor usually consisted of a uniseriate file of 10–12 cells. However, additional anticlinal and oblique divisions resulted in some suspensors having more than one cell file. Cuticular substance was not present in the suspensor cell wall. The embryo proper was derived from the terminal four cells of the eight-celled embryo. The protoderm differentiated first, and subsequent to its formation cuticular substance could be detected in the outer tangential walls using the Nile red stain. This staining pattern intensified as the embryo matured. A defined cell lineage was not associated with tissue and meristem differentiation. Meristems began to form at the heart stage and became clearly defined at the late heart – early cotyledon stage. Keywords: cuticular material, Daucus carota, fluorescence, suspensor, zygotic embryogenesis.

Embryo and endosperm development in coriander (Coriandrum sativum)

Botany ◽  
2011 ◽  
Vol 89 (4) ◽  
pp. 263-273 ◽  
Author(s):  
Edward C. Yeung ◽  
Steve Bowra
Keyword(s):  
Basal Cell ◽  
Structural Changes ◽  
Cell Lineage ◽  
Endosperm Development ◽  
Coriandrum Sativum ◽  
Terminal Cell ◽  
Primary Endosperm Nucleus ◽  
Cell Degeneration ◽  
Storage Products ◽  
And Storage

Coriander ( Coriandrum sativum L.) seeds are rich in lipids and are potentially important sources of oils for industrial use. The objective of this study was to determine the details of embryo and endosperm development and the sites of storage reserves using microscopy and histochemistry. In coriander, the zygote divides unequally, giving rise to a large basal cell and a smaller terminal cell. Subsequent divisions in the basal cell result in the formation of a suspensor, and divisions in the terminal cell give rise to cells of the embryo proper. A defined cell lineage is absent in the formation of the proembryo. Contrary to other flowering plants, the suspensor persists as the embryo matures and storage products are present within the cytoplasm of the suspensor cells. After fertilization, the primary endosperm nucleus divides rapidly, resulting in a large syncytium of nuclei and cytoplasm. The rapid nuclear divisions occur prior to the first division of the zygote. Cellularization of the endosperm occurs soon after. Within the developing seed, the endosperm can be separated into two main regions, i.e., the “embryo surround region” (ESR) of endosperm and the persistent endosperm. The endosperm cells in these two regions have different cell fates and storage products. In the ESR, the endosperm cells undergo distinct structural changes and are destined to degenerate. These endosperm cells produce a significant amount of polysaccharides and these materials appear to aid in cell separation prior to cell degeneration. At the boundary of the ESR, the endosperm cells are partially degenerated with a large accumulation of lipids. The bulk of the endosperm cells next to the seed coat persist and they are responsible for the production and accumulation of storage lipids and proteins.

The Dog as a Spontaneous Model to Study the Mammary Myoepithelial Basal Cell Lineage and its Role in Mammary Carcinogenesis

2014 ◽  
Vol 150 (1) ◽  
pp. 86
Author(s):  
R. Rasotto ◽  
M. Goldschmidt ◽  
M. Castagnaro ◽  
P. Carnier ◽  
D. Caliari ◽  
...  
Keyword(s):  
Basal Cell ◽  
Cell Lineage ◽  
Mammary Carcinogenesis

scholarly journals Engineering of a Human Vaginal Lactobacillus Strain for Surface Expression of Two-Domain CD4 Molecules

2008 ◽  
Vol 74 (15) ◽  
pp. 4626-4635 ◽  
Author(s):  
Xiaowen Liu ◽  
Laurel A. Lagenaur ◽  
Peter P. Lee ◽  
Qiang Xu
Keyword(s):  
Cell Wall ◽  
Expression System ◽  
Significant Risk ◽  
Surface Expression ◽  
Heterosexual Transmission ◽  
Terminal Cell ◽  
Heterologous Proteins ◽  
Major Step ◽  
Sorting Signal ◽  
C Terminus

ABSTRACT Women are at significant risk of heterosexually transmitted human immunodeficiency virus (HIV) infection, with the mucosal epithelium of the cervix and vagina serving as a major portal of entry. The cervicovaginal mucosa naturally harbors dynamic microflora composed predominantly of lactobacilli, which may be genetically modified to serve as a more efficient protective barrier against the heterosexual transmission of HIV. We selected a vaginal strain of Lactobacillus, L. jensenii 1153, for genetic modification to display surface-anchored anti-HIV proteins. Genomic sequencing analyses revealed that L. jensenii 1153 encodes several unique high-molecular-weight cell wall-anchored proteins with a C-terminal cell wall sorting LPQTG motif. In this report, we employed these proteins to express a surface-anchored two-domain CD4 (2D CD4) molecule in L. jensenii 1153. Our studies indicated that the C-terminal cell wall sorting signal LPQTG motif alone is insufficient to drive the surface expression of heterologous proteins, and the display of surface-anchored 2D CD4 molecules required native sequences of a defined length upstream of the unique C-terminal LPQTG cell wall sorting signal and the positively charged C terminus in a Lactobacillus-based expression system. The modified L. jensenii strain displayed 2D CD4 molecules that were uniformly distributed on bacterial surfaces. The surface-anchored 2D CD4 molecule was recognized by a conformation-dependent anti-CD4 antibody, suggesting that the expressed proteins adopted a native conformation. The establishment of this Lactobacillus-based surface expression system, with potential broad applicability, represents a major step toward developing an inexpensive yet durable approach to topical microbicides for the mitigation of heterosexual transmission of HIV and other mucosally transmitted viral pathogens.

Identification of the cell lineage at the origin of basal cell carcinoma

2010 ◽  
Vol 12 (3) ◽  
pp. 299-305 ◽  
Author(s):  
Khalil Kass Youssef ◽  
Alexandra Van Keymeulen ◽  
Gäelle Lapouge ◽  
Benjamin Beck ◽  
Cindy Michaux ◽  
...  
Keyword(s):  
Basal Cell Carcinoma ◽  
Cell Carcinoma ◽  
Basal Cell ◽  
Cell Lineage

scholarly journals Developmental changes of catalase and superoxide dismutase isoenzymes in zygotic and somatic embryos of horse chestnut

1998 ◽  
Vol 25 (8) ◽  
pp. 909 ◽  
Author(s):  
F. Bagnoli ◽  
M. Capuana ◽  
M. L. Racchi
Keyword(s):  
Superoxide Dismutase ◽  
Somatic Embryogenesis ◽  
Somatic Embryo ◽  
Zygotic Embryo ◽  
Electrophoretic Analysis ◽  
Horse Chestnut ◽  
Zygotic Embryogenesis ◽  
Native Page ◽  
Cat Isoforms

Catalase (CAT) and superoxide dismutase (SOD), two of the major antioxidant enzyme systems, were examined by native PAGE at different stages of zygotic and somatic embryogenesis of horse chestnut (Aesculus hippocastanum L.). During both zygotic and somatic embryogenesis, CAT and SOD specific activities increased, but electrophoretic analysis revealed remarkable differences in the isoenzyme patterns. Two CAT isoforms were differentially present during zygotic embryogenesis. The transition from the fast to the slow migrating form occurred in July, approximately 2 months after pollination. In contrast to zygotic, the two isoforms were continuously detectable during somatic embryo-genesis. In fact, with the exception of the callus stage, in which only one form was present, both of the CAT isoforms are equally active during the somatic embryo development. Unlike CAT, all SOD isoenzymes, one Mn-SOD and five Cu/Zn-SODs, were present during all the stages of zygotic embryo formation, but only Mn-SOD and an Fe-SOD were detected during somatic embryogenesis. These results suggest the occurrence of oxidative stress conditions during in vitro culture which, in horse chestnut, could account for the difficulties observed in the development of the somatic embryo into a plantlet.

scholarly journals Embryo Development of Cypripedium formosanum in Relation to Seed Germination In Vitro

2005 ◽  
Vol 130 (5) ◽  
pp. 747-753 ◽  
Author(s):  
Yung-I Lee ◽  
Nean Lee ◽  
Edward C. Yeung ◽  
Mei-Chu Chung
Keyword(s):  
Seed Germination ◽  
Embryo Development ◽  
Developmental Stages ◽  
Culture Media ◽  
Nile Red ◽  
Germination Percentage ◽  
Zygotic Embryogenesis ◽  
Seed Collection ◽  
Significant Difference

This investigation documents the key anatomical features in embryo development of Cypripedium formosanum Hayata, in association with the ability of embryos to germinate in vitro, and examines the effects of culture media and seed pretreatments on seed germination. A better understanding of zygotic embryogenesis for the Cypripedium L. species would provide insights into subsequent germination events and aid in the in vitro propagation of these endangered species. In seeds collected at 60 days after pollination (DAP), soon after fertilization, no germination was recorded. The best overall germination was found at 90 DAP (≈70%), at which time early globular to globular embryos with a single-celled suspensors can be observed. After 135 DAP, the seeds germinated poorly. At this time the inner integument shrinks and forms a tight layer, which encloses the embryo, the so-called “carapace.” Using Nile red stain, a cuticular substance was detected in the carapace, which may play a role in the impermeability of the mature seed and may help the seeds survive in the stringent environment. At maturity (after 210 DAP), the embryo proper has an average size of eight cells along its length and six cells across the width. Lipids and proteins are the main storage products within the embryo. To improve seed germination, experiments were conducted to test the suitability of various media and pretreatments of seeds. When different media were used, except for the Harvais medium at 120 DAP, there was no significant difference in seed germination at three different developmental stages tested. Soaking mature seeds in 1% NaOCl or treating them with ultrasound may slightly increase the germination percentage. For seed germination, our results indicate that the timing of seed collection outweighs the composition of medium and the seed pretreatments.

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