The development of cells in the coenocytic endosperm of the African blood lily Haemanthus Katherinae

1978 ◽  
Vol 56 (5) ◽  
pp. 483-501 ◽  
Author(s):  
William Newcomb
Keyword(s):  
Embryo Sac ◽  
Transfer Cell ◽  
Central Vacuole ◽  
Free Wall ◽  
Cell Type ◽  
Wall Ingrowths ◽  
Stage Of Development ◽  
Cellular Endosperm ◽  
Free Cells ◽  
Large Central Vacuole

The endosperm of the African blood lily Haemanthus Katherinae Bak. follows the helobial pattern of development in which two chambers of endosperm are formed. In the earliest observed stage of development a large micropylar chamber and a smaller dome-shaped chalazal chamber of endosperm are present. Both are coenocytic and contain wall ingrowths of the transfer cell type along the embryo sac wall. Freely growing walls grow centripetally from the embryo sac wall, branch, and eventually meet, forming a layer of cells along the embryo sac wall. This process occurs first in the micropylar chamber. After four or more layers of endosperm cells are present, phragmoplasts form in association with karyokinesis and give rise to cross walls situated between the freely growing walls. When 10 or more layers of endosperm cells are present, free wall-less cells are present in the central vacuole near the edge of the cellular endosperm of the micropylar chamber. The free cells originate from mitosis of nuclei at the inner wall-less edge of the endosperm and the subsequent pinching off and release of the free cells into the large central vacuole. The free cells may undergo karyokinesis and become binucleate. The chalazal chamber of endosperm also becomes cellular by means of freely growing walls.

Transfer cells in the sporophyte–gametophyte junction of Lycopodium appressum

1991 ◽  
Vol 69 (1) ◽  
pp. 222-226 ◽  
Author(s):  
R. L. Peterson ◽  
D. P. Whittier
Keyword(s):  
Key Words ◽  
Transfer Cells ◽  
Central Vacuole ◽  
Wall Ingrowths ◽  
Narrow Wall ◽  
Membrane Apparatus ◽  
Large Central Vacuole ◽  
Sporophyte Development ◽  
Thickened Wall ◽  
Young Sporophytes

The sporophyte–gametophyte interface in cultured Lycopodium appressum gametophytes consists of a sporophytic foot embedded in gametophyte tissue. Foot cells and contiguous gametophytic cells develop extensive wall ingrowths, making them transfer cells. Transfer cells in the foot of young sporophytes and in adjacent gametophyte cells have elongated, narrow wall ingrowths forming a labrynthine wall–membrane apparatus, numerous mitochondria, and plastids with variable amounts of starch. Transfer cells in older interfaces have thickened wall ingrowths, few mitochondria, plastids with numerous plastoglobuli and little starch, and a large central vacuole. Plasmodesmata do not develop between cells of sporophyte and gametophyte generations and these are, therefore, isolated symplastically during all stages of sporophyte development. Key words: Lycopodium, foot, haustorium, transfer cells, ultrastructure.

THE DEVELOPMENT OF THE BLUEBERRY SEED

1957 ◽  
Vol 35 (2) ◽  
pp. 139-153 ◽  
Author(s):  
Hugh P. Bell
Keyword(s):  
Seed Development ◽  
Seed Coat ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Homogeneous Plasma ◽  
Stage Of Development ◽  
Micropylar Endosperm ◽  
Mature Seeds ◽  
Number Of Seeds

Seed development was followed from fertilization to maturity. Pollen tubes required about 4 days to grow from stigma to ovule. In some plants, particularly bagged ones, nucellar cells remained alive and contents of the embryo sac degenerated. Many ovules did not develop. Seeds were counted and sorted in a random representative collection of 1075 berries. The average number of seeds per berry was 64.2. Of these 49.9 (or 77.7%) were imperfect. More complete pollination increased the percentage of normally developing ovules. Development of perfect seeds followed a familiar pattern. Unfamiliar features were noted as follows: 1. Degeneration of cells at both micropylar and chalazal ends resulted in a homogeneous plasma. This plasma formed strands across haustoria and almost completely surrounded the zygote. 2. Micropylar endosperm cells formed a dense plug. Developing embryos may have had difficulty in penetrating this plug. 3. Many embryos had died at some stage of development. 4. A conspicuous integumentary tapetum was present until the endosperm was about half its final size.Embryo development was the "soland" type. Mature seeds were "axile linear". Imperfect seeds were chiefly of two types: (a) medium sized and solid with middle integumentary layers lignified, or (b) small and collapsed with all tissues inside seed coat disintegrated. No imperfect seed had an embryo.

Primitive Erythroid Progenitors Are Regulated by Hypoxia and Display An Aerobic Glycolytic Metabolic Profile,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3159-3159
Author(s):  
Margaret H. Baron ◽  
Joan Isern ◽  
Stuart T. Fraser ◽  
Zhiyong He ◽  
Avi Ma'ayan ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Mammalian Cells ◽  
Enrichment Analysis ◽  
Yolk Sac ◽  
Negative Regulator ◽  
Erythroid Cell ◽  
Cell Type ◽  
Strong Basis ◽  
Stage Of Development ◽  
Erythroid Development

Abstract Abstract 3159 Primitive erythroblasts (EryP) are the first cell type specified from mesodermal progenitors in the mammalian embryo. They are found in the mouse yolk sac from embryonic day (E) ∼E7.5–8.5 and, as circulation initiates, they begin to differentiate to erythroblasts that enter the bloodstream and continue to mature in a stepwise, synchronous fashion until their enucleation several days later. We have purified these first hematopoietic-committed progenitors from staged embryos based on the expression of a nuclear GFP transgene that is expressed specifically within the EryP lineage as early as E7.5. Genome-wide expression profiling allowed us to define the transcriptome from each stage of development and revealed highly dynamic changes during the progression from progenitor to maturing erythroblast. We focused on the emergence of EryP progenitors in the yolk sac and on the transition to circulation stage, when progenitor activity is lost and a peak is observed in the number of genes whose expression changes. TRANSFAC analysis of promoters of differentially expressed genes allowed us to identify candidate transcriptional regulators, some of which have not previously been implicated in erythroid development (e.g. Nkx3.1, known previously as a regulator of prostate stem cells). We designed experiments to test predictions from our microarray analysis and found that EryP progenitor numbers are regulated by TGF-beta1 and hypoxia. In most mammalian cells, the response to hypoxia is mediated by the transcription factor HIF-1. Hif-1 is apparently not expressed in EryP. Howver, Hif3a/Ipas, a Hif-1 target gene that encodes a dominant negative regulator of HIFs and that is thought to function as a feedback regulator in response to hypoxia, is expressed in EryP as early as E7.5 and is upregulated as the cells mature. These findings suggest that the response to hypoxia by EryP may involve a pathway that is distinct from that of most other cells. EryP progenitors express genes associated with aerobic glucose metabolism (the Warburg effect), a phenotype characteristic of cancer and other rapidly proliferating cells. Whether this glycolytic profile reflects the energy needs of these cells or a more unique feature of primitive erythropoiesis is under investigation. Currently we are using computational methods to identify transcription factor (ChEA, ChIP Enrichment Analysis) and kinase (KEA, Kinase Enrichment Analysis) networks that may play a role in the regulation of primitive erythroid development. This study is the first lineage specific transcription profiling of a differentiating cell type in the early mouse embryo and will provide a strong basis for future work on normal erythropoiesis throughout ontogeny. It may also help guide efforts to direct the differentiation of stem/progenitor and cells of other lineages to an erythroid cell fate. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Placenta of Physcomitrium patens: Transfer Cell Wall Polymers Compared across the Three Bryophyte Groups

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 378
Author(s):  
Jason S. Henry ◽  
Karen S. Renzaglia
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cell Wall Composition ◽  
Transfer Cells ◽  
Primary Cell ◽  
Transfer Cell ◽  
Primary Cell Wall ◽  
Slight Variation ◽  
Wall Ingrowths ◽  
Cell Wall Polymers

Following similar studies of cell wall constituents in the placenta of Phaeoceros and Marchantia, we conducted immunogold labeling TEM studies of Physcomitrium patens to determine the composition of cell wall polymers in transfer cells on both sides of the placenta. Sixteen monoclonal antibodies were used to localize cell wall epitopes in the basal walls and wall ingrowths in this moss. In general, placental transfer cell walls of P. patens contained fewer pectins and far fewer arabinogalactan proteins AGPs than those of the hornwort and liverwort. P. patens also lacked the differential labeling that is pronounced between generations in the other bryophytes. In contrast, transfer cell walls on either side of the placenta of P. patens were relatively similar in composition, with slight variation in homogalacturonan HG pectins. Compositional similarities between wall ingrowths and primary cell walls in P. patens suggest that wall ingrowths may simply be extensions of the primary cell wall. Considerable variability in occurrence, abundance, and types of polymers among the three bryophytes and between the two generations suggested that similarity in function and morphology of cell walls does not require a common cell wall composition. We propose that the specific developmental and life history traits of these plants may provide even more important clues in understanding the basis for these differences. This study significantly builds on our knowledge of cell wall composition in bryophytes in general and in transfer cells across plants.

scholarly journals Morphology of Postpollination Fruit Abortion in Pecan

1995 ◽  
Vol 120 (3) ◽  
pp. 446-453
Author(s):  
I.E. Yates ◽  
Darrell Sparks
Keyword(s):  
Embryo Development ◽  
Direct Evidence ◽  
Embryo Sac ◽  
Growing Season ◽  
Carya Illinoensis ◽  
Egg Apparatus ◽  
Cellular Endosperm ◽  
Fruit Abortion

Anatomy of normal and abortive fruit was compared at each of the three postpollination fruit drops characteristic of pecan [Carya illinoensis (Wangenh.) C. Koch]. Size differences between normal and abortive fruit decreased during the growing season, but differences in ovule size between normal and abortive fruit increased. During Drop II, normal and abortive fruit had an integument enclosing a massive nucellus in which an embryo sac was embedded, but embryo sac shape and constituents differed. Embryo sacs were distended in normal fruit and contained a definitive zygote as evidence of fertilization, i.e., union of egg and sperm. In contrast, embryo sacs in abortive fruit were shriveled and contained an egg apparatus as in unfertilized distillate flowers. During Drop III, normal and abortive fruit had a similar multicellular embryo. The nucellus in normal fruit was reduced to a cap at the micropyle region and cellular endosperm was evident. In contrast, the nucellus in abortive fruit was abundant and cellular endosperm was not evident. During Drop IV, embryo development in abortive fruit lagged behind that of normal fruit. Thus, we present the first direct evidence that aborted pecans deviate from normal fruit by an absence of a zygote at Drop II, a deficiency in cellular endosperm at Drop III, and a delay in embryo development at Drop IV.

Cellularization of the female gametophyte in Ranunculus sceleratus

1989 ◽  
Vol 67 (5) ◽  
pp. 1325-1330 ◽  
Author(s):  
N. N. Bhandari ◽  
P. Chitralekha
Keyword(s):  
Female Gametophyte ◽  
Horizontal Cell ◽  
Embryo Sac ◽  
Cell Plate ◽  
Mitotic Division ◽  
The Other ◽  
Central Vacuole ◽  
Distinct Cell ◽  
Antipodal Cells ◽  
Vertical Cell

Wall formation in Ranunculus sceleratus takes place simultaneously at the micropylar and chalazal poles of the embryo sac. During the last (third) mitotic division resulting in an eight-nucleate embryo sac, three distinct cell plates are formed at either pole. Of the three cell plates, CPI (horizontal), CPE (oblique), and CPIII (vertical), the first two are formed between the separating chromatin masses of the two dividing nuclei. CPIII (vertical cell plate) arises subsequently between the first two plates. CPI (horizontal cell plate) extends perpendicular to the long axis of the embryo sac to separate the central vacuole and one nucleus (polar) from the quartet of nuclei. The other two cell plates extend simultaneously between the three remaining nuclei; CPII (oblique plate) cuts off one of the nuclei while CPIII (vertical cell plate) separates the other two. Consequently, the egg apparatus, central cell with two polar nuclei, and three antipodal cells are formed.

Ultrastructure of mimosa leaflet and pulvinule

1978 ◽  
Vol 36 (2) ◽  
pp. 422-423
Author(s):  
V. A. Stein-Margolina
Keyword(s):  
Thin Layer ◽  
Ruthenium Red ◽  
Central Vacuole ◽  
Lower Wall ◽  
Mimosa Pudica ◽  
Lower Zone ◽  
Lower Epidermis ◽  
Before And After ◽  
Large Central Vacuole ◽  
Light Stimuli

The ultrastructure of leaflet and tertiary pulvini (pulvinule) of the sensitive plant, Mimosa pudica L., as well as the distribution of ATPase were studied before and after stimulation.There are two zones in the majority of upper epidermis cells of the leaflet (Fig. 1). The upper zone contains a thin layer of cytoplasma, a large central vacuole and much tannin. The lower zone of these cells is electron-transparent and has a lens-like shape. It is filled with fibrillar-foamy material (Fig. 2). “The foam” fibrills are 30-100 Å in diameter. “The foam” is stained with ruthenium red and is supposed to be a mucilaginous inner (lower) wall of the epidermal cell. The cells of the lower epidermis of the leaflet and the pulvinule epidermis do not contain “the foam”. The lens-shaped foamy material might focus light, promote its reception and transfer the light stimuli within the leaflets and pulvini, thus regulating the heliotropic and nyctinastic position of the leaf itself.

scholarly journals Current Progress in Tonoplast Proteomics Reveals Insights into the Function of the Large Central Vacuole

2013 ◽  
Vol 4 ◽  
Author(s):  
Oliver Trentmann ◽  
Ilka Haferkamp
Keyword(s):  
Central Vacuole ◽  
Large Central Vacuole

Genome Expression Profiling of the First Hematopoietic Progenitors of the Mouse Embryo.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2536-2536
Author(s):  
Margaret H. Baron ◽  
Joan Isern ◽  
Stuart T. Fraser ◽  
Zhiyong He ◽  
David Tuck ◽  
...  
Keyword(s):  
Mouse Embryo ◽  
Expression Profiling ◽  
Yolk Sac ◽  
Transcriptional Networks ◽  
Cell Type ◽  
Hematopoietic Progenitors ◽  
Genome Expression ◽  
Stage Of Development ◽  
Gfp Reporter ◽  
Major Cluster

Abstract Abstract 2536 Poster Board II-513 The transcriptional networks that regulate lineage commitment and expansion of the earliest hematopoietic progenitors in the mammalian embryo have not been well studied, due to a lack of methods for isolating these cells. We have begun to address this problem by purifying the first hematopoietic-committed progenitors in the mouse embryo based on expression of a human ε-globin::H2B-EGFP transgene that is expressed exclusively within the primitive erythroid (EryP) lineage, as early as embryonic day (E) 7.5. EryP are the first lineage-specific cell type to form in the embryo. They arise in large numbers from yolk sac-derived progenitors at the end of gastrulation, enter the circulation as nucleated cells soon thereafter, and continue to mature in a stepwise, synchronous fashion until they enucleate. The early and lineage specific expression of the GFP reporter allowed us to isolate not only circulating EryP (E9.5-E11.5) but also a population from dispersed E7.5-8.5 embryos that is enriched in EryP progenitors. Genome expression profiling allowed us to define the transcriptome from each stage of development and revealed highly dynamic changes during the progression from progenitor to maturing erythroblast. Hierarchical clustering analysis was used to organize genes on the basis of overall similarity in expression patterns; six major cluster patterns were identified. Genes within these clusters comprised distinct functional classes. For example, particularly prominent increases in expression were detected for genes involved in ribosome biogenesis, translation, chromosome condensation, and autophagy. Genes that were downregulated included those involved in DNA replication, cell cycle, and nucleolar and organelle biogenesis. We have focused on the emergence of EryP in the yolk sac. Expression of Gata2 is high in the progenitor population at E7.5 and decreases dramatically by E8.5. In contrast, Gata1, Scl, and Eklf are all upregulated during maturation of EryP progenitors, suggesting that these transcription factors have distinct functions during primitive erythropoiesis. Consistent with expression of the GFP reporter as early as E7.5, we find that endogenous mouse embryonic globin genes are also expressed at this stage. Therefore, globin gene expression is an early feature of EryP development. Analysis of promoters of differentially expressed genes allowed us to identify candidate transcriptional regulators, some of which have not previously been implicated in erythroid development. This is the first lineage specific transcription profiling of a differentiating hematopoietic cell type in the early mouse embryo. While we have focused on the development of EryP, insights from this study should have broader relevance to the definitive erythroid lineage. Disclosures: No relevant conflicts of interest to declare.

Regulation of Primitive Erythroid Progenitor Development

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1211-1211
Author(s):  
Margaret H. Baron ◽  
Andrei Vacaru ◽  
Joan Isern ◽  
Anna-Katerina Hadjantonakis ◽  
Dmitri Papatsenko ◽  
...  
Keyword(s):  
Conflicts Of Interest ◽  
Enrichment Analysis ◽  
Yolk Sac ◽  
Erythroid Cell ◽  
Cell Type ◽  
Erythroid Progenitor ◽  
Strong Basis ◽  
Stage Of Development ◽  
Erythroid Development ◽  
Mouse Lines

Abstract Abstract 1211 Primitive erythroid cells (EryP) are the first hematopoietic cell type to form in the mammalian embryo. Their progenitors are found in the mouse yolk sac from embryonic day (E) ∼E7.5–8.5 and, as circulation initiates, they begin to differentiate, enter the bloodstream and continue to mature in a stepwise, synchronous fashion until their enucleation several days later. We purified these first hematopoietic-committed progenitors from staged embryos based on the expression of a nuclear (histone H2B fusion) GFP transgene that is expressed specifically within the EryP lineage as early as E6.75. Their very high proliferative capacity can be easily followed using the H2B-GFP reporter and with vital dyes, and we are using these and other approaches to study their cell cycle properties. We have now generated analogous mouse lines expressing different color fluorescent reporters (CFP, mCherry), to permit crosses with other GFP or YFP expressing mouse lines so that simultaneous imaging of (for example) EryP and endothelial cell development can be followed in real time. Genome-wide expression profiling (Isern et al., Blood 117:4924–4934, 2011) allowed us to define the transcriptome from each stage of development of FACS-sorted (GFP+) cells, including progenitor stages, and revealed highly dynamic changes during the progression from progenitor to maturing erythroblast. We focused on the emergence of EryP progenitors in the yolk sac and on the transition to circulation stage, when progenitor activity is lost and a peak is observed in the number of genes whose expression changes. Promoter analysis of differentially expressed genes allowed us to identify candidate transcriptional regulators, some of which have not previously been implicated in erythroid development (e.g. Nkx3.1, known previously as a regulator of prostate stem cells). We have found that the Wnt signaling pathway is active in EryP progenitors; studies to evaluate the function of this pathway are in progress. EryP progenitors express genes associated with anaerobic glucose metabolism (the Warburg effect), a phenotype characteristic of cancer and other rapidly proliferating cells. Interestingly, we have identified three clusters enriched in genes related to mitochondrial structure/function; genes in these clusters are sequentially expressed. Analysis of these changes may provide insights into whether the glycolytic profile of EryP reflects the energy needs of these cells or a more unique feature of primitive erythropoiesis. Currently we are using computational methods to identify transcription factor (ChEA, ChIP Enrichment Analysis) and kinase (KEA, Kinase Enrichment Analysis) networks that may play a role in the regulation of primitive erythroid development. This is the first lineage specific transcription profiling of a differentiating cell type in the early mouse embryo and will provide a strong basis for future work on normal erythropoiesis throughout ontogeny. It may also help guide efforts to direct the differentiation of stem/progenitor and cells of other lineages to an erythroid cell fate. Disclosures: No relevant conflicts of interest to declare.

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