scholarly journals From centriole biogenesis to cellular function: Centrioles are essential for cell division at critical developmental stages

Cell Cycle ◽  
2008 ◽  
Vol 7 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Ana Rodrigues-Martins ◽  
Maria Riparbelli ◽  
Giuliano Callaini ◽  
David M. Glover ◽  
Monica Bettencourt-Dias
Keyword(s):  
Cell Division ◽  
Developmental Stages ◽  
Cellular Function

Floral development of Aponogeton natans and A. undulatus

1977 ◽  
Vol 55 (9) ◽  
pp. 1106-1120 ◽  
Author(s):  
V. Singh ◽  
R. Sattler
Keyword(s):  
Cell Division ◽  
Developmental Stage ◽  
Floral Development ◽  
Developmental Stages ◽  
Point Of View ◽  
Stages Of Development ◽  
The Third ◽  
Procambial Strand ◽  
Tunica Layer

The primordia of the floral appendages are initiated in an acropetal succession. Members of the same whorl appear nearly simultaneously. The gynoecial whorl and the two staminal whorls are trimerous, whereas the perianth consists only of two anteriolateral tepals. However, the posterior (adaxial) tepal may be present as an extremely reduced buttress whose growth becomes arrested immediately after its inception. If this somewhat questionable tepal rudiment is included we have a perfectly trimerous and tetracyclic flower with alternation of successive whorls. Subtending bracts of the flowers are completely missing in all developmental stages. While the tepal primordia are dorsiventral from their inception, the stamen and pistil (carpel) primordia originate as hemispherical mounds which become dorsiventral in subsequent stages of development. Each pistil (carpel) primordium becomes horseshoe shaped. As the margins grow up and contact they fuse postgenitally. No cross zone is formed. Placentation is submarginal. In A. natans eight ovules are formed and in A. undulatus only two arise; all ovules are bitegmic. The floral apices have a two-layered tunica up to the stage of pistil formation. The inception of all floral appendages (including the ovules) occurs by periclinal cell division in the second tunica layer. The third layer (corpus) may contribute to the formation of the stamens and pistils. Each appendage primordium receives only one procambial strand which begins to differentiate after the inception of the primordium. The questionable rudimentary tepal buttress lacks a procambial strand. Apparently it does not reach the developmental stage at which procambial induction occurs. From the point of view of floral development, the two species of Aponogeton differ drastically from members of the Alismatales studied so far. Among the Helobiae, the Aponogetonaceae appear to be most closely related to the Scheuchzeriaceae and the Juncaginaceae (Triglochinaceae).

Heteroblastic seedlings of green ash. III. Cell division activity and marginal meristems

1986 ◽  
Vol 64 (11) ◽  
pp. 2662-2668 ◽  
Author(s):  
E. K. Merrill
Keyword(s):  
Cell Division ◽  
Leaf Blade ◽  
Developmental Stages ◽  
Leaf Primordia ◽  
Leaf Margin ◽  
Green Ash ◽  
Histological Differentiation ◽  
Cell Counts ◽  
Histological Criteria ◽  
Early Developmental

The early developmental stages of simple and compound leaves of green ash (50–400 μm long) were used to relate cell division activity (mitotic index) to developing leaf form and histological differentiation. Densely cytoplasmic cells within cross-sectioned leaf primordia have higher mitotic indices than protodermal cells and other internal cells that are more vacuolate. Among densely cytoplasmic cells mitotic indices decrease from the primordial leaf margin toward the procambium. Ground meristem cells within three to five cell widths of the primordial margin had the highest mitotic indices. Actual cell counts indicate that densely cytoplasmic cells increase in number in areas of leaf blade or leaflet initiation more than do vacuolate cells or protodermal cells. It is proposed that marginal meristems defined by spatial and histological criteria are important in producing new cells that are the basis for the generation of simple and compound leaf forms.

scholarly journals Developmental series of gene expression clarifies maternal mRNA provisioning and maternal-to-zygotic transition in a reef-building coral

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Erin Chille ◽  
Emma Strand ◽  
Mayaan Neder ◽  
Valeria Schmidt ◽  
Madeleine Sherman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Division ◽  
Transcriptional Repression ◽  
Developmental Stages ◽  
Functional Enrichment ◽  
Peptide Transport ◽  
Maternal Mrna ◽  
Maternal To Zygotic Transition ◽  
Maternal Transcripts ◽  
Baseline Information

Abstract Background Maternal mRNA provisioning of oocytes regulates early embryogenesis. Maternal transcripts are degraded as zygotic genome activation (ZGA) intensifies, a phenomenon known as the maternal-to-zygotic transition (MZT). Here, we examine gene expression over nine developmental stages in the Pacific rice coral, Montipora capitata, from eggs and embryos at 1, 4, 9, 14, 22, and 36 h-post-fertilization (hpf), as well as swimming larvae (9d), and adult colonies. Results Weighted Gene Coexpression Network Analysis revealed four expression peaks, identifying the maternal complement, two waves of the MZT, and adult expression. Gene ontology enrichment revealed maternal mRNAs are dominated by cell division, methylation, biosynthesis, metabolism, and protein/RNA processing and transport functions. The first MZT wave occurs from ~4-14 hpf and is enriched in terms related to biosynthesis, methylation, cell division, and transcription. In contrast, functional enrichment in the second MZT wave, or ZGA, from 22 hpf-9dpf, includes ion/peptide transport and cell signaling. Finally, adult expression is enriched for functions related to signaling, metabolism, and ion/peptide transport. Our proposed MZT timing is further supported by expression of enzymes involved in zygotic transcriptional repression (Kaiso) and activation (Sox2), which peak at 14 hpf and 22 hpf, respectively. Further, DNA methylation writing (DNMT3a) and removing (TET1) enzymes peak and remain stable past ~4 hpf, suggesting that methylome programming occurs before 4 hpf. Conclusions Our high-resolution insight into the coral maternal mRNA and MZT provides essential baseline information to understand parental carryover effects and the sensitivity of developmental success under increasing environmental stress.

scholarly journals Physical constraints on early blastomere packings

2021 ◽  
Vol 17 (1) ◽  
pp. e1007994
Author(s):  
James Giammona ◽  
Otger Campàs
Keyword(s):  
Cell Division ◽  
Developmental Stages ◽  
Physical Parameters ◽  
Cell Stage ◽  
Physical Constraints ◽  
Equilibrium Dynamics ◽  
Deformable Particles ◽  
Early Embryos ◽  
Early Developmental Stages ◽  
Early Developmental

At very early embryonic stages, when embryos are composed of just a few cells, establishing the correct packing arrangements (contacts) between cells is essential for the proper development of the organism. As early as the 4-cell stage, the observed cellular packings in different species are distinct and, in many cases, differ from the equilibrium packings expected for simple adherent and deformable particles. It is unclear what are the specific roles that different physical parameters, such as the forces between blastomeres, their division times, orientation of cell division and embryonic confinement, play in the control of these packing configurations. Here we simulate the non-equilibrium dynamics of cells in early embryos and systematically study how these different parameters affect embryonic packings at the 4-cell stage. In the absence of embryo confinement, we find that cellular packings are not robust, with multiple packing configurations simultaneously possible and very sensitive to parameter changes. Our results indicate that the geometry of the embryo confinement determines the packing configurations at the 4-cell stage, removing degeneracy in the possible packing configurations and overriding division rules in most cases. Overall, these results indicate that physical confinement of the embryo is essential to robustly specify proper cellular arrangements at very early developmental stages.

scholarly journals Sequential steps for developmental arrest in Arabidopsis seeds

Development ◽  
2001 ◽  
Vol 128 (2) ◽  
pp. 243-252 ◽  
Author(s):  
V. Raz ◽  
J.H. Bergervoet ◽  
M. Koornneef
Keyword(s):  
Cell Division ◽  
Developmental Stages ◽  
Growth Arrest ◽  
Mature Embryo ◽  
Seed Maturation ◽  
Continuous Growth ◽  
Embryo Dormancy ◽  
Embryo Stage ◽  
Plant Embryo ◽  
Premature Germination

The continuous growth of the plant embryo is interrupted during the seed maturation processes which results in a dormant seed. The embryo continues development after germination when it grows into a seedling. The embryo growth phase starts after morphogenesis and ends when the embryo fills the seed sac. Very little is known about the processes regulating this phase. We describe mutants that affect embryo growth in two sequential developmental stages. Firstly, embryo growth arrest is regulated by the FUS3/LEC type genes, as mutations in these genes cause a continuation of growth in immature embryos. Secondly, a later stage of embryo dormancy is regulated by ABI3 and abscisic acid; abi3 and aba1 mutants exhibit premature germination only after embryos mature. Mutations affecting both developmental stages result in an additive phenotype and double mutants are highly viviparous. Embryo growth arrest is regulated by cell division activities in both the embryo and the endosperm, which are gradually switched off at the mature embryo stage. In the fus3/lec mutants, however, cell division in both the embryo and endosperm is not arrested, but rather is prolonged throughout seed maturation. Furthermore ectopic cell division occurs in seedlings. Our results indicate that seed dormancy is secured via at least two sequential developmental processes: embryo growth arrest, which is regulated by cell division and embryo dormancy.

Genome-wide transcript analysis of inflorescence development in wheat

Genome ◽  
2019 ◽  
Vol 62 (9) ◽  
pp. 623-633
Author(s):  
Dae Yeon Kim ◽  
Min Jeong Hong ◽  
Yong Weon Seo
Keyword(s):  
Cell Division ◽  
Developmental Stages ◽  
Early Stage ◽  
Meta Analysis ◽  
Development Stage ◽  
Yield Potential ◽  
Regulation Mechanism ◽  
Inflorescence Development ◽  
Grain Number Per Spike ◽  
Genechip Array

The process of inflorescence development is directly related to yield components that determine the final grain yield in most cereal crops. Here, microarray analysis was conducted for four different developmental stages of inflorescence to identify genes expressed specifically during inflorescence development. To select inflorescence-specific expressed genes, we conducted meta-analysis using 1245 Affymetrix GeneChip array sets obtained from various development stages, organs, and tissues of members of Poaceae. The early stage of inflorescence development was accompanied by a significant upregulation of a large number of cell differentiation genes, such as those associated with the cell cycle, cell division, DNA repair, and DNA synthesis. Moreover, key regulatory genes, including the MADS-box gene, KNOTTED-1-like homeobox genes, GROWTH-REGULATING FACTOR 1 gene, and the histone methyltransferase gene, were highly expressed in the early inflorescence development stage. In contrast, fewer genes were expressed in the later stage of inflorescence development, and played roles in hormone biosynthesis and meiosis-associated genes. Our work provides novel information regarding the gene regulatory network of cell division, key genes involved in the differentiation of inflorescence in wheat, and regulation mechanism of inflorescence development that are crucial stages for determining final grain number per spike and the yield potential of wheat.

scholarly journals Early postnatal irradiation‐induced age‐dependent changes in adult mouse brain: MRI based characterization

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Bo Xu Ren ◽  
Isaac Huen ◽  
Zi Jun Wu ◽  
Hong Wang ◽  
Meng Yun Duan ◽  
...  
Keyword(s):  
Cell Division ◽  
Radiation Exposure ◽  
Developmental Stages ◽  
Granule Cells ◽  
Brain Mri ◽  
Brain Regions ◽  
Hippocampal Neurogenesis ◽  
Cerebellar Hemisphere ◽  
Parietal Region ◽  
Olfactory Bulbs

Abstract Background Brain radiation exposure, in particular, radiotherapy, can induce cognitive impairment in patients, with significant effects persisting for the rest of their life. However, the main mechanisms leading to this adverse event remain largely unknown. A study of radiation-induced injury to multiple brain regions, focused on the hippocampus, may shed light on neuroanatomic bases of neurocognitive impairments in patients. Hence, we irradiated BALB/c mice (male and female) at postnatal day 3 (P3), day 10 (P10), and day 21 (P21) and investigated the long-term radiation effect on brain MRI changes and hippocampal neurogenesis. Results We found characteristic brain volume reductions in the hippocampus, olfactory bulbs, the cerebellar hemisphere, cerebellar white matter (WM) and cerebellar vermis WM, cingulate, occipital and frontal cortices, cerebellar flocculonodular WM, parietal region, endopiriform claustrum, and entorhinal cortex after irradiation with 5 Gy at P3. Irradiation at P10 induced significant volume reduction in the cerebellum, parietal region, cingulate region, and olfactory bulbs, whereas the reduction of the volume in the entorhinal, parietal, insular, and frontal cortices was demonstrated after irradiation at P21. Immunohistochemical study with cell division marker Ki67 and immature marker doublecortin (DCX) indicated the reduced cell division and genesis of new neurons in the subgranular zone of the dentate gyrus in the hippocampus after irradiation at all three postnatal days, but the reduction of total granule cells in the stratum granulosun was found after irradiation at P3 and P10. Conclusions The early life radiation exposure during different developmental stages induces varied brain pathophysiological changes which may be related to the development of neurological and neuropsychological disorders later in life.

scholarly journals Photoassimilate Regulation of Sorbitol and Sucrose Metabolism in Peach Fruit

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1116D-1116
Author(s):  
Riccardo Lo Bianco ◽  
Brunella Morandi ◽  
Mark Rieger
Keyword(s):  
Cell Division ◽  
Enzyme Activities ◽  
Developmental Stages ◽  
Sucrose Metabolism ◽  
Peach Fruit ◽  
Relative Growth ◽  
Neutral Invertase ◽  
Photosynthetic Product ◽  
Before And After ◽  
And Control

Along with sucrose, sorbitol represents the major photosynthetic product and the main form of translocated carbon in peach. The objective of the present study was to determine whether in peach fruit, sorbitol and sucrose enzyme activities are source-regulated, and more specifically modulated by sorbitol or sucrose availability. In two separate trials, peach fruit relative growth rate (RGR), enzyme activities, and carbohydrates were measured 1) at cell division stage before and after girdling of the shoot subtending the fruit; and 2) on 14 shoots with different leaf to fruit ratio (L:F) at cell division and cell expansion stages. Fruit RGR and sorbitol dehydrogenase (SDH) activity were significantly reduced by girdling, whereas sucrose synthase (SS), acid invertase (AI), and neutral invertase (NI) where equally active in girdled and control fruits on the fourth day after girdling. All major carbohydrates (sorbitol, sucrose, glucose, fructose and starch) were reduced on the fourth day after girdling. SDH activity was the only enzyme activity proportional to L:F in both fruit developmental stages. Peach fruit incubation in sorbitol for 24 hours also resulted in SDH activities higher than those of fruits incubated in buffer and similar to those of freshly extracted samples. Overall, our data provide some evidence for regulation of sorbitol metabolism, but not sucrose metabolism, by photoassimilate availability in peach fruit. In particular, sorbitol translocated to the fruit may function as a signal for modulating SDH activity.

scholarly journals Developmental series of gene expression clarifies maternal mRNA provisioning and maternal-to-zygotic transition in the reef-building coral Montipora capitata

2021 ◽  
Author(s):  
E Chille ◽  
E Strand ◽  
M Neder ◽  
V Schmidt ◽  
M Sherman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Division ◽  
Transcriptional Repression ◽  
Developmental Stages ◽  
Functional Enrichment ◽  
Peptide Transport ◽  
Essential Information ◽  
Montipora Capitata ◽  
Maternal Mrna ◽  
Maternal To Zygotic Transition

AbstractBackgroundMaternal mRNA provisioning of oocytes regulates early embryogenesis. Maternal transcripts are degraded as zygotic genome activation (ZGA) intensifies, a phenomenon known as the maternal-to-zygotic transition (MZT). Here, we examine gene expression over nine developmental stages in the Pacific rice coral, Montipora capitata, from eggs and embryos at 1, 4, 9, 14, 22, and 36 hours-post-fertilization (hpf), as well as swimming larvae (9d), and adult colonies.ResultsWeighted Gene Coexpression Network Analysis revealed four expression peaks, identifying the maternal complement, two waves of the MZT, and adult expression. Gene ontology enrichment revealed maternal mRNAs are dominated by cell division, methylation, biosynthesis, metabolism, and protein/RNA processing and transport functions. The first MZT wave occurs from ∼4-14 hpf and is enriched in terms related to biosynthesis, methylation, cell division, and transcription. In contrast, functional enrichment in the second MZT wave, or ZGA, from 22 hpf-9dpf, includes ion/peptide transport and cell signaling. Finally, adult expression is enriched for functions related to signaling, metabolism, and ion/peptide transport. Our proposed MZT timing is further supported by expression of enzymes involved in zygotic transcriptional repression (Kaiso) and activation (Sox2), which peak at 14 hpf and 22 hpf, respectively. Further, DNA methylation writing (DNMT3a) and removing enzymes (TET1) peak and remain stable past ∼4 hpf, indicating that methylome programming occurs before 4 hpf.ConclusionsOur high-resolution insight into the coral maternal mRNA and MZT provides essential information regarding setting the stage for, and the sensitivity of, developmental success and parental carryover effects under increasing environmental stress.

Developmental stages of delayed-greening leaves inferred from measurements of chlorophyll content and leaf growth

2009 ◽  
Vol 36 (7) ◽  
pp. 654 ◽  
Author(s):  
Andrzej Stefan Czech ◽  
Kazimierz Strzałka ◽  
Ulrich Schurr ◽  
Shizue Matsubara
Keyword(s):  
Cell Division ◽  
Cell Expansion ◽  
Developmental Stages ◽  
Leaf Growth ◽  
Co2 Assimilation ◽  
Leaf Expansion ◽  
Leaf Structure ◽  
Phase Iii ◽  
Clear Correlation ◽  
Delayed Greening

Chlorophyll (Chl) accumulation and leaf growth were analysed in delayed-greening leaves of Theobroma cacao (L.) to examine whether these parameters are correlated during leaf development and can be used as non-destructive indicators of leaf developmental stages. There was a clear correlation between Chl content and leaf relative growth rate (RGR) and between Chl content and percentage of full leaf expansion (%FLE) under different growth conditions. Five distinct developmental phases were defined according to the correlation between these parameters and corroborated by data from the analyses of leaf growth (epidermal cell size and specific leaf area) or photosynthetic properties (maximal PSII efficiency, CO2 assimilation and non-structural carbohydrate contents). The five phases were characterised by rapid leaf expansion by cell division (I), pronounced cell expansion (II), development of photosynthetic capacity concomitant with reinforcement of leaf structure (III), and maturation (IV and V). The transition from cell division to cell expansion happened uniformly across the leaf lamina between phase I and II; the sink-to-source transition was found between phase III and IV. These results demonstrate coordinated development of photosynthetic machinery and leaf structure in delayed-greening leaves and provide a simple and non-invasive method for estimation of leaf developmental stages in T. cacao.

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