Evaluation of Metaxylem Vessel Histogenesis and the Occurrence of Vessel Collapse during Early Development in Primary Roots of Zea mays ssp. mexicana: A Result of Premature Programmed Cell Death?

Root apical meristem histological organization in Zea mays has been carefully studied previously. Classical histology describes its system as having a “closed organization” and a development of xylem that conforms to predictable rules. Among the first cell types to begin differentiation are late-maturing metaxylem (LMX) vessels. As part of a larger study comparing domestic maize root development to a wild subspecies of Z. mays (teosinte), we encountered a metaxylem development abnormality in a small percentage of our specimens that begged further study, as it interrupted normal maturation of LMX. Primary root tips of young seedlings of Zea mays ssp. mexicana were fixed, embedded in appropriate resins, and sectioned for light and transmission electron microscopy. Longitudinal and serial transverse sections were analyzed using computer imaging to determine the position and timing of key xylem developmental events. We observed a severe abnormality of LMX development among 3.5% of the 227 mexicana seedlings we screened. All LMX vessel elements in these abnormal roots collapsed and probably became non-functional shortly after differentiation began. Cytoplasm and nucleoplasm in the abnormal LMX elements became condensed and subdivided into irregularly-shaped “macrovesicles” as their cell walls collapsed inward. We propose that these seedlings possibly suffered from a mutation that affected the timing of the programmed cell death (PCD) that is required to produce functional xylem vessels, such that autolysis of the cytoplasm was prematurely executed, i.e., prior to the development and lignification of secondary walls.

Download Full-text

Comparison of Promeristem Structure and Ontogeny of Procambium in Primary Roots of Zea mays ssp. Mexicana and Z. mays ‘Honey Bantam’ with Emphasis on Metaxylem Vessel Histogenesis

Plants ◽

10.3390/plants8060162 ◽

2019 ◽

Vol 8 (6) ◽

pp. 162 ◽

Cited By ~ 2

Author(s):

Susumu Saito ◽

Teruo Niki ◽

Daniel Gladish

Keyword(s):

Zea Mays ◽

Light Microscopy ◽

Root Development ◽

Apical Meristem ◽

Transverse Section ◽

Root Apical Meristem ◽

Root Tips ◽

Primary Roots ◽

Careful Comparison ◽

Number Of Cells

Classical histology describes the histological organization in Zea mays as having a “closed organization” that differs from Arabidopsis with the development of xylem conforming to predictable rules. We speculated that root apical meristem organization in a wild subspecies of Z. mays (a teosinte) would differ from a domestic sweetcorn cultivar (‘Honey Bantam’). Careful comparison could contribute to understanding how evolutionary processes and the domestication of maize have affected root development. Root tips of seedlings were prepared and sectioned for light microscopy. Most sections were treated with RNase before staining to increase contrast between the walls and cytoplasm. Longitudinal and serial transverse sections were analyzed using computer imaging to determine the position and timing of key xylem developmental events. Metaxylem development in mexicana teosinte differed from sweetcorn only in that the numbers of late-maturing metaxylem vessels in the latter are typically two-fold greater and the number of cells in the transverse section of procambium were greater in the latter, but parenchymatous cell sizes were not statistically different. Promeristems of both were nearly identical in size and organization, but did not operate quite as previously described. Mitotic activity was rare in the quiescent centers, but occasionally a synchronized pulse of mitoses was observed there. Our reinterpretation of histogen theory and procambium development should be useful for future detailed studies of regulation of development, and perhaps its evolution, in this species.

Download Full-text

Neuronal apoptosis: signal and cell diversity

Colombia Medica ◽

10.25100/cm.v40i1.634 ◽

1969 ◽

Vol 40 (1) ◽

pp. 124-133

Author(s):

Lina Vanessa Becerra ◽

Hernán José Pimienta

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Neuronal Response ◽

Neuronal Cell ◽

Cell Types ◽

Point Of View ◽

Trophic Factors ◽

Cell Diversity ◽

Apoptotic Pathways ◽

The Brain

Programmed cell death occurs as a physiological process during development. In the brain and spinal cord this event determines the number and location of the different cell types. In adulthood, programmed cell death or apoptosis is more restricted but it may play a major role in different acute and chronic pathological entities. However, in contrast to other tissues where apoptosis has been widely documented from a morphological point of view, in the central nervous system complete anatomical evidence of apoptosis is scanty. In spite of this there is consensus about the activation of different signal systems associated to programmed cell death. In the present article we attempt to summarize the main apoptotic pathways so far identified in nervous tissue. Considering that apoptotic pathways are multiple, the neuronal cell types are highly diverse and specialized and that neuronal response to injury and survival depends upon tissue context, (i.e., preservation of connectivity, glial integrity and cell matrix, blood supply and trophic factors availability) what is relevant for the apoptotic process in a sector of the brain may not be important in another.

Download Full-text

Hormonal control of programmed cell death/apoptosis

Acta Endocrinologica ◽

10.1530/eje.0.1380482 ◽

1998 ◽

pp. 482-491 ◽

Cited By ~ 75

Author(s):

W Kiess ◽

B Gallaher

Keyword(s):

Cell Death ◽

Mammary Gland ◽

Growth Factors ◽

Growth Factor ◽

Programmed Cell Death ◽

Cell Types ◽

Hormonal Control ◽

Endocrine Glands ◽

Survival Factors ◽

Endocrine Tissues

Apoptosis or programmed cell death is a physiological form of cell death that occurs in embryonic development and during involution of organs. It is characterized by distinct biochemical and morphological changes such as DNA fragmentation, plasma membrane blebbing and cell volume shrinkage. Many hormones, cytokines and growth factors are known to act as general and/or tissue-specific survival factors preventing the onset of apoptosis. In addition, many hormones and growth factors are also capable of inducing or facilitating programmed cell death under physiological or pathological conditions, or both. Steroid hormones are potent regulators of apoptosis in steroid-dependent cell types and tissues such as the mammary gland, the prostate, the ovary and the testis. Growth factors such as epidermal growth factor, nerve growth factor, platelet-derived growth factor (PDGF) and insulin-like growth factor-I act as survival factors and inhibit apoptosis in a number of cell types such as haematopoietic cells, preovulatory follicles, the mammary gland, phaeochromocytoma cells and neurones. Conversely, apoptosis modulates the functioning and the functional integrity of many endocrine glands and of many cells that are capable of synthesizing and secreting hormones. In addition, exaggeration of the primarily natural process of apoptosis has a key role in the pathogenesis of diseases involving endocrine tissues. Most importantly, in autoimmune diseases such as autoimmune thyroid disease and type 1 diabetes mellitus, new data suggest that the immune system itself may not carry the final act of organ injury: rather, the target cells (i.e. thyrocytes and beta cells of the islets) commit suicide through apoptosis. The understanding of how hormones influence programmed cell death and, conversely, of how apoptosis affects endocrine glands, is central to further design strategies to prevent and treat diseases that affect endocrine tissues. This short review summarizes the available evidence showing where and how hormones control apoptosis and where and how programmed cell death exerts modulating effects upon hormonally active tissues.

Download Full-text

Nitric oxide suppresses aluminum-induced programmed cell death in peanut ( Arachis hypoganea L.) root tips by improving mitochondrial physiological properties

Nitric Oxide ◽

10.1016/j.niox.2018.01.003 ◽

2018 ◽

Vol 74 ◽

pp. 47-55 ◽

Cited By ~ 11

Author(s):

Huyi He ◽

Wenjing Huang ◽

Thet Lwin Oo ◽

Minghua Gu ◽

Jie Zhan ◽

...

Keyword(s):

Nitric Oxide ◽

Cell Death ◽

Programmed Cell Death ◽

Root Tips ◽

Physiological Properties

Download Full-text

Role of Ced-3/ICE-family proteases in staurosporine-induced programmed cell death.

The Journal of Cell Biology ◽

10.1083/jcb.133.5.1041 ◽

1996 ◽

Vol 133 (5) ◽

pp. 1041-1051 ◽

Cited By ~ 270

Author(s):

M D Jacobsen ◽

M Weil ◽

M C Raff

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Mammalian Cell ◽

Mammalian Cells ◽

Apoptotic Cell ◽

Interleukin 1 ◽

Cell Types ◽

Cysteine Proteases ◽

A Cell ◽

Bona Fide

In the accompanying paper by Weil et al. (1996) we show that staurosporine (STS), in the presence of cycloheximide (CHX) to inhibit protein synthesis, induces apoptotic cell death in a large variety of nucleated mammalian cell types, suggesting that all nucleated mammalian cells constitutively express all of the proteins required to undergo programmed cell death (PCD). The reliability of that conclusion depends on the evidence that STS-induced, and (STS + CHS)-induced, cell deaths are bona fide examples of PCD. There is rapidly accumulating evidence that some members of the Ced-3/Interleukin-1 beta converting enzyme (ICE) family of cysteine proteases are part of the basic machinery of PCD. Here we show that Z-Val-Ala-Asp-fluoromethylketone (zVAD-fmk), a cell-permeable, irreversible, tripeptide inhibitor of some of these proteases, suppresses STS-induced and (STS + CHX)-induced cell death in a wide variety of mammalian cell types, including anucleate cytoplasts, providing strong evidence that these are all bona fide examples of PCD. We show that the Ced-3/ICE family member CPP32 becomes activated in STS-induced PCD, and that Bcl-2 inhibits this activation. Most important, we show that, in some cells at least, one or more CPP32-family members, but not ICE itself, is required for STS-induced PCD. Finally, we show that zVAD-fmk suppresses PCD in the interdigital webs in developing mouse paws and blocks the removal of web tissue during digit development, suggesting that this inhibition will be a useful tool for investigating the roles of PCD in various developmental processes.

Download Full-text

RNA-Seq Transcriptome Analysis of Rice Primary Roots Reveals the Role of Flavonoids in Regulating the Rice Primary Root Growth

Genes ◽

10.3390/genes10030213 ◽

2019 ◽

Vol 10 (3) ◽

pp. 213

Author(s):

Yu Xu ◽

Junjie Zou ◽

Hongyan Zheng ◽

Miaoyun Xu ◽

Xuefeng Zong ◽

...

Keyword(s):

Cell Wall ◽

Root Growth ◽

Primary Root ◽

Glutathione Metabolism ◽

Auxin Signaling ◽

Antioxidant Enzyme Activities ◽

Rna Seq ◽

Root Tips ◽

Primary Roots ◽

Quercetin Treatment

Flavonoids play important roles in root development and in its tropic responses, whereas the flavonoids-mediated changes of the global transcription levels during root growth remain unclear. Here, the global transcription changes in quercetin-treated rice primary roots were analyzed. Quercetin treatment significantly induced the inhibition of root growth and the reduction of H2O2 and O2− levels. In addition, the RNA-seq analysis revealed that there are 1243 differentially expressed genes (DEGs) identified in quercetin-treated roots, including 1032 up-regulated and 211 down-regulated genes. A gene ontology (GO) enrichment analysis showed that the enriched GO terms are mainly associated with the cell wall organization, response to oxidative stress, and response to hormone stimulus. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway analysis showed that the enriched DEGs are involved in phenylpropanoid biosynthesis, glutathione metabolism, and plant hormone signal transduction. Moreover, the quercetin treatment led to an increase of the antioxidant enzyme activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) in rice roots. Also, the quercetin treatment altered the DR5:GUS expression pattern in the root tips. All of these data indicated that the flavonoids-mediated transcription changes of genes are related to the genes involved in cell wall remodeling, redox homeostasis, and auxin signaling, leading to a reduced cell division in the meristem zone and cell elongation in the elongation zone of roots.

Download Full-text

Programmed Cell Death: New Role in Trimming the Root Tips

Current Biology ◽

10.1016/j.cub.2014.03.055 ◽

2014 ◽

Vol 24 (9) ◽

pp. R374-R376 ◽

Cited By ~ 2

Author(s):

Shri Ram Yadav ◽

Ykä Helariutta

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Root Tips

Download Full-text

Early redistribution of plasma membrane phosphatidylserine is a general feature of apoptosis regardless of the initiating stimulus: inhibition by overexpression of Bcl-2 and Abl.

Journal of Experimental Medicine ◽

10.1084/jem.182.5.1545 ◽

1995 ◽

Vol 182 (5) ◽

pp. 1545-1556 ◽

Cited By ~ 1934

Author(s):

S J Martin ◽

C P Reutelingsperger ◽

A J McGahon ◽

J A Rader ◽

R C van Schie ◽

...

Keyword(s):

Cell Death ◽

Plasma Membrane ◽

Programmed Cell Death ◽

General Feature ◽

Annexin V ◽

Cell Types ◽

Morphological Features ◽

Critical Event ◽

Specific Probe ◽

Macromolecular Synthesis

A critical event during programmed cell death (PCD) appears to be the acquisition of plasma membrane (PM) changes that allows phagocytes to recognize and engulf these cells before they rupture. The majority of PCD seen in higher organisms exhibits strikingly similar morphological features, and this form of PCD has been termed apoptosis. The nature of the PM changes that occur on apoptotic cells remains poorly defined. In this study, we have used a phosphatidylserine (PS)-binding protein (annexin V) as a specific probe to detect redistribution of this phospholipid, which is normally confined to the inner PM leaflet, during apoptosis. Here we show that PS externalization is an early and widespread event during apoptosis of a variety of murine and human cell types, regardless of the initiating stimulus, and precedes several other events normally associated with this mode of cell death. We also report that, under conditions in which the morphological features of apoptosis were prevented (macromolecular synthesis inhibition, overexpression of Bcl-2 or Abl), the appearance of PS on the external leaflet of the PM was similarly prevented. These data are compatible with the notion that activation of an inside-outside PS translocase is an early and widespread event during apoptosis.

Download Full-text

Impact of soil compaction heterogeneity and moisture on maize (Zea mays L.) root and shoot development

Plant Soil and Environment ◽

10.17221/429-pse ◽

2008 ◽

Vol 54 (No. 12) ◽

pp. 509-519 ◽

Cited By ~ 8

Author(s):

B. Konôpka ◽

L. Pagès ◽

C. Doussan

Keyword(s):

Zea Mays ◽

Soil Moisture ◽

Soil Compaction ◽

Statistical Tests ◽

Lateral Roots ◽

Primary Root ◽

Leaf Biomass ◽

Fine Soil ◽

Primary Roots ◽

Primary And Lateral Roots

Soil compaction heterogeneity and water content are supposed to be decisive factors influencing plant growth. Our experiment focused on simulation of two soil moisture levels (0.16 and 0.19 g/g) plus two levels of clod proportion (30 and 60% volume) and their effects on root and leaf variables of maize (Zea mays L.). We studied number of primary and lateral roots as well as primary root length at the particular soil depths. Statistical tests showed that the decrease rate of the number of roots versus depth was significantly affected by the two studied factors (P < 0.01). Soil moisture and clod occurrence, interactively, affected leaf biomass (P = 0.02). Presence of clods modified root morphological features. Particularly, the diameter of primary roots in the clods was significantly higher than of those grown in fine soil (P < 0.01). For primary roots, which penetrated clods, branching density decreased considerably for the root segments located just after the clods (P = 0.01). Regarding their avoidance to clods and tortuosity, large differences were found between primary roots grown in the contrasting soil environments.

Download Full-text