Early Periderm Ontogeny in Fraxinuspennsylvanica, Ailanthusaltissima, Robiniapseudoacacia, and Pinusresinosa, Seedlings

1972 ◽  
Vol 2 (2) ◽  
pp. 135-143 ◽  
Author(s):  
G. A. Borger ◽  
T. T. Kozlowski
Keyword(s):  
Cell Layer ◽  
Cortical Cell ◽  
Cortical Cells ◽  
Mother Cells

The subepidermal cell layer was the site of origin of the first periderm in the hypocotyl and internodes of Fraxinuspennsylvanica and Ailanthusaltissima. In the hypocotyl of Robiniapsendoacacia, the first periderm arose in cortical cells near the phloem; in the internodes it originated in the subepidermal, second, or third cortical cell layer. The outermost cell layer of the pericycle gave rise to the first periderm in the hypocotyl of Pinusresinosa. In all four species, periderm appeared first near the base of the hypocotyl and developed acropetally. In A. altissima and R. pseudoaeacia, phellem mother cells were cut off by the phellogen. These subsequently divided to produce phellem cells. In F. pennsylvanica and P. resinosa, phellem cells were produced directly from the phellogen.

Computing with Self-Excitatory Cliques: A Model and an Application to Hyperacuity-Scale Computation in Visual Cortex

1999 ◽  
Vol 11 (1) ◽  
pp. 21-66 ◽  
Author(s):  
Douglas A. Miller ◽  
Steven W. Zucker
Keyword(s):  
Visual Processing ◽  
Network Architecture ◽  
Early Stage ◽  
Cortical Cell ◽  
Pyramidal Cells ◽  
Direct Calculation ◽  
Formal Theory ◽  
Cortical Cells ◽  
Cell Counts ◽  
Spatiotemporal Response

We present a model of visual computation based on tightly inter-connected cliques of pyramidal cells. It leads to a formal theory of cell assemblies, a specific relationship between correlated firing patterns and abstract functionality, and a direct calculation relating estimates of cortical cell counts to orientation hyperacuity. Our network architecture is unique in that (1) it supports a mode of computation that is both reliable and efficent; (2) the current-spike relations are modeled as an analog dynamical system in which the requisite computations can take place on the time scale required for an early stage of visual processing; and (3) the dynamics are triggered by the spatiotemporal response of cortical cells. This final point could explain why moving stimuli improve vernier sensitivity.

NHE3 activity and trafficking depend on the state of actin organization in proximal tubule

2001 ◽  
Vol 280 (2) ◽  
pp. F283-F290 ◽  
Author(s):  
C. Chalumeau ◽  
D. Du Cheyron ◽  
N. Defontaine ◽  
O. Kellermann ◽  
M. Paillard ◽  
...  
Keyword(s):  
Proximal Tubule ◽  
Cortical Cell ◽  
Membrane Vesicles ◽  
Cytochalasin D ◽  
The State ◽  
Protein Abundance ◽  
Transport Activity ◽  
Cortical Cells ◽  
Actin Organization ◽  
Luminal Membrane

The present study was addressed to define the contribution of cytoskeleton elements in the kidney proximal tubule Na+/H+ exchanger 3 (NHE3) activity under basal conditions. We used luminal membrane vesicles (LMV) isolated from suspensions of rat cortical tubules pretreated with either colchicine (Colch) or cytochalasin D (Cyto D). Colch pretreatment of suspensions (200 μM for 60 min) moderately decreased LMV NHE3 activity. Cyto D pretreatment (1 μM for 60 min) elicited an increase in LMV NHE3 transport activity but did not increase Na-glucose cotransport activity. Cyto D pretreatment of suspensions did not change the apparent affinity of NHE3 for internal H+. In contrast, after Cyto D pretreatment of the suspensions, NHE3 protein abundance was increased in LMV and remained unchanged in cortical cell homogenates. The effect of Cyto D on NHE3 was further assessed with cultures of murine cortical cells. The amount of surface biotinylated NHE3 increased on Cyto D treatment, whereas NHE3 protein abundance was unchanged in cell homogenates. In conclusion, under basal conditions NHE3 activity depends on the state of actin organization possibly involved in trafficking processes between luminal membrane and intracellular compartment.

A shared gene drives lateral root development and root nodule symbiosis pathways in Lotus

Science ◽  
2019 ◽  
Vol 366 (6468) ◽  
pp. 1021-1023 ◽  
Author(s):  
Takashi Soyano ◽  
Yoshikazu Shimoda ◽  
Masayoshi Kawaguchi ◽  
Makoto Hayashi
Keyword(s):  
Root Development ◽  
Lateral Root ◽  
Root Nodule ◽  
Root Nodules ◽  
Lotus Japonicus ◽  
Cortical Cell ◽  
Cortical Cells ◽  
Lateral Root Development ◽  
Lateral Organ ◽  
Nodule Symbiosis

Legumes develop root nodules in symbiosis with nitrogen-fixing rhizobial bacteria. Rhizobia evoke cell division of differentiated cortical cells into root nodule primordia for accommodating bacterial symbionts. In this study, we show that NODULE INCEPTION (NIN), a transcription factor in Lotus japonicus that is essential for initiating cortical cell divisions during nodulation, regulates the gene ASYMMETRIC LEAVES 2-LIKE18/LATERAL ORGAN BOUNDARIES DOMAIN16a (ASL18/LBD16a). Orthologs of ASL18/LBD16a in nonlegume plants are required for lateral root development. Coexpression of ASL18a and the CCAAT box–binding protein Nuclear Factor-Y (NF-Y) subunits, which are also directly targeted by NIN, partially suppressed the nodulation-defective phenotype of L. japonicusdaphne mutants, in which cortical expression of NIN was attenuated. Our results demonstrate that ASL18a and NF-Y together regulate nodule organogenesis. Thus, a lateral root developmental pathway is incorporated downstream of NIN to drive nodule symbiosis.

scholarly journals Domain-specific and cell type-specific localization of two types of cell wall matrix polysaccharides in the clover root tip.

1992 ◽  
Vol 118 (2) ◽  
pp. 467-479 ◽  
Author(s):  
M A Lynch ◽  
L A Staehelin
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cellular Differentiation ◽  
Cortical Cell ◽  
Middle Lamella ◽  
Root Cap ◽  
Root Tip ◽  
Cortical Cells ◽  
Peripheral Cell ◽  
Clover Root

Using immunocytochemical techniques and antibodies that specifically recognize xyloglucan (anti-XG), polygalacturonic acid/rhamnogalacturonan I (anti-PGA/RG-I), and methylesterified pectins (JIM 7), we have shown that these polysaccharides are differentially synthesized and localized during cell development and differentiation in the clover root tip. In cortical cells XG epitopes are present at a threefold greater density in the newly formed cross walls than in the older longitudinal walls, and PGA/RG-I epitopes are detected solely in the expanded middle lamella of cortical cell corners, even after pretreatment of sections with pectinmethylesterase to uncover masked epitopes. These results suggest that in cortical cells XG and PGA/RG-I are differentially localized not only to particular wall domains, but also to particular cell walls. In contrast to their nonoverlapping distribution in cortical cells, XG epitopes and PGA/RG-I epitopes largely colocalize in the epidermal cell walls. The results also demonstrate that the middle lamella of the longitudinal walls shared by epidermal cells and by epidermal and cortical cells constitutes a barrier to the diffusion of cell wall and mucilage molecules. Synthesis of XG and PGA/RG-I epitope-containing polysaccharides also varies during cellular differentiation in the root cap. The differentiation of gravitropic columella cells into mucilage-secreting peripheral cells is marked by a dramatic increase in the synthesis and secretion of molecules containing XG and PGA/RG-I epitopes. In contrast, JIM 7 epitopes are present at abundant levels in columella cell walls, but are not detectable in peripheral cell walls or in secreted mucilage. There were also changes in the cisternal labeling of the Golgi stacks during cellular differentiation in the root tip. Whereas PGA/RG-I epitopes are detected primarily in cis- and medial Golgi cisternae in cortical cells (Moore, P. J., K. M. M. Swords, M. A. Lynch, and L. A. Staehelin. 1991. J. Cell Biol. 112:589-602), they are localized predominantly in the trans-Golgi cisternae and the trans-Golgi network in epidermal and peripheral root cap cells. These observations suggest that during cellular differentiation the plant Golgi apparatus can be both structurally and functionally reorganized.

Excitation and inhibition in orientation selectivity of cat visual cortex neurons revealed by whole-cell recordings in vivo

1993 ◽  
Vol 10 (6) ◽  
pp. 1151-1155 ◽  
Author(s):  
M. Volgushev ◽  
Xing Pei ◽  
T. R. Vidyasagar ◽  
O. D. Creutzfeldt
Keyword(s):  
Striate Cortex ◽  
Cortical Cell ◽  
Orientation Selectivity ◽  
Cortical Cells ◽  
Whole Cell ◽  
Degree Of Orientation ◽  
Visual Cortex Neurons ◽  
High Degree ◽  
Whole Cell Recordings

AbstractOne striking transformation in response properties that occurs in the geniculo-cortical pathway is the appearance of a high degree of orientation selectivity in the cortex. This property may be conceived as arising purely from the excitatory inputs to the cell, as being structured largely by the inhibition a cortical cell receives or could be due to a combination of the two. We have studied the contributions of excitatory and inhibitory inputs to cortical cells' orientation selectivity by analyzing the postsynaptic potentials evoked in cat striate neurones by flashing stimuli of different orientations. We made these recordings using the in vivo whole-cell technique (Xing Pei et al., 1991), which provides more stable and reliable results than classical intracellular recording methods. Our results show that the cat striate cortex exhibits a variety of mechanisms to achieve orientation selectivity. Orientation selectivity of a particular cell can be created by excitatory, by inhibitory, or by a combination of both mechanisms.

scholarly journals Microglia induce neurogenesis by stimulating PI3K/AKT intracellular signaling in vitro

2019 ◽  
Author(s):  
Kristi Lorenzen ◽  
Nicholas W. Mathy ◽  
Erin R. Whiteford ◽  
Alex Eischeid ◽  
Jing Chen ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Viability ◽  
Intracellular Signaling ◽  
Cortical Cell ◽  
Model System ◽  
Microglial Cells ◽  
Cortical Cells ◽  
Akt Phosphorylation ◽  
Cortical Neurogenesis

Abstract Background: Emerging evidence suggests that microglia can support neuronal survival, synapse development, and neurogenesis in classic neurogenic niches. Little is known about the ability of microglia to regulate the cortical environment and stimulate cortical neurogenesis outside classic neurogenic niches. We used an in vitro co-culture model system to investigate the hypothesis that microglia respond to soluble signals from cortical cells, particularly following injury, to alter the cortical environment and promote cortical cell proliferation, differentiation, and maintain cortical cell survival via activation of specific cortical intracellular signaling pathways. Results: Analyses of cell proliferation, apoptosis, protein expression, and intracellular signaling pathway activation were performed on uninjured and injured cortical cells in co-culture with EOC2 microglia. EOC2 microglia in co-culture enhanced cortical cell viability and proliferation of uninjured and injured cortical cells. Co-culture of injured cortical cells with EOC2 microglial cells significantly reduced cortical cell apoptosis. Microglial co-culture significantly increased Nestin+ and a-internexin+ cells within and outside of the injury site. NeuN+ cells increased in injured cortical cultures with microglia. Multiplex ELISA assays showed decreased levels of inflammatory cytokines in conditioned media from injured cortical cell and microglial co-culture. RTPCR analysis of microglial mRNA was performed. EOC2 microglial co-culture environment increased AKT phosphorylation in cortical cells particularly following injury. Inhibition of AKT phosphorylation in cortical cells blocked the microglial-enhanced cortical cell viability and expression of neurogenic markers in vitro. Conclusion: The in vitro model system presented here allows for assessment of the effect of microglial-derived soluble signals, independent of cell-cell contact, on cortical cell viability, proliferation, and stages of differentiation during homeostasis or following injury. These data suggest that microglia downregulate inflammatory cytokine production following activation by acute cortical injury to enhance proliferation of new cells capable of neurogenesis. Inhibition of AKT signaling in cortical cells blocks the enhanced proliferation and expression of neurogenic markers in cortical cells. Increasing our understanding of the mechanisms that drive cortical neurogenesis stimulated by microglial cells during homeostasis and following injury will provide insight into the potential mechanisms of neuroprotective role of immune activity in the central nervous system (CNS).

scholarly journals Cell Proliferation and Cortical Cell Production in Relation to Wool Growth

1979 ◽  
Vol 32 (3) ◽  
pp. 317 ◽  
Author(s):  
Patricia A Wilson ◽  
BF Short
Keyword(s):  
Cell Proliferation ◽  
Nutrient Intake ◽  
Cortical Cell ◽  
Cortical Cells ◽  
Wool Growth ◽  
Wide Range ◽  
High Level ◽  
Relationship Of ◽  
The Relationship ◽  
Germinal Cells

The relationship of wool growth to cell proliferation in the follicle bulb and to the subsequent migration and growth of the fibre cortical cells was investigated in 10 Peppin Merino sheep. These sheep had been maintained on a low, medium or high level of nutrient intake to ensure a wide range in wool growth. The number and mitotic activity of the germinal cells in the follicle bulb were determined after administration of colchicine. Cortical cell size was measured following isolation of the fibre cells by acid-treatment of wool.

scholarly journals Stiffness of Human Hair Correlates with the Fractions of Cortical Cell Types

Cosmetics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 24 ◽  
Author(s):  
Yusuke Ezawa ◽  
Shinobu Nagase ◽  
Akira Mamada ◽  
Shigeto Inoue ◽  
Kenzo Koike ◽  
...  
Keyword(s):  
Human Hair ◽  
Fluorescent Dyes ◽  
Cortical Cell ◽  
Cell Types ◽  
Cortical Cells ◽  
Force Microscopy ◽  
Bending Modulus ◽  
Hair Samples ◽  
Fluorescence Light ◽  
The Difference

(1) Background: The objective of this work was to elucidate the hair microstructure which correlates with the stiffness of human hair fibers. (2) Methods: Bending moduli of hair fibers were evaluated for the hair samples from 156 Japanese female subjects. Hair transverse sections were dual-stained with fluorescent dyes which can stain para- and ortho-like cortical cells separately, and observed under a fluorescence light microscope. Atomic force microscopy nanoindentation measurements were performed to examine the modulus inside macrofibrils. (3) Results: The difference in bending moduli between the maximum and the minimum values was more than double. The hair of high bending modulus was rich in para-like cortical cells and the bending modulus significantly correlated with the fraction of para-like cortical cells to the whole cortex. On the other hand, the elastic moduli inside macrofibrils were almost same for the para- and ortho-like cortical cells. (4) Conclusions: Hair bending modulus depends on the fractions of the constitutional cortical cell types. The contribution of the intermacrofibrillar materials, which differed in their morphologies and amounts of para- and ortho-like cortical cells, is plausible as a cause of the difference in the modulus of the cortical cell types.

Simulation of Cortex Visual Cells for Texture Segmentation: Foveal and Parafoveal Projections

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 120-120
Author(s):  
P M Palagi ◽  
A Guérin-Dugué
Keyword(s):  
Recognition Rate ◽  
Cortical Cell ◽  
Spatial Vision ◽  
Texture Segmentation ◽  
Cortical Cells ◽  
Frequency Bands ◽  
Visual Cells ◽  
Neurophysiological Data ◽  
Band Pass ◽  
Visual Cortical

The objective of this work is to simulate visual cortical cells, their sensitivities to frequencies and orientations, and their part in texture segmentation. The simulation of these cells is realised through band-pass, oriented filters (Gabor filters), and multiresolution image decomposition. By this means, the filter sensitivities represent cell sensitivities to preferred orientations according to their frequency and orientation bandwidths, and multiresolution represents the different band frequencies. For texture analysis and segmentation, overlaying of band-pass filters is necessary to completely cover the Fourier domain. A continuous sensitivity to frequency and orientation is achieved by the filters overlapping and consequently by their interpolation. We used here four octave frequency bands from 1 to 16 cycles deg−1 and six orientations per band. The results obtained for texture segmentation with these parameters are very promising (up to 97% recognition rate) [Guérin-Dugué and Palagi, 1994 Neural Processing Letters1(1) 25 – 29]. The images analysed cover a multitude of different domains such as psychophysical tests and natural textures of different roughness. In order to create a cortical cell representation closer to neurophysiological data, and to improve texture segmentation results, we represent cell sensitivities by their foveal and parafoveal projections [R L DeValois, K K DeValois, 1988 Spatial Vision (Oxford: Oxford Science Publications)]. Cells receiving projections from the foveal zone are modeled by five octave frequency bands (from 0.5 to 16 cycles deg−1) and six orientations. Cells receiving projections from the parafoveal zone have the same sensitivities but are modeled by four octave frequency bands (from 0.5 to 8 cycles deg−1). By using these two different resolutions, preliminary tests have shown the capability of detecting textured regions by the parafoveal projection and localisation of boundaries by the foveal projection.

Corticomotoneuronal postspike effects in averages of unrectified EMG activity

1989 ◽  
Vol 62 (5) ◽  
pp. 1127-1139 ◽  
Author(s):  
G. W. Botteron ◽  
P. D. Cheney
Keyword(s):  
Muscle Activity ◽  
Effective Means ◽  
Cortical Cell ◽  
Emg Activity ◽  
Cortical Cells ◽  
Cell Discharge ◽  
Full Wave ◽  
Spike Triggered Averaging ◽  
Cell Target ◽  
Activity Loss

1. Spike-triggered averaging (SpTA) of rectified electromyograms (EMGs) in awake monkeys is recognized as an effective means of establishing causal relations between cortical/cell discharge and muscle activity. The appearance of postspike facilitation (PSF) in averages of rectified EMG activity is interpreted as evidence of an underlying excitatory synaptic linkage between the trigger cell and motoneurons. Cells producing PSF are referred to as corticomotoneuronal (CM) cells. Similarly, postspike suppression (PSS) is interpreted as evidence of underlying inhibitory synaptic linkages. Studies to date have focused almost exclusively on averages of full-wave rectified EMG activity. Because the potential utility of SpTA of unrectified EMG activity has not been systematically examined, we compared postspike effects in SpTAs of rectified and unrectified EMGs for 44 cortical cells yielding 293 cell-target muscle pairs (CMPs). 2. Clear PSF was found in 110 of 293 averages of rectified EMG activity from 28 known CM cells. Forty-nine of these 110 CMPs (45%) also showed clear postspike effects (PSE) in the corresponding averages of unrectified EMGs activity. Loss of effects in averages of unrectified EMGs can be attributed to cancellation of the negative and positive phases of motor unit potentials. Mean onset latencies were similar for effects in rectified and unrectified EMGs [6.9 +/- 1.8 (SD) ms vs. 6.6 +/- 1.2 (SD) ms]. Overall, the magnitudes of effects measured as peak-to-noise ratios were also similar for effects in the two groups (8.8 vs. 8.7). The 61 CMPs that showed clear PSF in rectified EMGs but no effects in corresponding unrectified EMGs had, as a group, longer and more dispersed onset latencies and were weaker in magnitude than those that showed effects in both rectified and unrectified EMGs. Moreover, the occurrence of clear effects in averages of unrectified EMGs was correlated with the strength of PSF (75% of strong but only 29% of weak PSFs showed clear PSEs in averages of unrectified EMG activity). 3. Clear PSS was observed in 24 (8%) averages of rectified EMGs derived from nine cells. Remarkably, clear PSEs were found in 12 of the corresponding averages of unrectified EMG activity.(ABSTRACT TRUNCATED AT 400 WORDS)

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