Cytodifferentiation during the development of friable embryogenic callus of maize (Zea mays)

1991 ◽  
Vol 69 (1) ◽  
pp. 26-33 ◽  
Author(s):  
P. F. Fransz ◽  
J. H. N. Schel
Keyword(s):  
Zea Mays ◽  
Light Microscopy ◽  
Developmental Stages ◽  
Central Nucleus ◽  
Striking Difference ◽  
Vascular Bundles ◽  
Embryogenic Cells ◽  
Friable Callus ◽  
Vascular Elements

Immature embryos of Zea mays L. were cultured on N6 medium to obtain embryogenie callus. Cultured tissue fragments with various developmental stages of friable callus were sampled and prepared for light microscopy and transmission electron microscopy. Pieces of compact callus were also prepared for light microscopy to compare the structural organization of both callus types. Friable callus develops from a thin layer of abaxial scutellum cells, including the epidermis. During further development the callus cells dissociate, owing to the breakdown of the middle lamellae, while older vacuolated cells degenerate. This results into long cell aggregates separated by large intercellular spaces, giving the callus its friable appearance. The microscopical sections showed a striking difference between friable and compact callus. Vascular elements were not found in the friable callus. On the contrary, vascular bundles were prominent in compact callus. Friable callus is therefore correlated with a less differentiated state than compact callus. The embryogenic potential of friable callus is situated in embryogenic units. These are aggregates of small isodiametric cells containing a central nucleus, an electron-dense cytoplasm, and many organelles. Proliferation was only observed in these cells, which are therefore presumed to generate new embryogenic units, somatic embryos, and vacuolated callus cells. The results further indicate that discrete masses of embryogenic cells, possibly early embryoids, have a unicellular origin. Key words: in vitro culture, callus, somatic embryogenesis, ultrastructure, Zea mays.

Etude ultrastructurale des processus de biodégradation. I. Pourriture blanche des feuilles de Hêtre (Fagus sylvatica L.)

1978 ◽  
Vol 24 (6) ◽  
pp. 725-733 ◽  
Author(s):  
O. Reisinger ◽  
F. Toutain ◽  
F. Mangenot ◽  
Marie-France Arnould
Keyword(s):  
Cell Walls ◽  
Developmental Stages ◽  
Lethal Factor ◽  
White Rot ◽  
Apical Region ◽  
Vascular Bundles ◽  
Plant Cell Walls ◽  
Electron Microscopic ◽  
Fagus Sylvatica L

An electron microscopic study of beech leaf white rot shows a certain number of characteristic developmental stages which are identical whether the material is from in vitro experimentation or from natural incubation. Endowed with a cellulolytic property seemingly localized in the apical region only, hyphae of the white rot agent only traverse the plant cell walls. Subsequently, hyphae penetrate condensed protoplasmic residues and make them progressively transparent to electrons. During this discoloring process, a lethal factor of as yet unknown nature appears, affecting other microorganisms already present in the leaves. Phloem and xylem vascular bundles do not present notable ultrastructural modifications. Therefore, leaf discoloration is not due to an alteration of the xylem constituents but to changes having occurred in the condensed cytoplasmic residues of the dead tissues.

An ultrastructural study on the early development of Zea mays somatic embryos

1991 ◽  
Vol 69 (4) ◽  
pp. 858-865 ◽  
Author(s):  
P. F. Fransz ◽  
J. H. N. Schel
Keyword(s):  
Zea Mays ◽  
Early Development ◽  
Embryogenic Callus ◽  
Somatic Embryos ◽  
Zea Mays L ◽  
Light And Electron Microscopy ◽  
Apical Region ◽  
Basal Region ◽  
Embryogenic Cells

Friable embryogenic callus, obtained from immature embryos of Zea mays L., was cultured on N6 medium supplemented with 1 mg/L 2,4-dichlorophenoxyacetic acid, 6 mM proline, and 2% sucrose. Cultured tissue fragments containing several globular embryoids were excised and examined by light and electron microscopy to follow the early development of maize embryoids. The somatic embryos consist of an apical region and a suspensor region. Cells of the apical region are small, cytoplasm rich, and mitotically active. They contain much starch and numerous bundles of microtubules. Suspensor cells are larger and more vacuolated. A high metabolic activity in both cell types is indicated by the presence of many organelles, coated vesicles, and multivesicular bodies. Transition units appear to form intermediate stages between the embryogenic callus cells and the somatic embryo. A transition unit consists of a group of embryogenic cells and shows an apical and a basal region. The unit has many intercellular spaces, and within the cells areas with organelle-free cytosol are frequently observed. Key words: somatic embryogenesis, in vitro culture, ultrastructure, Zea mays L.

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

Use of light microscopy in the qualitative and quantitative study of liquid crystalline order

1992 ◽  
Vol 50 (1) ◽  
pp. 264-265
Author(s):  
Christopher Viney
Keyword(s):  
Light Microscopy ◽  
Liquid Crystalline ◽  
Structural Characteristics ◽  
Molecular Order ◽  
Liquid Crystalline Phases ◽  
Convenient Technique ◽  
Liquid Crystalline Materials ◽  
Transparent Windows

Light microscopy is a convenient technique for characterizing molecular order in fluid liquid crystalline materials. Microstructures can usually be observed under the actual conditions that promote the formation of liquid crystalline phases, whether or not a solvent is required, and at temperatures that can range from the boiling point of nitrogen to 600°C. It is relatively easy to produce specimens that are sufficiently thin and flat, simply by confining a droplet between glass cover slides. Specimens do not need to be conducting, and they do not have to be maintained in a vacuum. Drybox or other controlled environmental conditions can be maintained in a sealed chamber equipped with transparent windows; some heating/ freezing stages can be used for this purpose. It is relatively easy to construct a modified stage so that the generation and relaxation of global molecular order can be observed while specimens are being sheared, simulating flow conditions that exist during processing. Also, light only rarely affects the chemical composition or molecular weight distribution of the sample. Because little or no processing is required after collecting the sample, one can be confident that biologically derived materials will reveal many of their in vivo structural characteristics, even though microscopy is performed in vitro.

Development of an in vitro Model for the Study of the Response of Equine Tendon Fibroblasts to Injury and Medication

1997 ◽  
Vol 10 (01) ◽  
pp. 6-11 ◽  
Author(s):  
R. F. Rosenbusch ◽  
L. C. Booth ◽  
L. A. Dahlgren
Keyword(s):  
Electron Microscopy ◽  
Extracellular Matrix ◽  
Light Microscopy ◽  
Light And Electron Microscopy ◽  
Tendon Healing ◽  
Matrix Proteins ◽  
Isolated Cells ◽  
Superficial Digital Flexor Tendon ◽  
Vitro Model

SummaryEquine tendon fibroblasts were isolated from explants of superficial digital flexor tendon, subcultured and maintained in monolayers. The cells were characterized by light microscopy, electron microscopy and radiolabel studies for proteoglycan production. Two predominant cell morphologies were identified. The cells dedifferentiated toward a more spindle shape with repeated subcultures. Equine tendon fibroblasts were successfully cryopreserved and subsequently subcultured. The ability to produce proteoglycan was preserved.The isolated cells were identified as fibroblasts, based on their characteristic shape by light microscopy and ultrastructure and the active production of extracellular matrix proteins. Abundant rough endoplasmic reticulum and the production of extracellular matrix products demonstrated active protein production and export. Proteoglycans were measurable via liquid scintillation counting in both the cell-associated fraction and free in the supernatant. This model is currently being utilized to study the effects of polysulfated glycosaminoglycan on tendon healing. Future uses include studying the effects of other pharmaceuticals, such as hyaluronic acid, on tendon healing.A model was developed for in vitro investigations into tendon healing. Fibroblasts were isolated from equine superficial digital flexor tendons and maintained in monolayer culture. The tenocytes were characterized via light and electron microscopy. Proteoglycan production was measured, using radio-label techniques. The fibroblasts were cryopreserved and subsequently subcultured. The cells maintained their capacity for proteoglycan production, following repeated subculturing and cryopreservation.

In vitro growth analysis of zea mays l. Using silver nanoparticles

2017 ◽  
Vol 8 (3) ◽  
Author(s):  
SRIRAM. T ◽  
PANDIDURAI. V
Keyword(s):  
Silver Nanoparticles ◽  
Zea Mays ◽  
Growth Analysis ◽  
Zea Mays L ◽  
In Vitro Growth

IN VITRO GERMINATION AND POLLEN TUBE GROWTH OF MAIZE (ZEA MAYS L.) POLLEN. X. POLLEN SOURCE GENOTYPE AND GIBBERELLIN A3INTERACTIONS*

1982 ◽  
Vol 31 (1-2) ◽  
pp. 105-111 ◽  
Author(s):  
P. L. Pfahler ◽  
M. Wilcox ◽  
D. L. Mulcahy ◽  
D. A. Knauft
Keyword(s):  
Zea Mays ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Zea Mays L ◽  
Tube Growth ◽  
In Vitro Germination

scholarly journals Genome-Wide Transcriptomic Identification and Functional Insight of Lily WRKY Genes Responding to Botrytis Fungal Disease

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 776
Author(s):  
Shipra Kumari ◽  
Bashistha Kumar Kanth ◽  
Ju young Ahn ◽  
Jong Hwa Kim ◽  
Geung-Joo Lee
Keyword(s):  
Abiotic Stress ◽  
Biotic Stress ◽  
Developmental Stages ◽  
Expression Patterns ◽  
Lilium Longiflorum ◽  
Biotic And Abiotic Stress ◽  
Biotic Stresses ◽  
Genome Wide

Genome-wide transcriptome analysis using RNA-Seq of Lilium longiflorum revealed valuable genes responding to biotic stresses. WRKY transcription factors are regulatory proteins playing essential roles in defense processes under environmental stresses, causing considerable losses in flower quality and production. Thirty-eight WRKY genes were identified from the transcriptomic profile from lily genotypes, exhibiting leaf blight caused by Botrytis elliptica. Lily WRKYs have a highly conserved motif, WRKYGQK, with a common variant, WRKYGKK. Phylogeny of LlWRKYs with homologous genes from other representative plant species classified them into three groups- I, II, and III consisting of seven, 22, and nine genes, respectively. Base on functional annotation, 22 LlWRKY genes were associated with biotic stress, nine with abiotic stress, and seven with others. Sixteen unique LlWRKY were studied to investigate responses to stress conditions using gene expression under biotic and abiotic stress treatments. Five genes—LlWRKY3, LlWRKY4, LlWRKY5, LlWRKY10, and LlWRKY12—were substantially upregulated, proving to be biotic stress-responsive genes in vivo and in vitro conditions. Moreover, the expression patterns of LlWRKY genes varied in response to drought, heat, cold, and different developmental stages or tissues. Overall, our study provides structural and molecular insights into LlWRKY genes for use in the genetic engineering in Lilium against Botrytis disease.

scholarly journals Zika Virus Infection Leads to Demyelination and Axonal Injury in Mature CNS Cultures

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 91
Author(s):  
Verena Schultz ◽  
Stephanie L. Cumberworth ◽  
Quan Gu ◽  
Natasha Johnson ◽  
Claire L. Donald ◽  
...  
Keyword(s):  
Nervous System ◽  
Neural Development ◽  
Zika Virus ◽  
Developmental Stages ◽  
Cell Types ◽  
Neural Cells ◽  
Zikv Infection ◽  
Axonal Pathology ◽  
Time Frames

Understanding how Zika virus (Flaviviridae; ZIKV) affects neural cells is paramount in comprehending pathologies associated with infection. Whilst the effects of ZIKV in neural development are well documented, impact on the adult nervous system remains obscure. Here, we investigated the effects of ZIKV infection in established mature myelinated central nervous system (CNS) cultures. Infection incurred damage to myelinated fibers, with ZIKV-positive cells appearing when myelin damage was first detected as well as axonal pathology, suggesting the latter was a consequence of oligodendroglia infection. Transcriptome analysis revealed host factors that were upregulated during ZIKV infection. One such factor, CCL5, was validated in vitro as inhibiting myelination. Transferred UV-inactivated media from infected cultures did not damage myelin and axons, suggesting that viral replication is necessary to induce the observed effects. These data show that ZIKV infection affects CNS cells even after myelination—which is critical for saltatory conduction and neuronal function—has taken place. Understanding the targets of this virus across developmental stages including the mature CNS, and the subsequent effects of infection of cell types, is necessary to understand effective time frames for therapeutic intervention.

Silicon and cadmium interaction of maize (Zea mays L.) plants cultivated in vitro

Biologia ◽  
2021 ◽  
Author(s):  
Zuzana Lukacova ◽  
Denis Liska ◽  
Boris Bokor ◽  
Renata Svubova ◽  
Alexander Lux
Keyword(s):  
Zea Mays ◽  
Zea Mays L
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