Callose-containing deposits in relation to root-hair infections of Alnus rubra by Frankia

1990 ◽  
Vol 68 (4) ◽  
pp. 798-802 ◽  
Author(s):  
A. M. Berry ◽  
M. E. McCully
Keyword(s):  
Electron Microscopy ◽  
Hair Cells ◽  
Root Hair ◽  
Vascular Tissue ◽  
Root Hairs ◽  
Alnus Rubra ◽  
Blue Fluorescence ◽  
Electron Dense Material ◽  
Transmission Electron ◽  
Infected Root

Light microscopy, aniline-blue fluorescence histochemistry, and transmission electron microscopy were used to elucidate the nature of localized wall deposition in infected and uninfected root hairs on nodulated roots of Alnus rubra Bong, inoculated with the nitrogen-fixing symbiont, Frankia HFPAr13. Callose-containing papillae were found only in epidermal hair cells and not in cortical or vascular tissue. At the site of successful root-hair wall penetration, transfer cell-like wall ingrowths were elaborated, but callose was not detected. At sites of arrested root-hair infections, complex deposits consisting of callose, fibrillar components, and electron-dense material surrounded the incipient hyphal infection. The cytoplasm of root hairs containing arrested infections was deteriorated compared with successfully infected root hairs.

Use of SEM, X-ray analysis and TEM to localize Fe3+ reduction in roots

1988 ◽  
Vol 46 ◽  
pp. 392-393 ◽  
Author(s):  
William P. Wergin ◽  
P. F. Bell ◽  
Rufus L. Chaney
Keyword(s):  
Electron Microscopy ◽  
Root Hairs ◽  
Rapid Reduction ◽  
X Ray ◽  
Physical Evidence ◽  
Transmission Electron ◽  
Young Root ◽  
Insoluble Precipitate ◽  
Uptake And Transport ◽  
Scanning Electron

In dicotyledons, Fe3+ must be reduced to Fe2+ before uptake and transport of this essential macronutrient can occur. Ambler et al demonstrated that reduction along the root could be observed by the formation of a stain, Prussian blue (PB), Fe4 [Fe(CN)6]3 n H2O (where n = 14-16). This stain, which is an insoluble precipitate, forms at the reduction site when the nutrient solution contains Fe3+ and ferricyanide. In 1972, Chaney et al proposed a model which suggested that the Fe3+ reduction site occurred outside the cell membrane; however, no physical evidence to support the model was presented at that time. A more recent study using the PB stain indicates that rapid reduction of Fe3+ occurs in a region of the root containing young root hairs. Furthermore the most pronounced activity occurs in plants that are deficient in Fe. To more precisely localize the site of Fe3+ reduction, scanning electron microscopy (SEM), x-ray analysis, and transmission electron microscopy (TEM) were utilized to examine the distribution of the PB precipitate that was induced to form in roots.

Root hair deformation in the infection process of Alnus rubra

1983 ◽  
Vol 61 (11) ◽  
pp. 2863-2876 ◽  
Author(s):  
Alison M. Berry ◽  
John G. Torrey
Keyword(s):  
Root Hair ◽  
Cell Walls ◽  
Root Hairs ◽  
Infection Process ◽  
Alnus Rubra ◽  
Pseudomonas Cepacia ◽  
Developmental Studies ◽  
Experimental Conditions ◽  
Root Hair Cell ◽  
Root Hair Deformation

Structural and cell developmental studies of root hair deformation in Alnus rubra Bong. (Betulaceae) were carried out following inoculation with the soil pseudomonad Pseudomonas cepacia 85, alone or in concert with Frankia, and using axenically grown seedlings. Deformational changes can be observed in elongating root hairs within 2 h of inoculation with P. cepacia 85. These growing root hairs become branched or multilobed and highly modified from the single-tip growth of axenic root hairs. The cell walls of deformed hairs are histologically distinctive when stained with the fluorochrome acridine orange. Filtrate studies using P. cepacia 85 suggest that the deforming substance is not a low molecular weight compound. Root hair deformation and the associated wall histology are host specific in that Betula root hairs show none of these responses when grown and inoculated in the experimental conditions described. The bacterially induced changes in root hair cell walls during deformation may create a chemically and physically modified substrate for Frankia penetration, and the deformation itself may serve to entrap and enclose the filamentous organism, allowing wall dissolution and entry. Thus these events represent a complex host response as a precondition to successful nodulation.

Cis-Diamminedichloroplatinum (II) Ototoxicity in the Guinea Pig

1981 ◽  
Vol 89 (4) ◽  
pp. 638-645 ◽  
Author(s):  
Scott A. Estrem ◽  
Richard W. Babin ◽  
Jai H. Ryu ◽  
Kenneth C. Moore
Keyword(s):  
Electron Microscopy ◽  
Hair Cells ◽  
Supporting Cell ◽  
Cell Ultrastructure ◽  
Outer Hair Cells ◽  
Detectable Change ◽  
Supporting Cells ◽  
Apical Portion ◽  
Ultrastructural Evidence ◽  
Transmission Electron

Cochleas from 12 guinea pigs were evaluated using light, scanning, and transmission electron microscopy after systemic administration of cis-diamminedichloroplatinum (cis-DDP). Administration of cis-DDP resulted in loss of the Preyer reflex and degeneration of outer hair cells (OHC) with increased dose. The OHC degeneration was most pronounced in the basal turns of the cochlea with greatest severity in the inner row. Ultrastructural evidence of OHC degeneration included dilatation of the parietal membranes, softening of the cuticular plate, increased vacuolization and increased numbers of lysosome-like bodies in the apical portion of the cell. Supporting cells appeared more sensitive than OHC. Alteration of supporting cell ultrastructure preceded detectable change in OHC. Injury to the supporting cells was noted with intracellular vesiculation and increased autophagocytosis.

Ontogeny of Alnus rubra – Alpova diplophloeus ectomycorrhizae. II. Transmission electron microscopy

1989 ◽  
Vol 67 (1) ◽  
pp. 201-210 ◽  
Author(s):  
H. B. Massicotte ◽  
C. A. Ackerley ◽  
R. L. Peterson
Keyword(s):  
Electron Microscopy ◽  
Epidermal Cells ◽  
Root Cap ◽  
Alnus Rubra ◽  
Golgi Bodies ◽  
Hartig Net ◽  
Transmission Electron ◽  
Meristem Zone ◽  
Basal Portion ◽  
Branching System

Ultrastructural features of the two symbionts in ectomycorrhizae formed between Alnus rubra and Alpova diplophloeus change with developmental stage. In the root cap – meristem zone, hyphae penetrate between vacuolated root cap cells and become appressed to epidermal cells containing small vacuoles, plastids with starch, numerous Golgi bodies, mitochondria, and endoplasmic reticulum cisternae. In the young Hartig net zone, hyphae with few vacuoles penetrate between vacuolated epidermal cells that still contain numerous Golgi bodies but now have plastids with small starch grains. Hartig net hyphae begin to branch and eventually form a complex branching system in the mature Hartig net zone. Hartig net hyphae in the basal portion of the ectomycorrhizae synthesize lipid and finally become vacuolated.

Ultrastructural Changes in the Cochlea of the Guinea Pig after Fast Neutron Irradiation

1994 ◽  
Vol 110 (4) ◽  
pp. 419-427 ◽  
Author(s):  
Ilsa Schwartz ◽  
Chong-Sun Kim ◽  
See-Ok Shin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hair Cell ◽  
Neutron Irradiation ◽  
Hair Cells ◽  
Cell Damage ◽  
Outer Hair Cells ◽  
Transmission Electron ◽  
Fast Neutron Irradiation ◽  
Hair Cell Damage

Guinea pigs were irradiated with fast neutrons. After a single dose of 2, 6, 10, or 15 Gy was applied, scanning and transmission electron microscopy of the temporal bone was performed to assess the effect of fast neutron irradiation on the cochlea. Outer hair cell damage appeared with neutron irradiation of more than 10 Gy, and Inner hair cell damage with neutron Irradiation of more than 15 Gy. Outer hair cells were more severely damaged than Inner hair cells. No statistically significant differences were found in damage of basal, middle, and apical turns. The second and third rows of outer hair cells were more severely damaged than the first row of outer hair cells. The most significant findings in transmission electron microscopy were clumping of chromatin and extension of the heterochromatin in the nuclei of hair cells. The cytoplasmic changes were sequestration of cytoplasm, various changes of mitochondria, formation of vacuoles, and irregularly arranged stereocilia. The morphologic change in stria vascularis was intercellular and perivascular fluid accumulation. It appeared to be a reversible process.

Spermiogenesis and spermatozoon of the tapeworm Parabothriocephalus gracilis (Bothriocephalidea): Ultrastructural and cytochemical studies

2010 ◽  
Vol 55 (1) ◽  
Author(s):  
Lenka Šípková ◽  
Céline Levron ◽  
Mark Freeman ◽  
Tomáš Scholz
Keyword(s):  
Electron Microscopy ◽  
Anterior Extremity ◽  
Mature Spermatozoon ◽  
Dense Material ◽  
Apical Region ◽  
Cortical Microtubules ◽  
Electron Dense Material ◽  
Dense Granules ◽  
Cytoplasmic Extension ◽  
Transmission Electron

AbstractSpermiogenesis and spermatozoon ultrastructure of the tapeworm Parabothriocephalus gracilis were described using transmission electron microscopy (TEM). Spermiogenesis is characterized by the formation of a zone of differentiation with two centrioles associated with striated rootlets, and an intercentriolar body between them. The two flagella undergo a rotation of 90° until they become parallel to the median cytoplasmic extension with which they fuse. Electron-dense material is present in the apical region of the zone of differentiation in the early stages of spermiogenesis. This electron-dense material is characteristic for the orders Bothriocephalidea and Diphyllobothriidea. The mature spermatozoon contains two axonemes of the 9 + ‘1’ trepaxonematan pattern, nucleus, parallel cortical microtubules and electron-dense granules of glycogen. The anterior extremity of the spermatozoon exhibits a single helical electron-dense crested body 130 nm thick. One of the most interesting features is the presence of a ring of cortical microtubules surrounding the axoneme. This character has been reported only for species of the order Bothriocephalidea and may be unique in this cestode group.

scholarly journals A role for the RabA4b effector protein PI-4Kβ1 in polarized expansion of root hair cells in Arabidopsis thaliana

2006 ◽  
Vol 172 (7) ◽  
pp. 991-998 ◽  
Author(s):  
Mary L. Preuss ◽  
Aaron J. Schmitz ◽  
Julie M. Thole ◽  
Heather K.S. Bonner ◽  
Marisa S. Otegui ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Hair Cells ◽  
Root Hair ◽  
Root Hairs ◽  
Developmentally Regulated ◽  
Domain Specific ◽  
Polarized Secretion ◽  
Phosphatidylinositol 4 ◽  
Golgi Network ◽  
Root Hair Cells

The RabA4b GTPase labels a novel, trans-Golgi network compartment displaying a developmentally regulated polar distribution in growing Arabidopsis thaliana root hair cells. GTP bound RabA4b selectively recruits the plant phosphatidylinositol 4-OH kinase, PI-4Kβ1, but not members of other PI-4K families. PI-4Kβ1 colocalizes with RabA4b on tip-localized membranes in growing root hairs, and mutant plants in which both the PI-4Kβ1 and -4Kβ2 genes are disrupted display aberrant root hair morphologies. PI-4Kβ1 interacts with RabA4b through a novel homology domain, specific to eukaryotic type IIIβ PI-4Ks, and PI-4Kβ1 also interacts with a Ca2+ sensor, AtCBL1, through its NH2 terminus. We propose that RabA4b recruitment of PI-4Kβ1 results in Ca2+-dependent generation of PI-4P on this compartment, providing a link between Ca2+ and PI-4,5P2–dependent signals during the polarized secretion of cell wall components in tip-growing root hair cells.

The homeobox gene GLABRA2 is required for position-dependent cell differentiation in the root epidermis of Arabidopsis thaliana

Development ◽  
1996 ◽  
Vol 122 (4) ◽  
pp. 1253-1260 ◽  
Author(s):  
J.D. Masucci ◽  
W.G. Rerie ◽  
D.R. Foreman ◽  
M. Zhang ◽  
M.E. Galway ◽  
...  
Keyword(s):  
Epidermal Cell ◽  
Hair Cells ◽  
Root Hair ◽  
Root Hairs ◽  
Homeobox Gene ◽  
Epidermal Cells ◽  
Wild Type ◽  
Cell Identity ◽  
Root Epidermis ◽  
Root Hair Cells

The role of the Arabidopsis homeobox gene, GLABRA 2 (GL2), in the development of the root epidermis has been investigated. The wild-type epidermis is composed of two cell types, root-hair cells and hairless cells, which are located at distinct positions within the root, implying that positional cues control cell-type differentiation. During the development of the root epidermis, the differentiating root-hair cells (trichoblasts) and the differentiating hairless cells (atrichoblasts) can be distinguished by their cytoplasmic density, vacuole formation, and extent of elongation. We have determined that mutations in the GL2 gene specifically alter the differentiation of the hairless epidermal cells, causing them to produce root hairs, which indicates that GL2 affects epidermal cell identity. Detailed analyses of these differentiating cells showed that, despite forming root hairs, they are similar to atrichoblasts of the wild type in their cytoplasmic characteristics, timing of vacuolation, and extent of cell elongation. The results of in situ nucleic acid hybridization and GUS reporter gene fusion studies show that the GL2 gene is preferentially expressed in the differentiating hairless cells of the wild type, during a period in which epidermal cell identity is believed to be established. These results indicate that the GL2 homeodomain protein normally regulates a subset of the processes that occur during the differentiation of hairless epidermal cells of the Arabidopsis root. Specifically, GL2 appears to act in a cell-position-dependent manner to suppress hair formation in differentiating hairless cells.

The life cycle of Lagena radicicola, an oomycetous parasite of wheat roots

1990 ◽  
Vol 68 (4) ◽  
pp. 813-824 ◽  
Author(s):  
D. J. S. Barr ◽  
N. L. Désaulniers
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Life Cycle ◽  
Root Hairs ◽  
Wheat Roots ◽  
Virus Like Particles ◽  
Transmission Electron ◽  
Resting Spores ◽  
Single Host ◽  
Infected Cells

Lagena radicicola Vanterpool & Ledingham is an obligate parasite inside root hairs and epidermal cells. It was cultured in a unifungal state on wheat in pots. The life cycle was examined by both light and transmission electron microscopy. The thallus developed inside a single host cell and formed either a single sporangium or one to four resting spores. Zoospore cleavage was completed in vesicles outside the root. The resting spores were similar to oospores in their development and cytology, but there was no evidence of cell fusion and sexuality. Virus-like particles were seen in 3- to 12-month-old cultures, and infected cells became degenerate. Key words: Oomycetes, ultrastructure, virus-like particles, biocontrol.

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