Morphological aspects of the shedding of surface layers from peanut roots

1997 ◽  
Vol 75 (4) ◽  
pp. 607-611 ◽  
Author(s):  
Eiji Uheda ◽  
Yoko Akasaka ◽  
Hiroyuki Daimon
Keyword(s):  
Arachis Hypogaea ◽  
Cell Separation ◽  
Cell Walls ◽  
Separation Process ◽  
Surface Layers ◽  
Outer Cortex ◽  
Electron Microscopic ◽  
Intact Cells ◽  
Morphological Aspects ◽  
Microscopic Studies

Epidermal cells and cells originating in the outer cortex form the surface layers of peanut (Arachis hypogaea) roots, the outermost of which separate and shed from the periphery. Shedding takes place continuously and over the whole surface of the root. Light and electron microscopic studies revealed that the shedding of surface layers involves modification of cell walls and separation of intact cells. Wall breakdown, as well as the expansion of cells resulting from wall breakdown, might facilitate the separation of intact cells. Examination of enzymes revealed that cellulase showed much higher activity in the shedding layers than in the remaining tissues. The results suggest that the cell separation process in peanut roots involves a wall-degrading enzyme-mediated mechanism. Key words: Arachis hypogaea, morphology, root, shedding, surface layers, wall breakdown.

scholarly journals Differential distributions in tissues and efficacies of aztreonam and ceftazidime and in vivo bacterial morphological changes following treatment.

1997 ◽  
Vol 41 (2) ◽  
pp. 401-409 ◽  
Author(s):  
A Turcotte ◽  
M Simard ◽  
N J Morin ◽  
D Beauchamp ◽  
M G Bergeron
Keyword(s):  
Cell Walls ◽  
Morphological Changes ◽  
Enterobacter Cloacae ◽  
Control Group ◽  
Electron Microscopic ◽  
Penetration Ratio ◽  
Microscopic Studies ◽  
Bow Tie ◽  
Fibrin Clots

The differential tissue distributions of aztreonam and ceftazidime within fibrin clots infected with Pseudomonas aeruginosa, Enterobacter cloacae, and Serratia marcescens, their efficacies, and the in vivo bacterial morphological changes induced by these drugs were evaluated. Rabbits were given intravenously a single dose of 100 mg of either agents/kg of body weight. In the cores of the clots, the peak levels of both drugs were much lower than those observed in the peripheries and in serum. Aztreonam's half-lives within the peripheries and in the cores of the fibrin clots were up to six times higher than observed in serum, while ceftazidime's half-lives in clots were twice that observed in serum. This resulted in a much greater penetration ratio for aztreonam than for ceftazidime. Both drugs controlled the growth of P. aeruginosa in vivo, but E. cloacae and S. marcescens responded better to ceftazidime. Morphological changes were more abundant in the peripheries than in the cores of the clots. In the control group, P. aeruginosa's morphology in the cores was different than that in the peripheries of the clots. Against P. aeruginosa, aztreonam did induce morphological changes in the cores while ceftazidime did not. Electron microscopic studies revealed that morphological changes associated with aztreonam seemed different than those of ceftazidime. Along with elongation of bacteria, more bow tie and herniated bacteria were observed with aztreonam. Though both agents selectively affect PBP 3, as manifested by elongated bacteria, they induce in the peripheries of the clots thickening, breaks, and detachment in bacterial cell walls, alterations which are generally associated with antibiotics affecting PBP 1a and 1b.

scholarly journals Dipotassium tetramethyl osmate: a stain for electron microscopy.

1975 ◽  
Vol 23 (2) ◽  
pp. 123-127 ◽  
Author(s):  
C C Hinckley ◽  
J A Murphy
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Cell Ultrastructure ◽  
Outer Cell ◽  
Lead Citrate ◽  
Electron Microscopic ◽  
Methanol Solutions ◽  
Microscopic Studies ◽  
Cell Storage

Methanol solutions of dipotassium tetramethyl osmate (DTMO) have been found to be useful as general stains in electron microscopic studies of plant and fungal ultrastructure. The stain solutions are easy to prepare, stable when anhydrous and convenient to use. Although generally similar in staining to lead citrate stains, some elements of cell ultrastructure appear different with dipotassium tetramethyl osmate staining, particularly the outer cell walls of fungi. Indications of specific precipitate-producing reactions in cell storage areas are observed.

Structure and assembly of bacterial surface layers composed of regular arrays of subunits

1974 ◽  
Vol 268 (891) ◽  
pp. 147-153 ◽  
Keyword(s):  
Self Assembly ◽  
Cell Walls ◽  
Surface Layers ◽  
Intact Cells ◽  
Bacterial Surface ◽  
Outer Membranes ◽  
And Function ◽  
Isolated Cell ◽  
Regular Arrays ◽  
Intact Bacterium

Regular arrays of subunits are observed on the surfaces of many bacteria, and the structure and function of such an array are being examined in a study of the Gram-negative bacterium Acinetobacter strain MJT/F5/199A. The subunits are on the surface of the outer membrane and are visible in electron micrographs of freeze-etched intact cells and of negatively stained preparations of isolated cell walls and outer membranes. The surface subunits can be detached from the membrane by various treatments and will then reassemble spontaneously to form the same regular pattern as that seen on the intact bacterium. The results of studies of the properties of the self-assembly system are described and its relevance to the formation of surface layers composed of regular arrays of subunits in intact bacteria discussed.

scholarly journals CELLULAR CHARACTERISTICS OF 3 SWEET CHERRIES WITH DIFFERENT SUSCEPTIBILITIES TO RAIN CRACKING

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 667f-667
Author(s):  
M. Meheriuk ◽  
D.-L. McKenzie ◽  
L. Veto
Keyword(s):  
Cell Walls ◽  
Mineral Content ◽  
Sweet Cherry ◽  
Resistant Cultivar ◽  
Electron Microscopic ◽  
Low Resistance ◽  
Fruit Cracking ◽  
Sweet Cherries ◽  
Microscopic Studies ◽  
Sweet Cherry Cultivars

Electron microscopic studies were conducted on `Sue', `Lapins' and `Van' sweet cherry cultivars which have a high, moderate and low resistance to rain cracking, respectively. Epidermal and hypodermal cells showed differences in size and number. Sue, the resistant cultivar, contained an additional thin elongated cell rich in protein matter, in the hypodermal layer. The three cultivars also showed differences in the cell walls and vacuoles. However, mineral content of the epidermal and hypodermal layers showed no relationship to incidence of fruit cracking.

Resistant biomacromolecules as major contributors to kerogen

1991 ◽  
Vol 333 (1268) ◽  
pp. 329-337 ◽  
Keyword(s):  
Cell Walls ◽  
Chemical Characterization ◽  
Type I ◽  
Electron Microscopic ◽  
Alternative Source ◽  
Plant Cuticles ◽  
Microscopic Studies ◽  
Water Plants ◽  
Waxy Crude Oils

Current research concerning the chemical characterization of organic macromolecules present in wellpreserved fossilized materials with known morphologies revealed by (electron) microscopic studies results in the recognition of unknown, resistant biomacromolecules in a variety of organisms. It is shown that highly aliphatic, non-saponifiable biomacromolecules in cell walls of algae (algaenans) have unique structures, probably as a result of different biosynthetic pathways and that they consist of n -alkyl-, isoprenoid and tricyclic alkyl units. It is also becoming clear that algaenans are structurally different from the highly aliphatic, non-saponifiable biomacromolecules occurring in plant cuticles (cutans), periderm tissue (suberans), some sporopollenins and in tegmens of seeds of water plants. All these types of aliphatic biomacromolecules are highly resistant and therefore selectively preserved in the geosphere. In particular, Type I and II kerogens consist mainly, in some cases exclusively, of these aliphatic biomacromolecules. Polysesquiterpenoids and polyditerpenoids occur in fresh and fossil angiosperm and gymnosperm resins respectively and also show resistant behaviour in the geosphere. Some waxy crude oils contain large amounts of compounds derived from these substances after thermal cracking. A completely new polyphenol type of biomacromolecule was encountered in several fossilized outer walls of seeds (testae) of water plants. Preliminary results indicate that this phenolic biomacromolecule is an alternative source of phenolic moieties in lignites and coals. The significance of lignin as a source of phenolic moieties in subsurface organic matter (e.g. vitrinites) is probably overestimated.

Electron Microscopic Studies on Streptococci

1970 ◽  
Vol 28 ◽  
pp. 194-195
Author(s):  
JOHN SWANSON M.D.
Keyword(s):  
Cell Walls ◽  
Teichoic Acid ◽  
Chemical Components ◽  
Group A Streptococci ◽  
Electron Microscopic ◽  
Histochemical Methods ◽  
Specific Polysaccharide ◽  
Microscopic Studies ◽  
Group A ◽  
Comparative Examination

Group A streptococci contain a variety of chemical components in their cell walls. The major components are mucopeptide, group-specific polysaccharide, protein constituents (M,T, and R), and teichoic acid. Investigations have been carried out to determine the location of each of these classes of chemical components. The techniques used include simple, comparative examination of selected strains that lack or possess a particular component, electron histochemical methods, immunoferritin methods, and extraction or removal of a particular component.

An ultrastructural study of the pathogenesis of the arteriosclerotic lesions in the spontaneous hypertensive (SHR) rat strain

1978 ◽  
Vol 36 (2) ◽  
pp. 482-483
Author(s):  
G. Yajima ◽  
S. Kurihara ◽  
M. Ida ◽  
K. Aihara ◽  
G. Asano ◽  
...  
Keyword(s):  
High Frequency ◽  
Spontaneous Hypertension ◽  
Hypertensive Rats ◽  
Electron Microscopic ◽  
Morphological Aspects ◽  
Solid Diet ◽  
Specific Strain ◽  
Microscopic Studies ◽  
Rat Strain ◽  
The University

The spontaneous hypertensive rats are the strain which was isolated by Okamoto et al and is known to cause high frequency of spontaneous hypertension in later stage of life. Some of them are also recongnized to have high frequency of the cerebro-vascular accident and is also designated as apoplexy prone strain. The genetic and etiological factors of this spontaneous hypertension are the matters of the extensive survey of the investigators, however, the morphological aspects of this specific strain of causing the hypertension still await further confirmation in future. In this viewpoint, the authors have undertaken the electron microscopic and cytochemical electron microscopic studies of the various arteries in a rather extensive manner.The spontaneous hypertensive rats were supplied from the animal room of the University of Kyoto by courtesy of Drs. Okamoto and Yamori. The rats were kept on the commericially available solid diet and sytolic blood pressure was measured and scored daily.

Trichothecium roseum, a mycoparasite of Sclerotinia sclerotiorum

1993 ◽  
Vol 71 (12) ◽  
pp. 1631-1638 ◽  
Author(s):  
H. C. Huang ◽  
E. G. Kokko
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Cell Walls ◽  
Electron Microscopic ◽  
Trichothecium Roseum ◽  
Moist Sand ◽  
Dual Cultures ◽  
Transmission Electron ◽  
Bean Plants ◽  
Transmission Electron Microscopic ◽  
Microscopic Studies

Among sclerotia of Sclerotinia sclerotiorum collected from diseased bean plants in a field near Lethbridge in 1987 and 1988, 30 and 16%, respectively, were contaminated by Trichothecium roseum. Laboratory studies showed that T. roseum is a mycoparasite of S. sclerotiorum, able to infect and destroy sclerotia in dual cultures on potato dextrose agar. Among sclerotia inoculated with spores of T. roseum and incubated for 4 weeks on moist sand, 54 and 43% were infected and killed by the isolates TR-4 and TR-6, respectively. Transmission electron microscopic studies of infected sclerotia revealed that hyphae of T. roseum entered the rind tissue by penetrating the melanized cell walls or via junctions between cells. Lysis of host cell walls occurred at penetration sites. Hyphae of T. roseum ramified in cortical and medullary tissues, destroying the sclerotium. In sclerotia with light infections of T. roseum, numerous cortical and (or) medullary cells showed cytoplasmic granulation and vacuolization without direct association with the mycoparasitic hyphae. Key words: biocontrol, hyperparasite, mycoparasitism.

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