Fine structure of Tyloses in three species of the Myrtaceae

1967 ◽  
Vol 15 (1) ◽  
pp. 25 ◽  
Author(s):  
RC Foster
Keyword(s):  
Fine Structure ◽  
Granular Material ◽  
Double Layer ◽  
Layered Structure ◽  
Outer Layer ◽  
Secondary Wall ◽  
Pit Membrane ◽  
Ray Cell

The tylosis wall in Eucalyptus obliqua L'Herit. is shown to be composed of two microfibrillar layers. The outer layer (T1), with randomly orientated microfibrils, is covered with amorphous granular material. The inner layer (T2) is multilamellate. In sclerosed tyloses of E. miniata A. Cunn., each lamella of T2 is composed of many layers of microfibrils. Simple pits, delineated by circumferentially orientated microfibrils, are found in both sclerosed and non-sclerosed tyloses. The tylosis in E. obliqua is shown to arise from a two-layered structure formed within the secondary wall of the ray cell. This layer extends into the pit chamber, covering the pit membrane on the ray side. Following the breakdown of the vestures and the pit membrane, this double layer bulges out into the vessel to form the tylosis.

Review — The Orientation of Cellulose Microfibrils in the cell walls of Tracheids in Conifers

IAWA Journal ◽  
2005 ◽  
Vol 26 (2) ◽  
pp. 161-174 ◽  
Author(s):  
Hisashi Abe ◽  
Ryo Funada
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Outer Layer ◽  
Cell Walls ◽  
Secondary Wall ◽  
Middle Layer ◽  
Cellulose Microfibrils ◽  
Conifer Species ◽  
Predominant Orientation ◽  
Scanning Electron

We examined the orientation of cellulose microfibrils (Mfs) in the cell walls of tracheids in some conifer species by field emission-scanning electron microscopy (FE-SEM) and developed a model on the basis of our observations. Mfs depositing on the primary walls in differentiating tracheids were not well-ordered. The predominant orientation of the Mfs changed from longitudinal to transverse, as the differentiation of tracheids proceeded. The first Mfs to be deposited in the outer layer of the secondary wall (S1 layer) were arranged as an S-helix. Then the orientation of Mfs changed gradually, with rotation in the clockwise direction as viewed from the lumen side of tracheids, from the outermost to the innermost S1 layer. Mfs in the middle layer of the secondary wall (S2 layer) were oriented in a steep Z-helix with a deviation of less than 15° within the layer. The orientation of Mfs in the inner layer of the secondary wall (S3 layer) changed, with rotation in a counterclockwise direction as viewed from the lumen side, from the outermost to the innermost S3 layer. The angle of orientation of Mfs that were deposited on the innermost S3 layer varied among tracheids from 40° in a Z-helix to 20° in an S-helix.

An Electron Microscope study of a Small Free-living Amoeba (Hartmanella astronyxis)

1959 ◽  
Vol s3-100 (49) ◽  
pp. 13-15
Author(s):  
K. DEUTSCH ◽  
M. M. SWANN
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Cell Membrane ◽  
Nuclear Membrane ◽  
Layered Structure ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Honeycomb Structure ◽  
Free Living ◽  
Free Living Amoeba

The fine structure of a species of small free-living amoeba, Hartmanella astronyxis, has been investigated. The mitochondria resemble those of other species of amoeba. Structureless bodies of about the same size as mitochondria are sometimes found in association with them. Double membranes are common in the cytoplasm, and may show granules along their outer borders. The nuclear membrane is a double-layered structure, with a honeycomb structure evident in tangential sections. The cell membrane is also double-layered, or occasionally multi-layered.

scholarly journals Oxidation Behavior of Ferritic Steel T22 Exposed to Supercritical Water

2019 ◽  
Vol 38 (2019) ◽  
pp. 476-484 ◽  
Author(s):  
Zhongliang Zhu ◽  
Hasan Izhar Khan ◽  
Qi Cao ◽  
Naiqiang Zhang
Keyword(s):  
Iron Oxide ◽  
Supercritical Water ◽  
Layered Structure ◽  
Outer Layer ◽  
Ferritic Steel ◽  
Oxidation Behavior ◽  
Spinel Oxide ◽  
Initial Oxidation ◽  
Exposure Temperature ◽  
Oxidation Stage

AbstractThe oxidation tests of Ferritic Steel T22 exposed to supercritical water (SCW) at 540–620°C and 25 MPa was performed for up to 1000 h. The oxidation rate increased with increasing exposure temperature and time. Oxide films formed on T22 have a double-layered structure with an outer layer consisting of iron oxide and an inner layer consisting of spinel oxide. Numerous pores on the surface can be observed at the initial oxidation stage while they seemed to heal with increasing exposure time at 620°C. Cracks occurred along grain boundaries in the oxide scale when T22 exposed for 200 h at 620°C. The influence of time and temperature on the oxidation of Ferritic Steel T22 was discussed.

scholarly journals The Secrets of Beautiful Hair: Why is it Flexible and Elastic?

Cosmetics ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 40 ◽  
Author(s):  
Mikako Ezure ◽  
Noriyuki Tanji ◽  
Yukari Nishita ◽  
Takashi Mizooku ◽  
Shinobu Nagase ◽  
...  
Keyword(s):  
Physical Properties ◽  
Layered Structure ◽  
Outer Layer ◽  
New Technology ◽  
Selective Reduction ◽  
Cell Distribution ◽  
Cortical Cells ◽  
The Difference ◽  
The Relationship ◽  
Hair Surface

Beautiful hair, so called “SHINAYAKA” hair in Japanese, has a good appearance not only when stationary but also when in motion, and it is a highly desirable hair condition for Japanese consumers. We investigated such SHINAYAKA hair, which was selected by sensory evaluation, for the relationship between physical properties, such as flexibility and elasticity, and hair structure. It has already been reported that human hair cortical cells have two types, similar to wool: the ortho-like cortex and the para-like cortex. Microscopic observation revealed that the ortho-like cortex is distributed in the outer layer of the hair (near the hair surface) and the para-like cortex exists in the inner layer (near the center of the fiber). This cell distribution, a concentric double-layered structure, was deemed to be a characteristic of SHINAYAKA hair. Furthermore, analysis of physical properties showed the difference between the elasticity of the outer layer and inner layer, and that this difference was bigger in SHINAYAKA hair compared to other hair. This phenomenon was observed not only in Japanese hair, but also in Caucasian hair. In addition, we have developed a new technology for creating “SHINAYAKA” hair by treatment with succinic acid. Inflexible and inelastic hair can be changed by this treatment, and its flexibility and elasticity improve by selective reduction of stiffness of the outer layer.

The fine structure of the pits of Eucalyptus regnans (F. Muell.) and their relation to the movement of liquids into the wood

1960 ◽  
Vol 8 (1) ◽  
pp. 51 ◽  
Author(s):  
J Cronshaw
Keyword(s):  
Secondary Wall ◽  
Structural Features ◽  
Cellulose Microfibrils ◽  
Primary Wall ◽  
Detailed Structure ◽  
Eucalyptus Regnans ◽  
Pit Membrane ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Ray Parenchyma Cells

Observstion in the electron microscope of carbon replicas of the pits of vessels, ray parenchyma cells, fibres, and tracheids of Eucalyptus regnans has shown the detailed structure of the pit borders and the pit closing membranes. In all cases in the mature wood the primary wall is left apparently without modification as the pit membrane. Unlike the borders of the pits of fibre tracheids and tracheids, the pit borders of the vessels are not separate; the cellulose microfibrils of a border may be common to several pits. The pit borders of fibre traoheids and tracheids are developed as separate entities and have a structure similar to the pit borders of softwood tracheids. The structure of the secondary wall layers associated with the pits is described and related to the structure of the pits. The fine structural features of the pits, especially of the pit closing membranes, are discussed in relation to the movement of liquids into wood.

scholarly journals Further Observations on the Fine Structure of Chrysochromulina Ericina Parke & Manton

1961 ◽  
Vol 41 (1) ◽  
pp. 145-155 ◽  
Author(s):  
I. Manton ◽  
G. F. Leedale
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Cell Surface ◽  
Light Microscopy ◽  
Flat Plate ◽  
Outer Layer ◽  
Living Cells ◽  
Layered Plates ◽  
Thin Sections ◽  
Micro Anatomy

C. ericina Parke & Manton has been re-investigated to add salient features of micro-anatomy from the electron microscopy of thin sections and also to add photographs of living cells taken with anoptral contrast light microscopy.The most important new observations concern the scales which are shown to be essentially two-layered plates in which the layers in the very large spined scales have become separated except at their edges, with the outer layer greatly hypertrophied to produce a hollow spine with a flared base closed at the bottom by a flat plate. The patterns of external marking on the two layers are very similar in both plate-scales and spines in this species and the orientation of both with respect to the cell surface has been demonstrated by a section of the scales in situ.

The fine structure of conidial development in the genus Torula. IV. T. thermophila Cooney & Emerson

1976 ◽  
Vol 22 (8) ◽  
pp. 1102-1112 ◽  
Author(s):  
D. H. Ellis ◽  
D. A. Griffiths
Keyword(s):  
Fine Structure ◽  
Cell Walls ◽  
Secondary Wall ◽  
Wall Layer ◽  
Outer Electron ◽  
Humicola Insolens ◽  
Spore Release ◽  
Transparent Zone ◽  
Conidial Development ◽  
Dense Zone

Torula thermophila produced typical chlamydospores either as intercalary chains within prostrate hyphae or as terminal swellings on short, lateral, hyphal branches. Mature chlamydospores were spherical, dark brown, smooth-surfaced structures with thick, single-layered cell walls (= secondary wall layer) usually differentiated into an outer electron-dense zone and an inner electron-transparent zone. Disarticulation and spore release occurred after the disintegration of the original hyphal wall.The thallospores of T. thermophila arise in a manner different from the blastospores produced by other species of Torula and are structurally more closely related to the spores produced by Humicola insolens. However until further work has been completed on spore development in the Torulu-Humicola complex of fungi the name T. thermophila is retained.

scholarly journals THE AXON HILLOCK AND THE INITIAL SEGMENT

1968 ◽  
Vol 38 (1) ◽  
pp. 193-201 ◽  
Author(s):  
Sanford L. Palay ◽  
Constantino Sotelo ◽  
Alan Peters ◽  
Paula M. Orkand
Keyword(s):  
Plasma Membrane ◽  
Fine Structure ◽  
Granular Material ◽  
Internal Structure ◽  
Electron Micrographs ◽  
Initial Segment ◽  
Special Function ◽  
Structural Features ◽  
Dense Layer ◽  
Axon Hillock

Axon hillocks and initial segments have been recognized and studied in electron micrographs of a wide variety of neurons. In all multipolar neurons the fine structure of the initial segment has the same pattern, whether or not the axon is ensheathed in myelin. The internal structure of the initial segment is characterized by three special features: (a) a dense layer of finely granular material undercoating the plasma membrane, (b) scattered clusters of ribosomes, and (c) fascicles of microtubules. A similar undercoating occurs beneath the plasma membrane of myelinated axons at nodes of Ranvier. The ribosomes are not organized into Nissl bodies and are too sparsely distributed to produce basophilia. They vanish at the end of the initial segment. Fascicles of microtubules occur only in the axon hillock and initial segment and nowhere else in the neuron. Therefore, they are the principal identifying mark. Some speculations are presented on the relation between these special structural features and the special function of the initial segment.

Torus Structure and Development in the Woods of Ulmus Alata Michx., Celtis Laevigata Willd., and Celtis Occidentalis L.

IAWA Journal ◽  
1990 ◽  
Vol 11 (1) ◽  
pp. 71-83 ◽  
Author(s):  
Roland R. Dute ◽  
Ann E. Rushing
Keyword(s):  
Secondary Wall ◽  
Small Diameter ◽  
Three Dimensions ◽  
Central Layer ◽  
Tracheary Elements ◽  
Pit Membrane ◽  
Celtis Occidentalis ◽  
Celtis Laevigata ◽  
Ulmus Alata ◽  
Grooved Wheel

Pit membranes between tracheary elements of Ulmus alata, Celtis laevigata, and Celtis occidentalis often contained tori. The degree of development of tori varied and was greatest in those membranes connecting elements of small diameter. Complete tori consisted of two wall thickenings adjoined by a central layer. In three dimensions the shape of the torus often approximated a grooved wheel. Initiation of thickening in the pit membrane occurred first on the side of the older cell and was well underway prior to the beginning of secondary wall synthesis. Torus formation resulted from the thickening of the primary walls of the pit membrane. Development of the torus was associated with membranous vesicles and cisternae but not with microtubule complexes as was reported in Osmanthus. The pit membranes in this study are capable of aspiration, and the tori may prevent rupture of the pit membrane during this process.

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