Structure and ecdysial process of the larval spiracles of the scarabaeoidea, with special reference to those of Lepidoderma

1967 ◽  
Vol 15 (5) ◽  
pp. 947 ◽  
Author(s):  
HE Hinton
Keyword(s):  
Special Reference ◽  
Electron Micrographs ◽  
Epidermal Cells ◽  
Ambient Atmosphere ◽  
Serial Sections ◽  
Gas Exchanges ◽  
Spiracular Plate

The structure of the larval spiracles of the scarabaeid beetle, Lepidoderma albohirtum Waterh., has been examined by means of serial sections and stereoscan electron micrographs of whole and dissected specimens. Gas exchanges with the ambient atmosphere are effected through aeropyles in the spiracular plate. The aeropyles are of two types: (1) slit-like aeropyles about 4 � long and 0.1-0.5 � wide; and (2) round or oval aeropyles that are usually about 0.2-0.3 u wide. The ecdysial tube is often open in preparations, and this has led to the commonly expressed view that it is the chief or only opening into the spiracular atrium. The open condition of the ecdysial tube in preparations is an artifact. The formation of a new spiracle is briefly described. Cuticular struts project inwards from the peritreme and branch at their apices. Then the apical branches divide and those from different struts anastomose to form the plate and the network immediately below the plate. All of these structures are secreted by very long cytoplasmic projections. The nuclei of the epidermal cells remain in the region of the peritreme and do not enter the main columns of cytoplasm that in due course secrete the cuticular struts. The cytoplasmic columns that form the largest struts consist of projections from many epidermal cells. The chief differences in the structure of the spiracles within the superfamily Scarabaeoidea are briefly noted. A closing apparatus is present in the Trogidae, Lucanidae, Passalidae, and Glaphyrinae but is absent in the Geotrupidae and Scarabaeidae. The ecdysial process in primitive Scarabaeoidea is of the typical elateroid type, whereas specialized Scarabaeoidea have a bulla that carries the ecdysial tube. The modified elateroid process of specialized forms is here named the pseudopanorpoid type. The spiracles of some species of Trox are biforous. Those of other species of Trox and all other Scarabaeoidea examined are cribriform. The cribriform type of spiracle has been evolved on at least two occasions within the superfamily.

The structure of the Spiracles of the cattle tick, Boophilus microplus

1967 ◽  
Vol 15 (5) ◽  
pp. 941 ◽  
Author(s):  
HE Hinton
Keyword(s):  
Electron Microscope ◽  
Ambient Air ◽  
Adult Tick ◽  
Boophilus Microplus ◽  
Ixodid Ticks ◽  
Cattle Tick ◽  
Serial Sections ◽  
Peripheral Part ◽  
Gas Exchanges ◽  
Spiracular Plate

The structures of the nymphal and adult spiracles of the tick, Boophilus microplus, have been examined by means of serial sections and a stereoscan electron microscope. Contrary to the views of recent writers, the functional openings of the spiracle have been found to be holes or aeropyles in the peripheral part of the spiracular plate of the adult tick. The ostium of previous writers is shown to be the ecdysial tube, which is present only in the spiracles of adult ixodid ticks. After the nymphal-adult ecdysis, the ecdysial tube is closed. There is thus no ostium in this stage, as has been claimed by previous writers who supposed that the chief or only route for gas exchanges between the atrium of the spiracle and the ambient air was through the so-called ostium. The ecdysial process of the spiracles of ticks is shown to be basically similar to the ecdysial process of the spiracles of certain insects such as scarabaeid larvae and the larvae of some Diptera-Cyclorrhapha.

Cell morphology, volume, and surface area determinations from multilevel contouring within HVEM micrographs of serial sections and whole-cell mounts

1987 ◽  
Vol 45 ◽  
pp. 588-589
Author(s):  
M. Marko ◽  
A. Leith ◽  
D. Parsons
Keyword(s):  
Surface Area ◽  
Electron Micrographs ◽  
Cell Morphology ◽  
Individual Variation ◽  
Serial Section ◽  
Stereo Pair ◽  
Complex Structures ◽  
Serial Sections ◽  
Surface Areas ◽  
Computer Based

The use of serial sections and computer-based 3-D reconstruction techniques affords an opportunity not only to visualize the shape and distribution of the structures being studied, but also to determine their volumes and surface areas. Up until now, this has been done using serial ultrathin sections.The serial-section approach differs from the stereo logical methods of Weibel in that it is based on the Information from a set of single, complete cells (or organelles) rather than on a random 2-dimensional sampling of a population of cells. Because of this, it can more easily provide absolute values of volume and surface area, especially for highly-complex structures. It also allows study of individual variation among the cells, and study of structures which occur only infrequently.We have developed a system for 3-D reconstruction of objects from stereo-pair electron micrographs of thick specimens.

scholarly journals Variable opacity of glycogen in routine electron micrographs.

1977 ◽  
Vol 25 (9) ◽  
pp. 1069-1073 ◽  
Author(s):  
L E Thornell ◽  
M Sjöström ◽  
U Karlsson ◽  
E Cedergren
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Micrographs ◽  
Periodic Acid ◽  
Frog Muscle ◽  
Nerve Terminals ◽  
Lead Citrate ◽  
Serial Sections ◽  
Transmission Electron ◽  
Reticular Zone

Glycogen in nerve terminals from the reticular zone of frog muscle was identified by transmission electron microscopy of both periodic acid-thiosemicarbazide-silverproteinate treated and UAc-PbCi-stained serial sections. A variable appearance of glycogen in the uranylacetate-lead citrate-stained nerve terminals was seen and is related to the preparative procedure. The study indicates the necessity of cytochemical identification for the assessment of glycogen organization in cells.

DEVELOPMENT OF THE POSTERIOR SPIRACLES IN HYPODERMA (DIPTERA: HYPODERMATIDAE) LINEATUM AND H. BOVIS

1974 ◽  
Vol 106 (2) ◽  
pp. 113-120 ◽  
Author(s):  
V. I. E. Murray
Keyword(s):  
Instar Larva ◽  
Epidermal Cells ◽  
Posterior Spiracle ◽  
The Third ◽  
Spiracular Plate ◽  
Characteristic Features ◽  
Third Instar Larva

AbstractEach posterior spiracle is generally divided into three main parts—posterior spiracular plate, fell and spiracular chambers. The characteristic features of these parts and the moulting processes during the development of the larvae are described in the text. The main features in the development of the third instar larva are the replacement of the epidermal cells by chitin, shortening of the felt chamber and sear cord, increase in the depth of the spiracular chamber, gradual melanization of the posterior spiracle, and then its separation from the dorsal longitudinal trunk prior to pupation.

scholarly journals SERIAL RECONSTRUCTION OF THE CHARACTERISTIC GRANULE OF THE LANGERHANS CELL

1968 ◽  
Vol 36 (3) ◽  
pp. 595-602 ◽  
Author(s):  
Richard W. Sagebiel ◽  
Thomas H. Reed
Keyword(s):  
Electron Microscope ◽  
Electron Micrographs ◽  
Three Dimensional ◽  
Langerhans Cell ◽  
Human Epidermis ◽  
Dimensional Structure ◽  
Serial Sections ◽  
Three Dimensional Structure ◽  
Three Dimensional Models ◽  
The Many

Three-dimensional models of individual granules in the same Langerhans cell were made after analyzing serial sections of human epidermis in the electron microscope. These models revealed that the granule is made up of a flattened or curved orthogonal net of particles which is bounded externally by a limiting membrane and which may be disc-shaped, cup-shaped, or combinations of both shapes. This variety of shapes accounts for the many configurations of the granule seen in individual electron micrographs. Usually, the granule has a vesicular portion at, or near one margin. This demonstration of the three-dimensional structure of the granule establishes the inaccuracy of previously used descriptive terms, the granule should be called simply the "Langerhans cell granule."

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