Gross morphological and surface ultrastructural investigation on the gills of the European barracuda Sphyraena sphyraena

Investigation of the spontaneous pituitary adenomas in rat have been limited mainly to light microscopic study. Furth et al. (1973) described them as chromophobic, secreting prolactin. Kovacs et al. (1977) in an ul trastructural investigation of adenomas of old female Long-Evans rats, found that they were composed of prolactin cells. Berkvens et al. (1980) using immunocytochemistry at the light microscopic level, demonstrated that some spontaneous tumors of old Wistar rats could contain GH, TSH or ACTH as well as PRL.

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Silica Incorporation in the Cell Wall of the Singing Cell of Urtica dioica

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100116541 ◽

1975 ◽

Vol 33 ◽

pp. 584-585

Author(s):

A. E. Sowers ◽

E. L. Thurston

Keyword(s):

Cell Wall ◽

Unique Feature ◽

Urtica Dioica ◽

Wall Material ◽

Pain Response ◽

Apical Portion ◽

Ultrastructural Investigation ◽

Plant Families ◽

Bulbous Tip

Plant stinging emergences exhibit functional similarities in that they all elicit a pain response upon contact. A stinging emergence consists of an elongated stinging cell and a multicellular pedestal (Fig. 1). A recent ultrastructural investigation of these structures has revealed the ontogeny and morphology of the stinging cells differs in representative genera in the four plant families which possess such structures. A unique feature of the stinging cell of Urtica dioica is the presence of a siliceous cell wall in the apical portion of the cell. This rigid region of the cell wall is responsible for producing the needle-like apparatus which penetrates the skin. The stinging cell differentiates the apical bulbous tip early in development and the cell continues growth by intercalary addition of non-silicified wall material until maturity.The uppermost region of the stinging cell wall is entirely composed of silica (Fig. 2, 3) and upon etching with a 3% solution of HF (5 seconds), the silica is partially removed revealing the wall consisting of individualized silica bodies (Fig. 4, 5).

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Ultrastructural investigation of substance P-, leucine-enkephalin- and 5-hydroxytryptaminelike immunoreactive terminals in the area of cremaster motoneurons of the male rat

Neuroscience ◽

10.1016/0306-4522(89)90016-x ◽

1989 ◽

Vol 28 (3) ◽

pp. 711-723 ◽

Cited By ~ 11

Author(s):

B.-R. Wang ◽

E. Senba ◽

M. Tohyama

Keyword(s):

Substance P ◽

Male Rat ◽

Leucine Enkephalin ◽

Ultrastructural Investigation

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Gametogenesis and the reproductive cycle in the deep-sea anemone Paracalliactis stephensoni (Cnidaria: Actiniaria)

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400034287 ◽

1990 ◽

Vol 70 (1) ◽

pp. 163-172 ◽

Cited By ~ 13

Author(s):

Michel Praet-Van

Keyword(s):

Organic Matter ◽

Shallow Water ◽

Deep Sea ◽

Phytoplankton Bloom ◽

Sea Anemone ◽

Bay Of Biscay ◽

Sea Anemones ◽

Spring Phytoplankton Bloom ◽

Sea Floor ◽

Ultrastructural Investigation

This ultrastructural investigation of gametogenesis in a deep-sea anemone of the Bay of Biscay trawled around 2000 m depth, contributes to the knowledge of biology and strategy of reproduction of deep-sea benthos.This sea anemone is dioecious. The sperm appears very similar to those of shallow water sea anemones of the genus, Calliactis. The ultrastructural investigation of oogenesis allows the characteristics of the stages of previtellogenesis and vitellogenesis to be defined. The latter begins with a period of lipogenesis correlated with the formation of a trophonema. Mature oocytes measure up to 180 (im in diameter. Study of spermatogenesis and oogenesis reveals that spawning occurs in April/May. In males, the main area of testicular cysts, full of sperm, reaches maximal development from March to May and, in females, the percentage of mature oocytes decreases from 33% in April to 1% in May.Spawning may be induced by the advent in the deep-sea of the products of the spring phytoplankton bloom. This period of spawning, during the increased deposition of organic matter to the deep-sea floor, may be an advantageous strategy for early development of Paracalliactis.

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