Fine structure of the external egg membrane of five species of Pacific salmon and steelhead trout

Fine structure of the external egg membrane of five species of Pacific salmon (sockeye, Oncorhynchus nerka; pink, O. gorbuscha; chum, O. keta; coho, O. kisutch; and chinook, O. tshawytscha) and the anadromous steelhead trout (Salmo gairdneri), is examined and compared using the scanning electron microscope. Membrane thickness in fixed material varies for the six species as follows (micrometres, [Formula: see text]): sockeye, 34.15 ± 0.15; pink, 61.64 ± 1.53; chum, 53.05 ± 0.33; coho, 27.96 ± 0.48; chinook, 50.82 ± 0.74; steelhead, 30.74 ± 0.11. The membrane consists of a thin outermost layer, the externus, 0.2–0.3 μm thick, and the internus, 24–55 μm thick, which constitutes the remainder of the membrane. In sockeye, pink, and chum salmon and steelhead trout, an additional layer 3–8 μm thick, the "subinternus," occurs beneath the internus. The entire membrane appears fibrous except for the thin and apparently solid externus. Pores in both the inner and outer surfaces are arranged in a hexagonal pattern and are connected by pore canals traversing the membrane. Except in the sockeye, plugs commonly were seen blocking the external openings of the pore canals. Significance of the egg membrane fine structure is considered in relation to several of its roles in the water-activated egg: semipermeability, retention of internal pressure, and mechanical protection. A structural and functional analogy is drawn between the fine structure of the salmonid egg membrane and the mammalian aorta.

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Kudoa thyrsites (Gilchrist, 1924) (Myxozoa) in the cardiac muscle of Pacific salmon (Oncorhynchus spp.) and steelhead trout (Salmo gairdneri)

Canadian Journal of Zoology ◽

10.1139/z89-050 ◽

1989 ◽

Vol 67 (2) ◽

pp. 341-342 ◽

Cited By ~ 18

Author(s):

Z. Kabata ◽

D. J. Whitaker

Keyword(s):

British Columbia ◽

Cardiac Muscle ◽

Pacific Salmon ◽

Oncorhynchus Nerka ◽

Salmo Gairdneri ◽

Oncorhynchus Keta ◽

Steelhead Trout ◽

Myxozoan Parasite ◽

Kudoa Thyrsites ◽

Pacific Salmonids

An examination of the cardiac muscle of returning adults of all species of British Columbia Pacific salmonids, including steelhead trout (Salmo gairdneri), for infection by the myxozoan parasite Kudoa thyrsites showed that all species but chum (Oncorhynchus keta) and sockeye (Oncorhynchus nerka) are susceptible to infection. The prevalence of observed infection was low. Its intensity was not determined, but the small numbers of spores observed suggest that it was low. The possible causes of these observations are discussed.

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Influence of Size Upon the Adaptation of Steelhead Trout (Salmo gairdneri) and Chum Salmon (Oncorhynchus keta) to Sea Water

Journal of the Fisheries Research Board of Canada ◽

10.1139/f61-036 ◽

1961 ◽

Vol 18 (3) ◽

pp. 401-415 ◽

Cited By ~ 34

Author(s):

Arthur H. Houston

Keyword(s):

Chum Salmon ◽

Sea Water ◽

Water Salinity ◽

Salmo Gairdneri ◽

Oncorhynchus Keta ◽

Electrolyte Balance ◽

Steelhead Trout ◽

Chum Salmon Oncorhynchus Keta ◽

Salmonid Species ◽

Juvenile Chum Salmon

Steelhead trout in the smolt phase of development adapted to sea water (salinity 22–24 parts per thousand) more rapidly and with less extensive departures from regulated conditions of water–electrolyte balance than did the larger post-smolts. By contrast, the extent and duration of the corresponding changes accompanying adaptation of juvenile chum salmon to sea water varied inversely with size. The data are discussed in relation to the distinction between smolting and non-smolting salmonid species.

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Comparison of mechanical shock sensitivity of eggs of five Pacific salmon (Oncorhynchus) species and steelhead trout (Salmo gairdneri)

Aquaculture ◽

10.1016/0044-8486(89)90030-6 ◽

1989 ◽

Vol 78 (2) ◽

pp. 163-181 ◽

Cited By ~ 43

Author(s):

J.O.T Jensen ◽

D.F Alderdice

Keyword(s):

Pacific Salmon ◽

Salmo Gairdneri ◽

Mechanical Shock ◽

Steelhead Trout ◽

Shock Sensitivity

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The Dermal Glands of Rhodnius Prolixus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063202 ◽

1969 ◽

Vol 27 ◽

pp. 258-259

Author(s):

J. E. Lai-Fook

Keyword(s):

Fine Structure ◽

Secretory Activity ◽

Rhodnius Prolixus ◽

Outermost Layer ◽

Cement Layer ◽

Dermal Glands

Dermal glands are epidermal derivatives which are reported to secrete either the cement layer, which is the outermost layer of the epicuticle or some component of the moulting fluid which digests the endocuticle. The secretions do not show well-defined staining reactions and therefore they have not been positively identified. This has contributed to another difficulty, namely, that of determining the time of secretory activity. This description of the fine structure of the developing glands in Rhodnius was undertaken to determine the time of activity, with a view to investigating their function.

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The regulation of day–night changes in hydroxyindole-O-methyltransferase activity in the pineal gland of steelhead trout (Salmo gairdneri)

Canadian Journal of Zoology ◽

10.1139/z76-175 ◽

1976 ◽

Vol 54 (9) ◽

pp. 1530-1534 ◽

Cited By ~ 30

Author(s):

John R. Smith ◽

Lavern J. Weber

Keyword(s):

Pineal Gland ◽

Sharp Increase ◽

Pineal Region ◽

Salmo Gairdneri ◽

Steelhead Trout ◽

Methyltransferase Activity ◽

Surgical Exposure

Elevation in pineal hydroxyindole-O-methyltransferase (HIOMT; EC 2.1.1.4) activity in juvenile steelhead trout was associated with the dark portions of three different photoperiods with a sharp increase in pineal HIOMT activity occurring in the first 4 h of darkness. This pattern of activity could be abolished by bilateral enucleation but not by surgical capping of the pineal region. Surgical exposure of the pineal region in blinded fish did not restore HIOMT responses to changes in lighting.

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THE IN VITRO CULTIVATION OF TISSUE AND CELLS OF PACIFIC SALMON AND STEELHEAD TROUT*

Annals of the New York Academy of Sciences ◽

10.1111/j.1749-6632.1965.tb14303.x ◽

2006 ◽

Vol 126 (1) ◽

pp. 566-586 ◽

Cited By ~ 82

Author(s):

John L. Fryer ◽

Alexander Yusha ◽

K. S. Pilcher

Keyword(s):

Pacific Salmon ◽

In Vitro Cultivation ◽

Steelhead Trout

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Histopathology of the A1 Pulley in Adult Trigger Fingers

Journal of Hand Surgery (European Volume) ◽

10.1016/j.jhse.2007.06.002 ◽

2007 ◽

Vol 32 (5) ◽

pp. 556-559 ◽

Cited By ~ 43

Author(s):

M. C. SBERNARDORI ◽

P. BANDIERA

Keyword(s):

Connective Tissue ◽

Middle Layer ◽

Laminar Structure ◽

Loose Connective Tissue ◽

Control Series ◽

Outermost Layer ◽

Additional Layer ◽

Transmission Electron ◽

Electron Microscopes ◽

A1 Pulley

The histopathology of the central parts of 40 A1 pulleys from adult patients with primary trigger fingers was studied using light and transmission electron microscopes and the findings were compared with those in a control series of 10 normal A1 pulleys. The evaluation of the normal A1 pulley revealed a bi-laminar structure. The deepest layer was composed of dense normal connective tissue. The outermost layer was formed by loose connective tissue. In trigger digits, it was possible to identify a tri-laminar structure. The deepest layer was composed of irregular connective tissue, formed by small collagen fibres and abundant extracellular matrix. A considerable amount of chondroid-metaplasia was present in this layer. The middle layer contained dense, normal connective tissue with some fibrocytes. The outermost layer was formed of loose connective tissue. In conclusion, there was an additional layer in the A1 pulley in pathological cases which was not present in normal pulleys.

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