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W J Lanzing

Publications and source records attributed to W J Lanzing.

6 recordsLinked to original sources
PubMed1982

The ultrastructure of the eye of the mosquitofish Gambusia affinis.

The ultrastructure of the tissue components of the eye of Gambusia affinis, excluding the sensory cells, is described. The cornea consists of two different sections of collagenous layers of different density. The choroid includes an argentea composed of alpha- and beta-melanophores, lipopterinophores and a choriocapillaris associated with the rete mirabile of the choroid body, Bruch's membrane, underlying the retinal pigment layer, can develop complex associations with fibroblasts delimiting the choriocapillaris. The outer section (stroma) of the iris includes several cell types that are not found in the inner or vitread section. In adult Gambusia the lens capsule is well developed, but in two-week-old Sarotherodon larvae the lens epithelium is covered only by a glycocalyx.

Animals↗
PubMed1976

The fine structure of fins and finrays of Tilapia mossambica (Peters).

Light and electron-microscopic studies were carried out on the fins of the fish Tilapia mossambica (Peters). A detailed description is presented of the different skeletal components comprising the finrays. The mode of development of the hemisegments appears in several ways similar to that of fish scales. Each hemisegment is contained by an envelope of scleroblasts which secrete collagen fibres in a unipolar fashion. Calcification takes place as a result of deposition of hydroxyapatite-like crystals between the collagen fibres. However, the orientation of these fibres is not as regular as that of the fibres occurring in scales.

Animals↗
PubMed1976

The ultrastructure and calcification of the scales of Tilapia mossambica (Peters).

The scales of Tilapia are surrounded by an envelope of scleroblasts responsible for the production of layers of collagen that constitute the bulk of the scale. The scleroblasts adjoining the lateral face of the oldest scale region gradually atrophy. New Collagen layers are deposited against the inner face of the scale, the adjoining scleroblasts showing evidence of high metabolic activity. Calcification occurs by inotropic deposition of crystals alongside the fibres. There is no sharp demarcation between calcified and non-calcified scale regions, a calcification front gradually moving towards newly formed collagen layers. It is felt that fish scales should be considered as calcified derivatives of dermal collagen layers.

Animals↗