Species-specific effect of macrobenthic assemblages on meiobenthos and nematode community structure in shallow sandy sediments

Mesodermal tissue from the chick embryo at various stages of early differentiation was cultured in hydrated gels of type I collagen in the presence and absence of transferrin. Primary mesoderm explants from primitive-streak-stage embryos responded to the presence of avian transferrin by significantly improved outgrowth which appeared to be related to the ability of the cells to attach to, and migrate in, the collagen. No evidence was obtained which suggested that this observation was dependent on increased cell proliferation. This outgrowth enhancement was not duplicated by transferrin of human origin. The avian transferrin did not produce this effect on cells cultured on plastic substrata, suggesting that the species-specific effect involves modulation by the extracellular matrix. Mesoderm explants from somite stages of development showed no increase in outgrowth in the presence of either avian or human transferrin as judged by counting the number of outwandering cells. Ultrastructural immunocytochemistry indicated surface binding of transferrin by cells in the gels, and the presence of endogenous transferrin on the surfaces of mesoderm cells in situ and in their extracellular environment. It is suggested that by binding to cell surface receptors, transferrin may be able to influence the strength of cellular adhesion to collagen and hence the capacity for cell locomotion.

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It Takes a Village: Entomopathogenic Nematode Community Structure and Conservation Biological Control in Florida (U.S.) Orchards

Nematode Pathogenesis of Insects and Other Pests ◽

10.1007/978-3-319-18266-7_13 ◽

2015 ◽

pp. 329-351 ◽

Cited By ~ 2

Author(s):

Raquel Campos-Herrera ◽

Fahiem E. El-Borai ◽

Larry W. Duncan

Keyword(s):

Biological Control ◽

Community Structure ◽

Entomopathogenic Nematode ◽

Conservation Biological Control ◽

Nematode Community

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Osteocalcin Production in Primary Osteoblast Cultures Derived from Normal and Hyp Mice

Endocrinology ◽

10.1210/endo.139.1.5677 ◽

1998 ◽

Vol 139 (1) ◽

pp. 35-43 ◽

Cited By ~ 29

Author(s):

Thomas O. Carpenter ◽

Kathleen C. Moltz ◽

Bruce Ellis ◽

Monica Andreoli ◽

Thomas L. McCarthy ◽

...

Keyword(s):

Messenger Rna ◽

Cultured Cells ◽

Primary Cultures ◽

Specific Effect ◽

Continuous Exposure ◽

Primary Osteoblast ◽

Characteristic Features ◽

Species Specific ◽

Osteocalcin Production

Abstract Rickets and osteomalacia are characteristic features of the Hyp mouse model of human X-linked hypophosphatemia. Hyp mice demonstrate elevated circulating osteocalcin levels, as well as altered regulation of osteocalcin by 1,25(OH)2D3. Whether this osteocalcin abnormality is intrinsic to the osteoblast, or mediated by the in vivo milieu, has not been established. We therefore characterized osteocalcin production and its regulation by 1,25(OH)2D3 in primary cultures of murine osteoblasts and examined osteocalcin and its messenger RNA in response to 1,25(OH)2D3 in cultures of Hyp mouse-derived osteoblasts. Cell viability and osteocalcin production are optimal when murine cells are harvested within 36 h of age. Murine primary osteoblast cultures mineralize and produce osteocalcin in a maturation-dependent fashion (as demonstrated in other species), and continuous exposure to 1,25(OH)2D3, beginning at day 9 of culture, inhibits osteoblast differentiation and osteocalcin production and prevents mineralization of the culture. However, in contrast to other species, exposure to 1,25(OH)2D3, added later (days 17–25) in culture, does not stimulate osteocalcin but arrests osteocalcin production at current levels. Ambient media levels of osteocalcin were no different in cultures from Hyp mice and their normal litter mates, and the down-regulatory response to 1,25(OH)2D3 was comparable in cultures from normal and Hyp mice. Furthermore, expression of osteocalcin messenger RNA in murine cultures is reduced with exposure to 1,25(OH)2D3, and there is no difference between normal and Hyp cultures in this response. Thus, primary murine osteoblasts manifest a species-specific effect of 1,25(OH)2D3 on osteocalcin production. Furthermore, the increased serum osteocalcin production seen in intact Hyp mice, and the altered response to 1,25(OH)2D3 in Hyp mice, are not observed in osteoblast cultures derived from the mutant strain. These data indicate that abnormalities of osteocalcin described in intact Hyp mice require factors other than those present in cultured cells.

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