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Full-Text Articles in Life Sciences

The Cytoskeletal System Of Nucleated Erythrocytes. I. Composition And Function Of Major Elements, William D. Cohen, Diana Bartelt, Richard Jaeger, George M. Langford, Iris Nemhauser Sep 2015

The Cytoskeletal System Of Nucleated Erythrocytes. I. Composition And Function Of Major Elements, William D. Cohen, Diana Bartelt, Richard Jaeger, George M. Langford, Iris Nemhauser

George M Langford

We have studied the dogfish erythrocyte cytoskeletal system, which consists of a marginal band of microtubules (MB) and trans-marginal band material (TBM). The TBM appeared in whole mounts as a rough irregular network and in thin sections as a surface-delimiting layer completely enclosing nucleus and MB. In cells incubated at 0 degrees C for 30 min or more, the MB disappeared but the TBM remained. MB reassembly occurred with rewarming, and was inhibited by colchicine. Flattened elliptical erythrocyte morphology was retained even when MBs were absent. Total solubilization of MB and TBM at low pH, or dissolution of whole anucleate ...


Comparative Vegetative Anatomy And Systematics Of Oncidiinae (Maxillarieae, Orchidaceae), William Louis Stern, Barbara S. Carlsward Jan 2006

Comparative Vegetative Anatomy And Systematics Of Oncidiinae (Maxillarieae, Orchidaceae), William Louis Stern, Barbara S. Carlsward

Barbara S. Carlsward

Subtribe Oncidiinae comprises a vegetatively heterogeneous assemblage of species that has persistently been incapable of organization. Anatomy was considered to be a possible means to resolve the perplexity of relationships amongst the constituent taxa. The consistent occurrence of a foliar hypodermis, homogeneous mesophyll, conical silica bodies in stegmata, and ubiquitous fibre bundles in leaves provides a matrix for linking the taxa, as do the parenchymatous pith and O-thickened endodermal cell walls in roots. However, the strict consensus of the 40 genera studied was completely unresolved, suggesting that vegetative characters alone are insufficient to assess the relationships amongst these taxa, a ...