Assessing the performance of sampling designs for measuring the abundance of understory plants.

Accurate estimation of responses of understory plants to disturbance is essential for understanding the efficacy of management activities. However, the ability to assess changes in the abundance of plants may be hampered by inappropriate sampling methodologies. Conventional methods for sampling understory plants may be precise for common species but may fail to adequately characterize abundance of less common species.

A ciliary neuronotrophic factor from peripheral nerve and smooth muscle which is not retrogradely transported.

We have found that a CNTF-like molecule which supports ciliary and sympathetic neurons is not retrogradely transported in either sympathetic or parasympathetic nerves. The factor has an apparent Mr of 21 kDa, a pI of 4.9, and is present in peripheral nerves and smooth muscle of the chick.

Endogenous chicken nerve growth factor from sheath cells is transported in regenerating nerve.

We report the presence of endogenous nerve growth factor (NGF) in chicken peripheral nerve. The molecule has been detected with antibodies to mouse salivary gland NGF, using immunohistochemical and immunoelectrophoretic techniques. Previous studies have shown that these antibodies inhibit the survival activity of extracts of chicken peripheral nerve.

Transport of endogenous nerve growth factor in the proximal stump of sectioned nerves.

Immunohistochemistry has been used to demonstrate the presence of nerve growth factor (NGF)-like immunoreactivity in normal and sectioned mouse sciatic nerves. In normal nerves, immunoreactive material was not visible unless a silk ligature had previously been applied to constrict the nerves, and only then in the segment of nerve immediately distal to the ligation. Immunoreactivity was visible as early as 2 h after application of the ligature.

Production and transport of endogenous trophic activity in a peripheral nerve following target removal.

High concentrations of trophic factor for sympathetic neurones were found in the discrete nerve which innervates the expansor secundariorum muscle of the chicken wing. Mouse nerve growth factor (NGF) was additive with nerve extract in allowing survival of sympathetic neurones. Antiserum to NGF, while inhibiting outgrowth in response to NGF, only partially blocked survival promoted by the nerve extract.