Cut fibers (striation spacing, 3.6-4.2 microns) were mounted in a double Vaseline-gap chamber and studied at 14-15 degrees C. One or both of the Ca indicators fura-2 and purpurate-3,3' diacetic acid (PDAA) were introduced into the optical recording site by diffusion from the end pools. Sarcoplasmic reticulum (SR) Ca release was elicited by action potential stimulation. With resting [fura-2] = 0...

Spontaneous release of neurotransmitter has been demonstrated in various types of synapses. Its physiological significance, however, is still unknown. In nerve-muscle cultures of embryonic Xenopus laevis, we observed that acetylcholine, which is released spontaneously at the synaptic terminal, caused frequent twitches of muscle cells. These muscle cells developed cross-striations earlier than n...

Ox muscle in rigor mortis offers a selection of myofibrils fixed at varying degrees of contraction from sarcomere lengths of 3.7 to 0.7 micro. A study of this material by phase contrast and electron microscopy has revealed four distinct successive patterns of contraction, including besides the familiar relaxed and contracture patterns, two intermediate types (2.4 to 1.9 micro, 1.8 to 1.5 micro)...

Using transmission electron microscopy, we examined the body cuticle ultrastructures of phoretic and parasitic stages of the parasitaphelenchid nematodes Bursaphelenchus xylophilus, B. conicaudatus, B. luxuriosae, B. rainulfi; an unidentified Bursaphelenchus species, and an unidentified Parasitaphelenchus species. Nematode body cuticles usually consist of three zones, a cortical zone, a median ...

In February 2009, the National Academy of Sciences published a report entitled "Strengthening Forensic Science in the United States: A Path Forward." The report notes research studies must be performed to "…understand the reliability and repeatability…" of comparison methods commonly used in forensic science. Numerical classification methods have the ability to assign objective quantitative mea...

The amplitude, origin, and direction of striations in the subtropical gyre are investigated using simulated and analytical multidimensional spectra. Striations, defined as banded structures in the low-frequency motions, account for a noticeable percentage of zonal velocity variability in the east North Pacific (ENP: 258– 428N, 1508–1308W) and central North Pacific (CNP: 108–228N, 1328E–1628W) r...