The increasing knowledge of the significance of vitamin B₆ in
human metabolic processes has emphasized the importance of developing
reliable means of assessing nutritional status with respect to
this vitamin. One possible approach to this end is the measurement
of pyridoxal phosphate in blood or plasma, particularly since this
phosphorylated...
Iodoacetic acid and diphenylamine were used in this study to
elucidate the mechanisms of resistance of Micrococcus radiodurans
to radiation. This organism, a gram positive, non-spore forming,
salmon-pink, tetracoccus has a LD₅₀ of 213,000 R when grown in
the absence of radio-modifying agents.
M. radiodurans, when grown in media containing...
More than 2,000 male newts were collected during the summer
and maintained unfed at 10°C both pre- and post-irradiation.
Exposures ranging up to 30 kR were given with 300 kVp X-rays and
⁶⁰Co gamma rays. Half of the newts were injected (I. P.) with 15 g
DMSO/kg (the maximum sublethal...
The uptake, retention, and distribution of ⁶⁰Co, ⁶⁵Zn, ⁸⁵ Sr, and ¹³¹I was examined in the Rough-Skinned Newt (Taricha granulosa). Each of these radionuclides is a possible contaminant of the freshwater environment and, thus, is of importance in radioecology. The newts were maintained singly at 10° C in an unfed...
The use of radioactive isotopes as tracers in biological systems
has become widespread since the close of World War II. Proper
use of radiotracers requires a fundamental understanding of the physical
nature of radioactivity, the characteristics of ionizing radiation,
and the various methods available for measuring radioactivity.
More importantly, the...
Osmotic and ionic regulation was studied in the North
American crayfish Pacifastacus leniusculus (Dana), stepwise acclimated
to increasing salinities. Stepwise acclimation involved transferring
crayfish at 48 hour intervals from freshwater to 100% seawater
in 20% increments. In experiments where 70% seawater was
used, animals were moved directly from 40 to...