The objectives of this study were (a): to define the effects of light, dark, and temperature on nodule activity (acetylene reduction), and (b) to establish the contributions of reserve carbohydrate and recent photosynthate to the support of nodule function. An in situ assay of nodule activity was developed for use with intact, hydroponically grown soybeans (Glycine max [L.] Merr. cv. Calland).N...

Rats were housed in either continuous lighting (LL), an extended photoperiod of 18 h light-6 h dark (LD 18:6) or a 12 h light-12 h dark (LD 12:12) lighting cycle. The effects of these various lighting regimens on the sensitivity of dorsal lateral geniculate neurones to iontophoresed noradrenaline and serotonin (5-HT) was examined. Exposure to either continuous lighting or to an extended photope...

Circadian rhythms are a fundamental property of most organisms, from cyanobacteria to humans. In the unicellular obligately photoautotrophic cyanobacterium Synechococcus elongatus PCC 7942, essentially all promoter activities are controlled by the KaiABC-based clock under continuous light conditions. When Synechococcus cells are transferred from the light to continuous dark (DD) conditions, the...

Positive phototaxis in cell populations of a phytoflagellate Cryptomonas sp. was recorded photoelectrically when the duration and intensity of repeated pulses of monochromatic yellow light (570 nm) interspersed with darkness were varied. Irrespective of the duration of the light pulses, phototactic responses to repeated pulses were as great as those to continuous irradiation and were linearly d...

We examined the changes in the levels of indoleacetic acid (IAA), IAA esters, and a 22-kilodalton subunit auxin-binding protein (ABP1) in apical mesocotyl tissue of maize (Zea mays L.) during continuous red light (R) irradiation. These changes were compared with the kinetics of R-induced growth inhibition in the same tissue. Upon the onset of continuous irradiation, growth decreased in a cont...

Artemisinin is a sesquiterpene lactone endoperoxide extracted from a traditional Chinese medicinal plant Artemisia annua. Artemisinin-based combination therapies (ACTs) are recommended as the best treatment of malaria by the World Health Organization (WHO). Both the phytohormone jasmonic acid (JA) and light promote artemisinin biosynthesis in A. annua. Interestingly, we found that the increase ...

Deposits of darkmaterial appear on Vesta’s surface as features of relatively low-albedo in the visible wavelength range of Dawn’s camera and spectrometer. Mixed with the regolith and partially excavated by younger impacts, the material is exposed as individual layered outcrops in crater walls or ejecta patches, having been uncovered and broken up by the impact. Dark fans on crater walls and dar...

Using microdialysis, we investigated the circadian rhythms of the extracellular concentrations of dopamine, glutamate and gamma-aminobutyric acid (GABA) in the striatum and nucleus accumbens of the awake rat. Wistar rats were maintained in a 12 hr dark:12 hr light (12:12) cycle for 2 wk before the experiment began. The neurotransmitter levels were measured every 30 min for 30 hr in control (mai...

Cone flicker threshold rises as the rods dark adapt, though the cone threshold to continuous light remains constant. The rise is normally about 1 log unit, but in certain patients who complain of night blindness it may be as great as 2.5 log units. In these persons the kinetics of the rod-cone interaction are those of the recovery of rod sensitivity. The rods impose a low-pass filter on the con...