Transmitter exocytosis from the neuronal soma is evoked by brief trains of high frequency electrical activity and continues for several minutes. Here we studied how active vesicle transport towards the plasma membrane contributes to this slow phenomenon in serotonergic leech Retzius neurons, by combining electron microscopy, the kinetics of exocytosis obtained from FM1-43 dye fluorescence as ve...

Radix Isatidis (Isatis indigotica Fort.) is one of the most important traditional Chinese medicine plants. However, there is no suitable herbicide used for weed control in Radix Isatidis field during postemergence stage. To explore the safety of sulfonylurea herbicide nicosulfuron on Radix Isatidis (Isatis indigotica Fort.) seedlings and the photosynthetic physiological response of the plant to...

Leaves from spinach (Spinacia oleracea L. cv Hybrid 102) plants grown in Mn-deficient nutrient solution were characterized by chlorosis, lowered chlorophyll a/b ratio and reduced electron transport. There were characteristic changes in room temperature fluorescence induction kinetics with increased initial yield (F(o)) and decreased variable fluorescence (F(v)). The fluorescence yield after the...

We present a new simulation model of the reactions in the photosynthetic electron transport chain of C3 species. We show that including recent insights about the regulation of the thylakoid proton motive force, ATP/NADPH balancing mechanisms (cyclic and noncyclic alternative electron transport), and regulation of Rubisco activity leads to emergent behaviors that may affect the operation and reg...

Photosynthetic O(2) evolution and chlorophyll a fluorescence were measured in 1-year-old needles of unfertilized and fertilized trees of Norway spruce (Picea abies (L.) Karst.) during recovery of photosynthesis from winter inhibition in northern Sweden. Measurements were made under laboratory conditions at 20 degrees C. In general, the CO(2)-saturated rate of O(2) evolution was higher in needle...

To assess photosynthesis as a bioindicator of toxicity from polycyclic aromatic hydrocarbons (PAHs), the response of chlorophyll-a fluorescence to creosote exposure was compared with effects on population-level plant growth. Large, outdoor, freshwater microcosms containing Eurasian watermilfoil (Myriophyllum spicatum) received either a single application or multiple applications of liquid creos...

Nine diterpene lactone amide derivatives 1-9 were synthesized from 6-oxovouacapan-7beta,17beta-lactone, which was obtained from 6alpha,7beta-dihydroxyvouacapan-17beta-oic acid isolated from Pterodon polygalaeflorus Benth., and tested for their activity on photosynthetic electron transport. Amide derivatives 3-5 behaved as electron transport chain inhibitors; they inhibited the photophosphorylat...

We present the theoretical rationales for data analysis protocols that afford an efficient extraction of conformational dynamics on a broad range of time scales from single-molecule fluorescence lifetime trajectories. Based on correlation analyses, a photon-by-photon approach on one hand provides the highest time resolution, whereas a minimal-binning method on the other hand is most suitable fo...

Winter wheat (Triticum aestivum L. cv Norin No. 61) was grown at 25 degrees C until the third leaves reached about 10 cm in length and then at 15 degrees C, 25 degrees C, or 35 degrees C until full development of the third leaves (about 1 week at 25 degrees C, but 2-3 weeks at 15 degrees C or 35 degrees C). In the leaves developed at 15 degrees C, 25 degrees C, and 35 degrees C, the optimum tem...

Hydrogen photoproduction by eukaryotic microalgae results from a connection between the photosynthetic electron transport chain and a plastidial hydrogenase. Algal H₂ production is a transitory phenomenon under most natural conditions, often viewed as a safety valve protecting the photosynthetic electron transport chain from overreduction. From the colony screening of an insertion mutant librar...