Optical tweezers are widely used for the manipulation of cells and their internal structures. However, the degree of manipulation possible is limited by poor control over the orientation of trapped cells. We show that it is possible to controllably align or rotate disc shaped cells—chloroplasts of Spinacia oleracea—in a plane polarised Gaussian beam trap, using optical torques resulting predomi...

plant extracts, like phytoecdysteroids, are currently studied because of the possibility of their use in plant protection. phytoecdysteroids are insect steroid hormone analogues, and they are believed to deter invertebrates from plants, either by acting as antifeedants or by being toxic through hormonal disruption on ingestion. we describe here the effects of extract from spinacia oleracea l. (...

Intact chloroplasts of spinach (Spinacia oleracea L.), sunflower (Helianthus annuus L.), and maize (Zea mays L.) mesophyll cells contained 0.33, 0.50, and 0.14% of bound hexosamine on a protein basis, respectively. Undifferentiated maize chloroplasts contained 0.19%. Values for chloroplast lamellae were, respectively, 0.16, 0.18, 0.12, and 0.06% and for envelope membranes they were 1.6, 2.5, 3....

A procedure for isolating spinach (Spinacia oleracea L.) leaf peroxisomes in 0.25 molar sucrose solution by Percoll density gradient centrifugation followed by removal of the Percoll by washing and centrifugation was established. The preparation contains more than 90% peroxisomes as intact organelles with no detectable chlorophyll or cytochrome oxidase contamination. The peroxisomes are stable ...

Etiolated spinach (Spinacia oleracea L. var Winter Giant) seedlings show a residual photosynthetic fructose-1,6-bisphosphatase activity, which sharply rises under illumination. This increase in activity is due to a light-induced de novo synthesis, as it has been demonstrated by enzyme labeling experiments with (2)H(2)O and [(35)S]methionine. The rise of bisphosphatase activity under illuminatio...

It was previously reported that magnesium ion inhibited carbonic anhydrase (Bamberger and Avron 1975 Plant Physiol 56: 481-485). Studies with partially purified carbonic anhydrase from spinach (Spinacia oleracea L.) chloroplasts show that the effect was the result of the chloride counterion and not the magnesium ion. Enzyme activity was reduced 50% upon addition of 3 to 10 millimolar MgCl(2) or...

Choline acetyltransferase was demonstrated in nettles (Urtica dioica), peas (Pisum sativum), spinach (Spinacia oleracea), sunflower (Helianthus annuus) and blue--green algae by using a Sepharose--CoASH affinity column. The column effected a 1500-fold purification of the enzyme from nettle homogenates and was required for demonstrating activity in the other higher plants. Demonstration of the en...

Isolated envelope membranes of spinach chloroplasts (Spinacia oleracea L. var. Viroflay) exhibited selective permeability. Metabolites such as 3-phosphoglycerate, bicarbonate, glyoxylate, and acetate were transported rapidly; 6-phosphogluconate, glycolate, glycine, l-malate, and succinate were intermediate; whereas glucose 6-phosphate, fructose 1,6-diphosphate, and sucrose were hardly transport...

Treatment with Spinacia oleracea extract (SO; 400 mg/kg body weight) decreased the locomotor activity, grip strength, increased pentobarbitone induced sleeping time and also markedly altered pentylenetetrazole induced seizure status in Holtzman strain adult male albino rats. SO increased serotonin level and decreased both norepinephrine and dopamine levels in cerebral cortex, cerebellum, caudat...