Separation of Protein Crystals from Spores of Bacillus thuringiensis by Ludox Gradient Centrifugation.

A method is described for the purification of Bacillus thuringiensis protein crystals by Ludox gradient centrifugation. This method is simple, inexpensive, fast, and efficient compared with other techniques. It has been successfully used to purify and characterize the protein crystals from several B.

The Kinetics of Chlorate Uptake by XD Tobacco Cells.

The uptake of [(36)Cl]chlorate by the 14U variant of the XD cell line of Nicotiana tobaccum L. cv Xanthi was investigated to examine the use of chlorate as a nitrate analog in transport studies. The kinetics of chlorate uptake against concentration was complex.

N-caffeoyl-4-amino-n-butyric acid, a new flower-specific metabolite in cultured tobacco cells and tobacco plants.

PUT cells were selected from the XD line of cultured tobacco cells (Nicotiana tabacum L. cv. Xanthi-nc) for the ability to utilize putrescine as sole nitrogen source.

Tubulin from cultured tobacco cells: isolation and identification based on similarities to brain tubulin.

The microtubule protein, tubulin, was isolated from most other proteins of cell suspension cultures of Nicotiana tabacum L. by its copolymerization with cow-brain tubulin. Cow-brain tubulin was added to the soluble protein fraction of extract from (35)S-labeled tobacco cells and subjected to two cycles of temperature-dependent assembly-disassembly (copolymerization).

Developmental changes in the potential for h(2)s emission in cucurbit plants.

Based on results obtained with leaf discs exposed to sulfate, leaves on cucurbit plants (Cucurbita pepo L. cv Small Sugar Pumpkin and Cucumis sativus cv Chipper) 1 to 2.5 weeks old have a low potential for H(2)S emission (less than 10 picomoles per min per cm(2) leaf area) in response to sulfate, whereas discs from most of the leaves on plants 3 to 4 weeks old emit H(2)S at a higher rate (50 to 150 picomoles per min per cm(2) leaf area).

Resistance to injury by sulfur dioxide : correlation with its reduction to, and emission of, hydrogen sulfide in Cucurbitaceae.

In Cucurbitaceae young leaves are resistant to injury from acute exposure to SO(2), whereas mature leaves are sensitive. After exposure of cucumber (Cucumis sativus L.) plants to SO(2) at injurious concentrations, illuminated leaves emit volatile sulfur, which is solely H(2)S.

Emission of Hydrogen Sulfide by Leaf Tissue in Response to l-Cysteine.

Leaf discs and detached leaves exposed to l-cysteine emitted a volatile sulfur compound which was proven by gas chromatography to be H(2)S. This phenomenon was demonstrated in all nine species tested (Cucumis sativus, Cucurbita pepo, Nicotiana tabacum, Coleus blumei, Beta vulgaris, Phaseolus vulgaris, Medicago sativa, Hordeum vulgare, and Gossypium hirsutum). The emission of volatile sulfur by cucumber leaves occurred in the dark at a similar rate to that in the light.

Evidence for an intracellular sulfur cycle in cucumber leaves.

H2S emission from cucumber (Cucumis sativus L.) leaf discs supplied with L-cysteine in the dark is inhibited 80-90% by aminooxyacetic acid (AOA), an inhibitor of pyridoxal-phosphate dependent enzymes. Exposure to L-cysteine in the light enhanced the emission of H2S in response to this sulfur source.

Stimulation of h(2)s emission from pumpkin leaves by inhibition of glutathione synthesis.

The effect of inhibitors of glutathione (GSH) synthesis, namely gamma-methyl glutamic acid, d-glutamic acid, cystamine, methionine-S-sulfoximine (MSX), buthionine-S-sulfoximine, and GSH itself, on the emission of H(2)S was investigated. All these compounds stimulated H(2)S emission from pumpkin (Cucurbita pepo L. cv Small Sugar Pumpkin) leaf discs in response to sulfate.

Association of Formation and Release of Cyclic AMP with Glucose Depletion and Onset of Chlorophyll Synthesis in Poterioochromonas malhamensis.

Depletion of glucose from the culture medium by Poterioochromonas malhamensis results in cessation of growth and accumulation of cyclic adenosine 3':5'-monophosphate (cAMP), followed by formation of chlorophyll and an increase in extracellular cAMP. Readdition of glucose to the culture medium causes P. malhamensis to release its intracellular cAMP into the medium.

Resistance to acetohydroxamate acquired by slow adaptive increases in urease in cultured tobacco cells.

Urease activity of tobacco XD cells (1U cells) had undergone a 4-fold increase (4U cells) during a year of growth on urea (Skokut and Filner 1980 Plant Phvsiol 65: 995-1003). A clone of 4U cells gave rise to 12U cells during another year of growth on urea. The doubling time of 12U cells on urea is 2.

The action of antimitotic herbicides on flagellar regeneration in Chlamydomonas reinhardtii: a comparison with the action of colchicine.

The effect of the antimitotic herbicides amiprophosmethyl, trifluralin, and oryzalin upon flagellar regeneration in Chlamydomonas reinhardtii has been studied. After flagellar amputation colchicine completely blocks its regeneration at 2.5 mM whereas the herbicides do so at 5 microM.

Slow adaptive changes in urease levels of tobacco cells cultured on urea and other nitrogen sources.

Tobacco (cv. Xanthi) XD cells cultured for more than a year on urea as the sole source of nitrogen have urease activities about four times higher than cells which have been cultured on nitrate. When cells which had always been grown on nitrate were transferred to urea, the urease activity in these cells remained at a lower level for eight transfers (40 generations), then gradually increased 4-fold during the next seven to 10 transfers.

Synthesis and Release of Cyclic Adenosine 3':5'-Monophosphate by Ochromonas malhamensis.

The chrysophycean alga, Ochromonas malhamensis Pringsheim, was shown to synthesize cyclic adenosine 3':5'-monophosphate (cAMP) and to release it into the culture medium. Cells contained 3 to 3,000 picomoles per gram fresh weight; medium contained up to 20 times the amount in the cells. Putative [(32)P]cAMP was purified from cultures supplied [(32)P]phosphate.

Emission of ethylene and ethane by leaf tissue exposed to injurious concentrations of sulfur dioxide or bisulfite ion.

Leaf tissues injured with SO(2) gas or bisulfite ion in solution emit ethylene and ethane. The amounts of these gases produced by the tissues depend on the degree of exposure to SO(2) or bisulfite. The amount of ethylene produced in response to SO(2) fumigation correlates positively with SO(2) exposure (0 to 5.

Mechanisms of resistance to sulfur dioxide in the Cucurbitaceae.

The relative resistance of four cultivars of the Cucurbitaceae (Cucumis sativus L. cv. National Pickling, and inbred line SC 25; Cucurbita pepo L.

Participation of calcium in flagellar shortening and regeneration in Chlamydomonas reinhardii.

Cation chelators cause flagellar shortening in Chlamydomonas reinhardii. Most effective are EDTA and EGTA (1 mM) but pyrophosphate (10 mM) also is effective. Addition of 5 mM Ca2+ after shortening caused by 4 mM EGTA results in flagellar regeneration.

Light-dependent Emission of Hydrogen Sulfide from Plants.

With the aid of a sulfur-specific flame photometric detector, an emission of volatile sulfur was detected from leaves of cucumber (Cucumis sativus L.), squash and pumpkin (Cucurbita pepo L.), cantaloupe (Cucumis melo L.

Specific inhibition of phototropism in corn seedlings.

Geotropism was used as a control for the specificity of potential inhibitors of phototropism by the coleoptiles of corn (Zea mays) seedlings. The compounds tested fall into three categories showing: (a) no inhibition of either phototropism or geotropism (KCl); (b) nonspecific inhibition of both phototropism and geotropism (KCN); and (c) specific inhibition of phototropism (KI, NaN(3), and phenylacetic acid). Simultaneous irradiation of coleoptiles with phototropically inert light in addition to the phototropically active blue light also results in an inhibition of phototropism.

Regulation of adenosine triphosphate sulfurylase in cultured tobacco cells. Effects of sulfur and nitrogen sources on the formation and decay of the enzyme.

The ATP sulfurylase of cultured tobacco cells is repressed during growth on readily assimiliated sulfur sources, such as sulfate, L-cysteine, or L-methionine, but it is derepressed during growth on slowly assimiliated sulfur sources, such as L-djenkolate or glutathione, or during sulfur starvation. The enzyme is not induced by sulfate. The enzyme level in the cells begins to rise 12 to 24 h after the derepression conditions are initiated and continues to rise for 3 to 4 days, up to as much as 25 times above the initial specific activity.

Adenosine 3':5'-Cyclic Monophosphate in Chlamydomonas reinhardtii: Isolation and Characterization.

Chlamydomonas reinhardtii contains a factor that can replace adenosine 3':5'-cyclic monophosphate (cAMP) in the stimulation of rabbit-muscle protein kinase. The factor cochromatographs and coelectrophoreses with authentic cAMP, and is inactivated by beef heart cyclic nucleotide phosphodiesterase. When C.

Anaerobic nitrite production by plant cells and tissues: evidence for two nitrate pools.

Tobacco (Nicotiana tabacum L. cv. Xanthi) XD cells containing nitrate and nitrate reductase stopped producing nitrite after approximately 1 hour when incubated under anaerobic conditions.

Adenosine 3',5'-cyclic monophosphate in Chlamydomonas reinhardtii. Influence on flagellar function and regeneration.

Adenosine 3',5'-cyclic monophosphate (cAMP) influences both flagellar function and flagellar regeneration in Chlamydomonas reinhardtii. The methylxanthine, aminophylline, which can cause a tenfold increase in cAMP level in C. reinhardtii, inhibits flagellar movement and flagellar regeneration by wild-type cells, without inhibiting cell multiplication.