Inhibition of chlorophyll synthesis in Lemna minor by nalidixic acid

1975 ◽  
Vol 53 (20) ◽  
pp. 2319-2324 ◽  
Author(s):  
Hugh Frick ◽  
Raymond F. Jones
Keyword(s):  
Nalidixic Acid ◽  
Normal Individual ◽  
Lemna Minor ◽  
Chlorophyll Synthesis ◽  
Heterotrophic Growth ◽  
Free Medium ◽  
Mesophyll Cells ◽  
Normal Cells ◽  
Dense Cytoplasm ◽  
Rates Of Growth

Nalidixic acid bleached Lemna minor during growth in white light on a medium supporting heterotrophic growth. Immature, vacuolate mesophyll cells from bleached tissue contained plastids with aberrant thylakoids and had less-electron-dense cytoplasm than normal cells. Mitochondrial shape appeared normal. Individual bleached plants regreened and regained normal rates of growth after transfer to nalidixic-acid- (NAL-) free medium. Frond multiplication was also inhibited by NAL during growth in darkness. Purine and pyrimidine ribonucleosides did not prevent NAL-induced bleaching or growth inhibition.

AMINO ACID TRANSPORT IN YEAST AND EFFECTS OF NYSTATIN

1963 ◽  
Vol 41 (1) ◽  
pp. 397-407 ◽  
Author(s):  
E. Stachiewicz ◽  
J. H. Quastel
Keyword(s):  
Fatty Acids ◽  
Amino Acid ◽  
Calcium Ions ◽  
Amino Acid Transport ◽  
Protective Action ◽  
Yeast Cells ◽  
Acid Transport ◽  
Free Medium ◽  
Complete Protection ◽  
Normal Cells

Nystatin, an antifungal antibiotic, inhibits the accumulation, by yeast cells, of glycine, leucine, arginine, and alanine at concentrations that have no effect on the respiration of the cells. The uptake of glycine by yeast cells that have been preincubated with nystatin and then suspended in a nystatin-free medium is much lower than that of normal cells. The longer the preincubation with nystatin, the greater is the inhibition of glycine uptake. Nystatin produces two distinct effects. At concentrations below 0.8 μg/ml, nystatin inhibits glycine or arginine uptake. At concentrations from 0.8 to 2.0 μg/ml, it causes an efflux of previously accumulated glycine or arginine. Fatty acids, such as oleic, linoleic, stearic, or palmitic acid, can protect the yeast cell from the action of nystatin. The presence of citrate or versene abolishes the protective action of these fatty acids. Calcium ions also protect the cell from the action of nystatin. The concentration of calcium ions giving complete protection depends upon the nystatin concentration. The implications of these facts on amino acid transport in yeast are discussed.

Ultrastructure of organic acid secreting trichomes of chickpea (Cicer arietinum)

1989 ◽  
Vol 67 (9) ◽  
pp. 2669-2677 ◽  
Author(s):  
Mark D. Lazzaro ◽  
William W. Thomson
Keyword(s):  
Endoplasmic Reticulum ◽  
Granular Material ◽  
Organic Acid ◽  
Cicer Arietinum ◽  
Basal Cell ◽  
Fixed Carbon ◽  
Mesophyll Cells ◽  
Dense Cytoplasm ◽  
Acid Secreting ◽  
Organic Acid Secretion

The acid-secreting trichomes of chickpea (Cicer arietinum L.) were composed of 18 cells, including 1 basal cell, 3 elongate stalk cells, and 14 head cells. A subcuticular secretion chamber with cuticular pores was present above the head cells at the trichome tip. The basal and stalk cells had large central vacuoles, endoplasmic reticulum, mitochondria, and small vacuoles. In the stalk cells, these small vacuoles were aligned along microtubles extending from the bottom to the top of the cells. Head cells had more dense cytoplasm than stalk cells and also had numerous mitochondria and small vacuoles. A labyrinth of tubules and vesicles at the edges of the head cells contained granular material similar to that observed in the extraplasmic space of the head cell and in the secretion chamber. In older head cells, the tubules were thinner and lacked granular material, the cells contained sequestering membranes and vacuoles, and calcium oxalate crystals were observed in the extraplasmic space. Plasmodesmata were not observed between the basal cell and the surrounding mesophyll cells, although numerous plasmodesmata with associated desmotubules and endoplasmic reticulum connected the trichome cells. Chloroplasts were not observed in the head or stalk cells, whereas the basal cell had small chloroplasts with reduced thylakoid networks and the mesophyll cells had large chloroplasts with well-developed thylakoids that may provide the fixed carbon for organic-acid secretion.

scholarly journals The effect of gabaculine on tetrapyrrole biosynthesis and heterotrophic growth in Cyanidium caldarium

1988 ◽  
Vol 254 (3) ◽  
pp. 907-910 ◽  
Author(s):  
J D Houghton ◽  
L Turner ◽  
S B Brown
Keyword(s):  
Chlorophyll Synthesis ◽  
Similar Rate ◽  
Red Alga ◽  
Heterotrophic Growth ◽  
Tetrapyrrole Biosynthesis ◽  
Cyanidium Caldarium ◽  
Pigment Synthesis ◽  
Subsequent Exposure ◽  
Light Inhibition ◽  
Lag Period

Pigment synthesis in four strains of the unicellular red alga Cyanidium caldarium with different pigment-synthesizing patterns was inhibited in the presence of gabaculine (3-amino-2,3-dihydrobenzoic acid). Parallel inhibition of light-induced chlorophyll and phycocyanin synthesis was observed in strain III-D-2, which only synthesizes pigments in the light. Similar parallel inhibition was observed in the dark in mutant CPD, which is able to synthesize chlorophyll and phycocyanin in the absence of light. Inhibition of pigment synthesis in all strains was overcome by addition of 5-aminolaevulinic acid. Inhibition of phycocyanin synthesis in mutant GGB (unable to synthesize chlorophyll) and inhibition of chlorophyll synthesis in mutant III-C (unable to synthesize phycocyanin) were also observed. Gabaculine also inhibited the heterotrophic growth of C. caldarium in the dark. However, inhibition was overcome after an extended lag period, following which cell growth proceeded at a similar rate to that of control cells not exposed to gabaculine. Heterotrophic growth in cells pre-exposed to gabaculine was not inhibited by subsequent exposure. Possible mechanisms for this adaptation are discussed.

AMINO ACID TRANSPORT IN YEAST AND EFFECTS OF NYSTATIN

1963 ◽  
Vol 41 (2) ◽  
pp. 397-407 ◽  
Author(s):  
E. Stachiewicz ◽  
J. H. Quastel
Keyword(s):  
Fatty Acids ◽  
Amino Acid ◽  
Calcium Ions ◽  
Amino Acid Transport ◽  
Protective Action ◽  
Yeast Cells ◽  
Acid Transport ◽  
Free Medium ◽  
Complete Protection ◽  
Normal Cells

Nystatin, an antifungal antibiotic, inhibits the accumulation, by yeast cells, of glycine, leucine, arginine, and alanine at concentrations that have no effect on the respiration of the cells. The uptake of glycine by yeast cells that have been preincubated with nystatin and then suspended in a nystatin-free medium is much lower than that of normal cells. The longer the preincubation with nystatin, the greater is the inhibition of glycine uptake. Nystatin produces two distinct effects. At concentrations below 0.8 μg/ml, nystatin inhibits glycine or arginine uptake. At concentrations from 0.8 to 2.0 μg/ml, it causes an efflux of previously accumulated glycine or arginine. Fatty acids, such as oleic, linoleic, stearic, or palmitic acid, can protect the yeast cell from the action of nystatin. The presence of citrate or versene abolishes the protective action of these fatty acids. Calcium ions also protect the cell from the action of nystatin. The concentration of calcium ions giving complete protection depends upon the nystatin concentration. The implications of these facts on amino acid transport in yeast are discussed.

Effets physiologiques de l'atrazine à doses sublétales sur Lemna minor. V. Influence sur l'ultrastructure des chloroplastes

1980 ◽  
Vol 58 (14) ◽  
pp. 1571-1577 ◽  
Author(s):  
G. Beaumont ◽  
A. Lord ◽  
G. Grenier
Keyword(s):  
Lemna Minor ◽  
Sublethal Concentration ◽  
Ultrastructural Changes ◽  
Dense Network ◽  
Mesophyll Cells ◽  
Mineral Solution

A sublethal concentration of 0.25 ppm of atrazine produced many ultrastructural changes on the chloroplasts of mesophyll cells of Lemna minor L., cultivated aseptically in a mineral solution. The number of grana per chloroplast increased, whereas the intralamellar vesicles disappeared and outgrowths formed at the ends of chloroplasts. The grana of treated chloroplasts showed a reduction in the number of lamellae and formed a very dense network. The stroma of the same chloroplasts was reduced and accumulated osmiophilic globules.

scholarly journals Transcriptomic Analyses Reveal Leaf Colour Changes and L-theanine Accumulation in Variegated Tea

2021 ◽  
Author(s):  
Nianci Xie ◽  
Chenyu Zhang ◽  
Pinqian Zhou ◽  
Xizhi Gao ◽  
Shuanghong Tian ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Chlorophyll Biosynthesis ◽  
Colour Change ◽  
Amino Acid Content ◽  
Chlorophyll Synthesis ◽  
Chloroplast Biogenesis ◽  
Mesophyll Cells ◽  
Chlorophyll Metabolism ◽  
Leaf Colour ◽  
Depth Study

Abstract Background Camellia sinensis ‘Yanlinghuayecha’ (YHC) is a variegated mutant developed recently in China. To dissect the physiological and molecular mechanisms of leaf variegation, we compared the leaf pigmentation, cellular ultrastructure, amino acid content, and transcriptome between the albino (A), mosaic (M), and green (G) sectors.Results The contents of photosynthetic pigments were significantly lower in sector A and higher in sector G than in sector M. Chloroplasts with well-organized thylakoids were found only in the mesophyll cells of the G sector but not in those of the A sector. The A sector had a significantly higher content of total and free amino acids. In particular, the levels of theanine, glutamate, and alanine in the A sector were higher than those in the G sector. Transcriptomics analysis showed that a total of 44,908 unique transcripts were identified. Comparing the differentially expressed genes (DEGs) in the three sectors, we conducted an in-depth study on chloroplast biogenesis, chlorophyll biosynthesis, and theanine synthesis pathways. The expression of CsPPOX in “porphyrin and chlorophyll metabolism” was significantly downregulated in the A sector. CsLHCB6 in “Photosynthesis - antenna proteins” and CsSCY1 in “Protein processing in endoplasmic reticulum”, both of which were associated with chloroplast biogenesis, were significantly downregulated in the A sector. The expression of CsTS1 was notably upregulated in the A sector.Conclusion Taken together, variegation alters the gene activities involved in chloroplast biogenesis, and our results suggest that leaf colour change in the A sector incorporates three aspects compared with that in the G sector: (1) Decreased CsPPOX expression slows the rate of chlorophyll synthesis, resulting in a decrease in chlorophyll content; (2) downregulated expression of CsLHCB6 and CsSCY1 inhibits chloroplast biogenesis, decreasing thylakoid morphogenesis and grana stacking; and (3) the metabolic flow of glutamate changes, possibly from chlorophyll biosynthesis to theanine biosynthesis. The accumulation of precursor synthetic substances and the high expression of CsTS1 generates a high theanine content. These analyses provide valuable insights into variegation in tea plants with regard to leaf colour change and L-theanine accumulation.

Ultrastructural observations of soybean leaves affected by bacterial toxemia

1972 ◽  
Vol 50 (3) ◽  
pp. 529-531 ◽  
Author(s):  
J. Dueck ◽  
R. J. Zeyen ◽  
B. W. Kennedy
Keyword(s):  
Leaf Tissue ◽  
Mesophyll Cell ◽  
Ultrastructural Level ◽  
Cell Maturation ◽  
Starch Accumulation ◽  
Mesophyll Cells ◽  
Dense Cytoplasm ◽  
Leaf Mesophyll ◽  
Main Effect ◽  
Soybean Leaves

Soybean mesophyll cells from stunted and chlorotic trifoliolate leaf tissue affected by bacterial (Pseudomonas glycinea Coerper) induced toxemia, had dense cytoplasm, little vacuolation, chloroplasts with few lamellae, and little starch accumulation. Toxemia-affected cells exhibited no ultrastructural disruptions and resembled very young, healthy mesophyll cells. The main effect of the toxin appears to be a delay in mesophyll cell maturation rather than disruption at the ultrastructural level. Leaf mesophyll cells which had recovered from the bacterial toxemia appeared similar ultrastructurally to mature healthy cells, although they remained smaller.

Fusion of rapeseed and soybean protoplasts and subsequent division of heterokaryocytes

1974 ◽  
Vol 52 (11) ◽  
pp. 2435-2436 ◽  
Author(s):  
K. K. Kartha ◽  
O. L. Gamborg ◽  
F. Constabel ◽  
K. N. Kao
Keyword(s):  
Glycine Max ◽  
Polyethylene Glycol ◽  
Brassica Napus ◽  
Cell Cultures ◽  
Total Population ◽  
Brassica Napus L ◽  
Mesophyll Cells ◽  
Dense Cytoplasm ◽  
Glycine Max L ◽  
Fusion Products

Protoplasts from mesophyll cells of rapeseed plants (Brassica napus L. cv. Zephyr) and cell cultures of soybean (Glycine max (L.) Merr. cv. Mandarin) were induced to fuse and form heterokaryons by using polyethylene glycol. Plastids served as markers to identify heteroplasmic fusion products: the heterokaryons shared the chloroplasts from rapeseed and dense cytoplasm and colorless plastids from the soybean protoplasts. About 19–20% of the total population of viable protoplasts were identified as heterokaryons, some of which divided and formed colonies consisting of up to 10 cells within 10–12 days of culturing.

H2O2: a mediator of esophagitis-induced damage to calcium-release mechanisms in cat lower esophageal sphincter

2005 ◽  
Vol 288 (6) ◽  
pp. G1170-G1178 ◽  
Author(s):  
Weibiao Cao ◽  
Karen M. Harnett ◽  
Ling Cheng ◽  
Michael T. Kirber ◽  
Jose Behar ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Lower Esophageal Sphincter ◽  
Calcium Release ◽  
Circular Muscle ◽  
Activity Measurement ◽  
Free Medium ◽  
High Concentration ◽  
Normal Cells ◽  
Intracellular Ca ◽  
Esophageal Sphincter

We previously reported that induction of acute experimental esophagitis by repeated perfusion of HCl may affect release of intracellular Ca2+ stores. We therefore measured cytosolic Ca2+ in response to a maximally effective dose of ACh in fura 2-AM-loaded lower esophageal sphincter (LES) circular muscle cells and examined the contribution of H2O2 to the reduction in Ca2+ signal. In normal cells, the ACh-induced Ca2+ increase was the same in normal-Ca2+ and Ca2+-free medium and was abolished by the phosphatidylinositol 4,5-bisphosphate-specific phospholipase C inhibitor U-73122, confirming that the initial ACh-induced contraction depends on Ca2+ release from intracellular stores through production of inositol trisphosphate. In LES cells, the ACh-induced Ca2+ increase in normal-Ca2+ medium was significantly lower in esophagitis than in normal cells and was further reduced (∼70%) when the cells were incubated in Ca2+-free medium. This reduction was partially reversed by the H2O2 scavenger catalase. H2O2 measurements in LES circular muscle showed significantly higher levels in esophagitis than in normal cells. When normal LES cells were incubated with H2O2, the ACh-induced Ca2+ increase was significantly reduced in normal-Ca2+ and Ca2+-free medium and was similar to that observed in animals with esophagitis. The initial ACh-induced contraction was also reduced in normal cells incubated with H2O2. H2O2, when applied to cells at sufficiently high concentration, produced a visible and prolonged Ca2+ signal in normal cells. H2O2-induced cell contraction was also sensitive to depletion of stores by thapsigargin (TG); conversely, H2O2 reduced TG-induced contraction, suggesting that TG and H2O2 may operate through similar mechanisms. Ca2+-ATPase activity measurement indicates that H2O2 and TG reduced Ca2+-ATPase activity, confirming similarity of mechanism of action. We conclude that H2O2 may be at least partly responsible for impairment of Ca2+ release in acute experimental esophagitis by inhibiting Ca2+ uptake and refilling Ca2+ stores.

Anatomical changes induced by triazoles in wheat seedlings

1988 ◽  
Vol 66 (6) ◽  
pp. 1178-1185 ◽  
Author(s):  
J. Gao ◽  
G. Hofstra ◽  
R. A. Fletcher
Keyword(s):  
Triticum Aestivum L ◽  
Chlorophyll Synthesis ◽  
Epidermal Cells ◽  
Vascular Bundles ◽  
Mesophyll Cells ◽  
Wheat Seedlings ◽  
Anatomical Changes ◽  
Subsidiary Cells ◽  
Wheat Leaves ◽  
Stimulation Of

The triazoles triadimefon and S-3307, applied as seed treatments at two concentrations each (0.1 and 1.0, and 0.001 and 0.01 g active ingredient/kg of seed, respectively), increased epicuticular wax and reduced the length but increased the width and thickness of wheat leaves (Triticum aestivum L. cv. Glenlea). Mesophyll cells of treated leaves were thicker than those of controls and there were more layers of cells around the median and lateral vascular bundles of leaves treated with the higher concentration of S-3307. The length of epidermal cells was reduced and the width was increased by both triazoles; the depth of epidermal cells was increased by the higher concentration of triadimefon only. S-3307 increased the number of vascular bundles, whereas triadimefon at the higher concentration increased their diameter. Both concentrations of S-3307 reduced the length of trichomes. The two triazoles increased chloroplast size along both the long and short axes. Compared with those of controls, the stomata in the triadimefon-treated leaves were constricted and sunken, whereas in S-3307 treated leaves the subsidiary cells were wider. The effects of the triazoles observed in this study may account in part for several plant growth regulatory activities reported earlier, including growth retardation, stimulation of chlorophyll synthesis, and protection against injury from water stress.

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