scholarly journals Regulation of δ-aminolaevulinic acid synthesis and protochlorophyllide regeneration in the leaves of dark-grown barley (Hordeum vulgare) seedlings

1984 ◽  
Vol 222 (2) ◽  
pp. 419-426 ◽  
Author(s):  
A K Stobart ◽  
I Ameen-Bukhari
Keyword(s):  
Hordeum Vulgare ◽  
Acid Synthesis ◽  
Active Species ◽  
Light Treatment ◽  
High Concentration ◽  
Aminolaevulinic Acid ◽  
Low Concentrations ◽  
Sufficient Energy ◽  
Close Relationship ◽  
High Level

Laevulinic acid (Lev) was used to control the rate of protocholorophyllide (PChl) regeneration in the leaves of dark-grown seedlings of barley (Hordeum vulgare) after a brief light treatment. In the leaves given Lev, at concentrations that severely block the resynthesis of protochlorophyllide, there was a massive overproduction of delta-aminolaevulinic acid (AmLev) that was well in excess of that required for the regeneration of PChl observed in the control leaves. Lev, at low concentrations, slightly delayed regeneration and held up, rather than inhibited, the utilization of the AmLev, which accumulated in the tissues. The overproduction and uncontrolled formation of AmLev also occurred in dark-grown leaves treated with a high concentration of Lev and given a light treatment of just sufficient energy to photoreduce only small quantities of the endogenous PChl. Experiments in which a high level of free PChl was induced by incubating the leaves in AmLev indicated that the active species of PChl was that associated with, and bound to, the PChl reductase protein. The results strongly demonstrate a close relationship between the PChl-protein complex and the ability of the leaves to synthesize AmLev.

scholarly journals Photoreduction of protochlorophyllide and its relationship to δ-aminolaevulinic acid synthesis in the leaves of dark-grown barley (Hordeum vulgare) seedlings

1986 ◽  
Vol 236 (3) ◽  
pp. 741-748 ◽  
Author(s):  
A K Stobart ◽  
I Ameen-Bukhari
Keyword(s):  
Hordeum Vulgare ◽  
Ternary Complex ◽  
Red Light ◽  
Acid Synthesis ◽  
The State ◽  
Low Energy ◽  
Alternative Scheme ◽  
Aminolaevulinic Acid ◽  
Close Relationship

The photoreduction of protochlorophyllide (Pchl) in dark-grown leaves of barley (Hordeum vulgare) brings about the synthesis of delta-aminolaevulinic acid (AmLev). Manipulation of the Pchl level in the leaves by incubation in AmLev indicated that the production of AmLev was intimately related to the state of the Pchl reductase ternary complex. Free Pchl reductase that is unassociated with substrate/product appeared at first to be essential for the photoinduction of AmLev synthesis. Experiments on the photoreduction of Pchl in dark-grown leaves exposed to low-energy red-light, however, showed that photoreduction and AmLev synthesis would occur when the Pchl reductase, together with substrate, was maintained at relatively high endogenous concentration. Under such conditions the availability of free reductase protein would be negligible. An alternative scheme is presented, therefore, that can explain many, if not all, of the observations on AMLev synthesis and its close relationship to Pchl reduction, and which is based on a common supply of NADPH for the reduction of glutamate to AmLev and the synthesis of chorophyll(-ide).

Inhibition of chlorophyll synthesis in Hordeum vulgare by 3-amino 2,3-dihydrobenzoic acid (gabaculin)

1985 ◽  
Vol 5 (9) ◽  
pp. 775-781 ◽  
Author(s):  
Corinne M. Hill ◽  
Sharon A. Pearson ◽  
Arnold J. Smith ◽  
Lyndon J. Rogers
Keyword(s):  
Hordeum Vulgare ◽  
Potent Inhibitor ◽  
Acid Synthesis ◽  
Chlorophyll Synthesis ◽  
Dual Inhibitor ◽  
Aminolaevulinic Acid ◽  
Acid Dehydratase ◽  
Leaf Segments ◽  
Chlorophyll Formation ◽  
Aminolaevulinic Acid Dehydratase

Gabaculin (3-amino 2,3-dihydrobenzoic acid) is shown to be a very potent inhibitor of chlorophyll formation in Hordeum vulgate. Exposure of leaf segments to 30/μM gabaculin results in an 80% inhibition of chlorophyll synthesis, and this is paralleled by a decrease in carotenoid. Dual-inhibitor studies with dioxoheptanoic acid, which is an inhibitor of δ-aminolaevulinic acid dehydratase, show that gabaculin inhibits an earlier step than dioxoheptanoic acid and affects δ-aminolaevulinic acid synthesis rather than its subsequent metabolism.

scholarly journals Rat mammary-gland acetyl-coenzyme A carboxylase. Interaction with milk fatty acids

1970 ◽  
Vol 118 (4) ◽  
pp. 645-657 ◽  
Author(s):  
A. L. Miller ◽  
Mary E. Geroch ◽  
H. Richard Levy
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Complex Mixture ◽  
Acid Synthesis ◽  
Acetyl Coa Carboxylase ◽  
High Concentration ◽  
Acetyl Coa ◽  
Milk Fatty Acids ◽  
Low Concentrations ◽  
Rat Mammary Gland

1. Highly purified rat mammary-gland acetyl-CoA carboxylase was inhibited by milk obtained from rats 12h after their young were weaned. 2. All the inhibitory activity was found in the particulate fraction (R105) obtained on centrifuging the milk. It could be extracted from milk fraction R105 with acetone and identified as a complex mixture of non-esterified fatty acids, present in high concentration (nearly 10mm) in the milk. 3. Inhibition of acetyl-CoA carboxylase was observed at low concentrations (0.2–20μm) of several of these fatty acids when fresh fully active enzyme was used. Enzyme that had been partly inactivated by aging, or by storing in the absence of citrate, was stimulated by low concentrations but inhibited by high concentrations of fatty acids. 4. Various experiments suggested that fatty acids produce irreversible inactivation of acetyl-CoA carboxylase. 5. The effects of palmitoyl-CoA on mammary-gland acetyl-CoA carboxylase were found to resemble those of fatty acids, except that palmitoyl-CoA was effective at lower concentration. 6. The effect of milk fraction R105 was tested on six other enzymes previously shown to decline to various extents after weaning. Although several of these enzymes were affected by unfractionated milk fraction R105, none was significantly inhibited by the acetone extract or by low concentrations of lauric acid. 7. The findings are consistent, both qualitatively and quantitatively, with a regulatory mechanism whereby milk fatty acids shut off fatty acid synthesis in the mammary gland after weaning by inhibiting acetyl-CoA carboxylase.

scholarly journals Heavy metals uptake by hyperaccumulating flora in some serpentine soils of Kosovo

2016 ◽  
Vol 18 (1) ◽  
pp. 214-222 ◽  
Keyword(s):  
Heavy Metals ◽  
Ultramafic Rocks ◽  
Metamorphic Rocks ◽  
Serpentine Soils ◽  
High Concentration ◽  
Important Indicator ◽  
Low Concentrations ◽  
Close Relationship ◽  
High Concentrations ◽  
Heavy Metals Uptake

<p>Ultramafics represent magmatic or metamorphic rocks which are characterized by high concentrations of Mg, Fe, Ni, Cr and Co and low concentrations of Ca, and K. Serpentine soils are weathered products of a range of ultramafic rocks composed of ferromagnesian silicates. The aim of this study was to determine the content of heavy metals in some of serpentine soils of Kosovo and heavy metals uptake by entire associated flora. Furthermore, another objective of this study was finding out bioavailable Ca/Mg relationship, which is very important indicator for plants&rsquo; development. The sampling was conducted in June 2014. A total of three serpentine areas have been surveyed and 7 soil samples have been taken in various depths of soil profiles. Those samples were analyzed for total Ca, Cd, Co, Cr, Cu, Mn, Ni, Pb, Fe and Zn. Results showed that each site exhibited a high concentration of at least one metal. The maximum concentrations of metals in soils Dry Matter (DM) were 108.9 mg kg<sup>-1</sup> Cd, 95.8 mg kg<sup>-1</sup> Co, 1206 mg kg<sup>-1</sup> Cr, 24 mg kg<sup>-1</sup> Cu, 2570 mg kg<sup>-1</sup> Ni, 21.7 mg kg<sup>-1</sup> Pb, 39 mg kg<sup>-1</sup> Zn, and 51563 mg kg<sup>- </sup>Fe. The serpentine soils at all sites were characterized by elevated levels of heavy metals, which showed typical properties of ultramafic environments. Nickel Total at studied areas varied between 1543 and 2570 mg kg<sup>-1</sup>, while the highest Ni concentration was found in aerial part of Alyssum markgrafii (4038 mgkg<sup>-1</sup>),</p> <div> <p>Based on our findings on the field we concluded that there is a close relationship between the quantity of Ni in soil and Ni uptake in plants.</p> </div> <p>&nbsp;</p>

scholarly journals ROLE OF BIOLOGICAL PROCESSES DURING MANGANESE REMOVAL FROM UNDERGROUND WATER

2016 ◽  
Vol 1 ◽  
pp. 61-67
Author(s):  
Oleksandr Kravchenko
Keyword(s):  
Significant Role ◽  
Underground Water ◽  
Biological Processes ◽  
High Concentration ◽  
Manganese Removal ◽  
Low Concentrations ◽  
Physico Chemical ◽  
High Level ◽  
Manganese Compounds

This article briefly presents the results of the effect of oxidants during filtration of groundwater with high level of manganese compounds. Significant role of biological processes along with physico-chemical at demanganation of groundwater has been noticed. It has been studied that biological processes are dominated in low concentrations of oxidants. At high concentration of disinfectant the role of physico-chemical processes begin to dominate. Thus, there is a significant role of microorganisms in physico-chemical process of manganese removal. Obtained results showed that the oxygen is more efficient oxidizer than sodium hypochlorite for compounds of manganese presented in groundwater.

Small-volume vitrification and rapid warming yield high survivals of one-cell rat embryos in cryotubes

2021 ◽  
Author(s):  
Yasuyoshi Fukuda ◽  
Misako Higashiya ◽  
Takahiro Obata ◽  
Keita Basaki ◽  
Megumi Yano ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Small Volume ◽  
Sucrose Solution ◽  
High Concentration ◽  
Rat Embryos ◽  
Low Concentrations ◽  
Intracellular Ice Formation ◽  
Intracellular Ice ◽  
Warming Rate ◽  
Very High

Abstract To cryopreserve cells, it is essential to avoid intracellular ice formation during cooling and warming. One way to achieve this is to convert the water inside the cells into a non-crystalline glass. It is currently believed that to accomplish this vitrification, the cells must be suspended in a very high concentration (20–40%) of a glass-inducing solute, and subsequently cooled very rapidly. Herein, we report that this belief is erroneous with respect to the vitrification of one-cell rat embryos. In the present study, one-cell rat embryos were vitrified with 5 μL of EFS10 (a mixture of 10% ethylene glycol, 27% Ficoll, and 0.45 M sucrose) in cryotubes at a moderate cooling rate, and warmed at various rates. Survival was assessed according to the ability of the cells to develop into blastocysts and to develop to term. When embryos were vitrified at a 2,613 °C/min cooling rate and thawed by adding 1 mL of sucrose solution (0.3 M, 50 °C) at a warming rate of 18,467 °C/min, 58.1 ± 3.5% of the EFS10-vitrified embryos developed into blastocysts, and 50.0 ± 4.7% developed to term. These rates were similar to those of non-treated intact embryos. Using a conventional cryotube, we achieved developmental capabilities in one-cell rat embryos by rapid warming that were comparable to those of intact embryos, even using low concentrations (10%) of cell-permeating cryoprotectant and at low cooling rates.

scholarly journals LINC00842 inactivates transcription co-regulator PGC-1α to promote pancreatic cancer malignancy through metabolic remodelling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xudong Huang ◽  
Ling Pan ◽  
Zhixiang Zuo ◽  
Mei Li ◽  
Lingxing Zeng ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Acid Synthesis ◽  
Ductal Adenocarcinoma ◽  
High Concentration ◽  
Metabolic Switch ◽  
Non Coding Rna ◽  
Xenograft Models ◽  
Transcription Factor Yy1 ◽  
Catabolic Process

AbstractThe molecular mechanism underlying pancreatic ductal adenocarcinoma (PDAC) malignancy remains unclear. Here, we characterize a long intergenic non-coding RNA LINC00842 that plays a role in PDAC progression. LINC00842 expression is upregulated in PDAC and induced by high concentration of glucose via transcription factor YY1. LINC00842 binds to and prevents acetylated PGC-1α from deacetylation by deacetylase SIRT1 to form PGC-1α, an important transcription co-factor in regulating cellular metabolism. LINC00842 overexpression causes metabolic switch from mitochondrial oxidative catabolic process to fatty acid synthesis, enhancing the malignant phenotypes of PDAC cells. High LINC00842 levels are correlated with elevated acetylated- PGC-1α levels in PDAC and poor patient survival. Decreasing LINC00842 level and inhibiting fatty acid synthase activity significantly repress PDAC growth and invasiveness in mouse pancreatic xenograft or patient-derived xenograft models. These results demonstrate that LINC00842 plays a role in promoting PDAC malignancy and thus might serve as a druggable target.

scholarly journals Assessment and Imaging of Intracellular Magnesium in SaOS-2 Osteosarcoma Cells and Its Role in Proliferation

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1376
Author(s):  
Concettina Cappadone ◽  
Emil Malucelli ◽  
Maddalena Zini ◽  
Giovanna Farruggia ◽  
Giovanna Picone ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Magnesium Deficiency ◽  
Acid Synthesis ◽  
Osteosarcoma Cell ◽  
Osteosarcoma Cells ◽  
High Concentration ◽  
Proliferating Cells ◽  
Intracellular Magnesium ◽  
In Cells

Magnesium is an essential nutrient involved in many important processes in living organisms, including protein synthesis, cellular energy production and storage, cell growth and nucleic acid synthesis. In this study, we analysed the effect of magnesium deficiency on the proliferation of SaOS-2 osteosarcoma cells. When quiescent magnesium-starved cells were induced to proliferate by serum addition, the magnesium content was 2–3 times lower in cells maintained in a medium without magnesium compared with cells growing in the presence of the ion. Magnesium depletion inhibited cell cycle progression and caused the inhibition of cell proliferation, which was associated with mTOR hypophosphorylation at Serine 2448. In order to map the intracellular magnesium distribution, an analytical approach using synchrotron-based X-ray techniques was applied. When cell growth was stimulated, magnesium was mainly localized near the plasma membrane in cells maintained in a medium without magnesium. In non-proliferating cells growing in the presence of the ion, high concentration areas inside the cell were observed. These results support the role of magnesium in the control of cell proliferation, suggesting that mTOR may represent an important target for the antiproliferative effect of magnesium. Selective control of magnesium availability could be a useful strategy for inhibiting osteosarcoma cell growth.

Arsenic Contamination and its Speciation in the Water System around the Abandoned Dongil Au-Ag Mine in Korea

2005 ◽  
Vol 277-279 ◽  
pp. 503-509 ◽  
Author(s):  
Ji Min Yi ◽  
Jin Soo Lee ◽  
Hyo Taek Chon
Keyword(s):  
Stream Water ◽  
Arsenic Concentration ◽  
Water System ◽  
Arsenic Species ◽  
High Concentration ◽  
Aqua Regia ◽  
Sequential Extraction Analysis ◽  
Fe Oxyhydroxides ◽  
High Level ◽  
Stream Waters

This study was made to investigate the extent and degree of As contamination in waters and sediments influenced by previous mining activity in the abandoned Dongil Au-Ag mine. Arsenic species was also identified in surface waters and groundwater. The chemical form of As in sediments was examined using sequential extraction analysis. The major contamination source of As in the mine area is suggested to be tailings with elevated levels of 8,718 As mg/kg. This was associated with the release of high level of As into the water system in the study area. The pH values of water samples ranged from 7.7 to 10.1, which was neutral to strong alkaline due to buffering effect by high concentration of Ca and Mg dissolved from carbonate mineral and weathering of concrete. Stream waters contained high level of As within the range of 40.5 to 150.4 ㎍/L and most waters exceeded the permissible level (50 ㎍/L) of As for stream water in Korea. The concentration ratios of As(Ⅲ) to As (total), however, extended in the range of 5.8 to 75% and increased at low pH condition in stream waters. Arsenic concentration in sediments digested by aqua regia (HNO3+HCl) ranged from 162 to 2,077 mg/kg. The highest concentration of As may be due to the direct inflow of tailings. The relatively high percentage (17.1~35.3%) of As coprecipitated with amorphous Fe oxyhydroxides indicates that more severe contamination of As can occur by re-extracting due to changes of chemical environment such as reducing condition.

Drosophila cell fusion induced by wheat germ agglutinin

1975 ◽  
Vol 18 (1) ◽  
pp. 113-121
Author(s):  
R.M. Rizki ◽  
T.M. Rizki ◽  
C.A. Andrews
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Embryonic Cell ◽  
High Concentration ◽  
Drosophila Cell ◽  
Low Concentrations ◽  
Embryonic Cell Lines ◽  
Scanning Electron

The effects of wheat germ agglutinin on Drosophila embryonic cell lines growing on cover-glasses was examined by scanning electron microscopy. At low concentrations of the lectin (5-10 mug/ml), cells spread against the glass surface and fused to form syncytia. At high concentration, damage to the cell surface was evidenced as extensive membrane shrivelling and loss of surface microfilaments. Fusion also occurred under these conditions. There was some indication that the morphology of cells in division remains undisturbed by wheat germ agglutinin. The coalescence of cells and morphologic disotrtion induced by wheat germ agglutinin were not inhibited by N-acetylglucosamine, the hapten inhibitor of the lectin, under the conditions utilized in this study.

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