scholarly journals Studies on the polyphenol metabolism of tissue cultures derived from the tea plant (Camellia sinensis L.)

1969 ◽  
Vol 113 (5) ◽  
pp. 765-772 ◽  
Author(s):  
G. I. Forrest
Keyword(s):  
Growth Rate ◽  
Callus Tissue ◽  
High Light Intensity ◽  
Tea Plant ◽  
Anthocyanin Synthesis ◽  
Polyphenol Oxidase Activity ◽  
Intact Plants ◽  
Liquid Suspension ◽  
High Concentrations ◽  
Root Apices

1. The growth characteristics on various media of solid and liquid suspension cultures derived from the stem of the tea plant are described; chlorophyll and anthocyanin synthesis occurred in the light. 2. Only the simplest catechins and leucoanthocyanins were present in callus tissue, although oligomeric and polymeric leucoanthocyanin fractions were also represented. Light caused an increase in all monomeric components analysed, but inhibited polymerization of the leucoanthocyanins. 3. The polyphenol oxidase activity of cultures was comparable with that of the apical regions of the intact plant, and was inversely correlated with growth rate. 4. Growth was stimulated by hormonal variation, and inhibited by high concentrations of sucrose and by high light-intensity; polyphenol concentrations were generally inversely correlated with growth rate. 5. From the inability of callus tissue and of cultured root apices to synthesize complex catechins, it is inferred that complex catechin formation in intact plants is associated with the process of cell vacuolation.

scholarly journals The distribution of polyphenols in the tea plant (Camellia sinensis L.)

1969 ◽  
Vol 113 (5) ◽  
pp. 741-755 ◽  
Author(s):  
G. I. Forrest ◽  
D S Bendall
Keyword(s):  
Tea Plant ◽  
Steady Increase ◽  
Protective Layers ◽  
Mature Leaves ◽  
High Concentrations ◽  
Root Apices ◽  
Layer Chromatography ◽  
Derivatives Of ◽  
Ring Hydroxylation

1. Methods for the separation and determination of the polyphenolic components of the tea plant by thin-layer chromatography and colorimetric reactions have been devised. 2. High concentrations of catechins, flavonols and depsides were found to be restricted to the young vegetative and floral shoots, whereas leucoanthocyanins or flavylogens were characteristic of the more bulky axial tissues of the plant. 3. In the young shoots cell growth was correlated with an increasing degree of flavonoid B-ring hydroxylation. 4. Maximal flavylogen concentrations occurred in the outer protective layers of stem and of seed coat. 5. Mature leaves were shown to contain derivatives of the flavones apigenin and luteolin. 6. Developing seedlings showed a steady increase in polyphenol complexity; flavylogens were concentrated at shoot and root apices and accumulated at the stem base. 7. It is postulated that the flavanols (leucoanthocyanins and catechins), because they can co-polymerize, are of use to the plant for protection of wood and bark against infection and decay.

Effect of caffeine on the growth and photosynthetic efficiency of marine macroalgae

2021 ◽  
Vol 64 (1) ◽  
pp. 13-18
Author(s):  
Ira Gray ◽  
Lindsay A. Green-Gavrielidis ◽  
Carol Thornber
Keyword(s):  
Growth Rate ◽  
Photosynthetic Efficiency ◽  
Sublethal Effects ◽  
Marine Species ◽  
Marine Organisms ◽  
Marine Macroalgae ◽  
Chondrus Crispus ◽  
Coastal Environments ◽  
Codium Fragile ◽  
High Concentrations

Abstract Caffeine is present in coastal environments worldwide and there is a need to assess its impact on marine organisms. Here, we exposed two species of ecologically important marine macroalgae (Chondrus crispus and Codium fragile subsp. fragile) to a suite of caffeine concentrations and measured their response. Caffeine concentrations of 10–100 ng L−1 had no significant effect on the growth rate or photosynthetic efficiency of either algae. Extremely high concentrations (100–200 mg L−1), which may occur acutely, produced sublethal effects for both species and mortality in C. fragile subsp. fragile. Our results highlight the need to understand how caffeine impacts marine species.

Vitrification Solutions for the Cryopreservation of Tissue-Engineered Bone

2002 ◽  
Author(s):  
B. L. Liu ◽  
J. J. McGrath
Keyword(s):  
Bending Strength ◽  
Cell Damage ◽  
Mechanical Damage ◽  
Bone Substitutes ◽  
State University ◽  
Scanning Calorimetry ◽  
Destructive Effect ◽  
Cryoprotective Agents ◽  
Liquid Suspension ◽  
High Concentrations

Osteoblast (OB)-seeded hydroxyapatite (HA) scaffold cortical bone substitutes are being developed at Michigan State University. Preservation methods need to be developed to preserve such living products to ensure a steady supply for transplantation. Theoretically vitrification is an attractive method for the cryopreservation of tissue-engineered bone because it can eliminate the destructive effect of ice formation [1]. However, relatively fast cooling and warming rates are required to avoid damage associated with ice crystallization and relatively high concentrations of cryoprotective agents (CPAs) are required to achieve a glassy (vitrified) state. These rapid rates of temperature change may not be possible as tissue-engineered structures become larger. In addition to cell damage, rapid rates may also cause destructive thermo mechanical damage to the scaffold itself. Slower rates can be used to achieve the vitrified state but this requires higher CPA concentrations, which are more toxic. As a means of studying the interactive determinants of an optimal vitrification process for osteoblasts, we have undertaken thermal analysis of a variety of vitrification solutions of interest using differential scanning calorimetry (DSC) to determine the critical cooling and warming rates. The toxicity dynamics and tendency for the scaffolds to be damaged mechanically by the vitrification process are also examined. Glycerol and dimethyl sulfoxide at a concentration of 40% were studied with and without an ice blocker. Two vitrification “cocktails” (VS55 and VEG) over a concentration range of 80% to 100% were studied with and without an ice blocker. On the basis of these studies 95% VEG with ice blocker was least toxic and yielded the highest recovery (∼90%) for OBs vitrified in liquid suspension. Vitrification does not seem to be detrimental to the bending strength of high density (low porosity) HA scaffolds, but lower density HA scaffolds break more easily after vitrification in some instances.

Growth and Doping Kinetics of GexSil-x Structures by Limited Reaction Processing

1989 ◽  
Vol 146 ◽  
Author(s):  
P.M. Garone ◽  
J.C. Sturm ◽  
P.V. Schwartz ◽  
S.A. Schwarz ◽  
B. Wilkens
Keyword(s):  
Growth Rate ◽  
Boron Doping ◽  
Epitaxial Films ◽  
Growth Regime ◽  
Simple Kinetic Model ◽  
Silicon Growth ◽  
High Concentrations ◽  
Reaction Processing ◽  
Kinetics Of ◽  
Growth Experiments

ABSTRACTWe have investigated the growth rate and boron doping of Sil-xGex epitaxial films grown by Limited Reaction Processing The growth experiments were carried out at a pressure of 6.0 torr with growth temperatures ranging from 625°C to 1000°C. The growth rate increases rapidly upon the additon of a small germane flow to the dichlorosilane in the reaction-rate-limited growth regime, and can not be explained simply by germanium incorporation. The presence of germane can increase the silicon growth rate by up to a factor of one hundred. Boron doping was also studied at high concentrations of boron in Si and Sil-xGex epitaxial films as a function of diborane flow and growth rate supports a simple kinetic model rather than an equilibrium model.

scholarly journals Effects of 5-azacytidine on the progressive nature of cell transformation.

1985 ◽  
Vol 5 (7) ◽  
pp. 1800-1803 ◽  
Author(s):  
W L Hsiao ◽  
S Gattoni-Celli ◽  
I B Weinstein
Keyword(s):  
Dna Methylation ◽  
Growth Rate ◽  
Tumor Cells ◽  
Mouse Embryo ◽  
Cell Transformation ◽  
Multistage Carcinogenesis ◽  
Mouse Embryo Fibroblasts ◽  
Liquid Suspension ◽  
Density Growth ◽  
Growth Properties

C3H 10T1/2 mouse embryo fibroblasts were exposed to 3 microM 5-azacytidine for 24 h and then serially passaged in the absence of 5-azacytidine and examined for subsequent changes in growth properties. The treated cells showed changes in morphology, saturation density, growth rate, and serum dependence. By the 5th passage they acquired the ability to grow in 0.3% agarose, and by the 30th passage they gave rise to fully transformed foci that grew in agarose, in agar, and in liquid suspension. This progression was rapidly accelerated if the cultures derived from 5-azacytidine-treated cells were exposed for 48 h to the carcinogen benzo[a]pyrene. Results of these studies provide evidence that aberrations in DNA methylation may be one of a series of critical events during the course of multistage carcinogenesis and thus enhance the evolution of tumor cells.

scholarly journals Ascorbate biosynthesis and function in photoprotection

2000 ◽  
Vol 355 (1402) ◽  
pp. 1455-1464 ◽  
Author(s):  
Nicholas Smirnoff
Keyword(s):  
Active Oxygen Species ◽  
Electron Flow ◽  
High Light Intensity ◽  
High Light ◽  
Pool Size ◽  
Ultraviolet B ◽  
Photochemical Quenching ◽  
Inner Mitochondrial Membrane ◽  
Oxidative Stresses ◽  
High Concentrations

Ascorbate (vitamin C) can reach very high concentrations in chloroplasts (20–300 mM).The pool size in leaves and chloroplasts increases during acclimation to high light intensity and the highest concentrations recorded are in high alpine plants. Multiple functions for ascorbate in photosynthesis have been proposed, including scavenging of active oxygen species generated by oxygen photoreduction and photorespiration, regeneration of α–tocopherol from α–tocopheryl radicals, cofactor for violaxanthin de–epoxidase and donation of electrons to photosystem II. Hydrogen peroxide scavenging is catalysed by ascorbate peroxidase (Mehler peroxidase reaction) and the subsequent regeneration of ascorbate by reductant derived from photosystem I allows electron flow in addition to that used for CO 2 assimilation. Ascorbate is synthesized from guanosine diphosphate–mannose via L–galactose and L–galactono–1,4–lactone. The last step, catalysed by L–galactono–1,4–lactone dehydrogenase, is located on the inner mitochondrial membrane and uses cytochrome c as electron acceptor. L–galactono–1,4–lactone oxidation to ascorbate by intact leaves is faster in high–light acclimated leaves and is also enhanced by high light, suggesting that this step contributes to the control of pool size by light. Ascorbate–deficient Arabidopsis thaliana vtc mutants are hypersensitive to a number of oxidative stresses including ozone and ultraviolet B radiation. Further investigation of these mutants shows that they have reduced zeaxanthin–dependent non–photochemical quenching, confirming that ascorbate is the cofactor for violaxanthin de–epoxidase and that availability of thylakoid lumen ascorbate could limit this reaction. The vtc mutants are also more sensitive to photooxidation imposed by combined high light and salt treatments.

Ochrobactrum tritici strain 5bvl1 — characterization of a Cr(VI)-resistant and Cr(VI)-reducing strain

2004 ◽  
Vol 50 (9) ◽  
pp. 697-703 ◽  
Author(s):  
Rita Branco ◽  
M Carmen Alpoim ◽  
Paula V Morais
Keyword(s):  
Heavy Metal ◽  
Growth Rate ◽  
Type Strain ◽  
Treatment Plant ◽  
The Other ◽  
Reducing Ability ◽  
High Concentrations ◽  
Ph Range ◽  
Ochrobactrum Tritici

Bacterial strain 5bvl1, isolated from a chromium-contaminated wastewater treatment plant and identified as Ochrobactrum tritici, was resistant to a broad range of antibiotics, to Cr(VI), Ni(II), Co(II), Cd(II), and Zn(II), and was able to grow in the presence of 5% NaCl and within the pH range 4–10. Characterization showed that strain 5bvl1 could be considered a halotolerant and alkalitolerant microorganism resistant to high concentrations of Cr(VI). This strain was able to grow aerobically in up to 10 mmol·L–1 Cr(VI). Cr(VI) resistance was independent of sulphate concentration. Under aerobic conditions strain 5bvl1 was also able to reduce high Cr(VI) concentrations (up to 1.7 mmol·L–1). Increasing concentrations of Cr(VI) in the medium lowered the growth rate of strain 5bv11 but the reduction in growth rate could not be directly correlated with the amount of Cr(VI) reduced. Unlike the type strain, which was only able to reduce Cr(VI), strain 5bvl1 was resistant to Cr(VI) and able to reduce it. Moreover, in strain 5bvl1, the rate and extent of Cr(VI)-reduction were higher than in the other strains of the genus Ochrobactrum. Ochrobactrum strain 5bvl1 resists high Cr(VI) concentrations and has a high Cr(VI)-reducing ability, making it a valuable tool in bioremediation.Key words: Ochrobactrum, Cr(VI) resistance, Cr(VI)-reduction, heavy metal, bioremediation.

Calcium-accumulating cells in the meristematic region of grapevine root apices

2003 ◽  
Vol 30 (6) ◽  
pp. 719 ◽  
Author(s):  
Richard Storey ◽  
R. Gareth Wyn Jones ◽  
Daniel P. Schachtman ◽  
Michael T. Treeby
Keyword(s):  
Primary Root ◽  
Outer Region ◽  
Root Apex ◽  
Root Tip ◽  
Cortical Cells ◽  
Major Cations ◽  
High Calcium ◽  
High Concentrations ◽  
Root Apices ◽  
Crystal Idioblast

Apical roots of grapevines were examined by cryo-SEM (scanning electron microscopy) and the intracellular distribution of Ca was demonstrated by X-ray microanalysis in different regions of the primary root. We show that large amounts of Ca are accumulated as raphide crystals in the vacuoles of specialised cortical cells (idioblast cells) of the root apex. These crystal idioblast cells appeared to form a discontinuous cone of cells in the outer region of the root meristem. The raphide crystals within these cells were less apparent in older regions of the root, 10–12 mm basipetal to the root tip. We suggest that the raphide crystals could initially act as another Ca sink involved in the regulation of Ca levels in root apices. In older regions of the root these cells are spaced at intervals around the periphery of the cortex and the subsequent disappearance of the raphides may be indicative of remobilisation, perhaps in the zone of elongation where cell wall synthesis occurs and Ca demand is high. Calcium-accumulating cells were also observed in the older regions of the root, forming endodermal protrusions extending into the cortex. These cells may play a part in regulating Ca delivery to the xylem stream by sequestration of Ca from the radial flow of water at the endodermis. The observed distribution of Ca in root apices was different from the other major cations (e.g. K) and anions (e.g. Cl) because high concentrations were localised to specific cells. We interpret the results in the context of a model of the dynamics of grapevine root growth and cell differentiation, and the temporal balance of solute supply from the protophloem and the external medium.

scholarly journals Experimental researches on vegetable assimilation and respiration. XVIII.—The relation between stomatal opening and assimilation.—A critical study of assimilation rates and porometer rates in leaves of Cherry Laurel

1928 ◽  
Vol 102 (720) ◽  
pp. 488-533 ◽  
Keyword(s):  
Light Intensity ◽  
Diurnal Rhythm ◽  
High Light Intensity ◽  
High Light ◽  
Stomatal Opening ◽  
Critical Study ◽  
Assimilation Rate ◽  
High Concentrations ◽  
Experimental Researches ◽  
Cherry Laurel

In a previous communication it was shown that there is, in Cherry Laurel leaves, at “limiting” concentrations of CO 2 , a marked diurnal rhythm of apparent assimilation. In spite of the maintenance of a constant high light intensity, the assimilation rate falls to very low values during the night but rises again in the morning. At high concentrations of CO 2 , such that light, instead of CO 2 , is limiting the rate, there is no diurnal rhythm, the light limited value of assimilation being steadily maintained for more than 24 hours. There is, in addition to the diurnal rhythm, a seasonal rhythm of assimilation—the pitch or level of the diurnal assimilation curves being higher in November than in July, August and September. Also the level of assimilation, for a given “limiting” concentration of CO 2 , is higher at high light intensity than at low. It was suggested that these variations in assimilation were largely due to variations in stomatal opening. The work on porometer rates and assimilation rates described in the present paper was undertaken in order to test this hypothesis and to explore, as far as was possible by such means, the relation between stomatal opening and assimilation rate.

Behavior of BAS-9052 OH in Soybean (Glycine max) and Johnsongrass (Sorghum halepense) Plant and Cell Cultures

Weed Science ◽  
1982 ◽  
Vol 30 (6) ◽  
pp. 640-650 ◽  
Author(s):  
Beth A. Swisher ◽  
Frederick T. Corbin
Keyword(s):  
Glycine Max ◽  
Cell Cultures ◽  
Microscopic Examination ◽  
Leaf Primordia ◽  
Sorghum Halepense ◽  
Leaf Stage ◽  
Intact Plants ◽  
Treated Leaf ◽  
Soybean Plants ◽  
Root Apices

Research involved the behavior of BAS-9052 OH {2[1-(ethoxyimino)butyl]-5-[2(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} in soybean [Glycine max(L.) Merr.] and johnsongrass [Sorghum halepense(L.) Pers.] plants, and the fate of14C-BAS-9052 OH in intact plants and cell cultures of both species. Microscopic examination of seedling johnsongrass plants (two- to three-leaf stage) treated with foliar applications of 0.48 μg/plant revealed disorganized apical regions and necrotic cells within the apex and leaf primordia of the shoot. Necrotic zones were also evident at the base of expanding leaves and in root apices 1 day after treatment. Following application of14C-BAS-9052 OH, the same radioactive products were isolated from cell cultures and intact plants. Products included BAS-9052 OH and three unidentified metabolites. Greater proportions of unchanged BAS-9052 OH were extracted from the apical leaves, roots, and cell cultures of johnsongrass than of soybean. BAS-9052 OH was thermal and photo-labile, and a large portion of14C may not have entered the plant as BAS-9052 OH. However, tolerant soybean plants and cell cultures appeared to have metabolized the herbicide more rapidly than susceptible johnsongrass plants and cell cultures. An average of 64% of the14C remained in the treated leaf of johnsongrass compared with 48% in soybean. About one-half as much14C was translocated to the apical leaves of susceptible johnsongrass than tolerant soybean. Therefore, differential uptake and translocation cannot account for the selectivity of BAS-9052 OH.

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