Water stress effects on the content of low molecular weight carbohydrates and phenolic acids in Ctenanthe setosa (Rosc.) Eichler

2000 ◽  
Vol 80 (2) ◽  
pp. 373-378 ◽  
Author(s):  
F. A. Ayaz ◽  
A. Kadioglu ◽  
R. Turgut
Keyword(s):  
Molecular Weight ◽  
Water Stress ◽  
Phenolic Acids ◽  
Phenolic Acid ◽  
Dry Weight ◽  
Low Molecular Weight ◽  
Leaf Rolling ◽  
Crystal Forms ◽  
Ctenanthe Setosa ◽  
Cis And Trans

Morphological and biochemical changes in plant cells are known as important events for adaptation to stress. In this study, changes in carbohydrate and phenolic acid concentrations during leaf rolling under water stress were investigated. Leaves of vegetatively propagated Ctenanthe setosa (Rosc.) Eichler plants started to roll after a 28-d water deficit. After approximately 33–35 d, the leaves were tightly rolled. Water stress significantly increased the dry weight of rolled leaves. Low molecular dry weight carbohydrate components identified in unrolled and rolled leaves were fructose, glucose, inositol and sucrose. Leaves of stressed plants tended to accumulate more carbohydrates of low molecular weight. The same sugars (except inositol) were also identified in liquid and crystal forms of exudates, which appeared on the abaxial surface of the leaves during leaf rolling. The phenolic acids identified in unrolled and rolled leaves were from the benzoic group (benzoic, salicylic, 4-hydroxybenzoic, vanillic, 3,4-dihydroxybenzoic, syringic acids), and the cinnamic group (ferulic and caffeic acids both in free and methyl ester form and cis- and trans-p-coumaric acids). All phenolic acid concentrations (except for salicylic acid) in the phenolic group increased in rolled leaves in comparison with unrolled leaves. In the cinnamic group, the amounts of cis- and trans-p-coumaric and caffeic acids were greater in rolled leaves than in unrolled leaves. Key words: Ctenanthe setosa, exudate, crystal, leaf rolling, sugar, phenolic acid

Characterization of Sol and Gel in Hevea Natural Rubber

1997 ◽  
Vol 70 (5) ◽  
pp. 707-713 ◽  
Author(s):  
Jitladda Tangpakdee ◽  
Yasukuki Tanaka
Keyword(s):  
Molecular Weight ◽  
Weight Fraction ◽  
Toluene Solution ◽  
Low Molecular Weight ◽  
Branch Points ◽  
Gel Content ◽  
High Ammonia ◽  
Linear Molecules ◽  
Cis And Trans

Abstract The gel content of rubber from high-ammonia latex (HA-latex) decreased significantly after deproteinization with proteolytic enzyme. The addition of 1–2% ethanol in toluene solution reduced the gel content of rubbers from HA-latex, deproteinized HA-latex (HA-DP) and pale crepe. Transesterification of the rubber in toluene solution with sodium methoxide dissolved the gel fraction. The gel fractions solubilized after transesterification showed molecular weight distribution rich in low molecular-weight fraction. The Huggins k′ constant of the fractionated rubbers from solubilized-gels was in the range of 0.42–0.45, lower than that of the fractionated HA-DP of 0.5–0.8. This indicates that all the branch-points were decomposed by transesterification to form linear molecules. The Mn values of rubber chains assembling the gel was 5.5−8.3×105 by 13C-NMR measurements of the ratio between cis- and trans-isoprene units, which were comparable to the molecular weight between crosslinks, Mc, of 7−11×105 by swelling measurements. These findings suggest that the branching and crosslinks are composed of two types of branch-points, i. e. one by association or aggregation of proteins or oligopeptides at the initiating end and the other by ester linkages including phosphoric ester at the terminal end.

Stress protein content of mature Brassica seeds and their germination performance

1998 ◽  
Vol 8 (3) ◽  
pp. 347-355 ◽  
Author(s):  
Mary Bettey ◽  
W. E. Finch-Savage
Keyword(s):  
Molecular Weight ◽  
Water Stress ◽  
Seed Development ◽  
Positive Relationship ◽  
Stress Proteins ◽  
Stress Protein ◽  
Low Molecular Weight ◽  
Optimal Conditions ◽  
Seed Vigour ◽  
The Relationship

AbstractPlants respond to sub-optimal conditions by the synthesis of specific ‘stress’ proteins, and these are thought to play a role in stress tolerance. Some of these proteins accumulate during late seed development, arguably to protect against damage during post-maturation drying and subsequent imbibition, prior to germination. Seed vigour is also determined during this late stage of seed development. High vigour seeds are those that can withstand the desiccation required for storage and successfully germinate under sub-optimal conditions to establish healthy seedlings. If stress proteins are involved in tolerating stress conditions, then they are likely to be important determinants of seed vigour. In this work the relationship between seed vigour (measured by seed germination performance following rapid aging, or under water stress) in Brassica oleracea var. capitata and the content of two classes of stress protein (dehydrins and a low molecular weight heat shock protein HSP17.6) at maturity was examined. Dehydrins did not show a positive relationship with seed performance. However, the protein HSP17.6 showed a positive correlation with seed performance, and a treatment that reduced the amount of this protein in the seed also caused a reduction in subsequent seed performance.

CO-CATALYSIS IN FRIEDEL–CRAFTS REACTIONS: VI. POLYMERIZATION OF 2-BUTENE BY BORON FLUORIDE – METHANOL

1963 ◽  
Vol 41 (4) ◽  
pp. 932-936 ◽  
Author(s):  
H. R. Allcock ◽  
A. M. Eastham
Keyword(s):  
Molecular Weight ◽  
Catalyst Concentration ◽  
Ethylene Dichloride ◽  
Low Molecular Weight ◽  
Boron Fluoride ◽  
First Order ◽  
Order Dependence ◽  
Rate Of Polymerization ◽  
Cis And Trans

2-Butene is polymerized by boron fluoride and methanol in ethylene dichloride solution at ordinary temperatures to give very low molecular weight polymers. The rate of polymerization shows exactly the same dependence on catalyst concentration as did the rate of isomerization of the cis- and trans-2-butenes, i.e. first order both in free boron fluoride and in the boron fluoride – methanol complex. The polymerization, however, shows a first-order dependence in olefin over a concentration range where the isomerization is, experimentally, virtually independent of the olefin concentration.

Radioisomerization and Photoisomerization of Liquid 2 -Butenes in the Presence of Sulfur Compounds

1974 ◽  
Vol 52 (12) ◽  
pp. 2337-2340 ◽  
Author(s):  
Guy J. Collin ◽  
Patrick M. Perrin ◽  
François X. Garneau
Keyword(s):  
Molecular Weight ◽  
Hydrogen Sulfide ◽  
Liquid Phase ◽  
Molecular Oxygen ◽  
Carbon Disulfide ◽  
Sulfur Hexafluoride ◽  
The Other ◽  
Isomerization Reaction ◽  
Low Molecular Weight ◽  
Cis And Trans

The liquid phase radiolysis and photolysis of cis- and trans-2-butenes were studied in the presence of various additives. A very efficient isomerization of 2-butenes was achieved by the addition of thiols of low molecular weight (hydrogen sulfide, methyl and isopropyl mercaptans). In the absence of molecular oxygen, we have observed G values (trans-2-butene) of the order of 90 000. On the other hand, little or no isomerization occurred in the presence of carbon disulfide, sulfur hexafluoride, and tert-dodecylmercaptan. Although the majority of the additives have no effect on the 2-butene:hydrogen sulfide system, conjugated diolefins block the isomerization reaction. These diolefins disappear from the reaction mixture.

The allelopathic potential of phenolic acids associated with the rhizosphere of Pteridium aquilinum

1976 ◽  
Vol 54 (21) ◽  
pp. 2440-2444 ◽  
Author(s):  
Anthony D. M. Glass
Keyword(s):  
Root Growth ◽  
Phenolic Acids ◽  
Phenolic Acid ◽  
Dry Weight ◽  
Pteridium Aquilinum ◽  
Fresh Weight ◽  
Root Volume ◽  
Allelopathic Potential ◽  
Lateral Root Development ◽  
Seminal Roots

Barley plants were grown hydroponically in solutions which exactly reproduced the major phenolic acid composition of the soil associated with Pteridium aquilinum (L.) Kuhn. In CaSO4 solution these compounds severely inhibited root growth as measured by fresh weight, dry weight, and root volume analyses. The form of root growth was also modified by the presence of the phenolic acids in that by 3 weeks extensive lateral root development had occurred, whereas only limited elongation of seminal roots occurred. Inhibition, as measured by fresh weight determinations, was most pronounced when roots were grown at 5 and 30 °C and least pronounced between 15 and 20 °C. Other species examined, with the sole exception of Agropyron repens (L.)Beauv., showed similar responses to the presence of the phenolic acids. Microscopic examination of the tips of barley roots treated with phenolic acid revealed that meristematic cells were prematurely vacuolated.In constrast with the striking effects of these phenolics on root growth in CaSO4 solution, there were no obvious effects on barley root growth when the phenolic acids were dissolved in a complete inorganic nutrient medium.

Polyethersulfone polymers and oligomers — Morphology and crystallization

2012 ◽  
Vol 90 (10) ◽  
pp. 880-890 ◽  
Author(s):  
Abdelkader Benhalima ◽  
François Hudon ◽  
Finda Koulibaly ◽  
Christian Tessier ◽  
Josée Brisson
Keyword(s):  
Molecular Weight ◽  
Model Compound ◽  
Crystal Form ◽  
Low Molecular Weight ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Crystal Forms ◽  
X Ray ◽  
Diphenyl Sulfone ◽  
Induced Crystallization

Crystal forms of polyethersulfones (PES) were investigated by using a model compound and a low molecular weight oligomer. These are amorphous as-synthesized, and can undergo solvent-induced crystallization under the appropriate conditions. The model compound, 4,4′-bis(p-methoxyphenoxy)diphenyl sulfone, yielded monocrystals, and its structure was solved using X-ray diffraction. Conformational disorder is present, two conformers cohabiting in 55:45 proportions. This model compound, combined to previous structural studies published in the literature, served as a basis for conformational studies of polyethersulfone. Low molecular weight polymers submitted to solvent-induced crystallization resulted in a PES crystal form different from that previously published in the literature, as shown by powder X-ray diffraction.

Mechanisms of Sb(III) oxidation mediated by low molecular weight phenolic acids

2019 ◽  
Vol 356 ◽  
pp. 190-198 ◽  
Author(s):  
Tong-liang Wu ◽  
Wen-xiu Qin ◽  
Marcelo Eduardo Alves ◽  
Guo-dong Fang ◽  
Qian Sun ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Phenolic Acids ◽  
Low Molecular Weight

scholarly journals Polycyclic Aromatic Hydrocarbons (PAHs) in water of Al-Kahlaa River in Missan Province, Iraq

2016 ◽  
Vol 21 (1) ◽  
pp. 1
Author(s):  
Salih Hassan Jazza ◽  
Abdul Hussain Y. Al-Adhub ◽  
Hamid T. Al-Saad
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Dry Weight ◽  
Reference Station ◽  
Low Molecular Weight ◽  
Treatment Unit ◽  
Tigris River ◽  
Polycyclic Aromatic ◽  
Total Concentrations

The present study was performed to have knowledge of Polycyclic Aromatic  Hydrocarbonspollution status in water. The samples were collected during two seasons (winter and summer 2012 ,2013) from four different stations) Al-Magideh, Treatment unit, Al-Husaichi and Al-Zubair) distributed along Al-KahlaaRiver in Missan province, in addition to reference station lies on the Tigris river before  25 Km  from entering to Amara city. The concentrations of PAHs were determined in by using capillary Gas Chromatography. Results of the present  study revealed that the total concentrations of PAHs  in dissolved fraction  ranged from 0.739 ng.l-1 in Reference station to 1.974 ng.l-1 in Treatment unit during winter, and from 0.300 ng.l-1 in Reference station to 1.125 ng.l-1 in Treatment unit during summer, while in the particulate fraction they varied from 0.79 ng.g-1 dry weight in Reference station to 24.42  ng.g-1 dry weight in Treatment unit during winter, and from 4.369 ng.g-1 dry weight in Reference station to 10.545 ng.g-1 dry weight in Al-Husaich during summer. It had been noticed that there were a predominance of high molecular weight PAHs on low molecular weight, while  BaA/(BaA+Chr) ratio in water ranged from 0.218 to 0.804. InP/(InP+BghiP) ratio ranged between 0 and 0.578,whereas Fl/Pyratio ranged between 0.150 and 2 ,this give an indication of  the origin  of PAHs compounds in water which were mainly pyrogenic and few from them  petrogenic. Keywords: polycyclic aromatic hydrocarbons, PAHs, water, pollution

scholarly journals Accumulation of Phenolic Acids during Storage over Differently Handled Fresh Carrots

Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1515
Author(s):  
Jarkko Hellström ◽  
Daniel Granato ◽  
Pirjo H. Mattila
Keyword(s):  
Phenolic Acids ◽  
Phenolic Acid ◽  
High Resolution Mass Spectrometry ◽  
Storage Period ◽  
Dry Weight ◽  
Total Phenolic ◽  
Case Processing ◽  
Minimal Processing ◽  
Technological Processing ◽  
Selection Of

Carrots contain a significant content of phenolic compounds, mainly phenolic acids. Technological processing of carrots inflicts wounding stress and induces accumulation of these compounds, especially caffeic acid derivatives, in the periderm tissue. In this study, the effect of minimal processing (polishing, washing, peeling, and grating) on the retention of soluble phenolic acids in carrots was monitored during cold storage. Storage for up to 4 weeks and 24 h was used for whole and grated carrot samples, respectively. Total phenolic acid levels found in differently processed carrots varied greatly at the beginning of the storage period and on dry weight basis they ranged from 228 ± 67.9 mg/kg (grated carrot) to 996 ± 177 mg/kg (machine washed). In each case, processing followed by storage induced phenolic acid accumulation in the carrots. At the end of the experiment (4 weeks at +8 °C), untreated and machine-washed carrots contained ca. 4-fold more phenolic acids than at day 0. Similarly, polished carrots contained 9-fold and peeled carrots 31-fold more phenolic acids than at day 0. The phenolic acid content in grated carrot doubled after 24 h storage at +4 °C. Individual phenolic acids were characterized by high resolution mass spectrometry. MS data strongly suggest the presence of daucic acid conjugates of phenolic acids in carrot. Storage time did not have statistically similar effect on all compounds and generally in a way that dicaffeoyldaucic acid had the highest increase. This research provides important information for primary production, packaging, catering, the fresh-cut industry and consumers regarding the selection of healthier minimally processed carrots.

scholarly journals On the venom of the lesser weeverfish, Trachinus vipera

1962 ◽  
Vol 42 (2) ◽  
pp. 155-162 ◽  
Author(s):  
D. B. Carlisle
Keyword(s):  
Molecular Weight ◽  
Toxic Effect ◽  
Dry Weight ◽  
Weight Basis ◽  
Low Molecular Weight ◽  
Neurotoxic Effect ◽  
Local Pain ◽  
Dorsal Fin ◽  
Single Complex

SUMMARYA method is described for obtaining the venom from the dorsal fin of the lesser weever without harming the fish. It is suggested that the amount of venom normally injected into the wound by the weever when it stings is O-5-O-2 mg dry weight of venom. Some 60% of the dry weight of the venom appears to consist of toxic muco-substances, which have a neurotoxic effect, but are without toxic effect on the blood. In extracts this fraction may be separated into two albumins and an amino polysaccharide, though in the native venom these are probably associated into a single complex mucosubstance. When injected subcutaneously this fraction of the venom produces no local pain. The venom also contains about 1-20 jug/mg (dry-weight basis) of 5-hydroxytryptamine which appears to be the origin of the pain of the sting, together with some undetermined histamine releaser (not an indole) of low molecular weight. It is suggested that the chief role of the 5-hydroxytryptamine in the venom is to produce pain around the area of the inflicted wound.

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