BIOSYNTHESIS OF MUSTARD OIL GLUCOSIDES: I. ADMINISTRATION OF C14-LABELLED COMPOUNDS TO HORSERADISH, NASTURTIUM, AND WATERCRESS

1962 ◽  
Vol 40 (1) ◽  
pp. 1505-1514 ◽  
Author(s):  
E. W. Underhill ◽  
M. D. Chisholm ◽  
L. R. Wetter
Keyword(s):  
Allyl Isothiocyanate ◽  
The Other ◽  
Mustard Oil ◽  
Methyl Carbon ◽  
Nasturtium Officinale ◽  
Other Hand ◽  
Tropaeolum Majus ◽  
Armoracia Lapathifolia ◽  
Carboxyl Carbon

Biosynthetic investigations with C14-labelled compounds indicate that the aromatic isothiocyanate moieties of mustard oil glucosides obtained from garden nasturtium (Tropaeolum majus L.) and watercress (Nasturtium officinale R.Br.) are derived from phenylalanine. Similar investigations on sinigrin, the mustard oil glucoside isolated from horseradish (Armoracia lapathifolia Gilib.) demonstrate that glycine is incorporated into allyl isothiocyanate. The methyl carbon of acetate was readily incorporated into sinigrin and gluconasturtium and was found almost exclusively in the 'isothiocyanate carbon'; on the other hand the carboxyl carbon is a poor precursor of sinigrin.

BIOSYNTHESIS OF MUSTARD OIL GLUCOSIDES: I. ADMINISTRATION OF C14-LABELLED COMPOUNDS TO HORSERADISH, NASTURTIUM, AND WATERCRESS

1962 ◽  
Vol 40 (11) ◽  
pp. 1505-1514 ◽  
Author(s):  
E. W. Underhill ◽  
M. D. Chisholm ◽  
L. R. Wetter
Keyword(s):  
Allyl Isothiocyanate ◽  
The Other ◽  
Mustard Oil ◽  
Methyl Carbon ◽  
Nasturtium Officinale ◽  
Other Hand ◽  
Tropaeolum Majus ◽  
Armoracia Lapathifolia ◽  
Carboxyl Carbon

Biosynthetic investigations with C14-labelled compounds indicate that the aromatic isothiocyanate moieties of mustard oil glucosides obtained from garden nasturtium (Tropaeolum majus L.) and watercress (Nasturtium officinale R.Br.) are derived from phenylalanine. Similar investigations on sinigrin, the mustard oil glucoside isolated from horseradish (Armoracia lapathifolia Gilib.) demonstrate that glycine is incorporated into allyl isothiocyanate. The methyl carbon of acetate was readily incorporated into sinigrin and gluconasturtium and was found almost exclusively in the 'isothiocyanate carbon'; on the other hand the carboxyl carbon is a poor precursor of sinigrin.

BIOSYNTHESIS OF MUSTARD OIL GLUCOSIDES: VII. FORMATION OF SINIGRIN IN HORSERADISH FROM HOMOMETHIONINE-2-14C AND HOMOSERINE-2-14C

1966 ◽  
Vol 44 (12) ◽  
pp. 1625-1632 ◽  
Author(s):  
M. D. Chisholm ◽  
L. R. Wetter
Keyword(s):  
Amino Acids ◽  
Allyl Isothiocyanate ◽  
Valeric Acid ◽  
The Other ◽  
Mustard Oil ◽  
Armoracia Lapathifolia ◽  
Hydroxyvaleric Acid

Five 14C-labeled amino acids were administered to horseradish (Armoracia lapathifolia Gilib.) leaves. Three of the amino acids, DL-homoserine-2-14C, DL-methionine-2-14C, and DL-homomethionine-2-14C (2-amino-5-(methylthio)-valeric acid), were precursors of the aglycone (allyl isothiocyanate) of sinigrin. The other two, DL-allylglycine-2-14C (2-amino-4-pentenoic acid) and DL-2-amino-5-hydroxyvaleric acid-2-14C, were incorporated in insignificant amounts. The relationships of the three efficient precursors are discussed. The syntheses of four 14C-labeled amino acids used in this investigation are described.

Sources of sulfur in the thioglucosides of various higher plants

1968 ◽  
Vol 46 (8) ◽  
pp. 931-935 ◽  
Author(s):  
L. R. Wetter ◽  
M. D. Chisholm
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Higher Plants ◽  
Carbon Skeleton ◽  
The Other ◽  
Nasturtium Officinale ◽  
Tropaeolum Majus ◽  
Armoracia Lapathifolia

L-Methionine-35S and DL-cysteine-35S were good sources of sulfur for the biosynthesis of sinigrin in Armoracia lapathifolia Gilib. and were incorporated with approximately the same efficiency. Homomethionine-35S was a slightly poorer source of sulfur than methionine, while taurine-35S was a very poor source. When homomethionine, methionine, and cysteine were employed as sources of sulfur, the distribution of radioactivity between the two sulfur atoms in sinigrin was approximately 80% in the isothiocyanate moiety and 10–15% in the sulfate moiety. When taurine was employed, the distribution was reversed. 1-Thio-β-D-glucose (1-thioglucose) also was a poor source of sulfur for sinigrin. The carbon skeleton of 1-thioglucose was only slightly incorporated into this thioglucoside. The experiments indicated that 1-thioglucose was not a direct precursor of the 1-thioglucosyl residue of sinigrin.The administration of doubly labeled methionine-2-14C-35S clearly demonstrated that this amino acid was not incorporated intact into sinigrin. The carbon-2 and sulfur atoms were metabolized by two different routes.Preliminary studies related to sulfur incorporation into the thioglucosides of Nasturtium officinale R.Br., Tropaeolum majus L., and Reseda luteola L. indicated that there were some differences depending on the source of sulfur; DL-cysteine was a better source of sulfur than either methionine or 1-thioglucose. Tropaeolum majus L. appeared to utilize the sulfur of cysteine for the production of thioglucoside as efficiently as Armoracia lapathifolia Gilib.; however, the other two species utilized the sulfur from the amino acids very poorly.

scholarly journals II. Compounds isomeric with the sulphocyanic ethers.—I. On the mustard oil of the ethyl series

1868 ◽  
Vol 16 ◽  
pp. 254-258
Keyword(s):  
Royal Society ◽  
The Other ◽  
Mustard Oil ◽  
Other Hand ◽  
Derivatives Of

The results of my researches on the chloroform-derivatives of the primary monamines, which, as I have shown, are isomeric with the nitriles, could not fail to direct my attention to allied groups of bodies, with the view of discovering similar isomerisms. In a note communicated to the Royal Society some months ago, I expressed the expectations which even then appeared to be justified in the following manner:—“In conclusion, I may be permitted to announce as everv probable the existence of a series of bodies isomeric with the sulphocyanides. Already M. Cloëz has shown that the action of chloride of cyanogen on ethylate of potassium gives rise to the formation of an ethylic cyanate possessing properties absolutely different from those belonging to the cyanate discovered by M. Wurtz. On comparing, on the other hand the properties of the methylic and ethylic sulphocyamdes with those of the sulphocyanides of allyl and phenyl, it can scarcely be doubted that we have here the representatives of two groups entirely different, and that the terms of the methyl- and ethyl-series which correspond to oil of mustard, and to the sulphocyanide of phenyl, still remain to be discovered. Experiments with which I am now engaged will show whether these bodies cannot be obtained by the action of the iodides of methyl and ethyl on sulphocyanide of silver."

BIOSYNTHESIS OF MUSTARD OIL GLUCOSIDES: IV. THE ADMINISTRATION OF METHIONINE-C14 AND RELATED COMPOUNDS TO HORSERADISH

1964 ◽  
Vol 42 (7) ◽  
pp. 1033-1040 ◽  
Author(s):  
M. D. Chisholm ◽  
L. R. Wetter
Keyword(s):  
Degradation Products ◽  
Allyl Isothiocyanate ◽  
Chemical Degradation ◽  
Mustard Oil ◽  
Methyl Group ◽  
Armoracia Lapathifolia ◽  
Related Compounds

The administration of C14-labelled compounds to horseradish (Armoracia lapathifolia Gilib.) demonstrated that both methionine and acetate were efficiently incorporated into the aglycone (allyl isothiocyanate) of sinigrin. Chemical degradation of the aglycone showed that the methyl group of acetate appeared in the "isothiocyanate carbon" and that carbons 2, 3, and 4 of methionine were incorporated into carbons 2, 3, and 4 respectively of the aglycone with very little randomization. Homocysteine was the only other compound that was incorporated into the aglycone. Other degradation products of methionine did not appear to be incorporated into allyl isothiocyanate.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

Stories and the Self

2020 ◽  
Vol 32 (2) ◽  
pp. 47-58 ◽  
Author(s):  
Stefan Krause ◽  
Markus Appel
Keyword(s):  
Meta Analysis ◽  
The Self ◽  
The Other ◽  
Lower Degree ◽  
Contrast Effects ◽  
Self Perception ◽  
Self Perceptions ◽  
Other Hand ◽  
The One ◽  
Implicit And Explicit

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.

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