scholarly journals Role of Molybdate and Other Transition Metals in the Accumulation of Protochelin by Azotobacter vinelandii

2000 ◽  
Vol 66 (4) ◽  
pp. 1580-1586 ◽  
Author(s):  
Anthony S. Cornish ◽  
William J. Page
Keyword(s):  
Metal Ions ◽  
Azotobacter Vinelandii ◽  
The Other ◽  
Binding Potential ◽  
Natural Soil ◽  
Ferric Reductase ◽  
Soil Environment ◽  
High Concentration ◽  
Aerobic Organism

ABSTRACT Both molybdate and iron are metals that are required by the obligately aerobic organism Azotobacter vinelandii to survive in the nutrient-limited conditions of its natural soil environment. Previous studies have shown that a high concentration of molybdate (1 mM) affects the formation of A. vinelandiisiderophores such that the tricatecholate protochelin is formed to the exclusion of the other catecholate siderophores, azotochelin and aminochelin. It has been shown previously that molybdate combines readily with catecholates and interferes with siderophore function. In this study, we found that the manner in which each catecholate siderophore interacted with molybdate was consistent with the structure and binding potential of the siderophore. The affinity that each siderophore had for molybdate was high enough that stable molybdo-siderophore complexes were formed but low enough that the complexes were readily destabilized by Fe3+. Thus, competition between Fe3+ and molybdate did not appear to be the primary cause of protochelin accumulation; in addition, we determined that protochelin accumulated in the presence of vanadate, tungstate, Zn2+, and Mn2+. We found that all five of these metal ions partially inhibited uptake of55Fe-protochelin and 55Fe-azotochelin complexes. Also, each of these metal ions partially inhibited the activity of ferric reductase, an enzyme important in the deferration of ferric siderophores. Our results suggest that protochelin accumulates in the presence of molybdate because protochelin uptake and conversion into its component parts, azotochelin and aminochelin, are inhibited by interference with ferric reductase.

Mechanism of Action of C2H4 in Promoting the Germination of Cocklebur Seeds. III. A Further Enhancement of Priming Effect With Nitrogenous Compounds and C2H4 Responsiveness of Seeds

1996 ◽  
Vol 23 (4) ◽  
pp. 519 ◽  
Author(s):  
M Yoshiyama ◽  
A Maruyama ◽  
T Atsumi ◽  
Y Esashi
Keyword(s):  
Water Stress ◽  
Priming Effect ◽  
Seed Priming ◽  
The Other ◽  
Cyanogenic Glycosides ◽  
High Concentration ◽  
Barnyard Grass ◽  
Nitrogenous Compounds ◽  
Contrary Effect

Efficiency of organic or inorganic osmotica for seed priming of cocklebur (Xanthium pennsylvanicum Wallr.) revealed that KNO3 was the most promising, and was more effective than mannitol or other salts at the same concentration (200 mM) and was independent of the C2H4 action. However, KNO3 applied as a priming reagent enhanced the effect of C2H4 or that of the water stress imposed with mannitol. Unlike the action of mannitol, both KNO3M and C2H4 augmented the pool size of amino acids in seed cells. However, below 50 mM KNO3 imposing no stress only slightly, though insignificantly, affected the germinability as well as the levels of total cyanogen. On the other hand, at a high concentration which imposed water stress on the seeds, 200 mM KNO3 remarkably elevated the contents of both cyanogenic glycosides and lipids in the excised cotyledons. When C2H4 was added with KNO3, the level of cyanogenic compounds significantly increased but when added without KNO3, the contrary effect was shown. Hence the enhancement of the mannitol-induced priming effect by nitrogenous reagents in cocklebur seeds could be implicated in the accumulation of cyanogenic compounds. Unlike cocklebur, both common chickweed and barnyard grass seeds are very responsive to 30 mM KNO3 on germination, and such species abundantly contain cyanogen. The amount of cyanogen was further augmented by contact with KNO3 at only 30 mM. The role of NO-3 -dependent cyanogenesis is highlighted in relation to germination response of seeds.

Reappraisal of the role of turpentine vapor in noncondensible gas explosions

TAPPI Journal ◽  
2010 ◽  
Vol 9 (4) ◽  
pp. 6-11
Author(s):  
RISTO LAUTKASKI
Keyword(s):  
Burning Velocity ◽  
Paper Industry ◽  
High Volume ◽  
The Other ◽  
Air Leakage ◽  
Stoichiometric Mixture ◽  
High Concentration ◽  
Gas Explosions ◽  
Minimal Damage

Turpentine has been identified as the cause of numerous fires and explosions within the pulp and paper industry. Explosions in the noncondensible gas (NCG) collection systems caused by total reduced sulfur (TRS) compounds have usually been minor and caused minimal damage, but explosions caused by turpentine could be catastrophic. When flammable conditions have been created by insufficient dilution, air leakage into the system, or accumulation and breakthrough of TRS gases or turpentine vapor at a chip bin, it is conceivable that turpentine vapor created near-optimum flammable mixtures more often than TRS gases did. In these cases, the burning velocity would have been close to the maximum. On the other hand, when flammable conditions were created due to insufficient dilution of a stream of high volume, low concentration gases (HVLCs) or due to air leakage into a stream of low volume, high concentration gases (LVHCs), then the flammable mixture formed would be expected to have been off-stoichiometric: lean in the former case and rich in the latter case. In both cases, the burning velocity could have been much lower than in the near-stoichiometric mixture. The violence of explosions caused by turpentine is attributed to its capability to form near-stoichiometric mixtures more easily than the other components of NCGs.

scholarly journals Effect of Biochar on the Production of L-Histidine From Glucose Through Escherichia coli Metabolism

2021 ◽  
Vol 8 ◽  
Author(s):  
Yang E ◽  
Jun Meng ◽  
Heqing Cai ◽  
Caibin Li ◽  
Sainan Liu ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Traditional Method ◽  
Organic Molecules ◽  
Lethal Dose ◽  
The Other ◽  
Related Gene ◽  
High Concentration ◽  
E Coli ◽  
Hormone Analogs

The organic compounds from biochar play a role of hormone analogs, stimulating the expression of metabolites by controlling related gene and protein. In this experiment, we reported the L-histidine biosysthesis was promoted by biochar treatment in E. coli unlike genetic engineering of the traditional method. The related results indicated the most optimal concentration was found to be 3%, and 7% is the lethal dose. E. coli was inhibited in the high-concentration treatment. On the other hand, docking technology was usually used as drug screening, basing on Lock-and-key model of protein in order to better understand mechanisms. So the organic compounds of biochar from GC-MS analysis that acted as ligands were connected to HisG protein controlling L-histidine biosysthesis in E. coli. The result showed that the three organic molecules interacted with HisG protein by hydrogen bond. So we considered that these three compounds play regulatory roles in L-histidine biosysthesis, and the hisG gene expression fully supports this conclusion.

Quantitative accuracy of serotonergic neurotrans-mission imaging with high-resolution 123I SPECT

2004 ◽  
Vol 43 (06) ◽  
pp. 185-189 ◽  
Author(s):  
J. T. Kuikka
Keyword(s):  
High Resolution ◽  
Scatter Correction ◽  
Region Of Interest ◽  
Binding Potential ◽  
Partial Volume ◽  
Therapeutic Drugs ◽  
Quantitative Accuracy ◽  
Critical Error ◽  
Statistical Noise

Summary Aim: Serotonin transporter (SERT) imaging can be used to study the role of regional abnormalities of neurotransmitter release in various mental disorders and to study the mechanism of action of therapeutic drugs or drugs’ abuse. We examine the quantitative accuracy and reproducibility that can be achieved with high-resolution SPECT of serotonergic neurotransmission. Method: Binding potential (BP) of 123I labeled tracer specific for midbrain SERT was assessed in 20 healthy persons. The effects of scatter, attenuation, partial volume, mis-registration and statistical noise were estimated using phantom and human studies. Results: Without any correction, BP was underestimated by 73%. The partial volume error was the major component in this underestimation whereas the most critical error for the reproducibility was misplacement of region of interest (ROI). Conclusion: The proper ROI registration, the use of the multiple head gamma camera with transmission based scatter correction introduce more relevant results. However, due to the small dimensions of the midbrain SERT structures and poor spatial resolution of SPECT, the improvement without the partial volume correction is not great enough to restore the estimate of BP to that of the true one.

Plasma Levels of Protein S, Protein C, and Factor X: Effects of Sex, Hormonal State and Age

1995 ◽  
Vol 74 (05) ◽  
pp. 1271-1275 ◽  
Author(s):  
C M A Henkens ◽  
V J J Bom ◽  
W van der Schaaf ◽  
P M Pelsma ◽  
C Th Smit Sibinga ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Postmenopausal Women ◽  
Protein C ◽  
Blood Donors ◽  
Premenopausal Women ◽  
Protein S ◽  
The Other ◽  
Factor X ◽  
Normal Ranges

SummaryWe measured total and free protein S (PS), protein C (PC) and factor X (FX) in 393 healthy blood donors to assess differences in relation to sex, hormonal state and age. All measured proteins were lower in women as compared to men, as were levels in premenopausal women as compared to postmenopausal women. Multiple regression analysis showed that both age and subgroup (men, pre- and postmenopausal women) were of significance for the levels of total and free PS and PC, the subgroup effect being caused by the differences between the premenopausal women and the other groups. This indicates a role of sex-hormones, most likely estrogens, in the regulation of levels of pro- and anticoagulant factors under physiologic conditions. These differences should be taken into account in daily clinical practice and may necessitate different normal ranges for men, pre- and postmenopausal women.

On the role of the dispute between "non-possessors" and "Josephites" in the culture of Moscow's prediction

1998 ◽  
pp. 61-62
Author(s):  
N. S. Jurtueva
Keyword(s):  
The Other ◽  
Moral Transformation ◽  
15Th Century ◽  
The Future ◽  
Secular Power

In the XIV century. centripetal tendencies began to appear in the Moscow principality. Inside the Russian church, several areas were distinguished. Part of the clergy supported the specificobar form. The other understood the need for transformations in society. As a result, this led to a split in the Russian church in the 15th century for "non-possessors" and "Josephites". The former linked the fate of the future with the ideology of hesychasm and its moral transformation, while the latter sought support in alliance with a strong secular power.

From Container to Claustrum: Projective Identification in Couples

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Tamara Feldman
Keyword(s):  
Psychological Health ◽  
Projective Identification ◽  
The Self ◽  
The Other ◽  
Intimate Partners ◽  
And Control ◽  
The Relationship ◽  
As If

This paper is a contribution to the growing literature on the role of projective identification in understanding couples' dynamics. Projective identification as a defence is well suited to couples, as intimate partners provide an ideal location to deposit unwanted parts of the self. This paper illustrates how projective identification functions differently depending on the psychological health of the couple. It elucidates how healthier couples use projective identification more as a form of communication, whereas disturbed couples are inclined to employ it to invade and control the other, as captured by Meltzer's concept of "intrusive identification". These different uses of projective identification affect couples' capacities to provide what Bion called "containment". In disturbed couples, partners serve as what Meltzer termed "claustrums" whereby projections are not contained, but imprisoned or entombed in the other. Applying the concept of claustrum helps illuminate common feelings these couples express, such as feeling suffocated, stifled, trapped, held hostage, or feeling as if the relationship is killing them. Finally, this paper presents treatment challenges in working with more disturbed couples.

Thomas More's “rule” of pleasure before, after, and inUtopia

Moreana ◽  
2017 ◽  
Vol 54 (Number 207) (1) ◽  
pp. 36-56
Author(s):  
Gerard Wegemer
Keyword(s):  
Human Nature ◽  
The Other ◽  
Biblical Allusions ◽  
De Officiis

After establishing a context of More's lifelong engagement with the “calculus” of pleasure, this essay shows how the section devoted to the Utopians' pleasure philosophy is structured around five formulations of a “rule” to calculate “true and honest [honesta]” pleasure in ways that playfully imitate and echo the “rule” Cicero formulates several times in De officiis to discern one's duty when there seems to be a conflict between honestas et utilitas. When followed, the Utopian pleasure calculus shows the necessary role of societas, officii, iustitia, caritas, and the other aspects of human nature, most importantly friendship, that Cicero stresses in his rule and that he argued Epicurus ignored. Much of the irony and humor of this section depends on seeing the predominance of Ciceronian vocabulary in Raphael's unusual defense [patrocinium] of pleasure, rather than a Ciceronian defense of duty rooted in honestas. Throughout, however, this essay also shows how More goes beyond Cicero by including Augustinian and biblical allusions to suggest ways that our final end is not as Epicurus or the Stoics or Cicero claim; the language and allusions of this section point to a level of good cheer and care for neighbors and for God in ways quite different from any classical thinker.

BLOCKADE OF THE SURGE OF PROLACTIN AT PRO-OESTRUS BY ADMINISTRATION OF ANTI-OESTROGENIC SUBSTANCE, MER-25

1973 ◽  
Vol 74 (4) ◽  
pp. 769-774 ◽  
Author(s):  
Akira Yokoyama ◽  
Hiroshi Tomogane ◽  
Katuaki Ôta
Keyword(s):  
Strong Evidence ◽  
The Other ◽  
Other Hand

ABSTRACT A non-steroidal oestrogen antagonist, MER-25, was administered to cycling rats for elucidating the role of oestrogen in the surge of prolactin observed on the afternoon of pro-oestrus (POe). In animals injected with 20 mg of MER-25 intramuscularly on the afternoon (16.30 h) of the first day of dioestrus (D-1), the surge of prolactin was blocked while the level of prolactin on the afternoon of POe of these animals was significantly higher than that of the corresponding controls injected with oil. Ovulation was also blocked in these animals treated with the drug on the afternoon of D-l. On the other hand, treatment on the morning (10.30 h) of the 2nd day of dioestrus failed to prevent not only the surge of prolactin but also ovulation. These observations provide strong evidence for the view that oestrogen is responsible for the surge of prolactin on the afternoon of POe, and that the surge is accompanied by that of LH.

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