Some Observations on the Saponin Accumulation in Oat Seedlings and on the Transformation of the Avenacosides to the Antibiotic 26-Desgluco-avenacosides

1982 ◽  
Vol 37 (11-12) ◽  
pp. 1095-1099 ◽  
Author(s):  
Ute Laudenbach ◽  
Jürgen Kesselmeier
Keyword(s):  
Protective Device ◽  
Steroidal Saponins ◽  
Temperature Optimum ◽  
Plastid Development ◽  
Drastic Decrease ◽  
Etiolated Seedlings ◽  
Wide Ph Range ◽  
Ph Range ◽  
Distinct Temperature

Abstract The accumulation of the steroidal saponins avenacoside A and B in oat was investigated in green and etiolated seedlings and was found to be strictly bound to the growth of the seedlings. No significant differences were detected between green and etiolated seedlings, showing that there is no relation between saponin accumulation and plastid development. As the role of the oat saponins has to be seen as a protective device against fungi and bacteria, the transformation of the inactive avenacosides to their corresponding antibiotic 26-desgluco-avenacosides was tested in dependence of pH and temperature. During disruption of leaves, transformation occurs almost completely over a wide pH-range (pH 4 -pH 10); the degree of transformation exhibits no distinct temperature optimum but a drastic decrease at 70 °C.

Role of Persistent Vascular Renin after Bilateral Nephrectomy in Goldblatt-Two Kidney Hypertension

1978 ◽  
Vol 55 (s4) ◽  
pp. 23s-26s ◽  
Author(s):  
H. Thurston ◽  
B. C. Hurst ◽  
R. F. Bing ◽  
J. D. Swales
Keyword(s):  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Bilateral Nephrectomy ◽  
Salt Loading ◽  
Angiotensin System ◽  
Wide Ph Range ◽  
Salt Depletion ◽  
Ph Range ◽  
Aortic Homogenate

1. Aortic homogenate contains renin-like activity which on incubation generates angiotensin I over a wide pH range. 2. Rat aortic renin measured at an incubation pH of 6·5 rose and fell in parallel to plasma renin with salt depletion and salt-loading respectively. Renin measured at an incubation pH of 5·3 showed little relationship with plasma renin. 3. Aortic renin (pH 6·5) was elevated in Goldblatt-two kidney hypertension and slowly fell for 24 h after bilateral nephrectomy whereas the fall in plasma renin was complete by the first hour. Aortic renin (pH 5·3) was also high, but did not fall after bilateral nephrectomy. 4. Aortic renin (pH 6·5) is probably derived from plasma renin whereas renin measured at pH 5·3 is probably a tissue renin. 5. The prolonged half-life of aortic renin (pH 6·5) explains the observation that the renin—angiotensin system appears to be active in maintaining blood pressure for several hours after bilateral nephrectomy whereas the decline in plasma renin is rapid and does not continue significantly beyond 1 h.

A structural perspective on lactoferrin function1This article is part of a Special Issue entitled Lactoferrin and has undergone the Journal's usual peer review process.

2012 ◽  
Vol 90 (3) ◽  
pp. 320-328 ◽  
Author(s):  
Heather M. Baker ◽  
Edward N. Baker
Keyword(s):  
Peer Review Process ◽  
Iron Binding ◽  
Multifunctional Protein ◽  
Wide Ph Range ◽  
Iron Binding Protein ◽  
Productive Research ◽  
Ph Range ◽  
The Many ◽  
And Function

The 3-D structure of human lactoferrin was first solved in atomic detail in 1987. Since that time, a variety of proven and postulated activities have been added to the original annotation of lactoferrin as an iron-binding protein. Structural studies have also expanded to include iron-bound and iron-free (apo) forms, mutants, and the lactoferrins of different species. In this review, we take the current information on both structure and function and show that the 3-D structure provides a useful framework for understanding some activities and also points to productive research directions that could help elucidate other reported functions. Some functions relate to iron binding where the role of lactoferrin is to scavenge and retain iron across a wide pH range. We specifically focus on functions that depend on the surface structure of the molecule, identifying features that may determine the many other protective properties of this multifunctional protein.

RECOVERY OF GERMANIUM BY PRECIPITATION FROM STRONGLY ALKALINE SOLUTION

2020 ◽  
Author(s):  
Andrzej Piotrowicz ◽  
Stanisław Pietrzyk ◽  
Artur Puchała
Keyword(s):  
Alkaline Solution ◽  
Precipitation Process ◽  
Research Material ◽  
Low Concentrations ◽  
Industrial Material ◽  
Industrial Solution ◽  
Wide Ph Range ◽  
Synthetic Solution ◽  
Ph Range

The research material was a strongly alkaline solution containing germanium, lead, arsenic, zinc and trace amounts of other metals, obtained by leaching of industrial material. The aim of the study was to determine the behavior of the above metals in the precipitation process using various acidic agents: HCl, H2SO4, C2H2O4, C6H8O7. The tests were carried out in a wide pH range. The behavior and role of individual ions during the acidification of germanate solution is poorly understood, hence the study of this subject was undertaken. The resulting precipitates and solutions were examined by XRF, XRD and ICP techniques. The recovery yields of individual elements was determined. Attempts were also made to precipitate Ge from a synthetic solution in order to compare the results obtained for the solution of an industrial solution. This research shows that the presence of other ions interferes with the selective recovery of Ge from research solutions. Generally, it can be said that the method of recovery by acidification is effective at low concentrations of the solution's components.

Polarographic and spectrophotometric behaviour of some N-p-phenyl substituted benzamidines

1991 ◽  
Vol 56 (12) ◽  
pp. 2791-2799 ◽  
Author(s):  
Juan A. Squella ◽  
Luis J. Nuñez-Vergara ◽  
Hernan Rodríguez ◽  
Amelia Márquez ◽  
Jose M. Rodríguez-Mellado ◽  
...  
Keyword(s):  
Spectrophotometric Study ◽  
Absorption Bands ◽  
Electrochemical Parameters ◽  
Wide Ph Range ◽  
Group A ◽  
Substituent Constants ◽  
Ph Range ◽  
The Waves

Five N-p-phenyl substituted benzamidines were studied by DC and DP polarography in a wide pH range. Coulometric results show that the overall processes are four-electron reductions. Logarithmic analysis of the waves indicate that the process are irreversible. The influence of the pH on the polarographic parameters was also studied. A UV spectrophotometric study was performed in the pH range 2-13. In basic media some variations in the absorption bands were observed due to the dissociation of the amidine group. A determination of the pK values was made by deconvolution of the spectra. Correlations of both the electrochemical parameters and spectrophotometric pK values with the Hammett substituent constants were obtained.

High degradation efficiency of sulfamethazine with the dual-reaction-center Fe-Mn-SiO2 Fenton-like nanocatalyst in a wide pH range

2021 ◽  
Author(s):  
Manoj Kumar Panjwani ◽  
Qing Wang ◽  
Yueming Ma ◽  
Yuxuan Lin ◽  
Feng Xiao ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Reaction Center ◽  
Degradation Efficiency ◽  
Heterogeneous Fenton ◽  
Wide Ph Range ◽  
Ph Range

The development of a heterogeneous Fenton-like catalyst, possessing high degradation efficiency in a wide pH range, is crucial for wastewater treatment. The Fe-Mn-SiO2 catalyst was designed, and prepared by a...

scholarly journals The Role of the Disulfide Bridge in the Copper (II) Binding by the Cyclic His4-Peptide

2021 ◽  
Vol 22 (12) ◽  
pp. 6458
Author(s):  
Aleksandra Pieniężna ◽  
Weronika Witak ◽  
Aneta Szymańska ◽  
Justyna Brasuń
Keyword(s):  
Metal Ions ◽  
Coordination Mode ◽  
Transition Metal Ions ◽  
Disulfide Bridge ◽  
Chain Flexibility ◽  
Vis Spectroscopy ◽  
Ph Range ◽  
Cd Studies ◽  
Metal Ratios

In this paper, we present studies on the influence of the disulfide bridge on the copper (II) ions’ binding abilities by the cyclic His4-peptide. The studied ligand HKHPHRHC-S-S-C consists of nine amino acids. The cyclic structure was obtained through a disulfide bridge between two cysteinyl groups. Moreover, this peptide is characterized by the presence of four His residues in the sequence, which makes it an interesting ligand for transition metal ions. The potentiometric and spectroscopic (UV-Vis spectroscopy and circular dichroism spectroscopy (CD)) studies were carried out in various molar ligand to metal ratios: 2:1, 1:1, and 1:2, in the pH range of 2.5–11 at 25 °C. The results showed that the cyclic His4-peptide promotes dinuclear complexes in each of these systems and forms the final dinuclear species with the {NIm, 3N-amide}{NIm, 3N-amide} coordination mode. The obtained data shows that cyclization by the formation of the disulfide bond has an impact on the peptide chain flexibility and appearance of additional potential donors for metal ions and influences the copper (II) ions’ coordination.

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