scholarly journals ROLE OF ELECTROLYTES AND STARVATION IN ALTERING APPARENT RADIOSENSITIVITY OF BAKERS' YEAST

1955 ◽  
Vol 38 (4) ◽  
pp. 493-504 ◽  
Author(s):  
William J. Bair ◽  
J. N. Stannard
Keyword(s):  
Cation Exchange ◽  
Colony Formation ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Complete Inhibition ◽  
Co2 Production ◽  
X Rays ◽  
Marked Inhibition ◽  
Resin Treatment

1. Respiration and fermentation of yeast receiving 90,000 r of 250 kv. x-rays were studied under a variety of conditions. This dose will nearly completely inhibit growth or colony formation. 2. The apparent effects of irradiation are quite dependent on the K+ and H+ of the suspending medium. At pH 4.5 stimulatory effects were observed in KH2PO2 buffer and inhibition in potassium-free (T-S-T) buffer. At pH 6.5 the situation was reversed and the effects were very small (about 10 per cent). Addition of K+ to irradiated yeast in T-S-T buffer at pH 4.5 can completely reverse the inhibition seen. 3. Starving increases the apparent radiosensitivity of respiration and fermentation, probably by depletion of metabolite and/or electrolyte reserves. 4. Treatment with a cation exchange resin (dowex 50) results in marked inhibition of these processes in irradiated yeast, either fresh or starved. This was most effective if given after irradiation. Almost complete inhibition of anaerobic CO2 production occurs with starvation, irradiation, and dowex treatment combined. 5. The effects of starvation and cation exchange resin treatment can be reversed, though not completely, by adding K+ to the medium.

Preliminary study of the effect of cation-exchange resin treatment on the aging of tempranillo red wines

LWT ◽  
2021 ◽  
Vol 138 ◽  
pp. 110669
Author(s):  
A.M. Mislata ◽  
M. Puxeu ◽  
E. Nart ◽  
S. de Lamo ◽  
R. Ferrer-Gallego
Keyword(s):  
Cation Exchange ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Red Wines ◽  
Preliminary Study ◽  
Resin Treatment

scholarly journals EFFECT OF STARVING AND DOWEX 50 TREATMENT ON GROWTH OF NORMAL AND X-IRRADIATED YEAST

1955 ◽  
Vol 38 (4) ◽  
pp. 505-513 ◽  
Author(s):  
William J. Bair ◽  
J. N. Stannard
Keyword(s):  
Colony Formation ◽  
Exchange Resin ◽  
Metabolic Response ◽  
Cation Exchange Resin ◽  
X Rays ◽  
Growth Responses ◽  
Inhibition Of Growth ◽  
Effects Of Radiation ◽  
Temporary Inhibition

1. Effects of starvation or treatment with a cation exchange resin, dowex 50, parallel in some respects those seen earlier on the respiration and fermentation of bakers' yeast receiving 90,000 r of 250 kv. x-rays. Starvation increased the radiosensitivity of cell division processes whether measured by colony formation or by turbidimetric determination of growth in a liquid medium. The dowex 50 enhanced the radiation effect by the latter measure but appeared to increase colony formation of irradiated yeast. 2. The effects on growth differ from those on respiration and fermentation in that the exchange resin treatment did not inhibit colony formation further, and neither starvation nor resin appreciably altered the growth of non-irradiated yeast. 3. Two effects of radiation are seen in these experiments: (a) a permanent inhibition of growth, and (b) a temporary inhibition of the remaining cells resulting in delay of growth. 4. The irradiated cell is more dependent on certain aspects of its environment in terms of growth responses as well as in terms of metabolism (i.e. respiration and fermentation). Whether or not potassium plays a role in the growth response as it does in the metabolic response cannot be ascertained from the present data.

Synthesis of 3,4-Dihydropyrano[c]chromenes Using Carbon Microsphere Supported Copper Nanoparticles (Cu-NP/C) Prepared from Loaded Cation Exchange Resin as a Catalyst

2019 ◽  
Vol 16 (2) ◽  
pp. 288-293
Author(s):  
Yogesh W. More ◽  
Sunil U. Tekale ◽  
Nitishkumar S. Kaminwar ◽  
László Kótai ◽  
Tibor Pasinszki ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Cation Exchange ◽  
Copper Nanoparticles ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Environmentally Benign ◽  
High Yield ◽  
Carbon Microsphere ◽  
Catalytic Material ◽  
Operational Simplicity

Aim and Objective: The present study was performed with the aim to develop an efficient and environmentally benign protocol for the synthesis of biologically siginifcant 3, 4-dihydropyrano[c]chromenes using a new catalytic material. The protocol involves the use of a reusable, environment friendly materials and solvents with operational simplicity. Materials and Methods: Carbon microsphere supported copper nanoparticles (Cu-NP/C) prepared from loaded cation exchange resin were synthesized, characterized with well versed analytical techniques such as XRD, SEM and Raman spectroscopy and the synthesized material was used as a catalyst for the environmentally benign synthesis of 3,4-dihydropyrano[c]chromenes. Results: The formation of carbon microsphere supported copper nanoparticles (Cu-NP/C) prepared from loaded cation exchange resin was confirmed by XRD, SEM and Raman spectroscopy which was employed as a heterogeneous material for the synthesis of 3,4-dihydropyrano[c]chromenes. The products formed were characterized by the analysis of spectroscopic data - NMR, IR and mass. The safe catalytic system offers several advantages including operational simplicity, environmental friendliness, high yield, and reusability of catalyst and green chemical transformation. Conclusion: Herein we report an easy and efficient protocol for the one-pot synthesis of dihydropyrano[ c]chromenes using environmentally benign MCR approach in ethanol as the green solvent. The method developed herein constitutes a valuable addition to the existing methods for the synthesis of titled compounds.

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