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.

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.

An improved separation scheme for Sr through fluoride coprecipitation combined with a cation-exchange resin from geological samples with high Rb/Sr ratios for high-precision determination of Sr isotope ratios

2020 ◽  
Vol 35 (5) ◽  
pp. 953-960
Author(s):  
Wen-Gang Liu ◽  
Shuang Wei ◽  
Jian Zhang ◽  
Cong Ao ◽  
Fu-Tian Liu ◽  
...  
Keyword(s):  
Cation Exchange ◽  
High Precision ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Separation Scheme ◽  
Geological Samples ◽  
Sr Isotope ◽  
Precision Determination ◽  
High Precision Determination

A new separation method for Sr involving HF coprecipitation combined with AG50 resin from samples with high Rb/Sr ratios.

Ion Exchange Method for Rapid Determination of Alkalinity of Water-Soluble Tea Ash Containing High Levels of Manganese

1980 ◽  
Vol 63 (3) ◽  
pp. 460-461
Author(s):  
Saidul Z Qureshi ◽  
Fadhil M Najib ◽  
Fahmi A Mohammed
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Exchange Resin ◽  
Rapid Determination ◽  
Cation Exchange Resin ◽  
Water Soluble ◽  
Exchange Method ◽  
Strong Cation Exchange ◽  
Ion Exchange Method

Abstract An ion exchange method to determine the alkalinity of water-soluble tea ash containing high levels of manganese is described. A chromatographic column containing a strong cation exchange resin (20–50 mesh) in Na+ form, with a bed volume of 5 mL is used. The present ion exchange method is compared to pH titrations and also to the official AOAC methods (31.012, 31.015, 31.016). Results with the new method are accurate and precise.

Analysis of Sodium Diphenylhydantoin and Phenobarbital Combinations by Nonaqueous Titration

1968 ◽  
Vol 51 (5) ◽  
pp. 1013-1016
Author(s):  
Sura J P Agarwal ◽  
Martin I Blake
Keyword(s):  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Ammonium Hydroxide ◽  
Butyl Alcohol ◽  
Dosage Forms ◽  
Direct Titration ◽  
Titration Procedure ◽  
Tert Butyl Alcohol ◽  
Preliminary Separation

Abstract A simple, nonaqueous titration procedure is described for the determination of sodium diphenylhydantoin and phenobarbital combinations. Preliminary separation of the components is unnecessary. The phenobarbital content is determined by direct titration in tert.-butyl alcohol, using sodium methoxide or triethyl n-butyl ammonium hydroxide as the titrant. The total acidity is determined by titration of the sample after passage through a cation exchange resin (Amberlite IRC-50). The sodium diphenylhydantoin content is obtained by difference. Quantitative recoveries were obtained for synthetic mixtures and commercially available dosage forms

Simultaneous Analysis of Nivalenol and Deoxynivalenol in Cereals by Liquid Chromatography

1987 ◽  
Vol 70 (3) ◽  
pp. 479-483 ◽  
Author(s):  
Denis R Lauren ◽  
Roy Greenhalgh
Keyword(s):  
Liquid Chromatography ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Relative Standard ◽  
Phase Liquid ◽  
Cereal Samples ◽  
Sensitive Method

Abstract A sensitive method is described for determination of nivalenol (NIV) and deoxynivalenol (DON) in cereals by using reverse phase liquid chromatography and UV detection at 222 nm. The sample is extracted with acetonitrile-water (85 + 15) and an aliquot is purified by passage through a combined column of cation exchange resin and alumina-carbon (20 + 1). Analysis at this stage is possible with some samples but the method recommends passing an aliquot through a carbon minicolumn after evaporation and solubilization in methanol. Interference from coextracted compounds at this point is negligible. Recoveries of both NIV and DON from spiked extracts taken through the full method were in the range 83-94%. The relative standard deviation, based on 5 replicate determinations from each of 2 corn samples, was approximately 5% for both NIV and DON. With a 10 fiL injection, the minimum contamination (3 x signal/noise ratio) able to be detected in cereal samples was about 0.015 μ NIV/g and 0.05 μ DON/g. The cleaned up extracts are also suitable for analysis by gas chromatography.

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