Aflatoxin is degraded at different temperatures and pH values by mycella of Aspergillus parasiticus

1978 ◽  
Vol 6 (1) ◽  
pp. 95-100 ◽  
Author(s):  
M. P. Doyle ◽  
E. H. Marth
Keyword(s):  
Aspergillus Parasiticus ◽  
Ph Values ◽  
Different Temperatures

Characterization and Control of Erwinia spp. and Pluralibacter sp. in Tuna Salad Preparations

2019 ◽  
Vol 82 (6) ◽  
pp. 1071-1081
Author(s):  
KRISTIN BJORNSDOTTIR-BUTLER ◽  
SUSAN McCARTHY ◽  
RONALD A. BENNER
Keyword(s):  
Growth Conditions ◽  
Whole Genome ◽  
Processing Conditions ◽  
Optimum Growth ◽  
Significant Growth ◽  
Ph Values ◽  
Histamine Production ◽  
Different Temperatures ◽  
And Control ◽  
Erwinia Persicina

ABSTRACT Histamine-producing Erwinia and Pluralibacter spp. capable of producing toxic histamine levels were isolated from ingredients commonly used in tuna salad preparations. The characterization and control of these histamine-producing bacteria are necessary to prevent illness from tuna salad consumption. We confirmed the identity of two Erwinia spp. and one Pluralibacter sp. previously isolated from tuna salad ingredients through whole genome sequencing and phylogenic analysis and characterized them for growth and histamine production at different temperatures, pH values, and salt concentrations. In addition, we examined the effects of dried vinegar (DV) powder on growth and histamine production of these strains in inoculated tuna salad preparations. Optimum growth temperatures in tryptic soy broth (TSB) for the two Erwinia spp. and one Pluralibacter sp. were 30.1, 31.1, and 33.9°C, respectively, and growth in TSB was observed at 5°C for both genera. Optimum histamine production of Erwinia persicina, Erwinia spp., and Pluralibacter spp. in TSB with histidine occurred from 25 to 30°C, pH 4 to 6, and 0 to 4% NaCl. No significant growth or histamine production was observed in tuna salad preparations stored at 4°C. Growth and histamine production by Erwinia or Pluralibacter spp. was inhibited in tuna salad containing celery and onion and 2% DV, whereas significant growth and histamine production occurred in tuna salad without DV. Understanding optimum growth conditions and histamine production can provide guidance to tuna salad manufacturers in formulating products and adjusting processing conditions that minimize hazards from these histamine-producing bacteria. Addition of 2% DV to tuna salad preparations may prevent histamine production in the event of temperature abuse. HIGHLIGHTS

scholarly journals Thermodynamic Investigations on the Inclusion Complexation of Piroxicam with Cyclodextrin Derivatives

2005 ◽  
Vol 73 (3) ◽  
pp. 147-161 ◽  
Author(s):  
Charumanee S. ◽  
Weiss-Greiler P. ◽  
Wolschann P. ◽  
Viernstein H. ◽  
Titwan A. ◽  
...  
Keyword(s):  
Ph Value ◽  
Equilibrium Constants ◽  
Inclusion Complexation ◽  
Solubility Diagram ◽  
Phase Solubility ◽  
Cyclodextrin Derivatives ◽  
Ph Values ◽  
Solubility Behavior ◽  
Solubility Method ◽  
Different Temperatures

Thermodynamic studies of piroxicam in aqueous solution complexed with β-cyclodextrin (β-CD), γ-cyclodextrin (γ-CD) and two β-cyclodextrin derivatives, hydroxypropyl-β-cyclodextrin (HP-P-CD) and methyl-β-cyclodextrin (Me-β-CD) were performed at different temperatures and pH values using the phase solubility method. The phase solubility diagrams of β-CD, γ-CD and HP-β-CD is of AL-type behavior, indicating the formation of 1:l complexes. The related stability constants range from β-CD > γ-CD > Me-β-CD > HP-β-CD, respectively. An Ap-type solubility diagram is observed for Me-β-CD, indicating the formation of 1:2 complexes at higher CD concentrations. From the temperature dependence of the equilibrium constants the reaction enthalpies and entropies have been determined. The contributions of the reaction entropies are small and no enthalpy-entropy-compensation is observed, except for γ-CD, where a very small negative reaction entropy could be estimated. Moreover, the influence of the pH value is rather high because the differently charged forms of piroxicam show different solubility behavior in water.

Preliminary Study on the Removal of Hexavalent Chromium in Wastewater with Reduction of Sulfur Dioxide

2013 ◽  
Vol 864-867 ◽  
pp. 1699-1703
Author(s):  
Ji Ming Wu ◽  
Sheng Gao Cheng
Keyword(s):  
Reaction Time ◽  
Sulfur Dioxide ◽  
Hexavalent Chromium ◽  
Reduction Reaction ◽  
High Concentration ◽  
Reaction Conditions ◽  
Ph Values ◽  
Different Temperatures ◽  
Preliminary Study ◽  
High Concentrations

The paper focused on a self-developed methodology through using sulfur dioxide to deal with high concentration of chromium-containing wastewater. It studied the effects of different pH values, different reaction time, different temperatures and different amounts of sulfur with sulfur dioxide reduction reaction on the chromium-containing wastewater. The results showed that: when the reaction conditions were controlled as follows: the pH values ranged from 2 to 4, the reaction temperature was controlled 40~60°C, the amount of sulfur in theoretical was 1.2 times and the reaction time was 40 min, the hexavalent chromium in the high concentrations of chromium-containing wastewater could be effectively removed.

Bentonite Interaction with Saline High-pH Solutions

2012 ◽  
Vol 1475 ◽  
Author(s):  
Heikola Tiina ◽  
Vuorinen Ulla
Keyword(s):  
Cementitious Materials ◽  
Buffering Capacity ◽  
Ongoing Research ◽  
High Ph ◽  
Ph Values ◽  
Safety Function ◽  
Bentonite Buffer ◽  
Different Temperatures ◽  
Leaching Solution ◽  
In The Beginning

ABSTRACTDegradation of cementitious materials produces leachates of high pH. Such an alkaline plume, if reaching the bentonite buffer, is likely to induce mineralogical and chemical changes in bentonite over long times and may jeopardise the set safety function of the buffer.The objective of this ongoing research is to study the possible alterations of two bentonites, MX-80 and Deponit CA-N, in alkaline leachates at two different temperatures. Also the buffering capacity of the bentonites against high pH will be evaluated.The ongoing batch experiments are carried out in an anaerobic glove-box (Ar atmosphere, low CO2) at two temperatures (25/60 °C) with three types of simulated cement waters (pH 9.7/9,3, 11.3/10.2 and 12.0/10.9) at 25/0 °C) and one saline groundwater simulate (pH 8.3/7.9) as reference. The solid to liquid ratio used is 1/10. For each set of experiments there are three parallels so that bentonite alteration can be analysed after three different time periods. In the experiment each bentonite sample is leached with several batches of leaching solution. For each renewal of the leaching solution the phases are separated by centrifugation, the reacted solution withdrawn and the chemical composition analysed.The high-pH experiments (11.3 and 12.0, at 25°C) have continuously shown an initial decrease in the pH-values after each leachate renewal, albeit less dramatic than in the beginning, indicating remaining buffering capacity of the bentonites. The other two experiments (pH 8.3 and 9.7 at 25°C) have shown rather unaltered pH-values. In general, slightly lower pH-values were observed in the Deponit CA-N samples than in those of MX-80. The main cations (Na and Ca) analysed in the leachates have shown a rather expected trends as a result of ion-exchange occurring in the bentonites. The analysed Si concentrations indicate possible dissolution of smectite. More conclusions are possible after the bentonites have been characterized. One experimental set of the 25 °C experiments has been finished and the bentonite phases are being characterized. Other experiment sets are still continued.

Stability of Paramecin 34 at Different Temperatures and pH Values

Science ◽  
1957 ◽  
Vol 126 (3285) ◽  
pp. 1243-1244 ◽  
Author(s):  
R. W. DORNER
Keyword(s):  
Ph Values ◽  
Different Temperatures

EFFECTS OF X-RADIATION AND OF METABOLIC INHIBITORS ON RAT THYMOCYTES IN VITRO

1962 ◽  
Vol 40 (11) ◽  
pp. 1535-1552 ◽  
Author(s):  
D. K. Myers ◽  
Donna E. DeWolfe ◽  
Kimiko Araki
Keyword(s):  
Oxygen Consumption ◽  
Normal Cell ◽  
Cell Metabolism ◽  
Metabolic Inhibitors ◽  
Low Doses ◽  
Ph Values ◽  
Atp Levels ◽  
Different Temperatures ◽  
High Doses

The survival of X-irradiated thymocytes in vitro was studied after incubation for various periods of time and at different pH values as well as at different temperatures. Death at 25 °C following exposure to high doses of X-radiation may be due to the liberation of destructive enzymes. The effects of high doses could be largely prevented by addition of nicotinamide after irradiation.The cause of cell death at 37 °C following exposure to low doses of X-radiation is still uncertain. Some metabolic inhibitors also showed a considerable difference in their toxicity to thymocytes at 37 °C and at 25 °C. Dinitrophenol, for example, was highly toxic at 37 °C but almost ineffective in killing cells at 25 °C, even though it produced similar decreases in ATP levels at both temperatures. The marked difference in survival of irradiated thymocytes at 37 °C and at 25 °C could therefore be explained if low doses of X-radiation interfered with the normal cell metabolism. However, low doses of radiation, unlike dinitrophenol, did not produce any immediate decrease either in ATP levels or in oxygen consumption of thymocyte suspensions.

Solubility of egg white proteins: Effect of pH and temperature.

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Maria Thereza Moraes Santos Gomes ◽  
Daniela Helena Guimarães Pelegrine
Keyword(s):  
Functional Properties ◽  
Protein Solubility ◽  
Egg White ◽  
Effect Of Ph ◽  
Ph Changes ◽  
Egg White Protein ◽  
Ph Values ◽  
Egg White Proteins ◽  
Different Temperatures ◽  
Integrated Study

Abstract Effects of different temperatures and pH values on the solubility of egg white proteins were studied. The solubility was determined experimentally in the temperature range of 40 to 100°C, and pH of 7.5 and 9.0. Morr et al (1985) and Bradford (1976) methods were used to determine the solubility and the results were compared. The results showed that the solubility of egg white protein was influenced by pH as well as temperature. The integrated study provided valuable information for dried egg white protein solubility analysis. Temperature and pH changes alter the solubility of egg white proteins and consequently both temperature and pH influences in functional properties. Besides, it was also observed an interaction among the temperature and pH on egg white proteins solubility. The minimum solubility values were achieving at 60°C, indicating possible protein coagulation from this temperature.

scholarly journals Amino ketone synthesis in avian erythrocytes

1969 ◽  
Vol 114 (3) ◽  
pp. 499-507 ◽  
Author(s):  
R. A. Dale
Keyword(s):  
Pyridoxal Phosphate ◽  
Tris Buffer ◽  
Amino Ketone ◽  
Ph Values ◽  
Freeze Dried ◽  
Avian Erythrocytes ◽  
Different Temperatures ◽  
Metabolic Significance

1. The relative rates of synthesis of aminolaevulate and aminoacetone by particles prepared from avian erythrocytes were measured under various conditions. 2. The production of both amino ketones by fresh particles was about three times greater in anaemia caused by phenylhydrazine and acetylphenylhydrazine than in anaemia caused by removal of 20–30ml. of blood. 3. The synthesis of aminolaevulate by freeze-dried particles decreased more than that of aminoacetone in the absence of added pyridoxal phosphate, in the presence of cyanide and of tris buffer, and after preincubation of the erythrocyte particles. Other differences in the rates of synthesis of the two amino ketones were observed after (a) incubation of particles at different temperatures and (b) storage of homogenized freeze-dried particles at different pH values. 4. It is suggested that these differences in the production of the two amino ketones are due to the presence of two amino ketone synthetases or to two or more isoenzymes of aminolaevulate synthetase. 5. The metabolic significance of aminoacetone in erythrocytes is discussed.

Heat-induced changes in sulphydryl and disulphide levels of β-lactoglobulin A and the formation of polymers

1976 ◽  
Vol 43 (3) ◽  
pp. 411-418 ◽  
Author(s):  
K. Watanabe ◽  
H. Klostermeyer
Keyword(s):  
Heat Treatment ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Exchange Reactions ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Ph Values ◽  
Different Temperatures ◽  
Induced Changes ◽  
Β Lactoglobulin

SummaryThe effects of heat and pH on sulphydryl (–SH) and disulphide (–SS–) groups of β-lactoglobulin (β-lg) A have been studied by heating at different temperatures and pH values in air and at pH 6·9 in the absence of air. At pH 6·9 under aerobic conditions a decrease of –SH groups and an increase of –SS– groups was observed with increasing time and temperature. Only small changes were found under anaerobic conditions. At pH from 3·0 to 9·8 the –SH level decreased while the –SS– level increased up to pH 6·9 and then dropped rapidly. In addition to –SH/–SS– interchange there were reactions to other sulphur-containing compounds as seen from the losses in the total amount of –SH plus –SS– sulphur. The results of gelchromatographic investigations suggest that –SH-initiated –SS– exchange-reactions play an important role in the formation of high molecular weight polymers of β-lg A during heat treatment, and that the formation of intermediates depends on the presence of air.

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