Low temperature effect on production of ampicillin and cephalexin in ethylene glycol medium with immobilized penicillin acylase

2006 ◽  
Vol 41 (9) ◽  
pp. 1924-1931 ◽  
Author(s):  
Carolina Aguirre ◽  
Paola Opazo ◽  
Mineri Venegas ◽  
Ruby Riveros ◽  
Andrés Illanes
Keyword(s):  
Low Temperature ◽  
Ethylene Glycol ◽  
Temperature Effect ◽  
Penicillin Acylase ◽  
Immobilized Penicillin Acylase

Optimization of 6-aminopenicillanic acid (6-APA) production by using a new immobilized penicillin acylase

2000 ◽  
Vol 32 (3) ◽  
pp. 173 ◽  
Author(s):  
Jesús Torres-Bacete ◽  
Miguel Arroyo ◽  
Raquel Torres-Guzmán ◽  
Isabel de la Mata ◽  
María Pilar Castillón ◽  
...  
Keyword(s):  
Penicillin Acylase ◽  
Immobilized Penicillin Acylase

Low-Temperature Liquid-Phase Synthesis and Electrochemical Activity of α-Nickel Hydroxide with Flower-Like Micro-/Nano-Structure

2011 ◽  
Vol 347-353 ◽  
pp. 3379-3383
Author(s):  
Zhi Wei Li ◽  
Xu Xiang ◽  
Zong Min Tian
Keyword(s):  
Liquid Phase ◽  
Low Temperature ◽  
Ethylene Glycol ◽  
Nickel Hydroxide ◽  
Variable Temperature ◽  
Mixed Solvents ◽  
Reaction Medium ◽  
Electrochemical Activity ◽  
Nano Structure ◽  
Pure Phase

The synthesis of α-nickel hydroxide has been achieved via a facile liquid-phase precipitation approach, using the mixed solvents of ethylene glycol and water as reaction medium at low temperature. The XRD characterization indicates that pure phase α-Ni(OH)2can be obtained under variable temperature and pH value. The products present a flower-like micro-/nano-structure assembled with curved nanosheets. The nanosheets have the width of 100~500 nm and the thickness of 20~70 nm. The cavities are formed in the structure due to the interconnection of curved nanosheets. The solvents play a key role in the formation of Ni(OH)2with different forms. Pure phase α-Ni(OH)2can only be synthesized in the mixed solvents of ethylene glycol and water. Cyclic voltammetry was applied to test the electrochemical activity of the as-synthesized α-Ni(OH)2. The findings suggest that the α-Ni(OH)2with a micro-/nano-structure exhibits excellent electrochemical activity, which may be considered as a promising candidate of electrode material.

Luminescence Studies on Low Temperature Synthesized ZnGa2O4:Ln3+ (Ln = Tb and Eu) Nanoparticles

2008 ◽  
Vol 8 (11) ◽  
pp. 5776-5780 ◽  
Author(s):  
C. Manikyala Rao ◽  
V. Sudarsan ◽  
R. S. Ningthoujam ◽  
U. K. Gautam ◽  
R. K. Vatsa ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Oleic Acid ◽  
Steady State ◽  
Low Temperature ◽  
Ethylene Glycol ◽  
Urea Hydrolysis ◽  
Lanthanide Ions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Broad Emission

ZnGa2O4 nanoparticles doped with lanthanide ions (Tb3+ and Eu3+) were prepared at a low temperature of 120 °C based on urea hydrolysis in ethylene glycol medium. X-ray diffraction studies have confirmed that strain associated with nanoparticles changes as Tb3+ gets incorporated in the ZnGa2O4 lattice. Based on steady state emission and excitation studies of ZnGa2O4:Tb nanoparticles, it has been inferred that ZnGa2O4 host is characterized by a broad emission around 427 nm and there exists energy transfer between the host and Tb3+ ions. Unlike this, for ZnGa2O4:Eu nanoparticles, very poor energy transfer between the host and Eu3+ ions is observed. These nanoparticles when coated with ligands like oleic acid results in their improved dispersion in organic solvents like chloroform and dichloromethane.

scholarly journals GENETIC EVIDENCE FOR INTERACTION BETWEEN NONHOMOLOGOUS PROTEINS IN YEAST AND A CASE OF SUPPRESSION AT THE HIS1 LOCUS

Genetics ◽  
1980 ◽  
Vol 94 (2) ◽  
pp. 327-339 ◽  
Author(s):  
Richard Snow
Keyword(s):  
Enzyme Activity ◽  
Low Temperature ◽  
Enzymatic Activity ◽  
Temperature Effect ◽  
Conformational Change ◽  
Minimal Medium ◽  
Genetic Evidence ◽  
Structural Genes ◽  
Wild Type ◽  
Is Strain

ABSTRACT The HIS1 and THR4 loci are the structural genes for phosphoribosyl-ATP pyrophosphorylase and threonine synthetase, respectively. The allele his1-IS has no enzyme activity at 30", but does have activity at 15" provided the cell contains the wild-type THR4 allele or a suppressing allele at another locus, designated SUP(his1-1S). Under these conditions, cells with the hisl-IS mutation are capable of growth on minimal medium at 15". Three kinds of reversions of a hisl-IS thr4 sup(his1-IS) strain to histidine prototrophy have been obtained: (1) his1-IS locus reversions to HIS1 that restore growth without added histidine at 30", (2)  thr4 reversions to THR4 that simultaneously eliminate the requirement for threonine and restore the low-temperature effect on the his1-IS allele, and (3)mutations from sup to SUP. The SUP allele is not an ochre suppressor, and it is not linked to either HISI, THR4 or a centromere. It may represent a missense suppressor. I t is proposed that the effect ofTHR4 is caused by aggregation of the wild-type threonine synthetase with defective his1-IS monomers, causing a favorable conformational change in the histidine protein that restores limited enzymatic activity. This can be regarded as a case of complementation between nonhomologous proteins.

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