scholarly journals Large Scale Dynamics of the Michaelis Complex in Bacillus stearothermophilus Lactate Dehydrogenase Revealed by a Single-Tryptophan Mutant Study

Biochemistry ◽  
2013 ◽  
Vol 52 (11) ◽  
pp. 1886-1892 ◽  
Author(s):  
Beining Nie ◽  
Hua Deng ◽  
Ruel Desamero ◽  
Robert Callender
Keyword(s):  
Lactate Dehydrogenase ◽  
Large Scale ◽  
Bacillus Stearothermophilus

scholarly journals Thermal reaction norms of key metabolic enzymes reflect divergent physiological and behavioral adaptations of closely related amphipod species

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lena Jakob ◽  
Kseniya P. Vereshchagina ◽  
Anette Tillmann ◽  
Lorena Rivarola-Duarte ◽  
Denis V. Axenov-Gribanov ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Lake Baikal ◽  
Enzyme Activities ◽  
Large Scale ◽  
Metabolic Enzymes ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Ecological Niches ◽  
Amphipod Species ◽  
Thermal Plasticity

AbstractLake Baikal is inhabited by more than 300 endemic amphipod species, which are narrowly adapted to certain thermal niches due to the high interspecific competition. In contrast, the surrounding freshwater fauna is commonly represented by species with large-scale distribution and high phenotypic thermal plasticity. Here, we investigated the thermal plasticity of the energy metabolism in two closely-related endemic amphipod species from Lake Baikal (Eulimnogammarus verrucosus; stenothermal and Eulimnogammarus cyaneus; eurythermal) and the ubiquitous Holarctic amphipod Gammarus lacustris (eurythermal) by exposure to a summer warming scenario (6–23.6 °C; 0.8 °C d−1). In concert with routine metabolic rates, activities of key metabolic enzymes increased strongly with temperature up to 15 °C in E. verrucosus, whereupon they leveled off (except for lactate dehydrogenase). In contrast, exponential increases were seen in E. cyaneus and G. lacustris throughout the thermal trial (Q10-values: 1.6–3.7). Cytochrome-c-oxidase, lactate dehydrogenase, and 3-hydroxyacyl-CoA dehydrogenase activities were found to be higher in G. lacustris than in E. cyaneus, especially at the highest experimental temperature (23.6 °C). Decreasing gene expression levels revealed some thermal compensation in E. cyaneus but not in G. lacustris. In all species, shifts in enzyme activities favored glycolytic energy generation in the warmth. The congruent temperature-dependencies of enzyme activities and routine metabolism in E. verrucosus indicate a strong feedback-regulation of enzymatic activities by whole organism responses. The species-specific thermal reaction norms reflect the different ecological niches, including the spatial distribution, distinct thermal behavior such as temperature-dependent migration, movement activity, and mating season.

Site-directed mutagenesis of Bacillus stearothermophilus lactate dehydrogenase

1987 ◽  
Vol 15 (1) ◽  
pp. 152-153 ◽  
Author(s):  
ANTHONY R. CLARKE ◽  
DALE B. WIGLEY ◽  
DAVID A. BARSTOW ◽  
WILLIAM N. CHIA ◽  
ADAM D. B. WALDMAN ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Bacillus Stearothermophilus ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis

Factors Contributing to the Occurrence of Antimicrobial Drug Residues in Kenyan Milk

2004 ◽  
Vol 67 (2) ◽  
pp. 399-402 ◽  
Author(s):  
ANAKALO SHITANDI ◽  
ÅSE STERNESJÖ
Keyword(s):  
Large Scale ◽  
Bacillus Stearothermophilus ◽  
Antimicrobial Drug ◽  
Penicillin G ◽  
Small Scale ◽  
Drug Residues ◽  
Maximum Residue Level ◽  
Antimicrobial Residues ◽  
Field Samples ◽  
The Difference

The study investigated factors contributing to the occurrence of antimicrobial drug residues in milk within four major milk production districts in Kenya. The frequency of contamination was studied among small- and large-scale dairy producers to determine if there were differences between the two types of producers. Field samples (n = 1,600) were analyzed with the improved Dutch tube diffusion test, a microbial inhibitor test ( Bacillus stearothermophilus). In total, 144 and 64 samples from small- and large-scale producers, respectively, were found to contain β-lactam antibiotics at levels exceeding the established Codex maximum residue level for penicillin G (4 μg/kg). The difference in results between the two categories of producers was found to be significant (P < 0.001). To explain the higher frequency of antibiotic contamination of milk from small-scale producers, a questionnaire was constructed and used with 220 randomly selected smallholders in the selected districts. The results suggested (i) lack of understanding of risks related to antibiotic contamination of food, (ii) poor or no treatment records, and (iii) lack of a monitoring system as major risks for contamination. It was concluded that intensification of the education among small-scale dairy producers would greatly reduce the occurrence of antimicrobial residues in milk.

On the effect on specificity of Thr246→Gly mutation in L-lactate dehydrogenase of Bacillus stearothermophilus

1989 ◽  
Vol 161 (1) ◽  
pp. 59-63 ◽  
Author(s):  
Daniel Bur ◽  
Tony Clarke ◽  
James D. Friesen ◽  
Marvin Gold ◽  
Keith W. Hart ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Bacillus Stearothermophilus
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