Melibiose

About: Melibiose is a research topic. Over the lifetime, 1002 publications have been published within this topic receiving 27300 citations. The topic is also known as: Melibiose.

Control of Synthesis of Malate Dehydrogenase in Aerobacter aerogenes

Abstract: An inverse linear relationship was observed between the levels of l-malate dehydrogenase (MDH) and growth rates of Aerobacter aerogenes when grown under aerobic and anaerobic conditions on various substrates which served as the sole carbon and energy sources. Deviations from this linearity were found. MDH levels of cells grown aerobically on oxalacetate, l-malate, d-mannose and d-galactose, and of cells grown anaerobically on l-malate and d-mannose were higher than those expected according to this relationship. Enzyme levels of cells grown aerobically on maltose, d-glucuronate, pyruvate, and possibly melibiose and sucrose were lower than the expected ones. Experiments in which the cells were grown on a mixture of two substrates showed that substrates which gave low levels of MDH repressed the synthesis of this enzyme even in the presence of l-malate or other “high-level substrates.” Repressed levels were also observed when the mixture contained l-malate together with “intermediate” or high-level substrates. Identical MDH patterns were obtained by acrylamide gel electrophoresis for all the enzymatic preparations.

Kinetics of Hydrolyses of Sorghum Molasses with Dilute Mineral Acids and Oxalic Acid and Melibiose with Oxalic Acid

Abstract: Investigations were carried out on the kinetics of hydrolyses of sorghum molasses with dilute mineral acids and oxalic acid and melibiose with oxalic acid at relatively high temperatures. Kinetic equations for hydrolysis of sorghum molasses and melibiose have been derived from the experimentally determined hydrolysis rate constants as functions of the acid concentration and temperature. It has been shown that the hydrolysis activity of oxalic acid is weaker than those of hydrochloric and sulfuric acid, and that the second hydrogen atom in oxalic acid does not significantly participate in hydrolysis.

Public-good driven release of heterogeneous resources leads to genotypic diversification of an isogenic yeast population in melibiose.

Abstract: Adaptive diversification of an isogenic population, and its molecular basis has been a subject of a number of studies in the last few years. Microbial populations offer a relatively convenient model system to study this question. In this context, an isogenic population of bacteria (E. coli, B. subtilis, and Pseudomonas) has been shown to lead to genetic diversification in the population, when propagated for a number of generations. This diversification is known to occur when the individuals in the population have access to two or more resources/environments, which are separated either temporally or spatially. Here, we report adaptive diversification in an isogenic population of yeast, S. cerevisiae, when propagated in an environment containing melibiose as the carbon source. The diversification is driven due to a public good, enzyme α-galactosidase, leading to hydrolysis of melibiose into two distinct resources, glucose and galactose. The diversification is driven by a mutations at a single locus, in the GAL3 gene in the GAL/MEL regulon in the yeast.

STABILITY OF NATIVE AND MODIFIED α-GALACTOSIDASE OF Cladosporium cladosporioides.

Abstract: By modifying carbohydrate component of glycoproteins it is possible to elucidate its role in manifestation of structural and functional properties of the enzyme. The comparison of activity and stability of the native and modified by oxidation with sodium periodate α-galactosidase of Cladosporium cladosporioides was carried out. To determine α-galactosidase activity the authors used n-nitrophenyl synthetic substrate, as well as melibiose; raffinose and stachyose. Modification of the carbohydrate component had a significant effect on catalytic properties of the enzyme. Both the reduction of V and enzyme affinity for natural and synthetic substrates were observed The native enzyme retained more than 50% ofthe maximum activity in the range of 20-60 °C, while for the modified enzyme under the same conditions that temperature range was 30-50 °C. The modified α-galactosidase demonstrated a higher thermal stability under neutral pH conditions. The residual activity of the modified α-galactosidase was about 30% when treated with 70% (v/v) methanol, ethanol and propanol. About 50% of initial activity was observed when 40% ethanol and propanol, and 50% methanol were used. It was shown that the modification of C. cladosporioides α-galactosidase by sodium periodate is accompanied by a significant decrease in enzyme activity and stability, probably caused by topological changes in the tertiary and quaternary structure of the protein molecule.

Retracted Article: Isolation of Lactobacillus Species from Domestic Dairy Products of Mahabad City

Abstract: Background: Lactobacillus is the most important group of lactic acid bacteria that produce acid lactic through fermentation of glucose, which is an important process in dairy production. Due to the natural microbic ecosystems of milk, the traditional dairy products provide a suitable culture for growth and proliferation of Lactobacillus strains. Objectives: The aim of this study was to investigate Lactobacillus species from domestic dairy products of Mahabad city. Methods: In this study, 90 samples of cheese, yogurt, and dough were collected from the nearby villages of Mahabad. For the isolation of Lactobacillus, samples were cultured in MRS agar and grown colonies were tested gram stain, catalase test, and morphology. Catalase-negative, gram positive, and without spores bacillus identification and purification. Then, oxidase tests, reduce nitrate, and oxidation-reduction was performed on the SIM medium. To identify species of Lactobacillus, growth in 15°C - 45°C, gas production from glucose with Durham tube to detect homo or hetero Fermentative, and fermentation Fructose, Maltose, Lactose, Galactose, Mannose, Ribose, Arabinose, Xylose, Cellobiose, Inositol, Mannitol, Melezitose, Melibiose, Raffinose, Rhamnose, Trehalose, Salicin, Glycerol and Gluconate and esculin hydrolysis were studied. Results: In 3 products, Lactobacillus plantarum strain was identified, which was in cheese (46%) in comparison with yogurt and dough (respectively 13% and 36%). Conclusions: Based on findings in this study, Cheese provides better culture for growth and proliferation of Lactobacillus when compared with yogurt and dough and the Lactobacillus plantarum strain was the most of milk microflora and traditional dairy products of Mahabad town.