scholarly journals Investigation of Optimum pH and Temperature for In-Vitro Crystallization of Urinary Cystine

2019 ◽  
Vol 6 (1) ◽  
pp. 25
Author(s):  
A. D. U. R. Gunawardana ◽  
K. N. L. Amarasingha ◽  
A. M. B. Priyadarshani
Keyword(s):  
Optimum Ph ◽  
Optimum Ph And Temperature

Water activity, temperature, and pH effects on growth of Fusarium moniliforme and Fusarium proliferatum isolates from maize

1995 ◽  
Vol 41 (12) ◽  
pp. 1063-1070 ◽  
Author(s):  
Sonia Marin ◽  
Vicente Sanchis ◽  
Naresh Magan
Keyword(s):  
Water Activity ◽  
Fusarium Moniliforme ◽  
Potential Temperature ◽  
Fusarium Proliferatum ◽  
Ph Effects ◽  
Optimum Ph ◽  
Effects Of Ph ◽  
Activity Temperature ◽  
Optimum Ph And Temperature

The effects of water activity (aw, 0.994–0.90 ≡ 0.4–14.0 (–)MPa water potential), temperature (4–45 °C), and pH (3.6, 5.5, 7.0), and their interactions on growth of isolates of Fusarium moniliforme and Fusarium proliferatum were determined in vitro on a maize extract agar medium. Growth of two isolates of F. moniliforme and four isolates of F. proliferatum were significantly influenced by water activity regardless of solute type used (NaCl, glycerol, or glucose). However, at steady-state aw levels, growth was optimum at 0.994–0.98 aw and reduced significantly at 0.92 aw. Further detailed studies with one isolate of F. moniliforme (25N) and two isolates of F. proliferatum (73N, 13 IN) showed that growth occurred over the range of 0.994–0.90 aw in the temperature range 20–35 °C with slight differences between species. Growth did occur at 4 °C and 0.994–0.96 aw, but no growth was recorded at 40 and 45 °C regardless of aw. Profiles of aw × temperature relations for growth of these two species were constructed from these data for the first time. Optimum pH and temperature for growth was 5.5 and 25 °C for both isolates of F. proliferatum, and pH 7.0 and 30 °C for the isolate of F. moniliforme. However, for the latter isolate at <0.98 aw, optimum pH and temperature for growth changed. The effects of pH, temperature, and aw for single, two-way and three-way interactions were all found to be statistically significant for these three isolates. The ecological significance of this information for understanding these important fumonisin-producing fungi is discussed.Key words: water activity, temperature, fumonisin-producing, Fusarium moniliforme, Fusarium proliferatum, maize.

Trans-sialidase Associated with Atherosclerosis: Defining the Identity of a Key Enzyme Involved in the Pathology

2019 ◽  
Vol 20 (9) ◽  
pp. 938-941
Author(s):  
Victor Y. Glanz ◽  
Veronika A. Myasoedova ◽  
Andrey V. Grechko ◽  
Alexander N. Orekhov
Keyword(s):  
Acid Metabolism ◽  
Research Subject ◽  
Disease Pathogenesis ◽  
Sialidase Activity ◽  
Ph Values ◽  
Ldl Particles ◽  
Optimum Ph ◽  
Key Enzyme ◽  
St6gal I

Atherosclerosis is associated with the increased trans-sialidase activity, which can be detected in the blood plasma of atherosclerosis patients. The likely involvement in the disease pathogenesis made this activity an interesting research subject and the enzyme that may perform such activity was isolated and characterized in terms of substrate specificity and enzymatic properties. It was found that the enzyme has distinct optimum pH values, and its activity was enhanced by the presence of Ca2+ ions. Most importantly, the enzyme was able to cause atherogenic modification of lowdensity lipoprotein (LDL) particles in vitro. However, the identity of the discovered enzyme remained to be defined. Currently, sialyltransferases, mainly ST6Gal I, are regarded as major contributors to sialic acid metabolism in human blood. In this mini-review, we discuss the possibility that atherosclerosis- associated trans-sialidase does, in fact, belong to the sialyltransferases family.

scholarly journals A Novel In Vitro Model for Determining the Optimum pH and Dose Volume of New Liquid Alginate for Infant Reflux Suppression

Drugs in R&D ◽  
2021 ◽  
Author(s):  
Jeanine Fisher ◽  
Fiona McLaughlin ◽  
Neil Fawkes ◽  
Hannah Tipple ◽  
Cathal Coyle ◽  
...  
Keyword(s):  
In Vitro Model ◽  
Dose Volume ◽  
Optimum Ph ◽  
Vitro Model

scholarly journals Biochemical and Functional Characterization of Anthocyanidin Reductase (ANR) from Mangifera indica L.

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2876 ◽  
Author(s):  
Lin Tan ◽  
Mei Wang ◽  
Youfa Kang ◽  
Farrukh Azeem ◽  
Zhaoxi Zhou ◽  
...  
Keyword(s):  
Enzyme Assay ◽  
Molecular Mechanisms ◽  
Mangifera Indica ◽  
Functional Characterization ◽  
Citrate Buffer ◽  
Anthocyanidin Reductase ◽  
High Amino Acid ◽  
Optimum Ph

Mango (Mangifera indica L.) is abundant in proanthocyanidins (PAs) that are important for human health and plant response to abiotic stresses. However, the molecular mechanisms involved in PA biosynthesis still need to be elucidated. Anthocyanidin reductase (ANR) catalyzes a key step in PA biosynthesis. In this study, three ANR cDNAs (MiANR1-1,1-2,1-3) were isolated from mango, and expressed in Escherichia coli. In vitro enzyme assay showed MiANR proteins convert cyanidin to their corresponding flavan-3-ols, such as (−)-catechin and (−)-epicatechin. Despite high amino acid similarity, the recombinant ANR proteins exhibited differences in enzyme kinetics and cosubstrate preference. MiANR1-2 and MiANR1-3 have the same optimum pH of 4.0 in citrate buffer, while the optimum pH for MiANR1-1 is pH 3.0 in phosphate buffer. MiANR1-1 does not use either NADPH or NADH as co-substrate while MiANR1-2/1-3 use only NADPH as co-substrate. MiANR1-2 has the highest Km and Vmax for cyanidin, followed by MiANR1-3 and MiANR1-1. The overexpression of MiANRs in ban mutant reconstructed the biosynthetic pathway of PAs in the seed coat. These data demonstrate MiANRs can form the ANR pathway, leading to the formation of two types of isomeric flavan-3-ols and PAs in mango.

Seasonal activity of uridine 5'-diphosphoglucose:coniferyl alcohol glucosyltransferase in relation to cambial growth and dormancy in conifers

1998 ◽  
Vol 76 (3) ◽  
pp. 486-493 ◽  
Author(s):  
R A Savidge ◽  
H Förster
Keyword(s):  
Gene Expression ◽  
Seasonal Variation ◽  
Pinus Banksiana ◽  
Coniferyl Alcohol ◽  
Seasonal Activity ◽  
Cambial Growth ◽  
Optimum Ph ◽  
Lateral Meristem ◽  
Cambial Zone

Uridine 5'-diphosphoglucose:coniferyl alcohol glucosyltransferase (CAGT), the enzyme catalyzing synthesis of coniferin from coniferyl alcohol and uridine 5'-diphosphoglucose, was investigated throughout an annual cycle of cambial growth and dormancy in Pinus banksiana Lamb. During dormancy, CAGT activity was not detected in the cambium. CAGT became weakly active in springtime when fusiform cells of the lateral meristem changed from densely protoplasmic to highly vacuolated states, just prior to resumption of cell-division activity. During cambial growth and xylogenesis, CAGT activity in cambial derivatives was greater than that found in the cambial zone. In both cambial zone and developing xylem, seasonally changing CAGT activity paralleled seasonal variation in endogenous coniferin content. CAGT activity disappeared when the cambium entered dormancy in August, prior to completion of lignification in the last differentiating latewood tracheids. In vitro, exogenous coniferin at 0.1 mmol ·L-1 promoted CAGT activity (optimum pH 7.8, temperature 40°C); however, coniferin at >10 mmol ·L-1 inhibited CAGT activity, in agreement with endogenous coniferin content of developing xylem not exceeding that level. The results indicate that the promoter controlling CAGT gene expression may be cambial specific and linked to the overall control of seasonal cambial growth and dormancy.Key words: cambium, coniferin, lignin, phenology, Pinus banksiana, xylogenesis.

scholarly journals Immobilization of alpha-amylase produced by Bacillus circulans GRS 313

2003 ◽  
Vol 46 (2) ◽  
pp. 167-176 ◽  
Author(s):  
Gargi Dey ◽  
Singh Bhupinder ◽  
Rintu Banerjee
Keyword(s):  
Calcium Alginate ◽  
Immobilized Enzyme ◽  
Fold Increase ◽  
Alginate Beads ◽  
Hydrolysis Kinetics ◽  
Initial Activity ◽  
Reaction Conditions ◽  
Bead Size ◽  
Optimum Ph ◽  
Optimum Ph And Temperature

A maltooligosaccharide-forming amylase from B circulans GRS 313 was immobilized by entrapment in calcium alginate beads. The immobilized activity was affected by the size of the bead and bead size of 2mm was found to be most effective for hydrolysis. Kinetics constants, Km and Vmax were estimated and were found to be affected by the bead size. The catalytic activity of the enzyme was studied in presence of various starchy residues and metal ions. HgCl2, CuSO4 and FeCl3 caused inhibition of the enzyme. The reaction conditions, pH and temperature, was optimized using response surface methodology. At the optimum pH and temperature of 4.9 and 57ºC, the apparent activity was 25.6U/g of beads, resulting in almost 2-fold increase in activity. The immobilized enzyme showed a high operational stability by retaining almost 85% of the initial activity after seventh use.

scholarly journals The Effect of pH Stress on the Survival of Rhizobium Trifolii and Sinorhizobium Meliloti in Vitro

2013 ◽  
Vol 70 (2) ◽  
pp. 449-450
Author(s):  
Monica NISTE ◽  
Roxana VIDICAN ◽  
Ioan ROTAR ◽  
Rodica POP
Keyword(s):  
Sinorhizobium Meliloti ◽  
Agar Medium ◽  
Rhizobium Trifolii ◽  
Ph Values ◽  
Optimum Ph ◽  
Yeast Extract Mannitol ◽  
Rhizobial Species ◽  
The Impact ◽  
Different Soils

Nitrogen-fixing symbiotic bacteria known as rhizobia can exist in different soils and adapt to different environmental conditions. The aim of this study was to determine the impact of pH on the growth of Rhizobium trifolii and Sinorhizobium meliloti. Rhizobial species were isolated using yeast extract mannitol agar medium) in which the pH values were adjusted to 5.0, 6.0, 8.0 and 9.0 by adding HCl and NaOH. The optimum pH for rhizobia is neutral or slightly alkaline (pH 8) and they are more sensitive to acidity. Sinorhizobium meliloti developed better in an acid medium compared to Rhizobium trifolii.

scholarly journals Differences in the autocatalytic cleavage of pro-PC2 and pro-PC3 can be attributed to sequences within the propeptide and Asp310 of pro-PC2

1998 ◽  
Vol 334 (3) ◽  
pp. 531-537 ◽  
Author(s):  
Kathleen SCOUGALL ◽  
Neil A. TAYLOR ◽  
Joanne L. JERMANY ◽  
Kevin DOCHERTY ◽  
Kathleen I. J. SHENNAN
Keyword(s):  
Secretory Pathway ◽  
Cell Types ◽  
Structural Features ◽  
Neuroendocrine Cells ◽  
Acidic Ph ◽  
Ph Optimum ◽  
Equivalent Position ◽  
Optimum Ph ◽  
Pro Region

PC2 and PC3 are subtilisin-like proteases involved in the maturation of prohormones and proneuropeptides within neuroendocrine cells. They are synthesized as zymogens that undergo autocatalytic maturation within the secretory pathway. Maturation of pro-PC2 is slow (t½ > 8 h), exhibits a pH optimum of 5.5 and is dependent on calcium (K0.5 2 mM), while pro-PC3 maturation is relatively rapid (t½ 15 min), exhibits a neutral pH optimum and is not calcium dependent. These differences in the rates and optimal conditions for activation of the proteases may contribute to the diversity of products generated by these proteases in different cell types. Although highly similar, there are two major differences between pro-PC2 and pro-PC3: the presence of an aspartate at position 310 in pro-PC2 compared with asparagine at the equivalent position in pro-PC3 (and all other members of the subtilisin family), and the N-terminal propeptides, which exhibit low sequence identity (30%). With a view to establishing the structural features that might be responsible for these differences in the maturation of pro-PC2 and pro-PC3, Asp310 in pro-PC2 was mutated to Asn, and Asn309 in pro-PC3 was mutated to Asp. Chimaeric proteins were also made consisting of the pro-region of PC2 fused to the mature portion of PC3 and the pro-region of PC3 fused to the mature region of PC2. The wild-type and mutant DNA constructs were then transcribed and translated in an in vitro system capable of supporting maturation of pro-PC2 and pro-PC3. The results demonstrated that Asp310 of pro-PC2 is responsible for the acidic pH optimum for maturation. Thus changing Asp310 to Asn shifted the pH optimum for maturation to pH 7.0. However, changing Asn309 of pro-PC3 to Asp had no effect on the optimum pH for maturation of pro-PC3. A chimaeric construct containing the propeptide of pro-PC2 attached to PC3 shifted the pH optimum for maturation from pH 7.0 to 6.0 and slowed down the rate of maturation (t½ > 8 h). When attached to PC2, the pro-region of pro-PC3 had no effect on the optimum pH for maturation (pH 5.5–6.0), but it did accelerate the rate of maturation (t½ 2 h). These results demonstrate that Asp310 and the pro-region of pro-PC2 contribute to the acidic pH optimum and low rate of maturation of this zymogen relative to its closely related homologue PC3.

scholarly journals Purification and Characterization of a Feruloyl Esterase from the Intestinal Bacterium Lactobacillus acidophilus

2004 ◽  
Vol 70 (4) ◽  
pp. 2367-2372 ◽  
Author(s):  
Xiaokun Wang ◽  
Xin Geng ◽  
Yukari Egashira ◽  
Hiroo Sanada
Keyword(s):  
Lactobacillus Acidophilus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Hydrophobic Interaction Chromatography ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Feruloyl Esterase ◽  
Intestinal Bacterium ◽  
Optimum Ph ◽  
Optimum Ph And Temperature

ABSTRACT Dietary ferulic acid (FA), a significant antioxidant substance, is currently the subject of extensive research. FA in cereals exists mainly as feruloylated sugar ester. To release FA from food matrices, it is necessary to cleave ester cross-linking by feruloyl esterase (FAE) (hydroxycinnamoyl esterase; EC 3.1.1.73). In the present study, the FAE from a human typical intestinal bacterium, Lactobacillus acidophilus, was isolated, purified, and characterized for the first time. The enzyme was purified in successive steps including hydrophobic interaction chromatography and anion-exchange chromatography. The purified FAE appeared as a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular mass of 36 kDa. It has optimum pH and temperature characteristics (5.6 and 37°C, respectively). The metal ions Cu2+ and Fe3+ (at a concentration of 5 mmol liter−1) inhibited FAE activity by 97.25 and 94.80%, respectively. Under optimum pH and temperature with 5-O-feruloyl-l-arabinofuranose (FAA) as a substrate, the enzyme exhibited a K m of 0.0953 mmol liter−1 and a V max of 86.27 mmol liter−1 min−1 mg−1 of protein. Furthermore, the N-terminal amino acid sequence of the purified FAE was found to be A R V E K P R K V I L V G D G A V G S T. The FAE released FA from O-(5-O-feruloyl-α-l-arabinofuranosyl)-(1→3)-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose (FAXX) and FAA obtained from refined corn bran. Moreover, it released two times more FA from FAXX in the presence of added xylanase.

An in vitro comparison of some biochemical and biological properties of California and Morocco isolates of Spiroplasma citri

1979 ◽  
Vol 25 (10) ◽  
pp. 1125-1132 ◽  
Author(s):  
E. C. K. Igwegbe ◽  
Clauzell Stevens ◽  
John J. Hollis Jr.
Keyword(s):  
Biological Properties ◽  
Tetrazolium Chloride ◽  
Potassium Tellurite ◽  
Spiroplasma Citri ◽  
Antimicrobial Substances ◽  
Solid Media ◽  
Corn Stunt ◽  
Optimum Ph ◽  
Corn Stunt Spiroplasma

California (CI) and Morocco (MI) isolates of Spiroplasma citri incubated at 4, 24, or 32 °C yielded typical mycoplasma colonies on agar at each passage. MI but not CI incubated at 37 °C yielded a few colonies at first passage only, but both isolates did not survive 42 °C for 3 days. In liquid and solid media, best growth of both isolates occurred between pH 7.0 and pH 8.5 and the optimum pH for growth in liquid medium was 7.5 (CI) and 8.5 (MI). The sensitivity of CI or MI to 21 antimicrobial substances was identical in most cases. Corn stunt spiroplasma (CSS) and CI had similar antimicrobial substance spectrum, although CSS was much more sensitive to any given substance than CI. CI fermented the following with acid production: cellobiose, dextrose, galactose, trehalose, fructose, mannitol. maltose, and sucrose. MI fermented all these in addition to arabinose, mannose. sorbitol, and raffinnose. Arginine but not urea was hydrolyzed by both isolates. CI or MI failed to reduce potassium tellurite, methylene blue, or tetrazolium chloride.

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