scholarly journals Vitamin A and carotenoids. The enzymic conversion of β-carotene into retinal in hog intestinal mucosa

1969 ◽  
Vol 114 (4) ◽  
pp. 689-694 ◽  
Author(s):  
Noel H. Fidge ◽  
Frank Rees Smith ◽  
DeWitt S. Goodman
Keyword(s):  
Intestinal Mucosa ◽  
Gel Filtration ◽  
Maximal Activity ◽  
Enzyme Preparations ◽  
Optimum Ph ◽  
Tween 40 ◽  
Ph Range ◽  
Optimum Ph Range ◽  
Β Carotene

The conversion of β-carotene into retinal was studied in vitro with enzyme preparations from homogenates of hog intestinal mucosa. The hog mucosal enzyme was purified about 27-fold by precipitation with ammonium sulphate, chromatography on DEAE-Sephadex and gel filtration on Sephadex G-200. The reaction displayed a narrow optimum pH range (approx. 7·8–8·2). The enzyme was stimulated strongly by the addition of thiols, and was inhibited by thiol inhibitors and by the chelating agents αα′-bipyridyl and o-phenanthroline. The reaction required the addition of an appropriate detergent (or bile salt); maximal activity was obtained by addition of an appropriate combination of detergents and lipid (specifically Tween 40, sodium glycocholate and sphingomyelin). The reaction displayed Michaelis kinetics with Km1·3×10−6m and Vmax.1·1nmole of retinal formed/hr. (for 0·7mg. of enzyme protein). The properties of the hog enzyme are similar to those previously reported for a less purified rat enzyme preparation.

scholarly journals Thermostable Alkaline Phytase from Alcaligenes sp. in Improving Bioavailability of Phosphorus in Animal Feed: In Vitro Analysis

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ponnuswamy Vijayaraghavan ◽  
R. Raja Primiya ◽  
Samuel Gnana Prakash Vincent
Keyword(s):  
Inorganic Phosphate ◽  
Animal Feed ◽  
Alkaline Phytase ◽  
Optimum Ph ◽  
Green Pea ◽  
Ph Range ◽  
Vitro Analysis ◽  
Optimum Ph Range ◽  
In Vitro Analysis

A bacterial isolate, Alcaligenes sp. secreting phytase (EC 3.1.3.8), was isolated and characterized. The optimum conditions for the production of phytase included a fermentation period of 96 h, pH 8.0, and the addition of 1% (w/v) maltose and 1% (w/v) beef extract to the culture medium. This enzyme was purified to homogeneity and had an apparent molecular mass of 41 kDa. The optimum pH range and temperature for the activity of phytase were found to be 7.0-8.0 and 60°C, respectively. This enzyme was strongly inhibited by 0.005 M of Mn2+, Mg2+, and Zn2+. In vitro studies revealed that the phytase from Alcaligenes sp. released inorganic phosphate from plant phytates. Phytase released 1930 ± 28, 1740 ± 13, 1050 ± 31, 845 ± 7, 1935 ± 32, and 1655 ± 21 mg inorganic phosphate/kg plant phytates, namely, chick pea, corn, green pea, groundnut, pearl pea, and chick feed, respectively.

scholarly journals Identification and Occurrence of Perfect Stage and Cultural and Morphological Variants of Colletotrichum gloeosporioides from Guava in Puerto Rico

1969 ◽  
Vol 56 (2) ◽  
pp. 171-180
Author(s):  
Lii-Jang Liu
Keyword(s):  
Puerto Rico ◽  
Optimum Temperature ◽  
Temperature Range ◽  
Optimum Ph ◽  
Conidial Stage ◽  
Colletotrichum Spp ◽  
Morphological Variants ◽  
Ph Range ◽  
Optimum Ph Range

Two strains of Colletotrichum spp., one dark and one light, were isolated from diseased fruits of guava in Puerto Rico. The isolates differ in cultural appearance, physiologic characteristics, and size of conidia. The optimum temperature range for mycelial growth of the dark strain lies between 24° and 28° C. The optimum temperature range for the light strain lies between 28° and 32° C. The optimum pH range for both strains lie between 5 and 7. Perithecia were produced when the dark strain was crossed with the light strain, or grown alone in potato dextrose agar at 24° to 28° C. Perithecia obtained from both isolates were typical of Glomerella cingulata. Ascospore isolations consistently resulted in the recovery of typical C. gloeosporioides cultures. Although conidia produced by the dark strain are significantly longer than those of the light strain, their perithecia are indistinguishable. Both strains are identified as C. gloeosporioides, the conidial stage of G. cingulata. The formation of the sexual stage of C. gloeosporioides in vitro in Puerto Rico has not been reported hitherto.

Effects of incubation fluid pH and fibrolytic enzymes on the in vitro fermentation of pure substrates, assessed using the Reading Pressure Technique (RPT)

2002 ◽  
Vol 2002 ◽  
pp. 208-208 ◽  
Author(s):  
D. Colombatto ◽  
F. L. Mould ◽  
M. K. Bhat ◽  
E. Owen
Keyword(s):  
In Vitro Fermentation ◽  
Commercial Enzyme ◽  
Fibrolytic Enzymes ◽  
Optimum Activity ◽  
Ph Values ◽  
Optimum Ph ◽  
Ph Conditions ◽  
Ph Range ◽  
Optimum Ph Range

Modern feeding practices often lead to ruminal conditions being sub-optimal for fibre digestion. It has been speculated that fibrolytic enzymes, which usually show optimum activity at pH values below 6.0, may be of benefit when applied to diets of high producing animals. This study used a commercial enzyme mixture (EM), already identified as effective; to investigate its optimum pH range with respect to activity and its impact on the fermentation profiles of pure substrates, under differing pH conditions.

scholarly journals Complexing of the CD-3 subunit by a monoclonal antibody activates a microtubule-associated protein 2 (MAP-2) serine kinase in Jurkat cells

1989 ◽  
Vol 262 (2) ◽  
pp. 449-456 ◽  
Author(s):  
C Hanekom ◽  
A Nel ◽  
C Gittinger ◽  
A Rheeder ◽  
G Landreth
Keyword(s):  
T Cells ◽  
Time Course ◽  
Gel Filtration ◽  
Maximal Activity ◽  
Jurkat Cells ◽  
Serine Kinase ◽  
Transient Activation ◽  
Normal Human ◽  
Dose Dependent

Treatment of Jurkat T-cells with anti-CD-3 monoclonal antibodies resulted in the rapid and transient activation of a serine kinase which utilized the microtubule-associated protein, MAP-2, as a substrate in vitro. The kinase was also activated on treatment of Jurkat cells with phytohaemagglutinin, but with a different time course. The activation of the MAP-2 kinase by anti-CD-3 antibodies was dose-dependent, with maximal activity observed at concentrations of greater than 500 ng/ml. Normal human E-rosette-positive T-cells also exhibited induction of MAP-2 kinase activity during anti-CD-3 treatment. The enzyme was optimally active in the presence of 2 mM-Mn2+; lower levels of activity were observed with Mg2+, even at concentrations up to 20 mM. The kinase was partially purified by passage over DE-52 Sephacel with the activity eluting as a single peak at 0.25 M-NaCl. The molecular mass was estimated to be 45 kDa by gel filtration. The activation of the MAP-2 kinase was probably due to phosphorylation of this enzyme as treatment with alkaline phosphatase diminished its activity. These data demonstrate that the stimulation of T-cells through the CD-3 complex results in the activation of a novel serine kinase which may be critically involved in signal transduction in these cells.

scholarly journals Haem disorder in modified myoglobins. Effect of reconstitution procedures

1983 ◽  
Vol 215 (1) ◽  
pp. 117-122 ◽  
Author(s):  
M B Ahmad ◽  
J R Kincaid
Keyword(s):  
Selective Oxidation ◽  
High Spin ◽  
Chromatographic Purification ◽  
Optimum Ph ◽  
Ph Range ◽  
Optimum Ph Range

Apomyoglobin was reconstituted with deuterohaem derivatives under various conditions. The fraction of disordered component, which is characterized by a 180 degree rotation of the haem group, for the various preparations was determined by n.m.r. spectroscopy. By using the procedures described, it was shown that the fraction of disordered component is minimized if the reconstitution is carried out with high-spin ferric haem derivatives within an experimentally determined optimum pH range of 8-9.5. Use of low-spin derivatives in either the ferrous or ferric forms leads to substantial increases in the fraction of disordered form. Attempted removal of the disordered form by selective oxidation and chromatographic purification was not effective.

CHARACTERISTICS OF FOUR RHIZOBIOPHAGES ACTIVE AGAINST RHIZOBIUM MELILOTI

1957 ◽  
Vol 3 (4) ◽  
pp. 651-668 ◽  
Author(s):  
D. T. Parker ◽  
O. N. Allen
Keyword(s):  
Rhizobium Meliloti ◽  
The Other ◽  
Cross Reactions ◽  
Thermal Death ◽  
Optimum Ph ◽  
Ph Range ◽  
Optimum Ph Range ◽  
Standard Techniques

Four phage isolates for strains of Rhizobium meliloti were obtained from sewage and held soil and purified by standard techniques. Plaque sizes ranged from 1.0 to 4.0 mm. The titers of these phages remained unchanged after 24 months' storage at 0° and 4 °C. None of the phages lysed all of the 38 strains of R. meliloti tested, although 29 of these strains were lysed by one of the phages. Of 292 other strains of rhizobia isolated from 108 species of 50 leguminous genera, one of the phages lysed six strains, another, five strains, while the other two phages did not lyse any. None of the phages lysed any of the 40 strains of Agrobaderium and Chromobaderium species tested. Inactivation rates of the four phages by their homologous antisera were linear up to 90% inactivation. Cross-reactions with heterologous antisera showed weak serological relationships between some of the phages. The latent periods of growth ranged from 80 to 90 minutes to 170–180 minutes. Burst sizes of rhizobia infected by the four phages ranged from 80 to 317 particles per bacterium after an adsorption period of 60 minutes at 30 °C. The optimum pH range was 6.4–7.8. Thermal death points in broth were 51 °C, 53 °C, 61 °C, and 70 °C, respectively, for the four phages.

scholarly journals The subcellular distribution of triphosphoinositide phosphomonoesterase in guinea-pig brain

1972 ◽  
Vol 128 (3) ◽  
pp. 579-586 ◽  
Author(s):  
A. Sheltawy ◽  
M. Brammer ◽  
D. Borrill
Keyword(s):  
Guinea Pig ◽  
Subcellular Fractions ◽  
Assay System ◽  
Acid Phosphatases ◽  
Alkaline Phosphatases ◽  
Pig Brain ◽  
Optimum Ph ◽  
Ph Range ◽  
Guinea Pig Brain ◽  
Optimum Ph Range

1. Some properties of the triphosphoinositide phosphomonoesterase from the homogenates of guinea-pig brain were studied. The enzyme has an optimum pH range 6.7–7.3, is stimulated with KCl at a concentration of 0.1m, and under these conditions has Km1.43×10-4m. 2. A factor from the ‘pH5 supernatant’ of guinea-pig brain stimulates the enzyme activity over and above the stimulation produced by KCl. Subcellular fractions of guinea-pig brain varied in their response to the ‘pH5 supernatant’. Maximum stimulation was observed with the P1 fraction, containing myelin and nuclei. 3. An assay system for the enzyme was developed that contained optimum concentrations of both KCl and the ‘pH5 supernatant’. Acid phosphatases were inhibited by NaF, but, in contrast with previous work, no EDTA was added to the assay system to inhibit the alkaline phosphatases. This reagent inhibited the triphosphoinositide phosphomonoesterase. It was estimated that the remaining fraction of non-specific phosphatases can account for only 14% of the observed triphosphoinositide phosphomonoesterase activity. 4. Subcellular fractions of guinea-pig brain were characterized by electron microscopy and subcellular markers. The triphosphoinositide phosphomonoesterase exhibited a distribution between the fractions similar to that of 5′-nucleotidase, but different from that of alkaline phosphatase.

scholarly journals Production of Pectinolytic Enzymes by the Yeast Wickerhanomyces anomalus Isolated from Citrus Fruits Peels

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
María A. Martos ◽  
Emilce R. Zubreski ◽  
Oscar A. Garro ◽  
Roque A. Hours
Keyword(s):  
Single Cells ◽  
Maximal Activity ◽  
Future Application ◽  
Citrus Fruits ◽  
Enzymatic Extract ◽  
Regional Interest ◽  
Pectinolytic Enzymes ◽  
Optimum Ph ◽  
Lyase Activity ◽  
Ph Range

Wickerhamomyces anomalus is pectinolytic yeast isolated from citrus fruits peels in the province of Misiones, Argentine. In the present work, enzymes produced by this yeast strain were characterized, and polygalacturonase physicochemical properties were determined in order to evaluate the application of the supernatant in the maceration of potato tissues. W. anomalus was able to produce PG in liquid medium containing glucose and citrus pectin, whose mode of action was mainly of endo type. The supernatant did not exhibit esterase or lyase activity. No others enzymes, capable of hydrolyzing cell wall polymers, such as cellulases and xylanases, were detected. PG showed maximal activity at pH 4.5 and at temperature range between 40°C and 50°C. It was stable in the pH range from 3.0 to 6.0 and up to 50°C at optimum pH. The enzymatic extract macerated potato tissues efficiently. Volume of single cells increased with the agitation speed. The results observed make the enzymatic extract produced by W. anomalus appropriate for future application in food industry, mainly for the production of fruit nectars or mashed of vegetables such as potato or cassava, of regional interest in the province of Misiones, Argentine.

Biosynthesis of 9-cis-Retinoic Acid from 9-cis-β-Carotene in Human Intestinal Mucosa in Vitro

1994 ◽  
Vol 313 (1) ◽  
pp. 150-155 ◽  
Author(s):  
X.D. Wang ◽  
N.I. Krinsky ◽  
P.N. Benotti ◽  
R.M. Russell
Keyword(s):  
Retinoic Acid ◽  
Intestinal Mucosa ◽  
Β Carotene

Coagulation/flocculation of dye-containing solutions using polyaluminium chloride and alum

2009 ◽  
Vol 59 (7) ◽  
pp. 1343-1351 ◽  
Author(s):  
M. Hasani Zonoozi ◽  
M. R. Alavi Moghaddam ◽  
M. Arami
Keyword(s):  
Dye Removal ◽  
Coagulant Dosage ◽  
Optimum Ph ◽  
Ph Range ◽  
Influence Of Ph ◽  
Acid Blue ◽  
Ph Variations ◽  
Optimum Ph Range ◽  
Low Dosage ◽  
Polyaluminium Chloride

This study aims to compare the performance of Polyaluminium Chloride (PAC) and alum as coagulants to remove a specific type of dye (Acid Blue 292 (AB292)) from dye-containing solution. For this purpose, the influence of pH, coagulant dosage, coagulant aids (kaolinite and bentonite), and initial dye concentration on dye removal efficiency were examined. According to the results, removal of AB292 was absolutely dependent on the pH variations. The maximum dye removal occurred when pH was 7 and 5 for PAC and alum, respectively. Both coagulants efficiently removed the dye (about 85%) with a relatively low dosage (40 mg/l) in their optimum pH range. By adding kaolinite as a coagulant aid, the removal efficiencies tended to increase, especially for lower dosages of PAC and alum. With the increase of initial dye concentration, PAC and alum represented different behaviors. In the case of PAC, Q (the amount of the removed dye per unit mass of coagulant) increased at first and reached to a maximum value, 2.1 mg dye/mg PAC, and then decreased rapidly. While for alum, Q steadily increased with the increase of dye concentration and reached to 2.8 mg dye/mg alum. No reduction of Q occurred for alum with the increase of dye concentration in the range of 25–250 mg/l.

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