THE INVERTASE OF THE CORN RADICLE AND ITS ACTIVITY IN SUCCESSIVE STAGES OF GROWTH

1962 ◽  
Vol 40 (1) ◽  
pp. 113-126 ◽  
Author(s):  
J. A. Hellebust ◽  
D. F. Forward

Segments of the first 10 millimeters of corn radicle tips have been analyzed in terms of invertase activity, cell number, fresh and dry weights, and sugar content. Invertase activity per cell increased 40-fold as the meristematic cell advanced to the stage of most rapid elongation, and again subsided as the cell ceased to elongate and entered the stage of maturation. In the growing cell, the concentration of sucrose remained low while that of reducing sugars increased fivefold.The corn radicle invertase was found to be a β-fructofuranosidase with a Km of 0.006 M and a pH optimum of 4.6. Kinetic studies indicate that there is no change in the nature of the corn radicle invertase during cell growth. Equivalent activities of intact cells or segments and homogenates is consistent with the assumption that the enzyme is located outside the permeability barrier of the cells.

Blood ◽  
1977 ◽  
Vol 49 (2) ◽  
pp. 269-280

Kinetic studies in cultures containing 2 X 10(5) peripheral leukocytes from patients with acute myelobastic leukemia revealed extensive, radiation-sensitive increases in thymidine incorporation without parallel increases in cell number. Modest and variable stimulation of 3HTdR incorporation was seen with the addition of either leukocyte- conditioned medium prepared with phytohemagglutin (PHA) or PHA alone. However, using the method of limiting dilution, stimulation was always observed and ranged from 3- to 20-fold in individual patients. By mixing small numbers of intact cells with larger numbers of irradiated autologous cells, quantitative evidence was obtained for a cellular interaction between irradiated, PHA-stimulated populations capable of 3HTdR incorporation. Similar evidence for cell-cell interaction was obtained for normal leukocytes.


Blood ◽  
1977 ◽  
Vol 49 (2) ◽  
pp. 269-280 ◽  

Abstract Kinetic studies in cultures containing 2 X 10(5) peripheral leukocytes from patients with acute myelobastic leukemia revealed extensive, radiation-sensitive increases in thymidine incorporation without parallel increases in cell number. Modest and variable stimulation of 3HTdR incorporation was seen with the addition of either leukocyte- conditioned medium prepared with phytohemagglutin (PHA) or PHA alone. However, using the method of limiting dilution, stimulation was always observed and ranged from 3- to 20-fold in individual patients. By mixing small numbers of intact cells with larger numbers of irradiated autologous cells, quantitative evidence was obtained for a cellular interaction between irradiated, PHA-stimulated populations capable of 3HTdR incorporation. Similar evidence for cell-cell interaction was obtained for normal leukocytes.


2005 ◽  
Vol 27 (2) ◽  
pp. 198-202 ◽  
Author(s):  
Barbara França Dantas ◽  
Luciana de Sá Ribeiro ◽  
Alexandro Pereira da Silva ◽  
Sara Raquel de Souza Luz

The irrigated agriculture at the São Francisco River Valley, Northeast Brazil, shows an increasing production of grapes for winery. Among the wines produced there the one obtained from Vitis vinifera L., cultivar Syrah, stands out due to its adaptation to the climatic conditions of the region. However, little is known about carbohydrates metabolism of vines cultivated in this region. The objective of this work was to evaluate sugar and starch contents and the invertase activity in vines leaves during two consecutive growing seasons. The experiment was carried out at Embrapa Semi-Árido and at Santa Maria Winery, respectively located in Petrolina and Lagoa Grande, Pernambuco-Brazil. Leaves were collected weekly from January to December of 2003 and assessed for reducing sugars, total soluble sugars and starch contents, as well as for acid (AI) and neutral invertases (NI). The results showed that reducing sugars, total soluble sugars and starch contents increased during fruit maturation and are influenced by temperature, radiation and insolation variations. The second growing season showed higher reducing sugars and total soluble sugars content and lower starch content in the leaves than the first one. AI activity was higher than NI activity and these also varied according to weather conditions. During berries ripening, leaves showed higher sugar content and invertase activity, suggesting a higher sugar metabolism and transport during this phase.


1974 ◽  
Vol 32 (02/03) ◽  
pp. 457-464
Author(s):  
Paul C. French ◽  
Jan J. Sixma ◽  
Holm Holmsen

SummaryAdenine uptake into isolated platelet membranes had about the same Km (151 ± 21 • 9 nM) as uptake into intact cells (159 ± 21 nM) and was also competitively inhibited by papaverine and hypoxanthine. No uptake occurred at 0° and accumulated adenine was converted to AMP. AMP was not firmly bound to protein as judged by chromatography of triton X-100 solubilized membranes on Sephadex G25. The pH optimum for adenine uptake was at pH 5-5. Exogenous 5-phosphoribosyl-l-pyrophos- phate strongly stimulated uptake. These data may be explained by uptake of adenine by facilitated diffusion followed by conversion to AMP by adenine phosphoribosyltransferase but group translocation cannot be entirely excluded.


1991 ◽  
Vol 116 (2) ◽  
pp. 239-243 ◽  
Author(s):  
H. L. Sehtiya ◽  
J. P. S. Dendsay ◽  
A. K. Dhawan

SUMMARYAcid and neutral invertase activities in the stem of an early (CoJ 64) and a late cultivar (Col 148) of sugarcane were estimated by incubating stem slices in buffered sucrose solution and measuring the production of reducing sugars. High enzyme activity occurred in young tissue but the activity of both enzymes was considerably lower in the mature internodes. Acid and neutral invertase activity was highest in the midinternode position, corresponding to the region of cell expansion.


2018 ◽  
Vol 14 (3) ◽  
pp. 113-121
Author(s):  
Tamara Torres Tanan ◽  
Marilza Neves do Nascimento ◽  
Romeu da Silva Leite

The Physalisbelongs to the Solanaceae family and has sweetish fruit that can be eaten fresh or processed. In Brazil only Physalis peruvianais commercialized, it is necessary research to encourage the cultivation of other promising speciesof the genus. The aim of this study was evaluate the productivity and the physical and biochemical characteristics of P. angulata, P.pubescensand P. ixocarpafruits, in different stages,in Feira de Santana, Bahia. Productivity and the number of fruits in the breeding period were evaluated.In the fruits, longitudinal (LD) and transverse (TD) diameters, the LD/TD ratio,the masses of fruit, the protein content,reducing sugars,and total soluble sugars were analyzed. The results showed differences between species, with higher number of fruits for P. angulata(140,5). P. ixocarpashowed higher productivity (9 t ha-1) and fruit with greater mass and diameter,however P. pubescensand P. angulatashowed round fruits and higher sugar content, desirable characteristics for fresh consumption and for industrialization.


2011 ◽  
Vol 35 (6) ◽  
pp. 1646-1652 ◽  
Author(s):  
DEVAIAH KAMBIRANDA ◽  
HEMANTH VASANTHAIAH ◽  
SHEIKH M. BASHA

2016 ◽  
Vol 3 (2) ◽  
pp. 295-304
Author(s):  
Fatema Zahan ◽  
Md Masudul Karim ◽  
Tahmina Akter ◽  
Md Alamgir Hossain

Seven potato genotypes that are available in Bangladesh, were grown at the field laboratory under the Crop Botany Department, Bangladesh Agricultural University in 2014. Reducing sugars and free asparagine were determined at freshly harvested potato tubers and those after storing at 80C for 8 months. There was no significant variation of asparagine content in all genotypes of freshly harvested tubers. But a significant difference was found in reducing sugar content. The lowest was in the samples of the genotypes Cardinal and Rumanapakri, and the highest in Hagrai. The variety Diamant appeared to contain the lowest amount of reducing sugars after 8 months storage. The results showed that freshly harvested Cardinal, Rumanapakri and Diamant after storage produced less amount of acrylamide after frying as potato chips or French fries. It may be concluded that screening potato genotypes primarily on their reducing sugar contents could be useful tool to minimize acrylamide formation in potato chips and French fries. Further investigation is needed to find out the factors affecting reducing sugar and asparagine content in potato tubers.Res. Agric., Livest. Fish.3(2): 295-304, August 2016


1985 ◽  
Vol 230 (1) ◽  
pp. 75-82 ◽  
Author(s):  
L D Laury-Kleintop ◽  
I Damjanov ◽  
J A Alhadeff

Mouse tissues contain unusual basic isoelectric forms of α-L-fucosidase (with approximate isoelectric points of 8.3 and 9.0) in addition to the usual acidic and neutral forms previously described in tissues of other species. These unusual forms are very prominent in placenta and foetal tissues and comprise approx, 50-80% of total activity up to 11 days of postnatal development. By 15 days of postnatal development, the basic forms are diminished in amount and comprise not more than 25% of total activity. Neuraminidase treatment of adult mouse liver α-L-fucosidase led to significantly decreased amounts of acidic forms and increased amounts of the basic forms, suggesting that these forms are chemically related at least in part by sialic acid residues. Comparative kinetic studies on mouse liver, human liver and mouse placental α-L-fucosidases indicated that they have the same Km (0.05-0.06 mM) for 4-methylumbelliferyl α-L-fucopyranoside but different pH optima and thermostability properties. Mouse liver α-L-fucosidase has one pH optimum (5.5) and an acidic shoulder (centred around pH 4.0) compared with two distinct optima (4.3 and 6.8) for the human liver enzyme. Mouse placental α-L-fucosidase has a pH-activity curve comparable with that of the mouse liver enzyme except that the acidic shoulder is absent. Mouse liver α-L-fucosidase is considerably more thermolabile after preincubation at 50 degrees C than are the human liver and mouse placental enzymes, which gave similar thermodenaturation curves. Immunochemical studies indicated that mouse and human α-L-fucosidases are dissimilar antigenically but exhibit some cross-reactivity. The IgG fraction of antibody prepared in goat against human liver α-L-fucosidase was ineffective by itself in immunoprecipitating mouse liver α-L-fucosidase, but 63% and 72% of the mouse liver and placental enzymes respectively could be immunoprecipitated in the double-antibody experiments under conditions that immunoprecipitated 92% of the human liver enzyme.


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