Extracellular nuclease produced by a marine bacterium. I. Extracellular deoxyribonuclease formation by a marine Vibrio sp.

1976 ◽  
Vol 22 (10) ◽  
pp. 1437-1442 ◽  
Author(s):  
M. Maeda ◽  
N. Taga

Deoxyribonuclease (DNase) activity was found in the culture fluids of numerous marine bacteria isolated from seawater. Among these organisms, marine bacterium, Vibrio sp., strain No. 2, showed the highest deoxyribonucleic acid – hydrolyzing activity. This organism requires salts of seawater for both growth and extracellular DNase formation. The DNase activity could not be detected in the synthetic seawater culture liquid lacking magnesium ion, and DNase activity decreased in a calcium-deficient medium. The optimum temperature for the growth of this organism was between 15 and 25 °C. The formation of extracellular DNase was the greatest at 20 °C and less activity was found at 10 and 30 °C.

1976 ◽  
Vol 22 (10) ◽  
pp. 1443-1452 ◽  
Author(s):  
M. Maeda ◽  
N. Taga

Extracellular nuclease produced by a marine Vibrio sp., strain No. 2, was purified by salting out with ammonium sulfate and by chromatography on a DEAE-cellulose column and twice on a Sephadex G-200 column. The nuclease was eluted as a single peak in which the deoxyribonuclease (DNase) activity and ribonuclease (RNase) activity appeared together. Polyacrylamide disc gel electrophoresis showed a single band of stained protein which had both DNase and RNase activity. The molecular weight of the enzyme was estimated to be 100 000 daltons. When using partially purified enzyme from the DEAE-cellulose column, the optimum pH for activity was 8.0, and the enzyme was activated strongly by 0.05 M Mg2+ ion and stabilized by 0.01 M Ca2+ ion. These concentrations of Mg2+ and Ca2+ ions are similar to those of the two cations in seawater. Indeed, the enzyme revealed high activity and strong stability when kept in seawater. The presence of particulate matter, such as cellulose powder, chitin powder, Hyflosupercel, Kaolin, and marine mud increased the stability of the enzyme. When the hydrostatic pressure was increased from 1 to 1000 atmospheres, the decrements of the enzyme activity were more pronounced at 30 and 40 °C than at 25 or 50 °C. The enzyme activity was restored after decompression to 1 atm at 30 °C.


1993 ◽  
Vol 38 (5) ◽  
pp. 1091-1097 ◽  
Author(s):  
Margo G. Haygood ◽  
Pamela D. Holt ◽  
Alison Butler

2020 ◽  
Vol 15 (9) ◽  
pp. 1934578X2095328
Author(s):  
Xin Liu ◽  
Tian Deng ◽  
Xueqin Liu ◽  
Xiaohua Lai ◽  
Yanli Feng ◽  
...  

Oligosaccharides have important alimental and medical applications. Dextranase has been used to produce isomalto-oligosaccharides (IMOs). In this study, we isolated dextranase-producing bacteria from sugarcane-cultivated soil. Identification of the isolate based on its phenotypical, physiological, and biochemical characteristics, as well as 16S ribosomal deoxyribonucleic acid gene sequencing yielded Shewanella sp. strain GZ-7. The molecular weight of the dextranase produced by this strain was 100-135 kDa. The optimum temperature and pH for dextranase production were 40 °C and 7.5, respectively. The enzyme was found to be stable at the pH range of 6.0-8.0 and the temperature range of 20 °C-40 °C. Thin-layer chromatography and high-performance liquid chromatography of the enzymolysis products of the substrate confirmed the enzyme to be endodextranase. Under the optimal conditions, the ratio of IMOs could reach 91.8% of the hydrolyzate. The final products were found to efficiently scavenge the 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, and superoxide anion radicals. In general, dextranase and hydrolyzates have high potential prospects for application in the future.


2013 ◽  
Vol 37 (3) ◽  
pp. 575-584 ◽  
Author(s):  
Jiushun Zhou ◽  
Menghao Cai ◽  
Tao Jiang ◽  
Weiqiang Zhou ◽  
Wei Shen ◽  
...  

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