Two deoxyribonucleases from Novikoff ascites hepatoma cells

1968 ◽  
Vol 46 (9) ◽  
pp. 1121-1129 ◽  
Author(s):  
Peter M. K. Ip ◽  
Shan-Ching Sung

Two DNases have been isolated and separated from Novikoff ascites hepatoma by ammonium sulfate fractionation and have been further purified by chromatography on ion-exchange columns of DEAE types.The partially purified acid DNase is free of any measurable RNase activity, while the partially purified alkaline DNase preparation still exhibits RNase activity.The alkaline DNase requires sulfhydryl compounds for maximum activity, whereas the acid DNase does not. Both DNases require Mg2+ ions for maximum activity. EDTA strongly inhibits the alkaline DNase activity and the inhibition can be reversed by the addition of Mg2+ ions. On the other hand, EDTA activates the acid DNase either in the presence or in the absence of Mg2+.Sarkomycin inhibits the alkaline DNase but does not inhibit the acid DNase. Actinomycin D and heparin inhibit both DNase activities.The products of the alkaline DNase digestion consist of four deoxymononucleotides as well as higher oligonucleotides, all terminating in 5′-phosphate. The alkaline DNase seems to exhibit an endonucleolytic mode of attack in the early stage of hydrolysis with a subsequent exonucleolytic action. However, the possibility of contamination by an unknown exonuclease cannot be ruled out. On the other hand, the products of the acid DNase digestion consist mainly of oligonucleotides with average chain length larger than 8 units all terminating in 3′-phosphate. No mononucleotides can be detected. This suggests that the acid DNase is a typical endonuclease and possesses no detectable exonuclease activity.The acid DNase preferentially attacks linkages of the type dPupGp, whereas the preferential linkage(s) for the alkaline DNase has not been established.

1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein synthesis.


1966 ◽  
Vol 4 (2) ◽  
pp. 135-153 ◽  
Author(s):  
John Markakis

The Organisation of African Unity is now three years old. In view of the nature of both its scope and its goals, it would obviously be premature to attempt an evaluation of this organisation at such an early stage. On the other hand, the O.A.U. has grown precociously since its birth in May 1963, and the time is ripe for a description of its rapidly multiplying organs, and for some preliminary observations of the multifarious activity in which they have been engaged. To state that the O.A.U. is still in the cradle stage of its development is to emphasise the obvious. It is hardly surprising also that it should suffer the pains of growth, which are likely to be rather severe in the case of a scheme so ambitiously conceived. These facts must be kept in mind while reviewing the O.A.U. at its present state of development.


Development ◽  
1975 ◽  
Vol 34 (2) ◽  
pp. 429-434
Author(s):  
C. A. Finn ◽  
J. C. S. Bredl

This investigation follows the development of embryos in the uteri of mice in which the differentiation of the implantation chamber has been retarded by the administration of actinomycin D before implantation. For the first 48 h after the induction of implantation both embryonic and extra-embryonic parts of the blastocyst develop, but after 72 h the embryonic parts cease to grow and die. The giant cells and other extra-embryonic tissues, on the other hand, continue to develop for a much longer period, up to 288 h. It is suggested that the actinomycin D, by delaying the formation of the implantation chamber in the endometrium, interferes with the formation of a proper functional connection between the trophoblast and endometrium with the result that the embryo receives insufficient nutrition for its development.


Development ◽  
1956 ◽  
Vol 4 (4) ◽  
pp. 358-375
Author(s):  
D. R. Newth

The neural crest is an embryonic tissue found only in craniate vertebrates, but important in the embryogenesis of all of them in which it has been studied. It may be assumed to be of great antiquity and, indeed, to have been present in the latest common ancestors of cyclostomes and gnathostomes, its acquisition having been an early and critical step in the evolution of the craniates. It follows that its properties in living cyclostomes have a twofold interest. It is possible that it is here in one or more ways ‘primitive’, and that its study will reveal something of an early stage in the evolution of the vertebrate embryo. On the other hand, the presumptive fate of the crest in cyclostomes may differ from that of the crest in higher vertebrates for another reason. For certain structures in gnathostomes that are of crest origin, in particular elements of the cartilaginous visceral skeleton, are only doubtfully homologous with their cyclostome analogues.


2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Zhanpeng Jiang ◽  
Rui Xu ◽  
Changchun Dong

With the advance of the combinatorial chemistry, a large number of synthetic compounds have surged. However, we have limited knowledge about them. On the other hand, the speed of designing new drugs is very slow. One of the key causes is the unacceptable toxicities of chemicals. If one can correctly identify the toxicity of chemicals, the unsuitable chemicals can be discarded in early stage, thereby accelerating the study of new drugs and reducing the R&D costs. In this study, a new prediction method was built for identification of chemical toxicities, which was based on ontology information of chemicals. By comparing to a previous method, our method is quite effective. We hope that the proposed method may give new insights to study chemical toxicity and other attributes of chemicals.


At an early stage of Maxwell’s researches into the theory of plane ‘triangulated’ frameworks whose bars or ‘pieces’ arc connected together by pin-joints he derived a relation between the number of bars, joints and supports, respectively, that was necessary if the forces throughout, due to imposed loads, were to be found by simple statics (1). Those researches were stimulated by the needs of engineers to determine the general and detailed proportions of the then novel iron frameworks, especially for bridges for the developing railway system. Rigidity or stiffness to imposed loads was implied by Maxwell’s criterion. Violation of the criterion would, on the one hand, result in a mechanism whereby the bars would be capable of motion and, on the other hand, in a framework with excess stiffness. Moreover, the latter would be capable of having unknown forces introduced into its bars by, say, malpractice during construction, that would then be additional to those caused by eventual loading; that is, it could be self-strained.


Antichthon ◽  
1968 ◽  
Vol 2 ◽  
pp. 15-31 ◽  
Author(s):  
G.P. Shipp

The study of verbal nouns in Homer is of considerable importance for the understanding of the development of Greek language and thought and hence of methods of expression in the languages of Western Europe. Verbal nouns function primarily in much the same way as verbs, i.e. they express the same ideas as do verbs, and on the other hand they play similar parts in the structure of the sentence to other nouns. From this second aspect there evolves the tendency to particular reference, the ‘concrete’ use. The two functions of verbal nouns are a commonplace of semantic studies. In English we can say (1) in the building of houses=when one is building houses, (2) he came out of the building, and, in the plural, an important step, these buildings are to be demolished. The suffix -ing would be the nearest equivalent to -σις, capable like it of construction from any verb. The particular interest of nouns in -σις and -τύς in Homer is that the secondary type of use is still very rare, for example these nouns hardly ever occur in the plural, and thus the development of the ‘concrete’ use can be observed at a very early stage. The only functionally similar nouns in Homer, of types still in ‘free’ use, are those in -θμóς and -σἰη, which for reasons of space will be mentioned only incidentally, as their use impinges on that of the two other classes.


Author(s):  
Rajan Kumar ◽  
Rakesh Kumar ◽  
Abhinav Anand ◽  
Neha Sharma ◽  
Navneet Khurana

Objective: Neurodegenerative disorders are group of diseased conditions in which there is loss of neuron cells occur. The main objective of this study to find/search out the phytochemical with the help of prediction of activity spectra of substances (PASSs), those show maximum activity over the selected targets of the Parkinson’s disease (PD).Methods: PASSs is a valuable software which is used in this study, to predict the anti-Parkinson activity of different compounds. Canonical simplified molecular-input line-entry system is used for the prediction of anti-Parkinson activity which is obtained from PubChem website. The predicted activity also compared with marketed compound like levodopa.Results: From the study, it was found that resveratrol was the only compound which has the activity on all the selected targets. On the other hand, stemazole and celastrol were found to have the least active compounds as both have the activity only on a single target.Conclusion: In this research work, we tried to compile the information regarding the PASS predicted anti-Parkinson activity of some important phytoconstituents. We found that resveratrol can be a target for further investigation in the development of drug therapy for PD.


2010 ◽  
Vol 53 (1) ◽  
pp. 47-97
Author(s):  
MARLEIN VAN RAALTE

Abstract This article offers a running commentary on De igne 1–10 (with text and translation). The way in which Theophrastus sets out to ascribe to the simple body of fire characteristics of terrestrial, burning fire, and only gradually dismisses his focus on fire (and its alter ego of heat) as a principle seems to indicate an early stage of his thought. On the other hand, a formal analysis of the text shows that the argument bears an unmistakably Theophrastean stamp. Finally it is argued that it cannot be inferred from De igne that Theophrastus adhered to the Aristotelian concept of aithêr, and that it is also very unlikely that he did so. The relevant passages from Theophrastus' botanical treatises and Metaphysics confirm this picture. Even the quite explicit testimonies from Philoponus and Julian seem to allow of an interpretation that does not involve Theophrastus having adopted this Aristotelian concept.


2020 ◽  
Vol 17 (2) ◽  
pp. 171-182
Author(s):  
Peter Bofinger

The paper discusses the monetary policy of the European Central Bank (ECB) under the presidency of Mario Draghi. It first shows the serious mistakes made under his predecessor, Jean-Claude Trichet, during which period the ECB destabilized rather than stabilized. Draghi, on the other hand, embarked on a more expansive course immediately after taking office, thereby securing the existence of the euro in a very threatening situation. In 2014, he then identified the deflationary risks for the eurozone at an early stage and successfully countered them with massive bond purchases. The undesirable developments for the financial system and especially the banks predicted by his critics, who are to be found primarily among German economists, have not materialized.


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