Acid Nuclease Activity Research Articles

Effect of Zn2+ Ions on Acid Nuclease Activity in Freshwater Mollusks

Effect of Zn2+ Ions on Acid Nuclease Activity in Freshwater Mollusks

DNase IIβ Distribution and Activity in the Mouse Lens

To map the cellular and subcellular distribution of DNase IIbeta activity in the mouse lens. DNase IIbeta-specific activity was determined by assaying lens lysates prepared from wild-type or DNase IIbeta-null mice. Regional nuclease activity was determined by microdissection of lens samples or a tissue-imprinting assay. Subcellular distribution was determined by density-gradient ultracentrifugation. DNase IIbeta transcripts increased 200-fold in abundance during fiber cell formation, and DNase IIbeta activity accounted for approximately 50% of the acid nuclease activity in the cortical fiber cells. Examination of lenses from DNase IIbeta-null mice confirmed that the enzyme was required for denucleation. In wild-type lenses, nuclei were TUNEL positive before denucleation, indicating that 3'-OH DNA ends had accumulated. However, DNase IIbeta-mediated scission generates 3'-PO(4)(-) DNA ends only. This paradoxical finding was explained by the presence of phosphatases that converted the 3'-PO(4)(-) ends produced by DNase IIbeta into 3'-OH ends. DNase IIbeta activity was strongest early in differentiation, where it was associated with the lysosomal fraction. Later, an increasing proportion of DNase IIbeta activity was found in the cytosol. DNase IIbeta activity correlated with and was necessary for fiber denucleation and was most likely contained initially within fiber cell lysosomes before release into the cytoplasm.

Application of different test systems and biochemical indicators for environmental monitoring of the Troitsa Bay, Sea of Japan

The DNase express test system and the SF-bioassay (sea urchin sperm fertilization bioassay) were used to assess the quality of sea and bottom sediment water sampled at 8 stations of the Troitsa Bay (Possyet Bay, Sea of Japan). The specific activities of 8 enzymes (alkaline and acid DNases, RNases, phosphatases and phosphodiesterases) were determined for the liver and gill tissues of the mussel Crenomytilus grayanus sampled at the same stations. The activities of all enzymes were higher in the liver than in the gills, and the activity of acid nucleases in both tissues was significantly higher than that of alkaline nucleases. The specific activities of some nucleases in the mussel tissues correlated to the level of seawater pollution. The activities of acid RNases and phosphodiesterases decreased in both tissues upon an increase in water pollution, up to 1.5–3 times in the gills, while the activities of alkaline and acid phosphatases and phosphodiesterases increased 1.5–4 times. Thus, the specific activities of acid RNases, phosphatases and phosphodiesterases from mussel liver can be a useful indicator of marine pollution. This approach can be used for biotesting of ocean water and for assessment of the biological condition of invertebrates adapting to various ecological and anthropogenic effects.

Application of rice (Oryza sativa L.) suspension culture in studying senescence in vitro (I). Single strand preferring nuclease activity

Single Strand-Preferring Nucleases (SSPNs) have been implicated in the triggering and progress of cell death pathways, including senescence in higher plants, though the biological roles of such enzymes are still obscure. In the present study, heterotrophic cell suspension cultures of Oryza sativa L. (rice) cv Taipei 309 were used to investigate changes in Single Strand-Preferring Nuclease activity associated with cell death in vitro . An acid nuclease activity (pH 5.5) was found which was strongly stimulated in the presence of 10 mM Zn 2+ and inhibited by 10 mM EDTA and EGTA. An increase in SSPN activity was concomitant with a loss of cell viability, total protein and the onset of stationary phase of growth in the cell cultures. Using DNA-SDS-PAGE two major SSPNs were detected with the molecular weights of 26 KDa and 53.5 KDa. There are possibilities that these two enzymes represent monomeric and dimeric forms of the same nuclease or they are two different enzymes. The 26 KDa nuclease was partially purified using heparin-Sepharose column chromatography. The results confirm the value of plant cell suspension cultures for the investigation of the molecular process underlying plant cell ageing, senescence processes and programmed cell death (PCD). Possible senescence-associated roles of SSPNs are discussed.

Acid nucleases in PSTV-infected tomato ( Lycopersicum esculentum L.) I. Levels of Acid Nuclease Activity in Healthy and PSTV-Infected Tomato Leaves and Callus Tissues

Summary Nuclease activities at pH 5.2 were investigated in potato spindle tuber viroid (PSTV)-infected tomato leaves and calluses. DNase activity per g fresh mass and per mg soluble protein was, approximately, two times higher in infected leaves at «early» stage of pathogenesis than in healthy controls. The activity remained enhanced also when symptoms related to PSTV infection expressed to a greater degree. The nuclease activity was higher with heat denatured ssDNA than with native dsDNA. The ratio of activities did not change significantly upon viroid infection. The activity with RNA in healthy leaves was about forty-fold higher than with dsDNA, but was enhanced only by 19% in infected leaves at the «early» stage of pathogenesis. The nuclease activity with dsDNA was several times higher in tomato calluses than in tomato leaves. Examination of the DNase activities in healthy and PSTV-infected calluses grown at different temperatures showed significant differences and their relation to PSTV pathogenesis.

Morphological alterations and focal deficiency of the histochemical activity of acid and alkaline nucleases in rat liver after chronic administration of phenobarbital

Chronic oral administration of phenobarbital (up to 16 months) did not produce any neoplastic foci or nodules in the liver of male Wistar rats. Decrease of glycogen content and cytoplasmic alterations probably indicating S.E.R. hypertrophy were observed in the hepatocytes localized predominantly in the centrilobular areas of rats after chronic phenobarbital treatment. This treatment induced small foci of alkaline DNAse and RNAse deficient liver cells in the initial stages of the experiment. Acid DNAse and RNAse deficient zones increased in liver parenchyma since the third month of chronic administration of phenobarbital. At later stages of the experiment (7 to 16 months) they concerned in some cases more than 50% of liver parenchyma. The hyperbasophilia and the intensity of methylgreen-pyronin staining which, most probably, indicated the accumulation of nucleic acids also increased progressively with phenobarbital administration in similarly distributed irregular zones. These zones had predominant centrilobular localization. It was suggested that such zonal deficiency of acid nuclease activity might be involved in tumor-promoting action of phenobarbital when separately administered in rats after hepatocarcinogen treatment.

Effect of hydrocortisone on acid nuclease activity in the eye tissues

Effect of hydrocortisone on acid nuclease activity in the eye tissues

A histochemical study of alkaline and acid nuclease activity in the human brain compared to the incidence of malignant tumours

Alkaline and acid DNase and RNase activities were investigated histochemically in human brain. Intense activity of alkaline nucleases was found mainly in the choroid plexus and ependymal epithelium as well as in the leptomeninges. Acid nuclease activity was strongest in all nerve cells. The glial cells demonstrated very weak activity of both acid and alkaline nucleases. Comparison of these results with the incidence of human brain malignant tumours has indicated that low nuclease activity in normal brain cells coincides with the high incidence of malignant tumours deriving from these cells and vice versa. These observations and the results of similar investigations in the rat CNS and in the digestive tube of the rat and man suggest that low nuclease activity in normal cells could be considered to be a factor which may predispose to malignant trans-formation.

A CYTOCHEMICAL STUDY OF ACID PHOSPHATASE AND NUCLEASE ACTIVITY IN THE PLASTID OF CLOSTERIUM ACEROSUM(1).

Acid phosphatase activity in Closterium acerosum has been studied using the Gomori and the azo dye procedures. A modification of the Gomori method was used for detecting the distribution of acid nucleases. The plastid is the major site of acid phosphatase activity luhich may be primarily within pyrenoids, between pyrenoids, or throughout the plastid. The Gomori procedure showed activity within the pyrenoids or in the central core of the plastid, whereas the azo dye method showed activity throughout with an occasional tendency to be localized near the ends. No other cytoplasmic activity was ob-served but evidence for occasional activity in the nucleus is presented. Alkaline phosphatase could not be detected. Acid nuclease activity, which results in the degradation of DNA, RNA, and RNA-Core, has been found in both the nucleus and the plastid. Plastid activity is heat labile, whereas nuclear activity is only slightly diminished after 5 min at 100 C. The results arc interpreted as indicating at least 2 acid phosphatases and 2 nucleases in C. acerosum. The findings are discussed with respect to the distribution of similar enzymes in other organisms.