Acid Ribonuclease Activity Research Articles

PHYSIOLOGICAL AND BIOCHEMICAL CHANGES IN CATHARANTHUS ROSEUS L. IN RESPONSE TO BORON NUTRITION

Catharanthus roseus L., a medicinally important plant was grown till maturity at varying levels of boron (0.033, 0.066, 0.33 and 3.3 mg B L−1) supply. Optimum yield was observed in plants receiving 0.33 mg B L−1. Plants receiving deficient boron showed growth reduction and visual symptoms such as chlorosis and cupping of young emerging leaves and apical tip necrosis. The number and size of the flowers, pods and seeds formed and the pollen viability of the boron deficient plants was markedly reduced. The threshold values for deficiency and toxicity were 57 and 79 μg B g−1 dry weight for vegetative growth and 60.4 and 68.9 μg B g−1 dry weight for reproductive growth, respectively, and is reported for the first time in periwinkle. An increase was observed in reducing and non-reducing sugars and in activity of acid phosphatase and ribonuclease in boron stressed plants.

Study of some Hydrolytic Enzymes in Sera and Saliva of Patients with Oral Epithelial Tumors

The present study was designed to investigate the changes in the activity and specific activity of some hydrolytic enzymes like - amylase, alkaline and acid RNase in sera and saliva of patients with oral epithelial tumors (benign and malignant). Then follow up the variation of these enzymes using polyacrylamide gel electrophoresis technique to evaluate the changes of these isoenzymes due to the presence of the tumors. Thirty three patients with oral tumors (benign and malignant) aged from 15-75 years attending the specialized surgery hospital in Baghdad medical city, were included in the present study. Thirty one healthy individuals of matched age and gender were utilized as control. The results indicated the presence of highly significant increase (P> 0.001)of sera alk. RNase activity (U/L) in both benign and malignant groups in comparison to that of control. The specific activity results (U/mg) showed also a significant increase (P> 0.05) in both benign and malignant groups. The results of acid RNase activity and specific activity reflected a non significant increase in both benign and malignant groups. The salivary amylase activity (U/L) and specific activity (U/mg) showed significant decrease (P> 0.001) in malignant group, whereas the sera amylase activity and specific activity revealed a non significant increase in both benign and malignant groups.

Impact of Boron Deficiency on Changes in Biochemical Attributes, Yield, and Seed Reserves in Chickpea

To determine the effect of boron (B) deficiency on biomass, reproductive yield, metabolism, and alterations in seed reserves of chickpea (Cicer arietinum L.) cv. ‘13.G‐256,’ plants were grown in refined sand until maturity at deficient (0.033 mg L−1) and adequate (0.33 mg L−1) B, supplied as boric acid (H3BO3). Boron‐deficient plants exhibited visible deficiency symptoms in addition to reduced number of pods and seeds, resulting in lowered biomass and economic yield. Boron deficiency lowered the concentration of B in leaves and seeds, photosynthetic pigments (leaves), Hill reaction activity, starch (in leaves and seeds), and proteins and protein N (in seeds), whereas phenols, sugars (in leaves and seeds), and nonprotein N (in seeds) were elevated. Specific activity of peroxidase (POX) increased in leaves and pod wall and decreased in seeds, while activity of acid phosphate and ribonuclease were stimulated in leaves, seeds, and pod wall in B‐deficient chickpea.

Effect of Hemodialysis on Acid Leukocyte-Type Ribonuclease, Alkaline Ribonuclease and Polymorphonuclear Elastase Serum Levels in Patients with End-Stage Renal Disease

Background: Low-molecular-weight proteins (LMWPs) are substances of molecular weights 10–35 kDa, which accumulate in plasma of patients with end-stage renal disease (ESRD) due to the abolishment of plasma renal filtration. LMWPs are considered as a separate group of uremic toxins. Aim: The influence of hemodialysis (HD) on the release of some LMWPs from leukocytes was assessed by comparing levels of serum pancreatic-type alkaline RNase and leukocyte-type acid RNase as well aspolymorphonuclear (PMN) elastase. Methods: The mentioned proteins were assayed in 58 ESRD patients on HD prior and after the dialysis session and compared with the results obtained from 36 healthy subjects. The levels of elastase and acid and alkaline RNase were correlated with HD parameters, residual diuresis, predialysis concentrations of serum creatinine, urea and albumin as well as pre- and postdialysis granulocyte count. Results: Changes in PMN elastase produced by the dialysis session positively correlate with changes in acid RNase levels (r = 0.3650; p = 0.0061), while there is no such correlation for alkaline RNase. There is a negative correlation between pre- and postdialysis differences in levels of acid and alkaline RNases (r = –0.3542; p = 0.008), indicating that HD induces liberation of a factor suppressing alkaline RNase. Levels of acid and alkaline RNase negatively correlate with residual diuresis, indicating its significance in control of LMWP accumulation (r = –0.3970; p = 0.0025; r = –0.2596; p = 0.0533, respectively). Conclusions: Dialysis treatment causes an increase in both acid leukocyte-type and alkaline pancreatic-type RNase activity in plasma. Dialysis-related increases in acid RNase activity correlate with the respective changes in PMN elastase, which suggests that leukocyte activation during dialysis contributes to an increase in plasma LMWPs.

BIOCHEMICAL STUDIES ON ACID AND ALKALINE RIBONUCLEASE IN SERA OF WOMEN WITH DIFFERENT OVARIAN TUMORS

Acid and alkaline ribonuclease (RNase) activities have been assayed in (14) serum samples of women with histological confirmed ovarian carcinoma, (26) samples of women with benign ovarian tumors, and (27) serum samples of healthy women without any clinically detectable diseases. The mean values of acid and alkaline RNase specific activities were statistically increased in the cancer group (p<0.001) in comparison with those of other groups. The ratio of acid to alkaline RNase (Ac/Al) activities was statistically decreased in the cancer group as compared with those of other groups. Serum alkaline RNase levels were estimated in sera of the above mentioned groups using bovine pancreatic RNase (A), as a standard. A markedly increase in this level in sera of the cancer group was observed when matched with those of other groups. Different alkaline RNase forms were detected in sera of control, benign and malignant tumors groups using gel filtration chromatography (1.6  60 cm. Sephadex G75 column). The results indicate the presence of five different forms in each case, which were different in their molecular weights.

Growth hormone modulates the degradative capacity of muscle nucleases but not of cathepsin D in post-weaning mice

We determined whether recombinant human growth hormone (rhGH) administration might modulate the enzyme degradative capacity of the muscle lysosomal system and influence muscle growth. Muscle cathepsin D, acid RNase and DNase II activities are determined in the gastrocnemius muscle of rhGH-treated post-weaning female BALB/c mice. Linear regressions were used to analyze the relationships of each enzyme with their respective substrate. GH induced a depletion-recovery response of muscle growth through a mechanism which is similar to catch-up growth. In these conditions, cathepsin D activity decreased with age in all animals (GH: 40%; saline: 79%), showing a substantial developmental decline that could reflect changes in the rate of protein breakdown. However, the degradative capacity of cathepsin D was paradoxically unmodified in rhGH-mice compared with saline mice (according to the enzyme vs. substrate linear regression slope), in spite of the increase in enzyme activity elicited by GH. This suggests that the muscle protein breakdown is not increased by GH-treatment in post-weaning mice. The enhancement of muscle protein deposition as indicated by the augmented muscle cell size (protein:DNA ratio) of rhGH-mice (increased 178% from 25 to 50 days) vs. saline, can be attributed to a higher muscle K(RNA). In contrast, acid RNase and DNase II activities directly participate in muscle RNA and DNA degradation. Both nucleases were inhibited by GH treatment (a decrease of 48% and 63%, respectively, vs. saline at 50 days). The decrease in RNase activity suggests an inverse relation between the rate of protein synthesis (high) and acid RNase activity (low), leading to spare muscle RNA for synthesizing protein during catch-up growth. Also, low DNase II activity could contribute to inhibiting of muscle DNA degradation, facilitating muscle growth. Thus, GH seems to act as a direct modulator of the degradative capacity of skeletal muscle nucleases but not of cathepsin D, influencing DNA and RNA degradation during the depletion-recovery response to GH of gastrocnemius muscle in female post-weaning mice.

Picrotoxin-induced convulsions and lysosomal function in the rat brain

The effect of picrotoxin-induced convulsions on lysosomal function in rat brain were evaluated by measuring the free as well as total acid phosphatase, cathepsin D, acid ribonuclease (RNAse II) and acid deoxyribonuclease (DNAse II) activities. Following picrotoxin treatment the free RNAse II activity increased whereas the total activities of practically all the other enzymes decreased. Paradoxically, the cathepsin D activity, free as well the total was completely abolished. In case of all the enzymes the ratio of Total activity/Free activity decreased indicating increased lysosomal membrane fragility which could lead to process of neurodegeneration in the epileptic animals.

Phosphorus Stress Alters Boron Metabolism of Mustard

The study has been made to understand the role of phosphorus in changing the boron (B) metabolism of mustard (Brassica campestris L.) cv. T9 by growing the plants in refined sand at deficient (0.3 μM), adequate (30 μM) and excess (300 μM) levels of boron, each at three levels of phosphorus (P), low (0.15 mM), normal (1.5 mM) and excess (3.0 mM). The synergy between B and P was reflected when low phosphorus accentuated the effects of B deficiency by lowering further the reduced dry weight, total seed yield and increased further the concentration of reducing sugars, phosphorylated protein and activities of acid phosphatase and ribonuclease in B deficient leaves. The effects of excess boron in mustard, viz., reduction in dry weight, seed weight, contents of reducing sugars, organic P, oil content, activity of ribonuclease and stimulating leaf boron, content of inorganic P, phosphorylated protein were accelerated further by combined toxicity of both nutrients. No seeds were produced at deficient B even on increasing the P supply to twice that of adequate amount. The synergy was again observed between B and P when low phosphorus accentuated boron excess effects, i.e., the depression in dry weight, seed yield, reducing sugars, organic P, and oil content and increasing further B and activity of ATPase in young leaves in low P–excess B treatment in mustard.

LIPID, CARBOHYDRATE, AND PROTEIN ACCUMULATION IN Mn-TREATED RICE

The accumulation of lipids, carbohydrates, and proteins was investigated in manganese (Mn)-treated rice (Oryza sativa L. cv. Safari). Rice plants were grown over a 15, 21, and 28-day "period in nutrient solutions containing Mn concentrations "varying between 0.125 and 32 mg l−1 . In all the experimental periods rice root and shoot concentrations of Mn increased continuously until the highest Mn treatment. The contents of acyl lipids did not vary significantly with increasing Mn concentrations. The levels of starch increased only after the 2 mg l−1 Mn treatment and from day 21 after germination onwards. In all the experimental periods the concentration of soluble carbohydrates decreased in the shoots after the 2 mg l−1 Mn treatment. In the roots, this tendency was also detected in 21 and 28-days-old plants. In these tissues, the protein content did not vary significantly until 28 days after germination, but in the shoots a decrease was found in 21 and 28-day-old plants, from 0.5 mg l−1 onwards. In both root and shoot tissues, protease activity remained unchanged in 15-day-old plants, but in the following experimental periods an increase was found in the highest Mn treatment. In the shoot, the acid RNAse activity increased in 21 and 28-day-old plants, from 0.5 mg l−1 onwards. The interaction between excess Mn and lipids, carbohydrates, and proteins before and after the end of the mobilization of seed reserves was evaluated.

Effect of Abdominal Surgery on the Activity of Acid and Alkaline Ribonucleases in Rats

Ribonucleases (RNases) are a group of enzymes that hydrolyze different classes of RNA. It has been suggested that RNase activity in cells can act to indirectly regulate protein synthesis by controlling RNA degradation. However, little is known about the role of RNases under conditions characterized by a sudden increase of protein synthesis, such as with surgical trauma. The aim of this study was to investigate the effect of abdominal surgery on acid and alkaline RNase activities in rat liver. Acid and alkaline RNase activities decreased significantly at 3 h after surgery, reaching the lowest level at 16 h (63% less than control) for the acid and 6 h (39% less than control) for the alkaline activities. Acid RNase activity returned to its initial values 20 h after surgery, while alkaline RNase activity remained decreased even 24 h after surgery. In order to determine whether the observed decreases in RNase activity were produced by RNase inhibitors (RIs), the enzymatic activities of both RNases were measured after the addition of zinc, to dissociate possible RI/RNase complexes. Zinc addition increased acid RNase activity by 61%, but had no significant effect on alkaline RNase activity. Administration of cycloheximide (an inhibitor of protein synthesis) 2 h before surgery prevented the decrease of acid RNase activity 12 h after surgery, while there was no effect on the decrease in alkaline RNase activity. These results show that surgery produces a decrease in hepatic acid and alkaline RNase activities. The decreased acid RNase activity could be a consequence of the de novo synthesis of RNase inhibitors as a response to surgical trauma, while the mechanism involved in the decrease of alkaline RNase activity is unclear. Under pathophysiological conditions, which induce a high rate of protein synthesis, such as surgical wounding, decreased acid and alkaline RNase activity could provide an important mechanism for enhanced protein synthesis, by prolonging RNA half-life.

Isolation and characterization of porcine cationic eosinophil granule proteins.

The allergic pig can be used as a large-animal model for studies of allergic reactions in the airways and the role of eosinophils in such reactions. To measure the activation of eosinophils, the release of eosinophil-derived cationic proteins can be used. The purpose of this study was to isolate and characterize cationic proteins derived from porcine eosinophils. Pigs were infested with live Ascaris suum eggs to induce eosinophilia (greater than or = 40% of leukocytes). Blood was collected and leukocytes were prepared by dextran sedimentation. Granules were obtained from the homogenized leukocytes by ultracentrifugation and cationic proteins were extracted and separated by gel filtration, cation exchange and zinc affinity chromatography. Using these methods, three cationic proteins were isolated from pig granulocytes, two of which were shown to originate from the eosinophil. The proteins were characterized according to molecular weight, amino acid composition, N-terminal sequence, isoelectric point, peroxidase and ribonuclease activity and antigenicity. One eosinophil protein was identified as eosinophil peroxidase and the other showed great similarities with human eosinophil cationic protein. The third protein was not specific for eosinophils, and had no obvious equivalent in human granulocytes. The eosinophil-derived proteins may be useful in the studies of eosinophil activation, e.g. in late-phase asthmatic reactions, where the pig represents a new candidate model for large-animal allergy research.

Nuclear—organelle interactions: the immutans variegation mutant of Arabidopsis is plastid autonomous and impaired in carotenoid biosynthesis

The immutans (im) variegation mutant of Arabidopsis thaliana contains green- and white-sectored leaves due to the action of a nuclear recessive gene. The mutation is somatically unstable, and the degree of sectoring is influenced by light and temperature. Whereas the cells in the green sectors contain normal chloroplasts, the cells in the white sectors are heteroplastidic and contain non-pigmented plastids that lack organized lamellar structures, as well as small pigmented plastids and/or rare normal chloroplasts. This indicates that the plastids in im white cells are not affected equally by the nuclear mutation and that the expression of immutans is 'plastid autonomous'. In contrast to other variegation mutants with heteroplastidic cells, the defect in im is not maternally inherited. immutans thus represents a novel type of nuclear gene-induced variegation mutant. It has also been found that the white tissues of immutans accumulate phytoene, a non-colored C40 carotenoid intermediate. This suggests that immutans controls, either directly or indirectly, the activity of phytoene desaturase (PDS), the enzyme that converts phytoene to zeta-carotene in higher plants. However, im is not the structural gene for PDS. A secondary effect of carotenoid deficiency, both in immutans and in wild-type plants treated with a herbicide that blocks carotenoid synthesis, is an increase in acid ribonuclease activity in white tissue. It is concluded that the novel variegation generated by the immutans mutation should offer great insight into the complex circuitry that regulates nuclear-organelle interactions.

Perfusion with picroliv reverses biochemical changes induced in livers of rats toxicated with galactosamine or thioacetamide.

Perfusion of liver of rats toxicated with galactosamine or thioacetamide with a 0.02% solution of picroliv (glycoside fraction of Picrorhiza kurroa) for 30 min (1 ml/min; 6 mg/rat), significantly reversed toxicant-induced changes in the activities of several enzymes. Galactosamine induced increases in the activities of alkaline phosphatase, gamma-glutamyl transpeptidase, acid ribonuclease, acid phosphatase, succinate dehydrogenase and decreases in the activities of Na(+)-K(+)-adenosine triphosphatase (ATPase) and glucose-6-phosphatase (reversed by 40-87%). Similarly, thioacetamide-induced inhibitions of the activities of Na(+)-K(+)-ATPase, Ca(++)-ATPase, Mg(++)-ATPase, succinate dehydrogenase and elevations in the activities of alkaline phosphatase, gamma-glutamyl transpeptidase, and acid ribonuclease were also significantly reversed. A significant reversal of the toxicants-induced decrease in [14C]-leucine incorporation was also observed. These results indicate that picroliv can also reverse D-galactosamine- or thioacetamide-induced hepatic damage in rats.

Copper mediated inhibition on protein synthesis in rice shoots

Abstract Recently several claims of copper (Cu) contamination in the lower reaches of the Sado River in the Alcacer do Sal region of Portugal (a major rice producing area) have been reported. In an attempt to study the effect of excess Cu on protein contents without anthropogenic interventions (amendments with fertilizers and sludges, application of pesticides, etc.), rice (Oryza sativa L.) plants were grown for one month in nutrient solutions containing Cu concentrations ranging from 0.002 to 6.25 mg/L. In order to understand the mechanism responsible for the observed decline of protein content with increasing Cu levels, the membrane permeability as well as the acid RNAse and protease activities were investigated. It was found that the membrane permeability and the acid RNAse activity increased with increasing Cu concentration. An increase in the protease activity was also observed, but only at the two highest Cu treatments. The effects of increasing Cu levels on protein contents are discussed on the basis of the measured acid RNAse and protease activities. The data is also discussed by considering the Cu contamination in the lower reaches of the Sado River.

Picroliv and its components kutkoside and picroside I protect liver against galactosamine-induced damage in rats.

D-Galactosamine (800 mg/kg, intraperitoneally) caused significant decrease in the activities of 5'-nucleotidase, glucose-6-phosphatase and cytochrome P450 and increase in activities of gamma-glutamyl transpeptidase, succinate dehydrogenase, acid phosphatase and acid ribonuclease in liver after 24 hr. The levels of RNA, protein and glycogen decreased while total lipids, phospholipids, cholesterol and lipid peroxides increased. It also increased the serum levels of transaminases, alkaline phosphatase and bilirubin while protein concentration decreased significantly. Oral administration of Picroliv (12 mg/kg/day for 7 days), a standardised iridoid glycoside fraction of Picrorhiza kurroa, significantly prevented the biochemical changes in liver and serum of galactosamine-toxicated rats. Kutkoside (12 mg/kg/day for 7 days) also protected against changes in most of the hepatic and serum constituents studied. Another iridoid glycoside from Picroliv, Picroside I, at the same dose level could only prevent toxicant-induced changes in acid phosphatase, phospholipids and lipid peroxides in liver and alkaline phosphatase in serum. Mixture of Picroside I and Kutkoside in the ratio of 1:1.5 at 12 mg/kg dose elicited lesser response than Picroliv.

A guanyloribonuclease of mouse liver cytosol

The acid RNase activity of mouse liver cytosol has been resolved into two different enzymes named acid RNase I and acid RNase II respectively. Acid RNase I is a typical pancreatic-type enzyme hydrolyzing CpN and UpN bonds. Acid RNase II, however, hydrolyzes GpN bonds in non-hydrogen-bonded regions of the substrate.

Evidence for selection of virulent sub-populations ofEntamorba histolyticaby cholesterol

Quantitatively much higher Concanavalin A (Con. A) agglutinability, haemolytic potency, and activities of acid hydrolases, namely phosphatase (EC 3.1.3.2), ribonuclease (EC 2.7.7.16), deoxyribonuclease (EC 3.1.4.5) and proteinase--were observed in a virulent strain of Entamoeba histolytica (IP-106), as compared to attenuated and avirulent strains (200-NIH) and DKB respectively. In addition, significant differences in these parameters were observed among clonal cultures derived from the latter two cultures by cultivation of single amoebic cells picked out by micromanipulation. Repeated sub-culturing of parent cultures of both these strains in cholesterol-enriched medium resulted in marked enhancement of all the above activities, but no such change occurred in the derived clonal cultures following similar cholesterol treatment. The implication of these findings in relation to enhancement of the virulence of E. histolytica by cholesterol is discussed.

Activities of serum acid ribonuclease in patients with malignant neoplasms or with renal failure

The activities of serum acid ribonuclease (RNase) were determined in patients with malignant neoplasm or with renal failure. The levels were markedly increased in myelogenous leukemia and renal failure, and only slightly increased in solid cancers, lymphoid malignancies and multiple myeloma. These increases correlated significantly with serum LDH activity in myelogenous leukemia and with creatinine levels in other malignancies or renal failure. The acid RNase content of granulocytes was 22.7-fold higher than that of lymphocytes. The increase of serum acid RNase may suggest an increased granulocyte destruction in myelogenous leukemia and a reduced glomerular filtration in other malignant neoplasms and renal failure.

Cytotoxic effects of methylnitrosourea on developing brain.

The effect of methylnitrosourea (MNU) on cerebellar and cerebral DNA, RNA, protein, lysosomal enzymes (acid DNase, RNase, phosphatase, and beta-glucuronidase), and 2',3'-cyclic nucleotide 3'-phosphohydrolase (2',3'-CNPase) activities was studied in rats from birth through 12 days of age. Subcutaneous injection of MNU in a dose of 0.625 mmol/kg caused a suppression of increase in weights and content of DNA, RNA, and protein of cerebellum, but no changes in those of the cerebrum or in body weight. Ratios of protein and RNA to DNA were substantially elevated by MNU in the cerebellum but not in the cerebrum. Acid DNase and acid RNase activities of MNU-treated rats were significantly elevated beyond the increase of these activities in controls in the cerebellum, but no change in these activities by MNU was observed in the cerebrum. A slight elevation in acid phosphatase activity was observed in the cerebellum but not in the cerebrum after MNU pretreatment. Beta-glucuronidase and 2',3'-CNPase activities were not changed in the cerebellum or in the cerebrum. These results suggest that in the developing brain, especially in the cerebellum at the mitotic stage, MNU caused cell damage and inhibited cell mitosis.

In vivo effect of chloramphenicol and thiamphenicol on some enzymes of normal mouse liver

Chloramphenicol a potent inhibitor of bacterial and some mammalian cell protein synthesis, was administered i.p. to a group of mice for 6 consecutive days. Another group of animals was treated similarly with thiamphenicol and a third group served as control. The effects of the two antibiotics on the activity of some liver enzymes; the two pyridoxal 5-phosphate dependent enzymes, kynurenine hydrolase and kynurenine amino-transferase; pyridoxal phosphokinase; β-glucuronidase and acid ribonuclease were determined. Chloramphenicol and thiamphenicol decreased significantly the activities of kynurenine hydrolase, β-glucuronidase and acid ribonuclease and both drugs increased the activity of pyridoxal phosphokinase significantly. Their effect on kynurenine amino-transferase was different, Chloramphenicol decreased while thiamphenicol increased the enzyme activity. Results are discussed and possible explanations suggested.