Effect of Ozone on the Activities of Reactive Oxygen Scavenging Enzymes in Rbc of Ozone Exposed Japanese Charr (Salvelinus Leucomaenis)

The effect of ozone exposure on the activities of reactive oxygen scavenging enzymes (SOD†, catalase, GSH-Px) in RBC of Japanese charr (Salvelinus leucomaenis) was examined. Ozone (0, 0.4 and 0.7 ppm as initial concentrations) was exposed to Japanese charr for 30 min, which definitely caused serious membrane damage to RBC of fish. Ozone exposure at 0.4 and 0.7 ppm decreased activities of both catalase and GSH-Px by 80 to 57+ of the control. On the other hand, the activities of SOD remained unaffected even by 0.7 ppm ozone exposure. A hypothesis on the RBC membrane damage and participation of SOD and heme-iron was proposed.     

Polymorphisms detected in actin-related sequences of rats (Rattus norvegicus)

Southern blot hybridization of EcoRI digests of DNAs from 13 rat strains using human cardiac actin gene as a probe revealed polymorphisms in actin-related sequences of rats. EcoRI fragments of 11 kb, 7 kb, 6 kb, 5 kb, 4.5 kb and 4 kb detected in several strains were absent in the remaining strains. The presence of these fragments was suggested to be due to presence of extra sequences homologous to the actin genes, such as processed pseudogenes, in the particular strains. The 13 strains were assigned to each of 7 specific patterns of the polymorphic EcoRI fragments. It was concluded that the polymorphisms of actin-related sequences should be useful for genetic monitoring of laboratory rats.     

Thymidine triphosphate dephosphorylating activity in regenerating rat liver

The enzyme activity of dephosphorylation of thymidine triphosphate was found in microsomal fraction of rat liver. The enzyme activity decreased at the time when [³H]thymidine incorporation into DNA of regenerating liver increased. When the [³H]thymidine incorporation was suppressed by 1,3-diaminopropane, the enzyme activity remained elevated. These results suggest that the enzyme activity appears to be closely linked to DNA synthesis.     

Factors Contributing to the Poor Myelination in the Brain of the Snell Dwarf Mouse

Abstract: Conventional histological examination of the pituitary does not distinguish Snell dwarf mutants (dw/dw) from their normal littermates (+/?) in the neonatal stage. However, immunohistochemical examination of pituitaries of litters born to heterozygous Snell parents revealed that in approximately 25% of the glands examined, the number of positive cells was very low in the neonatal stage. We attempted to delineate the events resulting in the poor myelination in the brain of the Snell dwarf mouse, and to devise an immunohistochemical method for identifying the mutant neonate. Differences in the brain weights of the dw/dw and +/? mice first became apparent on the 10th day of age, and from this time on no further increase in the weight of the dwarf mouse brain was recorded. Increase in CNPase activity was found to be suppressed in the cerebrum and brain stem throughout the developmental stage, but not in the other parts of the brain. The yield of isolated myelin decreased by 58% in the mutant mouse, but CNPase activity was equivalent to that of control myelin. Differences in DNA content per cerebrum from the dw/dw and +/? mice first became apparent on the 10th day of age. Henceforth, the dw/dw mice showed no further increase, although the +/? mice continued to increase. [³H]Thymidine incorporation into the DNA fraction in vivo on the 7th day of age, when glial cell proliferation in the cerebrum is most active, was suppressed to about 50% of the control level in all parts of the dwarf brain. These findings indicate that the poor myelination found in the mutant cerebrum is a hypomyelination due to reduced oligodendroglial proliferation caused by lack of circulating growth hormone.     

Highly Sensitive Assay for Dopamine-β-Hydroxylase Activity in Human Cerebrospinal Fluid by High Performance Liquid Chromatography-Electrochemical Detection: Properties of the Enzyme

Abstract: This paper describes a new, sensitive assay for dopamine-β-hydroxylase (DBH) activity in human cerebrospinal fluid (CSF), serum and brain tissues by high performance liquid chromatography (HPLC) with electrochemical detection (ED). Dopamine (DA) was used as a substrate and was incubated under optimal conditions. Norepinephrine (NE) formed enzymatically from DA was isolated by a double-column procedure, the first column of Dowex-50-H⁺ and the second column of aluminum oxide. NE was adsorbed on the second aluminum oxide column and then eluted with 0.5 M-hydrochloric acid and assayed by HPLC-ED. Epinephrine (EN) was added to each incubation mixture as an internal standard, and this assay was therefore highly reproducible. The peak height in HPLC was linear from 500 fmol to 100 pmol of NE and EN. The lower limit of detection for NE formed enzymatically was about 30 pmol, which indicated that the sensitivity of this procedure was comparable to that of radioassay procedures. We applied the method to measurement of the activity of and examination of some of the characteristics of DBH in human CSF. DBH activity in CSF of Parkinsonian patients was lower than that of control patients. The properties of DBH in human CSF were similar to those in serum and adrenal medulla.     

Occurrence of Two Types of Ca2+-Dependent Protein Kinases in the Cytosol Fraction of the Brain

Abstract— Two types of Ca²⁺-dependent protein kinases were demonstrated and partially purified from the cytosol fraction of rat brain by DEAE-cellulose, Sephadex G-200, and calmodulin-affinity column chromatography, using endogenous proteins and chicken gizzard myosin light chains as substrates. The molecular weights of the enzymes were 88,000 (peak I) and 120,000 (peak II) on gel filtration. Peak I had no affinity for calmodulin, whereas peak II had a high affinity for it, with a K _a value of 16.7 n m . The K _a values of peaks I and II for Ca²⁺ were 2.4 and 1.6 μ m , respectively.     

The “happy puppet” syndrome in two siblings

Summary Disomic and trisomic cells of a patient with Down syndrome mosaic were used to study the effect of the additional chromosome 21 against an identical genetic background. The frequency of Ag staining and the participation in satellite associations were determined for each pair of acrocentric chromosomes. The additional chromosome 21 of the trisomic cells and its homologues proved to be regularly Ag positive. Therefore the trisomic cells showed more Ag positive chromosomes and more satellite associations per cell than the diploid cells. Thus, no compensation for the additional rRNA-gene dose could be found in the cells of the trisomic line.     

Effect of inhibitors of protein synthesis on rat liver spermidine N-acetyltransferase

The increase in spermidine N-acetyltransferase activity in rat liver produced by carbon tetrachloride was completely prevented by simultaneous treatment with inhibitors of protein and nucleic acid synthesis suggesting that the increase results from the synthesis of new protein rather than the release of the enzyme from a cryptic inactive form. Treatment with cycloheximide 2 h after carbon tetrachloride also completely blocked the rise in spermidine N-acetyltransferase seen 4 h later. Such treatment completely prevented the fall in spermidine and rise in putrescine in the liver 6 h after carbon tetrachloride confirming the importance of the induction of spermidine N-acetyltransferase in the conversion of spermidine into putrescine. When cycloheximide was administered to rats in which spermidine N-acetyltransferase activity had been stimulated by prior treatment with carbon tetrachloride or thioacetamide, the activity was lost rapidly showing that the enzyme protein has a rapid rate of turnover. The half-life for the enzyme in thioacetamide-treated rats was 40 min, whereas the half-life for ornithine decarboxylase (which is well known to turn over very rapidly) was 27 min. In carbon tetrachloride-treated rats the rate or protein degradation was reduced and the half-life of spermidine N-acetyltransferase was 155 min and that for ornithine decarboxylase was 65 min. It appears that three of the enzymes involved in the synthesis and interconversion of putrescine and spermidine namely, ornithine decarboxylase, S-adenosylmethionine decarboxylase and spermidine N-acetyltransferase have rapid rates of turnover and that polyamine levels are regulated by changes in the amount of these enzymes.     

Screening of microorganisms having high fumarase activity and their immobilization with carrageenan

Summary To develop an efficient method for continuous production of L-malic acid from fumaric acid using immobilized microbial cells, screening of microorganisms having high fumarase activity was carried out and cultural conditions of selected microorganisms were investigated. As a result of screening microorganisms belonging to the genera Brevibacterium, Proteus, Pseudomonas, and Sarcina were found to produce fumarase in high levels. Among these microorganisms Brevibacterium ammoniagenes, B. flavum, Proteus vulgaris, and Pseudomonas fluorescens were further selected for their high fumarase levels in the cultivation on several media. These 4 microorganisms were entrapped into a k-carrageenan gel lattice, and the resultant immobilized B. flavum showed the highest fumarase activity and operational stability.Cultural conditions for the fumarase formation and the operational stability of fumarase activity of immobilized B. flavum are detailed. Productivity for L-malic acid using immobilized B. flavum with k-carrageenan was 2.3 fold of that using immobilized B. ammoniagenes with polyacrylamide.Presented at the Annual Meeting of the Agricultural Chemical Society of Japan, Nagoya, April 3, 1978