Genotoxicity of carcinogenic N-nitrosopropylamine derivatives in the hepatocyte primary culture/DNA-repair test

The genotoxicity of N-nitrosodipropylamine, 8 of its oxidized derivatives and N-nitroso-2,6-dimethylmorpholine was examined in the hepatocyte primary culture (HPC)/DNA repair test. Nine N-nitrosamines which are known to be carcinogenic and mutagenic were clearly positive in the HPC/DNA-repair test. N-Nitroso(2,3-dihydroxypropyl) (2-hydroxypropyl)amine did not elicit DNA repair, but showed a borderline mutagenic response in the Salmonella/microsome test. Thus, the HPC/DNA-repair test displays a comparable capacity to the bacterial mutagenesis test for detecting the genotoxic effects of this class of carcinogens.     

Differentiation of Photorespiratory Activity between Mesophyll and Bundle Sheath Cells of C4 Plants II. Peroxisomes of Panicum miliaceum L.

Peroxisomes were isolated by sucrose density gradient centrifugationfrom mesophyll and bundle sheath protoplasts of a C₄ plant,Panicum miliaceum L. The equilibrium density in the gradientwas 1.25 for bundle sheath peroxisomes and 1.23 for mesophyllperoxisomes, the former density being similar to that of peroxisomesof wheat mesophyll protoplasts. Photorespiratory and other microbody enzymes were assayed forthe peroxisomes of P. miliaceum to detect possible differentiationat an enzyme level. The specific activities of photorespiratoryenzymes, except for hydroxypyruvate reductase, in bundle sheathperoxisomes were 40–60% of those in wheat peroxisomes,when compared on a protein basis, and only 20–30% in mesophyllperoxisomes. However, peroxisomes from both cell types containedsignificant levels of all the enzymes involved in the photorespiratoryglycolate pathway, when compared with castor bean glyoxysomes.The activity of hydroxypyruvate reductase in the peroxisomesof P. miliaceum was comparable to or higher than that in wheatperoxisomes. Two ß-oxidation enzymes and urate oxidasewere detected in the peroxisomes in a similar level to thatin wheat peroxisomes. These results suggest that the peroxisomes of mesophyll andbundle sheath cells of P. miliaceum are essentially similarto those of C₃ plants, and that they cannot be differentiatedexcept for a difference in equilibrium density in a sucrosegradient. (Received December 24, 1984; Accepted April 9, 1985)     

Genome type analysis of adenovirus type 4 isolates, recently obtained from clinically different syndromes in some areas in Japan

DNA cleavage analyses with EcoRI, HindIII and BamHI were carried out to investigate genome types of recent Ad 4 isolates obtained from acute respiratory disease (8 strains), and ocular disease (11 strains) in Japan. DNA cleavage patterns of all 19 isolates studied were identical regardless of whether they were recovered from respiratory tract or conjunctiva, but were distinct from that of the prototype strain.     

Characterization of antisera to 2-hydroxyestradiol and 4-hydroxyestradiol using 6-(O-carboxymethyl)oxime- and 17-hemisuccinate-bovine serum albumin conjugates and radioimmunoassay

For radioimmunoassay of the catechol estrogens, four hapten-bovine serum albumin (BSA) conjugates were prepared from 6-oxo-2-hydroxyestradiol 6-(O-carboxymethyl)oxime, 2-hydroxyestradiol 17-hemisuccinate, 6-oxo-4-hydroxyestradiol 6-(O-carboxymethyl)oxime and 4-hydroxyestradiol 17-hemisuccinate by coupling with BSA, employing the mixed anhydride method. The antisera elicited in rabbits by immunization with these antigens showed high affinity and specificity for 2-hydroxyestradiol or 4-hydroxyestradiol with cross-reactivities to a few structurally related estrogens. The specificity of antisera obtained is discussed in relation to the site of attachment of the hapten to BSA.     

Ontogenesis of gastrin cells in the pyloric antrum and duodenum of the mouse

Summary Ontogenesis of gastrin cells was studied in the pyloroduodenal mucosa of the mouse using anti-human G17 serum, R-1301, and anti-human G34(1–15) serum, R-2703. R-1301-immunostained cells first appeared in the pyloric mucosa of 14-day-old fetuses. Cells stained with both R-1301 and R-2703 appeared immediately after birth, and gradually increased in number to the adult level. Most R-1301-reactive cells were also reactive to R-2703, whereas some cells that reacted with R-1301 exhibited very weak or no reaction with R-2703. The discrepancy between these two immunoreactivities is discussed.In the duodenum, a considerable number of R-1301-reactive cells were present from the perinatal stage and through out adult development. A few R-2703-reactive cells were seen in the duodenum of young mice but not of the adult.     

Human indolylamine 2,3-dioxygenase. Its tissue distribution, and characterization of the placental enzyme.

The presence of indolylamine 2,3-dioxygenase was examined in human subjects by determining its activity with L-tryptophan as substrate. Enzyme activity was detected in various tissues, and was relatively high in the lung, small intestine and placenta. Human indolylamine 2,3-dioxygenase, partially purified from the placenta, had an Mr of about 40 000 by gel filtration and exhibited a single pI of 6.9. The human enzyme required a reducing system, ascorbic acid and Methylene Blue, for maximal activity and was able to oxidize D-tryptophan, 5-hydroxy-L-tryptophan as well as L-tryptophan, but kinetic studies indicated that the best substrate of the enzyme was L-tryptophan.     

Production of ethyl acetate from dilute ethanol solutions by Candida utilis

The conversion of ethanol to ethyl acetate has an advantage as a method of ethanol recovery since ethyl acetate is amenable to simple solvent extraction. The potential of Candida utilis in this conversion was studied. The kinetics of accumulation of ethanol and ethyl acetate in glucose-grown C. utilis showed that ester formation resulted from ethanol utilization under appropriate aeration and was inhibited by Fe(3+) supplementation. Candida utilis converted ethanol to ethyl acetate optimally at pH 5.0-7.0. The five-hour rate of ester production increased as the ethanol concentration increased to 10 g/L, and rapidly declined to zero at concentrations exceeding 35 g/L. Thus, C. utilis has potential to recover dilute ethanol in the form of ethyl acetate.     

Highly potent and specific inhibitors of human renin

We designed aldehyde derivatives of small peptides representing the C-terminal portion of angiotensin I sequence as an inhibitor of human renin. Among compounds that we synthesized, benzyloxycarbonyl (Z)-Phe-His-Leucinal (compound V), Z-Pro-Phe-His-Leucinal (Compound IV) and Z-[3-(1'-naphthyl)Ala]-His-Leucinal (compound VII) markedly inhibited human renin (IC50, 7.5 X 10(-7), 3.2 X 10(-7) and 8.0 X 10(-8) mol/l, respectively). Compound VII was shown to be noncompetitive (Ki = 2.4 X 10(-7) mol/l). It did not inhibit either cathepsin D or pepsin. Compound V had slight or no inhibitory effect at the concentration of 10(-5) mol/l on six animal renins except for monkey and rabbit renins. Results obtained show that these aldehyde compounds are highly selective and species specific inhibitors for human and monkey renins.     

Glucagon-related peptides in the rat hypothalamus

Summary Immunohistochemically, nerve fibers and terminals reacting with anti-N-terminal-specific but not with anti-C-terminal-specific glucagon antiserum were observed in the following rat hypothalamic regions: paraventricular nucleus, supraoptic nucleus, anterior hypothalamus, arcuate nucleus, ventromedial hypothalamic nucleus and median eminence. Few fibers and terminals were demonstrated in the lateral hypothalamic area and dorsomedial hypothalamic nucleus. Radioimmunoassay data indicated that the concentration of gut glucagon-like immunoreactivity was higher in the ventromedial nucleus than in the lateral hypothalamic area. In food-deprived conditions, this concentration increased in both these parts. This was also verified in immunostained preparations in which a marked enhancement of gut glucagon-like immunoreactivity-containing fibers and terminals was observed in many hypothalamic regions. Several immunoreactive cell bodies were found in the ventromedial and arcuate nuclei of starved rats. Both biochemical and morphological data suggest that glucagon-related peptides may act as neurotransmitters or neuromodulators in the hypothalamus and may be involved in the central regulatory mechanism related to feeding behavior and energy metabolism.