Elevated polyamine levels in erythrocytes of SLC:ICR mice inoculated with ehrlich ascites carcinoma cells

Ehrlich ascites carcinoma cells (4×10⁵ cells/mouse) were inoculated intraperitoneally in 7-week-old SLC:ICR mice, and polyamine levels in peripheral erythrocytes and in ascites cells were determined periodically. Polyamine levels in peripheral erythrocytes increased linearly until 10 days after cell inoculation, while ascites cells showed exponential growth.The effect of carbazilquinone on cellular growth and polyamine levels in erythrocytes was also studied. When 1 or 2mg/kg of carbazilquinone was injected intraperitoneally on day 4 or on day 7, cellular growth was suppressed and the survival time of the mice was lengthened. The polyamine levels in erythrocytes were also markedly decreased 3 days after the carbazilquinone injection.These results suggest that the polyamine levels in peripheral erythrocytes are closely related to the cellular growth of Ehrlich ascites carcinoma cells.     

On the role of IS1 in the formation of hybrids between the bacteriophage P1 and the R plasmid NR1

Summary The genomes of bacteriophage P1 derivatives carrying drug resistance genes derived from an R plasmid NR1 were analysed by restriction cleavage and be DNA-DNA hybridization. Two representatives of a class of oversized P1CmSmSu phages were identified as P1 carrying the entire r-determinant of NR1 together with its two flanking, directly repeated IS1. In one case the r-determinant insertion is carried at the site of the residential IS1 of P1, in the other case it is transposed into another region of the P1 genome. Models postulate that the first type resulted from reciprocal recombination within IS1 elements and that the formation of the second type of P1-R hybrid depended both on IS1 mediated transposition and reciprocal recombination. Plaque forming P1Cm or P1CmSm phages are explained as IS1 mediated deletion derivatives of P1CmSmSu, although an alternative model postulates that sometimes P1Cm phages might result from two consecutive transposition events of only one IS1 without involving reciprocal recombination. Secondary P1 derivatives carrying only one IS1 at the site of the original r-determinant or of Cm insertions into P1 must have been produced by reciprocal recombination between the two IS1 flanking the insertions. An implication from this study, that any genetic material carried adjacent to an IS1 element may undergo passive transposition, is discussed.     

Electron donor pool of photosystem II in Tris-washed chloroplasts in a study of low temperature delayed fluorescence

Transient time courses ("induction") and the intensity of thedelayed fluorescence of chlorophyll a (measured between 0.1and 3.9 msec after a 0.9 msec excitation period) were studiedwith a phosphoroscope at temperatures between 40 and –170°Cin Tris-washed chloroplasts. Tris-washing of chloroplasts changed the temperature dependenciesof the induction and the intensity of the delayed fluorescence.From the analysis of the induction each photosystem II reactioncenter appears to be linked to a donor pool which can supplyone electron to the acceptor pool in Tris-washed chloroplasts. An artificial electron donor, diphenylcarbazide affected thedelayed fluorescence above –100°C evidence that electronsare donated to photosystem II in at least two different ways. An electron transport inhibitor, 3-(3',4'-dichlorophenyl)-l,l-dimethylurea,changed the induction of the delayed fluorescence at temperaturesabove –60°C. The temperature dependence of the electron transport in thevicinity of photosystem II was characterized from these results. (Received May 27, 1980; )     

{alpha}-Aminoisobutyric acid : A probable competitive inhibitor of conversion of 1-aminocyclopropane-1-carboxylic acid to ethylene

Of 16 compounds related to 1-aminocyclopropane-1-carboxylicacid (ACC), aminoisobutyric acid (AIB) inhibited the productionof endogenous ethylene in the cotyledonary segments of cocklebur(Xanthium pennsylvanicum Wallr.) seeds most strongly. AIB at4 mM inhibited the formation of ethylene by about 50%, althoughthe O₂ uptake of the segments was not affected even at 20 mM.AIB also inhibited ethylene formation in the stem segments ofetiolated pea (Pisum sativum L. cv. Alaska) seedlings. Kineticanalysis with cell free extracts from etiolated pea shoots revealedthat AIB competitively inhibits the conversion of ACC into ethylene. (Received May 26, 1980; )     

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of bovine serum albumin oligomers produced by lipid peroxidation.

The oligomers of bovine serum albumin were produced by controlled reaction with peroxidizing linoleic acid to examine their possible utility as calibration proteins insodium dodecyl sulfate-polyacrylamide gel electrophoresis. The polymerization was effected in reaction mixtures containing linoleic acid undergoing peroxidation in the presence of ascorbic acid, and conditions that yield soluble oligomers with a wide molecular weight distribution were established. The interaction of these soluble oligomers with sodium dodecyl sulfate exhibited a binding isotherm indistinguishable from that obtained with bovine serum albumin. Furthermore, sodium dodecy sulfate-polyacrylamide gel electrophoresis of the albumin oligomers conformed to the empirical relation of molecular weight to mobility that pertains to the use of these oligomers as standard molecular weight markers.     

Thermodynamic analysis of the nonspecific interaction of sodium dodecyl sulfate with swollen Bio-Gel beads

In frontal gel chromatography on Bio-Gel P-2, sodium dodecyl sulfate (SDS) at the concentrations below its critical micelle concentration (cmc) showed anomalously high partition coefficients (Kav obs) indicative of strong interactions with the swollen gel phase; further, Kav obs was found to increase with concentration and temperature. This preferential partition of SDS in the Bio-Gel phase was analyzed in terms of the transfer free energy of SDS from the mobile phase (0.1 M NaCl) to the swollen Bio-Gel phase. The results showed that the overall transfer process is primarily governed by hydrophobic free energy arising from the anomalous nature of hydrated water in the gel matrix; that is, in highly hydrated water "iceberg" formation is evidently limited and the hydrophobic free energy is accordingly lowered, resulting in the preferential partition of SDS in the swollen Bio-Gel phase. The increase in the negativity of transfer free energy with concentration, though relatively small, indicated a definite tendency for the formation of SDS clusters in the gel phase. Finally, a model illustrating the states of SDS molecules in the gel matrix is presented, which may also be pertinent to SDS-protein and SDS-amylose complexes.     

Chemical modification of neamine

The aminocyclitol antibiotic neamine has been modified by changing the configuration of one or two hydroxyl groups of the aminocyclitol moiety to elucidate the relationship between configuration and antimicrobial activity. 5-Epi-, 6-epi-, and 5,6-diepineamine have been prepared and their antimicrobial activity has been determined against several micro-organisms.     

Inhibition of the synthesis of microbial cellulose by coumarin

Coumarin, a specific inhibitor of the biosynthesis of celluloseof higher plant cell walls, inhibited the cellulose formationof Acetobacter xylinum. The degree of inhibition reached 55%in the presence of 1 mM coumarin, which causes 70% inhibitionin the case of plant cellulose. (Received April 12, 1976; )     

{beta}-1,4-Glucan occurring in homogenate of Phaseolus aureus seedlings. Possible nascent stage of cellulose biosynthesis in vivo

A small amount of cytoplasmic ß-1,4-glucan, whichmight be involved in the synthesis of cellulose in the cellwall, was found in the homogenate prepared from the hypocotylsof seedlings of Phaseolus aureus. Upon hydrolysis by cellulaseof the 20,000?g pellet from the cytoplasmic fraction of segmentsincubated in a [¹⁴C]-glucose solution, [¹⁴C]-cellobiose wasproduced, with specific radioactivities 3 to 10 times greaterthan those of the cellobiose from cellulose in the cell wallat various incubation periods. The incoporation of radioactivityfrom [¹⁴C]-glucose into this cytoplasmic ß-1,4-glucanwas therefore faster than that into cellulose constituting thecell wall. Hence, it seemed that the former ß-1,4-glucancould be turned over. To examine whether the- cytoplasmic ß-1,4-glucanis carried by some subcellular components, cytoplasmic ß-1,4-glucanin the cell was fractionated by differential centrifugation,two enzyme activities being measured as the markers of subcellularcomponents. The distribution of ß-1,4-glucan was similarto that of UDPG-glucosyltransferase activity but not to thatof IDP-ase activity. The result suggests that the cytoplasmicß-1,4-glucan has some relation to plasma membranes. Coumarin, known as a specific inhibitor for the biosynthesisof cellulose in plant cells, was shown to inhibit the incorporationof radiocarbon from [¹⁴C]-glucose into cytoplasmic ß-1,4-glucanto the same extent as that into cellulose in the cell wall ofthe hypocotyls. ¹ Present address: Department of Biological Science, TohokuUniversity, Kawauchi, Sendai 980, Japan. (Received May 31, 1976; )     

Chemical modification of aminocyclitol antibiotics

The aminocyclitol antibiotic neamine has been chemically modified at the hydroxyl group on C-6 of the 2-deoxystreptamine moiety. The partially acetylated neamine derivatives, 6,3′,4′-tri-O-acetyl- (3) and 5,3′,4′-tri-O-acetyl-1,3,2′,6′-tetra-N-(ethoxycarbonyl)neamine (4), were prepared by random hydrolysis of the 5,6-O-ethoxyethylidene derivative (2), followed by chromatographic purification. Condensation of 4 and 2,3,5-tri-O-benzoyl-d-ribofuranosyl chloride led to 6-O-(β-d-ribofuranosyl)neamine (7). Analogous condensation of 4 with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide or 2,3,4,6-tetra-O-acetyl-α-d-galactopyranosyl bromide afforded the corresponding 6-O-(d-hexopyranosyl)neamines.