Participation and Properties of Lipoxygenase and Hydroperoxide Lyase in Volatile C6-Aldehyde Formation from C18-Unsaturated. Fatty Acids in Isolated Tea Chloroplasts

Isolated tea chloroplasts utilized linoleic acid, linolenicacid and their 13-hydroperoxides as substrates for volatileC₆-aldehyde formation. Optimal pH values for oxygen uptake,hydroperoxide lyase and the overall reaction from C₁₈-fattyacids to C₆-aldehydes were 6.3, 7.0 and 6.3, respectively. Methyllinoleate, linoleyl alcohol and -linolenic acid were poor substratesfor the overall reaction, but linoleic and linolenic acids weregood substrates. The 13-hydroperoxides of the above fatty acidsand alcohol also showed substrate specificity similar to thatof fatty acids. Oxygen uptakes (relative V_max) with methyl linoleate,linoleyl alcohol, linolenic acid, -linolenic acid and arachidonicacid were comparable to or higher than that with linoleic acid.In winter leaves, the activity for C₆-aldehyde formation fromC₁₈-fatty acids was raduced to almost zero. This was due tothe reduction in oxygenation. The findings presented here provideevidence for the involvement of lipoxygenase and hydroperoxidelyase in C₆-aldehyde formation in isolated chloroplasts. (Received July 11, 1981; Accepted November 5, 1981)     

Late replicating X chromosomes in human triploidy.

The status of X-chromosome replication was studied in twenty-seven 69,XXY and nine 69,XXX human triploids in which the parental origin of the additional haploid set was known from the study of chromosome heteromorphisms. Among the 69,XXY triploids, fourteen had no late replicating X, two had one late replicating X in all cells examined, and eleven had two populations of cells, one with late replicating X chromosome, and one without any. Among the 69,XXX triploids, four had a single late replicating X, and five had two populations of cells, one with one late replicating X, and one with two late replicating X chromosomes. There was no correlation between the parental origin of the triploidy and the type of X-chromosome inactivation. However the number of late replicating X chromosomes was significantly lower in cultures grown from fetal tissue when compared with those grown from extra-embryonic tissue. In cultures derived from extra-embryonic tissue there was a significant correlation between the gestational age of the sample and the proportion of late replicating X chromosomes. The older the specimen, the greater the number of late replicating X chromosomes.     

Fungal contamination and mycotoxin-producing potential of dried beans

A total of 604 samples of about 7 different types of beans was examined to determine their mycological profiles, and suitability for use as solid substrates for mycotoxin production.All of the samples were collected from bean jam makers in Tokyo by the official food examiners.Genera Penicillium and Aspergillus were predominant, and genus Wallemia was also found commonly in all types of beans.Mycotoxin-producing Aspergillus strains were isolated from 52 samples of beans, approximately 9% of the total. The highest incidence of toxigenic Aspergillus (14.1%) was found in kidney beans. Red beans and peas inoculated with Aspergillus ochraceus were found to produce about 7 to 8 times more toxin than was obtained in a liquid medium, and red beans inoculated with A. versicolor produced more toxin than was obtained in yeast extract sucrose broth. Green peas inoculated with Fusarium graminearum produced about 8 times more T-2 toxin than was obtained in 1% peptone containing Czapek solution under comparable culture conditions.     

Marijuana exposure in vivo and human lymphocyte chromosomes.

Sequential chromosome examinations of peripheral lymphocte cultures were carried out on 21 adult male volunteers who smoked natural blend marijuana cigarettes containing about 1%, 2%, or no delta9-THC. For a limited number of subjects, blood samples from a single venipuncture were cultured independently in two cytogenetic laboratories, and later the slides were exchaged for re-analysis. There were significant differences between laboratories in the absolute break frequencies recorded. These inter-laboratory differences were demonstrated for both techniques of cell culture and metaphase analysis. Neither laboratory found a statistically significant increase in break frequencies asssociated with marijuana smoking. The present study, therefore, failed to detect a measurable effect of marijuana smoking on chromosomal aberrations in subjects experienced in the use of the drug.     

In vivo and in vitro characterization of the secA gene product of Bacillus subtilis.

The putative amino acid sequence from the wild-type Bacillus subtilis div+ gene, which complements the temperature-sensitive div-341 mutation, shares a 50% identity with the sequence from Escherichia coli secA (Y. Sadaie, H. Takamatsu, K. Nakamura, and K. Yamane, Gene 98:101-105, 1991). The B. subtilis div-341 mutant accumulated the precursor proteins of alpha-amylase and beta-lactamase at 45 degrees C as in the case of sec mutants of E. coli. The div-341 mutation is a transition mutation causing an amino acid replacement from Pro to Leu at residue 431 of the putative amino acid sequence. The B. subtilis div+ gene was overexpressed in E. coli under the control of the tac promoter, and its product was purified to homogeneity. The Div protein consists of a homodimer of 94-kDa subunits which possesses ATPase activity, and the first 7 amino acids of the putative Div protein were found to be subjected to limited proteolysis in the purified protein. The antiserum against B. subtilis Div weakly cross-reacted with E. coli SecA. On the other hand, B. subtilis Div could not replace E. coli SecA in an E. coli in vitro protein translocation system. The temperature-sensitive growth of the E. coli secA mutant could not be restored by the introduction of B. subtilis div+, which is expressed under the control of the spac-1 promoter, and vice versa. The B. subtilis div+ gene is the B. subtilis counterpart of E. coli secA, and we propose that the div+ gene be referred to as B. subtilis secA, although Div did not function in the protein translocation system of E. coli.     

Splenic macrophages enhance prolactin-induced progestin secretion from mature rat granulosa cells in vitro.

The effect of splenic macrophages on in vitro progestin secretion (the sum of the progesterone and 4-pregnen-20 alpha-ol-3-one concentrations in the medium) from mature rat granulosa cells was examined by means of co-culture techniques. When splenic macrophages (3.0 x 10(5) cells/ml) obtained from adult female rats on the evening of proestrus (1800 h) were added to granulosa cells (1.5 x 10(5) cells/ml) and co-cultured for 96 h in the absence of prolactin (PRL), progestin secretion from granulosa cells did not change. However, co-culture of granulosa cells with the macrophages in the presence of PRL (2 micrograms/ml) significantly enhanced progestin secretion after 48 h of culture. This stimulatory effect on progestin secretion was observed only when the number of macrophages added was more than twice the number of granulosa cells. On the other hand, splenic macrophages obtained on the evening of diestrus had no effect on progestin secretion from granulosa cells even in the presence of PRL. These results suggest that splenic macrophages can enhance PRL action so as to stimulate progestin secretion from granulosa cells and that this function of splenic macrophages varies during the estrous cycle.     

Protoclonal variation of plant regeneration in rice

Protoplasts were isolated from callus derived from a single homozygous seed of Oryza sativa L. var. Norin 8. Thirty protoclones were randomly selected and these showed variation in regeneration frequency ranging from 0–87% with an average of 52%. The potential for regeneration of each protoclone as reflected in the regeneration frequency was analyzed five times over a period of 250 days and showed that the protoclones can be classified into three types, namely: protoclones with high regeneration frequency; protoclones with low regeneration frequency, both of which maintained their respective levels of regeneration potential; and protoclones with gradually decreasing regeneration frequency. Secondary protoclones established from protoplasts isolated from some of these protoclones and regenerated 2–3 times for a period of 120 days also showed further reduction in regeneration frequency. The polypeptide composition analyzed by two dimensional gel electrophoresis suggests the presence of specific polypeptides related to regeneration potential. Analysis of ploidy level based on plant morphology and pollen size suggests the predominance of tetraploids among the regenerated plants.     

Effect of addition of polyethyleneimine on thermal stability and activity of glucose dehydrogenase

When polyethyleneimine (PEI), a water-soluble cationic polymer, was added to solutions of glucose dehydrogenase (GDH) from Bacillus megaterium IWG3 at a molar ratio of PEI to GDH greater than 10, the thermal stability of GDH markedly increased. By addition of PEI, the rate of GDH-catalysed oxidation of -d-glucose increased in a low concentration range of NAD⁺ and NADP⁺ and the Michaelis constants and inhibition constants for both NAD⁺ and NADP⁺ decreased. These results suggested that negatively charged GDH interacts with cationic water-soluble polymers to form conjugates by electrostatic attraction, and also that negatively charged coenzymes are adsorbed by the polymers, resulting in enrichment of the coenzymes in the vicinity of GDH. Addition of PEI was also found to be effective for preventing the denaturation of GDH by acrylamide.Correspondence to: M. Teramoto     

Local formation and degradation of endothelin-1 in guinea pig airway tissues

Endothelin(ET)-1 and big ET-1 caused potent and sustained constriction of isolated guinea pig bronchus. The response to ET-1 was enhanced by phosphoramidon in a simple dose-related manner (0.01-1000 microM), while the response to big ET-1 was enhanced at lower doses (0.01-0.1 microM) but was suppressed at higher doses (100-1000 microM) of phosphoramidon. Big ET-1, when given intravenously (i.v.) to anesthetized guinea pigs, increased both bronchopulmonary inflation pressure and mean arterial blood pressure (2.5, 5, 10 nmol/kg i.v.). The pressor response to big ET-1 was attenuated by phosphoramidon dose-relatedly, while the pulmonary response was modified in a complex fashion composed of delayed onset and prolonged duration of action. These results suggest that ET converting as well as degrading enzymes coexist in the airway tissue and both enzymes are sensitive to phosphoramidon, so that phosphoramidon acts bifunctionally to reduce and stimulate the airway responses to big ET-1.