Increased podophyllotoxin production in Podophyllum hexandrum cell suspension cultures after feeding coniferyl alcohol as a β-cyclodextrin complex

Summary Cell suspension cultures, derived from roots of Podophyllum hexandrum Royle (Berberidaceae), accumulate podophyllotoxin. In this study the use of -cyclodextrin in feeding the poorly water-soluble precursor coniferyl alcohol to these cultures is described. By complexation with -cyclodextrin, a solution of 3 mM coniferyl alcohol could be fed, resulting in enhanced podophyllotoxin accumulation. The same concentration of non-complexed suspended coniferyl alcohol had only little effect on the podophyllotoxin accumulation. -Cyclodextrin itself was proven to be non-toxic for the cells. It did not influence the podophyllotoxin content and it was not metabolized or used as a carbon source by the cells. For comparison, coniferin, the water-soluble -D-glucoside of coniferyl alcohol, was also fed in the same concentration. The effect of coniferin on the podophyllotoxin accumulation was stronger than that of coniferyl alcohol complexed with -cyclodextrin, but coniferin is not commercially available.Abbreviations -CD -cyclodextrin - NAA naphthaleneacetic acid     

Somatic hybrid plants produced by electrofusion between dihaploid potatoes: BF15 (H1), Aminca (H6) and Cardinal (H3)

In order to regenerate somatic hybrids, mesophyll protoplasts from a dihaploid potato, BF15 (H1), were electrofused with those from two other dihaploid clones, Aminca (H6) and Cardinal (H3). Determination of the ploidy level by flow cytometry showed that 10% of plants regenerated from the fusion experiment with BF15 + Aminca were diploids, 14% triploids, 63% tetraploids and very few were mixoploids or had a higher ploidy level. Using morphological markers and vigour in plant growth, we were able to recover a total of 24 somatic hybrid plants, respectively 20 and 4 hybrids (accounting for 12% and 13% of regenerants) from the fusions BF15 + Aminca and BF15 + Cardinal. Most of the somatic hybrids were at the expected tetraploid level (2n=4x=48). The hybrid nature was confirmed by examining isoenzyme patterns for malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICD).     

Dépistage de l'alcoolisme en médecine familiale: étude pilote de l'association du Michigan Alcoholism Screening Test et le dosage de la gamma-glutamyltransférase sérique.

When used simultaneously, are laboratory and psychosocial methods of screening helpful to detect alcoholism in general practice? To examine this issue, systematic screening with a self-administered Michigan Alcoholism Screening Test and measurement of the plasma gamma-glutamyltransferase level was offered to 435 clients at a family medicine clinic. Whenever a positive finding was obtained the client was free to undergo a more detailed evaluation to confirm the diagnosis. A total of 200 subjects (126 women, 74 men) agreed to undergo screening. The results do not appear to lead to practical consequences among women, in whom no case was identified. In contrast, in the male population a rate of first detection of 9.5% (seven cases) should encourage such screening for alcoholism in family medicine.     

Infectivity inhibition of HIV prototype strains by antibodies directed against a peptide sequence of mycoplasma

Antibodies prepared against a peptide corresponding to the site of cyto-adherence of Mycoplasma genitalium adhesine inhibit or reduce the infectivity of the HIV-1BRU and HIV-2ROD strains of Human Immunodeficiency Virus in lymphoid cells. These results strengthen the hypothesis that some mycoplasmas may play an important part in HIV replication and pathogenicity.     

Determination of the intracellular protein thiol distribution of hepatocytes using monobromobimane derivatisation of intact cells and isolated subcellular fractions

The derivatisation of intact rat hepatocytes with monobromobimane resulted in rapid labelling of accessible protein thiols in several subcellular fractions. The derivatisation procedure did not cause acute cytotoxicity, nor did it alter the buoyant densities of the fractions or their gross protein compositions. Quantitation of the fluorescence irreversibly associated with the fractions demonstrated considerable intracellular heterogeneity in this pool of thiols. Values were highest in cytosol (ca. 90 nmol/mg protein), intermediate in microsomes (ca. 65 nmol/mg protein) and mitochondria (ca. 45 nmol/mg protein) and lowest in a crude fraction containing both nuclei and plasma membrane (ca. 35 nmol/mg protein). Similar values were obtained from microsomes and cytosol derivatised after fractionation but there were significant increases of ca. 100% in corresponding values from isolated mitochondria and the nuclear/plasma membrane fraction. These results are discussed in terms of the dynamic fluxes in monobromobimane protein thiols during fractionation and the applicability of this noninvasive method to studies of the mechanism(s) of toxicity of reactive xenobiotics and the role(s) of protein thiols in normal cellular function.     

Detection and quantification of patulin and griseofulvin by high pressure liquid chromatography in different strains of Penicillium griseofulvum Dierckx

Patulin and griseofulvin production by twelve strains ofPenicillium griseofulvum Dierckx, eleven of which were isolated from pistachio (Pistacia vera) nuts and the other was supplied by the Spanish Collection of Type Culture, was investigated. Six strains of the eleven isolated had ability to produce patulin and griseofulvin in Yes medium. All the strains studied had no ability to produce patulin in Wickerham medium. Griseofulvin production was significant in both media but higher in Wickerham. These metabolites were separated and determined in the chloroform extracts of cultures by high performance liquid chromatography with ultraviolet detection. The best conditions were: acetonitrile — water (45∶55) as mobile phase, a flow rate of 2.0 mL/min and a μ Bondapack C₁₈ column.     

Effect of intraarterial somatostatin infusion on SMA blood flow

Experiments were carried out on anaesthetized cats to study the effect of somatostatin on the mesenteric circulation. Intraarterial infusions of somatostatin were applied into the superior mesenteric artery. The effect of atropine, propranolol and phentolamine were investigated. Catecholamine release or uptake of the mesenteric vascular bed during somatostatin infusions were also measured. We found dose dependent vasodilatory effect of somatostatin on the mesenteric vasculature that was not influenced by atropine and by the adrenoreceptors or by denervation. A direct effect of somatostatin on the vascular smooth muscle membrane is assumed.     

Aldosterone nuclear receptors in kidneys of chick embryo

We have studied the properties of the nuclear receptors for aldosterone in kidneys of chick embryo. Aliquots of 0.4 M KCl nuclear extracts were incubated with [3H]aldosterone with or without 1 microM RU28362, a potent glucocorticoid analog. Scatchard analyses of binding data revealed two classes of binding sites with Ka of 0.26 and 0.03 X 10(9) M-1 and Nmax of 330 fmol and 620 fmol/mg DNA respectively. In presence of RU28362, however, we observed only a single class of binding sites with a Ka of 1.02 X 10(8) M-1 and a Nmax of 90 fmol/mg DNA. Competition studies performed in presence of RU28362 showed that aldosterone was the more effective competitor followed by corticosterone, progesterone, deoxycorticosterone, dexamethasone, cortisol, triamcinolone acetonide and cortisone. The nuclear complexes had a sedimentation coefficient in the area of 8 S which changed to 4-5 S in the presence of 0.4 M KCl. This effect of KCl was prevented by the addition of 10 mM sodium molybdate. Always in the presence of the glucocorticoid analog, by DEAE-c chromatography we observed a major specific aldosterone-binding fraction which was eluted with 0.2 M KCl. This fraction sedimented at 8.4 S in the absence of sodium molybdate and KCl. In the absence of RU28362, DNA-c columns retained only a small portion of the nuclear complexes which were eluted with KCl. These complexes sedimented, on sucrose gradient, at 4.6 and 3.1 S, whereas those which did not bind to DNA-c had a sedimentation coefficient of 8 S. In the presence of RU28362, the majority of bound [3H]aldosterone remained in the column flow-through fraction; when this fraction was further analyzed on DEAE-c, complexes were eluted with 0.2 and 0.3 M KCl. These data indicate that nuclear receptors for aldosterone are present in small number in kidneys of chick embryo and that they are mostly in the 8 S form.