In vitro transformation of cheno- and ursodeoxycholic acids and their 7-oleyl esters by human intestinal microflora

Chenodeoxycholic and ursodeoxycholic acid are used widely for the treatment of gallstones. A possible drawback to their utility is their conversion to lithocholic acid, which has displayed histotoxicity and mutagenicity. The 7-oleyl esters of cheno- and ursodeoxycholic acid are not degraded by fecal bacteria and may represent safer means of treatment.     

Cytogenetic biomonitoring of an Italian population exposed to pesticides: chromosome aberration and sister-chromatid exchange analysis in peripheral blood lymphocytes

Chromosome aberrations (CA) and sister-chromatid exchanges (SCE) were measured in lymphocytes of (A) 32 healthy individuals working in the flower industry and exposed to pesticides, (B) 32 individuals exposed as above and hospitalized for bladder cancer, and (C) 31 controls. Compounds to which floriculturists were exposed included 18 nitro-organic herbicides and fungicides, 9 nitro-organic fungicides, 12 organophosphate and organothiophosphate insecticides, 4 hydrocarbon derivative herbicides and 5 inorganic fungicides and insecticides. 150 and 70 metaphases per individual were scored for CA and SCE, respectively. A significant increase in the incidence of CA and SCE was observed in both exposed groups. Cancer patients showed the presence of rare rearrangements (dicentrics, rings and quadriradials) that were not observed in controls and were present at a lower frequency in healthy exposed people. Hyperdiploid and polyploid metaphases were also significantly increased in the 2 exposed groups compared to controls. Stratifying for age or smoking habits, although affecting the significance of individual data, did not change the substance of the results.     

Cloning and expression of a cDNA encoding a catalytically active fragment of calf thymus DNA polymerase alpha

A calf thymus cDNA expression library was constructed in the EcoRI site of lambda gt11 and probed with an antibody raised against calf thymus DNA polymerase alpha. Three classes of antibody-reactive clones were isolated. The largest class carried a 1.9 kilobase calf cDNA insert and expressed a 165-175 kilodalton beta-galactosidase:calf fusion protein which displayed DNA polymerase activity. The characteristic responses of the polymerase activity to alpha-specific inhibitors and antibodies identified the 1.9 kilobase cDNA as a sequence specifically derived from the structural gene encoding the pol alpha catalytic core.     

Identification of the pleiotropic sacQ gene of Bacillus subtilis.

The sacQ gene of Bacillus subtilis, a pleiotropic gene affecting the expression of a number of secreted gene products, has been identified as a small 46-amino-acid polypeptide. The increased expression of this polypeptide in strains carrying the sacQ36 allele, or in strains carrying the sacQ gene on a high copy plasmid, appears to be responsible for the phenotype of higher levels of proteases seen in these strains. A deletion of the sacQ gene had no apparent phenotype, indicating that it is not an essential gene.     

Correlation between soil characters and forest types: a study in multiple discriminant analysis

Multiple discriminant analysis is a useful multivariate technique in vegetation studies that can be employed for several purposes, even if the underlying statistical assumptions are not satisfied. An example of application of this method is discussed: multiple discriminant analysis was successfully used for evaluating the predictivity of forest types defined by numerical classification of vegetation data with respect to soil variables.Species nomenclature follows Pignatti (1982) for vascular plants and Augier (1966) for mosses.The research has been supported by the IDROSER (Bologna, Italy) and by the Italian C. N. R. (Grant no. 83.02548.04, resp. Prof. A. Pirola). We wish to thank Prof. E. Feoli, Prof. E. van der Maarel, Prof. L. Orlóci and Prof. A. Pirola for suggestions. We are also indebted to Dr N. Filippi who analyzed the soil samples.     

Isolation of a cDNA clone for chick intestinal apolipoprotein AI (Apo-AI) and its use for detecting apo-AI mRNA expression in several chick tissues

Three cDNA clones for chick apolipoprotein AI (Apo-AI), the major protein component of plasma high-density lipoproteins, have been isolated. The identity of the clones has been established first by screening a cDNA library in the pEX1 expression vector with anti-Apo-AI antibodies, second by Western blot analysis of the proteins expressed by positive clones. The use of the clone containing the largest, presumably full-size, cDNA insert (apo5C12) in molecular hybridization experiments confirms that apo-AI mRNA is expressed mainly in chick small intestine and liver. Furthermore, we provide evidence that brain, heart and skeletal muscle also synthesize significant amounts of apo-AI mRNA. The Southern-blot hybridization pattern of the restriction-enzyme-digested chick DNA with the apo5C12 DNA is consistent with there being a single copy of the apo-AI gene.     

Non-Michaelian kinetics of rabbit muscle uridine diphosphoglucose pyrophosphorylase

The kinetic properties of rabbit muscle uridine diphosphoglucose (UDP-Glc) pyrophosphorylase have been studied, in both directions, with respect to substrate saturation, product inhibition, and cation requirement for activity. The results demonstrate that UDP-Glc pyrophosphorylase is a non-Michaelian enzyme: the synthetic reaction is characterized by a marked inhibition by glucose-1-phosphate (at concentrations higher than 0.3 mM) and by an hyperbolic saturation for UTP. In the reverse reaction, instead, the saturation function for UDP-Glc is hyperbolic and that for inorganic pyrophosphate is sigmoid, with a high Hill coefficient of (nH) 2.5. The study of the metal requirement indicates a distinctive ability of cations to stimulate the reactions of synthesis and degradation of the sugar nucleotide and a different stoichiometry of the metal chelates involved. The reaction mechanism is of the ordered-sequential type and the data of product inhibition allowed the identification of glucose-1-phosphate as the first substrate bound and UDP-Glc as the last product released. The inhibition pattern by UDP-Glc gives evidence for cooperativity also in the binding of this molecule.     

Cloning structural gene sacB, which codes for exoenzyme levansucrase of Bacillus subtilis: expression of the gene in Escherichia coli.

A clone bearing the structural gene sacB, coding for the exoenzyme levansucrase, was isolated from a library of Bacillus subtilis DNA that was cloned in phage lambda charon 4A on the basis of the transforming activity of the chimeric DNA. This lambda clone also was found to contain the sacR and smo loci. Subcloning the sacB-sacR region in plasmid pBR325 resulted in a clone which directed levansucrase synthesis in Escherichia coli. The nucleotide sequence coding for the secreted protein was localized on the physical map of the cloned DNA.     

Effects of 3,5-Dihalogenated-4-hydroxybenzonitriles on the Activity of Mitochondria From White Potato Tubers

Effects of the herbicide 3,5-diiodo-4-hydroxybenzonitrile (ioxynil), and its dibromo and dichloro analogs, upon the respiration of mitochondria isolated from white potato tubers (Solanum tuberosum L.) were investigated. Mitochondrial-mediated oxygen uptake was monitored polarographically with a platinum oxygen electrode.