Evidence that 2-allyl-2-isopropylacetamide, phenobarbital and 3,5-diethoxycarbonyl-1,4-dihydrocollidine induce the same cytochrome P450 mRNA in chick embryo liver

The induction of cytochrome P450 in chick embryo liver has been studied using three different porphyrinogenic drugs, 2-allyl-2-isopropylacetamide, 3,5-diethoxycarbonyl-1,4-dihydrocollidine and phenobarbital. Pulse-labelling studies have shown that for each drug the cytochrome P450 synthesized either in ovo or in a wheat germ translation system reacted immunologically with antibody raised against the purified 2-allyl-2-isopropylacetamide-induced enzyme (Mr = 50000). To investigate whether this is due to the three drugs inducing the same protein or different proteins with common immunological determinants, nucleic acid hybridization studies have been carried out using a recently characterised 2-allyl-2-isopropylacetamide-induced cytochrome P450 cloned cDNA probe [Brooker, J. D. et al. (1982) Eur. J. Biochem. 129, 325-333]. It has been shown that the mRNA induced by each drug hybridizes with this probe and all are of similar size. The melting profile of the mRNA . cDNA hybrids indicates that the mRNAs induced by the three drugs have at least 98% homology with the cDNA probe. Restriction endonuclease digestions of total chick embryo genomal DNA and a chick cytochrome P450 genomal clone indicates that the cytochrome P450 gene homologous with the cDNA probe is represented in the genome only once. These results strongly suggest that the three drugs cause increased levels of the same cytochrome P450 mRNA, possibly due to enhanced expression of the same gene. Results are also presented which show that other cytochrome-P450-inducing drugs, 3-methylcholanthrene, beta-naphthoflavone or pregnenolone-16 alpha-carbonitrile do not increase the level of the 2-allyl-2-isopropylacetamide-inducible mRNA but rather reduce it to a level which was lower than that of the untreated controls.     

Influence of sewage treatment and urbanization on selection of multiple resistance in fecal coliform populations.

The fecal coliform populations found in the raw sewages and final sewage effluents of mechanical treatment plants, a long-term retention lagoon, shorter-term retention lagoons, a remote northern Canada river, and a heavily urbanized prairie river were examined for antibiotic resistance and the possession of R factors. It was determined that there was a decrease in the percentage of multiresistant fecal coliform populations in the mechanical sewage treatment plants and shorter-term retention lagoons; however, there was an increase in populations from the long-term retention lagoon. The percentage of the populations possessing transmissible R factors was constant in the mechanical treatment and shorter-term retention facilities; however, the ability to transmit was lost in 50% of the infective population of the long-term retention facility. A striking contrast was found between the populations of the remote northern Slave River and those of the urbanized Red River. Of the fecal coliforms in the Slave River, 7.1% were multiresistant, and only 0.79% possessed transmissible R factors. The Red River fecal coliform populations were 52.9% multiresistant, and 18.77% of the total population possessed transmissible R factors. The influence of urbanization and the type of sewage treatment have been shown to affect the selection and survival of multiresistant fecal coliforms and R+ fecal coliforms. Determination of other factors influencing the development and the survival of these populations is needed for rational wastewater management and water quality consideration.     

Effects of angiotensin II and dibutyryl cyclic adenosine monophosphate on phosphatidylinositol metabolism, 45Ca2+ fluxes, and aldosterone synthesis in bovine adrenal glomerulosa cells

Angiotensin II (AII) and N6,O2'-dibutyryladenosine 3':5'-cyclic monophosphate (dibutyryl cyclic AMP) both stimulated aldosterone synthesis in bovine adrenal glomerulosa cells. AII altered 45Ca2+ fluxes and increased 32PO4 incorporation into phosphatidylinositol in these cells, whereas dibutyryl cyclic AMP did not affect either process. Neither AII nor dibutyryl cyclic AMP increased the mass of phosphatidylinositol. Both agents are known to stimulate pregnenolone synthesis. Thus, although dibutyryl cyclic AMP and AII may increase aldosterone synthesis at a common site (pregnenolone synthesis), they do so by different mechanisms. AII stimulation of phosphatidylinositol labeling by 32PO4 (the "PI effect") was blocked when cells were incubated in a medium containing both EGTA and the calcium antagonist, 8-(N,N-diethylamino)-octyl 3,4,5-trimethoxy-benzoate hydrochloride (TMB-8), suggesting a calcium requirement for the PI effect.     

Cholesteryl hemisuccinate alters membrane fluidity, angiotensin receptors, and responses in adrenal glomerulosa cells

We examined the effects of cholesteryl hemisuccinate on membrane fluidity and angiotensin II (AII) actions in bovine adrenal glomerulosa cells. Incubating cells with cholesteryl hemisuccinate decreased membrane fluidity and markedly inhibited AII binding. The effect on binding was characterized by a decrease in AII receptor number. The effects of AII on phosphatidyl inositol turnover and calcium fluxes, proposed intermediaries of AII actions on aldosterone secretion, were less impaired than AII binding by cholesteryl hemisccinate. AII stimulation of aldosterone secretion was preserved despite the decrease in AII binding after cholesteryl hemisuccinate treatment. These results indicate that AII binding can be dissociated from its effects on aldosteronogenesis by a reagent that alters membrane fluidity.     

Effect of Some Calcium Antagonists on Muscarinic Receptor-Mediated Cyclic GMP Formation

Several calcium antagonists were screened for their effect on muscarinic acetylcholine receptor-mediated cyclic GMP formation in murine neuroblastoma cells (clone N1E-115). Mn2+, Ni2+, and verapamil rapidly antagonized the response noncompetitively, with the following order of potency: verapamil greater than Mn2+ greater than Ni2+. The effects of Mn2+ and Ni2+, but not those of verapamil, were largely reversed by increasing extracellular calcium concentration. Additional effects of these agents included displacement of [3H]quinuclidinyl benzilate binding by verapamil and elevation of cyclic GMP levels by Mn2+ and Ni2+ in the absence of agonists. These results are in support of the hypothesis that receptor-mediated cyclic GMP formation by these cells is dependent upon entry of calcium into the cell and demonstrate the complexity of the effects of calcium antagonists.     

Calmodulin-binding drugs affect responses to cytokinin, auxin, and gibberellic Acid

Trifluoperazine, a phenothiazine tranquilizer, and tetracaine, a local anesthetic, have been found to inhibit a variety of plant hormone responses at concentrations compatible with their known inhibition of Ca²⁺-calmod-ulin-dependent enzyme activities. Among these responses are cytokinin-dependent betacyanin synthesis and increase in fresh weight in Amaranthus tricolor cotyledons, auxin-dependent increase in length of wheat coleoptile segments and gibberellic acid-dependent induction of α-amylase synthesis in barley aleurone layers. The reversibility of some of these inhibitory effects has been demonstrated, indicating that, up to a point, a generalized membrane destruction can be ruled out. The evidence, taken in conjunction with numerous examples from the literature showing calcium involvement in the action of all of the plant hormones, support a unifying theory of hormone action.     

Bile acids XLII. Preparation of 5-alpha-cholestan-26-oic acids from kryptogenin

3β, 7α, 26-Triacetoxy-5α-cholestane was prepared from 25R-3β, 26-diacetoxy-5α-cholestan-7α-ol, and partially hydrolyzed with potassium carbonate in methanol-benzene. The three acetylated products thus obtained were characterized by thin layer and gas liquid chromatography, and mass spectrometry. By oxidation and alkaline hydrolysis, 3β, 7α-diacetoxy-5α-cholestan-26-ol was converted to 3β, 7α-dihydroxy-5α-cholestanoic acid. 7α, 26-Diacetoxy-5α-cholestan-3β-ol was characterized as indicated. The third product, 7α-acetoxy-5α-cholestane-3β, 26-diol was oxidized to 3-oxo-7α-acetoxy-5α-cholestanoic acid which was reduced catalytically and hydrolyzed to provide 3α, 7α-dihydroxy-5α-cholestanoic acids and its 3β-isomer. By comparison of the specific rotation of this sample of 3α, 7α-dihydroxy-5α-cholestanoic acid derived from 25R-kryptogenin with a similar product derived from arihydro-5α-cyprinol obtained from carp bile, the latter derivative appears to be primarily the 25S material.     

Factors Influencing the Onset of Chronic Respiratory Disease

To investigate the effect of different environmental and personal factors on ventilatory function 10,971 children resident and going to school in four areas of Kent were examined. Details of past respiratory illnesses were obtained by a questionary completed by the parents; the examination included measurement of height, weight, and peak expiratory flow.Area of residence, social class, family size, and a past history of pneumonia, bronchitis, or asthma were found to be associated with differing levels of peak expiratory flow. These four factors acted independently, and the effects were additive. It is suggested that environment in the early years of life can produce adverse changes which may exist throughout life and contribute to the development of chronic respiratory disease.     

Freeze-drying characteristics ofSaccharomyces cerevisiae andSaccharomyces carlsbergensis

The dispersal of yeast clumps to the unicellular state by certain sugars, does not increase the percentage survival after freeze-drying. Neither are those changes in cell-wall composition which occur upon ageing of the cell, and which are detectable by means of snail-gut enzymes, related to this cellular property. However, pre-treatment, with -mercaptoethanol, of a strain ofSaccharomyces carisbergensis increased the survival rate. This may be due to the reduction of certain sites in the cell wall. The oxygen consumption of yeast cultures before and after freeze-drying, agree with the hypothesis that low viabilities can arise from localized cellular damage which prevents cell reproduction by budding.