Glutathione status and sensitivity to GSH-reacting compounds of Escherichia coli strains deficient in glutathione metabolism and/or catalase activity

The intracellular concentrations of total glutathione, GSSG and protein · S-SG, the total excreted glutathione concentration, and the susceptibility towards GSH-reacting compounds were assayed in strains of Escherichia coli deficient in biosynthesis and/or reduction of glutathione. A deficiency in glutathione reductase displaced the glutathione status towards the oxidized forms. This displacement was more clearly appreciated in strains additionally deficient in glutathione biosynthesis. A deficiency in catalase activity also produced an increase in the oxidation of glutathione. The most severe changes were observed in the concentrations of protein-glutathione mixed disulfides and in the amount of glutathione excreted to the medium. Increased sensitivities towards compounds known to interact with cellular GSH were observed in glutathione reductase deficient strains, although these effects were enhanced in strains additionally deficient in GSH biosynthesis     

Search for Drosophila genes encoding a conserved domain present in the achaete-scute complex and myc proteins

Summary Several genes of the achaete-scute complex (ASC) of Drosophila melanogaster encode a 60 amino acids long conserved domain which shares a significant homology with a region of the vertebrate myc proteins. Based on these results, the existence of a family of Drosophila genes that would share both this conserved domain and the neurogenic function of the AS-C has been postulated. To test this proposal, we have searched a D. melanogaster genomic library with a probe that encodes the conserved domain. Only under very low stringency hybridization conditions, clones not belonging to the AS-C cross-hybridized with the probe. Those that gave the strongest signals were characterized. Sequencing of the cross-hybridizing regions showed that they had no significant homology with the conserved domain, the sequence similarity extending at the most for 37 nucleotides. Although our results do not conclusively disprove the existence of a family of AS-C-like genes, they indicate that the conservation of the domain would be lower than that found for shared motifs in other families of Drosophila developmental genes.     

The gene for trypsin inhibitor CMe is regulated in trans by the lys 3a locus in the endosperm of barley (Hordeum vulgare L.)

Summary A cDNA encoding trypsin inhibitor CMe from barley endosperm has been cloned and characterized. The longest open reading frame of the cloned cDNA codes for a typical signal peptide of 24 residues followed by a sequence which is identical to the known amino acid sequence of the inhibitor, except for an Ile/Leu substitution at position 59. Southern blot analysis of wheat-barley addition lines has shown that chromosome 3H of barley carries the gene for CMe. This protein is present at less than 2%–3% of the wild-type amount in the mature endosperm of the mutant Risø 1508 with respect to Bomi barley, from which it has been derived, and the corresponding steady state levels of the CMe mRNA are about I%. One or two copies of the CMe gene (synonym Itc1) per haploid genome have been estimated both in the wild type and in the mutant, and DNA restriction patterns are identical in both stocks, so neither a change in copy number nor a major rearrangement of the structural gene account for the markedly decreased expression. The mutation at the lys 3a locus in Risø 1508 has been previously mapped in chromosome 7 (synonym 5H). A single dose of the wild-type allele at this locus (Lys 3a) restores the expression of gene CMe (allele CMe-1) in chromosome 3H to normal levels.     

Renin release responses to in vitro prostaglandin challenge in the summer-active ground squirrel, Spermophilus lateralis

1. Using a renal cortical slice preparation from the summer-active ground squirrel, Spermophilus lateralis, resting renin release (RR) and tissue cyclic AMP content (TcAMPC) levels were found to be significantly higher and lower, respectively, than those previously reported for its hibernating counterpart. 2. At a 10(-5) M dose, PGE2 but not PGE1, PGF2-alpha or PGA1, significantly stimulated RR in the summer-active ground squirrel (SAGS). 3. Addition of agents which normally increase TcAMPC significantly potentiated the effect of PGE1, while preventing that of PGE2, on RR and TcAMPC. 4. Opposite TcAMPC changes may mediate the in vitro RR responses to PGE1 and PGE2 administration in the SAGS.     

Immunophenotyping of acute myeloid leukaemia: relevance of analysing different lineage-associated markers

The immunophenotype of 135 previously untreated patients with FAB defined acute myeloid leukaemia (AML) was studied at diagnosis. The panel of reagents included monoclonal antibodies (MoAb) recognising myeloid-associated determinants (CD11, CD13, CD14, CD33 and others) as well as MoAb directed towards lymphoid antigens (CD7, CD10, CD19) and TdT. The results indicate that CD13 and/or CD33 are consistently expressed in AML and only rarely in ALL blasts (131/135 + ve cases, versus 4/130 in ALL). Lymphoid antigen expression was rarely detected when CD10 and CD19 were investigated in AML (0.9% and 2% + ve cases, respectively), whereas significant positivities were found for TdT and CD7 (20% and 10% respectively). Concerning FAB subtypes, two new MoAb (LAM3 and LAM7) proved very useful in the specific recognition of AML with monocytic features. The phenotype CD13+ and/or CD33+, CD9+, HLA-DR- was found to be almost exclusive for M3 AML. The response to induction chemotherapy was analysed in CD7+ and in TdT+ patients. In the latter group a statistically significant lower response rate was found with respect to TdT-ve-AML patients.     

Beta 1 and beta 2 adrenergic agonists in exocrine pancreatic secretion in the rabbit

The effect of Dobutamine (a beta 1-adrenergic agonist) and Terbutaline (a beta 2-adrenergic agonist) on exocrine pancreatic secretion was studied in anaesthetized rabbits, simultaneously controlling pancreatic blood flow and blood pressure. The secretion of fluid and ions (bicarbonate, sodium and potassium) was unaffected by the infusion of Dobutamine (8 micrograms.kg-1.min-1) or Terbutaline (10 micrograms.kg-1.min-1). Neither were pancreatic blood flow or mean blood pressure altered. Dobutamine or Terbutaline depress the function of the acinar cells, amylase secretion being more affected by the action of Terbutaline. The results show that beta 1 and beta 2-adrenergic stimulation has no effect on the ductular cells but does decrease the secretion by the acinar cells.     

The breeding biology of the WheatearOenanthe oenanthe in South Sweden during three contrasting years

Summary The breeding phenology, territory size, egg dimensions, clutch size, nestling growth and reproductive success of a dense population of WheatearsOenanthe oenanthe was studied on the island of Öland, S. Sweden during the years 1985–1987. The 1987 season was exceptionally cold and rainy, 1986 had the warmest and driest conditions, while 1985 was intermediate with respect to weather. Cold, windy and rainy weather was associated to prolonged incubation, greater intervals between first and replacement clutches, prolonged nestling growth, lower fledging condition, increased starvation and increased predation. Large clutches were laid earlier in the season and contained relatively larger eggs than small clutches. Incubation periods decreased with clutch size. Female size was positively correlated with egg size and with clutch size. The last egg laid in a clutch had a tendency to be heavier than eggs laid previously, especially in large clutches. Nestling starvation increased with brood size in 2 years.

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Zusammenfassung 1985–1987 wurden Phänologie, Siedlungsdichte, Eimaße, Gelegegröße, Jungenwachstum und Bruterfolg einer Population des Steinschmätzers auf der südschwedischen Insel Öland untersucht. 1987 waren die Lufttemperaturen besonders niedrig und die Niederschläge sehr hoch. Der Sommer 1986 wies dagegen die höchsten Temperaturen und niedrigsten Niederschläge der 3 Jahre auf. Kaltes, windiges und regnerisches Wetter war mit längerer Brütezeit, längeren Intervallen zwischen Erst- und Ersatzbruten, langsamerem Jungenwachstum, schlechterer Kondition der ausfliegenden Jungen und höheren Verlusten durch Verhungern und Beutefeinde korreliert. Die Gelegegröße nahm mit dem Legedatum ab; die größten Gelege hatten im Mittel größere Eier. Die Bebrütungszeit nahm mit der Gelegegröße ab. Größere Weibchen legten größere Eier und zeigten Tendenz, größere Gelege zu produzieren. Die zuletzt gelegten Eier waren meist die schwersten, besonders in großen Gelegen. Ausfälle durch Verhungern stiegen in 2 Jahren mit der Brutgröße.

     

Transposon-generated Tn10 insertion mutations at thearo genes ofEscherichia coli K-12

We have obtained a set ofEscherichia coli K-12 derivatives with transposon-generated Tn10 insertion mutations at thearo genes of their aromatic biosynthetic pathway. Bacteriophage NK561 (Tn10) has been used for transposon mutagenesis ofE. coli, strain BW545. Tetracycline (Tc)-resistant derivatives were screened by their Aro^– phenotype by growth on a minimal medium with adequate requirements. Sixaro mutant types were mapped; two strains werearoA, twoaroD, onearoB oraroE, and onearoC. A selective medium and ad-cycloserine enrichment in the presence of tetracycline were used to select for Aro^–, Tc-sensitive derivatives. The reversion index to aromatic-independent colonies of some derivatives was less than 2 × 10^–11 per bacterium per generation. P1 transduction experiments transferred an aroA::Tn10 insertion fromE. coli BW545 to an enterotoxigenicE. coli strain from porcine origin. Derivatives of this strain beingaro, Tc-sensitive and not reverting toaro ⁺ at a detectable frequency, and many others transduced at will, may prove their usefulness as live vaccines.     

Sequence and expression of the Drosophila phenylalanine hydroxylase mRNA

We report the cloning, nucleotide (nt) sequence and expression of the cDNA (pah) encoding phenylalanine hydroxylase (PAH) of Drosophila melanogaster. The strong hybridization signals observed in genomic blots when D. melanogaster DNA was probed with 32P-labeled human pah cDNA, indicated the existence of a high degree of sequence similarity between the pah genes of both species. The length of the pah genomic fragment is about 30 to 40 kb. The cDNA contains 84 bp of the 5'-untranslated region, 1359 bp of the protein-coding region and 87 bp of the 3' region, with only one polyadenylation signal. The isolated cDNA is probably full-length, since the size of the D. melanogaster PAH mRNA is 1.5 kb. At the nt level, the similarity of the D. melanogaster cDNA with human and rat pah cDNAs is 57.9% and 58.1%, respectively. The highest similarities are restricted to the nt sequence coding for the presumed hydroxylation domain. There is no nt sequence similarity between the first three exons of the human pah gene and an equivalent fraction of the D. melanogaster pah gene. At the amino acid (aa) level, the similarity in the presumed hydroxylation domain is 88.5%, in which two motifs of the structure AGLLSSXXXL are found, where X represents any aa. It was interesting to notice the conservation of aa 408, 311 and 280, where mutations are associated with phenylketonuria in humans. We observed, moreover, that, as it occurs in humans and rats, the expression of the D. melanogaster pah gene is tissue-specific and temporally regulated.