A human histone H2B.1 variant gene, located on chromosome 1, utilizes alternative 3' end processing.

A variant human H2B histone gene (GL105), previously shown to encode a 2300 nt replication independent mRNA, has been cloned. We demonstrate this gene expresses alternative mRNAs regulated differentially during the HeLa S3 cell cycle. The H2B-Gl105 gene encodes both a 500 nt cell cycle dependent mRNA and a 2300 nt constitutively expressed mRNA. The 3' end of the cell cycle regulated mRNA terminates immediately following the region of hyphenated dyad symmetry typical of most histone mRNAs, whereas the constitutively expressed mRNA has a 1798 nt non-translated trailer that contains the same region of hyphenated dyad symmetry but is polyadenylated. The cap site for the H2B-GL105 mRNAs is located 42 nt upstream of the protein coding region. The H2B-GL105 histone gene was localized to chromosome region 1q21-1q23 by chromosomal in situ hybridization and by analysis of rodent-human somatic cell hybrids using an H2B-GL105 specific probe. The H2B-GL105 gene is paired with a functional H2A histone gene and this H2A/H2B gene pair is separated by a bidirectionally transcribed intergenic promoter region containing consensus TATA and CCAAT boxes and an OTF-1 element. These results demonstrate that cell cycle regulated and constitutively expressed histone mRNAs can be encoded by the same gene, and indicate that alternative 3' end processing may be an important mechanism for regulation of histone mRNA. Such control further increases the versatility by which cells can modulate the synthesis of replication-dependent as well as variant histone proteins during the cell cycle and at the onset of differentiation.     

Persistence of the control of the fluctuations of heart rate in the anesthetized and pithed adult rat. Effect of enteraminergic drugs]

Spontaneous fluctuations in heart rate were analyzed by spectral analysis in the ether anesthetized and pithed adult rat. In order to investigate the changes in the spectral pattern of the fluctuations, the selective 5HT-2 and -3 isoreceptor blockers ritanserin and BRL 43694A were used. In both the experimental conditions, ritanserin blockade led to dose-dependent increased fluctuations in HR low and high frequencies. In both the anesthetized and pithed rats, the low frequency range HR fluctuations were drastically reduced by BRL 43694A.     

Multivariate analysis of metastasis risk in laryngeal carcinoma. II. Immune response

The presence of inflammatory reaction, plasma cells, and eosinophils in peritumoral connective tissue and in neoplastic stroma was evaluated with morphometrical method in 181 patients affected by laryngeal carcinoma. A logistic multiple regression model was applied making it with the use of an independent variable represented by the "infiltrating" or "expansive" types of tumor growth, in order to evaluate the probability of nodal metastatsis of each parameter. The results suggest an inverse correlationship between plasma cells and inflammatory infiltration and incidence of nodal metastatsis only in the comparison of the extreme conditions: those with scarce infiltration versus the ones with large infiltration. Inflammatory or plasmacellular infiltration may represent both a defense mechanism against cancer and an aspecific or allergic reaction. The eosinophilic infiltration shows no value in the prevention of nodal involvement.     

Saccharification and protein enrichment of sugar beet pulp byPleurotus florida

Summary Pleurotus florida was grown in submerged culture with different concentrations of sugar beet pulp with a view to its nutritional upgrading. Micelial growth, protein enrichment and dry weight loss of the solid residues of cultures, as well as the evolution of reducing sugars in the liquid medium, were followed for 14 days. A product with 45% (w/w) protein and a saccharification extent as high as 35% (w/w) were obtained after 7 days with 1% (w/v) sugar beet pulp.     

Human erythrocyte glucose-6-phosphate dehydrogenase. Identification of a reactive lysyl residue labelled with pyridoxal 5'-phosphate

Human erythrocyte glucose-6-phosphate dehydrogenase contains a reactive lysyl residue, which can be labelled with pyridoxal 5'-phosphate. The binding of one mole of pyridoxal 5'-phosphate per mole of enzyme subunit produces substantial inactivation. The substrate glucose-6-phosphate prevents the loss of activity, suggesting that the reaction site is close to the substrate-binding site. A tryptic peptide containing the pyridoxal-5'-phosphate-binding lysyl residue has been isolated and characterised. The reactive lysyl residue has been identified in the glucose-6-phosphate dehydrogenase amino acid sequence. Comparison with glucose-6-phosphate dehydrogenase from other sources shows a high homology with a peptide containing a reactive lysyl residue, isolated from the enzyme from Saccharomyces cerevisiae; glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides also contains a region highly homologous with the sequence around the reactive lysyl residue in the human enzyme. The results of this communication provide the first direct evidence for the association of an essential catalytic function with a specific region of the molecule of human erythrocyte glucose-6-phosphate dehydrogenase.