Binding of divalent copper and calcium ions to poly I

The effect ot Cu²⁺ and Ca²⁺ ions, on the ultraviolet differential (UVD) spectra of single-stranded poly I was studied and the coordination (Δε_b) and conformation (Δε_c) conponents of the spectra calculated The comparison of Δε_b and the UVD spectrum of protonated IMP leads to the conclusion that N(7) ot inosine-5'-monophosphate (IMP) is a coordinating site tor Ca²⁺ and Cu²⁺ ions on the polymer bases. The binding ot Ca²⁺ and Cu²⁺ ions causes differently directed displacements of the four absorption bands of poly I, which are observed in the wavenumber range (50-34) × 10³ cm⁻¹ The calculation of concentration dependencies tor the association constants (K“) ot Ca²⁺ and Cu²⁺ ions binding to poly I bases shows that the binding is cooperative The K“ values for the poly I + Ca²⁺ complex are two orders of magnitude lower than those for the poly 1 + Cu²⁺ complex At low ion concentrations, binding to the poly I phosphates predominates and increases the degree of the polynucleotide helicity. At higher concentrations the spectra are mainly affected by the ion binding to bases, which results in melting of the helical parts of poly I At Ca²⁺ concentrations exceeding 10⁻³ M light-scattering aggregates are formed. The degree of monomer order in them is close to that observed in multistranded helices of poly I     

The coding region of the human c-mos pseudogene contains Alu repeat insertions

We have determined the nucleotide sequence of an 841-bp fragment derived from a segment of the human genome previously cloned by Chumakov et al. [Gene 17 (1982) 19–26] and Zabarovsky et al. [Gene 23 (1983) 379–384] and containing regions homologous to the viral mos gene probe. This sequence displays homology with part of the coding region of the human and murine c-mos genes, contains several termination codons, and is interrupted by two Alu-family elements flanked by short direct repeats. Probably, the progenitor of the human c-mos gene was duplicated approximately at the time of mammalian divergence, was converted to a pseudogene, and acquired insertions of two Alu elements.     

Influence of maternal adrenalectomy on the ultrastructure of the adrenal gland in neonatal rats

Maternal adrenalectomy at 7 or 14 days of gestation produced increased cell necrosis within zona reticularis cells on the day of birth and at 24 or 48 h after birth. Small remnants or large portions of adrenocortical cells were present within macrophages. In otherwise normal adrenocortical cells, lipid droplets were incorporated within some mitochondria. Autophagocytosis of single mitochondria was observed within adrenocortical cells. Undoubtedly ultrastructural changes represent stimulation of adrenocortical cells in neonatal rats in response to maternal adrenalectomy.     

Cloning of bacteriophage T5 promoters

Summary Bacteriophage T5 was subjected to combined hydrolysis with the restriction endonuclease PstI and HindIII and the resulting fragments were inserted into the plasmid pBR322. Selection of transformants for Ap^s-Tc^r-phenotype made it possible to screen the hybrid plasmids that contained promoter sequences in the cloned fragments.Two PstI/HindIII fragment, 720 bp (51% of the T5 DNA length) and 1,200 bp (70%) were cloned in this study. Tc^r levels for these plasmids were as high as 18 g/ml and 75 g/ml, respectively. The presence of Escherichia coli RNA polymerase binding sites on both fragments was shown using the nitrocellulose filter assay. These binding sites are situated between 35 bp and 95 bp from the HindIII cleavage site on the 1,200 bp fragment; and within 420 bp from the HindIII site on the 720 bp fragment.Abbreviations Ap ampicillin - Tc tetracycline - bp base pairs - NTPs nucleoside triphosphates - PBB polymerase binding buffer     

Genetic control of igG2a production in the response to sheep erythrocytes

A low IgG2a response in B10 mice during the primary response to sheep red blood cells (SRBC) is described. Analysis of the response in B10 × BALB/c hybrid progenies and in congenic strains indicates that this low response is a dominant phenotype placed under the control of a single Mendelian gene or a group of closely linked genes. This gene(s) is neither linked to CH allotypes orH2 haplotypes, nor is it sex-linked. It can be considered as an isotype- and antigenspecific regulatory gene of the immune response.     

Synthesis of the tetrasaccharide repeating-unit of the O-specific polysaccharide from Salmonella senftenberg

The oligosaccharide β-d-Man-(1 → 4)-α-l-Rha (1 → 3)-d-Gal-(6 ← 1)-α-d-Glc, which is the repeating unit of the O-specific polysaccharide chain of the lipopolysaccharide from Salmonella senftenberg, was obtained by glycosylation of benzyl 2,4-di-O-benzyl-6-O-(2,3,4-tri-O-benzyl-6-O-p-nitrobenzoyl-α-d-glucopyranosyl)-β-d-galactopyranoside or benzyl 2-O-acetyl-6-O-(2,3,4-tri-O-benzyl-6-O-p-nitrobenzoyl-α-d-glucopyranosyl)-β-d-galactopyranoside with 3-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-β-d-mannopyranosyl)-β-l-rhamnopyranose 1,2-(methyl orthoacetate) followed by removal of protecting groups.     

Fructosylation of ergot alkaloids by yeast invertase

Summary A method for transfructosylation of ergot alkaloids elymoclavine, chanoclavine, lysergol, 9, 10-dihydrolysergol using commercial yeast -fructofuranosidase and sucrose is described