Amino-modified silicate gels prepared by sol-gel processing as metal-ion sorbents

Two series of amino-modified silicate gels prepared by sol-gel processing were used to absorb Cu(II), Ni(II), Co(II), Mn(II) and Cr(III) from aqueous solutions. These easily prepared sorbents with various content of primary amino groups in series (A) or primary and secondary amino groups in series (AA) have reasonable stability. The gel composition, time and concentration dependence of the uptake of the metal ions by these materials were studied systematically. These materials would be further used as supports to disperse catalytically active phases by conventional wet chemical procedures. Apart from this they demonstrate potential for the preconcentration aid for transition metal analysis.     

Long-term survey data (1965-1972) on the occurrence of Anisakis larvae (Nematoda: Ascaridida) in herring, Clupea harengus L., from the North Sea

The occurrence of larval Anisakis in North Sea herring was examined during the period 1965-1972 using a sampling method which yielded comparable data for all eight years. Data on abundance of infestation in several herring stocks pointed to remarkable fluctuations over the study period with an increase in the period 1966-1968 followed by a decrease in the period 1968-1972. Of various hypotheses that may explain this situation, it is concluded that changes in the migration behaviour of the herring may be responsible. Other data and statistics are discussed with special reference to variations in infestation level in different samples and to the occurrence of adult nematodes in marine mammals.     

Analysis of the chicken fast myosin heavy chain family. Localization of isoform-specific antibody epitopes and regions of divergence.

cDNAs encoding the rod region of four different fast myosin heavy chains (MYCHs) in the chicken were identified, using anti-MYCH monoclonal antibodies, in two expression libraries prepared from 19-day embryonic and adult chicken muscle. These clones were used to determine the amino acid sequences that encompass the epitopes of five anti-MYHC monoclonal antibodies. Additionally, the amino acid sequences were compared to each other and to a full length embryonic MYHC. Although there is extensive homology in the chicken fast myosin rods, sequences within the hinge, within the central portion of the light meromyosin fragment, and at the carboxy terminus exhibit the largest number of amino acid substitutions. We propose that divergence within these subdomains may contribute to isoform-specific properties associated with skeletal myosin rods.     

A d(GpG)-platinated decanucleotide duplex is kinked. An extended NMR and molecular mechanics study

A conformational study of the double-stranded decanucleotide d(GCCG*G*ATCGC).d(GCGATCCGGC), with the G* guanines chelating a cis-Pt(NH3)2 moiety, has been accomplished using 1H and 31P NMR, and molecular mechanics. Correlation of the NMR data with molecular models has disclosed an equilibrium between several kinked conformations and has ruled out an unkinked structure. The deformation is localized at the CG*G*.CCG trinucleotide where the helix is kinked by approximately 60 degrees towards the major groove and unwound by 12-19 degrees. The models revealed an unexpected mobility of the cytosine complementary to the 5'-G*. This cytosine can stack on either branch of the kinked complementary strand. The energy barrier between the two positions has been calculated to be less than or equal to 12 kJ/mol. The NMR data are in support of rapid flip-flopping of this cytosine. An explanation for the strong downfield shift observed in the 31P resonance of the G*pG* phosphate is given.