Structural relationships between the endogenous volatile urinary metabolites of experimentally diabetic rats and certain neurotoxins

Summary High resolution glass capillary gas chromatography and GC/MS were utilized to examine qualitative and quantitative variations from normal of urinary volatile metabolites of long-term alloxan and streptozotocin diabetic rats. Volatile metabolites were structurally compared with known neurotoxins to examine any possible relationship between these metabolites and the development of the diabetic polyneuropathy.Acknowledgment. This research was supported by grant No. 24349 from the National Institute of General Medical Sciences, U.S. Public Health Service.     

Calcium alginate: A new approach in the artificial culturing of insects,applied toSpodoptera littoralis (Boisduval)

Résumé La réaction entre l'alginate de soude et les ions de calcium a été utilisée dans la préparation à froid d'un gel nutritif servant à l'élevage artificiel deSpodoptera littoralis (Boisduval).     

Tetramerization of an RNA oligonucleotide containing a GGGG sequence.

Poly rG can form four-stranded helices. The Hoogsteen-paired quartets of G residues on which such structures depend are so stable that they will form in 5'-GMP solutions, provided that Na+ or K+ are present (see for example, refs 2-4). Telomeric DNA sequences, which are G-rich, adopt four-stranded antiparallel G-quartet conformations in vitro, and parallel tetramerization of G-rich sequences may be involved in meiosis. Here we show that RNAs containing short runs of Gs can also tetramerize. A 19-base oligonucleotide derived from the 5S RNA of Escherichia coli (strand III), 5'GCCGAUGGUAGUGUGGGGU3', forms a K(+)-stabilized tetrameric aggregate that depends on the G residues at its 3' end. This complex is so stable that it would be surprising if similar structures do not occur in nature.     

Engineering the third wave of biocatalysis

Over the past ten years, scientific and technological advances have established biocatalysis as a practical and environmentally friendly alternative to traditional metallo- and organocatalysis in chemical synthesis, both in the laboratory and on an industrial scale. Key advances in DNA sequencing and gene synthesis are at the base of tremendous progress in tailoring biocatalysts by protein engineering and design, and the ability to reorganize enzymes into new biosynthetic pathways. To highlight these achievements, here we discuss applications of protein-engineered biocatalysts ranging from commodity chemicals to advanced pharmaceutical intermediates that use enzyme catalysis as a key step.