Molecular cloning of the GTP-cyclohydrolase structural gene RIB1 of Pichia guilliermondii involved in riboflavin biosynthesis

The structural gene of GTP-cyclohydrolase, involved in riboflavin biosynthesis, was cloned from a Pichia guilliermondii genomic library. A 1855 bp genomic DNA fragment complementing the riboflavin auxotrophies of an Escherichia coli ribA mutant, defective in GTP-cyclohydrolase II, and a P. guilliermondii rib1 mutant was isolated and sequenced. An open reading frame with the potential to encode a protein of 344 amino acids with a predicted molecular mass of 38 711 Da was detected. The P. guilliermondii enzyme shows a high degree of homology to GTP-cyclohydrolases type II from E. coli and Baccillus subtilis and to GTP-cyclohydrolase from Saccharomyces cerevisiae. Functional GTP-cyclohydrolase from P. guilliermondii may consist of four identical subunits. The sequence of the RIB1 gene of P. guilliermondii was submitted to the EMBL sequence database and is accessible under Accession Number Z49093.     

Interrelations of disorders of the endocrine and immune systems of patients with malignant melanoma

Investigations of endocrine and immune systems in melanoma patients gave evidence that such patients develop disorders of functions between thymus, on the one hand, and those of the pineal gland, pituitary, adrenal cortex and gonads, on the other, which are important in the pathogenesis of alterations in cell-mediated and humoral immune responses. The author recommends the administration to melanoma patients of either preparations of thymus itself or those with thymosin-like activity, as well as biologically active factors of the pineal gland which normalize metabolic changes in the body.     

Application of the photomult plier FEU-12 to scintillation spectroscopy

An investigation was made of the spectral response and other characteristics of the FEU-12 photomultiplier having grid-type dinodes and developed by G. S. Vildgrube.The authors consider it their pleasant duty to thank Mr. G. S. Vildgrube who made available to them photomultipliers and certain materials for technical tests.