Characterization of the structural gene encoding a copper-containing nitrite reductase and homology of this gene to DNA of other denitrifiers

A copper-containing nitrite reductase gene (nirU) from Pseudomonas sp. strain G-179 was found in a 1.9-kb EcoRI-BamHI DNA fragment. The coding region contained information for a polypeptide of 379 amino acids. The encoded protein had 78% identity in amino acid sequence to the nitrite reductase purified from Achromobacter cycloclastes. The ligands for type 1 copper- and type 2 copper-binding sites found in A. cycloclastes were also found in Pseudomonas sp. strain G-179, suggesting that these binding sites are conserved. Upstream from the promoter, two putative fnr boxes were found, suggesting that an FNR-like protein may be involved in regulation of the nitrite reductase gene under anaerobic conditions. When the 1.9-kb clone was used to probe Southern blots for similar sequences in DNAs from different denitrifiers, hybridization bands were seen for 15 of 16 denitrifiers known to have nitrite reductase containing copper. Except for Pseudomonas stutzeri JM300, all denitrifiers tested that have nitrite reductases containing heme c,d1 showed no or weak hybridization to this probe. Thus, this structural gene may be useful as a probe to detect denitrifiers with copper-containing nitrite reductases.     

A microsatellite genetic linkage map of human chromosome 13

We have characterized 21 polymorphic (CA)n microsatellites for the development of a genetic map of chromosome 13. Fifteen markers were isolated from a flow-sorted chromosome 13 library, four CA repeats were derived from NotI-containing cosmid clones, and two polymorphic markers were described previously (J. L. Weber, A. E. Kwitek, and P. E. May, 1990, Nucleic Acids Res. 18: 4638; L. Warnich, I. Groenwald, L. Laubscher, and A. E. Retief, 1991, Am. J. Hum. Genet. 49(Suppl.): 372 (Abstract)). Regional localization for all of the markers was performed by amplification of DNA from five somatic cell hybrids containing different deletions of chromosome 13. Genetic markers were shown to be distributed throughout 6 of the 11 resolvable chromosomal subregions. Using data from nine families provided by the Centre d'Etude du Polymorphisme Humain (CEPH), a framework map of 12 of these 21 markers was developed. Six of the 12 markers form three pairs, with each two members of a pair being tightly linked, such that nine systems of markers can be distinguished. The average heterozygosity of these 12 markers is 0.75. The total length of the sex-averaged map is 65.4 cM (Kosambi), with an average distance of 8.2 cM between systems of markers (eight intervals). Seven remaining markers were placed provisionally into the framework map.     

Hyperthyroidism due to contamination of the alternative drug Ader-Rein (Vascu-Vitaal)

A 52-year-old woman developed hyperthyroidism due to the alternative Vascu-Vitaal pills. She was suffering from nephrotic syndrome due to membranoproliferative glomerulonephritis and subclinical hypothyroidism, possibly due to renal loss of thyroid hormone. For peripheral vascular disease she took the non-registered Vascu-Vitaal pills on her own initiative. According to the product information, these pills contain multiple vitamins, minerals, amino acids and tissue extracts of bovine adrenals, hypophysis and thymus. The patient developed hyperthyroidism after starting on a new batch of the preparation; it subsided after stopping the treatment. A technetium thyroid scan showed decreased uptake and subsequently the Vascu-Vitaal pills were found to contain both thyroxine and triiodothyronine. The thyroid hormone contamination was probably caused by bovine thyroid tissue. It is suggested to require a health warning statement on the package of alternative therapeutics stating that production and contents are not subject to governmental supervision.