Relationship of prodigiosin condensing enzyme activity to the biosynthesis of prodigiosin and its precursors in Serratia marcescens

Prodigiosin condensing enzyme (PCE) activities were present in Serratia marcescens wild type 08, mutants OF, WF and 9-3-3. Their specific activities exhibited different maxima and at different times during the late log phase or the early stationary phase of cell growth. The levels of prodigiosin and its precursors also showed a significant increase at this period. The results support that prodigiosin and/or its precursors are secondary metabolites. The ubiquity of the PCE activity in mutants deficient in prodigiosin biosynthesis suggest that this particular enzyme may also be present in non-pigmented clinical isolates.     

Initial myocardial succino-oxidase activity changes induced by intravenous infusion ofEscherichia coli endotoxin in rabbit

Zusammenfassung Escherichia coli-Endotoxin (1 mg per kg) wurde in die Ohrvene von Kaninchen injiziert: Die Succinat-dehydrogenase- und Cytochromoxydase-Aktivität in den Mitochondrien des Herzmuskels wurde nach 15 min verändert. Es ist wahrscheinlich, dass das Endotoxin sowohl auf das Herz, als auch auf die peripheren Gefässe direkt wirkt.

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This study was supported by the Research Grant HE-09016 from the National Heart Institute, US Public Health Service; and the General Research Support Funds from the Philadelphia General Hospital.     

Does increased gastric mucus play a role in the ulcer-protecting effects of zinc sulphate?

Summary Zinc sulphate pretreatment i.p. produces dose-related reductions in stress ulcer incidence in pylorus-occluded rats. The associated increases in gastric wall mucus, in stressed and nonstressed animals, suggest that a similar effect may contribute to its ulcer-reducing ability in man.     

Cardiac mitochondrial NADH2-cytochrome c reductase and cytochrome oxidase after cardiopulmonary by-pass in dog

Zusammenfassung Nach kurzfristiger extrakorporaler Zirkulation beim Hund wurden Cytochrom-Oxydase-Aktivität und NADH₂-Oxydationsrate in den Mitochondrien des Herzmuskels im Vergleich zu Kontrolltieren vermindert gefunden.

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This study was supported by Research Grant HE-09016 from the National Institutes of Health, U.S. Public Health Service.     

Haploinsufficiency of protamine-1 or -2 causes infertility in mice

Protamines are the major DNA-binding proteins in the nucleus of sperm in most vertebrates and package the DNA in a volume less than 5% of a somatic cell nucleus. Many mammals have one protamine, but a few species, including humans and mice, have two. Here we use gene targeting to determine if the second protamine provides redundancy to an essential process, or if both protamines are necessary. We disrupted the coding sequence of one allele of either Prm1 or Prm2 in embryonic stem (ES) cells derived from 129-strain mice, and injected them into blastocysts from C57BL/6-strain mice. Male chimeras produced 129-genotype sperm with disrupted Prm1 or Prm2 alleles, but failed to sire offspring carrying the 129 genome. We also found that a decrease in the amount of either protamine disrupts nuclear formation, processing of protamine-2 and normal sperm function. Our studies show that both protamines are essential and that haploinsufficiency caused by a mutation in one allele of Prm1 or Prm2 prevents genetic transmission of both mutant and wild-type alleles.     

Does increased gastric mucus play a role in the ulcer-protecting effects of zinc sulphate?

Zinc sulphate pretreatment i.p. produces dose-related reductions in stess ulcer incidence in pylorus-occluded rats. The associated increases in gastric wall mucus, in stressed and nonstressed animals, suggest that a similar effect may contribute to its ulcer-reducing ability in man.     

Histamine H1- and H2-receptor-mediated gastric microcirculatory effects in the aetiology of stress ulceration in the rat stomach

Stress produced severe mucosal ulcers, increased mucosal microcirculation and lowered mast cell counts in the glandular wall of rat stomachs. Mepyramine i.m. or metiamide i.p. effectively prevented both ulceration and microcirculatory changes but not stress-reduced mast cell counts.     

Mutations of the gene encoding the protein kinase A type I-alpha regulatory subunit in patients with the Carney complex

Carney complex (CNC) is a multiple neoplasia syndrome characterized by spotty skin pigmentation, cardiac and other myxomas, endocrine tumours and psammomatous melanotic schwannomas. CNC is inherited as an autosomal dominant trait and the genes responsible have been mapped to 2p16 and 17q22-24 (refs 6, 7). Because of its similarities to the McCune-Albright syndrome and other features, such as paradoxical responses to endocrine signals, genes implicated in cyclic nucleotide-dependent signalling have been considered candidates for causing CNC (ref. 10). In CNC families mapping to 17q, we detected loss of heterozygosity (LOH) in the vicinity of the gene (PRKAR1A) encoding protein kinase A regulatory subunit 1-alpha (RIalpha), including a polymorphic site within its 5' region. We subsequently identified three unrelated kindreds with an identical mutation in the coding region of PRKAR1A. Analysis of additional cases revealed the same mutation in a sporadic case of CNC, and different mutations in three other families, including one with isolated inherited cardiac myxomas. Analysis of PKA activity in CNC tumours demonstrated a decreased basal activity, but an increase in cAMP-stimulated activity compared with non-CNC tumours. We conclude that germline mutations in PRKAR1A, an apparent tumour-suppressor gene, are responsible for the CNC phenotype in a subset of patients with this disease.