Determinants that target the integrase of phage HK022 into the mammalian nucleus

The integrase (Int) protein of coliphage HK022 catalyzes the site-specific integration and excision of the phage into and from its Escherichia coli host chromosome. Int expressed from a plasmid in COS1 monkey cells is localized in the nucleus, as is a fusion protein between Int and the green fluorescent protein (GFP). Mutation analysis of the GFP-Int fusion has revealed in Int two regions of positively charged amino acid residues that cooperate in the nuclear localization. One region harbors residues Arg90 and Arg93. The other, which spans residues 307-340 belongs to the catalytic domain of Int, is rich in basic residues and is strongly conserved within the Int protein family. Being localized in the nucleus renders Int of HK022 as a potential recombinase for site-specific gene manipulations in mammals.     

On the effect of insulin on glucose-6-phosphate dehydrogenase and fatty acid synthetase activity in mouse liver.

Regulation of glucose-6-phosphate dehydrogenase and fatty acid synthetase activity in mouse liver is examined in diabetic and normal mice. Up to a 4-fold increase of both enzymes can be observed in streptozotocin diabetic mice when transferred to a fatless, inducing diet. Administration of insulin does not increase enzyme activity at several doses and under a variety of conditions. This is a strong indication that insulin is not a necessary component of the induction system.     

The Integration Host Factor (IHF) Affects the Expression of the Phosphate-Binding Protein and of Alkaline Phosphatase in Escherichia coli

The genes encoding alkaline phosphatase (phoA) and the inducible inorganic phosphate transport system Pst (pstS,C,A,B,U) belong to the PHO regulon. Mutants of Escherichia coli lacking the global regulatory protein integration host factor (IHF) show an increased level of alkaline phosphatase and a decreased level of Pst. IHF binds weakly but specifically to a DNA fragment containing the promoter region of the pst operon but does not bind to a fragment that includes the promoter region of phoA. It is proposed that IHF is a positive regulator of the pst operon and as such controls indirectly the expression of phoA. Received: 4 May 1998 / Accepted: 19 August 1998     

Renal involvement following near-drowning in the sea

1. The metabolic changes in rats following introduction of sea water directly into the stomach were studied. The results were compared with those of a human case report of acute renal failure following swallowing of sea water. 2. In both rats and man, acute renal failure appeared within the first 24 hr. A slight improvement was found five days later. 3. There was an acute hypocalcemia. This was supposedly due to the large magnesium content of the sea water. 4. It is probable that water entering the alimentary canal, dry drowning, affects the kidneys by the initial flow of water to the intestines. This results in hemo-concentration and reduced kidney function. The abnormality is a transient one and could be due to a partial anoxia due to shrinking of the erythrocytes. 5. It is concluded that an apparently uneventful swallowing of sea water can turn into secondary drowning with transient acute renal failure.